Don Eyles Walks Us Through the Lunar Module Source Code • Hacker News Board

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#11

Post by outworlder » Tue, Jul 05, 2016, 4:38 PM UTC

lisper wrote: post #9

Arnavion wrote: post #5

Earlier quoted context omitted.

>with no hope of doing an update To be fair, space probes occasionally do get software updates, eg http://blogs.esa.int/rosetta/2014/03/28/software-upgrade-at-... In the case of the Curiosity Rover, it didn't even "ship" with the software of what it was supposed to do on Mars until it had landed there http://www.space.com/17034-mars-rover-curiosity-software-upg... Edit: I'm not saying this was possible in 1969. I pos…

> space probes occasionally do get software updates Sure. In 2014. Not in 1969. I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft. It used an 1802 processor with 2k bytes of memory and was programmed in Forth. The development system ran on an Apple II. The instrument developed a bad byte of RAM and so a…

> I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft.

Sigh. Reading this at the start of my workday is not doing wonders to my morale.

Only tangentially related to the article, but since you are commenting here, I'd like to thank you for the "Lisping at JPL". I've read it several times, which caused me to start collecting all the info I could get on the Remote Agent. I couldn't find that much though. Surely such a project should have generated way more research papers than it did? Since it doesn't seem to be used anymore, where's the source code? It feels like it was killed with fire.

I wonder if current generation spacecraft now have something even half as powerful as the DS1 REPL...

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#12

Post by jritchie » Tue, Jul 05, 2016, 4:44 PM UTC

lisper wrote: post #9

Arnavion wrote: post #5

Earlier quoted context omitted.

>with no hope of doing an update To be fair, space probes occasionally do get software updates, eg http://blogs.esa.int/rosetta/2014/03/28/software-upgrade-at-... In the case of the Curiosity Rover, it didn't even "ship" with the software of what it was supposed to do on Mars until it had landed there http://www.space.com/17034-mars-rover-curiosity-software-upg... Edit: I'm not saying this was possible in 1969. I pos…

> space probes occasionally do get software updates Sure. In 2014. Not in 1969. I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft. It used an 1802 processor with 2k bytes of memory and was programmed in Forth. The development system ran on an Apple II. The instrument developed a bad byte of RAM and so a…

> Sure. In 2014. Not in 1969.

The LM computer on Apollo 14 had to be updated in flight in order to bypass a faulty abort switch.[1] The patch was applied by radioing the instructions to the crew and having them enter it manually.

[1] https://www.hq.nasa.gov/alsj/a11/a11.1201-pa.html

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#13

Post by lisper » Tue, Jul 05, 2016, 4:59 PM UTC

outworlder wrote: post #11

lisper wrote: post #9

Earlier quoted context omitted.

> space probes occasionally do get software updates Sure. In 2014. Not in 1969. I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft. It used an 1802 processor with 2k bytes of memory and was programmed in Forth. The development system ran on an Apple II. The instrument developed a bad byte of RAM and so a…

> I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft. Sigh . Reading this at the start of my workday is not doing wonders to my morale. Only tangentially related to the article, but since you are commenting here, I'd like to thank you for the "Lisping at JPL". I've read it several times, which caused me…

> Reading this at the start of my workday is not doing wonders to my morale

I'm very sorry to hear that. Would it help if I told you how my life sucks now? ;-)

> Surely such a project should have generated way more research papers than it did? Since it doesn't seem to be used anymore, where's the source code?

I have no idea. I strongly suspect that the RAX code was not preserved, though I could be wrong. You might want to contact the JPL public-relations office and ask them.

It is hard to appreciate just how chaotic the entire DS1 project was. The mission was trying to do things that had never been done before on a budget and schedule that was a tiny fraction of anything that had come before. And then RAX was a little cauldron of chaos within the larger chaos. We were a team forced to work together by largely political rather than technological considerations. We were using CVS for version control (this was the mid-90's remember). It was all we could do to come up with something that worked at all. It was very stressful, and when it was over, everyone just wanted to distance themselves from it as fast as possible. There was no money for anyone to properly catalog and archive the code (AFAIK).

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#14

Post by mmastrac » Tue, Jul 05, 2016, 5:03 PM UTC

xhrpost wrote: post #8

There's a link to the source code on GitHub[0], is that not the full source though? Just searching for a comment like 'hello there' from the photo[1] doesn't seem to exist in the repo. [0] https://github.com/chrislgarry/Apollo-11 [1] https://hackadaycom.files.wordpress.com/2016/07/apollo-sourc...

Googling some of the surrounding lines suggests that it is available here:

https://github.com/avtobiff/virtualagc/blob/master/Luminary1...

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#15

Post by heywire » Tue, Jul 05, 2016, 5:09 PM UTC

lisper wrote: post #9

Arnavion wrote: post #5

Earlier quoted context omitted.

