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g0pgaf
|
How was experimental CGI rendered before the mid-eighties?
|
I've always been fascinated with computers from long before my time. 1980s CG animation in particular is something I've always found oddly soothing. But a lot puzzles me about how it worked. How were things like [Carla's Island]( URL_0 ) made as early as 1981? If I were working as an animator at the time, what kind of program would I have used to create things like that? Weren't computers at the time only capable of simple pixel images at most?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnax9fl",
"fnaxyp0"
],
"text": [
"Those images were animated one frame at a time in a supercomputer at LLNL. Computers in 1980's were capable of working in 3D, just not in real time (I was at SIGGraph in 1980). Essentially you figured out each voxel (3D pixel) and color coded it. Then you rendered the 3D space to 2D with a camera algorithm. You printed the 2D image on a piece of paper and photographed it, or if you had one, directly to film. Then you developed the film and projected it. What's most \"breakthrough\" about Carla was that the water has a surface normal. This means that the moonlight can reflect off it based on the relative height of the water in two voxels. That's why the second half of the film is so dark, to show off the awesomeness of that algorithm.",
"Carla's Island was made on a Cray-1 supercomputer using a process called raytracing. This was a state of the art supercomputer in 1981 when the film was made. Raytracing works by having the animator define everything in the scene mathematically, including the shape/color/texture of objects, any light sources, and the location of the \"camera\". Then the compute goes pixel-by-pixel and goes \"What would the camera see at this pixel\" and calculates every bit (or \"ray\") of light that would interact with that pixel to figure out what it should look like. Then it goes onto the next pixel and does the same thing. The movie in question did some things to cheat and make life easier for the computer. For example the wave motion was periodic, so that a lot of the frames are actually identical except for changes in the colors. This meant that the super computer only needed to computer 144 complete frames. Then a much smaller computer could loop through that computed data an adjust the few things that changed (mostly the location/color of the sun/moon)."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
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|
[
"url"
] |
[
"url"
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g0rk69
|
how do LED’s work and why are they so much more energy efficient than light bulbs?
|
ELI5: how do LED’s work and why are they so much more energy efficient than light bulbs? (Chemistry)
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnbcn3y",
"fnbb83a"
],
"text": [
"Normal lightbulbs work by running electricity through a small wire (filament) and heating it up until it glows. Well when you heat something to be white hot its going to give off some energy as visible light but most of it (96-98%) is going to be given off as heat (IR radiation). Normal incandescent and halogen bulbs only turn 2-3% of their energy into light. LEDs work by exploiting some quirkier physics. If you take an electron that's hanging out in a material with a high energy level and then you shove it across a boundary into a material at a much lower energy level then it has to get rid of the energy difference, and to do that it gives off a photon with that energy level. If you tune the difference between the energy levels you can make red, green, blue, even IR and UV LEDs, but each LED is only a single color. The LED bulbs in your home have a layer of phosphor over the LED and this phosphor absorbs the violet-UV light that the LED is setup to emit and turns it into a much broader spectrum of white light which is what you want. LEDs have some losses because they need a power supply with some inefficiencies to provide the right voltages and currents for them to work, but a screw in LED bulb can turn 15% of the electricity it receives into light you can see while bigger commercial and industrial fixtures can be upwards of 20-28%. The upper limit for white mixing with a phosphor is about 44% so upper 20s is pretty close to ideal.",
"LEDs work just from the electrons in their components moving. They fit right in with the circuit and are efficient because they light up just from the electricity moving through them. Incandescent light bulbs light up because the electricity passes through them, through the filament of wire, which gets so hot it lights up. The efficiency problem is most of the energy is transferred into heat instead of light, and LEDs don’t get hot"
],
"score": [
8,
4
],
"text_urls": [
[],
[]
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|
[
"url"
] |
[
"url"
] |
g0sa1t
|
Why does the use of a power strip not reduce the quality of the appliance?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnbgahy",
"fnbigdb"
],
"text": [
"Why would it? The appliance still gets all the power it asks for; for all it knows, it's plugged directly into the wall. None of the outlets know or care what they are or what they're plugged into; the wall outlet just supplies all the power that's demanded of it, until it blows a circuit.",
"Most wall outlets have two plugs. You can plug two things into them and they get all the power they need and work fine. However, your wall outlets are generally able to provide much more power than just two devices need, even two devices that take a lot of power. So all a powerstrip does in this case, is allow you to use more of the power that is already being provided by the wall outlet, its just unused."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g0t14p
|
why is it that when it comes down to the final minute on a dryer there like 5 mins long?
|
I've sat and timed my new dryer when it reached 1 minute for it to end it took 5 mins why do they even bother saying theres one minute left when it's more like five every dryer I've had does this and I'm so confused.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnbkuhl"
],
"text": [
"Modern appliances are no longer based on timers for their programs like they used to. In order to save energy they have all changed to using the input from sensors to determine their program. However this means that they can no longer give an accurate time for when they are done as this depends on how the load behaves during the different cycles. In the case of a dryer it is fairly simple with two sensors, one humidity sensor and one temperature sensor. The dryer will dry your clothes at the temperature you set until the air coming from the clothes is as dry as you set. The timer is just a guess for how long it would take. There is some difference in what they do to display a more accurate time. The simple thing is to just display the time used in tests for that model for a typical load and then count down. If it reaches the end of the count down before the load is dry it will just sit at 1 min until it is done. However some dryers might adjust the time based on the last runs to account for how you use the dryer. They might also use more advanced techniques to calculate from the sensor data to an estimated time remaining. But a common thing that they tend to do is to not account for the time used for the air in the dryer to cool down after it is done. This is done so you do not get scolded with hot humid air from the dryer if you open it when it is done. So it will wait a bit at the end for the temperatures to go down before it is done. And if the timer is not accounting for it or estimates that it takes shorter then it actually is then it will sit there at 1 min remaining for some time."
],
"score": [
10
],
"text_urls": [
[]
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|
[
"url"
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[
"url"
] |
g0x9m3
|
If video game graphics were still measured in bits like with 8 bit, 16 bit graphics from the days of the Sega etc. Then how many "bits" would modern consoles like say, the Xbox One X or PS4 have?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fncaiu3"
],
"text": [
"64-bit Although \"bit\" is simply not an interesting way to measure stuff under this context, if it ever was. It doesn't measure the speed or performance of the system."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g0xloh
|
How does a nuclear power plant produce power?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnccmw8",
"fncd15e",
"fnccxuo"
],
"text": [
"A hot rock boils water which makes steam and pushes a turbine around to generate electricity.",
"They put the nuclear stuff in a liquid. The nuclear stuff does nuclear fission to get hot (that is the atoms break apart, releasing tiny stuff that makes other atoms break apart, the atoms breaking apart makes things hot). The liquid gets hot enough to turn to gas and gets pushed through a pipe. They put in some stuff to slow down the fission so it doesn't get too hot and melt everything. They put the hot gas into a kinda fancy propeller like thing called a turbine causing it to spin really really fast. The turbine is connected to a generator which is a bunch of magnets and wires which makes electricity when spun. This is where you get the electricity. The pipe then goes into a place where it's colder, so the gas turns back into liquid. They put the liquid back into the place with the nuclear stuff so it can get hot again. Do note, the liquid/gas never goes outside, if that happens, it is really bad.",
"Enriched Uranium or Plutonium Generates heat. It can generate *alot* of heat. In a generator setting the heat is absorbed by water in heat exchangers (there are several options) and boils into steam. The steam is then run through steam turbines, the turbines generate electricity and the condensed water goes back to the heat source to be boiled again. This is a very simplified version of events. there are many options, safety controls and other accessories to make sure the power plant stays safe, doesn't leak radioactive steam and doesn't melt down."
],
"score": [
26,
9,
5
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[
"url"
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[
"url"
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|
g11r47
|
Why does it take some time for the internet to come back when you restart your modem?
|
Why isn’t it like a radio station where you can turn it on and off and you can instantly get the connection? Why does it take long for you to reconnect when you turn off and then turn on your modem. Isn’t the internet just there? What’s happening exactly?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnd06p3"
],
"text": [
"Your router/modem (I'm assuming you are using a combo unit) has to begin two way communication with the ISPs modem and router on the other end. This involves first detecting and negotiating the data transfer over the physical layer (the coax cable) first - they determine what frequency to use, do signal quality tests, etc. Then you get link layer negotiations. Your modem logs in to the ISP's router with your subscriber credentials (which the router then has to check from a database) and other stuff also gets set up. Finally you have network layer negotiations, such as your router asking for an IP address for itself via DHCP."
],
"score": [
3
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
g13age
|
When you stop the installation of a software halfway through, what happens to the leftover files?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnd6zy6"
],
"text": [
"That depends. Normally the installater would revert the installation, deleting all the files it installed. If the installer was killed instead, then the files would be just left there."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g17g30
|
Why are .com, .net, .org more popular than other domains?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnduqfv"
],
"text": [
"They have been around a lot longer in the US. (With .edu) The recent ICANN moves to expand the top level domain space are mostly about new financial opportunities for the organization and the registrar-industrial complex. When you're launching new products that people don't need, this sort of thing happens."
],
"score": [
3
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
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|
g17xmx
|
Why is there a weapon that throws fire (a flamethrower), but not a weapon that throws really cold stuff, like liquid nitrogen?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fndxvz8",
"fne9baq",
"fndyde5"
],
"text": [
"Fire can be made easily with a spark and flammable liquid (like gasoline). When sealed in an air-tight container that liquid is fairly safe to carry around and not hot. Basically you can make fire on the spot. Cold, not so much. Liquid nitrogen needs to be transported as a liquid which means it must be kept cold. That makes transportation much harder. You can't \"make cold\" the way you can \"make fire\". At least not in enormous quantities so easily. If we had a cold launching machine I would not bother with air conditioning in my home and use that instead.",
"A lot of comments talking about practicality but a cold weapon in the same style as a flamethrower won't do any damage. Setting everything on fire will destroy it. Making things kind of cold won't hurt anything. Yeah if you caught a spray of liquid nitrogen to the face it could do some damage but we used flamethrowers to destroy bunkers. The nitrogen would suffocate everyone inside the bunker before cold did any damage.",
"Throwing fire around is easy - you disperse flammable material, provide an ignition souce and (atmoshpheric) oxygen and fwoosh, you get fire. Dispense the material at pressure and it travels far. make it gelatinous and it sticks and coats. Making a cold thrower is more difficult. To make things cold you need to remove heat from the atmosphere or whatever your cold-gell or whatever sticks too. And normal cold materials cold enough to suck enough thermal energy out of contact surfaces wouldn't be viscous enough to shoot out of a high pressure nozzle. We'd need some kind of chemical (or multiple chemicals) that when combined or exposed to air produces a massive and near instantaneous endothermic (absorbs heat) reaction. And while Im no chemist, Im not aware of any such thing that would work like that. The only way to do it with non-exotic stuff is to simply utilize a giant pressurized gas bomb - same gas expansion trick used in your refridgerator and air conditioner. Take a room temperature pressure gas, compress it very tightly then let it out/expand all at once. It will expand, draw in ambient thermal energy and things will get cool. But the amount of gas to chill-freeze someone for example would be enormous. I think some dry chemical fire extinguishers do have a cooling effect but thats secondary to the chemical snuffing the fire through oxygen deprivation. And as /u/WRSaunders points out, you could make a Liquid Nitrogen Thrower, but 1) that's incredibly dangerous and 2) unless you immerse something in it, any LN that gets thrown onto someone would sublimate off pretty rapidly. Either you'd need a metric shitton of LN and dump them in it or they have to be sprayed with it for minutes or hours, which begs the question of what victim would sit still long enough for that to happen. Plus, if you were dunked in a vat of liquid nitrogen you'd suffocate to death sooner than you'd freeze solid (like those morons who drowned in a swimming pool full of dry ice)"
],
"score": [
31,
4,
3
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[
"url"
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[
"url"
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|
g18ha5
|
How exactly movie double works
|
There are lot of actions scenes in general which are without a doubt are performed by other action Specialists using body double techniques. But the final cut of the movie looks completely unadulterated and real to eyes. How does this works?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fne28l9",
"fne1fq8"
],
"text": [
"Movie doubles are cast according to how much they look like the actor they're doubling for, and from what angles. There was a post not too long ago with [Karen Gillan and her doubles]( URL_0 ). Obviously, seeing any of them face for any extended time would be a dead giveaway. One of them is also significantly further away in facial features. However, for the most part, you wouldn't recognize their bodies are different from a quick shot at a weird angle. Depending on the shots, they will use cameras from angles behind the actor being doubled. They'll make cuts quick and often so you can't focus on the actor too much to see any discernible features. They'll throw in a few cuts of the actual actors face so that the illusion doesn't get too far lost. If they have to do a stunt with the face, they may find a way to obscure it (making sure hair is messy, arms are covering it up a bit, etc.), and possibly using CGI to map the actual actors face back on. If you've ever watched a Mission Impossible movie, you'll notice very different camera work in the stunts because of how much Tom Cruise does himself. A lot of face-on camera work, no helmet when riding a motorcycle, less quick cuts. Not only does he do his own stunts, he wants people to know he's doing them.",
"The close-ups and face shots are filmed with the principal actor, while side, back, and wider shots are filmed with the doubles, so you don't look directly at the face (at least not close up)"
],
"score": [
8,
4
],
"text_urls": [
[
"https://www.reddit.com/r/pics/comments/fpx29r/karen_gillan_and_her_doubles/"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g1d5ij
|
How does game streaming service (GeForce Now, Stadia) have little to no lag, while traditional remote desktops (Chrome Remote Desktop, Microsoft Remote Desktop etc) having significant lags?
|
Just tried out GeForce Now and amused by its little latency. But when I tried a traditional remote desktop (Phone to PC in a local network, so should eliminate the internet bandwidth problem), the lag is more significant than GeForce Now. I wonder is it the underlying technology is different?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnexphc"
],
"text": [
"Whatever remote desktop program you're running has to render *and then* encode the video feed of the desktop on the computer that you're connecting to. The encoding takes a little bit of time. That little bit of time, combined with the fact that most remote desktop programs are just really quickly slapped together without any optimization means that you get a bit of lag. GeForce Now and Google Stadia are optimized to the point that they've gotten rid of the lag involved in encoding the source video. One of the likely ways that they've done that is by running the server on a custom operating system or drivers that is set up to render video into an encoded format for streaming - essentially encoding the video for \"free\" from a computation standpoint rather than requiring a second process to do it."
],
"score": [
4
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
g1gy3m
|
Why does Netflix have region locked content?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnfj88r"
],
"text": [
"Because the license they have to distribute it from the copyright holder comes with a restriction. For example, a movie might have theater release plans that are different in one country than another, so you want your \"available on netflix\" dates to not screw with that plan. Or...a TV show has a distribution and syndication agreement in a place that is exclusive and forbids distribution online by someone else."
],
"score": [
3
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
g1iuij
|
How do microphones on some devices not pick up on their own sound?
|
Ex: When I put someone on speaker they can’t hear themselves on the other end.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fngkv2y"
],
"text": [
"the speaker and mic cut each other off when one is active. some cheaper ones dont do this and you can get feedback"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g1nm6g
|
What’s a subnet mask?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fngo54y",
"fngr0m6",
"fngnqab"
],
"text": [
"Computer networks assign addresses kind of like street address numbers. On a residential street, the first row of houses might be 100-199, second might be 200-299, and so on. Each house in that row has to have a number in that range. But computers don't work with digits like we do, they work with bits and bytes that are translated into numbers for us to more easily work with. Since all IP addresses need the same format, each one needs 4 sets of 8 bits (usually called an octet instead of a byte in this case). Let's say we're setting up a network 10.0.0.0, and we want to divide it into 4 sub-networks (you have to work with powers of 2 because binary). The sub-networks will be 10.0.0.0, 10.0.1.0, 10.0.2.0, and 10.0.3.0. We don't want any two computers in any of these networks to have the same address, so a subnet mask is assigned to each network that decides the address range that can be assigned inside that network. A subnet mask can look like: 255.255.255.0 or have a simpler notation, like \"/24\", which refers to the number of bits FROM THE LEFT that define the subnet, so no address is assigned outside of it. So a /8 subnet mask would be 255.0.0.0, and the binary would look like this: 11111111.00000000.00000000.00000000 A /12 subnet mask would be 255.240.0.0 binary: 11111111.11110000.00000000.00000000 So our networks would be: 10.0.0.0/24 10.0.1.0/24 10.0.2.0/24 10.0.3.0/24 You can subdivide any network by making a bigger mask. If our last network was 10.0.3.0/25, then the binary for the subnet mask would look like this: 11111111.11111111.11111111.10000000 So the first subnet 10.0.3.0/25 would only assign addresses from 10.0.3.1 to 10.0.3.127. 10.0.3.128/25 is now a whole seperate network, and any networking device that gets an IP address and network mask can tell which other addresses are in the same network.",
"If an IP address is like a phone number, a subnet mask can be thought of as the country and area code. For example, let’s say all SF phone numbers have the area code of 415, so a typical SF number might look like 1-415-555-1234. By using a subnet mask you can define what number range are usable “inside” your area (for IP addresses this is typically a block of addresses a corporation or ISP owns). This works the same for country and area codes. A larger subnet mask covers more digits, leaving you a smaller set of phone numbers to use. A smaller subnet mask gives you a much bigger set of numbers. If you have a small region, you might mask away the first 6 digits, leaving you just X-XXX-XX5-1234, which would give you 99999 usable numbers inside your “subnet.” This would be a /6 mask. If you have a huge region, such as the city of SF, you might mask away only the first four, X-XXX-555-1234. This /4 mask would leave you with almost 10 million numbers. A even larger mask is needed if I asked you to give me a subnet mask large enough for all numbers usable inside the United States. That would be a /1 mask, which would look like X-415-555-1234 or 10 billion numbers available for assignment.",
"An IP address is one of a number of addresses you can be assigned. The addresses can be logically grouped together in sections or subnets of addresses. This can be for a number of reason from manageability to efficiency and other reasons. The subnet mask determines how the address you have has been placed into a subnet, is it in a group of 32, 64, 128 etc. It can be far more complicated than this, as an end user, usually you wouldn't worry about this. An example of where it would be used could be a business ISP giving a company a range of IP addresses, they might say you can have 123.123.123.1/24. This tells the end user that they are allowed to use 123.123.123.0 - 123.123.123.255, the mask would be 255.255.255.0. /24 at the end is the CIDR notation (shorter name for) for the subnet mask."
],
"score": [
7,
5,
4
],
"text_urls": [
[],
[],
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|
[
"url"
] |
[
"url"
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|
g1sczr
|
Why does a computer have to restart to install updates?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnhc991",
"fnhbj44",
"fnhbs3l"
],
"text": [
"For the same reason you cant replace engine parts in a running car, because its going to crash if you do.",
"You can't update files that you are currently using. So when you restart it allows the new version of the files to be used.",
"It should (and it would be technically feasible to create an operating system that does). But the fact is that on any given windows computer there are dozens if not hundreds of small programs running in the background, some are only set to run once when you start your computer (so they dont permanently hog ressources). some can be restarted, but because some of them depend on some of the other programs running in a certain order (or not running yet!), it is just a whole lost easier to implement some of the changes you make when you update/install software when you boot up the thing the next time. this allows both Microsoft AND the developer of the software you're updating/installing to simplify the whole process because there is a certain amount of standardization."
