外文翻译关于Linux的介绍(Introduction-to-Linux)

毕业设计说明书英文文献及中文翻译1021040330 学生姓名： 学号： 软件工程学 院： 专 业： 指导教师： 2014 年 6 月Introduction to Linux1.1 History1.1.1 UNIXInordertounderstandthepopularityofLinux,weneedtotravelbackintime,about30yearsago.Imaginecomputersasbigashouses,evenstadiums.Whilethesizesofthosecomputersposedsubstantialproblems,therewasonethingthatmadethisevenworse:everycomputerhadadifferentoperatingsystem.Softwarewasalwayscustomizedtoserveaspecificpurpose,andsoftwareforonegivensystemdidntrunonanothersystem.Beingabletoworkwithonesystemdidntautomaticallymeanthatyoucouldworkwithanother.Itwasdifficult,bothfortheusersandthesystemadministrators.Computerswereextremelyexpensivethen,andsacrificeshadtobemadeevenaftertheoriginalpurchasejusttogettheuserstounderstandhowtheyworked.ThetotalcostofITwasenormous.Technologicallytheworldwasnotquitethatadvanced,sotheyhadtolivewiththesizeforanotherdecade.In1969,ateamofdevelopersintheBellLabslaboratoriesstartedworkingonasolutionforthesoftwareproblem,toaddressthesecompatibilityissues.Theydevelopedanewoperatingsystem,whichwassimpleandelegantwrittenintheCprogramminglanguageinsteadofinassemblycodeabletorecyclecode.TheBellLabsdevelopersnamedtheirprojectUNIX.Thecoderecyclingfeatureswereveryimportant.Untilthen,allcommerciallyavailablecomputersystemswerewritteninacodespecificallydevelopedforonesystem.UNIXontheotherhandneededonlyasmallpieceofthatspecialcode,whichisnowcommonlynamedthekernel.ThiskernelistheonlypieceofcodethatneedstobeadaptedforeveryspecificsystemandformsthebaseoftheUNIXsystem.Theoperatingsystemandallotherfunctionswerebuiltaroundthiskernelandwritteninahigherprogramminglanguage,C.ThislanguagewasespeciallydevelopedforcreatingtheUNIXsystem.Usingthisnewtechnique,itwasmucheasiertodevelopanoperatingsystemthatcouldrunonmanydifferenttypesofhardware.Thesoftwarevendorswerequicktoadapt,sincetheycouldselltentimesmoresoftwarealmosteffortlessly.Weirdnewsituationscameinexistence:imagineforinstancecomputersfromdifferentvendorscommunicatinginthesamenetwork,orusersworkingondifferentsystemswithouttheneedforextraeducationtouseanothercomputer.UNIXdidagreatdealtohelpusersbecomecompatiblewithdifferentsystems.ThroughoutthenextcoupleofdecadesthedevelopmentofUNIXcontinued.MorethingsbecamepossibletodoandmorehardwareandsoftwarevendorsaddedsupportforUNIXtotheirproducts.UNIXwasinitiallyfoundonlyinverylargeenvironmentswithmainframesandminicomputers(notethataPCisamicrocomputer).Youhadtoworkatauniversity,forthegovernmentorforlargefinancialcorporationsinordertogetyourhandsonaUNIXsystem.Butsmallercomputerswerebeingdeveloped,andbytheendofthe80s,manypeoplehadhomecomputers.Bythattime,therewereseveralversionsofUNIXavailableforthePCarchitecture,butnoneofthemweretrulyfree.1.1.2 