DSM/Tape Catalog User's Guide
DSM/TC Tape Processing
DSM/Tape Catalog User’s Guide — 520233-008
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Substituting Scratch Tapes
Substituting Scratch Tapes
To request scratch tapes, use a DEFINE request with the VOLUME attribute. You can
request them generically with VOLUME SCRATCH or specifically by their names, such
as VOLUME (B34, B59, C60). In some cases, DSM/TC or an operator substitutes a
different scratch tape for the one originally requested. A tape can be a scratch tape or,
if the label type is BACKUP, a partially filled appended tape.
Using VOLUME SCRATCH
When VOLUME SCRATCH is used to request a scratch tape, DSM/TC chooses a tape
from the pool you designate in the DEFINE. In the simplest case:
1. $ZSVR asks DSM/TC to choose a scratch t
ape from the pool.
2. DSM/TC chooses a tape and reserves it and sends the t
ape name back to $ZSVR.
3. $ZSVR issues a mount message for the t
ape name it received.
4. $ZSVR determines which drive the tape is on.
5. $ZSVR connects the tape drive to the application.
Any cataloged scratch tape from the same pool can satisfy a VOLUME SCRATCH
request after the mount message is issued for a particular tape. Assume you request
an output tape with this DEFINE:
10> ADD DEFINE =OUTFILE, CLASS TAPECATALOG,
10> & LABELS ANSI,&
10> & VOLUME SCRATCH,&
Table 3-1. Substituting Scratch Tapes
Tape
Requested By DSM/TC Action
Mount Message
Issued Operator Action
VOLUME
SCRA
TCH (or
no volume
specified)
Chooses a scratch
tape from pool in
DEFINE
For tape
DSM/TC chose
Mounts scratch tape named
in mount message or
substitutes any scratch tape
from pool in DEFINE.
VOLUME (tape
na
me)
Verifies tape name For tape named
by VOLUME
Operator must mount tape
named in mount message or
use ALTER TAPEMOUNT to
ask DSM/TC to substitute
another scratch tape from
pool in DEFINE.
VOLUME (tape
na
me)
Cannot verify tape
name; goes to next
specified tape name. If
none, substitutes a
scratch tape from
same pool in DEFINE
For tape
substituted by
DSM/TC, not the
tape named in
VOLUME
Operator must mount tape
named in mount message or
use ALTER TAPEMOUNT to
ask DSM/TC to substitute
another scratch tape from
pool in DEFINE.