z/VM: CP Commands and Utilities Reference - z/VM - IBM

SPXTAPE LOAD
files that loaded correctly before the system failure are skipped. However, even
with NODUP specified, you may still receive duplicate files if you are loading
the same file concurrently from more than one tape.
Keep in mind when using the NODUP operand that as the number of files in
the queue where the files are being loaded increases, the amount of
processing required to load the files from the tape increases dramatically. Each
file to be loaded is compared to every file in the queue. For example, if the
queue contains 1000 files and 1000 files are to be loaded, the result is over
one million comparisons.
The consequence of loading duplicate files is more serious for system data
files than for standard spool files. If the NODUP operand is not used when
loading system data files (or all files) from a tape for which no dump log is
available, you should check to make sure that duplicate files were not loaded.
If this happens, check the files to determine which should be kept and purge
the unnecessary files.
5. A logical SPXTAPE LOAD command, which may be a single command or a
sequence of appended commands, loads one tape file. A tape file (which ends
with one or more tape marks) contains one or more files dumped by one
logical SPXTAPE DUMP command. If multiple tape files exist on the tape
(written by multiple logical SPXTAPE DUMP commands), you must enter
separate SPXTAPE LOAD commands to load each tape file.
6. Do not load the same tape more than once during processing of the same
SPXTAPE command. Unpredictable results may occur, such as incomplete
files, duplicate files, or loss of spool DASD space. However, there may be
times when you need to reload the same volume. For example, if you
encounter an I/O error while reading a tape, you might want to retry the
operation. See 1500.
7. A file being loaded retains the same characteristics as the original file but is
assigned a new spool ID in the spooling system. The new spool ID is obtained
from the pool of IDs available to the recipient of the file.
8. If the file owner’s user ID does not exist on the system to which the file is
being loaded, or if the file owner runs out of spool IDs, the file is assigned to
the user who issued the SPXTAPE LOAD command.
If that user also runs out of spool IDs, the file is not loaded, and NO_LOAD is
recorded in the SEG_STAT field of the entry in the volume log.
9. During SPXTAPE LOAD processing, response 5 is issued when all data has
been read from a tape. Response 7, which is issued periodically to indicate the
command is processing, may continue to be received even after response 5
has been issued for all the tapes being processed because the files are still
being written into the spooling system. However, the command can no longer
be ended or canceled at this point.
10. If you entered SPXTAPE LOAD with the RUN option (or no disposition, which
results in a default of RUN), there is no way for SPXTAPE to know how many
tape volumes are involved in the LOAD operation. Therefore, each time logical
end-of-tape is reached, SPXTAPE issues Response 5 asking for the next
volume to be mounted. Logical end-of-tape means the end of the tape file
written by SPXTAPE DUMP on that volume.
If there are other tapes to be processed, mount the next tape. If you are using
more than one tape drive, CP continues reading on the other drives. When you
mount and ready the new tape, CP starts reading on that drive again.
If there are no other tapes to be mounted, and all tapes currently mounted
have finished processing (you have received the mount next tape response for
Chapter 2. CP Commands 1499