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Hi
I would like to reboot/halt my system when I press the reset
button ( beside the power button) on my computer.

the other day my system went wild. I was trying to use a dvdram
disc as a share in samba. While copying files to it, the keyboard
suddenly
stopped responding and the console displayed tons of messages
real fast.

I pressed the reset button as thats all I could do, and it reset power
but I would like it to reboot. Is there an option in inittab for this?
Something like the entry for ca:ctrlaltdel ? So that in case I
cannot salute I can alteast reset the computer and be assured
that the shutdown is gracefull ?

Thanks!

dmedhora@gmail.com wrote:
> Hi
> I would like to reboot/halt my system when I press the reset
> button ( beside the power button) on my computer.
>
> the other day my system went wild. I was trying to use a dvdram
> disc as a share in samba. While copying files to it, the keyboard
> suddenly
> stopped responding and the console displayed tons of messages
> real fast.
>
> I pressed the reset button as thats all I could do, and it reset power
> but I would like it to reboot. Is there an option in inittab for this?
> Something like the entry for ca:ctrlaltdel ? So that in case I
> cannot salute I can alteast reset the computer and be assured
> that the shutdown is gracefull ?
>
Your reset button should do just that: make the machine stop whatever it is
doing and do the BIOS stuff, the last step of which is to reboot your
machine. The reset button should not reset the power, but just the machine's
hardware registers and start the BIOS. If it diddled the power, either you
hit the wrong button, or something else is wrong. Perhaps a BIOS setting can
make the reset button do something else, but I do not know of one like that.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 20:35:02 up 17 days, 5:44, 3 users, load average: 4.25, 4.25, 4.10

On 30 Aug 2006, in the Usenet newsgroup comp.os.linux.setup, in article
<1156979187.726537.260980@74g2000cwt.googlegroups. com>, dmedhora@gmail.com
wrote:

>I would like to reboot/halt my system when I press the reset
>button ( beside the power button) on my computer.

Assumption: x86 type system (there is no reset button on a Mac, or most
other hardware that I'm aware of).

>the other day my system went wild. I was trying to use a dvdram
>disc as a share in samba. While copying files to it, the keyboard
>suddenly stopped responding and the console displayed tons of
>messages real fast.

Sounds like a hardware problem - hope you've got known good backups.

>I pressed the reset button as thats all I could do, and it reset power
>but I would like it to reboot.

Not exactly sure what you mean by "it reset power". On Intel type of
hardware (includes AMD, Cyrix, and so on), the reset button shorts a
signal called "PWR_OK" to ground. This signal is normally _generated_
on startup by the power supply, and indicates that the voltage used
to power the CPU and/or logic is above a minimum. This signal connects
to the /RESET pin on the CPU, (and other chips on the motherboard that
have such a pin), and to the /RESET pin on each ISA, EISA, MCA, VESA,
and/or PCI card in the system. While the signal is low (shorted to
ground), nothing is running. If the signal is held low for some minimum
time (usually defined as some number of CPU clock cycles - 15 is a good
number, and that's about a quarter of a millionth of a second), while
the power supply is delivering something like rated voltage, when the
signal is released (goes high), the CPU starts executing the "Good
Morning, World" code in the BIOS. This involves testing RAM, seeing
what hardware it can talk to, and so on. There is no operating system
involved in this.

>Is there an option in inittab for this? Something like the entry for
>ca:ctrlaltdel ?

No - /etc/inittab is something that is run by the first application
to run _after_ the operating system is running. This is _LOOOOONG_
after the BIOS has done it's thing. See the fine HOWTO called

43309 Nov 5 2000 From-PowerUp-To-Bash-Prompt-HOWTO

which may be on your system, but is widely available on the web.

>So that in case I cannot salute I can alteast reset the computer and be
>assured that the shutdown is gracefull ?

Nope! The reset switch is worse than a "kill -9", as it completely halts
the CPU (and hopefully the disk drive controller) in it's tracks, RIGHT
NOW - Do Not Pass Go - don't even _think_ about $200. Unlike a kill -9,
there is no escape just because something is busy - everything is stopped
immediately. It the disk is in the middle of writing something, that's
tough bananas.

Now what you might have seen is the display apparently power cycle. This
may occur with the modern "power management" monitors, that will go to
sleep (the "green" LED changes to "amber") when the video drive ceases.
Seeing as how the CPU is stopped, there is no reason to expect any
video, and this would occur. Likewise, the keyboard would (when you
release the reset button) go into the same "Good Morning World" self-test.

There really isn't a clean way to _reliably_ grab a CPU by the shorts to
get it's attention when it goes berserk. The only thing that will work
is to reset it to a power-on state. There are several things that you
can _try_ such as SSH/Telnet/rsh/rlogin (somehow open a terminal session
over the net), try switching to an alternate console (you're probably
running X, so try pressing the left Ctrl and Alt keys, and perhaps the
F7 key - one more than the number of mgettys you are running out of
/etc/inittab - press the left Alt and F1 key to return to X), or even
try killing X with the left Ctrl, Alt, and Backspace key (which kills
X - though it will restart if you are using a GUI login). These actions
_may_ give you access to a command line, where you can start killing
things. I wouldn't count on it.

