shutting down computer using /dev/ttySx
On Tue, Dec 11, 2001 at 01:46:11PM +0900, Olaf Meeuwissen wrote:
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> Olaf Meeuwissen <olaf@epkowa.co.jp> wrote:
>
> > I'm maintaining a (small-time) group server for our department. In
> > order to satisfy company policy requirements I need to provide a way
> > to shutdown the server in case of emergencies. Our network admin was
> > kind enough to give me two alternatives:
> >
> > 1) provide an on-screen shutdown button
> > 2) provide a shutdown user account (and document its usage)
> >
> > Suggestions, discussions of pros and cons welcome,
>
> Thanks to everyone who responded. I should have been a little clearer
> on the system setup. The machine in question consists of a main unit
> and a bunch of externally attached hard disks connected to a network.
> It has no monitor, keyboard (what Ctrl-Alt-Del?) and mouse.
That is pretty simple :-)
run this script during the boot with "nohup /dir/send.sh &"
--- begin of send.sh ---
#!/bin/sh
while true; do
echo -n "pzn" > /dev/ttyS0 #send 3 bytes to serial port
sleep 1
done
--- end of send.sh ---
and also run this during boot "nohup /dir/receive.sh &"
--- begin of receive.sh ---
#!/bin/sh
head -c 9 /dev/ttyS0 #waits to receive 9 bits from serial port
echo -n "\007" > /dev/console #beep the pcspeaker
sleep 1
echo -n "\007" > /dev/console #beep the pcspeaker
sleep 1
halt #shutdown the system
--- end of receive.sh ---
then put a switch that when pressed shorts pins 2 and 3 of your serial
port /dev/ttyS0.
that is it. just press the switch for 3 seconds to shutdown the machine.
if it does not work, then configure setserial to use "no flow control"
on /dev/ttyS0
Good luck,
Pedro
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