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Original Apollo 11 Guidance Computer source code for command and lunar modules

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Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#23

Post by mb_thd »

mittermayr wrote: post #21

Well, I have no idea how complete this is, but perhaps a neat Christmas-time-project for anyone with seemingly unlimited tokens to take this and let it build up a simulator, using the real code to drive simulated machinery.

Or you use the virtualagc project linked in the readme to do the same thing without wasting a bunch of money on tokens.

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#26

Post by detourdog »

corvad wrote: post #3

Really cool to see this digitized and archived, it's such an important piece of history and really one of the earliest digital ic bases computers.

I have been collecting Autonetics artifacts off ebay for decades. What I find interesting about this time period is that Autonetics made 3 different efforts for digital inertial guidance. The first version used vacuum tubes and was never commpleted. The second version used the new discrete components developed by Sprague Electric. This version went into production. Autonetics then set about exploring the lithographic process to shrink the discrete component version into an IC based system. Autonetics essentially built the same computer using 3 different circuit construction methods. Here are some pictures of pieces of all 3 systems. The IC's are from about 1967.

One of the 2 nerds in the photo is Richard Stallman next to the Autonetics D-17B. An early inertial guidance system distributed to universities to study as real time computers after decommissioning.

There are also the hard disks(which the D-17B used as a clock) and gyroscopes that served as inputs.

https://www.icloud.com/sharedalbum/#B1iG4TcsmGWIVSf

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#27

Post by dessimus »

mb_thd wrote: post #23
mittermayr wrote: post #21

Well, I have no idea how complete this is, but perhaps a neat Christmas-time-project for anyone with seemingly unlimited tokens to take this and let it build up a simulator, using the real code to drive simulated machinery.

Or you use the virtualagc project linked in the readme to do the same thing without wasting a bunch of money on tokens.

And miss the chance to rewrite it in Rust?! How dare you, good sir!

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#29

Post by st_goliath »

voidUpdate wrote: post #19
netsharc wrote: post #15

Clicking around the code, it mentions a page with images... even more clicking around got me to this page/image: https://www.ibiblio.org/apollo/Block1.html#DSKY / https://www.ibiblio.org/apollo/Block1ControlPanelDSKY.jpg Damn, a control panel to input values, probably straight to the CPU. I guess the astronauts didn't have to learn assembly, but imagine a programmer having to recite all the raw code (I guess the comm…

The DSKY was the main input system for the AGC, and commands were inputted using the verb/noun system. Verb says what you want to do, and Noun says what you want to do that verb to. For example, "Verb 35 Enter" lights every single segment and light on the DSKY, to make sure they're all working. "Verb 16 Noun 17 Enter" displays the IMU measurements, "Verb 16 Noun 36 Enter" displays the current time and "Verb 16 Noun 4…

While I know about the DSKY, I keep wondering if they were the first ones, i.e. inventing that way of entering data into a computer and others copied it later on, or if it was a already a more widespread and known pattern and the AGC copied it.

I know that other machines existed that used a similar system. I recall being asked, circa summer 2009 or so, to set up extensions on a quite old PABX that was configured that way.

The PABX was a huge electrical box full of giant PCBs stuck into a backplane (S-100 or maybe something proprietary?). I didn't get a good look tough, the box was mounted under the ceiling, directly above a desk with a terminal that you used for configuring it. There was a binder with laminated, typewritten cards, documenting "verbs" and "nouns" that you entered into a numeric keypad. As said, it worked like the Apollo DSKY, but the "display" was single slot that you had to squint through at just the right angle to make out faint numbers on a mirror, aimed downwards at some back projection thingy.

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#30

Post by wim »

This is such an interesting peek into the engineering of these sort of systems with very constrained resources at the time. Like any random file you open contains little pragmatic design decisions like this

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

# THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15 # DAY INTERVAL BEGINNING SHORTLY BEFORE LAUNCH. THEREFORE THE TIME # INPUT BY THE USER SHOULD FALL WITHIN THIS 15 DAY INTERVAL.

Better be back home in 15 days! ;)

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