What's a piece of esoteric knowledge you have?

There is (or at least used to be) a debug command to write-protect a hard drive. No idea what it's for or why such a thing exists, but you flip a certain bit from 0 to 1 and drive no write. I won $100 once at work with this knowledge. We had a training course about how much better the new version of windows at the time was and how much harder it was to break - so hard they'd pay $100 (in early 2000s money) to anyone who could unrecoverably break their demo windows install during the 10 minute presentation. The instructor (who worked for Microsoft) said he'd been doing this for 6 months and they'd never had to pay out that prize before, much less 30 seconds in.

Sounds like something registry editor related.
- No, this was via debug, a command that's been included in MS-DOS since like version 2.0 (before there even was a Windows, much less full-OS windows like Win95/NT/etc rather than 3.0/3.1 that were just fancy launchers that sat on top of DOS.) It can let you view and alter the contents of memory at a particular address, etc. We also used it to wipe hard drives by forcibly writing 0s to every block on the drive.

Reign of Kings, a medieval online PvE survival game had a bug where the 360 rotation camera could be used in 3rd person mode to look inside of walls of other players. You could even access their chests if they built them against the wall (which they all did).

This meant that you could loot everyone’s bases without even breaking in. The game went through several major updates with this bug still in place. My brother and I used it extensively.

One day there is a major update and the release notes mention about how they have now finally fixed the “glitch where players items disappear from chests when placed near walls”.

Real G’s move in silence like lasagna.

I remember some roblox games I used to play let you zoom out, look into a secret room and take loot as well.

“Bizarre” is the only word from the Basque language that is regularly used in the English language

(Can’t wait to be proven wrong in 5.. 4.. 3..)

I found this really interesting so I looked it up! This website claims that "anchovy" also came to English from Basque, along with "bilbo" and possibly "jingo".

Human blood is a valid substitute for eggs in baking.

So is semen iirc.
- There's no way. It doesn't taste like eggs at all. Does it? I've never tasted raw egg before
- Nice
Human (and animal) blood and eggs can also both be used in place of Styrofoam to gelify fuel for molotovs.
- TIL. So many options to make a molotov nastier. Stinky rotten egg fires!
- What about soap flakes?
I learned this from the reverse, as eggs are a valid substitute for human blood in sacrifices.
Is it, though? I get that they have a similar protein composition or whatever, but there's no way the taste is anywhere near the same. Then again, I guess I've never eaten fully raw eggs before (not sure if a semi-runny sunny side up on toast counts, heh).
- But you have eaten raw human blood‽
Coagulation station
Calm down Dahmer
Huh, so that's why filloas de sangre are a thing. I always found it weird but it makes sense now. TIL.

ifupdown2 has a 15-character interface name limit, and the systemd predictable interface naming system uses the mac address for usb nics (giving them a 15-character name), so if you try to create a vlan subinterface of a usb nic using the standard interface.vlan naming scheme on a systemd host, it will fail, and you'll have to set up systemd network link files to rename the base interfaces to something shorter.

I'm almost sure the backstory to how you gained this knowledge is "i spent hours debugging something, and that 15 chars limit was the problem"
- Yep exactly! Setting up a raspberry pi low-performance computing cluster with secondary usb nics, going slowly insane trying to figure out why the vlan interfaces wouldn't work when their base interfaces worked just fine, and going down all of the wrong rabbit holes along the way.
It's the same when creating network interfaces via the ip tool.

Not sure if I can call this knowledge since I don't know if it's true, but I think I identified a couple of women from the 8th century CE who are mentioned in some Irish annals as actually being the same person. As far as I know there's next to no discussion of these women on the internet and there are basically no historical records of them, at least. So I guess if I'm right it's very obscure?

The women in question are Eithne ingen Bresail Bregh and Eithne ingen Cinadhon (and possibly also the legendary Eithne mother of Tuathal Techtmar)

This is a really good one. Were they/was she a notable individual? I'm imagining humorously it's a completely random person.
- It's about as close to a random person as you can get while still being recorded. They were royalty, but the two real ones get literally a sentence each at max
  Eithne ingen Bresail Bregh married the king of Tara and is described as "having deserved reward from God for her good works, and for her intense penance for her sins" in one source and "deserved to obtain the heavenly kingdom, having done penance" in the other
  Eithne ingen Cinadhon was the daughter of a Pictish king and is literally only recorded as having died
  The legendary Eithne is the daughter of a king of Scotland (mostly Pictish at the time) and crossed the sea to Ireland, where she gave birth to the hero Túathal Techtmar. This is the entirety of her role in the story; a couple of paragraphs in a collection that, in the translation I'm looking at, has 600 pages just for part five

Wait so t-tex and steggy never hung out? :'(
Also phylogenetically and morphologically.
T-Rex is more closely related to sparrows than to stegosaurus.

