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mkt18j | Why can’t you access a website if there’s too much traffic? How does that work? | Technology | explainlikeimfive | {
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"Well, can you move onto a highway that is already filled to capacity with other traffic participants? Just like you have limited bandwidth available to perform up- and downloads, every site's webserver has limited bandwidth available to perform up- and downloads. A sudden unexpected traffic spike will result in *nobody* being able to get enough data from the server to do anything useful. The other likely scenario is that some form of load-balancing or DDOS-protection service used by the website detects the traffic spike and immediately just shuts down access - \"Something fishy is going on here - *nobody* is getting in!\".",
"Imagine you’re at a crowded bar or restaurant counter. There’s one bartender or other service type person, but dozens or hundreds of patrons, each shouting their order and expecting prompt service. Like that, but digital. As with bars and restaurants, the answers are “more servers” and “more efficient processes,” which is how enormous sites like Google or Facebook seldom seem to have these problems (until they do)."
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ml08ab | Internet speed fixed by turning wifi off and on. | Whenever I have a slow internet connection on my laptop or phone, I just turn off and turn on the wifi settings on the phone or laptop. This fixes the issue most of the times. Why? | Technology | explainlikeimfive | {
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"Forces the router to clear all of the things gunking up its memory(cookies, trackers, temp files), downloads new firmwareid needed on reboot, and at the end of the day.... The poor thing needed a break ages ago. That hamster has been running non stop for....let's be honest here....even God couldn't say how long that thing has been waiting for a break.",
"Are you turning wifi off on the laptop/device or are you rebooting the router/wifi access point? If you’re doing it on the laptop/device, you could be reconnecting to the 5ghz band instead of the 2.4ghz band. There are also multiple channels that wifi can connect on. Sometimes a channel may be congested or suffering a lot of noise. Reconnecting to wifi can move you to a less busy channel. If you’re rebooting the router/access point, the other advice comes into play. Another thing that can happen is too many devices being connected and when your computer wakes up. It might find the pool of available addresses is consumed. This won’t be just slow, but nothing is working. You can have all your wifi bars and get nothing. Rebooting the router/access point can make all the current devices reconnect and your device gets an address."
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ml2i76 | How does this audio clip re-write itself | (rickroll warning) Play it once then play it again. URL_0 You might have to download it | Technology | explainlikeimfive | {
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"Technically speaking, it doesn't. What's going on is the original creator is exploiting a property of OGG Vorbis files whereby they can technically contain more than one audio file. This would never occur in the wild, and can only happen through engineering. By manipulating the serial number associated with the data, a media player can be tricked into playing another file \"inside\" the original. I haven't found a satisfactory explanation, but it appears that the media player gets confused when asked to replay the file, and jumps ahead in the internal file structure."
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ml2vfj | how does a computer trackpad or a phone screen tell if a finger is touching it or a brick? | Im asking because a finger will work, but no matter how hard you push with a brick nothing will happen. | Technology | explainlikeimfive | {
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"Basically, behind the screen is a big grid of tiny capacitors. As our finger gets close to them, the electrical current changes due to the interaction with our body. Our charge reacts with their charge. The system is optimised to respond within the ranges that we produce.",
"Modern touch screens are what are called *capacitive,* meaning they rely on a property called \"capacitance,\" related to the storing of electric charge. The glass on your phone is coated on the reverse side (away from your finger) with a thin layer of conductive material, arranged in a grid. Glass is an insulator, and your finger is a conductor; between the three components, a capacitor exists. The phone is capable of detecting the change in capacitance that happens when you touch your phone, and it can measure where that change is to report where you've touched your phone.",
"Human fingers have properties that bricks don’t, that’s all. It depends on the type of screen; older screens sometimes used pressure or heat to tell that you were touching it. Some old screens really could be fooled by a brick, others by a warm spoon. Modern screens work through capacitance. Capacitance is an electrical property; it’s measured in Farads. It’s a measure of how good something is at holding electric charge. Everything has capacitance, just like everything has a temperature. But some things have more capacitance than others. Human fingers are much better at holding electric charge than bricks. To your phone, it’s easy to tell them apart."
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ml3aq6 | Why can't Window's notorious "blue screens of death" be more precise with their diagnosis? | Technology | explainlikeimfive | {
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"The blue screen of death is as low level error. This usually means the computer has made a core dump, and an intelligent human agent (i.e. A programmer) is needed to figure it out. All the Computer knows for sure is the last thing it tried that failed.",
"I mean technically they are. BSoD at least with Windows 10, they almost always have a error code at the bottom of the screen. Which you can then search that error and it usually leads you to a common fix for that error or sometimes helps diagnose a hardware problem/defect. Or sometimes those blue screens can be complete false positives due to things like manually overclocking your CPU or RAM. I've had blue screens tell me my memory was bad, that Windows itself was corrupt. Yet when I clear the CMOS or default BIOs I then post into Windows no problem. So my best unintelligent guess is there are 1 billion things that could be wrong that even a single error code isn't enough. Yet if they give you this huge log of problems your average user is going to scratch there head with no idea of where to begin. There's no win win. Windows is still shit no matter how you look at it though. Each update adds nothing and seems to break something. PS. I cannot answer this like I'm 5. Sorry."
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ml6w2n | Is flying a plane hard? In terms of difficulty, is it comparable to driving a car? | Technology | explainlikeimfive | {
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"Cruising, banking and so on are comparable in difficulty. Landing it is not. The elements of flying a plane in a list of least to most difficult are: *actually flying the thing around *taking off *not crashing in a fireball when you try to land",
"Flying is as easy as riding a bike. It's taking off and landing that requires skill and practice. It takes about as much learning and practice as passing your driving test. But as an adult it's time consuming and needs you to revisit some of those learning skills you haven't used since school.",
"It really depends on what type of plane your are talking about and the level of auto pilot that your plane has. But regardless yes it is more difficult than a car: Controls: Steering is far more like a boat than like car only you have elevation as well. I'm sure other redditors will go into greater detail but your controls are far more complex and if you are relying on the auto pilot you need to understand how to read and program that specific autopilot exactly. You can't learn to fly a Boeing 737-400 and then go fly a Boeing 737-800 - you'd have to go specifically retrain (Boeing 737NG course). Navigation: In a car you are driving on a road with road markings and road signs and nowadays with extremely an useful GPS lady to guide you along. A huge part of flying is navigating as there's no signs up in the air to guide you along. And with weather conditions you have to learn to navigate by instrumentation alone. Radio: This is the reason I could never be a pilot - I do not understand what is being said over the radio and you cannot fly safely without having proper communication and radio discipline. You have to be listening closely at **all** times because there's no way to fly safely without listening out for air traffic control constantly. Safety: If your aircraft experiences any problem in air you can't simple pull over and open the hood. Therefore every single of aspect of flying involves safety checks and doublechecks. And these are not things that you can skip like when you pull your car out in the morning and you don't checked for punctures. You must follow specific checklists each flight in particular order.",
"Considering you have to deal with an extra dimension, that you have to keep moving forward at a minimum speed and that you have to deal with weather which unlike traffic, you can’t always see, (and because of some other stuff as well) I’d assume it’s likely harder than driving a car.",
"The actual flying is much easier. There is literally nothing to hit so you just need to keep the wings level and the compass in roughly the right direction you are heading. This is why planes have had autopilots for half a century already because it is one of the easiest things to do. Navigation is a bit harder because you do not have any signs saying where you are and where to go. Especially as the wind can push you around quite a bit. But with GPS this too have become quite easy, as with the GPS in your car. Landing can be an issue if there is wind. Especially if there is a strong crosswind and a narrow runway. But it may not be that much harder then driving a car. Where flying an airplane is much harder then driving a car is if anything goes wrong. In a car there is few things going wrong which prevents you from being able to pull to the side of the road and stop. You can just call a mechanic and have them deal with the issue. An airplane however, in addition to being much more complex, can not just simply land anywhere as soon as things go wrong. The pilot have to be the mechanic as well and diagnose the problem and find a workaround while they are flying the airplane. That means that they need to know all the systems and how they work together. They do have a big book of checklists for what to do in certain situations but there may not be enough time to look up the correct checklist and the exact problem they have may not be listed in the checklists. This is why even though airplanes have autopilots we are still very far from being able to replace the pilots. Computers are only able to react as they are programmed but the programmer may not have thought of absolutely everything that could have gone wrong."
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ml7xxn | Why are phone displays cheaper than monitors? | you can get a phone with a 1080 x 2400 120hz hdr10+ amoled display for roughly 250 euros and it's a phone doesn't just come with the screen it comes with all sort of sensors,batteries,CPU etc and if you want a 120hz (non oled) monitor you would have to pay about 170-220 usd which is roughly the same price of the phone that can do much more stuff (Redmi Note 10 Pro is the phone used as an example here) | Technology | explainlikeimfive | {
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"Monitors tend to be a lot more optimised for things like low response time, colour correctness and adaptive sync technologies. They also have to pay licensing fees for using HDMI and DP connections. The panel is also just physically larger, even though the number of pixels is the same, the factories producing these screens are of limited size, meaning the bigger the display, the less of them they can produce at once.",
"A phone display is 6 inches, a monitor is say 24 inches. That's 16 times greater area, so costs more than the phone screen. Also there is a much smaller market for 120hz computer monitors so they attract a premium. They used to be much more expensive!"
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ml8bnz | How exactly does a computer randomize a number? What exactly pick the output number? | Technology | explainlikeimfive | {
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"A computer never produces a truly random number, it produces something that's called a pseudorandom number. A good pseudorandom number looks random, but is actually a very very long repeating pattern (trillions and trillions long). A simple example is: 1. Pick a three digit number (the seed) 2. Square it 3. Take three middle digets - that's your \"random\" number 4. Plug that number back into 1 to generate your next random number. Where the randomness actually matters (e.g encryption), your computer tracks user inputs to generate entropy, this is a measure of disorder. It then uses this entropy as the seed for a pseudorandom generator.",
"There are two ways. First, a computer can use a complicated formula to generate a very unexpected number. This is known as \"pseudorandom\" (sue-doh-random). The formula will always generate the same numbers if it starts from the same place, but if you give it a random number to start with, it will generate a lot of numbers that are hard to predict. A lot of research goes into making good pseudorandom number generators. A very basic example: start with any number less than 37. Every time you want a random number, take your current number and multiply it by 7. Then, subtract 37 over and over until your number is less than 37. If you start with 12, you'll get 12, 10, 33, 9, 26, 34, 16, 1, 7... (It loops after it's done all 37 numbers!). Real generators are way more complicated, but you get the idea. But that's not very good if you're trying to use random numbers for security, is it? If you're relying on random numbers made by the computer as part of your encryption, then all an attacker has to do is guess you're starting number and they'll be able to guess all the rest by running the same algorithm. That's a problem. So computers have a second method- pulling randomness in from truly random sources. The computer hardware is full of random things. The hardware is all electronics and there's always some kinds of noise coming from electronics. You can listen to that noise and it's pretty random. The timing on when network messages arrive- lots of randomness. Also, you're pretty random and the computer can use *you*. It times how long between key presses and mouse movements- you think it's consistent but to a computer with a very fast clock inside it, there's a lot of unexpected variation- randomness! Many computer operating systems have what's called a \"random pool\". A big queue of bits that are filled up by random events happening and it storing them. When any program asks the operating system for some *real* randomness, the good stuff, it provides the front of that queue, slowly filling up the rest as it can.",
"Computers pick a seed number, for example, the current number of seconds since a certain time, and perform a sequence of mathematical operations on that number to produce a psuedo-random number. The computer then repeats this method on the new number. Since these number of seconds passed keeps changing, the next time the computer generates a batch of random numbers, those will be different. There are ways of having a computer choose truely random numbers, but that a little out of the scope of ELI5. You could read more here; URL_0",
"Fun fact: Our math teacher used the random function of our graphic calculator to pick students for his weekly homework grading. After one student was picked 8 times he realized that it was indeed not random. This method used the last commands which where calculated. After startup it was always 13 or 17.",
"A lot of the answers here talk about generating pseudo-random numbers purely from digital sources (i.e., using a 'seed' and using a formula to generate random numbers from there). But computers do have a way of generating truly random numbers, but that has to come from the analog domain. Some example include: * Read the temperature and use say the 10th digit after the decimal point. For example, if you read 21.1231412C, then the last digit is random. * Read a voltage on a floating wire and use the last bit. Again ends up being random. If you are using these random numbers for cryptographic purposes say, then there are techniques to further increase the randomness. For example, generate 3 numbers like this and use one of them to pick between the other 2. Things like that. There are standard tests to check for randomness which are sometimes contentious (some people feel they aren't sufficient to prove randomness) but if you go with these, I feel you are good for nearly any purpose other than maybe military level encryption.",
"John von Neumann Quotes \"Anyone who attempts to generate random numbers by deterministic means is, of course, living in a state of sin\"",
"There are two ways this can happen: * The computer merely acts as if it could generate truly random numbers, but in reality, it is just returning seemingly random (so-called pseudorandom) numbers. There are a number of [different algorithms]( URL_2 ) that can be used to generate these numbers - they usually start with a seed value (like the current time, or the number of pixels your mouse cursor travelled in the past few minutes), and then produce a deterministic sequence of fake random numbers. If the same algorithm is used with the same seed value, the sequence of numbers will be the same. * The computer contains a dedicated hardware component that uses a real world physical phenomenon to generate true random numbers. Most modern processors have such a component [built-in]( URL_0 ), but using it can be significantly slower than using the fake random numbers, and there are concerns about the security of such numbers - many cryptographic algorithms rely on high quality random numbers, and since hardware is very hard to inspect for backdoors, you have to trust the manufacturer. A slightly different way to generate random numbers based on physical phenomenon was [demonstrated by Cloudflare]( URL_1 ) \\- they use the live video feed of a bunch of lava lamps to generate high quality random numbers. In many cases, the output of a hardware random generator is fed into a pseudo-random generator, which is then used to produce the actual random numbers - if used correctly, this solves speed and trust issues, while the quality of the output is only marginally affected.",
"The closest ive seen for true random is what cloudflare does. They have a wall full of lavalamps and take photos of it peroidicly. Since the lava lamps are unpredicable this makes it extremly random. They then take the photos and turn them into incription keys soruce: [ URL_0 ]( URL_0 )",
"If I take the numbers 3, 1, 4, 1, 5, 9, ... they look seemingly “random” to someone who doesn’t know what the pattern is. A computer chooses a seemingly random pattern, usually by taking the millisecond that the random function was called. This is the easiest way for a computer to generate “randomness”. It then performs some arbitrary but hidden function to the number like square it, add 7, take the last digit and square root that, then take multiply by a new random number and then take the 3rd number. This appears random to the user but can never be “truly random”",
"A computer can only use a pre defined formula. Therefore the result will always be the same. What you see is pseudo random. As an input often the time is used. That number differs all the time. If you make a formula that makes small differences in input generate a big difference in output, it looks random, but actually isn't. Some organizations offer random numbers, for example generated based on the image of lava lamps URL_0"
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ml9pzj | Why can't we see the refresh rate of a screen unless we see it through our peripheral vision? | I was watching TV the other day and noticed when I'd look down at my phone I'd see the flickering of the TV you'd usually only see on camera, usually not visible to the eye. Why can our eyes only detect it if we're not directly looking at it? | Technology | explainlikeimfive | {
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"The edges of our eyes are good at super-fast responses, so they have a higher refresh rate\\*. This comes at the cost of less actual detail and color information, but like most things, our brains are good at filling in the missing detail. *Our eyes don't have a set refresh rate, it depends on a lot of factors."
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mlfzex | How are pirated movies recorded at such a high quality? | Technology | explainlikeimfive | {
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"Pirated movies are the same resolution as theater movies. Pirates aren't sitting in the back row with a camcorder. Most of these are data processed from the same data shown on the screen.",
"For early releases, High quality pirated movies are generally from screener versions of the movie (or any other pre-release version), Studios do ALOT of screeners and copies for celebs, friends, reviewers, critics, journalists, industry people, and awards shows. That is the studio sends out physical or digital copies of the movie for people to watch at home and during this process the pirate gets access to said movie, and makes a copy. Of course after this, once the movie is out in the public hands in physical form or on cable/streaming/etc., they have access to the general consumer version, and its trivial to make an exact copy. \"cam\" movies, which are low quality, generally are shot with a camcorder in the movie theater, and if they're lucky, they have a direct audio feed from the movie (yes that means someone at the theater is in on it), if not they just record the audio in the theater which is often pretty poor quality. Many cam recordings are done in theaters in Asia.",
"The other technique that you often see is 'Telecine', generally indicated in the title of the file as 'TS'. This technique uses a special camera and device to essentially scan the analog film strip to digital by photographing each individual frame. This can produce very high quality digital files depending on who's doing it and the quality of their equipment but a pure digital rip these days is still generally better. Fun side note: This is why so much stuff from before the '90s can be 'remastered' to look amazing today while there is a dark zone of early '90s - mid 2000's of stuff that's pretty bad. The earlier stuff can be up-scaled right off the original film, whereas early digital stuff was not shot in sufficiently high digital resolution to look good on today's AV equipment even though they were perfectly acceptable for a typical CRT TV of the time. While it's not impossible to upscale a low resolution digital video file, it's very hard and time consuming, usually involving techniques such as machine learning",
"There is no inherent reason why 'pirated' movies would be any lower quality than non pirated. You can buy a blu-ray disk, transfer the file to your computer and then upload that file.",
"In addition to what the others are posting, if Movie X has a July 1 release date, you can be fairly certain that it already has a BluRay release date sometime around October(ish). Those discs need to be mass produced (probably in some third-world factory), shipped globally, and stocked on retail shelves. That takes lots of time, so they begin manufacturing them sometime around.... July 1 or so. One of the discs accidentally doesn’t make it into the case, slips inside a pocket, and BAM, blue ray quality movie is now in the hands of a pirate.",
"Prescreening, releases for “awards considerations” very few is someone sitting in a movie theater with a bucket of popcorn and a camera hiding.",
"Simplest explanation: if you can see it, you can record it. Similarly: if you can hear it, you can record it. Some early-release movies (likely screeners, used by award companies to preview a movie before it hits theaters) have special software on the DVD that supposedly prevents certain recording software from being run. But capture cards throw all that work down the drain. All you need is a second computer hooked up to the player, and the DVD doesn't know anything's amiss. There may be some initial sound sync issues (if the pirate is a newbie), but usually not more than 200/300 milliseconds. So the second computer records, upload the file to the pirate bay, and Bob's your proverbial uncle."
