Introduction to Computer Information Systems
Contents
1 Introduction 1 1.1 Introduction to Computer Information Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Introduction to Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.2 Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.3 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.4 Networks and the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.5 Business on the Web . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.6 Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.7 Computers and Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.8 See Also . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.9 External Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Computers in Your Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 Why Learn About Computers? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.4 Computers at Home . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.5 Computers in Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.6 Computers on the Job . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6.1 Spectrum of Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.6.2 Electronic Flight Bags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.7 Portable Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.9 What is a Computer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.9.1 Data vs. Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.9.2 Computers Then and Now . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.9.3 Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.9.4 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.9.5 Computer Users and Professionals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.9.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.10 Computers to Fit Every Need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.11 Phablets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.11.1 Embedded Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.11.2 Mobile Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.11.3 Personal Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
i
ii CONTENTS
1.11.4 Midrange Servers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.11.5 Mainframe Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.11.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.12 Computer Networks and the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.12.1 The History of the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.12.2 From ISP to URL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.12.3 Internet Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.12.4 Searching the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.12.5 TCP/IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.12.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.13 Computers and Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.13.1 Benefits of a Computer-Oriented Society . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.13.2 Disadvantages of a Computer-Oriented Society . . . . . . . . . . . . . . . . . . . . . . . 19 1.13.3 Differences in Online Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.13.4 The Anonymity Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.13.5 Integrity Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.14 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1.15 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.15.1 Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1.15.2 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1.15.3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1.15.4 Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2 Hardware 23 2.1 The System Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.2 Data and Program Representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.2.1 Digital data and numerical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.2.2 Coding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.2.3 Graphics Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.2.4 Audio Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.2.5 Video Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.3 The System Unit - The Motherboard and CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.4 The System Unit - Memory, Buses, Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.1 Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.4.2 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.4.3 Thunderbolt port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.4.4 Power supply unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.4.5 Ethernet Cable in Theatre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.5 How the CPU Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.6 How the CPU Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.7 Improving the Performance of Your Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.7.1 Add More Memory and Buy a Larger or Second Hard Drive . . . . . . . . . . . . . . . . . 32
CONTENTS iii
2.7.2 Upgrade To A Solid-State Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.7.3 Upgrade Your Internet Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.7.4 System Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.7.5 Future Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2.7.6 Review Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2.7.7 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2.7.8 Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.9 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2.10 Storage System Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2.11 Floppy Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.11.1 Storage Media, Storage Technology, and Volatility . . . . . . . . . . . . . . . . . . . . . . 36 2.11.2 Clusters, Sectors, and Tracks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.11.3 Random vs. Sequential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.11.4 Storage Devices and Storage Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2.12 Hard Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2.12.1 Disk Access Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.12.2 Hard drive interface standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.13 Optical Discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 2.13.1 Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 2.13.2 History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 2.13.3 CDs, DVDs, and BDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.14 Flash Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2.15 Other Types of Storage Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.15.1 Remote Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.15.2 Holographic Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 2.15.3 Storage area network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 2.15.4 Network Attached Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 2.15.5 NAS vs SAN and Cloud Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 2.15.6 Smart Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 2.15.7 Large Computer Storage Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
2.16 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 2.16.1 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 2.16.2 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
2.17 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 2.18 Input and Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 2.19 Keyboards, Pointing, and Touch Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.19.1 Specialized Pointing Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 2.20 Scanners, Readers, Digital Cameras . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 2.21 Biometric Readers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 2.22 Audio Input and Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
iv CONTENTS
2.22.1 Audio Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 2.22.2 Audio Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
2.23 Display Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 2.24 Printers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
2.24.1 Laser printers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 2.25 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 2.26 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 2.27 Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 2.28 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3 Software 67 3.1 System Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 3.2 Systems Software Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.2.1 Systems Software vs Application Software . . . . . . . . . . . . . . . . . . . . . . . . . . 67 3.3 The Operating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3.1 Multitasking and Multithreading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 3.3.2 Functions of the Operating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
3.4 Operating Systems for Personal Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 3.4.1 Buffering and Spooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
3.5 Operating Systems for Mobile Phones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 3.6 Utility Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 3.7 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
3.7.1 Review: Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 3.7.2 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 3.7.3 Answer Key for Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 3.7.4 Review Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
3.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 3.9 Application Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 3.10 Application Software Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3.10.1 Installed vs. Web-based . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 3.10.2 Creating Application Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 3.10.3 Software Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
3.11 Software Suites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 3.12 Word Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 3.13 Spreadsheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
3.13.1 What is a Spreadsheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 3.13.2 Tables, Graphics, and Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 3.13.3 How to use a Spreadsheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
3.14 Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 3.15 Presentation Graphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.15.1 Powerpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 3.15.2 Inside Scoop on New Presentation Software . . . . . . . . . . . . . . . . . . . . . . . . . 88
CONTENTS v
3.16 Graphics and Multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 3.17 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3.17.1 Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 3.17.2 Accessibility Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 3.17.3 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3.18 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
4 Networks and the Internet 94 4.1 Computer Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
4.1.1 Networking Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 4.2 Network Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
4.2.1 Network Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 4.2.2 Network Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 4.2.3 Network Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 4.2.4 Network Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 4.2.5 Types of Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 4.2.6 Network Architecture & Network Topologies . . . . . . . . . . . . . . . . . . . . . . . . 99 4.2.7 Data Transmission Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 4.2.8 Communications Protocols and Networking Standards . . . . . . . . . . . . . . . . . . . . 101 4.2.9 Networking Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 4.2.10 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.3 Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 4.3.1 Evolution of the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 4.3.2 The World Wide Web . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 4.3.3 Using the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 4.3.4 Searching the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 4.3.5 Beyond Browsing and Email . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
4.4 Pros and Cons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 4.4.1 Censorship and Privacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 4.4.2 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 4.4.3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
4.5 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 4.5.1 Unauthorized Access and Control Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 120 4.5.2 Computer Sabotage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 4.5.3 Online Theft and Fraud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 4.5.4 Protecting Against Online Theft and Fraud . . . . . . . . . . . . . . . . . . . . . . . . . . 125 4.5.5 Personal Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 4.5.6 Protecting Against Cyberbullying, Cyberstalking, and Other Personal Safety Concerns . . . 129 4.5.7 Network and Internet Security Legislation . . . . . . . . . . . . . . . . . . . . . . . . . . 130 4.5.8 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
5 Business on the Web 134
vi CONTENTS
5.1 Multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 5.1.1 Web-Based Multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 5.1.2 Multimedia Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 5.1.3 Multimedia Web Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 5.1.4 Creating a Web Site using HTML, XML, XHTML, CSSs . . . . . . . . . . . . . . . . . . 140 5.1.5 Multimedia Web Development (Scripting, Development Tools, Authoring Software, and
Testing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 5.1.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 5.1.7 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
5.2 E-Commerce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 5.2.1 What is E-Commerce? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 5.2.2 E-Commerce Business Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 5.2.3 E-Commerce Web Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 5.2.4 Implementing E-Commerce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 5.2.5 Effective E-Commerce Websites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 5.2.6 E-Commerce Sales and Marketing Strategies . . . . . . . . . . . . . . . . . . . . . . . . . 154 5.2.7 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 5.2.8 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 5.2.9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
6 Systems 159 6.1 Information Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
6.1.1 What is an Information System? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 6.1.2 Types of Information Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 6.1.3 IBM Watson and Cognitive Computing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 6.1.4 System Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 6.1.5 SDLC - System Development Life Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 6.1.6 System Development Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 6.1.7 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 6.1.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
6.2 Program Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 6.2.1 Program Design and Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 6.2.2 Program Development Life Cycle - Analysis, Design, Coding . . . . . . . . . . . . . . . . 175 6.2.3 Program Development Life Cycle - Debugging and Testing, Implementation and Maintenance177 6.2.4 Program Development Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 6.2.5 Programming Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 6.2.6 Key Terms Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 6.2.7 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 6.2.8 Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 6.2.9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
6.3 Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 6.3.1 Database Definition and Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
CONTENTS vii
6.3.2 Data Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 6.3.3 The Data Dictionary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 6.3.4 Data Security and Privacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 6.3.5 Classification of Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 6.3.6 Database Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 6.3.7 Databases on the Web . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 6.3.8 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 6.3.9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
7 Computers and Society 198 7.1 Computer Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
7.1.1 Hardware Loss or Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 7.1.2 Encryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 7.1.3 Software Piracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 7.1.4 Electronic Profiling, Privacy Policy and Spam . . . . . . . . . . . . . . . . . . . . . . . . 202 7.1.5 Electronic Surveillance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 7.1.6 Software Piracy and Digital Counterfeiting . . . . . . . . . . . . . . . . . . . . . . . . . . 208 7.1.7 Computer Security and Privacy Legislation . . . . . . . . . . . . . . . . . . . . . . . . . . 209 7.1.8 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 7.1.9 Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 7.1.10 Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
7.2 Ethics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 7.2.1 Intellectual Property Rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 7.2.2 Ethics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 7.2.3 History of Computer Ethics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 7.2.4 Computers and Your Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 7.2.5 Technology Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 7.2.6 Environmental Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 7.2.7 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
8 Text and image sources, contributors, and licenses 228 8.1 Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 8.2 Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 8.3 Content license . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Chapter 1
Introduction
1.1 Introduction to Computer In- formation Systems
An open educational resource to supplement course materials for an undergraduate college credit course in
Computer Information Systems
Computers in Your Life
Introductory computer information systems topics in- clude computer hardware, software, networking, the In- ternet, information systems, programming, databases, and social issues. This complete book may be down- loaded as a collection from Wikibooks:Collections/ Introduction to Computer Information Systems.
1.1.1 Introduction to Computers
1. Computers in Your Life
2. What is a Computer?
3. Computers to Fit Every Need
4. Computer Networks and the Internet
5. Computers and Society
6. Review
Mobile Devices
INPUT PROCESS OUTPUT
IPO Diagram
1.1.2 Hardware
1. The System Unit
2. Storage
3. Input and Output
1.1.3 Software
1. Systems Software
2. Applications Software
1.1.4 Networks and the Internet
1. What is a Network?
2. The Internet and the World Wide Web
3. Internet Security
1
2 CHAPTER 1. INTRODUCTION
Technology Is the Future!
1.1.5 Business on the Web
1. Using Multimedia on the Web
2. Advantages of E-Commerce
Systems Development Life Cycle
1.1.6 Systems
1. Systems Development
2. Programming Languages
3. Database Management Systems
1.1.7 Computers and Society
1. Security and Privacy
2. Intellectual Property and Ethics
1.1.8 See Also
• The Computer Revolution
1.1.9 External Links
• History Timelines: Computer History Timeline
1.2 Computers in Your Life
1.3 Why Learn About Computers?
Today’s world runs on computers. Nearly every aspect of modern life involves computers in some form or fashion. People who do not have experience with computers and software are at a severe disadvantage in both the work- place and daily life. As technology is advancing, the scale of computer use is increasing. Computer users include both corporate companies and individuals. Computers are efficient. They ease people’s onerous jobs by offering them handfuls of software and applications, designed to offer more convenience. To illustrate, rather than writ- ing manually by hands, an author can benefit from the use of word processing software such as Microsoft Word. With the facilities Microsoft Word provides such as word counter and vocabulary and grammar checker, the author can save his time thus able to finish within his deadline. Moreover, computers are able to perform difficult tasks with better calculations.
Technology Is the Future
Computers offer a quicker way to gain information which is by providing an internet access. Up to this moment, many internet browsers and applications have been in- vented, for instance, Mozilla Firefox, Google search en- gine and Microsoft Outlook to organize emails. These applications surely contribute a lot to a much easier way to gain information.
1.4. COMPUTERS AT HOME 3
Computer skills are required to be hired in companies these days. Imagine if two candidates are interviewed, one of which knows nothing about computers while the other does. The employer will definitely hire the lat- ter. Furthermore, with computer skills, one can build his own company and expand his business. He could perhaps work online and export his goods or service.
Learning computer skills is now essential
Not only have computers become more integrated in our lives. They are increasingly becoming more essential in any aspect of life. As computers become more essen- tial, the skill to operate them also become more essen- tial. They are no longer just an advantage but rather a requirement in today’s computer-oriented society. Those who have not had the opportunity to learn computer skills back in the day when computers were not as widespread have started or are forced to learn to use them as they have become necessary in order to be a productive and contributing person in not only the workplace but also in society. Proof of the ever increasing integration in our lives comes from the fact that almost anything can be done with the use of computers. You can now order food, even gro- ceries, through the computer, you can now watch almost anything on your computer, you can now work from home or you can play games to procrastinate at work through the help of computers, you can even conduct interviews through your computer, there are so many things that a computer is capable of that learning the skills to fully reach the potential of computers is a priority.[1]
1.4 Computers at Home
A computer is a good product to have at home. There are so many benefits to owning your own computer. It allows you to be able to write letters, articles, stories, reports and other things easier and faster. If you own a printer, you can easily write a letter to a friend or family member, print it out and send it to them. You can save your written documents on your home computer and have easy access
Home Computer Benefits
to them when you need them again. Having a computer at home allows you to have access to work from home jobs such as research, data entry, writ- ing and other work-from-home jobs. With a computer at home, you can easily communicate with friends and fam- ily through email, social networks and instant messaging. Using a computer to communicate is cheaper than calling friends and family long distance. You can also communi- cate with co-workers, your boss and anyone else you meet on the Internet through your own computer. People usually go to the library for their research. If you have your own computer at home, you don't have to travel to the library when you need to research something. Log on to the Internet and research whatever you need with your computer at home. When you need to know some- thing fast you can look it up on Google or your favorite search engine. Having a computer at home gives you ac- cess to learning all kinds of things through research. This will save you on gas charges instead of having to drive to the library. Having a computer at home means your own personal entertainment source. There are literally thousands of games on the Internet which you can play anytime you want to. You can also watch movies and your favorite TV shows on DVDs. You can also join social networks and interact with your friends on a daily basis. With a computer at home and the Internet, students can now get a college degree from home. There are a lot of different schools that allow students to take college classes online. Using a computer and the Internet can get you a degree at your own pace and faster than going to a college campus. While almost every household has at least one personal computer within it, desktop and laptop computers are no longer the only computers found in the home. Many homes have numerous computers embedded through- out. Thermostats, appliances, entertainment systems and home security systems are just a few examples of things in a home that can be controlled by an internal computer.
4 CHAPTER 1. INTRODUCTION
These smart homes are capable of so much. All of the devices work on a network and often communicate wire- lessly. Home security systems can be monitored from an offsite location. Lights can be turned on an off remotely. Simple tasks, like watering the lawn or running the dish- washer, can be programmed to occur at the homeowners’ convenience, or specifically timed to conserve energy. Some thermostats can even learn and adapt to homeowner preferences. Smart homes are becoming more and more common. Technology is advancing at a rapid rate and smart homes are expected to become the norm in the very near future. The smart devices and appliances can be controlled from personal computers, or other network devices like smart phones. Some people believe that these homes will even- tually be smart enough to recognize the inhabitants and adapt to the needs,[2] giving the phrase computers in the home a whole new meaning.
Smart Home Control Panel
1.5 Computers in Education
FPL’s Computer lab
At most colleges and universities, their students are fa- miliar with blackboard,[3] a course management system
Children working on computers in a classroom
that is used quite frequently in order to stay in touch with teachers, figure out homework assignments, and keep track of grades. While not all classes utilize this technol- ogy, it can be very helpful especially for online courses. With technology growing and advancing so far forward we now have the ability to learn and take classes from the comfort of our own home. While many students still go on campus, there is no short- age of computers. Most colleges have at least one mega lab with nearly a hundred computers. But if you wish to bring your own laptop there are plenty of wireless hot spots where you could get a connection to the internet from anywhere on campus. Understandably lugging text- books around campus may seem exhausting and tiring, you now have the option to get an electronic e-Book of most textbooks needed for class. Most people are knowledgeable on the fact that comput- ers are widely-used in colleges and at universities, but let’s take a step back and take a look at the ways in which com- puters are used in elementary schools. The biggest benefit of a computer being used in a classroom is that it can pro- vide many different study tools depending on the class. They can provide electronic flashcards, math games, and even things as simple as crossword puzzles. Although a computer cannot replace a teacher, it can help expand a students independent thinking skills by allowing activities to be taken as many times as needed. Most of the activi- ties found in classrooms are very interactive which helps keep the student interested. Also, we must not forget that because modern day children are drawn towards electron- ics, they are more compelled to engage in study activities on a computer rather than a sheet of paper. Working on a computer at an early age helps build funda- mental skills needed later on in life. At a young age a child can learn how to fully operate the basic external hardware of a computer like the screen, keyboard, or mouse. With enough exposure to computers and their components, a student can become more efficient for the following years of school and even their future career.[4]
1.7. PORTABLE COMPUTERS 5
1.6 Computers on the Job
If you have seen any older movie (or SpongeBob) you have probably seen people getting to work grabbing their time card and getting it stamped to show what time they have arrived at work. This is called an authentication sys- tem or timesheet.[5] While now the authentication system is more digital than before, the concept still applies. This isn't the only use of computers on the job or at work in general. For instance say there is a presentation you must give to the board of directors, you might want to make a PowerPoint[6] to give visuals to help drive home your point. Or perhaps you work retail and the pair of pants a customer wants is out of stock, you could easily order it online for them, and minimize the headache of shopping for those who hardly shop. Whatever the case, computers can help.
1.6.1 Spectrum of Computers
Every industry has computers. These machines have been incorporated into the fabric of every work- force.Computers have even created many fields which did not exist prior to their existence.[7] Computers mani- fest themselves in different ways to preform unique tasks. One size does not fit all in the realm of computers, rather each has a purpose or assigned task. The computers that fulfill similar tasks can be classed together. The cate- gories range from small scale to industrial. An embedded computer is something that allows somewhere like an of- fice to have appliances that range from routers to printers. Then there are mobile devices such as smart phones, ph- ablets, and smart watches that are, for example, able to keep a New York stock broker up-to-date on the latest stocks, or instantly keep in touch with investors. These devices have compressed, basic operating systems −al- though they are getting more advanced by the day. Per- sonal computers are one order of magnitude up from mo- bile devices. Personal computers have the full and uni- versal capabilities in order to have the capacity to access work from outside the workplace, as well as handle the software that might be used on the job. Midrange com- puters or midrange servers are yet another order of mag- nitude up on the spectrum. These machines are between 20 and 50 times larger than a traditional desktop com- puter, though their previous name was a “minicomputer” and has business and scientific applications. These com- puters are often referred to as servers due to the majority of them being used as such.[8] Next are Mainframe com- puters, which are primarily used by large corporations and governments to store and process massive amounts of information. This leads to the final class which is Super- computers. As the name would suggest, this type of com- puter is quite powerful. It calculates enormous amounts of information with countless variables to get informa- tion. These are responsible for tasks such as weather prediction, security, simulating the moment the universe
came into existence, as well as helping to create the next tier of computer - which is not yet fully operational - the quantum computer
• Embedded Computer
• Personal Computers
• Midrange Servers
• Mainframe Computers
• Supercomputers
1.6.2 Electronic Flight Bags
An Electronic Flight Bag app being used in a general aviation aircraft
Computers have been ubiquitous in most work places since the mid 1990’s. A notable exception, until recently, is the commercial airliner flight deck. In the last 5 years, electronic flight bags (EFB’s) have become more and more commonplace. Before the FAA approved EFB’s, pilots would have to carry paper charts, approach plates, and aircraft manuals and checklists for each flight. This paper system was cumbersome, heavy, and took up the space of an extra suitcase. Now, tablets are taking the place of this system. In 2012, United Airlines provided their pilots with mounting hardware, and iPads for use in the cockpit.[9] Southwest and American Airlines followed suit.[10] Now, most major airline use EFB’s for their op- erations. This allows for more complex flight planning, greater precision and efficiency, and better organization. Airlines also save weight, as pilots no longer have to bring 45 pounds of paper with them on their flights. The use of a tablet brings the weight down to 1.5 pounds. Not only does this make the pilots life easier, but it also helps the airline save on jet fuel.[11] Future aircraft designs have tablet mounting and charging stations built into the flight deck, to make the integration of the system even more seamless.
6 CHAPTER 1. INTRODUCTION
Phablet (Samsung Galaxy Note II - 2012)
1.7 Portable Computers
Phablets, a portmanteau of “Phone” and “Tablet”, were first pioneered in 2007 by HTC. The concept was an original hybridization, borrowing the large, touchscreen display from a tablet computer and the functionality and size from a mobile cellular phone. The idea was eventu- ally adopted by other large manufacturers including LG (GW990) and Nokia (N810), and underwent several dif- ferent phases. The early generations had, in addition to a touchscreen, physical keyboards whereas the later ones do not. The Verizon Streak, produced and carried by the network, was released in 2009. Unlike most others at the time, it was restricted to phone and internet use within the household only. The current style of phablets was not popularized until 2011, after the launch of the Samsung Galaxy Note, (Android) which featured a 5.3” inch dis- play and a removable stylus.[12]
Laptop
Portable computers are compact and fully functioning versions of a regular desktop computer that are designed to be mobile. While they rely on rechargeable batter- ies or an electrical outlet for power, they allow a person the freedom to move around while still being productive. Their mobility alongside their ability to operate similar
to a desktop make them powerful tools for businessmen, students, and common individuals alike. Whether giv- ing or preparing a project or presentation, taking notes or studying online, or simply connecting to the internet from a cafe, portable computers have become essential for individuals who wish to work, study, or play on the go. Portable computers come in three basic versions which include the laptop, tablet, and netbook.
Tablet
Laptops are thin computers that contain a keyboard and monitor folded on top of each other so that the top half is the visual display and the bottom half is the input. Lap- tops are commonly called “notebooks” do to this fold- ing feature and their thin appearance. Recently, touch screens have been introduced into some laptops allow- ing some operating systems like Windows 8 to open ap- plications with the touch of a finger. While laptops are comparable to desktops in their use, their smaller size re- sults in some small amounts of the computing power and functionality being lost. However, their compact size al- lows them to be stored when not in use and the familiar “nest” of wires associated with linking up a desktop is reduced to a single power cord. Laptops are also bet- ter at “creating” fully functional content when compared to a Tablet or Mobile Device (such as a cell phone). If you require the ability to write reports or long e-mails, to use a spreadsheet in order to crunch numbers, to create a “PowerPoint” presentation, to rearrange music libraries or photo albums, or to edit pictures then you will need a desktop, laptop or a netbook. Tablets and Mobile Devices are more designed to consume content than to create.[13]
Tablets are smaller than laptop PCs, very lightweight, and extremely easy to carry, but they lack the processing power of a laptop as well as a keyboard input. They rely, instead, on a stylus and touch screen. For those who are hardcore gamers, giving business presentations, or con- ducting heavy research a tablet doesn't offer the speed and
1.9. WHAT IS A COMPUTER? 7
efficiency that is needed to complete these tasks. How- ever, if a person is more of a casual internet surfer or “lightweight” game player then a tablet can handle what computing is needed to do this. They can browse the web relatively easy and stream movies or Youtube videos too. It should also be noted that tablets have become handy for other lightweight tasks involved with simple music/DJ production like FX and mixing as well as live sequencing. Some artists and designers are now using their tablets for preliminary sketches that they transfer into design soft- ware and programs on a full powered laptop later on as well.[14]
Netbooks are similar to laptops but differ in size as well as processing. While netbooks are smaller versions of lap- tops, they have been designed, to the best of their ability, to have the same functionality as laptops and PCs. A net- book’s computer display will rarely reach above 10” or 12”, and are more commonly smaller than this, whereas some laptops can contain up to 15.5” of display screen. Netbooks have been around since 2008, roughly, and have revolved around their ability to connect to mobile networks such as the wifi at your local cafe or restaurant. Because of this feature, it has changed the laptop industry and has been heralded as a revolutionary and pivotal focal point in the production of laptops and netbooks. Since then this capability has now become a standard among both. Even though they don't maintain some of the func- tionality and computing power as their desktop and lap- top counterparts, they are still capable of word process- ing, mathematical computation, and other productivity programs that businessmen and students use. On top of that, they are also extremely durable and affordable which make them perfect for educational tools. Students will find them easy to manage, organize, and carry around as well as a “distraction free” resource because of their mini- malistic capabilities. Couple these advantages with inter- net access to mobile hotspots such as school libraries and it can be easily seen why this device had dominated the market for so long. It has only been a recent trend for individuals to pick up the tablet despite it’s rudimentary processing power and it has been speculated that this is due to the tablet’s sleek design and effective marketing strategy toward the younger generation.[15]
• Netbook
• Laptop vs. Netbook
1.8 References
[1] http://www.pixuffle.net/ the-importance-of-computers-in-our-daily-lives/
[2] http://www.wired.com/insights/2014/10/ smart-homes-of-the-future/
[3] http://www.blackboard.com
[4] http://everydaylife.globalpost.com/ should-computers-used-early-elementary-schools-3986. html
[5] Wikipedia: Timesheet
[6] http://office.microsoft.com/en-us/powerpoint/
[7] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013918
[8] http://www.pcmag.com/encyclopedia/term/47026/ midrange-computer
[9] []
[10] []
[11] []
[12] http://www.verizonwireless.com/mobile-living/ tech-smarts/what-is-a-phablet-verizon-samsung/
[13] http://www.pcmag.com/article2/0,2817,2364302,00.asp
[14] http://www.lenovo.com/us/en/faqs/laptop-vs-tablet/
[15] http://www.lenovo.com/us/en/faqs/what-is-a-netbook/ #eventbody1
1.9 What is a Computer?
1.9.1 Data vs. Information
Information Relationship Model
Data are calculated and processed on a daily basis through computers in business, at home, and in education. Data are essentially the raw facts that are usually typed into a computer. We call these “raw” facts due to them being unorganized. They can come in any form from audio and visual, to text and numerical. When the data is entered into the computer, that is considered input. The computer
8 CHAPTER 1. INTRODUCTION
Represented Data
calculates the data and spits out the information. Since this information is the output, it becomes the organized version of what used to be raw facts. This system is con- sidered information processing. Data can also come in other forms including figures, experiments, and surveys. Most everything that is entered into a computer becomes data, which is why this term is so vital to understanding computers and how they operate. [1] Information is pro- duced by the data; it is form of knowledge, and computers calculate detailed information. [2]
When most people think of information, the first source that comes to mind is Google. Google allows you to ac- cess a lot of information in a short amount of time. What most do not know is that is exactly what a computer does behind the scenes every time you are entering data into a computer, most of the time without even considering it to be “data.” Information is a way to get answers to ques- tions, because they are the output of the data you have put in to process. Many online sources provide endless amounts of information. Without information, people will not have reliable sources for school and their career. Work can be made much easier with information, includ- ing jobs which need to calculate employee’s total hours worked, or any “total data” that needs to be found or cal- culated. Data and information are very valuable, and is most certainly the backbone of a computer. These two components may help your computer to be user-friendly by working behind what you are typing to make data use- ful and organized. [3]
1.9.2 Computers Then and Now
It is difficult for a college student to imagine life without a computer. However, computers have only been around since the mid 1900’s. The computer industry went from making computers that took up an entire classroom to currently being able to fit into a student’s backpack. Also, computers used to be much more expensive and required a greater amount of energy than today’s computers. Fi- nally, in the 1980s, people began placing these foreign objects into their home. During this time, people had to really study and be patient with this handy device. [4] Peo-
Computer from the 1980s
ple have seen the drastic changes that have been made to computers in a span of only forty years. Computers to- day are much smaller, lighter, require less energy, and cheaper. However, in today’s generation, computers are second nature to most people, and one could not imagine life without them.
An open computer case displaying the hardware.
Computers in our generation seem to be integrated in our every day life to assist in multiple tasks related to our many needs. So much so, it is difficult to picture our world without them. However, with great success comes great patience. In the first computer model (1946- 1957) for example, the machine required certain inputs, referred to as punch cards, and physical work to repro- gram the computer. The computer itself was nowhere near as helpful, simple, nor convenient as it is today. The first generation computers were built with thousands of vacuum tubes, required physical effort to re-wire the computer, and could only solve one problem at a time. The second generation of computers (1958-1963) in- troduced transistors, which replaced the vacuum tubes. Transistors simply acted as a light switch, allowing the electronic circuits to either open or close. Both first generation computers, and second generation comput- ers continued to use punch cards for their input. Sec-
1.9. WHAT IS A COMPUTER? 9
ond generation computers also introduced hard drives (hardware), and programming languages (FORTAN & COBOL). Soon after, (1964-1970), the third generation used a system of integrated circuits, which incorporated many transistors and electronic circuits on a single sili- con chip. The third generation of computers started the innovative trend of smaller and more reliable comput- ers. Keyboards and monitors were now considered the computer’s input/output. Finally, the development of our current computers, used by practically everyone in soci- ety, began. The fourth generation of computers began in 1971, when it was possible to place far more transis- tors onto a single chip- the microprocessor. This discov- ery led within the decade to the creation of IBM’s per- sonal computers, as well as the popular Apple Macintosh. Consumers currently use inputs, outputs, and storage that consist of: keyboards, mice, monitors, printers, speakers, hard drives, flash memory media, and optical disks. Although the movement from vacuum tubes to micropro- cessors seemed to take a while, compared to the begin- ning of civilization thousands of years ago, this advance- ment happened very quickly. However, it also opens the human mind to realize that innovation takes trial, error, and patience. [5]
1.9.3 Hardware
The term hardware refers to the components used to build a computer. Breaking down the components into cate- gories, you will find five main groups:
1. Input
2. Output
3. Memory
4. CPU
5. Communications Hardware
Although these are the five main categories, there are three more components to consider that do not fit into those main four:
1. Case
2. Power Supply
3. Expansion Cards
Case
A computer case is used to put the essential components of a computer in. This provides an enclosed space and easier organization for the components to go.
Power Supply
A power supply unit (PSU) is used to power all com- ponents inside the case. It does this by converting AC power to DC power that is regulated by the PSU. What this means is that each component needs a certain amount of volts to work and the power supply will regulate the volts accordingly.
Expansion Cards
An expansion card is used to enhance certain attributes of the system. For example, a sound card can enhance sound by giving you surround sound capability. Another example is a video card, this will enhance the graphics of your system.
• Sound Card
• Video Card
Input/Output
This category refers to the components a computer uses that receive data and send information. Input devices do the receiving and the output devices do the sending. Some examples of input devices are a keyboard, mouse, and a gaming controller. Examples of output devices are a printer, monitor, and speakers.
• Keyboard
• Mouse
• Controller
• Printer
• Monitor
• Speakers
Memory
The memory within a computer can be broken down into two categories: short term memory and long term mem- ory. Short term memory is the random access mem- ory (RAM) while the long term is either your hard disk drive (HDD) or compact disk drive (CDD). RAM can be tapped into immediately by programs on a computer al- lowing it to compute faster, but if the user needs to save information for later use, using the HDD or CDD is re- quired.
• RAM
• HDD
• CDD
10 CHAPTER 1. INTRODUCTION
CPU
The central processing unit (CPU) is used to calculate the commands sent to it by the programs used on the system. It performs all the arithmetic and logical operations. This comes in the form of a small chip that is connected into the computer motherboard. The motherboard is where all other devices are connected so they can speak with each other.
• CPU Chip
• Motherboard
Communications Hardware
An example of a wireless router.
Communications hardware is important when it comes to letting computer users access information from the In- ternet, put information onto the Internet, or interact with other computer users on a network. This type of hard- ware includes modems, routers, and network adapters. Modems and routers are the devices that connect com- puter users to the Internet: Signals go from the Inter- net service provider to the modem, which then converts them into an appropriate form and sends them through the router to the computer (or, when the computer user is sending information to the Internet, signals are sent via the router to the modem, which converts them and sends them to the Internet service provider.)[6] Modems and routers can be either wired or, increasingly commonly, wireless, communicating with the computer via signals rather than a physical connection. Network adapters are what allow computers to communicate on a small, local network. Sometimes, however, a computer may have a network adapter that consists entirely of software, called a virtual adapter. If this is in use, such as on a virtual private network (VPN), then no hardware component is needed.[7]
Operating System
User
Application
Hardware
Diagram displaying how software communicates with the user.
1.9.4 Software
Computer software is used to communicate with the com- puter processor to direct certain operations to be per- formed. This is done through computer programming languages. Software can be broken into two parts: Sys- tem Software and Application Software.
System Software
System software refers to the software used to operate the computer components. This also provides a founda- tion for application software, giving it the ability to carry out the desired functions. System software commonly comes on a system CD, for example a Windows 7 CD. This CD provides the operating system, drivers, Windows system, and utility software. The operating system allows the parts of the computer to communicate. This is done by transferring data. This is also the specific component of system software that allows for the running of appli- cation software. Utility software maintain the computer systems. Device drivers set up the ability for the hard- ware connected to the computer to function. Windows systems is the part that gives you a graphical interface on your monitor and allows the user to configure all con- nected devices.
• BIOS Menu
1.10. COMPUTERS TO FIT EVERY NEED 11
Application Software
Application software are the programs and applications that are developed to carry out desired functions by the user. The way an application works is through program- ming software. Programming software is the middle man between the system and the actual application the user wants to run. Some examples of programming languages are Java, C++, and Visual Basic. Some examples of ap- plication software are web browsers and video games.
• Repeat loop for Mint
• Firefox logo
Two gentlemen discussing programming ideas.
1.9.5 Computer Users and Professionals
Computers are nothing without the people that use them, the common user and the professional. The common user is anyone that uses the computer for general purposes. This includes checking emails, playing computer games, typing up a paper, and the list goes on. What distinguishes a common user from a professional is that a professional works in the field of computer information technology. Examples of professions in this field are a computer pro- grammer, web designer, network administrator, and soft- ware engineer. These are but a few of the many jobs in- volved in the field of computer information technology. These are the people that design the hardware to build computers, they keep business networks secure, they pro- gram software to communicate effectively with the user and hardware, and develop the latest and greatest software for the common user to enjoy.
1.9.6 References
[1] http://otec.uoregon.edu/data-wisdom.htm
[2] http://www.huridocs.org/information-systems/
[3] Understanding Computer Today and Tomorrow 14th Edi- tion Comprehensive
[4] http://www.youngzine.org/article-u-write/ first-computers
[5] Understanding Computer Today and Tomorrow 14th Edi- tion Comprehensive
[6] http://www.pcmag.com/encyclopedia/term/63628/ modem-vs-router
[7] http://compnetworking.about.com/od/ hardwarenetworkgear/a/networkadapter.htm
1.10 Computers to Fit Every Need
1.11 Phablets
Phablets, a portmanteau of “Phone” and “Tablet”, were first pioneered in 2007 by HTC. The concept was an original hybridization, borrowing the large, touchscreen display from a tablet computer and the functionality and size from a mobile cellular phone. The idea was eventu- ally adopted by other large manufacturers including LG (GW990) and Nokia (N810), and underwent several dif- ferent phases. The early generations had, in addition to a touchscreen, physical keyboards whereas the later ones do not. The Verizon Streak, produced and carried by the network, was released in 2009. Unlike most others at the time, it was restricted to phone and internet use within the household only. The current style of phablets was not popularized until 2011, after the launch of the Samsung Galaxy Note, (Android) which featured a 5.3” inch dis- play and a removable stylus.[1]
Samsung Galaxy Note series (blank screens)
1.11.1 Embedded Computers
An embedded computer is a mini computer with a spe- cific function within a product that completes detailed tasks or jobs for that product. Often times, individuals
12 CHAPTER 1. INTRODUCTION
Thermostat Embedded Computer
Embedded Computers were used in the Apollo Guidance Com- puter
do not realize how many objects have embedded com- puters enclosed in them. Some examples of embedded computers used in households include, remote controls, heating pads, digital clocks, washing machines, and mi- crowaves. Others include Bluetooth capabilities in cars, camera traffic lights, and Red Box machines. Surpris- ingly, a pregnancy test is also considered a simple, yet complicated embedded computer.[2] Embedded comput- ers are developed to do one particular duty, and therefore a regular computer cannot act as an embedded computer. So how does an embedded computer work? To put it into simple terms, an embedded computer is a computing chip rooted directly onto its motherboard or logic board. Before embedded computers were invented, a comput- ing chip would be connected via wires to the mother- board, which would then be connected via more wires to the RAM and other peripherals. This not only made the interior of any computing device look like an abso-
lute mess, but it was incredibly inefficient and perfor- mance was never what it could have been given the ca- pacities of the components involved. With the advent of “embedded” or “integrated” components, the interior is free of all these transferring wires, and data only needs to bridge a small gap, rather than travel through tons of cables. The advantages of the embedded computers are that the bussing speed for data has greatly improved over externally transported components due to the minimal amount of physical distance data needs to travel.[3] To- day, there are specialized jobs just for programming em- bedded computers.[4] The first embedded system used was the Apollo Guidance Computer created by Charles Stark Draper. It was considered to be one of the highest risks in the Apollo project since it was newly developed, but since then it has been proven to be more efficient.[5] Embedding computer technology has continued to de- velop and the “gaps” that needed to be covered have be- come smaller and smaller. A great example of this is the cell phone, which has evolved from the first “portable” bag phones into today’s iPhone5s that can fit in the palm of one’s hand. These embedded computer systems are used in all areas of life, and can be found anywhere from cooking and consumer functions to medical and military tasks.[6]
1.11.2 Mobile Devices
Smartphone Mobile Device
A mobile device is a handheld tablet or other device that is made for portability, and is therefore both com- pact and lightweight. New data storage, processing and display technologies have allowed these small devices to do nearly anything that had previously been traditionally done with larger personal computers.[7] These mobile de- vices are capable of numerous tasks including making phone calls, sending text messages, viewing Web pages, playing games, downloading music, taking digital pho- tos, and watching TV shows and movies. With our ever- growing world of technology, mobile devices are at the tips of our fingers. Questions can be answered, maps can be observed, and weather can be checked. Of the many mobile devices used today, smartphones are the most common form of device. They have Internet ca-
1.11. PHABLETS 13
pabilities along with the extensive list above. Tablet de- vices do not have all the capabilities smartphones have, but they are used for Web browsing, gaming, taking digi- tal photos, and playing movies as well as TV shows. Mo- bile devices are now a big part of people’s everyday lives. Google stated, “The mobile phone might be the world’s most ubiquitous device…” (www.thinkwithgoogle.com/ insights/uploads/940910.pdf/download/) . This shows how technology will keep improving, to become the some of the most widely used devices around. One of the drawbacks to some of the newer mobile de- vices is their use of non removable batteries. These bat- teries are designed to make the device more light weight. Although they are made to last for the duration of the computers life, there are instances when they fail. If this happens, it can be pricy and difficult for them to be re- placed. Because of this, it is not uncommon for a user to simply throw the device away rather than spend the time or money to fix it. This has resulted in a big in- crease in what is known as e-trash, or electronic trash. Adding to this problem is the fact that these devices of- ten contain toxic and harmful chemicals and eventually end up in landfills that are not able to dispose of them properly. Much of these devices make their way to coun- tries with less standards and regulations for waste man- agement, giving way to environmentally unfriendly and dangerous practices. This leads to toxic and lethal chemi- cals entering the air and water. Certain organizations such as Clean Production Action and Greenpeace have devel- oped programs to attempt to persuade manufactures to stop using hazardous chemicals in their products. Unfor- tunately it may already be too late to reverse the damages done from e-waste. It is essential for the well being of this planet that mobile devices and other computer equipment are disposed of properly.[8]
1.11.3 Personal Computers
A personal computer is a computer that is mainly for indi- vidual use. Before personal computers, computers were designed for companies who would then attach terminals that would allow for more than one user to a single large computer and the resources were shared among all users. The first personal computers came out around the 1970s. The most popular of the time was the Apple II, which came out in 1977 from Apple Computer. In 1981, IBM came out with its first personal computer. IBM PC took over the market and it was what most people bought. Per- sonal computers use single-user systems and are based on microprocessors.[9] Many people do link their per- sonal computers together to create a network. Most per- sonal computers are made up of a central processing unit, control circuitry on an integrated circuit, and various in- put/output devices. It also contains two types of memory; main memory and auxiliary memory. The sales of per- sonal computers has grown tremendously over the years, according to Michael Dell in 2005 there were 240 mil-
Laptop- Personal Computer
lion personal computers sold worldwide.[10] The sale of personal computers will, likely, continue to increase.
1.11.4 Midrange Servers
Ultra Enterprise 4000, rear
School computer lab using a midrange server
Midrange servers were also known as midrange comput- ers or minicomputers in 1960s and were mostly sold to
14 CHAPTER 1. INTRODUCTION
small and medium-sized businesses. However, midrange servers started to become popular in the 1990s. Midrange servers are used to host data and programs for networks, such as in hospitals or school computer labs. Midrange servers stand in between entry-level servers and main- frame computers. The big difference between midrange servers and mainframe computers is that the midrange servers function as stand-alone personal computers where mainframes are a network hosts. Midrange servers tend to have more memory capacity, such as random ac- cess memory (RAM), processing power (have multi- ple processors), room for expansion (have comparably large hard drives), and are more expensive than desk- top computers.[11] Midrange servers are not limited for business use only. Another type of midrange servers is a special home server that can be build or purchase when personal computer is not enough. Special home server links all the content from all the computers onto one network.[12] Moreover, something that is happen- ing more frequently with midrange servers is called vir- tualization. It involves splitting hard drives and creat- ing two separate hard drives. It can also involve server virtualization which is splitting the physical server into smaller virtual servers. Each virtual server can run mul- tiple operating system requests at the same time. Virtu- alizing servers is the best solution for small and medium- scale applications.[13] Virtualization helps companies to use fewer servers and that leads them to reduced costs and less server management.[14]
1.11.5 Mainframe Computers
Early mainframe computer
Mainframe Computers are much larger computers that consolidate the needs of large organizations like univer- sities, hospitals, banks, government offices, etc. These much more powerful and expensive computers are usu- ally stored in data centers where they connect to all the other computers using a computer network. From this room a single mainframe can serve thousands of users on the same network. Early mainframe computers were
M ai
nf ra
m e
Mainframe Computer
first produced in the 1950s due to the increasing pro- cessing demands of growing businesses. From then on, these mainframes have increased in power and improved in size.[15] However, with more processing power, this re- quires more energy consumption, leading computer man- ufacturers to focus more on energy efficiency in these new computers. Manufacturers also began bundling free software with their mainframe computers as an incen- tive to help compete against other computer manufactur- ers. Eventually, a lot of these programs and several new ones were offered as separate products that they could sell rather than just giving them away for free.[16] Today, mainframe manufacturers use advances in technology to further improve the power and efficiency of their com- puters, one important being virtualization, creating sev- eral virtual servers rather than physical ones that take up space. Mainframe computers may be good for having one space to collect data for a company. They are also known as high end servers, or enterprise class servers. The main- frame computer at IBM has 100,000 virtual servers and is actually very economically efficient , and more and more of businesses are trying to make them the most energy efficient as possible [17] The mainframe computers need a large enough space to be located for one, since they are used for large business responsibilities, such as comput- ing data for a census, statistics, and economic processing. They are also used for payroll and billing but are con- stantly running day and night with different tasks to com- plete all the time. The type of tasks this computer does allow for them to operate for a long time with no inter- ruptions. Mainframe computers are also very expensive. Having to find a way to cool a mainframe computer is dif- ficult just because of their size alone. The other problem
1.12. COMPUTER NETWORKS AND THE INTERNET 15
with the computers is that they are also expensive to even run, again because of their size. The amount of electricity to cool and run the mainframe computers makes them not the most energy efficient machine to have in a business.
1.11.6 References [1] http://www.verizonwireless.com/mobile-living/
tech-smarts/what-is-a-phablet-verizon-samsung/
[2] http://www.pcmag.com/article2/0,2817,2379383,00.asp
[3] Understanding Computer Today and Tomorrow 14th Edi- tion Comprehensive
[4] http://searchenterpriselinux.techtarget.com/definition/ embedded-system
[5] https://en.wikipedia.org/wiki/Embedded_system
[6] https://en.wikipedia.org/wiki/Embedded_system
[7] http://www.techopedia.com/definition/23586/ mobile-device
[8] Understanding Computer Today and Tomorrow 14th Edi- tion Comprehensive
[9] http://www.webopedia.com/TERM/P/personal_ computer.html
[10] http://whatis.techtarget.com/definition/ personal-computer-PC
[11] http://www.wisegeek.com/ what-is-a-midrange-computer.htm
[12] http://www.techopedia.com/definition/14471/midrange
[13] http://www.techopedia.com/definition/719/ virtualization
[14] http://searchservervirtualization.techtarget.com/ definition/virtualization
[15] http://www.computerhistory.org/revolution/ mainframe-computers/7/172
[16] http://www.computerhistory.org/revolution/ mainframe-computers/7/172
[17] http://www.princeton.edu/~{}achaney/tmve/wiki100k/ docs/Mainframe_computer.html
1.12 Computer Networks and the Internet
1.12.1 The History of the Internet
The history of the internet begins in 1962 with J.C.R. Licklider’s memos about an Intergalactic Network idea, in which users around the world are connected and can access programs and data. With colleagues, he forms
a research program called Information Processing Tech- niques Office (IPTO). After an experiment with an air travel reservation system, the first communication satel- lite is launched that can allow machines to exchange data. Soon, IBM introduces System 360 computers into the market which becomes remarkably popular. American Airlines debuts IBM’s SABRE air travel reservation sys- tem to process on-line transactions, which links over 50 cities through telephone lines (1964).
Original Macintosh Computer
[1] By 1965 the first wide-area network connection is es- tablished by Larry Roberts and Thomas Marill. Over the next four years, the Network Working Group works diligently, creating a router, a modem, and even exper- imenting with monitors. On October 29, 1969 the first host-to-host connection was made! Then, over 3 years, memory, speed, processing, and communication capabil- ities are tested and refined and protocols are made. By 1973, 30 institutions are connected to the network called ARPANET.[2] In 1977 Steve Jobs and Steve Wozniak an- nounce the Apple II computer, opening the consumer and small business market for computers. This led to the cre- ation of more modems for dial up services. A computer science research network called USENET sets up a server where newsgroups can post to, in 1979. A year later an email only service opens. Less than a decade later, 30,000 networks are on the internet due to the advances with computers, including the new Macintosh computer and the use of Ethernet. [3] Within 2 years the number of hosts jumps to over 160,000! By 1991 over 600,000 hosts are connected in over 100 countries! [4] In just 30 years the hypothetical concept J.C.R. Licklider once toyed with has become a part of everyday life! A lot of experimenting and funding went into the creation of this remarkable “cyberspace.”
1.12.2 From ISP to URL
Now that you know the history of how the internet came to be, it’s time to start exploring. You double-click your
16 CHAPTER 1. INTRODUCTION
Domain names are like fingerprints; no two are alike.
browser of choice, the screen opens up... and you start drawing blanks. 'Where do I go from here?' you might start asking yourself. Just take a deep breath; using the internet isn't as complicated as you might think. The most important thing to understand before you start browsing through the cornucopia of online resources is the URL, (Uniform Resource Locator.) The URL uniquely iden- tifies a specific Web page. The URL is composed of a communication protocol, (typically HTTP or HTTPS,) a domain, and a page. If you want to have your own web- site, you have to buy the domain name and then build upon your address. [5] The most interesting tidbit about domain names is that, just like fingerprints, no two can ever be the same. Unfortunately, this means you can't ever own the domain name www.apetit.com.
1.12.3 Internet Communication
In today’s technologically booming society, there are hun- dreds of ways we are connected to computers and the Internet every day. We use computer networks (col- lections of computers and other devices that are con- nected together to enable users to share multiple forms of information)[6] on a daily basis. While it is not al- ways free to do so, such as having to pay an Internet ser- vice provider (ISP), there are many places that offer free wifi to people in their area. Today, we mostly use net- works for social media, communication, and spreading of information. Think of the networks in your life. I'm guessing something like Facebook, Twitter, Instagram, or LinkedIn came to mind along with many others[7]. These are all networks that allow us to share informa-
Email icon
tion whether it be personal, images, news stories, surveys, information on new products, etc., these networks have become engrained into our daily lives and most people see them as helpful devices for distance communication and spreading of ideas. Another way we use the Internet for communication is through email. Most people today have an email address because they are required for reg- istration for many different things we use on a daily basis (such as the networks previously listed)[8]. Usernames for e-mails have to be unique to ensure that every person in the world that wants to be on the Internet can have e- mail. E-mails consist of a username (something to iden- tify it specifically), followed by the @ symbol, and finally a domain name like “yahoo”, “gmail”, and many others. Many usernames just incorporate a person’s name, but you can also use periods, underscores, numbers and other symbols to make it unique. In the past, blank spaces were not allowed in a username but some companies do allow
1.12. COMPUTER NETWORKS AND THE INTERNET 17
it now. One symbol that is still not allowed in a user- name is the @ symbol, because it could be confused with the same symbol that separates the username and domain name. An example of this is Drupal. It is each company’s responsibility to make sure that each username attached to their domain name is unique. Today’s evolving tech- nology is making it easier to access things like networks and email through all of the mobile devices available and the use of apps or condensed mobile versions of the full desktop websites. Besides the obvious social uses of e- mail communication, they are now being used to help col- lege campuses communicate with their students to help alert the students of an emergency like a tornado, dan- gerous lightning storm, flood warning, or if an intruder is on the campus. E-mail has become a great communi- cation highway for coworkers in businesses and just for casual friends. All in all, the Internet and computer have changed our world in forms of communication. [9] [10]
1.12.4 Searching the Internet
The internet’s top search engines.
Searching the internet for a specific page or phrase has be- come easier than ever through the help of online search engines. Certain webpages, most popularly Google, have specific programs and algorithms that sort through the vast expanse of information available on the web. These websites work by processing keywords that are typed into the search bar and displaying a large list of webpages matching the keywords. Even in the early days of the in- ternet there were programs such as “Gopher” that could help search the net, although the scale of these searches has risen exponentially since then. [11] Using special pro- grams called “spiders”, the search engine compiles a list of results by crawling through the internet starting with the most popular websites and servers for the keywords searched. Through these processes an index is created by the spiders that is constantly being updated regarding
the most popular and relevant results of all searches be- ing completed, which on Google is over 3.5 billion per day and 1.2 trillion per year [12]. The more that people use these search engines, the faster and more efficient they become. Other websites may search for more spe- cific information on webpages such as phone numbers, addresses, and maps. The websites where this informa- tion is kept are called reference pages.
1.12.5 TCP/IP
Schema internet
Application Layer
TCP/IP - Transmission Control Protocol/Internet Proto- col –the most prevalent protocol stack used to connect hosts o the network and networks to each other. The suite of communication protocols has been developed due the request of the Department of Defense as a protocol of an interconnection the experimental “ARPANET” and di- verse computing networks. A great contribution to the development of TCP / IP stack has made by the Uni- versity of Berkeley, implementing protocols stack in its version of OS UNIX which has led to widespread IP pro-
18 CHAPTER 1. INTRODUCTION
tocol. Moreover, the Internet, the biggest global infor- mation network, runs on TCP/IP suite and Internet En- gineering Task Force (IETF) is a major contributor to the improvement of the standards of the stack, published in the form of specification RFC. Since the TCP / IP stack was designed before the OSI – Open System In- terconnection, his 4 layered structure also corresponds to 7 layered OSI model is rather arbitrary. The lowest (level 4) corresponds to the physical and data link layer model OSI. This level in the TCP / IP protocols is not regulated, but it supports all popular standards of physical and data link layer both LAN (Ethernet, Token Ring, FDDI, Fast Ethernet, 100VG-AnyLAN0 and WAN - communication protocols, (“Point to Point” SLIP, PPP X.25, Frame Re- lay). The next level (level 3) - is the level of interconnec- tion, which is engaged in the transmission of packets us- ing a variety of transport technologies of local networks, regional networks, special communication lines, and so on. As the main network layer protocol (in terms of the model OSI) IP, which was originally designed to trans- mit packets through the many numbers of networks, com- bined both local and global protocols. Therefore, the IP protocol works well in networks with complex topologies using rationally presence of subsystems and economically consuming bandwidth low-speed communication lines. The IP protocol is a datagram protocol, which means it does not guarantee delivery of packets to the destination node, but trying to do it. Besides the IP protocol, inter- net layer is represented by some other protocols such as RIP (Routing Internet Protocol), OSPF (Open Shortest Path First) and ICMP (Internet Control Message Proto- col). The last protocol is designed to share information about errors between routers and network node. Level 2 is called the primary. This level is a field of a func- tioning TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). TCP provides the guaranteed delivering of the information and usually is being used by applications if data integrity and accuracy are critical. The UDP is being used for a non-guaranteed transmit- ting. The upper level 1 is the application level. Over the years, TCP / IP stack has accumulated a large number of protocols and application-level services. These include such widely used protocols as protocol to copy files FTP, TFTP, telnet, SMTP, HTTP, DNS and etc. [13]
1.12.6 References [1] http://www.computerhistory.org/internet_history/
[2] http://www.computerhistory.org/internet_history/ internet_history_70s.html
[3] http://www.computerhistory.org/internet_history/ internet_history_80s.html
[4] http://www.computerhistory.org/internet_history/ internet_history_90s.html
[5] https://www.nationalserviceresources.org/ understanding%20-urls-and-domain%20-names
[6] http://www.techopedia.com/definition/25597/ computer-network
[7] http://socialmediatoday.com/soravjain/195917/ 40-most-popular-social-networking-sites-world
[8] http://www.email-brokers.com/en/ emailing-business-strategy
[9] https://www.drupal.org/node/56487
[10] http://dmv.ny.gov/transaction-message/ information-about-email-addresses
[11] http://computer.howstuffworks.com/internet/basics/ search-engine1.htm
[12] http://www.internetlivestats.com/ google-search-statistics/
[13] http://www.w3schools.com/website/web_tcpip.asp
1.13 Computers and Society
1.13.1 Benefits of a Computer-Oriented Society
Benefits
Our generation strives to be the quick paced society which we are known to be. To do so, our generation uses com- puters to their full potential in order to do more tasks and to do them at a faster pace. Computers benefit the busi- ness and personal world by being able to do the follow- ing more efficiently: buying and selling products, com- munication throughout the world, enhancing our knowl- edge, job influences, entertainment, research and pay bills. We’re now capable of creating new, more and bet- ter quality tasks with the enhancement of our technol- ogy. It also benefits the society with the enhancement of knowledge of medicine which creates more effective treatments, being able to create a better and longer life (which is another way to be more efficient). From my personal benefits of having a computer, I am able to have this blended course in able to invest my time differently so I will be able to do more tasks at the time a normal class would meet. The conveyance of computers is that
1.13. COMPUTERS AND SOCIETY 19
you are able to access the computer 24 hours a day, 7 days a week, and 365 days a year. This gives our soci- ety the time to expand their knowledge and create new opportunities for themselves whenever it’s needed. [1]
The Hit Sci-Fi film of 2009, Avatar, used photorealistic computer-generated characters, created using new motion- capture animation
Being a very crucial part of the human race, comput- ers have ultimately altered the way today’s society works, communicates, entertains, and educates. There is hardly any field of career left where technology isn’t essential; every small action performed in a job ultimately goes through some kind of a computer. In the end, being able to communicate and engage in this fast-paced manner en- hances productivity level by a great amount. One area this advancement of computers has immensely impacted is the business field. All businesses use computers to keep track of accounts, money, or make transactions. No longer will it take days, or even weeks, to communicate with someone that might not be located in one’s vicin- ity, as a computer allows one to easily send and receive emails with just a click of a button. Another field that has come a long way ever since the production of com- puters is the entertainment area. Without the exceptional special effects put into an action movie with the help of our advanced technology, the audience would most likely not enjoy the show, resulting in the potential collapse of the entertainment business. For example, imagine watch- ing the epic science fiction film, Avatar, but without any special effects put into it…it certainly would not be as en- tertaining as the power of computers transformed it to be. Hence, computers are able to keep both such consumers and sellers satisfied, while still continuing to integrate into the everyday lives of average individuals. [2]
1.13.2 Disadvantages of a Computer- Oriented Society
With any benefits, there comes a disadvantage. As for computers, there have been problems with an excessive use, security and privacy issues and the problem with a dominant culture. With any product, any excessive use is bad; in this case the excessive use of the computer may
Disadvantages
result to a lack of human communication for face to face conversation and more communication through the com- puter. This affects our society’s confidence for when they are in in-personal conversation. To further add, people have the accessibility to abuse their time whereas people tend to be more attentive to their internet accesses and making the computer a time-consuming product. Many of the security and privacy concerns stem from the fact that a lot of our personal business takes place online. One example of a security risk today is malware. Malware can be accidentally installed onto your computer by clicking on a link on a Web page or e-mail message that contains a malware program, such as a computer virus. Once a malware program is successfully installed, it will typically erase data or bog down the computer, but it can also a steal sensitive data from the computer such as passwords or credit card numbers. To fight against malware, a wide variety of security softwares can be installed which will notify and block any attempts of malware trying to gain access to a computer. Another very common security risk is identity theft. Identity theft is when someone else gains access to your personal information and uses your identity to purchase goods or services. A popular way for identity thieves to steal personal information is phishing, a fraud- ulent e-mail or website that appears like a legitimate busi- ness in order to obtain Social Security numbers or other information needed for identity theft. The last idea on how it influences our society is that there this dominant culture crisis that the cultures, globally, compete one an- other on the latest technology enhancement which creates a stronger ethnocentrism to the countries. As computers become more accessible and creates new ways to be more effective, it comes with more accessibility to these disad- vantage and/or create new ones.[3]
20 CHAPTER 1. INTRODUCTION
1.13.3 Differences in Online Communica- tions
It is obvious that, as the computer has evolved, our com- munication processes through it have as well. Emails and social networks have quickly become the telephone of the past; these tools are not only used in the personal world, but in the business world as well. However, though com- puters make it easy and drastically more convenient to communicate with people, it is important to follow a few simple guidelines and watch the tone while talking. These guidelines have come to be known as netiquette. Neti- quette simply establishes what is and what is not accept- able when involved in online communications. One needs to remember that though it may not be face-to-face, they are still interacting with a human being. Act kind, courte- ously, professionally, and respectfully. Be sure to adjust your spelling, grammar, and tone of voice depending on the situation you are in; it may be okay to be casual when in a personal conversation, but emoticons and abbrevia- tions don’t look to impressive within the business world. By following the rules of this accepted Internet law, it is easy to make oneself look rational, well educated, and insightful.[4]
1.13.4 The Anonymity Factor
It is an inevitable fact that, with increasing online com- munications, there is almost always going to be a sense of anonymity. Like almost anything in the world, this can be used for both good and bad purposes. Online, one can be who they want to be. They can have a secret identity, they can make unknown usernames, and they can say the things they want without feeling the judgment of others upon them. This can be used for good if it is for true, honest, and legitimate opinions. Examples of this are re- views, discussions, blogs, and important emails. The free- dom of being a faceless commentator makes the individ- ual feel comfortable expressing how they truly feel. How- ever, it is important not to abuse this anonymity. People often use it to insult, harm, or coerce others into fraud. It
blogging
Anonymous
is central that one learns how to properly and respectfully use this gift of obscurity without abusing it.[5]
Diving deeper into the aspect of anonymity on the Inter- net, we see the need for anonymity and accountability. Users need to be anonymous in regards to personal infor- mation, such as, credit card information but need to be ac- countable for what they say online. Accountability means that anyone that partakes in misconduct online will be identified and be responsible for the consequences. David Davenport, an assistant professor in the Computer Engi- neering department at Bilkent University, explains that allowing anonymous communication online ensures that users of the Internet become unaccountable for what they say. He believes that free speech is not hindered if users are identifiable online. One reason for anonymity is the need for information privacy, which refers to the rights of individuals and companies to control how informa- tion about them is collected and used. If everyone online could see the credit card number or the physical address of individual Internet users then no one would be safe. Professor Davenport explains the need for anonymity in protecting personal information and for accountability in identify users that partake in criminal acts online. Per- haps, in the future, as technology improves and is in-
1.14. REFERENCES 21
creasingly able to identity persons of malicious intent then anonymity will not be such a concern.[6]
1.13.5 Integrity Factor
Question everything.
Due to the relative ease of accessing virtually any sort of information on the internet, every user will encounter the scenario of verifying the credibility of that piece of information. It is estimated that there are over 200 bil- lion web pages, yet search engines cover less than a quar- ter of that figure. This leads to the fact that the internet is bound to provide both accurate and inaccurate infor- mation, which therefore places the responsibility of val- idating what was found on the user. For example, be- cause Wikipedia provides such an extensive database of human knowledge freely and the ability for any person to edit many of the articles, it became apparent early on that there was a sort of “vandalism” taking place. Users would purposefully make false claims relating to that article for entertainment, and this constant abuse of the system in- evitably led to a somewhat damaged reputation for the re- liability of the site. However, over the years, Wikipedia has improved itself with updated methods of deterring vandalism to provide for more accurate information. Wikipedia is only one site of billions, though. To ob- tain reliable information means for a user of the inter- net to question literally every site. According to Virginia Tech, this “questioning” is composed of five fundamen- tal aspects: authority, coverage, objectivity, accuracy, and currency. Authority relates directly to the source of the information on that page. A user must take into consid- eration who is creating the information and the associ-
ations of the author(s) to other persons or groups (e.g. URL, reputation, expertise). Next, coverage questions the depth of the relevant information. This requires the user to examine the page and determine whether the in- formation is actually useful or not. Objectivity is another crucial component because it examines inherent bias that authors use to further their goals. The information must be factual instead of distorted to persuade the user into taking a side. Accuracy is arguably the most important because it tests the validity of the information. For ex- ample, if the page contains a claim that completely con- tradicts the scientific community, it might be good reason to determine that everything else be read with a skeptical mindset. Lastly, currency examines how up-to-date the page is compared to the present time. If there are multi- ple updates frequently with links that are still alive (that is, they do not redirect the user to a dead page) then the user can feel confident that the author is providing infor- mation that is relevant to today.[7]
1.14 References [1] http://riogietoledo.blogspot.com/2012/03/
nowadaysour-society-depends-on.html
[2] http://www.insidetechnology360.com/index.php/ how-computers-benefit-society-6-30949/
[3] http://www.studymode.com/subjects/ benefits-of-computer-oriented-society-page2.html
[4] http://www.albion.com/netiquette/corerules.html
[5] http://people.dsv.su.se/~{}jpalme/society/anonymity. html
[6] http://www.csl.mtu.edu/cs6461/www/Reading/ Davenport02.pdf
[7] http://www.lib.vt.edu/instruct/evaluate/
1.15 Review
1.15.1 Key Terms
Application software Application software is all of the programs on a computer that to e specific task. i.e. playing video games, or typing a paper.[1]
Boot Booting up a computer is the process where you first turn it on after a time where the computer is off. The computer does a system check to ensure everything is operational between the OS, Bios, and hardware.[2]
Computer A computer is any electronic device that is programmable, accepts input, processes that data, and produces an output.[3]
22 CHAPTER 1. INTRODUCTION
Domain name A domain name is a text based name that is unique to each computer on the internet.[4]
Email Email or electronic mail is a digital message sent from one user to another through a network or the internet.[5]
Embedded computer An embedded computer is a small computing device that does a specific function for that device.[6]
Hardware Hardware is the physical, tangible parts of a computer.[7]
Input Input is where you would enter data to the com- puter, usually be means of peripherals. Such as key- board and mouse.[8]
Internet Simply put the internet is a network of net- works, connecting millions of computers together.[9]
Internet service provider The internet being a network of networks, you must be able to connect to said net- work and the only way is through an internet service provider(ISP). Generally the ISP is a large company that you would pay monthly for this service.[10]
Operating system An operating system (OS) is the ma- jor system software that controls all other system ap- plications, and manages the computer hardware. All PC’s need an OS.[11]
Output Output occurs after the computer processes the data you inputted and displays said data.[12]
1.15.2 Review Questions
1. Keyboards and mice are two forms of _______ de- vices? 2. Microsoft word and windows media player are exam- ples of ________ 3. Comcast and AT&T are _________ 4. The initial start up for a computer is the ____ se- quence. 5. Before it is information it is ____. 6. The ___ helps to identify websites by a specific name. 7. The chip inside the computer which is essentially the “brain” of the whole system is called the ______ 8. The physical parts of a computer are _______ 9. A network of networks is called the ______ 10. When sending a digital message from one computer to another you are using your _______
1.15.3 References [1] Wikipedia: Application software
[2] Wikipedia: Boot up
[3] Wikipedia: Computer
[4] Wikipedia: Domain name
[5] Wikipedia: Electronic mail
[6] Wikipedia: Embedded system
[7] Wikipedia: Computer hardware
[8] Wikipedia: Input device
[9] Wikipedia: Internet
[10] Wikipedia: Internet service provider
[11] Wikipedia: Operating system
[12] Wikipedia: Input/output
1.15.4 Answers
1. Input devices 2. Application software 3. ISP(Internet service providers 4. Boot 5. Data 6. Web address or domain name 7. CPU 8. Hardware 9. Internet 10. E-mail
Chapter 2
Hardware
2.1 The System Unit
2.2 Data and Program Representa- tion
2.2.1 Digital data and numerical data
Most computers are digital computers which use a spe- cific language to communicate within itself in order to process information. If there are programs running in the background or a person is typing up a word docu- ment for example, the computer needs to be able to in- terpret the data that is being put into it by the human as well as communicate to working components within it- self. This language that digital computers use is called binary code and is a very basic form of language com- posed of only two figures; 1 and 0. Whereas the English language is composed of 26 figures which we commonly call the alphabet, computers use a language composed of only two figures, hence its name Binary Code. Binary lit- erally means two and refers to anything that consists of, involves, or indicates two. The language known as Binary Code operates on a system of 1’s and 0’s strung together. Each 1 or 0 is referred to as a “bit.” “Bits” are the smallest unit of data that a binary computer can recognize and ev- ery action, memory, storage, or computation that is done through a computer is composed of them. From playing music through your speakers to cropping a photograph, to typing up a document and preparing an important presen- tation all the way down the line to browsing the internet or picking up on a wifi signal in your area, everything uses “bits” to complete the task needed. “Bits” string into larger lines of information the way letters string into words and then sentences. When eight “bits” are com- pounded in this way they are then referred to as a “byte”. “Bytes”, which are made up of “bits”, are commonly used when referring to the size of the information being pro- vided. For example, a song that is downloaded may con- tain several kilobytes or perhaps even a few megabytes if it is a whole c.d. and not just a single track. Likewise, pic- tures and all other documents in general are stored on the computer based on their size or amount of bytes they con- tain. The amount of information that can be stored onto
a computer is also shown or displayed in bytes as is the amount left on a computer after certain programs or doc- uments have been stored. Since bytes can be extremely long, we have come up with prefixes that signify how large they are. These prefixes increase by three units of ten so that a Kilobyte represents 1,000 bytes, a Megabyte represents 1,000,000 bytes or one million bytes, a Giga- byte represents 1,0000,000,000 or one billion bytes, etc. Computers components have become so small that we can now store larger and larger amounts of data bytes in the same size computers resulting in the use of other larger prefixes such as Tera, Peta, Exa, Zetta, and Yotta. Be- low is a chart outlining the name of the prefix used and powers of ten they symbolize.
0 1 1 0 1 0 0 0
1 1 0 1 0 0 0 0 0
1 0 0 1 1 1 0 1
0 1 0 0 1 1 1 00
1 0 0 1 1 1 0 0
1 1 0 0 1 1 1 0
b)
a)
c)
Bit shift
Digital Data Representation, otherwise known as how the computer interprets data, is a key concept to understand- ing computer data processing, as well as overall func- tioning. Data is represented by particular coding sys- tems. The computer recognizes coding systems- rather than letters or phrases that the user of a computer views. The actual process of the computer understanding cod- ing systems is called digital data representation. A digital
23
24 CHAPTER 2. HARDWARE
computer operates by understanding two different states, on or off. This means that the data is represented by numbers- 0’s and 1’s, and is known as a binary computer. The binary code is a very basic coding system for com- puters to comprehend. An advantage to digital data com- puting lies behind the binary coding systems. Although the binary code has become decreasingly popular in the professional, recreational fields due to an increase in tech- nology, they still provide a use in programming. Digital data creates a simple way to duplicate and transfer infor- mation accurately from computer to computer, which is why it is still used today.[1] The terminology for the small- est unit of data is a bit, which consists of a single numeric value,0 or 1. Bytes, on the other hand, consist of group- ings of multiple groupings of bits. Bytes allow the com- puter hardware to work more quickly and efficiently.[2]
(from the SI page on Wikipedia): Representing data in a way that can be understood by a digital computer is called Digital Representation and Bi- nary Code is the most commonly used form of this. Bi- nary Code is a Numerical Representation of data that uses only 1 and 0 to represent every possible number. Mathe- matics uses 10 symbols ranging from 1 TO 0 and include 2, 3, 4, 5, 6, 7, 8, and 9 as well. This Numerical Repre- sentation of data is called the decimal numbering system because it uses ten symbols. As shown on the chart, the prefix deci symbolizes ten. In both systems, the position of each digit determines to which power that number is raised. In the deci-mal system each digit is raised by ten so that the first column equals 1 (10^1) or ten raised to the zero power, the second column equals 10 (10^2) or ten raised to the first power, the third column equals 100 (10^3) or ten raised to the third power and so on. How- ever, since Binary Code only operates with two symbols, each digit is a power of two instead of ten. In binary the first column equals 1 (2^0) or two raised to the zero power, the second column equals 2 (2^1) or two raised to the first power, the third column equals 4 (2^2) or two raised to the second power, the fourth column equals 8 (2^3) or two raised to the third power, and so forth. Be- cause the Binary system takes advantage of so few sym- bols, the result is that more positions for digits are used to express the same number than in decimal form, leaving long lines of information for even the simplest expres- sions.
2.2.2 Coding systems
There are a few different coding systems, EBCDIC, ASCII and Unicode. EBCDIC (extended binary coded decimal interchange code) was created for use in main- frames, developed by IBM. The code uses a unique com- bination of 0’s and 1’s, 8-bits in length, which allows for 256 different combinations. ASCII ( American standard code for information interchange) was created for a more personal use. ASCII uses a 7 bit code, though there is an extended code which adds an extra bit, which nearly dou-
ASCII Code Chart-Quick ref card
A motherboard with an AMD chip.
bles the amount of unique characters the code can repre- sent. however Unicode is a much longer string of code, between 8 and 32 bits. With over one million different possibilities, every language can be represented with this code, every mathematical symbol can be represented, ev- ery punctuation mark, and every symbol or sign from any culture.
100 101 102 103 104 105 106 107 108 109 10A 10B 10C 10D 10E 10F
110 111 112 113 114 115 116 117 118 119 11A 11B 11C 11D 11E 11F
120 121 122 123 124 125 126 127 128 129 12A 12B 12C 12D 12E 12F
130 131 132 133 134 135 136 137 138 139 13A 13B 13C 13D 13E 13F
140 141 142 143 144 145 146 147 148 149 14A 14B 14C 14D 14E 14F
150 151 152 153 154 155 156 157 158 159 15A 15B 15C 15D 15E 15F
160 161 162 163 164 165 166 167 168 169 16A 16B 16C 16D 16E 16F
170 171 172 173 174 175 176 177 178 179 17A 17B 17C 17D 17E 17F
180 181 182 183 184 185 186 187 188 189 18A 18B 18C 18D 18E 18F
190 191 192 193 194 195 196 197 198 199 19A 19B 19C 19D 19E 19F
1A0 1A1 1A2 1A3 1A4 1A5 1A6 1A7 1A8 1A9 1AA 1AB 1AC 1AD 1AE 1AF
1B0 1B1 1B2 1B3 1B4 1B5 1B6 1B7 1B8 1B9 1BA 1BB 1BC 1BD 1BE 1BF
1C0 1C1 1C2 1C3 1C4 1C5 1C6 1C7 1C8 1C9 1CA 1CB 1CC 1CD 1CE 1CF
1D0 1D1 1D2 1D3 1D4 1D5 1D6 1D7 1D8 1D9 1DA 1DB 1DC 1DD 1DE 1DF
1E0 1E1 1E2 1E3 1E4 1E5 1E6 1E7 1E8 1E9 1EA 1EB 1EC 1ED 1EE 1EF
1F0 1F1 1F2 1F3 1F4 1F5 1F6 1F7 1F8 1F9 1FA 1FB 1FC 1FD 1FE 1FF
Non-Latin European scripts
African scripts
Middle Eastern and Southwest Asian scripts
South and Central Asian scripts
Southeast Asian scripts
East Asian scripts
American scripts
Cuneiform
Hieroglyphs
Notational systems
Symbols
Unallocated code points
As of Unicode 9.0
Roadmap to the Unicode SMP
Unicode is universal. With using 0’s and 1’s to represent different data, it has become fit for any language used all over the world. This code is replacing ASCII (American
2.3. THE SYSTEM UNIT - THE MOTHERBOARD AND CPU 25
Standard Code for Information Interchange) because the characters in this code can be transformed into Unicode, a much more practical system for data. ASCII is known as the alphabet code, and its numbering codes range from 0 all the way to 127 considered to be a 7 bit code. Alpha- bets vary from language to langue, but 0’s and 1’s can be understood worldwide. These codes apply to binary coding systems, meaning the computer understands two states of either On or Off. The problem with Unicode is that it is not compatible with each computer system used today. Windows 95/98 does not have the ability to run Unicode while other Windows such as NT and 2000 are closer to being able to. There is a program Sun Microsys- tem’s Java Software Development Kit which allows you to convert files in ASCII format into Unicode. While Uni- code is a huge improvement for coding systems today, it cannot process all symbols that are possible, leaving room for new systems to one day take its place.[3]
2.2.3 Graphics Data
Image where individual pixels can be seen.
One type of multimedia data is graphics data. These data are of still images, and can be stored in the form of a bitmap image file. A bitmap image is a type of graphic that contains pixels, or picture elements, that are arranged in a grid-like pattern.[4] Each pixel is made up of a specific group of numbers which corresponds to the color, and the color’s intensity. Although there are a few other key factors when determining the detail quality of an image, pixels play an important role. An image with many pixels allows there to be more potential of higher quality in that image. However, this doesn’t mean that more pixels in an image definitely results in a higher quality picture.[5] When shopping for digital cameras consumers must be aware of the amount of megapixels, or pixels by the mil- lion, the cameras in front of them have. Today, an aver- age person wishing to take decent and basic everyday pic-
tures will be satisfied with about an 8 megapixel camera. In fact, many new smartphone cameras use 8 megapixels, like the Apple iPhone 5C, a popular smartphone released in September 2013. Someone with different intentions of using images, perhaps for making high definition prints, will require a camera with more megapixels. This would allow for their prints to be large, but with appropriate and exceptional quality.[6]
2.2.4 Audio Data
Audio Data is very similar to graphics data in that it is understood in pieces. Instead of using pixels, however, audio data uses samples. Audio data is usually recorded with an input device such as a microphone or a MIDI con- troller. Samples are then taken from the recording thou- sands of times every second and when they are played back in the same order, they create the original audio file. Because there are so many samples within each sound file, files are often compressed into formats such as MP3 or MP4 so that they take up less storage space. This makes them easier to download, send over the internet, or even store on your MP3 player.
2.2.5 Video Data
Video data is also similar to graphic and audio data, but instead of using pixels or samples, video data is recorded with the use of frames. Frames are still images that are taken numerous times per second and that when played simultaneously, create a video (most films are recorded using twenty-four frames per second).[7] Similar to audio data, because video data contains so much information, the files can be compressed, making it possible for full length movies containing thousands of frames to be stored on optical discs.
2.3 The System Unit - The Mother- board and CPU
Motherboard
“The motherboard can be thought of as the “back bone” of the computer.” This quote is from the article Motherboard. Inside the system unit contains the moth- erboard. The motherboard is the “glue” of the computer. It connects the CPU, memory, hard drive, optical drives, video card, and sound card together. The front of the motherboard are peripheral card slots. The slots contain different types of cards which are connected to the moth- erboard. The left side of the motherboard contain ports. The ports connect to the monitor, printer, keyboard, mouse, speakers, phone line, and network cables.[8]
Like many of the components of computers, mother-
26 CHAPTER 2. HARDWARE
Realtimeclock Motherboard Baby AT crop
boards have not always been as advanced as they are to- day. Motherboards on early PCs did not have many inte- grated parts located directly on the board. Instead, most of the devices, such as display adapters and hard disk controllers, were connected through expansion slots. As technology advanced, more and more devices were built in directly to the board itself. At first, this began to cre- ate problems as manufacturers began to find that if one of the devices on the motherboard was faulty or in some way damaged, that the entire motherboard must be replaced. This led manufactures to change the design in a way that allowed them to remove faulty parts easily and replace them, especially parts that are growing and changing so quickly, such as the RAM or CPU. Today, a motherboard comes equipped with many parts working in conjunction with each other. One can find anything, from back up bat- teries, keyboard and mouse connectors, to cache memory chips, in close proximity to the CPU. The computer is able to do tasks faster as its components continue to be closer to one another. The advancement of technology has allowed for these parts to become smaller and more powerful, allowing more surface area on the motherboard to fit more devices. It is common today to find even audio and video components built into it as well. With technol- ogy moving as fast as it is, one may wonder what a moth- erboard will be capable of containing in the near future.[9]
• Annotated Motherboard
• Motherboard Diagram
CPU
The CPU is the abbreviation for the central processing unit. The computer needs the CPU in order to function correctly. It is known as the brains of the computer where the calculations occur. The microprocessor and the pro- cessor are two other names for the central processing unit. The Central processing unit attaches to a CPU socket on the motherboard. A common CPU is called the multi- core CPU. This specific type of CPU is efficient because
Motherboard
it allows computers to work on more than one task at a time. Also, these multi core CPU’s experience less over heating than the original CPU which causes much less problems to the computer. A typical CPU is two by two inches.
• Intel i7 940
• AMD Dual Core
History of the CPU
The Intel 4004
2.4. THE SYSTEM UNIT - MEMORY, BUSES, PORTS 27
The first CPU ever made was the Intel 4004, which was designed by Federico Faggin. After ten months of Faggin and his colleagues working on the chip, it was released by Intel Corporation in January 1971. Even though this first generation, 4-bit microprocessor could only add and subtract, it was a major breakthrough in technology. The amazing quality was that all of the processing was done on one chip, as opposed to prior computers which had a collection of chips wired together. This invention lead to the first portable electronic calculator.[10]
While technology has advanced quite a bit since 1971, old technology is not as “out-of-date” as one thinks. There are still CPU chips made in the 1970’s and 1980’s that are still being used today. Personal computers, such as PC’s and Mac’s, use faster, more up-to-date CPU’s because the users run many programs at the same time. However, the more simple computers embedded in cars, printers, and microwaves can still use the older forms of microproces- sors. For example, one famous CPU was the MOS 6502, made in 1975, and it was still being used in many ap- pliances up until 2009. Control processing units are the key component in any computer, and thus sometimes the simpler styles work best.[11]
2.4 The System Unit - Memory, Buses, Ports
2.4.1 Memory
The Template:Gaps byte (512×220) capacity of these RAM mod- ules is stated as “512 MB” on the label.
Memory identifies data storage that comes in the form of chips and is used to store data and programs on a tem- porary or permanent basis. There are two main types of memory storage which are random- access memory (RAM) and read-only memory (ROM). Inside the sys- tem unit, ROM is attached to the motherboard. Random- access memory can read data from RAM and write data into RAM in the same amount of time. RAM is measured in bytes and includes the cache memory and registers. It
is volatile which means that it loses the information/data stored on it when the power is turned off. In order to re- trieve an important file at a later date, one needs to store it on a separate, non-volatile, storage medium (such as a flash drive or hard-drive) so that, even though the infor- mation is erased from RAM, it is stored elsewhere. RAM has different slots where it stores data and keeps track of addresses. Read-only memory cannot be written to and is non-volatile which means it keeps its contents regardless of whether the power is turned off or not. Flash memory (solid-state) is starting to replace ROM. It is also a non- volatile memory chip that is used for storage on devices, like mobile phones, tablets, digital cameras, etc. This type of memory can often be found in the form of flash drives, SD cards, and Solid-State hard drives. The reason for this is so that the data can be quickly updated over time while taking up a smaller amount of physical space in comparison to its precursors. Flash memory is also more resistant to outside forces, such as electro-magnetic fields or shock, than other memory alternatives such as traditional hard-drives.
A microprocessor, which may use cache memory.
Cache memory is a specific kind of memory that al- lows a computer to perform certain tasks much more quickly. A good analogy from HowStuffWorks compares the computer to a librarian, data to books, and cache to a backpack.[12] Suppose somebody walks into a library and asks the librarian for a copy of the book Moby Dick. The librarian goes back into the room full of books, grabs that book, and gives it to the reader. Later that day, the reader returns, having finished the book, and gives it back to the librarian, who returns it to the same storage room. Then, a second reader walks in asking for the same book, Moby Dick. The librarian has to get up and go all the way back to the room in order to get the book he was just handling, which is a waste of time. Instead, suppose the librarian had a backpack that could store up to 10 books. When the first person returns Moby Dick, the librarian puts it into his backpack instead (after making sure the back-
28 CHAPTER 2. HARDWARE
pack doesn't have 10 books in it already.) Then, when the second person comes in requesting that same book, the librarian can just check his bag, get the book out, and hand it to the second person without having to walk all the way back into the other room. Cache memory functions like that backpack. It stores previously accessed data in a specific area with a limited amount of memory so that the processor can get this data much more quickly.
2.4.2 Ports
Parallel Printer Port
Ports are on the outside of the system unit and they are used to connect hardware devices. There are physical ports and virtual ports. A physical port is a physical con- nection to a computer where data is transferred. It is when something is physically plugged into the computer or some other device. Virtual ports allow software ap- plications to share hardware resources without having to physical connect to each other or to interfere with one another.[13] Parallel ports are most often used with a key- board, printer or mouse, but these are more commonly known as legacy ports instead. Each port has a certain connector to plug it into the computer. Different type of ports would be power connectors, VGA monitor port, USB ports, Firewire port, HDMI port, Network port, au- dio ports, and empty slots. The connectors would be Monitor (VGA, HDMI), USB, Firewire, network, and au- dio connector. Each port has also a different purpose and connector. Almost all PCs come with a serial RS-232C port or a RS-4222 port and they are used for connect- ing a modem, mouse, or keyboard. They also have par- allel ports that are used to connect printers. These are also considered USB ports because they are physical ports and which standardize communications between comput- ers and peripheral. USB ports were created in the mid 1990’s; USB stands for Universal Serial Bus. There are also network ports used to connect a computer to a net- work. Ethernet was developed in the 1980s and it is a system for connecting a number of computer systems to form a local area network.
A serial port is used to connect modems to personal com- puters. The term “serial” signifies that data sent in one direction always travels over a single wire within the ca- ble. The last main kind of port is the FireWire, which are used to connect FireWire devices to the computer via a FireWire connector. These are used with mostly digital video cameras and other multimedia devices.
2.4.3 Thunderbolt port
Thunderbolt-Connector
A Thunderbolt port connect peripheral devices through that cable. These ports allow for you to connect more de- vices to your computer and is very fast. Thunderbolt ports use hardware controllers I/0 protocols onto one efficient protocol with the use of just one cable. I/O technology is input and output is a device that that transfers the data to the computer peripherally (a CD-ROM would be an example of an I/O technology).This port lets there to be full bandwidth for both directions of the port, thus allow- ing the user to faster and more efficient with the ports it has to connect. This type of technology allows for people to plug in as many devices they could use on their com- puter and not slowing any of those devices down. The thunderbolt port is also small so it is easy to travel with as well.[14]
2.4.4 Power supply unit
Computers need power. There are two main functions the PCUs are responsible of. The first is to convert the type of electrical power available at the wall outlet such as110V 60Hz AC (alternating current) or 230v 50Hz AC to the type the computer circuits can use. The other cru- cial task is to deliver low voltages to each device due their requirements. The converting currents could be represented either by built in PSU (desktops, servers, mainframes) or by the separate power supply adapters for computers with rechargeable batteries inside (laptops, tablets). Three main voltages are used to power com- puter : +3.3v, +5v, and +12v DC, Usually, the +3.3 or
2.5. HOW THE CPU WORKS 29
PSU-gold-rear
+5 voltages are being used by logic circuits and some dig- ital electronic components (motherboard, adapter cards, and disk drive logic boards) while the motors (disk drive motors and any fans) use the +12v power. The power sup- ply must provide a good, steady supply of DC power for the proper system operation. Devices that run on voltages other than these must be powered by onboard voltage reg- ulators. For example the CPUs operate 1.5V and 2V and require very stable power with high power consumption. [15]
2.4.5 Ethernet Cable in Theatre
A commonly used cable today is Ethernet cable. You a probably most familiar with its use involving the internet in your home, mostly going from your modem, to another computer of to a Wi-Fi router. However, the use of Eth- ernet cable has been instrumental in the changing would of technical theatre. Before its introduction, the most common computer cables used in theatre were DMX and XLR, for lighting and sound respectively. This issue with this is that each cable can only carry the information for one device, be that a microphone or light. In addition, if these cables are stored improperly, they can corrupt the information being transmitted. Ethernet is much smaller, and can transmit far more data. Also, there is less of a danger regarding storing cable. Ethernet, combined with new operating system and equipment, has made thing far more efficient. For example, an analog board must have one XLR cable go to each microphone, so if you wanted to run 40 microphones, you must have 40 channels avail- able on your soundboard. Also, the size of a cable with 40 smaller lines inside it can reach a one-inch diameter, and can weigh several hundred pounds. Now, a digital soundboard can control up to 100 microphones on a sin- gle Ethernet cable.
An Ethernet cable
This is a Yamaha digital soundboard capable of running ethernet
2.5 How the CPU Works
CPU Architecture and Components
As previously discussed on this page, the CPU is a com- plex piece of the computer made up of many parts. The way these parts all fit together inside the CPU is differ- ent in each processor but they mainly contain the same parts from device to device. The most abundant part in the CPU would be the transistor. Modern CPU’s typi- cally hold several hundred million transistors with some of the more high-end computers holding over a billion, and for good reason. Calculations in a computer can be performed thanks to the combination of transistors turn- ing off or on. Besides these transistors, there are sev-
30 CHAPTER 2. HARDWARE
A CPU core
eral parts that make up the CPU. Some of these include the arithmetic/logic unit (ALU) and floating point unit (FPU), the control unit, and the prefetch unit. The ALU is the part of the CPU that deals with the mathematics in- volving whole numbers and any functions done with those numbers. The FPU takes care of the mathematics with other numbers like fractions, or numbers with decimal places.[16] These two parts work hand in hand, using arith- metic and logical processes, to allow you to perform ba- sically any function you perform on your computer. The control unit takes charge in controlling where and when information is transferred to and from the CPU. When in- formation leaves the control unit, it is usually sent to the ALU/FPU where it can be converted into a process. The prefetch unit, as its name implies, fetches data before it is needed. It uses a sequence of processes to guess what information will be needed next, and have it readily avail- able before the time it needed. Other components of the CPU include the cache, the decode unit, and the bus in- terface unit. The cache serves as high-speed memory for instructions that the CPU would like to access faster, in other words instructions that the CPU would rather avoid
retrieving from RAM or the hard drive. The decode unit, just as it sounds, decodes instructions. Once the prefetch unit fetches data, the data goes through the decode unit so the instructions can be understood by the control unit. The bus interface unit allows communication between the the core and other CPU components. Think of it as liter- ally a bus, taking information from one place and trans- porting it somewhere else. [17]
2.6 How the CPU Works
The Internal Clock
Every computer actually has two different clocks. One is the virtual or system clock that runs and is displayed whenever the computer is on and running.[18] The other is a real-time clock or hardware clock that runs continu- ously, and is responsible for tracking the correct time and day. This device does not count time in days and hours for example. Instead it just runs a counter at times per second. As far as the century goes, it is the job of the BIOS, the Basic Input-Output System, to track this and save it in the non-volatile memory of the hardware clock. These two clocks run independently on each other. The system clock is physically a small quartz crystal that can be found on the motherboard. It also helps synchronize all computer functions by sending out signals- or cycles- on a regular basis to all parts, much like a person’s heart- beat. Hertz is the unit of measure used to count the num- ber of cycles per second. For example, one megahertz is one million ticks of the system clock. This clock is very important to the CPU because the higher the CPU clock speed, the more instructions per second it could process. Since the entire system is tied to the speed of the system clock, increasing the system clock speed is usually more important than increasing the processor speed. PCs in the past only had one unified system clock with a single clock, which drove the processor, memory, and input/output bus. However, as technology advanced, the need for a higher speed, and thus multiple clocks, arose. Therefore, a typical modern PC now has multiple clocks, all running at different speeds to enable any data to “travel” around the PC. Furthermore, two CPUs with the same clock speed will not necessarily perform equally. For instance, if an old microprocessor required 20 cycles to perform a simple arithmetic equation, a newer micro- processor can perform the same calculation in a single clock tick. Therefore, even if both processors had the same clock speed, the newer processor would be a lot faster than the old. As mentioned previously, a CPU serves as a great ex- ample for the synchronization that the system clock per- forms. To synchronize, most CPUs start an operation on either the falling edge, when the clock goes from one to zero, or the rising edge, when the clock goes from zero to one. All devices, such as a CPU, synchronized with
2.6. HOW THE CPU WORKS 31
The system clock alternates between zero and one at a periodic rate.
the system clocks run at either the system clock speed or at a fraction of the system clock speed; therefore, the CPU is unable to perform tasks any faster than the clock. For example, during each system clock tick, a CPU clock speed of 2 GHz allows the CPU clock to “tick” 10 times, executing one or more pieces of microcode. This abil- ity to process multiple pieces of microcode at one time is known as superscalar. [19]
The Machine Cycle
Instr. No.
1
2
3
4
5
IF ID MEM WB
Pipeline Stage
Clock Cycle
1 2 3 4 5 6 7
EX
IF ID MEM WBEX
IF ID MEM WBEX
IF ID MEMEX
IF ID EX
5 Stage Pipeline
A machine cycle is a term often used when discussing the clock. It has four main parts- fetch, decode, execute, and store. The machine cycle occurs whenever a CPU processes a single piece of microcode. The fetch opera- tion requires the program instruction to be fetched from either the cache or RAM, respectively. Next, the instruc- tions are decoded so that the ALU or FPU can understand it, known as the decode operation. Then, the execute op- eration occurs when the instructions are carried out. Fi- nally, the data or result from the ALU or FPU operations is stored in the CPU’s registers for later retrieval, known as the store operation. A fifth possible step in the cycle is the register write back operation, which occurs in cer- tain CPUs. The RISC CPU, which stands for reduced instruction set computer processing unit, is an example that uses the fifth step of the machine cycle. Machine cy- cles can only process a single piece of microcode, which forces simple instructions, like addition or multiplication, to require more than one machine cycle. In order to make computers faster, a system known as pipelining has been created. Originally, one machine cycle would have to fin- ish processing a single instruction before another instruc- tion could be carried out through a second machine cycle. With pipelining, as soon as an instruction passes through
one operation of the machine cycle, a second instruction can start that operation. For example, after one instruc- tion is fetched and moves on to decoding, the CPU can fetch a second instruction. This invention allows for mul- tiple machine cycles to be carried out at the same time, which boosts the performance of the computer. Also, be- cause of how fast the CPU can work with pipelining, it can be measured in millions of instructions per second.[20]
Typical CPU Components (continued)
Just like a real life bus transports people, the bus interface unit carries information from one destination to another
ANS700-CPU-board
To round up the simplified inventory of a CPU’s guts, we have the decode unit, the registers and internal cache memory, and the bus interface unit. Of the remaining three sections of a CPU, the decode unit is easiest to understand because its job immediately follows the job of the prefetch unit. After the prefetch unit collects the data, the decode unit decodes the data into a language that is easier for the ALU/FPU to understand. It does that by consulting a ROM memory that exists inside the CPU, called microcode.[21] The registers are used during processing; they're groups of high-speed memory located within the CPU that can be accessed by the ALU and FPU, or for other assorted optimization purposes. While the registers provide the fastest speed of memory, their space is extremely limited. In the cases where the small register space isn't good enough, there are the caches to save the day. The cache is used by the CPU for mem- ory which is being accessed repeatedly, speeding up the access time and having a slightly larger storage than the
32 CHAPTER 2. HARDWARE
register.[22] The bus interface unit does exactly what it sounds like; it buses the data back and forth, connecting the core of the CPU to interact with other components.[23]
Another aspect of the CPU is improving processing per- formance. In the past most CPUs designed for desktop computers had only one single core, so the only way to improve performance was to increase the speed of the CPU; however, increasing the speed also caused the CPU to heat up. So now a days CPU have multiple cores in or- der to increase the performance. In an article by Sebas- tian Anthony on Extreme Tech on September 10, 2014 he explains how the new Apple iPhone 6 CPU will be able to perform faster. The new Apple iPhone is going to have a new A8 SoC. It is going to have more transistors, which if you recall, are small devices made of semiconductor ma- terial that acts like a switch to open and close electrical circuits. This new A8 chip will have about 2 million tran- sistors according to the article Mr. Anthony wrote. Mr. Anthony states, “The A8 SoC will, according to Apple, be about 25% faster than its predecessor in CPU tasks.” As of now, this information is coming from graphs and information that Apple has shared. The thing to know and realize is that companies are constantly striving to improve performance and reworking the architecture of the CPU can improve the performance.[24]
2.7 Improving the Performance of Your Computer
Spindle Head
Actuator Arm
Actuator Axis
Actuator
IDE Connector
Jumper Block
Power Connector
Platter
Computer Hard Drive
2.7.1 Add More Memory and Buy a Larger or Second Hard Drive
When it comes to technology, there is no question that newer is better. New systems are able to process faster, store more, and run more applications at once. However, it is obviously not within everybody’s means to just run out and purchase the newest and greatest technology the minute it hits the market. Technology is expensive, and
therefore it is important to know your options. For exam- ple, if you have a computer that is a couple of years old, it is not unreasonable to assume that the hard drive and memory on the system are starting to slow down. How- ever, what many people may not know is that buying a new computer is not the only solution to the problem. You can add memory to your old system simply by purchas- ing a new memory card and installing it into the computer hardware. By doing this, you are saving money and buy- ing yourself a little bit more time with the computer.[25] Another way to speed up your computer with out having to invest in a whole new one is by buying a second hard drive. When the original hard drive starts to fill up, one can simply purchase either an internal or external hard drive for the computer and drastically increase the oper- ating speed.[26]
2.7.2 Upgrade To A Solid-State Drive
An Intel X25-M Solid-State Drive
Since solid-state drives (SSDs) are hard drives that use flash memory technology instead of hard disk platters they have no moving parts. They also no longer make noise, consume less power thus generating less heat, and are much faster than hard drives. Since they are much faster than hard drives, the performance of the computer would also be improved. Running programs, opening files, saving things to the disk, even browsing the web will be much faster. Also with a mechanical hard drive, phys- ical heads have to move around to read data from the disk while in a solid-state drive data can be read and written on any location thus there is no penalty in performance. Not only are solid-state drives faster but they have also be- come less expensive that upgrading to them is much more affordable and reasonable. Even further, installing solid- state drives is not too difficult or complex. It is basically the same as installing regular hard drives. Also if the de- cision of upgrading to solid-state drives seems a little too final, it is possible to just add a solid-state drive alongside the hard drive. Thus not only having more space, but also having the ability to keep the old mechanical drive.[27]
2.7. IMPROVING THE PERFORMANCE OF YOUR COMPUTER 33
Internet Connection
2.7.3 Upgrade Your Internet Connection
If your system seems to be running poorly while using the internet, you may have to upgrade your internet connec- tion. Upgrading your internet connection may become more costly but there is a significant change in the pro- cessor. Your first step would be to discuss any upgrades or check if the provider needs to be enhanced in any way. Then find a browser that is suitable for your connection type. With that being stated, you can change the settings on the router in order to speed up the internet connec- tion. In order to prevent your internet connection becom- ing slower, it’s highly suggested to have a password in or- der to access the internet. In addition, every computer owner should provide maintenance to their computer in order to prevent viruses or any bugs the computer may receive but it also prevents an internet connection from being slow. In order to do so, keep up with upgrading and cleaning the computer because the more the computer is trying to maintain, the slower the internet connection may become.[28]
2.7.4 System Maintenance
In order for computers to operate at their maximum effi- ciency, users must be aware of the importance of system maintenance because, over a period of time, one may no- tice a reduction in system performance. This can be at- tributed to a number of common factors that lead to the degradation in performance. One major reason is hard drive fragmentation. As more programs are installed onto the hard drive, the pieces of the files that are on those programs take longer to be located. The longer pieces of the program become shorter and fragmented, leading to a longer waiting period for the user as the computer searches for these scattered pieces. Related to this, al- though not nearly as detrimental to system performance as fragmentation, is the cluttering of pieces and refer-
Video Graphics Card
ences to uninstalled programs in the operating system. For Windows users, this occurs in the Registry. After the user uninstalls a program, there are references to that program left behind in the Registry that can possibly im- pact performance. However, performance is not neces- sarily the issue here. For example if the user is going to update the system by switching from an Nvidia graph- ics card to an AMD one, it might be a good idea to not only uninstall all drivers and related programs but also to clean the Registry of any references to the Nvidia drivers and software (in order to avoid possible conflicts when the AMD card is installed). This will ensure a “clean” install of both the hardware and software components. A free registry cleaner utility one can use is CCleaner.[29]
Temporary files (e.g. from web browsers and installation programs) can take up valuable storage space if they are not removed after extended periods of times. Also, users should be aware of the programs they are installing and decide which specific programs are to run at startup. Too many programs can slow down the initial startup time of the computer because it must launch program after pro- gram. Only those programs that are necessary should be included, and to check for this, click Start (in the lower- left Windows icon) and enter the command msconfig in the search tab. This will open the System Configuration window. Programs that run at startup are listed under the Startup tab. Here the user can enable or disable programs, which can affect startup time. Another important factor in determining system perfor- mance is the corruption of system files by malware. Viruses, worms, trojans, spyware, and other forms of malware can infect a system by various means, so it is im- portant for the user to be aware and defensive. Anti-virus programs and other security software provide protection from malware, so it is recommended that a user has some sort of program installed and regularly scans the system
34 CHAPTER 2. HARDWARE
for any traces. Lastly, dust can accumulate in and on heatsink fans (e.g. processor and graphics card), case fans, ports, power sup- plies, and motherboards. Every internal component can accumulate dust, and this can be a major issue for sys- tem integrity because dust acts as an insulator by trapping heat. Fans with too much dust do not operate efficiently because the fins do not spin quickly, which further exac- erbates the heating problem. Not only that, but dust can also cause electrical shorting of the circuits, which can irreversibly damage components.[30] To clean the com- puter, power off the system, which includes turning off the power supply. It should not be connected to any source. Then open the case and use a can of compressed air to blow out the dust wherever it may be. The goal is to rid the case of any remnants of dust. Following this and the other tips listed above will help ensure reliable performance and a longer lifespan for the computer.
2.7.5 Future Trends
The supremacy of supercomputers may not be as evident in the future.
The challenge of making computers faster and more ef- ficient has brought new ideas to the table of technol- ogy. One such idea is nanotechnology, which uses mi- croscopic components only nanometers in length. Car- bon nanotubes are already being used in technology to- day in products such as lithium ion batteries because of their great performance conducting electricity. Other nanotechnology includes nanoparticles and nanosensors. Another idea that has received increased recent attention is quantum computing. These computer’s go beyond reg- ular computers’ binary system using qubits, which can be either a 1, a 0, or both simultaneously.[31] Although these computers are only able to perform seemingly sim- ple tasks like sudoku puzzles as of recently, their potential is outrageous for tasks such as encryption. Optical com- puting is another form of future technology which uses light waves to transfer data. Since the in fared beams do not interfere with each other, optical computers can be much smaller and more efficient that electronic comput- ers. In fact, once optical computers have been mastered
the computers will be able to process information at the speed of light using very little power at all.[32] In years to come, the extraordinary power of supercomputers is pre- dicted to be available in more common computers using technology like terascale computing to process at incred- ible speeds.
2.7.6 Review Definitions
Application Software: Programs that enable users to perform specific tasks on a computer, such as writing let- ters or playing games. Computer: A programmable, electronic device that ac- cepts data input, performs processing operations on that data, and outputs and stores the results. Data: Raw, unorganized facts. Information: Data that has been processed into a mean- ingful form. Computer Network: A collection of computers and other hardware devices that are connected together to share hardware, software, and data, as well as to com- municate electronically with one another. Hardware: The physical parts of a computer system, such as the keyboard, monitor, printer, and so forth. Internet Appliance: A specialized network computer designed primarily for Internet access and/or e-mail ex- change. Operating System: The main component of system software that enables a computer to operate, manage its activities and the resources under its control, run applica- tion programs, and interface with the user. Output: The process of presenting the results of pro- cessing; can also refer to the results themselves. Software: The instructions, also called computer pro- grams, that are used to tell a computer what it should do. Storage: The operation of saving data, programs, or out- put for future use. URL: An Internet address (usually beginning with http://) that uniquely identifies a Web page. Web browser: A program used to view Web pages. World Wide Web (WWW): The collection of Web pages available through the Internet. Web server: A computer that is continually connected to the Internet and hosts Web pages that are accessible through the Internet.[33]
2.7.7 Review Questions
1) What is the key element of the CPU? 2) What are the connectors located on the exterior of the
2.8. REFERENCES 35
system unit that are used to connect external hardware devices? 3) What is an electronic path over which data travels? 4) _________ are locations on the motherboard into which _________ can be inserted to connect those cards to the motherboard. 5) What is used to store the essential parts of the operating system while the computer is running? 6) The ______________________ consists of a variety of circuitry and components that are packaged together and connected directly to the motherboard 7) A _________ is a thin board containing computer chips and other electronic components. 8) The main circuit board inside the system unit is called the ___________ . 9) Before a computer can execute any program instruc- tion, such as requesting input from the user, moving a file from one storage device to another, or opening a new win- dow on the screen, it must convert the instruction into a binary code known as ____________. 10) In order to synchronize all of a computer’s operations, a __________ is used.[34]
2.7.8 Review Answers
1) Transistor 2) Ports 3) Bus 4) Expansion slots, Expan- sion cards 5) RAM 6) Central Processing Unit 7) Circuit Board 8) Motherboard 9) Machine Language 10) System Clock
2.8 References [1] http://courses.cs.washington.edu/courses/cse100/99au/
FIT100-99.L5.pdf
[2] http://compnetworking.about.com/cs/basicnetworking/ f/bitsandbytes.htm
[3] http://www.peachpit.com/articles/article.aspx?p= 31286&seqNum=16
[4] http://desktoppub.about.com/od/glossary/g/bitmap.htm
[5] http://www.cambridgeincolour.com/tutorials/ digital-camera-pixel.htm
[6] http://www.cambridgeincolour.com/tutorials/ digital-camera-pixel.htm
[7] https://en.wikipedia.org/wiki/Frame_rate
[8] http://pcsupport.about.com/od/componentprofiles/p/p_ mobo.htm
[9] http://www.pctechguide.com/motherboards/ evolution-of-the-motherboard
[10] http://www.howstuffworks.com/microprocessor.htm
[11] http://www.cpushack.com/life-cycle-of-cpu.html
[12] http://computer.howstuffworks.com/cache2.htm
[13] http://www.computerports.net/
[14] http://www.tomshardware.com/reviews/ thunderbolt-performance-z77a-gd80,3205.html
[15] http://www.instructables.com/id/ Power-Supply-For-Arduino-power-and-breadboard
[16] http://www.techterms.com/definition/alu
[17] http://education-portal.com/academy/lesson/ central-processing-unit-cpu-parts-definition-function. html#lesson
[18] http://scholar.lib.vt.edu/vtpubs/spectrum/sp970911/3b. html
[19] https://courses.engr.illinois.edu/ece390/books/artofasm/ CH03/CH03-2.html
[20] http://www.jegsworks.com/lessons/lesson4/lesson4-4. htm
[21] http://www.hardwaresecrets.com/printpage/ How-a-CPU-Works/209
[22] http://www.moreprocess.com/devices/ computer-memory-hierarchy-internal-register-cache-ram-hard-disk-magnetic-tape
[23] http://www.electronics.dit.ie/staff/tscarff/BIU/bus_ interface_unit.htm
[24] http://www.extremetech.com/computing/ 189787-apples-a8-soc-analyzed-the-iphone-6-chip-is-a-2-billion-transistor-20nm-monster
[25] http://www.pcworld.com/article/129177/article.html
[26] http://windows.microsoft.com/en-us/windows7/ install-or-remove-a-hard-disk-drive
[27] http://www.howtogeek.com/194750/ its-time-why-you-need-to-upgrade-to-an-ssd-right-now/
[28] http://www.auslogics.com/en/articles/speed-up-internet/
[29] http://www.piriform.com/ccleaner
[30] http://www.computerdust.com/downloads/special_ report_on_the_effect_of_dust_on_electronics.pdf
[31] http://www.dwavesys.com/quantum-computing
[32] http://www.extremetech.com/extreme/ 187746-by-2020-you-could-have-an-exascale-speed-of-light-optical-computer-on-your-desk
[33] http://coursemate.cengage.com/CPReader/View/ 9781133114598/default.aspx?eISBN=9781133114598# 70a7d313-0a5d-4ddc-ba5c-766e5fb0dc77
[34] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013922
36 CHAPTER 2. HARDWARE
2.9 Storage
2.10 Storage System Characteris- tics
2.11 Floppy Disk
The floppy disk is an archaic physical external storage de- vice that is now obsolete. There might be some banks that still use this storage medium, but any business or person who is considered computer literate does not use this sys- tem to store information. The down sides to floppy disks are that they are not compatible with any device that is contemporary, their security is non-existent, and the stor- age capacity is low - usually with a maximum of 1.44MB. The last version of a floppy disk was released in 1987 by IBM.
2.11.1 Storage Media, Storage Technol- ogy, and Volatility
Types of Storage Media
Storage media is the hardware in which information is physically stored. This differs from the storage device which is usually the docking bay for the storage medium. One example of a storage device would be your CD/DVD drive in which you place your disks when inserting them into your computer or your USB flash drive reader. Stor- age media would be the actual CD/DVD disk itself or the memory within your computer known as RAM. Storage media can be internal or external meaning that it can be either hard-wired to the computer, like the hard drive for example, or it can be a separate physical storage facility thats meant to be more mobile, like a USB flash drive, Ipod, or an external hard drive for instance. Internal stor- age media is usually faster since it is hard-wired to the desktop or laptop and does not requires any extra space outside of the computer. On the other hand, external me- dia is very mobile, can be transferred from one computer
to another rather quickly, and is easily secured in a safe place separate from your main working station. On top of this the Non-Volatility of these storage medias have made them very valuable. Normally when a computer is shut down, any unsaved information is wiped clean from the RAM, or if the information isn't being used, while the computer is still on, the RAM may delete it to make room for processes being recalled more frequently. Stor- age media on the other hand, saves data despite the com- puter being powered down and can only be deleted by the user. Because of this, storage media such as flash drives and data c.d.s are used for anything that would be needed for future reference.
Magnetic Hard Drive
Bouncing Wave or ASE from a Laser Disk
Storage Technology usually comes in three forms; mag- netic, optic, and solid state. Some common magnetic storage systems are hard drives, floppy disks, and cassette tapes. Though cassette tapes don't work with computers they use the same technology and this is why they are worth mentioning. In each case this type of technology stores binary code using polar alignments on the magnetic medium and can change those alignments as needed when information is altered, deleted, or rewritten. The magnet does this by converting the binary code from 1’s and 0’s to positive and negative charges, respectively, which are recorded on an iron oxide film inside the media. Optics use laser beams which rely on marking the media. In this case, lasers burn in lines of data which represent the bi- nary code it is converting. “Rewritable” media has also become a popular choice for those who want to reuse the same disk. Rewritable media relies on changing the re-
2.11. FLOPPY DISK 37
flectivity of the media instead of scarring it. When the binary number 1 is recognized, the laser alters the reflec- tion of the discs surface in certain spots. Data is then separated by the pits in between reflectivity which rep- resent the binary number 0 so that 1’s alter the reflec- tion and 0’s leave the reflection of the media as is. This creates a “bouncing-wave” like appearance on the surface of the disk called an Amplified Spontaneous Emission or ASE for short. Solid State Drives, or SSD’s as they are called, do not contain any moving parts such as lasers or magnetic heads. They operate electronically by stor- ing the binary code as electrons which are either trapped or not trapped inside the flash memory cells within the unit. These types of media tend to be faster than the other two since they rely on electrical polarity within a cell in- stead of electronic motors to be read or rewritten. This also makes them more resistant to shock, allows them to run more quietly, and reduces the latency of the media. Typical storage media of this kind are “jump” drives or “thumb” drives, but some computers use this technology in their hardware as well.
2.11.2 Clusters, Sectors, and Tracks
A
B C
D
Disk structure showing a track (A), a sector (B) and a sector of track (C) and a cluster of sectors(D).
Hard disks have many circular pieces called platters in- side them. These platters have two sides are made up of tracks, sectors, and clusters. A cluster is a group of sectors, and a sector divides tracks into pie shaped sec- tions. Each cluster, sector, and track is numbered in order to help the computer quickly locate where specific stored data is. For example, data can be saved to side 2, sector 1, track 5. A track can be compared to the grooves on a music record, because there are physical indents where the data is actually stored. Data is read and written by a read/write head, also commonly referred to as a “head.” Each platter has a head. When data is to be stored on
a hard disk, the heads will align with the same track on every platter, and write the data across each one. There are a few measurements you can take to see how well a hard disk preforms. The most important measurement is calculating seek time. Seek time will tell you how long it takes for a head to move from one track to another. The quicker the seek time the better because that would mean data can be reached faster.[1]
2.11.3 Random vs. Sequential
Sequential access
Random access 1 2 3 4 5 6 7 8
1 3 7 2 8 6 4 5
Random vs sequential access
When thinking of storage systems, one could presume that all of your data in one folder is located next to each other within the hard drive. This is false when talking about random access. With random access your informa- tion can be pulled from any location on the disk. Mean- ing, your one folder could have its data scattered about the physical hard drive. The benefit of this type of storage is that you could access data in any order. Think of it as your CD player, your favorite song ends and you want to hear it again just hit back and you instantly hear it again. It’s fast and nearly instantaneous, unlike sequential. You could think of sequential access like a cassette within a cassette player. When a song finishes and you want to listen to it again, you must rewind the cassette, or if you want to skip a song you must fast forward the tape.[2] This is used with magnetic tape drives which, are used for backup pur- poses. Even though in random access media devices may seem like data could be misplaced or somehow lost in the sea of data. When created, every file is given a unique name by the computer system, other wise called address- able media, in order to keep tabs on all the data. Random access and sequential access of data are two sep- arate ways a computer can access data. Random access is the ability to access data in any given location within the hard drive, quickly and efficiently. Most computers use random access today, because it saves the user time, as well as avoids confusion. Sequential access requires data being accessed in a sequence. Examples of sequen- tial access would be: data on a disk file, or magnetic tape data storage. This can be useful to some users, if they are purposely attempting to process a sequence of data elements in order. However, this can also be time con-
38 CHAPTER 2. HARDWARE
CDROM-Random Access
Tape-Sequential Access
suming for users who are trying to find a certain file on a disk or tape, which requires skimming through all of the data in a sequence. An example of a comparison be- tween random access and sequential access would be the A-Z method. Sequential access would inquire the user to go through letters A-Z to achieve the goal of meeting point” Z”; whereas with random access, the user is able to jump directly to point “Z”.
2.11.4 Storage Devices and Storage Media
The storage medium is a part of the storage system where the actual data is stored, such as on a DVD or a memory card. This medium can then be put into a storage device like a DVD player or phone to read this data. You usu- ally find these two parts to be separate pieces, making the storage medium removable. Some storage devices can be found inside of the system unit, while others are plugged into an external port. There are letters on the storage de- vice that go along with this that helps the unit to identify
USB Stick,Storage Medium
them. These letters or words describe where these are and what they are used for. For example, when you plug in a USB into the USB port on the computer, while viewing this USB in “My Computer” you will see a letter next to it verifying what it is used for in the system unit. Storage de- vices contain primary and secondary memory. Primary memory is volatile memory, which means that when the device is shut off, the information is lost. Secondary is the exact opposite, being non-volatile in that the memory remains even if the computer is turned off.[3] The prob- lem with these devices is you must be cautious with how they are treated, especially if they have important infor- mation. Misplacing or mistreating can result in a loss of important data that could be impossible to get back de- pending on the circumstances.
2.12 Hard Drives
Every computer contains one, if not two, hard drives. There are internal and external hard drives. The internal hard drive is located inside the system unit, and the ex- ternal hard drive is connected to the computer for extra storage. It is vital that an owner of a computer purchases an external hard drive to backup his or her computer in case it crashed. An external hard drive is extremely con- venient to store information; however, one must be cau- tious of the possibility of “hard drive theft” because it is easy for someone to access a random, external hard drive into their own computer. Many people today use a finger print or password to access to their hard drive because of this reason. Without a hard drive, one could not store the countless amount of information contained to a computer. The hard drive holds a port to connect to the motherboard.[4] There are a wide range of capac- ity for hard drives, depending on the computer owner’s preference.[5] Magnetic hard drives and solid-state hard drives are two common hard drives used for computers. A magnetic hard drive is the term computer users mean when they say hard drive, and solid-state hard drives cause flash memory technology. Without hard drives, many in- formation and data would be lost and forgotten.
• Magnetic hard drive
2.12. HARD DRIVES 39
External hard drives
• Solid-state hard drive
Datawalker LA18
Hard drives are used as primary storage units to store most data and computer programs to operate on a com- puter. The two types of hard drives available for purchase are: internal hard drives, and external hard drives. There are many things to consider if you are a consumer seek- ing these storage devices. The internal hard drive, which can be included in the computer before purchase, is di- rectly connected to the motherboard, (A.K.A the brain of the computer), as well as other components inside the tower or casing of the computer/laptop. An external hard drive is commonly used amongst users who are either portably transporting data/programs from device to de- vice, or seeking extra storage space for their files. Ex- ternal hard drives can be very small, and convenient for traveling with data. There are multiple different options to explore while considering a hard drive: speed, consis- tency, and durability. The types of hard drives offered include either of the following: magnetic storage, optical storage, and electrons which use flash memory media.[6]
2.12.1 Disk Access Time
Disk access time is a measurement that calculates the amount of time it takes before for a drive to read and
Hard drive head
write data. Disk access time involves three major steps: seek time, rotational delay (or rotational latency), data movement time. Seek time is the amount of time it takes for the head to move to the disk to prepare for reading. Rotational delay is the delay that occurs when waiting for the disk to begin rotating. Data movement time involves the movement of data from the disk to memory of the computer or the movement of data from the memory of the computer to the disk. Maximum rotational latency is the time it takes for the disk to perform a full rotation excluding any acceleration time. There are two types of ways in which a disk rotates: constant linear velocity and constant angular velocity. Constant linear velocity occurs when the rotational speed of the disk is dependent upon the location of the head. Constant angular velocity oc- curs when the disk is spun at the same speed regardless of the location of the head, like vinyl records. Certain low-noise disks utilize a slower disk access time to reduce noise created by the hard drive. Slower rotational speeds and seek speeds are purposefully installed to make sure that audible clicks and crunching sounds don’t interfere with recordings.
2.12.2 Hard drive interface standards
A hard drive interface (or hard disk interface) refers to “the logical and physical means by which the hard disk connects to the PC.”[7] For over a decade, the most com- mon hard drive interface was by a wide margin AT At- tachment/ATA, also known as Parallel ATA or PATA. ATA is still used in modern PCs, but it is not as sig- nificant as the more modern interface, Serial ATA, or SATA. The more modern SATA uses smaller cables, is more reliable, and possesses greater bandwidth than the now-obsolete PATA. SATA and ATA are not compatible, but there exist adapters to connect ATA interfaces with SATA drives (or SATA interfaces with ATA drives). An- other common interface is SCSI (or Small Computer Sys-
40 CHAPTER 2. HARDWARE
A hard drive with a SATA interface.
tem Interface), which is especially useful for multitasking where multiple hard drives are used, such as in a work- place environment.[8] Essentially, the difference between these three interfaces can be summarized as follows:
• ATA interfaces are cheaper and are still fairly com- mon, but they are slower and outdated.
• SATA interfaces are the most useful: the only prob- lem is that you need to buy additional adapters for them to interact with older systems, but they are still relatively cheap, they have high speed, and their wires are small, which frees up more room in the computer and helps prevent overheating.
• SCSI interfaces are very fast and can handle a wide range of applications and amount of data, but they are quite inexpensive and impractical for home use; SCSI is used more for networks than personal use.[9]
2.13 Optical Discs
2.13.1 Characteristics
An optical disc is a flat, circular disc that stores data and is made out of a very strong plastic called polycarbonate substrate. This helps to protect the disc with many layers of coating. Data on these discs are read optically, which means that they store data using laser beams. Data can be stored on one or both sides of the disc. The track, which is a single spiral around the disc, spins from inside the cen- ter track (or groove) to the outermost track for the data to be read. Most people today have already switched from VHS movies to DVD movies, and now to Blu-ray DVDs. The advancement in technology has made viewing and
Optical Disc
burning capabilities for DVDs and CDs much more ben- eficial. These optical discs do not degrade, like VHS and magnetic media do. Optical discs are used in our every day lives for storage, backing up, photos, movies, music, and much more. Read only discs are molded and stamped to show the data so that it can only be read (and not over written). This happens with most CDs for music and software, and DVDs for movies. A recordable or rewritable optical disc with a CD or DVD uses a laser to represent the data. An example of this would be burning a CD for music, or an iMovie project to a DVD. There is a complex process that takes place when writing the data on the optical disc. To mold or stamp the discs, bumps (called pits) are formed on the disc’s surface. The places that are not changed on the optical discs are called lands. Switching from a pit to a land represents a 1 (like discussed in the system unit). CD discs use infrared lasers, DVDs use red lasers, and Blu-ray discs use blue-violet lasers. These different types of lasers are used to store different amounts of data at a more compact size. Optical drives are the machines that read the discs of CDs, DVDs, and BD drives. Many households have switched to Blu-ray DVD players. However, users are upset because only BD discs can be played on BD drives which is considered a hassle to some. These drives are also used to burn data on the discs.
2.13.2 History
Optical disks were invented in 1958 by David Paul Gregg, he patented them. James T. Russell was then the first per- son to have made a recording audio digitally to an optical disk. Later Sony and Phillips research physicists made the CD’s we know today that can store large amounts of
2.13. OPTICAL DISCS 41
Gnome-dev-removable
data. For this first generation of CD’s they could hold up to 75 minutes of audio with 650Mb of storage. The pur- pose of the first generation was only for audio and com- puter software. They were capable of making a CD video but the VHS cassette was more popular at the time and it cost too much to produce them. These CD’s were read with an infrared laser. Later the second generation could store even more data and was used for video. They were read with a visible laser light which allowed the lands a pits to be smaller thus creating more space to for more data. They allowed 4.7 GB of storage on a standard sin- gle disc. The third generations are being developed to create even more storage available, like a Blu-ray disc. The Blu-ray disc use blue-violet lasers. There is even a fourth generation to be discovered that could hold up to one terabyte of storage.
