CSE1IS Information Systems Week 12 Lecture 2 Systems Support and Maintenance

S.C.&R. Chapter 10, pp. 474-493

Once a new system is operational then it is advisable to carry some form of post-implementation review. This involves an evaluation of the end-product i.e. the system and also the process by which it was developed. You would seek feedback in the following areas when evaluating the product.

• user satisfaction
• system reliability and efficiency
• effectiveness of security features
• accuracy of system output
• quality and effectiveness of training
• quality and usefulness of system/user documentation

When evaluating the process of development you would interested in
the performance of the project team

• accuracy of cost-benefit analysis
• effectiveness of project management i.e. schedules, allocation of resources, maintenance of standards
• quality of  project documentation (e.g. requirements document, preliminary investigation report etc.)

On-going system maintenance may be required. Figure 10-7 on p.477 of the text shows how maintenance costs vay over time. Broadly speaking three types of maintenance activities can be identified.

• corrective maintenance
• adaptive maintenance
• perfective maintenance
• preventative maintenance

Corrective Maintenance involves the detection and correction of errors that only become apparent during system operation. These errors may arise because of minor changes made to the system after implementation or they may have been undetected during system testing (i.e. before implementation). You would hope that corrective maintenance on a newly implemented system would be minimal --- otherwise you would need to re-examine your testing strategies and plans ( as part of the post-implementation review).

Adaptive maintenance involves the addition of new features (or the modification of existing features) to an operational system. This may arise because the business operations of an organization change and the IS supporting these operations may need to be modified accordingly. The scale of change will vary. If the proposed changes are significant then a formal SDLC approach may be necessary. That is why the SDLC is called a system development lifecyle.

Perfective maintenance involves the modification of a system to make it more efficient, reliable and maintainable. This may include the replacement of hardware components (e.g. cabling, memory, CD-ROM drives) as well as modifications to the software modules.  For example you may wish to reduce processing time, increase the effectiveness of the user interface and reduce the development time for future software. All of these would be classed as objectives for perfective maintenance.

Preventative maintenance involves analysis of areas where trouble is likely to occur and thus avoids future problems.

In some ways the maintenance tasks in IS are analogous to those performed on an automobile. Tuning an automobile to enhance performance is  perfective maintenance, the replacement of a defective battery is similar to corrective maintenance, the fitting of fog lamps might be interpreted as adaptive maintenance and checking the oil level regularly is preventative maintenance.

Examples of the four types of maintenance tasks are shown in Figure 10-8 of the text:

References:

• Shelly, Cashman & Rosenblatt, Systems Analysis and Design, 6th Edition,  Course Technology, 2006.

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