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mlj6zb | how do small clock radio antennas pick up larger radio waves? | I'm guessing it's either my misunderstanding or it's because even though the radio brave is long the up and down amplitude of any radio station is very small in comparison to the radios antennae otherwise I don't understand how a small thing can pick up the entire range of the radio signal when it's larger. | Technology | explainlikeimfive | {
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"A radio wave isn't literally going \"up\" and \"down\", it's changing electric and magnetic field strengths. It's more like a sound wave (pressure rising and falling), not a water wave (literally up and down). The familiar graphic of two sine-waves at 90 degrees moving through space is a plot of field strengths, not the geometry of the electromagnetic wave. Ideally, you want the antenna to be about the size of the wavelength you want to detect but any antenna is going to pick up \\*some\\* EM waves that hit it and you can make up for under-size antennas, within reason, with good tuners, filters, and amplifiers on the back end."
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mlmtyi | What happens when you tune a radio? How do the frequencies change? | Technology | explainlikeimfive | {
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"The station frequencies don't change, but by tuning you are adjusting the receive part of your radio to become sensitive to a certain frequency you want to hear. Inside the radio are parts (capacitors, inductors and resistors) that allow this resonance frequency to be set.",
"The basic idea of most radio systems is \"frequency division multiplexing\", that is, different channels of information propagate through the air all at the same time but can be separated out from each other because each channel's information is confined to a different part of the radio frequency spectrum. So the general job of a radio receiver is to allow the user to control which part of the radio spectrum to \"listen to\", and to block out all the other parts, so (only) the material of interest can be received. We generally call this \"tuning\" on a radio, \"changing the channel\" on an old TV, etc. If you want to transmit radio information, you generally need to get a license, which will specify what frequency band you are allowed to use, how much power you can transmit with, and what modulation scheme you will use for your signal. Some licences are easy to get, while others are scarce, expensive, and/or require certification and training. Receiving radio usually requires nothing more than the equipment itself. The technical specifics of what the radio does to \"tune in\" a particular signal depend on what is being received. An old-style ham radio station will turn a carrier wave signal on and off rapidly to convey \"dots\" and \"dashes\" of the Morse code. An AM (amplitude modulation) radio station broadcasts a constant frequency carrier wave whose amplitude varies in such a way that it carries the sound or other signal. An FM (frequency modulation) radio station broadcasts a carrier wave whose frequency varies slightly; this variation carries the signal. There are many other schemes. Each requires dedicated circuitry that can lock on to the carrier wave of interest and then extract the original information (audio, video, dots and dashes, digital data, or whatever was sent). Radio is actually a wonderous and amazing technology, though we kind of take it for granted now. I imagine it must have revolutionized the world in the first half of the 20th century, allowing far-flung people to instantly connect with each other for the first time.",
"The wiggle trapper looks for and traps different speed wiggles. This is tuning a radio. The radio waves are wiggles. Y’all really know some genius 5 year olds if you think anything more complex will make sense.",
"Depends on the radio receiver, there are multiple designs. If you have an old radio with a physical knob, it likely changes the value of one or more variable capacitors, which will change the resonant frequency of parts of the circuit, like a filter or local oscillator. Often you get coarse filtering with a variable filter, then mix the incoming signal with the output of a local oscillator, before putting it through a much more selective fixed frequency filter. For more information search for \"superheterodyne receiver\" Though for modern devices, it's also possible to use software defined radio, where you have some RF front end, but put the signal into an ADC so you can use more general purpose hardware to do the heavy lifting.",
"The radio station mixes the audio (voice/music/etc.) with high frequency noise (the exact frequency is the radio dial number like 101.1) and sends it out over the airwaves. Your radio receives this mixture and if your're tuned into 101.1, the radio removes that frequency noise leaving just the audio for your enjoyment."
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mlmv8u | Why routers still take so long to power on in 2021? | I remember dial up connections taking at least 2 minutes to connect, plus the time it took for the computer to turn on. However, with broadband and fiber internet I'd expect everything to be faster. How come routers still take so long to stabilish a connection nowadays? | Technology | explainlikeimfive | {
"a_id": [
"gtmcrbs"
],
"text": [
"routers are basically running a lightweight linux (or whatever) computer inside of them and they need to boot up just the same."
],
"score": [
18
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
mlnbmn | How do dishwashers clean everything so thoroughly? | Technology | explainlikeimfive | {
"a_id": [
"gtme7gl"
],
"text": [
"It's a combination of high pressure hot water sprayed over and over and over again, and a detergent in the water that breaks down grease and food particles and dissolves them into a solution in the water to be drained away. Even without detergent, just the hot water spraying repeatedly for the cycle does the majority of the work."
],
"score": [
10
],
"text_urls": [
[]
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} | [
"url"
] | [
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|
mlo9by | how DDOS protection works | I went to a website and it redirected me to a page that said, “wait for up to 5 seconds to be redirected,” and then, approximately 5 seconds later, I got to where I wanted to go. When I looked how it worked, I got a whole bunch of technobabble that I couldn’t understand. What exactly is happening during those 5 seconds? How can it tell the difference between me, a legitimate user, and an attack? | Technology | explainlikeimfive | {
"a_id": [
"gtmks85"
],
"text": [
"Imagine you're calling a friend, but so are spammers. So many spammers so that every time you call, you get a busy signal and you can't talk to your friend. That's the DDOS. But a new guy says, call me instead and I'll patch you to your friend when I hear your voice so I know it's you and not some guy trying to sell her ephedrine diet pills. That's the protection. It's an intermediary that filters out bad traffic and only pushes the good traffic. There are a lot of methods on how they do this, usually requiring machine learning and/ or IP databases of known bad actors / previous denial of service traffic logs, etc."
],
"score": [
6
],
"text_urls": [
[]
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"url"
] | [
"url"
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mlonnt | What do “sound guys” at live concerts do? | Technology | explainlikeimfive | {
"a_id": [
"gtmn1bk"
],
"text": [
"There are separate mikes for each musician and singer. The sound guy adjusts the volume for each of them. They make sure you can hear the singer over the drums, that sort of thing. The volume you get into the microphone is based on how loud the person is plus how close the microphone is to them. So you don't want to just let them all play at whatever sound level they happen to get."
],
"score": [
4
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"text_urls": [
[]
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} | [
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] | [
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|
mlpum4 | Why are Magnetic Resonance Imaging (MRI) machines so incredibly loud? | ELI5: Why are Magnetic Resonance Imaging (MRI) machines so incredibly loud when they are operating? | Technology | explainlikeimfive | {
"a_id": [
"gtmu5te",
"gtnnhwh"
],
"text": [
"The magnetic fields used are extremely strong. To get good image the machines use a minimum amount of steel. Applying huge forces on plastic parts causes them to flex. Flexing them back and forth makes noises.",
"The MRI magnet is always on, whether it is making a noise or not! There is 2 magnetix parts to making an image with an MRI. The static magnet, eg the 3 Tesla, provides the base. The second part is called the magnetic gradient. This is a very small magnetic field on top of the 3T that makes small changes in magnetism along the length and breadth of the magnet. This is what allows the image to be formed. The gradient is turned on and off rapidly. This is done by pulsing a current through the wires wound around the magent. This current pulsing gradient causes the wires to oscillate and create this loud sound. For faster image acquisition, a higher current is passed and this causes louder sounds."
],
"score": [
13,
3
],
"text_urls": [
[],
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} | [
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"url"
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mlqsyy | How do DVDs and CDs work? How do they know what to play? | Technology | explainlikeimfive | {
"a_id": [
"gtn1cmr"
],
"text": [
"Let's start with describing a record player / phonograph. A record has a groove in it that has bumps and grooves in it. You can even see it here: [ URL_0 ]( URL_0 ) The movement of the needle in the record groove gets transmitted directly to the movement of the speaker. When the needle moves up, the speaker is pushed out. When the needle moves down, the speaker is pulled in. Do that very quickly and you can reproduce any sound. A CD is actually a very simple device that accomplishes the same thing, digitally. Just like a record, it's a flat disc that has a \"groove\" in it. But instead of the groove moving up or down, the CD has a pattern of holes that can be detected by a laser. The holes encode the same information as the record does, but digitally, using binary code. Think of it this way: suppose the position of the record groove could be \"high\", \"medium\", or \"low\". Those could be represented with dot patterns like \"dot dot\", \"dot blank\", and \"blank dot\". To be specific, a CD records a 16-bit binary number, once for the left and the right channels, and it does so 44,100 times per second. Those numbers are read by a laser and fed into a DAC (digital to analog converter) that can be used to move a speaker. A DVD is a lot more difficult. A DVD stores things in a similar manner as a CD, it's just more dense. It stores about 10x as many bits of data. But the idea is pretty similar. However, the actual interpretation of those bits is a million times more complex. While a CD has a pretty straightforward encoding of an audio signal that can be implemented by a pretty simple digital circuit, a DVD has a very complex encoding of a video. Decoding a DVD and turning it into a picture basically requires something as complex as a full computer. It's a very complex algorithm that takes a highly compressed digital code and uncompresses it to result in a series of full-color video frames that can be sent to a video screen. Plus the audio too."
],
"score": [
9
],
"text_urls": [
[
"https://www.factmag.com/2015/06/16/vinyl-record-needle-microscopic-video/"
]
]
} | [
"url"
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|
mluvfd | How does Internet archive work? | URL_0 On this website you can see old snapshot of particular website. How do they maintain it? They crawl the web and save copy of each website? | Technology | explainlikeimfive | {
"a_id": [
"gtnr9an"
],
"text": [
"Yep, that's literally it. They webcrawl constantly. With some internal logic that decides how often to crawl sites, how deep, and what images and similar do or don't get saved. And it's all stored compressed and decompressed when you want to retrieve a site. It's still tens of petabytes of data but it's manageable. They also apparently use Alexa Internet crawls (they're the the guys who rank websites) as well as their own to find sites to archive."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
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mlx0wy | How are internet speeds regulated by the service provider? | Technology | explainlikeimfive | {
"a_id": [
"gtnzy77"
],
"text": [
"It can be done in simple software settings in the routers that direct the traffic to you. They limit the amount of data to you. Extra data Thai is not forwarded can be stored in a memory buffet or simply dropped. That is if the speed is artificially limited and not because of a slow link."
],
"score": [
5
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|
mm0v5z | what is so different from console to pc that prevents game from being developed once and published to different platforms? | I keep hearing that consoles nowaday are basically computer, isn't the hardware almost the same? | Technology | explainlikeimfive | {
"a_id": [
"gtoiloz",
"gtoie5y"
],
"text": [
"It's like the difference in speaking English and Japanese. Coding languages are different for different platforms. That's why skyrim didn't come out on every platform at the same time but took years to come out on different platforms. They didn't have to start from scratch but they did have to program them to speak different languages of those platforms",
"Consoles are all identical. They have the exact same processor and the exact same graphics chips. This allows developers to build software that can be hyper-specific for that exact computing environment, taking a lot of short cuts and making a lot of assumptions. More general purpose computers don’t have that luxury, there’s a vast array of possible hardware setups that gamers may be using and accounting for them all requires more flexible and less efficient programming. These days developers usually do work with PC in mind as well, but in the past a lot of console exclusive titles took massive hardware-specific shortcuts that left the software extremely difficult to emulate on a PC."
],
"score": [
4,
4
],
"text_urls": [
[],
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} | [
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mm1bua | Why do rechargeable batteries lose capacity over time? | Technology | explainlikeimfive | {
"a_id": [
"gtovlj3",
"gtq0hlv"
],
"text": [
"Rechargeable batteries relies on chemical reactions to provide electricity, and the opposite chemical reaction occurs when you provide electricity **to** the battery. That's how they store the energy. Because of lots of factors (temperature, impurities, age and cycles, degradation of chemical compounds, physical degradation of the materials making the cell, etc) over time that reaction becomes more difficult, or there is less materials available for it to happen, and the result is you see a reduction in battery capacity.",
"* Rechargeable batteries produce electricity through a chemical reaction. * They also store energy by reversing that chemical reaction. * But there are also by products of both the forward and reverse version of the reaction. * Those byproducts are basically junk that take up room on the internal terminals on the battery. * They block electrons from flowing through the terminals. * Eventually too much junk builds up and not enough electrons can get through fast enough to maintain the voltage needed for whatever device your are powering."
],
"score": [
8,
3
],
"text_urls": [
[],
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} | [
"url"
] | [
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|
mm2bbr | (HACKING) How are bruteforce, dictionnary and hybrid attack still a thing when a server can just limit the number of attempt per seconds ? | Technology | explainlikeimfive | {
"a_id": [
"gtor0o9",
"gtov8bo",
"gtoqu4o"
],
"text": [
"Normally you don't attack the server, you manage to get a leaked copy of the database (which holds the encrypted/hashed passwords) and brute force that. Same goes with winrar - you don't try to break the encryption using winrar, you write your own program that tries to decrypt the rar password without using winrar itself.",
"Here's what happens. Someone runs a website called funnycatpics.whatever. They let you log in, with your email as the username, and a password. You just use the same password you use for everything. One day, funnycatpics.whatever gets hacked and their database gets leaked. It contains a lot of email addresses and password hash combinations. I pay someone money for a copy of that database. Now I have emails and password hashes. I start using a series of attacks to reverse the hash of the passwords and get the original passwords. I now have a list of email addresses and passwords. I start trying them on other websites. Lo and behold, the password also logs you into the hotmail account you were using, and from there I can get anywhere. It might also get into your online banking, or into many other accounts that are a lot more damaging from being exposed than funnycatpics.whatever.",
"Just because something can be done, doesn't mean it *is* done. Some people write bad websites that don't have this kind of limitation."
],
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14,
7,
3
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[],
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|
mmaqia | Why is everything in 3D modeling triangles? | Downloaded blender looking to try something new, gain a new skill. Fired up some YouTube tutorials, after a while I’m just left wondering why is literally everything made of triangles? I get that you can make other shapes out of all triangles, but why use two triangles when a rectangle would work just as well? | Technology | explainlikeimfive | {
"a_id": [
"gtq8vzr",
"gtqa3qk",
"gtq9e0j"
],
"text": [
"You already said it yourself, every shape can be made out of triangles. Most modeling is done using meshing, which is a large series of interconnected nodes (usually triangular meshing). I think a good way of picturing this is if you had a rectangle, and you needed to know the distance between one corner of the rectangle to the other for interaction purposes, there's only two ways of calculating this. The first is vector addition (unnecessarily long and arduous), and the second is triangulation which is much faster and more efficient.",
"Three points is the simplest way to define a flat plane in 3-dimensional space. This allows 3d models to be made, by defining various combinations of triangles. For solids, the interior volume is coded as ‘filled’, rather than empty. This giant assembly of triangles makes a ‘wire mesh’ that defines the geometry of the solid body.",
"Former game developer here, > why use two triangles when a rectangle would work just as well? And what is a rectangle, but two triangles? Triangles are the smallest geometric unit possible for a render engine. It simplifies matters that you have few foundational parts that you build everything upon. There are few advantages to using different fundamental geometries. There are volumetric geometries and renderers out there, they're principally used in engineering and 3D printing/CNC milling and machining."
],
"score": [
7,
5,
4
],
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[],
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} | [
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mmb93i | Why do otherwis reputable news agencies choose to host fake/misleading clickbait articles on their sites? | Technology | explainlikeimfive | {
"a_id": [
"gtqbmfs"
],
"text": [
"Because it makes them money. They are corporations, and corporations exist for a solitary purpose: make the stockholders money *NOW*."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
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|
mmjfj1 | Why does a computer screen appear brighter when viewed from above, and darker / of a higher contrast when seen from below the face of the screen? | for instance when you tilt the laptop screen too far towards yourself or too far backwards. Also, this doesn't appear to happen with a phone | Technology | explainlikeimfive | {
"a_id": [
"gtrx7vu"
],
"text": [
"The answer is, it depends on the screen. Electronic screens are complicated devices. Essentially we have many “pixels” that emit light of varying colors, but.... how do we do that? There are different ways to physically make a screen that does this, and each has different concerns. Some have small viewing angles, where each “pixel” is only directing light mostly forward. Viewing the screen from above, below, the side, ruins the brightness or color or some other aspect of the image. Other screens keep their color and brightness even when viewed nearly from 90 degrees. They would differ in price and materials. On a technical level, different display technologies can have almost nothing to do with each other. They all make a screen with pixels, but *what it’s made of* and *how it works* are different. Your phone might have an expensive screen with great viewing angle, because it’s small. But a screen like that might not work on a laptop. They could pull different amounts of power, weigh different amounts. They’re also completely unrelated to a CRT screen, which literally uses a massive electromagnet to bend a stream of electrons to only hit the parts of the screen it wants to light up."
],
"score": [
5
],
"text_urls": [
[]
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} | [
"url"
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"url"
] |
mmnw88 | - After Cookie consents became mandatory, some websites have suddenly added "legitimate interest" to their consent boxes, which are opt-out. What does "Legitimate interest" cover, and why is this allowed? | Technology | explainlikeimfive | {
"a_id": [
"gtsi3ph",
"gtswzvb"
],
"text": [
"\"Legitimate interest\" is literaly what is written in the actual law, so its hard to know what counts as legitimate and what not at this point of time. There will be lawsuits and court roulings that will make it more clear in the future, but for now, noone can say for sure. There are cookies that are clearly needed for the page to work, like if you login you need some kind of identification cookie.",
"Legitimate interest is one of the legal grounds for collecting and using personal identifiable information. It's also the least clearly defined. Here's an explanation from the UK's ICO: * the processing is not required by law but is of a clear benefit to you or others; * there’s a limited privacy impact on the individual; * the individual should reasonably expect you to use their data in that way; and * you cannot, or do not want to, give the individual full upfront control (ie consent) or bother them with disruptive consent requests when they are unlikely to object to the processing. Number 1 is pretty easy. #2 is not too hard. 3 and 4 are where it gets a bit slippery. So for example, in the Guardian website's section on legitimate interest it says: > We have a need to use your data for this processing purpose that is required for us to deliver services to you. > * Personalised ads and content, ad and content measurement, audience insights and product development with the option to opt out of this. Now some questions: do most people reasonably expect their personal data to be used to provide personalised ads? This is particularly true if that data is being passed on to third parties, which is allowed by legitimate interest. Are people unlikely to object to this processing? Given that this information and opt-out is in the same form as all their other cookie consents, is putting it on its own tab less \"disruptive\"? Is it not arguable more disruptive, making customers look at a second tab, rather than putting all information in one place? So yeah, things are open to debate, and the details law and good practice on this will only be developed over time."
