Microsoft Virtual Server
Original author	Connectix
Developer	Microsoft
Initial release	September 13, 2004; 21 years ago (2004-09-13)
Final release	Virtual Server 2005 R2 SP1 / June 11, 2007; 18 years ago (2007-06-11)[1]
Operating system	Windows XP,Windows Server 2003,Windows Vista[1]
Successor	Hyper-V
Type	Hypervisor
License	Freeware
Website	www.microsoft.com/virtualserver/

Microsoft Virtual Server was a virtualization solution that facilitated the creation ofvirtual machines on theWindows XP,Windows Vista andWindows Server 2003operating systems. Originally developed byConnectix, it was acquired byMicrosoft prior to release.Virtual PC is Microsoft's related desktop virtualization software package.

Virtual machines are created and managed through a Web-based interface that relies onInternet Information Services (IIS) or through a Windows client application tool called VMRCplus.

The last version using this name was Microsoft Virtual Server 2005 R2 SP1. New features in R2 SP1 includeLinux guest operating system support, Virtual Disk Precompactor,SMP (but not for the guest OS),x64 host operating system support, the ability to mount virtual hard drives on the host machine and additional operating systems support, includingWindows Vista. It also provides a Volume Shadow Copy writer that enables live backups of the Guest OS on aWindows Server 2003 orWindows Server 2008 host. A utility to mountVHD images has also been included since SP1. Virtual Machine Additions for Linux are available as a free download. Officially supported Linux guest operating systems includeRed Hat Enterprise Linux versions 2.1-5.0,Red Hat Linux 9.0,SUSE Linux andSUSE Linux Enterprise Server versions 9 and 10.^[2]

Virtual Server has been discontinued and replaced byHyper-V.

• VPC has multimedia support and Virtual Server does not (e.g. no sound driver support).
• VPC uses a single thread whereas Virtual Server is multi-threaded.
• VPC will install on Windows 7, but Virtual Server is restricted from install on NT 6.1 or higher operating systems i.e. Server 2008 R2 and Windows 7.
• VPC is limited to 127GB .vhd (per IDE CHS specification), however Virtual Server can be made to access .vhd up to 2048GB (NTFS max file size).^[3]

Microsoft acquired an unreleased Virtual Server from Connectix in February 2003.The initial release of Microsoft's Virtual Server, general availability, was announced on September 13, 2004.^[4] Virtual Server 2005 was available in two editions: Standard and Enterprise. The Standard edition was limited to a maximum 4 processors for the host operating system while the Enterprise edition was not.

On 2006-04-03, Microsoft made Virtual Server 2005 R2 Enterprise Edition a free download,^[5] in order to better compete with the free virtualization offerings fromVMware andXen, and discontinued the Standard Edition.^[6] Microsoft Virtual Server R2 SP1 added support for both Intel VT (IVT) and AMD Virtualization (AMD-V).^[7]

Known limitations of Virtual Server, as of September 2007^[update], include the following:

• Will not install on Windows 7 and Server 2008 R2 or newer operating systems. Upgrades from Vista/Server2008 can be patched.
• Although Virtual Server 2005 R2 can run on hosts withx86-64 processors, it cannot run x64 guests that require x86-64 processors (guests cannot be 64-bit).^[5]
• It also makes use ofSMP, but does not virtualize it (it does not allow guests to use more than 1 CPU each).^[5]
• Performance may suffer due to the way the instruction set is virtualized in this platform, with very limited direct interaction with the host hardware.^[8][9]

• Virtual appliance
• Virtual disk image
• x86 virtualization

• Benchmarking Microsoft Virtual Server 2005Archived 2006-04-28 at theWayback Machine
• Benchmarking VMware ESX Server 2.5 vs Microsoft Virtual Server 2005 Enterprise EditionArchived 2006-05-03 at theWayback Machine
• HyperAdmin: Microsoft Virtual Server Management
• Microsoft Server Virtualization for government agencies
• Microsoft Virtual Server 2005 R2 Resource Kit Book
• Microsoft Virtual Server 2005 R2 SP1
• System Center Virtual Machine Manager
• System requirements for Microsoft Virtual Server 2005

• Virtualization software
• Microsoft server technology

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• Articles containing potentially dated statements from 2007
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