Adverse decision in re-exam of Microsoft FAT patent

This week, the USPTO rejected what are known as the Microsoft '517 and '352 patent applications, involving the long-file-name technology that is inherent to FAT.

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, Microsoft's director of business development, the USPTO ruled in Microsoft's favor on all of the FAT prior art claims, including the prior art submitted by Pubpat.