[MPICH] Limitations of MPI I/O (romio) on ntfs

[David Ashton]

James Perrin,

The flags to MPI_File_open are not correctly implemented under NTFS.  This
is a known bug that we have not fixed in the current release.

-David Ashton

-----Original Message-----
From: owner-mpich-discuss at mcs.anl.gov
[mailto:owner-mpich-discuss at mcs.anl.gov] On Behalf Of James S Perrin
Sent: Monday, June 27, 2005 7:24 AM
To: mpich-discuss at mcs.anl.gov
Subject: [MPICH] Limitations of MPI I/O (romio) on ntfs

Hi,
	I'm using mpich2 (previously mpich 1.2.5) on windows with ntfs, just
one of a 
number of platforms my applications needs to support.

	There is very little documentation on what are the limitations using
ntfs and 
what I found are through trial and error. I just want to confirm what I've
found 
or learn if there are solutions.

1. Only one process can access a file for reading. This is an annoying
problem 
as we/users have dual cpu machines. I can understand writing being
restricted to 
a single process by not reading. Is there some hint that I should be using?

2. This seems like a bug, if my file is set to read_only and even though I'm

opening it using MPI_MODE_RDONLY the file fails to open.

3. If I share a folder across a cluster (and use mpichs shared folder to
drive 
mapping) should I be able to read a file on multiple nodes (and multiple 
processes per node if 1. has a solution)?

Regards
James
	
PS Since the list server told me that the romio-users is non-existent I
guess 
this is where I should post on the subject.

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James S. Perrin,                   | email: james.perrin at manchester.ac.uk
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Manchester, England. M13 9PL.      | fax: +44 161 275 6800/6040
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"The test of intellect is the refusal to belabour the obvious" -Alfred
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