Excerpts from David Corbin's mail of 14 Feb 2005 (EST):
> I have an applciation that spawns multiple threads.  Each thread will
> do a few things, including running a number of external applications
> using back-ticks.  
> 
> Observation tells me that when I do this on Windows, it seems like
> only three threads run simultaneously.  Once one of those threads
> finishes, the next one starts up.

I'd be surprised if Ruby allowed more than one thread to do a system()
call at a time, Windows or not. Perhaps that would explain the behavior?
If you fake those shell calls, do the symptoms persist?

Ruby is definitely not limited to three concurrent threads at a time. :)

-- 
William <wmorgan-ruby-talk / masanjin.net>