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Release notes for LAM LAMRV
============================

This file contains the release notes for LAM/MPI version LAMRV.
Here's a brief table of contents:

     * Installation instructions
     * Supported systems
     * New feature overview
     * IMPI functionality

Installation instructions
-------------------------

Please see the installation guide for instructions on installing LAM
LAMRV in the INSTALL-6.4 file.


Supported systems
-----------------

When compiled with the IMPI extensions, LAM LAMRV has been tested on 
the following systems:
 
        Solaris 2.7
        IRIX 6.4, 6.5
        AIX 4.1.4, 4.2.1
        Linux 2.2.16
 
When compiled without the IMPI extensions, the list of supported systems
is the same as for the LAM 6.5 series; see the RELEASE_NOTES file.

Since this is still "alpha" level software, we request that you also
download the latest stable "lamtest" package from the LAM/MPI web site
and run it on your system. If any errors are encountered, please send
us all the output (see the README file in that package).

The LAM Team would greatly appreciate your time and effort in helping
to verify LAM/MPI on a wide variety of systems. 


New feature overview
--------------------

     LAM 6.4

     * The Interoperable Message Passing Interface (IMPI) is a
       standardized protocol that enables different MPI
       implementations to communicate with each other. This allows
       users to run jobs that utilize different hardware, but still
       use the vendor-tuned MPI implementation on each machine. This
       would be helpful in situations where the job is too large to
       fit in one system, or when different portions of code are
       better suited for different MPI implementations.  

     * IMPI defines only the protocols necessary between MPI
       implementations; vendors may still use their own
       high-performance protocols within their own implementations.

     * Some new terms that are used throughout the LAM / IMPI
       documentation include: IMPI clients, IMPI hosts, IMPI
       processes, and the IMPI server. See the IMPI section of the the
       LAM FAQ for definitions of these terms at
       http://www.lam-mpi.org/faq/.

     * For more information about IMPI and the IMPI Standard, see the
       main IMPI web site at http://impi.nist.gov/.

The RELEASE_NOTES file still contains all the pertinent information
about the capabilties of LAM LAMRV. The only extensions from the LAM
6.5 series were the addition of support for IMPI. As such, all LAM 6.5
series documentation applies to LAM 6.4 as well.


IMPI functionality
------------------

Note that the IMPI standard only applies to MPI-1 functionality.
Using non-local MPI-2 functions on communicators with ranks that live
on another MPI implementation will result in undefined behavior (read:
kaboom).  For example, MPI_COMM_SPAWN will certainly fail, but
MPI_COMM_SET_NAME works fine.

LAM currently implements a subset of the IMPI functionality:

- startup and shutdown
- all point-to-point sendings and receiving
- some of the data-passing collectives:
  MPI_ALLREDUCE, MPI_BARRIER, MPI_BCAST, MPI_REDUCE

LAM does not implement the following on communicators with ranks that
live on another MPI implementation:

- MPI_PROBE and MPI_IPROBE
- MPI_CANCEL
- all data-passing collectives that are not listed above
- all communicator constructor/destructor collectives (e.g.,
  MPI_COMM_SPLIT, etc.)