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ahnb11 | Magnetoresistive random access memory | The wikipedia article is way over my head. So please, why it is the future and how it works. | Technology | explainlikeimfive | {
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"This isn't a very intuitive subject, but I'll give it a shot. Imagine you have two ferromagnetic plates separated by a insulator so thin that electrons can pass through it. When a source line is run through the plates, If the magnets have the same polarity (parallel) a lot of electrons can get through, but if they're the opposite (anti parallel) its more difficult to get through. In fact it's so difficult that basically none get through. This is the way binary is stored on magnetoresistive memory, so every parallel cell is a 1 and every anti parallel is a 0. To read a certain bit of memory, we run a current through a write line to whats called an NPN transistor, which is just a gate operated by electrical current that allows energy to flow from the source through the cell to the drain. To write, there are a couple of different techniques, but they all involve applying a current significant enough to produce a change in the polarity of one plate. Why is this the future? DRAM works by using capacitors to store electrons. The capacitor is either charged or discharged representing the ones or zeros. It takes time to charge and drain a capacitor whereas mram is almost instant.The charge on a capacitor doesn't last very long, so the ram has a controller that refreshes every cell 16 times a second to retain memory. MRAM is non volatile, so it requires no maintenance to retain its memory. If you unplug your computer all the things stored in the ram remain, and don't need to be rewritten when you plug it back in. MRAM also doesn't degrade over time like flash memory, theoretically it can rewritten and used until the components themselves decay. These are the reasons MRAM looks like the most promising future in memory storage technology."
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ahp2an | How does a DVD player know when you're recording the video feed and instantly turn to static? | When I was a kid in the early 2000s, I was able to hook a VHS player (VCR) up to another VCR and record a copy of the video as it played, thereby duplicating specific clips. However, if I attached a DVD player to a VCR and attempted to record, it would instantly turn to static. If you weren't recording, the video would pass through to the TV without any problem. You would only have a problem if you hit record. This happened with multiple types of DVD players and VCRs all of which were attached using either Coaxial or AV (Yellow, White, Red) cables and on a tube television. How did the DVD player know what the VCR was doing, especially considering all cables connecting the two were a one-way connection from DVD out to VCR in? ANSWERED! Thank you u/roto314 for explaining in such great detail! Here is [a YouTube video]( URL_0 ) that also explains and demonstrates what I experienced. Thanks to u/methodical713 and u/Mrl3anana for pointing out this video and channel respectively. | Technology | explainlikeimfive | {
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"This is caused by copy protection on the video signal. Unlike the copy protection on HDMI where the signal is actually encrypted, the copy protection on analog video signals has to rely on tricks. The goal is to create a signal that will look fine on a TV, but will confuse the recording circuitry in a VCR. This actually isn't limited to DVDs—some tapes had this kind of protection too. To understand how it works, first you need to know a little bit about how analog video works. A TV puts a picture on the screen by tracing it out line-by-line. It starts in the upper left corner of the screen and scans to the right. As it's scanning, it can change the brightness of the beam to whatever the picture calls for in that particular spot. When it gets to the right side of the screen, it goes back to the left and just a little bit farther down, and starts painting the next line. It keeps doing this until it hits the bottom of the screen, and then it goes back up to the top left again and starts drawing the next picture. An analog video signal changes voltage according to the brightness of the picture. A low voltage is black, and a high voltage is white, while gray is somewhere in between. So as the TV is tracing out a line, the signal is going up and down along with the brightness of the picture along that line. When it gets to the end of the line, the signal has a short pulse that's an even lower voltage than black. This short pulse tells the TV that the line is done and it's time to go to the beginning of the next one. When it gets all the way to the bottom of the picture, there's a similar, longer pulse that tells the TV that the picture is done and it's time to go back up to the top and start the next one. After this pulse, the signal doesn't start the next picture right away. It takes some time for the beam in the TV to get back up to the top left corner, so during this time it doesn't really matter what's in the signal because it won't show up on the screen while the beam is moving back up to the top. The time that goes by while waiting for the beam to get back up there is called the *vertical retrace interval*. Since the TV is putting a new picture on the screen 30 times every second, you can imagine that these signals are changing really fast. Storing a signal that's changing really fast onto tape turns out to be really hard. If the tape moves too slow, the signal starts to blur together. Imagine that you'e trying to write down a description of everything happening on the screen on a strip of paper, but you can only write so small before your handwriting blurs together. You could use more paper, but it would take more of it to describe a complete TV program. It's the same with a tape: the more tape you use, the better the picture looks. But using more tape is expensive, and the tapes would have to be bigger to store the same amount of video. In the end, they chose the speed and size of a VHS tape to have just enough for a decent picture. But it's really right at the limit: recording to the tape is always going to look a little bit worse than the original signal. When a video signal is transmitted over the air or over a long cable, sometimes the overall voltage of the signal is increased or decreased. For example, if you're far away from the transmitter, you might receive a weak signal. Or maybe there's a signal booster on your cable wiring and you get a really strong signal. A TV doesn't care too much about these differences in signal level—you might see a brighter or dimmer picture, but your eyes are good at adapting. A VCR, on the other hand, needs to make the best use of the limited tape. If the signal is weak, the pictue will look really bad when it's played back since the tape loses a lot of the small details. If the signal is too strong, it will actually interfere with the other signals nearby on the tape. So the VCR really needs to make sure the signals are in the right voltage range before recording them. It uses a circuit called an *automatic gain control* to do this. It's basically listening to the signal and turning the volume knob up and down to keep it in the right range to get the best picture on the tape. Okay, now we have all of the pieces to understand how the copy protection works. We know that the video signal changes voltage over time to represent the brightness in the picture. We know that there's part of the signal that doesn't actually show up on the screen (the vertical retrace interval). We know that a TV doesn't really care about the overall signal level, but a VCR does, so the VCR has an automatic gain control circuit that the TV doesn't. What the copy protection does is it inserts a bunch of *really big* peaks into the video signal during the vertical retrace interval, much much brighter than white would be in the picture. The TV doesn't care about this, since it's the part of the signal you don't see. But the VCR says, woah, this is a really strong signal, I need to turn it way down! Of course that makes it turn down the whole rest of the picture too! And if it turns it down far enough, now it can't reliably detect the pulses that tell it when to start new lines and pictures anymore, so you just end up with random bits of picture on random bits of the screen. Sometimes the copy protection also changes how big the pulses are, slowly raising and lowering them. So sometimes the recorded picture looks okay, sometimes it just looks a little dim, and sometimes it turns into crazy static, depending on how big the pulses are at the moment and how much the VCR is turning down the signal to compensate. Older VCRs usually always had the automatic gain circuit engaged, which meant that you'd get a bad picture or static from a DVD player plugged into the inputs on a VCR even if you weren't recording. This was really frustrating for people with older TVs that didn't have composite (yellow/red/white) inputs. Most VCRs could connect over the coax and you'd tune your TV to channel 3 or 4, but not very many DVD players did this—they only had composite outputs. People tried to work around this by connecting their DVD player to the composite inputs on their VCR, which would then connect to their TV with the coax. To allow this on later VCRs, the automatic gain circuit was only enabled when you actually hit record, so you could watch the DVD when piped through the VCR, but still couldn't make a copy. *Very* old VCRs and professional models didn't have the automatic gain circuit (or allow it to be overridden with a knob). These models aren't affected by this kind of copy protection. There's a ton of great material out there on YouTube and Wikipedia about how analog video works, including a lot of detail I left out (for example, how color is added to the signal). If you want to read more about this type of copy protection, it's often referred to as \"MacroVision\", named after the company that developed it.",
"There is a channel called \"Technology Connections\" that explain a lot of this kind of stuff, in a audio-visual format, if you would want to see that as well."
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ahpk90 | Why haven’t we started using graphene on everything (batteries, computer parts, clothing, etc)? What makes it so difficult to work with? | Technology | explainlikeimfive | {
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"I am not an expert, but from what I know there's 2 main reasons: 1. It's still quite difficult to mass produce graphene to an amount where companies can incorporate it into there products. 2. As with a lot of nanotechnology, we are still learning about them. The truth is that while they may be useful for a lot of things, we still don't know much about the negatives. It's hard to really measure for example what the environmental impact of graphene might be, because there isn't much of it around in any environment yet, and due to it being nano-sized it's hard to track it once it has been exposed to the environment."
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ahr342 | Why do so many oven windows have tiny dots all over them? | Technology | explainlikeimfive | {
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"the tinting is there supposedly to reflect thermal energy back into the oven that would otherwise escape, making ovens more efficient. So otherwise they'd lose a lot of thermal energy and work harder to compensate, requiring more energy.",
"If you're talking about regular ovens, others will answer better. If you're referring to Microwave ovens, [\"The oven door usually has a window for easy viewing, with a layer of conductive mesh some distance from the outer panel to maintain the shielding. Because the size of the perforations in the mesh is much less than the microwaves' wavelength (12.2 cm for the usual 2.45 GHz), microwave radiation cannot pass through the door, while visible light (with its much shorter wavelength) can.\" ]( URL_0 )"
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ahyn0c | Why do graphics in older movies look so shoddy years later, when there was a point the graphics seemed realistic? | Technology | explainlikeimfive | {
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"I think you'd be surprised at how much graphics are still improving. This is one of the reasons that a lot of films will use practical effects instead of cgi (they actually blow up a car instead of making it in a computer) because you can never get more realistic than just actually doing it and that makes your movie's effects last better. Jurassic Park still looks great even though it's really old because it's always photo-realistic when it's an actual photo. I remember when they redid the graphics for Halo 2 and thinking \"holy crap this looks like real people\" but the other day I played it again and it was not nearly as realistic as I remember. I think we kind of readjust to be impressed by whatever the current \"best\" is but that is a moving target and how we perceive the quality will still change over time.",
"Your brain fills in a ton of the gaps in your perception. That is to say, when Gran Turismo 2 came out and to me it looked incredibly real to me because of my experience with video games graphics up until that point. What looks ‘real’ is completely, totally subjective. But if doesn’t feel that way to us. I think it has to do with why your brain expects to see and how willing it is to suspend disbelief. In order to play the first Gran Turismo I had to suspend a lot of disbelief in order to perceive what I saw on screen as “cars”. When the graphics improved in GT2, my brain had learned to fill in the gaps of the graphics and now it didn’t need to suspend AS MUCH disbelief as before. So, it feels more “real”. Perhaps what seems “real” to us is actually just “more real than before”.",
"I'm no expert in this, but here's my take. There are 3 factors that come into play: 1. Relative quality - which everyone had already mentioned here that graphics only look bad after you compare them to better ones. 2. Suspension of belief - in a good movie, you're trying to enjoy yourself so your brain will fill in the gaps to make sure you do. Most older movies that we remember fondly were good movies that immersed us and so we had a vested interest in enjoying it. So I think subconsciously we can ignore bad graphics when the rest of it is really good (like the matrix). 3. Novelty - even if today older graphics look outdated, when they came out they were probably groundbreaking. And like in the first point, they looked far better in comparison to what came out before. The best CGI is when you don't even know CGI was used. If there's any point where you can tell that CGI was used, it'll get better in the future and this will look crappy then.",
"They never looked realistic. They just looked the best anyone had seen at the time, and people were willing to suspend their belief for the sake of it. It's just like how 8 bit games at the time were thought to be amazing, but compared to AAA titles today like Skyrim or whatever, they look trash.",
"Stuff look like shit back then, there was just no other option. So we created everything on a curve. I think that was one of the reasons why science fiction wasn't more popular to the mainstream, because some mainstream people couldn't get over the poor special effects.",
"Because \"realistic\" means close to real. So whatever is the best graphically at the time is considered realistic. As graphics improve only the best are considered to be realistic and the others are no longer considered to be realistic. The graphics remain unchanged, the world remains unchanged it it only our perception of and understanding that changes."
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ahyq3n | how can an online site like MyMathLab know when during a quiz, I am opening a different browser to cheat ? | Technology | explainlikeimfive | {
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"There are commands in various coding languages (in JS I think they're called listeners) that, as long as the code is running are constantly waiting for you to take a certain action before they activate their underlying code. These actions include things like clicking, scrolling, mouse-overs, opening/switching tabs, etc. So when you change the tab, your browser tells the javascript, which then runs the section of code that tells the browser to do something like stop you from answering more questions.",
"There’s a javascript listener which is called UnFocus, so when the focus is taken to another tab, they record this!",
"The computer has a bunch of people (programs) standing in a line, in order of priority. MyMathLab wants to always be at the front of that line. When you click out to another program, it tells that program to come stand at the front of the line. MyMathLab, because it's code is running on your machine, can see that you've put another program in front of it in priority. It assumes that if you put another program in front of it, you're cheating on it.",
"Prof here. Considered an online / take home test for my grad students. They quite honestly said that many people just have a smartphone open to effectively make it an 'open book' quiz. Worst, if it is a MC quiz, the class gets on a group chat and shares the answers with each other.",
"I'd never trust MyMathLab for that kind of information. If you want to actually verify things use a remote proctoring software.",
"It can't. All it can tell is that MyMathLab wasn't in focus for some length of time. However, there are many legitimate reasons why the MyMathLab tab might not be in focus. And not all of them are controllable by the user. You can't make the assumption that just because MyMathLab wasn't in focus that the student was cheating, or that they even intended for the MyMathLab tab to lose focus."
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ahz37f | Where do files go when uploaded online? | Just wondering how large the database is, considering each person's files in the internet. | Technology | explainlikeimfive | {
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"They go onto hard drives store inside servers in a data center somewhere. The database is indeed huge but it is spread out across many, many computers and usually many physical locations.",
"First, files aren't \"in the Internet\" and there's not one big database. The Internet is a conglomeration of many, *many* individual networks (hence the \"inter-\" part). When you upload a file it's going to the portion of the Internet that's managed by the service you're using. So when you upload a file to Google Drive it's going to a network managed by Google. When you upload something to Microsoft OneDrive it's going to a network managed by Microsoft. And so on and so forth. When you upload a file there are usually several components at play: network, storage, database, and application server. The *network* is what allows the machines to communicate to each other and to other machines on the Internet. Storing files is a database is not very efficient, so for *storage* each service usually has a file system that's distributed across many, many hard drives. Each file in that filesystem gets a unique identifier, and that unique ID is stored in a *database*. Then when you request the file, the application running on a *server*, looks up the ID in the database, then, based on that ID, it knows where to find the file in the storage system to deliver to you. (It's actually *way* more complex than that, but, hey, this is ELI5.) These days, a lot of this is complicated by the fact that cloud service providers like Amazon Web Services (AWS) or Microsoft Azure *lease* out networks and storage and databases and servers to other vendors. So, for example, Dropbox might lease networks and storage and databases and servers from AWS. AWS owns and maintains the hardware, but Dropbox builds their service on top of that hardware that they have leased. Dropbox doesn't actually do that anymore; they have their own environments. But in the past they did use AWS. (And, like above, because most of those leased environments are virtual hardware, not actually physical hardware, it's actually *way* more complex than that, but, hey, this is ELI5.)"
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ahz5qm | How does torrenting work and how is it different from a normal download? | Technology | explainlikeimfive | {
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"The idea of the BitTorrent protocol is that the person who originally shared the file is not the only person who can provide parts of the file to others. Instead, anyone with part of a file can share it to others who want to download it, thus allowing the download rate of all active clients to exceed the upload rate of the client. A file or collection of files will be divided into a series of parts, and once a client has downloaded and verified any parts, they can share those parts with others.",
"The other explanations are correct, but I will add another reason as to why it fills a different role from regular downloading. Normally, if a file is up for public download, all the data is coming from a single place. This means two relevant things, one good one (mostly) bad. One factor is bandwidth. If a lot of people are downloading a large file for you, you need to host it somewhere and it will cost money. Bandwidth, how much data is uploaded and downloaded, always costs money. It's what you pay for when you pay for you internet access. Now if a single file has even a hundred downloads, that is many times more bandwidth than any individual would use, and thus many times more expensive. And it gets worse if it is 1000 downloads, or 10,000. Torrenting means that if you put a file up for download, you don't have to pay for the bandwidth for every person who downloads it, because every person who does, then contributes a bit of their bandwidth to every one else. For most people, this won't make a dent on the bandwidth they already pay for, thus this form of hosting is basically free. This makes it highly economical. The other thing this means is because the files is not coming from a single place, it's hard to track and nearly impossible to stop. If a person offers an illegal file for download on a website, the government can eventually find and shut them down usually. If the file is coming from 1000 places at once, even if they shut one down, that leaves 999 and every time the file is downloaded, that means 1 extra place it's coming from, so that isn't even going to make a difference. This is why torrenting used to have a particularly bad reputation and sometimes still does. It's much easier to download illegal stuff with little fear of being caught or punished. These days is is being used quite a bit for legal means as well as illegal.",
"Torrenting you are downloading a file from various other people who are choosing to have the file shared between the computers. While downloading is just getting the file from a single source.",
"I'm gonna go a little more towards \"5\" just for clarification. Let's say you have a 10 gallon bucket you want to fill with water, and you have two options for doing that. The first option (traditional downloading) is to fill it with your garden hose which flows at 1 gallon per minute, so it will take 10 minutes to fill. The second option (BitTorrent) is to have ten of your neighbors fill it with their garden hoses, which all flow at 1 gallon per minute, at the same time, so it only takes one minute to fill.",
"Let’s say you want to read a 200 page book such as Moby Dick. Your local library has a copy, so you could just get in your car, drive there, loan out the book, drive home, and start reading it. With BitTorrent, you discover that your 10 nearest neighbors each have 20 pages of the book, so you call a meeting and have them all bring their pages for you. Now you didn’t have to leave your house, and you got the same book faster and without the hassle because all your neighbors shared their chunk of the book with you."
