Reconfigurable Analog Computers

Ullmann to the rescue. We’re indifferent to analog computers like Detroit was once with electric cars.

The article mention EAI's SIMSTAR, a real software reconfigurable analog computer from the 1980s. Here's a description of how that worked.[1] This was pretty good. They had a crosspoint of FET analog switches to pass signals around, so they managed to do this in solid state, without relays. They had a M68000 as a control machine to set up connections. It all worked well enough to allow a real time man-in-the-loop simulation of the F-16 control system.[2] Just barely. The USAF paper says that the biggest problem was keeping the SIMSTAR analog computers alive.

Analog FPGAs have been made, downsizing this sort of thing to chip size. But not recently. The problems seem to be 1) lack of a use case, and 2) noise.

Analog computing is all about noise minimization. This is Not Fun.

There's interest in this stuff for neural nets, which do a lot of clipping and may be less noise-sensitive.

[1] https://www.analogmuseum.org/library/simstar_technology.pdf

[2] https://apps.dtic.mil/sti/tr/pdf/ADA189675.pdf

Love this idea. One use case is actually music synthesis as digital tools like supercollider are not that aurally satisfying while making analog circuits is tedious. Software controlled analog is a nice in-between. BTW I mean use case as in "this is cool, I would like to use it" not "bzillion users and a pile of money" ofc haha.

See also: Eurorack, FPAAs, Jumperless, Zoxnoxious (https://www.youtube.com/watch?v=LsGcW3EjFYo)