You can dynamically allocate a data set if the data set name exists and is cataloged. The catalog containing the entry must have a name or alias that matches one or more of the qualifiers of the qualified data set name. All referenced catalogs must be connected to the system master catalog.

Access method services does not support the S99TIOEX, S99ACUCB, and S99DSABA options of dynamic allocation. These three options are called the XTIOT, UCB nocapture and DSAB-above-the-line options. This restriction applies to the required SYSIN and SYSPRINT data sets and to the DD names that are identified by keywords on the commands.

This restriction does not apply to data sets that are handled by the user routines that are described in User I/O Routines.

Access method services dynamically allocates VSAM and non-VSAM data sets with a disposition of OLD.

To dynamically allocate a volume, the volume must already be mounted as permanently resident or reserved. You should carefully consider the PRIVATE and PUBLIC use attributes when you mount a volume.