Introduction  (Page 2/8)

We have made tremendous progress since 1968 and that the development of software engineering has markedly improved our software. We have a much better understanding of the activities involved in software development. We have developed effective methods of software specification, design and implementation. New notations and tools reduce the effort required to produce large and complex systems.

Software engineers can be rightly proud of their achievements. Without complex software we would not have explored space, would not have the Internet and modern telecommunications, and all forms of travel would be more dangerous and expensive. Software engineering has contributed a great deal in its short lifetime and I am convinced that, as the discipline matures, its contributions in the 21st century will be even greater.

What is software?

Many people equate the term software with computer programs. In fact, this is too restrictive a view. Software is not just the programs but also all associated documentation and configuration data which is needed to make these programs operate correctly. A software system usually consists of a number of separate programs, configuration files which are used to set up these programs, system documentation which describes the structure of the system and user documentation which explains how to use the system and, for software products, web sites for users to download recent product information.

Software engineers are concerned with developing software products i.e. software which can be sold to a customer. There are two types of software product:

1. Generic products: These are stand-alone systems which are produced by a development organisation and sold on the open market to any customer who is able to buy them. Sometimes they are referred to as shrink-wrapped software. Examples of this type of product include databases, word processors, drawing packages and project management tools.

2. Bespoke (or customised) products: These are systems which are commissioned by a particular customer. The software is developed specially for that customer by a software contractor. Examples of this type of software include control systems for electronic devices, systems written to support a particular business process and air traffic control systems.

An important difference between these different types of software is that, in generic products, the organisation which develops the software controls the software specification. For custom products, the specification is usually developed and controlled by the organisation who are buying the software. The software developers must work to that specification.

What is software engineering?

Software engineering is an engineering discipline which is concerned with all aspects of software production from the early stages of system specification through to maintaining the system after it has gone into use. In this definition, there are two key phrases:

1. Engineering discipline: Engineers make things work. They apply theories, methods and tools where these are appropriate but they use them selectively and always try to discover solutions to problems even when there are no applicable theories and methods to support them. Engineers also recognise that they must work to organisational and financial constraints so they look for solutions within these constraints.