],
"score": [
6,
3,
3
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"text_urls": [
[],
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|
[
"url"
] |
[
"url"
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|
g1vchk
|
How do airplanes measure the speed they’re travelling at?
|
I would also like to know how boats do it too if anyone can answer that also? Sorry, they’re probably very simple answers.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnhtid0",
"fnhv7a1"
],
"text": [
"There are multiple answers. Virtually all involve distance/time calculations. * GPS * Air flowing into sensors * Inertial tracking * LORAN (radio navigation) * Radar/transponders You could also go old-school and say, visual navigation (stars/landmarks). Boats can do all of this, too, although the air/sensors thing wouldn't really work. Boats can also measure the rotation speed of their propellors, because water is always the same density (more or less) and the propellor is a fixed size. So, they know how much thrust they're generating in the water. The boat would have to know the current speed/direction in order to get an accurate reading. Planes can do this, too, but it's more complex because air pressure/temperature makes more of a difference than water.",
"Depends on WHICH speed you want to measure. There are a few different speeds we would want, depending on what we are trying to do. For things that have to do with the airplanes dynamics itself and how the airplane is flying performance-wise we use airspeed which measures the amount of airflow passing over the aircraft, which is measured by the pitot tubes placed on the aircraft. Air goes in the tube and is displayed on the airspeed indicator in the cockpit. This has nothing to do with the aircraft's speed across the earth, purely the air going over the wings. If the plane is sitting still on the ground, pointing into a 10 knot headwind, then the airspeed indicator will show 10 knots of airspeed. This is the most important speed to know because it directly influences how the aircraft is behaving, as well as your takeoff and landing calculations. For navigational calculations, for instance how long it will take to reach a certain point, then we need to use GROUND speed, which is measuring how fast we are traveling over the surface of the earth. To get that speed we, in modern times, use our GPS receiver which is usually displayed on our moving map displays. This speed is most important for fuel and flight path calculations."
],
"score": [
7,
6
],
"text_urls": [
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
g1wv4a
|
Why is it easier to key in things behind a green background rather than a background of some other colour?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fni2muw"
],
"text": [
"Green and blue are the furthest colours from most human skin tones, so there is less of an error when you are keying people, if you are keying something else you can use other colours"
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g1xxl9
|
During the time where the light bulb was invented, how did they have accessible electricity? Did they have power plants like they do now? Did they use some sort of battery?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fni9r3q"
],
"text": [
"The answer is, \"the same way they do now.\" That is, electricity was generated by a generator, which could be powered by a water turbine, a windmill, a gas engine, etc. The generation of electricity came before the invention of the lightbulb, in other words."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g1z448
|
Why do some games on windows return to the desktop when you press Ctrl+Alt+Del and some don't?
|
When I run a game on windows and want to open another app without exiting the game, sometimes it opens the task manager but doesn't let me use other apps, and sometimes it returns to the game when I open task manager. How does it exactly work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnio9sg"
],
"text": [
"I dunno exactly what's going on there, but allow me to give you a new keyboard shortcut that's more useful for this purpose: Alt+Tab. It just switches between running programs."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g20pnf
|
If the speakers on my computer can replicate the sound of my voice, would I be able to create the sound of my voice or anybody else's from scratch without ever recording it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnirk0b",
"fnis0i2",
"fnis2cg"
],
"text": [
"its possible, but difficult to make voice from scratch. mostly generated speech just stitches together lots of different voice clips, smooths it over so it sounds ok. There are completely artificial voices but they're more difficult and intensive",
"Theoretically, yes. Although, a voice is extremely complicated, so even original voices still work from modified samples as opposed to being created entirely from scratch. It would be virtually impossible for you to recreate your voice perfectly just by typing in lines of code or something, without recording say, your neighbour first, and altering the sounds until they fit your voice.",
"Technically yes, you would be able to create any sound you want, including a speech with a voice you want, but it would be time consuming as you would need to 'design' out every millisecond of the sound/speech. A sound at basic levels is produced at a certain frequency and amplitude. Frequency would determine the pitch while amplitude determines the volume. For every word you say, their frequencies and amplitudes are different (think saying 'Ah' vs saying 'Ooh'). What makes your voice different from other people is that their voice is higher or lower pitch, hence higher or lower frequency voice. When you record a voice/sound, sound waves travel to the microphone, which has a component that changes voltage and current based on the frequency and amplitude of the sound it received. It can then 'transcribe' it into the computer as audio data, containing information about the frequency and amplitude of the sound it recorded. Using speakers, you recreate the physical sound from the data. Since the computer saves frequency and amplitude as audio data, you can create your own original audio data. It would take a lot of effort, but it is entirely possible."
],
"score": [
11,
8,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g22q9e
|
why can’t we use cellphones on a plane, even today after many years, when can’t we yet?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnj82ro",
"fnj7zgb",
"fnj87gr",
"fnjd4j0"
],
"text": [
"Cell phones are very short range radios. Their max range is 6 miles (10km). On the ground there are lots of towers, and protocols for switching from tower to tower as the phone moves around. Alas, planes move very fast, so that's a different tower every minute. That's faster than the code that runs the towers can support. This means that dropped calls are very common.",
"Because voice calls are annoying for everyone else around you, who are stuck there listening to You.",
"The official reason is that it causes interference with the airplane radio signals, but that has never been actually proven, so it's more like a \"to be safe\" thing, and also to keep the airplane less noisy.",
"Back in the days of 1G and to some extent 2G the analog waves used and high power would cause the Navigation radios to distort a bit. Airplanes navigated by (and still do as a backup to GPS) off of Navigation aids called VOR (VHF Omnidirectional Range) that operate from 108.0 to 117.95 MHz. FM radio is right below this and aviation communications are right above this. If you've ever heard your computer speakers do that \"dit dit dah dah dah dah\" sound right before you get a text or call, imagine that happening. Now the needle that would point to the beacon will twitch with those. When landing and flying an ILS (Instrument Landing System) these needles are extremely sensitive, measuring movements of the aircraft as small as a few feet. Those twitches could make the needles show an error and that error means the plane could show it is lined up to a runway when in reality it is lined up to a building or a tree. Since digital signals came along this isn't a concern anymore. Now it has to do with the old law still being there because adding laws is easy, but removing them isn't. Our headsets now even have Bluetooth capabilities to connect to our phones. Sure it is so we can \"play music\", but I routinely make calls from the air. Seems 6000 feet above the ground is the average no go point. Above that there is no signal. Oh, and at least T-mobile can switch towers at 250 mph, so don't worry about driving too fast for the network."
],
"score": [
16,
11,
9,
7
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2315j
|
how is music made?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnj5p9a",
"fnj5ekg"
],
"text": [
"There are *many* different approaches. It doesn't particularly matter where you start, cos whichever piece you start with you just design the other pieces to fit it. Also, the lyrics *don't* always perfectly match the beat. There are loads of songs that have to use nonsensical lyrics, skip syllables, add syllables or even make up new words to get the lyrics to fit.",
"Some people start with lyrics, some start with melody, some start with percussion. It all depends on the individual."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g23ccy
|
Do our smartphones constantly check (i.e. every second) for push notifications?
|
Or do they just receive it without even checking? If I were sitting on a chair and a banana hit me, I’d know it hit me just by being conscious. Is it the same with phones or would I need to constantly ask someone if there are any bananas coming my way? Hope I formulated the question right.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnj7b9z",
"fnj8dln"
],
"text": [
"By definition “push notifications” get pushed onto the phone. Your phone isn’t checking for them, just merely in the line of sight of the banana.",
"Your phone keeps a constant TCPIP connection open to the push notification gateway. The gateway knows what connections are associate with what device and app unique IDs. When the push gateway gets a message to deliver, it looks at the destination unique ID and send the message down that IP connection. The phone receives It and does whatever."
],
"score": [
8,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g240qd
|
How are CGI model movements executed in an efficient manner?
|
There are many, many things that baffle me about CGI (like how the hell the models are built so detailed using just a damn computer mouse, how textures look so good, how is CGI integrated seamlessly with live-action, ect ect). & nbsp; But one thing I cannot wrap my head around is how MOVEMENT of CGI models works. When detailed CGI models are rigged they have an obscene amount of movement options added to give them realistic appearance (I remember reading that Woody in Toy Story 1 had 56 facial controls... and that was 25 years ago). To program an animation as simple as walking you would have to make the legs move in the right trajectory, then the torso and shoulder movements have to fit in. Accomplishing all of that by slowing manipulating individual micro-movement controls one at a time sounds unbelievably painstaking. Like even worse than stop-motion. & nbsp; Also while we're on the subject, why haven't any CGI assets ever leaked from say, Disney Pixar? If that happened then surely people could make their own movie scenes and stuff for things like Shrek and Toy Story, and it would be fun in a juvenile kind of way (processing power needed for rendering surely wouldn't be a problem for the late 90's kind of stuff). Or we could watch animated movies from a different camera angle!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnjfej9",
"fnje6dd"
],
"text": [
"* > > why haven't any CGI assets ever leaked from say, Disney Pixar?* There are multiple reasons. * Mind-bogglingly tight contract language, with armies of people specifically tasked with controlling access. Seriously, the projects I've been in touch with had people whose *only job,* 9-5, M-F, was acting as the Fun Police. * Very few people will ever have access to all the bits and bobs. It's kept as separated as possible, so actually getting a complete set of data in order to leak it in the first place is difficult. * Relatively speaking, very few people \"work at Pixar.\" When you're watching the credits of a movie, it's mostly a list of people brought in for specific projects, and when the project is done, they're out of a job and need to go find a new project. Want to keep getting projects and stay gainfully employed? Make friends and don't fuck around. Word travels *remarkably* fast. Most leaks *don't* come from the people you think. The leaks come from the folks on the margins, in other disciplines like marketing, PR, studio corporate, etc.",
"* > > Accomplishing all of that by slowing manipulating individual micro-movement controls one at a time sounds unbelievably painstaking. Like even worse than stop-motion.* Yes, that sucks. It's why they *don't* do it that way. :-) Advances in rigging also include advances in how the individual components of the rig work with each other. You don't have to control every little detail. You can move one set of controls, and it programmatically moves other sets according to the parameters you set up in the rig. In other words, if you move Woody's arm, the rig can be smart enough to know that his shoulder, neck, torso, etc, *should* *move with the arm* in a way that makes sense for the character. Also, don't forget about motion capture and mo-cap libraries. CGI for, say, a Marvel movie *starts* with tons and tons of data already available, either from the actors, stuntmen, or even data from completely different movies that can be repurposed. The genius comes from adjusting from this starting set to make something wonderful. But just like a chef doesn't start making dinner by harvesting wheat, the animators aren't always starting from step zero."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g25qu0
|
How come films and tv shows from the 60s to the early 2000s look so different from films today?
|
What I'm trying to say here is: why the image looks so unique? I don't know if it's because they were not filmed with digital cameras and they didn't have the great picture qualities we have nowadays, but they definitely feel like they were from the past, like if you're watching Back to the Future you think "this is definitely something that was filmed in the 80s" no matter if you're watching a remastered 4K edition or something, it always looks different. Just to give you a clue, whenever someone tries to make a modern film "look old" they barely resemble the aesthetic (most of the time it looks like if an Instagram filter has being applied).
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnjnouy",
"fnjzm1d",
"fnk1huw",
"fnjw22n",
"fnkieej"
],
"text": [
"35mm film has a very high resolution if properly scanned, but many videos from that time period were scanned to be shown on television so they were scanned at 480p. Hence they look blurry. They are rescanning the old films, but some they haven't done yet. Take a look at the 1080p versions of some of the old TV shows they have rescanned, like Perry Mason, and Andy Griffith, you'll be amazed at the clarity.",
"Kodachrome. Different color balance in old movies. Different color correction in newer movies for artistic reasons.",
"Part of it was the idea that there must be NO shadows anywhere in the shot. Careful lighting to remove all shadows. Nowadays we accept shadows as a normal thing.",
"I'm far from an expert, but I think a lot of this also has to do with the filmmaking techniques that were popular in different eras. Different camera filters, lighting, even colour calibration and temperature. And of course we're just going to keep getting get more and more used to high frame rates and resolutions so it will be even more noticeable.",
"As a filmmaker I would say that process that has the biggest impact is digital color correction. There are a ton of subtle things that have changed, but manipulation of the image in computers to change the colors and sharpness/diffusion has the biggest effect. Think of the biggest difference between a film stock and a particular digital cinema camera or a vintage lens and a modern lens and assume that it would be only the first 10% or so of how much you could “stylize” the image with post color correction in a matter of seconds. What I mean is that you can do 10 times as much in post to manipulate and fine tune the differences."
],
"score": [
16,
7,
6,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g25rc2
|
What exactly happens during a clock cycle in a CPU?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnjslzn"
],
"text": [
"Ooo, I used to work on these, and I think like a 5yo, so this should be right up my alley. Remember the red light green light game in school? Each time you hear one red and one green, that is a clock cycle. Think of each kid as a different part of the CPU. Some kids are faster than others and can get farther than others in a clock cycles. Think of that less the capability of the kid but the amount of work that happens within a clock cycle. In order to make a CPU work, the kids have to get to a far enough distance or there are errors in the CPU. ELI15: CPUs are broken down into different units. There's parts that do integer arithmetic, floating point arithmetic, memory/cache that store answers, controllers for all of the units, etc. Let's say as a basic example, you want to add 1+1. The steps without any optimization could look like this: 1. Get the code from you program (add these two numbers from memory spots A and B and store it in C) 2. Get the values from memory locations A and B. 3. Add them in the integer arithmetic logic unit 4. Put the new value in memory locations C This example could take 4 cycles to perform. Modern CPUs have insane optimizations that lower the cycle per instruction."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g27971
|
Why is it recommended that we wait a little bit after turning something off to turn it back on?
|
Also why can we restart PCs since this contradicts this recommendation?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnjwy23",
"fnk79ln",
"fnk96rn"
],
"text": [
"Most electronics contain capacitors. Capacitors act like little buffers to even out current in a system. A bit like having a header tank in a plumbing system. Think of them like tiny batteries that are constantly charging and discharging. When you turn off an item, the charge in the capacitors doesn't go away straight away. You have to wait for a few seconds to allow it yo dissipate. The charge can be enough to mean that certain buffers or bits of memory aren't properly reset, so without waiting, the restart alone doesn't always fix it.",
"You can think of electronics having some energy still in the circuits. Imaging letting off the gas in your car, it doesn't stop immediately. You the to the the circuit come to a \"complete stop\" before turning it back on or some of the messy settings that you are trying to wipe clean could still be saved.",
"Nobody really addressed the restarting a PC part. When you tell Windows to restart, the computer itself never really shuts down. The hardware stays powered up, and just goes through the boot process again. All of the physical components are still on. That's why sometimes a tech, or that computer savvy family member, will tell you to specifically do one or the other. Turning it off and waiting a few seconds does exactly the same as what the others have said: allows the capacitors to discharge."
],
"score": [
100,
7,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g29pbz
|
What is packet loss and what are packets?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnkac2n"
],
"text": [
"Your data isn't sent in a continuous stream like a river, but like gunfire. The individual bullets being 'packets'. Packet loss means that somewhere in the travel, due to some errors, some packets get 'lost'. Like the post loses some letters from time to time."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2bjim
|
Why is Zoom so dangerous and pose a security threat?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnkitjz",
"fnkmfev",
"fnkmtjm"
],
"text": [
"People can guess a random 16 digit code and join your room (unless this was fixed really recently). See: [ URL_1 ]( URL_0 ) There's also been some concern recently about Zoom being required by the Chinese gov to hand over their encryption keys if requested.",
"Unless I’m missing something, a password and a waiting room solve the security problems that have been encountered by schools. However, students (foolishly or maliciously) passing on the meeting id and pwd can still be an issue and could flood the waiting room I suppose. If there is some deeper security exposure, please educate me here.",
"There were also some issues with data sharing with Facebook, but those were resolved when Zoom removes old code that allowed people to use their Facebook credentials to log in (like a bazillion other online services do). The issue was with the code in the Facebook SDK - software development kit - provided by Facebook, not some malicious intent by Zoom to make money selling personal data to Facebook. The real problem with Zoom is that they onboarded a ton of new users because of the pandemic instead of growing to that size organically, so a lot of clunky back end processes hadn’t evolved - like still defaulting to no password and no encryption. Just my opinion."
],
"score": [
6,
3,
3
],
"text_urls": [
[
"https://www.reddit.com/r/trashy/comments/ftotp1/joining_a_random_zoom_meeting_nude_where_there_is/",
"https://www.reddit.com/r/trashy/comments/ftotp1/joining\\_a\\_random\\_zoom\\_meeting\\_nude\\_where\\_there\\_is/"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2l295
|
What exactly are cookies that websites are using?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnm1s72",
"fnm2wd5"
],
"text": [
"They are like small notes that the website asks your browser to keep and give back to the website next time you visit it. They are typically things like your personal settings on the website, your choice of language etc. but they can also hold information that proves who you are to the website so you don't have to type your password in every time you click on a link.",
"When you visit a library, the library issues you an ID card. This is like a cookie. A web server issues cookies to you to personalize your experiences on their websites. You use your library card to check out a book, and over time the library recognizes your choices and can make suggestions for you based on that data. Cookies are sent back to the server when you visit it and thus the sites cater more to your choices. If you use amazon, you’ll see the part of the page that suggests items to you based on your cart items, that’s what cookies can do. It makes the websites you visit closer aligned to what the server thinks you need."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2lglc
|
What's the difference between mechanical keyboards and normal keyboards? Why do pro gamers prefer mechanical keyboards?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnm4gyt"
],
"text": [
"imo, it's mainly marketing. but there are build quality differences between a mech keyboard and cheapie membrane keyboard. mainly in the tacile response, ie the keypress feel. the keys themselves have different range of movements until when the key is actually registered and how far you need to press and how much force you need to use. and of course the clicky noise. we actually started off with clicky noisey keyboards back in the day. then people didn't like them because they made too much noise/too bulky/too expensive and we all switched to cheapie membrane keyboards that don't have a good tacile response. but then when esports took off, pc accessories started becoming a huge market. so a lot of companies started making them and paying programers to use them. but one thing that most mech keyboards have is N-key rollover (which you can also get from non mechnical keyboards), if you hold down multiple keys in cheapie keyboards, some only remember the last key you pressed. so if you're trying to do something fancy like strafe left, while moving forward, and jumping while also changing weapons and checking the scoreboard while also using your push to talk button... yeah that might not work as you intended."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2ma41
|
Why are people afraid of 5G towers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnm8otp"
],
"text": [
"Because they’re idiots. It’s just another conspiracy theory that follows this mode: something is happening, there are perfectly reasonable explanations for what is happening but due to my upbringing, political ideology and worldview, I refuse to accept those explanations because they’d require me to take responsibility for my actions, hence find something I don’t understand and blame it on that. In 1900s it was electricity - it was supposedly causing everything from infant deaths to suffocation to madness..."
],
"score": [
15
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2mzwz
|
Why there are extra cooling systems(like fans etc.) for GPU and CPU but nothing for RAM?Isn’t that get hot?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnmdoxr",
"fnmdvub",
"fnmehnp"
],
"text": [
"Ram does get hot, but not enough to be a problem, I think that is because ram isn’t really performing much compared to the CPU and GPU, only some sections being accessed at a time, and also the heat is spread between all the chips Nevertheless some “gaming” ram has metal heatsinks, but they are also very much for show, there have also been some water cooled ram modules but that’s way overkill",
"There are some esoteric solutions, but RAM simply doesn't generate the same amount of heat as processors so there is normally no issues with normal heat spreaders. Older processors and GPUs, and even low-power modern ones can survive with just passive cooling and the system airflow.",
"First, [there are cooling systems for memory]( URL_1 ) - that online store has a whole section of them as you can see. But yes, RAM doesn't get as hot as CPU and GPU. CPU is usually OK with just the standard factory fan, you only need to get a better cooling setup if you overcock the CPU past the factory specs. Overclocking increases the voltages and power that have to go through the CPU by a lot, so that's why extra cooling is needed. GPU is typically designed to operate \"at the cutting edge\", so it requires serious cooling. The two components inside a graphics card that need cooling are: * the graphics processor itself, which can ramp from 0 load looking at a desktop, to HUGE load trying to render a complex game with realistic visuals and physics, * and the bank of [voltage regulators]( URL_0 ), which must change the input of 12V DC to the internal voltages of, for example, 1.23 V DC, extremely accurately (no fluctuations in the 1.23 V) while maintaining power levels at 100+ watts. A lot of power going through those regulators, basically, requiring lots of cooling of the electronic components."
