《计算机专业英语》课件第26章

GigabitEthernet

GigabitEthernetcouldn’thappenatabettertime.Buildingontheproliferationofswitched10Mand100Mbit/secEthernetdevices,1Gbit/secEthernetisanelegantandtimelynextstep.

ButGigabitEthernetisnotasimplescalingupoftheEthernetwealreadyknow.1Althoughitshouldreadilyfitintoexistingnetworksandbeeasylouseandmanage,thissuperchargedEthernettechnologyentailsmorerobustproductengineering.

2Here’salookatthetypesofGigabitEthernetproductsthatwillappearinthemarket

bymid1997andwhatusersshouldlookforinevaluatingtheseproducts.

Fivetypesofhardwarewillappeartoservethegigabitmigration:GigabitEthernetnetworkinterfacecards(NIC),aggregatingswitchesthatconnect100Mand1Gbit/Ethernetsegments,all-gigabitEthernetswitches,all-gigabitEthernetrepeatersandgigabitenabledrouters.

Inconsideringgigabit-persecondupgradesforserversandpowerworkstations,usersmustselectGigabitEthernetNICscarefully.3At1Gbit/sec,CPUscannotkeepupwithnetworkthroughputunlesstheNICprovidesintelligent,hostassistfunctions.ThisalsowillapplytoGigabitEthernetinterfacesonroutersandmayexistinglowercapacityswitches.

Traditionally,aworkstation’sthroughputdependsonitsbusandmemoryarchitecture,aswellasitsCPUspeed.4Withthe32bitPCIbus,computershavethecapacitytobursttrafficat1Gbit/sec.The64bitPCIbushashigherthroughput(2Gbit/sec).

Thisfasterbusspeedisamajorfactoringigabitreadiness.But,atsuchspeed,thesystemCPUcaneasilyconsume10applicationsandthenet,leavingnoprocessingpowerforapplicationsorotheroperatingsystemtasks.

5GigabitEthernetrequiresthird-generationadaptersfeaturingonboardReducedInstructionSetComputingprocessorsthatperformintelligent,host-specificoff-loadfunctions.Incomingdataismoveddirectlyfromthenettohostmemorylocationsthatareimmediatelyalignedforaccessbytheapplications.Thiseliminatesthemultipleinterruptsofpacketcopying.

Infact,theseNICscanissueasingleCPUinterruptformultipledatapackets-radicallyalteringthepacket/interruptratio,therebyeliminatingthescalabilityproblemsinherentinolderNICdesigns.Thisnotonlyenablesfasterthroughput,butalsohelpsapplicationsrunmoreefficientlybyfreeingthehostCPUforapplicationprocessing.

Inaddition,thepacket/interruptratiocanbeuser-configuredorautosensedonsuchNICs.6Thisallowsfor“adaptive”interruptsthatvaryinfrequencydependingonthenet’sburstvolume.7IntelligentGigabitEthernetadapterswillevaluatenetactivitytodeterminewhichmethodtouseatwhichtime.NewWords

proliferationn.增殖elegantadj.优美的timelyadj.及时的scalingn.图像缩放superchargev.增加负荷entailv.承担robustadj.坚固的evaluatev.估价aggregatev.聚集segmentn.图段repeatern.转发器routern.路由器upgradev.使升级workstationn.工作站burstn.脉冲,突发consumev.消耗orchestratev.编管弦乐曲featurev.起重要作用alignv.排列eliminatev.消除interruptv.中断issuen.问题alterv.转变therebyadv.因此scalabilityn.可伸缩性inherentadj.固有的efficientlyadv.有效地configurev.配置adaptiveadj.适应的PhrasesandExpressions

GigabitEthernet千兆位以太网fitinto符合keepupwith跟上applyto适合,适应aswellas还有,和,并且TheExplanationofDifficultStatements

1.Althoughitshouldreadilyfitintoexistingnetworksandbeeasylouseandmanage,thissuperchargedEthernettechnologyentailsmuchmorerobustproductengineering.

分析:此句为although引导的让步状语从句,译为“虽然……但是……”。

句意:虽然它应该很容易地适应已有的网络,容易使用和管理,但这个优越的以太网技术需要很多更扎实的产品工程设计。

2.Here’salookatthetypesofGigabitEthernetproductsthatwillappearinthemarketbymid1997andwhatusersshouldlookforinevaluatingtheseproducts.

分析:此句中的“and”连接两个并列宾语。“whatusersshouldlookforinevaluatingtheseproducts”为名词性从句作宾语。

句意:这里让我们来看一看到1997年市场上将出现的千兆位以太网产品的类型以及用户应选择哪类产品进行评估。

3.At1Gbit/sec,CPUscannotkeepupwithnetworkthroughputunlesstheNICprovidesintelligent,hostassistfunctions.

