DOS Unit
                            File Mode Constants

     These constants are used by the file-handling procedures when opening
     or closing disk files.  The mode fields of the file variables will
     contain one of the following values:

                              fmClosed   = $D7B0;
                              fmInput    = $D7B1;
                              fmOutput   = $D7B2;
                              fmInOut    = $D7B3;