Scheduling Analysis under Fault Bursts

Real time systems must respect their temporal constraints both in nominal and degraded conditions. Environment disturbances cause faults which are revealed by errors during task execution. Therefore, schedulers must be fault tolerant to guarantee no missed deadline. Phenomena like electromagnetic fields disturb real-time systems on an extended period of time. It is difficult to forecast faults and their consequences to build efficient fault-tolerant systems. The classical fault models deal with pseudo-periodic faults. They are not made for phenomena extended in time. This paper intends to describe electromagnetic disturbances in a new fault model, named fault burst model. In accordance with the fault burst model, we provide error recovery strategies. We study the effects of the strategies on the schedulability analysis to guarantee fault tolerance when fault bursts occur. Finally we suggest a method to evaluate the fault resilience of a real-time system under our fault model.