Hyper-V Server now available as a free download

It isn't like Microsoft to give away an entire operating system for free, but beginning today, it will: A stand-alone server whose sole purpose is to be a hypervisor platform for virtualized guest operating systems, is now available free of charge.

Microsoft Hyper-V Server 2008 is now available in a stand-alone edition that installs on "bare metal," not even requiring Windows Server (existing versions have been Windows Server add-ons). The new version enables server hardware -- especially the kind with built-in virtualization support on its CPU -- to run one or more virtualized operating systems in a virtualized environment.

The company's gamble is that what could conceivably have sold for about $40 can be written off as an investment in the customer, especially if it encourages him to consolidate data centers by installing more than one running instance of Windows on a processor.

Last August, Microsoft announced changes to its Windows licensing scheme, amid the new reality that running server instances can traverse the boundaries of active processors. Today, the company's new Hyper-V page lists the Windows licensing options now that a stand-alone Hyper-V has entered the mix.

Each Standard edition of Windows Server 2008 licenses the use of one physical copy of Windows, plus one virtual machine. The Enterprise edition expands that number to four virtual machines, while the Datacenter edition enables unlimited VMs. These are running instances of Windows that may traverse processor boundaries at any time; the per-processor licensing model has effectively been sacked.

But Hyper-V Stand-alone doesn't include any Windows licenses, so any guest operating system you run under this particular edition must be licensed individually, including Windows.