Why is Microsoft suing TomTom? Why doesn't TomTom just pay up? Interoperability is of course part of what makes Microsoft a popular choice among the technologically illiterate. Many companies deliberately adopt open standards to encourage other products to work more easily with theirs; Microsoft deliberately chooses just the opposite. Will your Windows XP machine recognize any open source file systems? You can mount NFS with their "Services for Unix" but I'd guess that's far beyond a typical Windows user's skill set. No, TomTom and everybody else needs FAT, and Microsoft is going to make them pay for the privilege.