Analysis of Real-Time Systems Sensitivity to Transient Faults Using MicroC Kernel

Increasing complexity of safety-critical systems that support real-time multitasking applications requests the concurrency management offered by real-time operating systems (RTOS). Real-time systems can suffer severe consequences if the functional as well as the time specifications are not met. In addition, real-time systems are subject to transient errors originating from several sources, including the impact of high energy particles on sensitive areas of integrated circuits. Therefore, the evaluation of the sensitivity of RTOS to transient faults is a major issue. This paper explores sensitivity of RTOS kernels in safety-critical systems. We characterize and analyze the consequences of transient faults on key components of the kernel of MicroC, a popular RTOS. We specifically focus on its task scheduling and context switching modules. Classes of fault syndromes specific to safety-critical real-time systems are identified. Results reported in this paper demonstrate that 34% of faults that affect the scheduling and context switching functions led to scheduling dysfunctions. This represents an important fraction of faults that cannot be ignored during the design phase of safety-critical applications running under an RTOS