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Watchdog

The watchdog is used to automatically reset the system when it becomes unresponsive. Once enabled, you must write to it again within 16 seconds (i.e., pet the dog); otherwise, the system will reboot.

Enable: Writing any character except the capital letter V will enable the watchdog. You must write to it again within 16 seconds.

echo A > /dev/watchdog

Disable: Write the capital letter V to stop the watchdog.

echo V > /dev/watchdog

Test approach:

1. Enable the watchdog but do not pet it. Wait 16 seconds — the system should automatically reboot. 2. Enable the watchdog and pet it repeatedly in a loop. The system should continue running normally.