subprocess.Popen hangs at times?

[Kenneth McDonald]

When making calls of the form Popen(cmd, shell=True,
stdout=subprocess.PIPE), we've been getting occasional, predictable
hangs. Will Popen accumulate a certain amount of stdout and then block
until its read? We don't want to use threads, so just want to read the
entire stdout after the subprocess has finished.

Thanks,
Ken