Scheduling Analysis under Fault Bursts

Real time systems must respect their temporal con-straints both in nominal and degraded conditions. Envi-ronment disturbances cause faults which are revealed by errors during task execution. Therefore, schedulers must be fault tolerant to guarantee no missed deadline. Phe-nomena like electromagnetic fields disturb real-time sys-tems on a extended period of time. It is difficult to fore-cast 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 electro-magnetic disturbances in a new fault model, named fault burst model. In adequation with the fault burst model, we provide error recovery strategies. Finally, we study the effects of strategies on the schedulability analysis to guar-antee fault tolerance when fault bursts occur.