OT: Unix or UNIX or unix

Smoot Carl-Mitchell smoot at tic.com
Thu Jun 11 15:21:22 UTC 2009

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.
Smoot Carl-Mitchell
Computer Systems and
Network Consultant
smoot at tic.com
+1 480 922 7313
cell: +1 602 421 9005

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