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How NASA built Artemis II’s fault-tolerant computer

cacm.acm.org

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

#71

Post by MikeTheGreat »

vasco wrote: post #60
dmk wrote: post #3

The quote from the CMU guy about modern Agile and DevOps approaches challenging architectural discipline is a nice way of saying most of us have completely forgotten how to build deterministic systems. Time-triggered Ethernet with strict frame scheduling feels like it's from a parallel universe compared to how we ship software now.

It's not like the approach they took is any different. Just slapped 8x the number of computers on it for calculating the same thing and wait to see if they disagree. Not the pinnacle of engineering. The equivalent of throwing money at the problem.

What happens when they don't?

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

#72

Post by vasco »

MikeTheGreat wrote: post #71
vasco wrote: post #60

Earlier quoted context omitted.

It's not like the approach they took is any different. Just slapped 8x the number of computers on it for calculating the same thing and wait to see if they disagree. Not the pinnacle of engineering. The equivalent of throwing money at the problem.

What happens when they don't?

If you have a point to make, make it.

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

#74

Post by therobots927 »

carefree-bob wrote: post #66
dmk wrote: post #3

The quote from the CMU guy about modern Agile and DevOps approaches challenging architectural discipline is a nice way of saying most of us have completely forgotten how to build deterministic systems. Time-triggered Ethernet with strict frame scheduling feels like it's from a parallel universe compared to how we ship software now.

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.

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

#75

Post by vhiremath4 »

> “Along with physically redundant wires, we have logically redundant network planes. We have redundant flight computers. All this is in place to cover for a hardware failure.”

It would be really cool to see a visualization of redundancy measures/utilization over the course of the trip to get a more tangible feel for its importance. I'm hoping a bunch of interesting data is made public after this mission!

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

#76

Post by therobots927 »

ramraj07 wrote: post #6
dmk wrote: post #3

The quote from the CMU guy about modern Agile and DevOps approaches challenging architectural discipline is a nice way of saying most of us have completely forgotten how to build deterministic systems. Time-triggered Ethernet with strict frame scheduling feels like it's from a parallel universe compared to how we ship software now.

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.

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

#77

Post by buster »

dyauspitr wrote: post #54
dmk wrote: post #3

The quote from the CMU guy about modern Agile and DevOps approaches challenging architectural discipline is a nice way of saying most of us have completely forgotten how to build deterministic systems. Time-triggered Ethernet with strict frame scheduling feels like it's from a parallel universe compared to how we ship software now.

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.

You hopefully know thats not true. But it's a matter of quality goals. Need absolute robustness? Prioritize it and build it. Need speed and be first to market? Prioritize and build it. You can do both in an agile way. Many would argue that you won't be as fast in a non-agile way. There is no bullet point in the agile manifest saying to build unreliable software.

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

#78

Post by therobots927 »

y1n0 wrote: post #16

NASA didn't build this, Lockheed Martin and their subcontractors did. Articles and headlines like this make people think that NASA does a lot more than they actually do. This is like a CEO claiming credit for everything a company does.

[flagged]

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

#80

Post by pjmlp »

dmk wrote: post #3

The quote from the CMU guy about modern Agile and DevOps approaches challenging architectural discipline is a nice way of saying most of us have completely forgotten how to build deterministic systems. Time-triggered Ethernet with strict frame scheduling feels like it's from a parallel universe compared to how we ship software now.

As 70's child that was there when the whole agile took over, and systems engineer got rebranded as devops, I fully agree with them.

Add TDD, XP and mob programming as well.

While in some ways better than pure waterfall, most companies never adopted them fully, while in some scenarios they are more fit to a Silicon Valley TV show than anything else.

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