A technique for detecting and diagnosing faults at the processor level in a multiprocessor system is described. A process is assigned whenever possible to two processors: the processor to which it would normally be assigned (primarily) and an additional processor that would otherwise be idle (secondary). Two strategies are described and analyzed: one that is preemptive and another that is nonpreemptive. It is shown that, for moderately loaded systems, a sufficient percentage of processes can be performed redundantly using the system's spare capacity to provide a basis for fault detection and diagnosis with virtually no degradation of response time. A multiprocessor that uses the approach for detecting faults at the processor loads is described.>

A technique is described for detecting and diagnosing faults at the processor level in a multiprocessor system. In this method, a process is assigned whenever possible to two processors: the processor that it would normally be assigned to (primary) and an additional processor which would otherwise be idle (secondary). Two strategies will be described and analyzed: one which is preemptive and another which is non-preemptive. It is shown that for moderately loaded systems, a sufficient percentage of processes can be performed redundantly using the system's spare capacity to provide a basis for fault detection and diagnosis with virtually no degradation of response time.