http://www.osnews.com/story/14671/MacOS_X_Linux_and_Open_Source Exploring the Future of Computing en-us Copyright 2001-2009, David Adams adam+nospam@osnews.com Fri, 10 Jul 2009 00:08:27 GMT http://www.osnews.com/images/osnews.gif http://www.osnews.com http://osnews.com/thread?126742 http://osnews.com/thread?126742 The analysis that concluded that Mac OS X has performance problems was flawed.

http://ridiculousfish.com/blog/archives/2005/06/03/mystery/
http://ridiculousfish.com/blog/archives/2006/05/16/36

The idea that there is no Darwin Intel kernel anymore is also flawed.

http://opendarwin.org/pipermail/darwinbuild/2006-February/000278.ht... Edited 2006-05-21 22:24 Sun, 21 May 2006 22:20:00 GMT donotreply@osnews.com (Alistair) Comments http://osnews.com/thread?126744 http://osnews.com/thread?126744 I don't think anyone serious ever thought that Apple would move to a GPL kernel. Even with being able to close all the Aqua stuff in userland, the GPL carries way too much baggage for Apple. It's more than just the viral effect. It's also that the GPL can be interpreted in different ways - thus, the problem with "derivative works". That's why many companies won't touch anything GPL (including LGPL, GPL+exceptions) with a ten foot pole.

However, I still think there is an opportunity for someone with resources and technical manpower to put a OSX like desktop operating system on top of the linux kernel. I'm not sure either Gnome or KDE slapped on top of various distros will ever gain that much market share. That's fine for tech geeks, but others want something different. Sun, 21 May 2006 22:25:00 GMT donotreply@osnews.com (slate) Comments http://osnews.com/thread?126747 http://osnews.com/thread?126747 There is no way in the world Apple would use a GPL kernel. BSD perhaps because of the better license, just like they did with userspace stuff.

Linux is NOT the magic bullet and will not be ubiquitous. Sun, 21 May 2006 22:31:00 GMT donotreply@osnews.com (marklar) Comments http://osnews.com/thread?126748 http://osnews.com/thread?126748 "Linux seems, to them, the most viable option"

On what grounds is it that the Linux kernel seems the most viable option Thom? Sun, 21 May 2006 22:31:00 GMT donotreply@osnews.com (chekr) Comments http://osnews.com/thread?126751 http://osnews.com/thread?126751 "-- Linux seems, to them, the most viable option."

Thom wasn't saying that. Sun, 21 May 2006 22:38:00 GMT donotreply@osnews.com (helf) Comments http://osnews.com/thread?126752 http://osnews.com/thread?126752 I'm not sure either Gnome or KDE slapped on top of various distros will ever gain that much market share. That's fine for tech geeks, but others want something different.

Yeah, considering Gnome or KDE (Gnome especially) is so very technical and hard to use.... oh wait, that's sarcasm. Have you used Gnome or KDE lately? Hell, from what I've used of Mac OS X, it almost looks like some of the UI decisions were directly ripped form GNOME. (Compare the Networking tools. Besides the order they are listed in, they are almost the exact same!) Sun, 21 May 2006 22:44:00 GMT donotreply@osnews.com (leech) Comments http://osnews.com/thread?126758 http://osnews.com/thread?126758 It's really just getting boring, the whole "Linux + something = Magic Fairy Dust" articles. It's good for a fight, and it's good for people that want a Linux-based monoculture, but for normal or intelligent people? Just lots of hot air.

I know a ton of unixy people that use OS-X. Not one of them is running a custom kernel. Why would they? The only thing I've seen of note was a hacked kernel that let you run an ibook with the lid closed...

Please, prove me wrong and show me a nice repository of people talking about the cool things they do to xnu... I'm still all on PPC, so maybe I'm missing out. Sun, 21 May 2006 22:48:00 GMT donotreply@osnews.com (bubbayank) Comments http://osnews.com/thread?126759 http://osnews.com/thread?126759 Thanks for the column Thom.Was an insightful read. Sun, 21 May 2006 22:48:00 GMT donotreply@osnews.com (Bajan) Comments http://osnews.com/thread?126761 http://osnews.com/thread?126761 Those blog entries are largely worthless:
# They claim that making a new thread is called "forking". No, it's not. Calling fork() is forking, and fork() makes processes, not threads.
That's not true. The article did make some, somewhat, confusing references to processes as a "thread of control." However, this isn't a fallacious way to describe it either.
What they actually said was:

The Unix process/thread creation is called "forking" as a copy of the calling process is made.
This is a correct description of fork().
fork() creates a child process that differs from the parent process only in its PID and PPID, --taken from GNU's man page on fork.

