3.4 Practical Approaches to Analysis and Specification

3.4.1 General Aspects

What is the fundamental purpose of the analysis and specification – the requirements – phase? It is to define what a proposed system is to do, not how it is supposed to do it; "how" is the function of the design process. However, in practice, there isn't always a sharp boundary between requirements and design. And the problem is compounded because some design methods make little distinction between the two. We can see why these overlap by considering the make-up of the requirements stage (Figure 3.15). The first part of this process is concerned with analyzing and recording the system requirements. Note this well. Many traditional (that is DP) descriptions discuss the analysis of systems, but you can only analyze a system if one already exists.

In the initial run-through, design factors shouldn't affect the outcome of the analysis work. Using the information acquired...