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gxxbgu
|
How does restricting password length or repeating characters make a password more secure? If it doesn't, why do some companies enforce it?
|
Technology
|
explainlikeimfive
|
{
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"Minimum length makes minimum complexity more likely. Maximum length is harder to justify nowadays. Passwords are cracked by brute force, using most likely sequences first to spend less time and then going to less frequent and eventually random. No resorting characters makes complexity a bit higher but if the result is in a cracked database it doesn’t matter. Companies enforce it by history and sometimes laziness. My ex company forced us to change passwords every 3 months. Meaning everyone had a sort of increment in their password making the measure moot.",
"May I direct you to the XKCD comic that explains it quite well: URL_0",
"Password requirements don't make passwords safer, they just exclude really bad passwords. Many, if not most, users would use relatively weak passwords, so for them it's an improvement. Passwords of exact length are just stupid.",
"They want to prevent people from using \"a\" as their password, so they implement a minimum length. They want to prevent people from using \"aaaaaaaaaaaaaaa\" as their password, so they implement a restriction on repeating characters. For maximum password lengths, no idea. Either they are stupidly storing passwords in plain text (and the database field has a certain max length), or maybe they just want to prevent people from using an absurdly long password like copying an entire novel into the password field.",
"When you type in a password, a special algorithm called a \"hashing function\" irreversibly converts the password to a unique \"hash\". The hash is then stored. When you come back and type your password again, it's converted to a hash also and the hashes are compared. If they match, the correct password was entered. Sometimes the hash files are leaked. When this happens, people can test the hashes against billions of possible passwords and often they'll find a match. The theory behind the password restrictions is that your password is less likely to be discovered in reasonable time. It makes sense that \"iloveyou\" will be tried long before \"I*Love7*You\". Unfortunately these restrictions make passwords harder to remember and often don't add much security. Guaranteed the above example will actually be \"Iloveyou1\". But for now we're stuck with these rules."
],
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"text_urls": [
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"https://imgs.xkcd.com/comics/password_strength.png"
],
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[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gxy8b4
|
Can the goverment block Internet to this level, that nobody could get over it, or its imposibble?
|
Technology
|
explainlikeimfive
|
{
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"ft6lcrp",
"ft6ipdr"
],
"text": [
"Sure. Many countries have internet/communication infrastructure that is completely controlled by the government, so disabling it is fairly simple. Some people may still be able to get wireless or cellular access from neighboring countries, but the majority won't. In countries like the US where the communication infrastructure is privately owned by many dozens (or more) of different companies, and there are lots of redundant connections this would be much more difficult.",
"Governments do this all the time. As you might expect, this makes people mad."
],
"score": [
11,
5
],
"text_urls": [
[],
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}
|
[
"url"
] |
[
"url"
] |
|
gxyby3
|
How my phone battery goes from 0-50 in 30min but 50-100 in 1 hour?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft6kd89"
],
"text": [
"fastcharge technology. It will let higher current into the battery at the begining so you can use your phone faster, but because this can be damaging to the battery(higher current will heat up the battery) it slows down in the charging once it reaches 50%."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gxzsc0
|
How all professional music sounds the same quality?
|
If I record myself singing it'll sound like shit, even if I have a relatively good microphone. I know the pros sound good because they have sound isolated rooms and good quality mics, but listen to any song on the radio and the voices all sound like they're using the exact same mic in the exact same studio. How do they all sound the same? I can't imagine every studio has the exact same setup so how do they all get the same level of quality? Or can I just not hear the difference?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft75qyc"
],
"text": [
"Don’t forget, there’s a ton of in-studio processing that goes on when all the different song elements are being mixed together. Vocals will typically undergo processes like ‘compression’ and ‘multi-tracking’ along with various FX like ‘delay’ and ‘reverb’ - just to name a few. There will be various different takes, some at different vocal registers, to harmonise and ‘thicken’ the vocal - all multi-tracked and blended together with the other instruments to give you the end result. So, an awful lot of stuff done to a studio vocal to polish it. Even live, a lot of stuff can be added and done to drastically improve a vocal performance (Autotune, anyone?). Plus, radio output is often heavily compressed, which probably makes a lot of music sound rather homogeneous."
],
"score": [
4
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
gy2wgw
|
Why does old file formats were so prone to getting corrupted (3gp, mpeg, wmv) seemingly out of nowhere but new file formats are more reliable?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft82xpe",
"ft8wqr5"
],
"text": [
"The formats you are talking about are specific for the delivery of streams and have the design which does do allow recovery of corruption of the stream and resuming the decoding of the stream midway: The format has header frames with signatures which allows the decode to determine where a header could start have started. So if the problem is not with the data format, then the problem lies with the decoder and its ability to recover from corruption: That is the part where there has been a lot of improvement.",
"They're not. Corruption is an unintended change in the data. That can occur due to bad software writing the data, or due to hardware failures so that it's corrupt when you read it. That has nothing whatsoever to do with the formats used. It can be either a hardware failure of the storage medium or a software failure of whatever wrote the data. But it's all just 1's and 0's. Either whatever wrote it failed to write it correctly, or whatever stored it failed. So the 1's and 0's being read later don't make any sense. Since you are comparing old to new, it's reasonable to assume that you're pulling data from an older system, and seeing that some of it is corrupt, and comparing that to new data on a new system. That most likely indicates that the old hardware failed to store the data. That's a hardware failure, not related to the storage format."
],
"score": [
8,
3
],
"text_urls": [
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[]
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|
[
"url"
] |
[
"url"
] |
|
gy3og6
|
How did the atomic bomb Fat Man work?
|
I am on google yet still don’t get it. Edit: Thankyou all for the responses
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft8cfyp"
],
"text": [
"All radioactive materials emit some kind of particle as they decay. Some materials (which may or may not be radioactive) can absorb those particles and become unstable (or more unstable) and decay, which will emit some kind of particle. In the case of plutonium, it will emit neutrons, and also it will absorb neutrons to become unstable and decay, causing it to emit neutrons which surrounding plutonium atoms will absorb. However, the rate at which plutonium decays naturally is too slow to cause that kind of chain reaction. Not enough neutrons are emitted fast enough to sustain the reaction. Not all neutrons are absorbed, especially fast-moving neutrons emitted by plutonium decaying. To get the bomb-causing chain reaction, you need two things: a big, \"supercritical\" chunk of plutonium that is very dense so it's harder for neutrons to \"miss\", and something to pump out a *ton* of neutrons to get the reaction started. The Fat Man explosion starts with conventional chemical explosives arranged in a sphere around the rest of the bomb (well, the important part starts there, anyway). There is a mixture of different kinds that burn at different speeds, which is important to balance the reaction inside. If the chemical explosives are too powerful, the radioactive material will just be blown apart before it goes supercritical. Too weak or too slow and, again, it'll just fall apart before going supercritical. An altimeter sensor sets off a primer which sets off detonators which set off that mixture of high explosives. Surrounding those high explosives is a shell made of dense lead to contain the blast and direct the powerful shockwave inward. Inside that shell of explosives is a *tamper* - an aluminum shell that absorbs that shockwave energy and transfers it to the next shell inside like a hydraulic press powered by explosives. Underneath that is the plutonium core - the main chunk of plutonium that will provide the bulk of the nuclear part of the bomb's energy. However, the plutonium chunk is not supercritical - it's big, but there's not enough of it close enough together to cause a chain reaction. When the chemical explosives go off, the aluminum tampers crush the plutonium so hard that it becomes dense enough to be supercritical. That shockwave continues inward. The next shell is a thin shield made of boron that absorbs neutrons, preventing the *modulated neutron initiator* from prematurely leaking too many neutrons and maybe accidentally causing the whole thing to explode. The boron shield is destroyed by the shockwave when the bomb is detonated. Which brings us to that modulated neutron initiator - aka the \"urchin\", which is at the center of the bomb. It is made of beryllium and polonium and more beryllium separated in a *very* specific way by some nickel and gold. [Here is a diagram]( URL_0 ). When the shockwave reaches the core, it shoves all that stuff in the urchin together and basically instantaneously mixes them together into one single very dense blob of polonium and beryllium. Polonium has a very short half-life and decays very quickly, emiting alpha particles as it decays. It does this all the time anyway, but inside the urchin the alpha particles are absorbed by the gold/nickel and don't do anything. Once mixed, though, the beryllium absorbs the alpha particles and then very *very* rapidly decays, spitting out a *lot* of neutrons in the process, nearly all at once. Those neutrons bombard the now supercritical plutonium core, causing the plutonium to start to very *very* **very** rapidly decay, which spits out even more neutrons, which bombard the rest of the plutonium core, which causes more plutonium to decay, and so on, creating the chain reaction that leads to the *nuclear* part of the nuclear bomb. So: Altimeter sensor - > primer - > detonator - > mix of high explosives - > shockwave - > aluminum tamper crushes - > plutonium core which becomes - > supercritical plutonium core - > and also crushes the modulated neutron initiator - > polonium and beryllium mix instantly - > polonium is already decaying naturally - > alpha particles - > beryllium decays - > blast of neutrons - > hits supercritical plutonium core - > plutonium decays - > more neutrons - > plutonium decays - > more neutrons - > plutonium decays - > etc. - > ~~city~~"
],
"score": [
9
],
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[
"https://pbs.twimg.com/media/DPsNszNUMAEVGmz.jpg"
]
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|
[
"url"
] |
[
"url"
] |
gy6b6h
|
How do spam text messages get my phone number if I haven't signed up for anything or given it out?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft8oz7z",
"ft8u1ju",
"ft8p5xe"
],
"text": [
"Entities that send spam texts have to have bought your information from someone. Very many companies, like Facebook, magazines, grocery stores, online retail, etc., unless very explicitly stated otherwise, are selling your information. All it takes is for one company to sell your number one time and it’s in databases forever.",
"It's guaranteed your phone number is between 000-0000 and 999-9999 in your area code. Sending one text is free. Sending thousands of texts is almost free. If scammer gets 1 hit out of a million, that's already profit since costs are basically nothing",
"(Assumption) all cell phone numbers begin with area codes, so they just use the area code of somewhere they want to target, then send it to a random number, and if you reply then they know that the number they typed in is one used by a real person, and to continue sending messages and/or calls to that number."
],
"score": [
24,
11,
5
],
"text_urls": [
[],
[],
[]
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|
[
"url"
] |
[
"url"
] |
|
gy6vlm
|
How did people cut their toenails before clippers/scissors were invented?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft8swdy",
"ft8x6xg"
],
"text": [
"You can use a small sharp blade like a paring knife. They even had curved blades that were only about 1” long for this exact purpose.",
"You just need an edge and a bit of practice. I'll often \"cut\" mine by using my fingernail then polish them up with the file. Granted, this only works with decently strong, grown out fingernails. I just really hate the *snap* from using clippers on my toenails."
],
"score": [
25,
10
],
"text_urls": [
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
gyb2ed
|
Why can't desktop monitor settings like brightness and contrast be controlled via desktop software?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft9fcqi"
],
"text": [
"I don't think an intrinsic technical limitation exists, I use software (OnScreen Control) to control brightness, contrast and others things. Maybe the implementation in all the monitors is not worth-it?"
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gyb9sv
|
what is the purpose for having designated left and right earphone?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ft9g5it",
"ft9p2d0",
"ft9gi26"
],
"text": [
"Some songs/shows have referenced sound, for example the characters moves from left to right, the sound \"follows\" him.",
"For left and right sound? You can have directional sound. The audio jacks are designed that, if either the port or the headphone does not support directional audio the cables are shorted together and you fall back to mono-sound, the same sound on both ears. Directional sound is important in gaming to differentiate which side the sound came from. If the big baddy comes from the right and you turn left you get eaten.",
"I can see two main reasons: having designated left and right earphones allow them to better fit in yout ears compared to undesignated ones and some audio content can differentiate what you hear in your left and right ear so as to give a sens of location where the sound might come from. For example in some video games, the left and right earphone emit different sounds at different volume or with a slight shift between the left and right earphone to better inform the player of the location from where the sound comes from."
],
"score": [
7,
3,
3
],
"text_urls": [
[],
[],
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|
[
"url"
] |
[
"url"
] |
|
gyi6k1
|
how does analog audio work? (Like vinyl records)
|
So this might be a dumb question but I've never understood how etching a Grove into some plastic can lead to the same sound as a human singing with backing instrumental? It just never made any sense to me
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftanfjq"
],
"text": [
"Sound is simply variations in sound pressure. Take a sheet of paper, and mount it in a frame, so that it's held securely. If you blow on it, it's going to flex away from the air. Now attach a needle to that and make it make a groove in something, which will follow those vibrations in the air. That's really all there is to it. All sound, no matter how complex, adds up to some amount of deflection during a point in time. If there's multiple sounds at once they just add up with each other."
],
"score": [
3
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
gyiyae
|
What happens to your data when SSD's cells wear out after being written many times ?
|
Does your Windows / favorite video game just get corrupted all of a sudden ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftar0zu"
],
"text": [
"Not unless the SSD controller screws up big time. SSDs keep track of how many times they write to which block. The manufacturer decides how many time a block is supposed to be written to before it's considered degraded. When a block reaches its maximum number of writes, the controller sorta *retires* that block and uses a healthier spare block in its place."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gyjh65
|
How is ultrasound used to view an unborn baby?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftb1s00",
"ftauob5"
],
"text": [
"Using sound waves is like bouncing a rubber ball against the pavement or against the grass. The rubber ball will bounce differently depending on what it bounces off.",
"Ultrasound is a sound wave with a very high frequency that humans cannot hear. These frequencies can travel through the soft tissues and fluids, and echo back once they get to a denser object and cannot travel any further."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
gyk5vk
|
in computers, what do “wired memory”, “compressed memory” and “Swap” mean? Why is it bad that a computer is using a lot of Swap?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftaxijc"
],
"text": [
"> ELI5: in computers, what do “wired memory” That's an OSX specific term for memory which can't be swapped out. So pretty much memory that's taken no matter what, for various technical reasons. > “compressed memory” It's kind of an intermediate kind of swap. Rather than writing out something rarely used to disk, it's compressed and kept in RAM. This is faster than writing it to disk, because disks are slow, even SSDs. > and “Swap” mean? Stuff that used to be in RAM, and was now written to disk because it wasn't needed much. This is things like those browser tabs you've opened 3 hours ago and not looked since. > Why is it bad that a computer is using a lot of Swap? Mostly because it's a sign you don't have enough RAM, and having to use the disk to compensate by moving out the rarely used bits. But disk is very slow compared to RAM, so using a large amount of swap risks everything grinding to a halt."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gymuwn
|
Why are car alarms programmed to go off for so long?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftbcd5f"
],
"text": [
"Since the car is mobile it is useful to have a loud, prolonged alarm. The volume is meant to annoy thieves and alert nearby do-gooders. The duration is meant sustain these forces. Alarms in this sense are 'overt' security features. Whereas, a lot of commercial security is purposefully silent as to give a tactical advantage to a (stationary) premises."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gyr96y
|
how does petrol engines differ from diesel engine?if so then what type of engine is used in rockets?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftc3q6k",
"ftc49yh"
],
"text": [
"In a gasoline engine, fuel and air are mixed and injected into the cylinder. The piston compresses them. Then a spark plug creates a spark which ignites the mixture. In a Diesel engine, air is injected without fuel. The air is compressed to a point where it is so hot that fuel would ignite on its own if it were present. This would mess with timing and such, so the fuel is injected at the end of this compression stage. Because the air inside is so hot, the fuel ignites. Diesel engines also have something called glowplugs. Because a Diesel engine requires the heat of compression to ignite the fuel, it can be hard to start an engine in the cold. Glowplugs are basically just heating devices to help get over the initial cold when starting. Rocket motors are reaction engines. They produce thrust essentially by chucking all the burnt stuff out the back, *really* fast. The underlying principle is basically the same though — a fuel and an oxidizer are mixed, ignited (once, unlike intermittent automobile engines, rocket motors are typically continuous), and the reaction products are expanded inside a nozzle, which produces thrust.",
"Both use a piston (I'll leave the Wankel Engine out of this) Petrol or gasoline engines work like this. The piston is pulled down to the bottom of the cylinder. During this process the cylinder is filled with a combination of air and fuel. The piston is brought back up to compress the mixture and ignite it with a spark from the spark plug. The Combustion forces the piston down and starts the process over. Diesel works similar. However the combustion is caused by the air temperature after compression. As the air fuel mixture is compressed it heats up and then ignites. Rockets use something completely different. They use Rocket Engines. Fuel and oxygen are combined and sent to a compression chamber and ignited. The exhaust is then sent through nozzle. That nozzle will help accelerate the flow. This produces the thrust needed to move the rocket."
],
"score": [
18,
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
gyxlc6
|
Why are the letters on the keyboard not arranged in alphabetical order?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftcz2wc",
"ftcyqpv",
"ftczd2c"
],
"text": [
"They were designed when typewriters were commonly in use. The keys were arranged in a way that made the typewriters get jammed less often (this was a pretty big problem). Modern keyboards just continued using the same format because typists were already used to it.",
"They are arranged so that the most frequently used letters are in the easiest to reach spots",
"The keys are arranged to minimize the number of times you need to press keys that are right next to each other (because that jams mechanical typewriters), and to ensure you use both hands as much as possible, because that makes for better typing. For whatever reason if you stick to one hand for a long time you end up making more typos. In modern times, more optimal layouts like Dvorak have been devised, but it didn't catch on."
],
"score": [
11,
5,
5
],
"text_urls": [
[],
[],
[]
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|
[
"url"
] |
[
"url"
] |
|
gyz8wz
|
Why does staring at a tv screen in the dark cause eye strain, but a cinema screen is fine ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftdg7x2",
"ftdzysa"
],
"text": [
"Any eye strain you're feeling is due to the distance the screen is from your eyes. Your eyes are most relaxed when looking at something far away, like the theater screen. When looking at something closer, like a computer monitor or your home tv screen, your eyes need to focus the light, causing your lens muscles to be under tension, and they fatigue.",
"TV's are bright enough to watch in a fully lit room. Have you ever been in a theater with something on the screen but the lights on, you can barely see what is on the screen. Eye strain from a TV in a dark room is cause by the contrast between the light of the screen and the backround. [ URL_0 ]( URL_0 ) Because a movie theater screen is so much dimer the contrast to the darkened room is less and will cause less strain."
],
"score": [
14,
4
],
"text_urls": [
[],
[
"https://www.sciencedaily.com/releases/2006/04/060425015643.htm"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gz390v
|
What is CMOS technology and how does it work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftdyt1o"
],
"text": [
"CMOS is more of a layout than a technology, we use it to make low power logic gates In something like an inverter you just need to flip the signal so if a 1 goes in a 0 comes out and vice versa. You can do this really simply with a transistor and a resistor but whenever the transistor is on you'll burn off lots of power in that resistor which isn't ideal CMOS has you replace that resistor with the **C**omplementary type of **MOS**FET thus the name CMOS. If you were previously using an n-type FET on the bottom and a resistor on top then you'd replace the resistor with a p-type FET. The end result is that when the n-type is on the p-type is off so the output is 0 and no significant current flows. Conversely if the n-type is off then the p-type is on and the output is high but again no significant current flows. Old logic gates did not use CMOS and ran hot, but most modern digital devices have their transistors laid out in a CMOS style to minimize power consumption."
