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外文资料

3．外文资料原文

ProgressinComputers

PrestigeLecturedeliveredtoIEE,Cambridge,on5February2004

MauriceWilkes

ComputerLaboratory

UniversityofCambridge

Thefirststoredprogramcomputersbegantoworkaround1950.TheonewebuiltinCambridge,theEDSACwasfirstusedinthesummerof1949.

Theseearlyexperimentalcomputerswerebuiltbypeoplelikemyselfwithvaryingbackgrounds.Weallhadextensiveexperienceinelectronicengineeringandwereconfidentthatthatexperiencewouldstandusingoodstead.Thisprovedtrue,althoughwehadsomenewthingstolearn.Themostimportantofthesewasthattransientsmustbetreatedcorrectly;whatwouldcauseaharmlessflashonthescreenofatelevisionsetcouldleadtoaseriouserrorinacomputer.

Asfarascomputingcircuitswereconcerned,wefoundourselveswithanembarassderichess.Forexample,wecouldusevacuumtubediodesforgatesaswedidintheEDSACorpentodeswithcontrolsignalsonbothgrids,asystemwidelyusedelsewhere.Thissortofchoicepersistedandthetermfamiliesoflogiccameintouse.ThosewhohaveworkedinthecomputerfieldwillrememberTTL,ECLandCMOS.Ofthese,CMOShasnowbecomedominant.

Inthoseearlyyears,theIEEwasstilldominatedbypowerengineeringandwehadtofightanumberofmajorbattlesinordertogetradioengineeringalongwiththerapidlydevelopingsubjectofelectronics.dubbedintheIEElightcurrentelectricalengineering.properlyrecognisedasanactivityinitsownright.Irememberthatwehadsomedifficultyinorganisingaconferencebecausethepowerengineers’waysofdoingthingswerenotourways.AminorsourceofirritationwasthatallIEEpublishedpaperswereexpectedtostartwithalengthystatementofearlierpractice,somethingdifficulttodowhentherewasnoearlierpracticeConsolidationinthe1960s

Bythelate50sorearly1960s,theheroicpioneeringstagewasoverandthecomputerfieldwasstartingupinrealearnest.Thenumberofcomputersintheworldhadincreasedandtheyweremuchmorereliablethantheveryearlyones.Tothoseyearswecanascribethefirststepsinhighlevellanguagesandthefirstoperatingsystems.Experimentaltime-sharingwasbeginning,andultimatelycomputergraphicswastocomealong.

Aboveall,transistorsbegantoreplacevacuumtubes.Thischangepresentedaformidablechallengetotheengineersoftheday.Theyhadtoforgetwhattheyknewaboutcircuitsandstartagain.Itcanonlybesaidthattheymeasuredupsuperblywelltothechallengeandthatthechangecouldnothavegonemoresmoothly.

Soonitwasfoundpossibletoputmorethanonetransistoronthesamebitofsilicon,andthiswasthebeginningofintegratedcircuits.Astimewenton,asufficientlevelofintegrationwasreachedforonechiptoaccommodateenoughtransistorsforasmallnumberofgatesorflipflops.Thisledtoarangeofchipsknownasthe7400series.Thegatesandflipflopswereindependentofoneanotherandeachhaditsownpins.Theycouldbeconnectedbyoff-chipwiringtomakeacomputeroranythingelse.

Thesechipsmadeanewkindofcomputerpossible.Itwascalledaminicomputer.Itwassomethinglessthatamainframe,butstillverypowerful,andmuchmoreaffordable.Insteadofhavingoneexpensivemainframeforthewholeorganisation,abusinessorauniversitywasabletohaveaminicomputerforeachmajordepartment.

Beforelongminicomputersbegantospreadandbecomemorepowerful.Theworldwashungryforcomputingpowerandithadbeenveryfrustratingforindustrynottobeabletosupplyitonthescalerequiredandatareasonablecost.Minicomputerstransformedthesituation.

