Blast from the past!

[MRMILSTAR]

Here's a blast from the past. I've had this for a while. Anyone under the age of 50 may not recognize this. Before there was semiconductor RAM for memory, this is what computers used for fast working memory. This is called core storage. Each bit is stored in a tiny ferrite loop as a magnetic state. The ferrite loops are tiny, about 2 mm in diameter. These boards were assembled completely by hand!

Each loop has 3 wires passing through it for reading and writing data. The act of reading a bit actually erased it so the bit had to be re-writtten after reading! One advantage of core memory was that it was non-volatile.

This particular board contains 1600 ferrite loops thus it could store 1600 bits (200 bytes). It came from an IBM computer system. Not shown is the electronic drive and sense circuitry, made from discrete components, for reading and writing.

[Mads Barnkob]

I assume you have this at home, do you know what computer it came from and do you have any other related parts?

Core memory history is really interesting as it was a leap in computation speed due to faster access times to data and just the shear power consumption reduction durings development shows a will to make it cheaper, smaller and more usable in all kinds of machines besides large main frames. https://en.wikipedia.org/wiki/Magnetic-core_memory

[MRMILSTAR]

I do have it. My understanding is that it was used in the IBM 2821 control unit which was used to interface various peripherals to an IBM 360/370 computer. I don't have any other related parts. I would love to have a complete core memory module cube but they are very expensive. I would also love to have an IBM 360/370 control panel, but again, very rare and expensive.

My first computer was an Altair 8800 which I built from a kit in 1976. It was the very first personal computer. I sold it in the early 1980s for almost nothing. I wish that I still had it.

[klugesmith]

Very cool!  Let's see if I can find my own old core memory unit.

There are some modern core memory demonstrators that really work.  I wonder if their cores are old stock, made of material designed for data storage.  First hit of my search was corememoryshield.com.

[Hydron]

On the topic of old computers and core memory, I have really enjoyed following this youtube channel, especially the restoration of the Apollo AGC computer:
https://www.youtube.com/channel/UC3bosUr3WlKYm4sBaLs-Adw