計算機硬件是計算機運行所需要的設(shè)備-由可進行物理處理的元件組成

ComputerEnglishIUnitTwoComputerArchitecture1SectionAIntroductionInputHardwareOutputHardwareStorageHardwareHardwareConnections2I.IntroductionComputerhardwareistheequipmentinvolvedinthefunctionofacomputerandconsistsofthecomponentsthatcanbephysicallyhandled.Thefunctionofthesecomponentsistypicallydividedintothreemaincategories:input,output,andstorage.計算機硬件是計算機運行所須要的設(shè)備，由可進行物理處理的元件組成。這些元件的功能一般分為3個主要類別：輸入、輸出和存儲。3I.IntroductionComponentsinthesecategoriesconnecttomicroprocessors,specifically,thecomputer’scentralprocessingunit(CPU),theelectroniccircuitrythatprovidesthecomputationalabilityandcontrolofthecomputer,viawiresorcircuitrycalledabus.這些類別的元件與微處理器相連接，特殊是與計算機的中心處理器相連接，而后者是通過被稱之為總線的線路或電路來供應(yīng)計算實力和對計算機進行限制的電子電路。4I.IntroductionSoftware,ontheotherhand,isthesetofinstructionsacomputerusestomanipulatedata,suchasaword-processingprogramoravideogame.Theseprogramsareusuallystoredandtransferredviathecomputer’shardwaretoandfromtheCPU.另一方面，軟件是計算機用來處理數(shù)據(jù)的一套指令，如字處理程序或者視頻游戲。這些程序通常被存儲起來，并由計算機硬件調(diào)入和調(diào)出中心處理器。5I.IntroductionSoftwarealsogovernshowthehardwareisutilized;forexample,howinformationisretrievedfromastoragedevice.TheinteractionbetweentheinputandoutputhardwareiscontrolledbysoftwarecalledtheBasicInputOutputSystem(BIOS)software.軟件也限制著硬件如何運用；例如，如何從存儲設(shè)備中檢索信息。輸入與輸出硬件的交互作用是由基本輸入輸出系統(tǒng)（BIOS）軟件限制的。6I.IntroductionAlthoughmicroprocessorsarestilltechnicallyconsideredtobehardware,portionsoftheirfunctionarealsoassociatedwithcomputersoftware.Sincemicroprocessorshavebothhardwareandsoftwareaspectstheyarethereforeoftenreferredtoasfirmware.盡管微處理器在技術(shù)上仍被認為是硬件，其部分功能也與計算機軟件有關(guān)系。既然微處理器同時具有硬件與軟件方面的特征，它們因此常常被稱作固件。7II.InputHardwareInputhardwareconsistsofexternaldevices——thatis,componentsoutsideofthecomputer’sCPU——thatprovideinformationandinstructionstothecomputer.Alightpenisastyluswithalightsensitivetipthatisusedtodrawdirectlyonacomputer’svideoscreenortoselectinformationonthescreenbypressingaclipinthelightpenorbypressingthelightpenagainstthesurfaceofthescreen.Thepencontainslightsensorsthatidentifywhichportionofthescreenitispassedover.輸入硬件由給計算機供應(yīng)信息和指令的外部設(shè)備——亦即計算機中心處理器以外的元件——組成。光筆是具有光敏端頭的輸入筆，用來在計算機屏幕上干脆寫畫，或者通過按光筆上的夾子或用光筆接觸屏幕來在屏幕上選擇信息。這種筆含有光傳感器，能夠識別屏幕上筆經(jīng)過的部分。8II.InputHardwareAmouseisapointingdevicedesignedtobegrippedbyonehand.Ithasadetectiondevice(usuallyaball)onthebottomthatenablestheusertocontrolthemotionofanon-screenpointer,orcursor,bymovingthemouseonaflatsurface.Asthedevicemovesacrossthesurface,thecursormovesacrossthescreen.Toselectitemsorchoosecommandsonthescreen,theuserpressesabuttononthemouse.鼠標是為一只手抓握而設(shè)計的指示設(shè)備。它在底部有一個檢測裝置（通常是一個圓球），運用戶通過在一個平面上移動鼠標能夠限制屏幕上指針或光標的運動。當鼠標滑過平面的時候，光標隨著在屏幕上移動。要在屏幕上選擇項目或吩咐，用戶就點擊鼠標上的按鈕。9II.InputHardwareAjoystickisapointingdevicecomposedofaleverthatmovesinmultipledirectionstonavigateacursororothergraphicalobjectonacomputerscreen.Akeyboardisatypewriter-likedevicethatallowstheusertotypeintextandcommandstothecomputer.Somekeyboardshavespecialfunctionkeysorintegratedpointingdevices,suchasatrackballortouch-sensitiveregionsthatlettheuser’sfingermotionsmoveanon-screencursor.操縱桿是由一根桿子組成的指示設(shè)備，該桿以向多個方向移動來操縱計算機屏幕上的光標或者其他圖形對象。鍵盤是一個像打字機的設(shè)備，它運用戶得以向計算機鍵入文本和吩咐。有些鍵盤有特殊功能鍵或集成的指示設(shè)備，如軌跡球或者可以讓用戶通過手指的移動來移動屏幕上光標的觸敏區(qū)。10II.InputHardware

Anopticalscanneruseslight-sensingequipmenttoconvertimagessuchasapictureortextintoelectronicsignalsthatcanbemanipulatedbyacomputer.Forexample,aphotographcanbescannedintoacomputerandthenincludedinatextdocumentcreatedonthatcomputer.Thetwomostcommonscannertypesaretheflatbedscanner,whichissimilartoanofficephotocopier,andthehand-heldscanner,whichispassedmanuallyacrosstheimagetobeprocessed.光掃描儀利用光感應(yīng)設(shè)備將圖片或文本等形式的圖像轉(zhuǎn)換成計算機能夠處理的電子信號。例如，一張照片能夠被掃入一臺計算機，然后包括在該計算機建立的文本文件中。最常見的兩種掃描儀類型是平板式掃描儀和手持式掃描儀，前者類似一臺辦公復(fù)印機，后者用手動的方式從要處理的圖像上掃過。11II.InputHardwareAmicrophoneisadeviceforconvertingsoundintosignalsthatcanthenbestored,manipulated,andplayedbackbythecomputer.Avoicerecognition

moduleisadevicethatconvertsspokenwordsintoinformationthatthecomputercanrecognizeandprocess.

麥克風是將聲音轉(zhuǎn)換成可被計算機存儲、處理和回放的信號的設(shè)備。語音識別模塊是將說的話轉(zhuǎn)換成計算機能夠識別和處理的信號的設(shè)備。

12II.InputHardwareAmodem,whichstandsformodulator-demodulator,isadevicethatconnectsacomputertoatelephonelineandallowsinformationtobetransmittedtoorreceivedfromanothercomputer.Eachcomputerthatsendsorreceivesinformationmustbeconnectedtoamodem.調(diào)制解調(diào)器代表調(diào)制器―解調(diào)器，是將計算機與電話線連接、允許信息傳給或接自另一臺計算機的設(shè)備。每臺發(fā)送或接收信息的計算機都必需與調(diào)制解調(diào)器相連接。13II.InputHardwareTheinformationsentfromonecomputerisconvertedbythemodemintoanaudiosignal,whichisthentransmittedbytelephonelinestothereceivingmodem,whichconvertsthesignalintoinformationthatthereceivingcomputercanunderstand.計算機發(fā)送的信息由調(diào)制解調(diào)器轉(zhuǎn)換成音頻信號，然后通過電話線傳送到接收調(diào)制解調(diào)器上，由其將信號轉(zhuǎn)換成接收計算機能夠理解的信息。14III.OutputHardwareOutputhardwareconsistsofexternaldevicesthattransferinformationfromthecomputer’sCPUtothecomputeruser.Avideodisplay,orscreen,convertsinformationgeneratedbythecomputerintovisualinformation.Displayscommonlytakeoneoftwoforms:avideoscreenwithacathoderaytube(CRT)oravideoscreenwithaliquidcrystaldisplay(LCD).輸出硬件由將信息從計算機中心處理器傳給計算機用戶的外部設(shè)備構(gòu)成。視頻顯示器或屏幕將計算機生成的信息轉(zhuǎn)換成可視信息。顯示器一般有兩種形式：陰極射線管視頻屏幕和液晶顯示視頻屏幕。15III.OutputHardwareACRT-basedscreen,ormonitor,lookssimilartoatelevisionset.InformationfromtheCPUisdisplayedusingabeamofelectronsthatscansaphosphorescentsurfacethatemitslightandcreatesimages.AnLCD-basedscreendisplaysvisualinformationonaflatterandsmallerscreenthanaCRT-basedvideomonitor.LCDsarefrequentlyusedinlaptopcomputers.基于陰極射線管的屏幕或監(jiān)視器看起來就像一臺電視機。從中心處理器輸出的信息，運用電子束顯示出來，其過程是電子束掃描熒光屏，而熒光屏則發(fā)出光并產(chǎn)生圖像?；谝壕э@示器的屏幕將可視信息顯示在比基于陰極射線管的視頻監(jiān)視器更平、更小的屏幕上。液晶顯示器常常用于膝上型計算機。16III.OutputHardwarePrinterstaketextandimagefromacomputerandprintthemonpaper.Dot-matrixprintersusetinywirestoimpactuponaninkedribbontoformcharacters.Laserprintersemploybeamsoflighttodrawimagesonadrumthatthenpicksupfineblackparticlescalledtoner.Thetonerisfusedtoapagetoproduceanimage.Inkjetprintersfiredropletsofinkontoapagetoformcharactersandpictures.打印機將計算機輸出的文本和圖像打印在紙上。點陣打印機運用細小的金屬絲打擊色帶，從而形成字符。激光打印機運用光束在磁鼓上畫圖像，然后由磁鼓吸起被稱之為色粉的微小黑粒。色粉熔凝到紙上，形成圖像。噴墨打印機將小墨滴噴射到紙上，形成字符和圖像。17IV.StorageHardwareStoragehardwareprovidespermanentstorageofinformationandprogramsforretrievalbythecomputer.Thetwomaintypesofstoragedevicesarediskdrivesandmemory.Thereareseveraltypesofdiskdrives:hard,floppy,magneto-optical,andcompact.Harddiskdrivesstoreinformationinmagneticparticlesembeddedinadisk.Usuallyapermanentpartofthecomputer,harddiskdrivescanstorelargeamountsofinformationandretrievethatinformationveryquickly.

