Opening and closing the output files only once per run solves the problem!

There's much for me to learn from all the code examples offered in this thread. Even in my halting, pidgin Perl code, though, opening and closing output files only once per run made a world of difference. I'm now getting run times under Win32 comparable to what I was getting under Linux.

Not directly a Perl question, but I'm curious why Linux handled my badly written code so much more effectively than did XP.