Conversion or changeover from old or manual system to the new system requires careful planning to establish the sustainable change. There is no single best way to proceed with conversion. It may be noted that adequate planning and scheduling of conversion as well as adequate security are more important for a successful changeover.
There are five strategies for conversion from old system to new system.
• Direct Changeover
• Parallel Conversion
• Gradual Conversion
• Modular Prototype Conversion
• Distributed Conversion
Conversion direct changeover means that on a specified date the old system is dropped and the new system is put into use. Direct changeover can only be successful if extensive testing is done beforehand. An advantage of the direct changeover is that users have no possibility of using the old system other than the new.
This refers to running the old system and the new system at the same time, in parallel. This is the most frequently used conversion approach but its popularity may be in decline because it works best when a computerized system replaces a manual one. Both systems are run simultaneously for a specified period of time and the reliability of results is examined. When the same results are gained over time, the new system is put into use and the old one is stopped.
Gradual conversion attempts to combine the best features of both direct changeover and parallel conversion without incurring the risks. In this plan the volume of transactions is gradually increased as the system is phased in.
Modular Prototype Conversion:
This approach to conversion uses the building of modular, operational prototypes to change from old system to new in a gradual manner. As each module is modified and accepted, it is put into use.
This refers to a situation in which many installations of the same systems are contemplated such as in banking or in franchises such as restaurants or clothing stores. One entire conversion is done at one site. When that conversion is successfully completed other conversion are done for other sites