You specify HFS in the DSNTYPE parameter to allocate an HFS data set. You can also define a data class for HFS data sets. Both cataloged and uncataloged HFS data sets can reside on a single non-SMS-managed volume. A cataloged HFS data set can also be a multivolume if it resides on Storage Management Subsystem managed volumes. This type of data set can expand to as many as 255 extents of direct access storage device (DASD) space on multiple volumes (59 volumes maximum with 123 extents per volume).

RACF® or an equivalent security product must be installed and active on your system to use z/OS® UNIX or HFS data sets. z/OS UNIX maintains system security by verifying user identities and file access control information.