Last week, Microsoft sued TomTom for infringing on patents relating to (among other things) the format of its File Allocation Table 32-bit (FAT32) disk format. These patents relate to mundane issues like how to translate pretty names like "C:\Temporary Files" into ugly short ones like "C:\TEMPOR~1" that older programs can understand, and the layout of files on the physical media such as hard drives or flash memory.So what are the implications of Microsoft having a patent on FAT technology? Let's look at a simple example. Whenever you plug a flash drive into your PC, the odds are that it's formatted with Microsoft's FAT32 technology. If you take that flash drive to another non-PC device, the software on that device needs to be able to understand the FAT32 format in order to read the files. Microsoft says that to do that, you need to license its patents.

OK, there is one other option. Instead of using a standard file system such as FAT32, devices could use their own proprietary formats on a flash drive. Ha ha, they've avoided licensing the patents; take that, Microsoft. Oh, there is just one little complication: Since Windows doesn't understand how to read the format, users will need to install special drivers or applications to read it. That is so incredibly cumbersome as to be unworkable, so the only reasonable choice is to use FAT32.

If the operating system market was shared among half a dozen smaller players, you can bet that there would be an open, royalty-free standard file system format for interchanging files among them. Microsoft's near-monopoly on PC operating systems means that non-PC devices must use FAT32 not because it's best, but because it's ubiquitous. Allowing Microsoft to control the FAT32 patent this way is allowing it to leverage its monopoly status.