Sun Microsystems is aiming to undercut Red Hat with a support package that makes open source Solaris half as expensive to run as Red Hat's Linux.

Sun has joined Oracle and Microsoft in putting price pressure on the largest Linux distributor, Red Hat, by launching Open source Solaris 10 11/06, with support costs around half the price of a comparable support plan from Red Hat.

"It's obvious that Sun is gunning for Red Hat," said Jonathan Eunice, founder of the technology research firm Illuminata. Solaris is a Unix-based operating system; like Linux, it is available for free, though Sun charges for support. Support costs have become a competitive issue since October 2006, when Oracle announced Linux support at a lower price than Red Hat. In November, Mmicrosoft aligned with Linux distributor Novell.

Sun's Solaris annual support contracts range from US$240 to $1,180 for one- or two-socket x86 servers, depending on whether the buyer chooses the "basic" or "premium" plan. Sun's basic plan costs about 40 percent less and the premium plan about 50 percent less than comparable Red Hat plans, said Sun spokesman Bob Wientzen.

Red Hat's Web site lists Red Hat Linux ES basic for $349 per year, per system, and Red Hat Linux AS premium for $2,499. A Red Hat spokesman did not return calls and an e-mail requesting comment, but after Oracle's move last fall, Red Hat chief executive officer Matthew Szulik said Red Hat would not lower its prices due to a competitor's price cuts.

Pricing its support below Red Hat's is "a volume play," said Eunice, so that Solaris can gain market share against competing operating systems.

The new Solaris is available as a free download from Sun's Web site and can run on Sun x86 servers, but also on servers made by Dell, Hewlett-Packard and IBM.

The most notable improvement in the operating system, Eunice said, is the Solaris Clusters feature for business continuity and disaster recovery. Clustering makes it possible for servers to work together so that if one server fails, the workload can be quickly moved to another server. The previous version of Solaris Clusters didn't work as well on x86 processor platforms as on Sun's own Sparc platform, but the upgrade fixes that shortcoming.

"Sun has made enormous strides. This is a rockin' product now," Eunice said.

Meanwhile, Sun's Wientzen declined to confirm media reports that Sun is going to license open source Solaris under the GNU General Public License (GPL) as it did with its Java programming language. "We are not ruling it out, but we have no announcement about that today." he said.

On the virtualisation front, Solaris 10 11/06 now supports the Xen hypervisor, an open-source software interface for virtual machines. Sun's Logical Domains and Solaris Containers features make it possible for a server to run as many as 32 different operating systems on a Sun server powered by Sun Sparc 11 processors.