],
"score": [
6
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
gz6zni
|
How come my Nintendo Switch charger charges my phone 10x faster than the actual USB-C charger that came with my phone
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftemou7"
],
"text": [
"Check the output on the block part of your chargers. You should be able to see this info in the small print usually around the prongs. You'll see something like 1-2 Amps (or equivalent milliamps). More amps = faster charge rate. Older cell charges have around 1A output which can be pretty slow by today's standard of about 2 or 2.1A. I imagine the Switch charger would have a high output than a cell phone charger."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gz7ilv
|
how does my phone screen stay on to tell me to charge my phone if my battery is dead?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ften2qp",
"ftenfob"
],
"text": [
"When your battery is dead it's not really dead, your phone shuts off before that happens because it causes problems",
"Tech these days has a reserve bit of power to make sure no program errors can occur from a forced unsafe shutdown. And auto shut down occurs before this reserve power is utilized."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gze4r3
|
How games with random structures can generate the same complex world twice using the same seed.
|
I just don't get how a game like Minecraft can generate the exact same enormous world if you use the same seed, that can be a really small text
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftfqnn1",
"ftfygz8",
"ftfuwb5",
"ftfuevk",
"ftftvg0"
],
"text": [
"The random number generator uses the seed to generate other random numbers using some steps For a particular method of generating random numbers if the seed is same, then the exact same set of numbers are generated each time.",
"As other people have pointed out, random number generators take the seed and generate a seemingly random number from them, but lets put that into a more concrete example. Lets say we have a function \"(X*123)\" X is the 'seed' in this example. Plug in 1 for X and we always get 123 Plug in 2 for X and we always get 246 Plug in 3 for X and we always get 370 This isn't doesn't look all that random. We can quite clearly see the progression to bigger numbers for each bigger value of X. What if instead we just want a 'random' number from 0-9? A shortcut programmers take to do that is to divide by 10, then check what the remainder is. By remainder I mean for example 11 doesn't divide evenly into 10, it has a remainder of 1. 23 divided by 10 has a remainder of 3, etc. So our new function is \"(X*123)%10\" You're probably used to seeing % to denote percentages, but in coding it is shorthand for [modulo]( URL_0 ) which just is a fancy word for asking what is the remainder when you divide by a denominator. So now: Plug in 1 for X and we always get 3 Plug in 2 for X and we always get 6 Plug in 3 for X and we always get 0 This is a bit better of a random number generator than our original function. The results jump up and down like we would expect rolling a 10 sided dice would do. Unlike dice rolling, all the answers are still deterministic. The same seed always produces the same output. It can become an even better 'random' number generator when we take something that's changing all the time to use as the seed, like asking the computer what the current time is. So if it's 4:45am the program could plug in 445 for X and get 7. Mindcraft is understandably a bit more complicated than that. It's generating bioms, items, and other things. It still doesn't make anything truly random though. It just takes a given seed and does some program functions it designed specifically to *seem* as if it generates random environments.",
"In the computer science world \"Random\" is a white lie. There are functions that look like there generate random sequences, but as long as you feed in the same input each it, it will generate the same numbers. This number is the seed. Normally, time is used as the seed, so a different sequence is generated each time, but if you want to generate the same numbers each time, give it the same seed.",
"All random number generators are only pseudorandom, aka fake random. All programs are just step by step instructions that the computer follows. You give the computer an input, the computer will follow the steps and give you an output. Because the instructions the computer is reading doesn't change, it can't ever produce truly random numbers. All we can do is change the input to generate different outputs. For RNGs, the input is the seed. If you give it the same seed, it'll follow the instructions and give the same output every time. If you don't give a seed, then it'll automatically look up something that changes a lot and uses that as the seed instead, like the current time.",
"The trick is that they aren't actually 'random' generators. Instead, they are just mathematical sequences that change depending on the starting number. The seed is just that starting number, and any 'random' generation is really just taling the next number in the sequence and examining it."
],
"score": [
8,
7,
6,
6,
4
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/Modulo_operation"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gzjyz4
|
Photorealism vs VR?
|
Why is it not possible to simply use photos in digital media? Why can't you just copy pixels from a photo or 3d photo onto a digital avatar and animate them so they look like a real person? What is the technical difference or limitation preventing that? If you can edit or fake a photo in photoshop why can't the same thing be done with disney movies and video games? In what way are pixels in a picture of the real world different from pixels of the same scene created in a 3d modelling program? What makes them not interchangeable or easily swapped? Hopefully this question makes sense, I've tried to explain what I'm really asking in three different ways, rather than ask three different questions, in case that wasn't clear.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftgmj2d",
"ftgo1sa"
],
"text": [
"First off, if we talk about 3d animations, in a lot of cases we have lighting going on, that implies to set up a virtual light source and most of the surfaces to have a coeficient of reflections, than there is the depth, a image is only a texture, while a drowing is a 3d map of points filled with a texture, but on 2d, it's the dificulty of animating probably, the harsh of creating realist movement and flow of body",
"Our brains and senses are fantastically good at certain things. Although we don't notice every detail of shading, motion and texture, somehow it is very difficult to fool most people with a simulation. The simulations always seem \"off\" to us even if we cannot pinpoint exactly why at the moment. This makes it very difficult to artificially create realistic moving objects and that is not even counting realistic environments which are many many times harder. In the environment you have to consider things like shadows, reflections, perspective, the way colors change in different light, hair movement (very difficult!) etc. Plus for something like a human body, each joint articulates a particular way, muscles move a certain way. These all seem like minor details but when they are missing or wrong, our brains somehow very quickly detect the differences."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gzmshy
|
Processors and the significant of different architectures
|
How is and i7 different from an ARM processor and how do apple processors differ (A12, A13 etc). I read in an article that they can be taylored for different uses and I'd like to learn what exactly it is about them that makes them better for one purpose or another
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fth1t24",
"fth4btk",
"fthfnz3"
],
"text": [
"The biggest difference between x86-64 CPUs (Basically every desktop CPU for 20+ years) and ARM-based CPU's is the instruction set. The instruction set is essentially the list of individual commands that the CPU can do (operations like ADD $1 + $2, or JUMP to $1). ARM uses Reduced Instruction Set Computing (RISC), which means it has a very simple CPU design with very limited individual instructions. x86 uses Complex Instruction Set Computing (CISC), which allows it to do more intensive operations, such as directly manipulating data in memory without having to load it into the CPU. The CISC architecture means the CPU is significantly more complex to engineer and build, but in any single instruction it is able to do more. However, this costs more power, and as a result also generates more heat. For a mobile phone, the lower power usage and heat generated by an ARM CPU is a significant design decision. For a general purpose desktop computer, the raw power of an x86 processor allows it to accomplish more.",
"The thing is, not many people are aware, but ARM doesn't manufacture their processors (on a commercial scale). They design and test them and then licence them to costumers, alongside with other components like GPU's, memory, debug system, etc. The apple processors are ARM-based, so the base of the architecture is the same, but they add their own things, like AI engine. Officially it's a trade secret that Apple uses ARM design as a core, since neither company made a public statement about it (or did back in 2015 when I was working for ARM) . Intel does design and manufacture their own processors for commercial sale. For your actual question: They have different design choices. The i7 for example values performance over energy consumption since it's mostly used in desktop systems without batteries, while ARM processors are mostly used in mobiles and IoT devices, where you almost always use a battery (and you don't need that much computational performance for e.g. running games). ARM is based around low energy consumption, that's how they got started, back when they did the BBC Micro for schools. Those processors are capable to go into very low power consumption states (sleep, deep sleep) where they can go as low as 1 micro Amper, so that battery usage is at a minimum. Think of it as a sensor that measures something in a field, where you just can't change the batteries on a daily basis. Most micro controllers use them. Intel (and AMD) is much more focused on computational performance, doing much more in a shorter time. Since you'll be mostly using them on a desktop or server, energy consumption mostly just a second thought. Have you ever looked at a CPU datasheet to check how much power it needs? Probably not. Also as added note: These are general purpose CPUs. You can do a wide variety of things with them, but only \"mediocrely\". There are dedicated processors like DSP's (digital signal processors) or even GPU's (graphics processing unit), which are optimized to do some particular calculations very very fast. GPU's of course do graphical calculations very fast, which are mostly matrix additions, multiplications and all kind of vector transformations. DSP's have MAC (multiply and accumulate (add)) commands, since those are the basic elements for discrete signal transformations. They are useful for example for converting audio codecs on a large scale in real time.",
"You had a lot of good responses so far, let me give a little more color to some of it. Networking equipment, a lot of it, uses a chip called a \"Trident\" which is manufactured by Broadcom. So this chip is capable of supporting something called an \"ASIC\" which can get confusing - so let me explain it like this - the chip is designed with circuits that can move network traffic without a lot of software code. This means it can be 'wire fast', little overhead from someone needing to code logic. That processor is totally inappropriate for a laptop that needs graphics ability. You can run networking equipment on a plain old intel chip (and some do) but those tend to be a 'linux server with ports', in order to replicate the performance of the Trident processor you need a bunch of software and a much, much, much faster processor to handle the traffic. There are valid reasons for adding this complication, but we won't get into that. Easier example, \"Intel with MMi\", that processor can handle both the typical I/O of a computer and it has specialized circuits to put multimedia on a screen. Intel still makes these, so you don't necessarily *need* a specialized graphics card to see things on the screen. TL:DR; chip designers will put features in chips that are specific to common tasks."
],
"score": [
22,
8,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gzxjze
|
Why do gaming computers download and install updates incredibly quick while consoles mostly take hours ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftiv857"
],
"text": [
"It all depends on where you're getting the update from. All console traffic goes thru their respective service, so its limits by their speed. Pcs are getting their downloads straight from the servers with nothing in between."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gzyk79
|
If multiple people are using 4G, are they in a LAN with a satellite as the host?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftj0shk"
],
"text": [
"No. The \"L\" of LAN means \"local\" and a satellite in space isn't geographically local to you. Also, cell networks use cell towers, not satellites."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gzz2sy
|
How there are multiple internet providers that all use the same cable in an apartment, but some providers can offer higher speeds than others even if it is the same cable.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftj8c69"
],
"text": [
"There's one company that put the cables in the apartment and owns the cables. But the cables go to a data centre nearby, and the cable company has some routers there which split out the individual connections again, and everything after that belongs to your internet provider."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h02tam
|
How come changing the pitch of a voice makes someone anonymous
|
Can't someone just download the audio and make the pitch normal and find out what the actual voice sounds like.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftjt2cp",
"ftk1rvs",
"ftjskjo"
],
"text": [
"I attempted this with a voice clip that I once had. The restored audio is surprisingly pretty close. But you tell me & #x200B; Original: [ URL_2 ]( URL_2 ) & #x200B; Pitched Down [ URL_1 ]( URL_1 ) & #x200B; Attempted Restore [ URL_0 ]( URL_0 )",
"youd have to guess what the normal pitch is, which would make it harder to guess who the person behind the voice is. and also as someone else pointed out, this process inherently reduces the audio quality.",
"So if you have an ID number that tells us who you are. That is incredibly close to a bunch of other people's. And you change that id number by adding another number and using the sum. People trying to figure out your ID wont know the number that you used. If they guess the wrong number they find a completely different person. So if they dont know how exactly you changed your voice it can be hard to recreate"
],
"score": [
4,
3,
3
],
"text_urls": [
[
"https://voca.ro/odAluYu0BXv",
"https://voca.ro/ocvYKD9DI2b",
"https://voca.ro/eyeG2MQ2Soe"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h04vuq
|
How do pulse Oximeters work?
|
I always thought actual blood would have to be tested to find out oxygen levels. How does a pulse oximeter find blood oxygen % without accessing the blood?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftk5ouq"
],
"text": [
"Most of them use red/infrared light. When haemoglobin in the blood absorbs oxygen, the molecule’s physical property changes and it absorbs different wavelengths of light at different amounts than before. The standard wavelengths tested are 660nm and 940nm. There is a significant difference between the percent of light absorbed at these wavelengths by oxygenated and non-oxygenated haemoglobin. By shining both wavelengths of light through skin, and measuring the percent of red light absorbed vs infrared light absorbed, you can work out the oxygen content of blood."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h0acj2
|
how do we transmit internet using light?
|
same question kinda applies to electricity as well. I don't really understand how computers can transform light particles into information, and vice versa. And why optic cables are faster than copper cables? isn't internet just a certain size of data you have to transmit, wouldn't the speed be the same for both cables?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftky511",
"ftkyb9m",
"ftkybkm",
"ftkziaj"
],
"text": [
"Computers speak in binary. Zero or one. The way to look at it in relation to light is, on or off. That's all it takes, either there's light/electrical signal or not. Also, there's resistance in electrical cables, some metals more than others, gold being the least resistant of the metals. With light there is no resistance but I believe there's still a power drop over distances.",
"Computers don't transform anything into information. Humans do that. All computers do is manipulate things like electricity. For example, take a computer program that outputs the statement \"Hello World.\" Crack open that computer and you won't find \"Hello World\" anywhere to be seen. Now, you might say that that's because computers operate in binary, 1's and 0's. And indeed, each character of \"Hello World\" can be mapped to a binary number. But crack open that computer and you won't find any 1's or 0's either. Even that assignment is man-made. What you *will* find are components storing electricity at various levels of voltage. We can group these voltages into high voltage ( > 0.5 volts) or low voltage ( < 0.5). It's those high and low voltages that humans assign meaning to. At the first level 1's and 0's (for high and low voltage, respectively) and then greater meaning (such as assigning sequences of 1's and 0's to numbers and letters and other symbols). All the computer does is take sequences of electronic pulses at given voltages and turn them into other sequences of electronic pulses at given voltages. We can also make this assignments to other things, like magnetic fields (as with hard drives), light and dark spots on a reflective platter (as with disks) and pulses of photons (as with fiber optics). In terms of \"speed\", while electricity itself moves around the speed of light, the wire it moves down provides resistance, a sort of electrical friction. This degrades the signal over time putting a maximum distance it can travel before needing to be boosted. Also, the copper cables take up more space than fiber optic cables, so fiber optic cables can send more information at the same time than electronic cables. So even if they were the same \"speed\", the fiber optic cable is still sending more information \"faster.\"",
"Ok let's use an example. You and I are standing on the opposite end of a dark tunnel and we each have a flashlight. It's really loud so we can't yell so we agree before hand that we will use morse code. So let's say I run into trouble and I want to tell you SOS. In that case I blink my flashlight 3 times fast, 3 times slow, 3 times fast. [ URL_1 ]( URL_0 ) & #x200B; Now since we AGREED that that was how we would send a receive information, we can both understand it. In the case of the internet, whether you use electricity or light is actually irrelevent. The internet is just information. On both ends of the wire, you have two computers that have agreed about how the information would be sent and how to read it.",
"I think there are 2 main parts that I can try to answer. A computer at one end basically converts information into a signal that uses light to transmit. It would almost be like Morse code with a torch. At one end the computer causes the light to flash to send a particular message and at the other end the receiving computer interprets the light flashes (which is then translated). Information through a wire travels at the speed of light in that material. I believe the speed of light in copper is slightly faster than that in fibre. Fibre suffers from less interference (as it uses light instead of electromagnetic signals) and generally can be run further before the signal starts to die down. These are some of the factors that mean fibre can transmit more information (or information faster)."
],
"score": [
10,
6,
4,
3
],
"text_urls": [
[],
[],
[
"https://www.google.com/url?sa=i&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMorse_code&psig=AOvVaw1Z3uidvzbhtpzIZcbTddZH&ust=1591880677625000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCODXk-Wn9-kCFQAAAAAdAAAAABAD",
"https://www.google.com/url?sa=i&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMorse\\_code&psig=AOvVaw1Z3uidvzbhtpzIZcbTddZH&ust=1591880677625000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCODXk-Wn9-kCFQAAAAAdAAAAABAD"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h0ax7y
|
Why are movies shot in 24 fps rather than 30?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftl1joe",
"ftlkege"
],
"text": [
"Back in the day, the film was an actual significant cost. They wanted to keep the amount of film use to a minimum. 24 FPS is the lowest you can go before you start to see single images instead of rolling frames.",
"So your eye naturally adds motion blur to moving objects in the real world. Try wiggling your finger back i front of your face, you'll see it blur. If, for example, you filmed your hand waving at 100FPS and watched it back on a screen, what you'd find is that there's no motion blur and it'd look unnatural. This is because when you look at a moving object on a screen, your eyes are not tracking an actual object in 3D space, they're looking at flat, stationary screen. The reason we choose to watch at 24FPS is that when we do, your eyes will recreate that motion blur on a flat screen and give you the feeling that it was filmed in the real world. In movies that are viewed at 60FPS they actually have to add motion blur between frames during the editing so that you don't notice. This is also the root of that stupid saying: \"the human eye cant see faster than 24 fps\", when in fact it should be something more like \"filming in 24FPS most closely matches how the human eye perceives movement\", but that's not nearly as catchy"
],
"score": [
19,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h0c6t1
|
Can you please explain to me the business model of 'Brave' browser?
|
It seems to me it uses 'Basic attention token' for users to opt in to receive advertisement. Does that mean one can earn money simply by watching ads in Brave?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftl8ktw"
],
"text": [
"Brave blocks ads, and then lets you opt in to getting THEIR ads. They give you a token currency for viewing ads, and the keep the income from the actual ads that are generated. They then give the user the option to forward their token-currency to websites that sign up to the Brave Content Creators program for support. Essentially, you can watch ads to support specific websites that you want, but Brave takes a share."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h0e1d7
|
Why is it that windows in most video games are opaque and not transparent?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftlij65",
"ftln8ku"
],
"text": [
"It’s an easy way to reduce processing overhead by not having to render the scenery and process lighting/effects through the windows. Also, depending on the game, it gives some blind spots for the developers to hide enemies, etc.",
"I do 3D design and can confirm, transparent windows have so much more to render. It’s simple and intuitive for us to think about, but to a computer, it has a lot more information it has to assemble, which takes more time, which makes the game lag or slow. Making them opaque is just a simple way to prevent that lag"
],
"score": [
14,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h0ifwj
|
How can battle royale games put 100 people in a game at once with minimal delay, but fighting games struggle to connect 2 people together without lag?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftmag0l",
"fto3ekl"
],
"text": [
"Fighting games have you connect directly to eachother, one person with their normal connectivity is then hosting both players. That’s where “host advantage” comes from, supposedly being the host gives you a smoother connection than someone piggybacking online from somewhere further away.",
"Shooting games can have a lot of prediction, because people are usually running in a straight line, and a \"hit\" can take the known or estimated position and angle of the shooter, and combine that with the previously known or estimated position of the target. This is why when you do get major lag, you see people rubber-banding all over the place. Fighting games don't have this luxury, as there are so many different possible moves at any one time, you cannot say \"well our ping is 100ms, and that player was moving in this direction so lets place the character where they will be in 100ms\", you have to wait that 100ms to find out exactly what they did to know what to display."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h0iv5j
|
Why does a gaming console (or other computer system for the matter) have to restart to apply an update?
|
When I update my PS4 it always requires a restart to apply the new software. Why is that? It seems odd that power must be turned off and then on for the system to do certain things that it seems like it should be able to do when it is running? What is this process? Edit: Thanks for the responses, makes sense.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftmbnqs",
"ftmbkf0",
"ftmbtgv"
],
"text": [
"Essentially, you can’t change software while you’re using it, so it prepares everything it can and then turns off, stopping the software being used, and the final changes can be made. It can then restart using the new software.",
"There are certain key functions in the base operating system that need to be updated, sometimes it's a security patch, or something else behind the scenes that simply cannot be updated to the new version without a full restart. The only ones that generally do not have this issue is some server implementions of Linux since everything is separated into its own process which is why some of them can run for years without a reboot, although a good server admin still does so every 30-90 days anyways.",
"For 2 reasons: A) Certain files it is trying to update are being used (because they're core system files) so they can't be modified if they're being used and B) To ensure nothing is running that could interfere with the update and maybe break/mess with it. That's why it's the first thing that happens when you turn it on."
