The cost of software development is among the major contributors to a new safety system. It is difficult to make people work faster but it is possible to make people work smarter. One way to achieve that is to introduce agile development methods. Agile methods are gaining more and more popularity, also in safety critical areas such as Railway, Automotive and Oil&Gas. Agile methods promise reduced costs and shorter time to market through incremental development, less production of unnecessary documents and more maintainable code.
In order to be able to use an agile approach without overloading the concept with large amounts of "nonagile" activities, we have split the software development from the rest of the IEC 61508 development process as shown in the diagram below. Only the software development itself is handled by the SafeScrum process - the rest is kept outside Scrum. Thus, the software developers develop software in SafeScrum while high level planning, systems design and decisions concerning safety – e.g. new safety requirements – are done outside the Safe Scrum process. Note that changes of high-level plans may be fed back from the RAMS validation to the Safe Scrum after each sprint.
Scrum's role in safety critical software development
The research on agile methods applied to development and certification of safety-critical software, and the development of SafeScrum is partially funded by the research council of Norway project # 228431 (SUSS agile development of safety-critical software)