If your installation is running SMS, you can use a data class with a non-system-managed data set, such as a tape data set. The DCB information defined in the data class is used as the default. If you do not use a data class, you need to supply in the JCL, or in the program, the DCB information such as LRECL and RECFM, and the DSORG. You cannot use data class if your installation is not running SMS.