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Introduction

Chapter 12. Managing Tape Volumes 12-3

You can use tape pooling to group similar types of tapes into tape pools. For example, your

high quality tapes could constitute one pool, short tapes another, long tapes a third, and so

forth. You can also use pools to separate cartridge tapes from reel tapes. Datasets are

assigned to tape pools through the DSN Catalog. When a pooled dataset is created, BIM-

EPIC automatically requests the operator to mount a scratch tape from the appropriate pool.

Tape pools are established using the TSIDPOL macro and BIM-EPIC configuration options.

Each pool is given a one character pool code (A to Z or 0 to 9) and is assigned one or more

volume serial number ranges.

If a tape's volume serial number falls within a pool's ranges, the tape belongs to that pool. A

pool tape can only be used to write datasets assigned to that pool. If a volume serial number

does not fall in any of the defined ranges, the tape is not a pool tape. It can only be used to

write datasets that are not assigned to a tape pool.

Datasets can be assigned to tape pools through the Online Manager, the TSIDMNT program,

or the use of the OPTION=TPL=x parameter on a DD statement.

The tape ownership feature provides another form of tape pooling. An owner ID is a two

character code that is used as the first two characters in a tape's volume serial number.

When a dataset is cataloged with an owner ID, it can only be written on tapes with volume

serial numbers which begin with the code specified.

Tape ownership is different from tape pooling because a pool tape can only be used for

datasets assigned to that pool. Tape ownership does not restrict the use of tapes in that way.

Only the dataset is restricted. The tape can be used for any dataset.

You can restrict datasets to small or large tapes with the size specification feature.

Small tapes are distinguished by their volume serial numbers, which must end with S. Large

tapes have no restrictions to their volume serial numbers. You can designate that a dataset

should be written to small tapes with online or manual catalog maintenance, using the Tape

Size field.

In some cases, you may want to use a specific set of tapes for a dataset, such that all versions

of that dataset are contained on that set of tapes only.

The TSIDMNT CATALOG command contains a parameter (REV) that allows you to define

revolving datasets.

Specifying REV=YES for a dataset establishes an exclusive relationship between the dataset

and the tapes it uses: a revolving tape can only be used to write its own dataset, and a

revolving tape dataset can only be written on its own tapes.

Tape Pooling

Tape Ownership

Specifying Tape

Size

Revolving Tape

Datasets

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Memorex LOCK - VERSION 2-24 Spezifikationen Seite 361