Int 21 Fn 4412  - Dr-dos 5+ - Determine DOS Type                           [O]

   AX = 4412h
   CF set

Return: CF set if not DR-DOS
       AX = error code (see AH=59h)
   CF clear if DR-DOS
       DX = AX = version code (see AX=4452h)

Note:  this obsolete call which will not be supported in future versions of
     DR-DOS is identical to AX=4452h

See Also: AX=4452h