What is X, XFree, XOrg or X Windows?


What X is Not:

  • X is not a product by Microsoft with the letter X before it.
  • X does not affect the way graphical windows on your screen look
  • X won’t let you browse through files in a graphical manager
  • X is NOT a GUI (Graphical User Interface)
  • X doesen’t sound like it does a lot, does it? Well read on to find out why it’s an essential part of Linux!

What X does:
X11 (and it’s variants, XOrg, XFree86 etc) is the layer between the hardware on your system (your graphics card, and so on) and the GUI that sits on top of X. Have a look at the following diagram to get the general idea:


When a program is started up, it goes through the process of first talking to the GUI, about what to do with it’s windows, ie: placement, focus and so on. The GUI applies it’s thoughts to the process, applies the look, menubars (File, Help, Close, Minimise, etc), and all decorations to the window, then passes it to X. X has the final decision on where it places it on a screen. It then talks to the hardware, making it issue the process.

Tux, The Linux Mascot

    Tux says: GUI stands for Graphical User Interface, and comprises of things like icons, menus, pointers and windows. It is usually pronounced ‘Gooey’.

Without X in the equation, the GUI that you use, or properly termed: the Window Manager couldn’t do anything.
X Is also a server. We usually refer to it as XOrg or just as X, but indeed it’s proper title is an X Window Server. When you run X on your own linux box, X has to determine whether you want to display it on a local machine and on a local monitor, or on a remote monitor. You can also have more than one X session running on your linux box at the same time. If you have 2 monitors, and a dual headed graphics card (ie: Matrox G400 DH), you can get X to display Jane’s X session on monitor 1 and Bob’s X Session on monitor 2, all running on one computer, at the same time. Show me Windows Vista do that, please 🙂

Some X Heritage
If you’re interested in knowing how X came to be, this chapter is for you.
X was an idea concieved by many: In 1984, Apple had released it’s first graphical user interface. If you were either too young, or never saw it. I reckon you should definitely take a look at the 1984 TV advertisment of the first Macintosh. It’s a wonderful piece of art. You can see this great piece in computing history HERE, alhthough be weary- it’s around a 13MB quicktime movie– you’ll need a fast connection if you want to see it in the next hour!
Even prior to this, a group of real boffins with some way far-out ideas (circa 1978) had been stroking their beards, drinking lots of hi-caffeine coffee and creating the very first GUI. It was made by the researchers in Xerox’s PARC (Paulo Alto Research Center), where they designed a GUI called Exlir, and terminal systems to go with it (called the Star). Unfortunately, it was not a commercial sucess, mainly due to high pricing.

Anyways… After Elixir, a few GUIs appeared (amongst others): Digital’s GEM, Atari’s TOS and the most famous of all, The Mac System OS, in 1984. Less than two years later in 1986, a consortium of UNIX developers including Sun Microsystems , Silcon Graphics and AT&T created X. Originally it shipped with the window manager called TWM. The source of this product and who created it, are still unknown.

TWM (perhaps, Tom’s Window Manager, or, as most know it today; “THE Window Manager”), was the interface that sat ontop of X, and allowed you to open up Xterms, resize windows and do basic window manipulation. It was pretty darn basic to say the least. Then came FVWM, which was a major improvement. For Linux geeks and for people who want a really light window manager, you’ll find twm and fvwm still in use today. It still ships with all the latest distros. FVWM2 came out years later, along with other window managers such as NeXt/NeXtStep, AfterStep, IceWM, QvWM (which is supposed to look identical to Windows 98 btw), KDE, Gnome and many others. In 1990, Microsoft Windows 3.0 was released.

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