User's Guide

1-5
Introduction
SCSI IDs
Each device attached to the Adaptec SCSI Card 39320D, as well as
the Adaptec SCSI Card 39320D itself, must be assigned a unique
SCSI ID number from 0 to 15 for each of the two SCSI buses. A SCSI
ID uniquely identifies each SCSI device on the SCSI bus and
determines priority when two or more devices are trying to use the
SCSI bus at the same time.
Refer to the device’s documentation to set the SCSI ID. Here are
some general guidelines for SCSI IDs:
■ For internal SCSI devices, the SCSI ID usually is set by
configuring a jumper on the device. For further information on
changing the SCSI ID, refer to the device manufacturer’s
documentation.
■ For external SCSI devices, the SCSI ID usually is set with a
switch on the back of the device. For further information on
changing the SCSI ID, refer to the device manufacturer’s
documentation.
■ SCSI ID numbers do not need to be sequential, as long as the
Adaptec SCSI Card 39320D and each device has a different
number. For example, on each of the two SCSI buses you can
have an internal SCSI device with ID 0, and an external SCSI
device with ID 6.
■ SCSI ID 7 has the highest priority on the SCSI bus. The priority
of the remaining IDs, in descending order, is 6 to 0, then 15 to 8.
■ On both SCSI buses (channels) the Adaptec SCSI Card 39320D
is preset to SCSI ID 7 and should not be changed. This gives the
card the highest priority on the SCSI bus.
■ Most internal SCSI hard disk drives come from the factory
preset to SCSI ID 0.
■ If you have 8-bit (or Narrow) SCSI devices, they must use SCSI
IDs 0, 1, 2, 3, 4, 5, or 6. SCSI ID 0 is recommended for the first
SCSI hard disk drive.
ASC-39320D UG.book Page 5 Monday, July 22, 2002 1:42 PM