OpenDarwin

What is Darwin?

As the core OS of Apple's Mac OS X, Darwin is probably the most widely-used open source project designed for the PowerPC architecture.  It incorporates the Mach kernel into a powerful BSD-compatible operating environment.  Literally millions of users depend on Darwin on PowerPC for tasks ranging from surfing the web to operating massively parallel or distributed computing tasks.

What is OpenDarwin?

>From the OpenDarwin website (at http://www.opendarwin.org):
"OpenDarwin.org, jointly founded in April 2002 by Internet Systems Consortium, Inc. (ISC) and Apple, is an attempt to take cooperative Darwin development to the next level. Membership in the OpenDarwin project and access to its works are open to everyone. The project is also fully independent, with control over its own web site, project news, bug tracking information and CVS repository, as well as any other services that the community owners may wish to provide. Neither Apple nor ISC take any responsibility for, or exercise any editorial control over, the OpenDarwin project.
"[...]The mission of the OpenDarwin project is to innovate and explore new technologies while still remaining relevant, through its informal connection to www.opensource.apple.com, to the mainstream computing environments that Apple provides. It complements Apple's infrastructure by allowing increased participation by the community."

So it's a free version of Mac OS X?

No; Apple add their own private, closed-source software to Darwin to create the Mac OS X distribution.  For instance, the windowing system and user interface (Aqua) from Mac OS X are not part of Darwin, and it is not possible to take a graphical application from Mac OS X and run it on a Darwin or OpenDarwin installation.  X11 windowing systems such as Xorg and XFree86 can be used on Darwin, but these will neither provide the Aqua user interface nor the ability to run Cocoa or Carbon applications from Mac OS X.

What do the OpenDarwin people do?

As well as working on the core Darwin operating system and providing releases of the OpenDarwin operating system, a number of additional projects have been created to help fulfil the OpenDarwin mission.  These include DarwinPorts (at http://darwinports.opendarwin.org/), a ports tree containing close to two-thousand pieces of software of open-source applications; osx2x (at http://www.opendarwin.org/projects/osx2x/) which allows a Mac running OS X to control remote machines over X11 or VNC connections; and various others. Furthermore there are quiet a few projects that enhances the Darwin-/OpenDarwin experience, like OpenAudio (http://www.opendarwin.org/projects/OpenAudio/) and the extensible archiver, xar (http://www.opendarwin.org/projects/xar/).
OpenDarwin is run independently of Apple so contributors are free to work on anything they deem important, useful or fun ;-).

How can I find out more or contribute?

The http://www.opendarwin.org/ website is the best place to start, as it contains information about the current state of play, HOWTOs and FAQs on many areas of OpenDarwin and the current Todo list (http://www.opendarwin.org/cgi-bin/todo.cgi).  OpenDarwin also has a number of mailing lists (http://www.opendarwin.org/mailman/) where discussion of the multitudinous aspects of OpenDarwin is carried on.