
The Land Before Binary - mbellotti
https://medium.com/@bellmar/the-land-before-binary-cc705d5bdd70
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Sniffnoy
Various corrections:

The article says that ternary uses exponentially fewer symbols (actually, in
further nitpicking, it says "bits" rather than "symbols") than binary, but
that's not correct. The decrease is just linear, by a factor of log_2(3).

The comment about subtraction being a lot easier doesn't really make a lot of
sense in light of 2's-complement notation; yes, it's a _tiny_ bit easier,
but... (the comments about sign bits also seem a bit out of place in this
light).

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__david__
The 2 of 5 encoding reminded me of "8 to 10" codes [1], which (as far as know)
is still in use by disk and tape drives. It's for a slightly different reason
than the 2 of 5 code but it's roughly the same idea.

[1]
[https://en.wikipedia.org/wiki/8b/10b_encoding](https://en.wikipedia.org/wiki/8b/10b_encoding)

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userbinator
...and those have been expanded to even bigger units:
[https://en.wikipedia.org/wiki/64b/66b_encoding](https://en.wikipedia.org/wiki/64b/66b_encoding)

Disk drives use a variant of RLL:

[https://en.wikipedia.org/wiki/Run-
length_limited](https://en.wikipedia.org/wiki/Run-length_limited)

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xellisx
Computers used to run on food...

~~~
Swenrekcah
And run for it on foot

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aib
> (FYI I’m going to reverse the conventional order so that the 2⁰ is the left
> most throughout this post)

Um, why would you break (or rather worse, _invert_ ) such a common convention?

> So 11 is 9+3–1.

...and not follow through, just two sentences later?

> [...] at which point the number 11 would be 2-0-1 (1+1+9).

Surely you mean 2+0+9 or 9+0+2?

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saagarjha
> POSTNET (the old barcode system the Post Office used to route mail up until
> a few years ago)

Oh, are these not in use anymore?

> The first group had two bits, one representing the number 0 and the other
> representing the number 5. The second group had five bits representing the
> numbers 0–4.

Sounds like an abacus to me…

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roywiggins
The Harwell WITCH used Dekatrons, which is a device that has 10 states and can
therefore store one decimal digit each.

[https://www.youtube.com/watch?v=vVgc8ksstyg](https://www.youtube.com/watch?v=vVgc8ksstyg)

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YeGoblynQueenne
And let's not forget Charles Babbage's Difference and Analytical Engines, both
of which were decimal-based.

And mechanical :)

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burlesona
This was a fun read, thanks for sharing!

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adamnemecek
Analog computers are even more interesting and I predict them to make a
comeback.

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bogomipz
Can you elaborate on why and where you believe they will make a comeback?

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adamnemecek
They can solve optimization problems better than digital computers. It's a
wholly different paradigm, for example the analog sorting algorithm has a
runtime of O(n). It's called spaghetti sort.

[https://en.wikipedia.org/wiki/Spaghetti_sort](https://en.wikipedia.org/wiki/Spaghetti_sort)

There used to be electric analog computers. I've been working on an analog
photonic computer (very theoretically so far) that I think could work.

Do you know how many electrons you move when you execute an instruction? It's
like on the order of 10^18. I might be able to get away with a couple of
photons.

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gitgud
Considering the high cost of developing new analogue hardware, wouldn't it be
cheaper to virtualize this on digital processors anyway?

Also there appears to be some dispute on the validity of "Spaghetti sort"

[https://en.wikipedia.org/wiki/Talk:Spaghetti_sort](https://en.wikipedia.org/wiki/Talk:Spaghetti_sort)

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adamnemecek
You won't get the gains from using only a few photons vs 10^18 electrons.

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yiyus
Is there a shortage of electrons I am not aware of?

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adamnemecek
You can pack 10^18 times more computation with the same size.

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gitgud
So the physical components could be smaller?

I guess my point is that unless you can take advantage of traditional chip
architectures or manufacturing, it may take an immense amount of effort to
develop something close to their component density.

~~~
adamnemecek
Amongst other yes. The main advantage is that you aren't dealing with metals
but with photonic crystals. These don't heat up so you can build a cubic meter
sized CPU theoretically.

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DrScump
I wonder if bi-quinary decimal influenced the later Packed Decimal (known as
COMP-3 in COBOL), which stored numbers in just over half the space of the text
equivalent (e.g. a 7-digit number would need 4 bytes).

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bbeonx
What's up with the binary representation of 11?

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daeken
They included 6 in the decimal representation of binary bits for some reason.
Outside of that, it's correct. This is a surprisingly common mistake, since
(2, 4, 6) is such a common pattern.

~~~
mbellotti
Well shit, thanks for noticing that. I've fixed it.

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Animats
Telephony used 2 out of 5 code extensively when passing dial digits around
within the system.

