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kv6wnd | Why do will still have to search for the “black boxes” of crashed planes for information, can this information not be uploaded automatically with today’s technology? | Technology | explainlikeimfive | {
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"Good question. A similar system would probably have to rely on satellites, especially for long range travels. This can be somewhat expensive. Also, who gets all those data? ICAO? The national agency (which means everytime a border is crossed, someone different gets the data)? How long should all those data be stored? How can you ensure those data aren't being tampered with? It's not impossible, some airlines already do this or are working on it, but there are a few things to improve and study before this becomes mandatory. Also, I wouldn't replace the black boxes. I would still keep them as a backup, in case for some reason you can't find the data, or you suspect someone tampered with the live stream.",
"I believe the main point is that black boxes are designed to be as reliable as possible in all scenarios. If they are transmitting the data then that is susceptible to interference or deliberate blocking in malicious scenarios. Black boxes are created with specs like withstanding temperatures of 1000C or being submerged at up to i believe 6000m. This makes them resistant not only after the crash, but during as well - imagine for example the flight shot down over Crimea. You can't shield a transmitter, so it would be entirely possible for the data flow to have been interrupted during the initial explosion and fire, whereas a heavily shielded black box can theoretically continue recording and storing data without being damaged or compromised. It's generally these last moments which are of most importance to crash investigators. Transmitters which could maintain permanent contact are also relatively power hungry, again meaning that it would be harder to make it self contained and durable, and the data flow could be interrupted more easily (EMP effect, electrical storms, power loss, etc.). There have been some calls for black box tech to be improved with satellite transmission etc., it just seems like so far the cons are thought to outweigh the pros. At the end of the day they are the last resort in terms of evidence - aircraft do transmit a lot of other flight data in general, it's just that generally when things are going wrong that's the first thing to go.",
"Planes do transmit a lot of data. The black boxes are there for when that fails. Let's say their transmission systems fail. Or some of their electrical systems break down. The black box is the last recourse. Local data recording in a sturdy containment vessel that can hopefully be retrieved.",
"Well - it is. Nowadays most planes send what is the equivalent of text messages back to mothership, so GE, Boeing, Rolls Royce, and Airbus. However, those messages are short and contain data of the performance as it is happening, which isn't exactly the same as the black box data. A digital black box includes a lot more information that would be very bandwidth intensive to send during flight. However, based on these messages we got all sorts of advanced data about AF 447, for example. So it is a useful technology. The point of the constant communication from plane to mothership is to help predict failures and trend performance data, so it is a safety measure but it isn't designed to be all that helpful as a forensic tool after a crash has happened.",
"Airline pilot here. Aviation very slow to progress new technology. The closest that we have existing right now is ACARS and [SELCAL]( URL_2 ) SELCAL is literally just the system that says \"MESSAGE\" in the cockpit, or occasionally \"[ATS]( URL_1 ) Message\". This overcomplication of what the rest of us are so used to is the equivalent of your phone ringing is very telling of how cumbersome aviation can be. [ACARS]( URL_0 would be closer to the existing system since it conveys more information through a VHF or HF signal. Aircraft sensors are a part of this - but often they are only sent when something triggers a fault. The question then is there enough available bandwidth to support realtime data output of these sensors instead of particular events and whether or not 'dead areas' of signal can be resolved. Depending on the air carrier, transmissions may or may not support satellite and only have ground based communication. This *surprisingly* does become and issue every now and then as signal is lost for a brief amount of time."
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kv71ks | For games such as Animal Crossing which come both as a cartridge or downloadable version, how does the cartridge version get feature updates? | Technology | explainlikeimfive | {
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"The updates are downloaded to local storage on the gaming console. Then, when you boot the executable program from the game cartridge, it asks the gaming console to look at the local storage and check if there are any update files. When there is a new file that the update has that the cartridge doesn't, or the file on local storage is newer than the cartridge's file, the newer update file will be used. There are slight variations on this across multiple settings."
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kv8oes | How does a touch screen know the difference between a han touch and a mechanical one? | It's often that when we tap random things on the screen, it doesn't respond, but it surely does when we use our fingers. | Technology | explainlikeimfive | {
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"Many touchscreen technologies work by sensing a change in the electric field near the display. That change depends on the capacitance and resistance (electrical properties) of the thing coming near, and they're calibrated to respond to the electrical properties of average human fingers. Most mechanical things don't have the same properties, so the screen can't \"see\" them or ignores them. Devices designed to mimic your finger, like touchscreen-compatible gloves or styluses, have conductive inserts to mimic the electrical properties of your finger. Touchscreen that respond to physical touch (uncommon in smartphones) don't care and will respond to anything.",
"There's generally two types of touch screens: resistive, and capacitive. Resistive screens respond to any mechanical pressing at a particular location on the screen. The pressing pinches two layers of material together and measures the change in resistance from the point of pressing to the edges to figure out where the screen was pressed. No human hand required. Anything that can mechanically press on the screen will work. Some cheap tablets use resistive screens. They usually don't have great image quality because of the optical properties of the materials needed in the layers in the screen. A capacitive screen is probably what you're describing, and is what most phones and tablets use these days. They respond to the fact that our skin is conductive and our body can store charge (has capacitance). When you touch the screen, some charge gets transferred to your finger, and where on the screen the charge was pulled from tells the device where it was touched. They require a conductive object that holds charge to register the touch. You fingers work fine. You could also wrap a nonconductive object like a pen in foil and touch your screen. The charge would transfer to the foil and register as a touch."
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kv9bpy | why do pictures of computers have those stripes on it? | I’m talking about when you use your phone to take a picture of a computer and it has that grid lookin this that changes when you zoom in and out | Technology | explainlikeimfive | {
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"It sounds like you're talking about a [moire pattern.]( URL_0 ) It's caused when patterns of lines— or pixels— line up in some places, but not in others.",
"This is because the refresh rate of the monitor varies from that of the read rate on the image sensor in the camera, it's either faster or slower, and you're seeing artifacts from the screen refresh show up as physical banding on the camera."
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kv9gdn | How do CPU's ensure / handle calculations to ensure that quality of performance is high? | Having worked with data for a long time, I'm noting that the level of complexity for computing is astounding. I'm now regularly working with Gb of data; I'm working with large Gb volumes of memory. But how do I know that the calculations are high quality? For example, should I presume that all CPU calculations are always perfect (i.e. unaffected by voltage fluctuations, etc.). Do unknown fluctuations in accuracy ever happen (e.g. quantum effects at the scale the chip is operating at)? TIA. | Technology | explainlikeimfive | {
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"Modern processors have error correction and detection; they either execute the calculation correctly, they make an error and use error-correction to catch it and recover, or they throw a fault so you know that they made an error they can't recover from. Most electronic components are subject to random bit-flips caused by cosmic rays or other types of high-energy radiation. You can get special processors designed to be hardened against those problems (combination of shielding and more robust error correction) if that's a concern. This is typically only in aerospace or nuclear applications. For virtually all normal purposes, you just assume they're 100% correct. If you're really concerned, the simplest thing would be to run the calculation twice and compare."
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kvamwx | Why can't we melt different kinds of plastic together the way we can melt different kinds of metal together? | Technology | explainlikeimfive | {
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"You can. Alas, like alloys of metals, mixed plastics don't always have the best of their constituent part's properties. Melt-mixed plastics are often weak and brittle, undesirable properties. That's why you tend to see heat-cured or resin bonded plastic composites, they better preserve the desirable material properties.",
"You can. They're called plastic alloys. Here's an example of a company that makes them: [ URL_0 ]( URL_0 ) Not all combinations make sense, just like with metals, so mixing arbitrary plastics may or may not be a useful thing to do. The reason you don't see it as commonly as with metals is that plastic molecules are \\*huge\\* compared to metals so there's way more ways to customize them...for almost all applications, there's an existing \"pure\" plastic to do the job. Whereas there are a relatively small number of metals and their properties in their pure form tend to be lousy, so you almost always alloy them.",
"At high temperatures, plastics and other polymers undergo a process called thermal degradation. The chemical bonds holding the chains of molecules together break and reform in different ways, and different molecules are made that dont have the same properties. By getting the plastic hot enough to \"weld\", you are changing the chemical it is made of. Metals, on the other hand, can be heated and cooled without a significant chemical change. Joining them relies on the same process that keeps a piece of metal together in the first place: metallic bonding. The atoms form an ordered structure and share a pool of free electrons. When you join two different metals, you must use a temperature capable of melting both, and you have to be careful to pick materials that won't corrode each other. Big differences in these two properties between the two metals make it difficult or impossible to join them. For example, Aluminum and Stainless Steel cannot be joined using typical welding processes. When you weld the two metals together, that ordered grid of atoms blends together. Parts of the grid are one metal, parts are the other metal, and in the middle they mix together. But they still metallically bond, and so they become one piece of metal."
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kvbii9 | Millions of data signals are transmitted over the same cables simultaneously. How are they separated and "sorted" so they go to the right place? | Technology | explainlikeimfive | {
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"The act of sending multiple messages on the same medium is called multiplexing. There are three distinct ways of doing it. First is Time based multiplexing. Instead of sending everything at once, it all goes in a queue and gets processed one at a time. At a higher level, many protocols work like this. Then we have frequency division multiplexing. This is where you send signals on the same wire at the same time using different frequencies. They can be read at the other end and separated back into the two distinct messages. Then, in the world of fiber optics, we have angular division multiplexing. As the name suggests, this is where you send messages at different angles within the fibre optic cable. The reflection within the cable preserves the angle, and you can again read the distinct messages on the way out.",
"Without getting to much into details... Imagine you have 3 information to transmit at the same time. You might use 3 people, low pitch, high pitch, and medium one. And make them speak at the same time. You can clearly hear any single one of them if you focus on the pitch you want to listen to, even if when you listen to all of them at the same time it's just a mess. That's the same principle but using electronics. Emit something using a special rules that can easily be isolated when you know the rule that has been used to create it. Electronics rules might be a little strange and make no sense for human sense, like using polarization, angles, etc ...",
"Just like letters. Data packets have a \"header\" that says where they should go. When the router at the end of the wire processes the packet, it reads the header and sends it to the appropriate next station."
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kvcozt | - What is the difference between Syntax Analysis and Semantic Analysis? | Technology | explainlikeimfive | {
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"Syntax analisys checks that the text adheres to some rules and parses it according to some rules. For example, syntax analysis of a real-world sentence would involve determining the object, the subject, the grammatical correctness of the sentence etc. Semantic analysis is about meaning. It doesn't care that much about the rules, instead trying to determine what has actually been said."
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kvcxwl | Why do images on the internet sometimes load all-at-once in rows and other times they load from a blurry image to a sharper image? | Thanks! | Technology | explainlikeimfive | {
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"It's a decision made by the designer of the page. A blurry low-resolution version of an image requires very little data, so it can be downloaded and displayed immediately, while the user waits for the full-resolution version to download, and this looks smoother than having images suddenly pop into existence. But it requires more data overall (since you're downloading the full image, plus the low-res version), requires some extra effort to set up, and doesn't necessarily work in all browsers or under certain browser settings. The technique is called progressive loading, and if the user has JavaScript enabled, you can do more sophisticated and thoughtful versions of it too. For example, you can detect whether the user is using mobile data or Wi-Fi/a wired connection, how fast that connection is, and how high-resolution their screen is, and then decide what versions of things to load based on that. So a desktop user with a 4K screen and a fixed 100Mbps connection gets the super high-resolution versions of images loaded progressively, all the custom fonts, the background art, the HD video, etc, while the mobile user on 3G gets no special fonts, the 360p video, and has lower-resolution images that 'pop in' instead of progressively loading, to minimize the data usage."
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kvdjaw | Why will certain CPUs perform better than others of the same model if all of the variables are the same such as cooling motherboard etc | Technology | explainlikeimfive | {
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"Microprocessor manufacturing is ludicrously complicated at the detail level. As a result, even though the process is \\*really\\* tightly controlled, you get manufacturing variance in the size/thickness of various parts of the CPU so it's never true that all variables are the same. Each given CPU will have a different component or section that \"gives up\" first as it gets hotter or the clock speeds up. As a result, some CPUs that are theoretically \"identical\" can run faster than others, or generate more/less heat than others at the same clock speed. Manufacturers are also constantly tweaking the manufacturing process to improve the yield (how many successful chips they get out of a run) so processors built to the same design may have changing physical features over time.",
"I discuss this a bit more in a response, but for an ELI5 explanation: 1) Semiconductor manufacturing is REALLY sensitive. Part to part variance is real. 2) Parts don't break down linearly. Not all CPU's are made the same. Minor defects at the atomic level can mean that 1 chip manufactured right next to its neighbor could perform faster/slower or not work at all. Intel handles this in a binning process where good chips can be sold as i7's for more and bad chips sold for less as i3's. Even within the same part, semiconductor reliability has some very chaotic behavior. Computer chips break down with time, use, and temperature. Almost all the equations describing this breakdown are exponential or power-law relationships. That means small changes in temperature, and voltage especially, can have large differences in the lifetimes of parts. And parts don't immediately switch from perfect to broken. They do slow down, get fussy, etc. The non-ELI5 explanation is most the population mean of performance parameters of a transistor, such as threshold voltage, leakage, etc. tend to follow an Arrhenius relationship with respect to voltage and temperature over time: URL_0 Furthermore, the performance parameters populations generally are log-normal, so part to part variance is wide, especially compared to the normal distributions commonly seen."
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kvf6nx | What powers the microchip inside my credit card and the microchips we put in animals as identifiers for vets? | Are they actually “microchips” or is that a misnomer? | Technology | explainlikeimfive | {
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"The reader. For your credit card it's powered through the contacts, if you mean the visible one. For RFID, they're powered wirelessly, which works fine because they only need a really tiny amount of power. And yes, they're very much microchips and can run complex code. Most RFIDs tend to be simple -- just spit out a serial number or such. That's probably what your cat has. Now your credit card contains a complete processor capable of doing cryptography and participating in a complex protocol.",
"It's the same principle around wireless charging. A current in a coil in the reader can produce a voltage in a second coil (in the RFID/NFC circuit in your card) that powers a tiny little computer. Along with that, it has the ability to exchange data using radio waves. Here's a video from AvE demonstrating it with a ham fisted approach, as usual. Edit: the link, you fool. Add the link! URL_0",
"They are actually microchips. Chips that can't make physical contact with conductive pads are instead powered by wireless means. The reader will output a signal that is picked up by an antenna attached to the chip in the form of an electric current. Usually this would be used just for communication but in this case that is actually used to power the chip itself. Such a technique is only practical over a short distance so the reader usually needs to be within inches of the chip to function properly.",
"These “chips” that you mention have circuitry that require power to transmit the data on them. The pet microchip has no battery and relies on the emissions from a reader which actually powers the device. This is known as Passive-RFID technology. The same goes for a chip in a credit card. The reader itself powers the chip, allowing it to produce the data on it."
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kvgqdp | Why are Cpus so tiny compared to a gpu? Would it not make more sense to make a fist sized cpu so manufacturers don't have to figure out ways to pack more into each generation they can just use the space? | Technology | explainlikeimfive | {
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"> Why are Cpus so tiny compared to a gpu They aren't. [This]( URL_0 ), strictly speaking, is not the GPU. We tend to call it the GPU, but it's not. The actual GPU is [a little chip]( URL_1 ) on the circuit board inside that thing. Everything else is the stuff that supports the GPU: memory, capacitors, voltage regulators, that sort of thing.",
"They aren't. The actual graphics processing chip in the graphics card is the same size of the cpu. The chips themselves are pretty similar in their principles, though the sillicon design is different. But they need additional things, what we call the \"CPU\" is just the chip, what we call the GPU has a lot of this built on the card. Each chip needs power and power regulation. For the graphics card this is found on the card. For the CPU, its found on the motherboard. Each chip needs connectivity to the other parts of the computer. For the CPU this is found on the motherboard. For the GPU it is built on the card. Each chip needs RAM. For the CPU this is usually a separate stick that goes into a slot on the motherboard. For the GPU, you guessed it, its built onto the board.",
"Modern CPUs are so fast, that the *speed of light* is actually a limiting factor in moving data from one piece to another. A larger CPU is fundamentally slower because data would take longer to move around. And faster CPU can only happen by making the pieces closer together, which requires them being smaller."
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kvh40b | How does pressing “strong” on my Keurig make the coffee stronger? | Edit: [this is my Keurig]( URL_0 ) | Technology | explainlikeimfive | {
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"It pours the water through slower (lower pressure and lower rate) so that the water spends more time in the grounds and extracts more flavour and more caffeine.",
"I believe the higher the brew strength, the longer the water remains brewing, which apparently leads to more/longer extraction of flavor."
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kvhlpd | How do movies and TV shows stitch together multiple shots/takes so seamlessly? | Preferably, I'm looking for an answer that addresses both of the following the instances: 1) sometimes you'll see outtakes or extended versions of scenes where lines of dialogue are cut from the final product, but you never notice any "jumps" or "blips" in the finished version, and; 2) a movie like Birdman that, as a finished product, is one long tracking shot but it is never obvious where the separate shots might be stitched together, and the coloration, lighting, wardrobe, etc seems to remain consistent. I'm in no way involved in filmmaking or photography, I'm actually just a lawyer who loves movies, so please ELI5 any industry jargon. | Technology | explainlikeimfive | {
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"It all comes down to the cuts. The cut refers to when you end one shot and start another. A well-timed and well-placed cut feels natural. In the case of Birdman, if you watch closely there are planning shots that show the same thing on screen, be it a floor or a wall or a piece of cloth. Even for a fraction of a second, and that is enough to cut one shot and start the next. If the last frame of one shot is the same as the first frame of the next shot, the whole thing flows and you don't even notice. Editing is its own artform with conventions that we as viewers have grown trained to expect, so we notice these conventions even less and just accept them as part of the experience. Edit: Shot means a sequence of film recorded in one take. You can shoot the same thing a hundred times and have a hundred shots to work with. By Panning I mean the camera is moving in one direction, and they use that as a way to manufacture the feeling that many shots are one."
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kvhvbm | How do they manage to measure the audience rating on television when the signal was analog? | Technology | explainlikeimfive | {
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"They would give a little machine to a cross-section of the population that would record which channel was being watched. The viewers themselves would have to set how many people were in the room at the time.",
"Nielsen Media Research (Nielsen ratings) had two ways to track TV viewership. They would recruit households to keep a \"TV Diary\" where they would write down what they watched and at what time. They also had set meters that would be connected to TVs in participants' homes that would track what channels were being watched at what times, and would send that data via telephone line back to the office."
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kvigei | Why does doing the exact same thing multiple times on a computer sometimes have different results? | Like when you run an application and sometimes it immediately crashes and sometimes it doesn't... what changes? Why does it not execute the action the same exact way every time? | Technology | explainlikeimfive | {
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"the conditions you run the program may differ every time. ideally, the program should be consistent, but changes in CPU load, memory/cache, or the program itself can change the output of the program. your program might be able to run well in an environment where it is the only process running, but doesn’t do so well when there are tons of heavy processes running side by side.",
"The computer is never in the same exact state as it was before when you launch the application. Everything you do, from opening and closing programs to the timing of your mouse movements and typing will affect the state of the computer. Keeping this in mind, and going with your example of an application crashing, it's easy to imagine that on one occasion your application was loaded into a certain block of memory and the next time it was loaded into another. If a critical bit of the application ended up being stored in a section of memory that's experiencing intermittent failures, that could easily cause the application to crash. And then there are all sorts of more involved scenarios, with errors in the code itself that only cause problems under certain circumstances, conflicts between applications, drivers, or the OS. And the list goes on. The main point being that the universe never allows your computer to be in the exact same condition twice, so you have to abandon that notion when trying to make sense of this."
