Applying the Unix Process Model to Web Apps
adam.heroku.com
adam.heroku.com
The example for a production environment, however, is pretty unpersuasive. Tools like Passenger (mod_rails) dynamically start and stop processes depending on load, number of requests, etc. That is much more useful than just saying "start four mongrels".
Erlang OTP has been doing this forever; this is UNIX catching up.