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

Development

Developing an Information System

The steps involved in developing an Information System are: 

AnalysisFeasibility StudySystem DesignTestingImplementationDocumentation

Analysis  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.

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. 

Feasibility study

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 

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.

Design

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

Design - OutputsSome 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. 

NameSmith, TonyJackson, JakeTimms, TonyFogett, Carol

Address12 Fields Rd9 Man Gdns87 Colly Row9 Shaw St

Telephone No.0543 34455450563 95457520543 86536530563 9657564

Membership No.001342001234001789001455

Mrs Jackson9 Man GdnsTodthopeTD3 5TT

Mr Timms87 Colly RowTodthopeTD3 8DE

Mrs Fogett9 Shaw StreetTodthopeTD3 3HG

Mr Smith12 Fields RoadTodthopeTD3 7HJ

Design - Inputs

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 - File Design How many files are needed and what will their structure be? A

nursery membership file might have the following structure:Field Type Length Example

Membership No.

Numeric 6 352600

Surname Text 20 McSweeney

First Name Text 15 Jane

Address line 1 Text 25 3 Longlane

Address line 2 Text 25 London

Post Code Alpha numeric 10 N1 1TH

Telephone No. Alpha numeric 10 0181-366-1234

Fees Paid Text 1 Y

Fee Date Date 8 22/04/97

Design - Hardware

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 - Software

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. 

Testing

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 A test plan should be designed before testing

commences.

Part of system tested Purpose Expected result Actual result

Members File Add new memberNew member on members list

New member appeared

Members File Remove a memberMember not on membership list

Member deleted from list

ImplementationImplementing or introducing a new system can be done

in two ways: 

Direct Implementation Parallel Running

Implementation - Direct

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 - Parallel Running

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. 

Documentation

A number of documents are produced during the development of a new computer application. Essentially there are two types: 

User GuidesTechnical Documentation

Documentation - User Guides

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 - Technical

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.

The End

Prepared by:Arjaa Salem Makkawi

ID: 10120054Sec : 2