On 20/04/2019 18:10, Enrico Nardelli wrote:
Mi sembra interessante sottolineare anche questi passaggi dell'articolo
----- The 737 Max saga teaches us not only about the limits of technology and the risks of complexity, it teaches us about our real priorities. Today, safety doesn’t come first — money comes first, and safety’s only utility in that regard is in helping to keep the money coming. The problem is getting worse because our devices are increasingly dominated by something that’s all too easy to manipulate: software.
a me sembra che "sopravvivenza comes first". non credo che i margini di boeing ed airbus siano radicalemente diversi (non ho controllato). boeing pare aver cercato la strada breve del sw (compromettendo la sicurezza) per poter rimanere competitiva nei confronti di airbus che (apparentemente) questi problemi di sicurezza non ha. se boeing avesse dovuto rifare tutto il processo come un velivolo nuovo, sarebbe stata fuori mercato e quindi (probabilmente) morta...
... Software defects, on the other hand, are easy and cheap to fix. All you need to do is post an update and push out a patch. What’s more, we’ve trained consumers to consider this normal, whether it’s an update to my desktop operating systems or the patches that get posted automatically to my Tesla while I sleep. ... I believe the relative ease — not to mention the lack of tangible cost — of software updates has created a cultural laziness within the software engineering community. -----
Il 19/04/2019 09:02, Alberto Cammozzo ha scritto:
Come accade che 346 persone muoiano di software.
<https://spectrum.ieee.org/aerospace/aviation/how-the-boeing-737-max-disaster...>
[...] It is astounding that no one who wrote the MCAS software for the 737 Max seems even to have raised the possibility of using multiple inputs, including the opposite angle-of-attack sensor, in the computer’s determination of an impending stall. As a lifetime member of the software development fraternity, I don’t know what toxic combination of inexperience, hubris, or lack of cultural understanding led to this mistake.
But I do know that it’s indicative of a much deeper problem. The people who wrote the code for the original MCAS system were obviously terribly far out of their league and did not know it. How can they can implement a software fix, much less give us any comfort that the rest of the flight management software is reliable?
So Boeing produced a dynamically unstable airframe, the 737 Max. That is big strike No. 1. Boeing then tried to mask the 737’s dynamic instability with a software system. Big strike No. 2. Finally, the software relied on systems known for their propensity to fail (angle-of-attack indicators) and did not appear to include even rudimentary provisions to cross-check the outputs of the angle-of-attack sensor against other sensors, or even the other angle-of-attack sensor. Big strike No. 3.
None of the above should have passed muster. None of the above should have passed the “OK” pencil of the most junior engineering staff, much less a DER.
That’s not a big strike. That’s a political, social, economic, and technical sin. [...]
It is likely that MCAS, originally added in the spirit of increasing safety, has now killed more people than it could have ever saved. It doesn’t need to be “fixed” with more complexity, more software. It needs to be removed altogether.
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===================================================================== Prof. Enrico Nardelli Dipartimento di Matematica - Universita' di Roma "Tor Vergata" Via della Ricerca Scientifica snc - 00133 Roma tel: +39 06 7259.4204 fax: +39 06 7259.4699 mobile: +39 335 590.2331 e-mail: nardelli@mat.uniroma2.it home page: http://www.mat.uniroma2.it/~nardelli blog: http://www.ilfattoquotidiano.it/blog/enardelli/ http://link-and-think.blogspot.it/ =====================================================================
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