NTFS-3G is a free NTFS driver for Linux, FreeBSD, OpenSolaris and a few other operating systems, also a part of most Linux distros. Project lead and developer Szabolcs Szakacsits founded Tuxera in 2008 with the expressed goal to provide exFAT and NTFS drivers in plug-and-play interoperability with Windows.

This goal now seems to have been met with the newly signed contract with Microsoft in which Tuxera developers have access to the technical data and test tools of Microsoft's exFAT drivers. Tuxera will provide Linux drivers to OEMs that use exFAT for flash memory in numerous electronic devices. Microsoft introduced the Extended File Allocation Table filesystem, also known as FAT64, with Windows CE 6.0 in 2006. The filesystem allows file sizes beyond 4 GBytes, the upper limit for FAT32. The SD Association, an alliance of more than 1,100 companies using SD technology, had selected the Microsoft filesystem standard for its SDXC memory cards.

The Intellectual Property Agreement essentially adds Tuxera to Microsoft's dealer network according to Tuxera's assessment as the "first independent software vendor" in the exFAT program. It took a year's work, says Tuxera CEO Mikko Välimäki in his blog: "We came to Redmond to have an agreement, and in the end that is what we got. Three days of meetings and talking." Even Microsoft was impressed by the eagerness with which an open source firm wanted to close a deal with them: "After we had signed, someone from Microsoft asked: 'Have we ever done a deal so quickly?' 'I don't think so,' was the answer."

Other open source ventures are somewhat less relaxed in their dealings with Microsoft over FAT patents. The TomTom navigation software maker has had its patent legality issues with Microsoft, the Open Invention Network (OIN) is gathering prior art evidence against the Redmond giant, and Linux developers are busily removing FAT code from their products.

Meanwhile Tuxera managers are celebrating the deal. CTO Szakacsits puts it this way: "Adding exFAT into our existing NTFS product portfolio is the logical step to help our customers solve any interoperable file system need they have." The financial part of the deal has not been revealed.