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8btk3n | Why are some radio stations louder than others even when playing the same song? | Is someone checking to make sure they are roughly at the same level as other stations? | Technology | explainlikeimfive | {
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"The answer has to do with something called **audio compression**. Here's a quick ELI5 on Audio Compression: * You're a teenager watching a movie late at night in your room. * The loud parts are too loud and you mom keeps hassling you to turn it down. But when you do, you can't hear the dialog. * So you buy a strange pet monster from the internet. The monster comes with magic headphones that allow him to listen to the sound from the movie a fraction of a second before it goes to the speakers. * You train the monster to turn the audio down just for the brief loud parts and otherwise turn it up so you can hear the dialog. * That's audio compression. The more you compress the loud parts, the more you can raise the level of the whole signal. That makes it appear louder to the listener. However, compressing too much will make the audio start to sound weird so you can't do it *too* much. **TL;DR** *The reason some radio stations are louder is because they compress their audio more than others sacrificing quality.* **Special Note!** Audio compression is **not the same** as data compression that is used to create MP3s.",
"Because their levels are louder coming out of their station. There is no law about how loud a station can be (too loud would cause distortion and make it sound awful) but there is a law stating that commercials and programming levels have to be similar levels or the station (both TV and radio) are subject to an FCC fine."
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8buto4 | - How does a single speaker create more than one sound at a time? | Technology | explainlikeimfive | {
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"A very common question, here's a sample of the previous questions URL_0"
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8bv8zv | Why is it so easy to read text on our phones when we're holding them ourselves, but when a friend shows you his/her phone it's much harder to see? | Technology | explainlikeimfive | {
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"I believe it's because our eyes correct for the natural shakiness of our hand, but they obviously cannot account for the shakiness of another's, so we notice it more",
"Your brain automatically detects the motion of your hand and body, and uses that information to stabilize the image in your mind's eye.",
"The other posts explain it but just wanna inject some cool info: when you pick up an object, especially one youre familiar with, your brain will literally trick itself into thinking that the object is a part of you. It's why some sports like lacrosse, tennis, fencing, pool, etc the equipment feels like an extension of your arm."
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8bweto | Why do two mics produce a blood curdling screech when too close to each other? | Technology | explainlikeimfive | {
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"It's not two mics being too close to each other that does it. It's a mic being too close to the speakers it's attached to. The sound played out of a speaker is going to be slightly different than the sound that goes into the microphone. It's not an absolutely exact replica of the original sound. Some of the frequencies will be reduced, and others will be boosted. When the output from the speaker is fed back into the microphone, the amplified sound is amplified again, and the frequencies that were boosted the most will be boosted again. And then that sound comes out of the speaker and is picked up by the microphone, and comes out of the speaker and is picked up by the microphone, over and over and over, until the only sound left is the super-amplified frequency that is the one that is boosted the most by the amplifier. That process is called a \"feedback loop\", and so the sound is generally referred to simply as \"feedback\"."
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8bwrb9 | How can we get such good quality photos printed on clothing/t-shirts? | I saw on Twitter people wearing cheesy sweatshirts with their significant other on them. These photos are super realistic and detailed. How can a photo even be translated to a t-shirt? I can’t imagine the process. | Technology | explainlikeimfive | {
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"There are a few ways. You can print on to thermal transfer paper and then use an iron to transfer the image, which gives you great results but will start to crumble quickly in the wash. You can screen print, where you print the image onto separate masks for each colour, then apply dye through those masks onto the shirt - that's expensive for a one off, but is good for short runs. You can get computer controlled sewing machines and actually stitch the pattern into the shirt, which isn't as detailed but is very long lasting."
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8by0oy | Why do some USB cable's not allow a connection with a PC for file sharing, whilst some do? | Technology | explainlikeimfive | {
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"It's not the same type of cable. USB is a four-wire cable standard. Two wires for power feeding and two for data transfer. The cable you have that is not working is probably shipped with a charger for your phone. It only has the two power feed wires, because it's cheaper to produce that way. You can plug it into the computer, the computer will detect that something is plugged in. But because whatever it is is not responding to communications (and no wonder, there are not data wires!) it just assumes that it's not needed for anything and stop trying."