2.13.3 CDs, DVDs, and BDs
Recordable CDs
Read-only optical discs include CD-ROM, DVD-ROM,
and BD-ROM discs. These are CDs or DVDs that come with something already prerecorded on them and they cannot be cleared. This is because the pits that are molded into the surface of the disc are permanent. There are also read-only discs for video games and different software.[10]
Recordable optical discs are also sometimes referred to as write-once discs. This means that these can be written to but the discs cannot be reused or erased. These include CD-R, DVD-R, DVD+R, and BD-R discs. The differ- ence between the DVD-R and the DVD+R is the standard being used. There is also a DVD-R DL and a DVD+R DL, which indicates whether or not it is dual layer. Using DVD+R will allow you to instantly eject the DVD without having to wait for the finalized version. It also allows you to record some of the DVD on a personal computer and some of it on the TV. Another feature is that is it 100% compatible with all DVD players. Recordable CDs are often used for backing up files, making music CDs, or sending large files to other people. BD-R discs are used for even larger back ups that need even more storage and they are used for high-definition multimedia files.[11]
Rewritable optical discs include CD-RW, DVD-RW, DVD+RW, and BD-RE discs. These can be written on and then erased and rewritten on. To rewrite on these types of discs they use phase change technology. So ba- sically the rewriteable disc is coated with a metal alloy compound. They then use heating and cooling to write on the disc without making it permanent. These are used for backing up files but they are more convenient than recordable optical discs because they can be used multi- ple times.
Details about CDs
Small cdisk ubt
Compact Disc (CD) is used to store video, audio, and data in different formats classified in the Rainbow Books. It includes formats like CD-ROM (Compact Disc Read-
42 CHAPTER 2. HARDWARE
Only Memory), CD-R (Compact Disc- Recordable), CD- RW (Compact Disc-ReWritable), VCD (Video Compact Disc), photo CD, and Enhanced Music CD. Compact Disc comes in standard 12 cm (120mm) or 8 cm (80mm) in diameter. The most popular is the 12 cm type with a 74- or 80-minute audio capacity and a 650 or 700 MB (737,280,000 bytes) data capacity. The 8 cm type is used in electronic devices like portable compressed digital au- dio players or data storage products like miniature CD recorders.[12] CD-Rs were invented by Philips and Sony and together with CD-ROM there were about 30 billion CDs sold worldwide in 2004. The high-capacity record- able CDs can hold 90 or 99 min of audio on a 12 cm disc and 30 minutes of audio on a smaller disc (8 cm). The ability to write beyond the manufacturer’s declared capacity on a CD-R or CD-RW disc is called oversiz- ing or overburning. However, Overburning might affect product warranties and result in lost data so it is not rec- ommended. However, it might affect product warranties and result in lost data so it is not recommended.[13] These days, more and more compact discs are being replaced by flash drives or downloading.
Details about BDs
Blu-ray disc (BD-RE)
The newest form of optical disk is the Blu-ray disk (BD), which was officially announced on February 19, 2002, and was first available to consumers on April 10, 2003. Blu-ray gets its name from the blue laser that reads it (as opposed to the red laser that reads DVDs). BDs have more storage capability than its predecessor and also has a variety of new functions that DVDs did not have, such as the following: record high-definition television with- out losing quality, record one program while watching an- other at the same time, automatically search for an empty space on the disc to avoid recording over a program, and access the Web to download subtitles and other features. The way BDs achieve this is by having smaller pits, so
more data can be stored, and having a laser with a shorter wavelength, a blue laser, that can read more precisely. DVDs could not fit more information because a red laser is not precise enough to read pits that are packed together as close as the pits on a BD. Pits on a DVD could be a minimum of 0.4 microns, while BDs pit minimum is 0.15 microns. Also, the track pitch on BDs has been re- duced from 0.74 microns to 0.32 microns. Because of all these improvements, a BD can hold more than 25 GB of information, which is five times the amount that a DVD can hold.[14]
Xbox360 scratch
How to Repair a Scratched CD or DVD Compact Discs (CDs) and Digital Video Discs (DVDs) both store their data externally on a disk. Unfortunately, as we all have experienced, these disks often times get scratched, making the CD or DVD skip, or sometimes not work at all. Depending on where the scratch is located, the disc may or may not be able to be repaired. It seems scratches on the top, shiny part of the disc are harder to repair than if the scratch is on the lower plastic part of the disc. Al- though some companies are developing scratch resistant discs, their efforts may be in vain due to technology mov- ing fast past these forms of storage. For those people still utilizing CDs and DVDs, scratches on them can be an- noying and frustrating. There are a few simple remedies consumers can try to repair their discs and attempt to get more life out of them. The first step is to clean the disc with a mild soap and water. This can help by removing any finger prints that may be hindering the disks’ func- tionality. Users then want to dry the disc with lint free cloth, as even the smallest fibers can scratch and damage the disc further. After the disc is dry, the user can then apply toothpaste to it, smoothing it out in a straight di- rection from the disc’s center. After this, the disc should be rewashed to remove any excess paste. If this proce- dure is successful, the toothpaste will fill in the scratches
2.14. FLASH MEMORY 43
so the disc can again be played with little or no skipping. Often times, scratches to these discs are too severe for this method to help. If that is the case, companies ad- vise consumers to discard the disc altogether. Luckily, as technology continues to advance, the reliance on these forms of storage is decreasing, and with it, the annoyance and frustration that comes from their malfunctioning.[15]
You don't need this anymore
Are Optical Discs Becoming Obsolete? While Opti- cal Discs may be excellent media of storage, their neces- sity has now come into question with the ever advancing of technology. Floppy disks used to be what everyone used to store information and that soon became obsolete. As the cycle of technology inevitably catches up to opti- cal discs, they may no longer be as useful as before. First, there’s the rise of technologies that no longer make use of optical discs because of the size. Most tablets and lap- tops no longer having optical drives because they take up space and may make the device less portable. Next is the fact that there are many more storage options that have become available that are much more convenient. Cloud storage has been on the rise as well as regular flash drives have had an increase in storage capacity as compared to optical discs. Then there’s the fact that many media com- panies have moved to a disc free environment. Stream- ing services have made renting CDs and DVDs obsolete. Gamers no longer buy physical discs but rather just down- load a digital copy. Even music has moved to a streaming service that makes buying physical albums and LPs more of a novelty. Finally, there is the fact that consumers want what’s convenient and optical discs are no longer as con- venient as they used to be. However which way you look at it, the advancement of technology will eventually make anything obsolete. The future holds many possibilities for other forms of storage and that too will eventually become obsolete.[16]
2.14 Flash Memory
Flash Memory and How It Works
Word Line 0
Word Line 1
Word Line 2
Word Line 3
Word Line 4
Word Line 5
Word Line 6
Word Line 7
Bit Line Select
Transistor
Ground Select
Transistor
Bit Line
N N N N N N N N N N N
P
Flash Memory Structure
Flash memory is a type of storage device that uses elec- tronic memory. Flash memory comes in a variety of ways and is known as a solid state storage device, meaning “there are not moving parts – everything is electronic in- stead of mechanical.” Flash memory is used in many dif- ferent devices, such as, computers, digital cameras, and mobile phones. Flash memory is a type of EEPROM chip. EEPROM stands for Electronically Erasable Pro- grammable Read Only Memory. Inside of a flash mem- ory chip is a grid of columns and rows with a cell. There are two transistors at each intersection and a thin oxide layer separates them. One transistor is known as a floating gate and the other one is known as the control gate. An electrical charge comes through the columns to the float- ing gate, which is called tunneling. The electrical charge causes the floating gate transistor to act like an electron gun. When the electrons get trapped on the other side of the thin oxide layer, closer to the control gate transis- tor, they act like a barrier between the two transistors. A cell sensor monitors the level of the charge. If the flow is above the 50% threshold, it has a value of 1 and if it is less, the value changes to 0. This is how information/data is being read on the flash memory device. Nowadays, flash memory has become the “dominant memory type wherever a system requires a significant amount of non- volatile, solid state storage.” [17]
Embedded Memory
Embedded memory is becoming an increasingly popular type of flash memory due to its small, convenient size. In today’s society these types of memory can be found in phones, cameras, gaming devices, and even handheld devices like a GPS.[18] In July 2013, Samsung announced that they developed the world’s fastest embedded mem- ory. These new products will be available in the 16, 32, and 64 GB sizes and feature an interface speed of
44 CHAPTER 2. HARDWARE
400 MB/s. This will increase user’s abilities to multitask and perform tasks such as file transferring, browsing, and gaming. It also decreases the amount of time it takes to boot and load applications. This is a key factor in mobile devices where the physical space for additional storage or memory is limited. Memory cards are being used less and less when manufacturing mobile devices and smart- phones. One limitation of the chip is the amount of mem- ory it could store. The larger the chip, the more expensive the device is going to cost. Something else to consider is the problem that arises if the device breaks. Any valuable information that was stored on it is virtually irretrievable. That is one advantage of having a removable memory as discussed below.
Flash Memory Cards and Readers
One of many different types of flash memory card that exists on the market.
If you want a fast and easy method of storing various types of media, you can't get much better than a flash mem- ory card. Most modern portable devices contain a flash memory card because of its versatility and ease of use; cellphones, mp3 players, and digital cameras are but just a few examples of products that benefit from flash mem- ory cards. However, just like how not all electronic de- vices can use the same type of battery, not all flash mem- ory cards are compatible with every electronic portable device.[19] That’s why it’s always important to read your user manual for instructions on the right card to purchase if you ever need a replacement. Although the devices themselves can only use a spe- cific flash memory card model, most modern desktop and notebook computers come with a flash memory card reader. The reader typically supports a number of differ- ent cards so you're able to organize and transfer the data from card to computer. If you aren't one of the fortunate few to have this reader built in to your computer, external models are sold at most stores that sell computer compo- nents and they're inexpensive. Although a general-purpose flash memory card is used for most applications, there are other special memory cards
Sony PlayStation Memory Card, made for gaming purposes only.
that are made only for one unique purpose. For example, a professional compact flash memory card is designed for professional photographers for improved speed, quality, and storage capacities, taking telling a story through a pic- ture to the next level. Also, special gaming flash memory cards are used for all game consoles, like Nintendo Wii and Sony PlayStation, to hold saved game data. Other special flash memory cards include HD memory cards for capturing high-definition videos; netbook memory cards to expand the storage of a netbook computer; and Wi- Fi enabled flash memory cards used to wirelessly upload photos from a camera. [20]
USB Flash Drives
Sushiusb
The USB storage device is one that has been growing rapidly in popularity. It is a very user friendly form of storage. To save information to a USB flash drive, one simply must plug in the USB drive into the USB port (usually on the side or back of the computer), click the “save as” option on their project, then select the drive on their computer which represents the USB. Then one can eject the USB and take the saved information anywhere
2.15. OTHER TYPES OF STORAGE SYSTEMS 45
they need. USBs are quickly advancing as well. There are now ways that you can create an entire mobile com- puter, a fingerprint enabled secure file, and secure the use of your computer all with the use of a single USB flash drive. These new advances are sure to be hot on the mar- ket. USBs are high in demand right now, not just because of their technical abilities but also because of how you can choose a USB to fit into any lifestyle or match any person- ality. There are thousands of custom USBs available in stores and online. These range in colors, sizes, amounts of memory, and even shapes.[21] USB flash drives are some- thing that will definitely be here to stay for a while longer, even with the ever emerging cloud. USB flash drives are also very secure ways to store information. Since they are not connected to the Internet, they cannot be hacked, and some can be encrypted to prevent unauthorized access. The one down side to this use is the possibility of the flash drive being lost or stolen, but with proper precau- tions and organization, this can be avoided. Flash drives also preserve data and documents in a non-volatile state. As some specialized computers (such as theatre control boards) are prone to crashes and glitches, saving infor- mation on a flash drives prevents is from being corrupted or lost in the event of a system crash or other glitch. In simpler systems, flash drives can be used as the central storage point for a computer. While this may be ineffi- cient on most machines, those that are single use and do not require large amounts of memory can benefit from this, as the system is flexible, and more memory space can be added as needed. However, the primary benefit of flash drives remains the mobility. Flash drives are an inexpensive and more secure alternative to the cloud and other means of Internet storage.
USB flash drive
USB drives are the perfect devices for transporting data and files. They are easy to use and their portability makes them incredibly convenient. In addition to storing files, they can also be used to run portable apps. Certain ap- plications can be turned into portable versions of them- selves. You can have access to various software appli- cations to use on any computer. Free programs exist to convert applications to portable ones to, in essence, cre- ate a portable PC on a thumb drive. USB drives range in storage capacity from 2 GB to 256 GB. With 256 GB of storage in such a portable size, the limits to their use are virtually endless.
USB drives can be password protected, or some can even be secured using biometric features, like a finger print. There are some concern related to USB drive security. They can contain large amounts of information, and given their portability, they can be used for transporting files secretly. Anyone with access can simply plug a USB drive into a computer, copy files onto it, and remove them from the premises. USB drives carry an additional security risk in that they can contain malware that can be launched using AutoPlay as soon as they are plugged in. http://www.howtogeek.com/203061/don%E2%80% 99t-panic-but-all-usb-devices-have-a-massive-security-problem/
2.15 Other Types of Storage Sys- tems
SAN NAS
N AS
CL IE
N TS
BL O CK
ST O RA
G E
N ET
W O RK
FI LE
SE RV
ER S
FiberChannel, iSCSI, or AoE SMB, NFS, AFS
Network Storage
2.15.1 Remote Storage
Remote storage is there to expand the disk space without hard disks and isn’t connected to the computer directly but accessed through internet. That way you can access your files wherever you are, whenever you want, on your laptop or Smartphone or even a different computer. This is the basic concept of cloud storage. When you need to access a file, you open the file as usual but if the data isn’t on your local volume, Remote Storage retrieves the infor- mation from a media library. When data is removed from a file, the logical size of the file remains but the physical size is reduce. [22]
Being much faster and reliable than storage devices like CDs, DVDs, hard disks, and flash drives, an online re- mote storage provides protection against system errors like viruses, and enables one to recover lost data from any potential system crashes. Being critical to not only businesses, but home computer users as well, an online storage provides low-cost and easily accessible security for data management and storage. To assure maximum security, many online companies automatically backup systems on a daily, weekly, or monthly basis, to an “elec- tronic vault.” Also, unlike CDs or DVDs, using remote storage diminishes its vulnerability to damage and data
46 CHAPTER 2. HARDWARE
loss. Living in today’s high-tech society, the online re- mote storage system is definitely a very essential, yet af- fordable tool to assure that the countless amounts of data being saved on devices is still remediable after a com- puter failure. [23]
2.15.2 Holographic Storage
Detector
Gating light
Laser
Beam splitter
Mirror
Shutter
Crystal
Holographic Data Storage
Holographic storage utilizes photo-sensitive media and innovative laser beam technology as a means of computer storage. This is unlike previous methods of data record- ing, such as magnetic and optical hard drives, which in- volve a rotating disk or simple 2D lasers. Instead, holo- graphic storage begins with a single laser that is split into two separate parts -- the signal beam (carries data), and the reference beam (reconstructs hologram when prompted). A spatial light modulator is used to encode data for the signal beam, followed by a conversion of elec- tronic data into binary code. It is then arranged into a specific pattern of dark and light pixels (representing ze- ros and ones), consisting of >1 million bits each. The signal and reference beams intersect, and a holographic image is created through a 3D refraction that is etched into the media. Advantages include a safe, fast, reliable, and portable system of storage. Disadvantages include expense, limited capacity, and recording fails. Since the concept is still in its infancy, however, problems are ex- pected to diminish greatly over time. [24]
2.15.3 Storage area network
Storage area networks are clusters of high performance computers used to transfer huge amounts of data. SANs are also used for distributed processing applications re- quiring fast local network performance and designed specifically for data management. SANs move storage resources off the common user network and into an inde- pendent network. What this does is allow each server too access any shared storage extremely quickly, as if it was already attached to the server. Typically, a SAN is assem- bled using three components: cabling, host bus adaptors, and switches. [25] [26]
The storage cloud enables storage devices like a PC, a desktop, or a mobile phone to communicate with the host computer system, as well as with each other.
What makes a good storage area network? A SAN defi- nitely needs to be indestructible and have a built-in pro- tection against any potential harmful failure. If a SAN is vulnerable to failures and is unable to recover lost data, an enterprise may even go out of business! Secondly, a vast amount of storage capacity is another essential to a valu- able storage network; since the number of devices con- nected to one host system may increase by time, the or- ganization’s storage and processing also needs to expand accordingly. A big advantage of using a good storage area network is the fact that even if all of one’s system servers crash, the SAN remains online and provides disaster re- covery. [27]
2.15.4 Network Attached Storage
NAS is a type of dedicated file storage device typically connected by a wired networking connection, therefore only providing local area network users with storage. NAS supports file transfers, in which it will back up any data that appears in the form of files, such as email boxes, web content, remote system backups. The main advan- tage of a network attached storage is that network storage is no longer limited to the amount the computing device can hold. NAS devices typically look very box-like, with- out a keyboard or display. NAS products come in levels of capable storage space, drive capacity and drive scal- ability, often placed into one of 3 categories: Desktop NAS, devices aimed at small businesses and home users; Mid-market NAS, devices capable of running several hundred terabytes but not clustering; Enterprise NAS, de- vices that can store huge amounts of files, including vir- tual images, and being able to NAS cluster. [28] [29]
2.15. OTHER TYPES OF STORAGE SYSTEMS 47
NAS
2.15.5 NAS vs SAN and Cloud Storage
Both systems of storage serve different purposes for their clients. The main difference between SAN storage and NAS storage is the way that the systems interact with the network. A NAS network will behave in a way that makes it similar to any other network component. In contrast, the storage devices of a SAN network are found in a sep- arate network but connected to the main one. Overall though, both systems are used for storage and over time the performance offered by both is becoming harder to distinguish. For example a SAN uses Fibre Channel in- terconnects while NAS makes Ethernet and TCP/IP con- nects, but now many SAN systems are switching over to those connection routes NAS systems use.[30]
Cloud storage, sometimes just called online storage, is simply the use of a remote storage device that is accessed by means of the internet. Cloud storage has seen a mas- sive increase in popularity over the last few years, and the industry for it has grown substantially to the point where there are now hundreds of companies that offer a vari- ety of cloud storage services. More specifically, some cloud services focus only on digital pictures or email mes- sages, while other systems store all kinds of digital data. Some services, like Google Drive, allow users to save
Sharing via “The Cloud”
their files in one of many massive data centers Google op- erates where, for instance, multiple users can collaborate on projects by having access to the same file.[31]
As the cloud’s popularity is growing, more and more busi- nesses are transferring over to its storage capabilities. Many businesses are using the application as a back up program for their software and documents. By scheduling a set time for the computer to automatically transfer doc- uments over, businesses can be sure that their information lies safely in the hands of the Internet without having to spend the tedious amount of time backing it up manually. Though the different applications of the cloud do some- times have a monthly fee to pay, it is a small price to pay for the time and convenience it lends you. By utilizing these applications, anybody is able to access their doc- uments anywhere worldwide. An individual is no longer tied down to just one electronic device in one set area, but can instead revise a version of a document on their laptop and then pull it up at work for a presentation the next day. This is just one example of the hundreds of ways that the application can be used conveniently to meet your day- to-day needs. The cloud is connecting electronic devices all across the globe and making every day processes just a little bit easier. [32]
Despite of the fact, that a Cloud storage term has ap- peared in use quite recently, people and businesses ac- tuality use online storages for a long time. For example saving copies of letters on mail server or retrieving net-
48 CHAPTER 2. HARDWARE
Cloud Services
work configuration files from TFTP server. These days Cloud storage term should be considered is one of many other Cloud computing services. It could be provided as separate product – “Storage-as-a-Service”, and also be a part of others, for example: Infrastructure-as-a-service, Platform-as-a-service or Software-as-a-service. As was mentioned above, the rapidly growing popularity is pri- marily due to quite low cost for a service itself (Storage- as-a-Service) when users pay only for the volume of data they stored, and if we are talking about the Infrastructure or Platform services which are great opportunity for busi- ness to reduce an IT expenses as well. With all advantages are given by online storing, there are few things users should be aware deciding entrust the care of their data to the provider. It might be as purely technical concerns (re- liable internet connectivity, provider’s backup algorithm, disaster recovery, security of access, etc.) and legal as- pects as well (ownership of data, jurisdiction, rights to audit). [33]
2.15.6 Smart Cards
Back of a smart card
A smart card is a credit card-sized piece of plastic that contains computer circuitry, like a processor, memory, and storage. Smart cards can only store low amounts of data, around 8 kilobytes of RAM or 346 kilobytes of ROM. The processor is actually a microprocessor, and it is situated under a gold contact pad on one side of the card. The processor in the card has the capability to en- crypt the data so that only authorized access is allowed. The purpose of a smart card is to store sensitive data securely, usually identification or digital cash. Unlike a credit card where all of the information on it can be read easily and identity theft is more common, the smart card cannot be physically read and it puts up a difficult fight against a hacker trying to access the data. To make it even more secure, some smart cards actually store bio- metric data to even further ensure that only the correct user can use it. A smart card is used by sliding it through, placing it in, or placing it in front of a smart card reader. This allows for the smart card reader to interact with the smart card by transferring the data on the card. An ex- ample of this is having a smart card reader on a locked door. The authorized user, a government official, places their smart card in front of the smart card reader on the door and the data on the card would be read by the reader. Once the reader acknowledges that the government offi- cial is allowed in, the reader would unlock the door and the official could walk in. All in all, the smart card is a great new technology that is making transactions and equipment safer.[34]
2.15.7 Large Computer Storage Systems
The original storage system for major company Walmart
Major companies and organizations require large com- puter systems that can store their massive amounts of data. The amount of data that the world needs to store is growing at a phenomenal rate, predicted to increase by half in 2014 alone. Regulations have been put in place by the government to make companies keep data and infor- mation about clients and customers. This information is stored in the same types of hardware that everyday con- sumers would use but on a much larger scale. Many hard
2.16. REVIEW 49
drives are connected and used together to increase the amount of data that can be saved. A leader in the industry, IBM, is currently at work on the largest storage server ever with an incredible 120 petabytes of space. This server is going to be comprised of over 200,000 standard hard drives connected in a large warehouse.[35] Some compa- nies may also use a system called RAID, or redundant ar- rays of independent disks. This method uses two or more hard drives which contain redundant copies of the same data in order to process and access it faster. This can be done one of two ways. The first method, disk striping, actually separates and spreads the files out over multiple hard drives while the second method, disk mirroring, has an exact duplicate of the information on the first.
2.16 Review
2.16.1 Review Questions
1. True or False; A magnetic hard drive uses flash mem- ory. 2. True or False; A Blu-ray disc offers a larger storage capacity than a DVD disc. 3. True or False; Folders are places on a storage medium that hold files. 4. True or False; Holographic storage uses lasers to pro- duce three dimensional representations of data. 5. True or False; NAS and SAN technologies refer to the same type of storage setup. 6. A _____ is anything that is stored on a storage medium. 7. A _____ _____ _____ is a type of flash memory device that is inserted into a USB port. 8. Music and software typically use a _____ disc. 9. Most computers use a _____ _____ as the primary storage system. 10. A drive that uses optical discs is known as an _____ _____. Answers 1. False 2. True 3. True 4. True 5. False 6. file 7. USB flash drive 8. CD 9. hard drive 10. optical drive
2.16.2 Glossary
• BD-R a Blu-ray disc that is recordable
• BD-RE a Blu-ray disc that is rewritable
• BD (Blu-Ray disc) a disc with a high storage capac- ity of approximately 25 or 50 GB. Commonly used in HD movies
• CD a disc with a low storage capacity of approxi- mately 650 MB. Commonly used in music and soft-
ware
• CD-R a CD disc that is recordable
• CD-ROM a CD that can only be read from but not able to write over
• CD-RW a CD that is rewritable
• cluster a sector that is the smallest addressable area of a disk
• cylinder a collection of hard drive tracks
• disk access time how long it takes to locate and read data from some storage medium
• disk cache memory that improves the time it takes to read from or write to a hard disk
• DVD a disc with a medium storage capacity of ap- proximately 4.7 GB or 8.5 GB. Commonly used in software, movies and games
• DVD-R/DVD+R a DVD that is recordable
• DVD-ROM a DVD that can only be read from but not able to write over
• DVD-RW/DVD+RW a DVD that is rewritable
• embedded flash memory flash memory chips used in products
• file anything stored on a storage medium
• filename the name given to the file
• flash memory nonvolatile memory that can be found in a computer or used in a storage medium
• flash memory card a flash memory medium often found in digital cameras and other small devices
• folder a named place on a storage medium where files are kept
• hard drive a storage system found in most comput- ers
• holographic storage a medium that stores data in three dimensions using multiple blue laser beams
• hybrid hard drive a hard drive with both flash memory and magnetic components
• magnetic hard drive a hard drive with one or more metal magnetic disks, an access mechanism and read/write heads
• magnetic tape storage media that stores data as a series of magnetic spots
• network attached storage (NAS) a high- performance storage device individually connected to a network to provide storage for computers on that network
50 CHAPTER 2. HARDWARE
• online storage remote storage devices accessed via the internet (i.e. cloud storage)
• optical disc a storage medium that reads and writes using a laser beam
• optical drive a drive used with optical discs (e.g. CD, DVD, BR)
• RAID (redundant arrays of independent disks) the configuration of several hard drives working to- gether to improve performance and/or reliability
• remote storage a storage device that not directly connected to the computer that uses it (e.g. cloud storage)
• sector a small piece of a track
• smart card a small card-sized circuit piece that can store data
• solid-state drive (SSD) a hard drive that uses flash memory (rather than metal magnetic hard disks)
• storage area network a network of hard drives or other devices that provide storage for a computer network
• storage device hardware in which a storage medium is inserted to be read from or written to
• storage medium the part of a storage system where the data is stored (e.g. CD)
• track a circular path on the surface of a disk where data is recorded
• USB flash drive a storage device, that uses flash memory, that is inserted in a USB port
2.17 References [1] https://www.inkling.com/read/
dummies-comptia-aplus-clarke-tetz-3rd/chapter-5/ understanding-hard-drive
[2] http://kb.sandisk.com/app/ answers/detail/a_id/8150/~{}/ difference-between-sequential-and-random-access-operations
[3] http://www.dineshbakshi.com/igcse-gcse-ict/ storage-devices-and-media>
[4] http://www.computerhope.com/jargon/h/harddriv.htm
[5] http://it.med.miami.edu/x929.xml
[6] http://www.pcmag.com/article2/0,2817,2404258,00.asp
[7] https://www.ifixit.com/Wiki/Hard_Drive_Interfaces
[8] http://www.newegg.com/product/ CategoryIntelligenceArticle.aspx?articleId=209
[9] http://www.adrc.com/interfaces.html
[10] http://www.thefreedictionary.com/compact+disc+ read-only+memory
[11] http://netforbeginners.about.com/cs/multimedia/a/ DVD_explained_3.htm
[12] http://www.osta.org/technology/cdqa7.htm
[13] http://www.osta.org/technology/cdqa7.htm
[14] http://electronics.howstuffworks.com/blu-ray1.htm
[15] http://electronics.howstuffworks.com/ how-to-fix-scratched-dvd.htm
[16] http://compreviews.about.com/od/cddvd/a/ Death-of-PC-Optical-Drives.htm
[17] http://computer.howstuffworks.com/flash-memory1. htm
[18] http://smithsonianchips.si.edu/ice/cd/MEMORY97/ SEC11.PDF
[19] http://www.pcmag.com/article2/0,2817,2388408,00.asp
[20] http://www.newegg.com/product/ CategoryIntelligenceArticle.aspx?articleId=220
[21] http://www.usbgeek.com/search?q=USB& search-button.x=0&search-button.y=0
[22] http://technet.microsoft.com/en-us/library/cc759742(v= ws.10).aspx
[23] http://www.spamlaws.com/online-remote-storage.html
[24] http://www.vibrant.com/blog/holographic-storage-101. html
[25] http://searchstorage.techtarget.com/definition/ storage-area-network-SAN
[26] http://compnetworking.about.com/od/networkstorage/g/ storage_san.htm
[27] http://www.snia.org/education/storage_networking_ primer/san/what_san
[28] http://compnetworking.about.com/od/ itinformationtechnology/l/aa070101a.htm
[29] http://searchstorage.techtarget.com/definition/ network-attached-storage
[30] http://compnetworking.about.com/od/networkstorage/f/ san-vs-nas.htm
[31] http://computer.howstuffworks.com/cloud-computing/ cloud-storage1.htm
[32] http://www.theguardian.com/media-network/ media-network-blog/2013/jun/19/ how-businesses-using-cloud
[33] http://www.thesecurityadvocate.com/2013/03/20/ cloud-service-contracts-breaking-down-the-all-important-service-level-agreement-sla/
[34] http://computer.howstuffworks.com/question332.htm
[35] http://phys.org/news/ 2011-08-petabytes-ibm-largest-storage-array.html
2.19. KEYBOARDS, POINTING, AND TOUCH DEVICES 51
2.18 Input and Output
2.19 Keyboards, Pointing, and Touch Devices
Keyboards
Keyboards are one of the many different types of input devices, and one of the most common. Most if not all keyboards are set up in an alphanumeric key arrangement, also referred to as a qwerty keyboard.[1] There are a few different ways a keyboard can connect to a computer, ei- ther wired or wireless, via USB or Bluetooth respectively. For the most part all keyboards are similar to one another, some may have extra keys for games and others may have a numerical keypad built into the board itself.
Logitech Gaming-Keyboard G15
While not all computing devices have keyboards they do have supplements, such as a on screen touch keyboard. Many phones have a slide out keyboard for those who prefer an actual physical keyboard. Speaking of phys- ical keyboards, many tablets allow you to purchase a keyboard dock. All of these additional keyboards that you could add to devices are most likely membrane key- boards. Membrane keyboards are the cheapest and most common types of keyboards. The other growing type of keyboards are mechanical keyboards. When you type on a membrane keyboard you complete a circuit which pro- duces the data on screen, which generally makes little to no sound and gives no tactile feedback. For many gamers and avid typist, they would use a mechanical keyboard, which has the point of contact directly beneath the each key. This gives a better tactile feedback along with a faster typing speed, but generally cost much more than membrane keyboards.[2]
keyboard is most importent part of computer
Different Types of Keyboards The purpose of all key- boards is to input data, however, there are as many dif- ferent types of keyboards as there are variations of de- vices that need one. At first, there was only one design for a keyboard, but just as all other technology has pro- gressed with time, so has the keyboard. The “original” keyboard, known as the standard keyboard, is the QW-
ERTY keyboard, which is probably the most familiar to people. This keyboard has an average 105 keys, and while minor changes have been made to the design, its overall format has stayed the same.[3]
Microsoft Natural Ergonomic Keyboard 4000
Due to the stress put on the wrist and hand muscles from typing, the ergonomic keyboard was invented. This key- board has the keys split so that the angle of the user’s wrist is in a more comfortable and less-straining position. By improving posture, the Ergonomic Keyboard is supposed to prevent Carpal Tunnel Syndrome. It comes either as one separate board with pre-angled keys, or as two sep- arate boards so the user can angle them any way he/she prefers.[4]
The other types of keyboards that have come along have been produced to fit very specific uses. For example, a gaming keyboard, as the name suggests, is made specif- ically for gamers and has special designs such as built- in joysticks. Another example is the internet keyboard, which have “hot keys” related directly to browsing the in- ternet. These hot keys include bookmarks list, e-mail in- box, Google search, and YouTube.[5]
Lastly, there are keyboards made simply to be more con- venient for the consumer. These include the wireless key- board, which connects to a computer via Bluetooth, the compact keyboard, made for laptops and other portable devices, and the virtual (or touch screen) keyboard which is found mostly on mobile devices and tablets.[6] The last one is the most recently developed and will most likely come to be the only type of keyboard in the future.
The History of Keyboards The first keyboards were called QWERTY keyboards named after the six letters in sequential order on the top left hand side of the key- board. Surprisingly, the keyboard was actually designed to make typing as slow and difficult as possible. This is due to the fact that the very first design of the first typing machine developed by a man named Christopher Latham Scholes back in 1873 was originally set up in alphabeti- cal order. After some time, it was typical for keys to get jammed together due to fast typing. This prompted Sc- holes to redesign the machine with the letters most com- monly used as far away from each other as possible to avoid jamming. By making the user slow down, his new
52 CHAPTER 2. HARDWARE
EarlyComptometerKeyboard
design became a success. It wasn’t until the 1960’s that a couple by the name of Bob and Joan Crozier came up with the idea that there was a need to integrate computer technology into business. At that time, there were only large mainframe computers available. The couple came up with a device that had keyboard switches, which led to more understanding about the growing need for such a device. By the 1970’s, the first keyboards were born. They had to be put together one switch at a time which was a lengthy process. Later in this decade, the first ever personal computers were developed. The keyboard was not attached to these computers so they required an IBM electric typewriter to be attached. By the 1980’s, IBM launched its first personal computers with their famous model M keyboards attached. This model came with some problems as it was criticized for its Enter and Shift keys being too small. IBM came up with keyboard ex- panders to fit the keyboard and enlarge the keys. By the 1990’s, Membrane switches became available to replace individual keys. This was also the decade that the laptop computer became available, making Membrane Switches to increase in popularity. The last decade has seen ad- vancement in the design of the keyboard with the release of ergonomic keyboards that lessen the chance for a user to be injured due to overuse. Today, the modern key- board faces extinction as the use of touch screen devices and voice recognition are taking the center stage of com- puter input.[7]
Point and Clicks
Pointing devices are inputs that connect to a desktop or laptop and are used to move an on-screen pointer, usually an arrow, to allow the user to select objects on the screen. The most common of these is the “mouse” which derives its name from its size, shape, and “tail”, or thin wire, which connects it to the computer. It’s usually connected via a USB port and it often rests next to the keyboard for
Inside a Wheel Based Mouse
easy access. Recently, laser “mice” have become popular due their added mobility as these connect via Bluetooth or other wireless connection and and no longer need their “tails” for support to the system. Older mice have a ball at their base and use this to move the pointer on screen as the user’s hand moves the mouse across the desktop sur- face. Once the pointer is over the desired icon, link, or image, etc. the mouse is used to interact with it by click- ing one of the two buttons on it’s surface. A wheel may also be found on some and is commonly used to scroll up or down a page or zoom in and out of a window. Opti- cal mice use a laser on the bottom which track movement with light instead of a ball. Three dimensional mice may also be used to interact with three dimensional programs. These programs tend to recognize more complex move- ments and the mouse may be lifted to simulate flying or angled to simulate a visual tilt within the program.
Stylus
stylus pens
Instead of using a mouse for a computer many systems allow there to be used a pen or stylus. The pens input could be drawing, writing, or tapping on the screen. The
2.19. KEYBOARDS, POINTING, AND TOUCH DEVICES 53
stylus often is just a piece of plastic and is just used to touch the screen and that’s it. The stylus could detect the amount of pressure that is applied to the screen that would allow you to have a more exact input. The stylus have a smooth rounded tip so it would not harm the screen it is used with, and could contain buttons so it could be sim- ilar to a mouse in that way and complete those type of functions. The stylus is used to be the most convenient like a pen a paper. Areas like photography, graphic de- sign, animation, industrial design, and healthcare are us- ing the stylus to aid to their profession more. There are even certain gestures that a pen can read to complete a task. Such as flicking the pen up could delete something, or print, or copy. The pens are beneficial for people with long nails, or are wearing gloves; nothing more annoying than having to take off gloves in the winter to have to use a touch screen device.The Galaxy Note 3 has a pen sty- lus that it comes with. This phone allows the user to use the screen to its fullest since the screen is so large, the phone embraces being able to use two hands while doing something on the phone.[8]
Touch Screens
Interactive table, Ideen 2020 exposition, 2013.
Touch screens are electronic visual displays which allow a user to interact with programs by using simple touch- based movements. Through the use of a special sty- lus/pen and/ or one or multiple fingers, the user can inter- act with the content being displayed in multiple ways al- lowing actions such as scrolling, zooming, rotating, drag- ging, and dropping items to be handled with ease with- out the need for a pointer or mouse. Because the touch screen interface can be used with practically any PC soft- ware and is useful in a variety of applications, mobile phones, tablets, desktops, laptops, and surface computers have taken advantage of this technology. It can be found in museums, consumer kiosks, newsrooms, automated teller machines (ATMs), medical field, etc. There are many touch screen technologies that have different meth- ods of sensing touch, such as resistive, surface acoustic wave (SAW), capacitive, infrared grid, infrared acrylic projection, optical imaging, dispersive signal, and acous- tic pulse recognition. They can recognize multiple inputs
allowing for more than one person to operate the device at the same time as well as verify and pinpoint multiple objects that are place on them or near. Systems that use a stylus can recognize the differences in pressure applied to the screen and may even contain buttons to aid in “right- clicking” on an object.[9] The stylus is one of the most popular accessories in the touch-screen age.[10]
Fingerprint Scanners
A popular security option, which is now becoming stan- dard on laptops and certain external hard drives, is finger- print scanners. Small “touch screens” are placed adjacent to keyboards (or in the case of hard drives, on top of the hard drive) to prompt users to use their finger print as a means of secure login. Until recently, such hardware was expensive and unreliable. This means of input has been adapted by certain companies to increase security measures and provide peace of mind to clients (often in the case of physical cloud security). This technology was science fiction until recently and it has caught on in gov- ernment use all the way down to the individual.
Other Pointing Devices
Joystick
54 CHAPTER 2. HARDWARE
Examples of other pointing devices can be seen in gam- ing. A popular pointing device in video games is the joystick. Joysticks are moved by hand to point to an on-screen object, such as a character, and then a button or buttons are pressed to execute an action, for exam- ple jumping. Gamepads are also examples of pointing devices, performing similar functions to the joystick but held fully in hand instead. Another example of a point- ing gaming device is a proprietary controller, such as the Wii remote. These devices are motion sensitive and re- quire the controller to point into a sensor, which will move accordingly with an on-screen pointer. A trackball is a pointing device consisting of a ball in a socket, similar to an upside-down mouse, that the user rolls with the thumb, fingers, or palm. Trackballs are commonly seen on CAD workstations for ease of use. Control buttons and wheels are pointing devices commonly found on handheld gam- ing devices or portable digital media players. For in- stance, on an ipod, the user can spin the wheel to scroll though songs, and then click on the desired track. Touch pads are generally rectangular pads that a user can slide a thumb or fingertips across. Tapping the touch pad ex- ecutes the same action clicking a mouse would. Touch pads are typically found on laptops and notebook com- puters. [11]
2.19.1 Specialized Pointing Devices
An ETC Ion Lighting Console. The control wheels are visible above the LCD screen
Depending on the device and applications being used, pointing devices can become quite specialized. Theater lighting boards have several different ways to input in- formation due to the vast amount of equipment they can control. These can vary from joysticks to the more com- mon control wheels. These wheels tell the lighting fix- ture to cycle between colors, change effects, and move on at x/y axis graph displayed on a screen. Besides light- ing boards, flight simulators can have numerous input de- vices, most of which are customized to do a certain task. A number of manufacturers build throttle quadrants and
aircraft yokes for use in home simulators. These devices can be set up in minutes, and mimic the movements of the actual aircraft controls. Airlines and colleges take this a step further, using immersive simulator that enclose the operator and mimic the movements of an aircraft in flight. In these simulators, the entire enclosure is one large input device, with each button and knob controlling some func- tion. In addition, and instructor has a workstation where they can input commands and load scenarios to test the person flying the simulator. The full motion simulators used by airlines to train flight crews are perhaps the most complicated computer input devices.
• A Saitek control yoke is being used to control the aircraft in the simulator.
• This type of enclosed simulator is fairly common in flight schools, and collegiate aviation programs.
• This is the flight deck of a full motion simulator, used by airlines for testing and emergency training.
2.20 Scanners, Readers, Digital Cameras
Flatbed Scanner
Scanners
A scanner is a device that copies a picture in digital form. After capturing the image, the data is transferred to the computer. People use scanners to store their hand held pictures in their computer, and one might scan a docu- ment for business, school, etc. The two main types of scanners are flatbed and portable scanners. A flatbed scanner is the most common type of scanner, and it is designed to scan flat objects. A portable scanner is de- signed for travel purposes.[12]
A sheet fed scanner is much like the flatbed scanner, only this may now be immobile and be used in stores to scan items on shelves. Optical scanners capture the image of a usually flat object and transfer it to a computer, much like flatbed scanners. In order to produce a better qual- ity image, as most people strive for in their printing, you
2.20. SCANNERS, READERS, DIGITAL CAMERAS 55
Drum scanner
need a higher resolution scanner. The resolution of a scanner is measured in dots per 12-inches, which makes sense because the more dots you have, the more color that shows up, producing higher quality scans. Along with the resolution of a scanner comes the quality, which can be edited and improved once the image is scanned. If the user wants an extremely detailed scan, the drum scanner is a great tool to make this possible. It uses a photomul- tiplier tube to scan on a glass cylinder and send light rays in three beams, making light and color change and pro- ducing greatly detailed images.[13] There are even apps on our phone that we can personally scan documents to have on-the-go. The problem with this, however, is privacy issues and the crisis of having your phone or any other device stolen which has scanned any personal informa- tion. While scanners are a tremendous help especially in businesses, it is important users be aware of the risks and use with caution. Although digital cameras are considered standard today, many individuals still have negatives from their days of using a film camera. This traditional film can easily be digitized using a specialized film scanner. Increasing the resolution will allow for higher quality reproductions of the images. [14]
Readers
Readers are designed to read the coding of different products. Readers are also called a “price scanner.” It is usually a hand held device that captures the bar- code on a certain tag, sticker, or twitter/facebook code. UPC (Universal Product Code) and ISBN (International Standard Book Number) are the two most famous bar- codes. Barcodes are essential for efficiency in different businesses.[15]
• An example of a barcode scanner
• UPC barcode
• ISBN barcode
Barcodes use lines to represent the numbers 0-9. They can be quite long, signifying a long string of numbers. These unique number combinations represent a variety information. Barcode readers interpret the bars in the code using reflected light or imaging technology. Once the bars are interpreted, the information that is tied to the number can be retrieved. The scanners can be stationary, like those found in stores, or portable, like those used by delivery services to scan packages.
• Portable Scanner
Example of QR code
RFID-stick
QR Codes and RFID tags
QR codes, otherwise known as quick response codes, are pattern display bar codes read by an imaging device, that enable a user to automatically scan and open to an en- coded hyperlink by using their “smart device”. QR reader applications on devices enable the user to access the hy- perlink. The hyperlink opens up to a URL on the user’s device, displaying an image, or website. QR codes are often used by companies to allow the most efficient, least expensive way of advertisement for their product, com- pany, event, website, etc. These codes enable a potential
56 CHAPTER 2. HARDWARE
customer or user to access their information with conve- nience. QR codes are also used in other aspects to iden- tify time tracking, item identification product tracking, as well as document management.[16]
QR Codes are an expansion on traditional barcodes. Tra- ditional barcodes are one dimensional, while QR codes are two-dimensional. Storing data both horizontally and vertically allows for a significant increase in combinations of information.
Example of a QR Code
“QR Code” is a type of matrix bar code originally created in 1994 by the Toyota Automobile Company. They were used during the manufacturing process in place of tradi- tional bar code labels, which offer significantly less room to store data and were frequently damaged. Since the rise of smartphones (and downloadable QR scanning appli- cations), they have experienced unprecedented growth in popularity and success from advertising/marketing, and have in a sense revolutionized these industries. QRCs save businesses money by offering an affordable and per- sonalized way to promote their goods or services. Perhaps most importantly, however, they have given customers everywhere an entirely new way in which to access in- formation, both quickly and conveniently. [17]
RFID codes, otherwise known as the Universal Product Code, in which the barcode is replaced by radio frequency identification tags, which allows communication between network systems that can track certain data or informa- tion. RFID codes are commonly used in our economy to- day in multiple different ways. In similarity to QR codes, RFID codes also allow a user efficiency time-wise as well as convenience-wise. Ways that RFID codes are used in our society consist of the following: inventory tracking, ticketing applications, mobile payments, as well as border security.[18]
Digital camera
Disassembled digital camera
Digital Cameras
Almost every American owns a digital camera to save their memories! Digital cameras are used to take a pic- ture, and these pictures are usually stored in a memory card. When purchasing a camera, it is important to know how many mega pixels the camera contains.For example, the higher the mega pixels, better the quality the picture will turn out. However, usually, the higher the mega pix- els, the more expensive the camera will cost. People en- joy cameras because the pictures are almost immediately accessible.[19]
Today, digital cameras are often found integrated into various mobile devices.[20] When it comes to smart- phones, the camera is often one of the most marketed features of the device. For instance, when shopping for a smartphone online, a website will often have an im- age that compares a picture taken by various competi- tor’s phones. The reason these cameras on smartphones are marketed to this extent is because they offer so many advantages to an average everyday consumer. A cam- era with the capability of snapping nice pictures allows someone to easily share daily activities to social media, scan barcodes at the grocery store, provide post-accident evidence for insurance, and so much more.[21]
While a digital camera can snap still images, a digital video camera can record videos. Although portable dig- ital camcorders are slowly becoming unpopular in the market, other types of these cameras are used every
2.21. BIOMETRIC READERS 57
Professional video camera
day.[22] For example, these cameras are often used by buildings for surveillance, television networks for broad- casting, and companies for video conferences.[23] How- ever, each type of camera used in these situations are different. Cameras used for security purposes are usu- ally able to operate remotely, and are often found to be smaller than other cameras so that they are more incon- spicuous. Television networks use expensive professional cameras which have many different function and are very high performance. Cameras used for video conferenc- ing are often webcam cameras. These cameras are small, usually portable, and can be integrated with a laptop.[24] Overall, the digital video camera is a useful tool in today’s society. One of the main appeals of digital cameras is the instant gratification of seeing the image immediately upon taking it. The instant gratification comes at a small price, how- ever, because there is a slight delay between the pressing of the button and the actual taking of the photograph.
2.21 Biometric Readers
A U.S. soldier using a biometric eye scanner.
Biometrics are objective, measurable, biological traits that can be used to identify somebody.[25] Biometric identifi- cation is becoming more and more common, and indi- viduals can be recognized by a computer based on ev- erything from their eyes to their fingerprints, from their voice to their face, from their unique body odor to the shape of their ear. Some uses of biometrics include fin- gerprint scanners to protect sensitive information stored in databases at places like nuclear power plants, biometric identification at borders and on passports, identification at nightclubs to ensure people who have been banned can't enter, and even at public schools to have stronger records of attendance and library book borrowing.[26] While bio- metric authentication is incredibly useful, there can also, obviously, be strong privacy concerns if their use is be- coming too common. However, an organization called the Biometrics Institute is seeking to not only advance the use of biometrics but also ensure that all privacy con- cerns are addressed as this kind of technology becomes more and more common, with a set list of privacy guide- lines that should be met whenever and wherever biometric identification is being employed.
2.22 Audio Input and Output
2.22.1 Audio Input
Audio input is when audio data is put into a computer. Usually the audio that people put into computers is voice or music. Voice input is when words are spoken into a microphone on the computer and they are translated into the digital form via the microphone. Many people will use a sound recorder software to store the voice in a file. One thing that is becoming better known is speech recog- nition systems. An example of speech recognition be- ing used is when you call a company and an automated voice recording answers and you speak to them and an- swer their questions and the computer is able to recog- nize what you are saying and take you where you need
58 CHAPTER 2. HARDWARE
Microphone used to input audio into a computer
to go.[27] Many phones have speech recognition software that allows the user to speak their text message or any- thing else into their phone and the phone can type the text for them. However these programs are not perfect and they usually require the speaker to talk slowly and clearly. One new technology that is being developed has to do with computers picking up noises the hard drive is making and detecting if there are any problems. One way to input music into a computer is to input it from a CD. They also have keyboards that can be plugged into the computer and the sound can be inputted into the com- puter. With that technology they can also show the sheet music that was played.[28]
Speech Recognition
There are many different ways in which speech recog- nition systems work. One type of system is a speaker- independent speech recognition software which works no matter the user. Another type of system is a speaker- dependent system in which uses training to analyze a spe- cific users voice. The system is then able to adjust to nu- ances in a persons voice and fine-tune the speech recogni- tion. Another system is voice-recognition systems which are very similar to speaker-dependent systems in that they are dependent upon the speaker, but instead, they mostly focus on who is speaking rather than what they are say- ing. These types of systems are primarily used in per- sonal security systems. Speech-recognition software is used to ease the users use of the computer and allow users the freedom of not having to use a keyboard or mouse to navigate through a computer system. Speech- recognition software can be used to perform many tasks including opening applications, making calls, calculat- ing the amount of teaspoons in a cup, and even finding the nearest Chipotle. Today, the use of speech recogni-
tion systems are greatly advancing due to their incorpora- tion in mobile devices such as Apple’s Siri and Windows Cortana. Also, speech recognition software has been in- cluded within the makings of cars due to regulations that require drivers to use hands-free devices to avoid distrac- tion from the road. [29]
Parc Asterix 22
Speech detection and speech analysis are being used in robotics and automatic translation, access control systems and education, but not only a human speech is a subject of recognition. The created sound recognition software has a great scientific and practical value. A broken win- dow, dolphin’s talks, faulty machinery unit, even flow- ing blood could be recognize due the sounds they make. Growing sound libraries and improving electronic equip- ment allows actively apply sound recognition technologies in areas such as industrial automation, home improve- ment, animal bioacoustics, medical bioacoustics and oth- ers. People use speech recognition to let computers un- derstand them and use computers for sound recognition to better understand the world. [30]
2.22.2 Audio Output
Audio Output-Speakers
Audio Output is exactly how it sounds. These are the sounds heard while working on a computer, that incor- porates voice, music, and other audio sounds. The most
2.23. DISPLAY DEVICES 59
common type of audio output device are speakers. These are used to hear video games, music from iTunes [31] or YouTube,[32] TV shows on Netflix,[33] Web conferenc- ing, and other types of programs. Most computers have the capability to add additional speakers for better sound quality. The speakers are usually included when the com- puter is bought. Other speakers vary in a broad span of prices. A subwoofer can be added to amplify the com- puter’s audio output. Subwoofer’s have low-pitched audio frequencies known as bass and are intended to strengthen the low frequency range of loudspeakers covering higher frequency bands.[34] They can be installed in automobiles and computers. For portable laptops and mobile devices, the speakers are built into the device. Some desktop com- puters have speakers permanently installed to the mon- itor. A unique example of audio output is a treadmill. Some treadmills have the ability to play music from an iPod or MP3 dock, which makes working out more en- joyable. With our rapidly growing and expanding market, recently many car companies have included headphone jacks, dock connections, or USB ports to connect an iPod or mobile device. These connections make it easier for the driver to listen to their own music from their iPod, instead of the radio or CD’s. Headphones can be used as audio outputs as well, instead of using speakers. Using headphones helps users not to disturb others around them (in a library or school).
2.23 Display Devices
Display Device Characteristics
Old Philips Television Set
There are many different characteristics of display de- vices. These include display colors, monitor styles, reso- lutions, video compatibilities, and the extra abilities these devices may have. Most devices today have color dis- plays but there are a few which still follow a monochro- matic color scheme. The Nook eReader is one of these devices.[35] There is also a difference in the type of mon- itor in the way it is illuminated. The older style devices
Glass tube
Anode
Heater
Heated cathode
Grid
Cathode Ray Tube
such as the large, clunky, heavy tv’s and computer screens are lot with cathode-ray tubes (CRT) and because the tubes take up so much room, the devices needed to be much larger. Today most of our devices are flat-panel displays. These displays use a chemical or gas reaction between two thin clear pieces of material to create their display; this is why they are able to be much thinner and lighter than CRT devices.[36]
Buyer beware, when buying a new device keep in mind that the monitors are measured diagonally. So that new 7” tablet you are looking at on amazon.com is 7” diago- nally from corner to corner. If you expect the 7” to be the width, you will be sorely disappointed by the smaller device you receive.[37] Keep in mind also that resolution is important. The more information that can be shown in less space, the clearer the image and higher the reso- lution will be. Video is input through a video card which holds the GPU inside of it. The video card is used to translate the video information into an image that will appear on the monitor of your device. It uses a fairly large amount of RAM to do so. There are many ways of connecting video devices to computers, and one of those actually allows the addition of extra monitors to an exist- ing computer allowing for double the screen space. Other interesting features of display devices include the ability to hold a charge (temporarily) on their own and become known as wireless, display images in 2D or 3D format, become much more mobile and even wearable (such as a virtual reality simulator headset), as well as register com- mands based on touch and motion (e.g. iPhone, iPad, Android phone, and most other “smart” devices today).
60 CHAPTER 2. HARDWARE
Data Projectors
With a data projector, this heartwarming picture can get a whole classroom teary-eyed.
While your computer has many talents and uses, some- times it might seem as if there’s not enough of it to go around. Let’s say that there’s a hilarious cat video on Youtube that you'd like to share among thirty of your best friends but there’s not enough room for them all to huddle close before your glowing monitor. Instead of splitting the viewing party up in groups, you can use a data pro- jector. A data projector lets you display what’s on your computer monitor onto a wall or projection screen.[38] The image is blown up so all your friends can now laugh in unison as the Youtube cat extends its paws in surprise. Even if you didn't know the name for it, chances are very high that you've encountered a data projector sometime in your life, especially if you attend public school. They can transfer data from computer to projection screen ei- ther with a cord or through a wireless connection. For those of you who like to share on the go, there are even portable projectors called pico projectors that can provide a lesser quality but more accessible presentation.[39]
Flat Display Devices
Flat display devices have become increasingly popular over the years because of their slim design and accessi- bility. Monitors today must be able to provide full color and gray scale, high efficiency and brightness, the abil- ity to display full-motion video, wide viewing angle, and a wide range of operating conditions.[40] Consumers to- day want these devices to be thin and light weight, be in- sensitive to magnetic fields, and not produce any x-rays. All of these attributes are not possible with the cathode ray tubes that are generally found in older televisions or monitors. There are electroluminescent displays, plasma display panels, vacuum fluorescent displays, and field- emission displays all being sold today. The first are used in industries and medical fields because of how durable they are under many temperatures. Plasma displays are usually used in televisions. Vacuum fluorescent displays
are used for low information displays like on appliances or small electronics. Liquid-Crystal Displays (LCDS)are the most commonly manufactured displays at this time.
Unlike the old TVs with a “fat” back, the newer LED TVs are much thinner and energy efficient.
Without even realizing it, we are constantly surrounded by items containing an LCD since they are much thinner and lighter than other displays. Laptop computers, dig- ital clocks, microwave ovens, watches, and many other everyday items all have an LCD. A liquid crystal display works by blocking light as it uses charged liquid crystals that are located between two glass sheets to light up the appropriate pixels using a backlight provided by fluores- cent lamps. Conveniently, LCD panels typically already contain those lamps at the rear of the display, hence the term backlight. However, to preserve more energy, to- day’s new technology has invented light emitting diode displays (LEDs), which are now replacing the fluorescent lamps that were previously used. LEDs are another flat-panel technology seen in many ob- jects around us like alarm clocks, Christmas lights, and car headlights, etc. An advantage of an LED over an LCD is that they are a lot thinner, have brighter images, color, and quality than an LCD, or even Plasma. Also, since an LED does not require backlighting from fluorescent bulbs, which have a relatively short lifespan, it tends to have a much longer lifespan. As fluorescent lamps burn out more quickly, LEDs are better to use for applications that require turning on and off frequently. Another ben- efit of LED monitors is the fact that they consume much less power compared to LCDs; LEDs actually consume almost half as much power than an LCD consumes! [41]
Color generation for an IMOD display
2.24. PRINTERS 61
A new flat-panel display technology is the interferometric modulator display. This display uses a reflective mem- brane and a thin-film stack, which sit on a transparent substrate, to reflect external light onto the display. The device uses the interference of light wavelengths to cre- ate the different colors necessary for color images. This new display technology is meant to be used for portable devices and new mobile phones. The reason for this is be- cause the display consumes a very little amount of power. By only using external light, the device would not need to continually backlight the display. In fact, the only time the display would need to consume power is when chang- ing the image. This allows for the image to stay open without losing any power for the device, something we all have to deal with everyday on our mobile phones. An- other plus for the IMOD display is that the images will stay clear even when in direct sunlight, because it is ac- tually using that sunlight for the image. This is definitely an advantage for anyone who has noticed how hard it is to use a portable device or mobile phone outside when it is sunny. The IMOD display technology is a very energy efficient technology that needs to be utilized in mobile phones and portable devices to help consumers with their issue over battery consumption.[42]
Video Adapters, Interfaces, and Ports
HDMI-Connector
The graphics processing unit (GPU) is the chip devoted to rendering images on a display device. Devices either have a video card or an integrated graphics component built directly into the motherboard or the CPU. The GPU is located in the video card or the graphics component of the computing device. This is what determines the qual- ity of the image that can be shown on a monitor. Video cards will usually contain a fan to cool the card. Video cards will either have a memory chip or they are designed to use a portion of the computer’s regular RAM as video RAM instead. Video cards contain between 256 MB and 2 GB of video RAM. The three most common types of interfaces used to connect a monitor to a computer are VGA (Video Graphics Array), DVI (Digital Visual In-
terface), and HDMI (High-Definition Multimedia Inter- face). These are the ports that can be found on a com- puter to connect it another device, such as a TV screen or a projector. Today, HDMI is used widely amongst major electronic companies like Toshiba, Sony, and Panasonic. This allows for high quality connection and single-cable capability to be used to interconnect devices not matter who manufactured the computer.[43]
Virtual/Augmented Reality Devices
Boy wearing Oculus Rift experiencing Virtual Reality
One of the recent advancements is that of Virtual Reality and Augmented Reality devices. These devices display information by immersion rather than by just displaying it on a screen. First, the distinction between Virtual Real- ity and Augmented Reality is that the former completely immerses the user in a different “virtual” environment while the latter adds or displays information to the current and existing environment. So while virtual reality brings you into a theatre, augmented reality brings the movie to your wall. Both of these are implemented through var- ious devices. There are head-mounted displays. These are displays that are usually worn by the user and are seen through in order to experience either virtual or augmented reality. Those that do virtual reality usually cover the eyes so that the user is completely blocked out of the real world and can be fully immersed in virtual reality. Those that make use of augmented reality are usually see through since the objects are displayed in the real world environ- ment. Then there are hand-held displays which usually only do augmented reality. These usually make use of the devices camera and screen in order to show virtual objects in the real world.[44]
2.24 Printers
Printers today can be divided into two main categories: impact printers and nonimpact printers. Impact printers (known as dot matrix printers) are the traditional printers
62 CHAPTER 2. HARDWARE
that actually strike the paper with ink. Their primary uses are for the production of business forms like packing slips and receipts. On the other side are nonimpact printers. These printers do not touch the paper like impact print- ers, and there are two common types: laser and inkjet. Laser printers use ink powder and inkjet printers use ink, which both create the images with dots (similar to pixels on a monitor). These dots make up the print resolution, which is known as the dpi (dots per inch). The higher the resolution the sharper the image. General ranges for a dot matrix printer are 60-90 dpi, an inkjet 300-720 dpi, and a laser printer 600-2400 dpi.[45] With that, color print- ers and black-and-white printers are two standards found in either the home or office setting. Typically for home- use color printers are more common than offices, which will use black-and-white printers due to costs (unless the company needs color for specific materials and products like reports or brochures). Advantages of laser printers include higher resolutions of the image, faster printing speed, and no smearing. How- ever laser printers are more expensive than inkjet printers, which many people use because they are lower in cost yet still produce high quality images and remain relatively fast in operation. Besides these two types, the advantages of impact printers are their low printing cost per page, their ability to print on multi-part forms and their reliability. However these printers are much louder as well as slower than inkjet and laser printers.[46]
Personal printers and network printers are distinguish- able by their connection to either a single computer or a home/office network. Network printers allow multiple computers to print from the same printer, which is why they are a standard in the business setting. Typically per- sonal printers have a rate of 20 to 35 ppm (pages per minute) whereas network printers can print from 30 to 65 ppm. Printers can connect via USB, wired or wireless networks, or connections from other devices such as memory cards or cameras. It is not uncommon to see printers that have multiple capabilities like copying, scanning and faxing. These inkjet or laser printers are known as multifunction devices and they can come in color or black-and-white options.
2.24.1 Laser printers
Why choose laser printer over any other printer? Well, Laser Printers are known to be good for their speed, pre- cision and economy. Since it uses a laser, it can print one page at a time so it’s known to be significantly faster than the ink-jet printers. Although they are more expensive than ink-jet, they seem to be more cost-efficient consid- ering ink is more expensive than toner powder, which is used for laser printers. Laser printers are more reliable with their prints because ink-jet printers tend to leave ink smears. Static electricity is the primary principle in mak-
Laser Printer
ing the printer work, which is an electrical charge built up on an insulated object. It uses objects with opposite static electricity forcing the fields to cling together. Laser printers can work in either black-and-white or in color. To print on a page, a piece of paper must be first be inserted into the loading tray of the printer. A laser beam electrically charges the drum in the necessary lo- cations that the microprocessor in the computer has de- coded based on the image being printed. The ink used is a fine powdered ink known as toner, which is applied while the paper rolls over the drum. The paper finally goes through a fusing unit which permanently binds the toner to the paper. [47] [48]
Ink-jet Printers
Ink jet printers: Why choose Ink-jet printers? Well, ink- jet printers create pictures by spraying ink from the ink cartridges onto the page. Depending on the printer there’s different sized ink droplets, nozzles and electrical charges for more precise printing. They are typically slower than laser printers because of the back and forth motion of the ink tray. Ink-jet printers have grown in popularity and performance while dropping significantly in price. These dots are thinner than a strand of hair and when different colors combined together to create photo-quality images. [49]
Special-Purpose Printers: Though almost every house-
2.24. PRINTERS 63
3D Printer
hold has some sort of either ink jet printer or laser printer, there are also numerous special purpose printers out there that are made to perform a specific task. Many compa- nies invest in these products to improve time and cost efficiency. Some examples of these printers are photo printers, bar code, label and postage printers, portable and integrated printers, and 3D printers. -Photo print- ers, as the name quite obviously gives it away, are used for the purpose of printing merely pictures. Often times, people invest in these printers because they produce a better quality picture than just a typical everyday printer would. They also have certain capabilities and apps that one would not just find on any printer. -Businesses are also often found using bar code, label, and postage print- ers for their products. Every sellable item needs a prod- uct label, and having a printer that is designed just for that saves both time and money. They are also useful for the electronic postage capabilities, saving companies time on the mass amount of envelops that they send out on a daily basis. -If you are an on the go businessman or woman, a portable or integrated printer is the way to go. With so much travel and back and forth, it is easy to pull out these commutable printers and print the documents or images you need on the fly. -Finally, possibly the newest and most up and coming printer is the 3D printer. This useful tool can be utilized for printing models and samples. It prints using plastic, and literally produces a finalized 3D prototype of what you want. With technology rapidly im-
proving, more and more products are being designed for the purpose of cost and time efficiency. Depending on what you do on an every day basis, it may be a very wise choice to invest in one of these printers to save you valu- able time and money in the long run. [50] −3D Printers
A 3D printed Beethoven.
3D printers use virtual designs created in advanced pro- grams such as CAD (Computer Aided Design) or scanned using a 3D scanner to print out physical models and parts. In order to do this, the software must “slice” the model into thousands of layers that the printer lays down one at at time. There are various kinds of manufacturing meth- ods, such as FDM where material is melted into layers or SLS printing where powdered material is sintered into layers.[51] 3D printing has many applications, especially in design. Even manufacturers now use the printers to create rapid prototypes for research. This saves compa- nies both money and time since changes only need to be made the design file on the computer.[52]
There are different 3d printing methods that were devel- oped to build 3D structures and objects. Some of them are very popular nowadays, others have been dominated by competitors. Most of popular types of 3d printers are: - Fused deposition modeling (FDM) - 3D printing ma- chines that use FDM Technology build objects layer by layer from the very bottom up by heating and extruding thermoplastic filament. - Stereolithography (SLA) - SLA 3D printers work with excess of liquid plastic that after some time hardens and forms into solid object. - Selective Laser Sintering (SLS) - Selective Laser Sinter- ing (SLS) is a technique that uses laser as power source to form solid 3D objects. The main difference between SLS and SLA is that it uses powdered material in the vat instead of liquid resin as stereolithography does. - Selective laser melting (SLM) - Selective laser melting (SLM) is a technique that also uses 3D CAD data as a source and forms 3D object by means of a high-power laser beam that fuses and melts metallic powders together. - Electronic Beam Melting (EBM) - The same as SLM,
64 CHAPTER 2. HARDWARE
this 3d printing method is a powder bed fusion tech- nique. While SLM uses high-power laser beam as its power source, EBM uses an electron beam instead, which is the main difference between these two methods. The rest of the processes is pretty similar. - Laminated Object Manufacturing (LOM) - During the LOM process, layers of adhesive-coated paper, plastic or metal laminates are fused together using heat and pressure and then cut to shape with a computer controlled laser or knife. [53]
2.25 Review
-Glossary barcode A machine-readable code that represents data as a set of bars. computer speakers Output devices connected to com- puters that provide audio output. CRT monitor A type of display device that projects im- ages onto a display screen using a technology similar to the one used with conventional TVs. data projector A display device that projects all com- puter output to a wall or projection screen. graphics tablet A flat, rectangular input device that is used in conjunction with a stylus to transfer drawings, sketches, and anything written on the device to a com- puter. handwriting recognition The ability of a device to iden- tify handwritten characters. headphones A personal audio output device used by an individual so only he or she can hear the sound ink-jet printer An output device that sprays droplets of ink to produce images on paper. keyboard An input device containing numerous keys that can be used to input letters, numbers, and other symbols. laser printer An output device that uses toner powder and technology similar to that of a photocopier to produce images on paper. liquid crystal display (LCD) A type of flat-panel display that uses charged liquid crystals to display images. monitor A display device for a desktop computer. mouse A common pointing device that the user slides along a flat surface to move a pointer around the screen and clicks its buttons to make selections. multifunction device (MFD) A device that offers mul- tiple functions (such as printing, scanning, and faxing) in a single unit. optical character recognition (OCR) The ability of a computer to recognize scanned text characters and con- vert them to electronic form as text, not images.
organic light emitting diode (OLED) display A type of flat-panel display that uses emissive organic material to display brighter and sharper images. See organic light emitting diode (OLED) display photo printer An output device designed for printing digital photographs. pixel The smallest colorable area in an electronic image, such as a scanned image, a digital photograph, or an im- age displayed on a display screen. pointing device An input device that moves an on-screen pointer, such as an arrow, to allow the user to select ob- jects on the screen. printer An output device that produces output on paper. radio frequency identification (RFID) A technology used to store and transmit data located in RFID tags. scanner An input device that reads printed text and graphics and transfers them to a computer in digital form. speech recognition system A system, consisting of ap- propriate hardware and software, used to recognize voice input, such as dictation or audio computer commands. stylus An input device that is used to write electronically on the display screen. touch pad A small rectangular-shaped input device, of- ten found on notebook and netbook computers, that is touched with the finger or thumb to control an on-screen pointer and make selections. touch screen A display device that is touched with the finger to issue commands or otherwise provide input to the connected device.
2.26 Review Questions
The vocabulary may or may not be listed above. What am i? 1. The smallest area of an image in which makes up a whole image. 2. Two of the most familiar_____are UPC and ISBN. 3. A device that is designed to convert physical form to data. 4. With a typical ____________ the sounds are broken into digit representation of Phonemes. 5. An output device that uses toner powder and technol- ogy similar to that of a photocopier to produce images on paper. 6. The device that shares the information on a screen. 7. The ability of a device to identify handwritten charac- ters. 8. A personal audio output device heard by an individual. 9. A display device that projects all computer output to a
2.28. REFERENCES 65
wall or projection screen. 10. An input device that moves an on-screen pointer, such as an arrow, to allow the user to select objects on the screen.
2.27 Answers
1. Pixel 2. Barcodes 3. Scanner 4. Speech Recogni- tion System 5. Laser Printer 6. Moniter 7. Handwriting Recognition 8. Headphones 9. Data Projector 10. Point- ing Device
2.28 References [1] http://en.wikipedia.org/wiki/QWERTY
[2] http://www.pcworld.com/article/242037/mechanical_ keyboard_faq_pick_the_right_switch.html
[3] http://www.buzzle.com/articles/ different-types-of-keyboards.html
[4] http://www.buzzle.com/articles/ different-types-of-keyboards.html
[5] http://www.buzzle.com/articles/ different-types-of-keyboards.html
[6] http://www.buzzle.com/articles/ different-types-of-keyboards.html
[7] http://www.computer-hardware-explained.com/ history-of-computer-keyboards.html
[8] http://www.gizmag.com/ galaxy-note-3-vs-iphone-6-plus/33905/
[9] https://en.wikipedia.org/wiki/Touchscreen
[10] http://www.nytimes.com/2012/ 08/02/technology/personaltech/ on-touch-screens-rest-your-finger-by-using-a-stylus-state-of-the-art. html?pagewanted=all&_r=0
[11] https://en.wikipedia.org/wiki/Pointing_device
[12] http://whatis.techtarget.com/definition/scanner
[13] http://computer.howstuffworks.com/scanner.htm
[14] http://electronics.howstuffworks.com/ how-to-understand-film-scan-resolution.htm
[15] http://whatis.techtarget.com/definition/ barcode-reader-POS-scanner-bar-code-reader-price-scanner
[16] https://en.wikipedia.org/wiki/QR_code
[17] http://www.freeqrcodes.org/
[18] http://electronics.howstuffworks.com/gadgets/ high-tech-gadgets/rfid.htm
[19] https://www.google.com/search?q=digital+cameras& oq=digital+cameras&aqs=chrome..69i57j0l3.2852j0& sourceid=chrome&ie=UTF-8#q=information+on+ cameras
[20] Understanding Computers: Today and Tomorrow Com- prehensive 14th ed. by Morley & Parker
[21] Understanding Computers: Today and Tomorrow Com- prehensive 14th ed. by Morley & Parker
[22] http://en.wikipedia.org/wiki/Video_camera
[23] Understanding Computers: Today and Tomorrow Com- prehensive 14th ed. by Morley & Parker
[24] http://en.wikipedia.org/wiki/Video_camera
[25] http://www.fbi.gov/about-us/cjis/fingerprints_ biometrics
[26] http://www.biometricsinstitute.org/pages/faq-3.html
[27] http://electronics.howstuffworks.com/gadgets/ high-tech-gadgets/speech-recognition.htm
[28] http://www.webopedia.com/TERM/V/voice_ recognition.html
[29] https://en.wikipedia.org/wiki/Speech_recognition
[30] http://publications.rafa-elayyan.ca/27.pdf
[31] http://en.wikipedia.org/wiki/ITunes
[32] https://www.youtube.com/
[33] https://signup.netflix.com/
[34] http://en.wikipedia.org/wiki/Subwoofer
[35] http://www.amazon.com/ Barnes-Noble-eBook-Reader-Black/dp/1400532620
[36] http://www.displaymate.com/crtvslcd.html
[37] http://www.necdisplay.com/Documents/WhitePapers/ Measuring_Screen_Size.pdf
[38] http://www.northcanton.sparcc.org/~{}technology/ Tutorials/Files/Using_a_Data_Projector.pdf
[39] http://popsci.typepad.com/popsci/2007/09/ dont-publish-a-.html
[40] http://www.accessscience.com/content.aspx?id=757559
[41] http://www.supercircuits.com/resources/learn/ top-7-benefits-of-an-led-monitor
[42] https://www.qualcomm.com/media/documents/files/ mirasol-imod-tech-overview.pdf
[43] http://www.bestbuy.com/site/electronics-promotions/ hdmi-cables/pcmcat210800050015.c?id= pcmcat210800050015
[44] http://www.nextgeninteractions.com/ virtual-and-augmented-reality/
[45] http://en.wikipedia.org/wiki/Dots_per_inch
66 CHAPTER 2. HARDWARE
[46] http://wiki.pcworld.com/index.php/Different_Types_ of_printers_-_pc_world_tutorial
[47] http://computer.howstuffworks.com/laser-printer.htm
[48] http://computer.howstuffworks.com/laser-printer12.htm
[49] http://computer.howstuffworks.com/inkjet-printer.htm
[50] http://printscan.about.com/od/printerscannerreviews/u/ Reviews.htm
[51] http://www.3dprinter.net/reference/what-is-3d-printing
[52] http://3dprinting.com/what-is-3d-printing/
[53] http://3dprintingfromscratch.com/common/ types-of-3d-printers-or-3d-printing-technologies-overview/
Chapter 3
Software
3.1 System Software
3.2 Systems Software Overview
Ubuntu 12.04 is an example of a OS
System software can be separated into two different cate- gories, utility programs and operating systems. Operating systems are the foundation of your computer and almost every electronic device. The OS boots up the computer and makes sure everything is operational. The OS is also what runs your cell phone and most of your electronic de- vices. The OS is, for the most part, the GUI that shows you all of your applications, and without the OS you can- not use the computer. There are many different types of OS’s which are discussed later. Utility programs per- form a very specific task, to either enhance or manage your computer. For example your virus protection pro- gram, like norton[1], is an example of a utility program along with the install/uninstall program that comes stan- dard with Windows.
3.2.1 Systems Software vs Application Software
Systems Software
Systems Software are applications or programs that are designed specifically for running the hardware on a per- sonal computer and are used to maintain a platform for Application Software to be used. This means that sys- tems software is designed to communicate with the in-
ternal parts of your computer such as the hard drive, RAM, ROM, cache, microprocessors, etc. so that the user doesn't have to. It contains all of the drivers nec- essary for this type of communication, and ,in the most simplest sense, it is the interface between the user and the hardware.[2] The Operating System (called the OS for short) on your computer is not only one of the most important systems software on a computer, but is also the most frequently used. It is the software that runs in the background and brings the separate, physical parts of the computer together in order to provide the seamless stream of activity that a user experiences. Some of its responsibilities include the transfer of data between the memory and disks (on your hard drive) as well as provid- ing the information needed to display icons, text, cursors and other visible necessities on the display screen. This display is called the graphical user interface or GUI and is entirely the result of the OS on the computer. This can be compared by viewing the differences between the Ubuntu OS and the Mac Snow Leopard OS. The icons between the two are positioned differently and they look different too. The Mac OS and GUI tends to have a more three dimensional aspect to it where Windows tends to appear more flat. It should also be remembered that the operat- ing system conducts itself independently of both the user and any application software being used. This means that it is not directly dependent on the user or other programs in order to operate. Some other systems software would include Bios and device firmware. These help the user interact with other utilities such as diagnostic tools, lan- guage translators, data communication programs, as well as data management programs. [3]
• Ubuntu GUI
• Mac GUI
Application Software
Application Software are the most common programs that run in the foreground of the computer. They tend to perform useful tasks which are not associated with com- puter maintenance, system boot-up, or hardware commu- nication. Application software is directly reliant on the Systems Software to communicate to the physical com-
67
68 CHAPTER 3. SOFTWARE
ponents of the computer and cannot operate without it. If you were to visualize this, the Application Software would operate on top of the Systems Software and would be the most visible to the user while the Systems Software would remain in the background unnoticed. The Systems Software would then communicate to the Hardware on its behalf and deliver any information to it from the Appli- cation Software. In turn, any information needed from the Hardware would pass through the Systems Software to the Application Software. Application Software are the most familiar forms of software and come in a vari- ety of types. Most often they can be accessed through the graphical user interface of the operating system be- ing used by double-clicking on an icon. Some of the most popular examples include word processors, spread- sheets, photo-editing programs, database programs, and accounting programs to name a few. This list is by no means the extent to which application software may be used and many more programs are being created con- stantly to help individuals with daily activities. [4]
•
3.3 The Operating System
A computer would not be able to function correctly with- out an operating system. An operating system is a soft- ware program that empowers the computer hardware to communicate and operate with the computer software.[5] An operating system is one of the most important parts of a computer. The operating system is able to do basic tasks as well as complex tasks. An operating system can be classified as a multiuser, multiprocessing, multitask- ing, multithreading, and real time. The operating system makes sure that different programs, and users running at the same time, do not interfere with one another. The owner of a computer interacts with the operating system through a set of commands. All application programs need an operating system. Also, operating systems op- timizes one’s computer performance. Most of the work that is involved in the operating system is unnoticed be- cause it does the work behind the scenes. This system is in charge of managing one’s network connections. Consid- ering all the new technology out, operating systems must be uploaded in order to support the new technology being uploaded to computers. All in all, the operating system is the core of all computers.
• Operating system architecture
3.3.1 Multitasking and Multithreading
Multitasking is a computer’s ability to seemingly run multiple tasks or processes at the same time. For ex- ample, you might have an Internet browser open to read this page while also having a word processor open to take
A screenshot from a computer that is running multiple applica- tions, which is possible due to the processor’s multitasking capa- bilities.
notes and a media player open to stream music. In real- ity, however, the computer is not actually able to process multiple tasks simultaneously; rather, it switches between them at incredibly quick speeds to give the appearance of working on them simultaneously. CPUs have become faster over time, which allows computers to increasingly run more applications at the same time and switch be- tween them more quickly and seamlessly. If computers could not do this, a user would have to painstakingly close an application any time he or she wanted to do anything in another application.
With Continuity, Apple devices become more connected
Continuity is a new form of multitasking. Continuity was a new feature that came together with Apple’s iOS 8 and OS X Yosemite. It lets you seamlessly move between
3.4. OPERATING SYSTEMS FOR PERSONAL COMPUTERS 69
your compatible Apple devices or use them all simulta- neously. Continuity includes features such as Handoff, Phone Calling, Instant Hotspot, and SMS. Handoff is a feature wherein you can start work from one device then continue on another. For example, you may be work- ing on a document on your Mac but then suddenly you have to leave the desktop. With Handoff, you can simply continue your work on the iPad while you are away from the desktop. Phone Calling is simply phone calls on your computer or tablet when they are connected to your phone through the same Wi-Fi network. This allows for instant responses to calls without having the need to use your phone. Instant Hotspot is where your iPhone can pro- vide internet access to your other devices. Finally, SMS allows you to send and receive text messages to and from your computer or tablet. This allows for you to seamlessly answer messages without even lifting your phone. Conti- nuity is basically taking the concept of multitasking and simplifying it by using multiple devices instead of using multiple CPUS.[6]
Multithreading, on the other hand, is a computer’s abil- ity to perform multiple operations within a given task at seemingly the same time. Again, the processor is not ac- tually able to do multiple things simultaneously, but it is able to switch between different actions so quickly that, for all intents and purposes as far as the user is concerned, it is doing them simultaneously.[7]
3.3.2 Functions of the Operating System
Some of the primary functions of the operating system in- clude creating an interface for the user and the computer to interact, booting up the computer, configuring devices, managing network connections, and managing the jobs of the computer.
User Interface
Graphical User Interface
In order for computers and users to interact, some sort of user interface must be provided. User interfaces can be based on text, such as the original DOS that was used in the 1980s and 1990s, or it can be based on graphics. Most personal computers and mobile devices today use a graphical user interface, also known as GUI, which uses visuals such as icons, desktops, pointers, and menus for users to utilize. Basic forms of graphical user interface include the use of checkboxes, lists, and other fundamen- tal forms of input. Examples of graphical user interfaces include Windows, Mac OS, and many other modern op- erating systems.
Booting the Computer
BIOS chip
Another function of the operating system involves boot- ing up the computer. This process occurs when the CPU (if it’s in a multi-core processor, one is designated) which contains the bootstrap processor (BSP) initiates the ba- sic input/output system (BIOS) which contains a set of instructions that tell the computer how to boot up. The BIOS chip tells the computer to look for the boot loader. The boot loader’s job is to initiate the operating system. It does this by finding the kernel, which contains the operat- ing system, and loading it into the memory. [8] The BIOS also performs a power-on self-test (POST). The POST ensures that all the functions and components of the com- puter are properly working before startup.
3.4 Operating Systems for Per- sonal Computers
3.4.1 Buffering and Spooling
The part of the operating system used mostly with print- ers is buffering. This part can be in the RAM (Random Access Memory) or the hard drive. This area is meant to hold the input and the output during their way out of the system. [9] Although many people are familiar with buffering having to do with loading while streaming
70 CHAPTER 3. SOFTWARE
Printed spool half
videos and music, it can also be referred to as a tempo- rary form of memory. [10] While a buffer is doing its job, the CPU can change data before relocating to any other devices. When items are placed into a buffer waiting to be regained, this is called spooling. Along with buffers being used with printers, spooling often refers to print spooling. Many college campuses have print spooling, which enables one printer to have multiple print jobs sent to it at one time. These multiple documents can be sent all from the same computer or more than one. While this spooling occurs, there is a print queue that all documents waiting can be stored until they are printed. Spooling is a very useful tool because while one device may not run as fast, it provides documents with a waiting area in the meantime.
DOS
DOS (Disk Operating System) was the dominant operat- ing system for microcomputers in the 1980s and the early 1990s. The first version of DOS was developed for IBM. DOS is a rather simple operating system but it does not utilize a graphical user interface and it does not support modern processors, which is why it is no longer used. [11] Some computers can still run the DOS commands but the user needs to know how to input the commands using the Command Prompt window. This non-graphical operating system was originally writ- ten by Tim Paterson and was introduced in August 1981. The last DOS system to be released was the MS-DOS 6.22 in 1994. The DOS system used a command line, instead of a GUI (graphical user interface), to allow the user to navigate, open files, and perform other functions. [12] Today, people use a mouse to navigate the computer and carry out commands, but with the DOS there was a command-line interface which had specific commands put in a prompt, which then brought up whatever file or program was prompted. Later, software programs with menu-based or icon-based interfaces were created for convenience. While the DOS systems are not used any- more, the command shell, now called the Windows com- mand line, is still used today. [13]
• Part of a DOS code page
• A Command Line Interface Page
Windows
Windows is a series of operating systems that is designed by Microsoft. The first two versions of the Windows op- erating system, introduced in 1985 and 1987 respectively, were primitive. Windows 1.0 had only basic functions such as MS Paint and a word processor and Windows 2.0 had very rudimentary versions of Word and Excel. Windows did not become popular until its third release in 1990. Windows 3.0 had enhanced graphics, the abil- ity to “multi-task”, and (for the first time) virtual mem- ory. This version was so popular that it stayed on the market for eleven years. The next big improvement came with Windows 95, which expanded from 16-bit to 32- bit. Windows 2000 was known for its increase in plug-in devices that were congruent with the operating system. Windows XP, or Windows 2001, included a comprehen- sive help center to allow users to utilize different types of media and was designed mostly for user ease and con- venience. [14] The main feature of Windows Vista is the Instant Search at the bottom of the start menu. Then Win- dows 7 came out and the improvements were mainly to make it faster and easier to use. The most recent version of Windows is Windows 10. Windows 10 came out late July 2015. The new Windows will allow you do to more than one thing at once. It also allows for a new way to search and there is a way to open the Windows store from your home page.[15] Windows is the most commonly used operating system and is used on about 90% of all personal computers.
• Screenshot of Microsoft Windows 1.0
• A Presentation of Windows 8
Mac OS
Apple Corporation’s registered operating system is called Mac OS. There are many different branches stemming from the Mac OS X family. It was primarily based off of UNIX because of its standard interface and graphics look. Mac OS X Snow Leopard was the primary operat- ing system, followed by the making of Mac OS X Moun- tain Lion, which is the newest and greatest version of Mac Operating Systems. Mac OS has capabilities of multi- threading and multitasking. It also has a 64-bit proces- sor that runs with applications used with 64-bit software. The many great features of Mac OS X creates an easy working environment for students, teachers, and parents to easily access many files. Mac OS is also known for its great graphic features that are popular to artsy users. The Launchpad and Mission Control with the bird’s-eye view of the Dashboard and desktop make opening applications easier for users. Apple plans to launch a new operating system in the Fall of 2014 titled OS X Yosemite, which
3.4. OPERATING SYSTEMS FOR PERSONAL COMPUTERS 71
will feature a redesigned interface as well as multiple ways for users to perform activities across their Apple devices. [16]
UNIX
Shell Servidor X
Unix Kernel
Outras Aplicações
Unix-kernel
UNIX was trademarked in 1969 by a group of AT&T employees at Bell Labs as a multitasking, and multi-user computer operating system. UNIX can support systems ranging from microcomputers to mainframes, along with various devices. Because UNIX is used for an assort- ment of categories of computers, this is a great advantage. However, it is more expensive than most operating sys- tems, and is very difficult to maintain upgrades. UNIX is widely known for its simplicity and ease while work- ing on the computer, therefore different companies use a spin off of UNIX as their operating system, like Mac OS X. UNIX has just celebrated their 40th anniversary of being a business Unix combines the worldwide single Unix specification with X/open company’s XPG4, IEEE’s POSIX standards and ISO C. Single UNIX Specification defines this product in four parts specification, product, trademark, and technology allowing it to still be success- ful even though it was separated from AT&T and found its own angle. It allowed for one open consensus spec- ification that is the requirement for the UNIX systems. UNIX was one of the first operating systems to be written in a high-level programming language and could possibly be installed on any computer. This high-level program- ming language was also developed by Dennis Ritchie at the Bell Labs, which allows a more flexible language to be used in various applications thus being very beneficial for businesses. It being inexpensive allowed for many people to be a big fan of UNIX and actually many universities use it for that reason. It never really took off in the home computer business but for workstations it tends to be the number one choice. The source language was open so if
anyone got a hold of it they could change it to fit their own needs the best.
• Unix OS
Linux
Tux-linux logo
Linux is an open- source, portable, multi-user (multi- ple users can access system resources like memory/ ram/ application programs at same time), multiprogramming, operating system that was first released by Linus Torvalds in October 1991. It is very similar to other operating sys- tems, such as Windows and OS X [17]and a source is avail- able to the public, to which users can download Linux via the Internet and have the capability to run another op- erating system on their PC or Mac. No other company has done this before. The system has primary three com- ponents: Kernel (the core part of Linux), system library (special functions or programs), and system utility (re- sponsible to do specialized, individual level tasks).Linux is one of the leading operating system on servers, main- frame computers and supercomputers. > Linux is used on a lot of popular electronic devices, such as mobile phones, tablet computers, network routers, facility au- tomation controls, televisions and video game consoles. The system is widely used by local and national govern- ments. The US Navy’s newest warship that is armed with missiles and robot guns is powered by Linux,[18] Spain is using Linux in education, and China uses Linux to achieve technology independence. Collaborators of Linux are continually making improvements to the sys- tem.
72 CHAPTER 3. SOFTWARE
Chrome OS
Google Chrome OS
Chrome OS is an open-source operating system created by Google to create a better computing experience for people who spend most of their time on the web. [19]On June 15, 2011, Chrome OS was launched to the public with the first Chromebooks, notebooks using the Chrome OS, created by Samsung and Acer. Today, Chromebooks are created by a number of other computer companies including HP, Toshiba, Asus, and Dell. The main reason that Chrome OS is different from other operating systems is that it allows for user data and applications to reside in the cloud, taking up less space on the computer hard- ware. Because of this, many Chromebooks only contain the same amount of memory and RAM as the average smartphone, Google, however, supplies each user with one-hundred gigabytes of Google Drive cloud storage for up to two years. There are many things one should consider when purchas- ing a computer. One of the biggest factors one should be aware of is what operating system the computer uses. Different operating systems have different features to suit the user’s needs. If one is looking into a smaller laptop computer, they might consider a Google Chromebook, which uses Chrome OS. It is a good idea to look into the pros and cons of a computer’s operating system before making a purchase. Like all operating systems, Chrome OS has both advantages and disadvantages. One positive feature is that Chrome OS is based on Linux, which is virtually virus free, which means users will be safer from threats. Another great feature is its ability for fast boot times, generally loading in just under ten seconds. It also allows for different users to configure it differently ac- cording to their needs, and saves each person’s data sepa- rately, creating privacy for each user. One of the cons of this operating system is that it does not allow installation of new apps. Users must use web-based apps instead,
Acer AC700-1099 Chromebook 2013-12-22 00-39
which they can get in the Chrome Web store. Another feature that the Chromebook is lacking is a user friendly printing option. In order to print something, one must have a Cloud Print Ready Printer. It lacks the conve- nience to simply plug it in to an existing printer and print, which could become an annoyance. Another feature that may seem inconvenient is that Chromebooks require in- ternet access to do most of its work. Users that have tasks such as editing video or making movies may find that a Chromebook is not for them. It seems there are advan- tages and disadvantages for Chrome OS, and one should take them into consideration when deciding which oper- ating system will suit their needs best.
3.5 Operating Systems for Mobile Phones
There are many different operating systems for mobile phones and devices but most six stand out as being most used. These are Android, Asha, Blackberry, iOS, Win- dows Phone, and Windows RT.
Android
Android is a free and open source operating system pro- vided by Google. Since the release of Android 2.0, the operating system can be used on phones and tablets. Since HTC Dream was introduced, making the number of mobile devices capable of carrying the Android oper- ating system heighten, Android’s worldwide market rose significantly and now reaches 52.5% of the global smarth- phone market share.
3.5. OPERATING SYSTEMS FOR MOBILE PHONES 73
Assorted smartphones.
Asha
Asha is used by Nokia phones. These smartphones are on the lower end when it comes to software and component capability. Because of the low capability, Nokia smart- phones are usually the cheapest which makes them able to compete with higher end smartphones.
Blackberry
Blackberry’s operating system is called BlackBerry 10. This is a closed source operating system for smartphone and tablet devices. The newest operating system de- veloped by Blackberry for tablet devices is BlackBerry Tablet OS. The BlackBerry operating system has all of the same features a smart phone does: email access, web browsing, phone calls, play music and video, and send and receive text messages. Most models are not touch screen, with the exception of the Storm and the Torch. Instead of a touch screen, a trackball or track pad is the hardware used for navigation. Because there is no touch screen, the operating system does not require that much battery life to process so the phone stays on longer than others. [20] The BlackBerry also has multiple buttons (similar to the image on the right) including a BlackBerry button, back button, call and end button, 1 or 2 convenience keys, and a full keyboard. The BlackBerry button is designed for easy integration, such as sharing a photo via email. This sys- tem is geared toward communications rather than games and apps. It features an email software that “pushes” email directly to the user’s phone, which saves battery and provides the most current information. One drawback to this type of smart phone is how limited the customization is. Only the wallpaper and the function of a few buttons can be changed. It also does not feature “widgets” or a wide selection of apps like the android phones do. Over- all this operating system is easy for productivity, but falls behind its competitors in a wide selection of applications.
Star C6000
iOS
iOS is Apple’s operating system for Apple’s iPhone, iPod Touch, iPad and second-generation Apple TVs. This op- erating system is closed source and not until iOS 2.0 were third party applications offically supported. Prior to this update, jailbreaking was the only way to allow third party applications access to a user’s iOS device. As of Septem- ber 2015, iOS is in its 9th iteration. It was introduced at Apple’s product convention in the fall of 2015 in con- junction with the new iPad. iOS is known for a colorful graphics, and an easy to understand user interface. This being said, it was created as an OS for mobile devices, and thus was designed primarily for consuming content as opposed to creating content. As Apple’s new iPad is designed for both consuming and creating content, iOS needed to be upgraded accordingly. The latest version includes the ability to split screen multi task on to appli- cations at the same time, similar to a laptop. In addition, it includes new built application as well as upgrades to exist- ing applications. Apple Maps now includes public trans- portation, and more apps can integrate with the cloud. Siri, a “personal assistant” has also been upgraded to do more tasks, and to integrate with additional apps, such as Pictures. Finally, there are new multi touch gestures built in to the system. These assist the user in typing, editing
74 CHAPTER 3. SOFTWARE
projects, taking notes, emailing and other tasks typically associated with a laptop computer. Generally, iOS 9 is built to create content rather than simply consuming. [21]
IOS 9 Logo
Windows Phone
Windows Phone is developed by Microsoft as a closed source operating system for mobile phones. It allows users to accesss Microsoft SkyDrive, Office, Xbox, and other Microsoft programs remotely. Windows Phone de- vices are made mostly by Nokia, HTC, Samsung, and Huawei. On April 14, 2014, Microsoft released its newest mobile operating system, Phone 8.1. The new operating system contained new features including Cor- tana, a personal assistant similar to Apple’s Siri. The OS also featured upgrades in security, performance, and boot time.
Windows RT
Windows RT is also developed by Microsoft but this is used on tablet devices. This version closely resembles Windows 8, an operating system developed by Microsoft for computers. It is closed source as well.
Symbian OS
There was one OS that used to tower above all the rest, before recently falling completely out of the race thanks to increasingly competitive and more simplistic operating systems. The name of this OS is Symbian, and between 2000-10 it ruled supreme thanks to its partnership with Nokia, a company that excelled in moving large units of inexpensive cellphones. The Symbian company had risen from the ashes of a failing PDA company named Psion,
This was the logo for the now declining empire known as Symbian OS.
changing its focus to mobile OS development with fund- ing from entities such as Motorola and Ericsson, while the largest funding share always came from Nokia. Un- fortunately, between the more complex code (which con- tributed to development periods that were unthinkable in comparison to what Windows and Mac were developing) and Nokia changing their allegiance to Windows, Sym- bian said its final goodbye in mid-2013. Any individuals or companies still attached to the Symbian OS will be of- fered support for a few more years, but they will need to consider their options now instead of waiting for the last minute. Luckily, as can be seen from the plethora of op- tions above, Symbian users can surely pick an OS that is the closest to the quality programming to which they had grown attached.[22]
Mobile Device Systems
Below are three very popular mobile phone/device providers today. They are Windows, Android, and Ap- ple. The three use different operating systems. Windows is full of change. Most people have used Win- dows on their personal computers, but did you know it is also integrated into our GPS systems, ATMs, and even robots? Windows mobile devices include things called tiles which are icons for different things stored in the de- vice itself. Related tiles can be put together in hubs. Win- dows devices also offer integration with windows office software (Word, Excel, PowerPoint, etc.). They also in- clude integration with Xbox Live. [23]
Android: Android was created by a group of 30+ mobile technology companies and is based on the Linux operat- ing system. These devices offer the ability to multitask with a split thing (doing two things on the same screen verses switching between tasks). The screen will contain multiple applications that can be bought and downloaded (some for free) from the Android Market.[24]
iOS (Apple): This system is based on Apple’s Mac OS X. Similar to the apps of the android system, apple prod-
3.6. UTILITY PROGRAMS 75
ucts also contain apps but they are downloaded and pur- chased from the App Store. There are over 900,000 apps currently available. These devices are also synced to your iTunes account allowing you to upload your music to their devices as well. Some things that are specific to these devices are their Safari web browser, FaceTime, and the ability to track your device through the “Find my iPhone” app. [25]
3.6 Utility Programs
1328102004 Defragmentation
In general, the utility program is defined as special soft- ware written to take care of the operating system main- tenance and management to keep the performance of a computer system at the appropriate level. The utility pro- grams could be a part of operating system or a product of third party developers. Whether you want to install pro- grams or move file to a different folder, search for a doc- ument or set the connection to the network, you are using the utility program tools. Another important improve- ment the utilities can help you with is your hard drive performance. Disc check, disc clean up and disc defrag- mentation programs alone with a files compression utility will let you keep your storage organized and reduce the time of the searching, retrieving and displaying informa- tion you requested. The last but not least task the utility programs are being applied for is the operating system and your data protection. The backup and recovery pro- grams let us be sure that we will not lose all data in case of system malfunctions and will be able to return back to re- store point, when the system was working properly, while the antivirus, antispyware and firewalls – utility programs – will protect the computer from data theft.
Folders
File Management Program
They organize files and are available for the user to access them. There are 6 important concepts that the file man- agement programs have. To start off, it has a navigation system that gives the user access to the file hierarchy and be able to find their work. The actions to proceed are us- ing the “up” and “down” to navigate through the folders and “go to” to reach their data. Another function is the operations functions which allow the user to interact with the files. The common functions along with this are as fol- lows: open, save, close, copy, move, delete, rename, new and share. The user would obviously be concern about the security of their files. With this being said, the files can be blocked with a login procedure which will only give people that know the username and password access to the file. To keep your file program organized its nec- essary to maintain the storage on the program in which you should delete any unneeded files. For the conveyance to the user, there is a communications function in which there are links available in order to send out a file to a given location. Lastly, there’s a search function in which you can find a particular file you are looking for.
Search box
Specifically the Search Tool is very useful for the user. Like explain previously, it will find a particular file by simply using the files name. there are programs that will search the data by key words but it seems to be more beneficial to know the username instead of the program searching all the documents for key words, which may lead to a longer search than intended. [26] Also, a file can be searched based on other reasons, including if it is kept in a certain folder, if it has certain characters in its file name, if it has metadata tags, or if it is a specific type of file. If you do not know, a metadata tag includes informa- tion about the file, like its author, artist, or keyword. The
76 CHAPTER 3. SOFTWARE
program being used can set this automatically or it can be manually set to fit your needs. Also, the types of files that can be searched are documents, spreadsheets, videos, or songs. These search tools can be integrated into the op- erating systems that your computer is designed to run, or you can download them off the Internet for free or at a low charge. Some Internet based search tools, called desktop search tools, can find certain Web pages, messages sent over the Internet, or certain e-mails. A few of the web- sites that provide these services are Google, Yahoo!, and Bing. Other search tools that you can download off the In- ternet serve specific purposes, like finding duplicate files on your hard drive. This can come in handy when your computer’s hard drive storage is running high. In con- clusion, the search tool utility program provides you with great accessibility to your files and documents when you don’t have time to spare. [27]
Diagnostic and Disc Management Programs
With technology playing such an important role in our everyday life, it is important to make sure that is it main- taining itself and running properly. Instead of having to go through and check every aspect of the computer our- selves, computers come with built in diagnostic manage- ment program and disc management programs. Diagnos- tic management programs deal with making sure that ev- erything on the system is working the way it should be, while disc management systems programs worry about the hard drive operating correctly. Most computers come with the basics of this software already built in, however some people prefer to go outside of what they already have and purchase more protection and security for their computer. These programs keep your computer running quickly, optimally, and effectively on a daily basis.[28]
Deleting Unneeded Files
Uninstall and Cleanup Utilities
You would think that that once a program or application is deleted, no trace of it would be left behind; however, this is very often not the case. In many instances, traces of that file, program, or application are still left embed- ded into your hard drive. In order to fully get rid of them, people often use something called uninstall utili- ties. These programs go through your hard drive and re- move any unneeded space, memory, or left over remnants from that application that once existed. Many comput- ers come with this option already installed, which makes keeping your computer updated and up to speed an easy task. Clean up utilities are very similar to uninstall util- ities; however, instead of going through and deleting old applications and programs, they go through and clean up your computer by deleting temporary files.[29]
The floppy drive that holds one of the original computer worms released into the Internet
File Compression Programs
File compression programs are designed to reduce the size of files, which allows the user more storage space. For Windows users, these compressed files usually have the .zip or .zipx file extension. The most popular pro- grams are Winrar, Winzip and 7-Zip.[30] For Mac users, these files usually have the .sit or .sitx format. Programs that are commonly used are RAR Expander, StuffIt Ex- pander and MacZip. Some programs have the option of encrypting the zipped files, meaning that a password is required to open the file. This can help those who want
3.7. REVIEW 77
to protect their files for themselves or specific users who are granted access. Overall using file compression pro- grams is an efficient way to free up storage space for other computer tasks. The gzip program is a popular file com- pression program that compresses and decompresses files using Lempel-Ziv coding (LZ77). [31]
Backup and Recovery Utilities
Over time one might experience the unfortunate event of a power outage or some other event that leads to the cor- ruption of important system files. For example a storm can cut the power in an instant, which turns off the com- puter in an unsafe manner thereby leading to the corrup- tion of the operating system and possibly even hardware. The system now is damaged, and this is an important rea- son why backing up is necessary. Businesses understand this, so it is extremely unlikely for a one to not backup its data on a regular basis because the possibility of los- ing just a segment can be catastrophic. The Windows Backup program (Windows) and Time Machine program (Mac) are included with their respective operating sys- tems, but software programs exist that can be used for free or a price.
Antivirus, Antispyware, Firewalls, and Other Secu- rity Programs
Malware consists of viruses, trojans, worms, spyware and other forms that disrupt computer operation. As mentioned, malware can infect computers in many ways, whereas the affected suffers while the infector gains. To protect against these threats, it is highly recommended to take advantage of the utility programs offered by the operating system as well as software programs. Popu- lar antivirus programs for Windows include AVG, Norton 360, McAfee, Kaspersky and Microsoft Security Essen- tials. A firewall is used to monitor network ports by con- trolling inbound and outbound traffic to the network.[32] Its primary purpose is to defend the computer from mal- ware and hackers, but it can also interfere with programs that must access the Internet. It will also not remove malware if it has infected the computer; it only blocks the malware from entering.[33] Spyware is software that tracks personal information unknowningly from the user, which can lead to serious problems.[34] It is important to know the software one is downloading and to understand its license agreement and privacy statement (to see if un- wanted software is included).
3.7 Review
3.7.1 Review: Key Terms
Android: A Linux-based operating system designed for mobile phones and developed by the Open Handset Al- liance, which is a group of companies led by Google. application software: Programs that enable users to per- form specific tasks on a computer, such as writing a letter or playing a game. BlackBerry OS: The operating system designed for BlackBerry devices. command line interface: A user interface that requires the user to communicate instructions to the computer via typed commands. buffer: An area in RAM or on the hard drive designated to hold input and output on their way in and out of the system. device driver: A program that enables an operating sys- tem to communicate with a specific hardware device; of- ten referred to simply as a driver. file compression program: A program that reduces the size of files, typically to be stored or transmitted more efficiently. graphical user interface (GUI): A graphically based in- terface that allows a user to communicate instructions to the computer easily. kernel: The essential portion, or core, of an operating system. Linux: An open source operating system that is available without charge over the Internet and is increasingly being used with mobile devices, personal computers, servers, mainframes, and supercomputers. mobile operating system: A type of operating system used with mobile phones and other mobile devices. server operating system: A type of operating system designed to be installed on a network server. Symbian OS: An operating system historically used with mobile phones, primarily outside North America. system software: Programs, such as the operating sys- tem, that control the operation of a computer and its de- vices, as well as enable application software to run on the computer. utility program: A type of software that performs a spe- cific task, usually related to managing or maintaining a computer system. virtual memory: A memory-management technique that uses hard drive space as additional RAM. Windows: The primary personal computer operating system developed by Microsoft Corporation; the most re- cent version is Windows 7, with Windows 8 expected to be released in 2012. Windows Embedded: A family of operating systems
78 CHAPTER 3. SOFTWARE
based on Windows that is designed for nonpersonal com- puter devices, such as cash registers and consumer elec- tronic devices. Windows Phone: The version of Windows designed for mobile phones; the current version is Windows Phone 7. Windows Server: The version of Windows designed for server use; the current version is Windows Server 2008 R2.
3.7.2 Review Questions
1. A computer’s __________ is a collection of programs that manage and coordinate the activities taking place within the computer and it is the most critical piece of software installed on the computer. 2. _______ refers to the ability of an operating system to have more than one program open at one time. 3. A _______ is an area in RAM or on the hard drive designed to hold input and output on their way in or out of the system. 4. The process of placing items in a buffer so they can be retrieved by the appropriate device when needed is called _______. 5. The older DOS operating system and some ver- sions of the UNIX and Linux operating systems use a __________, although versions of UNIX and Linux are available. 6. Operating systems used with personal computers are typically referred to as __________ and they are designed to be installed on a single computer. 7. There have been many different versions of ________ over the years; the next few sections chronicle the main developments of this operating system. 8._________ is an operating system developed by Linus Torvalds in 1992 when he was a student at the University of Helsinki in Finland. 9. The mobile operating system designed for Apple mo- bile phone and mobile devices, such as the iPhone and the iPod Touch, is _______. 10. Creating a _________ means making a duplicate copy of important files so that when a problem occurs, you can restore those files using the backup copy to avoid data loss.
3.7.3 Answer Key for Review Questions
1.operating system 2.multitasking 3.buffer 4.spooling 5.command line interface 6.personal operating systems 7.windows 8.linux 9.iOS 10.backup
3.7.4 Review Reference
http://coursemate.cengage.com/ CPReader/View/9781133114598/ default.aspx?eISBN=9781133114598# 98bca867-5ebb-4d73-9876-8f6d676ce984
3.8 References [1] http://us.norton.com/
[2] http://ecomputernotes.com/ fundamental/disk-operating-system/ difference-between-application-software-and-system-software
[3] http://www.buzzle.com/articles/ application-software-vs-system-software.html
[4] http://uwf.edu/clemley/cgs1570w/notes/concepts-3.htm
[5] http://www.computerhope.com/os.htm
[6] https://support.apple.com/en-us/HT204681
[7] http://www.ni.com/white-paper/6424/en/
[8] http://www.tldp.org/HOWTO/ Unix-and-Internet-Fundamentals-HOWTO/bootup. html
[9] Understanding Computer Today and Tomorrow 14th Edi- tion Comprehensive
[10] http://www.computerhope.com/jargon/b/buffer.htm
[11] http://searchsecurity.techtarget.com/definition/DOS
[12] http://www.computerhope.com/jargon/m/msdos.htm
[13] http://www.computerhope.com/jargon/m/msdos.htm
[14] http://windows-operating-system-reviews. toptenreviews.com/a-brief-history-of-the-windows-operating-system. html
[15] http://windows.microsoft.com/en-us/windows-8/ everywhere?ocid=Everywhere_O_WOL_Hero_Home_ WinEverywhere_Pos1_01
[16] https://www.apple.com/osx/preview/
[17] https://www.linux.com/learn/new-user-guides/ 376-linux-is-everywhere-an-overview-of-the-linux-operating-system
[18] http://arstechnica.com/information-technology/2013/ 10/the-navys-newest-warship-is-powered-by-linux/
[19] http://www.chromium.org/chromium-os
[20] http://www.techradar.com/us/news/ phone-and-communications/mobile-phones/ android-v-blackberry-smartphones-for-business-1136674
[21] http://www.apple.com/ios/whats-new/
[22] http://www.pcworld.com/article/2042071/ the-end-of-symbian-nokia-ships-last-handset-with-the-mobile-os. html
3.10. APPLICATION SOFTWARE BASICS 79
[23] http://www.windowsphone.com/en-us/features? ocid=sem_s_pcrid_30043429957_se_Google_kwd_ windows%20mobile%207%20games_pmt_b
[24] http://www.android.com/about/
[25] http://www.apple.com/iphone/
[26] http://smallbusiness.chron.com/ functions-file-management-program-41476.html
[27] http://www.techrepublic.com/blog/five-apps/ five-fast-windows-desktop-search-utilities/
[28] http://www.krollontrack.com/information-management/ hard-drive-management/
[29] http://support.microsoft.com/kb/2438651
[30] http://download.cnet.com/windows/file-compression/ ?tag=rb_content;main
[31] “Man Page for gzip (freebsd Section 0)". 2001- 05-24. http://www.unix.com/man-page/freebsd/0/gzip/. Retrieved 2015-02-21.
[32] http://www.cat-5-cable-company.com/ faq-what-is-a-Firewall.html
[33] http://www.ehow.com/about_7547911_ purpose-firewall-software.html
[34] http://www.microsoft.com/security/pc-security/ spyware-whatis.aspx
3.9 Application Software
3.10 Application Software Basics
Google Drive Logo
Application software allows you to do anything on the computer, such as playing games, or watching TV. Any- one and everyone using a computer should be familiar with the different applications available to them and how
Commercial Software-Microsoft Office
to properly utilize said programs. For instance one of the most widely used application software is Microsoft Word.[1] Microsoft Word allows you to create, edit, save and print digital documents on your computer. While it is not the only word processor out there, it is the most popular. Others would include WordPerfect,[2] Google drive,[3] and iWork.[4] You could also create spread- sheets through Excel,[5] create a presentation through Keynote,[6] and even edit music though Audacity.[7] All of these will be discussed in greater detail as we move on in this section.
3.10.1 Installed vs. Web-based
Dropbox is a web-based software
There are two different types of application software: in- stalled software and web-based software. Installed soft- ware must first be installed to the computer before it can be used. When you purchase an installed software, the company can either send you a physical copy of the soft- ware, usually in the form of a CD, or you might also have the option of downloading the software from the compa-
80 CHAPTER 3. SOFTWARE
nies webpage. Web-based software is software that re- mains on the internet which you can use at an on-demand basis. Web-based software is also referred to as Software as a Service or Cloudware. Some web-based softwares in- clude Google Docs, Dropbox, Prezi, and many others.[8]
Advantages and Disadvantages
Web-based software has recently become a more pop- ular alternative to installed software, however, it has its advantages and disadvantages. One of the advantages of web-based software is that as long as you have an Inter- net connection, you can access your files. This allows for you to access the same files from many different de- vice including desktops, laptops, tablets, and mobile de- vices. Also, this allows for users to be working on one shared file rather than continuously sending edited files back and forth to each other. With web-based software, only one file exists, so it avoids confusion and even al- lows for multiple users to be working on one file at the same time. Also, instead of having to continuously in- stall software updates, web-based software stays updated online by whatever company owns the software.[9] Some of the disadvantages of software include file size limits. The amount of files as well as the size of each file are de- pendent upon how much cloud storage the application’s company allows on its servers. Many companies such as Google, Apple, and Dropbox, charge monthly or annual fees if users want more storage space. With installed soft- ware, the amount of storage you have is only dependent on how much storage space you have on your computer. If you know that you’re going to use a lot of storage space, it would be better to have an installed software so that you can avoid paying large fees for taking up server space. Another disadvantage to web-based software is slower speeds. Because the applications are being used through the Internet, it takes more time to access the files. Also, users have to deal with logins and security precautions such as creating passwords, linking emails to an account, and answering questions if you forget your password.[10]
3.10.2 Creating Application Software
Thanks to the revolution that is the smartphone, appli- cations have become incredibly popular that there are countless of them out there and the number is still grow- ing. There can potentially be an application for every- thing. However in order for there to be an application for everything, they have to be created first and in order to do so one must learn to code. Depending on the type of application you want to create, you must learn differ- ent types of programming languages. The more compli- cated your applications, from mobile apps to full-on video games, the more complicated the coding. Most mobile applications can be created by one person but more com- plicated programs such as video games are usually created by a team of programmers.
You must learn to code in order to make applicaions
The two most popular software marketplaces as of right now are that of Apple’s App Store and Google’s Play Store. In order to create apps for the App Store, one must have a Mac computer to run the programming tools. One must then pay Apple to sign us as a developer in order to download those tools. The programming language used in those apps is called Objective-C. To create apps for the Play Store, one must have either a Windows, Mac, or Linux computer. The software development kit is free to download and you will need to know the programming language called Java.[11]
3.10.3 Software Ownership
After an application software program is developed, the author has what is called ownership rights. These rights specify exactly how the program can and cannot be used. For example, ownership rights allow the author to decide on whether or not the program can be sold, shared, or distributed. The ownership rights vary depending on the type of software. Types of software include commer- cial, shareware, freeware, and public domain.[12] Com- mercial software is software that is created and then sold for profit. For example, Microsoft Office Suite is com- mercial software. Shareware is another type of software that can make profit, however, shareware is initially free and then requests payment after a certain amount of time. For example, a computer game might have a ten day free trial, but after the trial is over the developer will ask for a payment. This payment would allow the gamer to play the computer game on a regular basis. Freeware is a type of software that is available for no charge by the developer. An example of freeware would be Internet Explorer and most other web browsers. Public domain software is sim- ilar to freeware, but should not be confused. While free- ware is copyrighted, public domain software isn’t. Be- cause public domain software isn’t copyrighted, people are able to copy, modify, and distribute the software.[13]
3.12. WORD PROCESSING 81
The logo for Adobe Creative Suite v6.0, one example of a soft- ware suite.
3.11 Software Suites
A software suite is a group of related programs that in- teract together and are purchased together. The most well-known example is Microsoft Office, which includes Excel (spreadsheets), Word (documents), PowerPoint (slideshow), and Outlook (email). There are two pri- mary benefits of software suites. First, they make it easier for the user to work on multiple related projects at once: someone can, for example, make a spreadsheet in Excel and then bring it into Word, keeping all of the format- ting intact much more easily than if they used an unre- lated spreadsheet program and text editing program. Sec- ond, they save money: purchasing the entire Office suite is much cheaper than purchasing Excel, Word, Power- Point, and Outlook separately. However, a user may not need all of the programs in a given suite, so buying the en- tire suite when only one or two programs are needed is a significant waste of money; a prospective suite consumer should look in detail at which programs are included and make sure they need all of them. If not all of the programs are needed, then it would be more prudent to purchase in- dividually only those programs which are needed.[14]
3.12 Word Processing
Explanation of Word Processing
A word processor is a software program that is used to create a document, store it electronically, display it on a screen, modify it using commands and characters, and print it on a printer. It also processes paragraph inden- tation, margin size, font type, font size, font color, and spacing within the document being created. Word pro-
cessors have replaced typewriters since they allow the user to make a change anywhere in the document without having to retype the entire page. Word processors also come equipped with “spell-check” functions eliminating the need for multiple editors and provide an immediate tool for grammatical correction. Some common word processors include Microsoft Word, AbiWord, Word Per- fect, and Open Office.[15]
• Spell Check
Constructing a Word Processing Script
When constructing a word document there are a few things to keep in mind; character formatting, paragraph formatting, and page formatting. These three basic func- tions lay the foundation for most of the customization that is needed to create many word documents. Character for- matting changes the appearance of individual characters and relates to the size, font, color, and overall style of the letters or numbers being used. Character formatting also involves underlining, italicizing, and making bold those characters being used. This is great for making a word stand out or for underlining book titles. Paragraph for- matting adjusts the spacing, alignment, and indentation of the paragraphs being formed. Spacing refers to the amount of lines left blank in between the lines being pro- cessed. A good example of this is double-spacing which is commonly used in an educational setting where a stu- dent has to write a paper for a specific instructor. Com- monly double-spacing is used so that the instructor can make corrections to the document without having to mark over the actual words on the paper. Alignment refers to the way the paragraph is positioned in regards to the left and right margins. A left alignment is most com- monly used when creating a word document and this set- ting aligns the words being formed to be flush with the left margin. A center alignment is usually used for ti- tling a paper. Page formatting refers to the width of the margins, the size of the paper being used, and the orien- tation of the page. The standard margin is 1.25 inches on both the left and right but these can be customized to suit need and preference. The paper size options reflect what can be used in the printer, and the orientation in- dicates whether the document will use the traditional or landscape positioning on that paper. Traditional orien- tation is 8.5 inches wide by 11 inches tall whereas land- scape is the exact opposite at 11 inches wide by 8.5 inches tall.[16]
• AbiWord Word Processor
Word Processing Tools
• Business ID Template
Some of the basic tools that are employed in word pro- cessing programs that help to make the application more
82 CHAPTER 3. SOFTWARE
user friendly are tables, graphics, and templates. These tools allow for minimal effort and excellent results when adding features like these to a word document. Tables are used for organizing information and are composed of rows and columns in which data is placed. This is great for comparing and contrasting information as it’s condensed and presented in a straight forward fashion. Tables can also be used for laying out entire documents, such as a resume, where information is sectioned off from one another. In this example, the entire report is for- mulated to a table instead of a small section as men- tioned earlier. Graphics are pictures, drawings, clip art, or other images that can be inserted into a document from other programs or from stored data on a computer. This makes for easy illustrations where a picture, or pictures, would suffice better than words or tables to highlight a point. Graphics tools also allow the user to manipulate the images that have been imported by changing the color, contrast, brightness, and size of the image, among other things. The customization process of these images in a word processor provide for an easy and quick avenue of explanation concerning the topics at hand. Another use- ful tool are Templates. These are preprogrammed ar- rangements of ideas and/or illustrations that are known to serve a purpose and are already organized for the user to interact with. Most often this means “filling in the blanks” and some common templates that should be rec- ognized are resumes, business cards, identification cards, fax cover sheets, memos, invoices, and newsletters to name a few.[17]
Microsoft Word 2013 Icon
Along with templates, some documents are required to look differently depending on the use; as a result of this we change the format of our documents. Any change in format in a document is a change in the overall ap- pearance. Examples of formatting documents can range from MLA to APA format, requiring different sized mar- gins, fonts, etc. In order to do this, Word has tabs that
make navigating around your document easy and effi- cient. Word includes a Help Center convenient for users to receive assistance whether it is live online help or of- fline. In this Help Center, tools such as where and how contents are organized are listed in a user-friendly man- ner. While Word processing is simply creating, editing, saving, and printing, the creation and edition are made easy by Word for a variety of end results in the overall appearance of documents. In the time of typewriters, the “carriage return” was used when a line of text needed to move to the next line to continue. With present day Word, this is done automatically and is a process called Word Wrapping.[18] Other tools that Word offers which were not available are the ability to contain various fonts, edit proportions, and spacing is also made more efficient.
3.13 Spreadsheets
3.13.1 What is a Spreadsheet
Poppit Spreadsheet
} “A spreadsheet is a group of values and other data or- ganized into rows and columns similar to the ruled pa- per worksheets traditionally used by bookkeepers and ac- countants.” The spreadsheet software is mandatory to cre- ate computerized spreadsheets. Microsoft Excel is a form of a spreadsheet. There are many terms one must have to know to create a spreadsheet. A worksheet is the sin- gle spreadsheet document. A workbook allows multiple worksheets to be saved together in a single spreadsheet file. Worksheets are divided into rows and columns. The intersection of a row is called a cell. One must enter content into the active cell, or current cell; it has a bor- der around it to make it be easily identified. Data is en- tered directly into worksheet cells by clicking a cell to
3.13. SPREADSHEETS 83
make it the active cell. Labels, constant values, formu- las, and functions are the data that is entered into a cell. Before one enters a formula or function into a cell, one must begin with some type of mathematical symbol, usu- ally the equal sign (=).[19] Spreadsheets are greatly used in businesses. They are used to organize finances, projects, statistics, etc.[20] It is essential to know how to use spread- sheets for school and one’s job.
