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

SPXTAPE
1466 z/VM: CP Commands and Utilities Reference
to add drives at any time for performance or to recover from tape drive errors.
However, if the previous command was not entered with the APPEND
operand, the command to expand the range cannot include any file selection
criteria.
7. If all the tape drives on an active SPXTAPE command are reset (using RESET,
DETACH, GIVE, or some other command), or if the issuer of the SPXTAPE
command logs off or is forced off, the effect is the same as issuing the
SPXTAPE CANCEL command for each tape drive.
8. You may specify selection criteria operands in any order. All selection criteria
specified on a command must be met for a file to be selected.
9. A user with only class E command privileges cannot process reader, printer, or
punch files.
A class G user can process only files on the user’s own reader, printer, punch,
and system trace file queues, or files on tape that were dumped from these
queues.
A class G user should not be given access to tapes containing files that belong
to other users. Although SPXTAPE does not permit the class G user to load or
scan a file that belongs to another user, there are other commands and
programs the user could use to read the contents of the tape.
10. Attention: Using multiple SPXTAPE commands to load and dump files
simultaneously is not recommended. Simultaneous SPXTAPE operations may
overlap. For example, if a DUMP PURGE request matches the selection
criteria of a file that was just loaded by a LOAD request, the file might be
dumped and purged from the system before it can be used.
If multiple SPXTAPE DUMP commands are issued simultaneously for the
same files, some files might not be dumped as many times as specified in the
commands. This is because SPXTAPE DUMP opens a file to be dumped, but
a file already open (except a named saved system or saved segment file)
cannot be dumped.
11. SPXTAPE attempts to dump or load the selected files in the minimum amount
of time by overlapping and optimizing the DASD and tape I/O activity. To
maximize performance in a DUMP operation, unless you know the files being
dumped will occupy less than one volume, it is recommended that you use at
least one tape drive for every 4-6 spool DASD volumes, with a minimum of two
(to allow overlapping volume mounting).
12. Tape-handling options (disposition operands) of LEAVE, REWIND, and RUN
(rewind and unload) are provided for the DUMP, LOAD, and SCAN operations.
The disposition is processed when the command is complete (or when the
operation is ended by an SPXTAPE END command) to position the tape for
subsequent commands. For LOAD and SCAN, the disposition also determines
what conditions cause completion of the command.
SPXTAPE rewinds and unloads the current tape and waits for another tape to
be mounted when:
v DUMP encounters either the physical end-of-tape or a permanent tape I/O
error.
v LOAD or SCAN with the RUN disposition encounters either the logical
end-of-tape (the end of the tape file written by SPXTAPE DUMP) or a
permanent I/O error.
If SPXTAPE END is issued for a tape drive that is currently active for an
SPXTAPE command with the APPEND disposition, the disposition is changed
to RUN; that is, the tape is rewound and unloaded.