Watchdog

   Watchdog is a special [1]timer that serves as a safety mechanism for
   detecting malfunction of computer programs at [2]run time by requiring
   programs to periodically reset the timer.

   Basically watchdog keeps counting up and a correctly behaving program is
   supposed to periodically reset this count ("kick" or "feed the dog") -- if
   the reset doesn't happen for a longer period, the watchdog counts up to a
   high value and alerts that something's wrong ("the dog starts barking"),
   e.g. with an [3]interrupt or a [4]signal. This can mean for example that
   the program has become stuck in an [5]infinite loop or that its
   instructions were corrupted and the program control jumped to some
   unintended area of RAM and is doing crazy [6]shit. This is usually handled
   by resetting the system so as to prevent possible damage by the program
   gone insane, also [7]logs can be made etc. Watchdogs are very often used
   in [8]embedded systems. [9]Operating systems may also use them to detect
   nonresponsive [10]processes.

   Watchdog is similar to the dead man's switch used e.g. in trains where the
   operator is required to periodically push a button otherwise the train
   will automatically activate brakes as the operator is probably sleeping or
   dead.

See Also

     * [11]dog

Links:
1. timer.md
2. run_time.md
3. interrupt.md
4. signal.md
5. infinite_loop.md
6. shit.md
7. log.md
8. embedded.md
9. os.md
10. process.md
11. dog.md