Developing a high-quality software tool for fault tree analysis

Sophisticated dependability analysis techniques are being developed in academia and research labs, but few have gained wide acceptance in industry. To be valuable, such techniques must be supported by usable, dependable software tools. We present our approach to addressing these issues in developing a dynamic fault tree analysis tool called Galileo. Galileo is designed to support efficient system-level analysis by automatically decomposing fault trees into modules that are solved separately using appropriate techniques. Usability is addressed by a software architecture based on a component-based design technique that we call package-oriented programming. We integrate multiple, volume-priced mass-market software packages to provide the bulk of the tool superstructure. To address tool dependability, we are developing natural language and partial formal specifications of fault tree elements, and we exploit the inherent redundancy associated with multiple analysis techniques as an aid in testing