Dell GNU/Linux survey

[Micah DesJardins]

Lynn Newton wrote:
>> Isn't the Mac OS just a fancy gui sitting on top of BSD?
Darrin Chandler wrote:
>Apple used *significant* parts of FreeBSD for OS X. They made
>modifications, and added tons of stuff to make it Mac-like. So the short
>answer is "yes."

I would argue a more correct answer would be "sort of"

The Mac OS X kernel (known as XNU) has several distinct parts. In it
is a variant of the FreeBSD monolithic kernel, the Mach microkernel
and a driver interface known as I/O Kit.  Significant amounts of code
is an understatement.  BSD is nearly everywhere underneath Mac OS X,
but to paraphrase Spock, "It's not BSD as we know it Captain."

A lot of modification has been done to make these disparate pieces
hang together, but underneath it's still -at the very least- BSD-style
code and much of it is indeed "the same" as the FreeBSD 5 code base it
branched from.  From a userland perspective, if you treat it like BSD,
you're generally alright minus a few gotchas.  From a programming
perspective it's a very different beast.  So I suppose in the end, how
it looks is dependent on where you are standing and what portion of
the beast you are looking at.

If anyone is interested in the full story, I recommend the book _Mac
OS X Internals - A Systems Approach_ by Amit Singh.

Micah DesJardins