(9)Unit 4《信息管理与信息系统专业英语》SDLC1

信息管理与信息系统专业英语Unit2PMandSDLC-PartII(SDLC),PartII-SDLC,Learningoutlines:DoadetailedanalysisofthesystemHowtodesignthesystemHowtoacquire(gain)/developthesystem,PartIISDLC-Doadetailedanalysisofthesystem,Theobjectivesofsystemanalysis,are:togatherdatatoanalyzethedata,towriteareport.,PartIISDLC-Doadetailedanalysisofthesystem,Whatisthedefinitionofsystemanalysis?Systemanalysisdescribeswhatasystemisreadydoingandwhatitshoulddotomeettheneedsofusers.,PartIISDLC-Doadetailedanalysisofthesystem,Ingeneral,SAinvolvesadetailedstudyof:Theinformationneedsoftheorganizationandusers.Theactivities,resources,andproductsoranypresent(existing)informationsystem.Theinformationsystemscapabilities(能力)requiredtomeettheestablishedinformationneedsanduserneeds.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Bywrittendocuments。-Agreatdeal(大量）ofwhatyouneedisprobablyavailableintheformofwrittendocuments:report，forms（表格）,manuals(abookgivinginformationabouthowtodosthesp.howtouseamachine),memos(便签，备忘录),businessplans,policystatements（政策声明）,andsoon.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Onedocumentofparticularvalueistheorganizationchart(SeeFig.2.1).Anorganizationchartshowslevels(?)ofmanagementandformallines(?)ofauthority.插入51页的图。,层面,体系,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Bywrittendocuments。Interviews,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Interviews-interviewwithmanagers,workers,clients,suppliers,andcompetitorswillalsogiveyouinsights.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Interviewsincludestwotypes:2.1.Structuredinterviews2.2.unstructuredinterviews,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Interviewsincludestwotypes:2.1.Structuredinterviewsincludes:-onlyquestionsyouhaveplannedandwrittenoutinadvance.Bystickingwiththisscript（脚本，原本，底稿）,youcanaskanumberofpeopleidentical（same）questionsandcomparetheiranswers.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Interviewsincludestwotypes:2.2.unstructuredinterviews-questionspreparedinadvance,butyoucanvaryfrom(不同于)thelineofquestionsandpursue(carryon)othersubjectsifitseemsproductive(富有成效).Again,JAD(联合应用开发)（page38）sessionmaybeused.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Bywrittendocuments。InterviewsQuestionnaires,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Questionnaires-questionnairesareusefulforgettinginformationforalargegroupsofpeoplewhenyoucantgetaroundtointerviewingeveryone.Questionnairesmayalsoyield(产生。效果)moreinformationifrespondentscanbeanonymous（匿名的）.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Questionnaires-Inaddition,thistoolisconvenient（方便的）,isexpensive,andyieldsalotofdata.However,peoplemaynotreturntheirforms,resultscanbeambiguous(含糊不清),andwithanonymous（匿名的）questionnaire,youhavenoopportunitytofollowup（弄明白）.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Bywrittendocuments。InterviewsQuestionnairesObservation,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Observation-Nodoubtyouvesatinacoffeeshoporonaparkbenchandjustdone”peoplewatching”.Thiscanbeatoolforanalysistoo,throughobservationyoucanseehowpeopleinteractwithoneanother.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Observation-Observationcanbeparticipantandnonparticipant.Ifyouarenonparticipantobserver,andpeopleknewtheyarebeingwatched,theymayfalsify(假装)theirbehaviorinsomeway.Ifyouareaparticipantobserver,youmaygainmoreinsightsbyexperiencingtheconflictandresponsibilitiesofthepeopleyouareworkingwith.,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Bywrittendocuments。InterviewsQuestionnairesObservationsampling,PartIISDLC-Doadetailedanalysisofthesystem,HowtoGatherdata?Sampling-Ifyourdata-gatheringphasesinvolvesalargenumberofpeopleorevents,itmaysimplifythingstostudyjustasasample.Thatis,youcandoasamplingoftheworkof5peopleinsteadof100,or20instances(example,case)ofaparticulartransactioninsteadof500.,PartII-SDLC,AnalyzethedataOncethedataisgathered,youneedtocometogripswith(运用)itandanalyzeit.Manyanalyticaltools,ormodellingtools,areavailable.Canyoulistoneortwotools？