Thefallinthecostofcomputingdidnotstartwiththeminicomputer;ithadalwaysbeenthatway.ThiswaswhatImeantwhenIreferredinmyabstracttoinflationinthecomputerindustry‘goingtheotherway’.Astimegoesonpeoplegetmorefortheirmoney,notless.

ResearchinComputerHardware.

ThetimethatIamdescribingwasawonderfuloneforresearchincomputerhardware.Theuserofthe7400seriescouldworkatthegateandflip-floplevelandyettheoveralllevelofintegrationwassufficienttogiveadegreeofreliabilityfarabovethatofdiscreettransistors.Theresearcher,inauniversityorelsewhere,couldbuildanydigitaldevicethatafertileimaginationcouldconjureup.IntheComputerLaboratorywebuilttheCambridgeCAP,afull-scaleminicomputerwithfancycapabilitylogic.

The7400serieswasstillgoingstronginthemid1970sandwasusedfortheCambridgeRing,apioneeringwide-bandlocalareanetwork.PublicationofthedesignstudyfortheRingcamejustbeforetheannouncementoftheEthernet.Untilthesetwosystemsappeared,usershadmostlybeencontentwithteletype-basedlocalareanetworks.

Ringsneedhighreliabilitybecause,asthepulsesgorepeatedlyroundthering,theymustbecontinuallyamplifiedandregenerated.Itwasthehighreliabilityprovidedbythe7400seriesofchipsthatgaveusthecourageneededtoembarkontheprojectfortheCambridgeRing.

TheRISCMovementandItsAftermath

Earlycomputershadsimpleinstructionsets.Astimewentondesignersofcommerciallyavailablemachinesaddedadditionalfeatureswhichtheythoughtwouldimproveperformance.Fewcomparativemeasurementsweredoneandonthewholethechoiceoffeaturesdependeduponthedesigner’sintuition.

In1980,theRISCmovementthatwastochangeallthisbrokeontheworld.ThemovementopenedwithapaperbyPattersonandDitzelentitledTheCasefortheReducedInstructionsSetComputer.

Apartfromleadingtoastrikingacronym,thistitleconveyslittleoftheinsightsintoinstructionsetdesignwhichwentwiththeRISCmovement,inparticularthewayitfacilitatedpipelining,asystemwherebyseveralinstructionsmaybeindifferentstagesofexecutionwithintheprocessoratthesametime.Pipeliningwasnotnew,butitwasnewforsmallcomputers

TheRISCmovementbenefitedgreatlyfrommethodswhichhadrecentlybecomeavailableforestimatingtheperformancetobeexpectedfromacomputerdesignwithoutactuallyimplementingit.Irefertotheuseofapowerfulexistingcomputertosimulatethenewdesign.Bytheuseofsimulation,RISCadvocateswereabletopredictwithsomeconfidencethatagoodRISCdesignwouldbeabletoout-performthebestconventionalcomputersusingthesamecircuittechnology.Thispredictionwasultimatelybornoutinpractice.

Simulationmaderapidprogressandsooncameintouniversalusebycomputerdesigners.Inconsequence,computerdesignhasbecomemoreofa

scienceandlessofanart.Today,designersexpecttohavearoomfulof,computersavailabletodotheirsimulations,notjustone.Theyrefertosucharoomfulbytheattractivenameofcomputerfarm.

Thex86InstructionSet

Littleisnowheardofpre-RISCinstructionsetswithonemajorexception,namelythatoftheIntel8086anditsprogeny,collectivelyreferredtoasx86.ThishasbecomethedominantinstructionsetandtheRISCinstructionsetsthatoriginallyhadaconsiderablemeasureofsuccessarehavingtoputupahardfightforsurvival.

