|
| Introduction 21
|
|
| Sound, Vibrations, And Analog Recording 21
|
|
| Analog Electronic Devices 22
|
|
| Many Electronic Devices Are Analog 23
|
|
| The First Analog Communication 23
|
|
| Analog Is Simple But Inaccurate 23
|
|
| Sending An Analog Signal Across A Wire 24
|
|
| Digital Music 25
|
|
| The Digital Revolution 25
|
|
| Computers Are Digital 26
|
|
| Digital Recording 26
|
|
| Using Digital To Recreate Analog 27
|
|
| Why Digital Music? 28
|
|
| Summary 28
|
|
| Many Independent Networks 57
|
|
| The Proliferation Of LANs 57
|
|
| Facts About LANs 58
|
|
| LANs Are Incompatible 59
|
|
| Wide Area Technologies Exist 59
|
|
| Few WANs, Many LANs 60
|
|
| WANs and LANs Are Incompatible 61
|
|
| The Desirability Of A Single Network 61
|
|
| The Department Of Defense Had Multiple Networks 62
|
|
| Connecting Disconnected Machines 62
|
|
| The Internet Emerges 62
|
|
| The ARPANET Backbone 63
|
|
| Internet Software 63
|
|
| The Name Is TCP\^/\^IP 64
|
|
| The Shock Of An Open System 64
|
|
| Open Systems Are Necessary 65
|
|
| TCP\^/\^IP Documentation Is Online 65
|
|
| The Military Adopts TCP\^/\^IP 67
|
|
| Summary 67
|
|
| A Personal Note 67
|
| For Further Study 68
|
|
| Introduction 69
|
|
| Disseminating The Software 69
|
|
| Meanwhile, Back In Computer Science 70
|
|
| The Internet Meets UNIX 70
|
|
| The U.S. Military Makes A Commitment 71
|
|
| The Internet Doubles In Size In One Year 71
|
|
| Every Computer Science Department 72
|
|
| Graduate Students Volunteer Their Time 73
|
|
| The IAB evolves 73
|
|
| The IETF 74
|
|
| Doubling Again In A Year 74
|
|
| The Internet Improves Science 75
|
|
| NSF Takes A Leadership Role 75
|
|
| Target: All Of Science And Engineering 75
|
|
| NSF's Approach 76
|
|
| The NSFNET Backbone 76
|
|
| The ANS Backbone 77
|
|
| Exponential Growth 78
|
|
| A Commercial Assessment 79
|
|
| The End Of Growth 80
|
| For Further Study 80
|
|
| Introduction 97
|
|
| Sharing Saves Money 97
|
|
| Sharing Introduces Delays 98
|
|
| Sharing Wires 98
|
|
| Selectable Channels 98
|
|
| Sharing By Taking Turns 99
|
|
| Packet Switching Avoids Delays 100
|
|
| Each Packet Must Be Labeled 100
|
|
| Computers Have Addresses 100
|
|
| Packets Are Not All The Same Size 101
|
|
| Packet Transmission Seems Instantaneous 101
|
|
| Sharing Is Automatic 102
|
|
| Network Hardware Handles Sharing 102
|
|
| Many Devices Can Use Packet Switching 102
|
|
| Relevance To The Internet 103
|
|
| Summary 103
|
|
| Introduction 105
|
|
| Network Technologies Are Incompatible 105
|
|
| Coping With Incompatibility 106
|
|
| Two Fundamental Concepts 106
|
|
|
| - A Connection To A Network Can Be Extended 107
|
|
|
| - A Computer Can Have Multiple Connections 108
|
|
| Using A Computer To Interconnect Networks 108
|
|
| Interconnecting Computers Pass Packets 109
|
|
| Interconnecting Computers Are Called Routers 110
|
|
| Routers Are The Building Blocks Of The Internet 110
|
|
| The Internet Includes Multiple Types Of Networks 111
|
|
| Routers Can Interconnect WANs And LANs 111
|
|
| The Hierarchical Structure Of The Internet 113
|
|
| Where Packets Travel 114
|
|
| Interconnecting Networks Was Revolutionary 114
|
|
| Summary 115
|
|
| Introduction 117
