Why is a system maintained after delivery, and what kinds of maintenance are there?
The purpose of system maintenance and the three types of maintenance (corrective, adaptive and perfective), with examples of each.
A CCEA A-Level Digital Technology answer on system maintenance: why systems are maintained after delivery and the three types of maintenance, corrective, adaptive and perfective, with examples of each.
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What this dot point is asking
CCEA wants you to explain why a system is maintained after it goes live and to describe the three types of maintenance, corrective, adaptive and perfective, with examples. Maintenance is the final stage of the life cycle, and it is where most of a system's lifetime cost is spent.
Why systems are maintained
A system does not stop changing at delivery. Faults still surface on real data, the world around the system changes (new operating systems, new hardware, new legislation), and users think of improvements once they have used it. Each of these triggers a small, fresh pass through analysis, design, implementation and testing, which is why the life cycle is iterative rather than ending at installation.
The three types of maintenance
- Corrective maintenance. Fixing faults (bugs) discovered after the system is live, for example correcting a formula that totals a column incorrectly.
- Adaptive maintenance. Changing the system to keep it working in a new environment, for example updating it for a new operating system, new hardware, or a change in the law such as a new VAT rate.
- Perfective maintenance. Enhancing or improving the system even though nothing is broken, for example adding a new report, improving the layout of a screen, or speeding up a slow query.
Why maintenance dominates lifetime cost
Because a system is in use for years, the cumulative cost of fixing faults, adapting to a changing environment and adding improvements typically exceeds the cost of building it in the first place. Each change repeats life-cycle work, analyse, design, implement, retest, and is often done by staff who did not build the original system, which is exactly why thorough technical documentation pays for itself.
Try this
Q1. Name the type of maintenance that fixes a fault found after the system goes live. [1 mark]
- Cue. Corrective maintenance.
Q2. Give one example of adaptive maintenance. [1 mark]
- Cue. Updating the system to run on a new operating system, new hardware, or to comply with a new law.
Q3. Explain why perfective maintenance is still carried out on a system that has no faults. [2 marks]
- Cue. Users request enhancements and new features, and improving performance or usability keeps the system valuable, so changes are made to improve a working system even when nothing is broken.
Exam-style practice questions
Practice questions written in the style of CCEA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
CCEA AS 16 marksDescribe the three types of system maintenance, giving an example of each.Show worked answer →
Name all three types and pair each with a clear example.
Corrective maintenance fixes faults (bugs) found after the system is live, for example correcting a calculation that produces the wrong total. Adaptive maintenance changes the system to keep it working in a changed environment, for example updating it to run on a new operating system or to comply with a new tax rate set by law. Perfective maintenance improves or enhances the system, for example adding a new report or making a screen faster or easier to use, even though nothing was broken.
Markers award marks for each type correctly named and described, and for an example that genuinely fits that type. The common error is confusing adaptive (responding to an external change) with perfective (a chosen improvement); the examiner checks the example matches the type.
CCEA AS 14 marksExplain why maintenance accounts for a large part of the total cost of a system over its lifetime.Show worked answer →
Link the long operational life of a system to the ongoing need for all three maintenance types.
A system is in use for many years, far longer than it took to build. Over that time faults are still found and must be corrected (corrective), the environment changes (new hardware, software or laws) and the system must adapt (adaptive), and users request improvements and new features (perfective). Each change needs analysis, design, implementation and retesting, sometimes by staff who did not build the original system, which is why good documentation matters. Together these ongoing activities can cost more than the original development.
Markers reward the points that the operational life is long, that all three maintenance types continue throughout it, and that each change repeats life-cycle work, making the cumulative cost large.
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Sources & how we know this
- CCEA GCE Digital Technology specification — CCEA (2016)