Overriding attributes defined in the data class

For a new data set, you can, if needed, override the data class attributes defined in the data class for the data set by coding one or more of the following DD parameters:

RECORG (record organization) or RECFM (record format)
LRECL (record length)
KEYLEN (key length)
KEYOFF (key offset)
DSNTYPE (type, PDS or PDSE)
AVGREC (record request and space quantity)
SPACE (average record length, primary, secondary, and directory quantity)
RETPD (retention period) or EXPDT (expiration date)
VOLUME (volume-count)

For example:

  
   //SMSDS2  DD  DSNAME=MYDS2.PGM,DATACLAS=DCLAS02,DISP=(NEW,KEEP),  
   //          LRECL=256,EXPDT=1996/033

In the example, the logical record length of 256 and the expiration date of February 2, 1996, override the corresponding attributes defined in the data class for the data set.

With SMS, you can associate a data class with any new data set, (whether or not it is system-managed). If you do not specify one or more of the DD parameters listed earlier (RECORG, RECFM, LRECL, KEYLEN, and so forth), the system uses the defined data class attributes.

For an existing system-managed DASD data set, note that you cannot use the volume-count subparameter to override the current volume count. (If you use the subparameter, the system ignores your specification and uses the current volume count.)