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ahzbhj | why, at airport security screenings, do electronics need to be put in a separate tray? Can't scanners see through a bag/luggage? | Technology | explainlikeimfive | {
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"Large batteries and metal bodies of your laptop/tablets block x-rays, making it hard/impossible to see other things in the bag.",
"I recall there was a short time after 9/11 when TSA rules required you to turn on your laptop to prove it was a real working device. So obviously that led to a \"laptops separate\" rule. Even when TSA stopped that particular requirement, they kept the \"laptops separate\" rules, probably for the reasons mentioned elsewhere in this thread (i.e., better scanner visibility, security theater).",
"I am a manager for the TSA equivalent in another country. I can shed some light on this for you. The main reason they make you put your laptop or any other large electronic device (cpap machines, gaming consoles, etc) into a separate bin is because of the way the X ray machines work. They take a top down and side on image of your bag. The screening officers are trained to look for IED components by doing things like tracing wires to their source or finding timers attached to organic masses. So if you have a laptop with a book or a sandwich sitting next to it in your bag it can potentially look suspicious. The other reason someone already mentioned here is X ray shielding. It is quite common for people to try and hide drugs etc behind dense metal objects like a battery or hard drive. That is also why you are sometimes required to turn on your device to prove it works.",
"They can, but when you have a lot of wires and circuitry all densely packed together things can be hard to see. Remember that the scanner only shows a two-dimensional image of a three-dimensional bag. So, they have you pull out the electronics and lay them in a single layer in one of the bins so they are easier to see on the scan.",
"Several reasons. 1. Batteries are so dense that they blow out the contrast in the images. Imagine you're in an unlit room with a window to a bright scene outside. If you try to take a picture of the scene outside, most of the room will come out dim. Try to take a picture of the furniture in the room, and the scene outside will be washed out. The same thing happens when they X-ray your bag. They can see pretty well inside your luggage but if there's a battery in there -- especially if it takes up a big chunk of the image -- they won't see much else as the system adjusts the exposure. And they really do want to see the details of the battery, too. Yes, there are ways to address this without making me people use separate bins, some intersection of improved technology and better training, both of which cost money. 2. There have long been suggestions terrorists intend to smuggle explosives onto an airplane by shaping the explosives to fit in a laptop battery compartment. So they're going to get extra scrutiny. 3. It's still a lot of security theater. Somebody says We should scan laptops separately, and everybody says Ooh yeah, that's clever. Nobody wants to be the one suggesting it's unnecessary because What If? 4. Horseshit VIP treatment. Get Global Entry or PreCheck or whatever and you can often leave your shoes on and your laptop in your bag. Like terrorists can't exploit that? But the TSA and airports and airlines love having this two tier system. It's literally in their financial interest to make it a hassle to get through security and on to a plane unless you pony up for business class or get their credit card or pay the Feds for the privilege.",
"Security theater. It doesn't make it any easier to spot a bomb, but it makes people feel like something is being done. Since the explosion of TSA regulation following 9/11, more terrorist attacks have been stopped on the plane than in the airport, because vigilant civilians see something off. The logic of making you remove large electronics is that if you put your bag through and they still see large electronics you might be hiding something. Unfortunately, most TSA employees wouldn't be able to tell the difference between a MacBook and a bomb made to look like a MacBook, so it doesn't matter. In the end, it just makes people feel like they're safer.",
"Lots of incorrect answers here. Laptops have a certain CT scan profile (e.g. small or no organic profile) and when you put other objects on top of a laptop, that profile becomes mixed and you can't determine if it's the laptop that has organic material or the object on top.",
"I recently flew from Amsterdam airport & they told me I didn't need to remove my laptop, etc from my ruck sack. Every other airport has me remove my laptop. Just finished 4 week work trip & my rucksack was packed full of wires, laptop, electronics and random garbage. They didn't even look inside. Do they have more advanced scanners or is the whole thing a waste of time in the first place?",
"Almost every policy at the airport security is to make you feel like it's more secure than it actually is",
"it's because the authoritarian police state the USA is slipping into requires you to do any mundane tasks you're told immediately otherwise you're a terrorist"
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ahzja7 | How do people making subtitles for series online can configure it to work with all different mp4 files available? | Technology | explainlikeimfive | {
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"They don't make it work with any mp4 file. Subtitles for downloaded movies are essentially huge files with timestamps and text. The video player doesn't care what file it plays, it will print text at given timestamps. That is why you usually can't use subtitle for release XYZ if you watch ABC release. It is also why you can get silly things like a swedish politican saying he will bulld the galaxys best sand castle URL_0",
"Because subtitles that aren't hardcoded into the movie are processed parallel to the movie and therefore they do not depend on the format of the movie. If the Subs are included into the Container, the Container needs to be able to contain Subs.",
"Subtitle files only specify when a specific line should appear on screen. As long as the video file isn't stretched in time (and there's no reason for it to be), the subtitles will fit. However, there are instances where the video would be cut at the beginning (e.g. someone would remove the production company logo, or a few seconds of blackness), and then the subtitles will be \"offset\" in time. That's why most video players let you shift the subtitles back and forward in time for a perfect sync.",
"Subtitle files are simply text files with time stamps. The video player reads the text files, and puts the text where it needs to be."
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"https://tv.bt.com/tv/tv-news/the-funniest-ever-tv-subtitles-blooper-politicians-talk-sandcastles-and-dinosaurs-11364034525370"
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[],
[],
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|
ai2b3j | Why do Hard Drives need to be defragmented? | Technology | explainlikeimfive | {
"a_id": [
"eekewin",
"eekri9c"
],
"text": [
"If you never deleted anything from a hard drive you wouldn't have to defragment it. But, when you delete something, you leave a hole. Later, when you write a new file it might not be the same size as the hole that was left. So, part of the file is written to the original hole, then the other part is written to the next empty spot on the disk. The file is now fragmented. When the computer wants to read that file it has to pull it from two or more spots on the disk instead of one contiguous spot. This slows things down. Defragmenting is moving things around so that all files are in a single, contiguous piece.",
"These days, they don't, really. Modern filesystems like EXTFS, XFS, HFS+ (and a dozen other acronyms) don't need to be defragmented except in extreme cases, because they will avoid file fragmentation in the first place and intelligently re-place files as needed. NTFS can go without defragmentation for a decent length of time but will eventually become a problem. FAT32 has virtually no way to prevent it. There's a rant here about Microsoft and decades of unpaid technical debt, but I'll spare you."
],
"score": [
10,
4
],
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|
ai3qek | Streaming services subscriptions | Technology | explainlikeimfive | {
"a_id": [
"eekttyh",
"eeku3jj"
],
"text": [
"There's no universal guidelines for prices. You can charge for anything as long as people buy it. Cable has advertisements *AND* a buy-in because they can. People want to watch those channels enough that they are willing to endure both. Streaming services began to be popular by undercutting those prices.",
"Companies like Comcast and DirecTV don't actually own the networks. They, too, receive a discount for bundling their services in certain packages. They then pass that on to you. Networks make their money through advertisements placed in time slots during certain programming. Some companies even sponsor certain programming to ensure their products are advertised during certain times (Ford for American Idol)."
],
"score": [
7,
4
],
"text_urls": [
[],
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} | [
"url"
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"url"
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|
ai7zj8 | If a programming IDE can identify that my code has errors, why can't it identify the error itself (or explain the error in layman terms)? | Technology | explainlikeimfive | {
"a_id": [
"eelsl5t"
],
"text": [
"It is my understanding that the IDE only tells you what it can't read and why. The system can't guess what your code is supposed to do because computers are so literal. It takes the information it has and gives you a corresponding code or bit of text to point you in the \"right\" direction. I am still a junior in the coding world but I have come to learn that not all IDEs are equal. Some are more helpful than others according to some of my teachers and my boss. EDIT: a word"
],
"score": [
3
],
"text_urls": [
[]
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} | [
"url"
] | [
"url"
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|
aibnee | Whatever happened to the FCC law banning volume increases during television ads? | Technology | explainlikeimfive | {
"a_id": [
"eemi3uf"
],
"text": [
"It’s in effect. It’s called the CALM act. Cable/sat companies and networks all do comply as well. But advertisers continue to find ways to manipulate the system and other shitty things. It’s even written specifically into every single carriage agreement between cable/sat companies and networks in their contracts that the network must comply with the CALM act"
],
"score": [
3
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"text_urls": [
[]
]
} | [
"url"
] | [
"url"
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|
aidib0 | Is there a good, logical, or historical reason why some password setup fields severely limit the field length or disallow particular characters? | Technology | explainlikeimfive | {
"a_id": [
"eemwutc",
"eemxa5w"
],
"text": [
"In some cases there might be issues with text encoding disallowing particularly funky characters like ø, ⋄, ¯, or η, but mostly it is either bad code, or them 'trying' to help by enforcing things like symbols and numbers, which are [not a good idea.]( URL_0 )",
"Oftentimes it's because the pretty website that you're using has to interact with some ancient mainframe system on the backend. The code was originally written in the 1980's and can't be overhauled without breaking everything. Back then memory space was a serious concern and storing more than 8 characters would actually have been a problem. Plus, they didn't have modern security or coding practices so they don't allow the full set of characters. There's no good reason for a modern system to have any sort of limitation."
],
"score": [
5,
3
],
"text_urls": [
[
"https://xkcd.com/936/"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
aihtrw | How is the news anchor always making eye contact with viewer, no matter which angle we sit? | Technology | explainlikeimfive | {
"a_id": [
"eentyii"
],
"text": [
"It’s a 2D image, so regardless of where you sit you’ll always have the same perspective on the newscaster."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
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] | [
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|
aijebs | How is the “feels like” temperature determined on the weather channel app ? | Technology | explainlikeimfive | {
"a_id": [
"eeo7kb0",
"eeo7zuh",
"eeo7c61"
],
"text": [
"There are several different formulas depending on what information is used. But generally it's some combination of temperature, humidity, air pressure and wind velocity.",
"They call the local meteorologist and simply ask him. \"How's it feel!\" Sometimes the simplest answer is the right one.",
"I’m not sure about this, But I think it has to do with calculating humidity and wind chill and such, don’t quote me on that though"
],
"score": [
11,
5,
3
],
"text_urls": [
[],
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} | [
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|
aik2vq | How do pregnancy test kits work. | Technology | explainlikeimfive | {
"a_id": [
"eeod9n9"
],
"text": [
"They test for one particular hormone in the urine that the body produces in large amounts during pregnancy: HCG."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
aik85r | What is the difference between an MRI, a CT, and a PET scan? | Technology | explainlikeimfive | {
"a_id": [
"eeoe88u"
],
"text": [
"All three are ways of diagnosing diseases within the body. We've covered them like this in training, but I'm just a therapist and obviously don't work with these things.. The MRI is based on powerful magnetic fields and radio frequency pulses. Imagine if you will your body which is mostly made up of water molecules, as we all know. These molecules consist of hydrogen and oxygen atoms. In the middle of each hydrogen atom you've got the proton. They work like tiny magnets and are sensitive to magnetic fields. You lie down under the magnet scanners and all of your protons just naturally line up the same way, just like small magnetic particles do when they are under influence of a stronger magnetic pull. What the radio waves do then is that they knock those protons out of their just achieved alignment by causing a temporary magnetic disturbance. As soon as the radio waves are turned off, your protons realign. That in turn sends out radio signals which will be picked dup by the scanner. Thus, MRIs can provide you with extremely detailed pictures of basically every structure in your body. Differences between normal tissue and abnormal, like cancer, is often clearer on MRI. It is bloody loud, though.. From the images I've seen I think MRIs are better for soft tissue and CTs better for bones, even though they both portray each of these. The CT scan uses x-rays, but on a higher level than your normal xray. Your body or just parts of it go into this sort of doughnut shaped machine. It's relatively silent while you get scanned. Unlike the normal xray, the CT scans different layers all at once. The rays basically cut your body into very thin layers and take lots of pictures while scanning, so they can spot densities and tissues inside a solid organ. The images compared to the MRI, especially when it comes to tissue, are not always as clear though The PET scan uses a certain so called tracer that is swallowed, inhaled, or injected to your bloodstream. These tracers move through your body or just parts of it, depending on what is getting checked. Some organs or tissues absorb the tracer. Like for example cancer cells which thrive on sugar, which is why some tracers are liquids with glucose in them. These organs basically light up on the screen. Every organ and tissue usually absorbs a bit of the tracer in any case, but where the intensity is the highest, doctors can see if there actually is a problem or. Disease or not judging by the amount absorbed."
],
"score": [
11
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[]
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} | [
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|
ain9jg | How do soccer channels add those editing effects on players and on the ball so fast (between the halves) ? Isn't it a complicated process that takes time and rendering? | Like when they add a line that follows a certain player or a line that follows the ball. | Technology | explainlikeimfive | {
"a_id": [
"eep04t4"
],
"text": [
"These days rendering is pretty much real-time for those, so it's not an issue. It is complicated, but a modern software is so advanced, that is doesn't have a problem to track 1 ball and 25 (including referees) people on the field."
],
"score": [
6
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"text_urls": [
[]
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} | [
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aiokkl | Why do laptops/pc's get hot? And will we ever have technology that stays cool under load? | Technology | explainlikeimfive | {
"a_id": [
"eep9e1v",
"eepa307"
],
"text": [
"Every conductor has resistance, which means that electrical energy passing through it loses efficiency and is converted to heat. When computers are under load, more electricity is passing through its conductors, leading to more heat. There are compounds called superconductors, which have no resistance and produce no heat when electricity passes through. Unfortunately, most superconductors only work as super conductors under extremely cold temperatures, which makes them unpractical for regular use. Room temperature superconductors are an area of research which could lead to developing computers which produce no heat under load.",
"Imagine working out. When you work out, your entire body heats up and after a time you need to take rest or cool off by drinking water or fluids. Imagine a processor. It computes, i.e. it does millions of calculations per second. For each calculation, a specific part of the processor conducts electricity. This conduction is not 100 % efficient. This generates heat. In the really old PCs, the number of calculations is very less. That leads to the generation of lesser heat than modern processors. To remove the heat, you need to attach a heat sink. This sink basically removes heat from the processor, takes the heat away from it and then dissipates it through fans placed in the PC. The more denser the fluid used for this purpose, the better is the dissipation. As an example, water performs the process better than air because water can absorb heat better than air. That is the reason why gaming PCs have liquid cooling. But a basic necessity for the fluid is not to damage the processor by corroding it. Now as we make processors smaller and more capable, the heat increases. In the future, the main problem shall be the removal of heat rather than the processor speed for this very reason. Fin."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
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} | [
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] | [
"url"
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|
aiq9gq | What do music compressors do? | Technology | explainlikeimfive | {
"a_id": [
"eepnx9v",
"eeq7p4y"
],
"text": [
"Automatically lowers the volume of the loudest parts of audio, which allows you to raise the volume of all of it, making a more consistent level. Edit: [This video]( URL_0 ) explains it pretty simply.",
"They reduce the range between the loudest & quietest parts of an audio signal - lowering the loud stuff so it's closer in level to the quiet stuff. It helps a lot to understand what the typical controls on a compressor are - Threshold, Ratio, Attack and Release are the most common controls. **Threshold** determines at what level the compressor will start working. If a signal only ever reaches -10 decibels (dB) and the threshold is -9dB, the compressor won't be doing anything. Once the level goes past -9dB, the compressor will kick in and start reducing the signal. **Ratio** determines how much the signal is reduced once it goes past the threshold that's set. If a signal goes 4dB over a threshold and the ratio is 2:1, the signal will be lowered by 2dB. A ratio of 1:1 doesn't affect the signal at all, whereas 15:1 would be considered a high ratio that would compress the signal a lot. **Attack** determines how quickly the compressor starts reducing the signal once the threshold is reached, and **Release** determines how quickly the compressor stops reducing once the signal is below the threshold. Here's an article if you want to read more: URL_0"
],
"score": [
8,
5
],
"text_urls": [
[
"https://youtu.be/543y5bzih1o"
],
[
"https://www.uaudio.com/blog/audio-compression-basics/"
]
]
} | [
"url"
] | [
"url"
] |
|
aiqxdt | What can the NSA see? | Technology | explainlikeimfive | {
"a_id": [
"eepvswi",
"eepunjd"
],
"text": [
"Who you talked to, when you talked to them and for how long, if you believe Edward Snowden. Nothing if you believe the Obama administration. According to Snowden, the NSA is hoovering up as much data as it can and storing it in a giant datacenter in Fort Meade, MD. I used to do work for the FBI concerning the discovery and location of child pornographers. The problem is, how can you sift the noise from the signal? Well in 2004, we were using a system that would hash the file you were downloading over P2P (data given to us by your ISP) that would then get fed in to a database. If that file matched the hash of a known child pornography file, we would flag that IP for further investigation. My job was simple, generate as many hashes as humanly possible. The problem with this? I could've inserted ANY hash I wanted, let's say for example a Hootie and the Blowfish MP3, or a PDF copy of 1984. Anything the government deems as criminal activity. The tool is only as good as what you use it for. That was 15 years ago, I can't imagine technology hasn't gotten exponentially better since then, using AI and machine learning instead of just basic hashing power. & #x200B; I think Snowden said it best, if he's not lying about what he did, it turley can be turnkey tyranny. Just like the Jews in 1930s Germany putting down 'Juden' on their census forms. You don't know what evil purposes the government can do with data until they do it. See: IBM And The Holocaust by Edwin Black. Amazing book.",
"Well, it's anything that they really want bad enough. If you're an American in the US who doesn't use the Internet, they can't see much of your stuff, due to jurisdictional limits. If you start to collaborate with known terrorists, they, and their FBI buddies, can do amazingly difficult things to get all you data. So, don't be a terrorist. (Generally good advice) Their biggest problem is finding the tiny fraction of good stuff in all the stuff they collect. Even on the Internet, the best strategy is to not be someone they want to know more about. So, don't be a terrorist. (...)"