],
"score": [
10,
6,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h0kczt
|
How do the dinosaurs in Jurassic Park still look SO good after 27 years?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftmkjxy",
"ftmkwyh",
"ftmmtwz",
"ftmv6ou",
"ftmxpu6",
"ftmww0t",
"ftmpncn"
],
"text": [
"A lot of it is animatronics, and otherwise it’s a matter of knowing what the capabilities were, and designing shots that played to that.",
"A lot of real effect like animatronics, but also they designed the scene to hide a lot of the limitation of CGI. Most scene are in the dark, short, not a lot of movement, so you don't notice the mistakes as much. One of the biggest limitation of CGI is time, and so if the studio don't leave enough time for the CGI, it will show. For exemple, the final fight in Black Panther was reshoot, leaving very little time for the team to do the cgi on it and it show.",
"CGI gets old, like in 20yo videogames. Animatronics/puppets/models remain the same. The same thing happens with Star Wars starships effects or 2001 space odissey. They used scale models and they still look super good",
"Watch the Corridor Crew video on YouTube about it, it explains it really well and shows you the scenes. It’s mostly a mix of animatronics and smart use of simple light sources.",
"One of the major reasons they look so lifelike is they move in a lifelike manner. How did they do this? Spielberg gave paleontologists access to computer hardware which was outside of their normal price range (I think it was around 100k a pop and a lot were used) and gave them funding only dreamed about in academia to recreate dinosaur movements. This film greatly expanded our knowledge of dinosaurs. After the data was obtained highly skilled visual effects people took this data and constructed models which were scanned by laser to create the animation wire models. Texturing and such was done using information on musculature and so forth. Basically science and the film industry worked together to build dinosaurs from the ground up rather than winging it as had been done in the past.",
"Damn I thought this was the weekly r/movies post that asks the exact same question every time lol",
"When they used CGI they paired it with practical affects. Things like the animatronics, having the hanging skeletons move when jumped on or bumped, having other objects moved like the car being pressed into the mud, etc. They also tended to use the CGI either in dark areas where the shortfalls of the tech were harder to see, or in short bursts (such as the raptors jumping) which involved either rapid movement or switching camera angles which once again hid many of the shortfalls of the tech."
],
"score": [
177,
23,
6,
5,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h0nm58
|
Why can computers play multiple audio sources at once while phones (usually) have to turn one source off to play another?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftn4tg6",
"ftn5nwg"
],
"text": [
"In a word, software. Computers will let you do this natively whereas Android and iOS don't (usually.) However there are apps for both that will let you play multiple files at the same time. To show that the phone can definitely play multiple files together just play a game, multiple audio files will play together all through the game.",
"Phones are designed to keep everything simple. It is assumed that when you are talking on the phone, you want the music to stop, for example. The phone is just as capable of doing both at once, but it is not set up to do it because most people would find it confusing or frustrating."
],
"score": [
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h0snaj
|
Why do GPUs require frequent driver updates whereas CPUs do not?
|
It seems like every time a AAA comes out Nvidia and AMD always have driver updates for their GPUs and without those updates the game usually doesn't play as well. Why is this needed for GPUs but not CPUs?
|
Technology
|
explainlikeimfive
|
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"CPUs have very standard instruction sets. All AMD and Intel CPUs pretty much use the same instruction sets, though sometimes there is a little bit of differences, but not many. So games can just compile themselves and they'll easily run on all AMD and Intel CPUs without any changes. GPUs are not like that. Nvidia and AMD make vastly different families of GPUs. And even outside of the same family, there is vastly different functionality of the GPUs. A game maker can not optimize it's game for every GPU out there, it's just impossible. So they interface with a common interface normally, DirectX, and hope that DirectX does well at displaying their game. The GPU manufacturers want their GPUs to perform well and sell well, so they go ahead and make a new version of the driver that detects the new game and optimizes the interface between DirectX and the GPU so that the new game performs well. They don't have to do this, but if they don't gamers won't buy their GPUs. Think of it as your car. If you drive your car on the highway, you can buy tires for it that are meant for the highway, and it will perform well. But if you need to start driving in ice and snow, well those tires might not perform that well. So you can buy different tires that perform well in the ice and snow. You are still driving the same car. Just have a different version of the tire now.",
"The new driver has specific tweaks *for that specific game* to try and make the game run faster. Nvidia (and AMD) do this because it makes the numbers look better so more people are likely to buy their graphics cards. For example, if the game asks the graphics card to do something it doesn't actually need to, because of a programming mistake, the driver update may tell the driver to just ignore that thing entirely. For another example, it may tell the graphics card to use less accurate maths for some things.",
"The simple answer is that CPUs don't have drivers, so there's nothing to update. Strictly speaking though, the driver is just a layer of software that sits between the Operating System and the hardware (in this case, the graphics card/GPU) and interprets commands from the application/OS into the machine language spoken by the GPU (the instruction set). So if something needs to change to make this more efficient when running certain games, add features, or fix a bug, the drivers need to be updated. Graphics card manufacturers want you to prefer their product over others, so they have an incentive to work with game developers to fix any compatibility issues or squeeze every bit of performance for certain use cases, which is why there are constant driver updates to coincide with new game releases. Drivers are only needed because an OS can't reasonably be expected to know how to talk to every single current and future piece of hardware. Though it will usually be able to communicate in a standard, limited way, which is why you can still go through the Windows install GUI on a new machine before any drivers have been installed. The best people to know how to talk to a piece of hardware, is the maker of that hardware, so drivers are a way for them to control that interaction. On the other hand the OS is talks to the CPU directly; the concept of a driver doesn't exist, but under the hood the OS is doing a very similar things - interpreting software commands into the machine language spoken by the CPU (x86 instruction set, usually). OS's have been around longer, and CPUs haven't changed much architecturally, so this layer doesn't often need to change. But occasionally it does need updates, so they are included in OS updates."
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h0yj6k
|
Why is the colour standard in RGB if the three primary colours are RYB?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"It's not RYB, but CMY (Cyan, Magenta, Yellow). The difference is important. RGB is an additive model: You add colors, and all colors at once add up to white. CMY is a subtractive model: You absorb colors, and absorbing all colors gives you black. That's because unlike a monitor, paint doesn't emit light, so the only thing it can do is absorb or not ambient light, and reflect the rest. Cyan is blue+green, or paint that absorbs red. Magenta is red + blue, or paint that absorbs green. Yellow is red + green, or paint that absorbs blue. In printers you normally see CMYK, where K is black, because in practice mixing CMY together produces a muddy brown rather than a pure black, and because black ink is cheaper. Specialized printers can have more inks, for instance CcMmYK, that provides additional lighter cyan and magenta inks for better color reproduction."
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h0ylo4
|
How did people start measuring distance at sea where it's water all around?
|
Today I know we have the technology to position anything accurately within a few feet. But how would sailors in old times measure distance and have maps of the sea? Why is there a nautical mile and different from the land mile?
|
Technology
|
explainlikeimfive
|
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"This was a massive problem for ancient mariners - with no landmarks you were totally lost the moment you lost sight of shore. Eventually two breakthroughs enabled open sea travel. The first was the discovery of magnetic stones, and the concurrent discovery that the Earth itself was magnetic. This lets you build a compass and find north no matter where you are. The second is the development of celestial navigation. There’s no *land*marks at sea, but on a clear night the sky fills with hundreds of them. If you know what day it is and approximately how big the Earth is, you can chart what stars should be visible from what points on the globe and in what direction. Following the sun, moon, and stars with the aid of star charts and a compass was the complex but accurate method pre-industrial sailors used to reach their approximate destination across the open ocean. Once accurate maritime clocks were developed the system became extremely accurate. If you know exactly what minute it is and know exactly when stars *should* rise and set at a certain location you can determine how close you are with high accuracy. Of course, this all requires clear skies. Many ships lost course in stormy or overcast conditions and ended up way off target.",
"The simplest way to estimate distance run is to measure your speed, and multiply by the amount of time spent at that speed. This is called dead reckoning, and is still an important part of navigation, it's the only way submarines can navigate while submerged for example. The old way to measure speed was to have a board tied to a rope. You would drop this board over the back of the boat, and let the rope pay out. The rope had knots in it, so by counting the knots that passed through your hands in a fixed time, you found the speed. Hence the unit for speed at sea is the knot (1 Nautical Mile per hour). A nautical mile is not an arbitrary length, it is the distance on the surface of the Earth of 1/60th of a degree of Latitude. So if a boat sails North 1 degree it will have traveled 60 NM. 1/60th of a degree is called a minute, and charts are marked in degrees, minutes and decimals of minutes. It is easy to measure distance in NM from this scale using a ruler or pair of dividers (the classic navigation tool). The other thing to remember is that distance is often not terribly important in sailing, so long as you are going in the right direction (using a compass), you will eventually reach your destination. Of course over really long distances the errors start to add up, which is why celestial navigation and then GPS were invented.",
"A piece of wood attached to a long rope which had knots at set distances. The rope had for four attachment points; two at the top were fixed, bottom were fixed with pegs. The board was thrown over the side and the board acted as a anchor. As the ship moved forward and the rope played out it was timed. The number of knots counted. How many knots passed determined the speed - 6 knots. When the time was expired the rope was tugged to release the pegs and the board hauled in. Which is why speed at sea is measured in knots.",
"First, a \"land mile\" is the amount of distance traveled regardless of escalation. This doesn't work at sea due to waves, the ship is moving up and down all the time, so they had to come up with a way of measuring only forward distance. At sea in harsh conditions, you might be traveling at a speed of 10 MPH, but making no forward progress at all due to the waves. Back in the day, sailors had a couple of different ways to determine things like that depending on where they were. In the Mediterranean, for example, they would often just stay in sight of the coastline. Many of their coastal buildings were built in such a way as to align with the rising and setting of stars and equinoxes, so you could roughly tell where you were and which direction you needed to sail away from if you were headed to Egypt or something (because that was more than a day's voyage, so you had to sail at night across open water with no landmarks). You've got your celestial navigation dating back to at least Ancient Greece (as noted in Odyssey), where they'd keep a certain star at a certain angle away from the ship using a sextant to measure the angle, which could keep them moving along a straight latitudinal line. Later on we developed the astrolabe, magnetic compasses, kamals, clear sunstone, and I'm sure I'm missing some others. All these assisted navigation in various fashions when just looking at stars wasn't an option. And of course, all that time we had cartographers on ships and on land, drawing everything out to a remarkably accurate degree. Making accurate maps was a profitable endeavor due to the increasing need for maritime travel.",
"Measuring speed through water is easy. You take a rope, tie knots into it at a fixed distance from each other, tie it to a bucket. Now, you can toss the bucket into the water, flip a small hourglass, and count how many knots get dragged out before the hourglass runs through. That's why nautical miles per hour are called knots. There are many different miles, derived and standardized in different ways. Nautical miles are standardized as an angular minute (1/60th of a degree) along the earth surface, because that makes calculations/navigation more convenient. Now, I mentioned speed *through water*. The problem is, the water could also be moving. If you're moving at 5 knots (through water) towards north, but the water is flowing south at 1 knot, you're actually moving at only 4 knots relative to ground. The way to correct that is to get a *fix* - determine your position. You can do that for example by sighting two landmarks, measuring the angle at which they are seen (if you have a sufficiently accurate compass), drawing those lines on a map, and seeing where they intersect. For example, if you see a tower straight north, you can draw a line south from the tower on a map, and you're somewhere along the line. Draw a second line from a tower that's to the west, and the lines will intersect and that's where you are. Far away from land, you can also use the stars. But what if it's overcast? You're kind of screwed. You have to measure your speed through water, guess the current, calculate your guessed speed over ground, and then from that and your last known/assumed position, calculate where you're now. Say you think you're moving north at 4 knots, then every hour (more often in practice), you'd go to the map, measure 4 miles from your last position, and mark your new assumed position. This is called dead reckoning, and is about as accurate as it sounds, especially as every mistake adds up over time. You better be accurate... because you can't see underwater obstacles, and if you miss an island, you could get lost until you can get good enough weather to get a fix again. Ships sinking is bad for business, so governments invested ridiculous amounts into getting accurate maps of the coastal waters. On the ocean, it's a bit less of a problem, but it's good to know where you can find an island to get some fresh water, food, and much needed rest, so those were also mapped (based on whatever position information was available). Obviously, this all royally sucks. Thus, humanity applied its collective smarts, shot atomic clocks into space where they fly around at a speed of around 14000 km/h, broadcasting the time. Your phone can receive the signal, and from the time in the signal can deduce how long the signal took to get to you, and thus how far you were from the satellite when it broadcast the time. Combine this with the knowledge of where exactly the satellite was at that time (which is a separate problem in itself), the time and position from 3 other satellites, and some relativistic math, and you have your exact position, whether the sky is clear or not, and don't have to rely on dead reckoning anymore. That's how GPS and similar systems (GLONASS, Galileo, BeiDou) work. (Before satellites, there was a ground radio based system called LORAN, because it's a *really* annoying problem.)",
"Knots! [ URL_0 ]( URL_1 ) *Knot is one nautical mile per hour (1 knot = 1.15 miles per hour). The term knot dates from the 17th century, when sailors measured the speed of their ship by using a device called a \"common log.\" This device was a coil of rope with uniformly spaced knots, attached to a piece of wood shaped like a slice of pie. The piece of wood was lowered from the back of the ship and allowed to float behind it. The line was allowed to pay out freely from the coil as the piece of wood fell behind the ship for a specific amount of time. When the specified time had passed, the line was pulled in and the number of knots on the rope between the ship and the wood were counted. The speed of the ship was said to be the number of knots counted.*",
"The stars generally. You can approximate your north/south position without any tools, and most ships stayed within sight of land even when making long journeys. IE before the development of the sextant and accurate time keeping devices to plot longitude, most ships were never on open water for extended periods of time. The reason you need accurate clocks for the plotting of east/west longitude is because you have to compare the position of the sun or stars at local time, to the time at your home port (such as GMT) and in order to keep track of the time at your home port you needed an accurate time keeping device. The problem was that early on, most accurate clocks used pendulums which did not work well with ships that bobbed and moved around. A grandfather clock only works when it's on flat, stable ground, not on a ship that can tilt in any direction. Another measurement that was important for determining distance was speed as well as time. If you know how fast you're going and how long you've been traveling then you can approximate the distance you traveled. This wasn't precise because both wind and water could move, so while the ship might have moved 100 miles through the water, it might not have moved 100 miles compared to a fixed point on land. Speed was measured in several ways but a common one was to use knots tied in a length of rope at regular intervals. The rope was tossed overboard and allowed to play out it's length and how many knots it played out in a given amount of time gave the boat it's speed through the water. We still give speed in water in knots.",
"ELI5: Distance = speed * time. They would measure time, guess speed, and calculate a distance. ELI55: Read some of the other posts on here. Seems everyone forgot what the \"5\" stands for in \"ELI5\"...",
"Others had commented on astrological/celestial navigation but the real advances in exploration happened after John Harrison's invention of the \"marine chronometer\". The Marine Chronometer accurately kept time at sea which was important since you can calculate your longitudinal (east-west) position based on the time of the clock and high noon. Because the earth is 360 degrees and we have 24 hours a day, that means every hour of travel is 15 degrees of longitude. By measuring the gap in time between high noon in your current sea position and the clock you've sent to a \"standard time\" (Greenwich Mean Time), you can calculate how far east/west you've traveled. For example, if high noon on your ship occurs at 1 PM on your clock, you know that you've essentially traveled 15 degrees since the difference between high noon and your clock is one hour.",
"Hey, I can chime in on this one. A few years back I read a relatively short, very interesting book called \"Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time\" With several navigation techniques sailors had been able to keep track of which latitude they were currently at, but longitude was a big issue. Before a working device to track longitude was developed, sailors destined for across the Atlantic would \"sail the latitude\" and basically just point themselves at the new world and keep going until they hit it, with only estimates about how much time it usually took to cross. They could estimate very roughly where they were based on how long they'd been sailing, and what conditions had been like on their voyage, but until an accurate device for measuring longitude came about they were literally \"at sea\" until they hit land, which is where the term comes from."
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h16gi8
|
Why is it that when electronic devices malfunction, turning them off then on works so frequently?
|
E.g computers, Wi-Fi routers, tvs, consoles. All these items malfunction every once in while and all I do is turn them off then on again to get them working again. Why?
|
Technology
|
explainlikeimfive
|
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"Most electronics work via a chip that has memory of what it is supposed to do. Like a set of instructions. Sometimes it gets overwhelmed and loses its place. When you turn it off and back on, you reset it to start back at step one, so now it knows its place and what to do next.",
"Imagine you've been given a set of 50 directions to follow. You got one step wrong, but you don't actually know this until you've completed all 50 steps and aren't where you should be. You're given 2 options - retrace your steps to try and figure out where you went wrong, or just start again from the beginning. Restarting your device is equivalent to starting the journey again. Except your device is running millions of instructions, and sometimes it's near impossible to figure out which of them went wrong, and it might not even be possible to fix it.",
"* Devices like these are tested before they are released. * The makers try their best to test under many different circumstances. * However it's impossible to test them all. * After a device is running for a long time, it's possible some combination of values causes a previously unknown error to cause the device to freeze up. * Restarting it resets all the values in memory and returns the device to its starting condition which is a state that has been tested very thoroughly.",
"Rebooting a system generally gets it to a known state. That is easiest to test, and bugs in there are often found and fixed. Sometimes a combination of variables can get a system into a state that contains a bug. That bug might not allow you to return to a good state, or you might not know how to. The bugs can range from a variable overflowing, to memory leaks, to bad code paths in the source code.",
"Usually there is a set of processes that start and work in unison when a device is first powered on, from simple to complex. Sometimes there can be issues that arise after one of those processes fails or becomes unstable. Well designed systems will start and recover those components, but sometimes a reboot or power off, is the easiest way to get things back into a cleanly started and stable state.",
"Computer programs, pure and simple. In your device are programs that make it behave the way you need it to. And those programs aren't perfect. ANALOGY: You're in your car, following a sheet of written instructions on how to get to your destination. They're extremely well-written, but just at the point where it says \"turn left at the house with the red fence\" your view gets blocked by the biggest truck you ever saw. So you don't see the fence and you miss the turn, and it's 10 minutes later, and you're lost. And the road is narrow - you can't even turn around and go back. You're not going to where you ought to be any time soon. BUT! On the steering wheel is a Big Magic Button marked, \"Start over!\" You push it, and - wow - you're back at the start of your journey. Now you can follow the instructions again. And this time there's no truck, you make the correct turn, and you get to where you want to be. Computer code is a bit like that. It has the places it's supposed to go. But there are ALWAYS bugs in code. And sometimes, things happen in just the wrong ways, and suddenly the code is heading off into new and wonderful places that the people who wrote it never intended. It's hopelessly lost, and there's no way it's finding its way back. But - you have a Big Magic Button. You turn it off; you turn it back on again. It forgets what it was doing, and starts again at the beginning, the way it always does when it's turned on. And likely goes where it's supposed to go, and hopefully doesn't get distracted again (for a decent while, at least). Always worth a try, basically.",
"Most electronics have two types of memory: persistent (think your hard drive) and temporary (think you RAM). Programs are stored in the persistent memory, but anything they run or calculate is stored in the temporary memory. You change menu? That's in the temporary memory. What is visible on screen right now? Temporary memory. So if there is a bug in the program, it means that some wrong information has been written to the temporary memory. Maybe you've executed a very specific sequence of instructions that cause an unexpected piece of the code to misbehave. Restarting the electronics allows you to back to a \"blank slate\".",
"Computers are state machines. This means that each operation they perform assumes a given state, expects a certain type of input, and produces an expected output. If the state of the machine is not as expected, the result will not be reliable. An invalid state can arise from multiple issues, such as malfunctioning hardware, or unexpected input. Since the state, and thus the operation of the computer, is largely dependent on each operation proceeding it (eg. the output of an operation operation at step 1 is used as an input in step 4), then errors can compound and at some point the process will not be able to proceed or recover. Resetting the device puts it back into a known good state (it clears any memory and goes back to step 1). As an analogy, if I gave you a list of directions from A to B that were like, \"take 2 steps right, 4 steps forward, 5 steps left\" and for whatever reason something goes wrong - maybe you counted the wrong steps, or it rained last night and I didn't account for a puddle on the path you had to go around - then if you keep following the steps I wrote at some point you're going to realise something is wrong. You could try to work backwards to fix any errors, but that assumes you even know where the error occurred in the first place. So your best bet is to go back to A and start again."
