The software was in development when Microsoft acquired it -- along with the Virtual PC for Mac and Windows programs -- from Connectix early last year. Microsoft shipped its own updated version of Virtual PC in November.
Microsoft had initially expressed hopes that the software would ship last year, but the launch was pushed back until this year. The company now hopes to deliver the final version of the software -- to be called Virtual Server 2004 -- by the middle of the year. The product will be sold through Microsoft's usual channels, such as computer makers and retailers, as well as directly and through volume licensing. Pricing for the product has not been announced.
Virtual Server is not at all programmed to handle the many tasks for which one might use such virtual-machine software, said Eric Berg, a general manager in Microsoft's Windows Server unit. Rather, Microsoft is looking at Virtual Server as a means to get some customers to consolidate older servers that are running Windows 2000, Windows NT 4 and other older versions of Windows.
Berg said Virtual Server can enable companies to keep running custom programs that are designed for the older operating systems, while the businesses work to switch to a different program or migrate the software to run natively on a newer server OS, for example.
"They want a way to bring those forward to run in Windows Server 2003," Berg said.
Convincing both consumers and businesses to upgrade their operating systems remains one of Microsoft's biggest challenges.
With Virtual Server, the company also has its eye on software testers, who often need to test new programs against a variety of server types. Another likely use, Berg said, is for companies that want the capability to recover after a disaster -- with fewer servers.
Microsoft is tuning the virtualisation software to run various versions of Windows, but it will allow Linux and other x86 operating systems to run as "guests."
"People will be able to run a broad set of x86 operating systems in the Virtual Server guest environment," Berg said, noting that "we'll optimise the experience for Windows."
Microsoft does not plan to offer Linux-specific technical support. "We're not anticipating staffing-up to support questions about another brand of operating system," Berg said.
Microsoft's chief competitor in this area is VMware, which storage giant EMC acquired in January for $625m (£328m) in cash.
Although Virtual Server will compete with products from VMware, particularly among software developers, the two companies are largely headed down different paths.
Microsoft is pitching virtualisation as a way to migrate to Windows Server 2003, while VMware is pitching virtualisation itself as an end point.
VMware sees running multiple operating systems as part of an overall data centre that can reallocate servers, storage and other resources on the fly -- a vision that EMC is heavily promoting.
Michael Mullany, vice president of marketing for VMware, said the customer's choice will often come down to how the company wants to use the virtual-machine software. "Is virtualisation a core IT strategy? Or do they just want something to run multiple operating systems on a single system?" said Mullany.
On the competitive front, Mullany noted that VMware already has been on the market with server products for three years and has 5,000 customers. Also, the company provides an equal level of support for Linux, Novell NetWare and Windows, he said.
"Most customers want something that works equally well with Linux [and] Windows," Mullany said, adding that VMware's first product was for Linux.
For its part, Microsoft touts as advantages of Virtual Server its tight integration with Windows Server 2003, built-in automation tools and support for OS/2.
Development of Virtual Server was well under way when Microsoft acquired the assets of Connectix. Rather than release the product earlier, though, Microsoft made the technology available as a "customer preview" version and has been working to add features and improve security, Berg said. The company said the preview has been downloaded about 42,000 times.
The beta programme provides newsgroup-level support to about 15,000 registered users and other testers, with a more comprehensive joint-development program under way, with about 30 early development partners.
