IBM Power Series Handbook page 67

Location code topics
"Worldwide unique identifier" on page 57
Location code overview
Servers (system units and expansion units) use physical location codes to provide mapping of replaceable
units. Location codes are produced by the server's firmware, which positions them so that they can be
used to identify specific parts in a system. The location code format is the same for all servers.
If you are working with a specific location code, the feature immediately follows the first character
(U5886). Match the unit type and model to a link, as shown in the Unit type and locations table..
If the location code ends with -Txx-Lxx, the server's firmware could not identify the physical location.
When a physical location cannot be identified, a logical location code is provided. Where logical location
codes occur in enclosures, the locations topic for the enclosure has the known conversions listed. For
logical location codes with no conversion, contact your next level of support.
If the location code begins with UTMPx, the machine type, model, and serial number of the expansion
I/O unit have not been set yet, and this is a temporary unit identifier. To identify the unit, examine the
display panels on all of the expansion I/O units connected to the server until you find one with the same
characters in the first 5 digits of the top line in the unit's display. Record the unit's real machine type and
model from the unit label. Match the unit's machine type and model in the Unit type and locations table,
and follow the link to determine the service information.
Note: If locations for units are not in the preceding format, either they are not supported or there is a
problem in the firmware. Contact your next level of support.
Physical location codes
Physical location codes provide a mapping of logical functions and components (such as backplanes,
removable modules, connectors, ports, cables, and devices) to their specific locations within the physical
structure of the server.
Logical location codes
If the physical location cannot be mapped to a physical location code, the server's firmware generates a
logical location code. A logical location code is a sequence of location labels that identifies the path that
the system uses to communicate with a given resource.
Note: A resource has as many logical location codes as it has logical connections to the system. For
example, an external tape device connected to two I/O adapters will have two logical location codes.
An example of a logical location code is:
U7879.001.10ABCDE-P3-C31-T2-L23
The first part of the location code (through the T2 label) represents the physical location code for the
resource that communicates with the target resource. The remainder of the logical location code (L23)
represents which resource is indicated.
Description
Provides a definition for the worldwide unique identifier.
This group of digits follows the resource code labels and
always begins with the letter W.
Finding parts, locations, and addresses
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