[geeks] q: good source for leather book bag?

[gsm at mendelson.com]

On Wed, Jun 03, 2009 at 02:26:48PM -0400, der Mouse wrote:
>It is not.  BSD systems use monolithic kernels; Darwin is a microkernel
>(Mach, I think) with a Unixy (and mostly BSDish) layer dropped on top.
>
>Unless you're identifying the system with the userland, ignoring the
>kernel, which strikes me as (a) nonstandard and (b) broken.

According to the Wikipedia:

http://en.wikipedia.org/wiki/Darwin_BSD


Kernel

   Darwin is built around XNU, a hybrid kernel that combines the Mach 3
   microkernel, various elements of BSD (including the process model,
   network stack, and virtual file system), and an object-oriented
   device driver API called I/O Kit.

   Some of the benefits of this choice of kernel are the Mach-O binary
   format, which allows a single executable file (including the kernel
   itself) to support multiple CPU architectures, and the mature support
   for symmetric multiprocessing in Mach. The hybrid kernel design
   compromises between the flexibility of a microkernel and the performance
   of a monolithic kernel.


You can interpet it as you want, to me it says that Darwin is an improved
BSD kernel.

At one time BSD was a set of patches to the AT&T UNIX kernel, not a
stand alone operating system. The current crop of BSD's such as Open and Net
trace their ancestry back to a hack to remove all of the AT&T code from 
the i386 implementation, and have no code in common with the UNIX
it was built on.

I actually met someone who had been part of the team to compare the AT&T
source code line by line with the open source BSD to verify there was not
one line of common code. 

SunOS I believe was different as they had a license to distribute the complete
product from both AT&T and UCB. As far as I remember it was the only one.

That system has been unenhanced, except for Y2k patches for what, 14 years? 

Geoff.
-- 
Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM