The X Window System is a windowing system for bitmap displays. It is the standard toolkit and protocol for graphical user interfaces on Unix, Unix-like operating systems and OpenVMS, and is available for almost all modern operating systems. X provides the basic framework for a GUI environment: drawing and moving windows on the screen and interacting with a mouse and keyboard. X does not mandate the user interface — this is handled by individual programs. As such, the visual styling of X-based environments varies greatly; different programs may present radically different interfaces. X features network transparency: the machine where application programs (the client applications) run need not be the user's local machine (the display server). X originated at MIT in 1984. The current protocol version, X11, was released in September 1987. The project is led by the X.Org Foundation, and the reference implementation (X11R6.8.2) is free software under the MIT License and similar permissive licenses.