Linspire, maker of the desktop Linux OS once known as Lindows, has signed an intellectual-property agreement that shields its customers from Microsoft's controversial patent claims.

Microsoft has claimed Linux and related open-source software violates 235 of its patents, but the company will not provide information to back its claims. Microsoft will only supply a list of the allegedly infringed patents to companies that have signed agreements with it.

This hasn't stopped Linux companies, such as Novell and Xandros, from signing intellectual property deals with Microsoft that they say will guarantee protection for their customers from future patent claims, and boost future Linux use.

As part of the agreement between Linspire and Microsoft, the companies have agreed to cooperate in several areas. Linspire will work with Novell and Microsoft to develop open-source "translators" that allow Open Office and Microsoft Office users to share documents more easily. The company has also licensed Microsoft's RT audio codec to make its Pidgin IM (instant messaging) client interoperable with Windows Live Messenger and other Microsoft products.

As part of the deal, Linspire also pledged to add support for Windows Media 10 in future releases of its Linux OS distribution. The company also agreed to make Windows Live Search the default search engine in Linspire 5.0.

Linspire changed its name from Lindows in 2004, dropping the name in response to pressure from Microsoft. Microsoft had sued Lindows for trademark infringement, cases it won in Europe, and lost in the US. In the end, in effect, it bought the change with a $20 million investment in the company.

Financial terms of the new agreement between Linspire and Microsoft were not disclosed.