System request

The System Request key, short SysRq, Swiss and U.S. keyboards SysRq (short for engl. System Request ), is a relic of old terminal keyboards on which the button to reset the keyboard or the change from one session to next causes. On PC keyboards, this function was first introduced in 1984 with the IBM Personal Computer / AT as a separate button, releasing the key number grew from 83 to 84. After the key of software was hardly used, contrary to expectations, IBM has the function of 1987 laid with the 101/102-tastigen MF2 keyboard as an additional function to the print button; the System Request function is realized now and still using the key combination Alt- pressure or for international keyboards Alt- PrtSc. The System Request key but still has its own distinctive scan code that does not match the print button, and can thus come to a notebook keyboards on a different key combination or omissions.

Function

Under Microsoft Windows, you can start using the key combination Ctrl and pressing twice by SysRq into the kernel, after this function has been enabled in the registry.

In newer versions of Linux, you can configure this button so that you can even with a blocked by a software or hardware fault terminal or X server, certain actions ( eg reboot with previous buffered write data to the disk) to perform. Only a few parts of the kernel must still be run to use this feature. This is called Magic SysRq key.

  • Computer Key
Scancode Esc key Scroll lock 8 (number) 9 (number) 4 (number) 6 (number) 3 (number)
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