中文摘要：

提出一个基于抢占性实时周期任务的可靠性调度模型，该模型与现有可靠性模型相比充分考虑了单处理机故障容错情况下的系统可靠性，因而更加接近现实和精确．在此基础上，提出一个基于异构分布式系统的实时容错调度算法IRDFTAHS，IRDFTAHS算法以提高系统的可靠性为目标来进行任务的分配，从而在不增加硬件代价的前提条件下通过调度增加了系统的可靠性．该算法同时支持主动和被动两种方式的副版本，使得容错调度算法具有更大的灵活性．最后，通过仿真实验对IRDFTAHS和现有的调度算法在几个方面进行比较．实验结果表明，IRDFTAHS算法的综合性能优于现有算法．

英文摘要：

This paper proposes a novel reliability model based on preemptive periodic tasks. Compared with existing reliability models in literature, the proposed reliability model can be one- processor-failed fault-tolerant, which makes it more realistic and precise. Moreover, a real-time fault-tolerant scheduling algorithm based on heterogeneous distributed systems, namely IRDFTAHS, is presented. IRDFTAHS tries to assign tasks copies in a way to improve reliability of system. In addition, IRDFTAHS considers backup copy in both active and passive status, which makes the proposed algorithm more flexible than existing algorithms. Finally, simulation experiments are carried out to compare the algorithm with existing ones in several aspects. The experiments results show that the IRDFTAHS generally performs significantly better than existing algorithms.