> How do you measure importance? Z/OS is not important to many
> people in the world, but to those to whom it is important, it is
> _very_ important, in a very tangible way. It was certainly
> important enough for someone to port Python to it. :)

But is it important enough to cause a lot of work for the maintainers
of Python, not just once (reviewing your mega-patch) but also in the
future (making sure that the Z/OS support doesn't break)? We have
accepted mega-patches for minority OS'es in the past, and our
experience has unfortunately been that the contributors of such
patches inevitable lose interest and the Python core developers are
stuck with maintaining the patch -- or ripping it out, which is just
as much work but at least promises that there will be no more work
related to this issue in the future.

I strongly recommend an alternative: the Z/OS community should
maintain the patch set themselves. That way the burden of keeping it
working is to those who benefit. It also makes it possible to decide
not to upgrade to a newer version of Python because there aren't
enough benefits. This is done for example by Nokia for its port to
S60.

> The character set of EBCDIC is a superset of the character set of
> ASCII. In fact CP1047, the variant used on z/OS, has the same
> character set as Latin-1. Only the encoding is completely
> different.

And there's the crux -- too much code (not just in the core but also
in the library and in 3rd party code) assumes that the ASCII
*encoding* is used in 8-bit strings. Breaking this will break tons of
stuff. Glancing at your code it seems that you haven't tried the
socket module or the higher-level internet modules to contact web
servers on the internet...