Retro Memory Hack Chat

A trip down memory lane

Wednesday, November 3, 2021 12:00 pm PDT Local time zone:
Hack Chat
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Andy Geppert will host the Hack Chat on Wednesday, November 3 at noon Pacific.

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With how cheap and easy-to-integrate modern memory chips have become, it's easy to lose track of the fact that it wasn't too long ago that memory was the limiting factor in most computer designs. Before the advent of silicon memory, engineers had to make do with all sorts of weird and wonderful technologies just to provide a few precious bytes of memory. Things like intricate webs of wires spangled with ferrite cores, strange acoustic delay lines, and even magnetic bubbles were all tried at one time or another. They worked, at least well enough to get us to the Moon, but none would prove viable in the face of advancements in silicon memory.

That doesn't mean that retro memory technology doesn't have a place anymore. Some hobbyists, like Andy Geppert, are keeping the retro memory flame alive. His Core64 project puts a core memory module in the palm of your hand, and even lets you "draw" directly to memory with a magnet. Andy learned a few tricks along the way to that accomplishment, and wants us all to appreciate the anachronistic charm of retro memory technologies. Stop by the Hack Chat to talk about your memories of memory, or to just learn what it used to take to store a little bit of data.

  • Hack Chat Transcript, Part 2

    Dan Maloney11/03/2021 at 20:14 0 comments

    Usagi Electric (David)12:39 PM
    Have you tried played around with any other types of vintage computer memory? Drum memory seems to have been the primary memory used until core memory became viable, but Williams Tubes were also super interesting.

    Ken Berkun12:39 PM
    No, the audio was standard amplifier, the core was used to remember which songs you selected.

    anfractuosity12:39 PM
    aha, gotcha

    Ken Berkun12:39 PM
    I really miss have a jukebox and a pinball machine, must do that again!

    Ken Berkun12:40 PM
    The neighborhood kids loved them, and when one turned to crime he burglarized other homes, but not ours.

    anfractuosity12:40 PM
    Silly question, although it says the cores are ferrite which does sound to be rust mixed with another metal, would straight iron not work as a core? or is there something about the ferrite being suspended in another metal, that lets it change magnetisation?

    Kelly Heaton12:40 PM
    Does anyone know any examples of living organisms that use a core memory model?

    Andy Oliver12:41 PM
    @anfractuosity "core memory for audio" got me thinking about using delay line memory in air to somehow make sounds... basically what you "store" in the delay line is what you are hearing at any one moment, if I understand how it works.

    Andy Geppert12:42 PM
    @Ken Berkun Another reason to like jukeboxes in my mind. Another member, Joe Watson, shared that jukebox usage with me.

    Ken Berkun12:43 PM
    I don't know if this is the exact model I had, but it looked a lot like this:

    Usagi Electric (David)12:43 PM
    @Andy Oliver This sounds really similar to the feedback loops some artists use (I'm thinking specifically of Mick Gordon). They play a sine wave out a speaker into a microphone that creates a slight delay (and a boat load of distortion)

    Andy Geppert12:43 PM

    Muth joined  the room.12:43 PM

    anfractuosity12:43 PM
    @Andy Oliver that sounds intriguing, probably not what you mean, but you can get a thing for guitars that is like a big spring, that acts like a delay line for audio iirc

    morgan12:44 PM
    the spring is usually used for reverb

    Andy Oliver12:44 PM
    @Kelly Heaton it's about 59 olympic pools full of hand-woven core memory BTW

    Andy Geppert12:44 PM

    1 MB

    Download File

    Andy Geppert12:45 PM
    @Kelly Heaton Have you see this core memory quilt work?

    anfractuosity12:46 PM
    ah so it is @morgan

    Tony Robinson12:47 PM
    Thanks so much @Andy Geppert - I have to go but it has been very inspirational. Good luck, I'll enjoy following your progress.

    Kelly Heaton12:47 PM
    @Andy Geppert I have not seen it work -- thanks for bringing the project to my attention!

    And 59 olympic pools full of hand-woven core memory sounds like a world heritage site for sure. Great art installation for the desert: go visit the pyramids, then hop over to the core memory pools...

    Andy Geppert12:48 PM
    @Usagi Electric (David) Thanks for the tip on Jerry Walker's videos - will check that out later. Ham's use ferrite that is not readily magnetizeable, and that is different from the kind in core memory. I don't know the technical terms for the differences.

