What is X11?

I came across a discussion about a open source software for image processing (GIMP) in which there was mentioned as a drawback of it that one has to “install X11 before”.

I used indeed always to stay away from software that demands the installation of huge additional whatevers on my computer (who knows what these additional whatevers might do to my installation? a serious danger on PCs!), but this is the first time I came across such a thing in the Mac world. Which may be because I’m rather new here.

So, I’m curious: What is this “X11”? And what are the disadvantages to install it?

It’s a UNIX thing: portable underpinnings for GUI applications. Apps that use it won’t have the Mac look and feel. It’s safe to install: applications that don’t use it won’t care.


The X in X11 refers to the Xerox Corp developed Star GUI. Xerox developed this to make use of this little innovation they came up with that was call a “mouse”. Because the idiots^H^H^H^H^H^H powers in charge at the time had no real foresight they determined that there was no real value in either the “mouse or the developed environment that it requires”. So they gave it way in what appears to be one of the FIRST offerings of open source. If you look in the fine print of every modern OS Xerox is mentioned as we STILL hold legal copy write and patent on sections of ALL GUI environments.

X11 is a piece of software and associated libraries that allow developers to draw windows on your screen. OSX uses a highly modified version to draw your desktop and all its windows. The X11 package that you need for GIMP provides the STANDARD binaries (progies and libs) that are required by non-native projects that are ported from other *nix to OSX.

I would take issues with the “apps that use it won’t have a mac look and feel” line. There are apps that are native to OSX that do not have a Mac look and feel. There are X11 apps that DO have a mac look and feel. I will give you that certain things (like drag and drop of text) are different under X11 and these are likely to cause a bit of frustration.

Although OS X’s windowing environment follows many of the Xerox conventions (as does Windows, for that matter), the OS X window environment (and it’s predecessor, the NeXTStep windowing environment) doesn’t actually share code with X11.

Display Postscript was NeXTStep’s ‘attempt to replace X’, which didn’t fare too well - but it begat Quartz, which has. Quartz, the OS X windowing server, is built on a fundamentally different model to X.

X is designed around a client-server architecture, the idea being that you’d have many thin terminals running slim X client interfaces, with all the data persistence and heavy lifting being done at a piece of big iron. Quartz, on the other hand, is tightly coupled with the machine it runs on, which is one of the reasons it remains so responsive.

I digress. The reason X11 is available for OS X is exactly as above - Quartz is not X. But Darwin IS Unix. So the main thing that’s stopping you from running Unix GUI apps on OS X is the graphical layer - all other Unix variants (including Linux) use X, so OS X includes X11 optionally for running Unix applications. Simple as that :slight_smile:

As an aside, last year Apple had to pay $20 millions to IP Innovation for the old Xerox GUI patent. :wink:

Ah. Hmm. Okay… (taking notes) And where do I get this X11?


the latest version will always be available there.

A minor historical note. While the Star GUI was indeed developed at Xerox, the X windowing system was developed at and is still maintained by MIT. It was first used by Project Athena, at the time the world’s largest networked workstation installation.
en.wikipedia.org/wiki/X_Window_S … evelopment


It comes on the OS X Installation disk. Just do a custom install. :slight_smile:

Ah, okay. Yes. I’ll do that the next time I feel a strong urge to procrastinate… :laughing:

Thanks for all answers!


Don`t believe a word of what the others have told you!
X11 is a TOP SECRET prototype propulsion system for a Cephalopodic Inter-Galactic Battle Cruiser. Based on certain organic gas generation processes.
Do take care

Hey! I am a former Windows user! Of course I take maximum care whenever I install something - and old habits die hard. I backup everything before, make sure all insurances are paid, wear security gloves, keep a fire extinctor at hand… etc. The Windows Way, you know.

So, don’t worry.

Ahh…no sense of adventure…obviously :confused:

If that is the case, just be careful to only download X11 from your installation disk, or from the apple site itself. X11 is opensource, as such different versions are floating around. Installation of one of these requires de-installation before installing an apple X11 update. Pretty cumbersome if you’re not after all the little gizmos that the opensource guys have installed. :unamused:

X11 as others have noted is a networked windowing environment used extensively in Unix/Linux (and nothing at all to do with Xerox).

The Gimp, which was originally mentioned, is a Photoshop-like image processing environment. It is very powerful and almost as capable as Photoshop but (IMHO and I teach Linux courses) somewhat less friendly and sufficiently different from Photoshop that if you know one you will find the other rather annoying to use.

I don’t believe the Gimp comes in a packaged version for Macs, you have to use one of the open source packaging schemes to get all the other bits and pieces. If you are not adept at this kind of thing do not even start, it could take days. There are community packaged versions of the Gimp here darwingimp.sourceforge.net/ but beware: use of this package requires you install an update to Mac X11. I have used this package and it works fine. I now have CS3, to which I upgraded from Elements at 50% off.



Thanks for the infos. I am still not sure whether I’ll try it or not; in fact I fiddle around with images rather rarely… but sometimes I have to. Well. Guess it will happen once I am adventurous enough… :laughing: