Before a user can log on to TSO/E, you must define that user to TSO/E. You do this by storing information about the user in the UADS or the RACF® data base.

You can use the RACF data base only if your installation is using RACF. If your installation is using RACF, you can use the UADS only, the RACF data base only, or both. Even if you use only the RACF data base, z/OS requires that you keep the UADS cataloged unless you have customized MVS™ to eliminate this requirement.

For information about defining users, see Maintaining the UADS, RACF data base, and broadcast data set.