User`s guide

KZPBA–CA PCI-to-UltraSCSI Host Adaptaer

3–14 EK–KZPBA–UG. B01

Figure 3–11 External SCSI Bus

HR-1

Term in atio n

Enabled

Personalit

Module

Host Adapter

Ternmination Enabled

KZPBA-13

3.5 SCSI Device Identification (SCSI ID) and Arbitration

Every device on a SCSI bus, including the Host Adapter, must be uniquely

identified with a SCSI ID. The SCSI ID serves two purposes:

•

It provides a unique identification to each device on the SCSI bus

•

It establishes the device’s priority on the bus during the arbitration phase

Setting the SCSI ID is a two-step process:

1. Determine the SCSI ID number that is to be assigned to each drive on the

SCSI bus. To set the ID for the various devices that are going to be on the

bus, read the manufacturer’s documentation for each device to determine the

appropriate switch or jumper settings.

2. Change SCSI IDs as necessary so that priority arbitration is as desired and

that no two devices have the same ID. The host adapter should be assigned

ID 7.

If more than one host adapter is installed, each host adapter has a separate SCSI

bus associated with it. The second SCSI bus can use the same ID numbers as

assigned to the first bus even though different devices are used.