User`s guide

1-10 RAID Array 3000 Pedestal Storage Subsystem Hardware User’s Guide
Compaq Confidential – Need to Know Required
Writer: Bob Young Project: RAID Array 3000 Pedestal Storage Subsystem Hardware User’s Guide Comments:
Part Number: EK-SMCPO-UG. C01 File Name: b-ch1 Product Overview.doc Last Saved On: 12/4/00 1:51 PM
UltraSCSI Buses
The pedestal contains two, 16-bit, single-ended, wide UltraSCSI buses
(factory-configured as a split bus) that connects the controllers to the disk
drives.
The split-bus arrangement is divided into two-bus paths designated device port
0 and device port 1 as shown in Figure 1–6. Port 0 connects the controller to
the upper four devices in the pedestal (IDs 8 through 11) and port 1 connects
the controller to lower three devices (IDs 8 through 10). The device addresses
on the bus are set at the factory by an internal configuration switch
(Figure 1–7).
ID9
ID9
ID11
ID8
ID8
ID10
ID10
Top Controller
Device
Port 0
Device
Port 1
Bottom Controller (Optional)
ID=7
ID=6
ID=7
ID=6
3
0
0
0
-
5
1
Figure 1-6. UltraSCSI bus port and default SCSI ID assignments
When set to a specific position, the switch controls the addresses of each SBB
slot. Figure 1–8 identifies the pedestal slot locations and their corresponding
SCSI ID addresses for each device port.