flash动画教学案例设计及研究专业外文翻译.docx
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flash动画教学案例设计及研究专业外文翻译
滨州学院
专业外文翻译
题目
TheHistoryoftheInternet
系(院)
计算机科学技术系
专业
软件技术
班级
2008级3班
学生姓名
刘俊杰
学号
2008111012
指导教师
杨静
职称
助教
二〇一一年五月四日
TheHistoryoftheInternet
TheBeginning-ARPAnet
TheInternetstartedasaprojectbytheUSgovernment.Theobjectoftheprojectwastocreateameansofcommunicationsbetweenlongdistancepoints,intheeventofanationwideemergencyor,morespecifically,nuclearwar.TheprojectwascalledARPAnet,anditiswhattheInternetstartedas.Fundedspecificallyformilitarycommunication,theengineersresponsibleforARPANethadnoideaofthepossibilitiesofan"Internet."
Bydefinition,an'Internet'isfourormorecomputersconnectedbyanetwork.
ARPAnetachieveditsnetworkbyusingaprotocolcalledTCP/IP.Thebasicsaroundthisprotocolwasthatifinformationsentoveranetworkfailedtogetthroughononeroute,itwouldfindanotherroutetoworkwith,aswellasestablishingameansforonecomputerto"talk"toanothercomputer,regardlessofwhetheritwasaPCoraMacintosh.
Bythe80'sARPAnet,justyearsawayfrombecomingthemorewellknownInternet,had200computers.TheDefenseDepartment,satisfiedwithARPAnetsresults,decidedtofullyadoptitintoservice,andconnectedmanymilitarycomputersandresourcesintothenetwork.ARPAnetthenhad562computersonitsnetwork.Bytheyear1984,ithadover1000computersonitsnetwork.
In1986ARPAnet(supposedly)shutdown,butonlytheorganizationshut
down,andtheexistingnetworksstillexistedbetweenthemorethan1000
computers.ItshutdownduetoafailiedlinkupwithNSF,whowantedto
connectits5countywidesupercomputersintoARPAnet.
WiththefundingofNSF,newhighspeedlinesweresuccessfullyinstalled
atlinespeedsof56k(anormalmodemnowadays)throughtelephonelines
in1988.Bythattime,therewere28,174computersonthe(bythendecided)Internet.In1989therewere80,000computersonit.By1989,therewere290,000.
Anothernetworkwasbuilttosupporttheincrediblenumberofpeople
joining.Itwasconstructedin1992.
Today-TheInternet
Today,theInternethasbecomeoneofthemostimportanttechnologicaladvancementsinthehistoryofhumanity.Everyonewantstoget'online'toexperiencethewealthofinformationoftheInternet.MillionsofpeoplenowusetheInternet,andit'spredictedthatbytheyear2003everysinglepersonontheplanetwillhaveInternetaccess.TheInternethastrulybecomeawayoflifeinourtimeandera,andisevolvingsoquicklyitshardtodeterminewhereitwillgonext,ascomputerandnetworktechnologyimproveeveryday.
HOWITWORKS:
It'sastandardthing.PeopleusingtheInternet.Shopping,playinggames,conversinginvirtualInternetenvironments.
TheInternetisnota'thing'itself.TheInternetcannotjust"crash."Itfunctionsthesamewayasthetelephonesystem,onlythereisnoInternetcompanythatrunstheInternet.
TheInternetisacollectionofmillioinsofcomputersthatareallconnectedtoeachother,orhavethemeanstoconnecttoeachother.TheInternetisjustlikeanofficenetwork,onlyithasmillionsofcomputersconnectedtoit.
ThemainthingabouthowtheInternetworksiscommunication.HowdoesacomputerinHoustonknowhowtoaccessdataonacomputerinTokyotoviewawebpage?
Internetcommunication,communicationamongcomputersconnectedtotheInternet,isbasedonalanguage.ThislanguageiscalledTCP/IP.TCP/IPestablishesalanguageforacomputertoaccessandtransmitdataovertheInternetsystem.
ButTCP/IPassumesthatthereisaphysicalconnecetionbetweenonecomputerandanother.Thisisnotusuallythecase.TherewouldhavetobeanetworkwirethatwenttoeverycomputerconnectedtotheInternet,butthatwouldmaketheInternetimpossibletoaccess.
Thephysicalconnectionthatisrequireedisestablishedbywayofmodems,phonelines,andothermodemcableconnections(likecablemodemsorDSL).Modemsoncomputersreadandtransmitdataoverestablishedlines,whichcouldbephonelinesordatalines.Theactualhardcoreconnectionsareestablishedamongcomputerscalledrouters.
Arouterisacomputerthatservesasatrafficcontrollerforinformation.
Toexplainthisbetter,let'slookathowastandardcomputermightviewawebpage.
1.Theuser'scomputerdialsintoanInternetServiceProvider(ISP).TheISPmightinturnbeconnectedtoanotherISP,orastraightconnectionintotheInternetbackbone.
2.TheuserlaunchesawebbrowserlikeNetscapeorInternetExplorerandtypesinaninternetlocationtogoto.
