Software Development Life Cycle (SDLC).ppt

softwaredevelopmentlifecycle sdlc you vegottobeverycarefulifyoudon tknowwhereyou regoing becauseyoumightnotgetthere yogiberra capabilitymaturitymodel cmm abench markformeasuringthematurityofanorganization ssoftwareprocesscmmdefines5levelsofprocessmaturitybasedoncertainkeyprocessareas kpa cmmlevels level5 optimizing 1 processchangemanagement technologychangemanagement defectpreventionlevel4 managed 5 softwarequalitymanagement quantitativeprocessmanagementlevel3 defined 10 peerreviews intergroupcoordination softwareproductengineering integratedsoftwaremanagement trainingprogram organizationprocessdefinition organizationprocessfocus level2 repeatable 15 softwareconfigurationmanagement softwarequalityassurance softwareprojecttrackingandoversight softwareprojectplanning requirementsmanagementlevel1 initial 70 sdlcmodel aframeworkthatdescribestheactivitiesperformedateachstageofasoftwaredevelopmentproject waterfallmodel requirements definesneededinformation function behavior performanceandinterfaces design datastructures softwarearchitecture interfacerepresentations algorithmicdetails implementation sourcecode database userdocumentation testing waterfallstrengths easytounderstand easytouseprovidesstructuretoinexperiencedstaffmilestonesarewellunderstoodsetsrequirementsstabilitygoodformanagementcontrol plan staff track workswellwhenqualityismoreimportantthancostorschedule waterfalldeficiencies allrequirementsmustbeknownupfrontdeliverablescreatedforeachphaseareconsideredfrozen inhibitsflexibilitycangiveafalseimpressionofprogressdoesnotreflectproblem solvingnatureofsoftwaredevelopment iterationsofphasesintegrationisonebigbangattheendlittleopportunityforcustomertopreviewthesystem untilitmaybetoolate whentousethewaterfallmodel requirementsareverywellknownproductdefinitionisstabletechnologyisunderstoodnewversionofanexistingproductportinganexistingproducttoanewplatform highriskfornewsystemsbecauseofspecificationanddesignproblems lowriskforwell understooddevelopmentsusingfamiliartechnology v shapedsdlcmodel avariantofthewaterfallthatemphasizestheverificationandvalidationoftheproduct testingoftheproductisplannedinparallelwithacorrespondingphaseofdevelopment v shapedsteps projectandrequirementsplanning allocateresourcesproductrequirementsandspecificationanalysis completespecificationofthesoftwaresystemarchitectureorhigh leveldesign defineshowsoftwarefunctionsfulfillthedesigndetaileddesign developalgorithmsforeacharchitecturalcomponent production operationandmaintenance provideforenhancementandcorrectionssystemandacceptancetesting checktheentiresoftwaresysteminitsenvironmentintegrationandtesting checkthatmodulesinterconnectcorrectlyunittesting checkthateachmoduleactsasexpectedcoding transformalgorithmsintosoftware v shapedstrengths emphasizeplanningforverificationandvalidationoftheproductinearlystagesofproductdevelopmenteachdeliverablemustbetestableprojectmanagementcantrackprogressbymilestoneseasytouse v shapedweaknesses doesnoteasilyhandleconcurrenteventsdoesnothandleiterationsorphasesdoesnoteasilyhandledynamicchangesinrequirementsdoesnotcontainriskanalysisactivities whentousethev shapedmodel excellentchoiceforsystemsrequiringhighreliability hospitalpatientcontrolapplicationsallrequirementsareknownup frontwhenitcanbemodifiedtohandlechangingrequirementsbeyondanalysisphasesolutionandtechnologyareknown protoyping basicsteps identifybasicrequirementsincludinginputandoutputinfodetails e g security generallyignoreddevelopinitialprototypeuifirstreviewcustomers end usersreviewandgivefeedbackreviseandenhancetheprototype specsnegotiationaboutscopeofcontractmaybenecessary dimensionsofprototyping horizontalprototypebroadviewofentiresystem sub systemfocusisonuserinteractionmorethanlow levelsystemfunctionality e g databsaeaccess usefulfor confirmationofuirequirementsandsystemscopedemonstrationversionofthesystemtoobtainbuy infrombusiness customersdeveloppreliminaryestimatesofdevelopmenttime cost effort dimensionsofprototyping verticalprototypemorecompleteelaborationofasinglesub systemorfunctionusefulfor obtainingdetailedrequirementsforagivenfunctionrefiningdatabasedesignobtaininginfoonsysteminterfaceneedsclarifyingcomplexrequirementsbydrillingdowntoactualsystemfunctionality typesofprototyping throwaway rapid close endedprototypingcreationofamodelthatwillbediscardedratherthanbecomingpartofthefinaldeliveredsoftwareafterpreliminaryrequirementsgathering usedtovisuallyshowtheuserswhattheirrequirementsmaylooklikewhenimplementedfocusisonquicklydevelopingthemodelnotongoodprogrammingpracticescanwizardofozthings fidelityofprotype low fidelitypaper pencilmimicsthefunctionality butdoesnotlooklikeit fidelityofprotype mediumtohigh fidelityguibuilder clickdummy prototype lookslikethesystem butdoesnotprovidethefunctionalityorprovidefunctionality buthaveitbegeneralandnotlinkedtospecificdata throwawayprototypingsteps writepreliminaryrequirementsdesigntheprototypeuserexperiences usestheprototype specifiesnewrequirementsrepeatifnecessarywritethefinalrequirementsdeveloptherealproducts evolutionaryprototyping akabreadboardprototypinggoalistobuildaveryrobustprototypeinastructuredmannerandconstantlyrefineittheevolutionaryprototypeformstheheartofthenewsystemandisaddedtoandrefinedallowthedevelopmentteamtoaddfeaturesormakechangesthatwerenotconceivedintheinitialrequirements evolutionaryprototypingmodel developersbuildaprototypeduringtherequirementsphaseprototypeisevaluatedbyendusersusersgivecorrectivefeedbackdevelopersfurtherrefinetheprototypewhentheuserissatisfied theprototypecodeisbroughtuptothestandardsneededforafinalproduct epsteps apreliminaryprojectplanisdevelopedanpartialhigh levelpapermodeliscreatedthemodelissourceforapartialrequirementsspecificationaprototypeisbuiltwithbasicandcriticalattributesthedesignerbuildsthedatabaseuserinterfacealgorithmicfunctionsthedesignerdemonstratestheprototype theuserevaluatesforproblemsandsuggestsimprovements thisloopcontinuesuntiltheuserissatisfied epstrengths customerscan see thesystemrequirementsastheyarebeinggathereddeveloperslearnfromcustomersamoreaccurateendproductunexpectedrequirementsaccommodatedallowsforflexibledesignanddevelopmentsteady visiblesignsofprogressproducedinteractionwiththeprototypestimulatesawarenessofadditionalneededfunctionality incrementalprototyping finalproductbuiltasseparateprototypesattheend theprototypesaremergedintoafinaldesign extremeprototyping oftenusedforwebapplicationsdevelopmentbrokendowninto3phases eachbasedonthepreceding1staticprototypeconsistingofhtmlpagesscreenareprogrammedandfullyfunctionalusingasimulatedserviceslayerfullyfunctionaluiisdevelopedwithlittleregardtotheservices otherthantheircontractservicesareimplemented prototypingadvantages reducedtimeandcostcanimprovethequalityofrequirementsandspecificationsprovidedtodevelopersearlydeterminationofwhattheuserreallywantscanresultinfasterandlessexpensivesoftwareimproved increaseduserinvolvementusercanseeandinteractwiththeprototype allowingthemtoprovidebetter morecompletefeedbackandspecsmisunderstandings miscommunicationsrevealedfinalproductmorelikelytosatisfytheirdesiredlook feel performance disadvantagesofprototyping1 insufficientanalysisfocusonlimitedprototypecandistractdevelopersfromanalyzingcompleteprojectmayoverlookbettersolutionsconversionoflimitedprototypesintopoorlyengineeredfinalprojectsthatarehardtomaintainlimitedfunctionalitymaynotscalewellifusedasthebasisofafinaldeliverablemaynotbenoticedifdeveloperstoofocusedonbuildingprototypeasamodel disadvantagesofprototyping2 userconfusionofprototypeandfinishedsystemuserscanthinkthataprototype intendedtobethrownaway isactuallyafinalsystemthatneedstobepolishedunawareofthescopeofprogrammingneededtogiveprototyperobustfunctionalityuserscanbecomeattachedtofeaturesincludedinprototypeforconsiderationandthenremovedfromfinalspecification disadvantagesofprototyping3 developerattachmenttoprototypeifspendagreatdealoftime