[macdummy]

ok i admit that i'm a macdummy and a tech dummy in general. but this stuff still fascinates the heck out of me.

i was at the apple store the other day to get my ipod replaced when I was sitting at the bar enjoying a lively debate between two computer geeks.

one guy was a die-hard mac user for 10 plus years, and the other guy was also a die-hard tech geek who was a windows admin/linux user.

they had a discussion on the pros/cons of the Mac OS X kernel mach vs. the linux kernel or something or other. anyway, i wanted to hear what they both had to say but my kid was nagging me to get ice cream so i cut out shortly thereafter.

anyway, i was wondering if the experts can sort of debate this thing right here and i'll just sit back and listen.

so what are the benefits or the mach kernel vs. the linux kernel? would OS X change for the better if mach was removed for something else? how feasible is this scenario in the first place? how tough would the transition be? what does it mean for applications, would some take a performance hit/gain? is this something that you feel may be changed now with that avie guy's departure?

thanks, and i await the responses!

[msuper69]

The OS X kernel is working just fine. It has proven to be robust under real-life use. The debate is a waste of time. Of course a Linux weenie is going to promote his favorite OS as better. Swapping out the kernel of OS X at this point would be ridiculous, besides being unnecessary. Would you want a heart transplant when your heart is working just fine just because someone says this new heart is better?

If you want to learn more about OS X et. al. go to the Apple Developer Connection web site at http://developer.apple.com. There's tons of technical information there, all free.

[TETENAL]

Wikipedia discusses the Mach-kernel including its problems and there's also a short article about the XNU-kernel that OS X uses.

http://en.wikipedia.org/wiki/Mach_kernel
http://en.wikipedia.org/wiki/XNU

I don't think that applications would care about the kernel at all. If Apple wanted to change it they probably could just do it. They once changed the kernel of classic Mac OS and it caused no issues.

[Chuckit]

It would break a lot of code that uses Mach functions (NSMachPort, mach_msg_send, etc.) unless they provided a compatibility layer, wouldn't it?

[mduell]

No more mysteries: Apple's G5 versus x86, Mac OS X versus Linux and its followup No More Apple Mysteries, Part Two at Anandtech compares the OSX and Linux kernels and shows where OSX falls down (mostly server tasks with lots of threads).

Arstechnica's review of Tiger also has a page dedicated to the OSX kernel.

[P]

Apple tried to make a new kernel once. It was called NuKernel and was destined for Copland. Performance was said to be awesome, but the development was only completed very late, just before Copland was cancelled. Making a new kernel is NOT trivial. Mach has an advantage in working well on systems with many cores. That is where we are moving, so now woudl be a very bad time to replace it.

[Catfish_Man]

Originally Posted by P

Apple tried to make a new kernel once. It was called NuKernel and was destined for Copland. Performance was said to be awesome, but the development was only completed very late, just before Copland was cancelled. Making a new kernel is NOT trivial. Mach has an advantage in working well on systems with many cores. That is where we are moving, so now woudl be a very bad time to replace it.

Mach itself scales very well with more cores; Xnu does not, particularly, due to some locking issues in the BSD layer. Apple has been hard at work on fixing this, though.