Analog computing may be coming back • Hacker News Board

Re: Analog computing may be coming back

#61

Post by jakedata » Tue, Jan 31, 2023, 3:51 PM UTC

jermaustin1 wrote: post #55

nanna wrote: post #29

Earlier quoted context omitted.

Depth of sound, long term storage, ease of navigation, there are lots of reasons people prefer vinyl that aren't based in nostalgia.

What do you mean by depth of sound? A vinyl record has a dynamic range of around 70db, where as a CD has a dynamic range of up to 144db, though in practice it is usually only 90-96db. Either way you shake that stick though, digital audio (uncompressed) has a much deeper sound. Even in the recording studio back in the days of vinyl pressings all ran on studio grade magnetic tape with a higher dynamic range (not by muc…

Often vinyl records are much more carefully mastered when compared to their CD counterparts. Many of us are survivors of the loudness wars. https://www.yoursoundmatters.com/vinyl-vs-cd-in-the-loudness...

Re: Analog computing may be coming back

#62

Post by krisoft » Tue, Jan 31, 2023, 3:53 PM UTC

pjerem wrote: post #34

giladvdn wrote: post #13

Earlier quoted context omitted.

Interesting analogy, and I see your point. What I'm trying to say is, we know that there's way to perform certain computations that's orders of magnitude more efficient than we've ever achieved. We have a working example of it. And yet, we choose to develop a wholly different technology, from scratch, that's unproven, instead of trying to emulate or understand what already have.

We are far from having a model of how the brain really works. Furthermore, i know it's a really common analogy but the brain is not really comparable to a computer. The brain is not programmable, it only have a single function which is "given x input, what output is more likely to keep the organism alive and well". It's a complex task, for sure. But that's not a computer. A computer is a machine on which you can run…

> The brain is not programmable

But that is not true, is it? You take a person and train him/her the right way and you will get a fighter pilot, or an equestrian or a poet. The difference between your fingers and the fingers of the finest goldsmith or cellist is thousands of hours of practice. And that didn't change their fingers, it reprogrammed their brain.

So yeah, you can't upload a new program to it with a USB port, but it definitely can be programmed.

Re: Analog computing may be coming back

#63

Post by jerf » Tue, Jan 31, 2023, 4:01 PM UTC

It seems to me that punters overly excited to declare that everything we've ever done up to this point is wrong and there's a new paradigm coming that will obsolete everything, as well as people being critical of the new thing, tend to miss a very important aspect of digital computation that will prevent analog computation from ever simply "taking over": Digital computation is essentially infinite composable.

It does not matter how many gates you throw your 1s and 0s through; they will remain ones and zeros. While floating point numerical computations carry challenges, they are at least deterministic challenges. You can build things like an SHA512 hash which can ingest gigabytes upon gigabytes, with the entire computation critically dependent at every step upon all previous computations in the process, a cascading factor of literally billions and billions, and deterministically get the exact same SHA512 hash for the exact same input every time.

This property is so reliable that we don't even think about it.

Analog computers can not do that. You could never build a hash function like that out of analog parts. You can not take the output of an analog computer and feed it back into the input of another analog computation, and then do it billions upon billions of times, and get a reliable result. Such a device would simply be a machine for generating noise.

Analog computing fits into the computing paradigm as another "expansion card". It may take isolated computations and perform them more efficiently. Perhaps even important computations. But they will always be enmeshed in some digital computer paradigm. Breathless reports about how they're "coming back" and coming soon and taking over are just nonsense. (I speak generally, this walled-off article may or may not have made such claims, I dunno.) So many things about how digital computers work that you just take for granted are simply impossible for analog computers, structurally; something as simple as taking a compressed representation of a starting state for your analog computer is something you need a digital computer for, because our best compression algorithms have the same deep data dependencies that I mentioned for the hashing case.

Useful, interesting, innovative, gonna make some people some money and create some jobs? Sure. Something we should all go gaga over? No more than a new database coming out. It's going to be a tool, not a paradigm shift.

Re: Analog computing may be coming back

#64

Post by Drunk_Engineer » Tue, Jan 31, 2023, 4:05 PM UTC

frafra wrote: post #20

singularity2001 wrote: post #16

Analog will likely come back but for other reasons: Neural networks don't require precise calculations and Hintons forward forward networks put into hardware would be several orders of magnitudes more efficient, even without photons. "AI inferencing is heavily dependent on multiply/accumulate operations, which are highly efficient in analog." If you know of any startup working on this let me know because I'd love to…

Almost one year ago, Veritasium interviewed https://mythic.ai/ in one of his videos on YouTube: https://youtu.be/GVsUOuSjvcg?t=898 .

They ran out of money last year.

Re: Analog computing may be coming back

#65

Post by jefurii » Tue, Jan 31, 2023, 4:14 PM UTC

Analog computing has been used by musicians for awhile now.

Synthesizers are basically analog computers. Bob Moog was an engineer whose genius was figuring out how to connect keyboards to lab equipment and how to hide enough of the guts to make the gear approachable to musicians. West Coast synthesists like Buchla took the opposite approach of appreciating the sound of analog computing for what it is.

Synthesizers tried to hide it for awhile behind layers of user interface, but especially with the Eurorack boom of the last decade or so you can really see that synthesizers are simply specialized analog computers. Lots of synth modules openly use the same terminology as analog computing: filters, amplifiers, multipliers, low-pass gate, sample and hold, sequencer, etc. Musicians like Hainbach use actual test equipment in their music.

