IBM totalstorage 326 User Reference page 175

executes diagShow every 4 seconds, continuously, until stopped by
pressing Enter. This may be used to isolate a bad GBIC. A port
with a changing LLI_errs value is prefixed by ** in the display.
portLoopbackTest
Verifies the intended functional operation of the hub by sending
frames from each port's transmitter back to the same port's receiver
through an internal hardware loopback. It tests the hub circuitry up
to the serial output of the ASIC.
portRegTest Checks each register and static memory located on the system
board. Registers are set under firmware control and are used to
control the hardware route selection and other internal hardware
functions.
The loopback point chosen by this command depends on what kind
of GBIC module is present. If a GBIC other than an optical SWL or
LWL GBIC is present, the test loops back only at the input (rather
than the output) of the serial link. Copper and unknown GBIC types
fall within this category. On the hub, ports 0 - 6 are all treated as if
a SWL GBIC is present.
If you do not include the nFrames parameter (specifying the
number of frames) when you issue the command, the loopback test
runs continuously until you press Enter again. If the test does not
find an error, there is no output. You can choose to continue the
test, view statistics, or view an error log.
ramTest Checks CPU RAM memory. This test validates proper memory
function.
setGbicMode Forces crossPortTest or spinSilk to limit its testing to only those
ports whose GBICs or imbedded optics are detected present.
Entering the command with the 1 parameter enables GBIC mode.
Entering the command with the 0 parameter disables GBIC mode.
spinSilk Verifies the intended functional operation of the hub by sending
frames from the transmitter of each port through the GBIC, the
imbedded optics and external cable, and back to another port's
receiver at the full hardware speed of 1 GB per second. It exercises
the entire path of the hub.
Because the CPU is not comparing data on each frame as with the
other two frame tests, the DIAG-DATA error is never reported during
spinSilk. However, the other error messages defined for
crossPortTest and their corresponding probable causes and actions
are applicable to spinSilk.
The operation of spinSilk is affected by the state of the GBIC mode.
The GBIC mode is activated by executing the following command
prior to executing the spinSilk command:
sw:admin> setGbicMode 1
When activated, only ports with a GBIC or embedded optics
present are included in the spinSilk list of ports to test. For
example, if GBIC mode is activated, ports 0 - 6, which have
imbedded optics, are always included in the testing. Port 7 is only
included if a GBIC is plugged into it.
Appendix E. Setup procedures and diagnostics for the Fibre Channel Hub
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