The systems life cycle: implementation Cambridge IGCSE Information & Communication Technology revision
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In plain words
The new system works. Now the organisation has to move over to it, and there are four ways of doing that. They differ in risk, in cost and in how long they take.
4 things to know
- Direct changeover: the old system stops and the new one starts at once. It is the fastest and cheapest, and benefits come immediately. But if the new system fails there is nothing to fall back on, and data can be lost.
- Parallel running: both systems run together for a time. If the new one fails, the old one is still there, and results can be compared. But the work is done twice, so it costs more in time and staff.
- Pilot running: the new system is brought in at one branch or department first. If it fails, only one part of the organisation is affected, and lessons are learned before the rest change. But it takes longer for everyone to have the new system.
- Phased implementation: the new system is brought in one part at a time. If a part fails, only that part is affected, and staff can be trained gradually. But it takes a long time, and the two systems have to work together meanwhile.
Worked example
A hospital is replacing the system that holds its patient records. Which method of implementation should it choose?
- Losing access to patient records could be dangerous, so the risk must be as low as possible.
- Parallel running keeps the old system working until the new one has been shown to be reliable.
- The extra cost of running both is worth paying for the safety.
Tips and tricks
- Direct: quick but risky. Parallel: safe but costly. Pilot: one place first. Phased: one part first. Four words to hang each on.
- Pilot and phased are the two that get mixed up. Pilot is the whole system in one branch. Phased is one part of the system everywhere.
It lands in your notebook with its questions as flashcards.
The systems life cycle: implementation: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Which method stops the old system and starts the new one at the same moment?
There is no overlap.
Which method runs the old and new systems together for a time?
The old system is a backup.
Which is the main disadvantage of direct changeover?
It is the riskiest method.
A chain of shops introduces a new till system in one shop before the others. This is:
The whole system, in one location first.
Which is a disadvantage of parallel running?
Staff have to enter everything twice.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
2 questions, 6 marks. Write your answers on paper, then check them.
The systems life cycle: implementation
Cambridge IGCSE Information & Communication Technology 0417 · 6 marks · papermunch.org
Name ______________________________ Date ______________
Give one advantage and one disadvantage of direct changeover, and one advantage and one disadvantage of parallel running.[4]
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Direct changeover: the benefits are immediate and it is cheap, but if the new system fails there is no backup. Parallel running: the old system is available if the new one fails, but it is expensive because the work is done twice.
Describe pilot running.[2]
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The new system is introduced in one branch or department of the organisation first. It is extended to the others once it is working well.
Answers: The systems life cycle: implementation
- 1. Direct changeover: the benefits are immediate and it is cheap, but if the new system fails there is no backup. Parallel running: the old system is available if the new one fails, but it is expensive because the work is done twice.
- 2. The new system is introduced in one branch or department of the organisation first. It is extended to the others once it is working well.