A
hard drive that is outside of the
computer case in its own enclosure. Most
support the
IDE interface and are
slightly bigger than a hard drive itself. When purchasing an external hard
drive you can buy a full external hard drive system that consists of both the
hard drive and the enclosure, or you can purchase just the enclosure to hold
your own hard drive. External hard drives may contain a fan for cooling and are popular because they are portable devices and can be
stored securely under lock and key since they are not inside the computer case.
An external hard drive is connected to the computer system with a single
high-speed interface cable, usually with
plug-and-play interfaces such as
USB or
FireWire.
Hard drive enclosures, also called
hard drive cages are made to support up to a
certain physical size of hard disk, so you need to check the
manufacturer's specification when buying just the enclosure.
See hard disk drive.
Also see
What's Inside a Hard Drive? in the Did You Know . . . ?
section of Webopedia.
