Systems containing software fail, and the cause of that failure may originate in software.

And the article you intended to link is just wrong. E.g. the Therac-25 was not designed to output high power when an operator typed quickly; it was built in such a way to do so. This would be analogous to describing an airplane failure due to using bolts that were too weak: "the bolt didn't fail; it broke under exactly the forces you would expect it to break from its size; if they wanted it to not break, they should have used a larger bolt!" Just like in the Therac example, the failure would be consistently reproducible.

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kqr 4 days ago | parent | next [-]

It sounds like our main disagreement lies around whether to call it "design error" or "build error" but I do not believe this erases the useful distinction between "error present in the thing from day one" and "unpredictable failure of component suddenly no longer doing what it used to do".

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aidenn0 3 days ago | parent [-]

I think that's definitely part of it. I also believe that a physical component put under stresses it was not capable of bearing, even when those stresses were known to be within the expected environment at design time -- such as a bolt that was too weak for expected conditions -- is both:

1. Generally referred to as a "failure" of the part

2. Closely analogous to many software defects that cause system failure.

	▲	kqr 2 days ago \| parent [-]
		> Generally referred to Sure, people may sloppily call it a failure, but then they miss out on a useful distinction which would help them create more robust software. A bolt being under-engineered for its intended usage is a design error. When it breaks, that's a predictable (but unfortunate) mode of operation of the design, not a failure. (It has inadvertently been designed to act as a frangible link.) The reason it's important to distinguish between the two cases is that we use different methods to deal with them.

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motxilo 4 days ago | parent | prev [-]

You allude to the difference between requirements and constraints. What you say is true, but also it's true that the Therac-25 was not designed to not output high power when an operator typed quickly.