Architectural concepts for embedded systems in safety-critical applications

The programmable electronic systems currently employed in safety-critical applications follow either a strictly periodical or a task-based operating policy. These policies are discussed with regard to safety aspects, and a novel real-time execution concept combining their advantages is introduced. Its main characteristics are quantisation of time into discrete execution intervals, and partitioning of tasks into execution blocks matching these intervals. This operating principle features task-based software execution without utilising interrupts, eases integration into a holistic safety concept, and complies particularly well with the safety standard IEC 61508.