[mpich-discuss] underlying POSIX calls for MPI_File_read_all and MPI_File_write_all

[Rob Latham]

On Mon, Aug 02, 2010 at 01:06:06PM -0400, shankha wrote:
> Hi,
> Will it be correct to assume that all the ROMIO read write calls
> internally call POSIX read , write in some way or the other.
> I could figure out that MPI_File_write_all calls write by trapping
> MPI_File_write_all. But couldn't figure out the underlying posix call
> for MPI_File_read_all.

in addition to what RobR said, there are at least the following
counter-examples for ROMIO:

- ad_pvfs2 (calls PVFS "system interface", not posix)
- ad_pvfs  (old pvfs v1; makes calls to 'libpvfs' API)
- ad_gridftp (makes gridftp calls, not posix)
- ad_zoidfs (speaks an experimental I/O forwarding language)

==rob

-- 
Rob Latham
Mathematics and Computer Science Division
Argonne National Lab, IL USA