Systems Analysis and Design: A Comprehensive Overview

1. Welcome to CMPE003 Personal Computer Concepts: Hardware and Software Winter 2003 UC Santa Cruz Instructor: Guy Cox

2. Assignments • Assignment #6 – The Last One  • Due March 12, 2003 • Spreadsheets – (MS Excel) • Generate a monthly budget spreadsheet http://www.soe.ucsc.edu/classes/cmpe003/Winter03/hw6_spreadsheet.html

3. Final Project • Due no later than March 19, 2003 • You can turn in earlier..  • Power Point presentation • 4 pages • Extra points for special effects, animations • Turn in on a floppy/CDROM http://www.soe.ucsc.edu/classes/cmpe003/Winter03/finalproject.html

4. Systems Analysis and Design: The Big Picture Chapter 15

5. Objectives • Define the terms system, analysis, and design • Describe the principal functions of the systems analyst • List and describe the phases of the systems development life cycle • Describe the various data gathering and analysis tools • Describe a selection of systems design tools • Explain the concept of prototyping • Explain the role of the maintenance task in the systems development life cycle

6. Systems Analysis and Design: What is it? • System • organized set of related components established to accomplish certain task • Natural Systems • Cardiovascular system • Planned and placed by people • Water system • Computer system • A system that has computers as one of its components

7. Systems Analysis and Design: What is it? • Systems analysis Process of studying an existing system to determine how it works and how it meets user needs • Systems design Process of developing a plan for an improved system, based upon the results of the systems analysis

8. Systems Analysis and Design:Why do it? • Impetus for change • Internal force, e.g. improved productivity and efficiency • External force, e.g. meet regulatory requirements or resolve customer issues • Authority for change • Approval of higher management

9. Systems Analyst • Professional computer employee who performs analysis and design • Change agent • Overcome reluctance of users to change • Typical career path • Programmer • Programmer / Analyst • Systems Analyst

10. Systems Analyst: Functions Coordination • Schedules and system-related tasks • Personnel • Manager • Programmers • Users • Vendors of computer equipment • Mail room employees • Contractors

11. Systems Analyst: Functions Communication • Oral presentations • Written documentation Planning and design • Plans and designs the new system • Involved from beginning of project through final implementation of the system

12. SDLC: Systems Development Life Cycle • Preliminary investigation • Analysis • Design • Development • Implementation

13. SDLC: Preliminary Investigation • Feasibility study / System survey • Determine the problem • Describe the problem • Understand management decisions • Organizational chart • Informal hierarchy • Produces rough plan and what to do

14. SDLC: Preliminary Investigation Problem Definition • Nature of the problem Separate problem from symptoms of problem • Scope of the project Establish boundaries.. Budget and schedule • Objectives of the project What user thinks system should do

15. SDLC: Preliminary Investigation Report What you have found Recommendations Financially feasible

16. SDLC: Preliminary Investigation Resulting Management Decision • Drop • Fix a simple problem • Authorize the analysis phase

17. SDLC: Analysis • Understand the existing system • Gather data • Analyze data • Establish system requirements

18. SDLC: Analysis – Data Gathering • Written documents • Interviews • Structured • Unstructured • Questionnaires • Observation • Visits by appointment • Participant observation • Sampling

19. SDLC: Analysis – Analyze Data • How the current system works • Determine system requirements • Basis for documentation • Tools • Data flow diagram (DFD) • Decision tables

20. SDLC: Analysis – Data Flow Diagram

21. SDLC: Analysis –Decision Tables

22. SDLC: Analysis – System Requirements • Detailed list of things the system must be able to do • Design is based upon system requirements • Agreement upon requirements is needed before proceeding

23. SDLC: Analysis – Report to Management • Summarize problems • Describe requirements • Cost analysis • Recommendations for next step • Obtain authorization to proceed

24. SDLC: Design • Planning the new system • System Architecture • Two Design Phases • Preliminary design (or external design) • Detail design (or internal design)

25. SDLC: Preliminary Design Major system aspects • Centralized or distributed • Online or batch • PC-based? • How will input be captured? • Necessary reports

26. SDLC: Preliminary Design • Make or buy decision • Packaged software • Meet at least 75% of requirements? • Change business procedures for part or all of remainder? • Customize for part of all of remainder? • Custom software • Programmers write code • Outsourcing • System is developed by external organization

27. SDLC: Preliminary Design • Create an overall plan • Offer alternatives that meet requirements • Explain differences • Evaluate costs

28. SDLC: Preliminary Design • Build a prototype • Limited working system of subset • Does not need true functionality • Output looks like anticipated system output • Working model that can be modified and fine-tuned • Uses high-level software tools – CASE • Best for small-scale systems

29. SDLC: Preliminary Design CASE tools Computer-Aided Software Engineering • Supports specific analysis and design tasks • Integrated environment that supports the entire systems development process

30. SDLC: Preliminary Design Presentation • All alternatives • Selected plan • Prototype of the system • Obtain authorization to proceed

31. SDLC: Detail Design Parts of detail design phase • Output requirements • Input requirements • Files and databases • Systems processing • Systems controls and backup

32. SDLC: Detail Design Output requirements • Medium • Type of reports • Contents

33. SDLC: Detail Design

34. SDLC: Detail Design Input requirements • Medium • Content • Input forms • Validation • Volume

35. SDLC: Detail Design Files and Databases • Organization • Access • Format of records • Coordinate with database administrator regarding external databases and updating

36. SDLC: Detail Design Flowchart Symbols

37. SDLC: Detail Design

38. SDLC: Detail Design Systems Controls and Backup • Insure that input is processed correctly • Prevent fraud and tampering • System journals • Backup of system files

39. SDLC: Detail Design Report to Management • Detailed design specifications report • Presentation • Obtain authorization to proceed

40. SDLC: Development • Doing the work to bring the new system into being • Scheduling

41. SDLC: Development • Programming • Refine the design • Detailed logic flowcharts and pseudocode • Testing • Unit testing • System testing • Volume testing

42. SDLC: Implementation • Converting to the new system • Training • Equipment conversion • File conversion • System conversion • Auditing • Evaluation • Maintenance

43. SDLC: Implementation – Training • Begin during testing • User’s manual (Technical Writers) • Hands-on • Training consideration • Space • Equipment • Data • User’s schedules

44. SDLC: Implementation – Conversion • Equipment • Planning • Installation of new equipment • File • Manual to electronic • Special programs to convert old format to new

45. SDLC: Implementation – Conversion • System • Direct conversion • Phased conversion • Pilot conversion • Parallel conversion

46. SDLC: Implementation –Auditing • Audit trail • Trace output back to source

47. SDLC: Implementation – Evaluation • Working? • Meets original requirements? • Benefits • Meets budget • Improvements

48. SDLC: Implementation – Maintenance Ongoing activity for life of system

49. Have A Great Day