The Development of a Commercial "Shrink-Wrapped Application" to Safety Integrity Level 2: The DUST-EXPERTTM Story

We report on some of the development issues of a commercial "shrink-wrapped application" -- DUST-EXPERT™ -- that is of particular interest to the safety and software engineering community. Amongst other things, the following are reported on and discussed: the use of formal methods; advisory systems as safety related systems; safety integrity levels and the general construction of DUST-EXPERT's safety case; statistical testing checked by an "oracle" derived from the formal specification; and our achieved productivity and error density.