DosVersion function

  DECLARATION:  DosVersion

      PURPOSE:  Returns the DOS version number

         UNIT:  DOS

  RESULT TYPE:  Word

      REMARKS:  The low byte of the result is the major version number,
                the high byte is the minor version number.

      EXAMPLE:  Uses
                   DOS;

                Var
                   Ver : Word;

                Begin
                   Ver := DosVersion;
                   Writeln('This DOS version is ',Lo(Ver),'.',Hi(Ver));
                End.