System Implementation is an important aspect of a systems analyst’s job is to make sure that the new design is implemented to established standards. The term implementation has different meanings, ranging from the conversion of a basic application to a complete replacement of a computer system. The procedure is virtually the same. Implementation is used here to mean the process of converting a new or a revised design into an operational one. Conversion is one aspect of implementation. The other aspects are the post implementation review and software maintenance.
There are three types of implementations:
- Implementation of a computer system to replace a manual system. The problems encountered are converting files, training users, creating accurate files, and verifying printouts for integrity.
- Implementation of a new computer system to replace an existing system. This is usually a difficult conversion. If not properly planned, there can be many problems. Some large computer systems have taken as long as a year to con-vert.
- Implementation of a modified application to replace an existing system using the same computer. This type of conversion is relatively easy to handle, provided there are no major changes in the files.
Once all the preparatory work of implementation has taken place. The system has been tested and the staff trained, the change over from the old to the new system can begin. This involves activities like conversion of old files to the new format, converted files need to be setup on the computer and old procedures to be replaced by new ones. The changeover may be achieved in a number of ways. The most common methods are direct changeover, parallel running, pilot running and staged changeover.
As this term implies, this method is the complete replacement of the old system by the new in one go. It is a bold move, which should be undertaken only when everyone concerned has confidence in the new system.
Parallel running or operation means processing current data both by the old and new systems to cross check the results. Its main attraction is that the old system kept alive and operational until the new system has been proved for at least for one system cycle, using full live data in the real operational environment of place, people, equipment and time. It allows the result of the new system to be compared with the old system before acceptance by the user, thereby promoting user confidence. Its main disadvantage is the extra cost, the difficulty and the impracticability of user staff having to carry out the different clerical operations for two systems in the time available for one and then cross checking the results, including error handling, at a time when staff are fully occupied with the new procedures.
Pilot running is similar in concept to parallel running. Data from one or more previous periods for the whole or part of the system is run on the new system after results have been obtained from the old system, and the new results are compared with the old. It is not as disruptive as parallel operation, since timing is less. critical. However,. the users still have to cope with the clerical procedures for both the old and new systems.
A staged changeover involves a series of limits size direct changeovers, the new system being introduced piece-by-piece. A complete part, or logical section, is committed to the new system while the remaining parts or sections are processed by the old system. Only when the selected part is operating satisfactory is the remainder transferred.