[Sussex] LINUX takes on XServe

[Steve Dobson]

Tony

On 30 October 2002 at 00:28 Tony Dart wrote:
> Quote from Apples UNIX Porting Guide: 
>
> Although Mac OS X must credit BSD for most of the underlying
> levels of the operating system, Mac OS X also owes a major
> debt to Mach. The kernel is heavily influenced in its design
> philosophy by Carnegie Mellon's Mach project. The kernel is
> not a pure microkernel implementation though since the address
> space is shared with BSD processes. 
>
> end of quote. 

How can you only be part microkernel?  Either it is a microkernel
or it isn't!  It's like saying she is not a pure woman.  If, and I will
say at the moment that I know nothing of the kernel architecture of
Max X, has taken much of its "underlying levels of the [BSD]
operating system" then this a macrokernel.

I will state here and now that "A message queue API does not a micro-
kernel make".

If they have implemented the kernel API as a (set) of message queues
then this does not, IMO, make it a microkernel.  If the messages are
processed in kernel land then this IS A MACROKERNEL.

I can see some advantages to using the message queue system.  It 
guarantees the order in which system calls are executed (at least at
the subsystem level).  The POSIX API do not.

Steve