IBM H Series Installation And Service Manual page 179

GH is used to identify a port, device, or FRU. For example:
For async devices GH defines the port on the fanout box. The values are 00 to
15.
For a diskette drive H defines which diskette drive 1 or 2. G is always 0.
For all other devices GH is equal to 00.
For integrated adapter, EF-GH is the same as the definition for a pluggable adapter.
For example, the location code for a diskette drive is 01-D1-00-00. A second
diskette drive is 01-D1-00-01.
For SCSI the location code is defined as:
AB-CD-EF-G,H
| | | | |
| | | | Logical Unit address of the SCSI Device
| | | Control Unit Address of the SCSI Device
| | Connector ID
| devfunc Number, Adapter Number or Physical Location
Bus Type or PCI Parent Bus
Where AB-CD-EF are the same as non-SCSI devices.
G defines the control unit address of the device. Values of 0 to 15 are valid.
H defines the logical unit address of the device. Values of 0 to 255 are valid.
There is also a bus location code that is generated as '00-XXXXXXXX' where
XXXXXXXX is equivalant to the node's unit address.
Examples of physical location codes displayed by AIX are:
Processor card in system board slot 1
P1-C1
Memory module in system board slot 2
P1-M2
Memory module 12 in card in system board slot 2
U1-P1-M2.12
Chapter 3. Error Code to FRU Index
3-71