計算機專業(yè)英語 第3版 課件 朱龍 Chapter6 Computer Network Technology（計算機網(wǎng)絡(luò)技術(shù)）

閱讀材料ReadingMaterial計算機專業(yè)英語chaptersix

ComputerNetworkTechnologyMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1.VarietiesofEthernet計算機專業(yè)英語FastEthernet100BASE-T:Atermforanyofthethreestandardsfor100

Mbit/sEthernetovertwistedpaircables,Including100BASE-TX,100BASE-T4and100BASE-T2.Asof2009,100BASE-TXhastotallydominatedthemarket,andisoftenconsideredtobesynonymouswith100BASE-Tininformalusage.100BASE-TX:100

Mbit/sEthernetoverCategory5cables(usingtwooutoffourpairs).Similarstar-shapedconfigurationto10BASE-T.100BASE-T4:100

Mbit/sEthernetoverCategory3cables(asusedfor10BASE-Tinstallations).Usesallfourpairsinthecable,andislimitedtohalf-duplex.Nowobsolete,asCategory5cablesarethenorm.100BASE-T2:100

Mbit/sEthernetoverCategory3cables.Usingonlytwopairs,andsupportingfull-duplex,itisfunctionallyequivalentto100BASE-TX,butsupportsoldcable.Noproductssupportingthisstandardwasevermanufactured.100BASE-FX:100

Mbit/sEthernetoverfiber.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1.VarietiesofEthernet計算機專業(yè)英語GigabitEthernet1000BASE-T:1

Gbit/soverunshieldedtwistedpaircoppercabling(atleastCategory5cables,withCategory5estronglyrecommended).1000BASE-SX:1

Gbit/sovershortrangemulti-modefiber.1000BASE-LX:1

Gbit/soverlongrangesingle-modefiber.1000BASE-CX:Ashort-haulsolution(upto25

m)forrunning1

Gbit/sEthernetoverspecialcoppercable.Predates1000BASE-T,andnowobsolete.

10-gigabitEthernetThe10gigabitEthernetfamilyofstandardsencompassesmediatypesforsingle-modefibre(longhaul),multi-modefibre(upto300

m),copperbackplane(upto1

m)andcoppertwistedpair(upto100

m).ItwasfirststandardisedasIEEEStd802.3ae-2002,butisnowincludedinIEEEStd802.3-2008.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1.VarietiesofEthernet計算機專業(yè)英語10GBASE-SR:designedtosupportshortdistancesoverdeployedmulti-modefibercabling,ithasarangeofbetween26

mand82

mdependingoncabletype.Italsosupports300

moperationoveranew2000

MHz·kmmulti-modefiber.10GBASE-LX4:useswavelengthdivisionmultiplexingtosupportrangesofbetween240

