《計算機專業(yè)英語》課件第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.優(yōu)美的timelyadj.及時的scalingn.圖像縮放superchargev.增加負荷entailv.承擔(dān)robustadj.堅固的evaluatev.估價aggregatev.聚集segmentn.圖段repeatern.轉(zhuǎn)發(fā)器routern.路由器upgradev.使升級workstationn.工作站burstn.脈沖,突發(fā)consumev.消耗orchestratev.編管弦樂曲featurev.起重要作用alignv.排列eliminatev.消除interruptv.中斷issuen.問題alterv.轉(zhuǎn)變therebyadv.因此scalabilityn.可伸縮性inherentadj.固有的efficientlyadv.有效地configurev.配置adaptiveadj.適應(yīng)的PhrasesandExpressions

GigabitEthernet千兆位以太網(wǎng)fitinto符合keepupwith跟上applyto適合,適應(yīng)aswellas還有,和,并且TheExplanationofDifficultStatements

1.Althoughitshouldreadilyfitintoexistingnetworksandbeeasylouseandmanage,thissuperchargedEthernettechnologyentailsmuchmorerobustproductengineering.

分析:此句為although引導(dǎo)的讓步狀語從句,譯為“雖然……但是……”。

句意:雖然它應(yīng)該很容易地適應(yīng)已有的網(wǎng)絡(luò),容易使用和管理,但這個優(yōu)越的以太網(wǎng)技術(shù)需要很多更扎實的產(chǎn)品工程設(shè)計。

2.Here’salookatthetypesofGigabitEthernetproductsthatwillappearinthemarketbymid1997andwhatusersshouldlookforinevaluatingtheseproducts.

分析:此句中的“and”連接兩個并列賓語?！皐hatusersshouldlookforinevaluatingtheseproducts”為名詞性從句作賓語。

句意:這里讓我們來看一看到1997年市場上將出現(xiàn)的千兆位以太網(wǎng)產(chǎn)品的類型以及用戶應(yīng)選擇哪類產(chǎn)品進行評估。

3.At1Gbit/sec,CPUscannotkeepupwithnetworkthroughputunlesstheNICprovidesintelligent,hostassistfunctions.

分析:此句中“unlesstheNICprovidesintelligent,hostassistfunctions”為條件狀語從句,譯為“除非”或“如果……不……”。句意:在1千兆位/秒的速度上,除非網(wǎng)卡提供了智能的、受主機輔助的功能,否則CPU就跟不上網(wǎng)絡(luò)的吞吐量。

4.Withthe32bitPCIbus,computershavethecapacitytobursttrafficat1Gbit/sec.

分析:“Withthe32bitPCIbus”句型為“with+名詞/名詞短語”用作狀語,說明方式、條件、伴隨情況等。例如:TomdidhishomeworkwiththeTVon.

句意:有了32位PCI總線,計算機就擁有將信息流量提升到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”為現(xiàn)在分詞作定語,其中又包含that所引導(dǎo)的定語從句。

句意:千兆位以太網(wǎng)需要第三代適配器,具有板上裝有完成智能的專為主機卸載功能的精簡指令集(RISC)處理器。

6.Thisallowsfor“adaptive”interruptsthatvaryinfrequencydependingonthenet’sburst

volume.

分析:“dependingonthenet’sburstvolume”為現(xiàn)在分詞作狀語,“dependon”意為“依靠、依據(jù)”。

句意:這就允許依據(jù)網(wǎng)上脈沖數(shù)量多少而不斷改變頻率的“自適應(yīng)”中斷。

7.IntelligentGigabitEthernetadapterswillevaluatenetactivitytodeterminewhichmethodtouseatwhichtime.

分析:“whichmethodtouse”結(jié)構(gòu)為“特殊疑問詞+動詞不定式”。例如:Idon’tknowwhattodoandhowtodo.

