Newsgroups: comp.parallel.mpi
From: lusk@mcs.anl.gov (Rusty Lusk)
Subject: Re: p4 & mpich
Organization: Math and Computer Science, Argonne.
Date: 11 Dec 1995 16:58:54 GMT
Message-ID: <4aho0e$bs9@milo.mcs.anl.gov>

In article <4a4ims$19m@wonder.itc.it>, cattoni@irst.it (Roldano Cattoni) writes:
|> I am new to MPICH and I apology for my basic questions:

|> - on which architecture and structures is MPICH based?

MPICH is built on an Abstract Device Interface consisting of macros that 
are instantiated to provide the fastest available communication mechanism on
each machine.  There are currently about 20 instantiations of the device
layer.  Some of them have been supplied by vendors.

|> - what is the "p4" mechanism in MPICH? 
|> 

One of the device instantiations is for p4, a portable message-passing
system in its own right.  For parallel machines made up of networks of
machines communicating via IP (but only for such machines) MPICH uses
the p4 device, which in turn uses TCP on such networks.

p4 doesn't use daemons, which have advantages and disadvantages.

We are currently working on a new 'tcp' device, which will replace the
p4 device, and provide a foundation for MPI-2's dynamic process
management functions on workstation networks.  It is still in progress.

Hope this helps.

Rusty Lusk