mand300

moverdeployedmulti-modecabling.Alsosupports10

kmoversingle-modefiber.10GBASE-LRand10GBASE-ER:thesestandardssupport10

kmand40

kmrespectivelyoversingle-modefiber.10GBASE-SW,10GBASE-LWand10GBASE-EW.ThesevarietiesusetheWANPHY,designedtointeroperatewithOC-192/STM-64SONET/SDHequipment.Theycorrespondatthephysicallayerto10GBASE-SR,10GBASE-LRand10GBASE-ERrespectively,MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1.VarietiesofEthernet計算機專業(yè)英語andhenceusethesametypesoffiberandsupportthesamedistances.(ThereisnoWANPHYstandardcorrespondingto10GBASE-LX4.)10GBASE-T:designedtosupportcoppertwistedpairandwasspecifiedbytheIEEEStd802.3an-2006whichhasbeenincorporatedintotheIEEEStd802.3-2008.MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?2.ARPANET計算機專業(yè)英語TheARPANET(AdvancedResearchProjectsAgencyNetwork),createdbytheARPAoftheUnitedStatesDepartmentofDefenseduringtheColdWar,wastheworld’sfirstoperationalpacketswitchingnetwork,andthepredecessoroftheglobalInternet.Packetswitching,nowthedominantbasisforbothdataandvoicecommunicationworldwide,wasanewandimportantconceptindatacommunication.Previously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?2.ARPANET計算機專業(yè)英語Withpacketswitching,asystemcoulduseonecommunicationlinktocommunicatewithmorethanonemachinebydisassemblingdataintodatagrams,thengathertheseaspackets.Notonlycouldthelinkbeshared(muchasasinglepostboxcanbeusedtopostletterstodifferentdestinations),buteachpacketcouldberoutedindependentlyofotherpackets.AformofpacketswitchingdesignedbyLincolnLaboratoryscientistLawrenceRobertsunderlaythedesignofARPANET.BackgroundofARPANETTheearliestideasofacomputernetworkintendedtoallowgeneralcommunicationbetweenusersofvariouscomputerswereformulatedbyJ.C.R.LickliderofBolt,BeranekandNewman(BBN)inAugust1962,inaseriesofmemosdiscussinghis“IntergalacticComputerNetwork”concept.TheseideascontainedalmosteverythingthattheInternetistoday.MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?2.ARPANET計算機專業(yè)英語InOctober1963,LickliderwasappointedheadoftheBehavioralSciencesandCommandandControlprogramsatARPA(asitwasthencalled),theUnitedStatesDepartmentofDefenseAdvancedResearchProjectsAgency.HethenconvincedIvanSutherlandandBobTaylorthatthiswasaveryimportantconcept,althoughheleftARPANETbeforeanyactualworkonhisvisionwasperformed.ARPAandTaylorcontinuedtobeinterestedincreatingacomputercommunicationnetwork,inparttoallowARPA-sponsoredresearchersinvariouslocationstousevariouscomputerswhichARPAwasproviding,andinparttomakenewsoftwareandotherresultswidelyavailablequickly.Taylorhadthreedifferentterminalsinhisoffice,connectedtothreedifferentcomputerswhichARPAwasfunding:onefortheSDCQ-32inSantaMonica,oneforProjectGenieattheUniversityofCalifornia,Berkeley,andoneforMulticsatMIT.Taylorlaterrecalled:MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?2.ARPANET計算機專業(yè)英語“Foreachofthesethreeterminals,Ihadthreedifferentsetsofusercommands.SoifIwastalkingonlinewithsomeoneatS.D.C.andIwantedtotalktosomeoneIknewatBerkeleyorM.I.T.aboutthis,IhadtogetupfromtheS.D.C.terminal,gooverandlogintotheotherterminalandgetintouchwiththem.Isaid,oh,man,it’sobviouswhattodo:Ifyouhavethesethreeterminals,thereoughttobeoneterminalthatgoesanywhereyouwanttogo.ThatideaistheARPANET.”Somewhatcontemporaneously,anumberofpeoplehad(mostlyindependently)workedoutvariousaspectsofwhatlaterbecameknownas“packetswitching”,withthefirstpublicdemonstrationbeingmadebytheUK’sNationalPhysicalLaboratory(NPL)on5August5,1968.ThepeoplewhocreatedtheARPANETwouldeventuallydrawonallthesedifferentsources.MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?3.Hotmail計算機專業(yè)英語InDecember1995,SabeerBhatiaandJackSmithvisitedtheInternetventurecapitalistDraperFisherJurvetsonandproposeddevelopingafreeWeb-basedE-mailsystem.TheideawastogiveafreeE-mailaccounttoanyonewhowantedone,andtomaketheaccountsaccessiblefromtheWeb.WithWeb-basedE-mail,anyonewithaccesstotheWeb——say,fromaschoolorcommunitylibrary——couldreadandsendE-mails.Furthermore,web-basedE-mailwouldoffergreatmobilitytoitssubscribers.Inexchangefor15percentofthecompany,DraperFisherJurvetsonfinancedBhatiaandSmith,whoformedacompanycalledHotmail.Withthreefull-timepeopleand12～14part-timepeoplewhoworkedforstockoptions,theywereabletodevelopandlaunchtheserviceinJuly1996.Withinamonthafterlaunchtheyhad100

000subscribers.Thenumberofsubscriberscontinuedtogrowrapidly,withalloftheirsubscribersbeingexposedtoadvertisingbannerswhilereadingtheirE-mail.MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?3.Hotmail計算機專業(yè)英語withalloftheirsubscribersbeingexposedtoadvertisingbannerswhilereadingtheirE-mail.InDecember1997,lessthan18monthsafterlaunchingtheservice,Hotmailhadover12millionsubscribersandwasacquiredbyMicrosoft,reportedlyfor$400milliondollars.

