Compaq EK-SMCPO-UG. C01 manual Reconfiguring the Scsi Bus, Scsi Bus Length and External Cables

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

Table 3-2

SCSI Bus Length and External Cables

Bus

Rate

Bus Length

Longest COMPAQ Cable

Speed

MT/s

Mb/s

Meters

Feet

Number

Meters

Feet

Fast

20

40

25

82

BN21K-23

23

82

BN21L-23

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.

Table 3-3

Assigned Slot Device Addresses in the Pedestal

Slot #	0	1	2	3	4	5		6
Bus
			D0				D1
Device	8	9	10	11	8	9		10
Address

Reconfiguring the SCSI Bus

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.