Ancient disk controllers

From: Eric Smith <eric_at_brouhaha.com>
Date: Mon Apr 19 00:58:38 1999

> SASI, incidentally was essentially a
> Single-Target-Single-Initiator SCSI so it wouldn't need a device ID switch.

SASI supported eight targets. Since there was only one initiator and no
disconnects, the initiator didn't need an ID. But the target devices still
needed IDs.

SCSI-1 added arbitration (for multiple initiators), disconnects (and
reselection), and the 10-byte commands (to support larger devices). I'm not
sure whether SASI supported the message phase; that may also be a SCSI-1
innovation.

Usually a SASI host can deal with SCSI disk drives. Sometimes a SCSI
host can deal with SASI targets, as long as it restricts itself to the
SASI commands.
Received on Mon Apr 19 1999 - 00:58:38 BST