New Perspectives Computer Concepts 2013 Comprehensive. 15th brief edition by Cengage

Computer Concepts 2013

COMPREHENSIVE • 1 5 T H B RI E F E D I T I O N Parsons :: Oja

Computer Concepts 2013

COMPREHENSIVE • 1 5 T H B RI E F E D I T I O N Parsons :: Oja

New Perspectives. Computer Concepts 2013. Comprehensive, 15th Brief Edition June Jamrich Parsons y Dan Oja Presidente de Cengage Learning Latinoamérica Fernando Valenzuela Migoya Director editorial, de producción y de plataformas digitales para Latinoamérica Ricardo H. Rodríguez Gerente de procesos para Latinoamérica Claudia Islas Licona Gerente de manufactura para Latinoamérica Raúl D. Zendejas Espejel Gerente editorial de contenidos en español Pilar Hernández Santamarina Coordinador de manufactura Rafael Pérez González

© D.R. 2012 por Cengage Learning Editores, S.A. de C.V., una compañía de Cengage Learning, Inc. Corporativo Santa Fe Av. Santa Fe núm. 505, piso 12 Col. Cruz Manca, Santa Fe C.P. 05349, México, D.F. Cengage Learning® es una marca registrada usada bajo permiso. DERECHOS RESERVADOS. Ninguna parte de este trabajo amparado por la Ley Federal del Derecho de Autor podrá ser reproducida, transmitida, almacenada o utilizada en cualquier forma o por cualquier medio, ya sea gráfico, electrónico o mecánico, incluyendo, pero sin limitarse a lo siguiente: fotocopiado, reproducción, escaneo, digitalización, grabación en audio, distribución en Internet, distribución en redes de información o almacenamiento y recopilación en sistemas de información, a excepción de lo permitido en el Capítulo III, Artículo 27 de la Ley Federal del Derecho de Autor, sin el consentimiento por escrito de la editorial.

Editoras Ivonne Arciniega Torres Gloria Luz Olguín Sarmiento

Adaptado del libro New Perspectives on Computer Concepts 2013. Comprehensive

Diseño de portada Roycroft Design

Imagen de portada © Masterfile Adaptación de interiores Gerardo Larios

Datos para catalogación bibliográfica: Parsons, June Jamrich y Dan Oja New Perspectives. Computer Concepts 2013. Comprehensive, 15th Brief Edition ISBN: 978-607-481-402-6 Visite nuestro sitio en: http://latinoamerica.cengage.com

Impreso en México 1 2 3 4 5 6 7 15 14 13 12

iii

TABL E OF CO NT E N T S

CO NTE N T S A T A G L A NCE ORIENTATION

176 New Perspectives Labs

O-2 Orientation

177 Key Terms

O-4 Section A: Getting Started

180 Key Terms

O-14 Section B: Documents, Browsers, and E-mail O-22 Section C: Security and Privacy

CHAPTER 1

CHAPTER 4 182 Local Area Networks 184 Section A: Network Building Blocks

2 Computers and Digital Basics

194 Section B: Wired and Wireless Technologies

4 Section A: All Things Digital

203 Section C: Network Setup

14 Section B: Digital Devices

213 Section D: Sharing Files

22 Section C: Digital Data Representation

220 Section E: Wireless Security

29 Section D: Digital Processing

226 Issue: Who’s Tracking You?

34 Section E: Password Security

228 Information Tools: Wikipedia

42 Issue: What Is the Value of Information?

230 Technology in Context: Education

44 Information Tools: Finding the Right Stuff

232 New Perspectives Labs

46 Technology in Context: Marketing

233 Key Terms

48 New Perspectives Labs 49 Key Terms

CHAPTER 2

CHAPTER 5 238 The Internet 240 Section A: Internet Technology

54 Computer Hardware

250 Section B: Fixed Internet Access

56 Section A: Personal Computer Basics

259 Section C: Portable and Mobile Internet Access

67 Section B: Microprocessors and Memory

267 Section D: Internet Services

76 Section C: Storage Devices

277 Section E: Internet Security

88 Section D: Input and Output Devices

284 Issue: What’s a Revolution Without

98 Section E: Hardware Security 106 Issue: Where Does All the Ewaste Go? 108 Information Tools: Making the Cut 110 Technology in Context: Military 112 New Perspectives Labs 113 Key Terms

CHAPTER 3 118 Software 120 Section A: Software Basics 132 Section B: Office Suites 143 Section C: Installing Software

and Upgrades

the Internet? 286 Information Tools: Citations 288 Technology in Context: Banking 290 New Perspectives Labs 291 Key Terms

CHAPTER 6 296 The Web and E-mail 298 Section A: Web Technology 312 Section B: Search Engines 322 Section C: E-commerce 330 Section D: E-mail 338 Section E: Web and E-mail Security

154 Section D: Buying Software

346 Issue: Who’s Reading Your E-mail?

162 Section E: Security Software

348 Information Tools: Your Own Words

170 Issue: How Serious Is Software Piracy?

350 Technology in Context: Fashion Industry

172 Information Tools: Organizing Your Writing

352 New Perspectives Labs

174 Technology in Context: Journalism

353 Key Terms

C O NT EN T S A T A GLA NCE

CHAPTER 7 358 Digital Media 360 Section A: Digital Sound 368 Section B: Bitmap Graphics 382 Section C: Vector and 3-D Graphics 390 Section D: Digital Video 402 Section E: Digital Rights Management 410 Issue: What Happened to Fair Use? 412 Information Tools: Media Attribution 414 Technology in Context: Film 416 New Perspectives Labs 417 Key Terms

422

GLOSSARY

440

INDEX

TABL E OF CO NT E N T S

SEC T I O N A, C H APT ER 12

TABLE O F C O N T E N T S

ORIENTATION

O-30 Safe Social Networking O-31 Online Privacy and Safety Guidelines

O-4 Section A: Getting Started

O-31 QuickCheck C

O-4 Computer Equipment O-5 How to Turn Your Computer On and Off O-6 Windows Basics O-7 Mac OS X Basics O-8 Mouse Basics O-9 Keyboard Basics O-10 Working with Windows Software O-12 Working with Mac Software O-13 Help O-13 QuickCheck A O-14 Section B: Documents, Browsers, and

E-mail O-14 Creating Documents O-16 Internet and Web Basics O-16 How to Use a Web Browser and

Search Engine O-19 Working with E-mail O-21 QuickCheck B O-22 Section C: Security and Privacy O-22 Securing Your Digital Devices and Data O-23 Avoiding Viruses O-24 Preventing Intrusions O-25 Blocking Spyware and Pop-up Ads O-26 Protecting E-commerce Transactions O-27 Avoiding E-mail Scams O-29 Protecting Your Privacy

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T A B LE O F C O N T ENTS

CHAPTER 1

COMPUTERS AND DIGITAL BASICS

22 Section C: Digital Data Representation 22 Data Representation Basics 23 Representing Numbers, Text, Images,

and Sound 26 Quantifying Bits and Bytes

4 Section A: All Things Digital

27 Circuits and Chips

4 The Digital Revolution

28 QuickCheck C

6 Data Processing 7 Personal Computing 8 Network Computing 9 Cloud Computing 10 Digital Society 13 QuickCheck A 14 Section B: Digital Devices 14 Computer Basics 16 Computer Types and Uses 20 Microcontrollers 21 QuickCheck B

29 Section D: Digital Processing 29 Programs and Instruction Sets 31 Processor Logic 33 QuickCheck D 34 Section E: Password Security 34 Authentication Protocols 36 Password Hacks 38 Secure Passwords 41 QuickCheck E 42 Issue: What Is the Value of Information? 44 Information Tools: Finding the Right Stuff 46 Technology in Context: Marketing 48 New Perspectives Labs

Oleksiy Mark /Shutterstock.com

49 Key Terms 50 Summary 52 Situation Questions 53 Learning Objectives Checkpoints

and Concept Map

vii

TABL E OF CO NT E N T S

CHAPTER 2

COMPUTER HARDWARE

76 Section C: Storage Devices 76 Storage Basics 78 Magnetic Storage Technology 81 Optical Storage Technology

56 Section A: Personal Computer Basics

84 Solid State Storage Technology

56 Personal Computer Systems

86 Storage Wrap–up

58 Desktop and Portable Computers

87 QuickCheck C

60 Home, Game, and Small Business Systems 62 Buying a Computer

65 Handheld Computers 66 QuickCheck A

88 Section D: Input and Output Devices 88 Basic Input Devices 90 Display Devices 92 Printers

67 Section B: Microprocessors and Memory

94 Installing Peripheral Devices

67 Microprocessor Basics

97 QuickCheck D

71 Today’s Microprocessors 72 Random Access Memory 74 Read-Only Memory 74 EEPROM 75 QuickCheck B

98 Section E: Hardware Security 98 Anti-Theft Devices 99 Surge Protection and Battery Backup 101 Basic Maintenance 103 Troubleshooting and Repair

