Software Design, Verification and Validation：软件设计，验证和确认.ppt

SoftwareDesign,VerificationandValidationElementsofaCodeIntegrityManagementSystemforReal-,.******@ProblemDefinitionTypicalScenario:1SeniorManager178–200projectreleases2releaseswithmajorProblems176releaseswithoutanymajorproblemQuestion:Howdoweanticipatethosetwo“BadReleases”eaproblemConsiderTheseStatisticsStatistic#1:Foreverythousandlinesofcodedevelopedbysoftwareengineers,therecouldbeasmanyas20to30defectsonaverageStatistic#2:In2003,DeveloperNewsreported50percentofallbugfixesareincorrectlyperformedthefirsttime,oftenintroducingnewbugsinthefixingprocessStatistic#3:Asbugsprogressthroughthedevelopmentcycle,eexponentiallymoreexpensivetofix–itisatleast30timesmorecostlytofixsoftwareinthecustomerversusduringdevelopment–SEI2001Forautomotivereleasingabugintothefieldmaypromoteaverycostlyrecallofthatvehicle(s)SoftwareDefectsSoftwaredefectsareinevitable.“…peoplewhowritesoftwarearehumanfirstandprogrammersonlysecond–Inshort,theymakemistakes,lotsofthem...” plexity?AvionicsBoeing7474MLOCTechnologyReview2002Automotive2010Premium100MLOC1995–200052%/Year2001–201035%/YearTonyScott,plexityModelsMetricsMaturityModelTMM–plexityPROBLEMHWSolution#1SWSolution#1COMPLEXITYHW/SWCo-DesignSizeErrorPronenessQualitySolution#1UsabilityReliabilityChangeProductivitySolution#plexityofSW?SizeModulelengthToolsLanguageFeaturesManagementReuseOutsourcingUnnecessaryfunctionalityEtc…Error-petenceMethodsUnnecessaryfunctionalityEtc…Itisamulti-eed?eedwillbethosethatcandevelophigh-qualitysoftwarefaster,morereliably,andmorecost-petitors.