Int 2F Fn 12FF  U - Novell Dos 7 - Set ???                                 [O]

   AX = 12FFh
   BX = 0009h
   DX = new value for ???

Return: ???

Note:  the DX value is stored at offset 66h in SYSVARS and offset 18h in
     the Novell DOS 7 internal variable table