大学计算机基础课程总结英文

1、Summary,考试安排,时间12月20日，周日上午，90分钟课程答疑12月16日（周三）晚11-12节；地点：1-106平时作业所有作业+实验报告必须在12月20日前全部在在线教室提交,考试安排,考题类型Termmatching（5题10分）Multiplechoice（10题20分）Completion（10题10分）Computation（2题12分）Flowchart（1题8分）,Outline,ComputerSystemHardwareSoftwareDatarepresentationincomputerNetworkAlgorithmdesignDatabaseSecurity

2、,5,Definition,Acomputerisanelectronicdevicewhichoperatesunderthecontrolofstoredinstructionsacceptsdatainputprocessesthedataaccordingtospecifiedrulesproducesandstoresoutput,Whatscomputer,6,AcomputerspowerisderivedfromSpeedReliabilityAccuracyStorageCommunications,Whatscomputer,Hardware,VonNeumannmachi

3、ne,FoundationofmoderncomputersUsebinaryinformationTheprincipleofstoredprogramTwostepsofamachinecycle:InstructioncycleandexecutioncycleFivebasiccomponentsControlUnitArithmetic/logicUnit(ALU)InputdevicesOutputdevicesStorageprimaryandsecondarystorage,Hardware,SystemUnit(主机),MotherboardProcessorCPUALUCo

4、ntrolUnitMemoryRAM,ROM,CMOS,CacheAlldataandinstructionsmustbeloadedintoRAMbeforetheycanbeexecutedBusdatahighwaybetweendevicesExpansionslots/cards(扩展槽/卡)toaddextradevicesvideocard,soundcard,networkcardPort(端口)aplugforacablethatleadstoadeviceusbports,RJ-45,VGAportformonitor,Hardware,CPUperformance,Clo

5、ckratefrequencyfordatatransportandinstructionexecutionWordsizenumberofbitstheCPUcanmanipulateatonetimeCacheCacheisspecialhigh-speedmemorythatgivestheCPUmorerapidaccesstodataInstructionsetsize,Hardware,SecondaryStorage,SlowerCommunicatewithmemory(RAM)Nonvolatile,permanentstorageCheapIncludes:Floppydi

6、skHarddiskTapeOpticaldiskCD/DVDFlashdiskDifferencebetweenthesesecondarystorage,Software,SoftwareCategories,SystemsoftwareTomanageacomputersystematafundamentallevelConsistsoftheprogramsthatcontroltheoperationsofthecomputeranditsdevicesOperatingsystemUtilityprogramApplicationsoftwareTosolveproblemsint

7、herealworld,Software,Operatingsystem,Programs/Softwaremanagecomputerresources,MemorymanagementProcessmanagementCPUschedulingprovideaninterfacebetweenusersandthecomputer,command-lineinterfacegraphicaluserinterface(GUI)allowanapplicationprogramtointeractwithothersystemresourcesSingleuserotherwise,over

8、flowoccursRealvalue:thedecimalvalueofamachinenumberMachinenumber:CodeofnumberandthesignTiptopdigitofbinarynumbershowthesign;0for“+”,1for“-”OriginalcodeandComplementcode,todosubtractioninadditionComplement=Modulus+Original,ORForpositivenumber：complement=originalFornegativenumber:Original:signbitis1,t

9、herestisitsabsolutevalueComplement:reversealldigitsexceptthesign,theplus1Complementofcomplement=originalComputationiscarriedoutintheformofComplementcode,Datarepresentation,Codeofcharacters,ASCIIcharactersetStandard7-bits,with128charactersExtended8-bits,with256charactersUnicode16-bits,asupersetofASCI

10、I,Datarepresentation,Multimediadata,Alldataareconvertedfromanalogtodigitalbeforetheyarehandledbycomputer.Soundissampled;highersamplingratemeansbetterqualityImageisrepresentedbypixels;higherresolutionmeansbetterqualityColorissimulatedbyRGBmixture.Eachpixelisnormallyrecordedbythreebytes,forred-green-b

11、luerespectively.Therefore,apixeliswrittenas(r,g,b),where0=r,g,b=255VideoisacontinuousanimationofimagesStoragerequirementforuncompressedmediaDatacompressiontosavestorageLosslesscompressionLossycompression,ComputernetworkAcollectionofcomputingdevicesconnectedinordertocommunicateandshareresourcesConnec

12、tionscanbephysicalusingwiresorcableswirelessusingradiowavesorinfraredsignalsBandwidth（带宽）Thetransmissioncapacityofacommunicationchannel.Definesthenumberofbitsthatcanbetransmittedinafixedamountoftime,usuallybps(bitspersecond)Thehigher,thefaster.,Network,Modemsconnectuserstothepublictelephonesystemfor

13、internetaccessNetworkinterfacecards(NIC)connectdevicestonetworksHubs/Switches:acentralpointforcablestoconnectseveralnodesofalocalareanetworkRouter:connectsmultiplenetworks,includingthosewithdifferentprotocols.Itcansend(route)communicationtraffictotheappropriatenetworkusingthefastestavailablepath.Med

14、ia:Twisted-paircable,Coaxialcable,Fiber-Opticcable,Radiowave,Network,Networkhardware,Network,Networktopologies（拓扑结构）,Busnetwork:consistsofasinglecentralcable,towhichallcomputersandotherdevicesconnectRingnetwork:acableformsaclosedring,orloop,withallcomputersanddevicesarrangedalongtheringStarnetwork:A

