What is a hard disk drive?
Computer applications and data are magnetically stored on a hard disk drive so they can be accessed at any time. When a computer is properly shut down, this information is saved on the disk drive, and is available again when the computer is restarted.
Physically, a hard disk drive consists of one or more disk platters. These disk platters are divided into cylinders, tracks, and sectors.
|Platters||Usually an aluminum-coated disk with an “oxide” or “thin film” media where the data is actually stored.|
|Tracks||Concentric rings on each platter where the data is stored magnetically.|
|Read/Write Heads||Usually one read/write head per platter surface, i.e., one head on the top of each platter, and one head on the bottom of each platter. All of the heads of a hard disk drive usually move in unison.|
|Sectors||Each track is broken down into smaller units named sectors. Each sector contains 512 bytes of data. On a hard drive you’ll usually see a number that defines the number of sectors per track – 32, 64, etc.|
|Spindle||The cylindrical object (or drum) that goes through the middle of each platter. The platters spin around the spindle similar to the way that an automobile tire spins on an axle.|
|Cylinders||The set of all tracks (on all platters) that are the same distance from the spindle.|
File System Structure: