The Therac-25: Software that Kills
Two keystrokes too fast. A status message no one understood: “Malfunction 54.” And in seconds, a patient received a lethal radiation dose. The Therac-25 wasn’t science fiction—it was a real medical device whose software failures caused at least six massive overdoses between 1985 and 1987.
This talk dissects the exact engineering mistakes that let a race condition, cryptic UX, and misplaced trust in software-only “interlocks” turn life-saving equipment into a weapon—and translates them into hard, modern lessons you can apply today. We’ll walk through how concurrency bugs slipped past testing, how reused code and optimistic assumptions compounded risk, why safety must be layered (not just “handled in software”), and how to design alarms, logs, and operator workflows that actually prevent harm.
About the speaker
Kyle Kotowick
Dr. Kyle Kotowick is the founder of a Canadian consulting and development firm focusing on cloud infrastructure, security, and Internet-of-Things implementations for high-growth clients. He completed his Ph.D. in MIT's Computer Science and Artificial Intelligence Laboratory, joint with the Department of Aeronautics and Astronautics. He has served as a consultant, systems architect, and developer for global firms, startups, and universities; as a project lead for military medical and communication technology; and as a researcher for military navigation systems and for life support systems in space. He specializes in working with both startups and enterprise clients to define requirements and explore possible solutions, as well as in leading the development of project architecture, cloud services, and back-end software.