Max OS X and BSD

John Von Essen john at
Thu Apr 8 20:53:24 PDT 2004

I need to get something cleared up in my head because it is driving me 
nuts. It has to do with the relationship between Mac OS X and BSD.

For starters, I am an "old" NeXT user. I used NeXTSTEP 3.x and OPENSTEP 
4.2. I remember back in 97, Apple acquired NeXT software and thus 
acquired the OPENSTEP 4.2 operating system. At the time I was running 
OPENSTEP 4.2 (along with the ill-fated WebObjects) on a Pentium II box, 
and running NEXTSTEP 3.3 User on a NeXTStation Mono Slab. Around that 
time, Apple started work on rhapsody - their next generation OS. I was 
under the assumption that rhapsody (and later darwin) was basically an 
OPENSTEP derivative with a brand new graphics layer. Its obvious to 
anybody who uses OS X currently, and who used to use OPENSTEP 4.2. In 
OS X, the app NetInfo is strikingly similar to the NetInfo app in 
NEXTSTEP/OPENSTEP. A ps -ax lists a whole bunch of processes that are 
also strikingly similar between the two. The there are things like 
WebObject which came from OPENSTEP 4.2, Objective-C framework which was 
present back in NEXTSTEP versions.

I was under the impression that OS X was a derivative of OPENSTEP - 
which means from a kernel standpoint it is NOT BSD and NOT System V, 
rather it is a MACH kernel (which sort of is a BSD kernel derivative). 
Apple scraped the graphics layer and made their own. And this is where 
the BSD connection comes in, Apple scraped OPENSTEP's TCP/IP and opted 
to use the one from FreeBSD - which is the best!

The problem is I hear things from people, and I read things from 
prominent sources, that completely make no sense. Things like:

OS X is FreeBSD
OS X is BSD Unix
Apple uses the FreeBSD kernel

And today I got a security email from WatchGuard (the crapy firewall 
people) with the statement:

"With OS X, Apple changed the core of its operating system to a version 
Unix known as BSD."

Then colleges of mine read that, and they come to me and say, "Hey, did 
ya hear? Apple uses FreeBSD"

Its driving me nuts, when are people going to get things straight? Or 
am I completely off base here?!


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