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Subject: Re: [OMPI users] Parallel I/O with MPI-1
From: Gabriele Fatigati (g.fatigati_at_[hidden])
Date: 2008-07-23 08:24:03


>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_at_[hidden]>:

> 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
Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
www.cineca.it Tel: +39 051 6171722
g.fatigati_at_[hidden]