//ddname DD SYSOUT=(class,diskette-writer),DSID=id
//ddname DD SYSOUT=(class,diskette-writer),DSID=(id,V)
A system command, from the operator or in the input stream, must start the diskette writer before the DD statement is processed.
For more information on the 3540 diskette, see 3540 Programmer's Reference. For information on external writers, see z/OS JES2 Initialization and Tuning Guide or z/OS JES3 Initialization and Tuning Guide.
//EX7 DD SYSOUT=(W,WRT3540),DSID=MYDS5