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本文建立了双头镜像磁盘系统的模型，提出双头镜像磁盘系统中并发定位操作的思想，然后给出并发定位磁盘调度算法．在阐述了模拟模型后，对并发定位调度算法及串行定位调度算法进行了性能模拟．从模拟结果中定量分析出并发定位调度的性能优于串行定位调度，并发定位调度算法使系统性能有很大的提高．文献[5]认为系统的寻道时间不受I／O请求到达率λ的影响，但本文的实验表明，采用了并发调度算法，I／O请求到达率λ与系统寻道时间之间将有一定的关系．本文最后阐明磁盘个数k是如何影响双头镜像磁盘系统性能的．
In this paper, the model of double-headed mirror disk system is established, and the conception of concurrent positioning operation in double-headed mirror disk system is proposed. Then the concurrent disk scheduling algorithm is given. After elaborating the simulation model, the performance of concurrent positioning and scheduling algorithm and serial positioning and scheduling algorithm are simulated. The performance of concurrent positioning and scheduling is quantitatively analyzed from the simulation results. The performance of the system is better than that of serial positioning and scheduling. The reference [5] considers that the seek time of the system is not affected by the arrival rate λ of the I / O request, but the experiments in this paper show that using the concurrent scheduling algorithm, the arrival rate λ of the I / O request and the system seek time will have A certain relationship. This article concludes with clarifying how the number of disks, k, affects the performance of a two-headed mirror disk system.