Harmonizing the development, maintenance and enhancement of application systems

Abstract

Renovation is the computer‐aided rejuvenation of existing application systems according to sound engineering principles. It differs from traditional maintenance in that it bridges the gap between ageing and contemporary systems by making both amenable to engineering. For systems that were not engineered originally or that have deteriorated over time, it makes maintenance and enhancement far more tractable. Information systems engineering is conducted in four ways, three of which renovate existing systems so that the fourth can be conducted with less regard for system age or original technology: re‐engineering—transformation of bad code into good code, and bad data into good data, reverse‐engineering—derivation of specifications from good code and data, transverse‐engineering—transformation of derived specs into designed specs, forward‐engineering—creation of working systems from designed specs. The renovation approach to information systems evolution preserves much of the sizeable investment that organizations have in their systems while removing constraints imposed by old technologies. Development, maintenance and enhancement then proceed in harmony because systems are compatible and their definitions are flexible. Renovation should be considered during the formation of information systems architectures and project plans.