计算机导论考试重点（key points of computer introduction examination）

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计算机导论考试重点（Keypointsofcomputerintroductionexamination）ThecachememoryreadandwritespeedandeasethemaincontradictionofCPUrunningspeedcannotmeettheneeds;morestoragespaceforvirtualmemorytosolvetheproblemofmemorycapacityissmall,cannotsavethelargerprogramwithmoredata,soastomaketherenovationofmemorysystemhashigherspeed,morereadingandwritinglargestoragespace,therelativelylowcostofmanufacturingandoperatingrequirements.Thepursuitofarenovatedmemorysystemwithhigherperformancepriceratioisthecoreideaofthethreelevelstoragearchitecture.Theoperatingprincipleofthememorysystemofthethreestagestructureisbasedonthelocalityprincipleoftheprogramrunning.Thelocalprincipleofprogramoperationisembodiedin:(1)thelocalprincipleoftime.Inashortperiodoftime,therecentlyaccessedprogramsanddataarelikelytobeaccessedagain.(2)theprincipleofspatiallocality.Thatis,recently,itisoftenconcentratedinasmallstoragearea.(3)localityprincipleofinstructionexecutionsequence.Instructionsequenceexecutionismorelikelythantransferexecution.Inathreestagememorysystem,thestoredinformationmustsatisfythefollowingprinciples: ConsistencyprincipleThatis,thesameinformationwillbestoredinseverallevelsofmemoryatthesametime,thisinformationmustbekeptthesamevalueinseverallevelsofmemory.InclusionprincipleIntheinnerlayer(closetoCPU)inmemoryofinformationmustbeincludedinthememoryoftheouterlayers,namelyalltheinformationinthememoryisacopyoftheinnerpartoftheouterinformationstoredinmemory,thisistoensurethenormaloperationoftheprocedures,toachieveinformationsharing,improvetheutilizationrateofrequiredsystemresources.Notviceversa.10.whatisaninterface?Whatisitsmainfunction?Answer:theproblemofdataexchangewillbringintothecorrespondinglogiccomponentsbetweensynchronizationandcoordination,dataformatconversioninthehostandperipherals,theselogiccomponentsarecalledinputandoutputinterface,referredtoastheinterface.Thebasicfunctionsoftheinput/outputinterfaceare:(1)torealizedatabufferingandprovidedatabuffermechanismintheprocessofexchanginginformationbetweenhostandequipment,sothatthehostandtheperipheraldevicecanmeettheworkingspeed.(2)thedataformatconversion,forexample,whenthesignal isnotcomplicitinhostanddeviceandsignallevelconversionfunction,datatransmissionformat(serialandparallel)conversionfunction,directmemoryaccessinadditionaldemand.(3)providethestatusofperipheralsandinterfaces,provideeffectivehelpforCPUtocontrolallkindsofperipherals,andexchangethestatusinformationofhostandperipheraldevices.(4)torealizethecommunicationandcontrolbetweenthehostandtheperipheral,andrealizethedataexchangebetweenthehostandthedevice.Thirdchapters3.brieflydescribethecommonfeaturesofmachinelanguageandassemblylanguage.Assemblylanguagehasanessentiallyinstructionsystemcorrespondingtomachinelanguage.Inmostcases,aassemblerdirectivedirectlycorrespondstoamachineinstruction,andafewassemblyinstructionscorrespondtoseveralmachineinstructions,sotheessenceofassemblylanguageisthesameasmachinelanguage.Aswiththemachineinstructions,assemblyinstructionsdirectlytothecomputerhardwareoperation,requiretheprogrammerhasprofoundknowledgeofcomputerscience;eachinstructioncanonlyachieveaveryfineoperation(e.g.,mobileincrement),thesourceprogramisgenerallymorecomplex,tediousanderrorprone.9.brieflydescribethefunctionsofsemanticprocessing. Answer:thesemanticprocessinginthecompilationprocessimplementstwofunctions:(1)toexaminethestaticsemanticsofeachgrammaticalstructure,thatis,toverifywhetherasyntaxstructureislegitimateisreallymeaningful,andsometimesrefertothisworkasstaticsemanticanalysisorstaticreview.