计算机专业英语4VIP免费

unit4SecondaryStorage1-newwords:1.archivala.档案的2.cassetten.盒式磁带，盒带Cassettesareinexpensiveandcompact,buttheyarerelativelyslowanderrorprone.Theyareusedonsomesmallhomecomputersystemsorforarchivalstorage.３．mechanismn．机械装置翻译：盒带是廉价的，高密度的，但相对来说盒带的记录速度也是慢的，而且易于出错．盒带可用于一些小型的家庭计算机系统或者存储档案．pronea.易于…的drivemechanism驱动装置accessmechanism存取装置1-newwords:５.sectorn.扇区concentriccircles同心圆４.trackn.磁道Thedataarerecordedonaseriesofconcentriccirclescalledtracks.Theaccessmechanismstepsfromtracktotrack,readingorwritingoneatatime.Thetracksaresubdividedintosectors;itisthecontentsofasectorthatmovebetweenthedisketteandmainmemory.Todistinguishthesectors,theyareaddressedbynumberingthemsequentially-0,1,2,andsoon.翻译：数据记录在称为磁道的一组同心圆上．存取装置从一个磁道步进到另一个磁道，一次只能读／写一个磁道．把磁道再分成扇区，在软盘和主存间传送的就是一个扇区的内容．为了区别扇区，用０，１，２…等给扇区按顺序地编上地址号．tracksector1-newwords:6.cushionn.垫子,缓冲物acushionofair空气缓冲垫7.consecutivea.连续的，符合逻辑次序的．8.indexn.索引9.directoryn.目录10.jacketn.夹克，外衣，保护衣DiskettesThediskjackethasfouropenings:(1)hub(2)dataaccessarea(3)write/protectnotch(4)indexhole(1)(4)(2)(3)2-pleaseremembertothetechnicalterms1.seektime查找时间Thetimeneededtopositionadisk’saccessmechanismoveraspecifictrack.2.rotationaldelay旋转延迟Ondiskordrum,thetimerequiredforthedesiredsectortorotatetotheread/writeheadaftertheheadhasbeenpositionedoverthedesiredtrack.drum磁鼓（一种有效地辅助存储介质）positionv.把…定位翻译：把磁盘存取装置定位在某个指定的磁道上所需的时间．．翻译：对硬盘或磁鼓而言，当磁头已被定位在所要找的磁道上后，移动读写磁头寻找扇区所花的时间．2-pleaseremembertothetechnicalterms3.cylinder同位标磁道组（柱面）Onamultisurfacediskpack,onepositionoftheaccessmechanism,whichdefinesasetofseveraltracks.4.diskpack磁盘组Asetoftwoormoredisksstackedonacommondriveshaftandaccessedbyacommonsetofread/writeheads.翻译：组装在一个公共的驱动轴上并用一组公共读写磁头存取的两个或更多磁盘的集合．翻译：在多面磁盘组上，存取装置地某一位置都确定一组磁道，由若干磁道构成的一组称为同位标磁道组．Next:seethetext１．WhysecondarystorageFirst:theadvantageofthestorageOneadvantageofacomputeristhatoncedatahavebeenentered,theycanbestoredonthemachineandaccessedrepeatedly.Second:disadvantageofthemainmemoryWhereexactlyarethedataandtheprogramsstored?Theobviousanswerismainmemory.butmainmemoryisexpensive,andcapacityislimited.Anotherproblemisitsvolatility,mainmemorylosesitscontentswhenthepoweriscut.Weneedafast,accurate,inexpensive,high-capacity,nonvolatileextensionofmainmemory,andsecondarystoragefillsthisneed.翻译：用户需要用快速的、精确的、廉价的、大容量的和不易失地存储器来扩展主存储器。辅助存储器满足了这一要求。First:magneticcassette2．SecondarystoragemediaSecond:disketteThird:harddiskTheforth:othersecondarystoragemedia2．SecondarystoragemediaFirst:magneticcassetteMagneticcassettesaretheleastexpensiveofthesecondarystoragemedia,buttheyarealsorelativelyslowanderrorprone.Theyareusedonsomesmallhomecomputersystemsorforarchivalstorage.2．SecondarystoragemediaDisketteorfloppydiskisthemostcommonmicrocomputersecondarystoragemedium.Second:disketteReadingpage703.seektime查询时间4.rotationaldelay旋转延迟2.sectorn.扇区1.trackn.磁道2．Secondarystor...