3.13.2 Tables, Graphics, and Templates
Table-Microsoft Excel
Tables, graphics, and templates are all available to a user with application software, such as Microsoft Word, Mi- crosoft Excel, and PowerPoint. Tables are ways a user can organize data and information at their convenience. According to Microsoft Word, there are now many differ- ent available options for users who are looking for various kinds of tables. These different options include the fol- lowing: the Graphic Grid, Insert Table, Draw Table, in- sert a new or existing Excel Spreadsheet table, and Quick Tables. The concept of using tables for data input is rel- atively simple. In order for a user to insert a table, the user must first open Microsoft Word. Once they have done this, they must click the “table” button to customize the table to achieve their needs. The overall format for a table consists of a large (or small) grid that can be al- tered by the amount of information the user has, ex. four columns five rows. Next, the user must insert the table into the word document by selecting “insert table” from the dropdown menu. [21] Graphics in Microsoft Word are pictures, or clip art that are able to be inserted into a Microsoft Word document, Excel Spreadsheet, Pow- erPoint slide, or any other Office application. Graphics are inserted into these Office Applications to enhance the information presented in a Word Document, Excel worksheet, or PowerPoint slide. A user can insert their own picture through their office documents; add clip art, shapes, SmartArt, screenshot, or Word Art.[22] Templates are pre-constructed document layouts whose primary use is to assist a user in creating a specific type of document in a convenient amount of time. The different options of templates vary, but a few of the following are common ones used every day: agendas, brochures, calendars, fly- ers, fax covers, and many more. Templates are used to save a user time, and confusion in creating their docu- ment. [23]
3.13.3 How to use a Spreadsheet
When using a spreadsheet application, the user can use various concepts to compute the data entered into the cells in the spreadhseet. These different concepts are pro- vided within the program. Some very common concepts that are utilized are charts, functions, formulas, and cell referencing.
Charts
A chart can be created as its own object or embedded within the sheet itself.[24] This is helpful when a user needs to analyze data or represent changing data.
• A chart generated using Excel.
Functions
A function is a pre-programmed mathematical formula to allow the user to make calcuations based on the data input. The functions under spreadsheets are there to per- form a simple calculation by using a certain value, called arguments. If the user wishes to create his own formula, Visual Basic can be used to write a formula and then the spreadsheet program can input the values into the newly written formula, reporting the data back into the sheet.There are many different reasons to have functions on spreadsheets. One would be for arithmetic functions to process numerical data. The next would be statisti- cal functions that use analysis tools and averaging tools. This would be useful for finding the average of the num- bers in a certain row/column on a spreadsheet. The next function is date that processes and converts dates. This function could be used to put the sequential dates in or- der on the spreadsheet. The next function is logic func- tions that process logic data. An example of logic data would be an AND/OR function. If there was something that needed to be marked yes if it is above 5 and marked no if it is below 5 then that would be a logic function. The last one is financial functions that process monetary data. They all must start with an equal sign, the name of the function, parenthesis opening and closing. In the function a comma or semicolon is used as the delimiter, depending on what settings are there in the spreadsheet would depend on which one to use. An example would be =SUM(A1:A4), this function would find the sum in those cells. Some of the most common functions are SUM, AV- ERAGE, IF, COUNT, MAX and MIN.
• A function being editted using VB in Excel.
Formulas
A formula identifies the calculation needed to place the result in the cell it is contained within. This means a cell
84 CHAPTER 3. SOFTWARE
has two display components; the formula itself and the resulting value.[25] Typically, a formula consists of five expressions: value, references, arithmetic operations, re- lation operations, and functions. By using these expres- sions, formulas can help to make tables, solve math prob- lems, calculate a mortgage, figure out accounting tasks, and many other business-related tasks that use to be done tediously on paper.[26]
A formula always starts with an equals sign (=), followed by a constant, a function or a reference, then followed by an operator, and then followed by another constant, func- tion or reference. A constant is a value that never changes; this includes numbers, dates, titles and other text input. References represent a certain cell, such as “A2”. An op- erator is usually a math symbol, such as “+” or “*” which tells the computer how to compute (add or multiply, re- spectively) the given constants or functions given in the formula. It is good to be careful that one knows the differ- ence between a constant and a reference. If the constant “30” is input into cell A3, and the formula says “=30+2”, then if A3’s value changes, the expression of the formula will not change unless the formula itself changes. If one wishes to have a formula that returns the value of a cell, then the formula should read “=A3+2”. Another thing to note is that the operators will follow the basic “rules” of calculation. For example, the formula “=3+2*4” will add 3 to product of 2 and 4, rather than add 3 and 2, then mul- tiply the sum times 4. (Parenthesis can be used to change the order: (3+2)*4 would add first, then multiply.) Oper- ators are not always arithmetic, they can also be compar- ison, text concatenation, and reference operators. Com- parison includes greater than, lesser than, greater than or equal to, and lesser than or equal to. To connect two val- ues into one value, a text concatenation (the “and” sign i.e. “&”) is used. The signs used as reference operators are the following: a colon is used to reference two cells and all the cells between them (i.e. B1:B10); a comma is used to combine multiple references into one reference (i.e. B1:B10,C1:C10); and a space is used as an intersec- tion operator.[27]
• Using a formula in Excel.
• Spreadsheet Graphics
Cell Referencing
Cell referencing refers to the ability to call on other cells. There are two ways of doing this: relative and absolute cell referencing. A relative cell reference will adjust as the formula is copied from another cell white an absolute will not adjust. It is also important to note that a user can reference both the same sheet and other sheets in a book using this concept.
Pivot Tables
One the most powerful features available in the Microsoft Office spreadsheet program Excel, is pivot tables. Pivot tables allow you to manipulate large amounts of raw data.[28] It makes it easy to analyze the data in different ways, with a simple click and drag. Vast quantities of data can be summarized in a variety of ways. Calculations can be performed by row or column. Data can be filtered or sorted automatically by any or all of the fields. Excel can even recommend a basic layout of a pivot table based on the type of data selected. A wizard is available to assist in the creation of the table. An important thing to remem- ber when using pivot tables, is that any time the original data source is modified, the data must be refreshed in the pivot.
Sample Pivot Table
Once the pivot table has been created and the data has been analyzed in a meaningful way, it can then be repre- sented graphically using pivot charts. All the basic chart types available in Excel are available in the pivot chart menu. Much like the pivot tables they are built on, they can also be manipulated with ease. They can be filtered to display only the relevant information form the main data source.
3.14 Database
<gallery> A database is an organized collection of facts and infor- mation such as text and numbers, and often can hold still images, sounds and videos or film clips.[29] It is organizing data in such a way that a computer program can quickly select desired pieces of information. A database can also be referred to as an electronic filing system. For exam- ple, libraries, rather than have a file cabinet, provide ac- cess to academic databases for use in scholarly projects. Regular PC databases are organized by fields, records, tables, and files. A field (column) is a single piece of information like last name, address, phone number, and such. A record (row) is a one complete set of fields. A table is a collection of records. Lastly, a file is a collec- tion of related tables.[30] A database file is created first, then tables that can be created in either datasheet or de- sign view.[31] There are different kinds of databases, such as active, cloud, deductive, distributed, graph, hypertext,
3.14. DATABASE 85
etc. For example, in hypertext database, any object can be linked to another object; this is useful for organiz- ing a lot of information. A DBMS is database manage- ment software that allows the definition, creation, query- ing, update, and administration of databases.[32] Com- mon database management software is Microsoft Access. Since many databases store confidential and important in- formation, they require passwords and other security fea- tures in order to access the information.[33]
Queries and Reports
Query
Queries and reports are used to retrieve information from databases.[34] A query is almost like a search tool for the user of the database to find specific information like an item, number, name, etc. Like other documents made, a query has to be made and saved as well, for users to be able to come back and search it again. A query con- tains criteria that must be met for a record or row to be shown in the ending results of the specific query. Queries can also be made to show multiple columns or rows at a single time, instead of just one row or column. For ex- ample, a customer insists to buy a set of glasses for under $20 at Crate and Barrel.[35] The employee can then in- quire “glasses under $20” and be able to tell the customer which kind to specifically look at. A report is used when acquiring a formal output. This can be a company logo or graphic with a page column heading. These can be cre- ated with the “Report Wizard button” on the “Create tab” from the Ribbon. Reports are mostly used with database tables or queries. Databases can be used more efficiently for customers shopping via the Internet. Today, online shopping is the newest sensation. For example, a spe- cific dress can be found on Lord and Taylor’s [36] website for women, prior to going to the store by typing in the search bar. Examples of popular databases used are Mi- crosoft SQL Server, Microsoft Access, Oracle, MySQL,
and IBM DB2.[37]
Microsoft Access 2013 logo
Deciding Which Database to Use
How does one know which kind of database to use? To someone not familiar with this kind of thing, it could be a situation where one does not even know where to begin. Something one must first consider is what they will be us- ing the database for. Database Managing Systems can be broken up into two categories; server databases or desk- top databases. Desktop databases are typically geared to- ward a single user, whereas server databases must accom- modate multi-users and large amounts of data. Some fa- miliar types of Desktop DB are Microsoft Access, Fox Pro, File Manager, or Paradox. Desktop DB’s are fit for storing less complex data and are less expensive then server DB’s, typically around one hundred dollars. They are also very user friendly and have web functionality that allows the user to publish data on the web. Server databases on the other hand are equipped to store and manage much larger amounts of data and allow for many users to have access to that data at the same time. Some popular Server DB’s are Microsoft SQL, Oracle or IBM DB2. Due to their complex functionality, these data bases are much more expensive, ranging in the thousands and up. Server DB’s are equipped with Application Program- mer Interfaces (API’s) that allow for custom program- ming and applications. They are extremely powerful, be- ing able to accommodate cluster servers and multiple high speed processors. They are also able to adapt well to the constant addition of users and data. After evaluat- ing these two types of databases, one should have a better idea of which one will best suit their needs.[38]
86 CHAPTER 3. SOFTWARE
DB2 Client Connections
Database protection
The database is one of the most essential parts of a busi- ness process. The ability to access and to operate data is a necessary condition for the running company. Permanent data loss puts the business in serious danger. According to some researchers, about a half of the companies af- fected by disasters and major loss of corporate data, have not been able to continue their activities. There are few most common reasons for database destruction: equip- ment failures, physical impact on the hardware of the database, errors of authorized users, database or operat- ing system bugs and errors in application programs, inten- tional acts unauthorized users or programs. The primary protection tools such the user’s identification, the granting of different rights of access to database objects e.g. read- ing, adding, deleting, and changing along with data and programs encryption can provide the acceptable security level. Note, that the security model, based on the basic mechanisms of authorization and authentication does not solve problems such as stolen user IDs and passwords or malicious actions of some users with the authority. [39]
3.15 Presentation Graphics
Intro to Presentation Software
Everyone has different styles of learning. There are some students who retain information better when they can be hands-on, while others can hear a lecture from their teacher one time and remember all the important points without having to open their school book once. No matter your learning style, there is one type of software that has been proven, time and again, to be a great method of shar- ing lots of key information in an organized and relatively entertaining fashion. The successful software in question is presentation software.[40] Presentation software allows the user to create multiple slides which they can piece to- gether into a slide-show. It is a great way to organize and refine large amounts of information into only the most important parts because each slide has limited space and you typically are limited in time when responsible for a
Just because the phrasing is corny doesn't make the message any less true!
U.S. Navy uses presentation graphics to educate
presentation. Whether you're presenting information to a classroom or a business meeting, the method of organiz- ing information in a fluid manner remains the same. To add entertainment value, there are many variables within each example of software that can be manipulated, from text size and color to slide transitions. The expert pre- sentation software users can even dare to add photos and music to their presentations. Two of the most widely used examples of presentation software today are: Microsoft Powerpoint and Prezi. Presentation graphics is a type of software that allows users to create stylized audio and visual aids (sound ef- fects, animation, etc.) typically for slideshows, reports, and public informational speeches. It incorporates tools for inserting various types of drawings, text and back- ground schemes in a wide variety of fonts, colors, and patterns. Most systems can also import specific data from a spreadsheet application to generate customized charts and graphs. Presentation programs can be divided into two categories -- business graphics software and general multimedia authoring tools. Though some products are blended, the layout of business presentation software em- phasizes fast learning and ease of use, while multime- dia software offers a more sophisticated presentation that will likely require a higher level of technological under- standing. Popular presentation software, such as Mi-
3.15. PRESENTATION GRAPHICS 87
A chart of the 2002 Iranian Economy using Apple Keynote
crosoft’s Powerpoint or Apple’s Keynote, may be pur- chased independently or as part of an office suite. Uni- versally compatible products include Adobe Persuasion, Corel Presentations, Harvard Graphics, and Lotus Free- lance Graphics. Free products include Google Slides, Prezi, PowToon, and Academic Presenter. All function similarly and provide nearly identical capabilities. Upon completion, the file(s) are usually saved to a computer, external storage device, or the cloud. During a presen- tation, users are able to view miniature images of slides on a device’s screen, and edit or direct their layout as they are simultaneously projected onto a larger screen or LCD projection panel for others to view. [41]
3.15.1 Powerpoint
US Navy 040605-N-6633C-002 Commander Naval Reserve Force, Vice Adm. John G. Cotton, is silhouetted in front of a Powerpoint slide mapping out the Naval Reserve Force’s future
Powerpoint is a Microsoft Office software used to present information and work as a visual aide. Certain options make it easy to organize and present information in a visually appealing way. Charts, pictures, tables, video
clips, and sounds can all be added to the presentation. Designs and color themes come ready to use so the pre- senter just has to add the information and it is ready to go! The slides themselves come with several options of pre-loaded layouts, using features such as bullet points, pictures, captions, and titles. They are easy to drag and drop to make rearranging very easy.[42] The whole idea of a digital visual is, in concept, more beneficial to the presenters and the audience to avoid copies of handouts. One feature that comes in handy, however, is the ability to print the slides so either the presenter or audience can be informed ahead of time of what to expect. Slides can change with a simple click of a button. However, pre- senters can often lose eye contact from the audience and begin reading straight from the slides, instead of using it as a guide. Teachers, employers, and computer users all over the world have now become accustomed to using PowerPoint as their “go-to” visual aide. The image on the right shows a presenter using a powerpoint as a visual aide.
A PowerPoint Presentation slideshow is projected on a large screen for the audience.
The PowerPoint presentation graphics program provides the user with several assortment tools and operations for creating and editing slides. With those tools, one is able to add new or delete old slides that are previewed in the slide thumbnail tab area, usually found on the left side of the screen. One is also able to switch to the slide out- line tab, which contains only the title and the main text included in the slide. If desired, using the Insert tab, the user can perform additional operations like exporting im- ages, along with adding formatted tables, shapes, sym- bols, charts, and much more to better express their mes- sage. Additionally, to customize the PowerPoint to make it even more dynamic and presentable, text can be ani- mated, and a unique transition can be added to the slides. With animation, text can be set to appear in a specific way in the slide during a slide show. Tons of special effects are provided for the user, including animations to make the text to fly, dissolve, fly, float, or bounce in. Simi- larly, one is also able to apply special effects to specific slides to transition from one slide to another in a spe-
88 CHAPTER 3. SOFTWARE
cific manner. Additionally, Microsoft PowerPoint allows recorded narration to be played back as the slideshow is being presented, along with speaker notes. Furthermore, most presentation graphics programs also allow the user to print those speaker notes for the targeted audience’s convenience. [43]
3.15.2 Inside Scoop on New Presentation Software
Sample Prezi
There are hundreds of ways we present information on a daily basis. Whether it be through verbal speech, body language, pamphlets, posters, commercials, flyers, power points, etc. we are constantly presenting information and being presented to. Technologically, there are still many ways to present information to an audience. The cool thing is, you do not just have to use things like Power- Point and Microsoft Word. You do not even have to use products that cost money. There are several new and in- novative free ways to present that will surely grab the at- tention of your audience. Prezi is one of those free presentation methods. It is In- ternet based, and similar to PowerPoint. However, it is much more user friendly, as well as interactive. Power- Point seems to have a set order you have to follow. It goes slide to slide in a single order. With Prezi, if you decide you want to go in a different order or go back to something 6 slides back you simply zoom out a little and click the slide you wanted to return to. Prezi slides are set in a “path” and as you present, the presentation will zoom in and out of each slide which are all present on one master screen. This is much different from Power- Point’s single slide screens. Prezi has the ability to inte- grate many different forms of information into your pre- sentation. You can upload YouTube videos, PDFs, Excel spreadsheets, photos, music, and voice overs. You can also time your slides and have them move to the next one automatically like in PowerPoint. However, these things are input through a much simpler process. Instead of all the clicks you have to do in PowerPoint to insert things such as a YouTube video, Prezi has a button labeled “In- sert YouTube video” and once you click it, it asks for the video URL. After you enter that, it automatically uploads
it to your presentation. There you can resize it and place it wherever you would like. The ability to see where one idea came from and how it is physically moving to the next idea makes Prezi a much more innovative presen- tation method. It can be used for entertainment, educa- tional work, teaching, and even in the business world. It comes with many templates as well at the ability to create your own presentation from scratch. Prezi also offers many interesting things PowerPoint does not: it has the ability to share the presentation via email, collaborate on a presentation with multiple people, give several people access to the editing of a single presenta- tion, and a free mobile app. The app is free and allows you to present, create, and edit presentations on the go with or without Internet. It is a very useful program and definitely something to check out! [44]
3.16 Graphics and Multimedia
Paintshop
Graphic Software
CorelDRAW Graphics Suite X6 Logo
Graphic software has a variety of application programs and has a wide range of different uses. To further ex- plain, there are programs like presentation programs that can create power points and graphics software uses photo editing programs that are used to manipulate pixels from images from pictures. A useful program would be Adobe Paint Shop, which can be used to edit, change and al- ter pictures however you would like them to be. Another category for creating images would be vector based im- ages. This is where a bit-mapped image created by a dig- ital camera is able to be altered and the images are able to
3.16. GRAPHICS AND MULTIMEDIA 89
re-scale to any size with no loss of detail. Also, each ob- ject in a given picture can be layered over another. This allows someone to take out one specific object if they do not like how it overlaps or covers another object in the picture. Graphs, tables, diagrams, charts, or images usu- ally present the information on a drawing program. This makes drawing programs most appealing to small busi- nesses trying to advertise their product to a wider vari- ety by creating business cards, stylish logos, and more. Also, marketing professionals use drawing programs to create intriguing Web pages, corporate images, and other business related necessities. Also, drawing programs are used by architects, shipbuilders, aerospace engineers, home-designers, prosthetic engineers, landscapers, and construction managers because of the scale-to-size and fixed-point accuracy of the program. Other common fea- tures of a drawing software program are batch conver- sion, text-to-speech conversion, auto-indexing, layout re- tention, and the ability to print. Newer programs that are being created come with unique features like TWAIN, which can be used by a Macintosh to allow image hard- ware devices to communicate with image processing soft- ware. Popular drawing program software in use today is computer-aided design (CAD), computer-aided man- ufacturing (CAM), Adobe Illustrator, CorelDRAW, MS Paint, and GNU image manipulation program (GIMP). All of these types of software can be used by the public or by businesses.[45] As well as the programs, the graph- ics side of them is able to create images in 3-D modeling, as well as create animations which can be made through Photoshop.
PROTIP: Headphones are useful when listening to sound.
In able to add video or audio there is programs with mul- timedia content which the software is able to play and editing audio and video along with any editing. Over- all, graphic software is really useful for personal, busi- ness and education purposes, whether it’s for creating a college or providing information with addition affect for the audience.[46]
Audio Capture and Editing Software
Audio capture and audio editing software is used to cre- ate and edit audio files. There are many different pro- grams associated with these two types of programs. Some programs are designed to extract audio from CDs (rip- ping software) while others capture sound through input devices like a microphone (sound recording software). Some programs are able to record sound and also edit that sound, or it can open a certain type of sound file, which enables the user to edit any piece in various ways. The ex- tent to which the user can edit the sound depends on the complexity of the software. One program can only allow very basic functions like cutting and pasting while another can add effects and modify every bit of the wavelength. This is an example of the distinction found between free programs and others deemed professional. However that is not to say that just because a program is free it must be of a lower quality. Audacity is a free, and very popular, program that includes both audio capturing and editing elements.[47]
One professional audio editing program that does cost money is Pro Tools, created by Avid Technology.[48] This software works similar to a multi-track recorded and mixer, but has a wide array of digital features. One such feature that is commonly used in the software is MIDI, which stands for Musical Instrument Digital Interface.[49] A MIDI device can link up to sixteen channels of infor- mation that allows electronic instruments and computers to communicate with each other. Through MIDI input, digital sounds and samples can be inputted into Pro Tools and can then be mixed and edited to the desired output.
Video Editing and DVD Authoring Software
The widespread availability of digital cameras and now phones with built-in camera devices combined with the massive popularity of sites like YouTube has led many to use video editing programs. These programs enable the user to modify their clips extensively, and like audio capture and editing software there are both consumer and professional offerings. DVD authoring is a process that many video editing programs include. More specifically it oversees the layout of the DVD: what clips will be used and how they will be played along with customization of the menu. After authoring the DVD via the program the user must burn it to an actual DVD for playback. This can be done using utilities included by Windows or Mac or by dedicated software. For large and expensive projects, editors need advanced software that has a multitude of features and can handle the scale of such projects. One professional video editing program is Final Cut Pro, created by Apple. This soft- ware has advanced tools and capabilities to edit and cre- ate videos and clips. The most recent version, Final Cut Pro X, has new features that make video editing easier and more efficient such as a new dynamic editing inter-
90 CHAPTER 3. SOFTWARE
Final Cut Pro X
face, new multichannel audio editing capabilities, more precise inline clipping tools, and a streamlined interface that helps to keep media organized. Professionals can use this software to create complex movies ready for the big screen.[50]
A Media Player
A standard film-editing program on Mac is iMovie. It is a standard free program, tailored toward light editing for simple movies. Apple markets it as an editing program for home movies [51]. It is a simple ti use system, in in- corporates file from the Internet, iTunes, iPhoto, garage band, and other online and Mac programs. While it is not at advanced as Final Cut Pro, it does do a good job editing movies. Mac has also added and iOS compatible version of the program for use on its mobile devices. This ver- sion is compatible with both the iPads, and iPhone prod- uct lines. However, iMovie’s capabilities are limited, as mobile devices lack the memory and processing power for extend editing of projects. Another feature built into iMovie is the ability to share directly to Internet websites. These include Facebook, twitter, and YouTube. In addi- tion, there is a quick feature for emailing movies. Once edited movies are formatted and finalized, Apple runs its own video player known as QuickTime. This is a stan- dard program, similar to Windows Media Player, and is compatible with both Macs and PC’s. Film editors like QuickTime as it is more reliable and has fewer bugs that Media Player, and it is less likely to corrupt video files. [[File:QuickTime 7 Icon.png|thumb|QuickTime 7 Icon]
Media Players
Living in the technologically advanced country that we do now, it is relatively understandable to say that, at some point or another in our life, we have all heard some form of music or audio played off of an electronic device. To- day, for most of us, these devises are things such as CDs, radios, iPods, phones, DVDs, and many more. These are all things that would be considered media players. They were designed with the purpose of playing audio or videos in mind. Today, many of these players are free and are programs that most of us have probably used at some point or another (such as iTunes or Windows Media Player). One thing it is important to keep in mind when using these is that although illegally downloading things may be easy, it definitely does not make it right. It is es- sential that we all keep the copyright laws in mind when downloading any type of audio or video.[52]
Graphics on a Webpage
Graphics, Multimedia, and the Web
Today, it is rare to find a company that does not use some form of multimedia or graphics on their businesses web page. This is just one example of how important multi- media and graphics have become to the World Wide Web. Open up you browser and instantaneously you’ll see some from of graphics spread across that front page. Whether it’s a banner, GIF, logo, demonstration, or picture, I can pretty much guarantee you that it’s there. These graph- ics are nice because they easily add color and animation to the page, and make being there just a little bit more interesting for the user.[53]
Other Types Of Application Software
There are many types of application softwares. Every type of application software is made to serve a func- tion or to help, for example software for business’ or ed- ucation. Desktop publishing refers to using a personal
3.17. REVIEW 91
Microsoft OneNote
computer to manipulate text and images to create attrac- tive documents as if they were created by a professional printer. Similar to this, personal publishing softwares are used to create documents for personal use, such as invi- tations, flyers, or calendars. Very common types of ap- plication software include education and entertainment. Entertainment software includes games, simulations, and other programs that provide amusement. Educational software can be found on personal computers, but a pop- ular trend is to combine the hardware and software into a single product. For example, Leapfrog is well-known for their child look-alike laptops used for teaching.[54] Software such as OneNote and Notebook are examples of note taking software. These softwares are generally used by students and businesspeople to take notes during lec- tures or meetings. Because of this, note taking software normally supports typed and handwritten input. Engi- neers and architects make use of design software such as CAD(computer-aided design). CAD plays an impor- tant role in the design of finished products and other fields such as art, advertising, or law.
3.17 Review
3.17.1 Key Terms
Application Software Software designed to carry out specific tasks [55]
Shareware Copyrighted software that is distributed on the honor system; consumers should either pay for it or uninstall it after the trial period for ethicality [56]
Freeware Copyrighted software that may be used free of charge [57]
Public Domain Software Software that is not copy- righted and may be used without restriction [58]
Open Source Software Software programs made up of source code which is made available to the public. i.e. Wikibook [59]
Web-Based Software Software that is delivered on de- mand via the Web; also referred to as Software as Service (SaaS) or cloudware.
Word Processing Using a computer and word pro- cessing software to create, edit, save, and print written documents, such as letters, contracts, and manuscripts [60]
Spreadsheet A document containing a group of values and other data organized into rows and columns; also called a worksheet in a spreadsheet program [61]
Database A collection of related data that is stored in a manner enabling information to be retrieved as needed; a collection of related tables [62]
Presentation graphics An image, such as a graph or drawn object, designed to visually enhance a pre- sentation
Graphics Software Application software used to create or modify images
Ribbon One of the features found in the recent Mi- crosoft Office applications that uses tabs to organize groups of related commands [63]
3.17.2 Accessibility Software
Visual Aid Software
There is software that enables a user to access software even if they have a disability of some type. The same software can simply allow a user to access programs on their computer without visual interferences. An example of this would be f.lux. F.lux is a program that removes the blue tint from a users screen in order to prevent headaches and the light interfering with circadian sleep rhythms [64]. These applications are particularly useful when reading or writing word documents in a dark room.
3.17.3 Review Questions
1. A _____ is a collection of worksheets saved in a single spreadsheet file. 2. A _____ is a collection of related data that is stored in a manner enabling information to be retrieved as needed.
92 CHAPTER 3. SOFTWARE
3. With a(n) _____ program, the source code for the pro- gram is made available to the public and so can be mod- ified by others. 4. True or False. Changing the font size in a document is an example of a formatting operation. 5. A _____ is a collection of related fields in a database. Also called a row. 6. Software that is not copyrighted and may be used with- out restriction is _____. 7. True or False. Software can be installed on both per- sonal computers and servers. 8. The location at the intersection of a row and column
on a worksheet into which data can be typed is a _____. 9. True or False. Microsoft Office is one example of a software suite. 10. Copyrighted software that is distributed on the honor system; consumer should either pay for it or uninstall it after the trial period is _____. Answers 1. Workbook 2. Database 3. Open Source 4. True 5. Record 6. Public Domain Software 7. True 8. Cell 9. True 10. Shareware
3.18 References [1] http://office.microsoft.com/en-us/word/
[2] http://www.corel.com/corel/pages/index.jsp?pgid= 12100162&storeKey=us&languageCode=en
[3] https://drive.google.com
[4] http://www.apple.com/iwork/
[5] http://office.microsoft.com/en-us/excel/
[6] http://www.apple.com/iwork/keynote/
[7] http://audacity.sourceforge.net/
[8] https://en.wikibooks.org/wiki/The_Computer_ Revolution/Software/Installed_vs.Web-Based_Software
[9] http://www.iplanner.net/business-financial/online/ how-to-articles.aspx?article_id=software-web-based
[10] http://stackoverflow.com/questions/111985/ what-are-the-cons-of-a-web-based-application
[11] http://www.nytimes.com/2012/11/18/business/ what-it-takes-to-be-an-app-developer.html
[12] Understanding Computers 14th Edition by Deborah Mor- ley
[13] http://www.smhllaw.com/articles/?p=319
[14] http://www.wisegeek.com/what-are-software-suites.htm
[15] http://www.techterms.com/definition/wordprocessor
[16] http://jan.ucc.nau.edu/~{}lrm22/technology/wpbasics/ wpbasics.htm
[17] https://en.wikipedia.org/wiki/Template_(word_ processing)
[18] http://www.aauwnc.org/04-05/convention/workshops/ tech/typewriter.pdf
[19] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013929
[20] http://www.theiia.org/intAuditor/ itaudit/archives/2006/january/ the-role-of-spreadsheets-in-todays-corporate-climate/
3.18. REFERENCES 93
[21] http://www.pcworld.com/article/2459947/ how-to-create-and-customize-tables-in-microsoft-word. html
[22] http://www.quepublishing.com/articles/article.aspx?p= 1649256
[23] http://office.microsoft.com/en-us/templates/
[24] http://en.wikipedia.org/wiki/Spreadsheet#Functions
[25] http://en.wikipedia.org/wiki/Spreadsheet#Functions
[26] http://office.microsoft.com/en-us/ overview-of-formulas-HA102748997.aspx
[27] http://office.microsoft.com/en-us/ overview-of-formulas-HA102748997.aspx
[28] https://support.office.com/en-MY/Article/ Create-a-PivotTable-to-analyze-worksheet-data-a9a84538-bfe9-40a9-a8e9-f99134456576
[29] http://www2.uncp.edu/home/acurtis/Courses/ ResourcesForCourses/Databases.html
[30] http://www.webopedia.com/TERM/D/database.html
[31] http://office.microsoft.com/en-us/access-help/ create-tables-for-a-new-database-RZ101772997. aspx?section=3
[32] http://en.wikipedia.org/wiki/Database
[33] http://www.tech-faq.com/what-is-a-database.html
[34] http://en.wikipedia.org/wiki/Query
[35] http://en.wikipedia.org/wiki/Crate_%26_Barrel
[36] http://en.wikipedia.org/wiki/Lord_%26_Taylor
[37] http://en.wikipedia.org/wiki/Database
[38] http://databases.about.com/od/administration/a/ choosing_a_db.htm
[39] http://www.zdnet.com/article/ the-top-ten-most-common-database-security-vulnerabilities/
[40] http://www.jiscdigitalmedia.ac.uk/guide/ pedagogical-uses-of-presentation-software
[41] http://whatis.techtarget.com/definition/ presentation-software-presentation-graphics
[42] https://www.boundless.com/communications/ preparing-and-using-visual-aids/ using-powerpoint-and-alternatives-successfully/ advantages-and-disadvantages-of-powerpoint/
[43] http://presentationsoft.about.com/od/ powerpointtipsandfaqs/f/ppt_overview.htm
[44] https://prezi.zendesk.com/forums
[45] http://www.globalspec.com/learnmore/industrial_ engineering_software/imaging_graphics_software/ drawing_software
[46] http://www.explainingcomputers.com/software.html
[47] http://audacity.sourceforge.net/
[48] https://en.wikipedia.org/wiki/Pro_Tools
[49] https://en.wikipedia.org/wiki/MIDI
[50] https://www.apple.com/final-cut-pro/what-is/
[51] http://www.apple.com/mac/imovie/
[52] http://www.computerhope.com/jargon/m/mediplay.htm
[53] http://www.billiondollargraphics.com/web.html
[54] https://en.wikipedia.org/wiki/Educational_software
[55] https://en.wikipedia.org/wiki/Application_software
[56] https://en.wikipedia.org/wiki/Shareware
[57] https://en.wikipedia.org/wiki/Freeware
[58] https://en.wikipedia.org/wiki/Public_domain_software
[59] https://en.wikipedia.org/wiki/Open-source_software
[60] https://en.wikipedia.org/wiki/Word_processing
[61] https://en.wikipedia.org/wiki/Spreadsheet
[62] https://en.wikipedia.org/wiki/Database
[63] https://en.wikipedia.org/wiki/Ribbon_(computing)
[64] Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Hu- mans
Chapter 4
Networks and the Internet
4.1 Computer Networks
4.1.1 Networking Applications
GPS Satellite NASA art-iif.crop
There are many different types of network applications. First and foremost is the internet, the largest network of networks in the world. Second, there are our phones, the oldest of which is POTS (plain old telephone service), which one day could be replaced by the newer technol- ogy, mobile phones. Mobile phones have been around for a few years now, and are beginning to replace home phone lines. Mobile phones can be separated into two groups, cellular phones and satellite phones. Cell phones work by communicating with cell towers in order to function. There are some dual mode phones which allow you to make phone calls through a WIFI signal, and switch to cell signal when out of WIFI range. Satellite phones work by communicating with satellites in space, this is primarily used with the military, where cell tower cover- age is nearly impossible in some locations. While satel- lite phones can be used in rural and mountainous arias, the drawback to them is when there is a storm or heavy
clouds, you can lose your signal. Satellites are also used with a GPS(global positioning system). GPS functions by relaying data between your device and the 24 satellites in space. They work similarly to sonar waves. The signal leaves the satellite, and depending on how long it takes to get to you will determine your exact location. In addition to tracking subjects, satellites and networks are beginning to play a larger part in the field of search and rescue (SAR). Most ocean going boats and all air- planes carry some kind of emergency beacon on board. Aircraft carry an emergency location transmitter (ELT) and boats carry an emergency position-indicating radio beacon (EPIRB). Before the mid 2000’s these devices transmitted on 121.5 mhz, the international emergency frequency, which was monitored by SAR satellites. How- ever, in 2009 [1], SAR satellites stopped monitoring 121.5 beacons in favor of the newer 406 mhz beacons. These devices guide SAR team to the site of a crash, but the signal is also embedded with data. This data includes the name of the owner of the beacon, the aircraft or ves- sel identification, and a precise GPS location. These ca- pabilities are also being used on personal locator bea- cons (PLB). These devices are small enough to carry in a pocket, but powerful enough to send an emergency sig- nal to a satellite. Hikers can use these if they are going to a remote area. The use of a satellite network allows for very precise tracking of these devices, and can bring rescue team to the site within two hours. Computer networks consist of two or more computers or hardware devices linked together to enable connections between shared hardware, software, and data. A combi- nation of networks that consist of telephone networks and computer networks are also becoming more commonly used in this generation.[2] The data is able to be passed along to other networks due to networked computing de- vices along data connections. A datagram, segment, or block is a unit of communication over a digital network, commonly known as a packet. The data breaks down into smaller units of data when needed. Once the data trav- els along the data connections, the pieces of data are re- assembled into the original data chunk. Data is structured differently, depending on the protocol enforcing the data. The structure of a packet consists of a header and a pay- load. The header consists of titles regarding transmission-
94
4.1. COMPUTER NETWORKS 95
A Common PLB
related information. The payload, however, consists of the actual data the packet is carrying.[3] Computer net- works range from small private networks, to large com- puter networks. The Internet, or the World Wide Web, is the largest computer network, consisting of a system of interlinked hypertext documents accessed via the In- ternet. Via hyperlinks, a user of the Internet can access images, text, videos, etc.
RFID chip
Monitoring Systems are another form of networking ap- plications. These systems specialize in locating a specific person, vehicle or device rather than pulling up geograph- ical information like a GPS does. However, most mon- itoring systems use GPS in locating their targets. Radio Frequency Identification (or RFID) for example, can be used to locate a person or animal with an RFID chip em- bedded inside of it. Most commonly recognized for it’s
ability track pets that have the chip implanted, RFID has also moved into the human medical field. In fact, some breast implants in the United Kingdom have been chipped so that a physician can read information about the implant years after the surgery has been completed.[4] While this is the social reasoning for this type of chipping, it seems that medical records housed on inexpensive servers would suit this purpose just fine. The fact remains that RFID chips, which are about the size of a grain of rice, oper- ate using a small silicon chip and a copper antenna which emit personal information about it’s owner. This infor- mation is then picked up by electronic networks feeding back information about the product, the person carrying it, and it’s location to the network. It’s currently being used to track cattle and Alzheimer’s patients as well as merchandise produced by manufacturers.[5] Other moni- toring systems include vehicle tracking software such as the famous OnStar. This type of networking application has been expanded so that employers can spy on employ- ees using company vehicles. With a simple installation, the latest vehicle tracking applications can feed informa- tion about the geographic location of a company vehicle, the speed of the vehicle, and even “hard breaking” events. Mobile phones aren't omitted either. Since most of the current mobile phones have stand alone GPS systems a person can track the movements of the individuals under their plan as well as their own phone if it is stolen.[6]
A video conference.
Multimedia networking has exploded as well. This type of networking offers digital multimedia content such as movies, music, and recorded t.v. shows to be viewed over a phone, p.c., or television. While most devices already have the required capabilities built in, some devices need may need a receiver. Placeshifting is common with this type of network which will allow an individual to down- load content from one place and view it in another, i.e. from a t.v. to a mobile phone. Similarly, VideoConfer- encing allows people to interact remotely from separate locations. Instead of streaming a movie in real time, a person can stream a video feed from a relative or business part who might be across the globe. They can then inter- act and speak as they normally would while viewing the mannerisms of others in real time. Also, through the use of videoconferencing Telemedicine has been used to di- agnose and treat patients who are unable to access a doc- tor in person because of their poverty level, geographical area, or physical condition. Physicians, with the assis-
96 CHAPTER 4. NETWORKS AND THE INTERNET
tance of a member on site with the patient, use videocon- ferencing to conduct tests such as simple ear and throat checkups to procedures as complex as actual surgery in some cases.[7]
One relatively new use of networking is telesurgery, or remote surgery. As the name implies, this is surgery that takes place over distances: that is, the surgeon is not ac- tually in the same room as the patient. A surgeon con- trols robotic arms that in turn perform surgery on the patient. Some advantages of this kind of procedure are that it mitigates the potential effect of a surgeon’s hands shaking, the surgeon’s arms rest comfortably throughout the entire procedure, and the surgeon can specify a task that (s)he wishes to have performed and ensure it is safe before the robotic arms actually carry it out. Initially, there was just computer-assisted surgery, where the sur- geon sat only a few meters away, but now longer-distance telesurgery has been developed: the first telesurgical pro- cedure was known as Operation Lindbergh and involved a New York doctor performing on a French patient across the Atlantic. Telesurgery still isn't especially widespread, but in time, it may see such uses as performing on astro- nauts in long-term space travel, performing on soldiers on or near battlefields, or working alongside or training surgeons in remote, developing countries. Time will tell how useful these kinds of procedures turn out to be, but they are definitely an example of a networking technol- ogy that would have been unthinkable just a few decades ago.[8]
4.2 Network Characteristics
Networks can contain many different characteristics that define how they function as well as their capabilities. These characteristics include certain factors such as topology, scalability or size, architecture, and media.[9]
4.2.1 Network Topology
Bus Topology
Network topology is how different nodes in a network are connected to each other and how they communicate.
The five most common topologies are mesh topology, star topology, bus topology, ring topology, and tree topology. In a mesh topology, devices are connected with many excessive interconnections between network mode. In a star topology, the devices are connected to a central computer, and the nodes communicate across the net- work by passing data through the hub, which is the central computer. In a bus topology, it connects all devices on a local-area network called LAN. Bus networks are not very pricey, and they are easy to install. In a ring topol- ogy, it consists of a local area network whose topology is a ring. The messages travel around the ring. In a tree topology, it is considered a “hybrid” topology that com- bines characteristics of the bus and star topologies.[10]
4.2.2 Network Architecture
Server-based-network
Network architecture is the layout of the network. The hardware, software, communication protocols, and mode of transmission in the network architecture.[11] Two main types of network architectures are server-based, or client-server networks, and peer-to-peer (P2P) net- works. Server-based networks consist of clients and servers. Servers are powerful computers that are able to transfer data and information among personal comput- ers within the local network or even to other computers across the Internet.[12] Some server-based networks can be designed for certain purposes such as to connect all computers within a given area to a printer (print server) or to even contain data such as documents or other types of files (file server). A peer-to-peer network is a network that doesn’t utilize a central server. Instead, each com- puter (or peer) within a peer-to-peer network allows it- self to use some of its resources to share with the entire network. For example, computers can give some of their processing power or bandwidth and share it with the net-
4.2. NETWORK CHARACTERISTICS 97
work participants.[13] The network architecture plays an essential role in today’s society; therefore, one should be aware of the network architecture, and the different types of network topologies as well.
4.2.3 Network Size
Network sizes are defined by a few three-letter acronyms: PANs, LANs, MANs, and WANs. Personal Area Net- works (PANs) are networks that connect an individual’s devices, such as bluetooth headsets and speakers. Local Area Networks (LANs) are networks that are used within larger areas such as corporate buildings but can also be used in hospitals or even college campuses. Some peo- ple, however, prefer to title networks on a college cam- puses and hospitals as Campus Area Networks (CANs) if they contain more than one LANs interconnected. A Metropolitan Area Network (MAN) is used to connect computers within cities. Lastly, a Wide Area Network (WAN) is a network that contains numerous LANs and is able to connect computers across continents. The largest Wide Area Network is the Internet. Some people use other terms such as Global Area Network (GAN) which is a single network with connection points across the globe, usually used to connect large corporation, or Solar Sys- tem Area Network (SSAN), which is numerous GANs, combined to connect planets within a single solar system. This technology, however, is not yet available.[14]
4.2.4 Network Media
Network media is the actual path which the signals travel to and from different components. These paths can either be physical wires, wired media, or radio signals, wireless media.[15]
Wired Networking Media
The wire used for networking media is called cable. The most common types of wired media include twisted-pair, coaxial, and fiber-optic cable.[16]
Twisted-Pair Cable Twisted-pair cable is exactly what it sounds like: two wires twisted together. This design works because it creates an electrical current that flows through the wire, which creates a circular magnetic field around the wire that increases performance. Having the wires twisted, as opposed to being adjacent, helps there to be no crosstalk (the noise/interference sometimes gen- erated by the wires). There are two sub-types of twisted- pair cable: unshielded twisted pair (UTP) and shielded twisted pair (STP). Twisted-pair cable is most used for LANs such as telephone communication.[17]
plastic jacket
dielectric insulator
metallic shield
centre core
Coaxial cable cutaway
Coaxial Cable Coaxial cable is made of three com- ponents: the inside wire, the insulation, and the outside shield. The inside wire is made of two conducting el- ements, mainly copper and covering this is the layer of flexible insulation. A second layer of woven (braided) copper or metallic foil that acts as a second wire and as a shield that reduces that amount of outside interference. Lastly, there is a cable jacket to cover the second wire.[18]
Fiber-optic Cable Fiber-optic cable is made of hun- dreds of clear glass or plastic fiber strands that are the size of a human hair. Data is transferred by light pulses at speeds of billions of bits per second. This is the newest and fasted type of cable, and while it is the most expen- sive, it is starting to replace the other types because its high-speed advantages are considered to be worth it.[19]
Wireless Networking Media
Mvdl-logo
Along with wired networks, there are also wireless net-
98 CHAPTER 4. NETWORKS AND THE INTERNET
works. Wireless networks are networks that use radio signals to transmit data through the air in order for two or more devices to communicate, rather than physical ca- bles. This gives people the opportunity to use e-mail or browse the internet from almost any location, provided there is a wireless network available. Many devices today are able to use this technology such as PCs, laptops, mo- bile devices, servers and printers. Wireless networks can be found almost everywhere including the home and pub- lic locations such as libraries, restaurants, coffeehouses and airports. Many people needing Internet access on the go will commonly take advantage of wireless hotspots. A wireless hotspot is a small range area with a usable con- nection that allows access to the internet. There are also different types of wireless networks. Wire- less Local Area Networks (WLANS) are networks that give access to the Internet to a small local area such as a college or library. Wireless Personal Area Net- works (WPANS) allow connectivity of devices in smaller ranges, typically around 30 feet. This includes Infra Red technology which may be in a television remote, or Bluetooth. A Wireless Metropolitan Area Network (WMANS) allows for the connection of many networks in a metropolitan area such as in high-rises or big build- ings. Wireless Wide Area Networks (WWANS) are net- works that spread over much larger areas such as cities or countries and are available through the use satellite sys- tems or antenna sites.
Wired Vs. Wireless Networking Media
This does not look attractive in a business setting.
While the world may be going towards a wireless route when it comes to networking, is it really the best direction when it comes to connectivity? Let’s break it down to the benefits and disadvantages of each type of network media. The benefits of having wired connection are that it it’s se- cure, reliable, and fast. They are also very much cheaper than having wireless connections. Another perk, espe- cially for businesses or enterprises, is that wired connec- tions can be controlled. This has security and productiv-
ity benefits. Disadvantages of wired connection are the sacrifice of space and portability or mobility, as well as actual physical safety and maintenance.[20]
This may look cool but is it safe?
The benefits of having wireless connection are the ac- tual lack of cables. This gives freedom to use personal as well as office devices and actual physical freedom. An- other thing is that it just looks a lot neater than a bunch of wires. Disadvantages though are in terms of security, slower speeds, and sometimes unreliable coverage. The best combination would probably to have a sort of system with some wired connections and some wireless connections. Having a mixed environment may be just enough to balance out the disadvantages and take advan- tage of the benefits of having both types of networking media.[21]
4.2.5 Types of Cables
There are different types of cables. The cables that con- nect a computer, or network or computers, to a server or router or modem are called ethernet cables. The evolu- tion of ethernet cables started when it became apparent that coaxial cables were not able to keep up with the de- mands of ever-growing and evolving networks. The ca- bles are listed in categories or “Cat” for short. The Cat 1 cables were primarily used for telephone modems and had a data transfer rate of up to 1Mbps. Cat 2,3,and 4 can all support computer networks and telephone traffic, and have maximum capacities of 4Mbps, 10Mbps, and 16Mbps respectively. When these cables are taken out of their casing, they look very similar. The same wires are present in all types of Cat cables; however, the number of wraps per inch increase in each version of Cat cables, therefore decreasing the amount of electromagnetic inter- ference in the signal being transfered. The introduction to Cat 5 revolutionized networking because Cat 5 became the standard and it was classed as “ethernet” which means that it has the capability for high speed and high capac- ity data transfers (of 10Mbps - 100Mbps), as well as the ability regulate the transfers in order to prevent simulta- neous transfers which would cancel out. After Cat 5, Cat 5e was introduced. The “e” stands for “enhanced”. The
4.2. NETWORK CHARACTERISTICS 99
Cat 5e “gigabit” cable - in theory - had the capacity for 1000Mbps (1 gigabit) transfer rates. This was accom- plished by wrapping the strands of wire tighter, therefore cutting down on “crosstalk” or interference that caused disruptions in the data transfer. Later, Cat 6 was intro- duced which added a physical separator inbetween stands of wire in the cable which lowered interference more yet and has transfer capacities of 1000Mbps (1 gigabit per second).[22] Since 2013, Cat 7,8, and 8.1 have been in- troduced, but are only practical in a small amount of in- dustrial settings.
4.2.6 Network Architecture & Network Topologies
Bus Topology
Network architecture is the layout of the network. The hardware, software, communication protocols, and mode of transmission consists in the network architecture. The network architecture plays an essential role in today’s so- ciety; therefore, one should be aware of the network ar- chitecture, and the different types of network topologies as well.[23] Network topology is how different nodes in a
network are connected to each other and how they com- municate. The five most common topologies are mesh topology, star topology, bus topology, ring topology, and tree topology. In a mesh topology, devices are connected with many excessive interconnections between network mode. In a star topology, the devices are connected to a central computer, and the nodes communicate across the network by passing data through the hub, which is the central computer. In a bus topology, it connects all devices on a local-are network called LAN. Bus net- works are not very pricey, and they are easy to install. In a ring topology, it consists of a local area network whose topology is a ring. The messages travel around the ring. In a tree topology, it is considered a “hybrid” topology that combines characteristics of the bus and star topologies.[24]
4.2.7 Data Transmission Characteristics
Data Transmission
Analog signal
Data transmission is the actual transfer of data through a channel. The types of channels are copper wires, optical fibers, wireless communication channels, storage media and computer buses. This data transfers through a sig- nal, either electrical, radio wave, microwave, or infrared. Data can be transferred by analog transmission using ana- log and digital signals. The modem is able to receive the digital data and change that digital data and process it. The data transmitted can be from a keyboard, which is the data source. The data transmitted can also be analog though like from a cell phone that can be digitized using source coding. Source coding are computer instructions that are read and interpreted by the computer.[25]
Bandwidth
Bandwidth is the amount of data that can be transmitted in a certain amount of time. Bandwidth is also referred to as throughput. The most common measure of band- width is bits per second (bps), but it is also measures in
100 CHAPTER 4. NETWORKS AND THE INTERNET
−3 dB
f1 fc f2
Bandwidth
Kbps, which is thousands of bits per second; Mbps, which is millions of bits per second; or Gbps, which is billions of bits per second.[26] Bandwidth is the capacity of the connection. A network medium with a higher bandwidth will allow more data to pass through in a certain amount of time. So the greater the capacity, the better the per- formance will be. This isn’t always true though because performance depends on other things too. Text data re- quires the least amount least amount of bandwidth and video data requires the most.[27]
Analog vs. Digital Signals
The red is a digital signal and the gray would be an analog signal
Analog and digital signals are used to transmit informa- tion, usually through electric signals. Analog signal is a continuous signal and has constant fluctuations where a digital signal is discrete time signals generated by digi- tal modulation. Analog signals are denoted by sine waves that are smooth and continues whereas digital signals are square waves that are stepping and discrete.[28] Analog signals would be things like human voices in the air and analog electronic devices (AM and FM radio, old tele- phones). Digital signals have only two levels of voltage: high and low.[29] It is an electrical signal that is converted into a pattern of bits. It has a discrete value at each sam- pling point. Each sample is defined with a series of bits that are either 0s or 1s. Digital signals are for things like computers, CDs, DVDs, and other digital electronic de-
vices. Analog signal processing can be done in real time and consumes less bandwidth whereas there is no guar- antee that digital signal processing can be done in real time and consumes more bandwidth to carry out the same information. The advantages of digital signal are that the recording does not degrade over time and groups of numbers can often be compressed by finding patterns in them.[30]
Transmission Type and Timing
Network Data Transfer
For the transfer of data and networking media, there can be two ways to send information. Serial transmission is data sent in a single path, one bit at a time. An exam- ple of this would be a classroom of students lining up single file at the door and exiting one by one. The advan- tages of serial transmission is that the only use one line so it is less expensive, for the line at least, compared to parallel transmission which uses multiple lines. Disad- vantages would be the cost of total transmission. Serial transmission is also not as fast since the bits are trans- ferred sequentially.[31] Parallel transmission is data sent one byte at a time, but each bit in the byte takes a separate route. This is a more efficient way of sending or receiving data. For instance, parallel transmission can be identified as students walking through a large hallway in a school to get to their specific classrooms. This way, there is more space involved, in order for the data to be received more efficiently. However, most networking media usually use serial transmission. Synchronous, Asynchronous, and isochronous transmis- sion are three different ways that serial transmission is transferred. Synchronous transmission is ordered into groups and blocks of data that are transferred one af- ter the other. Advantages of synchronous transmission is that is faster but the disadvantages are buffering and making sure the sender and receiver have the same clock frequency.[32] Asynchronous transmission is not used as much as synchronous because it is sent when it is ready. The data is not synchronized which makes the end re- sult less efficient.The advantages of Asynchronous trans- mission is that this method is cheaper only if the line are shorter since the idle time would be low. Each charac-
4.2. NETWORK CHARACTERISTICS 101
ter that is sent will not be messed up in the process since they are all separate. There can be different bit rates for the signal, and transmission can start as soon as possi- ble. Disadvantages of Asynchronous would be it is less efficient and slower because of the gaps between bits.[33] Isochronous transmission sends the data all at once. Data can also travel in mainly three distinct ways. Sim- plex transmission is when the data is traveling in only one direction. Half-duplex transmission sends the data in ei- ther direction, but data can be sent only in one direction at a time. Full-duplex transmission sends the data back and forth in either direction and can be simultaneous.
Delivery Method
Data is delivered by using circuit switching, which is a specific path between a sender and a receiver. A tele- phone system is an example of circuit switching because the path is dedicated to only those two people for the time being. Once they are off the phone, the path is free to use by whomever else. Sending data over the Inter- net is called packet switching. The messages sent are de- tached in “packets.” While traveling through the Internet, the packets contain all information going from the sender to the receiver. Once the transmission is complete, the packets are put back together to create the correct mes- sage.
Signature Characteristics
Characteristics include the physical transfer of data, or a digital bit stream or a digitized analog signal, through a point-to-point communication channels (copper wires, optical fibers, storage media and computer buses). Data is represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared sig- nal. Its messages are symbolized in one of two ways. The first, known as baseband transmission, is completed by a sequence of pulses using a line code. The second, pass- band transmission, utilizes a specified set of continuously varying waveforms, created using a digital modulation method. Regardless of which technique is used, the re- ceiver must synchronize itself with the transmitter. There are two distinct types of transmission -- Asynchronous and synchronous. In asynchronous, the two devices are relatively close to each other in speed. This means that if only small bursts of data are sent at a time, its synchro- nization will be successful as long as the receiver is able to synchronize with the immediate beginning of the data burst. In synchronous transmission, a significantly larger amount of data is sent in each block, which either con- tains, is preceded, or accompanied by signaling, thus per- mitting co-synchronization of the devices. The majority of all network backbone traffic today is synchronous.[34]
4.2.8 Communications Protocols and Net- working Standards
The definition and usage of TCP/IP
This is a visual representation of how all the IP addresses are connected to each other
Example of Ethernet Cord
Communications protocol and networking standards are necessary in order to determine how devices on a net- work communicate and what requirements are needed in order for hardware and software manufacturers to de- velop computing products that function with other prod- ucts. Techopedia, an online source of computing devices, explains communication protocol as “formal descriptions of digital message formats and rules. They are required to exchange messages in or between computing systems and are required in telecommunications.”[35] Protocol deals
102 CHAPTER 4. NETWORKS AND THE INTERNET
with issues concerning packet size, transmission speed, packet sequence controls, routing, and address format- ting. These are just some of the many things that protocol and standards deal with in computing devices. Some pop- ular protocols include File Transfer Protocol (FTP), Hy- pertext Transfer Protocol (HTTP), and Post Office Pro- tocol (POP3). There’s little argument that the most popu- lar communications protocol being used today is TCP/IP. The protocol that’s used for transferring data over the In- ternet, TCP/IP is actually a combination of two proto- cols. The TCP part of the equation stands for Transmis- sion Control Protocol and it is culpable for data delivery. IP stands for Internet Protocol and it provides routing in- formation and addresses. There are several reasons for the continued popularity of TCP/IP. One of these rea- sons is the flexibility of the dual protocols, as the core has been able to remain largely the same over 25 years, even with the immense growth of internet popularity. An- other reason is the routing design, as TCP/IP is designed specifically to facilitate the routing of information over a network of arbitrary complexity.[36] Pretty much all op- erating systems have built in support for the TCP/IP pro- tocols so that is also a big factor in their popularity. One potential controversy related to IP’s in particular was the scare when the Internet had run out of Internet ad- dresses. The original IP version, called IPv4, had used up all the potential number combinations so no new folks would have been able to connect to the internet... that is, until IPv6 came out. It uses 128 bit addresses, versus the mere 32 bits of IPv4, ensuring that it will be another long time to go until we risk running out of internet addresses again.[37]
Ethernet (802.3) is the most widely used standard for wired networks. It is typically used in local area network- ing (LAN) with twisted-pair, coaxial, or fiber-optic ca- bling. There are many standards of Ethernet and each of those standards reaches a maximum speed. Terabit Eth- ernet standard is the most current standard that is being developed and improved. It will be used to deliver video, digital X-rays, and other digital medical images. In or- der for a device to be connected to an Ethernet network, the device needs to have an Ethernet port built into the device or added with an expansion card. Power over Eth- ernet (PoE) allows for electrical power to be set along in the cables of an Ethernet network. This is what allows security cameras to get electrical power while also main- taining a network connection.
Wi-Fi Standards (801.11)
Wi-Fi, which uses the IEEE standard 802.11, is a very popular wireless networking technology that uses radio waves to provide wireless Internet connection to devices. It is perhaps the biggest theme that today’s technological generation revolves around. With the continuous evolv- ing technology, almost every single mobile device now requires an Internet access, or a wireless network stan-
Hotspots with a Wi-Fi network will have this sign to attract and please customers.
dard like Wi-Fi. Due to this, Wi-Fi hardware is built into virtually all portable computers, mobile devices, and even other portable products like printers, digital cam- eras, gaming consoles, etc. Consequently, the popular- ity of a Wi-Fi network in houses, businesses, and pub- lic hotspots—airports, hotels, coffee shops—has grown steadily. Supporting “roaming,” devices connected to a Wi-Fi network are able to move from one access point to another, as long it is inside or around the actual building or area. The speed and strength of a Wi-Fi network de- pends on various factors like the Wi-Fi standard or the hardware being used. For example, the most widely used Wi-Fi standards today are 802.11g and 802.11n. The 801.11n, the newest Wi-Fi standard, is in fact currently the fastest standard today, which is able to transfer data five times as fast as the 802.11g standard. However, even though Wi-Fi seems like the next best technological invention after computers and the Internet, it does have some minor disadvantages that limit the ulti- mate use of it. For example, Wi-Fi networks have a lim- ited range; one will lose the connection to a network if they move out of the range of that network, usually 300 ft. away from the actual router. They would then have to connect to the next available Wi-Fi connection. An- other limitation of Wi-Fi is that many businesses may be physically too large for a conventional Wi-Fi network to cover the entire area. However, there are special network- ing connections known as WiMAX or Fixed WiMAX, that provide Internet access for a longer radius, stretch- ing from 2 to 6 miles. Using multiple WiMAX towers, similar to cell phone towers, it is even possible to provide coverage to an entire city or any geographical area! [38]
Cellular Standards
It is no secret that the technology used for mobile phones has vastly evolved over the years. What started out as basically a mobile brick has quickly transformed into a compact, highly productive, and speedy cellular com- munication device. However, many people are unaware
4.2. NETWORK CHARACTERISTICS 103
Long Term Evolution Logo
of the generational breakdown of these devices. When the first generation mobile phone was released decades ago in the 1980s, it was produced with only the pur- pose of voice communication in mind. It was not until the second generation came out years later, around the 1990s, that we started to see both data and voice com- bined into one device. This generation is best known for its access to both Global System for Mobile com- munications (GSM) and Code Division Multiple Access (CDMA) which greatly work to enhance speed and com- munication up to 14.4 Kbps. When the third generation came along in the 2000s, we saw companies start to use packet switching and access speeds as fast as 2 Mbps. This brings us to where we are today. Cellular compa- nies across the globe are starting to utilize 4g technology and offer outstanding speeds of up to 20 Mbps. Though 20 Mbps is a lot faster than 3G’s speeds, which can be as low as 3.8 Mbps, it is not at the specified 100 Mbps that fourth generation phones are supposed to require. Fourth generation phones are using the LTE, Long Term Evo- lution, technology or the WiMAX technology, both of which allows for more capacity and faster speeds across the mobile network.[39] These two technologies are in- compatible to each other and it depends on which mobile phone provider that you are using. Currently, Sprint is using 4G WiMAX, while Verizon and AT&T are using 4G LTE.[40] This is a necessity in today’s world as more and more people buy mobile smart phones and demand a very high amount of data to be transferred to and from their phones. These technologies use OFDM, orthogo- nal frequency-division multiplexing, instead of TDMA, time division multiple access, or CDMA, code division multiple access. This change in technologies is what the mobile phone market accepts as a difference between the third generation and fourth generation of phones because OFDM is significantly faster and more efficient, even though it is not as fast as the original specification.[41] Another plus for the fourth generation phones is that they can still access broadband Internet content that many con- sumers vie for. Hopefully in the near future, technology companies can actually provide mobile phone consumers with a phone that will reach speeds up to 100 Mbps. With technology constantly evolving and expanding, where will it take us next? Into what technological wonders is fifth generation technology going to bring us? [42]
Wireless Printers
A common printer
Wi-Fi is one of the most popular networking standards that uses wireless LANs. Certain devices come Wi-Fi enabled and some can be hooked up within the wire- less network. One of the most popular devices being used today is the wireless printer. Not any printer can be used, however. Special printers nowadays have the Wi-Fi transceivers built into them to locate the available networks. The major advantage is that multiple comput- ers can print to a printer in any location that you want. Another great advantage is that you can avoid the painful cable clutter that comes with all of the devices you could hook up to the computer. It takes much less time for a computer to connect to the printer through Wi-Fi then it does to download the software and connect it manually with a USB cord. One thing to consider though is how windows and doors might affect the strength of the signal. Security is something to think about as well. Some print- ers contain a WPA (Wi-Fi Protected Access) encryption that allows only special computers to connect if they acti- vate the similar feature.[43] Believe it or not, these types of printers are actually reasonably priced compared to some of the other types of electronics out there on the market.
4.2.9 Networking Hardware
Network adapters or “Network Interface Cards,” (NICs) are used to connect a computer to a high-speed network. Most recently manufactured motherboards have them already built in. Otherwise, a NIC may be installed onto an open PCI expansion slot on the mother- board. Modems are able to convert your computer’s digital data to analog data that can be sent over telephone service lines and converts incoming analog data to digital data that the
104 CHAPTER 4. NETWORKS AND THE INTERNET
Network Adapter preferences
computer can work with. The better quality modems are able to do the work directly on the card. They are known to be faster and more efficient than a cheaper modem, go figure![44]
Cisco Model EPC3010
The term modem is short for modulator/demodulator. Modems are used to connect with internet services providers. They transfer data between the internet ser- vice provider and the computer. There are a few differ- ent types of modems available. Analog modems can be used with dial-up connections. Digital subscriber line or DSL and cable modems are used with high speed broad- band connections. Integrated services digital network, or ISDN modems are used for even higher speed connec- tions. [45]
Wireless routers have changed drastically in recent years. Once just a simple tool to broadcast the internet into a home or an office, today many wireless routers have addi- tional functions and capabilities. They can offer multiple frequencies to help avoid interference. They can be setup to allow guest access to the network. Some even allow for the advanced security setup with enhanced features like parental control to limit access to certain websites. Another convenient feature is the addition of storage to
the device. Some routers allow connection of external storage devices, while others have storage built in. Many routers also have mobile apps designed to control them. In the age of tablets and smartphones, the ability to con- trol your network settings via a mobile device is key.
Hardware for Connecting Devices and Networks
A wireless router
There are different configurations used in connecting de- vices to a network as well as connecting networks to other networks. An example of a configuration for a home net- work is a star topology where there is one central device that provides a connection for other devices. This central device, or hub, is not as efficient regarding the availabil- ity of bandwidth between the devices, specifically com- puters, that are connected to the hub. More exactly, the hub can lead to unnecessary traffic build-up because it repeats everything it receives to other devices. This may or may not be an issue depending on the size of the net- work. A small network will not have much issue with using a hub for a central device, but for other, larger net- works a different device may be more practical. A switch is more suitable for larger networks. Like hubs, switches allow devices to communicate with each other. However switches contain ports that are designated for individual devices, which allows for a more efficient allocation of bandwidth for the devices as a whole.[46]
Routers are used to connect different networks together. [47] Because they maintain configuration information in a storage known as a routing table, routers can filter incom- ing or outgoing traffic.[48] Wireless access points are de- vices that allow a device access to the network. This, along with a switch, can be found in wireless routers. These routers connect both wired and wireless devices to a network, which then connects that network to the Inter- net. Another device is a bridge, which simply joins two LAN segments. An example of this would be connecting a game console to a home network.
4.2. NETWORK CHARACTERISTICS 105
Satellite dish
Repeaters, Range Extenders, and Antennas
Network repeaters regenerate incoming electrical, wire- less or optical signals. Today, most data transmissions rely on Ethernet or Wi-Fi, both of which can only span a limited distance before the quality of the signal degrades. The goal of the repeater is to help preserve a tolerable signal over long distance while examples like Ethernet or Wi-Fi have trouble to.[49] While repeaters are available for both wired and wireless networks, repeaters for wire- less networks are referred to as range extenders. Range extenders are commonly found in homes in order to elim- inate “dead zones”, or areas where the normal network doesn't offer coverage. A range extender will typically wirelessly connect to the network, then repeat the wire- less signal. One of the most reliable and popular ways of increasing the range of a network is through the use of an antenna. Antennas are highly effective because of their ability to convert radio-frequency into alternating current, or vice-versa. The most common type of antenna is the dish antenna, which is used for satellite communications. An example of antennas being used can be seen on an ev- eryday home rooftop, where dish-like antennas are often used for television signal [50]
4.2.10 Review
Review Definitions
Analog signal: A type of signal where the data is repre- sented by continuous waves. Bluetooth: A networking standard for very short-range wireless connections; the devices are automatically con- nected once they get within the allowable range. Bus Network: A network consisting of a central cable to which all network devices are attached.
Coaxial Cable: A networking cable consisting of a cen- ter wire inside a grounded, cylindrical shield, capable of sending data at high speeds. Ethernet (802.3): A widely used wired LAN networking standard. Extranet: An intranet that is at least partially accessible to authorized outsiders. Fiber-Optic Cable: A networking cable that utilizes hundreds of thin transparent fibers over which lasers transmit data as light. Intranet: A private network that is set up similar to the Internet and is accessed via a Web browser. Local Area Network (LAN): A network that connects devices located in a small geographical area, such as within a building. Mesh Network: A network in which there are multiple connections between the devices on the network so that messages can take any of several possible paths. Modem: A device that enables a computer to communi- cate over analog networking media, such as connecting to the Internet via telephone lines. Parallel Transmission: A type of data transmission in which bytes of data are transmitted at one time, with the bits in each byte taking a separate path. Router: A device that connects multiple networks to- gether; routes packets to their next location in order to efficiently reach their destination. Serial Transmission: A type of data transmission in which the bits in a byte travel down the same path one after the other. Virtual Private Network (VPN): A private, secure path over the Internet that provides authorized users a secure means of accessing a private network via the Internet. Wireless Network: A network in which computers and other devices are connected to the network without phys- ical cables; data is typically sent via radio waves.
Review Questions
1.) Third generation computers became smaller and more reliable than earlier computer generations, incorporating multiple transistors and electronic circuits on a singles tiny silicon chip by utilizing ______________. 2.) A small business needs a computer that can act as a server for a number of PCs and handle a number of users running different applications. The class of computer best suited to its needs would be a(n) __________ 3.) Programs designed to perform specific tasks or applications, such as computing bank-account interest, preparing bills, or creating letters, are contained in ____________
106 CHAPTER 4. NETWORKS AND THE INTERNET
4.) An example of system software is __________________ 5.) PC-compatible and Mac are the two major personal computer ____________ 6.) The purpose of a computer network is to allow com- puters to _____________ 7.) Computers and the traditional devices that we use every day- such as the telephone, TV, and home enter- tainment system- have begun to merge into single units with multiple capabilities; this trend is referred to as ____________ 8.) Having a basic understanding of computers and their uses is called _______________ 9.) The four main computer operations are input, output, storage, and _________ 10.) A mobile device based on a mobile phone that can be used to access the Web and e-mail wirelessly, as well as other capabilities such as taking digital photos, is often referred to as a(n) ___________
Review Answers
Answers 1.) Integrated Circuits 2.) Midrange Server 3.) Application Software 4.) Windows 5.) Platforms 6.) Communicate with each other, share software, and share hardware 7.) Convergence 8.) Computer Literacy 9.) Processing 10.) Smartphone [51]
[1] http://www.aopa.org/News-and-Video/All-News/2009/ January/22/Whats-up-with-121-5-MHz-ELTs
[2] http://www.webopedia.com/TERM/N/network.html
[3] http://voip.about.com/od/glossary/g/PacketDef.htm
[4] http://www.rfidjournal.com/articles/view?11093
[5] http://electronics.howstuffworks.com/gadgets/ high-tech-gadgets/rfid.htm
[6] http://www.caranddriver.com/features/ vehicle-tracking-systems-and-data-recorders-tested-gearbox
[7] http://www.americantelemed.org/learn
[8] http://www.surgeryencyclopedia.com/St-Wr/ Telesurgery.html
[9] http://computernetworkingnotes.com/ network-security-access-lists-standards-and-extended/ network.html
[10] http://www.webopedia.com/DidYouKnow/Hardware_ Software/Networking/tree_topology.html
[11] http://en.kioskea.net/faq/ 2761-what-is-network-architecture
[12] http://compnetworking.about.com/od/ basicnetworkingconcepts/g/network_servers.htm
[13] https://en.wikipedia.org/wiki/Peer-to-peer
[14] http://therealping.wordpress.com/2008/01/30/ network-sizes/
[15] Understand Computers Today and Tomorrow 14th Edi- tion Comprehensive
[16] Understand Computers Today and Tomorrow 14th Edi- tion Comprehensive
[17] http://www.ciscopress.com/articles/article.asp?p= 31276&seqNum=3
[18] http://www.ciscopress.com/articles/article.asp?p= 31276&seqNum=3
[19] Understand Computers Today and Tomorrow 14th Edi- tion Comprehensive
[20] http://smallbusiness.chron.com/ disadvantages-wired-technology-17833.html
[21] http://www.computerweekly.com/feature/ Wired-vs-wireless-in-the-enterprise
[22] http://www.firewall.cx/networking-topics/ cabling-utp-fibre/112-network-cabling-utp.html
[23] http://en.kioskea.net/faq/ 2761-what-is-network-architecture
[24] http://www.webopedia.com/DidYouKnow/Hardware_ Software/Networking/tree_topology.html
[25] https://en.wikipedia.org/wiki/Data_transmission
[26] http://searchenterprisewan.techtarget.com/definition/ bandwidth
[27] http://compnetworking.about.com/od/speedtests/g/ bldef_bandwidth.htm
[28] http://www.diffen.com/difference/Analog_vs_Digital
[29] http://en.wikibooks.org/wiki/Analog_and_Digital_ Conversion/Analog_vs_Digital
[30] http://www.diffen.com/difference/Analog_vs_Digital
[31] http://ecomputernotes.com/computernetworkingnotes/ communication-networks/data-transmission
[32] http://ecomputernotes.com/computernetworkingnotes/ communication-networks/data-transmission
[33] http://ecomputernotes.com/computernetworkingnotes/ communication-networks/data-transmission
[34] https://umuc.equella.ecollege.com/file/ d0edbbfc-0779-4cd5-8203-51719a5ffc2e/1/ CMIS435-1109.zip/Modules/M5-Module_5/popups/ Data.html
[35] http://www.techopedia.com/definition/25705/ communication-protocol
[36] http://www.tcpipguide.com/free/t_ TCPIPOverviewandHistory-3.htm
[37] http://mashable.com/2011/02/03/ipv4-ipv6-guide/
4.3. INTERNET 107
[38] http://www.britannica.com/EBchecked/topic/1473553/ Wi-Fi
[39] http://www.mmfai.org/public/docs/eng/MMF_LTE% 20Brochure.pdf
[40] http://www.mobileburn.com/definition.jsp?term=4G
[41] http://searchmobilecomputing.techtarget.com/ definition/4G
[42] http://bpastudio.csudh.edu/fac/lpress/471/hout/3G.htm
[43] http://www.hp.com/global/us/en/wireless/ wireless-basics.html
[44] http://www.kitchentablecomputers.com/nic.php
[45] http://www.techradar.com/us/reviews/pc-mac/ networking-and-wi-fi/modem-routers
[46] http://www.darron.net/network/secondpage.html
[47] http://whatismyipaddress.com/routers
[48] http://compnetworking.about.com/cs/routers/g/bldef_ router.htm
[49] http://compnetworking.about.com/cs/internetworking/g/ bldef_repeater.htm
[50] http://searchmobilecomputing.techtarget.com/ definition/antenna
[51] http://coursemate.cengage.com/CPReader/View/ 9781133114598/default.aspx?eISBN=9781133114598# da32b353-ffd5-4a88-91a8-c28f124d2211
4.3 Internet
4.3.1 Evolution of the Internet
ARPA1974english
The internet has changed dramatically since its first incar- nation. In 1969 the U.S. department of defense created ARPANET.[1] The original concept of this project was to connect researchers located in different places to be able to communicate and collaborate from far distances. The fear of nuclear attack was very prevalent at this time, so the team also wanted to make a network that could still
operate after a nuclear attack. Therefore creating many different fail safes, and alternative routes for packet send- ing was necessary. As this project grew, more and more people gained access to the internet and began shaping it to what we know today. As we have described before, everyone who uses the internet is called an internet user. For these users to obtain access to the internet, you must go through an ISP (internet service provider.) Side note, while the internet is not owned by any one company or government, it is most assuredly not free. It costs money to build, run, and maintain the servers that bring you the funny cat videos.
map of Internet
Internet 2 is an amalgamation of different leaders in the field of academia, technology, industry, and government that formed together in order to collaborate on pioneer- ing and innovative ideas that help advance education and research. They test new network applications and tech- nologies using high-performance networks. Contrary to popular opinion, Internet 2 is not a gathering of minds who intend to replace the current Internet but congregate to ensure that the future Internet will be capable of oper- ating with today’s engineering. Internet 2 is currently be- ing upgraded to 8.8 terabytes! This will aide in the ability to offer advanced telemedicine and long distance learn- ing opportunities across connected countries through its network.[2]
4.3.2 The World Wide Web
The World Wide Web is different than the Internet. The Internet started out being used more by private industries and people such as scientists, schools, and the govern- ment. The public had not used it for the most part be- cause it was complex and you had to have a computer in order to access it, which not everyone did. In 1989 Tim Berners-Lee came up with the World Wide Web and
108 CHAPTER 4. NETWORKS AND THE INTERNET
Web-browser-openclipart
thought it would be a good way to organize information and take place of the Internet. Although the Internet still stayed around, and still is today, the World Wide Web was a great tool for researches at the time. The World Wide Web is not owned by one single business or per- son, but the webpages are. The Web consists of things such as HTML, URL, and HTTP. HTML stands for Hy- per Text Markup Language and is used for formatting documents on the Web. URL is the Uniform Resource Locator which most of us are familiar with when typ- ing in addresses to websites. And lastly, HTTP is Hy- per Text Transfer Protocol. This is what lets people click on hyperlinks and be redirected to that specific location. The World Wide Web has changed the way schools teach, businesses run, and average people have been able to ac- cess organized information.[3] Pictures and documents are now easier to access and research and recreational websites can now be found in one place.[4]
4.3.3 Using the Internet
Getting Set Up To Use The Internet
Almost every household has access to the internet; there- fore, it is important to know how to have access to the world wide web. There are five basic steps to set up an internet connection which consist of the following:
1. One must connect the hardware. Different hardware and software contain directions in setting up. Use the directions to set up these systems.
2. The internet needs a wireless connection or an Eth- ernet cable before it can go online. Therefore, the computer owner must make this connection.
3. The computer owner must connect to the default IP
Crystal Clear app Internet Connection Tools
address. The IP address usually consists of eight numbers, and it is broken up occasionally by peri- ods.
4. It is the internet’s server’s responsibility to show the computer owner how to actually establish the con- nection. One must then set up a name and password for security purposes.
5. Save the settings, and the internet light will turn green to indicate one is online.[5]
Different Internet Connections
There are many different kinds of internet connections. A few of these connections consist of wireless, broad- band, and dial-up. Wireless is a router or a network that connects to a hot spot. A broadband is connected directly to a broadband modern, and one needs a user name and password to connect. A dial-up is used remotely via a telephone line.[6] Different types of internet connections come with their own pros and cons and it is important to choose one that will work well with your lifestyle and your wallet.
Dial-up Dial-up connection requires a phone line to function. Because of this, people cannot be using the phone and the internet at the same time. When con- necting to the internet via dial-up, the computer tries to
4.3. INTERNET 109
connect through the phone line and causes dial-tones and many numerous sounds to emit from the modem. Dial-up is also the slowest form of internet connection and has a maximum speed of 56 kilobits per second. It is also the most archaic type of internet connection and only about 3% of Americans are still using it.[7][8]
Wi-fi Hotspots Wi-fi hotspots are another form of in- ternet connection in which a wireless access point, such as a router, has a direct connection to the internet and al- lows people to connect wirelessly through the use of wi- fi. Although they aren’t used very much at home, wi-fi hotspots are often used at locations such as restaurants, hotels, and airports. Many restaurants such offer free wi- fi to entice customers, while others have a fee for using their internet.[9]
Fiber-Optic Cable
Broadband over Fiber A new technology called broadband over fiber (BoF) is a direct connection option for internet access. Internet service providers are start- ing to adopt this new technology and sell it for a fee.[10] For example, Verizon’s version of broadband over fiber is called fiber-optic service (FiOS). FiOS, in particular, is able to provide services such as telephone, television, and internet. BoF is advertised on Verizon’s FiOS webpage as a network that, “provides bandwidth to meet today’s dig- ital demands and the possibilities of tomorrow.”[11] This statement is probably used because BoF’s data transfer speeds are much faster than other services. In fact, with fiber-optic cabling, data transfer can travel at the speed of light. One drawback of BoF is that it is very expen- sive. In order to create a fiber-optic network, you must invest a lot of money in constructing an essential infras- tructure. Another negative with broadband over fiber is that the cables are very sensitive. This means that cables can not be installed on telephone poles or underground. Cables must be installed above ground, usually in piping, so that the cables are protected from bending and shift- ing. BoF is practical and efficient for small networks due to less complex construction of infrastructure. This being said, the United States probably won’t have nation wide BoF networks.[12]
Selecting an ISP
There are many different Internet Service Providers, some of the most popular include Comcast, AT&T, Ver- izon, and Time Warner Cable.[13] When you choose an ISP, there are many factors to take into consideration. Some of those factors include price, type of internet con- nection you want, speed, customer support, types of de- vices you use, and cancelation policies.[14]
Fiber Optic Cable
Some internet service providers, such as Verizon and Google, are now starting to offer fiber- optic internet connections. Fiber-optics allows unsurpassed connec- tion speeds, both upload, and download. Fiber-optic in- ternet connections employ Fiber-optic cables that trans- fer large amounts of data through hundreds of stands of glass or plastic which employ an entirely light based, op- tical technology. The technology has existed for many years, but many may have begun to hear that it has be- come more commonly available over the recent years. After implementing fiber-optics in commercial internet service packages, Internet Service Providers are now able to confidently boast connection speeds exceeding 100gi- gabits per second, speeds that are much more desirable to many households as well as businesses. [15] Fiber op- tic networks are, to no surprise, very expensive. Massive internet service providers such as Comcast, AT&T, and COX may not be ready to spend hundreds of millions, and even billions on city wide fiber- optic networks, thus mak- ing the transition to fiber-optics before the technology a long one. Google alone spent over 80 million dollars to reach 150,000 households with their fiber-optic connec- tions. Only a small handful of cities currently have the luxury of a fiber-optic connection, and it may take some years before the technology is available to a majority of households. [16]
4.3.4 Searching the Internet
Search Sites
Search sites are websites that are specifically created to help search the Internet. Examples would include,
110 CHAPTER 4. NETWORKS AND THE INTERNET
Bing! A popular search site.
“Google,” “Bing,” “Yahoo! Search,” and “Ask.com.” There are also many other not as well known search sites. Search sites generally use a search engine, which is a pro- gram for the retrieval of data from a database or network. A search engine includes a spider, which goes to every page on every Web site that wants to be searchable and reads it. Then there is a program that creates an index from the pages that have been read. Then a program that receives your search request and compares it to the index, then gives you results.[17] Most search sites today are de- signed for keyword searches, which is when you type in keywords describing what you are searching for. A direc- tory search is the other kind of search hat some sites allow and it uses lists of categories instead of a search box.[18] Many search sites will also contain tools that can be used to find information. Many sites try to present their results as clearly as possible. They will also tend to make sugges- tions about things that are similar to what you searched that may help you find what you are looking for.[19]
Google Search
When it comes to search sites, there are a few that almost everyone is familiar with. The common phrase, “Google It,” is an indication that Google has become a household name when it comes to search engines. Google boasts an astounding 1,100,000,000 monthly visitors. With num- bers like that, it is easy to see why Google has become the household name for search engines. However, few are as familiar with some of the other search sites that are available today that provide the same kind of service that Google does. One of these lesser known search sites is Duck Duck Go. One of this sites great features is that it does not share any of its clients data with other search sites which makes for less advertisement pop ups and stronger privacy for the user. This has appealed to more and more users after information surfaced that the U.S.
has direct access to the servers of major search engine companies allowing the U.S. government to gain knowl- edge of exactly what people are searching for. This infor- mation inspired the founder of Duck Duck Go, Gabriel Weinberg, to start this company in 2008, to ensure the rights and privacy of its users. Gabriel Weinberg was quoted as saying, “Search data is arguably the most per- sonal data people are entering into anything. You’re typ- ing in your problems, your desires. It’s not the same as things you post publicly on social networks.” Duck Duck Go has is a great alternative to larger search engines and for users who really value their privacy.[20]
DuckDuckGo zero-click info
Search Strategies
Icon search updates 96x96
Searching for particular information can be fun but also can be very frustrating. Here are few different search strategies which can help to find the information needed, such as simple, complex, phrase, natural language and de- fault Boolean Logic searching. Simple searching is the easiest method of using a search tool.[21] The user can type one or more key words (spelling counts) in the search box then click on the search button. Complex searching
4.3. INTERNET 111
is using Boolean Logic[22] to improve search efficiency. The words such as AND, OR, and NOT are entered be- tween keywords to refine the search. In phrase search- ing, a user should enclose quotation marks when search- ing for specific phrase. Most search engines like Google, Bing, and such recognize this protocol. Natural Language searching is allowing a user to type a sentence or question just the way he/she might like and the search tool will try to determine key words and locate pages based on these words. Default Boolean Logic searching allows a user to type key words as in simple search. Search tool, depends on its default, will use OR or NOT. If a user is tired of typing, she/he can click on the microphone icon in the Google app or Chrome’s search box to search by voice.[23]
4.3.5 Beyond Browsing and Email
Instant Messaging and Text Messaging
You send text messages with a cell phone such as this one, though SMS has been on the decline
Communication is quite possibly the most important tool that humans can hone. While e-mails are a fast and environmentally-friendly method of Internet-based com- munication, there are two types of messaging that are faster and easier. These two types of messaging are: in- stant messaging and text messaging. Instant messaging, also referred to as chat, allows you to type out a message on your keyboard and then press 'enter' to have it sent im- mediately to the other party. Unlike emails, where you have to wait for the other person to be around at their computer to read the message, and THAT is assuming
your email didn't get lost because of a faulty spam filter, IM’s create a connection that is almost as good as being in the same room with the friend. To instant message a friend, you typically both need the same IM client, of which there are many free varieties such as AIM, MSN, YIM, and Skype. Text messaging, which is also called SMS (Short Message Service), used to be the most popular means of speedy communication though it has been on the decline.[24] Text messaging allows users to send fast and typically short notes with their cellular phones. The major downside of text messaging is how many cellphone companies charge a ton for your texts while instant messaging is free (plus the cost of the internet for your computer or phone, of course). Also text messages, like emails, need to be waited for and can sometimes not make it to the right place without a glitch whereas instant messengers tend to have a better track record.
Online Shopping: Amazon and More
Amazon Box
Online shopping is so convenient for many who are on the go. There are no hours of operation to abide by, no lines to wait in, and consumers do not even have to leave the comfort of their own home to get what they want. There are some downsides of online shopping, such as not being able to try on clothes to see if it is the right size. The largest online retailer is Amazon.com. Shop- pers seems to go-to website for all online shopping needs. The retailer started as an online book store, but now offers purses, electronics, movies, music, and even sports equip- ment, just to name a few. Sellers can create accounts fairly easy and try to sell their goods. Buyers need to be the cautious ones and look into the reviews to see who they are buying from. One advantage of shopping with Amazon is that they have an A-Z guarantee that helps the buyers resolve conflict with the sellers.[25] Amazon expanded their services to include areas such as Ama- zon Art, Amazon Instant Video, Amazon Prime, Ama- zon Local, Amazon Wireless, Amazon Fresh, and Ama- pedia. One controversy that comes up with Amazon.com,
112 CHAPTER 4. NETWORKS AND THE INTERNET
as well as online shopping, is that consumers are not pay- ing their true county sales tax. Instead they are paying the sales tax that Amazon collects.To challenge Amazon, Google has decided to start to expand its e-commerce role. Google wants to compete with amazon and their ability to sell merchandise around the world. Google is allowing consumers to search for something and Google would tell them if there is somewhere nearby to purchase that item. It is a great retaliation against amazon. They would charge $95 a year or $10 a month, or pay $4.99 per order. Google is also offering overnight shipping.[26]
Online Banking
Online Banking has become increasingly popular in this tech-savvy generation. Most banks now allow transac- tions to be done online through their website or through phone apps. While some people question the security of making transactions online, the biggest advantage is that online banking is very convenient. People can set up ac- counts through a few simple steps, can make transactions between different accounts they have, transfer money, make payments on credit cards, and more. Some only- online banks have formed and are gaining popularity be- cause they have less fees and thus are cheaper. Some banks try to offer deals with higher yield to make online banking more appealing. Lastly, it is handy to have 24/7 access to speedy transactions, which traditional banks cannot offer. Online banking did have a shaky start, but now it is growing quickly.[27] According the Bankrate website, 65% of consumers use online banking.
4.4 Pros and Cons
Money Online Logo
In the last few years, online banking has become increas- ingly mainstream. For some, it is the new norm, as having to make daily or weekly trips to the bank can be both un- pleasant and inefficient. For the most part, online bank- ing is advantageous -- and though the pros certainly out- weigh the cons, no system is flawless. First, an obvious pro is convenience. An ability to pay the majority of bills online, whether it is through a checking, savings, money market account, etc. is something that is necessary in our fast-paced, demanding world. Many
creditors offer an automatic plans to ensure customers are not charged penalties if they forget to pay a bill. In addi- tion, there is also mobile capability. Most banks feature mobile-friendly websites that allow customers to bank on- the-go. The applications banks offer are typically free, and are being implemented with new features all the time in an effort to expand availability to smartphone users. Lastly, the ease of navigation is comparable to that of any other website. To prevent or assist with issues, most banks have 24-hour live customer service or e-mail cus- tomer service. The most significant con to online banking is security, with computer hacking and identity theft being such widespread problems. Despite the best security measures, there is always risk that someone, somewhere will be able to gain access to your bank account and/or sensitive in- formation. Another concern is transaction issues. There are some aspects of banking that should be done behind a teller’s desk instead of a monitor or screen. Deposit- ing cash, certain types of international deals, and similar difficulties may be challenging to address or solve via the internet. Another, less threatening issue for those who frequently make impulse purchases or budget poorly is a lack of money management, as instant access to a balance can precipitate irresponsibility. [28]
Social Media
Voip HowItWorks 0203v2
Besides texting, instant messaging, and online shopping, there are hundreds of other things you can use the Web for. One of the main things people use it for today is so- cial media. Things from Facebook and Twitter to email
4.4. PROS AND CONS 113
Skype-icon
Snapchat Logo
and online newspapers are all forms of social media, or sites used to share information to groups of people over the Internet. The problem with the huge explosion that has been the beginning of the social media era is that it is becoming increasingly difficult to believe information posted online. The Internet has evolved so much that now we are able to even perform video and telephone functions through it. Sites like Skype are taking advantage of this technology. According to the FCC (Federal Communica- tions Commision) the technology used by Skype, Vonage, and other similar Companies is called VoIP. They define this technology as one “that allows you to make voice calls using a broadband Internet connection instead of a reg- ular (or analog) phone line”.[29] Essentially, performing telephone functions through the Internet is VoIP. Social Media has seemingly encompassed the younger genera-
tions of today; while it has been slower to catch on with the older generations, it is something that has been in- creasing over time.Skype had recently acquired a newer company called Qik and plans on dominating the new way for people to communicate using mobile video messag- ing. Skype Qik is supposed to be very simple, and it is exactly like texting but all video. A person can send a Qik video to anyone and they do not even have to have the app. These conversations are asynchronous and Skype Qik is a great idea for communication since things like facetime have been a big trend. The thing with facetime though is that someone has to answer the phone and both people need to use it at the same time; with Skype Qik people have the ability to have that type of video interac- tion but at no specific time. Skype Qik was developed by Microsoft,a dn is available on a PC or Mac, and for the iPhone, Android, or Windows phone.[30]
Another popular social media app is Snapchat. This app allows people to send pictures, videos, and texts, just like other apps, but the catch is that once the pic- ture/video/text is opened, it disappears after the set amount of time and cannot be see again. Snapchat has many features which make Snapchat photos and videos more fun and interesting than on other apps. Such fea- tures include filters, different text fonts, and the ability to draw on the pictures/videos with different colors. In addition to these original features, Snapchat has added a feature called “My Story” where users can create a chain or video of multiple pictures and videos combined. This story is not sent to one specific person, rather any of the user’s friends can see it; the set time in this feature deter- mines how long the picture shows in the “slide show” and the story is available for only twenty-four hours. The lat- est feature is “geolocation” which can give you the time, weather, miles per hour, or other site-specific filters based on your location.[31]
RSS and Podcasts
Almost every popular website will have this RSS logo.
114 CHAPTER 4. NETWORKS AND THE INTERNET
First invented by Netscape, Really Simple Syndication (RSS) is an online tool designed to quickly distribute new articles and other content when it is changed or added to. The reason for its invention was because it was an easy way for Netscape to share headlines and stories from other sites, and automatically add it to their own. To help people keep updated on their favorite websites, RSS uses an XML code that constantly scans a website and then broadcasts those updates to all the subscribers through its RSS feed. Subscribing to an RSS feed—usually for free—is fairly simple, as all one has to do is sign up with a feed aggregator, which will store all of one’s RSS sub- scriptions, and then click the subscribe link on the asso- ciated Web page. Finally, its feed content will automat- ically be added to their browser feed list, similar to the Favorites Feed list in Internet Explorer. For better ac- cessibility for today’s evolving generation, RSS feeds can also be delivered to mobile phones and maybe even di- rectly to televisions sometime in the future. [32]
Another simple way to gather useful information from the Web is a Podcast, which is simply a recorded audio or video file that can be downloaded from the Web. De- rived from the combination of the words “broadcasting” and “iPod,” podcasting is a form of audio broadcasting, which can be listened on one’s iPod. However, this is not a limitation since podcasts also be listened to on comput- ers via the Windows Media Player or iTunes, or smart- phones. The difference between podcasting and simply downloading and listening to music online is the fact that with podcasting, files come to you through syndication, instead of the other way around. Much like the blogs and websites mentioned previously, podcasts can be sub- scribed to in order to download new podcasts whenever they become available. [33]
Online Testing
Online testing is becoming a new alternative for taking tests in this technology-based world that we live in nowa- days. Online tests can be used for both objective tests, like multiple choice or true/false, or performance-based tests, like a concussion test. The state of Washington started using online testing in the spring of 2010 to ad- minister tests of math and science for grades 3-8.[34] This testing format creates more options for a teacher’s cur- riculum. Usually, one or two days are necessary to com- plete a test in class, but with an online test, no class days are taken up. This allows for the teacher to either go more in-depth on topics, allow for more Q&A during class room time to make sure his or her students under- stand the material, more time to prepare for an online test day, or it allows for more material to be covered. All of these options are great for the education system be- cause students gain more knowledge from their tuition. One problem with online testing is security. How would a teacher know if the right student is taking the test, if the student is looking online or using another person to help
them? To overcome this obstacle, technology companies are creating devices like the Securexam Remote Proctor system that takes a 360-degree image of the room and uploads it to a server where the teacher of the class can view it. All in all, online testing is the wave of the future for the education system with testing.
Blogs, Wikis, and Other Types of Online Writing
Wikipedia logo
A blog is a Web page that contains short, frequent up- dated entries in chronological order, typically as a means of expression or communication. Blogs can be written by anyone, including ordinary people, celebrities, or even experts of certain fields. As blogs become more and more popular, commercial advertising begins to be com- monly seen on more of the popular blogs. Some of the most popular blogs are websites that offer information or helpful tips to their readers. For example, as of Octo- ber 2014, the top three most popular blogs are: Huff- ington Post, TMZ, Business insider.[35] Another form of online writing, most often used for education purposes, is the wiki. Wikis are a way of creating and editing col- laborative Web pages quickly and easily. Unlike a blog, wikis are meant to be edited by anyone, not just the owner of the typed information. One of the largest wikis is Wikipedia(Wikibooks is an example of a wiki too). While wikis are helpful and collaborative, erroneous in- formation can be added intentionally. As a result, it is recommended to be careful when fully trusting a wiki page. Another type of online writing is an e-portfolio. An electronic portfolio is a collection of an individual’s work accessible through a website. Today. e-portfolios are commonly linked to student-related information, such as resumes, papers, or projects.
4.4. PROS AND CONS 115
2008 Intel Developer Forum Taiwan Day2 MID Keynote Online Game Demonstration
Online Gaming
Everywhere you look, young people are using smart- phones, notebook computers, iPads, etc. Often, they are not just using these devices for school research, home- work, or studying. Young people can be seen playing games on computing devices as young as 3 years old. On- line gaming is a rapid habit that is starting from a very young age. Often, the habit carries into the young adult years for many individuals. Nowadays, there are whole web sites whose sole purpose is hosting games that can be played online. Online games can be played alone or with other individuals who are also online. The games that are designed to be played by multiple players are called online multiplayer games. Some examples of online mul- tiplayer games are Doom, EverQuest, Final Fantasy, City of Heroes, and World of Warcraft. Also, gaming devices, such as, PlayStation 3, Xbox 360, and Wii, are deigned to be Internet-enabled so they can be connected to the Internet to play with other players. Online gaming has also been associated with Internet addiction. An arti- cle about online gaming addiction in The Kernel, states that often individuals are playing online games 12 hours a day. The article explains that individuals that develop online gaming addiction lose jobs and loved ones, have withdrawal symptoms, and develop migraines and back problems. The article states that it is a very real problem and will potentially continue to grow in the population as the Internet becomes more readily available to more and more people.[36]
Video Chatting
Video calls have played a major part in science fiction for decades. They were a major part of the film 2001: A Space Odyssey, and many other films and TV shows of that genre. Now, video chatting capabilities are found as standard on most desktops, and mobile devices. On of the most well known programs, and the program that pioneered video chatting, is Microsoft’s Skype. In re-
Facetime Logo
cent years, Skype has been joined by Apple’s Facetime, and a video chat program embedded in Google Hang- outs. Skype is compatible with Microsoft, Mac, and Linux computers, and there is and app for mobile devices. Facetime however, is only available on Apple devices, al- though the company has promised to make it compatible with other devices at some point. Google Hangouts, be- ing a part of Google online app suite, is available as long as the user is able to access the Internet. There are other free source programs, but these three are the most com- mon and the most trusted by security programs. Video chatting was touted as a futuristic ideal, but in recent years, this has not held true. Video chatting use has de- cline in favor of texting and online testing apps. These may be the future as opposed to video chatting. [37]
4.4.1 Censorship and Privacy
Bypassing internet censorship
Censorship
Censorship is the control of the information distributed within a society and has been a sense of dictatorships throughout time. It’s the suppression of offensive expres- sions that are used for when people want to provoke their
116 CHAPTER 4. NETWORKS AND THE INTERNET
personal political or values to another group. Typically now censorship is filtered by the government to control the information that is given to the public. Censorship by the government is typically unconstitutional because of the freedom of speech and is highly fought against in the First Amendment. Different countries are now censor- ing their countries privacy information for their countries safely and they occasionally stop the information coming in and out of the country. On another note, when individ- uals are on strike or boycott an event they are protected by the First Amendment which can be dangerous but they are still known to be protected. Some private censorship campaigns are best countered by groups and individuals speaking out and organizing in defense of the threatened expression.[38][39]
TOR logo.
Fighting Internet Censorship Internet users who live in countries where the government tries to block or in- hibit Internet use can still sometimes access material that is supposed to be forbidden. One way to do this is via a proxy, where Internet connectivity is routed through an- other server. If, for example, Facebook is blocked, an In- ternet user can use connect to a proy server that, in turn, connects to Facebook, giving the user access to Face- book without directly connecting to it.[40] There is also a browser dedicated specifically to Internet activity known as TOR for “The Onion Router”, which proves multiple layers of encryption, like layers of an onion, as the data
people are submitting or accessing is routed through mul- tiple different 'nodes’ and encrypted in between each one. The idea is that this will provide total anonymity, so that people cannot be tied to their access of or posts on certain websites. While it is sometimes given a negative conno- tation as a tool only for criminals, TOR is actually incred- ibly useful for people in countries whose governments are trying to oppress their citizens’ freedoms of speech and press.[41] In short, while it is not easy or necessarily safe for people in these nations to access everything they should be able to access on the Internet, it is possible, and there are some means of circumventing government censorship of the Internet, which is not always holeproof.
Web Browsing Privacy
Knowledge of internet privacy is vital
Privacy is of great importance to all users of the In- ternet. According to Wikipedia, internet privacy in- volves the right or mandate of personal privacy concern- ing the sorting, repurposing, provision to third-parties, and displaying of information pertaining to oneself via the Internet.[42] This has been a subject of concern for decades. For example, one article that addresses the po- tential implications of privacy and computer dates back to 1965.[43] While it is certain that privacy can be infringed, a simple awareness of how exactly certain processes, like using a search engine, interact with a user can be help deal with some of these concerns. When one uses a search engine, such as Google, small files known as cookies are created to help identify pref- erences for the user. This enables a more accurate and quicker response when beginning a new session. To put this into context, cookies can help retrieve information like what was in a shopping cart for a previous session. However, third-party cookies can be more of an issue to some. Companies use these cookies to target adver-
4.4. PROS AND CONS 117
tisements towards users depending on their browsing pat- terns. Using the Internet Options in Internet Explorer (for Windows) can help one decide what types of cookies can be allowed as well as delete all cookies off the hard drive. A more serious threat to internet privacy is spyware, which refers to any software that is installed without knowledge of the user that obtains information about that user through an Internet connection. The degree to which these programs can cause harm range from simple an- noyances (e.g. setting a homepage to something else) to full-scale threats on system integrity (e.g. rewriting the Windows registry to restrict the user from changing the homepage back to its original state). Adware, while related to spyware, is less harmful. Ad- ware is usually installed alongside other software, and this leads to advertisements that appear on-screen. This can be installed without prior knowledge during the instal- lation of another program by not reading the licensing agreements that came with the program. Therefore it is important to read carefully the agreement to ensure un- wanted software is kept away from the computer.
Proxy BobAlice
Ask Bob what the current time is
What is the current time
The time is 7pm
Bob says the time is 7pm
A simple diagram of how proxies work
In order to prevent personal information from being com- promised and to keep your computer and internet run- ning smoothly there are several precautions that should be taken to ensure that your web browsing experience is a safe and private one. Perhaps the easiest method to do this is by activating private browsing on your inter- net browser application. Once turned on the browser can not save any files or data to your local machine, includ- ing cookies, cache, and history. If you are using regu- lar browsing, these files can still be deleted through your browser or another application. Disposing of these files ensures that online sites cannot track your activity on the web. You can also use programs to ensure that you are not being targeted for certain advertisements because of your browsing history, a common occurrence in the mod- ern marketing age. To be very anonymous on the internet, a Tor network can be setup that encrypts the data you are sending so that your IP address is not compromised.[44] Another similar method is proxies, which are intermedi-
ates that receive and deliver information requested. This keeps your personal computer information private as the server is technically the one making the request, not you.[45]
E-mail Privacy
Gmail Controversy
It is extremely important to always make sure that any important or confidential information being shared over the Internet is being done in a private and confidential way. One of the unfortunate downfalls to everything be- ing done electronically today is that we lose a sense of privacy. Things are much easier to attain on the Inter- net, and sadly there are hackers out there who spend their time trying to break into and gain access to this confi- dential information. If you are going to send important information electronically, it is necessary that you send it in an encrypted message. Encrypted messages make it so that others cannot hack into your e-mails and read what you are saying. One of the more recent controversies with privacy in e-mailing has to do with Google mail. Google has come out saying that they should be able to read the information sent by any of its Gmail users. People find is- sue with this because they are gaining personal and confi- dential information that individuals do not want out there. The purpose of sending a specific email to a specific indi- vidual is so that it can be done in privacy, with the hopes that only that recipient will receive it. However, today this is unfortunately not the case, and if you are going to send mail electronically, one needs to proceed with caution.[46]
4.4.2 Review
Review Definitions
Mobile Phone:A phone such as a cellular, or satellite phone that uses a wireless network. Cell Phone:A mobile phone that communicates via a cel- lular network. Satellite Phone:A mobile phone that communicates via satellite technology. Dual-Mode Phone:A mobile phone that can be used with more than one communications network, such as with both a cellular and Wi-Fi network.
118 CHAPTER 4. NETWORKS AND THE INTERNET
Global Position System (GPS:A system that uses satel- lites and a receiver to determine the exact geographic lo- cation of the receiver. Videoconferencing:The use of computers, video cam- eras, microphones, and networking technologies to con- duct face-to-face meetings over a network. Telecommuting:The use of computers and networking technology to enable an individual to work from a remote location. Telesurgery:A form of robot-assisted surgery in which the doctor’s physical location is different from the pa- tient’s physical location and the doctor controls the robot remotely over the Internet or another network. Telemedicine:The use of networking technology to pro- vide medical information and services. Wireless Network:A network in which computers and other devices are connected to the network without phys- ical cables; data is typically sent via radio waves. Star Network:A network that uses a host device con- nected directly to several other devices. Bus Network:A network consistent of a central cable to which all network devices are attached. Mesh Network:A network in which there are multiple connections between the devices on the network so that messages can take any of several possible paths. Personal Area Networks (PANs):A network that con- nects an individuals’s personal devices that are located close together. Local Area Networks (LANs):A network that connects devices located in a small geographical area, such as within a building. Wide Area Networks (WANs):A network that connects devices located in a large geographical area. Intranet:A private network that is set up similar to the Internet and is accessed via a Web browser. Extranet:An intranet that is at least partially accessible to authorized outsiders. Virtual Private Networks (VPNs):A private, secure path over the Internet that provides authorized users a se- cure means of accessing a private network via the Inter- net. Analog Signal:A type of signal where the data is repre- sented by continuous waves. Digital Signal:A type of signal where the data is repre- sented by 0s and 1s. Serial Transmission:A type of data transmission in which the bits in a byte travel down the same path one after the other. Parallel Transmission:A type of data transmission in which bytes of data are transmitted at one time, with the bits in each byte taking a separate path.
Twisted-Pair Cable:A networking cable consisting of wire strands twisted in sets of two and bound into a cable. Coaxial Cable:A networking cable consisting of a cen- ter wire inside a grounded, cylindrical shield, capable of sending data at high speeds. Fiber Optic:A networking cable that utilizes hundreds of thin transparent fibers over which lasers transmit data as light. Cellular Radio:A form of broadcast radio designed for use with cellular telephones that broadcasts using anten- nas located inside honeycomb-shaped cells. Microwave Station:An earth-based device that sends and receives high-frequency, high-speed radio signals. Communications Satellite:An earth-orbiting device that relays communications signals over long distances Infrared (IR) Transmissions:A wireless networking medium that sends data as infrared light waves. TCP/IP:A networking protocol that uses packet switch- ing to facilitate the transmission of messages; the protocol used with th Internet. Ethernet:A widely used wired LAN networking stan- dard. Wi-Fi:A widely used networking standard for medium- range wireless networks. WiMax:An emerging wireless networking standard that is faster and has a greater range than Wi-Fi. Wi-Fi Direct:A standard for connecting Wi-Fi devices directly, without using a router or an access point Bluetooth:A networking standard for very short-ranged wireless connections; the devices are automatically con- nected once they get within the allowable range. Ultra Wideband (UWB):A networking standard for very short-range wireless connections among multimedia devices. WirelessHD:An emerging wireless networking specifi- cation designed for connecting home consumer devices. Wireless USB:A wireless version of USB designed to connect peripheral devices. TransferJet:A networking standard for very short=range wireless connections between devices; devices need to touch in order to communicate. Network Adapter:A network interface, such as an ex- pansion card or external network adapter. Network Interface Card (NIC):An expansion card through which a computer can connect to a network. Modem:A device that enables a computer to communi- cate over analog networking media, such as connecting to the Internet via telephone lines. Switch:A device used to connect multiple devices on a single (typically wired) network; forwards packets to only
4.4. PROS AND CONS 119
the intended recipient. Router:A device that connects multiple networks to- gether; routes packets to their next location in order to efficiently reach their destination. Wireless Access Point (WAP):A device on a wireless network that connects wireless devices to that network. Wireless Router:A router with a built-in wireless access point; most often used to connect wireless devices to a network and an Internet connection and often contains a built-in switch. Bridge:A device used to bridge or connect two LANs; most often used to connect wired devices wirelessly to a network. Repeater:A device on a network that amplifies signals. Range Extenders:A repeater for a wireless network. Antennas:A device used for receiving or sending radio signals; often used to increase the range of a network.
Review Questions
4.4.3 References
[1] wiki: ARPANET
[2] http://www.internet2.edu
[3] http://webfoundation.org/about/vision/ history-of-the-web/
[4] http://www.nethistory.info/History%20of%20the% 20Internet/web.html
[5] http://www.wikihow.com/ Set-Up-an-Internet-Connection
[6] http://windows.microsoft.com/en-us/windows-vista/ what-are-the-different-internet-connection-methods
[7] http://www.cnet.com/news/ 3-percent-of-american-adults-still-cling-to-dial-up-internet/
[8] http://www.packetworks.net/blog/ internet-connection-types
[9] http://en.wikipedia.org/wiki/Hotspot_(Wi-Fi)
[10] Understanding Computers 14th Ed. by Deborah Morley & Charles Parker
[11] http://www.verizon.com/home/fios/
[12] http://www.wisegeek.com/ what-are-the-pros-and-cons-of-fiber-optic-broadband. htm
[13] http://www.practicalecommerce.com/articles/ 3225-20-Top-Internet-Service-Providers
[14] http://www.easyt1.net/blog/ 10-things-to-consider-when-choosing-an-internet-service-provider
[15] http://arstechnica.com/business/2014/04/ one-big-reason-we-lack-internet-competition-starting-an-isp-is-really-hard/
[16] http://en.wikipedia.org/wiki/Fiber-optic_ communication
[17] http://www.webopedia.com/TERM/S/search_engine. html
[18] http://www.webopedia.com/TERM/K/keyword_search. html
[19] http://webaim.org/techniques/sitetools/
[20] http://www.dailymail.co.uk/news/article-2360059/ DuckDuckGo-little-known-search-engine-refuses-store-data-users-doubles-web-traffic-amid-NSA-tapping-scandal. html
[21] https://www.bcps.org/offices/lis/models/tips/ searchstrategies.html
[22] http://www.webopedia.com/TERM/B/Boolean_logic. html
[23] https://support.google.com/websearch/answer/134479? hl=en
[24] http://blog.brosix.com/ why-instant-messaging-is-now-more-popular-than-sms/
[25] http://www.ioba.org/newsletter/archive/8%284%29/ toolbox2.php
[26] http://www.dailyherald.com/article/20141014/business/ 141019213/
[27] http://www.bankrate.com/finance/checking/ pros-cons-online-checking-accounts-1.aspx
[28] http://www.nasdaq.com/article/ the-pros-and-cons-of-online-banking-cm386361
[29] http://transition.fcc.gov/voip/
[30] http://www.theverge.com/2014/10/14/6973625/ skype-qik-video-messaging-features
[31] http://mashable.com/2014/08/13/ snapchat-tips-and-tricks/
[32] http://www.wisegeek.com/what-is-rss.htm
[33] http://www.entrepreneurs-journey.com/230/ what-is-a-podcast/
[34] https://www.k12.wa.us/Assessment/StateTesting/ OnlineTesting.aspx
[35] http://www.ebizmba.com/articles/blogs
[36] http://theweek.com/article/index/255964/ the-psychology-of-video-game-addiction
[37] http://www.howtogeek.com/186267/ the-3-easiest-ways-to-video-chat-online-or-on-the-go/ #
[38] http://gilc.org/speech/osistudy/censorship/
[39] https://www.aclu.org/free-speech/censorship
120 CHAPTER 4. NETWORKS AND THE INTERNET
[40] http://www.rfa.org/about/help/web_access.html
[41] https://www.torproject.org/
[42] https://en.wikipedia.org/wiki/Internet_privacy
[43] http://www.multicians.org/fjcc6.html
[44] http://www.cnet.com/how-to/ five-smart-ways-to-keep-your-browsing-private/
[45] https://en.wikipedia.org/wiki/Proxy_server
[46] http://www.foxnews.com/tech/2013/09/05/ google-seeks-to-dismiss-gmail-privacy-lawsuit-says-it-has-right-to-scan/
4.5 Security
4.5.1 Unauthorized Access and Control Systems
Encryption - decryption
Firewall is a type of security system that creates a wall that checks all incoming and outgoing messages to ensure only authorized traffic goes through. There are many different forms of this application such as Norton[1] and Windows Security Essentials.[2] Another way to protect your infor- mation is encryption. Encryption basically scrambles and makes any message sent unreadable to anyone who does not have a key. The key is then used to decrypt the scram- bled message into the original format. Whenever you go to a website that has an S after the HTTP that means it is a secure web page. Meaning the entire web page is encrypted, so people hacking to your web browser can- not get you credit card number or SSN. One question that arises is, can't you just make every website a secure web page? The simple answer is money, a site owner needs to pay someone to encrypt the site. Then to send the data takes up more bandwidth, and slows down traffic in gen- eral. Another form of protection is a VPN (virtual pri- vate network). A VPN creates a link between the user and some other destination. In order to access the VPN you will need a username and password, in order to keep it more secure and to block out hackers. Firewalls can work in a number of ways, but a cou- ple types of firewalls are more widely used over others. The two most common firewalls are packet-filtering and proxy. A packet-filter simply examines each packet to determine whether it is safe or not. After examining a packet, the filter will either allow in or block out the packet depending on if it’s safe or not. Packet-filters are
Firewall
common among routers, switches, wireless access points, etc. A disadvantage of using a packet-filter firewall is that some packets that are safe may be blocked by accident. This means that it is possible that parts of information could be missing due to a packet being blocked.[3] The other common firewall, called a proxy firewall, is often referred to as the most secure type of firewall. Proxy firewalls are very secure due to the fact that it limits, or totally excludes, direct connections. Direct connections are limited by packets being sent from one computer to the proxy, and then mirrored over to the computer on the receiving end. A disadvantage of a proxy firewall is that it can slow down the transfer speed of packets. Although decrease in speed or functionality is a disadvantage, it is important to remember key advantages. While using a proxy firewall it is difficult for someone to figure out the location of where packets were sent from.[4]
Firewall
The Internet was created as an open system for the free exchange of information. Due to the openness of an ide- ology the Internet provides to “bad guys” the significantly greater opportunities for the penetration into information systems. Firewalls make it possible to filter incoming and outgoing traffic that flows through your system. The Fire- wall uses one or more sets of rules to check the network packets as they enter or exit through a network connec- tion, it either allows the traffic through or blocks it. The Firewall could be applied for protection a single host as well as to protect the entire network. A computer Fire- wall may be built-in into the Operation System or in- stalled separately. The network Firewalls are the more complicated systems, combined hardware and software. These days, there is no single, the universally accepted classification of firewalls. But according to the methods
4.5. SECURITY 121
of deploying it is possible to identify three following types of them. Filtering routers are the routers or a servers running on a program configured to filter incoming and outgoing packets. The Packet filtering is carried out on the basis of information contained in TCP- and IP-packet headers. Firewalls based on Session layer gateways. This class of routers is a repeater TCP-connection. Gateway receives a request from authorized client for specific ser- vices and after validation of the requested session estab- lishes a connection to the destination. Firewalls based on Application layer gateways. In order to protect a num- ber of vulnerabilities inherent filtering routers, firewalls should be used by applications to filter connections with services such as Telnet and FTP. This application is called proxy-service. This gateway eliminates the direct interac- tion between the client and authorized external host. The gateway filters all incoming and outgoing packets at the application layer. Application Layer Gateways are good for protection; since the interaction with the outside world is realized through a small number of authorized appli- cations, fully control all incoming and outgoing traffic. Note that application-level gateways require a separate application for each network service.These categories can be considered as the basic components of real firewalls. However, these components reflect the key features that distinguish firewalls from each other.[5]
Retinal Scanner
Biometric Access Systems identify an individual based on their fingerprint, iris, or facial features or other unique physiological characteristic. Keystroke Dynamics recog- nize an individual’s personal typing pattern to authenti- cate the user as s/he types a username or password. Bio- metric readers allow access based on the persons physical characteristics. Fingerprint readers and retinal scanners isolate an unchangeable property in an individual in order to identify them and offer high security based on these measures. They are typically used to control access to high risk facilities such as government property, prisons, and corporate headquarters. Fingerprint scanners have
also been equipped into laptops in order to offer a higher standard of protection in securing personal files. In the same way, a person can download face recognition soft- ware onto their laptop as well. Because biometrics are entirely unique to the user, they are extremely accurate. In the same way no two people will have the same fin- gerprint, a persons facial features and iris’ are as equally unique. In fact, the odds of another person having the same features as another is about 1 in 10^78 power.[6]
PassWord Strength
Identification Systems are a type of Access Control Sys- tem that reassures whoever wants to access your system has authorization. Along with this, Authentication Sys- tems makes sure the person is who they say they are. Possessed Knowledge Access Systems use passwords us- ing information only the user should know. Downsides to this system would be the ability to forget this informa- tion or for it to be found out by someone who should not know. Cognitive Authentication Systems require users to think of their answers to certain personal questions such as their first pet, where they were born, where they have been on vacation, etc. The disadvantages to this system are the same as Possessed Knowledge Access Systems; with a lapse of time a person is more likely to forget their answer to a security question, especially if it had multiple answers. Lastly, Possessed Object Access Systems are a way to identify you with a physical object such as a key- card or badge. Access Control Systems link up to differ- ent types of readers that have the ability to hold data and retrieve it when needed. Some may even have function buttons that let them collect different data used for tim- ing and attendance purposes. Identification Systems are a great tool to ensure the safety and privacy of users and are useful for everyday computers and accounts, business accounts, and much more.[7]
Many WI-FI connections are unfortunately left unse- cured. This allows for any individual with a WI-FI compatible device to potentially piggy back the network. Once an individual is connected to a network, most de- vices connected to that network become available for a skilled hacker to view. This leaves an opening for many possible risks, especially if that network has a high traffic of sensitive information or data.[8] Some war driving soft- ware exists which allows a user, usually with a portable device, to identify many unsecured networks in a short amount of time. This gives a hacker to identify a large
122 CHAPTER 4. NETWORKS AND THE INTERNET
Wireless Connection
number of potential targets. Cyber-Crime has become increasingly prevalent over the years. Hackers are notori- ous for the various crimes they commit. Using malicious software, a skilled hacker is capable of stealing credit card numbers, bank account numbers, and other personal in- formation, some of which make it possible for them to even steal identities. Using a program such as a keylog- ger, a hacker can monitor keystrokes without the individ- ual knowing, allowing them to acquire sensitive informa- tion such as a credit card number, social security number, bank account, or password. A skilled hacker with an un- derstanding of web design can create a phishing website and acquire account information from unsuspecting web- site visitors.[9]
Public Hotspot Safety
Portugal Airport offering a public hotspot
Public hotspots are public networks, usually found within buildings such as restaurants, airports, and hospitals that allow a free or fee-based wi-fi connection to nearby users.
Because these hotspots are public, it is beneficial to take certain precautionary measures when using them. Some of these safety measure include, disabling your computer automatic wi-fi connection feature. Many modern com- puters will automatically connect to any available wi-fi networks and it is important to be aware of this. Also, using a firewall can protect connections from working in the opposite direction. Instead of your computer connect- ing to the wi-fi, there is a chance that other softwares or devices that are perhaps malicious will try to access your computer through the network. Also, you should avoid viewing or inputting personal information while using a public hotspot. Avoid online shopping which requires a credit card as well as using passwords which can link to sensitive accounts. If you are viewing and inputting per- sonal information then try using a virtual private network through the public hotspot which will avoid others from accessing your data. Other precautions include turning off file sharing, using antivirus software, and watching to see if others are trying to look at your computer screen within the public area.[10]
4.5.2 Computer Sabotage
Malware
Malware is a term for unwanted software that gets in- stalled on a user’s computer and performs malicious tasks. It can be as simple as pop-up windows containing adver- tising, otherwise known as Adware, or it can cause signif- icant damage in the form of a Virus. A Virus is a program that can replicate itself and spread to other computers wreaking havoc along the way. There are many differ- ent types of computer viruses that can cause all different kinds of damage to a computer. Another form of Mal- ware is Spyware. Spyware can track a computer user’s web browsing habits and transmit that information to ad- vertisers without the user’s knowledge. Unfortunately, without adequate protection, it is rather easy for a user to inadvertently allow malware installation. It can be as simple as clicking the wrong box in pop-up window on a website. Protection from malware is avail- able through various security software programs. Some are even available for free download, Malwarebytes. [11] Often times, if a computer is already infected, it can block anti-malware apps. One of the benefits of Malwarebytes is that it can be installed even a PC already has malicious programs on it.
Botnets and Computer Viruses
A botnet is a large group of computers that have been taken over; botnets are a serious threat to computer users because of their devious ways of taking over computers. At the time, computer owners did not know their com- puters were being altered. Botnets are commonly used
4.5. SECURITY 123
Protect Your Computer
for DDoS attacks, click-fraud, phishing campaigns, key logging,and host malicious web sites. There are warn- ing signs a computer user should be aware of if he or she’s computer is apart of a botnet. For example, the computer will be extremely slow, one will receive emails accusing he or she of spam, and the computer user will have email messages in his or her’s outbox that was never sent.[12] Also, a malware is any type of deleterious soft- ware. A computer virus is a common type of malware that ruins computers. There are many harmful effects that could come with a computer virus. For example, a virus could delete important data, send out fake emails, and could possibly delete the information that contains on the hard drive. Therefore, it is important for a computer user to buy an anti virus system for his or her’s computer to avoid these terrible malfunctions that are very common in computers.[13]
Security Software is a Computer’s Doctor
Although computer viruses in the past were sometimes designed to create confusion and mischief, more recent viruses have been designed to inflict much more serious damage. The perpetrators of creating such viruses are
Cartoonvirus
more often working for foreign governments or intelli- gence agencies. In recent years there have been several viruses that have become well known due to the large amount of damage they caused. One such virus was called Conficker Virus and affected Windows-based Pc’s in 2009. This worm crawled through millions of comput- ers which created an immense botnet that was able to steal financial information and data. The virus is still affecting computers today. Another well known virus was called agent.btz and occurred in 2008. This virus spread through infected thumb drives and was found on Pentagon com- puters. It was believed to be the work of foreign spies, and lead to the creation of U.S. Cyber Command, an agency created to battle cyber war. PoisonIvy, another computer virus launched in 2005, allowed the attacker to control the infected user’s computer. This malware is known as re- mote access Trojan. It allows the hacker complete control of a computer. Once control is gained, the hacker could manipulate files and even get access to the computers speaker and webcam. PoisonIvy affected both defense and chemical industries in the West. Computer viruses are a serious threat. With the world relying on computers for everything from personal use to national defense, it is vital that computers be safeguarded against viruses. The next section goes on to describe security software.[14]
Data, Program or Website Alteration
Alteration attacks could take many different forms and occur when someone makes unauthorized modifications to code or data, attacking its integrity.[15] Alteration at- tacks have a range of consequences such as altering, de- stroying, suppressing, or stealing output, usually to con- ceal unauthorized transactions.[16] For example, students are changing grades, employees are altering or deleting corporate data as well as hackers changing social net- working accounts and posting statuses on victim’s behalf.
