Code for Apollo 11 AGC - Page 1
Forum section: electronics / general

author: madires
author_rank: Super Contributor
timestamp: July 11, 2016, 11:54:56 am
content: In case you got an Apollo 11 AGC and need the source code, please checkhttps://github.com/chrislgarry/Apollo-11

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 12:04:57 pm
content: Here's mine. I MUST upgrade the firmware. I might use it to go to Mars, later this week.EDIT:For clarity. I was joking. The picture is a REPLICA one, which I DON'T currently have. (It is an INTERNET picture).

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 01:20:16 pm
content: This has more information about it, including descriptions/details of the instruction set used in it. Which you need to better understanding the listings.https://en.wikipedia.org/wiki/Apollo_Guidance_Computer

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: July 11, 2016, 03:38:10 pm
content: Quote from: MK14 on July 11, 2016, 12:04:57 pmIs that an original DSKY or a replica?

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 03:52:42 pm
content: Quote from: Sal Ammoniac on July 11, 2016, 03:38:10 pmIt is a REPLICA. But I liked the picture so much, I put it in.It is NOT mine (which I hoped was obvious), as I'm NOT really going to Mars this week (the week after, maybe ?).But on seeing it, I now WANT ONE !.EDIT:Sorry if I caused any confusion. I should have been clearer that I was joking. At the time of posting (maybe a bit before, I'm NOT sure), I DID NOT KNOW it was a replica. But found out later. I was amazed their display technology was so good for 1969. But of course it is a replica.I tried to find REAL pictures, but the REPLICA looks much NICER, so I left it in, SORRY!The REAL one (I believe) . . .

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: July 11, 2016, 04:00:51 pm
content: Anyone know where one can buy a replica DSKY? I'd love to have one as a novelty display in my office.

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 04:07:19 pm
content: Quote from: Sal Ammoniac on July 11, 2016, 04:00:51 pmEDIT:Actually it seems to be a PAPER MODEL!!!!!!I'm NOT sure if you can get "electronic" light up ones ?Or maybe you have to make them yourself ?***********************************************************They seem to be on ebay for around $49.99There may be other/better sellers and sources (e.g. Amazon). This is just ONE example I quickly found...http://www.ebay.co.uk/itm/DSKY-DISPLAY-KEYBOARD-APOLLO-GUIDANCE-COMPUTER-AGC-MODEL-CRAFT-KIT-of-LM-5s-/230953345011?hash=item35c5e45ff3:g:P9AAAMXQlUNRUWeY

author: Len
author_rank: Frequent Contributor
timestamp: July 11, 2016, 04:10:51 pm
content: Quote from: madires on July 11, 2016, 11:54:56 amBe sure to check out the bug list first.https://github.com/chrislgarry/Apollo-11/issues/3

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 04:10:58 pm
content: The one I just showed, seems to be a FIXED, non-working replica.Maybe there are proper light up, "working" ones you can get ?

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 04:18:32 pm
content: Quote from: Sal Ammoniac on July 11, 2016, 04:00:51 pmI'm NOT sure if you can buy "Functional"/Light-up ones ?Here are some details on how to make them.http://hackaday.com/2015/02/03/reproducing-a-dsky/

author: SimonR
author_rank: Regular Contributor
timestamp: July 11, 2016, 07:35:27 pm
content: Quote from: madires on July 11, 2016, 11:54:56 amA very interesing find, Now all I need to do is nip down to Tandy and order an AGC to run it on.I considerd getting one of the paper DSKYs but the shipping to the UK was more that the cost of the item at the time.

author: MK14
author_rank: Super Contributor
timestamp: July 11, 2016, 07:40:38 pm
content: Quote from: SimonR on July 11, 2016, 07:35:27 pmYou probably CAN buy them in Tandy's.Since as you enter the Tandy shop (in the UK), you must already be dreaming (or something, as I think they closed a very long time ago), so it may well sell them. (In the fantasy world).I bet if someone made a REPLICA available, with the working/flashing Led displays and lights, they would sell like hot cakes.