],
"score": [
8,
6
],
"text_urls": [
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|
mmpowl | How come some new android mobile faces same age old problems like overheating, display issues, fingerprint issues again and again especially when they are from same vendor and with similar software too. | Technology | explainlikeimfive | {
"a_id": [
"gtsszx2"
],
"text": [
"Because sales are still high enough to justify releasing with issues. They have to release a phone each year to stay with the competition and this years phone was designed well before the last years model was released...... Isuues with this model are likey to be addressed in 2-3 generations, granting that they are small in number and nature and will not affect the bottom line."
],
"score": [
3
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"text_urls": [
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|
mmun85 | Why does water “destroy” electronics and how does waterproofing work to stop this | Technology | explainlikeimfive | {
"a_id": [
"gttmz29",
"gttmfqp",
"gttmjl9"
],
"text": [
"Water contains Impurities that make it conductive to electric current, when a piece of electronics gets wet the current flows where it should not go and can damage the components. Water only damages electronics that have a power source, electronic boards are sometimes washed during their manufacturing process with no damage as they are not powered at the time.",
"Water is conductive - it is a pathway for electricity to travel through. When you get water on an electronic device that is powered on / charged, you're introducing pathways for the electricity to go to places where it's not supposed to go, and that can damage those parts of the computer so that even after the water dries up, the electricity isn't going where it was supposed to go originally according to the original design of the part. Waterproofing just helps keep water out of parts where electricity/electrons are flowing. If the water can't get there, it can't open up those other pathways to fudge up the part.",
"Well, two things. 1. Water conducts electricity. This is a problem when you have small electronics that are wet because then the electric current no longer follows the correct paths, instead it follows the paths that the water creates... This is bad. 2. Water Corrodes. Most of the exposed components include various metals, which can rust and become unable to effectively transmit the required electrical current to operate certain components. These small components rely upon specific voltages to be supplied in order to function. Waterproofing effectively insulates these components from both the electrical conduction and the corrosion via various methods. Sometimes it's simply removing any ingress points, other times it's physically coating the electronics with plastic or other non-permeable membranes."
],
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8,
3,
3
],
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|
mn30gt | How are vibration functions created in electrical devices (cell phones, sex toys, etc.)? | Technology | explainlikeimfive | {
"a_id": [
"gtv49b9",
"gtv67un",
"gtv4i8s"
],
"text": [
"An electric motor turns a shaft with an off-center weight. This weight shifts the system around and round.",
"URL_0 behold! this is the rumble in a ps3 controller. it spins that heavy metal thing that's off balance at different speeds to create the vibration. haptic motors of modern consoles are much more complex but they follow similar mechanics",
"They have a tiny motor that spins an unbalanced disc. The heavy part of the disc wants to go to the outside, but has no counter weight, and tugs on your phone or toy ever so slightly."
],
"score": [
50,
25,
13
],
"text_urls": [
[],
[
"https://images-na.ssl-images-amazon.com/images/I/41mBj2Dm4aL.jpg"
],
[]
]
} | [
"url"
] | [
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] |
|
mn39eq | How do anti-piracy screens function, and is it possible to accidentally trigger them? | I've always wondered how anti-piracy screens work, and the chances of accidentally triggering them (an irrational fear i have). How do they work, and can you accidentally trigger them? | Technology | explainlikeimfive | {
"a_id": [
"gtv8jym"
],
"text": [
"It really depends on the console. For example, most the ones on the SNES work by checking to see if the cartridge had more SRAM than the game shipped with, since early copiers just gave the console enough that any game would work. For modern games with antipiracy, the detection method is usually just to try and detect if it's running under a Steam emulator or similar, or just for the dev to torrent their own game out modified to show the screen."
],
"score": [
4
],
"text_urls": [
[]
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} | [
"url"
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mn6obr | Why are printers so fussy? | Technology | explainlikeimfive | {
"a_id": [
"gtvviju",
"gtvsg5w"
],
"text": [
"Short version: capitalism. Why make a better printer if they don’t have to? Longer version: because involving moving parts means things need to be maintained, and that doesn’t happen. Comparatively, most other tech has very few moving parts. Easier to make reliable. In conclusion: buy a laser printer. Don’t fuck around with imitations. Future you will thank yourself.",
"Because technology and money Technology is fiddly when you have to be accurate to within a thousandth of an inch for years and years and years of low maintenance and abuse Money because the people who sell the printers actualy do not make money off of the printers themselves. They make money off of the ink and maintenance of these printers It is literally cheeper to buy a printer, use up the ink in an hour. Go back and get it replaced with a new one. Than it is to get more ink for it to work again. Monopolies suck"
],
"score": [
5,
4
],
"text_urls": [
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} | [
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|
mn8vmz | why it is only possible to insert custom code into some games but not others? | The two examples that come to mind are Mario World and Paper Mario, where custom code injections are frequently used by speed runners (credit warps) or even to write custom programs within the game like Flappy Bird which Sethbling did. What is it about the design of these games which allow for this type of manipulation, whilst in other games this isn’t possible? | Technology | explainlikeimfive | {
"a_id": [
"gtwmv74"
],
"text": [
"Sethbling explains it about as well as can be: URL_0 But the tldr is: - Games often contain programming errors. - Sometimes these errors make it possible to control contents of memory. - And sometimes the errors make it possible to tell the console to execute the contents of some memory you control the contents of. - The previous two things together let you corrupt the program in a controlled way, so it runs YOUR code instead of the regular code. This is a lot like a security exploit used to attack a computer, but used in a fun rather than malicious way. In Sethbling's case, those pixel-perfect object locations get turned into a list of numbers in memory. Those numbers are later (mis)interpreted as code. Seth worked with an assembly programmer who had studied the game's code to determine what numbers needed to be in memory to corrupt the game to behave like flappy bird. Then they came up with a complex way to force the game to store those numbers in memory using only regular game controller inputs (which is a difficult and unusual way to manipulate memory), and later on to execute the contents of that memory as machine code (which is also stored as numbers). When you enter the numbers, the game thinks they're x-coordinates where objects are stored. Later on when you execute them, it thinks the numbers are code that shipped with the game. Obviously you have to confuse the f*ck out of the game to make this happen, but if the game has the right bugs in it, it's possible if you work hard enough and study the game code closely enough. This takes a ludicrous amount of work. People have spent thousands of hours studying the code for the games Sethbling has hacked. In cases where people don't know how to insert custom code, it's because they haven't studied the game enough to find the needed bugs, or to figure out how to use the bugs in a controlled way just using regular game inputs."
],
"score": [
4
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"text_urls": [
[
"https://m.youtube.com/watch?v=hB6eY73sLV0"
]
]
} | [
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] | [
"url"
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mncnl2 | What is Edge Computing and how it differs from Cloud computing? | Technology | explainlikeimfive | {
"a_id": [
"gtwqssw",
"gtwspne"
],
"text": [
"Cloud computing is using computers in the cloud to calculate things, so you send all your input data to the cloud, it calculates things, and you get the results back. Edge computing is calculating a large portion of the necessary things already before uploading to the cloud, so that the amount of data (and thus both time and cost for data transfer) is minimized. A popular example is video recognition. Without edge computing, you would stream the full video feed of a camera to the cloud, where it would be processed to identify things. With edge computing, the device with the camera would process what it sees, e.g. whether there is movement at all, and then crop the picture down to the relevant part, and then only transfer the really interesting parts to the cloud for further analysis.",
"You're on the playground during recess and you're discussing with your friend what 14 times 95 is (as cool kids do). Your friend is pretty good with computers and could run back inside to Google what the answer is. (And this would still work even for harder problems!) That's pretty much guaranteed to get the right answer, but it's a pain for your friend to run all the way there, wait for a turn on the computer, Google it, and run all the way back. But your friend is also good at mental math and can multiply it out in her head. She might not get the answer as fast as the computer would, but it's still faster than running inside. The second case is like edge computing -- the \"less powerful\" devices immediately close to you, like your smartphone (or your friend, in my analogy), can do calculations and such directly so that you don't need to send the questions to the more powerful cloud (the computer inside the school). Even though cloud computing might get the answer faster, you still save time overall for relatively simple questions because you're not wasting time sending the data to the cloud (or running back inside). For real edge computing, you're also just saving on data costs since you don't need to contact the cloud at all. But if a question is super complicated, like 1454 times 7395, then now your edge-computing friend might not be able to do it in her head, so she'll still have to run inside and wait her turn to ask the cloud-computing school computer for the answer. That's why cloud computing is still important. Maybe for a medium-difficulty question, she doesn't have to run all the way inside and can ask a nearby teacher instead, which still takes time but is faster than going all the way inside. That's like another layer of edge compute. --- The other comment gives a pretty good real-world example of these problems (video recognition), so I won't repeat that here. :)"
],
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3
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|
mnew7l | how do wireless chargers that you just place your phone on work? | Technology | explainlikeimfive | {
"a_id": [
"gtx2d96"
],
"text": [
"They work with inductance. The charger has coils where a current is run through. This creates a magnetic field which can travel through air. A phone with wireless charging also has a coil in the back which picks up this field and translates it to an electric current. By monitoring the current and changing the field the devices are able to \"see\" and talk to each other."
],
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5
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} | [
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mnhnda | How did ancient civilizations discover and mine material ? | Mining and the subsequent purification process is very advanced, so how did so many ancient civilizations figure it out ? | Technology | explainlikeimfive | {
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"They studied their environment in detail, their lives depended on it. When they made a fire ring out of some rocks, then could explode and hurt them. Other rocks melted, and shiny metals were left in the fire afterwards.",
"The stone age was proceeded by the copper age. Copper and gold are two metals (I think also tin?) that appear in their metallic form on the Earth's crust. You can literally just find lumps of copper on the ground. And that's just what ancient man had discovered. Combined with knowledge of fire and curiosity, it's not a stretch that they would put lumps to fire and see what happened. We can't be certain how early man connected the dots, but the copper age started ~5,000 BC, and the oldest known copper mine is dated ~4,000 BC. It's not a stretch of the imagination that if you find an area rich in copper, and you want more of it, then perhaps you'll start digging in that area to see if you can find more. Because I mean, it could be fairy sprinkles, but hey, why not rule under the ground out while we wait for more? Oh shit, there's more in the dirt! No doubt they found ore in with rock... Onto the bronze age, ~3,000 BC, early civilization discovered some copper tools were harder than others depending on the source, likely from unintentional alloying with trace minerals found in the ore. If you're digging for copper, and you come up across lustrous minerals like cassiterite, a tin oxide, you might suspect a metal was involved. And iron and nickel alloys were also available throughout the bronze age, at the very least - in the form of meteorites! It was a rare, desirable, and durable metal. The bronze age had the technology to forge iron, but not smelt it from ore. King Tutankhamun was found buried with an iron dagger, likely considered, at the time, more valuable than any of the gold he was buried with."
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mnlzhy | Why does the light on my laptop charger stay on even once it's been disconnected from the mains? | Technology | explainlikeimfive | {
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"It contains capacitors. Your laptop charger is converting the incoming AC power to DC and stepping down the voltage. It contains various components to accomplish this, some include capacitors. Once you unplug it the capacitors will be discharging and will continue to power the little indicator light until they drain too low.",
"Typically that's just the capacitors, which are small devices used in electronics that can store an electrical charge. When you power them they build up a charge and keep it until you remove power at which point they start discharging. An LED has *very* lower power requirements, so a large enough capacitor can keep it powered for a little bit until the capacitor itself is fully discharged."
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mnpjwf | What is a firewall? | Are they even still relevant? What do they do? | Technology | explainlikeimfive | {
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"Imagine you live in a skyrise apartment building in a big city. The firewall is like the doorman. A random guy tries to walk into the building towards the elevators. The doorman is all, \"yo, hold up! Who are you here to see?\" If the guy says, \"I have a package for Mr. Barbacoa in apartment 666\", the doorman checks the inbound rules and finds that the resident at apt. 666 is, in fact Mr. Barbacoa and is accepting direct package delivery, so he gives the delivery guy a keycard that lets him go to Apt. 666 and nowhere else. The doorman also has outbound rules. A 5-year-old kid comes running out of the elevators, the doorman's dad reflexes kick in, and he rushes to block the kid from leaving without his parents. Now, imagine there was no firewall/doorman. A random person off the street could walk in and start checking all the doors to see if they were locked, then walk in and steal a TV.",
"They are still relevant. They block inbound or outbound connections to services that should not be publicly accessible. This reduces the chance that a computer is hacked, because services can contain bugs that can be exploited by hackers, or authentication that can be brute forced. An example is a database or file server. Also the first versions of Windows XP did not have a firewall enabled and internet users could for instance pop up dialogs with custom messages on random pc's through a messaging service that should not have been publicly accessible.",
"A firewall is a wall built out of fire-resistant materials – often concrete or concrete block –that slows the spread of fire between two sections of a building (or in the case of two adjoining buildings, to stop the spread from one to another.) You see them a lot in schools, apartment complexes, nursing homes, hospitals, etc. In many cases, building code will specify that a wall must be rated to withstand fire for a certain period of time, allowing for the evacuation and rescue of people and for fire crews to potentially save the building/portion of the building. They save lives, so they're definitely still relevant.",
"Are you asking in terms of computer networking, automobiles, or construction?"
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mnqtc0 | How does Noise Cancelling Work? | Technology | explainlikeimfive | {
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"Sound is a compression wave, which means it’s alternating regions of air pushed together and pulled apart, hundreds of times a second. If the headphones put out sound that pushes during the pulls and pulls during the pushes, adding them together ends up with no variations at all - so no sound."
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mo0fk9 | Why would an IPS display on a laptop be important if you won't be viewing it from the side anyway? | I understand why it's good for ultra wide monitors, but don't you look at laptops straight on anyways? Doesn't that deny the need for better viewing angles? | Technology | explainlikeimfive | {
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"Because IPS displays are better at more than just viewing angles. IPS displays are better than TN displays at color reproduction. If you want better image quality and don't need fast response times IPS panels are generally better.",
"Your tools should serve you, not the other way around. Do you enjoy constantly adjusting the screen to face you at the correct angle or do you sit perfectly still and never adjust just position? It's just more convenient, especially if you plan to watch movies with someone or even just leave the laptop *somewhere* on your desk without having to reach for it every time.",
"> but don't you look at laptops straight on anyways? Most of the time maybe, but definately not all the time....."
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mo1fze | What exactly happened to create a gigantic power jump between NVIDIA’s 900 series and 1000 series? Why hasn’t it happened again (yet)? | I was watching some benchmarks on YouTube a few days ago and the power gap between a 980 Ti and 1080 Ti was like 50-70% which sounds just insane. I think most power jumps in the 2000 and 3000 series cap out at 30-40% if I remember correctly. | Technology | explainlikeimfive | {
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"The process node dropped significantly, but we've stalled out since then You'll always see discussion about 14nm or 10nm as being an important change for a CPU or GPU, and it really is. That \"process node\" is roughly the width of the transistors so going from 14 to 10 lets you fit 2x as many transistors in the same area(0.7 long x 0.7 wide = 0.5 Area), but it also drops the power consumption to 70% of what it was before. This second bit is probably the most important for GPUs are the high end chips are constantly butting up against how much heat they can deal with. The GTX 980 TI was made on TSMC's 28nm node, and normally the next generation would be built on the next step down from this which would be the 20nm node, but instead they were built on a 16nm node which is 1.5 steps down. This meant that instead of a 2x increase in density and 30% reduction in power, it was closer to a 3x increase in density and 40% drop in power. The end result in this was that nVidia was able to go from 8 billion transistors in 600 mm^2 consuming 250W, to 12 billion transistors (50% increase) in 470 mm^2 (22% decrease) and still dissipate 250W. That's a 2x increase in density, and the smaller die results in a cheaper chip. This would be combined with any internal design improvements that improve their performance per transistor Unfortunately overt the last 5 years or so we haven't made a ton of progress shrinking transistors, things got really difficult. 14nm nodes came out in 2014, 10nm should have come out in 2016 but really launched in 2018 and is still having problems, 7nm was supposed to be operational in 2018 but companies are still struggling with yields and its pretty close to Intels 10nm which further confuses things."
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mo3qj8 | what does ping and jitter mean when we talk about internet speed | Technology | explainlikeimfive | {
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"Ping is a tool to measure round trip time (RTT). This is how long it takes for a message to both reach the other side and return. Many other posts are describing ping as one way time which is incorrect. The tool was named ping because the idea is similar to sonar. You send out a \"ping\". It travels out until it hits some thing and bounces back. The time between sending and receiving the bounce back. For those older than 5 who want to understand how to use ICMP to troubleshoot internet issues check out [This presentation on how to properly interpret traceroutes]( URL_0 )",
"Ping time is the time it takes for data to leave your computer, reach a destination and be returned. Many computers on the internet listen for a specific packet and it echos that packet back to the computer that sent it. Your computer measures the time it takes for that specific piece of data to get echoed back to you. That's the \"Ping time\". A single ping only tells you part of the puzzle. It's a single snapshot in time. The next ping could take longer or be faster. A high jitter means inconsistent ping times. Low jitter means more predictable performance. High jitter can indicate network congestion. Think of it like cars on a highway. High jitter is like start-and-stop traffic. Low jitter is like traffic flowing smoothly. It may be going fast or slow, but it's consistent. For viewing web pages, or scrolling Reddit or other social media services, jitter doesn't really matter. But if you're playing a video game that depends on a server, like Fortnite or Call of Duty, jitter can create quality-of-play issues. If you're streaming video, jitter can cause delays and stuttering in video playback.",
"Ping is how fast bits of messages arrive to you. If your friend sent you a stack of post cards in the mail, ping is what we call how long it took them to arrive. Jitter is how different those ping times are from each other. If the postcards all arrive the same day that's less jitter, if they arrive on different days, more jitter.",
"So the delivery man has a package, right? His name is Ping. It takes Ping 30ms to get from your computer to where he's going with your package out there on the internet, and return with the reply. Therefore your Ping is 30ms. The jitter is any external stops Ping has to make on his way. Construction zones, traffic, bad roads all lead to Ping sometimes taking longer than 30ms to get there and back with the package due to bad and unstable connections. Sometimes, Ping has to go through checkpoints or make other stops on his way, depending on where he's going, which can increase your jitter, and oftentimes your ping as well.",
"Jitter is more simply put the variability of latency(ping time). If you get pings consistently in the 30 millisecond range, but suddenly get a ping of twice that (60 millisecond) that’s 30 milliseconds of jitter."