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8by5l4 | How were old game developers able to playtest their games if the games were far beyond current technological capabilities? | Technology | explainlikeimfive | {
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"The gaming industry and the hardware manufacturers work hand in hand in some ways. When you develop new hardware and want it to gain market shares, one of the easiest tricks is to make sure that there are products that actually need it. For a graphics board, the trick is to make the prototype available for developers of graphics heavy software. CAD engine developers. Video editing developers. And, of course, game developers. Making a decent game can take years. But when it is released it's mysteriously having full support for a super-groundbreaking graphics board that has also been developed for years already, that does things none of the competitors have ever been able to before. That kind of thing is not really a mystery. The hardware developer wants the game to help with sales, so they have bene at the developer studio several times with prototypes, made sure the game runs smooth on the hardware and have made sure to plan the release with when the game comes out. Because they both benefit from helping each other.",
"I'm a graphics developer for a big studio. We have very high end hardware for dev machines. My current machine is a 48 core dual xeon @ 2.5ghz, with a 1080ti and a Vega 64 so i can test both manufacturers. Not the best for gaming (lower clock speed) but great for compiling! QA will have faster clock speed machines that resemble consumer hardware, as well as more niche hardware setups like SLI / Crossfire. So the game normally runs fine on our machines. We also do something akin to future proofing. Lets say the game is using 2K shadow maps and runs fine. We decide to up the shadow map resolution to 4K and we get perf hits. We can verify that the scene still looks correct, as it's a perf problem not a visual one. We may leave the option in there as video cards will eventually be able to run the 4K shadow map without issues. Rendering algorithms are also highly parametric. Number of samples for a blur, how many lights we allow, how many marches for a ray march, texture resolution and anisotroic sample counts. We may expose these parameters without fully testing them. Hey they work for N, they work for N+1, they should work for N+2! Mostly because it's pretty much impossible to every configuration matrix possible.",
"Game devs have high-end, cutting edge hardware - sometimes even pre-release stuff. I was doing some database programming for a small (now defunct) game company **back in 2010** and my desktop (not even the machine the database was running on) had 24GB of RAM, a top-of-the-line i7 and some top of the line (GTX \\*80) graphics card. Some of the devs had even *beefier* machines and this *was not* a AAA game title. Beyond that, you can do a lot of testing against the game with graphics settings turned down to low. Other testing can be done while expecting shit frame rates. Once the game is finished, if it's a long development cycle, and the hardware you want to target is available, you can do some final testing but the majority of the work has been completed by that point & you're just polishing things. For consoles, you will often see development machines that have the power of the final machine but are *far* more expensive than the final device will be.",
"Just a quick thing here, pertaining to the last part of your question: Open betas were not as common in the past as they are now. Most games were released without \"open betas\" or \"early access.\" They just released completed games, and would release patches to fix any glaring problems. Betas and quality assurance testing were done in-house.",
"Short answers: 1) You can do lots of development with a bad framerate. Most of what you need to do doesn't require the game to be running well, and most bugs will occur independent of framerate. 2) If performance really is crappy (like with a debug build, or when optimization is needed), you can just drop the graphics quality and resolution until it isn't. 3) You give nice machines to the devs that need them. 4) You cheat the situation if you have to, like working on combat in a level that is just a grey plane with bad guys standing on it. That way your machine isn't busy rendering trees and stuff that drag performance down.",
"> Another meme in the PC gaming community is Crysis and if a computer could play it. It's a meme. Nothing more. Crysis was very demanding on its highest settings. But it was also not very demanding on its low and medium settings",
"Game developers can eventually hide different parts for testing which would lower the load to cpu/gpu.",
"Commercial hardware for professionals, at least historically, was usually way better than the consumer level hardware at greatly increased cost. For example, SouthPark was originally created on $40,000 workstations and years later was done with off-the-shelf iMacs.",
