1. IS Analysis & Design Chapter 9 The Systems Development Life Cycle © The McGraw-Hill Companies, Inc., 2000

2. Ch 9© The McGraw-Hill Companies, Inc., 20002 CCI Overview Six phases of the SDLC –First phase –Second phase –Third phase –Fourth phase –Fifth phase –Sixth phase

3. Ch 9© The McGraw-Hill Companies, Inc., 20003 CCI Systems Collection of related components that interact to perform a task in order to accomplish a goal Computer-based information systems and their interaction with the people of the organization, its suppliers, and buyers define the effectiveness and efficiency of the systems

4. Ch 9© The McGraw-Hill Companies, Inc., 20004 CCI System Review Marketing opportunities Government regulations New technology Merger or acquisition with another company Exponential changes in any portion of the business process

5. Ch 9© The McGraw-Hill Companies, Inc., 20005 CCI Formal Process Systems Development Life Cycle –SDLC Formal assignment allows for milestones, goals, and assessment Users play a vital role –things are not all written or handled in an intuitive way –without adaptation, any new system is a failure

6. Ch 9© The McGraw-Hill Companies, Inc., 20006 CCI User Participation in SDLC Current system methods Joint Application Development (JAD) –analysts and users at equivalent levels work together to define, discuss, suggest improvement Explanation of departmental objectives and requirements

7. Ch 9© The McGraw-Hill Companies, Inc., 20007 CCI More User... Reports definition and format Project approval and budgets Evaluation and acceptance testing Documentation and procedure documentation Briefings and training sessions –train the trainer Finally, user’s daily execution of system

8. Ch 9© The McGraw-Hill Companies, Inc., 20008 CCI System Failure The large majority of failures are because system does not define the way business is conducted User requirements are not met

9. Ch 9© The McGraw-Hill Companies, Inc., 20009 CCI Additional Reasons for Failure Lack of communication Continuing a project that should have been cancelled –like sunk costs in economics, a project should not be continued based on the money spent –a project should be continued based on the expected revenue or benefit when the project is completed

10. Ch 9© The McGraw-Hill Companies, Inc., 200010 CCI More Failure Reasons System integration Technological incompetence –the risk of failure in system implementation to a large degree is based on the knowledge base of the employees Major changes in middle of project Lack of user training

11. Ch 9© The McGraw-Hill Companies, Inc., 200011 CCI Information Systems Money allocation for information systems processing functions –hardware –software –staff support Multiplicity of effort –must coordinate full system - automated and non-automated - goals and objectives

12. Ch 9© The McGraw-Hill Companies, Inc., 200012 CCI Financial Outlay Not met users needs Unnecessary hardware acquisition Insufficient hardware Software inadequately tested Software performance inadequate

13. Ch 9© The McGraw-Hill Companies, Inc., 200013 CCI Phases Some phases are cross-life-cycle activities –Fact-finding –Documentation and presentation –Estimation and measurement –Feasibility analysis –Project management –Process management

14. Ch 9© The McGraw-Hill Companies, Inc., 200014 CCI Major Phases Preliminary Investigation Systems analysis Systems design Systems development Systems implementation Systems maintenance

15. Ch 9© The McGraw-Hill Companies, Inc., 200015 CCI Who Participates? Users Management –middle and upper Technical taff The less involvement, the more likelihood of failure

16. Ch 9© The McGraw-Hill Companies, Inc., 200016 CCI SDLC Leader –head systems analyst, systems engineer, or project leader Use system approach –complete, accurate, relevant, timely (CART) Often, a committee determines first step of feasibility allowing the project funding and execution

17. Ch 9© The McGraw-Hill Companies, Inc., 200017 CCI Preliminary Investigation ٭Conduct preliminary analysis ٭Propose alternative solutions ٭Describe costs and benefits ٭Submit preliminary plan with recommendations

18. Ch 9© The McGraw-Hill Companies, Inc., 200018 CCI Preliminary Investigation Business Process Reengineering (BPR) –redefines the fundamental business processes BPR –independent of information technology Document nature and scope of the problems

19. Ch 9© The McGraw-Hill Companies, Inc., 200019 CCI Propose Alternative Solutions Leave as is –not justify –part of a Electronic Data Interchange requiring system conforming Improve the system –upgrading –retraining Develop a new system – current computer system does not reflect or properly support the business process

