function FormatByteSize(const bytes: Double): string;
const
 B = 1;
 KB = 1024 * B;
 MB = 1024 * KB;
 GB = 1024 * MB;
begin
 if bytes > GB then
  result := FormatFloat('#.## GB', bytes / GB)
 else
  if bytes > MB then
   result := FormatFloat('#.## MB', bytes / MB)
  else
   if bytes > KB then
    result := FormatFloat('#.## KB', bytes / KB)
   else
    result := FormatFloat('#.## bytes', bytes) ;
end;
 
//kullanımı
procedure TForm1.Timer1Timer(Sender: TObject);
var
  disk_seri_no,disk_yolu : string;
var
 Source, Target : string;
var
 freeSpace, totalSpace: Double;
 s: Char;
 surucu:string;
begin
disk_yolu:=ExtractFileDrive(Application.ExeName)+'';
dxRibbonStatusBar1.Panels[1].Text:=disk_yolu;
disk_seri_no:=FindVolumeSerial(pchar(disk_yolu));
dxRibbonStatusBar1.Panels[3].Text:=disk_seri_no;
edit1.Text:=ExtractFileDrive(Application.ExeName);
Source := edit1.Text;
Target := Copy(Source, 0, 1);
edit1.Text:=Target;
 // Drive letter
 // Laufwerksbuchstabe
surucu:=edit1.Text;
 s:=surucu[1];
 freeSpace := DiskFree(Ord(s) - 64);
 totalSpace := DiskSize(Ord(s) - 64);
 dxRibbonStatusBar1.Panels[9].Text := Format('%S', 
[formatByteSize(freeSpace)]);
 dxRibbonStatusBar1.Panels[5].Text := Format('%S', 
[formatByteSize(totalSpace)]);
 dxRibbonStatusBar1.Panels[7].Text:= '%'+IntToStr(Round((totalSpace - 
freeSpace) / totalSpace * 100)) +' Kullanımda.';
end;