I admittedly stopped reading there because it was obvious the author has a bias against the other authors causing him to incorrectly read their results. In other words: If he could read that bit about fork wrong I doubt he could understand any of their more complex arguments.


The second article was interesting. However, the realities of the default allocator Apple has chosen to use for OS X are real and valid; and they are an issue. The article has serious merit for finding a good explanation and showing its advantages though. Sun, 21 May 2006 23:02:00 GMT donotreply@osnews.com (ma_d) Comments http://osnews.com/thread?126762 http://osnews.com/thread?126762 On what grounds did you decide to not read TFA?

Thom issued every reason why Apple is not going to use the Linux kernel as their replacement for their current solution. That snippet of text you quoted should've included the first portion of the sentence, which stated that "some have uttered" (obviously meaning various 3rd parties!!!) that Apple might replace their current BSD kernel with the Linux kernel.

Thom did not allude to Apple wanting to do it. Sun, 21 May 2006 23:03:00 GMT donotreply@osnews.com (DittoBox) Comments http://osnews.com/thread?126763 http://osnews.com/thread?126763 Define "better." If you don't; you're trolling. Sun, 21 May 2006 23:03:00 GMT donotreply@osnews.com (ma_d) Comments http://osnews.com/thread?126766 http://osnews.com/thread?126766 Never say never! No one knows the future.

But I would bet 100 USD, that Apple will not switch to the Linux kernel on their desktop system (not in the near future. Server is another beast). Why should they? They will probably not sell much more units because of a Linux kernel and Thom has absolutly right: Apple likes control (what comercial company does not like control in one way or the other?). Sun, 21 May 2006 23:08:00 GMT donotreply@osnews.com (SteveB) Comments http://osnews.com/thread?126769 http://osnews.com/thread?126769 That's definitely true. I doubt many Apple purchasers would freak over it running Linux. Sun, 21 May 2006 23:18:00 GMT donotreply@osnews.com (ma_d) Comments http://osnews.com/thread?126771 http://osnews.com/thread?126771 Mac OSX switching to the Linux kernel is almost a non sequitur in the context of the argument given, as no part of the cited criticisms of Darwin or Mac OSX would be directly addressed by the change. So, let's just chalk that one up as pandering for page hits.

The issues regarding the ability to compile custom kernels for Darwin, however, are worth some discussion. I don't know much about Darwin, XNU, or the Mach microkernel, and therefore I'm not sure how (or if) users may select or remove support for various hardware or software features. However, most UNIX-like systems have some notion of kernel extensions or modules that may be loaded, if not dynamically, when the kernel is loaded into memory.

If this is the case for MacOSX/Darwin/XNU, then I don't understand what the huge stink is over compiling a custom kernel. It seems to me that the needs of most power users and system administrators are met by configuring which kernel extensions and/or device drivers are loaded. Since the system is based on a layered design with a microkernel at the heart, there must not be a significant benefit to slimming kernelspace.

With this in mind, I think that moving to Linux would be a step backwards from Darwin. As much as I enjoy running Linux and rolling my own kernels, there's no way to slim it down to the size of a maximally configured Mach microkernel, probably even if you remove the virtual memory manager (possible with 2.6.x). As much as dynamic module management on Linux has improved with initrd, coldplug, hotplug, and udev, there are still issues when using a fully modular kernel. For example, my ACPI modules (battery, button, etc.) never load automagically, so I compile them statically. Further, while Darwin has some nested wrappers for things like threading, Linux has some even crazier code paths for things like context switching, where execution passes in and out of arch-specific code a few times.