],
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10,
5
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|
aiu6ed | why did 3d printing take so long to get were it is now? The hardwear and softwear seem simpler than some in consumer tech from the 2010's | *where | Technology | explainlikeimfive | {
"a_id": [
"eeqos0j"
],
"text": [
"For basic printers, both hardware and software are basically straight out of the 80s (at least on the printer side). That's because some critical idea was patented back in the 80s, and the owner never did much with it. The patent recently expired, allowing multiple people to take it and make it commercially viable. Not sure how much it would have affected things, but the slicer software (the program that turns a 3D model into instructions for the printer) actually has to be pretty damn smart to do its job effectively. That's the one part of the whole process that may not have even been possible until relatively recently. I remember writing .gcode files (the kind of files that 3d printers read) by hand for an old early 90s CNC mill, and it was painfully slow for even the simplest parts."
],
"score": [
3
],
"text_urls": [
[]
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} | [
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aivyji | Why does foreign television look so much different than US broadcasts? | I'm American and my only exposure to foreign media is new clips and Top Gear. Why does it look so "wierd" to me? It looks like a soap opera. I've heard maybe it's that foreign media is recorded at 25fps and my tv/phone is made for 24/30/48/60? Thanks in advance! | Technology | explainlikeimfive | {
"a_id": [
"eer55qz",
"eeqvww2"
],
"text": [
"It's a side effect of motion interpolation. It's called [The Soap Opera Effect ]( URL_0 ).",
"That and many other factors. Lighting, color grading etc. Also, i remember back in the day when TV was still analog, there’s a certain kind of feel to each channel."
],
"score": [
3,
3
],
"text_urls": [
[
"https://en.m.wikipedia.org/wiki/Motion_interpolation"
],
[]
]
} | [
"url"
] | [
"url"
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aiwhw7 | How does switching to electronic alternatives (for example E-cars) help environment? | I have come across many articles lately which said that electronic cars and vehicles are future because they help reduce emissions. But I always thought, how is that possible. Most of the countries still fulfil their electricity demands by generating electricity in thermal power plants, which also releases a lot of hazardous gases into the environment. Not only this, countries which use nuclear energy as their primary source, have to deal with nuclear waste, which again, is extremely hazardous if not handled with care. Another example of this is switching to computers. Human resource development ministry of India recently announced that most of entrance exams will now be online. Many environmentalists hailed this move saying it will save a lot of paper which, in turn, will save a lot trees from being cut. But maintenance of computer itself is not a completely environment friendly task. Lets say someday, its monitor is needed to be replaced. Now, the spoilt monitor is an electronic garbage and has potential to cause a lot of damage to environment if not managed properly. And just like 70-80% countries on this planet, India is terrible when it comes to e-waste management. Also, not to forget the electricity it uses in its lifetime which is again primarily coming from a pollution-causing thermal power plant. So, basically what I mean to say is, we are trying to conserve one thing which is in front of us, but deteriorating the other which is not necessarily in front of us. | Technology | explainlikeimfive | {
"a_id": [
"eer0n1k",
"eer1kxx",
"eer2dnk"
],
"text": [
"Simply put, studies have shown that so long as an EV is driven for a certain amount of time, (\\~10 years IIRC) the emissions related to its manufacturing and continued use are less than that of a vehicle with an ICE even when electricity is produced by coal. When the energy is produced in a more sustainable manner, that time is much shorter.",
"What you're asking is the eternal conundrum of the environmentalist, whatever you do there always is some downside to the technology you use to solve another problem. EVs certainly have the upside that they are very efficient and even if the electricity they use is produced by fossil fuel power plants it will reduce emissions because they are far better at extracting the chemical energy of the fuel than an internal combustion engine.",
"With electric cars that get their charge from the grid, the electricity they get is a mix that mirrors the various types of power plants connected to the grid. In some places like Norway that is almost 100% renewable, in other places like India it might be as low as 12%. However over time as across the globe power plants get greener and more efficient the greenness of electric vehicles will rise everywhere, while regular non electric cars stay the same. There is also a certain economy of scale to consider if you centralize electricity production, that makes things greener in theory however that can be lost again with the loss of energy during transmission and conversion. Switching from paperwork to computer, generally doesn't make things much greener for the lack of paper alone. You do tend to get however all sorts of benefits from easier access and processing and general increases in efficiency which usually have a side effect of being greener than the old way of doing things."
],
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5,
3
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aixnnr | Difference between a container and a Virtual machine | Can someone explay to me, what the difference is between a container and a VM? | Technology | explainlikeimfive | {
"a_id": [
"eer91pp",
"eer84h4"
],
"text": [
"A VM is a simulated computer. It has its own BIOS/EFI and simulated hardware. It can pretend to be something that the host isn't. For instance it's common for VM systems to emulate a Realtek RTL8139 card, even though said hardware might not be present at all anywhere. The virtualization system just makes it look to the VM as if there was one. A container is much thinner. There's no simulated hardware. Mostly it just compartmentalizes software. It hides host processes from the container, it pretends that a subdirectory is really the root, and so on. In Linux terms, a fancy chroot. VMs are much heavier but require little to no cooperation from the guest. You can run say, DOS in a VM, which is a system well before VMs made it into consumer space. The DOS inside just thinks it's running on an actual computer.",
"If a machine is like a car. then a virtual server is like a car carrier with 8 cars on it and the cars are the virtual machines because although they appear to be driving along the road its the truck that's doing the driving. Containers are more like a train with separate compartments they are all in the same vehicle pulled by the same engine, but are still giving each group of people a separate ride. & #x200B;"
],
"score": [
8,
4
],
"text_urls": [
[],
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} | [
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aiyay5 | How people were able to copy games through airwaves broadcast-ed from radio stations? | I'm rather familiar with how copying, cracking and compressing work. But I can't put my finger on how people from the 80s/90s copied their games using cassette tapes. Were the systems translating sound waves into binary or what exactly? Is this used to date? [Check 8:20]( URL_0 ) & #x200B; | Technology | explainlikeimfive | {
"a_id": [
"eerbm9f",
"eerawcd",
"eerj1ug"
],
"text": [
"Back in the old days, modems were [acoustic]( URL_0 ). The data was literally transmitted as sound. So, you could broadcast the audio recording of the program to be recorded on the receiving end. Systems were translating sound waves to digital data.",
"Yes. There were a couple of different storage formats that were based around the concept of converting binary data into sound for storage and then back again to restore it. If you look at old computers like the Comadore 64 they often came with an ordinary audio cassette tape player attached. This was not primarily for making and playing music but for storing data as the computers had limited or no other storage options. The same techniques were also used to connect computers together over the phone lines which as well as to copy games and other applications over broadcast radio and television.",
"Basically, certain patterns of audio were defined as meaning binary data. For example, the [Kansas City Standard]( URL_0 ) used a 1200Hz tone to indicate a 0 and a 2400Hz tone to indicate a 1. Each bit initially lasted 1/300th of a second. Later systems shortened this to 1/1200th or even 1/2400th to allow more storage and faster transfer rates."
],
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[
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[],
[
"https://en.wikipedia.org/wiki/Kansas_City_standard"
]
]
} | [
"url"
] | [
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] |
aiz8m5 | How do ad blockers work? | Technology | explainlikeimfive | {
"a_id": [
"eergan1",
"eerj8b6",
"eerqut6"
],
"text": [
"Ads mostly come from known sources, known websites. They aren't generally served by the same site as you're visiting. So ad-blockers know a lot of these servers, and will block traffic from those servers. They also know a lot of the HTML and JavaScript ads typically use, and will remove them from incoming HTTP responses before they get rendered.",
"Basically, your computer recieves list of components that make up web page. Ad blocker tells computer not to bother with downloading and displaying specific ones that make up ads. Ad blocked needs list of possible places where ads come from to make that decidion.",
"Basically, very few websites are big enough to arrange their own advertisement deals. instead they contact an add company. For said add company, they put some sections on their websites that contain links to the advertisement agencies system, that will supply adds for those sections. This means that if you open URL_2 , it will load some adds from URL_0 So a add blocker can just prevent anything from URL_1 from loading and viola, you can see URL_2 without any adds. This is why you sometimes still see adds even with an add blocker. this means that either the advertising company wasn't known to your addblocker, or that the site owner made his own deal, and hosts the adds on his own site. Of course these days, this is all complicated by add companies getting clever to circumvent add blockers, and add blockers getting clever to still block the adds."
],
"score": [
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"text_urls": [
[],
[],
[
"www.exampleadvertisementcompany.com/advertisementX",
"www.exampleadvertisementcompany.com",
"www.examplesite.com"
]
]
} | [
"url"
] | [
"url"
] |
|
aizgsc | Why do rechargeable batteries lose their ability to hold charge over time, and how can one slow the degradation? | Technology | explainlikeimfive | {
"a_id": [
"eerionu",
"eerkbo8",
"eesp0ip"
],
"text": [
"Inside the batteries are tiny sticky bits, that hold the charge, like velcro. And like velcro, it gets worn, and will hold on less and less, until you have to replace it. Not overcharging helps, but wear is inevitable.",
"On the Toyota prius they limit the battery from being full charged and fully discharged to extend the life of the battery. I believe around 80% and 20% is the sweet spot. I'm sure Tesla and other car manufacturers do the same thing.",
"Batteries in general create electricity from a chemical reaction. Rechargeable batteries use a reaction that is reversible - the elements will combine to create electricity, and if you force electricity through the battery (in opposite direction), the energy from the electricity forces the chemicals to separate and un-react, restoring the battery back to its original \"unreacted / ready\" state. The problem is that chemical reactions aren't like machining tools, and with every recharge the chemicals inside don't go back to the perfect manufactured shapes (rectangular plates, blocks, foils, etc.) that they originally had. As an example, here's a rechargeable car battery [schematic / new condition]( URL_0 ), and [after a few recharges]( URL_1 )."
],
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"text_urls": [
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"https://btstatic.cardekho.com/images/acid-level-indicator-no.jpg",
"https://i.ytimg.com/vi/gqdf_TqF68E/maxresdefault.jpg"
]
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|
aj5eoi | How does the captcha technology work and why sometimes do you have to go through only one test and sometimes 6? | Technology | explainlikeimfive | {
"a_id": [
"eestcn9",
"eesta7h",
"eet1qo0",
"eet23ux"
],
"text": [
"Captcha works by tracking your mouse movements on the screen. It is basically looking for human like interactions, rather than trying to make the questions unanswerable by bots. This is why sometimes it can be as simple as checking the \"i'm not a robot\" box, and other times, having to complete the same test many times over.",
"Great apparently because it's popular. Like me you probably wonder if a sign post is part of the sign, if a blurry building is a storefront and if a car bumper is a car. Guess wrong, back to the start.",
"The part I find the weirdest is that everywhere on the internet, I almost have to redo it every time. For some reason on the playstation website, it works almost every time and it’s a lot easier than others.",
"If you mean Google's ReCaptcha, it checks your cookies and sometimes runs a check on your IP address to compare. Since Google is on almost every site they can monitor your activity via cookies to see how legitimate you are and the difficulty of a test, if any, it will give you. If you are for example signed in to a Google account, browse the web naturally, then there's a good chance you won't be given a test depending on the owners settings. ELI5: Google monitors your internet activity through a unique ID, and makes a judgement call of how human you are. Based on the owners settings, it will either provide a challenge or automatically verify you"
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aj5ppw | Why won’t Instagram change back to chronological order for posts when its users have been overwhelmingly clear it’s what they want? | Technology | explainlikeimfive | {
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"The saying goes, if you are not paying for a product, you are the product. Instagram is free and they way they make money is to promote things that generates revenue, be it from ads or paid promotions.",
"Because it's really a marketing platform, and Instagram has it's financial priorities to consider like any other large corporate body that wants to make money off of social media.",
"Because their testing indicated people stay longer on instagram when the algorithm decides what order the posts are in vs chronological order. And the longer the average user stays, the more ads they can fit in. Long story short, they like money.",
"If posts are not in chronological order, you don't know when to stop scrolling, so you see more ads.",
"It's not what advertisers want. They pay the money, so they get what they want. If ads couldn't displace the content you want, you could visit once a week without missing anything. That would be **very bad for ad views**, so it's bad for the company.",
"Everything everyone else is saying, plus it is MUCH easier to \"hide\" promoted content in your social media stream (so you actually click on it) if you have less of a sense of continuity in your posts."
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aj6txi | How does discord's echoing cancelling work? | How does Discord's non echo work? When I plug a speaker in as a headset people cannot hear themselves when they talk, and my speaker is right next to my mic. I'm just interested in how this works. | Technology | explainlikeimfive | {
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"Sound can be represented by a waveform - think of a graph of a squiggle where the x-axis is time and the y-axis is amplitude. An echo is the same waveform, attenuated a bit and shifted in time. Knowing this, we can implement something termed an 'adaptive filter' that essentially just looks for a correlation between our current waveform and a past waveform. If it finds a high degree of correlation, it cancels out the current waveform on the assumption that it's an echo of the past waveform."
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aj85rl | Why do videos get higher pitched when sped up and lower pitched when slowed down? | Technology | explainlikeimfive | {
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"Sound is vibration. When you visually map a sound wave, it looks like a sine wave. The pitch is mainly determined by how close together each peak of the wave is (that very top of the hill of the wave). If you have 500 peaks every second, it's a 500 Hertz wave. If you have only 100 peaks per second, it's a 100 Hertz wave. When you speed it up by 5x, you're getting 5x peaks per second, so that 100hz sound will sound like a 500 Hertz sound when speed up 5x. Think of just watching a sine wave on TV, and counting the peaks for ten seconds. If you fast forward, you'll count more peaks in the same time frame than playing it normally. That's why stuff spednup sounds higher pitch",
"Speeding up a video literally raises the frequency of the sounds within it and the audible range of low to high is defined by the frequency of a given sound."
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ajavb2 | Why was frame rate tied to physics in the past, and how is it separated now? | For example: Why was it tied in Super Mario 64, and how do modern games with unlocked frame rates not break physics? | Technology | explainlikeimfive | {
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"For simplicity, if you know you render and update screen exactly 30 times per second, might as well just calculate collisions and physics only at those times and assume nothing happens in-between. If you don't know how many frames are displayed then you have to keep a continuous internal state with regular physics calculation(probably way more often than 30/second) and create the displayed frame out of that on demand.",
"The simple way to do physics is assume that each frame takes the same time. So for example if you have a character moving at 3 m/s, and your game runs at 30fps, then you add 0.1 m to the character's position each frame. That's really simple, and it was fine for old console games that ran at a consistent framerate. But if the fps does drop then the character will move in slow motion because the game is still assuming 1/30th of a second has passed since the last frame. You can fix this by scaling the physics calculations by the actual time passed since the last frame. So say your framerate drops to 20fps, that means the frame took 0.05 seconds, so the character moves 3 \\* 0.05 = 0.15 m. This is better, but the results of the calculations can still vary depending on the framerate due to numerical inaccuracy. There are various ways to avoid this such as by doing multiple physics \"steps\" each frame instead of just one. The truth is I don't think there are many games where the physics is *completely* independent of framerate. Chances are the results will vary slightly depending on the framerate, particularly for extremely high or extremely low framerates. Some games are more accurate than others though."
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ajbfyd | Why do old web addresses often redirect to completely random places? | Some background: I was surfing around today and out of nostalgia I decided to check an old website I used to frequent about 15 years ago. This place used to be a European mac-related community, but today it redirected me to a Japanese blog (which according to Google Translate handed out some general advice about lawyers). Turns out from more googling that the old community shut down a decade ago. Over the years I’ve occasionally come across sites like this which look benign, but are unrelated to whatever website used to be there. Sometimes it’s a web hotel shopping for customers, other times it is something completely out of the old target demographic. Why do people keep old barely visited URLs registered for years? Is there any possible reason other than malware with a harmless looking front? Should we be worried when we come across these kind of otherwise innocent looking websites? | Technology | explainlikeimfive | {
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"It is called cyber squatting. The squatters buy such old domains to place a link or redirect you to some web page which they want to make popular."
