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Comment by tocs3 | Hacker News Reader

I have been thinking about this for a long time. Thanks for the link.

The biggest advantage of character-based encodings is that they can be decoded by humans (as opposed to dot-based encodings), which means that you don’t need a camera or a scanner to recover the data.

This is an interesting point. In our post apocalyptic future scholars will be using their quills to translate archives of these (in my imagination anyway). Of course they would have to translate into binary and then into human chars.

I can imaging they will be sad they cannot listen to the mp3's.

Adding color allows on to code more information per dot (3x more with three colors).

Is this right? Wouldn't it be base-3 encoding? Three bits of binary can count to 8. Three trits of base three can count to 27. Color has all sorts of disadvantages but maybe a much greater payoff (unless I m mistaken).

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If a pixel can be printed with no colors (white), cyan, magenta, yellow, cyan and magenta (blue), magenta and yellow (red), yellow and cyan (green), or all three inks (black), that's 8 colors, 3 bits per pixel, not just 3 colors. Typically laser and inkjet printers do more or less work like this, but also have a fourth ink, which is black.

I am very skeptical of this idea that people will be able to write but unable to produce useful digital computers. Computers are a mathematical discovery, not an electronic invention. Electronics makes them a thousand times faster, but a computer made out of wood, flax threads, and bent copper wire would still be hundreds of times faster than a person at tabulating logarithms, balancing ledgers, calculating ballistic trajectories, casting horoscopes, encrypting messages, forecasting finances, calculating architectural measurements, or calculating compound interest. So I think automatic computation as such is likely to survive if any human intellectual tradition does.

I am very skeptical of this idea that people will be able to write but unable to produce useful digital computers.

I agree. When I first saw the post and the mention of humans in the reading end of the loop, I though "maybe there is a scifi story here". Hard to imagine a scenario that left humans but not many artifacts except caches of paper (or other "printed" media). Maybe a remote tribe of uncontacted people (or another species altogether) inherit the Earth after a modern world apocalypse kills off everyone in the technologically more advanced world.

A civilization starting from scratch would still need to develop a fair bit of math and tech/science sophistication before understanding and starting to use artifacts left behind. In particular optical/color on paper scanners would have been difficult before the 20th century.

> In our post apocalyptic future scholars will be using their quills to translate archives of these

Imagine tomes of programming lore, dutifully transcribed by rooms of silent scribes, acolytes carrying freshly finished pages to and fro, each page beautifully illuminated wih pictures of the binary saints, to ward off Beelzebug.

See also: the first part of A Canticle for Leibowitz.

Thank you for this. I had never heard of this book, but it sounds intriguing, and my local bookstore happens to have a copy.

The inhernt errror resilience in charactre encoding of human languige is also an intersetnig point.

This is why, when pulling wire, I write out the numbers longhand on the end of each one. "SEVENTEEN" is a lot more smudge-resistant and unambiguous umop-apisdn than "L1".

> Is this right? Wouldn't it be base-3 encoding? Three bits of binary can count to 8. Three trits of base three can count to 27. Color has all sorts of disadvantages but maybe a much greater payoff (unless I m mistaken).

In this case they're not directly using the color to store information, they just have three differently colored QR codes overlayed on top of each other. With that method you can use a filter to separate them back out and you've got three separate QR codes worth of data in one place. The way they're added ends up using more than just three colors in that example.

If you were truly to use colored dots to store binary information without worrying about using a standard like QR, I think you'd be going from base-2 (white and black) to base-3 (red, blue, green) or more likely base-4 (white, red, blue, green) or even base-8 (if you were willing to add multiple colors on top of each other) in which case yeah you'd have way more than just 3x the data density.

>this case they're not directly using the color to store information, they just have three differently colored QR codes overlayed on top of each other. With that method you can use a filter to separate them back out and you've got three separate QR codes worth of data in one place. The way they're added ends up using more than just three colors in that example.

That's only true if you can print and read colors in a higher resolution/don't destroy information at 3x the density with color, I'm not sure if that's generally true.

>If you were truly to use colored dots to store binary information without worrying about using a standard like QR, I think you'd be going from base-2 (white and black) to base-3 (red, blue, green) or more likely base-4 (white, red, blue, green) or even base-8 (if you were willing to add multiple colors on top of each other) in which case yeah you'd have way more than just 3x the data density.

Base 8 is exactly 3x the data density. (Log(8)/log(2))

CMYK makes more sense for printing, e.g. https://en.m.wikipedia.org/wiki/High_Capacity_Color_Barcode

I think for that use-case (copying by quill), just writing plaintext from the start would be the move

Adding 3 colors would make it base 5 (BW+rgb) and give log(5)/log(2) or about 2.3 times the information per dot.

2 dots at 5 possibilities each gives 25 (5^2)

2 dots at 2 possibilities each gives 4 (2^2)

They only diverge from there. Or am I doing my math wrong?

Information is ~log(possible states) according to Shannon.

Log(25)/log(4) is 2.3. Among other things this definition has the nice property that two disks/pages/drives/bits together contain the sum of the capacities instead of their product.

To expand if it helps intuition: As data data density grows, the largest representable number grows exponentially.

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