Information SystemPowerPoint PresentationSlide 3Systems Development: the processSlide 5Slide 6Two system development approachesSDLCSystem development catalystsProjects of varying complexityWhy do IS projects fail?Successful systems developmentBugs!Software: the productSlide 15The Systems AnalystSlide 17Slide 18Guiding principlesSoftware development - The ProcessAlternatively…Alternatively (2)…Slide 23Slide 24Slide 25Slide 26Slide 27Systems AnalysisSystem designSystem ImplementationCross Life Cycle ActivitiesSlide 32Slide 33Slide 34Software Engg. Paradigms ( Process models)Waterfall ModelSoftware Engineering paradigmsPrototyping: ProblemsSlide 39Rapid Application DevelopmentRADSlide 42O-O developmentSlide 44Information System•IS: a set of related components working together in some environment to perform functions that achieve some objective.ProcessStandard operatingproceduresOrganizationalpoliciesInput OutputCustomersCompetitorsGovernmentRegulationsShippers•IS Functions–Input, Processing, Output, Storage, Controls•IS Components–People, Procedures, Data, Software, HardwareAlternative: Object-oriented view of a systemSystems Development: the process•System lifecycle: –development phase *–production phase•Systems approach–divide and conquerconversion•System Analysis–study business problem domain, existing system–identify requirements–specify characteristics of new system•System decomposition–by functions performed–in terms of objectsSystems Development: the process•System Design–evaluate alternative solutions,design a chosen solution–design document: basis for implementationSystems Development: the processTwo system development approaches•Functional Decomposition–identify major activities, break up into composite steps (structured analysis and design)–focus on verbs (what a system does)•Objects that comprise the system and how they act and relate–object structure and behavior analysis–focus on nouns (objects performing functions)SDLC•System development methodology–activities to solve a problem•A methodology uses certain techniques(used to model a system)•Model–representation of real world–used in analyzing and communicating what we understandDATA MODELS, PROCESS MODELS, OBJECT MODELS, etc.System development catalysts•User demandproblems in current system, need for enhancements, improved efficiency•Technology pushnew technology as catalysts•Strategic pullsystem to support new business strategies/ products to stay competitiveProjects of varying complexity•Upto 1000 lines–trivial, single person, few days/week•1000-10,000 lines–simple, 3/4 progr/analyst, 6-12 months–often formal analysis and design not used, but could be - leads to more maintainable system•10,000-100,000 lines–difficult, 6-12 people, 2-3 years–formal analysis and design essential–requirements/users change over time•100,000 - 1 million lines–complex. 50-100 people, 3-5 years–diverse community of users•1-10 million lines–nearly impossible•> 10 million–absurd??Why do IS projects fail?•Did not support business strategy & objectives•poor planning, project management•failure to understand user requirements –user involvement in system development•inadequate cost vs. benefit analysis–escalating costs, intangible benefits•myriad of design defects/ errors•installation of incompatible or inadequate technology•no adequate controls implemented•unstructured, un-maintainable softwareSuccessful systems development•Informal, sloppy art structured, engineered and managed approach (SDLC)•stress user involvement in system development•system planning and project management•evaluate alternate designs before committing•clean, complete and up-to-date documentation•design for growth and changeBugs!•software errors cost U.S. users $59.5 billion each year. (National Institute of Standards and Technology (NIST)–just the cost of routine work-arounds and corrections by users, along with the added cost of buggy software that had to be fixed late in the development process. The real cost of bugs is much higher. –$22.2 billion of that $59.5 billion, or 37%, could be saved through "feasible improvements" in software testing.–“We indulge ourselves with the idea that all software has bugs, so trying harder to get rid of them is pointless perfectionism. Intellectually we should know better” !Software: the product•Software: a strategic business issue, not just a low-level support activity•Can software be “manufactured” like physical products? (software “factories”)–Costs are concentrated on engineering (design) and support–“mythical man-month” Adding people to a project that is late will only worsen the situation. Why?•Efficiency through re-useTimeFailure RateHardwareSoftwareInfant mortalityWear outIdealChangesFailure CurvesActualThe Systems Analyst•Roles–as a CONSULTANT (external)•provide a fresh perspective•disadvantage: organizational culture may not be known–as a SUPPORTING EXPERT–as a CATALYST FOR CHANGE•interact with management•excellent with people and machines•analyze need for change, design change with consensus, implement changeThe Systems Analyst•Qualities–problem solver•good analysis skills•tools and techniques for analysis–communicator–computer skills–knowledge of business processes–self-disciplined and self-motivatedSystems Development Process set of activities, methods, best practices and deliverables that are used to develop and maintain information systems.Process maturityas the development process matures, project costs decrease, timelines improve, productivity and quality increase.Software development - The ProcessGuiding principles•Get the Owners and Users Involved•Establish Phases and Activities•Establish Standards for Development and Documentation•Justify systems as Capital Investments•Don’t be afraid to Cancel or Revise Scope•Divide and Conquer•Design for Growth and ChangeSoftware development - The Process3 Generic Phases•Definition (What)–Customer contact•role of system, scope–Project Planning•risk analysis, resources, cost estimation, schedules–Requirement Analysis•Development (How)–Design–Coding–Testing•Maintenance–Correction of errors–Adaptation–Enhancements•Preliminary Investigation Phase –establishes the project context, scope, budget, staffing, and