Linux Kernel in a Nutshell

Name

MAGIC_SYSRQ — Magic SysRq key

If you say yes here, you will have some control over the system even if the system crashes for example during kernel debugging (e.g., you will be able to flush the buffer cache to disk, reboot the system immediately, or dump some status information). This is accomplished by pressing various keys while holding down the SysRq (Alt+PrintScreen) key. It also works on a serial console (on PC hardware at least), if you send a BREAK and then within 5 seconds a command keypress. The keys are documented in Documentation/sysrq.txt. Don't say yes unless you really know what this hack does.