Microsoft SharePoint Team Blog : Operating System Requirements of SharePoint 2010

Windows version/edition (64 bit only)	SharePoint 2010 support
Windows Server 2008 R2 Foundation	No
Windows Server 2008 R2 Standard	Yes
Windows Server 2008 R2 Enterprise	Yes
Windows Server 2008 R2 Datacenter	Yes
Windows Web Server 2008 R2	No
Windows HPC Server 2008	No
Windows Server 2008 R2 for Itanium-based systems	No
Windows Server 2008 Standard	Yes
Windows Server 2008 Enterprise	Yes
Windows Server 2008 Datacenter	Yes
Windows Web Server 2008	No
Windows Storage Server 2008	No
Windows Small Business Server 2008	Yes*
Windows Essential Business Server 2008	Yes*
Windows Server 2008 for Itanium-based systems	No
Windows Server 2008 Foundation	No
Windows Vista	Developer-only**
Windows 7	Developer-only**

Microsoft SharePoint Team Blog : Operating System Requirements of SharePoint 2010

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