[Zope] popen2, popen3, popen4 and Zope

[Dennis Allison]

The popen libraries don't seem to function properly when used from 
a Zope External Method or product.  I use the standard idiom -- 
	i, o = os.popen2( cmd )
	i.close()
	res = o.read()

but Zope seems to hangs on the read whenever cmd is anything of any
complexity, for example, a shell script that fires off a python instance
that detaches itself and then initiates another insance of Zope. Is the
problem a threading issue? Is there a preferred mechanism for spawning a
process?