Introduction
Microcomputerisabbreviatedasmicrocomputer,commonlyknownascomputer,anditsaccuratenameshouldbemicrocomputersystem.Itcanbesimplydefinedasanentitycomposedofnecessaryexternalequipmentandsoftwareonthebasisofamicrocomputerhardwaresystem.
Composition
Therearethreelevelsofmicrocomputersystemfromglobaltolocal:microcomputersystem,microcomputer,andmicroprocessor(CPU).Neitherasimplemicroprocessornorasimplemicrocomputercanworkindependently.Onlyamicrocomputersystemisacompleteinformationprocessingsystemandhaspracticalsignificance.
Acompletemicrocomputersystemincludestwoparts:hardwaresystemandsoftwaresystem.Thehardwaresystemiscomposedofarithmeticunit,controller,memory(includingmemory,externalmemoryandcache),andvariousinputandoutputdevices,anditworksina"command-driven"mode.
Thesoftwaresystemcanbedividedintosystemsoftwareandapplicationsoftware.Systemsoftwarereferstosoftwarethatmanages,monitors,andmaintainscomputerresources(includinghardwareandsoftware).Itmainlyincludes:operatingsystem,variouslanguageprocessingprograms,databasemanagementsystemandvarioustoolsandsoftware.Theoperatingsystemisthecoreofthesystemsoftware,andonlythroughtheoperatingsystemcanuserscompletevariousoperationsonthecomputer.Applicationsoftwareisacomputerprogrampreparedforacertainapplicationpurpose,suchaswordprocessingsoftware,graphicsandimageprocessingsoftware,networkcommunicationsoftware,financialmanagementsoftware,CADsoftware,variousprogrampackages,etc.
Features
Thefeaturesofmicrocomputersaresmallsize,highflexibility,lowprice,andeasytouse.SinceIBMlaunchedthefirst-generationmicrocomputerIBM-PCin1981,themicrocomputerhasquicklyenteredvariousfieldsofsocietywithitspreciseexecutionresults,fastprocessingspeed,highcostperformance,lightweightandcompactness,andthetechnologyisconstantlyupdatedandtheproductsarequicklyreplaced.,Fromasimplecomputingtooltoapowerfulmultimediatoolcapableofprocessingmultipleinformationsuchasnumbers,symbols,text,language,graphics,images,audio,andvideo.Today'smicrocomputerproductshavemadeagreatleapovertheearlierproductsintermsofcomputingspeed,multimediafunctions,softwareandhardwaresupport,andeaseofuse.
Classification
Workstation
Workstationisahigh-endgeneral-purposemicrocomputer,basedonpersonalcomputersanddistributednetworkcomputing,mainlyforprofessionalapplications.Withpowerfuldatacomputing,graphics,andimageprocessingcapabilities,itisahigh-performancecomputerdesignedanddevelopedtomeetprofessionalfieldssuchasengineeringdesign,animationproduction,scientificresearch,softwaredevelopment,financialmanagement,informationservices,andsimulation.Itbelongstoahigh-endcomputer,generallyhasalargescreendisplayandlarge-capacitymemoryandharddisk,butalsohasstronginformationprocessingfunctionsandhigh-performancegraphics,imageprocessingfunctionsandnetworkingfunctions.
Server
Serverrefersspecificallytocertainhigh-performancecomputersthatcanprovideexternalservicesthroughtheInternet.Comparedwithordinarycomputers,stability,security,performanceandotheraspectsaremoredemanding,sotheCPU,chipset,memory,disksystem,networkandotherhardwarearedifferentfromordinarycomputers.Theserveristhenodeofthenetwork,storingandprocessing80%ofthedataandinformationonthenetwork,andplaysadecisiveroleinthenetwork.Aserverisahigh-performancecomputerthatprovidesvariousservicestoclientcomputers.Itshighperformanceismainlymanifestedinhigh-speedcomputingpower,long-termreliableoperation,andpowerfulexternaldatathroughputcapabilities.Thestructureoftheserverissimilartothatofanordinarycomputer.Therearealsoprocessors,harddisks,memory,systembuses,etc.,butbecauseitisspeciallycustomizedforspecificnetworkapplications,serversandmicrocomputersareintermsofprocessingcapacity,stability,reliability,andsecurity.Therearebigdifferencesintermsof,scalability,andmanageability.Serversmainlyincludenetworkservers(DNS,DHCP),printservers,terminalservers,diskservers,mailservers,fileservers,etc.
Industrialcontrolcomputer
Industrialcontrolcomputerisageneraltermforacomputersystemthatusesabusstructuretodetectandcontroltheproductionprocessanditselectromechanicalequipmentandprocessequipment,referredtoascontrolmachine.Itconsistsoftwoparts:computerandprocessinput/output(I/O).Thecomputerconsistsofahost,input/outputdevices,externaldiskdrives,tapedrives,andsoon.Apartoftheprocessinput/outputchannelsareaddedoutsidethecomputertosendtheinspectiondataoftheindustrialproductionprocesstothecomputerforprocessing;ontheotherhand,thecomputermustexercisethecontrolcommandsandinformationoftheproductionprocesstoconvertthecontroloftheindustrialcontrolobjectThevariablesignalissenttothecontrolleroftheindustrialcontrolobject.Thecontrollerexercisestheoperationcontroloftheproductionequipment.
Personalcomputer
①Desktop:Adesktopcomputerisaverywidelyusedmicrocomputer,alsocalledadesktopcomputer.Itisanindependentandseparatedcomputerwitharelativelylargevolume.Devicessuchasmonitorsaregenerallyrelativelyindependentandneedtobeplacedonacomputerdeskoraspecialworkbench,sotheyarenameddesktops.Thedesktopchassishasalargespace,goodventilation,andgoodheatdissipation;anindependentchassisfacilitatesuserstoupgradehardware,suchasopticaldrivesandharddrives;thedesktopchassis’son-offkey,restartbutton,USB,andaudiointerfacesareallinfrontofthechassisInthepanel,itisconvenientforuserstouse.
②Computerall-in-one:Acomputerall-in-oneisacomputercomposedofamonitor,akeyboardandamouse.Itschip,motherboardandmonitorareintegratedtogether.Themonitorisacomputer,soaslongasthekeyboardandmouseareconnectedtothemonitor,themachinecanbeused.Withthedevelopmentofwirelesstechnology,thekeyboard,mouse,anddisplayoftheall-in-onecomputercanbeconnectedwirelessly.Themachinehasonlyonepowercord,whichlargelysolvestheproblemofmanyandcomplicateddesktopcablesthathavebeencriticized.
③Notebookcomputer:Anotebookcomputerisasmall,portablepersonalcomputer,usuallywithamassof1-3kg.Itissimilartothedesktoparchitecture,butithasbetterportability.Inadditiontothekeyboard,thenotebookcomputeralsoprovidesatouchpad(TouchPad)oratouchpoint(PointingStick),whichprovidesbetterpositioningandinputfunctions.
④Handheldcomputer(PDA):PDA(PersonalDigitalAssistant),whichmeanspersonaldigitalassistant.Asthenamesuggests,itisadigitaltooltoassistindividualsintheirwork,mainlyprovidingfunctionssuchasnotes,addressbook,businesscardexchange,anditineraryarrangement.Itcanhelppeoplework,study,entertain,etc.onthemove.Classifiedbyuse,itisdividedintoindustrialgradePDAandconsumerPDA.Industrial-gradePDAsaremainlyusedintheindustrialfield,suchasbarcodescanners,RFIDreaders,POSmachines,etc.;consumerPDAsincludemore,suchassmartphones,handheldgameconsoles,etc.
⑤TabletPC:TabletPCisalsocalledTabletPersonalComputer(TabletPc,FlatPc,Tablet,Slatesforshort).Itisasmall,portablepersonalcomputerwithatouchscreenasthebasicInputdevice.Ithasatouchscreen(alsoknownastablettechnology)thatallowsuserstoperformtaskswithastylusordigitalpeninsteadofatraditionalkeyboardormouse.Userscaninputthroughthebuilt-inhandwritingrecognition,on-screensoftkeyboard,voicerecognitionorarealkeyboard(ifthemodelisequipped).
