21 Aug
2001
21 Aug
'01
12:50 p.m.
Since parts have gotten faster, and since SRAMs are pretty cheap, it would
probably be fun to put a bunch of 20MHz Z80C00 (Z84C0020) types, some of which
are still out there in distribution, together with a 64K SRAM chip for each,
onto a board and let each one communicate with a "master" processor that loads
code to and processes semaphores from each one. That might provide an
interesting environment in which to fiddle with simple parallel processing.
If one could get the alleged 14MHz 65C02, it would be even easier to do with
that one, since it doesn't access memory during half its bus cycle, so a
communication path always exists between the master and slaves' memory. It's
been claimed that these 14 MHz processors, if they exist, (see
www.westerndesigncenter.com) happily run at 20 MHz under ordinary (room
temperature, etc) conditions. 20 MHz 65C02's would be WAY faster than 20 MHz
Z80's. (Now, this doesn't mean other Z80 scions, but only Z84C0020's!)
You might be surprised what a bunch of these guys can do when working on the
same tasks together. I once used 6 65C02's to process a graphics array in such
a way that 8-bit indexing was all they needed for each to paint within his own
domain. The fact that they all ran the same code, and hardware mapped each one
into its own portion of the display memory array, made for a very fast drawing
engine. The display refresh logic and master processor had to work out who was
going into memory next, but the 6502's didn't have to concern themselves with
that at all.
Dick
----- Original Message -----
From: "Master of all that Sucks" <vance(a)ikickass.org>
To: "Adrian Vickers" <avickers(a)solutionengineers.com>
Cc: <classiccmp(a)classiccmp.org>
Sent: Tuesday, August 21, 2001 1:05 PM
Subject: Re: MPP Possibility (Was: Notice)
On Tue, 21 Aug 2001, Adrian Vickers wrote:
How hot do Z80s get under normal operation? Would you be able to
overclock them using heatsinks without fans? That would simplify things a
bit.
This leads
to one mind-boggling possibility. If one etches custom boards
with eight Z80s each, and pumps all eight each clock, and one takes
several thousand of these boards, wouldn't that be a rather interesting
MPP supercomputer? Would it be more or less money than one made with,
say, IBM POWER4s, or Alphas, or StrongARMs?
Heh! I like it... The chips would be cheaper in bulk as well, and with a
bit of heatsinking it should be possible to overclock them somewhat. Mind you, even with discounts you're looking
at twenty grand just to sort
out your processor farm; and you still need the i/o logic...
Yes, but how fast a computer would you get for $20,000? Would it be
faster than other machines at that price? I don't think the I/O would be
a big deal. You could use off-the-shelf components to do it.
Still, 8000 Z80s running at 4MHz could
theoretically yield the equivalent
of 1 Z80 running at 32GHz.
That's assuming that the task you're running can be parallelized to that
degree. And plus, if you were to run each of these hypothetical 8-Z80
boards as a single CPU, you would have a 64-bit system.
Peace... Sridhar
Would Manic Miner be playable at that speed? ;)
Cheers!
Ade.
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