存儲硬件為計算機檢索供應(yīng)信息和程序的永久性存儲。兩種主要的存儲設(shè)備是磁盤驅(qū)動器和存儲器。磁盤驅(qū)動器有幾種類型：硬盤、軟盤、磁光盤和光盤。硬盤驅(qū)動器將信息存儲在盤中嵌入的磁性顆粒中。硬盤驅(qū)動器通常是計算機的固定部分，能存儲大量的信息并對其進行快速的檢索。18IV.StorageHardwareFloppydiskdrivesalsostoreinformationinmagneticparticlesembeddedinremovabledisksthatmaybefloppyorrigid.Floppydisksstorelessinformationthanaharddiskdriveandretrievetheinformationatamuchslowerrate.Magneto-opticaldiscdrivesstoreinformationonremovablediscsthataresensitivetobothlaserlightandmagneticfields.Theycantypicallystoreasmuchinformationasharddisksbuthaveslightlyslowerretrievalspeeds.軟盤驅(qū)動器也將信息存儲在磁性顆粒中，但這些顆粒是嵌入在可移動的盤中，而這些盤既可能是軟的也可能是硬的。軟盤比硬盤存儲的信息少，檢索該信息的速度也慢得多。磁光盤驅(qū)動器將信息存儲在對激光和磁場都敏感的可移動盤上。它們可存儲的信息通常與硬盤一樣多，但檢索速度略微慢一點。19IV.StorageHardware

Compactdiscdrives(CD-ROM)storeinformationonpitsburnedintothesurfaceofadiscofreflectivematerial.TheinformationstoredonCD-ROMscannotbeerased(erase)oroverwritten(overwrite)withnewinformation.Theycanstoreaboutasmuchinformationasaharddrivebuthaveaslowerrateofinformationretrieval.由反射材料制成的光盤，其表面燒蝕出凹陷區(qū)。光驅(qū)（CD-ROM）就是將信息存儲于此。存儲在光盤上的信息不能擦除或用新信息改寫。它們能夠存儲和硬盤差不多的信息量，但信息檢索速度比其慢。

20IV.StorageHardwareMemoryreferstothecomputerchipsthatstoreinformationforquickretrievalbytheCPU.Randomaccessmemory(RAM)isusedtostoretheinformationandinstructionsthatoperatethecomputer’sprograms.存儲器是指存儲信息供中心處理器快速檢索的計算機芯片。隨機訪問存儲器（RAM）用來存儲操作計算機程序的信息和指令。21IV.StorageHardware

