See also: Hardware
Acronym: Hard Disk Drive (also HD: Hard Drive or Hard Disk)
Magnetic computer components that store information. Taken in contrast to the original storage medium: "floppy" disks, hard disks are unmoving small boxes instead of thick card-like plates which are inserted into a separate drive. At the core, they consist of a spinning magnetic disk and a "head" that can read data from and write data to the disk. Internal hard disks are usually connected to the computer's motherboard using an IDE or SCSI interface. External hard disks can be connected using USB, Firewire or RS232 serial ports.
Hard drives can be as small as a quarter or as large as 5x7 inch, although most modern drives are about 3x5 inch.
Caution: When handling a hard disk drive or an old floppy, avoid proximity to magnets, which can erase information.