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Sun Feb 20 16:52:19 PST 2005


  http://www.tuxedo.org/~esr/jargon/html/entry/molly-guard.html

molly-guard /mol'ee-gard/ n. 

[University of Illinois] A shield to prevent tripping of some Big Red
Switch by clumsy or ignorant hands. Originally used of the plexiglass
covers improvised for the BRS on an IBM 4341 after a programmer's
toddler daughter (named Molly) frobbed it twice in one day. Later
generalized to covers over stop/reset switches on disk drives and
networking equipment. In hardware catalogues, you'll see the much less
interesting description "guarded button".

   -- Mitch

On Mon, Feb 14, 2000 at 12:34:13PM -0800, ME wrote:
> On Mon, 14 Feb 2000, Walter Coole wrote:
> > Subject: Power Switch
> > 
> > Does anyone know how to tell Linux to use the soft power switch on my
> > newish Compaq?
> > 
> > What I want is: when my three-year-old pushes the switch, it does a
> > clean shutdown.  Windows (bleah) knows how to do this, so the hardware
> > is there.  My old HP-UX system could handle this, but I don't know if
> > Linux knows this trick.
> 
> Since Linux is open source, you do have access to the kernel source code.
> The following two sections deal with control-alt-delete triggers and
> handling.
> 
> A big-wrench method of attack could include modifying your kernel source
> to del with another key sequence (assuming the soft-keys on your keyboard
> generate keyboard interrupts and are not part of an extra serial port
> communications.)
> 
> starting with an examination of:
> kernel/sys.c
> drivers/char/keyboard.c
> 
> Something tells me that there is an easier solution than this, but I have
> not had a need for it, so I never researched it.
> 
> An older document (circa 1995) on the keyboard can be found here:
> http://www.win.tue.nl/math/dw/pp/aeb/linux/kbd/Linux_keyboard_driver
> A more recent document on keyboard/console stuff:
> http://linux.com/howto/Keyboard-and-Console-HOWTO-8.html
> 
> Another suggestion is examination of
> /etc/inittab for init
> If you can manage to map the pressing of a key sequence to the sending of
> a signal "SIGINT" to init, then you can effectively perform a reboot.
> 
> Check out "man loadkeys": it allows you to map strings to key sequences
> from the console, but I do not see anything about assigning keys to
> running scripts. Perhaps map the key sequence for that key to send the
> same sequence as a control-alt-delete? If this is possible, it may offer a
> simple fix for you.
> 
> ***
> Hopefully, someone else has experience with this and can offer you
> direction more orthodoxed than these suggestions.
> ***
> 
> Unless you can find a quick and easy solution to run a program, or
> configure a running program to interpret the key-sequence/signal from the
> console, I would look into modifying the keyboard driver in kernel land. 
> If you know the key-code/signal generated for that key, then you may be
> able to add an check for it as well as control-alt-delete when it is
> pressed, and perform the same reboot. 
> 
> Maybe add a patch to the kernel for a new kernel option, and submit it to
> the developers for integration into the main tree?
> 
> (A configure option to choose "y" and then enter the key sequence you want
> to use, and what you want it to do.)
> 
> Sorry I couldn't help,
> -ME
> 



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