124 CHAPTER 4. NETWORKS AND THE INTERNET
Facebook Logo on Monitor
Many politicians like French President Nicolas Sarkozy whose Facebook page was hacked in 2011[17] are under website alteration attack. The government or corpora- tion website can be hijacked as well. In 1996 U.S. Cen- tral Intelligent Agency’s website was altered by Swedish hacker and in 1998 The New York Times’ website was hacked.[18] Although people may feel helpless against these attacks, victims of sabotage have the law on their side. A person who knowingly, willfully and without au- thorization creates, alters or deletes any data, informa- tion, image, program, signal or sound contained in any computer, system or network which, if done on a written or printed document or instrument is guilty of forgery.[19] In 2012, the IC3 (receives, develops, and refers crim- inal complaints of cybercrime) received and processed 289,874 complaints, averaging more than 24,000 com- plaints per month. Also, unverified losses reported to IC3 rose 8.3 percent over the previous year.[20]
Security Software
Security software are programs that run alongside the other programs on a computer to try and prevent viruses from penetrating into the system. If software does not prevent the virus with its defensive properties, then it can detect a virus and detect the user. Most viruses can be removed by security software, but if there is one that cannot be removed, the software will “corner” the virus so that it cannot ruin any other areas in the com- puter system. Viruses are a big problem for every com- puter that uses the internet, no matter what type of ac- tivity is done on the internet. Viruses can be used for theft, corruption of data, destruction of data, or system failure. The way to get security software is to down- load it digitally or through a DVD-ROM. According to the Anti-Virus Software website, the top ten anti- virus softwares are the following, respectively: McAfee, BullGuard, Trend Micro, Kaspersky, Norton by Syman- tec, BitDefender, ESET, ZoneAlarm, ParetoLogic, and VIPRE. These softwares provide web browsing protec-
tion, protection against Phishing scams, and parental con- trol in addition to the basic anti-virus features. The way to choose the best anti-virus software is to check out all of the details and features to determine what extra character- istics are really necessary and what price range is suitable for personal circumstances.[21]
4.5.3 Online Theft and Fraud
Identity Theft
Pennsylvania-Drivers-License-1
Identity theft is when someone identity in order to gain ac- cess to their bank accounts and possibly rent apartments or take out loans in that persons name. They then use their credit cards to make purchases. It usually begins when someone gets the name, address, and social secu- rity of someone from thrown a discarded document, usu- ally mail. They can also get people’s information form the Internet. Identity theft is typically grouped into two subcategories. One is true name identity theft and that is when the thief uses another person’s information to open new accounts. The other kind is account takeover, which is when the thief uses someone else’s personal informa- tion to gain access to their existing accounts.[22] There are different techniques such as skimming and social en- gineering. Skimming is when the thief uses a device that
4.5. SECURITY 125
reads and stores credit and debit card numbers and stores them for later retrieval by the thief. Social engineering is when you pretend to work at a bank and ask people for their information.[23] Thieves rummage through garbage, trash in business, public dumps to get what they are look- ing which is someone’s personal information. Some good indicators that your account identity has been stolen are if there are withdrawals that you can’t explain, not get- ting bills in the mail, refused checks, IRS contacting you, bills received that you are not aware of, and if your health plan will not cover you. All of these are big indicators that your identity has been stolen. It is important to be aware of bank transactions to be cautious of these thieves. There are certain types of Identity theft as well. Tax re- lated would be one of them. If a Social Security number is stolen that can be used to get a tax refund or job. If you get paid by someone you do not know or find more than one tax return those would be big indicators that someone stole from you. Contacting the right people im- mediately would be the first thing to do in any situation dealing with identity theft. The IRS can help if a So- cial Security number has been stolen and they can protect the account. Children can also have their Social Security number stolen so it is important to keep that information private and on file.[24]
Phishing
Phishing is when a thief sends out an e-mail that looks like it is from a legitimate site and then they steal your information. They are typically sent to a large group of people and they include an urgent message. It usually says that they need to update their banking information or something to that affect. Phishing attempts can oc- cur anywhere, including Twitter, MySpace, or e-bay.[25] Something that is becoming more targeted is spear phish- ing. Spear phishing e-mails are personalized. It is often targeted to social media sites because it is easier to find personal information on people.[26]
Pharming, Drive-by Pharming, and Online Auction Fraud
Many people today are victims of identity theft. Another type of fraud or scam is called Pharming. Pharming is usually a fraudulent domain name intended to redirect a website’s traffic to another “trick” website. Pharming can be conducted either by changing the hosts file on a vic- tim’s computer, or by the exploitation of a vulnerability in DNS server software.[27] Sometimes this happens via email. The hacker gets ahold of the user’s email address
Online Fraud
and sends the code or website to the specific user. Once the user receives and opens the email, the hacker can re- ceive the user’s information. Pharming usually happens most often with DNS servers at a company with a com- mon and well-known Web site. The hacker can change IP addresses intended for the company URL. Then the com- pany URL is routed to the “poisoned” URL, which then takes over the Web server. This method of pharming is useful to the hacker because the “poisoned” Web site is usually made to look exactly like the company Web site. Once the user logs in, the hacker captures the username and password for the first time. The user receives a login message error and is then returned to the original com- pany Web site. Drive-by Pharming is a little more recent. This method is used by logging into the user’s personal routers by using a common password that a script within a website can run. When it is accessed, the information on the router can be modified to suite the hacker.[28]
Online auction fraud happens when a payment online goes to the seller, but the item is never delivered. For instance, if a buyer wants to make a bid online and buy tickets to a show or a concert, the buyer pays the seller for the tickets, and the seller never sends them. Many people are scammed each year and need to be careful with who they are trusting over the Internet.
4.5.4 Protecting Against Online Theft and Fraud
Protecting Against Identity Theft
Just as the Internet is always evolving for good, there are also constantly scheming e-criminals hoping to take ad- vantage of those who aren't careful with their online iden- tities. Identity Theft is one of the scariest things that can happen to a person, especially if they don't have a strong friend or family base to help convince the proper authorities of their true identity. There is no one universal
126 CHAPTER 4. NETWORKS AND THE INTERNET
The key to internet safety is always being self aware.
way to protect yourself from identity theft; instead, there are a number of steps you should take to keep yourself fully protected. The first thing you can do is be respon- sible with your bank accounts and credit cards. If you're checking your balance every day, you will be quick to see if there are any suspicious discrepancies occurring.[29] The next important step to protect against identity theft seems simple but can be easily overlooked: do not give out your personal information on the internet. This in- cludes phone numbers, addresses, or anything else that hackers could potentially trace back to something you hold valuable. One of the final ways you can protect your- self from identity theft is being wary of your mail. It is very easy for an e-criminal to send you a destructive link in an email that looks like it came from one of your friends, where one small click will lead you into a world of pain. Just follow these few rules and you will be doing fine online.
Avoiding Phishing E-mails
Most e-mail programs will automatically disable links in e-mail messages identified as questionable.
Due to the advantage taken of today’s improving technol- ogy, phishing has emerged as one of the most damaging forms of identity theft. Using very convincing and per-
sistent language, e-criminals are able to trick millions of users into revealing confidential information over the In- ternet. As mentioned earlier, to lure people in to click- ing an attached link, e-criminals tend to steal the iden- tity of a legitimate and well-known company to write a very “important-sounding” e-mail, solely for the purpose of tricking the reader into thinking the contents of the e- mail really are significant. Nonetheless, however urgent the e-mail may seem, it is actually designed to steal your money! A typical phishing e-mail will usually consist of: spelling errors, links, threats to make the content seem urgent, and a popular company name to sound reliable. If examined carefully, some phishing expeditions may be fairly easy to spot, due to the poor spelling and gram- mar used, making it obvious that the message is not from a legitimate company. The link in the e-mail is used by the cybercriminals to install malicious software on your computer, ultimately enabling them to steal personal and sensitive information off of your computer. The e-mail could also even ask you to provide personal information, such as your bank account number, credit card number, or your Social Security Number; this should automati- cally be a red flag for the recipients because an authentic business would never request such information in any way other than in person. Therefore, if one is alert and careful about the content they receive in an e-mail, they can ul- timately help protect their identity and their money, even if the e-mail seemed rather urgent.
Phish
The act of a phisher setting up a Web site that appears to look like the legitimate business is an act called Web site spoofing. As mentioned above, phishing emails can be sent to a wide group of people or can be personalized and sent to one person. This more targeted trend of phishing is called spear phishing because it targets a specific indi- vidual. A phisher may gather personal information from a networking site and send an email to a particular indi- vidual in order to convince the recipient that personal lo- gin information or account information is needed. Phish- ers may also doing something that is called typosquat- ting, which is setting up spoofed Websites with addresses slightly different from legitimate sites in the hopes that a user would supply login information via the spoofed site
4.5. SECURITY 127
when they arrive. Another form of online threats include pharming. Pharming is another type of scam that uses spoofing. With pharming, the criminal reroutes traffic intended for a commonly used Web site to a spoofed Web site set up by the pharmer. The pharmer makes changes to the DNS server. The DNS server is the computer that translates URLs in to the needed IP addresses to display the Web page corresponding to a URL. A pharmer will usually target company DNS servers. Lastly, online ac- tion fraud can also be a concern for Internet users. This threat occurs when an online auction buyer pays for mer- chandise that never is delivered.[30] [31]
Digital Certificates
Box showing digital certificates
One way of protecting yourself from online thefts or frauds is by looking for a digital certificate when brows- ing the Web or looking through e-mails. A digital cer- tificate is granted by Certificate Authorities, which prove to the person that the website they are accessing is se- cure. A digital certificate binds the owner of a website to a specific pair of electronic keys, one being public and the other private. This allows the owner of the certificate to encrypt their files and e-mails and provides the user with the knowledge that their actually is an owner to the web- site that they are on. This can protect users from giving away their credit card numbers to unprotected websites that try to scam people of their money. A digital certifi- cate can either be an SSL or EV (Extended Version) SSL. The SSL digital certificate is the ordinary certificate that still requires an application and verification process while the EV SSL requires a more in-depth verification process.
For users, an EV SSL digital certificate indicates that it is more secure than just an SSL digital certificate, while both of them are considered to be safe. This can be rep- resented by the fact that when you enter an EV SSL web- page, the Address bar turns green and for an SSL web- page it doesn’t change color at all. A digital certificate, in general, is definitely a good security advisor for users on the Internet.[32]
The Safety of Using PayPal
Credit-cards
Internet users have to be very cautious of the information they put on the internet. PayPal seems to be a popular e-commerce business that many people use and willing give their private information to. Is this payment pro- cessor to be trusted? PayPal makes the lives of every- day internet consumers much easier. Its secure server stores your credit card information so payment over the internet is more efficient. Not much effort has to be put in by the individuals that use this payment processor. Other accounts require a vast amount of paper work to be signed beforehand.[33] One drawback to using PayPal is that there is a long list of rules the users must abide by, and if a user breaks any of these rules their money could be locked for up to six months while under investigation. An interesting feature that was added to PayPal in 2006 was an additional security option. Instead of only entering a login id and password, PayPal users can choose to type a six-digit number code in as well. This lowers the risk of malware bots trying to hack into the account. The only bad part is that there is a fee associated with this added security measure. Users might be discouraged to protect their accounts because of this additional fee. They should still take caution when it comes to entering personal in- formation into PayPal.
The Safety of Digitally Storing Cards
Now with the advancement of technology and the new innovations of companies like Apple and Google. New forms of paying have appeared or rather a new way of
128 CHAPTER 4. NETWORKS AND THE INTERNET
A new way of paying. But is it safe?
paying. Apple Pay and Android Pay are ways of pay- ing wherein the user puts their credit cards or debit cards into their phones and can then use their phones or smart- watches to use their credit cards instead of bringing the physical cards with them. With the phone’s it uses bio- metrics to make sure the owner is using Apple Pay and with smartwatches they use passcodes. But the real ques- tion is this new way of paying secure? Apple claims that it is so. In fact, they claim that it is actually more secure and that they will never upload the details on your cards to their servers. In fact, if your smartphone or smartwatch was ever stolen, you have the ability to revoke the infor- mation on your smartphone or smartwatch. Also Apple creates a Unique Device Account Number in order to protect your purchases when making transactions. How- ever, there are those who do believe that this may not be safe. The best way to not have to deal with the risk is not actually use Apple Pay. Although that depends on the person.[34]
Basic Home Network Security
An icon of a wireless router, the kind of device one uses for the networks ones needs to keep secure.
Many people have wireless networks in their homes, but they may not necessarily keep these networks as safe as
they can or should. If somebody else accesses your net- work without your knowledge or consent, then they may do things on that network that you do not desire, they may eat up your allotted data usage, and, most concerning, they may be able to get your personal information. There- fore, people with wireless home networks should take precautions to keep them secure. First, networks should always have some sort of a password to keep them safe; a network should never, ever be left unsecured, because then absolutely anybody within range can go on it. Typing any password at all is better than nothing, since it'll de- ter people from mooching, but—as is always the case— it is not wise to go with a predictable password such as the network name, 'password', 'Internet', etc. Something that is meaningless on the surface level but has a deeper meaning for you is a better way to go; for example, the first letters of words in an individual phrase that only you will remember. Also, to add yet another layer of secu- rity, you can make it so that your network is not available to other users by default but instead they must know the network name; this way, for a hacker to gain access, they would have to guess both the ID of the network and the password, which is highly unlikely. With these incredi- bly simple steps, one can make their network incredibly secure compared to one that has absolutely no measures preventing access from anybody within a certain physical proximity.[35]
4.5.5 Personal Safety
Only starts with one message
Cyber-bullying
This is a new way of bullying especially for the amount of social networks and how it has influenced our soci-
4.5. SECURITY 129
ety today. Unfortunately, it happens 24 hours of the day and anything can be posted or distributed anonymously in which it could be difficult to track where the bullying is coming from. And as everyone is informed these days, once something is on the internet, there is no way to per- manently delete the comment after it has been sent. It happens when individuals are bullied through electronic technology. For example, you can cyber bully over text message, emails, rumors send through any type of social networks. There’s no way to prevent an individual from making a comment that could be known as the start of cyber bullying, but simply ignoring or reporting the com- ment to either a parent, friend or any type of guidance person could benefit you most in not having the bullying continue. To elaborate, you can simply block the individ- ual that had started the commenting and keep any type of evidence of the bullying for future documents in case it gets worse. A last important note is to recognize the signs of attitudes if a student were to be cyber bullied; some re- actions are abusing drugs and alcohol, skip school, receive poor grades and have lower self-esteem.[36]
Cyberstalking
Cyberstalking is a serious issue.
Cyberstalking is the use of the internet, email, or other electronic communications to stalk another person. This occurs when there is a continuous pattern of malicious or threatening activity from an individual. Cyberstalk- ing is considered the most dangerous form of harassment over the internet and is punishable by law. Depending on the state, punishments can range from misdemeanors to felonies.[37] Victims of cyberstalking can be targeted by strangers online who find personal information some- where on the web or by more personal colleagues or indi- viduals who know the person they are targeting well. Un- fortunately, cyberstalking can move beyond the computer and become a problem in the real world if the stalker dis-
covers or knows how to find the individual personally. This is a very serious issue and should be brought to law enforcement agencies or even the FBI. It is important to not give away any personal information that can be used to stalk you and to ensure that you trust anyone or anywhere that you may be giving personal information to online. The best solution to stop cyberstalking is to not respond at all or to change the information on what ever resource the cyber stalker is using to harass you.[38]
Online Pornography
Protecting the Children
Along with the lifespan and constant evolution of the In- ternet came the controversial issue of online pornogra- phy. Though pornography has unfortunately been around on paper for centuries, electronic access has made it much easier, quicker, and more convenient for any individual to get ahold of it at any given time. With this online access comes a much bigger and more controversial is- sue. It has introduced people, especially children, to new and substantial safety issues. Though child pornography is banned and illegal, there is a considerable amount of it being circulated and passed throughout the Internet. With the link that has been made between this horri- ble content and child molestation, it is reasonable to be concerned about the spike that this will bring. Not only does it encourage sick people to do horrible things, but the computer also gives them an outlet to meet and dis- honestly introduce themselves to children. It is unfortu- nate that today we have to be concerned about what could come from our children talking to people on the Inter- net; however, it is important that we voice these risks and make sure that parents take every precaution possible to keep their children from ever experiencing these horrific possibilities.[39]
4.5.6 Protecting Against Cyberbullying, Cyberstalking, and Other Personal Safety Concerns
130 CHAPTER 4. NETWORKS AND THE INTERNET
Safety Tips for Adults
Be careful what you send
While it may seem unnecessary to state, the Internet is accessed by not only those with good intentions but also those who can pose a threat in a variety of ways. It is important to be aware of this fact because it is quite easy to forget how vast of an entity the Internet is and count- less masses who use it daily. This makes for the task of safeguarding information from those who mean harm an important responsibility. Some of the ways one can pre- vent cyberbullying, cyberstalking and other issues are by using names that are gender-neutral. This hides the iden- tity of the user, and this is important for female users because unfortunately they are more likely to be targets compared to male users.[40] Also, one should not give phone numbers, addresses and other personal informa- tion to strangers for obvious reasons.
Safety Tips for Children and Teens
Monitoring how children and teenagers use the Internet through the computer, smartphone, game console, etc. is the most important step in protecting them. It is recom- mended to place certain restrictions on how they use the Internet so that they do not access certain sites that might make them more susceptible to dangerous individuals or certain sites (e.g. adult sites). It is also important for older teens to understand the potential ramifications, including not only personal but also legal issues, that can arise from sending explicit messages or pictures via text messaging.
Using Your Computer In A Safe Way
One of the best ways to stay safe online is to make sure you have your computers operating system and antivirus / anti-malware software update and set scanning schedules however the most important part of protection is user awareness. A recent blog post from Antivirus Talk de- tails a list of good computer rules. Remember the ma- jority of the time the user has allowed a virus onto the system. [41]
• Always Run Antivirus Software
• Don’t Go To Websites You Don’t Know
• Don’t Open Emails if you don’t know where they are from
• Use A Different Password For Everything
• Keep Your System Up-To-Date
• Don’t install unknown programs
By just following these rules you have the best chance of a safe journey online.
4.5.7 Network and Internet Security Leg- islation
DC3 seal
New legislation is frequently introduced to address new types of computer crimes. Unfortunately, it’s difficult to keep pace with the rate at which the technology changes. Along with this, there are both domestic and international jurisdictional issues because many computer crimes af- fect people in geographical areas other than one in which the computer criminal is located. Regardless, computer crime legislation continues to be proposed and computer crimes are being prosecuted. Some of the most important and impactful laws follow: Computer Fraud and Abuse Act of 1984- Makes it a crime to break into comput- ers owned by the federal government. Identity Theft and Assumption Deterrence Act of 1998- Makes it a federal crime to knowingly use someone else’s means of identifi- cation, Social Security number, or credit card, to commit any unlawful activity. Homeland Security Act(2002)- In- cludes provisions to combat cyberterrorism. One of the
4.5. SECURITY 131
most famous cases of a cyber crime happened quite re- cently, the criminals charged in 2013. Five cyber crim- inals were responsible for a hack that targeted compa- nies more than $300 million. They did this by stealing usernames and passwords, personal identification infor- mation, credit card and debit card numbers through se- cure computer networks. The criminals were sentenced up to 20 years in prison, depending on the amount stolen and involvement with the hacking group.[42]
[1] http://us.norton.com/
[2] http://windows.microsoft.com/en-us/windows/ security-essentials-download
[3] http://www.networkworld.com/article/2255950/ lan-wan/chapter-1--types-of-firewalls.html
[4] http://www.bullguard.com/bullguard-security-center/ pc-security/computer-security-resources/ how-proxy-firewalls-work.aspx
[5] http://web.mit.edu/kerberos/firewalls.html
[6] http://www.biometricupdate.com/201308/ human-recognition-systems-integrates-biometric-access-control-with-cscs
[7] https://en.wikipedia.org/wiki/Access_control#Access_ control_system_components
[8] http://en.wikipedia.org/wiki/Wardriving
[9] http://en.wikipedia.org/wiki/Keystroke_logging
[10] http://us.norton.com/travel-hotspot-security/article
[11] http://download.cnet.com/ Malwarebytes-Anti-Malware-Free/3000-8022_ 4-10804572.html
[12] http://www.ucalgary.ca/it/help/articles/security/ awareness/botnets
[13] http://www.ucalgary.ca/it/help/articles/security/ awareness/botnets
[14] http://www.smithsonianmag. com/ist/?next=/science-nature/ top-ten-most-destructive-computer-viruses-159542266/
[15] http://www.sans.edu/research/security-laboratory/ article/alter-code
[16] http://en.wikipedia.org/wiki/Computer_crime
[17] http://www.nydailynews.com/news/ facebook-hackers-french-president-nicolas-sarkozy-resign-article-1. 150369
[18] http://www.britannica.com/EBchecked/topic/130595/ cybercrime/235711/Sabotage
[19] http://law.justia.com/codes/nevada/2013/chapter-205/ statute-205.481
[20] http://www.fbi.gov/news/pressrel/press-releases/ ic3-2012-internet-crime-report-released
[21] http://www.top10antivirussoftware.com/
[22] http://money.howstuffworks.com/identity-theft.htm
[23] http://legal-dictionary.thefreedictionary.com/identity+ theft
[24] http://www.consumer.ftc.gov/articles/ 0040-child-identity-theft
[25] http://searchsecurity.techtarget.com/definition/phishing
[26] http://searchsecurity.techtarget.com/definition/ spear-phishing
[27] https://en.wikipedia.org/wiki/Pharming
[28] http://highsecurity.blogspot.com/2007/02/ pharming-and-drive-by-pharming.html
[29] http://electronics.howstuffworks.com/how-to-tech/ how-to-protect-against-identity-theft2.htm
[30] https://www.fdic.gov/consumers/consumer/alerts/ phishing.html
[31] http://www.microsoft.com/security/online-privacy/ phishing-symptoms.aspx
[32] http://technet.microsoft.com/en-us/library/dd361898. aspx
[33] http://www.xsitepro.com/ the-pros-and-cons-of-using-paypal-as-your-primary-payment-processor. html
[34] http://www.express.co.uk/life-style/ science-technology/591309/ Apple-Pay-UK-Launch-Safe-Safer-Contactless-Credit-Debit-Card
[35] http://www.pcworld.com/article/130330/article.html
[36] http://www.stopbullying.gov/cyberbullying/what-is-it/ index.html
[37] http://www.ncsl.org/research/ telecommunications-and-information-technology/ cyberstalking-and-cyberharassment-laws.aspx
[38] http://www.cyberangels.org/security/stalking.php
[39] http://www.popcenter.org/problems/child_pornography/
[40] http://www.cyberbullying.us/research.php
[41] http://www.antivirustalk.com/
[42] http://www.bloomberg.com/news/2013-07-25/ 5-hackers-charged-in-largest-data-breach-scheme-in-u-s-. html
132 CHAPTER 4. NETWORKS AND THE INTERNET
4.5.8 Review
Important Terms antivirus software
[1]
Software used to detect and eliminate computer viruses and other types of malware. biometric access system: An access control system that uses one unique physical characteristic of an individual (such as a fingerprint, face, or voice) to authenticate that individual. bot: A computer that is controlled by a hacker or other computer criminal. botnet: A group of bots that are controlled by one indi- vidual. computer crime: Any illegal act involving a computer. computer sabotage: An act of malicious destruction to a computer or computer resource. computer virus: A software program installed without the user’s knowledge and designed to alter the way a com- puter operates or to cause harm to the computer system. computer worm: A malicious program designed to spread rapidly to a large number of computers by sending copies of itself to other computers. cyberbullying: Children or teenagers bullying other chil- dren or teenagers via the Internet. cyberstalking: Repeated threats or harassing behavior between adults carried out via e-mail or another Internet communications method. denial of service (DoS) attack: An act of sabotage that attempts to flood a network server or a Web server with so much activity that it is unable to function. digital certificate: A group of electronic data that can be used to verify the identity of a person or organization; includes a key pair that can be used for encryption and digital signatures. digital signature: A unique digital code that can be at- tached to a file or an e-mail message to verify the identity of the sender and guarantee the file or message has not been changed since it was signed. dot con: A fraud or scam carried out through the Internet. encryption: A method of scrambling the contents of an e-mail message or a file to make it unreadable if an unau- thorized user intercepts it. firewall: A collection of hardware and/or software in- tended to protect a computer or computer network from unauthorized access. hacking: Using a computer to break into another com- puter system. (I bet you need this for class.) identity theft: Using someone else’s identity to purchase goods or services, obtain new credit cards or bank loans,
or otherwise illegally masquerade as that individual. malware: Any type of malicious software. online auction fraud: When an item purchased through an online auction is never delivered after payment, or the item is not as specified by the seller. password: A secret combination of characters used to gain access to a computer, computer network, or other resource. pharming: The use of spoofed domain names to obtain personal information in order to use that information in fraudulent activities. phishing: The use of spoofed e-mail messages to gain credit card numbers and other personal data to be used for fraudulent purposes. possessed knowledge access system: An access control system that uses information only the individual should know to identify that individual. possessed object access system: An access control sys- tem that uses a physical object an individual has in his or her possession to identify that individual. private key encryption: A type of encryption that uses a single key to encrypt and decrypt the file or message. public key encryption: A type of encryption that uses key pairs to encrypt and decrypt the file or message. secure Web page: A Web page that uses encryption to protect information transmitted via that Web page. security software: Software, typically a suite of pro- grams, used to protect your computer against a variety of threats. spear phishing: A personalized phishing scheme tar- geted at an individual. Trojan horse: A malicious pro- gram that masquerades as something else. two-factor authentication: Using two different methods to authen- ticate a user. unauthorized access: Gaining access to a computer, network, file, or other resource without per- mission. unauthorized use": Using a computer resource for un- approved activities. virtual private network (VPN): A private, secure path over the Internet that provides authorized users a secure means of accessing a private network via the Internet. war driving: Driving around an area with a Wi-Fi- enabled computer or mobile device to find a Wi-Fi net- work to access and use without authorization. Wi-Fi pig- gybacking: Accessing an unsecured Wi-Fi network from your current location without authorization.
Questions 1. Which of the following is an example of something used to gain access to a possessed object access system? [2]
a. password
4.5. SECURITY 133
b. smartcard c. username d. pin 2. The most common type of possessed knowledge, com- prising secret words or character combinations associated with an individual, are: a. security keys b. passcodes c. usernames d. passwords Fill in the blanks: 3. Driving around looking for a Wi-Fi network to access is referred to as ________. 4. _______ access control systems use some type of unique physical characteristic of a person to authenticate that individual. 5. A(n) ____________ can be used at a Wi-Fi hotspot to create a secure path over the Internet. 6. A(n)____________ can be added to a file or an e-mail message to verify the identity of the sender and guarantee the file or message has not been changed. True or false? 7. A computer virus can only be transferred to another computer via a storage medium. 8. An access control system that uses passwords is a pos- sessed knowledge access system. 9. Using a password that is two characters long is an ex- ample of two-factor authentication. Answer 10. Secure Web pages use encryption to securely transfer data sent via those pages.
Answers [3]
1. b 2.d 3. war driving 4. Biometric 5. virtual private network or VPN 6. digital signature 7. F 8. T 9. F 10.T
[1] http://coursemate.cengage.com/CPReader/View/ 9781133114598/default.aspx?eISBN=9781133114598# 53c50e83-32b2-46bf-8d09-fe73e2cb62b2
[2] http://coursemate.cengage.com/CPReader/View/ 9781133114598/default.aspx?eISBN=9781133114598# 4dc6772a-b649-4893-be5d-6acb8ff8bead
[3] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013935
Chapter 5
Business on the Web
5.1 Multimedia
5.1.1 Web-Based Multimedia
Overview
Multimedia
Whether you know it or not, you have seen multimedia and you should be semi familiar with it. Multimedia is exactly what is sounds like, multi (many) media (pictures, video, etc.). If you go to humble bundle.com[1] you will see an excellent assortment of multimedia. You have a countdown, which is your animation, you have images of the games you can get. When you click on an image you will get an expansion showing you a description and an embedded YouTube[2] video. Now that you understand the basics you can see all of the different uses of multime- dia in your favorite websites. While this sounds great and having multimedia will make any site better, remember too much of anything is not good.
What Is It? Multimedia refers to the literal combina- tion of multiple types of media. Web-based multime- dia, however, is a term used to describe the multime- dia (sound, video, or animation, text and images) found within web pages. Similar to others, web-based multi- media pages display information requested by the user through hyperlinks. Multimedia web sites are interactive, often containing elements with which the visitor directly works. Examples of this would be playing or pausing a video clip or game, and controlling a 3D object. At one point, web-based multimedia was strictly limited as both computers and internet services were too slow to support it. Over time, the significant increase in computer and broadband connection speeds have Web-based multime- dia possible, and the success of Web-based multimedia is growing rapidly. The vast majority of sites today fea- ture some form of multimedia. For instance, it is often used in advertisements, as regular site content (TV shows and photos posted by TV networks or podcasts), informa- tional videos of available products offered by companies, or as “user- generated content”, such as videos uploaded to YouTube or pictures uploaded to Flickr. [3]
Web Based Multimedia Applications come in a wide variety and can be found all over the Internet. A website that contains more than one type of media is considered to be multimedia. Sites that contain sound, video, an- imation, and/or images alongside text fall into this cat- egory. Typically, these sites use multiple applications such as these to convey certain information to the viewer of the web page. Manufacturers might use photos and PDF based user’s manuals to transfer key points of inter- est about their products to the viewers. In other cases, multimedia can be used as a teaching tool where visitors learn through instructional videos or a news site might use podcasts and television footage to update their read- ers through their websites. Images and sound are also em- ployed by many musicians when visiting their sites along- side the text-based dates of their tour. Entertainment also plays a large factor in web based multimedia applications. With the rise of Internet video streaming, people can now watch their favorite t.v. shows when they have the free time to do so, and from anywhere there is an Internet con- nection. Websites like Netflix and Hulu use sound, video, and often thumbnail photo icons alongside their descrip- tive text of the shows available. Some things to keep in
134
5.1. MULTIMEDIA 135
mind concerning these multimedia applications are Inter- net connection speed and bandwidth. Most of these video streaming websites; whether news, sports, or t.v. shows, etc. require a minimum broadband connection speed of 500Kbs for standard definition viewing. The minimum speed requirement increases as the definition increases and vice versa. Bandwidth plays an important role as well since some service providers put a cap on the amount of information that can be processed. Most “smart” phone service providers set a cap of 1Gb or 2Gb a month and charge additional fees if this ceiling is ignored. Consid- ering that a standard definition, one hour t.v. show can be close to 200Mb, it is wise to pay attention to the band- width being consumed as this can rapidly add up.[4]
Text instructions assisted by picture instructions
There are many advantages that web-based multimedia can offer. One of the biggest benefits of web-based mul- timedia is that it can address many different types of learning styles. For example, when being taught how to make a paper airplane, someone may prefer written in- structions, while someone else may prefer picture instruc- tions. Multimedia can offer picture instructions with cap- tions in order to meet both people’s learning styles. An- other advantage of web-based multimedia is that it can make information more enjoyable and interesting to a user. Text-only information can get very boring, but mul- timedia could be implemented in order to spice up a web- page. For example, when learning where countries lay on a map, a simple picture might not portray the information in an enjoyable fashion. With multimedia, an interactive map could be created and used instead of a picture. An interactive map may be a more enjoyable way for a user to learn the material due to the fact that they must engage with the multimedia. Along with web-based multime- dia’s advantages come disadvantages. One disadvantage of web-based multimedia is that it can be very costly and time consuming.[5] Websites that use multimedia gener- ally take more time and skill to develop than a text-based
website. Businesses often hire someone to create and ar- range multimedia on their webpages.[6]
Augmented reality app used at a museum
Augmented Virtual Reality Augmented Virtual Reality is the augmenting or adding- on of certain computer-generated elements to the real world usually through a display. Augmented Virtual Re- ality can be applied to many different types of technolo- gies and industries and is currently growing within e- commerce. Some companies, such as IKEA are using the technology of Augmented Virtual Reality to give con- sumers a better view of how furniture will look in their home. Other uses include the application of Augmented Reality within the automobile industry. Certain manu- facturers are utilizing the technology within windshields. This is known as Head-Up-Display and is used to allow drivers to see their MPH, fuel gage, and many other infor- mation that you would need while driving, without forc- ing them to take their eyes off the road. Another use of Augmented Virtual Reality is with Google Glass. Google Glass allows users to have all the features of a phone within a display on their glasses and with the use of voice commands. Also, some developments are being made to incorporate Augmented Virtual Reality within the medi- cal field. Although Augmented Virtual Reality is a recent development, it is being used more and more within many devices and will possibly be a social normality within a few years.[7]
5.1.2 Multimedia Elements
The Five Multimedia Elements
Text, image, audio, video, and animation are the five multimedia elements. The first multimedia element is text. Text is the most common multimedia element. Text expresses the information the developer is trying to get across to their viewers. Even though pictures grab the viewers’ attention, text is a good idea to include, as well, just in case the picture does not load. The second multi- media element is image. An image catches the viewers’
136 CHAPTER 5. BUSINESS ON THE WEB
Animation
attention much more quickly than just plain, old t for cre- ating these animations. Animations are the most creative and fun multimedia element! [8]
A serif font, on top, and a sans-serif font, on the bottom.
Serif vs. Sans-Serif Fonts & Font Choice All fonts, or typefaces, are either serif or sans-serif. “Serif” is Latin for “with feet,” while “sans-serif” is Latin for “without feet”, and that is the difference: serif fonts have small lines, or serifs, at the bottom of the letters, as if the let- ters have feet. Sans-serif fonts lack these “feet.”[9] Times
New Roman is the most common and easily recogniz- able serif font, while the most common and recognizable sans-serf fonts are Arial, Helvetica, and Comic Sans MS. There is some disagreement about whether serif fonts are easier to read than sans-serif ones, or vice versa, but in general, serif fonts are preferred for large bodies of text, especially on physical, printed materials, while sans-serif fonts are preferred for smaller things, such as headlines, and electronic messages.[10] Even past the question of whether to use a serif vs a sans-serif font, one should be careful about which specific font one is using. Differ- ent typefaces carry different connotations. A potentially more formal font, such as Times New Roman, would not be suited to something more informal like an invitation to a young child’s birthday party; likewise, an informal font like Comic Sans would be very inappropriate for formal messages. When choosing a font, consider the purpose of the message and the audience.
Video
Video Camera
Video provides a powerful impact in a multimedia pro- gram. It starts with continuous event and breaks it up to frames, whereas an animation starts with frames. Video formats are made up of container and codec(s). The con- tainer describes the structure of the file like where the various pieces are stored, how they are interleaved, and which codecs are used by which pieces. A codec is a way of compressing the file to decrease file size, while main- taining quality.[11] Some of the most common video file formats are Audio-Video Interleave (.avi), Flash Video Format (.flv), Moving Picture Experts Group 2 (.mp2), Moving Picture Experts Group 4 (.mp4), QuickTime (.mov), and Windows Media Video (.wmv).[12] In mul- timedia applications, the digital video is gaining popular- ity because the video clips can be edited easily, it can be stored like any other files in the computer and the qual- ity of the video can still be maintained, and the video can be transferred within a computer network which al- lows non-linear editing in any part of the video.[13] Just like in audio, in streaming video the traveling informa- tion is a stream of data from a server. In 2006, people watched more than a million streaming videos a day on
5.1. MULTIMEDIA 137
YouTube.[14]
Chameleon GIF
JPEG, GIF, and PNG Formatting GIF and PNG are two different formats which images are available in. GIF simply means Graphics Interchange Format and is typ- ically used for animations and sometimes single images as well. The images are compressed or made smaller; they are using what is called loss-less data compression. This compression makes it so that the image does not lose quality even if it is compressed due to its ability to have uniformed color with well-defined edges. A GIF is not the best quality format for images because of its limit of colors, which is one of the reasons that PNG was created. PNG are Portable Network Graphics. Their ability to compress is higher quality and allows for alpha transparency, which is basically creating the image with a background so that it looks transparent either partially or fully.[15] They can store more color depth but also take up more space than GIFs in some cases. In cases where this does not apply it is because their ability to have bet- ter compression in 8-bit data ends up being smaller than GIFs.[16] PNGs are unlike GIFs because they do not sup- port animations, and are a single-image based format.[17] These formats are used in many Web pages today and are both arguably as important.
Example of a .jpg image
The Joint Photographic Experts Group committee cre-
ated the file format that is otherwise known as JPEG. JPEG is a technique and file format used to compress color images, digital photos, and other digital graphics. Many users who store photographs on their computer will recognize the JPEG file extension recognized as “.jpeg”, or “jpg”. The file size of a selected image can be opti- mized for different uses, otherwise known as editing a photo to the desired sizes. The file format does so by us- ing a type of compression of the image known as “lossy compression”. The definition of lossy compression is de- fined as the ability for the image to decrease in file size, taking away a slight decrease in image quality. JPEG files are widely used by consumers as a way to save photos on their computer to view at their desire. However, a user may have interest in sharing these images through e-mail, or a website. As considering using a JPEG file on a web- site or through email, a user must consider the file size in comparison to the amount of quality of the image. For in- stance, if a user is interested in posting a photograph on a website of theirs, they must consider file size and format- ting. Also, with e-mail, a user must consider the quality of the image they will be sending. The higher the quality of the image being sent, the larger the file size must be. If a user is sending this file over their cellular phone, it may require the use of more data to send a larger file size.[18]
Audio
Mp3
There are many different types of audio files, and the each have their of distinct advantages. The most ubiquitous audio file is the MP3. MP3’s have become the standard audio files on most devices and on most websites. The ad- vantage of MP3 file over different formats is their small size. MP3 files can be compressed, as they do not contain the inaudible sections of an audio track. While this results in good quality audio, while taking up a small amount of space, in certain situation, audio quality can suffer. The compression of MP3 file can distort vocal sounds, and can result in a ‘tinny’ sound. Because, some computers, primarily Windows-based PC’s use WAV files to store au- dio files. These files are uncompressed, so they take up a large amount of space, but they are of better quality than most MP3 files. As most desktop PC’s have room to spare, better audio quality is substitutes for more space used. Another file type common on windows computers
138 CHAPTER 5. BUSINESS ON THE WEB
is WMA. This format is optimized for use by Windows Media Player. Is primary advantage is that is copyright protected, but it can only be used on Windows Media Player. Another common audio file is DCT. This type of file is encrypted, and used for medical applications where patient confidentiality is needed.[19]
5.1.3 Multimedia Web Design
Basic Design Principles
The main thing about designing a website is that the whole point is to create a site that is interesting and will bring customers or people to look at it. Not only that, but you have to keep it interesting; people don’t want to see the same things on a website at all times. It needs to be up- dated and changed as time passes. Another important thing to remember is that many people aren't that tech savvy. It is important to keep the website somewhat sim- plistic. Confusing websites draw people away. It is im- portant to make sure your webpages load quickly, which can be done by choosing multimedia elements carefully and to modify them as necessary, like optimizing pho- tos to make them run as efficient as possible. Nowadays another important thing to consider when creating a web- site is whether or not people are going to be able to view it from other devices such as their phones, their tablets, or whatever else. It may be beneficial to also create a mobile version of the site. Its important to look at what browser people can use for this website. Some sites have certain features that can only be accessed by certain browsers, it is important to make sure to use features that work well on all common browsers. It would also be beneficial to use features that don’t require plug-ins. When people visit a site they are not going to want to have to install something just to go on the site or to access something on the site. It is also important to look at the size of the page content.[20] You want to be sure that your information can be seen on all computer screens. Web site design can be extremely time consuming and costly. Successful businesses and agencies typically have both the time and the money to have intricate web sites designed. However, for a company just starting out, those things may not be available yet. Fortunately, there are many sites today that offer free website design. Some great sites that offer this are Wix.com, Weebly.com, Yola.com and Moonfruit.com. This could be a great way for a brand new company or organization to be able to get their name out on the web and begin getting some recog- nition. These free sites make it easy for one who may not know much about web design, as they typically offer easy to use templates and offer step by step instruction along the way to guide one through the design process. Although the web design site is free, users will first have to purchase a domain name. These are available at compa- nies such as GoDaddy, Register.com, Domaine.com and Dyn.com. After purchasing a domain name, it is time for
Web Design and Development
the user to begin filling his site with content. The user has a great deal of freedom in customizing his site to contain the elements desired. Many of the sites mentioned earlier also provide tutorials to help get the site up and running. After the design of the website is complete, the creator can now publish it and get ready for some recognition. It is important for the creator to update the website often and to market the site as much as possible. For any orga- nization or company that may be just getting off its feet, deciding to use a free site to do its web design might be a good option, and with so many sites offering this service, it seems silly not to.[21]
Using Flow Charts, Page Layouts, and Storyboards
When talking about website design, a flowchart is used to show how different web pages relate to each other. A flowchart is basically a map of the website. There can be links between the lines of the flowchart to take you where you want to go. When designing a website, you can make it as simple or as complicated as you want. Often times, the flowchart is designed in the early stages of the web- site because it provides a good building ground for the website.[22] Page layout is used in the designing of a web- site. Typically people create two page layouts; one for the home page and one for all the other pages. This is when you design where you want the different logos, like the home page button, and its when you decide how visually exciting you want your website. While it’s important to make it visually interesting, it is also important to keep it simple so that it does not get too confusing.[23] Story- boards are also something commonly used in website de- sign. Storyboards are a series of pictures that depict what is going to happen on each screen. They are typically used when creating something animated.[24]
5.1. MULTIMEDIA 139
How to Start a Storyboard There are a few steps to take to make a great storyboard for a web site design. It is important to bring your ideas even if you think they are not that good. Next you need to draw them out on paper; One paper is faster and you can always toss it away if it doesn’t look the way you want. Additionally it is good to use paper because on paper anyone can add to the design and you do not have to have a lot of experience making web sites. After drawing it out next is to find a focus from those drawings to make sure that each part of the website is completed. Following, take notes to see if there is any- thing that needs to be added. After that take the drawings that are completed and put them in a mind map to see the website more visually. Then critique the storyboard and make adjustments to the design. It is also important that other people look at it as well so you can various opinions on the storyboard.[25] When the storyboard is all finished make sure that the navigation, site structure, and content are done well. For navigation it is important to have ev- erything at least a click away, at the maximum it should be 3.For site structure check if it is too complex and that there are visuals, glossary, table of contents, and or an in- dex. The content should be understandable, creative, and flow together.[26]
Navigational Design Considerations
Braille Display
While creating a Web site, it is important not to over- look small details. The structure of the site is the most significant part for easy navigation. Headlines and main menus need to be organized in a way that is understand- able for users. Many experts and Internet users agree that it should only take up to three mouse clicks to return back to the main page and to search more easily. Different forms that are used in Web sites include search boxes, drop-down menus, site maps, text-based hyperlinks, nav- igation bars, and menu tabs. Images can also be another hyperlink to transfer to another page on the site. It is crucial that the Web site has the same links in the same location as the previous page. Things would get confus- ing if the user had to look over each navigation button
every time they entered a new area on the site. Long Web pages should be separated into shorter, more con- cise pages to avoid loading and scrolling. On many Web- sites today users will see “Back to Top” to navigate back to the top of the page, mostly on long Web pages. Most importantly, a link to the Home Page should be listed on every Web page according to the Web site.[27]
Access Considerations
Device Compatibility and Assistive Technology should be taken into consideration while creating a multime- dia Web site. As our society grows with more ways to reach the Internet than just the computer, Web site cre- ators need to be aware of the fact that the public is us- ing their Web sites on Smartphones, Tablets, iPads, and much more. The layout may be different on these smaller devices than would a desktop computer. Sites are now creating multiple ways to work with any form of technol- ogy. With stricter disability laws being put into place, we have started to think about different ways to inform the physically disabled via the Internet on Web sites. Braille display [28] and screen readers [29] are just some of the newly advanced technology that can be used. Alternative text [30] can be used, which is a text description for a web page image. These text descriptions of images are valu- able for vision impaired users of the web site.
Refreshable Braille Display
Refreshable Braille Displays are an electronic device, connected to a computer via a serial or USB cable, which uses small metal or plastic pins that move up and down to display braille characters so a blind person can read what is displayed visually on the computer.[31] The “re- freshable” quality means that the braille display is con- stantly changing as the user scrolls the mouse around the web page or document. The user can move the mouse around by through either the command keys or cursor routing keys located on the device, or through Windows and screen reader commands.[32] Typically screen read- ing software, or just a screen reader, is used in conjunc- tion with a digital braille display to give the ultimate expe- rience for people with vision loss. A screen reader trans- lates information on a web site into electronic text, which
140 CHAPTER 5. BUSINESS ON THE WEB
is sent to a speech synthesizer (so output is heard audibly) or to the refreshable braille display. The only thing that the screen reader cannot read is graphics; this is why it is important to include descriptions of pictures and “hover- over” captions when designing a web page to be sensitive to those with vision disabilities.[33] While some may only need the speech synthesizer, most prefer to have the re- freshable braille display because it provides direct access to information and thus increases efficiency in completing tasks; allows the user to check spelling, grammar, and for- matting of their own input and is quiet, so it can be used anywhere without it be being disturbing to others. Refre- shable Braille Displays come in 40, 70, and 80 character displays and can range from $3,500 to $15,000 depend- ing on the character display.[34]
5.1.4 Creating a Web Site using HTML, XML, XHTML, CSSs
HTML
HTML or Hypertext Markup Language is mostly used to create webpages. HTML is a code made up of small pieces called tags. Tags are small pieces of the HTML code that give commands to the computer on how to for- mat whatever it is linked to. tags begin with a less than symbol (<), then the command is written, then closed with a greater than symbol (>). That is the beginning tag. Next the text it applies to is inserted. Then, the tag is ended with a less than symbol (<), followed by a com- mon slash (/), then the same command code as it began with, then a greater than symbol (>). So, your basic code will look something like this: </(insert code)> Applied Text Here </(insert code)> . There are so many different things you can do with HTML. You can highlight text (even in different colors), you can make text different colors, you can (Hover Mouse Here), as well as bold face or italicize text. These are just some of the basic modifications that can be created by using HTML formatting.There are even ways to insert images as well hyperlinks. Here I have inserted A Link to Our Wikibook Homepage and even the pictures you see to the right. The possibilities are almost endless when using HTML. The biggest problem with HTML is that most people do not want to take the time to sit down and learn all of the lit- tle codes and specifications. It is very useful when trying to organize webpages once it is mastered. HTML allows users the ability to manage where images, videos, ani- mations, and text formatting are all located. It is a very powerful and useful design tool and something that seems to be somewhat overlooked and taken for granted. The newest version of HTML is HTML5, which is being created to replace both HTML and XHTML. HTML5 is designed to be simpler and many things have changed or added to the coding for HTML5. The DOCTYPE
<!Doctype HTML> <html> <head>
<meta charset=utf-8> <title>HTML5 example</title>
</head> <body>
Text </body>
</html>
1 2 3 4 5 6 7 8 9
10
HTML5 source code
and character encoding declarations have both changed to be simpler to code. Along with new declarations have come new elements for semantics, controls, graphics, and multimedia because more and more websites are becom- ing more complex with more information being packed into a website. Some of the new semantic elements in- clude <header> and <footer>, which make it easier for a web designer to indicate where a new page will begin and end. New controls for HTML5 markup language in- clude the date, time, and a calendar to help users be more aware. The biggest addition for HTML5 is the <audio> and <video> multimedia elements, because a multitude of users love to be able to listen or watch something that is useful on the website. This is especially true for e- commerce websites because potential buyers would like to be able to see a product in use, which can be shown through a video. All in all, HTML5 is a newer markup language that simplifies the coding for web designers and also makes their websites more appealing to look at.[36]
A Brief History Of CSS
The way CSS and HTML work together is very much like a Mr. Potato Head toy. The content of the web page using HTML is the potato itself, whereas the stylish customization using CSS is the collection of items that personalize your potato.
To make your website truly stand out, it needs a sense of style greater than what HTML and its ilk can pro- vide. This is where CSSs come into play. CSSs stand for Cascading Style Sheets, and they offer a way to not only specifically style a Web page but even the entire
5.1. MULTIMEDIA 141
Web site to which it belongs. Before CSSs there had been individuals who created style sheets for their own purposes but thought it unnecessary to publish their de- veloped syntax, believing that each browser should de- cide how best to display pages to its users. When Web page writers issued complaints that they couldn't cus- tomize more deeply, they were generally ignored, forced to deal with browsers that offered consistently fewer op- tions for the sake of streamlining. To address this, a Norwegian by the name of Hakon Wium Lie offered a first draft of Cascading HTML Style Sheets in 1994. He couldn't have imagined how popular his development would become.[37] CSSs offer plenty of room for style without being needlessly complicated like some of its ri- val setups, such as DSSSL. The easiest way to describe what makes CCS stand out as a language is how it works to separate the content of a page from its display.[38] CSS3 is the most popular variation of CSS right now, but num- ber 4 is already growing in notoriety.
XML and XHTML
A part of a Webpage written in XHTML.
Similar, yet very different than HTML, another type of markup language is called Extensible Markup Language, a universal format for structured documents and data on the Web. The biggest difference between the two markup languages is the fact that HTML describes presentation, whereas XML describes content. Simply, HTML de- scribes the actual content such as text and graphic images, but only in terms of how it is to be displayed and inter- acted with. On the other hand, XML describes the con- tent in terms of what data is being described. To do so, XML tags are then assigned to pieces of data. Once the data is tagged, it can be used with any XML document. XML is called “extensible” because the data contained in XML documents can be extracted and used whenever needed. [39]
Another version of HTML that is based on XML is known as the Extensible Hypertext Markup Language, or XHTML. It combines the flexibility of HTML with the extensibility of XML. This language is used to create Web pages while also supporting XML, unlike HTML. This way, XML controls the actual content displayed, while XHTML controls the appearance and format of
the Web page. However, one major difference between XHTML tags and HTML tags is the fact that there are stricter rules about how the markup tags are written. For example, unlike HTML, while using XHTML, all tags must be written in lowercase letter, every tag must have an end tag, and quotation marks are required for values. [40]
XML vs XHTML
[41]
AJAX
Conventionel modell of a web application Ajax model of a web application
cl ie
nt p
la tfo
rm in
te rn
et /in
tr an
et se
rv er
p la
tfo rm
HTTP(S) - traffic HTTP(S) traffic
user interface
web browser
server-based system
database, data handling,
legacy system etc.
web server
HTTP-request
HTML+ CSS data
web browser
user interface
"Ajax engine" (javascript)
javascript call HTML+
CSS data
server-based system
database, data handling,
legacy system etc.
web server and/or XML server
HTTP-request
XML or HTML or javascript data
Ajax-vergleich-en
Many modern websites use a technology called AJAX, for fast and effective interaction with the visitor. AJAX has become a very popular method to retrieve data from the server in the background and the Dynamic Update page. AJAX stands for “Asynchronous JavaScript And XML”. Developing code to JavaScript for AJAX imple- mentation from scratch is very time consuming and te- dious process. However, many libraries JavaScript, in- cluding jQuery, have excellent high-level AJAX imple- mentation as a set of methods and functions that make it easier and faster to build web sites. AJAX is a develop- ment technique for Web applications in which JavaScript code in the visitor’s browser communicates with the web server asynchronously, i.e. in the background. When you click links or forms contained on Convectional Web page a request is being sent to a new URL on the web server. The server sends a completely new page of HTML, which a browser displays, replacing the original page. When us- ing technology AJAX, JavaScript code makes a request to the URL on the server. The code may also send the data along with the request. JavaScript code then processes the response from the server, and acts accordingly. For ex- ample, the calculation can be made with the returned data
142 CHAPTER 5. BUSINESS ON THE WEB
is added or updated widget on the page, a message to the visitor to update the database on the server. Since AJAX request runs in the background, the code JavaScript (and a visitor) can continue to work with the page during query processing. The process is hidden from the visitor, who does not need to leave the page they are currently viewing time. This makes the page with AJAX is very pleasant to use. [42]
5.1.5 Multimedia Web Development (Scripting, Development Tools, Authoring Software, and Testing)
Creating the Multimedia Elements
Media
Multimedia presentation uses graphics, sound clip, video clips, and text to deliver a message to the audience. All you need is a multimedia authoring program and a com- puter in order to create a presentation. The reason in us- ing multimedia will be able to not only get the message you want to convey to the audience out but it provides a creative way in making it for the viewer. These following are types of situations that would see yourself wanting to use multimedia presentations in order to provide a cre- ative presentation. One is for projects in order to show your teacher or a classmate in a more formal setting, an- other would be a class exhibit for the library or computer lab, for a more personal use you could utilize it as a di- ary, and the last two ways would be in a slideshow format and or utilize it for a yearbook. The three C’s in mak- ing a good multimedia presentation would be keeping it Clean, being Consistent and bring Character to the pre- sentations. Next you will need to design the presentations in which make it able to be presentable and attract the at- tention of the audience. To continue, you’ll have to plan your presentation. Make an outline and make sure you understand the major topics of the presentation. Next the presenter will have to choose their media; multimedia el- ements support the main points of the presentation. Cer- tain data will benefit the presentation as well, like, charts, graphs, maps, images and videos. Afterwards, review re- vise and rearrange so you know that the information is accurate and ready to be presented.
Creating the web Site
Web site developers use a number of tools to create web sites. These can be divided into three large groups:
Python is a programming language used in web design
markup languages, scripting languages, and web site au- thoring software. Markup languages are the founda- tion; they are coding systems that create the overall struc- ture/appearance of the web page by the use of tags. Tags are commands that allow the web page designer to arrange text and multimedia. HTML, or Hypertext Markup Lan- guage, is the dominant markup language used today. The current version is HTML5, and it is intended to replace both HTML and XHTML, another markup language. Scripting languages allow the developer to create in- structions, or scripts, that run in the code of the web page. One example of a very popular scripting language used today is Javascript. Scripting languages are found everywhere.[43] For example, Ajax technology is found in the widely-used services Google Maps and Gmail. When used in combination with markup languages, scripting languages can enable developers to implement a wide- range of features and content into their web pages.
Adobe Dreamweaver
Web site authoring software is used to make more com- plex web pages where developers can take advantage of commands that automatically generate tags and Cascad- ing Style Sheets, which are used in the look and format- ting of what was written by the markup language. This enables the developer to work in a more productive man- ner because animations, effects, backgrounds, etc. can be applied all at one time. For example, when menu options are selected, the appropriate JavaScript or other code used to add animation or interactivity is generated. Along
5.1. MULTIMEDIA 143
with this, web site authoring programs almost always have the capability to include a variety of multimedia ele- ments, like Shockwave and Flash animations, animated GIFs, video clips, and audio clips. Two of the most popu- lar web site authoring programs are Adobe Dreamweaver and Microsoft Expression web. There are a few general features of web authoring applications a designer should know. This includes WYSIWYG, which stands for What You See Is What You Get, users can click and drag vari- ous website elements to a design canvas without having to code these widgets manually. Advantages of author- ing software also include the ability to set up and use templates to ensure consistency between webpages and multi-media can be inserted into webpages. However, a disadvantage for using a web site authoring software is that it’s not intuitive and easy to pick and use, some train- ing or technical knowledge is needed. Web sites devel- oped with these tools may not be coded efficiently, which leads to increased load times for users. Also, one needs a basic understanding of HTML. Furthermore, web site authoring software can be an expensive purchase.[44]
Weebly is a popular website builder
Website Builders are web-based tools that make it easy to create websites for small businesses or for personal purposes. One of the big advantages of using a website builder is that it no longer requires a very extensive knowl- edge of HTML. So it require minimal technical knowl- edge to create a website. Another advantage is that it is made to be user friendly. So making a website has been made to be an easier and less daunting task. An- other big advantage, especially for businesses, is that they offer mobile web design. Now that smartphones have be- come the norm. Most websites have a mobile version to them. So some website builders give responsive design to websites wherein they change when viewed on a mobile device as opposed to a computer. There are also plenty of website builders. Some may be free others may not. But mostly those that require payment also end up being the ones with the most features. A disadvantage of website builders though is that they can be expensive and while they give you a domain and an address, once you want to move your website to another host, some may not be able to thanks to a custom code they use.[45] Most web- site builders will include “What You see is what you get” builders that let you create it by dragging and dropping website elements into the content area. However, some- times it is hard to differentiate between quality website builders since some products are not up to their task (cost- ing more money or time than anticipated) but still it is a
great and easy way to set up one’s “virtual storefront”. [46]
Other Content Development Tools
ActiveX
ActiveX is a component of the software in Microsoft’s Windows operating system. Many of Windows’ appli- cations such as Internet Explorer, Microsoft Office, and Windows Media Player use ActiveX in order to embed their functions into other applications. Microsoft Inter- net Explorer replacement browser, Microsoft Edge, will not support ActiveX, marking the end of the technology.
Testing, Publishing, and Maintaining the Site
It is extremely important, before your webpage goes out, to make sure that it is up and running and functioning at one hundred percent capability. This means that there cannot be any bugs, glitches, or error pages displayed when a user is utilizing your web page. Though this may seem easy enough, there are many different steps that one should go through to make sure their page is up to speed. Every link, icon, animation, picture, and etc., needs to be tested. Many websites like to utilize the software that is out there that will manually do these needed checks for you, however it is still important to keep an eye out personally for anything that could be raising red flags. At this point, after vigorous testing, the site should be set and ready to be published. All though the page has been suc- cessfully published, the work does not stop there. Many people like to think that they are set for the future, but these pages require constant maintenance. The publisher needs to be constantly checking to make sure everything is still running smoothly, things are still up to date, and links and animation are still functioning. With out this much needed maintenance, a site becomes difficult and outdated, and users will go out of their way to make sure that they do not use it.[47] [48]
Bandwidth Considerations
In the age of the Internet, nearly everyone is online one way or another; however, not everyone has unlimited ac- cess. There are still people who only have mobile phones that are capable of accessing the World Wide Web, but
144 CHAPTER 5. BUSINESS ON THE WEB
with data limits. When creating a website it is impor- tant to consider this.[49] When a website is created, it has individual elements that have varying sizes. For exam- ple, recently the search engine “Google” has redesigned their logo and, in turn, reduced the size of the image from 6,380 bytes (6Kb) to 305 bytes.[50] This allows people with data limits to access the website more, because ev- ery time the page is loaded, it uses less data.
Demand for Multimedia web Site Development
web Design and Development
In this day and age everything is online, everyday indi- viduals go online and they use the Internet for differ- ent purposes. There is a lot of money in the industry to make web sites. The demand for these sites is that they are intriguing, useful, and navigable to users. Companies hire web designers and web developers to create multi- media elements and create sites for the online presence of the company. As a web designer, you need to have knowledge in Photoshop, Illustrator, HTML, CSS, and JavaScript. A good web developer needs to know all the things that a web designer needs to know plus advanced programming skills. Graphic design has truly emerged as a demanding field of the economy with new technological developments in multimedia and software. As mentioned above, HTML5 and CSS3 are new coding techniques that are available for developers. Students interested in these fields should continue to study HTML and CSS.[51]
5.1.6 References [1] https://www.humblebundle.com
[2] http://www.youtube.com
[3] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013939
[4] http://www.slideshare.net/kenshin1017/ introduction-to-multimedia-4663053
[5] Understanding Computers 14 ed. by Deborah Morley & Charles Parker
[6] http://computingclass6hishamuddin.blogspot.com/2012/ 07/advantages-and-disadvantages-of-using.html
[7] http://www.nextgeninteractions.com/ virtual-and-augmented-reality/
[8] http://smallbusiness.chron.com/ 5-components-multimedia-28279.html
[9] http://graphicdesign.stackexchange.com/tags/serif/info
[10] http://www.fonts.com/content/learning/fontology/ level-2/making-type-choices/serif-v-sans-for-text
[11] http://www.slideshare.net/shortcomp/ 4-multimedia-elements-video
[12] http://www.w3schools.com/html/html_media.asp
[13] http://www.slideshare.net/azmankadir/ multimedia-element-presentation
[14] http://computer.howstuffworks.com/internet/basics/ streaming-video-and-audio.htm
[15] https://en.wikipedia.org/wiki/Alpha_compositing
[16] https://en.wikipedia.org/wiki/Graphics_Interchange_ Format
[17] https://en.wikipedia.org/wiki/Portable_Network_ Graphics
[18] http://graphicdesign.about.com/od/Definitions/g/ Jpg-Files.htm
[19] http://www.nch.com.au/acm/formats.html
[20] http://desktoppub.about.com/od/designprinciples/
[21] http://www.wikihow.com/Create-a-Free-Website
[22] http://www.edrawsoft.com/flow-chart-design.php
[23] http://designshack.net/articles/layouts/ 10-rock-solid-website-layout-examples/
[24] http://www.fastcodesign.com/1672917/ the-8-steps-to-creating-a-great-storyboard
[25] http://www.fastcodesign.com/1672917/ the-8-steps-to-creating-a-great-storyboard
[26] http://public.wsu.edu/~{}ericsson/story_bd.html
[27] http://en.wikipedia.org/wiki/Web_navigation
[28] http://en.wikipedia.org/wiki/Refresh able_braille_display
[29] http://en.wikipedia.org/wiki/Screen_reader
[30] http://en.wikipedia.org/wiki/Wikipedia:Alternative_ text_for_images
5.1. MULTIMEDIA 145
[31] http://www.afb.org/info/living-with-vision-loss/ for-job-seekers/careerconnect-virtual-worksites/ retail-worksite-for-blind-users/ refreshable-braille-display-3652/12345
[32] http://www.afb.org/ProdBrowseCatResults.asp?CatID= 43
[33] http://www.afb.org/info/screen-reading-technology/5
[34] http://www.afb.org/ProdBrowseCatResults.asp?CatID= 43
[35] http://www.compapp.dcu.ie/~{}humphrys/Notes/ Internet/index.html
[36] http://www.w3schools.com/html/html5_intro.asp
[37] http://www.w3.org/Style/LieBos2e/history/
[38] http://mashable.com/2012/10/24/css-for-dummies/
[39] http://www.w3schools.com/XML/xml_whatis.asp
[40] http://personalweb.about.com/od/basichtml/a/ 409xhtml_2.htm
[41] http://www.w3.org/standards/xml/core
[42] http://www.w3schools.com/ajax/ajax_intro.asp
[43] https://en.wikipedia.org/wiki/Scripting_language
[44] http://www.teach-ict.com/as_a2_ict_new/ocr/AS_ G061/313_standard_applications/types_software/ miniweb/pg6.htm
[45] http://www.pcmag.com/article2/0,2817,2484510,00.asp
[46] http://1stwebdesigner.com/easiest-website-builder/
[47] http://office.microsoft.com/en-us/publisher-help/ prepare-publish-and-maintain-your-publisher-web-site-HA010094760. aspx
[48] http://go.hrw.com/eolang/myomed/bringit.htm
[49] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013939
[50] http://gizmodo.com/ how-could-googles-new-logo-be-only-305-bytes-while-its-1728793790
[51] http://www.orientinfosolutions.com/articles/ multimedia-web-design.php
5.1.7 Review
In the world we live in today, we are constantly bom- barded by multimedia through billboards, signs, logos, texts, ads, emails, and our day to day web browsing. Be- low is a list of vocab from the chapter and the words gen- eral definitions. Below the list is a set of fill in the blank questions. Use the vocab list to help you fill the blanks. Some words may not be used. Then check your answers at the bottom of the page. 1) Multimedia: Integration of a variety of media.
2) Web-based Multimedia: (aka rich media) refers to multimedia of any kind located on a Web page. 3) Virtual Reality (VR): used in E-commerce to show what a product or service will look like or do in the real world. 4) Text: used to supply basic content and is important in most Web sites. 5) Images/Graphics: digital representations of pho- tographs, drawings, charts, and other visual objects. 6) GIF: (Graphics Interchange Format) used most com- monly with non-photographic images and is the standard format for Web page images. 7) PNG: (Portable Network Graphics) the responding format created in 1996 because of issues with the GIF format. 8) JPEG: (Joint Photographic Experts Group) the stan- dard format for photographs based on the Web. 9) Thumbnail Image: smaller images (similar to icons) that are linked to the full size images of larger files. 10) Java Applet: a small program in a Web page de- signed to perform a specific task from calculations to an- imations. 11) Animated GIF: a group of GIF images stored to- gether in one animated file. 12) Flash or Silverlight: Animation developing tools. 13) Audio: All types of sound (music, voice, and effects, etc). 14) Video: a continuous stream of visual information that is broken into frames when the video is recorded. 15) Web Site Design: refers to the process of planning what your Web site will look like and how it will work. 16) Flowchart: describes how things relate to one an- other. 17) Page Layout: illustrate the layout and navigational structure of a Web site. 18) Storyboard: an ordered series of sketches depicting each page or screen in an animation sequence. 19) Alternative Text: captions of images to allow those who are unable to view the images the clarification of what they are missing. 20) Web Site Development: Creating a Web site after it has been designed. 21) Markup Language: a coding system used to define the structure, layout, and general appearance of the con- tent of a Web page. 22) HTML (Hypertext Markup Language): The orig- inal Markup Language designed for creating Web pages. 23) XML (Extensible Markup Language): a set of rules for exchanging data over the Web.
146 CHAPTER 5. BUSINESS ON THE WEB
24) XHTML (Extensible Hypertext Markup Lan- guage): a version of HTML that is based on XML. 25) Cascading Style Sheets (CSSs): specifies the styles used with a Web page or an entire Web site. 26) Wireless Markup Language (WML): language based on XML that is used to create Web pages to be dis- played on WAP-enabled wireless devices (such as older mobile phones and those used in some developing coun- tries). 27) JavaScript: developed to enable Web authors to im- plement interactive Web sites. 28) AJAX: A set of Web standards designed to better handle Web page interactivity by downloading only new data from the Web server, instead of redownloading the entire Web page. 29) Web Site Authoring Software: a type of application program used to create Web pages and entire Web sites. Quick Quiz: 1. HTML, XML, and _______ are all forms of _______. 2. Multimedia (sound, video, animations, text, and im- ages) located on Web Pages is known as __________ or rich media. 3. Many sites such as https://www.youtube.com integrate _______ and _______ into their site to provide entertain- ment to viewers and/or listeners. 4. The three main types of images include ¬¬¬¬¬¬______, _______, and ______. 5. Placing pages in a ¬¬¬_____ show how they are re- lated, while using a _____ shows the order of specific animation sequences. Answers: 1. XHTML (Also Acceptable: CSS or WML); Markup Languages 2. Web-based Multimedia 3. Audio; Video 4. GIF; PNG; JPEG 5. Flowchart; Storyboard
5.2 E-Commerce
5.2.1 What is E-Commerce?
E-commerce, short for electronic-commerce, is “a term for any type of business, or commercial transaction, that involves the transfer of information across the Internet”. [1] Currently, e-commerce is mostly used via the Inter- net, but before the Internet was available, a form of elec- tronic transactions occurred over Electronic Data Inter- change (EDI). Businesses and customers used EDI by set- ting up a data link specifically reserved for commerce be- tween them. [2] In 1979, Michael Aldrich invented the concept of “teleshopping” which gave the base structure that evolved into the online shopping ability we know to- day. In 1990’s, websites like Amazon.com and Ebay.com were created. Because e-commerce is now done through
the Internet, it has made a global market-place for busi- nesses and consumers to make trades and transactions all across the world. [3] For example, businesses in Europe can ship items to customers in America, and vice versa. Just like any other technology, a user needs to know how e-commerce works and how to navigate through it. One of the basic concepts is knowing what a “shopping cart” is and how to use it. A “shopping cart” is a software that allows buyers to have a virtual chart, just like you would at a physical store, to collect multiple items and be able to buy all the items at once when you “check out”. [4] Other concepts that one should know are the advantages and disadvantages of shopping online.
Advantages of E-Commerce
For businesses, the most prominent advantages to using E-Commerce are the reduced costs associated with it, the broader customer base, the increased customer satisfac- tion, and the potentially higher sales it produces. Because E-Commerce transactions are done through a website and not a brick and mortar store, much of the overhead asso- ciated with running a retail store is reduced. The need to pay for heating, lighting, staffing, and restocking a store is practically eliminated. This results in fewer employees and smaller facilities which in turn allows for larger capi- tal gains. Usually, only a company headquarters is needed along with a few warehouses that can cover larger areas than a single retail store normally would. Also, more indi- viduals can be reached through a website rather than the small geographical area that a retail store would cover. Multiple retailers are required to cover larger geograph- ical areas, but with E-Commerce anyone anywhere can access the website at anytime! This increases the pos- sible amount of customers dramatically. Websites also allow people to shop from the comfort of their own home without having to consume time and money (gas) to view a companies products in their retail store. Plenty of times have people gone to the store for a specific item only to be disappointed that it wasn't in stock. With E-Commerce this doesn't happen. The comfort provided, the time saved, and the money saved can easily increase the sat- isfaction of the consumer. The potentially higher sales is another advantage. By using E-Commerce, a business can be open every hour of the year and accessible to ev- eryone across the globe. They're no longer limited by a geographical area or a 40 hr work week.[5]
For Consumers, the greatest advantages lie in it’s conve- nience, selection, customization, price comparison, and potential cost savings. As mentioned above, the conve- nience of shopping from home (in your underwear if you like) is very appealing to many consumers. Shopping can be done during anytime of the day or night through the use of a website and it’s no longer a necessity to rush home from work to buy an item before its store closes. A per- son can also compare the prices, quality, and features of multiple items from multiple stores. Their selection is no
5.2. E-COMMERCE 147
longer limited to the facilities closest to them, but to their attention span. Before, consumers would drive from store to store comparing these characteristics before driving back to make their final purchase. The time, effort, and expense involved in this type of comparison is nullified through E-Commerce. Many individuals want to make their purchases unique to their preferences. With the option to communicate with a company directly through their site instead of buying a pre-manufactured item on a store shelf, the ability to customize the item they are look- ing for is greatly improved. The company can take the order and payment while putting it through to the ware- house so that the final product to be shipped is tweaked to the consumer’s desire. Also, the ability to save on cost is increased for the consumer using E-Commerce. The person can compare prices to find the lowest and often the item can be shipped to their front door for less than it would normally have taken to find it in a motor vehicle. They say time is money, so if your spending less time looking for what you need then you can potentially spend more time working for what you want.[6]
Disadvantages of E-Commerce
Wikimedia Servers-0051 19
As mentioned above, there are a lot of advantages, but it is not perfect. One of these disadvantages is that those who are running the site must keep the site open 24/7 since at any point it is morning somewhere in the world. This takes money to run the servers, and takes money to pay the programmers to make the site in the first place. Also a business that is running a site should make it interest- ing by having something change, like having a daily deal like Newegg[7] or return coupons like Kohls[8], otherwise people may not return to the site. Another disadvantage is that anyone can make a website, driving competition and prices. So some sites may spend extra money on multi- media for some extra allure. There are disadvantages for consumers as well. E- commerce doesn't have the same kind of physical, per- sonal interaction that traditional commerce has, and for some consumers, the asocial experience of sitting behind a screen and clicking a virtual cart icon isn't as desirable
A typical cart icon that one might find on an e-commerce site as opposed to an actual cart in a brick-and-mortar store.
as the experience of actually getting out and pushing a cart around, even if it can be easier. E-commerce is also slower: if you purchase a good from a physical store, you have it right there that same day, but if you have to wait for shipping, it'll typically take at least several days be- fore it arrives. Also, very many goods can't be purchased online, so even to the extent that e-commerce is useful, it isn't useful in all areas or for all purchases. The fact that anyone anywhere can set up an e-commerce website is as risky for consumers as it is undesirable for businesses; some sites may be fraudulent and set up to steal info or get a consumer to waste money on faulty goods. Thus, when considering making an electronic purchase, a consumer should consider whether the convenience outweighs the artificiality, whether the goods they desire can wait and can actually be purchased online, and should take reason- able security measures to ensure that they're buying what they want.[9]
Safe Practices for E-Commerce
Using E-Commerce for anything from home shopping to online banking can be very convenient for both the con- sumer and business. However, when using E-Commerce, one must be aware of the possible disadvantages. Fraud and hacking are something everyone should be informed about. Likewise, one should also know the best ways to protect oneself or ones business against them. One tip for a business to safeguard against these things is to use a secure platform. Shawn Hess, a software manager for VoIP Supply states, “Put your e-commerce site on a plat- form that uses sophisticated object-orientated program- ming language.” Another tip for businesses to use is to use a strong SSL (Secure Socket Layer) authentication. This provides both Web and data protection. This will au-
148 CHAPTER 5. BUSINESS ON THE WEB
thenticate the identity of a business and encrypt customer data in transit which protects the company and consumer from having their financial information stolen. Another way for businesses and consumers to protect themselves in E-Commerce is by using strong passwords. A business should require the consumer to make a password consist- ing of a minimum number of characters as well as sym- bols and numbers. Using more complex passwords makes it less likely for a criminal to access the site. A business would also be able to avoid threat by layering its secu- rity. They can use firewalls to stop a cyber attack before someone is able to get into the network and gain impor- tant information. Being aware of the possibility of fraud- ulent and criminal activity and knowing ways to protect oneself from it is extremely important for both businesses and consumers, especially since E-Commerce continues to expand globally.[10]
5.2.2 E-Commerce Business Models
Four E-Commerce Business Models
Online Shop
There are four types of E-Commerce business mod- els. The four types of E-Commerce business models are B2C which stands for Business-to-Consumer, B2B which stands for Business-to-Business model, C2C which stands for Consumer-to-Consumer, and B2G which stands for Business-to-Government. When working, selling, or buying with any of these models, it is important to be familiar with what each model contains. B2C represents most of E-Commerce websites. Businesses that sell to consumers are considered B2C. Online stores and shop- ping are all examples of B2C. B2B are businesses selling products to other businesses. B2B are usually larger com- panies that are supplying a service to other businesses. For example, office max is a business that sells office
supplies to other businesses. Also, they are almost al- ways doing business over the web. C2C is a website that consumers sell to other consumers. People are brought together to sell and buy products for this model. For ex- ample, EBay is a common place for consumers to sell and buy items. B2G consists of businesses working with the government. For example, the IRS is a way for busi- nesses to pay their taxes through the web. These four E-Commerce business models are very common in this day-in-age. [11]
Business-to-Consumer
B2C
Business-to- consumer (B2C) model is a business or transactions conducted directly between a company and consumers who are the end-users of its products or ser- vices. [12]The term became popular during the dot-com boom[13] of the late 1990s. While many online B2C web- sites shut down, the companies such as Amazon.com and Priceline.com survived and became the most successful companies in the world. This model is likely familiar to most people. If a person have purchased an item online for their own use, the person e-tailed. The concept was first developed in 1979 by Michael Aldrich, an English inventor, who connected a television set to a transaction processing computer with a telephone line and coined the term “teleshopping.”[14]
Business-to-Government
A “B2G”, meaning business-to-government is a varia- tion of the term B2B, or business-to-business approach to commerce, also called e-government. It refers to busi- nesses and government agencies using the Internet to mu- tually exchange information and trade with each other more efficiently. This is prompted by government solic-
5.2. E-COMMERCE 149
itations that are accepted by businesses offering some- thing a government needs. A site specializing in B2G services may provide businesses with a single place to lo- cate tax applications and other financial forms, the abil- ity to send in payments, or request answers to specific questions. B2G may also include e-procurement services, whereby businesses understand the purchasing demands of agencies, who in turn request proposal responses. B2G generally supports the idea of a virtual workplace, or the collaboration of businesses and agencies working on a contracted project. This is done by sharing a common site to coordinate online meetings, review plans, and manage progress. This concept also incorporates the rental of on- line applications and databases designed specifically for government agencies. According to the Gartner Group, B2G revenue grew from approximately $1.5 billion in 2000 to $6.2 billion in 2005. The American Recovery and Reinvestment Act of 2009 has spurned the use of B2G. [15]
Business-to-Business
Auto-parts
Business-to-business (B2B) is a type of commerce trans- action that exists between businesses, such as those in- volving a manufacturer and wholesaler, or a wholesaler and a retailer. A typical supply chain involves multiple business to business transactions, as companies purchase components and other raw materials for use in its man- ufacturing processes.[16] An example that illustrates the business to business concept is automobile manufactur- ing such as buying tires, glass for windscreens, and rubber hoses for its vehicles.[17] B2B is also used in the context of communication where employees from different com- panies can connect and communicate with one another, such as through social media like Linkedin.com A well known business to business supplier is Grainger. Grainger is known for have a massive catalogue that con- tains almost any product a company needs, not matter if that company is clothing retain of tool manufactur- ing. Grainger’s system is unique in that their online order system and brick a mortar locations work together seam-
lessly. When you order from most online wholesale busi- ness, your order is processed and shipped from a central warehouse. This can result in high shipping costs, and order delays as the order is filled, and eventually shipped from the central warehouse. Grainger has a central ware- house where they ship from, but the also can ship from their individual brick an mortar stores, which function as satellite warehouses. Because of this system, shipping time is dramatically reduced, sometime measure in hours as opposed to days, since the order is coming from a few miles away as opposed to a few states away. Further, ship- ping is less expensive, and is some cases free because of the short distance. Also, if you want to see a product for your self, or get advise about a product, you have the op- tion of going to a Grainger store and talking to a sales person there. Grainger’s system combines the efficiency and ease of online ordering with the familiarity of the physical store. [18]
Grainger logo
Consumer-to-Consumer
Craigslist
Consumer-to-Consumer (C2C) is a type of electronic commerce in which consumers buy, sell, or trade prod- ucts and services from one another through a third party website. [19] The third party website can be either fee- based or free as long as transactions are between con- sumers. Some popular websites known for Consumer- to-Consumer transactions include Craigslist, eBay, and AutoTrader. There are many advantages of C2C e- commerce. Because business transactions are done be- tween consumers and not businesses, buyers and sell- ers do not need to account for taxes. Also, the trans- actions are done on a personal level and there are no legal obligations like companies might have. This al- lows for prices to be negotiated and sometimes barter- ing can take place. Most transactions that take place on websites like Craigslist, however, are paid for with cash, so it is difficult to return items or purchase them with credit cards. There is also a lot of safety concerns with consumer-to-consumer transactions. Because many sales are completed from people’s houses, there is a lack of privacy. Also, because the buyers may be going to some- one’s house to buy a product, there are in danger of be-
150 CHAPTER 5. BUSINESS ON THE WEB
ing kidnapped. That is why many Craigslist users suggest meeting in a public area. The best part about C2C com- merce is that there are many different websites that you can use to match both the product you are selling as well as the way you would like to sell it. If you don’t want to have someone coming to your house through Craigslist, then you can simply sell your item through eBay and ship it to another consumer. It is all about putting more power into the consumer’s hands. [20]
5.2.3 E-Commerce Web Sites
Shopping Cart
Ecommerce began to gain traction in the early nineties and has grown rapidly ever since.[21] Ecommerce offers many advantages over traditional brick and mortar stores. Consumers can easily search for the products and services they are looking for. Online retailers, or e-tailers, are in- credibly convenient, in that they are available twenty four hours a day. Today, most brick and mortar retailers also have an ecommerce option. While an ecommerce con- sumer does not get the immediate gratification of having their purchase immediately in hand, they can place orders from the comfort of their own home without having to deal with the hustle and bustle of a shopping mall. Some stores offer a combination, allowing a customer to order their merchandise online, and pick it up almost immedi- ately at their local store. E-tailer sites like Amazon.com paved the way for many others. Amazon.com is arguably one of the most successful e-tailer sites around. It began as an online bookstore with a primary focus on the cus- tomer experience. It was so successful that it did not take long before it expanded beyond the sale of books. To- day, you can order almost anything from Amazon. They have also crossed over from strictly being an e-tailer to an e-tailer and subscription site with its Amazon Prime offering.
An example of a manufacturer site
Manufacturer and E-Tailer Sites
Manufacturer and E-tailer sites are basically just compa- nies that can sell their product directly to their customers via a website. [22] They are just online stores. Most web- sites like this have an online catalog of their products for the consumer to look at and choose their desired product. Then if the product is shipped to the home there is a ship- ping fee, or some products like music or books can just be directly downloaded. This would include websites like amazon.com, charlotterusse.com, or walmart.com.
Subscription Sites
An example of a subscription site
Subscription sites are an online product that a consumer purchases and pays periodically and then receives the product periodically via the Internet. An example would be Netflix, which is a monthly fee and then you can re- ceive streaming of movies or TV shows through the In- ternet. Some sites are considered subscription sites even if they don’t require a monthly fee. They may just require you to subscribe to their site to receive all the information provided. [23]
One of the the most popular types of subscription e- commerce is video-on-demand (VOD) and audio-video- on-demand (AVOD). These subscriptions allow a con- sumer to access video and audio whenever they want. Some popular examples of subscription e-commerce are Netflix, Hulu, Pandora, and Spotify. While Netflix and Hulu allow a user to access movies or TV shows, Pan- dora and Spotify allow users to access countless amounts of streamed audio. The biggest benefit a subscription of- fers to a consumer is that the consumer no longer needs to wait for specific broadcast times in order to watch or listen to a program. Sometimes airlines take advantage of subscriptions in order to please their customers dur- ing long flights. The airlines that support VOD will often
5.2. E-COMMERCE 151
Spotify, which is an AVOD subscription service
have a small screen on the backsides of headrests. This in-flight entertainment system usually allows each indi- vidual passenger to select various cartoons, TV shows, and movies. Airlines that support AVOD will often have an embedded unit in armrests. This unit usually allows a passenger to listen to various music channels.[24] In the past few years the online subscription market has taken off. Companies like HBO and Amazon have created their own VOD services. HBO’s VOD service is called HBO Instant and has become popular in 2014. Amazon’s VOD service is called Amazon Prime and is believed to have inspired the Amazon Fire TV.[25]
Brokerage Sites
Online Auction Site example
A Brokerage Site is used to bring sellers and buyers to- gether to simplify transactions between the two. The site earns revenue as a form of commission for every sale it incurs. Online auction sites are examples of brokerage sites, in that they enable consumers to buy and sell goods and services to one another. The site acts as a median be-
tween the two. One clear example of this is eBay. Busi- ness online auction sites are online auctions sites that are mostly for business transactions. An automatic bidding system is used by eBay so that consumers can easily keep up with the bidding process if he or she wishes to make a bid on a specific item. There are rules put in place so that every bidder is treated the same. A dynamic pricing site can be used instead of online auction sites. Priceline.com is an example of how this works: buyers are allowed to bid on items for sale, and the seller can then make the final decision of who shall receive the item. Financial brokerage sites are also used between buyers and sellers for stock, bonds, opinions, and more. These sites earn money by charging for each transaction. Real estate and travel are other types of brokerage sites. A market ex- change site matches organizations with different goods or services to sell with buyers and to help the buyers look for specific items that the suppliers can provide.Commodity exchanges are sometimes used when dealing with natural resources and raw goods.
5.2.4 Implementing E-Commerce
Business Models & E-Commerce Applications
Like this smiling tech support worker, you need to be both inno- vative and eager to please if you hope to get your online business off the ground.
If you're a business owner living in today’s technological age, your eye is surely on expansion through e-commerce. Whether you are the owner in question who is tech-savvy enough to build your own site, or a third-party Web page developer, there are 5 rough steps to keep in mind to en- sure the success of your e-commerce endeavors. The first of these steps is to just figure out what your web- site hopes to accomplish. You can either pick one model (such as B2B, or Business to Business) or combine a few
152 CHAPTER 5. BUSINESS ON THE WEB
Credit-cards
EBay former logo
of them depending on your ambition and the needs of your business. Within this model, you also need to be making decisions such as whether your site will be taking a Storefront approach (basically being an online version of a physical store) a Subscription approach (where cus- tomers pay for premium content that is web-only), or even Affiliate Marketing (where your business would sell the products of another business for a commission).[26] As you browse the Web and study the models of your com- petitors you'll get a good idea about what is and isn't the goal of the e-commerce site you're creating.A business to consumer model is just selling straight to the consumer. E-bay is a good example of a consumer to consumer busi- ness model. Consumer to consumer is really convenient since it always the buyer to pay the owner on the spot, not tax, no driving, etc. It is also nice for collector items that are hard to find. Anyone can go on this website to be able to sell and buy items. It is just an online auction and is also worldwide. E-bay is not free though, a user has to pay an invoice fee if they sold or listed anything. [27] The last business model is to have business to government. These businesses usually already have a previously drawn con- tract with the government because they have something that the government needs. An example of a business to government is actually being able to pay fees online. If a business has a fee to pay they can just go online and pay it off. It is also more convenient to have fees available to pay online because the use of mail is declining. Before the use of these government websites a person would have to send in the mail of have to go somewhere to pay it off. The next important step is deciding on the applications of
your e-commerce page. If you're a business owner cre- ating a Web page, it’s a given that one part of your site will be online selling, but there are ways you can establish the name of your company that go above and beyond so your customers will remember you in a positive light and keep coming back, hopefully with their friends and fam- ily in tow. These extra features are called e-commerce applications and they can range from merely providing in-depth product information to providing technical sup- port, or even letting them track online purchases through the mail. For the adventurous and creative developers, you can program games, surveys, and even music, all for the sake of providing a more intriguing online shopping experience.[28]
After selecting the appropriate business model and type of Web site along with the desired e-commerce applica- tion, another valuable procedure to consider is the proce- dures for handling electronic financial transactions. The kind of payment type an e-commerce Web site uses de- pends on the type of site it is and the types of customers involved. The available payment options will usually be displayed on the checkout page of the Web site. Nowa- days, credit card processing is the most used payment op- tion. A business needs to open an e-commerce merchant account (a.k.a. an Internet merchant account) in order to accept credit cards. A bank is hired by the merchant to monitor the transactions with credit and debit cards and usually charges a monthly fee, a transaction fee, and a commission for this service. Customers are also able to use single-use virtual credit card numbers, which they re- quest by logging onto their credit or debit card account. A virtual credit card number can be used to purchase an item online so that hackers cannot intercept the actual ac- count number during the transition. Smart cards are also becoming increasing popular. A smart card is a credit or debit card that is embedded with a computer chip. The chip usually contains identifying data for authentication purposes. Other customers online may use PayPal, digi- tal gift certificates, gift cards, and digital wallets. [29]
E-Сommerce center logo
Navigation Through a Web-based E-Commerce For customer satisfaction, the ability for them to find their way around to the products and information they need is very important. If something takes too many clicks to find then businesses start to lose customers due to their inability to change with the pace of technology. With the steps to implement Web-based E-Commerce cover- ing different ways to successfully please consumers, sto-
5.2. E-COMMERCE 153
ryboards, flowcharts, etc., can be used to improve navi- gation through E-Commerce Web-sites. Making “parent categories” that have more depth is an effective way to in- crease consumer satisfaction when browsing. Drop down menus that have many options make it so people do not have to guess where their product/service will be located, but instead have the actual category listed out for them along with many others. Along with this, sub categories should be put in appropriate places to separate the op- tions as well. Another interesting navigation tool is the ability for users to see “what’s new” on the business’ web page. With this available, new products can increase their popularity and in turn make the businesses more money. When users see a picture, their instinct is to click it to find information such as price or availability of colors, sizes, etc. If the link on a picture goes elsewhere, consumers will often be irritated or give up on a search. [30] All of these small methods can build up to create a better expe- rience for any user; and can boost a company’s sales.
Web Sites are very important in the E-commerce world
Now that practically everyone has a smartphone, busi- nesses should make sure that their websites have a mobile version. Otherwise, their website would not be as acces- sible to everyone who may want to do business with them on their phones. When they do make a mobile version of their website, they might as well take advantage of the fact that the consumer is using a smartphone by making use of its features such as using the phone’s camera for scan- ning credit cards or using the touch screen interface for easier interaction. They should also make it easier for the consumer to ask for help if they did not know what they were doing or how to do something. Because no matter how much you try to make a website accessible or user friendly there will be someone who will not know how to use or do something. Of course, to minimize the need for help you might as well make the website simple and organized. Otherwise, the need for help would be very necessary and that is not very good for business. Another
good tip is to add supplemental information to whatever is on your website to minimize confusion.[31]
5.2.5 Effective E-Commerce Websites
The fourth step to follow when implementing Web-based e-commerce is designing and developing an effective Web site. If not the most, Web site design and develop- ment are definitely a few of the main features that have to be straight on-point to gain, or manage existing cus- tomer support. Whereas Web site design is the process of planning what a Web site will look like and how it will function, Web site development is the process of actu- ally building the Web site, testing it out, and publishing it on the Internet for public use. Without obstructing the site’s usability, a Web site creator’s ultimate goal is for the Web site to be balanced equally between its attractiveness and user friendliness, while still providing 100% security. Therefore, in addition to perfect design and development, e-commerce sites also have to ensure that order forms and checkout pages are located on a secure Web server, to avoid any potential security threat. With that step comes another responsibility of continually evaluating the secu- rity of the Web site and any collected sensitive data to ensure that the customer, or the user’s, security and pri- vacy are being taken care of diligently. Lastly, all of the previously mentioned e-commerce features can be cre- ated using two types of software: Storefront software and Shopping Cart software. The storefront software facili- tates the creation of an online store; while on the other hand, the shopping cart software is designed to add only the ordering and checkout capabilities to an existing Web site. [32]
E-commerce is something we are bombarded with on a daily basis. Any time that we go to the internet we are almost guaranteed to see an ad or access some kind of site that is selling something to consumers. Whether or not we choose to click and access these sites is another story. Although, when we do, there are a few things that these sites can take advantage of to try to ensure user pur- chases are made. Firstly, these sites are going to want to look appealing to the group they are advertising to (e.g. a website selling kids toys would want to be colorful and full of pictures not just plain black and white text with limited images). Next, it is important that the website be user friendly. This involves: easy navigation, pages load- ing in a timely manner, and having some special perks like a search box or a dropdown of links to all the main pages on the site. While these are not necessary things to create a website, they are useful things for websites to contain in order to satisfy visitors. Other helpful, but not necessary, things to include are contact information, spe- cial promotions, and even social media links so customers can share about their experience with the site[33]. In the realm of E-commerce, there are two things that are very important: the shopping cart and security when processing transactions. Have you ever bought (or tried
154 CHAPTER 5. BUSINESS ON THE WEB
to buy) something from a site and had a hard time find- ing the shopping cart? Or have you had trouble editing the items in your shopping cart? These problems are big E-commerce no-no’s and something most sites do try to avoid. However, they do still happen. The shopping cart is something that, ideally, would be accessible and easy to find from any page on a website, and once you are look- ing at the items in your cart, it should be simple to mod- ify the items (add or delete products). Another thing that E-commerce sites should do is ensure that their check- out page is in fact secure. When purchases are made on- line, most people use their credit/debit cards to pay for their items. With the number of people in the world who know how to hack computer systems or decrypt code, it is important that websites ensure the security of such im- portant personal information. Without this security there would be virtually no way to protect yourself from credit fraud or identity theft. While there are still ways for peo- ple to access the information, it is much harder to access it from a secured site. There are a few ways to check a sites security including the “http://" section of a URL being green in color, the URL beginning with “https” in- stead of just “http”, as well as the security certificates that most secure sites will post on their pages to advertise their security to their customers.
5.2.6 E-Commerce Sales and Marketing Strategies
Click Fraud
Click Fraud
Click fraud is an illegal practice that occurs when individ- uals click on the Web site’s advertisements in order to in- creases the number of click through to the advertiser. The individuals who use click fraud use it in order to increase their own personal banner ad revenues and also by compa- nies who use click fraud as a way to deplete a competitor’s advertising budget. Click fraud was once known to be a very large problem within paid searches in which Google was first introduces with the invalid click to be known as a metric. A metric was intended to provide some in- sight into how much fraud was occurring and ease the minds of advertisers. Google identifies three areas they determine to be invalid clicks: Manual clicks intended to increase your advertising costs or to increase profits for website owners hosting your ads, Clicks by automated clicking tools, robots, or other deceptive software, Extra- neous clicks that provide no value to the advertiser, such as the second click of a double-click. The difference be-
tween then and now and the source of the invalid clicks of today. Click fraud still occurs in paid search, and at some level always will. However, the engines at this point do a solid job at monitoring the problem. The issue for search marketers is to ensure the metrics don't go out of whack from a normal level of variance. Meanwhile the focus will be on emerging media types where fraud is ahead of the development curve.[34]
Procedures for Handling Electronic Financial Trans- actions
Learn to do it safely
There are different ways an e-commerce site can set up payment options, and it is important to understand what type of payment option is best for the nature of the site. Credit cards, debit cards, PayPal, Bill Me Later, and gift cards are the most common payment options used by e- commerce sites. Payment by credit/debit card is the dom- inant method. Businesses usually open an e-commerce merchant account to allow for these payments. For pay- ment with credit, a buyer makes a transaction with the credit card where money is then transferred from the credit credit card company to the merchant account. For debit cards, money is simply taken from the checking account and transferred to the merchant account. Busi- nesses pay fees to the banks for this service. A relatively new system is for consumers to use low-cost card-swipe devices that enable merchants to get by the higher rates when the card is not physically present. Airline and travel sites are some businesses currently taking advantage of this method. Virtual account numbers, smart cards and prepaid credit cards are all used to better improve the security and safety of both the transaction process and the account informa- tion of the card holder. These cards can be secured with a PIN and/or a one-time password (OTP) to decrease the
5.2. E-COMMERCE 155
chances of a hacker obtaining account information. Online payment services, like PayPal, and the use of gift cards, coupons and digital gift certificates are two other popular payment options. PayPal allows individuals to transfer money from their online payment account to an- other, and it is the prefered payment method for trans- actions on Ebay.[35] This type of service is prefered be- cause it does not require consumers to reveal their credit card numbers to the merchants, and merchants pay lower fees than conventional credit and debit card purchases. Lastly, gift cards, coupons, and digital gift certificates al- low gift recipients to select their own items at an online store. These can be purchased in physical or digital form where the codes are then entered in the checkout process. Also, coupons are becoming much more popular with the increasing use of mobile phones.
Physical Credit-cards
Virtual account numbers work the same as the number on the actual card. However, they are used with limits set by the user within a certain time frame. The primary use of this virtual account number is to enable users a safer way to use a single credit card for purchases by using a tempo- rary account number. The code is a typical 16- digit code. Users claim that this option takes around 60 seconds to set up. The way a user can set up these virtual account numbers is very simple. First, a user must log-in to their credit card account, navigate through a few boxes, and set the expiration date. Although the concept of virtual ac- count numbers is not new, they are becoming more popu- lar today. Especially with the expansion of smart phones. The actual account number is not a physical card, and it is primarily used for online transitions. With security becoming an increasing primary factor for users to con- sider, virtual account numbers seem very handy. Many consumers choose to shop online. With the use of vir- tual account numbers, users can be assured security from the first payment they make. The set time limit makes it very convenient to fit the consumer’s needs. Overall, with such effective security features, it is a surprise that virtual account numbers are not used as often. [36]
Bitcoins
Global Bitcoin
Bitcoin is a new cryptocurrency, which created by an unknown programmer (or a group of programmers) un- der the pseudonym Satoci Nakamoto. This happened in 2009. Nobody knows where this man is and what his name is in the real world. Cryptocurrency Bitcoin has the basic functions and properties of conventional money from different countries. It could exchange, stored and used to purchase. However, Bitcoin is cryptocurrency, which is a type of digital currency. Its emissions and ac- counting based on different cryptographic methods. A decentralized operation occurs, in a distributed computer network. Cryptocurrency - this is the real software, the growth rate of which depends on supply and demand, not by subsequent investors. Each member of the network can make instant transactions cryptocurrency without in- termediaries. That is, the buyer sends the money directly to the seller. No need to go to the bank, you simply send Bitcoins to the person. Coins in the system are the cryp- tographic (mathematical) hash functions. Each of them is completely unique and cannot be used twice. Bitcoin can be used to purchase goods and services on the Inter- net anonymously. Moreover, it is easier and cheaper to make international payments because Bitcoin is not tied to a particular country. To store Bitcoins have a few op- tions. Offline purse is being installed and is created on your PC. Usually, it is encrypted to prevent tampering. But, there are some cons, if you forget the password to log into a purse or on your computer hard drive died you lost your money. Online Bitcoin wallet has advantages over the offline version. You can access it using not only PCs but also tablet or phone. One of the main problems of these wallets is that all the data stored on the server. Many online stores or retail outlets that accept bitcoin currency side by side with local currency, debit cards or credit cards, opens the window of opportunity for users to compare the benefits of shopping via bitcoin payment.
156 CHAPTER 5. BUSINESS ON THE WEB
[37]
Driving Business through Meta Tags
Drive your search engine business through meta tags!
Keeping and maintain your company’s website is very im- portant in working towards driving business. Many of us, when we search the Internet, are not just going directly to one specific page. We want to browse and find what pages pull up for the topic in which we are searching for. That is why most of us use search engines such as Google, Ya- hoo, etc. The problem is, you need to make sure that your getting business and traffic from these searches. Most of the time, people don’t make it past the second page of results to find what they are looking for, so what does a company need to do to make its page relevant? They use meta tags, which are essentially labels that search engines such as Google and Bing can use to find web sites related to search terms. For example, a hair salon’s website would likely include meta tags such as haircuts, hairstyles, and other related terms. Good website design includes many variations of meta tags, to increase search matches. This is crucial to making sure that the page is getting the traffic that it needs to drive business. [38]
Anticybersquatting Consumer Protection Act
Domain names are unique and are registered through an official domain name registrar. This forces businesses to come up with a very unique website domain name that will only attract their customers. Some people try to reg- ister domain names in the hopes of stealing profit from a company or another person, but this is actually illegal. The Anticybersquatting Consumer Protection Act pro- tects businesses trademarks in cyberspace, by making it illegal for others to create a confusingly similar domain name with the intent to profit off the trademark without regards to the goods or services of the original trademark owner. This can be related to the recent news of Johnny Manziel’s friend trying to trademark “Johnny Football” in the hopes of profiting off of Johnny Manziel’s legacy. The only difference is that the ACPA affects online do- main names instead of the actual trademark. There are
Trademark symbol
many factors that are considered when a domain name is registered. This includes if the domain name is the legal or nickname of the registrant, if the registrant has a trade- mark of the same name, if the intent of the website is to harm the trademark owner’s good will, if the registrant resells the domain name without having ever used it for the sell of goods or services, and multiple more factors. All of this has come into fruition to help protect trade- mark owners from being scammed out of their rightful profit and to stop people of ill will from buying a wrong- ful domain name. [39]
Search Engine Optimization
Getting to the top of Google results is important.
Search site optimization is one way that a website can make themselves more easily found online when being searched for through search engine websites like Google. Typically, the most popular website with the most rele- vant information based on the searched keywords is dis- played as the top result. To optimize a website, one can edit the content of the website itself and the HTML code so that when the search engine is crawling through its database that page is determined to be more relevant. An- other way of optimizing a website is through increasing the amount of backlinks, or incoming weblinks that lead to that page. The more back links that a website has, the more popular the website is to the search engine. In the
5.2. E-COMMERCE 157
modern world, search engine optimization is a huge deal for any businesses that are trying to promote themselves on the internet. Regardless of the size and content of a website, proper search engine optimization can get any web page to the top of the search results, which would therefore increase the overall visits to that site. [40] Most users of search engines do not look much farther than the first few results or the first page, making it crucial for any company trying to break into the business and beat the competition to be amongst those results. [41]
Advertisement Strategies
A banner ad
Business’ employ several online advertisement strategies in order to appeal to the consumer. A popular method of displaying a product or to promote a business is to place banner ads on popular websites. Banner ads are size-able pictures that display what the business would like it to, and when clicked on, the ad will link the user to the busi- ness’ page. While banner ads used to be static ads, today it is much more popular to use dynamic banner ads such as videos or animations. To place banner ads, typically an online advertising firm is used and the company pays a fee to each Web site on which the ad is displayed, as well as a fee to the advertising company. Another adver- tisement strategy is the use of behavioral ads, which are ads that are targeted to individuals based on their pref- erences, buying habits, or interests. These preferences are usually determined by cookies places in participating Web sites by advertising networks. The data that behav- ioral advertising collect about the consumer is not tied to personal information, but rather online activity. Exam- ples of what a behavioral ad tries to find out about the consumer includes the consumers age, gender, and pur- chase interests.[42]
5.2.7 Review
brick-and-mortar store A conventional store with a physical presence. brokerage site A type of Web site that brings buyers and sellers together to facilitate transactions between them; the site earns revenue in the form of commissions on sales made via the site. digital wallet A program or online service that holds a buyer’s information (such as electronic payment, billing,
and shipping information) that can be used to speed up online purchase transactions. dot-com An Internet-only store with no physical pres- ence. e-commerce The act of doing business transactions over the Internet or similar technology. meta tag A special HTML or XHTML tag containing information about a Web page that is added by the person creating the Web page and is used primarily by search sites. online auction site A Web site where potential buyers bid on an item and, at the end of a set time period, the highest bidder buys the item as long as all bidding criteria (such as minimum selling price) have been met. online payment service A type of payment service ac- cessed via the Internet and used to make electronic pay- ments to others, such as via deposited funds, a bank ac- count, or a credit card. search site optimization (SSO) The process of evaluat- ing a Web site and making changes to improve search site results. shopping cart software E-commerce software designed to add ordering capabilities to an existing Web site. storefront software E-commerce software that facili- tates the creation of an online store. subscription site A site that sells access to its online con- tent.
5.2.8 Review Questions
1. What is the process of evaluating a web site to improve the search site results? 2. What is a program that holds a buyer’s information? 3. What is a type of Web site that brings buyers and sellers together to facilitate transactions between them? 4. What is a special HTML tag containing information about a Web page? 5. What is a web site where potential buyers bid on an item? 6. What is a type of payment service accessed via the Internet which are made to make electronic payments to others? 7. What is E-commerce software that facilitates the cre- ation of an online store? 8. What is a site that sells access to its online content? 9. What is a type of Web site that brings buyers and sellers together to facilitate transactions between them? 10. What is a conventional store with a physical presence? Answers: 1. search site optimization 2. digital wallet 3.
158 CHAPTER 5. BUSINESS ON THE WEB
brokerage site 4. meta tag 5. online auction site 6. online payment service 7. storefront software 8. subscription site 9. brokerage site 10. brick-and-mortar store
5.2.9 References [1] http://www.networksolutions.com/education/
what-is-ecommerce/
[2] http://www.networksolutions.com/education/ what-is-ecommerce/
[3] http://blog.templatemonster.com/2010/09/08/ history-of-ecommerce-timeline-infographic/
[4] http://www.networksolutions.com/education/ what-is-ecommerce/
[5] http://forbstudents.blogspot.com/2009/05/ advantages-and-disadvantages-of-e.html
[6] http://tokokoo.com/2010/07/ advantages-and-disadvantages-of-e-commerce/
[7] http://www.newegg.com
[8] http://www.kohls.com
[9] http://ecommerce.about.com/od/eCommerce-Basics/a/ Disadvantages-Of-Ecommerce.htm
[10] http://www.pcworld.com/article/2042408/ 15-ways-to-protect-your-businesss-e-commerce-site-from-hacking-and-fraud. html
[11] http://www.ecommerce-web-hosting-guide.com/ ecommerce-business-models.html
[12] http://www.investopedia.com/terms/b/btoc.asp
[13] http://www.techopedia.com/definition/26175/ dot-com-boom
[14] http://www.businessnewsdaily.com/5085-what-is-b2c. html
[15] http://searchcio.techtarget.com/definition/B2G
[16] http://www.investopedia.com/terms/b/btob.asp
[17] http://en.wikipedia.org/wiki/Business-to-business
[18] http://www.grainger.com
[19] http://en.wikipedia.org/wiki/Consumer-to-consumer
[20] http://education-portal.com/academy/lesson/ consumer-to-consumer-c2c-e-commerce-definition-business-model-examples. html#lesson
[21] http://money.howstuffworks.com/history-e-commerce. htm
[22] http://www.thefreedictionary.com/e-tailer
[23] http://www.thefreedictionary.com/subscription
[24] https://www.princeton.edu/~{}achaney/tmve/wiki100k/ docs/Video_on_demand.html
[25] http://variety.com/2014/digital/news/ amazon-adds-hbo-series-to-prime-instant-video-including-boardwalk-empire-sopranos-1201187916/
[26] http://smallbusiness.chron.com/ types-ecommerce-business-models-2447.html
[27] http://en.wikipedia.org/wiki/EBay
[28] http://www.getelastic.com/ 7-wicked-ecommerce-applications-of-shopping-apis/
[29] http://www.sba.gov/content/online-payment-services
[30] http://www.smashingmagazine.com/2013/11/11/ guidelines-navigation-categories-ecommerce-study/
[31] http://mashable.com/2011/08/01/tips-better-website/ #Ao_hWvZO0uqS
[32] http://www.smartwebby.com/web_site_design/ webdesign_tips.asp
[33] http://www.hongkiat.com/blog/ essential-things-ecommerce-site-should-have/
[34] http://searchenginewatch.com/article/2261638/ Click-Fraud-is-a-Small-Problem-in-Search-These-Days
[35] http://pages.ebay.com/help/pay/paypal.html
[36] http://money.usnews.com/money/ personal-finance/articles/2011/09/30/ should-you-use-a-virtual-credit-card-number
[37] http://www.forbes.com/sites/johnrampton/2014/07/02/ how-bitcoin-is-changing-online-ecommerce/
[38] http://searchenginewatch.com/article/2067564/ How-To-Use-HTML-Meta-Tags
[39] http://cyber.law.harvard.edu/property00/domain/ legislation.html
[40] http://www.webopedia.com/TERM/S/SEO.html
[41] https://en.wikipedia.org/wiki/Search_engine_ optimization
[42] http://www.truste.com/consumer-privacy/about-oba/
Chapter 6
Systems
6.1 Information Systems
6.1.1 What is an Information System?
CS, Complex Problems
● Computer Science ● Software Engineering ● Information Systems ● Information Technology ● Customer CS, Applied Solutions
D is
co ve
ry
Customer Support
CS Venn Diagram
A system is a group of procedures and different elements that work together in order to complete a task. Now we can add on to this to get information systems. Informa- tion systems are much the same, there are elements and procedures to work to complete a task. The difference is information systems are used to generate information for the users on a need basis. Information systems man- age and process data as soon as they are created. They can also be used for long term planning or just the day to day work. While systems are great and can ease your life, they are static, which means someone will need to change the systems when new needs arise. This is called system development. While it could be costly, there re- ally is a need for system development since things change constantly. Whether there are new laws or a new policy within the company. Some information systems are meant to be used by all lev- els of employees while others are specifically designed to handle the needs of employees with certain respon- sibilities. As one goes higher up the company ladder, it can be seen how responsibilities may increase relative to position. It is for this reason that some information systems are designed to hone in on the needs of certain
Management Pyramid
level employees. At the ground level, employees gener- ally make job related decisions that are based on “on-the- job” input without having to consider how those decisions will effect other departments or employees in other po- sitions. These usually involve transaction systems such as point-of-sales or warehouse systems that record stock and inventory. Operational managers such as supervisors or foremen use separate information systems designed to meet short term goals and gains. They might use systems that show the productivity of employees or the cost effec- tiveness of certain changes they've made in production. Middle managers are a step up from this and use informa- tion systems that house a broader range of information to make more tactical decisions. These decisions are usually aimed at a farther sighted goal than those of Operational managers and often need more intelligence pulled from data systems in order to reach these objectives. Middle managers might be more concerned with how to improve yearly gains and may use systems that will deliver more detailed information about specific locations of factories or retailers in certain states. Executive managers think in terms of the future and the direction of a company re- lated to their peer corporations. They make very strategic decisions to ensure the survival of the entire company as a whole in relation to the economy and competition. The systems they use might include the stock market, which tracks the progress of a lot of businesses. Because the needs of each position increases, the decision support sys-
159
160 CHAPTER 6. SYSTEMS
tems needed to make well judged verdicts must increase as well.
6.1.2 Types of Information Systems
The Four Essential Information Systems
Which information system do you use the most?
Statement of cash flows can be created by accounting system
There are many different types of information systems. Even though there are many systems, the four that will be elaborated are the following: transaction processing sys- tems, customer relationship management systems, busi- ness intelligence systems, and knowledge management systems. Transaction processing systems are used for
processing and outputting functions for the core opera- tions of a business, storage, and data collection. The pur- pose of this system is to collect input and then produce the output. An online air ticket booking system is an exam- ple of a TPS. Customer relationship management systems are usually used by business owners for sales and market- ing efforts. This system helps businesses keep record of customer activities, purchasing trends, product defects, and customer inquiries. CRM systems also allow busi- ness partners to communicate with each other which con- tributes to a successful business. Business intelligence systems are essential for businesses to predict sale pat- terns for their company. BIS are essential in collecting data from different companies. Financial Institutions are an example of this type of system; it is used to create credit risk models that study the number and amount of lending given to the sectors. Knowledge management systems organize the knowledge within an organization and then share it. KMS brings innovation, top quality per- formance, integration, and knowledge to an organization. Small and large enterprises can benefit from this type of system. Business owners view this system as a valuable attribute to their company because it provides quick re- sponses to their customers and partner questions.[1]
A simplified idea of document management
Office and User Productivity Support Systems There are systems implemented in many institutions (ex. Universities, hospitals, corporations) that help users in everyday tasks including the creation of documents and other content through applications as well as communi- cation. These systems are one of the oldest and sim- ple types of systems that have been created when insti- tutions started going towards paperless solutions.[2] Doc- ument Processing Systems are support systems that allow users to create documents with the use of software and/or hardware. Often these systems include software applica- tions such as Microsoft Office or Apple iWork and hard- ware such as scanners. Document Management Systems are systems that both store and organize the documents. The goal of these types of systems is to make documents easier to find by placing them in one centralized repos- itory. A Content Management System is essentially the same as a Document Management System except that it also manages multimedia documents such as pictures or
6.1. INFORMATION SYSTEMS 161
videos rather. Although they may seem simple because we use them everyday, Document Processing and Doc- ument/Content Management Systems can be very com- plicated when taken to a larger scale because it includes not only the organization and creation of a database, but also ensuring the security of the documents within the system.[3] Another common type of Office and User Pro- ductivity Support Systems include communication sys- tems. These can be any sort of software that allows users within an institution to communicate. Common commu- nication software includes email, videoconferences, and messaging.
Transaction Processing Systems Any computer ap- plication that helps process business transactions is called a transaction processing system (TPS). Order entry sys- tems, payroll systems, and accounting systems are three main types of TPSs. Order entry systems simply record order data. For example, when purchasing an item from Wal-Mart’s website, your order is recorded by an auto- mated order entry system. The type of order entry system Walmart’s website uses is an e-commerce system due to the fact the order was made over the internet. There are also order entry systems that work with physical transac- tions, called point-of-sale systems. For instance, if some- one were to purchase a product at Wal-Mart (not online), the order would be processed at a register using a point- of-sale system. A payroll system is another type of a TPS that is used by almost every employer. Payroll sys- tems basically organize, compute, and issue paychecks. These systems automatically take out the correct amount of taxes and other deductions from an employee’s pay. Accounting systems are a type of TPS that records finan- cial transactions. Three types of widely used account- ing systems are accounts payable systems, accounts re- ceivable systems, and general ledger systems. Accounts payable systems keep track of how much a seller owes a buyer, while accounts receivable systems keep track of how much a buyer owes a consumer. General ledger sys- tems are systems capable of putting together account data to form financial reports.[4][5]
Enterprise Systems
An enterprise system is an integrated information system that is made to support business processes, information flows, reporting, and data analytics in complex organiza- tions. Its main function is to coordinate all of the ma- jor processes of an organization and integrate those pro- cesses into the different departments of the organization. Some of these application processes may include sales and distribution, financial accounting, investment man- agement, materials management, production planning, maintenance, and human resources. Because it is inte- grates, it allows data to be used for several purposes.[6] There is a central database that collects all the data from all of the applications, and then in return it feeds out
Enterprise System Modules
the data as output to all of the processes of the orga- nization. So, once data is given by one processes, then all the processes have access to that data. An example would be a university or college that uses an enterprise system to manage all student records, enrollment appli- cations and acceptance, finances, human resources, etc.[7] Many companies are starting to implement enterprise sys- tems because it is an easy way to combine the core func- tions of the company with technological advancements. It is an easy way because the enterprise system is a sin- gle software architecture that fuses all the core processes of a business to function as one unit. The synchronized functioning of the processes makes it easier and more ef- ficient to for multiple departments to work together and it is also helpful for managers as they can better oversee multiple tasks and project at one time.[8]
Enterprise Architecture Waterfall Model
Enterprise systems were created to eliminate the problem of the shattering of important information in large busi- nesses. Most companies have so much information stored in so many different areas that when information needs to be retrieved, it becomes a hassle. If a company’s infor- mation is shattered and cannot be retrieved when needed if retrieved at all, it will eventually reflect into their sales. An enterprise system is a single database which gets in- formation from all of a company’s activities. Whenever someone changes information in any area, the system will
162 CHAPTER 6. SYSTEMS
then update it throughout and make the information up to date. The amount of productivity and speed can really increase when a company begins using this system. This also gives them the ability to be organized and function on a larger level. Inside of an enterprise system there are modules. Some modules are used universally by all com- panies and other (such as human resources) are specific to each company. Configuration tables are also part of what makes an enterprise system. These are how a company can make their system unique to their business. They can change certain parts of the system such as not only hav- ing an inventory, but instead having inventory account- ing. Enterprise systems help with logic and organization in companies and provide a better “flow” in how things are run.[9]
Data Mining
Data Mining “Data mining” sounds like a kind of un- nerving term or a violation of privacy, but it isn't re- ally. It just refers to any “process of analyzing data from different perspectives and summarizing it into use- ful information”—in other words, taking a lot of data about anything, including public information, and ana- lyzing it with software to a useful end that can't easily be reached by a human alone. It’s using computers to sift through a large amount of data that a human being can't analyze. For example, supermarkets regularly have com- puters analyze massive amounts of data on which items are more or less frequently purchased in which locations so that they can stock stores with items that will be pur- chased by more individuals in that store’s location. They also might change the prices of items slightly on certain days when those items are more commonly purchased, and they stock items close to one another that are often purchased together. There are many other uses of data mining besides just these (which are examples that have actually occurred, not just hypothetical ones), but in gen- eral, data mining is most frequently used via corporations to cut costs or increase revenues.[10]
Data Mining Techniques
Because prediction is the main goal, predictive data min- ing is the most common type of data mining, with popular and practical business application. The process consists of three stages: (1) Exploration, (2) Model Building and Validation/Verification, and (3) Deployment
Stage 1: Exploration. Begins with data preparation which may involve the cleaning and transformation of data, se- lecting subsets of records, or performing preliminary fea- ture selection operations (to bring the number of variables or fields to a manageable range). It also may involve sim- ple, straightforward predictors for a regression model, in order to identify the most relevant factors and determine the complexity, and/or a general nature of models. Stage 2: Model building and validation. Involves con- sidering various models and choosing the best one based on their predictive performance (offering stable results across samples). Many techniques (Bagging, Boosting, Stacking, and Meta-Learning) developed to achieve this are based on so-called “competitive evaluation of mod- els,” which uses different models on the same data, ana- lyzing their performance, and choosing the best. Stage 3: Deployment. Using the model selected as best in the previous stage and applying it to new data in or- der to generate predictions or estimates of the expected outcome.[11]
Computer-aided design/computer-aided manufac- turing
LiftFan-F35B (CAD)
Computer-aided design/computer-aided manufacturing (CAD/CAM) are computer systems that are used to de- sign and manufacture products.[12] CAD is used to assist in the creation, modification, analysis, or optimization of a design. It is used to increase the productivity, improve the quality, improve communications through documen- tation, and to create a database for manufacturing. It is used in many applications such as automotive, ship- building, and aerospace industries, industrial and archi- tectural design, prosthetics, and many more. Also, CAD is used to produce computer animation for special effects in movies, advertising and technical manuals.[13] CAM is used to control machine tools and related machinery in the manufacturing of work pieces.CAM can also as- sist in all operations of a manufacturing plant, including
6.1. INFORMATION SYSTEMS 163
planning, management, transportation and storage. The primary purpose of CAM is to create a faster production process and components.[14] Compared to manual ma- chines, there are several advantages to using CAM such as speed (CAM is faster because machining speeds are higher), greater accuracy, greater consistency (every fin- ished product is the same), efficiency (production can run 24 hours a day, 7 days a week) and sophistication (CAM is able to machine difficult shapes, eg tracks on a circuit boards).[15] After the model is generated in CAD, it can be input into CAM software which then controls the ma- chine tool.
Decision Support Systems
A specific type of support system often used by busi- nesses is known as a decision support system. Decision support systems were originally being researched as early as the 1960’s, but began interacting with users in the mid- dle and late 1980’s. A decision support system enables a user to make decisions on demand, and interactively. These systems use both internal and external data to pro- vide a user the tools to organize the decision-making in- formation. The concept of decision-making is to primar- ily allow the user needed information to make particu- lar decisions. The system is not necessarily making the decision for a user; it is simply retrieving relevant infor- mation that will assist them in their decision. With that being said, DSS systems are primarily used to uncover unstructured information regarding issues middle and ex- ecutive managers may face. Once the data is retrieved from either internal or external sources, the system al- lows human-friendly access to retrieve the data. Exam- ples of prospective data gathered would be: inventories of information, comparative sales figures, and projective revenue. This system is indeed relatively simple to use through its interaction with the user of the system. DSS systems also allow great flexibility for the program, ap- pealing to various ranges of information. The system can also adapt to the user’s environment as well.[16]
You may not realize it, but whenever you fly on an air- line, a massive amount of data has to go through a series of programs and locations and be approved before your flight can occur. These decisions are made at an airline’s dispatch center. At a center, flight data information such as weather, weight, passenger information, and gate avail- ability are all put together and interpreted to make a safe flight. United Airlines is a good example of this. They consolidated their dispatching center to one location, the 27th floor of the Sears Tower in Chicago. Their facility takes up an entire floor of the building and brings every- thing for a flight together. A standard computer program is used to interpret all the data needed for a flight. Af- ter the dispatcher prepares a flight, the information can be transmitted directly to and airplane flight deck, or a United airport facility. The flight can then go as planned. At the same time, as dispatcher can decide to cancel a
Example of Geographic Information System
flight if the information calls for it, of if there is some kind of crisis to deal with. Because of special programs and new technology, your flight can be completed safety, and without long delays.[17]
Artificial Intelligence
Artificial Intelligence systems are systems that allow com- puters to perform actions that are characteristic of human intelligence. These can include systems such as Expert Systems, which provide the user with the kind of advice one would expect to receive from a human expert. This can help businesses make important decisions and predic- tions. There are also Neural Networks, which are systems in which the human brain recognition process is mim- icked by a computer. This can be used in medical reading or biometric identification. Another advancing technol- ogy is Robotics, or the study of robots. A robot is a de- vice that can respond to sensory input, and is controlled and programmed by human intelligence. With constant advancement in technology pertaining to Artificial Intel- ligence, one would be well advised to seek out the pos- sible effects of these “life like” computers. One person who has already studied this is a man by the name of Ray
164 CHAPTER 6. SYSTEMS
Artificial.intelligence
Kurzwell. Kurzwell is an author, inventor and a futurist who proposes the idea of technological singularity: the idea that artificial intelligence, genetics, nanotechnology and robotics will soon result in a human-machine civi- lization. He believes that in the not so near future, man and machine will merge, “allowing one to transcend bi- ological mortality.” This will be due to advancements in genetics that will allow for scientists to reprogram genes to eliminate disease and curb the aging process. With advancements in nanotechnology, the human body could be able to embody robotic red blood cells to stay healthy from the inside out. Artificial intelligence could allow for super human intelligence allowing the mind to be “backed up.” Ray Kurzwell may be a bit ahead of his time with his ideas and theories, but at the rate technology progresses in this age, it is hard to predict the heights in which it will reach. Is a human-machine race mans inevitable fu- ture? Time will tell. Learn more about Ray Kurzwell and his ideas by checking out his book, The Singularity is Near, and the documentary about him called Transcen- dent Man.[18] Morey, Deborah and Charles Parker. Un- derstanding Computers Today and Tomorrow, Compre- hensive.14 ed.
