[ros-dev] Patent on FAT

Mark Tempel mtempel at visi.com
Fri Jan 13 21:49:42 CET 2006

He is absolutly correct (from my reading of the patents).

If you want to be free of the patent, and support long filenames, you just need
to store the long filename information in a manner that MS has not patented.

This could be done by several means (like a hidden file with the mapping in each

You can still keep the short file name DIRENTs on the filesystem.  This will
allow you to write data to a fat partition that can be read by Windows (with
only short file names) and read by Ros (short and long file names).

As to paying MS $0.25 for each download I would worry that the act of paying MS
is the same as admitting that ROS agrees that the patents are valid.  That, I
would guess, could make it hard to claim otherwise in court.

I'm not a lawyer so take that with a large grain of salt.


Quoting James Tabor <jimtabor at adsl-64-217-116-74.dsl.hstntx.swbell.net>:

> Hi all,
> I think this is important to share to the discussion. From one of the
> developers
> with FreeDOS, Eric Auer.
> Thanks,
> James
> -------- Original Message --------
> Subject: [Freedos-user] re: FAT and other file systems
> Date: Fri, 13 Jan 2006 17:16:34 +0100 (MET)
> From: Eric Auer <eric at coli.uni-sb.de>
> Reply-To: freedos-user at lists.sourceforge.net
> To: freedos-user at lists.sourceforge.net
> Hi James,
> > > And I think it is not more difficult to write HFS or FFS in the kernel
> > > of FreeDOS than ReiserFS or XFS or all the other candidates.
> I would like to comment this as follows: The Linux kernel modules for
> ext3+jbd take 131+59k of memory. Reiserfs takes 243k (243*1000 bytes,
> too lazy to convert to units of 1024 bytes). On the other hand, FAT
> core takes 38k and you use it with either MSDOS (8k) or VFAT (13k)
> implementations. Only the VFAT (long file name enabled) module of
> Linux is affected by the 3 MS patents mentioned on the MS homepage.
> > There is no way around this, unless someone will write a disclaimer,
> "Before
> > you install FreeDos, do you want to enable Fat32 Patented Features"?
> Microsoft WANTS you to believe that they patented FAT32.
> Actually they patented their clever but twisted way to store
> short and long filenames in the same directory, in a way which
> allows LFN-unaware operating systems to use the drive without
> getting confused by the LFN data and usually also without
> damaging the LFN data either. But you already point that out yourself:
> > We are
> > facing the same issue with Ros. When I use FreeDos, I use the basic 8.3
> > file system, so I don't see that as a major problem. The point here is the
> > patent is about LFN, basic 8.3 is not effected.
> So the disclaimer would only be displayed when you install the DOSLFN
> package: "Install DOSLFN, which might have patent issues?". FreeDOS as
> a DOS operating system itself is not affected by that problem. Plus
> MS does have a disclaimer about their licensing, too:
> http://www.microsoft.com/whdc/hwdev/download/hardware/fatgen103.pdf
> which is more than 5 years old by now...
> allows you to be compatible to all their FAT (including LFN) stuff
> for the purpose of booting, OS installation, diagnosis, firmware,
> similar things. They also tell that making/installing operating
> systems may use all aspects of FAT. You could see this in a pessimist
> way (you are allowed to develop and compile your OS on a LFN enabled
> host system) or in a more optimistic way (your operating system
> itself is allowed to use LFN because it simply is an operating system).
> MS is targetting two groups at the moment: Vendors of USB sticks who
> preinstall files on their sticks, and vendors of cams and mp3 players
> and similar devices. FreeDOS is neither of those. But I did notice
> that my hardware mp3 player does not support LFN. It only shows the
> id3 text, if available, as "long song name", and is limited to
> showing the SHORT file name as song name otherwise. Looks like
> the vendor of the player did not want to pay MS for each device.
> Digicams have similar issues - they usually generate filenames
> like dsc0815 dot jpg and store all extra "title/name" information
> inside the file (jpeg comment, EXIF data...?).
> Eric
> PS: I assume that you mean ReactOS, the free open WinNT clone,
> when you mention Ros. ReactOS without LFN would not be the same...
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