],
"score": [
8,
6,
3
],
"text_urls": [
[],
[],
[
"https://www.ozone3d.net/public/jegx/201004/asus_eah_5830_pcb.jpg",
"https://www.newegg.com/Memory-Chipset-Cooling/SubCategory/ID-572"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2o5h8
|
Why are Solid State Drives so large when you can fit 1 Terabyte of information on a MicroSD card?
|
Wouldn't it just cost more to produce? Do MicroSD cards with 1 TB of information cost more than making a Solid State Drive that also holds 1 TB?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnmlte4",
"fnmki1p",
"fnnb901",
"fnnpe71"
],
"text": [
"A micro SD card and an SSD have very different rates when they transmit data to a computer. A micro SD card will transmit data at a rate of around 25 Megabytes per second which would take 40,000 seconds (11.111 hours) to complete a full transfer of a 1 Terabyte data file. A SSD can ideally transmit data at a rate of 550 Megabytes per second which would take about 1818 seconds (30.3 minutes) to complete a full transfer of a 1 Terabyte data file. Overall, it's when you want to use it that matters. A micro SD is great for cameras and smaller devices that do not require a fast data rate to function. A gaming PC or a supercomputer would not run very fast if it were running off of an micro SD card but will run fine when using an SSD. Sorry if I did not explain that simply enough. Let me know if you want more clarification. I love this stuff. Edit: I am merely giving an example to understand the difference. It is definitely not the best case scenario. These are merely averages I searched up to give the example simplest.",
"SSD hard drives on SATA connectors have performance and longevity expectations. Users fully expect to run the SATA connection at full speed for reads, and pretty close for writes. Drives are usually warranty'd for either 1/3 or 1 full copy of the disk written to per day, for the duration for the warranty on the disk. These are things you don't get on SD cards. That stuff takes space for the additional chips, including the processor, RAM for the processor, and multiple storage chips accessed simultaneously to make up the speed needs. Now, if you really want to make use of the size of the disk and you have the cash, you can get a ~16 TB SSD in the same physical size for SATA SSD disks. I think they cost over $2,000 each though.",
"SSDs are a more-sophisticated, higher-performance design of otherwise the same basic thing as an SD or micro SD card. They have additional or more powerful components; They have cache that is basically RAM (even faster than the actual storage itself. Helps make reads and writes almost instant, up until the cache gets too full to be helpful.) They have a microcontroller (brain) capable of speedily zipping data around and wear-leveling (spreading reads/writes over the whole storage area to prolong the life of the whole drive). They probably do a little bit of error detection and correcting. Stuff like that. But even then, the SATA 2.5\" drive size is pre-determined since before SSDs were a thing. To see how small SSDs can be, crack open a 2.5\" SATA SSD. It will probably be a small circuit board inside taking up hardly that much of the space taken up by the outer shell at all. Source: URL_0 (Whole video is worth a watch if you're curious about SSDs. Goes into what makes an expensive one more expensive, what a good SSD should have, and some objective speed benchmarks for comparison.) Easier still, take a look at M.2 SSDs. These can be the size of a couple or a few full-sized SD cards. And some of them are even faster than the larger 2.5\" drives, if they support the NVMe standard. Tl;dr they are bigger because they have more, better components that have to operate at higher performance. But the big old 2.5\" ones are big mostly just because the physical standard needs to be backward-compatible, with mounting screw holes on the sides lining up with mounting solutions for existing hard drives.",
"It mainly has to do with speed. SSD drives are fast because they use multiple flash chips at the same time, this way the work of storing or reading data is split over multiple chips and can be done faster. In an SD card, there is only a single flash chip which has to do all the work, so it is slower. Power is also an issue. Most devices meant to read SD or microSD cards are low power (phones, cameras, MP3 players), so SD cards are designed to use very little power. SSDs are optimized for performance, they use extra electricity in order to speed up reads and writes. SD cards range in speed from 10MB/s to 100MB/s or so. SSDs range from 500MB/s to over 2000MB/s, which is up to 200x faster than SD cards."
],
"score": [
80,
9,
6,
3
],
"text_urls": [
[],
[],
[
"https://youtu.be/mnk6gnOBYIo?t=10m30s"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g2ocd1
|
When NASA made the first space suits, how did they know what space would be like? I.e., how did they know what to put on the suits?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnmlkce",
"fnmo3xi",
"fnmsg63",
"fnmomku",
"fnmramt"
],
"text": [
"It was theorized to be a vacuum hundreds of years before we went to space. We can also produce vacuum chambers here on earth to design and test such a suit. Keep in mind we’ve been making pressurized suits for several decades before space flight including for deep sea diving.",
"Worth noting that the first spacesuits were hand sewn and custom tailored by the Playtex Corporation, the people who make women's lingerie and underwear. They were the only ones that could make a suit to the tolerances demanded by NASA. Stitches that were 1/32nd of an inch, consistently, through 21 layers of cloth and rubber...all over the length and breadth of an entire suit. And although it got spun off into its own division, the same company still makes them.",
"NASA didn’t make the first space suit. And actually the Russians were the first to send a man into space not America. The origins of the pressure suit are below. Captain hawthorn c grey made a high altitude balloon flight and died. URL_0 Following this another pioneer of flight Wiley Post developed the first pressure suit based on a diving suit in an attempt to fly higher and faster. Picture of him in the first pressure suit attached URL_1",
"They had been sending sounding rockets, probes, and experiments into space since basically the end of WW2. The German V-2 actually left the major part of the atmosphere when bombing England. Finally, they actually used modified weather balloons to send Joseph Kittinger to the edge of space to test a spacesuit. He held the record for highest free fall skydive until Felix Baumgartner broke it with Red Bulls help.",
"We've known since antiquity that space was a vacuum. We've been able to directly measure the temperature and pressure environment in space since the late 1940's through both sending rockets and high-altitude jet test pilots. We sent probes into space since the late 1950's. There really wasn't anything we didn't know about how to make a functional (if not optimal) space suit by the early 1950's because, again, we had high-altitude test pilots flying jets in what were essentially space suits by that time."
],
"score": [
43,
35,
5,
3,
3
],
"text_urls": [
[],
[],
[
"https://en.m.wikipedia.org/wiki/Hawthorne_C._Gray",
"https://imgur.com/U5P43Sz"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2pqiy
|
How do we know exact time? Do we all copy one clock and if so, how do we know it is correct?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnmufmz",
"fnmvqzi"
],
"text": [
"The main way to tell the clock is by using an atomic clock, there are different around the world, the us uses one in colorado iirc, eu uses one somewhere in germany. Theyre cesium based, as we define a second as the time elapsed between 9.192631770 x 10 9 wobbles (dont know the way to explain this in english, sorry xD) between two levels a cesium atom. And the easy way to say why its correct is because we choose to collectively say that its correct. There is no \"actual time\" in the universe.",
"All the world's base clocks are coordinated with each other. That's why UTC is called Coordinated Universal Time. The base clocks communicate with each other all the time, making small adjustments to move the time as represented in the group forward consistently. UTC is based on TAI (International Atomic Time) a weighted average of hundreds of atomic base clocks located all around the world. It's coordinate by the BIPM ([International Bureau of Weights and Measures]( URL_0 )), a group of scientists."
],
"score": [
17,
6
],
"text_urls": [
[],
[
"https://www.bipm.org/en/bipm/tai/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2rbfc
|
How does a computer delete something from it's memory?
|
What happens to that information? How can it be destroyed?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnn349i",
"fnn37a4"
],
"text": [
"Information can always be destroyed. Imagine you have a line of ten pennies and you flip them all to 'tails'. The information of their prior state/orientation is gone. That's basically what computers do when they overwrite/delete data. Normally, however, when a computer is told to delete something, it doesn't actually delete it. Rather, it marks it to be written over with the next thing you save.",
"A lot of times stuff is still written on your drive after you delete it but it gets marked as available space. So, new things get saved over it and that’s when it’s pretty much gone permanent. That’s why you have recover deleted file/parts of deleted files using recovery programs"
],
"score": [
21,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g2sfrm
|
how do bot accounts work?
|
Where do they pull information from/how do they know what to say? And who makes/benefits from these accounts?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnnjjj3",
"fnnjno8"
],
"text": [
"If you specifically mean Reddit accounts, generally they'll write a program that looks at popular posts from the past, then reposts them. Particularly sophisticated ones will have networks of these bots, so they might have others that take the comments that were highly voted on those posts the first time they were made and then copy those, too. Their goal is to build up karma on an account and make it look like it has a normal posting history so that they can sell it to spammers who want to be able to advertise without looking like that's what they're doing. They think they're more likely to get you to buy what they're selling if they look like a normal redditor giving a product recommendation than if they're a clearly brand new account. That's why you should always report bot accounts reposting stuff if you see them. It's a lot harder for them to sell those accounts to spammers if they get banned or suspended.",
"Different bots operate differently and pull information from different sources. A bot is a program. It looks at certain things and takes actions based on criteria met. That application or program that we call a bot, in this case named auto moderator, runs on a server somewhere. ELI5 uses a bot to make sure all the posts start with ELI5. So it looks at every post made on ELI5. If has ELI5 at the beginning it ignore the post. If it doesn’t have ELI5 at the beginning, it takes the actions it was programmed to (in this case, removing the thread and asking the user to resubmit with ELI5 at the beginning). Other bots are more complicated, like a chat bot potentially. I don’t know that I’ve interacted with any of them — there are plenty of humans dumb enough to pass for robots, I don’t need to assume dumb things were written by robots. But most bots just see X or Y and do A or B. Who makes them? People who want to experiment with a practical use for their programming knowledge. People who want to help Reddit mods. People who are bored and just want to tinker. I know I didn’t hit all of your points, but I hope I helped. What did I miss?"
],
"score": [
92,
19
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g2shvs
|
Is the technology behind Zoom actually super groundbreaking or advanced compared to older videoconferencing options like GoToMeeting/Skype/Hangouts, etc?
|
Why does Zoom seem so much more popular than those older conferencing options? The vid quality is just better? Or UI is easier? Or b/c you don't need to sign up? Thanks!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnna53v",
"fnnaad1",
"fnnege8",
"fnnr2p8",
"fnrkbxf"
],
"text": [
"No. None of these are particularly groundbreaking, nor are they trying to be, they just offer a service thats basically the same type of video conferencing that has been around for 40 years, albeit of course tailored to a more modern audience. These companies don't really compete on features of their product, they compete on sales. There are some groundbreaking video conferencing systems out there, but these are generally only used in high-end business and education and come with a significant price tag.",
"Zoom has a freemium business model, where a completely free version can be used for small calls. This attracts people to it. Alternatives like WebEx or gotomeeting had no such option.",
"A lot of the older videoconferencing options had problems with lag, stutter, failure to connect, difficulty connecting in certain network configurations, etc. Some of them relied on plugins that could be finicky to install or were often missing (e.g. Silverlight). Zoom pretty much \"just worked\". Most of the others now \"just work\" too, but they certainly carry some reputational baggage from the dark old days when things were hit or miss. So one part is being born late enough in the game that a lot of the enabling technologies (internet speed, network infrastructure, webcam driver quality, CPU/GPU performance) were mature. There is a web standard called WebRTC that is now in all the major browsers (Chrome, Firefox, Edge) that solves videoconferencing in-browser, without need of any downloads, and there are some services that are wrapping that in a reasonably easy to use way. Video conferencing is fairly complex from a network point of view, so there are lots of ways in which it's tricky to keep secure. Zoom has had a series of fairly careless-looking mistakes. To their credit they seem to be saying and doing the right things about it now, so they may yet earn back the trust they burned by their earlier decisions and mistakes.",
"It isn't ground breaking, it is just easy to use, and in the right place at the right time. If COVID hadn't happened, Zoom would have remained obscure. Zoom is slightly easier to use than some of the alternatives for a few reasons: 1. It offers basic service for free, while many other video conferencing tools require a payment. Even small costs are enough to deter a lot of people. 2. You don't have to sign up for an account to join a meeting. Skype, GoToMeeting, and Hangouts all require you to create an account in order to use them. 3. Zoom offers some tools that are useful for holding larger meetings and lectures, while some other tools like Skype are better for small meetings. For instance, Zoom allows for things like voting, or for a single user to administer the meeting and control how/when other people can contribute.",
"Texting and video conferencing apps have this phenomenon. Every few years someone invents a technology that already exists and everyone jumps on board like it is something new. The issue is security - the purpose of security is to keep unwanted people out. It is therefore always going to make things harder to use - you put a lock on a door, now the user has to know how to use a key. There is a three way relationship in applications - flexibility and capability versus usability versus security. They each are in direct conflict. Zoom is very capable and flexible, and it is easy to use. Any guesses how good it’s security is?"
],
"score": [
11,
9,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g2uypd
|
Why does movie volume vary so drastically from scene to scene?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnnp98d"
],
"text": [
"It's a thing that became more prevalent in the last 10 years or so. If I recall correctly, sound grading in movies usually just sucks these days. I don't remember if I made this up in a dream, or saw a video about it a few years back... Something about not remastering for broadcast vs in theater, or something? Might not be the case, but in any event, I've noticed it too"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2wbhe
|
What are internet cookies, and how do they work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnny3ks"
],
"text": [
"When you visit a website, the website wants to keep track of who you are and what you're doing so that it can improve your browsing experience. It does this through an internet cookie. Imagine that you visit a shop in real life. When you enter the shop, the security guard takes a photo of you and gives you an ID card (the cookie). As you browse the shop, the store cameras can keep a record of what you looked at, which areas of the shop you spent time at, etc. All of this info is recorded onto your ID card. When you leave the shop, you get to keep your ID card with you. When you visit the shop again, the security guard sees your ID card and lets you through without any further questions (i.e. staying logged-in to a website when you come back to it) and the store knows what you did last time so they can bring that back up if they wanted to. What if the store is shady? They might sell copies of your ID card to their little ring of shady businesses and all of a sudden you get a bunch of spam in your mailbox from these unwanted folks."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2wh39
|
what is allowing us to fit more information into smaller spaces as technology advances? How can a microchip achieve what a room full of computers couldn’t 30 years ago?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnnxraa"
],
"text": [
"At the lowest level, a computers memory is made up of bits, which are little things that can represent either 1 or 0-on or off. The very simple answer is that we’ve been able to gradually find new ways to make those representations smaller and smaller."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g2yk5g
|
Why do Wi-Fi and Bluetooth need my location?
|
I am concerned about my privacy and have turned on location only for essential services. Can I safely turn off networking and wireless in location services?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fno9b44"
],
"text": [
"If I remember correctly, it's because the SSID's (The name/fingerprint) of WiFi and Bluetooth can be used to figure out your location anyway [Yeeeee]( URL_0 )"
],
"score": [
3
],
"text_urls": [
[
"https://forums.developer.apple.com/thread/123342"
]
]
}
|
[
"url"
] |
[
"url"
] |
g31qxr
|
In programming, why do bygs or glitches only occur some of the time as opposed to all of the time?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnoo3am",
"fnotkgg"
],
"text": [
"Bugs/glitches happen because a bunch of variables and situations line up in just the right (or wrong) way, so in a very complicated program, there may be variables that aren't immediately apparent to the user, things that are kept track of and used in calculations, but aren't explicitly told to the user, so while all the variables the user can see may be the same, these unseen variables may be different, thus creating different results. Also when a bug is easily repeatable, it tends to be easy to figure out the root of the problem and fix it, hope this helped.",
"Simply put, the vast majority of the time, a bug is something unintentional caused by oversight or laziness of the programmer, not a fault of the computer itself. We do our best to make stable code, and then usually the resulting program is run through quality control testing, where we go back and forth fixing things that get caught before we release it. But some obscure things will just slip through the cracks and can only be found by the massive amount of users with vastly different scenarios, such as location, hardware, combination of profile settings, etc."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g32xse
|
So what is the difference between Cloud and Edge computing? Actually, what IS Edge computing in concrete terms?
|
Been trying to wrap my head around it, read different articles but it sounds so vague to me.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnouwkd"
],
"text": [
"Edge computing is data-driven computing that is done near the source of the data. For instance, a Street Light will have a sensor that determines the light level, but will also take into consideration things like the time of day and day of year to determine whether or not it should turn on. It does this in a computer in the street light rather than send all the information back to a city server to make that decision. Cloud computing is on-demand computing power. Cloud providers like Amazon, Microsoft, or Google have datacenters of servers waiting to be used in on-demand roles, whether that is spinning up new Virtual Machines, running non-persistent programs, data storage, or so much more. The key factor is that you can actually programatically buy server space, so your application can actually get the resources it needs to run."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g35r9y
|
Why do video games tend to require a loading screen when you walk into a building? I’m thinking about games like Skyrim which let you roam their huge open world without any loading but require a load screen to enter a small building.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnpc2k9",
"fnpk5l6",
"fnpr6z2",
"fnphwmp"
],
"text": [
"A couple possibilities come into mind. First, towns tend to be a lot more dense. That is, there's a bunch of stuff in a relatively small space. If all the interiors of all the buildings had to be rendered when you enter the city, it may exceed the ability of many systems to render well. So to mitigate this, the game waits until the player enters a building before rendering it. Another possible reason is simply to allow more modular programming. The interior of the building doesn't have to exactly match the outside dimensions, allowing the developers a little more room to make elaborate interiors without worrying that they might infringe on the constraints imposed by the exterior. So you can have one map designer working on the overall layout of the town while another works on the interiors without worrying about potential conflict.",
"Depends on the game. Some games, like World of Warcraft, stream assets in all the time. As you walk, the game unloads things far away and loads things you're moving towards. This is nice, but harder to develop and requires some spare processing power and memory. Some older consoles just don't have the capacity. Some games, like, say, Final Fantasy 12, just *don't* implement dynamic loading due their target hardware. FF12 was originally made for the PS2, which doesn't have as much RAM as a modern computer. The recent Steam release of FF12 makes the small zones seem laughable in the face of what a game like Doom Eternal considers a single zone. FF12 was probably a fantastic experience when it was first released but now the small zones may seem awkward, as walking from one town to the other consists of relatively small areas with a loading screen between each. Back to World of Warcraft, you can walk across an entire continent with no loading screen but if you get teleported/summoned, you hit a loading screen. Why? Dynamic loading takes time. It has to take some time to pre-load things near you to set the system up, as well as unload things farther away (which, admittedly, is far quicker a process).",
"In the case of Skyrim their loading system is tied to cells. A cell in the engine Skyrim uses is a certain size, and when you enter that cell everything in it is loaded into memory. They don't just load the cell you are in, they also load a certain number of cells around the cell you are in. Outside this load distance they switch to lower level of detail objects to save on memory and rendering time. The benefit of this is that you always know exactly what is loaded in, and it's easy for a developer to understand it because it based on defined spaces. The downside is that the game will load data you might never see. Let's say you enter a cell that has a giant wall down the middle of it. You can never see what's on the other side of the wall or go over there, but there's a bunch of assets over there. Because they are in the same cell as the player they are loaded into memory even though it's impposible for the player to see it. A lot of memory is used on things the player can never see. Because of this they put buildings into their own cells. When you use a door or cave that uses a loading screen you are going into a completely different cell that only has the interior loaded. This means they are not using memory to load the interiors of buildings unless they have to. Other games use a somewhat more dynamic loading system. In Assassin's Creed: Odyssey if you enter a cave you don't have a loading screen, but you might notice that caves all look very similar and simple. They do this to help save on memory as you enter the cave. Further into the cave suddenly you might find lots of unique props. They are using that entrance to the cave to give the game time to unload parts of the world outside and load the next part of the cave. If you walk backwards in a cave and look out the mouth of the cave you'll see a point where suddenly it goes really bright and you can't see anything outside. This is where they are unloading the outside world. You can find open interiors of buildings, but they are rather some in design and assets. If you pay real close attention you'll notice many buildings with interiors are set away from other buildings, or have large open areas around them compared to buildings that don't have an interior. This might be how they ensure there's enough free memory for the extra assets needed for building interiors. Ubisoft doesn't provide any information on how the loading system works unfortunantly, so we can only determine what's going on by looking at locations in game. For linear games there's all sorts of tricks to mask loading time. One of the more commons ones is slowing the player down so the game has time to load. This might mean the player character litterally slows down to very slow walking speed (Arkham Asylum loved doing this, and put Batman on his radio so it seemed like he was really listening). More recently games have been forcing player characters to crawl very slowly through narrow spaces, which masks a load. Tomb Raider loves using this one.",
"This makes me want to ask a similar question, why is it that in some games, when I die loading takes as long as if I just opened the game and loaded that file? At times the save was literally 5 feet from where I died"
],
"score": [
60,
24,
15,
5
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g361zq
|
why does the web browser start off with about:blank when opening a new link
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnpdcro",
"fnpp50b"
],
"text": [
"By default, that's the browser's page (one of many). It's content can vary based on the browser, but they usually contain a search bar to make it easy directly search for something. This can be changed to something else in settings or with custom start page extensions.",
"If you're talking about seeing about:blank when you click a link to open it in a new tab, then like others have said, the browser is creating a blank page first thing. It likely does this because it hasn't resolved the hostname yet. In a more ELI5 manner, the browser doesn't have the website itself to show you yet, so its got a blank page ready for when it does."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g36ycv
|
How are successive generations of data standards (USB, HDMI etc.) able to pack more features (data speed, quality etc.) into the same form factor ?
