Principled Software Safety Assurance

This tutorial will be led by Dr Tim Kelly, a Senior Lecturer at the University of York. He will present the core principles that (should) shape the assurance activity for any safety-critical or safety-related software, and will explain how these principles relate to the objectives and requirements of a number of common software safety and assurance standards, including DO-178B/C, IEC61508 and CAP 670 SW01. Defence Standard 00-56 (a system safety standard) talks of presenting arguments and evidence that are commensurate with the level of risk. Examples will be given of how to use the notion of software criticality to moderate the nature and amount of evidence required for software. All of the above discussion will be set in the context of constructing and critically evaluating a software assurance case that can be used to support a system level safety case. The tutorial will explain how the development of a software assurance case can used to complement, rather than compete with, the requirements and guidance of software standards. Time will be reserved for discussion throughout. This tutorial should be of interest to anyone involved in the development, assurance, management or procurement of safety-critical or safety-related software systems.