[open] Crash During Experiment (Due to Synchronization Error?)
Hi,
I have been running an experiment for a while, but today Open Sesame crashed right in the middle of it with the following error message:
Error while executing inline script
phase: run
item: end_EEG
line: 114
exception message: internal 32-bit counter passed through zero, please resynchronize ( call .synch() once again )
exception type: Eggog
Traceback (also in debug window):
File "dist\libopensesame\inline_script.py", line 154, in run
File "", line 3, in
File "C:\Documents and Settings\EGI\Desktop\opensesame\egi\simple.py", line 114, in ms_localtime
Eggog: internal 32-bit counter passed through zero, please resynchronize ( call .synch() once again )
I was recording my 25th participant when the crash occurred, and this is the first time I have seen this error (no problems whatsoever before). I use the current version of the software, connected to an EGI Net Station EEG setup. I have been unable to recreate the error after the failed session had ended.
Before the failed session, a colleague of mine had dis- and reconnected the Ethernet cable connecting the computer running Open Sesame with the EGI system. Some TCP/IP related settings had been changed and restored, but I guess this shouldn't be the issue seeing as how the problem has disappeared?
I have no idea what may have caused the error, and therefore don't know how to prevent it from happening again. Any help regarding potential causes (and possible solutions 
... ) would be greatly appreciated!
Thanks in advance!
Thomas
Edit: Formatting
Comments
Hi Thomas,
This error comes from the Python library of your EEG set-up (
egi), so for a definitive answer it's best to ask the developers of that library. However, because the error message is quite informative, I'll venture a guess.It seems the EEG device has an internal timer that uses a 32 bit timestamp. This means that it cannot go above 4,294,967,295 (=2^32-1). When that happens, the timer will overflow and go back to 0. And that seems to be what happened in your case. Because the timer can run for a long time without an overflow occurring, this is a pretty rare event--but it should happen every once in a while.
There's probably a function that you can call to reset the counter to 0 at the start of your experiment, to avoid this problem. That could be the
synch()function that is referred in the error message, but you should be able to find this in the documentation of theegilibrary (which is not part of OpenSesame).Hope this helps and happy holidays!
Cheers,
Sebastiaan
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Hi Sebastiaan,
Thank you very much for your quick reply! This will definitely prove to be helpful!
Best,
Thomas
BTW: a similar bug happened on YouTube recently.
Haha, that's hilarious.
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