Objectives: Introduction Over View of System Analysis and Design
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- 8.3.1 Maintenance Issues
| 8.3 Maintenance of Systems When systems are installed, they generally are used for long periods. The average life of a system is 4 to 6 years, with the oldest application often in use for over 10 years. However, this period of use brings with it the need to continually maintain the system. Because of the use a system receives after it is fully implemented, analysts must take precautions to ensure that the need for maintenance is controlled through design and testing and the ability to perform it is provided through proper design practices. 8.3.1 Maintenance Issues Many private, university and government studies have been conducted to learn about maintenance requirements for information systems. The studies have generally concluded the following 1. From 60 to 90 percent of the overall cost of software during the life of a system is spent on maintenance. 2. Often maintenance is not done very efficiently. In documented cases, the cost of maintenance, when measured on the basis of the cost of writing each instruction in code form, is more than 50 times the cost of developing a system in the first place. 3. Software demand is growing at a faster rate than supply. Many programmers are spending more time on systems maintenance than on new development. Studies have documented that in some sites, two – thirds of the programmes are spending their time on the maintenance of software. There is a backlog of new development work. Moreover, there is a hidden backlog, requests for development work that users do not bother even to submit because they know it will be years before development can being. Several studies of maintenance have examined the type of tasks performed under maintenance. The broad classes maintenance found in information systems environments are corrective, adaptive and perfective. Once systems are installed, the need for debugging and correcting errors or failures on an emergency basis is comparatively low less than 20 percent of the tasks are for correction. Information systems and the organizations they serve are in a constant state flux. Therefore, the maintenance of systems also involves adaptations of earlier versions of the software. Approximately 20 percent of all maintenance is performed to accommodate changes in reports, files and data. This also includes adaptations required when new hardware or software is installed in a particular processing center. The greatest amount of maintenance work is for user enhancement, improved documentation, or recoding systems components for greater efficiency. Sixty percent of all maintenance is for this purpose. Yet, many of the tasks in this category can be avoided if systems engineering is carried out properly. Download 0.94 Mb. Share with your friends:
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