System Administration Guide: Devices and File Systems

Disk Terminology

Before you can effectively use the information in this section, you should be familiar with basic disk architecture. In particular, you should be familiar with the following terms:

Disk Term 



A concentric ring on a disk that passes under a single stationary disk head as the disk rotates. 


The set of tracks with the same nominal distance from the axis about which the disk rotates. 


Section of each disk platter. A sector holds 512 bytes.  


A data storage area on a disk. A disk block is 512 bytes. 

Disk controller 

A chip and its associated circuitry that controls the disk drive. 

Disk label 

The first sector of a disk that contains disk geometry and partition information. 

Device driver 

A kernel module that controls a hardware or virtual device. 

For additional information, see the product information from your disk's manufacturer.