Explain in detail the necessity and importance of System Design in MIS?

The Business application system demands designing of systems suitable to the application in project.

The major steps involved in the design are the following:

Input Design: Input design is defined as the input requirement specification as per a format required. Input design begins long before the data arrives at the device. The analyst will have to design source documents, input screens and methods and procedures for getting the data into the computer.

Output Design: The design of the output is based on the requirement of the user manager, customer etc. The output formats have to very friendly to the user. Therefore the designer has to ensure the appropriateness of the of the output format.

Development: When the design and its methodology are approved the system is developed using appropriate business models. The development has to be in accordance to a given standard. The norms have to be strictly adhered to.

Testing: Exhaustive and thorough testing must be conducted to ascertain whether the system produces the right results. Testing is time consuming: Test data must be carefully prepared, result reviewed and corrections made in the system. In some instances, parts of the system may have to be redesigned. Testing an information system can be broken down into three types of activities. Unit testing, system tests and acceptance testing.

Implementation and Maintenance : Conversion – Conversion is the process of changing from the old system to the new system. Four main conversion strategies can be employed.

They are – the parallel strategy, the direct cutover strategy, the pilot strategy and the phased strategy. In a parallel strategy both the old system and its potential replacement are run together for a time until everyone is assure that the new one functions correctly.

This is the safest conversion approach because, in the event of errors or processing disruption, the old system can still be used as a backup. But, this approach is very expensive, and additional staff or resources may be required to run the extra system. The direct cutover strategy replaces the old system entirely with the new system on an appointed day. At first glance, this strategy seems less costly than the parallel conversion strategy. But, it is a very risky approach that can potentially be more costly than parallel activities if serious problems with the new systems are found. There is no other system to fall back on. Dislocation, disruptions and the cost of corrections are enormous.

The pilot strategy introduces the new system to only a limited area of the organization, such as a single department or operating unit. When this version is complete and working smoothly, it is installed throughout the rest of the organization, either simultaneously or in stages. The phased strategy introduces the new system in stages, either by functions or by organizational units. If, for example, the system is introduced by functions, a new payroll system might begin with hourly workers who are paid weekly, followed six months later by adding salaried employees (who paid monthly) to the system. Maintenance is also necessary for other failures and problems that arise during the operation of a system. End-users and information systems personnel then perform a troubleshooting function to determine the causes of and solution to such problems.

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