Okay, I think that's an unhelpful way to put it, but it's still worth addressing, and there's a lot to unpack here, so here goes.

My original point was that flight critical software shouldn't be lumped in with the bugs-typical world of software. I still say that's correct.

But "bug" has a range of meanings. From what I read of the story of the original fatal error on the 300 MAX, the software was not buggy in the sense of "deviating from specification". It's just that -- as it turns out -- the specification was bad, and the MCAS should not have overridden pilot input when it did.

In a sense -- the one I consider most important -- that matches my model of flight-critical software. As software, they made absolutely sure that, in every case, it did what it was intended to; to the extent that it was in error, it was not in the sense of "we failed to make the software do what the spec says".

OTOH, I agree that "bug" is taken more broadly in software than the sense I was using here, that there usually isn't such a clean ("Waterfall") separation between "specifying what the software should do" and "ensuring that it does that" -- there's a collaborative process of ferreting out the implications of "what the system should do at what points".

In these latest events, it looks like the bug was in the narrower sense I meant above, of "it doesn't meet the spec", and that bug was found before deaths. From the article:

>The problem was that an indicator light, designed to warn of a malfunction by a system that helps raise and lower the plane’s nose, was turning on when it wasn’t supposed to, the company said.

Now, in fairness, that's a much later discovery than my optimistic model held, but still far earlier than "being used for flying the public around", as (the analog of) might happen with the software industry more generally.