FAT Patent Review May Threaten Linux Foundation

UPDATED: The Patent Office's recent review of Microsoft's file system could put Linux and other GPL-licensed products at risk, warn industry figures.

Worries over intellectual property can make for strange bedfellows. In the case of Microsoft Corp.s nearly ubiquitous FAT (file allocation table) file system, its Microsoft and the Linux community.

The open-source community has an enormous interest in the outcome of last weeks decision by the United States Patent and Trademark Office to re-examine the patent Microsoft holds on the FAT file system, a format used for the interchange of media between computers and digital devices.

The FAT file system, which Microsoft claims it first developed in 1976, has become the ubiquitous format used for interchange of media between computers and, since the advent of flash memory, also between digital devices.

On the other hand, some disagree that Microsoft was the developer of the FAT file system.

"The FAT filesystem was not first developed by Microsoft in 1976. It was developed by Seattle Computer Products in around 1979. In 1980, Microsoft licencedsome rights to the QDOS operating system from Seattle Computer Products, and distributed the rebranded QDOS as MSDOS. In 1976, Microsoft was (at best) distributing their BASIC language on paper tape; Digital Researchs CP/M operating system was the Disk OS, and it used a filesystem designed, built and owned by them," one reader told eWeek.

Another reader agreed, saying that FAT predated Microsoft. "FAT32 is based on FAT16 which in turn is based on FAT12. So we have Microsoft claiming to have created a product that was part of the original DOS system they purchased."

The FAT file system is also used by some open-source software to let Linux and Unix computers exchange data with Windows computers, and by Linux itself to read and write files on Windows hard drives.

Some in the open-source community, like Eben Moglen, who is a Columbia University law professor, the general counsel for the Free Software Foundation and a board member of the Public Patent Foundation (PubPat), are worried that Microsoft could in the future decide to allege that Linux infringes on those patents and seek a royalty.

That could threaten the very core of Linux, which is licensed under the GNU General Public License (GPL) and may not be distributed if it contains patented technology that requires royalty payments.

/zimages/4/28571.gifRead more here about the ins and outs of open-source licenses.

In its decision to re-examine the FAT patent (here in PDF form) the Patent and Trademark Office last week said that "a substantial new issue of patentability, which has not been previously addressed, has been raised …. In particular, storing a checksum of the short filename in the directory entry."

PubPat, a not-for-profit public service organization that describes its mission as "protecting the public from the harms caused by wrongly issued patents and unsound patent policy," in April requested the re-examination of the patent.

In that request the organization said that "unfortunately, Microsoft is using its control over the interchange of digital media to aid its ongoing effort to deter competition from Free and Open Source Software. Specifically, Microsoft does not offer licenses to the patent, [No. 5,579,517], for use in Free Software … and those users are denied the ability to interchange media with machines or devices running Microsoft owned or licensed software," it said.

However, the Patent Office last week revealed that it will not address the issues of "significant public harm" and the allegations that the patent "stands as a potential impediment to the development and use of Free Software" in the current re-examination. The office said these issues are outside its scope.

"If Microsoft successfully commercializes its six FAT patents—we attacked the oldest and narrowest one of them—as it is trying to do with hardware manufacturers like those of flash cards and digital cameras that format such file systems manufacturers, then it could be possible for Microsoft to argue that anybody using a free software system that reads and writes to the MS DOS FAT file system also has to pay a royalty. Everyone has grown accustomed to using those file systems on low-density removable media," Moglen said.

PubPat had challenged the patent validity to ensure that such an attack on the ability of the Linux kernel and other free software kernels to do such a familiar thing would not be brought into question at a later time, Moglen said.

Next Page: Sufficient grounds for re-examination?