Problems encountered during an upgrade of a large-scale information system at a major educational institution form the basis of the study described in this paper. The paper describes the influences that preexisting systems have on such an upgrade.

The authors discuss the implications of agencies, institutions, and large-scale systems. They define three types of agency constructs: material agencies that act through natural laws and establish constraints; human agencies that act to establish courses of action to achieve desired ends; and discipline agencies that involve concepts, practices, and values. The authors introduce the “surface of emergence,” a concept affected by various structuring processes, extending through time and space.

The case study describes how prior systems, their adherents, and rules of engagement (budgets, timing, and regulations) all impact and affect system engineering upgrade processes. Begun in 1989, the upgrade, originally scheduled for a two-year implementation, followed by a three-year deployment, was sublimely influenced and delayed. The authors conclude by observing “a strong tendency in the systems development literature to focus primarily on the system under development and to under-emphasize the role of pre-existing information systems.” They conclude that the literature treats preexisting information systems as black boxes, serving as resources or constraints on development. The authors observe that preexisting systems and their constituency are active forces in systems upgrades, and influence the upgrade in unexpected ways.

Many of the interactions described could apply to any large computing system. The US Department of Defense is designing a 21st century telecommunications upgrade to modernize communications within the department. This paper and its analysis could well apply to that effort.