DSM/Tape Catalog User's Guide

DSM/Tape Catalog User’s Guide — 520233-008
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3 DSM/TC Tape Processing
This section addresses various aspects of selecting and using magnetic tapes:
Levels of Tape Processing Support
To configure a NonStop Kernel node for a specific level of tape support, use the LEVEL
option of the MEDIACOM ALTER MEDIADEFS command. The seven levels of tape
support vary from minimum tape processing services at the lowest level to maximum
services at the highest level.

If you use a third-party tape management system in parallel with
DSM/TC, the support level must be INTEGRATED.

If you use a third-party tape management system alone, the support
level must be TPTM or TPTMCOMPATIBLE.
You cannot change the support levels if any tape requests are outstanding or if any
tape drives are currently in use. For descriptions of the support levels, see Support
Level on page 5-6.
Most likely the tape level support you need to configure at first is COMP
ATIBLE. Use
this temporary level during the time your site is converting to DSM/TC.
If you always stay at the COMP
ATIBLE level, applications using TAPE DEFINEs can
request cataloged tapes without the knowledge of DSM/TC. For example, a cataloged
tape that contains an unexpired file could be requested for output by a TAPE DEFINE.
If the operator mounts the tape with a write-enabled ring, the application can write over
the unexpired file. Also, DSM/TC does not protect uncataloged tapes and tape files.
After all existing tapes and tape files are manually cataloged and all TAPE DEFINEs
are converted to TAPECATALOG DEFINEs, the tape level is changed to LEVEL
MEDIACAT using the MEDIACOM ALTER MEDIADEFS command.
The MEDIACAT level provides the highest protection of tapes and tape files and is
usually a site’s normal tape processing level once all users have converted to
TAPECATALOG DEFINEs to request tapes. The only disadvantages at this level are
that tape requests are rejected if a file catalog or volume catalog cannot be read and
DSM/TC cannot function if TMF is not running. These most likely arise during an
Topic Page
Levels of Tape Processing Support 3-1
Labeled Tapes 3-2
Volume Set 3-2
DSM/TC Interaction With $ZSVR 3-9
Status Changes in a Volume Catalog Entry 3-11
Premounted Output Tapes 3-12
Substituting Scratch Tapes 3-13