I grabbed a copy of the Touch and Farber paper cited earlier in this
thread, which seemed to deal with FTP. This described a pre-send selection
algorithm of sending everything in the currently selected directory. The
Boston University system used a simple 1-level probablistic model to pick
the best candidates for pre-send, and used fare less extra bandwidth,
though with a higher probablity of a cache-miss. There's lots of stuff to
tune with speculation.
Simon