[CPMD-list] Upon compilation of cpmd2cube...

[Axel Kohlmeyer]

On Thu, 27 May 2004 kohsj at ihpc.a-star.edu.sg wrote:

AK> Thanks Dr. Axel.  I should've mentioned that the previous versions of "Makefile" that you attached did not produce the ".nfsXXXXX" files, only the latest one did.
AK> 
AK> Any clue as to why this "Makefile" gave those files?

adrian,

this has _nothing_ to do with the makefile itself. 
most likely you have accessed (and overwriteen) the file 
with two editor sessions simultaneously.

axel.

AK> 
AK> Cheers,
AK> Adrian.
AK> 
AK> 
AK> 
AK> ----- Original Message -----
AK> From: Axel Kohlmeyer <axel.kohlmeyer at theochem.ruhr-uni-bochum.de>
AK> Date: Thursday, May 27, 2004 4:22 pm
AK> Subject: Re: [CPMD-list] Upon compilation of cpmd2cube...
AK> 
AK>  
AK>  On Thu, 27 May 2004 kohsj at ihpc.a-star.edu.sg wrote:
AK>  
AK>  AK> Dear Dr. Axel,
AK>  AK> 
AK>  
AK>  AK> Is there any way that one can remove the .nfsXXXXX files, and
AK>  AK> subsequently, the "cpmd2cube-v0.1.1" folder?
AK>  
AK>  the explanation should have made it clear, that you simply
AK>  have to terminate _all_ processes accessing files in that directory,
AK>  including editors, file viewers, file managers, directory browsers etc.
AK>  
AK>  axel.
AK>  
AK>  AK> 
AK>  AK> Thanks again!
AK>  AK> 
AK>  AK> 
AK>  AK> 
AK>  AK> AK> My IT man suggested that it could probably be:
AK>  AK>  AK> 
AK>  AK>  AK> 
AK>  AK>  AK> "Since you are the one who create the folder, you shall 
AK>  have the 
AK>  AK>  right to
AK>  AK>  AK> remove anything in the folder. However, you claim that you 
AK>  AK>  delete the
AK>  AK>  AK> file and it come back again. This is mostly likely due to 
AK>  your 
AK>  AK>  program.AK> You may have write a program and this program may 
AK>  need 
AK>  AK>  to write
AK>  AK>  AK> something in this folder everytime it is running and 
AK>  therefore 
AK>  AK>  the file
AK>  AK>  AK> come back after you delete it. I just make a guess and I do 
AK>  not 
AK>  AK>  have any
AK>  AK>  AK> evidence to support my point. Hope that clear your doubt."
AK>  AK>  
AK>  AK>  well, this is close to the explanation. the reason for the 
AK>  .nfsXXXXX 
AK>  AK>  filesis 'feature' of NFS in order to emulate posix style file 
AK>  access 
AK>  AK>  semantics.to explain: if you delete a file on a posix/unix 
AK>  machine, 
AK>  AK>  the file is
AK>  AK>  initially only removed from the directory listing but not 
AK>  deleted if 
AK>  AK>  thereis still a process, that has an open file descriptor 
AK>  pointing 
AK>  AK>  to that
AK>  AK>  file. only if the last process accessing the file has ended, 
AK>  that 
AK>  AK>  file is
AK>  AK>  really deleted. this is btw a very convenient way of creating 
AK>  AK>  'invisible'scratch files, that get automatically deleted, when 
AK>  the 
AK>  AK>  process terminates
AK>  AK>  or dies (you open(2)/fopen(3) a file with a unique name for 
AK>  writing 
AK>  AK>  and 
AK>  AK>  immediately unlink(2) it). back to the .nfsXXXX file: the NFS 
AK>  AK>  filesystem,however is basically 'stateless', i.e. the 
AK>  connection to 
AK>  AK>  the NFS server 
AK>  AK>  can be interrupted any time and later reconnected (in some 
AK>  cases it 
AK>  AK>  can 
AK>  AK>  even survive an intermediate reboot with replacing the hardware 
AK>  and 
AK>  AK>  resizing the filesystem). so to implement the 'file-stays-even-
AK>  if-
AK>  AK>  deleted'semantics, the nfs server daemon acts as a proxy for 
AK>  the 
AK>  AK>  processes 
AK>  AK>  accessing the file, but to make this work even in case of a 
AK>  reboot, the
AK>  AK>  .nfsXXXX files are created. the XXXXX is an hash, that allows 
AK>  the 
AK>  AK>  serverto detect the process needing to access the 'file with no 
AK>  name'.AK>  most frequently this happens if you open a file in an 
AK>  editor, that
AK>  AK>  keeps an open file descriptor to the file it opens (or to the 
AK>  AK>  associated backup/undo file).
AK>  AK>  
AK>  AK>  
AK>  AK>  
AK>  AK>  axel.
AK>  AK> 
AK>  
AK>  -- 
AK>  
AK>  
AK>  =======================================================================
AK>  Dr. Axel Kohlmeyer                        e-mail: axel.kohlmeyer at rub.de
AK>  Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
AK>  Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
AK>  D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
AK>  =======================================================================
AK>  
AK>  
AK>  
AK> 

-- 


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Dr. Axel Kohlmeyer                        e-mail: axel.kohlmeyer at rub.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================