Ballmer made the announcement in Tokyo, speaking to an audience of software developers. Observers had been expecting the next version of Windows next year, but this is the first time that the company has officially confirmed the 2012 date. Ballmer told the developers, "as we look forward to the next generation of Windows systems, which will come out next year, there's a whole lot more coming," according to a .

"As we progress through the year, you ought to expect to hear a lot about Windows 8. Windows 8 slates, tablets, PCs, a variety of different form factors," he added.

This is also the first time Microsoft has officially confirmed the Windows 8 name.

A 2012 release date would put Windows 8 about three years behind Windows 7, which came out in July 2009. Microsoft expects to sell more than 350 million copies of Windows 7 this year, and the company has traditionally relied on new versions of its operating system to spur sales.

The OS is expected to have an updated user interface and will support low-power ARM chips, a move designed to give Microsoft a fighting chance in the emerging tablet computing market.