Installation guide

SCSI Cabling
3-14 DAC960PG Installation Guide
SCSI Cabling
Three things must be kept in mind while cabling the controller to the drives:
• SCSI Bus Termination
• System Performance
• SCSI Cable Length.
Every SCSI channel needs to be properly terminated with an appropriate
SCSI terminator, as previously mentioned. In general, no drives should be
terminated, and all drives must be shunted to supply TERMPWR on the
SCSI bus.
☛
Note
When connecting a Narrow SCSI (8-bit) cable to any
DAC960PG channel, the controller must be at one
end of the bus and
Termination Enabled
must be set
for that channel.
To get the best performance from the controller, the SCSI drives should be
equally distributed across the SCSI channels, and the controller’s data
transfer rate should be set to the optimum rate for the drives being used.
☛
Note
The SCSI transfer rate can be individually selected for
each of the three channels on the DAC960PG. For
more information, refer to the
DACCF Utilities
Installation Guide and User Manual
.
Figure 3-6 shows disk drives connected to two channels and grouped across
channels. The drive not included in a group can be a standby drive available
to either group. The tape drive is connected to a separate channel from the
disk drives.
Figure 3-6. Drive Grouping Example