|
For example, HDMI generations appear to have the same connector, yet the new generation has more features than the older one.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnpjhsx",
"fnpwx9f",
"fnpryl1",
"fnpx0rx"
],
"text": [
"They key is almost always that they become more able to put the same amount of data in a smaller physical space, either die to precision in reading or writing mechanisms. Imagine taking a 1st grader and having them write out a whole page about their day. Their writing will be rather large, so the amount of information they put in there will be limited. Ask someone in college to do the same task and they will be able to write cleaner and more precisely, allowing them to actually put more information on the page. The same is true with most evolving standards. They can either write or read more precisely (or both), allowing them to do things like send signals in shorter pulses, which allows for more data over the same time.",
"Lots of complicated reasons. For one, as technology improves, we can send the zeros and ones across the wire faster and faster. Since our processors have gotten so fast, they're able to read signals off the wire faster than previous generations. To put this into perspective, one of the most widely used serial protocols is RS232. The fastest official transfer rate is 19,200bit/s. The ethernet hardware in your PC is most likely capable of 1,000,000,000bit/s, and even then that's an old standard that's pretty slow. New standards are ten times faster. Raw processing speed isn't enough though. As signals on the wire get faster, weird things happen. The signal is strongly affected by outside interference, and sometimes it even interferes *with itself*. To combat this, we develop new cable technologies, either shielded copper, or fiber optics. But that's still not enough, we sometimes need special hardware to clean up the signal and extract the data from the noise. These are very specialized computer chips designed specifically to deal with noisy signals. This technology is still relatively new, and improving rapidly. On top of all that, we keep just simply adding more wires. For instance, USB1 and 2 use a single twisted pair for data. Basically, one data connection shared between upload and download (that's why it's called universal *serial* bus). USB3, on the other hand, adds two *more* data lines, tripling the total amount of data one cable can carry. To even further increase data transfer rates, some systems use compression. Since processors are so fast now, it actually makes a lot of sense to compress data before it goes on the wire, and decompress it on the other side. Generally speaking, the slowest part of your system is going to be data transfer. If you can reduce the total amount of data you put on the wire, you reduce time spent waiting for the transfer to finish. These data transfer technologies have a lot of components, but each one is improving independently! With each generation, most or all of the components involved has improved, which tends to result in massive gains when it's all put together!",
"Faster chips handling the communication at each end. Same way that a network cable tends to work at whatever speed you want, depending on what network card/port is at both ends of it. It's just a cable in between, it's how much data you can process, compress, etc. and send over it, and how sensitive and quick the sensors at both ends (e.g. TV and laptop) are at converting and interpreting the signal that the other side is sending.",
"Data speed and quality are most commonly related to more advanced encoding techniques. The fundamental issue is one of noise. If you're willing to transmit slowly enough over a robust channel, you can virtually eliminate noise from consideration. But as you start to transmit more quickly, noise - and accommodating it - becomes a major factor. The original mechanism for dealing with this sort of issue was a simple parity check. You count up all the high signal values. If it's even, you have one parity. If it's odd, you have the other. So if there's a single bit error, you'll be able to detect it. However, if there are two bit errors, then you won't. More advanced codes based on Shannon's Limit and the Hamming weight (I include these terms without definition if you want to Google-fu a more comprehensive answer) significantly increase your capabilities. These allow not only detecting but repairing errors up to a certain limit. As your encoding becomes more sophisticated, you can push the envelope on noise pretty far. Depending on how much latency you can tolerate (how large your encoding blocks are), you can create some fairly robust transmissions over channels being run at speeds which incur noise that would be unacceptable with less sophisticated encoding. Note that hardware has almost nothing to do with this. While the hardware will be insufficient to run some of these encoding techniques if you go back far enough, the frequency limits on hardware have remained relatively unchanged for decades. More sophisticated processing also isn't relevant because these encoding techniques are normally run in dedicated firmware. Similarly, the physical cabling has remained relatively unchanged over the same time span. The answer really boils down to 'better math'."
],
"score": [
16,
6,
5,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g38gxm
|
What is an API call?
|
I am not a programmer by any means but my boss keeps mentioning API calls in his conversations with me. He’s even explained it twice and I just don’t understand anything he’s saying lol.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnpvu0q"
],
"text": [
"ELI-a-non-programmer: An API is like ordering from a takeout restaurant. You know the number you need to call, you know what you need to say, and you know they'll give you something in return. What you *don't* know is the inner workings of their kitchen, on how they prepared that food for you. An API is similar: you have somewhere to make the calls to (usually a URL, like a web address, but not necessarily), you have a specific statement you make in order to get something back (\"I'll take a large beef and brocolli\", \"send me a list of all customers who have ordered in the last month\", etc), and without you knowing *how* it's doing that, it sends you the requested information back. Why are these important? Because they allow you to use a service without being hooked into the details. For example, making calls to a weather API can tell you what the weather's like in a particular zip code, without you actually ever having access to any of the weather sensors they use to determine that."
],
"score": [
24
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g3bwr3
|
Why don’t we use atmospheric water generators to solve the water crisis literally everywhere in the world?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnqd0t0",
"fnqlbgr",
"fnqd7fu"
],
"text": [
"Building such an infrastructure would be unfathomably expensive and take incredible amounts of energy in order to run it.",
"The other concern here is that the places that need water the most are in very dry areas like deserts. Those places are dry because there is no moisture in the air to make rain. So, there would be no humidity in the air from which to reclaim water. The places that need it can't really make it, so then we would be talking about transporting water from places that could make it to places that need it, which we already have a problem with because of lots of considerations noted by other comments. There's limited success with this tactic on the fringe areas of deserts, tho. The Atacama desert is one of the driest places on earth because the humid air from the Pacific has to drop all it's moisture as snow in the Andes before it can go inland - leaving no moisture for the desert. Chile is harvesting water from the air in an effort to provide water to the desert.",
"Cost of building, cost of transporting the water, cost of the power requirements... there is an endless list of reasons that would make it unfeasible."
],
"score": [
12,
6,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3c5dm
|
Why are songs on public radio with lyrics like "bangin on the bathroom floor" heavily censored in today's society when there are games and shows showing explicit nudity and not nearly as censored?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnqf8qh",
"fnqg6u6",
"fnqgwss"
],
"text": [
"Radio broadcasts are designed for everyone, including children. Videogames with nudity are rated M for Mature and theoretically only sold to adults.",
"Not an explanation, but rather a clarification: lyrics aren’t censored everywhere. Over here in Europe, for example, we don’t beep out, silence, replace, or otherwise censor music in any way. The same goes for swear words on television: you can still say ‘fuck’ or ‘shit’ or ‘God damn’ on television. Bad language is simply considered normal (which it is). As long as it doesn’t break any laws (eg. racism), it’s okay.",
"FCC regulations. Things that are publicly broadcast (such as radio or tv channels you can recieve with an antenna) are subject to regulations by the government on what they can broadcast. Whereas movies, video games, music, and cable are free to do as they wish since you have to pay for them. That being said many cable channels or record labels may voluntarily choose to censor things out of fear of complaints or loss of funding from advertising."
],
"score": [
9,
6,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3cpmr
|
how does a handheld device/laptop switch itself off after you tell it to?
|
when you go to your menu and select "shut down", i don't get what the device does to shut itself down, it's not like you're pressing the power button to turn it off thereby cutting off the energy source to it, you're giving it a command that it then follows, and it makes itself unable to be used until the next time its switched on, how exactly does this work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnqiyp3"
],
"text": [
"The button triggers a rundown code that shuts down the system. Your phone has an internal power system even when its off, so pressing the button to turn it on triggers the power cycle and it boots"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g3j929
|
Why do they put the power lines above ground instead of underground like internet cables, or in a sewer-like setting where they would still be protected and accessible but wouldn’t be a constant safety hazard?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnrm93l",
"fnrm6o1"
],
"text": [
"Power lines are largely underground in areas where people are living/working. Outside of these areas where a power line isn’t too much of an eyesore it’s just massively cheaper and easier to build and maintain lines above ground. If put underground miles upon miles of excavation would need to be done, and maintenance would be much harder and much slower. In rural areas and roads its much easier to just throw up a pole or tower and string lines along. Also, I’m guessing, earthquakes would cause a lot of trouble with long underground lines without much slack in them.",
"It's waaaay cheaper than burying thousands of miles of cable, and cables in the air are lighter and cheaper than the insulated underground ones. And it's really not much of a safety hazard unless you're climbing utility poles regularly. Maintenance is also a lot cheaper and easier."
],
"score": [
7,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3kdf5
|
How is data recovered from formatted hard drives/partitions?
|
I just don't see how this is possible if it's relatively easy to do with software.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnrsrbx",
"fnrvogd",
"fnrsvnu"
],
"text": [
"So data on a computer is a bunch of switches that are either on or off. To keep track of those switches, your device has a directory of what switches correspond to what data. To save time whenever you delete something your computer doesn't go and change all those switches that represent the data to off. Instead, it goes to the directory for those switches and changes that to THERE'S NOTHING HERE But those switches are still there, unchanged. Your data is still somewhere, your computer just lost track of it in the directory.",
"The other answers only deal with deleted files, not reformatted drives you asked about. A quick format just deletes the file directories so the data is still there, but if you do a full format it rewrites all the disk surface so old data is unrecoverable by the OS. However forensic techniques can read the residual magnetization that hasn't been fully randomised, particularly at the edges of the tracks where the drive head doesn't *exactly* pass over the same line every time. That's why some security programs write and rewrite over the same disk area multiple times to make sure data can't be recovered.",
"A hard drive is full og 0's and 1's when you delete something from your hard drive it's just told that the part that kept your data can be overwritten, it's not reset unless you force clean it (lookup free whitespace) That means unless you keep filling your drive with data, you can still recover lost files. As the only thing lost is the file pointer not the data"
],
"score": [
12,
7,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g3o1w8
|
What’s the difference between a notebook and an ultrabook?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnsdqjh",
"fnse2md"
],
"text": [
"It's just marketing names for a laptop that has above-average parts, like CPUs with many cores, graphics cards that can play high-end games, etc. If you paid more than $1,000 or $1,200 USD for a laptop because of its specifications, it's probably fair to call it an ultrabook.",
"They're the same performance wise, but the Ultrabook is lighter, thinner, and more expensive."
],
"score": [
10,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3p25m
|
If we've definitely run out of IPv4 addresses, how is the internet still able to function properly and let more people sign up if not every website and user has switched to IPv6?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnsof31"
],
"text": [
"When IPv4 was first created, every device would be given a unique address and be able to reach any other device around the world. Realizing the problem after multiple companies started buying hundreds of IPv4 space for their business needs. Engineers created a clever way of reusing the IPv4 address on the public internet and using a private IPv4 address for all the computers inside the company. NAT and PAT allowed any number of your private IPv4s to use the same IPv4 on the internet. This change effectively saved the world from running out [already]. Though, it is still limited and there's IP blocks that are assigned and sold from a few IP companies. Consumers shouldn't ever worry as the ISP will have a list of available IPs to give for quite a while. Edit: [Wiki: IPv4 Address Exhaustion]( URL_0 ) > On 31 January 2011, the last two unreserved IANA /8 address blocks were allocated to APNIC according to RIR request procedures. Blocks of IPv4 space are bought in a hierarchical manner, and multiple IPv4s are available from ISPs as they recycle their current IPv4 allocations. The IPv6 has seen greater reception, now that IPv4 is exhausted. Note: IPv4 and IPv6 can work together with translators. This allows your IPv4 computer to reach IPv6 services, and vice-versa."
],
"score": [
4
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/IPv4_address_exhaustion"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3rmdn
|
How can robots not beat captchas when some are as simple as clicking a button?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnt12np",
"fnt0kc1"
],
"text": [
"The button clicking captcha is deceptively complex. It's really a masterpiece of design to be so simple for a human and yet still be effective. With the button clicking captcha you've already 90% passed the test before you ever see the button. They've looked at the various metadata that your computer sends, like what your browser is, and seen that it matches patterns associated with real people. They've seen that this is the first request from your IP address, or perhaps they check that you're logging in from an IP address that's already associated with the account you're logging into. By the time you see the button they're already pretty sure you're a human. Then you click the button, but it's not just a click. They watch your mouse motion. They check to see if the mouse jumped straight to the button and issued a click event. They check to see if the mouse moved in a perfectly straight line, or with other improbable uniformity. Ultimately the button clicking itself isn't that hard to design a robot to beat, but it would take some time. Once you perfect the button clicking robot and start using it you start failing all the checks that led to you getting the button clicking problem in the first place. Perhaps you make a simplified web browser that doesn't register properly as being Chrome/Firefox/IE/whatever. Perhaps you make too many requests in a short period. Perhaps you try too many times to log into accounts that don't actually exist. You quickly wind up flagged as probably a bot, so you get sent to the \"hard\" captcha like image labeling. Image recognition is one of those fun problems where the software to do it is increasingly well understood (it's an active area of research, but computers have been out-performing humans for several years now). The challenge in making an image labeling program is that you need a lot of human-labeled data to train it off of. It's costly and time-consuming to gather that data (which is the other service that companies like recaptcha offer—they're using your clicks to help big companies train machine learning algorithms for tasks like self driving cars). In the end the process for developing a bot to defeat captchas is straightforward enough, but the effort it would take to do so is greater than the effort it would take to just hire a bunch of people to solve the captchas for you. That's the threshold for \"good enough\" for a captcha.",
"it’s something to do with not how you click the button, but how you move the cursor and how quickly you click the button. a robot would move the cursor immediately, in a completely straight line, and quickly click the captcha. whereas with humans, there’s a slight delay and an wobbly line"
],
"score": [
25,
9
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3rprp
|
Why does it seem that computer hardware is not as advanced as software?
|
For example is playing a video game that requires high end pc parts but are still somehow unable to perform without heating up due to said video game?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnt5tg1",
"fnt0v3z",
"fnt6jf1",
"fntdrc3",
"fnt7rw7"
],
"text": [
"What's 5 times 5? How long did it take you to answer that question? Okay, now tell me, what's 55555 times 55555? How long did it take you to answer THAT question? Both are about the same level of effort for me to ask you, but one takes a lot more time to answer. Computers on the most fundamental level are just machines that do math. More detailed graphics mean your computer has to solve more math problems (or more complex math problems) in the same amount of time. It is pretty easy to scale software demands upon hardware to increase resolution, but it's not very easy to practically scale up hardware.",
"Hardware is just as advanced, just not as cheaply available. The cost to create 100 copies of software is the same as 1,000,000. That is not true for hardware. So...if you want great hardware it's going to cost more because it has more expensive manufacturing processes, materials, or simply more parts (multiple drives, cpus, more ram, etc.). And...heating up by itself is not bad, only if beyond what is safe for a given setup.",
"Without the hardware, software would be meaningless. More than anything, it is because of our hardware advancements that software is able to continue to develop more complex things.",
"Hardware it's definitely advancing, I think you would agree. If you play old games on modern hardware, they run with no problem (except possibly due to incompatibilities). We actually have to add artificial slowness to very old games, because they were designed to run all-out on old hardware just to keep up, and now they go too fast to be playable. What you're seeing is that running modern game software on modern hardware it's taxing. But that to be expected — the developer *purposefully* designed that software to run at the edge of what the hardware can handle to make as impressive a game as possible. So it's not really a fair comparison. You're looking at an Olympic athlete running a marathon and saying, \"Why are they winded? They're supposed to be the best!\"",
"Hardware is limited by actual physical limitations. You can only make a transistor so small before you run into problems. Software is only limited by imagination, and of course also hardware that can actually run it. As for heat, you will always get heat, according to the law of thermodynamics. You can't have a 100% efficient CPU."
],
"score": [
12,
6,
5,
5,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g3ueic
|
what’s the difference between a Cochlear Implant and a Hearing aid?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnthnod",
"fnuy9vt"
],
"text": [
"Answer: A hearing aid is like a little megaphone that goes into your ear, it picks up sound, amplifies it, and plays it directly into the eardrum. A cochlear implant bypasses the ear altogether and directly stimulates the nervous system, it’s essentially a prosthetic ear.",
"A hearing aid makes sound louder. It is used by people who can still hear, but not very well. A cochlear implant is for people who are completely deaf. Instead of amplifying and replaying the sound, it converts the sound into an electric signal, and sends that signal directly to the nerves inside the ear (the cochlea). This way, if your ear is damaged and doesn't work at all, you can still hear using the implant as your \"ear\". An analogy for vision would be as follows: Hearing aids are like glasses. Glasses help a person with bad vision see more clearly. Cochlear implants are like artificial eyes. Even if your eyes are completely blind or are missing, artificial eyes would still allow you to see."
],
"score": [
12,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3urbq
|
Why does rotating, or removing and then returning the same batteries, suddenly make them work again?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fntk6y1"
],
"text": [
"It wipes the dirt off the ends of the battery, reducing that resistance."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3vxub
|
In journalism, when reporters are trying to dig up old footage for a story, how do they draw it up so fast?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnts1rd"
],
"text": [
"In some cases, what you're seeing is a pre-packaged piece of footage, kept around for quick access. For example, if a famous celebrity dies, journalists will not be putting together a video package from scratch. Rather, they'll grab the package of footage that was already created and ready to go, prepared in advance for precisely this moment. This kind of preparation can also be focused on a *general* *topic*, instead of a specific person, thing or event. \"Get me a package of footage showing people lining up to vote outside a polling place,\" for example, in a story about voting rights. Archival footage will be archived with metadata -- a transcript or notes about what's in the footage. That metadata is searchable, which gives them a lead to review the footage in more detail and decide how to use it."
