Microsoft filed suit against car navigation system company TomTom on Wednesday, claiming infringement of eight Microsoft patents related to car navigation systems and file management, several of which appear to be in regard to TomTom's implementation of Linux.

Though this action is specifically aimed at TomTom and is broader than just its implementation of Linux, Microsoft has previously said that free and open source software infringes on at least 235 of Microsoft's patents. Microsoft doesn't mention Linux at all in its main complaint, but does in an associated International Trade Commission complaint (TomTom is a Dutch company).

Microsoft says it has been trying to get TomTom to license its technology for more than a year. Several of TomTom's competitors, including Garmin, license Microsoft technologies or patents for their navigation systems. Microsoft has ramped up its intellectual property licensing business in the last few years in an effort to protect and profit from the $9 billion the company annually spends on research and development.

"In situations such as this, when a reasonable business agreement cannot be reached, we have no choice but to pursue legal action to protect our innovations and our partners who license them," Horacio Gutierrez, Microsoft's VP and deputy general counsel of intellectual property and licensing, said in a statement.

The navigation system patents are related to generating driving directions, in-car computers with "open platforms" or which connect to the Internet, and systems that integrate with and control other vehicle components. The others include two patents for managing file names in a file system and one for managing flash memory.

In the ITC complaint, Microsoft mentions that the TomTom devices in question use Linux to execute an app that generates driving directions from GPS data and that the Linux operating system "provide[s] the devices with file system support for long and short file names, memory management of flash memory, and a platform for integrating and controlling various electrical components used with portable navigation devices."

Microsoft is seeking damages and to halt the sale of 13 TomTom devices it names in its ITC complaint. However, it's not clear whether this case will actually ever make it that far. Gutierrez says Microsoft remains open to licensing its technologies to TomTom.

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