[Beowulf] s_update() missing from AFAPI ?

Andrew Piskorski atp at piskorski.com
Sat Oct 16 12:01:34 PDT 2004

The old 1997 paper by Dietz, Mattox, and Krishnamurthy, "The Aggregate
Function API: It's Not Just For PAPERS Anymore", briefly mentions that
their AFAPI library also supports, "fully coherent, polyatomic,
replicated shared memory".  It even gives a little chart showing how
many microseconds their s_update() function takes to update that
shared memory.

That sounds interesting (even given the extremely low bandwith of the
PAPERS hardware, etc.), but, no such function exists in the last
1999-12-22 AFAPI release!  s_update() just isn't in there at all.
Why?  Tim M., I know you follow the Beowulf list, so could you fill us
in a bit on what what happened there?


While I'm at it I might as well ask this too:  That same old PAPERS
papers says "UDPAPERS", using Ethernet and UDP, was implemented, but
it doesn't seem to be in the AFAPI release either.  What happened with
that?  Did it work?  As well as the custom PAPERS hardware?

If so, how?  Dirt cheap 10/100 cards and UTP cable would certainly be
a lot more convenient than custom PAPERS hardware for anyone wanting
to experiment with the AFAPI stuff, but I'm confused about what part
of the ethernet network could be magically made to act as the NAND
gate for the aggregate operations.  Did it need to use some particular
programmable ethernet switch?  Or the aggregate operations were
actually done on each of the nodes?

Andrew Piskorski <atp at piskorski.com>

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