the implemntation phase developing an implementation schedule,”Once all of the clients of the new system are in place. The next step is to develop the implementttion schedule (or cutover) and family to cut over to the new system. Most systems have a staggered introduction. That is elements of the system are introduced one at a time and so that it is possible to ensure that they are working as intended before the next element is introduced. This is a common approach as it allows the developers to quickly isolate problems in individual sectors of the system. If more than one element of the system is introduced at the time to isolate where the problem is occurring. This staggered introduction is commonly refereed to as a “”cutover”” this is because the two system cut over one another as each element is introduced. This is by far the most preffered method of introducing a new computer system however there are times when it is not possible to do this. Where the ability to introduce the system in sectors is not available, for example the new system is not compatible with existing equipment, which will be dispoed of when the new system is commissioned- a different implementation method must be used. Most commonly, it will be one that involves the use of parallel systems. As the name suggests, a parallel system is where two systems (the current and the new ones) are being run at the same time to perform the same job. While this duplicates the work there are some significant advantages to this type of system. As the performance of the existing system is a known quality, it gives us something to compare the performance and accuracy of the new system to. Often parallel systems will operate for a month or two before the old system is decommissioned. The biggest problem with parallel system is that the duplication of the work can be costly however this must be viewed against the security of the knowledge that if the new ssystm under performs, the old system can be kept operating until such time as all problems with the new system are sorted out. Where the new system requires the old hardware and/or software to be removed and it is not possible to have a cutover program or parallel systems, the only option available is the use of a trial system. This where a small version of the system is set up and tried before the widespread intoruction of the system. The trial emulates all aspects of the computer system to ensure that it will work properly. It aims to reproduce as closely as possible the “”real life”” situation the system will be used in> If the system is to be used in a number of locations often this trial will occur in a single location which crosses over to the new system and evaluates its performance until its is satisfactory
at which time is is then introduced to the rest of the company.”