Page 60 - UNI 101 Computer Science Handout.

Faculty of Nursing
Adult care Nursing Department

Figure 3 Multiple-Zone Disk Configuration.

Obviously, the largest number of sectors will be in the zone containing the outermost cylinders, Instead

of adjusting the motor speed, the disk controller buffers the data rate so that the data rate to the I/O

interface is constant, despite the variable data rate between the controller and the disk. Different
vendors call this technique multiple zone recording, zone bit recording (ZBR), or zone-CAV recording(Z-

CAV).

The platter on a hard disk drive is made of a rigid material and is precisely mounted. The heads on a

hard disk do not touch the surface; rather, they ride on a bed of air a few millionths of an inch above the
surface. The location of the heads radially is tightly controlled. This precision allows the disk to rotate at

high speed and also allows the designers to locate the tracks very close together. The result is a disk that

can store large amounts of data and that retrieves data quickly. A typical hard disk rotates at 5400

revolutions per minute (rpm), 7200rpm, or even 10,800rpm. A photograph of a hard disk assembly

60 Academic Year 2025/2026