Other Uses
Under DOS, malfunctioning foreground software could make the entire computer unresponsive. Third-party TSRs existed that used SysRq to provide a form of “panic button” to terminate the program and return the user to the DOS command prompt.
In Linux, the kernel can be configured to provide functions for system debugging and crash recovery. This use is known as the “Magic SysRq key”.
In Windows, SysRq (accessed by pressing Alt-PrtScn) copies a bitmap of the current foreground window into the system clipboard.
Microsoft has also used SysRq for various OS- and application-level debuggers. In the CodeView debugger, it was sometimes used to break into the debugging during program execution. For the Windows NT remote kernel debugger, it can be used to force the system into the debugger.
On the Hyundai/Hynix Super-16 computer, pressing Ctrl+SysRq will hard boot the system (it will reboot when Ctrl+Alt+Del is unresponsive, and it will invoke startup memory tests that are bypassed on soft-boot).
In embedded systems, SysRq key is usually used to assert low-level on RESET# signal.
Read more about this topic: System Request