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mo6t0l | Why does a “tilt-shift" effect make a picture look like a miniature scene? | Technology | explainlikeimfive | {
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"Imagine two scenarios: * A: a real-life city with tall buildings, photographed by a drone and * B: a miniature version of the same city, photographed from the same angle to look roughly the same as A. In A, everything would be sharp, because everything is far away from the camera. In B, you could focus on the top of the buildings, making the streets blurry, because the tops of the buildings are so very close to the camera (because it's a miniature and you had to go very close to it). Try it out with your eyes: hold your finger close to your eye and look at it. The stuff behind it will be very blurry. Now look at something further away. The stuff behind it won't be nearly as blurry. So what if you take a wide angle shot of a big, real-life city, and make the tops of the buildings sharp and the street blurry? Well, you can \"cheat\" and trick your mind into thinking that it's tiny. That's it. You can do this in Photoshop or you can do it with a tilt-shift camera. The two will result in a very similar effect in this particular example.",
"It comes down to the depth of field, which is the term for what is in focus in the shot. There is a single point where the image is focused on, and then the depth of field is how far in front of that point, and how far behind that point is in sharp focus, before fading to blurry out-of-focus look. One aspect of a camera lens is called the aperture, which is the size of the opening that lets light into the camera. The aperture can usually be opened or closed, to allow more or less light in, and also to widen or narrow the amount of space that is in focus for the shot. When the aperture is made small, the depth of field gets wider, so a small hole means that lots of your scene will look in focus. Conversely, if you set a wide aperture, the depth of field is much more narrow, which is how photographers get the blurry backgrounds on portraits. Another thing that affects the depth of field is how far away your focus point is. If you point your camera at a building half a mile away, focusing that far away will mean that you have a very wide depth of field, and almost everything in your scene will be very sharply focused. If you leave all the camera settings the same, but simply re-focus your shot on something very close, like a rock in your hand in front of the camera, being so close to you will make the depth of field very very narrow. The rock will be in focus, but things behind it will get blurry much more quickly. That distance factor is what causes tilt shift miniature photos to have their effect. Your mind subconsciously knows that to have a blurry foreground, and a blurry background, with a narrow strip of focus in between and a very quick transition from in focus to out of focus means that you're very close to something, and therefore, if you're very close to a scene, but it has things like buildings and cars and people in it, those must be very very small to fit into the frame, so your brain decides that it's a miniature. It's also worth knowing that this miniature effect is not the intended use of a tilt-shift lens. There is no \"wrong\" way to use a tool to make what you want to make, but the *intended* use of a tilt-shift lens is to help with things like architectural photography, where you want to stand on the ground and take a photo of a building without having some of it go out of focus because the top of the building is further away from you than the bottom of the building. So you can use the clever mechanics of the lens to adjust the plane of focus so that isn't always a flat perpendicular plane from you.",
"Simplified answer - because if you shot a miniature scene from close up it would look like this - blurry (out-of-focus) top and bottom, sharp (in-focus) middle. Your brain 'knows' this, so when it sees sees a picture with this effect, it 'assumes' it's a miniature. If you shot a real-life representation of that scene, you would do so from further away and everything would be in-focus which your brain would take as a sign that you're not looking at a miniature.",
"In every photo, the camera lens has a certain distance range where objects appear in focus, know as \"depth of field\". When taking a picture of large objects, say a mountain range, there won't be a noticeable difference in the focus of a mountain 3 km away compared to another 4 km away. This is because the depth of field is long and far away. When taking a picture of small objects, the camera's depth of field will need to be smaller and the focus will be closer. So if an object 5 cm away from the camera is in focus, another object at 15 cm will be totally blurry. This contrast of focus/blur within a photo is typical in pictures of small objects, and has become recognizable to us as a macro shot.",
"I wanted to add one thing that hasn't quite been fully articulated: Tilt and shift are two different functions that typical come together in one lens. Tilt is the ability to change the angle of the lens so that it's no longer parallel with the image sensor (which normal lenses are). Shift is moving the lens up and down relative to the image sensor (in normal lenses, the center of the lens is in line with the center of the image sensor). They can be used together or independently. The faux miniature effect you're asking about is caused by the tilt function in particular.",
"Classic [view cameras]( URL_1 ) have the ability to not only move the lens in and out for focusing purposes, but to tilt and shift both the lens and the film plane. This gives you the ability to adjust for perspective distortion and have variable focus fields in ways that an ordinary camera could never come close to producing. As one example, an ordinary camera has a focus plane which means that there's a plane in space in front of and perpendicular to the the camera's line of sight where everything is in focus, and anything nearer or farther than that plane will be progressively out of focus. A view camera, on the other hand, lets you change that plane so it's no longer perpendicular to the line of sight. So imagine you're photographing a scene where there's something to the left and near you, and something to the right and far away. A view camera would allow you to put both of those objects into focus. There's a [gallery on flickr]( URL_2 ) that contains some beautiful tilt-shift images. ---- Now a view camera can also be used to create the opposite effect. You could use the tilt-shift features to create an extremely restricted range of focus. By coincidence, when you use a normal camera to photograph miniatures, the camera will also have an extremely limited range of focus. Photographs of miniatures very often have the foreground and background out of focus whereas a photograph of an actual landscape would have everything in focus. Our eyes and brains have seen enough photographs of miniatures that we've learned to associate the limited range of focus with looking at miniatures. So now, when we look at a landscape that was photographed with the above-mentioned tilt-shift effect, it makes us think we're looking at a photograph of a miniature. It also helps a lot to shoot the scene from above, as a miniature would be photographed. ---- Finally, we come to the computer \"tilt-shift\" effect. This is nothing more than drawing a line through the scene (typically parallel to the horizon) and having the computer blur the scene progressively away from that line. And if the scene is animated, you can do other things to make it look like a miniature, such as speeding up the time frame or making the animation a little jerky so it looks like it was generated with stop-motion animation. There's [another gallery on flickr]( URL_0 ) for these images.",
"I wonder if someone who had never seen a photograph before would think the scene was miniature?",
"Because of how perspective works. When you look directly infront of you, you are actually only focussed on one spot, and the area around is blurry and unfocused. Whereas in a wide landscape view, you can see a larger area in clear focus because it's further away. So when you add artificial blur to the latter, it mimics how we would see it if it was right in front of us.",
"There's a concept called Depth of Field (DOF). This is the range of distances where everything is in focus. The closer things are to the lens of a camera, the narrower the DOF gets. The farther away they are, the wider the DOF gets. (Other things affect DOF but we're going to assume they're not changing) Tilt-shift effects are playing with DOF to make it narrow. This makes us think the things in the image are very close to the camera, and therefore very small.",
"Everybody’s talking about how cameras work, but the really interesting part of this is how your brain works: the reason this works is there is a whole visual language that exists nowhere in the world but looks perfectly natural to you because you’ve seen it your whole life in images captured by cameras. There’s no such thing as a “lens flare” in real-world vision, and a picture can’t convey the brightness of a real-world scene, but you’ve seen so many lens flares in pictures that you automatically understand a lens flare *means* brightness. The same thing is true for depth-of-field artifacts. A camera’s focus is not a whole lot like how your eyes experience focus in the natural world, but you’ve again got a lifetime of experience unconsciously learning what the focus characteristics of an image mean. In the past you’ve seen lots of pictures of things you knew were supposed to be small, and tilt-shifting manages to trip enough of the cues you remember from those pictures that it tricks your brain. Honestly I think one of the reasons 3D movies make a lot of people uncomfortable, even give them headaches, is kind of an “uncanny valley” thing. You can see depth, but the focus is still locked to whatever came out of the camera(s), so your eyes don’t quite know what to do. You can’t just focus on stuff in the background and then back on something front-and-center the way you constantly do in the real world without thinking about it. I remember some shots in *Avatar* with a shallow depth-of-field (i.e., a really blurry background) being really distracting because of that."
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mo9ds3 | What's the difference between path tracing and ray tracing? | Technology | explainlikeimfive | {
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"Path tracing is a form of ray tracing. Ray tracing is a family of rendering methods based on shooting rays to estimate the path of light in a scene. There are many similar, but subtly different, ways to actually use rays to to render an image. Path tracing is kind of the brutish one. The idea with path tracing is that when a ray hits something, you just generate more rays going out from the collision point and use them to estimate where the light that hits this point is coming from. So you effectively trace the path of a bunch of photons in the scene (although usually in reverse, starting from the camera). The nice thing with path tracing is that the results are always physically perfect, so they look exactly like the scene would look in reality. The problem is that getting good results requires tracing billions or trillions of rays, which is really really slow."
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modv0j | How can my phone contact emergency services, despite signal? | Technology | explainlikeimfive | {
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"Carriers, by law, are forced to accept an emergency call from any device capable of communicating on their network (even if it's not a type of device whitelisted for their customers), regardless if the caller is a current subscriber or not For example, if only a Verizon-owned tower can be reached by someone who doesn't have any active service at all, the emergency call will connect through that Verizon tower.",
"Emergency servic calls can be routed through any and all networks, even from different service providers. So if you're in an area where your Service Provider doesn't have coverage, you won't be able to make normal calls, but if other SP have coverage emergency service calls can be routed through their Network"
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moimk2 | How exactly do solar panels work? | Technology | explainlikeimfive | {
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"Solar panels are made of many photovoltaic cells linked together. Photovoltaic cells convert sunlight into electricity. They do this by allowing little particles of light, called photons, to knock electrons free from atoms. When these electrons are knocked free/separate from the atom, this generates a flow of electricity. How this works is the photovoltaic cells are made of semi-conducting material (like silicone. Semi-conducting refers to how well the material conducts electricity. We say “semi” because it isn’t the best conductor nor is it the best resistor, it falls in between, which makes it more versatile). This semi-conducting material is stacked on top of each other in two layers, which together are called the photovoltaic cell. Each layer of the semi-conducting material is given an opposite electrical charge (one positive and one negative), which produces an electrical field (did you ever do the experiment in school as a kid where you took two magnets, one positive and one negative, and tried to make them touch but they pushed back? That was because of a magnetic field. Electrical fields are the same, but with electricity). Now that we have an electrical field, the sun gets added in. Light has a physical form, called photons (light particles). The photons hit the solar panels and the photovoltaic cells that make up the solar panel. When they do this, the photons don’t just go through the panels, instead they knock electrons free of the photovoltaic cells. These electrons get caught in the electrical field and pushed out of the junction of the semi-conductive material. These electrons get forced by the electrical field to conductive metal plates on the side of the solar panel. They are then transferred to wires, at which point they’re like any other kind of electricity.",
"Photovoltaic cells have a sandwich of semiconductors that when light hits them it knocks electrons from their atoms, which generates an electric current."
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mok2rh | Why are micro waves used to heat up food? | Why can't radio waves, infrared waves, or visible light waves be used to heat up food in microwaves? Why are micro waves preferred? | Technology | explainlikeimfive | {
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"This is actually a fairly complex mechanism that many get wrong. Most think it causes vibrations in the water molecule but it doesn't! Instead it causes semi rotations due to the dipole geometry of the water molecule (dipole momentum). Microwave frequency is too low to allow a full rotation of the water molecule so it turns the water molecule about half way in which the water molecule then turns back the other way. This causes intermolecular friction with neighboring molecules and thus heat! So put simply in another way: the microwave causes a little half spin of the water molecules and this creates friction between neighboring molecules.",
"The how has been pretty well covered. The discovery of it is pretty interesting though and deserves a mention. Heating food with radio waves was actually first done with shortwave radio shortly after we developed vacuum tubes that could generate shortwave radio. The more practical heat food with microwaves effect was first discovered by a radar tech working on microwave radar (also shortly after the magnetron was developed that have us the ability to generate microwaves) Dude noticed some chocolate had melted in his pocket. Little bit intimidating when you also note that -he- was getting microwaved a bit. After that he deliberately pointed the thing at some popcorn, and exploded an egg too. After some further tests pointing the microwave radar into a metal box to trap the microwaves with some food they then had what is essentially a modern microwave.",
"Microwaves *are* radio waves. You can use a different band of radio waves, but producing and containing them cheaply and safely at such high power gets more difficult. You also lose penetration depth with higher frequencies - the inside of your food stays cold. This worsens further with IR, visible, and UV, where only the very outer surface is heated. Cooking food in an oven is similar to \"IR cooking\" it."
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mola8j | Why does taking photos using the Rule of Thirds produce much more aesthetic images than centering the object? | Technology | explainlikeimfive | {
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"The first thing that comes to my mind is movement. Having the subject framed at one of the thirds intersections keeps the viewer’s eyes moving around the photograph. It’s not stagnant. Some photographs are able to be captivating without using this “rule”, but understanding the dynamics of shape, form and movement in a still image generally help when breaking the rule successfully. I’m a professional photojournalist if it matters.",
"I suspect it triggers something about how we look at faces. When dealing with other people, we have evolved to pick up the tiniest hints of movement in someone's face. Especially, the eyes and the corners of the mouth. If you look at an average face, eyes and corners of the mouth are pretty much at the intersections of the thirds, vertically and horizontally. Wouldn't surprise me, if we have a tendency to look more closely at these thirds points in any visually perceived object, and if we find something of relevance there, it clicks."
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mopkc7 | I hear about SAAS all the time but what is SAAS 2.0? | Technology | explainlikeimfive | {
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"SaaS \"1.0\" are largely fixed solutions, the premise of SaaS \"2.0\" is that they will let you create tailored solutions on top of a provided base, along with the tools you need to tailor it. Software as a Service (SaaS) \"1.0\" is where a company provides a useful service to you (or more likely an organisation). This could be something as simple as office tools (a word processor, email, etc think Office 365) or an accountancy system or a network DMZ, for example something Akamai provide. In each of those cases you get what the vendor gives you with little tailoring. In SaaS \"2.0\", which is just a pundits thought experiment, the idea is that you get a toolkit to build your own bespoke SaaS tailored to your needs. If you want an accounting system that handles single, or triple, rather than double, entry you can build it. Need something to to handle UK-US customs and taxes you can do that."
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moqyjr | when a website temporarily "goes down," what is actually happening? | Technology | explainlikeimfive | {
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"Many people think of websites like a movie theater, where if you want to see a movie (website) you just go to the theater number (web address) and the movie is being shown there to everyone watching. However, it's much more like the early Netflix model where your movies came in the mail. You request a movie (http request) and its delivered to you (http response). There are lots of reasons you cant get your request met. Maybe there are too many people requesting that movie, the movie is being updated (and for some reason they didnt want the old version to be sent out on the meantime), or maybe your request isnt getting through in the first place. It's also possible that the place that ships the movie to you (a physical server somewhere) has lost power (although this is getting less common as it's really easy to have a backup server in another region). Sometimes if there are large updates to a website, sites respond to all requests with a simple webpage that explains that there is a outage.",
"basically somewhere between the servers and you the stuff running the website stops working Can think of it like, \"why did my car stop moving\" - that's not enough to tell you why, could be gas, wheels, engine, transmission etc. For a website it depends on the website architecture but essentially the same idea, one or more of the components required to get the site to your computer aren't doing what they need to be"
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9,
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mov7mw | When you downsize a pixel based image, how are the pixels that are to be removed determined? | Technology | explainlikeimfive | {
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"text": [
"That depends on the downsizing algorithm used. Generally where many pixels will be squashed to a single pixel most methods will in a manner find the \"average\" color of the colors being merged. good downsizing algorithms will have more tricks to determine how much weight to put in to different things to make it look the best.",
"Typically a 2d interpolation algorithm is used. The general process is to take each pixels RGB value and pretend that it's a smooth function as opposed to an array of discrete steps. At this point you have a 2d function defined over the domain of the image. You then determine the new size, with a new number of pixels, and calculate the RGB values of the new pixels based on the smooth function that was created by the interpolation algorithm."
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12,
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mowrta | Why do manufacturers still put power supplies on the plugs instead of having a cord with the plug on it come out? | Why are companies still [making plugs like this]( URL_0 ) where the plug is built directly into the box when they could easily make a [design like this]( URL_1 ) where the plug is attached to the cord? Those big box plugs just take up space and make it hard to connect other power cables in the vicinity. | Technology | explainlikeimfive | {
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"Plug-mounted converters are cheaper to make where practical - it's a whole other cable and connector that is removed from the design. Switched-mode power supplies are coming a long way in removing the bulk from these plug-mounted adapters - many USB phone chargers are barely larger than a normal plug. It's mainly the legacy transformer-rectifier designs that are bulky, or particularly high power supplies.",
"Cost. The second design requires an additional cable and plug compared to the first. You'll see the wall wart design more often for cheaper electronics where they are very sensitive to price."
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moyobx | Why do certain types of images get gradually worse in quality after being repeatedly downloaded and respread? | Images like .jpg for example | Technology | explainlikeimfive | {
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"gu7hb22"
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"text": [
"Your premise is wrong; images don't get worse by being downloaded or being re-spread. When you download or share a file, you are sharing an exact copy, barring the rare case of data corruption. Images compressed using a lossy compression algorithm like JPEG will degrade over time only if the image is constantly being re-encoded. Different online services may do that automatically to ensure their images are in a consistent format (file type, file size, resolution, dimensions etc) or some users may do it manually (especially if they are cropping it, or adding custom bits of text, like they would with a meme). But that's an artefact of how people or online services change the image on purpose, not a side-effect of it being downloaded or shared."
