Software Design 2e - DIM

At a technical level, in terms of the strategies involved in their use, these methodsdiffer quite considerably, according to their domain of application. In that sense, therefore,we can regard the ‘organizational’ category as being essentially independent ofstrategy, so that a method can be both top-down and organizational, or compositionaland organizational.SummaryThis chapter has provided the basic material needed for the study of a number of designmethods in greater detail. In particular, it has outlined the forms of the principal technical strategiesthat are currently used in software design methods, and has examined some additional waysin which the attributes of a design method can be classified and its processes can be modelled.211Further readingFrom this, it can be seen that the major division in terms of design strategy lies between thenntop-down, or decompositional strategy; and thecompositional strategyand that design methods can further be classified according to whether they consider the effectsofnorganizational structures and rationale.Having examined the conditions for classifying software design methods in this manner, the followingchapters are concerned with describing and assessing a number of widely used designmethods, relating them to these issues in each case.Further readingWirth N. (1971). Program development by stepwise refinement. Comm. ACM, 14(4), 221–7This can be considered one of the classic papers in the area of software design. It is primarilyconcerned with the use of the top-down strategy for detailed program design, and is basedaround a worked example.Parnas D.L. (1972). On the criteria to be used in decomposing systems into modules. Comm.ACM, 15(12),1053–8This too is considered a classic paper in terms of its influence on software design (and the designof programming languages). It introduces the concept of information-hiding through the use ofa worked example, before proceeding to discuss the consequences of such a strategy for designpractices.