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First and Ten: Linux 2.6.20 Kernel Goes Virtual

While many Americans were focused on the sports spectacle known as the Super Bowl yesterday, Linus Torvalds was focused on releasing a new Linux kernel.

Version 2.6.20 of the kernel includes a bevy of fixes and features, notably the introduction of KVM (Kernel-based Virtual Machine) virtualization to the mainline kernel .

KVM virtualization in Linux 2.6.20 could potentially challenge open source virtualization specialist Xen, which has been aiming for Linux kernel inclusion for nearly two years. KVM was created and is maintained by technology start-up Qumranet.

However, the leader of the open source Xen project, Ian Pratt, said he doesn't see any competitive issues with KVM in the 2.6.20 kernel.

"Xen is a true hypervisor, whereas KVM is a legacy virtualization solution akin to VMware Workstation, VMserver and Microsoft Virtual PC," Pratt told internetnews.com. "It lacks the benefits of para-virtualization performance enhancements that have been pioneered by Xen and are now being copied by VMware and Microsoft."

Pratt also explained that Xen is no longer actively seeking inclusion in the mainline Linux kernel either.

"The Xen hypervisor is an operating system independent hypervisor that supports many different operating systems (Windows, Solaris, Netware, FreeBSD, OpenBSD, NetBSD) of which Linux is just one (though an important one), Pratt said. "Putting Xen into Linux doesn't make sense: hypervisors are different beasts from operating systems, so they share little code."

Plus, he added, "a large part of the Xen project is all the user space tools and libraries that would be totally out of place in the Linux kernel sources."

Enterprise Linux vendor Red Hat  isn't about to jump on KVM bandwagon for its upcoming Red Hat Enterprise Linux 5 release. Joel Berman, Product Management Director for RHEL told internetnews.com that Red Hat will not backport KVM to RHEL5.

"RHEL 5 will include integrated virtualization based on the Xen technology and Red Hat will be supporting that for at least seven years," Berman said.

Though not part of RHEL 5, KVM will find a home in the released version of Fedora 7 which is expected in April though early adopter can already get KVM in Fedora as a kernel update.

"Fedora moves at a brisk pace and has already offered updates to kernels with KVM," Berman said.

"This is a great example of why Open Source is a superior development model," Berman said. "Xen, KVM, lguest, OpenVZ and UML are very different technologies that are all improving at a rapid rate and have some overlap in capabilities. The open process allows all of these technologies to be examined and melded and eventually become part of the Linux ecosystem. "

The 2.6.20 is the first Linux kernel release of 2007. The prior update, version 2.6.19, was released at the end of November 2006.

In sticking with the football theme Torvalds used with the kernel release announcement, the Linux founder poked fun at Super Bowl Sunday.

"Before downloading the actual new kernel, most avid kernel hackers have been involved in a 2-hour pre-kernel-compilation count-down, with some even spending the preceding week doing typing exercises and reciting PI to a thousand decimal places," Torvalds wrote in the release announcement.

"The half-time entertainment is provided by randomly inserted trivial syntax errors that nerds are expected to fix at home before completing the compile, but most people actually seem to mostly enjoy watching the compile warnings, sponsored by Anheuser-Busch, scroll past."