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ajdcz4 | What is a database package, and how does it work? | I'm trying to get my head around this but the Oracle PLSQL resources I'm looking at don't clarify much. I need a really simple analogy. Help? | Technology | explainlikeimfive | {
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"A package is basically like a folder. It helps you organize stuff. A database allows you to create your own functions. (E.g. a function could delete an entry from two different tables.) You can put multiple of those into a single package and then grant a user the authorizations to use every function in this package.",
"Are you talking about a package in Oracle? If so, it's like a module or a library in a programming language. It's a container for stored procedures, cursors, types, and stuff like that. In the same way that you might package up related functions into a module or library in a regular programming language you would put related stored procedures and their various types and so on in the same package. As an example, let's say you have an application to manage reviews and promotions of employees at a company. The stored procedures you wrote for that application might all go in the same package on the database: list all employees, update and employee's review details, log a promotion for an employee, etc. Now, some of those same tables might be used to handle tax reporting, but all the stored procedures for handling tax reporting would be in a separate package, since they don't need to know about promotions or employee reviews and so on."
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ajdex7 | How is electricity generated? Is there any difference between solar and coal? | Technology | explainlikeimfive | {
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"Electricity can be generated in many ways, but in all cases it is about creating a difference in voltage. Just like gravity causes things with mass to move from high places to low places, the \"electric field\" causes things with electric charge to move between different voltages. (And \"moving charge\" is electricity.) The most common way to generate electricity is by somehow moving a magnet, which creates a voltage difference nearby. A typical electric generator is basically a series of spinning magnets surrounded by wires - an electric motor working backwards. Coal, natural gas, oil, and even nuclear power plants are just big steam engines for spinning magnets, just using different heat sources to create the steam. Some forms of solar power are the same as well, just using focused light as their heat source. Wind mills and dams are also spinning generators, but they use the direct force of the wind and water rather than steam engines. Solar panels are *not* the same - they use an entirely different principle. The ELI5 version is that the light knocks electrons loose from the panel, which is arranged so that they can only \"fall\" back in one direction, causing a net flow. In the same way that a generator is a motor working backwards, these are basically LED lights working backwards.",
"Almost all electricity is generated by using heat to boil water, creating steam at high pressure. That steam is used to drive a turbine turning a generator. Coal, gas or oil fired and nuclear power stations do that. Each has problems to do with using up non-renewable resources and creating waste products. Solar power usually uses silicon photocells to generate electricity directly. That power source is renewable and doesn't produce waste in operation, however the manufacture of the cells may well do so. As it only generates small amounts of power per cell, sunlight has to be collected over large areas, either by covering it with cells or using mirrors to focus it. Some solar power can be harvested by concentrating the sunlight into a water boiler and generating electricity by steam turbine.",
"Regardless of source, the electricity itself is the same. Electricity is basically electrons moving. When you consume electricity you don’t consume the electron, you consume the “movement”. The method of generation is different. You can think of this as “how to get the electrons moving again.” Coal, nuclear, hydro work by spinning a magnet which in turn generates the electricity. The magnet pulls the electrons around creating the movement that is electricity. Coal and nuclear heat up a liquid or a gas, and this moving gas then moves the turbine, in the case of hydro you take water that’s already moving and stick the turbine in its path. Solar works by using the energy from the sun to move electrons in silicon. You can sort of visualize this as a game of pool. You hit the white ball into the red ball and that makes the red ball move. Photons from the sun strike the electrons in silicon, which gives them energy."
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ajemz0 | Can listening to noise cancelling headphones damage your hearing? | Technology | explainlikeimfive | {
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"just the opposite, if you keep turning up the volumn to hear what you want, you are harming your hearing. Active noise canceling sends out waves that are shaped like the incoming waves just shifted so they cancel each other out. So, when it gets to your ear, it has no enegry left to move anything. Think of it this way, one wave wants to pull air mocules one direction, and the other pulls the opposite direction with the same force; neither move. Passive noise canceling uses sound absorbing meterials like foam.",
"Listening to any headphones at a high volume can damage your hearing. However, there is nothing in the implementation of active noise cancellation that is specifically harmful to your ears. It’s just the existing ambient sounds inverted and played back, but it’s still just sound.",
"Certainly not any more than any other headphones would. What noice cancelling headphones are doing: They create a sound that \"interferes\" with the surrounding noice in such a way that effectively there is no sound for you to hear at all. That really means that physically there is nothing there, as if there was silence. And we don't really think that silence damages your ears. Of course that never works perfectly which is why there still is some noice left but that noice isn't louder or more damaging than the noice that would be there without headphones. I don't know if that answered your question."
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ajgaah | How can the weather forcast be wildly different depending on which provider you check it with? | Technology | explainlikeimfive | {
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"Because it depends on the available data and how they interpret it. Someone who had access to most/all weather stations can give a more accurate prediction than someone with a few. And if most provides only have few stations (compared to the total or in certain areas) and they don't really share their data and they have their own algorithms to predict weather, it can make very different predictions"
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ajgdp2 | how come older video games have fewer glitches | Technology | explainlikeimfive | {
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"Part of it was that older video games were simpler, and thus had less opportunity for glitches to arise. Part of it was that older video games were a lot stricter on finding glitches, since you couldn't just fix it later with a patch. Once the game was released, that was it. It was done. While modern games still try to fix glitches before the game is released, they are a bit more relaxed because they know they can fix it later.",
"If you watch speedrunners of older games, you'll learn very quickly that older games have just as many glitches. & #x200B; We just didn't have the internet at the time to hash them out as quickly. If you look at Mario Bros speedrun, they us a good number of glitches. And a lot of speedruns need a glitchless category because the actual glitches make the speedrun no fun to watch.",
"Older video games didn't have the ability to be patched post launch, so what they shipped was what people got. Kind of why a lot of glitches have become infamous. If a game now has a glitch, the developers will just fix it.",
"Much simpler code is a big one. I think Doom 3, from the early 2000s, has something like over 100k lines of code. Super Mario World likely has absolutely nowhere near that. And I can just imagine how big AAA title code bases are these days. Another thing is, when it came out, that's it. No patches (unless you were on PC then you might be able to send in for a patch on floppy or something). So it had to be right the first time around unless you wanted to spend an absolute ton of money recalling all those cartridges and discs and sending Everyone a fixed copy. That would cost them crazy amounts of money, millions at least. Finally, since update patches are so easy to send out these days, Some companies just don't *care.* Lots of big bugs in your software but the holiday season is starting? Ship it now, we'll fix it later, rather than postponing release like the old days.",
"Old video games took exponentially less lines of code. The difference between a 2d nes game and dynamically rending 3 dimensional hit boxes in an online multiplayer is just staggering orders of magnitudes. So even if they made only 1/10 of the errors they did back in the day, it's still many more errors just because of how much more modern games are doing"
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ajjiuw | Why can low budget media sites detect and require you to turn off adblockers, but YouTube cannot? | Technology | explainlikeimfive | {
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"They easily could, but it isn't a war they want to start right now. The tiny gains aren't worth the PR shitstorm and cat and mouse games that would follow."
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ajkfgz | How does Google Maps know where the driver is facing know when traffic is heavy? | Technology | explainlikeimfive | {
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"Where the driver is facing: smartphones have a built-in compass so it can tell your direction. When traffic is heavy: if enough people are using Google maps with their GPS on, google can use that to show how many vehicles are in an area and how long it takes for them to get through certain intersections or areas of road, and put that information on their maps.",
"Imagine a rope. You walk alongside the rope. At one point in time you are at the first meter of the rope. At a later point you are at the second meter of the rope. This is all the information google needs. By referencing location and time it is possible to get a direction. Very easy on our roads which only have 2 directions."
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ajlomm | How does a thermal camera know what's hot from a distance? | Technology | explainlikeimfive | {
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"Every body that has a temperature radiates light. For our usual temperatures, most of that light is infrared. A thermal camera is able to see that infrared light, and simply converts it into visible light so that you can see it too."
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ajneal | Are we ever getting real physics in video games? | I was watching For Honor's Warrior's Den and in the last part a dev comes to talk about character rigging and how important it is. It reminded me that in many video games what we see is nothing but a premade animation to simulate physics. Are we ever getting real physics? I understand water is really hard to do but what about clothes and characters? How hard would it be? Why is there no company that did it already? Here's the link for those interested, the guy is very cool [ URL_0 ]( URL_0 ) | Technology | explainlikeimfive | {
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"That depends on how you define \"real physics\". Really, *everything* you see in a videogame is nothing but animation made to simulate physics, whether it is premade animation, or generated on the computer on the fly. But chances are that for a lot of things that are typically animated/rigged, we're not going to see something that just uses a physics engine, because calculating all of that on the fly is computationally expensive. The reason it is computationally expensive is because in order to have anything resembling collision physics working, for every single thing you want to have collisions with, you need what is essentially an infinite loop running that monitors a certain data point for the position data, and check it against *every other thing that is currently in the simulation*, and do this *60 times per second* for *every single thing in the simulation*. As you add more and more items, the time to complete this (or the processing power required) grows factorally; if I have 3 objects: A, B, and C, then I need to be running 3 subroutines that will each be checking 3 separate position variables. If I'm smart about it, I can pare this down by a bit, but even the best collision detection algorithms require lots of abstraction; because as far as the computer is concerned, those pretty lovingly rendered 4k high-res swords are simple triangles, the humans are as low-res as possible, when it comes to calculating *hit boxes*, because dealing with as few straight lines as possible minimizes the number of checks you have to do. EDIT: And for things like a character model moving, it's a place where you want more control than something like QWOP where you're just controlling, say, the hand node. That's another problem: Unless you're playing For Honor in VR, you'd need to be really prodigious to control all the hand muscles and arm muscles and leg muscles and foot muscles with a controller, so that would get abstracted. And most of the procedural physics calculations would end up with subpar results for what was going on when you moved your arm, and your arm interacted with your clothes/armor... Some games, where there is character customization, have some rules like this: World of Warcraft, for instance, has a subroutine that just runs for physics for the character's capes, to make sure they behave right, but even then it is modifying based on the character model and then behaving based on your state of running/standing, rather than being a full physics object. Look then at games like Skyrim where the Havok physics engine is in full play, and look at some of the weird stuff that happens there. Simply put: We may never have a computer powerful enough to practically be able to do that for everything in a game, and even if we could, these systems work well enough that that power would be better put to use elsewhere TL;DR: It would lag you out super hard if every single pixel of every single item was constantly checking to see if force was being imparted onto it.",
"My guess is, it's theoretically possible to get it pretty close to reality with enough effort. However, such a hyper realistic game would run like crap. Even normal games need a lot of (C/G)PU power. Real world physics are quite complex. Many games already aren't performing that great even without hyper realistic wind blowing through the protagonists hair. Just calculating the motion of every single strand of hair would probably bring the framerate on a very modern system to a single digit.",
"What you are asking is for a video game to calculate and render the trillions of trillions of trillions atoms that makes up the air, ground, etc in real time accounting for heat, pressure, gravity, and a thousand other factors? We will not get it in our lifetime..."
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ajneqs | How can a space probe like New Horizons capture such clear images of fast moving AND far objects in space while it is moving at such fast speeds itself, when my DSLR/phone camera can't even take photos with a decent amount of clarity with small hand vibrations? | I'm [referring to this]( URL_0 ). From my limited understanding of astronomy and astronautical engineering, I know that because space is almost a vacuum, the motion of both the lenses on the space probe and the asteroid itself are nearly constant, making it easier to do motion-tracking of such fast moving objects in space. But in commercial applications like a DSLR and phone camera, they have the economy of scale advantage. Why are the image stabilisation technologies in commercial products so dated? Furthermore, the space probe's image was "taken when the KBO was 4,200 miles (6,700 kilometers) from the spacecraft". How backwards are commercial products when we only have a something like 100x optical zoom among the mass market for prosumers? | Technology | explainlikeimfive | {
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"I would say its because the distances in space are higher, so it moves much less, relatively. Try and take a picture of a mountain while you run on a road. Assuming you can move smoothly (like a spaceprobe) the pics should be clear",
"> when my DSLR/phone camera can't even take photos with a decent amount of clarity with small hand vibrations? > Why are the image stabilisation technologies in commercial products so dated? The brilliant thing NASA did was to make a spacecraft without any hands. The speeds are astronomical, but effective speed varies with distance. It takes a fast shutter speed to freeze a housefly in flight, but a jet in the sky is easy to photograph. The camera on New Horizons is named Ralph, and wit works more like a scanner than a camera. It uses CCDs, which have been supplanted by CMOS chips in high end cameras. But it has seven of them, each one is 5024 pixels wide by just 32 tall. 5024 pixels is roughly equivalent to a 16 megapixel camera, but by scanning and stitching, very high resolution is possible. The sun is fairly dim out there, but the cold temperature helps achieve low noise at relatively high ISO. [Amateur astrophotographers sometimes build coolers for their camera sensors.]( URL_0 ) This was especially prevalent around the time when New Horizons was built. CCD chips build up heat while they capture data, CMOS chips develop less heat.",
"On top of what others already said, I'd add that objects in space move in a very regular motion (line or ellipse) which makes it easier to track the object during capture. On the other hand, you hand trembles in a way unpredictable to your camera, which is why no digital stabilization compensation is possible.",
"You're conflating two different technologies. While consumer cameras and cameras on spacecraft fundamentally work the same way, they're designed for entirely different things. You're comparing apples to oranges. It's not that one is better than the other. They're simply not interchangeable. That's also even the issue here. What's happening is that the spacecraft is just far away from the object they photograph. Think about when you're on a plane and you look at the window. The ground below appears to be barely moving, despite the fact that you're moving at 600mph. You can whip out your camera and take a perfect picture of the ground below you because it's far away.",
"It's not the research that's the problem. You have a lot of different things at work: * Size. You can get higher resolution and faster imaging by increasing the size of your sensor field and the amount of sensors on it. You actual light sensor even on a DSLR is probably a lot smaller than the one on New Horizons, and the one in a smart phone is tiny. The same goes for lenses, mirrors and similar, you can get phenomenal detail just by making everything *bigger* because you can gather more light at once. * Production. This one is twofold, scale and price. * Price: You do not only pay to research and develop a product, you need to actually build it. For a space probe, nobody will blink if the camera will cost a million dollars just to build it. But you will not want to pay $1,000,700 instead of $700 because of a camera. Economies of scale cannot make something infinitely cheap, they can primarily spread fixed costs (like research, building the factory, things you pay only once, regardless of how many things you build afterwards) on a lot of products, bringing them close to zero per item built and enabling you to deal with higher fixed costs like research into more efficient factory technology or similar, but besides that you cannot do much with scale to bring down labor, power and material costs. * Scale: You cannot produce cutting edge technology at scale. For a space telescope or probe, every little piece can be made with highly specialized equipment by highly specialized people. If it takes half a year to build a part, that's ok. But for consumer products, there better be a few thousand each day or even each hour, because it is a mass market. That means you cannot produce at the one-off quality you do for space probes. * Environment. * On earth, even if you hold your camera perfectly still, you have air in the way. Air with different temperatures, that have different density, and therefore break light a tiny bit (this is what makes heatwaves appear). Small dust particles floating in the air can scatter tiny bits of light. All this means is, in out atmosphere, you never have the perfect situation that every bit of what you photograph has exactly one ray of light impacting exactly one sensor on your camera. Some of that light goes elsewhere, but some other light might be scattered to this sensor from elsewhere too. It's never perfect. But space, space is empty. No air to bend light. Almost no dust to scatter any. * Tolerances for space hardware can be insanely tight. You can spend more on just making sure your high tech equipment is delivered to you and launched into space without being damaged than you can spend on a dozen phones or DSLRs. And once actually in space, you have quite constant parameters. Yes, you can have big temperature differences between areas in direct sunlight and in shadow, but there's no shifting humidity. No bumps, no sudden movements anymore. You can create instruments with astonishing precision for space that would not work in consumer technology because your environment is rougher and constantly changing. * Disturbances are almost non-existent in space. As others have pointed out, in space objects have very stable movement you can anticipate more or less flawlessly, especially the relative movement, compared to one another. On earth, even if you do not hold it in your hand, there will almost always be some vibration coming even though the ground. It's way to tiny for you to notice while photographing things on this planet, but it would get in he way if you photograph across the distances involved in astronomy. & nbsp; All this together means you cannot afford that quality of equipment as a normal tool, you would not want to lug it around with you, it would be too sensitive for normal work and if you could afford it and could wield it and it wouldn't break, our atmosphere would ruin your shot anyway."
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ajoq7e | Why do computers, phones, laptops etc. get slower as they get older? | Technology | explainlikeimfive | {
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"Mostly it has to do with how much software you have installed on your device. The more stuff you have running the more computing power each application takes. When you first open your phone it has very few things running in the background. But, after you install Facebook, Instagram, Twitter, WhatsApp, etc. those programs are all running in the background making your phone a little slower. If you want to get some of the speed back you can do a factory reset. This will make the phone much closer to the speed it was when new. But then it will slow down again as you reinstall apps.",
"Short answer: They don't. Longer answer: But they might feel so. This is mostly due to they need to do more work. It's not so much that you installed to much software as that the installed software itself get's updated and gets bigger and more power demanding. What you still can try is to factory rest your phone and see if it is faster. But even if it is I doubt that it still stay fast long.",
"Most people are saying that there hardware does not get any slower, but technically there is some damage to some of the internal components over time just from operating. That can cause performance problems, but the effect will be very small compared to software issues and you won't likely notice it until something fails.",
"That's probably something as simple as you have too many apps installed. I have a Note 4 which was a phone that was announced Q3 2014, so now Q1 2019 it's well on the way to being 5 years old. I've found before it's started to run like crap, slow to respond, crashing, all that kinda thing, and I find if I just go through my app list and have a clearout, it sorts itself out. There'll be apps you just downloaded to mess with, games you downloaded and don't play any more, things you just stopped using. Basically nobody is disciplined enough to just get rid of an app when you don't use it so often (primarily because you've forgotten you've got it) and with phones now having more or less bottomless storage, there isn't the same incentive to keep on top of it. A lot of apps have bits that run in the background, so enough of them can be enough to start hobbling your phone. So try that first. Go through your apps and get rid of anything you don't use any more. To answer the question though, phones and computers don't typically get slower, it's just that the software you run on them gets more demanding, so your computer that was the new hotness five years ago now struggles running some programs. There could be some of that involved too. The version of Maps you use now isn't the same version from 3.5 years ago. That said though I'd still try clearing your apps out. Where I work there's a system we use that's controlled by a computer from 1990, so old it doesn't even run Windows, and it still does the job it was put there to do just fine. Try and install Windows 10 on it though and you'll have problems. Extreme example but you get the idea."
