Anh -- This may have already occurred to you, but I just had a thought: we should ensure that the design of MPIR-2 allows both tools/debuggers and MPI implementations to support both versions simultaneously. E.g., Open MPI will need to support both MPIR-1 and MPIR-2 until all the debuggers support MPIR-2. Likewise, debugger X will want to support both MPIR-1 and MPIR-2 until all MPI implementations support MPIR-2. Meaning: we need to make sure that if any global symbols are shared between MPIR-1 and -2, they must be used either in identical ways, or will only be used / examined / etc. after the the version of MPIR has been negotiated between the MPI implementation and the tool. -- Jeff Squyres [email protected] For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/