monitor disc/net i/o per process?

[gregory mott <gmott ultra net>]

does anyone know of an app useful for monitoring disc and/or network i/o
per process?

basically i'd like something just like top, but that can show (putting
the most recent at the top of the list, of course) how long it's been
since each process did some disk i/o, or did some network i/o, etc.