6.1.3 IBM Watson and Cognitive Comput- ing
IBM Watson is a relatively new computer system (cre- ated by IBM) that handles information processing a lit- tle bit differently than classical computers. In a classic example of computers, a query might be submitted to
IBM Watson
the computer to find, say, a name or number or infor- mation on a certain subject or idea. The computer then sifts through the table, or graph, or even the World Wide Web to find terms that match what was searched. For example, say a chef was looking for a specific method of cooking eggs. They might go onto Google an search, “Eggs Benedict”. This query would result in information about the biology of an egg, where it comes from, its importance in certain areas of the world, and then have some results about Saint Benedict, the movie “Benedic- tion”, etc. In order to find the cooking information that is sought, very precise syntax is needed, and even that might lead results astray. With the integration of cogni- tive computing (CC), the computer used by a chef would understand a query in terms of context and meaning as it relates to the circumstance. In other words, it would give recipes for different types or variations of Eggs Bene- dict from various critically acclaimed cookbooks. Cog- nitive computing allows the computer to think about in- formation its given in a critical way. This allows the com- puter to grasp complex and ambiguous ideas and nuances within the language. A huge accomplishment of these computers is their capacity to understand and interpret metaphors, similes, and idioms. Again referring to the egg example, cognitive computers will be able to under- stand that the context of the search is coming from a chef. It will also remember past searches that also had to do with food and cooking. Then, after understanding con- text and remembering past searches, it sorts through un- structured data, which is information written or created by humans, for other humans. Unstructured data includes blogs, microblogs (such as Facebook or Twitter) news ar- ticles, and even videos. This is, perhaps, most different from classical computing in that it specializes in unstruc- tured data. According to IBM, up to 80% of all data today is unstructured.[19]
6.1.4 System Development
6.1. INFORMATION SYSTEMS 165
An IT Analyst
The Information Systems Department
The information systems department is also referred to as the information technology department. It is responsible for running, maintaining, and developing the computers and information systems in an organization. They also make sure for the programs to run smoothly. It includes all the computer and network personnel of that organi- zation. The IT person that is most involved in system development is the system analyst. The system analyst manages the things related to designing and implement- ing modified systems. A person that is very important to system development is the business analyst. It is one of the biggest growing jobs because of the large increase in the use of technology. It is all about finding the most effective use of electronic communication.[20]
Systems Development Jobs
security specialists job
Some other IT jobs are business analysts, application pro- grammers, operations personnel, and security specialists. A business analyst will analyze the organization and its documents in order to assess and process that informa- tion. They help understand the policies and actions that a business has and then helps to achieve their business goals. Business analysts make a strategic plan, look at the
business model analysis, process design the organizations work, and then interpret for technical systems. An appli- cation programmer will take the technical and functional parts of a business and review the tech system. They look for ways to increase efficiency, manage things better, and enhance the work system to perform at its best. An appli- cation manager will usually create new applications that combine programs together for efficiency.[21] Operations personal look at things more from a day to day basis and look at ways to improve upon things. This job is use- ful because they get to see the progression of things in the business from one day to the next. Security special- ists will create a secure system to protect the company’s data and information. They will make sure that not ev- eryone will have access to everything in the company’s database. They additionally monitor and respond to se- curity incidents.[22]
Becoming a Systems Developer
Learning to code is a basic skill of any systems developer
In order to be a systems developer one must have basic coding skills. One must know at least one programming language. One must know how to fix problems on the fly if ever a system failure occurs. One must learn to keep maintenance of such systems so that the chances of system failure is minimized. The field itself is highly technical in nature involving plenty of computer science and mathematics in an environment which is always and rapidly evolving with technology. One must also learn how to work in a group for in an organization you will most likely have a defined role in a group of program- mers and system developers. So not only must you have the technical skills but also the soft skills such as commu- nication and teamwork. Possibly even leadership if you were to take in a position wherein you are the leader of the group. You can also work as an adviser to those who are using the systems in business settings. The most im- portant role of the systems developer is to be the support system in the organization in order for everything to be able to run as smoothly as possible.[23]
166 CHAPTER 6. SYSTEMS
Outsourcing
Offshore Outsourcing
In the industry today, many businesses have been out- sourcing their work. Outsourcing occurs when businesses hire others outside of their company to perform differ- ent tasks, like creating new software or databases for the company. Some examples of outsourcing today include customer service, technical support, payroll accounting, and credit card processing. This is becoming more preva- lent through the years because outsourcing has many ad- vantages to the business itself. Offshore outsourcing is another term used, but the work is done in another coun- try. India, for example, is one country that generates much revenue from offshore outsourcing alone. Although many speculate that American jobs are at risk, outsourc- ing to other countries benefits the business as a whole. The company saves a lot more money, than if they were to keep technical support, customer service, etc. in the primary country of that company. Another advantage of having offshore outsourcing is that there can always be someone working on a project, gathering information, and helping a client because of the different time zones. A lengthy project can be completed faster than would a normal project worked on in just the United States be- cause 24 hours a day, somebody is always working on the project. Homesourcing is a new trend that many compa- nies are taking advantage of, and adopting. This is the transfer of service industry employment from offices to home-based employees with appropriate telephone and Internet facilities. One downfall of outsourcing is cul- tural differences. Language barriers can be detrimental to a company at times. Another aspect that companies have to look into is security with newly outsourced em- ployees when they are first hiring.
6.1.5 SDLC - System Development Life Cycle
The System Development Life Cycle (SDLC) is com- posed of six steps. These steps are as follows: prelimi- nary investigation, system analysis, system design, system acquisition, system implementation, and system mainte- nance. Each step is important and builds up on the step(s) that happened previously. While these are generally the steps always used, they do not always occur in the same order. The effects are still the same.[24] Below is an ex- planation of each of the six steps.
Step 1: Preliminary Investigation
Time to dig deeper and investigate!
As the first step in the SDLC, preliminary investigation plays a large role in determining whether or not a sys- tem or system modification would be worth making. The main point of doing a preliminary investigation is to de- termine what problems need to be fixed and what is the best way to go about solving those problems, if solutions do in fact exist. A feasibility report is the product of the preliminary investigation in most cases. The feasibility report is essentially a compatibility test between the cur- rent business/system and the new system/modifications. The report will tell companies if they can afford the change, if it will work with the other systems and technol- ogy already in their company, and if it will be beneficial to the company to make the changes. If all these things come back positively from the systems analyst, then the system will receive the “all clear” to head to the next step of the SDLC.
Step 2: System Analysis
This second step, system analysis, is used to investigate the problem on a larger scale and fine tune all the infor- mation a company has on the issue. Data collection and analysis are the two main points of interest inside system analysis. Gathering information about the current system and users allows analysts to develop an idea of what seems to be the real problem and how they should go about fixing
6.1. INFORMATION SYSTEMS 167
it through data analysis. The main outcome from this step is a grouping of organized data about the current system and the new/modified systems improvements to come.
A Use Case diagram describe the behavior of the system’s user
To illustrate systems that are based on the concept of ob- jects, tools like use case diagrams and class diagrams are used. Use case diagrams are used to describe the behavior of the target system from an external point of view, while also illustrating the users who interact with the system. On the other hand, class diagrams provide an overview of the target system by describing the objects and classes, and their relationships, inside the system.
Analysis
Design
ImplementationTesting
Evaluation
CPT-SystemLifeSycle
As mentioned above, system analysis is the phase of sys- tem development where the problem area is fully stud- ied in depth and the needs of system users are assessed. The tools that will help accomplish this phase of col- lecting data and data analysis are entity-relationship di- agrams (ERDs), data flow diagrams (DFDs), decision ta- bles and decision trees, business process modeling nota- tion (BPMN), and class diagrams and use case diagrams. To describe the use of these tools in depth you will need to understand that any tools or processes used during this phase will aid in understanding the problems or issues of the current systems and how to improve them. So you will see several visual aids, charts, tables, diagrams, mod- els, etc. All this is to help clarify and make sense to all personnel involved how the current system may be im-
proved. Essentially, the new system requirements are de- fined and; in particular, the deficiencies in the existing system must be addressed with specific proposals for im- provement. Entity-relationship diagrams and data flow diagrams are used to model the entities in a system and the flow of data between the entities. So, these kinds of diagrams will create a visual for the logical interaction between the individual entities that use the system. Busi- ness process modeling notation is a graphical, standard- ized notation used to model a business process. This type of modeling is similar to a flowchart and is meant to be understood by all users of the system.[25]
Step 3: System Design
When you're designing a system, you are essentially creating a blueprint with your collected data which you build upon in later steps.
After all of the data has been analyzed, it is time to de- sign a blueprint for the system that specifies what it will look like and how it will work. First you have to develop the design by using a few key tools. One important tool is the creation of a data dictionary, which describes the characteristics of all data that is used in a system. Other important creations that the systems analyst will use in- clude different diagrams which help to better describe the proposed system. It has been argued by some that the ever-increasing rate of developing technology has made it impossible for the every day systems analyst to do their job thoroughly. The economics of industry are pushing in a way that doesn't favor design, only production.[26]
168 CHAPTER 6. SYSTEMS
Whether this is truly the case, system design leaves lit- tle room for error, as time is money.
Are the benefits of the system worth the cost?
In addition to a data dictionary, the systems analyst also has to create input designs to help illustrate the input screens and other user interfaces that will be used to in- put data into the new system. To ensure that the data is input accurately and secured against data loss, it is es- sential for the system design to contain some form of a security feature. Also, an output design helps identify the specific outputs required to meet the information require- ments, select methods required for presenting that infor- mation, and design reports, or other documents that carry the information. Lastly, once the new system has finally been designed, a cost-benefit analysis is performed to de- termine whether the expected benefits (tangible or intan- gible benefits) of the new system are worth the expected cost. This analysis will then help determine if the design for the new system is worth implementing. [27]
Step 4: System Acquisition
Once the design blueprint has been approved, it’s off to the proverbial grocery store. The organization needing a
System Acquisition is a way of going down your shopping list and comparing prices to get the best deals.
system will have a set budget and a list of components needed to make their system work properly. With this budget comes a few courses of action. The first thing to think about is whether the company should create their own software for their system or buy the software from others. It is typically cheaper and less time consuming to buy preexisting software but the customization options are limited. If the preexisting software doesn't offer the options required of the system blueprint, then the com- pany will likely have to make custom software to meet their needs.
1
Standard glossary of terms used in Software Testing
Version 2.1 (dd. April 1st, 2010)
Produced by the ‘Glossary Working Party’ International Software Testing Qualifications Board
Editor : Erik van Veenendaal (The Netherlands) Copyright Notice This document may be copied in its entirety, or extracts made, if the source is acknowledged.
Benchmark Test
Assuming that it okay for the company to buy preex-
6.1. INFORMATION SYSTEMS 169
isting software, the next step is to choose where to buy from. To help them choose, they can prepare an RFP, or request for proposal, which asks vendors what software the company might need to consider buying. If they al- ready know what software they need and just want poten- tial prices, the company can file an RFQ, or request for quotation.[28] After filing for the RFQ, the company must evaluate all of the bids from the vendors offering differ- ent software. The company, in order to make the most profit, should evaluate each bid and figure out which one has charged the lowest price while also reaching the nec- essary criteria for the company’s system. The Purchasing Department of a company usually decides which vendor deserves to receive the quote.[29] The decision is usually helped by the use of a benchmark test. A benchmark test is a systematic process that evaluates both the hard- ware and software of a system. Some determinants used for the test include examining for the amount of work- load that a system is capable of processing, the capability of solving complex scientific problems using a range of computations, offering legitimate data for the system to process and viewing the performance and scalability of the software, and many more. These benchmark tests can be offered through third-party organizations where there sole purpose is to test the offered systems. These tests allow for the company to immediately discard incapable systems offered by vendors. Sometimes benchmarks are not capable of being performed due to a company’s loca- tion or accessibility, but for the most part they are a great way to assist in evaluating which bid is the best.[30] After all of the required software has been purchased it is time for the next step.
Step 5: Implementation
This update manager shows all of the updates needed for a com- puter software, part of the continuous system maintenance
SDLC - Software Development Life Cycle
The implementation phase of the System Development Life Cycle is an important one.[31] In this phase, the new system is installed and made functional in the produc- tion environment, after thorough testing. End user test- ing is imperative to assure a smooth transition. Any re- quired documentation, including instructions and manu- als should be developed during the process. Training, for both the system administrators and end users, should also occur during this phase. During some implementations, it is convenient, and sometimes even necessary to run the old system and the new system in parallel. Once imple- mentation is complete and all users are fully operating in the new system, the old system can be removed com- pletely. One of the advantages of a parallel adoption re- lates to risk. Should the new system fail for any reason, the old system is still in place. Productivity can continue with limited effort in restoration of the old system. There are certain situations where parallel implementation is ill- advised. A significant negative consequences of parallel implementation relates to efficiency. In order for both systems to function effectively, data must be entered into both systems to keep them current. This requires dupli- cation of work and redundancy in effort to maintain con- sistency. In this step, users get the old data ready to be moved, called data migration. Once that is complete, they can begin installing new hardware and software. There are four ways of converting data to new a system: direct conversion- the old system is deactivated and the new one is implemented right away; parallel conversion- both sys- tems are operated at the same time until it is known that the new one is working, then the old one gets deactivated; pilot conversion- only one new system is installed within an organization and once it is known that it works then the rest are implemented; and phased conversion- the new system is implemented by modules by using direct or par-
170 CHAPTER 6. SYSTEMS
allel conversion. There are some advantages and disad- vantages of using each method. For example, the easiest and fastest method is direct conversion. [32] The final ac- tion in this step is training the users with manuals, for example.
Step 6:System Maintenance
Often the system maintenance is the ongoing process throughout the life of the system. Maintenance can in- clude updating software or updating what is already in- stalled. Many of you play an active role in this step al- ready. For example, how many of you keep up with the newest updates for your Apple applications? You are tak- ing part in system maintenance.
System updating
Once a software has been fully implemented, it goes through a post-implementation review to evaluate how the new system is running and whether or not it is completing its intended tasks. System maintenance includes modify- ing existing software or adding completely new features to the existing software, as well as fixing any glitches or bugs and checking security. System updates are usually scheduled for off-peak hours, such as late at night to keep the system running smoothly for users.[33] Updates can be manually downloaded by the user or automatically down- loaded through the server. Automatic updates ensure that the user is constantly using the most up-to-date version of the software. For many organizations, system mainte- nance costs more than the production of the actual system itself. If the system is well designed it should be able to be easily updated and maintained. Poor design makes it difficult to implement new features, which could end the software’s life cycle early. Once a major change is deter- mined to be the best option for a software, an organiza- tion must go through the system development life cycle again to replace the old system from scratch. This next
version may be completely different than the old version with completely new features, or just an updated version of the old features.
6.1.6 System Development Approaches
SDLC - Software Development Life Cycle
Most system development projects include the six basic SDLC phases. However, the exact sequence and tasks performed during each phase, and the names and number of the phases, may vary depending on the organization and the type of system being developed. For example, smaller systems in smaller companies may skip or con- dense some activities, while other development projects may go back and repeat a previous step to refine the pro- cess before moving on. In efforts to improve the system analysis and design process, different methods have been developed. Some of these methods include the waterfall method, the iterative approach, and the end-user method. Each of these methods have different advantages and dis- advantages in a way that they could be used to fit and op- timize different kind of projects.[34] These methods can be compared to our methods of vacation planning. Peo- ple don't design their entire vacation plan as the first step and then execute it, without modification, as the second step. Instead, when the first day of vacation is over, they might use that day’s experience as a basis for modifying the plan for the second day. In this way, system designs are similar.
Traditional Approach
A traditional approach for the system development has five phases which have to be completed in chronological order. First phase is the preliminary investigation. In this process, the team of development investigates the need for possible software automation in the given system. At
6.1. INFORMATION SYSTEMS 171
Example
the end the team creates a document of specific recom- mendations for the candidate system. It includes the per- sonnel assignments, costs, project schedule, target dates, identifies problems and constraint. The second phase is systems analysis which is the study of a problem, prior to taking some action. It refers to the study of the business area or application, usually leading to the specification of the new system. The third phase is systems design which is defined as those tasks that focus on the specification of a detailed computer-based solution. The analyst focuses on three basic elements: the output that must be provided by the system, the source data, or input that the user will provide to the system, the processing needed to produce the output, given the input. The fourth phase is system ac- quisition financial institutions should ensure that systems are developed, acquired, and maintained with appropri- ate security controls. This leads us to the last step which is system implementation, in this phase, the production system is installed, initial user training is completed, user documentation is delivered, and the post implementation review meeting is held. When this phase is completed, the application is in steady-state production. Installation the biggest aspect is that the entire system is planned and built and built before anyone gets to use it or test it, so every aspect to every phase is essential to the traditional approach for system development.[35][36]
Iterative Approach
An example of a prototype design pattern
Unlike the traditional approach, the iterative (repet- itive) approach allows for system testing during development.[37] The emphasis here is on incremental changes through a process known as prototyping. Proto- typing is the creation of software application prototypes. Prototypes, generally speaking, are early models of some product that is created for testing purposes. With soft- ware prototyping, developers are able to receive crucial feedback from testers early in the beginning stages of development. For this reason the iterative approach accounts for potential risks that developers face (e.g. accounting for user needs, verifying accuracy of initial project estimates). With that, the iterative approach acts as a response to the traditional development cycle, which is more likely to have “higher software costs and poor estimates of time and cost” due to the expense of changing a finished product. As the product moves closer to release, the cost of implementing changes increases exponentially.[38] It is a difficult task because the whole system has to be modified to incorporate sudden changes, and this can have undesirable results. Prototyping resolves this by knowing what the user really wants, which leads to increased user involvement. Interaction between users and developers is vital because it ensures what tasks need to be accomplished on the end of the developer. Overall the iterative approach addresses some of the problems that might not be possible for the traditional approach to address.
The End-User Development Approach
Using End-user Development Programs for day-to-day activities
As opposed to the iterative or traditional approach, which both focus on professional users, the end-user develop- ment approach is focused solely on configuring the devel- opment of the system and is often done using tools or pro- grams. Instead of having to be highly educated and a pro- fessional in the area of software or programming, some- one trying to develop a simplistic and easy system can use these programming tools and develop something of their own. A good example of this is sending out an email that someone wanted to be addressed to many people. This is usually used in small businesses, tasks, or daily projects, and is not something that an intricate business would ever use to run their day-to-day software programs. However,
172 CHAPTER 6. SYSTEMS
it is a nice alternative from having to start all over from the beginning and developing brand new software for simple tasks. The end user development approach is also conve- nient for a user who wants to make something their own and customize the way the software runs to fit their per- sonal needs. This approach is extremely useful for indi- viduals who don’t have the knowledge, time, or money to put into building new software from the ground up. The software is easy to use, personal, and a great alternative to the other two options.[39]
6.1.7 Review
Vocabulary Words
business intelligence: The process of gathering, storing, accessing, and analyzing data about a company in order to make better business decisions. computer-aided design: A general term applied to the use of computer technology to automate design functions. data mart: A collection of data related to a particular subject or department in a company. decision support system: A type of information system typically used by upper management that provides peo- ple with the tools and capabilities to organize and analyze their decision making information. enterprise architecture: A comprehensive framework used to describe and manage an organization’s business functions and systems. enterprise system: A system that is used throughout an entire enterprise (business, organization, government agency, and so on). geographic information system: An information sys- tem that combines geographic information with other types of data (such as information about customers, sales, and so forth) in order to provide a better understanding of the relationships among the data. intelligent agent: A program that performs specific tasks to help make a user’s work environment more efficient or entertaining and that typically modifies its behavior based on the user’s actions. management information system: A type of infor- mation system that provides decision makers with pre- selected information that can be used to make middle- management decisions. product lifecycle management (PLM) system: A sys- tem designed to manage a product as it moves through the various stages of its life cycle, from design to retirement. robot: A device, controlled by a human operator or a computer, that can move and react to sensory input. robotics: The study of robot technology. system acquisition: The phase of the system develop- ment life cycle in which hardware, software, and other necessary system components are acquired. system design: The phase of the system development life cycle in which a model of the new system and how it will work is formally established.
system implementation: The phase of the system de- velopment life cycle that encompasses activities related to making the system operational.
Review Questions
1. What is a collection of elements and procedures that interact to accomplish a goal?
2. An __________ is a collection of elements (people, hardware, software, and data) and procedures that interact to generate information needed by the users in an organization.
3. What is a conceptual blueprint that defines the struc- ture and operations of an enterprise (a business, or- ganization, government agency, or other entity.)
4. __________ include the hardware and software needed to create electronic documents, as well as to covert printed documents into electronic form so they can be processed or archived electronically.
5. What are programs that perform specific tasks to help make a user’s work environment more efficient or entertaining?
6. What are software programs that can make decisions and draw conclusions, similar to a human expert?
7. The IT person most involved with system develop- ment is the _________
8. When an organization hires an outside firm to per- form specific tasks, it is referred to as _______
9. What is the phase of system development in which the problem area is studied in depth and the needs of system users are assessed?
10. What focuses on specifying what the new system will look like and how it will work?
Answers:
1. System
2. Information system
3. Enterprise architecture
4. Document processing systems
5. Intelligent agents
6. Expert Systems
7. Systems analyst
8. Outsourcing
9. System analysis
10. System design
6.2. PROGRAM DEVELOPMENT 173
Review References
http://coursemate.cengage.com/ CPReader/View/9781133114598/ default.aspx?eISBN=9781133114598# 8b4c69bb-7aeb-42c4-ae54-2b8d4a8996ba
6.1.8 References [1] http://smallbusiness.chron.com/
types-information-systems-organization-43097.html
[2] http://www.contentmanager.eu.com/dms.htm
[3] http://en.wikipedia.org/wiki/Document_management_ system
[4] Understanding Computers 14th Ed. by Deborah Morley & Charles S. Parker
[5] http://www.slideshare.net/sonnaco/ transaction-processing-system
[6] http://rashedchowdhury.com/2012/11/12/ what-is-an-enterprise-system-how-does-enterprise-software-work/
[7] http://it.emerson.edu/department/erp/
[8] http://www.ehow.com/facts_7584818_ benefits-challenges-enterprise-systems.html
[9] http://www.im.ethz.ch/education/HS08/davenport_hbr_ 98.pdf
[10] http://www.anderson.ucla.edu/faculty/jason.frand/ teacher/technologies/palace/datamining.htm
[11] http://documents.software.dell.com/Statistics/Textbook/ Data-Mining-Techniques
[12] http://www.webopedia.com/TERM/C/CAD_CAM.html
[13] http://en.wikipedia.org/wiki/Computer-aided_design
[14] http://en.wikipedia.org/wiki/Computer-aided_ manufacturing
[15] http://www.bbc.co.uk/schools/gcsebitesize/design/ electronics/manufacturing_processesrev2.shtml
[16] https://en.wikipedia.org/wiki/Decision_support_system
[17] http://www.arnnet.com.au/article/544575/inside_ united_airlines_nerve_center/
[18] http://en.wikipedia.org/wiki/Transcendent_Man
[19] http://www.ibm.com/smarterplanet/us/en/ibmwatson/ what-is-watson.html
[20] http://www.wisegeek.org/what-is-an-it-department.htm
[21] http://www.wisegeek.com/ what-is-an-application-programmer.htm
[22] http://work.chron.com/ computer-security-specialist-do-13655.html
[23] http://www.prospects.ac.uk/systems_developer_job_ description.htm
[24] http://www.veracode.com/security/ software-development-lifecycle
[25] http://searchsoftwarequality.techtarget.com/definition/ systems-development-life-cycle
[26] http://scholar.harvard.edu/files/waldo/files/ps-2006-6. pdf
[27] http://worldinfo4u.com/ what-input-design-output-design-system-design/
[28] http://www.buyingexcellence.com/ should-we-use-an-rfp-or-an-rfq/
[29] http://www.cvtc.edu/about/quotes-bids-proposals/pages/ default.aspx
[30] http://www.nersc.gov/assets/Trinity--NERSC-8-RFP/ Documents/N8BmkInstructAug6Final.pdf
[31] https://airbrake.io/blog/insight/ what-is-system-development-life-cycle
[32] http://web.archive.org/web/20080727015416/http: //web1.arthurphil-h.schools.nsw.edu.au/~{}computin/ Year12/SDD/02_AppSWAapproaches/assets/ MethodsOfImplementation_AdvDisAdv.pdf
[33] http://www.wisegeek.org/what-is-system-maintenance. htm
[34] http://www.umsl.edu/~{}sauterv/analysis/termpapers/ f11/jia.html
[35] http://vcampus.uom.ac.mu/cse1010e/chapter_8/c8_ Sections3.htm
[36] http://business-finance.blurtit.com/105917/ what-is-the-traditional-development-approach
[37] http://www.ibm.com/developerworks/rational/library/ may05/bittner-spence/
[38] http://www.silvercrestconsulting.com/gui/pdf/ 1237375021.pdf
[39] http://www.interaction-design.org/encyclopedia/ end-user_development.html
6.2 Program Development
6.2.1 Program Design and Development
Procedural programming is more or less self explanatory, it’s procedural so it will go step by step in order to solve a problem. This was a much older type of program- ming language that has since been outdated by object oriented programming. However this type of program- ming is very important and should be well understood if you want to understand the concepts of programming and
174 CHAPTER 6. SYSTEMS
Flowchart procedural programming
Object-Oriented-Programming-Methods-And-Classes-with- Inheritance
what all goes into it. This process is also called impera- tive programming in some contexts, meaning top-down languages; this is how the programming functions, from a top to bottom procedural order. This is what makes this process self-explanatory in a way, because in order for something to work and pass along a message we as- sume it to go in this order. Along with going step by step in order to solve a problem, the list of instructions must be sent to the computer in order for it to know what to do with this information. It relies on routines, or pro- cedures, that have multiple steps that need to be carried out. Procedural programming has been somewhat of a stepping stone for other types of programming because of its simplicity. It is an older type of programing and is now outdated by another popular form which is ob-
Similar to this picture, AOP is complimentary to OOP when to- gether
ExampleOfProceduralProgramming
ject oriented programming.[1] Object oriented program- ming is more focused on objects to make a program in- stead specific steps. An object, such as a person, should have a name, or be able to walk, which can be seen as a method in oriented programming. Having a method is this programming is like having a procedure in procedural programming.[2] One of the most popular object oriented programming languages is Java,[3] which is used virtually everywhere. Objects within an object oriented program consists of attributes. If you have ever played D&D[4] you know that your character has different attributes that would define them. If you have an object you can change its attributes like size, shape, and color. Aspect Oriented Programming is a form of program- ming that compliments Object Oriented Programming (or OOP) by allowing the developer to modify OOP in a way where the system can grow to meet new require- ments. It keeps the original model, which was devel- oped in OOP, but allows for new syntax without having to change the compiler being used or reconfigure the editor either. In essence, it is complimentary to the previously developed OOP style and allows the application to adopt new characteristics over its lifetime without having to be completely remodeled or redeveloped. This ability for an application to be adapted to the current trend in technol- ogy prolongs the usefulness and life span of the applica- tion, which then benefit the users of that application as well.[5]
Adaptive software development consists of cyclical spec- ulation, collaboration, and learning rather than the more
6.2. PROGRAM DEVELOPMENT 175
Adaptive software development is a cyclical process.
traditional approach of linear planning, building, and im- plementation. First, the term “speculate” is used, be- cause outcomes can never be fully predicted to the point of “planning”—but also, of course, it would be a waste of time to wander around aimlessly without any organized approach. A mission is still defined; it is just acknowl- edged that the mission can never be inclusive of all pos- sible outcomes and may need to be changed. Second, the term “collaborate” shows that management, per this model, does not just focus on “managing the doing”— i.e. delegating instructions and seeing fit that they are followed—but also focuses on fostering and maintaining a collaborative environment that is needed for real growth to take place. This can be difficult, because, per this model, that environment is often at the “edge of chaos”— that is, a project can't be fully structured, because then nothing new can emerge, but things can't teeter over the edge into anarchy. Finally, there is a focus on learning from mistakes on the part of both the developers and the consumers. These three-phase cycles are short so that small mistakes, not large ones, are the ones from which lessons are learned.[6]
6.2.2 Program Development Life Cycle - Analysis, Design, Coding
The following are six steps in the Program Development Life Cycle: 1. Analyze the problem. The computer user must figure out the problem, and the best program to fix it. 2.Design the program. A flow chart is important to use during this step of the PDLC. This is a visual diagram of the flow containing the program. All in all, this step is breaking down the problem. 3. Code the program. This is using the language of pro- gramming to write the lines of code. The code is called
SoftwareDevelopmentLifeCycle
the listing or the source code. The computer user will run an object code for this step. 4. Debug the program. The computer user must debug. This is the process of finding the “bugs” on the computer. The bugs are important to find because this is known as errors in a program. 5. Formalize the solution. One must run the program to make sure there are no syntax and logic errors. Syntax are grammatical errors and logic errors are incorrect results. 6. Document and maintain the program. This step is the final step of gathering everything together. Internal doc- umentation is involved in this step because it explains the reasoning one might of made a change in the program or how to write a program.[7]
Writing Code
Example of a Code Editing Software
Essentially, computer code is a series of statements that have been assigned a function by a higher level language (typically referred to as source code). This language is similar to English and has been converted to machine language using a type of program known as a compiler. Because code is used to instruct computers to perform
176 CHAPTER 6. SYSTEMS
a wide array of tasks, there are many different kinds of languages and programs available. One of the most im- portant aspects of coding is deciding which jobs (creat- ing a web page, writing a game, etc.) a computer will do. Regardless of what is chosen, the majority of codes uti- lize plain-text because of its compatibility. Though the actual content is written this way, documents are each given a unique file extension that is indicative of their type. One can write a simple code with a basic word processor or text editor. However, using a software ap- plication (specifically designed for coding in a particu- lar language) is significantly more effective and efficient. As with a document written in English, where word pro- cessing software is used to aid in detection of spelling errors and non-standard grammar, a coding editor pro- vides comparable tools to ensure accuracy. A code editor is also known as an integrated development environment (IDE), which is a software application for formatting. A large downfall of working with IDEs is a lack of flexibil- ity. While some IDEs work with multiple programming languages, a sizable amount are very specific for only one language. [8]
Flowcharts and Pseudocode
Common symbols used in flowcharts
During the design process of the Program Development Life Cycle, it is important that programmers (and non- programmers) are able to visualize the way in which the program will work. Certain tools such as flowcharts and pseudocode are used to simplify the design process and allow the developers to see the program before any ac- tual coding is used. A common type of design tool is the flowchart. A flowchart can be either handwritten or cre- ated with software such as Visual Logic or Flowgorithm [9] Many of these software programs have similar sym- bols to represent certain actions such as input, output, assignments, and various types of loops. Flowcharts are also useful for education tools because they focus more on the concept of programming rather than focusing on the syntax of languages. Another type of design tool is pseudocode. Pseudocode is very similar to a program- ming language except that it uses non-syntactical words to summarize the processes of a program. Pseudocode can- not be compiled or executed but it does serve as a good starting point for programmers.[10] Here is an example of pseudocode:
If user’s age is greater than or equal to 18:
Print “You can vote” else
Print”You cannot vote”
Compiler
Codice sorgente
Analisi lessicale
getNextToken
Analisi sinattica
Analisi semantica
Generazione del codice
Programma eseguibile
NextToken
Abstract Syntax Tree
AST modificato
Assembly
Multi-pass compiler
A compiler is a special program that processes state- ments written in a particular programming language and turns them into machine language or “code” that a com- puter’s processor uses. When executing (running), the compiler first parses (or analyzes) all of the language statements syntactically one after the other and then, in one or more successive stages or “passes”, builds the out- put code, making sure that statements that refer to other statements are referred to correctly in the final code. A compiler works with what are sometimes called 3GLs (FORTRAN, BASIC, COBOL, C, etc.) and higher-level languages.[11] There are one-pass and multi-pass compil- ers as well as just-in-time compiler, stage compiler, and source-to-source. The compiler frontend analyzes the source code to build an internal representation of the pro- gram, called the intermediate representation. The com- piler backend includes three main phases, such as analy- sis, optimization, and code generation.[12] Because com- pilers translate source code into object code, which is unique for each type of computer, many compilers are available for the same language. For example, there is a FORTRAN compiler for PCs and another for Apple Macintosh computers. In addition, the compiler industry is quite competitive, so there are actually many compil- ers for each language on each type of computer. More than a dozen companies develop and sell compilers for the PC.[13]
6.2. PROGRAM DEVELOPMENT 177
6.2.3 Program Development Life Cycle - Debugging and Testing, Implemen- tation and Maintenance
Control Structures
Process
Process Process
Selection control structure involving a condition
A control structure is a diagram used to show how func- tions, statements, and instructions are performed in a pro- gram or module. The diagram shows exactly when an instruction is performed, and how it’s performed. Most importantly, a control structure shows the order of the instructions.[14] There are three basic types of control structures: sequence, selection, and repetition. Choosing a specific control structure depends on what you want the program or module to accomplish. A sequence control structure is the simplest and least complex control struc- ture. Sequence control structures are instructions that are executed one after another.[15] The structure could be compared to following a recipe. A more complex control structure might be a selection control structure, a struc- ture that involves conditions or decisions. This means that the structure can allow different sets of instructions to be executed depending on whether a condition is true or false.[16] The last basic control structure is a repetition control structure, which is sometimes called an iteration control structure. This control structure is used when re- peating a group of code is necessary. The code will be repeated until a condition is reached. Repetition control structures are used when looping is needed to reach a spe- cific outcome.[17]
Testing Program Design
Good program design needs to be specific. The program design is very important, especially because it involves the overall step-by-step directions regarding the program. A programmer must test the program design to ensure that it runs correctly and that there are no mistakes. The op- eration a programmer must do to complete this task is called desk checking. Desk checking allows the program- mer to run through the program design step-by-step. Es-
For (A ;B;C) D Loop
A
B
TRUE
FALSE
C
D
Programming Loop
sentially, the programmer runs through lines of code to identify potential errors and to check the logic. The pro- grammer uses tracing tables to keep track of any loop counters. The goal of checking the program design is to avoid running into mistakes further on in the program de- velopment cycle. The sooner the mistake is caught in the development cycle the better. If the error is not found un- til later in the developmental cycle, it may delay a project. Therefore, a programmer must make sure they pay strict attention while desk checking. Advantages to desk check- ing include the convenience of hands-on “proof-reading” of the programmer’s own code. The programmers wrote the code themselves, so it is an advantage that they can work immediately with familiar code. A disadvantage to the desk checking system includes potential human error. Since a computer is not checking the design code, it is prone to human error.[18]
Debugging
Debugging is basically making sure that a program does not have any bugs (errors) so that it can run properly with- out any problems. Debugging is a large part of what a pro-
178 CHAPTER 6. SYSTEMS
grammer does. The first step to debugging is done before you can actually debug the program; the program needs to be changed into machine language so that the computer can read it. It is converted using a language translator. The first goal of debugging is to get rid of syntax errors and any errors that prevent the program from running. Errors that prevent the program from running are com- piler errors. These need to be removed right away be- cause otherwise you cannot test any of the other parts of the program.[19] Syntax errors occur when the program- mer has not followed the correct rules of the program- ming language. Another kind of error is a runtime error, which occurs while the program is running and it is not noticed until after all syntax errors are corrected. Many run time errors are because of logic errors, which are er- rors in the logic of the program. It could occur when a formula is written incorrectly or when a wrong variable name is used.[20]
Debugger in action
There are different types of debugging techniques that can be used. One technique called print debugging, or also known as the printf method, finds errors by watch- ing the print (or trace) statement live or recorded to see the execution flow of the process. This method origi- nated in the early versions of the BASIC programming language. Remote debugging is the method of finding errors using a remote system or network, and using that different system to run the program and collect informa- tion to find the error in the code. If the program has al- ready crashed, then post-mortem debugging can be used through various tracing techniques and by analyzing the memory dump of the program. Another technique is one created by Edward Gauss called wolf-fence debugging. Basically, this method find the error by zeroing in on the problem by continuous divisions or sectioning until the bug is found. Similar to this is the saff squeeze technique which uses progressive inlining of a failure test to isolate the problem.[21]
Debugging a program can be done by using the tools provided in the debugging software. Typically, and es- pecially with high-level programming languages, specific debugging tools are already included in the. Having
language-specific debugging tools make it easier to detect the errors in a code, because they can look for known er- rors as opposed to tediously “walking through” the code manually. It also good to note that fixing one bug manu- ally may lead to there being another bug; this is also why language-specific debugging tools are helpful. There are also debugging software for embedded system as well.[22]
Testing/Implementation and Maintenance
Testing
Relating to getting a program up and running, many things need to happen before it can be used. One step is to test the program. After the debugging process oc- curs, another programmer needs to test the program for any additional errors that could be involved in the back- ground of the program. This person needs to perform all of the tasks that an actual user of the program would use and follow. To ensure privacy rights, test data is used in the testing process. However, this still has the same structure and feel to the actual data. The tester needs to check for possible input errors as well, as this would cre- ate many problems and issues in the future had it not been checked. Companies usually implement different types of tests. An Alpha test [23] is first conducted, which is on-site at the company, and Beta tests are sent out to dif- ferent states or countries to ensure the program is 100% ready for use. The Alpha test occurs before the Beta test. Once the debugging and testing are finished, the program is now in the system and the program implementation and maintenance phase are completed. Program maintenance still needs to be kept up, in case of future errors. This is the most costly to organizations because the program- mers need to keep improving and fixing issues within the program. As stated earlier, a program goes through extensive test- ing before it is released to the public for use. The two types of testing are called Alpha and Beta testing. First, it is important to know what each test does. Alpha testing is done “in house” so to speak. It is done within a com- pany prior to sending it to Beta testing and its intention in this early stage is to improve the product as much as possible to get it Beta ready. Beta testing is done “out
6.2. PROGRAM DEVELOPMENT 179
Prog
of house” and gives real customers a chance to try the program with the set intention of catching any bugs or errors prior to it being fully released. Alpha testing is the phase that takes the longest and can sometimes last three to five times longer than Beta. However, Beta testing can be completed in just a few weeks to a month, assuming no major bugs are detected. Alpha testing is typically per- formed by engineers or other employees of the company while Beta testing occurs in the “real world”, temporar- ily being released to the public to get the widest range of feedback possible. During Alpha testing, it is com- mon for there to be a good amount of bugs detected as well missing features. During Beta testing, there should be a big decrease in the amount of these problems. When testing in the Alpha phase is over, companies have a good sense of how the product performs. After Beta testing is complete, the company has a good idea of what the cus- tomer thinks and what they experienced while testing. If all goes well in both phases, the product is ready to be re- leased and enjoyed by the public. The length of time and effort that is put forth in order for the world to enjoy and utilize the many programs on computers today is often overlooked. Information such as this gives the user a new appreciation for computers and computer programs.[24]
6.2.4 Program Development Tools
Adobe Air
Adobe Air allows the user to package all of the code into applications for Windows, MacOS, iOS, and An- droid desktops. Adobe air reaches billions of desktops and apps for 500 million devices. There are many ap- plications that can be used with adobe air. Adobe air can open books online and allow the user to be able to read them easily that way. You can change the font size, quickly get to a page, and go to a full screen while reading the book. Adobe Air can also open desktop blog editor and allow the user to use HTML/Javescript. An example of this type of application is Bee. It can use word to start a
Adobe Acrobat dot com (2010)
blog and the user can add photos easily and allow the blog to flow evenly. BkMark is another application that can be used on Adobe Air. It allows the user to make bookmarks for favorite websites. It store actual data and allows you to reopen any website that you want to go to. It is really convenient application for users who want something fast to go to a commonly used website. Finally another ex- ample of an application that can be used with Adobe Air is dAIRnotes. This allows the user to make notes on the computer and keep track of all of the notes.[25]
Application Lifecycle Management (ALM) Tools
Programmers are often overworked and need all the help they can get. This is where ALM tools come into play.
ALM tools are, surprise surprise, tools that manage an application throughout its entire life cycle. They are very helpful for programmers who are under increas- ing amounts of stress to develop new programs quickly. The helpfulness comes from wide range of features that the ALM tools can offer. One example is how many ALM programs come with built-in program design tools, along with the ability to generate the program code from the finished design to create the application. This code
180 CHAPTER 6. SYSTEMS
generating ability saves companies time and money that they don't have to put towards outsourcing, especially if they've got a small number of programming staff. In ad- dition to code generators, another important tool that can be included in ALM programs is requirements manage- ment. Essentially, requirements management is defined in exactly that way, referring to keeping track of and man- aging program requirements as they are defined and then modified throughout the process of developing the pro- gram. The larger the company, the nicer ALM toolset they can purchase; there are many ALM toolsets on the market to choose from.[26]
Application Generators
Keyboard shortcuts (like those used to initiate the use of a macro)
Application generators are extremely useful devices. They can be used by amateurs/people with less experi- ence or by professionals. The point of an application generator is to make a task simpler than it is. Even if it is just changing a few basic formatting characteristics, these generators can make it so that the user only has to type in a specific key or command in order for all the actions to happen at once with much less effort. One of these useful generators is called a Macro. A macro is an application generator that simply makes it possi- ble to perform repeated actions instantaneously on a sin- gle command. The idea is that it will make reformatting or calculating things much easier, thus saving the oper- ator time.[27] Most Microsoft programs contain a macro recorder which allows users to easily record all inputs and commands they use and associate them with a keyboard shortcut for future repetition. Other application genera- tors create reports and form which make things such as memberships, records (such as medical treatments, his- tory, and vaccinations), and even insurance claims more organized and easier to access by those who should be able to access them.
RIA Tools
Java Rich Internet Applications
Other types of tools include device software develop- ment tools, software development kits (SDKs), applica- tion program interfaces (APIs), and rich internet applica- tion tools (RIAs). A rich internet application offers many of the same features associated with desktop applications. They are more interacting and engaging that other web- based applciations. Some big names in this area are Mi- crosoft, Adobe, and JavaScript. Microsoft actually has a very put together developer’s website that goes into some detail about how to create such applications. It includes information such as things to consider before starting an RIA, such as the audience. [28]
A few key features about RIAs include direct interac- tion, partial-page updating, better feedback, consistency of look and feel, offline use, and performance impact. [29]
Direct interaction allows for a wider range of controls, such as editing or drag-and-drop tools. Partial-page up- dating allows for real-time streaming and cuts down on load time waiting for a response from a server. RIAs can provide users with quicker feedback because of the partial-page updates. Also, it is sometimes possible to use RIAs offline when there is no connectivity. Once downside to RIAs is that smaller devices, such as mobile phones, often times do not have the means necessary to run such applications.
6.2.5 Programming Languages
What is a Programming Language?
Program Language
A programming language is designed to communicate in-
6.2. PROGRAM DEVELOPMENT 181
structions to a computer and so the computer can inter- pret the instructions and make sense of them. They are used to create programs that control the behavior of a machine and algorithms. There are multiple languages created into this program which are created from differ- ent styles or forms. The description of a programming language is known to be split into the two components of syntax (form) and semantics (meaning). The syntax is the form in which the language is presented in and the actual sense or meaning of the instructions is the seman- tics. A program is written so that it can be understood by computer so that the instructions can be interpreted, translated into so the computer can eventually make sense of it. So the moment you turn on your computer after it starts to run programs, it interprets these instructions, tests the ram and resets all attached devices and loads the operating system from hard disk. Every operation that the computer holds has instructions that someone had to translate into a programming language. With every lan- guage, they have to be created, compiled and tested which tends to be a long and complex task.[30]
Categories of Programming Languages
Visual Basic is an example of a high-level programming lan- guage.
Two categories that programming languages can fall un- der are procedural (programs that use the procedural approach) and object (for those programs that use the object-oriented approach). However, probably the most common way of categorizing programming languages is by their designation into a tier structure. Programming languages can fall under low-level languages, high-level languages, and very high-level languages. Low-level lan- guages, which are made up of the first generation lan- guage, machine language, and second generation lan- guage, assembly language, are written at a very low level: programming consists of 0s and 1s for machine language and assembly language includes names and symbols for some of the 0s and 1s. These languages allow computer hardware to read commands quickly, but this happens at the cost of a much steeper learning curve as opposed to higher level languages.[31] High-level languages, on the other hand, are easier to use because they are closer to natural language. They are also machine independent: programs written on one computer can be transferred to another computer without modification. This is in con- trast to the machine dependent-nature of low-level pro- grams where modification is necessary. Lastly, very high-
level languages, also known as fourth-generation pro- gramming languages, are more difficult to distinguish from high-level languages. Fourth-generation languages (4GLs) are known to be declarative, which does not spec- ify exactly how a computer should go about processing a command. This results in programmers using very little code. Although, those languages deemed very-high level languages in the past (e.g. Visual Basic, Python, Perl) have now been called simply high-level languages [32]
Official Scratch Wiki Logo
There are some high-level programming languages that are visual programming languages or graphical program- ming languages. They are referred to by these names be- cause they have a graphical interface. In these programs, instead of typing program code, a user can drag and drop objects to generate the needed code. There are even pro- grams that incorporate visual elements that help with cod- ing but also still require actual coding. These kinds of programs are called visual programming environments (VPEs) One of the first programming languages to use a visual programming environment was Visual Basic. The convenience of visual programming environments is that you can drag and place objects but also with a code is typed, the program assists in creating the code by listing options. These helps users learn appropriate codes. An online definition of visual programming environments describes it as software which allows the use of visual expressions (such as graphics, drawings, and animations or icons) in the process of programming. These visu- als items are then used as graphical interfaces for textual programming languages. These kinds of visual program- ming languages software are also used for educational purposes and in the future may be the most common pro- gramming language. Scratch is one example of an ed- ucational visual programming environment for children. As mentioned above, Visual Basic was one of the first programming languages to use visual programming envi- ronment, but since then C++, Pascal, and Java have also
182 CHAPTER 6. SYSTEMS
begun to create visual programming environments.[33]
Common Programming Languages
Fortran is one example of a very common programming lan- guage.
There are many programming languages out there that are still, to this day, used immensely on a day-to-day basis. Fortran, which is one of the older options, is used mainly in the scientific field for scientists, mathematicians, and formulating numerical formulas. Cobol is another pro- gramming language commonly used today, and can typ- ically can be seen utilized in business environments for everyday transactions. This language is seen as extremely time consuming, and more and more businesses today are starting to move away from it, towards quicker processes. Pascal is yet another language that is used commonly in math and science programs. The Pascal programming language obtained its name from the famous mathemati- cian, Blaise Pascal. It was created by Niklaus Wirth, a member of the International Federation of Information Processing Working Group. He created the Pascal pro- gramming language because he wanted to include new features that past programming languages did not pro- vide. It was originally created as a teaching tool and uses control structures in its software. The use of con- trol structures helped the programming language become more structured and organized compared to other lan- guages, which is why it was used as a teaching tool. Pas- cal was published in 1971 and revised in 1973, which al- lowed for it to stay prominent in colleges from the 1970’s and into the late 1980’s. One of the new features of Pas- cal was the new data types, like Integer, Real, Character,
and Boolean. These new types are what allowed Pascal to become a programming language used strongly in math- ematic programs. Another new feature was a strong data typing element, which allowed the compilers for Pascal to see and correct an incompatible assignment in one type in accordance to a variable in a different type. This further helped keep the organized structure of Pascal and enabled it to be used more in college level classes. Pascal was a great creation for the programming language world.[34]
The Pascal programming language was named after Blaise Pas- cal, a mathematician.
Another common programming language is Basic. It is one of the most used languages because it can be con- sidered user friendly. It was designed to be an uncom- plicated and stressful language that is used typically for interactive programs. It is extremely easy to get to know, and many people enjoy its simplistic and understandable functioning. One aspect of basic is Visual Basic, which again uses their understandable language, but is focused on visual aid. These are just a few examples of the im- mense and intricate amount of languages that are out there. Though many of these are still used today, it is obvious that some of the older and more time-consuming software is on its way out.[35]
On the other hand, there are also some programming lan- guages that are no longer widely used today. Among these programming languages are LISP and Prolog. Speci- fied in 1958, LISP (LISt Processing) is the second-oldest high-level programming language, running right behind Fortran. It allows a code to be expressed in the same form as the data structures in the language, which is very beneficial when performing genetic algorithms or sym- bolic manipulation. On the other hand, in the early 1970s,
6.2. PROGRAM DEVELOPMENT 183
In Logo, by inputting text commands into a prompt, the user moves the cursor around the screen to create squares, stars, and other shapes
Prolog was designed for natural language processing, and logical reasoning. This language allowed using similar grammars to translate logical representation back into language.[36] Being a dialect of LISP comes another lan- guage used to teach children how to program: The Logo Programming language. To act as a tool for learning, its features included modularity, extensibility, interactiv- ity, and flexibility. Another third generation program- ming language not used today is PL/I, “Programming Language 1.” This language was developed as an alterna- tive to Cobol (large-scale business applications) and For- tran (scientific and algorithmic applications). Lastly, and most importantly, comes one of the first object-oriented programming languages: SmallTalk. As there is no such language called SmallTalk any more, other different lan- guages like SmallTalk-xx (the xx being the year that the language was finalized,) have gradually taken its place. Therefore, although new languages such as C, Java, or PHP have now taken over, old programming languages still play a significant role behind the shift to the new and better technology. [37]
Java is a high-level, object-oriented programming lan- guage that is designed to let developers write once, run anywhere. This means that the coding does not have to be recompiled for various platforms and can run the same on any system. The language was developed by Sun Mi- crosystems in 1995 and was released to the public as open source software in 2007.[38] Since then, the language has become one of the most popular programming languages in the world, particularly for client-server web applica- tions. Much of the syntax used is derived from other pro- gramming languages C and C++. Java programs are com- piled into the bytecode format, which can be run on any computer that runs Java virtual machine no matter how simple or complex the computer’s architecture may be.
One popular application for the Java language is Java ap- plets, which are small programs that can be inserted into a web page of a java-enabled web browser. These applets can be used to run games, banner ads, scrolling text, or various other types of programs from inside the browser. These applets are inserted into the HTML statements of the web page just as an image would be added. The ap- plet is downloaded from the host server of the webpage when being displayed, allowing for the program to run on the viewer’s computer.[39]
Python
Python is an open source, dynamic object-oriented pro- gramming language. Python can be used to develop a variety of applications, including gaming, database, and Web applications. It’s a freely available programming language and can run on almost any computer without needing to change the program. Python’s compatibil- ity is the reason it’s used daily in the Google search en- gine, Youtube, NASA, and the New York Stock Ex- change. Also, due to its readability, ease of acquisition, and extensibility, Python was recently chosen by MIT for students learning to program.[40] Another open source object-oriented programming language, often compared to Python, is Ruby. Ruby can be used to create both Web applications and general-purpose programming for Linux, Mac OS X, and Microsoft Windows computers. Similar to Python, Ruby uses a syntax that is relatively easy to read and write. A difference, however, is that Ruby tends to presume upon the programmer’s intentions, while Python’s information is typically plain in syntax. Ruby on Rails (RoR) is a framework for developing dy- namic Web applications that are written in the Ruby pro- gramming language. RoR applications run on a variety of types of Web servers and with a variety of databases, consequently growing rapidly in use and popularity.
184 CHAPTER 6. SYSTEMS
Java Java is another very common programming lan- guage. It was developed by Sun Microsystems (who were later bought by Oracle), and bases most of its syntax off the other programming languages such as C and C++. Java is used extensively in apps, both on computers and mobile devices. Is is liked by app developers as it is easy to use, and compatible with most devices as most devices are able to read Java. Mobile devices are making use of Java in many of their systems, as it is compact, and can be used for many operations in the device. Android uses Java as a major part of their mobile operating system. While not the foundation of the operating system Java is used for most of the non-basic functions. In regards to the mobile phone market, Java’s biggest competitor is Google, as they are marketing their own operating system for use on mobile devices. Java is found in most devel- oped apps, but programmers to create simple programs from scratch. The major downside of Java, as with any programming language, is that it may expose weak areas that can be hacked. Java is currently on its 8th edition, with a 9th edition being beta tested.[41]
MS-DOS and Batch Files
Batch processing has been in use since the 1950’s in main- frame computers. [42] This started on punch cards, how- ever it developed into a fully digital language. MS-DOS is an acronym that stands for “Microsoft Disk Operating System”. MS-DOS has an interface that is just a black screen with white text on it. Since the early days of com- puting, DOS has been used to read and write programs for a myriad of jobs. The MS-DOS Batch language is simply a text file that allows a user to create a sequence of commands that are executed as if they were typed in to the command line, with some enhancements for con- ditionals (making decisions based on whether programs fail or succeed). Over the years, various batch versions of varying capabilities have appeared on many comput- ing platforms. The command prompt (as it is now called) still appears on modern Windows and Linux machines, and many IT professionals swear by it, and by the power and control it gives them. This ability to automate com- mon tasks s often a budding programmer’s first exposure to programming languages.
6.2.6 Key Terms Review
Procedural programming: An approach to program design in which a program is separated into small mod- ules that are called by the main program or another mod- ule when needed. Variable: A named memory location defined in a com- puter program that is used to store the current value of a data item used in that program. Object-oriented programming (OOP): An approach to program design in which a program consists of objects
that contain data (attributes) and processes (methods) to be used with those objects. Aspect-oriented programming (AOP): An approach to program design in which different functions are clearly separated so program components can be developed and modified independently from one another, and the com- ponents can be easily reused with separate, nonrelated ob- jects. Program development: The process of creating appli- cation programs. Program development life cycle (PDLC) The process containing the five phases of program development: ana- lyzing, designing, coding, debugging and testing, and im- plementing and maintaining application software. Problem analysis: The phase of the program develop- ment life cycle in which the problem is carefully consid- ered and the program specifications are developed. Programmer: A person whose job it is to write, test, and maintain computer programs. Program design: The phase of the program develop- ment life cycle in which the program specifications are expanded into a complete design of the new program. Flowchart: A program design tool that graphically shows step-by-step the actions a computer program will take. Pseudocode: A program design tool that uses English- like statements to outline the logic of a program. Unified Modeling Language (UML): A set of standard notations for creating business models; widely used for modeling object-oriented programs. Control structure: A pattern for controlling the flow of logic in a computer program, module, or method. Sequence control structure: A series of statements that follow one another. Selection control structure: A series of statements in which the results of a decision determine the direction the program takes. Repetition control structure: A series of statements in a loop that are repeated until a particular condition is met. Program coding: The phase of the program develop- ment life cycle in which the program code is written using a programming language. Coding: The process of writing the programming lan- guage statements to create a computer program. Source code: A computer program before it is compiled. Program debugging and testing: The phase of the pro- gram development life cycle that ensures a program is correct and works as intended. Debugging: The process of ensuring a program is free of errors. Object code: The machine language version of a com-
6.2. PROGRAM DEVELOPMENT 185
puter program generated when the program’s source code is compiled. Language translator: A software program that converts source code to object code. Compiler: A language translator that converts an entire program into machine language before executing it. Interpreter: A language translator that converts program statements line-by-line into machine language, immedi- ately executing each one.
6.2.7 Review Questions
1.) What is a computer program called before it is com- piled? 2.) A program design tool that graphically shows step-by- step the actions a computer program will take is called a _______? 3.) What phase of the PDLC has the program code writ- ten using a programming language? 4.) If your job is to write, test, and maintain computer programs, you are a _______. 5.) What language translator converts an entire program into machine language before executing it? 6.) What process ensures a program is free of errors? 7.) What is the process of creating application programs? 8.) How many phases are there in the program develop- ment life cycle? 9.) List the phases of the PDLC in order. 10.) What is a software program that converts source code to object code?
6.2.8 Review Answers
1.) Source code 2.) Flowchart 3.) Program coding 4.) Programmer 5.) Compiler 6.) Debugging 7.) Program development 8.) Five 9.) Analyzing, designing, coding, debugging and testing, implementing and maintaining ap- plication software 10.) Language translator
6.2.9 References
[1] http://education-portal.com/academy/lesson/ object-oriented-programming-vs-procedural-programming. html#lesson
[2] http://education-portal.com/academy/lesson/ object-oriented-programming-vs-procedural-programming. html#lesson
[3] http://www.java.com/en/
[4] http://www.wizards.com/dnd/
[5] http://www.onjava.com/pub/a/onjava/2004/01/14/aop. html
[6] http://www.adaptivesd.com/articles/messy.htm
[7] http://blog.teachbook.com.au/index.php/ computer-science/software-development/ program-development-lifecycle/
[8] http://study.com/academy/lesson/ how-to-write-a-program-coding-testing-debugging. html
[9] https://en.wikipedia.org/wiki/Flowgorithm
[10] http://www.webopedia.com/TERM/P/pseudocode.html
[11] http://whatis.techtarget.com/definition/compiler
[12] http://en.wikipedia.org/wiki/Compiler
[13] http://www.webopedia.com/TERM/C/compiler.html
[14] Understanding Computers 14th ed. by Deborah Morley & Charles Parker
[15] http://www.britannica.com/EBchecked/topic/1086517/ sequence
[16] http://www.thevbprogrammer.com/Ch05/ 05-03-SelectionStructure.htm
[17] http://www.cs.fsu.edu/~{}myers/c++/notes/control1. html
[18] http://www.ehow.com/facts_5941523_desk-checking_ .html
[19] http://searchsoftwarequality.techtarget.com/definition/ debugging
[20] http://www.techopedia.com/definition/16373/debugging
[21] http://en.wikipedia.org/wiki/Debugging
[22] http://en.wikipedia.org/wiki/Debugging
[23] http://www.thefreedictionary.com/alpha+test
[24] http://www.centercode.com/blog/2011/01/ alpha-vs-beta-testing/
[25] http://www.adobe.com/devnet/air/samples_javascript. html
[26] http://www.infoq.com/research/alm-survey
[27] http://office.microsoft.com/en-us/help/ macros-demystified-what-they-are-and-why-to-use-them-HA010007210. aspx
[28] http://msdn.microsoft.com/en-us/library/ee658083.aspx
[29] http://www.computerworld.com/s/article/335519/Rich_ Internet_Applications?taxonomyId=16&pageNumber=2
[30] http://cplus.about.com/od/introductiontoprogramming/ p/programming.htm
[31] http://www.webopedia.com/TERM/M/machine_ language.html
186 CHAPTER 6. SYSTEMS
[32] https://en.wikipedia.org/wiki/Very_high-level_ programming_language
[33] http://dictionary.reference.com/browse/visual+ programming+environment
[34] http://groups.engin.umd.umich.edu/CIS/course.des/ cis400/pascal/pascal.html
[35] http://www.freerepublic.com/focus/chat/2880277/posts
[36] http://www.princeton.edu/~{}achaney/tmve/wiki100k/ docs/Lisp_(programming_language).html
[37] http://el.media.mit.edu/logo-foundation/logo/
[38] https://www.java.com/en/download/faq/whatis_java. xml
[39] http://en.wikipedia.org/wiki/Java_(programming_ language)
[40] http://python.about.com/od/gettingstarted/ss/ whatispython_7.htm
[41] https://www.oracle.com/java/index.html
[42] https://www.microsoft.com/resources/documentation/ windows/xp/all/proddocs/en-us/batch.mspx?mfr=true
6.3 Database
6.3.1 Database Definition and Examples
Phone book
A database is a collection of data that is saved and or- ganized to allow easy retrieval when needed. In order to
maintain and access the database you will need a DBMS (database management system). This kind of system manages and protects data so that the database is safe and secure. Databases consists of tables that include groups of related data fields that are known as records. Databases are not limited to only computers; in fact, a phone book is an example of a database.[1] All of the names alpha- betized and each column has its own category. There is a column for your name, phone number, and possibly a street address. With a relational database, all of the data within the row can be pulled up when you are looking for the specific attribute.
All that data has to be stored somewhere!
There are a few advantages to using a database manage- ment system. On the plus side, it has the ability to control redundancy, the integrity of the information being stored can be maintained, it can restrict access, it can share data, and can backup/recover information. A database man- agement system can counteract redundancy by compiling the information in one spot. The same way that you can't have two audio files with the same name and extension in a single folder, you can't have the same file in a single database. This controls and can increase storage space. The integrity of the information being stored can also be increased based on the specifications of the database de- veloper. This means that the constraints on the informa- tion put into the database (which is determined by the developer) will keep the data stored accurate. So if a database is only able to store pictures, for example, then a music file will be rejected ensuring that a picture will al- ways be retrieved from the database with 100% accuracy. This is a very simple example to get the idea across as the constraints imposed by the developer can determine dif- ferent things. Databases can also share data as well allow- ing a developer to build multiple applications off of one source of information rather than having to create new stored files. Databases can also backup and recover data. If a computer system fails during a long, complex update
6.3. DATABASE 187
then the database can restore the files to the place in the update when it is becomes operational again.[2]
Microsoft Access 2013 logo
Primarily, databases are used for collecting data and orga- nizing, one may wonder what instances this may be used for. Some examples of databases are Microsoft Excel or Access. For an example of what these databases could be used for we can go with a situation: you are having a wedding and need to make an invitation list. For a pro- cess like this, users can utilize Microsoft Excel because their database will not have many types of transactions and should not become too uncontrollable. However, if this were to happen, Access would be more compatible with the material needed. Access is basically just a more advanced version of Excel that is only needed for uncon- trollable databases or ones that need to be directly linked to others in order to access information in an systematized way. Either database can help you make informed deci- sions and can also help you make sense of the data in dif- ferent ways. The storage in Access is not repetitive so it can essentially save space and improve accuracy.[3] Ac- cess also has different templates to choose from so that you do not have to create a new database from scratch. There is also a relationship you can establish between the tables so that you can navigate easier. For creating a wed- ding invitation list: you can decide who to invite and who not to invite to the reception and put those people in sep- arate tables.[4]
Databases are also important in businesses. Especially when it comes to keeping inventory. Databases can be used for controlling inventory as well as reducing the time, cost, and effort of inventory management. Control- ling your inventory is essential in order to have good and efficient business. A database can provide an up-to-date picture of stock levels and products. It helps in main- taining that the stocks keep up with the demand of the consumers. It can be used to provide forecasts and trends of demand in order to adjust adapt to the change of the
These items need to be organized somehow.
market and maximize profit. It also provides automation which improves productivity. It can update stock levels automatically as well as control stock to ensure products are always available for consumers. This automation frees up employees to do more productive things such as help out customers. Speaking of customers, they always order things and want them delivered on time and right away. Well a database can help in increasing and maintaining the efficiency of orders and deliveries. They help make it easier to place orders and find products. While these are also important in business they can be applied to any or- ganization that may have inventory. An example of such would be libraries. With he millions of books that a li- brary can potentially carry, a database is not only impor- tant but necessary.[5]
Who Uses Databases?
A database whose creation and use involve many people.
There are a number of individuals who create, use, manage, and secure database management systems. A database designer is responsible for designing a database. They work with people involved in the sys- tem development life cycle, such as systems analysts, to find out what kinds of data are needed and what rela- tionships among the data should be studied, and they de- sign the database based off of these. A database de- signer may also be referred to as a database architect, database engineer, or database analyst. Database de- velopers create the database based on the work of the
188 CHAPTER 6. SYSTEMS
database designer, setting up its structure and user inter- face, typically with the use of the database management system. This may be the same as the database designer, and they work alongside the database programmer, who creates the programs necessary for the database to be developed. Database administrators, or DBAs, man- age databases within an organization, maintaining them, monitoring user access to them, monitoring their perfor- mance, and performing backup. The users are the ones who actually “use” the database: they enter data into the database, update data within the database, and retrieve data from the database.[6]
6.3.2 Data Characteristics
3 states of data
Data is a collection of facts. It can be values, mea- surements, numbers, words, measurements, and observa- tions. Many businesses would not be as successful with- out data.[7] A data has a hierarchy; this hierarchy is a sys- tematic organization of data. Fields, records, and files are apart of the data organization. Product names or quanti- ties are the lowest level of the hierarchy, and the database is the highest level of the hierarchy.[8] Also, the data defi- nition consists of the following: name, data type, descrip- tion, and properties. This describes the properties that go into a database. If a computer user wants to look up all of the data definitions for a database, he or she would look up the data dictionary. A few key terms a computer user should be aware of, concerning data characteristics, con- sist of data field, record, file, and database. A data field contains a single fact of an entity. A record is a collec- tion of related fields. A file is an organization of related business records. The database is the place where files are integrated. The data characteristic key terms are essential to be aware of for businesses who use a database.
Data Organization
In order for a database to be efficient, its data must be organized in a fashion to make it easily and quickly ac- cessible. This is called data organization. Data orga- nization typically uses a primary key to identify where data is being stored. This allows for a specific record to
Server-web-database
be located efficiently. There are a few different meth- ods that databases use in order to store and retrieve data efficiently. The two most common are Indexed Method and Direct Method. Indexed Method is the method in which a database uses an index to keep track of where data is stored within it. An index is a table that has the primary key as well as the location information for that key. Index organization allows for records to be looked up quickly and retrieve information from the database. Di- rect organization is faster than index organization. This is due to it using the key field and a mathematical formula called hashing algorithm to find where specific records are physically stored in the database. These systems are much harder to develop. They pave the way for an inci- dent called collision, which happens when two or more records are assigned the same storage address. Some sys- tems use both methods. The key field will first indicate where the record is located in the table, and then the hash- ing algorithm is used to find where the data is physically stored on the storage medium.[9]
6.3. DATABASE 189
6.3.3 The Data Dictionary
A data dictionary is a read-only set of tables that contain all data definitions in a database. The table structures are non-editable without a password. A password is needed to view or edit a table. The definitions included in the database include all of the following: tables, views, in- dexes, clusters, synonyms, sequences, procedures, func- tions, packages, triggers, and more. Keep in mind; the data dictionary does not contain any of the information located in the data tables, only the data about the tables. This specific data about the tables is otherwise known as metadata. The database dictionary includes informa- tion regarding how much space has been taken up by the schema objects and the amount of space that is left. [10] The information that is included in the database must be organized before put into the data dictionary. Data mod- eling, or putting a descriptive name to each data object, must be done for each independent object. Once that is done, the relationship of the data is described, along with the description of type of data. Type of data can include defining the object as text or an image. Once that is com- pleted, the programmer must include a brief textual de- scription regarding the data. [11]
6.3.4 Data Security and Privacy
Public key encryption is one way to secure data.
Data security is a must-have, and is required by most in- dustry, business and legal mandates. Data security is what protects that data from being breached, so that the infor- mation it contains cannot be disclosed or leaked. Data se- curity also ensures the integrity of the data, meaning that no unauthorized changes can be made to data, data struc-
tures, configuration files, or logs. Data security programs can keep track of the files and monitor the transferring of data to prevent unauthorized access and stop any possible intrusions from occurring.[12]
Because technology has developed so much over the years, more and more actions are taking place over on- line through the internet, apps, or other networks. This has raised the issue of privacy, as many personal and sen- sitive information is often held in databases for many or- ganizations (hospitals, insurance companies, jobs, health care companies, etc.). To help solve this, privacy laws have been made to determine how companies and indi- viduals can have the ability to choose what information can be given to third parties and what cannot be given out. In the United States, different privacy laws have been passed for specific industries or situations. Some of these laws include the Children’s Online Privacy Protec- tion Act (COPPA), the Health Insurance Portability and Accountability Act (HIPPA), the Electronic Communi- cations Privacy Act (ECPA), and the Video Privacy Pro- tection Act.[13]
6.3.5 Classification of Databases
Single-User vs. Multiuser Database Systems
Database Server
Single-user database systems are located on one computer and they are designed for one user. They are used for per- sonal use and small businesses. Only one person can use
190 CHAPTER 6. SYSTEMS
the database at a time, so if one user is using the database the other users must wait until that user is done. The other kind is used for bigger businesses. It is a database that is accessed through a network. It is so more than one per- son can access and change the data in a system. Most use some kind of lock on the database so that there are no conflicts between people making changes. They can be on one computer or multiple computers.[14]
Client-Server and N-Tier Database Systems
Most multiuser database systems are client-server database systems. Basically client-server database sys- tems are servers that have resources for other computers. It is when the client part makes a service request from the server, which completes the request. The client is referred to as the front end and the database server is referred to as the back end.[15] Some of the client-server database systems have more than just the front end and the back end but also a middle part called a tier. These are referred to as n-tier database systems. In these databases the client and the database never communicate directly, all data is passed through the middle layer. The advantages of this database system is that the middle tier provides a layer of abstraction, that way you can change parts of the back end without having to modify parts of the front end. It is also a good way to separate responsibilities; they can also be more efficient.[16] Client Server Internet gives IT organization. They look into three specific technologies in the IT organization. They first act like clients and servers of course, they can access the internet as well to get into databases..etc. The final technology is to be able to create, view, use, modify, and delete applications. Software modules and hardware components are used to be able to actually perform functions. The client server connection is by two different modules, one acting as the client/server.
The two are able to communicate with messages. They can be sent whether the server is online or off. They are thus able to connect with a network. A network is a group of connected objects or people; the network is able to relay those messages to one another. The main use for a client server is to produce a useful application for the business’s needs. Client servers use middleware which is an important part that allows for applications on the client end to be able to reach the actual network and talk to the server. It is the basis that is in between the network and the application software. E-mails are a type of middleware since it is in between the network and the application.[17]
Centralized vs. Distributed Database Systems and Disk-Based vs. In-Memory Database Systems
Database Systems
Centralized database systems are all located on one com- puter. This can either be a server or mainframe com- puter. Distributed database systems share a network and the data is divided between several computers connected to that network. An advantage of a centralized database system is that all information is in one place. The dis- advantage may be that a bottleneck might occur. Hav- ing all information on one computer can make it easier to some users, but difficult for others who want to access the files. One advantage of distributed database systems is that the database can be accessed using any computer on the network even if all the information is not on one computer. This is the preferred type of system to use for databases, because information can be easily found. It also ensures that all data will not be lost, if using the distributed database system over the centralized system. Because of the recent advances in technology, using the “cloud” is another way to store database information over the Internet for an easy way of storage. This concept goes hand in hand with disk-based and in-memory database systems. Most databases are stored on conventional hard drives in computers today, but recently many are switch- ing to in-memory databases. This can hold all data on the main memory of the computer. This creates faster per- formances than it would if using the disk-based system.
In-Memory Database
An in-memory database (IMDB) is a database whose data is stored in main memory to facilitate faster re- sponse times.[18] In-memory databases are also some- times referred to as main memory database systems, or MMDBs, and have become more popular in recent years
6.3. DATABASE 191
Main Oracle Memory Areas
for handing High-Performance Computing (HPC) and Big Data applications. Applications, such as those run- ning telecommunications network equipment and mobile advertising networks, often use main-memory databases. Three developments in recent years have made in- memory analytics increasingly feasible: 64-bit comput- ing, multi-core servers and lower RAM prices.[19] Source is loaded into system memory in a compressed, non- relational format. In-memory databases streamline the work involved in processing queries which provides faster and more predictable performance than disk(as access times and database requests are typically considerably faster when system memory is used as opposed to disk storage, particularly hard drive storage.). Main memory databases are faster than disk-optimized databases since the internal optimization algorithms are simpler and exe- cute fewer CPU instructions. Another advantage of in- memory databases comes into play when transactional data and analysis data is stored in the same database. It’s easier to carry out ad-hoc analysis as all of the data needed to analyze a business case is written to a single database.[20]
6.3.6 Database Models
Relational Database Model
Relational database management systems are important because they take several related tables and combine them in the least complex way that is possible. Essentially the RDBMS takes these smaller, less compact, tables and finds ways to relate them to one another based on singular variables to avoid repetition as much as possible. When creating such a database there are four main questions to ask: what is the point of this database? what information needs to be included in this database? which variables should be placed in which table to make the end result the least tangled/complicated? and how should this table be formatted? Once all those things are completed, one could use a program such as Microsoft Office’s Access[21]
to create a query by choosing specific related fields to dis- play and organize. After this, one could use the query to generate a report which is essentially used to import the selected information into a singular database that would be easier to read through and find information from.
A database table
Relational database comes into play when an asset track- ing database is needed, and spreadsheets are too large to use for the particular data. After the design of your new database, including the fields, data types, primary keys, and foreign keys, is finished, the next step is to actually go ahead and create the corresponding table for the database. The very first step to create a relational database is to cre- ate and name a new database file, which will contain all tables and objects included in the database. Next, using the table structure formed in the “design” phase of the process, each table in the database is created. And fi- nally, once that table structure is complete, the last step is to enter the data into the tables, and relate different tables to each other as needed. In Microsoft Access, a table can be created under the Design View by entering each field name and specifying the data type and other properties as needed. However, if you wish to use your old or existing data in the new database, a process called data migration takes place by transferring the data from the old files to the new. Additionally, Design View also lets you make various sorts of edits in the form if you wish to have a specific layout or design—such as chang- ing the form color, font size, the placement of the fields, or adding a heading, etc. [22]
Star Schema Model
Star schema database
Star schema is one of the simplest database models and is commonly used as a model for relational data warehouses and multidimensional databases. It consists entirely of fact tables and dimension tables. Fact tables are an event or entity such as a sale and a dimension table consists of
192 CHAPTER 6. SYSTEMS
details about that event such as date, place, speed of deliv- ery, etc. For example, a geography dimension table can be used to describe location data, such as country, state, or city. In a star schema, a fact table is surrounded by numerous dimensions that branch out, creating an image similar to a star. One of the advantages of a star schema model is that it is compatible with Online Analytical Pro- cessing (OLAP) which allows for data mining of specific information from different points of view. For example, a user can view the sales from a specific item at any spe- cific time in the past.[23] One of the disadvantages of the star schema model is that it is a simplistic model so it is not capable of creating complex relational analytics. Star schemas are also denormalized so it is possible for redun- dancies to occur within the database.[24]
Types of Relationships
League Team
One-to-many relationship (Leagues related to teams in the league)
There are three basic types of relationships among enti- ties. These three types include: one-to-one, one-to-many, and many-to-many. In a one to one relationship every row in one table is linked to one specific row in another table. This means that there must be exactly as many rows in the first table as in the second table. This type of relationship isn’t very common due to the fact that there isn’t always a benefit to the design of a database. There is no benefit to the design because if the data is directly related it would make sense to have all the data in one table. One way that one-to-one relationships could be beneficial is if some of the data is needed, but isn’t used often. The data that isn’t used often could be stored separately, and away from the more important data.[25] One-to-many relationships allow each row in a table to be related to many rows in another table. This type of relationship is beneficial to a database due to the fact that you can reference frequently used data in many different tables by only entering it into one mas- ter table. Usually, the number of rows in the first table would be less than the number of rows in a second, third, forth, and so on, table. One-to-many relationships are of- ten used in libraries. For example, names of authors in one table could correspond with the books each author has written in different tables.[26]
Hierarchical and Network Database Models
The hierarchical model is the oldest database models. It organizes date in a tree-like structure, using parent and child data segments. For example, it begins at the top of the tree with a single root. That stems into a lower level
Database models
segment, which connects to other subordinate segments after. This is used to model one-to-many relationships. A disadvantage of using this model is that it requires data to be stored repetitively in multiple levels. This causes the database to function very slowly because it can be searching for information in lower levels as well. The net- work model uses a set structure. A set is comprised of an owner record type, a set name, and a member record type. This type of model shows many-to-many relation- ships. Parents can have multiple children, and children can have multiple parents. Both of these model types are outdated and no longer used for building new database ap- plications. They are often less flexible than other model types. [27]
Also, all paths for accessing the data must be planned ahead of time and cannot easily be changed. Some places you might still see the hierarchical model might be in large systems that use high-volume transaction process- ing, like banks or insurance companies.
Object-Oriented Database Models
OODBMSs, like this abstract statue, are more difficult to compre- hend initially while ultimately promising greater rewards.
Whereas other database models can only store conven- tional data (such as dates, numbers, and text), the object-
6.3. DATABASE 193
oriented database management system (OODBMS) is far more abstract. In an OODBMS, you can store pretty much any kind of data you desire, along with the methods to be used with that data. To retrieve this more complex and varied data, the user sends queries written in object query language(OQL) which is an object-oriented version of SQL. OODBMSs are becoming increasingly prevalent because of the higher demands of computer users today. However, as is the case with any new technology, there is some resistance because of the downsides of OODBMSs.
Cell Diagram for OOBDMS
One downside is how editing an OODBMS based appli- cation is more time consuming because changes have to be made to the other classes in the application that inter- act with instances of the parent class, versus an RDBMS system where edits can typically be independent of the parent application.[28] This is very time consuming and that means a lot of money has to be spent on making changes to the object-oriented database management sys- tem. Many companies in the business world have certain budgets set aside for the information department, which includes the database system used for the company, and the OODBMS is very costly. Another disadvantage for the OODBMS is the lack of support for security and views. The user of an OOBDMS cannot grant individu- als’ access to certain objects or classes within the system, which either means the individual wouldn’t be allowed to see the system at all or that they would get access to every- thing within the system, something businesses might not like. Also, the OOBDMSs do not contain a view mech- anism, which is a disadvantage for employees who like to see their work and also to make sure everything they put in is correct. Two more disadvantages of OOBDMSs that go hand in hand is the lack of standards for the sys- tem and the fact that there is no universal data model. Without standards for the system, the cleanliness of the system can be dragged down and it could be hard to use. Many people like when something is universal because then they know what is right and wrong, something that cannot see with the OODBMS.[29] Even with the extra difficulties, many important clients continue to operate using a OODBMS, one big example being Chicago Stock Exchange, which uses the system to manage stock trades. After looking at the types of database models, there are 4
Tuple
Relation
Attribute
Relational database terms
steps involved with designing a relational database. The first step in designing a relational database is to identify the purpose of the database and the activities that it will be used for. These activities can range from keeping track of rental properties, students grades, customer orders, or inventory. Databases are used in a wide variety of ways and knowing what you will use your database for will help you create your database and optimize its use. In know- ing what purpose your database will serve, you will be able to determine the data (fields) that needs to be in- cluded in the database, then the fields can be organized into tables. It is good to group fields that logically belong together. Next look at the table structure and ensure that all fields are represented and in the proper table. Look to see if there is any redundancy in the data, that way you can restructure fields in order to minimize that redun- dancy. Lastly, finalize the structure of each table, listing each field’s name, type, size and so on and selecting a pri- mary key (data definition). This procedure will assist you in create a database that will suit your needs and provide the information you request.[30]
6.3.7 Databases on the Web
Web Databases in Use
There are many ways Web databases can be used. The most obvious way is the retrieval of information. Web databases provide a means for users to access the mas- sive amount of information the Web has to offer, and this is made possible, in one way, by the use of search sites where databases provide links for the user. Other personal uses for databases include the storage of email addresses, telephone numbers, and other information for one who might create a site for friends and family.[31] On the business end, Web databases allow businesses to cre- ate “website polls, feedback forms, and client/customer inventory lists.”[32] This is a vital function that both large and small businesses can take advantage of to suite their needs. One, specific example relating to business-use of Web databases is the management of e-commerce-related activities. Here databases are used to provide informa- tion like pictures and pricing for products as well as order information and other necessary functions to enable effi- cient and reliable business transactions. Another feature of Web databases is their ability to display dynamic Web
194 CHAPTER 6. SYSTEMS
Amazon is just one of many companies that utilize Web databases for their business needs
pages. These pages display information that changes de- pending on the input of the user, like a B2C site showing pages related to the interests of the consumer based on his or her past acivities. From personal to business appli- cations, Web databases are a vital part of addressing the tasks associated with Web-related activity.
This advertisement would be targeted towards someone involved with universities.
Not only are websites becoming more and more person- alized for the viewer, but the advertisements on the web page are as well. Companies including major search en- gine Google deliver targeted ads towards certain con- tent and audiences. One method is contextual targeting, which analyzes keywords, word frequency, and link struc- tures to determine what ads would match the content of the page. Placement targeting uses specific ads chosen by advertisers on certain web pages that are supposed to match what the viewer’s other interests may be and what other kinds of products they have to offer. Similar to this is interest-based advertising, which places advertise- ments relevant to certain interests on web pages that are commonly viewed by people with that similar interest. Google offers a program that people can use in order to set their interests so that ads are tailored towards their selections. Lastly, language targeting determines the pri- mary language of the page and ensures that the advertise- ments shown will be in the same language. Advertise- ments would not work very well if the viewer could not even read what the product was that they were advertis- ing! All of this information is placed into Google’s ad search database which processes the information and en-
sures that the advertisement on your screen is going to be relevant to you.[33]
Middleware
Database Layout
This is a computer software that provides services to soft- ware applications beyond those available from the operat- ing system. It is software that connects two otherwise sep- arate applications, which can resemble “software glue.” For example, there are a number of middleware products that link a database system to a Web server. This pro- vides the user to be able to receive data from the data base by using forms that are displayed on a Web browser, and it enables the Web server to return dynamic Web pages based on the user’s requests and profile. As stated previ- ously, the term middleware is used to describe separate products that serve as the glue between two applications. It is, therefore, distinct from import and export features that may be built into one of the applications. It is some- times called plumbing because it connects two sides of an application and passes data between them. Distributed computing system middleware can loosely be divided into two categories. These categories are those who provide human-time services and those that perform in machine- time. This latter middleware is somewhat standardized through the Service Availability Forum and is commonly used in complex, embedded systems within telecom, de- fense and aerospace industries. [34]
How Web Databases Work
In our technological world, we use web-based database requests on a daily basis. We are constantly visiting web pages, clicking on links and using the menu to navigate us through our activity on that page. Using middleware, the web server passes a request on to a database query and the information is stored and passed along to the database server. The database server then uses this information to direct the page to where it was intended to go. CGI Script is another way information is passed along. They use instructions via a programming language and accept and return the websites data to the user. Active server pages are yet another example of scripts used commonly
6.3. DATABASE 195
Example of PHP Script
on websites. They are very similar to CGI Scripts, yet they are exclusive because they almost always use VBS script or Java script. PHP Hypertext processor is a lan- guage that is becoming more and more popular everyday. This script is extremely similar to CGI scripts and active server pages yet are more highly compatible with other programs. The script functions using PHP tags and html codes to get their job done. These scripts are just some examples of what is used today and how information in transmitted on a web server.[35]
CGI Scripts
a CGI (common gateway interface) script is a set of in- structions written in a programming language (such as C, Perl, Java, or Visual Basic) and designed to accept data from and return data to a Web page visitor. On very busy sites, CGI can slow down server response time sig- nificantly because it processes each request individually. The usual placement of a CGI script is in the remote web servers cgi-bin directory, but the exact location of this directory is determined by the web administrator for that machine.[36]
Active Server Pages
Active Server Pages (ASPs), Microsoft’s first server-side script engine for dynamically generated Web pages, have the extension .asp. ASPs work similarly to Web pages uti- lizing CGI scripts, but the code to tie the database to the Web site is typically written in JavaScript or VBScript.
PHP Scripts
PHP (PHP Hypertext Preprocessor) is a scripting lan- guage that is increasingly being used to create dynamic Web pages. Free to download and use,[37] It uses code similar to Perl or C++ that is inserted into the HTML code of a Web page using special PHP tags. Although PHP scripts perform tasks similar to CGI and ASPs, they
PHP Elephpant mascot
have the advantage of high compatibility with many types of databases.
6.3.8 Review
Terms and definitions [38]
attribute A characteristic of an entity. centralized database system A database system in which all of the data used by the system is located on a single computer. client-server database system A database system where the database is located on a server and accessed by client devices. column In a database, a field. data definition The process of describing the properties of data that is to be included in a database table. data dictionary The repository of all data definitions in a database. data integrity The accuracy of data. data privacy' Protecting the privacy of the data located in a database. data security Protecting the data located in a database against destruction and misuse. data validation The process of ensuring that data entered into a database is valid (matches the data definition). database A collection of related data that is stored in a manner enabling information to be retrieved as needed; in a relational database, a collection of related tables. database management system (DBMS) A type of software program used to create, maintain, and access databases. direct organization A method of arranging data on a storage medium that uses hashing to specify the exact storage location. distributed database system A database system in which the data used by the system is located on multiple computers that are connected via a network.
196 CHAPTER 6. SYSTEMS
entity Something (such as a person, object, or event) that is important to a business or organization; typically be- comes a database table in a database system for that busi- ness or organization. field A single category of data to be stored in a database, such as customer names or employee telephone numbers. Also called a column. form A formatted way of viewing and editing a table in a database. hybrid XML/relational database A type of database system that can store and retrieve both XML data and relational data. in-memory database (IMDB) A database that stores all data in memory instead of on a hard drive. index A small table containing a primary key and the lo- cation of the record belonging to that key; used to locate records in a database. indexed organization A method for organizing data on a storage medium or in a database that uses an index to specify the exact storage location. metadata Data about data, such as the data contained in a data dictionary. middleware Software used to connect two otherwise sep- arate applications, such as a Web server and a database management system. multidimensional database (MDDB) A type of database designed to be used with data warehousing. multiuser database system A database designed to be accessed by multiple users. normalization The process of evaluating and correcting the structure of a database table to minimize data redun- dancy. object-oriented database management system (OODBMS)' A type of database system in which multiple types of data are stored as objects along with their related code. primary key A specific field in a database table that uniquely identifies the records in that table. query A request to see information from a database that matches specific criteria. record A collection of related fields in a database. Also called a row. relational database management system (RDBMS) A type of database system in which data is stored in tables related by common fields; the most widely used database model today. report A formatted way of looking at information re- trieved from a database table or the results of a query. row In a database, a record. single-user database system A database located on a
single computer and designed to be accessed by a single user. structured query language (SQL) A popular query language standard for information retrieval in relational databases. table In a relational database, a collection of related records or rows. Questions 1. Match each term with its example: A. When the database does not allow a user to enter a letter in a phone number field. B. Requiring users to log on to a database system via a fingerprint reader. C. Assigning a field the property of “required.” i. Data definition ii. Data integrity iii. Data security Fill in the blank
2. In a student information database, Name would be considered a(n) _______________, while all of Jennifer Mitchell’s information would be a(n)___________. 3. Data _______ refers to accuracy of data. 4. When _____ organization is used, a hashing procedure determines where data is stored. 5. The term front end and back end refer to ______ database systems True or False
6. Normalization is used to minimize data redundancy. 7. In a relational database, more than one table can be included in a database. 8. Using usernames and passwords is a data validation technique. 9. The network database model is the most widely used model today. 10. Dynamic Web pages commonly use databases. Answers [39]
1. A. ii B. iii. C. i. 2. field or column; row or record 3. integrity 4. direct 5. client-server 6. True 7. True 8. False 9. False
6.3. DATABASE 197
10. True
6.3.9 References [1] http://www.usg.edu/galileo/skills/unit04/primer04_01.
phtml
[2] http://ecomputernotes.com/ fundamental/what-is-a-database/ advantages-and-disadvantages-of-dbms
[3] http://products.office.com/en-us/excel
[4] https://support.office.com/en-us/article/ Training-courses-for-Access-2013-a4bd10ea-d5f4-40c5-8b37-d254561f8bce? ui=en-US&rs=en-US&ad=US
[5] http://smallbusiness.chron.com/ importance-inventory-databases-retail-40269.html
[6] Understanding Computers: Today and Tomorrow - 14th Edition Comprehensive
[7] http://www.mathsisfun.com/data/data.html
[8] http://technet.microsoft.com/en-us/library/ee633737. aspx
[9] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013946
[10] https://docs.oracle.com/html/A96524_01/c05dicti.htm
[11] http://searchsoa.techtarget.com/definition/ data-dictionary
[12] http://www-01.ibm.com/software/data/security-privacy/
[13] http://searchcio.techtarget.com/definition/ data-privacy-information-privacy
[14] http://www.slideshare.net/raminder90/ single-user-vs-multi-user-databases
[15] http://searchnetworking.techtarget.com/definition/ client-server
[16] http://databases.about.com/od/specificproducts/a/ architectures.htm
[17] http://www.networkcomputing.com/netdesign/ 1005part1a.html
[18] http://whatis.techtarget.com/definition/ in-memory-database
[19] http://whatis.techtarget.com/definition/ in-memory-database
[20] http://www.gft.com/etc/medialib/2009/downloads/ techreports/2012.Par.0003.File.tmp/gft_techreport_ inmemorydatabases.pdf
[21] http://office.microsoft.com/en-us/access-help/ create-a-query-based-on-multiple-tables-HA010096275. aspx
[22] http://office.microsoft.com/en-us/access-help/ create-tables-RZ101772997.aspx?section=2
[23] http://searchdatamanagement.techtarget.com/definition/ OLAP
[24] http://searchdatamanagement.techtarget.com/definition/ star-schema
[25] http://www.databaseprimer.com/pages/relationship_ 1to1/
[26] http://www.databaseprimer.com/pages/relationship_ 1tox/
[27] http://wps.prenhall.com/wps/media/objects/14071/ 14409392/Learning_Tracks/Ess10_CH05_LT3_ Hierarchical_and_Network_Data_Models.pdf
[28] http://slashdot.org/story/01/05/03/1434242/ why-arent-you-using-an-oodms
[29] http://www.scribd.com/doc/6142698/oodbms
[30] http://code.tutsplus.com/tutorials/ relational-databases-for-dummies--net-30244
[31] http://www.htmlgoodies.com/primers/ database/article.php/3478121/ To-Use-or-Not-to-Use-a-Database-That-is-the-Question. htm
[32] http://www.ehow.com/info_8219542_database.html
[33] https://support.google.com/adsense/answer/9713?hl=en
[34] https://docs.djangoproject.com/en/1.3/topics/http/ middleware/
[35] http://guide.netfronts.com/Database-PHP-ASP/adding_ dynamic_web_content.html
[36] http://snowwhite.it.brighton.ac.uk/staff/mas/mas/ courses/html/html3.html
[37] http://www.w3schools.com/php/php_intro.asp
[38] http://coursemate.cengage.com/CPReader/View/ 9781133114598/default.aspx?eISBN=9781133114598# 66897dee-5c5a-4b7d-8a74-0eac7f4de56c
[39] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013946
Chapter 7
Computers and Society
7.1 Computer Security
7.1.1 Hardware Loss or Damage
Brokenlaptop
Hardware loss is inevitable. With so many people want- ing the latest and greatest, you could imagine that others might get jealous, or desperate. Hardware theft is promi- nent and a large issue in the world. For whatever reason, peoples personal possessions are stolen. They could be stolen for valuable information, or just to pawn off the items for some quick money. With 1.6 million phones being stolen, this is an issue that needs to be dealt with.[1] Hardware loss is not the only way someone could lose their laptop or Android.[2] Hardware damage can render any of the latest and greatest useless. Whether is was a clogged fan, spilled water, or dropping it on the floor. When that moment arises, you know that it could all be gone within a matter of seconds. System Failure is the complete malfunction of a com- puter system. This may be due to hardware failure, se- vere issues with certain software on the computer, or even a computer virus. Frequently, system failure will cause the computer to freeze, reboot, or stop functioning al-
together and the repercussions of such an event can be devastating for a business. The result is often either the loss of important data, delays in the transfer of impor- tant information, and in some cases even the inability to function properly. An easy example of a system failure can be seen in the lawsuit California issued against SAP Public Services Inc.[3] California’s payroll was affected by SAP’s software solutions which cost the people of the state of California $250 million as well as delaying the paychecks of numerous employees of the California gov- ernment. In this case, there was no loss of data but rather delays in the transfer of information as well as the cor- ruption of it. Some checks were overpaid, others were underpaid. In some instances the incorrect spouses were paid for child support which could have culminated in the court intervening for an unpaid mother or father. Insur- ance benefits were also denied to others because of the system’s inability to transmit data regarding medical de- ductions. It can be easily seen how a system failure can affect multiple people on many levels with a case like this, and how quickly the ability to function properly can be the result. The corruption of data and the inability to transfer it swiftly produced one of the largest debacles in govern- ment at the state level in recent times. Along with hardware loss there are also ways to prevent and deal with unfortunate situations along these lines. Knowing about computer security can prevent many in- cidents from occurring that could result in the loss of per- sonal information as well as the money you have put into your computer. The first tool for containing computer se- curity can simply be just making sure what you have on your computer is information that could not damage your life if it was lost. But we do not live in a perfect world, and sometimes things slip and a credit card statement or a password to important information can be released. In this case, you should take all steps to prepare yourself to deal with that situation before it is too late. Software pro- grams are available and free, however, such as “Adeona” which can be installed very easily onto your desktop. This program tracks the location of laptops, and can even take pictures of the perpetrator if you have a Mac. There is a recovery tool which can send you a text file of the infor- mation contained about the theft of a laptop, which can then be taken to the police to hopefully resolve the issue
198
7.1. COMPUTER SECURITY 199
Computer locked
and bring liberty to the situation. There are other pro- grams like this are available, as well as alarms that can be put on your laptop if someone unplugs it or puts in a wrong password. Steps like this can be taken to pre- vent loss of your computer and help keep your informa- tion safe.[4]
Surge Suppressor
As discussed before, hardware loss is a very unfortunate situation that can result in the loss of important data. The loss of data can be influenced by many things, including power shortages. A way an individual can protect their data is by using different devices that are available to pur- chase and use with their device. Surge suppressors pro- vide an individual with the assurance that their hardware
will be protected from damage in case there are electri- cal fluctuations. Surge suppressors work in a very simple way with few steps. The device protects an individual’s hardware by channeling the extra voltage into the outlet’s grounding wire, preventing the extra voltage from going to the device. However, the device still enables the nor- mal amount of voltage to pass through to the device. An individual can also protect their hardware by investing in a uninterruptable power supplier, otherwise known as a UPS. These devices provide continuous power to the de- vice if the power were to go out for a period of time. Another way that enables individuals to protect their data is by backing up their data. It is important for both busi- nesses, as well as individuals to backup their data. There are multiple ways individuals can do so. One option that is available is to consider remote locations to store data, in case there is system failure at a main location. Another option is to store data through an internet “cloud” system. Overall, it is very important to backup data, regardless if an individual is convinced their data will not get stolen or destroyed. [5]
Locks
WD disk with kensington
One form of physical security that is available on most electronics is the “Kensington Lock” or “Kensington Se- curity Slot” (a.k.a. the “K-slot”). It’s ubiquity amongst electronics has allowed it to become an industry standard on everything from PC cases, to laptops, to monitors. This type of anti-theft protection was patented in 1999 by the company Kryptonite. [6] This security measure is most often used in the scenario of a coffee shop, as if someone was going to run off with a laptop, it would add another level of complexity, making the laptop cumber- some and also raise suspicion in the eyes of observers of a theft. There has not been any physical locking mecha- nism as common as this to date.
Mobile Device Management
The management of mobile devices is very common within institutions such as schools or companies that have mobile devices for their students or employees. The man- agement of mobile devices can apply to many different situations. For example, it can apply to the management of devices owned by the institution. It may also apply
200 CHAPTER 7. COMPUTERS AND SOCIETY
Many schools are now switching from textbooks to tablets so the use of mobile device management has grown
to the management of devices that are connected to the wireless network of the institution. Usually, the IT de- partment of the institution utilizes a third-party software that allows certain restrictions to be placed on particular mobile devices whether it be phones, tablets, or laptops.[7] Some popular softwares include AirWatch which is dis- tributed by VMWare [8] and maas360 which is distributed by IBM.[9] Apple also has their own device management software that is integrated into iOS devices.[10] Some restrictions that may be implemented by mobile device management include the restriction of certain websites or applications. IT may also completely block the ability to download applications or surf the Internet on the de- vices. Although restriction to apps can be implemented, the management of mobile devices also includes the in- stalling of apps onto devices. For example, if an entire company shares information and files through an applica- tion such as DropBox, then the IT department may simply install the application onto every device. This also allows for IT to update the app when needed instead of relying on the individual users to download the update. Another use of mobile device management is the restriction of fea- tures on the phone. For example, IT may restrict access to the camera to avoid pictures being taken within the workplace.[11]
Ruggedized Devices
Ruggedized devices are devices designed to withstand large amounts of physical abuse. There are two differ- ent classifications of ruggedized devices. Semi-rugged devices are able to withstand things like rain and dust, while ultra-rugged devices are able to withstand drops onto hard surfaces. These designs can also protect against accidental beverage spills and small burns. Ruggedized devices are often used by people who work outdoors. For example, construction workers, police officers, fire- fighters, and military personnel will often use ruggedized devices. Construction workers often use weatherproof stereos near worksites that prevent dust from getting in. Police officers will often have rugged laptops in their ve-
Panasonic Toughbook
hicles due to the possibility of extreme weather during investigations. Firefighters need their heart rate monitors and communication devices protected from high temper- atures and the possibility of stray flames. Military person- nel use rugged radios and video cameras during combat. Laptops and phones are among the most popular types of rugged devices.[12] Panasonic, an electronics company, produces a bestselling rugged laptop called a Toughbook. A Toughbook is usually very bulky and has a longer bat- tery life compared to regular laptops.[13] Samsung pro- duces a popular rugged cell phone called the Galaxy S5 Active. The Galaxy S5 Active was engineered for active lifestyles. It is water-resistant and shock-resistant.[14]
Mobile Devices As mobile devices become more com- mon place, new cases and mean of protecting them are becoming more and more common. This is especially prevalent for smart phones. Smart phone are a substan- tial investment, and as they are used quite often, there are many opportunities for the device to be dropped, soaked, or crushed. As people want to protect their device, cases are found on most phones. They can be quite simple, just a piece of formed plastic, or quite advanced, with some completely sealing off the phone from scratches, dust, and full water immersion. Phones are not alone re- garding protective cases. As tablets are used more and more, special cases are being made for their protection as well. Some cases protect the device, and provide a mounting point to use on steering wheels, dashboard, or vehicle windows. Many of the mounts are removable so the device can go from a navigation aid back to a phone in seconds.[15] Cases usually have some kind of screen pro- tector to protect against scratches and sun glare. These protectors are thin pieces of plastic, which stick to the screen of the device. The thin plastic allows for the con-
7.1. COMPUTER SECURITY 201
tinued use of the touch screen, and provides protection. As the plastic gets scratched, it can be replaced.
Front view of iPad Mini in a Pivot Case
The rear of the case with mounting hardware in view.
7.1.2 Encryption
Ordinary hard drives like these may in time be replaced by self- encrypting ones.
As discussed previously in this Wikibook, it is very im- portant to encrypt one’s data and prevent it from being accessed by outside individuals. Two specific encryp- tion measures are full-disk encryption (FDE) and self- encrypting hard drives. Full-disk encryption consists
of encrypting all of the data on a storage medium, not just the individual files. Self-encrypting hard drives are ones that automatically encrypt stored data without the user having to manually do anything to encrypt it. The encryption occurs completely automatically and invisibly to the user from the moment the hard drive is manufac- tured, and they provide full-disk encryption. The encryp- tion cannot be turned off and does not interrupt the work flow of the user. These devices protect data even when employees violate company policy by turning off network security features. SEDs are still rather expensive, so they are not as commonplace now as they might be in the future if costs decrease. They only started shipping in 2009, so it is likely that in the future, they will become cheaper and more common, increasing security standards and helping to keep the data of individual users, compa- nies and corporations, and governmental agencies inac- cessible to and safe from outside forces and hackers.[16]
7.1.3 Software Piracy
Software piracy, a common name for file sharing, is the illegal copying and distribution of software. It is unau- thorized by the copyright holder of the software, and it is a widespread recurrence in the computer era of to- day. If one purchases a software, he or she is not the owner of that particular software, but he or she is only licensed to the software. This means he or she can make copies, but for their own use only, or as stated in the End User License Agreement. In the United States and other countries, it is illegal to make copies of software, movies, CDs, etc., and then redistribute these copies to someone. In countries such as Sweden, copyright law restricts peo- ple to non-commercial sharing. A few common types of software piracy are the following: counterfeit software, OEM unbundling, soft lifting, hard disk loading, cor- porate software piracy, and Internet software piracy.[17] Software piracy is debated currently, with one side stat- ing that it has a negative effect on the economy because it reduces the funding for ongoing developmental efforts, and it prevents users from getting high quality technical support and product updates, while the pro-sharing argu- ment states that people should be allowed to share as they wish, and the financial benefit of corporations granted by Intellectual Property Law is unjust. However, BSA is a common software who is a global organization that forms to advance free, and open world transfer for legitimate software by advocating strong intellectual property pro- tection. The BSA works with many software and com- mercial companies to stop file sharing. What some people may not realize is that after purchasing software, they do not own the software, but have instead purchased a license to use the software. Upon purchasing software, the purchaser has agreed to certain limitations concerning the software, such as only using the software on one computer. The purchaser also agrees to not make any illegal copies or install it on a computer other than
202 CHAPTER 7. COMPUTERS AND SOCIETY
Piracy cartoon
their own. Any illegal act concerning misuse or dupli- cation of software is known as software piracy. There are many ways to prevent and protect against software piracy. One tip is to better educate consumers and busi- nesses of the threat of piracy. Some consumers may be purchasing pirated material without even having knowl- edge of it. It is important for people to use credible sources when purchasing software. Also, it may help to make people more aware of the damage that using pi- rated material can cause. According to the BSA, (Busi- ness Software Alliance) revenue loss in software compa- nies in 2008 reached fifty billion dollars. According to the BSA Global Software Piracy study, fifty seven percent of the Worlds computer users admitted to using pirated soft- ware. Whether it is the unauthorized installation of a pro- gram onto a computer, or the illegal distribution of soft- ware, it is considered software piracy and is punishable by the law. Perhaps educating people on the large deficits software companies experience due to piracy would make the act less prevalent.[18]
7.1.4 Electronic Profiling, Privacy Policy and Spam
Marketing Databases
Different Ways to Use Psychographic Data in Online Marketing
The most types of direct marketing require a database with customer information. With this information the seller can design communication taking into account the individual characteristics of prospective customers, both private individuals and companies. The database is be- ing formed for a considerable time, or being purchased from specialized companies, supplying various special- ized databases. Marketing databases - is the process of creation, maintenance and using of customer information for the purpose of contacting the latter and do the busi- ness. Along with information about the actual customer, has used the services of the company, they should be col- lected information about potential consumers. Databases should be constantly improved based on the accumula- tion of information about the value of the consumer - the frequency and the value of purchases made by him. This method of maintaining the database using the rank- ing values consumer received the name of the method RFM (Recency, Frequency, and Monetary) Value of Purchases. Other information required to replenish the database may include the payment method of purchase, Buyer, the character they buy goods or services. Mar- keting Database will be most effective if it is focused on building relationships. Direct marketing does not have to be like a “single shot”, which are intended to entice buy- ers to a rapid response before they become distrustful. Building relationships with customers should be based on their life values (method CLV). Only in this case they will be long-term and will bring tangible benefits. However, before you start to build a relationship, you need to care- fully select the most prospective buyers who can make the biggest contribution to the volume of sales made. To se- lect these buyers, marketers often develop consumer pro- files. Building relationships with customers by CLV is impossible without a comprehensive study of the charac- teristics and properties of consumer goods, as well as de- termine the degree of customer satisfaction and the avail- ability of personalized information. However, with the
7.1. COMPUTER SECURITY 203
information is too personal should be very careful, as their use in communication can lead to a negative reaction from consumers.[19]
Electronic Profiling
Amazon uses electronic profiling to make suggestions as to what people might like to purchase
Electronic profiling is when marketing companies collect information about an individual. They can get the infor- mation from purchases that a person makes on the Inter- net, as well as public information like births, marriages, vehicle registrations, etc. An electronic profile usually consists of a person’s name, age, telephone number, mar- ital status, number and age of children, spending habits, and previous purchases. This is how online websites like Amazon can make suggestions of what someone might want to buy.[20] That information can then be sold to com- panies who may ask for it for marketing purposes. Most businesses that collect personal information have a pri- vacy policy, which will tell you how your personal infor- mation is going to be used and as long as the business follows what they say in their privacy policy it is legal for them to sell your personal information. The prob- lem with this is that sometimes privacy policies can be unclear in their intentions and they can be hard to deci- pher. Companies may also change their privacy policy often and people don’t take the time to read through it. Electronic profiling also leads to behavioral advertising, where someone might see advertisements about things in their area or about people that are around the same age and gender as them. It is kind of crazy that the computer knows that about someone and then can apply it to the things that person looks at.[21]
The Direct Marketing Association (DMA) is the main advocator of electronic profiling. Electronic profiling has become an entire industry, thus the DMA voices
People’s Information is used for Marketing Databases.
against privacy policies that would keep consumer’s in- formation from being used for marketing and advertis- ing. Profiling data has been sold long before the inter- net, however, online tracking has made it develop even more. While most of this information is sold for mar- keting or spam purposes, it can also be used for individ- ual use. Websites such as whitepages.com and switch- board.com allow anyone to search for a person’s name and city, and results show up giving personal informa- tion including their house address, phone number, email address, and relatives. There are ways to avoid having your information out in the open. First of all, there are some common sense rules such as limiting how many or- ganizations or stores information is given to, not giving out an email address when it is optional, and not giving out your social security number. According to the Elec- tronic Privacy Information Center (EPIC), other ways to self-defend your privacy include the following: reading privacy policies, no matter how tedious or long it may be; being aware of when companies change their privacy policies, as many companies change them often; opting- out from pre-approved credit companies and from infor- mation sharing; making sure that when you opt-out from these things, that the permanent box is selected or else many times you can be re-added after a period of time; requesting a “temporary” change of address when filling out a Postal Service Change of Address Card so that the information does end up in any database and thus cannot end up in a profiling database; and lastly, be careful of cat- alogue merchants and be sure to ask that they do not sell your information; never buy anything from a telemarketer call or an infomercial, as they almost always are putting your information on an automatic “responder list”. It is always good to be cautious when giving information out, no matter what organization or personal is receiving it.[22]
204 CHAPTER 7. COMPUTERS AND SOCIETY
Privacy Policy
25/06/2012 Privacy Policy « CubeMe
1/2cubeme.com/blog/privacy/
HOME ADS ARCHITECTURE ART FASHION FOOD FURNITURE GADGETS GREEN LIFE STYLE MOBILITY MUSIC TECH TRAVEL
Privacy Policy This privacy statement covers all of the CubeMe! Media Sites. Please read this statement carefully before accessing CubeMe! Media Sites. Your use of CubeMe! Media Sites indicates your agreement to abide by the Terms in effect.
Information Collection CubeMe! Media is the sole owner of the information collected on the CubeMe! Media Sites. CubeMe! Media may collect information from its users at several different points on the CubeMe! Media Sites.
Comments In order to enhance their use of the CubeMe! Media Sites, users can choose to leave comments on particular articles of interest. To leave a comment, users must submit information including a valid email address. CubeMe! Media uses this information to screen out users who leave comments prohibited by our terms and conditions of use, and will not pass this information to any other organization.
Mailing List CubeMe! Media may launch a mailing list for some or all of the CubeMe! Media Sites. In order to sign up to receive regular emails from a site’s mailing list, users must submit information including a valid email address and demographic information such as location and interests. This information will be used in aggregate form only in order to assess general user interest in various internal and third party products and services, and your personal and contact information will not be passed to any other organization. Users who choose to sign up for a mailing list will receive regular emails from the site, including new articles added to the site as well as emails from third party site sponsors. If you do not wish to receive emails from third party advertisers, do not sign up for the mailing list.
Discussion Group and Cookies In order to further enhance the user experience, CubeMe! Media may launch a discussion board service on some or all of the CubeMe! Media Sites where users can discuss common topics of interest. Users will have the option of signing up for this service, and to do so must submit information including a valid email address. CubeMe! Media uses this information to screen out users who leave comments prohibited by our terms and conditions of use and to pick out topics of interest to discussion board users. CubeMe! Media will not pass this information to any other organization except in aggregate form.
The discussion board service may use cookies. A cookie is a piece of data stored on the user’s computer tied to information about the user. We may use both session ID cookies and persistent cookies. For the session ID cookie, once users close the browser, the cookie simply terminates. A persistent cookie is a small text file stored on the user’s hard drive for an extended period of time. Persistent cookies can be removed by following Internet browser help file directions.
By setting a cookie on a CubeMe! Media Site, users will not have to log in a password more than once, thereby saving time while on the site’s discussion board. We store a cookie on each user’s machine that contains a username and encrypted password. You can configure your browser to accept all cookies, reject all cookies, or notify you when a cookie is set. If you reject all cookies, you will not be able to use CubeMe! Media products or services that require you to “sign in,” and you may not be able to take full advantage of all offerings. However, not all CubeMe! Media services require that you accept cookies.
Third Party Cookies Some of our business partners may use cookies on our site (for example, advertisers). However, CubeMe! Media has no access to or control over these cookies, once we have given permission for them to set cookies for advertising. This privacy statement covers the use of cookies by CubeMe! Media only and does not cover the use of cookies by any advertisers.
Third Party Advertising The ads appearing on this Web site are delivered to users by Google, among other services. Information about users’ visit to this site, such as number of times they have viewed an ad (but not username, date of birth, or any other personal information), is used to serve ads to users on this site.
Log Files Like most standard Web site servers we use log files. This includes Internet protocol (IP) addresses, browser type, Internet service provider (ISP), referring/exit pages, platform type, date/time stamp, and number of clicks to analyze trends, administer the site, track user’s movement in the aggregate, and gather broad demographic information for aggregate use. IP addresses, etc. are not linked to personally identifiable information. We may use a tracking utility that uses log files to analyze user movement.
Legal Disclaimer Though we make every effort to preserve user privacy, CubeMe! Media may need to disclose personal information when required by law wherein we have a goodfaith belief that such action is necessary to comply with a current judicial proceeding, a court order or legal process served on any of the CubeMe! Media Sites.
Business Transitions In the event CubeMe! Media goes through a business transition, such as a merger, acquisition by another company, or sale of a portion of its assets, users’ personal information will, in most instances, be part of the assets transferred.
Links The CubeMe! Media Sites contain links to other sites. Please be aware that CubeMe! Media is not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every Web site that collects personally identifiable information. This privacy
About Advertising Calendar of Events Contact CubeMe with Tips Links Privacy Policy
Design Kitchen lamp Exhibition photography Photo Interior Travel Prefab Fashion Music
Gizmo Project Residence Technology Sculpture Hotel
Mobility Chair Table Video Lighting house Green
Seating Gadgets Latest Art Furniture
Architecture
RESERVE A BLOGAD
Privacy Policy « CubeMe
A privacy policy is a document that explains how an orga- nization handles any customer, client or employee infor- mation gathered in its operations.[23] It usually declares what specific information is collected and whether it is kept confidential or shared with or sold to other firms, researchers or sellers.[24] The policy should also explain if data may be left on a user’s computer, such as cook- ies. According to best practices, the policy should dis- close if data may be shared with or sold to third parties and if so, what the purpose is.[25] Personal information can be anything that can be used to identify an individ- ual, not limited to but including name, address, date of birth, marital status, contact information, ID issue and expiry date, financial records, credit information, medi- cal history, where one travels, and intentions to acquire goods and services. Most websites make their privacy policies available to site visitors.[26] For example, Face- book has updated its privacy policy to make it easier for users to understand, cutting around 70 percent of the previous privacy policy.[27] Critics also question if con- sumers even read privacy policies or can understand what they read. . A 2001 study by the Privacy Leadership Ini- tiative claimed only 3% of consumers read privacy poli- cies carefully, and 64% briefly glanced at, or never read, privacy policies.[28]
Spam
Spam
Spam, officially known as Unsolicited Commercial Email (UCE) or Unsolicited Bulk Email (UBE), is the use of electronic messaging systems to send unsolicited bulk messages.[29] Spam can be sent to personal email ad- dresses as well as to cell phones sent as a text message. Some frequently seen spam examples include advertising for specifically health-related products, pornography, and business opportunities, such as buying and selling stock. With a world full of technology and information around us, individuals can easily receive any email address from a number of ways. Companies receive email addresses either directly from the individual, or through 3rd par- ties that have a partnership with the other. Personal in- formation can be entered into a database and then spam can be sent out to those individuals. Spam can also be sent over social media sites like Facebook, Twitter, or Google+. Many email clients now have a separate folder marked “spam.” This is helpful to individuals because they will now be able to see what is considered “spam” before they open the email or attachment. With text mes- sages, most people ignore or delete those messages. Mar- keting databases are easy ways to get on a spam distribu- tion list.[30] Surprisingly, most spam is considered illegal, however there are certain guidelines that hackers can fol- low to be able to send spam emails or messages. It is difficult to stop the spamming, but in recent years, many have been convicted of spamming materials being sent to customers and individuals.
Protecting Against Spam
One way of safeguarding against spam is to protect the privacy of personal information. Individuals should pro- tect your e-mail address and other personal information.
7.1. COMPUTER SECURITY 205
Get rid of unwanted emails
Individuals can also surf the Web anonymously, opt out of some marketing activities, and use filters to limit your exposure to spam e-mails. One suggestion to avoid spam is to have two e-mail addresses. You should have one e- mail for personal address for family, friends, colleagues, and other trusted resources. The second e-mail should be a disposable or throw-away e-mail address which can be used for online shopping and signing up for free offers. One valuable piece of information is that less-legitimate sources of spam have unsubscribe links that do not work or that are present only to verify that your e-mail address is genuine! One online article suggests using the black- list option in your e-mail. Blacklists permanently block emails form selected senders or servers. Once you black- list a domain, server, or sender, those senders simply can- not contact you. The article also suggests to report spam to your e-mail provider, this will help over all to address the spam problem because the more you report spam the more your e-mail provider can work behind the scene to filter and block the sender, domain, or server from send- ing e-mails to you and other legitimate, personal e-mail addresses. Also, always be cautious of revealing personal information online. Lastly, make sure to use filters and opt out, which refers to following a predesigned proce- dure to remove yourself from marketing lists, or other- wise preventing your personal information from being obtained by or shared with others. When you opt out, you are instructing companies you do business with not to share your information with third parties.[31]
Properly Dispose of Hardware Containing Data
A perfect way to unintentionally, yet practically hand your sensitive information to computer thieves would be carelessly throwing away your hardware containing that information, thinking it is no longer worth anything.
Wipe, not just delete!
When throwing away an old computer, hard disk, or any other defective storage medium, it is more than crucial to make sure there is absolutely nothing left in that computer or storage medium. The simple “delete” button will not erase the data permanently. Instead, it merely deletes the pointer between the directory entry and the file so that new space is created for storage of new files. While old physical documents such as papers, CDs, and DVDs that are no longer needed should be shredded, the hard drives of computers should be disposed of by wiping the data using special disk-wiping software. While the data on a hard drive that is merely deleted can still be reformat- ted, and therefore recovered, completely wiping that data makes it very difficult, and even impossible for that data to be recovered. Two other ways to disposing old data is overwriting and degaussing. Overwriting data also makes it very difficult for the overwritten information to be recovered. Addi- tionally, old data can be degaussed by exposing the data to a very strong magnetic field so that the data is magnet- ically erased from the magnetic media. This concept of wiping any signs of data in an old medium is so important that even all businesses have to develop and implement a media sanitization or data destruction policy, for always destroying data that is no longer needed. [32]
7.1.5 Electronic Surveillance
Computer Monitoring Software
One popular tool of electronic surveillance is computer monitoring software. This software is used specifically for the purpose of recording keystrokes, logging the pro- grams or Web sites accessed, or otherwise monitoring someone’s computer activity. Some of the highest rated computer monitoring software includes SpyAgent and
206 CHAPTER 7. COMPUTERS AND SOCIETY
Do you get the feeling you're being watched?
WebWatcher.[33] It is legal to use this software, either on your own computer or the computers of your employees. However, installing it on another computer without the owner’s knowledge is typically illegal. Considering that this software is created to pretty much make sure your kids, spouse, or employees aren't doing anything on the computer that you don't want them to be doing, there are some ethical issues to consider. On the one hand, some- times kids need help building self-control and avoiding predators so having their internet time monitored can be helpful for parents to use as a teaching tool. On the other hand, if you are supposedly in a loving and trusting ro- mantic relationship, one could argue that you shouldn't be spying on them to be sure that they aren't cheating. As humans, we enjoy being trusted to do the right thing... and we get less credit for doing what we're supposed to do if put into an environment where there is no oppor- tunity to get away with something dishonest. Still, com- puter monitoring software continues to be popular, and that isn't likely to end in a global culture that grows in- creasingly paranoid.
