Introduction SCSI Host Adapter Communication SCSI IDs Setting SCSI IDs SCSI Technology Terminators SCSI device drivers Narrow and Wide SCSI 1 2 and 3 SCSI Interfaces SCSI Installations
Technicians’ Site

Copyright © Anne Watson

Home. e-learning. Multiple Choice. Handouts and Links. Contact Anne. About this site.


SCSI (pronounced "scuzzy") stands for Small Computer System Interface and is standard for communication between a subsystem of peripheral devices and the system bus.

The SCSI bus is a system that can contain, and be used by, up to seven or fifteen, devices, depending on the SCSI standard.

If a motherboard does not have an embedded controller, the gateway from the SCSI bus to the system bus is the host adapter. This is a card inserted into an expansion slot on the motherboard.

The adapter card is responsible for managing all the devices on the SCSI bus. A host adapter can support both internal and external SCSI devices, using one connector on the card for a ribbon cable to connect to internal devices and an external port that supports external devices.

All the devices and the host adapter form a single daisy chain.

The example below has two internal devices and two external devices, with the SCSI host adapter in the middle of the chain.