实时容错调度策略研究

华中科技大学硕士学位论文AbstractWith the real-time system extensively applied in various fields,real-time fault toleranttechnique has been deeply studied.Task's execution failure may result in disastrousconsequence.That proposes high demands for real-time and reliability for the real-timesystem.Real-time fault tolerant technique is a solution that put forward for the real-time faults.The main way is redundancy of the system resource.The study for hardware redundancytechnology is already very mature.This paper makes some preliminary discussion mainlydirected the software redundancy technology for real-time system.There are two software redundancy strategies:N versions software redundancystrategy and recovery block strategy.Mainly studies in recovery block softwareredundancy strategy.Adopted the primary/alternate versions task redundancy strategy,studies the real-time fault tolerance scheduling algorithm of the two versions in singleprocessor environment.Real-time fault tolerant scheduling algorithms improve on the real-time schedulingalgorithms.That improvements are mainly based on the RM algorithm and EDF algorithm.BCE algorithm improves on the RM algorithm.EBPA algorithm proposes the definition offault tolerant deadline,improves on the EDF algorithm.After defined fault tolerant laxity time and actual available time,a new fault tolerantalgorithm.FT-LLF algorithm,which is based on the two definitions and LLF algorithm,isaccording to the improvement of BCE algorithm on RM algorithm.FT-LLF algorithmeliminates the primary version task abortion rate and decreases the waste on CPU.Keywords:Fault Tolerant Laxity,Triggering time,Actual Available time,FT-LLFAlgorithm