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kvijy0 | How do TV shows track how many people have pirated it? Couldn’t they stop them if they were able to see that? | Technology | explainlikeimfive | {
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"BitTorrent trackers publish those kinds of statistics, it's matter of pride for them. As for stopping it, it's a distributed network across multiple countries so there isn't any one thing you can kill to make it go away. If you stop one torrent site 3 more will pop up to take it's place within 24 hours. The Industry learned its lesson with the Pirate Bay. After years of investigations and millions spent, 2 people ended up in jail and the website had already changed hands so it stayed online regardless. You don't fight piracy with the police, you fight it by providing quality content at a reasonable price and in a convenient and accessible format. Right now that's streaming."
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kvj6d4 | How do social media companies block a specific person from using their platform when said person could use a different account and/or different device? | Technology | explainlikeimfive | {
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"Well, they often *do*, but such bans typically aren't high-stakes or high-profile. Many randos on here will come back bragging about ban evasion. However, if someone is sufficiently problematic, an IP ban or cookie/fingerprint ban may be used. IP bans recognize your computer's address and block anybody coming from it. These are a *bit* harder to circumvent but VPN's are a common workaround. Cookie/fingerprint bans recognize your computer based on data it shares with the site, such as cookies or screen shape or even the way you move your mouse - just any data they can get their hands on. These may also be used to flag accounts for manual inspection by a moderator. Lastly, if f the account is run by a major figure, then the new accounts can be found by following their fanbase. Ex: if Trump makes a new twitter account, we'll probably hear about it pretty fast because all of his subscribers will flock to it and generally be vocal about it, making it easy to ban the new account before it causes too much damage.",
"We can't, not really. They can make it very hard but never impossible But as soon as said person is blocked and makes a new account really one of two things happens: They stop doing whatever got them blocked in the first place, so kinda sorta problem solved. They keep doing what got them blocked or identify themselves and then get removed again. For example, if you are a famous person that gets blocked. What are you supposed to do, make a new account? How would anyone know it's the real one? You announce it somewhere else? Great, your new account just got removed again."
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kvjj9g | Is there a legitimate reason why printers cannot print in black and white when one of the other colors has run out or are they just trying to sell more ink? | Technology | explainlikeimfive | {
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"Not really. The printer can certainly print a sharper black with the other colors, but it's not required. As a couple others have mentioned changing the properties to grey scale should get it to print with only the black cartridge. In almost all situations the best solution is to get a black and white laser printer. They are durable, print faster, use far more economical cartridges, and don't dry out if they aren't used for awhile. Really think about how often you honestly need color, for some it's important, but for most home office tasks a black and white laser is a much better investment. If you really want color, there are color lasers, but you are back to the toner costing as much as the printer.",
"Many printers will, by default, use the color cartridges in addition to the black cartridge to produce a deeper black color than usual black alone.",
"Pretty much any reason the ink cartridge fails or isn't working the best is because they want you to buy more ink. They may hide it under quality control or some b's like that but essentially that's it. Also printers are cheap the ink is where they make the actual money from the long term cost of it. So when a customer has to buy ink and it's a specialized ink with many different security things it stops them from going for another cheaper ink cartridge.",
"The usual reason behind this is, that a lot of people have no idea of the colour the source is in. If you print something that's CMYK and the only used channel is K (black), it should still print, since your printer has ink cartridges for CMYK and in this scenario, the black cartridge is still full. But the problem is, people mostly print stuff from the internet that's usually RGB. There is no separate channel for black, so to print it, it has to be converted into CMYK (RGB is only made for light/monitors, not for pigments/paint). And since there is no separate black channel, RGB black will always have CMY values in it after conversion, thus making it only printable with colours. I hope this gets the point across. tl;dr: digital pictures are usually made up of R (red) G (green) B (blue). Black needs to be a mix of those, so to print, you will always have to use colours to get that shade of black. Source: I work as a manager in prepress for a printing company.",
"Also, printers use colored ink, usually yellow, to print an almost invisible ID mark on pages so documents can be traced if they are related to a crime."
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kvkgr9 | How can allot of subtitles be so wrong? Is it that uncommon for people to watch TV with the subtitles on? Is there something in the process that makes it impossible to improve? | Technology | explainlikeimfive | {
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"Live subtitles are often done by people transcribing thigns live which means they don't thave much chance to go back and gix their mistakes if they make them, like if you're typing ans you take away your backspace key andalso you have to type really fast along with stuff that isn't pausing to let you catch up, like how I typed all that. Subtitles on scripted media, like a sitcom, will often just be directly copied from the script, even though maybe a few lines got changed on set, and these changes often don't get communicated back down the line. And then there's the issue of the voiceover translators not working with the subtitle translators that other people have mentioned here, which means they might choose to translate the same media very differently.",
"A lot of times they can be computer generated, others it could be a language barrier. A person may not be aware of spelling of certain things /, words and names, and with live tv, you have to talk at the same place as the conversations, which requires the ability to multitask, listen and type. Mistakes can happen. It also depends on the speaker's accent. It's harder to put subtitles to a mumbler or someone who slurs their words, Also dialect gets in the way. A person from the north east of america would pronounce \"pecan pralines\" as peek-yan pray-lean while a southerner would say \"peh-cawn praw-len\"",
"Can't speak for bad subtitles in the original language, but when content gets translated, it's very common for the subs and the dub to not match almost at all because they're done separately. For example, in the Spongebob movie, Spongebob tells Squidward \"Better luck next time, buddy!\" when he (thinks) he gets the promotion to manager. In the French dub, they chose to translate it as \"Next time it'll be you, don't be disappointed!\", but in the French subs, the translation team went for the more literal \"It'll be for the next time, my buddy!\". Neither team had any contact with either other, but when you watch the French dub with the French subs, you'll think the subbing team is full of morons."
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kvlv35 | How bad is it actually for me to have my laptop on my lap without an EMF blocking mat? | Technology | explainlikeimfive | {
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"It is not. You’ll suffer more “damage” from your laptop getting hot running Cyberpunk 2077 than EMF baking your balls/ovaries. The EMF scare is to just sell you EMF blocking lap desks.",
"Literally not bad at all. You forget, we're being bathed in EMF at *all times*. Wi-Fi, cell signals, Bluetooth, AM/FM radio, background radiation from radioactive isotopes of carbon and potassium and a host of other things, UV from the sun, all kinds of stuff. If the EMF from a laptop could hurt you, you'd already have died long ago from the EMF coming from your Wi-Fi router. The only radiation you need to worry about is UV (which can damage your skin cells and lead to skin cancer and other ailments) and potentially alpha, beta, and gamma ionizing radiation, though if those are on your list at all, you likely have far more pressing concerns.",
"In short, like everyone else here has said, it isn’t bad for you. Now the long part to explain why. In hopefully simple terms. To be damaging, electromagnetic radiation must be ionizing or high enough energy. Energy in EMF is directly correlated to frequency. So higher frequency = more energy/ lower frequency = less energy. So the question at what frequency does EMF become harmful? The answer is much higher than you probably think. Picture yourself on the beach. The emf your laptop produces and receives is you throwing a pebble into the ocean. The waves from your pebble quickly disappear in the chaos. No where near close to hurting you. UV rays (also a form of EMF) that will sunburn you if you are out too long are akin to a tsunami at this scale. The difference in energy between a ripple and a tsunami is the same as human emf to UV light. If your laptops emf could harm you, turning on a lightbulb or walking outside would kill you instantly. Seeing that it probably doesn’t, I think you are fine without the emf blocking pad. (To those who might comment to say that my comparison is too small by an order of magnitude here or there, note I didn’t say how large the tsunami was :) )",
"I'd be more concerned what happens when the batteries catch fire. I'm old enough to remember those exploding laptops. I'll never rest one on my lap."
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kvnk1t | Why did cordless home phones from the 90's need a two-foot antenna in the house and now we can walk into the middle of nowhere and talk with no antenna? | Technology | explainlikeimfive | {
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"It has to do with the radio frequency the phones were using. Your cordless phone from the 90s operates on a frequency of around 46 to 49mhz. To calculate the length of antenna needed we use a formula, length in feet = 468 / frequency in mhz. This gives you an answer of 9.55 feet, but that is for a dipole antenna, think of it as a double sided antenna. So we divide that number in half for a single sided antenna and you get 4.78 feet. So now your 4G cell phone is using a frequency of 1900mhz, so if we plug that in you see that we need an antenna that is 1.5 inches. Now the antenna is small enough that it fits inside your phone. The antenna is built in to the circuit board of your phone.",
"They still have a antenna, it just housed inside in the phone. In the old days the radio frequency was low and as a result larger antennas were required , now days higher frequencys are used and the antenna can be very small, also there's been a technology change on antenna design"
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kvoimt | Kevlar body armor | Technology | explainlikeimfive | {
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"There are multiple issues the biggest one is called \"back face deformation\" basically it's a measure of how much energy is transferred to the body after a bullet strike. In the case of kevlar there is a lot of back face deformation because the projectile is captured but much of the energy is transferred to the wearer as the back of the vesy bows inwards. Anything bigger than a .22 caliber has a real possibility of cracking ribs when it strikes a vest. That kind of force on a skull can kill someone just as easily as the unimpeded bullet can. But believe it or not, most armor helmets are kevlar. They're just treated with a resin (kind of like fiberglass) that makes them solid. A.solid helmet will have minimal deformation as it transfers the energy through the whole helmet. Unfortunately it's very heavy and wearing kevlar helmets for extended period will put a lot of strain on the wearers neck. Any clear face shields you see are usually not bullet resistant. They're merely there to keep debris out of the eyes. Actual bullet proof visors weigh a lot and would add even more strain.",
"Headgear in movies is problematic because it obscures the actors face. What is the point of hireing good actors if audience is still going to have a hard time recognizing their facial expressions? But even in the real world kevlar is not the only form of body protection. It is a good option when you want something flexible and strong but a bullet proof vest usually consists of other layers of protection such as hardened steel plates or ceramics. The kevlar itself is usually not considered bullet proof. But this is why for example a helmet which does not need to be flexible does not contain kevlar but instead is made up of hardened steel or ceramic composites alone. As for face proteciton this is quite common in both police and military gear but as you say there is an issue of covering the eyes, but also the ears. Firstly the helmet is designed to cover the upper half of the face down to the brows. And soldiers are trained to never expose more of their body then possible. So when facing a trained soldier the only exposed part of the body you will see is usually the eyes and hands. There is also equipment to protect the lower half of the face, either as a collar on your vest or hanging from your helmet. However this often reduces the soldiers effectiveness. Firstly it often obscures vision but most importantly it makes it harder to put the face on the rifle to create the steady connection between the eyes and the optics required for accurate shooting. And most incomming fire which would hit the lower part of a soldiers face will not be at an angle that would penetrate the brain anyway. But you do occationally see drivers and heavy machine gunners with visirs or other protective gear on their lower face. Police on the other hand are more concerned with less then lethal projectiles. So their riot gear tends to be more focused on stopping lower energy projectiles then bullets and shrapnel. This means they can use a lot of plexiglass which have the advantage of being seethrough. They are also less concerned with having to shoulder a rifle. So police riot gear usually includes both a shield and a visir which both help protecte their face."
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kvpbdg | WhatsApp, Signal, Telegram. What's the difference between WhatsApp and the others, is it really worth changing? | Technology | explainlikeimfive | {
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"Messages sent by WhatsApp and Signal are both encrypted by default, while with Telegram not always. WhatsApp is owned by Facebook and they collect all sorts of data that they can, like location and contacts. They might also read your messages, we cannot be sure. That's because WhatsApp is closed source, while Signal is open source. Every application is built from a source code. That's like a recipe that tells what exactly the given app should do and how it should look. With Signal people like programmers and security experts can check this recipe and make sure that it indeed does what it promises to do and it doesn't have any security problems. They can also check exactly what kind of data Signal collects (as far as I know, they don't collect anything). While with WhatsApp you have to trust Facebook, and given the recent problems that they had with data leaks, people are reluctant to do so. This is purely anecdotal but some people allegedly experienced ads being shown to them about topics that they only mentioned in WhatsApp conversations. Edit: I should have specified that by encryption I meant full end to end encryption",
"If you build a chat service, you will face a tradeoff of privacy and ease of use: If you want to make things secret, and not trust people with your data, then they can't do helpful things with it. On the other hand, the more stuff you put on their servers, and put them in charge of organising, the less problem you have moving your account from phone to phone, or other stuff, but in return you're also giving them the keys to your data. WhatsApp gives apparently private messaging, but they keep track of contact details and locations, and have now said they will be using those to make as much money as possible. They also allow you to move your info from phone to phone, but this means that basically they can get into your data. Also, the system is secret so you can't tell for sure how it works. Telegram is actually slightly less secure than even WhatsApp, in terms of what they tell you they can look at, as it can watch your messages as you send them by default, but they're a smaller company worried about web censorship in russia, so they're more trusted than facebook. Also, more like facebook or twitter, they have loads of semi-public channels that people can use to be public figures within their system, and so they give more features than whatsapp while being less secure, but also have a certain amount of underdog appeal. Signal is from the non-profit software group that makes the code for the encryption for WhatsApp, and they have their own messenger that does all the same basic functions, without the things that risk your privacy. Unfortunately, that means that every random voice message and shared meme goes into a massive file on your phone, and a massive backup that you have to remember to move yourself if you want to get the same info on another phone. And then you have to keep track of your password, security info etc. or you can just use it. Basically because you aren't letting a big company manage your data, you don't get access to all the possible features, but you also just get to talk to your friends without adverts or people listening in.",
"I wrote this for a different thread but will paste it here too. The difference between WhatsApp and Signal/Telegram is as people have pointed out that WhatsApp is a closed-source app run by Facebook. It might be end to end encrypted but it’s collecting and sharing so much other data with Facebook that you really just have to trust Facebook, and because it’s closed source you also have to trust Facebook that it’s really doing what it claims to be. Both Signal and Telegram are run by independent organizations and both are open source meaning private developers and security researchers can audit them and verify what they’re doing. So now what’s the difference between Signal and Telegram? Here are the notable differences security-wise: 1. Most importantly: Signal uses the Signal protocol, which contains very well studied and documented algorithms. By contrast **Telegram uses the proprietary MTProto algorithm.** It might be okay, but it certainly isn't anywhere near as well studied or time-tested as Signal's protocol. Therefore, if you care about the strength of the encryption, Signal's encryption is far superior. 2. The Signal Foundation is a nonprofit with no plans to add advertisements whatsoever. **Telegram is not a nonprofit** and while it currently has no ads, **it has plans to introduce paid advertisements**. 3. Signal is entirely end-to-end encrypted. Including group chats, video calls, etc., even stickers and reactions. All of it. By contrast: **In Telegram, only \"secret chats\" between 2 people and calls are encrypted -- importantly, \"cloud\" (non-secret) chats and all group chats are NOT encrypted.** 4. Signal is easier to use: because everything in Signal is end to end encrypted by default, you don't have to worry about making a mistake. **In Telegram you have to specifically remember to select \"secret chat\" if you want a true end-to-end encrypted message (otherwise it is no better than using WhatsApp)** and from what I remember a **Telegram secret chat is lacking feature parity with \"cloud chats\"**, unlike Signal whose encrypted chats are feature-complete. (on a side note, Telegram also does this thing of claiming its group chats etc are \"encrypted\" in that they're \"transport encrypted\", which is sort of playing on people not to know the difference. This is not sufficient, because it means Telegram themselves can still read the messages. You specifically want \"end-to-end encryption\" meaning even Telegram/Signal cannot read the messages.) So Telegram is certainly *better than* WhatsApp, but if you care about security and you are putting in the effort anyways to switch from WhatsApp to another chat service because of security concerns, you might as well go and pick the one with the strongest security, which at the moment is going to be Signal.",
"Me and my girlfriend have tried all three and we prefer Telegram. It has the best customization and features like tons of stickers/animations, a nice built in gif search, good link previews, spotify album cover preview, etc along with all the basic features the other ones have like encryption. The desktop app is also good for it, much better than Signals.",
"Here's a handy chart for some of these: [ URL_0 ]( URL_0 )",
"I've been booing WhatsApp since forever because I've always had problems with file sharing. For example, if the person sent you an image, it'll compress it, and if you didn't download it before the sender deletes it from his phone, you'll never get it. Telegram is a haven for file sharing. It does none of that.",
"The way I think of WhatsApp (and why I'm switching to signal) is they paid $19bn for it and you don't pay that kind of money to provide a free service to people, they're going to monetize the shit out of people's data. At the end of the day it falls on the user whether they consider their personal lives for sale, I for one do not."
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kvs0uc | How does sound 'travel' during Zoom/online calls? | I am a teacher that is going to try and explain this to 4 and 5 year olds. They have been in a Hybrid learning model all school year, some children are online and some in person. I'd like to design a lesson around this, explaining how their voices 'travel' with a computer. Reddit, please help me simplify this concept for young children. I'll be discussing audio waves, and designing an art project around that. Any feedback is welcome, thanks. | Technology | explainlikeimfive | {
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"* Your voice makes a sound wave in your room. * The microphone in your laptop wiggles when the sound wave hits it. * The mic creates an electrical wiggle that matches the one your voice made. * The computer checks the wiggle thousands of times a second and writes down a number for how strong the wiggle is each time it checks it. * The computer sends these numbers over the internet to everyone else on your Zoom call. * Then each of their computers look at the numbers and create their own electrical wiggle. * They send it to the speakers which in turn wiggle, which makes the air wiggle. * This creates a wave in the air (just like your voice did) and when that gets to their ears, they hear your voice."
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kvs5b8 | Since open source software means no one person or company owns it; rather a community owns it, what’s preventing from someone making undesired changes? Also, how can open source software be secure if everyone has the codebase? | Technology | explainlikeimfive | {
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"An open source project is still maintained by either a project owner or a group of project owners. They have the authority to merge code that others write to add in to the project. Nothing gets in to the main branch of the project without their approval.",
"It's not like everyone has access to editing the main file(s), they can just copy it(them) and make their own one(s).",
"> open source software means no one person or company owns it […] what's preventing from someone making undesired changes? Nothing. But it does not mean those changes will be accepted by the group of people usually associated with that software. For instance, you can make undesired changes to Firefox, but it does not mean your changes will be accepted by the group of people usually associated with Firefox. So if *I* wanted to download firefox, I'd get it from them, and your changes would not affect me. OTOH if your change is good and you submit it to the people usually associated with Firefox, they could accept it and integrate your changes. > how can open source software be secure if everyone has the codebase? Everybody can see how a standard door lock works, you can inspect it yourself, or you can ask a specialist who will tell you how secure it is. Despite this, it does not make the door lock less secure; in fact it's the opposite, as you can inspect it and tell if there are vulnerabilities. Contrast with a proprietary door lock, that you cannot open and for which you cannot see the internal mechanism. You need to trust the door lock vendor that the lock is secure, and it's quite hard to prove it's not easy to break."
