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Identifying and Addressing SSA Devices
This section describes how SSA adapters and devices are known to the using system
programs.
Location Code Format
Location codes identify the locations of adapters and devices in the using system and
its attached subsystems and devices. These codes are displayed when the diagnostic
programs isolate a problem. For information about the location codes that are used by
the using system, see the Operator Guide for the using system.
A B
-
The location code shows only the position of the SSA adapter in the using system and
the type of device that is attached. The location of the device within the SSA loop must
be found by use of a service aid. The service aids use the IEEE-standard 16-digit
unique ID of the device.
Pdisks, Hdisks, and Disk Drive Identification
The physical disk drives (pdisks) in an SSA subsystem can be configured as logical
units (LUNs). A LUN is also known as an hdisk, and can consist of one or more
physical disk drives. An hdisk in an SSA subsystem might, therefore, consist of one
pdisk or several pdisks.
The configuration software allocates an identification (hdisk and pdisk number) to each
disk drive during the configuration of the SSA link. The disk drives do not have fixed
physical addresses.
The numeric identifiers of pdisks, hdisks, and the disk drive slots are not related to each
other. For example, pdisk1 is not necessarily in slot 1 of the physical unit in which it is
installed.
C D
-
E F
-
G H
Unused
Unused
Unused
P = Physical disk drive
L = Logical disk drive
Adapter position
(number of the slot, 1 through 8,
containing the SSA adapter)
System I/O bus identifier
Expansion adapter position
Expansion drawer
Chapter 2. Introducing SSA Loops
19
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