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7
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moyun9 | why tape doesn't leave sticky residue on itself when wrapped in itself | Often when I peel tape off of something there will be some stickyness where the tape was, but on the roll of tape the back of the tape where tape was once stuck onto isn't sticky at all. | Technology | explainlikeimfive | {
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"The tape material is coated on one side with something the adhesive doesn't adhere to very well. Think a piece of paper with wax on one side, glue on the other.",
"Okay, so the smoother a surface is, the less things will stick to it. Think of a rock climber and the handholds he has. Less handholds, less grabbing. For this reason, they rough up surfaces before applying glue, like patch kits for bicycles, or tile floors. It helps if the glue has more to grab onto. So when they make masking tape, they take a paper roll, and wax one side to make it smoother, so the adhesive won't grab very well. The other side stays rough, so it grabs just fine. As it rolls around itself, the sticky side always meets the smooth side. Of course, if the roll is left in a hot place, it all melts together, and the whole roll DOES get stuck to itself."
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moyxh4 | Why does high volume damage speakers. And why are TVs designed with the option to go so high if it damages them | Technology | explainlikeimfive | {
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"Speakers work by moving a cone back and forth with a magnet which creates sound waves in the air. To make something louder, you need to move the cone a bigger distance. Rapid movement over bigger distances can physically damage a cone. Also, the higher you go with volume, the more distortion which can also cause damage. The reason TVs have settings beyond the damage threshold is that input 'line level' us not normalised, so some inputs are quieter and need more amplification.",
"High volume does not damage speakers. Too high of a power does. Speakers should be rated for more power than the amplifier can put out. If it's even something modest like 2 times more power handling (speaker) than power output (amplifier) it's almost impossible to break the speakers. If you have undersized speakers / oversized amplifier, the problem doesn't show up when the volume is low. Power output goes up with volume, but if the amplifier runs out of power before the speaker reaches its limit, speakers won't be damaged. There's a secondary problem where clipping causes excessive high frequency power. All of that goes to the tweeter, but the tweeter is too small to handle the excess. Using an appropriate sized speaker, and turning it down if you hear anything distorted mostly prevents it from happening. (It sounds bad when there's risk of damage.)—You can also prevent the problem entirely by using a low power amp. If your 100 W speaker has a 10 W tweeter, it would be impossible for a 10 W power amp to break it. But that's extremely impractical.",
"Not sure if this is exactly your issue, but speakers in the low/mid range typically use a voice coil actuator - it pushes and pulls air when an electric current or voltage is applied. If that were to exceed a practical input voltage range, the actuator could be damaged by exceeding a physical travel range. High frequency speakers (tweeters) typically aren’t voice coils but some surface vibration that can operate faster (but not push more air). Not sure if those are “blown out” often. With a nominal range of power input and control voltage/current, they would “filter” out the out-of-range frequencies using an electronic filter (crossover) or just not be able to reproduce them.",
"Speakers can be damaged by physical over exertion or heat related melting or changing shape. The electricity from the amplifier goes into a thin wire wound in to a cylinder shape. This is an electro magnet, called a voice coil. If too much power is applied, the thin wire will heat up. This can break the wire, thereby breaking the circuit. It can also cause the cylinder to warp, which means that it no longer fits correctly in the small gap it has to fit in. The voice coil pushes and pulls a surface that in turn moves the air. If the surface moves too far it can tear. TVs can go loud enough to break them selves because the program you are listening to might be quiet and the TV allows you to turn it up enough to compensate. If you leave the volume set high but then play a louder program, it may be loud enough to damage the speaker. Usually the user hears unpleasant distortion and turns the volume down. It is possible for manufacturers to build systems that aim to protect the speakers. Eg, limit the voltage that goes to the speaker",
"Every conventional speaker has three parts: a frame, a voice coil, and a cone. The coil is essentially an electromagnet with a permanent magnet at its core. Passing current through the voice coil sets up magnetic fields in it that are either amplified by the permanent magnet, or oppose to the permanent magnet. These magnetic forces move the voice coil in and out at the same frequencies as the audio signal applied. Regardless, the design of the speaker sets firm, physical limitations for how far in or out the voice coil is allowed to move. If it moves father, the cone, which is attached to the voice coil as well as the frame, will be torn. The cone is made of thin material, like paper or polymer, and so too much force, or force in the wrong directions, will tear it. Once the speaker cone tears, that's it. It's trash. There's no meaningful way to repair a torn speaker cone in a way that will have it regain its former ability to reproduce sounds from the audio signal input to the voice coil. Much like the adage, everything is air-droppable at least once, every speaker is capable of a voice coil excursion of three feet… at least once. However, whether it's material dropped out of an airplane or a speaker after the voice coil has been propelled three feet from its resting position, there is no guarantee that it will still be functional. As to TVs with audio amplifiers capable of blowing out their own dinky little excuses for speakers, most TVs also have provision for attaching a so-called soundbar along their lower edge. The speakers in these soundbars are more robust than the built-in speakers. Poor design choices lead to passive soundbars, which do not have their own amplifiers built in. Therefore, the audio amps in the display itself must be powerful enough to drive these larger, external speakers, even if it means having to implement software limits to try to restrict their output when relegated to only driving its own internal speakers."
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mp20ev | Why does streaming videos in 4K on platforms like HBO or Netflix always have such great, seamless quality but streaming a YouTube video at high quality always needs long buffer times and still sometimes has pixelated quality? | Technology | explainlikeimfive | {
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"Netflix doesn't have to deal with timelines for when videos go live. They can spend the time and effort to process the video for quality way ahead of time. I mean it's not like their library includes things that were produced and/or released TODAY. Even if it was released today, that's usually netflix's decision so the video was likely processed a week ago. Whereas youtube takes uploads from anyone at any time and videos are expected to be viewable within a few minutes, maybe an hour at most on an average day. Advantage, netflix. Also youtube content is uploaded by all sorts of people. Professionals and people who do this as their main income will tend to be better at it but the quality of the video you send to youtube matters. If it's crap, youtube will show crap. That's the creator's fault, not youtube's. Advantage mostly to netflix as their videos are professional across the board. As for buffering, that's a risk vs reward thing. Longer buffer times means the player loads more video before it starts playing. If there's an internet connection problem it will have more data downloaded already and have more time to cope or wait out the problem than if it hadn't. So there's the risk Netflix is taking, but on average it works out pretty well."
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mp3a4g | Why do movies/TV shows show credits both at the start and end of said show/movie? | Not gonna lie, I've been wondering this since I was about 5 | Technology | explainlikeimfive | {
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"text": [
"It used to be that all the credits were shown at the start of a movie but who wants to sit through 20 minutes of credits before the movie starts? So nowadays generally only the big names get credited at the start and everyone else at the end. I believe George Lucas paid a fine to one of the guilds he belonged to when he made Star Wars because he put the credits at the end when the guild rules were credits at the start. He then quit the guild.",
"The ones at the start are generally the “important” people (director, cinematographer, producers, actors), whereas the ones at the end list the full crew for each department. That doesn’t really explain why, per say, but that’s just generally how it is, as it’s not the same credits you see. (I work in film/TV, and would only ever be seen at the end credits 😆)",
"Union contracts. And there are a lot of different unions involved with making a production. Here’s a good starter article about how things are laid out: URL_0"
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mp92qm | Why do people in videos seem to walk faster than normal? | Technology | explainlikeimfive | {
"a_id": [
"gu8dxgl"
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"text": [
"If you are talking about old videos (1920s), they were recorded with a much lower fps because of technology limitations. So, the theaters often played them at a faster rate than they were filmed to avoid stuttering, and this became the norm at that time."
],
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4
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|
mpbyiv | in computer hacking, what does it mean to get in via a back door and how does it work? | Technology | explainlikeimfive | {
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"text": [
"Lots of things have a normal way to get in, where you just are a user and log in and use the site, that would be the front door. For a lot of reasons a lot of things also have numerous other ways other things get in, like special code for the advertising bots, or debug stuff that programmers use, or admin tools, or testing software, or a million other things. These often are not as well tested or protected as the \"front door\" so hackers get in using them. Basically it's an intentional way to get into something, but not the one intended for you to use.",
"Did you ever learn the \"Konami Code\" for video games? On some Nintendo games, if you hit ↑↑↓↓←→←→BA **START**, you would get a bunch of extra lives and power-ups for the game. This was invented so the game developers could test their game without needing to be exceptionally skilled. This is an example of a back door in a computer system. Other networking systems will sometimes have these, usually in the form of administrative tools. A common practice in an organization I used to work for was the \"Troubleshooter Account.\" This was an admin account that anyone troubleshooting computers on the system could use. Of course, this was a major security vulnerability as well -- if a worker stopped working for that organization, or even just the department that did computer work, they still had access to everything in the network. In other cases, they exist for the same reason as the Konami code: developers put them in so they could work with all parts of a secure program.",
"Say you live in a house on a busy street. When you leave your house, you lock it. You're the only one with a key. You don't want anyone to get in unless you use your key to allow it. But there may be circumstamces where you want a backup solution. What if you locked your key inside? What if someone you want to be able to enter your house arrives, and you're not there to let them in? To solve this, you devise a brilliant plan. You'll leave a spare key under the doormat by the the door behind your house. A clean backup strat to get you in in a pinch and easy instructions you can grant to trusted parties that you can revoke at any time. Sure, it would be devestating if someone you didn't authorize found it, but someone would have to jump through the mental hoops of going around back of your house, moving the doormat, and finding the key. And the sad fact is, some clever people DO manage to take the time to scope things and figure that out. In the real world, we call them burglars. In the digital world, we call them hackers."
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mpgrc4 | How do parental filters work? Is there a list of all adult content sites? Does someone manually add them, or is it automated? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"It depends on the system used to monitor the adult sites. Some are manually added by the parent(s) themselves, some are automated to block known adult sites (or games, or whatever else needs to be blocked), others are a massive list that's added to manually. It can also depend on where you're monitoring, too. For example, school districts can have district-wide filters based on an automatic list, with individual schools adding their own rules into that."
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5
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mpnuo0 | what makes programming languages like go and rust memory-safe and c++ not? | Technology | explainlikeimfive | {
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"text": [
"In old languages like C and C++ it's up to the programmer to not make mistakes. For example if you type: int a[10]; a[16] = 0; The first line gives you an array (like a group or collection) of 10 integers/numbers. The second line, you set the value of the 16th integer to 0. This doesn't make sense, you asked for 10 numbers, you can't set the value of the 16th number. In languages like C and C++ the is called undefined behaviour. What will happen, nobody knows. Your program might crash, it might act strangely, or it might work perfectly fine for 10 years and then start crashing. Newer languages came along, and the designers said, people make mistakes, the language shouldn't just allow it, but help them see their errors. So in a newer language, if you type a[16] = 0; before it sets the value, it checks if position 16 is even valid. If not, it throws an error. Otherwise it sets the value. This check takes time, so people who like high performance have stuck with C and C++. The other issue is sometimes the programmer doesn't know how much memory is needed. For example, if you are creating an image editor, you don't know the size of the image the user will open. So you need to wait until they open it, look and the width and the height an the request enough memory to hold the image. Something like: auto image = new Pixel[width * height]; and then when the programmer is done with the memory: delete[] image; Again, it's up to the programmer to not ask for a pixel at a position outside of the image. Or to ask for a pixel after they've already deleted the image. Go takes a different approach. The programmer still has to ask for the data for the image, but they don't have to worry about deleting it later. Instead, the language, every few milliseconds, looks at all the memory being used, and can see if the image data won't be used again and deletes it for the programmer. The downside here is this checking takes time, and the program will be using memory it no longer needs, but go hasn't noticed it can free it yet. Most programmers use safer languages now, they are a little slower, but it's not an issue for most things, maybe other than operating systems and video games. So Rust came along and took a different approach. It's goal is to be fast and safe. Also, if you are going to write an operating system, you need to be able to poke around in memory in weird and unsafe ways. So it has unsafe blocks, you can write all you weird and crazy code in there and do anything. The rest of the program will be safe. The advantage here is if you do have a crash, you only need to look in the few unsafe spots and check them carefully, compared to C++ where the crash could be anywhere.",
"Languages like C++ and C allow you to handle memory allocation yourself. This means you have the power of managing when an object gets created in memory and when it gets destroyed. It's a wonderful thing, since it gives you complete freedom. It's also a curse, because you must make sure that you know what you're doing. If you allocate memory for an object and you never free it, you create a **memory leak**. If you do this repeatedly (even worse: in a loop) you can easily hog memory until the program crashes down with the rest of the system. If you free memory for an object, but you keep pointing to its old location in memory, you created a **dangling pointer**. Trying to access that means crashing the program, in the best of cases. Trying to deallocate the object a second time results in a **double free** - again, with dire consequences. If you allocate a certain block of memory for an object, but you keep reading well past it, you end up accessing memory that you shouldn't. This can result in more than crashing your program: you can pave the way for the next vulnerability to be exploited by a malicious user (**buffer overflow** attack). In C++, and even more in C, this is dangerously easy to do simply by operating on strings and forgetting to put a terminator character at the end. Higher level languages don't allow you to this do kind of damages. They employ boundary checks to avoid buffer overflows. They might use a **garbage collector** - you can see it like a little program inside your program, constantly overseeing memory and automatically freeing memory when it's no longer used. In short, they take away the power to manage memory yourself - depending on the cases, this can come at a cost in terms of performance. But in exchange they give you the safety of not shooting yourself in the foot.",
"The \"compiler\" is a program that converts a language that's relatively easy for people to read like Go/Rust/C++ into a language that the computer reads, which is called \"assembly\" or \"machine code\". (There can be some other steps in the process but we'll stick with the simplest answer.) The C++ compiler doesn't enforce a lot of rules. You can write code that is very obviously flawed and it won't complain. This is a blessing and a curse. It means very clever C++ developers can do ridiculous things and yield performance benefits for it. It also means developers who aren't as clever as they think can create serious problems. Rust and Go have more \"discipline\". They have rules about how you are supposed to use memory. If your code breaks those rules, the compilers refuse to convert your code to machine language. Sometimes the bad stuff happens in C++ because the code makes the status of some memory ambiguous. A stricter compiler's response to ambiguous memory use is to treat it like an error until you remove the ambiguity and prove you're following the rules. Imagine you're playing the Shell Game with someone. This is the game where a ball or some small object is placed below one cup, and several identical cups are placed next to it. Then, the person running the game slides the cups around to try to disguise where the ball is. If you pick the cup with the ball, you win. C++ is like a version of that game where anything goes. The person might spin the table around and, while you're not looking, take the ball away so there's no way to win. Rust and Go are like a version where the person running the game can't leave, can only make 5 swaps, and you also win if he's sneaky and takes the ball away. Under these rules, you're much more likely to win because the game's operator can't do cheaty things. So why isn't C++ more like Rust and Go? Well, history. First, if people are very careful they can write code that's just as \"safe\" in C++. It just takes an awful lot of care. Second, when C++ was being developed, we didn't know as much about what isn't \"safe\". Computer Science is a pretty young field, roughly 60-80 years old by certain definitions. We had to make a lot of mistakes to learn what mistakes look like. Third, compilers are very complex and can take up a lot of computing power. The computers we have today are hundreds of thousands of times more powerful than they were when C++ compilers were developed. It may not have been possible to implement the features Rust and Go enforce *and* maintain feasible compilation times. We could update C++ compilers today, but it's usually hard and dangerous to dramatically change how such an old compiler works. There is a LOT of C++ code written that might stop working if the compiler suddenly required everything to be safe. That could be really bad, since that code probably does a lot of important things and the cost of reworking it to be \"safe\" could be immense. There are tools and compilers that do perform more rigorous checks, and I'm sure people use them. But if a C++ compiler suddenly *required* it, that would be a very unpopular change and people would refuse to use that compiler."
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mpu53q | How are NFT's bad for the environment | Technology | explainlikeimfive | {
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"text": [
"Such tokens are typically issued and traded on the Ethereum cryptocurrency's blockchain (taking up space in blocks where they are issued/transferred) The process of mining Ether consumes a lot of electricity, and a lot of electricity is generated using fossil fuels.",
"For scale, it consumes 26.5 terawatt-hours of power per year. As much as the entire country of Ireland. URL_0"
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|
mq5eat | . If the primary colors are RYB, why are all electronics RGB? | Technology | explainlikeimfive | {
"a_id": [
"gudvskq"
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"text": [
"Light and pigment are different. If you mix all the colors of crayons together you get black. If you mix all the colors of light together you get white. RGB is used in lights because red is the lowest frequency, blue is the highest and green is in the middle."
],
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17
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mq6cv3 | What’s keeping me from manually partitioning the hard drive on an M1 Mac, putting Windows on one of the partitions and booting from that? | Technology | explainlikeimfive | {
"a_id": [
"gue1vhe"
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"text": [
"ARM speaks a language that Windows doesn't understand. Microsoft has attempted to make Windows understand it, but it isn't quite there yet. Until Microsoft teaches Windows a different language, Windows cannot understand ARM. & #x200B; ELI15: Windows currently only offer full support for talking with a type of processors based on X86 architecture. For Windows, ARM based architectures is about as foreign, as a foreign language would be for you. While Microsoft has attempted to port Windows to ARM, the current results have been mediocre at best, and not the full Windows experience."
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mqaah7 | Can someone explain to me how scammers can use my number to call people multiple times, but I’m completely unaware of it? | Technology | explainlikeimfive | {
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"gueq855",
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"text": [
"It is easy to spoof caller ID. Spammers just rotate through a series of random phone numbers to prevent their calls from being blocked.",
"Most people rely on caller id, which is a very different system from what telephone companies use internally to route numbers. For example toll-free 800 numbers can get automatic number identification (ani) which is harder?! Impossible? To spoof. Caller id on the other hand is super simple to spoof, especially of if the caller is using VoIP. It's an audio tone that's sent between the first and second ring. If you're using a very old land line and your quickly pick up the phone, you can hear the caller id signal it's a very brief radio static like sound. The phone company doesn't verify it to be accurate. So you can claim to be whatever number you want. Kind of like you introducing yourself as George Washington, unless someone checks your ID card, they have to believe it as the truth."