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ajoqiu | How do metal detectors work? | How do they know the difference between metal and other materials? How do they discriminate? Someone please satiate my curiosity. | Technology | explainlikeimfive | {
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"Metal detectors work by creating a magnetic field. When a piece of metal enters this magnetic field the equipment is built to sense the loss of energy that is flowing into this piece of metal, even really small.",
"Metal detectors set up a large magnetic field between the two side posts. When a piece of metal passes through this magnetic field it disrupts the field. Non-metal items don't disrupt the field in the same way as metallic items do. When the detector senses that the field has been disrupted it triggers an alarm."
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ajr3wi | How packets of data work in wireless connections? | I understand waves and electromagnetism as such, but how are "packets" of data transferred with waves? | Technology | explainlikeimfive | {
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"A packet is just a collection of individual bits that are packaged together. There is a header that describes the type of data that is inside the packet, where it's going and where it came from. Then at the end of the packet there is typically a small checksum that can be used to make sure the data hasn't been damaged in transmission. Are you asking about how individual bits are transferred over a wireless connection?",
"Ok. So you have some data. Say a text. Which says \"HI\". It is converted into binary bits i.e. 1s and 0s. Say the easiest way(not the standard) to do that for our case is H means 0 and i means 1. So now since computers only understand bits. They can be taught to understand that 0 means H and 1 means i. But again, the wireless space between an antenna and another antenna doesn't have any idea about what is 0s and 1s. But as you said it know electromagnetic waves. So now we build another small machine which converts 1s into one kind of electromagnetic waves and 0s into another kind of electromagnetic waves (say 0 means shine an yellow LED and 1 means shine a shine a red LED - in the real world we use instruments which deals with radio frequency waves instead of visible frequency). So when a camera(precisely an antenna) captures the waves those machines do the exact opposite things. And there you go, there's a \"HI\" on your screen from another computer. Although the machines and techniques i mentioned have a standard, that everyone around the world agrees on. Like when sending the message you can build a machine which converts 1 into yellow light and 0 into red light, but the person recieving the information should also know what the yellow and red lights mean. And devices are built following this standard and that's why you can read the message on your mobile, tablet, laptop, PC and even on your refrigerator. Edit: Since your asking about bit to physical quantity(waves) convertion. The symbols 1s and 0s are actually randomly selected to represent two states(ON and OFF). Computer engineers are fluent with handling 1s and 0s so the electronic and electrical engineers just hide the ON and OFF ideas underneath 1s and 0s. Whenever a bit is set to 1 by a computer engineer, the electronic engineer has designed the machine such that the 1 will turn ON a certain switch in the computer and same for 0."
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ajsg9s | Even though cell phone cameras have made incredible advancements in the last few years, why do they still struggle to capture things like stars, the moon, fireworks, etc. | Technology | explainlikeimfive | {
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"There is one thing in common with all cellphone cameras and that is they have small wide angle lenses that can collect a limited amount of light and you hold it in your hand So the amount of light from the stars low so you need long exposure times and cell phone camera are handheld so you have problem, To take pictures of stars with larger cameras you use tripods and have exposure times of seconds that result in blur if the camera is not fixed. The moon is not that bright and it is small. You use telescopic lenses perdurable with a tripod on regular cameras to get shoots where the moon is large. There is physical limitation of the lenses you can fit in a camera and the size result in optical limitation. What they call a telephoto is a 50 mm equivalent and on regular cameras that is called a standard lens. there is a reason there is a market for clip on optics for cellphones, size matter for optics, larger is better but the larger they get the higher the cost and weight. To get good pictures of firework you need a bit special way to take the picture so the background is black and you have a sharp fireworks that is not over exposed. The normal auto setting do not work well so some compact cameras have had special preconfigured settings for firework. You can do most of that by using manual setting. Look online for instruction of the setting you should use to get good pictures like URL_0 It is like a lot in photography. The auto setting can be a good start in normal good light condition but if condition changes you need to do that manually to get the best result."
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aju7tw | why/how is a 24 MP full frame camera sensor better than a 26 MP APS-C camera sensor | Technology | explainlikeimfive | {
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"A \"full frame\" sensor is the \"full\" size of a 35mm film frame while APS-C sensors are smaller, originally shrunk to make compact (film) cameras smaller. Given that the pixel count of the sensors are almost the same, the individual sensor elements (think of them as pixels) themselves have to be bigger in the full frame sensor. This means that you get more light per pixel and thus increased sensitivity (less noise or better performance in low light). There's no more distortion with cropped sensor cameras as /u/nokvok suggested; the lens projects a circular image on the back of the camera housing. If you put the same lens on a full frame and a cropped sensor camera, the smaller sensor simply sees a smaller portion (in the middle) of the projected image. In fact, you might see MORE distortion with the full frame camera because the edges of the projected image are usually where it shows up the most."
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ajvahf | Why don’t you get a zap when you have a charger plugged into the wall and touch the metal parts that plug into your phone? | Technology | explainlikeimfive | {
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"text": [
"Your skin is a bit of an insulator and can resist the 5-12 volts that typical electronics (and car batteries) work with. Electricity penetrates into insulating materials depending on the voltage; voltage is like height for falling rocks, the higher the voltage the more penetration the electricity will have across an insulating barrier. So basically your skin is an insulator. 5-12 volts isn't enough to penetrate; 110 or 220 is. In addition, a lot of plugs and connecting wires are designed to have the (no voltage) ground connector as a metal sheath on the outside, protecting the (voltage) pins inside. Safety feature.",
"Very low voltage (5 volts), its doesnt have the oomff to pass through your body. Wall sockets are 110v / 230v AC depending on where you are from. They do have enough oomff to zap you.",
"The charger is mostly a voltage converter. The voltage coming out of the wall is 120V in the US and 240V in Europe. The voltage coming out of most chargers is between 5-10V. & #x200B; The voltage is what causes the zap."
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ajy1dw | why is 3G and lesser cellular reception often completely unusable, when it used to be a perfectly functional signal strength for using data? | Technology | explainlikeimfive | {
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"In addition to the relative data usage already described, the 3G network *is* actually worse than it was previously. The 3g networks are being cannibalized to increase lte coverage.",
"Imagine you're driving on a highway. The \"3g\" part determines the speed limit. This highway used to be 20 lanes wide. It always had some level of traffic, so being able to actually drive at the speed limit was uncommon. There were also some sections that had a slightly higher speed limit (in marketing called 3.5g or HSPA+), but still the level of traffic usually determined how fast you could actually drive. Now, they've built a new 4g highway. It has much faster speed limits, and they've built extra lanes. However to make room for some of those new lanes, they've also reduced the number of 3g lanes from 20, down to 2. So even though it has the same posted speed limits as before, the level of traffic still determines how fast you can actually drive. In fact traffic is usually worse than ever here, but since only a small number of people are using it, the people building the highways mostly ignore their complaints. Now, work is starting to build new 5g highways. We expect the same thing to happen to the old 4g roads, and the 3g road will likely go from 2 lanes down to 1. It'll be there for a lot longer, in case you really need it, but it'll be clogged with traffic most of the time. Edit: typo",
"Because it's all about bandwidth. Bandwidth is determined by how fat a channel is allocated to the signal you're getting. In the 3G days, carriers might have thrown 15 or 20 MHz of spectrum to HSPA+ and achieved speeds up to 42.2 Mbps. Right now, most carriers allocate the majority of their spectrum to LTE because it a much more spectrally efficient (can handle more data connections) and slimmed their 3G channels to the bare minimum needed to service people who still rely on 3G for calls or data. Your 3G connection is probably running in a tiny 3 or 5 MHz channel that gets congested pretty easily.",
"As far as T-Mobile, they have \"optimized\" their service within the last few years. Meaning, they discontinued 3G signals to add more 4GLTE bandwith signals. 3G phones will barely have coverage now. Really though, if you still have a 3G phone it is time to upgrade.",
"Spectrum crunch. Basically it’s like trying to listen to someone in a crowded room. The more people you have to listen to the more difficult it becomes",
"You only get transferred to 3G connection if you have very bad reception these days. It's not relative, being on 3G *is* worse today than it used to the.",
"To oversimplify it, when 3G was the pinnacle of cellular data transfer most of the network resources went into making it work to ensure it was the best available. Now it isn't the pinnacle and the new king, 4G, now gets the majority of resources and 3G is just sort of maintained as a lip service to outdated devices that still use it exclusively. The lower resource allocation means that it runs worse than it used to.",
"I have a feeling this depends where you live. 3G is still perfectly usable where I am, and in fact I quite often switch to it manually when I'm in a busy place (e.g. a sporting event) because the 4G network tends to be slower/more congested when there are tens of thousands of people in one place. Edit: just ran a speed test and got 7mbps down, 3mbps up on LTE compared with 3 down/1.5 up on 3G. Seems pretty reasonable.",
"Think of it like a water heater... if only one person is using it, you have time enough to take a long hot shower. When you’re the last one to take a shower, you’re going to get cold water. When the 3g networks first came out, phones usually were made to be compatible with existing network technology (different carriers operate voice and data at different frequencies) so the phones were to market after the technology was already incorporated. The newest phones would have 3g and 4g, but not everybody had the newest phones so the network was built but not saturated with users. This allowed for the first adapters of smartphones to use peak speeds of 3g, but these speeds slowed as more users upgraded to compatible devices. Now that 4g is so prevalent, and VoIP has become more stable, many major carriers actually lease off their lesser-used 3g spectrum to other carriers who use it for their primary service (VoIP), as well as prioritize that spectrum for their prepaid customers who do not pay extra for 4g. You also have to consider that most carriers have roaming agreements. For example, in the US you may have service with AT & T but if you drop to 3G you would also be sharing that spectrum with AT & T, AT & T prepaid, roaming T-Mobile customers, H2O, Net10, StraightTalk, etc. Nowadays this network saturation of 3g leads to less-than-peak performance, so worst case the minimum supported data speeds depending on the number of users. It’s really no different than trying to stream Netflix while your roommate/sibling/SO is downloading the internet.",
"One thing people aren’t mentioning is that data usage has gone way up also. Every page you visit and app you use is not afraid to use a lot more data. A simple home page might be megabytes of data full of large images and tons of JavaScript that you don’t see. That would have taken ages to load back then as well.",
"Likley because your telecom carrier only invests money and prioritises backhaul bandwidth towards the high profile services. Even sw upgrades, maintenance etc might be prioritised to 4g. This is a generalisation and will vary by country, provider, maintenance contract etc."
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ajzsbp | How do the grooves in records make music? | Technology | explainlikeimfive | {
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"ef06o08"
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"text": [
"[The grooves]( URL_0 ) in a record are basically the [audio waveform]( URL_1 ) that needs to be played. A needle runs along the grooves, being wiggled by the grooves, and the needle then uses that wiggling to wiggle air, which is sound."
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ak2vfa | With the current technology in the 21st century, how can commercial airplanes disappear? | Technology | explainlikeimfive | {
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"text": [
"At the moment, planes are tracked with sensors on the ground, so with the exception of a few sensors which are present out at sea, there’s lots of black spots which mean if a plan enters this area, they’re essentially ‘off grid’ and can’t be tracked. There’s a project ongoing at the moment to move tracking to satellites, so this won’t be an issue going forward. Indeed, the UK’s air traffic control is so impressed with the potential of the technology, they’ve taken a 10% stake in the project. Here’s a link to a news article describing it if you’re interested: URL_0",
"They're pretty easy to find on land when they crash. Over water it is difficult because they sink."
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ak517h | Why and how do rechargable batteries eventually die faster/lose their charge faster? | Technology | explainlikeimfive | {
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"text": [
"Electric is the movement of the particles called electrons. To construct a battery you need two materials. One that wants to give electrons and another one that wants to take electrons or wants to give electrons with a less power than the first one. When you put these two materials into a medium called electrolyte and connect them with a cable, a chemical change happens inside the electrolyte and electrons rush trough the cable from one who wants to give them more to the second. This reaction gives energy to electrons to move. For some specific materials this reaction is reversible to some extent so you can use them to construct a \"rechargeable\" battery. By consuming energy, you can force the electrons back and reverse the chemical reaction that changed the materials. But this is not a 100% efficient reaction and some material end up not converting back to original but converting to another one that holds electrons tightly. Repeat this for 1000 time now you have much more unwanted material that holds their electrons and not wanting to give them out. The ratio between unwanted material and the battery life is not direct. After some unwanted material has been accumulated it can block the original material to efficiently push electrons."
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ak84cs | How did humans train horses to willingly charge into danger or death? | Technology | explainlikeimfive | {
"a_id": [
"ef2emmg"
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"text": [
"Horses, like all animals, don't have a concept of their mortality. They have instincts which tell them to avoid trouble that helps keep them alive. However once you get a horse used to the sounds of warfare, they'll charge right in to wherever you point them. Horses that were too scared simply wouldn't be used."
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ak8auv | Why do football games from the 50's look as if they are slowed down compared to today's games? | I mean how fast the speed of the film is going, it seems as if the video produced by the TV in the 50's is slower than today's. | Technology | explainlikeimfive | {
"a_id": [
"ef2gas8"
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"text": [
"Less effective drugs. Smaller pool of players to draw from. Nutrition. Most important factor is that player moves encompassed a wider range of choices. Less specific and intensive coaching over the player's history and thus less muscle-memory-specific moves."
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ak8tt8 | How does rice get water out of phones? | Technology | explainlikeimfive | {
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"text": [
"It acts as a desiccant absorbs the water from the inside of the device. Water likes to be in equilibrium and if it’s dryer outside the phone than inside the water goes out."
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ak8xex | How do digital thermometers accurately read the temperature? How do they figure it out? | Technology | explainlikeimfive | {
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"text": [
"The most common way is a *thermistor*, a kind of resistor whose resistance varies with temperature - the warmer it gets, the more it resists electrical current going through it. All conductors exhibit this phenomenon, but in ordinary resistors you choose materials to *reduce* the effect, in thermistors you do the opposite. A digital chip measures the current going through the thermistor, calculates the resistance, multiples that with a scaling factor, adds an offset, and hey presto, you have the temperature. The scaling factor and offset are determined by measuring the resistance at two known temperatures, a process known as calibration.",
"A digital thermometer will have an electronic temperature sensor inside it. The sensor can be of different types, but one example would be something called a zener diode. It is a semiconductor device that has an output voltage that will change as the temperature changes. Inside the thermometer will be a little computer on a chip that measures what that voltage is, and can convert that value to a temperature using software, which it then displays on the LCD screen on the thermometer. & #x200B; The sensor could also be a digital one, which works the same way but instead of outputting a voltage, it has a digital communications interface in it that the thermometer computer can talk to to read out the temperature value. & #x200B; There are many different types of sensor out there, using different methods for measuring the temperature. Such as thermocouples, RTD (resistance type), thermistors, diodes. If you want to know how these work in detail, it would be worth googling or wikipediaing the information. & #x200B; & #x200B; & #x200B; & #x200B;"
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aka4b0 | what is the relationship between bandwith in Fourier and bandwidth in networking? | Hello I know bandwidth is the difference between your maximum frequency and your minimum frequency when doing a (fast) fourier transform. But how does that relate to networking where you want to send information from point A to point B? Thanks | Technology | explainlikeimfive | {
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"text": [
"It doesnt. In network bandwidth is how many bits you can send per second. Bandwidth have many many different meanings."
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aka6r3 | If Google homepage had one banner ad how much revenue would it generate in a day? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"For google or the company advertising? Paid by click? Google has 3.3 billion daily searches, 3,300,000,000 views, with 10% of searches resulting in clicking online ads Thats 330,000,000. With 1.6% of those meeting the paid per click requirements, So we have 5,280,000. With Google charging $1-$2 dollars for advertisers per click on search page ads, lets just say they would charge the same for simplicity sake. We could take a slightly less than wild guess and say between $5 million and 10 million a day. Currently Google earns about $100 million a day from advertising, reporting $10.6 billion just from ads in a single quarter"
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akalsw | Why did people believe in old medical practices like bloodletting for so long if those practices were not very effective? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"[Confirmation bias]( URL_0 ). Same reason people still think a lot of things which aren’t true, which includes you and me. Human brains aren’t designed to accurately model reality, they are just evolved enough to be better than pure chance at figuring out what keeps us alive and what doesn’t.",
"Because ability of our bodies to self-heal was/is underrated. I presume logic behind it is following: he was I'll - he got procedure of bloodletting - he is cured - > bloodletting works! If he is dead - > illness was too strong! Nowadays we can see the lack of proof and vulnerability of cause - consequences relation in this example. Plus the famous mistake of survivor...",
"In the case of blood letting it alleviated a symptom of disease, fever. If you're sick and feverish bloodletting leads your body to believe that you are bleeding to death, because you're bleeding, and so it stops spending metabolic resources on causing a fever and shifts them to stopping the bleeding. In this case the idea is that you need to ignore the disease that might kill in days to weeks to stop the bleeding which might kill in minutes to hours. Of course your body doesn't know that the bleeding is deliberate and the people doing the bloodletting didn't know that the fever was an effort by the body to protect from disease. They saw fever = sick, bloodletting reduces fever, therefore bloodletting = curing sickness. They were wrong but this happened a lot in the time before the scientific method an modern science was applied to medicine. TLDR: Bloodletting fixed a symptom but not the underlying problem."
