C-SCAN Provides a more uniform wait time than SCaN.提供比扫描 算法更均衡的等待时间。 The head moves from one end of the disk to the other servicing requests as it goes. When it reaches the other end however, it immediately returns to the beginning of the disk, without servicing any requests on the return trip.磁头从磁盘 的一段向另一端移动,沿途响应请求。当它到了另一端,就立 即回到磁盘的开始处,在返回的途中不响应任何请求。 Treats the cylinders as a circular list that wraps around from the last cylinder to the first o e.把所有柱面看成一个循环的 序列,最后一个柱面接续第一个柱面。 Applied Operating System Concepts 13.10 Silberschatz, Galvin, and Gagne @199913.10 Silberschatz, Galvin, and Gagne ©1999 Applied Operating System Concepts C-SCAN • Provides a more uniform wait time than SCAN. 提供比扫描 算法更均衡的等待时间。 • The head moves from one end of the disk to the other. servicing requests as it goes. When it reaches the other end, however, it immediately returns to the beginning of the disk, without servicing any requests on the return trip. 磁头从磁盘 的一段向另一端移动，沿途响应请求。当它到了另一端，就立 即回到磁盘的开始处，在返回的途中不响应任何请求。 • Treats the cylinders as a circular list that wraps around from the last cylinder to the first one. 把所有柱面看成一个循环的 序列，最后一个柱面接续第一个柱面