Embeddedcomputer
Personalcomputer(3photos)
Embeddedcomputerisanembeddedsystem,whichisanapplication-centric,Adedicatedcomputersystembasedonamicroprocessor,softwareandhardwarethatcanbetailored,andadaptedtotheapplicationsystem'scomprehensiveandstrictrequirementsonfunctions,reliability,cost,volume,andpowerconsumption.Itisgenerallycomposedoffourparts:embeddedmicroprocessor,peripheralhardwareequipment,embeddedoperatingsystemanduser'sapplicationprogram.Itisthefastestgrowingfieldinthecomputermarket,anditisalsoawidevarietyofcomputersystemsinvariousforms.Embeddedsystemsincludealmostallelectricalequipmentinlife,suchascalculators,TVset-topboxes,mobilephones,digitalTVs,multimediaplayers,cars,microwaveovens,digitalcameras,homeautomationsystems,elevators,airconditioning,securitysystems,andvendingmachines,Consumerelectronicsequipment,industrialautomationinstrumentsandmedicalinstruments,etc.Developmentstage
1,4-bitand8-bitlow-endmicroprocessorera(1971~1973)
January1971,IntelThecompany’sHoffengineerssuccessfullydevelopedtheworld’sfirst4-bitmicroprocessorchipIntel4004,markingtheadventofthefirstgenerationofmicroprocessorsandthebeginningofthemicrocomputerera.
Thisstageistheeraof4-bitand8-bitlow-endmicroprocessors,usuallycalledthefirstgeneration.ItstypicalproductsareIntel4004andIntel8008microprocessorsandMCS-4andMCS-8microcomputer.ThebasiccharacteristicsoftheproductsatthisstagearetheuseofPMOStechnology,lowintegration,relativelysimplesystemstructureandinstructionsystem,mainlyusingmachinelanguageorsimpleassemblylanguage,withasmallnumberofinstructions,andaremostlyusedinhomeappliancesandsimplecontroloccasions.
2,8-bithigh-endmicroprocessorera(1974~1978)
Thisstageisusuallycalledthesecondgeneration.TypicalproductsincludeIntelThecompany’sIntel8080/8085,Motorola’sMC6800andAmericanZilog’sZ80,etc.,aswellasvarious8-bitmicrocontrollers,suchasInte’s8048,Motorola’sMC6801,andZilog’sZ8.ThebasiccharacteristicsoftheproductsatthisstagearetheuseofNMOStechnology,theintegrationdegreeisincreasedbyabout4times,thecalculationspeedisincreasedbyabout10to15times,theinstructionsystemisrelativelycomplete,andithasatypicalcomputerarchitectureandcontrolfunctionssuchasinterruptandDMA.Inadditiontoassemblylanguageinsoftware,therearealsohigh-levellanguagessuchasBASICandFORTRANandcorrespondinginterpretersandcompilers.Inthelaterstage,operatingsystemsalsoappeared,suchasCP/M,whichwasthepopularoperatingsystematthattime.
3,16-bitmicroprocessorera(1978~1984)
Thisstageisusuallycalledthethirdgeneration.InJune1978,IntelintroducedtheIntel8086,amicroprocessorchipwitha16-bitwordlengthof4.77MHz.Thebirthofthe8086microprocessormarkedtheadventofthethirdgenerationofmicroprocessors.TypicalproductsatthisstageincludeIntel’s8086/8088,80286,Motorola’sM68000,Zilog’sZ8000andothermicroprocessors.ItischaracterizedbytheuseofHMOStechnology,andtheintegrationandoperationspeedarebothanorderofmagnitudehigherthanthatofthesecondgeneration.Theinstructionsystemisricherandmorecomplete,usingmulti-levelinterrupts,multipleaddressingmethods,segmentstoragestructure,hardwaremultiplicationanddivisioncomponents,andasoftwaresystem.
ThefamouspersonalcomputerproductofthisperiodisthepersonalcomputerPCofIBM.TheIBM-PClaunchedin1981uses8088CPU.Thenin1982,anexpandedpersonalcomputerIBM-PC/XTwasintroduced,whichexpandedthememoryandaddedaharddiskdrive.In1984,IBMintroducedtheIBM-PC/AT,a16-bitenhancedpersonalcomputerwith80286processorasthecore.BecauseIBMadoptedatechnologyopenstrategywhendevelopingPCs,PCsbecamepopularallovertheworld.
4,32-bitmicroprocessorera(1985~1992)
Thisstageisusuallycalledthe4thgeneration.InOctober1985,IntelCorporationintroducedthe80386DXmicroprocessor,whichmarkedthebeginningoftheeraofa32-bitdatabus.TypicalproductsatthisstageincludeIntel’s80386/80486,Motorola’sM68030/68040andsoon.ItischaracterizedbytheuseofHMOSorCMOStechnology,theintegrationlevelisupto1milliontransistors/chip,andithasa32-bitaddresslineanda32-bitdatabus.Itcancomplete6millioninstructionspersecond.Thefunctionofthemicrocomputerhasreachedorevensurpassedthesuperminicomputer,whichisfullycapableofmulti-taskingandmulti-useroperations.Inthesameperiod,someothermicroprocessormanufacturers(suchasAMD,TEXAS,etc.)alsolaunched80386/80486seriesofchips.
