Microsoft on Monday said it would remove the price tag from its Virtual Server and begin offering the virtualization technology as a free download to Windows users.Virtual Server 2005 R2 Enterprise Edition has carried a price of $199 since it shipped in December 2005. The news came on the opening day of the LinuxWorld Conference and Expo in Boston, where Microsoft also said Virtual Server add-ins to support Linux are now available and that Microsoft would provide support under current Microsoft support contracts for Linux guest operating systems running on Virtual Server 2005 R2. In addition, Microsoft said the first service pack for Virtual Server 2005 R2, which features integration with virtualization technologies from Intel and AMD, would be delayed until early 2007.Microsoft also said the standard version of Virtual Server is being discontinued.For the 5,000 customers that have already purchased Virtual Sever, Microsoft said those with Software Assurance maintenance contracts would be \u201ctaken care of,\u201d but stopped short of saying Microsoft would offer refunds to those that had licensed the server.\u201cIt could mean different things for different SA customers,\u201d says Jim Ni, a group product manager for the Windows Server team at Microsoft. \u201cWe want to craft something that is a win-win situation.\u201dNi said users without contracts have likely already realized the value of their investment through consolidation and other cost savings supported by virtualization.Ni said Microsoft believes virtualization should be delivered as part of the operating system and that offering Virtual Server 2005 R2 for free provides a perfect way to get users started and on a path to Longhorn Server, due to ship in 2007, which will feature an advanced virtualization technology called hypervisor.But experts say Microsoft\u2019s hand was forced by market leader VMWare, which said in February it would offer VMWare Server for free this summer, and by Red Hat and Novell, which both plan to make open source Xen virtualization technology a part of their respective Linux operating systems.\u201c I don\u2019t think Microsoft had much choice in the matter,\u201d says Gordon Haff, an analyst with Illuminata. \u201cThe bottom line is there is not a whole lot of market to buy that product from Microsoft.\u201dMicrosoft is taking the same angle as VMWare by offering introductory capabilities and then trying to move users to more robust features, such as hypervisor and management tools, to support more important business processes.On Monday, VMWare said that its virtual machine disk format specification for defining and formatting virtual machines would be offered free of charge. Patch, provisioning, security, management, backup and other infrastructure solutions for virtual machine environments all depend on this format.Microsoft has its own format called Virtual Hard Disk, which it began offering royalty-free in May last year, and Microsoft on Monday announced it now has 45 vendors signed onto the program. The newest licensees include Brocade, Diskeeper, Fujitsu-Siemens, Network Appliance, Softricity, Virtual Iron and XenSource.Microsoft said the nine new Linux add-ins, which are installed on the Linux guest operating system, are designed to improve the mouse and display driver, SCSI disk emulation, and the guest and host time synchronization, heartbeat and coordinated shutdown.Microsoft\u2019s Linux add-ins support Red Hat Enterprise Linux 2.1 (update 6), Enterprise Linux 3 (update 6), and Enterprise Linux 4, as well as, standard distributions of Red Hat Linux 7.3 and 9.0. Also supported are Novell\u2019s SuSE Linux Enterprise Server 9 and standard distributions of SuSE Linux 9.2, 9.3 and 10.Virtual Server 2005 R2 runs on Windows 2003 and later (Microsoft recommends the Windows 2003 R2 version). Last year, Microsoft introduced a new virtualization-licensing plan where users can run four virtual machines (VM) on top of the Enterprise Edition of Windows Server 2003 R2 without any additional licensing costs beyond the base server.