The transient server approach to scheduling time-critical recovery operations

A scheduling approach is given for servicing the nondeterministic workload demands of time-critical recovery operations triggered by the detection of errors in periodic real-time workloads. This approach, referred to as the transient server, has been developed within the context of fixed-priority preemptive systems. For these systems, it is proved that deadline monotonic scheduling is optimal in maximizing the service opportunities for recovery requests. A scheduling-theoretic framework for integrating time-invariant deadline- and criticalness-based priorities is developed, motivated by the need to guarantee that the real-time workload experiences a graceful degradation during recovery