5.TheeraofPentiumseriesmicroprocessors(after1993)
Thisstageisusuallycalledthe5thgeneration.TypicalproductsareIntel’sPentiumserieschipsandAMD’sK6seriesmicroprocessorchipscompatiblewithit.Inthisstage,theproductadoptsasuperscalarinstructionpipelinestructureandhasindependentinstructionanddatacaches.WiththeemergenceofMMX(MultimediaeXtended)microprocessors,thedevelopmentofmicrocomputershasreachedahigherlevelintermsofnetworking,multimediaandintelligence.InMarch2000,AMDandIntelrespectivelylaunchedAthlonandPentiumⅢwithclockfrequenciesupto1GHz.InNovember2000,IntelintroducedthePentiumⅣmicroprocessor,withanintegrationlevelofupto42milliontransistorsperchip,a1.5GHzfrequency,a400MHzfront-sidebus,andanewSSE2instructionset.InNovember2002,theclockfrequencyofIntel'sPentiumⅣmicroprocessorreached3.06GHz,andthemicroprocessorisstillbeingdevelopedanditsperformanceisconstantlyimproving.
In2001,Intelreleaseditsfirst64-bitproduct,Itanium(Itanium)microprocessor.InApril2003,AMDintroducedtheOpteronmicroprocessorbasedon64-bitcomputing.InSeptember2003,AMD'sAthlon(Athlon)microprocessorcameout,markingthearrivalofthe64-bitcomputingera.
Technicalindicators
Computerperformanceindicatorsinvolvemultiplefactorssuchasarchitecture,hardwareandsoftwareconfiguration,commandsystem,etc.Generallyspeaking,thefollowingtechnicalindicatorsarethemainones.
Wordlength
Wordlengthreferstothenumberofbitsofbinarydatathatthecomputerarithmeticunitcanprocessatonetime.Thelongerthewordlength,ifusedtostoredata,thehigherthecomputer'sarithmeticaccuracy;ifusedasstorageinstructions,thecomputer'sprocessingpowerwillbestronger.Usuallythewordlengthisalwaysanintegermultipleof8,suchas8,16,32,64bitsandsoon.BothIntel486machinesandPentium4machinesare32-bitmachines.
Clockfrequency
ClockfrequencyreferstotheclockfrequencyoftheCPU,anditsleveldeterminesthecomputerspeedtoacertainextent.Themainfrequencyisinmegahertz(MHz).Generallyspeaking,thehigherthemainfrequency,thefasterthespeed.Duetotherapiddevelopmentofmicroprocessors,themainfrequencyofmicrocomputersisalsoincreasing.
Computationalspeed
Thecomputationalspeedofacomputerusuallyreferstothenumberofinstructionsthatcanbeexecutedpersecond,usuallyexpressedinmillionsoftimespersecond(MIPS,MillionInstructionsPerSecond).Thisindicatorcanmoreintuitivelyreflectthespeedofthemachine.
Storagecapacity
Storagecapacityisusuallydividedintomemorycapacityandexternalmemorycapacity,heremainlyreferstothecapacityofinternalmemory.Obviously,thelargerthememorycapacity,thelargertheprogramthatthemachinecanrun,andthestrongertheprocessingpower.Inparticular,thecurrentmultimediaPCapplicationsmostlyinvolveimageinformationprocessing,requiringmoreandmorestoragecapacity,andevenwithoutalargeenoughmemorycapacity,itisimpossibletoruncertainsoftware.Atpresent,thememorycapacityofmostmicrocomputershasreached4GB.
Accesscycle
Theaccesscycleofinternalmemoryisalsooneofthemainindicatorsthataffecttheperformanceoftheentirecomputersystem.Simplyput,theaccesscycleisthetimerequiredfortheCPUtoaccessdatafromtheinternalmemory.Atpresent,thememoryaccesscycleisbetween7-70ns.
Inaddition,thereliability,maintainability,meantimebetweenfailures,andperformance-priceratioofcomputersarealsotechnicalindicatorsofcomputers.