Thisdominanceofx86disappointspeoplelikemyselfwhocomefromtheresearchwings.bothacademicandindustrial.ofthecomputerfield.Nodoubt,businessconsiderationshavealottodowiththesurvivalofx86,butthereareotherreasonsaswell.Howevermuchweresearchorientedpeoplewouldliketothinkotherwise.highlevellanguageshavenotyeteliminatedtheuseofmachinecodealtogether.Weneedtokeepremindingourselvesthatthereismuchtobesaidforstrictbinarycompatibilitywithprevioususagewhenthatcanbeattained.Nevertheless,thingsmighthavebeendifferentifIntel’smajorattempttoproduceagoodRISCchiphadbeenmoresuccessful.Iamreferringtothei860（notthei960,whichwassomethingdifferent）.Inmanywaysthei860wasanexcellentchip,butitssoftwareinterfacedidnotfitittobeusedinaworkstation.

Thereisaninterestingstinginthetailofthisapparentlyeasytriumphofthex86instructionset.ItprovedimpossibletomatchthesteadilyincreasingspeedofRISCprocessorsbydirectimplementationofthex86instructionsetashadbeendoneinthepast.Instead,designerstookaleafoutoftheRISCbook;althoughitisnotobvious,onthesurface,amodernx86processorchipcontainshiddenwithinitaRISC-styleprocessorwithitsowninternalRISCcoding.Theincomingx86codeis,aftersuitablemassaging,convertedintothisinternalcodeandhandedovertotheRISCprocessorwherethecriticalexecutionisperformed.

InthissummingupoftheRISCmovement,IrelyheavilyonthelatesteditionofHennessyandPatterson’sbooksoncomputerdesignasmysupportingauthority;seeinparticularComputerArchitecture,thirdedition,2003,pp146,151-4,157-8.

4．外文资料译文

微机发展简史

EEE的论文剑桥大学，2004/2/5

莫里斯威尔克斯

计算机实验室

剑桥大学I

用第一台存储程序的计算开始出现于1950前后，它就是1949年夏天在剑桥大学，我们创造的延迟存储自动电子计算机（EDSAC）。

最初实验用的计算机是由象我一样有着广博知识的人构造的。

我们在电子工程方面都有着丰富的经验，并且我们深信这些经验对我们大有裨益。

后来，被证明是正确的，尽管我们也要学习很多新东西。

最重要的是瞬态一定要小心应付，虽然它只会在电视机的荧幕上一起一个无害的闪光，但是在计算机上这将导致一系列的错误。

在电路的设计过程中，我们经常陷入两难的境地。

举例来说，我可以使用真空二级管做为门电路，就象在EDSAC中一样，或者在两个栅格之间用带控制信号的五级管，这被广泛用于其他系统设计，这类的选择一直在持续着直到逻辑门电路开始应用。

在计算机领域工作的人都应该记得TTL，ECL和CMOS，到目前为止，CMOS已经占据了主导地位。

在最初的几年，IEE（电子工程师协会）仍然由动力工程占据主导地位。

为了让IEE认识到无线工程和快速发展的电子工程并行发展是它自己的一项权利，我们不得不面对一些障碍。

由于动力工程师们做事的方式与我们不同，我们也遇到了许多困难。

让人有些愤怒的是，所有的IEE出版的论文都被期望以冗长的早期研究的陈述开头，无非是些在早期阶段由于没有太多经验而遇到的困难之类的陈述。

60年代的巩固阶段

60年代初，个人英雄时代结束了，计算机真正引起了重视。

世界上的计算机数量已经增加了许多，并且性能比以前更加可靠。

这些我认为归因与高级语言的起步和第一个操作系统的诞生。

分时系统开始起步，并且计算机图形学随之而来。

综上所述，晶体管开始代替正空管。

这个变化对当时的工程师们是个不可回避的挑战。

他们必须忘记他们熟悉的电路重新开始。

只能说他们鼓起勇气接受了挑战，尽管这个转变并不会一帆风顺。

小规模集成电路和小型机

很快，在一个硅片上可以放不止一个晶体管，由此集成电路诞生了。

随着时间的推移，一个片子能够容纳的最大数量的晶体管