On 15:37:46 Dec 31, Stuart Henderson wrote:
> Even so, it still allows recovery from some serious problems without
> touching the machine. There are quite a few situations where this could
> be very useful, though it might not be worth the extra expense and
> complexity of adding an external device, watchdog timers aren't too
> uncommon in PC hardware these days.
Correct me if I am wrong but I believe it was this that saved the Mars
lander from total disaster a few years ago. I heard it was due to the
brilliant idea of some Indian professor. I don't remember much about it
now.
> In the case of the hardware Nick mentioned, there should be a watchdog
> timer in the I/O controller hub (82801AA ICH); adding support for this
> might be as simple as adding the device ID to /sys/dev/pci/ichwdt.c then
> test by setting sysctl kern.watchdog.auto=0 and kern.watchdog.period=30
> and wait 30 seconds for it to reboot. See watchdog(4) and watchdogd(8)
> ("man -k watchdog" gives a list of device drivers supporting watchdog
> timers).
Watchdog is a great idea. And for embedded/real time systems it might be
inevitable and even life saving. But since I lack experience my ideas
could be wrong.
> The main docs for driving the ICH* watchdog timers are here:
> http://download.intel.com/design/chipsets/applnots/29227301.pdf
> (also see http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/ichwd/
> which supports 82801AA).
Wow! Great!
I believe Intel gives very good documentation for everything except
wireless chipsets. ;) Theo should have more to say on this. ha ha
Many thanks Stuart.
-Girish
