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Common Command Options › Specifying Data Set Names › Using Generation Data Groups (gdg Option)

Using Generation Data Groups (gdg Option)

You can create multiple generations of a single data set name using a GDG. You might want to do so if you run the same job frequently and want to store each iteration of the resulting data under the same data set name.

The option that lets you work with generations of a data set name is gdg. The following table lists values for gdg based on the task you are trying to perform.

To do the following:

gdg value:

Create a new generation of a data set name

+1

Make an existing data set name part of a GDG

+1

Specify that CA VM:Tape is to use the most recent generation of a data set name

0

Specify that CA VM:Tape is to use the generation of a data set name that is n generations before the most recent generation

-n

When a data set name is part of a GDG, CA VM:Tape appends the qualifier .GnnnnVnn to the data set name. Gnnnn is the data set name’s generation number. For example, MONTHLY.DATA.G0003V00 is the third generation of the MONTHLY.DATA data set name in a GDG. Because .GnnnnVnn contains nine characters, data set names that belong to GDGs can include only 35 characters rather than 44.