The accusation follows Oracle's decision in March to stop developing new versions of its software for Intel's high-end Itanium processor. HP's Integrity servers run on the Itanium chips, and to HP in order to undermine the sale of its products.

"Oracle's sudden departure from its commitment of long-term support for the Itanium platform is a calculated effort to thwart competition from HP and harm its customers," HP , filed in the Superior Court in Santa Clara, California.

HP had already complained that Oracle is harming the companies' joint customers in violation of its agreements with HP. Its lawsuit Wednesday describes in more detail what it sees as Oracle's "coercive" tactics.

When Oracle announced its plan to end support for Itanium, it said it would continue to support customers running existing versions of its software on the Intel chip. Instead, according to HP, Oracle has refused to provide those customers with critical bug fixes for its software.

"Oracle has told customers that no fix is available and that to resolve the problem they will have to move to the next version of Oracle's software," the lawsuit said. "Because Oracle has announced that the next version of its software will not run on Itanium servers, this course of action by Oracle effectively forces customers to abandon their choice of Itanium servers in favor of server hardware they do not prefer."