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Comment by elvinyung | Hacker News Reader

This reminds me of core rope memory [1], AKA "little old lady" memory, which was literally a ROM that was manually woven.

[1] https://en.wikipedia.org/wiki/Core_rope_memory

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Which in turn reminds me of South American 'quipu': https://en.wikipedia.org/wiki/Quipu

On the topic of cool old memory technologies, see also mercury delay line memory, which involves a cylinder of mercury into which you transmit pressure waves to encode information, and to read it back you wait for the particular offset in time when the beginning of the data you need is reflected back to you: https://en.m.wikipedia.org/wiki/Delay_line_memory

Sounds similar to surface acaustic wave filters and delay lines, which were e.g. commonly used in televisions (to make the color signal of the preceding line accessible while drawing the next line, it needs to be delayed by a line (64 µs). These work by turning the electrical signal into a mechanical strain wave travelling mostly on the surface of the substrate, where it can be filtered by mechanical means (think tuning forks, but etched into the surface) or simply delayed by the path length. The "receiving" end then turns the mechanical wave back into electricity.

> By the standards of the time, a relatively large amount of data could be stored in a small installed volume of core rope memory: 72 kilobytes per cubic foot, or roughly 2.5 megabytes per cubic meter

Wow, I'd never heard of this 'rope' memory before - incredible!

What were the actual ropes themselves made of? Just standard rope materials?

Copper.

Edit: I found a neat video: https://youtu.be/X0WnddW5gZI

I’ve been programming for nearly 30 years and today I just learned that “bits” was derived from BInary digiTS.

That’s an amazing video. Thank you for posting it.

Also, "pixels" is from "PICture ELements"

"pels" was an early designation.

It's still used among video codec discussions, especially with the MPEG group.

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