Alexander Kalina/Shutterstock.com

105 QuickCheck E 106 Issue: Where Does All the E-waste Go? 108 Information Tools: Making the Cut 110 Technology in Context: Military 112 New Perspectives Labs 113 114 116 117

Key Terms Summary Situation Questions Learning Objectives Checkpoints and Concept Map

viii

T A B LE O F C O NT EN TS

CHAPTER 3

174 Technology in Context: Journalism

SOFTWARE

176 New Perspectives Labs

120 Section A: Software Basics 120 Software Categories 121 Music Software 122 Video Software

177 178 180 180 181

Key Terms Summary Key Terms Situation Questions Learning Objectives Checkpoints and Concept Map

123 Graphics Software 125 Mapping and Location-based Software 126 Business and “Number Crunching” Software 127 Desktop Publishing Software almagami /Shutterstock.com

128 Personal Finance Software 129 Utility Software 131 Device Drivers 131 QuickCheck A 132 Section B: Office Suites 132 Office Suite Basics 133 Word Processing 136 Spreadsheets 139 Databases 142 Presentations 142 QuickCheck B 143 Section C: Installing Software and

CHAPTER 4

LOCAL AREA NETWORKS

Upgrades 143 Web Apps

184 Section A: Network Building Blocks

145 Mobile Apps

184 Network Classifications

146 Local Applications

186 LAN Advantages and Disadvantages

151 Portable Software

188 Network Devices

152 Software Upgrades and Updates

189 Network Links

153 Uninstalling Software

190 Communications Protocols

153 QuickCheck C

193 QuickCheck A

154 Section D: Buying Software

194 Section B: Wired and Wireless

154 Consumer Basics

Technologies

156 Software Copyrights and Licenses

194 Wired Basics

161 QuickCheck D

195 Ethernet 197 Wireless Basics

162 Section E: Security Software

199 Bluetooth

162 Security Software Basics

200 Wi-Fi

166 Security Suites

202 QuickCheck B

167 Antivirus Modules 169 QuickCheck E

203 Section C: Network Setup 203 Setup Overview

170 Issue: How Serious Is Software Piracy? 172 Information Tools: Organizing Your

Writing

204 Router Installation 206 Router Configuration 210 Internet Connection

TABL E OF CO NT E N T S

211 Device connection 212 QuickCheck C

247 Connection Speed 249 QuickCheck A

213 Section D: Sharing Files 213 File Sharing Basics

250 Section B: Fixed Internet Access

214 Accessing Shared Files

250 Dial-up Connections

215 Sharing Your Files

252 DSL

217 File Servers

254 Cable Internet Service

218 Network Troubleshooting

256 Satellite Internet Service

219 QuickCheck D

257 Fixed Wireless Service 258 Fixed Internet Connection Roundup

220 Section E: Wireless Security

258 QuickCheck B

220 Wi-Fi Security 223 Encryption 225 QuickCheck E

259 Section C: Portable and Mobile Internet

Access 259 Internet to Go

226 Issue: Whoâ&#x20AC;&#x2122;s Tracking You? 228 Information Tools: Wikipedia 230 Technology in Context: Education

260 Wi-Fi Hotspots 262 Portable and Mobile WiMAX 262 Portable Satellite Service 263 Cellular Data Service 266 QuickCheck C

232 New Perspectives Labs 233 234 236 237

Key Terms Summary Situation Questions Learning Objectives Checkpoints and Concept Map

267 Section D: Internet Services 267 Cloud Computing 269 Real-Time Messaging 269 Voice Over IP 270 Forums, Wikis, Blogs, and Tweets 272 Grid Computing 273 FTP 275 File Sharing Networks

CHAPTER 5

THE INTERNET

276 QuickCheck D 277 Section E: Internet Security 277 Intrusion Attempts 279 Securing Ports

240 Section A: Internet Technology

280 NAT

240 Background

283 Virtual Private Networks

241 Internet Infrastructure

283 QuickCheck E

243 Internet Protocols, Addresses, and Domains

T A B LE O F C O N T ENTS

284 Issue: What’s a Revolution Without the

338 Section E: Web and E-mail Security

Internet?

338 Cookie Exploits 342 Spam

286 Information tools: Citations

343 Phishing 344 Fake Sites

288 Technology in Context: Banking

345 QuickCheck E 290 New Perspectives Labs 291 292 294 295

346 Issue: Who’s Reading Your E-mail?

Key Terms Summary Situation Questions Learning Objectives Checkpoints and Concept Map

348 Information Tools: Your Own Words 350 Technology in Context: Fashion Industry 352 New Perspectives Labs 353 Key Terms

CHAPTER 6

354 Summary 356 Situation Questions 357 Learning Objectives Checkpoints

THE WEB AND E-MAIL

and Concept Map 298 Section A: Web Technology

300 HTML 302 HTTP 304 Web Browsers 306 Cookies 307 Web Page Authoring 309 HTML Scripts

Alexander Kalina/Shutterstock.com

298 Web Basics

311 QuickCheck A 312 Section B: Search Engines 312 Search Engine Basics 316 Formulating Searches 320 Using Web-Based Source Material

CHAPTER 7

321 QuickCheck B 322 Section C: E-commerce

DIGITAL MEDIA

322 E-commerce Basics 324 E-commerce Site Technology

360 Section A: Digital Sound

327 Online Payment

360 Digital Audio Basics

329 QuickCheck C

363 Digital Audio File Formats 365 MIDI Music

330 Section D: E-mail

366 Speech Recognition and Synthesis

330 E-mail Overview

367 QuickCheck A

332 Local E-mail 334 Webmail

368 Section B: Bitmap Graphics

336 E-mail Attachments

368 Bitmap Basics

337 Netiquette

370 Scanners and Cameras

337 QuickCheck D

372 Image Resolution 375 Color Depth and Palettes

TABL E OF CO NT E N T S

378 Image Compression

406 Music DRM

381 QuickCheck B

407 Movie DRM 408 eBook DRM

382 Section C: Vector and 3-D Graphics 382 Vector Graphics Basics

408 Enforcement 409 QuickCheck E

385 Vector-to-Bitmap Conversion 386 Vector Graphics on the Web

410 Issue: What Happened to Fair Use?

387 3-D Graphics 389 QuickCheck C 390 Section D: Digital Video 390 Digital Video Basics 391 Producing Video Footage

412 Information Tools: Media Attribution 414 Technology in Context: Film 416 New Perspectives Labs 417 418 420 421

Key Terms Summary Situation Questions Learning Objectives Checkpoints and Concept Map

399 DVD-Video

422

401 QuickCheck D

440

GLOSSARY INDEX

393 Video Transfer 394 Video Editing 395 Video Output 397 Web Video

402 Section E: Digital Rights Management 402 Content Basics 404 DRM Technologies

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NEW PERSPECTIVES LABS CHAPTER 1 Operating a Personal Computer Working with Binary Numbers

CHAPTER 2 Benchmarking

CHAPTER 3 Installing and Uninstalling Software

CHAPTER 4 Local Area Networks

CHAPTER 5 Tracking Packets Securing Your Connection

CHAPTER 6 Browser Security & Privacy Working with Cookies Working with HTML

CHAPTER 7

Africa Studio/Shutterstock.com

Working with Bitmap Graphics

T A B LE O F C O N T ENTS

NEW PERSPECTIVES

Computer Concepts 2013

COMPREHENSIVE • 1 5 T H BRI E F E D I T I O N Parsons :: Oja

Chapter Contents

SECTION A: ALL THINGS DIGITAL The Digital Revolution Data Processing Personal Computing Network Computing Cloud Computing Digital Society SECTION B: DIGITAL DEVICES Computer Basics Computer Types and Uses Microcontrollers SECTION C: DIGITAL DATA REPRESENTATION Data Representation Basics Representing Numbers, Text, Images, and Sound Quantifying Bits and Bytes Circuits and Chips SECTION D: DIGITAL PROCESSING Programs and Instruction Sets Processor Logic SECTION E: PASSWORD SECURITY Authentication Protocols Password Hacks Secure Passwords ISSUE: WHAT IS THE VALUE OF INFORMATION? INFORMATION TOOLS: FINDING THE RIGHT STUFF TECHNOLOGY IN CONTEXT: MARKETING NEW PERSPECTIVES LABS