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akax5v | Why are Apple airpods ridiculed so much? | Technology | explainlikeimfive | {
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"text": [
"Because they are so dear I think. That and they have introduced a wire to keep you from losing them."
],
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akcjwx | how are the voices recorded to animated shows/movies? How is the timing of the voice and the animation accomplished? | Technology | explainlikeimfive | {
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"text": [
"Often, the voices are recorded before the final animation. So the animation is done to match the voice, not the other way around."
],
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11
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ake9nq | Why are astronauts allowed to do water droplet tricks on the ISS? | Technology | explainlikeimfive | {
"a_id": [
"ef45kxq"
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"text": [
"Pure water isn't conductive - it needs dissolved salts to become conductive. In addition, the air has a certain amount of water content already. These escaped water droplets will eventually evaporate into the air. Furthermore, if the water droplets were able to come into contact with an electric circuit, they would attach themselves to one connector and not bridge the gap between two, because water is a polar molecule and tends to coat whatever surface it touches. Graphite, on the other hand, will never evaporate and disappear, is highly conductive, and is a solid, so eventually a caking of graphite dust could indeed bridge two connectors and cause a short."
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akfb02 | What is the difference between the World Wide Web and the Internet? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The Internet is a network that provides many services: email, DNS lookup, VOIP phone calls, and **web browsing**. The WWW is the part of the Internet that's visible using web browsing. There is another sorta-WWW part of the Internet, that only visible with the Tor encrypted browser. Some people call this the dark web, but that term was originally dark net, for all the parts of the Internet that aren't email and WWW."
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akg1dj | Why is the audio mix on movies/TV so much quieter than YouTube/online video? | Just something I've noticed where I have to raise the volume on my TV significantly to hear dialogue on an HBO show compared to watching a YouTube video. Is there a technical reason for this, like higher volume required meaning the range of sound can be better for more premium content, or is it just the way things work? | Technology | explainlikeimfive | {
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"Because people who don't know how to record digital files think that red is a great thing and obviously means that it's barely loud enough, as opposed to actual recording engineers who know what they're doing... Sometimes. ( dynamic range)",
"There are different loudness targets (if you will) for different mediums. This is so (for instance) you don't get your eardrums blown out when the next song comes on your Spotify playlist. The targets are measured in units called LUFS (Loudness Units Relative to Full Scale.). So when you mix for TV in the US, the audio should reach only -24 LUFS (that's negative 24). Streaming (Spotify, YouTube, etc.) is -14 LUFS, significantly louder than HBO. Also, as u/audiollectial stated, a lot of YouTubers don't know what they're doing and crank it (and distort it). Additionally, there's the dynamic range to consider. (The dialogue will be more quiet so that explosions and stuff like that sound louder in comparison). [ URL_0 ]( URL_0 )"
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akhmfm | how does a video game cd work? | Technology | explainlikeimfive | {
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"The CD just stores a representation of data, the drive shines a laser onto the CD and interprets the light reflected into binary (look up how a CD works for the hardware info). For a game it simply reads the files from the CD the same way it would read it from a harddrive with one important difference - read speed. CDs are *slow* compared to a hard drive or memory so the game will load as much as possible into RAM and will then stream data from the CD as needed *but* the game will usually be programmed with the fact it's running off CD in mind. Take the resident evil games on the PlayStation, when you went through a door it would play an animation showing the door opening because it couldn't load the next area quickly enough and so hid it behind that animation. It's also the reason older console games took so long to load. Any game designed to run from CD *has* to work around the slow reading speed of CDs.",
"You know when you see the loading screen? It's reading the disc for the upcoming section. Edit: \"it\" being your computer, Xbox, or whatever you're playing on",
"It works like any other CD: the disc spins really, absurdly fast and a laser shines upward onto the surface, reflecting off the microscopic pits that represent the data, and your machine interprets the reflections of those pits and creates whatever's encoded onto the disc. There's an index coded onto the disc that the machine reads to learn what data is on it and where so it doesn't have to scroll through the entire disc to find what it's looking for every time. Improvements in the technology meant that CD drives could be made that could read the data faster. Back in Ye Olde Tymes, CD-based consoles had tiny amounts of RAM and slow disc drives, so they took *forever* to load, kneecapping the pace of whatever game you were playing."
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akhyc2 | How does a touchscreen know the difference between skin and other materials? | Technology | explainlikeimfive | {
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"It doesn't exactly. A touchscreen like the one on your smartphone works by detecting the change in electric fields when something electrically conductive, like your finger, touches it. It's not based on pressure. Something that doesn't conduct electricity, like plastic, won't change the electric fields so the screen won't register anything, but it will register other materials, like metal, just as well as your finger."
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akk8ot | What is the meaning of VoIP in simple terms? | What is exactly VoIP? And why are countries across the world regulating or blocking VoIP? | Technology | explainlikeimfive | {
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"> What is exactly VoIP? Voice over IP. Instead of using the traditional single telephone wire it is a protocol for transmitting telephone calls over an \"IP network\", the same sort of network that computers communicate using. A telephone could be plugged into ethernet just like a computer and complete calls using this method. This avoids a lot of the problems with traditional telephone service in that the data from telephone calls can be mixed in with regular internet traffic which is less expensive and easier to handle from an infrastructure standpoint for many organizations. > And why are countries across the world regulating or blocking VoIP? Usually this is because those countries want to be able to listen in on telephone calls easily. Since VoIP is treated like any other internet data stream it can be encrypted in transit and be very difficult to monitor by third parties. It may also be an effort to protect the money gained by the traditional telephone service, instead of letting people go with a cheaper solution."
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akkn29 | Why do CGI humans still look unnatural? | With all the advances in technology and realistic lighting and mapping and ray tracing, things that normally aren't recognizably CG like cars and buildings and whatnot look normal, while CG humans still seem unnatural looking. What is it about the lighting or movements that makes CGI humans feel not "real"? | Technology | explainlikeimfive | {
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"It's because we're social animals, trained to pick up on subtle emotional queues in facial movements. Faces are the first things in this world that most of us recognize. And it's mostly subconscious. We've been doing it that long. CGI still fails most of the time to get those motions perfect. Maybe the range of motion is dead on, but the skin doesn't stretch and wrinkle like a real face. Or maybe the skin doesn't have enough texture, or light penetrates the skin a little too deep (or not deep enough), or a myriad of other little things. The point is, this part of the brain that is tuned to watch for these things is seeing all this face stuff and the math isn't adding up. Something is still *off*.",
"Humans are still more visually complex than cars. I feel like our computers can handle the simulation, but the skill of artists, while unfathomable to us normies, is still not quite good enough to get over the effect called the \"uncanny valley.\" It's what happens when something looks almost perfect, but \"off\" in a way you'd never find in nature. What trips it can be tough to pin down. But I'd be willing to bet that in the near future, we'll be able to train AI to generate perfect, 3d, animated people.",
"In a nutshell, human beings have a set of perceptions tuned to detecting, recognizing, and rejecting people based on very minute details. It's a survival strategy that helps us recognize friends or foes, and determine a persons intent by subtle cues in their movements. When these things don't add up, even if it's a real person, it can give us a sense of wrongness. And that's an actual person. Something that looks like a person, can be even wronger. Human beings are evolved to recognize each other even though we mostly look the same. Our minds tend to amplify slight differences in the size, proportions, and position of features in order to help us recognize friends, family, and to spot strangers based on a lack of recognition. Ironically the closer to being human like something looks, the more these small differences stand out to our overly sensitive concept of bodies and faces. We call this \"The uncanny valley\". Consider a CGI person, or a sculpture or robot that looks 99.9% like a human being. In fact it looks so realistic, it looks like a dead person. After all the difference between a newly deceased person, and a living person is minimal. It's mostly a matter of stiffness in some features, and relaxation in others, but to us it just looks \"wrong\". That is just one example of a way that something can look like a person, and yet still look un-natural to us because of very slight differences. It gets worse once the avatar, puppet, or robot starts moving. We also have an eye for the way that people and animals move, because it's also an adapted survival trait in that it can tell us a persons intentions and whether they pose a risk to us or not. Consider an ordinary person that has taught themselves to move in an un-natural way. Like not swaying their weight when they walk, or keeping their head perfectly still as their body moves. This looks un-natural to us. A very good actor can use this to look menacing, or like a monster such as a zombie or a possessed person in something like a movie. Consider \"The Ring\" and the way the ghost girl, who is an actress, moves, to look \"wrong\" and freak out the audience. Finally, our visual perceptions are also sensitive to light, and un-natural lighting can also look odd. In nature, light only comes from ahead of us, or above us, never from below. Take a 100% human being, and stick a flash light under their chin pointed up, and suddenly their features look ghoulish and scary as any camp fire horror story could show. So when lighting looks wrong, it can also add to the air of unreality or wrongness of a scene."
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ako0u4 | FM/AM radio | ELI5: How are FM/AM radios able to send/receive music/audio over distances via radio waves and then be able to have it be played back as the actual sound? For something that has been around for probably something like 100 years, I still get a headache trying to understand it. How are the waves turned back into actual audio? | Technology | explainlikeimfive | {
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"You can search to get more detailed explanations, this is a frequently asked question. AM radio has a radio carrier with a frequency much higher than sound. The transmitter changes the amplitude of this signal up and down. The receiver measures this up and down change in amplitude. the up and down change occurs at a sound frequency, and when the receiver sends the up and down signal into a speaker, it makes sound. FM is the same, but a little different. Instead of changing the amplitude, the transmitter changes the frequency by a small amount. Sometimes the frequency is a tiny bit higher, then it is lower. These higher and lower changes occur at sound frequencies, like the up and down amplitude changes of AM, and the receiver feeds them into a speaker to make sound.",
"Radio waves have different frequencies. Radio and visible light are essentially the same thing. They are the same type of thing, with a big differencing being that our eyes can see light, but cannot see radio waves. Light and radio are both called electromagnetic radiation. Xrays, microwaves, ultraviolet and infrared are also all electromagnetic radiation. FM stands for frequency modulation. radio has different frequencies just like light has different frequencies. We see different frequencies of light as different colors. Red is a different frequency from blue. FM works by changing the color (aka frequency) of the radio waves. AM works by changing the brightness of the radio waves. This takes more energy because you need to generate a bright and very bright radio wave. The A in AM stands for amplitude. until recently, both are analog signals. The change in color or change in brightness correspond to the change in the pressure waves that form sound."
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akoc9h | How Game Genie devices work. | Technology | explainlikeimfive | {
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"The game genie was sitting between the cartridge and the console itself. Whenever the console wanted to read from the cartridge, the genie could decide to either give it the correct data from the game, or to give it its own data instead. The genie was designed to look for certain values in the game. For example, if line 25 in the ROM contained the number of lives that you start with in Mario, the genie would wait for the console to read line 25 and return a 99 instead of the hand full of lives you start with normally. Everything else functioned just as it normally does.",
"Essentially it lies to the console about what the cartridge is telling it. For example, if the cartridge says that you take damage when touching enemies, the game genie could intercept the signal and change it to say that you take *no* damage when touching enemies."
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akop46 | Why do Bluetooth speakers take so long to connect to phones that are regularly connected to the speaker? | It’s so annoying | Technology | explainlikeimfive | {
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"It helps to think about the Bluetooth connection like a hose with lots of spurting instead of a nice stream. To make the audio you hear seem smooth, the receiver will usually have some buffer it uses to store the information before playing it. This is kinda like having a bucket with a smaller hole which you run the hose into so that as long as more is going in than out, the stream stays smooth. Once the buffer is full the first time, the audio starts playing and any connection issues get smoothed over. The delay is probably one part the actual connection time and the rest is the buffer filling up so it can start playing."
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akp6ft | How long can an aircraft carrier carry on operating without docking and resupplying? | Technology | explainlikeimfive | {
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"> water desalination system Yes. > generate own food No. > renewable energy source American aircraft carriers are nuclear powered and typically run ~25 years before they are due their mid-service life refit and refuel. Everyone else's carriers are conventionally fueled and need to be replenished by tankers. But even the USN's nuclear carriers would quickly run out of food and need to be replenished at sea. So in the WWZ scenario, we're safe at sea. We no longer have to worry about enemies, so we could probably toss our aircraft overboard (maybe leave some helicopters for making trips to shore), that frees up our massive hanger deck and a good chunk of flight deck for hydroponics; with nuclear powered desalination and some smart water rationing we're ok for fresh water. Food will probably still be an issue, but we can go raid land with our helos. An American nuclear aircraft carrier would probably be a reasonably safe place to be... for the next 20 years or so until our reactor runs out of fuel.",
"Modern carriers have desal and run nuclear reactors so the limits of their useful deployment time comes down to food storage and jet fuel. The depletion rate of jet fuel varies of course, but they typically have only a few weeks worth of food on board. With thousands of crew you can't realistically produce any useful amount of food on board. They're not intended to operate alone for long periods, aircraft carriers travel in fleets with numerous supply and defense ships to support the primary carrier.",
"It depends on the aircraft carrier. If nuclear powered then it is only limited by food. The UK's new QE class (and US Zumwalt class) chose gas turbine and diesel over nuclear because they knew food would be the limiting resource so it cut down on maintenance and cost to switch and just get refuelled upon resupply.",
"No one has mentioned fishing. Without commercial fishing the fish population would recover and provide an ample source of food. There are 18th Henry reports of people fishing the Atlantic fishing grounds with buckets so plentiful were the fish.",
"I suppose if the engines aren't running and you turn off a lot of the electrical systems you could stretch the nuclear fuel. I don't know if you can shut down and restart the reactor at sea. As others have mentioned food would be a problem. Perhaps they could go to shore to get soil and plants and build a farm on deck. I wonder if the government has such a contingency plan."
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akpp60 | Why it is that in TV adverts that involve phones, they use a video which is really badly synced with the finger instead of using the actual application. | Technology | explainlikeimfive | {
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"If you've ever taken a picture of your computer screen, you'll notice moire banding because screen blink in a sweeping way. The same thing would happen if they used real phones. It's the lesser of evils.",
"The badly synced part is just poor directing/filming/editing. The reason they don't use the actual app is because cameras don't pick up the images on screens well. You can see this if you use your phone's camera to look at a computer screen. You'll see a lot of lines that you don't see with your naked eye. Because filming screens looks bad, almost all screens you see in commercials are computer generated and added in later.",
"While others have claimed that this is because of sync issues, camera shutter rates can be adjusted to eliminate that effect. The real reason is that the director and/or client wants the option to replace what is seen on the phone for one reason or another. Maybe they want to show a different app, or maybe they want to change the content in the app."
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akq2yo | Smart scalee | So I received a Eufy Life Smart Scale for Christmas. A scale measuring weight makes perfect sense to me, but what kind of black magic does it use to measure the other categories like BMI, BMR, Muscle Mass, Bone Mass, Visceral Fat, Water Weight, etc.? | Technology | explainlikeimfive | {
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"These scales work by effectively measuring your body's electrical resistivity. A small electric shock is sent up one leg and comes down the other. They then use this value to estimate parameters. It should be noted that these estimates are usually highly inaccurate so take them with a grain of salt. These scales, while inaccurate, are generally very consistent so they can be used to measure relative trends but not absolute parameters."
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akqjnk | Whenever I buy a video game disc, (Xbox, Ps4, etc.) It says it needs to download the game into the console. Isn't the game already on the disc? | Technology | explainlikeimfive | {
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"On modern consoles it has to install the data from the disc onto the console's hard drive. That's because blu-ray drives are just too slow to load data for modern games, so it has to be installed on a faster (although still pretty slow to be honest) hard drive. Usually you also have to download patches, even if the game has just come out. The data that goes onto the disc has to be ready months before the game comes out. So in the time between that data being ready and the game actually coming out the developers continue to work on fixing bugs, tweaking the gameplay, maybe even adding features. So when the game actually comes out there is an update ready and waiting to be downloaded. In theory if the game is single player you can choose not to download the update and just play it anyway. But unfortunately some games are pretty broken without that day 1 patch.",
"Back in the 90s and 2000s, yes. The game would have been fully on the disk. Nowadays disks are almost treated like user licenses. Whereas a digital download would be \"Buy game, download game, game checks if the user has a license, play game\", a disk would be \"Put disk in, download game, license is there, play game\"",
"optical drives max at 27megabytes per second platter (moving parts) hard drives read at upto 240megabytes per second normal platter drive speeds are around 100megabytes per second & #x200B; solid state drives (no moving parts) are available upto 2.3GIGABYTES per second & #x200B; & #x200B; & #x200B; try playing a game directly off the optical drive and you won't even get into the actual game while you still want to play it.",
"Nowadays, no. Often times the only files on the disc are an installer and a form of identify verification. The installer provides your device with the instructions for finding, downloading, and installing the game from wherever it is hosted. The identify verification ensures that you have a real disc in the device and haven't just downloaded a copy of the game from someone else."