CurrentapplicationofLinuxsystemsTodayLinuxhasjoinedthedesktopmarket.Linuxdevelopersconcentratedonnetworkingandservicesinthebeginning,andofficeapplicationshavebeenthelastbarriertobetakendown.WedontliketoadmitthatMicrosoftisrulingthismarket,soplentyofalternativeshavebeenstartedoverthelastcoupleofyearstomakeLinuxanacceptablechoiceasaworkstation,providinganeasyuserinterfaceandMScompatibleofficeapplicationslikewordprocessors,spreadsheets,presentationsandthelike.Ontheserverside,Linuxiswell-knownasastableandreliableplatform,providingdatabaseandtradingservicesforcompanieslikeAmazon,thewell-knownonlinebookshop,USPostOffice,theGermanarmyandsuch.EspeciallyInternetprovidersandInternetserviceprovidershavegrownfondofLinuxasfirewall,proxy-andwebserver,andyouwillfindaLinuxboxwithinreachofeveryUNIXsystemadministratorwhoappreciatesacomfortablemanagementstation.ClustersofLinuxmachinesareusedinthecreationofmoviessuchasTitanic,Shrekandothers.Inpostoffices,theyarethenervecentersthatroutemailandinlargesearchengine,clustersareusedtoperforminternetsearches.Theseareonlyafewofthethousandsofheavy-dutyjobsthatLinuxisperformingday-to-dayacrosstheworld.ItisalsoworthtonotethatmodernLinuxnotonlyrunsonworkstations,mid-andhigh-endservers,butalsoongadgetslikePDAs,mobiles,ashiploadofembeddedapplicationsandevenonexperimentalwristwatches.ThismakesLinuxtheonlyoperatingsystemintheworldcoveringsuchawiderangeofhardware.1.2Theuserinterface1.2.1 IsLinuxdifficult?WhetherLinuxisdifficulttolearndependsonthepersonyoureasking.ExperiencedUNIXuserswillsayno,becauseLinuxisanidealoperatingsystemforpower-usersandprogrammers,becauseithasbeenandisbeingdevelopedbysuchpeople.Everythingagoodprogrammercanwishforisavailable:compilers,libraries,developmentanddebuggingtools.ThesepackagescomewitheverystandardLinuxdistribution.TheC-compilerisincludedforfree,allthedocumentationandmanualsarethere,andexamplesareoftenincludedtohelpyougetstartedinnotime.ItfeelslikeUNIXandswitchingbetweenUNIXandLinuxisanaturalthing.IntheearlydaysofLinux,beinganexpertwaskindofrequiredtostartusingthesystem.ItwascommonpracticetotellabeginningusertoRTFM(readthemanuals).Whilethemanualswereoneverysystem,itwasdifficulttofindthedocumentation,andevenifsomeonedid,explanationswereinsuchtechnicaltermsthatthenewuserbecameeasilydiscouragedfromlearningthesystem.TheLinux-usingcommunitystartedtorealizethatifLinuxwasevertobeanimportantplayerontheoperatingsystemmarket,therehadtobesomeseriouschangesintheaccessibilityofthesystem.1.2.2 Linuxfornon-experiencedusersCompaniessuchasRedHat,SuSEandMandrakehavesprungup,providingpackagedLinuxdistributionssuitableformassconsumption.Theyintegratedagreatdealofgraphicaluserinterfaces(GUIs),developedbythecommunity,inordertoeasemanagementofprogramsandservices.AsaLinuxusertodayyouhaveallthemeansofgettingtoknowyoursysteminsideout,butitisnolongernecessarytohavethatknowledgeinordertomakethesystemcomplytoyourrequests.Nowadaysyoucanlogingraphicallyandstartallrequiredapplicationswithoutevenhavingtotypeasinglecharacter,whileyoustillhavetheabilitytoaccessthecoreofthesystemifneeded.Becauseofitsstructure,Linuxallowsausertogrowintothesystem:itequallyfitsnewandexperiencedusers.Newusersarenotforcedtododifficultthings,whileexperiencedusersarenotforcedtoworkinthesamewaytheydidwhentheyfirststartedlearningLinux.Whiledevelopmentintheserviceareacontinues,greatthingsarebeingdonefordesktopusers,generallyconsideredasthegroupleastlikelytoknowhowasystemworks.Developersofdesktopapplicationsaremakingincredibleeffortstomakethemostbeautifuldesktopsyouveeverseen,ortomakeyourLinuxmachinelookjustlikeyourformerMSWindowsorMacIntoshworkstation.Thelatestdevelopmentsalsoinclude3DaccelerationsupportandsupportforUSBdevices,single-clickupdatesofsystemandpackages,andsoon.Linuxhasthese,andtriestopresentallavailableservicesinalogicalformthatordinarypeoplecanunderstand.1.3 DoesLinuxhaveafuture?1.3.1 OpenSourceTheideabehindOpenSourcesoftwareisrathersimple:whenprogrammerscanread,distributeandchangecode,thecodewillmature.Peoplecanadaptit,fixit,debugit,andtheycandoitataspeedthatdwarfstheperformanceofsoftwaredevelopersatconventionalcompanies.Thissoftwarewillbemoreflexibleandofabetterqualitythansoftwarethathasbeendevelopedusingtheconventionalchannels,becausemorepeoplehavetesteditinmoredifferentconditionsthantheclosedsoftwaredeveloperevercan.TheOpenSourceinitiativestartedtomakethiscleartothecommercialworld,andveryslowly,commercialvendorsarestartingtoseethepoint.Whilelotsofacademicsandtechnicalpeoplehavealreadybeenconvincedfor20yearsnowthatthisisthewaytogo,commercialvendorsneededapplicationsliketheInternettomakethemrealizetheycanprofitfromOpenSource.NowLinuxhasgrownpastthestagewhereitwasalmostexclusivelyanacademicsystem,usefulonlytoahandfulofpeoplewithatechnicalbackground.NowLinuxprovidesmorethantheoperatingsystem:thereisanentireinfrastructuresupportingthechainofeffortofcreatinganoperatingsystem,ofmakingandtestingprogramsforit,ofbringingeverythingtotheusers,ofsupplyingmaintenance,updatesandsupportandcustomizations,etcetera.Today,Linuxisreadytoacceptthechallengeofafast-changingworld.1.3.2 TenyearsofexperienceatyourserviceWhileLinuxisprobablythemostwell-knownOpenSourceinitiative,thereisanotherprojectthatcontributedenormouslytothepopularityoftheLinuxoperatingsystem.ThisprojectiscalledSAMBA,anditsachievementisthereverseengineeringoftheServerMessageBlock(SMB)/CommonInternetFileSystem(CIFS)protocolusedforfile-andprint-servingonPC-relatedmachines,nativelysupportedbyMSWindowsNTandOS/2,andLinux.PackagesarenowavailableforalmosteverysystemandprovideinterconnectionsolutionsinmixedenvironmentsusingMSWindowsprotocols:Windows-compatible(uptoandincludingWin2K)file-andprint-servers.MaybeevenmoresuccessfulthantheSAMBAprojectistheApacheHTTPserverproject.TheserverrunsonUNIX,WindowsNTandmanyotheroperatingsystems.OriginallyknownasAPAtCHyserver,basedonexistingcodeandaseriesofpatchfiles,thenameforthematuredcodedeservestobeconnotedwiththenativeAmericantribeoftheApache,well-knownfortheirsuperiorskillsinwarfarestrategyandinexhaustibleendurance.Apachehasbeenshowntobesubstantiallyfaster,morestableandmorefeature-fullthanmanyotherwebservers.Apacheisrunonsitesthatgetmillionsofvisitorsperday,andwhilenoofficialsupportisprovidedbythedevelopers,theApacheusercommunityprovidesanswerstoallyourquestions.Commercialsupportisnowbeingprovidedbyanumberofthirdparties.Inthecategoryofofficeapplications,achoiceofMSOfficesuiteclonesisavailable,rangingfrompartialtofullimplementationsoftheapplicationsavailableonMSWindowsworkstations.TheseinitiativeshelpedagreatdealtomakeLinuxacceptableforthedesktopmarket,becausetheusersdontneedextratrainingtolearnhowtoworkwithnewsystems.Withthedesktopcomesthepraiseofthecommonusers,andnotonlytheirpraise,butalsotheirspecificrequirements,whicharegrowingmoreintricateanddemandingbytheday.TheOpenSourcecommunity,consistinglargelyofpeoplewhohavebeencontributingforoverhalfadecade,assuresLinuxpositionasanimportantplayeronthedesktopmarketaswellasingeneralITapplication.PaidemployeesandvolunteersalikeareworkingdiligentlysothatLinuxcanmaintainapositioninthemarket.Themoreusers,themorequestions.TheOpenSourcecommunitymakessureanswerskeepcoming,andwatchesthequalityoftheanswerswithasuspiciouseye,resultinginevermorestabilityandaccessibility.1.4 PropertiesofLinux1.4.1 LinuxProsAlotoftheadvantagesofLinuxareaconsequenceofLinuxorigins,deeplyrootedinUNIX,exceptforthefirstadvantage,ofcourse:Linuxisfree:Asinfreebeer,theysay.Ifyouwanttospendabsolutelynothing,youdontevenhavetopaythepriceofaCD.Linux can be downloaded for free from the internet.Noregistrationfees,nocostsperuser,freeupdates,andfreelyavailablesourcecodeincaseyouwanttochangethebehaviorofyoursystem.Mostofall,Linuxisfreeasinfreespeech:ThelicensecommonlyusedistheGNUPublicLicense(GPL).Thelicensesaysthatanybodywhomaywanttodoso,hastherighttochangeLinuxandeventuallytoredistributeachangedversion,ontheoneconditionthatthecodeisstillavailableafterredistribution.Inpractice,youarefreetograbakernelimage,forinstancetoaddsupportforteletransportationmachinesortimetravelandsellyournewcode,aslongasyourcustomerscanstillhaveacopyofthatcode.Linuxisportabletoanyhardwareplatform:AvendorwhowantstosellanewtypeofcomputerandwhodoesntknowwhatkindofOShisnewmachinewillrun(saytheCPUinyourcarorwashingmachine),cantakeaLinuxkernelandmakeitworkonhishardware,becausedocumentationrelatedtothisactivityisfreelyavailable.Linuxwasmadetokeeponrunning:AswithUNIX,aLinuxsystemexpectstorunwithoutrebootingallthetime.Thatiswhyalotoftasksarebeingexecutedatnightorscheduledautomaticallyforothercalmmoments,resultinginhigheravailabilityduringbusierperiodsandamorebalanceduseofthehardware.ThispropertyallowsforLinuxtobeapplicablealsoinenvironmentswherepeopledonthavethetimeorthepossibilitytocontroltheirsystemsnightandday.Linuxissecureandversatile:ThesecuritymodelusedinLinuxisbasedontheUNIXideaofsecurity,whichisknowntoberobustandofprovenquality.ButLinuxisnotonlyfitforuseasafortagainstenemyattacksfromtheInternet:itwilladaptequallytoothersituations,utilizingthesamehighstandardsforsecurity.Yourdevelopmentmachineorcontrolstationwillbeassecureasyourfirewall.Linuxisscalable:FromaPalmtopwith2MBofmemorytoapetabytestorageclusterwithhundredsofnodes:addorremovetheappropriatepackagesandLinuxfitsall.Youdontneedasupercomputeranymore,becauseyoucanuseLinuxtodobigthingsusingthebuildingblocksprovidedwiththesystem.Ifyouwanttodolittlethings,suchasmakinganoperatingsystemforanembeddedprocessororjustrecyclingyourold486,Linuxwilldothataswell.TheLinuxOSandLinuxapplicationshaveveryshortdebug-times:BecauseLinuxhasbeendevelopedandtestedbythousandsofpeople,botherrorsandpeopletofixthemarefoundveryquickly.Itoftenhappensthatthereareonlyacoupleofhoursbetweendiscoveryandfixingofabug.1.4.2 