电政大三下-包-系统分析与设计chap10run time architecture

Chapter10DescribetheRun-timeContextintheRun-timeDescribetheRun-timeArchitectureObjectives:DescribetheRun-timeDefinethepurposeoftheDescribetheRun-timeArchitectureactivityandwheninthelifecycleitisDemonstratehowtomodelprocessesandExplainhowtomodelwhatclassesandsubsystemsaremappedtoprocessesandthreadsDefinetherationaleandconsiderationsthatsupportarchitecturaldecisionsChapter10DescribetheRun-timeContextintheRun-timeDescribetheRun-timeArchitectureDescribetheRun-timeArchitectureinDescribetheRun-timeArchitectureKeyConcepts:TheProcessTheProcessViewisan“architecturallysignificant”sliceofprocessesandthreadsoftheDesignWhatIsExampleofconcurrencyat ParallelroadsrequirelittleTwo-wayroadsrequiresomecoordinationforsafeinteractionIntersectionsrequireWhyAreWeInterestedinSoftwaremightneedtorespondtoseeminglyrandomexternallygeneratedeventsPerformingtasksinparallelcanimproveperformanceifmultipleCPUsareavailable–Example:StartupofaControlofthesystemcanenhancedthroughTosupportconcurrency,asystemmustprovideformultiplethreadsCommonconcurrencyMultipleCPUsexecuteTheoperatingsystemssimulateconcurrencyonaCPUbyinterleavingtheexecutionofdifferentApplication-basedtheapplicationsoftwaretakesresponsibilityswitchingbetweendifferentbranchescodeatappropriateChapter10DescribetheRun-timeContextintheRun-timeDescribetheRun-timeArchitectureDescribetheRun-timeArchitectureyzeconcurrencyIdentifyprocessesandIdentifyprocessMapprocessesontotheDistributemodelelementsamongConcurrencyConcurrencyrequirementsaredrivenThedegreetowhichthesystemmustbeThedegreetowhichthesystemiseventThecomputationintensityofkeyThedegreeofparallelexecutionsupportedbyConcurrencyrequirementsarerankedtermsofimportanceto Example:ConcurrencyIntheCourseRegistrationSystem,theconcurrencyrequirementscomefromtherequirementsandtheMultipleusersmustbeabletoperformtheirworkIfacourse esfullwhileastudentisbuildingscheduleincludingthatoffering,thestudentmustbeRisk-basedprototypeshavefoundthatthelegacycoursecatalogdatabasecannotmeetourperformanceneedswithoutsome creativeuseofmid-tierprocessingpowerDescribetheRun-timeArchitectureyzeconcurrencyIdentifyprocessesandIdentifyprocessMapprocessesontotheDistributemodelelementsamongKeyConcepts:ProcessandProcess:ProvidesheavyweightflowIsstand-–CanbedividedintoindividualThread:ProvideslightweightflowofRunsinthecontextofanenclosingIdentifyingProcessesandForeachseparateflowofcontrolneededbythesystem,aprocessorSeparatethreadsofcontrolmightbeneededUtilizemultipleCPUsand/orIncreaseCPUPrioritizeAchievescalability(loadSeparatetheconcernsamongsoftwareImprovementofsystemSupportmajorModelingProcessescanbemodeledActiveclasses(ClassDiagrams)andObjects(InteractionComponents(ComponentDiagrams)Stereotypes:<<process>>ProcessrelationshipscanbemodeledasThiscoursewillmodelprocessesandthreadsusingClassDiagrams.Example:ModelingProcesses:ClassExample:ModelingProcesses:ComponentDescribetheRun-timeArchitectureyzeconcurrencyIdentifyprocessesandIdentifyprocessMapprocessesontotheDistributemodelelementsamongCreatingandDestroyingProcessesandProcesscreationtakesplacewhentheapplicationProcessdestructiontakesplacewhentheapplicationendsNewprocessesaretypicallycreatedfromtheinitialprocessthatwascreatedwhentheapplicationwas–EachprocessmustbeindividuallyNote:TheCourseRegistrationSystemutilizesamulti-processarchitectureExample:CreateProcessesandCreationofthreadsduringapplicationDescribetheRun-timeArchitectureyzeconcurrencyIdentifyprocessesandIdentifyprocessMapprocessesontotheDistributemodelelementsamong ProcessesontotheProcessesandthreadsmustbemappedontoimplementationProcessPerformanceSystemprocessandthreadExistingthreadsandIPC电路资源resourceDescribetheRun-timeArchitectureyzeconcurrencyIdentifyprocessesandIdentifyprocessMapprocessesontotheDistributemodelelementsamongDesignElementInstancesofagivenclassorsubsystemexecutewithinatleastone–TheymayexecuteinseveralDesignElements-to-ProcessesBasedPerformanceandconcurrencyDistributionrequirementsandsupportforparallel–RedundancyandavailabilityClass/subsystemcharacteristicstoAutonomy(自治在一个事务中如，在一个DELETE触发器中进行一个统计,统计用户执(COMMIT),都必须 Subordination（从属在同一张数据表数据持久 （TheUnitedStatesNationalInstituteofStandards部分持久数据是一种仅允许 版本更新的持久数结构完全持久数据是一 其数据的所有版本并允许对些版本更新的持久数据结数据持久另一方面，在持久数据实现中，对系统中断或故障以（rollbac）中完全持久数据实现非常少见。完全持久数据实现的少数例有：日志记录文件系统、VMS文件系统（如VAX和/6）以及并发版本控制系统（CVS）DesignElements-to-ProcessesTwoStrategies(usedInside-–Groupelementsthatcloselycooperateandmustexecuteinsamethreadof–Separateelementsthatdonot–RepeatuntilyoureachtheminimumnumberofprocessesthatprovidetherequireddistributionandeffectiveresourceOutside-DefineaseparatethreadofcontrolforeachexternalDefineaseparateserverthreadofcontrolforeachReducenumberofthreadstowhatcanbeModelingthe ofElementstoClassActiveclassesasCompositionrelationshipsfromprocessestoCompositionrelationshipsfromprocessestoProcessProcessrelationshipsmustsupportdesignExample:RegisterforCourseExample:RegisterforCourseProcessesCheckpoints:DescribetheRun-timeWhatisthepurposeoftheDescribeConcurrencyWhatisaprocess?WhatisaDescribesomeoftheconsiderationswhenidentifyingDescribethetwostrategiesformap classesandsubsystemstoprocesses.HowdoyoumodeltheProcessViewWhatmodelingelementsanddiagramsareReview:DescribetheRun-timeWhatisthepurposeoftheDescribetheRun-timeArchitectureactivity?Whatisaprocess?WhatisaDescribesomeoftheconsiderationswhenidentifyingDescribethetwostrategiesfor classessubsystemstoHowdoyoumodeltheProcessWhatmodelingelementsanddiagramsareChapter10DescribetheRun-timeContexttheRun-timeDescribetheRun-timeArchitectureExercise:DescribetheRun-timeGiventheDesi