Microsoft snatches FAT patents win after all

Two patents covering one of Microsoft's main Windows file-storage systems are valid after all, federal patent examiners have decided.

The decision, announced on Tuesday by the software giant, effectively ends a two-year saga over the patents and reverses two non-final rulings - the latest issued in October - in which the US Patent and Trademark Office rejected Microsoft's claims.

In their latest action, filed last week, the examiners concluded the company's File Allocation Table (FAT) file system is, in fact, "novel and non-obvious", entitling it to patentability. Now the office is in the process of issuing a "patent re-examination certificate", which signals the finality of the decision, a Microsoft representative said.

The Patent Office agreed to re-examine two patents covering the FAT system, a common means of storing files which is also used by some Linux- and Unix-related products to exchange data with Windows, at the request of a little-known public interest group called the Public Patent Foundation in April 2004.

That organisation claimed there was "prior art" that proved Microsoft was not the first company to come up with the file format.

It also voiced concern Microsoft would try to seek royalties from companies that sell and support Linux for using the technology, potentially posing a threat to the free software community. Under the terms of the Free Software Foundation's General Public License, Linux cannot be distributed if it contains patented technology that requires royalty payments.

Microsoft indicated in the past it would license the file format. In December 2003, it said it had struck such a deal with flash-memory vendor Lexar Media.

The Patent Office's final decision followed several non-binding decisions that were unfavourable to Microsoft. After issuing its preliminary rejection of the patents in September 2004, examiners handed down a similar decision about a year later.

David Kaefer, Microsoft's company's director of business development, said on Tuesday the company was "very pleased" with the office's final decision. Kaefer added: "This result underscores the validity of these patents but also the importance of allowing third parties to request re-examinations."

CNET News.com's Ina Fried contributed to this report

Anne Broache writes for CNET News.com