LinuxConsTherearefartoomanydifferentdistributions:Quotcapites,totrationes,astheRomansalreadysaid:themorepeople,themoreopinions.Atfirstglance,theamountofLinuxdistributionscanbefrightening,orridiculous,dependingonyourpointofview.Butitalsomeansthateveryonewillfindwhatheorsheneeds.Youdontneedtobeanexperttofindasuitablerelease.Whenasked,generallyeveryLinuxuserwillsaythatthebestdistributionisthespecificversionheisusing.Sowhichoneshouldyouchoose?Dontworrytoomuchaboutthat:allreleasescontainmoreorlessthesamesetofbasicpackages.Ontopofthebasics,specialthirdpartysoftwareisaddedmaking,orexample,TurboLinuxmoresuitableforthesmallandmediumenterprise,RedHatforserversandSuSEforworkstations.However,thedifferencesarelikelytobeverysuperficial.Thebeststrategyistotestacoupleofdistributions;unfortunatelynoteverybodyhasthetimeforthis.Luckily,thereisplentyofadviceonthesubjectofchoosingyourLinux.OneplaceisLinuxJournal,whichdiscusseshardwareandsupport,amongmanyothersubjects.TheInstallationHOWTOalsodiscusseschoosingyourdistribution.Linuxisnotveryuserfriendlyandconfusingforbeginners:Inlightofitspopularity,considerableefforthasbeenmadetomakeLinuxeveneasiertouse,especiallyfornewusers.Moreinformationisbeingreleaseddaily,suchasthisguide,tohelpfillthegapfordocumentationavailabletousersatalllevels.IsanOpenSourceproducttrustworthy?Howcansomethingthatisfreealsobereliable?LinuxusershavethechoicewhethertouseLinuxornot,whichgivesthemanenormousadvantagecomparedtousersofproprietarysoftware,whodonthavethatkindoffreedom.Afterlongperiodsoftesting,mostLinuxuserscometotheconclusionthatLinuxisnotonlyasgood,butinmanycasesbetterandfasterthatthetraditionalsolutions.IfLinuxwerenottrustworthy,itwouldhavebeenlonggone,neverknowingthepopularityithasnow,withmillionsofusers.Nowuserscaninfluencetheirsystemsandsharetheirremarkswiththecommunity,sothesystemgetsbetterandbettereveryday.Itisaprojectthatisneverfinished,thatistrue,butinaneverchangingenvironment,Linuxisalsoaprojectthatcontinuestostriveforperfection.中X大学2014届毕业设计英文文献及中文翻译关于Linux的介绍1.1 历史1.1.1 UNIX为了了解Linux的历史，我们需要追溯到30年前。想象一下像房子甚至体育馆一样大的计算机。除了电脑的体积带来的问题，有一件事情让这些变得更糟糕，那就是每个计算机都有一个不同的操作系统。软件定制服务一直是一个给定系统的特定目标，软件无法在另一个系统上运行。能够在一个系统下工作并不意味着也可以自动同另一个系统共事。这些无论对于用户还是系统管理员都是非常困难的。由于计算机非常昂贵，所以人们不得不为之付出，即使购买计算机那也只是为了让用户了解他们是如何工作的。但是IT的总成本还是非常巨大的。世界上的技术还没有那么先进，因此他们不得不和如此大的计算机共同再度过十年。在1969年，贝尔实验室的开发团队人员们开始研究，为解决软件问题，更好的完善兼容性。他们开发出一种新的操作系统，就是这个。简单巧妙用C语言设计代替汇编码能够循环利用的代码。贝尔实验室开发的项目把它命名为“UNIX操作系统。”该代码循环的功能是非常重要的。在此之前，所有商用计算机系统是写在一个专门为系统开发的代码中。而UNIX只需要有一组特殊的代码，也就是现在俗称小片的内核。这个内核的代码是唯一的一块，需要为每一个特定的系统和各种形式的UNIX系统基础改编。操作系统和所有其他所有功能，都围绕这个核心，用更高级编程语言所编写的，C.这种语言是专为创造UNIX系统而发展的。使用这种新技术，更易于开发可以运行在不同类型硬件上的操作系统。软件供