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FAT patent fight not over yet


On Tuesday, the U.S. Patent and Trademark Office (USPTO) reaffirmed a pair of patents held by Microsoft covering the File Allocation Table, but sources close to the Public Patent Foundation indicate that this will not be the end of the story of efforts to overthrow these patents.

Sources said, “the re-issuance of the patent is based on the examiner’s having accepted an argument previously advanced by Microsoft and previously rejected in the history of the patent, so documented on the file wrapper (the docket sheet of activity which accompanies each patent).” Therefore, the PUBPAT (the Public Patent Foundation) is “not precluded from bringing a new reexamination request, and there is every reason to believe that (it) will be doing so.”

Officially, Dan Ravicher, PUBPAT’s executive director and founder, said that, “If Microsoft sues anyone for infringing them, the defendant in any such suit can raise any defense they’d like, including invalidity, and even including invalidity in light of this same prior art.”

Indeed, “The patent office’s decision has no preclusive effect on a court and there are indeed cases where the patent office made a decision in a reexamination supporting a patent and a court later looked at the same exact issue, disagreed with the PTO, and found the patent invalid,” said Ravicher.

In fact, Microsoft doesn’t even have to sue anyone for the patents to be taken up in court.

“A party who is under a reasonable apprehension of suit for infringement can file a declaratory judgment action in US District Court asking the court to determine that the patents are not infringed or that they are invalid,” said Craig Bachman, a partner in the Pacific Northwest law firm of Lane Powell.

A Linux vendor might, or might not, qualify to sue Microsoft, since while there has been much talk that Microsoft could use the patents against them, there has been no actual legal action against open-source use of the patents at this time, according to Bachman.

Ravicher believes that Linux users don’t need to be overly worried about the patents yet.

Things are “no different than before the reexamination; these patents exist and must be appropriately respected, but not overly feared. All that has happened is that Microsoft has won a debate where they were the only party allowed to speak, in that the patent reexamination process bars the public from rebutting arguments made by Microsoft,” said Ravicher.

“We still believe these patents are invalid, and that a process that gave the public equal time to present its positions would result in them being found as such.”

Others are more concerned.

Florian Mueller, founder of, which fights against patent law in the European Union, said, “This is now a situation in which Microsoft could cause major problems to Linux vendors and users. Microsoft may not want to do that yet for other considerations, but the USPTO’s decision gives Microsoft the strategic option to do so at a time of its choosing,” said Mueller.

Mueller added, “The example of the FAT patents shows that all those patent quality initiatives and patent pledges have no significant value to open-source developers, vendors, and users, if Microsoft ever wants to go for Linux’s throat.”

With this decision to uphold the patents, the USPTO reversed its October 2005 decisions against the patents. PUBPAT had strived for over two years to strike down the FAT patents (5,579,517 and 5,758,352), on the grounds that they contained “prior art.”

Specifically, these file system patents impact programs like Samba, which make it possible for Linux systems to have read and write access to Windows FAT-based file systems, and vice-versa. Many such programs are licensed under the GPL (General Public License). In turn, the GPL forbids the distribution of programs that use patented technologies necessitating payment of any royalties. Microsoft insists that it be paid a royalty for the use of these patents.

This means, “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, said Eben Moglen, a Columbia University law professor and the general counsel for the Free Software Foundation in an earlier interview on the FAT patents.

If the patents are upheld, this would make it difficult, if not impossible, for GPLed software to access FAT file systems.

A version of this story first appeared in Linux-Watch.

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