Xen lures big-name endorsements

(continued from previous page)

standard computer feature. "Being ubiquitous on Linux is the first step to that," he said.

Xen and other approaches to dividing a computer into separate partitions rely on a concept called virtualization, which lets programs run on a software simulation of actual hardware. In the case of VMware, this foundation is called a virtual machine.

One difference between VMware and Xen: The former completely simulates a machine, which theoretically allows any operating system to run unmodified on a virtual machine. Xen, on the other hand, uses "paravirtualization," which doesn't go as far. That means faster performance but also requires an operating system to be modified to run, Pratt said.

Higher-level software, however, doesn't need to be modified, he said.

The requirement for a modified operating system will loosen with Intel's coming Vanderpool Technology, or VT, due in 2005, Pratt said. It will mean unmodified operating systems will run on Xen, though not as fast as modified ones. That means Windows will run on Xen even though open-source programmers don't have access to change Windows itself.

Falling by the wayside
Xen competitors that haven't caught on include Plex86 and User-mode Linux. While the latter made it into the most recent version of SuSE Linux from Novell, it likely won't last.

"User-mode Linux is most likely dead," Schlaeger said. The management tools Novell developed to administer that software will be re-used to control Xen instead, added Markus Rex, general manager of SuSE Linux.

Xen will likely be incorporated into Novell's upcoming SuSE Linux Professional 9.3 and later into the next version of its premium product SuSE Linux Enterprise Server, Rex said.

Linux seller Red Hat also has Xen plans. The virtualization package is being added to Red Hat's experimental Fedora Core 4 product and will probably be in version 5 of Red Hat Enterprise Linux, said Paul Cormier, executive vice president of engineering. Like Novell, Red Hat plans to add management tools to control aspects such as the creation or removal of Xen virtual machines.

Hewlett-Packard strongly endorsed Xen this week, saying it will contribute software to the effort. "Our expectation is that Xen will provide a viable, open-source alternative in virtualization platforms," said Martin Fink, vice president of Linux, in a keynote address at the Linux show. HP, too, hopes to profit from software to manage virtual machines.

Intel began contributing software to the Xen project in January so it could use VT extensions, said Phil Brace, director of marketing for Intel's digital enterprise group.

Expanding into new areas
Currently Xen works with Linux on computers using x86 processors such as Intel's Pentium, but efforts are under way to extend it into other domains. This week, AMD announced it's helping to bring Xen to 64-bit x86 chips such as its Opteron, future generations of which, employing "Pacifica" technology, will have new virtualization support.

There's experimental support for Intel's Itanium family now in Xen, Pratt