ZIMSEC O Level · Computer Science · Form 3, Form 4
The systems development life cycle
- Analysis: study the current system (interviews, questionnaires, observation) and identify requirements.
- Design: plan inputs, outputs, files, data structures and user interfaces.
- Development and testing: write the programs and test with normal, boundary (extreme) and erroneous data.
- Implementation: change over by direct, parallel, phased or pilot methods.
- Documentation: user guides and technical documentation.
- Evaluation and maintenance.
Changeover methods
- Direct: switch at once – quick but risky.
- Parallel: run old and new together – safe but costly.
- Phased: introduce part by part. Pilot: try in one branch first.
ICT in society
- Education (online learning such as ZIMFundi), health (records, telemedicine), banking (mobile money, internet banking), agriculture (weather alerts, market prices), government (online services, e-tax filing with ZIMRA).
- Benefits: speed, accuracy, access to information. Problems: job losses, the digital divide between urban and rural areas, privacy risks and cybercrime.
Exam tip: Test data questions: “normal” is valid and typical, “boundary” is at the limits, “erroneous” should be rejected.
Check yourself
- Name the stage where interviews and questionnaires are used.
- Give one advantage and one disadvantage of parallel changeover.
- For a mark from 0 to 100, give one boundary and one erroneous test value.
Show answers
- Analysis.
- Advantage: safe, old system available if new fails. Disadvantage: expensive, double work.
- Boundary: 0 or 100. Erroneous: −5, 150 or "abc".
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