Table Of Content

Ron Illustrated by Timothy Edward Downs ® 8011 East 96thStreet Indianapolis, IN 462411 VI TABU OF CONTENTS Introduction Part 4: Data Storage 132 Xli Chapter 9 Part 1: Boot..Up How a Computer's Long-Term Memory Process 2 Works 140 Chapter 1 Chapter 10 Getting to Know the Hardware 10 How Disk Drives Save Information 152 Chapter 2 Chapter 11 How a Disk BootWakes Up Your PC 22 How the Little Things Make Disk Driv Faster and Store More Chapter 3 How an Operating System Controls Chapter 12 Hardware 28 How PCs Use Light k't:>tYl""rnht~r Data 170 Chapter 13 Part 2: Microchips 38 How Removable Storage Works Chapter 4 How Transistors Manipulate Data 44 Part 5: Input/Output Devices Chapter 5 How a Microprocessor Works 52 Chapter 14 How Energy Turns into Data Part 3: How Software Chapter 15 Works 72 How Computer Ports Work 208 Chapter 6 Chapter 16 How Programming Languages Work 86 How a Computer Display Works 21 8 Chapter 7 Chapter 17 How Windows Works 96 How Data Gets into Your PC 228 Chapter 8 Chapter 18 How Software Applications Do How Scanners Capture Images Your Work 106 and Words 238 Chapter 1 How Porta puters 6 Chapter 20 How Digital C 4 TABU OF CONTENTS VII Part 6: Games and Part 8: How Printers Multimedia 262 Work 396 Chapter 21 Chapter 32 How Multimedia Sound Works 268 How Black-and-White Printing'vVorks 402 Chapter 22 Chapter 33 How Multimedia Video Works 280 How Color Printing Works 412 Chapter 23 Index 425 How Games Put You in the Action 286 Part 7: How the Internet Works 304 Chapter 24 H cal Area Networks Work 31 2 25 sConnect to the Internet 322 pter 26 ow Wireless Sets PCs Free 332 Chapter 27 How the Internet Moves Data 340 Chapter 28 How We Reach Each Other Through the Net 346 Chapter 29 How InternetVideo and Audio Work 356 Chapter 30 How the World Wide Web Is A-Changing 362 Chapter 31 How Internet Security Fights Off PC Invaders 376 Introduction IIAny sufficientlyadvancedtechnology is indistinguishable from magic.II -Arthur C. Clarke have their magic wands-powerful, potentially dangerous tools with a lives oftheir own. Witches have their familiars-creatures disguised as household beasts that could, if they choose, wreak the witches' havoc. Mystics have their golems-beings built ofwood and tin broughtto life to do their masters' bidding. We have our personal computers. PCs, too, are powerful creations thatoften seem to have a life oftheir own. Usually, they respond to a wave ofa mouse or a spoken incantation by performing tasks we couldn't imagine doing ourselves with out some sortof preternatural help. But even as computers successfully carry outour commands, it's often difficult to quell the feeling that there's somewizardry atwork here. And then there are the times when our PCs, like malevolent spirits, rebel and open the gates ofchaos onto our neatly ordered columns of numbers, our carefullywrought sentences, and our beautifully crafted graphics. When that happens, we're often convinced thatwe are, indeed, playing with power notentirely under our control. We become sorcerers' apprentices, whose every attempt to right things leads to deeper trouble. Whetherour personal computers are faithful servants or imps, mostof us soon realize there's much more going on inside those silent boxes than we really understand. PCs are secretive. Open their tightly sealed cases and you're confronted with poker-faced components. Few give any clues as to what they're about. Mostofthem consistof sphinx-like microchips that offer no more information about themselves than some obscure code printed on their impenetrable surfaces. The maze ofcircuittracings etched on the boards is fascinating, but meaningless, hieroglyphics. Some crucial parts, such as the hard drive and power supply, are sealed with printed omens about the dangers of peeking inside-omens that putto shame the warn ings on a pharaoh's tomb. This book