I realise (/think?) that CPUs essentially treat two different voltages as a 1 or 0, but what stops us from using 3 or more different voltages? Wouldn’t that exponentially increase the CPU’s throughput by allowing for decisions with greater than two outcomes to be calculated in one cycle? This would presumably mean that a LOT of stuff written for base 2 would need to be updated to base 3 (in this example), but I can’t imagine that’s the only reason we haven’t done this.
I feel like I’ve explained that poorly, but hopefully you get the gist.
In: 12
A lot of effort had gone into getting them to work in base 2.
Earlier, things were a bit more open as standard ideas were less solid. The Soviets did a lot of work with base 3 computers using a concept called balanced ternary. Analogue electronics at the time commonly used voltages above and below zero – so when it came to digital circuits why not use zero, negative and positive.
The soviet approach was to use base 3 but with symbol for +, 0 and -. So for example the number eleven would be stored as ++- (9 + 3 – 1).
One of the advantages of the ternary approach was that it drastically reduced the number of transistors needed compared to a binary system. Ternary computers wer consistently more powerful than equivalent binary computers.
The problem came with defining the basic operations, especially logic. This made ternary circuits more difficult to design, build and test.
Eventually, theoretical improvements in binary circuit design won out – it was easier to teach circuit design and it was easier to be sure your circuit was right (including design of computer programs to check your circuit design) for binary. The increased design effort for ternary wasn’t worth it.
When chips with thousands of transistors came, the lower number of transistors in ternary, which was the only real advantage left, was gone.
Latest Answers