The maximum number of generation data sets, up to 255, in a GDG.
The disposition of the data set in the catalog.
The required attributes for a generation data group data set. A generation data set is one of a collection of successive, historically related, catalogued data sets that together are known as a generation data group (GDG). Use this structure when you want to import a GDG. For more information on GDG, see Generation data sets.