efforttoproduce maybecomeattachedmighttrytoattempttoconvertalimitedprototypeintoafinalsystembadiftheprototypedoesnothaveanappropriateunderlyingarchitecture disadvantagesofprototyping4 excessivedevelopmenttimeoftheprototypeprototypingsupposedtobedonequicklyifdeveloperslosesightofthis cantrytobuildaprototypethatistoocomplexforthrowawayprototypes thebenefitsrealizedfromtheprototype preciserequirements maynotoffsetthetimespentindevelopingtheprototype expectedproductivityreduceduserscanbestuckindebatesoverprototypedetailsandholdupdevelopmentprocess disadvantagesofprototyping5 expenseofimplementingprototypingstartupcostsofprototypingmaybehighexpensivetochangedevelopmentmethodologiesinplace re training re tooling slowdevelopmentifpropertrainingnotinplacehighexpectationsforproductivityunrealisticifinsufficientrecognitionofthelearningcurvelowerproductivitycanresultifoverlooktheneedtodevelopcorporateandprojectspecificunderlyingstructuretosupportthetechnology bestusesofprototyping mostbeneficialforsystemsthatwillhavemanyinteractionswithendusersthegreatertheinteractionbetweenthecomputerandtheuser thegreaterthebenefitofbuildingaquicksystemfortheusertoplaywithespeciallygoodfordesigninggoodhuman computerinterfaces spiralsdlcmodel addsriskanalysis and4glradprototypingtothewaterfallmodeleachcycleinvolvesthesamesequenceofstepsasthewaterfallprocessmodel spiralquadrant determineobjectives alternativesandconstraints objectives functionality performance hardware softwareinterface criticalsuccessfactors etc alternatives build reuse buy sub contract etc constraints cost schedule interface etc spiralquadrant evaluatealternatives identifyandresolverisks studyalternativesrelativetoobjectivesandconstraintsidentifyrisks lackofexperience newtechnology tightschedules poorprocess etc resolverisks evaluateifmoneycouldbelostbycontinuingsystemdevelopment spiralquadrant developnext levelproduct typicalactivites createadesignreviewdesigndevelopcodeinspectcodetestproduct spiralquadrant plannextphase typicalactivitiesdevelopprojectplandevelopconfigurationmanagementplandevelopatestplandevelopaninstallationplan spiralmodelstrengths providesearlyindicationofinsurmountablerisks withoutmuchcostusersseethesystemearlybecauseofrapidprototypingtoolscriticalhigh riskfunctionsaredevelopedfirstthedesigndoesnothavetobeperfectuserscanbecloselytiedtoalllifecyclestepsearlyandfrequentfeedbackfromuserscumulativecostsassessedfrequently spiralmodelweaknesses timespentforevaluatingriskstoolargeforsmallorlow riskprojectstimespentplanning resettingobjectives doingriskanalysisandprototypingmaybeexcessivethemodeliscomplexriskassessmentexpertiseisrequiredspiralmaycontinueindefinitelydevelopersmustbereassignedduringnon developmentphaseactivitiesmaybehardtodefineobjective verifiablemilestonesthatindicatereadinesstoproceedthroughthenextiteration whentousespiralmodel whencreationofaprototypeisappropriatewhencostsandriskevaluationisimportantformediumtohigh riskprojectslong termprojectcommitmentunwisebecauseofpotentialchangestoeconomicprioritiesusersareunsureoftheirneedsrequirementsarecomplexnewproductlinesignificantchangesareexpected researchandexploration roleplayinggameforse s housekeeping individualassignment postmortem peerreviewfinalpresentations demosjuly26 28 25minutesper 8minutepresentation 10minutedemo 7minutesquestionscourseevaluationsthisthursday 4 05pm theriseandfallofwaterfall agilesoftwaredevelopmentlifecycles agilesdlc s speeduporbypassoneormorelifecyclephasesusuallylessformalandreducedscopeusedfortime criticalapplicationsusedinorganizationsthatemploydisciplinedmethods someagilemethods rapidapplicationdevelopment rad incrementalsdlcscrumextremeprogramming xp adaptivesoftwaredevelopment asd featuredrivendevelopment fdd crystalcleardynamicsoftwaredevelopmentmethod dsdm rationalunifyprocess rup agilevswaterfallpropaganda rapidapplicationdevelopment rad model rapidapplicationmodel rad requirementsplanningphase aworkshoputilizingstructureddiscussionofbusinessproblems