author: SimonR
author_rank: Regular Contributor
timestamp: July 11, 2016, 08:05:03 pm
content: I'd buy one. I always fancied a DSKY as an office clock

author: amyk
author_rank: Super Contributor
timestamp: July 13, 2016, 11:37:16 am
content: ...and if you feel like building the actual CPU hardware, there's schematics here:http://klabs.org/history/ech/agc_schematics/

author: MK14
author_rank: Super Contributor
timestamp: July 13, 2016, 11:55:56 am
content: Quote from: amyk on July 13, 2016, 11:37:16 amThanks for that link, it looks VERY interesting. The schematics are nice and very clean, they have been well preserved. (Presumably stored on microfilm, maybe).A quick glance, seems to show it is built exclusively out of Nor gates, which themselves are made out of three transistors, in a resistor transistor logic configuration (i.e. probably RTL). I think they are then made out of early, simple integrated circuits.It is a bit like the Cray1 supercomputer, which was also made out of simple, single function logic gates (mostly), ECL.The memory (probably core for the Apollo 11), and other stuff are done differently.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: July 13, 2016, 04:01:02 pm
content: Quote from: MK14 on July 13, 2016, 11:55:56 amYep, the entire computer is built from thousands of three input NOR gates. The chips themselves were built by Fairchild and each one had two gates. Yes, they were RTL logic. The Apollo AGC was one of the first to use integrated circuits rather than discrete transistors. The word length was 16 bits, with one bit acting as an overflow bit and one as a sign bit. Numbers were represented in ones complement.The AGC did use core. Core rope for the read-only program store and planar core for the writable memory.

author: nfmax
author_rank: Super Contributor
timestamp: July 13, 2016, 04:11:20 pm
content: Not only did the AGC use these ICs, the ground test equipment used the same parts. Approximately 80% of US IC production at the time went to the Apollo programme. They wanted to ensure the parts would stay in production long enough to get to the moon & back

author: MK14
author_rank: Super Contributor
timestamp: July 13, 2016, 05:50:23 pm
content: Quote from: Sal Ammoniac on July 13, 2016, 04:01:02 pmQuote from: nfmax on July 13, 2016, 04:11:20 pmReplying to both of you at the same time.(from a quick glance at it), I think they did a really good job, of designing that computer (I'm especially surprised at the drawing quality of the schematics. I'm use to hand drawn stuff in that era. Maybe they used stencils/protractors/shapes etc to do it, or some kind of crazily early CAD/EDA software). Except maybe they should have considered 8 bits, which could have drastically reduced the hardware size, in theory. But maybe 16 bits was the right choice.Also from a quick look at the instruction set (the other day), it seems to be a very early RISC like architecture, although maybe that is a matter of opinion. Certainly it seems to have very few instructions, but they seem to have crammed all the sort of functionality that one would need, into them.Taking the time when they did this into consideration (pre-1969, obviously), they did quite an amazing job. Even the first microprocessors had not been invented (as regards available on the open market), yet. Although some people (me included) argue that some of the pre-microprocessor cpu chips, were actually almost processors in their own right.E.g. TTL 74181 4 bit ALU. It is almost a TTL based, 4 bit arithmetic Logic "microprocessor", in its own right. Technically it is not a processor and is missing many of the units in a single chip microprocessor. But on the other hand, it is a sort of 4 bit-sliced (partial) processor.Ignoring the political/philosophical ramifications. This Apollo AGC, was probably an early version of the TTL based, computers, used for the Nuclear weapon deterrent systems, of that era. Some sources say that the ballistic missile program, effectively paved/paid the way for the development of TTL, and hence the start of the computer revolution.Early (especially hand built) Germanium transistors, were rumored to be terribly unreliable (by today's standards). So these three (or 6) transistor IC's, should be especially reliable, surviving the huge G forces, and safety/reliability requirements of space.But I can believe by then, reliable transistor production and/or Silicon transistors, could be mass produced, and were fairly reliable.Although 1960's electronics had a tendency to be unreliable, anyway. Reliable construction techniques were in their infancy, especially for space environments.I'm a bit surprised that core memory (with potentially weak/flimsy wires and fragile magnetizable cores and stuff) can take the huge G forces, and harsh environment, strict reliability and safety requirements for a space mission. Also the fact that you have to "write" to it, in order to "read" from it, would worry me, as well. As it makes it sound intrinsically unreliable/delicate.I guess the "ROM" version, may have used a technique so that it is not writable. I.e. non-destructive reads. I.e. permanent magnets as cores, if that even works technically and/or is practicable to put in the individual 0's and 1 bits in by hand. I vaguely remember reading somewhere or a Youtube program, mentioning something like that. Where women would patiently assemble the cores and it would take months to make each one.I can imagine in 10 years time, putting on a VR helmet, and then getting into a life like virtual simulation of the Apollo 11 space craft, then flying and landing on the Moon.

