One of the main new features in Apple's new Snow Leopard operating system has been released as open source. Apple has released the code of the userland portion of its Grand Central Dispatch technology under the Apache License, version 2. Mac OS X also has kernel support for Grand Central Dispatch, which is also released as open source via the XNU project. While we're at it, let's take this opportunity to look into exactly what Grand Central Dispatch is.
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Member since:2005-07-24
Not entirely: the Apache 2.0 license is generally considered to be unidirectionally compatible with GPLv3. This means you may take Apache2.0-licensed code, combine it with GPLv3-licensed code, and publish the result under the GPLv3. You may not publish the result under the Apache2 license, though.
http://www.apache.org/licenses/GPL-compatibility.html
http://www.fsf.org/licensing/licenses/#apache2
However, only the libdispatch part is Apache2-licensed: the kernel part (xnu) is under 'APPLE PUBLIC SOURCE LICENSE', and I haven't checked whether that's GPL-compatible. Moreover, the Linux kernel is GPLv2, not GPLv3, and whether GPLv2 and Apache2 licenses are compatible afaik is under dispute.
So libdispatch can be included in GPLv3 userland applications, and xnu can be included in the kernel if the 'APPLE PUBLIC SOURCE LICENSE' is GPLv2-compatible, which is might be.
Member since:2007-09-08
The kernel component would be pretty specific to OS X anyway - it would have to be completely reimplemented anyway to run on Linux.
The compiler parts would be under the same license as the compilers - GPL3 for GCC, and the LLVM license for clang (looks like a standard BSD-style license). No problems here.
The rest of it is userspace. There would be no licensing problems at all with the daemon, since it's independent anyway. As for any library components that need to be linked to applications, the Apache license is compatible with GPL / LGPL (in one direction), so there wouldn't be any licensing problems with integrating it with glibc, or wherever it needs to go.
I think Apple pretty much did the right thing here. It just remains to be seen how useful it is, and whether anyone puts it to good use.
Member since:2005-07-06
That is the point I think he/she was trying to get at; when he/she talks about compatibility, as you've explained, it is a one way transaction. Quite honestly it makes me laugh when GPL advocates talk about the evils of proprietary software and yet their own licence has the overtones of being proprietary given that the transaction between BSD/Apache/X11/etc is one way.
Member since:
2006-11-18
No problem for BSD systems, a BIG problem for Linux since it uses GPL which is compatible only with itself.