unconventional_computing.mdwn (2939B)
1 **Unconventional computing**, also known as **alternative computing**, 2 refers to computing with unusual methods. An unusual method may be e.g. an 3 unusual theoretical model or an unusual physical basis. The term 4 "unconventional computing" was coined in 1998. 5 6 Permacomputing is interested in expanding the lowest layers of the 7 technological possibility space, especially in order to develop computer 8 technology that better integrates with natural processes. This, along with 9 the strive for a greater [[technological diversity]], makes unconventional 10 computing techniques interesting from the permacomputing point of view. 11 12 **Fluidics**, using liquids or gases in place of electricity, is probably 13 the most mature alternative technological basis for computing. A fully 14 working fluidic digital computer, Flodac, was already built in 1964. Its 15 performance class was similar to relay computers (tens of cycles per 16 second), but it was mentioned in the paper that clock speeds up to 250 Hz 17 could be reached with similar but more compact circuitry. 18 19 Flodac-like logic gates are based on how fluids move within static 20 structures. So, unlike mechanical and relay computers, Flodac had no moving 21 parts. These structures could probably be printed with rather rudimantary 22 etching techniques or 3D printing, unlike semiconductor manufacturing that 23 requires extreme purity of the material and the etching process. 24 25 **Optical computing** is also quite mature. It has often been envisioned as 26 a way to stick to the [[Moore's law]] after the limits of silicon microchips 27 have been reached. The material constraints are different to those of 28 semiconductors, which may also make it an interesting option from the DIY 29 point of view. 30 31 Many unconventional computing technologies such as DNA computing are still 32 at a very early stage of development (as in "the addition of two small 33 numbers was succesfully demonstrated"). And even those who aren't are often 34 unsuitable for conventional digital computers. 35 36 Some unconventional computing techniques use living organisms. The use of 37 Physarum slime molds has been studied for a long time, and they can e.g. 38 solve shortest-path problems. 39 40 Quantum computing is probably the most hyped type of unconventional 41 computing because of the ability of a quantum computer to do an operation 42 "in millions of parallel universes at a time". 43 44 Today, integrated circuits are so dominant that even historically important 45 component technologies can be considered "unconventional". These include 46 fully mechanical parts (like those in mechanical calculators or the Zuse 47 Z1), relays (Z3), electron tubes (most 1950s computers), discrete 48 transistors (most early-to-mid-1960s computers), parametrons (some Japanese 49 computers mostly from the 1950s) and Symmag (the French computer CAB500 from 50 1957). 51 52 See also: 53 54 * [FLODAC - A pure fluid digital computer (Gluskin&al, 1964, PDF)](https://www.gwern.net/docs/cs/computable/1964-gluskin.pdf)