HP Surestore Disk Array 12h - And FC60 Service Manual page 26

BCCs
Two Backplane Controller Cards, BCCs, control the disks on one or two buses according to
the setting of the Full Bus switch. When the Full Bus switch is set to on, BCC A, in the top
slot, accesses the disks in all ten slots. When the Full Bus switch is off, BCC A accesses
disks in the even-numbered slots and BCC B accesses disks in the odd-numbered slots.
In full bus mode, all ten disks can be accessed through either BCC. However,
Note
internally each BCC still manages five disks. This means that if the BCC that is
not connected to the SCSI channel fails, access to its five disks will be lost.
Failure of the BCC that is connected to the SCSI channel will render all ten
disks inaccessible.
A alignment guides
B SCSI Ports
C LEDs
D rotary switch
Figure 5
BCC
Disk Enclosure Components
26
E DIP switches
F locking screw
G cam lever