Still, there will likely be much for developers to learn, and Microsoft announced a new conference, called Build, that will take place in Anaheim, California, in September, where developers can learn how to program for the new OS. "Space is limited and registration is open right now," Angiulo said.
Microsoft has also said that Windows 8 -- which it continued to refer to on Thursday as a "code name" -- will run on ARM-based processors from the likes of Qualcomm and Texas Instruments, as well as on the x86 platform from Intel and AMD, as it does today. ARM chips are used in most of today's smartphones and tablets.
Angiulo showed some prototype ARM-based devices running Windows 8, and said ARM processors will not be limited to tablets. "ARM enables ultra-portable computers of all form factors," he said.
Microsoft designed Windows 8 to meet the needs of a changing computer landscape. "The trends we're facing have changed," Angiulo said. "Today we're facing trends around immersive Internet computing, ultra-portable devices, and of course touchscreens. Windows 8 is a reimagining of Windows for those trends."
Several top executives from ARM, Qualcomm and other chip vendors joined Microsoft for its press event. It also previewed the new OS a few hours earlier in the U.S., at the Wall Street Journal's D9 conference.
There was a slight shadow hanging over the event, after a Wall Street Journal report on Wednesday that said Microsoft is requiring the five biggest chip makers to each work exclusively with one PC maker, to help get Windows tablets to market quickly.
Some Taiwanese PC makers have been excluded from the initial program, according to the Journal, and it quoted Acer President Jim Wong saying the PC industry "does not belong to Microsoft, and it does not belong to Intel."
Steve Guggenheimer, who heads Microsoft's OEM division, declined to comment on the report ahead of Thursday's event. Microsoft spokespeople at the event also declined to comment.
However, Microsoft did show a prototype Windows 8 laptop Thursday from Quanta, the giant Taiwanese contract manufacturer, so it clearly is working with some big Taiwanese companies on the new software.