Windows RT (for "Runtime") is a version of Microsoft's Windows 8 operating system (OS) designed for mobile devices, particularly tablet PCs. Windows RT should not be confused with WinRT, the Windows Runtime library that provides system services for Metro apps
Windows RT was originally called Windows on ARM (WOA) because it is meant to run on ARM processors. The operating system has been likened to a tablet version of Windows Phone because it features a similar tile-based UI (user interface). The OS will come pre-installed on hardware, not as a stand-alone product. The first installations of RT will be on the lower-end version of Microsoft's Surface tablet; the higher end version of the device runs a full implementation of Windows 8.
Microsoft has published a specification set that devices will need in order to run Windows RT properly. Requirements include:
- A touch screen with at least 1366 x 768 pixel resolution.
- At least 10 GB of internal storage.
- Built-in camera with an ambient light sensor, an accelerometer, a gyroscope and a magnetometer.
- At least one USB (Universal Serial Bus) 2.0 port.
- Wi-Fi and Bluetooth 4.0 connectivity.
- Controls common to most tablets such as a power switch, volume adjustments, and rotation lock/unlock.
Windows RT will ship with core versions of the most popular apps familiar to Windows users. The system will not run third-party applications unless they conform to the Windows RT standard, are approved by Microsoft and are offered in the Windows Store. Devices equipped with Windows RT will be "locked down" in the sense that users will not be able to uninstall Windows RT and replace it with any other OS.