Praxis Critical Systems Ltd

Building a software system is a well-understood prob-lem with a wide range of solutions, each suitable for some classes of system but not for others. The commercial success of a software system, however, depends on its acceptance by the customer. Therefore, the developer must demonstrate that a system is fit for its purpose. A common view is that following a specified software or systems development pro-cess is adequate for this purpose. However, as software and safety standards move from a prescriptive to goal-oriented form, this demonstration of fitness will become better tai-lored to each system. In this paper we examine how existing processes and products can be used to build an evidence-based case for high-assurance system acceptance. We draw on our own experience of developing and delivering such systems, and make practical recommendations for improving acceptance rates. We show how existing technologies and tools can sup-port this process. 1