3 ms·
"Physical analogues of all the basic logic functions (AND, OR, NAND, XOR, NOR, NOT) should all be constructable." Trivially so. Electronic circuits are not int
by jerf 5y ago
"Physical analogues of all the basic logic functions (AND, OR, NAND, XOR, NOR, NOT) should all be constructable."
Trivially so. Electronic circuits are not intrinsically digital, nor are integrated chip components. They are intrinsically analog. We get digital behavior out of them by building and driving them in a certain way. The cost/benefits tradeoff on using these components digitally is so nice for us that we do it so often that we can forget this fact, but it is a fact. There are a number of chips that have analog components and behaviors in them; you can find a lot of them in sound synthesis, for instance, especially older ones like the SID chip ("The chip combines analogue and digital circuitry, that cannot be emulated with 100% fidelity even today." https://www.c64-wiki.com/wiki/SID https://www.c64-wiki.com/wiki/SID ).
gorgoiler, you are speaking as if you consider analog computing a subset of what digital computing can do, but it's actually the other way around. Digital computing is a subset of analog computing where we deliberately construct a digital computer out of what are still analog parts. Anything a digital computer can do, an analog computer can do, because it can simply function digitally for that portion but then incorporate other analog components. And as is often the case, when you really get down to it the line gets fuzzy... is the Commodore 64 an "analog" computer just because it had an analog part used in a particular set of ways? I think most people would say no... but it certainly wasn't 100% digital.
As I mentioned in another comment, I kinda think the video does a disservice by going too deeply into "analogical" vs. "analog". They've separated in meaning now. The people he shows at the end doing modern analog computers are, as far as I know, building things that look a lot more like a modern computer, except the requirement that all the components be driven by a clock signal and that all voltages stabilize before the next clock is loosened and they permit other analog behaviors of electronics to come in, allowing for programmable analog computers. They're not building things out of cogs with direct and obvious connections to underlying processes... modern digital computers are far better for those sorts of things.
- dredmorbius 5y agoRight. I'm thinking specifically of cases in which, say, a water-control system might utilise such elements, and just how complex they might get. This isn't my area, so I'm being conservative in statements. An electronic switch translates to a hydraulic valve. And a hydraulic valve is a direct analogue of a vacuum tube or transistor: an applied input delivers a controlled input. Often but not necessarily amplified --- there are cases where the input effort might be much larger than the output, in control or precision implementations. Mind: a valve itself might be water activated, in the sense of a small flow through one channel translating to a large flow in a controlled channel. One obvious example of this is the fantail of a post windmill, where any orientation of the mill's main sails outside the primary wind flow starts spinning the fantail which reorients the mill into the wind. See: https://upload.wikimedia.org/wikipedia/commons/6/65/Beebe_Windmill_Isometric_of_Machinery_Long_Island_NY.jpg https://upload.wikimedia.org/wikipedia/commons/6/65/Beebe_Wi... There are numerous cases of interlocks, many of which are mechanical. Some of these are through inherently fail-safe designs. A canal's locks, aeroplane doors, and airlocks all open such that they require pressure equalisation, preventing opening whilst the lock and channel are at different levels, or pressurised and depressurised regions are not at equilibrium. Shift-lever and starter interlocks require that brakes be engaged and vehicles in neutral to start, or shift from reverse. https://realpars.com/interlock/ https://realpars.com/interlock/ And I'm finding a few references specifically to mechanical control logic: "Mechanical Logic Devices and Circuits" http://www.nacomm09.ammindia.org/NaCoMM-2009/nacomm09_final_pap/R/RCA18.pdf http://www.nacomm09.ammindia.org/NaCoMM-2009/nacomm09_final_... (PDF) "PDF Pneumatic Logic & Controls - Parker Hannifin" https://www.parker.com/literature/Literature%20Files/pneumatic/Literature/Telepneumatic/PCC-4.pdf https://www.parker.com/literature/Literature%20Files/pneumat... (PDF) The second is a catalogue of available products based on pneumatic logic. One specific domain in which analogue / mechanical controls have been specifically discussed is for future Venus lander missions. Temperature and pressure profiles are too high for virtually all electronic systems (circuit boards, solder, and componentry would thermally degrade or melt). JPL have specifically explored the concept of a "clockwork rover", AREE (advanced rover for extreme environments) for a Venus or similar mission: https://www.jpl.nasa.gov/news/a-clockwork-rover-for-venus https://www.jpl.nasa.gov/news/a-clockwork-rover-for-venus
- credit_guy 5y agoAlso, all the domain of fluidics, such as https://en.wikipedia.org/wiki/Paper-based_microfluidics https://en.wikipedia.org/wiki/Paper-based_microfluidics
- dredmorbius 5y agoBeautiful, thanks!