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aktv5r | How accurate is the DNA testing done by law enforcement to identify criminals and their victims? | Technology | explainlikeimfive | {
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"Very. Think of out of all the people in the world you have markers from your parents, grand parents, great grandparents etc.. Now they can get close matches if you are a sibling or cousin because a lot of the markers are similar but it is narrowed down so much there are only a few options. Most inaccurate testing is because of dirty samples being collected.",
"The main issues are actually in the methodology and credibility of the investigators, researchers, practices and labs themselves. First, one must actually obtain some DNA. This is basically everywhere, so \"contamination\" (samples having other people than those involved) a real possibility especially in more public spaces. * If you murder a waitress and run, but it's one of my hairs and not yours they pick up at the crime scene because I ate there a week ago, it's MY DNA and not yours that's being processed. We're already out of the ballpark, and an innocent might get convicted while the criminal just gets away. This can be accidental, or it could be caused by negligence or an outright lack of care (\"doesn't matter just jail somebody and be done with it\"), or perhaps even deliberate - either planted by the criminal(s) in question or by crooked cops (bodycam footage has shown planting evidence to be a rather severe issue these days) Then if properly tagged and stored, the lab has to actually test it - rather than simply declare it positive or negative (by lack of care or by demand); which is an issue we've been having when it comes to drug tests. This isn't particularly quick unlike in CSI and the such, because there aren't that many labs and the backlog is immense. If all goes well, and the results are truthfully handed off during discovery, the tests results can be extremely accurate. You just need to ensure it's the right evidence being tested in the first place!"
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akwk0f | What makes the phone respond to the touchscreen? | Technology | explainlikeimfive | {
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"I'm sorry it's long... Hope it helps and hope anyone who needs clarification reads this. There are mainly 2 types of touch screens. One is a resistive touchscreen and another on is called a capacitive touch screen. Let's call them RT and CT for ease The RT was popular in the 1990-2005 era with business people using PDAs with those fancy styluses (stylii?). Basically, what the screen shows you - the actual display (OLED or LCD or IPS technology) is under the touch panel or \"Digitizer\". the RT had two very thin films of plastic like material with a tiny gap between the two, and an invisible circuit that is connected to the motherboard using flat cables. When you press on a point on an RT, you close the gap at that very specific (x,y) coordinate which is transmitted to the CPU by the aforementioned flat cable. The CPU interprets this as a \"click\" or an input inside the device's operating system (like windows, Android, iOS) and it reacts according to what is on the screen. Thus, the RT can be used with any material - fingers, pens, plastic, glass, etc. It only relies on external pressure connecting 2 sheets of circuit. The CT however is a more advanced technology. Again, the actual display lies *under* the digitizer. Here, we follow the same (x,y) principal but the way the digitizer detects touch is a bit different. In the case of RT, the circuit is completed (i.e. a point on screen in pressed, bring the 2 sheets in contact at a specific point) by just pressing, but in the CT, entire digitizer is electrified using a tiny voltage. So whenever something conductive like human skin, water, fruits, etc touch the screen, they form a capacitor that stores charge. A capacitor is device that stores charge and is made of 2 conductive surfaces with a non conductive surface sandwiched in the middle. So one conductive surface is the digitizer's back panel and another is your finger, the non conductive material is the glass! The controller inside the device meaures this change in the electric field due to the presence of such a spontaneous capacitor, and determines (x,y) on the screen.",
"Most touch screens today use capacitive touch. That uses the electrical currents we have flowing throughout our bodies. The gloves that work with touch screens have copper(?) in them which conduct the current and allow it to pass through the screen. Contrast this to older or cheaper screens that used resistive touch that basically just responded to force"
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akyvki | How can we freeze molecules to almost absolute 0? | It makes sense to heat things up you give them energy in various forms but I wanted to know how to freeze things to such low temperature. | Technology | explainlikeimfive | {
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"When you decrease the pressure of a gas, it will cool down. If you compress it, it'll heat up. So you can first compress a gas to a really high pressure, let it cool down, and then expand again - and it'll be really cold. Then you compress some of the cold gas again, and cool that down with the remaining cold gas to reach an even lower temperature. Rinse and repeat, until you have a tiny amount of liquid gas very close to 0K. That's the easy part. To get very close to 0K, they use laser cooling: When atoms absorb a photon, they receive a bit of impulse, that means they are pushed a bit into a random direction. Normally that heats them up. But by using a few clever tricks with a laser, they can make the atoms only absorb photons when they are moving in the opposite direction of the photons. Each time this happens, the atoms lose a bit of their heat energy. This way, they can be cooled to around 0.001 Kelvin or even less."
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akzxhi | How do night vision goggles and cameras work? | Technology | explainlikeimfive | {
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"If we put big spotlights on cameras, they could work just fine at night, right? Only, those big spotlights might keep us awake at night and would use a lot of energy to make it bright for the cameras. Sometimes, you'll see cameras with spotlights of different colors — like red emergency lights. Red lights are less bright and use less energy but we can still see in red light. Blue lights don't get used because blue is high energy and appears very bright to our eyes. As we go along the rainbow from blue to red (ROYGBIV) the left side uses less energy. But what if there was a color left of red, that used even less energy, that we couldn't see at all? There is! It's called Infrared. So we put big spotlights on cameras but instead of using white light, or blue, or red, they use infrared—that we can't see at all, and use camera sensors that do see infrared and use computers to translate the infrared to a color we can see (which is why the screen from nightvision is always montone, like black and white or green and white). You might hear about infrared \"seeing heat\" and it can do that too. But that's slightly more complicated and isn't generally how nightvision cameras work. But if you're curious, I can eli5 heat vision too."
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al2ry1 | Why can torrent downloads resume themselves from their last (download) status even if the (net) connection is lost but browser downloads just get corrupted/lost if the connection is lost halfway through? | Technology | explainlikeimfive | {
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"Let’s say your download is a Lego set you want to build. In one case you have the instructions and decide to get the pieces from different places, it can sometimes take longer but if you get interrupted you still have the instructions and can continue building from where you left off. In the other case you have just one person giving you all the pieces but keeping the instructions for himself telling you how to build your Lego, if you get interrupted and you wanna start again you get a someone else that doesn’t know how much you have already built therefore starts from scratch. Edit: thank you very much for my first silver and platinum, what an amazing way to start the day :)",
"Let's use a physical analogy. Let's say you are trying to copy a book over the phone. #Torrent: * Friend: \"Okay this book is six hundred pages, which one do you want first?\" * You: \"Uh, hold on, lemme make a checklist here, hang on... done. Gimme, oh, page sixteen.\" * Friend: \"Right. [reads page sixteen]\" * You: \"Got it.\" *puts page in a box, makes check on list* \"Let's have nineteen now.\" * [... this goes on for some time...] * Your mom: \"Hang up the phone, I need to make an important call!\" * [... later, you call your friend again...] * You: \"Hey, I'm back. I lost the page I was copying, let's start with... oh... forty-seven.\" * Friend: \"No worries. [reads page 47]\" * [...more pages...] * \"That's all the pages, thanks!\" *hangs up the phone and shuffles the pages into order* #Browser: * You: \"Hey can you just start reading this book?\" * Friend: \"Sure! [starts reading]\" * You: *starts rapidly copying down the words without keeping track of page numbers or anything* * [...] * Mom: \"I gotta use the phone!\" * [...later...] * You: \"Hey I'm back, I have no idea where I stopped transcribing, let's just start from scratch.\" * Friend: \"Awrite, here we go... [starts reading]\" ---- It is also worth noting that some browsers *can* resume transfers. The set of rules they use to talk to the server is *perfectly* capable of saying \"hey I have everything up to page 46, can we just start from there?\". Not all browsers support this natively, and they're not necessarily going to do it automatically even if they do. And not all servers support this; in the book analogy, it would be as if either you or your friend *had no idea of the concept of a page number*. Ask your favorite search engine something like \"resume download safari\" to see what you need to do to make it resume a download; it may be a button you've never noticed, or you may need to install a plugin that will add this capability.",
"Because a torrent is downloading tiny chunks of a file that get reconstructed at the end. When it resumes it simply fills in the gaps. A normal download is a single big chunk that has to start over.",
"Browser downloads can, in theory, resume from the last point. It depends on the server supporting the `Range` parameter for HTTP requests. It's how \"download accelerators\" work, by requesting different parts of the same file at the same time in the hopes that the server is capping bandwidth on a per connection basis. However support for range can be spotty. For example if a server is mainly based on scripts or other dynamic execution it can be tricky to support the range parameter since two requests for the same URL might not result in the same data. This is unlike a static web server where URLs just map directly to files. Bittorrent supports resuming naturally because the protocol is specifically based around downloading files in pieces in an arbitrary order from a potentially unreliable swarm (not all pieces of a file may be available at all times).",
"Lots of incorrect answers here. TL/DR **Bad programmers and greedy server owners that push ads are the reason, there is no technical reason for it.** The simplest answer is that most modern browsers could resume download but the servers break it on purpose/due to a poor design. How downloading torrent works: * your client program get a list of small file fragments (chunks) with information necessary to check if they're good (checksums) * your client program get a list of peers (essentially serving for you as servers) you can download those chunks from * your client starts downloading e.g. 10 of those fragments at once from multiple peers * if one fragment finishes next one is started * if downloading of fragment fails (broken connection, incorrect data) it is retried, often from a different peer How downloading files from browser should work: * you have an URL (link) to a file - it contains server address and path to that file on the server * browser asks for a file, server responds with a size and starts sending data * the way data is sent makes sure it doesn't get damaged in transit, but connection may get broken * if the connection gets broken the browser will (sometimes you need to click \"resume\") ask the server for that file starting from the position the transfer was cut - so if 20MB was saved and file was 50MB only the remaining 30MB needs to be downloaded What can go wrong: * the server can skip sending the size of the file and instead tell the browser - here you will get the data in small chunks - it was designed so it would be possible to send a file that is generated and you don;'t know the size. E.g. when the server compresses some data and sends it to you. Some bad coders use this method to send also normal files for which size is know, and if the connection gets broken the browser has no way of knowing if it got everything * the server may ignore that the browser requested the file starting from 20MB and start from the beginning * the server may have crashed and while it will restart itself soon it will first break the connection and when browser retries it will say that it doesn't have more data, or that it doesn;t have the file at all, or that the access to the file was denied - so the browser won't be able to resume * the server owner serves ads and don't want people to be just able to access the file directly. So when you click on link you get to download page with ads and click \"download\" button - then you get redirected to a temporary link that is valid for e.g. 5 minutes. When connection gets broken and your browser tries to retry it is expired and server says that the file no longer exists. Technically all the programmer would need to do was ensure that the link remains valid for the next 5 minutes if the file is being downloaded in case of broken connection. But they're lazy, don't care or want to serve more ads.",
"In a more traditional browser download the networking protocol was designed that way. Your browser says \"ok webserver, send me part 1 of the file\". Server sends part1. Browser says \"ok, I received part 1, now send me part2\"... rinse and repeat. The protocol is stateful in that you can't go backwards or skip around. Torrent protocols are specifically designed to do exactly this. When your torrent client contacts other torrent clients it asks \"ok, I'm looking for < filex > , who has parts?\" and other clients respond. There's a negotiation and then numbered chunks get exchanged. If you're connected to multiple seeders, you're getting different parts of the file from each one in a completely arbitrary order. However, most torrent clients now can prioritize chunks at the beginning of the file so you can start streaming or watching it while the back part downloads.",
"It breaks up the file into a thousand tiny 1mb files and downloads them in whatever order they can.",
"Torrents: Stacking boxes in a warehouse. Need to take a break? Fine. Come back later and resume stacking boxes where you left off. Downloading in your browser: Dropping your one entire package into a truck from a crane. Need to cut the cord and take a break? No. Your package falls and breaks and you have to start over.",
"> Please explain like I am five. Imagine you want to know what happens in Dora the Explorer so you call up one of your two friends. One friend will start summarizing all the episodes starting from episode 1 up until the last episode and refuse to listen to anything you say. If you hang up and call them again, they will start over from episode 1. This is the default browser download. The other friend will ask you which episode you want to know about and tell you about that episode only. This is how a torrent functions. This is key to how a torrent functions because your torrent phone will ring up multiple friends at the same time and ask about different episodes in order to get the whole summary faster. (five friends talking will describe episodes to you five times faster than one friend talking) It is possible that the original friend could listen to you and tell you the episodes separately. However, back when they made the original phone (the original browser) it didn't include a mouthpiece (didn't have functionality to ask for separate chunks). You would just phone up your friend and they would just start explaining dora the explorer to you assuming that's what you wanted. Most current phones have mouthpieces but some of your friends never learned to listen because that takes effort and would be different from what they originally did way back. However, if you call up a new friend on a new phone, they might be able to restart from where you left off."
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al458z | Heated seats | How do they work? Specifically, why are they not in more cars? With technology, I feel like some things are a luxury and then become common over time. Look at TVs. LED TVs are now cheap since 4k are out. How come heated seats aren't cheaper or seen in more cars? | Technology | explainlikeimfive | {
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"Screens are getting cheaper because of the sheer volume of them being made. TVs, monitors, phones, all sorts of other screens from the one's on fridges to FitBits and Apple Watches to the touch screen on the oven thing at Subway. Heated seats are still considered an option. With many things, what you get is what you get, but with things like cars you can get fairly a la carte. A dozen paint jobs to choose from, several trim levels, and dozens of add-ons within those levels. It's not a \"Well because technology\" thing, it's more because they can charge a premium for heated seats, and those who don't want them can save that money by not getting them. It's not so simple as a couple filaments run under the fabric; almost every heated seat I've ever seen requires the leather seats option which is another cost, and since they're on a 12-volt system but drawing plenty of power they need thicker wiring than a 120-volt equivalent to handle 10x the current, and so on.",
"The actual heater is simple to make, just a coil of wire that gets hot when you pass current through it. Not that different from a toaster. The expensive part is keeping it from *acting* like a toaster. You need sensors and processors to carefully control the temperature to keep it from burning the passengers or starting fires. You need circuit breakers and ground fault interrupters to avoid shocking people. You need beefier alternators to generate the current needed to drive the thing. You might need inverters and step up transformers depending on exactly what voltage/current you need to pass through the coils for best performance. You need multiple versions of all of this to handle different power settings. And it all needs to be hidden either in the seat, under the floor, or in the engine compartment. Probably multiple redundant systems to pass safety regulations.",
"Heated seats, heated mirrors, heated window washer nozzles, heated steering wheels, have been around forever. They’re not *more widespread because they do cost money to make and install and there are huge geographical areas where they’d be useless, it just doesn’t get cold enough. With current technology the real burn is that there are many amazing options that ARE technology based and technically any car from a manufacturer can or does have high tech options *installed* but since you didn’t pay for the option they’re not activated. Audi has had remote operated sunroof /window function for 20 years; just takes a couple clicks to enable. Many manufacturers have found its cheaper (for more streamlined assembly lines) to install most options in EVERY car and add a switch later or OBD interface to activate it. Even if your car didn’t come with fog lights or heated seats, good chance the wiring and most hardware is installed. Just takes a cheap component and/or OBD interface to activate."
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al68fe | Why/how does audio desync with movies or videos while you’re watching when they're pre-recorded? | Technology | explainlikeimfive | {
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"On digital recordings, the audio and video are kept on separate tracks. It's like a video file and an audio file are smooshed together and played at the same time. If something goes wrong, one of those tracks can get a little ahead or behind where it's supposed to be."
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al8xdo | Why does the change machine at Chipotle give me such weird combinations? I get 56¢ as a quarter, 3 dimes, and a penny. What is the algorithm doing to decide I don't get the usual 2 quarters, nickel, penny? | Technology | explainlikeimfive | {
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"Quarters are usually the first to run out, it probably switched over to another combination when they ran out of quarters.",
"Usually when I get change back in lower denominations, it’s because whoever did it wants me to tip them... did you tip the machine?",
"Some change machines are programmed to dispense a few times in lieu of a quarter to conserve quarters and nickles at the expense of requiring dimes to be refilled more often."
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aldshb | How does the Samsung Health app measure heart beat, oxygen saturation and stress levels? | Technology | explainlikeimfive | {
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"For Oxygen Saturation: > SpO2 can be measured by pulse oximetry, an indirect, non-invasive method (meaning it does not involve the introduction of instruments into the body). It works by emitting and then absorbing a light wave passing through blood vessels (or capillaries) in the fingertip. A variation of the light wave passing through the finger will give the value of the SpO2 measurement because the degree of oxygen saturation causes variations in the blood’s colour. URL_0 Heartbeat and stress are measured similarly: Green LED pulses rapidly and then light sensitive diodes detect how much green light was absorbed. When blood is present due to heartbeat, more green light is absorbed. Between beats, less is absorbed."