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h16xhd
|
How does facial identification work on I phones? I shaved my head and started to wear glasses..
|
And the facial ID still works. How does it still know it’s me?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Many recognition systems use reference points on your face and measure the distance between them. Tip of your nose, corners of your eyes, tops of your ears etc. If the structural dimensions of your face match up, you're in! Glasses and hair don't have an effect, cosmetic surgery or a deformative injury may."
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h16znu
|
How is the height of very high mountains measured accurately?
|
Technology
|
explainlikeimfive
|
{
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"ftqd055"
],
"text": [
"Today they just go up there with a GPS receiver or scan the earth with a satellite based radar. Prior to those technologies you could triangulate the height. Create a triangle using the peak of the mountain as one point, and two fixed and known points on the ground as the other two. So long as you have the distance between the two known points, and can measure the angles it's simple trigonometry."
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|
h778aw
|
What makes a jet engine different from a propeller or rocket engine?
|
I have a vague idea that air compression involved but I don't know how this fits together in the grand scheme of things.
|
Technology
|
explainlikeimfive
|
{
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"text": [
"A jet engine works by sucking in air through a series of fans, compressing it, mixing it with fuel, and igniting it. The hot exhaust gases then exit out the rear of the engine, passing through more fans (the turbine) that in turn drives the compressor fans at the front via a shaft. The hot exhaust gases create pressure that drives the engine (and anything attached) forward. A rocket engine works by mixing fuel + and oxidizer to create a chemical reaction, which in turn creates hot exhaust. The major difference between a Jet Engine and a Rocket is that the Rocket has to bring it's oxidizer (air supply) along with it, while the Jet engine sucks in air from the outside. A propeller meanwhile is a number of smaller airplane wings that push air as it spins. So long as a propeller is spinning it pushes air and generates thrust. Propellers can be spun by a number of things like piston engines, or even jet engines. A Jet engine with a propeller attached is called a turbo-prop, and it works by attaching the turbine (the fans in the exhaust) to a drive shaft and gearbox that turns the propeller. By why use a turbo prop instead of a jet engine? These engines are slower, but much more fuel efficient than jets making them ideal for smaller commuter aircraft. The turbines are also much lighter than piston engines creating much more power to weight.",
"Propeller engines aren't actually \"just\" propellers; the important part is what actually drives the propeller, and for larger commercial planes propellers are driven by turbine engines that aren't that different from jet turbines. In any case, regardless of whether it's a turbine or a reciprocating (i.e. like the one in a car) engine, they function by taking in air from the atmosphere, adding a little fuel, compressing the mixture, igniting it, and controlling how the gas expands so as to create rotational power and/or thrust. Rockets work completely differently as they have their own sources of fuel *and* oxidizer on-board (there's no oxygen in space, so if you want combustion you have to bring it with you). For rockets, fuel and oxidizer (together, propellant) are mixed and ignited and then expanded at extremely high velocities through a nozzle, which is then pointed in the opposite direction that you want to go in order to provide thrust. There's no real control in the expansion beyond vectoring the thrust, whereas in other combustion engines you typically get some energy back at the expansion phase that you use to run other processes (i.e. driving the compressor fans in the turbine, keeping the engine running between combustion cycles in reciprocating engines, driving smaller generators that provide electrical and hydraulic power for both, etc.).",
"A propeller is a set of wings turned horizontal and spinning around a shaft. These wings create lift which when turned sideways is instead thrust. A jet engine is a turbine system that has a big fan in the front to intake air and direct it to more fans in the center of the engine that squeeze this air down until it is compressed to a correct level. That air then has fuel injected into it and it is combusted. Combustion creates an expansion and a lot of pressure. That pressure is forced out the back of the engine through another fan blade that is connected to the ones at the front and powers them. This exhaust forced out the back at high speed creates thrust. (Same as a water hose whipping around if you don't hold onto it.) A rocket engine is like the rear part of a jet engine without as many fans. Rockets have to work in space, so they carry their fuel and their oxygen along. These get mixed in the rocket engine and ignited. Same result as a jet engine, the pressure of the combustion is directed out the rear via the nozzle and that force is thrust. The shape of the nozzle helps make the engine work better in different environments (such as sea level for launch, or in the vacuum of space.)"
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h7aand
|
If I leave a charger plugged into the wall but not on a phone or laptop, etc, does it take up/waste energy?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Yes, chargers use induction via a transformers to turn AC power to DC power. This is done using a winding of wire that wirelessly transfers power to a second winding across an air gap without a physical circuit connecting them. In an ideal transformer the electromagnetic field lines form a perfect unimpeded loop between the windings and if there is no draw on the output side you won't siphon any power from the input side to maintain this loop. In reality however these devices are imperfect and flux lines do not always follow perfect paths with no resistance. Instead they randomly bounce here and there creating small eddy currents in the shield that surrounds them, as well as slightly heating up the windings that guide the flux lines. Add to that you can also have low powered LEDs to indicate some chargers are plugged in. It's important to note however that these parasitic losses are extremely negligible. We're talking on the order of $0.05-$0.15 cents per year. If you do the math both the value of even a minimum wage worker's time or simply the calories used to constantly plug and unplug chargers would greatly exceed the benefit of doing so. **TLDR**: Yes it takes up electricity, but the draw is so ridiculously low that it will actually **costs more** to bother doing it in the long run.",
"The answer is yes and no. Yes, it does \"waste\" some power. But its such a little amount that your family isnt wasting any money. If they are genuinely worried about saving money, invest in a wattmeter and some smart plugs. Basicly shut off power entirely for pligs not in use instead of unplugging everything always.",
"Every charger I’ve ever checked does. More so if it has an LED but even without a light it still consumes a watt or two. You can buy a cheap wattmeter and see for yourself."
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[
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|
h7bnev
|
How does your phone know you’ve rotated the screen?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftrg4ku"
],
"text": [
"It's because of the accelerometer. Here's a link to how they work: [ URL_1 .]( URL_0 .)"
],
"score": [
3
],
"text_urls": [
[
"https://www.livescience.com/40102-accelerometers.html#:~:text=Smartphones%20and%20other%20mobile%20technology,and%20other%20artificial%20body%20parts",
"https://www.livescience.com/40102-accelerometers.html#:\\~:text=Smartphones%20and%20other%20mobile%20technology,and%20other%20artificial%20body%20parts"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7by24
|
- how does the rearview mirror work when tipping it down so you don't get blinded by the car behind you?
|
Was thinking about it on my ride home tonight while being blinded by a truck. Thanks!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftrgwz6"
],
"text": [
"By tilting the mirror you are getting the reflected image off the surface of the glass rather than the silver mirror lining. The glass surface isn’t quite as reflective so you get a diminished intensity of the image."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7cguc
|
How does the scientists or archeologists determine how old things are? Like when they discover something they’ll say it’s 500 y/o or 3000 y/o or older?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftrkztj"
],
"text": [
"Can be done by analyzing certain elements in rocks or organic material. Radioactive elements will decay (lose particles or energy) at a rate that is specific to that element. Scientists refer to this as a half life, meaning how long it will take for half of the material to decay. They can then use this to calculate how old something might be. Carbon-14 has a half-life of approximately 6000 years so if scientists know the relative amount of carbon in a certain object while it is alive, they can compare the amount of carbon left when discovered and use this to calculate how many half lives have passed. If there is half as much carbon then the object is 6000y/o. If there’s a fourth, it’s 12,000 y/o. The problem with this is 6000 years isn’t very long and after a while we don’t have the precision necessary to analyze samples. This is why carbon dating isn’t used for millions of years ago. But there are other elements that can be used that have longer half lives. There’s an isotope (a variation of an element) called potassium-40 (or K-40) that has a half life of over 1 billion years. This element will decay into another element called argon. Scientists can use the relative amount of argon and the half life of potassium (the rate at which potassium decays into argon) to calculate the age of the rock. And finally rock layers on the earth can help with estimating ages. The layers closest to the earths crust are the newest rocks, while the layers closer to the core of the earth are “older”. At this point, age has nothing to do with “creating and destroying” (converting) matter but rather how long has it been since that matter has heated up and turned into magma before cooling into a new rock. Volcanos, earthquakes, and tsunamis are part of the system of recycling old rocks. Volcanos will push new magma up to the earths surface and it will cool. Earthquakes and tsunamis are disturbances in the crust and often result in old rock being pushed down further into the earth. Scientists can look at each of these distinct layers and estimate how long it has been there."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7dth7
|
Why you don't get zapped when touching both terminals of a 12v car battery
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ftrsz9r",
"ftrtidn"
],
"text": [
"It’ll definitely zap a wrench; it’s probably the resistance of your skin. I bet if you lick both fingers and touch it it’d zap the shit out of you. I am not suggesting that you _try_ this, but dry skin is higher resistance than wet skin, for example.",
"If I remember correctly, your body has a resistance of about 100,000 ohms and a wrench has a resistance of about 1 ohm, so that's why a wrench sparks and you don't."
],
"score": [
11,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7evtk
|
Why are the fuel sensors in cars not affected by the jostling around while driving? Wouldn't going up an incline or over bumpy areas make the sensor read the level wrong as the fuel shifts from side to side?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fukks58",
"fukjy57",
"fukklsx",
"fukppqg"
],
"text": [
"Today, the gauge is computer controlled and takes a rolling average of the fuel level. Even back when I started driving in the 90s, fuel level would fluctuate wildly depending on incline. Many cars have baffles in the tank which also help slosh, which minimizes swings in level.",
"The fuel float is generally on an arm, like a toilet tank float, and I think it has damping circuitry so that the needle isn't bouncing around like crazy.",
"Can't provide an answer to why it doesn't do that anymore but it does on older cars. I had a 1990 Toyota camry. Every time I went up the hill, the fuel indicator plummeted towards \"Empty\"",
"In my own car, a 2003 Volvo S80, I can turn the engine off with the fuel light on - go indoors, come back out, turn the engine on and the fuel light is off. With the needle reading higher fuel and the “miles until empty” being higher. The opposite is also true, can go from light off to light on etc. I’ve always just assumed this is normal and that parking at the side of the road (due to the camber) means the surface of the fuel is at an angle relative to the tank."
],
"score": [
14,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7fgpv
|
What exactly makes smartphones screen responsive to touches, swipes, etc?
|
What's that ingredient that helps interface are fingers so that the smartphone screen recognises the input?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fukorm0",
"fukxhr6",
"fukrfou"
],
"text": [
"There are multiple types, but for a common type the simple answer is that your skin conducts a bit of electricity and closes a circuit hidden in the screen. Based on which circuits turn on, it knows where your finger is.",
"Every electric charge causes an electric field. Every electric field displaces charges. Your screen is a plate with equally ditributed charge and a homogeneous electric field. Your fingers also have a charge. Due to the round shape of your fingertip the electric field isn't as dense as somewhere else on your hand. This causes the charge to be pushed into your fingertip. If you come somewhere near your touchscreen, your fingertip's electric field will bend the nice and tidy field of the screen which causes a displacement of charge in it. A displacement of charge is called current. You screen has an array (a tiny grid) of semiconductors that block the current and cause a voltage across the very certain part of that grid. A microcontroller calculates the absolute position of that voltage and triggers the function that lies under that position of the screen (something you can click on). The sensing of the electric field can be really fine-tuned such that you actually have to touch the glass in order to trigger the mechanism. This is why the screens often don't work with gloves unless they tend to continue the field of your finger with certain materials but this is another complex topic.",
"Like other people have said, your \"finger\" is just an electrical conductor that the (capacitive) screen senses. This has some fun side effects. The screen can also detect, for example, a banana peel, and it will still work with a piece of paper in between your finger and the screen."
],
"score": [
70,
16,
6
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7iv22
|
Why is there a loading screen after dying in a video game?
|
So I've notices that in most games, when I die, there is a loading screen before I get back to the game. Even if I respawn very close to the place I died. So why it the loading screen always necessary in this situation as opposed to just moving around?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"ful5qd7",
"ful6b20"
],
"text": [
"The game assets have to get reloaded into the system memory. Playing a level is just an experience for you. But the level is a construct that has rules based in math. It doesn't know what you experience, just records where you save and reloads a level a new when you die in the game.",
"The game needs to reset its state so yo can play again. This takes time, particularly if you respawn in a different place than you died in. Players don't like to wait, so they need to be distracted. The loading screen/movie/... is just there to distract you while the game sets up for a new state."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7jwsz
|
Why is Adobe Flash so insecure?
