All, I have been trying to run an inversion process (magsen3d) that calculates a large matrix, perhaps in the order of 5-10GB. It takes about 3 days on my cluster however, it fails towards the end, when it is trying to bring in the bits and pieces calculated from the three computers that shares the load (3 rack computers, each 2 CPUs). I have attached a screenshot of the output at failure, including the command that starts the process. All output after "0 5 10 ... 95 100" are error messages of some sort or other. This problem may be with the actual application (magsen3d) or hardware on these computers and not with MPICH2, I have no idea but I will ask the programmers as well (and they may also be on this list). I have cut back on number of nodes (threads/cores) I used as there were previously errors in /var/log about out of memory. However, this time there are no messages in any of those logs on any of these three computers. If any of you could help me assess whether this is a problem with MPICH2 or something else, then that would be a huge help to me. I am running Centos on two of the computers including turner, and RH on the third. Let me know if there are any additional info you may need. Thanks, Ron