Safety-critical systems, formal methods and standards

Standards concerned with the development of safety-critical systems, and the software in such systems in particular, abound today as the software crisis increasingly affects the world of embedded computer-based systems. The use of formal methods is often advocated as a way of increasing confidence in such systems. This paper examines the industrial use of these techniques, the recommendations concerning formal methods in a number of current and draft standards, and comments on the applicability and problems of using formal methods for the development of safety-critical systems on an industrial scale. Some possible future directions are suggested.