I'm removing the question MPI_MODE_RDONLY, MPI_MODE_RDWR, MPI_MODE_WRONLY Is it an error to specify more than one of these? from the errata page, because MPI-2.0, Sect. 9.2.1, page 213 lines 3-4 read: Exactly one of MPI MODE RDONLY, MPI MODE RDWR, or MPI MODE WRONLY, must be specified. This means, the question is already fully answered. And there seems not to be any mail discussion on this topic. Was there any mail (not on the Forum reflector) asking this? If yes, this mail might be forwarded to the questioner. Best regards Rolf Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner_at_[hidden] High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner Nobelstr. 19, D-70550 Stuttgart, Germany . (Office: Allmandring 30)