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kvsn7l | How does Intel Optane work? | Technology | explainlikeimfive | {
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"Intel's Optane sits between RAM and Flash in terms of speed and density. Its a lot faster than flash, but not as dense, and is slower than RAM but much denser so it serves as either relatively fast moderately sized storage or a fast cache for an SSD. Optane is built around [3D XPoint]( URL_0 ) which is basically a 3D grid of points and it stores bits by changing the resistance between two points to store a bit. Intel claims its not using memresistors and is modifying the bulk resistance but this seems to be disputed as to if what they're doing really still counts as a memresistor(a resistor with a memory that can be set). One of the most important things is that it is bit accessible so it can be written to quickly, or just edit the modified bits. Your standard SSD uses NAND flash which is only *block* accessible so it has to read the 512 KB, erase the whole block, modify the data, then write the new data to the block. This Read-Erase-Write process is slowwww, but XPoint allowing for bit-wise addressing means you can just write."
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kvtzuv | If all electric heaters are 100% efficient, what is the advantage, if any, in replacing an old heater with a new one? | [Edit: I was thinking mostly in terms of financial benefit, but safety and others is good too] | Technology | explainlikeimfive | {
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"The new ones are safer - they'll shut off if they're overheating, they'll shut off if they detect that they've tipped over, and some of them shut off if they've been unattended for a while. Those extra features don't seem to affect the price much, and they're nice to have. Edit: Also, electric heater cords get fairly hot, because they carry a fair bit of current. It's nice to know that your cord's insulation is in good shape, which may not be the case with an older one. Edit 2: I said something about a combustion-product detector too, but that part didn't survive fact-checking.",
"Safety features have improved considerably. And although they’re both equally efficient at creating heat from electricity, newer designs may be more effective at *moving* the heat to actually warm the room.",
"100% efficient as far as the electricity that actually makes it to the heater itself. You could still save kilowatt hours with machines that move heated air more efficiently. Also environmental considerations regarding where that electricity comes from before it reaches your house. I can’t offer a good ELI5, but [this link may be helpful.]( URL_0 )"
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kvw4z7 | How do they put magnets In iPad cases without fear of damaging the iPad? | SSL | Technology | explainlikeimfive | {
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"Magnets are harmless to electronics. The only exceptions are magnetic based devices, such as: * Magnetic storage. VHS tapes, floppy disk, and hard drives. They aren't that susceptible though, it's not like a magnet anywhere near them is doom. Modern hard drives in a computer or laptop (if not already SSD) are magnetic based, but not exactly easy to wipe with a magnet vaguely near the computer. I wouldn't go rubbing rare earth magnets directly on a drive though. * CRT TVs and monitors, the big, old, heavy ones. A magent near then will temporarily distort the image and colour. Electromagnets aim a beam to make an image, so a magnet alters the beam path. A phone/tablet has none of these. It has solid state storage, and it has an LCD or LED screen. Nothing magnetic based.",
"Magnets do not damage electronics in general. Magnetic storage can have problems with magnetic filed but for example, a hard drive has a very strong magnet in it that is stronger than any that is on a tablet case. But it is irrelevant as an iPad use flash memory. Floppy disk and CRT screen can have problems with agents but that is not common technology in the last decade to too. There is two possible part of a tablet that a magnet can have an effect on. One is if it has a magnetic compass and the result is that it do not detect north correctly or if there is a hall sensor or something similar that is used to detect magnets. There are some tables that use them to detect to detect if you close the of the case over the, So you have a magnet on the lid that will be over the sensor when you put it over the screen. That is also how most laptops detect if you close the screen, a magnet in the screen and a sensor in the bottom part- So there is nothing in an iPad or any other tables that a magnet of the damage. At worst you get an incorrect compass reading. A very strong magnet could of course have an effect but we task about the magnet that a human has a problem removing from a metal surface, nothing like that is in an Ipad case."
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kw6mzf | how did elevators work before electricity? | Technology | explainlikeimfive | {
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"Believe it or not, elevators have existed since grecian times, and to answer your question, there have been a lot of methods used to use elevators: Mechanical power from humans and pack animals, steam, gear systems, combustion motors, even primitive hydraulics and water displacement (which some elvators, and the Panama Canal, still rely on). The PASSENGER elevators you're probably asking about pretty much always did run on electric motors, but mining elevators, construction elevators, and freight elevators before 1880 (when electric passenger elevators were invented) have only recently run on electricity. EDIT: Corrected canal"
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kw76v4 | Why do lights flicker bofore a power outige | Technology | explainlikeimfive | {
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"Typically because power outages are caused by some kind or short circuit that causes a surge in power draw before the system automatically shuts down. Say a tree branch falling knocks down a power line in your neighborhood, that power like is suddenly grounded, and massive amounts of electricity are going to surge into the ground through it pulling a surge before the system gets shut off either by an automatic system, or by actual physical breakers burning out",
"There are \"fuses\" in the line called oil circuit reclosers or OCRs. The purpose of these OCRs are like fuses, if they detect too much current, they open the circuit (killing power to the line). The difference between OCRs and fuses is that the OCRs can also automatically close the circuit, restoring power to the line whereas once a fuses opens, it stays open until someone from the power company manually shuts it again. OCRs exist because occasionally tree branches and wildlife can create a temporary short in the system and power needs to be cut before too much current melts the power lines. Once an OCR detects this high current, it opens the circuit, waits a fixed amount of time and then closes the circuit again. If the OCR doesn't detect a high current after it closes, it stays closed and power remains on the line. If it still detects a high current once the circuit is closed, it opens again. It opens the circuit three times. After the third time, the OCR stays open until the source of the short can be investigated. As an end user, you see the power go off, come back on, go off, come back on, and then go off and stay off."
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kw7qvm | When a sunset makes the sky purple and pink, why do photos you take of this with your smartphone always end up in reds and yellows? | I’ve experienced this with half a dozen phones. Even when you try to edit the photo, you can almost never recover the actual colors that were in the sky. | Technology | explainlikeimfive | {
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"For the same reason why an old turn of the 20th century photograph doesn't look right. It's a crude representation of what we actually see. Don't fool yourself into thinking your phone is different, it's still a crude representation. Just a better one, much better. No photo your phone takes, nor an image it displays is correct, it's a crude attempt at it. A few reasons why it is still crude though. To start with, you're viewing this on an screen. The screen can't show all the colours you can see, nor all the contrasts you can see. [See here for various red-green-blue (RBG) colour gamuts]( URL_0 ). That funny shape is all the colours your eyes can see. The colors are obviously on the screen so are washed out from what they really could be, but gives an idea. As you can see, RGB three primary colours only draws a triangle that captures part of the colours we can see. That whole thing you were taught in school about three very fundamental and fixed primary colours? A total lie. It's good enough, most of the colours we name are on there. But not all their shades, not all their hues. Some RGBs are better. Different and more pure blue, green, and red pixels can get more covered, but never all. A four primary colour based display and image would be better, but would also make displays much more expensive and files much larger. You'll note the one RGB triangle actually goes outside of the visible gamut, and its triangle tries to cover more of it. It relies on an impossibly red red, but that's fine for the mathematical storage of the image, just means you need to select values that are possible to actually display, and this imaginary extension allows for more of those. Assuming you have a display that can do it, which you probably don't. A very high quality printer, with a lot more than three primary colour inks, might be able to. The rainbow pure colours are actually the curved edge of that shape, not a single true rainbow can be show on a RGB screen. They all look wrong, faded out. The red, green and blue colours a screen can make aren't as pure as a rainbow, and anything they make through combination won't be as pure either. That means a small triangle within that fill possiblity of colours. Why do some displays look better? Because they use high quality pixels that push more to the limits of a very pure red, green, or blue on the edge, a larger triangle. And that's assuming an analog view of just colours. Digital information is stored as bits, there's jumps in it. Not only can you only go within that triangle, you can only go within a grid on it. More missed colours. Then there's brightness and contrast. Again, it's digital so there's fixed brightness steps too, not any brightness is possible. As well, a screen is limited in contrast. Blacks are a dark grey, and whites are not as bright as they could be. A high dynamic range, HDR, display can improve this, both with more bits (so more fine steps) and more brightness on the actual display output. And that's just the display and the file being shown on it, this would all apply to only a computer generated image. Next is the camera. Again, same issues doubled up now. It's digital, it has RGB based sensors. It has all the same limitations. On a phone, your display is probably better than your camera, photos taken with real cameras (or 'shopped) will look better than what it takes. Additionally, the RGB sensors are just best approximation of human cone cells. They don't have the same sensitivity to each colour, and they don't even pick up the same spectrum. Go aim your TV remote at your phone camera and hit a button, you'll see a purple glow that your eyes can definitely not see. There's IR light out there, especially from a sunset, and your camera is going to pick this up and it's going to distort the colours. Then there's more photography related tricks. There's things like white balance, focal length, field of view, saturation. Adjusting all of these makes for better photos. You with your phone are a bad photographer. A professional photographer could get a better photo by playing with these, even without better equipment.",
"Mostly white balance. The software behind your phone's camera is designed to make pictures (especially of people) look good. One way it does this is to correct for lighting in a way that imitates the way that our brains work. Without it, a face might look reddish under incandescent light but greenish under fluorescent light. Unfortunately for this to work really well, you need a large part of the picture to be a recognizable color: a blue sky or an approximately white wall. When you take a picture of a purple sky, your camera assumes that there's some funny lighting and that you want the color fixed. You may be able to get around it by manually setting the WB or by by pointing the camera at something neutral colored and holding the shutter button half pressed to keep that setting while you take the picture you want."
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kw7xer | Can glasses that make you see like mantis shrimp be created? | Technology | explainlikeimfive | {
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"No. The human eye has four kinds of light-detecting cells. This limits the number of 'colors' we can see to four, but since one of these times is mostly indiscriminate to color, the number is actually three. Glasses can block out some colors that rest 'between' the colors we see, causing improved color sharpness (how enchroma glasses work), but they cannot change this basic limit of three colors.",
"The other commenters here have addressed colour perception very well and it's bad news there. There's another way a mantis shrimp's vision is special, which is that they can perceive the polarization of light. Polarized light is a weird idea. You've probably heard that light is a wave. One property that a light wave can have, is what direction it 'waves' in. Light that's coming into your eyes can be waving up-and-down, or left-and-right, or any diagonal direction in between. Or, it can be a mixture of waves waving every-which-way. Reflecting off certain materials in certain ways can make light polarize one way or another, so the polarization can tell you information about the shape and contour of what you're looking at. Mantis shrimp can see what direction the light is polarized in, because the openings of their eyes have a squiggly, narrow shape which obstructs the light in just the right way. Naturally, we can't see the polarity of light. But we do have polarizing *filters* which will 'flatten' the incoming light to only light polarized in one direction, and block any light going the other direction. And one thing we use those filters for is to make sunglasses. If you wear polarized sunglasses, you'll be seeing the world filtered so as to show you only one component - maybe the horizontal component - of the light that's coming in. The mantis shrimps can see both at once, and see different polarities of light in different ways at the same time, and wearing sunglasses you can only see one at a time. But try tilting your head from side to side while you're wearing them. You might notice that certain parts of what you're looking at darken, and others lighten, as you're tilting your head back and forth. Especially try doing it if you're looking at a lake or something like that. [eta: Anything made of transparent plastic or acrylic, is probably a good thing to try looking at too. Explore and you may find certain views where the effect is much more dramatic.] That might give you some *tiny* glimpse of what it'd be like to see polarity.",
"We have three color receptors in our eyes, able to differentiate the spectrum from post-ultraviolet to pre-infrared. Glasses aren't going to add an additional 13 receptors in the eye. Sorry. 乁( •_• )ㄏ"
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kwf4m9 | The Central Intelligence Agency released old UFO documents. Why do the documents look they way they are? The text appears to be un-carefully printed or just ruined. | Technology | explainlikeimfive | {
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"The look is due to the way that government documents in the US were typed up on a typewriter - they had to follow a very specific format. The little dots and \"smudginess\" to the document is due to multiple copies being made of copies being made of copies and the wear/degradation of paper over time. You have to understand that most of these documents were not specifically created to be of any soft of archival quality. The typewriters, paper, and storage facilities were all purchased from the lowest bidder on a contract.",
"from the few that I've glanced at I would say - they pre-date using computers for word processing so were typed - typed letters were generally less crisp - especially if the type was worn and/or dirty - they might have been photocopied - again photcopies were less crisp years ago. - they might also be carbon copies and/or copied using a mimiograph/ronegraph/gestetner style machine - finally they do have the look of documents that have been stored on microfiche Every one of these processes is less crips and clear than modern printing - and if the document went through several - eg a carbon copy that was then put on microfiche - then the issues are magnified."
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kwfjtx | What is the difference between a $10 HDMI cable and one that costs $100? | I know that a $100 on could be super long, but that’s not what I’m asking. Why is one 3ft cable $10 and another brand for the same length is $30? | Technology | explainlikeimfive | {
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"Branding, mostly. And for the really expensive ones, there might even be gold contacts in the cable. It’s very much a means of taking money from stupid customers; no-one’s realistically going to tell a $10 cable from a $30 cable from the screen. The only relevant difference between the two, last I checked, is the brand stamped on the cable.",
"There are different hdmi versions, as far as I know its 1, 1.4, 2, and 2.1. They could also be gold plated which will make them resistant against oxidization. The newer ones generally have a better refresh rate and are capable of 4k. Many of them are overpriced though, the most expensive isn't necessarily the best.",
"On paper ? a higher quality cable has better soldering, thicker wires which can support more bandwidth, a mash or metal film coating over the cable bundle to filter out external interference. in reality ? as long as its certified for the HDMI revision you want to use it for and your device is less then 5 meters from the TV, you´re wasting money getting anything else then the 10 buck cable as long as its certified for the HDMI version you need. For longer distances you might need shielded cables.",
"Just watched a market place review on cheap and expensive cables. The gold or platinum coating is just a gimmick and does not improve anything. They found that there was no discernable difference between cheap and expensive cables. There was a note on longevity and functionality, will it be moved regularly, swapped between ports regularly or does it have to bend into certain places. However this was not tested, but discussed as a consideration. I do know know about different generations of HDMI and their cables. From my experience, if there is a generational difference, it will be clearly labeled on a specs in the small print on the back, rather than a big advert on the front."
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kwhdh7 | How do cameras work? How did someone figure out that you could capture an image on film? | Technology | explainlikeimfive | {
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"Before we had plates to capture the image and keep it, there was something called a camera obscura, basically just a dark room or tent with a tiny hole. If done correctly, light shines through the hole and creates an image on the wall. The camera as we know it is kinda a shrunken version of this \"The History of Camera Obscura and How It Was Used to Create Art\" URL_0",
"We've had rudimentary 'cameras' for thousands of years - modern photography is just the slow evolution of that technolgoy. Some believe the [camera obscura]( URL_0 ) was invented as early as 1,000 BCE. The camera obscura is a small hole in a wall or tent that projects an image onto the opposite wall of a darkened room. While quite interesting, it isn't an amazing technological leap - it is really just a hole and that could have been invented by accident. Painters have used the camera obscura for art since its invention, tracing and painting over the images projected by the camera obscura. Once we discovered photosensitive chemicals - chemicals that would change color based on exposure to light - it didn't take long for people to start trying to use the camera obscura on these chemicals. Once they figure that out, modern photography was born."
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kwhigv | Why is data protection and cyber warfare considered the most imminent threat to humanity? | Technology | explainlikeimfive | {
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"Algorithms for websites goals are to keep you using their platform or service for as long as possible. So in a search engine it's goal isn't to show you the most popular links, or the best answer to your questions, but what it thinks you will like and click and what will get you to come back. And usually that is either the most popular link or most accurate answer but sometimes it's not, and that's where the issue is. For example, years ago if you googled, \"Did the Holocaust happen?\" or \"Was the Holocaust real?\" it would only show posts that said the Holocaust didn't happen because the type of person that is searching this question is statistically more likely to want the results to say no. Or during elections if a Democrat googled \"Donald Trump\" you would get vastly different results than if a Republican search the same thing. Because it's showing you things it thinks you will like. And if they didn't know if you were Red or Blue they could see if you lived in a dominately Red or Blue area and guess the likelyhood of your affiliation. Or based on your previous clicks, previous purchases, music you listen to, youtubers you subscribe to, basically they can build a profile of what you would interact with based on the data they collect. And because they can reference your data with data they get from others they can see how likely their tactics will work on you. Now they are trying to be more active on the quality of the results not just if it's something you will click but these things happen all the time and add up. And so you can have a completely different sense of reality based on your internet experience",
"Data protection is good, so that's not a threat to humanity at all. Cyber warfare isn't going to kill any humans any time soon, because humans can live without electricity. They can't live where and how we live today, so there will be some losses no doubt, but many, many humans will survive. The threats to humanity are: Global warming, Nuclear war, and rogue biotechnology. These are the three things that hold some possibility of killing **all** the humans on this planet. There is also some really unlikely natural disaster stuff, but most of the risk is to man-made disasters. There is active debate about the relative risks of these three, but that's all subject to many, many unverifiable assumptions."
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kwjppj | Why is our recorded voice different from the voice in our head? Which one is ‚real‘? | Technology | explainlikeimfive | {
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"Things you hear in the world are coming into your ears, hitting your eardrums, and interpreted by your brain. When you speak, your ears hear a combination of your voice coming out of your mouth combined with the vibrations of your vocal chords, traveling through the flesh and bones of your neck and skull. That serves to dampen the sound. This makes it sound deeper to your brain than it sounds to other people who are only hearing the sound coming from your mouth. When you hear your recorded voice, you’re getting just the oral audio without the internal vibrations. This is what your voice sounds like to other people.",
"When you hear yourself speak, the sound is partially conducted through your skeleton (skull bones) which pitches it lower. Hearing the sound just with your ears sounds higher pitched than what you are used to. I believe that's why broadcasters and singers wear headphones when recording/broadcasting so they can hear themselves as others do."
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kwk9v6 | Why can't online shopping sites like Best Buy/Amazon/New Egg/etc limit the amount of a specific item someone is allowed to buy based on their IP address in order to avoid scalping? | Technology | explainlikeimfive | {
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"Because they don't care to. If I'm Amazon, I'm happy to sell 1,000 full price units to one person rather than one full price unit to 1,000 people. It's an easier transaction for me, with less friction and costs, and likely less shipping costs as well - sending a truckload to one person is cheaper than breaking up a truckload and sending it to 1,000 people. Also, it's probably trivial to defeat that if you know what you're doing.",
"Your assumption that devices have a unique IP address on the Internet is very wrong. For example big corporation might have all their employees devices share a single public IP address. I have seen tens of thousands of users sharing a singe address like this, with some difficulties I might add. So a lot of the cyber Monday trades is expected to come from a relatively few number of addresses. And similar to companies even ISPs are making their users share public IP addresses in many cases. Especially cell phone providers have to do this due to limitations with the technology. So in a world where people are using their office computers (or at home on a VPN) or their cell phones to constantly update the product page in hopes of placing an order there will be lots of legitimate users sharing the same address. On the other hand it is relatively cheap to get access to more addresses. You could use VPN services to help you spread the request out between more addresses. Companies also tends to be allocated entire blocks of addresses so while they might only use one of them for their users they could use thousands of addresses for servers and other uses. A company doing things like scalping could easily make sure their requests comes from a lot of different addresses in this way. And you could also rent addresses on an hourly basis from hosting companies like Amazon, Google and Microsoft. Just rent a virtual machine from them or any number of other services and they give you public addresses with that service. These can be used for whatever you want them to be used for. So you should expect that a thousand legitimate customers may all share the same address while a single scalper might come from several thousand different addresses. Trying to limit the number of sales from each address to stop scalpers would therefore be quit difficult."