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mqb29k | What makes flying a helicopter so hard compared to a plane? Is there a "computer-assisted" mode on modern helicopters that greatly reduces this difficulty? | A few sample questions, any info would be most appreciated: I've heard a bit about needing to constantly calibrate the two rotors (top and tail) to keep the copter from spinning out of control. Any more specific information on these difficulties would be useful -- e.g., what types of changes most frequently occur that lead to instability? Second, given that quadcopter drones exist, it would seem that these dynamic stability issues could be significantly ironed out by a continuous computer-driven calibration. Does that mean that most modern helicopters are now about as "easy" as a plane to fly, or no? Are such "auto-calibrate" features common on newer helicopters? Do pilots like to use them? | Technology | explainlikeimfive | {
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"Edit; Thanks everyone for not attacking this comment for it's simplicity as only the most basic of rototrcraft are operated as simply as this description any longer but understanding these basics will give you a basic understanding of most rotorcraft. It's not just coordinating the tail and the rotors as you describe that's required to control a rotorcraft. It's coordinating the three controls of the rotors, the *RPM's*, the *cyclic* and the *collective* in addition to controlling *Yaw* (flat horizontal rotation} with the pedals by controlling the tail rotor. The *cyclic* tilts the axis of the rotors left, right, forward and back like tilting an umbrella over your head. The *RPM's* keeps the motor in it's most safe and efficient operating speed range, while the *collective* controls the angle of the rotor blades as a group to increase or decrease lift. The tail rotor blows across the back end and by increasing or decreasing the pressure you apply here with your pedals you can counteract the natural tendancy of the helicopter to *Yaw* away in reaction to the torque produced by the main rotor or to control heading or yaw of the aircraft. The cyclic control is in the form af a larger joystick used to aim the lift forward, back, left or right in order to control orientation of the helicopter. If the overall rotor is tilted in One direction the helicopter will move in the direction that the rotor is tilted as long as the collective provides enough lift. The collective is in the form of a lever you pull up on which increases the angle of the blades of the rotor to increase overall lift. Edit; the collective also has a motorcycle grip style throttle incorporated into it that controls the RPMs of the motor independent from the collective control of the angle of the rotors. If you flattened out the rotors with the collective it wouldn't matter how much throttle you apply because the rotors would just be spinning flat and supplying no lift. In order fly you have to increase the RPM's of the rotor and then increase collective to increase the pitch of the rotors and provide lift and then control and direct that lift using the cyclic to tilt the rotors in the direction you want to go while preventing unwanted rotation (Yaw) using the pedals.",
"Flying in a straight line like a plane is easy, but that's not what helicopters are good for. Hovering, descending while hovering, and moving from side to side without turning are the three killer apps of helicopter. The only other way to do these operations is with a crane, and flying alongside a plane in a crane is not a thing you can do. It's flying AND doing all these other things that's hard. Computer assisted modes are fine for the easy thing, but the hard things are too hard for computers to do well, that's why you don't even see the US military (with virtually infinite money) building helicopter drones. (OK, the FireScout is a Helicopter, but it's only used from ships so that it can crash into the ocean.)",
"The basic problem is the dynamics (the physics that makes the vehicle \"go\"). With proper design choices, it's relatively easy to make an airplane with stable dynamics...it tends to (mostly) stay going in the direction it's pointed unless you do something to change it. As a result, a nicely trimmed airplane just needs slight nudges from time to time and otherwise just keeps flying. Airplanes that are designed to not do this, like high performance fighters, need computer control to remain stable. Helicopters have incredibly messy dynamics. You basically wad up all your normal airplane dynamics equations and thrown them in the trash and start over. Helicopters have a bunch of strange responses (due to basically being giant unstable flying gyroscopes) and you need to learn a whole bunch of muscle memory controls that aren't like anything else to make them do what you want. Unlike airplanes, where you can basically control pitch separately from yaw/roll (and even yaw/roll aren't that strongly coupled), a helicopter is coupled across all three axes. \"Coupled\" means that when you move in one axis, the vehicle responds in at least one other. Every time you change one direction in a helicopter it wants to change direction in two other axes if you don't actively compensate. Just as one example, to go up and down you increase or decrease pitch on the main rotor blades. This increases/decreases torque on the main rotor, which is what the tail rotor is trying to counter. So if you try to go up and don't adjust the tail rotor at the same time, the helicopter will start to spin (yaw). If you try to go down and don't adjust, it will spin the other way. So basically every time you touch the collective (the lever that controls main rotor pitch) you also have to adjust the pedals (which control tail rotor pitch). If you've never touched an airplane but have driven a car, I can stick you in a flight simulator and talk you through taxi/takeoff/flight/(bumpy) landing in about 20 minutes because the motions are intuitive and mostly separate, you just need to get used to how the airplane responds. The control motions for a helicopter aren't like anything else so there's no intuitive baseline to work from. Many modern helicopters have computer augmentation to ease pilot workload, especially in difficult situations like hovering. They are still not as easy to fly as a plane. Quadcopters and the like can't work at all without computer control. Modern human-sized quadcopters (and higher numbers of rotors) are \\*much\\* easier to fly from the human standpoint because they're 100% computer stabilized all the time. The human isn't really flying them, it's telling the computer where they want to go and the computer is figuring out what to do with the rotors. It's essentially full-time autopilot. Very few helicopters are currently built that way because nobody's figured out an efficient quadcopter package using turbine engines and we haven't worked up battery/electric motor technology to compete with turbines on range/endurance/efficiency. It'll get there eventually but high-power multi-rotors are inherently messy because big electric motors are still heavy (although much better), batteries are heavy, generators are heavy, and transmissions are heavy. So you either go with turbine engines are a stupid heavy transmission/shaft system to run the rotors, or go with four+ engines (really expensive), or some kind of turbogenerator with power cables and electric motors (also really heavy)."
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mqjwbo | What exactly happens to web content outside of the viewport when you scroll? Does the web browser still see it? What parts of the content does the browser ignore? | Technology | explainlikeimfive | {
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"Short answer - it depends. But more elaborate is that it depends on how the website was coded itself. By default, browser will load full webpage once you open the URL and that’s what happens in most cases. Some websites though uses approach that would limit this, for example lazy loading - which loads all the content, but images and first loads only the ones in viewport and proceeds load rest afterwards. This will result in webpage appearing to be loading quicker.",
"It's still there, stored in your computer's memory until you scroll back to it, otherwise there would be a noticeable delay every time you scrolled up and down a website. There's some cases where a webpage will only load content once you start scrolling, but once it's there, it's pretty much there until you navigate away from that page. The browser (and any plugins or other third party software you allow) can still \"see\" the full content, even if you can't. The browser doesn't ignore any of it, if it's on the page you're trying to view, the browser will try to load it. Pretty much any modern browser contains tools to inspect exactly what is being loaded when and how long it's taking, if you're particularly curious about how any website is loading its content. Edit: \"but once it's there, it's pretty much there until you navigate away from that page\" - realized I probably phrased this wrong. In the same way it's possible for a website to load content at-will, they can also remove content at-will, at which point the browser practically \"forgets\" about it. There's also the case where a website can instead just hide and show certain content, rather than explicitly adding or removing it, in which case the browser always sees it as there, but maybe it's just not visible to you. It ultimately just comes down to how the site is programmed and what (if anything) they're trying to optimize for."
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mqk83o | Night Vision Goggles | Technology | explainlikeimfive | {
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"As I recall, they use infrared light and digital imaging. Infrared is just outside of the visible spectrum and thus it doesn't light up the darkness as far as the naked eye is concerned, but it can register on digital cameras and be output by a screen as visible light.",
"It just has a camera lense that sees the tiny bit of light, way better than your eye, then a computer that enhances that light by however many light units, then the display presents you with that new enhanced image.",
"There’s a few different kinds. “Image intensifier tubes” are the ones we invented back in the 60’s and have a few layers: the first layer gets hit by light, and that later makes some free electrons out the back into a vacuum in the middle of the tube. In that middle section, they apply a voltage and speed up the electrons so that they slam into another layer, one coated with a material that glows brightly when the sped-up electrons hit it. So a little bit of light makes some electrons, which get turned into really fast electrons, which get turned into bright light. Some are just really, really sensitive cameras with a normal LCD display for you to look at. They all tend to utilize infrared light, just out of our visible range but what is actually pretty prevalent in nighttime illumination from stars and the moon. Thermal vision is entirely different. That uses light of a much, much longer wavelength and is based on how warm things are. Both thermal vision and night vision can help you see in the dark, but they give you very different pictures."
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mql6ts | How do nuclear reactors work? | Technology | explainlikeimfive | {
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"Uranium atoms are pretty fat, compared to other atoms. Think of a drop of water on a table. You can keep adding little drops to it, but at some point it gets too big and breaks apart. This is like uranium atoms. We can fire bits of atoms into them, and they burst. The thing is, this bursting produces a lot of energy. It also fires off more bits of atoms, that can hit nearby uranium atoms and make them burst. *These* atoms fire off other bits that break even more apart, and so we get a runaway chain reaction. In nuclear reactors, we use carbon graphite (pencil lead) rods to block some of these bits of atoms. This slows down the chain reaction, and stops it from running away. Meanwhile, we catch the energy that gets released with water. This heats the water up, boiling it, and turning it to steam. The steam goes through vents, which lets it turn turbines, generating electricity. Then, we use big towers to condense the steam back in to water to use again.",
"When uranium decays over time it produces heat,heat makes steam,steam makes the turbines spin,turbines produce power due to induction ,the chimneys cool the steam,water comes back cycle repeats."
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mqpfds | What makes internet faster or slower? | What makes internet speeds faster or slower? How do companies improve on internet speeds? | Technology | explainlikeimfive | {
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"It’s really just a function of plumbing, though digital. For example, the volume of cold water coming out of your bathroom faucet depends on the size of the spout on that faucet, the pipe from it through the house, the pipe from the house to the street and so on to the source. It also depends in whether or not other faucets in the same house are on, and to a similar extent faucets in other houses in your neighbourhood. If you want more water in the shower, you can buy a bigger faucet, but will require larger pipes through the house to increase the flow. Eventually, larger pipes in the house will exhaust the flow from the street and you will need those upgraded as well which requires the water company to invest. Internet is much the same. Each interface (faucet) has a size and if you increase the size at the edge (your house) eventually you will need upgrades in size all through the connections back to the source(s). Internet providers are constantly adding capacity and chasing slowness that comes from imbalances in edge capacity versus core and changes in usage patterns (popular content sources). Now consider all your neighbours install high volume sprinkler systems and have big pools that need filling in the spring and you get an idea of what IPTV and Netflix/Youtube etc have done to internet providers and how hard (expensive) it has become to ensure things are “flowing”. Just some rambling from your local digital plumber :)",
"Infrastructure, mostly. There are different types of cables which can carry data at different rates. Companies improve speeds by upgrading equipment and using more/better cable. What makes internet slow or not work at all is either nearing capacity for equipment (data is moving across cables/equipment as fast as it can and everyone is trying to use it at once) or physical damage issues (someone did some digging and broke a cable). There are lots of other nuances like traffic management and different places things can get bottlenecked but that's the gist of it.",
"For the end user, its almost entirely software settings on the ISPs equipment on the street, it sets the maximum bandwidth that the router on the street will let you use. The max bandwidth you can use is limited by the quality of the connection between you and the router on the street but its a pretty short run so a standard coax cable can support really high speeds over that short distance How much total speed that router can hand out to the people on your block depends on its connections back to the main office. If they provide more fiber optic cables or channels on the same fiber then it can send more data between itself and the main office so it has more bandwidth it can offer you. They can increase the channels by upgrading the sending and receiving devices to ones that can pump more data down a single fiber."
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mqpntq | How are more than a hundred million transistors Fitted on an area of about a millimetre Square? | Technology | explainlikeimfive | {
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"By making them *very* small. The \"Node size\" chip manufacturers talk about is based on a measurement of how 'big' the transistors are (the exact meaning of this measurement varies between manufacturers). Usually this is measured in nanometres, i.e. one billionth of a metre. -\"Hey! That would mean we need one metre to fit one billion\" you might think; but consider they're not on a line, but on an area. EIDT: To add, the manufacturing process involves shining light onto the material, and having the material brake down from the light. This is how you can make billions of nanometre-sized things cost-effectively. It's called \"photolithography\"",
"[This is a transistor]( URL_2 ) and the \"schematic\" of a transistor. So what you see is mostly the plastic outer cover and the big metal leads, but the actual \"transistor\" device inside can be extremely small. This is because a transistor is made by taking a wafer of pure silicon, and contaminating areas on it with atoms with extra electrons or fewer electrons (for example aluminium has 3 outer orbital electrons, phosphorus has 5, so they are +/-1 compared to silicon's 4 outer electrons). The process is called [doping]( URL_0 ), and the point is to create adjacent \"zones\" with \"extra electrons\" then \"fewer electrons\" then \"extra electrons\" again; this combination of 3 zones is what a transistor actually is. So because a teaspoon of material generally has [10^20 ]( URL_3 ) atoms in it, and you don't need that many to make a transistor, miniaturization is very much possible, down to a scale where the doped regions are so small that you can cram millions of them on a [wafer of pure silicon]( URL_1 ).",
"By carving them with light. You know how a tiny photo negative can be blown up into a giant photo? Well the reverse can be done with a relatively large image of a processor design and then using light and lenses to shrink the image onto a smaller space. If you shine this image onto a light sensitive material you can carve out the paths for transistors, pour the transistor material on top and then more or less sand off the excess. When done the material you want is only left in the areas where the light from your \"negative\" was projected, repeat this process with a different negative for each type of material you need and you can start to build a complex circuit at a very tiny scale. This takes an incredible amount of precision to pull off and due to the size difference in the machines vs what they are producing tiny improvements in the machining can have relatively large improvements in the efficiency of the processors they produce. However now we are making things so small that weird quantum mechanical effects are starting to cause issues so we won't be able to go much smaller without coming up with a whole new material to build processors on."
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mqr8vb | How do video games determine if a button is held or pressed without there being a noticeable input delay? | So, I've wondered for a long time how video games determine if a button is held or just pressed for 2 different actions in games without any noticeable delay. To me, even very slight delays are extremely obvious so I'm just not sure. Sorry if there is an extremely obvious answer, I've just always kind of wondered. | Technology | explainlikeimfive | {
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"From a programming standpoint, you essentially get a button down and button up command. So it's not constantly saying BUTTON PRESS when you hold down a button, the controller knows that the button is in a down state and sends the console/PC that button down command when you first press the button, then when the button is released it sends button up. From there, controllers tend to have input lags in the 3-30ms range, which is well beneath your normal human response time of ~80-100ms.",
"When it comes to milliseconds, most people don’t notice. There are people who will complain about any input lag but with modern technology and the speed in which the signals are transmitted to the system, there isn’t much of an issue. From there the system can kick off different threads to handle multiple inputs. If you’d like to see an example of noticeable input lag lookup google stadia.",
"Simply put, the computer is WAY faster than you. Let's go back to early days, slow computers, the old Atari, 1 MHz. Pressing a button sent an electronic signal over a wire to a controller chip, which caused a certain value in memory to be set. This happens in microseconds (millionths of a second). Your game is looping, and every several milliseconds (thousands of a second) it looks for joystick input by reading that memory location. This is far faster than you can react, so it seems instant to you. These days there are layers between that. Pressing a button causes a signal to be sent over a wireless connection, where it is is processed by the wireless controller and presented to the operating system, which in turn presents it to the game as an event. The game is then told to react a certain way whenever it receives a button press event. But with our faster computers, this is still much faster than you can react, so it still seems instant to you.",
"They sample input very rapidly...in most games this means sampling input every frame. So if you are running 60 FPS, that means sampling input 60 times per second - or every 16.67ms (roughly). That's much more quickly than average human reaction times. As for checking for a press vs a hold, that's going to depend on the specific design choices of a game. If, for example, you have a charged sword attack that you have to hold the button for 1 second to trigger, the game will read input for 60 frames (assuming stable frame rate) and if the button is held the whole time it'll trigger the charged attack. But, how do you keep animation smooth if the same button triggers an instant attack? You simply build your combat system with that in mind. When a user presses a button you *start* counting frames (time, technically) until it's released. If that button is released at any time before 1 second (for the charged attack), you *immediately* trigger the instant attack animation. The thing with button presses causing special actions, is they only cause the action after a certain amount of time. So if the button is released before then the game can immediately ignore the \"hold\" action and trigger the \"press\" action instead."
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mqrf9e | What is the difference between "high quality" audio files and "low quality" | What is the difference between "high quality" audio files and "low quality" what are you supposed to be hearing in these higher quality tracks that isn't in the lower quality ones? for example i tried this test URL_0 and it might as well have been the same file 3 times. there is no difference between all the files to me. | Technology | explainlikeimfive | {
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"Compression. Mp3 compresses the sound file which is lower quality. If the sound itself has peaks of 100 for example, to truly experience the sound as if you were there, it would need to be saved exactly as it was played. If you record it as an mp3, it will compress it, and those peaks will shrink down, let’s say to 50. So every part of that recording will be compressed down, so that that 100 which is now 50 will sound normal. This sacrifices quality, but it also makes the file size way smaller. But really unless you work professionally in sound and have expensive equipment you’re probably not going to notice much difference",
"So from a recording perspective, there's a thing called bit depth and sample rate. These are two of the major factors in determining the quality of an audio file. Bit depth is the number of 'bits', which are binary numbers, you have in order to describe something.. which in this case is the sound file you are recording. You can think of bit depth like the resulting accuracy of the sound wave due to the hardwares efficiency at recording, higher bit depth recording enable there to be less noise due to the availability of what's called a noise floor. Noise floor is what's typically referred to as the self noise from the actual recording equipment, so a higher bit depth enables you to basically push the noise down further to inaudible levels and therefore have a cleaner signal. Sample Rate you can think of as how many samples are being recorded a second in quick succession. You can think of this as how older animation graphics painted each frame and played them in quick succession in order to get a detailed moving animation. The same thing for audio, sample rate is how many cuts of the audio we have In order to give a more details picture of the audio. When playing back recordings we maybe compress higher bit depth and sample rates down to a more manageable/ sizeable format. You can find CD quality or better streaming platforms can output audio at 16bit and 44.1khz (sample rate). This is a typical output format you see in most situations as most playback systems will only output this amount of detail. Mastering engineers will typically master tracks and tailor output formats dependent on the playback systems that the song might be played on.",
"What device did you use to listen to them? If you're headphones/speakers aren't good enough, there might not be any difference. It's the same as with screens. 200 fps means nothing, if you're screen is only able to produce 60."
