摘要： 将分布式系统的任务分配算法与处理器局部调度算法相结合，提出一种主动备份的、基于EDF 的分布式系统实时容错调度算法，其特点是主/副版本执行时间可以重叠。给出了该调度算法的任务集可调度的充分条件、任务集可调度所需最小处理器个数的计算方法。模拟结果比较了主动备份容错调度算法与被动备份容错调度算法，结果表明主动备份算法效率更优。

关键词: 分布式系统；主动备份；容错调度；主版本/副版本；EDF 算法

Abstract: The paper presents an initiative-backup fault-tolerant real-time scheduling algorithm for distributed systems. In the scheduling, processor’s local scheduling algorithm is EDF and the fault-tolerance’s technique is primary/backup copies. The execution time of the primary/backup copies may be overlapped. The schedulability of task set is analyzed and the method of calculating the minimal number of processor is given. The simulation compares the initiative-backup algorithm with the passive-backup algorithm, the result shows that the initiative-backup algorithm is more effective than the passive-backup algorithm

Key words: Distributed system; Initiative-backup; Fault-tolerant scheduling; Primary/backup copies; EDF algorithm