20. Ch 9© The McGraw-Hill Companies, Inc., 200020 CCI Describe the Costs and Benefits Tangible –actual dollar savings –increase in system efficiency Intangible –done for strategic competitive advantages –done for market share increase

21. Ch 9© The McGraw-Hill Companies, Inc., 200021 CCI Preliminary Plan Written report submitted Includes major agreement by all three levels of business –transactional, middle management, strategic

22. Ch 9© The McGraw-Hill Companies, Inc., 200022 CCI Detailed Systems Analysis Data gathering –surveys, questionnaires, observations, random and stratified sampling, structured and unstructured interviews Data analyzing –CASE (Computer-Aided Software Engineering tools tie together dictionary/encyclopedia for consistent use of terms, insure correct system flow, data integrity, and report generation

23. Ch 9© The McGraw-Hill Companies, Inc., 200023 CCI CASE Data dictionary –encyclopedia or repository Data flow and system diagrams –allows parallel processing beyond a data flow chart, integrating the system being examined with the entire enterprise Connectivity diagrams –defines communications through networks Grid charts and decision tables ensure all cases are met

24. Ch 9© The McGraw-Hill Companies, Inc., 200024 CCI Systems Analysis WHAT HOWDescribes WHAT a system is doing and what it should do without regard to HOW the process is to be accomplished

25. Ch 9© The McGraw-Hill Companies, Inc., 200025 CCI OOA Object-oriented analysis –instead of structured concerns in terms of processes and data –objects consisting of attributes and methods are defined, more closely reflecting real-life systems within an organization –Software Engineering Institute has scientifically proven that this methodology facilitates fewer errors and less maintenance than structured system designs

26. Ch 9© The McGraw-Hill Companies, Inc., 200026 CCI Final Analysis Outcome Requirements statement –defines boundaries for system design –provides the basis for testing scripts during system implementation

27. Ch 9© The McGraw-Hill Companies, Inc., 200027 CCI System Design Preliminary design –general functional capabilities –further definition through prototyping with user input Detailed design –input and output requirements –processing and system controls –backup and contingency designs

28. Ch 9© The McGraw-Hill Companies, Inc., 200028 CCI CASE in Systems Design Front-end, or upper CASE –used for preliminary investigation, analysis and design Back-end, or lower CASE –systems development and implementation –coding and testing support future maintenance testing and proofs of correctness

29. Ch 9© The McGraw-Hill Companies, Inc., 200029 CCI Project Management Determines resources of people and systems Maps out interaction to resolve conflicts and bottlenecks Running project management software does not in itself create project management –it is the act of examining and changing project software that creates the management Includes Gantt and PERT charts

30. Ch 9© The McGraw-Hill Companies, Inc., 200030 CCI Gantt and PERT charts Gantt shows bar chart diagrams –used for upper management to simply showing project progress

31. Ch 9© The McGraw-Hill Companies, Inc., 200031 CCI PERT Program Evaluation and Review Technique –shows timing and relationship –clearly show critical path, where delays in the project will slow total completion time

32. Ch 9© The McGraw-Hill Companies, Inc., 200032 CCI Detailed Design Output requirements Input requirements Storage requirements Processing and network requirements System controls and backup

33. Ch 9© The McGraw-Hill Companies, Inc., 200033 CCI Final Design Output Design specifications Including continuing feasibility analysis – economic, technical, and operational

34. Ch 9© The McGraw-Hill Companies, Inc., 200034 CCI System Development Acquisition of software/hardware –make and/or buy Development of software –customization of shrink-wrap software Unit testing System testing

35. Ch 9© The McGraw-Hill Companies, Inc., 200035 CCI System Implementation Conversion –facilities –hardware –database –software Direct, parallel, phased, or pilot –rarely are business or financial institutions employing direct because of accountability issues

36. Ch 9© The McGraw-Hill Companies, Inc., 200036 CCI Finally in Implementation Completed documentation –integrated on and off-line Train the users

37. Ch 9© The McGraw-Hill Companies, Inc., 200037 CCI System Maintenance Auditing Evaluation Types of maintenance –perfective –corrective –enhancement