IBM H SERIES RS/6000 - Manual (Page 200)

from either direction, the broken loop does not prevent access to any data,
unless that data is on the failed disk drive module. If the loop is broken between
two disk drive modules, the ready lights on those modules flash to show that only
one SSA path is active. Also, the Link Verification service aid shows that only
one path is available to each disk drive module on the broken loop.
You can find the physical location of any disk drive module on the link by using
the identify function (see “The Identify Function” on page 7-31).
Notes:
a. In the lists of physical disk drives (pdisks) that are displayed by the service
aids, you might see:
????? Question marks show where an SSA loop is broken. No informa-
tion is available about any devices that are beyond this point.
***** Asterisks indicate an unconfigured device. That device might be:
Another SSA adapter that is in the same using system or in a
different using system.
An SSA device that is in the SSA network, but whose type is
not known. Such a condition can occur if, for example,
devices are added to the network, but the cfgmgr command
is not run to configure those devices into the using system.
For example:
┌──────────────────────────────────────────────────────────────────────────────────┐
│ LINK VERIFICATION
8 2386 │
│ │
│ SSA Link Verification for: │
│ ssa1 - 5 SSA ADAPTER │
│ │
│ To set or reset Identify, move cursor onto selection, then press Enter. │
│ │
│ Physical Serial# Adapter Port │
│ │
│ A1 A2 B1 B2 Status │
│ {TOP} │
│ pdisk 11111111 Good │
│ pdisk1 22222222 1 Good │
│ ????? │
│ pdisk3 44444444 4 Good │
│ pdisk4 55555555 3 Good │
│ pdisk5 66666666 2 Good │
│ pdisk6 77777777 1 Good │
│ pdisk7 88888888 Good │
│ pdisk8 99999999 3 Good │
│ pdisk9 1 1 2 Good │
│ {MORE} │
│ │
│ F3=Cancel F1 =Exit │
│ │
└──────────────────────────────────────────────────────────────────────────────────┘
Note that the missing disk drive module (pdisk2) is represented by a line of
question marks.
7-40 RS/6000 Enterprise Server Model H Series User's Guide