Third beta of Microsoft's latest server technology.
The latest version of Microsoft's Windows Server technology has been released for public testing.
Codenamed Longhorn, the software had already been through two rounds of testing before the third beta was made available as a public download.
The software was originally scheduled to ship in the second half of 2007, but Microsoft has revised the official release date to the end of the year.
The public beta contains all of the final features of Windows Server except the 'Viridian' virtualisation function.
Viridian is expected to be delayed until 2008, when it will be released as an add-on to the main Longhorn software.
Features in the Longhorn beta include an interface for the Windows PowerShell command language, server print services, Lightweight Directory Services, Active Directory and advanced Active Directory Federation Services.
The software also offers security options such as an advanced version of the Windows Firewall. The x86 version of the download is 1.8GB, and the x64 version 2.5GB.
The product has already been tested by more than 10,000 members of Microsoft's technical beta programme, who downloaded the second beta back in May 2006.
Microsoft said that it expects hundreds of thousands of users to download the latest beta.