Feedback from the readers of Linux Magazine
One reader takes issue with Donald Becker’s assessment of MPI.
Sunday, January 15th, 2006
Reality Check
As I read Donald Becker’s article “Beyond MPI”[ published in the November 2005 issue of
Linux Magazine, available online at
http://www.linux-mag.com/2005-11/beyond.html], I was horrified to see such a luminary present so many errors, inaccuracies, and misleading statements. Here’s a list of problems with the article:
1.MPI is not static. MPI has had dynamic API support since 1996;
LAM/MPI started supporting it in 1998; and support in other MPI implementations started showing up at around the same time. A column of mine in
ClusterWorld Magazine (
http://www.clusterworld.com/) made the assertion that MPI could be used for distributed programming using its
CONNECT/ACCEPT primitives. Becker’s statement equating the size of a cluster with
MPI_Comm_size(MPI_COMM_WORLD) demonstrates a fundamental misunderstanding (or deliberate misrepresentation).
2.Implying that MPI cannot handle versioning is silly. In general, if you run multiple versions of network communication protocols, you’re going to run into problems, unless the applications are version aware and are able to fall back to older protocols upon demand. MPI could certainly do this, but no one has[ yet] asked for the feature. Versioning — the popularly- and aptly-named “DLL Hell” problem — is by no means unique to MPI, and implying otherwise is a misrepresentation.
