Int 2F Fn A900  - Metztsr.com - Installation Check                         [U]

   AX = A900h
   CF set

Return: CF clear if resident
       AX = 97FFh
   CF set if not present

Notes: METZTSR.COM prevents METZ applications (such as the MAGIC screen
     saver) inactivity timeout while running a DOSapp under MS Windows.
   the default multiplex number is A9h, but may be set to any value from
     80h to FFh with a commandline switch

See Also: AX=A901h,AX=A902h