program ENUFDISC { www.merlyn.demon.co.uk  >= 2002-06-21 } ;

uses Dos ;

var DF, Min : longint ; N : integer ; D : byte ; S : string [3] ;

BEGIN ;
s := ParamStr(1) ;
if S='/?' then begin Writeln('ENUFDISC [drive [Minimum]]') ; HALT end ;
D := 0 ;
if ParamCount>0 then begin
  S[1] := UpCase(S[1]) ;
  if S[1] in ['A'..'Z'] then D := Ord(S[1]) - Ord(Pred('A')) else begin
    Val(ParamStr(1), D, N) ;
    if N<>0 then begin Writeln('Param 1 error!') ; HALT end ;
    end ;
  end ;
DF := DiskFree(D) ;
if (DF>=0) and (ParamCount>1) then begin
  Val(ParamStr(2), Min, N) ;
  if N<>0 then begin Writeln('Param 2 error!') ; HALT end ;
  DF := Ord(DF>=Min) ;
  end ;
Writeln(DF) ;
END.

With no parameter, returns free space on default disc.
With one parameter, returns free space on that disc; 0 = default,
  1.. or a.. or A.. is drive A...
With a second parameter Minimum, returns 1 if that much is free, else 0.
Result to standard output; can use STOW to environment,
Max number is 2^31-1; truncated if free space is bigger.
An inoperable or non-existent drive gives -1.