Re: [tlug] A mac linux question

[Matt Doughty <mdoughty@example.com>]

On Thu, Jul 11, 2002 at 09:56:45AM +0100, Simon Cozens wrote:
> Matt Doughty:
> > IIRC 
> 
> You don't. :)
> 

Not surprising. I have heard so many conflicting reports on what exactly
the OSX kernel is that the fact, and fiction was destined to get muddled
in my always muddled mind. :)

> > It is *BSD userland grafted on to some crossbreed kernel that is 
> > using mach for all the fun low level service stuff(threads, IPC, virtually
> > memory management etc.)[1] 
> 
> It's a fairly standard BSD kernel (based on FreeBSD, I think) which handles
> its own VM, Unix and SysV IPC. Mach handles the intrakernel IPC and threading.
> 

Is there anywhere I read about this authoritatively? I would love to 
understand it better. I dug around a bit in their docs and found
this:

* Mach. Provides the fundamental abstractions and implementations of tasks, 
  threads, ports, virtual addressing, memory management, and intertask 
  communication. Mach is also the part of the operating system that manages 
  processor usage, handles scheduling, and enforces memory protection. In 
  addition it provides timing services, synchronization primitives, and a 
  messaging-centered infrastructure to the rest of the operating system.

Which is exactly the sort of thing that lead to my misconceptions of
what Mach is doing.  I guess one can always go digging into the Darwin
source, but I would like a slightly less time consuming way to get a
general understanding of how it all ties together.  

--Matt