Disk objects (WPDisk class, i.e. the objects in the "Drives" folder) support the following codes in addition to the codes for all objects:

$fb
  free space on drive in bytes
$fk
  free space on drive in kBytes, i.e. bytes / 1000
$fK
  free space on drive in KBytes, i.e. bytes / 1024
$fm
  free space on drive in mBytes, i.e. bytes / 1000000
$fM
  free space on drive in MBytes, i.e. bytes / 1048576
$F
  file-system type (FAT, HPFS, CDFS, ...)

Notes: If you are using these keys, you should make sure that you have OS/2's hardware error messages disabled, because otherwise you'll get a "drive not ready" message every time no disk is inserted. The new "OS/2 Kernel" object lets you do this on the "Errors" page.

Note also that the $f codes are redefined for disk objects. Normally, they display the free space on the drive on which the folder resides, which, for the "Drives" folder, would of course always return the same value for the drive on which your Desktop resides. Thus this code has been redefined for drive objects.