[gmx-users] Why does the -append option exist?

[Jussi Lehtola]

On Fri, 3 Jun 2011 18:26:17 -0400
Dimitar Pachov <dpachov at brandeis.edu> wrote:
> If one uses that option and the run is restarted and is again
> restarted before reaching the point of attempting to write a file,
> then things are lost, and most importantly, the most important piece
> of data, that being the trajectory file, could be completely lost! I
> don't know the code behind the checkpointing & appending, but I can
> see how easy one can overwrite 100ns trajectories, for example, and
> "obtain" the same trajectories of size .... 0.

So you are referring to the case where you have multiple, independent
processes all using the same trajectory file. Yes, this will probably
lead to problems, unless the trajectory file is somehow locked.

So: does GROMACS lock the trajectory files it operates upon? If not, it
should.
-- 
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Mr. Jussi Lehtola, M. Sc.         Doctoral Student
jussi.lehtola at helsinki.fi         Department of Physics
http://www.helsinki.fi/~jzlehtol  University of Helsinki
Office phone: +358 9 191 50 632   Finland
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Jussi Lehtola, FM                 Tohtorikoulutettava
jussi.lehtola at helsinki.fi         Fysiikan laitos
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