],
"score": [
13
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g3zprs
|
How do long (8 hr+) exposures of the night sky work?
|
I keep seeing these amazing photographs of nebulae and the milky way being described as many hour long exposures but there are stars in the images that are not streaking across the sky. The Earth rotates in that period of time. How do these long exposures work? Are the cameras moving to compensate for motion of the Earth?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnuicqx",
"fnuji5w"
],
"text": [
"The cameras are turning, yes. There are computer controlled mounts that will turn to compensate the Earth's rotation. Sometimes the pictures are taken over multiple nights as well - they will be collecting light over night but shut/off in the daytime. Edit: There are some gorgeous videos from cameras on these mounts. They can take a time lapse of multiple-second exposure images (to make the Galaxy brighter) and stitch them together into a video. Here's a video so you can see better how these camera mounts work URL_0",
"Yes you need to rotate the camera. The simple way to do that with a [Equatorial\\_mount]( URL_1 ). You the telescope mount so one axis is parallel to the axis or earth by pointing it to the polestar. You then rotate the telescope around that axis at the same rate earth rotate and you can look through the telescope at the same star as long it is above the horizon. The rotational speed is not once per 24 hours but one per 23 hours, 56 minutes, 4.0905 seconds. The difference from 24 hours is from earth rotation around the sun 24\\*60/ 365.256 = 3.9424 minutes. An orbit is 365.256 days. The 0.256 part adds up to one day per 4 years ie the leap day. There is more about an equatorial mound [here]( URL_0 ) . The first one was rotated by a mechanical system like a clock and later used just electrical motor as the constant speed with gearing. No complex console is needed for it to work. The mounts today used a computer but it is not required.. Today you do not take a single 8-hour exposure but multiple shorters and stack them on a computer. There can be clouds, airplanes, birds, etc that destroy a shoot. So you might take 48 ten minutes exposures for a total of 8 hours."
],
"score": [
11,
3
],
"text_urls": [
[
"https://youtu.be/1zJ9FnQXmJI"
],
[
"https://www.spaceoddities.eu/2018/08/astrophotography-what-is-an-equatorial-mount-and-how-does-it-work/",
"https://en.wikipedia.org/wiki/Equatorial_mount"
]
]
}
|
[
"url"
] |
[
"url"
] |
g41ybn
|
what does working close to the metal mean?
|
I was watching this tv show called halt and catch fire and someone said “have you ever worked close to the metal?” What the heck does that mean in programming?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnuyvu2"
],
"text": [
"**Edit: realized my original answer was more of ELI20, here's my proper ELI5 answer:** It means using a language that's easy for computers to understand, and they can use it really quickly. The saying comes from it being closer to the instructions that the computer uses directly in its processor, the \"metal\". These languages are really hard for people to write or understand though, so not used very often. Languages that are easier for humans to understand and write but harder for computers to understand are likewise \"farther\" from the \"metal\", the computers need to do more work to understand those languages, so it's not as fast. **For those interested in more details, here's the original ELI20, and a computer science student answer:** It means using a programming language with fewer layers of abstraction, closer to the raw machine code that is running on the \"bare metal\". This is also often called a low-level language, pretty much synonymous with a language being close to the bare metal. Writing assembly is very close to the metal, so can run very fast, but also really hard for humans to write, so more often we use languages that are built atop that, farther from the bare metal. Meanwhile a higher level language like Python is much farther from the metal, but therefore is able to be designed to be much easier and more intuitive for people to learn and use. An intermediary level is C, which is still pretty close to the metal, but does have most of the features people typically expect from a programming language, such as functions and loop constructs. So it's harder to use than python, but slower than pure assembly (though modern compilers and optimizers can get pretty close, enough that almost nothing other than the minimum needed is actually written in assembly anymore)."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g41yfz
|
if an internet speed test is recording 1gb download speeds, why when you download something that’s 20gbs doesn’t it take only 20 seconds
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnuwd4c",
"fnuweio",
"fnvbh3f"
],
"text": [
"Couple reasons - giga*bit* does not equal giba*byte*. A byte is eight bits. Also, your hard drive or solid state drive probably isn't capable of writing that information fast enough. At most the drive might only be capable of saving the information half as fast as it's trying to be downloaded. When you run a speed test you aren't actually saving anything to the computer, so you get pure internet speed. When you download a file it needs to be saved, and it is \"bottle necked\" by the write speed of whatever you're saving it to.",
"1gbps means 1 giga**bits** per second. There are 8 bits in a byte. To work out the potential speed of a 1gbps connection, you need to divide it by 8. 1gbps = 1000mbps. 1000mbps / 8 = 125 Megabytes per second. a 20 GB file downloading at 1 gbps (or 125 MB/sec) should take around 2.667 minutes to download.",
"I think you've got your answer on the direct cause of the thing you're asking about, but I'd like to explain a little bit of why these units are the way they are. When you send data over a serial connection, as is the case with older standards of Ethernet (the cable that \"internet\" \"comes from\") or USB (it's what the S stands for), every bit needs to be sent one bleep and bloop at a time. That is why they are called *serial* connections, because they happen in a *series*. A single-file line, basically. Since all the bits are coming through one pipe, and the pipe itself doesn't really care what kind of data is coming through -- it could be a file, or 10 files, or half a file, or a raw data stream, or garbage, or whatever -- it's much more useful to talk about data throughput in terms of how many individual bits can make it through per unit time. Hence, network throughput speeds are typically measured in bits per second. Standard SI (metric) prefixes can be added to bundle the units into powers of 10, which is where we get kilobits per second (Kbps), megabits per second (Mbps), gigabits per second (Gbps), and so on. Once that data is written to disk on a computer, now we have to treat it a little differently. Computers don't read bits one at a time like serial connections do. The smallest unit of data a computer can deal with is dependent on the size of the memory registers in its processor, which are more or less where a processor is able to put data \"in its head\" while it's doing a calculation. (If you've ever heard of \"8-bit\" or \"16-bit\" video games, or \"32-bit\" vs \"64-bit\" programs on PCs, this is exactly what they're talking about. It's the register size.) This wasn't always the case, but today, most computers have register sizes in multiples of 8 bits. So when talking about things that make sense in the context of data on a computer (like files), it's much more useful to measure their size in bundles of 8 bits, or *bytes*, since that's the smallest unit of data we'll ever be working with directly. Again, you can combine these with the SI prefixes to get kilobytes (KB), megabytes (MB), gigabytes (GB), etc. Further sidenote: since computers are inherently binary systems, it's much more elegant to do work purely in powers of 2 instead of powers of 10. So when computers do things like reserve memory, they like to do it in chunks that are powers of 2. Say you wanted to store a kilobyte of memory. That's 1000 bytes. But 1000 isn't a clean power of 2. But 1024, a number that's kind of close, is! So the computer may allocate a 1024-byte block, fill it with that kilobyte of data, and leave the extra 24 bytes unused. This can be kind of wasteful. So some applications have decided to stop using SI prefixes for byte sizes and instead invented binary counterparts. Instead of kilo-, mega-, and giga-, they use kibi-, mebi-, and gibi-, giving us kibibytes (KiB), mebibytes (MiB), and gibibytes (GiB). Instead of being steps of 1000 from each other, they are steps of 1024. This leads to the awkward situation where one **gibi**byte is equal to something like ~1.0737 **giga**bytes. The very irritating thing about the kilo/kibi twist is that most systems (like Windows) report data size on disk in \"kilobytes\", etc, but are actually reporting *kibibytes*, etc. Presumably because the concept of a \"kibibyte\" was exactly what they needed when working on their systems, but the term itself wasn't in widespread use and they didn't want to confuse people with funny units. So, to tie back into your question, most of your delay in downloading a 20 GB file over a 20 Gbps connection is, as the other commenters say, due to the units being confusingly similar, but different -- the file is actually eight times larger than the data throughput. But a small fraction of it is probably due to a second confusion of units -- your computer is lying to you by calling it 20 GB, and the file you're transferring is actually 20 G**i**B in size, which is about 7% more bits over the wire ."
],
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23,
4,
3
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|
[
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[
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|
g42o6d
|
Why do most TV remotes still use infrared instead of bluetooth?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnv12fs",
"fnv1rd0"
],
"text": [
"IR is cheaper to produce. Especially since the manufacturing process is already set up for it.",
"As others have said IR is cheaper. Bluetooth also can have some interference problems with wifi. I have a pair of Bluetooth headphones that cause the wifi on my laptop to drop in and out."
],
"score": [
11,
6
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|
[
"url"
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[
"url"
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|
g44gmj
|
how does a guided infrared missile lock onto it's target?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnvbdq6"
],
"text": [
"It has a sensor that looks for heat sources, basically. When it finds one, it adjusts the wings on the missile to go in that direction. Since the jet engine of an airplane produces a lot of heat at the exhaust, that will generally be the biggest source of heat it picks up. This is also the reason some planes can release burning magnesium flares- to generate additional sources of heat, sometimes hotter than the jet exhaust, to try and let the sensor lock on to them, away from the plane."
],
"score": [
4
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
g46kb0
|
Pointers in C
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnvmtbk",
"fnvoc4y"
],
"text": [
"Think that you have a lot of shelves and put things on the shelves. Sometimes you want to remember where you a certain item, so you get a sticky note and write the location of that thing. Now you don't have to bring that item every time you want to give it to someone. You can just give the sticky note to the other person and he can go bring it on his own.",
"Pointers are like item-specific sticky notes than you can use to communicate with other people (or other parts of your program). These notes can tell you where to find all sorts of things but they don't *have* to; sometimes they may give you a false address (either because the thing they're pointing to has moved to a different address or because it doesn't exist anymore), or not give you an address at all. Even if there's no address on the note, however, you can still tell what item they're supposed to be pointing to by looking at their type. Let's say you bake a cake and put it on the kitchen counter (`cake my_cake = make_cake(\"chocolate\", \"kitchen counter\");`). You take a sticky note that's reserved only for cakes and write \"There's a cake on the kitchen counter\" on it (`cake* pointer_to_my_cake = & my_cake;`). You then stick the note on the living room sofa, so that your housemates can see it and find the cake while you go take a nap. Your first housemate, John, finds the note and follows its directions to find the cake on the kitchen counter. He's a greedy a-hole though, so he takes the entire cake with him back to his room and eats half of it. Your other housemate, Joanne, sees the note a few minutes later and also goes to the kitchen, but doesn't find anything on the kitchen counter. She followed a pointer that had been invalidated, i.e. didn't point in the right location of the cake (either because it had moved or because it didn't exist anymore). She then goes back to her room and writes a post on Facebook saying how some people *\\*cough cough\\** are greedy a-holes. John sees the post and feels bad about what he did, so he leaves the rest of the cake on a table in the hallway. He then goes to the living room and updates the address on the note to be the hallway table. Joanne then sees the updated address, finds whatever is left of the cake and eats it all because she's angry at John. You finally wake up from your nap feeling hungry, so you go to the living room and see that the note now says \"There's a cake on the ~~kitchen counter~~ hallway table\". You follow the note and go to the hallway table, but you find nothing because there's no cake anymore. You angrily go back to the living room and scratch off the last address too, leaving only \"There's a cake\" written on the note (`cake* pointer_to_my_cake = nullptr;`). You go back to your room and you start searching for a new flat."
],
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21,
6
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[
"url"
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[
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|
g481lo
|
Advanced Data Structures (Binary Trees, Hash Tables, Linked Lists)
|
Recently, I’ve been really wanted to get into programming. I know the fundamentals and have a very basic understanding of these data structures but really would like to have a better understanding or their purposes/how they work. Thanks in advance if anyone sees this!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnvvtmo",
"fnvwsh1",
"fnwim0l"
],
"text": [
"The most simple data structure is a standard array, which it’s simplicity can be great for a lot of tasks! But when when you need a more purpose driven task, advanced data structures can work even better. Hash tables are my favorite, and have a lot of applications, but the main purpose is to efficiently find an element in the list. It’s sort of like a library bookshelf. If you tried to find a book thats organized like an array, you’d have a long list of titles, you’d start at the beginning of the bookshelf, and search one by one until you found the book you were looking for. A hash table instead is like the Dewey dot system, where each book has a unique number assigned to it. This number is assigned by taking the title of the book, and running it through a formula to determine its position on the bookshelf. When you want to find a book, you’d enter the book title into the formula, and it’ll spit out its exact position on the bookshelf, and you can go right to it without having to spend any time searching! Linked lists are great because they can shrink and grow at any time. An arrays size is determined and static when you create it, a linked lists size isn’t static. This is a lot more memory efficient, because you only use what you need! Binary trees are really a family of data structures, rather than just one, and are great when your application naturally flows like a tree with branches! It usually provides the a very efficient path, such as a binary search tree, which is an efficient way to find an element in an array",
"Linked List: You can think of a linked list as a conga line of people, and each person is an entry in the list. Let's say you want to find someone named Bob in the conga line, you would start at the front and ask if their name is Bob, and if not, you follow the arms to the next person and then ask them their name. In the data structure, each person is called \"a node\" who really only keeps track of their name and whose arms are on their shoulders, the first person in the list is usually called \"the head\" and the last person is called \"the tail\" Hash Tables: Imagine a town where you are the postman, each day you get letters to deliver to the residents. Your problem is that although the houses have addresses, each labeled with a number, the letters do not. The letters all just have the name of the person who is supposed to get the letter. To let you find where to put all the letters, the mayor has come up with an ingenious plan: come up with a formula that spits out a number when given a name, and then move everyone into the house whose number corresponds to their name when put through the formula. Now to deliver messages, all you have to do is type the name into something that computes the formula based on the name, and it'll tell you the address that person lives at. In this example, the houses are the indices of an array, and the formula is something called \"a hash formula\" which is really any formula that converts some amount of data into a number.",
"An array is a contiguous block of memory that you will want to use my time you know how many elements you will hold. If you are unsure, you may either end up allocating too much space (overestimate) or needing to resize (underestimate) which is a very costly operation since you will need to copy all of your data to the new memory space. Alternatively, if you need random access to elements in a list and will not write often, an array is a viable data structure for that task. Linked lists attempt to fix this issue by separating each piece of data into its own discrete node. Now, the only memory that needs to be contiguous is the node, rather than the whole list. However, since the nodes are spread all across memory, each node needs to know where the next or previous node in the list is. By asking each node where the next node is, you can traverse the whole list just like an array. Additionally, it is very quick to insert a node in-between two other nodes in a linked list by modifying where they point or refer to; in an array you would be forced to copy and move all elements down to make space first, which is much slower. However, it is difficult to handle random access in a linked list; you will generally have to start at the head and traverse the list n times in order to get to the index you want, whereas arrays can perform some very quick math and go directly there; random access of a linked list is thusly O(n), and of an array is O(1). Another con that a linked list has is that it takes up more space per element in the list. Because a node needs to hold a pointer or reference to another node to preserve the list structure, the size of the list is inflated by sizeof(reference)*num_elements. For trivial types in C/C++, this can come out to double or triple the size of the array. This relative cost diminishes as the size of the data object increases. Sometimes you have some information about a quality of some data, but no idea where it's at in a list -- so you can't do random access. A map attempts to solve this by indexing elements based on some quality. For example, say you had a map of state capitols. You want to know that capitol of Oregon, but you have no idea where that's at in the list, or the answer, so you can't brute force a simple list of capitol names to find it. One solution is to have two lists, where the list of states, state_list, corresponds exactly to the list of capitols, capitol_list (i.e. the state at index 7's capitol would be stored at index 7 in capitol_list). Given a state, you could iterate through state_list until you find that state, then grab the corresponding index in the capitol_list. However, what if Oregon's capitol wasn't stored at capitol_list[n], but was instead stored at capitol_list[\"Oregon\"]? This is called a Key Value pair (KV pair), where you link an element logically to some key (data to some quality of the data). Now in order to find the capitol of some state, you only need to know what state you want the capitol of, and the map will deal with finding it. The map does this by using a hashing function on the key to determine what spot in an internal list it goes in. The map now does a calculation based on the key entered and returns the value stored at that place in the list. Trees in general are pretty fun. Using trees you can make many problems very quick to solve by utilizing the properties of a tree (for example, your biggest element might always be your rightmost element, your smallest element your leftmost element, etc...). A (balanced) binary search tree can allow you to find a value in a tree in O(log n) time because each level of depth of the tree cuts the potential search space in half until there is only 1 element, the one you are searching for. More advanced tree structures can balance themselves to maximize search efficiency by ensuring the best structure to optimize a search. Because of the structure of a tree, it also lends itself to ordered traversals by visiting each node before, after, or in-between visiting it's children (preorder, postorder, inorder respectively). TL;DR: use an array if you want random access or know how many elements you need. Use a linked list if you will resize often or cannot guarantee a big enough contiguous block of memory. Use a map when you want to find data in a list just by knowing a specific quality of that data. Use a tree when you need to search for data often, or traverse your data in an ordered fashion."
],
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[
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[
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g4a681
|
Why are videogame maps located in a void?
|
I have been working on an essay about the Zetterstrand paintings and wanted to explain the void outside of a Counter Strike map, but I just don't understand why there is a void. The Programmers wil probably hate me for this, but can't you just make a 3d structure for a map in a box and then that is all there is? Or is there still a void outside if I were to ghost mode through?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnw6tip",
"fnw9awh",
"fnwf2xc"
],
"text": [
"If you don’t put anything there then you won’t see anything there. The void is the absence of any object the engine is meant to render. Sometimes this leads to trails of images because it just shows the last thing it rendered. Most engines now default to black if it can’t see anything. Most maps do have that sky box you mentioned but only in places you will see.",
"This touches on the general idea of how 3D graphics are rendered. To try and simplify as best I can, at each pixel the game asks \"what objects would be visible at this pixel\", finds the one closest to the viewer, and then displays that object at that pixel. But one possible option is if no objects would be visible (i.e. the player is starting at literally nothing). What colour should the pixel be then? This is essentially the \"default\" image, and there are several ways to determine this. The easiest is just a black void; that is, any pixel that has nothing to see is just black. Its easy, its simple, but it can look weird sometimes. Plus, a lot of times its nice to have a sky, but if you make the \"default\" a blank void then the sky would have to be a box floating in midair above the player, but that itself can look weird as the player moves around. Another option is what's called a \"skybox\". Instead of making every pixel default to black, you can make every pixel default to some texture (often a sky texture, hence \"sky\"box) based on the direction the player is looking. This gets a nice sky that looks right, but often the texture \"below the horizon\" is never seen because a player can never see through the ground, so even there the texture is just black because it doesn't need to be anything else.",
"> \"but can't you just make a 3d structure for a map in a box and then that is all there is\" This is exactly what CSGO maps are. a map inside a box, with a \"skybox\" (literally a box to place the sky textures and maybe some terrain models scaled down) hidden somewhere outside the map, and in the case of the Source Engine, is scaled up when viewed from inside the map. On Garry's mod if maps have a separate skybox you can place models inside it, and then if you go back to the main play area you'll see the model you placed as a giant 16x scaled up version. Other games may just have the skybox as part of the playzone box, instead of the smaller skybox method Valve used. Usually you'll find there is the game boundary (in CSGO that'll be buildings & closed gates on the outer edge you cant go past), which is a smaller box inside the larger skybox (the textures showing an appropriate background, such as an illusion of a larger cityscape) which once passed through places you outside the map bounds. From there it depends on how the engine handles things. There is a void because there is nothing there, so the game renders nothing. the Ghost command is likely just a different name for noclip to make it sound less developery and more fun. When you activate noclip you disable your character's ability to be obstructed by other objects (aka, no more clipping). This is not a restricted command, so it works on everything including the game boundaries. Once you're outside the map its less about the developers building \"nothing\" and more that literally nothing exists there so there is no thing to render. In some of Valve's Source games you might go through a white field before going into a blackness. That is likely just due to how light sources were placed on certain maps. Ultimately it's more that the void is an unintended effect of you leaving the play zone. Making games is all about taking shortcuts where you can. A lot of building models will turn invisible if you look at them from the bottom because \"the player will never see this part anyway, so lets save a couple rendered polygons\" (poly count adds up when you have a lot of objects). A lot of terrain items will clip through the ground, so they appear to be seamlessly in the ground. As far as CSGO goes, what you see as a player is different to what other players see you as. To others, you're a full body model, but to yourself you are actually a disembodied pair of arms with a gun. The arms just stick out from below the camera. A lot of these tricks you'll actually discover if you goof around in Garry's Mod since it's a free sandbox where you can access all the assets of the various source games you own. **Please enjoy your existential crisis as you contemplate whether or not our universe might act in a similar fashion.** TL;DR for 5's - you left the toybox and discovered that your entire universe is actually what's inside that toybox, with nothing created outside. Game makers didn't make the nothing outside the box, instead they didn't build anything outside the box."
