GCSE ICT The Systems Life Cycle

1. GCSE ICT – The Systems Life Cycle Year 10

2. The Systems Life Cycle Objectives: To learn the stages in the systems life cycle To understand the role of the systems analyst

3. The systems life cycle

4. Why introduce a new system? The current system may no longer be suitable for its purpose. Technological developments may have made the current system redundant or outdated. The current system may be too inflexible or expensive to maintain, or may reduce the organisation’s ability to respond quickly enough to customer’s demands. Better management information is required for decision-making. The provision of better customer service.

5. The role of the systems analyst

6. The feasibility study The purpose is to see if it is worth going ahead with a new system.

7. Feasibility study questions What are the problems with the existing system? Can the problems be solved? How much will it cost? What is the scope of the project? What must the new system do? What are the benefits of a new system? What are the recommendations?

8. The feasibility report The findings of the feasibility study are summarised in a document called the feasibility report. The report is shown to senior managers, who use it to decide whether or not to go ahead with the new system.

9. The feasibility study

10. Analysis - Investigating the current system Interviewing staff Examining current business and systems documents and output. Sending out questionnaires and analysing responses Observation of current procedures, by spending time in various departments.

11. Analysis – Understanding the problems Identifying problems with the current system Identifying the needs of users Investigating similar systems elsewhere Investigating what input, processing and output are needed Establishing what tasks need to be completed Establishing deadlines for completion of tasks

12. Analysis – Tools Flow charts Data flow diagrams Structure diagrams

13. Design The design stage looks at how the new system will be built. Ict systems can be broken down into: Input Process Output This stage looks at the design of all three. When the design is complete, a document called a design specification is created. This is shown to users for their comments.

14. The Design Specification The hardware platform (PC, mainframe) The software (off the shelf, bespoke) The outputs (hardware, reports) The processing (sorting, searching, grouping) The inputs (data capture, input devices) Storage (devices, method) Security and backup The user interface (GUI, command line) The modular design of each program in the application The test plan and test data Conversion plan Documentation including systems and operations documentation. Later, a user manual will be produced.

15. Implementation Programs written, tested and documented Data loaded from old system to new system Staff trained on new system May be parallel running of both systems for a while or direct implementation or phased implementation System maintained by keeping it up-to-date, solving any problems and writing new programs when required.

16. Testing As soon as a system is developed it should be checked against user requirements to ensure the system does everything the user wants.

17. Testing – Four stages System tested with data that contains no errors to see if it produces correct results. Known errors are introduced into the data to see how the system handles them Output is produced and checked Extreme data is entered to ensure range checks are included as part of validation

18. Test plan

19. Documentation Two types of documentation are produced: User guide: so that users can learn to use the system Technical documentation: so that the system can be maintained

20. Evaluation Does the system meet all user needs? Is it functioning correctly? Are any improvements needed?

21. Maintenance Providing support for users Providing enhancements Creating patches (fixing bugs) Improving software (updates)