Windows RT is an operating system for mobile devices developed by Microsoft. It is essentially an edition of Windows 8.x built for the 32-bit ARM architecture (ARMv7). First unveiled as a prototype in January 2011 at Consumer Electronics Show, the Windows 8 RT operating system was officially launched alongside Windows 8 on October 26, 2012, with the release of three Windows RT-based devices, including Microsoft's Surface tablet. Unlike Windows 8, Windows RT is only available as pre-loaded software on devices specifically designed for the operating system by OEMs.