Computers and Digital Basics Learning Objectives After reading this chapter, you will be able to answer the following questions by completing the outcomes-based Learning Objectives Checkpoints on page 53. 1. What are the four phases of the digital revolution? 2. What is convergence and how does it apply to the digital revolution? 3. In what ways does digital technology affect society? 4. How do computers work with input, output, processing, storage, and stored programs? 5. What’s the difference between an operating system and application software? 6. How do personal computers differ from servers, mainframes, and supercomputers? 7. Are portable media players and mobile phones classified as computers? 8. Why are microcontrollers the computers no one sees? 9. Aren’t data and information the same thing? 10. What’s the difference between analog and digital? 11. How do digital devices use 1s and 0s to work with numbers, text, images, and sound? 12. Why is there so much jargon pertaining to bits and bytes? 13. What hardware components manipulate the bits that represent data? 14. Why do computers need programs? 15. How do a microprocessor’s ALU and control unit work? 16. How do hackers steal passwords? 17. How can I create secure passwords?

INFOWEBLINKS You’ll find updates for chapter material by connecting to the NP2013 Chapter 1 InfoWebLink. CLICK TO CONNECT www.infoweblinks.com/np2013/ch01

COMPUTERS AND DIGITAL BASICS

Apply Your Knowledge The information in this chapter will give you the background to: t Inventory the digital devices you own t Put digital technology in the context of history, pop culture, and the global economy t Read computer ads with an understanding of technical terminology

t Select secure passwords for protecting your computer and Internet logins t Use a password manager to keep track of all your passwords t Use digital devices with an awareness of how they might infringe on your privacy

Try It! WHATâ&#x20AC;&#x2122;S MY DIGITAL PROFILE? The average American consumer owns more than 24 digital devices. Before you begin Chapter 1, take an inventory of your digital equipment to find the brands, models, and serial numbers. Tuck this information in a safe place. It can come in handy when you need to call technical support, arrange for repair services, or report missing equipment. 1. Onto your computer copy the following table ble for any digital equipment you own, rent, lease, e, or use and fill in the blanks.

Brand

Model

Serial Number

Computer Keyboard Mouse Monitor Printer Digital camera Digital music player Internet or network device Mobile phone Game console Other (list)

Data Processing

Freedom and Democracy

Digital Revolution

Personal Computing

Network Computing

Cloud Computing

Digital Society

Economy

Privacy

Intellectual Property

All Things Digital SECTION

WE LIVE IN THE INFORMATION AGE: a period in history when information is easy to access and affects many aspects of everyday life, from the economy to politics and social relationships. The importance of information is not new. It has always been a powerful tool. Scrolls treasured by monks during the Middle Ages, scientific knowledge collected during the Renaissance, and intelligence data collected during the Cold War were all critical in shaping world events. The Information Age is unique because of its underlying technology based on digital electronics. Section A offers an overview of the digital revolution that ushered in the Information Age.

TERMINOLOGY NOTE The word digital comes from the root digit. In Latin, the word digitus means finger or toe. The modern use of the term digital is probably derived from the idea of counting on your fingers.

THE DIGITAL REVOLUTION What is the digital revolution? The digital revolution is an ongoing process of social, political, and economic change brought about by digital technology, such as computers and the Internet. Like the agricultural and industrial revolutions, the digital revolution offers advantages, but requires adaptations. Digital innovations challenge the status quo and require societies to make adjustments to traditions, lifestyles, and legislation.

FIGURE 1-1

The digital revolution has a profound effect on everyday life.

Velora/Shutterstock.com, Steve Bower/Shutterstock.com, Ivan Bondarenko/Shutterstock.com, © MediaTechnics

The technology driving the digital revolution is based on digital electronics and the idea that electrical signals can represent data, such as numbers, words, pictures, and music. Without digital electronics, computers would be huge machines, priced far beyond the reach of individuals; your favorite form of entertainment would probably be foosball, and you’d be listening to bulky vacuum tube radios instead of carrying sleek iPods (Figure 1-1).

CO MPUTERS AND DIG IT AL B AS IC S

What is the significance of digitization? Digitization is the process of converting text, numbers, sound, photos, and video into data that can be processed by digital devices. The significant advantage of digitization is that things as diverse as books, movies, songs, conversations, documents, and photos can all be distilled down to a common set of signals that do not require separate devices. Before digitization, a phone conversation required a telephone handset and dedicated phone lines. Viewing photos required a slide projector and screen. Reading required a paper book. Viewing movies required a film projector. Once digitized, however, conversations, photos, books, and movies can all be managed by a single device or transmitted over a single set of communication lines.

You can pull a photo down from a Web site, store it on your computer’s hard disk, make a copy of it on a flash drive, send it to a friend as an e-mail attachment, add it to a report, print it, combine it with other photos to make a slide show, burn the slide show to a CD, and watch the slide show on your home theater system. You can use a digitized photo in so many ways. In contrast, if you just have a photo print, you can make a copy of it with a photo copier, send it by snail mail, or frame it, but not much else. Digitization creates versatility.

FIGURE 1-2

The digital revolution has evolved through four phases, beginning with big, expensive, standalone computers, and progressing to today’s digital world in which small, inexpensive digital devices are everywhere (Figure 1-2).

As the digital revolution progressed, technology changed, as did the way we used it.

Expired

Tired

Uninspired

Desired

Data processing

Personal computing

Network computing

Cloud computing

Big corporate and government computers

Desktop computers

Notebook computers

iPhone, Droid X, and iPadlike devices

Custom applications

Standalone applications

Monolithic software suites

Handheld apps and cloudbased apps

CB radios

Dial-up Internet access

Cable, satellite Internet access

3G, Wi-Fi Internet access

ARPANET

AOL and CompuServe

The Web and virtual worlds

Social media

Arcade games

2-D action games

3-D multiplayer games

Touch screen microgames for handheld devices

S EC T I O N A , C H A P T ER 1

DATA PROCESSING When did the digital revolution begin? Some historians mark the 1980s as the beginning of the digital revolution, but engineers built the first digital computers during World War II for breaking codes and calculating missile trajectories. In the 1950s, computers were marketed for business applications, such as payroll and inventory management.

What was computing like back then? In this first phase of the digital revolution, computers were huge, complex, and expensive devices. They existed in limited numbers, primarily housed in big corporations and government agencies. Computers were operated by trained specialists. Each computer installation required specialized software. The idea that computers might be used by ordinary people in their homes was only a glimmer of an idea in the minds of science fiction writers.

FIGURE 1-3

In the 1950s and 1960s, data used by government and business computers was coded onto punched cards that contained the warning “Do not fold, tear, or mutilate this card.” Similar slogans were used by protesters who were concerned that computers would have a dehumanizing effect on society.

Back then, processing components for computers were housed in closetsized cabinets that did not usually include a keyboard or display device. Computers were accessed using the keyboard and display screen of a terminal. Terminals had little processing capability of their own, so they were simply used to enter data and view results produced by software that ran on the main computer. During the antiestablishment era of the 1960s, the digital revolution was beginning to transform organizations, but ordinary people had little direct contact with computers. As with many new technologies, computers were initially viewed with suspicion by consumers, who were uncomfortable with the idea of giant machine “brains.” Computers seemed remote. They were housed out of sight in special facilities and were inaccessible to ordinary people. Computers also seemed impersonal. Instead of names, computers used Social Security numbers to uniquely identify people (Figure 1-3). Throughout the first phase of the digital revolution, businesses adopted computers with increasing enthusiasm as benefits for cutting costs and managing mountains of data became apparent. Computers and data processing became crucial tools for effective business operations.

Input

Process

FIGURE 1-4

Feng Yu /Shutterstock.com

ep_stock /Shutterstock.com

Michael D Brown /Shutterstock.com

What is data processing? Data processing is based on an inputprocessing-output cycle. Data goes into a computer, it is processed, and then it is output. For example, a batch of employee time cards are entered into a payroll computer system; the payroll data is processed to calculate take-home pay, deductions, and taxes; paychecks are output (Figure 1-4).

