设计程序模拟先来先服务FCFS，最短寻道时间优先SSTF，SCAN和循环SCAN算法的工作过程。假设有n个磁道号所组成的磁道访问序列，给定开始磁道号m和磁头移动的方向（正向或者反向），分别利用不同的磁盘调度算法访问磁道序列，给出每一次访问的磁头移动距离，计算每种算法的平均寻道长度。-Design program to simulate the first come first served FCFS, shortest seek time first SSTF, the working process of SCAN and cyclic SCAN algorithm. Assuming a n track number composed of the access sequence, given start track number m and head movement direction (forward or backward), respectively, using the disk scheduling algorithms of different access track sequence, head movement distance are given every visit, calculating the average search length of each kind of algorithm.