Microsoft FAT Patents Rejected

File allocation table submissions denied over inventorship issues.

The U.S. Patent and Trademark Office has rejected two key Microsoft Corp. patent applications relating to the companys file allocation table file system. But Microsoft officials still hold out hope that the company ultimately will succeed in the quest to patent FAT.

In June of last year, the USPTO said it would re-examine the patent Microsoft holds on FAT, a format used for the interchange of media between computers and digital devices.

That followed the request to re-examine the FAT patent, made in April by the Public Patent Foundation, a nonprofit public service organization.

In September of last year, the patent office initially rejected Microsofts FAT patent application. Last week, the USPTO rejected what are known as the Microsoft 517 and 352 patent applications, involving the long-file-name technology that is central to FAT.

Microsoft officials said the USPTO rejected the applications over an inventorship issue.

"The examiner has requested evidence that all six of the named inventors are properly named as inventors on the patent," company officials said in a written statement. "Microsoft has an opportunity to submit evidence in response to the examiners request and remains optimistic that these issues will be resolved in its favor."

Microsoft officials said their reaction was upbeat because the USPTO did not reject the patent applications on the basis of prior-art claims. In fact, according to David Kaefer, Microsofts director of business development, the USPTO ruled in Microsofts favor on all the FAT prior-art claims, including the prior art submitted by Pubpat.

"Although Im pleased that the PTO has maintained its rejection of the FAT patents, Im disappointed they have withdrawn the prior-art-based portions of the rejections," said Dan Ravicher, executive director of Pubpat, in New York.

"The question over whether these [517 and 352] are quality patents has been settled," said Kaefer in Redmond, Wash. "The public was called in [to submit their Opinions], and these patents stood up."

FAT is used by some open-source software to facilitate the exchange of data between Linux or Unix computers and Windows computers.

Some in the open-source community, such as Eben Moglen, who is a Columbia University law professor, the general counsel for the Free Software Foundation Inc. and a board member of Pubpat, have expressed concern 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 GPL (General Public License) and may not be distributed if it contains patented technology that requires royalty payments.

"If Microsoft successfully commercializes its six FAT patents—we attacked the oldest and narrowest of them—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," Moglen told eWEEK previously.

Mary Jo Foley is the editor of