15、lldevicesinthenetworkconnecttoacentralconnectionpoint(hub),thusformingastarHybridnetwork,Network,Networktypes,Local-areanetwork(LAN)Peer-to-peernetworkClient/ServernetworkMetropolitanAreaNetwork(MAN城域网)WideAreaNetwork(WAN),Communicationprotocols,Aprotocolisasetofrulesandproceduresforexchanginginform

16、ationamongcomputers.OSIReferenceModelwith7layersTCP/IP,asetofprotocolsusedtomanagethetransmissionofdatabybreakingitupintopacketsinInternet,Network,NetworkSecurity,FirewallHardwareorsoftwareusedtoprotectanetworkbyfilteringthetrafficitallowsAccesscontrolpolicyAsetofrulesestablishedbyanorganizationthat

17、specifywhattypesofnetworkcommunicationarepermittedanddenied,NetworkAddress,IPaddressEachnetworkhasitsownsetofIPaddressesEachdevicehasitsownIPaddress.UniqueinthesamenetworkAnaddressmadeupof4bytesofnumericvaluesseparatedbydotsthatuniquelyidentifiesacomputerontheInternetInaprivatenetworkanyaddressescan

18、beused,butpublicaddressusedontheInternetmustbecentrallyassigned,27,FourkeyconfigurationsIPaddressSubnetmaskGatewayDNSserver,Network,Network,Internet,AnetconnectingallkindsofnetworkPacketswitchingMessagesaredividedintofixed-sized,numberedpackets;packetsareindividuallyroutedtotheirdestination,thenreas

19、sembledEachresourceonInternethasauniqueaddress,calledaUniformResourceLocator(统一资源定位器URL).AURLconsistsofaprotocol,adomainname,andsometimesthepathtoaspecificwebresourceServicesEmail:SMTPserverforsending,POP/IMAPserverforreceivingFileTransferProtocol(文件传输协议FTP)Cookie:Asmalltextfilethatawebserverstoreso

20、nyourlocalcomputersharddisk;itsusedforcustomizedvisit,notharmfulSearchengine:useskeywordstofindinformationontheinternetandreturnsalistofrelevantdocuments,EachdeviceisidentifiedbyitsIPaddressAdomainnameisbondedwithanIPaddress,torelaxusersfrommemorizinglongsequenceofnumbers.Domainnamesareregistered(注册

21、)inthedomainnamesystem(DNS),andwillbetranslatedtoIPaddressbydomainnamesystemservers(DNSservers).,Network,IPaddressanddomainname,BrowsersisasoftwareprogramthatrunsonyourcomputerandhelpsyouaccessWebpages,Browser,30,TheWorldWideWeb,WorldWideWeb(WWW)isaninfrastructureofdistributedinformationcombinedwith

22、softwarethatusesnetworksasavehicletoexchangethatinformationWebpagesarecreatedusingalanguagecalledtheHypertextMarkupLanguage,orHTMLSpecifictagsareinsertedintoadocumenttodefinethedisplayformatoftheinformationLateststandisHTML5Web2.0isaplatformenablingeveryonetoparticipateandcontribute.,Problemsolvingp

23、hases,AlgorithmDesign,AlgorithmDesign,AsetofunambiguousinstructionsforsolvingaproblemorsubprobleminafiniteamountoftimeusingafiniteamountofdataWaystofindanalgorithmAskquestionstounderstandtheproblemLookforfamiliarthingsDivideandconquer,Algorithm,AlgorithmDesign,BasicstructureofaprogramSequenceSelecti

24、onLoopFlowchartPseudocode,Algorithm,accumulator,counter,AlgorithmDesign,Calculatetheaveragescoreof10students,ThescoreofeachstudentisK.UseTtosavethetotalscore，useIfortheithstudent(I=1，2，10),AlgorithmDesign,Aprogramminglanguageisasetofwords,symbols,andcodesthatenablesaprogrammertocommunicateasolutiona

25、lgorithmtothecomputerClassificationLow-levelmachinecode:machinelanguage,High-levelsourcecode:procedurallanguage,object-orientedCompilerandinterpreterAcomputersmicroprocessoronlyunderstandsmachinelanguage.Therefore,instructionwritteninahigh-levellanguagemustbetranslatedintomachinelanguagebeforeacompu

26、tercanusethem,Computerlanguages,AlgorithmDesign,convertsthecompletehigh-levellanguageprogram,calledthesourcecode,intoamachinelanguagecode,calledtheobjectcode.Thisobjectcodecanthenbesavedandrunlater.,Compiler,convertsthehigh-levellanguageprogramonestatementatatimeintomachinecodejustbeforeitistobeexec

27、uted.Noobjectcodeissaved,Interpreter,DBMS,DatabaseAstructuredsetofdataDatabasemanagementsystem(DBMS)Acombinationofsoftwareanddataaphysicaldatabase:Acollectionoffilesthatcontainthedataadatabaseschema:Aspecificationofthelogicalstructureofthedatastoredinthedatabaseadatabaseengine:Softwarethatsupportsac

28、cesstoandmodificationofthedatabasecontents,DBMS,Addingnew,emptyfilestothedatabaseRemovingexistingfilesfromthedatabaseInsertingdataintoexistingfilesDeletingdatafromexistingfilesChangingdatainexistingfilesRetrievingdatafromexistingfiles,Setofprogramstoaccessthedata:operations,ThemostpopulartoolsforRelationaldatabase:SQLStructuredQueryLanguage,DBMS,Entity-RelationshipmodelAnentityisanobjectthatexistsand