Just for fun, I was able to filter a 1 Terabyte stream through a Haskell program, using Data.ByteString.Lazy, with a constant 2M heapsize, in $ time ( repeat 100 ; cat /home/dons/data/10G | ./lazy > /dev/null ) 12752.37s user 4069.35s system 58% cpu 8:03:11.42 total 8 hours. Just so we can say it is possible :) -- Don