If Apple or its developer community really feels pressure to move away from Darwin (for some reason I fail to realize), they might as well choose a system with a more modern, aggressive design than Linux. I'd much rather see Mac OSX based on L4, MINIX3, or Dragonfly, all of which are open source. Sun, 21 May 2006 23:34:00 GMT donotreply@osnews.com (butters) Comments http://osnews.com/thread?126773 http://osnews.com/thread?126773 I don't know anyone (and I know a bunch of Mac OS X users) careing about the underlaying kernel. Mac OS X is just the best OS on earth to them. If it would be a Linux kernel or the current kernel or another kernel... they don't care as long as the system works. That's it. I have never heard of any one of them switching the kernel or compiling a custom made kernel. And some of them (I would say 50%) are absolutly in the position/knowledge to do so. But they don't do it and probably will never do. Sun, 21 May 2006 23:38:00 GMT donotreply@osnews.com (SteveB) Comments http://osnews.com/thread?126775 http://osnews.com/thread?126775 Better=More Freedom Sun, 21 May 2006 23:42:00 GMT donotreply@osnews.com (BBlalock) Comments http://osnews.com/thread?126777 http://osnews.com/thread?126777 Yeah, considering Gnome or KDE (Gnome especially) is so very technical and hard to use.... oh wait, that's sarcasm.

My comment had nothing to do with the usability of KDE or Gnome. I was talking about some geeks not worrying about market share - while others with interests in various projects do.

But there's a point to be made about developing a desktop operating system as a whole (from an organizational standpoint), and not relying on various upstream/downstream parties putting it together. Sun, 21 May 2006 23:49:00 GMT donotreply@osnews.com (slate) Comments http://osnews.com/thread?126778 http://osnews.com/thread?126778 Linux would be a bad idea for 2 reasons. Firstly, its GPL - which isn't always a bad thing however with proprietary software it is (please no GPL, BSD wars - its been covered too many times)

Secondly, linux goes by the philosophy of get it working on every peice of hardware right away and worry about performance and stability later.

Personally I think they should just take FreeBSD as a whole, make their graphical and window servers for it, and add their obj-c layer to it. Scrap the XNU/Mach stuff - just go FreeBSD + Apple's GUI and hardware. Just my opinion though. Sun, 21 May 2006 23:55:00 GMT donotreply@osnews.com (ValiantSoul) Comments http://osnews.com/thread?126789 http://osnews.com/thread?126789 Well, companies don't have problem touching (L)GPL in Europe or Asia. It must be a local US thing, and therefore pretty much irrelevant for the rest of us. Mon, 22 May 2006 00:23:00 GMT donotreply@osnews.com (dylansmrjones) Comments http://osnews.com/thread?126790 http://osnews.com/thread?126790 More freedom?
For everybody or just for you?


The only way to gain more freedom is to take it away from somebody else. Mon, 22 May 2006 00:24:00 GMT donotreply@osnews.com (dylansmrjones) Comments http://osnews.com/thread?126791 http://osnews.com/thread?126791 I don't believe in the control argument. Please correct me if I am wrong but Apple can do what ever they want to the Linux kernel if they make a fork as long as they make these changes GPL. They have as much control as with anything BSD. Obviously the GPL can be a problem for a company, but it doesn't limit their control if they did adopt the Linux kernel.Edited 2006-05-22 00:30 Mon, 22 May 2006 00:27:00 GMT donotreply@osnews.com (TechniCookie) Comments http://osnews.com/thread?126793 http://osnews.com/thread?126793 Wouldn't things get a little tricky though when they start writing stuff with IOKit that interacts with the kernel, and other related things? Some of their proprietary, closed source, stuff would have to then be GPLd wouldn't it? Mon, 22 May 2006 00:34:00 GMT donotreply@osnews.com (ValiantSoul) Comments http://osnews.com/thread?126795 http://osnews.com/thread?126795 A lot of your argument is invalidated by the fact that the Linux and Darwin kernel architectures are the same. Darwin/XNU is not microkernel-based; the only part of the kernel that is dynamically loadable is drivers, just like Linux. Honestly, I can't think of any part of Darwin/XNU that I would choose to remove anyway. Mon, 22 May 2006 00:47:00 GMT donotreply@osnews.com (Wes Felter) Comments http://osnews.com/thread?126796 http://osnews.com/thread?126796 Yes, Linux is, for them, the most viable option to get OSX Aqua GUI for free, by injecting the GPL virus infected Linux kernel to OSX. Mon, 22 May 2006 00:50:00 GMT donotreply@osnews.com (Babi Asu) Comments http://osnews.com/thread?126803 http://osnews.com/thread?126803 In this case, even if Apple removes access to the parts of the code they are modifying, this is more freedom for everybody without taking any freedom from anybody else.

