Specifications

Chapter 9 SCSI Setup and Configurations 107
must be assigned to the SCSI interface and each SCSI device con-
nected to it, and the SCSI bus must be properly terminated.
9.3 SCSI IDs
Each device attached to the AIC-7892, as well as the AIC-7892 itself,
must be assigned a unique SCSI ID number from 0 to 15. 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 external SCSI devices, the SCSI ID usually is set with a switch
on the back of the device.
• SCSI ID numbers don’t have to be sequential, as long as the AIC-
7892 and each device has a different number.
• For example, 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.
• The on-board SCSI interface is preset to SCSI ID 7 and should not
be changed. This gives it the highest priority on the SCSI bus.
• Most internal SCSI hard disk drives come from the factory pre-set
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.
• If you are booting your computer from a SCSI hard disk drive
connected to the AIC-7892, the Boot SCSI ID setting in the