University of Technology, Sydney.

Abstract

Designated Contact: David Rowe Defining systems architecture evolvability- a taxonomy of change Evolvability is part of the alchemy of systems engineering. Designing a system that is evolvable is considered best practice in many industry domains. However, what does ‘evolvable ’ mean? And in what context does a system evolve? Reviewing the many factors of system change and their associated definitions, we conclude that a single definition for ‘evolvability ’ is not adequate. We assert that evolvability is a composite quality which allows a system’s architecture to accommodate change in a cost effective manner while maintaining the integrity of the architecture. In order to define evolvability as a composite, we propose a taxonomy which classifies the different aspects of evolvability. Using this taxonomy to select relevant systems architecting and design approaches, a systems architect can be confident in including those aspects of evolution most suitable to a particular application. The concepts introduced in this paper are applied to the Ericsson AXE telecommunications switching system for illustration and justification. 1