Aug 1999 SD206 : Systems Design (Question 4) Suggested Solutions

(a)	In the context of CASE, describe each of the following terms: (i) Front-end tools. (ii) Back-end tools. (iii) Integrated tools.	[2] [2] [2]
	(i) Front-end tools automate the early activities in the system development life cycle. Among the concerns of such tools is the development and analysis of requirements and specifications. (ii) Back-end tools assist in the formulation of such things as algorithms and device interaction. These tools help in converting designs into implementations. (iii) Integrated tools are concerned with the whole development cycle. In addition to front-end and back-end capabilities, such tools facilitate design, management and maintenance.
(b)	What are the differences between high-level and low level specifications?	[2]
	High-level specifications describe user requirements associated with input, output, and system performance, whereas low-level specifications are concerned with how input, output, and performance requirements may be met from the computing viewpoint.
(c)	(i) CASE tools provide facilities for error checking. List two types of error checking for diagramming system specifications. (ii) As well as error checking, interactive diagramming offers a number of advantages. Name two such advantages.	[2] [2]
	(i) Syntax and type checks. Completeness and consistency checks. Functional and decomposition checks. Cross-checking across all levels and views. Requirements traceability checks. (ii) It speeds up the development process. It enforces standardised representations of program and data structures.
(d)	(i) In the context of CASE, what is an information repository? (ii) Give two reasons why an information repository is a broader concept than a data dictionary.	[2] [2]
	(i) An information repository is a mechanism for storing and organising the information associated with the system. Such information includes that associated with planning, analysis, design, and implementation. (ii) An information repository stores more types information than a data dictionary. An information repository concerns itself with the relationships which exists between information components. An information repository concerns itself with rules for processing information components.
(e)	Give four reasons why the use of CASE technology does not always guarantee success.	[4]
	Many developers have not been trained in, or do not use, engineering-type development methodologies. CASE technology is not a substitute for good project management. The attitude of developers can have a major effect on the successful use of CASE technology. Software projects are often out of control because management does not enforce development standards and procedures.