Please remember that the original code that Apple forked from is still available and will always be available for anyone to use. All Apple can do is restrict access to the bits they add/change. Mon, 22 May 2006 01:17:00 GMT donotreply@osnews.com (BBlalock) Comments http://osnews.com/thread?126805 http://osnews.com/thread?126805 I don't think Apple would ever use Linux as their kernel...

...But in the a parallel reality that it might happen, Apple would probably fork the main tree and add to "their" kernel a stable interface. The kernel would probably get more and more different from the main tree as time passes, but Apple would back-port everything they want/need into their tree.

The thing is, so many developers want a stable kernel interface, but Linux kernel developers don't want to spend their time doing this. Reasons may vary... from the open source nature of the development to the political GPL 'defense'....

The other thing is, this kernel with stable interface would rise many interest from developers looking for those... with hardware developers in the first place of the line...


Actually, it's not very different from the KHTML/WebCore history... Mon, 22 May 2006 01:19:00 GMT donotreply@osnews.com (JrezIN) Comments http://osnews.com/thread?126807 http://osnews.com/thread?126807 Yes, but that's also going to give less freedom to the rest of us (not that I care much. I just want Cocoa documented Mon, 22 May 2006 01:25:00 GMT donotreply@osnews.com (dylansmrjones) Comments http://osnews.com/thread?126824 http://osnews.com/thread?126824 "A lot of your argument is invalidated by the fact that the Linux and Darwin kernel architectures are the same. Darwin/XNU is not microkernel-based; the only part of the kernel that is dynamically loadable is drivers, just like Linux."

Darwin is based on the Mach microkernel, but now that I've read more about it, the POSIX layer, proc, vmm, and fs are loaded in kernelspace along with Mach. So it is a hybrid kernel.

Unlike Linux, though, many (most?) device drivers are loaded into userspace and use microkernel-style message passing to request access to kernel interfaces and data structures. So, for example, Darwin has a stable device driver interface specified by its message dictionary and lacks the ABI problems that plague binary Linux drivers.

So, for what it's worth, Darwin/XNU and Linux are more similar than I originally thought, but switching to Linux would still be a small step backward in terms of architectural sophistication (plus the stability, reliability, and debugability that should theoretically go along with that).

Thanks for correcting me Mon, 22 May 2006 03:40:00 GMT donotreply@osnews.com (butters) Comments http://osnews.com/thread?126825 http://osnews.com/thread?126825 There is a developer package in mac installation cd, contains developer tools including documentation. You can view it online on http://developer.apple.com/. There is GPL implementation of Cocoa called GNUStep, but compared to Cocoa it's just plain suck. Mon, 22 May 2006 03:44:00 GMT donotreply@osnews.com (Babi Asu) Comments http://osnews.com/thread?126826 http://osnews.com/thread?126826 I'm perfectly aware of GNUstep. What do you think I'm running in exactly this moment?

GNUstep doesn't suck from a technical point of view, but one must remember that it is far from finished.

Cocoa contains proprietary extensions to OpenStep API, and these I'd like to see the documentation for. Mon, 22 May 2006 04:02:00 GMT donotreply@osnews.com (dylansmrjones) Comments http://osnews.com/thread?126829 http://osnews.com/thread?126829 About time to revise the ancient GPL license model into something similar to the BSD license model if you ask me. Mon, 22 May 2006 04:12:00 GMT donotreply@osnews.com (netpython) Comments http://osnews.com/thread?126831 http://osnews.com/thread?126831 Why? The GPL is fine for programmers who don't want to allow thier code to be forked into closed source derivitives.

If the new GPL doesn't serve those folks needs they'll either use the old GPL or they'll roll thier own license.

Besides, if the GPL is altered to be largely identical to the BSD license then one of them is redundant. Mon, 22 May 2006 04:22:00 GMT donotreply@osnews.com (BBlalock) Comments http://osnews.com/thread?126838 http://osnews.com/thread?126838 Yes, Linux is, for them, the most viable option to get OSX Aqua GUI for free, by injecting the GPL virus infected Linux kernel to OSX.