There are two types of color E-ink displays:

One that uses a color filter on top of a regular black and white particle display, like in their Kaleido screens. This has a faster refresh rate like black and white displays, but the colors are muted and the screen’s “pure white” is much more gray than other displays.

One that uses four colored particles, cyan, magenta, yellow, and reflective white, like in their Gallery screens. This has a much slower refresh rate, but the colors are vivid and the screen’s “pure white” is just as good as a non-color screen.

There are also color transflective LCD screens from other companies that are sometimes marketed as “e-paper” or “paper like” that are fairly uninteresting.

And there are just straight up backlit LCD screens marketed as “e-paper” or “paper like” that are just not. XPPen just made one. I personally think this should be considered false advertising.

The SR-71 used an Astroinertial Navigation System that used stars to keep the navigation information accurate as the plane flew over long distances. Normally an inertial navigation system degrades in accuracy over time and distance due to small errors building up and something called gyro drift. The NAS-14V2 used a catalog of known stars and a gimballed telescope to identify specific stars (even during a cloudy day) and determine the position of the stars in relation to the aircraft. Using this information the position of the aircraft can be used to revise the inertial navigation system's data every so often so the accuracy is much better.

And this was required because the SR-71 started flying in 1966, and the first GPS satellite didn't launch until 1978. The full GPS constellation wasn't finished until 1990.

Hm, I guess this is esoteric in the sense that most people aren’t interested in it?

Some clothes are made with what’s called ‘slub cotton’, which is cloth made from cotton thread that has irregular lumps jutting out of it. It gives the final woven fabric an interesting look, almost like static. If it’s done with bright or contrasting colors it can give a really interesting pop to the final item.

Hermeticism is the origin of most conspiracy theories if you dig deep enough. Truly the OG brainworm

That's, like, meta-esoteric knowledge.
at least it's airtight

The great opera singer Enrico Caruso was the 18th of 21 children, only 3 of whom survived infancy.

Johann Sebastian Bach wrote an opera about coffee addiction.

The Russian composer Tchaikovsky was afraid his head would come off while conducting, so he would hold his chin with one hand while doing so.

The girlfriend of composer Erik Satie wore a corsage made of carrots, and she was a painter and liked to feed the paintings she made. Satie once threw her out the window but she survived.

Fucking hell, even Satie ??
- Even Satie. Who collected umbrellas.

We don't know if π+e is irrational.

We don't know if π*e is irrational.

Briefly looked into it, and found an old stack post that said we know at least one is irrational. It would be pretty interesting if the other were rational.

The most efficient base for a number system is e.

We use base 10 with 0-9 digits and each position is a ten's place, and the efficiency being measured is the product of the number of digits and the length of digits needed to represent a number in a given range of values. So if we used base 2 binary instead of base 10 decimal we only need to remember 2 digits 0-1, but to represent most numbers we'll need more digits, 11 in base 10 is 1011 in base 2. On the other side we could use hexadecimal to write shorter numbers like 11 is B, but need to use more digits, 0-F digits where A-F are the 10-15 digits.

If you try to plot a function that minimizes the efficiency the minimum is at e. So you'd have digits 0-2 and e would be written as 10 since each position is an e's place.

This is not a great explanation of radix economy of Base e.

Wsl uses the 9p protocol from plan 9 to interact with windows and vice versa

That is really interesting actually. wsl1 or 2?
- I believe both
I use 9p for some qemu VMs and had no idea it was a protocol from plan 9.

All contradiction is reconciled above the abyss, hence why spiritual visions can sometimes appear horrible at face value.

Wait, what kind of esoteric did you mean?

My ICQ number...

Uhoh

There is only one model structure that can be put on the category of small categories for which the weak equivalences coincide with honest equivalences of categories. It's called the Joyal-Tierney model structure. You can define the suspension of an object in any model category as the homotopy pushout to two terminals, then define an abstract notion of a sphere in any model category by setting the 0-sphere as the coproduct of two terminals and the (n+1)-sphere as the suspension of the n-sphere.

A small category is a CW-complex if and only if it is a groupoid.

I have absolutely no idea what you said. But I have a really awesome friend named Tierney.

The UK issued silver dollars once. They were dated 1804 and considered "bank tokens" as they had less silver than their denomination required at the time. They basically stamped a new design on Spanish colonial 8-real coins and passed them as five shillings.

The UK had a hard time with coin supply for most of the 1700s until 1816 when they finally downdized many coins.

All of it

love this concept. ever found anything interesting?