3.Here'swherethetrickypartcomesin.First,thecomputersendsdataaboutit'sdatarequesttoarouter.Arouterisaveryhighspeedpowerfulcomputerrunningspecialsoftware.Thecollectionofroutersintheworldmakewhatiscalleda"backbone,"onwhichallthedataontheInternetistransferred.Thebackbonepresentlyoperatesataspeedofseveralgigabytesper-second.Suchaspeedcomparedtoanormalmodemislikecomparingtheheatofthesuntotheheatofanice-cube.
Routershandledatathatisgoingbackandforth.Arouterputssmallchunksofdataintopackagescalledpackets,whichfunctionsimilarlytoenvelopes.So,whentherequestforthewebpagegoesthrough,itusesTCP/IPprotocolstotelltherouterwhattodowiththedata,whereit'sgoing,andoverallwheretheuserwantstogo.
4.Theroutersendsthesepacketstootherrouters,eventuallyleadingtothetargetcomputer.It'slikewhisperdownthelane(onlytheinformationremainsintact).
5.Whentheinformationreachesthetargetwebserver,thewebserverthenbeginstosendthewebpageback.Awebserveristhecomputerwherethewebpageisstoredthatisrunningaprogramthathandlesrequestsforthewebpageandsendsthewebpagetowhoeverwantstoseeit.
6.Thewebpageisputinpackets,sentthroughrouters,andarriveattheuserscomputerwheretheusercanviewthewebpageonceitisassembled.
Thepacketswhichcontainthedataalsocontainspecialinformationthatletsroutersandothercomputersknowhowtoreassemblethedataintherightorder.
Withmillionsofwebpages,andmillionsofusers,usingtheInternetisnotalwayseasyforabeginninguser,especiallyforsomeonewhoisnotentirelycomfortalewithusingcomputers.BelowyoucanfindtipstricksandhelponhowtousemainservicesoftheInternet.
Beforeyouaccesswebpages,youmusthaveawebbrowsertoactuallybeabletoviewthewebpages.MostInternetAccessProvidersprovideyouwithawebbrowserinthesoftwaretheyusuallygivetocustomers;you.Thefactthatyouareviewingthispagemeansthatyouhaveawebbrowser.ThetoptwousebrowsersareNetscapeCommunicatorandMicrosoftInternetExplorer.NetscapecanbefoundatandMSIEcanbefoundat.
Thefactthatyou'rereadingthisrightnowmeansthatyouhaveawebbrowser.
Nextyoumustbefamiliarwithactuallyusingwebpages.Awebpageisacollectionofhyperlinks,images,text,forms,menus,andmultimedia.To"navigate"awebpage,simplyclickthelinksitprovidesorfollowit'sowninstructions(likeifithasaformyouneedtouse,itwillprobablyinstructyouhowtouseit).Basically,everythingaboutawebpageismadetobeself-explanetory.Thatisthenatureofawebpage,tobeeasilynavigatable.
"Ohno!
a404error!
'Cannotfindwebpage?
'"isacommonremarkmadebynewweb-users.
Sometimeswebsiteshaveerrors.Butanerroronawebsiteisnottheuser'sfault,ofcourse.
A404errormeansthatthepageyoutriedtogotodoesnotexist.Thiscouldbebecausethesiteisstillbeingconstructedandthepagehasn'tbeencreatedyet,orbecausethesiteauthormadeatypointhepage.There'snothingmuchtodoabouta404errorexceptfore-mailingthesiteadministrator(ofthepageyouwantedtogoto)antellinghim/herabouttheerror.
AJavascripterroristheresultofaprogrammingerrorintheJavascriptcodeofawebsite.NotallwebsitesutilizeJavascript,butmanydo.JavascriptisdifferentfromJava,andmostbrowsersnowsupportJavascript.Ifyouareusinganoldversionofawebbrowser(Netscape3.0forexample),youmightgetJavascripterrorsbecausesitesutilizeJavascriptversionsthatyourbrowserdoesnotsupport.So,youcantrygettinganewerversionofyourwebbrowser.
E-mailstandsforElectronicMail,andthat'swhatitis.E-mailenablespeopletosendletters,andevenfilesandpicturestoeachother.
Tousee-mail,youmusthaveane-mailclient,whichisjustlikeapersonalpostoffice,sinceitretrievesandstorese-mail.
Secondly,youmusthaveane-mailaccount.MostInternetServiceProvidersprovidefreee-mailaccount(s)forfree.Someservicesofferfreee-mail,likeHotmail,andGeocities.
Afterconfiguringyoure-mailclientwithyourPOP3andSMTPserveraddress(youre-mailproviderwillgiveyouthatinformation),youarereadytoreceivemail.
Anattachmentisainaletter.Ifsomeonesendsyouanattachmentandyoudon'tknowwhoitis,don'trunthefile,ever.Itcouldbeavirusorsomeotherkindofnastyprograms.Youcan'tgetavirusjustbyreadinge-mail,you'llhavetophysicallyexecutesomeformofprogramforavirustostrike.
Asignatureisafeatureofmanye-mailprograms.Asignatureisaddedtotheendofeverye-mailyousendout.Youcanputatextgraphic,yourbusinessinformation,anythingyouwant.
ImaginethatacomputerontheInternetisanislandinthesea.Theseaisfilledwithmillionsofislands.ThisistheInternet.Imagineanislandcommunicateswithotherislandbysendingshipstootherislandsandreceivingships.Theislandhasportstoacceptandsendoutsh