|
|
| Internet Service Providers And Fees 117
|
|
| Customer Connections Form The Last Mile 118
|
|
| Leased Circuits Are Expensive 118
|
|
| Dial-up Access Is Inexpensive, But Slow 119
|
|
| Broadband Connections Offer High Speed 120
|
|
| The Important Concept Of Continuous Connectivity 120
|
|
| Instantaneous Access Changes Use 121
|
|
| Modern Technologies Offer Inexpensive Dedicated Access 121
|
|
|
| - Cable Modems 122
|
|
|
| - DSL Technology And Telephones 123
|
|
| Wireless Access Is Available 124
|
|
| Wi-Fi And 3G Wireless Technologies 124
|
|
| A Personal Note 125
|
|
| Introduction 127
|
|
| Protocol: An Agreement For Communication 127
|
|
| Basic Functionality: The Internet Protocol 128
|
|
| IP Software On Every Machine 128
|
|
| Internet Packets Are Called Datagrams 128
|
|
| The Illusion Of A Giant Network 129
|
|
| The Internet's Internal Structure 130
|
|
| Datagrams Travel In Packets 131
|
|
| Every Computer Is Assigned A Unique Address 132
|
|
| Internet Addresses 132
|
|
| An Odd IP Address Syntax 132
|
|
| IP Addresses Are Not Random 133
|
|
| A Trip Through An Example Internet 133
|
|
| How Fast Is Your Connection? 134
|
|
| Summary 135
|
|
| Introduction 149
|
|
| People Prefer Names To Numbers 149
|
|
| Naming A Computer Can Be Challenging Or Fun 150
|
|
| Computer Names Must Be Unique 151
|
|
| Suffixes On Computer Names 151
|
|
| Names With Many Parts 152
|
|
| Domain Names Outside The US 153
|
|
| Translating A Name To An Equivalent IP Address 154
|
|
| Domain Name System Works Like Directory Assistance 154
|
|
| Computer Name Lookup Is Automatic 155
|
|
| IP Addresses And Domain Names Are Unrelated 156
|
|
| Summary 157
|
|
| Introduction 173
|
|
| Description Of Functionality 173
|
|
| The Best Of All Worlds 174
|
|
| Each User Has A Mailbox For Email 174
|
|
| Sending An Email Message 174
|
|
| Notification That Email Has Arrived 175
|
|
| Reading An Email Message 175
|
|
| A Browser Can Be Used To Send And Receive Email 175
|
|
| Email Messages Look Like Interoffice Memos 176
|
|
| Email Software Fills In Header Information 177
|
|
| How Email Works 177
|
|
| Using Email From A Personal Computer 178
|
|
| Mailbox Address Format 179
|
|
| Abbreviations Make Email Friendly 180
|
|
| Aliases Permit Arbitrary Abbreviations 180
|
|
| Aliases Shared By All Users Of A Computer System 181
|
|
| Sending To Multiple Recipients 181
|
|
| Mailing List: An Alias for Multiple Recipients 182
|
|
| Public Mailing Lists And Mail Exploders 183
|
|
| Exchanging Email With Non-Internet Sites 183
|
|
| Access To Services Via Email 184
|
|
| Speed, Reliability, And Expectations 184
|
|
| Impact And Significance Of Electronic Mail 185
|
|
| A Convention For Joining A Mailing List 186
|
|
| Introduction 197
|
|
| Description Of Functionality 197
|
|
| Browsing Vs. Information Retrieval 198
|
|
| Early Browsing Services Used Menus 198
|
|
| A Menu Item Can Point To Another Computer 199
|
|
| How A Browser Works 200
|
|
| An Example Point-And-Click Interface 201
|
|
| Combining Menu Items With Text 202
|
|
| The Importance Of Integrated Links 204
|
|
| Embedded Links In Text Are Called Hypertext 205
|
|
| Multimedia 206
|
|
| Video And Audio References Can Be Embedded In Text 207
