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One quantum transition makes light at 21 cm

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Re: One quantum transition makes light at 21 cm

#43
post #9

Earlier quoted context omitted.

It's ultimately what killed having a memory controller on the northbridge of a motherboard. Having the CPU talk to a separate chip to ultimately talk to the RAM simply added too much latency into the entire process.

And it may end up causing CAMM2 to end up being the next standard. The physical layout of the chips on the board means the traces can be shorter - leading to lower latency and higher stability.

I really hope CAMM2 takes off. It'd be a rare standard that could be used for both laptops and desktops. Having upgradable memory in a laptop again would be great. Using the same standard a desktop would make it easy to find sticks as time goes on.

Re: One quantum transition makes light at 21 cm

#44
post #2

I had a CS professor that used to hold up a length of string roughly that length and talk about how that is how far a bit of data can travel at the speed of light during a clock cycle or something. Honestly don't remember the point he was trying to make.

The point of how fast computers are, and why you need to make them smaller to make them faster. Think about the bus between the CPU and GPU, not much shorter than that. Information cannot travel faster than the speed of light, so there is a hard constraint on how quickly the GPU can respond to commands. The same is true for RAM and even within the CPU, signals take time to propagate across it. The total length of your circuitry for a single instruction can't be longer than 21cm if that's how far light travels.

Re: One quantum transition makes light at 21 cm

#45

> precisely 21 cm Imprecise use of "precise" in the strapline. According to https://en.wikipedia.org/wiki/Hydrogen_line the best measurement of it so far is 21.106114054160 +/- 0.000000000030 cm

Would have been odd if it had magically matched the arbitrary distances we use in the metric system. It's not that 1m is in any way a "natural" distance that was chosen for anything but practical reasons.

Re: One quantum transition makes light at 21 cm

#46

> precisely 21 cm Imprecise use of "precise" in the strapline. According to https://en.wikipedia.org/wiki/Hydrogen_line the best measurement of it so far is 21.106114054160 +/- 0.000000000030 cm

Yes that bugged me too. If you replace 'precisely' with 'approximately' everywhere in the article it becomes much improved ;)

Re: One quantum transition makes light at 21 cm

#47
post #37

> precisely 21 cm Imprecise use of "precise" in the strapline. According to https://en.wikipedia.org/wiki/Hydrogen_line the best measurement of it so far is 21.106114054160 +/- 0.000000000030 cm

That not just imprecise usage of that term; it’s completely incorrect. The correct term would be its exact opposite, “approximately”.

The exact opposite would be ”imprecise” or ”inaccurate”

Re: One quantum transition makes light at 21 cm

#48
post #38

Earlier quoted context omitted.

How many inches is that

It is 21.1061… cm worth of them. Fun fact, your computer is really good at answering this question for you. So is (say) Google Search.

Or an LLM, or even just using MacOS spotlight search autocompletes "21cm how many inches " to the right answer.
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