I didn't care about the os.system() call contention because that's what 
caused the logging problem and that blah.txt file contention should not 
cause logging to fail.

I also had the join calls originally but took them out to simplify the 
code since it seemed to run correctly either way - if this were 
production code, I'd have left them in.

The revised script works for me on windows 2.6.2 (the version I 
upgraded to) but I think it just puts locks around the problem and 
masks the true problem out.  It appears something in os.system() is 
crashing logging and that shouldn't happen.  If locks need to be 
placed, they should be placed around the problem within os.system() or 
within logging, if needed.

Please take the locks off the os.system() calls and see why logging is 
failing when those calls are made.  Remember, this is a test script I 
wrote from scratch with the express purpose of making logging fail from 
multiple threads so you could catch it in a debugger or something.  
Changing the script to make it work misses the point.