TMF Reference Manual (G06.26+)

TMFCOM Tape Media Considerations
HP NonStop TMF Reference Manual—522418-003
4-3
Additional Guidelines for Using Tape Media
The ALTER TAPEMOUNT command may be used to choose tapes from either
set for input.
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If the copies were made in series, however, they are interchangeable on the
first reel only. Thus, if you use the first reel from Set A, the ALTER
TAPEMOUNT command cannot be used to choose a reel from Set B. To
switch sets, you must reject the current request and start over again, using the
correct set throughout.
ALTER TAPEMOUNT can only be issued by members of the super user group.
If the status of a TMF scratch tape changes to BAD while a mount request is pending
for that tape, a subsequent MEDIACOM tape-mount request results in an error. To
work around this situation, enter a REJECT command to reject the mount request.
For more information about using the MEDIACOM labeled-tape-processing
commands, including syntax rules and usage guidelines, see DSM/Tape Catalog
Operator Interface (MEDIACOM) Manual.
For information about the causes and corrections of common problems that can occur
with your tape subsystem, see the discussion of labeled-tape operations in Guardian
User’s Guide.
Additional Guidelines for Using Tape Media
Additional guidelines for using tape volumes and drives follow.
Monitoring the Tape Drives
When a defective tape volume is mounted, the tape drive transmits an error message
and waits for the operator to mount a new tape or abort the tape request. Even with an
autoloader, an operator might have to intervene−the autoloader might not automatically
flush a defective tape and make a new tape available to the requesting application.
Instead, the autoloader might hang while unattended, and the application would wait
indefinitely until someone loaded a correct tape. In all time-critical operations, an
operator should monitor the tape drives to ensure that this condition does not prevail.
Always verify that pre-mounted TMF scratch tapes are not write-protected. If the first
tape mounted in response to a mount request for a scratch tape is write-protected,
TMF still requires that particular tape volume even though it cannot be used. This is
particularly troublesome when multiple TMF scratch tapes have been pre-mounted on
a multi-tape device, especially a silo device; in such a case, all remaining scratch tapes
will be rejected and unloaded. To correct the problem, you must either remove the
write protection from the original tape, or reject the request and start over with a tape
that is not write-protected.