Microsoft Integrating Hyper-V Into Windows 8 Clientby Andrew Cunningham on September 7, 2011 4:30 PM EST
Microsoft is beefing up virtualization support in Windows 8 with Hyper-V, writes Microsoft's Mathew John on the Building Windows 8 blog. Hyper-V was previously available in Windows Server 2008 and Windows Server 2008 R2, but in Windows 8 its functionality is also being rolled into the client version of the operating system.
Hyper-V allows users to run multiple operating systems on the same computer at the same time - if its functionality sounds familiar, it's because programs like VirtualBox, VMWare Workstation, and Parallels (for the Mac users among us) have all been providing similar functionality for years. This isn't Microsoft's first foray into this space, either - among other things, Microsoft's Windows Virtual PC (which enables XP Mode on Windows 7 machines) is also virtualization software.
One of Hyper-V's most appealing features compared to basic consumer-level virtualization software is dynamic memory allocation - a Hyper-V-enabled VM with 2GB of RAM allocated to it will only use the RAM it needs, leaving the unused portion of that 2GB available to the host OS or to other VMs. Microsoft notes that up to four VMs can be hosted on a 64-bit system with 4GB of RAM, though more VMs will require a greater amount of memory.
Use of Hyper-V will require a 64-bit version of Windows 8, 4GB or more of RAM, and a CPU supporting either Intel's VT-x or AMD's AMD-V virtualization technology, and Second Level Address Translation (SLAT). Hosted operating systems can be either 32 or 64-bit, and can make use of up to 32 processors and 512GB of RAM. For complete details on Hyper-V and specifics on its implementation in Windows 8, read the full post on the Building Windows 8 Blog.
Source: Building Windows 8 Blog