> Apollo 11 spacecraft contains 4 computers<p>Analog computers don't get the respect they deserve. There's one more computer, the FCC. The Flight Control Computer is an analog computer in the Saturn V that controlled the rocket gimbals. It's a two-foot cylinder weighing almost 100 pounds.
I'm a bit tired of all the sensationalist "look what landed on the moon vs. today's hardware" comparisons. The first airplanes didn't have any sort of computer on board, so computation power is not the single deciding factor on the performance and success of such an endeavor.<p>The software (and hardware) of the Apollo missions was very well-engineered. We all know computation became ridiculously more powerful in the meantime, but that wouldn't make it easy to do the same nowadays. More performance doesn't render the need for good engineering obsolete (even though some seem to heavily lean on that premise).
Is the weight/cost calculus sufficiently improved now that it’s cheaper to shield the processor in it’s entirety rather than trying to rad harden the circuitry itself (much more expensive due to inability to use off the shelf parts & limits the ability to use newer tech)?<p>If I recall correctly this was one of the areas being explored by the mars drone although not sure if Mars surface radiation concerns are different than what you would use in space.
Pretty much all USB chips have a fully programmable CPU when you go into the data sheets. It feels silly for simple hid or charging devices but basic microcontrollers are cheap and actually save costs compared to asics.
>> others point out that the LVDC actually contains triply-redundant logic. The logic gives 3 answers and the voting mechanism picks the winner.<p>This is a very minor point... but three of something isn't triple redundancy: it's double redundancy. Two is single redundancy, one is no redundancy.<p>Unless the voting mechanism can somehow produce a correct answer from differing answers from all three implementations of the logic, I don't understand how it could be considered triply redundant. Is the voting mechanism itself functionally a fourth implementation?
I'm curious - are there any ways of finding out the precise hardware that's used in these small-scale devices that are generally not considered to be computers (like smartphone chargers) without actually having to take them apart? Are there special datasheets, or perhaps some documents for government certification, or anything like it? I've always been fascinated with the barebones, low-spec hardware that runs mundane electronic things, so I want to know where the author got all that information from.
> The Anker PowerPort Atom PD 2 USB-C Wall Charger CPU is 563 times faster than the Apollo 11 Guidance Computer<p>Wild to think the thing that charges my devices could be programmed to put a human on the moon
So in 50 years the equivalent of a gpt4 training cluster from today's datacenters will fit in a cheap cable, and it will run over 100 times faster than a full cluster today.
> the LVDC actually contains triply-redundant logic<p>I didn't know that was just for the LVDC.<p>> emulate this voting scheme with 3x microcontrollers with a 4th to tally votes will not make the system any more reliable<p>I think that's clear enough; the vote-tallier becomes a SPOF. I'm not sure how Tandem and Stratus handled discrepancies between their (twin) processors. Stratus used a pair of OTC 68K processors, which doesn't seem to mean voting; I can't see how you'd resolve a disagreement between just two voters.<p>I can't see how you make a voting-based "reliable" processor from OTC CPU chips; I imagine it would require each CPU to observe the outputs of the other two, and tell itself to stop voting if it loses a ballot. Which sounds to me like custom CPU hardware.<p>Any external hardware for comparing votes, telling a CPU to stop voting, and routing the vote-winning output, amounts to a vote-tallier, which is a SPOF. You could have three vote-talliers, checking up on one-another; but then you'd need a vote-tallier-tallier. It's turtles from then on down.<p>In general, having multiple CPUs voting as a way of improving reliability seems fraught, because it increases complexity, which reduces reliability.<p>Maybe making reliable processors amounts to just making processors that you can rely on.
Too bad the link to Jonny Kim's biography is broken (one that works: <a href="https://www.nasa.gov/people/jonny-kim/" rel="nofollow">https://www.nasa.gov/people/jonny-kim/</a>). He has to be one of the most impressive humans who has ever lived. Amongst other things, a decorated Navy SEAL, Harvard medical doctor, and astronaut. Sounds like a kid slapping together the ultimate G.I. Joe.
Discussed at the time (of the article):<p><i>Apollo 11 Guidance Computer vs. USB-C Chargers</i> - <a href="https://news.ycombinator.com/item?id=22254719">https://news.ycombinator.com/item?id=22254719</a> - Feb 2020 (205 comments)
Remarkable comparison! I'm surprised it had only one parity bit per 15-bit word. Even on Earth today we keep two parity bits per 8-bit word in most of our servers.<p>> IBM estimated in 1996 that one error per month per 256 MiB of RAM was expected for a desktop computer.<p><a href="https://web.archive.org/web/20111202020146/https://www.newscientist.com/blog/technology/2008/03/do-we-need-cosmic-ray-alerts-for.html" rel="nofollow">https://web.archive.org/web/20111202020146/https://www.newsc...</a>
If anyone is interested, there is a 1965 documentary about an Apollo computer:<p><a href="https://youtube.com/watch?v=ndvmFlg1WmE" rel="nofollow">https://youtube.com/watch?v=ndvmFlg1WmE</a>
> The CYPD4225 is definitely not rated for space.. if it would work in space<p>It will. Not too long and not very reliable, but will.<p>From history of space rockets, they was definitely first created as "two purpose" (except, may Vanguard, which was totally civilian program), so their electronics considered possible radiation from nuclear war, but fortunately, in space found natural radiation, but slightly other type (spectrum).
Currently, SpaceX just use industrial grade computers on rockets (not RAD hardened).<p>Well, look at tech details: for RAD digital electronics exists two types of problems.<p>1. Random spikes (switches) from high energy charged particles.
Unfortunately, only Military RAD grade parts have integrated safety mechanisms, for Civ/Industry grades, could make shield with EM field and thick layer of protecting material, like Lead or even Uranium.
When thyristor effect happen, need to power circle (turn off/on and boot), and this is risks source for mission, but most probably, it will withstand flight to Moon.<p>2. Aging of semiconductor structure from constant flow of particles with high penetration - basically it is just high speed diffusion, which destroy semiconductor structures.
But for Earth-Moon environment, this is issue for long term operations (months or even years).<p>So, will work.
When we go back to the moon, I wouldn't be surprised if Zilog-Z80s were a major part of the hardware. Well known, well understood, predictable hardware goes a long way. There's a bunch of other considerations in outer space and z80s have proven robust and reliable there. Also I'd expect a bunch of Kermit and Xmodem to be used as well.
The great thing about the AI age is that we are once again performance constrained so people start to rediscover the lost art of actually optimizing a program or runtime (the last such age were the waning days of ps2. Those guys made GoW 2 run on 32 megs of ram ... respect)
It has certainly felt like the limit is software/PEBKAC for a long while. Until lately with LLMs...that does make me feel "wish I had a bigger hammer" again.
It is amazing they were able to miniaturize a computer to fix into a spaceship.<p>Previously calculators were a room full of people, all of which required food, shelter, clothing and ... oxygen.
Weird question maybe, but does anyone keep track of quantitative or qualitative data that measures the discrepancy between consumer (commercial) and government computer technology?<p>TBH, it's kind of amazing that a custom computer from 50 years ago has the specs of a common IC/SoC today, but those specs scale with time.
The ariicle was a lot of fun however I felt it missed a important aspect about the respective computers. IO channels. I don't know about the USB charge controllers. But the AGC as a flight computer had a bunch of inputs and outputs. Does a Richtek RT7205 have enough IO?
Seems like with cables this powerful, it might make sense for some devices to simply run their logic on the cable CPU, instead of coming with their own.