Software Engineering for Students A Programming Approach

2.4 Methodology 27
reality. Like any model, a model is only an approximation of reality. A process model
has two distinct uses:
■ it can be used as a basis for the plan for a project. Here the aim is to predict what
will be done.
■ it can be used to analyze what actually happens during a project. Here the aim is to
improve the process for the current and for future projects.
There are several mainstream process models:
■ waterfall
■ prototyping
■ incremental
■ agile
■ rational
■ open source
■ seat of the pants, do it yourself or ad hoc.
Each of these approaches will be discussed later in this book, except for the last in
the list. An ad hoc approach is no plan at all, and no organization would admit to using
such an approach. A software development project can take several years and involve
tens or even hundreds of people. Moreover, software development is a complex task.
To avoid catastrophe, some way of organizing a project must be established. Thus most
approaches identify a series of distinct stages within a project, along with a plan of what
order they will occur in.
2.4 ● Methodology
In common language, the word methodology means the study of method. It answers
such questions as: What is the basis of method x? How good is method y? However, in
software development, the term methodology has been kidnapped and come to mean
a complete package of techniques, tools and notations. Such a package is given a name,
say the XYZ methodology, and is often marketed by a corporation, together with
books, manuals and training. Consultants are also on hand to guide an organization in
using the methodology.
In this book, we have avoided describing any particular methodology, but we do
explain all the ingredients that go into making the mainstream methodologies available
today.