User`s guide

Chapter 3. Maintenance

EK–SMCPO–UG. A01 3–13

Table 3–2 SCSI Bus Length and External Cables

Bus Rate Bus Length Longest DIGITAL Cable

Speed MT/s MB/s Meters Feet Number Meters Feet

Fast 20 40 25 82 BN21K-23

BN21L-23

23 82

The SCSI bus in your pedestal is factory-configured as a split bus. One bus is

designated bus

and the other as bus

. 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

and 8 through 10 for bus

. Table 3–3 shows a listing of the de-

vice addresses for each bus and their corresponding pedestal slot location.

Table 3–3 Assigned Slot Device Addresses in the Pedestal

Slot #

0 12 3 456

Bus D0 D1

Device

Address

8 9 10 11 8 9 10

3.7.1 Reconfiguring the SCSI Bus

WARNING

Only qualified service personnel should reconfig-

ure 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 in-

volves 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 Chap-

ter 4 of this guide.