IBM L5U, Информация по обслуживанию

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12-2
TS3400 Tape Library Maintenance Information
SCSI Sense Data Definition
The following is an example of a tape drive communication failure while attached to
an Open Systems host through a Fibre Channel link, using SCSI protocol. When the
host detected the failure, it built the following SCSI Sense Data record. An
explanation of the SCSI Sense Data breakout in this example follows.
Note: The bold area above represents the SCSI Sense Data presented by the host. The
regular font data (in this case many bytes of “zero”), designated by “ssss”
would normally contain device sense data, but with the kind of failure in this
example (COMMAND TIMEOUT), the host could not collect valid device
sense data, so zeros are the result and should be ignored. If the host had been
able to collect valid sense data from the drive, the first byte “ss” would be
“70”, “71”, “F0” or “F1”, and valid device sense data would be listed.
SCSI Sense Data Example 1 – Library Error
The following example of SCSI Sense Data was received from a RS/6000 Open
System host and shows a Tape Drive Failure and what the sense data would look like.
Unlike the previous situation with “SCSI Sense Data Definition”, this data contains
valid sense data as defined by the hex “70” in the first sense byte position. Therefore,
instead of all zeros as in the previous example, we have valid data to rely on. While
the data shows that this is a TAPE_ERR2, it could also be caused by a library failure.
The ASC/ASCQ points to a “Mechanical Positioning Error” while attempting a
“Move Medium” command (“A5”). For more information about Sense Data, refer to
the
IBM System Storage TS3400 Tape Library SCSI Reference .
SENSE DATA
aabb xxxx ccdd eeee eeee eeee eeee eeee ffgg hhxx ssss ssss ssss ssss ssss ....
0600 0000 1200 0000 0000 0000 0000 0000 0200 0300 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
Detail Data
aabb xxxx ccdd eeee eeee eeee eeee eeee ffgg hhxx ssss ssss ssss ssss ssss ....
Table 12-2. Sense data description
Hex Description
aa
bb
xx
cc
Length of the Command Descriptor Block (CDB) sent by the host. In this case, “06” bytes.
SCSI target address. In this example, SCSI address “00”.
Unused or reserved.
Start of CDB, cc is the operation code (byte 0). In this case, “12” which was an “Inquiry”.