中文摘要：

针对分布式硬实时系统发生处理机故障后，当前周期内的任务实例和后续实例相对截止期限的不同紧迫程度，提出非紧迫周期内延迟策略——DNUP（delayinnon．urgentperiod）．该策略能够尽可能地推迟非紧迫实例的执行，使得低优先级实例有更多的机会完成其紧迫周期内的执行，从而实现处理器空闲（slack）资源的合理挪动．仿真实验结果表明，与其他几个著名的分布式容错调度算法相比，DNUP策略能够提高任务的可调度性，从而有效减少了所需处理机的数目．

英文摘要：

In distributed hard-real-time systems, when a hardware failure occurs, the task instance in current period is usually more urgent than the subsequent ones. According to this, a novel strategy of delay in non-urgent period （referred to as DNUp） is proposed. DNUP strategy can postpone the execution of non-urgent instance as late as possible and reserve the slack time for the instance with low priority. Thus it has a better chance to complete its execution in an urgent period. Extensive simulations reveal that DNUP can improve the schedulability of periodic tasks and achieve a remarkable saving on the number of processors required with respect to several well-known fault-tolerant scheduling algorithms.