1. Unit F451 Computer Fundamentals 3.1.1 Components of a Computer System 3.1.2 Software 3.1.3 Data: Its representation, structure and management in information systems 3.1.4 Hardware 3.1.5 Data transmission 3.1.6 Implications of computer use

2. 3.1.2 Software Module Covers ● The systems development life cycle ● Generic applications software ● Operating systems ● User interfaces ● Utilities

3. Candidates should be able to: a. describe the stages of the systems life cycle; b. explain the importance of defining a problem accurately; c. describe the function and purpose of a feasibility study; d. explain the importance of determining the information requirements of a system and describe different methods of fact finding, including questionnaires, observation, and structured interviews, highlighting the advantages and disadvantages of each method; e. describe what is involved when analysing the requirements of a system, explaining the nature of the requirements specification and its content, including current data structures, inputs, outputs and processing represented in diagrammatic form (data flow diagrams, system flowcharts), identify inefficiencies/problems in the current system; f. describe a design specification including input design, diagrammatic depiction of the overall system, processing, data structure design and output design; g. explain the importance of evaluating the system, and how to identify the criteria used for evaluation; h. explain the content and importance of different types of documentation at different stages in the system life cycle, including the technical and user manuals; i. explain the importance of system testing and installation planning; j. explain the purpose of maintaining the system, and explain the need for system review and reassessment, understanding that software has a limited life span; k. describe prototyping to demonstrate how a solution will appear; l. describe the spiral and waterfall models of the systems life cycle; m. identify the features of common applications found in business, commercial and industrial applications: eg stock control, order processing, payroll, process control, point-of-sale systems, marketing, computer-aided design (CAD), and computer-aided manufacture (CAM); n. identify and justify generic applications software for particular application areas, eg word processing, spreadsheets, desktop publishing (DTP), presentation software, drawing packages; o. identify and justify application areas for which custom-written applications software is appropriate; p. describe the characteristics of knowledge-based systems; q. describe the purpose of operating systems; r. describe the characteristics of different types of operating systems and their uses: batch, real-time, single-user, multi-user, multi-tasking and distributed systems; s. describe a range of applications requiring batch processing, and applications in which a rapid response is required; t. identify and describe the purpose of different types of user interface: forms, menus, GUI, natural language and command line, suggesting the characteristics of user interfaces that make them appropriate for different types of user; u. discuss the importance of good interface design; v. identify and describe the purpose of a range of utilities, eg compression software, hardware drivers, anti-virus software, file handlers.

4. 3.1.1 Components of a Computer System Module Outcomes Candidates should be able to: 1. Define the terms hardware, software, input device, storage device and output device; 2. Describe the purpose of input devices, storage devices and output devices; 3. Describe the different roles and functions of systems software and applications packages.

5. Lesson Objectives Describe the: stages of the systems life cycle.

6. Systems Lifecycle Large Systems Development projects can involve large groups of people working for long periods of time. For such a project to be successful it must be approached in a well planned and methodical way. The system life cycle allows software development to be approached in a number of sequential stages. There are a number of different development models but most follow the same basic pattern.

7. Feasibility study Analysis Design Programming Installation Maintenance Testing

8. Why create a new system? The current system is not suitable for purpose. Technological developments may have made the current system redundant. The current system may be too inflexible or expensive to maintain.

9. Feasibility study Once the need for a computer system has been recognised a Feasibility Study must be carried out. A Feasibility Study aims to look at a problem and decide whether it is worth proceeding with the development. It usually looks at 5 main areas:

10. Feasibility study Legal feasibility :- is the proposed system legal, data protection act etc. Economic feasibility :- is the system likely to be cost effective? Technical feasibility :- Does the technology exist to solve the problem? Time-frame feasibility :- Can the system be developed in the desired time frame? Operational feasibility :- can the client adequately support the new system?

11. Analysis The Requirements Analysis stage involves a detailed look at the current system and what will be required of a new system. Details of the current system and requirements for he new system can be found in a number of ways. Typically: 1. Interviewing staff at different levels of the organisation. 2. Examining existing business and system documents. 3. Using questionnaires to obtain feedback from staff. 4. Observe current procedures first hand. At the end if this process a Data Flow Diagram (DFD) may be used to describe the way information moves around the current system. (we will look at these in lots of depth later on).

12. Design At this stage the a suitable solution to the problem is designed. The design will probably include: 1. Hardware specifications, graphics cards, networking etc. 2. Software specifications, languages to be used, COTTS to be used etc. 3. The user interface, how will the user interact with the computer system. 4. Inputs\Outputs from the system. 5. A testing and evaluation strategy.

13. Programming The solution designed in the last stage is created.

14. Testing The software is tested to make sure it meets users requirements. There are lots of different testing methodologies (most of which you’re going to have to learn). Two you may have heard of already include Alpha and Beta Testing. Alpha Testing – (Acceptance Testing) takes place within the development company to eliminate any obvious problems. Beta Testing – Involves releasing the product early to a number of customers who agree to report any problems they find.

15. Installation This is the stage when people begin to use the system. There are three main ways of installing a new system: Direct change over – The user stops using the old system today and starts using the new system tomorrow. Parallel conversion – The old system continues along side the new system for limited time period. Phased conversion – Different modules of the new system are introduced over time.

16. Maintenance It is impossible to create a system that does not need to be maintained. Maintenance will be required for a number of reasons including, errors in the software, new user requirements, new hardware developments. Maintaining the system is by far the most expensive part of the system life cycle (some estimates up to 80% of the cost of the system). Good analysis, design and testing should all reduce the need for maintanence.

17. Feasibility study Analysis Design Programming Installation Maintenance Testing