philosophical question

[Ward William E PHDN]

-----Original Message-----
From: Walter B. Ligon III [mailto:walt at parl.ces.clemson.edu]
Sent: Monday, July 17, 2000 11:10 AM
Subject: Re: philosipical question 

> A Beowulf system has the following characteristics:

> 1) designed for parallel (high-performance) computing

> 2) dedicated nodes - private network

> 3) COTS hardware

> 4) open-source system software

> It seems the question is this: is Myrinet or SCI considered COTS?  Depends
> on what COTS mean.  I've heard it as "Commercial Off-The-Shelf" and as
> "Commodity-Off-The-Shelf".  These products would fit the first definition
> and not the second.

> The original spirit of Beowulf was based on the second definition.  The
idea
> was to get the best price/performance possible from mass-produced parts.
> At the same time I don't think anyone intended to exclude innovation in
> new hardware, especially in the network.  I don't think most people today
> would exclude Myrinet or SCI as a Beowulf - but as has already been
pointed
> out, this treads on the grounds of philosophical argument - I'd rather not
> get into THAT fray!

> Walt

Walt, while I agree with what you are saying in practice, I have to
disagree... 
COTS definitely needs to be defined as COMMODITY Off the Shelf, and not
Commercial.  
I can buy  (realistically quickly) an Origin from SGI "Commercially Off the
Shelf".  
No one here is going to argue that an Origin != Beowulf.  One may argue "But
an 
Origin is also a 'Complete Turnkey' system... not a Beowulf, that is built
up 
of parts into a Cluster machine."  You would be right, in part... but one 
would be wrong.  VA-Linux sells 'Complete Turnkey' systems... plug in your 
hardware and go, and you have a Beowulf... or would one argue then that
"Part 
of the definition of a Beowulf is that it would also have to be a CLUSTER 
machine"?  ASCI has done some interesting things with Origin, SP, and
Starfire
clusters...  The last argument would be "Ah, but it doesn't use Open Source 
System software!", which of course is poppycock as well, since there are
MIPS 
ports, for example, of Linux such that you COULD run a Beowulf on a MIPS 
architectured machine... and MPI and PVM are also available for IRIX, as 
well, which is another part of the system software.

The best definition I've heard in the end is the based on the  "Duck" 
definition... "If it walks like a duck, and quacks like a duck, and acts
like 
a duck, and looks like a duck, it's a duck." i.e., "If it looks like a
Beowulf,
and works like a Beowulf, and performs like a Beowulf at Beowulf costs, it's
a Beowulf."

In the purest terms, SCI and Myrinet machines are NOT Beowulfs.... but in a
more 
"real" term, they are simply bleeding edge High Performance markers for
where 
Beowulfs are  headed, and every bit as "Wulfish" as any other FE based
design.

Bill Ward
My opinions, and I'm sticking to them ;)