THE TRAGIC RACE CONDITION

Summary from the TLDR Web Dev newsletter

The Therac-25, a radiation therapy machine, suffered from a software flaw that led to fatal radiation overdoses for multiple patients. The machine's software contained a race condition – safety settings would be ignored if operators entered commands too quickly in a specific sequence, leading to massive radiation doses. Between 1985 and 1987, at least six patients received lethal levels of radiation, causing severe injuries, disability, and death. The disasters stemmed from multiple failures, such as poor software development practices, inadequate testing, overconfidence in the system's safety, and a lack of regulatory oversight.