Ctrl-Alt-Backspace change [was Re: Announcing Fedora 11 Alpha (blink)]

Christopher Beland beland at alum.mit.edu
Sat Feb 7 21:17:21 UTC 2009


A long Xorg thread which discusses this starts here:
http://lists.freedesktop.org/archives/xorg/2008-September/038786.html

This points to a number of case studies, collected at:
http://bugs.freedesktop.org/show_bug.cgi?id=10510
[copied below]

Apparently this combination is easier to hit accidentally than you might
think, due to similar keyboard shortcuts in various applications.

This bug includes a proposal that a different, less dangerous key
combination be chosen, but apparently the default was simply changed to
disable zapping entirely.

-B.

== Feature request ==

Xorg should have a config file option to make it harder to kill it than a mere
Ctrl+Alt+Backspace.  Perhaps Control+Z+A+P all at the same time would be a
better key combination.  Yes, that's those four keys held down at once.

Or perhaps Control+Alt+Z, then Control+Alt+A, then Control+Alt+P.

Or maybe you could instead use the key combo Control+Alt+Backspace pressed
three times.  The first and second time you press it, the PC speaker would emit
a beep and the keyboard Caps/Num/Scroll Lock LED would blink a few times and X
would attempt to show a warning dialog on the screen.  The third time you
pressed it, X would die.

Although it seems few distributors use DontZap by default, perhaps they would
use this new option if it were implemented.  Or maybe you yourself could enable
it by default.

== Example evidence ==

"We routinely use backspace to kill a character, C-backspace to kill a word,
C-x backspace to kill a sentence, etc. And inevitably, we press C-M-backspace
trying to kill an s-expression, just to find ourselves wondering why the screen
suddenly turns black for a moment before the login screen appears again. Yup,
we zapped the X server, because that is what C-M-backspace does."
--http://www.foldr.org/~michaelw/log/programming/lisp/dontzap-emacs (Emacs's C
and Java modes use the Ctrl+Alt+Backspace key combination to delete the
{}-enclosed structural block to the left of the cursor.)

"How can I configure X not to shutdown when I accidentally press
control-alt-backspace?  This happens a lot, believe it or not, while I'm using
emacs.  If X were to pop up a confirmation dialog, that
would be even better." --
http://www.answers.google.com/answers/threadview?id=38992

"In the terminal programs I use, alt-backspace erases the word to the left of
the cursor.  This is very handy, but when my thumb slips just a small amount it
also presses the ctrl key..." --
http://www.lugod.org/mailinglists/archives/vox-tech/2005-09/msg00046.html

"A word to Alt+Backspace and Shift+Alt+Backspace: I have noticed the danger of
shutting down X-Windows when you accidentally hit Ctrl+Alt+Backspace instead of
one of the two other keystrokes. So, this might be arguable that users might
accidentally mistype a keystroke thus losing some work (as I did :-))" --
http://bugs.kde.org/63540

With sticky keys: "I crashed my system accidentally - I wanted Ctrl-Backspace,
and got
Ctrl-Alt-Backspace!
Perhaps sticky keys should not stick the combinations:
Ctrl-Alt-[Del|Backspace|Esc]" --
http://lists.freedesktop.org/archives/xorg-bugzilla-noise/2004-September/003354.html

For more examples see:
http://www.google.com/search?q=accidentally+hit+%7C+press+%7C+hitting+%7C+pressing+control+%7C+ctrl+alt+backspace+x%7Cxorg




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