Presentation on theme: "1 Chapter 14 Construct, Deliver, and Maintain Systems Projects Accounting Information Systems, 5 th edition James A. Hall."— Presentation transcript:
1 Chapter 14 Construct, Deliver, and Maintain Systems Projects Accounting Information Systems, 5 th edition James A. Hall
2 SDLC major phases 1.Systems strategy 2.Project initiation 3.In-house development 4.Commercial packages 5.Maintenance & support Chapter 14 Chapter 13
Systems Development Life Cycle 1. Systems Strategy - Assessment - Develop Strategic Plan 2. Project Initiation - Feasibility Study - Analysis - Conceptual Design - Cost/Benefit Analysis 2. Project Initiation - Feasibility Study - Analysis - Conceptual Design - Cost/Benefit Analysis 3. In-house Development - Construct - Deliver 4. Commercial Packages - Configure - Test - Roll-out 5. Maintenance & Support - User help desk - Configuration Management - Risk Management & Security 5. Maintenance & Support - User help desk - Configuration Management - Risk Management & Security System Interfaces, Architecture and User Requirements Business Requirements High Priority Proposals undergo Additional Study and Development Feedback: User requests for New Systems Selected System Proposals go forward for Detailed Design New and Revised Systems Enter into Production Business Needs and Strategy Legacy Situation Feedback: User requests for System Improvements and Support Ch13 Ch14
Overview of Phases 3, 4 and 5 zPhase 3 - In-House Development yappropriate when organizations have unique information needs ysteps include: xanalyzing user needs xdesigning processes and databases xcreating user views xprogramming the applications xtesting and implementing the completed system
Overview of Phases 3, 4 and 5 zPhase 4 - Commercial Packages ywhen acceptable, most organizations will seek commercial software package yadvantages: xlower initial cost xshorter implementation time xbetter controls xrigorous testing by the vendor yrisks: xmust adequately meet end users’ needs xmust be compatible with existing systems
Overview of Phases 3, 4 and 5 zPhase 5 - Maintenance and Support yacquiring and implementing the latest software versions of commercial packages ymaking in-house modifications to existing systems to accommodate changing user needs ymay be relatively trivial, such as modifying an application to produce a new report, or more extensive, such as programming new functionality into a system
Phase 3 In-house Development
8 3 problems that account for most system failures… 1.Poorly specified systems requirements communication problems time pressures 2.Lack of user involvement in systems development/selection 3.Ineffective development techniques (for internally developed systems) systems developer end user
Prototyping zProvides preliminary working version of the system zBuilt quickly and relatively inexpensively with the intention it will be modified zEnd users work with the prototype and make suggestions for changes. yA better understanding of the true requirements of the system is achieved.
Computer-Aided Software Engineering (CASE) zCASE technology uses computer systems to build computer systems. zCASE tools are commercial software products consisting of highly integrated applications that support a wide range of SDLC activities.
11 PERT charts zUsed to show relationship among key activities of a systems project zProbably used more for in-house development (than commercial software acquisition)
A D G B C F H I Purchase Equipment Install and Test Equipment Design Data ModelCreate Data Structures E Design Process Code Programs Test Programs Prepare Documentation Convert Data Files Test System Train Personnel Cut Over to New System A-D 3 Weeks A-B 4 Weeks A-C 4 Weeks D-F 2 Weeks B-F 5 Weeks C-E 5 Weeks E-F 3 Weeks F-G 3 Weeks F-I 3 Weeks F-H 4 Weeks H-I 4 Weeks G-I 3 Weeks Construct Phase Deliver Phase Project Evaluation and Review Technique (PERT) PERT charts show the relationship among key activities that constitute the construct and delivery process.
