Fault Tolerant Real Time Systems

Real time systems are systems in which there is a commitment for timely response by the computer to external stimuli. Real time applications have to function correctly even in presence of faults. Fault tolerance can be achieved by either hardware or software or time redundancy. Safety-critical applications have strict time and cost constraints, which means that not only faults have to be tolerated but also the constraints should be satisfied. Deadline scheduling means that the taskwith the earliest required response time is processed. The most common scheduling algorithms are :Rate Monotonic(RM) and Earliest deadline first(EDF).This paper deals with the interaction between the fault tolerant strategy and the EDF real time scheduling strategy.