Output

Data processing is the computing model for the first phase of the digital revolution. The concept of large computers performing tasks based on the input-processing-output cycle represents the primary way computers were used from the 1940s through the 1970s. Data processing installations still exist today, but other technologies emerged, making computing available to a more diverse group of users.

CO MPUTERS AND DIG IT AL B AS IC S

PERSONAL COMPUTING When did digital devices become available to consumers? Digital devices were first available to consumers in the 1970s when handheld calculators and digital watches hit store shelves. The first personal computers made their debut in 1976, but sales got off to a slow start. Without compelling software applications, personal computers, such as the Apple II, seemed to offer little for their $2,400 price.

As the variety of software increased, however, consumer interest grew. In 1982, TIME magazine’s Man of the Year award went to the computer, an indication that these digital machines had finally gained a measure of popular acceptance.

What is personal computing? The model for the second phase of the digital revolution, personal computing is characterized by small, standalone computers powered by local software. Local software refers to any software that is installed on a computer’s hard drive. During this phase of the digital revolution, computers were not connected to networks, so they were essentially self-contained units that allowed users to interact with installed software. On the business front, large computers continued to run payroll, inventory, and financial software. Some managers used personal computers and spreadsheet software to crunch numbers for business planning. If you owned a computer back in the second phase of the digital revolution, it was probably a small standalone machine with a display device that looked like an old-fashioned television (Figure 1-5). FIGURE 1-5

Courtesy of Blake Patterson

The most popular uses for personal computers were word processing and gaming; sound systems and graphics capabilities were primitive. The Internet wasn’t open to public use, so computing was not a social experience.

How long was the second phase of the digital revolution? In 1982, computers had gained recognition in TIME magazine, but fewer than 10% of U.S. households had a computer. Working on a standalone computer wasn’t for everyone. People without an interest in typing up corporate reports or school papers, crunching numbers for accounting, or playing computer games weren’t tempted to become active soldiers in the digital revolution. Social scientists even worried that people would become increasingly isolated as they focused on computer activities rather than social ones. Computer ownership increased at a gradual pace until the mid-1990s, and then it suddenly accelerated into the third phase of the digital revolution.

S EC T I O N A , C H A P T ER 1

NETWORK COMPUTING What caused the sudden upswing in computer ownership during the 1990s? The third phase of the digital revolution materialized as computers became networked and when the Internet was opened to public use. A computer network is a group of computers linked together to share data and resources. Network technology existed before the Internet became popular, but those networks were mainly deployed to connect computers within a school or business. Networks were complicated to set up and unreliable. As the third phase of the digital revolution unfolded, network technology became consumer-friendly, allowing homeowners to connect multiple computers, exchange files, and, most importantly, share an Internet connection. The Internet is a global computer network originally developed as a military project, and was then handed over to the National Science Foundation for research and academic use. When restrictions on commercial use of the Internet were lifted in 1995, companies such as AOL and CompuServe became popular services for access to e-mail and the World Wide Web. Internet access was a major factor contributing to the upswing in computer ownership during the 1990s.

What about the Web? When historians look back on the digital revolution, they are certain to identify the Web as a major transformative influence. The Web (short for World Wide Web) is a collection of linked documents, graphics, and sounds that can be accessed over the Internet. A key aspect of the Web is that it adds content and substance to the Internet. Without the Web, the Internet would be like a library without any books or a railroad without any trains. Online storefronts, auction sites, news, sports, travel reservations, and music downloads made the Web a compelling digital technology for just about everyone.

So what was computing like? During the period from 1995–2010, computing was characterized by the Web, e-mail, multiplayer games, music downloads, and enormous software applications, such as Microsoft Office, Norton’s Internet Security Suite, and Corel Digital Studio (Figure 1-6).

Computers included multimedia equipment for music and video. Computers stored most data locally on the hard disk or flash drives. Application software was typically stored locally.

FIGURE 1-6

Computers were the primary devices for accessing the Internet prior to 2010, but applications, media, and data remained on the local hard disk.

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ail

Internet connections provided access to e-mail and the Web.

CO MPUTERS AND DIG IT AL B AS IC S

CLOUD COMPUTING Is the Web dead? A 2010 Wired magazine cover announced “The Web is Dead.” That pronouncement was premature, but Facebook, Twitter, and Google Apps have sent computing in new directions. Local applications are being eclipsed by cloud computing, which characterizes the fourth phase of the digital revolution. What is cloud computing? Cloud computing provides access to

FIGURE 1-7

information, applications, communications, and storage over the Internet. Before cloud computing, your computer typically ran software based locally. For example, to use a word processor, you might fire up the latest edition of Microsoft Word, which you’d installed on your computer’s hard disk. Prior to the cloud, you stored data locally, too. E-mail, documents, photos, and music all resided on your computer’s hard disk or flash drive.

The “cloud” represents Internetbased services, such as applications and social media, that are available from computers and handheld digital devices.

With cloud computing, all that changes. You can use your browser to access word processing applications that run from the Internet, instead of software that you have installed on your local hard disk. You can use online applications to manage your e-mail, create floor plans, produce presentations, and carry out a host of other activities. You can store your data in the cloud, too, making it available no matter what computer you’re using as long as it has an Internet connection.

Social networking Searching

Web-mail

C LOUD C OMPUTING Apps

e-Commerce

Data file storage

The cloud gets its name from diagrams like the one in Figure 1-7 that show Internet-based applications, storage, and other services outlined by a cloud-like shape designed to help you visualize the idea that cloud services are “out there” somewhere on the Internet.

What is convergence? The expansion of cloud computing is due in part to convergence, a process by which several technologies with distinct functionalities evolve to form a single product. Your computer plays movies. Your cell phone has a camera. Your clock has a radio. Your watch functions as a compass. You can store data on your iPod touch. All these are examples of technological convergence. Convergence worked its magic on cell phones, computers, portable media players, digital cameras, GPSs, watches, and e-book readers. Now you get features from all of them by purchasing a single digital device. Whether you purchase a full-size computer, a sophisticated mobile phone, or even a game console, you typically have access to software, music, photos, ebooks, movies, communications, and the Web (Figure 1-8).

FIGURE 1-8

High-end mobile phones such as the iPhone and Droid X offer a huge selection of applications and Internet access.

Convergence is important to the digital revolution because it created sophisticated mobile devices whose owners demand access to the same services available from full-size computers on their desks. Your smartphone isn’t usually in range of the cable modem in your house, so it needs a different way to access the Internet. Your iPad is too small for a huge hard disk, so it needs an alternative place to store data and applications. You can see how these mobile devices require a solution such as cloud computing to provide a full spectrum of digital services.

In 2010, the average consumer owned more than 24 digital devices. With convergence on a roll, you can expect that number to dwindle, as consumers discover the versatility of today’s multipurpose digital devices.

S EC T I O N A , C H A P T ER 1

What role do social media play? The fourth phase of the digital revolution turned the worry of social isolation on its head; instead of computers decreasing human interaction, social media encourage interpersonal communications and relationships. Social media are cloud-based applications designed for social interaction and consumer-generated content. They include social networking services, wikis, blogging services, photo sharing services, and microblogging sites (Figure 1-9). Sociiall nettwo So ork rki kin ing ing services: i

Face Fa ceb book bo k Goog Goog gle+ le+ Link inkedI kedI dIn n

FIGURE 1-9

Social media include many popular services.

Medi Medi Me dia a sh shar har ariin ing: ing:

Wiki Wi kis:

Flickr Photobucket YouTube e Metaca Met taca acaffe fe Vi Vime meo eo o

Wikip Wiki Wi kipe ki pedi pe dia di a W Wiki ikim ik imed im edia ed dia ia

Blogging Blog Bl og ggi g ng gs services: ervi er vice vi ces: ce s:

M crob Micr Mi obl bllo b logg logg ggiin ing ing: g::

WordPress W ordPress Googl Google g e Blogg Blogger ggerr Type Ty p Pa Pad

Twit Twit itte itt ter T ter Tu umbl um br blr bl

Myspace, Facebook, and Twitter became some of the first popular social networking services. Myspace lost steam in 2008, but Facebook and Twitter marched ahead. By 2011, Facebook had 750 million users and Twitter had 200 million. Many factors influenced the popularity of these sites, but one important factor is their ease of use. As cloud-based services, there is no software to install and there are no updates to worry about. Getting started is as simple as registering your name and creating a password.

