The company made both RTM release announcements at its Worldwide Partner Conference, being held this week in Toronto.

With the server RTM, OEMs (original equipment manufacturers) that sell Windows servers will be able to start installing Windows Server 2012 on their new units. The server operating system will be available for others beginning in September.

Expectations have been mounting for this release of the server software, to be a major update. Thus far, the pre-release early versions of the OS have been downloaded more than 500,000 times, according to Microsoft.

Microsoft has added a number of major features since the last major version of the OS, Windows Server 2008 release 2. Access control to files and processes has been strengthened. Multiple Windows Server 2012 machines can now be managed as a group, from a single console. The embedded version of Microsoft's hypervisor, Hyper-V, can now work in multi-tenant configurations. And a new file system, Resilient File System (ReFS), is designed to provide better scalability and reliability.

As with Windows 8, Windows Server 2012 the new Metro user interface.