is based on two ideas. One is that the magic we understand is safer and more powerful than the magic we don't. This is nota hands-on how-to book. Don't look for any instructions for taking a screwdriver to this partor the other. But perhaps your knowing more aboutwhat's going on inside all those stoic camponents makes them little less formidable when something does go awry. The second idea behind this book is that knowledge, in itself, is a worthwhile and enjoyable goal. This book is written to respond to your random musings about the goings-on inside that boxyou sit in front of several hours a day. Ifthis book puts your questions to rest-or raises newones-itwill have done its job. At the same time, however, I'm trusting that knowing the secrets behind the magician's legerdemain won't spoil the show. This is a real danger. Mystery often is as compelling as knowledge. I'd hate to think that anything you read in this book takes away that sense ofwonder you have when you manage to make your PC do some grand, new trick. Ihope that, instead, this book makes you a more confident sorcerer. Before You Begin book has been written with a certain type of personal computer in mind-theWintel, a PC most often builtaround an Intel processorand running MicrosoftWindows. Manyofthe specifics in these ex planations apply only to that class ofcomputer and those components. ForMac users, IsuggestJohn Rizzo's How the Mac Works (lSBN# 0-7897-2428-6). In more general terms, the explanations also applyto Macintosh computers, Unixworkstations, and even minicomputers and mainframes. But I've made no attempt to devise universal explanations of howcom puters work. To do so would, of necessity, detractfrom the understanding that comes from inspecting spe cific components. Even so, there is so much variety even within the Intel/Microsoftworld of PCs that, attimes, I've had to limit my explanations to particular instances or stretch the boundaries ofa particular situation to make an explanation as generic as possible. Ifyou spotanything thatdoesn't seem quite right in this book, Ihope that my libertieswith the particulars is the only cause. Ron White San Antonio, Texas Ii3Pa0le,o0l0ith0icBp.eCo.plesin T2h6e0C0hiBne.Cse.introduce T2h6e0MBa.yCo.develop M15ec0h0anical W16il2li1omOughtred fG1o6t7tfr0iedLeibniz ,centralEuroperecord theobocus.Itwosused asophisticated calculator inventsthesliderule, IimprovesuponPascaline !numbersbynotching inChinoforcalculating base-20systemof inventedby whichdidnot byaddingmultiplication, ,talliesonanimalbones, thecensusasrecently mathemoticsthat Leonardodo becomeobsoletefor Idivision,andsquareroot Iivoryandstone. asAD. 1982. includeszero. Vinci, Ineorly350years. .capabilities. I f I 3400B.C. 300B.C. 11614 :1642 11679 Egyptiansdevelopasymbol Euclid'sElementssumma JohnNapierdescribes BlaisePascalinvents Leibniz forthenumber 10,simplify rizesallthemathematical thenatureoflogarithms. Pascoline,thefirstmechani introduces ingtherepresentotionof knowledgeoftheGreeks. HealsobuildsNapier's calcolculator.Itwoshond binory largenumbers. Itisusedforthenext Bones,theforerunnerto turnedandcouldonlyodd arithmetic. 2,000years. thesliderule. andsubtrocl. Boot-Up Process GETTING TO KNOW THE HARDWARE J0 HOW ADISK BOOT WAKES UP YOUR PC 22 HOW AN OPERATING SYSTEM CONTROLS HARDWARE 28 1822 1890 1902-1905 1926 1943 1 CharlesBabbageinvents HermanHollerithcreates AlbertEinsteindiscov Patentforsemiconductor Britishbuild DifferenceEngine,alarge electrictabulatingsystem ersTheoryofRelativity. transistorthatallowed Colossus,a mechanicalcalculator foru.s.CensusBureau. Hepublishesitindis electricalcurrentsto machineto capableofadditionand sertationatUniversity flowthrough<:amputer, breakGerman subtraction. ofZurich. passingdata. codes. 