User`s guide

KZPBA–CA PCI-to-UltraSCSI Host Adapter
2–2 EK–KZPBA–UG. B01
SCSI ID Selection
The KZPBA–CA host adapter is assigned SCSI ID 7. For the SCSI devices
mounted in the storage shelf, the device address is determined by its physical
location in the storage shelf, with the slot number equating to the SCSI ID
number.
SCSI Bus Termination
For a single-ended bus connection, the single-ended bus is terminated at one end
by the KZPBA–CA adapter and at the other end by the StorageWork shelf
Personality Module
2.2 Configuration Topography
You can configure the host adapter to be in the middle or at the end of the SCSI
bus.
Configure the host adapter in the middle of the SCSI bus by using both internal
connectors, each connected to one or more internal SCSI devices.
When the host adapter is at one end of the bus, the bus is terminated at the host
adapter and at the last SCSI device. When the host adapter is in the middle of the
bus, the bus is terminated by the last SCSI device at each end of the bus.
2.2.1 SCSI Cable Selection
Always select high-quality SCSI cables to use in your system. Because single-
ended host adapters support UltraSCSI transfer rates, the use of high-quality
cabling is especially critical. Cables of a lesser quality can cause data corruption,
parity errors, and other problems.
Round external SCSI cables vary widely in quality and electrical characteristics.
Ascertain, from your cable supplier, that external cables meet SCSI-2 standards.
The following are some cable selection guidelines:
•
Use layered twisted pair cables with 25-wire pairs
•
Use cables that have a single-ended impedance range of 80-100ohms
•
Do not use cables shorter than 30 cm (11.8 inches) between any two SCSI
devices
2.2.2 SCSI Bus Lengths
The length of a SCSI bus segment is the cable distance between the two bus
terminators, with each terminator located at an end of the bus segment. The
length of the Single-ended SCSI bus should not exceed 1.5 meters when
operating in UltraSCSI mode, using internal connectors to internal devices. If
you are using an UltraSCSI DIGITAL StorageWorks enclosure, refer to the