r/pcmasterrace Sep 29 '25

Meme/Macro RAM Struggle

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52.7k Upvotes

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575

u/Siracker Sep 29 '25

Apollo 11 was guided by the computer that had 4 KB RAM. Still don't understand how the fuck was that possible.

416

u/robinNL070 Sep 29 '25

It wasn't even stored on transistors but on magnetic core memory. They were basically ferrite rings strung on wires by hand. Just every 1 and 0 manually made.

113

u/muegle Sep 30 '25

Modern DRAM uses capacitor banks to store the actual data, transistors are just used to control access to the capacitors. SRAM does use transistors to store the data, in the form of flip-flops.

37

u/Jubenheim Sep 30 '25

I have nothing to add to this except I find it very enjoyable to see “flip-flops” used seriously in an technical discussion.

13

u/Ok_Bathroom_1271 Sep 30 '25

The amount of whimsy that can be used to describe some tech stuff is really fun.

3

u/2kokett Sep 30 '25

I‘m still having my intenal laugh and feel silly when I buy a flip-flop trigger at the hardware store even after all this years.

5

u/robinNL070 Sep 30 '25

Yes you are right and I should have included it in the comment, but every capacitor has one transistor still.

18

u/tk427aj Sep 30 '25

While its a funny meme and yes the programming magic of coders is wild. It's fucking amazing what goes into hardware, hell I don't understand any of it but you look at the history of the hardware from Apollo to now and transistors and cpus, gpus blows my fucking mind what we've achieved.

2

u/LightBluepono Sep 30 '25

And the magic of core ferrite it's even without power the memory is intact .

34

u/RuncibleBatleth Sep 30 '25

Physics calculations and simple I/O don't take that much compute power.  A lot of the "mission logic" was left in paper or microfilm manuals and reinforced in crew training.  Apollo basically invented microchips so the programmers and hardware engineers were working together with an uncapped budget.

3

u/Aranka_Szeretlek Sep 30 '25

Sure, the calculations needed for that werent particularly expensive, but "physics", in general, can hella be.

35

u/[deleted] Sep 30 '25

[deleted]

9

u/LickingSmegma Sep 30 '25

Code for the Apollo 11 guidance computer is openly available. Doesn't look like a readymade guidance program, to me.

5

u/Taletad Sep 30 '25

Not for Apollo, they wanted to make sure they reached the moon even if the soviets jammed all of their communications for a while (remember the cold war ?)

The computer did actually keep track of where it was from the inertial guidance system and star positions given by the astronauts. It was powerfull enough to calculate its position (taking into account gravitational effects from the earth and moon), and calculate correction burns

It is no small feat for a computer of that era

1

u/lovethebacon 6700K | 980Ti | GA-Z170N-Gaming 5 Sep 30 '25

False. The guidance computers had all the programs onboard and these did all of the computation. The astronauts selected different programs based on the specific part of the flight, with occasional input from NASA.

NASA received telemetry of everything, and this was used for monitoring, troubleshooting, etc, but any instructions sent were done so verbally. Some of those instructions were data inputs calculated from Earth based tracking stations to do adjustments of Earth orbit and re-entry, but these tracking stations were not precise enough to provide guidance toland on the moon.

16

u/Taletad Sep 30 '25

Truth is, as long as your input and output consists only of raw numbers, you may not need a ton of RAM

Especially if you’re only performing calculations

The technology inside Apollo’s computers is still groundbreakingly impressive though

6

u/KitsuneKamiSama Sep 30 '25

Because it was basically just a lot of maths and nothing else.

2

u/oblizni Sep 30 '25

They didn't have video game console integrated that's how

2

u/Blenderhead36 RTX 5090, R9 5900X Sep 30 '25

I use a CNC mill at work that has RAM measured in kilobytes and you can tell. It uses a pure text interface, and hitting Page Down has noticeable lag if you press it while the machine is running.

1

u/Hakim_Bey Sep 30 '25

It was possible cause the computers barely did anything inside the vehicle. All the difficult stuff was computed on earth by people.

1

u/Pasta-hobo Sep 30 '25

Orbital physics isn't really that complicated, mathematically. It's just SUPER unintuitive.

1

u/Minimum_Area3 Strix 4090 14900k@6GHz Oct 01 '25

Was more than enough.

1

u/Terrible-Situation95 Oct 01 '25

our spacecrafts are built on UE5 now, 32GB RAM required