|
It seems like every other day there is an update for Adobe Flash and it’s security related. Why is this?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fulc0jt",
"fum9q9x",
"fulom3c",
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"text": [
"The \"idea\" of Adobe Flash was to give websites access to functionality that previously only installed programs had. This reduced the need to install a bunch of programs and avoided conflicts from having a bunch of programs installed that you weren't using any more. Alas, this is also exactly what malware wants to do. The Adobe people can't do the obvious things, like restricting dangerous capabilities, because that undoes the purpose of the program. That's why many security people say the only safe thing to do with Flash is not use it.",
"**TL;DR** Adobe Flash was built in a time when they didn't have to worry about making secure code. It got super popular, and when they *did* start worrying about secure code, it was too late to go back and change it. ----- Story time: Back in the days Before Google (BG), personal computing was going through a wild transition. The emergence of CD-ROM technology brought the concept of \"multimedia\" into people's homes. Instead of just text or pictures, applications could now use video, audio and animation to provide information. A plucky little company called \"Macromedia\" capitalized on this by developing a tool called \"Director\", which allowed people to create multimedia applications for distribution on CDs. It proved to be quite popular. Back then, the Internet really wasn't a thing yet--the closest you could get were services like CompuServe, Prodigy and America Online--walled-garden subscription services providing access to curated information over the telephone at per-hour rates. You didn't have to worry about large-scale viruses or whatnot. So Macromedia didn't really worry too much about building Director in a \"secure\" manner. Then, all of a sudden, the World Wide Web became a thing, thanks largely to the Netscape Navigator browser, which for the first time, gave Normal People™ an easy way to use the Internet. The World Wide Web is based around HTML, which at the time, was great for text and pictures but really couldn't do much else. Netscape came up with a solution to that problem: plugins! You could attach little bits of software to the Navigator browser which could be used to play videos, show animations, basically do anything HTML couldn't handle. Macromedia looked at this and thought \"hmm, what if we made a plugin to let web pages have small, fast, scripted animations on them?\" And they did, taking their Director technology and making a plugin called \"Shockwave\", which later got pared down into an animation plugin called \"Shockwave *Flash*\". Shockwave Flash proved amazingly popular. It became a de-facto plugin you simply *had* to install as soon as you got connected to the internet. It became Macromedia's flagship product, taking over from the Shockwave product that it was derived from. So much so that they dropped the \"Shockwave\" name and it just became \"Macromedia Flash.\" Flash's popularity was so great that web developers began relying on it to build entire websites, with increasingly glitzy animations, complex scripting, audio and more. This was still back in the heady late 90s/early 00s, before anyone knew what \"Blaster worm\" was, and what a \"buffer overflow\" was. Responding to web developer demands, Macromedia crammed more and more features into Flash, not really caring about security at all, just performance. And in turn, developers were using it for things it was never designed for. Huge, complicated applications were built entirely in Flash. 3D games, video players, and more. Flash handled it all, but Macromedia never thought about security because they never had to. Then, in 2003, the Blaster worm hit (a worm is malware, but it doesn’t do anything bad to the machines it infects; its only purpose is to “worm” its way from machine to machine). It didn't target Flash, but rather a \"buffer overflow\" vulnerability in Windows. But it wreaked so much havoc all over the world that it forced software developers to start thinking about how to develop their applications more securely in the face of new threats on computers that suddenly had fast, permanent internet connections (broadband had started to become a thing in the early 00s, with cable modems and DSL coming into homes. Before that, home computers largely stayed offline until you connected manually over a phone line using a 56kbps modem). Because of these new malware threats, Microsoft literally spent two years re-writing Windows from top to bottom to better deal with them. So did Netscape, and a host of other companies. But Macromedia didn't. And neither did Adobe (Adobe purchased Macromedia in 2005). Instead, they kept patching Flash to fix new vulnerabilities as they were discovered. Flash was a victim of its own success. Adobe didn't want to re-build it from the ground up, because they were afraid that doing so would break a whole bunch of existing Flash apps. And the fact that it was installed on damn near every internet-connected machine made it an attractive target to attack, and amplified the impact of any exploit. ___ Edit: Holy crap, this blew up. Glad you liked my little history lesson, and thanks for the gold and awards. 😁",
"Flash is the Swiss Army chainsaw of web application. It can do many things, while spewing smoking, making loud noise, and if you do it incorrectly it will cut off your arm. It's difficult to explain at then end of it's life cycle what it can't do (Besides run on mobile). For instance I believe if you are running Flash it can act as a mail server, and thus send SPAM messages, it can save files to your hard disk, it can do practically anything, which makes it impossible to secure correctly.",
"Three simple reasons IMO, and I’m including Acrobat here 1) They are complicated interpreters that do a lot of things, new features are frequently added. 2) Lots of people use them, and hence hackers put time into hacking them. 3) Adobe truly sucks at security. Seriously. Over decades. No improvement. It was once an industry joke, but now nobody bothers to pick on them because it’s just too easy. Like kicking puppies.",
"Making graphics application platform is incredibly hard. On the one hand you want it to be simple to develop. So you should give a nice framework to use high-level concepts like buttons or images. On the other hand you want it to be fast. It means that you take a lot of shortcuts to low-level, highly optimized code, cut some verifications and checks to squeeze additional performance. Then you have very poor browser APIs, with no support for stuff like video codecs and filesystem support (at the moment of Flash creation). And the last problem - if want to allow someone on the internet to access this platform unrestricted, you need to secure it HARD. But that directly contradicts goal 2 (performance) and goal 1 (a lot of features) and goal 3(give access to additional features). And this means that maintaining balance between all these goals is a hard concept, because every performance shortcut you take for additional FPS, every additional OS feature you expose, is a potential security hole. And it all falls on the shoulders of the company that makes graphics tools. And they suddenly need to invest into security of their free product. Modern browsers use incredibly complex multiprocess sandbox in cooperation with OS security features to deliver secure JavaScript experience. And there are only few browsers left that are developed by either trillion-worth technical corporation (Google, Apple, Microsoft cooperate on Chrome/Safari) or by the miracle that is Mozilla.",
"Any one of these answers is basically correct; think of it this way. A modern website is not that frontpage garbage you learned in school way back when. A normal website is an actual application that is running in the browser as if it were an installed program. We use an angular js 'app' for the website I help manage and secure. Instead of returning a 'page' like we learned in school, when you reach for most websites you get a full on application that runs in the browser and the browser itself can allow this application to reach into local resources. An example of this is a lot of banking websites that allow you to scan checks for deposit. That website needs to be able to detect and control the scanner attached to your computer. A normal website can't do that, a 'web app' can. Now, to explain to a 5 year old libraries. Basically very few coders actually pound the keyboard to program every little thing a computer can do. Programming languages can include something called a 'library' which makes life a lot easier. For example, say you want to do 2+2, you code the computer to do that, or you could load cmath library and then write the function as '2+2' and the program will know how to add that and you will get result = 4. Vulnerabilities in software code is often a situation where changing things will cause 2+2 = not 4 or something like that. A developer can't fix that on his/her own, they need an update to the platform to resolve that issue. Adobe flash happens to have a lot of these vulnerabilities and cyber-criminals can take advantage. It isn't just Adobe, it is Java, .NET, etc. Java, as a cyber-security professional, is the bane of my existence.",
"* The web browser is \"just\" an application in your computer. If it wasn’t built for reading your microphone then no website could ever record your microphone. * The above is only true if the browser doesn't have security vulnerabilities. If it does, it may be possible for a web page to \"escape\" the browser and do things on the computer that it wasn't supposed to do. However, if the browser does its best to use only the bare minimum resources and do the absolute minimum, it makes it harder for webpages to gain access to what they shouldn't. It's much easier to access the microphone without the user's permission if the browser supports accessing with permission. If the browser simply doesn't have a feature in no way whatsoever, it's harder for a vulnerability to tap into it. * Flash is like a second application in your computer that happens to interact with the browser. So now if a vulnerability is found in Flash itself, the webpage (via Flash) can do things not originally intended. * Flash had numerous security vulnerabilities because of _when_ it was developed and _how_ it was developed. It's _very hard_ to write safe high-performant code, and since web security wasn't as big of a concern back then, the way Flash was built lead it to be more prone to vulnerabilities. Nowadays we develop applications with many considerations, ranging from sandboxing, to only having the bare minimum privileges to do things and dropping all other privileges, among others. In summary: Flash was a direct line of communication with the operating system, allowing webpages to do what the web browser couldn't. This meant that the _attack surface_ increased and this, coupled with \"not so great\" security practices lead to many exploits and vulnerabilities allowing webpages to use resources they weren't supposed to.",
"Bad programming + Feature creep + Lack of competition for years = software with more holes than Swiss cheese.",
"A lot of replies and comments here are correct, but there's also a lot of misinformation being repeated, so I'd like to contribute my two cents. Flash was originally created as a vector animation player that could be embedded in websites. It actually went through several versions before a scripting language was added at all (version 4 IIRC), and even then it could only jump around the pre-made animation. Shockwave was introduced well after Flash. I believe that it started as an app for making more advanced, stand-alone software for desktops (at least it certainly had this capability, while Flash has always been only for browsers), but a browser plug-in was soon made to be a successor to Flash. However, Flash already had significant momentum by this point, and Macromedia ended up just bringing more and more features over from Shockwave into Flash. Up to and including version 8, it was possible to download the complete Flash file format specification from Macromedia/Adobe. This was a part of their business plan for Flash. Anyway, by reading the specification, you could see all the ins and outs of how ActionScript (Flash's internal scripting language) was supposed to work. And unless something changed massively since then (I would bet that it hasn't), it *should* have been possible to make a Flash player executable that ran relatively securely. I need to talk a bit about how programs actually work, and make a very simplified distinction. Several comments in this thread talk about \"programs\" like a program is a program is a program, and any program can do anything. This is not the case. The comments about Flash programs \"escaping\", or \"getting outside\" the browser are especially jarring. There are many ways to categorise different types of program, but I'm just going to break it down into \"native\" and \"interpreted\". There is more to it than that, but this is ELI5, not an undergrad comp. sci. course. A native program is one which has been created to run on one particular type of hardware (and probably in concert with some firmware or OS). Native programs generally have access to the entire system, at least in theory. In practice, there are a lot of techniques to make native programs ask permission before they do certain things, and to effectively block the program from overriding that permission. While the Flash player itself is a native program, the ActionScript program contained in a Flash animation file is not native, but interpreted. An Interpreted program is one which must be run through another program (usually a native program), in order to execute, rather than executing directly on the hardware. There are plenty of advantages to this, along with some disadvantages, which is why we still have both types of program (although I would argue that the line gets more blurred every day). As an example, JavaScript (ECMAScript) is probably the most popular interpreted language in the world today. Let's imagine that our programs are people working in a kitchen. The native program is a regular person. They can walk around the kitchen at will. They can pick up and attempt to use any implement or piece of equipment. They're free to do anything, which gives them great capabilities, but also makes them potentially very dangerous. So the kitchen designer (hardware architects) put strong safety guards on some of the equipment, and locks on other things. Only the head chef (the OS/firmware) has the keys, because they got there first thing in the morning to open the restaurant (booted before any other software). The interpreted program isn't really even in the kitchen. For Flash, the Flash player executable is there, working in the kitchen. But the ActionScript program contained in a downloaded Flash file is like someone else talking to them over the phone, and asking them to do things. The problem with this situation is that the Flash player is fairly dumb. Flash started off accepting requests like, \"scramble some eggs\" or \"bake a dozen chocolate-chip cookies\", which are harmless enough. But as it developed, the potential commands became less abstract and more detailed, like \"fill a pot with water\" or \"cut the thing on the cutting board into 10 equal segments\". The Flash executable can avoid some problems, like it knows not to put anything but food on the cutting board, or pick up a hot pot with bare hands, but that's not \"common sense\", just a long list of individual rules. When potential requests got to the point of \"turn your wrist 45 degrees\" or \"take two paces to your right\", things started to get ugly. Flash knew to ignore \"block the sink and flood the kitchen\", but it would happily \"boil a pot of pasta\", then \"empty the pot into the sink\", and finally \"turn on the faucet 100%\". That is, until the authors of Flash heard about this latest exploit and released an update that made the Flash executable check the drain in the sink before turning on the faucet. A lot of the time, the head chef (OS/firmware) or their first assistant (anti-virus/anti-malware software) will notice what is happening and stop the Flash executable from wrecking the kitchen or injuring anyone but themselves, but there's only so much you can do to stop a truly malicious attacker without making life hard for others. And sometimes, someone would figure out something like, \"pick up a knife\", \"raise your arm above your head\", \"put your arm straight out in front of you\", \"take one step forward\", \"repeat until the number of other people in the kitchen equals zero\". I wasn't a developer for the Flash software, but I think that the problem with it was, as others in this thread have said, that it was first developed with a somewhat naive outlook. A simple list of \"do not do these\" items was sufficient to stop honest programmers from getting themselves into trouble. But as Flash became more powerful, and more universal (attracting more malicious programmers), it seemed like they just kept adding to that list of individual rules, rather than reworking the software to keep better track of its environment as a whole, which would've been a significant investment of labour for negligible immediate return.",
"Trying to make an ELI5 explanation: Imagine that what you see in your web browser is simply a bunch of delivery packages, these are processed in a secure clean room(sandbox), checked for origin, disinfected, and scanned for bad contents. They are opened carefully and if any do contain malicious material, like a bomb or airborne virus, the blast radius is extremely limited, and sometimes irrelevant. Now with Flash, this ‘sandbox’ secure room is no longer is used, instead you have your 6 year old nephew with a box opener, cutting open every box that arrives and dumping the contents into your living room. He’s doing an okay job of keeping the contents organized but anything and everything will eventually reach your living room floor without any check or validation.",
"Steve Jobs killed Flash by making three dubious claims. 1: it was too slow. 2: it was insecure. 3: it couldn't be fixed. Too slow: what hardware stands still? Certainly Flash was a memory hog on a 2006 Iphone, but was it reasonable to say that it would be a memory hog on a future Iphone with 100 times as much memory? Insecure: everything is insecure. Use a program, expose yourself to risk. The task is to make things secure. Couldn't be fixed: anything can be fixed unless its buried in the hardware (looking at you, Intel). Jobs wanted his app store, and his 40% of every dollar spent on apps. And he got it. Three million free Flash apps died. And Apple just raked in billions. One of the most egregious monopolistic moves in business history. Made Apple around $100 billion. We are not within two decades of the kind of functionality using Javascript and HTML5 that you could do with Flash in 2005. We may never get there because HTML5 and Javascript are such a kludge compared to an integrated program. Source: I once built web systems, then built Flash versions, then went back to web versions. I build animation production line systems for animation studios. HTML5 compared to Flash is like using an etch-a-sketch compared to a full animation studio with a hundred artists. Thanks a lot Steve.",
"This is best understood if we go over the history of web browsers very quickly. it's actually a kind of complicated political struggle between the people who write web browsers and the people who define web standards. This isn't really the question you asked, but I think if you hear the whole thing it will make more sense. Web browsers were initially designed to display basically the same thing as scientific papers. That involves text and a handful of images, but not a lot else. They display their pages based on a special programming language called HTML. (There is a big argument among programmers that HTML isn't \"really\" a programming language, and it's a fun discussion, but for the purposes of this conversation it's fine to say it *is* a programming language and people who want to argue are complicating things.) Later, people wanted to animate their images, or do interesting things as you clicked on parts of pages. But HTML wasn't designed to let people do that. By this time, there were at least two different companies writing web browsers, so to change HTML we had to get both companies to agree to the changes *and* update their web browsers to support it *and* make sure old HTML would still work. This is very slow. So the company Netscape added a new programming language to HTML. This new language was called JavaScript. It added some abilities for HTML change its content on-the-fly or in response to user actions like clicks. At the same time, Microsoft created an alternative called VBScript based on their Visual Basic language. Overall, JavaScript won that battle, but this created another mess: Microsoft's web browser had different JavaScript features from Netscape's. The point was to try to make Microsoft's JavaScript \"better\" than Netscape's so people would make pages that didn't work in Netscape, thus ending the company. Netscape started doing the same thing, and tried to make \"Netscape JavaScript\" better than Microsoft's. This wasn't good for the web. It meant a lot of pages worked on one browser but not the other. Or it meant the people writing the web pages had to work harder to effectively make 2 different versions of their web pages. Both browsers also had a concept of \"plugins\". This allowed you to install software that would integrate with the browser and use *non-standard* HTML to tell the browser it should start that software, download a program, and use the software to run the program. Java Applets are an example of this kind of plugin, Microsoft also created a plugin called ActiveX for their browsers. While these were able to do lots of things HTML and JavaScript couldn't (like streaming video or interacting with your hard disks), they were incompatible. Pages that needed ActiveX would only work in Internet Explorer, and due to politics pages that needed Java Applets worked most consistently in Netscape. (Microsoft famously was sued over this, as they intentionally made Java worse to try and promote ActiveX.) This problem existed because, for a long time, it was the *browser* company's job to write the plugins for other technologies. So Netscape was not allowed to write ActiveX into their browser, and Microsoft could choose to \"accidentally\" make their Java implementation bad. Flash solved this by being a third party. They wrote their plugins instead of making the browser companies do this. That meant Flash was a way to display complicated web content in any browser and have it work consistently. That made it very popular. We didn't care as much about computer security back then. Important features of your OS were accessible and could be modified or manipulated by any program running on your machine. Since Java Applets, ActiveX programs, and even Flash animations were *programs*, that meant they could do very serious things like install viruses or quietly steal your data. Worse: for most people they were configured to automatically run when the page loaded, so you had no chance to stop them. Worse: they could be configured to run invisibly. Worse: since the plugins were configured to download code and run it, people could find ways to \"trick\" the plugin into running dangerous code it would normally prevent. This lasted for years and cost billions of dollars in damage. Browser companies and plugin companies wanted a compromise, but ultimately browser companies decided it wasn't worth it. They changed how plugins work in browsers and made a date (a few years ago) when they'd completely stop allowing \"old\" kinds of plugins to run. In the new style of plugin, instead of the plugin being \"a program that runs with permission to do what it wants on your machine\", it's much more complicated. First, the browser loads a \"sandbox\", which is a special program that acts like a wall between other programs and your computer. A sandbox is a program that runs other programs! The plugin program has to run inside the sandbox, and it can only do what the sandbox allows it to do. So for bad people to attack your computer via plugins, now they have to find a security problem in the plugin **and** a security problem in the sandbox. It's not impossible, but that makes it a lot less likely and thus safer. Meanwhile, HTML and JavaScript caught up. All three of browsers, JavaScript, and HTML started updating with more features faster. Things still dont' work 100% the same across every browser, but we have more sophisticated tools for helping developers handle that today. Things that used to only be possible in Flash can now be done without browser plugins at all. Since that doesn't involve plugins, it's safer."
],
"score": [
6280,
1278,
171,
84,
26,
21,
20,
11,
7,
5,
5,
5
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7jxg5
|
Why is it that windows sometimes slows down when handling specific files?
|
Every now and then I come across a file that just slows my system to a crawl. Something as simple as dragging it from downloads to desktop or even right-clicking it makes it sit there and think for a while before anything happens This isn't even nessesarily large files. It can be small files, too. Usually .exe's, but not exclusively
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuldg20",
"fulcu85"
],
"text": [
"Sometimes the information about each file (meta data) is stored on several different parts of your storage device. For HDDs, it can be slow to move the magnetic head to read all of this data.",
"A file might be exclusively locked by some process, so Windows Explorer has to wait for a lock to be released to access the file. Also your antivirus software might be checking its content."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7kn2y
|
How is a Mirror made?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fulfvtf",
"fulg1lk"
],
"text": [
"Ever played Minecraft? Im joking Mirrors are made by depositing a very thin and smooth layer of silver on a piece of glass. This layer prevents the light from passing by and reflection takes place and we are able to see ourselves in the mirror.",
"I'm pretty sure the majority of mirrors a made by applying a film of aluminum to a plate of glass, either float casting, electro plating, or sputtering. Plastic mirrors can be made using an aluminum foil applique like window tinting."
],
"score": [
6,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7p3dv
|
Why do some electronic devices stay on after being unplugged?
|
Obvioulsy not talking about electronics with batteries, but things like power supplies, battery chargers, and routers sometimes have lights that stay lit for a few seconds after being unplugged.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fumaok7"
],
"text": [
"Capacitors are kind of like a small bucket of water with a big hole on the bottom while batteries are a little like bigger buckets with a hole on the bottom that's only open when needed. So when you unplug your device, there is still water in the bucket but it leaks out of the capacitor within seconds of you unplugging the device."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7p6dh
|
How do game developers keep up with graphics while developing?
|
If a game takes 6 or so years of development, when the game finishes up developing wouldn’t the technology be so outdated that the game looks old when it’s released? How do developers keep the game looking up to date while developing?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fumckfj"
],
"text": [
"What you're saying happens all the time. The most infamous example is Duke Nukem Forever, which was announced in 1997 and came out in 2011, and went through multiple game engines and iterations. But most games take less than 6 years to develop. You can also try to \"future proof\" your game by making it run on cutting edge hardware and allow it to scale up as new hardware comes out."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7pjtc
|
Why does the Snapchat camera look different than the normal camera?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fumf5le"
],
"text": [
"It’s active capturing video, at a high frame rate. It doesn’t know at any second when you are going to press the button and want a still of that exact moment, and won’t have time to charge of the camera cell OR if you are going to press and hold and immediately want to start capturing video frames, so it’s just always capturing high FPS video and immediately discarding it. Other camera apps use what is known as “view finder mode” where its taking a lower res fast image rapidly to show your screen, but when you push, there is a split second pause where it has to charge and capture the full high res image. Humans have been trained to block this out by the shutter sound going off. If you disable that sound you will notice the gap."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7swzu
|
Why we don't have mobile video-calls without an internet connection?
|
If we have the technology to voice-calls years before wireless internet exists, why we don't have video calls without any internet connection too?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fun02go"
],
"text": [
"Voice is quite easy to transmit in analog form over wire, as it's simply vibrations that are turned into electrical signal by a microphone at the beginning end, then amplified to produce sound at the receiving end. This is all analog communications, and is not difficult to do at all. Video on the other hand has a lot move moving parts, literally. It can be sent as an analog signal, but it's much more complicated and requires much more equipment. It was never something that was able to be miniaturized enough to be in everyone's home, or in a small enough device to be carried around. Now, with the internet and miniaturized electronics, it is possible to record digital video and send it quickly enough to have a two way conversation."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7t2lp
|
Electron microscopes give more detail than conventional light microscopes because of electrons’ smaller size/shorter wavelength. Would that same principle hold for smaller particles? How close are we to quark (or whatever) microscopy?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fun18dn"
],
"text": [
"quarks can't be isolated. so to my knowledge we probably wont be able to use them for microscopes. neutrinos would be the only step we could take from where we are. but since neutrinos dont really interact with matter they're kinda hard to use (and create/control) while electrons are much easier to handle."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7u4d5
|
what exactly is an open directory, is using them legal, and how does it work?
|
This concept is totaly new to me and I don't really understand this at all, how come so much that is supposed to be private is public, and is there a possibility that any files or other things belonging to me are public like this without me knowing? And how come this is something there is very little information about to find online, when it seems to be quite a big deal? Thank you.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"funn76f"
],
"text": [
"Well, it really depends what you mean by an \"open directory\". What are you referring to? Can you give some context?"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7uoi1
|
Why is Wifi worse in bathrooms?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"funbo1x"
],
"text": [
"The biggest factor would just be that there are more walls between you and the wifi router. Wifi doesn't go through walls well, like all high frequency electromagnetic radiation. 5ghz wifi is even worse. Adding another to a marginal signal can make it too low. Add that it's possible to have an extra layer of tiles, or denser waterproof gib board and they can have an additional small impact."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h7xruw
|
What’s the difference between film and digital?
|
I always see people talking about how film is superior to digital, and that directors like Tarantino are very opinionated about how much better film is than digital, so I have three questions. What’s the difference between the two, both in terms of how you record with them, and how it looks? Why is digital more widely used when a lot of people seem to prefer film? Why do so many people care, is it just a traditional thing or can you notice a difference?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuo200a",
"funtsb1"
],
"text": [
"Film is light sensitive chemical coated on plastic material. You expose it to light and the chemical reacts and then you use another chemical to set it and turn it into a permanent picture. The finness of the picture is dependent on eveness spread of that chemical on the plastic. Digital exposes a grid of electronic semiconductor cells that are sensitive to light and give off an electric charge when exposed. The onboard computer then processes all of the grid's signals to make a picture. The fineness and quality of the picture depends on those semiconductor cells. Two completely different processes to come up to a picture.",
"Before I start, just know I’m speaking from a photographers POV. Film is an analog process. You have a limited amount of film, which means you have to be selective & accurate with your shots, and you have to actually develop your film to view what you’ve shot. No instant gratification like with digital. For me this makes it better for 3 reasons: 1. I have to slow down. I live my life in the fast lane, and this is the only time in my life I am fully aware of everything I’m doing to produce the best work. 2. I get to be picky. Since with photo film, if I’m shooting a 35mm camera I’ll only get 24 or 36 shots, I HAVE to make each one count, which forces me to evaluate my scene and make each shot different if I want. 3. The only way to see your work is to give it time & development which gives the most satisfaction. I develop & scan my own film, which helps me fully be in touch with the process. It’s a patience & process thing. Now, in terms of visuals, the grain & depth of film is untouchable. Digital can replicate but it’s not as good as the original. I hate digital grain. But there’s something about the grain from the film that gives a more up close & personal interaction. Quentin Tarantino is literally my favorite director, and I think a lot of that has to do with aesthetics. I feel like I could be inside of his films, that’s the kind of worlds he creates. I hope this helps a little!!"