|
|
| The World Wide Web 208
|
|
| Browser Software Used To Access The Web 209
|
|
| An Example Hypermedia Display 209
|
|
| Control Of A Browser 212
|
|
| External References 212
|
|
| Recording The Location Of Information 213
|
|
| Bookmarks Or Favorites 215
|
|
| How The World Wide Web Works 216
|
|
| A URL Tells A Browser Which Computer To Contact 216
|
|
| A URL Tells A Browser Which Server To Contact 216
|
|
| Use Of The Name www In URLs 217
|
|
| A Browser Provides Access To Multiple Services 218
|
|
| Inside A Browser Program 218
|
|
| Summary 219
|
|
| An Observation About Hypermedia Browsing 220
|
|
| Introduction 221
|
|
| Display Hardware Varies 221
|
|
| A Browser Translates And Displays A Web Document 222
|
|
| A Consequence Of The Web Approach 223
|
|
| HTML, The Language Used For Web Documents 223
|
|
| Instructions In A Web Page Control The Output 224
|
|
| A Web Page Is Divided Into Two Main Sections 225
|
|
| Indentation Can Make HTML Readable 225
|
|
| The Body Of A Web Page Can Contain Text 226
|
|
| Indentation Can Make Paragraphs Easier To Find 226
|
|
| A Web Page Can Link To Another Page 228
|
|
| HTML Allows Numbered And Unnumbered Lists 229
|
|
| Images On A Web Page Are Digital 230
|
|
| HTML Allows A Web Page To Include An Image 232
|
|
| Text Can Appear Adjacent To An Image 233
|
|
| Images Can Link To Another Web Page 234
|
|
| Some Browsers Can Stretch Or Shrink Images 235
|
|
| The Background Can Be Controlled 235
|
|
| Other Features Of HTML 235
|
|
| Importance Of HTML 236
|
|
| GUI Tools Help With Web Page Creation 236
|
|
| Summary 237
|
|
| Introduction 239
|
|
| Conventional Web Pages Are Static 239
|
|
| How A Server Stores Static Web Pages 240
|
|
| Fetching Items One At A Time 242
|
|
| Conventional Web Pages Use The Entire Screen 242
|
|
| A Web Page Can Change Part Of the Screen 243
|
|
| The Web, Advertising, And Frames 245
|
|
| Pop-Ups And Pop-Up Blockers 246
|
|
| Static Documents Have Disadvantages 246
|
|
| Controlling How A Browser Processes Data 247
|
|
| Plugins Allow Variety 248
|
|
| A Server Can Compute A Web Page On Demand 249
|
|
| How Server-Side Scripting Works 250
|
|
| Professional Programmers Build Server Scripts 251
|
|
| Personalized Web Pages 252
|
|
| Personalized Advertisements 253
|
|
| Web Pages Can Interact 253
|
|
| Shopping Carts 253
|
|
| Cookies 254
|
|
| Should You Accept Cookies? 255
|
|
| A Web Page Can Display Simple Animations 255
|
|
| Active Documents Are More Powerful 256
|
|
| Java Is An Active Document Technology 258
|
|
| JavaScript Is An Active Document Technology 258
|
|
| Flash And Real Technologies 259
|
|
| The Importance Of Advanced Web Technologies 259
|
|
| Introduction 267
|
|
| Description Of Functionality 267
|
|
| Browsing Vs. Automated Searching 268
|
|
| A Search Engine Helps Users Get Started 268
|
|
| A Search Tool Can Help Recover From Loss 269
|
|
| How An Automated Search Service Operates 269
|
|
| Gathering Information In Advance 270
|
|
| Modern Systems Search Web Page Contents 271
|
|
| How A Web Search Appears To A User 272
|
|
| How A Search Engine Returns Results 273
|
|
| Automated Search Services Use String Matching 274
|
|
