A storage device that magnetically writes data to and reads data from rotating disks or platters. To be totally tweaky, “drive” refers to the mechanical mechanism, while “disk” refers to the storage media. “Hard disk drive” or “HDD” refers to the entire unit, comprising both the mechanical and the storage aspects.
Hard disk drives may be either internally mounted in a computer or connected externally via a variety of means, including eSATA, USB, FireWire, and SCSI.
See also “Hard Drive.”