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7yabl
|
Why do companies partner with their competitors?
|
Apple would be the best example of them contracting Samsung for display parts. Why can’t Apple supply their own or go with a non competitor?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"funx1zs",
"fuo296o"
],
"text": [
"Imagine you run a donut shop. You make great donuts and everyone knows it. But you know what goes great with donuts? Coffee. Now, you could spend a lot of time learning the coffee trade, sourcing beans, buying all the equipment, roasting them exactly right, etc. But that would take a lot of time away from making your donuts and would cost a lot of money to boot... And you probably wouldn't make the best coffee. You could also just buy coffee from any number of suppliers, and serve it up with your donuts. Then you get to focus on your donuts, and your customers still get a great cup of coffee... So they keep coming to your shop, because they can get great donuts and coffee together... And you as the donut company get to make money on the donuts and make money on the coffee which you sell at a higher price than what you bought it for.",
"ELI5: Apple is Donut Company, they make donuts with frosting and sprinkles. Samsung is Dessert Company, they make cakes, donuts, and cookies with frosting and sprinkles. Donut Company would rather buy sprinkles from Dessert Company because making sprinkles is too hard to learn and too expensive to buy a machine to do and Dessert's sprinkles are the best. Dessert Company decides to sell their sprinkles because they make too many, selling sprinkles is better than not selling any, and they realize sprinkles isn't the only reason a customer would rather buy Apple's donuts. ELIA: Apple sources OLED screens from Samsung. Samsung is the only producer that makes high enough quality and high enough volume that Apple would accept - there is no one else with good enough quality or quantity. Apple does not have to invest in research and a factory to make a screen which is only one component of their phones - they did the math and makes more sense to buy it. Samsung would rather make sales from a small piece they make then make no sales and have Apple go to a worse competitor - they realize screens are small components and some sales are better than no sales."
],
"score": [
16,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h7yl4d
|
Why do new generation consoles require large downloads before use?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuo0h6n"
],
"text": [
"Game consoles have operating systems, just like computers. As time progresses, the operating system is upgraded and changed. In order to reduce incompatibility issues, crashes, and to ensure parity between yourself and other players, the system requires you to update the operating system before you can use online content or play a game that has certain requirements that need the newer version of the consoles operating system"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h80b7z
|
colorising old photos
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuodpvt",
"fuoe93v",
"fuoi9zt",
"fuoef8h"
],
"text": [
"Having made a career off Photoshop, Photography, Film and Post Production since 1995, i'm going to go with \"yes\"",
"All of the above.. no seriously, when it comes to colorization there is usually very faded traces of color that can be used to start working with After getting that range of color, it’s a matter of what looks natural, what materials things are made of, if there are shadows or imperfections to keep consistent. As I’ve been working with adobe software for 5+ years a lot comes naturally through imagination and other pictures/memories that you have",
"Something the other answers aren't mentioning: history and chemistry Say you're colorising a black and white photo of Union soldiers from 1865. You know their uniforms are supposed to be blue already, but what blue? So you go find an original Union uniform and study it. But what if the dye has changed over the century and a half since it was made? Well you can still learn what the uniform is made of, and figure out what dye was used. Maybe it's even written down somewhere, if it's a uniform, there's almost certainly some documentation or instructions that was produced at the time for the manufacturers. And so now that you know what material was used, and what it was dyed with, you can make some, put it outside in similar lighting as the original photo, take a picture, and you're good to go! Now rinse and repeat with every single thing you see on that picture... What metal was used for that sword? What kind of wood is that rifle stock made from? What would the typical recipes for the bread and stew they're eating be?",
"Yeah, reference images & experience. They're trying to build those 2 things into an AI solution right now which gets pretty good results, where they basically train a neural network with millions of reference color images, then automatically colorize a new given black/white image."
],
"score": [
21,
6,
6,
4
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8261c
|
How can MicroSD cards have different amounts of storage while being the same size?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuojod4",
"fuojjte"
],
"text": [
"What you see is just a plastic casing. The microchips themselves are concealed inside. There's a controller chip which your computer or camera can talk to. Then there are memory chips which actually store the data. If you want to increase the capacity of the SD card you stuff another memory chip inside. If that doesn't fit you use a more expensive type of memory chip which can store more data in the same size package.",
"Why is your car the same size as mine but my car is faster than yours and handles better?"
],
"score": [
7,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h82aj8
|
Why are soundcards still being made and sold as a separate PC component? Do soundcards still provide better audio quality than the built-in audio chips on motherboards?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuojufj",
"fuokigc"
],
"text": [
"They can, yes. Not all D/A converters are created equal, and a quality one (assuming the add on board features a quality one) can make a difference. A motherboard is trying to pack many different things into one price point. A sound card focuses on sound exclusively within their price point so it is reasonable to assume they're probably providing a better D/A converter, and also providing a better post-converter amplifier which can make a **huge** difference. Then we move on to the dedicated ports. In my experience in order to get 5.1 surround you had to sacrifice your microphone port for the built-in version. A sound card can offer more ports to connect things up without sacrificing the mic, may even offer different connection options like XLR (for professional sound settings) or MIDI (for capturing your MIDI-capable keyboard) or what have you.",
"An aftermarket Sound Card usually offers more ports and options for audio inputs and outputs. Such as an an optical plug, RCA, 3.5mm jack, or simply more Surround Sound speakers. Sound engineers usually go aftermarket for refined equalizer controls, sound effects, and the ability to really polish any noises without causing after effects or bleeding from cheap circuits. Lastly, a sound card can help relieve your CPU cycles of sound duties. Which can help improve your games frame rates and certain games will unlock more channels. Providing an enriched experience as you listen to a world that's alive with hundreds of sounds, instead of just a few obvious things."
],
"score": [
8,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h84fdu
|
why MRI machines make so much noise.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuottvp",
"fuou8wa"
],
"text": [
"It's a giant magnet. The magnetic fields produced by the imaging process cause the material to move which moves the air which we hear as noise. Same basic mechanism the makes electrical transformers \"hum\"",
"MRI stands for magnetic resonance imaging. There are large coils of wires that electrical current gets passed through that take images along different axes of the body making the images 3D. The noise is the vibrating of the coils as the electrical current moves through them. [Here's]( URL_0 ) a good link."
],
"score": [
8,
3
],
"text_urls": [
[],
[
"https://blog.cincinnatichildrens.org/radiology/whats-with-all-the-noise"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
h898m9
|
What is GPT3, the language model recently released by OpenAI?
|
[ URL_0 ]( URL_0 ) I know this makes NLP stronger, but what is it and why is it a big deal?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fupixzh"
],
"text": [
"The basics of creating a language model are to take as much written text as you can and feed it through a training model. This model then produces a statistical map of the probability of the likely hood of one word following another, e.g., the phrases the dog is brown and brown is the dog contain the same words, but the dog is brown is statistically more likely. When training a model, you get better results as you feed it more examples of the text. This model uses a vast amount of text to train. It has resulted in a model that is so powerful it can be used to automatically write say fake articles to post to social media or can be used to to produce very intelligent answers when asked to summarize a book or answer questions about a document."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h8bbo0
|
Why are most youtube links like URL_1 id > instead of URL_0 id >
|
Whenever I see a youtube video shared, its almost always, [ URL_3 ]( URL_0 ) , instead of [ URL_1 ](https:// URL_1 ) Is there any particular reason for that?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuq108n",
"fupxqiz"
],
"text": [
"[Have a look at this.]( URL_0 ) > **But why did Google Create URL_1 ?** > > In 2009, Google registered URL_1 as a way of shortening the YouTube URLs. At that time the micro-blogging websites (especially Twitter) were becoming popular. These websites allow people to post messages composed in small number of characters. For example, Twitter allows one post to contain a maximum of 140 characters. Therefore it was important to shorten the YouTube URLs as much as possible so that people can easily share them on popular websites like Twitter. > > By launching URL_1 domain name, Google cut short the URL of a video by 15 characters.",
"URL_4 is a url thst just redirects to URL_1 You can try it out yourself, type ' URL_3 ' in your browser and hit enter. You will be taken to URL_1 These are called link shorteners, Google uses URL_0 facebook uses URL_6 and so on I think pornhub has one too. Xhamster is URL_2 ? Not sure Duckduckgo can also be reached by URL_5 fun fact that url was owned by Google. They gave it to duckduckgo as a gift."
],
"score": [
11,
4
],
"text_urls": [
[
"https://techwelkin.com/difference-youtube-youtu-be",
"YouTu.be"
],
[
"goo.gl",
"youtube.com",
"xh.com",
"youtu.be",
"Youtu.be",
"duck.com",
"f.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
h8cwtm
|
How do SSDs actually wear out / break down on a physical level?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuq65d0"
],
"text": [
"Flash cells in SSDs use floating gate transistors. Normal transistors have a gate over a thin insulator over the channel, loading charge onto the gate let's current flow through the channel Floating gate transistors have that normal gate over an insulator over a \"floating\" gate over an insulator over the channel. To store a bit of data the gate is pulled either way high or way low to force electrons either onto or off of the floating gate, these electrons have to punch through the thin insulator to move Over time the insulators wear out and get little holes in them until the electrons can make it on/off that floating gate easily on their own"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8dvrl
|
What is an image file? How is, for example a png, different when compared to a txt file?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuqbw3o"
],
"text": [
"An image is a grid of pixels, each with a specific color, usually given as three numeric values for red, green and blue. The most basic image file format is called a bitmap, or bmp for short, which simply stores these values consecutively. The file has a short header which includes some data like the image resolution (number of rows in columns in the grid) and the color depth (how many bits of data for each value), followed by the actual values. Bitmaps are notoriously inefficient. A single 20 megapixel image would take up about 60MB (3 bytes for each pixel). Other image formats are compressed. How the compression works is a whole different story and varies depending on the specific format (such a PNG, JPEG and GIF), but generally speaking it removed redundancies and repetitions in the file. In some cases (JPEG) it even slightly reduces the quality of the picture to make it more compressible. Note: there's actually another type of image format called \"vector image\" (such as SVG). A vector image doesn't store pixels, it stores basic shapes such as lines and arcs (and their colors). When displaying the file, the software actually needs to convert it from vector to bitmap. The advantage of this format is that it doesn't have a resolution, so you can freely resize it. This makes it ideal for things like company logos."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8e93b
|
Why do some YouTube videos minimize into a small window when you leave the app on mobile while others just stop?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuqhzfl"
],
"text": [
"I guess you are using an Android device? Some videos are classified as music and their owners don't want YouTube to become a free music player for their content. Because that way you don't watch ads."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8fpgn
|
Why does resetting my router sometimes fix my internet?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuql83a"
],
"text": [
"when you reset your router, it loads the last functioning settings and then creates a new connection to your service provider and your PC/laptop/phone/whatever also creates a new connection to your router. so if (over time) any issues arise in either of those 3 aspects, reseting \"fixes\" them. however if you keep losing the connection it might be worth investigating which of those aspects is the troublemaker. first step I'd take: if you'Re accessing the internet via wifi, try using a cable, just to see if that solves the issue - > there's a problem with your wifi. if it doesn't fix it, then check the logfile of your router, maybe that helps you. if that also doesnt show any signs that something isn't working the way it should - > contact your service provider."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8fubm
|
What is x86-64 and other than the design freedom, what is the advantage of Apple switching to ARM processors?
|
I have a decent understanding of computers, Ive built many custom PC’s, coded arduinos, but I don’t know much about these processors and the technical things behind them.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuqnwh5"
],
"text": [
"ARM processors use a reduced instruction set— basically, they speak a “simpler” language than x86. Besides making it simpler and more efficient to actually send commands to the processor, they can skip physical parts and processing steps that would be needed to interpret/execute more complex instructions. This tends to make ARM CPUs more energy efficient, and more cost effective, than full blown x86 CPUs. And if you have a limited amount of energy or money available, this means ARM offers the best performance possible within those limits. This is why all modern phones use ARM. There are uses where x86 could be better or necessary, but in *most* everyday consumer computing, the expanded capabilities of x86 vs. ARM don’t offer much benefit. The main reason x86 is in wide use is the huge ecosystem of operating systems and software that runs on it, and the number of developers who can *make* software for it, and will continue making software for it in the future. Versions of Windows for ARM were failures because the biggest benefit of Windows is compatibility with a *ton* of software, and that version of Windows gave up that advantage. Apple’s in a good position to change this because they have tons of money to invest, or risk, on this, software compatibility isn’t their biggest advantage in the first place, and the advantages of Macs are largely based on a few professional programs including Apple’s own software (like Final Cut for video editing)... so they can make sure the most popular programs, particularly for professional users, continue to work through the transition."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h8gz9g
|
What is it about the way sails were designed that allowed it to move people across the world, despite wind being a seemingly random and unreliable force?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuqskl5",
"fuqszvj",
"fuqt89v"
],
"text": [
"The force of wind on a sail applies a force through the body of a ship to a keel on the water. Angling the keel allows you to direct your motion with respect to the water. Basically you can go any way except directly into the wind (that requires tacking). edit: Try and visualize where the water is eventually being displaced via the system from the push of the wind. The boat goes in essentially the opposite direction. If you ski visualize how you can go sideways despite gravity pulling you down (imagine the snow spraying out).",
"on local time small scale, wind is unreliable. but in middle of ocean, wind on locations during seasons is reliable. the trade winds literally have a map of location and direction [ URL_1 ]( URL_0 )",
"Across the world, there are [prevailing winds]( URL_0 ). Due to the rotation of the earth, interaction between high and low pressures, and other geographical features, these winds blow in the same direction the majority of the time, for certain amounts of time. A part of being a good sailor was knowing these winds, what direction they blow in, when they blow, how strong they are, etc. A good sailor would also know how to predict winds in unfamiliar location. For example, an onshore breeze is when the land heats up faster than the water, the air rises, and wind from sea comes to replace the risen air. A sailor could plan a passage anticipating these winds in the afternoon."
],
"score": [
5,
3,
3
],
"text_urls": [
[],
[
"https://upload.wikimedia.org/wikipedia/commons/1/18/Map_prevailing_winds_on_earth.png",
"https://upload.wikimedia.org/wikipedia/commons/1/18/Map\\_prevailing\\_winds\\_on\\_earth.png"
],
[
"https://en.wikipedia.org/wiki/Prevailing_winds"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8j4am
|
Why does does unresponsive software sometimes start working normally the second after I try to close it?
|
It’s not loading, I try to close it, it loads normally, then it accepts the close. Why?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fur6c6r",
"fur6f0f",
"fus33vc",
"fus2iw3",
"fus4r21"
],
"text": [
"That depends on why it's being unresponsive. Usually, it's unresponsive because some process is blocked or waiting on a resource that it can't access. When you click the close button, or when you force it to close via the task manager, you tell those processes to stop doing whatever they were doing. Since they're no longer waiting on resources, the program becomes responsive again--but since you clicked close, it closes.",
"When you click the close button, it sends a high priority signal to the software to release any resources it has. One step in this is to immediately terminate whatever the program was attempting to do. Software appears to respond because it gave up whatever job it was trying to accomplish.",
"The software is a kid doing a really hard puzzle that he cant figure out, and is completely focused on it. You are waiting on the kid to finish his puzzle but he just cant, so you tell him to forget the puzzle. He says oh okay, drops the puzzle and gets up to leave.",
"You're clearing a stuck process by killing all processes. Say you have 4 paper balls you're trying drop through a tube into a basket. 1 goes through fine. 2 goes through fine. 3 gets stuck. 4 sits on top of 3. I spray gas on the balls and light them on fire. Ball 3 burns enough to drop through. Ball 4 goes through fine. Sadly, all the balls burn to ash.",
"Sometimes when things get unresponsive I open up task manager as sort of a threat, and just like that shit starts working again. Or maybe it just makes me feel better."
