Microsoft sued TomTom in 2009 for patent infringement[1]. One aspect of the suit...

Microsoft sued TomTom in 2009 for patent infringement[1]. One aspect of the suit concerned infringement in the implementation of the FAT filesystem in TomTom's Linux-based GPS navigation devices.

The two parties eventually settled[2].

[1] http://arstechnica.com/microsoft/news/2009/02/microsoft-sues...

[2] http://arstechnica.com/microsoft/news/2009/03/microsoft-and-...