Since this is a Computer Science forum now i thought i'd post this impractical yet interesting take on data transfer.(adsbygoogle = window.adsbygoogle || []).push({});

If machine A has to send n bits over to machine B, and A knows the clock speed of B, rather than sending the n bits, A can instead always send two bits bit-1 and bit-2. B calculates the delay between the arrival of bit-1 and bit-2 (in B's clock cycles) which gives a number whose bit representation is the data that A sent.

So if A wanted to send a 5-bit string to B, for example 10011 (which is 19 in decimal) and knowing that B's clock speed is 1Ghz, A would send two bits, the second one being sent 19 billionths of a second after the first. B receives the two bits, computes the delay (which amounts to 19 computer cycles) and knows that A sent the value 19, or 10011.

This isn't practical for a many reasons, networks have long and largely variable delays (bits could take different routes, through faster or slower routers and shared mediums). But it's interesting, i think, that we can transmit any quantity of data between two machines using only 2 bits, given enough time (exponential time actually, with respect to the number of bits that need to be sent, which makes this completely impractical since just 50 bits would take forever, literally).

What's happening is actually that, if we were to look at the two bits in traffic, we'd see that they are separated by a distance d at all times. The value of d in binary is the data being sent. So we're not breaking any rules, physically there is a valid encoding of the data, it's encoded in a distance.

It's the same idea as encoding data in a long shoe lace, for example. We can take a long shoe lace and cut it to a size s where s in binary is the data we want to store. Or, instead of a shoe lace, we can take two baseballs and throw them into the air, one after the other. The amount of time between when the two baseballs hit the ground (in some time unit) gives the encoded data. By delaying the throw of the second ball, we can encode as much data as we want, without the need for a storage medium.

We can also choose to split the data we want to send into groups. For each group we would use the two-bit technique. If we do this we can obtain a process which enables us to send n bits from A to B, by sending only (1+n/logn) physical bits and waiting a total of (n^2/logn) clock cycles.

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# Low Bandwidth Networking

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