ASUS PCI-SIU2 User’s Manual
13
2. Getting Started
2
Host Adapter and the SCSI Bus
The PCI-SIU2 is a bus mastering host adapter which works with the host com-
puter to provide control for the SCSI bus. By daisy chaining peripheral de-
vices together, up to 15 SCSI devices can be connected to the PCI-SIU2. The
host adapter can be placed in any standard PCI slot on the bus.
SCSI Bus Preparation
Peripheral devices attached to the SCSI bus can either be an internal or exter-
nal device. Each peripheral has a specific device ID, commonly referred to as
a “SCSI ID.” The SCSI ID determines priority when two or more devices are
trying to use the SCSI bus at the same time. No two devices can have the same
ID; the device ID uniquely defines the device to the SCSI bus. The PCI-SIU2
is preset to SCSI ID 7 and should not be changed. This gives it the highest
priority on the SCSI bus. Please refer to your peripheral documentation to
determine switch or jumper settings for SCSI ID’s. Here are some general
guidelines for SCSI IDs:
•
SCSI ID numbers don’t have to be sequential, as long as the PCI-SIU2
and each peripheral has a different number. For example, you can
have an internal SCSI peripheral with ID 0, and an external SCSI
periphera1 with ID 6. Gaps in the sequence of numbers don’t matter.
•
For internal SCSI peripherals, the SCSI ID usually is set by configur-
ing a jumper on the peripheral.
•
For external SCSI peripherals, the SCSI ID usually is set with a switch
on the back of the peripheral.
•
SCSI ID 7 has the highest priority on the SCSI bus. The priority of the
remaining IDs, in descending order, is 6 to 0, 15 to 8.
•
Most internal SCSI hard disk drives come from the factory preset for
SCSI ID 0.
