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,IntroductionandDevelopmentofComputer,UNITTWO,LessonOnetheCentralProcessingUnitLessonTwoIntroductionofMemoryLessonThreeInput/Outputdevices,LessonOnetheCentralProcessingUnit,TheCPUstandsforCentralProcessingUnit.TheCPUcoordinatesalltheactivitiesofthevariouscomponentsofthecomputer.Itdetermineswhichoperationsshouldbecarriedoutandinwhatorder.TheCPUcanalsoretrieveinformationformmemoryandstoretheresultsofmanipulationsbackintothememoryunitforlaterreference.,coordinatevt.调整，整理activityn.活跃，行动variousadj.各种各样的determinev.决定，确定operationn.操作，运转carryout执行ordern.顺序，命令；v.命令retrieven.找回；v.重新得到referencen.提及，参考,Theprocessorcontainsfourkeycomponents:aclock,aninstructioncontrolunit,anarithmeticandlogicunit,andasetofregisters.ThespeedatwhichtheCPUoperatesiscalledtheclockspeedandismeasuredinmegahertz(MHz).AclockcycleisthetimethattheCPUtakestoperforminstructionsatagivenclockspeed.Clockcyclesaremeasuredinnanoseconds(ns).,aclock一个时钟instructioncontrolunit指令控制单元arithmeticandlogicunit算术逻辑单元register寄存器megahertz兆赫clockcycle时钟周期Nanoseconds纳秒,Thearithmeticandlogicunitexecutesthatinstruction.Itconsistsofthecircuitsthatadd,subtract,multiply,divide,compare,copy,andinitiateinputoroutputthecomputersinstructionset.Registersaretemporarystoragedevicesthatholdcontrolinformation,keydata,andintermediateresults.,Subtract减去Multiply乘，繁殖Divide除Compare比较initiate开始intermediateresult中间结果,WhenyoubuyaPCoraCPU,youmustpayattentiontosomeindexesoftheCPU.Mainfrequencyorinternalfrequency:Externalfrequency:CPUratio:,1.Askingawomansageisimpoliteinmycountry.在我们国家，问女士的年龄不礼貌的。2.Meetingnewpeoplemakesmenervous.与陌生人见面使我很紧张。3.Workinghardwillproducegoodresults.努力工作将产生好结果。4.Makingmoneyiseverybodysdream.赚钱是每个人的梦想。5.Complainingdoesntsolveproblems.抱怨解决不了问题。6.Fallinginloveiseasy.Stayinginloveishard.一见钟情很容易，长相厮守很难。,英语口语练习材料,Thetermmemoryisusuallyusedtorefertotheinternalstoragelocationsofacomputer.Itisalsocalledrealstorageorprimarymemory,andisexpressedasquantitiesofK.EachKisequalto1,024bytes,andeachbyteisequalto8bits.Themicrocomputersmemoryconsistsofmainmemoryandsecondarystorage.,LessonTwoIntroductionofMemory,MainmemoryThemainmemoryofmostcomputersiscomposedofrandomaccessmemory,orRAM.InputdatacanbestoredinRAM,destroyingtheoldcontentsoftheselectedbytesofwords,oncetheresultswrittentoothermemorylocations.Finally,thecontentscanbesenttoanoutputdevice.Whenaprogramisfinished,anewprogramcanbecopiedintoRAMareeasytochange.,destroyv.破坏，毁坏contentn.内容；adj.满足的；vt.使满足locationn.位置，场所changen.改变，转变；vt.改变，改造,MainmemoryUsually,RAMsflexibilityisanadvantage.Occasionally,however,itcanbeaproblem.Thebankneedsaprogramthatcanbereadbytheprocessor,butnotmodified.Suchprogramsarestoredinreadonlymemory,orROM.Asthenameimplies,ROMis“permanent”memorythatcanberead,butnotwritten.,Occasionallyasthenameimply,adv.有时候，偶而,顾名思义,SecondarystorageMainmemoryisexpensive,andthesupplyonmostmachinedislimited.Anotherproblemisitsvolatility;mainmemorylosesitscontentswhenitspoweriscutwhenthecomputeristurnedoff.Thereforeweneedafast,accurate,inexpensive,high-capacity,non-volatileextensionofmainmemory,andsecondarystoragefillsthisneed.,volatilityaccurateinexpensive,n.挥发性,adj.正确的，精确的,adj.便宜的,magneticcassettefloppydiskdisketteharddisk,recordmusic,Datastoredonharddiskcanbeaccessedfarmorerapidlythandatastoredondiskette.,Anotheradvantageofharddiskisitsstoragecapacity.,优盘OnlyDisk：USB接口、无需驱动器的高容量存储设备，如图所示。其特点是体积小、重量轻，容量较大（16MB、32MB、64MB、128MB2GB）、存取速度较快，价格比较便宜，已在逐步取代软盘。,移动硬盘：USB接口的可携带的硬盘，具有固定硬盘的基本特征，如图。容量520GB，价格比较昂贵。,Doyouknowmywork?Onenightahotelcaughtfire,andthepeoplewhowerestayinginitranoutintheirnightclothes.Twomenstoodoutsideandlookedatthefire.“BeforeIcameout,”saidone,“Iranintosomeoftheroomsandfoundalotofmoney.Peopledontthinkofmoneywhentheyreafraid.Whenanyoneleavespapermoneyinafire,thefireburnsit.SoItookallthebillsthatIcouldfind.NoonewillbepoorerbecauseItookthem.”,英语幽默笑话,“Youdontknowmywork,”saidtheother.“whatisyourwork?”“Imapoliceman.”“Oh!”criedthefirstman.Hethoughtquicklyandsaid,“anddoyouknowmywork?”“No,”saidthepoliceman.“Imawriter,Imalwaystellingstoriesaboutthingsthatneverhappened.”,Acomputerisamachinethatprocessesdataintoinformation.Unlesssomehumanbeingneedstheinformation,thereisnopointtoprocessingthedata.Withoutdata,thereisnothingtoprocess.Inputandoutputdevicesprovideameansforpeopletoaccessacomputer.,LessonThreeInput/Outputdevices,Inputdevices,ThemessageorsignalsreceivedareencodedintopatternswhichCPUcanprocessbyinputdevices,then,conveyedtoCPU.Thebasicinputdeviceonmostsmallcomputersystemsisakeyboard.signalreceiveencodepatternconvey,n.信号adj.信号的v.发信号,v.收到受到接待,vt.编码,n.式样，图案v.模仿，仿造,vt.搬运传达转让,Thekeyboardhasletterkeys,punctuationkeys,andaspacebar.Italsohasfunction,numeric,andarrowkeys.,OutputDevices,OutputDevices,Outputdevicesalsoplayimportantrolesinacomputersystem.Theycantelltheprocessingresultsandwarnuserswheretheirprogramsoroperationsarewrong.Themostcommonoutputdevicesaremonitor,impactprinter,inkjetprinter,laserprinter,plotterfordrawing,speaker,etc.,Whichparametersorindexesoughttobepaidattentiontowhenyouselectamonitor?Weprovidesomehereforyourreference.ElementDistance像素距离VideoBandwidth视频带宽VerticalScanRateandHorizontalScanFrequency垂直扫描率和水平扫描率Solution分辨率,n.提及，参考,Printedoutput,whichcanbereadbyhumansratherthanbyacomputer,isthemostcommonoutput.Itistwo-dimensional,consistingofcharacterswithinaline,andlinesonapage.Theimagedisplayedonascreenistemporary;itfadesassoonasthepoweriscut.Byroutingtheoutputtoaprinter,apermanentcopy(calledahardcopy)isobtained.,two-dimensional两维的consistof由组成charactern.特征，字符；vt.使具有特征linen.绳,线路；vt.排成一行；vi.排队pagen.页；v.翻书页imagen.图像；vt.想象Temporary暂时的，临时的assoonas一就permanent永久的,installSatisfyconditiontemperaturehumidityrangemagnet,blindcurtainprotectsunlightvehicleambientgenerate,suddenlyfieldsubjectshockvibrationsurfacedust,accumulationpreventproperlyremovecartridgereplacedink,Makesuretheplacewheretheprinterisinstalledsatisfiesthefollowingconditions.Usetheprinteronlywiththefollowingtemperatureandhumidityranges.Ambienttemperature:5to35Ambienthumidity:10%to90%,Wheninstallednearawindow,putupablindorcurtaintoprotecttheprinterfromsunlight.Donotleavetheprinterinavehiclebecausethetemperaturecansuddenlyrisethere.Donotinstalltheprinterneardeviceswhichcontainmagnetsorgeneratemagneticfields.Donotsubjecttheprintertostrongphysicalshockorvibration.,Placetheprinteronalevelsurface.Keeptheprinterclean.Dustaccumulationscanpreventtheprinterfromoperatingproperly.Donotplaceobjectsontopoftheprinter.Donotremovethecartridgefromtheprinteruntilithastobereplaced.Thecartridgewillnotprintbecauseofinkdryingout.,Singlechoice.Thebasicinputdeviceonasmallcomputerisa.a.displayscreenb.printerd.cardreaderThebasicoutputdeviceonasmallcomputerisa.a.keyboardc.disketted.plotterAgenerateshard-copyoutput.a.displayunitb.screenc.monitorAdisplayscreenisdividedintoagridof.a.bytesb.bitsd.wordsExternaldevicesarelinkedtoasmallcomputersystemthrough.a.channelsb.controlunitsc.plugs,b.displayscreen,c.keyboard,d.printer,c.pixels,d.interfaces,
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