[PLUG] Zot's power cycling for Linux

Keith Lofstrom keithl at kl-ic.com
Fri Apr 23 17:56:02 UTC 2004


Zot writes:
> I have a remote machine that is locking up.  I want to be able to shut
> power down for 5 minutes, and then power back up.  The power supplies
> have a timeout reset on them, so flicking it on and off will not
> work....

Have you considered a watchdog timer board?  These run around $100, IIRC,
and will do a hard reset of the machine if they are not tickled by code
every so often.  I was having problems with a machine back in my BSDI
days, I got a such a card, wrote a BSDI driver based on the supplied Linux
driver,  and it worked!  When the machine went zombie and stopped tickling
the watchdog board, it would wait 30 seconds and then do a hard reset.

Turned out to be better to replace the flakey machine, though.  I think
I still have the old ISA card around someplace.

In any case, these cards come simple or complex, PCI or ISA, sometimes
with additional connections for switching an external relay on and off,
or activating when the phone rings and the modem doesn't answer.  Lots
of nifty options.  

Another alternative would be to temporarily attach a second linux box
with a signal from the parallel port controlling a 5V relay.  You could
have two machines control each other this way.  Finally, a task slow
enough to run on a 386-12 machine!  That's 0.012 GHz for all you young
people.  :-)

Keith

P.S.  Dollars to donuts this thread gets hijacked without changing
subject lines.

-- 
Keith Lofstrom           keithl at ieee.org         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs




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