August 1997 SD206: Systems Design (Question 1) Suggested Solutions

1.	(a) List two criteria that should be considered when selecting an output method.		[2]
	One mark (up to a maximum of two marks) should be awarded for each correct criterion named. Examples include the following:
		Budget.
		Maintenance cost.
		Software compatibility.
		Vendor support.

	(b) List two structured tools used in system or program design.		[2]
	One mark (up to a maximum of two marks) should be awarded for each correct method named. Examples include the following:
		SSADM.
		YOURDON.
		HIPO.
		Warnier/Orr.
		Nassi-Schneidermann.
		SADT.

	(c) List four forms of control.		[4]
	One mark (up to a maximum of four marks) should be awarded for each correct form named. Examples include the following:
		Access control.
		Source document control.
		Data entry control.
		Processing control.
		Communication control.
		Audit trail.
		Output control.
		File control.
		Documentation control.
		Software control.
		Organisational control.

	(d) How may we differentiate between a toolbar and index help?		[2]
	A toolbar is a group of icons arranged in a bar form that arrange such functions as pointing, cropping, drawing, etc.,		[1]
	whereas index help is a system function that uses indices to allow users to quickly pinpoint the required help.		[1]
	Marks should also be awarded for other sensible answers.

	(e) How may we differentiate between logical and physical data flow diagrams?		[2]
	*Logical data flow diagrams concentrate on what* processing should be done and highlight data items used within the system,**		[1]
	*whereas physical data flow diagrams concentrate on how* the processing should be done and deal with the ways in which data items are contained or represented in the data flow diagrams.**		[1]
	Marks should also be awarded for other sensible answers.

	(f) How may we differentiate between batch processing and on-line processing?		[2]
	Batch processing involve processing transactions periodically,		[1]
	whereas on-line processing involves processing transactions when a transaction occurs.		[1]
	Marks should be awarded for other sensible answers.

	(g) Give an example of a mnemonic instruction and an example of an annotated instruction.		[2]
	One mark should be awarded for a correct example of a mnemonic instruction and one mark should be awarded for a correct example of an annotated instruction. A typical mnemonic instruction is
		DD/MM/YY
	whereas a typical annotated instruction is
		Morning/Afternoon/Evening* *please delete appropriately

	(h)	What is the Check-digit for customer number 29645	[4]
		(i) using a '3-1-3' weighting and a modulus 10 system?
		8	[2]
		(ii) using a '2-1-2' weighting and a modulus 10 system?
		1	[2]