[flopunctro]

Some enterprise-grade server platforms already have this functionality, it's called a "watchdog". Linux supports this since (at least) 2.4.

I've been using this with HP ProLiant servers and (for me, at least) it has always worked as intended.

For more info, search "linux watchdog timer".

[wongarsu]

It would also be fairly simple to build for any computer using just an arduino or a raspberry pi. The computer could send a periodic signal over the serial port, if the arduino doesn't receive a signal for some time it shorts the mainboard's reset pin, causing a reboot.

[qb45]

I think they are common on Intel systems, my old laptop with ICH7-M chipset has one.

[hamiltonkibbe]

You'd be hard pressed to find a processor without a WDT