Microsoft's Hyper-V, its delayed, VMware-scratching hypervisor-based virtualization software, is now feature-complete and broadly available as a first release candidate.

A beta of the stuff was included in Windows Server 2008 when it launched late last month and Microsoft says the build it put out Wednesday is "updated, near-final code."

The final version, which will be part of the server operating system, is supposed to be out by August in keeping with Microsoft's promise of delivering it 180 days after Windows Server 2008 RTM'd.

To meet that schedule Microsoft had to strip out some features.

With RC1 performance and scalability has apparently been improved and the list of guest operating systems has widened and now includes Windows Server 2003 SP2, SUSE Linux Enterprise Server 10, Vista SP1 and XP SP3. Host server support includes the 64-bit versions of Windows Server 2008 Standard, Enterprise and Datacenter.

So far Microsoft's got English, German and Japanese versions.

In a dig at VMware, Microsoft claims the reason less than 10% of servers are virtualized today is because the schemes available are too complicated and expensive.

And in another dig at VMware, Microsoft suggested that Dell, Fujitsu, Fujitsu Siemens, Hitachi, HP, IBM, NEC and Unisys would be pre-installing the final Hyper-V code on their machines.

IBM, Dell, HP and Fujitsu Siemens pledged a few weeks ago to pre-install VMware's freebie ESX 3i bare metal hypervisor on some of their gear.