By default, RACF® expects a data set name to consist of at least two qualifiers, with the high-level qualifier either a RACF-defined user or group ID. Single-qualifier data set names, especially for DASD data sets, affect your ability to manage or protect your data sets. For example:

• Data set name filtering is less usable for selecting data sets to be processed.
• DFSMSdss definitions of discrete data set profiles fail due to lack of correct prefix information.
• Your installation has trouble protecting the temporary data set names that DFSMSdss uses.