For Newtonian gravity at least, the gravitational force everywhere outside a sphere or spherical shell is exactly the same as if it was a point mass (and everywhere inside a spherical shell it is zero). Not sure if it holds exactly for general relativity.
I can't help but think that numbering all the devices was the wrong idea from the beginning. You don't want to talk to devices, you want to talk to (and offer) services. You probably need something like an AS number to make global routing efficient, but 32 bits would be plenty for that. A packet could be (destination AS, stream ID, encrypted( payload )) and DNS would give you a capability (destination AS, stream ID, keys) for a service. You send a packet to that stream asking to open a connection and providing a capability to reply (with a capability for the specific stream). Your network up to the AS level should have an opportunity to augment the stream IDs in whatever way is convenient for its routing. No one reveals any topology information, network neutrality and a degree of privacy is guaranteed at the protocol level, only really serious multipeer networks need to assign addresses above layer 2, and I think it would be reasonably easy to come up with an edges first incentive compatible transition plan (which is where ipv6 went wrong).
(This is of course an incomplete and poorly thought out proposal, you don't need to dogpile me about that.)
I'm currently using recursive page tables for the OS I'm working on, but I'm probably going to change that. There are lots of different address spaces for different processes and (with IOMMU) devices, and it's nicer to be able to modify any of them rather than only the current one. I am leaning toward just assigning 2 MiB of memory to page tables at a time and keeping a mapping for these (I don't want to map all physical memory in the kernel for security reasons).
There's a history of finding really strong correlations between vitamin D levels and (many kinds of) health, and then disappointing results for RCTs of vitamin D supplementation. There are lots of possible explanations of this, but it seems like a plausible one is that there are some good things sunlight does for you other than produce vitamin D. So I'm a little nervous about everyone eliminating all sun exposure and then taking vitamin D geltabs to compensate, even though sunlight carries some risks. (But obviously too much ionizing radiation is also a problem, and it sounds like most users of tanning beds are getting a lot of intense exposure)
I wonder how much correlation this has with exercise. Generally if you are getting good levels of sunlight, there is a good chance you are outside exercising, even if it's just walking.
After all, exercise is the undisputed God tier all-time winning champion of "Studies show that ______ is good for xyz."
I've taken up running because it's a way to get sunlight during the winter, I can run in shorts and a t shirt. I am very active, but I start getting a lot of anxiety if I don't get sunlight on my skin for a week or two.
UVA triggers the release of nitric oxide from the skin into the bloodstream. This causes blood vessels to dilate, lowering blood pressure and improving circulation.
Exposure to sunlight (or lack of it) affects our circadian rhythm and production of melatonin, which affects our sleep quality. Exposure to morning sun in particular is linked with better sleep quality, leading to better health.
> There's a history of finding really strong correlations between vitamin D levels and (many kinds of) health, and then disappointing results for RCTs of vitamin D supplementation.
This might just mean that bodies that are healthier in many other aspects are also better at managing their vitamin D stores which isn't all that surprising.
There are plenty of foods with vitamin D. You don't actually need to supplement it unless you're a vegetarian, you just need to actively include those foods in your diet.
The current argument I've read for why fair-skinned people even evolved near the North Sea and not anywhere else near the arctic is exactly that the Gulf Stream allowed a cereals-based diet rather than a meat based diet, which led to vitamin D deficiencies which caused problems in pregnancy, leading to people with fairer skin being the most likely to avoid those problems.
You definitely don't need to get your vitamin D from the sun.
I don't know where you read that fair skin is a diet adaptation and not a sunlight one, but that's wrong: fair skin is an adaptation to northern latitudes due to reduced sunlight. The majority of people of African descent in America are vitamin D deficient, but in Ghana — where there is much poorer nutrition, but more sunlight — they're not. Meanwhile, the majority of white Americans are not vitamin D deficient. [1]
Getting sufficient vitamin D takes 6x longer sun exposure for black people than for white people. [2] In northern latitudes that's pretty difficult.
My favorite one that I read about is mushrooms. If you grow them in the sun, some species allegedly acquire vitamin D. I am not sure how much nor if this is truly effective, but it gives me a good excuse to grow various mushrooms next spring.
You might be interested in the British history of Vitamin D supplementation. It all started with kids in the cities getting rickets because the pollution (smog) was that bad that they never got to see further than a metre or two during the worst of it. The way to get around was by taking the tram as that had rails to guide it through the 'pea soupers'.
So they put the kids on trains and took them off to the seaside.
But then...
The railway also allowed milk to be brought into the cities. So they added vitamin D to milk. That was how the rickets was solved. In time milk became free at school, usually it was warm by morning break, which was when it would get consumed, from mini-milk bottles, that would get reused.
I am only piecing together this history, no definitive source, unless you include my elderly neighbour. However, food history is fascinating, once you get away from celebrated brands to the unsung heroes of the vegetable aisle.
