>You could always effect your own parallel IO (e.g., use MPI sends and receives to coordinate parallel reads and writes), but >why?  It's already done in the MPI-IO implementation.

Just a moment: you're saying that i can do fwrite without any lock? OpenMPI does this?

And, what is ROMIO? Where can i find any informations?

Thanks a lot!

2008/7/23 Jeff Squyres <jsquyres@cisco.com>:
On Jul 23, 2008, at 6:35 AM, Gabriele Fatigati wrote:

>There is a whole chapter in the MPI standard about file I/O operations. I'm quite confident you will find whatever you're looking for there :)

Hi George, i know this chapter :) But i'm using MPI-1, not MPI-2. I would like to know methods for I/O with MPI-1.

Open MPI builds ROMIO by default; there's no real distinction between MPI-1 features and MPI-2 features in the Open MPI code base.

You could always effect your own parallel IO (e.g., use MPI sends and receives to coordinate parallel reads and writes), but why?  It's already done in the MPI-IO implementation.

FWIW: I do not believe that flock() is guaranteed to be safe across network filesystems such as NFS.

--
Jeff Squyres
Cisco Systems


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Gabriele Fatigati

CINECA Systems & Tecnologies Department

Supercomputing Group

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