While the heart of Red Hat Enterprise Linux is the kernel, for many users, the face of the operating system is the graphical environment provided by the X Window System, also called X.

Various windowing environments have existed in the UNIX™ world for decades, predating many of the current mainstream operating systems. Through the years, X has become the dominant graphical environment for UNIX-like operating systems.

The graphical environment for Red Hat Enterprise Linux is supplied by the X.Org Foundation, an open source consortium created to manage development and strategy for the X Window System and related technologies. X.Org is a large scale, rapidly developing project with hundreds of developers around the world. It features a wide degree of support for a variety of hardware devices and architectures, and can run on a variety of different operating systems and platforms. This release for Red Hat Enterprise Linux specifically includes the X11R6.8 release of the X Window System.

The X Window System uses a client-server architecture. The X server (the Xorg binary) listens for connections from X client applications via a network or local loopback interface. The server communicates with the hardware, such as the video card, monitor, keyboard, and mouse. X client applications exist in the user-space, creating a graphical user interface (GUI) for the user and passing user requests to the X server.