force a linux reboot- when shutdown and reboot -f won't work

Just found this excellent post about how to restart a linux system that is ignoring both shutdown and reboot -f commands (in my case due to problems with an adaptec raid controller): http://linax.wordpress.com/2009/02/16/linux-force-reboot-and-shutdown/
In case it disappears, this is the content:

Linux Force Reboot and shutdown

Filed under: Linux — Nasser Heidari @ 09:42

Force Reboot :

#echo 1 > /proc/sys/kernel/sysrq

#echo b > /proc/sysrq-trigger

If you want to force shutdown machine try this.

#echo 1 > /proc/sys/kernel/sysrq

#echo o > /proc/sysrq-trigger