# Jaguar = Free BSD 4.4... good or bad?



## TommyWillB (May 18, 2002)

> _from http://www.macdevcenter.com/pub/a/mac/2002/05/09/wwdc_overview.html_
> *...Jaguar will update the Unix it sits on top of to Free BSD 4.4....*



I can't keep this straight...

I know that OS X was a Mach BSD, but what is going to be different about OS X 10.2 instead being Free BSD?

Is this a small thing or a big deal?


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## chenly (May 18, 2002)

Mach is the microkernel, the base level of the operating system and the one which interacts directly with the hardware. Mach was originally developed by the computer science program at Carnigie-Melon University and was used by NeXT Computer, the company Steve Jobs founded after the 1985 spat with John Sculley, Apple's then-CEO.

BSD stands for Berkely Standard Distribution, that is, of UNIX; Darwin (and, hence, Mac OS X) use FreeBSD, a free variant of BSD (duh) as an intermediate layer between Mach and the rest of OS X.

The rest of OS X consists of the Aqua interface, AppleScript, QuickTime, Quartz (the 2D graphics engine of OS X), OpenGL (the 3D graphics engine of OS X), etc... 

SO...

BSD 4.4 is more than welcome, as long as it's completely stable, which I happen to know that it is. Apple will integrate and improve everything and wrap it into 10.2. Go Apple!


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## TommyWillB (May 18, 2002)

So when Apple builds new hardware, they wire that up at the micro-kernel level, but the BSD kernel level and everything above it stays the same... Is that right?

So I guess I should get my head to think of the microkernel as some sort of sub-kernel... or something like a hardware abstraction layer...

Thanks!


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## chenly (May 18, 2002)

No, no, you've got it, testuser. Mach *IS* a very small kernel, while the Linux kernel is comparatively large. It's a difficult concept to wrap your brain around, but you've got it. How about you, TommyWillB? Is this clicking (awful pun intended)?


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## TommyWillB (May 18, 2002)

Moof! Moof!

That's a good boy. 

I think he's got it!

Now I can't wait to see what's new in it...


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## scruffy (May 19, 2002)

I though 10.1 was already mostly based on FreeBSD 4.4...   Guess I was wrong.  Maybe 4.2 or 4.3?  Anyway, seems FreeBSD is on 4.5 now, in feature-freeze for 4.6


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## ksuther (May 19, 2002)

Oh well scruffy, maybe we'll see 4.5 in 10.3 or whatever, and by the time 10.5 rolls around, Apple will just be getting 4.6 in, and they'll be finishing up 5.0


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## scruffy (May 19, 2002)

ksuther - as you say, rather that than rushing to get the absolute latest new version in there.  Nothing wrong with 4.4, is there?


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## ksuther (May 19, 2002)

I don't quite follow you... 
I'm just saying Apple takes their time


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## strobe (May 19, 2002)

I'm really tired of trying to end this stupidity...but oh well here I go again...

Mac OS X dosn't use the Mach 3 microkernel. It uses a kernel called 'xnu' which is based on a modified version of Mach3, BSD, and a new driver architecture rolled into one gigantic 4MB binary. In other words BSD is no longer a service run on top of Mach, instead it all runs in kernel space whereby an IPC only requires a function call speeding things up (in theory anyway).

I don't see how anybody can call this a microkernel.


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## chenly (May 19, 2002)

Thank you, strobe! I was not aware that Apple had made the switch from micro- to macrokernel (then again, I haven't checked for around three years).


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