It'd let you safely shutdown when the computer is locked up otherwise.
It'd let you safely shutdown when the computer is locked up otherwise.
They aren't exactly the same thing, I suppose, but there's enough functional overlap that if you already have one, it's hard to justify adding another. You don't want too many of these "escape sequences", because every kernel-side keyboard interrupt becomes a thing that:
* Userland doesn't get to use that keyboard shortcut any more.
* Someone might accidentally trigger, and if they don't know what's going on, they become stuck.
* It's another thing that anyone building a captive kiosk has to know how to disable.
It can also be challenging to actually input a magic-sysrq combo on many modern keyboards where sysrq isn't its own key, if it's labeled at all as some Fn-key contortion.
Ages ago I worked with a small team of young sysadmins who would often cause trouble for one another abusing things like sysrq, or poorly configured XFree86 instances without DontZap enabled (ctrl-alt-backspace termination, to a shell when startx/xinit is being used). Most of the time nothing malicious was actually done. But when you return to your screen-locked X desktop to find a fullscreen VC with a root shell blinking back at you and an empty history, guess what you'll at least have on the back of your mind for the rest of the workday?