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The Therac-25 Incident (2021)

(thedailywtf.com)
449 points lemper | 3 comments | 27 Aug 25 06:57 UTC | HN request time: 0.689s | source
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benrutter ◴[27 Aug 25 08:18 UTC] No.45036836[source]▶
> software quality doesn't appear because you have good developers. It's the end result of a process, and that process informs both your software development practices, but also your testing. Your management. Even your sales and servicing.

If you only take one thing away from this article, it should be this one! The Therac-25 incident is a horrifying and important part of software history, it's really easy to think type-systems, unit-testing and defensive-coding can solve all software problems. They definitely can help a lot, but the real failure in the story of the Therac-25 from my understanding, is that it took far too long for incidents to be reported, investigated and fixed.

There was a great Cautionary Tales podcast about the device recently[0], one thing mentioned was that, even aside from the catasrophic accidents, Therac-25 machines were routinely seen by users to show unexplained errors, but these issues never made it to the desk of someone who might fix it.

[0] https://timharford.com/2025/07/cautionary-tales-captain-kirk...

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1. rowanG077 ◴[28 Aug 25 00:32 UTC] No.45046969[source]▶
I think the opposite. The only reason software quality emerges is because of good developers. It's a prerequisites. Process helps good developers deliver quality. But there is no process that allows a team of bad developers deliver quality. you can't squeeze blood from a stone.
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2. benrutter ◴[28 Aug 25 09:29 UTC] No.45050179[source]▶
That's true, but even so - great developers still make mistakes, and if they don't hear about production errors because of a breakdown in the customer communications from sales etc, then those mistakes will never be fixed.

It's not that great developers aren't necessary for software quality, more that they aren't sufficient.

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3. rowanG077 ◴[29 Aug 25 08:10 UTC] No.45061480[source]▶
I think great developers are necessary for software quality. But indeed often not sufficient.