Employee Monitoring
A typical surveillance system monitoring work production
Employees need to be very aware of their actions while working on the clock. Now, more than ever before, companies can monitor exactly what their employees
are doing or saying and how productive and efficient they are being while on the clock. Phone calls can be screened, emails can all be archived, website browsing can be tracked, and their every movement can be watched through cameras. Some practices are more common in different workplaces. For example, retail stores gen- erally keep their employees under close surveillance to make sure they are not allowing for theft, or partaking in it themselves. Other office positions can remote to the desktop of its employees and see exactly what is open on their screen. Some more extreme cases include GPS based systems that are installed in company cars, for ex- ample, to make sure the vehicle is within the designated areas. Some individuals see this as a breach of their pri- vacy, but employers are more concerned with the pro- ductivity, safety, and liability of their employees. An al- ternative to the continuous monitoring would be frequent training and education. Employers worry about the new avenues for individuals to misbehave at work due to the advances in technology.[34]
Video Surveillance
Video surveillance
Essentially, the idea of video surveillance is exactly what it sounds like: the use of video cameras to survey an area of monitor what is going on. We see examples of this ev- ery day: traffic cameras, police car cameras, ATMs, most retail stores, and even many mobile phones. The world of technology expanding so much that it is becoming in- creasingly difficult to find places that are not under some sort of surveillance. Many offices and schools implement these systems to keep track of students/employees and en- sure they have a visual record of an incident if anything were to happen. Police use this in their cars to obtain
7.1. COMPUTER SECURITY 207
Video surveillance sign
a record of their activities on the job. Retail stores and ATMs use them to reduce crime/theft. Most of us have, at one point or another, waved at those small black and white television screens that show us “on TV” in stores, when the truth is we were waving at the video camera recording our every action for someone to review later on. And, more shockingly, the photos and videos peo- ple take today just using their phones can be used to link persons to crimes, events, locations, and so much more. while the expansion of video surveillance does cre- ate some privacy concerns, it has been useful (especially combined with other technology like facial recognition) in solving crimes like discovering the people responsible for the Boston bombing, as well as many other crimes.[35] There are multiple problems with video surveillance other than privacy concerns. First off, politicians are trying to push for more video surveillance cameras to curb violent activities like terrorist attacks or murders. The only prob- lem is that video surveillance will not stop these actions, even though it might help find the culprit. The person committing the action is not deterred by the fact of them being on camera, and in some cases the individual ac- tually wants to be filmed to become infamous on news coverage of their actions. Another issue is the abuse of the video surveillance cameras. Reviewers of video cam- eras, mostly government officials, can blackmail people they are observing. An instance of this was when an of- ficial reviewed tape near a gay club and searched license plates to find the backgrounds of the men in the club to see if they were married in order to extort money. Other situations where this can happen are to prevent activists from meeting for racial, ethnic, or religious causes. A third issue is the fact that there aren’t many limits or con- trols on surveillance systems, and soon enough our every move will be watched by our government. This does lead to a privacy concern, but it should be noted. Many peo- ple like their privacy and video surveillance cameras are
slowly chipping away at this right of the people. In to- tal, there are many advantages and disadvantages to video surveillance.[36]
The military using electronic surveillance
As technology evolved so did the advancements in video surveillance. One of these many advances is All-Weather Radio Frequency Surveillance. This security system makes use of radio frequency detection to detect things even under heavy weather conditions such as fog. This is used by the military in detecting intruders. Another in- novation is something called SafeZone, which is a tech- nology that can spot the presence of weapons by detecting the shape of firearms. The technology also triggers things such as calling law enforcemnt or locking doors. Maybe one of the most useful innnovations is that of High Def- inition Video. Thanks to high definition video it has be- come easier for video surveillance to detect threats and compare faces to the criminal database. One innovation that is helpful for retailers is that of surveillance feeds on smartphones. By being able to put the surveillance feeds of cameras on smartphones it makes it easier for retail- ers to check their stores even while on the go. There’s also the fact that surveillance is now offered as a ser- vice. This makes having video surveillance more acces- sible even for those who don't know how to use video surveillance. Even though video surveillance is some- thing that some people don't accept, hopefully technology can still further improve video surveillance in order to at least try and make the world a little safer.[37]
Employee Monitoring
Employee monitoring refers to companies recording or observing the actions of employees while on the job. Common employee monitoring activities include screen- ing telephone calls, reviewing e-mail, and tracking com- puter and internet usage. Usually, the primary motive is to monitor internet usage for legal liability, but monitor- ing employee productivity can be another reason. Em- ployee monitoring may sound unethical to the point of it being illegal; however, legally, employees have little re- course, and the few cases brought up to court tend to go against the employee.[38] An increasingly popular way of
208 CHAPTER 7. COMPUTERS AND SOCIETY
Always watching
tracking employees comes in the form of smart of RFID- enabled ID cards. These cards are often used for ac- cess control (entering a building; automatically locking a computer when a certain distance is reached), but track- ing an employee using GPS is also possible. Compre- hensive employee monitoring systems can be expensive, so alternatives such as employee training and education are explored. Regardless of the techniques used, busi- nesses should inform employees about their monitoring practices, even though they are not required to by U.S. law. However, legislation is starting to address employee monitoring. For example, several states are considering to prevent employers from implanting employees with RFID chips without the employee’s consent. As of cur- rent, there are no strict laws in the U.S. surrounding em- ployee monitoring as the benefits of security, productivity measurement, and legal compliance outweigh the poten- tial negatives.
Presence Technology
Presence technology is the ability of one device con- nected to a network to recognize and identify another de- vice on the same network. This gives the ability for one device to tell the other device’s status, such as if it is being used or available for communication. There are many dif- ferent ways to implement this technology, including soft- ware, GPS, or RFID. A good example of this technology can be seen in Instant Messaging programs. A user is able to see whether or not other people are online and active on the messenger. Presence technology is an important part of the 3G wireless network.[39] Mobile phones use this technology all the time, such as being able to share your location with someone through GPS or seeing if the other person is typing on iMessage. Not only is this tech- nology good for personal use but also for corporate use. Presence management can be used in many methods, for example to see if a certain employee is available to help
Instant Messengers use presence technology so users can see who is available to chat.
a customer at the moment. Most of the time the user can change settings in order to allow certain features of pres- ence technology to be activated or not in order to protect their privacy.
7.1.6 Software Piracy and Digital Coun- terfeiting
Digital Counterfeiting
100 USD watermark
7.1. COMPUTER SECURITY 209
Digital counterfeiting is using computers and other digi- tal equipment to make illegal copies of currency, checks, collectibles, and others. It is important to be able to pre- vent digital counterfeiting that way the value of the cur- rency (if that is what is being counterfeited) will not lose its value. The prevention of counterfeiting is a concern of everyone and should not be taken lightly. The Trea- sury Department makes a new design of the currency ev- ery 7 to 10 years in order to not have the money all stay the same. New features on the currency help to make it harder or even impossible to remake. Watermarks and security threads are a few ways that the Treasury uses to help make the digital counterfeiting not possible. Wa- termarks are recognizable images on papers that can be viewed through transmitting light. On the 5 dollar bill, a 5 was added to the right of the portrait, while previously it was a watermark of Abraham Lincoln. Another water- mark was added on the 5 dollar bill, it was a column of three smaller 5s and they are to the left of the portrait.[40] These small changes really do overall help with being able to prevent counterfeiting since they are harder to remake.
Software Piracy
Anti-Stop Online Piracy Act
The unauthorized (and therefore illegal) copying of a computer program is known as Software Piracy. It is a widespread problem that often proves difficult to harness because computers are quickly and easily able to create exact copies of a single program. It is estimated that 42% of all software installed on personal computers globally (about 20% of all software in the U.S. and at least 90% in five countries) is installed illegally, leading to an an- nual monetary loss of $59 billion worldwide to software vendors. The act of pirating software includes, but is not limited to -- making illegal copies of programs and dis- tributing them to others, businesses extending software to more devices than permitted in the end-user license
agreement, retailers installing unlicensed copies of soft- ware on purchased computers, and illegally duplicating software and its packaging which are then passed off as legitimate. Pirated software, CDs, and DVDs may be downloaded from Web sites and peer-to-peer file sharing services, sold at online auctions, or disseminated other ways (regardless of profit), all of which are illegal. The SOPA has aimed to stop the illegality of pirating online materials, but it still remains illegal in the United States and most other countries. [41]
7.1.7 Computer Security and Privacy Leg- islation
Computer Security
Security Block
Computer security is the protection of computing sys- tems and data that can be stored or accessed. Being educated about the computers security will benefit the user by enabling people to carry out their jobs, educa- tion, and research supporting critical business process, as well as, protecting personal and sensitive information. Good security standards found that 10% of the security safeguards are technical and the other 90% security safe- guards rely on the computer user to adhere to good com- puting practices. When using a computer, it benefits the user by understanding how to keep their computer and data secure. Some key steps are to use secured passwords, making sure it’s personal that no one will discover and that you always will remember it, in addition to, making sure the computer is protected, not clicking on unknown links, and not downloading unknown files or programs onto the computer. To help reduce the risk, look out for padlocks that appear in the URL bar before entering any personal information. This leads to the risks of the security of per- sonal information, loss of business information or loss of employee and public trust. Other risks can be known for expensive reporting requirements in case of securing per- sonal, financial or health information.[42]
210 CHAPTER 7. COMPUTERS AND SOCIETY
The U.S. Safe Web Act of 2006
The U.S. Safe Web Act was brought about in December 2006; the purpose of which was claimed to protect con- sumers from Internet fraud. With the growing popularity and growth of the Internet, this has become an increas- ingly dangerous threat. The Internet is consumed with fraudulent users, spyware, and telemarketing, and this law sought to put an end to some of this fraud. It gave the Fed- eral Trade Commission (FTC) a decent deal more author- ity than they had previously had before it was passed, in hopes of protecting the consumers that use the Internet on a daily basis. There are a few things that the law changed that had not previously been allowed. First, it allowed the FTC to share information with foreign law enforcements and also aid them in investigations. In addition, it allows them to gain information from public law enforcement of- ficials that they would not have previously been allowed to receive lawfully. This act also gave them more power and tools in consumer investigations. Finally, the act seems to strengthen the United States powers with other foreign countries, and allows them to share and work together in ways that previously would not have been allowed. In conclusion, it seems as though the whole purpose of the bill was to give the government more power, and to allow them to lawfully impose in more ways than before.[43]
Other Legislation Related to Privacy
Privacy is a contentious issue in current discussion
Related to the issues of computer privacy and personal privacy in general are the Do-Not-Call Implementation Act of 2003 and the CAN-SPAM Act of 2003. Both laws were created with the hopes of ensuring protection of privacy, yet whether or not these laws have accom- plished this remains in question. The Do-Not-Call Im- plementation Act was designed to work in unison with the National Do Not Call Registry, which began in 2003 as
well. This was developed to give individuals more con- trol over the telemarketing calls that reach their house- holds. The Do-Not-Call Implementation Act relates to the National Do Not Call Registry specifically in that it allowed for the enforcement of the registry by allowing for the Federal Trade Commision to collect fees for its maintenance.[44] U.S. Consumers can register by phone or online, and phone numbers now remain on the registry permanently because of the Do-Not-Call Improvement Act of 2007. The CAN-SPAM Act of 2003 was designed to address the issue of unsolicited email messages (e.g. spam). Ac- cording to the Bureau of Consumer Protection, the law covers all commercial messages, and it applies to not just business-to-customer messages but business-to-business messages as well.[45] The maximum penalty is $16,000 per violation, yet the effectiveness of this act remains in question because it remains largely unenforced. Critics assert that the law creates problems for state laws that would have “provided victims with practical means of redress.”[46]
7.1.8 Review
7.1.9 Key Terms
Hardware theft The theft of computer hardware [47]
System failure The complete malfunction of a com- puter system
Freeware Copyrighted software that may be used free of charge [48]
Full disk encryption (FDE) A technology that en- crypts everything stored on a storage medium automatically, without any user interaction.[49]
Self-encrypting hard drive A hard drive that uses full disk encryption (FDE) [50]
Ruggedized device A device (such as a portable com- puter or mobile phone) that is designed to with- stand much more physical abuse than its conven- tional counterpart [51]
Surge suppressor A device that protects a computer system from damage due to electrical fluctuations [52]
Uninterruptible power supply (UPS) A device con- taining a built-in battery that provides continuous power to a computer and other connected compo- nents when the electricity goes out [53]
7.1. COMPUTER SECURITY 211
Disaster recovery plan A written plan that describes the steps a company will take following the occur- rence of a disaster [54]
Software piracy The unauthorized copying of a com- puter program
Digital counterfeiting The use of computers or other types of digital equipment to make illegal copies of currency, checks, collectibles, and other items.[55]
Marketing database A collection of data about people that is stored in a large database and used for mar- keting purposes
Opt out To request that you be removed from marketing activities or that your information not be shared with other companies [56]
Presence technology Technology that enables one computing device (such as a computer or mobile phone) to locate and identify the current status of another device on the same network [57]
7.1.10 Review Questions
1. Observing or reviewing employees’ actions while they are on the job is _____. 2. _____ _____ Software can be used to record an indi- vidual’s computer usage, such as capturing images of the screen, recording the actual keystrokes used, or creating a summary of Web sites and programs accessed. 3. ______ _____ is the use of video cameras to monitor activities of individuals, such as employees or individuals in public locations, for work-related or crime-prevention purposes. 4. True or False. Electronic profiling is the act of using electronic means to collect a variety of in-depth informa- tion about an individual, such as name, address, income, and buying habits. 5. Unsolicited, bulk e-mail sent over the Internet is ____. 6. A device that protects a computer system from damage due to electrical fluctuations is ____. 7. True or False. Encryption can be used for privacy purposes, in addition to security purposes. 8. Color copying money is an example of ____. 9. True or False. Very few major U.S. companies moni- tor the online activities of their employees. 10. The rights of individuals and companies to control how information about them is collected and used. Answers 1. Employee Monitoring 2. Computer Monitoring 3. Video Surveillance 4. True 5. spam 6. Surge suppres- sor 7. True 8. Filter 9. False 10. Information privacy
[1] http://www.consumerreports.org/cro/news/2013/06/ with-1-6-million-smart-phones-stolen-last-year-efforts-under-way-to-stem-the-losses/ index.htm
[2] http://www.android.com/
[3] http://www.allgov.com/usa/ca/news/top-stories/ state-sues-sap-over-failed-payroll-system-in-yet-another-tech-failure-131122? news=851725
[4] http://adeona.cs.washington.edu/
[5] http://www.webopedia.com/TERM/S/surge_protector. html
[6] Security anchor/tether assemblage for portable articles: U.S. Patent 6,081,9746,317,936 and 6,360,405 (Cor- nelius McDaid, John Ristuccia, Kryptonite Corporation - priority date: 1999-06-21)
[7] http://www.webopedia.com/TERM/M/mobile_device_ management.html
[8] http://www.air-watch.com/solutions/ mobile-device-management
[9] http://www.maas360.com/products/ mobile-device-management/
[10] https://www.apple.com/ipad/business/it/management. html
[11] http://en.wikipedia.org/wiki/Mobile_device_ management
[12] Understanding Computers 14th Ed. by Deborah Morley & Charles Parker
[13] http://www.panasonic.com/business/toughbook/ fully-rugged-laptop-toughbook-31.asp
[14] http://www.att.com/cellphones/samsung/ galaxy-s-5-active.html#fbid=pGXpDqukON3
[15] http://www.pivotcase.com
[16] http://www.computerweekly.com/feature/ Self-encrypting-drives-SED-the-best-kept-secret-in-hard-drive-encryption-security
[17] http://www.webopedia.com/TERM/S/software_piracy. html
[18] http://www.safenet-inc.com/software-monetization/ software-protection/
[19] http://www.marketing-schools.org/types-of-marketing/ database-marketing.html
[20] http://www.geek.com/mobile/ automated-electronic-profiling-the-art-and-science-550246/
[21] http://www.ecommercetimes.com/story/73966.html
[22] https://epic.org/privacy/profiling/
[23] http://whatis.techtarget.com/definition/privacy-policy
[24] http://www.businessdictionary.com/definition/ privacy-policy.html
[25] http://whatis.techtarget.com/definition/privacy-policy
212 CHAPTER 7. COMPUTERS AND SOCIETY
[26] https://en.wikipedia.org/wiki/Privacy_policy
[27] http://www.techtimes.com/articles/20324/20141117/ facebook-updates-privacy-policy-releases-basics-help-protect. htm
[28] https://en.wikipedia.org/wiki/Privacy_policy
[29] http://en.wikipedia.org/wiki/Spam_(electronic)
[30] http://en.wikipedia.org/wiki/Database_marketing
[31] https://www.americanexpress.com/us/small-business/ openforum/articles/7-ways-to-get-rid-of-spam-forever/
[32] http://www.infosec.gov.hk/english/computer/disposal. html
[33] http://monitoring-software-review.toptenreviews.com/
[34] http://www.huizenga.nova.edu/Jame/articles/ employee-monitoring.cfm
[35] http://www.cnn.com/2013/04/26/tech/innovation/ security-cameras-boston-bombings/
[36] https://www.aclu.org/technology-and-liberty/ whats-wrong-public-video-surveillance
[37] http://www.cio.com/article/2375438/physical-security/ 5-innovations-that-make-video-surveillance-more-effective. html
[38] http://www.scu.edu/ethics/publications/iie/v9n2/ brother.html
[39] http://searchunifiedcommunications.techtarget.com/ definition/presence-technology
[40] http://www.newmoney.gov/currency/5.htm
[41] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013950
[42] http://it.ucmerced.edu/security/ information-security-awareness-training/ what-computer-security
[43] http://www.ftc.gov/reports/ us-safe-web-act-first-three-years-federal-trade-commission-report-congress
[44] https://www.govtrack.us/congress/bills/108/hr395
[45] http://www.business.ftc.gov/documents/ bus61-can-spam-act-compliance-guide-business
[46] https://en.wikipedia.org/wiki/CAN-SPAM_Act_of_ 2003
[47] http://wiki.answers.com/Q/What_is_hardware_theft_ and_vandalism
[48] https://en.wikipedia.org/wiki/Freeware
[49] http://en.wikipedia.org/wiki/Disk_encryption
[50] http://www.computerweekly.com/feature/ Self-encrypting-drives-Whats-holding-back-SED-hard-drive-encryption-security
[51] http://en.wikipedia.org/wiki/Rugged_computer
[52] http://www.thefreedictionary.com/surge+suppressor
[53] http://en.wikipedia.org/wiki/Uninterruptible_power_ supply
[54] http://en.wikipedia.org/wiki/Disaster_recovery_plan
[55] http://en.wikibooks.org/wiki/The_Computer_ Revolution/Digital_Counterfeiting
[56] http://en.wikipedia.org/wiki/Opt-out
[57] http://en.wikipedia.org/wiki/Telepresence
7.2 Ethics
7.2.1 Intellectual Property Rights
FAQ Trademark License FAQ
Intellectual property rights are the legal rights which cre- ators are entitled to. Creators are the people who pro- duced intellectual property which are creative works that they have originally made. With these rights, creators can choose what can legally be done to the work and other rules that need to be followed. There are a vari- ety of original works that can have property rights. Some of these include: written work, drawings, graphics, and many more. Having rights is very important because respect should be given to someone who has original thoughts and can put those thoughts into creative work. There is a company called WIPO which are a self-funding agency that has copyrights, patents, trademarks, indus- trial designs, and also geographical indications used in e- commerce. This system is around because they recognize that creative works need to be protected by law and that they are around to support a creative environment. This company even has a magazine which displays the work that they have protected and boosts the work of creators worldwide. They also run workshops and have different forms of training to help innovators improve their skills and become familiar with new developments. The ability to have an agency support you and your work is a great step in the world of creativity, and keeping those intellec- tual property rights is what will continue to help creators flourish.[1]
7.2. ETHICS 213
Copyright
Copyrights are there to protect individuals’ work, such as literature, art and music. Enacted in 1976, Copyrights give the original creator rights over what they created. Even if you die, you still retain rights 70 years after your death. So let’s say you buy a CD from Zomboy,[2] that does not give you the right to do whatever you want with his music. Even though it is now your property, the artist still holds rights over the songs. Often times with trying to prevent piracy, many things will have digital watermarks, a slight change to content that most cannot see but iden- tifies copyright holder.
Trademark Symbols
Trademarks are words, phrases, symbols, designs, or a combination of these that are used as an identifier in or- der to help consumers identify and distinguish one prod- uct/service from another one which might be similar. This is also referred to as their “logo”. Trademarks are
usually registered with the U.S. Patent and Trademark Office (USPO)and use the letter R enveloped in a cir- cle next to the logo to signify this. Trademarks which are claimed but unregistered are allowed to use the print tm alongside they're logo to represent that a claim has been made so as to deter others from using it. The purpose of a trademark is to protect the logo from being used by competitors who may want to “knock off” a more rep- utable company, though trademarks also protect domain names as well. Many companies want to set up a website using a domain name which matches their product so a consumer can instinctively find they're web address, and a trademark will often safeguard against another company using it.[3]
Patents are similar to Copyrights and Trademarks but protect a person’s invention rather than their literary ac- complishments or company logos. Patents are usually granted for a 20 year period and legally authorize the sole rights of an individual to manufacture or produce that which s/he invented. Often it is a unique product but it can also be a unique process such as the Born-Haber Cycle.
7.2.2 Ethics
do YOU have computer ethics?
The general definition of the word “ethics” defines the elements important to humans’ morals. Ethics could be referred to as specific values, standards, rules, and agree- ments. For example, not being involved in software piracy is a matter of ethics. Computer ethics is a set of morals that regulate the use of computers. It is impor- tant for computer users to be aware of the ethical use of copyrighted material, the ethical use of resources and in- formation, and ethical use of school, company, and em- ployee information.[4] Common issues of computer ethics are the following: privacy concerns, how computer af-
214 CHAPTER 7. COMPUTERS AND SOCIETY
fects society, and intellectual property rights. It is a very common and easy practice to burn a CD or movie for a friend. However, another option would be to tell the friend to buy the CD or movie as an ethical alternative. The privacy of another person is also an ethical issue of today. People’s information is easily accessible through the computer; the ethical solution would be to not access another person’s private information unless given permis- sion. Ethics certainly guide our behavior, and it is the source of the acts we will and will not part take in.[5]
Young people use cell phones so often that they might not even realize that using them on a test is cheating.
One ethical issue introduced by the increased prevalence of new technology is the rise in cheating among students using technology. As students have more technology, they naturally have more ways to cheat—ways that adult teachers who don't use all the new technology might not be aware of. 35% of students in one study admitted to cheating by using a phone. This can be done by storing notes on a phone and looking at it in class, texting some- one outside of the class for an answer, and so on. A shock- ingly large number of teenagers seem to not even 'realize' that this is cheating; around or over 20% didn't think that it was. They're so used to having their cell phones at- tached to themselves as a part of their body that they don't realize that it actually isn't something they're supposed to be using at all times, and they saw no difference between screaming an answer across a class room and covertly tex- ting it to a friend.[6] Young people need to be aware that cheating is cheating even with technology so they don't get in trouble for academic dishonesty, and faculty need
to be aware of how students might be cheating using their phones, iPads, etc. to prevent it in the classroom.
7.2.3 History of Computer Ethics
1980’s Employee
Computer ethics is a concept that is growing larger ev- ery day with new advanced technology. Computer ethics first came about in the 1970’s as computers were becom- ing integrated into homes. Computers today are used at home, in schools, and in powerful companies. This field has taken ethics to a whole new level, especially due to privacy issues found throughout various businesses. This form of ethics is also now offered to study at many uni- versities around the world. Computer ethics includes the various philosophical aspects of ethics, as well as psycho- logical and sociological interpretations. When the field was first discovered in the 1970’s, applied ethics was used to describe the new concept. Applied ethics consisted of a combination of utilitarianism, as well as Kant ethics. At the time there was much controversy to what comput- ers would bring to society. Some thought that computers would create more ethical issues, whereas others thought it put a so-called “twist” on old ethics. In the 1980’s the computer was thought to be the closest object to a univer- sal tool available to individuals. In essence, the integra- tion of the computer into every day society was not easy. The generation of the computer was new, as well as excit- ing. But nobody had used it before, including businesses and individuals. There would have to be some form of ethical guidelines to using these new products that nobody had much experience with. Nowadays, computer ethics covers a wide variety of topics such as: computers in the workplace, computer crime, professional responsibility, and privacy and anonymity. [7]
7.2. ETHICS 215
Napster Logo
Ethical Use of Music
The sharing of music over the internet has continuously been a problem over the past few years and it is still a major problem today. The music controversy began with Napster, a peer-to-peer file sharing web application that was created to allow users to share music files via the in- ternet. Napster originally started as a small web applica- tion for a few friends to share music on, but as the ap- plication grew in users, it began to strike the attention of the music industry. Some artists, specifically Metal- lica and Dr. Dre who filed a law suit against Napster, were outraged at the web application and in 2001, Nap- ster finally closed due to the losing of a lawsuit against the Recording Industry Association of America. Napster and other peer-to-peer sharing websites that still exist to- day, such as The Pirate Bay, Mediafire, and Megaupload, are a large controversy because the copying of songs for non-commercial use is legal under the fair use concept,[8] however, downloading files from a peer-to-peer website without compensating the artist is a violation of copyright law under Digital Millennium Copyright Act There are several websites that can be used to convert YouTube videos to a MP3 format you can down load to your computer. The most well known of these pro- grams is called ClipConverter, but there are other pro- grams. ClipConverter is a free online-based service con- verts and online video to a MP4 or MP3, and then these files can be downloaded to your computer. There have been similar programs in the past, but these have been deactivated due to pressure from Google, the owner of YouTube[9]. ClipConverter converter continues to oper- ate because of the guidelines and rules placed on users. Users are allowed to download the videos for fair use, meaning personal, non-commercial use. Personal use of a video is legal, but if a user sells the video for profit, or passes it off as his/her own, that is a copyright violation,
and illegal. As a condition of using the ClipConverter service, the user agrees to only use the video for personal use, and agrees to not involve ClipConverter in any type of copyright lawsuit brought against the user. It is because of this policy and other strict user rules and policies that allow ClipConverter to operate in a legal way.
New youtube logo
To combat the infringement of copyright law due to il- legal file sharing, the music industry began placing Dig- ital Rights Management (DRM) control on downloaded files so that they couldn’t be shared. However, this also stopped users from being able to transfer the files to other personal devices. Today, many music downloading ser- vices, such as Apple’s iTunes, have switched to MP3 or MP4 formats to allow users to view files on multiple per- sonal devices.
Film Piracy
The illegal copying and distribution of movies and TV shows is called film piracy. The rate of which people commit film piracy has been growing exponentially since 2004. This is most likely due to the fact that online peer- to-peer file sharing has become a lot easier.[10] According to the Motion Picture Association of America (MPAA), film piracy causes an estimated loss of $18 billion dollars per year worldwide. This statistic is estimated because the MPAA has to determine how many people would have actually watched the film if it weren’t for free, or at a discounted price. Ever since 2004, authorities have been pushing to reduce film piracy. In 2005 the Family Enter- tainment and Copyright Act was put into place. This act makes recording a movie in a theatre illegal in the United States. Besides laws, there have also been things like vi- sual FBI Anti-Piracy Warning Seal’s added to DVD’s. This seal is shown when the DVD is played, and be- fore the actual movie starts. However, this doesn’t al-
216 CHAPTER 7. COMPUTERS AND SOCIETY
FBI Anti-Piracy Warning Seal
ways effectively stop a pirate from stealing the movie.[11] There are many software programs used by authorities and private companies to prevent the illegal trade of pi- rated movies. This software is able to monitor websites that host peer-to-peer file trading. If a company’s film is being misused over the internet, the software is capable of sending infringement notices and collecting important data. All of this information could be used to build a court case against the violator.[12]
Computer Hoaxes and Digital Manipulation
Example of a photo that has been digitally manipulated (edited)
A computer hoax, or virus hoax, is an inaccurate statement or story spread through computers, typically through am email. Usually the email warns the user about a virus or worm and instructs the user to forward the mes- sage (which spreads the virus) or recommends that the re- ceivers download an infected file attachment. These virus hoaxes can often be distinguished by their lofty and en- ticing wording or by claims that sound formal and autho- rized. These types of emails use people’s fear of the in- ternet to manipulate their actions and thus spread a virus or computer hoax; many consider these fake emails to be worms in and of themselves because of this.[13]
Digital Manipulation is editing or altering any type of dig-
ital content. The most commonly thought of is photo- shop, which is editing an image so that it has little to no resemblance of the original image. This can be any- thing from adjusting the “exposure” or a photo or us- ing an airbrush tool, to combing two photos to make one or adding portions that were not in the original (such as a large moon covering half the sky behind the Chicago skyline).[14] But digital manipulation also includes alter- ing text, music, movies, or voice interviews. The main is- sue when it comes to ethics in digital manipulation is that copyrights cannot be violated and the original digital in- formation cannot be misused or misinterpreted. Also, in- tentions and purpose are key in deciding “how far is to far” when it comes to photo-shop or other editing methods.[15]
7.2.4 Computers and Your Health
Physical Health
There are some physical problems that can be caused by computer use such as eyestrain, blurred vision, fatigue, headaches, backaches, and wrist and finger pain. One kind of health problem that occurs is repetitive stress in- juries, which is when doing the same thing over and over causes hand, wrist, shoulder, or neck pain. Using the keyboard and the mouse can cause repetitive stress in- juries. One repetitive stress injury that is related to repet- itive finger movement is carpal tunnel syndrome, which is a painful condition of the hands and wrists.[16] An- other repetitive stress injury is related with typing on the smaller keyboards of mobile devices and this is called De- Quervain’s tendonitis. There can also be many eye prob- lems caused by looking at a computer screen for too long. Another concern is hearing loss because many portable media devices can be turned up too loud and cause hear- ing problems. There is also a concern with radiation that can be emitted from wireless devices. There are ways to avoid these physical health problems caused by comput- ers. One way is to make sure that you are comfortable while at the computer and that you use a good chair that will be supportive for your back and neck. It is also im- portant to just be aware of these possible physical health risks caused by computers because it is something that is often overlooked.[17]
As mentioned before, most people today interact with
7.2. ETHICS 217
Computer Workstation Variables cleanup
some type of computer daily. We have learned that there are many risk factors associated with the extended use of computers. Some of those risk factors include eye strain, fatigue and upper and lower body discomfort. Luckily, there is a solution to these problems. It is called er- gonomics. Ergonomics is a technology which focuses on making the workspace as functional, safe and comfort- able as possible. One thing computer users should con- sider when using the computer is wrist strain. It is impor- tant for the user to keep his wrists as straight as possible. Some causes for a bent wrist can be the keyboard being too low or high, or it being tilted upward. A solution to this can be to adjust the keyboard to the appropriate height or adjust the height of the chair. Another solution could be to use a split keyboard or what is known as an ergonomic keyboard. Another risk people face with ex- tended use of the computer is back discomfort or even back disorder. This can be caused by an inadequate chair that lacks support for the back. It can also be caused from lack of foot support or from slouching due to fatigue. Some solutions to these problems would be to use a lum- bar cushion or to utilize a foot rest. It is also important for a user to take frequent breaks and change positions often. Many people today are exposed to extended com- puter use whether it is for a job or for entertainment. It is important for computer users to know the risks associ- ated with over-usage and to be familiar with ergonomics in order to create the safest and most comfortable envi-
ronment for themselves.[18]
Computers in Medicine
Fitibit Flex
In the same way that computers can be hazardous to one’s long term health, they can also be used to monitor and, in-fact, encourage healthy habits. Sitting at a computer sedentary for hours on end day-in and day-out can lead to eyestrain, headaches, etc. as was previously discussed. However, in recent years, health and medicine have cap- italized on the use of computers to further their industry. In hospitals and labs, CAT scans, X-rays, EEGs, EKGs, heart monitors, blood pressure and blood sugar scanners, and much more have been used to assess and monitor an individual’s health. Certainly these additions to the medical field have made medicine a much more precise science and helped countless individuals who were suf- fering. However, computers have not only been used in reactive situations. They now can also help an individ- ual be proactive about their health with the introduction to embedded computers, monitors, and biometrics. One example of this is the three-dimensional accelerometer (better known by the brand name “Fitbit”). These tech- nologies allow the mechanism to gather data about the human body, interpret the data into usable information, and also store it in case a medical professional needs ac- cess to real-time health records. They can give an individ- ual information about heartbeat/heart rate, sleep patterns, amount of physical activity, etc. and, in some cases, can even recommend that a person change certain behavior to combat unhealthy habits. [19]
Stress of Ever-Changing Technology
Today we see a lot of kinds of changes that are causing a great deal of stress and anxiety. Most of these changes are directly related to the digital revolution and have only become problems in the last 10 to 20 years.[20] Some peo- ple can’t figure out how to connect the game station to the TV. The cell phone rings just as the person about to walk out the door. Modern technology has infiltrated the
218 CHAPTER 7. COMPUTERS AND SOCIETY
Relaxation
workplaces, people’s cars and their homes. According to the Angus Reid, 14% of Canadian workers identified new technology in the workplace as a significant source of stress. Never before have individuals been asked to adapt as rapidly. Instant communication and exponen- tially growing technology lead us to one of the few ab- solute truths – Technology change is constant. Technol- ogy has reconfigured the nature of work and our social relationships on the job.[21] People feel overwhelmed by the volume of emails and calls that they receive. Though people cannot stop this technology roller coaster, they can use a variety of practical strategies to develop resilience and renew and replenish themselves. Some of the sim- plest skills that the people can learn to be more resilient to stress are deep relaxation and self-care. It can convert fatigue into energy and restlessness into calmness.[22]
Emotional Health
Burnout
Because of our fast growth and use of technology there are many positive advantages of using computers and much more; however, in recent years emotional health has become an important factor with the use of comput- ers and technology. The use of computers in general can cause much stress and anxiety for workers in different
fields today. When computers were first introduced to the working field, secretaries had to learn how to change from a typewriter to a keyboard. Many people now widely un- derstand the use of computers, but the downfall is keeping up with the changing technology. Every few years a new system, computer design, etc. are updated and sent out to the market. This makes operating a company more diffi- cult when programs and systems need to be updated. Be- cause the Internet can be accessed 24/7 the stress of being “on-call” is worrisome to many workers. They worry they do not have enough down time to themselves, after they come home from work that day. In the U.S. information is right at citizens’ fingertips, which can sometimes cre- ate an information overload. There is always news to be caught up with, as well as catching up with email, text messages, and social media as well. Many can become exhausted from being on the computer (or cell phone) too much. This is called burnout which is long-term exhaus- tion and diminished interest in work. A more common type of “emotional health” deals with teenagers who have a technology addiction. Social media plays a huge role in this now today.
Avatar of virtual world
Internet Addiction The virtual world has much simi- lar with reality. His mysterious and unpredictable are like the uncertainty and volatility of the world. People can play their chosen online roles, similar to the masks, peo- ple put in everyday life. At the same time virtual world declares easy available advantages over the real world. You can achieve success through creativity, concealing defects. It gives individuals the opportunity to take any role which can be also easily be replaced by another one. And all this is given without any responsibility, without fear of the consequences of rejection or condemnation. The network person feels protected and inaccessible, can easily express their opinions, which could hardly express in real life. The virtual world gives the illusion of pro-
7.2. ETHICS 219
tection from loneliness. At the same time it provides an opportunity to get away from communicating with real people, whose opinion would have to be considered. Net- work allows you to simulate reality by creative a state of endless possibilities and the search of discovery. A surf- ing the Net gives the feeling of being in the “flow” and a full immersion into an effect disconnection from the external reality with a sense of being in another world, another time, another dimension. [23]
Internet addiction
Many people today are addicted to the internet. Addi- tionally many people do not know that they are addicted to the internet. There are many signs of internet addiction as well. For example if you ever feel like you are always thinking about the internet that would be a good sign. If a person is using the internet increasingly in order to re- ceive satisfaction, and if you are continually failing to cut back on using the internet, those are also signs of addic- tion. If you ever feel restless or depressed while not on the internet, or feel like you are on longer then intended to be, those add to come signs of internet addiction. If some or all of these signs describe a person then they are addicted to the internet. Some tips on breaking this in- ternet addiction on your own are to understand that you have a problem with the internet. Next is to build coping skills. Many people become addicted to the internet be- cause it is their outlet for stress and anger. Being able to change the way a person copes with their problems would be extremely beneficial. There is also therapy, counsel- ing and support groups to take advantage of and help with this addiction like any other.[24] It is important to be able to overcome an internet addiction to be able to fully ap- preciate life and not be concentrated on intangible items and ideas like the ones on the internet.
Cyberbullying
According to stopcyberbullying.org, cyberbullying occurs when a minor is tormented, threatened, harassed, humili- ated, embarrassed or otherwise targeted by another minor using the Internet. These acts can be committed through interactive and digital technologies, or mobile phones. To be considered a true cyberbullying incident, minors must
Stop Cyberbullying
be involved on both sides, or at least instigated by one in an attempt to harm, another. If and when adults be- come involved, it then becomes cyber-harassment or cy- berstalking, and is wholly different from cyberbullying. For most, it is usually not a one time event, unless it is a legitimate threat of serious harm. Children are typically aware of the extent of present danger or hurtful ideas, while parents may be more concerned about offensive language used.Ultimately, cyberbullying could lead to a misdemeanor charge, though if the child is young enough, it juvenile delinquency is an option. Often, it does not go that far, yet many parents try to pursue criminal charges. If hacking, password breach, or identity theft is involved, it can be a crime of state and federal law. [25]
7.2.5 Technology Access
The U.S. Digital Divide
Helping each other understand and use the Internet builds strong bridges for humanity
220 CHAPTER 7. COMPUTERS AND SOCIETY
Though the exact percentage is argued over by the ex- perts, we can be happy to know that in the United States the digital divide continues to shrink. About 80% of the population of the United States uses the Internet. They use the Internet at school, work, home, and everywhere else. It’s rare to find a Mcdonalds, one of the lowest com- mon denominator eating establishments, that doesn't have a Wi-Fi connection. Computers and Internet access are always getting cheaper, which is great news because stay- ing connected to the world is such an important quality. We stay alive and thrive through building relationships of all different kinds and the Internet is a powerful means of obtaining these relationships. Not only that, but most jobs today require the use of the Internet in one way or another. Due to the importance of the Internet however, ideally the statistic of users in the United States would be closer to 99%. According to Forbes, there are sev- eral reasons why some people have never used the Inter- net or don't use it very often. The biggest percentage of them said they don't want or need to go online, because they're either too busy or because they think the Internet is a waste of time. A slightly smaller number of them said it is difficult or frustrating to go online, either be- cause they don't understand or are physically unable.[26] Ultimately, the importance of the Internet is understood the world over, meaning that the digital divide in the U.S. will continue to shrink so our country can stay competi- tive with Europe and Asia especially.
Global Digital Divide
XO-Beta
The Global digital divide is an issue that our world seems to be facing more and more as time goes on. Like the US Digital divide, it is a comparison of groups of peo- ple with access to technology but on a global scale in- stead of a country scale. The problem arrises when one country’s people has more access to technology and /or communications than another country. Most developed countries have a majority of their population with some access to technology, however it seems that many devel-
oping countries lack the technological accessibility that the others have. The largest problem caused by this is the lack of education. The internet today is such a source of information that one could potentially gain their entire college degree while hardly ever stepping foot in a class- room. Many people around the world lack the opportu- nity to gain an education because of their lack of access to the internet and other technology that would help them to learn things at a faster, easier, or more efficient rate. The internet has so many uses: school courses, communica- tion, language tutoring, translations, calculations, and so many more.[27]
More on the Digital Divide
Global Digital Divide1
The concept that is called the digital divide is the reality that technology, specifically computers and the Internet, is not available to all individuals. The digital divide is thought to be based on physical access to computers, In- ternet, and related technology. Some people consider the people that have access to computers and the Internet but do not understand how to use it are also part of the cate- gory of people that do not have true access to digital tech- nology. One article explains that there are multiple di- mensions to the digital divide. It claims the difference in not necessarily determined by the access to the Internet, but by access to ICT (Information and Communications Technologies) and to Media that the different segments of society can use. Other factors that should be consid- ered are the quality of connection to the Internet and the cost of access to the Internet. Researchers also report that disadvantages can take such forms as lower-performance computers, lower-quality or high price connections, dif- ficulty of obtaining technical assistance, and lower ac- cess to subscription-based contents.[28] The reason that the digital gap is a concern for society is that information and communication technologies are vital to quality civic life. One article explains that access to new technology splits clearly along socio-economic class lines. Accord- ing to U.S. census data, more than 30 million homes have no broadband access, most of them concentrate in some
7.2. ETHICS 221
of the poorest parts of the country. According to an- other survey 84% of the teachers surveyed felt that today’s digital gap is leading to greater disparities between afflu- ent and disadvantaged schools.[29] Technology can inform people by creating mutual understanding about different cultures and societies; technology also plays a part in ed- ucation and governmental reform. By lessening the digi- tal gap economic equality, social mobility, and economic growth will be more readily available.
Assistive Technology
Toby Churchill shown with assistive technology
The Americans with Disabilities Act requires companies with more than 15 employees to make reasonable accom- modations for anyone that has known limitations. Nowa- days, there is hardware and software specifically designed to aid individuals with physical disabilities. The most common technology that has been introduced is used to help those who are visually impaired or hard of hearing. There are various input devices available today to assist users communicate, usually on the computer. Braille or large-print keyboards, one-handed keyboards, switches, eye tracking systems, pointing devices, and voice input devices are all used today. In addition to the various in- put devices, there are output systems as well. The most common one is a screen reader that can read text informa- tion for the blind. There are also printers that can print in Braille instead of the conventional ink. Assistive technol- ogy is not always the best option, however. Often times it can be too expensive for the individual and not match
their exact needs. [30] Devices should be researched and tried out before purchasing. Training for these devices also needs to be taken into consideration. For example, what if this technology stops working for the user?
Braille, the text language for the visually impaired.
So how do some of these assistive devices such as Braille keyboards, one-handed keyboards, eye tracking systems, pointing devices, and voice input devices work? First off, made up of raised dots that signify a “language,” and thus can be read by touch, Braille keyboards allow the visu- ally impaired population to type and enter any text for the computer in Braille. Secondly, to assist people with lim- ited movement of only one hand, each of the one-handed keyboard’s key contains two letters (accommodating both the left and right side keys on a conventional keyboard), making it easier for all keys to be reached with just one hand. They also provide with the ability to input data to the computer hands-free through speech recognition systems. To act as mouse alternatives, many other point- ing devices like foot-controlled mice (controlled solely by the feet), head pointing systems (directed using simple head movements), and eye tracking systems (tracking the movement of the eye) are commonly used. To add on to all these types of outstanding assistive technology, there is also another alternative input system known as “sip- and-puff” system, which is activated by one’s inhaling or exhaling! [31]
Next, once the data has been input into the computer us- ing any of these assistive input devices, assistive output devices come into play. These devices include screen readers, which read aloud all the text information on the screen; Braille displays act similar to Braille keyboards as they continuously convert screen output into Braille form. Lastly, there are also Braille printers—sometimes known as Braille embossers—which transfer and print computer generated text into embossed Braille output. Therefore, instead of the traditional ink, the embosser creates raised dots on a page for the visually impaired to read.[32]
222 CHAPTER 7. COMPUTERS AND SOCIETY
Assistive devices
Assistive Technology in the Classroom Assistive technology can be especially helpful in the education set- ting. Thanks in large part to the mainstreaming and inclu- sion efforts in schools today, students of every ability are integrated into traditional classrooms. This integration can be greatly aided by the use of assistive technology. [33] Assistive technology allows students with disabilities to learn and complete lessons more independently. Edu- cators can use a variety of tools to help all types of stu- dents. Screen readers can be used to read text to visu- ally impaired students. There are many programs avail- able (some are even free) that can be used to read doc- uments aloud to students. This can be helpful for both visually impaired students, as well as students that are cognitively impaired and unable to read. Close caption- ing and subtitling help students that are hearing impaired. Eye tracking systems as well as sip and puff systems are especially helpful for students with mobility impairments. Voice recognition software can also provide a way for stu- dents to write more efficiently without the use of a key- board. Adding these technological advancements to the classroom allows students to participate in lessons and ac- tivities that would not otherwise be available to them.
7.2.6 Environmental Issues
Green Computing
This refers to the use of computers in an environmen- tally friendly manner, but computing is not currently as environmental friendly. According to threener electron- ics only 2 out of 18 of the Pc are considered on the green rating. The reason is because companies are subjected to make energy and hence cost saving in the face of ris- ing electricity prices. One of the activates that could help environmental savings is existing hardware which can be in place of it there are software’s called LittleGreenGe- nie. This software permit certain individuals to measure reduce and carbon offset from computer use. Its stats that it takes about 1.8 tons of chemicals, fossil fuels and water to produce a typical desktop computer and there’s about one billion PCs sold. Although putting a computer
The color Green...
on standby or sleep mode will save a lot of power, peo- ple are unaware that shutting down a computer doesn't completely turn it off because the computer power sup- ply will remain physically switched on. This leads the motherboard still partially on waiting for a signal to boot up again. The following are certain tasks that can be ben- eficial in reducing energy consumption which are lower power hard drive, visualization, cloud computing, energy effecting coding, improved repair, re-use recycling and disposable and less pollutant manufacture.[34][35]
Solar Power
Instead of reducing energy consumption and electricity costs, another option is to use solar power. Solar power is the conversion of sunlight into electricity using photo- voltaic cells. These cells can be packaged into a frame, and a frame into an array, based on how much solar power is needed for the building or area. The process has slowly become cheaper due to our increase in technology and knowledge of solar power. As of right now, we are con- sidered to be in our third generation of solar power be- cause of our use of new materials like nanotubes, silicon wires, and solar inks. This is a step up from the first gen- eration, which used solely silicon as a material, and then the second generation, which used thin-film solar pan- els. As the capability of solar power becomes cheaper, more products are incorporating solar power as a power
7.2. ETHICS 223
Solar Panel
source. Examples of this are the solar powered phone charger and solar powered calculator. Solar powered cal- culators have been around for a while because calculators do not require much energy, so the solar panel is very small and therefore cheap. The solar powered charger has come out more recently because the newer flexible technology made it feasible to produce. Solar power has been a greener way to consume energy.[36]
Recycling of Computers and Other Electronics
Given the reliance of the commercial world on computer technology it is easy to overlook the inherent unsustain- ability of computer production. Computers have become embedded in contemporary culture and play a crucial role in the global economy, but as the industrialized world continues to degrade the environment one must become aware of the negative impacts of computer use and con- sequently work with possible ways to reduce them. The Chicago Recycling Coalition states that, on average, 240 kg of fossil fuels are consumed in the process of pro- ducing a desktop PC.[37] In a time when fossil fuel sup- plies are decreasing at an alarming rate it is important now more than ever to be conscious of consumer deci- sions. The issue of fossil fuels aside, computers con- tain arsenic and mercury while computer monitors can contain several pounds of lead. This is one reason why simply disposing computers into landfills is problematic. Instead, the Chicago Recycling Coalition advises con- sumers to donate computers to various organizations and charities, give older computers to family and friends who
Find a recycling center that accepts electronics
need them, and find locations that offer recycling ser- vices. The EPA provides a utility that helps consumers and manufacturers know where they can donate or recycle their electronics.[38] Mobile devices, PCs and TVs make up the “Electronic Devices” category, and after selecting a device one can choose a company to see what services are offered.
You should recycle computers. Don't throw them away.
Before recycling your computers you may want to do a few things. In order to protect your information and pri- vacy, you should wipe out your hard drive. However, just deleting files is not enough. Cyber criminals are very ca-
224 CHAPTER 7. COMPUTERS AND SOCIETY
pable people and they will find a way to find informa- tion on your hard drive that you “deleted” the informa- tion. There are programs on the internet that you can use to “sanitize” your hard drive. An even easier way is to just remove the hard drive altogether. Other ways to recycle your devices is to donate them. You could even help your community out by having a fundraiser to col- lect everyone’s technological garbage and then you can donate them. This not only helps the community but also the environment. Now if you’re not looking to get rid of your entire computer you do have a printer. You will al- ways come to the problem of running out of ink. Instead of throwing out these old cartridges, you could just have them refilled. Not only is this good for the environment, but it can also help you save money because refilling ink cartridges is worth a fraction of the cost of buying new ones.[39]
E-Waste
Huge amounts of e-waste is not disposed of properly.
E-trash, or e-waste, is a growing problem in modern soci- ety. The issue of dealing with the huge amounts of elec- tronics that are being outdated and thrown away asks the question; what do we do with all this junk? Although e-waste only makes up about 2% of America’s trash in landfills, it comprises 70% of the country’s toxic waste. A lot of this toxicity is because of the huge amounts of lead that can be found in electronics. Between 20 and 50 million metric tons of e-waste is disposed of every year, but only about 12.5% of e-waste is actually recycled prop- erly. It is important to recycle e-waste not just to protect the environment but also to harvest the high amounts of precious metals within the electronics. Just in cell phones alone, over $60 million in gold and silver is dumped ever year.[40] A lot of “e-waste” is actually not waste at all, and can be recycled and reused if dealt with properly. E-waste is unfortunately shipped to developing countries illegally, which is not a responsible or ethical way of managing the waste.[41] In order to ensure that your e-waste is properly recycled you should find a recycling center near you. You can use this website http://search.earth911.com to find a
local center and learn how to properly dispose of your electronic waste! [42]
Family Entertainment and Copyright Act of 2005
Movie Copyright Laws
There’s no question that copyright laws are pushed to the side when it comes to copying illegal things such as movies, music, and videos. People act as if there is noth- ing to risk, and it does not matter if you break the law. However, the Family Entertainment and Copyright Act, which was passed in 2005, made these offenses just a lit- tle bit more serious. The law worked to make three of- fenses more defined and punishable than they were be- fore. First, it made sure that no one was allowed to bring a camcorder into a movie and record it. This works to stop people from selling movies that they do not have le- gal copyrights to. Second, it worked to make sure that there was no illegal prerelease of movies that had not yet been released to the public. The act actually states that this offense is punishable by a large fine or even time in jail. Finally, it allowed certain technology to be in- stalled into DVD players that permits the user to auto- matically skip or mute entire portions of a DVD, allowing them to get passed crude, violent, or inappropriate parts that they would not have wanted to watch. Basically, the law just worked to reinforce previous copyright laws that seemed to be pushed aside without users giving them any consideration.[43]
Other Related Legislation
The Family Entertainment and Copyright Act of 2005 is just one example of the several laws surrounding in- tellectual property rights. The U.S. Anticybersquatting Consumer Protection Act of 1999 makes domain name cybersquatting illegal. This law was targeted at “cyber- squatters” who register internet domain names contain- ing trademarks with no intention of creating a legitimate website, but instead plan to sell the domain name to the
7.2. ETHICS 225
Don't break the law
trademark owner or a third party. For example, if a new trademarked company by the name of Shmauffle wanted to create a website called www.shmauffle.com, a person who bought the domain name, and is doing nothing with it, has to give it up to Schmauffle. Another major law is the Digital Millennium Copyright Act(DMCA), which makes it illegal to circumvent antipiracy measures built into digital media and devices. Other laws, such as ones to increase penalties for illegally sharing music via internet, are proposed on a regular basis. Legislation regarding ethics has proven to be much more difficult to pass. For example, laws surrounding the distribution of indecent or offensive material online can be declared unconstitu- tional based the right to free speech. As a result, very few ethically oriented laws have been passed in recent years.
7.2.7 Review
Terms and Definitions [44]
assistive technology Hardware and software specifically designed for use by individuals with physical disabilities. burnout A state of fatigue or frustration usually brought on by overwork. business ethics Standards of moral conduct that guide a business’s policies, decisions, and actions. carpal tunnel syndrome (CTS) A painful and crippling condition affecting the hands and wrist that can be caused by computer use. code of conduct A policy, often for a school or business, that specifies allowable use of resources, such as comput- ers and other equipment. code of ethics A policy, often for an organization or in- dustry, that specifies overall moral guidelines adopted by that organization or industry.
computer ethics Standards of moral conduct as they re- late to computer use. computer hoax An inaccurate statement or story spread through the use of computers. copyright The legal right to sell, publish, or distribute an original artistic or literary work; it is held by the creator of a work as soon as it exists in physical form. cybersquatting The act of registering a domain name with the intent to profit from the goodwill of a trademark belonging to someone else. DeQuervain’s tendonitis A condition in which the ten- dons on the thumb side of the wrist are swollen and irri- tated. digital divide The gap between those who have access to technology and those who do not. digital manipulation The alteration of digital content, usually text or photographs. digital rights management (DRM) software Software used to protect and manage the rights of creators of digital content, such as art, music, photographs, and movies. digital watermark A subtle alteration of digital content that is not noticeable when the work is viewed or played but that identifies the copyright holder. docking station A device designed to easily connect a portable computer to conventional hardware, such as a keyboard, mouse, monitor, and printer. eco-label A certification, usually by a government agency, that identifies a device as meeting minimal environmental performance specifications. ENERGY STAR A program developed by the U.S. De- partment of Energy and the Environmental Protection Agency (EPA) to encourage the development of energy- saving devices. ergonomic hardware Hardware, typically an input or output device, that is designed to be more ergonomically correct than its nonergonomic counterpart. ergonomics The science of fitting a work environment to the people who work there. ethics Overall standards of moral conduct. etrash Electronic trash or waste, such as discarded com- puter components. green computing The use of computers in an environ- mentally friendly manner. intellectual property rights The legal rights to which creators of original creative works (such as artistic or lit- erary works, inventions, corporate logos, and more) are entitled. Internet addiction The problem of overusing, or being unable to stop using, the Internet. notebook stand A device that elevates the display of a notebook or tablet computer to a better viewing height;
226 CHAPTER 7. COMPUTERS AND SOCIETY
can contain USB ports to connect additional hardware. patent A form of protection for an invention that can be granted by the government; gives exclusive rights of an invention to its inventor for 20 years. plagiarism' Presenting someone else’s work as your own. repetitive stress injury (RSI) A type of injury, such as carpal tunnel syndrome, that is caused by performing the same physical movements over and over again. trademark A word, phrase, symbol, or design that iden- tifies goods or services. Questions True or False
1. All unethical acts are illegal. 2. Changing the background behind a television news- caster to make it appear that he or she is reporting on lo- cation instead of from inside the television studio would be an example of digital manipulation. 3. Carpal tunnel syndrome can be caused by using a com- puter keyboard. 4. As computer use has become more common, the po- tential for stress related to computer use has decreased. 5. Assistive technology is hardware and software de- signed to help all beginning computer users learn how to use a computer. 6. A software program would be protected by copyright- law, while a corporate logo would be protected by trade- mark law. 7. Turning in a copy of a poem you found on a Web site as your original composition for a poetry class assignment is an example of plagiarism. 8. Registering the domain name microsft.com to profit from it would be an act of cybersquatting. 9. The digital divide can be used to describe discrepan- cies in access to technology by individuals within a coun- try, as well as to compare access from country to country. 10. Match each term to its description or example, and write the corresponding number in the blank to the left of each description or example. A. What the symbol © stands for. B. Can vary from another’s depending on his or her val- ues, culture, and so forth. C. A warning about a nonexistent virus spread via e-mail. D. A subtle alteration of digital content that identifies the copyright holder. i. Computer hoax ii. Copyright iii. Digital watermark iv. Ethics
Answers [45]
1. False 2. True 3. True 4. False 5. False 6. copyright; trademark 7. plagiarism 8. cybersquatting 9. digital divide 10. A. ii. B. iv. C. i. D. iii.
[1] http://www.wipo.int/about-ip/en
[2] http://zomboyofficial.com
[3] http://www.wipo.int/trademarks/en/trademarks.html
[4] http://www.ethicalsociety.org/article/19/ about-wes/ethical-culture-our-religious-heritage/ faqs-about-ethical-culture/what-does-ethics-mean
[5] http://www.techterms.com/definition/computerethics
[6] http://www.ikeepsafe.org/cheating-technology/
[7] http://stanford.library.usyd.edu.au/archives/spr2006/ entries/ethics-computer/
[8] http://www.dartmouth.edu/copyright/peer2peer/
[9] http://www.real.com/resources/ youtube-to-mp3-converter/
[10] http://www.storyofmovies.org/common/11041/pdfs/ film_piracy_teachers_guide.pdf
[11] http://www.forbes.com/sites/karstenstrauss/2013/03/06/ tv-and-film-piracy-threatening-an-industry/
[12] Understanding Computers 14th Ed. by Deborah Morley & Charles Parker
[13] http://www.techopedia.com/definition/1678/virus-hoax
[14] http://www.astropix.com/HTML/J_DIGIT/ETHICS. HTM
[15] http://www.lightstalking.com/ what-are-the-ethics-of-digital-manipulation-in-photography/
[16] http://sitemaker.umich.edu/state436/files/Physical_ Issues.htm
[17] http://www.safety.uwa.edu.au/health-wellbeing/ physical/ergonomics/workstation#chairs
[18] http://www.apple.com/about/ergonomics/
[19] Jhonsa, Eric (May 7, 2015). “Fitbit files for IPO, reports strong growth/profits”. Retrieved May 10, 2015.
[20] http://www.ucg.org/entertainment/ how-can-we-cope-world-rapid-change/
7.2. ETHICS 227
[21] http://worksmartlivesmart.com/ future-shock-stress-strategies-technology/
[22] https://georgeinstitute.wordpress.com/2013/09/27/ dealing-with-stress-in-our-fast-paced-ever-changing-world/
[23] http://www.apa.org/monitor/apr00/addiction.aspx
[24] http://www.helpguide.org/articles/addiction/ internet-and-computer-addiction.htm
[25] //http://stopcyberbullying.org/what_is_cyberbullying_ exactly.html
[26] http://www.forbes.com/sites/kenrapoza/2013/10/14/ why-15-of-americans-dont-use-the-internet/
[27] http://iml.jou.ufl.edu/projects/STUDENTS/Lui/index3. htm
[28] http://www.internetworldstats.com/links10.htm
[29] http://hechingerreport.org/content/ technology-skills-scratch-surface-digital-divide_18096/
[30] http://www.pluk.org/Pubs/PLUK_ATguide_269K.pdf
[31] http://www.microsoft.com/enable/at/types.aspx
[32] http://www.humanware.com/en-usa/products/blindness/ braille_embossers_and_writers
[33] http://www.readingrockets.org/article/ assistive-technology-kids-learning-disabilities-overview
[34] http://www.explainingcomputers.com/green.html
[35] http://www.greenpeace.org/ international/en/publications/reports/ Guide-to-Greener-Electronics-15th-edition/
[36] http://www.solar-facts-and-advice.com/solar-cells.html
[37] http://www.chicagorecycling.org/computers.htm
[38] http://www.epa.gov/osw/conserve/materials/ecycling/ donate.htm
[39] http://www.carnegiecyberacademy.com/facultyPages/ environment/issues.html
[40] https://www.dosomething.org/facts/ 11-facts-about-e-waste
[41] http://www.greenpeace.org/international/en/ campaigns/toxics/electronics/the-e-waste-problem/ where-does-e-waste-end-up/
[42] http://search.earth911.com
[43] https://www.eff.org/deeplinks/2005/04/ family-entertainment-and-copyright-act-passes
[44] http://coursemate.cengage.com/CPReader/View/ 9781133114598/default.aspx?eISBN=9781133114598# 3ebb2c54-e38b-4716-ad74-68b62c24cc60
[45] http://ng.cengage.com/static/nb/ui/index.html?nbId= 7345&nbNodeId=1013914#!&parentId=1013951
Chapter 8
Text and image sources, contributors, and licenses
8.1 Text • Introduction to Computer Information Systems Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_Information_
Systems?oldid=3097878 Contributors: CommonsDelinker, JackPotte, QuiteUnusual, Geekgirl, Dave Braunschweig, GroupEkate, Rajeshb- husal10 and Anonymous: 1
• Introduction to Computer Information Systems/Computers in Your Life Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/Computers_in_Your_Life?oldid=3068784 Contributors: Az1568, CommonsDelinker, QuiteUnusual, Tegel, Cic, Harrybrowne1986, Geekgirl, Defender, Jon Snow, Ahnstein, Colorado116, Queso~enwikibooks, Brian3.1415, Carson8tor, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch and Anonymous: 7
• Introduction to Computer Information Systems/What is a Computer? Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/What_is_a_Computer%3F?oldid=3101407 Contributors: Chazz, CommonsDelinker, Denniss, Jack- Potte, QuiteUnusual, Sigma 7, Harrybrowne1986, Geekgirl, Himanis Das, Jon Snow, Arlen Bales, Runner4lyfe, PianoGirl, Catelyn- StarkJonFairplay, Psych4Life, Alangandy, Mmeszaro365 and Anonymous: 6
• Introduction to Computer Information Systems/Computers to Fit Every Need Source: https://en.wikibooks.org/wiki/Introduction_ to_Computer_Information_Systems/Computers_to_Fit_Every_Need?oldid=3088994 Contributors: CommonsDelinker, Cic, Geekgirl, Jon Snow, Volleyballgirl19, Dasteelers76, Leenmcd213, Crackerjack03, Oles7, Zebrachie, Alangandy, CharlieSwitch and Anonymous: 6
• Introduction to Computer Information Systems/Computer Networks and the Internet Source: https://en.wikibooks.org/ wiki/Introduction_to_Computer_Information_Systems/Computer_Networks_and_the_Internet?oldid=3057686 Contributors: Commons- Delinker, QuiteUnusual, Geekgirl, WorldTraveller101, Jamithxx, Sturm und Drang Orb, Harper911, Roverplayer773, Lildrummerboy26, Alangandy, Nfvbkf11 and Anonymous: 1
• Introduction to Computer Information Systems/Computers and Society Source: https://en.wikibooks.org/wiki/Introduction_ to_Computer_Information_Systems/Computers_and_Society?oldid=2756249 Contributors: Cic, Geekgirl, GroupEkate, Groupekelly, GroupETom, Sodayodadude, PoojaS, SanchadelaMancha and Anonymous: 2
• Introduction to Computer Information Systems/Review Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Review?oldid=2756240 Contributors: Cic, Geekgirl and Jon Snow
• Introduction to Computer Information Systems/The System Unit Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/The_System_Unit?oldid=3060265 Contributors: CommonsDelinker, Marcus Cyron, QuiteUnusual, Cic, Geek- girl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Arlen Bales, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Rover- player773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Alangandy, Stormnreign, Carson8tor, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch, Lonescout gorongoron and Anonymous: 6
• Introduction to Computer Information Systems/Storage Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Storage?oldid=3012516 Contributors: Green Giant, CommonsDelinker, Pi zero, QuiteUnusual, Cic, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Arlen Bales, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Syum90, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Brian3.1415, Carson8tor, UA535, N3wGuy72, Nfvbkf11, Stu101-8-1 and Anonymous: 11
• Introduction to Computer Information Systems/Input and Output Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Input_and_Output?oldid=3017263 Contributors: CommonsDelinker, Cic, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Arlen Bales, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Syum90, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFair- play, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Alangandy, Mike Shostak, Brian3.1415, Car- son8tor, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch and Anonymous: 4
• Introduction to Computer Information Systems/System Software Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/System_Software?oldid=3078309 Contributors: CommonsDelinker, Qubodup, QuiteUnusual, Geekgirl,
228
8.1. TEXT 229
GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Arlen Bales, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Syum90, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Neounix, Olives3180, Carson8tor, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch and Anonymous: 7
• Introduction to Computer Information Systems/Application Software Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/Application_Software?oldid=3056233 Contributors: CommonsDelinker, Cic, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Arlen Bales, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Syum90, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Rover- player773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Nicole McDon- agh, GRAND RADION, Brian3.1415, Carson8tor, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch and Anonymous: 4
• Introduction to Computer Information Systems/Computer Networks Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/Computer_Networks?oldid=3041575 Contributors: QuiteUnusual, Cic, Geekgirl, GroupEkate, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Elmograce, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, KevinBarrett15, Brian3.1415, Carson8tor, UA535, N3wGuy72, CharlieSwitch and Anonymous: 6
• Introduction to Computer Information Systems/Internet Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Internet?oldid=3007626 Contributors: CommonsDelinker, Cic, Geekgirl, GroupEkate, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, UA535, CharlieSwitch and Anonymous: 2
• Introduction to Computer Information Systems/Security Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Security?oldid=3034560 Contributors: Tegel, Cic, Geekgirl, Defender, GroupEkate, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Elmograce, Syum90, Sodayodadude, Abefroman42, Pi- anoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Alangandy, Carson8tor, N3wGuy72, Nfvbkf11, Sabguy, Nebrine2000 and Anony- mous: 4
• Introduction to Computer Information Systems/Multimedia Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Multimedia?oldid=3092137 Contributors: CommonsDelinker, Sigma 7, Cic, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, Sanchade- laMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Alangandy, HakanIST, Brian3.1415, UA535, N3wGuy72, Nfvbkf11, Char- lieSwitch, Sunnypants and Anonymous: 5
• Introduction to Computer Information Systems/E-Commerce Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/E-Commerce?oldid=3011587 Contributors: CommonsDelinker, QuiteUnusual, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Syum90, Sodayo- dadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, CommonsDelinquent, Alangandy, Tropicalkitty, Carson8tor, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch and Anonymous: 4
• Introduction to Computer Information Systems/Information Systems Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/Information_Systems?oldid=3066374 Contributors: Green Giant, QuiteUnusual, Sigma 7, Geekgirl, Rotlink, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Harper911, Matiia, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFair- play, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, HakanIST, Brian3.1415, Carson8tor, UA535, N3wGuy72, CharlieSwitch and Anonymous: 10
• Introduction to Computer Information Systems/Program Development Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/Program_Development?oldid=3021352 Contributors: Chazz, Xania, CommonsDelinker, Cic, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Harper911, At- covi, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Brian3.1415, UA535, CharlieSwitch and Anony- mous: 5
• Introduction to Computer Information Systems/Database Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Database?oldid=3050750 Contributors: CommonsDelinker, QuiteUnusual, Tegel, Cic, DivineAlpha, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Harper911, Atcovi, Syum90, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFair- play, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Ah3kal, Alangandy, N3wGuy72, Eaton11 and Anonymous: 9
• Introduction to Computer Information Systems/Computer Security Source: https://en.wikibooks.org/wiki/Introduction_to_ Computer_Information_Systems/Computer_Security?oldid=3027027 Contributors: Chazz, CommonsDelinker, Cic, Geekgirl, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, SanchadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Brian3.1415, UA535, N3wGuy72, Nfvbkf11, CharlieSwitch and Anonymous: 2
• Introduction to Computer Information Systems/Ethics Source: https://en.wikibooks.org/wiki/Introduction_to_Computer_ Information_Systems/Ethics?oldid=3083147 Contributors: QuiteUnusual, Cic, Geekgirl, Leitoxx, GroupEkate, Groupekelly, Jon Snow, Volleyballgirl19, Jamithxx, Runner4lyfe, Sturm und Drang Orb, GroupETom, Colorado116, Harper911, Elmograce, Sodayodadude, Abefroman42, PianoGirl, Leenmcd213, Crackerjack03, PoojaS, Oles7, Roverplayer773, CatelynStarkJonFairplay, Psych4Life, San- chadelaMancha, Queso~enwikibooks, Lildrummerboy26, Zebrachie, Nanatina0912, Stormnreign, Brian3.1415, Carson8tor, UA535, N3wGuy72, Nfvbkf11 and Anonymous: 4
230 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
8.2 Images • File:100_USD_watermark.jpeg Source: https://upload.wikimedia.org/wikipedia/commons/c/c2/100_USD_watermark.jpeg License:
Public domain Contributors: [1] Original artist: Bureau of Engraving & Printing • File:11_Statement_Cash_Flows_Trust_Funds.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/c4/11_Statement_
Cash_Flows_Trust_Funds.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Ladyfwr • File:1328102004_Defragmentation.png Source: https://upload.wikimedia.org/wikipedia/commons/8/80/1328102004_
Defragmentation.png License: CC BY 3.0 Contributors: VistaICO Toolbar Icons Original artist: VistaICO.com • File:1980s_computer_worker,_Centers_for_Disease_Control.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/14/
1980s_computer_worker%2C_Centers_for_Disease_Control.jpg License: Public domain Contributors: http://phil.cdc.gov/phil/details. asp?pid=8159 Original artist: U.S. Centers for Disease Control
• File:2008TICA_Press_Conference_TransAVA_T88_TV_Phone.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/ 46/2008TICA_Press_Conference_TransAVA_T88_TV_Phone.jpg License: CC BY-SA 4.0-3.0-2.5-2.0-1.0 Contributors: Rico Shen Orig- inal artist: Rico Shen
• File:2008_Intel_Developer_Forum_Taiwan_Day2_MID_Keynote_Online_Game_Demonstration.jpg Source: https: //upload.wikimedia.org/wikipedia/commons/a/a6/2008_Intel_Developer_Forum_Taiwan_Day2_MID_Keynote_Online_Game_ Demonstration.jpg License: CC BY-SA 4.0-3.0-2.5-2.0-1.0 Contributors: Rico Shen Original artist: Rico Shen
• File:200_GB_7200_rpm_ide_hard_drive.jpg Source: https://upload.wikimedia.org/wikipedia/commons/ 3/3b/200_GB_7200_rpm_ide_hard_drive.jpg License: Public domain Contributors: http://www. public-domain-image.com/public-domain-images-pictures-free-stock-photos/objects-public-domain-images-pictures/ electronics-devices-public-domain-images-pictures/computer-components-pictures/200-gb-7200-rpm-ide-hard-drive.jpg Original artist: Leon Brooks
• File:2011-06-03-bios.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/13/2011-06-03-bios.jpg License: CC BY 3.0 Contributors: Own work Original artist: Thomas Bresson
• File:3D_printed_Beethoven_(9415625226).jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/af/3D_printed_ Beethoven_%289415625226%29.jpg License: CC BY 2.0 Contributors: 3D printed Beethoven Original artist: Creative Tools from Halmdstad, Sweden
• File:3_states_of_data.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/23/3_states_of_data.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Jasper59
• File:50_percents.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/62/50_percents.svg License: CC0 Contributors: File: 50%.svg Original artist: Ftiercel
• File:5_Stage_Pipeline.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/67/5_Stage_Pipeline.svg License: Public domain Contributors: Own work Original artist: Inductiveload
• File:A1gp_cooper_tires.JPG Source: https://upload.wikimedia.org/wikipedia/commons/5/5e/A1gp_cooper_tires.JPG License: Public domain Contributors: Self-photographed (Original text: Digitalkamera (Sony Cyber-Shot 5.0 Megapixels)) Original artist: Lutz H
• File:AC1-Database_layout.jpg Source: https://upload.wikimedia.org/wikibooks/en/3/3e/AC1-Database_layout.jpg License: Fair use Contributors: ? Original artist: ?
• File:ACR_ResQLink_406MHz_Personal_Locator_Beacon_with_GPS_emergency_PLB_c18ca43690ed11e392db12e25f465f4f_ 8.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/c0/ACR_ResQLink_406MHz_Personal_Locator_Beacon_with_ GPS_emergency_PLB_c18ca43690ed11e392db12e25f465f4f_8.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Tony Webster
• File:ALi_M1541_Motherboard.JPG Source: https://upload.wikimedia.org/wikipedia/commons/2/2a/ALi_M1541_Motherboard.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: AxxaVerKa
• File:ANS700-CPU-board.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/7b/ANS700-CPU-board.jpg License: Pub- lic domain Contributors: Own work Original artist: Henrik Wannheden
• File:ARINC_801_Fiber_Optic_Terminus.png Source: https://upload.wikimedia.org/wikipedia/commons/5/58/ARINC_801_Fiber_ Optic_Terminus.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Sabritec
• File:ARPA1974english.JPG Source: https://upload.wikimedia.org/wikipedia/commons/4/44/ARPA1974english.JPG License: Public domain Contributors: http://commons.wikimedia.org/wiki/File:Arpanet_1974.svg Original artist: Yngvar
• File:ASC_Purple_Supercomputer.jpg_ Source: https://upload.wikimedia.org/wikipedia/commons/9/93/ASC_Purple_ Supercomputer.jpg License: Public domain Contributors: Lawrence Livermore National Laboratory https://asc.llnl.gov/computing_ resources/purple/photogallery/ Original artist: US Government: Lawrence Livermore National Laboratory
• File:A_bus_full_of_USN_tri-athletes.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/78/A_bus_full_of_USN_ tri-athletes.jpg License: Public domain Contributors: http://www.navy.mil/view_ahhphotos.asp?page=30 Original artist: Shane T. McCoy
• File:Aalupi_järv_2013_08.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/95/Aalupi_j%C3%A4rv_2013_08.jpg Li- cense: CC BY-SA 3.0 Contributors: Own work Original artist: Vaido Otsar
• File:Abstract.JPG Source: https://upload.wikimedia.org/wikipedia/commons/5/58/Abstract.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: Adedotun.adebowale
• File:Acer_AC700-1099_Chromebook_2013-12-22_00-39.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f7/Acer_ AC700-1099_Chromebook_2013-12-22_00-39.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: User:OtherKevin
• File:ActiveX_logo.png Source: https://upload.wikimedia.org/wikipedia/commons/c/cb/ActiveX_logo.png License: Public domain Con- tributors: http://www.eltrox.pl/index.php?main_page=document_general_info&products_id=2791 Original artist: Microsoft
8.2. IMAGES 231
• File:Adobe_Acrobat_dot_com_(2010).png Source: https://upload.wikimedia.org/wikipedia/commons/a/a4/Adobe_Acrobat_dot_com_ %282010%29.png License: Public domain Contributors: This image can be extracted from Adobe Reader v9.0 Original artist: Adobe Systems
• File:Adobe_Creative_Suite_v6.0_Icon.png Source: https://upload.wikimedia.org/wikipedia/commons/b/be/Adobe_Creative_Suite_ v6.0_Icon.png License: Public domain Contributors: http://www.photoshopisland.com/sites/default/files/Creative_Suite_6_Master_ Collection_mnemonic_RGB_256px.png Original artist: Adobe
• File:Adobe_Dreamweaver_CS4_icon.png Source: https://upload.wikimedia.org/wikipedia/commons/2/2c/Adobe_Dreamweaver_ CS4_icon.png License: Public domain Contributors: Extracted from Adobe Dreamweaver CS4 Original artist: Adobe Systems
• File:Aeroporto_Porto_11.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/59/Aeroporto_Porto_11.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Manuel de Sousa
• File:Aiga_mail_inverted.svg Source: https://upload.wikimedia.org/wikipedia/commons/d/d3/Aiga_mail_inverted.svg License: Public domain Contributors: AIGA Original artist: US DoT - AIGA
• File:Ajax-vergleich-en.svg Source: https://upload.wikimedia.org/wikipedia/commons/0/0b/Ajax-vergleich-en.svg License: CC BY-SA 3.0 Contributors: https://commons.wikimedia.org/wiki/File%3AAjax-vergleich.svg Original artist: DanielSHaischt, via Wikimedia Com- mons
• File:AluminiumG4.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/e5/AluminiumG4.jpg License: Public domain Con- tributors: ? Original artist: ?
• File:Amazon-icon.png Source: https://upload.wikimedia.org/wikipedia/commons/b/b4/Amazon-icon.png License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Szk7788
• File:Amazon_Box.JPG Source: https://upload.wikimedia.org/wikipedia/commons/5/5b/Amazon_Box.JPG License: Public domain Con- tributors: Own work (Original text: I created this work entirely by myself.) Original artist: David
• File:Amazon_logo.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/aa/Amazon_logo.jpg License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Balajimuthazhagan
• File:Analog-signal-quite-square3.png Source: https://upload.wikimedia.org/wikipedia/commons/9/99/Analog-signal-quite-square3. png License: CC BY-SA 3.0 Contributors: Own work Original artist: Georges.khaznadar
• File:Annotations_Table3.png Source: https://upload.wikimedia.org/wikipedia/commons/6/63/Annotations_Table3.png License: GFDL Contributors: desktop Original artist: deepak0490
• File:Anonymous.png Source: https://upload.wikimedia.org/wikipedia/commons/8/80/Anonymous.png License: CC BY-SA 3.0 Contrib- utors: Own work Original artist: Akshayhallur
• File:Anti-Stop_Online_Piracy_act.png Source: https://upload.wikimedia.org/wikipedia/commons/b/b3/Anti-Stop_Online_Piracy_act. png License: Public domain Contributors: I just gelled the stop sign and wrote the SOPA words. it worked Original artist: Mad Hatter
• File:Apple_Pay_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/b0/Apple_Pay_logo.svg License: Public domain Contributors: http://www.apple.com/apple-pay/ Original artist: Original logo by Apple Inc., vectorized by EuroCarGT
• File:Application_Layer.png Source: https://upload.wikimedia.org/wikipedia/commons/d/d7/Application_Layer.png License: CC BY- SA 3.0 Contributors: Own work Original artist: Chunte7
• File:Artificial.intelligence.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/1c/Artificial.intelligence.jpg License: Pub- lic domain Contributors: http://lifeboat.com/images/artificial.intelligence.jpg Original artist: Alejandro Zorrilal Cruz
• File:Ashdod_QRpedia.png Source: https://upload.wikimedia.org/wikipedia/commons/b/ba/Ashdod_QRpedia.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Victuallers
• File:Assistive_devices_(6235420475).jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/e6/Assistive_devices_ %286235420475%29.jpg License: CC BY 2.0 Contributors: Assistive devices Original artist: Oregon Department of Transportation
• File:Assorted_smartphones.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/53/Assorted_smartphones.jpg License: CC BY-SA 2.0 Contributors: Cropped by uploader from This is madness! (pt. 2) Original artist: ALT1040 from Blogosfera
• File:Astrid_Gruppefremvisning.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/2d/Astrid_Gruppefremvisning.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Astrid Lomholt
• File:Asus_P5K-SEIntel_E6320.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/85/Asus_P5K-SEIntel_E6320.jpg Li- cense: Public domain Contributors: Transferred from en.wikipedia to Commons by Kajasudhakarababu using CommonsHelper. Original artist: Mikeh0303 at English Wikipedia
• File:Augmented_reality_at_Museu_de_Mataró_linking_to_Catalan_Wikipedia_(18).JPG Source: https://upload.wikimedia.org/ wikipedia/commons/5/51/Augmented_reality_at_Museu_de_Matar%C3%B3_linking_to_Catalan_Wikipedia_%2818%29.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: Kippelboy
• File:Avatar-Logo-avatar.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f5/Avatar-Logo-avatar.svg License: Public domain Contributors: Own work Original artist: TheCuriousGnome
• File:Avatar_of_virtual_world.png Source: https://upload.wikimedia.org/wikipedia/commons/8/87/Avatar_of_virtual_world.png Li- cense: CC BY-SA 3.0 Contributors: Own work Original artist: Xjmos
• File:BUSCADO.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/BUSCADO.jpg License: Public domain Contrib- utors: http://www.promositios.com/noticias/fotos//Google-Bing-Yahoo2-np.jpg Original artist: http://www.promositios.com/noticias/ fotos//Google-Bing-Yahoo2-np.jpg
• File:Bandwidth.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f6/Bandwidth.svg License: CC BY 2.5 Contributors: Transferred from en.wikipedia. Original artist: Henrikb4 at en.wikipedia
• File:Barnpaapc.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/56/Barnpaapc.jpg License: CC BY-SA 3.0 Contribu- tors: Own work Original artist: Marisa Ravn
232 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:Bing_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/e/e9/Bing_logo.svg License: Public domain Contributors: The logo may be obtained from microsoft.com/Presspass/gallery/ms-logos.mspx. Converted to SVG and uploaded by GageSkidmore (talk · contribs) of English Wikipedia Original artist: Original logo is made by Microsoft. SVG version is created and uploaded by GageSkidmore (talk · contribs) of English Wikipedia.
• File:Bit_shift.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/63/Bit_shift.svg License: CC-BY-SA-3.0 Contributors: Own work (Inkscape) Original artist: Wojciech Muła
• File:Blaise_Pascal_works_p6.png Source: https://upload.wikimedia.org/wikipedia/commons/6/66/Blaise_Pascal_works_p6.png Li- cense: Public domain Contributors: http://www.archive.org/details/blaisepascal00newy Original artist: Blaise Pascal
• File:BlenderCyclesProceduralEyeballScleraNodes1.png Source: https://upload.wikimedia.org/wikipedia/commons/8/8f/ BlenderCyclesProceduralEyeballScleraNodes1.png License: GPL Contributors: Blender 2.70 Original artist: ?
• File:Blog_(1).jpg_ Source: https://upload.wikimedia.org/wikipedia/commons/4/42/Blog_%281%29.jpg License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Cortega9
• File:Blu-ray_disc_(BD-RE).JPG Source: https://upload.wikimedia.org/wikipedia/commons/a/a3/Blu-ray_disc_%28BD-RE%29.JPG License: Public domain Contributors: Own work Original artist: 159753
• File:Blueprint_for_Everglades_canals1921.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/04/Blueprint_for_ Everglades_canals1921.jpg License: Public domain Contributors: Everglades Digital Library Original artist: Model Land Company, Everglades Drainage District
• File:BouncingRay.png Source: https://upload.wikimedia.org/wikipedia/commons/9/9e/BouncingRay.png License: Attribution Contribu- tors: http://www.ils.uec.ac.jp/~{}dima/CONF/2007/PARIS/50.pdf, Original artist: Dmitrii Kouznetosv
• File:Bouncywikilogo.gif Source: https://upload.wikimedia.org/wikipedia/commons/6/6c/Bouncywikilogo.gif License: CC BY-SA 3.0 Contributors: http://www.uncyclopedia.org/wiki/Image:Bouncywikilogo.gif Original artist: Wikimedia Foundation (edited by Splaka at Uncyclopedia)
• File:Boy_wearing_Oculus_Rift_HMD.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d6/Boy_wearing_Oculus_ Rift_HMD.jpg License: CC BY 3.0 Contributors: Own work Original artist: Skydeas
• File:Braille_text.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/ee/Braille_text.jpg License: CC BY 2.0 Contributors: Flickr Original artist: Ralph Aichinger
• File:Brokenlaptop.png Source: https://upload.wikimedia.org/wikipedia/commons/9/9d/Brokenlaptop.png License: Public domain Con- tributors: Own work Original artist: Bahamut0013
• File:Bus_Topology.png Source: https://upload.wikimedia.org/wikipedia/commons/f/f3/Bus_Topology.png License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Umapathy
• File:Bypassing_Internet_Censorship-Proxy-IE-1.gif_ Source: https://upload.wikimedia.org/wikibooks/en/1/1e/Bypassing_Internet_ Censorship-Proxy-IE-1.gif License: Fair use Contributors: ? Original artist: ?
• File:C4004_two_lines.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b9/C4004_two_lines.jpg License: Public domain Contributors: Transferred from de.wikipedia to Commons by Wdwd using CommonsHelper. Original artist: Peter1912 at German Wikipedia
• File:CDROM.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b0/CDROM.jpg License: CC BY 2.5 Contributors: Trans- ferred from fr.wikipedia to Commons by Padawane. Original artist: The original uploader was Vincent1969 at French Wikipedia
• File:CD_autolev_crop.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d5/CD_autolev_crop.jpg License: CC-BY-SA- 3.0 Contributors: Own work Original artist: Ubern00b
• File:CPT-Databases-Example1MLeagueTeam.svg Source: https://upload.wikimedia.org/wikipedia/commons/9/9b/ CPT-Databases-Example1MLeagueTeam.svg License: CC0 Contributors: Own work Original artist: Pluke
• File:CPT-Programming-FOR-Loop.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/bc/ CPT-Programming-FOR-Loop.svg License: CC0 Contributors: Own work Original artist: Pluke
• File:CPT-Structured_Chart_Selection.svg Source: https://upload.wikimedia.org/wikipedia/commons/7/7d/CPT-Structured_Chart_ Selection.svg License: CC0 Contributors: Own work Original artist: Pluke
• File:CPT-SystemLifeSycle.svg Source: https://upload.wikimedia.org/wikipedia/commons/a/aa/CPT-SystemLifeSycle.svg License: CC0 Contributors: Own work Original artist: Pluke
• File:CPU_supply.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/CPU_supply.jpg License: CC-BY-SA-3.0 Con- tributors: ? Original artist: ?
• File:CS_Venn_Diagram.pdf Source: https://upload.wikimedia.org/wikipedia/commons/0/04/CS_Venn_Diagram.pdf License: CC BY 3.0 Contributors: Own work Original artist: Pfuchs722
• File:Cameratoezicht_monitorruimte.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/db/Cameratoezicht_ monitorruimte.jpg License: Public domain Contributors: Originally from nl.wikipedia; description page is/was here. Original artist: Original uploader was Sanderflight at nl.wikipedia
• File:Campion-CCTV-Camera-CN-7611HS.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b7/ Campion-CCTV-Camera-CN-7611HS.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Amirecoy
• File:Cartoonvirus.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d2/Cartoonvirus.jpg License: Public domain Con- tributors: Own work Original artist: Sarahpetersen
• File:Casediagram.GIF Source: https://upload.wikimedia.org/wikibooks/en/5/59/Casediagram.GIF License: Public domain Contributors: ? Original artist: ?
• File:Chameleon_GIF.GIF Source: https://upload.wikimedia.org/wikipedia/commons/8/8c/Chameleon_GIF.GIF License: CC BY-SA 4.0 Contributors: Own work Original artist: SurreyJohn
8.2. IMAGES 233
• File:Chariot_vert.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/2b/Chariot_vert.svg License: CC BY-SA 3.0 Contrib- utors: Own work Original artist: Toutspeed
• File:Checkbox.png Source: https://upload.wikimedia.org/wikipedia/commons/7/72/Checkbox.png License: Public domain Contributors: Prototype Original artist: User:MeekMark based on jpg version by Wikipedia:User:Dysprosia
• File:Chicote.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/15/Chicote.jpg License: CC-BY-SA-3.0 Contributors: Bo- son WebCam Acer Original artist: Hernansaez
• File:Chronic_fatigue_syndrome.JPG Source: https://upload.wikimedia.org/wikipedia/commons/c/cd/Chronic_fatigue_syndrome.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: Shanghai killer whale
• File:Chuck_Norris_-_Google_Search.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/de/Chuck_Norris_-_Google_ Search.jpg License: CC BY-SA 2.0 Contributors: http://www.flickr.com/photos/greyloch/2261884042/ Original artist: http://www.flickr. com/photos/greyloch/ By greyloch, No real name given
• File:Cis3.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/ed/Cis3.jpg License: Public domain Contributors: No machine- readable source provided. Own work assumed (based on copyright claims). Original artist: No machine-readable author provided. Denisgomes assumed (based on copyright claims).
• File:Cisco_Model_EPC3010.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d7/Cisco_Model_EPC3010.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Kjetil Ree
• File:Click.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/58/Click.svg License: Public domain Contributors: http: //www.sonypictures.com/movies/click Original artist: Diseñadores publicitarios
• File:Cloud_For_Permanent_Digital_Storage.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f2/Cloud_For_ Permanent_Digital_Storage.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Tani12
• File:Cloud_Services.gif Source: https://upload.wikimedia.org/wikipedia/commons/6/60/Cloud_Services.gif License: CC BY 3.0 Con- tributors: Own work using Microsoft Office 2007 Power Point; Man, Software, Cloud, Computer Server: Microsoft Office Clip Art (used with permission of Microsoft)This way to Microsoft Original artist: Sdhabeger
• File:Coaxial_cable_cutaway.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f4/Coaxial_cable_cutaway.svg License: CC BY 3.0 Contributors: Own work Original artist: Tkgd2007
• File:Computer-blue.svg Source: https://upload.wikimedia.org/wikipedia/commons/d/db/Computer-blue.svg License: CC0 Contributors: OpenClipart Original artist: OpenClipart
• File:Computer-globe.svg Source: https://upload.wikimedia.org/wikipedia/commons/d/d1/Computer-globe.svg License: CC BY-SA 2.5 Contributors: Transferred from en.wikipedia by SreeBot Original artist: DTR at en.wikipedia
• File:Computer_Security.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/77/Computer_Security.jpg License: CC BY 2.0 Contributors: http://www.flickr.com/photos/intelfreepress/7853146846/sizes/o/in/photostream/ Original artist: Intel Free Press
• File:Computer_Workstation_Variables_cleanup.png Source: https://upload.wikimedia.org/wikipedia/commons/c/c0/Computer_ Workstation_Variables_cleanup.png License: CC0 Contributors: Own work Original artist: Yamavu
• File:Computer_locked.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d3/Computer_locked.jpg License: CC BY 2.0 Contributors: Flickr: G4 Security Original artist: Juan Pablo Olmo
• File:Computer_mouse-2005.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f9/Computer_mouse-2005.jpg License: Public domain Contributors: Own work Original artist: László Szalai (Beyond silence)
• File:Computer_n_screen.svg Source: https://upload.wikimedia.org/wikipedia/commons/7/77/Computer_n_screen.svg License: LGPL Contributors: All Crystal icons were posted by the author as LGPL on kde-look Original artist: Everaldo Coelho and YellowIcon
• File:Computernetwork.png Source: https://upload.wikimedia.org/wikipedia/commons/d/d1/Computernetwork.png License: Public do- main Contributors: Own work Original artist: Joshap
• File:Copyright.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/b0/Copyright.svg License: Public domain Contributors: see below Original artist: Unknown<a href='//www.wikidata.org/wiki/Q4233718' title='wikidata:Q4233718'><img alt='wikidata: Q4233718' src='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/20px-Wikidata-logo.svg.png' width='20' height='11' srcset='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/30px-Wikidata-logo. svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/40px-Wikidata-logo.svg.png 2x' data-file-width='1050' data-file-height='590' /></a> / see below
• File:CorelDRAW_Graphics_Suite_X6_Logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/9/9c/CorelDRAW_ Graphics_Suite_X6_Logo.svg License: Public domain Contributors: http://www.corel.com/static/product_content/cdgs/x6/ CDGSX6_ReviewersGuide_de.pdf Original artist: Unknown<a href='//www.wikidata.org/wiki/Q4233718' title='wikidata: Q4233718'><img alt='wikidata:Q4233718' src='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo. svg/20px-Wikidata-logo.svg.png' width='20' height='11' srcset='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/ Wikidata-logo.svg/30px-Wikidata-logo.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/ 40px-Wikidata-logo.svg.png 2x' data-file-width='1050' data-file-height='590' /></a>
• File:Cosmos_debugger_in_action.png Source: https://upload.wikimedia.org/wikipedia/commons/1/1a/Cosmos_debugger_in_action. png License: CC0 Contributors: https://cosmos.codeplex.com/ Original artist: Chad Hower
• File:Craigslist.svg Source: https://upload.wikimedia.org/wikipedia/commons/c/c6/Craigslist.svg License: Public domain Contributors: Own work Original artist: CoolKid1993
• File:Credit-cards.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4f/Credit-cards.jpg License: CC-BY-SA-3.0 Con- tributors: sxc.hu Original artist: Lotus Head from Johannesburg, Gauteng, South Africa
• File:Crystal_Clear_app_Internet_Connection_Tools.png_ Source: https://upload.wikimedia.org/wikipedia/commons/5/59/Crystal_ Clear_app_Internet_Connection_Tools.png License: LGPL Contributors: All Crystal Clear icons were posted by the author as LGPL on kde-look; Original artist: Everaldo Coelho and YellowIcon;
234 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:Crystal_Clear_app_Internet_Connection_Tools.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/65/Crystal_ Clear_app_Internet_Connection_Tools.svg License: LGPL Contributors: Crystal Clear app Internet Connection Tools.png Original artist: Everaldo Coelho YellowIcon
• File:Cyberbullying.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d5/Cyberbullying.jpg License: GFDL Contributors: http://noalciberacoso.blogspot.com Original artist: Internetsinacoso
• File:Cyberstalking.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/27/Cyberstalking.jpg License: GFDL Contributors: http://noalciberacoso.blogspot.com/ Original artist: Internetsinacoso
• File:DAR_v_DIU.JPG Source: https://upload.wikimedia.org/wikipedia/commons/3/3b/DAR_v_DIU.JPG License: CC0 Contributors: Own work Original artist: Jasper59
• File:DATA_MINING.JPG Source: https://upload.wikimedia.org/wikipedia/commons/0/07/DATA_MINING.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: Hiladamouss
• File:DB2_Client_Connections.png Source: https://upload.wikimedia.org/wikipedia/commons/9/95/DB2_Client_Connections.png Li- cense: CC BY-SA 3.0 Contributors: Own work Original artist: Scifipete
• File:DC3_seal.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/c8/DC3_seal.jpg License: Public domain Contributors: ? Original artist: ?
• File:DS0074_1_lq.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/9f/DS0074_1_lq.jpg License: Public domain Con- tributors: http://en.wikipedia.org/wiki/Image:DS0074_1_lq.jpg Original artist: Ali Emamdjomeh
• File:Database-excel.png Source: https://upload.wikimedia.org/wikipedia/commons/1/16/Database-excel.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Oftcc
• File:Database_models.jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/3b/Database_models.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Marcel Douwe Dekker
• File:Datawalker_LA18.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/5f/Datawalker_LA18.jpg License: Public do- main Contributors: Own work Original artist: Datawalk
• File:Deadline_!_(7320523564).jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/98/Deadline_%21_%287320523564% 29.jpg License: CC BY 2.0 Contributors: Deadline ! Original artist: Craig Sunter from Manchester, UK
• File:Dec_pdp-6.lg.jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/31/Dec_pdp-6.lg.jpg License: CC BY 3.0 Contribu- tors: archive.computerhistory.org Original artist: Computer History Museum
• File:Deepin_12.12_Desktop_Screenshot.png Source: https://upload.wikimedia.org/wikipedia/commons/d/dd/Deepin_12.12_ Desktop_Screenshot.png License: CC BY-SA 1.0 Contributors: http://www.webupd8.org/2013/06/linux-deepin-1212-released-with-new. html Original artist: WebUpd8.org
• File:Dial_up_modem_noises.ogg Source: https://upload.wikimedia.org/wikipedia/commons/3/33/Dial_up_modem_noises.ogg License: Public domain Contributors: https://www.youtube.com/watch?v=gsNaR6FRuO0 Original artist: William Termini
• File:Die_386dx33.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4d/Die_386dx33.jpg License: Public domain Con- tributors: Foto von mir gemacht Original artist: myself
• File:Different_Ways_to_Use_Psychographic_Data_in_Online_Marketing.png Source: https://upload.wikimedia.org/wikipedia/ commons/a/a7/Different_Ways_to_Use_Psychographic_Data_in_Online_Marketing.png License: CC BY-SA 4.0 Contributors: Own work Original artist: Karlhain
• File:Digital.signal.png Source: https://upload.wikimedia.org/wikipedia/commons/e/e1/Digital.signal.png License: Public domain Con- tributors: ? Original artist: ?
• File:Digital_Camera.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/2c/Digital_Camera.svg License: CC0 Contribu- tors: Open clip Art Library image’s page Original artist: AJ
• File:Disassembled_digital_camera.jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/3e/Disassembled_digital_camera. jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Lawe
• File:Disc_Crack_From_Case.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/93/Disc_Crack_From_Case.jpg Li- cense: Public domain Contributors: Own work Original artist: CRTGAMER
• File:Disk-structure.svg Source: https://upload.wikimedia.org/wikipedia/commons/d/d7/Disk-structure.svg License: Public domain Con- tributors: Own work Original artist: MistWiz
• File:Dropbox_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/Dropbox_logo.svg License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Polda18
• File:Drum_scanner.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0c/Drum_scanner.jpg License: CC-BY-SA-3.0 Contributors: Own work Original artist: Stefan Kühn
• File:Dsky.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/e2/Dsky.jpg License: Public domain Contributors:
• eigene Arbeit • own work
Original artist: Brandrodungswanderfeldhackbau • File:DuckDuckGo_zero-click_info.png Source: https://upload.wikimedia.org/wikipedia/commons/4/41/DuckDuckGo_zero-click_
info.png License: Copyrighted free use Contributors: http://duckduckgo.com/?q=javascript+settimeout Original artist: Tuxman • File:DynaFile_Index_Browser_-_Human_Resources_Example.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/dd/
DynaFile_Index_Browser_-_Human_Resources_Example.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: OnlineDocumentManagement
8.2. IMAGES 235
• File:E-Waste_Landfill.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/90/E-Waste_Landfill.jpg License: CC BY-SA 2.0 Contributors: E-waste recycling in Ann Arbor Original artist: George Hotelling from Canton, MI, United States
• File:E-Сommerce_center_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/e/ef/E-%D0%A1ommerce_center_ logo.svg License: Public domain Contributors: http://www.ecc.kz Original artist: E-commerce center
• File:E4000-back.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/78/E4000-back.jpg License: CC BY-SA 3.0 Contrib- utors: Own work Original artist: Shieldforyoureyes Dave Fischer
• File:EBay_former_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/1/11/EBay_former_logo.svg License: Public do- main Contributors: Transferred from en.wikipedia to Commons using CommonsHelper. Original artist: The original uploader was KUsam at English Wikipedia
• File:ERP_Modules.png Source: https://upload.wikimedia.org/wikipedia/commons/1/12/ERP_Modules.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Shing Hin Yeung
• File:ETC_Ion_lighting_console.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/17/ETC_Ion_lighting_console.jpg Li- cense: Attribution Contributors: Own work Original artist: User:KeepOnTruckin
• File:EarlyComptometerKeyboard.png Source: https://upload.wikimedia.org/wikipedia/commons/b/b3/EarlyComptometerKeyboard. png License: Public domain Contributors: Own work Original artist: Ezrdr
• File:Editing_Wikipedia,_pixelated_signature_icon.png Source: https://upload.wikimedia.org/wikipedia/commons/b/bc/Editing_ Wikipedia%2C_pixelated_signature_icon.png License: CC BY-SA 3.0 Contributors: Wikipedia Original artist: Wikipedia editors
• File:Eff_spying_eagle.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/9c/Eff_spying_eagle.jpg License: CC BY 3.0 us Contributors: http://www.eff.org/nsa Original artist: EFF’s logo for our case against the government seeking to stop the illegal spying operation run by the NSA. For more information: www.eff.org/nsa
• File:Electronic_Flight_Bag.JPG Source: https://upload.wikimedia.org/wikipedia/commons/7/7c/Electronic_Flight_Bag.JPG License: CC BY-SA 4.0 Contributors: Own work Original artist: UA535
• File:Electronic_surveillance_-a.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/6d/Electronic_surveillance_-a.jpg Li- cense: Public domain Contributors: http://www.news.navy.mil/view_ahhphotos.asp?page=65 Original artist: Shane T. McCoy
• File:Elephpant.png Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/Elephpant.png License: GPL Contributors: http: //www.elroubio.net/?p=adopt_an_elephpant. Transferred from en.wikibooks; transferred to Commons by User:Adrignola using CommonsHelper. Original artist: El Roubio. Original uploader was Banzaimonkey at en.wikibooks
• File:EliteCAD_B2C.png Source: https://upload.wikimedia.org/wikipedia/commons/3/3e/EliteCAD_B2C.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Stefsabi
• File:Email_icon_crystal.png Source: https://upload.wikimedia.org/wikipedia/commons/7/74/Email_icon_crystal.png License: Public domain Contributors: Own work Original artist: User:Pianopianissimo
• File:Email_tinted_on_dark_gray.png Source: https://upload.wikimedia.org/wikipedia/commons/0/05/Email_tinted_on_dark_gray. png License: CC BY-SA 3.0 Contributors: Own work Original artist: Cybersprocketlabs
• File:Empresariobaixa.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/2d/Empresariobaixa.jpg License: Public domain Contributors: Own work Original artist: CTBC
• File:Encryption_-_decryption.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/bf/Encryption_-_decryption.svg Li- cense: CC-BY-SA-3.0 Contributors: based on png version originally uploaded to the English-language Wikipedia by mike40033, and moved to the Commons by MichaelDiederich. Original artist: odder
• File:Enterprise_Architecture_Waterfall_Model.gif Source: https://upload.wikimedia.org/wikipedia/commons/7/73/Enterprise_ Architecture_Waterfall_Model.gif License: Public domain Contributors: Enterprisearchitecture.nih.gov Original artist: NIH
• File:Ethernet_cable._SAM.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/18/Ethernet_cable._SAM.jpg License: CC BY-SA 4.0 Contributors: Own work Original artist: Salvador alc
• File:External_hard_drives.jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/3e/External_hard_drives.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: TonyTheTiger
• File:FBI_analyst.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/07/FBI_analyst.jpg License: Public domain Contribu- tors: FBI Photosimage source Original artist: not stated
• File:FBI_anti_piracy.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f5/FBI_anti_piracy.jpg License: Public domain Contributors: FBI.gov Original artist: FBI
• File:FIiber_optic_DLightposter01.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f6/FIiber_optic_DLightposter01. jpg License: Public domain Contributors: No machine-readable source provided. Own work assumed (based on copyright claims). Original artist: No machine-readable author provided. 12Gooner89 assumed (based on copyright claims).
• File:FPL’{}s_Computer_lab.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/FPL%27s_Computer_lab.jpg Li- cense: CC BY-SA 3.0 Contributors: Own work Original artist: Shirley Ku
• File:FaceTime_Yosemite.svg Source: https://upload.wikimedia.org/wikipedia/commons/e/e2/FaceTime_Yosemite.svg License: Public domain Contributors: Own work Original artist: Apple Inc.
• File:Facebook_Logo_on_Monitor.jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/3f/Facebook_Logo_on_Monitor. jpg License: CC BY 3.0 Contributors: Own work Original artist: Flohuels
• File:Facebook_icon.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/82/Facebook_icon.jpg License: Public domain Contributors: Facebook.com Original artist: Facebook
• File:Favoriting.com_RSS_Channels.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/ec/Favoriting.com_RSS_ Channels.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Remixesweb
• File:Final_Cut_Pro_X.png Source: https://upload.wikimedia.org/wikipedia/commons/f/f2/Final_Cut_Pro_X.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Bullon94
236 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:Fingerprint_-_Central_Pocket_Loop_Whorl.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/13/Fingerprint_-_ Central_Pocket_Loop_Whorl.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Saurabh R. Patil
• File:Fingerprint_and_retinal_scan.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/83/Fingerprint_and_retinal_scan. jpg License: Public domain Contributors: Link Direct Original artist: Transportation Security Administration
• File:Fire-im.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/01/Fire-im.jpg License: GPL Contributors: http:// screenshots.en.softonic.com/en/scrn/14000/14164/fire-15.jpg Original artist: Fire-team
• File:Firewall.png Source: https://upload.wikimedia.org/wikipedia/commons/5/5b/Firewall.png License: CC BY-SA 3.0 Contributors: Feito por mim Original artist: Bruno Pedrozo
• File:Firewall_(networking).png Source: https://upload.wikimedia.org/wikipedia/commons/3/38/Firewall_%28networking%29.png Li- cense: Public domain Contributors: Own work Original artist: Luis F. Gonzalez
• File:Fitibit_Flex.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/ca/Fitibit_Flex.jpg License: CC BY-SA 3.0 Contribu- tors: Own work Original artist: MorePix
• File:Flowchart_procedural_programming.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/5f/Flowchart_procedural_ programming.svg License: CC BY-SA 3.0 Contributors: Own work Original artist: User:Kayau
• File:Flower_stock_photo.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4b/Flower_stock_photo.jpg Li- cense: Public domain Contributors: http://www.public-domain-image.com/public-domain-images-pictures-free-stock-photos/ flora-plants-public-domain-images-pictures/flowers-public-domain-images-pictures/flower-stock-photo.jpg Original artist: Marius Iordache
• File:Flowgorithm_Shapes.png Source: https://upload.wikimedia.org/wikipedia/commons/7/7e/Flowgorithm_Shapes.png License: Pub- lic domain Contributors: Own work Original artist: DevinCook
• File:Fortran_acs_cover.jpeg Source: https://upload.wikimedia.org/wikipedia/commons/0/07/Fortran_acs_cover.jpeg License: Public domain Contributors: en:File:Fortran acs cover.jpeg Original artist: original uploader was en:User:Muhandis
• File:Four-Level-Pyramid-model.png Source: https://upload.wikimedia.org/wikipedia/commons/d/dd/Four-Level-Pyramid-model.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Compo
• File:GPS_Satellite_NASA_art-iif.crop.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/25/GPS_Satellite_NASA_ art-iif.crop.jpg License: Public domain Contributors:
• GPS_Satellite_NASA_art-iif.jpg Original artist: GPS_Satellite_NASA_art-iif.jpg: created by NASA • File:Gambas-2.14_code-editor.png Source: https://upload.wikimedia.org/wikipedia/commons/9/9f/Gambas-2.14_code-editor.png
License: GPL Contributors: screenshot of free software Gambas Original artist: Gambas is designed by Benoît Min- isini; screenshot was uploaded by De.Nobelium (<a href='//commons.wikimedia.org/w/index.php?title=User_talk:De. Nobelium,<span>,&,</span>,action=edit,<span>,&,</span>,redlink=1' class='new' title='User talk:De.Nobelium (page does not exist)'>talk</a>) 11:14, 14 July 2009 (UTC)
• File:Global_Bitcoin.png Source: https://upload.wikimedia.org/wikipedia/commons/3/32/Global_Bitcoin.png License: CC BY-SA 4.0 Contributors: Own work Original artist: CodyHofstetter
• File:Global_Digital_Divide1.png Source: https://upload.wikimedia.org/wikipedia/commons/b/bd/Global_Digital_Divide1.png License: Public domain Contributors: Transferred from en.wikipedia to Commons by Delemon using CommonsHelper. Original artist: Dakman5 at English Wikipedia
• File:Globe.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/fa/Globe.svg License: Public domain Contributors: Own work, based on shoreline data from GSHHS (“crude” level), a public-domain source. Original artist: The original uploader was Augiasstallputzer at [[::| Wikimedia Commons]]
• File:Gmail_logo.png Source: https://upload.wikimedia.org/wikipedia/commons/0/0a/Gmail_logo.png License: Public domain Contribu- tors: Transferred from en.wikipedia to Commons. Original artist: Google
• File:Gnome-audio-input-microphone.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/5a/ Gnome-audio-input-microphone.svg License: CC BY-SA 3.0 Contributors: HTTP / FTP Original artist: GNOME icon artists
• File:Gnome-dev-printer.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/5d/Gnome-dev-printer.svg License: LGPL Contributors: http://ftp.gnome.org/pub/GNOME/sources/gnome-themes-extras/0.9/gnome-themes-extras-0.9.0.tar.gz Original artist: David Vignoni
• File:Gnome-dev-removable.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/58/Gnome-dev-removable.svg License: LGPL Contributors: http://ftp.gnome.org/pub/GNOME/sources/gnome-themes-extras/0.9/gnome-themes-extras-0.9.0.tar.gz Original artist: David Vignoni
• File:Gnome-preferences-desktop-keyboard-shortcuts.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/29/ Gnome-preferences-desktop-keyboard-shortcuts.svg License: CC BY-SA 3.0 Contributors: HTTP / FTP Original artist: GNOME icon artists
• File:Google_Chrome_icon_(2011).png Source: https://upload.wikimedia.org/wikipedia/commons/8/87/Google_Chrome_icon_ %282011%29.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Umut159
• File:Google_Drive_Logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/7/75/Google_Drive_Logo.svg License: Public domain Contributors: Own work Original artist: Marce79
• File:Google_web_search_tr.png Source: https://upload.wikimedia.org/wikipedia/commons/c/ce/Google_web_search_tr.png License: Public domain Contributors: http://www.google.com.tr/ Original artist: Google
• File:Google_wordmark.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/fe/Google_wordmark.svg License: Public do- main Contributors: ? Original artist: ?
• File:Grainger_logo.gif Source: https://upload.wikimedia.org/wikipedia/commons/6/64/Grainger_logo.gif License: Public domain Con- tributors: Transferred from en.wikipedia to Commons. (Original Image) Original artist: The original uploader was Loganlogn at English Wikipedia
8.2. IMAGES 237
• File:Greek_letter_omega_serif+sans.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/62/Greek_letter_omega_serif% 2Bsans.svg License: Public domain Contributors: recreated from Image:greek_letter_omega.png as SVG using Inkscape and Free UCS Outline Fonts Original artist: kuhlix
• File:Green_50x75.png_ Source: https://upload.wikimedia.org/wikibooks/en/6/69/Green_50x75.png License: Cc-by-sa-3.0 Contributors: Own work. Original artist: William Wilson
• File:Gyro.gif Source: https://upload.wikimedia.org/wikipedia/commons/8/88/Gyro.gif License: Public domain Contributors: Transferred from en.wikibooks to Commons. Original artist: KieranMaher at English Wikibooks
• File:HDMI-Connector.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/c2/HDMI-Connector.jpg License: Public do- main Contributors: Own work Original artist: Evan-Amos
• File:HP_Presario_F700.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/25/HP_Presario_F700.jpg License: CC BY- SA 3.0 Contributors: Own work Original artist: JCRules
• File:HP_Tablet_PC_running_Windows_XP_(Tablet_PC_edition)_(2006).jpg Source: https://upload.wikimedia.org/wikipedia/ commons/8/82/HP_Tablet_PC_running_Windows_XP_%28Tablet_PC_edition%29_%282006%29.jpg License: Public domain Contributors: Own work (I took this photo) Original artist: Janto Dreijer
• File:Handheld_iris_scanner.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/02/Handheld_iris_scanner.jpg License: Public domain Contributors:
• DoD_Biometrics_Consortium_Conference_13_Sep_2007.pdf Original artist: DoD_Biometrics_Consortium_Conference_13_Sep_2007.pdf: Unknown
• File:Hannover-Messe_2012_by-RaBoe_069.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/21/Hannover-Messe_ 2012_by-RaBoe_069.jpg License: CC BY-SA 3.0 de Contributors: von Wikipedia-User: Ra Boe Original artist: © Ra Boe / Wikipedia
• File:Hard_at_work_in_the_Tampabay_Social_Media_Center._I_was_able_to_finally_meet_some_tweeps!.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0e/Hard_at_work_in_the_Tampabay_Social_Media_Center._I_was_able_to_ finally_meet_some_tweeps%21.jpg License: CC BY 2.0 Contributors: Flickr: hard at work in the #Tampabay Social Media Center. I was able to finally meet some tweeps! Original artist: Robert Neff
• File:Hard_disk_head.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/75/Hard_disk_head.jpg License: CC BY 2.0 Contributors: ? Original artist: ?
• File:Hard_drive-en.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/52/Hard_drive-en.svg License: CC-BY-SA-3.0 Contributors: Own work, based on the public domain image Image:Hdd od srodka.jpg. Image renamed from Image:Hard drive.svg Original artist: Surachit
• File:Headphones_1.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/40/Headphones_1.jpg License: CC-BY-SA-3.0 Contributors: No machine-readable source provided. Own work assumed (based on copyright claims). Original artist: No machine-readable author provided. PJ assumed (based on copyright claims).
• File:Holographic_Data_Storage.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/6b/Holographic_Data_Storage.svg License: CC-BY-SA-3.0 Contributors: Own work Original artist: Surachit
• File:Html5-source-code.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/b0/Html5-source-code.svg License: Public domain Contributors:
• Html5-source-code.png Original artist: Html5-source-code.png: Akabe • File:IBM_Watson.PNG Source: https://upload.wikimedia.org/wikipedia/commons/2/22/IBM_Watson.PNG License: CC BY-SA 3.0
Contributors: Own work Original artist: Clockready • File:IOS_9_Logo.png Source: https://upload.wikimedia.org/wikipedia/commons/8/86/IOS_9_Logo.png License: Public domain Contrib-
utors: https://developer.apple.com/ios/ Original artist: Apple Inc. • File:IPO_Diagram.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/5f/IPO_Diagram.svg License: CC BY-SA 3.0 Con-
tributors: Own work Original artist: Kayau • File:IPad_&_iMac.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b7/IPad_%26_iMac.jpg License: CC BY-SA 3.0
Contributors: Own work Original artist: Tom Murphy • File:IPad_Mini_in_Pivot_Case.JPG Source: https://upload.wikimedia.org/wikipedia/commons/8/8d/IPad_Mini_in_Pivot_Case.JPG
License: CC BY-SA 4.0 Contributors: Own work Original artist: UA535 • File:IPad_Mini_in_Pivot_Case_(Back).JPG Source: https://upload.wikimedia.org/wikipedia/commons/7/75/IPad_Mini_in_Pivot_
Case_%28Back%29.JPG License: CC BY-SA 4.0 Contributors: Own work Original artist: UA535 • File:IPads_at_JA_Tech_Center.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/1b/IPads_at_JA_Tech_Center.jpg
License: CC BY-SA 3.0 Contributors: Own work Original artist: Ewettach • File:Icon_search_updates_96x96.png Source: https://upload.wikimedia.org/wikipedia/commons/a/a8/Icon_search_updates_96x96.
png License: CC0 Contributors: Own work Original artist: Devcore • File:Image_7_Information_Relationship_Model.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/e9/Image_7_
Information_Relationship_Model.jpg License: CC BY 3.0 Contributors: Own work Original artist: Jamessantangelo • File:Image_removed_DMCA.png Source: https://upload.wikimedia.org/wikipedia/commons/4/44/Image_removed_DMCA.png Li-
cense: CC BY-SA 3.0 Contributors: Own work Original artist: Lexein • File:Img_28111_symbian_os.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/a3/Img_28111_symbian_os.jpg License:
CC BY-SA 3.0 Contributors: Own work Original artist: Reufast • File:Information_icon.svg Source: https://upload.wikimedia.org/wikipedia/commons/3/35/Information_icon.svg License: Public do-
main Contributors: en:Image:Information icon.svg Original artist: El T
238 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:Intel_CPU_Core_i7_2600K_Sandy_Bridge_top.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/6c/Intel_CPU_ Core_i7_2600K_Sandy_Bridge_top.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Eric Gaba (Sting - fr:Sting)
• File:Intel_X25-M_Solid-State_Drive.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d7/Intel_X25-M_Solid-State_ Drive.jpg License: CC BY 2.0 Contributors: Flickr: Intel X25-M SATA Solid-State Drive (SSD) Original artist: Intel Free Press
• File:Interactive_table_at_Ideen_2020_exhibition_2013-04-16_09.27.08.jpg Source: https://upload.wikimedia.org/wikipedia/ commons/5/5a/Interactive_table_at_Ideen_2020_exhibition_2013-04-16_09.27.08.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Daniel Mietchen
• File:Internet.png_ Source: https://upload.wikimedia.org/wikipedia/commons/a/ad/Internet.png License: Public domain Contributors: Own work Original artist: Jcarranza
• File:Internet_addiction.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/6a/Internet_addiction.jpg License: CC BY-SA 2.0 Contributors: we swarm Original artist: Sam Wolff from Phoenix, USA
• File:Internet_map_1024.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d2/Internet_map_1024.jpg License: CC BY 2.5 Contributors: Originally from the English Wikipedia; description page is/was here. Original artist: The Opte Project
• File:Iphone_2.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/a2/Iphone_2.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: DanielZanetti
• File:Irecosector_ja.png Source: https://upload.wikimedia.org/wikipedia/commons/9/9e/Irecosector_ja.png License: CC-BY-SA-3.0 Contributors: Own work Original artist: Kotoito
• File:Japan_road_sign_201-2.svg Source: https://upload.wikimedia.org/wikipedia/commons/9/96/Japan_road_sign_201-2.svg License: Public domain Contributors: 2 Original artist: Monaneko
• File:Japanese_teenager_with_her_mobile_phone.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/2a/Japanese_ teenager_with_her_mobile_phone.jpg License: CC BY 2.0 Contributors: [ Keitai Culture] Original artist: scion_cho from Quezon City, Philippines
• File:Java_Rich_Internet_Applications.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/13/Java_Rich_Internet_ Applications.jpg License: Public domain Contributors: Canoo Engineering AG Original artist: Felix Schrape
• File:John_E_Fry_Steadicam_Operator_UK.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/16/John_E_Fry_ Steadicam_Operator_UK.jpg License: Public domain Contributors: Own work Original artist: Fryfilm2000
• File:Joy.svg Source: https://upload.wikimedia.org/wikipedia/commons/4/44/Joy.svg License: CC-BY-SA-3.0 Contributors: This is new version of previously placed by me File:Joy.png on 2 November 2004 Original artist: Piotr Michał Jaworski; Poland/Poznań
• File:Ken-A-Vision’{}s_FlexCam_2_document_camera_connected_to_a_laptop_computer.png Source: https://upload.wikimedia. org/wikipedia/commons/5/52/Ken-A-Vision%27s_FlexCam_2_document_camera_connected_to_a_laptop_computer.png License: CC BY-SA 3.0 Contributors: Own work Previously published: http://ken-a-vision.com/wp-content/uploads/flexcam-laptop.png Original artist: Ken-A-Vision
• File:Kmail.png Source: https://upload.wikimedia.org/wikipedia/commons/3/3e/Kmail.png License: GPL Contributors: Image taken by Patrick Hanft Original artist: KDE, Patrick Hanft
• File:LTE-Logo.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/5d/LTE-Logo.jpg License: Public do- main Contributors: http://www.4gamericas.org/index.cfm?fuseaction=page§ionid=249 Original artist: Unknown<a href='//www.wikidata.org/wiki/Q4233718' title='wikidata:Q4233718'><img alt='wikidata:Q4233718' src='https://upload. wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/20px-Wikidata-logo.svg.png' width='20' height='11' srcset='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/30px-Wikidata-logo.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/40px-Wikidata-logo.svg.png 2x' data-file-width='1050' data-file-height='590' /></a>
• File:Lake_Contours_and_touchscreen_laptop_interface.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/45/Lake_ Contours_and_touchscreen_laptop_interface.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Binksternet
• File:Laptop-hard-drive-exposed.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f8/Laptop-hard-drive-exposed.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Evan-Amos
• File:Laptop.svg Source: https://upload.wikimedia.org/wikipedia/commons/d/d4/Laptop.svg License: LGPL Contributors: All Crystal Clear icons were posted by the author as LGPL on kde-look; Original artist: Everaldo Coelho and YellowIcon;
• File:Laser_printer.png_ Source: https://upload.wikimedia.org/wikipedia/commons/e/e5/Laser_printer.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Greenhedgehog
• File:Lemote_computers.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/8b/Lemote_computers.jpg License: CC BY- SA 3.0 Contributors: Own work Original artist: Bleakgadfly
• File:Life’{}s_more_fun_when_you_are_organized.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/9a/Life%27s_ more_fun_when_you_are_organized.jpg License: CC BY-SA 2.0 Contributors: http://www.flickr.com/photos/dkalo/4540748416/ Origi- nal artist: Dimitris Kalogeropoylos
• File:Lifejacket_Instructions.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/61/Lifejacket_Instructions.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: AlMare
• File:LiftFan-F35B_(CAD).jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0b/LiftFan-F35B_%28CAD%29.jpg Li- cense: Public domain Contributors: http://video.onset.freedom.com/nwfdn/k81dt7-valp.pdf Original artist: Brigadier General Charles R.Davis, USAF
• File:Linksys_NSLU2.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/51/Linksys_NSLU2.jpg License: Public domain Contributors: Own work Original artist: Michael Höchbauer
• File:Logitech-usb-speakers.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/57/Logitech-usb-speakers.jpg License: Public domain Contributors: Own work Original artist: Evan-Amos
8.2. IMAGES 239
• File:Logitech_Gaming-Keyboard_G15.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/54/Logitech_ Gaming-Keyboard_G15.jpg License: Public domain Contributors: Originally from de.wikipedia; description page is/was here. Original artist: Original uploader was Der Franke at de.wikipedia
• File:Logo_estrela5.png Source: https://upload.wikimedia.org/wikipedia/commons/3/3a/Logo_estrela5.png License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Leonardo Araujo
• File:MOL_Official_Logo.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/be/MOL_Official_Logo.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Molpr
• File:Macintosh_classic.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d8/Macintosh_classic.jpg License: CC-BY- SA-3.0 Contributors: ? Original artist: ?
