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How would I make my own bubble memory? (lemmy.sdf.org)

submitted 1 year ago* (last edited 1 year ago) by CanadaPlus@lemmy.sdf.org to c/retrocomputing@lemmy.sdf.org

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It's a good candidate since it sounds like there's no precision mechanical components like there would be in a hard drive. Does anyone have ideas for how I'd go about this? Is there a barrier I'm not considering?

I know how to make basic semiconductors already, so that's not an issue.

Edit: I've got an answer written down in the comments now. TL;DR you'd still need lithography to do it the OG way, because of the patterned magnetic material that directed bubbles around the medium, but material requirements are actually pretty flexible.

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[–] MossyFeathers@pawb.social 1 points 1 year ago (2 children)

I know how to make basic semiconductors already, so that's not an issue.

Uh, do you mean you know how to design them and send them somewhere to be made, or do you actually make them yourself? I thought you needed a crazy manufacturing plant for that.

As for making bubble memory, have you considered the material requirements? It looks like bubble memory used gadolinium gallium garnet, or yttrium iron garnet. Additionally, it sounds like bubble memory is significantly more complex than you'd think because while there aren't any mechanical components, it sounds like there are moving components.

[–] jaredj@infosec.pub 6 points 1 year ago (1 children)

Sam Zeloof has made chips in his garage and posted a whole series about it on Youtube. He bought his silicon wafers, he didn't grow them, and his machines do take up the whole garage - but he did the whole thing himself. Fascinating viewing IMO. I don't know anything about where one would get these garnetty materials you mention, though.

[–] CanadaPlus@lemmy.sdf.org 3 points 1 year ago* (last edited 1 year ago)

So, I'm still doing research, but it seems like any ferrimagnetic thin film should work.

Rare earths would have been in lower demand at the time I think, some garnets have useful magnetic properties, and growing garnets is relatively easy. Similar synthetic crystals are common as lasing mediums now.

[–] CanadaPlus@lemmy.sdf.org 5 points 1 year ago

Uh, do you mean you know how to design them and send them somewhere to be made, or do you actually make them yourself? I thought you needed a crazy manufacturing plant for that.

Here's a link to my favourite YouTuber, Sam Zeloof, on Invidious! If you want to see him actually do it, the "Transistor Step By Step" video is good.

As for making bubble memory, have you considered the material requirements? It looks like bubble memory used gadolinium gallium garnet, or yttrium iron garnet.

That's one of the big questions. Do I need exotic materials, or were they just better from the perspective of a 1970's manufacturer? If I can make a bad one with some kind of ferrite that's still something.

Additionally, it sounds like bubble memory is significantly more complex than you’d think because while there aren’t any mechanical components, it sounds like there are moving components.

If it's a matter of electrical control, though, that becomes an analytical problem which I'm pretty good at. I also have the advantage of access to 2020s electronics, so if I need to measure or control things on the order of microseconds it's no big deal.