The design of a fail-silent processing node for the predictable hard real-time system MARS

The MARS system has been developed at the Technical University of Vienna during the last decade with the goal of managing highly critical distributed control applications. It relies on a periodic, time triggered structure and the fail-silent behaviour of processing nodes. To validate the MARS concept we have developed hardware components and an operating system, both tailored to the specific needs of the system. This paper presents our approach towards achieving deterministic timing behaviour and the fail-silence propetty of processing nodes. The integral development of hardware and its associated operating system offered us the opportunity to implement specific features either in hardware or in software. This facilitated a very efficient design that has proved useful in practice for more than a year.