Mike makes an Apollo core rope reader (Patreon)

This is the USB peripheral you were all waiting for: the Apollo core rope reader, another creation of our AGC restoration hero Mike Stewart.

Not only he made it work, but he made it look cool, with a lightweight metal case mimicking the case design of the AGC.

Just plug it in your computer, slide in your core rope, and you are ready to go explore Apollo mission code.

He had not yet tested it with a real core rope, so the first try yielded some red lights, with most of the rope not read correctly. However the first block of addresses read nice and green, so that was quite an impressive start, if you ask me.

That's when he fired his (freely available) Apollo core rope simulator, and quickly figured out an addressing problem. Core rope addressing is very complicated compared to regular core memory. So much so, that he made this simulator to figure it out. In rope, you don't use coincident current like in regular core memory. You inhibit all cores except one. In the picture below, the darker the red, the more inhibited the particular core is. If you do it correctly, only one core will be un-inhibited. And that single core enables you to read 192 bits of information. It's going to take a lot of elevator music to explain all that.

So he figured out the problem, recompiled his FPGA code, and a few minutes later, he successfully recovered the entirety of the core rope module. All the lights were green! This trial module was from already known code, so he could double check from the original listing (in the background), and the checksum, that he got it right.

Since then, Mike has already recovered several Block II core ropes for which there were no listings remaining. 

And he did not stop there! He made a second hardware version for Block I core ropes, which he gave a preview of on our improvised livestream. Block I ropes modules are quite different, not only in their form factor, but also in their addressing and required currents, compared to Block II. 

He is flying out tomorrow to collectors that have some elusive Block I ropes, so he can start to read them.

Marc (and Mike)