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11,
7,
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[
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g4bnaa
|
Why do older games like to crash or have problems on newer computer?
|
My buddy has a pretty decent pc he can run Doom Eternal at a smooth 60, but when he tried to run Unreal Tournament 2004 it was pretty much unplayable and I was curious as to why.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnwqfcp",
"fnwh028",
"fnwgr2l",
"fnwg6c9",
"fnww14p"
],
"text": [
"Think of it as a language. If you'd jump back in time to a year around 1500 a.d. and try to talk to a person speaking the English language, you'd likely have quite some problems because the language changed a lot since then. Ways computers do stuff evolves too, and UT2004 simply doesn't know the latest vocabulary.",
"The most likely reason is software incompatibilities. Even if your hardware can easily handle the program, troubles arise if the game can't \"talk\" to your computer. You see, as computers get better, their software changes. However, when a program is produced, it is made to interact with the software of the day. Sometimes there comes a point where the newer software is using language the older game can't decipher properly, or the game language that is too old for the computer. Often this makes older games unstable, and - after a certain point - unusable.",
"Older games were written to be supported by older technologies. As a newer technology becomes more affordable and therefore more popular and more common across the board, the older technology stops getting as much attention and eventually stops receiving as much support. As a really basic example, old software used to ship on 3.5\" floppy discs. As discs became more popular, computer manufacturers stopped including 3.5\" floppy disc readers on their computers and included CD and then DVD readers/writers. And now that streaming media has become as popular as it is, and you can buy movies and games and music online without ever touching any physical media, they've stopped including even these CD / DVD readers on many of their products. That's not to say that CD's and DVD's don't exist, or that 3.5\" floppy discs don't exist. But if you want to use them, you have to go out of your way to find the solution to get your computer to read them (ie., buying a reader). Software is kind of similar in this case. In order to help keep program sizes smaller and keep programs running efficiently, and to avoid the potential for accumulating bugs and glitches, developers over time start trimming out the older stuff that isn't used as much. Or, maybe they develop something completely new and don't see a need to include native support for the older stuff to begin with because there's very, very little market for it since everyone's already moved on. In the case of computer games, 99.9% of the time there is a way to make it work, it just takes looking around online for the solution. There's actually a website, the PC Gaming Wiki, that seeks to document known glitches and their fixes with all computer games, so that there's always a way to get them to run. And the storefront GOG tries to implement as many patches as they can to make sure whatever older game they're selling works \"out of the box\" on your modern computer.",
"Older games are not optimised for newer operating systems. Basically you gave to trick a PC into running them for one reason or another. This can work for a great deal of time but sometimes you will simply encounter something that the game wants that is no longer used. Like a certain driver for playing videos.",
"The other answers in this thread are probably a bit more ELI5, but older PC games were generally made for computers with a certain speed and technology in mind. The first dual-core processor was only JUST released in July of 2004, so Unreal Tournament back then almost certainly wasn't designed to run on multi-core processors, and there is also the likelihood that there are certain kinds of bugs, many of which are what's called race conditions where threads of computation become \"stuck\" because they are each waiting for some condition to change in the other, that happens because the hardware we use now is so much faster than the hardware it was originally developed and tested on. A lot of games even older than that would get around some of these problems by syncing game play with the speed of the processor, so these games would basically become unplayable after a few years because they're just too fast."
],
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[
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g4c1hs
|
What is the reason that companies skip the number 9?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnwixp6"
],
"text": [
"Apple skipped the iPhone 9 because the iPhone X came out the year of the iPhone’s 10th anniversary. I don’t know about Windows though."
],
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3
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[
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|
g4cnai
|
I keep seeing posts, “I pointed my telescope here for 20 hours to give you this image.” Why does it have to be 20 hours of pointing? What’s happening exactly?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnwpwtq",
"fnxcv9p"
],
"text": [
"Simple version, there are 2 kinds of light a telescope camera gets: signal, and noise. Signal is what you want; it is light that came from the object itself. Noise is what you don't want; light from the atmosphere, from interstellar dust, cosmic rays hitting the detector, etc. What you can see in a picture depends on how these two things compare: this is usually called the \"signal-to-noise ratio\", or SNR. A high SNR means that you can see a lot of detail, while a low SNR may even mean that you can't see the thing at all. A high SNR is like listening to a flute play in a silent concert hall. A low SNR is like listening to a flute play on the side of a busy highway. When a chunk of light hits the detector, it doesn't know which it is, which means that it can't really figure out which is which. There is, however, one difference between the two that we can use: Signal increases with time, noise increases as the square root of time. For example: imagine you have two identical telescopes pointed at the same object. Telescope A spends 1 minute pointed at that object, telescope B spends 4 minutes pointed at that object. Telescope B will have four times as much signal, but only twice as much noise. This means that as you spend more time pointing at a single target, the SNR increases, which lets you see more and better detail.",
"Ok, I haven't heard the explanation of how do they do 20 hours? Is it 4 hours 1 night and 4 hours the next night and on?"
],
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5
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|
[
"url"
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[
"url"
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|
g4e1dr
|
Why does turning any device on and off often work in order to fix the issue?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnwvdtw",
"fnwvilu",
"fnwvoea"
],
"text": [
"When a device is running, it makes lots of notes to itself and reads those notes to work out what to do. Sometimes, usually when the device is being pressured to do more, it might make a badly written note that it has trouble reading later. Turning the device off and on again let's it get a new notebook to try again.",
"Many devices use software if some kind or another. If there is a computer chip somewhere in the devices circuitry, chances are that the device uses software one way or another. If the device uses software, then a good number of the problems will be software problems. Poorly written software doesn't know how to deal with every possible circumstance it might encounter, and it can tie itself in knots. Power cycling the device resets the software to a known good starting point, allowing it to function correctly once again. Often times, the unusual circumstances that caused the software to get confused have changed by the time you restart, so a restart fixes the problem.",
"When applied to electronics and computers, turning it off gives it time to get rid of all the extra charge in its components. In computers, the RAM card is the memory that allows you to do more things at any given time. Larger the RAM memory, the more multitasking you can do. Sometimes a program is badly mad that it leaves part of it still in the memory, even though the program has ended. It is kinda like picking up chocolate and having residue stuff on your hand after you finish it. While your hand is empty, the residue stuff makes doing other things with your hand a bit tougher. Turning it off and turning it back on is akin to washing your hand and cleaning it"
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23,
4,
3
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|
[
"url"
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[
"url"
] |
|
g4g79y
|
How does my ISP connect me to the internet?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnx8d90",
"fnxh5x5"
],
"text": [
"The ISP is the internet. The internet is essentially a massive collection of cables that cross countries and continents to connect the world's computers together. ISPs own the cables, from the cables that go to your house to the undersea cables that cross oceans. They make deals with other ISPs to connect their cable networks together to make a better connection.",
"If you were interested in a slightly more in depth answer. While ISPs do own most of the physical cabling, ISPs also connect to each other. They create what are called peering agreements which are business contracts and whatnot that dictate who does what. As for how your ISP knows where to send an individual packet, and it is done with the assistance of a routing protocol. Your ISP knows what IPs it owns and tells each of the other ISPs it peers with that it does own those IPs. Every ISP does this. Therefore it is possible to just hand an ISP a packet and it will route the packet where it thinks it is suppose to go."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g4hisy
|
How did humans 'survive' the annoyance of bugs in the wilderness before modern day conveniences?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnxjrjk"
],
"text": [
"It’s another element. You avoid them like rain or muscle through it if it’s necessary. Living in the wilderness is just different- you avoid threats and seek resources, and that’s really the closest thing to a schedule that you have- daylight to determine working hours and whatever your body needs to be comfortable, whether it’s getting out of the current situation, satisfying a curiosity, having a snack, preparing storage containers like baskets, whatever. With bugs, first, after a while of adjusting your diet to the local flora and fauna, your body’s chemistry and scent start to balance out with the environment and your presence isn’t as much of a shocking attention grabber- no major deposits of sodium in your sweat, no Cheetos in your stool or yellow lake 5 in your urine, etc. this starts to help. Then, like everything else around you, you start to notice their patterns, consciously documenting them or not, and adjust naturally to them. You start removing your shirt on hot days only when there’s also a breeze to keep insects off, whether you realize it or not. You cook and eat away from where you sleep, to avoid attracting wildlife to you at your most vulnerable. You learn that you need airflow under your rain shelters or all the flying insects flock under there during rain. It doesn’t take a genius, we all have the instincts. Then, of course, while hunting or tracking a threat and you can’t let bugs, scratches, etc. deter you, solutions include caking exposed skin with dried mud for camouflage and protection from the elements while laying still (bugs, sun, thorns). The wilderness is full of so many things- you can stand in one place and see thousands of problems all around you, while another stands in the same place and sees thousands of solutions all around them. It changes the way you see and interact with the world and yourself. I can use bug activity and presence to determine the condition or disturbance of a place in the wilderness. All those ants? Are they relocating the colony? Follow the line back, is that a footprint that smashed the mound? Like how when you sit in the woods birds will eventually become comfortable and occupy the trees around you again. You can tell the direction of any large animal or human approaching if you hear the birds silence and move away from a certain direction- somethings coming from there. Bugs are just something you learn to coexist with as part of the organism that is the world."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g4ina8
|
How the film's millimeter(mm), affect in a photo or recording?
|
Did the film's millimeter affect the resolution, colors and size of image?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnxqwj9"
],
"text": [
"In a broad sense it affects resolution. Film is basically clear plastic covered with very tiny crystals. You can think of these crystals like the pixels (or rather sub-pixels) on a monitor, the only difference is they aren't arranged in a nice neat grid but rather just a big jumbled mess like someone dropped them. Using different chemical processes you can make the crystals sensitive to different types of light, so you have red, green and blue sensitive crystals glued to the film. Once they are exposed to light another chemical process is used to lock in the colors. The larger a film negative you use (like 8mm, 16mm, 35mm or 70mm) the more crystals will fit onto the frame and as a result there will be more 'resolution'. The size of the image is determined by how far away the projector is from the screen and how the focusing element is shaped. In theory you can project an 8mm film onto a huge IMAX screen, it will simply look really bad because you'll be able to see the film grain very clearly. As I said the crystals are not distributed in a nice even way, it's more like painted sand which you can see when viewed very close. Color and grain size can also differ depending on the actual chemical technology used - older film used more primitive chemicals/procedures and so grain might be bigger and the color might not be as accurate."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g4kl7w
|
Google Domains
|
I know how DNS works, but why is Google able to sell a domain for $12/year? If they’re selling me the domain “helloworld” does that mean someone like name cheap doesn’t own it and can’t sell it to me? Or does it just mean that I claim helloworld and then google manages the service that redirects this domain search to my IP address?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fny12rn"
],
"text": [
"So what actually happens is there is a single central database for each of the different extensions (.com, .net etc), and each of these databases, called a registry, is run by a single company (so for example, a company called Verisign runs the .com registry) For you to add your own domain name into this central registry, you have to go through a 3rd party accredited registrar, like Google Domains/Namecheap/etc. You pay Google Domains $12 to register [ URL_1 ]( URL_0 ), then Google Domains will go to Verisign and if that domain doesn't already exist, add it into the Verisign .com registry for you. Then whenever you want to update or renew the name, Google Domains will go and update that entry on the .com registry for you."
],
"score": [
9
],
"text_urls": [
[
"https://helloworld.com",
"helloworld.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
g4rpls
|
How is Google able to create Google Earth street view?
|
This absolutely blew my mind. I decided to see where Liam Lynch (the republican) was born and wiki told me it was in anglesborough. I found it hard to found any pictures of it online. However, I found it on Google Earth. A tiny, remote village of > 100 people, yet Google not only knew about it but drove a car through it. Was this a process done solely by Google? Are new areas of the world still being captured even today? How long does this process take?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnz5l1c",
"fnz5u0q"
],
"text": [
"The map data is freely available from the government. What Google is doing is to package it up nicely and putting ads on it. The satellite photos and arial photos are taken by third party companies that specialize in this and is then selling the data to Google and others who wants to buy it. But the Street View is made by Google on their own. They have built a number of cars with a bunch of survailance systems on it and hire drivers to drive it through every street on the map. They even have more mobile versions that can be used while on foot for more difficult to access paths and trails.",
"The car (shown here URL_2 ) has lot of wide angle cameras which allow the software to \"merge\" them into a sphere view. Precise GPS tracking then allows to pinpoint each \"sphere image\" to a location. Indeed if you notice you move from setpoint to setpoint in Street view, sometimes the jumps are tiny, other times the jumps are further in distance. They also have a backpack version (shown here URL_0 ) which is used to map parks, rural areas and trekking paths. Regarding the update, on the corner of the street view windows you can see when the shot was taken, places with an higher \"interest value\" are re-mapped more often. Here ( URL_1 ) you can find where they have been, where they are headed and roughly mid page there is a slideshow showing the process of building and merging the images. Furthermore you can show that many areas haven't been mapped yet, fun thing is, you can apply to map an area if you can prove the experience and expertise for it, like trekking in the mountains have been done by professional \"Guide Alpine\" here in Italy. They also have a trolley version to map museums or internal places. Generally speaking the technology is always the same, just mounted in different vehicles (car, human, trolley, etc)."
],
"score": [
5,
5
],
"text_urls": [
[],
[
"https://duckduckgo.com/?q=google+Street+view+backpack&t=fpas&iar=images&iax=images&ia=images",
"https://www.google.com/streetview/explore/",
"https://duckduckgo.com/?q=google+Street+view+car&t=fpas&ia=images&iax=images"
]
]
}
|
[
"url"
] |
[
"url"
] |
g4s31z
|
Why is there a difference between when a screen is off and when it's showing a completely black screen? Logically you'd think they'd be the same, but obviously a black screen with the monitor on is slightly brighter.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fnz5pvn",
"fo1dwv3"
],
"text": [
"A typical LCD screen has a backlight. This is why the screen seems slighly illuminated, even though the actual pixels are black. Pixels just define the color and the backlight makes them visible. If your backlight was broken, you could hardly see anything on the screen. The great difference comes with LED screen. In LED screens each pixel is an individual LED - a small lamp - which defines the color, but also the brightness and there is no separate backlight. This makes black appear much darker.",
"Trying to go really ELI5 Nowadays there are 2 kinds of screens: 1. An array of many lights which turn on and off, creating the image. 2. An array of shutters that stops or allows pasing light coming from a backlight. The first one is called OLED, is newer and will give you true black (screen black = zero light) The second one is how liquid crystal displays work. They use liquid crystals to block or allow light to pass by applying an electric field. Liquid crystals and polarizers (parts used to shutter the light) will NEVER block all the light, hence you sill always see a dark image, but it will still allow to pass light. There are many more screens types, like old CRT, there are screens with ferroelectric liquid crystals, LED matrix like giant screen etc, but on phones and cellphones, they are all either LCD or OLED."
],
"score": [
14,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g4xlze
|
Why were people able to make alcoholic beverages for 1000's of years with no knowledge of bacteria or microorganisms? If you dont know you need to sterilize tools, why wouldnt you always get bad batches of product?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo032fr",
"fo04bhc"
],
"text": [
"Not knowing why you must do something does not prevent a person from doing it. The same goes for metallurgy or farming or whatever. They didn't know about chemistry or partial pressures or whatever, but they still knew how to distill alcohol and carburize their iron.",
"Sterilization and knowledge of bacteria and microorganisms isn't necessary for making booze, it's needed for making a booze with a consistent flavor profile across different batches (and, at a very basic level, making relatively safe booze that won't kill you based on the microbes used to encourage fertilization.) Making alcohol isn't a complicated process; if you put some sugar/water mixture in a cool dark environment with some yeast or bacteria and let it sit for a few months, you're going to end up with some form of alcohol. Controlling the exact ABV of the final product, the flavor profile, and all those other things that brewers are after: that's where sterilization comes in handy. Making sure that there's no old product still in there, possibly still fermenting or adding to the flavor profile, basically starting from a known baseline every time, is the advantage there; if you're making high-enough-proof alcohol it will sterilize things all on its own."
],
"score": [
8,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g53lf1
|
How do TV ratings work now that everything is streaming?
|
How do TV ratings work now that everything is streaming? How do networks know what shows are hits? How is it all compiled and analyzed? Did that woman who watched the Bee Movie 400 days in a row skew the data?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo1eyv4"
],
"text": [
"The data is much more accurate now with streaming services. They know every show being watched at all times and how many households are watching it. Absolutely every piece of data about your viewing habits is tracked and sold back to the production companies. The woman who watched Bee Movie 400 times doesn't matter because it's easy to tell that it is the same person, so it still only counts as 1 unique household. With network television and the old Nielsen rating system, the data isn't as perfect and its just a statistical approximation, because they aren't tracking everyone. If one household with a 25-35 year-old person is watching, they simply guess that means some thousands of people of that same age group are also watching."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
g549gw
|
How can a song in someone’s video on YouTube get them in trouble, but “lyric” videos can play that same entire song?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo1cl64",
"fo389h3"
],
"text": [
"Depends on what you mean by \"trouble.\" In most cases, trouble means demonitization, the person uploading the video no longer receives money from YouTube for the video, the money goes to whoever makes the copyright claim. If you are a creator that is actually trying to make money off of YouTube video content this is a problem. But if you're just a fan, don't care about making money (and possibly never even monitized the channel to begin with), it doesn't matter.",
"Lyric vids quite often end up having the entire audio track removed by YouTube. So they're not immune, they're just usually small fish compared to the vids you're talking about in terms of views."
