When I built the PickAxe on my Intel OS X box, I used to see a number of threading issues if I mixed the use of sleep() and threads. These problems seem to have been fixed.9.1p0 works just fine. However, when I tried building the book on a PowerPC box, they all came back. I see random hangs and other unpredictable behavior. Is anyone successfully running 1.9.1p0 on a PowerPC OS X box? Would it be reasonable for there to be such a major different in the reliability of threads? Dave