UPDATED: Microsoft denied patent for FAT filing system

By Steve Malone

Posted on 30 Sep 2004 at 14:29

Microsoft has lost the first round in the battle to patent the FAT filing system used in DOS and which formed the basis of the disk management system of early versions of Windows.

The US Patent and Trademark Office decided in a review of the patent granted to Microsoft in 1996 that it did not differ sufficiently from the work of other programmers to merit legal protection.

The challenge to the 1996 patent was mounted in April of this year by the Public Patent Foundation (Pubpat) after Microsoft began to start collecting royalties on the patent. Whilst these were considered token, it was feared that the patent could be used to restrict the development of open source projects which rely on FAT technology.

As part of the adjudication process, Pubpat introduced as evidence several items of 'prior art' which predated the Microsoft patent. The Patent Office decided, that based on the evidence of previous work, the basis of the Microsoft patent 'would have been obvious at the time....to a person having ordinary skill in the art'.

'The Patent Office has simply confirmed what we already knew for some time now, Microsoft's FAT patent is bogus,' claimed Dan Ravicher, Pubpat's Executive Director. 'I hope those companies that chose to take a licence from Microsoft for the patent negotiated refund clauses so that they can get their money back.'

However, Microsoft doesn't see this as the end of the matter. The company told us `This latest action by the PTO is just one step in a long process. The PTO has not revoked the patent, it has simply put the claims in question and requested Microsoft to provide arguments supporting our initial claims or amending our claims. We are looking forward to having our first opportunity to weigh in with Microsoft's side of the story.`