Reconfiguring The Scsi Bus - Compaq StorageWorks TM RAID Array 3000 Pedestal Storage Subsystem Hardware User's Manual

3-14 RAID Array 3000 Pedestal Storage Subsystem Hardware User's Guide

Reconfiguring the SCSI Bus

SCSI Bus Length and External Cables
Bus Rate
Speed MT/s Mb/s
Fast 20
The SCSI bus in your pedestal is factory-configured as a split bus. One bus is
designated bus D0 and the other as bus D1. An internal eight-position step
switch in the cabinet controls the SCSI bus device address configuration of the
SBB slots in the pedestal. For the RAID Array 3000, the switch is preset at the
factory to configuration 6. This results in a device slot address assignment of 8
through 11 for bus D0 and 8 through 10 for bus D1. Table 3–3 lists the device
addresses for each bus and their corresponding pedestal slot location.
Assigned Slot Device Addresses in the Pedestal
Slot # 0
Bus
Device 8
Address
WARNING: Only qualified service personnel should reconfigure the SCSI bus.
Dangerous voltages are present within the subsystem. To prevent electrical
shock, always turn the subsystem off and disconnect the power cords before
removing the side panel.
If you want to reconfigure the SCSI bus (to add the Expansion Pedestal Option
to your subsystem installation for example), you must reconfigure the bus.
This involves powering down the subsystem installation, removing the left
side panel, and reconfiguring the bus by changing the setting of the
configuration switch. Adding the Expansion Pedestal Option to your
installation is described in Chapter 4.
Table 3-2
Bus Length
Meters Feet
40 25 82
Table 3-3
1 2 3
D0
9 10 11
Longest COMPAQ Cable
Number Meters
BN21K-23 23
BN21L-23
4 5 6
D1
8 9 10
Feet
82