The business application system demands designing of systems suitable to the application in project.
The major steps involved in the system design of Management Information Systems(MIS) 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 output format.
Development — When the design and its methodology is 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, results 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 testing and acceptance testing. Unit testing or program testing consists of testing each program separately in the system. The purpose of such testing is to guarantee that programs are error free, but this goal is realistically impossible. Instead, testing should be viewed as a means of locating errors in programs, focusing on finding all ways to make a program fail. Once pinpointed, problems can be corrected. System testing tests the functioning of the information system as a whole. It tries to determine if discrete modules will function together as planned and whether discrepancies exist between the way the system actually works and the way it was conceived. Among the areas examined are performance time, capacity for file storage and handling peak loads, recovery and restart capabilities and manual procedures. Acceptance testing provides the final certification that the system is ready to be used in a production setting. Systems tests are evaluated by users and reviewed by management. When all parties are satisfied that the new system meets their standards, the system is formally accepted for installation.
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 disruptions, 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 system are found. There is no other system to fall back on. Dislocations, disruptions and the cost of corrections are enormous.
- The pilot study 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 approach 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 are paid monthly) to the system. If the system is introduced by organizational units, corporate headquarters might be converted first, followed by outlying operating units four months later.
Moving from an old system to a new system requires that end users be trained to use the new system. Detailed documentation showing how the system works from both a technical and enduser standpoint is finalized during conversion time for use in training and everyday operations. Lack of proper training and documentation contributes to system failure, so this portion of the systems development process is very important.
Production and maintenance
After the new system is installed and conversion is complete, the system is said to be in production. During this stage the system will be reviewed by both users and technical specialists to determine how well it has met its original objectives and to decide whether any revisions or modifications are in order. In some instances, a formal post implementation audit document will be prepared. After the system has been finetuned, it will need to be maintained while it is in production to correct errors, meet requirements or improve processing efficiency.
Once a system is fully implemented and is being used in business operations, the maintenance function begins. Systems maintenance is the monitoring, or necessary improvements. For example, the implementation of a new system usually results in the phenomenon known as the learning curve. Personnel who operate and use the system will make mistake simply because they are familiar with it. Though such errors usually diminish as experience is gained with a new system, they do point out areas where a system may be improved.
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 solutions to such problems. Maintenance also includes making modifications to an established system due to changes in the business organizations, and new e-business and ecommerce initiatives may require major changes to current business systems.