The Research Of The Real-time Fault-tolerance Algorithm

Due to the development of real-time systems,more and more safety-critical applications are becoming to use real-time system as the kernel of the control system, and real-time system becomes an effective factor to determine the dependability of the safety-critical application.The dependable techniques of hardware of real-time have become mature enough,which make the software of real-time systems become the bottleneck of system dependability.As a very important technique for system reliability,software fault tolerance has become a very hot topic.So,the research and design of simple and practical scheduling is one of the most important topics of fault-tolerant real-time system.First,this paper introduces the architecture of the real-time system.Second,the classical real-time scheduling algorithms and real-time fault-tolerant scheduling algorithms are presented.On the basis of analyzing the main obstacle of real-time fault-tolerance,this paper focuses the view to the research of the fault-tolerant real-time scheduling.The main work includes:(1) Integrate real-time system supporting tasks with multilevel criticality into fault-tolerant real-time scheduling,and present two new fault-tolerant real-time scheduling algorithms named real-time fault-tolerant scheduling algorithm supporting tasks with multilevel criticality(RT-FT-SCA) and RT-FT-SCA-2 algorithm based on different system requirement.(2) Another algorithm is presented named real-time fault-tolerant scheduling algorithm supporting check-pointing and tasks with multilevel criticality (RT-FT-S2CA).The object of those algorithms is to improve the resource utilization in the absence of faults and to assure the fault-tolerant ability.(3) A real-time system scheduling simulator which is named RT-Simulator is designed and implemented.In RT-Simulator,not only classical algorithms such as RM,FT-RM,EDF and FT-EDF etc.,but also RT-FT-SCA,RT-FT-SCA-2 and RT-FT-S2CA are implemented.At last,the fault-tolerance scheduling algorithms are tested.The results show that RT-FT-SCA,RT-FT-SCA-2 and RT-FT-S2CA algorithms improve the utilization and tasks' throughput and keep their fault-tolerant abilities.