A Modular Safety Case for an IEC 61508 Compliant Generic COTS Processor

Abstract

The transition from conventional federated architectures to integrated architectures enables integration of functionalities with different criticality levels (e.g., SIL1-4 according to IEC-61508) on the same computing embedded platform. These systems, also called mixed-criticality systems, provide benefits in terms of cost, size, weight, reliability and scalability. However, mixed-criticality systems are subject to rigorous certification processes, which can lead to prohibitive cost. This paper contributes with a generic modular safety concept of an IEC-61508 compliant generic multicore COTS device where the minimum reasonable safety arguments and evidences are defined. Furthermore, the use of the modularity approach limits the impact of changes to a reduced area of the safety case, thus allowing the reusability of its parts. Additionally, this approach enables decoupling the safety arguments of subsystems with different criticality levels (e.g., SIL1-4 according to IEC-61508). The work described in this paper has been reviewed and approved by a certification body, within the context of an European research project.