Memorex LOCK - VERSION 2-24 Especificaciones descargar pdf (Pagina 234)

Multi-Dataset Processing Processing Tape Datasets

7-14 User Reference

Multi-Dataset Processing

This section explains the concept of multi-dataset groups and describes their processing

requirements and options.

A multi-dataset group consists of a prime dataset and up to 9,998 subdatasets. A multi-dataset

group can reside on a single volume or on multiple volumes.

All datasets participating in a multi-dataset group MUST

conform to standard dataset format

as defined by LIOCS (Logical Input Output Control System). Standard dataset format is

comprised of three components, each followed by a tape mark:

•

Header label set

• Data

• Trailer label set

Nearly all programming languages and utility programs create datasets which conform to

standard format.

Datasets known not to conform to standard data format are those created by the LIBR program

BACKUP function and the IDCAMS program BACKUP function. Datasets created by these

functions insert additional tape marks among the data component records thereby making it

impossible to properly position a volume to any subsequent subdataset.

The first dataset on the first reel of a multi-dataset group is called the prime dataset. The

prime dataset "owns" all the volumes in the group and controls their physical attributes.

All the datasets that follow the prime dataset in the group are called subdatasets. Subdatasets

must be associated with the prime dataset. BIM-EPIC supports two methods for this:

• Automatically (using the DSN Catalog)

•

Explicitly (using JCL)

If the datasets are associated using TLBL statements, the length of the prime dataset name is

limited to 17 characters, although the subdataset names are not limited. This type of

association is made by specifying the prime dataset name when the subdataset names are

controlled.

If the datasets are associated using DD statements, the length of the prime dataset name can be

up to 44 characters. This type of association is made by a referback to the prime dataset name

on the DD statement for the subdataset. Therefore, a DD statement for the prime dataset name

is necessary when the subdataset is created. This method allows the additional flexibility of

associating the same subdatasets with different prime datasets depending on job requirements.

Description

WARNING!

Prime Datasets

1 2 ... 229 230 231 232 233 234 235 236 237 238 239 ... 488 489

Sin comentarios

Memorex LOCK - VERSION 2-24 Especificaciones Pagina 234