electroniccomponents
Thefourth-generationelectroniccomputerisbasedonlarge-scale,ultra-large-scaleintegratedcircuitsElectroniccomponent.
Fourth-generationfeatures
Thefourth-generationcomputerreferstotheuseoflarge-scaleintegratedcircuits(LSI)andverylarge-scaleintegratedcircuits(VLSI)asthemainelectronicdevicessince1970computer.Forexample,the80386microprocessorcanintegrateabout320,000transistorsonasinglechipwithanareaofabout10mmX10mm.
Anotherimportantbranchofthefourth-generationcomputerismicroprocessorsandmicrocomputersdevelopedonthebasisoflarge-scaleandverylarge-scaleintegratedcircuits.
Fourstages
Thefirststagewasfrom1971to1973,andtherewere4004,4040,and8008microprocessors.In1971,IntelCorporationdevelopedtheMCS4microcomputer(CPU4040,four-bitcomputer).Later,theMCS-8modelwith8008asthecorewasintroduced.
Thesecondstageisthedevelopmentandimprovementstageofmicrocomputersfrom1973to1977.Thereare8080,8085,M6800,Z80microprocessors.TheinitialproductisIntel'sMCS-80type(CPU8080,eight-bitcomputer).Inthelaterperiod,therewereTRS-80type(CPUisZ80)andAPPLE-IItype(CPUis6502),whichonceswepttheworldintheearly1980s.
Thethirdstageisthedevelopmentstageof16-bitmicrocomputersfrom1978to1983.Thereare8086,8088,80186,80286,M68000,Z8000microprocessors.TherepresentativeproductofmicrocomputerisIBM-PC(CPUis8086).ThepinnacleproductsofthisstageareApple’sMacintosh(1984)andIBM’sPC/AT286(1986)microcomputer.
Thefourthstageisthedevelopmentstageof32-bitmicrocomputersstartingin1983.Microprocessorshavesuccessivelyintroduced80386and80486.386and486microcomputersaretheinitialproducts.In1993,IntelintroducedthePentiumorP5(Chinesetranslationfor"Pentium")microprocessor,whichhasa64-bitinternaldatachannel.PentiumIII(alsocalledP7)microprocessorshavebecomemainstreamproducts,andPentiumIVwaslaunchedinOctober2000.
Itcanbeseenthattheperformanceofamicrocomputermainlydependsontheperformanceofitscoredevice-themicroprocessor(CPU).
Emergenceanddevelopment
TheemergenceanddevelopmentofmicrocomputersthatcondenseCPUsonachipsetoffawaveofpopularizationofcomputers.In1969,Intelwascommissionedtodesignacompletecircuitforacalculator.FedericoFagin,ayoungengineerofthecompany,successfullyintegrated2,250transistorsona4.2×3.2siliconwafer.Thisisthefirstmicroprocessor-Intel4004.Itis4bits.Afterit,the8-bitmicroprocessorIntel8008wasborninearly1972.Thesecondgenerationofmicroprocessors(8-bit)appearedin1973,suchasIntel8080(1973),M6800(1975,MstandsforMotorola),Z80(1976,ZstandsforZilogCompany)andsoon.In1978,thethirdgenerationofmicroprocessors(16bits)appeared,suchasIntel8086,Z8000,M68000andsoon.In1981,thefourthgenerationofmicroprocessors(32-bit)appeared,suchasiAPX432,i80386,MAC-32,NS-16032,Z80000,HP-32,etc.Theirperformanceisroughlycomparabletothatoflargeandmedium-sizedcomputersinthe1970s.Themicroprocessor'sspeedofchangingfromonegenerationtoanotherintwoorthreeyearsisunmatchedbyanytechnology.
Computer
OneoftheearliestpersonalcomputerswastheAppleIIcomputerfromAppleInc.,whichwassoldonthemarketin1977.FollowedbyTRS-80(RadioShack)andPET-2001(Commodore).Sincethen,variouspersonalcomputershavesprungup.Personalcomputersatthattimeweregenerallybasedon8-bitor16-bitmicroprocessorchips,withastoragecapacityof64KBormore,withinputandoutputdevicessuchaskeyboardsandmonitors,andcouldbeequippedwithperipheraldevicessuchassmallprinters,floppydisks,andcartridges.Youcanuseavarietyofhigh-levellanguageself-programming.
WiththecontinuouspopularizationofPCs,IBMalsoorganizedapersonalcomputerdevelopmentteaminAugust1979.Twoyearslater,theIBM-PCwasannounced,andtheexpansionmodelIBM-PC/XTwasintroducedin1983,whichcausedagreatshockinthecomputerindustry.Atthattime,IBMpersonalcomputershadaseriesofcharacteristics:advanceddesign(usingIntel8088microprocessor),richsoftware(morethan800companiesuseitasastandardtopreparesoftware),completefunctions(strongcommunicationability,andcanbeconnectedtomainframes)),thepriceischeap(productionishighlyautomated,thecostisverylow).By1983,IBM-PCquicklyoccupiedthemarketandreplacedApple,whichwasknownasthekingofmicrocomputersintheUnitedStates.