I'm Western esotericism, names have power beyond simply being signifiers for the thing they represent- they embody some part of the thing they represent. The word "fire" contains some intrinsic "fire-ness" but not the whole picture. After all, everyone has different names for the same thing. It is thought that everything has a "true name" that perfectly encapsulates all things about it in their entirety, and this true name could be found by intense study, meditation, or etymology. The Bible pays a lot of attention to names in this way. Adam, the first man, names all the animals. Genesis pays a lot of attention to the names of places, and a lot of stories in Genesis are essentially folk etymologies of locations. God's own name is of special importance, and its meaning was revealed to Moses by the Burning Bush. Even today Jews believe that even saying God's name is powerful and dangerous and that only the High Priest would be allowed to say it once every year during Yom Kippur. Jewish folklore says that even this name is merely a part of God's true name, and that Moses pronounced a longer more complete form of The Name to part the Red Sea, and some systems hold that there are even longer and even more complete forms that have been known to rabbis in the past.

Oh, so that's where Christopher Paolini got the idea of true names for Eragon!
- Yeah it's a very old concept and used in fantasy even before Eragon.
That god actually has a name?
- Yes. God's name is super interesting because of the extremely strong taboos surrounding saying it, stemming ultimately from the Third of the Ten Commandments (Exodus 20:7)- "Thou shalt not take the name of the LORD they God in vain; for the LORD will not hold him guitless that taketh his name in vain." Note the emphasis on the name of The LORD, and how the word "LORD" is all caps- this is a sort of censorship of God's actual name, which goes back to the ancient Greek translations of the Hebrew scriptures. When you see "LORD" in a Bible passage in English, the original passage has God's name in Hebrew. Jews have historically said the word "Adonai" (meaning Lord) instead of God's name when reading aloud, and almost all translations follow this and just use the word for "Lord" (Kyrios, Dominus, etc.) instead.
  Anyway, the name is rendered in Hebrew as "" which is roughly equivalent to the letters "YHWH" in the Latin alphabet. Hebrew doesn't use vowels, and the vowel sounds hsve intentionally not been recorded by scribes. The modern academic reconstruction is "Yahweh" for the pronunciation based on names for people and places that include parts of the name. You may also see "Jehovah" in some contexts which is based on older German scholarship that incorrectly rendered the vowels of the word. The name's meaning is given to Moses in Exodus 3:14 where Moses asks who he should tell his people to worship and God replies "I AM WHO I AM" "Say this to the people of Israel: I AM has sent me to you" (in Hebrew, I am who I am is Eyeh Asher Eyeh). Modern scholarship agrees that the name has some connection with the word "to be" and means something along the lines of "The Existing One."
  Myself, I interpret God's response in the story and the meaning of His name as a declaration of self sufficiency, that God is what exists in His own right, and doesn't need anything or anyone else to exists. It's not only a declaration of montheism, but a declaration of supremacy over all of the universe. But yeah, not only does your Bologna have a first name, but God does too if you're Christian or Jewish.

I mean I've spent time studying occult stuff, so I guess pretty much the trope codifier.

Turns out they mostly just like to do the macarena. ¯(ツ)_/¯

If you stare at the elbow of someone you are high-fiving, you'll never miss the high five.

I don't think that's esoteric. It's just ergonomics at plat

There's a trick with our loan servicing XML imports. If you pre-encode the property address into a [Comment] tag inside the [CIF] section, the system auto-fills it in three different screens, even though none of them actually pull from that tag offcially. I don't know why it works, just that it does. Doesn't really save me more than about thirty seconds but when you're boarding dozens of loans per week, it can add up.

https://en.wikipedia.org/w/index.php?title=Wikipedia%3AArticles_for_deletion%2FJeff_V._Merkey&oldid=324345203

Wow. From everything I could find that he wasn't able to nuke, he sounds like a trip!

From an old edition of the Pilot's Handbook of Aeronautical Knowledge:

An airplane's tire will hydroplane at a speed in knots equal to 9 times the square root of the tire pressure in PSI. So if your tires are inflated to 36 PSI, sq.rt 36 = 6 * 9 = 54 knots. If there is standing water on the runway, you will have no braking authority or steering control from the wheels, you will have to maintain control of the aircraft with the flight controls, and you cannot rely on short field stopping figures from the POH if it requires applying brakes above 54 knots.

I got that out of the 2003 edition; I don't know if it's in the current issue.

Everything you learn from being active on Tumblr from late 2012 to now

Mammals generally get 1.5 billion heart beats in their lifetime regardless of size.

See, mega corps are simply mimicking nature by implementing planned obsolescence
So is cardio shortening your life?
- I don't think so, these numbers are population averages and the relationship probably doesn't apply at the individual level. Also humans don't tend to follow this rule as closely due to things like medicine.
And they all (above 3Kg) pee on average for 21 seconds.