author: SimonR
author_rank: Regular Contributor
timestamp: July 13, 2016, 07:53:10 pm
content: As mentioned elsewhere on this forum a really good read if your interested in this is"The Apollo guidance computer, architecture and operation" from Frank O'Brian at Springer.It tells you exactly how the memory was used, although not how it worked.I suspect that magnetic core was the most reliable and robust memory available at the time, 1960/61 when the project started. Think about it, the alternative was mercury delay line or nickel delay line memory. Mercury weighed more than a Saturn 5 and external vibration in nickel wires would have destroyed the data.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: July 13, 2016, 08:26:50 pm
content: Quote from: MK14 on July 13, 2016, 05:50:23 pmI'm not. Remember that this was a government-funded project with a nearly unlimited budget. No expense was spared in anything, including the documentation. The size of the team developing the computer and writing the software was around 600 at its max size.What does surprise me is that these schematics survived until now. A lot of the Apollo documentation was destroyed due to lack of space in government warehouses.QuoteThe memory, along with most of the rest of the computer, was potted in epoxy resin. There were no "huge" G forces involved -- remember that this computer was used on amannedspacecraft, and men can't withstand huge G forces. Max G was probably in the 7-9 G range.

author: SimonR
author_rank: Regular Contributor
timestamp: July 13, 2016, 08:33:28 pm
content: I'd forgotten that they potted everything, that would make it even more resilient.The same memory wqs used in the shuttle for half its life, I believe, right up until they refitted it with al glass instruments.

author: rrinker
author_rank: Super Contributor
timestamp: July 13, 2016, 08:57:41 pm
content: Quote from: MK14 on July 13, 2016, 05:50:23 pmI for one, would hope it comes sooner than 10 years, just to be sure I'm still around - but I would most definitely buy something like that. Recordings of the Apollo 11 touchdown trigger memories I can't otherwise readily recall - I was 3 years old when that happened, but I most definitely was watching and there's like a deja vu moment when I hear the radio chatter.

author: smgvbest
author_rank: Unknown
timestamp: July 17, 2016, 05:34:17 am
content: This is something on my TODO list. I really want to recreate the DSKY Been collecting information for some time on ithere's two nice oneshttp://www.ibiblio.org/apollo/Pultorak.htmlHere'sa FPGA implementation of the AGChttps://github.com/donnaware/AGCMy Favoritehttp://nassp.sourceforge.net/wiki/Main_Pageget the orbiter simulator from herehttp://orbitersimulator.com/You can also find various youtube video'ssearch for DSKY AGC

author: MK14
author_rank: Super Contributor
timestamp: July 17, 2016, 09:30:06 am
content: Quote from: rrinker on July 13, 2016, 08:57:41 pmVR should be coming somewhat soon (ignoring very early stuff), maybe later this year (if it's on time), or next year. But that will probably be mainly for early VR gaming and stuff.How long it takes before we have the first Apollo 11 AGC (and similar) stuff, I'm much less certain about.Before I stray too off-topic. I'll just say that I'm not sure how VR is going to progress, because some people would prefer to just sit down and watch movies/TV and/or games. Yet some VR thingies, involve standing up and moving about in "safe"/empty (relatively) rooms. Which I imagine would get too exhausting, after an hour or two, depending on ones fitness.I would imagine that the Apollo 11 AGC is a fairly obvious target for future VR systems. So it makes sense that the VR people, will go for it at some point.At this point in time, it is not obvious, how successful VR will be, either.

author: newbrain
author_rank: Super Contributor
timestamp: July 17, 2016, 04:00:33 pm
content: Not strictly related to the AGC, but I think still in topic:The well known (at least in Italy) blogger and debunker Paolo Attivissimo has collected a vast amount of audio and video documentation, and created an extremely interesting and high quality documentary video on the Apollo 11 landing:QuoteYou can find it here:https://moonscapemovie.blogspot.it/Apart for appreciating his effort and dedication, and a small contribution, I'm not affiliated with the project.

author: SimonR
author_rank: Regular Contributor
timestamp: July 23, 2016, 06:21:26 pm
content: Not strictly AGC related but here is a complete 3D scan of the inside of the Apollo 11 CMhttp://3d.si.edu/apollo11cm/boxes/play-cm-ext-rc6-int-rc5/cm-interior.html

author: MK14
author_rank: Super Contributor
timestamp: July 23, 2016, 10:54:32 pm
content: Quote from: SimonR on July 23, 2016, 06:21:26 pmThanks, that is fun, interesting and educational to play with.I did not realize that the flight computer, had buttons, labeled, 'Noun' and 'Verb'. They are to initiate and something, 2 digit commands. I guess since it was a very early computer, even knowing how to label up the keyboard was new to everyone. Since embedded computers were fairly rare, then, I would think.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: July 24, 2016, 12:39:18 am
content: I liked the hand-written message by Michael Collins in the lower equipment bay.