IDE

This hard-drive interface has all of its controller electronics integrated into the drive itself. The IDE specification handles hard disks up to 504MB in size. Because of its simple instruction set and the short route between controller and drive, it's a quick and easy type of drive to use (unlike SCSI drives and the older Enhanced Small Device Interface (ESDI) drives from the late 1980s). But because it's a limited specification, IDE is gradually being superseded by an enhanced version, EIDE.