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mqslp8 | How are digital photos made? | Specifically in cameras with mirrors (DSLR) a photo transferred to what you suddenly see on screen? And is the technology same for all kinds of photography: phone, different cameras, etc.? Thanks | Technology | explainlikeimfive | {
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"Digital cameras use image sensors to take the picture. These sensors are grids of light sensitive components that generate an electrical signal based on the intensity of the light they receive. The components are sensitive to different colors (similar to the pixel layout on a tv screen). When the camera takes a picture it reads the current \"state\" of each one of those sensors. All digital cameras work on this same basic principle. A DSLR is similar to a SLR in that a mirror redirects the image through the lens up to the view finder. When the camera takes the image it moves the mirror out of the way so the image falls onto the sensor instead. In a film SLR the mirror is moved so that the image falls onto the shutter, which then opens and closes to expose the film."
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mqt0f8 | why aren't more portable devices waterproof by now? It seemed like the direction things were going a few years ago. | Technology | explainlikeimfive | {
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"Extra cost combined with not much need. Its a handy feature to have when you need it, but for the most part people aren't trying to use their devices in the rain/water. Waterproofing all of the seams and openings takes extra time and effort which makes manufacturing more expensive and complicated."
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mquj3n | Why do some phones have 108 megapixel cameras, while others stick to 12? | Is there no set in stone way to imprpve picture quality? | Technology | explainlikeimfive | {
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"The pixel count of a camera doesn't directly imply superior image quality. The biggest reason is that if there are more pixels in an imaging sensor, the less light reaches to each individual pixel. Dimmer light means poorer image quality. To compensate dimmer light per each pixel, you either need better (more sensitive) imaging sensor (which is very difficult) or just bigger sensor (which is not quite suitable for compact devices like cell phone). For example, old DSLR's (which have much less pixel count than modern phone cameras) have much much better image quality despite far lesser pixel count because the sensors in them are about 30 times larger. Though imo Samsung Galaxies (108 MP) catch much more detail than Apple iPhones (12 MP). Apple might think that such high detail is not absolutely necessary for the consumers. Instead Apple does a lot software tricks to fake images look better."
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mqvi8v | How does making a figure 8 with your phone improves it's sense of direction? | Technology | explainlikeimfive | {
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"The compass in your phone responds to the earth's magnetic field, but the compass wants to experience the magnetic field changing around it, so it can know which way is which more effectively."
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mr4kin | Why does a car engine make the vroom noise, what is actually happening inside to make that happen? | Technology | explainlikeimfive | {
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"Car engines contain cylinders, cylinders use explosions to bounce up and down, turning things which then eventually turn the wheels. The vroom vroom noise is the sound of the explosions and resulting movement in the engine.",
"Little tiny explosions. An engine works by taking in gasoline (or other fuels), mixing it with enough air to burn, compressing the mixture, then igniting it. The explosion pushes the piston down which in turn spins the crankshaft. The spent fuel then leaves the engine through the exhaust, along with the sound.",
"For your usual gasoline engine, there are a bunch of explosions every second, all timed one after another so that it gives a mostly uniform power to the car’s drivetrain. The sound is the combination of the explosion inside the engine and the exhaust gasses from those explosions rushing through and out of the exhaust pipes."
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mr5qom | How does a smartwatch get heart rate using "green light" underneath the watch. | Is it also accurate? How does result compare to an actual blood pressure machine? | Technology | explainlikeimfive | {
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"That green light illuminates the skin, measuring changes in blood volume in the capillary vessels. They don’t really measure blood pressure, they measure pulse, and some level of VO2 (volume of oxygen moved through your system when exercising). The pulse I’ve always found to be accurate, and the VO2 max is also relatively close. Other metrics I’m not sure on yet. But the green light isn’t much different than the finger clip pulse-ox light that is routinely used in medical care",
"Your blood absorbs the green light, so it monitors how much light reflects back and can detect each pulse of blood as dips in the amount of green light reflecting back."
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mr5s62 | What is the endgame for the rocket boosters that can land again on Earth? | I’ve seen the videos and it’s Absolutely incredible. Where does this tech take us, what is the endgame, and what kind of advancements can be made to it to progress? | Technology | explainlikeimfive | {
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"It makes space launches less expensive, which in the long run makes space more accessible and enables other activities because the economic barrier to reach space is reduced.",
"The endgame for reusable boosters is speed and cost. If you reuse a booster, you don't have to: * spend time crafting a new one, or * spend money crafting a new one. That's basically it. It means you can fly missions more rapidly, and use materials on other things.",
"Reusable rocket boosters can reduce the cost of launching payloads into space pretty drastically, since the boosters aren't exactly cheap to product. The challenge has been recovering them in good enough condition to reuse, which SpaceX seems pretty confident after working on it for a while ([and quite a few failures]( URL_0 )) One benefit of less expensive launches has already started deployments: low orbit satellite internet (Starlink)",
"Let's say you run an airline. One airplane costs $200 million, and carries 200 passengers. If you ditch the airplane in the ocean and build a new one at the end of each flight, you have to charge a ticket price of $1 million per passenger to pay to replace the airplane. Of course that's a terribly inefficient, downright silly way to run an airline, and no real airline actually does this. Instead, you build your airplane so that it can be re-used; it might make 10,000 flights over multiple decades. You still have to charge $1 million per seat over the lifetime of the plane, but that $1 million can be divided among the 10,000 different passengers who sit in that seat on each of the plane's 10,000 flights. This means you only have to add $100 to the price of each ticket to be on schedule to save up enough money to replace the plane at the end of its life. Making space rockets re-usable will eventually reduce the cost of getting to space by *a lot*, since you can spread out the cost of the vehicle over many trips."
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mr6wsh | Why does a crystal radios radios antenna have to be so much longer than a normal radio | Technology | explainlikeimfive | {
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"The antenna acts as the power source of the radio and needs to be long to harvest as much energy as possible from the very low energy radio wave. Powered radios simply amplify this weak radio wave."
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mr8fkr | Why do video game developers choose to only release games only on some consoles/PC but not others? How much more work does it take to program a game to operate on a different console, say Switch vs Playstation for example? | Technology | explainlikeimfive | {
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"It takes a lot of work. Consoles tend to have less power than PCs and each of the major consoles uses a different operating system. PC and Xbox share a lot of internal code, but PCs have thousands of combinations of parts, compared to the consoles all using the same processors. For a small studio this is a lot of work. In general game companies have two options: make a game run okay on all platforms or really well on one. I’m a PC gamer, but I’m shocked at how well God of War and Horizon Zero Dawn run on the PS4. Knowing exactly what hardware your game will run on is a major help to optimization. And also, game companies sometime sign contractors to only release on a single console. Sony may pay a company a million to not sell their game on the Xbox. Or in the case of Bethesda: Microsoft owns them, so they’ll be making almost exclusively PC and Xbox games from now on. There you go, it takes a lot of people and time to make a good cross platform game, and there’s a lot of money involved in keeping games from getting ported.",
"developing for consoles have a lot of limitations, require you pay licensing fees, console manufacturers require that they to verify your updates before you can push them out (thats why you cant mod skyrim and stuff like on pc), you have to worry about supporting different control schemes, you need separate servers for consoles and pc unless your game works well in crossplay, you will have more bugs come up when you support more systems, it's sometimes easier to integrate with something like the steam API rather than integrating separately with each platform, you need to hire experts for the different consoles you support, and there's probably a whole host of other reasons people will bring up",
"A good comparison is trying to take a European Car and importing it to the U.S. I mean, cars are cars, right? Shouldn't be too hard. However, while European Cars and American cars are basically the same technology... There are a bazillion American rules and regulations that don't match European rules and regulations. There are obvious things like which side the driver sits on. There are less obvious things like bumper heights or fuel standards. Then there are really dumb things like European Cars having wider license plates than American license plates and thus the screw holes are in the wrong place. Each of these differences requires attention from the car importer and it takes a lot of time and money. Porting a game from one platform to another is similar to importing a foreign car. It seems easy since all game consoles basically run on the same basic technology nowadays, but it's the small things that take a lot of time to get just right.",
"it's not just that - different platforms have different costs involved, and different expectations. some smaller companies can't justify the cost to get it certified for consoles, so they just don't bother.",
"Different hardware, different APIs, often different capabilities--you can produce a game that has much better effects on a PS5 than you can a Switch because it's simply a far more powerful machine; the Switch sacrifices capability for portability. If you were to just do a straight port of a Switch game to the PS5 with no upgrades then PS5 owners would consider it to be rather shabby looking. So, in the most extreme examples you could be talking essentially rewriting the game from scratch, including all the visual assets--your only advantage is that you already know how the game is supposed to work, and you'd probably be able to re-use the audio assets because those capabilities don't change much between systems."
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mr9coz | what is the difference between electric and electronic? | Technology | explainlikeimfive | {
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"electronic is when you transmit digital information/signals electric is when you use electricity to power your device.",
"To be a little more specific, electronics implies the device uses transistors, which are components that allow for things like logic circuits and amplification.",
"Simplistically: Electric is usually the term used for something mechanical driven by electricity, like a washing machine, while electronic is used for things that use electricity as power source to do calculations of some sort, like a computer. Instead of driving a motor, the electricity (in tiny amounts) is used to turn \"switches\" on and off in processors etc. In a washing machine, the program cycles are electronic, while the engine is electric (electro engine).",
"Electronic generally implies that there is some kind of integrated circuit/microprocessor logic in the device which plays an important part in its functioning, whereas “electric” (as opposed to electronic) devices use primarily “simple” components like motors, heating elements, lights, and non-semiconductor based circuitry. But there is definitely a lot of fuzzy overlap with these terms."
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mr9otp | So what would happen if a hospital got hit by a power outage? | Technology | explainlikeimfive | {
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"Hospitals generally always have backup generators that kick in immediately in the event of an outage, as long as they have fuel for them, power outages are not an issue.",
"Hospitals are built with a backup system in place, to protect in case of a power outage. This is usually a generator that will kick in to protect the patients as necessary, until power can be restored.",
"Depends on the location but in Australia typically they have UPS (uninterrupted power supply) battery backup for the main computers, surgical lighting, 30% of the hospital lighting and comms systems. The computer systems are designed for 15-30mins backup and the lighting is 90mins. This system provides power the instant mains power is lost untill the generator is up and running. The hospital will typically have a diesel generator with diesel storage for 24hrs at full capacity. The systems that have generator backup will vary depending on the hospital but typically it's any system that is critical for patient safety such as the medical gases, isolation rooms, life support etc. The generator is required to start within 5mins - newer systems can usually ramp up in 30secs. A 'disaster' hospital, designed to be able to withstand a natural disaster, will have full backup of the hospital with duty/standby (2N) redundancy on the generators."
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mr9skf | What makes the storage of data so costly? | Both analog and cloud thoughts are welcome ~ all thoughts really (that aren't humanely offensive) ! Music producer. Constantly re/de-connecting external HDD's for the sake of 'online files' in one project. Is there also a proportion between data-size and what vessel encompasses that storage? | Technology | explainlikeimfive | {
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"First I'd like to say that storage of data in the cloud is dirt cheap, so I don't really understand the motivation of your question. A rule of thumb is $0.02 per month per GB. How is that expensive? Now for the cost drivers: * Availability: If you want a guarantee that your data will always be available to you, the provider has to duplicate it, so that if anything bad happens to the \"original\" storage they can point you to the \"copy\" instead; Similarily backup & recovery also require additional copies to be kept all the time, so for every GB of data you actually have to pay for several more GB as well * Security: If you want your data to be safe from theft and manipulation, the provider has to employ security measures, like different types of encryption, an elaborate idendity and access management, network separation etc.; this is not specifically for your data, but you will have to pay for a share of it * Processing: The actual expensive part of cloud hosting is not data storage, but data processing. So the more you work with that stored data, the more expensive it gets. Copy stuff? Expensive. Encrypt/decrypt stuff? Expensive. Upload new data? Expensive. Browse your files? Expensive. * Hardware and basic operations: Your data resides on some kind of hardware, even in the huge cloud datacenters of Amazon, Microsoft, IBM, or Google. That hardware costs money, both in original purchase and in upkeep, as in replacing faulty disks, providing it with electricity, cooling it, monitoring its health, occasionally scanning for viruses etc. * Profit: The hosters want to make money of the services they are offering to you, so most likely you not only pay the storage, but also quite a few \"useful services\" around it. This is like when you buy a washing machine, they also offer you a warranty extension, water softener, sock sacks, special detergents etc.",
"storage of digital data has become cheaper basically by the day over the past few decades and honestly is far from costly right now, at least if you're not talking \"longterm-storage\" aka 50+ years storage, that requires a bit more thought and relies on systems that arent directly related to the consumer products. I have no idea, what you mean by \"constantly re-connecting external HDDs for the sake of online files\", normally you should just connect it once and then it stays connected. you could also consider getting a NAS if you want to access that data from more than one computer (which I am interpreting is what you mean by 'online files') wenn you're talking about analog data then obviously there's a connection between data-size and the required size of the vessel, like your room needs to have a certain size to fit a specific number of books or vinyls into it. for digital storage, well there are limits to the storage capacity of modern hard drives, but since those hard drives are basically all the same size with varying amount of storage space (from basically nothing up to 10 or so TB per disk) and the fact that you can often compress digital data (zip files, for example) I'd say there's no direct connection there."
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mraz5o | How does wireless connection bandwidth work, why does the speed differ so much from factors like connection quality compared to wired connections where it's pretty much a set speed? | When you use a wired connection the stability of the connection always stays the same, meaning the device knows when and how it will receive a signal. However, a, for example, WI-FI connection is very unstable compared to a wired, and the connection speed always differs during a period of time. I've always wondered, how does the receiving device know at what speed to expect to receive the incoming signal, and not lose chunks of data when the speed suddenly drops/rises? | Technology | explainlikeimfive | {
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"The speed is always the same (agreed upon before the transmission starts), but packets might have to be resend when something interferes with the transmission. That can be anything from a random other electrical device turning on to something conductive moving through the room. Or even just being too far away and other signals being \"louder\" than yours. Each packet is checked for correctness with a \"parity bit\" wich basically just says \"the last packet should be even/odd\" (or dividable by any number for better correction) so every packet read wrongly you simply repeat it wich slows the speed since more data is sent. You don't have those issues with cables simply because you can shield them (I.E. put a fine metal webbing between layers of insulation). That prevents outside signal from disrupting your transmission.",
"This is taking me back a few years, used to have to explain this sort of thing to customer all the time. The 2.4 ghz range that WiFi uses is used by a large number of other devices so they can interfere with your WiFi connection, the construction of your house can interfere with it, so many things can impact WiFi. If your device is capable of using 5ghz and your router is compatible, try swapping to that. It has a faster top speed, albeit a lower range, but there are way fewer devices also using it, so it will be impacted less by other devices causing interference. As an example, please of devices in the 2.4 ghz range: cordless phone handsets, baby monitors and the like. As /u/luckbot advised, the sending and receiving devices act as if they are at max speed, but it is the external factors that impact it. One thing worth considering is setting up WiFi extenders around the house if you are noticing a problem in a particular part of the house. I had one customer, many years ago, could not get WiFi in one side of the house. Turns out it was 2 old farm cottages that had been knocked through into one house and the old dividing wall between the 2 was full of big metal pins which was effectively acting as a Faraday cage. Set up a rouen on the other side of the wall as a WiFi access point and connected it with power line adaptors and got full coverage."
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mrb4ks | How does my computer know I removed the CPU and put it back in when it was turned off the whole time? | Technology | explainlikeimfive | {
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"I think it’s due to the coin battery in there to keep certain files and programs on the motherboard from getting erased when there is no power to the computer"
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mrbudy | Why do datamining leaks happen? | Technology | explainlikeimfive | {
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"> Why do datamining leaks happen? For the same reasons all security breaches happen - because people have a grudge against their employer, don't shred their documents properly, greedily click that link for the 10000€ bank transfer from Nigeria or think password managers are for chumps."
