Subject: Communication contexts

From: [email-masked] (David Walker)
Date: Fri, 15 Jan 1993 15:29:49 -0500

I thought the discussion of communication contexts at the last Dallas meeting
was lacking in focus, and I'm afraid the existing subcommittees may
not deal with this area. If there are enough people interested perhaps there
should be a separate communication context subcommittee. If you have any
strong opinions on this please let me know. Also let me know if you would
like to be on the communication context subcommittee if one is established.

On the topic of communication contexts I think (at least) 4 approaches have
been proposed.
	1) Implicit communication contexts as in MPI1 controlled by push/pop.
	2) Explicit registration as in Zipcode
	3) Explicit communication contexts should be merged with explicit
           group contexts. Since groups cannot communicate with each other
	   a new communication context can be created by creating a new group 
	   with the same members as the current group.
	4) Chuck Simmons of Oracle has suggested that communication contexts
	   are really a particular type of thread, and so can be handled
           using existing threads packages.
If you have any ideas, or are strongly for or against any of the above
approaches let mpi-comm know so we can initiate a discussion of this topic.

David Walker