,PartIISDLC-Doadetailedanalysisofthesystem,ToolsforanalyzingthedataCASETools,PartIISDLC-Doadetailedanalysisofthesystem,ToolsforanalyzingthedataCASETools-CASE(Computer-aidedSoftwareEngineering)tools,softwareprogramsthatautomatemanyactivitiesintheSDLC,arealsousedtoanalyzevariousaspectsofasystem.,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataCASEToolsDataFlowdiagrams（数据流图）,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataDataFlowdiagrams-DFD,alsocalledaprocessmodel,graphically（用图表表示）showstheflowofdatathroughasystemthatistheessentialprocessofasystemalongwithinputs,outputs,andfiles.看53页的图片,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataCASEToolsDataFlowDiagramsSystemFlowcharts,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataSystemFlowcharts-calledthesystemflowdiagramaswell.Asystemflowchartdiagramsthemajorinputs,outputs,andprocessofasystem.InsomecasessystemsflowchartcanbeusedinplaceofaDFD;inothercases,itisausefulsupplement.,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataCASEToolsDataFlowdiagramsSystemFlowchartsConnectivitydiagrams(关联图),PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataConnectivitydiagrams-Aconnectivitydiagramisusedtomanynetworkconnectionsofpeople,data,andactivitiesatvariouslocation.Connectivitydiagramsareconcernedwithcommunicationsnetworks,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataCASEToolsDataFlowdiagramsSystemFlowchartsConnectivitydiagramsGridcharts(栅格图),PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataGridcharts-Agridchartshowtherelationshipbetweendataoninputdocumentsanddataonoutputdocuments.(seepage53Table2.2),PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataCASEToolsDataFlowdiagramsSystemFlowchartsConnectivitydiagramsGridchartsDecisiontable,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataDecisiontable-Adecisiontableshowsthedecisionrulesthatapplywhencertainconditionsoccurandwhatactionstotake.Thatis,adecisiontableprovidesamodelofasimple,structureddecision-makingprocess.Itshowswhichconditionsmusttakeplaceinorderforparticularactiontooccur(seepage55Table2.3)(*),PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataCASEToolsDataFlowdiagramsSystemFlowchartsConnectivitydiagramsGridchartsDecisiontableObject-orientedanalysis,PartIISDLC-Doadetailedanalysisofthesystem,AnalyzethedataObject-orientedanalysis(OOA):-Forthepast30years,mostsystemsdevelopmentstrategieshavedeliberately(周密地)givenseparateconsiderationtodataandtoprocesses.Insteaddataandprocessesthatactonthedataarecombined,orencapsulated(压缩)intothingscalledobjects”,PartIISDLC-Designthesystem,Designthesystemincludesfourareas:Whatshouldhavebeencreated?(seepage57)DoapreliminarydesignDoadetaileddesignFinally,Writeareport.,PartIISDLC-Designthesystem,DoapreliminarydesignApreliminarydesigndescribesthegeneralfunctionalcapabilitiesofaproposedinformationsystem.Usuallyseveralalternativesystems(calledcandidates)areconsidered,and,andthebenefitsofeachareevaluated.(page58).,PartIISDLC-Designthesystem,DoapreliminarydesignTwotools,whichareusedtodothepreliminarydesign,willbementionedhere.Theyare:Casetools:.CASEtoolsaresoftwareprogramsthatautomatevariousactivitiesoftheSDLC.thisscreenisfromoneoftheirbankingsystemtools.ItshowsamodelforanATMtransaction.(page58).,PartIISDLC-Designthesystem,DoapreliminarydesignTwotools,whichareusedtodothepreliminarydesign,willbementionedhere.Theyare:ExamplesofareExcelerator,Iconix,.Rationalrose,andPowerBuilder.so-calledfront-endCASEtools,orupper-CASEtools,so-calledback-endCASEtools,orlower-CASEtools.,PartIISDLC-Designthesystem,DoapreliminarydesignProjectmanagementsoftware:-.projectmanagementsoftwareoftenusesGanttChartsandPERTcharts.AGanttchartslinesandbarstoindicatethedurationofaseriesoftasks.Apertchartshowsnotonlytimingbutalsorelationships(dependencies)amongthetasksofaproject.Someofwhichmustbecompletedbeforeotherscanbegins.