Guitar effect rigs are also basically analog computers. They're just not used for numerical computation.

update: The Signal State is a Zach-like game where you solve puzzles by programming analog computers; in was inspired by Eurorack synthesizers.

Re: Analog computing may be coming back

#66

Post by Pet_Ant » Tue, Jan 31, 2023, 4:23 PM UTC

jakedata wrote: post #61

jermaustin1 wrote: post #55

Earlier quoted context omitted.

What do you mean by depth of sound? A vinyl record has a dynamic range of around 70db, where as a CD has a dynamic range of up to 144db, though in practice it is usually only 90-96db. Either way you shake that stick though, digital audio (uncompressed) has a much deeper sound. Even in the recording studio back in the days of vinyl pressings all ran on studio grade magnetic tape with a higher dynamic range (not by muc…

Often vinyl records are much more carefully mastered when compared to their CD counterparts. Many of us are survivors of the loudness wars. https://www.yoursoundmatters.com/vinyl-vs-cd-in-the-loudness...

Ugh, this frustrates me. You are just saying that the _mix_ put on vinyl is better than the mix put on CD. That same mix put on CD would be even better due to higher fidelity of the format. Vinyl is a strictly worse format... unfortunately it's also an easier source of better mixes.

Re: Analog computing may be coming back

#67

Post by orbifold » Tue, Jan 31, 2023, 4:35 PM UTC

adgjlsfhk1 wrote: post #57

orbifold wrote: post #48

Earlier quoted context omitted.

Visible light and near ultra-violet light has a wavelength ~400-800 nm, current gen transistors have a pitch of ~40 nm. This gets worse because scaling is actually either quadratic (2d) or cubic (future 3d integration). So we are talking about 100x to 1000x worse spatial scaling disadvantage at the moment. The only redeeming quality of light is wavelength multiplexing, but that is only useful for a subset of applicat…

100x loss in density isn't actually necessarily a problem. Optical systems have potential for much higher clocks (since there's so much less heat), and the actual logic on a cpu is tiny. If you can get 50ghz clocks, you can lose a lot of density and still win out (I'd take 10x single core perf over 10 cores any day of the week).

Even optical computing needs lots of standard electronics for storage etc. as you point out these consume most of the area, so we are talking about something that consumes 100x more area for a function which is not the main energy expensive thing in traditional computers anyways, memory and communication make up at least 1/3 of the energy budget, which doesn't go away by making the rest optical.

In fact reprogramming the optical non-linearities typically is much slower and energy intensive than retrieving and flipping some bits. Which makes non-static non time-multiplexed computation extremely slow compared to whatever the "best" case static scenario is.

Re: Analog computing may be coming back

#68

Post by vctrnk » Tue, Jan 31, 2023, 4:37 PM UTC

zozbot234 wrote: post #22

Analog computing sucks. It's inherently sensitive to noise and random variation in your devices that's basically ubiquitous with modern chip-making processes. Digital electronics actively reject noise at every step in a computation, albeit at the cost of wasting energy in the process. With analog, a more complex computation becomes exponentially harder.

What if randomness is desirable? What if volume of signals to process is so humongous, some (controlled) noise is actually beneficial? Analog computing sucks at processing digital signals, the same way digital sucks at finely approaching the analog domain. Even at light-speeds there's only so much a bunch of zeroes-and-ones can do.

Re: Analog computing may be coming back

#69

Post by lambdaxymox » Tue, Jan 31, 2023, 4:46 PM UTC

It's interesting that the black art of analog design never really goes away even from computing. I was reading Geoffrey Hinton's "Mortal Computation" where he briefly speculated towards the end on low power (in watts used, not capability) neural networks being embedded in hardware via something like memristor networks. It makes me imagine neural networks being distributed as a template (i.e. a blob of XML describing the topology and the weights) and then the network weights get tuned a little different to each device or device model to get the best performance per watt out of them. Since every device is physically a little bit different from the next, in precision analog applications with discrete components the components have to be matched. This is often the case in assembling differential pairs in analog audio circuits. Similarly with the control system parameters with hard drives. Since each DC motor is a little bit different from the next, the control loop gets tuned at the factory to each drive. So in this case, the neural network gets matched to the circuit it's embedded in. Mortal computation indeed, each neural network becomes truly unique. I could be full of it, but it's fun to imagine at least.

Re: Analog computing may be coming back

#70

Post by Our_Benefactors » Tue, Jan 31, 2023, 4:58 PM UTC

Pet_Ant wrote: post #66

jakedata wrote: post #61

Earlier quoted context omitted.

Often vinyl records are much more carefully mastered when compared to their CD counterparts. Many of us are survivors of the loudness wars. https://www.yoursoundmatters.com/vinyl-vs-cd-in-the-loudness...

Ugh, this frustrates me. You are just saying that the _mix_ put on vinyl is better than the mix put on CD. That same mix put on CD would be even better due to higher fidelity of the format. Vinyl is a strictly worse format... unfortunately it's also an easier source of better mixes.

Not a vinyl purist, but the argument is that the same mix sounds different pressed into vinyl vs burned to disc because they reproduce the frequencies differently when read. You would have to engineer the CD mix differently to match the sound of the vinyl.