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Scheme of work – Cambridge IGCSE® Computer Studies (0420)
Unit 3: System life cycle
Recommended prior knowledge
It would be helpful if students had studied Unit 1 before starting this unit.
Context
Students need to study this unit before Units 4 and 5 and relevant sections of it before or alongside the corresponding sections of Unit 12. For this unit, Computer
Studies Support Booklet - Part 2 (http://teachers.cie.org.uk/docs/dynamic/31797.pdf) provides notes on section 2 of the syllabus and practice problems (with
answers in Computer Studies Support Booklet - Answers (http://teachers.cie.org.uk/docs/dynamic/31801.pdf).
Outline
Principles of the system life cycle, including aspects of analysis (including fact finding methods and feasibility study), design, implementation (building), testing,
documentation, methods of changeover, evaluation and maintenance, including the use of system flowcharts and dataflow diagrams to describe existing and
proposed systems. This is achieved partly through the study of computer applications, in particular the methods by which a problem has been analysed to lead to a
successful solution for the user, and partly through practical work.
Syllabus
ref
Learning
objectives
2
Introduction
v1 2Y04
Suggested teaching activities
Learning resources
Students need to examine a variety of problems and their solutions, in
order to learn what is required at each stage of the system life cycle and
the appropriate types of diagram. A relatively simple problem would
enable students to focus on a feasibility study and analysis stage. For
example, how to replace a paper-based record of pocket money and
expenditure with a computerised solution, including:
1. Identifying and describing the problem (a spreadsheet to keep a check
on student’s pocket money, expenditure and possible savings).
2. Stating objectives (computerised system that is given data on income
and expenditure and automatically calculates the balance).
3. Identifying flows of data (with a dataflow diagram) and how data are
entered into system and processed to produce output on paper (with a
system flowchart).
4. Describing and evaluating the existing, paper-based solution (need to
calculate manually or use a calculator, which makes it difficult to use
LWS coursebook pp. 117–25
Cambridge IGCSE Computer Studies (0420)
CD of notes from the former website
www.theteacher99.btinternet.co.uk/theteacher includes a
basic introduction to the Analysis stage
www.teachict.com/gcse/theory/syslifecycle/student/shome_slc.htm
Theory notes, activities and quizzes – the first four
sections of the theory provide a more in-depth look
1
Syllabus
ref
2
Learning
objectives
Introduction (cont)
2.1.1
Fact finding
2.1.2
2.1.3
Feasibility study
Analysis
2.1.4
Design
Suggested teaching activities
“what if” scenarios for predictions, but is cheap and simple to use).
5. Describing and evaluating alternative solutions (e.g. off-the-shelf,
spreadsheet software to do the calculations automatically – would this
be an appropriate solution?).
More complex examples from commerce and industry would enable
students to progress to later stages. For example, how to replace a
paper-based stock control system in a supermarket with an automatic
system for calculating stock levels and automatically re-ordering,
including:
1. Analysis of old, paper-based system, with appropriate diagrams.
2. Design choice of hardware for reading barcodes, numbers of
checkouts required (using simulations of queues) and appropriate
software and processing, with appropriate diagrams.
3. Testing (types of data required).
4. Documentation (contents of user guide and technical documentation).
5. Changeover (pilot changeover probably best in this case study).
6. Evaluation (what needs to be evaluated and when).
7. Maintenance (possible types required).
Students need to identify the methods used in fact finding (and which
method is appropriate for an application).
Students need to identify what is involved in a feasibility study.
Students need to identify what is involved in the analysis stage and learn
to use appropriate diagrams, such as a dataflow diagram or system
flowchart.
Students need to:
• distinguish between design (detailed planning) and implementation
(building) – note that this distinction is blurred by the common practice
of referring to programs for building or authoring websites as “web
design” software
• learn that appropriate diagrams, such as a Gantt or PERT chart,
dataflow diagram, system flowchart, structure diagram for top-down
design or program flowchart form vital parts of solution planning and
design.
Learning resources
LWS coursebook pp. 117–45
www.teachict.com/gcse/theory/syslifecycle/student/shome_slc.htm
Theory notes, activities and quizzes – note that
Development is used here to mean building and
Implementation to mean changeover
LWS coursebook pp. 119–21
LWS coursebook pp. 121–2
LWS coursebook pp. 122–5
LWS coursebook pp. 122–34
http://open-workbench.en.softonic.com/
Open Workbench, free project management program for
Windows, enables students to get a feel for producing
project management diagrams such as Gantt charts and
PERT charts using software
http://igcsecs.blogspot.com/p/open-workbench_18.html
Has a link to a tutorial guide to Open Workbench that
should take you as far as you need for school projects
http://raptor.martincarlisle.com/
Free program flowchart interpreter software that allows
v1 2Y04
Cambridge IGCSE Computer Studies (0420)
2
Syllabus
ref
Learning
objectives
2.2.1
Implementation
2.2.2
Testing
2.2.3
Documentation
2.2.4
Changeover
2.2.5
2.2.6
Evaluation
Maintenance
v1 2Y04
Suggested teaching activities
Students need to identify what is involved in developing solutions using
off-the-shelf or bespoke software and appropriate hardware.
Students need to identify testing strategies and appropriate choice of test
data.
Students could sort a list of contents headings to distinguish between:
• documentation that users require in a user guide or manual and
• technical documentation required by those responsible for improving
and maintaining a solution in working order or for developing the
solution to meet new needs.
Students need to identify the available methods for changeover and their
benefits and drawbacks.
Students need to identify ways in which a system can be evaluated.
Students need to identify ways in which a system can be maintained.
Cambridge IGCSE Computer Studies (0420)
Learning resources
students to draw a flowchart and check its functioning by
executing it.
LWS coursebook p. 135
LWS coursebook pp. 135–6
LWS coursebook pp. 136–40
CD of notes from the former website
www.theteacher99.btinternet.co.uk/theteacher includes an
introduction to the different types of documentation
LWS coursebook pp. 140–3
LWS coursebook pp. 143–4
LWS coursebook pp. 144–5
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