A hard drive is a device that uses a ferromagnetic material to store data as part of a computer system. A hard drive may also be referred to as a hard disk drive or simply a hard disk. Hard drives consist of a completely sealed case that houses the following major components: (1) rigid disks, or platters, that are coated with tiny particles that can be magnetized to represent and store data. The disks are designed to be permanently enclosed within the drive, which is why hard drives are sometimes called fixed disk drives; (2) an electric motor and a spindle (i.e., an axle) that are used to rotate the disks; and (3) a mechanism called a read-write head that retrieves data from, and stores data to, the disks. There are two heads per disk (one for each side of the disk). The read-write heads can move from...