THIS is what made analog “computers” obsolete, not their speed or their relative imprecision. Analog computers don’t in general use the same circuit modules for all calculations needing that particular function, so they are limited to the number of function modules they physically have. But in every analog “computer” I’ve seen, there are as many circuit modules as there are data paths required to complete a sequence of calculations. This is what allows digital computers to be substituted for each other – there is no calculation that can be done digitally that requires specialized circuits any Turing-complete computer can do any sequence of operations that any other Turing-complete computer can do. But in practice, digital computers use calculating circuits that are reconfigured on-the-fly, so that the same adder is used for all calculations requiring addition, the same multiplier is used for all calculations requiring multiplication, and so on. This is a rather rough definition of Turing-completeness. A computer is something that can perform a sequence of calculations, where that sequence can change depending on the results of previous calculations. I suggest that there’s really no such thing as an analog computer. The video shows a simulation of a Lorenz attractor running on THAT, slowed down 100x (by changing integrator settings) so that the simulation can run slow enough to be plotted by a mechanical X-Y plotter. We’ve covered many aspects of analog computing lately, like this story of restoration (and ultimately demise), a maritime astrolabe found in the Arabian Sea, and even an FPGA simulating an analog computing architecture. All that said, this is still a very interesting project, and definitely would be a Christmas present this scribe would be more than happy to unwrap. With that in mind, we can forgive that the community-focused learning tools are still being worked on. This is clearly work-in-progress and as they say on the main site, their focus is on chips for hybrid analog-digital computing, with a focus on energy-efficient approximate methods. We can’t find the PCB files either, but the assembly instructions show many bodge wires, so we guess they’re re-spinning the PCB to apply fixes before releasing them properly. Schematics are shown, albeit only images for now. Looking over the project Wiki there are a few application examples and some explanatory notes. After all, that pile of fatty grey matter between your ears is essentially a big analog computer, and that’s pretty good at problem solving. Now, there seems to be a move to shift back a little, with hybridized analog-digital approaches looking good for some applications, especially where precision is not paramount. At least, that’s their plan.įrom the 1970s onwards, digital computers became powerful enough to replace analog computers in pretty much every area, and with the increased accuracy this brought, the old analog beasts became obsolete overnight. Developed by Berlin-based Analog computer-on-chip specialist Anabrid, THAT is an Open Source analog computer you can build yourself (eventually) or buy from them fully assembled. But now, there is another option, (THAT) The Analog Thing. It’s pretty much a case of reading about them on these fine pages or perhaps looking at a piece of one behind glass in one of the more interesting museums out there. The analog computer of decades-gone-by is something many of us younger engineers never got the chance to experience first hand.
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