Achieving Dependable Systems by Synergistic Development of Architectures and Assurance Cases

Assurance Based Development (ABD) is an approach to the construction of critical computing systems in which the system and an argument that it meets its assurance goals are developed simultaneously. ABD touches all aspects of the system lifecycle, but in this paper we focus on how the evolving assurance argument can guide architectural choices to increase system dependability. The goals with this approach to architectural choice are twofold. The first is to develop the architecture so that it provides the required evidence. The second is to refine the assurance case as architectural choices are made so that the evidence that will be provided supports the assurance claims. Combining development and assurance in this way facilitates detection—and thereby avoidance—of potential assurance difficulties as they arise, rather than after development is complete.