],
"score": [
134,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g54uh9
|
how do laser pointed thermometer guns find a reading of the temperature?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo1aqzf",
"fo1azbn",
"fo1bsla",
"fo20d76",
"fo297he",
"fo1u7ic",
"fo2e15g"
],
"text": [
"The laser is just there so you know where the reading is being taken from. Everything emits infrared radiation as long as it's above absolute zero and if it gets hot enough it starts emitting visible light. The radiation things normally emit based on their temperature is a form of light below what the human eye can see unless it gets intensely hot. The laser thermometer is able to sense this radiation and determine temperature based on how strong and what \"color\" the light is.",
"The temperature of an object is related to the infrared radiation it radiates away. They are just IR-cameras with a chip that can calculate the temperature based on the distribution of IR wavelengths",
"Atoms jiggle around because of temperature. This jiggling jiggles the electrons too. When electrons move back and forth, they create light. In fact thats basically what light is, a history of the motion of an electron, propogating outward at the speed of light. We can relate the frequency/color of light to the temperature associated with the amount of jiggling in the atoms, which is what we call temperature",
"All heated bodies emit light out of it, and so does our body. Except, this light is not visible to human eyes. The laser pointer thermometers are like special eyes which can see this kind of light. Depending on the wavelength of this light, the thermometer can determine what is the temperature of the body.",
"Others did a fine job giving the explanation. The rabbit hole you're seeking is the search term 'black body radiation.' Very key and important problem to solve in the late 1800s for process control in making steel. The solution was literally a quantum leap.",
"1.Heated objects \"glow\" infrared light. We cannot see it, but we can feel it. 2.Thermometers can actually see that light and it's intensity. 3.One of the mechanisms for seeing is filtering - there is a photon detector (simple camera) behind a special filter that lets only infrared light go through it.",
"Depends on the gun. The ones you're asking about work as others have described. There is a type that uses the laser itself, and it is pretty accurate, but it's considerably more expensive, and not as easy to use. Laser light is extremely homogenous. All of the light is one wavelength, with very little variation. When that light strikes a surface, the movement of atoms in the material due to temperature causes a doppler shift, and by comparing the laser light that was emitted to the light that returns, the computer can see how much the spectrum of the light has broadened, and infer the temperature."
],
"score": [
580,
56,
17,
10,
7,
7,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g57cay
|
Why can live events be done in ultra HD on television but when its streamed on the internet the quality is usually super low?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo1pc48"
],
"text": [
"The streaming quality depends on your internet connection as well. Assuming it’s a good connection, (at least for YouTube, but I assume for other services) when a video is first uploaded, it uploads in standard definition to ensure that it at least exists. After time, assuming the user has the settings correct, it automatically re-uploads itself in HD. It could very well be that you are watching the recorded stream before it has had a chance to auto-upload in HD."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5bmh0
|
How does a new bank card know whether you have entered your pin once to then activate contactless payments? And how did all bank cards know when the contactless limit on card went up from £30 to £45 in the UK?
|
A customer asked me this at work and I didn't know the answer!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo2e0wu",
"fo2dy33",
"fo2hptu"
],
"text": [
"All these things are controlled, not by the card, but by the bank's computers. When you verify your new card with your pin, your pin, encrypted both by your card and by the terminal, is sent to the bank's computers for verification. So they know, and mark their record of the card as authorised to do contactless transactions. Contactless transactions, too, are sent to the bank for verification. Similarly, the contactless limit is also managed by the bank's computers. The terminal send the purchase request, with a signature produced by the card's chip, to the bank. The bank then sends back a reply that indicates whether the pin is required.",
"Your bank card holds very little information. It's the retailer terminal and the bank systems that know the limits and what has been activated etc after they identify the card.",
"Your bank card doesn't know much at all. I've never looked into this in depth, but in theory all it has to know is its number. Everything else is done between the card system and the bank. Say you tap your card at a store. Card: Hiii! I'm card number XXXXXXXXX! Card reader: *rings Visa* 'ey yo, I got this card here, number so-and-so. Is he legit? Also, he tapped. Visa: Yup, he's legit. Under the limit, too, so just tell him it's accepted and I'll note it down."
],
"score": [
8,
6,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
g5dp81
|
How do noise cancelling headphones work with the flick of a switch?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo2ocwx",
"fo2pit8",
"fo3iq2u",
"fo38xiz"
],
"text": [
"[Destructive Interference]( URL_1 ). Sound waves are pressure waves in a medium. As waves obey the [superposition principle]( URL_0 ) – that is, the amplitudes of waves add arithmetically – we can create a second wave with opposing amplitudes, thereby canceling out the original wave. Noise canceling headphones have microphones that measure incoming sound waves and create artificial sound waves canceling out the the incoming waves in the area around your ear.",
"Imagine a tug of war, with a long stick (instead of rope) with a ribbon tied in the center to see movement. Each side can push or pull. Lets say left side is pushing, right is also pushing, making the ribbon stand still. Same with pull, if other side is countering the same force, the ribbon in the center does not move. For an observer, ribbon stands still. So that ribbon barely moving is sound wave, by doing a counter wave(cancel wave), you stopped it.",
"There's a microphone on the outside that picks up noise. On the inside you have the speaker playing what you want to hear. When you turn it on, it also starts playing the opposite of the sounds that the microphone is picking up, thereby cancelling those sounds.",
"This is what i told my kids when they were five. There were a few digressions for some of the vocabulary like \"membrane\". I mentioned \"destructive interference\" to them, but only in passing. Sound is the action of waves of motion in the air or other things around you. When someone talks, their throat releases little puffs of air by turning airflow on and off really fast. Each little puff of air goes out their mouth. The air that is already there has to get out of the way. But then that air has to go somewhere, which makes some more air get out of the way ... all the way to your ear. The last bit of air pushes slightly against your eardrum and moves it a little. Pushing your eardrum back and forth makes you hear sound. The sound pushes on everything else too. If you cover your ears you can still hear sound. That's because sound waves from around you push on the outer layer of your hand, which pushes on the middle of your hand, which pushes on the part of your hand over your ear. So some of the sound gets through. Headphones work by pushing back and forth on the air right next to your ear, which shakes your eardrum without shaking the surrounding air very much (because they're so small). There's a little membrane (sort of the size and shape of your eardrum, actually) that gets shaken back and forth by the electronics in the headphone. Noise canceling headphones work by actively measuring how much sound is getting through -- in early ones, there's a little microphone on the inside that measures the sound right next to your ear canal. Newer noise canceling headphones use clever electronics to measure the sound using the same membrane that makes the headphones' sound. The headphones can push the membrane around really fast, so they push it in the opposite direction from whatever sound they detect in there. Some people like to say that causes \"destructive interference\", which is a pair of really big words you'll learn later. Other folks like to say that it makes the headphones act like a near-perfect strong wall that doesn't move when sound hits it (or even moves *against* the sound to make u for sound that leaks around the headphones). The reason you can't have noise canceling loudspeakers is that the noise canceling effect only works over a very small region. The region has to be small compared to the length of the sound waves. High pitched sound waves are about the size of a whistle, so you can't cancel sound easily in a space much bigger than that. Fortunately, the inside of your ear would totally fit inside a whistle -- so it's small enough for the noise canceling headphones to work. Noise canceling headphones play music into your ears a really interesting way. They're using something called \"feedback\" to measure how to push the membrane around. The headphone senses the pressure near your ear, and adjusts the membrane to keep it constant (blocking out sound). That is called \"feedback\" because the headphone *feeds* the measurement *back* into its membrane. To play music or something, you inject a fake signal into the feedback device, and the headphones compensate for it. As far as the headphone knows, it's keeping your ear as silent as possible. But you're messing with its senses, telling it there's \"anti-music\" coming in. It compensates by generating music to try and block the anti-music. Since the anti-music isn't real, you hear the music in your ear."
],
"score": [
27,
7,
6,
5
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Superposition_principle",
"https://en.wikipedia.org/wiki/Wave_interference"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5dtr9
|
What happens to the files on your computer when you "empty the recycle bin"?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo2p9xo",
"fo2p24k"
],
"text": [
"The computer keeps track of the location of every file. So it knows what areas of the hard disk are being used, and what is free to be used for new files. When you send something to the recycle bin, nothing changes on your hard disk, and the computer will still treat those areas of the hard disk as in use. This is what allows you to easily recover deleted files. When you empty the recycle bin, nothing happens to those files, not immediately anyway. However, the computer now treats the area of the hard disk where those files are as available for use. So over time, those areas will get overwritten by new stuff.",
"The file system not only keeps data, but also a record of how to find the data on disk. When you empty, you’re telling the computer to delete that record so it doesn’t know how to find the data anymore. The original data is still there, it’s just that the spaced it occupies is free to be written again."
],
"score": [
15,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5gqkg
|
Packets are sent in binary, but how does the CPU know what to convert the binary into? (eg. an image, text, etc)
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo36jca",
"fo3lapn"
],
"text": [
"The very first packet of a network transmission will have particular bit fields which further indicate what protocol the msg is using and how many packets in total make upon the msg. Each packet will also indicate stuff like \"this is packet 2 of 278\" \"I am x bytes long\" and \"here is some error correcting stuff so you know I got sent correctly\". Once all of the packets for a msg are received, a higher layer protocol and drivers will strip out all of the packet headers and reassemble the data within. In the case of sending an image, the newly reassembled image file will start with some special bits to indicate what type of image file it is (jpg, png, gif) and more information about how to display it.",
"Packets aren't sent in binary. You're thinking data is sent over a network cable like morse code, dots and dashes to represent zeros and ones. This was actually true in the 1940s, but transmission got more sophisticated than that shortly thereafter. Data transmission on a wire follows the same rules as data transmission over the air, you've got frequency, amplitude, and phase, and through a combination of modulating all of them, you get an extremely sophisticated signal structure that encodes multiple bits of data at a time. Believe me, this modulation stuff gets crazy. The limits of our ability to pack more data into a frequency comes down to accurate clocks. You need extremely precise clocks to be able to transmit or receive and decode the analog radio signals. All modern data buses, like USB or Ethernet, use differential signaling. You have two wires, and they are both sending the same signal but 180 degrees opposed - mirrored signals. The information is encoded in the difference between the two. This way, if electrical noise, which is now days ubiquitous, effects one signal wire, it's going to affect the other signal wire the same. The noise distorts both signals equally, but since the data is in the difference between the two, that part doesn't change. Your screen is nothing more than a glorified Excel spreadsheet. \"Pixel\" is a portmanteau of \"picture element\", and *typically* consists of 3 sub-elements, of red, green, and blue. Imagine an Excel spreadsheet where the columns repeat, red, green, blue, red, green, blue... Each sub-pixel can have a value of 0-255 (8 bits), where 0 is white and 255 so saturated with that color the sub-pixel is black. So picture data is just 0-255 color values for each sub-pixel, for every row, every column. The data is written to memory - called a video buffer, and that memory is shunted off, over the video card, over the cable, and to the video controller circuitry on the monitor itself that drives the display. There are programs out there that will convert any image into an Excel spreadsheet if you wanted to see, and then you just zoom out the spreadsheet or stand back from the monitor and see the colors blend and the picture appear like an illusion, because that's what video displays are."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5hs54
|
how does game streaming servers handle games and users at once compared to personal computers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo3m5wh",
"fo3dw3z"
],
"text": [
"Having been a production server engineer for almost 10 years, I can tell you it primarily comes down to CPU and network. These days servers are most commonly are equipped with \\~24-core Xeon processors, and while probably not faster than your own personal computer's CPU on any one job, it can do a lot more jobs at the same time. To put into perspective, on a single server with that processor you could deploy 24 dual-core virtual machines while retaining nearly full CPU performance in every VM, even if they were all to use 100% of their available CPU at the same time. As far as network goes, servers are commonly equipped with a network interface capable of at least 10-25 Gigabits of bandwidth, and they will have multiple network interfaces. The datacenter they reside in will be providing at least thousands of Gigabits of bandwidth. You on the other hand, probably have at most a single 1 Gigabit network card on your system, and your internet provider likely can just barely get you 1 Gigabit of bandwidth.",
"They are just really, **really,** # [fokkin huge]( URL_0 ) with a ludicrous amount of CPUs and GPUs connected that they can provision to users."
],
"score": [
7,
3
],
"text_urls": [
[],
[
"https://stadia.dev/static/images/about/about-data-center.jpg"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5hvc5
|
How are we still able to communicate with Voyager 1 and 2 so far away?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo3hnpi",
"fo43ain",
"fo3dj5a",
"fo3dvak"
],
"text": [
"> How do V 1-2 find the exact location to send the signal to in this vast universe? A dumb down explanation. Think of a flashlight and how it illuminates larger areas with distance. So further away you are, more area that light covers. At this point V 1 & 2 are so far out they don't need to know earth's exact location, they just need to find the sun and point at it. Should the earth be a little left, a little right, dead center or is the earth behind the sun is all either two need to know. And, like others have already said, you can orientate by looking at other stars (yes V1 & 2 have gyroscopes). Now the real question is just how bright is that flashlight and how good of an eye on earth does it take to see it because that flashlight now illuminates an area billions of square miles. > How is the signal not getting trashed by meteors etc? Distances. You don't rely on one person to receive that signal. You use many stations spread it out over the globe and in orbit if you can. Then hope and pray one of them can see it.",
"> How is the signal not getting trashed by meteors etc? Its hard to appreciate just how much space there is in Space. The odds of hitting anything while passing through the asteroid belt are so small *that NASA doesn't bother to calculate them for missions crossing through that region*. Every asteroid is at least tens of millions of miles away from its nearest neighbor. That's dozens of times the distance to the moon. If you were standing on one asteroid, you wouldn't be able to see any others. Space is *empty*.",
"> How do V 1-2 find the exact location to send the signal to in this vast universe? Math and sensors. Also, radio waves work kinda like flashlight beams with regards to expanding. If you're firing them off from millions of kilometers \"vaguely in that direction\" still hits the target. > How is the signal not getting trashed by meteors etc? Meteors are exceptionally rare. Also, radio waves go right through most of them.",
"The only force operating on the probes is gravity, so using a bit of math, they can know exactly where the probes are at any given time to point their transmitter and receiver at them. As for the signal, space is really, really empty. In spite of the distance, once outside Earth's atmosphere, there's unlikely to be anything between us and the probe. The signals are weak at such a long distance, but since we know where they are and what to look for, electronics can filter out background noise to discern the transmitted signal."
],
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|
[
"url"
] |
[
"url"
] |
|
g5n4z9
|
What do the numbers in anti-aliasing represent (e.g. MSAA 2x/4x/8x)?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo4dtal"
],
"text": [
"How often the filter is applied. So at x8 the filter is applied 8times and edges look very smooth but ur gpu may be on fire tho"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5nc9w
|
How do solid state drives (SSD) store and retrieve data?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo4mjg2",
"fo4qysy",
"fo4ybmq",
"fo4ua0w",
"fo50elk",
"fo4y2uq",
"fo4rwjo",
"fo58km8",
"fo5cq5l"
],
"text": [
"On a very basic level, an SSD is like a large plastic sheet covered with a grid of those bumps that you see on soda-cup lids. To write a file to the disk, you pop and unpop the bumps to represent the file in terms of 1s and 0s. To read from the disk, you run your finger across them and feel the pattern of popped and unpopped bumps. These bumps are called flash memory cells, and there can be billions or trillions of them packed in several tens of layers on a silicon chip. They consist of microscopic transistors and capacitors, and they're 'popped' and 'unpopped' by applying a positive or negative voltage across them, which either stores a tiny amount of electric charge or releases it. To check the state of one of these cells, you can measure the voltage across it to see whether there is charge stored in that cell. A controller chip on the SSD receives read and write commands from the host computer and applies the necessary voltages to the right rows and columns of cells to write and read blocks of several thousand cells, called 'pages'. The exact format of the data on the disk is entirely up to the controller and may not be consistent across different models of SSD's -- so long as the controller implements a common protocol (SATA or NVMe, for example), the computer doesn't care. These cells aren't perfect, and repeatedly writing and erasing a cell causes it to wear out and lose its ability to store charge. When this happens, the controller can no longer read from those cells, causing data loss. To combat flash memory wear, an SSD controller is smart enough to spread out the reads and writes across the many billions of cells at its disposal. This process is known as 'wear-leveling'. Even with this algorithm in action, a disk has a limited amount of read-write cycles before the probability of a data loss incident becomes more than negligible. This quantity is usually expressed in write cycles, where one write cycle consists of using every cell on the disk once. Because of this, larger-capacity SSD's take longer to fail on average.",
"There's one really fascinating thing that the other very good explanation didn't mention. If the data is stored as charge, why doesn't it just leak out as soon as there's no power to the computer to hold the charge in the cells (like what happens in RAM)? SSDs hold the charge in an impenetrable box from which there is no exit. But here's the rub--if the box is going to be impenetrable and require no power to hold it closed, then it cannot have a \"lid\" or \"door\" which could come open when the power is off. As a result, there is no entrance to the box either. The only way the charge can get into the box is to kind of \"teleport\" through the wall of the box using a process known as Quantum Tunneling. Although the box is impenetrable with no openings, the charge is able to pass through the solid barrier and suddenly find itself on the other side, trapped inside the box.",
"Can we get an ELI5 on the quantum tunneling that some of the comments and sub comments have mentioned?",
"The basic element inside a solid state storage device like an SSD is called a floating gate transistor. More on that in a moment. Each of these devices used to store a single yes or no called a bit: 1 or 0. Now each of these devices stores a few yes or nos. Typically 3: 000, 001, 010, 011, 100, 101, 110, or 111. This increase in questions that can be asked to a single device is why you can have really big SD cards and SSD drives. That and scaling. The size of one of these devices is on the order of 40 nm. Your hair is about 200 um or 200,000 nm across. How do these devices work? If you have ever rubbed your hair on a balloon and attracted your hair to it, you have seen something called static electricity. On that surface you have trapped some electrons. That is possible because the rubber is an insulator. On your hair of you have left the absence of electrons. This allows there to be a force between the absence and the extra electrons. It is this force that makes you hair stick up opposing gravity. The force is described by an electric field. Floating gates on transistors trap charge on them too just like the balloon, only it stays a lot longer because the layer of insulator the charge is trapped in is very isolated. This charge can attract mobile charges into a region of the transistor called the \"channel\". The channel is physically directly under the gate. Think of the charges as a liquid, say water. If the channel is full of water then it conducts, if it is empty of water is does not. It conducts better if there is more water. So depending on how much charge you store on the floating gate you will get more or less conduction. If we measure how well it conducts we can measure some levels and assign those levels values: 000, to 111. How do we get the charge on the floating gate? Do we have little hairs we rub on the gate? No. What we do is we use another gate. This one is attached to a chunk of metal which allows us to flood it with electrons. If we put enough electrons on it, it will create such a strong electric field to the channel that some of the very crowded metal will jump to the floating gate, this is called \"tunneling\" it is governed by a branch of physics called quantum mechanics. We make the other gate crowded by putting a high voltage on the metal gate. The reason flash memory or SSDs wear out is that sometimes the electrons jumping to the floating gate hit things instead of jumping between the atoms they smack into them and break chemical bonds. When they do this they change the properties of the insulator that lets the floating gate store charge for a long time so some of the electrons escape just like they normally do from the balloon into the air (due to humidity). This makes the floating gate transistor \"forget\" the information that was stored on it over time as the high level of 111 becomes 110 which is the wrong answer, not what you stored. If the memory is not reliable to remember then its bad/dead. Typical flash memory can only be written a few 1000 times now before it starts to forget too quickly because everything is so small and fragile.",
"Write: They inject electrical charges in the form of trapped electrons into \"cells\". Read: They check the voltage of said cells. Simplest form (SLC) would have the cell at 0v for a 0 and then a positive voltage for a 1.",
"A bit on an SSD is like a light switch. You can flip the switch to change the state of the light (Write) or just look at the light switch to know if the light is on. (Read)",
"Little teeny tiny gates that store a 0 or a 1 called NAND latches will store each individual bit. Now for reading and writing, each instruction comes in as a string of “coded” binary and it says “Hi! Here’s my start index, my length, and bit offset. Write me!” And the controller writes where it thinks is best through a series of checks.",
"Solid State Memory is just a bunch of batteries that are charged or not. Every battery is a one (charged) or a 0 (not charged). A computer stores data in these batteries by setting the charge or draining the charge in each battery. Later, it can measure the charge in each battery to see what is stored there.",
"A disk drive has billions of tinny reflective dots on the disk that can can be adjusted to either be reflective or not. A tiny camera sees reflective or not and allows your whole computer to run. An SSD works with something called a \"NAND\" gate. Long story short, it is a tiny group of atoms that will produce and electrical charge as long as one of the two inputs to the NAND (not and) are off. For reasons I won't get into, a NAND gate can be used to create all other logic gates. When we figured out how to make them the size of a few atoms, they became a viable way to store yes or no data bits."