],
"score": [
153,
29,
11,
6,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h8n6ym
|
Why didn't IPv6 replace IPv4 yet ? What's the hold back?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"furtkea",
"furwwix",
"furuyc3",
"furydn1",
"fus821q",
"fuschyj",
"fus2jjk",
"fus8gvb",
"fusad22"
],
"text": [
"One of the biggest issues has been the cost and time of replacing/upgrading customer premise equipment. Older cable modems and DSL modems didn't have support for IPv6 in their software and the hardware had limitations that prevented the manufacturers from just pushing out new firmware that supported ipv6.",
"IPv6 isn't backwards-compatible with IPv4. In other words, you can't send a message from an IPv6 address to an IPv4 address. This has been widely recognized as a colossal failure in the design of IPv6. The plan had been for everyone to use both IPv4 and IPv6, and then slowly turn off IPv4. But many devices never upgraded, and there was no plan to handle that. The other thing that happened is that NAT got really, really good - partly out of necessity. The original thinking was that we'd run out of IPv4 addresses so we'd have to switch to IPv6. But instead we figured out how to let a lot more devices share the same IPv4 address, a technique known as \"Network Address Translation\", or NAT. Back when IPv6 was being designed, NAT had some problems and was considered just a temporary band-aid. But now it's totally normal and robust. The effect is, though, that NAT makes IPv6 less necessary.",
"Chicken and egg situations caused delays for quite a while--ISPs didn't want to spend the money and effort to change everything to v6 capable if the content providers weren't v6 capable, and the content providers didn't want to spend the money and effort if the ISPs weren't giving users v6 addresses. Eventually this logjam broke, both from natural upgrade processes (you may not want to upgrade hardware/software just for IPv6 capability, but if your next hardware upgrade for general capacity includes IPv6 support, why not), and from the growth of mobile internet, which was taking off right around the time IPv4 was getting scarce. You still don't see it much from wired internet because there's not a real need for it. Converting from IPv4 to IPv6 is not really something that provides an obvious benefit (certainly removing NAT from the home router has both pros and cons), and while we're out of address allocations at the highest level, I don't think ISP/household level address space is at an immediate risk.",
"Ugh i totally forgot subnetting with ipv6. Just the thought of memorizing it again makes me hope ipv4 sticks around for a lot longer lol",
"People seem to have a lot of technical explanations, but i think the real answer is much simpler. Implementing IPv6 is work for ISPs that don't bring in any (new) money. Refusing to provide IPv6 while we've run out of IPv4, means the addresses already owned by (mostly western world) ISPs become a valuable asset which will just increase in value as long as they continue to resist implementing IPv6. Combine this with customers being too clueless to demand IPv6. In other words, implementing IPv6 is counterproductive for commercial ISPs - atleast from a commercial aspect (as long as customers allows them to get away with it).",
"Network Engineer here. IPv6 didn't replace IPv4 because IPv6 was designed to include it. It's actually already here, and all around us. Most computers running today actually *can* support IPv6, and depending on your configuration, you can reach IPv6 networks from over an IPv4 router or firewall. The network I run for work is almost entirely IPv4, but I'm able to route traffic to IPv6 addresses because they follow my default route to an IPv6 capable router. All that's necessary is the devices which apply network address translation need to be IPv6 aware, so that they handle the substitution correctly. This typically means firewalls, load-balancers, and proxy-servers. So, why do I still run IPv4 on my network? It's easier, and I don't get paid extra money for building more complicated networks or working harder to provide solutions to my business.",
"IPv6 was created to solve a problem of not enough ip addresses. NAT allows companies to use the same IPv4 address for multiple devices thus aleviating the stress and urgency for more addresses. It takes time and money to swap everything over to IPv6 so many places don't want to do it unless its necessary. It will happen eventually and many companies already run both IPV4 and IPV6. Cutting over to IPV6 completely would mean legacy devices that don't support IPV6 will no longer work. It has to happen eventually.",
"Shortest answer, IPv6 is complicated and because of other solutions like NAT we haven't needed to switch badly enough for people to bother.",
"Heard recently on URL_0 podcast: - IPv6 assumes all devices in LAN are directly public, which is a very new paradigm. Needs separate real firewall with zones etc. - IPv4 and IPv6 firewall/security will be completely separate, have do it right twice. - NAT with IPv4 works okay. - IPv6 won't replace IPv4, so IPv6 will be an addition, and thus has to be justified on its own."
],
"score": [
44,
35,
16,
10,
7,
5,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://2.5admins.com/2-5-admins-05/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8ouf4
|
In what context is code written by hand, on paper, ever useful ? Can computers even execute that sort of code ?
|
Take for example the picture of Margaret Hamilton standing next to a tower of books, the code she and her team wrote that took the first men to the moon. How was that pile of code executed on the computers of the Apollo spacecraft ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fus2oja",
"fut61ba"
],
"text": [
"These are just printouts of the code. [Here's an image gallery]( URL_0 ) showing what they look like (see the last two photos). You can even find the actual code [here]( URL_1 ). The printouts are useful for stuff like archiving and debugging purposes (it's not like everyone had a PC they can use to look at the code).",
"Until about the 1970s, you'd write code by hand and then someone would enter it into a computer using punch cards. You didn't have computers with editors. Generally, a programmer would write the program on a coding sheet, basically graph paper that was 80 columns wide, to match the width of a punch card. (This is why programmers commonly use 80-column lines now.) The programmer would give a stack of coding sheets to a keypunch operator, who would punch the code onto cards using a keypunch, a machine with a keyboard sort of like a typewriter. You'd then take boxes of punch cards and give them to the computer operator, who would run them through a mainframe computer, which would compile the program. The resulting machine code might be punched on more cards, or stored on magnetic tape. Finally, you could run your program. Getting back to the famous Margaret Hamilton picture. Each binder held the source code for the software on an Apollo Guidance Computer. (I've looked through some of these binders.) The code is written in a combination of assembly code and an interpreted mathematical language (kind of like a better assembly code with trig and vector operations). This code was assembled on a large Honeywell 1800 mainframe through a complex program. (It was kind of a primitive github, tracking changes to the program since for the space mission it was important to know what was being changed.) The results of the Apollo code were punched on a paper tape. This was fed into a machine to generate a core rope. The core rope physically stored the machine code by putting a wire through a tiny metal ring for a 1, or around the metal ring for a 0. This was a primitive ROM for storing the program in the Apollo Guidance Computer. The core rope was generated by a combination of women manually threading wires through the cores and a machine (controlled by the paper tape) that positioned the right core to get threaded. I worked on the recent Apollo Guidance Computer restoration ([videos]( URL_0 )), so I can answer questions."
],
"score": [
7,
7
],
"text_urls": [
[
"https://imgur.com/gallery/Dp23C",
"https://github.com/chrislgarry/Apollo-11"
],
[
"https://www.youtube.com/watch?v=2KSahAoOLdU"
]
]
}
|
[
"url"
] |
[
"url"
] |
h8pj2a
|
How do the electronics behind automatic answering machines with menus work when you input numbers on your phone to get to the right person?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fus6057"
],
"text": [
"Every phone uses the [Touch-Tone]( URL_0 ) standard. When you press a number, your phone makes a specific sound (a combination of two tones, actually - you can see the list [here]( URL_0 #Keypad)). The automatic software simply analyzes the tone so it knows what number you pressed."
],
"score": [
6
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling",
"https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling#Keypad"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8sd2j
|
How does a phone reboot work? How does it know to turn itself back on after it turns off?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuvdkqb",
"fusk9xo"
],
"text": [
"* Computers work by feeding commands into a processor. * When you run an app on your phone, the phone loads the list of commands that make up the app into memory, and then starts feeding them, in order, to the processor. * When you boot up your phone, it has a built in set of commands that tell it do things like check out how much memory it has, and what kind of storage it has. * One of those commands checks the storage for an operating system. * When you \"reboot\" a phone, it doesn't shut off, it just loads those built-in commands from the very start of the list again, just like when you first boot the phone up.",
"Just like a computer. It is a separate process from completely powering off, that keeps the cpu powered and then just brings it back up."
],
"score": [
8,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8t04b
|
How do headphones generate a feeling of "in front" and "behind" despite having only 2 outputs?
|
I recently listened to an 8D audio and I wondered how it's possible, that we hear wether it's in front or behind us. Like by having two speakers right and left.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fusneae",
"fuvcrb0"
],
"text": [
"I think what it boils down to: The shape of your ears will add a distinct \"sound\" depending on where a tone is coming from. Some frequencies will be dampened and some will be louder when the sound is coming from a specific direction. One way to record super-realistic stereo sound is to use a literal [model head]( URL_0 ) with microphones where the ears would be to capture all those effects, then your headphones simply reproduce those changed sounds directly into your ear. It's also possible and much cheaper to computer-generate a basic version of that though.",
"* Sound is a pressure wave that moves through something. * Most of the time it moves through air molecules. * But it also moves through: * Walls * floors * ceilings * humans * water * etc * As the waves interact with things, they slow down. * But not all the frequencies that make up the wave slow down the same amount. * So depending on the size, shape, and material make-up of the things the waves hit, the sound is altered. * This is where the shape of your ears come into play. * They slightly alter the waves that make it into your ear canal. * The waves that approach your ear from the front are altered a slightly different way than the waves that approach your ears from the sides, or from the back. * As a human grows and learns, its brain gets very good at decoding those slight differences to figure out where a sound is coming from. * This, by the way, is why sometimes your brain can be fooled. * Clever sound designers can mimic these alterations. * So they can send two different sounds into your ears from the exact same angle (from the headphones), and ***trick*** your brain into thinking they are coming from different directions."
],
"score": [
6,
3
],
"text_urls": [
[
"https://www.gear4music.at/de/Recording-and-Computer/Neumann-KU-100-Dummy-Head-with-Binaural-Stereo-Microphone/1BGY"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h8wjhj
|
How do they measure the area of a land (e.g., city or country) which has a very irregular shape with houndres of edges?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fut82e6"
],
"text": [
"Historically they used to estimate and didn’t measure exactly, for example a large bit of land may have an uneven edge but if you can draw a line so roughly the land you exclude is equal to the area included with no land then this is a good estimate. Nowadays, satellites can see everything and take an image which, when taking into account the curvature of earth, can be used to calculate the area much more precisely."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8wthk
|
If a toothpaste says it will whiten your teeth one shade in two weeks, does that mean it really takes two weeks, or could you brush your teeth 28 times and it'll whiten them?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"futcc2s",
"futa3ji",
"futc0x2",
"futcw44",
"futc6xb"
],
"text": [
"Over the counter whitening toothpastes use an abrasive agent to make your teeth look whiter. This works by removing a small layer of stained enamel from your teeth, exposing fresh unstained enamel. The idea is to use the toothpaste twice per day over 28 days to slowly remove the stained enamel. Overuse (say 28 times rapidly) could cause excess loss of enamel, leading to sensitivity and in extreme cases the need for fillings to repair areas where too much enamel has been removed. Excess loss could also be caused by using such toothpastes too soon after eating (less than an hour), especially you've eaten or drank anything acidic such as orange juice. Source: I am a dentist.",
"It’s time. Teeth whitening is basically bleaching, so the approach is to put a low power bleaching agent on and give it time to do it’s thing and repeat.",
"Tooth Whitening pastes use time, abrasives, and maybe some chemicals like peroxide to break down the stains. Doing it too much in a short amount of time may (this is not conclusive) damage enamel and is thus not recommended.",
"Add on Q; I’ve been brushing my teeth twice a day for ages so why aren’t my teeth sparkling white?",
"As was said in the comments. It has some bleach in it. It's not recommended to brush your teeth with paste more than twice daily though. There are multiple abrasive materials in paste and brushing a ton per day can damage your enamel"
],
"score": [
4525,
298,
119,
15,
12
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h8y4pq
|
How come a 4 minute .mp4 taken from my phone is the same size as a 2 hour movie?
|
I am an avid torrenter and most of the movies on my PC are about 2 GB. I just took a 4 minute video on my Pixel 4 and was astonished to see that it's also 2GB! What kind of compression magic goes on that I'm able to get a 1080i movie with the *same file type* to take up 3% as a phone video? It's not like my phone video is 30x the quality of 1080i...
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"futlgzq"
],
"text": [
"Good video compression takes time... Each frame is compares to the next one and the previous one, a lot of optimizations are done, and the filesize is small. With a mobile phone, you have to do all that in realtime, and don't even have the next frame to compare the current one with, because it hasn't been captured yet. Even with modern computers, optimally compressibg a minute of video often takes more than a minute (even with a really good cpu and a graphica card). So, with a phone and a relatively weak cpu (compared to PC ones) , you could sacrifice quality, to compress video more, or just waste some more space, keep the quality high, and have the user delete/reencode videos later."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h8zn2b
|
If i send a text message to someone connected to the same Wi-Fi network as me will the text message leave the network?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"futqx0b"
],
"text": [
"It won't just go through your wifi. If it's an SMS then it doesn't use wifi at all, it uses your cellular connection. If it's an app such as Whatsapp, the message goes through the app's servers first."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
h91qjy
|
Servers
|
What is a server? What role does it play in hosting a website? Where are they based - is it physical or virtual?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuu6cjy"
],
"text": [
"Server is, in short, a program that can listen to network traffic and send apropriate content to the user that requested it. In case of a website, it will serve website's content - webpage itself, its graphics, data, etc, that your browser will then use to render the webpage on your screen. Servers can be both physical - aka the machine that runs the program, with a single purpose, and virtual, i.e. a web server program that serves many hundred websites, from one device, under multuple web adresses leading to the same physical network card. Sometimes, for very large webpages ot apps (like gmail, or banking systems) you will have several tens or hundred machines working together for that single web address, usually spread out geographically over the world, and behind apropriate load balancing systems, which then i turn listen to, and reroute, actual user traffic. They can be based in a large datacenter somewherr, or in your bedroom - you just have to install apropriate software on your computer (and have network connection accessible from the outside, some internet providers do block such traffic to an extent to avoid having too much of it to deal with for example), and get an address for it for a few dollars, or for free for that matter."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
h93uc1
|
What is deep learning?
|
Can someone please answer this. It would be really helpful for me!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuuxzzy",
"fuuodao",
"fuv0jsn"
],
"text": [
"Neural networks are classified by the number of layers they have. The more layers they have, the more complicated a thing they can do, but they also become harder to train. When the network contains many layers, we begin to call it “deep.” The distinction is made because until perhaps 2014, networks with many layers were difficult or impossible to train. In recent years, the term has lost its character and importance, and is now generally applied when someone working in neural networks wants to make themselves sound important.",
"If I show you an apple, you'll instantly recognize it. What if you want a computer to do the same? How will you tell a computer what's an apple? You could think of an apple as something which has a specific shape and is red in color. So instead of telling your computer to recognize an apple you tell it to look for a particular shape that's red in color. If a computer finds something like that in an image, it'll know it's an apple. The process by which a computer \"learns\" what's an apple is known constitutes \"Deep Learning\". You can not only teach a computer how to recognize an apple but also do all sorts of cool things like predicting the next word in a sentence, auto-correcting, grammar checks, playing chess, driving a car, etc.",
"There are three levels of artificial intelligence, based on how they handle two problems: * How to turn raw data into a format computers can work with easily (feature extraction) * How to go from that format to an answer to a high-level problem (modelling) Say you have pictures of individual vegetables and you want a computer to tell you what is in each image. The oldest and simplest approach is to hand-code rules that will handle both problems. For example, for each picture, you could have yes/no values that answer whether the most common colour is green, whether a circular shape can be found, etc., termed *features*. These must be *simple* queries, because you want the computer to be able to answer them without human input. Next, you have *more* rules to process the output of the previous step. If an object is both green and circular, it's a pea; if it's not green but circular, it's a tomato, and so on. Clearly, it's time-consuming (not to mention influenced by individual bias) for humans to manually come up with appropriate rules. The next development was to allow the computer to determine what rules were appropriate for the second step. There are multiple mathematical techniques to do so, but briefly speaking, the idea is to associate features and results, just as humans do. For example, if you have many images, on average it is likely that the ones with green and round objects are of peas, and a computer can recognise that through simply calculating ratios. Deep learning takes this a step further, by *also* deriving the rules used for the first step: transforming something that is high-level and ordinarily only comprehensible by humans, such as images or natural language, into features. In general, what these features mean is not easily understood by human beings, because they're simply what the computer \"thinks\" best represents the characteristics of the input, *from a mathematical perspective*. Another way to look at it is that from the perspective of deep learning, feature extraction and modelling happen *together*. In other words, deep learning uses mathematics to perform feature extraction in a way that will make it most able to answer the question at hand; in this case, identifying vegetables."
],
"score": [
6,
6,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
h96o50
|
Video game's difficulty upper limit
|
How do game developers know the upper limit of difficulty for their game? What I means is that how do game developers know not to make the game so difficult that it is impossible for players to defeat the game. How do they test out the difficulty?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuv18xx",
"fuv13e6",
"fuvkf8s"
],
"text": [
"Simple: they beat it themselves. For example. With Castlevania (a game known for being REALLY hard) the person programming a boss had to be able to beat that boss without taking *any* damage. If they couldn't do that reliably then the boss was too hard. A good rule of thumb for a developer is what then you think the game is way too easy, it's probably just right. And when you think it's just right it's probably way too hard. Also, for at least anything but the most indie of projects, they are going to have a lot of playtesting where people give input on the difficulty.",
"Play testers are paid to play the game, presumably at different difficulty levels, and report how hard it was (among other things). Besides, many times developers create a highest difficulty level that is practically impossible and are them surprised that some players actually manage to beat it.",
"Play it. If it \"feels\" too hard, or there are particular things you can't do, then you change the game and make it easier. At some point, have a limited group of other people play it. You could literally hire a bunch of people to sit in cubicles, play your video game 8 hours a day, and report any problems or issues. Although these days you can often find people on the Internet who will do it for free, or even pay you to have \"early access.\" People who have never played your game before are usually really informative. So it's good to have a supply of \"fresh\" testers, since the devs and the people who get paid to play your game 40 hours a week for months will get pretty good at it, and might not accurately be able to judge difficulty."
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|
[
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[
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h97jwu
|
How video game cutscenes change the look of the character during the cutscene according to characters custom appearance?
|
For example, in Dark Souls in the cut scenes you will see the character and it will look like your character with the same armor, physique, etc. but I can't understand how they change the character in the cutscene to look like yours. Wouldn't they need to make a cutscene for every possible armor and character combination?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuv3y6g"
],
"text": [
"Those kind of scenes are in-engine/game scenes, as opposed to being pre-rendered. It moves the camera and controls your or other characters to make the scene play out. They have other kinds of tricks and stuff they can use, but that’s the main part. So that allows them to use whatever character model you have at the time."
