Open System Services Management and Operations Guide (G06.25+, H06.03+)

Managing OSS Files
Open System Services Management and Operations Guide—527191-002
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Considerations
You cannot use pax on labeled tapes. If you need to backup OSS files to labeled tapes
or restore OSS files from labeled tapes, use Backup and Restore 2.0.
You are also restricted when using pax to single write operations on unlabeled tape.
You can use the pax -W norewind option only when you combine all write operations
into one subshell; see the NOTES section of the pax(1) reference page either online
or in the Open System Services Shell and Utilities Reference Manual, or see
Consolidate Changing OSS Files on page 6-15.
Guardian tape devices are controlled by the Guardian tape process executing in the
Guardian environment and do not behave in the same way as UNIX devices. The
interaction between the tape process and the tape device is transparent to the pax
user.
To set the block size to its maximum when using tape, specify the pax command
-b28k flag.
When the pax utility accesses a tape archive, the pax utility issues a mount request to
the Guardian tape process. If you use the -W wait flag and no tape is correctly
mounted on the specified drive, the following message appears on the originating
terminal:
Device not ready or tape is not mounted?
The pax utility does not proceed with reading or writing a tape until an unlabeled tape
has been correctly mounted on the specified tape drive.
If you do not use the -W wait flag and no tape is correctly mounted on the specified
drive, pax exits.
To check for outstanding requests for tape drive status, use the Guardian utility
MEDIACOM. Invoke this utility from a TACL prompt or from the OSS shell with the
gtacl command. For information about MEDIACOM, see the DSM/Tape Catalog
Operator Interface (MEDIACOM) Manual.
If there are errors related to the device or to the mounted tape during the tape-mount
process, one or more of the following messages are sent to the originating terminal:
Tape is unloaded -- media is write protected
Tape mount error (Guardian file system error: n)
Tape read failed with Guardian file system error: n
Tape write failed with Guardian file system error: n
where n is a Guardian file-system error number. You can use the Guardian ERROR
utility to find the meaning of the error number. Correct the error and remount the tape
or cancel the tape-mount request using the MEDIACOM utility.
If the request is canceled or the archive cannot be opened, the pax utility issues the
following message to the originating terminal:
filename cannot be opened, Guardian file system error: n
where n is a Guardian file-system error number.