Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How NASA built Artemis II’s fault-tolerant computer

cacm.acm.org

Post reply on HN
Print view View original

121–130 of 257 posts

Re: How NASA built Artemis II’s fault-tolerant computer

#121

Post by childintime »

therobots927 wrote: post #76
ramraj07 wrote: post #6

Earlier quoted context omitted.

I take the opposite message from that line - out of touch teams working on something so over budget and so overdue, and so bureaucratic, and with such an insanely poor history of success, and they talk as if they have cured cancer. This is the equivalent of Altavista touting how amazing their custom server racks are when Google just starts up on a rack of naked motherboards and eats their lunch and then the world. Le…

Modern software development is a fucking joke. I’m sorry if that offends you. Somehow despite Moore’s law, the industry has figured out how to actually regress on quality.

Lately it strikes me there's a big gap between the value promised and the value actually delivered, compared to a simple home grown solutions (with a generic tool like a text editor or a spreadsheet, for example). If they'd just show how to fish, we wouldn't be buying, the magic would be gone.

In this sense all of the West is full of shit, and it's a requirement. The intent is not to help and make life better for everyone, cooperate, it is to deceive and impoverish those that need our help. Because we pity ourselves, and feed the coward within, that one that never took his first option and chose to do what was asked of him instead.

This is what our society deviates us from, in its wish to be the GOAT, and control. It results in the production of lives full of fake achievements, the constant highs which i see muslims actively opt out of. So they must be doing something right.

Re: How NASA built Artemis II’s fault-tolerant computer

#122

Post by g6pdh »

nickff wrote: post #57
dyauspitr wrote: post #54

Earlier quoted context omitted.

Agile is not meant to make solid, robust products. It’s so you can make product fragments/iterations quickly, with okay quality and out to the customer asap to maximize profits.

“Agile” doesn’t mean that you release the first iteration, it’s just a methodology that emphasizes short iteration loops. You can definitely develop reliable real-time systems with Agile.

A physicist who worked on radiation-tolerant electronics here. Apart from the short iteration loops, agile also means that the SW/HW requirements are not fully defined during the first iterations, because they may also evolve over time. But this cannot be applied to projects where radiation/fault tolerance is the top priority. Most of the time, the requirements are 100% defined ahead of time, leading to a waterfall-like or a mixed one, where the development is still agile but the requirements are never discussed again, except in negligible terms.

Re: How NASA built Artemis II’s fault-tolerant computer

#123

Post by zeristor »

tux wrote: post #69
SeanAnderson wrote: post #67

Typo in the first sentence of the first paragraph is oddly comforting since AI wouldn't make such a typo, heh. Typo in the first sentence of the second paragraph is sad though. C'mon, proofread a little.

I think everyone should now make mistakes so we ca distinguish human vs ai.

This can be optimised for no doubt, adversarial training is like that

Re: How NASA built Artemis II’s fault-tolerant computer

#125

Post by nairboon »

therobots927 wrote: post #74
carefree-bob wrote: post #66

Earlier quoted context omitted.

During the time of the first Apollo missions, a dominant portion of computing research was funded by the defense department and related arms of government, making this type of deterministic and WCET (worst case execution time) a dominant computing paradigm. Now that we have a huge free market for things like online shopping and social media, this is a bit of a neglected field and suffers from poor investment and mind…

Contrary to propaganda from the likes of Ludwig von Mises, the free market is not some kind of optimal solution to all of our problems. And it certainly does not produce excellent software.

Propaganda is quite a strong term to describe the works of an economist. If one wants to debate the ideas of von Mises, it'd be useful to consider the Zeitgeist at that time. Von Mises preferred free markets in contrast to the planned economy of the communists. Partly because the latter has difficulties in proper resource allocation and pricing. Note that this was decades before we had working digital computers and digital communication systems, which, at least in theory, change the feasibility of a planned economy.

Also, the last time I checked, the US government produced its goods and services using the free market. The government contractors (private enterprises) are usually tasked with building stuff, compared with the government itself in a non-free, purely planned economy (if you refer to von Mises).

I assume that you originally meant to refer to the idea that without government intervention (funding for deep R&D), the free market itself would probably not have produced things like the internet or the moon landing (or at least not within the observed time span). That is, however,a rather interesting idea.

Re: How NASA built Artemis II’s fault-tolerant computer

#126

Post by BitsAndObjects »

BitsAndObjects wrote: post #21
jbritton wrote: post #12

I wonder how often problems happen that the redundancy solves. Is radiation actually flipping bits and at what frequency. Can a sun flare cause all the computers to go haywire.

Not a direct answer but probably as good information as you can get: https://static.googleusercontent.com/media/research.google.c... Basically, yes, radiation does cause bit flips, more often than you might expect (but still a rare event in the grand scheme of things, but enough to matter). And radiation in space is much “worse” (in quotes because that word is glossing over a huge number of different problems, both j…

Typo: “both” ~ “not”

Re: How NASA built Artemis II’s fault-tolerant computer

#127

Post by BitsAndObjects »

gambiting wrote: post #118

So honest and perhaps a bit stupid question. Astronauts have actual phones with them - iPhones 17 I think? And a regular Thinkpad that they use to upload photos from the cameras. How does all of that equipment work fine with all the cosmic radiation floating about? With the iPhone's CPU in particular, shouldn't random bit flips be causing constant crashes due to errors? Or is it simply that these errors happen but no…

They’re not mission-critical equipment. If they fail, nobody dies.

They’re not radiation hardened, so given enough time, they’d be expected to fail. Rebooting them might clear the issue or it might not (soft vs hard faults).

Also impossible to predict when a failure would happen, but NASA, ESA and others have data somewhere that makes them believe the risk is high enough that mission critical systems need this level of redundancy.

Re: How NASA built Artemis II’s fault-tolerant computer

#129

Post by lelanthran »

InsideOutSanta wrote: post #117
ramraj07 wrote: post #31

Earlier quoted context omitted.

[flagged]

Can't tell if "arrogant nasal engineers" is a typo or a hilarious attempt at an insult.

Nasal demons is a common reference to C and C++ Undefined Behaviour.

When an AI codes for you, you get Undefined Behaviour in every language.

Re: How NASA built Artemis II’s fault-tolerant computer

#130

Post by weli »

therobots927 wrote: post #74
carefree-bob wrote: post #66

Earlier quoted context omitted.

During the time of the first Apollo missions, a dominant portion of computing research was funded by the defense department and related arms of government, making this type of deterministic and WCET (worst case execution time) a dominant computing paradigm. Now that we have a huge free market for things like online shopping and social media, this is a bit of a neglected field and suffers from poor investment and mind…

Contrary to propaganda from the likes of Ludwig von Mises, the free market is not some kind of optimal solution to all of our problems. And it certainly does not produce excellent software.

Mises never claimed that the free market produced the most optimal solutions at a given moment. In fact Mises explicitly stated many times that the free market does indeed incur in semi-frequent self-corrections, speculations and manipulations by the agents.

What Mises proposition was - in essence - is that an autonomous market with enough agents participating in it will reach an optimal Nash equilibrium where both offer and demand are balanced. Only an external disruption (interventionism, new technologies, production methods, influx or efflux of agents in the market) can break the Nash equilibrium momentarily and that leads to either the offer or the demand being favored.

Post reply on HN