Apollo Core Rope Memory (Apollo Guidance Computer Part 30)

Core Rope Memory, which contained the programs that landed man on the Moon in the 1960s, is insanely complicated. But that won't stop Mike from making a custom reader for it, so he can recover Apollo Guidance Computer programs lost to history.

Core Memory Videos:

Stuff that supports the channel:
- Amazon links for the tools I use in the lab (supports the channel if you buy from there)

Our lovely sponsors

00:00 Intro: Apollo Guidance Computer restoration
02:21 What is core rope memory?
05:16 Previous core rope recoveries with our AGC
06:44 Our AGC is sold at auction
07:36 Mike's core rope reader prototype
11:09 Last minute core rope "hack" for Apollo 11
14:04 Software recovered so far
14:48 Trying the reader for the first time and error
17:56 Core rope explanation: data encoding
20:13 Transformer rope is not core rope
21:24 Core rope explanation: reading using bistable cores
26:09 Core rope explanation: molybdenum permalloy cores
28:22 Experimental demo of moly cores
31:49 Core rope explanation: addressing with inhibits
33:59 Apollo core rope simulator, inhibit wires
35:56 Set and reset wires
37:45 Parity wires and the design error
45:02 Mike fixes the reader and tries again
47:38 Success! Congrats Mike!

[ZaphodHarkonnen]

Huge props to the auction house and the previous owner for letting you read the memory modules. Sure it was only a minor risk but they didn’t have to say yes. ❤

[agluebottle]

The seamstresses who wove the rope core memory by hand were incredible. Total unsung heroes of the Apollo Program.

[readams]

I'm hoping Lenovo adds a core rope slot to the next Thinkpad

[RichardFraser-yt]

You just never know when you need a rope core memory reader.

[fridgeffs]

Im one of the original creators of the memory modules. We were so happy to find out about your work. Thank you for keeping this great part of history alive!

[RicoD]

It’s already 4 years since you started the Apollo series. They spread such valuable knowledge and preserve the great Apollo history. Thanks to you all for making my day just a little better. Again and again.

[petesapwell]

I’m a tech, I repair old arcade machine game boards & thought I was quite smart, Mike makes me feel like a complete idiot :) and that makes me happy, brilliant work you guys. I’m going to have to re listen/watch the explanation of how this crazy stuff works! Happy Days

[rainerkaskinen]

I cant imagine how smart Mike and Marc are, it’s beyond belief! Guru level 1337!!!

[I]

This video makes all the vintage HP equipment repair videos look nice and easy.
Thanks for the exhaustive explanation of all the magnetic magic, Marc.

[elioboezio]

Whenever I start getting ideas that I might actually be comparatively intelligent, I watch this channel and it brings me back down to Earth with a bump - and my knuckles go back to dragging on the ground! These guys are seriously smart: rocket scientists, even!

[henrivanbemmel]

Mike is just amazing. Honestly, for his work recovering this important American history, I think he should be nominated for a Congressional Space Medal of Honour. What he has done with exceptionally limited resources is just remarkable!!! Damned well done!

[mahtin]

“We will explain what they do in painful detail later” - love it! This is why we tune in for every video! Thank you Mark, Mike, Ken, etc.

[Richard]

When I first joined IBM I was offered a job operating a tool to "weld" the ends of the wires fed through the memory array frames. I declined the job and took a job in the warehouse instead. Ferrite core memory arrays were assembled in the UK and sent to Portugal to have a single gold wire fed through the centre of the array, They were then shipped back to us in the UK to assemble in the mainframes in production. This was 1969.

[philkarn]

The key to understanding "core" rope memory is that the cores don't store anything themselves. They're actually a clever memory address decoding mechanism. I worked out that if the dual 3-input NOR gate chips used elsewhere in the AGC had been used in address decoders, it would have required many more than in the actual computer.

[berndheiden]

After having my synapses rewired watching you guys decipher the lost programs my subconscious asked me a bewildering question. „Wasn‘t flying to the moon the biggest technical achievement of mankind so far?“ Not knowing where that went I nodded. And then the next question hit home. „Wouldn’t you think, that everything leading to that goal was shrined to let our children know how we put the first human on another piece of rock in our solar system?“ Now I got suspicious but still nodded. the next question will keep me wondering for a while. „What else have we recklessly discarded and how much has simply vanished, never to be fully understood and appreciated?“

You all are doing a very important job that should be liberally funded by universities, museums and government. Thanks for your good work!

[slothjr]

The more I see what Mike gets up to, the more impressed I am.

[dadbear]

I wish I had the level of ingenuity that the engineers who made Apollo possible had, I am but a humble engineer standing on the shoulders of giants

[Ratje]

In genuine awe of the knowledge, passion and skill of Mike just now.

[VladAndreis]

I know it's been said before but the way those core rope memory modules were made is a true work of art. The Apollo program was cutting-edge engineering and art intertwining in a beautiful symbiotic way. I get goosebumps every time I see a non-potted module.

[carpetbomberz]

Mike (and everyone else in this band of merry pranksters) is unstoppable, relentless even. And we are all the better for it. 👍