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ale85b | How do devices reconstruct a piece of information that has been sent by radio waves? | I learned about frequencies and amplitude today but this brought me more questions. Devices understand 1's and 0's to make a program and I suppose that if a 1 is missing or a 0 the device won't understand what you are asking for and here comes what is troubling my mind when data is sent from your router to your device and some of those waves are lost on the way due a wall or because it's far away. How does the device know what to display or to do? | Technology | explainlikeimfive | {
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"There is a lot of error correction in digital communication! There's two basic techniques: We can send a checksum along with the data. If I want to send you 01001001, I can also send \"btw there are 3 1s in the data I just sent.\" That way, on the off chance that one of those 1s gets flipped to a 0 (or vice versa), you'll say \"Oh weird, I only see 2 1s. Can you send that again please?\" We can also send redundant data - say, repeat every digit 3 times. Thus, our message of \"01001001\" becomes \"000 111 000 000 111 000 000 111\" (spaces added for clarity). Only 000 and 111 are valid groups, so if a bit gets flipped and we wind up with 010 or 100 or 110 or something, we know there's an error. We can say \"2 out of 3 wins, 010 is likely to really be 000\" or we can request a new transmission. Please note that both these examples are dumbed-down ELI5 versions of the methods used - in reality, checksums and redundancies are much more sophisticated."
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ale9az | How do you make a car more "reliable" | Seems to me all the awards come after the model of car has been out on the market, how do the engineers design a car with the goal of it being more reliable than the average? | Technology | explainlikeimfive | {
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"In general reliable cars come from years of iterative design and improvement. For example, you might design a car that ends up having 10 common faults. You fix these faults in the next redesign of the car and release it to the market. Consumers then discover another 5 faults and you fix those for the next redesign and so on. This is how companies like Honda work, they also (in general) only make small changes between models to make sure reliability doesn't suffer hugely. You also tend to find that reliability falls when a car company makes a huge overhaul to a car with many changes at once. Car companies also go through absolutely huge amounts of testing on all components - they put all of them through rigorous stress testing, testing in all climates, drive them for miles over rattle strips to make bits of the dash come loose, soak them in gallons of water to check leaks, leave parts in the desert to check UV degradation etc...",
"The answers so far have given you a number of ways that the engineers *look* at the issues to be fixed, but not what is fixed. There are a lot of things that go into the reliability of a car, just like there are a lot of systems, but here's a few things that have been improved over the past 30 years: 1. Computers - More and more of any vehicle is now computerized, and that necessarily adds some complexity. But, it also better integrates the systems so the transmission works better with the motor, the fuel delivery varies based on environment, lots of formerly mechanical parts are now controlled by the computers such as valve timing and throttle response. Vehicle computers have gotten far better by being more integrated, getting glitches fixed, and having all of the wiring, connections and switches made better. 2. Engines, transmissions and driveline parts - Outside of the computer engines have increased in reliability in a lot of ways. Manufacturing has improved immensely, allowing for much tighter tolerances and physical things actually being more sturdy and fitting together better. Chemical engineering has improved many things in the engines; ranging from oils and fluids to the gaskets that fit between the metal parts. This keeps more fluids where they're supposed to be and helps with reliability. 3. Other components - Just like the engine, improved manufacturing, chemical engineering and wiring have improved everything else. \"Rubber\" lasts much longer in the elements because it's not just rubber anymore. There is far more engineered plastics and synthetics in the cars now, so they don't rust like cars used to. Add to that chemical coatings and better seals to keep salt and other things away from the metal parts make them just last longer. In short, there are a lot of things that have improved to make cars much more reliable. My first car was a 1978 Datsun B210 with 100,000 miles on it when I got it. That care was about done. Now 100,000 miles is just a starting point. It's a good thing."
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almszq | How do voice assistants like Siri or Google Assistant say so many things? | I have a non-English name, and it still got it spot on. Almost always say things properly, or at least how I imagine I'd say a word if I hadn't heard it before. | Technology | explainlikeimfive | {
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"I *think* it has a bank of \"noises\" or syllables so all of the noises are put together when talking, so your name will be made from those noises, like it is with most other names"
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alnhep | How do game consoles ( PS4, XBOX One) run games smoothly although they don’t have the same system requirements as powerful PCs? | Technology | explainlikeimfive | {
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"Console games are coded specifically to match the architecture (mainboard/CPU/GPU) present in each console. PC games need to be coded to be compatible with multiple different configurations.",
"If I said \"take a seat\" but didn't tell you where any of the chairs were, (and you couldn't see them on your own). You'll probably be able to sit, but probably not on a chair. If I told you where they were, you'd sit straight on one. Knowing the hardware and software means you can build your program around it. Optimisation is much easier when you know what you're working with.",
"They are heavily optimized systems where as on PC your system isn't anywhere near as optimized as it could be. On consoles they design things for a streamlined experience for gaming, where as a PC is designed for more general purposes... A few other things is bloatware and background software is generally reduced in consoles along with designers knowing the hardware that they have to work with... With PC they have to develop their game to work on a large range of hardwares (which means in some ways they can't optimize it as much) where with a console they know the exact hardware the end user will use and as such can optimize specific to that exact hardware.",
"all the \"optimization\" explanations are mostly BS nowadays there is some catering to the platform but mostly the quality (and rendering resolution) is set low enough to maintain the desired framerate - no magic there e: you can also bump the performance by preparing a version with less clutter (foliage, rocks etc)"
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alrfyc | How does public private encryption work? | How is something locked with a public key opened with a secret key? | Technology | explainlikeimfive | {
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"Let's say Susan and Bob want to send secret messages to each other. They want be sure, that nobody else can read their messages, and they want to be sure that each message they receive has indeed been written by the other (and not by some impersonator). In order to achieve this, they want to encrypt their mails. Encryption sort of \"locks\" the message, making it impossible to read. The encrypted (locked) email has then to be decrypted (unlocked) to make it readable again. For this purpose, they both create a key-pair: one private key, one public key for Bob - and one private key and one public key for Susan. The special thing about those key-pairs is, that a message locked by one key, can only be unlocked by the other key. That means, a message locked with Susan's private key, can only be unlocked with Susan's public key. But it also works the other way: A message locked with Susan's public key, can only be unlocked with Susan's private key. The same is true for Bob's two keys. The private keys are super secret. They are never shared, never given away, never sent over the internet. Susan never tells Bob her private key, and Bob never tells Susan his private key. The public keys on the other hand, can be freely shared with anyone. Bob can put his public key right on Reddit, for all the world to see. No problem. Everyone may have it. This allows Susan to double-check on public sites that the public key is truly Bob's. Bob receives Susan's public key in some similar fashion. Bob then writes a message. First he encrypts his message with his private key. This message now can be decrypted by his public key only. Since his public key is on Reddit, just about anyone can decrypt and read the message. But since the message can be decrypted with Bob's public key, his private key must have been used to encrypt it! And since only Bob knows his private key, this is proof that the message has been written by Bob - and nobody else. Then Bob encrypts the Message a second time. This time he uses Susan's public key. Everyone can use Susan's public key to encrypt a message - but only Susan herself can decrypt those. This means that by using Susan's public key, Bob can make sure, that only Susan can read the message - and no one else can. Bob then sends the doubly encrypted message to Susan. Susan uses her private key to unlock the first encryption - and then she uses Bob's public key to unlock the second encryption. That way she can be sure, that nobody else but her could have read the message, and that nobody else but Bob could have written the message. This works without Bob knowing Susan's private key, and without Susan knowing Bob's private key. They don't have to share their secret key with anyone ever - which makes this a very secure form of exchanging secret messages."
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alsnwj | What is the advantage of shooting RAW images in photography? | Versus, for example, a super high quality JPEG that doesn't need to be "post-processed" by a heavy duty CPU. | Technology | explainlikeimfive | {
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"RAW holds the exact data that was captured by the camera's sensor. When converting to jpeg, a lot of manipulation is done on the data - demosaicing, white balance, color translation, noise reduction, compression etc.. All of these can be configured with various parameters that the camera chooses automatically or the photographer chooses before taking the picture, and results in some data loss from the original raw data. Using RAW allows the photographer to choose these parameters after taking the photo, which allows for more flexibility.",
"The advantage of shooting RAW files, is that you have much, much more control over how the image is processed, and thus, how the image ultimately looks. Also, a RAW file contains all the possible information that goes into creating the image. So when editing, you have more data to work with. One example is bit depth. RAW files are 14-16 bits, while JPEGS are limited to 8. With a JPEG (out of camera), the camera processes the initial RAW file. You have some degree of control over how it is processed by choosing the 'picture style' or 'scene mode' etc....but it's very limited compared to processing the image on a computer with software. On the other hand, the downside of shooting RAW, is that the files do need to be processed before you can print them or upload and view them on a browser etc. It requires more work than just shooting JPEG. JPEG (from camera) is more convenient for some people, but many photographers prefer the control of processing the RAWs in software."
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alt2vg | What stops solar panels from being more efficient? | Technology | explainlikeimfive | {
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"The range of light that they can create electricity from. Most solar panels are utilizing near infrared and infrared (we perceive this as radiant heat). However, this is due to ease of manufacturing and scale of availability. They are in the 20's% (from years ago) range of efficiency. I have read papers and theories on cells that utilize a much wider range of light, including ones in the 80% range. However, these cells have not made it into the mainstream solar energy industry yet. Possibly due to difficulty of manufacture, or general cost of the materials vs efficiency gained. They are constantly improving the efficiency of solar cells and once some of the newer battery tech takes off (ie hypercapacitors (very fast charging and energy densities magnitudes higher than current batteries) , true lithium ion batteries with plastic electrolytic mediums (non flammable batteries than are resistant to damage and have double the energy density of current lithium batteries in which the plastic prevents the formation of lithium dendrites) , vastly reduced cost of manufacturing current lithium ion batteries due to the construction of enormous manufacturing facilities which double the world's capacity to produce li- batteries.) you will see solar energy take a commanding role in energy production. There are also various energy storage solutions that are not solely battery oriented. Using reservoirs to store energy in the form of water pressure, massive near zero friction fly wheels that can store enormous amounts of energy for days, and even 1000 gallon battery like storage systems that use the chemicals themselves to store large amounts of energy. Rambled a bit."
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aludbu | How do game companies make a game engine that requires more power than contemporary computers can make? | Prime example is Crysis, a game where the most powerful PCs at the time couldn't run the game's Ultra mode. | Technology | explainlikeimfive | {
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"Developers will have at least some very high spec machines with the very latest hardware. That might not be properly representative of what will be out when the game is released, but you can estimate that if it's at least playable on that then it will run ok on something more powerful. Plus developers might have access to prototypes of graphics cards before they're on the market. So they can test their games on that before they're released.",
"Game devs want their games to look good for as long as possible. One way to accomplish this is to design the game with the assumption that technology will improve, and designing the game so the specs are better than what currently exists on the market. Crisis is an oddball because it was designed to run on specs that never would go on to exist. They wrongly assumed that the processor clock speeds would continue getting faster and optimal specs have the game running at 5-6Ghz. The problem is that no such processors exist because all the improvements of late have been in core count.",
"It's not that those computers couldn't run that mode, it's that they couldn't run it at anything approaching playable framerates. You can always make the art assets and other things beyond what today's computers can run acceptably, Crytek was just the only one to bother since most games will stop being profitable before pcs catch up, making it a wasted exercise.",
"A lot of it comes down to math. Mathematical formula's are used by software to draw more and more realistic pictures. The more realistic you try to get the longer it takes for the computer to process the math. Something like a video game has significantly more than just graphics going on, which takes up processing time, when you add in more and more realistic graphics you're adding larger and more complex functions for the computer to process. At the time Crysis was released, high-end computers could (for the most part) run the game at the highest setting, however it took so long for the computers to process everything that it was often running at a slideshow pace so it wasn't playable. It's one of those things where at some point you just need more processing power to run everything the game engine wants to do, to be able to run the game quickly enough to make it comfortable to play. For example, hyper-realistic CGI today can take a single high-end desktop computer hours or even days to render a single image. They often use render farms (dozens of networked computers) to render stuff like this, each one either rendering a single image (in the case of animation/movies), or a part of an image, to then be stitched together later. Now try drawing these images fast enough to get 60 of them per second.....you have to either sacrifice quality or get an insane amount of computing power working together."
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alv5wk | How do programs like Siri or Alexa know how to pronounce words with pronunciations that aren’t apparent based on spelling? | Technology | explainlikeimfive | {
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"There are a couple ways that these systems say words and phrases. First is a simple computer sticking together different words and sounds. If the system doesn't have a particular name prerecorded it will give it a best guess. It's pretty obvious to tell when this happens, although the algorithms are getting better. (\"Hello Mr ... Go T Yay\") The preferred method is to have \"the voice\" record all the names. It is very possible, very likely, that the recording team researched exactly how each street/city/landmark is pronounced for each location. The computer system has many different recordings for \"Louisville,\" for example. Louisville in Kentucky will be recorded separately from Louisville in Colorado. When these systems first came out they did not have 100% everything recorded, nor recorded correctly. They receive feedback from people who live there, they have additional recording sessions, and they are always updating the systems. So, if you have a special way to say the name of a street and the GPS got it right, someone either complained or someone on the research team looked it up."
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dbq1fy | the basics of HPC (high powered computers) and computer nodes | Technology | explainlikeimfive | {
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"Well first off, HPC means High *Performance* Computing. It does end up using a lot of power, which is a big part of the design process for big HPC systems. The basic idea is that if you have a big problem that you want to solve, and you can split that problem into a bunch of smaller problems that can be solved independently of each other, then you can speed up solving the problem. You put a lot of computers together (connected by a network that they can communicate over) and let each of them solve a part of the problem \"in parallel\", or at the same time. Then they can put their solutions together to get the solution to the original problem. It's not usually that simple, though. The compute nodes (that's what we call the individual computers that are working on the small problems) often need to communicate during the solving process. Each node might need some information from a few other nodes, or even some summarized information from all of the other nodes about their progress so far. So HPC systems are usually designed with a way for nodes to communicate very quickly, or at least very efficiently for the kinds of problems they solve. This might mean that each node has a few \"neighbors\" that it can communicate with very quickly, or that the entire network has a \"broadcast\" capability that allows messages to be sent to (or received from) all the nodes very quickly. There's no single solution for all types of problems. HPC systems are often custom-built based on the type of problem that they will be used to solve. Some systems don't need a lot of communication between nodes, but they need each node to have a lot of memory to store very large intermediate results as they solve their sub-problems. Other systems have GPUs on some of the nodes to do really fast math. Some are designed to answer database-type queries quickly but don't need to do much math at all."
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5
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dbsanq | How can the NSA activate your microphone while your device is turned off? | Technology | explainlikeimfive | {
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"text": [
"The NSA can't, as far as anyone knows, activate some random microphone on some random guys laptop. If they have a terrorist, then they find a way to load a spyware program which gives them background access, remotely, to the operating system on that laptop. Then they probably load some other program which will enable the microphone output to be packetized and streamed to a server at NSA or FBI headquarters. Now, has NSA struck some kind of backroom deal with Microsoft to load that spyware on with every new copy of Windows? Who knows? But my guess would be, probably not. If that came to light it would cause a shitstorm of epic proportions. Not just for the government but for Microsoft also. So no one is going to sign off on potentially bugging everyone in the entire United States. Any installation of spyware is going to require a wiretap order signed by a judge. I know everyone thinks we are under NSA surveillance all the time but it's not true.",
"I used to write patents for companies in this space (e.g., Ericsson, Qualcomm, Broadcom, etc.) and have seen a number of ways this can happen. The typical way a non-user can activate a resource (e.g., microphone, camera, gps) is by sending a packet containing certain commands to the UE (i.e., cell phone). The UE then receives this packet and the operating system executed the commands, thereby turning on the desired resource. The real trick is getting past the security measures of the OS, which can vary by phone and from country to country. This can occur a million different ways, but the most common is by repurposing other tools, such as adding a resource trigger to a national emergency command. Here is a patent for Broadcom discussing one way this can occur: URL_0 .",
"The NSA wouldn't be very good at their jobs if someone could give you an exact answer. If you know how it's done, you know how to undo it. The last thing the NSA wants is for someone to figure out how they do it.",
"Who says they turn it on when in reality it could always on?",
"Lots of possibilities. The phone has to be built to be always be on or to be woken on receiving a specific instruction. Nsa can set up fakephone towers that your phone will accept commands from including activation of phone features.",
"Side note: thought you might like this. The Soviet Union gave a US ambassador a gift way back when of a US Plaque, inside was a listening device that had no active electronics. It used passive technology to transmit audio. Really neat item, saw a thing about it at the spy museum in DC. Interesting technology given the time in which it was made, very clever. [ URL_0 ]( URL_0 )"
],
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"https://patentimages.storage.googleapis.com/1f/87/fc/cf9a7e370b7c00/US8401521.pdf"
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[
"https://en.m.wikipedia.org/wiki/The_Thing_(listening_device)"
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|
dbsfsx | What is the difference between hotspot data and mobile data? | Technology | explainlikeimfive | {
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"text": [
"I’m under the assumption that it’s still the same data speeds and the laptop is basically toggling your phone’s data. Cellular companies just want to make enough profit as possible and do not want to allow you to use multiple devices on one data plan so they limit how much of your unlimited data you can pull to another device. They want their cut dawg. Sprint does it too. I have unlimited text, calls and data...BUT only half a gig of hotspot use a month before they start charging me for it."
],
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5
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