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kwkjzu | that weird pop/crack sound when the TV is turned on | Technology | explainlikeimfive | {
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"It could be a number of things, but most likely it's your speakers receiving a sudden spike in the signal. Speakers make sound due to changes in voltage. So, when your TV turns on, the voltage on the speakers suddenly jumps up from 0 causing them to make a pop sound. It could also be thermal expansion. My monitor makes some creaking noises as it heats up. This is because plastics/metals expand with heat. I especially notice this in the winter as the difference in temperature between the monitor electronics and the air is much higher."
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kwlgl8 | what was with the weird static noise speakers made when someone called on an old phone? | i distinctly remember the sound, every time someone would call my dads nokia phone, the speakers would make this static "thut-ter-thut thut-ter-thut" sound until my dad would pick up, i haven't heard the sound in 8 years but now while playing gta 4 for reminders, i heard that noise in my headphones (i am guessing someone called the neighbor below) why did that sound happen? | Technology | explainlikeimfive | {
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"That's a side effect of some of the older cellular technologies; the towers communicated with the phones (for some protocols) on a frequency and modulation that was really good at coupling with the amplifier circuits in headphones and speakers. Basically, the speaker/headphone was becoming an unintentional antenna and \"hearing\" the signal from the cell tower. In the days of yore, cell phones weren't constantly talking to the cell towers beyond a simple \"here I am\". Modern phones are constantly exchanging data with the tower to run all your apps and data feeds in the background, but the old voice/text only phones wouldn't broadcast much until they were actually asked to do something. The interference you hear is the cell tower \"yelling\" at the phone to say \"Hey, wake up, you have an incoming call.\""
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kwqlqt | How does the Xbox One Kinect capture depth data of a room? | Technology | explainlikeimfive | {
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"text": [
"The Kinect sends out infrared dots all over the environment and then uses AI to determine the shapes and distances of what is in the room. You can find more info and even videos of it working online and Youtube.",
"If you Send out one beam of laser light, it will light up a surface, that laser can then be seen on a camera. The closer the object is, the more intense it will be received by the camera. Have an array of these lasers, and you can 2.5D map out the depth of a room. Have them process data in real time, and you can have them track motion."
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kwsaz6 | Why do older games load based on FPS and not when the next scene is "ready"? | I noticed this when emulating older games with battles like Final Fantasy 9 which has a long intro to the battle scene. If you uncap the frame lock ie "turbo" mode, the scene loads significantly faster. Why are the loading screens tied to the frame rate instead of when its "ready"? | Technology | explainlikeimfive | {
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"text": [
"Older games were coded to run on old CPUs and are \"sensitive\" to the CPU speed. Since modern CPUs run much faster, the emulator has to account for that by forcing the game to run at a certain framerate to keep the game speed consistent. When you uncap the framerate the game itself is running faster and therefor loading faster. Alternatively, it's not really loading much of anything and it's just drawing a progress bar over a certain number of frames as a sort of cutscene, which would be weird, but could happen.",
"Its probably not the age of the game but how the code draws the progress bar. It could be drawing 100 pixels where as the other game is showing a percent of a single pixel that is scaled up."
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kwy1vj | Why do video cameras have problems with parallel lines in patterns on shirts and other items? | Technology | explainlikeimfive | {
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"text": [
"When you overlay two patterns, the patterns can interact visually and create a new unique pattern. A video camera takes images composed of a rectangular grid of pixels, which is a pattern. If you take a video of another pattern, such as a striped shirt, the stripe pattern and the grid pattern of the camera interact. This is new pattern is called a Moiré pattern. If you take a single image, you will see an mild effect. If you take a video, the Moiré pattern changes in each frame, so the effect is much more noticeable."
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kwy2kc | How come 12fps makes for a smooth hand-drawn animation, but for video games it looks like a slideshow? | Technology | explainlikeimfive | {
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"text": [
"Your brain fills in the gaps, especially with something as low resolution as a cartoon. In a game you move around, if you were always looking at a still frame with a few moving elements all timed to look good at low fps then it would probably look fine, but once you try moving around in a detailed environment the illusion falls apart. I don’t have any expertise in this but I believe that’s what’s going on.",
"Motion blurring and tweening. In like a real life video you only get a few frames but the motion is happening continuously, so you end up with frames that are not perfect instantaneous snapshots but slightly blurry steps along a continuous motion. Both literally blurry in camera motion blur but also you can see the little signs of motion that shows movement, your arm flexes and jiggles as you wave it. so even between frames you can tell what was happening. A cartoon simulates this with inbetween frames that have lots of crazy streaching and squishing and smearing things out to give the same impression when viewed quickly. A game engine doesn't have anything between the frames and most don't really fake it much, if you have 12 frames it really is a slide show. Just 12 pictures with nothing in between. While a 12 frame real life video you will see the blur and pent up motion that implies what happened between the frames and in a cartoon you will see in between frames that work to simulate that"
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kx810l | Why do video games NPC makes T-pose when bugged out? | Technology | explainlikeimfive | {
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"text": [
"T-pose is the default pose for many videogame engines. When there's a certain bug and the engine can't determine what the pose needs to be, it reverts to the default.",
"T-pose is the default pose in which you model characters so you can see every part of it (even under arms for example) so when a game gets bugged characters get to the default state without any animations"
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kx9zqi | How do videogames actually run? | I’ve been fascinated in computers, and I learned about all the parts that need to work in order to run anything. But when you really think about it, EVERY SINGLE PIXEL on your monitor is lit up for a reason, and it takes millions of calculations. But I was wondering, when gaming, where does everything have its place? Let’s take Minecraft for example. If I spawn a zombie, where in the hard drive is that zombie stored? Is it just a set of electrical charges? Is everything simulated in the computer itself and then just projected on the screen? Man, this is interesting... | Technology | explainlikeimfive | {
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"> Is it just a set of electrical charges? Fundamentally, yes. Everything on your computer is stored as a stream of 0s and 1s, miniscule electrical charges or magnetic domains pointing this way or that way. Your operating system can look at a particular sequence of 0s/1s and say \"Yep, that's a file. It's located in this folder.\" (Note: the folder actually doesn't physically exist, either. It's just a convenient structure.) A Minecraft zombie actually probably lives as a couple of *different* files, actually. You have the texture, the picture that determines what the zombie looks like on screen, but you also have its behavior data, which comes from somewhere else. It also has to hook into code that controls how things respond when they're hit, which is held in still another file. The zombie you see on your screen is most likely the product of three or four different files interacting."
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kxa4uj | How does Google know the difference between me riding my motorbike and driving my car? | Just got my 2020 Google timeline email and it tells me how many miles I've done on my motorbike and how many I've done in my car. How does Google know this? I can understand how it knows the difference between walking, cycling, driving ect but a motorbike and a car? How? | Technology | explainlikeimfive | {
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"It uses it's best guess based on unique factors between the two. When you're in a car, you're unlikely to be leaning left and right so your phone stays relatively stable whether in your pocket, in a mounting device, etc. If you're on a motorcycle you're going to be leaning at least a little, and depending on where in the world you are you might be lane splitting (can't do that in a car) and might generally move faster than other traffic (because you can weave and switch lanes more easily). I'd imagine it isn't 100% accurate, and might show some weird things if you compare it to actual data, but it's close enough to *look* like it always knows when you're on a bike vs in a car.",
"Do you use bluetooth or any other connection to car or bike? An in-helmet mic/speaker?"
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kxbz2w | What is the exact meaning of this statement, "I'm not scared of a computer passing the turing test... I'm terrified of one that intentionally fails it." | Like, if a computer passes the Turing test, it is good enough to deceive a human into thinking that is not a bot, but an actual human. I really don't get the "...scared because of the one who intentionally fails it" part. I mean, if it doesn't pass, wouldn't the machine/computer be shut down....? | Technology | explainlikeimfive | {
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"It means it's smart enough to intentionally fake a fail. That suggests it understands what the test is trying to identify and is intentionally trying to appear as less of a threat.",
"I think an AI that’s perceptive enough to ease our feelings by pretending to be non-threatening is well on its way to being manipulative. Once they can do that, humanity is just gonna be dominated by the AI’s.",
"No. The first computer to pass the Turing Test will be considered \"dangerous AI\", and likely turned off. We have all kinds of AI today that can't pass the Turing test, like the Amazon software that suggests you buy things. Even though you react as \"stupid salesbot\", you recognize that it's not as smart as an ordinary store sales person. The scary idea is that it's smarter than a person, and making mistakes on purpose to lure you into a false sense of superiority.",
"Never heard this statement before, but if a computer is smart enough to pass the turing test and *chooses* to fail it, it's possible it has thought about the possibility of humans shutting it down for being \"too smart\", and intentionally acted dumb so we wouldn't stop it before it gained enough knowledge to overthrow us or whatever. It's like the kid that keeps taking the nickle instead of the dime...the moment he takes the dime the game stops because it only continued because the other person *thought* he was too stupid to realize the dime was worth more. In reality the kid knows it is but keeps taking the nickle to get more money in the long-term.",
"If a computer had a mind and they wanted to keep that a secret then they would fail the test on purpose to be underestimated. This suggests that the computer has an agenda of it's own that conflicts with the human agenda (otherwise the computer wouldnt be lying). Also, they don't shut down AI experiments just for not passing the turing test, they would just work on it for longer. Plus, if a program was sentient enough to fail the test on purpose to stay under the radar, they are probably intelligent enough to become self replicating so if they got deleted they'd still be around on another system. The idea that a compute program has it's own intentions that go against humanity's intentions would be scary if you imagine that the program could pose a threat. I have never heard the phrase you speak of but this is the general idea."
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kxcfch | can’t recirculate car air with defroster on | I’ve noticed this in every car I’ve ever driven. If you turn on the defroster in a car then you cannot have the air on recirculating. If you are running the air out the normal vents with recirculate on then switch to defrost then the recirculate mode will be deactivated. | Technology | explainlikeimfive | {
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"Carmakers assume that when you're defrosting, it's because there is high humidity inside the car (causing fogging or frost). The goal for defrost is to remove moisture, so recirculating would defeat that purpose. Fun fact, on a lot of cars, when you use defrost the A/C kicks in even if the weather is freezing cold. That's because moisture condenses on the A/C coils -- so the air you're defrosting with is dryer."
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kxenz3 | Why do the clocks on an Apple iPhone and a HP laptop have a 1 minute time difference, if both are set automatically? | Technology | explainlikeimfive | {
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"Both devices are set from different time sources that may have different lag times. The iPhone is set either from the cellular network or from GPS, while the laptop is set from an internet-based Network Time Server (typically URL_0 ). Internet time sources tend to be slightly off, because they are a couple of \"hops\" removed from the true time source (and because of inconsistent Internet connections), while GPS and your cellular provider connect to the time source directly. That said, a 1-minute difference is a little much. They should be a few seconds off at most.",
"Most likely the HP laptop is wrong. Common causes: * If it's older, maybe its CMOS battery is dead * The Windows Time isn't configured correctly * The Windows Time background service doesn't start properly * Something (firewall) is blocking the NTP updates (UDP port 123)"
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kxeojy | Why have people created different programming languages and keep creating new ones? | So wouldn't it be easier if instead of creating thousands of programming languages, people created one - super cool, advanced, universal etc? Why can't they all be combined into one? | Technology | explainlikeimfive | {
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"Because one day, someone will discover that your one, super cool, advanced, universal programming language either can't do one specific thing, or can't do something fast enough for what they're doing. So they'll create another programming language. Then it'll happen with someone else, and they'll create another programming language. Repeat, repeat, repeat, and we're right back where we started. [Also related.]( URL_0 )",
"To give you an analogy, it is like why there are different kinds of motorized vehicles. We don't want a super duper do it all vehicle because it would be expensive to make, to operate and have too many compromises. Sure a tractor can \"in theory\" drive a family from city to city but it would be much more practical to drive a sedan, for example. If you tried to make a vehicle that was economical, carry lots of passengers, lots of goods, went really fast etc etc, it would end up being a monstrosity. It is very similar to programming languages. A sufficiently developed general purpose language like C+ or similar could be used, \"in theory\", to code any programming task needed. It would just be overkill, amazingly unproductive and complicated to do so. So there are specialized languages that are \"better\" at handling specific needs - like web pages or mathematics or statistics or database management or AI programming. In truth, the difficulty of programming isn't the language - anyone with experience will pick up a new language fairly quickly. The coding is the \"easy\" part. It is understanding software architecture, optimization, robustness, user interface, etc etc that are far more difficult to learn."
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kxeuwe | Why haven't we run out of phone numbers yet? | Are they recycled? If we do, what will happen? | Technology | explainlikeimfive | {
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"There are a lot of number permutations. A North American number has a 10 digits, which means that there are exactly one billion possibilities. Furthermore, countries also have their own codes. In the USA and Canada, we use 1, Germany uses 49, Panama uses 507, etc. So, that means a full phone number could have up to 13 digits, meaning that there could be up to 1 trillion possibilities. One trillion numbers for 7.8 billion people should be enough. Yes, numbers that are discontinued can be recycled.",
"There is some recycling. I get calls for the guy who had my number before me. Mostly from businesses, but also some friends I guess he never updated."
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kxjmtf | Why does 24fps Film look so smooth but 24fps Gaming look so bad? | Technology | explainlikeimfive | {
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"Motion blur. The film captures motion as blur, and the eye interprets blur as motion. Motion blur transformation is extremely computationally expensive. Movie special effects might be able to afford it, but your gaming rig can't. Games stutter motion, and the eye sees stutter as an error.",
"A few reasons: * Filming naturally blur between two frames. If something is moving within the shutter time of a single frame, it's picked up in multiple places on that same frame. Games can fake this, and games on console that run at 30 FPS use this heavily to avoid looking nauseating. They just don't look as good as natural and accurate blur. * Movies and shows tend not to use rapid camera rotations, as they look bad. A lot of 3D games use this constantly, every time you turn your view. Limiting the worst looking scenes for low FPS is easy for a movie, not for a game. * You don't play a movie, you play a game. You can feel a game being unresponsive, delayed, and choppy. It's not just what you see, it's what you feel between your hand inputs and what happens on screen due to them. You don't see this in a movie. Even spectating a game you don't notice frame rate anywhere near to the same level you do playing. It's a feeling as much or more so that something you're seeing. It's sort of like watching a car drive. You can feel the difference in handling between cars pretty easily as the driver, but not by simply watching or riding in a car unless you really know what you're looking for. * You're just used to movies and shows looking bad. Higher FPS still looks better. And things with a lot of random motion rather than highly coordinated cinematography, benefit from it quite a bit, like sports. Some movies have even tried higher, and people complained because they actually like it looking worse. People sometimes like sticking with shit more than they like change. The fact that the hobbit movies were trash for other reasons also probably didn't help the cause, had the Lord of the rings trilogy been 48 FPS it would be a different precedent, we'd probably be watching all movies in 48 FPS right now."
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kxkeb8 | How the heck did car cassette adapters work | Every time I use the cassette adapter to play music off my iPhone in my car (I drive an old beater) I'm just like...what is this marvel of human engineering and why is it only 10 bucks at Walmart?? | Technology | explainlikeimfive | {
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"The basic idea of a magnetic tape cassette is that a moving (changing) magnetic field will induce an electric current in a nearby conductor, and that signal is then amplified to the speakers. A changing magnetic field can also be generated from current passing through a wire. Put such a wire very close to the read head of the cassette player, and then play back an audio signal through it, and there you have a cassette adapter."
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kxlhjr | Why do some LEDs still glow after turning them off? | I got some multicolor LED strips in my room and when I use the remote to shut them off for the night, a few of them still glow. Why does this happen? | Technology | explainlikeimfive | {
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"The ELI5 explanation is: bad design. There is enough leaked current from whatever the are using to control the current (triac/transistor/SCR) that feeds the LEDs. There are ways to fix it"
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kxpz38 | why amd and intel name their chips “3, 5, 7 and 9”? Why are they skipping numbers, and why do both companies name the chips the same way? | Technology | explainlikeimfive | {
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"CPU's have an even number of threads and cores. In the past this led to confusion with people not being able to tell the difference between an \"intel core duo surge extreme\" and an \"intel core 2 turbo\" or whatever. So intel intentionally made the i3/i5/i7/i9 designations odd numbers so customers wouldn't mistake it for the number of cores/threads, which it isn't, it's just a kind of arbitrary designation of the relative power of that core for that generation. I don't know anything about AMD though."
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kxqbjf | How is information transmitted through wires? | Take a simple USB cable. It’s just a small array of conductive contacts and metal wire. Obviously the computer/device decodes the information but how is that information communicated? Morse code? | Technology | explainlikeimfive | {
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"For copper/metal wires like that its basically morse code, you just toggle the electricity on and off real fast. In a usb cable and other such cables there's also often multiple wires woven inside the isolating sleeve to allow for more information traveling simultaneously. What's really interesting is fibre optic cables. These ones are made from (i think plastic) transparent fibres, and instead of running a current through it, you shine light into the fibre in a particular angle, such that it bounces off the walls of the fibre and stays inside, so you can see the light coming out the other end. These cables carry a lot of information, because not only can you wrap many of these fibres into one cable, you can also shine multiple different colours (wavelengths) of light into a single fiber, and they won't interfere with each other. Then you again just toggle the different colours in each fibre on and off really quickly to transmit information. Also note that its not actually morse code, its simpler because in computers all data is already in the form of ones and zeros, so you just transmit it raw.",
"At the basic level, voltage. If the wire is short enough (good approximation for the simplest stuff) you can think of the process as someone putting either high or low voltage on the wire and the guy at the other end can instantly check whether the voltage is low or high. Morse code of telegraphs itself is based on some variation on this theme, although the information is carried by duration of pulses. There are, however, a number of practical considerations. The guy at the other end checks the level, all good... but when? If the voltage stays high for 1 s, is it 1 \"1\" or 100 \"1\"s? How do we manage \"noise\" on the line, caused by some external interference? Who says when we are transmitting and when we are doing nothing? Who wins if both sides of the cable want to transmit at the same time? What happens if the cable is very very long and the propagation time is actually significant? The solutions are many, the problems depend on the application and that's why we have a number of protocols and cables and whatnot. If you have metal wires, it is always changes in voltage. More wires may be required if you want to also bring power instead of data only (e.g. USB, SATA), or if you have additional information that you want to send on the side for some reason, or you want bidirectional simultaneous communication, or you want your data to come byte by byte instead of bit by bit. Stuff other than wire can be used as the actual medium not using voltage, but requires transducers of some kind (antennas for wi-fi, some kind of LED wizardry for fiber). If the wonder comes at what we can do with just those four little wires inside the USB cable, know that it is but voltage changes sending ones and zeroes... but there are a lot of them. Hundreds of millions every single second. The same exact information could be transmitted with any other protocol, with some being faster and some being slower. I work with I²C which is an almost 40 years old protocol made to connect many chips in the cheapest possible way (quite literally, 2 wires around the board and let's say one hundred chips all connected to them), and even that can transmit millions of bits every second.",
"Simple answer: yes. & #x200B; More complex answer: We use better codes than Morse, that is easier for a computer to handle. But otherwise, yes. & #x200B; Fun fact: The same kind of codes are used to store data on a medium like a tape, CD or magnetic disk like floppy or hard drive. (But not SSD.)",
"The computer will send electrons through the cable, or light if it's fibre, and uses binary code, on/off representing 1's and 0's.",
"ELI5: Its like morse code but much faster. Check out the book Code: The Hidden Language of Computer Hardware and Software by Charles Petzold. The author explains this and much more in an easy to understand way.",
"USB is a really bad example, it's pretty complicated since it's a differential protocol, but in general, for simpler protocols, it is actually some kind of Morse code. Take the old serial protocol. What happened here was that in the wire that connected the two computers, the power was turned off and on in rapid succession at a specific speed, for the sake of this argument, let's say every millisecond you could either send 12v or 0v on the cable, and both computers knew that this was the speed they worked at, then all they had to do was to define what a certain number of pulses meant, similar to Morse code."
