Multigrain Timestamps Try Again For Linux 6.13 - Now With Less Performance Impact

[schmidtbag]

1. Metric system units are all based on Earth scale, then redefined in terms of universal constants. Complaint of Celsius being only useful on Earth is nonsense. You may as well abandon the metric time unit Second.

Fahrenheit is defined the same way too and therefore the same, so your point here is moot. Celsius is based on Kelvin, but that uses the Celsius scale.
I'm all for universal constants but having a scale that was once based on the boiling and freezing points of water that is then translated into universal constants without changing the scale really doesn't mean much in terms of its usefulness as a scale.

2. What temperature is bearable / comfortable varies among people.

Yes, which is why I said 75F is what most would regard as comfortable. Some people like it a bit warmer, some like it a bit colder, but on average, hardly anybody is going to complain about being in mid to low 70s. Think of it like the flavor of orange, which (last I heard) is the least disliked flavor of all flavors. It isn't ranked as a global top favorite, but just about everyone will at least tolerate it. 75F is the same - practically nobody would find that temperature untolerable, even if there are people who prefer to perpetually be a 65F or 85F.

3. The water freezing point and boiling point metric depends not on the sea level on Earth, but the atmospheric pressure at sea level on Earth. We built the International Space Station with such atmospheric pressure inside. We are going to build space stations and space colonies with such atmospheric pressure in the future. So even if human beings forget why 1 "day" = 86400 "seconds" and why are they this long but not longer/shorter in the far sci-fi future, we will probably still be very familiar with 1 atm. Maybe we will reverse the rationale and say 1 atm is the pressure such that water freeze in 0C and boil in 100C. Just like the joke of floppy disk become the "physical save button".

I knew someone was going to be pedantic enough to correct me about atmospheric pressure, but I didn't mention it for a couple reasons. First, it isn't entirely true, because it's not just the atmospheric pressure that matters but gravity:

https://phys.org/news/2017-03-unusual-fluid-behavior-microgravity.html

I haven't found anything regarding ice on the ISS, but I imagine water ice is still prone to disproportionately sublimate regardless of atmospheric pressure.
Second, specifying the atmospheric pressure still doesn't really change my point, because a large percentage of Earth's population is not experiencing 1atm. In fact, there are many large cities (hundreds of thousands to millions of people) in Asia, Bolivia, and Mexico that are well above 3000m, and many people encounter pressure-related struggles when coming from sea level to those places or vise versa. A comfortable atmospheric pressure is relative.

Anyway, as far as I'm concerned, units should only be created for one of two purposes:
A. Something that anyone can make intuitive sense of in any environment; preferably something that someone can reasonably estimate without a tool to measure with.
B. Something that is cleanly based on universal constants. So going back to Kelvin - that's almost good enough in that it's based on the Boltzmann Constant, but the amount of joules to define it is super messy. Wouldn't it be better if the scale was just 10⁻²³ rather than 1.380649×10⁻²³?

There are all sorts of SI units that are like this. The meter is a good example of this, where it too is an Earth-bound definition that was then assigned to a calculation of a universal constant to give the same number, at which point they could've just rounded it to a nice clean 1/300000000 instead of 1/299792458 (a 0.4% difference). Or, just create an all-new unit that would be even cleaner, like being 1/1,000,000,000 of the speed of light (which if I understand right is not too far off from 1 imperial foot, which is a reasonably useful length for everyday purposes).


</rant>

[billyswong]

Outside North America, almost nobody uses Fahrenheit. I look up how Fahrenheit was derived. It took "eutectic temperature of ammonium chloride brine" at 0F. Then it took human body temperature at 96F or 90F. Obviously the eutectic/freezing point is conditioned to be on sea level Earth too, . And there is the extra arbitrariness of why ammonium chloride and not others. It seems to be an approximation / emulation of sea salt / sea water. Sea salt / sea water composition is even more Earth-bound.

Soon after Fahrenheit's death, the Fahrenheit temperature scale was recalibrated to take freezing point of normal water as 32F, and boiling point of water as 212F. With such rescale, that "eutectic temperature" no longer matches 0F but becomes about 4F. Fahrenheit temperature scale become just an inferior legacy scale remained for people stuck with Fahrenheit and refuse to let their children adopt Celsius.

schmidtbag your 75F is no more intuitive than 24C. Maybe people in certain climate region on Earth care the freezing point of brine, but it is not a concern in other places, certainly not outside Earth. Freezing point of water is a lot more important globally as it is highly related to food preservation. Your 100F is human fever temperature, not normal body temperature.

Human average body temperature isn't even set in stone

https://www.scientificamerican.com/article/are-human-body-temperatures-cooling-down/

At the end of day, my point is Fahrenheit is LESS objective than Celsius, and LESS relevant to human daily lives. Can we design something better than Celsius if compatibility of human habits is not a concern? Maybe. But Fahrenheit definitely isn't the answer.