Oh and he never said it was not useful. It's just that if the program has
root privileges then chroot is worthless. If you do it properly with
carefully controlled file discripters and proper setuid and that sort of
thing chroot can be useful, it's just much more difficult to get right then
Meanwhile with things like BSD Jails, Linux LXC, or Solaris Zones are
designed to be easy for admins to make applications isolated in a proper
manner and can be used with lots of applications that would never really work
out with chroot.