On the Semantics of Architectural Decisions

Abstract

The architecture of a software system results from decisions made by the developers throughout the software life cycle. Any decision pertaining to software architecture is called an architectural decision. Architectural decision modelling captures the dependencies that exist between the decisions and serves as a foundation for knowledge management and reuse. Several models have been described in the literature, using natural language to explain the basic notions and class diagrams to show relations between them. However, a formal definition of an architectural decision is still missing. This paper analyzes existing architectural decision models and provides a formal background for the basic notions that all the models have consensus on. The major contribution of this paper is twofold: to propose a set-theoretic definition of the semantics of architectural decisions; and to show an explicit interpretation of basic relationships that exist in the architectural knowledge. The formalization can help in understanding the meaning of architectural decisions and the meaning of relations that exist between the decision elements. UML-based metamodel for architectural design decisions is also presented.