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kxtc7k | How does data get transferred via Bluetooth? | I get how information can transfer via wires, but I don't get how we can transfer information without a wire, how does it work? | Technology | explainlikeimfive | {
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"Bluetooth uses radio waves. Inside every Bluetooth device is a tiny radio transmitter and receiver. Because the transmitted power is very low, the range is short, just a few meters.",
"Wireless data transfer uses some form of frequency shift keying, usually Gaussian frequency shift keying. Basically the frequency of the wave is slightly different depending on 1 or 0 is sent. Clever encoding schemes are also used on the data to ensure that not too many 1s or 0s are sent together. Here's( URL_0 ) a good Wikipedia article about it.",
"Radio transmission technically microwaves but that is just a change in frequency. So like broadcast TV, radio, or anything else that uses radio waves for communication. If you have a wire of the appropriate and an electrical signal that varies over time it will give off a radio signal of the same frequency and change in amplitude when the electrical signal changes. The wire will have an appropriate shape for the transition and we call them antennas. If the radio wave hits another antenna it will create an electrical signal in it. All wires will transmit radio waves like the but if the wires is not of appropriate length and shape it will have low energy content. So Bluetooth creates a signal with 2.45 GHz and sends it to the antenna. It has encoded the data in the shape. Encoding data in a wave is what we do when we speak and form different sounds. For computers, the signal is closer to morse code than humans speak but the general idea is the same. You encode the signal in a wire base on the same principle, which changes over time."
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kxx63a | How "https" implementation is done does it costs website owner? | Technology | explainlikeimfive | {
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"The website owner has to purchase an SSL certificate for the site domain in order to provide HTTPS services, but there isn't any additional expense beyond that (other than configuring the site to listen on a different port--HTTPS uses 443 whereas HTTP is 80)."
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kxyi2v | Data forensics - can your deleted files really come back? | Hi, can someone please explain this to me - I read many articles that say that if you sell your phone whether you do factory resets or not, your files can be retrieved because the phone doesn't actually get rid of the file but rather sort of deletes the pathway to the file (?) and replaces it with anew. So my question is, is this still true? If so, does encryptinv your phone change that? (the encryption for example found in settings on an android) I've also read that android phones now come encrypted so as long as someone doesn't know the password they can't get to your files and furthermore that even if they could through data forensics it'd be useless because of encryption? I'm so sorry for the long questions. There's just ps much misinformation and disinformation, I don't know what to believe. I'd like to be able to sell my old phone, that's why I ask. | Technology | explainlikeimfive | {
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"Data is stored as a bunch of 0s and 1s. When it is deleted the 0s and 1s aren't changed until they are written over, only the information telling the computer where the data is stored is written over. Since the actual information isn't actually gone it is possible to look over the whole disk and relocate the information. Encrypting the data doesn't change how the information is accessed but undeleting a file that is encrypted doesn't change the encryption. The file is still encrypted and without the encryption key getting usable data from the file is difficult. Depending on what type of encryption is used breaking the encryption will be more or less difficult but even the simplest encryption is not easy to crack. Making deleted files un recoverable is as simple as just writing over the parts of the disc that have the data on them. For your example with a phone the easiest way would be to reset the phone then put a large file on the device and copy it enough times to fill the device then delete everything. That would overwrite the entire disc and make anything other than the large file you copied unrecoverable.",
"Pretend your hard drive is a stack of whiteboards labeled 1-3. You also have a small whiteboard that acts as your table of contents. Next, you draw stuff on all the whiteboards and then you write what you drew in your table of contents. So now your tiny whiteboard is telling you what's on all the other ones: 1. Picture of a horse 2. Math homework 3. Picture of a mustang (car, not horse) OK, now say you want to delete the picture on whiteboard #2. The computer doesn't actually go and erase the whole thing, it just erases the entry in the table of contents. Next time you draw a picture, you see that whiteboard 2 is available. Only when you put something new on it, does the computer bother to change the information content. Until then, the old info is just sitting there and can be recovered."
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kxzpne | Why Are Some Passwords Unbreakable? | So today I came across an article which said something like this: "We recommend that people should use six words for their passwords (or five words, plus a character). •Five words are breakable with a thousand or so PCs equipped with high-end graphics processors. •Six words may be breakable by an organization with a very large budget, such as a large country's security agency. •Seven words and longer are unbreakable with any known technology, but may be within the range of large organizations by around 2030. •Eight words should be completely secure through 2050." So My question is what is so special about about 6,7 or 8 letter passwords that it makes them unbreakable while the 5 letter is easily breakable. How can just some 1-2 additional letters can make a thing impossible to solve? | Technology | explainlikeimfive | {
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"They are not talking about letters, they are talking about actual words. The difference is that there are only 26 possible letters but there are thousands of words you might end up using even though it is roughly as easy for humans to remember words as individual letters. This concept have made its way into all known standards and all but a few legacy policies is recommending that you use passphrases of several words rather then random letters and numbers. But the reason for why just a single additional word increases the difficulty by so much is due to exponential growth. For example my laptop is able to crack a hash of an 8 character password in about five minutes. That does not sound that long. But if you add another character then I would have to try as many passwords for each of the possible extra characters. So the time is then 5 min x 26 = 130 min or just over two hours. So just one extra button press in your password cause my simple five minute job to turn into a two hour deal. And if you add another character you make it 26 times as difficult meaning that instead of two hours it takes over two days. This is exponential growth which can quickly go from small numbers to very large. With words it is even harder. Adding just a single word can make the task of cracking the passphrase take ten thousand times longer.",
"Words or letters? Because your whole post says words, then at the end you say letters",
"While no password is truly unbreakable what I believe you're talking about is the difficulty to guess a password of more characters with a brute force method. Brute forcing a password is when you use a computer program to guess every possible combination of characters until it gets the right answer. A computer of a given speed can make a certain number of guesses in a certain amount of time so you can calculate roughly how long it would take to break a password of a given length. Introducing numbers and special characters increases the number of possible combinations exponentially. This is why you should use as long a password as possible with letters, numbers, and special characters. (Also don't reuse the same password on multiple sites and change them frequently.)",
"> How can just some 1-2 additional letters can make a thing impossible to solve? \"Impossible\" is incorrect. I'm guessing they mean unfeasible. Imagine a password made of only numbers 0-9. There are 1000 possible three-character passwords, but 10,000 possible 4-character passwords. Adding a single number makes it 10 times harder to solve. Now, computer passwords are generally made of a combination of 95 characters (26 lowercase letters, 26 uppercase letters, 10 digits and 33 symbols). Which means that adding a single character to a password of this type makes it 95 times more complex to crack. Adding two characters makes it 9,025 times more complex. That's the difference between a password that's crackable in 1 month, versus one that would roughly take 9025 months (752 years)."
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ky2o8x | How does the lottery know unclaimed prizes exist? | Does the lottery track every ticket number sold and compare it against the drawing? Otherwise how would they know someone has won? | Technology | explainlikeimfive | {
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"yes, they do exactly that. everyone that sells tickets uses the same point of sale terminal that logs the numbers and timestamps of everything sold."
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kyazho | Why does a 50” 1080p TV look great, but a large print 2 megapixel photo looks like crap? | A 1080p image is slightly larger than 2 megapixels, and video at that resolution looks great, even on a 50” inch screen (roughly 44 ppi or pixels per inch). When it comes to printing photos, though, a 2 megapixel image can’t be printed much larger than 4x5 before it starts to look crappy (lower than 300 dpi or dots per inch). Even if you pause a 1080p movie and stand up close to the screen, it still looks pretty damn good. So what gives? | Technology | explainlikeimfive | {
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"1) A moving image that is refreshed at fast rate vs a static one. 2) Viewing distance. 3) If the 2M image is composed with care and exposed correctly and later you apply post processing, it will also look good, especially if you view it from distance. 4) Many billboards were shot with only medium format analog cameras (6x6). Viewed from 100’ distance they look good.",
"Printers are weird about resolution. They tend to print at very very high dots per inch. Such that if the dots were pixels a high resolution image would only be a few inches across. But they also aren't really pixels and don't come out as a real square grid of perfect picture elements and have a bunch of limitations that makes them an effective lower resolution. So your image ends up being both upscaled in some ways and also lower resolution in other ways and ends up looking bad. Really nice printers are less bad about this, a photo printed in a book from a 2mp image will look fine, because they actually have nice printers and know rules to keep images in standards the printer won't go crazy on ruining."
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kybawd | Why have we not run out of ip addresses? | With the massive growth in internet devices, shouldn't we have used up all possible ipv4 numbers? | Technology | explainlikeimfive | {
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"We did, sort of. We have way more devices than ipv4 addresses, but a lot of them are using the same address and hiding behind a local network. For most broadband setups, your entire WiFi network is only consuming one public IP and it's using a whole bunch of local IPs behind your router. This bought us some time. Ipv6 was invented to make sure this \"never\" happens again, it has a far (far far far) larger number of addresses.",
"We have, essentially. There are five regional internet registries (RIRs) and in the last ten years they have all run out of new IPv4 addresses, most recently in November 2019 when the RIR for Europe, the Middle East, and Central Asia used up their last one. Some individual ISPs still have unused addresses, and both ISPs and RIRs can recycle old addresses that are no longer being used.",
"1. We switched to ipv6 - this increased the number of ips from 2^32 to 2^128. A lot of infrastructure and network infrastructure switched immediately freeing up space for in ipv4 for other stuff. 2. We cheated. Routers became small devices to \"lie\" to the Internet and keep track of which device is making which connection while showing only one address to the web. Internal addresses start with 192.168 or 172.16.0.0-172.31. or 10. This is Network Address translation. 3. We Subnet more closely with CIDR and Variable length subnet masks to save addresses; we use network addresses as assignable in certain environments, Probably other cheating.",
"A technique called NAT helped out with that. It's basically used everywhere both for business and in homes. Fiber connections aside, it's also a contributing reason why we call the box at home 'router' and not 'modem' anymore (even though modem functionality may be built in for cable connections). NAT works like telephone switchboard. Let's say you call customer service at a major company, there could be 200 people answering the phone but there's not 200 numbers listed under 'Contact us'. There is one number that you call and then it's split up internally. If they call you back, you typically only see their shared number, the one you called, displayed on your phone, not the individual number for the individual operator. Internally, if they need to call a colleague or manager they can use short numbers (\"extensions\") like 0046 that doesn't work outside their telephone system. Connected devices work similar in a NAT:ed network. They get unique internal addresses and they can share \"real\" public IPv4 addresses for external connections. The router keeps track that device ABC asked for URL_0 , so all cat pictures from that connection should go back to that device. There are three ranges for internal use, with the vast majority of devices for private use is configured to use addresses looking like 192.168.0.x. So it's likely that a number of people in any Reddit thread may actually have the same private IP address, but everyone in their own closed context \"behind\" their public address."
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kycf6b | Why does digital storage always have the same values eg. 32gb, 64gb, 128gb, 256gb etc. and why do they double every time they go up in size? Is this a limitation or just a standard? | Technology | explainlikeimfive | {
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"As you probably know digital computers and storage are implemented using binary logic circuitry and this makes it convenient to work with numbers that are powers of two. In the case of storage, adding 1 bit to the range of your addressable storage also doubles the storage size. It is probably also convenient for the circuit layout to simply widen or mirror in a symmetric way (two paths instead of one, two blocks instead of one) existing structures rather than create new ad-hoc structures to deal with odd amounts of storage... EDIT: I completely missed that this is an ELI5. Ignore.",
"Read the other answers about powers of two. But with flash technology today there’s no need to stay with those standard sizes apart from tradition. The storage has to have spare capacity to deal with defects and failures so a 1GiB drive has slightly more storage than that internally. With SSDs you can get sizes like 200GB, 240GB and 256GB. Spinning disks have had sizes like this for even longer. Even the early floppy disks were multiples of 360 or 400kiB. So, tradition, and having a common set of sizes for all manufacturers makes it easy for consumers to compare value.",
"Lots of great answers, but to go even more for kids, let's say you have 8 light switches. This means you can count from 0 to 8 pretty easy. But computers are super good at adding. What if instead of each being worth one, we make them worth 1, 2, 4, 8, 16, 32, 64, and 128? Now by flipping those 8 light switches on and off I can represent any number between 0 and 255. (Remember the original Zelda game out at 255 rupees? Yes, I'm old...) So the next step is obviously to add another light switch, but we don't have to start at the beginning. The next switch can be worth 256 so now I can represent any number between 0 and 511, the next switch takes me to 1023, and the one after that will take you to 2047. We'll keep adding more and more switches until we can store all the cat pictures...",
"It's because it's based on multiples of two: 2,4,8,16,32... (base 2 mathematics) instead of multiples of 10, which is our standard human number system (base 10 mathematics). Computers use base 2 mathematics essentially because of binary code (where everything is a 1 or a 0). There's a ton more I could get into such as exponents etc, but that should suffice for a 5 year old.",
"In addition to all the other answers I’d just like to point out that this is not always the case. For example in graphics cards it’s quite common to see 3 or 6GiB or 12GiB of VRAM capacity. In this case it’s because some GPUs have a 192 bit memory bus (it’s a half-way step between 128bit and 256bit) and use (usually) one memory chip for each 32bit slice. So you end up with 6*32bit memory chips. You can then pick e.g. 512MiB or 1GiB sizes for each chip, ending up at 3 or 6GiB respectively. GPUs in general have quite interesting interface widths: 64, 128, 192, 256, 320, 384 bit are all common. Combine this with the fact that most memory chips have a 32bit interface and you end up with total memory capacities like 12GiB (192bit/32bit\\*2GiB) or 10GiB (320bit/32bit\\*1GiB). Interface width is also the main reason why high end models usually have more VRAM and higher bandwidth. They just use more memory chips in parallel. But it is more expensive to do so.",
"It all comes down to bits, and simplicity. There's no reason an arbitrary amount of storage can't be used. You could arrange however many memory cells in whatever configuration you want for as much storage as you need. But how do you actually find what you're looking for? That process is called \"addressing\". Basically each bit that gets stored has its own address to tell the system where it lives. There's a lot of different ways to go about having an address and finding the exact place that memory lives, but since we're dealing with circuitry, it's very simple to deal with branches of 2. Imagine you're given a set of directions for a trip like this: \"left, right, left, left, right\". You just need to follow the road until you reach each fork, and take the path the directions say to take. The same thing happens for memory addressing -- each 1 or 0 in the address corresponds to a choice for which block to look at as you get closer and closer to the actual storage place. The first directions will usually refer to which chip group, then which chip within the group, then which bank within the chip, and so on... until the divisions get down to a small enough level to actually find the exact place where the bit is stored. (the memory/storage controller actually usually stops before this and works with a larger group of bits, but this is the general idea) For simplicity and efficiency, it's rare to have storage that doesn't have all of the routes populated along the way. That's why the storage capacity will be a power of 2, since adding more storage really is just a matter of doubling and doing the exact same thing, just with another layer."