userdescriptionphase automatedtoolscaptureinformationfromusersconstructionphase productivitytools suchascodegenerators screengenerators etc insideatime box dountildone cutoverphase installationofthesystem useracceptancetestingandusertraining requirementsplanningphase combineselementsofthesystemplanningandsystemsanalysisphasesofthesystemdevelopmentlifecycle sdlc users managers anditstaffmembersdiscussandagreeonbusinessneeds projectscope constraints andsystemrequirements itendswhentheteamagreesonthekeyissuesandobtainsmanagementauthorizationtocontinue userdesignphase usersinteractwithsystemsanalystsanddevelopmodelsandprototypesthatrepresentallsystemprocesses inputs andoutputs typicallyuseacombinationofjointapplicationdevelopment jad techniquesandcasetoolstotranslateuserneedsintoworkingmodels acontinuousinteractiveprocessthatallowsuserstounderstand modify andeventuallyapproveaworkingmodelofthesystemthatmeetstheirneeds jadtechniques http en wikipedia org wiki joint application designcasetoolshttp en wikipedia org wiki computer aided software engineering constructionphase focusesonprogramandapplicationdevelopmenttasksimilartothesdlc however userscontinuetoparticipateandcanstillsuggestchangesorimprovementsasactualscreensorreportsaredeveloped itstasksareprogrammingandapplicationdevelopment coding unit integration andsystemtesting cutoverphase resemblesthefinaltasksinthesdlcimplementationphase comparedwithtraditionalmethods theentireprocessiscompressed asaresult thenewsystemisbuilt delivered andplacedinoperationmuchsooner tasksaredataconversion full scaletesting systemchangeover usertraining radstrengths reducedcycletimeandimprovedproductivitywithfewerpeoplemeanslowercoststime boxapproachmitigatescostandscheduleriskcustomerinvolvedthroughoutthecompletecycleminimizesriskofnotachievingcustomersatisfactionandbusinessneedsfocusmovesfromdocumentationtocode wysiwyg usesmodelingconceptstocaptureinformationaboutbusiness data andprocesses radweaknesses accelerateddevelopmentprocessmustgivequickresponsestotheuserriskofneverachievingclosurehardtousewithlegacysystemsrequiresasystemthatcanbemodularizeddevelopersandcustomersmustbecommittedtorapid fireactivitiesinanabbreviatedtimeframe whentouserad reasonablywell knownrequirementsuserinvolvedthroughoutthelifecycleprojectcanbetime boxedfunctionalitydeliveredinincrementshighperformancenotrequiredlowtechnicalriskssystemcanbemodularized incrementalsdlcmodel constructapartialimplementationofatotalsystemthenslowlyaddincreasedfunctionalitytheincrementalmodelprioritizesrequirementsofthesystemandthenimplementsthemingroups eachsubsequentreleaseofthesystemaddsfunctiontothepreviousrelease untilalldesignedfunctionalityhasbeenimplemented incrementalmodelstrengths develophigh riskormajorfunctionsfirsteachreleasedeliversanoperationalproductcustomercanrespondtoeachbuilduses divideandconquer breakdownoftaskslowersinitialdeliverycostinitialproductdeliveryisfastercustomersgetimportantfunctionalityearlyriskofchangingrequirementsisreduced incrementalmodelweaknesses requiresgoodplanninganddesignrequiresearlydefinitionofacompleteandfullyfunctionalsystemtoallowforthedefinitionofincrementswell definedmoduleinterfacesarerequired somewillbedevelopedlongbeforeothers totalcostofthecompletesystemisnotlower whentousetheincrementalmodel risk funding schedule programcomplexity orneedforearlyrealizationofbenefits mostoftherequirementsareknownup frontbutareexpectedtoevolveovertimeaneedtogetbasicfunctionalitytothemarketearlyonprojectswhichhavelengthydevelopmentschedulesonaprojectwithnewtechnology scrum scrum scrumin13seconds scrumadvantages agilescrumhelpsthecompanyinsavingtimeandmoney scrummethodologyenablesprojectswherethebusinessrequirementsdocumentationishardtoquantifytobesuccessfullydeveloped fastmoving cuttingedgedevelopmentscanbequicklycodedandtestedusingthismethod asamistakecanbeeasilyrectified scrumadvantages itisalightlycontrolledmethodwhichinsistsonfrequentupdatingoftheprogress