OT: Unix or UNIX or unix

Christopher Chan christopher.chan at bradbury.edu.hk
Fri Jun 12 03:18:14 UTC 2009

Smoot Carl-Mitchell wrote:
> On Thu, 2009-06-11 at 22:18 +0800, Chan Chung Hang Christopher wrote:
>>> Except that all Unixes shared a common code base somewhere in the past,
>> I wonder how much of Mac OS X does come from that common code base.
> OSX is base on FreeBSD.  The BSD codebase was originally from AT&T
> System 7.  There was a virtual memory port to the VAX in the late 1970s.
> >From that base the BSD folks wrote an operating system for the VAX with
> network support under a contract from DARPA.  That is the basis of the
> TCP/IP stack and is one reason why that code was released under the BSD
> license. It was funded with taxpayer dollars.  Most Unices licensed
> originally from AT&T used the BSD stack.  I suspect there is still BSD
> code in most of the proprietary Unices to this day.  Check out their
> copyright disclaimers.  If the Regents of the University of California
> is mentioned, then the OS has BSD code in it.
> Later the BSD crew rewrote the entire operating system and freed it form
> the original AT&T license.  AT&T sued, claiming this was not the case,
> but the suit was settled out of court.  The codebase in FreeBSD and
> OpenBSD are offshoots of that settlement and are free of the original
> Unix licensing restrictions.
> I am sure I have missed a few details here and there, but the bottom
> line is Apple uses FreeBSD as its base for MacOSX because it gives them
> more flexibility to add stuff to the OS without the restrictions imposed
> by the GPL.  Personally, I think the GPL restrictions are quite
> reasonable and we have seen viable business models (e.g. RedHat,
> Canonical, et al) based on that underlying license.
I see others saying that Mac OS X has bits from FreeBSD and NetBSD. How 
much of Mac OS X comes from those two sources would be really 
interesting to compare. In any case, you can now be a UNIX if you have 
the proper interfaces regardless of whether the code has any link with 
the original AT&T codebase.

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