[maweki]

I teach the horizon post office scandal in my database courses. And my takeaway is, that software fails. And if people's lives are involved, an audit trail is paramount.

In slowly killing software the audit trail might be faster than the killing. In fast killing software, the audit trail isn't.

[SCdF]

Yes, the audit trail that should exist is part of the package. Or more generically, Horizon should have had enough instrumentation, combined with adequate robustness, where they could detect the issues the lack of robustness caused, and resolve those issues without people dying.

My core point is that if you're designing a system, *any system*, you should be thinking about what is required to produce safe software. It isn't just "well I don't work on medical devices that shoot radiation at people, so I don't need to worry"[1]. You still need to worry, you just solve those problems in different ways. It's not just deaths either, it's PII leakage, it's stalking and harassment enablement, it's privilege escalation, etc.

[1] I have heard this, or a variation of this, from dozens of people over the my career. This is my core bug bear about Therac-25, is that it allows people to think this way, and divest themselves of responsibility. I am very happy to hear you are teaching a course about Horizon, because it's a much more grounded example that devs will hopefully see themselves in more. If your course is publicly available btw, I'd love to read it.

[maweki]

It's just a course about database design and in the first seminar we look at different news stories that have something to do with databases, like trump putting some random Italian chef on an international sanction list should make us think about primary keys and identifying people.

And the horizon post office scandal is the last and most poignant example that real people are affected by the systems we build and the design decisions we make. That sometimes easy to forget.