Nađoh:
"Sometimes software has the potential to completely lock up the system. When this happens, a BIOS interrupt is the only input that can be generated. The SysRq BIOS interrupt handler can be configured as a form of "panic button" to gracefully terminate the program or reboot the system."
Znači, ne služi ničemu, osim ako ne konfigurišeš sistem tako da postane "panic button". Heh :?
Wikipedia
http://en.wikipedia.org/wiki/SysRq