句意:智能千兆位以太網(wǎng)適配器將評估網(wǎng)上活動,以確定在何時利用何種方法。GrammarTranslationskills專業(yè)縮略詞的翻譯

在英文的科技書刊中,很多術(shù)語往往以縮略詞的形式出現(xiàn)。但過多的科技縮語的出現(xiàn),不免會讓讀者感到困惑,往往要花費大量時間去尋找其出處,因此在專業(yè)縮略詞翻譯成中文時應(yīng)作適當處理,以便于閱讀。

1)對于通行的科技縮略語可直接照抄于譯文中。有些常用縮略語已為人們普遍接受和了解,不加注解也不致造成誤解,這時在翻譯時可直接抄錄。例如:

InmostcommercialAMbroadcastreceiversofthesuperheterodynetype,theintermediatefrequencyis465kHz.多極民用ＡＭ波超外差接收機中頻是465kHz.

ThedatestructureusedinanSNAnetworkisSDIC.

SNA網(wǎng)絡(luò)中所用的數(shù)據(jù)結(jié)構(gòu)是ＳＤＬＣ。

2)直接譯出原文中的縮略詞,有些縮略詞中文譯文并不長或作者為使原文簡練而自行采用的略語,并無普遍意義。這時最好直接采用中文譯出。例如:

FollowingtheIFisadetector

中頻線路之后接有一個檢波器。ＣＣＣisalsocontainedinthesystembasebandequipment

呼叫連接群集器也包括在系統(tǒng)基帶設(shè)備中。

3)引用縮略語加適當注釋當縮略語譯文語意太長,而引用縮略語確實能使譯文簡練時可在縮略詞第一次出現(xiàn)時加以適當注釋。注解辦法可以采用“正文頭注”,或采用“腳注”等辦法。例如:ＨＮＳ’PESnetworkisahighlyadvancedVSATtransmissionsystemthatiscapableofsupportinginteractive,batch,andLANtrafficbetweenremoteuserequipmentandhostfacilities,orbetweenanytworemotes.譯法１:ＨNS’PES(HughesNetworkSystem,Jnc,PersonalEarthStation)網(wǎng)是一個高度先進的ＶＳＡＴ(VerySmallApertureTerminal)傳輸系統(tǒng),它可以在遠端用戶設(shè)備和主站設(shè)備之間或任何兩個遠端用戶之間支持交互型業(yè)務(wù)、批量數(shù)據(jù)傳輸業(yè)務(wù)和ＬＡＮ業(yè)務(wù)。譯法２:ＨＮＳ’PES(體斯公司個人地球站)網(wǎng)是一個高度先進的ＶＳＡＴ(微口徑終端)傳輸系統(tǒng),它可以在遠端用戶設(shè)備和主站設(shè)備之間或任何兩個遠端用戶之間支持交互型業(yè)務(wù)、批量數(shù)據(jù)傳輸業(yè)務(wù)和局域網(wǎng)業(yè)務(wù)。譯法３:體斯公司個人地球站(ＨＮＳ’PES)網(wǎng)是一個高度先進的微口徑終端(ＶＳＡＴ)傳輸系統(tǒng),它可以在遠端用戶設(shè)備和主站設(shè)備之間或任何兩個遠端用戶之間支持交互型業(yè)務(wù)、批量數(shù)據(jù)業(yè)務(wù)和局域網(wǎng)(ＬＡＮ)業(yè)務(wù)。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流量負載upgradedadj.升級的gigabitn.千兆位

throughputn.吞吐量trafficmanagement流量控制congestioncontrol擁塞控制QoS(quality-of-service)服務(wù)質(zhì)量Question

WhichquestionsarebecomingGigabitEthernet’sconcern?GigabitEthernet(Ⅱ)

SomeGigabitEthernetswitcheswilltakeasimplebandwidthapproach,dramaticallyloweringthecostoflarge,fatpipessonetworkscanbeeconomicallyoverengineeredtosatisfymosttrafficneeds.Ot