Safety and software intensive systems: Challenges old and new

There is an increased use of software in safety-critical systems; a trend that is likely to continue in the future. Although traditional system safety techniques are applicable to software intensive systems, there are new challenges emerging. In this report we will address four issues we believe will pose challenges in the future. First, the nature of safety is continuing to be widely misunderstood and known system safety techniques are not applied. Second, our ability to demonstrate (certify) that safety requirements have been met is inadequate. Third, modeling and automated tools, for example, code generation and automated testing, are introduced in a hope to increase productivity; this reliance on tools rather than people, however, introduces new and poorly understood problems. Finally, safety-critical systems are increasingly relying on data (configuration data or databases), incorrect data could have catastrophic and widespread consequences.