| The Advantages And Disadvantages Of String Matching 274
|
|
| Automated Search Programs That Use Multiple Keys 275
|
|
| Advanced Services Offer More Sophisticated Matching 276
|
|
| Personalized Search Results 277
|
|
| More Details About How Content Searching Works 277
|
|
| Searches Are Restricted 278
|
|
| Advertising Pays For Searching 279
|
|
| Examples Of Automated Search Services 279
|
|
| Significance Of Automated Web Search 280
|
|
| Introduction 281
|
|
| Instant Messaging Provides Textual Communication 281
|
|
| Audio And Video Functionality 282
|
|
| Audio And Video Require Special Facilities 283
|
|
| An Audio Clip Resembles An Audio CD 283
|
|
| Real-Time Means No Delay 284
|
|
| Internet Audio In Real-Time 284
|
|
| Radio Programs On The Internet 285
|
|
| Real-Time Audio Transmission Is Called Webcasting 285
|
|
| Internet Telephone Service Is Possible 286
|
|
| Internet Telephone Service Is Known As VoIP 286
|
|
| Audio Teleconferencing 287
|
|
| A Cooperative Document Markup Service 287
|
|
| Marking A Document 289
|
|
| The Participants Discuss And Mark A Document 290
|
|
| Video Teleconferencing 290
|
|
| Video Teleconference Among Groups Of People 292
|
|
| A Combined Audio, Video, Whiteboard, And IM Service 292
|
|
| Summary 293
|
|
| A Personal Note 293
|
|
| Introduction 303
|
|
| Early Computers Used Textual Interfaces 303
|
|
| A Timesharing System Requires User Identification 304
|
|
| Remote Login Resembles Conventional Login 304
|
|
| How Remote Login Works 305
|
|
| Escaping From Remote Login 305
|
|
| The Internet Remote Login Standard Is TELNET 306
|
|
| Remote Access Can Display A Desktop 306
|
|
| How Remote Desktops Operate 307
|
|
| Assessment Of Remote Login And Desktops 308
|
|
| Generality Makes Remote Login And Desktops Powerful 308
|
|
| Remote Access Accommodates Multiple Types Of Computers 309
|
|
| Unexpected Results From Remote Access 309
|
|
| Summary 310
|
|
| Introduction 311
|
|
| The Internet Is Unsecure 311
|
|
| Lack Of Security Can Be Important 312
|
|
| Authentication And Privacy Are Primary Problems 312
|
|
| Data Can Be Changed 313
|
|
| Encoding Keeps Messages Private 313
|
|
| Computer Encryption Uses Mathematics 314
|
|
| No Network Is Absolutely Secure 314
|
|
| Encryption Makes Email Private 315
|
|
| Encryption Software Needs A Key 315
|
|
| Two Keys Means Never Having To Trust Anyone 316
|
|
| Secure Email In Practice 317
|
|
| Secure Wireless Networks 318
|
|
| Firewalls Protect Networks From Unwanted Packets 318
|
|
| A Firewall Filters Packets 319
|
|
| Firewalls Guard Against Trojan Horses 320
|
|
| Residential And Individual Firewalls 320
|
|
| Systems Exist To Detect Intrusion 321
|
|
| Service Can Be Denied 321
|
|
| Summary 322
|
|
| Introduction 331
|
|
| Who Pays For The Internet? 331
|
|
| E-commerce Is Big Business 332
|
|
| Security Technology Made E-commerce Possible 333
|
|
| Secure Sockets 333
|
|
| Public Key Encryption Provides Authenticity 334
|
|
| Digital Signatures 335
|
|
| Certificates Contain Public Keys 335
|
|
| What Is Digital Money? 336
|
|
| Digital Cash Is Not Widely Available 336
|
|
| Business And E-commerce 337
|
|
| The Controversies Over Taxation And Net Neutrality 338
|