How is today’s computing different from the past? Using computers during the fourth phase of the digital revolution, you’re likely to have a mobile device that accesses the Internet using a cell phone service provider. The touch screen on your mobile device gives you access to apps that play music, show movies, report news and sports scores, help you find the nearest Starbucks, and all kinds of other fun stuff. You occasionally use Google or Wikipedia to access information; and when you need to produce a document, you head over to Google to access its cloud-based word processor. You spend lots of time maintaining your profiles on social networking services and interacting with friends through cloud-based social media.

DIGITAL SOCIETY How does digital technology affect freedom and democracy? Freedom of speech is the cornerstone of democracy. It can be defined as being able to speak freely without censorship or fear of reprisal. The concept is not limited to speaking, but includes all forms of expression, including writing, art, and symbolic actions. The more inclusive term freedom of expression is sometimes used instead of freedom of speech. Freedom of speech is not an absolute. Most societies prohibit or repress some types of expression, such as hate speech, libel, pornography, and flag burning. Although freedom of expression is guaranteed under the U.S. Constitution, the European Convention on Human Rights, and the Universal Declaration of Human Rights, these documents recognize the necessity for some restrictions, which might vary from one society to the next. Incidents ranging from the controversy over teaching evolution in schools to the Arab world’s fury over cartoons of Mohammed illustrate that societies

CO MPUTERS AN D DIG IT AL B AS IC S

Digital technologies and communications networks make it easy to cross cultural and geographic boundaries. News, television shows, music, and art from all over the globe are accessible on the Internet. The Internet has the potential to expand freedom of speech by offering every person on the planet a forum for personal expression using personal Web sites, blogs, chat groups, social media, and collaborative wikis. Anonymous Internet sites such as Freenet and anonymizer tools that cloak a person’s identity even make it possible to exercise freedom of speech in situations where reprisals might repress it. Internet information that seems innocuous in some cultures is not acceptable in others. Governments, parents, and organizations sometimes find it necessary to censor the Internet by limiting access and filtering content. Despite attempts to censor and filter speech on the Internet, it seems clear that digital technology opens the door to freedom of expression in unprecedented ways. Limitations on Internet speech are likely to change, too, as technology evolves and as societies come to grips with the balance between freedom and responsibility.

Has digital technology changed the way we view privacy? Citizens of free societies have an expectation of privacy, which in the words of Supreme Court Justices Warren and Brandeis is “the right to be let alone.” Digital technology use has exerted substantial pressure to diminish privacy by making it possible to easily collect and distribute data about individuals without their knowledge or consent. Privacy also encompasses confidentiality —the expectation that personal information will not be collected or divulged without permission. Internet marketers have a whole bag of tricks for surreptitiously getting personal information, and hackers are adept at breaking into sensitive databases to obtain confidential information. Surveillance is viewed by many people as an invasion of privacy. Tracking technologies embedded in cars, clothing, passports, and devices such as cell phones make it much too easy to track people without their knowledge. In the United States, the expectation of privacy is derived from Fourth Amendment protections against unreasonable searches and seizures. The Fourth Amendment was formulated long before the digital revolution. Today’s lawmakers struggle to strike the right balance between privacy and competing principles, such as free speech or free trade. Some individuals dismiss the erosion of privacy saying, “I have nothing to hide, so I don’t care.” There was a time when even they typically didn’t want stores, hackers, and curious onlookers to have access to data about what they buy, read, and watch; who they call; where they travel; and what they say. Social media, however, encourage participants to reveal personal details online, and that information is being captured, aggregated, reposted, and distributed publicly. Privacy advocates fear that these digital technologies are fundamentally changing our expectation of what is private and what is not.

FIGURE 1-10

The 1960 movie Inherit the Wind was based on the trial of John Scopes, who was accused of violating a state law that prohibited teaching evolution in state-funded schools.

draw the freedom of speech line in different places. The types of expression that are allowed or prohibited in a particular country are, in many respects, a reflection of its culture (Figure 1-10).

The Internet

Chapter Contents

SECTION A: INTERNET TECHNOLOGY Background Internet Infrastructure Internet Protocols, Addresses, and Domains Connection Speed

SECTION B: FIXED INTERNET ACCESS Dial-up Connections DSL Cable Internet Service Satellite Internet Service Fixed Wireless Service Fixed Internet Connection Roundup

SECTION C: PORTABLE AND MOBILE INTERNET ACCESS Internet to Go Wi-Fi Hotspots Portable and Mobile WiMAX Portable Satellite Service Cellular Data Service SECTION D: INTERNET SERVICES Cloud Computing Real-time Messaging Voice over IP Forums, Wikis, Blogs, and Tweets Grid Computing FTP File Sharing Networks SECTION E: INTERNET SECURITY Intrusion Attempts Securing Ports NAT Virtual Private Networks

ISSUE: WHAT’S A REVOLUTION WITHOUT THE INTERNET?

INFORMATION TOOLS: CITATIONS

TECHNOLOGY IN CONTEXT: BANKING

NEW PERSPECTIVES LABS

INFOWEBLINKS You’ll find updates for chapter material by connecting to the NP2013 Chapter 6 InfoWebLink. CLICK TO CONNECT www.infoweblinks.com/np2013/ch06

238

Learning Objectives After reading this chapter, you will be able to answer the following questions by completing the outcomes-based Learning Objectives Checkpoints on page 295. 1. Who created the Internet? 2. How does the Internet work? 3. What is TCP/IP? 4. What are the differences between static IP addresses, dynamic IP addresses, private IP addresses, and domain names? 5. Can I find the actual speed of my Internet connection? 6. What is the best type of Internet service? 7. Is there a difference between portable Internet access and mobile Internet access? 8. How do cell phones and other handheld devices access the Internet? 9. How do chat, instant messaging, and other Internetbased communications work? 10. How does Voice over IP work? 11. What are grid and cloud computing? 12. How is FTP different from file sharing technologies such as BitTorrent? 13. How do hackers break into computers? 14. How can I protect my computer from intrusions?

Note: For Chapter 5 in this edition of NP2013 see Chapter 6 in the original edition. Infoweblinks are as they appear in the original edition.

5 THE INTERNET

Apply Your Knowledge The information in this chapter will give you the background to: t Find your computer’s Internet address

t Access the Internet from a Wi-Fi hotspot

t Get a domain name for your Web site

t Access the Internet from a mobile phone

t Measure the speed of your Internet connection

t Use Internet services such as instant messaging, chat, FTP, Voice over IP, and BitTorrent

t Select the best Internet access services for your location and budget

t Protect your computer from online intrusions

Try It! HOW FAST AND DEPENDABLE IS MY INTERNET CONNECTION? You can access the Internet in various ways—using your phone line, your cable TV connection, or a personal satellite dish. Is your Internet connection fast enough for activities such as downloading DVDs and playing online multiplayer games? You can discover the speed of your Internet connection by doing the following steps: 1. Windows: Click the Start button, point to All Programs, click Accessories, and then select Command Prompt from the list. This action opens a “DOS box.” Type Ping www.google.com and then press the Enter key. Mac: Click the Finder icon, select Applications, Utilities, and Terminal. This action opens the Terminal window. Type Ping -c 4 www.google.com and then press the Enter key.

2. Your computer makes four attempts to access Google and measures the time required for each attempt. Fill in the blanks below with the Ping statistics for your computer. When you read the chapter, you’ll learn how those statistics stack up for videoconferencing, Voice over IP, and online multiplayer gaming. 3. Close the DOS box or Terminal window.

