A couple of weeks ago, IBM announced it was going to offer open access to 500 key open-source software patents for the developer community at large to develop open source programs and work on operating system alternatives to Microsoft Windows (such as Linux).  My favorite French VC blogger (Marc Goldberg) had a good entry on the topic, including a link to a great insight from Business Week:

Why would IBM allow others to use its intellectual property free of charge? In a word: Microsoft. The move is central to IBM's efforts to fend off Microsoft and its Windows monopoly. While the computing giant will continue to innovate and gather new patents as aggressively as ever, at the same time it is stepping up efforts to bolster the world of open-source software. IBM figures that doing so will give it a leg up in selling the software and services that work with the open-source programs it helped develop.

Of course, since Marc wrote his article, Sun Microsystems announced it will open source a component of its Solaris OS.  This is just a precursor to fully opening Solaris 10 completely.  Apparently, Sun is not too worried about IBM or HP taking an application such as DTrace and incorporating it into their own OS versions.  Sun's COO and President (Jonathan Schwartz) challenged IBM in an open letter in his own blog to port its various packages such as DB2, Tivoli and Websphere to run on the Solaris 10 OS (which analysts believe will begin shipping in March). 

Despite all this open source action during the last couple of weeks, open source penetration remains relatively low, with Linux expected to reach 6% of the market by 2007, up from 3% today. By collaborating on the development of operating systems such as Linux and Solaris, players such as IBM and Sun can secure a solid foundation on which to build tech projects and save substantial funds in programming costs as they battle Microsoft for OS supremacy.