This is from c.l.py.  There's not enough info (e.g., 
which OS, which compiler, which Python), but in case 
anyone is wondering what to do with their IA64 box ...

From: John Wiegley
Sent: Thursday, August 16, 2001 6:14 PM
To: python-list@python.org
Subject: Problem with zipfile between 32-bit and 64-bit

Using the test script below, run it once on an Intel
32-bit platform.  This produces test.zip, which
extracts hello.py.

Then take the test script and test.zip to an ia64
platform, and run it again.  The file it extracts has
0 bytes.

I've run into other problems between ia32 and ia64,
such as bad checksums, and was wondering if anyone
knew anything about this?

Thanks,
  John Wiegley <johnw@gnu.org>

----[ file: ziptest.py ]-------------------------------
---------------
import os
import zipfile
import string

if not os.path.exists('test.zip'):
    zip = zipfile.ZipFile('test.zip', 'w')
    zip.write('ziptest.py', 'hello.py')
    zip.close()

zip = zipfile.ZipFile('test.zip', 'r')
if hasattr(zip, 'namelist'):
    files = zip.namelist()
else:
    files = zip.listdir()

for file in files:
    file = apply(os.path.join, string.split
(file, '\\'))

    data = open(file, 'wb')
    print "unarchiving", file
    data.write(zip.read(file))
    data.close()

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The zlib module seems to use struct.pack('l') for packing 
some values, which should be 64-bits on a 64-bit platform.
Maybe that's the bug.

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Should they really be 64 bits on a 64-bit box?  Looks like 
zipfile.py is using a standard (as opposed to native) pack 
format, in order to ensure platform-independent layout.

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Could someone try this again?  binascii.crc32() returned 
different results on some 64-bit boxes than on 32-bit boxes, 
and that's been fixed.  See

<http://www.python.org/sf/576327>

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I tested this on x86/Linux and alpha/Tru64 and it seems to
work.  Closing.