Pa Packets sent: ____ Pa Packets received: ___ Pa Packets lost: ____ Ro Round trip minimum: ____ ms Ro Round trip maximum: ____ ms Ro Round trip average: _____ ms

239

Internet Service Providers

Network Access Points

Network Service Providers

Domain Name Servers ICANN

Domain Name System

Internet Backbone

Internet Technology Latency

Upstream/ Downstream Speed Asymmetric/ Symmetric Connection

Protocols

Connection Speed

TCP/IP Traceroute

Ping

DNS Poisoning

Static IP Address Dynamic IP Address

TCP

IP IPv4 IPv6

Internet Technology SECTION

TO MOST PEOPLE, the Internet seems old hat. Even people who haven’t used the Internet know a lot about it from watching the news, reading magazines, and watching movies. Using the Internet is actually pretty easy. Browsing Web sites, shopping at Amazon.com, sending e-mail, and tweeting? No problem. But what makes the Internet “tick”? How can one network offer so much information to so many people? Section A pulls back the curtain and gives you a glimpse of what happens behind the scenes on the Net. How did the Internet get started? The history of the Internet begins in 1957 when the Soviet Union launched Sputnik, the first manmade satellite. In response to this display of Soviet superiority, the U.S. government resolved to improve its scientific and technical infrastructure. One of the resulting initiatives was the Advanced Research Projects Agency (ARPA). ARPA swung into action with a project designed to help scientists communicate and share valuable computer resources. The ARPANET, created in 1969, connected computers at UCLA, Stanford Research Institute, University of Utah, and University of California at Santa Barbara (Figure 5-1). In 1985, the National Science Foundation (NSF) used ARPANET technology to create a larger network, linking not just a few mainframe computers, but entire LANs at each site. Connecting two or more networks creates an internetwork, or internet. The NSF network was an internet (with a lowercase i). As this network grew throughout the world, it became known as the Internet (with an uppercase I).

240

FIGURE 5-1

An original diagram of the ARPANET included four nodes, depicted as circles.

Courtesy of the Computer History Museum

BACKGROUND

241

THE INTERNET

How did the Internet become so popular? Early Internet pioneers used primitive command-line user interfaces to send e-mail, transfer files, and run scientific calculations on Internet supercomputers. Finding information was not easy and access was limited to a fairly small group of educators and scientists. In the early 1990s, software developers created new user-friendly Internet access tools, and Internet accounts became available to anyone willing to pay a monthly subscription fee.

How big is the Internet today? With an estimated 500 million nodes and more than 2 billion users, the Internet is huge. Although exact figures cannot be determined, it is estimated that the Internet handles more than an exabyte of data every day. An exabyte is 1.074 billion gigabytes, and that’s a nearly unimaginable amount of data.

INTERNET INFRASTRUCTURE How is the Internet structured? Surprisingly, the Internet is not owned or operated by any single corporation or government. It is a data communications network that grew over time in a somewhat haphazard configuration as networks connected to other networks and to the Internet backbone. What is the Internet backbone? The Internet backbone is a network of high-capacity routers and fiber-optic communications links that provides the main routes for data traffic across the Internet. At one time, the Internet backbone and interconnected networks might have resembled a spine with ribs connected along its length. Today, however, it more resembles a map of interstate highways with many junctures and redundant routes.

How does the backbone tie the Internet together? Backbone links and routers are maintained by network service providers (NSPs), such as AT&T, British Telecom, Deutsche Telekom, Sprint, and Verizon. NSP equipment and links are tied together by network access points (NAPs), so that, for example, data can begin its journey on a Verizon link and then cross over to a Sprint link, if necessary, to reach its destination. NSPs supply Internet connections to large Internet service providers, such as EarthLink, AOL, AT&T, and Comcast. An Internet service provider (ISP) is a company that offers Internet access to individuals, businesses, and smaller ISPs. Figure 5-2 shows a simplified conceptual diagram of the Internet backbone and its components.

FIGURE 5-2

The Internet backbone includes high-speed routers and highspeed fiber-optic links. Parts of the backbone maintained by different communications companies are connected at network access points (NAPs).

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S EC T I O N A , C H A P T ER 5

What kinds of network devices are part of an ISP? An ISP operates routers, communication equipment, and other network devices that handle the physical aspects of transmitting and receiving data between their subscribers and the Internet. Many ISPs also operate e-mail servers to handle incoming and outgoing mail for their subscribers. Some ISPs have Web servers for subscriber Web sites. An ISP might operate a server that translates an address, such as www. google.com, into a valid IP address, such as 208.50.141.12. ISPs can also maintain servers for online discussions, instant messaging, music file sharing, FTP, streaming video, and other file transfer services (Figure 5-3).

FIGURE 5-3

ISP Equipment.

Router sends and receives data over the Internet. E-mail E server d distributes e e-mail messages. m

W server Web h holds s subscriber W Web p pages.

Domain name server tracks addresses of network devices.

TERMINOLOGY NOTE

Communications equipment receives and transmits signals to subscribers.

The word modem is derived from the words modulate and demodulate. In communications lingo, modulation means changing the characteristics of a signal, as when a dial-up modem changes a digital pulse into an analog audio signal that travels over telephone lines. Demodulation means changing a signal back to its original state.

How does my computer fit into the structure of the Internet? To communicate with an ISP, your computer uses some type of communications device, such as a modem. A modem contains circuitry that converts the data-carrying signals from your computer to signals that can travel over various communications channels. The kind of modem you use depends on whether you are connecting to a dial-up, wireless, cable, satellite, or DSL Internet service. A standalone computer can communicate with an ISP directly through a modem, or through a combination of a router and modem. If your computer is part of a network, the network’s router communicates with a modem to handle the Internet connection. Figure 5-4 illustrates the difference between standalone and LAN Internet access.

FIGURE 5-4

Your computer can connect to the Internet as a standalone device or part of a LAN. Your data first travels to your ISP, then to an NSP and out over the Internet backbone.

Internet backbone To destination

Router

NSP Router

Standalone access

ISP R t Router and/or modem

Standalone computer

LAN access Router

Modem M d m

Networked computers

243

TH E INTERNET

INTERNET PROTOCOLS, ADDRESSES, AND DOMAINS What protocols are used by the Internet? The Internet uses a variety of communications protocols to support basic data transport and services, such as e-mail, Web access, and downloading. Figure 5-5 briefly describes some of the main protocols used on the Internet.

FIGURE 5-5

Protocols Used on the Internet.

Protocol

Name

Function

TCP

Transmission Control Protocol

Creates connections and exchanges packets of data

Internet Protocol

Provides devices with unique addresses

UDP

User Datagram Protocol

An alternative data transport to TCP used for DNS, Voice over IP, and file sharing

HTTP

Hypertext Transfer Protocol

Exchanges information over the Web

FTP

File Transfer Protocol

Transfers files between local and remote host computers

POP

Post Office Protocol

Transfers mail from an e-mail server to a client Inbox

SMTP

Simple Mail Transfer Protocol

Transfers e-mail messages from client computers to an e-mail server

VoIP

Voice over Internet Protocol

Transmits voice conversations over the Internet

IRC

Internet Relay Chat

Transmits text messages in real time between online users

BitTorrent

Distributes files using scattered clients rather than a server

How significant is TCP/IP? TCP/IP is the primary protocol suite responsible for message transmission on the Internet. A protocol suite is a combination of protocols that work together. TCP (Transmission Control Protocol) breaks a message or file into packets. IP (Internet Protocol) is responsible for addressing packets so that they can be routed to their destination. From a practical perspective, TCP/IP provides a protocol standard for the Internet that is public, free, extensible, and easy to implement.

Does the Internet use a special addressing scheme? In the previous chapter, you learned that IP addresses can be assigned to LAN workstations. IP addresses originated on the Internet as part of the TCP/IP protocol. IP addresses are used to uniquely identify computers on the Internet as well as on LANs. In the context of the Internet, IP addresses are sometimes referred to as TCP/IP addresses or Internet addresses.

How do IP addresses work on the Internet? Every device on the Internet has an assigned IP address such as 128.110.192.40. In binary, the addresses are 32 bits long, but they are usually written as decimal numbers and divided by periods into four groups called octets. The numbers in each octet correspond to network classes. For example, an IP address that begins with a number between 128 and 191 corresponds to a Class B network, such as a large college campus. When delivering a packet of data, Internet routers use the first octet to get a general idea of where to send the packet. The rest of the IP address is used to drill down to the exact destination.

Do octets correspond to the parts of e-mail or Web site addresses? E-mail addresses such as imastudent@uga.edu and Web site addresses such as http://www.uga.edu are separated into parts with periods, similar to the octets in an IP address. The octets do not, however,

TERMINOLOGY NOTE 32-bit IP —referred to as IPv4— offers about 4 billion unique addresses. When even more addresses are needed, IPv6 can offer billions and billions of addresses. An IPv6 address is 128 bits and usually written as eight groups of four hexadecimal digits, such as 2001:0db8:0: 0:1319:8a2e:0370:57ab.

