The Redwood Shores, California-based database and applications giant has not donated any of its own patents to the OIN, which was formed in 2005 to protect Linux from patent threats, but the terms of the license equate to a declaration of patent peace.

Patents owned by Open Invention Network are available royalty-free to any company, institution or individual that agrees not to assert its patents against the Linux System, explained the OIN in a statement.

The non-profit patent group was formed by IBM, Red Hat, Novell, Sony and Philips in late 2005 to stockpile donated patents and license them on a royalty-free basis in return for promises not to assert patent claims against Linux.

Since then it has accumulated more than 100 patents and patent applications, including an initial set of business-to-business e-commerce patents quietly acquired by Novell from the bankrupt Commerce One for $15.5m in December 2004.

According to the terms of the OIN license, the components covered by the agreement include not only the Linux kernel and associated GNU applications, but also other open source projects included in Linux distributions.

That means Oracle has also agreed not to assert patent claims against MySQL AB’s rival open source database, as well as the PostgreSQL database as commercialized by EnterpriseDB, as well as JasperSoft’s business intelligence software, the Gnome and KDE desktops, the Eclipse toolset, and the Apache web server project.

We have been active members of the Linux development community for years, said Oracle chief corporate architect Edward Screven, in a statement. We believe licensing Open Invention Network’s patents provides assurance to anyone working to make Linux better, including Oracle.

Oracle’s approach to patent licensing and open source stands in stark contrast with Microsoft, which entered into a patent covenant agreement with Novell in November through which the two companies promised not to sue each other’s customers.

Microsoft’s chief executive officer, Steve Ballmer, has used the agreement to suggest that Linux contains Microsoft’s intellectual property, however, and the deal has been criticized for driving a wedge between open source providers, not least by the OIN’s chief executive, Jerry Rosenthal.

Through the accumulation of patents that may be used to shield the Linux environment, including users of Linux software, OIN has obviated the need for offers of protection from others, wrote Rosenthal last November.

Oracle’s deal appears to provide the evidence for that, and might also improve the company’s standing in the Linux and open source community following the launch of its Unbreakable Linux attempt to undercut Red Hat.