I was unable to reproduce the situation using a simple program just walking through all files>4K, with or without the seek, and computing their shasums. Only some fluctuations of about 500MB in memory consumption.
I'll look at this when I get more time, taking in consideration the suggestions here posted. For the time being, my work is done. With a small buffer size (16k) the results produced were correct and no memory was leaked! If I can find any explanation (if not embarrassing :-) ), I'll post it here. Thank you all. Paulo -- https://mail.python.org/mailman/listinfo/python-list
