Development

1. Development Prepared by: Arjaa Salem Makkawi ID: 10120054 Sec : 2

2. The steps involved in developing an Information System are:  • Analysis • Feasibility Study • System Design • Testing • Implementation • Documentation Developing an Information System

3. This is a very important part in the development of an Information System and involves looking at an organisation or system (such as a nursery school) and finding out how information is being handled at the moment. Analysis

4. If there is no computer system then the first task will be to look at existing manual systems. It is possible to find out about existing systems in a number of ways:  • Talking to the people who work with the system. • Questionnaires to existing users. • Observing how people use the system. • Reading existing manuals. If the aim is to improve an existing computer system the methods of analysis previously mentioned are still important. The analysis phase often includes a feasibility study. At the end of this phase a decision needs to be made as to what software to use. 

5. The aim of a feasibility study is to see whether it is possible to develop a system at a reasonable cost. At the end of the feasibility study a decision is taken whether to proceed or not .A feasibility study contains the general requirements of the proposed system. Let us consider the task of setting up an Information System for a nursery and seeing how Information Technology can help it run more efficiently.  Feasibility study

6. Feasibility study  The study might identify the following general requirements for the system:  • To be simple and easy to use. • To store all relevant details of the members. • To produce membership lists, membership cards and mailing labels. • To produce posters, flyers and similar material advertising the nursery.

7. The areas that need to be considered in the design process are listed below:1. Outputs 2. Inputs 3. File Design4. Hardware5. Software  Design

8. Some of the outputs for a system for a nursery might be: a) Details of the children looked after within the nursery. b)  Address labels for parents of the children.  Design - Outputs

9. To work out the inputs required for a system several questions need to be addressed: What data needs to be entered into the computer system? • How much data needs to be input, and how often? • Where does the data come from? • How will the data be entered into the system?  Design - Inputs

10. How many files are needed and what will their structure be? A nursery membership file might have the following structure: Design - File Design

11. This section covers the types of computers and printers thought suitable for the system being analysed. If the system needs to be on a network, details would be specified here.  Design - Hardware

12. A decision will have to be made as to what software to use. The most common software packages are databases, spreadsheets and word processing packages.  Design - Software

13. Any new system needs to be thoroughly tested before being introduced. First of all, the system should be tested with normal data to see if it works correctly.Secondly, the system is tested with data containing known errors to try and make it fail ('crash').Thirdly, the system is tested with very large amounts of data to see how it can cope. It is important that processing time and response rates remain acceptable with varying amounts of data.  Testing

14. A test plan should be designed before testing commences. Testing

15. There are four general stages of tests: • Unit tests: -Black-box -White-box • Integration tests: -Interface testing: the tester test each interface function. -Use-Case Testing: the tester test each use case. -Interaction Testing: tests each process in a step-by-step fashion -System Interface Testing: test the exchange of data with other systems. • System tests -Usability testing: how convenient the system is to use. -Security testing: how secure the system is. -Performance testing: how well the system performs under heavy load. -Documentationtesting: how accurate the documentation of the system. • Acceptance tests - Alpha testing - Beta testing

16. Implementing or introducing a new system can be done in two ways:  • Direct Implementation • Parallel Running Implementation

17. With this method of implementation the users stop using the manual system and start using the computer system from a given date. The advantage of this method is that it is less costly in effort and time than any other method of implementation. The disadvantage of this method is that if problems occur the users do not have any alternative apart from returning to a manual system which may prove difficult if it has been discontinued.  Implementation - Direct

18. With parallel running, the new system is introduced alongside the existing system. With parallel running both systems (manual and computer, or old computer and new computer system) will be in operation at the same time. This has the advantage that the results from the new system can be compared with those of the old system. However, it has the major disadvantage that each job is done twice and therefore it means a lot of extra work for the users.  Implementation - Parallel Running

19. A number of documents are produced during the development of a new computer application. Essentially there are two types:  • User Guides • Technical Documentation Documentation

20. User guides are written in plain English rather than technical language. The guide should cover how to run the system, how to enter data, how to modify data and how to save and print reports. The guide should include a list of error messages and advice on what to do if something goes wrong. Documentation - User Guides

21. Technical documentation is used to explain a system to a specialist i.e. an analyst / programmer. This document will be used if any changes have to be made to the system. It is a very important document which needs to be fully up-to-date. Documentation - Technical

22. Online Documentation Example

23. Example of template test plan:

24. The End