Ternary Computing

eviltwinimposter writes: "This month's American Scientist has an article about base-3 or ternary number systems, and their possible advantages for computing and other applications. Base-3 hardware could be smaller because of decreased number of components and use ternary logic to return less than, greater than, or equal, rather than just the binary true or false, although as the article says, '...you're not going to find a ternary minitower in stock at CompUSA.' Ternary also comes the closest of any integer base to e, the ideal base in terms of efficiency, and has some interesting properties such as unbounded square-free sequences. Also in other formats."

Comments

Good Old binary and Floating Point.

[RGreen]

Ternary numbers are an interesting sidetrack and some similar techniques are used in fast chip-based systems to speed up adding (each bit also caries it's own overflow and sign bits, turning the classic serial add-with-carry into a more parallel operation).

It must be remembered that, for floating point numbers, base 2 is *the* most efficient representation, as argued in the classic paper "What Every computer Scientist Should Know About Floating Point Arithmetic" by David Goldberg. The deep understanding behind IEEE754 is a masterpiece of numerical engineering that is often overlooked, IMO.

astronomers used it since 80's

[Anonymous Coward]

As far as I know radio astronomers user 3-level data recording for their VLBI (Very Long Baseline Interferometry) data. One of the equipment was from JPL at Caltech lab. Their problem is to detect a weak signal in presence of strong noise. In this case, it doesn't make sense to do 8-bit digitization. Instead people do 1-bit, 2-bit digitization and average out many sample of data. They found that the recording efficiency was highest when they used 3-level digitization.
I myself worked on VLBI in the same lab but our machines were using 1-bit digitization (BTW, we used regular video cassette and somewhat modified VCR to record 7 GBytes on single 2-hour tape).

Gratuitous rain?

[leighklotz]

I am shocked, shocked to discover that a fundamental computer architecture explored in the 1950's, rejected as unworkable, and forgotten is in fact unworkable.

The feeling that this induces has no word in English, but in Japanese it's called yappari.

Don't get hung up on transistors.

[nels_tomlinson]

As long as we're turning the world on its ear, lets go all the way, and use triacs. We implement it (the tri-state gate, that is) like an inverter, more-or-less. These have two (non-linear ) on states plus off, and are just right for implementing an inverter. They'd probably be great for trinary logic, too.

I just dug out my old physical electronis book (Micro Electronics, by Jacob Millman, First edition), and can't find them in there, so here's a slightly less academic reference.

There might be some problems with trying to get the clock speed high enough to compete with the Intel/AMD marketing, though; it says that they can be triggered into conduction by high dV/dt.