Manual

Configuring DSM/TC

DSM/Tape Catalog User’s Guide — 520233-008

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Default Abend Retention

Abend retention is the number of days past the creation date to keep a catalog entry

for an incomplete tape file. (An incomplete tape file is created when an application

abnormally ends while writing data to a tape.) The default value is 1 day. To change the

default:

> MEDIACOM ALTER MEDIADEFS, ABENDRETENTION

HP recommends that you set the same abend retention, support level, and retention

period values on all nodes.

System Search List

The system search list is used to define what systems are within the DSM/TC system.

When system names are added to the system search list, DSM/TC is expanded to

include those systems. All the systems in the system search list are treated as one

entity by DSM/TC. Once the systems that are sharing DSM/TC are determined, the

system search list on each system is configured to include the appropriate systems.

To establish the system search list:

> MEDIACOM ALTER MEDIADEFS, SSLIST

Data Compression

DSM/TC supports IBM IDRC data compression. When activated, compression lets

various tape drives that support compression write multiple times the normal amount of

data on a cartridge tape.

There are four classes of tape drives:



Drives that do not support compression (for example, models 517x)



Drives that do not support software control of compression (for example, model

5194; compression is always on)



Drives that support software control of compression (for example, model 5190)



Drives that support software control of compression, but have a hardware override

control (for example, model 515x (DLT) tape drives)

For drives that support software controlled compression, compression is set in this

order of precedence, from highest to lowest:



For unlabeled tapes, the SETMODE 162 setting, if issued by an application while

the tape is positioned at BOT



The CLASS TAPECATALOG define COMPRESSION setting



If Labeled Tape Support is enabled, the MEDIACOM MEDIADEFS setting (set

using the MEDIACOM ALTER MEDIADEFS command)