LESSON 1 SYSTEM DEVELOPMENT LIFE CYCLE (SDLC)

1. LESSON 1SYSTEM DEVELOPMENT LIFE CYCLE (SDLC) • What is a system? • A system is a collection of related components that serves a common purpose • System might be • Automated • Manual or • A combination of both

2. SYSTEM DEVELOPMENT LIFE CYCLE (SDLC)

3. PHASE 1: PROBLEM RECOGNITION/INITIAL STUDY • To establish that a problem exists • Manager or user will notify a System Analyst that the problem exists • System Analyst conducts initial study of the system and understands the problems • System Analyst conducts a feasibility study and produces a feasibility report • Cost Benefit Analysis carried out

4. COST/BENEFIT ANALYSIS • A cost/benefit analysis can be carried out to decide whether or not a new system is feasible • It is a procedure for evaluating costs to see if they are justified by the benefits they deliver • In cost/benefit analysis, we will look at • Tangible cost • Intangible cost • Tangible benefits • Intangible benefits

5. PHASE 2: SYSTEM ANALYSIS & DESIGN • 2 main activities ANALYSIS and DESIGN • ANALYSIS • To determine the requirements of the proposed new system • Tools that will be used to collect facts are • Interview • Questionnaire • Examine existing documents • Examine current procedures • Prototyping

6. PHASE 2: SYSTEM ANALYSIS & DESIGN • Tools used to document new proposed system • Data flow diagram • Data dictionary • Data models • System flowchart • The output from this phase will be the requirements specification document • A presentation by the SA to the users is required in order to verify the findings

7. PHASE 2: SYSTEM ANALYSIS & DESIGN • Design • To design a new system that fulfills the requirements of users and their management • The phase will produce the design specification which contain • System specification • Tools used • Data flow diagram • Data models: e.g. Entity Relationship model • System flowchart

8. PHASE 2: SYSTEM ANALYSIS & DESIGN • System specification includes • Information flow • File storage organisation • Program requirements • Outline of user’s operations manual • Input and Output forms will be designed by analyst • Analyst determines staffing requirements and designs procedures and workflow

9. PHASE 2: SYSTEM ANALYSIS & DESIGN • User, manager and analyst review the design specifications for accuracy and completeness • Analyst will oversee preparation of the site and installation of the necessary equipment

10. PHASE 3: PROGRAM DESIGN • The phase will produce the Program Specification • Tools used • Flowchart • Structured Chart : e.g. JSP • Pseudocode • Decision Table

11. PHASE 3: PROGRAM DESIGN • Program Specification is a description of procedures which a program will do • It is developed by System Analyst/Senior Programmer • Contents • Objectives of the program • Input specification • Output specification • Processing specification • Scope and limitations

12. PHASE 3: PROGRAM DESIGN Program Specification 1. Program Objective 2. Input Specification • Describes all file specifications • Record structure, format/layout by the program • Field specifications, type/length • Define the data and file format 3. Output Specification • Describes the layout of record table format and structure • Screens and report layout 4. Processing Specification • Describe the methods used to process the field and record structure 5. Scope and limitation

13. PHASE 3: PROGRAM DESIGN • Database designer will design appropriate database for the new system • Analyst plans and supervises the writing, testing and correction of the program • User will also verify that the system functions as intended

14. PHASE 4: DEVELOPMENT • Convert design into workable solutions (programs) • 2 main activities • File creation • Application program creating • Detailed documentation on files and program • Input and output specifications • Data dictionary • Operating instruction

15. PHASE 5: TESTING • Carried out according to schedule prepared by SA or senior programmer • Changes can be made in any of the previous stages to rectify errors or problems discovered • Documents generated are • Test log • Test plan • Test data • Test results (expected and actual)

16. PHASE 6: IMPLEMENTATION • Convert from the old system to the new system • Output from this phase is a working system • This stage covers • User training • Data conversion • Control procedures for changeover • The System Analyst plans and supervises the implementation

17. PHASE 6: IMPLEMENTATION • 4 implementation methods • Direct changeover • Parallel changeover • Pilot changeover • Phase/Gradual changeover

18. PHASE 7: MAINTENANCE • It occurs because of defects in the system • Bugs in the system • Changing user or business requirements • Changing in government policy • New hardware/software • Programmers will then modify the programs • The modified program must be tested • All documentation related to the changes must be updated

19. PHASE 8: REVIEW • To identify the strength and weakness of the new system • Carried out by a person who has not been involved in the design and development stages • Review software, computer activities and human procedures • Review include objectives met, cost performances, standard and recommendations • Involve users, systems, operation and programming groups

20. PHASE 8: REVIEW • Maintenance may be done to enhance the system • Redesigning may be needed, if required (thus whole cycle starts again.)