*sigh*

A GPL kernel does not necessitate a GPL userspace. Would make it very difficult for that multi-billion dollar industry that has sprung up around linux to exist, since most of the commercial products from companies like IBM or Oracle are closed and proprietary.

Apple was happy enough to embrace the GPL when they needed to lift khtml for Safari. I don't see anyone demanding they hand over the source for OS X in return.

edit: typoEdited 2006-05-22 05:14 Mon, 22 May 2006 05:12:00 GMT donotreply@osnews.com (elsewhere) Comments http://osnews.com/thread?126839 http://osnews.com/thread?126839 >Some of their proprietary, closed source, stuff would have to then be GPLd wouldn't it? Mon, 22 May 2006 05:15:00 GMT donotreply@osnews.com (re_re) Comments http://osnews.com/thread?126840 http://osnews.com/thread?126840
The Unix process/thread creation is called "forking" as a copy of the calling process is made.
This is a correct description of fork().

I know of nobody who uses fork for thread creation. Processes and threads are substantially different (otherwise why bother?). The Anandtech article benchmarks fork in order to explain poor thread creation. This does not stand to reason, as the standard way of creating threads on Mac OS X is pthread_create. Yes, Apple uses POSIX threads, which practically all *nix systems use, so to be ignorant of that fact severely casts doubts on the credibility on anyone who uses fork to create "threads". Mon, 22 May 2006 05:44:00 GMT donotreply@osnews.com (evangs) Comments http://osnews.com/thread?126841 http://osnews.com/thread?126841 I am surprised nobody mentioned opensolaris (www.opensolaris.org) as a viable kernel alternative for Mac OS X x86. The CDDL license would protect any Apple derivative work while providing an enterprise class unix kernel used in the largest data centers of this world.
I do admit that the PPC port is required and that the effort is probably not worth it, at least for the next coming years, while Apple support PPC. Mon, 22 May 2006 05:55:00 GMT donotreply@osnews.com (sebsto) Comments http://osnews.com/thread?126842 http://osnews.com/thread?126842 I know of nobody who uses fork for thread creation.

The use of fork for thread creation dates back to the early 60s. Scheme still calls it's thread creation operations "fork-thread".

Basically, there are two models for generating separate thread-of-control elements in a program. Those in which an existing thread-of-control is duplicated in part and returned to twice are usually called "forking" schemes, while those in which a thread-of-control object is created and activated are used so seldom any more I can't recall what they're called.

We tried to accomodate both in pthreads. Mon, 22 May 2006 05:56:00 GMT donotreply@osnews.com (Cloudy) Comments http://osnews.com/thread?126844 http://osnews.com/thread?126844 KHTM is LGPL not GPL , its two different license.

http://en.wikipedia.org/wiki/KHTML Mon, 22 May 2006 06:09:00 GMT donotreply@osnews.com (Moulinneuf) Comments http://osnews.com/thread?126846 http://osnews.com/thread?126846 The problem boiled down to this: can those drivers be considered derivative works, or not?

*Sigh* No, that's not the issue. The problem boils down to: does Linux + proprietary drivers constitute a derivative work of Linux or is it "mere aggregation"?

http://www.gnu.org/licenses/gpl-faq.html#MereAggregation Mon, 22 May 2006 06:20:00 GMT donotreply@osnews.com (zerblat) Comments http://osnews.com/thread?126853 http://osnews.com/thread?126853 *Sigh* No, that's not the issue.

Isn't that what I'm saying? Mon, 22 May 2006 06:59:00 GMT donotreply@osnews.com (Thom_Holwerda) Comments http://osnews.com/thread?126855 http://osnews.com/thread?126855 Are you sure, if Apple use linux kernel, Apple proprietary user interface will be considered as "mere aggregation"? I don't think so. Mon, 22 May 2006 07:31:00 GMT donotreply@osnews.com (Babi Asu) Comments http://osnews.com/thread?126859 http://osnews.com/thread?126859 Uhh, yes? Seriously, Linux himself said that userland programs are not 'derivative works', and are considered fair use of the kernel. The gray area lies with drivers, userspace is totally clear. Mon, 22 May 2006 08:45:00 GMT donotreply@osnews.com (maxx_730) Comments http://osnews.com/thread?126860 http://osnews.com/thread?126860 GPL is not an issue here. Apple already uses {L,}GPL products such as khtml and kjs, GCC ( important one.. ) and samba.
Plus, you can load binary blobs into the linux kernel, as Linus explicitly said.

