[elfchief]

IIRC, they did identify a bit that if it were flipped in a certain way at a certain time, would lead to the struck throttle condition, and were able to successfully replicate the stuck throttle condition by 'manually' flipping that bit. So they never reproduced the problem in the field, but they could force a condition that would cause it -- and for a one-in-a-million thing like a cosmic ray bit flip, that seems like a reasonable methodology.

(and was only a problem because they didn't handle critical variables correctly, by having mirrors of the values that could be compared to protect against various types of corruption)

[buescher]

Koopman is the real deal. Big fan of the RTX-2000 here, and his embedded software book is excellent. But my recollection is that he and Barr found no such particular bit - the argument was, if one task failed, which could be due to any number of potential bugs, perhaps just one bit getting flipped, the unintended acceleration could happen.

The material from Barr is worth reading too (google it), and if you want some amusement:

https://www.embedded.com/why-every-embedded-software-develop...

https://www.embedded.com/a-rebuttal-to-why-every-embedded-so...