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At 10:52 AM 5/23/2007, Peter St. John wrote:<br>
<blockquote type=cite class=cite cite="">But oh and Jim if you recall any
papers about this I could read that would be "Jim"
Dandy.</blockquote><br>
I was working off memory, and the iPSC/1 and iPSC/2 manuals I have in my
office as a historical artifact. <br><br>
I seem to recall that if you google hypercube and intel, you'll turn up
some of the papers that were written early on. The guys who started
with the hypercube interconnect were at CalTech, as I recall, and spun
off to form a supercomputer company embodying that, which Intel also
adopted.<br><br>
<blockquote type=cite class=cite cite="">Peter<br><br>
<br>
On 5/23/07, <b>Jim Lux</b>
<<a href="mailto:James.P.Lux@jpl.nasa.gov">James.P.Lux@jpl.nasa.gov</a>
> wrote: <br>
<dl>
<dd>At 09:19 AM 5/22/2007, Peter St. John wrote:<br>
<blockquote type=cite class=cite cite="">
<dd>A hypercube
(<a href="http://en.wikipedia.org/wiki/Hypercube" eudora="autourl">
</a><a href="http://en.wikipedia.org/wiki/Hypercube" eudora="autourl">
http://en.wikipedia.org/wiki/Hypercube</a>) also gets you exponential
space; the max hops is the dimension (3 for a 3-dimensional cube) and the
number of nodes is exp(base 2) of the dimension (8 vertices on a cube).
To do a tesseract (4-cube), which looks like two cubes nested, you'd need
4 ports per node, 16 nodes, 32 cables, max hop 4. I've poked around and
don't see a great 4 ports per node solution; I like the suggestion of
putting a router on a motherboard. </blockquote><br>
<dd>Mind you, this is what Intel started with on their iPSC/1 and iPSC/2
computers. The early ones had multiple NICs in the nodes, then,
later, they had a 8 port (I think) router in each node.<br><br>
<dd>It's not clear that this saves anything over a simpler architecture
(e.g. external switch with lots of ports in a crossbar) unless you can do
circuit switched routing (so you don't have a one packet delay in the
switch) AND your algorithm can take advantage of it. I spent quite some
time in the late 80s trying to figure out clever ways to take advantage
of a hypercube topology for a modeling application.. I'm sure there
are algorithms which are a natural fit, but the ones I was using weren't.
<br><br>
<br>
<dd>James Lux, P.E.<br>
<dd>Spacecraft Radio Frequency Subsystems Group<br>
<dd>Flight Communications Systems Section<br>
<dd>Jet Propulsion Laboratory, Mail Stop 161-213<br>
<dd>4800 Oak Grove Drive<br>
<dd>Pasadena CA 91109<br>
<dd>tel: (818)354-2075 <br>
<dd>fax: (818)393-6875<br><br>
</dl></blockquote>
<x-sigsep><p></x-sigsep>
James Lux, P.E.<br>
Spacecraft Radio Frequency Subsystems Group<br>
Flight Communications Systems Section<br>
Jet Propulsion Laboratory, Mail Stop 161-213<br>
4800 Oak Grove Drive<br>
Pasadena CA 91109<br>
tel: (818)354-2075<br>
fax: (818)393-6875
!DSPAM:46549197244853022792082!
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