Files in a z/OS file system can be used for input and output, but are only supported by the Blockset technique. If Blockset is not selected for a DFSORT application that uses z/OS UNIX files, DFSORT will issue an error message and terminate.

You should be familiar with the information found in z/OS UNIX System Services User's Guide regarding z/OS UNIX files if you use them. DFSORT uses BSAM to access z/OS UNIX files and is thus subject to all of the capabilities and restrictions that entails, as described in z/OS DFSMS Using Data Sets.