It could be argued that information systems are vital components of any civilisation. The human desire to record information goes back thousands of years to when humans first started painting on stones. However, it is the practice of recording and displaying information in a systematic manner that warrants the use of the term “information system”. Such practices can be easily found in great civilisations, such as those of ancient Egypt, Greece and Rome.

The development and use of information technology (IT) has led to the birth of new generations of information systems. Computer-based information systems (software systems) have dramatically influenced our behaviour and the way in which we conduct every day activity. It is not surprising that the standing of any society in the world is now strongly linked to the level of penetration that software systems have in that society.

In this module we shall use term software systems to refer to information systems that contain or might contain software components. Although there are many information systems that do not involve computers, such as a card filing system of a small library or a manager's list of contacts, almost all modern information systems either use computers, or could use computers, to perform some of their functions (such as cash registers for point-of-sales processing, and stock control systems for small businesses).

Further, while we will occasionally mention information systems, this module is ultimately interested in the software components of an information system, and how to engineer software that can be reliably used by other people. Software is integral to computerised information systems. Without the underlying software, the system will not be able to do what its users intend, and if the software functions incorrectly, so will the information system.