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mre1jn | Can we create our own internet ? | Can we create a connection to the internet ourselves without having to use a cellular 3g/4g subscription / wifi subscription? | Technology | explainlikeimfive | {
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"The internet isn't a resource like wood or water that can be \"produced\". It's a connection to the rest of the computers/servers/sites on the network. It's a bit like, \"can we create our own, separate road network?\" Yes, you certainly can, but you'd need to build your own connections to each place that you go to. You'd need to ask your supermarket if they would let you build a separate road connection to their property, with a separate parking lot, just for your users. Same for the drug store, Amazon warehouse, and any other company/location you'd be interacting with. You'd need to get approval from the town/city/national governments to build your road system in parallel with (but not interacting with) their roads. It's not impossible to do it. But that's about the best argument that can be made: it's not physically impossible.",
"If you're willing to go through the process for gaining government approval to create your own infrastructure for data communications between customers and get enough people to use your network to make it worthwhile, i guess. That's a very steep mountain to climb",
"ISPs don't make the internet they connect you to it. If you want to have access to the internet you have to connect to it somehow. The easiest way is through a provider, because that is what they do, but you can connect to any computer connected to the internet and get your access to it routed through that computer. The ISP themselves connect to each other through a process called peering and they will do the same for you if you have enough computers that connect through you to the rest of the world. You can also use the protocols that the Internet works on and build your won separate network. Any two computer connected to each other via the Internet Protocol (IP) are in theory *an* internet, not just the Internet that everyone else uses.",
"URL_0 /r/darknetplan Folks have been working on a separate network for a while. What it really needs is users and content.",
"Yes. You can pay for a link, through the phone company, of install your own dark fibre, paying the city and utility costs, connecting your house to the nearest peering point. Then you can buy a cvrrier class router ($150K) to install at the peering point. You may need to pay peers for traffic, unless you connect a sizeable number of users. This is what ISPs and community broadband companies do.",
"The Internet is largely built on trust. No one really likes to admit it, but its true. Trust that no-one will fuck things up. And that makes people twitchy. Do the people you want to connect to trust that you are who you say you are? If so, in theory it boils down to a wire connected to a comms cabinet, connected to an exchange, connected to a data centre connected to everywhere else in the world. HOWEVER in the real world, almost everything is hosted by a depressingly small number of organisations. AWS hosts nearly half the WWW. Google took over Usenet many years ago. If you can't get to them, you can't do jack. And if they say \"no\" you're fucked. Setting up your own connection is possible, but unbelievably expensive, will require massive negotiations with major corporations and frankly really not worth it. Back in the 70's and 80's maybe. Not now.",
"There are several different questions you could be asking. I'll try to answer all of them. - *Can I connect to the Internet without paying somebody a monthly fee?* No. - *Can I connect to the Internet without using a radio?* Yes, but you'll still have to pay an ISP every month. If you don't want to use a 3g / 4g / 5g cellular connection, you can get Internet from a cable or DSL provider in most places. You still have to pay for this subscription. If you don't want to use Wifi, you can connect your device to your router with an [Ethernet cable]( URL_0 ) instead. Most desktop PC's and many laptops have built-in Ethernet connectors. You'll need an Ethernet adapter for your phone, tablet, etc. - *Can my friends and I create our own network?* Yes. You don't have to pay anyone a monthly subscription to connect computers together. (You still have to pay for parts and electricity, of course.) You can connect multiple computers together using Ethernet cables to connect them to a switch or router. You may need to make some simple changes to the OS or router's networking settings. You can even get rid of the cables if you use a Wifi router. The catch is that the computers have to be physically connected with Ethernet cables, or within a few dozen feet of a Wifi router. So for example, if you wanted to visit your friend's website, you'd need to have your friend physically bring a computer over to your house. Your friend would need to run their webserver software on that computer. You could visit the website running on the computer in your house. There's a lot of different server software these days. So you can create a network with websites, chat, downloads, and so on. All running on computers in your house. There would be no possibility of connecting to Reddit, Google, Facebook, and so on. Because those websites are running on computers you're not connected to, outside your house. If you wanted to connect your network to computers in different houses, you'd have to physically connect a wire between the houses. This might be feasible to do with your next-door neighbor if you're willing to spend a couple days digging a ditch, putting the cable in it, and figuring out how to safely drill a hole in the wall to get the cable inside each house. If you're talking about multiple friends in different locations, you'd have to get a bunch of government permits and pay millions of dollars to run a miles-long cable through a bunch of different properties you don't own.",
"You could setup a network of packet radio modems/computers via shortwave radio. Or You could setup a mesh network of XBee Pros connected to computers that have up to a two mile range each outdoors.",
"Yes. In fact most businesses do this and call it an intranet. Some hobbiests do it over radio waves with HAM radio or WiFi. & #x200B; All you need is a way for the computers to connect to each other. You just setup a little infrastructure and you have your own internet. Now the downside is that it can't access the rest of the internet so the only websites/etc available are those you're hosting on your private internet.",
"If you are asking about having a connection to the internet that does not require some sort of service that is already in place, then no, all connections to the internet that exists have to be done through some sort of existing connection. This connection allows access to the network of computers that the internet exists on. You do not necessarily need a \"subscription\" as there have been ways to \"hijack\" an existing connection, but again this is using an already in place connection."
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mrev4o | How does refrigeration work? And are their limitations in size both small and big? | Technology | explainlikeimfive | {
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"Basically, you have an easily liquefiable gas at the back of the fridge, typically some sort of halogenated carbon based molecule like a Freon (includes the greenhouse gas families CFCs and HFCs). Gases can change temperature fairly easily with pressure, and will decrease temperature as they expand, that’s why deodorant feels cold when you spray it. The refrigerant gas comes into contact with the inside of the fridge in a sealed system after passing through an expansion device, where it will then absorb energy from inside the fridge, cooling it down. It is then moved to the zigzag of pipes on the back of the fridge using a compressor, where it then heats up to a higher temperature since the pressure increases. The heat is bled off into the atmosphere, then the gas is depressurised again into the fridge, completing the cycle. There aren’t really any limitations per se, hence why you can have small drinks fridges, but it’s a lot more efficient at larger scales since you’re using less energy per volume of air to keep it cool because of the cube square law - volume increases faster than surface area. Surface area is a major factor in transferring heat, since it’s the boundary where heat can leave a system."
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mrf3ms | In computers, why do some files, even if they are the same size, take longer to be moved or deleted than others? | I noticed this when I deleted a 2 GB video file on my laptop today, which took less than 5 seconds. But when I deleted a separate folder that was smaller than 2 GB, it took way longer to get deleted. | Technology | explainlikeimfive | {
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"This has to do with the way computer usually handle such things as deleting or moving files. Normally when you delete a file, the computer does not actually delete the data itself. Instead it goes to a sort of index where it has a tabel that says where each part of a file is located on the storage device. You can think of it as going to the table of contents in a book and striking out the entry for a chapter and what page it is one. If you flip though the book you will still find the chapter, but if you only look at the table of contents it is gone. From that metaphor you can also see why striking out a single chapter that goes fro a hundred pages is faster than striking out 100 chapters that are only a page long each. Something similar happens if you rename or move a file around in the same drive. The file itself stays put you only mess with the entry in the table that says where what is. You can move a file that is hundred of gigabytes from one folder to another in almost no time, but moving a hundred tiny files takes a bit of more time.",
"The video file is one single file. So even though it's \"bigger\" at 2 GB, it's just one thing that the computer needs to pick up and drop in the recycle bin. The folder has *many* files. Even if the folder itself is smaller than 2 GB, the computer has to figure out how many files are in there, how big they are, then basically pick up and drop off each one individually to the recycling bin. Sort of like if you're moving into a new place and you've got one bed, and then you've got ten boxes that don't have too much stuff in them but they take up the same amount of space as the bed. You'll probably get that bed into the house in one trip, but it's going to take you multiple trips to take all those boxes in."
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mrgpla | why do computers sometimes make horrible buzzing sounds when crashing/locking up? | Just had this happen to me for the first time in a while and it always catches me off guard. To give my example, I was listening to music on my PC, and mid-song the PC completely locked up and a loud buzzing sound came through my headphones. I've had it happen in the past with other PCs and with game consoles as well, but why does it happen? | Technology | explainlikeimfive | {
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"The sound hardware in a PC is designed to work with as little interference from the CPU as possible. To that end, it's generally set up so it can play a chunk of audio from memory without interference--all the CPU needs to do is update the location the audio hardware is playing from every now and again. If the system has completely locked up and is no longer responding, the audio hardware will often just keep playing the last little bit of sound it was told to over and over again--depending how long that sound fragment was you might get an obviously repeated bit of music, or just a buzzing."
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mrgwj3 | How did old NES cartridge games save your game? | I mean the ones like The Legend of Zelda that saved your game without the use of passwords. How was your game saved on the cartridge? Did it work the same way as an old floppy disk? | Technology | explainlikeimfive | {
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"It saved on a small memory chip inside the cartridge. They had a small battery (much like, probably even identical to, the ones you find on computer motherboards). After a long enough period of time those batteries do die and you do lose saved progress and the ability to save until you replace the battery (particularly anything you save is lost as soon as you remove power).",
"They would typically have battery backed ram. Flash memory wasn't a thing yet, but RAM was. Specifically SRAM which stores data as different transistors being activated/deactivated. It looses data without power so there would be a coin cell on the board to keep your saves.",
"The cartridge has a RAM chip dedicated just for saving your game progress, and a little watch battery just to keep that RAM powered when the NES is turned off / the game is removed from the console. I forget which exact chip is the game-save RAM, but you can see the battery in this picture of a crystal-clear NES cartridge. It's the silver circle on the top left of the circuit board: /r/gaming/comments/5slkhc/ Fun fact: On the original NES consoles, you were warned to always hold the Reset button when turning off the console with a game that had save data. The original NES's Ricoh CPU didn't have any internal circuitry to make sure it powered off relatively gracefully, so random data could get written to random addresses when it powered off... including the game save RAM. Holding the Reset button would hold the CPU in a Reset state preventing this from happening.",
"Games that had non-password save options had a battery inside which allowed the cartridge to store the save data when the console is powered off. See a picture here: URL_0 This holds true for other cartridge-based systems like the SNES/N64, Sega Genesis, etc.",
"Cartridges in general were basically add-on computer parts, so they would come with RAM and disk memory and sometimes added processing power. The differences between graphics for example on the SNES level between launch games and games at the end wasn't just upgrades in development, the hardware in the cartridge was significantly upgraded as well.",
"> Did it work the same way as an old floppy disk? Actually, yes, just probably not the version you played. The first Zelda was released initially for the Japanese exclusive [Famicom Disk System]( URL_0 ), a floppy-based addon to the Famicom that allowed bigger games, cheaper production, and yes, saveable games. Previously gamers had to rely on passwords or a even a [clunky cassette tape addon]( URL_2 ) to save their games. You could even take a special disk to [kiosks]( URL_3 ) at some stores and download new games and extra content to it. 80s DLC! Gaming Historian has a [great overview of it]( URL_1 ). It never released abroad and cartridge tech improving with battery saves and greater capacity meant games like Zelda could be released to the foreign market on cartridge."
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mrjba3 | Why are PS4 and PS5 unable to read PS1 or PS2 discs? | They are clearly able to emulate the games based on the PS1 and PS2 games being available on the digital storefront. Edit: Thank you all for the informative replies. | Technology | explainlikeimfive | {
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"> Why are PS4 and PS5 unable to read PS1 or PS2 discs? For the same reason a VHS player isn't able to read an SD card. It's not built for that kind of application. The PS4's and PS5's drives are physically unable to read CDs, only Bluerays and DVDs.",
"PS1 and some PS2 disks are based on the CD standard. The drive in a PS4 (and I assume PS5) doesn't read CDs. Among other things it's only equipped with lasers for DVD (650nm) and Blu-ray (450nm).",
"Main reason: Different CPU architectures. Example: Moving to a completely different country and trying to read the news paper in their language with no prior lingual experience of that country. Imagine the code of the PS1 games being one language and the code of the PS5 games being another language.",
"Several reasons. But the main ones are quite simple. Fully emulating a console so it works with all discs would be difficult. Games they control can be modified to work (assuming they use emulation in the first place - they might be ports) They don't make any money from you if you use existing games.",
"CD, DVD and BluRay all use different lasers with different wavelengths. A lot of commercial players like the ones you get for computers or media players does come with multiple lasers that can read all disk formats. However PlayStation have chosen to save some cost by only including one laser. There are also some other differences in the tracking mechanism which makes them incompatible. They used the tracking of the grove in the CD to prevent illegal copying of the disks but this made the hardware a bit more complicated which they did not add to the later DVD and BluRay players in the later versions.",
"tldr; it's not worth the cost and headache to develop and support the functionality. To break it down further: 1. As disc technologies developed data was packed smaller and tighter to fit more onto the discs. Each one requires different lasers with different resolutions built into the drives to read the data. 2. As consoles developed the code or language behind them changed. To read and understand the code from an earlier model requires translation (the emulator). It's an oversimplification but you could compare it to if you only speak English and you want to talk to someone who only speaks Spanish you would need a translator of some kind in the middle to listen to one language, convert it to the other language, and back and forth. You need to find or build that translator (time and money), using it will consume resources (processing power, memory, heat), and it's very easy for an 'incomplete' translation to occur (bugs, bugs, bugs). 3. Support and development costs now go up with each increase in complexity of the above two. There are more people you need to pay, more hardware you have to buy, you have more possible points of failure, more software to debug and a pile of ancient games you're now stuck supporting long past their end of life, all for a dubious 'value' that realistically the vast majority of your consumers are going to ignore, or treat it as a curiosity. And you end up having to deal with somebody's mother on a Twitter tirade who finds a copy of Atlantis from the PS at a garage sale and wants it to work on their new PS5 so their toddler can play a game. 4. Margins are already slim on consoles, sometimes sold at a loss so the company can get them into as many peoples hands as possible on a bet they'll make up for that on the games. They need to show a profit or they go under. The money earned from the sale of those old games went bye-bye long ago, either in profits or development of new systems and new games. The added cost and risk don't make sense for the limited value the functionality is going to offer. It makes more sense to redevelop or remaster the popular games and sell them for a nominal fee for the people that are serious to about wanting to play it. They get a little money back to support the development and they can tighten their support focus considerably which makes for a much stronger product and a better experience for the consumer (ie. you and me).",
"They do this on purpose because they have something on the system called Playstation Now, which requires you to sign up for a monthly subscription in order to use it. It’s about making money, plain and simple.",
"They can, Sony just doesn't let you via software lock. They want you to pay for Playstation now"
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mrl3xz | Why will streaming services still suggest videos on their app that I have rejected 1000 times? | Technology | explainlikeimfive | {
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"As always, such algorithms are responding mainly to what has worked for them in the past, at least moreso than to top-down programming by their creators/owners. So, apparently on the 1001st time, other people have clicked.",
"It probably reevaluates the shows you have watched regularly and regenerates the list of shows you are likely to watch based on you previous views. There is no particular incentive not too show you something you rejected in the past, maybe another show will have changed your interest in the rejected show."
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mrn8ej | Why do some screens on electronics capitalize all the letters except for the first one? | Like, a little screen that says “rEADY” on an oven. It happens a lot on alarm clock screens, or that kind of thing. I saw it in Better Call Saul when he’s taking Cinnabon’s out of the oven and I realized I’ve seen it a lot before. I have a picture but it’s not allowed to post here. | Technology | explainlikeimfive | {
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"It's not that they're capitalizing the first letter in particular... it's just that they're very limited insofar as how they can shape letters. They're really only meant for numbers. If you look closely at that type of display, it's made up of a bunch of lights in the shape of bars in very specific conditions, and a bar can only be turned on or off: - | | - | | _ So the only way they can form the letter R is in lowercase. If they tried to make the closest shape to an uppercase R it would just be an A. This type of display is called a [\"seven segment\" display]( URL_0 ), because it's made up of seven bars. For something that can do letters better, they would be better off using a fourteen- or [sixteen-segment display]( URL_1 ). Those have more lines, including diagonal ones, to allow them to shape letters much better."
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mrrqzb | Why are there ads on Cocomelon's YouTube channel? | Technology | explainlikeimfive | {
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"You are allowed to show ads to kids, but they have to be kid friendly. I think YouTube got in trouble because they were showing targeted ads to kids and perhaps ads of a less than child friendly nature. YouTube is allowed to show non-target and child approved ads to children. If you think about, TV does this as well. When you watch a kid's channel, or child programming, they show commercials. However, the commercials are child friendly (usually they are toy commercials). You won't see too many liquor commercials or trailers for violent movies in the ads of a kid's show."
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mrrz4x | How did gameboys not only function in but actually need very bright external light in order to see the screen, but modern screens with built-in backlights are nearly impossible to use on bright sunny days? | Technology | explainlikeimfive | {
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"Different technologies. The game it used reflected ambient light and filtered it through the crystal matrix; modern displays have a projected light from behind that gets filtered as it comes out towards your eyes. But not all displays are like that; eBook readers and my Garmin watch both work best with reflected ambient light.",
"The original Gameboy used what is called a [Transflective display]( URL_0 ). It has a regular LCD on top like most display today but on the backside, there is a layer that reflects light and let light through. It is like a two-way mirror but not specular have defused reflection like a white paper That makes it possible both to illuminate it from an external light source and from a backlight. A display that only uses back illumination is called a transmissive display, this is the common type. The advantage is that it works fin in direct sunlight and it will then use less power because no backlight is needed. The problem is that that if you do that the color will look a bit washed compare to a display that only is illuminated by a backlight. So unless you are it very bright sunlight a transmissive will look a lot better than a transflective display. Because the phone is mostly used out of direct sunlight they use a transflective display. n You can look at the difference the technology in [monochrome displays]( URL_3 ) and [color displays]( URL_2 ) and there is a quite clear difference. If you look at a [Gameboy display]( URL_1 ) it is quite clear that the display is not very good. There is not a lot of contrast in the display at all Translefective displays are used for applications where sunlight usage is a lot more important than good color reproduction. The monochrome variant is quite common and it what you see in for example wristwatches. I have a handheld Garmin Oregon 450 GPS with a color transflective display. It works perfectly in sunlight but the display looked washed out and I would not like to have it on my phone. You can compare it to the touch screen on the GPS. It has a resistive touch screen so it works by pressing anything to the screen so gloves are no limitation like on phones with a capacitive touch screen. It also works fins if it is wet and that is relevant for a device that is watertight and is used out when it rains The resistive is less precise and responsive. So I like the capacitive touch screen on the phone and the resistive touch screen on the GPS. & #x200B; So like almost everything else if there is one advantage there is often a disadvantage so you select the appropriate technology for the production. For a phone, it is a better color reproduction than it prioritized before usage in direct sunlight."
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mrsgvk | Does a battery weigh more when it’s completely charged vs discharged? | Technology | explainlikeimfive | {
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"Yes. Also interestingly, here's an easy way to test AA batteries for charge. If you drop a AA battery onto the flat (negative) end from a couple inches and it bounces, its dead. If it thuds, its charged.",
"Not in any meaningful way. A charged battery stores electricity in chemical bonds between atoms. The same atoms are left after it's discharged, they're just connected together in a different way. If you want to be really technical, energy has mass, E=mc^2. But the difference is so small it doesn't actually matter."
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mryc56 | what are the differences between “ URL_0 ” and “ URL_1 ”? | Are there any advantages/disadvantages to using one over the other, or any functional differences between the two? | Technology | explainlikeimfive | {
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"\" URL_0 \" is a town. When you drive into town, someone asks where you're going. If you don't have a specific house in mind, then they send you to the town's default house, where they want all visitors to go. \" URL_0 /page\" is one specific house within that town. You're driving directly to that house because you know it's the one you want. \" URL_3 \" is a community within that town. When you drive into that smaller community, you're once again sent to the community's default house for visitors (which may be different than the town's default house). \" URL_2 \" is one specific house within that smaller community.",
"page. URL_0 and URL_0 are different *hostnames*. If you send messages to them, you could be talking to different computers, or the same computer. Depends on the DNS setup. The *path* (\"/page\") is how you ask that computer for different things among those it provides."
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