分析:此句中“unlesstheNICprovidesintelligent,hostassistfunctions”为条件状语从句,译为“除非”或“如果……不……”。句意:在1千兆位/秒的速度上,除非网卡提供了智能的、受主机辅助的功能,否则CPU就跟不上网络的吞吐量。

4.Withthe32bitPCIbus,computershavethecapacitytobursttrafficat1Gbit/sec.

分析:“Withthe32bitPCIbus”句型为“with+名词/名词短语”用作状语,说明方式、条件、伴随情况等。例如:TomdidhishomeworkwiththeTVon.

句意:有了32位PCI总线,计算机就拥有将信息流量提升到1千兆位/秒的能力。

5.GigabitEthernetrequiresthird-generationadoptersfeaturingonboardReducedInstructionSetComputing(RISC)processorsthatperformintelligent,host-specificoff-loadfunctions.

分析:此句中“featuringonboardReducedInstructionSetComputing(RISC)processorsthatperformintelligent,host-specificoff-loadfunctions”为现在分词作定语,其中又包含that所引导的定语从句。

句意:千兆位以太网需要第三代适配器,具有板上装有完成智能的专为主机卸载功能的精简指令集(RISC)处理器。

6.Thisallowsfor“adaptive”interruptsthatvaryinfrequencydependingonthenet’sburst

volume.

分析:“dependingonthenet’sburstvolume”为现在分词作状语,“dependon”意为“依靠、依据”。

句意:这就允许依据网上脉冲数量多少而不断改变频率的“自适应”中断。

7.IntelligentGigabitEthernetadapterswillevaluatenetactivitytodeterminewhichmethodtouseatwhichtime.

分析:“whichmethodtouse”结构为“特殊疑问词+动词不定式”。例如:Idon’tknowwhattodoandhowtodo.

句意:智能千兆位以太网适配器将评估网上活动,以确定在何时利用何种方法。GrammarTranslationskills专业缩略词的翻译

在英文的科技书刊中,很多术语往往以缩略词的形式出现。但过多的科技缩语的出现,不免会让读者感到困惑,往往要花费大量时间去寻找其出处,因此在专业缩略词翻译成中文时应作适当处理,以便于阅读。

1)对于通行的科技缩略语可直接照抄于译文中。有些常用缩略语已为人们普遍接受和了解,不加注解也不致造成误解,这时在翻译时可直接抄录。例如:

InmostcommercialAMbroadcastreceiversofthesuperheterodynetype,theintermediatefrequencyis465kHz.多极民用ＡＭ波超外差接收机中频是465kHz.

ThedatestructureusedinanSNAnetworkisSDIC.

SNA网络中所用的数据结构是ＳＤＬＣ。

2)直接译出原文中的缩略词,有些缩略词中文译文并不长或作者为使原文简练而自行采用的略语,并无普遍意义。这时最好直接采用中文译出。例如:

