Release to manufacturing is the formal, pre-retail release of a Microsoft product that is sent to server and PC manufacturers who can then add it to their own hardware for sale without the restrictions of beta tests.

The early release is at least partly due to what both Microsoft executives and beta testers called an unusually smooth final test and development process, according to Jeff Woolsey, senior program manager, virtualization for Microsoft.

"The testing program was smooth enough and went quickly enough that we were able to add [support for] a whole series of guest operating systems that weren't on the list for the initial release," Woolesly says. Most of those are various editions of Windows Server, but several versions of Linux are also represented.

Woolsey's version of the development process can be expected to be rosy, but doesn't miss the mark by much,, according to Chris Steffen, principal technical architect at Kroll Factual Data, a credit-reporting and financial-information services agency.

"I've attended some conferences where I hear people say Hyper-V isn't ready for prime time, that it's a 1.0 product and it's not reliable and all that, and I haven't the foggiest clue what they're talking about," says Steffen, who's been testing Hyper-V for months and is migrating Kroll Factual Data's servers to it as quickly as his staff can migrate them.

Kroll Factual Data, a subsidiary of security specialist Kroll, Inc., runs about 300,000 transactions per day across about 300 physical servers and 1,600 virtual servers running on Microsoft's Virtual Server product, the predecessor to Hyper-V.

"We run probably 300,000 transaction per day over our environment, with a little less than 300 (physical) hosts and about 1600 on Virtual Server," Steffen says. "About 100 of those are running Hyper-V and they're completely solid. It's hard to say how much of an improvement [Hyper-V is compared to Virtual Server], but at this point we're seeing something like a 15 to 20 percent lift."

That estimate is low compared to what many of the customers of Oakland-based integrator and virtualization services company Convergent Computing is seeing, according to Rand Morimoto, the company's president.

"Even before it ships, the product has proven to be reliable," Morimoto says. "You would think this would have the potential for problems. It's a 1.0 product, it's an infrastructure product. But the thing is, it's still based on Windows, and on [Microsoft's] virtualization stuff, which they've been doing for years. We were surprised when the product first came out," Morimoto says. "We expected slow performance, instability. We expected the worst, but we didn't see it. "