244

S EC T I O N A , C H A P T ER 5

map to the parts of a Web site address or an e-mail address. So, although http://www.uga.edu has an IP address of 128.192.1.9, the first octet, 128, does not correspond to http://. Nor does the second octet map to www.

Do I need a permanent IP address? A computer can have a permanently assigned static IP address or a temporarily assigned dynamic IP address. As a general rule, computers on the Internet that act as servers use static IP addresses. ISPs, Web sites, Web hosting services, and e-mail servers that always need to be found at the same address require static IP addresses. Most other Internet users have dynamic IP addresses. Figure 5-6 illustrates a tool you can use to find your IP address.

Why doesn’t everyone have a static IP address? The use of 12-digit addresses such as 128.192.100.100 provides approximately 4.3 billion unique addresses, but many of these are reserved for special purposes and devices, leaving a meager number of IP addresses for billions of Internet users. To avoid running out of static IP addresses, dynamic addresses are used whenever possible. Dynamic IP addresses can be handed out as necessary and reused as needed. How do I get a dynamic IP address? Every ISP controls a unique pool of IP addresses, which can be assigned to subscribers. If you have the type of Internet connection that requires a modem to make a telephone connection, for example, your ISP’s DHCP server assigns a temporary IP address to your computer for use as long as it remains connected. When you end a session, that IP address goes back into a pool of addresses that can be distributed to other subscribers when they log in. Your computer is rarely assigned the same dynamic IP address it had during a previous session. As an IP nomad with no permanent address, you can’t feasibly run a Web site or perform other server-related activities on your computer. For example, if you try to run an online store, its address would change every time you connect to the Internet and customers would not be able to find it. If you want to operate a server, your ISP should be able to supply you with a service plan that includes a static IP address and adequate bandwidth for server activity.

FIGURE 5-6

You can find your computer’s IP address on a Mac (left) using System Preferences or in Windows (right) using the Network and Sharing Center.

245

TH E INTERNET

How does a dynamic IP address relate to an alwayson connection? Most high-speed Internet connections use always-on technology. An always-on connection is linked to your ISP and is online whenever your computer and modem are on, even if you are not actively accessing the Internet. An always-on connection can have a static or dynamic IP address. With an always-on connection, your dynamic IP address might remain the same unless you turn off your modem, or your service provider might randomly change your IP address from time to time.

Always-on connections are convenient. You don’t have to wait for a connection to be established before using your browser or sending e-mail. If you have an always-on connection, however, you should be aware that it poses a security risk. With an always-on connection, your computer is connected to the Internet for long periods of time with the same IP address, making it particularly vulnerable to hackers. In Section E, you’ll learn how routers and firewalls can protect computers that have always-on Internet connections.

What’s a domain name? Although IP addresses work for communication between computers, people find it difficult to remember long strings of numbers. Therefore, most Internet servers also have an easyto-remember name, such as nike.com. By convention, you should type domain names using all lowercase letters. The official term for this name is fully qualified domain name (FQDN), but most people just refer to it as a domain name. A domain name is a key component of Web page addresses and e-mail addresses (Figure 5-7). FIGURE 5-7

www.msu.edu/infotech jbillings@msu.edu Web address

E-mail address

A domain name ends with an extension that indicates its top-level domain. For example, in the domain name msu.edu, edu indicates that the computer is maintained by an educational institution. Country codes also serve as top-level domains. Canada’s top-level domain is ca; the United Kingdom’s is uk; Australia’s is au; the European Union uses eu as a toplevel domain. Some of the most commonly used top-level domains are listed in Figure 5-8.

Domain names are part of the addresses for servers that handle e-mail and Web sites.

FIGURE 5-8

Top-level Domains.

Domain

Description

biz

Unrestricted use; usually for commercial businesses

com

Unrestricted use; usually for commercial businesses

edu

Restricted to North American educational institutions

gov

Restricted to U.S. government agencies

info

Unrestricted use

int

Restricted to organizations established by international treaties

mil

Restricted to U.S. military agencies

mobi

Available for sites that cater to mobile devices such as smartphones

net

Unrestricted use; traditionally for Internet administrative organizations

org

Unrestricted use; traditionally for professional and nonprofit organizations

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S EC T I O N A , C H A P T ER 5

How are domain names related to IP addresses? Every domain name corresponds to a unique IP address that has been entered into a huge database called the Domain Name System (DNS). Any computer that hosts this database is referred to as a domain name server. A domain name, such as travelocity.com, must be converted into an IP address before packets can be routed to it. Figure 5-9 illustrates what happens when you type www.travelocity.com into your browser. 2. Your ISP routes your entry to a domain name server. com ocity. vel a r t

1. You enter the address www.travelocity.com. co m ity . oc l ve

Domain name server

www

.tr

ISP

1 5 1.1 9 3.1 65

6 65

A domain name request is routed through your ISP to your designated domain name server, which searches through its database to find a corresponding IP address. The IP address can then be attached to packets, such as requests for Web pages.

3. The domain name server returns the corresponding IP address.

1 5 1 .1 9 3.1

.12

FIGURE 5-9

Why don’t I notice a pause when I enter a domain name? Although it seems as if you might have to wait quite a while to receive an IP address after you enter a domain name, that is not the case. Popular domain names are “cached” at your ISP; so in practice, you usually don’t have to wait for an IP address from a domain name server.

The DNS seems technical; why worry about it? The DNS is at the heart of the Internet. There are currently 13 domain name server systems that translate or “resolve” human-readable domain names into IP addresses. The DNS keeps track of every domain and every static IP address worldwide. When new addresses are added, they take a day or two to “propagate,” or arrive, at all the domain name servers. Until domain names are added to the DNS database, new sites can be accessed only by entering their numeric IP addresses.

Domain name server

www.travelocity.com= mybadsite.ru at 181.177.105.123

u enter the address You www.travelocity.com.

.com

1 8 1 .1 7 7.1

Instead of going to www.travelocity.com, you’ll end up at the hacker’s site!

FIGURE 5-10

After a hacker poisoned this domain name server, requests for Travelocity are routed to the IP address of the hacker’s malicious site. © Leloft1911 | Dreamstime.com

it y lo c

If a domain name server malfunctions or is hacked, Internet users can get directed to the wrong Web site. This misdirection, called DNS cache poisoning, has been used by governments to keeps citizens away from Web sites that supply politically or culturally inflammatory information. DNS cache poisoning is also a tool of hackers who want to direct users to sites infected with worms or keyloggers (Figure 5-10).

247

THE INTERNET

Do I need my own domain name? For client-style Internet activities, such as Web browsing, e-mail, and chat, you do not need your own domain name. You might, however, want a domain name if you plan to operate your own Web server or if you establish a Web site using a server provided by a Web site hosting service. How do I get a domain name? An organization called ICANN (Internet Corporation for Assigned Names and Numbers) is recognized by the United States and other governments as the global organization that coordinates technical management of the Internet’s Domain Name System.

ICANN supervises several for-profit Accredited Domain Registrars, which handle domain name requests. You can select a domain name and register it for a minimal annual fee —currently between US$10 and $50, depending on the registration service (Figure 5-11). FIGURE 5-11

The first step in registering a domain name is to find out whether the name is currently in use or reserved for future use. If a domain name is not available, consider using a different toplevel domain, such as biz instead of com. After you’ve found an available domain name, you can continue the registration process by filling out a simple online form.

CONNECTION SPEED How fast is the Internet? Data travels over the Internet at an incredible speed. On average, data usually arrives at its destination in less than a second after it is sent. Data transport can slow down, however, when usage peaks during breaking news events, or when denial-of-service attacks break through security. Such slow-downs are temporary, however, and usually last only a few hours. The elapsed time for data to make a round trip from point A to point B and back to point A is referred to as latency. Latency generally averages less than 100 ms (milliseconds) in North America. Latency increases slightly for overseas transmissions. If you want to play online multiplayer games, it is best to have less than 100 ms latency. Good-quality Voice over IP and videoconferencing require latency rates of 200 ms or less.

Can I measure speed and latency? You can use a local Internet utility called Ping (Packet Internet Groper), which sends a signal to a specific Internet address and waits for a reply. When a reply arrives, Ping reports that the computer is online and displays the elapsed time for the round-trip message. You can use Ping before playing online games, using Voice over IP, joining an online videoconference, or streaming a Netflix movie to make sure you have adequate speed for everything to run smoothly.