FollowingtheIFisadetector

中频线路之后接有一个检波器。ＣＣＣisalsocontainedinthesystembasebandequipment

呼叫连接群集器也包括在系统基带设备中。

3)引用缩略语加适当注释当缩略语译文语意太长,而引用缩略语确实能使译文简练时可在缩略词第一次出现时加以适当注释。注解办法可以采用“正文头注”,或采用“脚注”等办法。例如:ＨＮＳ’PESnetworkisahighlyadvancedVSATtransmissionsystemthatiscapableofsupportinginteractive,batch,andLANtrafficbetweenremoteuserequipmentandhostfacilities,orbetweenanytworemotes.译法１:ＨNS’PES(HughesNetworkSystem,Jnc,PersonalEarthStation)网是一个高度先进的ＶＳＡＴ(VerySmallApertureTerminal)传输系统,它可以在远端用户设备和主站设备之间或任何两个远端用户之间支持交互型业务、批量数据传输业务和ＬＡＮ业务。译法２:ＨＮＳ’PES(体斯公司个人地球站)网是一个高度先进的ＶＳＡＴ(微口径终端)传输系统,它可以在远端用户设备和主站设备之间或任何两个远端用户之间支持交互型业务、批量数据传输业务和局域网业务。译法３:体斯公司个人地球站(ＨＮＳ’PES)网是一个高度先进的微口径终端(ＶＳＡＴ)传输系统,它可以在远端用户设备和主站设备之间或任何两个远端用户之间支持交互型业务、批量数据业务和局域网(ＬＡＮ)业务。ExerciseⅠ.Fillintheblanksaccordingtothetext:(1)Buildingontheproliferationofswitched______________bit/secEthernetdevices,1Gbit/secEthernetisanelegantandtimelynextstep.(2)Fivetypesofhardwarewillappeartoservethegigabitmigration:GigabitEthernetnetworkinterfacecards(NIC),aggregatingswitchesthatconnect100Mand1Gbit/Ethernetsegments,all-gigabitEthernetswitches,______________.(3)At______________,CPUscannotkeepupwithnetworkthroughputunlesstheNICprovidesintelligent,hostassistfunctions.(4)Traditionally,a______________dependsonitsbusandmemoryarchitecture,aswellasitsCPUspeed.(5)GigabitEthernetrequiresthirdgenerationadaptersfeaturingonboardReducedInstructionSetComputingprocessorsthat______________.Ⅱ.Decidewhethereachofthefollowingstatementsistrueorfalseaccordingtothetext:(1)GigabitEthernetisasimplescalingupoftheEthernetwealreadyknow.(2)The64bitPCIbushashigherthroughput(2Gbit/sec).Thisfasterbusspeedisamajorfactoringigabitreadiness.(3)Gigabitenabledroutersisn’tonetypeofhardwarewillappeartoservethegigabitmigration.(4)Inconsideringgigabit-persecondupgradesforserversandpowerworkstations,usersmustselectGigabitEthernetNICscarefully.(5)IntelligentGigabitEthernetadapterswillevaluatenetactivitytodeterminewhichmethodtouseatwhichtime.Ⅲ.TranslatethefollowingsentencesintoChinese:(1)Applicationsusekernelfunctionsthroughapplicationprogramminginterfaces(API),whichareasetofstandardroutinesusedbyprograms.(2)Thesewereimportanttricksneededtoincreasethespeedofslowharddrivers,ortoaddressmoreRAMthantheprocessorwasdesignedtoaccess.(3)ItextendsthePCIchannelfromtheserveracrosstheLANlink,effectivelyimportingthePCIbusintotheswitchitself.(4)BylookingontotheHTTPpayloaddowntotheURLandcookie,aWebswitchknowswhatcontentisbeingrequested.(5)Inconsideringgigabit-persecondupgradesforserversandpowerworkstations,usersmustselectGigabitEthernetNICscarefully.Ⅳ.TranslatethefollowingparagraphsintoChinese:

SomeGigabitEthernetswitcheswilltakeasimplebandwidthapproach,dramaticallyloweringthecostoflarge,fatpipessonetworkscanbeeconomicallyoverengineeredtosatisfymosttrafficneeds.OtherswillimplementenhancedQoSandbroadcastreductioncapabilitiesbasedonthependingReal-timeTransferProtocolandResourceReservationProtocolstandards.

DeployingtheseswitcheswillrequiresignificanttestingtoensureinteroperabilitywithexistingLayer3equipment,whiledeterminingeaseofconfigurationandnetmanageability.Thesimpler,high-bandwidthapproachcanbeaneasiertacticalsolutionintheshortterm,butovertime,GigabitEthernetswitchesmustintegratestandardsbasedtrafficmanagementandLayer3switchingtechnologiestoscaleupinlargenets.ReadingMaterialsGigabitEthernet(Ⅰ)

Theearliestswitchingproductswillbedifferentiatedalongobviouslines:SomewillsimplyofferGigabitEthernetports;otherswillbeengineeredtocopeinternallywithtrafficloads.

Inotherwords,someproductswillmerelyaggregateseveralFastEthernetlinksontoasingleGigabitEthernetinterfaceand,therefore,requireonlyseveralhundredmegabitsper-secondofthroughput.ThesearebasicallyupgradedFastEthernetproducts,andarebestdeployedaroundtheedgeofagigabitcore.Otherswitchingproductswillbedesignedtosupportgigabitsofthroughputacrossmultipleports.

TheroleofaGigabitEthernetswitchisinherentlydifferentfromthatofits10Mand100Mbit/seccounterparts,andthereliesinthemaindifferenterofthisproductclass.

WithgigabittrafficstreamsfunnelingthroughtheLANbackbone,carryingamixofdata,graphics,voiceanvideoexchange,backboneswitcheshavetoassumethemantleofhigh-endfunctionality.Trafficmanagement,congestioncontrolandquality-of-service(QoS)issuesthatuntilrecentlyfellonATM’slapnowbecomeGigabitEthernet’sconcern.NewWordsandExpressions

trafficload流量负载upgradedadj.升级的gigabitn.千兆位

throughputn.吞吐量trafficmanagement流量控制congestioncontrol拥塞控制QoS(quality-of-service)服务质量Question

WhichquestionsarebecomingGigabitEthernet’sconcern?GigabitEthernet(Ⅱ)

SomeGigabitEthernetswitcheswilltakeasimplebandwidthapproach,dramaticallyloweringthecostoflarge,fatpipessonetworkscanbeeconomicallyoverengineeredtosatisfymosttrafficneeds.Ot