Typically,programsaretransferredfromstorageonadiskdrivetoRAM.RAMisalsoknownasvolatilememorybecausetheinformationwithinthecomputerchipsislostwhenpowertothecomputeristurnedoff.通常，程序由磁盤驅(qū)動器的存儲區(qū)調(diào)到隨機訪問存儲器中。隨機訪問存儲器也稱作易失性存儲器，因為當計算機的電源關(guān)閉時，計算機芯片中的信息隨著丟失。22IV.StorageHardwareRead-onlymemory(ROM)containscriticalinformationandsoftwarethatmustbepermanentlyavailableforcomputeroperation,suchastheoperatingsystemthatdirectsthecomputer’sactionsfromstartuptoshutdown.ROMiscallednonvolatilememorybecausethememorychipsdonotlosetheirinformationwhenpowertothecomputeristurnedoff.只讀存儲器（ROM）包含必需永久可供計算機操作運用的關(guān)鍵信息和軟件，如從開機到關(guān)機始終指揮計算機的運行的操作系統(tǒng)。只讀存儲器稱之為非易失性存儲器，因為當計算機的電源關(guān)閉時，存儲芯片中的信息不會丟失。23IV.StorageHardwareSomedevicesservemorethanonepurpose.Forexample,floppydisksmayalsobeusedasinputdevicesiftheycontaininformationtobeusedandprocessedbythecomputeruser.Inaddition,theycanbeusedasoutputdevicesiftheuserwantstostoretheresultsofcomputationsonthem.有些設(shè)備有不止一種用途。例如，軟盤也可用作輸入設(shè)備，假如它們含有計算機用戶要運用和處理的信息的話。此外，它們也可用作輸出設(shè)備，假如用戶想將計算結(jié)果存儲在它們上面的話。24V.HardwareConnectionsTofunction,hardwarerequiresphysicalconnectionsthatallowcomponentstocommunicateandinteract.Abusprovidesacommoninterconnectedsystemcomposedofagroupofwiresorcircuitrythatcoordinates(coordinate)andmovesinformationbetweentheinternalpartsofacomputer.要想運轉(zhuǎn)，硬件須要物理連接，使元件之間能夠溝通和相互作用?？偩€供應(yīng)了一種常見的互連系統(tǒng)，它由一組導(dǎo)線或電路組成，在計算機的內(nèi)部組成部分之間協(xié)調(diào)和移動信息。25V.HardwareConnectionsAcomputerbusconsistsoftwochannels(channel):onethattheCPUusestolocatedata,calledtheaddressbus,andanothertosendthedatatothataddress,calledthedatabus.Abusischaracterized(characterize)bytwofeatures(feature):howmuchinformationitcanmanipulateatonetime,calledthebuswidth,andhowquicklyitcantransferthesedata.計算機總線由兩條通道組成：一條由中心處理器用來給數(shù)據(jù)定位，叫做地址總線；另一條用來將該數(shù)據(jù)送往那個地址，叫做數(shù)據(jù)總線?？偩€可用兩個特征來描述：一次可處理的信息量，稱為總線寬度，和傳送這些數(shù)據(jù)的速度。26V.HardwareConnectionsAserialconnectionisawireorsetofwiresusedtotransferinformationfromtheCPUtoanexternaldevicesuchasamouse,keyboard,modem,scanner,andsometypesofprinters.Thistypeofconnectiontransfersonlyonepieceofdataatatime,andisthereforeslow.Theadvantagetousingaserialconnectionisthatitprovideseffectiveconnectionsoverlongdistances.串行連接是一根或一組導(dǎo)線，用于將信息從中心處理器傳送到外部設(shè)備，如鼠標、鍵盤、調(diào)制解調(diào)器、掃描儀和一些類型的打印機。這種連接一次只能傳送一段數(shù)據(jù)，因此很慢。運用串行連接的好處在于它能供應(yīng)遠距離的有效連接。27V.HardwareConnectionsAparallelconnectionusesmultiplesetsofwirestotransferblocks(block)ofinformationsimultaneously.Mostscannersandprintersusethistypeofconnection.Aparallelconnectionismuchfasterthanaserialconnection,butitislimitedtodistancesoflessthan3m(10ft)betweentheCPUandtheexternaldevice.并行連接運用多組導(dǎo)線來同時傳送數(shù)個信息塊。大多數(shù)掃描儀和打印機運用這種連接方式。并行連接比串行連接快得多，但是它在中心處理器和外部設(shè)備之間的傳輸距離僅限于不到3米（10英尺）。28ExerciseIII.

CD-ROMstandsforcompactdiskread-onlymemory.Unlikefloppyandharddisks,whichusemagneticchargestorepresent1sand0s,opticaldisksusereflectedlight.OnaCD-ROMdisk,1sand0sarerepresentedbyflatarea