On Tue, 3 Nov 1998, David Wilburn wrote:
> Perhaps using watchdog hardware might be simpler then. You could execute
> shutdown -h 0, then of course the watchdog wouldn't be updated by the
> computer when it is halted, so a few seconds or minutes later, the
> watchdog hardware flips the power switch. I'm really not incredibly
> familiar with watchdog hardware (where to get them, how much they cost,
> whether they can just shut off the power instead of cycling it back on
> again, etc.), so take this with a very large grain of salt. Watchdog
> support has been a kernel option for awhile now, though.
The watchdog cards don't always work really well. BTW, the one I have (the
originally supported card - the WDT501) works by hitting the reset line -
not doing a true power cycle.
Sure, the detection part works great - it's the resetting the system part
that I have trouble with.
I have this card in a P6DOF-based SMP system, and when the watchdog card
fires, it flips the reset line so fast (we're talking a fraction of a second
pulse here, slowed/shortened by the relay) that the motherboard hangs
permanently instead of rebooting. I spent some time trying to program the
card's timer for a longer pulse to no avail. Yech - had to disable the
hardware watchdog and settle for the software watchdog. Some day I intend
to hack together a pulse-lengthener out of a 555 or something, but who knows
when I'll get around to it...
-Andy
Global Auctions
http://www.globalauctions.com
