VMware moves to deflect Xen, Microsoft

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paravirtualization process. VMware said its flagship software, ESX Server, will permit the use of operating systems that support paravirtualization. "We view paravirtualization as another operating system interface. We will support it just as any other operating system interface," the company said.

XenSource's Crosby said standardizing management interfaces through a standards group such as the Distributed Management Task Force, as Raghuram said VMware might, would be "terrific." On the other hand, XenSource CEO Moshe Bar said Xen's paravirtualization communication protocol is much more efficient than VMware's.

As for the storage method, Xen simply uses standard Linux compression software, and Microsoft in April said it would license its own disk format, called Virtual Hard Disk, for free.

Besides the open interfaces, VMware hopes it will boost its fortunes through sharing its software's underlying source code with its business partners. The sharing program is called the Community Source program.

Some partners are expected to add "black box" software modules into their own versions of VMware, letting them differentiate their products from others', Greene said. Others are expected to add features that will be shipped with VMware's general products. "Overall, we think it's going to allow a lot more innovation," Greene said.

The sharing stops several steps short of that employed by the open-source movement, which creates Linux, Xen and countless other products through a collaborative process that also lets customers download and use the software for free.

But VMware's approach balances that openness with confidentiality, Greene said. And there are significant allies in the code-sharing plan, including Cisco Systems, BEA Systems, IBM and HP, she said.

Catching up to VMware
VMware has made a tidy business out of virtual machines. In EMC's most recent quarter, the subsidiary garnered $91 million in revenue, a 70 percent increase over the year-earlier quarter.

Microsoft has major market power, though, and believes virtualization is best handled as an operating system feature, not a standalone product. "Virtualization is something that belongs in the operating system," Ni said. "As customers look at virtualization services, they'll ask, is it part of the OS? And who's the OS vendor out there I really trust? And wouldn't I get it from them?"

But Microsoft has some work to do. Virtual Server is in the market now, but the company is pinning much of its hopes on a successor that takes the same paravirtualization approach as Xen. Virtual Server today runs on top of a copy of Windows, but the forthcoming Windows Hypervisor will, like Xen, run below it and directly atop the hardware.

The Windows Hypervisor will debut with a version of Windows currently code-named Longhorn Server, due in 2007. However, Ni said, it might well debut with an update or service pack to Longhorn Server, not the initial version of the operating system.

If Microsoft misses the initial Longhorn Server launch, it could have a long wait to introduce a major new feature such as a hypervisor. The company said on its Web site that it plans to issue "a release update approximately two years after each major release."

Xen, too, has some catching up to do. Although the project has been anointed by major Linux sellers, the software still is relatively immature. Programmers have been making progress with new features, though, including the addition of multiprocessor support.

[Scott W]

virtual server?

i can understand people running VMWare and Xen to simulate a windows environment for testing software and other stuff, with the security and stability of UNIX and linux, but why would anyone run MS' offering with its widely renowned reputation for insecurity and instability? why would they need to simulate a unix/linux environment since most likely they won't be coding for that? ok maybe they want to run another instance of windows, but only the maschistists will want to subject themselves to THAT much punishment. running the risk that window, virtual server AND the windows on top of it and hoping that it will run reliably is like building a house of cards in a hurricane.