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(a)List the six steps which are necessary
for deriving a structure chart from a leveled set of data flow diagrams.[6
marks ]
One mark should
be awarded for each step named. The steps are:
• Perform transaction analysis.
• Determine the central transform.
• Produce a first-cut structure chart.
• Add modules and show data flows.
• Write module details.
• Conduct software design walk-through. [6 marks ]
(b)Explain how internal receivers differ
from external receivers.... [2marks ]
Internal receivers belong to the organisation —they are part
of the system —(1 mark), whereas external receivers do not belong
to the organisation (1 mark). Other valid answers should also receive
credit. [2 marks ]
(c)List two visible costs of paper forms.[2
marks ]
One mark should
be awarded for each cost named (up to a maximum of two marks).
Examples include the following:
• Pape costs.
• Typesetting costs.
• A twork costs.
• Printing costs. Other valid answers should also receive credit.
[2 marks ]
(d)Define the term direct manipulation
interface.... [2marks ]
Direct manipulation
interfaces graphically supply the user with a strong metaphor of the
application (1 mark).They allow direct manipulation of the graphical
representation of the screen via input devices (1 mark). Other valid
answers should also receive credit. [2 marks ]
(e)List two factor that may assist in
ensuring a high quality of data capture. [2 marks ]
One mark should be awarded for each valid point (up to a maximum of
two marks). Examples include the following:
• Effective coding.
• Effective and efficient data capture and entry.
• Assuring data quality through validation. Other valid answers
should also receive credit. [2 marks ]
(f)Describe the following types of controls
(i)Processing controls.[2 marks ]
Processing
controls are incorporated within individual application programs (1
mark), and are designed to assure the accuracy and completeness of
records each time a file is processed (1 mark). Other valid answers
should also receive credit. [2 marks ]
(ii)Audit trails.[2 marks ]
An audit trail is a series of records (1 mark) that can be used for
tracking data through a system from the time a transaction originates
to the point when the data is incorporated into master files or summary
statistics (1 mark). Other valid answers should also receive credit.
[2 marks ]
(g)(i)Why should analysts acknowledge
that it is impossible to totally avoid
errors?[1 mark ]
Because
errors will always occur, despite everyone ’s best intentions.
Other valid answers should also receive credit. [1 mark]
(ii)What is error detection
and correction [2marks ]
Error detection and correction uses design features to detect errors
and make necessary changes to either correct the error or its effect
on the user (1 mark), so that a failure does not occur (1 mark). Other
valid answers should also receive credit. [2 marks ]
(iii)What is error tolerance [1mark ]
Error tolerance is the technique of keeping a system running in the
presence of errors. Other valid answers should also receive credit.
[1 mark ]
(h)(i)When do organisations get the most
benefit from CASE technology?[1 mark ]
When they
use a set of well-integrated CASE tools that automate and support
an integrated software life cycle process. Other valid answers should
also receive credit. [1 mark ]
(ii)Why should selecting
a methodology be the first step in implementing
CASE?[1 mark ]
Because a structured development methodology provides the overall
framework for defining and linking together the software process steps.
Other valid answers should also receive credit. [1 mark ]
(i)(i)What is modular conversion [1mark
]
Modular conversion is the implementation of a system on a piecemeal
basis. Other valid answers should also receive credit. [1 mark ]
(ii)Give two disadvantages
of modular conversion.[2 marks ]
One mark should be awarded for each disadvantage named (up to a maximum
of two marks). Examples include the following:
• The conversion period may be very long.
• The approach is not feasible fo every situation.
Other valid answers should also receive credit. [2 marks ]
(iii)How does phase-in
conversion differ from modular conversion?[1 mark ]
The phase-in approach involves the system being segmented, rathe rthan
the organisation. Other valid answers should also receive credit.
[1 mark ]
(iv)Give two advantages
of phase-in conversion.[2 marks ]
One mark should be awarded for each advantage named (up to a maximum
of two marks). Examples include the following:
• The rate of change in a given organisation can be minimised.
• Data processing resources can be acquired over an extended
period of time. Other valid answers should also receive credit. [2
marks ]
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