],
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|
[
"url"
] |
[
"url"
] |
|
g5tok3
|
How does compression of files work on my computer?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo5ifpw",
"fo5poxx",
"fo5r91s"
],
"text": [
"Most compression algorithms work by removing repeated data Imagine a book for example. As your read through the book you discover that the most common word used is 'complex'. So replace that word with a placeholder like '%', and at the beginning you add an index that has the line '%' = 'complex' '%' takes up only a single character, while the word complex needs 7. So if the word is in the book 1000 times, you just saved 6000 characters without losing any information. Do this for a lot of words and you've saved a lot of space. Compression algorithms work in a similar way, but they look for repeating patterns in the binary data.",
"So a file has the following binary : 1010111100000111111010 The compression software will notice the repetitive bits and store them roughly like this: 10101^^^×4 0^^^×5 1^^^×6 010 This is just an easy representation but there are various techniques and methods by which data can be sorted and stored by compression systems.",
"Say you want to write a book on the politics of England. You find yourself having to write the word \"Antidisestablishmentarianism\" alot as you discuss the relevant time. Now writing \"Antidisestablishmentarianism\" a lot takes a long time, so rather than repeatedly writing \"Antidisestablishmentarianism\" You take another piece of paper and write down %1 = \"Antidisestablishmentarianism\" And everytime you want to write down \"Antidisestablishmentarianism\" , you write down %1. Let's see how the preceding text looks like if we did this: > Say you want to write a book on the politics of England. You find yourself having to write the word \"%1\" alot as you discuss the relevant time. Now writing \"%1\" a lot takes a long time, so rather than repeatedly writing \"%1\" You take another piece of paper and write down \\%1 = \"%1\" And everytime you want to write down \"%1\" , you write down \\\\%1. See how much shorter it is? Now if your history of England went on and you had to write \"haemophilia\" alot, you write down %2 = \"haemophilia\" and do the same and so on. So why not just do that for everything? Because eventually the table you're writing stuff down on gets bigger than the file you were copying. If you only use \"Floccinaucinihilipilification\" once in your book, you're just wasting time and space writing it down in that paper you made. Alot of algorithms are done to balance these factors."
],
"score": [
35,
5,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5vh5i
|
What do all those numbers and letters and such mean on pc parts?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo5uvp3"
],
"text": [
"Well first of all, every PC part has a different function and means different things. A four digit number for a CPU has nothing to do with a 4 digit number on a RAM. I'll try to give you as much info as I can. This is going to be a long post so bear with me. * **Motherboards** Motherboards are built upon 'chipsets' usually Intel or AMD. So when say you have a Gigabyte B360M Gaming HD motherboard, it means it is built upon an Intel 'B360' chipset. What does B360 means? [Find out here.]( URL_4 ) Also [AMD Chipsets here]( URL_4 ) . & #x200B; * **CPU** CPUs are mainly from Intel or AMD.Intel's main series is the 'i' series. i3, i5 and i7 have 3,5 and 7 as arbitrary numbers. They don't mean anything other than 7 > 5 > 3 so i7 > i5 > i3 (not always, but 90% of times) Say you have an 'i5-9400F' . You know what i5 means. The first number, 9 , means it belongs to the 9th generation of intel cpus. the next three digits denote its 'power'. so 9700 is powerful that 9400. Get it? F means that it does not have integrated graphics. So what do all these letters like K,U,H means? [Find out here.]( URL_2 ) It's similar with AMD Ryzen. Ryzen 3,5 and 7 is simply a nomenclature. Means nothing.Ryzen 5 3600X means that it's 3rd generation, powerful than any ryzen 5 having last 3 digits smaller that 600 and X means it's slightly better than the base version - 3600. & #x200B; & #x200B; * **GPU** Nvidia vs AMD here. eg. Nvidia 1080 Ti - it means it belongs to 10th generation. Last two digits are 80, so it's more powerful than 1030, 1050, 1060 and 1080. The Ti means it's a special version which is slightly more powerful than the base 1080. eg. AMD RX580 - 5th generation. Faster than 570, etc. & #x200B; * **RAM** [DDR means Double Data Rate.]( URL_3 ) the number next to DDR gives it's generation. DDR4 is the 4th and latest generation. The 4 digits after that denote the frequency. Therefore, DDR3 -1333 means 3rd generation DDR with 1333 MHz frequency. * **HDD or SSD (Storage)** They are either based on [SATA]( URL_1 ) or NVMe ([PCIe]( URL_0 )). Sata has 3 versions - 1.5 Gbps (obsolete) , 3Gbps (the one you mentioned) and 6Gbps (currently widely used. latest and fastest). It means the hard disk can transfer 3 Gigabits = 375 Mega Bytes per second. If you have any specific questions, PM me. I can't mention every single part in the world here. But I hope you got the gist. Also click on the relevant links I provided to get more info"
],
"score": [
19
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/PCI_Express",
"https://en.wikipedia.org/wiki/Serial_ATA",
"https://www.howtogeek.com/223020/what-are-the-meanings-of-intel-processor-suffixes/",
"https://en.wikipedia.org/wiki/Double_data_rate",
"https://en.wikipedia.org/wiki/List_of_Intel_chipsets"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5xiqk
|
How does YouTube not run out of space?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo63j7e"
],
"text": [
"Google keeps buying hard drives. And when older videos have few viewers it gets archived on tape and only the first few seconds is stored on hard drives. If you try to watch these videos there are tape robots fetching the tapes, unspooling them into tape readers and starts playing the video from tape before you are done watching the few seconds that is stored on hard drives. This system is in place because tape is much cheaper then hard drives. But Google still keeps buying more and more hard drives as the volume of videos uploaded is still increasing."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
g5ypu3
|
How does a virtual machine emulate a disk larger than the host machine?
|
For example, if I was to install Parallels on a Mac, install a MacOS Sierra virtual machine with 1TB hard disk, but the host machine only has 320GB. *(*In reality, the host machine would have something like 230-240GB out of 320GB used *)*. You can't physically have more space than available on the machine, so how does it emulate that? I understand the VM is a file, but is this a sort of emulation? I've seen similar questions on how a virtual machine works on ELI5, but this is about one aspect of it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo6c40u",
"fo6hand"
],
"text": [
"Virtual storage volumes are stored *sparsely* on real drives - only the parts of the virtual volume that have data written to them need to be remembered. Pretending you have 100MiB of no data and pretending you have 100 TiB of no data takes about the same amount of actual storage space. Allocating more resources to your VMs than your physical machine has is called overcommitment. In many cases, your VMs will have varying load levels and many of them will not be using all the resources they theoretically have available, so performance is fine. But if load goes up high enough on enough of them at the same time, it causes serious problems. For storage overcommitment, you're creating the possibility that the VM will try to save a file to its virtual drive which has plenty of space, and the virtualization tools will try to find space for it on the physical drive which has no space. The VM will then be unable to save the file, potentially leading to loss of data.",
"Well, the space you give a virtual machine isn’t it’s actual space, rather space it’s allowed to use. Thunk of it as a software limit to the size of the operating system being virtualized. It makes sense to do this, as you want to sandbox the environment in the case of virtual machines. This is good for testing old computer viruses for fun."
],
"score": [
13,
3
],
"text_urls": [
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
g5yrwq
|
Why do storage device such as HDDs, SSDs, USBs etc advertise that they are a certain storage but doesn't technically have that amount of storage?
|
I bought a 8tb hard drive but only has 7.27tb of usable space. If I do 8,000,000,000,000÷(1024×1024×1024) = 7.450tb. What happened?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo6aq6k",
"fo6d2vi",
"fo6ddhz",
"fo6b2ss",
"fo7b1vt",
"fo77l3k"
],
"text": [
"There are two ways to count the number of bytes in a hard drive. The SI system that is used everywhere else uses base 1000 for each increment. So 1KB is 1000 bytes, 1MB is 1000KB and 1GB is 1000GB. This is simple for us who count in base 10. However computers use base 2 to count. And due to technical reasons it is simpler to make some storage mediums an even number in base 2. So it became common to use a base of 1024 instead of 1000. It just happens that 1024 is an even number in base 2 and quite close to 1000 that the difference does not matter much in practice. So 1KiB is 1024 bytes. However the bigger the numbers the bigger the difference becomes. So 1TiB is about 1.1TB. Naturally hard drive manufacturers wants to use the bigger numbers when advertising the storage capacity. So they tend to use the SI unit. While computer systems does not care and tends to list the unit that is simplest for them. So an 8TB disk contains 8,000,000,000,000 bytes of storage space which is 7.27TiB. Notice the different units, the different notiations is also of newer age so it is not always used.",
"Your math is wrong. You divided by 1024^3 when you should have divided by 1024^4 because there are four \"levels\": kilo, mega, giga, tera. 8E12 / 1024^4 = 7.276",
"Computers internally work in binary, so various things naturally have limits that are round numbers in binary. Eg, if a CPU has 16 address lines that gives you 2^16 = 65536 possibilities to work with. Also it's easier to have all possibilities covered than to account for special cases, like \"This chip only has connections that allow for 65536 different memory addresses, but only 60000 bytes in it\". That's why RAM sizes are pretty much always some power of 2. The computer industry kind of redefined the metric prefixes like \"kilo\" and \"mega\" to the nearest power of two for the sake of convenience. Hard disks though work differently. There's no particular reason why any hard disk would have storage that neatly matches a power of 2. It might be easier to think of with magnetic tape: you can have a tape of any length you want. There's no reason why it has to be any particular length that makes for a round number in any way. You're usually limited by physical space, and so if in what space you have you can fit 187.65 meters, then that's what you get. These days we tend to get disk capacities in pretty round numbers, but before you'd get things like a 1.44 MB floppy, a 40MB disk, a 170MB disk, a 850MB disk, etc. So that's one part of it. For SSDs, you're back to binary round numbers, but with a catch: SSDs internally have more storage than they show to the host because they need additional space to manage themselves and for redundancy. So a disk that contains 512 MiB of flash (512 * 1024 * 1024) may well expose 500 000 000 bytes to the host, and keep the difference for its internal workings. And of course for marketing, bigger numbers are better, so HDD manufacturers insist on the original metric prefixes with the smaller values (1000 bytes) rather than the improvised definitions the industry came up with (1024)",
"Hard drives are advertised in base 10, base 10 is easier for humans. In base 10, for advertising 1GB,=1000 MB. In base 2, which your computer uses, it's actually 1024 MB, which causes advertised capacity to be less than actual.",
"None of these responses actually address the question. The OP clearly understands the difference between TiB and TB. The discrepancy he/she is seeing is due to an arithmetic error. 8 trillion bytes = 7450 GiB = 7.27 TiB. The OP did not divide by 1024 the right number of times.",
"There's an additional fun factor at work here, and it stretches back to the early days of computing. It used to be that the companies that made the physical disks (in those days, drums, or tape drives) where not even remotely the same company that made the computer and the operating system. The \"disk\" engineers would calculate how many bits of data would fit onto the physical device. When doing so, they don't take into account any of the requirements for an actual computer, or actual file system. Their calculations will be higher than the computer maker's calculations. For example, a computer maker might buy a memory \"drum\" with 40 different tracks. When the time comes to actually use it, they realize that they need to know exactly how far the drum has spun around (they need to know where to start reading). So the computer maker decides to use an entire track of the drum as an index: it's got a special pattern that the computer can detect in order to tell where each track starts. From the drum maker POV, the drum has 40 tracks. From the end-users POV, there are only 39 usable tracks. In the same way, floppy disks have a \"raw\" capacity; it then gets formatted by writing a special pattern to the entire floppy disk. When the disk is read, the computer can tell when it's reading the special pattern and when it's reading real data. The old CP/M OS was famous for this; each computer maker (and there were dozens or hundred of them) would each have their own special way to format a floppy to the point that floppies from one system would be unusable on another. AFAICT, it totally sucked. There's a great analogy to this, BTW, with dial-up modems. A byte is normally 8 bits, but to a communications engineer, it's 8 bits, plus a start and 1.5 stop bits. (yes, 1.5, because they can do that. It's all about the timing). So why does this persist? Because the disk makers don't know how you'll use the disk, even though a reasonable person would guess that it's going to be used in a Windows computer. But even there, there are different ways to format a disk, so the disk makers don't \"know\". Lastly, it persists because there are multiple disk makers, and each one has an incentive to use the old system because it results in a bigger but still technically correct number. If I was president (or Elizabeth Warren and in charge of a consumer org), I'd fix it. It's dumb and inefficient, and my industry should be neither of those things. TL/DR: history, and a blizzard of technical reasons beyond just binary versus decimal."
],
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|
[
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[
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g62evs
|
Why can the task manager stop lagging programs but we can't ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo6ysch"
],
"text": [
"Because the Task Manager is very, very rude. When you click on the \"Quit\" button in an application, you are asking it nicely to clean up after itself and shut down. The application might say no - for example, it might say \"you haven't saved your file yet; do you want to do that before I quit? You might lose your data.\" But when you click on \"End Process\" in the Task Manager, you're not taking \"no\" for an answer. The application will quit, now. No cleaning house. No friendly messages. And if the application can't quit, the Task Manager will force it to quit. The Unix console equivalent makes this a little clearer. The command is \"kill\". You can kill nicely (\"kill -s quit application\") or you can kill with extreme prejudice (\"kill -9 application\"), but you're still killing it."
],
"score": [
19
],
"text_urls": [
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]
}
|
[
"url"
] |
[
"url"
] |
|
g62oz5
|
Why is computer audio so "hard"?
|
I've been messing with PCs since the early 1980s, so I'm asking this question froma place of someone who configured token ring networks and hardware dip switches to make cards work. Forever, installing/configuring **sound** on computers has seemed far more complex, kludgy, non-intuitive than nearly any other function; moreso than video, moreso than networking , moreso than other peripherals. The driver downloads are (now) enormous, and even Win10 which has done a pretty decent job of simplifying most things STILL has the most infuriating quirks buried within layers of layers of control systems - my new gaming laptop for instance has Realtek sitting atop the standard Win10 sound control systems (which themselves sit atop older, to me clearer, property controls and popups) and STILL there are controls and settings that are only accessible through certain settings and not others. I'm not here to harsh on Win10 precisely, my question is more general for hardware engineers and anyone that knows: why is audio control on PCs so Byzantine, and doesn't seem to be getting better? Thanks!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fo72tks",
"fo7i7z1"
],
"text": [
"Windows has a kludgy audio implementation out of the box. Once you look into the world of ASIO and have hardware and software that have been developed well (aka pricey) audio on windows is amazing. That being said...on the Mac side, many pieces of hardware just work by plugging them in, no special downloads needed.",
"The real core of this, I think, comes back to two things: backwards compatibility and the complexity of sound vs the simplicity of digital formats, and I think that second one deserves to be dug into first. Making sound come out of a speaker using an analog electrical signal is an easy enough task, to the point that microphones and speakers have been around almost as long as we've had electricity as a utility. Since electromagnetic current can be modeled as a wave, and sound is just pressure waves hitting our ear drums, it's pretty easy, relatively speaking, to take the properties of an EM current's wave and turn them into pressure waves using magnets and large speaker membranes; it's simple enough that I made a speaker out of a magnet, some wire, a paper cup, a headphone adapter, and scotch tape as a project in HS physics, and it worked well enough to blast The Offspring over the dull din of chatting students in my physics class one day. Digital signals, as you know, are all 1's and 0's, and as you also likely know, those 1's and 0's represent an on or off state of a certain current. Since this is all that a computer modeled on binary arithmetic can natively produce, we need to make an interface that can take some sort of 1 and 0 signal and turn it into an output current that has wildly varying amplitudes and frequencies. I don't personally know exactly what hardware wizardry goes on in a sound interface, but at a high level what a sound interface has to do is either take in an analog signal and convert that to a sequence of 1's and 0's, or take a sequence of 1's and 0's and convert that to an analog signal, and to do that across the range of human hearing for pitch and volume (or frequency and amplitude respectively), at a rough guess they have to design a way to make a binary-speaking chip send out signals of certain magnitudes (likely by taking exact bit values and adding them up to certain net current levels) and make them vibrate at a certain frequency (I have to assume that this is done by modulating on/off somehow, my knowledge breaks down a bit here unfortunately) and then change that immediately when called for. And all that is just to get a stable sine wave, which is the physics 101 version of how we model sound; any organically-generated sound is going to be a complex waveform that varies slightly in pitch, volume, and other characteristics based on any of a thousand different things. Just for instance, your voice is a combination of your vocal cords vibrating at a certain frequency, air coming through your sinus cavity, the shape of your mouth altering the form of the waves, the placement of your tongue and whether it is blocking airflow (or causing percussive waves through \"clicking\" or striking parts of your mouth with rapid movements), the echoes and under/overtones that result from your environment; and if your voice is singing something while a piano or guitar or other instrument plays, an audio mixer has to take in both of those signals and produce a single waveform signal that represents both of those played simultaneously. All of this, to get it right in a digital format, ends up taking a pretty big amount of processing power to deal with, particularly when it comes to input (though output has been more streamlined), and because sound is something people wanted even in the early days of computing, rudimentary systems of dealing with sound got developed before we had the systems to deal with more complex waveforms, and since people didn't wait until we had realistic 3d graphics to make games, they made do with the audio hardware of the time to make sounds happen with their games. And all this ends up leading to: backwards compatibility. At its heart, Windows 10 still has some bits of MS-DOS in its core programming, to the point that to this day you can't name a file or folder con or nul or any of the filenames that were reserved for the makeshift ways that DOS used the same file read/write syntax to control external devices like printers, because if they changed that, it might break some legacy system that some company, potentially an important-to-the-world-functioning company, still has to use because it relies on a piece of hardware or software from a company that went out of business 20 years ago, and so that software or hardware doesn't have more modern drivers that don't use those old DOS methods of interfacing with devices. Similarly, some old software will likely rely on old SoundBlaster 16-bit drivers to produce sound, so Windows, to maintain backwards compatibility, keeps around and builds upon that old tech. This leads to, as you noted, a system of kludges that get put into place to squeeze performance out of hardware that has been obsolete since last millennium, but since the kludges worked and became a standard, they were built upon rather than thrown out, in the name of backwards compatibility, and this is probably not even the silliest thing that has happened due to maintaining this level of backwards compatibility (You may or may not have heard this, but since we're talking about Win10 and backwards compatibility, it's rumored that the reason Microsoft went from Windows 8 to Windows 10 is that so many old device driver installation disks would check for \"windows 9*\" as the operating system for their windows 95/98 drivers, that MS decided to skip that number in the numbering scheme to maintain compatibility for those install disks.). For people like us, it's second nature to want to try and optimize things as much as possible and get newer/better tech to handle things, but to the average population, there's very much a \"don't fix what ain't broke\" mentality, which has recently led to things like state governments desperately trying to find programmers who know COBOL and FORTRAN because their overwhelmed unemployment systems have been running on that for half a century and now can't keep up, and nobody knows how to update the code anymore since those languages haven't been taught in school for a good 2 generations now. **TL;DR sound is hard and we tried to do it too early, and now we don't want to break the early attempts by gutting the old bad stuff**"
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