191–200 of 233 posts
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> IMO, The fact that it's only 38x the minimum is MIND BLOWING. It's like if someone made a car that drives at 1/38th the light speed.
For anyone too lazy to math, its a car that can go: 28.4 million km per hour (i.e. 17.6 million miles per hour) I wonder how much that speeding ticket would cost. Disclaimer: Assuming the one-way speed of light is 300k km/s
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That price is more than a decade out of date. Helium has been about 10x that the past half decade. I used to pay about $3,000 per 100L dewar a few years ago. Sounds like that price was still common in 2020: https://physicstoday.scitation.org/do/10.1063/PT.6.2.2020060... Plus, liquid helium is produced as a byproduct of some natural gas extraction. If you needed volumes beyond that production, which seems likely if yo…
That's the cost for one-time use of the helium. If you're running a liquefier the cost is much lower, since you're recycling the helium, but it still "costs" ~400W to cool 1W at 4K.
Initial cost is high but running it should mostly just incur energy costs if it’s well designed.
> We use a logic primitive called the adiabatic quantum-flux-parametron (AQFP), which has a switching energy of 1.4 zJ per JJ when driven by a four-phase 5-GHz sinusoidal ac-clockat 4.2 K. The landauer limit at 4.2K is 4.019×10^-23 J (joules). So this is only a factor of 38x away from the landauer limit.
> The landauer limit at 4.2K is 4.019×10^-23 J (joules). At room temperature.
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Considering that many modern interfaces are somehow less responsive than ones written over 20 years ago even when running those programs on period hardware , I feel certain that you are right.
This is a very complex topic and there's a bunch of reasons for that. And no, software efficiency isn't even the main factor. Not even close. Just a few pointers: polling on peripherals instead of interrupts (i.e. USB vs. PS/2 and DIN) introducing input lag, software no longer running in ring-0 while being the sole process that owns all the hardware, concurrent processes and context switches, portability (and the req…
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>Not that that's necessarily a bad thing, if we're getting more than proportionally more utility out of the processors The trend seems to be that we get only a little bit of extra utility out of a lot of extra hardware performance. When the developer upgrades their PC it's easier for them to not notice performance issues. This creates the situation where every few years you need to buy a new PC to do the things you a…
> The trend seems to be that we get only a little bit of extra utility out of a lot of extra hardware performance. "hardware giveth, and software taketh away"
Andy Grove and Bill gates
Footnotes:
[1] Including non-conductors... but you need a lot of voltage!
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There is a Veritasium video really fun to watch which exmplains with examples why you cannot measure one way speed of light: https://www.youtube.com/watch?v=pTn6Ewhb27k
Yes! In uni I had this idea for a program that would triangulate where lightning struck by having multiple computers across campus listening for thunder, then measuring the difference in arrival times of the thunder. Like GPS in reverse. Soon I realized I’d need the computers’ clocks to be as in-sync as possible, which in turn requires one-way latency calculations. I spent an hour diagramming with pencil and paper un…
Latency caused by the speed of light is a tangible and impactful factor in our lives!
It's amazing that something so incomprehensible (3x10^8 m/s) can actually be experienced.
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It seems likely that the more efficient our processors become, the larger share of the world's energy we'll devote to them [0]. Not that that's necessarily a bad thing, if we're getting more than proportionally more utility out of the processors, but I worry about that too [1]. [0] https://en.wikipedia.org/wiki/Jevons_paradox [1] https://en.wikipedia.org/wiki/Wirth%27s_law
> Not that that's necessarily a bad thing, if we're getting more than proportionally more utility out of the processors, but I worry about that too I have two points to comment on this matter. Point 1: The only reason I would worry or be concerned about it is if we are using terribly-inefficient programming languages. There are languages (that need not be named) which are either 3x, 4x, 5x, 10x, or even 40x more inef…
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>Imagine how programming and operating systems might look in a world where processing power is 80x cheaper. So like 2009 compared to 2021? Based on that, I'd say even more inefficient webshit.
Considering that many modern interfaces are somehow less responsive than ones written over 20 years ago even when running those programs on period hardware , I feel certain that you are right.