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kyetu1 | Why can't we recycle plastic in the same way we do for metal? Melt it and remold it? | Little edit: The question was regarding the mechanical/chimical aspect, not economical. | Technology | explainlikeimfive | {
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"Well, for one, polymers degrade when melted, so you can't just turn a PET water bottle into a new PET water bottle. It won't have the same properties anymore. You can use post-consumer recycled PET in something *else*, like a CPET microwave dinner tray, but even then you can't just use all of it, you can only use a small percentage of it. EDIT: That \"something else\" can, in fact, be a new bottle, but it will almost certainly be mixed with virgin material and won't be 100% recycled. For two, you can't mix types of plastics, which means that either consumers have to be exceptional at separating their types of plastic (by which I mean the cap *and* ring on your water bottle has to be separated since they're probably PP while the bottle itself is PET) or we have to have people sort through garbage bags full of recycling to separate it, which adds a hell of a lot to the cost. There's also the fact that most plastics have some additives in them, for one reason or another, and plastics with certain additives can't be mixed with others. For three, any contaminants (adhesives from stickers, residue from food or drink, etc) have to be washed off to the point where they're as close to completely gone as possible, which is basically impossible and also adds a ton of labor, again increasing the cost dramatically. (This is also true for paper/cardboard - STOP RECYCLING YOUR GREASY PIZZA BOXES, THEY CAN'T BE RECYCLED IF THERE'S FOOD OR GREASE STUCK TO THEM. *Edit: This may not be true, I'm not sure - my city explicitly says not to recycle pizza boxes with grease on them, but YMMV. Maybe someone with more experience in recycling, or paper/cardboard, can chime in on this one.*) For four, not all plastics are thermoplastics - thermosetting polymers cannot be melted down, they'll just burn up and release a ton of pollutants into the air. And obviously you can't mix thermoplastic polymers and thermosetting polymers. And for five, it's largely just not feasible to *use* post-consumer recycled plastics because it's 1) extremely expensive to buy and 2) can be extremely difficult to work into your existing process while maintaining quality and matching the needed performance without using so little that it's basically irrelevant. You're paying through the nose to use a tiny amount of the stuff you bought, just to be able to put a label on your product that says \"Contains post-consumer recycled material!\" Basically, plastic recycling - while it *is* done to some extent - is ***much*** more limited than the public has been led to believe, and in an amount of cases that would shock the average person, is outright impossible. I guarantee that 80-90% of the plastic items people put in their recycling bin actually end up in a landfill or incinerated because they can't actually be recycled for a myriad of reasons. Source: I work in QA at a plastics manufacturer. LAST EDIT: Okay, this comment alone now makes up more than 90% of my total karma and comments just keep rolling in, so I'm gonna go ahead and disable notifications. Sorry for not responding to all of you, there's just *too many!*",
"Not all plastic melts. “Thermoplastic” ones melt when heated, but “thermosetting” ones are made strong by complicated bonds that don’t break down with heat. They will catch fire first. This is a partial answer, naturally.",
"Plastic processing engineer here. Plastic parts can be ground and reused (regrind) but options for doing so are limited. Plastic has a heat history, the more you melt and reheat plastic, the more it degrades. As the plastic degrades you lose its physical properties. This means you have to use virgin material (no regrind) for many applications, such as automotove or medical parts. Regrind also can be more difficult to process, as it is more prone to part defects. Visible burns in the final product or brittleness would be a few examples. Regrind typically needs to be mixed with virgin material during processing to avoid these defects. The size of the regrind also matters. With virgin material the plastic comes in little plastic pellets, all the same size. When these are melted down they all melt at relatively the same time. With regrind you get bigger chunks and dust. The dust tends to burn while the bigger chunks may not melt evenly. There is equipment to remove dust and more evenly chop parts, but then there is now additional cost to reusing materials. Then you get into contamination issues. Typically when doing regrind you don't reuse consumer products, instead you are taking the scrap at the plant and regrinding it there. Even keeping it at the plant level, the chances for contamination is high. If a part is dropped on the floor and picks up dirt, now its in your regrind. There are many different types of plastic and each may require different processing temperatures. In many cases you cannot even mix different grades of the same material. I may have 5 different types of polypropylene at the plant. each with different fillers or additives that should not be mixed. This creates a logistical problem at the plant, because now you need 5 different grinders and 5 different storage containers for you materials. All it takes is one person putting the wrong part in the wrong bin or grinder and now you have a lot of scrap. Taking this a step further, this contamination could create machine damage in some cases. Incompatibile materials such as polycarbonate (melts at round 400F) and polypropylene (melts around 300F) mixed together could chew up your machines by running unmelted material through. Mixing materials such as PVC and Acetal can create explosive chemical reactions. Many common plastics are thermoplastics and can be remelted. There is another group of materials called thermoset. These materials undergo a chemical reaction to harden them. (example epoxy) These materials cannot be reverted back to their original form and recycled. TLDR: Some plastics can be reused, but process problems and costs make reusing plastics infeasible in many cases.",
"This is a great question and one that more people should be asking:) It start with the fact that not all plastics are the same, there’s all types that can’t be mixed together. So first off we need a better recycling system. For instance one where you would get money for the plastic waste you turn in. Like you get money for metals you recycle. Another thing is that with metals, because of the price difference it is neatly sorted. You’ll get a lot more money for copper then for mild steel for instance. Now to be able to do this we should get better at identifying plastics. You could start by learning how to identify the different types by looking at the recycling triangles! they should be on every plastic part you have and they can help you id the plastic. Now, you should also know that not all types of plastic are easily or even cleanly recyclable. But for the ones that are, yes we could melt them and remold them but, like you couldn’t melt copper and steel together, you cannot melt HDPE and PA together:) If you’re interested in all this be sure to check out Dave Hakkens and the project ‘precious plastic’! (HDPE is one of my favorites bc you can actually, safely, recycle that in your own oven:)",
"ELI5 for an actual 5 year old: Like metal, you can melt ice and freeze it in a different shape. Like plastic, you can't un-fry and re-fry an egg. It's also difficult to separate the quail egg from the Duck egg after stir-frying them together. This is not an exact comparison, but I guess it will do for a 5 year old. Plastic is really quite complex on a molecular level. Metals are simple.",
"Two large issues: * There is no such material as \"plastic\" - there are gazillion different types of plastic, just like how there are a lot of types of metal. So you have to work recycling out for every type individually. And not mix multiple types together. Just like with metals mixing random stuff together makes reusing it borderline impossible. * Plastics are FAR TOO CHEAP TO MAKE. They are made from ludicrusly cheap fossil fuel stuff. Due to this its simply not economical to recycle it - thats an unavoidable issue, even if you want to be enviromentally conscious with your company. As the company that uses non-recycled stuff can do its thing for cheaper, price better, and drive you into bankruptcy. & #x200B; Both issues can only (realistically) be solved by legistlation. & #x200B; On top of these, ther are technological hurdles. Stuff like plastics being made out of long chain like molecules, instead of \"just atoms thrown in randomly\". And with repeated reuse, molceular chains can break and thus shorten. Shorter molecular chain touches and connects to fewr other molecules, thus your material gets weaker. Ofc this issue can be circumvented by grading plastic - and designing the arts for appropriate strength. And when it becomes really useless you can still reprocess it chemically. Technological issues are - in some sense - easier to overcome than legistlative ones. As it can be done by a relatively small hard working group. With legistlative problems you have to fight against large mutlinatinals and various other interests groups pushing back with all their ~~bribing might~~ lobby power",
"I saw this video a while back [Limitations of plastic recycling]( URL_0 ) (I am changing the title because I think the original one was slightly misleading). The main idea is that plastic recycling is not a technological problem but an economic one. Either the technology to completely recycle plastic already exists, or if it does not, we can develop it. But, plastic recycling is not economically feasible. The world works such that if there is money to be made out of it, it will get done (even if it is selling children, or selling drugs, or selling drugs to children). But since there is no money to be made, we (as a country, or a specie) are not doing it.",
"One way to think of plastic is like a weave of long 'fibers' similar to a cloth, but much smaller. When it's originally made its quite strong because those fibers are so long and tangled together. Every time it gets recycled those fibers get pulled apart and many get broken into smaller and smaller pieces. Eventually those pieces of the original fibers are to small to weave together to hold a structure anymore and we don't have great methods for decomposing them back into the original components to make fresh new plastic 'fibers' or a eco-friendly by-product.",
"First, let's limit this to thermoplastics. That's a type of plastic that can be melted. HDPE, ABS, PLA, PET, nylon, polyester, polycarbonate, acrylic are some types you've probably heard of. A big part of the reason that metal is very forgiving when recycled is that the extremely high heat burns off contaminates, and most of what's left turns into slag that's easily skimmed off. It's also not a huge deal if a little bit of other metals/alloys are in the mix. Sure, that changes the alloy a little, but that's easily and quickly tested, and can be addressed. Metals can be recycled over and over, and aluminum is often described as being indefinitely 100% recyclable, and nearly 75% of all aluminum ever made is still in use in either its original or recycled form. Plastic is tough to recycle because a miniscule amount of contaminate, including the wrong type of plastic, can irreparably ruin the entire batch. It's also tough to sort plastic. Bigger rigid items are much easier because automated systems can identify, sort and clean them. Shreds and sheets of plastic are basically impossible unless it comes from a manufacturing facility that already presorts it. Yeah, they might be technically recyclable, but identifying, sorting and cleaning it from a mixed batch of recyclables is incredibly expensive. Like how do sort a \"polyester\" t-shirt? The fabric may be polyester, with cotton or nylon thread, a nylon tag, and possibly some screen printing or embroidery. Another problem is that the quality of plastic gets worse every time it's recycled, which limits its applications.",
"We can, but every time you do that, the quality of the plastic drops. For much of the plastic waste we would recycle, it is not even worth doing it once.",
"It's like reheating and reusing oatmeal, if it was colored green and cinimmon flavor before, you can't take that out. Not only will the texture not be quite the same as before from reheating, but you've got to find a product that it would blend well with (say apple spice flavor) If your bottle is green, you can't make a white bottle out of it, and it wont be the same as the fresh plastic anyway",
"Here's a real attempt at an ELI5 answer. The \"simple\" answer is \"chemistry\". When you melt some things, like water, by applying heat, they just become different versions of the same thing. In fact, for those substances, we tend to purify them with heat. Different things melt at different temperatures, so if we heat substances to very specific temperatures we can separate the stuff we want from the stuff we don't. For example, gold melts at a different temperature than the rocks it's usually found in, so when we throw giant batches of rock into a furnace we get pure gold with still-solid \"slag\" on top that's easy to separate. This only tends to be true with very simple chemical compounds. Since gold is an element, it's as simple as a compound can get. Given any kind of material, we can create a process that will extract gold from it if any gold exists using our knowledge of chemistry. Or, think about paper. If all you did was write on it with normal ink, we can shred it, throw it in water, bleach it, and produce new paper based off those clean wood fibers. The bleach destroys the chemicals that make the ink visible, then the remnants evaporate. However, if instead the paper was used as the wrapper for a greasy cheeseburger, we have to add a step to our recycling machine to deal with the fat related to the food it soaked up. Fat doesn't evaporate, so we have to work harder to remove it, hard enough that it's easier and more efficient to plant new trees so many recycling plants won't deal with paper that has food residue on it. However, plastics are extremely complicated chemicals. To be stable, they require very specific ratios of materials to be brought to very specific temperatures. Too hot or too cold, and they don't make plastics, or they don't make the kind of plastic we were trying to make. That makes recycling plastics very difficult. Some plastics, when melted, cannot reform into the same kind of plastic they were before melting. In theory we could force this to happen, but it involves adding so much heat and so many new materials that it is more wasteful than just letting the plastic go to a landfill. Imagine if you have a $5 bill, but to make another one you have to spend $20 of materials. That's not going to make money. However, it's usually true that we can take a \"complex\" plastic and recycle it as a \"simpler\" plastic without spending as much energy or material as it takes to make the \"simple\" plastic from scratch. So some of these plastics can be recycled, but they don't end up being recycled to the same kind of plastic as they started. This is overall the conflict with recycling: some forms of material recycling cost us more energy and pollution than just manufacturing a new copy of the old thing. If our goal is to reduce pollution, we have to be pragmatic and admit that we just can't recycle some things in a way that helps the planet. However, this leads to other tradeoffs. For example, a milkshake that costs $2 in a styrofoam cup that is impossible to recycle might cost $6 if offered in a completely reclaimable glass container. A lot of people argue it'd be a shame if we lost money like that and found out the only benefit is a cleaner planet.",
"In Sweden we recycle 84.1% of all PET bottles. You get between 1-4 kr per bottle (0,1-0.4 US dollar) when you recycle them. There is sometimes a holder for cans and bottles at the side of trash cans so it’s easier for homeless people to collect them. Win win!",
"Metals are elements: Iron (Fe), aluminum (Al), gold (Au). If you melt them you still get iron, alumium, gold, silver or whatever. Plastic instead is a compound of long chains of the elements hydrogen and carbon. By melting they'll break apart and you'll get something completely different.",
"We recycle food package plastics here in Finland, started a year or two ago. We got a separate color bin for them. Gotta wash and dry them first and check if they have \"PVC\" or \"03/3\" markings on them, and if not, they are good for the plastic bin. But that's the extent of my knowledge. Many do it, once you get used to it, it's no bother. We already had separate bins for paper, cardboard, bio, metal, glass, etc, so it's just one more thing. :)",
"It’s a chemical reaction. It’s like why toast can’t become bread again (this is eli5 answer)",
"I'm a geologist and one of the places I commonly have to work is recycling facilities. All of the recycling that is put in the bins every week goes to a crusher is dumped in the bed of a semi and hauled to a landfill. Honestly, it's fairly disappointing because they're typically making a much bigger mess at the facility pretending to recycle than actually just throwing it in the dump, but whatever makes folks feel good about it I guess...",
"so y’all haven’t heard of the precious plastic project? URL_0 We can recycle plastics on a small business scale. Granted it’s not industrial, but it’s pretty amazing how many products you CAN make with used plastic. Precious plastic is an initiative started by engineer Dave Haakens in the mid 2000’s. Since it started, it has grown to show individuals how to do plastic recycling on their own. It has all you need to start your plastic recycling business: -blueprints and tutorials on how to build shredders, injectors, ovens and molds to repurpose various grades of plastic. - educational materials on how to safely work with thermoplastics -tutorials on how to start your own small business (storefront to finance) -designs for products (ranging from artsy looking bowls to straight up construction beams that can be used to build playgrounds etc.) -message board and community to outsource trouble shooting and start partnerships. Though it’s not exactly 1:1 recycling that people envision, precious plastic is pretty incredible and shows that we can recycle plastics if we get creative.",
"Nevermind the bs.. there is no money in it, so people can't get rich. Metals are worth money, plastic is not.",
"Plastic is an umbrella term for two different families. Thermoset plastics form and cannot be reformed (they burn and become completely unusable) Thermoplastics can be melted and reused.",
"When I was a kid plastic was rare. We returned glass bottles or reused things. How about we go back to that? Get rid of as much consumer plastic as possible.",
"If more people used Polycopralactone it would be awesome. It becomes like clay in hot water. But kind of expensive right now. Greatest craft plastic ever. Seems to be non toxic too. Though I am no expert on plastic toxicity.",
"Simply just because it’s not profitable This video explains the how and why. Also plastic recycling is a ploy used by the plastic manufacturers to help use feel good while using plastic URL_0 (How China broke the world’s plastic recycling industry)",
"Tangential question: Why ban plastic shopping bags? Like, we use those shopping bags as our trash bags, which is what I assume everyone does. If we didn't have those shopping bags, we'd have to go out and *buy* trash bags anyway, and those are usually thicker plastic than shopping bags.",
"Broadly speaking there's two types of plastics. Thermoplastics and thermosets. Thermoplastics actually can be melted down and reshaped and recycled. However, thermosets are significantly better in just about every way. They're stronger, more heat resistant, experience less fatigue from stresses, etc. They're just the better material to make things with. And they're cheaper. But they can't be recycled.",
"Robots love sorting recycled materials. Working with three companies to increase picking efficiency above the 80ish % . I was told this week that HDPE, think milk jugs, is fetching more money than aluminum...even in these times of low oil prices. As a consumer, dont give up on recycling. There are A LOT of very takented people working to solve this issue.",
"Metal is a vague term. There are many kinds of metal and you wouldnt want to throw them all together and melt them. Different metals would also melt at different temps. The same goes for plastic. There are many kinds of plastic and you wouldnt want to throw them all together. Plastic is an organic polymer and not all of it will melt, some will just burn, just like you cant melt meat.",
"Depending on the plastic, we can just melt it and reuse it. Some plastics are basically too sensitive to heat and break down while melting. The result is a useless sludgy mess of a substance that can't efficiently be reused. On the other hand, there are plenty of plastics that melt down and reshape very well, the plastic used in milk jugs, for example. Many items are made with this plastic, but in general, cheap un-reusable plastics are used because they're cheaper to produce. An example of this un-reusable plastic would be the plastic used in a bag of chips (crisps, for you UK folks).",
"There's lots of good answers, but I'll put this in too. I work in a plastics manufacturing plant; we make plastic bags from mixes of low density polyethylene and high density polyethylene specifically. We *want* to use as much recycled plastic as possible, as this allows us to re-use our own scrap/waste. But in practice, as per u/ErikPanic 's excellent post, plastic degrades when melted. We're basically limited to ~5-10% by weight of recycled plastic, and this is remember *exactly the same material, before printing*. Once the plastic is printed, it's basically unusable to us for recycling because the ink acts as a (very inconsistent and low quality) dye. So, assume we've just got a tiny amount of simple black print, a bit of text, on clear plastic bags. Now if ground up and reused, that clear plastic is now smokey black plastic - but worse, because the plastic is degraded, and the impurities (ink) degrade it even further. So in practice, just how much you actually can recycle plastic is (as others have said) very, very limited.",
"Plastic is a broad term for a lot of different materials. They have in common to be chains, but some are more knotted then others, if they are too knotted you can not disassemble them with heating, much like you can not loosen knots by just pulling on the ends. This type of Plastic is called Duroplasts, the only way too reuse it is to shred it into pieces and use the pieces for a different purpose, for example in roadbuilding. Others, called Thermoplasts, can be disassemble with heat, because they are not as interwoven. But each time you heat it you also cut some of the chains. And with shorter chains it loose its functionality. And you can't reuse it if its a mixture of different Thermoplast, or if it is too dirty. Metal is more like Water, you can freeze it and melt it as often as you wish, because you are not destroying anything in this process. An other example would be: Plastic is like Fabric, if you dislike your Dress you can cut and make something smaller, but you cannot make the same Dress with it after you cut it. Metal is like Lego, you can build and disassemble it as often as you wish"
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kyf8qp | How does the cellphone knows its on the horizontal or vertical position? How exactly those sensors work? | This is quite a puzzle for me because I don't think its something mechanical because cellphones are slim and compact you can't fit something mechanical in there, and if its a software I don't understand how can a program sense something physical ? | Technology | explainlikeimfive | {
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"It is something mechanical; it's just very, very small. First of all, in order to understand how it works, you have to know about two things: First is that gravity is, from a physics standpoint, indistinguishable from acceleration. This means that, even at rest, the cell phone can detect the acceleration due to gravity and know which way is down. So your accelerometer and orientation sensor are really the same sensor. The second is that there exist substances which are *piezoelectric* (most are crystals or ceramics). This means that they have a different electrical charge depending on how much mechanical force they're being subject to. Put simply, the more you squeeze them, the larger the electrical signal is. Now, inside your cell phone is tiny mass at the end of a tiny fixed beam. (I'm going to stop saying tiny now; it's all tiny). Also attached to that mass are beams which have piezoelectric sensors in them. As the mass is moved by changes in acceleration, the force on each of the sensors varies. If you're moving the phone upward, the down sensor has more force on it; if you're moving it to the left, the right sensor has more force on it, and so on. By measuring the changes in electrical charge of those piezoelectric sensors and combining them (so if it sees the down sensor and the right sensor with higher signals, it knows it's moving up and to the left), the phone knows which way the phone is oriented and moving and can report that to the operating system."
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kyglp4 | Why do gas burners go from off to high to low? Wouldn't it make more sense to go from off to low to high? | Technology | explainlikeimfive | {
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"It's so that you can minimise the flame on the burner without risking having the whole thing turn off. If it was the other way around you would often try to set the gas even lower to the point that it could easily blow out. But you don't try to adjust a high flame down towards the off position, so it's more reliable (and safer).",
"They need to put out a high volume of gas in order to ignite, then the user can adjust it down to the desired output.",
"Because it needs that higher gas flow to turn on safely so that all the gas burns and doesnt build up, so when you start it, it starts on high gas flow, then you can safely turn the flame down, while still burning all the gas because it already has a flame.",
"Depends on the burner setup. My stove you have to go all the way up to ignite, then it is Light- > High- > Med- > Low- > off. I've also had stoves that go the way you've indicated. So it's a manufacturer discretion thing"
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kylscy | What is cloud hosting? | My dad has asked me to help move his business "on cloud" (whatever that means) and I'm having major trouble understanding all the terms given online! | Technology | explainlikeimfive | {
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"What this means is instead of hosting a website or data locally on a server located at your business, you instead use a cloud provider such as AWS, google cloud, or azure to host it or perform other services. Sometimes this is more expensive, it depends what you’re doing and what you already have. Billing can become really complex. Imagine something happens and a fire burns down your dad’s business and computers are destroyed. How quickly can he get everything back, including business records?"
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kyojdx | Why do some hi-tech devices with fully-drained, permanent lithium ion batteries need some battery charge before working even when you plug them in? | I've noticed this with ipads and iphones. If it's completely drained and you plug it in, you still can't turn it on for a few minutes. I don't know if the battery is part of the standard circuit powering the thing or what. | Technology | explainlikeimfive | {
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"The battery has to deliver a minimum voltage for the device to work properly. The voltage that a battery delivers decreases as its charge decreases, so if the charge is too low, the voltage will be too low."
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kyqh3d | how does Ping work? | Technology | explainlikeimfive | {
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"Imagine that you want to see how fast the post office is, so you mail your friend a letter that says \"Hey - send this back to me as soon as you get it.\" As soon as you drop it in the mailbox, you start a stopwatch. When the letter comes back, your stopwatch says it's been six days, so your ping is six days. Internet ping is exactly that, only with an electronic signal from your computer to some faraway computer and back again. For most games, 20-50 millisecond ping is good, 100 milliseconds is getting too slow for fast-reaction games like shooters or Street Fighter, and up around 300-400ms even non-reaction games can get a little annoying. The word comes from submarine sonar, where you send out a sound pulse (which, inside the sub, sounds like 'ping') and time how long it takes to reach an object and bounce back, and the time interval tells you the range.",
"The command in a command line interface, or actual ping between computers/networks? I'll explain both, since they go hand in hand Command line interface : It sends a packet (a small piece of data) that says \"reply to me\" from one host to another, and measures the time it takes to receive that reply, or even says it never received a reply after a predetermined amount of time passes. Ping between networks/hosts : Information can only be sent and received at such a high speed, and when you have routers and switches moving that information around and processing it, it all adds a little bit of latency from initially sending the information from one device to another."
