BUILD, Steven Sinofsky said that "Windows 8 represents a reimagining of Windows from the chipset to the experience. Since this is a week focused on developers, we also detailed the bold underpinnings of the re-imagination of the Windows platform, tools, and APIs."
He said "We will show off the opportunity to build applications for all of the customers of Windows 8, no matter what type of PC they have--from tablets to laptops to convertibles to desktops."
He said "Many are interested in Windows 8 for ARM processors. Everything we showcased today at BUILD also runs on the ARM-based Windows PCs being created by ARM partners and PC manufacturers."
"Windows 8 running on ARM will ultimately be available with ARM-based hardware that you can purchase. ARM requires a deeper level of integrated engineering between hardware and software, as each ARM device is unique, and Windows allows this uniqueness to shine through."
The new development tools enable you to start today to build Metro style applications that will seamlessly run on x86 (32 and 64 bit) or ARM architectures. Even if you use native C/C++ code, these tools will enable Metro style apps to target specific hardware if you choose. As new PCs become available for testing, PC manufacturers will develop seed programs for developers.
"You probably want to try out the preview release--and you can. Starting at 8PM today, Seattle time, you can download all of the code that attendees at BUILD received. This includes 32 or 64 bit x86 builds, with or without development tools. The releases also include a suite of sample/SDK applications and the SDK (please note these are merely illustrations of potential apps, not apps that we intend to ship with Windows 8). The ISOs are linked to from http://dev.windows.com. You download with a Windows Live ID (which you might want to use to test out some of the new roaming features)," Sinofsky said.
"Upgrade from Windows 7 installation is not supported for pre-release code; only clean installs are supported. "
Here is the live presentation: