z/OS MVS JCL Reference
Previous topic | Next topic | Contents | Contact z/OS | Library | PDF

Additional rules for modifying DD parameters

z/OS MVS JCL Reference

The following additional rules apply for modifying DD parameters:
  • To nullify all parameters but the DCB parameter, code DUMMY on the overriding DD statement.
  • Special rules apply when overriding a DCB parameter:
    • Code only the keyword subparameters to be changed; the other DCB subparameters remain unchanged.
    • If a positional subparameter is needed, code it, regardless of whether it appears in the overridden DCB parameter. If a positional subparameter is not needed or is to be nullified, omit it from the overriding DCB parameter.
    • To nullify the entire DCB parameter, nullify each subparameter appearing in the overridden DCB parameter.
  • To nullify a DUMMY parameter on the procedure statement, code one of the following on the overriding statement:
    • A DSNAME parameter with a name other than NULLFILE
    • A SYSOUT parameter
    • A * or DATA parameter
    • A SUBSYS parameter.

Go to the previous page Go to the next page

Copyright IBM Corporation 1990, 2014