Are there alternatives to binary data storage, and is there any appeal of alternatives

[septimus]

@jezzaOZ

From the efficiency of storage point of view, trinary is more efficient than binary.

I can’t remember the exact derivation but base e (2.71828…) is the most efficient. Translating to the integer world the closest value is 3 not 2.

A representation that allows one of S symbols will carry log(S) information. If the cost is proportional to S then S=2 and S=4 are tied for 2nd-place among integers for efficiency. S=3 is almost 6% more efficient than S=2. (And impossible(?) S=2.71828 is slightly more efficient still.)

BUT, that assumes that cost is proportional to S. This is clearly true in some simple cases (for example, a station that transmits a single constant-power sine wave will have S proportional to its FCC-allotted bandwith) but is it true in many important examples?

A flip-flop-flap circuit requires significantly more than 1.5x the hardware of a flip-flop circuit, I think.

[jezzaOZ]

@septimus

A flip-flop-flap circuit requires significantly more than 1.5x the hardware of a flip-flop circuit, I think.

Many GNU comparison functions have trinary return codes. -1, 0, and +1. 0 is a match and -1 and +1 indicate the direction of a mismatch

[davidm]

@jezzaOZ

Many GNU comparison functions have trinary return codes. -1, 0, and +1. 0 is a match and -1 and +1 indicate the direction of a mismatch

I’m pretty sure that that’s done at the software level rather than the hardware level. It’s not actually a hardware level compare opcode.

[leahcim]

@jezzaOZ

Many GNU comparison functions have trinary return codes. -1, 0, and +1. 0 is a match and -1 and +1 indicate the direction of a mismatch

In a lot of places the contract is that any negative number indicates “less than”, while any positive number indicates “greater than”, which allows a comparison between integers to be implemented efficiently as “return x - y”.

But that’s all done on a binary substrate.

[robert_columbia]

@JWT_Kottekoe

To address another part of the OP, biology does use base 4. There are four distinct nucleotides in DNA and RNA, each coding for two bits. There is also redundancy, both in the genetic code (64 codes map to about 20 amino acids) and, in DNA there is a second strand with the identical information in complementary form…

For an interesting SF take on the idea of humans being base-4 computers, read James Hogan’s “Silver Shoes for a Princess”.

[Mangetout]

A few years back, there was a guy who claimed to be able to encode absurdly high volumes of data in the form of coloured geometric shapes printed on paper (I think it was hundreds of GB per page). Fairly sure it was a scam or at least never came to fruition.

[Digital_is_the_new_Analog]

@andrewm

Differential signaling is for noise resistance - by measuring the voltage difference between a pair of conductors, any voltages induced by interference will affect both equally and not influence the difference. Differential signaling can be digital or analog. Do you have an example of a differential protocol using multiple discrete levels?

I’ve seen it when my hardware team was doing ethernet testing.

From Wiki:

A 100BASE-TX transmitter sends three differential voltages, +1 V, 0 V, or −1 V.[10]

1000BASE-T uses all four pairs bi-directionally and the standard includes auto MDI-X; however, implementation is optional. With the way that 1000BASE-T implements signaling, how the cable is wired is immaterial in actual usage. The standard on copper twisted pair is IEEE 802.3ab for Cat 5e UTP, or 4D-PAM5; four dimensions using PAM (pulse amplitude modulation) with five voltages, −2 V, −1 V, 0 V, +1 V, and +2 V[11] While +2 V to −2 V voltage may appear at the pins of the line driver, the voltage on the cable is nominally +1 V, +0.5 V, 0 V, −0.5 V and −1 V.[12]

It looks kinda ugly on a scope.