If this is a real server, you should have a UPS protecting it against
power outages. This _usually_ has the capability of causing a clean
shutdown when power fails. You _MAY_ be able to cause the UPS to tell
the system to shut down cleanly, but that assumes the CPU is even looking
at the UPS. In an "off the rails" condition, I wouldn't count on this
either.

Old guy

On Thu, 31 Aug 2006 19:20:58 -0500, ibuprofin@painkiller.example.tld (Moe Trin) wrote:

>On 30 Aug 2006, in the Usenet newsgroup comp.os.linux.setup, in article
><1156979187.726537.260980@74g2000cwt.googlegroups .com>, dmedhora@gmail.com
>wrote:
>
>>I would like to reboot/halt my system when I press the reset
>>button ( beside the power button) on my computer.
>
>Assumption: x86 type system (there is no reset button on a Mac, or most
>other hardware that I'm aware of).

x86 here...

Additional info (agree with what Moe wrote), the reset button is last
resort -- properly setup power button (BIOS -> 4 second delay, ACPI
setup) will trigger graceful powerdown on quick push, and power off
when held for 4 seconds. So power button behaves like Ctrl-Alt-Del.

I use reiserfs3 and have not lost file to unexpected loss of power,
I do kernel testing, sometimes need to hit reset...

Also, some devices seem not to be hooked to the /RESET signal you
describe, these need a complete power disconnect and then wait for
5V-standby to run down, power up to get 'proper' power-on reset.
Noticed with some NICs, powered up all the time for 'wake-on-LAN'.

Cheers,
Grant.
--
http://bugsplatter.mine.nu/

Grant wrote:
> On Thu, 31 Aug 2006 19:20:58 -0500, ibuprofin@painkiller.example.tld (Moe Trin) wrote:
>
> >On 30 Aug 2006, in the Usenet newsgroup comp.os.linux.setup, in article
> ><1156979187.726537.260980@74g2000cwt.googlegroups .com>, dmedhora@gmail.com
> >wrote:
> >
> >>I would like to reboot/halt my system when I press the reset
> >>button ( beside the power button) on my computer.
> >
> >Assumption: x86 type system (there is no reset button on a Mac, or most
> >other hardware that I'm aware of).
>
> x86 here...
>
> Additional info (agree with what Moe wrote), the reset button is last
> resort -- properly setup power button (BIOS -> 4 second delay, ACPI
> setup) will trigger graceful powerdown on quick push, and power off
> when held for 4 seconds. So power button behaves like Ctrl-Alt-Del.
>
> I use reiserfs3 and have not lost file to unexpected loss of power,
> I do kernel testing, sometimes need to hit reset...
>
> Also, some devices seem not to be hooked to the /RESET signal you
> describe, these need a complete power disconnect and then wait for
> 5V-standby to run down, power up to get 'proper' power-on reset.
> Noticed with some NICs, powered up all the time for 'wake-on-LAN'.
>
> Cheers,
> Grant.
> --
> http://bugsplatter.mine.nu/

Hi again,

The pc I use is a x86. It has a power on/off button and a reset button.
I was running linux and was trying to make a dvdram drive available
for read/write over samba. From a windows pc on my lan I was trying
to copy files onto my linux dvdram drive.

I gave it like 10 files all at once ( They were big files, like 10MB
each).
The operation hung. When I went over to the linux pc I noticed a
continuous display of messages on the console but I couldn't use
the keyboard or eject the disc..
I tried SSH from my windows pc to login to the linux pc, it didn't work
and took real long without any timeout or connection failure messages..

I use runlevel 3 on the linux machine, so
I even tried ALT-F2,3 etc to get another terminal but since the
keyboard
had hung I couldn't get any. I even tried to use hyperterm via a serial
port but that didn't work. Basically the cpu was hogged I guess. Not
sure.
So, I pressed the reset button. ( Now at work where I only have a power
button on my x86 which runs windows on pressing it once fast, windows
shutdowns first and then powers off ). I was hoping that it would
initiate
a shutdown sequence but it just rebooted immediately and the BIOS
restarted just as though I had done a normal start.

I looked into acpid ( still looking really ), and theres a section in
the man
page saying:
This example - placed in /etc/acpi/events/power - will shut down your
system if you press
the power button.

event=button/power.*
action=/usr/local/sbin/power.sh "%e"

The script power.sh gets called and will see the complete event
string as parameter $1

I'll try putting "shutdown -h now" in the action=
cheers.

On 30 Aug 2006 16:06:27 -0700, dmedhora@gmail.com
<dmedhora@gmail.com> wrote:
> Hi
> I would like to reboot/halt my system when I press the reset
> button ( beside the power button) on my computer.
>
> the other day my system went wild. I was trying to use a dvdram
> disc as a share in samba. While copying files to it, the keyboard
> suddenly
> stopped responding and the console displayed tons of messages
> real fast.
>
> I pressed the reset button as thats all I could do, and it reset power
> but I would like it to reboot. Is there an option in inittab for this?
> Something like the entry for ca:ctrlaltdel ? So that in case I
> cannot salute I can alteast reset the computer and be assured
> that the shutdown is gracefull ?
>
If ctrl-alt-del doesn't work, you can try the magic SysRq key. If you
have kernel source or a kernel-*-doc or linux-*-doc package installed,
the information should be in Documentation/sysrq.txt.gz. (Magic SysRq
has to be enabled in the kernel configuration.)


--
APL is a natural extension of assembler language programming;
....and is best for educational purposes.
-- A. Perlis