Is Mac OS X open source?

Question

I learned recently (on superuser) that Mac OS X uses the bash shell. I also know that OS X has a UNIX core.

I was searching for information about OS X and Open Source on google, but what I found was this site:

http://www.opensource.apple.com/

Which seems to include the source code for OS X.
For instance, one of the links reads: Mac OS X 10.5.7 Source

So, is OS X open source?

There's an Apple Public Source License, but I'm bad at understanding legalese.

Update

Extra/Bonus question:

Besides the kernel, What about the various other pieces? The X server? Window Manager? File explorer? etc. What's open source and what's not?

Answer 1

Darwin is open source operation system from Apple and it's core of Mac OS X. But Darwin hasn't Mac OS X GUI.

• Darwin is like Linux, FreeBSD, etc...
• Mac OS X GUI is like KDE, GNome, etc...

Answer 2

Others have already explained that Darwin is open source. It's Mac OS X's kernel, similar to how Linux is the kernel of a Linux distro. Mac OS X's windowing system (called Quartz Compositor) is not open source.

You also ask about other open source parts of Mac OS X:

Besides the kernel, What about the various other pieces? The X server? Window Manager? File explorer? etc. What's open source and what's not?

One of the most prominent Apple open source projects is probably WebKit, which was originally a fork of KHTML and KJS. WebKit is used by a huge number of browsers.

Another Apple open source project you may have used even if you don't use Mac OS X is Bonjour, Apple's implementation of Zeroconf.

Apple also owns CUPS, a printing system that is used by a number of operating systems.

Apple also has a number of other open source projects, such as a streaming server, and they contribute to many more open source projects, such as gcc. You'll find more at opensource.apple.com and Mac OS forge. In addition to that, Mac OS X ships with hundreds of open source components from Apache to ZFS, most of which are not owned or maintained by Apple.

Answer 3

To put it simply: The kernel is open source; the user interface and all the applications that the OS comes with are not.

Apple does maintain some open source projects, but for the most part, everything besides the core kernel is closed source. For example, WebKit (the HTML rendering engine behind Safari, Google Chrome, and other browsers) is open source; however, the Safari browser itself is not. Finder, Spotlight, and most (if not all) of the applications that come with the OS are closed source.

Answer 4

From wikipedia

Apple released this set of software as a free and open source operating system named Darwin. On top of Darwin, Apple layered a number of components, including the Aqua interface and the Finder, to complete the GUI-based operating system which is Mac OS X

Answer 5

(Since I don't have the rep to comment on MicTech's answer...)

Darwin is open source, OS X as a whole is not.

Answer 6

A few parts of OS X are open source (most notably the Darwin kernel), and it uses many open-source projects.

The "Mac OS X 10.5.7 Source" title is a bit misleading - the page lists all the open-source code used in OS X (such as Apache, Python, bash, etc)

Not much of what you probably consider "OS X" is open source - it's mostly underlying things (for example, the kernel, or the the SMB client/server used by the Windows-file-sharing feature)

Answer 7

The Darwin OS, upon which OS X is based, is open source, as is the XNU kernel it uses. OS X's Aqua GUI is not open source, however. This effectively gives Apple the best of both worlds: they get an OS that has the stability and security of an open source, UNIX-like platform, while also having the profitability of a proprietary platform. This is like the McDonald's policy of giving you free water and charging you a quarter for the cup.