User`s guide

Chapter 2. Configuration Guidelines
EK–KZPBA–UG. B01 2–3
UltraSCSI Configuration Guidelines for cable lengths. For Fast-10 SCSI
configurations with BA356 StorageWorks enclosures, the maximum cable length
is 2.0 meters.
2.3 SCSI Bus Termination
The integrity of the data written to or read from a SCSI device can be seriously
compromised due to signal reflections caused by an unbalanced SCSI bus. An
unbalanced bus is the result of an improperly terminated or unterminated bus.
Therefore, failure to terminate the bus properly can result in a system crash or
even worse, data corruption.
A balanced bus is achieved by properly installing bus terminators on the SCSI
bus in relation to the host adapter and the SCSI devices. SCSI bus termination
on the KZPBA–CA Host Adapter ultra wide single-ended board is established
using one of the utility programs included in the host adapter kit.
Proper bus termination involves supplying termination power onto the SCSI bus
and the strategic placement of terminators on the bus. The KZPBA–CA PCI-to-
UltraSCSI Host Adapter provides active termination power and is generally the
only source of termination power required on the bus. However, Digital
Equipment Corporation recommends that all devices on the SCSI bus supply
termination power to ensure that there is a sufficient level of power along the
entire bus. SCSI devices are protected by a diode or similar semiconductor to
prevent back flow of the termination power when more than one device supplies
this power.
2.4 FAST-10 SCSI Configuration Example
Figure 2–1 shows a configuration topography that you can use for the
KZPBA–CA connected to a Fast-10 DS–BA356–XX StorageWorks shelf.