Specifying embedded systems with statecharts and Z: an agenda for cyclic software components

The application of formal techniques can contribute much to the quality of software, which is of utmost importance for safety-critical embedded systems. These techniques, however, are not easy to apply. In particular, methodological guidance is often unsatisfactory. We address this problem by the concept of an agenda. An agenda is a list of activities to be performed for solving a task in software engineering. Agendas used to support the application of formal specification techniques provide detailed guidance for specifiers, templates of the used specification language that only need to be instantiated, and application independent validation criteria. We apply the agenda approach to a particular class of embedded safety-critical systems, the formal specification of which has been investigated in the case-studies of the German Espress project during the last two years.