We found an undocumented bug in the Apollo 11 guidance computer code • Hacker News Board

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#71

Post by caminante » Tue, Apr 07, 2026, 1:17 PM UTC

Qwuke wrote: post #67

throwaway27448 wrote: post #51

Earlier quoted context omitted.

It's not even clear if AI was used to find the bug: they mention modeling the software with an "ai native" language, whatever that means. What is not clear is how they found themselves modeling the gyros software of the apollo code to begin with. But, I do think their explanation of the lock acquisition and the failure scenario is quite clear and compelling.

>It's not even clear if AI was used to find the bug It's not even clear you read the article

Even worse, the other child comments are speculating (and didn't RTFA either) when the answer is clear in the article.

> We found this defect by distilling a behavioural specification of the IMU subsystem using Allium, an AI-native behavioural specification language.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#72

Post by xmcqdpt2 » Tue, Apr 07, 2026, 1:18 PM UTC

monooso wrote: post #27

croemer wrote: post #16

Earlier quoted context omitted.

These are just some of the good examples I found. My hunch that this is substantially LLM-generated is based on more than that. In my head it's like a Bayesian classifier, you look at all the sentences and judge whether each is more or less likely to be LLM vs human generated. Then you add prior information like that the author did the research using Claude - which increases the likelihood that they also use Claude f…

Here's an alternative way of thinking about this... Someone probably expended a lot of time and effort planning, thinking about, and writing an interesting article, and then you stroll by and casually accuse them of being a bone idle cheat, with no supporting evidence other than your "sensitive detector" and a bunch of hand-wavy nonsense that adds up to naught.

To start, this is more or less an advertising piece for their product. It's pretty clear that they want to sell you Allium. And that's fine! They are allowed! But even if that was written by a human, they were compensated for it. They didn't expend lots of effort and thinking, it's their job.

More importantly, it's an article about using Claude from a company about using Claude. I think on the balance it's very likely that they would use Claude to write their technical blog posts.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#73

Post by buredoranna » Tue, Apr 07, 2026, 1:20 PM UTC

Still my all time favorite snippet of code.

    TC    BANKCALL    # TEMPORARY, I HOPE HOPE HOPE
    CADR  STOPRATE    # TEMPORARY, I HOPE HOPE HOPE
    TC    DOWNFLAG    # PERMIT X-AXIS OVERRIDE

https://github.com/chrislgarry/Apollo-11/blob/master/Luminar...

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#74

Post by bakugo » Tue, Apr 07, 2026, 1:21 PM UTC

brookst wrote: post #63

Gigachad wrote: post #57

Earlier quoted context omitted.

HN has gotten to the point where it’s not even worth clicking the link because of course it’s ai slop. There is some real content in the haystack, but we almost need some kind of curator to find and display it rather than a vote system where most people vote on the title alone.

If you’re looking for a place that surfaces only human-written content regardless of whether it’s interesting, rather than interesting content regardless of how it was written, HN is not the place. There might be a market for your alternative though. Should be easy enough to build with Claude Code.

If the content was interesting, the author would've written about it himself.

By asking AI to write the article for you, you're asserting that the subject matter is not interesting enough to be worth your time to write, so why would it be worth my time to read?

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#75

Post by embedding-shape » Tue, Apr 07, 2026, 1:21 PM UTC

xmcqdpt2 wrote: post #64

embedding-shape wrote: post #35

Earlier quoted context omitted.

> because that article is full of Claude-isms Not sure how I feel about the whole "LLMs learned from human texts, so now the people who helped write human texts are suddenly accused of plagiarizing LLMs" thing yet, but seems backwards so far and like a low quality criticism.

I'm sure some human writers would write: > The specification forces this question on every path through the IMU mode-switching code. A reviewer examining BADEND would see correct, complete cleanup for every resource BADEND was designed to handle. > The specification approaches from the other direction: starting from LGYRO and asking whether any paths fail to clear it. > *Tests verify the code as written; a behavioura…

> Do you really think they spent the time required to actually write a good article by hand?

Given I'm familiar with Juxt since before, used plenty of their Clojure libraries in the past and hanged out with people from Juxt even before LLMs were a thing, yes, I do think they could have spent the time required to both research and write articles like these. Again, won't claim for sure I know how they wrote this specific article, but I'm familiar with Juxt enough to feel relatively confident they could write it.

Juxt is more of a consultancy shop than "AI company", not sure where you got that from, guess their landing page isn't 100% clear what they actually does, but they're at least prominent in the Clojure ecosystem and has been for a decade if not more.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#76

Post by monooso » Tue, Apr 07, 2026, 1:22 PM UTC

xmcqdpt2 wrote: post #72

monooso wrote: post #27

Earlier quoted context omitted.

Here's an alternative way of thinking about this... Someone probably expended a lot of time and effort planning, thinking about, and writing an interesting article, and then you stroll by and casually accuse them of being a bone idle cheat, with no supporting evidence other than your "sensitive detector" and a bunch of hand-wavy nonsense that adds up to naught.

To start, this is more or less an advertising piece for their product. It's pretty clear that they want to sell you Allium. And that's fine! They are allowed! But even if that was written by a human, they were compensated for it. They didn't expend lots of effort and thinking, it's their job. More importantly, it's an article about using Claude from a company about using Claude. I think on the balance it's very likel…

> They didn't expend lots of effort and thinking, it's their job.

Your job doesn't require you to think or expend effort?

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#77

Post by pooloo » Tue, Apr 07, 2026, 1:23 PM UTC

whiplash451 wrote: post #52

riverforest wrote: post #42

Software that ran on 4KB of memory and got humans to the moon still has undiscovered bugs in it. That says something about the complexity hiding in even the smallest codebases.

My guess is that in such low memory regimes, program length is very loosely correlated with bug rate. If anything, if you try to cram a ton of complexity into a few kb of memory, the likelihood of introducing bugs becomes very high.

Yet here we are compounding the issues by adding more and more layers to these systems... The higher the level it becomes the more security risks we take.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#78

Post by d1sxeyes » Tue, Apr 07, 2026, 1:24 PM UTC

360MustangScope wrote: post #15

monooso wrote: post #11

Earlier quoted context omitted.

That's just writing. I frequently write like that. This insistence that certain stylistics patterns are "tell-tale" signs that an article was written by AI makes no sense, particularly when you consider that whatever stylistic ticks an LLM may possess are a result of it being trained on human writing.

I hate that I can’t write em dashes freely anymore without people accusing the writing of being AI generated. Even though they are perfect for usage in writing down thoughts and notes.

One thing you can try⸺admittedly it's not quite correct⸺is replacing them with a two-em dash. I've never seen an AI use one, and it looks pretty funky.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#79

Post by Gigachad » Tue, Apr 07, 2026, 1:25 PM UTC

bakugo wrote: post #74

brookst wrote: post #63

Earlier quoted context omitted.

If you’re looking for a place that surfaces only human-written content regardless of whether it’s interesting, rather than interesting content regardless of how it was written, HN is not the place. There might be a market for your alternative though. Should be easy enough to build with Claude Code.

If the content was interesting, the author would've written about it himself. By asking AI to write the article for you, you're asserting that the subject matter is not interesting enough to be worth your time to write, so why would it be worth my time to read?

You just need AI to read it for you and summarise back in to the original prompt.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#80

Post by perching_aix » Tue, Apr 07, 2026, 1:27 PM UTC

chrisjj wrote: post #65

> The specs were derived from the code itself Oh dear. I strongly suggest this author look specification up in a dictionary.

It's (what they're describing is) just reverse engineering. That's what reverse engineering is.