Operation: Excerpt from a job protocol showing the output from the LISTALC command with different operands, especially how LISTALC treats the temporary data sets.

⋮
  //JDC# JOB job card data …
  //*
  //         EXEC  PGM=IKJEFT01,DYNAMNBR=100,REGION=8M
1 //NORBERT1 DD    DSN=JDC.NORBERT,DISP=(OLD,KEEP,DELETE)
2 //NORBERT2 DD    DISP=(NEW,DELETE),SPACE=(TRK,(1,1))
3 //NORBERT3 DD    DSN=&&DSNAME,DISP=(NEW,DELETE),
  //             SPACE=(TRK,(1,1))
⋮
 IGD104I JDC.NORBERT                             RETAINED,  DDNAME=NORBERT1
 IGD105I SYS95069.T122631.RA000.JDC#.R0201039    DELETED,   DDNAME=NORBERT2
 IGD105I SYS95069.T122631.RA000.JDC#.DSNAME.H02  DELETED,   DDNAME=NORBERT3
⋮
 READY
  LISTA
 JDC.NORBERT
⋮
 READY
  LISTA STATUS
 --DDNAME---DISP--
 JDC.NORBERT
   NORBERT1 KEEP,DELETE
⋮
 READY
  LISTA SYSNAMES
 JDC.NORBERT
 SYS95069.T122631.RA000.JDC#.R0201039
 SYS95069.T122631.RA000.JDC#.DSNAME.H02
⋮
 READY
 END

Note the three JCL DD statements identifying:

1. A permanent data set named JDC.NORBERT
2. A temporary data set without DSN parameter at all (the system will specify a data set name)
3. A temporary data set with a name of &DSNAME.