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S EC T I O N A , C H A P T ER 5

Ping also shows whether packets were lost in transmission. Packets can become lost when signal interference or network congestion overwhelms Internet servers and routers. Lost packets can cause jitter in Voice over IP communications and videoconferencing. Too many lost packets during an online gaming session can cause the game to stutter or stall. And if packets don’t arrive in the correct order, your game character might seem to act randomly for a few seconds. Another utility called Traceroute records a packet’s path in addition to its round-trip speed. You can use Traceroute to analyze the latency of your data as it hops from one Internet router to the next (Figure 5-12). FIGURE 5-12

A list of routers indicates the path of the packet sent by Traceroute.

Latency between 757 ms and 3,378 ms indicates a very slow round trip.

The trace timed out before the packet arrived at its destination —all in all, a “bad” connection.

How fast is a typical Internet connection? The connection speeds advertised by ISPs refer to the amount of data that travels between a subscriber’s computer and an ISP within a given time period. Connection speed is measured in Kbps (kilobits per second) or Mbps (megabits per second). Slow dial-up connections top out at 56 Kbps. High-speed (also called broadband) connections at 10,000 Kbps (10 Mbps) are common. High-speed connections can display graphics quickly, show smoothly streaming video, handle net-based videoconferences, and deliver high-quality Voice over IP.

What factors affect connection speed? Your connection speed depends on whether you connect to your ISP using a telephone, cable television, satellite, or wireless link. Actual speed can differ from maximum speed because links are susceptible to interference that can hinder signals. Upstream speed can also differ from downstream speed. What are upstream and downstream speeds? Upstream speed is the rate of data that is uploaded from your computer to the Internet. Downstream speed is the rate of data downloaded to your computer. Many ISPs limit these speeds to make sure everyone gets an equal share of the bandwidth. Usually, upstream speed is slower than downstream speed. When upstream speeds differ from downstream speeds, you have an asymmetric Internet connection. When upstream and downstream

In this example, Traceroute is used to monitor an Internet connection between a small lakeside cabin in northern Michigan and the HotWired Web site. The satellite connection has extremely high latency and timed out before the Web site could be accessed.

249

THE INTERNET

speeds are the same, you have a symmetric Internet connection. Asymmetric connections discourage subscribers from setting up Web and e-mail servers that would transmit lots of upstream data. For most users, however, an asymmetric connection is sufficient. You can use an Internet-based utility, such as Speedtest.net, to see if your Internet connection achieves the speed advertised by your ISP (Figure 5-13). FIGURE 5-13

Speed tests measure the average number of bits that are transmitted per second, whereas utilities such as Ping and Traceroute measure the time required for a packet to make a round trip from your computer and back.

Upload and download speeds.

What are my connection options? Consumers have several options for connecting to the Internet. Fixed Internet access links your computer to an ISP from a stationary point, such as a wall socket or roofmounted antenna. Portable Internet access allows you to easily move your access device, as in the case of vehicle-mounted satellite dishes that can be deployed when the vehicle is parked. Mobile Internet access allows you to use the Internet as you are on the go, such as using a cell phone to collect your e-mail while you are traveling by train. You’re not necessarily limited to a single Internet access option. Many consumers find it convenient to maintain fixed Internet access for home use, but use a portable or mobile method of Internet access while out and about. In Sections B and C you’ll learn more about Internet access options.

SECTION A

QuickCheck 1.

TCP/

is the primary proto-

If you ping Google from your computer and get a

col suite used on the Internet.

result of 46 ms, you have a relatively slow Internet

204.127.129.1 is an example of an IPv4 address.

connection. True or false? 5.

True or false? 3.

A(n)

name server main-

tains a database of IP addresses that correspond to addresses such as www.nike.com.

Most ISPs offer

Internet

connections, meaning the downstream speed is faster than the upstream speed.

250

C H A P T ER 6

DSL Modems

DSL Filters

Cable Modems

Voiceband Modems

DOCSIS

DSL

Cable

Dial-up

Satellite Modems

Internet Access

WiMAX

Satellite Satellite Dishes

Fixed Internet Access SECTION

ONE OF THE MOST challenging aspects of the Internet is selecting a service provider. In this section of the chapter, you’ll learn about fixed Internet access, which is typically your main link to the Internet. You’ll learn to evaluate the pros and cons of various fixed Internet options, and discover why online interactive game players shun satellite Internet connections but love cable Internet service. Plus, you’ll find out which types of Internet access work best for Voice over IP.

DIAL-UP CONNECTIONS What is a dial-up connection? A dial-up connection is a fixed Internet connection that uses a voiceband modem and telephone lines to transport data between your computer and your ISP. ISPs, such as NetZero, AOL, and EarthLink, still offer dial-up Internet access. The service typically costs less than $10 per month, but access speed is slow. How does a dial-up connection work? When you use a dialup connection, your computer’s modem places a regular telephone call to your ISP. When the ISP’s computer answers your call, a dedicated circuit is established between you and your ISP —just as though you had made a voice call and someone at the ISP had picked up the phone.

FIGURE 5-14

When you use a dial-up connection to access the Internet, your data travels over local telephone lines to your ISP, which sends it onto the Internet.

The circuit remains connected for the duration of your call and provides a communications link that carries data between your computer and the ISP. As your data arrives at the ISP, a router sends it out over the Internet (Figure 5-14).

To the Internet.

Your computer Y and modem.

Telephone wall jack.

ISP’s modem.

ISP’s router. router

ISP

250

251

THE INTERNET

How does a voiceband modem work? The signals that represent data bits exist in your computer as digital signals. The telephone system, however, expects to work with human voices, so it carries analog audio signals. A voiceband modem —usually referred to simply as a modem— converts the signals from your computer into audible analog signals that can travel over telephone lines. A modem transmits a 1,070 Hz tone for a 0 data bit and a 1,270 Hz tone for a 1 data bit.

When your computer’s modem initiates a connection, it sends a signal that is equivalent to picking up the receiver of a telephone to get a dial tone. It then dials the ISP by emitting a series of tones —the same tones you’d produce if you punched in the ISP’s number using a phone keypad. The modem then waits for the ISP’s modem to answer the call. After the ISP’s modem answers, the two modems begin to negotiate communications protocols, such as transmission rate. The series of beeps, tones, and whooshing sounds you hear when you connect to your ISP is the sound of your modem “talking” to the ISP’s modem. This process of negotiation is sometimes called handshaking. When the negotiation is complete, data transmission can begin (Figure 5-15).

Digital signal. Dig

Your computer generates a digital signal.

Analog audio signal.

Your modem changes the digital signal into an analog audio signal.

FIGURE 5-15

When you transmit data, your voiceband modem modulates the signal that carries your data. A modem at the other end of the transmission demodulates the signal.

Digital signal. ignal.

The receiving modem converts the analog signal back into a digital signal.

How fast is a voiceband modem? Modem speeds are measured in bits per second. (If you’re a stickler for details, you’ll realize that bps is actually a measure of capacity, but everyone calls it speed.) Most modems use a standard called V.90 to provide a theoretical maximum speed of 56 Kbps. Actual data transfer speeds are affected by factors such as the quality of your phone line and connection. Even with an excellent connection, however, a 56 Kbps modem tops out at about 44 Kbps. Dial-up connections are asymmetrical; 44 Kbps is a typical download speed for a 56 Kbps modem. For uploads, the data rate drops to about 33 Kbps or less.

Can I use an analog modem if my phone service is digital? In many areas of the world, the telephone system uses digital rather than analog signals to send voice conversations. You can still use an analog modem because the sounds it emits are transported just as if they were voices. Digital telephone systems open up the possibilities for digital data transport options such as ISDN and DSL. ISDN service offered slightly faster service than dial-up but has today been replaced by DSL.

Computer Concepts 2013 C O M PREHEN SIVE • 1 5 T H B RIEF EDIT ION

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S k ill s

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C r it

We live in a digital world and pick up bits and pieces of information about computers and other digital devices. But understanding digital devices in a way expected of a college graduate requires a framework of concepts that organizes information into hierarchies and relationships. It is, in a sense, the social network of learning. New Perspectives Computer Concepts 2013 15th Brief Edition is designed to help students connect the dots to visualize and internalize a framework for technology concepts that’s applicable to academic research, career preparation and today’s digital lifestyles.

Want to see more? For more information about the New Perspectives Series, please visit: www.cengage.com/ct/newperspectives

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