Red Hat also criticized Microsoft and Novell's patent cross-licensing deal. Microsoft vowed not to sue non-commercial Linux developers nor Suse Linux users for any possible patent violations, but declined to rule out suing other Linux companies or users.

In its statement, Red Hat also called that threat a looming "innovation tax." It said its Open Source Assurance program would allow customers to continue using Red Hat and JBoss software in case of a legal challenge and indemnify them against intellectual property infringement claims.

Red Hat continued to minimize the fallout from Oracle's move. In an interview yesterday before the Microsoft-Novell announcement, Red Hat's head of support said the company hasn't seen any of its 200,000-plus customers defect to Oracle yet.

"I've asked my support engineers to give me feedback. Honestly, it's been business as usual," said Iain Gray, Red Hat's senior director of global support. Most of Red Hat's customers are signed up for one- or three-year support contracts.

Jeremy Garcia, a Buffalo, N.Y.-based Linux systems administrator who also runs the LinuxQuestions.org Web site, said that Oracle's claim to provide support at half the price of Red Hat is less attractive than it first seems. "No enterprise customers pay anywhere near the published retail price for RHEL," Garcia said. "Having dealt with Red Hat on behalf of many companies, depending on quantity the discounts can be significant."