11830 11896 11904 11936 11943-45 CharlesBabbagecon HollerithformstheTabulating JohnAmbrose KonradZusecreatesa U,S,Armybuilds ceivesoftheAnalytical MachineCompany,which flemingdevel· programmable,digital ENIACcomputerto Enginebutdiesbefore laterbecomesInternational opsva<:oum computingmachinethat calculateweapons' itscompletion. BusinessMachines. tubes. introducesuseofbinary traiectories. systemandvalves, 4 BOOT-UP PROCESS "[thinkthereisaworldmarketformaybefivecomputers." -ThomasWatson, chairman ofIBM, 1943 your personal computer is turned on, it is a dead collection of sheet metal, plastic, metallic tracings, and tiny flakes of silicon. When you push the On switch, one little burstofelec tricity-onlyabout 3-5 volts-starts a string ofevents that magically brings to life what otherwise would remain an oversized paperweight. Even with that spark of life in it, however, the PC is still stupid at first. Ithas some primitive sense ofselfas itchecks to see what parts are installed and working, like those patients who've awakened from a coma and check to be sure they have all their arms and legs and thatall their joints still work. But beyond taking inventory of itself, the newly awakened PC still can'tdo any thing really useful; certainly nothing we would even remotely think ofas intelligent. At best, the newlyawakened PC can search for intelligence-intelligence in the form ofan operating system that gives structure to the PC's primitive, amoebic existence. Then comes a true education in the form ofapplication software-programs that tell the PC how to do tasks faster and more accuratelythan we could. The PC becomes a studentwho has surpassed its teacher. But notall kinds ofcomputers have to endure such a torturous rebirth each time they're turned on. You encounter daily many computers that spring to life fully formed atthe instantthey're switched on. You might notthink ofthem as computers, but they are: calculators, your car's elec tronic ignition, the timer in the microwave, and the unfathomable programmer in your VCR. The difference between these and the big box on your desk is hard-wiring. Computers builtto accom plish only one task-and they are efficient aboutdoing that task-are hard-wired. Butthat means they are more like idiot savants than sages. What makes your PC such a miraculous device is thateach time you turn iton, it is a tabula rasa, capable ofdoing anything your creativity-or, more usually, the creativity of professional programmers-can imagine for itto do. Itis a calculating machine, an artist's canvas, a magical typewriter, an unerring accountant, and a host ofother tools. To transform itfrom one persona to another merely requires setting some ofthe microscopic switches buried in the hearts ofthe microchips, a task accomplished by typing a command or by clicking with your mouse on some tiny icon on the screen. 1944 1948 1951 1952 1954 1958 HarvardUniversity ENIACscientistscreate UNIVACdeliveredtoUS UNlVACpredictsland IBMbringsout650,the ControlData andIBMdevelop ElectronicControl,thefirst CensusBureauthreeyears slidevictoryforEisen firstmass-produced Corporationintroduces theMark1,which computerfirm,andbegin late.Itusesmagnetictope howeronCBS.Human computer.It'sagreat SeymourCray's1604.At usesIBMpunched tobuildUNlVACfor forinputinsteadof forecastspredicttight success,with120instal $1.5million,ifshalhhe cords. CensusBureau. punchedpaper. race.UNIVACwins. lationsinfirstyear. costoftheIBMcomputer. 1 1945 11949 11952 11954 11956 1958 JohnvonNeumann PopularMechanics Acomplaintisfiled Texaslnstruments Massachusetts JackKilbycompletes describesageneral predicts:"Computers againstIBM,alleging announcesthestart Instituteof firstintegratedcircuit, purposeelectronic inthefuturemay monopolisticprac ofcommercialpro' Technologybuildsthe containingfivecom digitalcomputerwith weighnomorethan ticesinitscomputer ductionofsilicon firsttransistorized ponentsonasingle astoredprogram. 1.5tons." business. transistors. computer. pieceofsilicon.