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Ask HN: Teach me something new

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Re: Ask HN: Teach me something new

#371

If you use git and clone the same (or related) repositories in multiple places on a single disk, they can share the hashed object to reduce disk space and/or network usage and increase speed. One workflow is to git clone mirror the main repo and use that as a shared read-only source of historical references when cloning a new repo. You can also hardlink or reference those objects to save disk space (though some file…

Sounds like the worktree feature in git: https://git-scm.com/docs/git-worktree

Re: Ask HN: Teach me something new

#372
post #229

In statistics, the mean and median are both averages, but are technically quite different. The mean is the sum of all items divided by the number of them, while the median is the middle item in the sorted list. When they are different, this can have strange effects. For example, when estimating engineering tasks, the mean error is often positive while the median is often negative. This is why your manager believes th…

If the project is planned according to median, you accept up front that there is 50% chance the project will be late.

It's worse than that. You need the median time for the whole project, which you can't get just from summing the medians of the individual tasks.

Re: Ask HN: Teach me something new

#373
post #260

You probably heard about the quirks in the French numerical system. For example, 99 is translated "quatre-vingt-dix-neuf" which is literally "four twenty ten nine". This is a legacy of the base 20 numerical system used by the Celtics thousands of years ago before the modern Romance language drove it out. The hybridization with our current base 10 system came with the Roman conquest of the Gaul. Another example of the…

A lot of French people are very materialistic. They're obsessed with Monet.

I thank you. I'm here all week...

Re: Ask HN: Teach me something new

#374
In the western/european world, we have access to maybe a couple of dozen types of fruit (including various berries); try listing all of the fruit you know. That is just a small fraction of the (estimated) 2000 types of fruit eaten across the world, particularly in the tropics.

Relatedly, in central and south America, _sapote_ is the native american term for (roughly) "edible fruit". The word has nothing to do with the taxonomy of these plants. European colonists made the mistake of adopting the word "sapote" for various different tree species ("what's this called?"; "sapote"), which has led to a lot of subsequent misunderstanding. If you google for "sapote" you'll find some results which naively attempt to give a latin classification to the unqualified "sapote". Now we have fairly useless english names for a variety of these regional fruits, such as (read "sapote" as "edible fruit" in these examples): "green sapote", "white sapote", "black sapote", "yellow sapote", "sun sapote", "south american sapote", and so on - although many of them also have more distinctive names (such as "canistel" or "chupa chupa"), which are much less ambiguous and should be preferred.

The company United Fruit was formed by the merger of two companies in 1899. One half of the merger was originally founded by an american railwayman, who obtained a 99 year lease of 800,000 acres of land from the Costa Rican government in exchange for constructing and operating a railway from the capital city to the carribean port of Limon (during the construction of which, thousands of laborers died from tropical disease). Once the railway started operating, usage was insufficient to pay back the debt on the loans that he'd taken out for construction, and so he pivoted to banana exports; the story goes that he had planted bananas along the tracks during construction as a cheap means of feeding his workers (which doesn't quite make sense given that bananas take 14+ months to fruit), and so he doubled down by increasing the density of planting over the area of the land that he owned, of course clearing more primary tropical forest to do so. The United Fruit company (today Chiquita) became heavily involved in politics in the countries that it was operating in, with the most famous example being its significant role in instigating the CIA backed coup in Guatamala in the 1950s that overturned the democratic government and installed a violent dictatorship, and led to 4 decades of civil war in which at least 140k people died, and which set Guatemalan economic development back by decades or more. So yeah, bananas.

Oh, and finally, there are dozens of varieties of bananas. The one that's exported most commonly (Cavendish) is relatively large and travels well, but is far from the most flavorful. There have been rumors of a killer fungus for many years, which hasn't had a significant impact on availability (yet); however, there are many varieties of bananas that aren't impacted by this fungus, so in the next decade or two we could see one of the other varieties replace Cavendish as the most widely consumed.

Re: Ask HN: Teach me something new

#375
post #2

Quantitative easing (sometimes mistaking called "money printing") isn't directly inflationary. Because when central banks buy bonds, they do not pay with normal money. Instead, they pay with a special type of money that can never enter the real economy (as to not create inflation). This special type of money are called "bank reserves". And bank reserves can only be used to 1) settle interbank transfers and 2) buy mor…

So the person who sold those bonds after buying them from the government gets that money - in effect the government gets that money. In a puritan world sure, but if you expect the Fed will buy the bonds you can just buy them from the government and then sell to the Fed. And because there were negative interest rates for a time, that is exactly what happened as any other reason would be irrational.

