Int 2F Fn C300  U - Spacemanager - Installation Check                      [d]

   AX = C300h
   DX = 0000h

Return: AL = FFh if any SpaceManager programs installed
       BX = 6F73h
       CX = 6F68h
Program: SpaceManager is an enhancement for MS-DOS DoubleSpace by Vertisoft
     Systems, Inc.

Note:  AH=C3h is the default; SpaceManager programs scan from C3h to FFh for
     a free multiplex number

See Also: AX=C300h/DX=0666h