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Prof. John McDermid, Dr Rob Weaver, University of York
Friday June 24th, full day
Current best practice in the development of safety critical software requires the construction of a software safety case to demonstrate the acceptability of software in its system context. This is a process that should go hand in hand with software development to ensure that appropriate software safety evidence is obtained. This tutorial explains the role safety cases play in the development and certification of safety critical software. Specifically, the tutorial will consider the construction and presentation of software safety cases.
The tutorial will start with the basics of safety cases and how they can be used to show that safety requirements are satisfied by a set of safety evidence. The role of the safety argument within the safety case will be explained, including how its development can be used to identify suitable items of safety evidence to support the safety case. Building upon this we will examine software safety cases, in particular the principles and standards that affect their development. We shall consider construction and presentation of software safety cases from the perspective of the principles of software safety and the requirements laid down in standards such as Issue 3 of DS 00-56, MoD's main safety standard. The role of a software safety case in the software development lifecycles will be discussed.
The tutorial will combine presentations with exercises to familiarise the attendees with the concepts introduced. Examples will be used throughout to demonstrate how software safety cases can be practically developed. The exercises will give an opportunity for hands on experience of constructing software safety arguments. This will help expand attendee's skills at identifying types of software safety evidence and their understanding of how evidence is combined to show the acceptability of software with respect to safety.
This tutorial will give you an opportunity to learn about current best practice in software safety case development. The tutorial will explain how, as part of this process, software safety evidence is first identified and then combined to show safety. This process goes hand in hand with software design and implementation, and thus forms an integral part of the safety critical software development lifecycle.
The tutorial will give you a view of the changing emphasis in system safety cases. Previous practice relied on a process-based approach to development of safety critical software, but such standards inevitably lag technology, and can be seen as restrictive. Emerging best practice uses an evidence-based approach to demonstrating software safety as part of a system safety case.
John McDermid has been Professor of Software Engineering at the University of York since 1987. He runs the High Integrity Systems Engineering research group which is probably the world's largest academic group focusing on systems and software safety. He has taught system and software safety for over ten years, and has presented tutorials at conferences in Europe, the USA and Australia. He was instrumental in developing the goal structured notation now widely used for presenting safety cases, and has advised on the production of several system and software safety standards, including the CAA's SW01 and the MoD's DS 00-56 Issue 3.
Dr Rob Weaver is a Teaching Fellow in the Department of Computer Science and the University of York. Rob has been a full-time academic since 1999, the focus of his research being Safety. In particular Rob's research concerns the effect of software on system safety and the construction and presentation of safety cases. He lectures on the advanced MSc in safety critical systems engineering as well as presenting on industrial courses in System Safety Engineering and Management.
