

Margaret Hamilton, the Engineer Who Took the Apollo to the Moon - hownottowrite
https://medium.com/@verne/margaret-hamilton-the-engineer-who-took-the-apollo-to-the-moon-7d550c73d3fa

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jakub_h
Uh. There's so much wrong in that article that it hurts. Can't people actually
research history more seriously?

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GFK_of_xmaspast
Such as?

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jakub_h
Have you read _Digital Apollo_ by Dave Mindell? If not, do so. It is a much
better researched text on the story of Apollo guidance, by a professor of
aerospace history who works at the institution (MIT) formerly involved with
AGC. In the meanwhile, the text at
[http://www.doneyles.com/LM/Tales.html](http://www.doneyles.com/LM/Tales.html)
will de-disinform you with regards to some of the article's mistakes.

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GFK_of_xmaspast
I just skimmed that but I don't see anything there that would contradict the
original post.

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jakub_h
What about the claim about the actual cause of the Apollo 11 program alarms?
What about the involvement of Hal Laning in the actual design and
implementation of the real-time executive casually attributed to Hamilton in
this article and some of the others on the web?

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GFK_of_xmaspast
They both appear to claim that the alarms were caused by too-heavy processing
loads: " This was the action taken by the Executive program if its resources
were exceeded. If a job could not be scheduled because no "core sets" were
available, the Executive called BAILOUT with alarm code 1202. If no "VAC
areas" were available, BAILOUT was called with alarm code 1201."

vs "The result was that the computer was being asked to perform all of its
normal functions for landing while receiving an extra load of spurious data
which used up 15% of its time. The computer (or rather the software in it) was
smart enough to recognize that it was being asked to perform more tasks than
it should be performing. It then sent out an alarm, which meant to the
astronaut, “I’m overloaded with more tasks than I should be doing at this time
and I’m going to keep only the more important tasks; i.e., the ones needed for
landing.” "

Hamilton claimed in 1971 that "Due to an error in the checklist manual, the
rendezvous radar switch was placed in the wrong position", Eyles says "The
problem has also been attributed (including by the author previously) to a
"checklist error".

Also if you're going to point out that the Medium article doesn't mention
Laning, it seems equally damming that Eyles doesn't mention Hamilton.

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jakub_h
I was talking about the root cause, not about the symptoms. The article claims
that the alarms were caused by a "checklist error", when in reality, it was an
analog interface mismatch caused by incomplete specification which two
different teams interpreted sufficiently differently to cause a hard-to-debug
hardware problem.

If Eyles doesn't mention Hamilton, it's probably because she wasn't involved
in the particular functionality of the Apollo software that is being ascribed
to her by many articles on the Internet and that is relevant to the Apollo 11
incident. In this particular article, it's not claimed explicitly by the
author, but it is insinuated by the statement "I read that the Apollo would
not have been able to land without your software." Well, of course, if she was
a team lead on the software effort, the whole software is "hers" from a
certain point of view, but that's sort of like giving whole credit to Bill
Gates for writing Microsoft Windows. Mindell does mention her on several
occasions, but in the software resilience area, he connects her to rigorous
checking and prevention of erroneous user inputs, not to executive fault-
tolerance. This functionality has proven critical on at least one occasion
(when Apollo 8 astronauts mistakenly attempted to initiate pre-start sequence
in mid-flight) but not in the incident in question.