ThesuccessofHotmailisoftenattributedtoits“first-moveradvantage”andtotheinherent“viralmarketing”ofE-mail.Hotmailhadafirst-moveradvantagebecauseitwasthefirstcompanytoofferWeb-basedE-mail.Othercompanies,ofcourse,copiedHotmail’sidea,butHotmailhadasix-monthleadonthem.Thecovetedfirst-moveradvantageisobtainedbyhavinganoriginalidea,andthendevelopingquicklyandsecretly.Aserviceoraproductissaidtohaveviralmarketingifitmarketsitself.MissLi:AsalesgirlinComputerTownPreviously,datacommunicationwasbasedontheideaofcircuitswitching,asintheoldtypicaltelephonecircuit,whereadedicatedcircuitistiedupforthedurationofthecallandcommunicationisonlypossiblewiththesinglepartyontheotherendofthecircuit.Mr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?3.Hotmail計算機專業(yè)英語E-mailisaclassicexampleofaservicewithviralmarketing—thesendersendsamessagetooneormorerecipients,andthenalltherecipientsbecomeawareoftheservice.Hotmaildemonstratedthatthecombinationoffirst-moveradvantageandviralmarketingcanproduceakillerapplication.Perhapssomeofthestudentsreadingthisbookwillbeamongthenewentrepreneurswhoconceiveanddevelopfirst-moverInternetserviceswithinherentviralmarketing.感謝觀看Ｔｈhankyouforwatching計算機專業(yè)英語練習(xí)Exercises計算機專業(yè)英語chaptersixComputerNetworkTechnologyMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1．MatchtheexplanationsinColumnBwithwordsandexpressionsinColumnA.計算機專業(yè)英語搭配下列每組中意義相同的詞或短語AB交換機IP路由器IDPS組件Switch傳輸控制協(xié)議Router互聯(lián)網(wǎng)協(xié)議Component萬維網(wǎng)TCP入侵檢測和防御系統(tǒng)WWWAB超文本傳輸控制協(xié)議NetworkSafety電子郵件Firewall文件傳輸協(xié)議E-mail防火墻IDS入侵檢測系統(tǒng)FTP網(wǎng)絡(luò)安全OSI開放系統(tǒng)互聯(lián)HTTPMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?2.Choosetheproperwordstofillintheblanks.計算機專業(yè)英語選詞填空ALANisusedforcommunicationsinasmallcommunityinwhichresources,suchas(),software,andservers,areshared.EachdeviceconnectedtoaLANhasaunique().TwoormoreLANsofthesametypecanalsobeconnectedto()dataframesamongmultipleusersofotherlocalareanetworks.InLANs,()areadditionalheadersappendedforlocalrouting.Thesenew-lookingpacketsareknownas().Packets，address，frames，printers，forwardWordstobechosenfrom:（可選詞）MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?3．TranslatethefollowingEnglishSentencesintoChinese.計算機專業(yè)英語將下面英語句子翻譯為中文（1）TheInternetisaglobalsystemofinterconnectedcomputernetworksthatusethestandardInternetProtocolSuite(TCP/IP)toservebillionsofusersworldwide.___________________________________________________（2）Aswithmostapplication-layerprotocols,SMTPhastwosides:Aclientside,whichexecutesonthesender’smailserver,andaserverside,whichexecutesontherecipient’smailserver.

__________________________________________________（3）Inthestartopology,allusersaredirectlyconnectedtoacentraluserthroughtwounidirectionallinks:oneforuplinkandtheotherfordownlink.

__________________________________________________（4）Acomputernetworkisagroupofcomputersthatareconnectedtoeachotherforthepurposeofcommunication.__________________________________________________MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?3．TranslatethefollowingEnglishSentencesintoChinese.計算機專業(yè)英語將下面英語句子翻譯為中文

（5）WANsareusedtoconnectLANsandothertypesofnetworkstogether,sothatusersandcomputersinonelocationcancommunicatewithusersandcomputersinotherlocations.__________________________________________________

Let’sgo!感謝觀看Ｔｈhankyouforwatching計算機專業(yè)英語情境對話SituationDialogue計算機專業(yè)英語chaptersix

ComputerNetworkTechnologyMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?Shoppingonline計算機專業(yè)英語網(wǎng)購XiaoMingandLiLiangaregoodfriends.LiLiangisacomputerexpertwhooftenbuysthingsonline.XiaoMing:Moreandmorepeoplelikeon-lineshopping.LiLiang:Yes,thepriceisloweronline.XiaoMing:Isawadigitalcameraonline.LiLiang:Areyoureadytodoshoppingonline?XiaoMing:Yes,butIdonotknowhowtodoit,canyoushowme?小明和李亮是好朋友。李亮是計算機高手，經(jīng)常在網(wǎng)上買東西。小明：現(xiàn)在喜歡網(wǎng)上購物的人越來越多了。李亮：是呀，網(wǎng)上的東西價格比較便宜。小明：我也在網(wǎng)上看中一款數(shù)碼相機。李亮：你也準備網(wǎng)上購物？小明：是的，但是我不知道怎么做，你能教教我嗎？MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?Shoppingonline計算機專業(yè)英語網(wǎng)購LiLiang:OK.Therearemanyfishingsitesonthenetwork,sofirstly，selectingthesitewhichyoucantrustisveryimportant.XiaoMing:Whatsites?LiLiang:Tobuyadigitalcamera,thereareJingdong,Newegg,Taobao,eBay,andsoon.XiaoMing:Canitbetradedafterchoosingtherightproducts?李亮：好的。網(wǎng)絡(luò)上有很多釣魚網(wǎng)站，選擇可以信任的網(wǎng)站是非常重要的。

小明：有哪些網(wǎng)站呢？李亮：買數(shù)碼相機的話，有京東、新蛋、淘寶、易趣等。小明：選好產(chǎn)品后就可以進行交易了？MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?Shoppingonline計算機專業(yè)英語網(wǎng)購LiLiang:Yes,selectadigitalcamera,pay,receivedigitalcamera.It’ssosimple.XiaoMing:Nowondereveryonelikesonlineshopping.LiLiang:Althoughsimple,manytechniquesareused.Takethenetworkside,thereareHTTP,DNS,networkdeviceconfiguration,thedevelopmentofstandardsandprotocols,andsoon.李亮：是的，選數(shù)碼相機、付錢，收到數(shù)碼相機，就是這么簡單。小明：難怪大家都喜歡網(wǎng)上購物。李亮：雖然簡單，但用到的技術(shù)很多。就拿網(wǎng)絡(luò)方面來說，主要有HTTP、DNS、網(wǎng)絡(luò)設(shè)備配置、標準和協(xié)議的制定等。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?Shoppingonline計算機專業(yè)英語網(wǎng)購XiaoMing:Itsoundsverycomplicated.LiLiang:Ofcourse,onlinechattingandwatchingmoviesareusedmanynetworkingtechnologies.XiaoMing:NowIturnthecomputeron,HowdoyouthinkthedigitalcameraIchosed?LiLiang:OK.小明：聽起來很復(fù)雜。李亮：當(dāng)然，網(wǎng)上聊天、看電影，這些都用到很多的網(wǎng)絡(luò)技術(shù)。小明：我把計算機打開，你看我選的數(shù)碼相機怎么樣？李亮：好的。感謝觀看Ｔｈhankyouforwatching計算機專業(yè)英語對照閱讀ReadingandComparing計算機專業(yè)英語chaptersix

ComputerNetworkTechnologyMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatareComputerViruses?計算機專業(yè)英語什么是計算機病毒？Computervirusesareprogramswrittenby“mean”people.Thesevirusprogramsareplacedintoacommonlyusedprogramsothatprogramwillruntheattachedvirusprogramasitboots,therefore,itissaidthatthevirus“infects”theexecutablefileorprogram.計算機病毒是“有不良企圖”的人撰寫的程序。這些病毒程序被放置在一個常用的程序中，該程序啟動后就會運行附加病毒程序，因此，我們說該病毒“感染”了可執(zhí)行文件或程序。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatareComputerViruses?計算機專業(yè)英語什么是計算機病毒？ExecutablefilesincludeMacintosh“systemfiles”(suchassystemextensions,INITsandcontrolpanels)andapplicationprograms(suchaswordprocessingprogramsandspreadsheetprograms).VirusesworkthesamewaysinWindowsorDOSmachinesbyinfectingziporexefiles.可執(zhí)行文件包括Macintosh“系統(tǒng)文件”（如系統(tǒng)擴展、初始化和控制面板）和應(yīng)用程序（如文字處理程序和電子表格程序）。病毒在Windows或DOS機器上感染zip或exe文件也采用相同的工作方式。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatareComputerViruses?計算機專業(yè)英語什么是計算機病毒？Avirusisinactiveuntilyouexecuteaninfectedprogramorapplicationorstartyourcomputerfromadiskthathasinfectedsystemfiles.Onceavirusisactive,itloadsintoyourcomputer’smemoryandmaysaveitselftoyourharddriveorcopiesitselftoapplicationsorsystemfilesondisksyouuse.病毒處于非活動狀態(tài)，直到你執(zhí)行受感染的應(yīng)用程序或從磁盤啟動已經(jīng)感染的計算機系統(tǒng)文件才被激活。病毒一旦激活，它將加載到你的計算機內(nèi)存中，并可能保存到你的硬盤驅(qū)動器或?qū)⒆陨韽?fù)制到磁盤上的應(yīng)用程序或系統(tǒng)文件中。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatareComputerViruses?計算機專業(yè)英語什么是計算機病毒？Somevirusesareprogrammedspecificallytodamagethedataonyourcomputerbycorruptingprograms,deletingfiles,orevenerasingyourentireharddrive.Manyvirusesdonothingmorethandisplayamessageormakesounds/verbalcommentsatacertaintimeoraprogrammingeventafterreplicatingthemselvestobepickedupbyotherusersonewayoranother.一些病毒是為了損害你的計算機上的數(shù)據(jù)專門設(shè)計的程序，它們破壞程序、刪除文件，甚至清除你的整個硬盤驅(qū)動器。許多病毒只是顯示一條消息，或使聲音/口頭禪注釋自我復(fù)制至其他用戶，自我復(fù)制是在某一特定的時間或者程序事件后執(zhí)行的。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatareComputerViruses?計算機專業(yè)英語什么是計算機病毒？Othervirusesmakeyourcomputer’ssystembehaveerraticallyorcrashfrequently.Sadlymanypeoplewhohaveproblemsorfrequentcrashesusingtheircomputersdonotrealizethattheyhaveavirusandlivewiththeinconveniences.其他病毒使計算機系統(tǒng)的行為不正?；蝾l繁崩潰，可悲的是很多使用有問題計算機的用戶沒有意識到，是病毒給他們帶來了不便。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatVirusesDon’tDo!計算機專業(yè)英語什么是病毒做不了的！Computervirusescannotinfectwriteprotecteddisksorinfectwrittendocuments.Virusesdonotinfectcompressedfiles,unlessthefilewasinfectedpriortothecompression.Compressedfilesareprogramsorfileswithitscommoncharacters,etc.removedtotakeuplessspaceonadisk.Virusesdonotinfectcomputerhardware,suchasmonitorsorcomputerchips;theyonlyinfectsoftware.計算機病毒無法感染寫保護的磁盤或書面文件。病毒不能感染壓縮的文件，除非文件是在被壓縮之前感染了。壓縮文件程序具有的共同特征是文件占用的磁盤空間較少。病毒不感染計算機硬件，如顯示器或計算機芯片，它們只感染軟件。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatVirusesDon’tDo!計算機專業(yè)英語什么是病毒做不了的！Inaddition,MacintoshvirusesdonotinfectDOS/Windowcomputersoftwareandviceversa.Forexample,theMelissavirusincidentoflate1998andtheILOVEYOUvirusof2000workedonlyonWindowbasedmachinesandcouldnotoperateonMacintoshcomputers.此外，Macintosh病毒不感染DOS/窗口計算機軟件，反之亦然。例如，1998年底的Melissa病毒和2000年的ILOVEYOU病毒只能在基于窗口工作的機器上運行，不能在Macintosh計算機上運行。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?WhatVirusesDon’tDo!計算機專業(yè)英語什么是病毒做不了的！Onefurthernoteisvirusesdonotnecessarilyletyouknowtheyarepresentinyourmachine,evenafterbeingdestructive.Ifyourcomputerisnotoperatingproperly,itisagoodpracticetocheckforviruseswithacurrent“viruschecking”program.還有一項值得注意的是，病毒并不一定讓你知道它們目前是在你的機器上，雖然它們之后會有破壞性。如果你的計算機沒有正常運行，用流行的查毒軟件檢查病毒是一個很好的做法。MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?HowdoVirusesSpread?計算機專業(yè)英語病毒如何傳播？Virusesbegintoworkandspreadwhenyoustartuptheprogramorapplicationinwhichthevirusispresent.Forexample,awordprocessingprogramthatcontainsaviruswillplacethevirusinmemoryeverytimethewordprocessingprogramisrun.當(dāng)你啟動存在病毒的應(yīng)用或程序時，病毒開始運行并傳播。例如，包含一個病毒文字處理程序?qū)言摬《痉胖迷趦?nèi)存中，隨著每次文字處理程序的運行而傳播病毒。MissLi: