A new scheduling algorithm called deferrable scheduling with time slice exchange (DS-EXC) was proposed to maintain the temporal validity of real-time data.In DS-EXC,the time slice exchange method was designed to further defer the release time of transaction instances derived by the deferrable scheduling algorithm (DS-FP).In this way,more CPU time would be left for lower priority transactions and other transactions.In order to minimize the scheduling overhead,an off-line scheme was designed.In particular,the schedule for a transaction set is generated off-line until a repeating pattern is found,and then the pattern is used to construct the schedule on-line.The performance of DS-EXC was evaluated by sets of experiments.The results show that DS-EXC outperforms DS-FP in terms of increasing schedulable ratio.It also provides better performance under mixed workloads.