Re: OT?: FAT32(/16?) Question: Max. files in top level

[<tomas@tuxteam.de>]

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On Thu, Dec 29, 2016 at 07:38:18AM +0100, Xen wrote:
> doark@mail.com schreef op 26-12-2016 3:41:
> 
> >I encountered this many times on windowz FAT32 in a non-root dir, but
> >never on Linux. I suspect that it was/is one of their "Features". The
> >said "Feature" still was there when using ntfs in XP if I remember
> >correctly.
> 
> Perhaps it's just because Windows Explorer doesn't deal well with
> many files. Try to unpack some open source archive of some
> distributor that had to make their sources open, some 1G archive,
> and see how it goes. Not recommended :p.
> 
> Then when you've unpacked it, deleting it takes a few years as well.
> So imposing a filesystem limit may just have been a way to ensure
> that their user interface limit is not quickly reached, I don't
> know.

Calculemus, as Leibnitz said. A bit of experimental informatics:

  dd if=/dev/zero of=dose bs=4096 count=64
  mkfs.vfat dose
  sudo mkfs.vfat dose
  sudo mount dose /mnt
  for i in $(seq 1 10000) ; do sudo touch /mnt/f.$(printf "%05d" $i) || echo "fail $i" ; done

The loop starts failing at i == 257 with "no space left on device"
(that's ENOSPC if I remember correctly). The "device" has still
reams of space left:

  tomas@rasputin:~$ df -h
  Filesystem                 Size  Used Avail Use% Mounted on
  [...]
  /dev/loop0                 238K     0  238K   0% /mnt

So 256 must be a limit on number of entries on the top level dir of
FATty file systems (or an implementation limit of Linux's version
of that, but guess whom I trust more to bust that badly).

Try this at home. Enjoy.

- -- t
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