Windows 8 on a tablet may take more work than Windows 8 on a PC - While Windows 8 will still find itself home in x86 and x64 desktops and laptops, it will be a major foray into the ARM-based device space. ARM chips are what power nearly all of today's major smartphones and tablets, and that's an area that Microsoft wants Windows to invade.
Windows 8 will most certainly be there, but it'll require a bit more effort on the part system designers.
"Windows 8 running on ARM will ultimately be available with ARM-based hardware that you can purchase," said Windows president Steven Sinofsky. "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."