Adaptive redundancy for fault-tolerant real-time systems

Reliability is an important aspect of real-time systems because the result of a real-time application may be valid only if the application functions correctly and its timing constraints are satisfied. There are two kinds of faults: hardware and software faults. In this paper, we consider hardware transient faults. Full replication or full hardware redundancy can achieve a high degree of reliability; however, it may waste resources. We propose a fault-tolerance approach, a hybrid method of rollback and replication, for the real-time systems which require both system reliability and the guarantee of meeting deadlines. We define that a task is fault-tolerant if it can be recovered from a transient error either by rollback or duplication. Our approach attempts to make as many tasks fault-tolerant as possible.