As with other operating systems, there are specific hardware requirements of Windows 8 certified devices. These requirements are so Microsoft can guarantee a certain level of experience for all those who use its coming flagship on tablets and convertible PCs. These requirements include 5-point multitouch, NFC “touch marks,” five specific hardware buttons, a new Ctrl+Alt+Del combination, two second resume, and more.
The NFC "touch marks" mean there is something marking where devices need to be in contact in order for NFC to work. The five required buttons are Power, Rotation Lock, Volume Up and Down, and the Windows Key, which must be at least 10.5 mm in diameter. Other requirements include there being a minimum 10 GB of free space after the out-of-box experience, a 1366x768 screen resolution, and a 720p camera. For ARM machines the bootloader is also to be locked, which will prevent such devices from having other OS’s installed (until someone figures out how to get around that).