Looking for Portable MPI I/O Implementation?

rikt writes "I am trying to implement MPI I/O for our CFD product. I am facing a problem with the portability of the generated data files. MPI2 interface describes a way to achieve this either by using 'external32' or user defined data representations. The problem is that ROMIO, the most widely available MPI I/O implementation, has not implemented support for any data representation other than 'native'. Do you know of any MPI I/O implementation that supports this, and is available on various platforms? I know IBM and Sun supports this, but I am looking for a solution on Linux and Windows (both 32 & 64 bit) as well."