Microsoft has claimed in the past that technology used in the main body of the Linux open source operating system, the 'kernel', infringes patents which it owns. It has not so far tested those claims in court.
It has now taken action against TomTom over eight patents which it owns, and a Microsoft lawyer said that three of those claims are related to TomTom's use of Linux.
"[The] TomTom implementation of the Linux kernel…infringes these claims," Microsoft's deputy general counsel for intellectual property Horacio Gutierrez told CNET News. "There are many flavors of Linux [and] many implementations of the Linux kernel. Cases such as these are very fact-specific."
Microsoft said in 2007 that Linux infringed 235 of its patents. General counsel Brad Smith said that 42 of those were violated by the kernel alone, while 65 were infringed by the graphical interface of Linux.
It is believed, though, that if the TomTom case goes to trial it will be the first test of Microsoft's claims in a court.
"We have taken this action after attempting for more than a year to engage in licensing discussions with TomTom," said Gutierrez in a statement. “We have an established intellectual property licensing program, and the patents involved in this case, relating to innovations in car navigation technology and other computing functionality, have been licensed by many others."
"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. Other companies that utilize Microsoft patents have licensed and we are asking TomTom to do the same," he said.
Microsoft would rather resolve the issue by TomTom's taking out of a licensing agreement than through litigation, it said.
Five of the patents which Microsoft claims are infringed are specific to in-car navigation systems. The other three relate to general computer operations.
Two separate patents are titled 'Common Name Space for Long and Short Filenames', while the third is 'A Method and System for File System Management Using a Flash-Erasable, Programmable, Read-only Memory'.
Gutierrez told Fortune magazine in 2007 that he did not believe that the alleged patent infringement in Linux was coincidence.
"This is not a case of some accidental, unknowing infringement," he said. "There is an overwhelming number of patents being infringed."
As well as a suit in Washington State, Microsoft has filed an application with the International Trade Commission to block imports of the devices by the Dutch-headquartered company.
Microsoft received its 10,000th patent earlier this month.