What I can't work out is why the children were so vulnerable to rickets when the adults weren't. Workers weren't being sent out to the countryside or beach to get some sun, just the kids. Rickets doesn't affect adults with grown bones, in theory, the adults should have had really painful joints and osteoporosis, but maybe this was not understood at the time.
In time the clean air zones were setup and the smog was banished to a certain extent, by which time it became uncommon to fortify milk with vitamin D. Finally we had Margaret Thatcher, famously the 'milk snatcher', for stopping free school milk.
In the UK we do get vitamin D randomly added to processed foods (what else?) and this is a scattergun approach to fortifying the population. If you don't eat processed foods then you are not going to get any of that processed food fortification goodness.
Then there are the animal corpse sources, as in oily fish and whatnot. If you eat any diet except for whole-food-plant-based vegan, then you are going to get vitamin D either through dead animal or fortification. Vegetarians just have to eat maaassivve blocks of cheese, which they will, with a few eggs and some breakfast cereal to get their vitamin D needs roughly covered. Junk-food vegans should get some vitamin D goodness from fortifications too, particularly if they consume things like 'oat milk' (as if oats have mammary glands). Pure junk food, a.k.a. 'Standard American Diet', should also be pretty good for vitamin D.
So this only really leaves the whole-food, plant-based, everything-cooked-from-scratch vegan diet as lacking, at least as far as the winter months is concerned. Was this a problem historically? I don't think so. Since people used to work the fields, they had plenty of vitamin D to carry over for winter.
Before we had 'modern day racism' in the UK, we had a situation where the aristocracy had white skin and everyone else had leathery brown skin, from working outside. White skin was proof that you didn't have to work the fields and therefore, you were higher status. Racism pre-dated racism, if you get my drift, it was mere class-based xenophobia back then. To be 'truly white' you had to have no tan.
Since meat was hard to come by, peasants were 95% vegan by default, yet working the fields, so vitamin D deficiency was not a problem, for the 1% aristocracy (since they had their oily fish, red meat and dairy) or for the 99% that had to spend lots of time outdoors.
I am not sure where you are coming from regarding the Gulf Stream and cereals. The Fertile Crescent was where farming began for Europe, with wheat not actually growing in the UK and other grains (barley) being the chosen grain. It was only with the Norman Conquest that wheat made it to the UK.
When the Romans made it to the UK they were perplexed at what they found. There were two tribes, the nomadic cattle types and the hill fort living grain growers that were not nomadic. The hill forts got in the way of the migration routes between pastures. The Romans were disgusted by the milk drinking since nobody would do that in Rome, where everyone was lactose intolerant, unlike the Celts.
> What I can't work out is why the children were so vulnerable to rickets when the adults weren't
Presumably, children need regular and consistent amounts due to bone growth. Once past puberty, less mineralization of calcium and phosphate happens, which is one of the processes in the body that requires vitamin D.
There is probably stuff we don’t know. For example, some people sneeze when they look or are exposed to the sun (for me, usually in the morning). There is still no scientific explanation for why it happens.
There are no devices that can produce a full-spectrum light like the one you get from the sun. So my suggestion would be to go outside and breathe instead of sitting in a box.
Today is the first time in December my town gets any sunlight and boy am I excited. Not because we are that far north, it's still the height of the winter after all, it was just shit weather.
I find these arguments unconvincing. But I do think that as an immortal it would be very difficult and painful to adapt to the changes in society and its values over time as an immortal. Eventually you must either join some isolated group like the Amish or else betray everything you love and believe in, over and over and over again, because whatever you think is important, the future will despise and forget it, while inventing new values incomprehensible to you now. Probably I am too opinionated to happily live even a normal human lifetime, but it's hard to imagine anyone so easygoing that a few thousand years of changes wouldn't leave them homeless.
If I were designing it today rather than in... 2008?, I would use the terms 'async' and 'await' because they are a lingua franca now. And for a modern audience that already knows what promises are it probably makes sense to start the explanation with that part. But the thing as a whole was intended to build lightweight asynchronously communicating sequential processes with private state that can be run locally or in a distributed way transparently, restarted on failure, etc. I don't think the choice of terms was obviously a crime at the time.
If you are building an application, you can and should know what your absolute time/power/cost budget is and evaluate the "speed" of operations against this absolute standard. It does not matter that some operation is 100x slower than it could be if it is still 10,000x faster than you need it to be.
But a lot of software engineering goes into building tools, libraries, frameworks, and systems, and even "application" code may be put to uses very distant from the originally envisioned one. And in these contexts, performance relative to the "speed of light" - the highest possible performance for a single operation - can be a very useful concept. Something "slow" that is 100x off the speed of light may be more than fast enough in some circumstances but a huge problem in others. Something "very fast" that is 1.01x the speed of light is very unlikely to be a big problem in any application. And this is true whether the speed of light for the operation in question is 1ns or 1min.
