Dear all, A release candidate for the next release of MPICH2 (1.0.6) is available from ftp://ftp.mcs.anl.gov/pub/mpi/mpich2-1.0.6-rc1.tar.gz. Please try it out if you like and let us know if you encounter any problems. If all is well, we plan to release 1.0.6 in a few days. Regards, The MPICH2 Team Main changes in 1.0.6 - Updates to the ch3:nemesis channel including preliminary support for thread safety. - Preliminary support for dynamic loading of ch3 channels (sock, ssm, shm). - Singleton init now works with the MPD process manager. - Fixes in MPD related to MPI-2 connect-accept. - Improved support for MPI-2 generalized requests that allows true nonblocking I/O in ROMIO. - MPE changes: * Enabled thread-safe MPI logging through global mutex. * Enhanced Jumpshot to be more thread friendly + added simple statistics in the Legend windows. * Added backtrace support to MPE on Solaris and glibc based systems, e.g. Linux. This improves the output error message from the Collective/Datatype checking library. * Fixed the CLOG2 format so it can be used in serial (non-MPI) logging. - Performance improvements for derived datatypes (including packing and communication) through in-built loop-unrolling and buffer alignment. - Performance improvements for MPI_Gather when non-power-of-two processes are used, and when a non-zero ranked root is performing the gather. - MPI_Comm_create works for intercommunicators. - Enabled -O2 and equivalent compiler optimizations for supported compilers by default. - Many other bug fixes and code cleanup. A full list of change comments from the CVS commits is available at www.mcs.anl.gov/mpi/mpich2/mpich2_1_0_6changes.htm .