//ddname DD ACCODE=access-code,...
The system must contain an installation-written file-access exit routine. This routine verifies that the ACCODE parameter specifies the correct code for an existing data set and, therefore, can use a data set.
//DD1 DD DSNAME=NEWDS,ACCODE=F,LABEL=(,AL),UNIT=3380,
// VOLUME=SER=998877,DISP=(NEW,CATLG,KEEP)
//DD2 DD DSNAME=OLDDS,ACCODE=J,LABEL=(,AL),UNIT=3380,
// VOLUME=SER=665544,DISP=OLD