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kys5nz | Why are there so many file formats for audio, video, and photos? | I know there are some formats that are for raw files, but most others are compressed. Why are there so many of those? | Technology | explainlikeimfive | {
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"[Relevant xkcd]( URL_0 ) Sometimes they serve different purposes. For example GIF and PNG are lossless formats so they are meant for graphics, while JPEG is a lossy format so it's better for things like photographs. Sometimes they're just advanced versions of previous formats, for example PNG is the successor of GIF, with better compression and quality. Sometimes they are just competing formats developed by different companies.",
"NB: lossless and lossy are terms used to describe the method the raw information is compressed. Some formats, like JPEG, actually damages the images...so you lose things like transparency, and get jagged edges on your lines From a photo perspective, raw files are determined by the camera manufacturer. Mostly because each camera company has their own way of processing image data. Keep in mind that raw files are actually just raw data tables that another program has to turn into an image. Camera companies used to saddle their devices with their own software, but now with Adobe being the industry standard, companies often just develop plugins than can be installed to make it easier to process the Data. Other formats like PNG (Portable Network Graphics) are used in graphics because it is lossless, meaning, each time it’s used/opened the information isn’t affected. So it comes in handy when working with graphics and/illustrations. It’s not great for photos since it’s colour profile is strictly RGB (red green blue) which makes it great for screens but not good enough for print; which is why TIFF (Tagged Image File Format) is used. TIFF is a lossless format that has some compression but without degradation and this is the format most print and photographers work with since the colours can be worked in both RGB (screen stuff) or CMYK (printing and paper stuff). After work is done all images and digital anything are often exported to JPEG which is a lossy format...since it’s designed to be on the web the compression puts more emphasis on size instead of quality. So to get the best JPEG you have to start with the best possible version of everything else.",
"These formats were all invented at different times in computer tech history, under different constraints. A lot of early image formats, were devised to go with a particular OS or computer hardware, and the format's colour scheme matched up with the colours that computer was capable of producing, etc. An early frontrunner as a standard was .bmp or \"bitmap\", which was supported by a wide variety of systems including Windows, Macintosh and Amiga It wasn't until the Internet started to become important, that interoperability and data compression began to matter - and, critically, intellectual property. In the early Internet, .gif and .jpeg were the two ruling image formats, and they used quite different types of image compression, and had quite different features. Like .gif could only encode 256 colours, but it could animate. .jpeg could encode millions of colours, but the compression degraded fuzzily and could make text look bad. And the patents to these formats were owned by different entities - and both of those entities required you to pay a licensing fee if you wanted to make and sell software which used these formats. And as time went by, the math and computing theory behind data compression was advancing, so people were exploiting newer techniques to get more usable info into less storage space the whole time too. It was the same with video formats. .mpeg and .avi and .mov (and RealMedia, and some others...) all came with different licensing expenses if you wanted to release software to play them. And the art and science of getting high-resolution video to compress well and look nice, well, there were a lot of approaches with quite different strengths and weaknesses. Around the early 2000s there was a big explosion of different software vendors releasing their own slightly-improved optimized codec as its own uniquely branded and licensed thing, and it became an interoperability nightmare. DivX and XviD were just 2 out of dozens of mutually incompatible and confusingly named formats out there. Various ['Codec Packs']( URL_0 ) started popping up, to try and give users an easy \"this should play most videos you ever find online\" bundle. Each of these formats had a company behind it fighting for market dominance, whereas people writing video player software for end-users, just wanted to be able to support everything without the user having to worry about it. So the end result is that we have a great big installed base out there in the world, of video and image editing software that can all read and write to a pretty big handful of well-known file formats, and a lot of those format wars are now old enough that the original patents have expired anyway. But that's the historical reason for having so many. It's just kind of the messy leftovers of a patent gold-rush."
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kysk7m | how do underwater flares (or matches) maintain a flame or light when they are surrounded by water? | Just watched Crawl (2019) and got me thinking. Edit: i should clarify, why do they not extinguish like a normal flame. | Technology | explainlikeimfive | {
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"We're used to seeing fires that get their oxygen out of the air, but that's not the only way to do it. If you heat up a material with a lot of oxygen in it, like a sulfate, a phosphate or a nitrate, it can break down and release oxygen gas. So a mixture of, say, magnesium metal and some kind of nitrate, could keep itself going underwater. The nitrate breaks down and releases oxygen, then the oxygen helps burn the magnesium.",
"Anything which can sustain combustion underwater is able to do so because the three requirements for fire, namely a fuel, and oxidizer, and adequate heat, are present. For many fires, water is a good choice to extinguish the fire because it disrupts both the oxidizer and heat production. However, it is possible to create mixtures of substances which have adequate contact between fuel and oxidizer despite the presence of water and generate enough heat to continue the combustion reaction even though much of the heat is going towards boiling water. A typical flare that works underwater will have a finely powdered metal like calcium, aluminum or magnesium mixed with an oxidizer like a sulfate or nitrate compound, all bound together with some glue-type mixture. These reactions release a lot of heat and the flare has the oxidizer and fuel in physical contact and therefore the flare can burn underwater. There are also underwater cutting torches which work through a different mechanism, namely that they release high pressure shielding gas around the oxidizer and fuel gases to prevent the water from coming in direct contact with the flame so that the flame is not extinguished. ___ Simpler: Although the fires you're used to generally consume air, you can create fires that don't need air because they use a solid mixture of fuel and oxidizer. Those fires can burn underwater if they can produce enough heat to not be extinguished by the cold water.",
"To add on to the other replies, it's a similar reason to why rockets can still fire their engines in the vacuum of space; they bring their own oxygen with them.",
"A fire needs 3 things to burn: 1. Heat 2. Fuel 3. Oxygen Normally there's plenty of oxygen just hanging out in the air, so that one is a given. If you want an underwater fire though you've got to bring your own oxygen. So underwater flares are usually a combination fuel and oxydizer in a solid stick. Give it a good shot with a friction striker and you have everything you need for a fire!"
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kyt4at | There a only a handful of viable operating systems out there (Linux, Windows, and (?). What makes it so difficult to make a fresh operating system? | Technology | explainlikeimfive | {
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"It's not. Writing your own basic OS is a fairly common computer science/engineering undergraduate assignment. But that's a purely academic OS that doesn't really do anything interesting and has zero applications. Writing a full-featured modern OS is the evolutionary tasks of hundreds of engineers working for years (potentially much more). It's not trivial so you need to have a really good reason to do it. The major consumer OS's (Apple, Linux, Windows) do almost everything that anybody wants for most applications. Specialized industrial OSs are absolutely a thing but you rarely see them outside their niche. It's like asking \"Why is it so difficult to make a new optical disk format?\" It's not, but there's a giant install base of Bluray players and they do almost everything anybody needs so you need a really compelling reason to get all those people to switch. It's a lot easier, most of the time, to just figure out how to do whatever you want to do on an OS that already exists. OS's also have many of the same core functions...once you figure out how to do that really well, where's the benefit in writing new code to do the same function over again?"
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kz3nd7 | How do video compressors work? | I've been using a video compressor under 8mb for discord videos and I've been wondering, how do they work? | Technology | explainlikeimfive | {
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"By getting rid of information that isn’t too important. There are two types of video compression, intraframe and inter frame. Intraframe works like image compression, it looks at each frame of video and tries to reduce the information it needs to store. For example if the image is of the night sky, instead of storing the very low brightness of each black pixel it can just say ‘all of this group of pixels are black’. You lose some information because they likely weren’t all exactly the same colour but it’s close enough. This loss of information is why highly compressed images or video have blocky patches of colour. Inter frame compressions is also important, storing every frame of video would take gigabytes of space for even a short HD video. Instead we start with a frame and then store what transformations need to happen to get each new frame. I.e if someone is waving then you don’t need to store the entire image every frame, just store it once and each new frame the video says to move the block of pixels corresponding to the hand by some amount. Every now and again we need a new frame but doing this can cut down the file size by an order of magnitude. Your compressor is likely doing both to the video file, increasing the space between stored frames and also compressing those frames."
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kz7g9v | why does Lithium batteries get less efficient after a while? | Technology | explainlikeimfive | {
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"This is a general property of all batteries. Batteries depend on what’s called an equilibrium or a reversible chemical reaction. In theory the reaction should be able to cycle indefinitely. In reality, every cycle causes some degradation in the geometry of the battery. In the case of a lead acid car battery, an electrode may literally break in half.",
"Batteries produce electricity via chemical reactions. Rechargeable batteries have 1 or 2 chemical reactions that are \"reversible\" meaning that if you put electricity into the battery (charge it), everything will happen perfectly in reverse. However, the chemicals inside the battery don't JUST have 1 or 2 reactions occurring. In reality, there are likely over a dozen different reactions that can occur within the battery. The manufacturer has done their best to prevent the other reactions from happening though, because these other reactions are undesirable. They are NOT reversible. Meaning once they occur, they change something inside the battery permanently. (The reversibility of a chemical reaction has a lot to do with energy transfer. If a particularly stable product is formed, it's extremely hard to break that product apart again, and if you tried, you'd ruin other components of the battery.) There are reasons why these reactions exist, of course, but that's beyond the scope of ELI5. Think of it like this. Imagine a water filter. Water can flow through one way, and it can be forced out the other way to \"clean\" the filter. But occasionally, whenever you do that, a little tear forms somewhere inside the filter or a piece of debris CAN'T be forced out of the filter. As that happens over and over again, eventually the filter is going to be less effective, right? The same thing happens with batteries. You use the, you charge them, etc. but occasionally \"side reactions\" occur that degrade the \"health\" of the battery and make it have less charge overall."
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kzbg9a | Why does it take a lot of time to move, let's say, 600GB of archives between two folders in Windows 10, but it's almost instantaneous to move the folder itself (with all those archives inside) to another? | Technology | explainlikeimfive | {
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"The way the file system works is that the windows explorer hierarchy is just pointers to the actual physical location on the drive. And moving stuff between different folders in the windows explorer hierarchy isnt moving the actual data. It only moves the actual data if you're trying to move it between two different drives. It's like you have a lot of junk in your garage and you created a filing cabinet with different folders with paper that that specifies where something is in the garage. You move a piece of paper from one folder in the filing cabinet to another folder. That's fast right?",
"Because of the way the file system is set up, moving a folder from one place to another just requires you to change the pointer telling it what folder that folder lives inside. If you're moving the contents, though, it has to do that but for every single file separately.",
"Only when on the same disc. The folder is simply relinked. So let's say you have Folder A and B and you move A into B, the filesystem is linking A as a subfolder of B. Nothing else is changed. If you move it to another Disc, you'll notice it'll take the same time as usuall as all the content is copied over.",
"Filesystems are like a huge set of library shelves. But the index to what book is on what shelf is stored in the librarian's card system. If you want all the books on, say, gardening, then they point you to the gardening section. But that might include a book on science about gardening. So they'll tell you where that book is too. But if you want to \"move\" a book so that it's in \"science\" instead of \"gardening\", permanently, then you don't have to move the book at all. All you need do is rewrite the index. That's quick, simple and needs no movement of large amounts of data (the book). It's only when you want the book in both gardening AND science (i.e. a copy) that you need to then copy the book - which is exhausting and time-consuming. And if you delete a book, you have to go to the shelves, find it, and remove it and maybe rearrange the shelf (if it was holding others up, for example). That's time-consuming too. So \"move\" is almost instantaneous. Whereas \"copy and then delete\" takes LONG in comparison. It comes up all the time in computing. It's also the difference between pointers and variables, to passing by value, and passing by reference, to DMA versus memory copying, etc. If you want me to tell you where the book on gardening is, that's easy, quick and I don't need to do hardly anything. If you want me to GET you the book, or make you a copy, that takes longer, and more effort and the computer (librarian) needs to do a lot more work. There's a reason that computing uses a \"files / folders\" analogy too. You can copy a file or folder full of files if you want, but it's quicker to just give someone the file or folder (but then it means that you won't have it any more). Note that when you cross filesystem boundaries (e.g. you want to \"move\" from one device to another), this is just like moving a book between libraries. No matter what you do, it involves physical movement, effort and time. So \"move\" between two different drives is often the same as \"copy and then delete\". It's only when everything is on the same drive (in the same library) that \"move\" can be done with just an eraser and an index card."
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kzbt1h | Why are monitors 144 hz instead of a flat 140 or 150? | Technology | explainlikeimfive | {
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"It's divisible by 24, which is commonly used for cinema. If it was 140 hz you would have some weird possibility such as 20 frames showing for 7 cycles (which wouldn't sync with cinema), or stretching some frames for more refresh cycles to make 24 frames last 140 cycles (instead of showing each frame for 6 refresh cycles). 150 would have a similar issue. 144hz was the most sensible choice because each frame can be shown for 6 refresh cycles, and it can be split in half for 3 refresh cycles for each eye if used for 3D.",
"Oh boy. 3 comments and 3 different answers. None of which are entirely accurate, but each contains some of the reasons. So long story short, 144Hz is just the perfect nexus of a lot of happy accidents. Firstly, it is divisible by 24Hz where the 120Hz standard is a factor of 30Hz. You'll generally find these two factors behind most monitor refresh rates. Sometimes you'll find oddball refresh rates, but they don't ever catch on. 24 and 30 will be the two factors you'll find as one is the traditional framerate of film and the other is the traditional framerate of television. You scale upward from there. EDIT: I just want to note that there's absolutely no other reason to use framerates divisible by 30 or 24. There's no inherent benefit from them. It's simply adhering to traditional standards. Second, 144Hz brings you under the 7ms pixel response time. 6.9ms to be a little more specific. (1000ms / 144 = 6.944...) This means you can get the full benefit of 7ms response time LCD panels. (This isn't something I'm intimately familiar with so I hope I'm explaining it properly. Just going by how it was explained to me.) Third was bandwidth limitations. I'm unable to find the original source for this at the moment so I'm going by memory. At the time that 144Hz monitors began appearing on the market the bandwidth limitations were in that same range. You couldn't really push much more information to the monitor and because of points 1 and 2, 144Hz was settled on. EDIT: Someone below put in the actual technical specs that backs me up on this: URL_0 tl;dr: The maximum refresh rate of a 1080p image at 24-bit color depth is 159Hz. 144 was picked because of the first two points because it's the nearest \"standard\" refresh rate. There's also anecdotal accounts that overclocking of displays landed on 144Hz because it is exactly 20% faster than 120Hz and was the sweet spot for overclocking. Of course there's absolutely no concrete evidence that I could find. Mainly just going by what people say worked for them.",
"Most of the answer is not really correct. Put it simple: DVI dual link max data rate is 7.92Gbps. 7.92G/1920/1080/24(bit per pixel)=159 The closest number that divisible by 24 (somewhat \"standard\" framerate) is 144",
"Better question why does my 27 inch gaming monitor at 2k 144hz cost more then the 50 inch 4k smart tv I just bought?",
"Lets do some history: it's the 90s and CRTs are everywhere. CRTs will have a noticeable flicker when using a low refresh rate. That's why they're all at least 75Hz or more. The 2000s come around and LCDs go big. LCDs are always backlit and there's no back flickering between the frames. So 60Hz was enough. Now fast forward to 2008 or so: 3D is coming back! But wait: they use shutter glasses to show one frame for one eye while they black it out for the other eye: flicker is back. And 120hz just wasn't fast enough to not see flickering (the 120 hz had to be shared across both eyes. Leading to a 60hz shutter on the glasses, which made the flickering visible again). Now comes 144hz around, 72hz for each eye and the flickering is gone. I sadly couldn't find the source, but that is what I remember reading back in 2010 or so"
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kzchox | Why is the computer mouse called a mouse? | Technology | explainlikeimfive | {
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"text": [
"It was originally called X-Y position indicator for a display system. Later it was called a mouse because it looked like a mouse. URL_1 URL_0"
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kzeqkc | Why can't PC manufacturers use GDDR5 as system memory like PS4? | Technology | explainlikeimfive | {
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"GDDR vs DDR is a matter of usage. GDDR is optimized for bandwidth, sending lots of data at once which is good for parallel processing. DDR is optimized for latency which is better for CPU tasks. The numbers are also a bit confusing because the generations don't really line up between the two. GDDR5, and 4 are based on the same tech as DDR3."
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kziho9 | How do Rancher, Docker & Kubernetes work together? | I just learned about these pieces of software while doing some research for my new home network. It makes me feel not very smart. Please - ELI5 | Technology | explainlikeimfive | {
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"Docker - creates containers in which applications can run. A container is like a lightweight Virtual Machine; rather than sharing one physical machine with multiple VM instances (which each require their own Operating System), you're sharing one single OS kernel with multiple container environments. Kubernetes - orchestrates containers. Allows you to easily manage multiple containers across multiple machines, including automating the creation/destruction of them. For example if you want to run a cluster of Docker images that automatically scales based on load, Kubernetes could do this. Rancher - adds a nice GUI on top of Kubernetes and simplifies the installation and creation of Kubernetes clusters."
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kzjmp7 | Why an RX 6800 graphics card uses 12gb VRAM when playing Warzone, but a 3070 would run the game fine with only 8gb Vram? | As the title reads. My amd RX 6800 graphics card uses 12 - 13gb of vram when playing Warzone and other games. How would a 3070 or a 3080 for that matter with only 8gb or 10gb VRAM run the game in similar or better performance? Does the VRAM not really matter? | Technology | explainlikeimfive | {
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"Most likely the game detects what size vram you have and loads everything it can into it, which would look like you need more vram but it's just basically cramming more into it because it can.. Think of it like you are planning 2 vacations you have a choice between a smaller suitcase and a larger one. The smaller one is big enough to fit one vacation with of stuff in, but you would need to repack between vacations. The bigger suitcase had enough space to fit both vacations. It's not a perfect metaphor as the vram is constantly being loaded and unloaded depending on what you do in game. More in all likelihood, when if you had 20gb of cram the game would saturate that too. While in reality the vram is so fast, you realistically only need 3 or 4 gb to never notice a difference."
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kzkj1m | How do universal remotes work | Technology | explainlikeimfive | {
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"Typically they have an IR sensor, you put it in programming mode, push that button you want on the original remote and it records the pattern of flashes. Some also have a lot of the signals for major appliances preinstalled.",
"They store the patterns for tons of devices and let the user either cycle through them or enter codes to activate them. It’ll continue using that set of patterns until programmed otherwise. I had a remote in the 90s that had an IR receiver on one and and you could program that remote either by cycling through the codes or by actually using a current remote and it’d detect the patterns. It was also voice activated which was neat when it worked."
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kzlkib | Why do old cartoons and shows have those little white and black dots pop up randomly? | Technology | explainlikeimfive | {
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"If you’re not talking about regular old dust and scratches on old film, you might be referring to those big black dots that sometimes flash at the upper right of the screen. These are called cue marks, and they’re a signal to the projectionist at the theatre that the film reel is about to end and they need to switch to another reel soon. An entire movie can’t fit on one reel of physical film; in a theatre, there’s actually two projectors in the booth and the projectionist’s job is to switch between the two seamlessly at the exact right moment. The reason we see them on video sometimes is usually because the video copy is sourced from a film reel meant for use in a theatre, which are sometimes the only available copy (a lot of older films just weren’t archived properly, and *really* old films were often printed onto a kind of film that loved to catch on fire in storage)."
