List and describe the four main system changeover methods. Which one generally is the least expensive? Which is the safest? Explain your answers.
What will be an ideal response?
System changeover is the process of putting the new information system online and retiring the old system. It can be accomplished by any of the following four methods. Students can refer to Figure 11-30 for an overview. The methods are described as follows:
? Direct cutover. This method causes the changeover to occur immediately. It usually is the least expensive method because it involves the operation and maintenance of only one system at a time. It is the most risky of the changeover methods because old data will not be available should the system develop problems.
? Parallel operation. This method requires that both the old and new systems be run in parallel for a specific period of time. Users must work fully in both systems to reap the benefits of a parallel conversion. This method is more expensive but it is the least risky.
? Pilot operation. This method involves implementation of a new system at a beta or pilot test site. The majority of users continue to use the old system while a select group of users perform daily operations on the new system.
? Phased operation. This method allows the implementation of a new system to be done in stages or modules, rather than all at once. Related groups of users begin using the new system, while other users continue to use the old system until it is their turn to be phased in to the operations.
Parallel operation changeover methods generally tend to be the most expensive because a company is running two systems at the same time to accomplish the same tasks. This creates a doubling of time and materials for the users. Also, running both systems might place an extra burden on the hardware, which can cause processing delays. The direct cutover method of changeover generally is the most risky because this method cuts off the use of the old system when the new system is implemented.
Although any method of changeover involves a certain amount of risk, the direct cutover method can be the most costly because you cannot revert back to the old system if the new one fails.
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