IBM B50 manual Scsi devices/drives, Location code for Scsi devices and drives is defined as

For async devices, GH defines the port on the fanout box. The values are 00 to 15.

For a diskette drive, H identifies either 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.

SCSI devices/drives

The location code for SCSI devices and drives 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.

A bus location code is also generated as 00-XXXXXXXX, where XXXXXXXX is equivalent to the node's unit address.

Chapter 4. Location Codes 4-5