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Vision: Zero Bugs — Johann Schleier-Smith, Temporal
Takeaway
Aerospace shows zero-bug software is possible with N-version, formal-method, and process-driven engineering — a discipline AI-generated code increasingly needs.
Summary
- Johann Schleier-Smith (Temporal) argues 'zero bugs' is achievable — the Airbus A320 has zero serious software-attributed incidents since the 1980s.
- A320 techniques: N-version programming on different CPUs/OSes/teams, specification-based design, independent verification, no runtime allocation, static analysis.
- Space Shuttle last 3 versions had ~1 error per 420K-line version — ~1000x fewer bugs per line than typical commercial code.
- Mindset is 'zero defect tolerance' treating software as a certified component, with system-level reliability thinking borrowed from mechanical engineering.
- Frames a path for AI-era 'quality through process' so agentic coding can keep agents on rails as software increasingly interfaces with the physical world.
reliabilityverificationtemporal
Original description
Software with zero bugs sounds absurd, or even impossible, in anything but simple situations, but it has been built. For example, NASA's Space Shuttle software achieved near-perfection (1 error per 420,000 lines) using rigorous engineering practices. This feat was achieved decades ago, yet cost prevented the techniques used from becoming mainstream. This talk traces seventy years of innovation in software quality and programmer productivity, ranging from structured programming to formal verification. While many of these techniques have been too costly to implement on a large scale, AI changes that. What is more, agentic coding needs them to compensate for its limitations. We are on the verge of a world where aerospace-level reliability becomes the practical in a broad range of applications. Johann Schleier-Smith is Technical Lead for AI at Temporal Technologies, the leading provider of durable execution. He previously founded Crystal DBA, which developed agents to manage cloud infrastructure and was acquired by Temporal. He also co-founded if(we), which built a collection of social networks with over 300 million members and was acquired by The Meet Group (NASDAQ:MEET). Johann serves on the board of Sama, a leading provider of training data for computer vision applications. He holds a Ph.D. in Computer Science from UC Berkeley and an A.B. in Physics and Mathematics from Harvard University. --- Socials: - LinkedIn: https://www.linkedin.com/in/jssmith/ - X (Twitter): https://x.com/jssmith - GitHub: https://github.com/jssmith - Website: https://johann.schleier-smith.com/ - Company: Temporal Technologies (https://temporal.io/)