Certain Magic SysRq sequences are now disabled by default in Ubuntu. You can re-enable them by editing /etc/sysctl.d/10-magic-sysrq.conf. Alternately, you can e

Certain Magic SysRq sequences are now disabled by default in Ubuntu. You can re-enable them by editing /etc/sysctl.d/10-magic-sysrq.conf. Alternately, you can enable them temporarily by # echo 1 > /proc/sys/kernel/sysrq (Or substitute "1" by the number described in magic-sysrq.conf, above)