Configuring Your System
6-22 AlphaServer 1000 Rackmount Owner's Guide
External Configuration
When the SCSI bus is configured to permit a single external SCSI device (see Figure 6-8),
the bus is connected to the two 5¼-inch removable media devices and the fixed drives. A
cable connects the bus to an external bulkhead connector. At this point, you can terminate
the bus with an external SCSI terminator (12-41667-01), or you can attach an external
SCSI cable for connection to an external SCSI device. Note that the maximum length of
the external SCSI bus must be less than one meter to meet SCSI bus length restrictions.
If an additional SCSI controller option is plugged into the system, the integrated controller
can be connected to only the 5¼-inch removable media devices and then routed to an
external bulkhead connector (see Figures 6-9 and 6-10). The bus can be terminated at this
point using an external SCSI terminator (12-41667-01), or an external SCSI cable can be
attached to connect to external SCSI devices. To meet SCSI bus length restrictions, the
total external bus length must be less than 1.5 meters.
SCSI Controller Option Cards
All SCSI-2 devices are supported via EISA- or PCI-based SCSI controller cards. Use the
following rules to determine if a SCSI controller or SCSI device can be used on your
system.
•
The controller/device must be supported by the operating system. Consult the software
product description or hardware vendor.
•
No more than seven devices can be on any one SCSI-2 controller, and each must have
a unique SCSI ID.
•
The entire SCSI bus length, from terminator to terminator, must not exceed 3 meters
for single-ended SCSI-2.
