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X on X

by Chris Coleman

I read an article the other day that predicted Apple wouldn't be able to keep advanced Mac OS X users because they would learn Unix and move on to a more professional system. I disagree.

Mac OS X has built-in advantages that no other OS currently offers. It will keep the advanced users because of open-source developments that will ultimately take computing beyond anything that even Apple has imagined. Already open-source developers are extending Mac OS X beyond what Apple initially delivered.

Apple provides an excellent desktop built on top of a powerful Unix foundation and has made it easy for anyone to use. Open-source developers are taking that starting point and merging it with existing open-source technologies and creating new, wonderful things.


If you've used BSD or Linux, you're most likely familiar with XFree86. It provides the graphics engine for most open-source operating systems, including Darwin. Darwin is the core of Mac OS X and is based on BSD.

Mac OS X comes with Core Graphics and Aqua. If you run Darwin, you have to install XFree86 and your choice of window manager to get similar functionality. Because Mac OS X is based on Darwin, it's possible to shut down Core Graphics and install XFree86 to access your X11-based programs.

Comment on this articleAt this point, are exercises such as installing XFree86 truly useful? Or is the most important aspect the fact that you can do it ... leading to more important developments up the road?
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However, this doesn't really gain you anything over just downloading Darwin for free. In the May/June Issue of the Daemon News print magazine, I read an article by Torrey Lyons titled "Installing XFree86 on Mac OS X and Darwin." So, I owe most of what I know about X on X to Torrey. (Disclaimer: I am a co-founder of DN, so I get to read all the articles.) As soon as I got my iBook up and running, XFree86 was one of the first things I installed, and I was surprised at how smoothly it went.

The latest version, XFree86 4.1.0, includes all the work done by the X on X group -- nothing extra to worry about. Darwin and OS X don't require an XFree86 configuration file. Actually, configuration at that level is not possible because XFree86 uses Apple's IOKit drivers. Although, this means that there must be an IOKit driver for your video card.

X on X is the work of a group of open-source developers who wanted to make the most of XFree86 on OS X. Their modifications allow XFree86 and Core Graphics to co-exist. Currently when you boot up XFree86, it puts an "XDarwin" icon in your applications folder. Clicking that icon will start XFree86 in a separate screen, almost like a virtual terminal. It will read .xinitrc from your home directory and start your favorite window manager. From this point, you can run all your favorite X Window applications.

By pressing command-alt-a, you can return to your Aqua desktop. The key sequence is customizable. The X on X project is working on a "rootless" X Server. Right now, the X Server is "rooted" in the separate virtual terminal. When the X on X project succeeds with a rootless X Server, you will be able to have windows from X and Aqua on the same screen.

This sort of flexibility isn't possible in the world of closed source. Apple made a very smart move when it opened up its base operating system.

So far, I am very pleased with Mac OS X. There's still room for improvement, but I like what is available so far. I haven't lost my BSD, and I've gained a professional GUI.

Chris Coleman is the Open Source Editor for the O'Reilly Network and is actively involved with community projects such as and Daemon News.

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