"You can test it in parts. Even if turning on hairworks in the full game would be too heavy for the machines during early development, they could disable everything in the game except the character's head, then test just hairworks and nothing else. If it works, it'll probably still work after turning on all the other things in the game. Furthermore, you don't need 60, or even 30 fps to test if a level is possible to complete. The game developers can change the rules during test play. Even if you have to play a first person shooter at 10 fps during testing, you could just make a build where enemies can't hurt you, just to test if it's possible to move your character from the start of the level to the end of it without getting stuck, or having the game crash. You don't need a fully populated map of 100+ enemies to test if a weapon works correctly, or animates correctly, you only need a single character with the weapon in hand, aiming at a target that is just a cross on a white wall. Despite the crysis memes in the PC gaming community, crysis was fully playable on a mid-end card when it came out. The game did however come with a lot of extreme graphics settings (and even more were patched in long after the game's initial release) that most players wouldn't have a fun time using. It became popular as a benchmark precisely because of this. No matter how powerful a new piece of hardware was, chances were you could throw crysis at it and still have it struggle, allowing you to figure out what its limitations were.",
"Worked in the game industry for a bit. We would get proprietary hardware that wasn't released to the public yet to test with. It was under strict lock and key. Once, a system disappeared and ended up on ebay. Someone went to jail over it. Testing would include a range of systems from the best (unreleased) to very low end. Always felt bad for people stuck on the low end machines. They always found the most issues but it was an exercise in frustration, for sure.",
"Because a lot of computer graphics details really are as simple as swapping out a smaller number for a bigger number. When artists make textures and models, the 'raw' images are incredibly detailed. These detailed products are then sent through algorithms to reduce the poly count, remove details, apply compression, and make it have less of a performance impact. If they want to make their game look prettier they can just put in the option to use less compressed textures and higher-res models. Generally for many of these settings, you can probably assume that if the game runs with *x*, it could probably run with the next higher iteration of *x*. They may run it to see if there's anything crazy causing a crash but likely won't regard performance hits. **EDIT:** Just saw what /u/KazumaID said.",
"Short answer: game developers make the best game they can for the best hardware at the time, knowing the rest of the world will eventually catch up. So as it is being built, only their top-end machines can run it, but by the time of release and shortly after, many people can run it or are willing to upgrade.",
"Not sure why you aren't getting the actual ELI5 for this because the answer is really simple. The answer is that your premise is wrong. It is very rare/doesn't happen that developers would develop a game so beyond current capabilities that they couldn't playtest it properly. Your examples like The Witcher 3 and Crysis were certainly challenging games to hardware at the time and for a while after, but even before launch you could easily play each with a high end machine, we're talking a new build worth around $2k. And if you turn down certain costly graphical settings like the hair physics, the performance demand is reduced considerably. At launch even people with medium-tier computers could play Crysis (in fact Crysis was shockingly optimized for the time, the engine was really really well put together and took much better advantage of things like SLI/XFire or CPU multithreading), they just couldn't max it out. So the answer is that the question itself is wrong, developers never had this issue, it's just a meme born from the gaming community's attitude that you're not really playing a game unless it's maxed out and running 60FPS.",
"\"Bro, we have this engine that is running terrible. You guys have any videocards that might be coming out soon that we could get our hands on early? Aw thanks man. Oh yeah sure we'll put Nvidia on the front of the cover no problem.\"",
"Wow, this comment shows just how much the gaming industry has forced the idea of early access and it's \"benefits\" down the throat of gamers. How did they test it? They payed people to. Also, The witcher 3 and crysis aren't really \"old\" games. And could have still very easily play tested using the beta method. How? People turned the settings down, or off.",
