HP Array Controller HSG V8.7 Software - Manual (Page 31)

Introducing the UltraSCSI RAID Enclosure
UltraSCSI RAID Enclosure 1–9
2 — Establishing SCSI bus device addresses 8, 9, 10, and 11
3 — Establishing SCSI bus device addresses 12, 13, 14, and 15
Note
Not all array controllers support an UltraSCSI RAID
subsystem with more than one enclosure. Refer to the array
controller documentation to ensure that the controller
supports expanded configurations.
Expansion EMU
An EMU installed in an expansion enclosure is an expansion EMU.
This EMU communicates with the master EMU over the EMU-EMU
communications bus. Upon loss of communications with the master
EMU, the expansion EMU assumes control of certain expansion
enclosure functions. In this state, the expansion EMU cannot
communicate with the UltraSCSI controller.
I/O Module
The I/O modules provide termination for the internal UltraSCSI buses
and are the connection points for the cables connecting the six buses
to the expansion enclosures.
SCSI Bus Controller
A hardware-software device that manages SCSI bus communications.
Controllers typically differ by the type of interface to the host and
provide functions beyond those the devices support. A host port
adapter connects the host to the controller. Other terms commonly
used for the SCSI bus controller include array controller, host
controller, or controller.