bci2000.org BBS

I've been recently experiencing problems with BCI2000 ver 3.0.3
I'm using g.tec g.USBamp equipment, on a Windows XP SP3 PC, with the latest drivers for Nvidia FX 5500.
for a P300 speller application experiment
The issue is that when I hit the "Set Config" button it take a lot of time since the "Start" button gets activated
I'm pasting the output of the "system log" window, so you can get an idea
2011-11-16T18:31:20 - Warning: gUSBampADC::Preflight: g.USBamp driver version = 3.
2011-11-16T18:31:21 - SignalProcessing confirmed new parameters ...
2011-11-16T18:31:21 - SignalSource confirmed new parameters ...
2011-11-16T18:36:37 - Application confirmed new parameters ...

It takes more that 5 minutes for the system to be able to run...
During that time the cpu load is more than 50% and as soon as the application confirms new parameters it drops down to normal

Honestly I don't know what the issue might be, since i'm using the same hardware


PS: I've tried version 3.0.2, and it works without waiting that much
what could be the issue?

Five minutes is quite a long time. We noticed a waiting time of a few seconds when pressing SetConfig with the P3Speller application, and removed some bottlenecks that were introduced between 3.0.2 and 3.0.3. So you might try the current SVN version of BCI2000, and see whether that solves your problem.

Apart from that, your long waiting time might be due to a high screen resolution, in conjunction with a large number of bitmaps (icons) to present on the subject's screen. BCI2000 will cache all stimuli as bitmaps in memory, resized to screen resolution, such that it is able to quickly deliver them on screen. However, with large displays, and/or a large number of images, this will exhaust the machine's physical RAM, such that bitmap data will end up in the machine's page file on disk, which is much slower than RAM, resulting in delayed stimulus presentation.

The solution to this problem is to choose a reasonable resolution for the subject's screen. E.g., a resolution of 800x600 or even 640x480 should be sufficient for most stimulation experiments, given the image content and the subject-screen distance (this used to be standard TV resolution 10 years ago!). E.g., reducing from 1680x1050 to 640x480 will reduce memory consumption by a factor of 5.75.
Also, reducing color depth to 16bit color (if available) will reduce memory consumption by an additional factor of 2, resulting in an overall reduction by a factor of 13.5.

Regards,
Juergen