5.1 The Task Model of Software

5.1.1 Modeling – What and Why

This opening section might, at first, seem to be somewhat academic, far removed from the reality of software and software engineering. Not so. It does, in fact, deal with a very practical and important topic: the use of models as part of the design process. However, before going further, we need to answer two key questions:

1. What is a model?
2. Why do we use models?

A model, in our view, is a "representation of reality." Although that sounds pretty abstract (and not especially helpful), it actually gets to the heart of the matter. Now, let's make it more meaningful by looking at some tangible items (Figures 5.1, 5.2, and 5.3):

Figure 5.1: Clay model of a car

Figure 5.2: Functional scale model of a marine craft

Figure 5.3: Block diagram model of a microcomputer

In the auto industry, it is common practice to produce...