Apple could choose to give the users of their devices freedom to run whatever operating systems and programs they choose. Then they could truthfully say that there is no way for them to control what people do with their devices once they leave the Apple store. If you put yourself in control of such things because it is profitable, you ought to take responsibility for the consequences.
It's not really about outsmarting them. Authoritarian systems of control rely on centralization. If you create an ecosystem where end users have lots of agency, of course most of them will go the path of least resistance, but the few who are willing to put in the effort to resist still can. Google and Apple tightening their grip over their respective mobile ecosystems is a very potent lever for authoritarian governments to pull.
They don’t rely on them. They successfully use them. In the Soviet Union every one horse village with unpaved roads had a commissar. No internet, no telegraph, no newspaper, no electricity but they held control just the same. Central control makes it convenient for them, but it isn’t the difference between them existing and not existing.
In a way. Basically yes any totalitarian regime will want to create a system where the people in charge have total control over everyone and everything. But my point is that Stalin was able to exert control over all parts of the Soviet Union without the internet, Facebook, WhatsApp, backdoored E2E messaging systems, email and email spying, parallel construction, etc.
The comment I was replying to is not wrong exactly but the better way to phrase that is that any unrelated but centralized system can and probably will be co-opted by a totalitarian regime and in the long run only helps the oppressor and not the oppressed.
Surely there’s a difference between hardware being a locked down appliance and… well, a more generic computation device.
I think the argument is that Apple or even any company that makes Android phones could choose to have an open bootloader (and maybe some driver stuff) and normally that wouldn’t really offend any government, while also giving the users more freedoms.
Otherwise, what’s next, PCs that only run Windows and only allow Edge as the browser and force the telemetry on?
Chinese people lives are getting better and they largely are on the same page. Meanwhile the US has DEI in the govt while the govt says DEI is bad. Minority authoritarian rule in the US with the Senate.
The US is a brutal dictatorship all the time.
China thankfully has a govt that is on the same page as the people.
Country with social credit, LLMs that have a seizure at "Tiananment square", Winnie the Pooh and Taiwan, Great firewall, cultural genocide of Uyghurs is a country where "lives are getting better" while US is a brutal dictatorship, my fucking sides.
Is that so? I have not surveyed the Chinese, but will not be surprised if the approval was higher than you'd imagine. If anything, the core ideas of communism have clear demand in the west and people are voting for them when they are shown with a lipstick on top.
> I have not surveyed the Chinese but will not be surprised if the approval was higher than you'd imagine. If anything, the core ideas have clear demand in the west and people are voting for them when they are shown with a lipstick on top.
Ask other dictatorships while you're at it. Systems so great one wonders why stupid democracies haven't adopted the model still.
You're weasling your way out of the core point. I'm in no way advocating for such ideas. Quite the opposite. I'm just saying unless you have data about this you shouldn't rely on your instincts. There are many nuances around this and economic prosperity can mask huge other issues.
> Ask other dictatorships while you're at it.
In fact, I have observed immigrants from certain failed states that you refer to as "dictatorships." In many cases they say they hate their government yet they vote for mostly the same policies when they are given the chance to do so in the West, so again, even surveying them directly with a lazy question "do you like the government in country X" won't get you to the spirit of the answer.
To wit, you also just fell for the common fallacy of assuming dictatorship is the opposite of democracy. They are much more alike than you'd think. Democracy isn't liberty.
Would they? Unlikely, given iPhone creates a lot of jobs there. But if iPhone becomes the de facto devices for Chinese citizens to access illegal content then the chance is none-zero.
(And of course they can make Linux illegal too. It's just harder to enforce than making iPhone illegal.)
Can you give me the source of where brazil made linux illegal? I am sorry but I tried to search and the only references I could find were of brazil banning twitter/X for some reason.
I am genuinely curious how someone can decide linux to be illegal. How would the ban even work out?
Brazil has what is known as the Felca law, which requires providers of app stores and "terminal operating systems" to do age verification and to provide secure auditable APIs that meet government standards for doing the same. Presumably, specific distros like Red Hat can go through a government approval process in order to be legal to distribute in Brazil, but without such certification and without providing such system-level APIs, a random distro like Debian will be illegal to distribute in Brazil.
It's delusional to think the default OS would be replaced by anyone more than a few percent of niche users.
It's your desire to have open OS just say so. Doesn't really tie into avoiding oppression by communism. The Chinese need to solve that problem at its root.
People on HN thinking Apple should get into some kind of dick waving contest with an authoritarian government that rules over 1/6th of the global population and that supplies the labor to build their products and the materials in those products by implementing your guy’s pet issues is the height of fucking delusion.
At least try to pretend like you guys are thinking about situations in the real world.
