Tolerance to multiple transient faults for aperiodic tasks in hard real-time systems

Real-time systems are being increasingly used in several applications which are time-critical in nature. Fault tolerance is an essential requirement of such systems, due to the catastrophic consequences of not tolerating faults. In this paper, we study a scheme that guarantees the timely recovery from multiple faults within hard real-time constraints in uniprocessor systems. Assuming earliest-deadline-first scheduling (EDF) for aperiodic preemptive tasks, we develop a necessary and sufficient feasibility-check algorithm for fault-tolerant scheduling with complexity O(n²-κ), where n is the number of tasks to be scheduled and κ is the maximum number of faults to be tolerated