a) Special type of disk drive designed for moving very large amounts of information as quickly as possible.

b) A very widely used high data rate general purpose parallel interface.

A maximum of eight devices can be connected to one bus, for example a controller, and up to seven disks or devices of different sorts - Winchester disks, optical disks, tape drives, etc., and may be shared between several computers. SCSI specifies a cabling standard (50-way), a protocol for sending and receiving commands and their format. It is intended as a device-independent interface so the host computer needs no details about the peripherals it controls. But with two versions (single-ended and balanced), two types of connectors and numerous variations in the level of implementation of the interface, SCSI devices cannot “plug & play” on a computer with which they have not been tested. Also, with total bus cabling for the popular single-ended configuration limited to 18 feet (6 meters), all devices must be close to each other.