(2)ifthestaticsemanticsiscorrect,thesemanticprocessingmustexecutetherealtranslation,orgenerateanintermediaterepresentationoftheprogram(intermediatecode),orgeneratetheactualtargetcode.Whatisthetaskofthe11.targetcodegenerationphase?Answer:thetaskofthetargetcodegenerationphaseistotransformtheintermediatecodeintotheabsoluteinstructioncodeorrelocatableinstructioncodeorassemblyinstructioncodeonaparticularmachine.Thisisthefinalstageofcompilation,Itisrelatedtothestructureofthehardwaresystemandinstructionmeaning,thisphaseofworkisverycomplex,involvingtheuseofstoragespaceallocation,functionalcomponentsofhardwaresystemofmachineinstructions,varioustypesofdatavariablesandschedulingregisterandbackupregisteretc..Fourthchapters Whatarethecharacteristicsofprogramminglanguageusingtop-downprogrammingin3.structuredprogramminglanguage?Answer:usingstructuredprogramminglanguageusingtop-downmethodofprogrammingischaracterizedby:(1)thestructureoftheproblemdecomposedintosubproblemsmustcorrespondtooneofthe3basicprogramstructures.(2)thedivisionoftheproblemdeterminesthestructureoftheprogram.Ontheonehand,thesubproblemdeterminestheleveloftheprogramwhichisastructureof3basicstructures;ontheotherhand,aproblemthathowtodivideintosubproblemsisflexible,notonlyadecompositionmethod.Thequalityofthedesigndependsonthequalityofthedecomposition,andalsodeterminesthedifferentstructuresoftheprogram.(3)theboundaryoftheproblemshouldbeclearanddefinite.Onlyinthiswaycanwesolvetheseproblemsaccurately,otherwise,theywillbeambiguousandcannotstart.4.brieflydescribethedifferencebetweenobjectorientedandstructuredprogramming.Answer:objectorientedisanewmethodandnewideawhichisessentiallydifferentfromthetraditionalstructuredmethod.Itabsorbsalltheadvantagesofthestructureoftheprogramdesign,butalsoconsidertherelationshipbetweentherealworldandcomputer,thinksthattherealworldiscomposedofaseriesofrelatedtoeachotherandcancommunicatewitheachotherentities,thisentityistheobjectinobject-oriented method,eachobjecthasitsownnaturalattributesandbehaviorcharacteristics,andaclassofsimilartothecommonobjectisabstractdescription,objectorientedmethodinthecoreoftheclass.5.whatisadatastructure?Whatarethephysicalstructuresofdata?Answer:datastructurereferstothecollectionoftherelationshipsamongdataelements,includingthelogicalstructure,physicalstructureanddataoperationofdata.Therearefourkindsofphysicalstructureofdata,theyaresequentialstructure,linkedliststructure,indexstructureandhashstructure.(1)sequencestructure:allelementsarestoredinacontinuousstorageunit,logicalstorageadjacentelementsinthephysicallocationoftheadjacentstorageunit,thestoragerepresentationcalledsequentialstoragestructure.(2)liststructure:thelogicaladjacentelementdoesnotrequireitsphysicalpositionadjacent,thelogicalrelationshipbetweenelementsisexpressedbytheattachedpointerdomain,thusthestoragerepresentationiscalledthechainstoragestructure.(3)indexstructure:eachdatastructurecreatesanindextable,eachdataelementoccupiesoneofthetables,eachtableitemusuallycontainskeywordsandaddresspointers.Thekeywordisadataitemthatuniquelyidentifiesadataelement. (4)hashstructure:byconstructingthecorrespondinghashfunction,thevalueofthehashfunctionisusedtodeterminetheaddressstoredbytheelement.Fifthchapters1.whatisthealgorithm,whatarethecharacteristicsofthealgorithm?Answer:"Algorithm"isanorderedsetofexplicitandexecutedstepsthatterminateandproduceresultsinafiniteamountoftime".Thecharacteristicsofthealgorithmare:(1)finiteproperty(termination):analgorithmmustbeexecutedwithinafinitenumberofstepsandwithinareasonablefinitetime.(2)certainty:eachoperationstepinthealgorithmmusthaveadefinitemeaning,andnotwosenseisallowed.(3)validity(enforceability):theoperationstepsdescribedinthealgorithmareexecutable,andthefinalresultscanbeobtained.