Oscar Levi said ...
> 
> On Sun, May 30, 1999 at 10:39:24PM +0100, Alan Cox wrote:
> > > The quintessential microkernel operating system is Mach.  It is based
> > > on passing messages between independent services.  The memory
> > 
> > Please don't use Mach as an example. Mach is a research tool, it is very
> > big, it nowdays uses the same address space for the kernel too.
> 
> Oh no.  I'm not a Mach fan.
> 
> Since the original question was about the nature of microkernels, Mach
> is a well-known example from a design standpoint.  Amiga's success is
> hard to measure since the product failed commercially, albeit in part
> by Microsoft's shady maneuverings.  Mach lives in the NeXT.  Another

Actually, the Amiga's downfall was due to the dunderheads at Commodore,
more that anything that Microsoft might have done.  They squandered the
money and then shafted the people who wanted to take the
product/technology and do something worth while. 

The Amiga still exists today (Amiga International) as well as a few
companies who have bought parts of the technology and will most likely
use it for TV-set top boxes or imbedded video controller devices.
Today's Amiga, however, is PowerPC based and almost nothing like the
original Amigas (which is sad). 

The Amiga's OS was very compact and extremely modular.  It's ashame the
code was never made Open Source as many people could benefit from its
elegent design and implementation.

> commercial product using message-passing microkernel is called Chorus,
> produced by a French concern.  And, there's QNX as you mentioned.  NT
> would not be characterized as a message passing system, nor as a
> microkernel by any discerning designer.

Actually, NT's *design* was very much based on a microkernel design (with
components of VMS injected into it for good measure).  Sadly, due to
practical constraints, the *implementation* deviated from the design.

-- 
Peter A. Castro (doctor@fruitbat.org) or (pcastro@us.oracle.com)

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