• File:Magnifying_glass2.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/50/Magnifying_glass2.jpg License: GFDL Contributors: Own work Original artist: Heptagon
• File:Main_Oracle_Memory_Areas.png Source: https://upload.wikimedia.org/wikipedia/commons/a/a5/Main_Oracle_Memory_ Areas.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Scifipete
• File:Mainframe_Computer.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/52/Mainframe_Computer.svg License: Public domain Contributors: Own work Original artist: Purnendu Karmakar
• File:Memory_module_DDRAM_20-03-2006.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/ca/Memory_module_ DDRAM_20-03-2006.jpg License: Public domain Contributors: No machine-readable source provided. Own work assumed (based on copyright claims). Original artist: No machine-readable author provided. Cyberdex assumed (based on copyright claims).
• File:Micro_SATA_labeled_pinnout_connector_on_1.8_\char"0022\relax{}_Toshiba_hard_drive.jpg Source: https: //upload.wikimedia.org/wikipedia/commons/8/8b/Micro_SATA_labeled_pinnout_connector_on_1.8_%22_Toshiba_hard_drive.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Fustigate314159
• File:Microchip_rfid_rice.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/c7/Microchip_rfid_rice.jpg License: Public domain Contributors: No machine-readable source provided. Own work assumed (based on copyright claims). Original artist: No machine- readable author provided. Light Warrior assumed (based on copyright claims).
• File:Microsoft_Access_2013_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/3/37/Microsoft_Access_2013_logo. svg License: Public domain Contributors: This file has been extracted from another file: Microsoft Office 2013 logos lineup.svg Original artist: Micrososft
• File:Microsoft_Natural_Ergonomic_Keyboard_4000.png Source: https://upload.wikimedia.org/wikipedia/commons/2/20/ Microsoft_Natural_Ergonomic_Keyboard_4000.png License: CC BY-SA 3.0 Contributors: Own work Original artist: DraugTheWhopper
• File:Microsoft_OneNote_2013_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/9/9e/Microsoft_OneNote_2013_ logo.svg License: Public domain Contributors: This file has been extracted from another file: Microsoft Office 2013 logos lineup.svg Original artist: Microsoft
• File:Microsoft_Word_2013_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/4/4f/Microsoft_Word_2013_logo.svg License: Public domain Contributors: This file has been extracted from another file: Microsoft Office 2013 logos lineup.svg Original artist: Microsoft
• File:Mivar_32LED1_100_Hz.png Source: https://upload.wikimedia.org/wikipedia/commons/d/df/Mivar_32LED1_100_Hz.png Li- cense: CC BY-SA 3.0 Contributors: Own work Original artist: Enzo1
• File:More_Spaghetti,_I_Say_(95916146).jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/14/More_Spaghetti%2C_ I_Say_%2895916146%29.jpg License: CC BY-SA 2.0 Contributors: More Spaghetti, I Say Original artist: Kim Scarborough from Chicago, IL
• File:Morris_Worm.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b6/Morris_Worm.jpg License: CC BY-SA 2.0 Contributors: Museum of Science - Morris Internet Worm Original artist: Go Card USA from Boston, USA
• File:Motherboard.JPG Source: https://upload.wikimedia.org/wikipedia/commons/e/ef/Motherboard.JPG License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Gani01
• File:Mountain_path_pagoda_for_relaxation_and_viewing.JPG Source: https://upload.wikimedia.org/wikipedia/commons/e/ e4/Mountain_path_pagoda_for_relaxation_and_viewing.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: Sonjournermonde
• File:Mp3.svg Source: https://upload.wikimedia.org/wikipedia/commons/e/ea/Mp3.svg License: Public domain Contributors: https://web. archive.org/web/20070307034016/http://www.iis.fraunhofer.de/fhg/Images/logo_mp3_surround_large_tcm97-67934.jpg Original artist: Unknown<a href='//www.wikidata.org/wiki/Q4233718' title='wikidata:Q4233718'><img alt='wikidata:Q4233718' src='https://upload. wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/20px-Wikidata-logo.svg.png' width='20' height='11' srcset='https:// upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/30px-Wikidata-logo.svg.png 1.5x, https://upload.wikimedia. org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/40px-Wikidata-logo.svg.png 2x' data-file-width='1050' data-file-height='590' /></a>
• File:Mr._Potato_Head_and_Friends.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b9/Mr._Potato_Head_and_ Friends.jpg License: CC BY-SA 2.0 Contributors: http://www.flickr.com/photos/imuttoo/441072607/ Original artist: Ian Muttoo
• File:Multi-pass_compiler-it.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/67/Multi-pass_compiler-it.svg License: CC0 Contributors: Own work Original artist: LoStrangolatore
• File:Multimedia.png Source: https://upload.wikimedia.org/wikipedia/commons/2/2e/Multimedia.png License: GPLv3 Contributors: Created by Raul654 using Image:Crystal Clear app aktion.png and Image:Gnome-speakernotes.png Original artist: Raul654
• File:Multimedia_GANTT_Chart.jpg Source: https://upload.wikimedia.org/wikibooks/en/2/22/Multimedia_GANTT_Chart.jpg Li- cense: Public domain Contributors: ? Original artist: ?
• File:Mvdl-logo.png Source: https://upload.wikimedia.org/wikipedia/commons/a/ab/Mvdl-logo.png License: CC BY-SA 3.0 Contributors: MontevideoLibre Original artist: Francisco Gutiérrez
240 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:NCR_Teradata_Worldmark_5100_Unix_Storage.jpeg Source: https://upload.wikimedia.org/wikipedia/commons/a/a3/NCR_ Teradata_Worldmark_5100_Unix_Storage.jpeg License: CC BY 2.0 Contributors: https://www.flickr.com/photos/vax-o-matic/ 13889431087 Original artist: Patrick Finnegan
• File:Nand_flash_structure.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f5/Nand_flash_structure.svg License: CC- BY-SA-3.0 Contributors: en wikipedia Original artist: Cyferz
• File:Napster.png Source: https://upload.wikimedia.org/wikipedia/commons/a/a4/Napster.png License: GPL Contributors: http://www. opendesktop.org/content/show.php?content=72618 Original artist: DBGthekafu
• File:Netflix_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/6/69/Netflix_logo.svg License: Public domain Contrib- utors: Netflix Media Center Original artist: Netflix
• File:New_youtube_logo.png Source: https://upload.wikimedia.org/wikipedia/commons/7/71/New_youtube_logo.png License: Public domain Contributors: YouTube Original artist: ???
• File:No-spam.svg Source: https://upload.wikimedia.org/wikipedia/commons/c/c8/No-spam.svg License: Public domain Contributors: Own work Original artist: Indolences
• File:No_Nuvola_apps_email.png Source: https://upload.wikimedia.org/wikipedia/commons/f/f4/No_Nuvola_apps_email.png License: Public domain Contributors: Own work Original artist: Aqw96
• File:Norton_Logo.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/e8/Norton_Logo.jpg License: Public domain Con- tributors: www.norton.com Original artist: Symantec
• File:Not_facebook_dislike_thumbs_down.png Source: https://upload.wikimedia.org/wikipedia/commons/2/21/Not_facebook_ dislike_thumbs_down.png License: CC BY-SA 3.0 Contributors: File:Facebook like thumb.png Original artist: Kvarki1
• File:Object-Oriented-Programming-Methods-And-Classes-with-Inheritance.png Source: https://upload.wikimedia.org/ wikipedia/commons/3/37/Object-Oriented-Programming-Methods-And-Classes-with-Inheritance.png License: CC BY-SA 3.0 Contributors: Taking a screenshot, then editing using Paint.NET Original artist: Carrot Lord
• File:Octave_like.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/99/Octave_like.jpg License: Attribution Contributors: http://www.enisa.europa.eu/act/rm/cr/risk-management-inventory/files/octave_like.jpg Original artist: ENISA
• File:Office365RetailPack.JPG Source: https://upload.wikimedia.org/wikipedia/commons/e/ea/Office365RetailPack.JPG License: CC0 Contributors: Own work Original artist: Raysonho @ Open Grid Scheduler / Grid Engine
• File:Official_Scratch_Wiki_Logo.png Source: https://upload.wikimedia.org/wikipedia/commons/2/2a/Official_Scratch_Wiki_Logo. png License: CC0 Contributors: http://wiki.scratch.mit.edu/wiki/Scratch_Wiki Original artist: MIT
• File:Old_Philips_television_set,_pic8.JPG Source: https://upload.wikimedia.org/wikipedia/commons/c/c5/Old_Philips_television_ set%2C_pic8.JPG License: CC0 Contributors: Own work Original artist: Alf van Beem
• File:Online_Shop.gif Source: https://upload.wikimedia.org/wikipedia/commons/9/9a/Online_Shop.gif License: CC BY-SA 3.0 Contrib- utors: Own work Original artist: Rexhep-bunjaku
• File:Operating_system_placement.svg Source: https://upload.wikimedia.org/wikipedia/commons/e/e1/Operating_system_placement. svg License: CC BY-SA 3.0 Contributors: Own work Original artist: Golftheman
• File:Osa_device-wireless-router.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/27/Osa_device-wireless-router.svg License: CC BY-SA 3.0 Contributors: http://www.opensecurityarchitecture.org/cms/library/icon-library Original artist: OSA
• File:Overton’{}s_Computer_Lab.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/88/Overton%27s_Computer_Lab. jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Overton2012
• File:OwnerVehicleDataDictionary.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/70/OwnerVehicleDataDictionary. jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: KellyLawless
• File:POLICAM1.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/1c/POLICAM1.jpg License: Public domain Contrib- utors: Own work Original artist: Geezertd
• File:PSU-gold-rear.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4b/PSU-gold-rear.jpg License: Public domain Contributors: Own photograph.
Camera: Kodak DX7590 (5MP 10X)
Lighting: 3 fluorescent lamps, 3 incandescent bulbs, no flash
Original artist: mboverload • File:PSX-Memory-Card.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/ae/PSX-Memory-Card.jpg License: Public
domain Contributors: Own work Original artist: Evan-Amos • File:Paint_shop_pro_shot_1.jpg Source: https://upload.wikimedia.org/wikibooks/en/b/bc/Paint_shop_pro_shot_1.jpg License: Fair use
Contributors: ? Original artist: ? • File:Pair_Programming.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/66/Pair_Programming.jpg License: CC BY-
SA 3.0 Contributors: Own work Original artist: Calqui • File:Pair_programming_1.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/af/Pair_programming_1.jpg License: CC
BY 2.0 Contributors: Ted & Ian Original artist: Lisamarie Babik • File:Panasonic_cf-29.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0d/Panasonic_cf-29.jpg License: Public domain
Contributors: Own photograph Original artist: Ilja Nieuwland • File:Parallel_computer_printer_port.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/fa/Parallel_computer_printer_
port.jpg License: Public domain Contributors: Own work Original artist: Duncan Lithgow
8.2. IMAGES 241
• File:Parc_Asterix_22.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f6/Parc_Asterix_22.jpg License: Public domain Contributors: Own work Original artist: Arnaud 25
• File:PassWord_Strength.png Source: https://upload.wikimedia.org/wikipedia/commons/3/39/PassWord_Strength.png License: Public domain Contributors: Author:User:Gryllida;source:Gmail registration screenshots; Original artist: Gryllida at en.wikipedia
• File:Pennsylvania-Drivers-License-1.gif Source: https://upload.wikimedia.org/wikipedia/commons/0/02/ Pennsylvania-Drivers-License-1.gif License: Public domain Contributors: http://teejaysmith.blogspot.com/2012/06/affairs-of-states.html > -gif Original artist: Unknown<a href='//www.wikidata.org/wiki/Q4233718' title='wikidata:Q4233718'><img alt='wikidata:Q4233718' src='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/20px-Wikidata-logo.svg.png' width='20' height='11' srcset='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/30px-Wikidata-logo.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/40px-Wikidata-logo.svg.png 2x' data-file-width='1050' data-file-height='590' /></a>
• File:PersonalStorageDevices.agr.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/87/PersonalStorageDevices.agr.jpg License: CC-BY-SA-3.0 Contributors: I took this photograph of artifacts in my possession Original artist: --agr 15:53, 1 Apr 2005 (UTC)
• File:Phish.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/76/Phish.jpg License: Public domain Contributors: ? Original artist: ?
• File:Phishing_warning_in_Internet_Explorer_10_by_the_SmartScreen_Filter.png Source: https://upload.wikimedia.org/ wikipedia/commons/1/1a/Phishing_warning_in_Internet_Explorer_10_by_the_SmartScreen_Filter.png License: CC BY-SA 3.0 nl Contributors: Self-made screenshot Original artist: Brent Geuens (software: Microsoft Corporation)
• File:Phone_book.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/ed/Phone_book.jpg License: CC BY 2.0 Contributors: phone_book Original artist: How can I recycle this (http://www.recyclethis.co.uk)
• File:Php_ligne_de_commandes_script_exemple_hdparm.png Source: https://upload.wikimedia.org/wikipedia/commons/f/f9/Php_ ligne_de_commandes_script_exemple_hdparm.png License: CC-BY-SA-3.0 Contributors: Own work Original artist: Scullder
• File:Piracy_cartoon.gif Source: https://upload.wikimedia.org/wikipedia/commons/8/82/Piracy_cartoon.gif License: Public domain Con- tributors: http://static.thepiratebay.org/doodles/cartoonish.gif Original artist: Dyllan Horrocks (spelling based on signature in the image, may be mispelled)
• File:Pivot_Table.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/14/Pivot_Table.jpg License: CC BY-SA 3.0 Contrib- utors: Own work Original artist: Frostbitcanadian
• File:Plage-braille.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4a/Plage-braille.jpg License: CC BY-SA 3.0 Contrib- utors: Own work Original artist: Sebastien.delorme
• File:Plato_ist2_terminal.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/Plato_ist2_terminal.jpg License: CC BY 1.0 Contributors: Own work (Original text: I created this work entirely by myself.) Original artist: Mabu2 (talk)
• File:Ponkan_query.png Source: https://upload.wikimedia.org/wikipedia/commons/7/74/Ponkan_query.png License: MIT Contributors: http://www.masuseki.com/rnote.php?u=be/ponkan.htm Original artist: Mitiya Masuda
• File:Poppit_Spreadsheet.png Source: https://upload.wikimedia.org/wikipedia/commons/f/f1/Poppit_Spreadsheet.png License: CC BY- SA 3.0 Contributors: Own work Original artist: Jeffreycarllloyd
• File:Popular_Social_Networks,_Gavin_Llewellyn,_CC.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f6/Popular_ Social_Networks%2C_Gavin_Llewellyn%2C_CC.jpg License: CC BY 2.0 Contributors: http://www.flickr.com/photos/gavinjllewellyn/ 6235070321/ Original artist: Gavin Llewellyn
• File:Printed_spool_half.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/15/Printed_spool_half.jpg License: CC BY- SA 3.0 Contributors: Own work Original artist: SuperBlobMonster
• File:Privacy.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/85/Privacy.jpg License: CC BY 3.0 us Contributors: Own work Original artist: EFF
• File:Privacy_Policy_«_CubeMe_-_Shanti_Tara_Feuerlein.pdf Source: https://upload.wikimedia.org/wikipedia/commons/c/cb/ Privacy_Policy_%C2%AB_CubeMe_-_Shanti_Tara_Feuerlein.pdf License: CC BY-SA 3.0 Contributors: Own work Original artist: Shanti111
• File:Prog.png Source: https://upload.wikimedia.org/wikipedia/commons/7/7d/Prog.png License: CC BY-SA 3.0 Contributors: http:// www.ccc.uga.edu/summer/programs/comic2.png Original artist: Images courtesy of http://abstrusegoose.com/ under a Creative Commons license.
• File:Programmer_writing_code_with_Unit_Tests.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/59/Programmer_ writing_code_with_Unit_Tests.jpg License: CC BY-SA 4.0 Contributors: Own work Original artist: Joonspoon
• File:Programming-Icon_string_indexing.png Source: https://upload.wikimedia.org/wikibooks/en/2/2d/Programming-Icon_string_ indexing.png License: ? Contributors: ? Original artist: ?
• File:Prototype_sample.png Source: https://upload.wikimedia.org/wikipedia/commons/a/a6/Prototype_sample.png License: Public do- main Contributors: Own work Original artist: Luís Felipe Braga
• File:Proxy_concept_en.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/Proxy_concept_en.svg License: CC0 Con- tributors: Own work Original artist: H2g2bob
• File:Public_key_encryption_keys.png Source: https://upload.wikimedia.org/wikipedia/commons/b/bc/Public_key_encryption_keys. png License: CC BY-SA 3.0 Contributors: Own work Original artist: Johannes Landin
• File:Python.svg Source: https://upload.wikimedia.org/wikipedia/commons/0/0a/Python.svg License: CC BY-SA 3.0 Contributors: http: //tango.freedesktop.org Original artist: The people from the Tango! project.
• File:Python_logo_and_wordmark.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f8/Python_logo_and_wordmark. svg License: GPL Contributors: https://www.python.org/community/logos/ Original artist: www.python.org
• File:Question_mark.png Source: https://upload.wikimedia.org/wikipedia/commons/a/af/Question_mark.png License: Public domain Contributors: ? Original artist: ?
242 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:Question_mark_grey.svg Source: https://upload.wikimedia.org/wikipedia/commons/0/03/Question_mark_grey.svg License: CC0 Contributors: Own work Original artist: Xoser
• File:Qxz-ad106.gif Source: https://upload.wikimedia.org/wikipedia/commons/0/0f/Qxz-ad106.gif License: CC BY 3.0 Contributors: • Images used: (all free images): Image:FlTechMillerBldgCLOSE.jpg, Image:Lovett Hall.jpg, Image:Music Auditorium ASU Tempe
AZ 220398.JPG, Image:TU Eindhoven.jpg, Image:WestSideAmonCarterStadium.jpg, Image:Graduation hat.svg, Image:UNSW YS2004 steamboat squad.jpg Original artist: Jamesontai at English Wikipedia
• File:RA-Putty-security_alert.PNG_ Source: https://upload.wikimedia.org/wikibooks/en/c/c5/RA-Putty-security_alert.PNG License: Fair use Contributors: Oracle Enterprise Linux 6 Original artist: Oracle Corporation, Seth Miller
• File:RA-VBox4-Network_adapter_preferences.PNG Source: https://upload.wikimedia.org/wikibooks/en/0/03/ RA-VBox4-Network_adapter_preferences.PNG License: Fair use Contributors: VirtualBox 4.2.12, Microsoft Windows 7 Original artist: Oracle Corporation, Microsoft Corporation, Seth Miller
• File:RC_banner_ad.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/50/RC_banner_ad.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Voiceabove
• File:RFID-stick.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b9/RFID-stick.jpg License: Public domain Contribu- tors: Own work Original artist: Kriplozoik
• File:Random_vs_sequential_access.svg Source: https://upload.wikimedia.org/wikipedia/commons/a/a7/Random_vs_sequential_ access.svg License: Public domain Contributors: Own work Original artist: Me (User:Intgr)
• File:Realtimeclock_Motherboard_Baby_AT_crop.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/8f/ Realtimeclock_Motherboard_Baby_AT_crop.jpg License: CC BY-SA 2.0 Contributors: Derivative work of a CC-BY-SA 2.0 licensed image Original artist: Zac Luzader
• File:Recordable_CDs.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/e3/Recordable_CDs.jpg License: CC-BY-SA- 3.0 Contributors: ? Original artist: ?
• File:Recycle_mini.png Source: https://upload.wikimedia.org/wikipedia/commons/0/0a/Recycle_mini.png License: CC-BY-SA-3.0 Con- tributors: ? Original artist: ?
• File:Recycling_Computers.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/ac/Recycling_Computers.jpg License: Public domain Contributors: ? Original artist: ?
• File:Refreshable_Braille_display.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/06/Refreshable_Braille_display.jpg License: CC-BY-SA-3.0 Contributors: ? Original artist: ?
• File:Relational_database_terms.svg Source: https://upload.wikimedia.org/wikipedia/commons/7/7c/Relational_database_terms.svg License: Public domain Contributors: Own work Original artist: User:Booyabazooka
• File:Remote_Wipe_Apple_iPhone.png Source: https://upload.wikimedia.org/wikipedia/commons/c/c1/Remote_Wipe_Apple_iPhone. png License: CC BY 2.0 Contributors: http://www.flickr.com/photos/intelfreepress/7705440958/sizes/o/in/photostream/ Original artist: Intel Free Press
• File:Roadmap_to_the_Unicode_SMP.svg Source: https://upload.wikimedia.org/wikipedia/commons/0/00/Roadmap_to_the_ Unicode_SMP.svg License: Public domain Contributors: Self-made using this perl script and information from Unicode. Original artist: Drmccreedy
• File:Room_Thermostat_Vaillant.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/44/Room_Thermostat_Vaillant.jpg License: CC BY 2.0 Contributors: Flickr Original artist: Andy Butkaj
• File:Router_1.jpg Source: https://upload.wikimedia.org/wikipedia/commons/5/5c/Router_1.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Encryptedruler
• File:Router_2.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/75/Router_2.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Encryptedruler
• File:SANvsNAS.svg Source: https://upload.wikimedia.org/wikipedia/commons/0/05/SANvsNAS.svg License: CC BY-SA 2.5 Contribu- tors: Transferred from en.wikipedia to Commons by Andresmihkelson using CommonsHelper. Original artist: The original uploader was Mennis at English Wikipedia
• File:SDLC-Maintenance-Highlighted.png Source: https://upload.wikimedia.org/wikipedia/commons/7/7e/ SDLC-Maintenance-Highlighted.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Dzonatas
• File:SDLC_-_Software_Development_Life_Cycle.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/19/SDLC_-_ Software_Development_Life_Cycle.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Cliffydcw
• File:Sample_Prezi.png Source: https://upload.wikimedia.org/wikipedia/commons/a/ad/Sample_Prezi.png License: CC BY-SA 3.0 Con- tributors: Own work Original artist: Eeneemee
• File:Samsung_Galaxy_Note_series_(blank_screens).jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0a/Samsung_ Galaxy_Note_series_%28blank_screens%29.jpg License: CC BY 2.5 Contributors: Own work Original artist:
• File:Santa_fe.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b4/Santa_fe.jpg License: Public domain Contributors: Own work Original artist: Alegsa
• File:Satellite_dish_1_C-Band.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/7b/Satellite_dish_1_C-Band.jpg Li- cense: CC-BY-SA-3.0 Contributors: Picture taken by en:User:Bogdangiusca Original artist: en:User:Bogdangiusca, german translation Andreas -horn- Hornig
8.2. IMAGES 243
• File:Scaner.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/95/Scaner.jpg License: CC BY-SA 2.5 Contributors: No machine-readable source provided. Own work assumed (based on copyright claims). Original artist: No machine-readable author provided. Mamun2a assumed (based on copyright claims).
• File:Schema_internet.png Source: https://upload.wikimedia.org/wikipedia/commons/7/7e/Schema_internet.png License: Public domain Contributors: Original von Mwka aus http://sina.eetezadi.de/inhalt/referate/internet-client_server-p2p-osi-tcp_ip-dienste?id=6&a_id=3& page=5 http://sina.eetezadi.de Original artist: dbenzhuser
• File:Screen_color_test_GameboyColor_Palette5_Orange_Down-A.png Source: https://upload.wikimedia.org/wikipedia/commons/ f/f5/Screen_color_test_GameboyColor_Palette5_Orange_Down-A.png License: Public domain Contributors: Own work (Original text: self-made) Original artist: Ricardo Cancho Niemietz (talk)
• File:Search_box_vector.PNG Source: https://upload.wikimedia.org/wikipedia/commons/f/f7/Search_box_vector.PNG License: Public domain Contributors: Wikipedia screenshots Original artist: MediaWiki developers
• File:Server-based-network.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/fb/Server-based-network.svg License: LGPL Contributors: derived from the Image:Computer n screen.svg which is under the GNU LGPL Original artist: User:Mauro Bieg
• File:Server-database.svg Source: https://upload.wikimedia.org/wikipedia/commons/4/49/Server-database.svg License: CC BY-SA 3.0 Contributors: Derivative work of File:Drive-harddisk.svg from the public domain Tango icon set Original artist: RRZEicons
• File:Server-web-database.svg Source: https://upload.wikimedia.org/wikipedia/commons/0/03/Server-web-database.svg License: CC BY-SA 3.0 Contributors: Own work Original artist: RRZEicons
• File:Session2.gif Source: https://upload.wikimedia.org/wikipedia/commons/9/99/Session2.gif License: Public domain Contributors: Own work Original artist: Pvnpvn
• File:Shelf_(9123295130).jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/7f/Shelf_%289123295130%29.jpg License: CC BY 2.0 Contributors: DSCN0258 Original artist: Kenta Hayashi
• File:Shinhyong_Eom3.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d2/Shinhyong_Eom3.jpg License: Copyrighted free use Contributors: Competitive Display Technologies” white paper, iMOD Qualcomm MEMS Technologies ((May 2008 Original artist: Qualcomm
• File:Shopping_cart_icon.svg Source: https://upload.wikimedia.org/wikipedia/commons/d/df/Shopping_cart_icon.svg License: Public domain Contributors: Own work Original artist: Jbarta
• File:Shopping_list.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f4/Shopping_list.jpg License: CC BY 2.0 Contribu- tors: http://www.flickr.com/photos/desiitaly/2105224119/ Original artist: the Italian voice
• File:Skype-icon.gif Source: https://upload.wikimedia.org/wikipedia/commons/1/1a/Skype-icon.gif License: Public domain Contributors: http://de.wikipedia.org/wiki/Datei:Skype-icon.svg Original artist: keiner, da kein Werk
• File:Slideshow.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/03/Slideshow.jpg License: CC BY-SA 2.0 Contributors: Welcome to Powerpoint Original artist: Gareth Saunders from Cellardyke, United Kingdom
• File:Small_cdisk_ubt.jpeg Source: https://upload.wikimedia.org/wikipedia/commons/1/18/Small_cdisk_ubt.jpeg License: CC-BY-SA- 3.0 Contributors: Own work Original artist: Tomasz Sienicki [user: tsca, mail: tomasz.sienicki at gmail.com]
• File:Smart-Card-Chip_back.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0d/Smart-Card-Chip_back.jpg License: CC BY-SA 3.0 de Contributors: Self-photographed Original artist: jailbird
• File:Smart_Home_Control_Panel.png Source: https://upload.wikimedia.org/wikipedia/commons/7/76/Smart_Home_Control_Panel. png License: Public domain Contributors: http://core0.staticworld.net/images/article/2014/06/vivint_skycontrolpanel_1-100311233-orig. png Original artist: Unknown<a href='//www.wikidata.org/wiki/Q4233718' title='wikidata:Q4233718'><img alt='wikidata:Q4233718' src='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/20px-Wikidata-logo.svg.png' width='20' height='11' srcset='https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/30px-Wikidata-logo.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/40px-Wikidata-logo.svg.png 2x' data-file-width='1050' data-file-height='590' /></a>
• File:Smart_phone.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/21/Samsung_Galaxy_Note_series_20140614.jpg License: CC BY 2.5 Contributors: Own work Original artist:
• File:Smartmedia_card_closeup.jpg Source: https://upload.wikimedia.org/wikipedia/commons/a/ab/Smartmedia_card_closeup.jpg Li- cense: CC-BY-SA-3.0 Contributors: ? Original artist: ?
• File:SnapchatLogo.png Source: https://upload.wikimedia.org/wikipedia/commons/b/be/SnapchatLogo.png License: Public domain Con- tributors: http://droidsoft.fr/2014/01/02/snapchat-46m-de-numeros-de-telephone-voles/ Original artist: Snapchat, Inc.
• File:SoftwareDevelopmentLifeCycle.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4f/ SoftwareDevelopmentLifeCycle.jpg License: CC BY-SA 3.0 Contributors: Agile Software Development Methods: Review and Analysis Original artist: Abrahamsson, P., Salo, O., Ronkainen, J., & Warsta, J.
• File:Solar_Panel.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/7e/Solar_Panel.jpg License: Public domain Contribu- tors: Own work Original artist: Levan jgarkava
• File:Spotify.svg Source: https://upload.wikimedia.org/wikipedia/commons/a/a0/Spotify.svg License: Public domain Contributors: “Partner Brand Guidelines”, Spotify Original artist: Spotify
• File:Ssl_com_ev_uc_certificate.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/d2/Ssl_com_ev_uc_certificate.jpg Li- cense: CC BY-SA 3.0 Contributors: Screenshot of ssl.com public website’s ssl ev ucc certificate Original artist: Buttysquirrel
• File:Star-schema.png Source: https://upload.wikimedia.org/wikipedia/commons/b/bb/Star-schema.png License: CC BY-SA 3.0 Con- tributors: Own work Original artist: SqlPac
• File:Star_C6000.jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/34/Star_C6000.jpg License: Public domain Contribu- tors: Own work Original artist: Edge bit
• File:Super_80_computer_Logic_board_(reverse).JPG Source: https://upload.wikimedia.org/wikipedia/commons/1/12/Super_80_ computer_Logic_board_%28reverse%29.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: GFHandel
244 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:Surge_suppressor.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/20/Surge_suppressor.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Encryptedruler
• File:Surprised_young_cat.JPG Source: https://upload.wikimedia.org/wikipedia/commons/f/f9/Surprised_young_cat.JPG License: CC BY 3.0 Contributors: Own work Original artist: Watchduck (a.k.a. Tilman Piesk)
• File:Surveillance_cameras.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0c/Surveillance_cameras.jpg License: CC- BY-SA-3.0 Contributors: ? Original artist: ?
• File:Sushiusb.jpg Source: https://upload.wikimedia.org/wikipedia/commons/d/de/Sushiusb.jpg License: CC-BY-SA-3.0 Contributors: Transferred from en.wikipedia to Commons. Original artist: The original uploader was Tokugawapants at English Wikipedia
• File:System-software-update.png Source: https://upload.wikimedia.org/wikipedia/commons/1/11/System-software-update.png Li- cense: GPL Contributors: http://www.opendesktop.org/content/show.php?content=72618 Original artist: DBGthekafu
• File:System_Clock.png Source: https://upload.wikimedia.org/wikipedia/commons/c/c3/System_Clock.png License: Public domain Con- tributors: Transferred from it.wikibooks to Commons. Original artist: Original uploader was Grop at it.wikibooks
• File:TM-database.JPG Source: https://upload.wikimedia.org/wikipedia/commons/7/73/TM-database.JPG License: Public domain Con- tributors: http://yehongmei.narod.ru/TM-database.JPG Original artist: sasha
• File:TVFree-copyright.PNG Source: https://upload.wikimedia.org/wikipedia/commons/f/fe/TVFree-copyright.PNG License: CC-BY- SA-3.0 Contributors: ? Original artist: ?
• File:Tape_Cartridge_Detail.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/0f/Tape_Cartridge_Detail.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Jeran Renz
• File:Teleconference_of_Afghan_Female_Doctors_(5413471901).jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/ef/ Teleconference_of_Afghan_Female_Doctors_%285413471901%29.jpg License: CC BY-SA 2.0 Contributors: Teleconference of Afghan Female Doctors Original artist: Peretz Partensky from San Francisco, USA
• File:Tesco_Tech_Support_Advisor.png Source: https://upload.wikimedia.org/wikipedia/commons/0/02/Tesco_Tech_Support_ Advisor.png License: Public domain Contributors: Geoff Williams Original artist: Geoffdwilliams
• File:Testing_Terminologies.pdf Source: https://upload.wikimedia.org/wikipedia/commons/0/01/Testing_Terminologies.pdf License: CC0 Contributors: www.istqb.in Original artist: Testing services
• File:Texting.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/86/Texting.jpg License: CC BY 3.0 Contributors: Own work Original artist: Alton
• File:Thumbs_up_icon.png Source: https://upload.wikimedia.org/wikipedia/commons/e/e8/Thumbs_up_icon.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Faccialive edited by VolodyA! V Anarhist
• File:Thunderbolt-Connector.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/69/Thunderbolt-Connector.jpg License: CC0 Contributors: Own work Original artist: Heavysilence
• File:Toby_churchill_after_receiving_doctorate1.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/16/Toby_ churchill_after_receiving_doctorate1.jpg License: Public domain Contributors: Own work Original artist: MrArmstrong2
• File:Tor_green_onion.png Source: https://upload.wikimedia.org/wikipedia/commons/6/6e/Tor_green_onion.png License: CC BY-SA 3.0 Contributors: https://www.torproject.org/images/icon-default.jpg . As described at the bottom of https://www.torproject.org/ , it is licensed under a Creative Commons Attribution 3.0 United States License. Original artist: Tor project
• File:Trademark-symbol.png Source: https://upload.wikimedia.org/wikipedia/commons/1/1f/Trademark-symbol.png License: Public domain Contributors: Transferred from nl.wikipedia to Commons. Original artist: The original uploader was Wilinckx at Dutch Wikipedia
• File:Trademark_License_FAQ.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f8/Trademark_License_FAQ.svg Li- cense: Public domain Contributors: Own work Original artist: Heatherawalls
• File:Trademark_Warning_Symbol.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/2f/Trademark_Warning_Symbol. svg License: Public domain Contributors: Self-created, uses a modified icon from File:Battery-caution.svg Original artist: ViperSnake151
• File:Triode-english-text.svg Source: https://upload.wikimedia.org/wikipedia/commons/b/ba/Triode-english-text.svg License: CC BY- SA 3.0 Contributors: Own work Original artist: Svjo
• File:Tux.svg Source: https://upload.wikimedia.org/wikipedia/commons/3/35/Tux.svg License: CC0 Contributors: [1] Original artist: Larry Ewing, Garrett LeSage
• File:Twitter_logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/5/51/Twitter_logo.svg License: Public domain Con- tributors: Transferred from en.wikipedia to Commons by Wcam using CommonsHelper. Original artist: The original uploader was GageSkidmore at English Wikipedia
• File:Typing_computer_screen_reflection.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b9/Typing_computer_ screen_reflection.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Almonroth
• File:U.S._Navy_Gunner’{}s_Mate_1st_Class_Joseph_Hourieh,_background,_provides_a_slide_show_presentation_to_ midshipmen_in_the_small_arms_marksmanship_trainer_at_Recruit_Training_Command_at_Naval_Station_Great_Lakes_ 120810-N-CD297-132.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/4f/U.S._Navy_Gunner%27s_Mate_1st_Class_ Joseph_Hourieh%2C_background%2C_provides_a_slide_show_presentation_to_midshipmen_in_the_small_arms_marksmanship_ trainer_at_Recruit_Training_Command_at_Naval_Station_Great_Lakes_120810-N-CD297-132.jpg License: Public domain Contribu- tors: http://www.defenseimagery.mil/imageRetrieve.action?guid=b2e2536cf95a018e4a97dbaae388f82fea0513e1&t=2 Original artist: MC1 Andre N. McIntyre
• File:US-ASCII_code_chart.png Source: https://upload.wikimedia.org/wikipedia/commons/8/82/US-ASCII_code_chart.png License: Public domain Contributors: http://archive.computerhistory.org/resources/text/GE/GE.TermiNet300.1971.102646207.pdf (document not in link given) Original artist: an unknown officer or employee of the United States Government
• File:USB_Stick.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f1/USB_Stick.jpg License: Public domain Contributors: Own work Original artist: TEL0000
8.2. IMAGES 245
• File:USB_flash_drive_(unbranded).jpg Source: https://upload.wikimedia.org/wikipedia/commons/3/30/USB_flash_drive_ %28unbranded%29.jpg License: CC BY 2.0 Contributors: Flickr: USB flash drive (unbranded) Original artist: Peter Hosey
• File:US_Navy_040605-N-6633C-002_Commander_Naval_Reserve_Force,_Vice_Adm._John_G._Cotton,_is_silhouetted_in_ front_of_a_Powerpoint_slide_mapping_out_the_Naval_Reserve_Force’{}s_future.jpg Source: https://upload.wikimedia.org/ wikipedia/commons/8/88/US_Navy_040605-N-6633C-002_Commander_Naval_Reserve_Force%2C_Vice_Adm._John_G._Cotton% 2C_is_silhouetted_in_front_of_a_Powerpoint_slide_mapping_out_the_Naval_Reserve_Force%27s_future.jpg License: Public domain Contributors: This Image was released by the United States Navy with the ID 040605-N-6633C-002 <a class='external text' href='//commons.wikimedia. org/w/index.php?title=Category:Files_created_by_the_United_States_Navy_with_known_IDs,<span>,&,</span>,filefrom=040605-N- 6633C-002#mw-category-media'>(next)</a>. This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing for more information. Original artist: U.S. Navy photo by Journalist 1st Class Greg Cleghorne
• File:Ubuntu_12.04.png Source: https://upload.wikimedia.org/wikipedia/commons/8/86/Ubuntu_12.04.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Ikonoko123
• File:UmbDotNetContols1.gif Source: https://upload.wikimedia.org/wikibooks/en/a/ac/UmbDotNetContols1.gif License: Cc-by-sa-2.5 Contributors: ? Original artist: ?
• File:United_Airlines_-_N74856_(6907353113).jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/05/United_Airlines_ -_N74856_%286907353113%29.jpg License: CC BY-SA 2.0 Contributors: United Airlines - N74856 Original artist: InSapphoWeTrust from Los Angeles, California, USA
• File:Unix-kernel.svg Source: https://upload.wikimedia.org/wikipedia/commons/4/48/Unix-kernel.svg License: Public domain Contribu- tors: Own work Original artist: Ricordisamoa
• File:Update_Manger.png Source: https://upload.wikimedia.org/wikipedia/commons/7/7e/Update_Manger.png License: GPL Contribu- tors: My computer Original artist: ?
• File:Use_Case_diagram_V1.JPG Source: https://upload.wikimedia.org/wikipedia/commons/5/59/Use_Case_diagram_V1.JPG Li- cense: Public domain Contributors: Own work Original artist: Richard Bruce
• File:VA_EA_Meta-Model_Cell_Details_Enlarged.jpg Source: https://upload.wikimedia.org/wikipedia/commons/b/b1/VA_EA_ Meta-Model_Cell_Details_Enlarged.jpg License: Public domain Contributors: [This diagram is the exclusive work of Albin Martin Zuech of Annapolis Maryland, who placed it in the public domain in 2001. Al Zuech maintains the original Visio Diagram in numerous stages of its development between 2000 and present. Al Zuech was the Director, Enterprise Architecture Service at the Department of Veterans Affairs from 2001 until 2007. He incorporated this diagram within the VA-EA to provide a symbolic representation of the Metamodel that VA used, under his direction, to describe the One-VA Enterprise Architecture and to build an EA Repository without the use of Commercial EA Repository Software. The One-VA EA repository was developed using an object oriented database within the Caliber-RM Software Product. Caliber-RM is intended to be used as a software configuration management tool; not as an EA repository. However this tool permitted defining entities and relationships and for defining properties upon both entities and relationships, which made it sufficient for building an EA repository, considering the technology that was available in early 2003. Mr. Zuech’s motivation in selecting this tool was two-fold: (1) none of the commercial repository tools that were available at that time provided a true Zachman Framework representation of models and relationships; and (2) the available commercial tools were highly proprietary and made it difficult to incorporate best-of-breed tools and representations from other vendors or form open sources. This diagram emphasizes several important interpretations of the Zachman Framework and its adaptation to Information technology In- vestment Management. (1) Progressing through the rows from top to bottom, one can trace-out the System Development Lifecycle (SDLC) which is a de facto standard across the Information Industry; (2) The diagram emphasizes the importance of the often-neglected Zachman Row-Six (the Integrated, Operational Enterprise View). Representations in Mr. Zuech’s interpretation of Zachman row-six consist, largely, of measurable service improvements and cost savings/avoidance that result from the business process and technology innovations that were developed across rows two through five. Row-six provides measured Return on Investment for Individual Projects and, potentially, for the entire investment portfolio. Without row-six the Zachman Framework only identifies sunk-cost – the row-six ROI permits the framework to measure benefits and to be used in a continuous improvement process, capturing best practices and applying them back through row-two. Mr. Zuech lectures on these topics at the Federal Enterprise Architecture Certification Institute (FEAC) in Washington D.C. and may be reached for comment at [email protected] ] Original artist: Albin Martin Zuech, Director, VA Enterprise Architecture Service (Retired)
• File:Video_Camera.JPG Source: https://upload.wikimedia.org/wikipedia/commons/4/41/Video_Camera.JPG License: Public domain Contributors: Own work Original artist: Popperipopp
• File:Video_surveillance_sign.jpg Source: https://upload.wikimedia.org/wikipedia/commons/4/47/Video_surveillance_sign.jpg License: CC-BY-SA-3.0 Contributors: Transferred from en.wikipedia to Commons. Original artist: The original uploader was Quadell at English Wikipedia
• File:Vincent_Bethell_Self_Aware_Placard.png Source: https://upload.wikimedia.org/wikipedia/commons/b/be/Vincent_Bethell_ Self_Aware_Placard.png License: CC BY-SA 3.0 Contributors: Own work Original artist: SRHSP
• File:Visual_Basic_for_Applications_logo_and_wordmark.svg Source: https://upload.wikimedia.org/wikipedia/commons/f/f9/ Visual_Basic_for_Applications_logo_and_wordmark.svg License: Public domain Contributors: http://www.brandsoftheworld.com/ Original artist: Microsoft
• File:Voip_HowItWorks_0203v2.jpg Source: https://upload.wikimedia.org/wikipedia/commons/c/cd/Voip_HowItWorks_0203v2.jpg License: Public domain Contributors: http://www.fcc.gov/voip/images/voip_HowItWorks_0203v2.jpg Original artist: Federal Commu- nications Commission (FCC)
• File:W.gl.Alzamento_de_Pascua.png Source: https://upload.wikimedia.org/wikipedia/commons/3/3a/W.gl.Alzamento_de_Pascua.png License: Public domain Contributors: Own work Original artist: Feel free to use my photos, but please mention me as the author.
• File:WD_disk_with_kensington.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/6d/WD_disk_with_kensington.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Bacon narwhal
246 CHAPTER 8. TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES
• File:WIFI_icon.svg Source: https://upload.wikimedia.org/wikipedia/commons/4/44/WIFI_icon.svg License: CC BY-SA 3.0 Contribu- tors: Own work Original artist: Canopus49
• File:Walden_computer.JPG Source: https://upload.wikimedia.org/wikipedia/commons/3/3f/Walden_computer.JPG License: CC BY- SA 3.0 Contributors: Own work Original artist: Bartmoni
• File:Web-browser-openclipart.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/2c/Web-browser-openclipart.svg Li- cense: CC0 Contributors: OpenClipart Original artist: OpenClipart
• File:Web-page.jpg Source: https://upload.wikimedia.org/wikipedia/commons/0/08/Web-page.jpg License: Public domain Contributors: Own work Original artist: Esalamarun
• File:Web_Design_and_Development.png Source: https://upload.wikimedia.org/wikipedia/commons/3/3b/Web_Design_and_ Development.png License: CC BY-SA 3.0 Contributors: Own work, INCRIdea Indonesia Original artist: Muhammad Rafizeldi (Google+, Blog )
• File:Web_Sites_Graphics.png Source: https://upload.wikimedia.org/wikipedia/commons/4/4d/Web_Sites_Graphics.png License: CC BY-SA 3.0 Contributors: Own work Original artist: GR8DAN
• File:Weebly_logo_2013.png Source: https://upload.wikimedia.org/wikipedia/commons/4/43/Weebly_logo_2013.png License: Public domain Contributors: Weebly.com Original artist: Weebly
• File:Wi-Fi-logodibujado.png Source: https://upload.wikimedia.org/wikipedia/commons/6/63/Wi-Fi-logodibujado.png License: CC BY-SA 3.0 Contributors: Own work Original artist: Estefrosangella
• File:Wikibooks_Compose.JPG Source: https://upload.wikimedia.org/wikibooks/en/e/e9/Wikibooks_Compose.JPG License: Fair use Contributors: Self-Created Image Original artist: Ravichandar Krishnamurthy
• File:Wikibrowse_media_player.png Source: https://upload.wikimedia.org/wikipedia/commons/5/58/Wikibrowse_media_player.png License: Public domain Contributors: w:File:Wikibrowse media player.png Original artist: Dilshan
• File:Wikimedia_Servers-0051_19.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/9d/Wikimedia_Servers-0051_19. jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Helpameout
• File:Wikiversity-logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/9/91/Wikiversity-logo.svg License: CC BY-SA 3.0 Contributors: Snorky (optimized and cleaned up by verdy_p) Original artist: Snorky (optimized and cleaned up by verdy_p)
• File:XO-Beta1-mikemcgregor-4.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/83/XO-Beta1-mikemcgregor-4.jpg License: CC BY 2.5 Contributors: http://wiki.laptop.org/go/Image:B1-mikemcgregor-4.jpg Original artist: Photo credit: “Mike McGre- gor”; upload to OLPC-Wiki: OLPC user “Walter”
• File:Xbox360_scratch.PNG Source: https://upload.wikimedia.org/wikipedia/commons/b/b2/Xbox360_scratch.PNG License: Public do- main Contributors: Own work Original artist: Erin Silversmith
• File:Xhtml.png Source: https://upload.wikimedia.org/wikipedia/commons/2/20/Xhtml.png License: Public domain Contributors: Own work Original artist: Zeroos
• File:YAMAHA_PM5D,_Expomusic_2010.jpg Source: https://upload.wikimedia.org/wikipedia/commons/f/f5/YAMAHA_PM5D% 2C_Expomusic_2010.jpg License: CC BY 2.0 Contributors: Yamaha pm5d Original artist: Tiago Cassol Schvarstzhaupt
• File:_Icon_delete.svg Source: https://upload.wikimedia.org/wikipedia/commons/2/2c/Icon_delete.svg License: CC BY-SA 3.0 Contribu- tors:
• Icon_delete.png Original artist: Leandro Paulino: Ergy
8.3 Content license • Creative Commons Attribution-Share Alike 3.0
- Introduction
- Introduction to Computer Information Systems
- Introduction to Computers
- Hardware
- Software
- Networks and the Internet
- Business on the Web
- Systems
- Computers and Society
- See Also
- External Links
- Computers in Your Life
- Why Learn About Computers?
- Computers at Home
- Computers in Education
- Computers on the Job
- Spectrum of Computers
- Electronic Flight Bags
- Portable Computers
- References
- What is a Computer?
- Data vs. Information
- Computers Then and Now
- Hardware
- Software
- Computer Users and Professionals
- References
- Computers to Fit Every Need
- Phablets
- Embedded Computers
- Mobile Devices
- Personal Computers
- Midrange Servers
- Mainframe Computers
- References
- Computer Networks and the Internet
- The History of the Internet
- From ISP to URL
- Internet Communication
- Searching the Internet
- TCP/IP
- References
- Computers and Society
- Benefits of a Computer-Oriented Society
- Disadvantages of a Computer-Oriented Society
- Differences in Online Communications
- The Anonymity Factor
- Integrity Factor
- References
- Review
- Key Terms
- Review Questions
- References
- Answers
- Hardware
- The System Unit
- Data and Program Representation
- Digital data and numerical data
- Coding systems
- Graphics Data
- Audio Data
- Video Data
- The System Unit - The Motherboard and CPU
- The System Unit - Memory, Buses, Ports
- Memory
- Ports
- Thunderbolt port
- Power supply unit
- Ethernet Cable in Theatre
- How the CPU Works
- How the CPU Works
- Improving the Performance of Your Computer
- Add More Memory and Buy a Larger or Second Hard Drive
- Upgrade To A Solid-State Drive
- Upgrade Your Internet Connection
- System Maintenance
- Future Trends
- Review Definitions
- Review Questions
- Review Answers
- References
- Storage
- Storage System Characteristics
- Floppy Disk
- Storage Media, Storage Technology, and Volatility
- Clusters, Sectors, and Tracks
- Random vs. Sequential
- Storage Devices and Storage Media
- Hard Drives
- Disk Access Time
- Hard drive interface standards
- Optical Discs
- Characteristics
- History
- CDs, DVDs, and BDs
- Flash Memory
- Other Types of Storage Systems
- Remote Storage
- Holographic Storage
- Storage area network
- Network Attached Storage
- NAS vs SAN and Cloud Storage
- Smart Cards
- Large Computer Storage Systems
- Review
- Review Questions
- Glossary
- References
- Input and Output
- Keyboards, Pointing, and Touch Devices
- Specialized Pointing Devices
- Scanners, Readers, Digital Cameras
- Biometric Readers
- Audio Input and Output
- Audio Input
- Audio Output
- Display Devices
- Printers
- Laser printers
- Review
- Review Questions
- Answers
- References
- Software
- System Software
- Systems Software Overview
- Systems Software vs Application Software
- The Operating System
- Multitasking and Multithreading
- Functions of the Operating System
- Operating Systems for Personal Computers
- Buffering and Spooling
- Operating Systems for Mobile Phones
- Utility Programs
- Review
- Review: Key Terms
- Review Questions
- Answer Key for Review Questions
- Review Reference
- References
- Application Software
- Application Software Basics
- Installed vs. Web-based
- Creating Application Software
- Software Ownership
- Software Suites
- Word Processing
- Spreadsheets
- What is a Spreadsheet
- Tables, Graphics, and Templates
- How to use a Spreadsheet
- Database
- Presentation Graphics
- Powerpoint
- Inside Scoop on New Presentation Software
- Graphics and Multimedia
- Review
- Key Terms
- Accessibility Software
- Review Questions
- References
- Networks and the Internet
- Computer Networks
- Networking Applications
- Network Characteristics
- Network Topology
- Network Architecture
- Network Size
- Network Media
- Types of Cables
- Network Architecture & Network Topologies
- Data Transmission Characteristics
- Communications Protocols and Networking Standards
- Networking Hardware
- Review
- Internet
- Evolution of the Internet
- The World Wide Web
- Using the Internet
- Searching the Internet
- Beyond Browsing and Email
- Pros and Cons
- Censorship and Privacy
- Review
- References
- Security
- Unauthorized Access and Control Systems
- Computer Sabotage
- Online Theft and Fraud
- Protecting Against Online Theft and Fraud
- Personal Safety
- Protecting Against Cyberbullying, Cyberstalking, and Other Personal Safety Concerns
- Network and Internet Security Legislation
- Review
- Business on the Web
- Multimedia
- Web-Based Multimedia
- Multimedia Elements
- Multimedia Web Design
- Creating a Web Site using HTML, XML, XHTML, CSSs
- Multimedia Web Development (Scripting, Development Tools, Authoring Software, and Testing)
- References
- Review
- E-Commerce
- What is E-Commerce?
- E-Commerce Business Models
- E-Commerce Web Sites
- Implementing E-Commerce
- Effective E-Commerce Websites
- E-Commerce Sales and Marketing Strategies
- Review
- Review Questions
- References
- Systems
- Information Systems
- What is an Information System?
- Types of Information Systems
- IBM Watson and Cognitive Computing
- System Development
- SDLC - System Development Life Cycle
- System Development Approaches
- Review
- References
- Program Development
- Program Design and Development
- Program Development Life Cycle - Analysis, Design, Coding
- Program Development Life Cycle - Debugging and Testing, Implementation and Maintenance
- Program Development Tools
- Programming Languages
- Key Terms Review
- Review Questions
- Review Answers
- References
- Database
- Database Definition and Examples
- Data Characteristics
- The Data Dictionary
- Data Security and Privacy
- Classification of Databases
- Database Models
- Databases on the Web
- Review
- References
- Computers and Society
- Computer Security
- Hardware Loss or Damage
- Encryption
- Software Piracy
- Electronic Profiling, Privacy Policy and Spam
- Electronic Surveillance
- Software Piracy and Digital Counterfeiting
- Computer Security and Privacy Legislation
- Review
- Key Terms
- Review Questions
- Ethics
- Intellectual Property Rights
- Ethics
- History of Computer Ethics
- Computers and Your Health
- Technology Access
- Environmental Issues
- Review
- Text and image sources, contributors, and licenses
- Text
- Images
- Content license
Introduction to Networking
Charles Severance
Credits
Illustrations: Mauro Toselli
Editorial Support: Sue Blumenberg
Cover Design: Aimee Andrion
The SketchNote illustrations were drawn on an iPad using Paper
by www.fiftythree.com using a dedicated stylus pencil. The illus-
trations were converted from PNG to SVG and EPS vector formats
using www.vectormagic.com. The technical figures for the book
were drawn with OmniGraffle.
Printing History
2015-May-25 Original Printing - CreateSpace
Copyright Details
This book is Copyright Charles R. Severance.
The paper/print version of this book is licensed under a Creative
Commons Attribution-NonCommercial 4.0 International License.
Permission is specifically granted to make copies as necessary
of all or part of the materials in this book as part of a course or
course packet.
http://creativecommons.org/licenses/by-nc/4.0
Electronic copies of this book in EPUB, PDF, and HTML are licensed
under a Creative Commons Attribution 4.0 International License.
http://creativecommons.org/licenses/by/4.0/
If you are interested in translating this book into a language other
than English, please contact me. I am willing to give commercial
print distribution rights for a complete and responsible transla-
tion.
Preface
The goal of this book is to provide a basic understanding of the
technical design and architecture of the Internet. The book is
aimed at all audiences – even those with absolutely no prior tech-
nical experience or math skills. The Internet is an amazingly beau-
tiful design and should be understood by all who use it.
While this book is not about the Network+ or CCNA certifications,
I hope it serves as a way to give students interested in these
certifications a good starting point.
I want to thank Pamela Fox of Khan Academy for coming up with
the idea of an introductory network technology course using open
materials.
I initially developed this material as a single week’s lecture in the
SI502 - Networked Computing course that I taught at the Univer-
sity of Michigan School of Information starting in 2008. I refined
and expanded the material to be three weeks of the Internet His-
tory, Technology, and Security (IHTS) course that I have taught to
over 100,000 students on Coursera starting in 2012. This book
adds further detail to create a standalone text that can be read
for enjoyment or used to support an introductory course that fo-
cuses on the Internet’s architecture.
This book has been particularly fun in that it is a collaboration with
my friends Mauro Toselli (@xlontrax) and Sue Blumenberg. I met
Mauro and Sue in 2012 when they became volunteer Community
Teaching Assistants (CTAs) for my IHTS course on Coursera. Over
the past three years we have become friends and colleagues. It
is a great example of how open education can bring people to-
gether.
There is supporting material for this book at
http://www.net-intro.com/
If you like the book, let us know. Send us a tweet with your
thoughts. You can also send a tweet if you find an error in the
book.
Charles R. Severance (@drchuck)
www.dr-chuck.com
Ann Arbor, MI USA
May 20, 2015
iv
Contents
1 Introduction 1
1.1 Communicating at a Distance . . . . . . . . . . . . . . . . 1
1.2 Computers Communicate Differently . . . . . . . . . . . 4
1.3 Early Wide Area Store-and-Forward Networks . . . . . . 5
1.4 Packets and Routers . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Addressing and Packets . . . . . . . . . . . . . . . . . . . . 7
1.6 Putting It All Together . . . . . . . . . . . . . . . . . . . . . 8
1.7 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.8 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Network Architecture 13
2.1 The Link Layer . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2 The Internetwork Layer (IP) . . . . . . . . . . . . . . . . . 16
2.3 The Transport Layer (TCP) . . . . . . . . . . . . . . . . . . 18
2.4 The Application Layer . . . . . . . . . . . . . . . . . . . . . 20
2.5 Stacking the Layers . . . . . . . . . . . . . . . . . . . . . . 21
2.6 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.7 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3 Link Layer 25
3.1 Sharing the Air . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.2 Courtesy and Coordination . . . . . . . . . . . . . . . . . . 28
3.3 Coordination in Other Link Layers . . . . . . . . . . . . . 29
3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
v
vi CONTENTS
3.5 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.6 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4 Internetworking Layer (IP) 35
4.1 Internet Protocol (IP) Addresses . . . . . . . . . . . . . . . 37
4.2 How Routers Determine the Routes . . . . . . . . . . . . 39
4.3 When Things Get Worse and Better . . . . . . . . . . . . 39
4.4 Determining Your Route . . . . . . . . . . . . . . . . . . . . 41
4.5 Getting an IP Address . . . . . . . . . . . . . . . . . . . . . 45
4.6 A Different Kind of Address Reuse . . . . . . . . . . . . . 47
4.7 Global IP Address Allocation . . . . . . . . . . . . . . . . . 48
4.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.9 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.10Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5 The Domain Name System 57
5.1 Allocating Domain Names . . . . . . . . . . . . . . . . . . 58
5.2 Reading Domain Names . . . . . . . . . . . . . . . . . . . . 59
5.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.4 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.5 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
6 Transport Layer 63
6.1 Packet Headers . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.2 Packet Reassembly and Retransmission . . . . . . . . . 65
6.3 The Transport Layer In Operation . . . . . . . . . . . . . . 67
6.4 Application Clients and Servers . . . . . . . . . . . . . . . 68
6.5 Server Applications and Ports . . . . . . . . . . . . . . . . 68
6.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.7 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.8 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
CONTENTS vii
7 Application Layer 73
7.1 Client and Server Applications . . . . . . . . . . . . . . . 73
7.2 Application Layer Protocols . . . . . . . . . . . . . . . . . . 75
7.3 Exploring the HTTP Protocol . . . . . . . . . . . . . . . . . 76
7.4 The IMAP Protocol for Retrieving Mail . . . . . . . . . . . 80
7.5 Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
7.6 Writing Networked Applications . . . . . . . . . . . . . . . 83
7.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.8 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.9 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
8 Secure Transport Layer 89
8.1 Encrypting and Decrypting Data . . . . . . . . . . . . . . 90
8.2 Two Kinds of Secrets . . . . . . . . . . . . . . . . . . . . . . 91
8.3 Secure Sockets Layer (SSL) . . . . . . . . . . . . . . . . . 92
8.4 Encrypting Web Browser Traffic . . . . . . . . . . . . . . . 93
8.5 Certificates and Certificate Authorities . . . . . . . . . . 94
8.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
8.7 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
8.8 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
9 The OSI Model 101
9.1 Physical (Layer 1) . . . . . . . . . . . . . . . . . . . . . . . . 102
9.2 Data Link (Layer 2) . . . . . . . . . . . . . . . . . . . . . . . 102
9.3 Network (Layer 3) . . . . . . . . . . . . . . . . . . . . . . . . 102
9.4 Transport (Layer 4) . . . . . . . . . . . . . . . . . . . . . . . 103
9.5 Session (Layer 5) . . . . . . . . . . . . . . . . . . . . . . . . 103
9.6 Presentation (Layer 6) . . . . . . . . . . . . . . . . . . . . . 103
9.7 Application (Layer 7) . . . . . . . . . . . . . . . . . . . . . . 103
9.8 Comparing the OSI and TCP/IP Models . . . . . . . . . . 104
9.9 Link Layer (TCP/IP) . . . . . . . . . . . . . . . . . . . . . . . 104
9.10Internetwork Layer (TCP/IP) . . . . . . . . . . . . . . . . . 105
viii CONTENTS
9.11Transport Layer (TCP/IP) . . . . . . . . . . . . . . . . . . . . 105
9.12Application Layer (TCP/IP) . . . . . . . . . . . . . . . . . . 105
9.13Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
9.14Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
9.15Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
10Wrap Up 109
Chapter 1
Introduction
Using the Internet seems pretty easy. We go to a web address
and up comes a page. Or we go to our favorite social site and
see pictures of our friends, families, and pets. But it takes a lot
of complex software and hardware to make the Internet seem so
simple. The design of the technologies that make today’s Inter-
net work started in the 1960s, and there were over 20 years of
research into how to build internetworking technologies before
the first “Internet” was built in the late 1980s by academics in a
project called NSFNet. Since then, the research and development
into improving network technologies has continued as networks
have become far larger and faster and globally distributed with
billions of computers.
In order to better understand how today’s Internet works, we will
take a look at how humans and computers have communicated
using technology over the years.
1.1 Communicating at a Distance
Imagine a group of five people in a room sitting in a circle. As long
as they are courteous and don’t have more than one conversation
at the same time, it’s quite natural for any person to talk to any
other person in the room. They just need to be able to hear each
other and coordinate how to use the shared space in the room.
But what if we put these people in different rooms so they can
no longer see or hear each other? How could pairs of people
communicate with each other then? One way might be to run a
wire between each pair of people with a microphone on one end
and a speaker on the other end. Now everyone could still hear all
1
2 CHAPTER 1. INTRODUCTION
the conversations. They would still need to be courteous to make
sure that there was only one conversation going on at the same
time.
Each person would need four speakers (one for each of the other
people) and enough pieces of wire to connect all the microphones
and speakers. This is a problem with five people and it gets far
worse when there are hundreds or thousands of people.
Using wires, microphones, and speakers is how early telephone
systems from the 1900s allowed people to make phone calls. Be-
cause they could not have separate wires between every pair of
telephones, these systems did not allow all pairs of people to be
connected at the same time. Each person had a single connection
to a human “operator”. The operator would connect two wires to-
gether to allow a pair of people to talk, and then disconnect them
when the conversation was finished.
Figure 1.1: Connecting Using Telephone Operators
The first local telephone systems worked well when a customer’s
home or business was close to the operator’s building and a wire
could be strung directly from the operator’s building to the per-
son’s home.
1.1. COMMUNICATING AT A DISTANCE 3
But what if thousands people who are hundreds of kilometers
apart need to be able to communicate? We can’t run 100-
kilometer wires from each home to a single central office. What
the telephone companies did instead was to have many central
offices and run a few wires between the central offices, then
share connections between central offices. For long distances, a
connection might run through a number of central offices. Before
the advent of fiber optic, long-distance telephone calls were
carried between cities on poles with lots of separate wires. The
number of wires on the poles represented the number of possible
simultaneous long-distance phone calls that could use those
wires.
Figure 1.2: Long-Distance Telephone Poles
Since the cost of the wires went up as the length of the wire
increased, these longer connections between offices were quite
expensive to install and maintain, and they were scarce. So in the
early days of telephones, local calls were generally quite inexpen-
sive. But long-distance calls were more expensive and they were
charged by the minute. This made sense because each minute
you talked on a long-distance call, your use of the long-distance
wires meant no one else could use them. The telephone compa-
nies wanted you to keep your calls short so their long-distance
lines would be available for other customers.
When telephone companies started using fiber optic, more ad-
vanced techniques were used to carry many simultaneous long-
distance conversations on a single fiber. When you look at an old
4 CHAPTER 1. INTRODUCTION
photo and see lots of wires on a single pole, it generally means
they were telephone wires and not used to carry electricity.
1.2 Computers Communicate Differently
When humans talk on the phone, they make a call, talk for a
while, and then hang up. Statistically, most of the time, humans
are not talking on the phone. At least they weren’t before ev-
eryone had smartphones. But computers, including the applica-
tions on your smartphone, communicate differently than humans
do. Sometimes computers send short messages to check if an-
other computer is available. Computers sometimes send medium-
sized information like a single picture or a long email message.
And sometimes computers send a lot of information like a whole
movie or a piece of software to install that might take minutes or
even hours to download. So messages between computers can
be short, medium, or long.
In the earliest days of connecting computers to one another, pairs
of computers were connected with wires. The simplest way to
send data from one computer to another was to line up the out-
going messages in a queue and send the messages one after
another as fast as the computers and the wires could carry the
data. Each message would wait for its turn until the messages
ahead of it were sent, and then it would get its chance to be sent
across the connection.
When the computers were in the same building, the building
owner could run wires to connect them. If the computers were
in the same town, the owners of the computers generally had
to lease wires from the telephone companies to connect their
computers. They often would have the phone company connect
the wires together in their central office so that it was not
necessary for one computer to “dial” the other computer to
send data. These leased lines were convenient for computer
communications because they were “always on”, but they were
also quite expensive because they were used 24 hours a day.
When the computers were even farther away, in different cities,
the leased lines were extended using the longer wires connect-
ing the central offices. Since there were so few wires between
central offices, these long-distance leased lines were quite ex-
pensive and their cost increased dramatically as the length of the
leased line increased. But if you had enough money, you could
lease direct connections between your computers so they could
1.3. EARLY WIDE AREA STORE-AND-FORWARD NETWORKS 5
exchange data. This worked pretty well as long as you were only
using one brand of computers, because each computer company
had their own way of using telephone wires to connect their com-
puters together and send data.
1.3 Early Wide Area Store-and-Forward
Networks
In the 1970s and 1980s, people working at universities around
the world wanted to send each other data and messages using
these computer-to-computer connections. Since the cost for each
connection was so high and increased with distance, computers
generally only had connections to other nearby computers. But
if the computer that you were connected to was connected to
another computer and that computer in turn was connected to
another computer, and so on, you could send a message a long
distance as long as each of the computers along the route of the
message agreed to store and forward your message.
Figure 1.3: Store-and-Forward Networks
Over time, with relatively few connections you could send data
long distances across a patchwork of network connections as long
as you were patient. Along the way, after your message reached
one computer, it would have to wait until its turn came to be
sent to the next computer along the route. A message would
arrive at an intermediate computer, be stored for a while (perhaps
hours, depending on traffic), and then be forwarded one more
connection (or “hop”).
6 CHAPTER 1. INTRODUCTION
Sending entire messages one at a time this way, a message might
take minutes, hours, or even days to arrive at its ultimate desti-
nation, depending on the traffic at each of the hops. But even if
it took a few hours for an email message to find its way from one
part of the country to another, this was still much quicker and
easier than sending a letter or postcard.
1.4 Packets and Routers
The most important innovation that allowed messages to move
more quickly across a multi-hop network was to break each mes-
sage into small fragments and send each fragment individually.
In networking terms, these pieces of messages are called “pack-
ets”. The idea of breaking a message into packets was pioneered
in the 1960s, but it was not widely used until the 1980s because it
required more computing power and more sophisticated network-
ing software.
When messages are broken into packets and each packet is sent
separately, if a short message was sent after a large message
had begun, the short message did not have to wait until the entire
long message was finished. The first packet of the short message
only had to wait for the current packet of the large message to be
finished. The system alternated sending packets from the long
and short messages until after a while the short message was
completely sent and the long message resumed making full use
of the network connection.
Breaking the message into packets also greatly reduced the
amount of storage needed in the intermediate computers be-
cause instead of needing to store an entire message for as long
as a few hours, the intermediate computer only needed to store
a few packets for a few seconds while the packets waited for
their turns on the outbound link.
As networks moved away from the store-and-forward approach,
they started to include special-purpose computers that special-
ized in moving packets. These were initially called “Interface Mes-
sage Processors” or “IMPs” because they acted as the interface
between general-purpose computers and the rest of the network.
Later these computers dedicated to communications were called
“routers” because their purpose was to route the packets they
received towards their ultimate destination.
By building routers that specialized in moving packets across mul-
tiple hops, it became simpler to connect computers from multiple
1.5. ADDRESSING AND PACKETS 7
Figure 1.4: Sending Packets
vendors to the same network. To connect any computer to the
network, now all you needed to do was connect it to one router
and then the rest of the communication details were handled by
the other routers.
When multiple computers at one location were connected to-
gether in a “Local Area Network” (or LAN) using physical wiring,
you would connect a router to the local area network. By sending
data through the router, all the computers on the local area
network could send data across the “Wide Area Network” (or
WAN).
1.5 Addressing and Packets
In the early store-and-forward networks it was important to know
the source and destination computers for every message. Each
computer was given a unique name or number that was called
the “address” of the computer. To send a message to another
computer, you needed to add the source and destination address
to the message before sending the message along its way. By
having a source and destination address in each message, the
computers that stored and forwarded the message would be able
to pick the best path for the message if more than one path was
8 CHAPTER 1. INTRODUCTION
available.
When a long message was split into much smaller packets and
each packet was sent individually, the source and destination ad-
dresses had to be added to each packet, so that routers could
choose the best path to forward each packet of the message. In
addition to the source and destination addresses, it was also nec-
essary to add data to each packet indicating the “offset” or po-
sition of the packet in the overall message so that the receiving
computer could put the packets back together in the right order
to reconstruct the original message.
1.6 Putting It All Together
So when we combine all this together we can understand the ba-
sic operation of today’s Internet. We have specialized computers
called “routers” that know how to route packets along a path from
a source to a destination. Each packet will pass through multiple
routers during its journey from the source computer to the desti-
nation computer.
Even though the packets may be part of a larger message, the
routers forward each packet separately based on its source and
destination addresses. Different packets from the same message
may take different routes from the source to the destination. And
sometimes packets even arrive out of order; a later packet might
arrive before an earlier packet, perhaps because of a data “traffic
jam”. Each packet contains an “offset” from the beginning of the
message so that the destination computer can reassemble the
packets in the correct order to reconstruct the original message.
By creating a network using multiple short hops, the overall cost
of communicating across a large geographical area could be
spread across a large number of connecting groups and individ-
uals. Normally, packets would find the shortest path between
the source and destination, but if a link on that path was an
overloaded or broken, the routers could cooperate and reroute
traffic to take slightly longer paths that would get packets from a
source to a destination as quickly as possible.
The core of the Internet is a set of cooperating routers that move
packets from many sources to many destinations at the same
time. Each computer or local area network is connected to a
router that forwards the traffic from its location to the various des-
tinations on the Internet. A router might handle data from a single
1.7. GLOSSARY 9
Figure 1.5: Connecting Around the World
computer like a smartphone, from several computers in the same
building, or from thousands of computers connected to a univer-
sity campus network. The term “Internet” comes from the idea of
“internetworking”, which captures the idea of connecting many
networks together. Our computers connect to local networks and
the Internet connects the local networks together so all of our
computers can talk to each other.
1.7 Glossary
address: A number that is assigned to a computer so that mes-
sages can be routed to the computer.
hop: A single physical network connection. A packet on the In-
ternet will typically make several “hops” to get from its source
computer to its destination.
LAN: Local Area Network. A network covering an area that is
limited by the ability for an organization to run wires or the power
of a radio transmitter.
leased line: An “always up” connection that an organization
leased from a telephone company or other utility to send data
across longer distances.
10 CHAPTER 1. INTRODUCTION
operator (telephone): A person who works for a telephone com-
pany and helps people make telephone calls.
packet: A limited-size fragment of a large message. Large mes-
sages or files are split into many packets and sent across the
Internet. The typical maximum packet size is between 1000 and
3000 characters.
router: A specialized computer that is designed to receive incom-
ing packets on many links and quickly forward the packets on the
best outbound link to speed the packet to its destination.
store-and-forward network: A network where data is sent
from one computer to another with the message being stored
for relatively long periods of time in an intermediate computer
waiting for an outbound network connection to become available.
WAN: Wide Area Network. A network that covers longer dis-
tances, up to sending data completely around the world. A WAN
is generally constructed using communication links owned and
managed by a number of different organizations.
1.8 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. What did early telephone operators do?
a) Maintained cell phone towers
b) Connected pairs of wires to allow people to talk
c) Installed copper wire between cities
d) Sorted packets as they went to the correct destination
2. What is a leased line?
a) A boundary between leased and owned telephone equip-
ment
b) A connection between a keyboard and monitor
c) A wire that ran from one phone company office to another
d) An “always on” telephone connection
3. How long might a message be stored in an intermediate com-
puter for a store-and-forward network?
1.8. QUESTIONS 11
a) less than a second
b) no more than four seconds
c) less than a minute
d) possibly as long as several hours
4. What is a packet?
a) A technique for wrapping items for shipping
b) A small box used for storage
c) A portion of a larger message that is sent across a network
d) The amount of data that could be stored on an early punched
card
5. Which of these is most like a router?
a) A mail sorting facility
b) A refrigerator
c) A high-speed train
d) An undersea telecommunications cable
6. What was the name given to early network routers?
a) Interfaith Message Processors
b) Internet Motion Perceptrons
c) Instant Message Programs
d) Interface Message Processors
7. In addition to breaking large messages into smaller seg-
ments to be sent, what else was needed to properly route
each message segment?
a) A source and destination address on each message segment
b) An ID and password for each message segment
c) A small battery to maintain the storage for each message
segment
d) A small tracking unit like a GPS to find lost messages
8. Why is it virtually free to send messages around the world
using the Internet?
a) Because governments pay for all the connections
b) Because advertising pays for all the connections
c) Because so many people share all the resources
d) Because it is illegal to charge for long-distance connections
12 CHAPTER 1. INTRODUCTION
Chapter 2
Network Architecture
To engineer and build a system as complex as the Internet, en-
gineers try to break a single challenging problem into a set of
smaller problems that can be solved independently and then put
back together to solve the original large problem. The engineers
who built the first internets broke the overall problem into four
basic subproblems that could be worked on independently by dif-
ferent groups.
Transport
Application
Internetwork
Link
Figure 2.1: The Four-Layer TCP/IP Model
They gave these four areas of engineering the following names:
(1) Link, (2) Internetwork, (3) Transport, and (4) Application. We
visualize these different areas as layers stacked on top of each
other, with the Link layer on the bottom and the Application layer
on the top. The Link layer deals with the wired or wireless con-
nection from your computer to the local area network and the
Application layer is what we as end users interact with. A web
13
14 CHAPTER 2. NETWORK ARCHITECTURE
browser is one example of an application in this Internet architec-
ture.
We informally refer to this model as the “TCP/IP model” in refer-
ence to the Transport Control Protocol (TCP) used to implement
the Transport layer and Internet Protocol (IP) used to implement
the Internetwork layer.
We will take a quick look at each of the layers, starting from the
“bottom” of the stack.
2.1 The Link Layer
The Link layer is responsible for connecting your computer to its
local network and moving the data across a single hop. The
most common Link layer technology today is wireless network-
ing. When you are using a wireless device, the device is only
sending data a limited distance. A smartphone communicates
with a tower that is a few kilometers away. If you are using your
smartphone on a train, it needs to switch to a new tower every
few minutes when the train is moving. A laptop that is connected
to a WiFi network is usually communicating with a base station
within 200 meters. A desktop computer that is connected using
a wired connection is usually using a cable that is 100 meters
long or shorter. Link layer technologies are often shared amongst
multiple computers at the same location.
The Link layer needs to solve two basic problems when dealing
with these shared local area networks. The first problem is how
to encode and send data across the link. If the link is wireless,
engineers must agree on which radio frequencies are to be used
to transmit data and how the digital data is to be encoded in the
radio signal. For wired connections, they must agree on what
voltage to use on the wire and how fast to send the bits across
the wire. For Link layer technologies that use fiber optics, they
must agree on the frequencies of light to be used and how fast to
send the data.
In addition to agreeing on how to send data using a shared
medium such as a wireless network, they also need to agree on
how to cooperate with other computers that might want to send
data at the same time. If all the computers on the network tried
to transmit whenever they had data to send, their messages
would collide. The result would be chaos, and receiving stations
would only receive noise. So we need to find a fair way to allow
each station to wait its turn to use the shared network.
2.1. THE LINK LAYER 15
The idea of breaking a large message into packets and then send-
ing each packet separately makes this sharing easier. If only one
computer wants to send data, it will send its packets one right
after another and move its data across the network as quickly as
it can. But if three computers want to send data at the same time,
each computer will send one packet and then wait while the other
two computers send packets. After each of the other computers
sends a packet, the first computer will send its next packet. This
way the computers are sharing access to the network in a fair
way.
But how does a computer know if other computers want to send
data at the same time? Engineers designed an ingenious method
to solve this problem called “Carrier Sense Multiple Access with
Collision Detection”, or CSMA/CD. It is a long name for a simple
and elegant concept. When your computer wants to send data,
it first listens to see if another computer is already sending data
on the network (Carrier Sense). If no other computer is sending
data, your computer starts sending its data. As your computer is
sending data it also listens to see if it can receive its own data. If
your computer receives its own data, it knows that the channel
is still clear and continues transmitting. But if two computers
started sending at about the same time, the data collides, and
your computer does not receive its own data. When a collision is
detected, both computers stop transmitting, wait a bit, and retry
the transmission. The two computers that collided wait different
lengths of time to retry their transmissions to reduce the chances
of a second collision.
When your computer finishes sending a packet of data, it pauses
to give other computers that have been waiting a chance to send
data. If another computer senses that your computer has stopped
sending data (Carrier Sense) and starts sending its own packet,
your computer will detect the other computer’s use of the net-
work and wait until that computer’s packet is complete before
attempting to send its next packet.
This simple mechanism works well when only one computer
wants to send data. It also works well when many computers
want to send data at the same time. When only one computer is
sending data, that computer can make good use of the shared
network by sending packets one after another, and when many
computers want to use the shared network at the same time,
each computer gets a fair share of the link.
Some link layers, like a cellular connection for a smartphone, a
WiFi connection, or a satellite or cable modem, are shared con-
16 CHAPTER 2. NETWORK ARCHITECTURE
Figure 2.2: Carrier Sense/Collision Detection
nections and need techniques like CSMA/CD to insure fair access
to the many different computers connected to the network. Other
link layers like fiber optic cables and leased lines are generally
not shared and are used for connections between routers. These
non-shared connections are still part of the Link layer.
The engineers working on Link layer technologies focus solving
the issues so computers can transmit data across a single link
that ranges in distance from a few meters to as long as hundreds
of kilometers. But to move data greater distances, we need to
send our packets through multiple routers connected by multiple
link layers. Each time our packet passes through another link
layer from one router to another we call it a “hop”. To send data
halfway around the world, it will pass through about 20 routers,
or make 20 “hops”.
2.2 The Internetwork Layer (IP)
Once your packet destined for the Internet makes it across the
first link, it will be in a router. Your packet has a source address
2.2. THE INTERNETWORK LAYER (IP) 17
and destination address and the router needs to look at the des-
tination address to figure out how to best move your packet to-
wards its destination. With each router handling packets destined
for any of many billions of destination computers, it’s not possible
for every router to know the exact location and best route to ev-
ery possible destination computer. So the router makes its best
guess as to how to get your packet closer to its destination.
Each of the other routers along the way also does its best to get
your packet closer to the destination computer. As your packet
gets closer to its final destination, the routers have a better idea
of exactly where your packet needs to go. When the packet
reaches the last link in its journey, the link layer knows exactly
where to send your packet.
We use a similar approach to route ourselves when going on hol-
iday. A holiday trip also has many hops. Perhaps the first hop is
driving your car or taking a cab or bus to a train station. Then
you take a local train from your small town to a larger city. In the
larger city you take a long-distance train to a large city in another
country. Then you take another local train to the small village
where you will stay for your holiday. When you get off the train,
you take a bus, and when you get off the bus, you walk to your
hotel.
If you were on the train between the two large cities and you
asked the conductor the exact location of your hotel in the small
village, the conductor would not know. The conductor only knows
how to get you closer to your destination, and while you are on
the long-distance train that is all that matters. When you get on
the bus at your destination village, you can ask the bus driver
which stop is closest to your hotel. And when you get off the bus
at the right bus stop, you can probably ask a person on the street
where to find the hotel and get an exact answer.
The further you are from your destination, the less you need to
know the exact details of how to get there. When you are far
away, all you need to know is how to get “closer” to your destina-
tion. Routers on the Internet work the same way. Only the routers
that are closest to the destination computer know the exact path
to that computer. All of the routers in the middle of the journey
work to get your message closer to its destination.
But just like when you are traveling, unexpected problems or de-
lays can come up that require a change in plans as your packets
are sent across the network.
Routers exchange special messages to inform each other about
18 CHAPTER 2. NETWORK ARCHITECTURE
Figure 2.3: A Multi-Step Trip
any kind of traffic delay or network outage so that packets can
be switched from a route that is no longer working to a different
route. The routers that make up the core of the Internet are smart
and adapt quickly to both small and large outages or failures of
network connections. Sometimes a connection slows down be-
cause it is overloaded. Other times a connection is physically bro-
ken when a construction crew mistakenly digs up a buried wire
and cuts it. Sometimes there is a natural disaster like a hurricane
or typhoon that shuts down the routers and links in a large ge-
ographical area. The routers quickly detect these outages and
reroute around them if possible.
But sometimes things go wrong and packets are lost. Dealing with
lost packets is the reason for the next layer in our architecture.
2.3 The Transport Layer (TCP)
The Internetwork layer is both simple and complex. It looks at
a packet’s destination address and finds a path across multiple
network hops to deliver the packet to the destination computer.
2.3. THE TRANSPORT LAYER (TCP) 19
But sometimes these packets get lost or badly delayed. Other
times the packets arrive at their destination out of order because
a later packet found a quicker path through the network than an
earlier packet. Each packet contains the source computer’s ad-
dress, the destination computer’s address, and an offset of where
this packet “fits” relative to the beginning of the message. Know-
ing the offset of each packet from the beginning of the message
and the length of the packet, the destination computer can recon-
struct the original message even if the packets were received out
of order.
As the destination computer reconstructs the message and deliv-
ers it to the receiving application, it periodically sends an acknowl-
edgement back to the source computer indicating how much of
the message it has received and reconstructed. But if the des-
tination computer finds that parts of the reconstructed message
are missing, this probably means that these packets were lost
or badly delayed. After waiting a bit, the destination computer
sends a request to the source computer to resend the data that
seems to be missing.
The sending computer must store a copy of the parts of the orig-
inal message that have been sent until the destination computer
acknowledges successful receipt of the packets. Once the source
computer receives the acknowledgment of successful receipt of
a portion of the message, it can discard the data that has been
acknowledged and send some more data.
The amount of data that the source computer sends before wait-
ing for an acknowledgement is called the “window size”. If the
window size is too small, the data transmission is slowed because
the source computer is always waiting for acknowledgments. If
the source computer sends too much data before waiting for an
acknowledgment, it can unintentionally cause traffic problems by
overloading routers or long-distance communication lines. This
problem is solved by keeping the window size small at the begin-
ning and timing how long it takes to receive the first acknowledge-
ments. If the acknowledgments come back quickly, the source
computer slowly increases the window size and if the acknowl-
edgements come back slowly, the source computer keeps the
window size small so as not to overload the network. Just like at
the Link layer, a little courtesy on the Internet goes a long way
toward ensuring good use of the shared network infrastructure.
This strategy means that when the network has high-speed con-
nections and is lightly loaded the data will be sent quickly, and
if the network is heavily loaded or has slow connections the data
20 CHAPTER 2. NETWORK ARCHITECTURE
will be slowed down to match the limitations of the network con-
nections between the source and destination computers.
2.4 The Application Layer
The Link, Internetwork, and Transport layers work together to
quickly and reliably move data between two computers across
a shared network of networks. With this capability to move data
reliably, the next question is what networked applications will be
built to make use of these network connections.
When the first widely used Internet came into being in the mid-
1980s, the first networked applications allowed users to log in to
remote computers, transfer files between computers, send mail
between computers, and even do real-time text chats between
computers.
In the early 1990s, as the Internet came to more people and com-
puters’ abilities to handle images improved, the World Wide Web
application was developed by scientists at the CERN high-energy
physics facility. The web was focused on reading and editing net-
worked hypertext documents with images. Today the web is the
most common network application in use around the world. But
all the other older Internet applications are still in wide use.
Each application is generally broken into two halves. One half of
the application is called the “server”. It runs on the destination
computer and waits for incoming networking connections. The
other half of the application is called the “client” and runs on the
source computer. When you are browsing the web using software
like Firefox, Chrome, or Internet Explorer, you are running a “web
client” application which is making connections to web servers
and displaying the pages and documents stored on those web
servers. The Uniform Resource Locators (URLs) that your web
browser shows in its address bar are the web servers that your
client is contacting to retrieve documents for you to view.
When we develop the server half and the client half of a net-
worked application, we must also define an “application protocol”
that describes how the two halves of the application will exchange
messages over the network. The protocols used for each applica-
tion are quite different and specialized to meet the needs of the
particular application. Later we will explore some of these Appli-
cation layer protocols.
2.5. STACKING THE LAYERS 21
2.5 Stacking the Layers
We usually show the four different layers (Link, Internetwork,
Transport, and Application) stacked on top of each other with
the Application layer at the top and the Link layer at the bottom.
The reason we show them this way is because each layer makes
use of the layers above and below it to achieve networked
communications.
All four layers run in your computer where you run the client ap-
plication (like a browser), and all four layers also run in the des-
tination computer where the application server is running. You
as the end user interact with the applications that make up the
top layer of the stack, and the bottom layer represents the WiFi,
cellular, or wired connection between your computer and the rest
of the Internet.
The routers that forward your packets from one to another to
move your packets towards their destination have no understand-
ing of either the Transport or Application layers. Routers oper-
ate at the Internetwork and Link layers. The source and destina-
tion addresses at the Internetwork layer are all that is needed for
routers to move your packets across the series of links (hops) to
get them to the destination. The Transport and Application lay-
ers only come into play after the Internetwork layer delivers your
packets to the destination computer.
If you wanted to write your own networked application, you would
likely only talk to the Transport layer and be completely uncon-
cerned about the Internetwork and Link layers. They are essen-
tial to the function of the Transport layer, but as you write your
program, you do not need to be aware of any of the lower-layer
details. The layered network model makes it simpler to write net-
worked applications because so many of the complex details of
moving data from one computer to another can be ignored.
Up next, we will talk about these four layers in more detail.
2.6 Glossary
client: In a networked application, the client application is the
one that requests services or initiates connections.
fiber optic: A data transmission technology that encodes data
using light and sends the light down a very long strand of thin
22 CHAPTER 2. NETWORK ARCHITECTURE
glass or plastic. Fiber optic connections are fast and can cover
very long distances.
offset: The relative position of a packet within an overall mes-
sage or stream of data.
server: In a networked application, the server application is the
one that responds to requests for services or waits for incoming
connections.
window size: The amount of data that the sending computer is
allowed to send before waiting for an acknowledgement.
2.7 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. Why do engineers use a “model” to organize their approach
to solving a large and complex problem?
a) Because it allows them to build something small and test it
in a wind tunnel
b) Because talking about a model delays the actual start of the
hard work
c) Because they can break a problem down into a set of smaller
problems that can be solved independently
d) Because it helps in developing marketing materials
2. Which is the top layer of the network model used by TCP/IP
networks?
a) Application
b) Transport
c) Internetwork
d) Link
3. Which of the layers concerns itself with getting a packet of
data across a single physical connection?
a) Application
b) Transport
c) Internetwork
2.7. QUESTIONS 23
d) Link
4. What does CSMA/CD stand for?
a) Carrier Sense Multiple Access with Collision Detection
b) Collision Sense Media Access with Continuous Direction
c) Correlated Space Media Allocation with Constant Division
d) Constant State Multiple Address Channel Divison
5. What is the goal of the Internetwork layer?
a) Insure that no data is lost while enroute
b) Get a packet of data moved across multiple networks from
its source to its destination
c) Make sure that only logged-in users can use the Internet
d) Insure than WiFi is fairly shared across multiple computers
6. In addition to the data, source, and destination addresses,
what else is needed to make sure that a message can be
reassembled when it reaches its destination?
a) An offset of where the packet belongs relative to the begin-
ning of the message
b) A location to send the data to if the destination computer is
down
c) A compressed and uncompressed version of the data in the
packet
d) The GPS coordinates of the destination computer
7. What is “window size”?
a) The sum of the length and width of a packet
b) The maximum size of a single packet
c) The maximum number of packets that can make up a mes-
sage
d) The maximum amount of data a computer can send before
receiving an acknowledgement
8. In a typical networked client/server application, where does
the client application run?
a) On your laptop, desktop, or mobile computer
24 CHAPTER 2. NETWORK ARCHITECTURE
b) On a wireless access point
c) On the closest router
d) In an undersea fiber optic cable
9. What does URL stand for?
a) Universal Routing Linkage
b) Uniform Retransmission Logic
c) Uniform Resource Locator
d) Unified Recovery List
Chapter 3
Link Layer
The lowest layer of our Internet Architecture is the Link layer. We
call it the “lowest layer” because it is closest to the physical net-
work media. Often the Link layer transmits data using a wire, a
fiber optic cable, or a radio signal. A key element of the Link layer
is that usually data can only be transmitted part of the way from
the source computer to the destination computer. Wired Ether-
net, WiFi, and the cellular phone network are examples of link
layers that can transmit data about a kilometer. Fiber optic ca-
bles, particularly those under the oceans, can transmit data up to
thousands of kilometers. Satellite links can also send data over
long distances.
Transport
Application
Internetwork
Link
Figure 3.1: The Link Layer
Regardless of the distance we can send the data, it is still travel-
ing over a single link, and to reach the ultimate destination com-
25
26 CHAPTER 3. LINK LAYER
puter requires forwarding packets across multiple links. In this
section we will look at how one of the most common link layers
functions in some detail. WiFi is a great way to look at many
issues that must be solved at the link layer.1
3.1 Sharing the Air
When your laptop or phone is using WiFi to connect to the Internet,
it is sending and receiving data with a small, low-powered radio.
The radio in your computer can only send data about 300 meters,
so your computer sends your packets to the router in your home,
which forwards the packets using a link to the rest of the Internet.
Sometimes we call the first router that handles your computer’s
packets the “base station” or “gateway”.
All computers that are close enough to the base station with their
radios turned on receive all of the packets the base station trans-
mits, regardless of which computer the packet is supposed to be
sent to. They also “hear” all the packets sent by every other
nearby computer. So your computer needs a way to to know
which packets to treat as its own and which packets are being
sent to other computers and can be safely ignored.
An interesting side effect of the fact that all the computers within
range can hear all packets is that a rogue computer could also be
listening to and capturing your packets, perhaps getting ahold of
important data like bank account numbers or passwords to online
services. We will come back to the issue of protecting your data
from prying eyes and ears in a later section.
Every WiFi radio in every device that is ever built is given a unique
serial number at the time it is manufactured. This means that
each of the computers using WiFi has its own serial number, and
the radio in the gateway also has a serial number. You can usually
go into a settings screen on your device and look up the serial
number for the WiFi radio in your device. It is generally shown in
the following form:
0f:2a:b3:1f:b3:1a
This is just a representation of a 48-bit serial number for your
WiFi radio. It is also called the “Media Access Control” or “MAC”
1We simplify some of the technical detail in these descriptions to make them
easier to understand.
3.1. SHARING THE AIR 27
address. A MAC address is like a “from” or “to” address on a
postcard. Every packet (radio postcard) sent across the WiFi has
a source and destination address, so all of the computers know
which messages are theirs.
When you turn on your computer and connect to a WiFi network,
your computer needs to figure out which of the MAC addresses
on the WiFi can be used to send packets to the router. When you
move from one physical location to another, your computer will
be talking to different gateways and each of those gateways will
have a different serial number. So when you first connect to a
new WiFi, your computer must discover the MAC address for the
gateway of that particular WiFi.
To do this, your computer sends a special message to a broadcast
address, effectively asking the question, “Who is in charge of this
WiFi?” Since your computer knows it is not the gateway itself,
it sends a broadcast message with its own serial number as the
“from” address and the broadcast address as the “to” address to
ask if there are any gateways present on the WiFi network.
From: 0f:2a:b3:1f:b3:1a
To: ff:ff:ff:ff:ff:ff
Data: Who is the MAC-Gateway
for this network?
If there is a gateway on the network, the gateway sends a mes-
sage containing its serial number back to your computer.
From: 98:2f:4e:78:c1:b4
To: 0f:2a:b3:1f:b3:1a
Data: I am the gateway
Welcome to my network
If there are no replies, your computer waits a few seconds and
then assumes there is no gateway for this network. When there
is no gateway, your computer might show a different WiFi icon or
not show the WiFi icon at all. Sometimes there can be more than
one gateway, but we will ignore that for a while because it is a
little complex and not very common.
Once your computer receives a message with the MAC address
of the gateway, it can use that address to send packets that it
wants the gateway to forward to the Internet. From that point on,
all of your computer’s packets have the actual serial number of
28 CHAPTER 3. LINK LAYER
the destination. You want to use the broadcast address as little as
possible because every computer connected to the WiFi receives
and processes any messages sent to the broadcast address to
make sure the messages were not intended for them.
3.2 Courtesy and Coordination
Because many computers are sharing the same radio frequencies,
it’s important to coordinate how they send data. When there’s a
crowd of people in a room, they can’t all talk at the same time or
everything will be garbled. The same thing happens when multi-
ple WiFi radios transmit at the same time on the same frequency.
So we need some way to coordinate all the radios to make best
use of the shared frequencies. We will look at the basics of tech-
nical approaches to avoiding lost data due to transmission “colli-
sions”.
The first technique is called “Carrier Sense”. The technique is
to first listen for a transmission, and if there is already a trans-
mission in progress, wait until the transmission finishes. It might
seem like you could wait for a long time, but since all messages
are broken into packets, usually your computer only has to wait
for the computer currently sending data to finish a packet, after
which your computer gets its chance to send data.
If your computer’s WiFi radio listens for data and hears silence, it
can begin transmitting. But what if another computer’s WiFi radio
that wants to send a packet listened to and heard the same si-
lence and decided to start transmitting at exactly the same time?
If two or more WiFi radios start transmitting at the same time, all
of the data is corrupted and both packets are lost. So once your
WiFi radio starts sending a packet it is important for it to listen to
make sure it can receive its own data. If it is not receiving the
same thing that it is sending, your WiFi radio assumes that a col-
lision has happened (this is called Collision Detection) and stops
transmitting, since it knows that no data will be received by the
destination WiFi radio.
We humans do a similar thing in a room full of people. When two
people start talking at the same time, they are good at noticing
that another person is talking and quickly stop talking. But the
problem is how to restart the conversation. After a long pause it
is common that both people start talking at the exact same time
again. This can happen over and over and each person says “No,
3.3. COORDINATION IN OTHER LINK LAYERS 29
you” repeatedly to attempt to figure out how to get the conversa-
tion restarted. It can be quite comical at times.
The WiFi radios in two computers that send colliding packets are
able to solve this problem much better than people can solve
the problem. When the WiFi radios detect a collision or garbled
transmission, they compute a random amount of time to wait
before retrying the transmission. The rules for computing the
random wait are set up to make sure the two colliding stations
pick different amounts of time to wait before attempting to re-
transmit the packet.
The formal name for the listen, transmit, listen, and wait and retry
if necessary is called “Carrier Sense Multiple Access with Collision
Detection” or CSMA/CD.
It might sound a little chaotic to just “give it a try” and then “give
it another try” if your transmission collides with another station’s
transmission. But in practice it works well. There is a whole cat-
egory of link layers that use this basic pattern of listen, transmit,
listen, and optionally retry. Wired Ethernet, cellular telephone
data, and even Short Message Service (SMS/Texting) all use this
“try then retry” approach.
3.3 Coordination in Other Link Layers
Sometimes when a link layer has many transmitting stations and
needs to operate at near 100% efficiency for long periods of time,
the design takes a different approach. In this approach, there is a
“token” that indicates when each station is given the opportunity
to transmit data. Stations cannot start a transmission unless they
have the token. Instead of listening for “silence” and jumping in,
they must wait for their turn to come around.
When a station receives the token and has a packet to send, it
sends the packet. Once the packet has been sent, the station
gives up the token and waits until the token comes back to it. If
none of the stations have any data to send, the token is moved
from one computer to the next computer as quickly as possible.
A group of people sitting around a meeting could communicate
without ever interrupting each other by having a small ball that
they pass around in a circle and only allowing the person who has
the ball to speak. When you get the ball and have something to
say you talk for a short period (transmit a packet of words) and
then pass the ball on.
30 CHAPTER 3. LINK LAYER
Figure 3.2: Communicating with a Token
The “try then retry” CSMA/CD approach works very well when
there is no data or when low or moderate levels of data are being
sent. But on a token-style network, if there is no data being sent
and you want to send a packet, you still have to wait for a while
before you receive the token and can start transmitting. When
you finish your packet you have to wait until the token comes
back before you can send the next packet. If you are the only
station that wants to send data, you spend a good bit of time
waiting for the token to come back to you after passing through
all of the other stations.
The token approach is best suited when using a link medium
such as as a satellite link or a undersea fiber optic link where
it might take too long or be too costly to detect a collision. The
CSMA/CD (listen-try) is best suited when the medium is inexpen-
sive, shorter distance, and there are a lot of stations sharing the
medium that only send data in short bursts. So that is why WiFi
(and CSMA/CD) is so effective for providing network access in a
coffee shop, home, or room in a school.
3.4 Summary
So now we have looked at the “lowest” layer in our four-layer
architecture. And we have only taken a simple look at how the
3.5. GLOSSARY 31
Link layer works. There are many other details that must be
designed into a link layer like connection distance, voltage, fre-
quency, speed, and many others.
A key benefit of the layered architecture is that engineers who de-
sign and build Link layer technologies can ignore all of the issues
that are handled by the layers above the Link layer. This allows
them to focus on building the best possible solution to moving
data across a single “hop”. Modern-day link layers like WiFi, satel-
lite, cable modems, Ethernet, and cellular technology are very
well developed. Data moves so quickly and seamlessly that once
we get our connection we rarely have to worry about the Link
layer. It just works.
3.5 Glossary
base station: Another word for the first router that handles your
packets as they are forwarded to the Internet.
broadcast: Sending a packet in a way that all the stations con-
nected to a local area network will receive the packet.
gateway: A router that connects a local area network to a wider
area network such as the Internet. Computers that want to send
data outside the local network must send their packets to the
gateway for forwarding.
MAC Address: An address that is assigned to a piece of network
hardware when the device is manufactured.
token: A technique to allow many computers to share the same
physical media without collisions. Each computer must wait until
it has received the token before it can send data.
3.6 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. When using a WiFi network to talk to the Internet, where
does your computer send its packets?
a) A gateway
b) A satellite
32 CHAPTER 3. LINK LAYER
c) A cell phone tower
d) The Internet Central Office
2. How is the link/physical address for a network device as-
signed?
a) By the cell tower
b) By the Internet Assignment Numbers Authority (IANA)
c) By the manufacturer of the link equipment
d) By the government
3. Which of these is a link address?
a) 0f:2a:b3:1f:b3:1a
b) 192.168.3.14
c) www.khanacademy.com
d) @drchuck
4. How does your computer find the gateway on a WiFi net-
work?
a) It has a gateway address installed by the manufacturer
b) It broadcasts a request for the address of the gateway
c) It repeatedly sends a message to all possible gateway ad-
dresses until it finds one that works
d) The user must enter the gateway address by hand
5. When your computer wants to send data across WiFi, what
is the first thing it must do?
a) Listen to see if other computers are sending data
b) Just start sending the data
c) Send a message to the gateway asking for permission to
transmit
d) Wait until informed that it is your turn to transmit
6. What does a WiFi-connected workstation do when it tries to
send data and senses a collision has happened?
a) Keep sending the message so part of the message makes it
through
3.6. QUESTIONS 33
b) Wait until told by the gateway that the collision is over
c) Immediately restart transmitting the message at the begin-
ning
d) Stop transmitting and wait a random amount of time before
restarting
7. When a station wants to send data across a “token”-style
network, what is the first thing it must do?
a) Listen to see if other computers are sending data
b) Just start sending the data
c) Send a message to the gateway asking for permission to
transmit
d) Wait until informed that it is your turn to transmit
34 CHAPTER 3. LINK LAYER
Chapter 4
Internetworking Layer (IP)
Now that we can move data across a single link, it’s time to fig-
ure out how to move it across the country or around the world.
To send data from your computer to any of a billion destinations,
the data needs to move across multiple hops and across multiple
networks. When you travel from your home to a distant destina-
tion, you might walk from your home to a bus stop, take a train to
the city, take another train to the airport, take a plane to a differ-
ent airport, take a taxi into the city, then take a train to a smaller
town, a bus to an even smaller town, and finally walk from the bus
stop to your hotel. A packet also needs to take multiple forms of
transportation to reach its destination. For a packet taking its
“trip” to another country, the “walk”, “bus”, “train”, and “plane”
can be thought of as different link layers like WiFi, Ethernet, fiber
optic, and satellite.
At each point during the trip, you (or your packet) are being trans-
ported using a shared medium. There might be hundreds of other
people on the same bus, train, or plane, but your trip is different
from that of every other traveller because of the decisions that
you make at the end of each of your “hops”. For instance, when
you arrive at a train station, you might get off one train, then walk
through the station and select a particular outbound train to con-
tinue your journey. Travellers with different starting points and
destinations make a different series of choices. All of the choices
you make during your trip result in you following a series of links
(or hops) along a route that takes you from your starting point to
your destination.
As your packet travels from its starting point to its destination,
35
36 CHAPTER 4. INTERNETWORKING LAYER (IP)
Figure 4.1: Travelling Packets
it also passes through a number of “stations” where a decision
is made as to which output link your packet will be forwarded
on. For packets, we call these places “routers”. Like train sta-
tions, routers have many incoming and outgoing links. Some
links may be fiber optic, others might be satellite, and still others
might be wireless. The job of the router is to make sure packets
move through the router and end up on the correct outbound link
layer. A typical packet passes through from five to 20 routers as
it moves from its source to its destination.
But unlike a train station where you need to look at displays to
figure out the next train you need to take, the router looks at the
destination address to decide which outbound link your packet
needs to take. It is as if a train station employee met every single
person getting off an inbound train, asked them where they were
headed, and escorted them to their next train. If you were a
packet, you would never have to look at another screen with a
list of train departures and tracks!
The router is able to quickly determine the outbound link for your
packet because every single packet is marked with its ultimate
destination address. This is called the Internet Protocol Address,
or IP Address for short. We carefully construct IP addresses to
4.1. INTERNET PROTOCOL (IP) ADDRESSES 37
make the router’s job of forwarding packets as efficient as possi-
ble.
4.1 Internet Protocol (IP) Addresses
In the previous section where we talked about Link layer ad-
dresses, we said that link addresses were assigned when the
hardware was manufactured and stayed the same throughout
the life of a computer. We cannot use link layer addresses to
route packets across multiple networks because there is no rela-
tionship between a link layer address and the location where that
computer is connected to the network. With portable computers
and cell phones moving constantly, the system would need to
track each individual computer as it moved from one location to
another. And with billions of computers on the network, using
the link layer address to make routing decisions would be slow
and inefficient.
Transport
Application
Internetwork
Link
Figure 4.2: The Internetwork Layer
To make this easier, we assign another address to every computer
based on where the computer is connected to the network. There
are two different versions of IP addresses. The old (classic) IPv4
addresses consist of four numbers separated by dots like this, and
look like this:
212.78.1.25
38 CHAPTER 4. INTERNETWORKING LAYER (IP)
Each of the numbers can only be from 0 through 255. We have
so many computers connected to the Internet now that we are
running out of IPv4 addresses to assign to them. IPv6 address are
longer and look like:
2001:0db8:85a3:0042:1000:8a2e:0370:7334
For this section we will focus on the classic IPv4 addresses, but all
of the ideas apply equally to IPv4 and IPv6 addresses.
The most important thing about of IP addresses is that they can
be broken into two parts.1 The first part of the two-piece address
is called the “Network Number”. If we break out an IPv4 address
into two parts, we might find the following:
Network Number: 212.78
Host Identifier: 1.25
The idea is that many computers can be connected via a single
connection to the Internet. An entire college campus, school, or
business could connect using a single network number, or only a
few network numbers. In the example above, 65,536 computers
could be connected to the network using the network number of
“212.78”. Since all of the computers appear to the rest of the
Internet on a single connection, all packets with an IP address of:
212.78.*.*
can be routed to the same location.
By using this approach of a network number and a host identifier,
routers no longer have to keep track of billions of individual com-
puters. Instead, they need to keep track of perhaps a million or
less different network numbers.
So when your packet arrives in a router and the router needs to
decide which outbound link to send your packet to, the router
does not have to look at the entire IP address. It only needs to
look at the first part of the address to determine the best out-
bound link.
1There are many points where an IP address can be broken into “Network
Number” and “Host Identifier” - for this example, we will just split the address
in half.
4.2. HOW ROUTERS DETERMINE THE ROUTES 39
4.2 How Routers Determine the Routes
While the idea of the collapsing many IP addresses into a single
network number greatly reduces the number of individual end-
points that a router must track to properly route packets, each
router still needs a way to learn the path from itself to each of the
network numbers it might encounter.
When a new core router is connected to the Internet, it does not
know all the routes. It may know a few preconfigured routes, but
to build a picture of how to route packets it must discover routes
as it encounters packets. When a router encounters a packet that
it does not already know how to route, it queries the routers that
are its “neighbors”. The neighboring routers that know how to
route the network number send their data back to the request-
ing router. Sometimes the neighboring routers need to ask their
neighbors and so on until the route is actually found and sent
back to the requesting router.
In the simplest case, a new core router can be connected to the
Internet and slowly build a map of network numbers to outbound
links so it can properly route packets based on the IP address for
each incoming packet. We call this mapping of network numbers
to outbound links the “routing table” for a particular router.
When the Internet is running normally, each router has a rela-
tively complete routing table and rarely encounters a new net-
work number. Once a router figures out the route to a new net-
work number the first time it sees a packet destined for that net-
work number, it does not need to rediscover the route for the
network number unless something changes or goes wrong. This
means that the router does a lookup on the first packet, but then
it could route the next billion packets to that network number just
by using the information it already has in its routing tables.
4.3 When Things Get Worse and Better
Sometimes the network has problems and a router must find a
way to route data around the problems. A common problem is
that one of the outbound links fails. Perhaps someone tripped
over a wire and unplugged a fiber optic cable. At this point, the
router has a bunch of network numbers that it wants to route
out on a link that has failed. The recovery when a router loses
an outbound link is surprisingly simple. The router discards all
40 CHAPTER 4. INTERNETWORKING LAYER (IP)
of the entries in its routing table that were being routed on that
link. Then as more packets arrive for those network numbers, the
router goes through the route discovery process again, this time
asking all the neighboring routers except the ones that can no
longer be contacted due to the broken link.
Figure 4.3: Dynamic Routing
Packets are routed more slowly for a while as routing tables are re-
built that reflect the new network configuration, but after a while
things are humming along nicely.
This is why it is important for there to always be at least two inde-
pendent paths from a source network to a destination network in
the core of the network. If there are always at least two possible
independent routes, we say that a network is a “two-connected
network”. A two-connected network can recover from any single
link outage. In places where there are a lot of network connec-
tions, like the east coast of the United States, the network could
lose many links without ever becoming completely disconnected.
But when you are at your home or school and have only one con-
nection, if that connection goes down you are disconnected com-
pletely.
At some point the broken link is repaired or a new link is brought
up, and the router wants to make best use of the new links. The
4.4. DETERMINING YOUR ROUTE 41
router is always interested in improving its routing tables, and
looks for opportunities to improve its routing tables in its spare
time. When there is a lull in communication, a router will ask a
neighboring router for all or part of its routing table. The router
looks through the neighbor’s tables and if it looks like the other
router has a better route to a particular network number, it up-
dates its network table to forward packets for that network num-
ber through the link to the router that has a better route.
With these approaches to outages and the exchange of routing
table information, routers can quickly react to network outages
and reroute packets from links that are down or slow to links that
are up and/or faster. All the while, each router is talking to its
neighboring routers to find ways to improve its own routing ta-
ble. Even though there is no central source of the “best route”
from any source to any destination, the routers are good at know-
ing the fastest path from a source to a destination nearly all the
time. Routers are also good at detecting and dynamically routing
packets around links that are slow or temporarily overloaded.
One of the side effects of the way routers discover the structure
of the network is that the route your packets take from the source
to the destination can change over time. You can even send one
packet immediately followed by another packet and because of
how the packets are routed, the second packet might arrive at
the destination before the first packet. We don’t ask the IP layer
to worry about the order of the packets; it already has enough to
worry about.
We pour our packets with source and destination IP addresses into
the Internet much like we would send out a bunch of letters in the
mail at the post office. The packets each find their way though
the system and arrive at their destinations.
4.4 Determining Your Route
There is no place in the Internet that knows in advance the route
your packets will take from your computer to a particular destina-
tion. Even the routers that participate in forwarding your packets
across the Internet do not know the entire route your packet will
take. They only know which link to send your packets to so they
will get closer to their final destination.
But it turns out that most computers have a network diagnostic
tool called “traceroute” (or “tracert”, depending on the operating
42 CHAPTER 4. INTERNETWORKING LAYER (IP)
system) that allows you to trace the route between your com-
puter and a destination computer. Given that the route between
any two computers can change from one packet to another, when
we “trace” a route, it is only a “pretty good guess” as to the actual
route packets will take.
The traceroute command does not actually “trace” your packet
at all. It takes advantage of a feature in the IP network protocol
that was designed to avoid packets becoming “trapped” in the
network and never reaching their destination. Before we take a
look at traceroute, let’s take a quick look at how a packet might
get trapped in the network forever and how the IP protocol solves
that problem.
Remember that the information in any single router is imperfect
and is only an approximation of the best outbound link for a par-
ticular network number, and each router has no way of knowing
what any other router will do. But what if we had three routers
with routing table entries that formed an endless loop?
141.21.*.* 141.21.*.*
141.21.*.* 141.21.*.*
141.21.*.* 141.21.*.*
141.21.*.* 141.21.*.*
Figure 4.4: Routing Vortex
Each of the routers thinks it knows the best outbound link for IP
addresses that start with “212.78”. But somehow the routers are
a little confused and their routing tables form a loop. If a packet
with a prefix of “212.78” found its way into one of these routers,
it would be routed around a circle of three links forever. There
is no way out. As more packets arrived with the same prefix,
they would just be added to the “infinite packet vortex”. Pretty
soon the links would be full of traffic going round and round, the
routers would fill up with packets waiting to be sent, and all three
routers would crash. This problem is worse than having someone
4.4. DETERMINING YOUR ROUTE 43
trip over a fiber optic cable, since it can cause several routers to
crash.
To solve this problem, the Internet Protocol designers added a
number to each packet that is called the Time To Live (TTL). This
number starts out with a value of about 30. Each time an IP
packet is forwarded down a link, the router subtracts 1 from the
TTL value. So if the packet takes 15 hops to cross the Internet, it
will emerge on the far end with a TTL of 15.
But now let’s look at how the TTL functions when there is a routing
loop (or “packet vortex”) for a particular network number. Since
the packet keeps getting forwarded around the loop, eventually
the TTL reaches zero. And when the TTL reaches zero, the router
assumes that something is wrong and throws the packet away.
This approach ensures that routing loops do not bring whole areas
of the network down.
So that is a pretty cool bit of network protocol engineering. To
detect and recover from routing loops, we just put a number in,
subtract 1 from that number on each link, and when the number
goes to zero throw the packet away.
It also turns out that when the router throws a packet away, it
usually sends back a courtesy notification, something like, “Sorry
I had to throw your packet away.” The message includes the IP
address of the router that threw the packet away.
Network loops are actually pretty rare, but we can use this notifi-
cation that a packet was dropped to map the approximate route a
packet takes through the network. The traceroute program sends
packets in a tricky manner to get the routers that your packets
pass through to send it back notifications. First, traceroute sends
a packet with a TTL of 1. That packet gets to the first router and
is discarded and your computer gets a notification from the first
router. Then traceroute sends a packet with a TTL of 2. That
packet makes it through the first router and is dropped by the
second router, which sends you back a note about the discarded
packet. Then traceroute sends a packet with a TTL of 3, and con-
tinues to increase the TTL until the packet makes it all the way to
its destination.
With this approach, traceroute builds up an approximate path that
your packets are taking across the network.
It took 14 hops to get from Ann Arbor, Michigan to Palo Alto, Cal-
ifornia. The packets passed through Kansas, Texas, Los Angeles,
and Oakland. This might not be the best route between the two
cities if you were driving a car or taking a train, but on that day
44 CHAPTER 4. INTERNETWORKING LAYER (IP)
traceroute www.stanford.edu
traceroute to www5.stanford.edu (171.67.20.37), 64 hops max, 40 byte packets
1 141.211.203.252 (141.211.203.252) 1.390 ms 0.534 ms 0.490 ms
2 v-bin-seb.r-bin-seb.umnet.umich.edu (192.122.183.61) 0.591 ms 0.558 ms 0.570 ms
3 v-bin-seb-i2-aa.merit-aa2.umnet.umich.edu (192.12.80.33) 6.610 ms 6.545 ms 6.654 ms
4 192.122.183.30 (192.122.183.30) 7.919 ms 7.209 ms 7.122 ms
5 so-4-3-0.0.rtr.kans.net.internet2.edu (64.57.28.36) 17.672 ms 17.836 ms 17.673 ms
6 so-0-1-0.0.rtr.hous.net.internet2.edu (64.57.28.57) 31.800 ms 41.967 ms 31.787 ms
7 so-3-0-0.0.rtr.losa.net.internet2.edu (64.57.28.44) 63.478 ms 63.704 ms 63.710 ms
8 hpr-lax-hpr--i2-newnet.cenic.net (137.164.26.132) 63.093 ms 63.026 ms 63.384 ms
9 svl-hpr--lax-hpr-10ge.cenic.net (137.164.25.13) 71.242 ms 71.542 ms 76.282 ms
10 oak-hpr--svl-hpr-10ge.cenic.net (137.164.25.9) 72.744 ms 72.243 ms 72.556 ms
11 hpr-stan-ge--oak-hpr.cenic.net (137.164.27.158) 73.763 ms 73.396 ms 73.665 ms
12 bbra-rtr.Stanford.EDU (171.64.1.134) 73.577 ms 73.682 ms 73.492 ms
13 * * *
14 www5.Stanford.EDU (171.67.20.37) 77.317 ms 77.128 ms 77.648 ms
Figure 4.5: Traceroute from Michigan to Stanford
for packets between the two cities this was the best route on the
Internet.
Figure 4.6: Notifications of Dropped Packets
You can also see how long it took the packets to make it from the
source to each router, and then from the source to the destination.
A millisecond (ms) is a 1/1000 of a second. So 77.317 ms is just
under a tenth of a second. This network is pretty fast.
Sometimes a traceroute can take a little while, up to a minute or
two. Not all routers will give you the “I discarded your packet”
4.5. GETTING AN IP ADDRESS 45
message. In the example above, the router at hop 13 threw our
packet away without saying “I am sorry”. Traceroute waits for the
message and after a few seconds just gives up and increases the
TTL value so it gets past the rude router.
If you run a traceroute for a connection that includes an undersea
cable, you can see how fast data moves under the sea. Here
is a traceroute between the University of Michigan and Peking
University in China.
$ traceroute www.pku.edu.cn
traceroute to www.pku.edu.cn (162.105.129.104), 64 hops max, 40 byte packets
1 141.211.203.252 (141.211.203.252) 1.228 ms 0.584 ms 0.592 ms
2 v-bin-seb.r-bin-seb.umnet.umich.edu (192.122.183.61) 0.604 ms 0.565 ms 0.466 ms
3 v-bin-seb-i2-aa.merit-aa2.umnet.umich.edu (192.12.80.33) 7.511 ms 6.641 ms 6.588 ms
4 192.122.183.30 (192.122.183.30) 12.078 ms 6.989 ms 7.619 ms
5 192.31.99.133 (192.31.99.133) 7.666 ms 8.953 ms 17.861 ms
6 192.31.99.170 (192.31.99.170) 59.275 ms 59.273 ms 59.108 ms
7 134.75.108.209 (134.75.108.209) 173.614 ms 173.552 ms 173.333 ms
8 134.75.107.10 (134.75.107.10) 256.760 ms 134.75.107.18 (134.75.107.18) 256.574 ms
9 202.112.53.17 (202.112.53.17) 256.761 ms 256.801 ms 256.688 ms
10 202.112.61.157 (202.112.61.157) 257.416 ms 257.960 ms 257.747 ms
11 202.112.53.194 (202.112.53.194) 256.827 ms 257.068 ms 256.962 ms
12 202.112.41.202 (202.112.41.202) 256.800 ms 257.053 ms 256.933 ms
Figure 4.7: Traceroute from Michigan to Peking University
You can see when the packet is encountering a long undersea
cable in steps seven and eight. The time goes from less than
1/10 of a second to nearly 1/4 of a second. Even though 1/4 of a
second is slower than 1/10 a second, it is pretty impressive when
you consider that the packet is going nearly all of the way around
the world in that 1/4 second.
The core of our IP network is remarkable. Most of the time we
don’t really care how hard the routers are working to make sure
our packets move quickly from our computer to the various des-
tinations around the world. Next we will move from looking at
how the core of the network functions to how IP addresses are
managed at the edges.
4.5 Getting an IP Address
Increasingly, computers are portable or mobile. We just pointed
out how important it was for the IP layer to track large groups
of computers using network numbers instead of tracking every
single computer individually. But since these network numbers
indicate a particular physical connection to the network, when
we move a computer from one location to another, it will need a
new IP address. Remember that the link layer address is set when
46 CHAPTER 4. INTERNETWORKING LAYER (IP)
a computer is manufactured and never changes throughout the
life of the computer. If you close your laptop in one coffee shop
and reopen it using your home WiFi, your computer will need a
different IP address.
This ability for your computer to get a different IP address when
it is moved from one network to another uses a protocol called
“Dynamic Host Configuration Protocol” (or DHCP for short). DHCP
is pretty simple. Going back to the Link layer section, recall the
first thing your computer does at the link level is ask “Is there
a base station on this network?” by sending a message to a
special broadcast address. Once your computer is successfully
connected at the link layer through that base station, it sends an-
other broadcast message, this time asking “Is there a gateway
connected to this network that can get me to the Internet? If
there is, tell me your IP address and tell me what IP address I
should use on this network”.
When the gateway router replies, your computer is given a tem-
porary IP address to use on that network (for instance, while you
are at the coffee shop). After the router has not heard from your
computer for a while, it decides you are gone and loans the IP
address to another computer.
If this process of reusing a loaned IP address goes wrong, two
computers end up on the same network with the same IP address.
Perhaps you have seen a message on your computer to the effect
of, “Another computer is using 192.168.0.5, we have stopped us-
ing this address”. Your computer sees another computer with a
link address other than its own using the IP address that your
computer thinks is assigned to it.
But most of the time this dynamic IP address assignment (DHCP)
works perfectly. You open your laptop and in a few seconds you
are connected and can use the Internet. Then you close your
laptop and go to a different location and are given a different IP
address to use at that location.
In some operating systems, when a computer connects to a net-
work, issues a DHCP request, and receives no answer, it decides
to assign itself an IP address anyway. Often these self-assigned
addresses start with “169. . . .”. When your computer has one of
these self-assigned IP addresses, it thinks it is connected to a net-
work and has an IP address, but without a gateway, it has no
possibility of getting packets routed across the local network and
onto the Internet. The best that can be done is that a few com-
puters can connect to a local network, find each other, and play
4.6. A DIFFERENT KIND OF ADDRESS REUSE 47
Figure 4.8: Getting an IP Address via DHCP
a networked game. There is not much else that can be done with
these self-assigned IP addresses.
4.6 A Different Kind of Address Reuse
If you know how to find the IP address on your laptop, you can do
a little experiment and look at the different IP addresses you get
at different locations. If you made a list of the different addresses
you received at the different locations, you might find that many
of the locations give out addresses with a prefix of “192.168.”.
This seems to be a violation of the rule that the network number
(IP address prefix) is tied to the place where the computer is con-
nected to the Internet, but a different rule applies to addresses
that start with “192.168.” (The prefix “10.” is also special).
Addresses that start with “192.168.” are called “non-routable”
addresses. This means that they will never be used as real ad-
dresses that will route data across the core of the network. They
can be used within a single local network, but not used on the
global network.
So then how is it that your computer gets an address like
“192.168.0.5” on your home network and it works perfectly
well on the overall Internet? This is because your home
48 CHAPTER 4. INTERNETWORKING LAYER (IP)
router/gateway/base station is doing something we call “Network
Address Translation”, or “NAT”. The gateway has a single routable
IP address that it is sharing across multiple workstations that are
connected to the gateway. Your computer uses its non-routable
address like “192.168.0.5” to send its packets, but as the packets
move across the gateway, the gateway replaces the address
with its actual routable address. When packets come back to
your workstation, the router puts your workstation’s non-routable
address back into the returning packets.
This approach allows us to conserve the real routable addresses
and use the same non-routable addresses over and over for work-
stations that move from one network to another.
4.7 Global IP Address Allocation
If you wanted to connect the network for a new organization
to the Internet you would need to contact an Internet Service
Provider and make a connection. Your ISP would give you a range
of IP addresses (i.e., one or more network numbers) that you
could allocate to the computers attached to your network. The
ISP assigns you network numbers by giving you a portion of the
network numbers they received from a higher-level Internet Ser-
vice Provider.
At the top level of IP address allocations are five Regional Internet
Registries (RIRs). Each of the five registries allocates IP addresses
for a major geographic area. Between the five registries, every
location in the world can be allocated a network number. The
five registries are North America (ARIN), South and Central Amer-
ica (LACNIC), Europe (RIPE NCC), Asia-Pacific (APNIC) and Africa
(AFRNIC).
When the classic IPv4 addresses like “212.78.1.25” were in-
vented, only a few thousand computers were connected to the
Internet. We never imagined then that someday we would have
a billion computers on the Internet. But today with the expansion
of the Internet and the “Internet of things” where smart cars,
refrigerators, thermostats, and even lights will need IP addresses,
we need to connect far more than a billion computers to the
Internet. To make it possible to connect all these new computers
to the Internet, engineers have designed a a new generation of
the Internet Protocol called “IPv6”. The 128-bit IPv6 addresses
are much longer than the 32-bit IPv4 addresses.
4.8. SUMMARY 49
The Regional Internet Registries (RIRs) are leading the transition
from IPv4 to IPv6. The transition from IPv4 to IPv6 will take many
years. During that time, both IPv4 and IPv6 must work seamlessly
together.
4.8 Summary
The Internetworking Protocol layer extends our network from a
single hop (Link layer) to a series of hops that result in packets
quickly and efficiently being routed from your computer to a des-
tination IP address and back to your computer. The IP layer is
designed to react and route around network outages and main-
tain near-ideal routing paths for packets moving between billions
of computers without any kind of central routing clearinghouse.
Each router learns its position within the overall network, and by
cooperating with its neighboring routers helps move packets ef-
fectively across the Internet.
The IP layer is not 100% reliable. Packets can be lost due to mo-
mentary outages or because the network is momentarily “con-
fused” about the path that a packet needs to take across the
network. Packets that your system sends later can find a quicker
route through the network and arrive before packets that your
system sent earlier.
It might seem tempting to design the IP layer so that it never loses
packets and insures that packets arrive in order, but this would
make it nearly impossible for the IP layer to handle the extreme
complexities involved in connecting so many systems.
So instead of asking too much of the IP layer, we leave the prob-
lem of packet loss and packets that arrive out of order to our next
layer up, the Transport layer.
4.9 Glossary
core router: A router that is forwarding traffic within the core of
the Internet.
DHCP: Dynamic Host Configuration Protocol. DHCP is how a
portable computer gets an IP address when it is moved to a new
location.
50 CHAPTER 4. INTERNETWORKING LAYER (IP)
edge router: A router which provides a connection between a
local network and the Internet. Equivalent to “gateway”.
Host Identifier: The portion of an IP address that is used to
identify a computer within a local area network.
IP Address: A globally assigned address that is assigned to a
computer so that it can communicate with other computers that
have IP addresses and are connected to the Internet. To simplify
routing in the core of the Internet IP addresses are broken into
Network Numbers and Host Identifiers. An example IP address
might be “212.78.1.25”.
NAT: Network Address Translation. This technique allows a single
global IP address to be shared by many computers on a single
local area network.
Network Number: The portion of an IP address that is used to
identify which local network the computer is connected to.
packet vortex: An error situation where a packet gets into an
infinite loop because of errors in routing tables.
RIR: Regional Internet Registry. The five RIRs roughly correspond
to the continents of the world and allocate IP address for the ma-
jor geographical areas of the world.
routing tables: Information maintained by each router that
keeps track of which outbound link should be used for each
network number.
Time To Live (TTL): A number that is stored in every packet
that is reduced by one as the packet passes through each router.
When the TTL reaches zero, the packet is discarded.
traceroute: A command that is available on many Linux/UNIX
systems that attempts to map the path taken by a packet as it
moves from its source to its destination. May be called “tracert”
on Windows systems.
two-connected network: A situation where there is at least two
possible paths between any pair of nodes in a network. A two-
connected network can lose any single link without losing overall
connectivity.
4.10 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
4.10. QUESTIONS 51
1. What is the goal of the Internetworking layer?
a) Move packets across multiple hops from a source to destina-
tion computer
b) Move packets across a single physical connection
c) Deal with web server failover
d) Deal with encryption of sensitive data
2. How many different physical links does a typical packet cross
from its source to its destination on the Internet?
a) 1
b) 4
c) 15
d) 255
3. Which of these is an IP address?
a) 0f:2a:b3:1f:b3:1a
b) 192.168.3.14
c) www.khanacademy.com
d) @drchuck
4. Why is it necessary to move from IPv4 to IPv6?
a) Because IPv6 has smaller routing tables
b) Because IPv6 reduces the number of hops a packet must go
across
c) Because we are running out of IPv4 addresses
d) Because IPv6 addresses are chosen by network hardware
manufacturers
5. What is a network number?
a) A group of IP addresses with the same prefix
b) The GPS coordinates of a particular LAN
c) The number of hops it takes for a packet to cross the network
d) The overall delay packets experience crossing the network
6. How many computers can have addresses within network
number “218.78”?
52 CHAPTER 4. INTERNETWORKING LAYER (IP)
a) 650
b) 6500
c) 65000
d) 650000
7. How do routers determine the path taken by a packet across
the Internet?
a) The routes are controlled by the IRG (Internet Routing Group)
b) Each router looks at a packet and forwards it based on its
best guess as to the correct outbound link
c) Each router sends all packets on every outbound link (flood-
ing algorithm)
d) Each router holds on to a packet until a packet comes in from
the destination computer
8. What is a routing table?
a) A list of IP addresses mapped to link addresses
b) A list of IP addresses mapped to GPS coordinates
c) A list of network numbers mapped to GPS coordinates
d) A list of network numbers mapped to outbound links from
the router
9. How does a newly connected router fill its routing tables?
a) By consulting the IANA (Internet Assigned Numbers Author-
ity)
b) By downloading the routing RFC (Request for Comments)
c) By contacting the Internet Engineering Task Force (IETF)
d) By asking neighboring routers how they route packets
10. What does a router do when a physical link goes down?
a) Throws away all of the routing table entries for that link
b) Consults the Internet Map (IMAP) service
c) Does a Domain Name (DNS) looking for the IP address
d) Sends all the packets for that link back to the source com-
puter
11. Why is it good to have at least a “two-connected” network?
4.10. QUESTIONS 53
a) Because routing tables are much smaller
b) Because it removes the need for network numbers
c) Because it supports more IPv4 addresses
d) Because it continues to function even when a single link
goes down
12. Do all packets from a message take the same route across
the Internet?
a) Yes
b) No
13. How do routers discover new routes and improve their rout-
ing tables?
a) Each day at midnight they download a new Internet map
from IMAP
b) They periodically ask neighboring routers for their network
tables
c) They randomly discard packets to trigger error-correction
code within the Internet
d) They are given transmission speed data by destination com-
puters
14. What is the purpose of the “Time to Live” field in a packet?
a) To make sure that packets do not end up in an “infinite loop”
b) To track how many minutes it takes for a packet to get
through the network
c) To maintain a mapping between network numbers and GPS
coordinates
d) To tell the router the correct output link for a particular
packet
15. How does the “traceroute” command work?
a) It sends a series of packets with low TTL values so it can get
a picture of where the packets get dropped
b) It loads a network route from the Internet Map (IMAP)
c) It contacts a Domain Name Server to get the route for a
particular network number
54 CHAPTER 4. INTERNETWORKING LAYER (IP)
d) It asks routers to append route information to a packet as it
is routed from source to destination
16. About how long does it take for a packet to cross the Pacific
Ocean via an undersea fiber optic cable?
a) 0.0025 Seconds
b) 0.025 Seconds
c) 0.250 Seconds
d) 2.5 Seconds
17. On a WiFi network, how does a computer get an Internet-
working (IP) address?
a) Using the DHCP protocol
b) Using the DNS protocol
c) Using the HTTP protocol
d) Using the IMAP protocol
18. What is Network Address Translation (NAT)?
a) It looks up the IP address associated with text names like
“www.dr-chuck.com”
b) It allows IPv6 traffic to go across IPv4 networks
c) It looks up the best outbound link for a particular router and
network number
d) It reuses special network numbers like “192.168” across mul-
tiple network gateways at multiple locations
19. How are IP addresses and network numbers managed glob-
ally?
a) There are five top-level registries that manage network num-
bers in five geographic areas
b) IP addresses are assigned worldwide randomly in a lottery
c) IP addresses are assigned by network equipment manufac-
turers
d) IP addresses are based on GPS coordinates
20. How much larger are IPv6 addresses than IPv4 addresses?
a) They are the same size
4.10. QUESTIONS 55
b) IPv6 addresses are 50% larger than IPv4 addresses
c) IPv6 addresses are twice as large as IPv4 addresses
d) IPv6 addresses are 10 times larger than IPv4 addresses
21. What does it mean when your computer receives an IP ad-
dress that starts with “169..”?
a) Your connection to the Internet supports the Multicast proto-
col
b) The gateway is mapping your local address to a global ad-
dress using NAT
c) There was no gateway available to forward your packets to
the Internet
d) The gateway for this network is a low-speed gateway with a
small window size
22. If you were starting an Internet Service Provider in Poland,
which Regional Internet Registry (RIR) would assign you a
block of IP addresses.
a) ARIN
b) LACNIC
c) RIPE NCC
d) APNIC
e) AFRNIC
f) United Nations
56 CHAPTER 4. INTERNETWORKING LAYER (IP)
Chapter 5
The Domain Name System
The Domain Name System lets you access websites by their
domain name like (www.khanacademy.org), so you don’t have
to keep a list of numeric Internet Protocol (IP) addresses like
“212.78.1.25”. IP address are determined by where your com-
puter connects to the Internet. When you have a portable
computer and you move from one location to another, you get
a new IP address at each new location. Since no one connects
to your portable computer, it does not matter if your IP address
changes from time to time. But since so many people connect to
a web server, it would be inconvenient if the server moved to a
new location and needed to change its IP address.
When your computer makes a connection to a system using a
domain name address, the first thing your computer does is look
up the IP address that corresponds to the domain name. Then
your computer makes the connection using the IP address.
Adding the separate step of looking up the IP address for a DNS
address also makes it easier to move a server from one location
to another. The server is given a new IP address and the entry for
the domain address is updated. Once the DNS entry is updated,
new requests for the domain name are given the new IP address.
Since end users access most servers using domain names and
never see the IP address, a server can be moved to a new network
connection without affecting the end user’s ability to access the
server.
57
58 CHAPTER 5. THE DOMAIN NAME SYSTEM
5.1 Allocating Domain Names
If you recall from the previous section, IP addresses are allocated
based on where you connect a new network to the Internet.
Domain names are allocated based on organizations that “own”
the domain name. At the top of the domain name hierarchy is
an organization called the International Corporation for Assigned
Network Names (ICANN). ICANN chooses the top-level domains
(TLDs) like .com, .edu, and .org and assigns those to other
organizations to manage. Recently a new set of TLDs like .club
and .help have been made available.
ICANN also assigns two-letter country code top-level domain
names like .us, .za, .nl, and .jp to countries around the world
We call these Country-Code Top-Level Domain Names (ccTLDs).
Countries often add second-level TLDs, like .co.uk for commercial
organizations within the UK. Policies for applying for domain
names with any particular ccTLD vary widely from one country to
another.
Figure 5.1: Domain Names
Once a domain name is assigned to an organization, the con-
trolling organization is allowed to assign subdomains within the
domain. As an example, the .edu top-level domain is assigned
5.2. READING DOMAIN NAMES 59
to the Educause organization. Educause assigns domains like
umich.edu to higher education institutions. Once the University
of Michigan is given control of umich.edu, it can make its own
choices for subdomains within its new domain. Domains ending
in .com and .org can be purchased by individuals. The individual
owners of those domains are allowed to manage their domain and
create subdomains under it for their own use or use by others.
5.2 Reading Domain Names
When we look at an IP address like “212.78.1.25”, the left prefix
is the “Network Number”, so in a sense we read IP addresses
from left to right, where the left part of the IP address is the most
general part of the address and right part of the address is most
specific:
212.78.1.25
Broad ----> Narrow
For domain names, we read from right to left:
drchuck.personal.si.umich.edu
Narrow <--- Broad
The most general part of this domain name is “.edu”, which
means higher education institutions. The subdomain “umich.edu”
is a particular higher education institution.
5.3 Summary
While the Domain Name System is not one of our four layers in
the model, it is an important part of making the Internet easier to
use. Domain names allow end users to use symbolic names for
servers instead of numeric Internet Protocol addresses. By adding
a service that maps domain names to IP addresses, we can move
servers from one Internet connection to another connection with-
out requiring users to manually change their configurations to
connect to a server.
If you would like to purchase a domain name for yourself or your
company, you can choose from any number of domain name reg-
istrars.
60 CHAPTER 5. THE DOMAIN NAME SYSTEM
5.4 Glossary
DNS: Domain Name System. A system of protocols and servers
that allow networked applications to look up domain names and
retrieve the corresponding IP address for the domain name.
domain name: A name that is assigned within a top-level do-
main. For example, khanacademy.org is a domain that is assigned
within the “.org” top-level domain.
ICANN: International Corporation for Assigned Network Names.
Assigns and manages the top-level domains for the Internet.
registrar: A company that can register, sell, and host domain
names.
subdomain: A name that is created “below” a domain
name. For example, “umich.edu” is a domain name and
both “www.umich.edu” and “mail.umich.edu” are subdomains
within “umich.edu”.
TLD: Top Level Domain. The rightmost portion of the domain
name. Example TLDs include “.com”, “.org”, and “.ru”. Recently,
new top-level domains like “.club” and “.help” were added.
5.5 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. What does the Domain Name System accomplish?
a) It allows network-connected computers to use a textual
name for a computer and look up its IP address
b) It keeps track of the GPS coordinates of all servers
c) It allows Regional Internet Registries (RIRs) to manage IP ad-
dresses on the various continents
d) It assigns different IP addresses to portable computers as
they move from one WiFi to another
2. What organization assigns top-level domains like “.com”,
“.org”, and “.club”?
a) IANA - Internet Assigned Numbers Authority
b) IETF - Internet Engineering Task Force
5.5. QUESTIONS 61
c) ICANN - International Corporation for Assigned Network
Names
d) IMAP - Internet Mapping Authorization Protocol
3. Which of these is a domain address?
a) 0f:2a:b3:1f:b3:1a
b) 192.168.3.14
c) www.khanacademy.org
d) @drchuck
4. Which of these is not something a domain owner can do with
their domain?
a) Create subdomains
b) Sell subdomains
c) Create new top-level domains
d) Assign an IP address to the domain or subdomain
62 CHAPTER 5. THE DOMAIN NAME SYSTEM
Chapter 6
Transport Layer
The next layer up from the Internetworking layer is the Transport
layer. A key element of the Internetworking layer is that it does
not attempt to guarantee delivery of any particular packet. The
Internetworking layer is nearly perfect, but sometimes packets
can be lost or misrouted.
Transport
Application
Internetwork
Link
Figure 6.1: The Transport Layer
But users of the network want to reliably send entire files or mes-
sages across the Internet. A network is not much good to us if
all it can do is send packets that are received most of the time.
For the network to be useful, all of the packets need to be re-
assembled into the right order to reconstruct the message on the
receiving system. The network must also deal with packets that
arrive out of order or never arrive at all. The Transport layer is
where we handle reliability and message reconstruction on the
63
64 CHAPTER 6. TRANSPORT LAYER
destination computer.
Just like the IP layer, the Transport layer adds a small amount of
data to each packet to help solve the problems of packet reassem-
bly and retransmission.
6.1 Packet Headers
If you were to look at a packet going across one of many links
between its source and destination computers, you would see a
link header, an IP header, and a Transport Control Protocol (TCP)
header, along with the actual data in the packet.
From | To
Link Header
From | To | TTL
IP Header
Port | Offset
TCP Header
…….
Data Packet
Figure 6.2: Headers and Data
The link header is removed when the packet is received on one
link and a new link header is added when the packet is sent out
on the next link on its journey. The IP and TCP headers stay with
a packet as it is going across each link in its journey. Remember
that a packet may go across several types of link layers as it is
routed through the Internet.
The IP header holds the source and destination Internet Protocol
(IP) addresses as well as the Time to Live (TTL) for the packet. The
IP header is set on the source computer and is unchanged (other
than the TTL) as the packet moves through the various routers on
its journey.
The TCP headers indicate where the data in each packet belongs.
As the source computer breaks the message or file into packets,
it keeps track of the position of each packet relative to the begin-
ning of the message or file and places the offset in each packet
that is created and sent.
6.2. PACKET REASSEMBLY AND RETRANSMISSION 65
6.2 Packet Reassembly and Retransmis-
sion
As the destination computer receives the packets, it looks at the
offset position from the beginning of the message so it can put
the packet into the proper place in the reassembled message.
Simply by making sure to put the packet data at the correct posi-
tion relative to the beginning of the message, the Transport layer
easily handles packets that arrive out of order. If it receives a
packet further down a message, it places that packet in a buffer,
keeping track of the fact that there is now a gap in the message
that is being reconstructed. When the earlier packet arrives a
moment later, it fits perfectly into the gap in the reassembled
data.
To avoid overwhelming the network, the Transport layer in the
sending computer only sends a certain amount of data before
waiting for an acknowledgement from the Transport layer on
the destination computer that the packets were received. The
amount of data that the sending computer will send before
pausing to wait for an acknowledgment is called the “window
size”.
The sending computer keeps track of how quickly it starts to
receive acknowledgements from the receiving computer. If the
acknowledgments come back quickly, the sending computer in-
creases its window size, but if the acknowledgments come back
slowly, the sending computer transmits less data. By adjusting
the window size, transmitting computers can send large amounts
of data quickly over fast connections that have light loads. When
sending data over slow or heavily loaded links, they can send the
data in a way that does not overwhelm the network.
If a packet is lost, it will never arrive at the destination computer
and so the destination computer will never send an acknowledg-
ment for that data. Because the sending computer does not re-
ceive an acknowledgment, it quickly reaches the point where it
has sent enough unacknowledged data to fill up the window and
stops sending new packets.
At this point, both computers are waiting. The sending computer
is waiting for an acknowledgement for a lost packet that will never
come and the receiving computer is waiting for a lost packet that
will never come. To make sure that the computers do not wait
forever, the destination computer keeps track of the amount of
time since it received the last packet of data. At some point, the
66 CHAPTER 6. TRANSPORT LAYER
receiving computer decides too much time has passed and sends
a packet to the sending computer indicating where in the stream
the receiving computer has last received data. When the sending
computer receives this message, it “backs up” and resends data
from the last position that the receiving computer had success-
fully received.
Figure 6.3: Waiting for a Lost Packet
The combination of the receiving computer acknowledging re-
ceived data, not allowing the transmitting computer to get too
far ahead (window size), and the receiving computer requesting
the sending computer to “back up and restart” when it appears
that data has been lost creates a relatively simple method to reli-
ably send large messages or files across a network.
While the Transport layer is sending a stream of data, it contin-
uously monitors how quickly it receives acknowledgements and
dynamically adjusts its window size. This ensures that data is
sent rapidly when the connection between two computers is fast
and much more slowly when the connection has slow links or a
heavy load.
6.3. THE TRANSPORT LAYER IN OPERATION 67
6.3 The Transport Layer In Operation
One of the key elements of the Transport layer is that the sending
computer must hold on to all of the data it is sending until the
data has been acknowledged. Once the receiving computer ac-
knowledges the data, the sending computer can discard the sent
data. We can look at this graphically when a message is broken
into many packets. Here, the first ten packets of the message
have been sent and acknowledged by the destination computer
(‘a’). The sending computer has sent six more packets (‘S’), and
then stopped because it reached its window size.
Source Message
Transport Layer
Destination Transport
Layer
PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
aaaaaaaaSSSSSS
aaaaaaaaRR R
S S S
Figure 6.4: Buffering in the Transport Layer
There are three packets that have been sent but not yet received
(“S”). Since there are many hops in the network, it is very com-
mon for more than one packet to be enroute in the network at the
same time.
The Transport layer on the receiving computer has received and
acknowledged ten packets and delivered them to the receiving
application (‘a’).1 The Transport layer on the destination com-
puter has received more three packets (‘R’), but one packet is out
of order. Receiving a packet out of order is not a cause for con-
cern if the missing packet arrives in a reasonably short amount
of time. As long as all the packets are received, the receiving
Transport layer will reconstruct the message, fitting the packets
together like puzzle pieces, and deliver them to the receiving ap-
plication.
1We talk about the Application layer in later material.
68 CHAPTER 6. TRANSPORT LAYER
6.4 Application Clients and Servers
The purpose of the Transport layer is to provide reliable connec-
tions between networked applications so those applications can
send and receive streams of data. For an application, this is as
simple as asking the Transport layer to make a connection to an
application running on a remote host. We call the application that
initiates the connection on the local computer the “client” and the
application that responds to the connection request the “server”.
We call the combination of the two networked applications at the
ends of the connection a “client/server” application because the
two pieces of the application must work together.
A lot of engineering has gone into the lower three layers of our
architecture to make it easy to open a connection to a remote
computer and then send and receive data over that connection.
6.5 Server Applications and Ports
When a client application wants to make a connection to a re-
mote computer, it is important that the connection is made to
the correct server application on that remote computer. A remote
computer might have any number of different server applications
running at the same time. Example server applications would
include:
• Web Server
• Video Server
• Mail Server
For instance, a web client (a browser) needs to connect to the web
server running on the remote computer. So a client application
not only needs to know which remote computer to connect to, it
also needs to choose a particular application to interact with on
that remote computer.
We use a concept called “ports” to allow a client application to
choose which server application it wants to interact with. Ports
are like telephone extensions. All of the extensions have the
same phone number (IP Address) but each extension (server ap-
plication) has a different extension number (port number).
When a server application starts up, it “listens” for incoming con-
nections on the specified port. Once the server application has
6.5. SERVER APPLICATIONS AND PORTS 69
Figure 6.5: TCP Ports
registered that it is ready to receive incoming connections, it
waits until the first connection is made.
So that client applications know which port to connect to, there is
a list of well-known default ports for various server applications:
• Telnet (23) - Login
• SSH (22) - Secure Login
• HTTP (80) - World Wide Web
• HTTPS (443) - Secure Web
• SMTP (25) - Incoming Mail
• IMAP (143/220/993) - Mail Retrieval
• POP (109/110) - Mail Retrieval
• DNS (53) - Domain Name Resolution
• FTP (21) - File Transfer
These are the normal ports for these applications. Sometimes
servers will make applications available at non-standard ports. If
you are doing web development, you may run a web server at a
non-standard port like 3000, 8080, or 8888. If you see a URL like:
http://testing.example.com:8080/login
70 CHAPTER 6. TRANSPORT LAYER
the “8080” indicates that your browser is going to use the web
protocols to interact with the server, but connect to port 8080
instead of the default port 80.
6.6 Summary
In a sense, the purpose of the Transport layer is to compensate
for the fact that the Link and Internetworking layers might lose
data. When the two lower layers lose or reroute packets, the
Transport layer works to reassemble and/or retransmit that data.
The existence of the Transport layer makes it possible for the two
lower layers to ignore retransmission and rate-limiting issues.
Part of the goal of a layered architecture is to break an overly
complex problem into smaller subproblems. Each layer focuses
on solving part of the overall problem and assumes that the other
layers solve the problems they are supposed to solve.
6.7 Glossary
acknowledgement: When the receiving computer sends a no-
tification back to the source computer indicating that data has
been received.
buffering: Temporarily holding on to data that has been sent or
received until the computer is sure the data is no longer needed.
listen: When a server application is started and ready to accept
incoming connections from client applications.
port: A way to allow many different server applications to be
waiting for incoming connections on a single computer. Each
application listens on a different port. Client applications make
connections to well-known port numbers to make sure they are
talking to the correct server application.
6.8 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. What is the primary problem the Transport (TCP) layer is sup-
posed to solve?
6.8. QUESTIONS 71
a) Move packets across multiple hops from a source to destina-
tion computer
b) Move packets across a single physical connection
c) Deal with lost and out-of-order packets
d) Deal with encryption of sensitive data
2. What is in the TCP header?
a) Physical address
b) IP Address and Time to Live
c) Port number and offset
d) Which document is being requested
3. Why is “window size” important for the proper functioning of
the network?
a) Because packets that are too large will clog fiber optic con-
nections
b) It prevents a fast computer from sending too much data on
a slow connection
c) It limits the number of hops a packet can take before it is
dropped
d) It determines what part of an IP address is the network num-
ber
4. What happens when a sending computer receives an ac-
knowledgement from the receiving computer?
a) The sending computer resends the data to make sure it was
transmitted accurately
b) The sending computer sends more data up to the window
size
c) The sending computer sends an “acknowledgment for the
acknowledgment”
d) The sending computer sends the acknowledgement to the
Internet Map (IMAP)
5. Which of these detects and takes action when packets are
lost?
a) Sending computer
b) Network gateway
72 CHAPTER 6. TRANSPORT LAYER
c) Core Internet routers
d) Receiving computer
6. Which of these retains data packets so they can be retrans-
mitted if a packets lost?
a) Sending computer
b) Network gateway
c) Core Internet routers
d) Receiving computer
7. Which of these is most similar to a TCP port?
a) Train station
b) Undersea network cable
c) Apartment number
d) Sculpture garden
8. Which half of the client/server application must start first?
a) Client
b) Server
9. What is the port number for the Domain Name System?
a) 22
b) 80
c) 53
d) 143
10. What is the port number for the IMAP mail retrieval protocol?
a) 22
b) 80
c) 53
d) 143
Chapter 7
Application Layer
We have been working from the bottom to the top of our four-
layer TCP/IP network model and we are finally at the top. The Ap-
plication layer is where the networked software like web browsers,
mail programs, video players, or networked video players operate.
We as users interact with these applications and the applications
interact with the network on our behalf.
Transport
Application
Internetwork
Link
Figure 7.1: The Application Layer
7.1 Client and Server Applications
It is important to remember that two parts are required for a net-
worked application to function. The architecture for a networked
73
74 CHAPTER 7. APPLICATION LAYER
application is called “client/server”. The server portion of the ap-
plication runs somewhere on the Internet and has the information
that users want to view or interact with. The client portion of the
application makes connections to the server application, retrieves
information, and shows it to the user. These applications use the
Transport layer on each of their computers to exchange data.
Figure 7.2: Client/Server Applications
To browse a web address like www.khanacademy.org, you must
have a web application running on your computer. When you type
an address into your web browser, it connects to the appropriate
web server, retrieves pages for you to view, and then shows you
the pages.
The web browser on your computer sends a request to connect
to www.khanacademy.org. Your computer looks up the domain
name to find the corresponding IP address for the server and
makes a transport connection to that IP address, then begins to
request data from the server over that network connection. When
the data is received, the web browser shows it to you. Sometimes
web browsers display a small animated icon to let you know that
the data is being retrieved across the network.
On the other end of the connection is another application called a
“web server”. The web server program is always up and waiting
for incoming connections. So when you want to see a web page,
you are connecting to a server application that is already running
and waiting for your connection.
In a sense, the Transport, Internetwork, and Link layers, along
7.2. APPLICATION LAYER PROTOCOLS 75
with the Domain Name System, are like a telephone network for
networked applications. They “dial up” different server applica-
tions on the network and have “conversations” with those appli-
cations to exchange data.
7.2 Application Layer Protocols
Just like people talking on telephones, each pair of network appli-
cations needs a set of rules that govern the conversation. In most
cultures, when your phone rings and you pick up the phone you
say “Hello”. Normally the person who made the call (the client
person) is silent until the person who picked up the phone (the
server person) says “Hello”. If you have ever called someone
who does not follow this simple rule, it can be quite confusing.
You probably would assume that the connection was not working,
hang up, and retry the call.
A set of rules that govern how we communicate is called a “proto-
col”. The definition of the word protocol is “a rule which describes
how an activity should be performed, especially in the field of
diplomacy.” The idea is that in formal situations, we should be-
have according to a precise set of rules. We use this word to
describe networked applications, because without precise rules,
applications have no way to establish and manage a conversa-
tion. Computers like precision.
There are many different networked applications and it is impor-
tant that each networked application have a well-documented
protocol so that all servers and clients can interoperate. Some
of these protocols are intricate and complex.
The protocol that describes how a web browser communicates
with a web server is described in a number of large documents
starting with this one:
https://tools.ietf.org/html/rfc7230
The formal name of the protocol between web clients and web
servers is the “HyperText Transport Protocol”, or HTTP for short.
When you put “http:” or “https:” on the beginning of a URL that
you type into the browser, you are indicating that you would like
to retrieve a document using the HTTP protocol.
If you were to read the above document, and go to section 5.3.2
on page 41, you find the exact text of what a web client is sup-
posed to send to a web server:
76 CHAPTER 7. APPLICATION LAYER
Figure 7.3: Application Protocols
GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
One of the reasons that HTTP is so successful is that it is relatively
simple compared to most client/server protocols. Even though
the basic use of HTTP is relatively simple, there is a lot of detail
that allows web clients and servers communicate efficiently and
transfer a wide range of information and data. Six different doc-
uments describe the HTTP protocol, in a total of 305 pages. That
might seem like a lot of detail, but the key in designing protocols
is to think through all possible uses of the protocol and describe
each scenario carefully.
7.3 Exploring the HTTP Protocol
In this section we will manually exercise the HTTP protocol by
pretending to be a web browser and sending HTTP commands to
a web server to retrieve data. To play with the HTTP protocol, we
will use one of the earliest Internet applications ever built.
The “telnet” application was first developed in 1968, and was
7.3. EXPLORING THE HTTP PROTOCOL 77
developed according to one of the earliest standards for the Inter-
net:
https://tools.ietf.org/html/rfc15
This standard is only five pages long and at this point, you prob-
ably can easily read and understand most of what is in the docu-
ment. The telnet client application is so old that it is effectively a
dinosaur, as it comes from “prehistoric” times in terms of the age
of the Internet. The Internet was created in 1985 by the NSFNet
project and the precursor to the NSFNet called the ARPANET was
brought up in 1969. Telnet was designed and built even before
the first TCP/IP network was in production.
Interestingly, the telnet application is still present in most mod-
ern operating systems. You can access telnet from the terminal
(command line) in Macintosh and Linux. The telnet application
was also present in Windows 95 through Windows XP, but is not
included in later versions of Windows. If you have a later version
of Windows, you can download and install a telnet client to do the
examples in this section.
Telnet is a simple application. Run telnet from the command line
(or terminal) and type the following command:
telnet www.dr-chuck.com 80
The first parameter is a domain name (an IP address would work
here as well) and a port to connect to on that host. We use the
port to indicate which application server we would like to connect
to. Port 80 is where we typically expect to find an HTTP (web)
server application on a host. If there is no web server listening
on port 80, our connection will time out and fail. But if there is
a web server, we will be connected to that web server and what-
ever we type on our keyboard will be sent directly to the server.
At this point, we need to know the HTTP protocol and type the
commands precisely as expected. If we don’t know the protocol,
the web server will not be too friendly. Here is an example of
things not going well:
telnet www.dr-chuck.com 80
Trying 198.251.66.43...
Connected to www.dr-chuck.com.
Escape character is '^]'.
HELP
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
78 CHAPTER 7. APPLICATION LAYER
<html><head>
<title>501 Method Not Implemented</title>
...
</body></html>
Connection closed by foreign host.
We type “telnet” in the terminal requesting a connection to port
80 (the web server) on the host www.dr-chuck.com. You can see
as our transport layer is looking up the domain name, finding
that the actual address is “198.251.66.43”, and then making a
successful connection to that server. Once we are connected, the
server waits for us to type a command followed by the enter or
return key. Since we don’t know the protocol, we type “HELP” and
enter. The server is not pleased, gives us an error message, and
then closes the connection. We do not get a second chance. If we
do not know the protocol, the web server does not want to talk to
us.
But let’s go back and read section 5.3.2 of the RFC-7230 docu-
ment and try again to request a document using the correct syn-
tax:
telnet www.dr-chuck.com 80
Trying 198.251.66.43...
Connected to www.dr-chuck.com.
Escape character is '^]'.
GET http://www.dr-chuck.com/page1.htm HTTP/1.0
HTTP/1.1 200 OK
Last-Modified: Sun, 19 Jan 2014 14:25:43 GMT
Content-Length: 131
Content-Type: text/html
<h1>The First Page</h1>
<p>
If you like, you can switch to the
<a href="http://www.dr-chuck.com/page2.htm">
Second Page</a>.
</p>
Connection closed by foreign host.
We make the connection to the web browser again using telnet,
then we send a GET command that indicates which document we
want to retrieve. We use version 1.0 of the HTTP protocol because
7.3. EXPLORING THE HTTP PROTOCOL 79
Figure 7.4: Hacking HTTP By Hand
it is simpler than HTTP 1.1. Then we send a blank line by pressing
“return” or “enter” to indicate that we are done with our request.
Since we have sent the proper request, the host responds with a
series of headers describing the document, followed by a blank
line, then it sends the actual document.
The headers communicate metadata (data about data) about the
document that we have asked to retrieve. For example, the first
line contains a status code.
In this example, the status code of “200” means that things went
well. A status code of “404” in the first line of the headers in-
dicates that the requested document was not found. A status
code of “301” indicates that the document has moved to a new
location.
The status codes for HTTP are grouped into ranges: 2XX codes in-
dicate success, 3XX codes are for redirecting, 4XX codes indicate
that the client application did something wrong, and 5xx codes
indicate that the server did something wrong.
This is a HyperText Markup Language (HTML) document, so it is
marked up with tags like <h1> and <p>. When your browser
receives the document in HTML format, it looks at the markup in
the document, interprets it, and presents you a formatted version
of the document.
80 CHAPTER 7. APPLICATION LAYER
7.4 The IMAP Protocol for Retrieving Mail
The HTTP protocol is only one of many client/server application
protocols used on the Internet. Another common protocol is used
so that a mail application running on your computer can retrieve
mail from a central server. Since your personal computer might
not be turned on at all times, when mail is sent to you it is sent to
a server and stored on that server until you turn on your computer
and retrieve any new email.
Like many application standards, the Internet Message Access
Protocol (IMAP) is described in a series of Request For Comment
(RFC) documents starting with this RFC:
https://tools.ietf.org/html/rfc3501
IMAP is a more complicated protocol than the web protocol, so
we won’t be able to use the telnet command to fake the protocol.
But if you were going to develop a mail reading application, you
could carefully read this document and develop code to have a
successful conversation with a standards-compliant IMAP server.
Here is a simple example from section 6.3.1 of the above docu-
ment showing what the client (C:) sends and how the server (S:)
responds:
C: A142 SELECT INBOX
S: * 172 EXISTS
S: * 1 RECENT
S: * OK [UNSEEN 12] Message 12 is first unseen
S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: * OK [UIDNEXT 4392] Predicted next UID
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited
S: A142 OK [READ-WRITE] SELECT completed
The messages that are sent by the client and server are not de-
signed to be viewed by an end user so they are not particularly
descriptive. These messages are precisely formatted and are sent
in a precise order so that they can be generated and read by net-
worked computer applications on each end of the connection.
7.5. FLOW CONTROL 81
7.5 Flow Control
When we looked at the Transport layer, we talked about the “win-
dow size”, which was the amount of data that the Transport layer
on the sending computer will send before pausing to wait for an
acknowledgement.
Source Message
Transport Layer
Destination Transport
Layer
PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
aaaaaaaaSSSSSS
aaaaaaaaRR R
S S S
Figure 7.5: Buffering in the Transport Layer
In this figure, we see a message broken into packets, with some
of the packets sent and acknowledged. Six packets have been
sent but not yet acknowledged and the sending Transport layer
has reached the limit of the transmit window, so it is pausing un-
til it receives an acknowledgement from the receiving computer’s
Transport layer. The receiving computer has received three pack-
ets, one of which is out of order.
When we were looking at this example before from the point of
view of the Transport layer, we ignored where the packets to be
sent were coming from and where the packets were going to in
the receiving computer. Now that we are looking at the Applica-
tion layer, we can add the two applications that are the source
and the destination of the stream of data.
Let’s assume the web browser has made a transport connection
to the web server and has started downloading an image file. The
web server has opened the image file and is sending the data
from the file to its Transport layer as quickly as possible. But the
Transport layer must follow the rules of window size, so it can only
send a certain amount of data at a time. When the window fills up,
the web server is paused until the Transport layer on the destina-
tion computer has started to receive and acknowledge packets.
As the Transport layer on the destination computer starts to re-
82 CHAPTER 7. APPLICATION LAYER
ceive packets, reconstruct the stream of data, and acknowledge
packets, it delivers the reconstructed stream of packets to the
web browser application display on the user’s screen. Sometimes
on a slow connection you can see your browser “paint” pictures
as the data is downloaded. On a fast connection the data comes
so quickly that the pictures appear instantaneously.
If we redraw our picture of packets in the Transport layer, adding
both of the application layers where the packets are in the middle
of an image, now it looks like this:
Web Server Application
Transport Transport Web Browser Application
Internetwork and Link Layers
..aSSSSSS ..aRR R AAAA
AAAA
AA.. ...FFFFF
S S S
ACK
Figure 7.6: Buffering in the Application and Transport Layers
The web server is reading the image file (‘F’) and sending it as
a stream to the web browser as quickly as it can send the data.
The source Transport layer has broken the stream into packets
and used IP to send the packets to the destination computer.
The Transport layer has sent six packets (‘S’) and has stopped
sending because it has reached its window size and paused the
web server. Three of those six packets have made it to the Trans-
port layer on the destination computer (‘R’) and three of the pack-
ets are still making their way across the Internet (‘S’).
As the destination Transport layer pieces the stream back to-
gether, it both sends an acknowledgement (ACK) and delivers
the data to the receiving application (the web browser). The web
browser reconstructs the image (‘A’) and displays it to the user
as the data is received.
A key thing to notice in this picture is that the transport layers do
not keep the packets for the entire file. They only retain packets
that are “in transit” and unacknowledged. Once packets are ac-
knowledged and delivered to the destination application, there is
no reason for either the source or destination Transport layer to
hold on to the packets.
When the acknowledgment flows back from the destination
computer to the source computer, the Transport layer on the
7.6. WRITING NETWORKED APPLICATIONS 83
source computer unpauses the web server application and the
web server continues to read data from the file and send it to the
source Transport layer for transmission.
This ability to start and stop the sending application to make sure
we send data as quickly as possible without sending data so fast
that they clog up the Internet is called “flow control”. The applica-
tions are not responsible for flow control, they just try to send or
receive data as quickly as possible and the two transport layers
start and stop the applications as needed based on the speed and
reliability of the network.
7.6 Writing Networked Applications
The applications which send and receive data over the network
are written in one or more programming languages. Many pro-
gramming languages have libraries of code that make it quite
simple to write application code to send and receive data across
the network. With a good programming library, making a connec-
tion to an application running on a server, sending data to the
server, and receiving data from the server is generally as easy as
reading and writing a file.
As an example, the code below is all it takes in the Python pro-
gramming language to make a connection to a web server and
retrieve a document:
import socket mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) mysock.connect(('www.py4inf.com', 80)) mysock.send('GET http://www.py4inf.com/code/romeo.txt HTTP/1.0\n\n')
while True: data = mysock.recv(512) if ( len(data) < 1 ) : break print data
mysock.close()
Figure 7.7: Programming with Sockets in Python
While you may or not know the Python programming language,
the key point is that it only takes ten lines of application code to
make and use a network connection. This code is simple because
the Transport, Internetwork, and Link layers so effectively solve
84 CHAPTER 7. APPLICATION LAYER
the problems at each of their layers that applications using the
network can ignore nearly all of the details of how the network is
implemented.
In the Python application, in this line of code
mysock.connect(('www.py4inf.com', 80))
we have specified that we are connecting to the application that
is listening for incoming connections on port 80 on the remote
computer www.py4inf.com.
By choosing port 80 we are indicating that we want to connect to
a World Wide Web server on that host and are expecting to com-
municate with that server using the HyperText Transport Protocol.
7.7 Summary
The entire purpose of the lower three layers (Transport, Internet-
work, and Link) is to make it so that applications running in the
Application layer can focus the application problem that needs to
be solved and leave virtually all of the complexity of moving data
across a network to be handled by the lower layers of the network
model.
Because this approach makes it so simple to build networked
applications, we have seen a wide range of networked applica-
tions including web browsers, mail applications, networked video
games, network-based telephony applications, and many others.
And what is even more exciting is that it is easy to experiment
and build whole new types of networked applications to solve
problems that have not yet been imagined.
7.8 Glossary
HTML: HyperText Markup Language. A textual format that
marks up text using tags surrounded by less-than and
greater-than characters. Example HTML looks like: <p>This
is <strong>nice</strong></p>.
HTTP: HyperText Transport Protocol. An Application layer proto-
col that allows web browsers to retrieve web documents from web
servers.
7.9. QUESTIONS 85
IMAP: Internet Message Access Protocol. A protocol that allows
mail clients to log into and retrieve mail from IMAP-enabled mail
servers.
flow control: When a sending computer slows down to make
sure that it does not overwhelm either the network or the desti-
nation computer. Flow control also causes the sending computer
to increase the speed at which data is sent when it is sure that
the network and destination computer can handle the faster data
rates.
socket: A software library available in many programming lan-
guages that makes creating a network connection and exchang-
ing data nearly as easy as opening and reading a file on your
computer.
status code: One aspect of the HTTP protocol that indicates
the overall success or failure of a request for a document. The
most well-known HTTP status code is “404”, which is how an HTTP
server tells an HTTP client (i.e., a browser) that it the requested
document could not be found.
telnet: A simple client application that makes TCP connections
to various address/port combinations and allows typed data to be
sent across the connection. In the early days of the Internet, tel-
net was used to remotely log in to a computer across the network.
web browser: A client application that you run on your computer
to retrieve and display web pages.
web server: An application that deliver (serves up) Web pages
7.9 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. Which layer is right below the Application layer?
a) Transport
b) Internetworking
c) Link Layer
d) Obtuse layer
2. What kind of document is used to describe widely used Ap-
plication layer protocols?
86 CHAPTER 7. APPLICATION LAYER
a) DHCP
b) RFC
c) APPDOC
d) ISO 9000
3. Which of these is an idea that was invented in the Applica-
tion layer?
a) 0f:2a:b3:1f:b3:1a
b) 192.168.3.14
c) www.khanacademy.com
d) http://www.dr-chuck.com/
4. Which of the following is not something that the Application
layer worries about?
a) Whether the client or server starts talking first
b) The format of the commands and responses exchanged
across a socket
c) How the window size changes as data is sent across a socket
d) How data is represented as it is sent across the network to
assure interoperability.
5. Which of these is an Application layer protocol?
a) HTTP
b) TCP
c) DHCP
d) Ethernet
6. What port would typically be used to talk to a web server?
a) 23
b) 80
c) 103
d) 143
7. What is the command that a web browser sends to a web
server to retrieve an web document?
a) RETR
7.9. QUESTIONS 87
b) DOCUMENT
c) 404
d) GET
8. What is the purpose of the “Content-type:” header when you
retrieve a document over the web protocol?
a) Tells the browser how to display the retrieved document
b) Tells the browser where to go if the document cannot be
found
c) Tells the browser whether or not the retrieved document is
empty
d) Tells the browser where the headers end and the content
starts
9. What common UNIX command can be used to send simple
commands to a web server?
a) ftp
b) ping
c) traceroute
d) telnet
10. What does an HTTP status code of “404” mean?
a) Document has moved
b) Successful document retrieval
c) Protocol error
d) Document not found
11. What characters are used to mark up HTML documents?
a) Less-than and greater-than signs < >
b) Exclamation points !
c) Square brackets [ ]
d) Curly brackets { }
12. What is a common application protocol for retrieving mail?
a) RFC
b) HTML
88 CHAPTER 7. APPLICATION LAYER
c) ICANN
d) IMAP
13. What application protocol does RFC15 describe?
a) telnet
b) ping
c) traceroute
d) www
14. What happens to a server application that is sending a large
file when the TCP layer has sent enough data to fill the win-
dow size and has not yet received an acknowledgement?
a) The application switches its transmission to a new socket
b) The application crashes and must be restarted
c) The application is paused until the remote computer
acknowledges that it has received some of the data
d) The closest gateway router starts to discard packets that
would exceed the window size
15. What is a “socket” on the Internet?
a) A way for devices to get wireless power
b) A way for devices to get an IP address
c) An entry in a routing table
d) A two-way data connection between a pair of client and
server applications
16. What must an application know to make a socket connection
in software?
a) The address of the server and the port number on the server
b) The route between the source and destination computers
c) Which part of the IP address is the network number
d) The initial size of the TCP window during transmission
Chapter 8
Secure Transport Layer
In the early days of the Internet, networks were small and all of
the routers were in secure locations. As long as each computer
connected to the Internet protected itself from unwanted incom-
ing connections, it was felt that there was no need to protect data
from prying eyes while it was crossing the network.
So the Link, Internetwork, and Transport layers were focused on
the efficient movement of data and solving the problems of a
large-scale shared distributed network without worrying about
the privacy of that data.
But as the use of the Internet grew rapidly in the late 1980s and
literally exploded when the Web became mainstream in 1994, se-
curity and privacy of network traffic became very important prob-
lems to solve. When we began using the Internet to conduct com-
merce and credit cards and bank account numbers were being
routinely sent across the network, securing data became essen-
tial. And when we started using wireless technologies like WiFi,
security became necessary for even the simplest uses of the In-
ternet.
There are two general approaches to securing network activity.
The first makes sure that all of the network hardware (routers
and links) is in physically secure locations so it is not possible for
someone to sneak in and monitor traffic while it is crossing the
Internet. This approach is not practical for hundreds of thousands
of network routers owned and operated by many different orga-
nizations. While you might be able to ensure that some of the
router operators adhered to strict security procedures and poli-
cies, sooner or later a mistake will be made. And once WiFi was
added to the mix and your packets went over radio waves, a net-
work attacker could just sit in a coffee shop and intercept packets
89
90 CHAPTER 8. SECURE TRANSPORT LAYER
as they passed through the air.
Under these conditions, the only reasonable solution is to encrypt
data in your computer before it is sent across its first physical
link, and then decrypt the data in the destination computer after
it arrives. Using this approach, we assume that an attacker can
see all of the packets that you send, but they cannot decrypt the
data that they have captured. The encryption also guarantees
that there is no way to alter your data while it is crossing the
Internet.
8.1 Encrypting and Decrypting Data
The concept of protecting information so it cannot be read while
it is being transported over an insecure medium is thousands of
years old. The leaders in Roman armies sent coded messages to
each other using a code called the “Caesar Cipher”. The simplest
version of this approach is to take each of the characters of the
actual message (we call this “plain text”) and shift each charac-
ter a fixed distance down the alphabet to produce the scrambled
message or “ciphertext”.
Then we send the ciphertext via the courier or other insecure
transport to the other person. The courier cannot read the mes-
sage because it appears to be random characters unless you
know the technique used to encode the message.
As long as the person receiving the message knew the number
used to shift the message, they could unshift the characters in
the encoded message to reproduce the original message.
Here is a simple example of plain text and ciphertext using a shift
of one:
Plain text: Go to the river
Cipher text: Hp up uif sjwfs
We use the word “encrypt” to describe transforming the plain text
to the ciphertext and “decrypt” to describe the reverse process.
The Caesar Cipher is very simple to defeat, but it was used to
protect important messages until about 150 years ago. Modern
encryption techniques are far more sophisticated than a simple
character shift, but all encryption systems depend on some kind
of a secret key that both parties are aware of so they can decrypt
received data.
8.2. TWO KINDS OF SECRETS 91
8.2 Two Kinds of Secrets
The traditional way to encrypt transmissions is using a shared se-
cret (a password, a sentence, a number) that only the sending
and receiving parties know. With the secret, it is easy to decrypt
the received data, but if you received the data without possess-
ing the secret, it would be effectively impossible to decrypt the
message.
Figure 8.1: Shared Versus Asymmetric Keys
In the early days of the Internet, two people could send encrypted
email to each other by one person first calling the other person
on the phone and giving them the decryption secret. This worked
well when there were only a few users on the network, but could
not scale to situations where a company might have millions of
customers and could not afford to make a phone call to each cus-
tomer to establish a shared secret before they could make a pur-
chase.
It might seem like a good idea to distribute the shared secrets
over the Internet, but if we assume that the attackers are monitor-
ing and capturing all network traffic, they could also capture the
unencrypted message that contained the shared secret. At that
point it would be trivial for the attacker to use the shared secret
to decrypt a message. And even worse, the attacker could inter-
cept a message, delay it, then decrypt it, change and re-encrypt
it, and send the modified message back on its way. The receiving
92 CHAPTER 8. SECURE TRANSPORT LAYER
computer would decrypt the message and never know that it had
been modified by an attacker while in transit.
So shared secrets clearly would not work to solve the problem of
securing network traffic between trillions of pairs of networked
computers.
The solution to this problem came in the 1970s when the con-
cept of asymmetric key encryption was developed. The idea of
asymmetric key encryption is that one key is used to encrypt the
message and another key is used to decrypt it. The computer that
will be receiving the encrypted data chooses both the encryption
key and decryption key. Then the encryption key is sent to the
computer that will be sending the data. The sending computer
encrypts the data and sends it across the network. The receiving
computer uses the decryption key to decrypt the data.
We call the encryption key the “public” key because it can be
widely shared. We call the decryption key the “private” key be-
cause it never leaves the computer where it was created. Another
name for asymmetric keys is public/private keys.
The whole process is designed so that if an attacker has the public
key (which was sent unencrypted) and the encrypted text, it is
virtually impossible to decrypt the encrypted data. There is a lot
of math with large prime numbers that makes it hard to guess the
private key from the public key and encrypted data.
So with the advent of public/private key technology, the only
question left was how to apply it in our network model.
8.3 Secure Sockets Layer (SSL)
Since network engineers decided to add security nearly 20 years
after the Internet protocols were developed, it was important not
to break any existing Internet protocols or architecture. Their so-
lution was to add an optional partial layer between the Transport
layer and the Application layer. They called this partial layer the
Secure Sockets Layer (SSL) or Transport Layer Security (TLS).
When an application requested that the Transport layer make a
connection to a remote host, it could request that the connec-
tion either be encrypted or unencrypted. If an encrypted connec-
tion was requested, the Transport layer encrypted the data before
breaking the stream into packets. This meant that the Transport
layer, Internetwork layer, and physical (link) layers could still per-
form exactly the same way whether the packets were encrypted
8.4. ENCRYPTING WEB BROWSER TRAFFIC 93
Figure 8.2: Where Encryption and Decryption Happens
or non-encrypted. The applications making the connections were
also spared the details of how encryption and decryption worked.
Since encryption was a simple and transparent addition to the
Transport layer, there was no need to change the routers that
operate at the Internetwork and Link layers. There was no need
to change any Link layer hardware to make encryption work. And
applications did not need to be modified except to request that a
connection be encrypted when appropriate.
8.4 Encrypting Web Browser Traffic
Since web browsers and web servers operate at the application
layer, we barely notice whether we are using encrypted or un-
encrypted connections. Web browsers use the URL convention
of replacing “http:” with “https:” to indicate that the browser is
to communicate with the web server using the Secure Transport
Layer instead of the unencrypted Transport layer. Your browser
will usually show a “lock” icon in the address bar to let you know
that you are communicating with a secure web site.
94 CHAPTER 8. SECURE TRANSPORT LAYER
There is a small overhead in setting up the https connections and
a small cost to encrypt and decrypt the data that is being sent.
Since https was slightly more costly, for a while it was used only
for pages that contained passwords, bank account numbers, or
other sensitive data.
But over time as networks have become faster and the https im-
plementations have gotten much more efficient, there is a trend
toward encrypting all web server interactions whenever you are
interacting with a web server where you have an account. The
current trend is towards using https for all web traffic.
8.5 Certificates and Certificate Authorities
While public/private key encryption works to allow the distribution
of encryption keys across insecure networks and the use of those
keys to encrypt transmissions, there is still a problem of knowing
if the public key that you have received when you connected to a
server is really from the organization it claims to be from.
Figure 8.3: Certificate Authorities and Public Keys
Perhaps you think you are connecting to www.amazon.com
but a rogue computer intercepts your traffic, claiming to be
8.6. SUMMARY 95
www.amazon.com and giving you a public key to use for encryp-
tion. If your web browser trusts the key, it will use the rogue
computer’s public key to encrypt your banking information and
send it to the rogue computer. Since the rogue computer gave
you the public key, it also has the corresponding private key and
is able to decrypt and abscond with your banking information.
So your computer needs to know who the key is actually coming
from. This is achieved by sending you a public key that is digi-
tally signed by a Certificate Authority (CA). When your computer
or browser is initially installed, it knows about a number of well-
known certificate authorities. If your browser is given a public
key that is signed by one of the well-known certificate authorities,
it trusts the key and uses it to encrypt and send your data. If
your computer receives a public key that is not signed by one of
its trusted certificate authorities, it will warn you before sending
your data using the key.
If you see a warning message about an untrusted certificate, you
should probably say “no” and figure out why your network traffic
is not being routed to the server that you think it is going to before
sending any sensitive data.
8.6 Summary
Since the Internet was nearly 20 years old before we needed
broadly deployed security, we had to find a way to add security to
the already existing four-layer model. The perfect place to add se-
curity was as an option in the Transport layer. This is why we call
secure connections on the Internet “Secure Sockets Layer” (SSL)
or “Transport Layer Security” (TLS). There are subtle differences
between SSL and TLS but they both encrypt data at the Transport
layer.
The invention of public/private key encryption was well timed in
that it solved the key distribution problem of shared-secret en-
cryption approaches. With public/private keys, the public encryp-
tion key can be routinely shared across insecure media. This
means we can use an unencrypted connection to exchange data
and upgrade the connection to a secure connection.
By inserting the secure layer at the top of the Transport layer, we
were able to avoid changing the Application, Internetwork, and
Link layers while still easily securing any Transport layer connec-
tion. This approach ensures that all data being sent across a con-
nection is encrypted before it leaves your computer. Given that
96 CHAPTER 8. SECURE TRANSPORT LAYER
many of us use wireless connections like WiFi, which are easily
monitored by attackers, it is a good idea to encrypt data before it
is sent across WiFi.
Browsers support secure connections by changing the prefix on
the URL from “http:” to “https:”. By keeping an eye on the URL,
end users can make sure they never send sensitive data across
insecure connections. A series of trusted Certificate Authorities
will sign public keys to give you an assurance that the key you
received is indeed from the organization you expect it to be.
The design of the Secure Transport Layer provides a secure and
yet easy-to-use mechanism for secure communications across
the Internet at a scale of trillions of pairs of interacting comput-
ers.
8.7 Glossary
asymmetric key: An approach to encryption where one (public)
key is used to encrypt data prior to transmission and a different
(private) key is used to decrypt data once it is received.
certificate authority: An organization that digitally signs public
keys after verifying that the name listed in the public key is actu-
ally the person or organization in possession of the public key.
ciphertext: A scrambled version of a message that cannot be
read without knowing the decryption key and technique.
decrypt: The act of transforming a ciphertext message to a plain
text message using a secret or key.
encrypt: The act of transforming a plain text message to a ci-
phertext message using a secret or key.
plain text: A readable message that is about to be encrypted
before being sent.
private key: The portion of a key pair that is used to decrypt
transmissions.
public key: The portion of a key pair that is used to encrypt
transmissions.
shared secret: An approach to encryption that uses the same
key for encryption and decryption.
SSL: Secure Sockets Layer. An approach that allows an appli-
cation to request that a Transport layer connection is to be en-
8.8. QUESTIONS 97
crypted as it crosses the network. Similar to Transport Layer Se-
curity (TLS).
TLS: Transport Layer Security. An approach that allows an ap-
plication to request that a Transport layer connection is to be en-
crypted as it crosses the network. Similar to Secure Sockets Layer
(SSL).
8.8 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. How do we indicate that we want a secure connection when
using a web browser?
a) Use https:// in the URL
b) Use a secure web browser
c) Open an incognito window
d) Manually encode the address of the server using SHA1
2. Why is a shared-secret approach not suitable for use on the
Internet?
a) Because people would lose or misplace the secret
b) It is difficult to distribute the secrets
c) Encryption and decryption with shared secrets are too easily
broken
d) Encryption and decryption with shared secrets take too
much compute power
3. What is the underlying mathematical concept that makes
public/private key encryption secure?
a) Continuous functions
b) Taylor series
c) Karnaugh Maps
d) Prime numbers
4. Which of the keys can be sent across the Internet in plain
text without compromising security?
98 CHAPTER 8. SECURE TRANSPORT LAYER
a) Encryption key
b) Decryption Key
c) Shared Secret
d) Univerally Safe Key (USK)
5. Where does the Secure Sockets Layer (SSL) fit in the four-
layer Internet architecture?
a) Below the Link layer
b) Between the Link and Internetworking layers
c) Between the Internetworking and Transport layers
d) Between the Transport and Application layers
6. If you were properly using https in a browser over WiFi in a
cafe, which of the following is the greatest risk to your losing
credit card information when making an online purchase?
a) Someone captured the packets that were sent across the
WiFi
b) Someone captured the packets in the gateway router
c) Someone captured the packets as they passed through a
core Intenet router
d) You have a virus on your computer that is capturing
keystrokes
7. With the Secure Sockets Layer, where are packets encrypted
and decrypted?
a) They are encrypted and decrypted as they pass through the
router
b) Each physical link has its own separate encryption
c) They are encrypted in your computer and decrypted in the
server
d) They are encrypted in the WiFi gateway and decrypted in the
last router before the destination computer
8. What changes to the IP layer were needed to make secure
socket layer (SSL) work?
a) No changes were needed
b) We had to add support for Secure IP (IPSEC)
c) We needed to support longer packets in IP
8.8. QUESTIONS 99
d) The Time-To-Live (TTL) value needed to be encrypted
9. If a rogue element was able to monitor all packets going
through an undersea cable and you were using pub-
lic/private key encryption properly, which of the following
would be the most difficult for them to obtain?
a) What servers you were communicating with
b) How often you used the servers
c) How much data you retrieved from the servers
d) Which documents you retrieved from the servers
10. What is the purpose of a Certificate Authority in pub-
lic/private key encryption?
a) To make sure people do not forge badges for learning activi-
ties
b) To make sure packets get routed to the correct destination
computer
c) To assure us that a public key comes from the organization
it claims to be from
d) To choose when a particular country must switch from IPv4
to IPv6
11. The ARPANET network was in operation starting in the 1960s.
Secure Sockets Layer (SSL) was not invented util the 1980s.
How did the ARPANET insure the security of the data on its
network?
a) By using public/private keys and encrypting all transmis-
sions
b) By using encryption at the Link layer
c) By making sure no one could access the physical links
d) By only using secure WiFi routers
12. Which of these answers is “Security is fun” encrypted with a
Caesar Cipher shift of 1.
a) Ptsjduao rt dii
b) Wentudhs di dju
c) Tfdvsjuz jt gvo
d) Asdfghjk qw zxc
100 CHAPTER 8. SECURE TRANSPORT LAYER
13. What Caesar Cipher shift was used to encrypt “V yvxr fr-
phevgl”?
a) 1
b) 6
c) 13
d) 24
Chapter 9
The OSI Model
So far we have spent all of our time describing the four-layer
model used to design and implement the TCP/IP protocols and ap-
plications that make up the Internet. However, the TCP/IP model
is not the only model we can use to help us understand how net-
works work. The other model commonly used to make sense of
network design is called the Open System Interconnection (OSI)
model. While the TCP/IP model was designed and evolved as the
TCP/IP protocols were developed, deployed, and changed, the OSI
model was the result of a careful design process by many net-
working experts who worked to develop a general approach to
network models.
In today’s networked world, the OSI model and the TCP/IP model
serve two different purposes.1 The TCP/IP model is an implemen-
tation model, in that it provides the guidance for those who would
build TCP/IP-compatible network hardware or software. The OSI
model is more of an abstract model that can be used to under-
stand a wide range of network architectures.
While TCP/IP is the most widely used network technology today,
many different types of networks have been implemented and de-
ployed over the past 50 years. And as we continue to improve and
evolve networking, new implementation models may emerge.
The OSI model has seven layers instead of the four layers of the
TCP/IP model. Starting at the bottom (nearest the physical con-
nections) of the OSI model, the layers are: (1) Physical, (2) Data
Link, (3) Network, (4) Transport, (5) Session, (6) Presentation, and
1This, of course, is an oversimplification. Prior to 1990, there were opera-
tional network implementations based on ISO specifications that followed the
OSI network model very closely. But today, those ISO/OSI network implementa-
tions no longer are in broad use.
101
102 CHAPTER 9. THE OSI MODEL
(7) Application. We will look at each layer in the OSI model in turn,
starting with the Physical layer.
9.1 Physical (Layer 1)
The OSI Physical layer deals with the physical attributes of the
actual wired, wireless, fiber optic, or other connection that is used
to transport data across a single link. The Physical layer also
defines the shapes of the connectors and type of media which can
be used. Another problem solved at this layer is how to encode
the bits (0’s and 1’s) that make up the data being sent across the
medium.2 The “bit encoding” (or modulation) determines how
fast data can be sent across the link.
9.2 Data Link (Layer 2)
The OSI Data Link layer is concerned with how the systems using
a physical link cooperate with one another. When data is broken
into packets, the Data Link layer defines special sequences to indi-
cate the beginning and end of each packet. The stations commu-
nicating using the physical connection are assigned addresses to
allow for effective use of the media. Sometimes multiple stations
are sharing the same media (as on a wireless network) and the
Data Link layer defines how those stations will share the connec-
tions with the other systems connected to the network. Most Data
Link layers also have some form of checksum to detect and/or cor-
rect for errors in the transmitted data.
The design problems solved in the Physical and Data Link layers
of the OSI model are addressed by the Link layer of the TCP/IP
model.
9.3 Network (Layer 3)
Like the Internetwork Layer (IP) in the TCP/IP model, the OSI Net-
work layer deals with the global assignment of “routable” ad-
dresses to the various systems connected to the network. The
2“Manchester Encoding” is a common technique for encoding bits for trans-
mission across a wire.
9.4. TRANSPORT (LAYER 4) 103
Network layer governs how routers forward packets across mul-
tiple hops to get from their source to their destination. Like the
IP layer, The OSI Network layer does not attempt to be error free,
as it assumes that lost data will be detected and retransmitted at
the next layer up.
9.4 Transport (Layer 4)
The Transport layer in the OSI model manages packet loss and
retransmission as well as flow control and window size. The rest
of the functionality of the TCP/IP Transport layer is handled in the
Session layer in the OSI model.
9.5 Session (Layer 5)
The OSI Session layer handles establishing connections between
applications. The Session layer deals with “ports” so that a con-
necting client application can “find” the correct server application
on a particular system. Some aspects of secure transmission are
also handled in the OSI Session layer.
9.6 Presentation (Layer 6)
The Presentation layer focuses on how data is represented and
encoded for transmission across the network. As an example, the
Presentation layer would describe how to encode the pixels of an
image so that the receiving application can properly decode the
data. The Presentation layer also handles data encryption and
decryption.
9.7 Application (Layer 7)
The OSI Application Layer is very similar to the Application layer
in the TCP/IP model, in that it contains the applications them-
selves. Some applications are client applications that initiate
connections, and other applications are the server applications
that respond to those connection requests. The various pairs of
applications have protocol standards that define interoperability
104 CHAPTER 9. THE OSI MODEL
between multiple clients and multiple servers from different ven-
dors.
Transport
Application
Internetwork
Link
Application
Transport
Data Link
Physical
Protocols
Encoding formats
Encryption/SSL
Ports
Reliability
Addressing / Routing
Addressing / Coordination
Voltages / Frequencies Speeds / Connectors
Figure 9.1: Comparing the TCP and OSI Models
9.8 Comparing the OSI and TCP/IP Models
We can use the OSI model to provide an alternative “view” of the
TCP/IP model by comparing how the OSI model breaks network
functionality into its layers and how the TCP/IP model breaks its
functionality into layers.
9.9 Link Layer (TCP/IP)
The TCP/IP Link layer combines the Physical and Data Link layers
from the OSI model. The Physical and Data Link layers are usually
implemented in hardware. Products like Ethernet, WiFi, satellite,
or fiber optic often are implemented in a network driver card that
plugs into the back of a computer or router. The network driver
card generally implements both the physical and the data link
9.10. INTERNETWORK LAYER (TCP/IP) 105
aspects of the connection in the hardware on the card. In most
cases, the data link layers are tuned to the limitations and require-
ments of their corresponding physical layers. So in real systems,
it is somewhat rare for a particular data link layer to be arbitrarily
paired with any number of physical layers. Since it can be hard
to separate the physical and data link aspects for a particular link
technology, the TCP model combines them into a single layer for
simplicity.
9.10 Internetwork Layer (TCP/IP)
One place that maps pretty cleanly between the two models is
the OSI Network and TCP/IP Internetwork layers. They perform
the same functions of creating a globally routable address space
and building routers to insure that packets properly find their way
from the source to the destination across multiple hops.
9.11 Transport Layer (TCP/IP)
The features of the Transport layer in TCP/IP are spread across the
Transport and Session layers of the OSI model. The OSI Transport
layer deals with flow control and packet retransmission, while the
OSI Presentation layer deals with multiple applications running on
multiple ports as well as session establishment and teardown.
The Secure Sockets Layer (SSL) in the TCP/IP model corresponds
to parts of the Session and Presentation layers in the OSI model.
9.12 Application Layer (TCP/IP)
The TCP/IP Application Layer combines the non-security aspects
of the OSI Presentation layer and the OSI Application layer. While
many TCP/IP applications deal with issues like encoding and de-
coding various types of data, the TCP/IP model does not see data
formatting as a separate “layer”. Various data encoding and de-
coding technologies are used in TCP/IP applications, but TCP/IP
tends to treat these capabilities as library code that applications
make use of as needed for the application.
106 CHAPTER 9. THE OSI MODEL
9.13 Conclusion
While the TCP/IP model described in this book is widely used to
guide the implementation of TCP/IP networks, hardware, and soft-
ware, the OSI model can help us look at and compare a wide
range of network architectures ranging from openly developed
networks to proprietary vendor-specific networks.
9.14 Glossary
abstract model: A model and set of terminology that is used to
generally understand a problem area and guide the development
of standards and implementations to solve problems.
implementation model: A model and set of terminology that is
used to guide the development of standards and an implementa-
tion to solve a particular problem.
ISO: International Organization for Standardization. A worldwide
body that develops standards in computing, networking, and
many other areas.
OSI: Open System Interconnection. A seven-layer model used to
help organize the design of various approaches to network archi-
tecture.
9.15 Questions
You can take this quiz online at http://www.net-intro.com/quiz/
1. What is the primary value of the OSI network model?
a) OSI networks are used in the southern hemisphere
b) The OSI approach can be use to analyze many different net-
work models
c) OSI networks make better use of limited bandwidth
d) OSI networks are more secure
2. How many layers does the OSI model have?
a) Four
9.15. QUESTIONS 107
b) Six
c) Seven
d) Nine
3. Which of the OSI layers deals with the shape of connectors
for network connections?
a) Physical
b) Data Link
c) Network
d) Transport
4. Which of the layers is most similar between the OSI and TCP
network models?
a) TCP Link Layer and OSI Data Link Layer
b) TCP Internetwork Layer and OSI Network Layer
c) TCP Transport Layer and OSI Transport Layer
d) TCP Application Layer and OSI Session Layer
5. What layer does the TCP/IP Secure Sockets Layer map to in
the OSI network model?
a) Secure Data Link Layer (SDLL)
b) Secure Network Layer (SNL)
c) Secure Transport Layer (STL)
d) Session and Presentation Layers
6. Why does the TCP model combine the OSI Data Link and
Physical layers into a single Link layer?
a) Because the TCP model does not worry about the Physical
layer
b) Because the TCP model designers were ignored at the 1981
OSI meeting in Utrect, Netherlands
c) Because quite often the design of Data Link and Physical
layers are tightly connected for a particular technology
d) To make the TCP model easier to understand by end users
108 CHAPTER 9. THE OSI MODEL
Chapter 10
Wrap Up
It has been said that building the Internet solved the world’s most
complex engineering problem to date. The design and engineer-
ing of the Internet started well over 50 years ago. It has been
continuously improving and evolving over the past 50 years and
will continue to evolve in the future.
The Internet now connects billions of computers using many thou-
sands of routers and link-level connections. The Internet is so
complex that it is never fully operational, The Internet is less
about being “perfect” and more about adapting to problems, out-
ages, errors, lost data, and many other unforeseen problems. The
Internet is designed to be flexible and adapt to whatever prob-
lems are encountered.
Transport
Application
Internetwork
Link
Figure 10.1: The Four-Layer Model
In order to build an overall solution that works at scale, it was
109
110 CHAPTER 10. WRAP UP
important to break the Internet engineering problems down into
four distinct layers:
• The Link/Physical layer includes all of the complex engineer-
ing required to move data across a single “hop”, whether the
hop is a wireless WiFi, wired Ethernet, fiber optic, or satellite
connection.
• The Internetwork Protocol (IP) layer is how data is routed
across a series of hops to get quickly and efficiently from one
of a billion source computers to any of a billion destination
computers. The IP layer dynamically adjusts and reroutes
data based on network load, link performance, or network
outages. While the IP layer is highly reliable and fast, at
times it loses or even throws away data. The IP layer is not
responsible for insuring the overall reliability of the network.
It just moves the data the best that it can.
• The Transport layer compensates for any imperfections in
the IP or Link layers. The Transport layer makes sure that
any lost packets are retransmitted and packets that arrive
out of order are put back into order before being passed on
to the receiving application. The Transport layer also acts as
flow control between the sending and receiving applications
to make sure that data is moved quickly when the network is
fast and the links are not overloaded, and to slow the trans-
fer of data when using slower or heavily loaded links. The
data flow and rate limitation in the Transport layer allow the
Internet to continue to function smoothly even when it is
heavily loaded.
• The other three layers make the use of the network very
simple for the Application Layer. An application can make a
network connection and send/receive data on that connec-
tion with just a few lines of code. By making the use of the
network simple, applications can focus on solving the end-
user problems they need to solve. Because it is so easy for
applications to use the network in new and different ways,
we have seen the emergence of a wide range of highly inno-
vative applications that work without any changes required
to the Internet protocols.
Without breaking the problem of engineering and building the In-
ternet into these four distinct layers, it would be far more difficult
to build and deploy ever-improving versions of the network. And
111
if every single application needed to be fully aware of all of the
complex details required to use the Internet, it would greatly limit
the richness and diversity of the networked applications that we
have today.
It is amazing to realize what has been accomplished in building
the Internet over the past 50 years. But in a way, we have only
just begun the engineering journey of building networked appli-
cations. It does not take much to imagine an Internet where ev-
ery light switch, lightbulb, refrigerator, table, automobile, road-
way, flying drone, and chair has an Internet address and they all
want to communicate with one another. New engineering issues
will have to be solved, and perhaps even the four-layer network
model will need to evolve to meet these new engineering chal-
lenges.
But just like brilliant engineers designed and evolved network pro-
tocols to move from hundreds of network-connected computers
to billions of network-connected computers, our present and fu-
ture engineers will certainly solve the problems and challenges
we will face as the network evolves to connect trillions of comput-
ers.
- Introduction
- Communicating at a Distance
- Computers Communicate Differently
- Early Wide Area Store-and-Forward Networks
- Packets and Routers
- Addressing and Packets
- Putting It All Together
- Glossary
- Questions
- Network Architecture
- The Link Layer
- The Internetwork Layer (IP)
- The Transport Layer (TCP)
- The Application Layer
- Stacking the Layers
- Glossary
- Questions
- Link Layer
- Sharing the Air
- Courtesy and Coordination
- Coordination in Other Link Layers
- Summary
- Glossary
- Questions
- Internetworking Layer (IP)
- Internet Protocol (IP) Addresses
- How Routers Determine the Routes
- When Things Get Worse and Better
- Determining Your Route
- Getting an IP Address
- A Different Kind of Address Reuse
- Global IP Address Allocation
- Summary
- Glossary
- Questions
- The Domain Name System
- Allocating Domain Names
- Reading Domain Names
- Summary
- Glossary
- Questions
- Transport Layer
- Packet Headers
- Packet Reassembly and Retransmission
- The Transport Layer In Operation
- Application Clients and Servers
- Server Applications and Ports
- Summary
- Glossary
- Questions
- Application Layer
- Client and Server Applications
- Application Layer Protocols
- Exploring the HTTP Protocol
- The IMAP Protocol for Retrieving Mail
- Flow Control
- Writing Networked Applications
- Summary
- Glossary
- Questions
- Secure Transport Layer
- Encrypting and Decrypting Data
- Two Kinds of Secrets
- Secure Sockets Layer (SSL)
- Encrypting Web Browser Traffic
- Certificates and Certificate Authorities
- Summary
- Glossary
- Questions
- The OSI Model
- Physical (Layer 1)
- Data Link (Layer 2)
- Network (Layer 3)
- Transport (Layer 4)
- Session (Layer 5)
- Presentation (Layer 6)
- Application (Layer 7)
- Comparing the OSI and TCP/IP Models
- Link Layer (TCP/IP)
- Internetwork Layer (TCP/IP)
- Transport Layer (TCP/IP)
- Application Layer (TCP/IP)
- Conclusion
- Glossary
- Questions
- Wrap Up
For the best experience, open this PDF portfolio in Acrobat X or Adobe Reader X, or later.
Get Adobe Reader Now!
1
3D Printing – Stage 1 Assignment
Kyami Clarke
IFSM 310 6980 Software and Hardware Infrastructure Concepts
University of Maryland Global Campus
Timothy Robinson
Summer 2021
2
3D Printing – Stage 1 Assignment
1. Background
Six years ago, Mark Peterson unknowingly took a hobby and began his journey into the
3D printing business. It all started with a purchase of a 3D printer for $500 and creating an
umbrella holder. A seedling of an idea germinated and subsequently grew to a whole business.
As the company began to produce a steady profit, Mark realized it was time to expand to
incorporate more employees, space, and equipment (i.e., software, hardware, applications). Due
to the increased business, he must monitor and facilitate operations (3D Printing Case Study,
n.d.).
The new infrastructure will revolve around Mark's 3D printing firm and building upon his
current setup. One 3D heavy-duty printer, two 3D wireless printing machines, one PC, and
Verizon FIOS with modem and wireless router. Mark will grow his firm and provide an
additional seven 3D printers. Together with his two present part-time staff, Mark will hire five
additional full-time staff. The company needs a 3D scanner and a document scanner. For Marks
training videos and 3D designs, and production data, cloud storage will be introduced together
with local storage. To keep track of orders, an ERP system is implemented. More systems will be
installed, and the access of all printers must be flexible. All staff must have mobile admittance to
the ERP and all 3D printers and enterprise files (3D Printing Case Study, n.d.).
The business expansion plan must include a stable infrastructure that meets his
requirements. The project needs to ensure that processes, procedures, and tools are necessary,
efficient, and the overhead for these expenses does not overshadow the profit. Mark's new IT
infrastructure should provide his organization with a way to manage his workforce and
operations locally and remotely. One of the critical elements is simplicity and consistency. This
3
will lead to consistency in your employee training and your product delivery. As a result, your
customer satisfaction will increase and provide cost savings as the business grows.
2. Current IT Infrastructure
Mark Peterson’s current IT infrastructure includes the following:
• Social Media
• One Wireless Heavy-Duty Printer
• Two Wireless 3D Printers
• Personal Computer
• Verizon FiOS Internet
• Verizon FiOS Modem with Built-in Wireless Router
• Google Gmail Account
• Microsoft Excel
• 3D Printing Design Software
3. Requirements
At some point, every successful small company beginning will have to deal with the
challenge of dealing with business expansion or growth. When a firm is growing, it is entering a
new phase of its existence ripe with both possibilities and risks. While business expansion
frequently results in a rise in financial fortunes for both owners and employees, on the other
hand, business development is not always accompanied by an increase in economic means
(Sadrzadehrafiei, Gholamzadeh Chofreh, Karimi Hosseini, & Sulaiman, 2013).
Implementing a sustainable and forward-thinking plan for scaling IT during a growth
phase may reduce stress in other departments while also saving the business money in the long
term. However, it is not easy to set aside time to deliberately prepare for the future of your
4
information technology systems when there are so many other variables that require your
attention right now.
The following five IT infrastructure requirements have been identified to support Mark’s plans to
expand his business:
1. Small Business Enterprise Resource Management (ERP)
2. Local Network Server Storage
3. Mobile Access - remote access to ERP, printers, and software (i.e., VPN)
4. Cloud Storage
5. Additional Equipment - Seven 3D Printers and One Multifunction Printer.
4. How are Requirements Met
Now that the necessary requirements have been identified, it is critical to establish how
Mark will implement these requirements. The essential requirement is the ERP, which will
address customer orders, payroll, invoicing, financial reporting, and data tracking. Mark will
need the correct network server to assist with the utilization of his ERP. As part of his expansion
plan, he will need the following items to meet the five requirements mentioned above.
• ERP Software –
o Oracle + NetSuite is a cost-effective and effective software solution for his
organization (Sadrzadehrafiei, Gholamzadeh Chofreh, Karimi Hosseini, &
Sulaiman, 2013). It provides business operation assistance and cloud-
based options, which would address three requirements simultaneously. It
is important not to overwhelm with too many varying software or
applications, leading to confusion and user error. It essential to keep the
process clean, efficient, and straightforward.
5
• Wireless Access Point (WAP) –
o Setting up a WAP network will ensure Mark and his team have wireless
access to his local network (LAN – Local Area Network). This means that
the IT infrastructure is interconnected locally and remotely and provides
Mark's mobility and flexibility to operate wherever needed. This is
especially important when an organization has multiple locations that need
to be connected or your customer service team is separate from your
manufacturing department.
• Multifunctional Printer (MFP) -
o The MFP will address scanning, faxing, and printing requirements.
However, the MFP needs to have remote access capabilities. Most MFP's
can be connected to the network server and can be used offsite if required.
Using an MFP will provide cost savings since you do not need to buy
separate scanners and printers since it will be all-in-one.
• Computer/Tablet -
o Employees who need to access ERP and 3D printing files and 3D printers
located across the facility would benefit from using Windows Surface
tablets and laptops. Mark had the option of selecting either the Surface 3
or the Surface Pro 4. According to Mark, these gadgets will allow
personnel to access relevant documentation and assist clients while
remaining mobile (Weill, Subramani, & Broadbent, 2002).
• Cloud Storage -
6
o Mark's 3D production files and business management information can be
saved locally on his existing PC, and he also has the option of adding an
external hard drive. It is recommended that in addition to storing backups
locally and on an external drive, Mark also keeps backups on the Cloud.
Microsoft Cloud storage is available for purchase by Mark. As a Cloud
storage solution, Microsoft OneDrive may be used, and any work done on
Surfaces can be stored to OneDrive and retrieved from there (OneDrive
QuickStart guide for small businesses, 2021).
5. Data Representation and Storage
The other component of his expansion is data and storage. This is a critical component
because the IT infrastructure must support and house multiple types of data. In addition, all the
equipment and software must be able to speak to each other. The following three data types
necessitate specific storage and computer requirements due to their varying formats and data
size.
a) Digital and Numerical Data - ERP
i. Binary coding is used to enter digital and numerical information into
computers. Binary code is a system of 1s and 0s that are used in computer
programming. Each of the numbers 1 or 0 represents a bit, and bits are the
smallest unit of data that a binary computer can understand (Severance, 2015).
The computer's interpretation of data is represented as digital data
representation. Instead of the letters or sentences that the computer user sees,
the computer understands the used coding systems. Consequently, Mark will
7
be able to see the letters he is saving, while the data stored on the computer is
binary code.
b) Audio Data – PC, Tablet, Cloud
i. Audio data is comprehended in segments, not in its entirety. With the use of
an input device such as a microphone, audio data can be recorded. Samples
are used in audio data. Examples are taken from the recording hundreds of
times per second, and when they are played back in the same sequence that
they were recorded, they will produce the original audio file captured. Files
are frequently compressed into formats such as MP3 to take up less space on a
computer's hard drive. This also makes songs easy to download or transfer and
save on an MP3 player or other portable media player (Introduction to
Computer Information Systems, 2016).
c) Video and Graphics Data – PC, Tablet, Cloud
i. Frames are used to record video data throughout the recording process. Video
is created by playing a series of frames, which are still shot several times each
second and then played back in succession. Video data contains a great deal of
information, and the files can be compressed to save storage space. It is
possible to store full-length movies, including thousands of frames on optical
discs, after being compressed using this method (Weill, Subramani, &
Broadbent, 2002).
ii. Graphics are multimedia data; these forms of data are images, and they can be
kept in the form of a bitmap image file, which is a bitmap image file is a
bitmap image file. A bitmap image is made up of pixels or a picture element
8
organized in a grid-like arrangement on a computer screen (Introduction to
Computer Information Systems, 2016). Color and intensity are represented by
specific groups of numbers in each pixel, and each pixel is made up of a
particular group of integers. Pixels are critical in determining the overall
quality of an image. An image with a large number of pixels will almost
certainly be of higher quality.
9
References
3D Printing Case Study. (n.d.). Retrieved June 20, 2021, from University of Maryland Global
Campus: https://learn.umgc.edu/d2l/le/content/581305/viewContent/21821578/View
Introduction to Computer Information Systems. (2016). Wikibooks. Retrieved June 28, 2021,
from https://learn.umgc.edu/d2l/le/content/581305/viewContent/21821575/View
OneDrive QuickStart guide for small businesses. (2021, April 22). Retrieved June 29, 2021, from
Microsoft: https://docs.microsoft.com/en-us/onedrive/one-drive-quickstart-small-business
Sadrzadehrafiei, S., Gholamzadeh Chofreh, A., Karimi Hosseini, N., & Sulaiman, R. (2013). The
Benefits of Enterprise Resource Planning (ERP) System Implementation in Dry Food
Packaging Industry. Procedia Technology, 11, 220-226.
doi:https://doi.org/10.1016/j.protcy.2013.12.184
Severance, C. (2015). Introduction to Networking. (S. Blumenberg, Ed.) CreateSpace. Retrieved
June 28, 2021, from http://creativecommons.org/licenses/by-nc/4.0
Weill, P., Subramani, M., & Broadbent, M. (2002, October 15). Building IT Infrastructure for
Strategic Agility. Retrieved June 29, 2021, from MIT Sloan Management Review:
https://sloanreview.mit.edu/article/building-it-infrastructure-for-strategic-agility/
- 3D Printing – Stage 1 Assignment
- 3D Printing – Stage 1 Assignment
- 1. Background
- 2. Current IT Infrastructure
- 3. Requirements
- 4. How are Requirements Met
- 5. Data Representation and Storage
- References
7/14/2021 Feedback for Stage 1 - IFSM 310 6980 Software and Hardware Infrastructure Concepts (2215) - UMGC Learning Management System
https://learn.umgc.edu/d2l/lms/dropbox/user/folder_user_view_feedback.d2l?db=1112310&grpid=0&isprv=0&bp=0&ou=581305 1/5
Feedback for Stage 1
Submission Feedback
Overall Feedback
Rubric Name: Stage 1
Stage 1
84 / 100
Score
12.6 / 15 - 84 %
Feedback Date
Jul 13, 2021 7:52 PM
Assignment
IFSM 310 6980 Software and Hardware Infrastructur…
Assignments View Feedback
Good job on the Stage 1 Requirement Background and Current Infrastructure – requirement met Five Requirements – provided, good job – requirements met How requirements will be met – good job on describing and detailing out I would recommend identifying specific associated costs and names for all devices/services as if you were Mark himself since costs are a concern to all small business owners – good job on identifying the name of some recommended services and/or devices Data representation and storage – could be more in-depth as to where some of these files/data will be stored Digital, Audio, Video, Graphics – missing graphic extensions – such as, .jpeg References of two or more – requirement met Format – perfect Feel free to contact me if you have any questions. Thanks, Tim
Done
7/14/2021 Feedback for Stage 1 - IFSM 310 6980 Software and Hardware Infrastructure Concepts (2215) - UMGC Learning Management System
https://learn.umgc.edu/d2l/lms/dropbox/user/folder_user_view_feedback.d2l?db=1112310&grpid=0&isprv=0&bp=0&ou=581305 2/5
Stage 1
Submission ID Submission(s) Date Submitted
11820469 Clarke_Kyami_Stage_1.docx (23.25 KB) Jul 6, 2021 9:28 AM
7/14/2021 Feedback for Stage 1 - IFSM 310 6980 Software and Hardware Infrastructure Concepts (2215) - UMGC Learning Management System
https://learn.umgc.edu/d2l/lms/dropbox/user/folder_user_view_feedback.d2l?db=1112310&grpid=0&isprv=0&bp=0&ou=581305 3/5
7/14/2021 Feedback for Stage 1 - IFSM 310 6980 Software and Hardware Infrastructure Concepts (2215) - UMGC Learning Management System
https://learn.umgc.edu/d2l/lms/dropbox/user/folder_user_view_feedback.d2l?db=1112310&grpid=0&isprv=0&bp=0&ou=581305 4/5
7/14/2021 Feedback for Stage 1 - IFSM 310 6980 Software and Hardware Infrastructure Concepts (2215) - UMGC Learning Management System
https://learn.umgc.edu/d2l/lms/dropbox/user/folder_user_view_feedback.d2l?db=1112310&grpid=0&isprv=0&bp=0&ou=581305 5/5
5
3D Printing – Stage 2 Assignment
Kyami Clarke
IFSM 310 6980 Software and Hardware Infrastructure Concepts
University of Maryland Global Campus
Timothy Robinson
Summer 2021
3D Printing – Stage 2 Assignment
Background
Mark has analyzed the Phase 1 suggestions and details and has requested that you tell him what elements he will require to support his "Expansion Plan." Mark would like to concentrate on substituting his worksheet of customer demands with a small-scale business ERP information management in his warehouse to assist him in maintaining his business successfully.
Components for 3D Printing System
Software is divided into two parts: Design and Printer integration.
Designing tools
1. Ultimate Cura software creates your model for 3d printers and includes a plug for laptop design tools.
2. Blender is a well-known computer-aided design program (CAD). Although this powerful design software is not suitable for beginners, it is easier to use by the availability of community support and a free software framework.
Hardware Components
1. Various heavy-duty multi-output abilities 3D printers that include metal, carbon, and nylon. Exone Corporation specializes in custom-built industrial and mid-build 3D printing.
2. Mark's 3D printing layouts and documents are stored on a Lenovo ThinkServer TS140 server with a monitor.
3. The MS Surface Pro 6 tablet gives the development team more flexibility by allowing them to move about the office.
4. The Verizon Fios Quantum Gateway, with speeds of 300/300 Mbps, is the all modems and routers that enable wireless mobile internet access.
5. The Linksys Velop Intelligent Mesh WiFi System (3) will increase the range of the wireless signals.
6. Wireless serial number scanner used to deliver inventory data to tracking software.
Components for ERP Infrastructure
Local business enterprise resource management (ERP) management software will include mostly these features, such as accounting, sales, and payment processing.
1. Dynamics 365 Business Core Elements is a simple-to-use and modify all-in-one business administration tool. Velosio, a global network partner, will handle the setup, installation, and maintenance.
2. Microsoft Windows 10, the basic OS on which the Microsoft Surface Pro’s will be loaded.
3. Microsoft Office 365 is a set of word processors and presentation software that the operational and administrative teams will use.
4. Bitdefender Antivirus Plus is a premium antivirus program that is reliable, affordable and includes privacy features.
5. Users will have the option of paying with PayPal or using a credit/debit card through PaySafe via Bitdefender.
Hardware components will be the same as used for the 3D production process above:
1. All of Mark's 3D printing layouts and documents are stored on a Lenovo ThinkServer TS140 server with the monitor.
2. The MS Surface Pro 6 tablet gives the development team more flexibility by allowing them to move about the office.
3. Xerox C505 for Multifunctional printer with mobile printing functionalities.
Overall System Working
Mark began 3D printing as a pastime. He's discovered his calling and plans to expand his 3D printing ability. To do so, he'll need to be familiar with the commercial side of 3D printing. He's into a good start by paying for new heavy-duty printers that acquire their files and folders from WiFi tablets. As Mark invests in mesh WiFi technology, backboned by Verizon Fios optical fiber service, these tablets allow Mark's production staff to work from wherever in the warehouses. The tablets are bundled with advanced CAD software to aid artists in creating new layouts or modifications to existing customer's designs.
Mark must also keep track of the materials he is using or what is remaining in his stock. Marks' online business includes implementing inventory software using Microsoft Dynamics 365 Business Core Basics and wirelessly hand-held scanners.
As a result, it's critical that both the 3D printing and administrative processes operate in tandem; otherwise Mark's aspirations for a profitable business will remain only that hope and nothing more.
Graphical Representation of Hardware Components
Graphical Representation of Software Components
References
3D Printing Case Study. (n.d.). Retrieved June 20, 2021, from University of Maryland Global Campus: https://learn.umgc.edu/d2l/le/content/581305/viewContent/21821578/View
Everything's faster with the new Fios Router. Verizon. (n.d.). https://fios.verizon.com/fios-routers.html
Introduction to Computer Information Systems. (2016). Wikibooks. Retrieved June 28, 2021, from https://learn.umgc.edu/d2l/le/content/581305/viewContent/21821575/View
Institute, B. (n.d.). Blender for 3D Printing. Blender Cloud. https://cloud.blender.org/p/3d-printing
Tims, Morelia, John, Hitemharder, Better, E., Rlmarti, Jocamel, & All, I. T. T. (2017, January 11). Linksys Velop Intelligent Mesh WiFi System, Tri-Band, 3-Pack White (AC6600). Linksys. https://www.linksys.com/us/p/P-WHW0303/
Surface Pro 7 – Ultra-light and versatile – Microsoft Surface. Microsoft Store. (n.d.). https://www.microsoft.com/en-us/p/surfacepro-6/8zcnc665slq5?activetab=pivot%3Aoverviewtab
Ultimaker Cura: Powerful, easy-to-use 3D printing software. ultimaker.com. (n.d.). https://ultimaker.com/en/products/ultimaker-cura-software
5
3D Printing – Stage 1 Assignment
Kyami Clarke
IFSM 310 6980 Software and Hardware Infrastructure Concepts
University of Maryland Global Campus
Timothy Robinson
Summer 2021
3D Printing – Stage 1 Assignment
1. Background
Six years ago, Mark Peterson unknowingly took a hobby and began his journey into the 3D printing business. It all started with a purchase of a 3D printer for $500 and creating an umbrella holder. A seedling of an idea germinated and subsequently grew to a whole business. As the company began to produce a steady profit, Mark realized it was time to expand to incorporate more employees, space, and equipment (i.e., software, hardware, applications). Due to the increased business, he must monitor and facilitate operations (3D Printing Case Study, n.d.).
The new infrastructure will revolve around Mark's 3D printing firm and building upon his current setup. One 3D heavy-duty printer, two 3D wireless printing machines, one PC, and Verizon FIOS with modem and wireless router. Mark will grow his firm and provide an additional seven 3D printers. Together with his two present part-time staff, Mark will hire five additional full-time staff. The company needs a 3D scanner and a document scanner. For Marks training videos and 3D designs, and production data, cloud storage will be introduced together with local storage. To keep track of orders, an ERP system is implemented. More systems will be installed, and the access of all printers must be flexible. All staff must have mobile admittance to the ERP and all 3D printers and enterprise files (3D Printing Case Study, n.d.).
The business expansion plan must include a stable infrastructure that meets his requirements. The project needs to ensure that processes, procedures, and tools are necessary, efficient, and the overhead for these expenses does not overshadow the profit. Mark's new IT infrastructure should provide his organization with a way to manage his workforce and operations locally and remotely. One of the critical elements is simplicity and consistency. This will lead to consistency in your employee training and your product delivery. As a result, your customer satisfaction will increase and provide cost savings as the business grows.
2. Current IT Infrastructure
Mark Peterson’s current IT infrastructure includes the following:
· Social Media
· One Wireless Heavy-Duty Printer
· Two Wireless 3D Printers
· Personal Computer
· Verizon FiOS Internet
· Verizon FiOS Modem with Built-in Wireless Router
· Google Gmail Account
· Microsoft Excel
· 3D Printing Design Software
3. Requirements
At some point, every successful small company beginning will have to deal with the challenge of dealing with business expansion or growth. When a firm is growing, it is entering a new phase of its existence ripe with both possibilities and risks. While business expansion frequently results in a rise in financial fortunes for both owners and employees, on the other hand, business development is not always accompanied by an increase in economic means (Sadrzadehrafiei, Gholamzadeh Chofreh, Karimi Hosseini, & Sulaiman, 2013).
Implementing a sustainable and forward-thinking plan for scaling IT during a growth phase may reduce stress in other departments while also saving the business money in the long term. However, it is not easy to set aside time to deliberately prepare for the future of your information technology systems when there are so many other variables that require your attention right now.
The following five IT infrastructure requirements have been identified to support Mark’s plans to expand his business:
1. Small Business Enterprise Resource Management (ERP)
2. Local Network Server Storage
3. Mobile Access - remote access to ERP, printers, and software (i.e., VPN)
4. Cloud Storage
5. Additional Equipment - Seven 3D Printers and One Multifunction Printer.
4. How are Requirements Met
Now that the necessary requirements have been identified, it is critical to establish how Mark will implement these requirements. The essential requirement is the ERP, which will address customer orders, payroll, invoicing, financial reporting, and data tracking. Mark will need the correct network server to assist with the utilization of his ERP. As part of his expansion plan, he will need the following items to meet the five requirements mentioned above.
· ERP Software –
· Oracle + NetSuite is a cost-effective and effective software solution for his organization (Sadrzadehrafiei, Gholamzadeh Chofreh, Karimi Hosseini, & Sulaiman, 2013). It provides business operation assistance and cloud-based options, which would address three requirements simultaneously. It is important not to overwhelm with too many varying software or applications, leading to confusion and user error. It essential to keep the process clean, efficient, and straightforward.
· Wireless Access Point (WAP) –
· Setting up a WAP network will ensure Mark and his team have wireless access to his local network (LAN – Local Area Network). This means that the IT infrastructure is interconnected locally and remotely and provides Mark's mobility and flexibility to operate wherever needed. This is especially important when an organization has multiple locations that need to be connected or your customer service team is separate from your manufacturing department.
· Multifunctional Printer (MFP) -
· The MFP will address scanning, faxing, and printing requirements. However, the MFP needs to have remote access capabilities. Most MFP's can be connected to the network server and can be used offsite if required. Using an MFP will provide cost savings since you do not need to buy separate scanners and printers since it will be all-in-one.
· Computer/Tablet -
· Employees who need to access ERP and 3D printing files and 3D printers located across the facility would benefit from using Windows Surface tablets and laptops. Mark had the option of selecting either the Surface 3 or the Surface Pro 4. According to Mark, these gadgets will allow personnel to access relevant documentation and assist clients while remaining mobile (Weill, Subramani, & Broadbent, 2002).
· Cloud Storage -
· Mark's 3D production files and business management information can be saved locally on his existing PC, and he also has the option of adding an external hard drive. It is recommended that in addition to storing backups locally and on an external drive, Mark also keeps backups on the Cloud. Microsoft Cloud storage is available for purchase by Mark. As a Cloud storage solution, Microsoft OneDrive may be used, and any work done on Surfaces can be stored to OneDrive and retrieved from there (OneDrive QuickStart guide for small businesses, 2021).
5. Data Representation and Storage
The other component of his expansion is data and storage. This is a critical component because the IT infrastructure must support and house multiple types of data. In addition, all the equipment and software must be able to speak to each other. The following three data types necessitate specific storage and computer requirements due to their varying formats and data size.
a) Digital and Numerical Data - ERP
i. Binary coding is used to enter digital and numerical information into computers. Binary code is a system of 1s and 0s that are used in computer programming. Each of the numbers 1 or 0 represents a bit, and bits are the smallest unit of data that a binary computer can understand (Severance, 2015). The computer's interpretation of data is represented as digital data representation. Instead of the letters or sentences that the computer user sees, the computer understands the used coding systems. Consequently, Mark will be able to see the letters he is saving, while the data stored on the computer is binary code.
b) Audio Data – PC, Tablet, Cloud
i. Audio data is comprehended in segments, not in its entirety. With the use of an input device such as a microphone, audio data can be recorded. Samples are used in audio data. Examples are taken from the recording hundreds of times per second, and when they are played back in the same sequence that they were recorded, they will produce the original audio file captured. Files are frequently compressed into formats such as MP3 to take up less space on a computer's hard drive. This also makes songs easy to download or transfer and save on an MP3 player or other portable media player (Introduction to Computer Information Systems, 2016).
c) Video and Graphics Data – PC, Tablet, Cloud
i. Frames are used to record video data throughout the recording process. Video is created by playing a series of frames, which are still shot several times each second and then played back in succession. Video data contains a great deal of information, and the files can be compressed to save storage space. It is possible to store full-length movies, including thousands of frames on optical discs, after being compressed using this method (Weill, Subramani, & Broadbent, 2002).
ii. Graphics are multimedia data; these forms of data are images, and they can be kept in the form of a bitmap image file, which is a bitmap image file is a bitmap image file. A bitmap image is made up of pixels or a picture element organized in a grid-like arrangement on a computer screen (Introduction to Computer Information Systems, 2016). Color and intensity are represented by specific groups of numbers in each pixel, and each pixel is made up of a particular group of integers. Pixels are critical in determining the overall quality of an image. An image with a large number of pixels will almost certainly be of higher quality.
References 3D Printing Case Study. (n.d.). Retrieved June 20, 2021, from University of Maryland Global Campus: https://learn.umgc.edu/d2l/le/content/581305/viewContent/21821578/View Introduction to Computer Information Systems. (2016). Wikibooks. Retrieved June 28, 2021, from https://learn.umgc.edu/d2l/le/content/581305/viewContent/21821575/View OneDrive QuickStart guide for small businesses. (2021, April 22). Retrieved June 29, 2021, from Microsoft: https://docs.microsoft.com/en-us/onedrive/one-drive-quickstart-small-business Sadrzadehrafiei, S., Gholamzadeh Chofreh, A., Karimi Hosseini, N., & Sulaiman, R. (2013). The Benefits of Enterprise Resource Planning (ERP) System Implementation in Dry Food Packaging Industry. Procedia Technology, 11, 220-226. doi:https://doi.org/10.1016/j.protcy.2013.12.184 Severance, C. (2015). Introduction to Networking. (S. Blumenberg, Ed.) CreateSpace. Retrieved June 28, 2021, from http://creativecommons.org/licenses/by-nc/4.0 Weill, P., Subramani, M., & Broadbent, M. (2002, October 15). Building IT Infrastructure for Strategic Agility. Retrieved June 29, 2021, from MIT Sloan Management Review: https://sloanreview.mit.edu/article/building-it-infrastructure-for-strategic-agility/
��������� ����� �� ����� ����������������������� �� ��� ���� ��� ����� � ���� �������� � ���!���"#���$�%��&� ��'���� � ��(�����)���(
*�� �+��,� ��-�(� -������,�,(����� ��.������ �,���/����/0'��/ ���� �-��,1��2�������3�� '�2�3'� �02�3� 2�3��2"����" ���
4556789:;<=>;?@8A5;B
CDEFGHHGIJKLMMNEOPQ
RSMTOUUKLMMNEOPQ
VDETGPKWOFMXKCYOZMK[
; ?@8A5;B
\];̂;_̀`
CPITM
_]ab;̂;B̀;c;\];d
LMMNEOPQKeOYM
fgh;B]i;B̀B_;\j_\;kl
mHHGZJFMJY
?@8A5;B
n4?l;o_̀;pq\̀;?=<@r8>5;8s6;t8>6r8>5;ns<>8u@>g9@g>5;v=s95w@u;xBB_yz
{uu|As}5s@u ;~|5r;4556789:
��8}|i �==6;�=7;=s;@�5;?@8A5;B;�=}5r=>:;8uu|As}5s@a �|u@;8s6;65u9>|75;@�5;9=}w=s5s@u;x�8>6r8>5i;u=<@r8>5i;u59g>|@�;65�|95ui;s5@r=>: 65�|95ui;r|>56̂r|>5h5uu;65�|95ui;|s@5>s5@i;8s6;68@878u5ui;8u;8ww>=w>|8@5z;s55656;<=> @�5;9=}wg@5>;u�u@5}xuz;@=;75;gu56;@=;9>58@5;@�5;o�;w>|s@56;|@5}ua;;;�;>59=}}5s6 |65s@|<�|sA;@�5;}8:5û}=65hu;8s6;8uu=9|8@56;w>|95u;u=;l8>:;98s;@8:5;@�|u;|s@= 9=su|65>8@|=s;8s6;8s�;8uu=9|8@56;u5>�|95;<55u;c;u=}5;|65s@|<|56 �|u@;8s6;65u9>|75;@�5;9=}w=s5s@u;x�8>6r8>5i;u=<@r8>5i;u59g>|@�;65�|95ui;s5@r=>: 65�|95ui;r|>56̂r|>5h5uu;65�|95ui;|s@5>s5@i;8s6;68@878u5ui;8u;8ww>=w>|8@5z;l8>:;r|hh s556;@=;|}wh5}5s@;8;u}8hh;7gu|s5uu;5s@5>w>|u5;>5u=g>95;}8s8A5}5s@;x��kz |s<=>}8@|=s;u�u@5};|s;�|u;<89|h|@�;@=;�5hw;�|};}8s8A5;�|u;7gu|s5uu;5<<59@|�5h�a;?=}5 =<;@�5u5;r|hh;75;@�5;u8}5;8u;u=}5;9=}w=s5s@u;h|u@56;<=>;@�5;o�;u�u@5}a;�;��k u=hg@|=s;r|hh;866>5uu;@�5;68@878u5;>5�g|>5}5s@;gs65>;@�|u;u59@|=s ��wh8|s;@�5;>5h8@|=su�|wu;8}=sA;@�5;o�;9=}wg@5>;u�u@5}i;@�5;|s<=>}8@|=s;u�u@5}i 8s6;@�5;9=}}gs|98@|=s;s5@r=>:u;@�8@;ugww=>@;7=@�;@�w5u;=<;u�u@5}u;8s6;�=r;@�5� <|@;@=A5@�5>;@=;w>=�|65;l8>:;8hh;@�5;n�;98w87|h|@�;�5;s556u;@=;>gs;�|u;7gu|s5uua;� A==6;�=7 �>8w�|98h;�5w>5u5s@8@|=s;x<>=};w8>@;_z;�;5�95hh5s@;6|8A>8} 4=>}8@;�>5�g|>5}5s@;}5@ 455h;<>55;@=;9=s@89@;}5;|<;�=g;�8�5;8s�;�g5u@|=sua ��8s:ui
?g7}|uu|=s;n� ?g7}|uu|=sxuz �8@5;?g7}|@@56
__\qy\pB vh8>:5���8}|�?@8A5�Ba6=9�;xby\ayB;��z fgh;_qi;B̀B_;\j̀o;kl;
eIJM
��������� ����� �� ����� ����������������������� �� ��� ���� ��� ����� � ���� �������� � ���!���"#���$�%��&� ��'���� � ��(�����)���(
*�� �+��,� ��-�(� -������,�,(����� ��.������ �,���/����/0'��/ ���� �-��,1��2�������3�� '�2�3'� �02�3� 2�3��2"����" ���
��������� ����� �� ����� ����������������������� �� ��� ���� ��� ����� � ���� �������� � ���!���"#���$�%��&� ��'���� � ��(�����)���(
*�� �+��,� ��-�(� -������,�,(����� ��.������ �,���/����/0'��/ ���� �-��,1��2�������3�� '�2�3'� �02�3� 2�3��2"����" ���
Stage 3 Course: IFSM 310 6980 Software and Hardware Infrastructure Concepts (2215)
/ 20
Criteria Far Above Standards
Above Standards
Meets Standards
Below Standards
Well Below Standards
Criterion Score
Component
s for New
(remote)
Locations
20 points
18-20 Points List of
components
for the new
(remote)
locations
includes all
appropriate
hardware,
software,
security
devices,
network
devices,
wired/wireless
devices,
internet, and
databases and
demonstrates
sophisticated
level of
analysis and
critical
thinking.
17 points
16-17 Points List of
components
for the new
(remote)
locations
includes most
of the
necessary
hardware,
software,
security
devices,
network
devices,
wired/wireless
devices,
internet, and
databases, and
demonstrates
analysis and
critical
thinking.
15 points
14-15 Points List of
components
for the new
(remote)
locations
including
hardware,
software,
security
devices,
network
devices,
wired/wireless
devices,
internet, and
databases is
provided and
demonstrates
adequate level
of analysis and
critical
thinking.
13 points
12-13 Points List of
components
for the new
(remote)
locations is
incomplete or
not related to
Case Study.
0 points
0-11 Points List of
components
for the new
(remote)
locations is
not included,
or is very
incomplete or
incorrect. Paragraph
Lato (Recom…
19px
/ 20
/ 20
Criteria Far Above Standards
Above Standards
Meets Standards
Below Standards
Well Below Standards
Criterion Score
Changes in
Existing IT
Infrastructur
e
Explanation
of
Differences
between
Main
Location
and Remote
Locations
20 points
18-20 Points Explanation of
changes in
existing
infrastructure
to
accommodate
the new
locations is
clear,
complete,
derived from
the Case
Study, and
demonstrates
sophisticated
level of
analysis and
critical
thinking.
17 points
16-17 Points Explanation of
changes in
existing
infrastructure
to
accommodate
the new
locations is
accurate,
derived from
the Case
Study, and
demonstrates
analysis and
critical
thinking.
15 points
14-15 Points Explanation of
changes in
existing
infrastructure
to
accommodate
the new
locations is
derived from
the Case
Study, and
demonstrates
adequate level
of analysis and
critical
thinking.
13 points
12-13 Points Explanation of
changes in
existing
infrastructure
to
accommodate
the new
locations is
incomplete or
not related to
Case Study.
0 points
0-11 Points Explanation of
changes in
existing
infrastructure
to
accommodate
the new
locations is
not included,
or is very
incomplete or
incorrect.
20 points
18-20 Points Explanation of
the
differences
between the
IT at the main
location and at
the remote
locations is
clear,
complete,
derived from
the Case
Study, and
demonstrates
sophisticated
level of
analysis and
critical
thinking.
17 points
16-17 Points Explanation of
the
differences
between the
IT at the main
location and at
the remote
locations is
clear, derived
from the Case
Study, and
demonstrates
analysis and
critical
thinking.
15 points
14-15 Points Explanation of
the
differences
between the
IT at the main
location and at
the remote
locations is
derived from
the Case
Study, and
demonstrates
adequate level
of analysis and
critical
thinking.
13 points
12-13 Points Explanation of
the
differences
between the
IT at the main
location and at
the remote
sites is
incomplete or
not related to
the Case
Study.
0 points
0-11 Points Explanation of
the
differences
between the
IT at the main
location and at
the remote
locations is
not included,
or is very
incomplete or
incorrect.
/ 30
/ 10
Criteria Far Above Standards
Above Standards
Meets Standards
Below Standards
Well Below Standards
Criterion Score
Graphical
Representati
on
Format
30 points
27-30 Points The graphical
diagram is
complete,
clear, logical,
labeled, and
appropriate to
the Case
Study,
includes the
components
listed in Part
1, and
demonstrates
sophisticated
analysis and
critical
thinking.
26 points
24-26 Points The graphical
diagram is
clear, logical,
labeled,
appropriate to
the Case
Study and
includes
Explanation
includes the
components
listed in Part
1, and
demonstrates
a clear
understanding
of the course
concepts.
23 points
21-23 Points The graphical
diagram is
labeled and is
appropriate to
the Case
Study and
includes most
of the
components
listed in Part
1.
20 points
18-20 Points The graphical
diagram may
be lacking in
completeness
and/or clarity
and/or logic;
may not be
labeled or
appropriate to
the Case
Study and may
not include
the
components
listed in Part
1.
0 points
0-17 Points No graphical
diagram is
included, or
minimal effort
demonstrated.
10 points
9-10 Points Submission
reflects
effective
organization
and
sophisticated
writing;
follows
instructions
provided; uses
correct
structure,
grammar, and
spelling;
presented in a
professional
format using
Word.
8.5 points
8.5 Points Submission
reflects
effective
organization
and clear
writing;
follows
instructions
provided; uses
correct
structure,
grammar, and
spelling;
presented in a
professional
format using
Word.
7.5 points
7.5 Points Submission is
adequate, is
somewhat
organized,
follows
instructions
provided; cont
ains minimal
grammar
and/or spelling
errors; is in
Word format.
6.5 points
6.5 Points Submission is
not well
organized,
and/or does
not follow
instructions
provided;
and/or
contains
grammar
and/or spelling
errors; and/or
is not in Word.
0 points
0-5 Points Document is
extremely
poorly written
and does not
convey the
information.
Total / 100
Overall Score
Far Above
Standards 90 points minimum
Above
Standards 80 points
minimum
Meets
Standards 70 points
minimum
Below
Standards 60 points
minimum
Well Below
Standards 0 points minimum
3D Printing Stage 3 1
IFSM 310 3D Printing Stage 3 Assignment
Before you begin this assignment, be sure you: • Have completed all previously assigned readings. • Read the “3D Printing Case Study." • Reviewed the feedback on your 3D Printing Stage 1 and Stage 2 Assignments.
It is several months later and Mark has implemented your recommendations for his IT infrastructure. Business is booming! Mark's father has seen what a great success Mark's 3D printing business is, and he wants to provide the capital to open two more facilities near Veterans Administration Hospitals in Memphis, Tennessee and Phoenix, Arizona. Mark is very excited about expanding his business and being located near service men and women who will benefit from his 3D printed accessibility and assistive devices. Since he has already purchased several server and storage devices to hold his designs and business information, he would like to retain that investment. One thing he has learned is that, with very high speed internet connections, the 3D design files can be downloaded in just a few seconds, so they would not have to be stored at each of his new locations. Mark's plan is to create two new facilities, each with the same number of 3D printers and staff as he has at his current location. The employees at the new locations will also need access to the ERP system to report their time and order supplies, etc.
Mark has asked you to explain how his IT infrastructure should be changed to accommodate these two new facilities and allow him to manage the overall enterprise as one business. Use the following outline for your paper:
1. List the components. In part 1 of your Stage 2 assignment, you listed the computer system, information system, and network components needed at Mark's facility. Here you will list which of those components (hardware, software, security devices, communication network and its devices, wired/wireless devices, internet, and data and information, as appropriate) will be located at each of the two new (remote) locations. (Create one list; it will be the same for both.) Some components may not be needed at the new locations; you should not list those. The new locations may require some components not in use at the original site; these should be included in the list.
2. Explain the changes that will be needed in Mark's current (existing) IT infrastructure to incorporate the two new locations, and handle the increase in the number of designs and orders and the additional employees.
3. Explain what is different in the IT infrastructure at the two new locations versus the IT infrastructure now in place at Mark's current facility, and explain why the differences exist.
4. Create an original graphical representation of the three facilities and show the devices that would be located at each location. Show how the locations would be connected and the devices required.
Formatting: • Parts 1, 2, and 3 should be about 2 single spaced pages in length, and be in Microsoft Word format,
or a format that can be read in Word.
3D Printing Stage 3 2
• Part 4 is an original graphic diagram(s) that should be included in the same document. If you have too much difficulty inserting the diagram, you may provide it as a separate file that can be read by Word, Excel or PowerPoint.
• Compare your work to the Grading Rubric below to be sure you have met content and quality criteria.
• Your submission should include your last name first in the filename: Lastname_firstname_Stage_3
GRADING RUBRIC: The "right" and "wrong" answers have to do with whether or not you correctly incorporated the course vocabulary and concepts from the textbook to support your choices and have addressed all parts of the assignment.
3D Printing Stage 3 3
Criteria
90-100%
Far Above Standards
80-89%
Above Standards
70-79%
Meets Standards
60-69%
Below Standards
< 60%
Well Below Standards
Possible Points
Components for New (remote) Locations
18-20 Points
List of components for the new (remote) locations includes all appropriate hardware, software, security devices, network devices, wired/wireless devices, internet, and databases and demonstrates sophisticated level of analysis and critical thinking.
16-17 Points
List of components for the new (remote) locations includes most of the necessary hardware, software, security devices, network devices, wired/wireless devices, internet, and databases, and demonstrates analysis and critical thinking.
14-15 Points
List of components for the new (remote) locations including hardware, software, security devices, network devices, wired/wireless devices, internet, and databases is provided and demonstrates adequate level of analysis and critical thinking.
12-13 Points
List of components for the new (remote) locations is incomplete or not related to Case Study.
0-11 Points
List of components for the new (remote) locations is not included, or is very incomplete or incorrect.
20
Changes in Existing IT Infrastructure
18-20 Points
Explanation of changes in existing infrastructure to accommodate the new locations is clear, complete, derived from the Case Study, and demonstrates sophisticated level of analysis and critical thinking.
16-17 Points
Explanation of changes in existing infrastructure to accommodate the new locations is accurate, derived from the Case Study, and demonstrates analysis and critical thinking.
14-15 Points
Explanation of changes in existing infrastructure to accommodate the new locations is derived from the Case Study, and demonstrates adequate level of analysis and critical thinking.
12-13 Points
Explanation of changes in existing infrastructure to accommodate the new locations is incomplete or not related to Case Study.
0-11 Points
Explanation of changes in existing infrastructure to accommodate the new locations is not included, or is very incomplete or incorrect.
20
Explanation of Differences between Main Location and Remote Locations
18-20 Points
Explanation of the differences between the IT at the main location and at the remote locations is clear, complete, derived from the Case Study, and demonstrates sophisticated level of analysis and critical thinking.
16-17 Points
Explanation of the differences between the IT at the main location and at the remote locations is clear, derived from the Case Study, and demonstrates analysis and critical thinking.
14-15 Points
Explanation of the differences between the IT at the main location and at the remote locations is derived from the Case Study, and demonstrates adequate level of analysis and critical thinking.
12-13 Points
Explanation of the differences between the IT at the main location and at the remote sites is incomplete or not related to the Case Study.
0-11 Points
Explanation of the differences between the IT at the main location and at the remote locations is not included, or is very incomplete or incorrect.
20
3D Printing Stage 3 4
Graphical Representa- tion
27-30 Points
The graphical diagram is complete, clear, logical, labeled, and appropriate to the Case Study, includes the components listed in Part 1, and demonstrates sophisticated analysis and critical thinking.
24-26 Points
The graphical diagram is clear, logical, labeled, appropriate to the Case Study and includes Explanation includes the components listed in Part 1, and demonstrates a clear understanding of the course concepts.
21-23 Points
The graphical diagram is labeled and is appropriate to the Case Study and includes most of the components listed in Part 1.
.
18-20 Points
The graphical diagram may be lacking in completeness and/or clarity and/or logic; may not be labeled or appropriate to the Case Study and may not include the components listed in Part 1.
0-17 Points
No graphical diagram is included, or minimal effort demonstrated.
30
Format 9-10 Points
Submission reflects effective organization and sophisticated writing; follows instructions provided; uses correct structure, grammar, and spelling; presented in a professional format using Word.
8.5 Points
Submission reflects effective organization and clear writing; follows instructions provided; uses correct structure, grammar, and spelling; presented in a professional format using Word.
7.5 Points
Submission is adequate, is somewhat organized, follows instructions provided; contains minimal grammar and/or spelling errors; is in Word format.
6.5 Points
Submission is not well organized, and/or does not follow instructions provided; and/or contains grammar and/or spelling errors; and/or is not in Word.
0-5 Points
Document is extremely poorly written and does not convey the information.
10
TOTAL Points Possible
100
- TOTAL Points Possible
3D Printing Case Study
In late 2015, Mark Peterson acquired a 3D printer from Best Buy for $500. As he began to play around with it, he discovered that he could use designs he downloaded from the Internet to create a wide variety of objects. One day as he was exploring designs on the website MyMiniFactory.com (https://www.myminifactory.com/), he came across a category of accessibility items. He was very excited to discover such things as an umbrella holder for a wheelchair, because his brother Peter uses a wheelchair for mobility. He downloaded the umbrella holder design and made one for Peter. The first time Peter used the umbrella holder, several people came up and asked him where he had gotten it. Of course, he was proud to say his brother had made it, but he had no idea how much it would cost for Mark to make one for a customer. Peter took the names and phone numbers of two people he encountered and promised to get back to them. When Peter approached Mark with the requests, Mark knew that he had found the start of something good. He figured out what the time and material cost would be to make the holders, called the interested parties, and made his first two sales.
As he continued exploring, Mark ran across an article describing ten 3D printable assistive and accessibility devices (https://3dprint.com/126214/103dp-devices-for-the-disabled/). After investing in a heavy duty 3D printer, Mark used his Facebook page to advertise his growing business in 3D printing assistive and accessibility devices. He soon had many orders and his 3D printing hobby became his fulltime occupation.
Mark rented space in an industrial park, bought two more wireless 3D printers, and hired two part-time assistants. He brought his PC from home to control the 3D printers, and set up an Internet connection using Verizon FiOS. His PC is connected to a FiOS modem which has a built-in wireless router. Mark obtains his 3D printing designs from sources on the internet. He uses Google email and keeps track of his orders on a spreadsheet on his PC.
Your assignment, which will be done in four stages, is to assist Mark in understanding what kind of infrastructure he needs; how it would be configured; how it will change when his business grows into a much larger, multi-location operation; and how the various devices communicate with each other. Specific instructions for each of the four staged assignments may be found under the Assignments tab.
3D Printing Case Study – IFSM 310 10/28/2016

Get help from top-rated tutors in any subject.
Efficiently complete your homework and academic assignments by getting help from the experts at homeworkarchive.com