[d2n-analysis-talk] Extracting the run end time from a CODA file

[Brad Sawatzky]

On Fri, 08 Oct 2010, Diana Parno wrote:

> I'm curious if there's a simple way to extract the time stamp at which  
> data stopped being written to a CODA file. I have encountered a run  
> that has about a tenth as much data as the HALOG end-of-run time  
> implies it should, and nothing looks wrong with the beam; I'm curious  
> what might have happened to it. The "run date" object in the THaRun  
> object that appears in the replayed file seems to correspond to the  
> start date/time, rather than the stop.

The brute-force way to do this would be to look at the header info in
the EPICS event data that get inserted every 5--30 seconds (can't
remember what frequency we set this to).

The timestamp is decoded in the THaEpics class, but I don't know if it
is propagated to the Tree (or what name it might have).

There is a relatively easy hack if you only want a quick check on a
single run though.  Login to adaq at adaql5 (or whatever) and run this:
 % evio2xml -ev 131 coda_file.dat | less
Look at the timestamp for the first epics event and quit 'less'.  It
should be very close to the timestamp in the Halog "Start of Run" entry.

Then run
 % nice evio2xml -ev 131 coda_file.dat.N > /u/scratch/dseymour/epics.out
(on whatever the last coda file for that run is).  Note that the command
is nice'd to minimize impact on the DVCS experiment, and that the output
is directed to your scratch directory so you don't burn space on the
adaqfs /home/ partition.

The text file is like to be fairly large, so remove it when you're done.

-- Brad

-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
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