Dear MPI-Forum, should we extend the MPI-I/O interfaces for directory operations? Especially a "mkdir -p" equivalent could be useful. In many scientific apps that create output at scale, an output structure needs to be created on demand. One can of course decide to do so with e.g. Linux `mkdir` but this can be tricky: If all ranks do it, one will race the others and it's unnecessary expensive in terms of operations. If a "root" rank does it, there is no guarantee that e.g. a MPI_Barrier which syncs the "MPI-World" will also cause the "filesystem-world" to be up-to-date. For example a mkdir on a slow NFS local node has bot yet propagated to the other compute nodes. Comments, feedback and overlooked already existing solutions welcome! Best regards, Axel Huebl -- Axel Huebl Phone: +49 351 260 3582 Institute of Radiation Physics http://www.hzdr.de/crp Helmholtz-Zentrum Dresden - Rossendorf (HZDR) Bautzner Landstr. 400 | 01328 Dresden | Germany Board of Directors: Prof. Dr. Dr. h. c. Roland Sauerbrey, Dr. Ulrich Breuer Company Registration Number VR 1693, Amtsgericht Dresden