Binary package “watchdog” in ubuntu lucid

A software watchdog

 The watchdog program writes to /dev/watchdog every ten seconds. If
 the device is opened but not written to within a minute, the machine
 will reboot. This feature is available when the kernel is built with
 'software watchdog' support (standard in Debian kernels).
 .
 The ability to reboot will depend on the state of the machine
 and interrupts.