Structured Design Approach zA disciplined way of designing systems from the top down zStarts with the “big picture” of the proposed system and gradually decomposes it into greater detail so that it may be fully understood zUtilizes data flow diagrams (DFDs) and structure diagrams (not necessary to study DFDs)
Systems Design zFollows a logical sequence of events: ymodel the business process and design conceptual views ydesign normalized database tables ydesign physical user views (output and input views) ydevelop process modules yspecify system controls yperform system walkthroughs
Data Modeling zFormalizes data requirements of the business process as conceptual model zEntity-relationship diagram (ERD) yprimary tool for data modeling yused to depict the entities or data objects in system zEach entity in ER diagram is a candidate for a conceptual user view that must be supported by database.
Normalization zUser views in data model must be supported by normalized database tables. zNormalization of database tables: yA process of organizing tables so that entities are represented unambiguously yEliminates data redundancies and associated anomalies yDepends on the extent that the data requirements of all users have been properly specified in the data model yThe resulting databases will support multiple user views zMore detail in chapter 9 about data normalization
Physical User Views: Output Views zOutput is the information produced by the system to support user tasks and decisions. zOutput attributes: -relevant -summarization -except orientation - timely -accurate -complete -concise
Designing Hard Copy Input zItems to Consider: yHow will the document be handled? yHow long will the form be stored and in what type of environment? yHow many copies are required? yWhat size form is necessary? xNon-standard form can cause printing and storage problems.
Designing System Controls zThe last step in the detailed design phase zNeed to consider: ycomputer processing controls ydata base controls ymanual controls over input to and output from the system yoperational environment controls zAllows the design team to review, modify, and evaluate controls with a system-wide perspective that did not exist when each module was being designed independently
Systems Walkthrough zUsually performed by the development team yEnsure that design is free from conceptual errors that could become programmed into the final system zSome firms use a quality assurance (QA) group to perform this task. yAn independent group of programmers, analysts, users, and internal auditors
21 S Y S T E M The Delivery
22 Delivering a system zAppropriate for commercial software or in-house development yTest entire system yDocument the system xDesigner/Programmer documentation (in-house) xOperator documentation (more centralized than distributed) xUser documentation xAccountant/Auditor documentation
23 Conversion of databases zAppropriate for commercial software or in-house development yTransfer of data from old system to new system yValidate data before conversion yReconcile data after conversion yKeep backup copies of old data!
24 Converting to New System Three approaches: zCold turkey cutover (“Big Bang”) - firm switches to new system on particular day and simultaneously terminates old system. Riskiest approach. zPhased cutover - modules are implemented in piecemeal fashion. Risk of devastating failure can be reduced. zParallel cutover - old system and new system are run simultaneously. Safest, yet costliest, approach.
25 Role of Accountants in Construct & Deliver Phases zAccountant should: yProvide technical expertise re: GAAP, GAAS, SEC regulations, SoX, IRS code. ySpecify documentation standards yVerify control adequacy
Phase 4 Commercial Packages
27 4. Commercial Software zFour factors have stimulated growth of commercial software: yrelatively low cost yprevalence of industry-specific vendors ygrowing demand by small businesses ytrend of organizational downsizing and distributed data processing
28 Types of Commercial Software zTurnkey systems: completely finished and tested systems -- ready for implementation. zBackbone systems: provide basic system structure on which to build. zVendor-supported systems: custom-developed and maintained by vendor for customer. zERP systems are difficult to classify because they have characteristics of all of the above.
29 Commercial Software zAdvantages yImplementation time yCost yReliability zDisadvantages yDependence on vendors yNeed for customized systems yMaintenance
30 Steps in Choosing a Commercial Package 1.Needs analysis 2.Send out Request for Proposals (RFP) to prospective vendors to serve as comparative basis for initial screening. 3.Gather facts about each vendor’s system using multiple sources and techniques. 4.Analyze findings and make final selection.
Phase 5 Maintenance and Support
Maintenance and Support zApproximately 80% of the life and costs of SDLC zCan be outsourced or done in-house zEnd user support is a critical aspect of maintenance that can be facilitated by: yknowledge management - method for gathering, organizing, refining, and disseminating user input ygroup memory - method for collecting user input for maintenance and support