>with no hope of doing an update To be fair, space probes occasionally do get software updates, eg http://blogs.esa.int/rosetta/2014/03/28/software-upgrade-at-... In the case of the Curiosity Rover, it didn't even "ship" with the software of what it was supposed to do on Mars until it had landed there http://www.space.com/17034-mars-rover-curiosity-software-upg... Edit: I'm not saying this was possible in 1969. I pos…

> space probes occasionally do get software updates Sure. In 2014. Not in 1969. I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft. It used an 1802 processor with 2k bytes of memory and was programmed in Forth. The development system ran on an Apple II. The instrument developed a bad byte of RAM and so a…

> I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft.

One of the many reasons why I love reading the comments on this site.

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#16

Post by jgrahamc » Tue, Jul 05, 2016, 5:12 PM UTC

gumby wrote: post #3

szczys wrote: post #2

There's something amazing about carrying around your dot-matrix printed source code in a roller suitcase. The only thing that says "stable release" more than printing it out on hundreds of pages of paper is launching the computer running the code into space with no hope of doing an update.

Thats line printer output. Dot Matrix was only invented in the late 60s and in any case was too slow, being character at a time.

And you don't know terrifying power until you've seen a line printer going at full speed.

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#17

Post by diego898 » Tue, Jul 05, 2016, 5:18 PM UTC

If you enjoy this, you might also enjoy a DIY Apollo Guidance Computer build by John Pultorak [1]:

"John Pultorak created a working reproduction of the Apollo Guidance Computer (AGC), wrote a complete manual that will allow you to build your own Apollo flight computer clone and released it in the public domain."

[1]: http://www.galaxiki.org/web/main/_blog/all/build-your-own-na...

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#18

Post by outworlder » Tue, Jul 05, 2016, 5:31 PM UTC

lisper wrote: post #13

outworlder wrote: post #11

Earlier quoted context omitted.

> I once had the very interesting experience of developing an in-place update for a mid-1980s-vintage spacecraft instrument: the magnetometer on the Galileo spacecraft. Sigh . Reading this at the start of my workday is not doing wonders to my morale. Only tangentially related to the article, but since you are commenting here, I'd like to thank you for the "Lisping at JPL". I've read it several times, which caused me…

> Reading this at the start of my workday is not doing wonders to my morale I'm very sorry to hear that. Would it help if I told you how my life sucks now? ;-) > Surely such a project should have generated way more research papers than it did? Since it doesn't seem to be used anymore, where's the source code? I have no idea. I strongly suspect that the RAX code was not preserved, though I could be wrong. You might wa…

> I'm very sorry to hear that. Would it help if I told you how my life sucks now? ;-)

Not at all. It would only increase the (perceived!) overall suckyness of the universe :)

> I have no idea. I strongly suspect that the RAX code was not preserved, though I could be wrong. You might want to contact the JPL public-relations office and ask them.

I didn't know that such an attempt could have a greater than zero chance of success. Let's see how that goes.

> And then RAX was a little cauldron of chaos within the larger chaos.

And yet, it flew!

> It was very stressful, and when it was over, everyone just wanted to distance themselves from it as fast as possible.

Uh oh. That's far worse than having no budget for archival.

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#19

Post by lisper » Tue, Jul 05, 2016, 5:40 PM UTC

outworlder wrote: post #18

lisper wrote: post #13

Earlier quoted context omitted.

> Reading this at the start of my workday is not doing wonders to my morale I'm very sorry to hear that. Would it help if I told you how my life sucks now? ;-) > Surely such a project should have generated way more research papers than it did? Since it doesn't seem to be used anymore, where's the source code? I have no idea. I strongly suspect that the RAX code was not preserved, though I could be wrong. You might wa…

> I'm very sorry to hear that. Would it help if I told you how my life sucks now? ;-) Not at all. It would only increase the (perceived!) overall suckyness of the universe :) > I have no idea. I strongly suspect that the RAX code was not preserved, though I could be wrong. You might want to contact the JPL public-relations office and ask them. I didn't know that such an attempt could have a greater than zero chance o…

> And yet, it flew!

Yes, it did. And it even mostly worked. And even when it didn't work it let us demonstrate in-situ debugging and repair, which had also never been done before (and AFAIK has not been done since).

> That's far worse than having no budget for archival.

Indeed. :-(

Re: Don Eyles Walks Us Through the Lunar Module Source Code

#20

Post by nervousvarun » Tue, Jul 05, 2016, 6:33 PM UTC

sizzzzlerz wrote: post #4

szczys wrote: post #2

There's something amazing about carrying around your dot-matrix printed source code in a roller suitcase. The only thing that says "stable release" more than printing it out on hundreds of pages of paper is launching the computer running the code into space with no hope of doing an update.

Kids, today! You have no idea how lucky you are. At the time of writing this code, there were no 32" color monitors, IDEs, code text editors, or source code management systems. Code was first written out by hand and then typed onto punch cards or paper tape. These were fed into a mainframe computer for assembly. If you made a mistake, you had to find cards (by hand), remove and replace them with corrected cards. Get…

Yup..."back then" you would arrange all your cards in a shoebox and then take a marker and make a diagonal mark from top left to bottom right JUST IN CASE you dropped said shoebox on the way to class to turn in your homework/take home test. Without that mark there's no easy way to recreate the correct order of the punch cards.

Source: dad was an engineering major in the early 70s.