Microsoft Wednesday made Windows Server 2003 R2 generally available to users and partners and will make it available in the near future to volume licensing customers with Software Assurance maintenance contracts.Microsoft on Wednesday made generally available Windows Server 2003 R2 to users and partners and will begin shipping it to volume licensing customers with Software Assurance maintenance contracts this week.In addition, Microsoft released Service Pack (SP) 2 for Internet Security and Acceleration (ISA) Server 2004 and updates to its Simple SAN storage initiative, both of which work in conjunction with R2. Microsoft also is using R2 as the launching pad for new licensing for virtualization software, which took effect Dec. 1, 2005.Windows Server 2003 R2, which ships in x64 and x86 versions, is built on Windows Server 2003 SP1 and is the first R2 release of the server operating system\u00a0since Microsoft initiated a release cycle in May 2004 that called for a major operating system upgrade every four years with a lesser \u201cR2\u201d release in between. The last major operating system upgrade was in 2003.\u201cWith the interim release we do not change the underlying kernel like a major release,\u201d says Jeff Price, senior director in the Windows server group at Microsoft. \u201cIt is really adding targeted functionality. People can roll this out without fear of application incompatibility or service pack issues.\u201dThose types of issues in the past are just one reason corporate users have been cautious in adopting new versions of the Windows server platform.The R2 release is a free upgrade for users with Software Assurance maintenance contracts. Those without contracts must pay for a new license.In December, Microsoft shipped the final beta of R2. The first public beta was in March.Key to the server operating system\u00a0is an identity technology called Active Directory Federation Services (ADFS). ADFS is one of the final pieces of Microsoft\u2019s identity management platform and it also represents the company\u2019s first implementation of the WS-Federation protocol it developed with IBM. Microsoft has positioned WS-Federation as the linchpin for integrating security infrastructures between companies.Also part of R2 is branch office support so servers can be remotely managed from a central location. The ISA Server Service Pack 2 is meant to enhance that capability with support for Microsoft Update and BITS caching, HTTP compression and application traffic prioritization.R2 also features integration of services for Unix into the core operating system, new storage management features, support for the .Net Framework 2.0 and enhancements to the Windows SharePoint Services collaboration technology.Under the new virtualization-licensing plan, 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. Users can run any Windows server version within those VMs, including NT and Windows 2000. Also, with every licensed copy of Windows Server 2003 R2, Enterprise Edition, that users buy they can buy Virtual Server 2005 R2 Enterprise Edition for $99 until June 30.Microsoft also changed its Windows Server System Midsize Business Promotion to include R2 Standard Edition. The promotion includes a 20% discount off Open volume licensing contracts that include the combination of Windows Server 2003 R2 Standard Edition, Exchange Server 2003 Standard Edition, MOM 2005 Workgroup Edition, and 50 client access licenses (CALS). Microsoft also has updated its Branch Office Infrastructure Guidance (BOIS) that includes an updated architecture planning model, new templates and instruction on how to take advantage of ISA Server 2004 SP2.Microsoft said the R2 operating system is now available through OEMs including Dell, HP and IBM.Retail pricing for the Standard Edition is $999 (with five CALS), the Enterprise Edition is $3,999 (with five CALS), and the DataCenter version is not priced for retail sale since it is only available from qualified OEMs.