XML again

A.Buteau buteau at llb.saclay.cea.fr
Wed Jan 9 08:18:45 GMT 2002

Mark Koennecke wrote: 

> Currently there are no plans for the development of a separate NeXus-API 
>   for XML. You are the first one lobbying for this. 

I think that the underlying file format of Nexus files is a matter independant 
of the API . We can imagine that without changing the API but just by setting a 
flag,the NeXus library write the file in XML or HDF format. 

XML may be the "killer application" we were looking at (remember the
workshop at the PSI) because, for many experiments with a low volume of data 
(like triple axis, diffractometers with few detectors), it is really difficult 
to convince scientists to adopt a binary format which is by many way difficult 
to work with (for instance to get a simple plot with Excel or Kaleidagraph). 
I remember that people of the FRM-II reactor told me that some work had already 
be done on this subject. Is it true ? Anyone knows more ?  

>   If you use the new hdf-5 version of the API you obtain essentially hdf-5 
>   files. These can be converted with a standard utility coming with the 
>   hdf-5 distribution into XML-files. 

The need to avoid these conversion routines was one of the major goal of NeXus, 
so I think it must be avoided at any costs !!. 

>  - a cron job triggers a progam any 24 hours which scans for new files
>     and extracts interesting information (user, title, etc.) from new
>     files and writes this information into a mySQL database. 

Did you write your scanning program with a scripting langage like perl or 
python ? Is there a way to read NeXus files directly from a python or perl  
script ? 

Ps: About NeXus WEb site 
- the Nexus web site says nothing about HDF5 . Is it normal ? Is there any 
place telling more about that 
- the home page of Nexus (http://www.neutron.anl.gov/nexus/)
is not the same that the mirror page in Europe (http://lns00.psi.ch/NeXus/ 
which still present the NeXus'2001 workshop, March 20-21, 2001, at PSI. 
The mirroring mechanism seems to be broken
- Following the link to the mailing list archive, it appears that the last 
message on the list is from August 2001. Something may be broken here too. 

More information about the NeXus mailing list