DSN: Specify the Name of the DSCB

DSN=addr

Supplies the address of a 44-byte data set name of the DSCB to be accessed.

DSN is required if ACCESS=READ or WRITE and the request is to read or write a DSCB. If a 140-byte DSCB is specified:

CVAF validity checks the storage location, but ignores the contents of the location.
Specify an argument that points to an extent within the VTOC.