Re: Automatic Reboot, Fsck and a PCI HW-Watchdog

[mgraffam mhv net]

On Sun, 31 May 1998, Gavin wrote:

> How would i best reboot my alpha say .. every 24 hours ? 
> shutdown command in a cron job .. would that woek .. (and be a good
> idea)?

shutdown should work, yeah. You'd probably want it give the users 30
minutes or so before actually rebooting so that any work can be saved..
and give root a chance to stop it.

> and could the init script in RH 5.0 be modified so that fsck runs .. no
> matter what ?

I can't see any reason why not.. as it stands now the logic for checking
whether to launch fsck is in the script.. just change the logic. 

> At the same time i am looking for a PCI card that can detect if the
> system has crashed, and reboot 
> the alpha . anyone know if sutch a thing is possible and exists ? 

You want what is called a watchdog card. There is a software "watchdog"
solution, but obviously this won't catch all crash situations.

I don't know if the watchdog drivers work under Linux/Alpha .. but they
do work on Intel. 

If they _don't_ work on Alpha, feel free to fix it :)

OTOH, you could do something like this (which is a solution I came up
with for a VME based machine):

I took an 8051 microcontroller and hooked it up to the serial port.
If the 8051 stops getting a byte every second for more than 3 seconds
it supplies 5 volts to the reset pin on the mainboard and waits until
the board starts sending bytes again, then it falls back into the timing
loop. Then I just wrote a small program that dumps a's to the serial port
and put it in my startup configuration. 

This solution is a whole lot more fun than buying a watchdog board!
But then, I'm a geek so my idea of fun may be radically different than
yours :)

Michael J. Graffam (mgraffam@mhv.net)
http://www.mhv.net/~mgraffam -- Philosophy, Religion, Computers, Crypto, etc
"..the isle is full of noises, sounds and sweet airs that give delight and
hurt not. Sometimes a thousand twangling instruments will hum about mine
ears, and sometimes voices.." Caliban, Shakespeare's "The Tempest"