Product data

SCSI Bus Configurations and Addresses
The SCSI bus bridge card assigns the disk drive modules to a SCSI bus as determined
by the setting of the SCSI Bus Split switch that is on the switch card assembly. Three
SCSI bus modes are available:
v Single bus, one SCSI attachment (for example, a SCSI adapter in the using system):
SCSI address 7 is assigned to the SCSI attachment. The 2104 can have 14 disk
drive modules (SCSI addresses 0 through 6, and 8 through 14).
v Single bus, two SCSI attachments: SCSI addresses 5 is assigned to one SCSI
attachment; SCSI address 6 is assigned to the other. SCSI address 7 is reserved.
The 2104 can have 12 disk drive modules (SCSI addresses 0 through 4, and 8
through 14). The slots whose SCSI addresses are 5 and 6 must contain dummy disk
drive modules.
v Dual bus, two SCSI attachments: Each SCSI attachment has SCSI addresses 7.
Each SCSI bus can have seven disk drive modules (SCSI addresses 0 through 6,
and 8 through 14).
When single bus mode and two SCSI attachments are configured, SCSI addresses 5
and 6 are used by a SCSI attachment. Always install dummy disk drive modules into
the slots that have SCSI addresses 5 and 6 (see “SCSI Addresses” on page 25).
Terminator Terminator
Backplane
Terminator
Host bus adapter (HBA)
ID:7
Terminators
14 disk drive modules
Repeater
SCSI bus
bridge card
Enclosure
service
processor
Repeater
SCSI
interface
card
0123456 891011121314
Figure 13. Single Bus, One SCSI Attachment, 14 Disk Drive Modules
26 2104 Service Guide