6.1 Introduction

Legacy systems are computer systems, situated within a particular organizational environment, which no longer meet the needs of that environment. Such systems can cause considerable problems in organizations, from high-profile cases such as the millennium bug to less widespread but equally serious cases where, for example, companies have been unable to adapt their computer systems sufficiently to support their customer base or changing product profiles. Not all legacy is bad, however. Many legacy systems contain a massive amount of historical organizational data, business process information and/or functionality. Yet these systems are often inflexible or run on outdated hardware or software technology of which few people may have knowledge.

In this sense, then, they can become a liability rather than an asset. Even so, the term legacy systems has been overused and abused. A cynical view might suggest that the term is little more than an artefact of late capitalism, intended to make established usable software look outdated and sell more products. However, this view is also rather narrow. To summarize, a more holistic view of legacy systems would seem to suggest that the problem is the gap between the capabilities of the system and the needs of the business in which it is used (Brooke, 1994).

It is not enough to regard such solutions as purely technical, concentrating only on the software, which is a problem for if the problem concerns the relationship between software and business,...