Introduction to Systems Development Life Cycle

1. Introduction to Systems Development Life Cycle

2. The Information Systems Life Cycle • What are the four steps in the information systems life cycle (ISLC)? • System development • System implementation • Syetem operation • System obsolencence

4. The Systems Development Life Cycle • What are the five steps in the systems development life cycle (SDLC)? • Systems analysis • Conceptual design • Physical design • Implementation and conversion • Operations and maintenance

6. The Systems Development Life Cycle: Systems Analysis Systems Analysis Do initial investigation Do system survey Do feasibility study Determine information needs and system requirements Deliver systems requirements Conceptual Design

7. The Systems Development Life Cycle: Conceptual Design Conceptual Design Identify and evaluate design alternatives Develop design specifications Deliver conceptual design requirements Physical Design

8. The Systems Development Life Cycle: Physical Design Physical Design Design output Design database Design input Develop programs Develop procedures Design controls Deliver developed system Implementation and Conversion

9. The Systems Development Life Cycle: Implementation and Conversion Implementation and Conversion Develop plan Install hardware and software Train personnel, test the system Complete documentation Convert from old to new system Fine-tune and review Deliver operational system Operation and Maintenance

10. The Systems Development Life Cycle: Operation and Maintenance Feasibility analysis and decision points: Economic Feasibility Technical Feasibility Legal Feasibility Scheduling Feasibility Operational Feasibility Operation and Maintenance Operate system Modify system Do ongoing maintenance Deliver improved system Systems Analysis

11. Planning Systems Development • Why is planning an important step in systems development? • consistency • efficiency • cutting edge • lower costs • adaptability

12. Planning Systems Development • What types of systems development plans are needed? • project development plan • master plan

13. Planning Techniques • Two techniques for scheduling and monitoring systems development activities are: • PERT (program evaluation and review technique) • PERT requires that all activities and the precedent and subsequent relationships among them be identified. • Gantt chart • A bar chart with project activities listed on the left-hand side and units of time across the top

14. Planning Techniques: Gantt Chart Project Planning Chart (Sample Gantt Chart) ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Activity Week Starting 1 2 3 4 5 6 7 8

15. Gantt Chart

16. PERT Chart

17. Microsoft Project Gantt Chart

18. Microsoft Project PERT Chart

19. Systems Analysis • There are five steps in the analysis phase: • Initial investigation • Systems survey • Feasibility study • Information needs and systems requirements • Systems analysis report

20. Systems Analysis • When a new or improved system is needed, a written request for systems developmentis prepared. • The request describes the current system’s problems, why the change is needed, and the proposed system’s goals and objectives. • It also describes the anticipated benefits and costs.

21. Sample Request for System Services

22. Sample Problem Statements

23. Feasibility Analysis • Systems analysis is the first step in the systems development life cycle (SDLC). • A feasibility study(also called a business case) is prepared during systems analysis and updated as necessary during the remaining steps in the SDLC. • The steering committee uses the study to decide whether to terminate a project, proceed unconditionally, or proceed conditionally.

24. Feasibility Analysis • What five important aspects need to be considered during a feasibility study? • Technical feasibility • Operational feasibility • Legal feasibility • Scheduling feasibility • Economic feasibility

25. Feasibility Analysis • Economic feasibility is the most frequently analyzed of the five aspects. • What is the basic framework for feasibility analysis? • capital budgeting model

26. Feasibility Analysis • What are some capital budgeting techniques? • payback period • net present value (NPV) • internal rate of return (IRR)

27. Candidate Systems Matrix

28. Candidate Systems Matrix (cont.)

29. Feasibility Matrix

30. Typical System Proposal Outline • Introduction • Purpose of the report • Background of the project leading to this report • Scope of the report • Structure of the report • Tools and techniques used • Solution generated • Feasibility analysis (cost-benefit) • Information systems requirements • Alternative solutions and feasibility analysis • Recommendations • Appendices

31. Computer-Aided Software Engineering (CASE) • CASE is an integrated package of computer-based tools that automate important aspects of the software development process. • CASE tools are used to plan, analyze, design, program, and maintain an information system. • They are also used to enhance the efforts of managers, users, and programmers in understanding information needs.

32. Computer-Aided Software Engineering (CASE) • CASE tools do not replace skilled designers; instead they provide a host of self-integrated tools that give developers effective support for all SDLC phases. • CASE software typically has tools for strategic planning, project and system management, database design, screen and report layout, and automatic code generation.

33. CASE Tool Architecture

34. Computer-Aided Software Engineering (CASE) Advantages of CASE Technology Improved productivity Improved program quality Cost savings Improved control procedures Simplified documentation

35. Computer-Aided Software Engineering (CASE) Disadvantages of CASE Technology Incompatibility Cost Unmet expectations

36. Systems Design, Implementation, and Operation

37. Conceptual Systems Design • In the conceptual systems design phase, a general framework is developed for implementing user requirements and solving problems identified in the analysis phase. • What are the three steps in conceptual design? • Evaluate design alternatives. • Prepare design specifications. • Prepare conceptual systems design report.

38. Conceptual Systems Design Systems analysis Evaluate design alternatives Prepare design specifications Prepare conceptual systems design report

39. Conceptual Systems Design • Evaluate design alternatives: • The design team should identify and evaluate design alternatives using the following criteria: • How well it meets organizational and system objectives • How well it meets users’ needs • Whether it is economically feasible • Its advantages and disadvantages

40. Conceptual Systems Design • Prepare design specifications: • Once a design alternative has been selected, the team develops the conceptual design specificationsfor the following elements: • Output • Data storage • Input • Processing procedures and operations

41. Conceptual Systems Design • Prepare conceptual systems design report: • At the end of the conceptual design a conceptual systems design reportis developed and submitted. • To guide physical systems design activities • To communicate how management and user information needs will be met • To help assess systems’ feasibility

42. Physical Systems Design • Physical design translates the broad, user-oriented AIS requirements of conceptual design into detailed specifications that are used to code and test the computer program. Conceptual systems design Physical systems design

43. Physical Systems Design: Output Design • The objective of output design is to determine the characteristics of reports, documents, and screen displays. • Output fits into one of four categories: • Scheduled reports • Special-purpose analysis • Triggered exception reports • Demand reports

44. Physical Systems Design: File and Database Design • What are some file and database designconsiderations? • medium of storage • organization and access • processing mode • maintenance • size and activity level

45. Physical Systems Design: Input Design • When evaluating input design, the design team must identify the different types of data input and optimal input method. • What are the two principal types of data input? • Forms • Computer screens

46. Physical Systems Design: Program Design • Program designis one of the most time-consuming activities in the entire SDLC. • Programs should be subdivided into small, well-defined modules to reduce complexity. • What is this referred to as? • structured programming • Modules should interact with a control module rather than with each other.

47. Physical Systems Design: Procedures Design • Procedures designshould answer the who, what, where, and how questions related to all AIS activities. • What should procedures cover? • input preparation • transaction processing • error detection and corrections • controls

48. Physical Systems Design: Procedures Design What should procedures cover? (continued) • reconciliation of balances • database access • output preparation and distribution • computer operator instructions

49. Physical Systems Design: Control Design What are some control designconsiderations?

50. Physical Systems Design Report • At the end of the physical design phase the team prepares a physical systems design report. • This report becomes the basis for management’s decision whether to proceed to the implementation phase.