13 January 2006

A pound of directories from about the FAT?

Microsoft are crowing about having patented the FAT filesystem, but like ShysterShylock from The Merchant of Venice, who was allowed his “pound of flesh taken from about the heart” from his debtor Antonio, but (as Portia pointed out) was not allowed any blood along with it, the patents don’t actually cover FAT itself, they only cover FAT32 and VFAT.

FAT itself is derived directly from CP/M’s braindead filesystem. It even has a directory layout with scars from CP/M’s FCBs (File Control Blocks, the in-memory representation of an open file). Except for the fact that the FAT32 extension seems “novel” and “non-obvious” to some lame-brain in the USPTO, I would have said that FAT itself is essentially not patentable.

Microsoft claim that they developed FAT for a standalone BASIC in 1976, but with its obvious CP/M heritage, it was not noticeably different from all of the other random filesystems floating around at the time, and Seattle Computer Systems (of QDOS fame) evidently didn’t have a problem with having built their own version of it (the descendants of which are today’s FAT code, since Microsoft eventually bought QDOS and renamedre-engineered it as MS-DOS).

On top of this, the much younger VFAT extensions have unquestionable prior art in filesystems like UMSDOS and Rock Ridge, which operate in an essentially indistinguishable fashion to provide long filenames and ownership information on short-filenamed and essentially attribute-free underlying filesystems (FAT and ISO9660, respectively).

So what devices are covered by the patents?

Anything which uses the VFAT extensions (practically nothing in the way of digital cameras and such) or the 32-bit version of FAT (practically everything with a worthwhile amount of storage).

That shouldn’t be much of a problem outside of the USA, since relatively few other patent offices are stupid enough to award such obvious and pre-empted patents.

VFAT is easy to work around, too. Since it’s been designed to be backwards compatible with FAT, files on a VFAT partition can simply be read and written under their 8.3 “real name”. FAT32 is harder.

Where the fan gets turned into a sewage pump is in the area of licensing.

The GPL prohibits the distribution of patent-encumbered code. Where I live, a VFAT32 filesystem is not covered by patents, and if the local patent office ever tries to be that stupid, we’ll simply nuke ’em with a trust Rusty. However, they are so encumbered in the USA.

What consequences for the GPL?

If you’re prevented from distributing code because it’s patented somewhere, all Microsoft needs to do is “buy” some little island nation and patent everything under the sun there. However, if the solution were so simple, they would already have done it. It’ll be interesting watching the luminaries sort this one out.

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