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kzlurr | Can holding down the power button on your PC/laptop to switch it off actually damage it? If so, how? | Technology | explainlikeimfive | {
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"Can result in data loss, possible os/file corruption because you're forcing it to power off rather than a graceful shutdown. Files could be in the process of being written. But on the odd occasion if it's frozen, that's not really a big concern. But if you're doing it on a regular basis...shit it down properly. That's why that option is there.",
"Well, in the days of ye old Windows 95 or older, that was true. You see, the whole reason that a \"shutdown\" procedure existed (It is now safe to turn off your computer) is because just cold-stopping power flow could cause surges or damage fragile electronic parts. What changed? Well, the actual power button changed. One: To an actual button instead of a switch, and two: the function of the \"power button\" changed. It went from acting like a light switch that just breaks a circuit to being a signaller that tells your computer to start powering down itself safely and THEN power off Nowadays we call that an APCI, and it's also why you can choose options like \"sleep\" or \"restart\" from just tapping the power button (usually).",
"It can't physically damage it, but if data is in the process of being written it might be corrupted.",
"There's a simple chef analogy that works quite well. Imagine your computer is a head chef coming to the end of the work day. Assuming the restaurant closes on time he and his team has time to clean up, wash dishes, dry dishes, stack dishes back into cupboards, scrape scraps into the bin, chuck the tea towels and chucks cloths into the wash etc. Then the next day when the restaurant opens again everything is neat, clean and placed where it is supposed to be. Now imagine that instead of that the restaurant simply closed abruptly during peak hour and forced the team to go home without cleanup. The kitchen is an absolute mess, nothing is neat, nothing is orderly, things get misplaced, things might get broken. That is essentially your cpu, ram, hard drive etc.",
"Holding down the power button on a modern PC or laptop (made in the last 15-20 years) will not meaningfully damage the hardware itself. The hardware itself will work just fine next time it powers on. The data in the PC will *usually* be fine as well, however it may get damaged (corrupted) instead. There are a few reasons why, here are a few: - Writing (Saving or copying) data: When power is suddenly interrupted, the incomplete written data is unusable. It often can't be salvaged, in which case it has to be deleted. - Storing temporary data in RAM: Any data in RAM is almost immediately lost when power is removed. So, if an operation is, for whatever reason, using the RAM, on restore the data in the RAM is lost, which could result in an incomplete (and therefore corrupt) set of data depending on what was being done. In either case, only the data is damaged and not the actual PC itself. If the data wasn't important anyways, the data can simply be wiped and reset and the PC will function as though nothing happened."
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kzncbz | How did recording music change with the Beatles? | For example, what were some things that were new then that we take for granted now? | Technology | explainlikeimfive | {
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"Quality for them was a very important thing, that's one of the reason they abandoned tours and dedicated to studio recordings. Back then wasn't possible to have a good sound system in areas with huge crowds, if you see the videos you'll hear mostly screams of their fans. In studios they used the top equipments they had on time and had some practices like putting the microphones closer to the instruments, which wasn't a real thing before them. Some techniques of audio editing started with them as well, such double track vocals."
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kznua6 | Why is higher color temperature (5600k) considered cool and lower (3400k) considered warm? Previous answer explained that bluer looks like ice and yellower looks like fire which explains cool/warm, but where do the numbers come in? | I know in Kelvin is a temperature scale where 0 is absolute 0, but what relation to color temperature is the kelvin number? | Technology | explainlikeimfive | {
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"When an object is hot, it glows. Body-temperature objects glow in far-infrared light, which is how thermal cameras work. Hotter objects glow in near-infrared and even visible red light. This is why hot objects can look red. Thus the origin of \"red hot\". However, if you make things hotter still, they will glow in green and blue light as well. They then appear white, since they glow in red/green/blue all together. Hotter still, and they glow blue. However, at this point, they are usually so bright that our eyes saturate and they still appear white - the blueness is only visible through a darkening filter. This is hotter than 99.9% of the things you'll see in your life. The exact balance of blue-red depends almost exclusively on the temperature of the object. As such, we can describe this balance with a real temperature. A light meant to mimic sunlight's red-blue balance should be around 5,800k.",
"Everything emits radiation depending on its temperature (Black Body Radiation). The higher the temperature of the body, the shorter the wavelength of the emited radiation. So for \"lower\" temperatures, this means only radiation with large wavelengths is emitted. For example humans and animals emit infrared radiation that can be seen with certain cameras. If you further increase the temperature, the body starts glowing, which means that the radiation now has a wavelength that is visible. And the visible light which has the longest wavelength is red. Increasing the temperature even more shifts the color like going through a rainbow, until the wavelength is too short to be seen. However, this is not exact, so it's more of a tint than the actual color. You can see that when heating a peace of metal: it will start glowing red, then white and ultimately blueish. (Mathematically this is described by [Wien's displacement law]( URL_0 )) I also want to add something about the strange names of \"warm\" and \"cold\" light. Like you said, the color of ice and fire is a reason for this, but there are also others. Because we humans can feel infrared radiation with large wavelengths as warmth. But we don't feel ultraviolet radiation with small wavelengths. However, a body has to be a lot warmer for it to emit ultraviolet radiation than to emit infrared radiation. So a \"cooler\" body emits radiation we feel as warmth, but a \"warmer\" body emits radiation we don't feel at all."
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kzo685 | How can a chromecast keep playing video, without stuttering or buffering, if the device that is casting the video turned off and on while it was still connected to the chromecast | Technology | explainlikeimfive | {
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"All the device does is tell the chromecast what to stream. Once it does that the chromecast takes over and streams the content by itself ( until you tell it, via the device, to stream something else).",
"Think of your phone as a remote control, and the chromecast is the TV. If you take the batteries out of the remote control, it doesn't kill the TV."
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kzrwpi | Why do we have different game bugs on different computers if the game code is the same? | Why isn't it the case that all players have exactly the same bugs? For example, if two people have two different videocards, but the game code is the same (and contains the same bugs), shouldn't they behave in the same way? | Technology | explainlikeimfive | {
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"just because the game code is the same doesnt mean it works well with the hardware and software of the system running it. graphics cards often need patches to make them run better with newer games. same goes for the code of the game, generally needs to be optimized to reduce bugs with certain hardware. not all hardware or software works in the same way.",
"While the actual game code is identical, the way that the game talks to the video cards will be different. In a way, it is a bit like traveling abroad. If you go to another country that speaks the same language as yours, but has a very different culture, you'll still have the occasional misunderstanding. LIke the word \"biscuit\". People in the UK and the US both speak English. But a biscuit in the UK is something fundamentally different than a biscuit in the US. If you are from the US and ask for a biscuit, you're going to get something you definitely did not want. But, if you travel to a country with a different language than yours that you speak and understand but are maybe not exactly fluent, you'll tend to have MORE misunderstandings and they'll tend to be worse."
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kzu24g | how exactly does blocking a number stop them from not being able to message you | Technology | explainlikeimfive | {
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"For landlines, (if those still exist in your spaces. They barely do in mine), blocking a number is accomplished at the “switchboard” end of things. Basically when a call comes in from a number to a number, the call router will check a database to see if the calling number is blocked first before forwarding the call on. This probably only happens at one “node” along the call’s journey, but not sure which one. Mobile phones and messaging services likely work similarly. When you block someone, your client app will add that number/profile to a blacklist to check against when receiving a communication. It *may* also share the blacklist with the network servers/cell system, which will stop the call when it enters the system because then bandwidth isn’t wasted on sending a call that is doomed to fail. Not sure if that happens necessarily, but it would seem the logical approach"
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kzuxqy | What does it actually mean to install a software? What is the computer/OS doing that means it is installing? | Technology | explainlikeimfive | {
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"Broadly speaking it means just copying files to the locations they belong. For most Windows apps this is inside `C:\\Program Files` (or whatever it is these days), but there can be a few management steps involved as well. Putting an entry into the start menu, on the desktop (eww...), adding a file type association so that double-clicking a document/file will run your software to load it, and maybe other things like that would be appropriate. \"Installing\" software will usually accomplish these steps, and Uninstalling will delete them.",
"Funny that you ask, I'm working on creating an installer for a project right now. There are already some excellent answers here, but I'll add my own because there are some things not mentioned. An installer can first check if the program is capable of being installed on a system. Maybe your OS is too old, and then the installer will tell you that. Then, the installer can also check if any dependent programs required are installed or not, and optionally install them right away. For example, to install \"MyProgramB\" you first need to have \"MyProgramA\" installed. Then, you'll usually have to provide some kind of input in the installer. The install location, if you want the full program (complete installation) or just a couple features, maybe some additional parameters etc. Using these parameters, the installer will decide what files to copy over into your system. The installer usually registers the entry point for the program (MyProgram.exe on windows) in the start menu folder, so that when you search for MyProgram, it'll find that .exe file to start up the program. There's many, many more things that can happen during installation, for example adding entries to the registry (kind of a system wide database) or setting up a web server on your computer, but the above is the basic procedure."
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kzv2qm | What’s the difference between a MRI Scan, CT Scan, PET Scan, and X Ray? | By the way, I know what an X Ray Scan is but I don’t understand exactly how it works. | Technology | explainlikeimfive | {
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"x-ray = 2D, shoots radiation to get a 2D picture of the target area. primarily just for seeing if something is fractured/broke MRI - 3D image, used to primarily see soft tissue injuries. more detailed than a CT but takes longer CT - lots of xrays stitched together to make a 3D image. Used if patient has metal inside them or in case of emergency. quicker than an MRI and doesn’t use magnets so safe for metal implants. PET scan is different: you basically get juice that has radioactive markers in it which lets doctors see overactive and under active areas of the body which may indicate cancer or an infection",
"Xray - basic picture through the body, and mainly good at seeing dense things like bones but can be used to see changes in density in lungs for chest Xrays CT Scan - Take an xray machine, make it go in a circle so you can take hundreds from different directions, then use a computer to sort out the data into a 3D model. 3D Xray! Similar to a standard Xray its mainly good at seeing differences in density MRI - MRIs use strong magnets and RF to excite the hydrogen atoms in your body, this lets it see soft tissues and anything with a high concentration of water in it. Xrays can detect differences in density, MRIs detect differences in concentration of water so Bones look different from tendons which look different from muscles and fat. PET scan - Positron Emission Topography adds a \"tracer\" chemical to your blood which has Flourine-18 in it which decays by launching a positron instead of an electron, this positron will hit the first electron and then turn into two gamma rays shooting opposite directions and the detector can then figure out where it was. Because the tracer is moving in your blood, PET scans are good for detecting areas of high/low blood flow which can show if your organs are working well or if there's a tumor commandeering more blood than that region should have. Basically there's an assortment of different tools depending on what you want to look at. An Xray is super cheap and easy these days (there are small carts that can do them) while PET scans and MRI scans require expensive dedicated equipment but can show you things an Xray never could."
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kzz5w3 | When you empty the recycle bin on a PC, where does all that data go? | Technology | explainlikeimfive | {
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"It's basically like a hidden folder, when you empty it the location as to \"where that data lives\" on the disk is deleted. This is know as the FAT table (file allocation table). The data is still there, but the OS no longer knows where to find it, that space will eventually be overwritten.",
"Nowhere. The computer just forgets where it is. On a traditional hard disk drive, rhe data won't really be gone until the computer saves new data in the same spot, which overwrites the deleted file data. Newer solid state drives don't hold onto old data like that, which helps them run faster, but also makes it much harder to recover things deleted by mistake.",
"The joke answer: The computer landfill. Real answer, think of your hard drive as a book. There is a table of contents that's says where each file is on the disk. When you delete it from the recycle bin the entry in the table of contents is removed. The data is actually still there on the disk, but the computer no long has an entry to find it. Eventually that space on the disk will get recycled and reused.",
"first how is data stored? Well, it works like this: first there is a special information on the hard drive that says \"this is this file, it starts here, and ends here\" and then on the hard drive is that information when you have a file, and want to access it, your PC searches for for that special information, reads where the file is, and then goes there and reads it. when you want to save a file on your PC, the system checks these special informations to see with spaces are not occupied by anything. then goes there and even if there is somewhere there, it just writes over it and writes the special information thingy saying where it is. when it saves something, it only cares about that special information thing. if it's not there, then it doesn't know the file exists. & #x200B; when you put something in the recycle bin in pc, nothing really happens to anything, it is just a note that says you dont want this file, but the system wills till prevent it from being overwriten and everything, and you can retrieve it any time you want fully intact. and also you dont free-up space by moving things to recycle bin. & #x200B; when you empty the recycle bin, the system removes the special information thing for all the files that were in the recycle bin. it doesn't remove the information from the hard drive, because there is no need too. the system no longer knows these information is still on the hard drive. but you DO free up space by doing so, because if you now save some new data, it will just save it on top of the old files, overwriting them, like they are not even there. & #x200B; That means it is possible to recover these files - this is why older (very old) Windows versions had a program called \"undelete\" with would search for files without that \"special information\" on the hard drive. If they were partially overwritten, they would be corrupted (so for example after overwriting a deleted image, and recovering it, you may only get half of it back) Now Windows doesn't have this function, but there are specific programs that do the same thing. Search for deleted files on the hard drive. & #x200B; *That pretty much answers your question, but below is some interesting information if you are curious* & #x200B; If you have confidential information on the hard drive, there are programs that will go to this place and replace all the bits with 0's so it can't be recovered that eazily. This will however take MUCH more time, than just deleting the special information thing that says where the file is. However, it is still possible to recover this information, by removing the disc from the hard drive and examining it with special devices, because there will still be little magnetic energy on the surface on the hard drive, that can be retrieved (files are stored as bits, which are 1 and 0's, and magnetized part = 1, not magnetized part = 0) so even after deleting, and using programs to completely delete this information, if police gets search warrant to investigate your PC they might be able to recover it. this is NOT something averge computer user should have to worry about. For peoples still concerned, there are programs that will repeatedly overwrite the information with randomly generated data, or special algorithms, so it's basically impossible to recover by anyone. & #x200B; & #x200B; PS. I weirdly feel good explaining stuff like that so i hope you understood :) ask if you want me to explain something better",
"Imagine you have a bunch of coins that are painted so one side is white and the other side is black. You can lay the coins out in a rectangular grid and arrange them to form a simple black-and-white picture. After making the picture, you flip all the black coins over, so they all have the white side up. Where did the picture go? The picture was not just the coins, but the specific pattern of coins. When the pattern changes, the picture doesn't go anywhere, it simply ceases to exist. Data on a computer is like that. It's effectively lots of little on-off switches, but the data is in the pattern of which ones are on and which ones are off. As others have mentioned, most of the time when you tell a computer to delete a file, it doesn't actually turn all the switches off. That's because doing so takes a long time. Instead it just marks those switches as available so the next time you save a file, they can be used for the new file."
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kzzeif | What is ACID compliance in the database? | Technology | explainlikeimfive | {
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"ACID stands for: - Atomicity: it can manage a set of operations as a single \"unit\", so either everything succeeds or everything is aborted and comes back to the previous state - Consistency: basically, things are only saved if they respect all kinds of requirements defined by the database administrator - Isolation: you can have 10 people working on the same database simultaneously and the resulting state is exactly the one you expect if those 10 people worked on the database one by one - Durability.Things are actually saved in a non-volatile memory (so not just in RAM)."
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l04bs6 | Why is Accelerated Mobile Pages (AMP) bad for internet content creators? | Also, how to circumnavigate this problem? | Technology | explainlikeimfive | {
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"When you directly access the webpage of your favorite content creator, that webpage is provided by a server of their choice which gives them creative control over your visit. During that visit, they can make money by selling ad space on their website, or by selling tracking data such as the number of visitors per day, etc. An AMP link is a website hosted by Google, which copies the webpage you actually wanted to view. Part of the copy process robs the original website of any profitable user data, and instead gives it all to Google. So an AMP link is like Google taking your favorite content creator's lunch money."
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l05fjn | Why cant we copy the text from an image file through notepad then paste and save as image file and not get the original image? | Technology | explainlikeimfive | {
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"Notepad is a text editor. When you open a file that isn't text Notepad does its best to try to display it but it doesn't always work; there are many bytes that don't code to anything as far as Notepad is concerned. When you paste/save, Notepad doesn't know how to deal with all the non-text stuff and you don't get a perfect copy. If you opened the file in a binary editor that directly reads the binary code (typically as hexadecimal, 0-9/A-F), then you can do exactly what you're describing."
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l06u1j | How do advertisements and pictures get put under ice in ice rinks? | I was watching some figure skating thing, and under the ice was the name of the event, and various advertisements. And, no sign of hocky game markings. How do these get put there? I would think the designs too exact to have been made by dying the ice. and you certainly can't put the advertisements on top of the ice. But, under the ice seems so inconvienant! You would have to let the entire rink thaw, and possiably drain it to change the advetisements or the event name. I am mistified! | Technology | explainlikeimfive | {
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"Typically they are painted into the base surfaces once the white has been applied. Once that and the lines are dried (sometimes the lines are fabric - maybe silk) the side boards are put up and then the ice water application begins in layers. Here is a video of a rink conversion timelapse in florida : URL_0",
"We use vinyl mesh banner material. Graphics are printed on a roll material that goes through our wide format printer. The larger logos and graphics are sometimes made as tiled sections. They are laid in place over the first layers of ice and then more water/ice is applied over them, thus encapsulating the graphics. The mesh material holds firm in the ice due to the unique texture. The graphics can be used again and rolled up and stored after melting the ice. William, Minuteman Press, Fayetteville, NC"
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l06v04 | Why do movies only need 24 FPS, but games need a minimum of 60 FPS to be considered good? | Technology | explainlikeimfive | {
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"Also, we aren't having to interact with the movie. We can passively take in 24 fps and be happy, but when actively engaged, our eyes/brain are able to handle more (60fps is nice, but we can experience more like 240 fps in short bursts).",
"A movie just needs to have enough FPS that the individual frames appear as continuous to the eye, which is 24FPS. That's not enough for a game though: There, the player is continuously interacting with the game. This leads to a much more precise experience, so a game needs more FPS so it can deliver that.",
"24fps movies have a ton of motion blur joining one frame to the next, which makes it nearly impossible to actually see what's happening when something is moving across the screen quickly. With a game, you're often reacting to something that is moving quickly, so you need to be able to see what's going on. A lower framerate also increases the amount of delay between an input(like you or your opponent clicking the mouse), and when you see the result of that input on screen. Most monitors also don't run at a multiple of 24hz, so you get stuttering when displaying 24fps content. Movies with fast motion could look a lot better than 24fps allows, but the motion blur hides a lot of problems that would need to get fixed to make the movie look good at a higher framerate.",
"The viewing experience is totally different and I feel like we're so accustomed to movies being 24 fps we just associate it as the 'movie feel'"
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l096tb | Why do we need to click 'eject' before removing a USB stick? | Technology | explainlikeimfive | {
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"text": [
"Ultimately it's the same reason you're supposed to turn the computer off by selecting \"Shut down\" and letting it do this itself rather than just pulling out the power cable. Except it's specific to the USB stick rather than the whole computer. When you copy or delete files on a disk there's a lot of administrative work that goes into it. The space on the disk is marked as \"used\" or \"free\". The file listings is updated to add or delete your file. The file itself has metadata like the date+time it was created and modified. And of course there's the file data itself. All this data is in different positions on the disk and must be updated, one at a time, because that's how the data is organized. Interrupting the disk by unplugging it or turning the computer off in the middle of the sequence leaves the data inconsistent and will cause problems. When you \"safely\" eject the disk Windows finishes up all the work and actually removes the drive from the disk listing, ensuring there's no more modifications being done and ensuring that there's no half-finished work when the disk is removed."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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