Presentation on theme: "Construct, Deliver, and Maintain Systems Projects"— Presentation transcript:
1Construct, Deliver, and Maintain Systems Projects Chapter 14Construct, Deliver, and Maintain Systems ProjectsAccounting Information Systems,5th editionJames A. Hall1
25 major phases SDLC major phases Systems strategy Project initiation In-house developmentCommercial packagesMaintenance & supportChapter 13Chapter 145 major phases
3Systems Development Life Cycle Business Needs andStrategyLegacy SituationBusiness Requirements1. Systems Strategy - Assessment - Develop Strategic PlanCh13Feedback: User requests for New SystemsSystem Interfaces, Architecture and User RequirementsHigh Priority Proposals undergo Additional Study and Development2. Project Initiation- Feasibility Study - Analysis- Conceptual Design- Cost/Benefit AnalysisCh13Feedback: User requests for System Improvements and SupportSelected System Proposals go forward for Detailed DesignNOTE: This is used also as Figure 14-1.3. In-house Development - Construct - Deliver4. Commercial Packages - Configure - Test - Roll-outCh14Ch14New and Revised Systems Enter into Production5. Maintenance & Support - User help desk- Configuration Management- Risk Management & SecurityCh14
4Overview of Phases 3, 4 and 5 Phase 3 - In-House Development appropriate when organizations have unique information needssteps include:analyzing user needsdesigning processes and databasescreating user viewsprogramming the applicationstesting and implementing the completed system22
5Overview of Phases 3, 4 and 5 Phase 4 - Commercial Packages when acceptable, most organizations will seek commercial software packageadvantages:lower initial costshorter implementation timebetter controlsrigorous testing by the vendorrisks:must adequately meet end users’ needsmust be compatible with existing systems22
6Overview of Phases 3, 4 and 5 Phase 5 - Maintenance and Support acquiring and implementing the latest software versions of commercial packagesmaking in-house modifications to existing systems to accommodate changing user needsmay be relatively trivial, such as modifying an application to produce a new report, or more extensive, such as programming new functionality into a system22
83 problems that account for most system failures… Poorly specified systems requirementscommunication problemstime pressuresLack of user involvementin systems development/selection3. Ineffective development techniques(for internally developed systems)systemsdeveloperenduser8
9Prototyping Provides preliminary working version of the system Built quickly and relatively inexpensively with the intention it will be modifiedEnd users work with the prototype and make suggestions for changes.A better understanding of the true requirements of the system is achieved.10
10Computer-Aided Software Engineering (CASE) CASE technology uses computer systems to build computer systems.CASE tools are commercial software products consisting of highly integrated applications that support a wide range of SDLC activities.12
11PERT chartsUsed to show relationship among key activities of a systems projectProbably used more for in-house development (than commercial software acquisition)
12Project Evaluation and Review Technique (PERT) Deliver PhaseConstruct PhaseDGA-D 3 WeeksPurchase EquipmentInstall and Test EquipmentD-F 2 WeeksPrepare DocumentationF-G 3 WeeksG-I 3 WeeksTrain PersonnelA-B 4 WeeksB-F 5 WeeksF-I 3 WeeksDesign Data ModelCreate Data StructuresConvert Data FilesABFIE-F 3 WeeksTest ProgramsH-I 4 WeeksDesign ProcessCut Over to New SystemA-C 4 WeeksF-H 4 WeeksC-E 5 WeeksTest SystemCCode ProgramsEHPERT charts show the relationship among key activities that constitute the construct and delivery process.
13Structured Design Approach A disciplined way of designing systems from the top downStarts with the “big picture” of the proposed system and gradually decomposes it into greater detail so that it may be fully understoodUtilizes data flow diagrams (DFDs) and structure diagrams (not necessary to study DFDs)
14Systems Design Follows a logical sequence of events: model the business process and design conceptual viewsdesign normalized database tablesdesign physical user views (output and input views)develop process modulesspecify system controlsperform system walkthroughs3
15Data ModelingFormalizes data requirements of the business process as conceptual modelEntity-relationship diagram (ERD)primary tool for data modelingused to depict the entities or data objects in systemEach entity in ER diagram is a candidate for a conceptual user view that must be supported by database.4
16NormalizationUser views in data model must be supported by normalized database tables.Normalization of database tables:A process of organizing tables so that entities are represented unambiguouslyEliminates data redundancies and associated anomaliesDepends on the extent that the data requirements of all users have been properly specified in the data modelThe resulting databases will support multiple user viewsMore detail in chapter 9 about data normalization
17Physical User Views: Output Views Output is the information produced by the system to support user tasks and decisions.Output attributes:-relevant-summarization-except orientation-timely -accurate -complete -concise11
18Designing Hard Copy Input Items to Consider:How will the document be handled?How long will the form be stored and in what type of environment?How many copies are required?What size form is necessary?Non-standard form can cause printing and storage problems.18
19Designing System Controls The last step in the detailed design phaseNeed to consider:computer processing controlsdata base controlsmanual controls over input to and output from the systemoperational environment controlsAllows the design team to review, modify, and evaluate controls with a system-wide perspective that did not exist when each module was being designed independently29
20Systems Walkthrough Usually performed by the development team Ensure that design is free from conceptual errors that could become programmed into the final systemSome firms use a quality assurance (QA) group to perform this task.An independent group of programmers, analysts, users, and internal auditors30
22Delivering a systemAppropriate for commercial software or in-house developmentTest entire systemDocument the systemDesigner/Programmer documentation (in-house)Operator documentation (more centralized than distributed)User documentationAccountant/Auditor documentation
23Conversion of databases Appropriate for commercial software or in-house developmentTransfer of data from old system to new systemValidate data before conversionReconcile data after conversionKeep backup copies of old data!
24Converting to New System Three approaches:Cold turkey cutover (“Big Bang”) - firm switches to new system on particular day and simultaneously terminates old system. Riskiest approach.Phased cutover - modules are implemented in piecemeal fashion. Risk of devastating failure can be reduced.Parallel cutover - old system and new system are run simultaneously. Safest, yet costliest, approach.41
25Role of Accountants in Construct & Deliver Phases Accountant should:Provide technical expertise re: GAAP, GAAS, SEC regulations, SoX, IRS code.Specify documentation standardsVerify control adequacyWhat are “escapable costs” ?What would be a reasonable interest rate right now? (5.5% on 10/31/01)
274. Commercial SoftwareFour factors have stimulated growth of commercial software:relatively low costprevalence of industry-specific vendorsgrowing demand by small businessestrend of organizational downsizing and distributed data processing
28Types of Commercial Software Turnkey systems: completely finished and tested systems -- ready for implementation.Backbone systems: provide basic system structure on which to build.Vendor-supported systems: custom-developed and maintained by vendor for customer.ERP systems are difficult to classify because they have characteristics of all of the above.Which category would you put Great Plains Dynamics in?
29Commercial Software Advantages Disadvantages Implementation time Cost ReliabilityDisadvantagesDependence on vendorsNeed for customized systemsMaintenance
30Steps in Choosing a Commercial Package Needs analysisSend out Request for Proposals (RFP) to prospective vendors to serve as comparative basis for initial screening.Gather facts about each vendor’s system using multiple sources and techniques.Analyze findings and make final selection.
32Maintenance and Support Approximately 80% of the life and costs of SDLCCan be outsourced or done in-houseEnd user support is a critical aspect of maintenance that can be facilitated by:knowledge management - method for gathering, organizing, refining, and disseminating user inputgroup memory - method for collecting user input for maintenance and support