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From: ken@dali.gatech.edu (Ken Seefried iii)
Newsgroups: comp.unix.amiga,comp.sys.amiga.misc
Subject: Re: Adding Symmetric Multiprocessing to Amiga UNIX.
Message-ID: <20668@hydra.gatech.EDU>
Date: 29 Jan 91 17:41:45 GMT
References: <1991Jan29.024542.1@ccvax.iastate.edu>
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Reply-To: ken@dali.gatech.edu (Ken Seefried iii)
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In article <1991Jan29.024542.1@ccvax.iastate.edu> taab5@ccvax.iastate.edu (Marc Barrett) writes:
>
>   It has been discussed before (especially in comp.sys.amiga.hardware)
>that, when a CPU card (such as a 68040 card) is added to the Amiga 3000,
>the 68030 on the motherboard remains available as a coprocessor.  
>Unfortunately, neither AmigaOS nor UNIX SysVR4 support multiprocessing,
>so although the 68030 remains available hardware-wise, it is unavailable
>for use because of the system software.

Two problems with symmetric multiprocessing:

The 68030 has something like a quarter of the horsepower the '040 has,
making response time in an SM system erratic at best.  

Second, you need hardware support to do real SM, for things like cache
coherency and resource locking (yes, I *know* I'm glossing over a lot
of things...I'm tired).  Does this little accellerator board support,
say, shared memory between the '040 and the '030?

Now, as long as the '040 and the '030 could interrupt one another, you
could use the '030 as an I/O front end of some sort.  That might make
sense...

--
	ken seefried iii	"A sneer, a snarl, a whip that
	ken@dali.cc.gatech.edu	 stings...these are a few of
				 my favorite things..."