So please, Thom, stop your stupid GPL FUD, this is a technical issue, not a licencing one.

Thanks. Mon, 22 May 2006 08:45:00 GMT donotreply@osnews.com (what) Comments http://osnews.com/thread?126862 http://osnews.com/thread?126862 Plus, you can load binary blobs into the linux kernel, as Linus explicitly said.

Don't lie. Linus said he only approves of binary drivers that were written without Linux in mind. Anything else he considers derivative works. Mon, 22 May 2006 09:16:00 GMT donotreply@osnews.com (Thom_Holwerda) Comments http://osnews.com/thread?126879 http://osnews.com/thread?126879 So what ?
How can you prove what was in a developper's mind ? You release linux-specific parts under the GPL and the binary blob... Just like Nvidia and ATI do.

Again, this is a technical issue, IMHO. Mon, 22 May 2006 11:15:00 GMT donotreply@osnews.com (what) Comments http://osnews.com/thread?126894 http://osnews.com/thread?126894 The analysis that concluded that Mac OS X has performance problems was flawed.

http://ridiculousfish.com/blog/archives/2005/06/03/mystery/
http://ridiculousfish.com/blog/archives/2006/05/16/36

And a few postings on a few specific issues (and dubious ones at that, on forking amongst others) on a blog proves otherwise? The hard figures as to Mac OS X's generally poor performance in a variety of scenarios are there. The question as to why is a slightly more complex matter to explain.

The idea that there is no Darwin Intel kernel anymore is also flawed.

Really? That mail posting says nothing. The other mail posting quoted elsewhere only seems to confirm what others have said. They will continue to release PPC kernel sources for as long as they last (no mention of the Intel sources at all), and it carefully skipped around by saying 'non-kernel Intel sources'. That's a pretty decent confirmation in my book, unless of course, Apple confirms otherwise.

Booting PPC sources was never the point.Edited 2006-05-22 14:31 Mon, 22 May 2006 14:20:00 GMT donotreply@osnews.com (segedunum) Comments http://osnews.com/thread?126915 http://osnews.com/thread?126915 Yea, they shouldn't have used that to benchmark thread creation as it's a whole lot more than creating a thread (although it is technically creating a new thread, inside a new process).

Anyway, I don't know of any benchmark for thread creation speed. You might try running a single pthread program to benchmark between the two; or suggest it to anandtech.

I still believe it may have a strong correlation. Explaining why processes take longer to create on OS X would be a good start in really debunking their method. Mon, 22 May 2006 17:23:00 GMT donotreply@osnews.com (ma_d) Comments http://osnews.com/thread?126918 http://osnews.com/thread?126918 He didn't say that. He said that if they are written without Linux in mind than that implies they aren't a derivative work.
You've twisted that to be that they are not derivative if and only if they weren't written with Linux in mind.

If he's said what you're saying I'd love to see it because I've read his discussions about it and he didn't say iff. Mon, 22 May 2006 17:28:00 GMT donotreply@osnews.com (ma_d) Comments http://osnews.com/thread?126927 http://osnews.com/thread?126927 Seriously, anyone? Buehler?

If we're going to argue about it, I'd love to see at least one person here pissed off because they cannot do something they used to be able to do (build their own kernel).

Thom, how about a nice news story where you track down people doing this and wow us with neat Xnu tricks? Mon, 22 May 2006 17:59:00 GMT donotreply@osnews.com (bubbayank) Comments http://osnews.com/thread?126961 http://osnews.com/thread?126961 "Linux himself said..."

Are you personifying the OS now, or is this just a simple typo? *evil grin* Mon, 22 May 2006 19:24:00 GMT donotreply@osnews.com (chewie) Comments http://osnews.com/thread?127093 http://osnews.com/thread?127093 People are just not getting the multiple layers that go into OS X that will be Apple only layers. Let's not forget the dichotomy between Linus and the history between Apple Engineering and him.

To put it bluntly: Apple will never use Linux and what they add to XNU for Leopard will most certainly copied. Tue, 23 May 2006 04:17:00 GMT donotreply@osnews.com (tyrione) Comments