],
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|
[
"url"
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[
"url"
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h97syf
|
Why are brailles dots instead of our letters?
|
Technology
|
explainlikeimfive
|
{
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"fuv77uo",
"fuvd4dz"
],
"text": [
"Raised letters have actually been used in the past, but they have been clearly superseded by Braille. Braille is much faster to read, mostly thanks to zero ambiguity and unified shape of letters. (Imagine telling apart letters *written in an unknown font* by touch.) It doesn't need as much space, so you can fit more text onto a page. Braille is much much faster and easier to write: punching the dots into paper is mechanically simple so it's cheaper and easier to produce the necessary hardware. In a pinch, you can write something short with a simple stylus. (You have zero chance of producing legible raised letters by hand.) Finally, Braille translates well into the modern world -- e.g., Braille displays are a thing that was also made possible quite early thanks to the simple nature of the alphabet.",
"Latin letters are generally terrible for telling apart by touch, as several letters aren't terribly distinct from others. Go find an engraved or embossed sign or plaque somewhere and try telling letters apart by touch. You're likely going to have trouble telling the difference between letters like: * O and Q and 0 (hell, 0 and O have a tendency to trip up perfectly sighted people, hence the use of slashed or dotted zeros) * l and I and | in sans-serif fonts. * i and j, which can also be confused for the above in tittleless fonts. * o and a in some fonts"
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[
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|
h98tzm
|
If I enter a password wrong thrice, the system locks me out. How are hackers able to attempt millions of combinations of passwords without the system locking them out?
|
Edit: Thank you everyone who’s taken out time to explain it to me. I’ve learnt so much. Appreciate it. Yes, I do use ‘thrice’ in my conversation whenever required. I’m glad it amused so many of you.
|
Technology
|
explainlikeimfive
|
{
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"* Modern passwords work by a process called \"hashing\". * Hashing basically means: * you take some input, like the characters someone enters for a password, and you shove it through a machine. * That machine then spits out some new string of characters that doesn't seem like it has anything to do with what was shoved in to start with. * But the trick is that it does have some sort of connection. * The only way to get that specific output is to feed in that specific input. * So when you sign up an account with a website, they take the password you made up, shove it through their hash-machine and then store the output. * So even if they get hacked, the hacker will only get the hash, not the password. * But when you go back to the website and enter in your password their hash-machine will spit out the correct \"hash\" and since it matches with the one linked to your user name, they let you in. * However, if a hacker was able to steal a complete list of all the hashed passwords for a site, they could build their own hash-machine and just start trying every possible combination of inputs to see if one of them spits out a hash that was in the list. * This would allow them to make as many attempts as they want without running into the rate limit on the website. * This is typically not easy to do though. * So most hackers actually just try to trick you into giving them your password. * Like sending you a link on Facebook that looks like it leads to a login-page when really it's a fake website that just copies whatever you type in the password box. * EDIT: Updated to more directly answer OP's question.",
"Many answers here are tackling how attackers use leaks and phishing to accomplish this, but I do want to highlight one frequently used brute force method: There is a very common attack vector called “password spraying”, which essentially uses a set of common passwords (iloveyou, password123) generic to everyone and/or personalised ones (firstname123, email alias, phone number, etc.) to see what accounts they could get into. The key is that you can set up password attempt limiting in two ways - * absolute attempts: no matter who is trying to sign into an account, lock it up after x attempts. This means that if you tried to sign into your account with a wrong password from your phone twice, then from your laptop once, it would lock you out of your account. Many high security financial apps have this. * relative attempts: they lock your device out, but not the whole account. Websites use information about your device (e.g. from your cookie), session, IP, etc. and just lock you out from that attempt. While this works against manual hack attempts, like your boyfriend trying to log into your messenger account, it doesn’t protect much against automated hackers. All a hacker has to do is reset their proxy to a new location, clear their cookies (both of which can be automated in a matter of milliseconds), and try another set of passwords as part of a new attempt. Most social media accounts that are optimised for access rather than security use versions of this, with varying levels strictness of how they define a new login attempt. But in any case - use good, strong passwords. And don’t use the same one everywhere - some websites are incredibly easy to crack or reverse engineer so your security online becomes dependent on the weakest link. **edit: to add a bit more context on spraying, these attackers don’t typically try a bunch of passwords on a few accounts. Instead they try a limited set of common passwords on a bunch of accounts. It’s incredibly easy to buy dumps of registered email addresses - I’d bet that at least 3% of them have a super common password.",
"They're not doing it that way. If they're attempting password combinations, then they already have a copy of the password database file, with encoded (hashed) passwords. Hashing algorithms are no particular secret, so what they;re doing is taking a word, hashing it, and comparing to the database to see if they have any matches.",
"This method of trying millions of password combination (known as brute force) is NOT widely used. It is not an efficient (if practical) way of getting login credentials. It is used in unlocking zip files where you aren't locked out. You can always use Proxy, VPNs but that will slow things and impractical in lot of cases. AFAIK Most used method of hacking social media and related things is Phising and Social Engineering. Edit: grammar fixes",
"The answers given so far all seem to be correct, but appear to answer a different question than the one asked. You are 100% correct that if attackers use the same website/system to attempt a login, then they will also get locked out too. Consider this flowchart/steps needed to login 1. Type details into your web browser and click submit 2. The web server computer receives this data and decides whether to continue or not (e.g. auto reject if you've tried too many times) 3. The web server computer then communicates with the database server computer to see if the data you submitted matches the data they have stored (I.e. username/password/email address/whatever) 4. The database replies with the relevant information/data for the web server to use 5. The web server computer then responds to the user with the relevant response (e.g. \"no\" if it doesn't match up) What if you could trick step #2 into always allowing you through, or what if you could skip around steps 1+2+5 and have the database respond directly to you? The first way around this is to figure out how they determine \"repeated attempts to login\" (i.e. step 2) - e.g. they might be counting the number of attempts coming from a specific computer/IP address etc, in which case they will just use lots of different computer to get more attempts (e.g. a network of remotely/robotically controlled computers - a botnet). This doesn't work if they're counting the number of attempts to login to a specific account though as it won't matter WHERE the attempt came from, just that an attempt was made. Another way around it is to bypass the checks/counting. Wherever the counting is taking place, if you can avoid that then you no longer have a limit on the number of attempts you're making. One option might be to find some way to reset the counter, but in practice this typically means getting direct access to the database and running your attacks against that. When you have direct access to the database (either the live one with protections bypassed, or a local copy of it that you downloaded) then you have as many attempts as you want/need. Other answers go into substantial detail about what is normally stored within the database and how that is attacked, but that is mostly irrelevant when considering the number of attempts made.",
"It depends on what is happening: - If you try to login to a website, then they will into the same problem. - If they have stolen the encrypted passwords, then they are not any longer under the restrictions of the site which performs the authentication. As such, two different scenarios, two different limitations.",
"Simply put. If the system is secure enough, they can't. However sometimes things get overlooked. A login screen might have the protection but maybe the api does not.",
"I saw a bunch of answers that didn't answer your question. If a site locks you out, they either have to limit their request per minute low enough to not get locked out (which is ridiculous, and no one ever does) OR They found your credentials on a dump and are trying it everywhere. As an example, let's say target gets hacked and someone gets their user database (which has emails+passwords). Someone then sells these credential dumps on the black market. Eventually, they end up in public credential dumps (such as ones the 'haveibeenpwned' website uses). Either way, 'hackers' will take these and blast them to every site they can think of to try to get in. tl;dr - They don't try millions of combinations, your user+pass probably got leaked by a garbage website. That or the site got hacked some other way. P.S. Really, really old or poorly coded websites/applications won't do lock outs, in which case your question doesn't apply. P.P.S. I simplified this, and didn't elaborate on the examples - which could be clarified to be more accurate. The general idea should help the OP understand what happens.",
"In the olden days where brute-forcing actually worked, you'd just pretend you're a different person. You'd have a program which basically worked like this: * You gave it a huge list of passwords to try * You gave it a huge list of proxy servers to use. Think of a proxy server as another person tasked with giving the site the password attempt * You told the program \"Go tell this site that my password is: xxxxxx, if it fails try another password from the list, if it fails try another, if it fails a 3rd time, use a different proxy (ie tell another person to try three more passwords)\" So the program would pretend to be a different machine, connect, try 3 different passwords, then switch to pretending to be another machine, try 3 more and so on and so forth. So what the site saw was different people trying 3 different passwords each.",
"Yeah none of these are a clear answer. They use what's called a proxy, it's basically your connection routed to another and the new connection has a different identity (ip). This is what they use to bypass the multiple login attempts because when you want to log into your account from a new computer the service won't just say: nah I've never seen you before, they're like: ok 3 tries and then I'm done with you. Edit: Note that services especially popular ones will have limits in place to try and keep you protected, most places will send you a password reset and lock your account after so many tries so this method isnt always the best but nothing is stopping you from hitting 100 different services with the same email.",
"If you enter in a password wrong thrice, it only knows the person logging in from your IP address failed three times. If you log on from a different IP address, it may let you try three more times since it doesn't know you're the same person. Hackers typically have access to many thousands or millions of IP addresses to try a password on. The service you're logging into may see the high number of people who are trying to access your user name and decide to block you out entirely to prevent further guesses on your password, but that gives hackers the ability to lock you out of your account at will. Security often comes down to choices about how secure you want to be vs how easy do you want to make using the service.",
"There are a few different ways. In some cases the number of wrong guesses reset after a certain amount of time. If the number of bad guesses resets after 20 minutes just do 1 guess every nine minutes. Another favorite is to take the top two most common passwords that conform to the site’s password policy and try it against every username you can find. Someone is likely to be lazy and will use a bad password.",
"Software is usually made of layers. The layer a user sees has all sorts of protections to prevent users from trying a bunch of combinations, which would make password checking pointless. Now, a layer or two below that, passwords are stored in a database. When hackers pierce a system go looking for that database. Or the one with credit card numbers. Usually, as mentioned by other comments, passwords and other sensitive info is stored all scrambled and unusable. But the info can be transferred to another system where the cracking can be performed without slowdowns. As mentioned by other comments historically passwords are taken using more common, human methods, such as email and phone fraud or by impersonation. Think of heists vs small theft for a general idea.",
"They can't. This is TV magic. Trying millions of combinations is called a bruteforce attack and it is an extremely weak. For one, it can't be used over networks, exactly because systems lock you out. Using proxies to overcome this is stupid and trivial to defend against. Proxies also cost money. Where do you have 2 billion IPs to crack a password? Second, even if you have the system with you on your machine and it can't lock you out. Very basic security means it is literally impossible to try enough numbers to guess it, even if you had all computing power that exists on Earth before the death of the universe. It's trivial to make impossible to guess passwords. Guessing doesn't work. What they do is find where the password is stored. Maybe in someone's brain, in a file, on a piece of paper, if this password is being then it's stored somewhere. You just have to find it.",
"They aren't trying to unlock a specific account. They try a specific password for millions of accounts and some of them will match and it'll be unlocked.",
"Haven’t seen many accurate answers, and none that are accurate and ELI5. There is a guessing game at a carnival where You need to guess a number between 0 and 100,000,000. There is only 1 correct answer. You get 3 tries to guess correctly, then you lose. Playing the game honestly is very, very hard - so you cheat. You steal a copy of the game and take it home. You play the game at home and start guessing. Maybe you ask some friends to help you guess to make it go faster. After a lot of time and many guesses, someone eventually guesses the right number. Now that you have the answer, you go back to the carnival and play the game. Amazingly, your “first” guess is the right answer! You win the game and everyone thinks you’re incredibly smart or incredibly lucky. In reality, you are a very hard working cheater. That’s like 90% of computer hacking.",
"I feel like a lot of attempts to answer are getting close but not really. First of all, password crackers are not trying millions of combinations on your login on the login site. So if your Gmail is getting hacked, it's not because they tried a million combinations on [ URL_1 ]( URL_0 ). Here's a few key points to quickly answer what you're looking for: * Brute force attacks are likely done offline. This can be accomplished by hacking a locally stored password file/hash where you're only limited by the speed of your hardware. There's no online server validation checks, no bandwidth limitations, and no retry limitations from the server. * A lot of accounts getting hacked are the result of password file leaks from websites/servers. * Password reuse means that if someone cracks your Yahoo password, they likely also got your Gmail, Reddit, Twitter, etc password. Detailed explanation w/ example: 1. Major website gets hacked like Yahoo, LinkedIn, DropBox, Adobe. 2. Password file gets downloaded with millions of credentials 3. John Doe's email/login is in there, and chooses to use a crappy password like P@$$w0rd1 which happens to check some of the basic boxes of capital letters, lower case letters, symbols, numbers. 4. Basic primer about passwords is that they're stored as hashes. So John Doe's password is never stored in plaintext (unless they're REALLY REALLY bad at security), but generally using a common hash like MD5 or SHA1. Essentially what's stored is MD5(\"P@$$w0rd1\") or SHA1(\"P@$$w0rd1\"). In the case of SHA1, that hash is \"3A3346168E86EF3EE999EE1E4F3EE3D87CAFF938\" 5. Hacker runs a brute force app which tries combinations. Because the password file is already downloaded, they can do this all offline. They usually can figure out what hashing algorithm is used because a lot of times that is documented. They basically run a dictionary through by trying SHA1 combinations of all those words. They can try common passwords too and basic iterations like \"P@$$w0rd1.\" A modern GPU can run hundreds of millions if not [billions]( URL_2 ) of guesses per second. It ties all these combinations until it finds a password that matches the stored hash. Hacker has found John's password, and now records P@$$w0rd1. 6. Hacker now tries this [johndoe@ URL_1 ](mailto:johndoe@ URL_1 ) / P@$$w0rd1 combination on a bunch of popular sites. Maybe John Doe isn't that bad at password reuse, so the hacker breaks into his Twitter, Reddit but not his Banking account. Hacker can't get into Gmail, but gets into his Yahoo account which happens to be his recovery account for Gmail. With some basic password recovery/reset, they get into the Gmail, get into the rest of his accounts by using \"forgot password\" at every site where P@$$w0rd1 fails to work. 7. John is now totally screwed as the hacker wreaks havoc."
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}
|
[
"url"
] |
[
"url"
] |
h9b79j
|
How does torrents work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuvpauv"
],
"text": [
"basically the bittorrent protocol allows everyone that loads a particular torrent file to discover each other. and once they discovered each other, they can figure out who has what data for the torrent and then they figure out how to send data directly to each other."
],
"score": [
3
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
h9c2z6
|
Why do some microphones pick up their own speaker sounds, and others don't in laptops?
|
After having used multiple laptops and speakers, I was wondering why some microphone do pick up their own speaker sound and other don't
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuvwacw"
],
"text": [
"It's usually software trying to filter out the specific sounds it knows are coming from it's own speakers coupled with directional microphones that only pick up sounds from a narrow area. The speakers typically sit outside this area and the computer what knows what sounds it's speakers are making and attempts to filter out that sound. So the differences come from how much money and effort the manufacturer of the system put into that feature."
],
"score": [
3
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
h9cnvu
|
How do hackers get your password without you ever giving it away?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuvwmkn",
"fuvx0yo"
],
"text": [
"If your password was a real word or word combination they could've bruteforced it with a dictionary attack. Or they hacked the server that stores the passwords. But you'd probably know about that big security breach. Or you downloaded a virus that has simply sent them your password for a specific program. Discord has one floating around atm for example.",
"If you use the same password for several websites and one of those websites gets hacked, and the hackers get your password, they can try it on lots of websites to see if it works there too"
],
"score": [
6,
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
h9dcnx
|
An article today said using your phone battery below 20% and charging it routinely above 80% reduces battery life...what causes this and is it the same process at both ends of the range?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuw5rbw",
"fuw041a"
],
"text": [
"Someone has already answered the question, but I’d like to add that most new phones are aware of this and will stop charging at 80%, but show you 100% to represent that this is as fully charged as the phone should be. They will also turn off at 20%, and represent that as 0%. Basically the battery indicator lies to you so that it can extend the life of the battery.",
"it's a chemical reaction to charge and discharge a battery. chemicals rearrange and move around to accept extra charge. When you charge it fully you're cramming as much charge as possible into the cells, causing the reactions to reach their most extreme levels of charge. this causes an extra stress on the chemical reaction, which over time, degrades the charge carrying capacity of the cell. similiar on the lower end, you're squeezing every last bit of charge out of it which has lasting effects on the chemical structure. the difference is pretty minimal though, i've always charged my phone fully every day and it still lasts me a few years"
],
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10,
6
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"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
h9eeu6
|
How do activity trackers know when I'm asleep? How they deduce REM sleep, deep sleep etc?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuwat25",
"fuwrtqg",
"fuwzocs"
],
"text": [
"I believe they just measure your heart rate. It goes down significantly when you go to sleep",
"Heart rate monitors combined with the accelerometer (sensor that tells if you're moving) then put through an algorithm that includes normal sleep patterns. So, you would see the heart rate drop, light movement (non-REM sleep) for 90 minutes, followed by 10 minutes of no movement (REM sleep), then 90 minutes of light movement, 10 minutes of no movement. The algorithm can infer that the 10 minutes periods are REM, but it can't confirm it. You would need some sort brain wave monitor to be absolutely sure you're in REM.",
"They do it by Actigraphy. Smart watches mostly come with extremely sensitive motion sensors, which keep a track of our movements in every direction and then translate those movements into sleep patterns. Still, calculation of REM sleep in particular is not very accurate as we have to do an EEG to record brain waves during REM sleep. They mostly indicate whether a person is asleep or awake."
],
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35,
15,
5
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|
[
"url"
] |
[
"url"
] |
|
h9g9kk
|
Why are apps on phones so much smaller than on PC?
|
A casual app on phone is between 1 and maybe 30 MB. It's very rare seeing a that small application on computer. Why is there such a big difference?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fuwh6gg",
"fuwux05"
],
"text": [
"Storage and memory is much more limited on phones compared to a PC. Also the processing power on a phone is much smaller so it takes longer times for them to read information. This means that large files with large amount of data either won't fit on your phone because it takes up too much space, or the phone will be too slow to process the data compared to what we think is acceptable. Usually phone apps also have less features than their PC counterparts due to memory, processing power or that the functionality is not present in the phone itself to support the feature.",
"> It's very rare seeing a that small application on computer is it though? at a glance: 7zip: 7MB coretemp: 2MB internet explorer: 5MB notepad++: 7MB windows media player: 9MB windows photo viewer: 6MB paint: 6MB magicISO: 4MB it's no different for games either. many desktop games are comparable to mobile games, their size is just hidden because they're in-browser"
],
"score": [
12,
9
],
"text_urls": [
[],
[]
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|
[
"url"
] |
[
"url"
] |
h9jvky
|
How does ram exactly work and what happens if you don't have enough in your computer?
|
I am building a new conputer and apparently dont have enough ram which causes it to crash sporadically. Curious as to how and why that happens
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fux1w7o",
"fux1wij",
"fux1gpd",
"fux1dc6"
],
"text": [
"RAM is the memory used by programs and the system to do the functions they need to do. Picture it like your dining room table. Now let’s consider best case scenario, you have a huge table (or a bunch of RAM). With your very large table, you can invite all your friends to dinner at the same time. You can serve multiple courses and there is room for all the plates. There is room for all the guests to fit at the table, and there is room for them to all eat and enjoy themselves. Now let’s picture a 6 person table. Your family can eat just fine. Maybe you’re a family of 4 so you can invite a friend for each of your kids, but no more. Or you can invite one set of in-laws but not both at the same time. With 4 people you can have a decadent meal with several courses. With 6 people you may have to scale back how elaborate the meal is because you are starting to run out of table space. Back to RAM with excess RAM, the max your motherboard can address, you never run out of space for programs to work. With the recommended amount of RAM, you can operate in most scenarios without running into issues. Now the last scenario, the minimum required amount of RAM, or the 2 seater kitchen table. Your family of four can’t eat at the same time. They have to be fed in batches. If there are just 2 eating, you can have a normal meal, if you are eating by yourself, you can have an elaborate meal. With minimum RAM the system will prioritize what gets memory usage and what doesn’t, programs slow down because they have to wait for memory.",
"RAM is short for Random Access Memory, and programs need access to this special form of memory this to run. Imagine Thanksgiving dinner on a glass table, and each dish is a program. Food can only take up so much space on the table top, before no one is able to sit their plate down to access the food. More space, more food. Too much food, can crash the glass table.",
"You harddisk contains all the data but is too slow to communicate with you processor directly. This is where RAM comes into play. The data (programs) you want to use are loaded into the RAM so your cpu can acces the needed data really fast. If you don't have enough and your CPU needs data that is not loaded into the RAM it needs to replace data that currently in the RAM with data from the harddisk. This takes time, especially if it needs the discarded data again that was wiped to load in the new data. If you had more RAM it could load everything in at once and therefore no need (or less frequent) to wait for data coming from your slow harddisk.",
"When your computer runs a program, it goes into your harddrive, and finds the files. This is really slow though and if you were playing something like a video game, it would just run terribly. So what your computer does is it takes those files and stores them in RAM. That way it can read those files really quickly. If you run out of ram for vital functions like your operating system, your computer can crash because it's missing files to run the operating system. For windows 10 you need something like 4gb to run but you need 8 or more for it to work even moderately well. & #x200B; ELI5- All your notes are stored in a filing cabinet. You want to do your math homework but going back to the cabinet every time you look up an equation is just soooo slow. So you take all the notes you think you need and bring them to your desk so you can look through them quickly when you need them."
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