Modification of Safety Critical Systems: An Assessment of three Approaches

摘要

This paper sums up the experience at SINTEF Telecom and Informatics on analysis of a safety critical systems for traffic control. After a short description of the system under consideration, the paper naturally falls into two parts. The first one is a description of two modifications, how they were implemented and how they were analysed for safety. The second one contains a discussion of the three methods used - FTA, FMECA and Code analysis. We here concentrate on how these methods differ in focus, the knowledge and information needed, and the types of problems they can handle.