Chapter 6 SCSI Module FRUs 6-15
6.6.1 External Terminators for Special Dual-Bus JBOD
Maintenance
If you have JBOD I/O modules, part number 370-5396-02/50 or higher, use this
information.
Note – This new I/O module supports both single-initiator and multi-initiator dual-
bus configurations. The older I/O module supports only single-initiator dual-bus
configurations.
If you have earlier I/O modules and do not have JBOD I/O modules, part number
370-5396-02/50 or higher, see “Older JBOD Dual-Bus Configurations” on page 6-16.
To preserve all original SCSI IDs and correct termination on a dual-bus JBOD in a
cluster environment, insert an external terminator in all cases where a SCSI port
becomes empty that was not empty in the original configuration. This maintains the
SCSI drive IDs for the active host connections. For an example of two removed
cables and two inserted terminators, see
FIGURE 6-3.
In a dual-bus configuration, the SCSI IDs change according to the termination on the
SCSI ports. If your original configuration has both SCSI ports connected on a bus
connected to host(s), the SCSI IDs are 0 to 5. If only the bottom port is connected to
a host, the SCSI drive IDs are 8 to 13.
FIGURE 6-3 Two Terminators for Two Cables That Have Been Removed in a Dual-Bus
Configuration