So it's not a closed loop - it's just printing with more steps.

Likewise now its destruction with the removal of these reserves.

Re: Ask HN: Teach me something new

#376
post #260

You probably heard about the quirks in the French numerical system. For example, 99 is translated "quatre-vingt-dix-neuf" which is literally "four twenty ten nine". This is a legacy of the base 20 numerical system used by the Celtics thousands of years ago before the modern Romance language drove it out. The hybridization with our current base 10 system came with the Roman conquest of the Gaul. Another example of the…

Famous english language example: https://en.m.wiktionary.org/wiki/four_score_and_seven_years_...

Originally from literal score in wood made as a tally mark when 20 items were counted.

Plus, dozens (and gross).

And base 60 becoming standard for time and degrees of a circle.

Minute (unit of time) comes from "minute (smaller part)", and second from second minute (small part of the small part).

Re: Ask HN: Teach me something new

#377
post #260

You probably heard about the quirks in the French numerical system. For example, 99 is translated "quatre-vingt-dix-neuf" which is literally "four twenty ten nine". This is a legacy of the base 20 numerical system used by the Celtics thousands of years ago before the modern Romance language drove it out. The hybridization with our current base 10 system came with the Roman conquest of the Gaul. Another example of the…

Surely they the French could figure out that "neuf-dix-neuf" could work as well. I'm learning some South East Asian languages and the simplicity is astounding. Who needs "dix" when "dua dua" works just as well? (Indonesia)

Some French speaking countries use a more logic term for higher numbers. In Belgium and Switzerland 99 would be nonante-neuf which is ninety-nine.

My uneducated guess is that at the time, it was easier to keep the base 20 to visualize a higher number. Just like we say "a few dozen eggs" to get an overall sense of the volume, it made more sense to keep it that way instead of a more arithmetic approach. Not sure why it never evolved, tho.

Re: Ask HN: Teach me something new

#378
post #196
post #140

Earlier quoted context omitted.

If I’m a Boltzmann brain that can only survive for an instant, why do I experience existing for a whole lifetime?

You haven't experienced a whole lifetime. Every moment up until the current [whatever the smallest unit of time really physically possible is] is just a memory of an experience. Subjectively from your perspective there's absolutely no difference between having actually experienced all that and merely having memories of having experienced all of it. You could materialize into existence for exactly one moment and belie…

Now that's an existential crisis right there. There's no way to determine if I've literally flashed into existence and am remembering this sentence, and am thinking of how to continue it, versus actually existing on the timescale of a human life.

Urgh.

Then again, does it matter? Probably not.

Re: Ask HN: Teach me something new

#379
post #371

If you use git and clone the same (or related) repositories in multiple places on a single disk, they can share the hashed object to reduce disk space and/or network usage and increase speed. One workflow is to git clone mirror the main repo and use that as a shared read-only source of historical references when cloning a new repo. You can also hardlink or reference those objects to save disk space (though some file…

Sounds like the worktree feature in git: https://git-scm.com/docs/git-worktree

Kind of distinct but could solve similar problems where they overlap.

Worktrees let you have different branches from the same repo checked out to the file system at the same time, without needing seperate repos.

The clone --shared --reference-if-able and -dissociate options let you have multiple repos with less of a space hit.

They almost certainly can be used at the same time, though I've never heard of anyone doing so.

The limit of only having at most a single copy of each branch checked out, which makes sense for development purposes, made worktrees unsuitable for my use, which was mostly (ab)using git as a deployment tool.

Re: Ask HN: Teach me something new

#380

I've described this on HN before; forgive me if you've already seen it. I have chronic migraine. It sounds worse than it is; I rarely suffer attacks anymore, and when I do, they're usually mostly harmless, as in the case I'll describe below. Contrary to popular belief, migraine is not a headache. It's something a little more like an epileptic seizure. Intense headaches are one common symptom, but there are a lot of o…

Thats cool as hell thanks for sharing!
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