IBM will offer up a host of patents--from methods for encrypting data to network-monitoring techniques--free of charge for use by open-source software developers, the company said Tuesday.

Under the plan, IBM says it will immediately contribute 500 patents to what it hopes will become an industrywide "patent commons," from which commercial and private developers can mine commonly used code and programming techniques.

IBM officials say the gesture isn't completely altruistic--they believe the company, along with users, will benefit if more commercial software development is turned over to the open-source community. "The more things they develop, the more we can develop around that," IBM standards VP Bob Sutor says.

IBM will release more patents to open-source developers in the future, Sutor says, adding, "We don't have a fixed timetable."

Coming on the heels of the sale of its PC business to China's Lenovo Group Ltd., the move is a further indication that IBM wants to position itself primarily as a service provider, some analysts believe. "If your goal is to be a provider of higher-value services and solutions, then fighting over who owns a file format is not critical," says John Rymer, VP for application development research at Forrester Research.

The intellectual property represented by the patents will be available only to those programmers working on projects that meet the Open Source Software Initiative definition of open-source software. Among other things, that definition stipulates that open-source software remain royalty-free.

In a thinly veiled shot at Unix-developer SCO Group Inc., IBM says it retains the right to block organizations that file lawsuits asserting patent rights over open-source software from accessing the patents it's contributing to the open source community. In a statement, IBM says the stipulation is necessary to "avoid the possibility that a party will take advantage of this pledge and then assert patents or other intellectual-property rights of its own against open-source software."

SCO has filed lawsuits against IBM and Linux users, including DaimlerChrysler AG and AutoZone Inc., claiming that parts of Linux violate SCO's Unix copyrights.

IBM says it wants to hasten innovation in the software industry by giving up patents that govern routine development techniques and code. At the same time, the company says it will continue to enforce patents covering what it believes are truly innovative advancements. As if to underscore the point, IBM said Tuesday that it earned more than 3,000 patents in 2004--making it the 12th year in a row that IBM has received more patents than any other U.S. company.