DSM/Tape Catalog User's Guide

DSM/TC Tape Processing
DSM/Tape Catalog User’s Guide — 520233-008
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Using VOLUME (Tape Name)
pool designated in the DEFINE and reserves it. If another tape name is in the list
and passes verification, it is reserved.
2. $ZSVR issues a mount message for the substituted tape name received from
DSM/TC and then connects the tape drive to the application after it determines
which drive the tape is on.
To ensure your VOLUME volume set is used, you must instruct the operator to
physically set the tapes aside before the application runs. The operator should reject or
change any mount messages for your volume set from other applications with REJECT
TAPEMOUNT or ALTER TAPEMOUNT commands.
If you do not instruct the operator to reserve your tapes, the operator might use:

Some or all of the tapes you named, but not in the order you gave them in the
VOLUME attribute.

None of your tapes, because they no longer had a status of scratch in the volume
catalog when DSM/TC tried to verify them. DSM/TC substituted other tapes for all
of your tapes.
Examples

This example illustrates an automatic substitution of a scratch tape by DSM/TC.
This DEFINE names two scratch tapes for an output tape file:
32> ADD DEFINE =WRITE_LARGE_FILE, CLASS TAPECATALOG,&
32> & USE OUT,&
32> & POOL TEST_TAPES,&
32> & LABELS ANSI,&
32> & FILEID TEST_DATA_92,&
32> & VOLUME (A20, A45),&
32> & RECFORM FIXED,&
32> & RECLEN 1024,&
32> & BLOCKLEN 28672
DSM/TC discovers that tape A20 is not a scratch tape when it verifies its status,
making it unavailable for use. DSM/TC checks the status of the second tape, A45,
and finds it is a scratch tape. Subsequently, the operator is asked to mount A45 as
the first tape for the job, which the operator does.
The application begins writing TEST_DATA_92 to A45. When it needs a second
tape, DSM/TC is again requested to locate a scratch tape. Because no more tapes
named by VOLUME remain, DSM/TC chooses scratch tape TT80 from the pool
TEST_TAPES. At the completion of the job, TEST_DATA_92 is written to tapes
A45 and TT80, instead of A20 and A45.
Note. When scratch tapes are named by the VOLUME attribute, the operator must mount the
tape named in the mount message. If the operator needs to substitute another tape after the
mount message is displayed, an ALTER TAPEMOUNT message must be executed.