    Andy Geppert12:48 PM
    @Tony Robinson Thanks for being a part of the conversation. Fun stuff.

    anfractuosity12:49 PM
    oh that's very interesting re. there being different types of ferrites that aren't magetisable

    Usagi Electric (David)12:49 PM
    Copy that! Jerry does excellent videos, but sometimes his voice is a little too calm and I fall asleep, haha.

    Andy Geppert12:49 PM
    @Usagi Electric (David) I have not experimented with other forms... yet.

    Usagi Electric (David)12:52 PM
    That's fair enough, vintage memory is a rabbit hole of epic proportions

    Dan Maloney12:52 PM
    Rabbit, lol

    Ken Berkun12:52 PM
    I don't see this mentioned, but Ken Sherrif did a terrific series on the Apollo guidance system that use core memory "ropes", even doing Bitcoin mining: (sorry...

    Read more »

  • Hack Chat Transcript, Part 1

    Dan Maloney11/03/2021 at 20:14 0 comments

    Dan Maloney12:00 PM
    OK folks, let's start it up. Welcome to the Hack Chat, I'm Dan and I'll be moderating along with Dusan as we welcome Andy Geppert to talk about retro memory technologies.

    Welcome Andy! Can you start us off with a little about how you got interested in this stuff?

    Nicolas Tremblay12:00 PM
    better than the old 9 and something

    broswell joined  the room.12:01 PM

    Dusan Petrovic12:01 PM
    Hi Dan, Andy!

    Usagi Electric (David)12:01 PM
    Howdy Dan and Andy!

    Andy Geppert12:01 PM
    Hi everyone! I appreciate the opportunity from Dan to be a Hack Chat host on the topic of retro memory! I enjoy design and building electromechanical stuff. In the last several years I have gotten into retro computing and some of the technologies that are intertwined with retro computing. I think core memory is fascinating and that extends to pretty much anything involving magnets. Three years ago, I was looking for a way to explore core memory in a more tangible way, and I found it with my interactive core memory project. It’s been a lot of fun to learn, experiment, and design something that others will have an opportunity to enjoy. That project was substantially inspired and encouraged by people in the Hackaday community. I’m guessing a few of you supportive folks are here in the crowd! My dive into core memory has also opened up learning opportunities around all sorts of other kinds of memory that I didn’t know about (like FeRAM or FRAM). I look forward to learning more as we chat away on these topics. Feel free to share any of your retro memory experiences you have.

    broswell12:02 PM
    I am interested in building a way to visualize delay line memory for our museum visitors

    Andy Geppert12:03 PM
    Regrading floppies, still made, I can't find it... but I thought I read an article on Hackaday recently about a place in North Dakota still making the media?

    anfractuosity12:03 PM
    oh interesting thanks, will try googling north dakota too then

    Kelly Heaton12:03 PM
    Hi Andy, thanks for hosting this chat. Your work with core memory is beautiful!

    Dan Maloney12:05 PM
    In case you missed it:

    Dan Maloney12:05 PM


    Core 64: Interactive Core Memory Badge

    Draw with a magnet directly IN CORE MEMORY! Many people may have heard of core memory (most recently with the buzz surrounding the Apollo Guidance Computer) but few have experienced it. This project enables interaction and education using core memory that is unexpectedly engaging with the door wide open for more exploration.

    Read this on Hackaday

    Kelly Heaton12:05 PM
    Do you know of anyone (or have any ideas) for visualizing the electromagnetic patterns in core memory? Especially video would be really cool -- to observe how the electromagnetic field changes?

    Andy Geppert12:05 PM
    @broswell That's good project to ponder! This might inspire you, as it did me:

    broswell12:05 PM
    Thanks. I'll take a look

    Andy Geppert12:06 PM
    @Kelly Heaton Thank you! I would have never guessed I'd be weaving electronics in my middle-age years. ;)

    Dan Maloney12:06 PM
    My guess is that you *could* do it with some iron filings, but I doubt you'd *want" to do it that way

    anfractuosity12:06 PM
    Have you seen the piezo delay lines they used to use in TV apparently on a sheet of quartz i think

    Tony Robinson12:07 PM
    I have many TV delay lines - never wirred them up yet!

    Tony Robinson12:07 PM
    How hard is it to get all the currents right? I've always been put off by the 'half doesn't do anything, but double it and it flips'? That seems really tight to me. I'd love to build core but am frighted by the tollarances.

    Usagi Electric (David)12:08 PM
    Hi Andy! I'm not sure if you've seen Jerry Walker's videos, but he had a series on core memory recently. In his series he mentioned that core memory needs to use very specific ferrite cores, otherwise it doesn't quite work right. Have you tried...

    Read more »

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