4.1.3 System Architectures and Evolvability: Definitions and Perspective

The term “System Architecture” has been widely used in the systems engineering community for at least three decades. Even today, however, the use of this term often elicits more confusion than understanding! In particular, “System Architecture” has been used to describe, at various times, both the evolutionary system framework (Rechtin 91) (Rechtin/Maier 97), and the specific physical design or component interrelationship (Hatley 88). Even when it is agreed that the “System Architecture” represents a framework in which detailed design is performed, it is not generally agreed what aspects of behavior and structure should be captured in such a framework, how it should be represented, and how it relates to the specifics of system design. This paper examines current definitions of “systems architecture”, and proposes a taxonomy of terms to distinguish “single use” from “enduring” applications of architecture. Particular attention is paid to enduring architectures and their relationship to systems engineering.