MICROSOFT AND FAT PATENTS

11 Jan 2006

Recently, a thread on the FreeDOS mailing lists asked about Microsoft
and their patent for FAT:

    Slashdot has an article "Microsoft FAT Patent Upheld"
    http://yro.slashdot.org/article.pl?sid=06/01/11/0555252&tid=155&tid=109

    The discussion also links to the page "FAT File System Technology
    License" http://www.microsoft.com/mscorp/ip/tech/fat.asp

    Does anyone know if this is a problem for FreeDOS or not? The
    linked page about FAT license only speaks about using FAT on a
    media, and not about products using FAT.

This has been asked by several people in different forums. The page
that was mentioned (http://www.microsoft.com/mscorp/ip/tech/fat.asp)
is the important one. As I understand it, the impact will be to
manufacturers of devices. Specifically mentioned in the Microsoft page
are:

    * A license for removable solid state media manufacturers
    * A license for manufacturers of certain consumer electronics devices

--

Update: I started looking more into the patents in question, and I'm
not really concerned with respect to FreeDOS. The 3 patents listed on
http://www.microsoft.com/mscorp/ip/tech/fat.asp are:

    * U.S. Patent #5,579,517 Common name space for long and short filenames
    * U.S. Patent #5,758,352 Common name space for long and short filenames
    * U.S. Patent #6,286,013 Method and system for providing a common
      name space for long and short file names in an operating system

The abstracts for each look identical:

    "An operating system provides a common name space for both long
    filenames and short filenames. In this common namespace, a long
    filename and a short filename are provided for each file. Each
    file has a short filename directory entry and may have at least
    one long filename directory entry associated with it. The number
    of long filename directory entries that are associated with a file
    depends on the number of characters in the long filename of the
    file. The long filename directory entries are configured to
    minimize compatibility problems with existing installed program
    bases."

None of these are directly related to FAT, per se. They are more
directly related to VFAT and LFN support. IANAL, but this doesn't look
very applicable to FreeDOS sans LFN.

--

Update: If true, this could be an issue for FreeDOS, but I understand
it is already being contested. I'm taking a "wait and see"
approach. The GNU GPL is quite clear with respect to patents. In
section 7, it says:

    7. If, as a consequence of a court judgment or allegation of
       patent infringement or for any other reason (not limited to
       patent issues), conditions are imposed on you (whether by court
       order, agreement or otherwise) that contradict the conditions
       of this License, they do not excuse you from the conditions of
       this License. If you cannot distribute so as to satisfy
       simultaneously your obligations under this License and any
       other pertinent obligations, then as a consequence you may not
       distribute the Program at all. For example, if a patent license
       would not permit royalty-free redistribution of the Program by
       all those who receive copies directly or indirectly through
       you, then the only way you could satisfy both it and this
       License would be to refrain entirely from distribution of the
       Program.

The "For example" is the case that could affect FreeDOS. If Microsoft
decides to charge a royaltee for use the FAT technology in operating
systems, (and they haven't, yet) then FreeDOS could not use it. Since
FAT is pretty much a requirement for DOS, that would be a big problem
for FreeDOS. For now, though, we are probably safe. Microsoft seems to
intend to apply the patent for the FAT technology as it applies to
manufacturers of devices.