(page60).(seeGanttchartsfigure),PartIISDLC-Designthesystem,DoapreliminarydesignCasetoolscanbeusedformanyfunctions.Amongthemarethese:Diagramming:.ofsystemcomponentandmodels（59）,PartIISDLC-Designthesystem,DoapreliminarydesignCasetoolscanbeusedformanyfunctions.Amongthemarethese:Prototyping:Prototypingreferstousingworkstations,.tobuildworkingmodels(experimentalversions)of.sotheycanquicklytestedandevaluated.,PartIISDLC-Designthesystem,DoapreliminarydesignCasetoolscanbeusedformanyfunctions.Amongthemarethese:Prototyping:AprototypeallowuserstofindoutimmediatelyhowachangeinthesystemmightbenefitthemThenprototypecanberefinedandincludedinthemenucanthenberedesigned,.userinterface(page59).,PartIISDLC-Designthesystem,DoapreliminarydesignCasetoolscanbeusedformanyfunctions.Amongthemarethese:Reporting:reportcanbeextractedfromtheCASEtoolsdatabaseManagingquality:CASEtoolscan.forconsistency(一致性）,completeness(完整性),andconformance(符合性)torulesSupportingdecisions:some.helpsystemanalystsestimateandanalyzefeasibility.,PartIISDLC-Designthesystem,DoapreliminarydesignCasetoolscanbeusedformanyfunctions.Amongthemarethese:Organizingdocumentation:CASEtoolscanassemble,organize,andGeneratingcode:orsignificantportionsof.testing:.(page60),PartIISDLC-Designthesystem,DoadetaildesignAdetaildesigndescribeshowaproposedinformationsystemwilldeliverthegeneralcapabilitiesdescribedinthepreliminarydesign.Thepartsaretheseinthisorder:,PartIISDLC-Designthesystem,DoadetaildesignOutputrequirements-Thefirstthingtodetermineiswhatyouwantthesystemtoproduce.whetherhardcopy(硬拷贝)and/orsoftcopy()anddesignstheappearance(outsidequalitiesofapersonorthing)orformatoftheoutput,suchasheadings,columns,andmenus.,PartIISDLC-Designthesystem,DoadetaildesignInputrequirements-suchaskeyboardorsourcedataentry,youmustdetermineinwhatformdatawillbeinputandhowitwillbecheckedforaccuracy.Youalsoneedtofigureout(understandordiscoverbythinking)whatvolume(卷)ofdatathesystemcanbeallowedtotakein(include).,PartIISDLC-Designthesystem,DoadetaildesignStoragerequirements-usingthedatadictionaryaswhatkindofstoragedeviceswillbeused?Howwilltheyinterface(通过接口链接)withotherstoragedevicesinsiderandoutsideoftheorganization?(page61),PartIISDLC-Designthesystem,DoadetaildesignProcessing(处理)andnetworking(组网)requirements-whatkindofcomputerorcomputerswillbeusedtohandle(control/dealwith)theprocessing?Whatkindofoperatingsystemandapplicationsoftwarewillbeused?.willthecomputerorcomputersbetied(连接)toothersinanetwork?.whatkindofuserinterfacearedesigned?,PartIISDLC-Designthesystem,DoadetaildesignSystemcontrolandbackup-Finally,youneedtothinkaboutmattersofsecurity,privacy,anddataaccuracy.Youneedtopreventunauthorized（未授权的）userfrombreakingintothesystem,andsnooping(偷听)inprivatefiles.devise(toplanorinvent)auditing（审计）proceduresand.(page61),PartIISDLC-Develop/acquire(gain/obtain)thesystem,Thissectionwillcoverthesefollowingparts:WhatgeneraltasksdosystemsanalystsperforminthefourthphaseoftheSDLC?AcquiresoftwareAcquirehardwareTestthesystem,PartIISDLC-Develop/acquirethesystem,Thissectionwillcoverthesefollowingparts:WhatgeneraltasksdosystemsanalystsperforminthefourthphaseoftheSDLC?-thisphasewillinvolvesubstantial(largeenoughtosatisfactory)expendituresofmoneyandtime(page63).,PartIISDLC-Develop/acquirethesystem,Thissectionwillcoverthesefollowingparts:Acquiresoftware-Duringthedesignstage,thesystemsanalystmayhavehadtoaddresswhatiscalledthe“make-or-buy”decision;ifnot,thatdecisioncertainlycannotavoidednow.In.ratherthanwriteitfromscratch(从头做起).tohireoutsidecontractprogrammers(outsource(转包给)it).Whicheverwayyougo,thetaskcouldtakemonths.(page63),PartIISDLC-Develop/acquirethesystem,Thissectionwillcoverthefollowingparts:Acquirehardware-.youwillneedtoobtainanynewhardwarewillcostmillionsofdollars.:microcomputers,minicomputers,mainframe,monitors,modems,.Mayprefertolease(租用)ratherth