Hey. I've cabalised the FastPackedString module from darcs, used in h4sh, as the `fps' library. fps provides mmapped and malloc'd packed strings (byte arrays held by a ForeignPtr), along with a list interface to these strings. It lets you do extremely fast IO in Haskell. For example, the shell identity function written in Haskell (i): $ time cat 200M > /dev/null 0.00s user 0.19s system 2% cpu 6.481 total $ time i 200M > /dev/null 0.00s user 0.00s system 0% cpu 0.172 total $ time cat 200M > /tmp/f 0.00s user 0.38s system 1% cpu 27.932 total $ time i 200M > /tmp/f 0.00s user 0.48s system 7% cpu 6.454 total The FastPackedString module was originally written by Bryan O'Sullivan, it was rewritten to use UArray by Simon Marlow, then rewritten and extended to support slices, mmapping, ForeignPtrs and lots of other stuff by David Roundy and the darcs team. This version fixes a couple of bugs related to conformance to List, adds a testsuite, and makes the code conveniently available as a cabalised library. Get it: http://www.cse.unsw.edu.au/~dons/fps.html darcs get http://www.cse.unsw.edu.au/~dons/code/fps -- Don Stewart