(4)inputandoutput:analgorithmshouldhavezeroormoreinputdataand1ormoreoutputdata.2.whatisthealgorithm'stimecomplexityandspacecomplexity,howtoexpress? Answer:timecomplexityisafunctionrelatedtotheproblemsizeandalgorithminput,whichrepresentsthetimeittakesforthealgorithmtorun.Remember,T(n),wherenrepresentsthesizeoftheproblem.Thespacecomplexityofthealgorithm(Spacecomplexity)isusedtomeasurethespatialcomplexityofthealgorithm,thatis,thesizeofthespaceoccupiedbytheprogramexecutingthealgorithminthecomputer.Inbrief,thespacecomplexityisalsoafunctionrelatedtotheproblemsizeandalgorithminput.Remember,S(n),wherenrepresentsthesizeoftheproblem.Thetimecomplexityandspacecomplexityarealsointroduced.Thesymbol"O"isintroducedtorepresenttheorderofmagnitudebetweenT(n),S(n)andtheproblemsizen.3.representtheprocessoflanguageprocessingbygraphicmethod.Answer:theprocessoflanguageprocessingisshowninthepicture:Sixthchapters1.abriefdescriptionofacomponentofDBMS.Answer:DBMSisusuallycomposedoffourparts,anditisalsothefunctionofDBMS:(1)datadefinitionlanguageDDLanditstranslationprocessingprogram:definethedataobjectsinthedatabase. (2)datamanipulationlanguageDMLanditscompiler(orinterpreter)program:query,insert,delete,modifyandsoon.(3)thedatabaseoperationcontrolprogram:toachieveunifiedmanagementandcontrolofthedatabase,soastoensurethesafetyandintegrityofdata,anddataconcurrencycontrol,completethedatabaseoffaultrecoveryfunction.(4)utilityprogram:completetheestablishmentandmaintenanceofdatabase,dataformatconversionandcommunication,databasedumpandotherfunctions.3.brieflydescribetheintegrityofrelationaldatabases.Answer:intherelationalmodel,threeintegrityconstraintsaredefined:entityintegrity,referentialintegrity,anduserdefinedintegrity.Themainprovisionsofentityintegritycodesinarelationship(includingthemainattributesofall)cannotbeempty;theoutercodemustbeavalidvaluekeyinanotherrelationofthereferentialintegrityrules,orempty;userdefinedintegrityisaccordingtotheapplicationrequirementsanddatarequirementsmustmeetthesemanticrequirements.Therangeofvalueofacertainattribute.Seventhchapters3.whatissoftwareengineering?Answer:softwareengineeringisanengineeringscienceresearchmethods,large-scaleprogramdesigntoolsand management,alsoistousethesystem,standardandquantitativeapproachtothedevelopment,operationandmaintenanceofsystemengineeringsoftware.Softwareengineeringisaninterdisciplinarysubject,involvingcomputerscience,managementscience,engineeringandmathematics.Thetheoryandmethodofsoftwareengineeringtechnology,arebuiltonthebasisofcomputerscience,itistheprinciple,managementmethodforsoftwareproductionmanagement;engineeringpointofviewofcostestimating,schedulingandimplementationplan;usemathematicalmethodstoestablishsoftwarereliabilitymodelandanalysisofvariousalgorithmsandproperties.Softwareengineeringisanengineeringdisciplinethatguidesthedevelopmentandmaintenanceofcomputersoftware.Ninthchapters1.whatiscalledinformation,data,signals?Answer:information(Information)istherepresentationoftheattributesandinterrelatedcharacteristicsofobjectivethings.Itreflectstheexistenceformandmovementstateofobjectivethings.Theinformationinthecomputerisacombinationofletters,numbers,symbols,andthecarrieroftheinformationcanbewritten,sound,graphics,imagesandsoon.Data(Data)isthedigitalformofinformationortheformofdigitalinformation.Signal(Signal)isthetransmissionmediumthatcarries information.Inthecommunicationsystem,itiscommonlyusedtodescribetheelectricalsignals,opticalsignals,carriersignals,pulsesignals,modulationsignalsandsoon.Fourteenthchapters3.whatarethemethodsofknowledgerepresentation?Answer:knowledgerepresentationisadescriptionofknowledge,inartificialintelligence,mainlyreferstoadatastructureapplicabletothecomputer.Inartificialintelligence,knowledgerepresentationmethodsarecommonlyused:firstorderpredicatelogicrepresentation,generativerepresentation,framerepresentation,semanticnetworkrepresentation,processrepresentation,scriptrepresentationmethod,Petrinetworkmethodandsoonobjectorientedrepresentation.4.whataretheclassicalreasoningtechniques?Answer:reasoningisthemainwayofthinkingforhumanproblemsolving,anditstaskistouseknowledge,soitiscloselyrelatedtotherepresentationofknowledge.Classicalreasoningmainlyincludesdeterministicreasoning,includingreductionreasoning,digestiondeductivereasoningandruledeductionreasoning.Theyarebasedontheclassicallogic,andusethedefiniteknowledgetocarryouttheexactreasoning,andtheyarealsoakindofmonotonicreasoning.