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Mips On VESA

To: riscy@pyramid.com (Mips 3000)
Subject: Mips On VESA
From: Bill Broadley <broadley@neurocog.lrdc.pitt.edu>
Date: Mon, 26 Jul 1993 15:45:59 -0500 (EDT)
Reply-to: riscy@pyramid.com
Sender: owner-riscy@pyramid.com
I'm not against a reasonably priced MIPS motherboard.  So far the solutions 
seem to be in the > $800 range for a machine with a tiny cache and dumb video.

If it can be built with the available talent so that we can built it and
it works, great!  I'll buy one.

On the otherhand design complexity/development costs could be a problem.
How many board revisions are typical for a board like this?  What's the 
possiblility that a 40 Mhz cpu+ram+isa+ethernet+video+serial is going to
work the first time?  How much does it cost per redesign?

I was just suggesting a VESA card with enough sockets/simms for up to 1 MB
cache.  That's it, no RAM on board.  I'd guess the cost would be around $100
for the board, + cache chips + cpu.  This would give a wide range of 
price/performance options, after all VESA is basically a memory bus.

I don't see any performance problems with a mips chip in a vesa slot, It seems 
the easiest to design, and could offer a large range of price/performace 
alternatives.   If you see any performance problems please let me know.

I'd probably buy a 486 25 sx motherboard for $180, add my video card,
add my serial ports, and my ide controller+IDE drive.  Then buy the mips VESA 
card ($100)+512k cache (what $200?)+cpu.

As a side effect the VESA card could probably sell in higher numbers becuase
it's cheaper and it's less of a risk for those that are scared that the linux 
port won't happen, minimum cost of entry would be cpu+$100.  I'd imagine a 
FAST cpu on a VESA card that runs linux could become quite popular, allowing 
us to spread the development costs around. 

So for $180(486sx mtb)+$100(mips board)+$200(cache)+Mips cpu(?) I'd spend $480+
cpu for a system that has 512k cache, 100 MB/s cache <-> ram, slow video, 800k 
/sec bandwidth on my $298 340 MB ide drive.  I would probably buy a S3-805 for 
$150 or so to improve the video speed.

As far as I can tell none of this hurts workstation like performance.  For
those that can't live with 800k/sec get a better controller.

The proposed configurations so far have had very small caches, and dumb frame 
buffers.  I'd prefer to pay $150 for an 1 MB s3-805 then $100 or so for
a on board dumb frame buffer.  The load on the cpu and memory bus would be 
much less.  Will the dumb frame buffer handle the timings for my interlaced 
color display?

So in summary give me a do it all motherboard that I can afford and I'll be
a happy camper.  If not give me a cache+cpu on a VESA card and I'll still
have a fast workstation like machine.

I'm not a EE/hardware person so I'm welcome to corrections but it seems
that a VESA card would be more likely to be produced then a FULL motherboard.

BTW I believe there are now mips 4k, and power pc VESA cards available now.
Bill                                    1st>    Broadley@neurocog.lrdc.pitt.edu
Broadley@schneider3.lrdc.pitt.edu <2nd  3rd>                 Broadley+@pitt.edu
Linux is great.         Bike to live, live to bike.                      PGP-ok

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