Sinofsky is expected to offer up more information about Windows 8 during the keynote, building on the he gave at June's All things Digital conference, and the posts he and others at Microsoft have published on the "Building Windows 8" blog since mid-August.

Microsoft has been mum about a release schedule for Windows 8, but the timing of Sinofsky's return to blogging and the anticipation that the company will provide developers with a preview edition Tuesday may hint at a timeline similar to 2009's Windows 7.

In the run-up to Windows 7, Microsoft gave attendees at a similar developer conference an early build almost exactly a year before it officially launched the OS. That same day, Microsoft promised it would offer a of Windows 7 within months, which it did Jan. 10, 2009.

The speaker slate for BUILD suggests that Microsoft will devote Tuesday's presentation to Windows 8 on desktops and tablets, while Wednesday's will focus on Windows 8 Server, and developer tool upgrades and changes.

Microsoft will post links to the webcasts on the shortly before they begin, said Kyle today.