Scheduling Analysis under Fault Bursts

International audience; 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 that no deadline will be missed. Phenomena like electromagnetic fields can disturb real-time systems on a extended period of time. During this period of time, it is difficult to forecast faults and their consequences to build efficient fault-tolerant systems. The classical fault models take into account the pseudo-periodic faults. A fault is described as a ponctual event which is separated from the next one by a minimum time interval. 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 adequation with the fault burst model, we provide error recovery strategies. These strategies are applied to a fixed-priority scheduler domain. Finally, we provide corresponding schedulability analysis to make the schedulers fault tolerant to fault bursts.