Intermittent freeze

We are running a study at the moment in which we present 7 tasks using inquisit.  Each task is a separate inquisit <expt> and are batched together (DOS batch).  The batch is presented to 10 subjects simultaneously (10 separate laptops).  Thus in a single session 70 tasks are run.  We have encountered an intermittent problem where inquisit sometimes freezes and the only way to proceed is to kill the program using task manager. 

It happens about 3-4 times (out of 70) which does not sound like much but it is quite detrimental for the study.  There is no consistent pattern as to which of the 7 tasks is effected or which laptop.  It appears to be different every time.

The only consistency is that it seems to happen when an <htmlpage> page is being presented as an instruction.  We get the instruction window (with buttons at the bottom) but no HTML content and the app freezes.  Each task has a <htmlpage> being presented as preinstruction and postinstruction to the <expt>.

I know that intermittent problems are difficult to locate but any advice on where to start looking would be greatly appreciated.

Thanks

 

 

This sounds like a bug in 3.0.3.0. The latest update 3.0.3.1 has a fix for this. You can download the desktop version here:

http://www.millisecond.com/download/win/Inquisit_3031.exe

If you are using the web version, login to your webscripts page, click Settings for you web script, and select version 3.0.3.1 on the first page of the registration wizard.

-Sean

If you still run into this after updating to 3.0.3.1, you could try working with some delay settings in your batch files. This might allow processes to stop properly before they're invoked again (e.g. the Internet Explorer Engine that Inquisit uses to display HTML instruction pages). The following batch syntax (tested on Windows XP) will introduce a 5 second pause before starting the next script:

"C:\Program Files\Millisecond Software\Inquisit 3\Inquisit.exe" "C:\First.exp"
delay 5
"C:\Program Files\Millisecond Software\Inquisit 3\Inquisit.exe" "C:\Second.exp"

Best,
~Dave

Thanks for the prompt response.

I tried version 3.0.3.1 but unfortunately it did not solve the problem.

So then I tried Dave's suggestion of putting a delay in between the tasks.  I can't quite see how this will help though because the problem seems to be with the <htmlpage> presented as a postinstruction to an <expt>.  Thus that task does not actually exit, but killing the task with task manager will allow the batch to continue as expected.  Nonetheless all suggestions are welcomed and worth trying.

Inspired by Dave's suggestion I also put in a blank 1500 msec trial at the end of the task just prior to the postinstruction.

I have tested these changes once per machine and there has not been a  freeze.  However this is not confirmation of a fix because the problem was very intermittent in the first place. The real test will come tomorrow when we run 4 sessions of 10 subjetcts.

I will be sure to post the result, but in the interim any other suggestions would still we welcomed.

Cheers and thanks

Sean

From your first post it wasn't quite clear that this only seems to happen with postinstruction pages. You're absolutely right that in this case my suggestion won't make any difference. Here are a few other things to consider:

(1) Look at the HTML code of the postinstruction pages. Maybe there's something odd in there that's throwing the IE engine off track. For example, HTML pages generated by MS Word have some really weird code embedded in them (although this usually doesn't disturb MS Internet Explorer all that much...).

(2) If you present pictures on the postinstruction pages try to optimize their filesize so the IE engine doesn't have to load a 2 MB JPEG. (It is very improbable though that this has anything to do with the freezing problem you're experiencing).

(3) The radical solution: Replace all your HTML instruction pages with either Inquisit's standard <page> elements or even use normal <trial> elements to present your pre- and postinstructions. Of course, changing this for all scripts is a lot of work (maybe more than can be achieved on a tight schedule).

Best,
~Dave

Sean,

Can you email the experiment along with any pictures, html files, etc that it uses? You can just send it to our support email address. I'll take a look and see if I can figure out what's going on.

Thanks,
Sean

Hey guys,

I'm currently also creating a script using the htmlpages element (extensively) and I'm running into the same problem. In my script there also doesn't appear to be any reason why the script freezes. For the record: I'm using version 3.0.4.0 of Inquisit.  

I've attached the current script I'm running. As was mentioned by seanfitz, it happens real sporadic. I really hope you can help, because the option Dave offered is possible (we did that in other scripts), but is really ugly and a lot of work....

Update: It doesn't matter if you run the script for a user or if the monkey does it, in both cases it can freeze

Ivor