"The games are not beyond the current technological capabilities. They simply require the bleeding edge best hardware in order to run the highest graphics settings at a good frame rate. In the past the biggest issue with this was that nobody really made really high end gaming PCs that you could just buy from the store. Alienware was one of the only companies that built gaming PCs, and they were mid-range at best, and extremely overpriced. So you had to build your own. Add to that high end hardware is expensive. So you have a technical as well as a financial barrier to actually even get a high end gaming PC. So at the time there would be very few people who would even have the means to run those games maxed if they wanted to. Then consider most of the people who could both afford it, and had the knowledge to do it, were older nerds who might not have much time for games anymore... So what you have is a market where real high end gaming PCs are extremely rare, and pretty much out of the question for your typical gamer. Because of that many people might say that those games are beyond the current tech, even many games journalists might make a reference about those games being designed for the next gen, but they are fully capable of running on the current gen hardware, given that you could afford it and build your own system.",
"How old do you have in mind? I'm a game producer from back in the '90s, and it wasn't FPS that we were primarily concerned with but, rather, polygon count, so we would work with 3D acceleration manufacturers like Voodoo, Rendition, and Creative Labs to get our games working on them. They'd supply us with free hardware for our developers and our QA. Even non-3D games, Diamond and ATI, for example, would send us hardware upon request.",
"So there is definitely an answer to your question, but it may not be what you're looking for. The question itself makes some false assumptions, like that no computers could play Crysis on release. As an aside, I came here expecting a discussion on 'old' games, not games that were made within the last decade :P In any case, especially on PC, all of these games were 'playable' on release (and before release, by the devs), on currently available hardware. It's true that Crysis pushed the limits of what was available graphically, and in fact had some settings that wouldn't run smooth on then-modern hardware, but that doesn't mean the games couldn't be played or tested. Typically, turning the graphics down from ULTRA HARDCORE to High or Medium doesn't introduce systems bugs or gameplay issues, so even a game that won't run smoothly at its highest setting can be reasonable tested. As for open betas - sure, they existed and have existed for a long time, but typically AAA titles have rarely had true open betas (true betas that exist for playtesting more than marketing), so I'm not sure what impact this would have. Just as a final note - I wouldn't trust 'meme' culture to inform me on anything, and you probably shouldn't either - even games. It's true that a lot of machines couldn't run Crysis (well) at release, including mine, but games like that would and did run on available hardware.",
"Your examples are nothing that was ahead of technology.. Your question doesn't make sense. They use the available hardware to design the product. The first step of any software development cycle is to get it working properly on your pc.",
"I think this has mostly been answered for modern development however this question would be more intriguing back in the days of vintage 8 bit and 16 bit consoles. They didn't *have* toolkits, SDKs, and engines to run their games in or test efficiently. I'd be interested in learning how those games, typically developed in Assembly, and used low-level keywords that accessed raw memory or low-level CPU functions, how gaming companies of the time were able to design an efficient game and how their software lifecycle went down.",
"They make sure to have a rig that can actually run the game. Larger devs have deals with various hardware manufacturers where they're supplied with the latest hardware in exchange for publicity ir various forms (like the \"runs best on nvidia\" load screen). Another thing I think is important to realize is that how demanding a game is often is exaggerated. Witcher three for example. My gtx 980 powered rig ran it just fine with hairworks enabled. The 980 had been out about a year when the game was released. Many players will complain about bad performance as soon as they go below 60 fps, but keep in mind that a game is fully playable/testable at much lower frame rate.",
"One of the biggest issues with a new game is that drawing the frames would take too long on current hardware. So the developers would simply have a low-resolution version of the game to test with. In fact, the first game I worked on back in 1990 had to work in 7 different graphics mode and one of them was ASCII mode which would run on anything. Tempest from Atari Games is a great example of what many developers did and what happened when the hardware did not catch up the designers vision before the game had to ship. The original vision for Tempest was to have actual monsters (not use the geometric patterns) coming after you. They made the game using what they could draw which was just the pieces you see in the game.",
"> Another meme in the PC gaming community is Crysis and if a computer could play it. Huh, I didn't know about this since I'm not a PC gamer. Back at that time I was a manager for a QA group at EA. Our project had been delayed so we put the call out to see if we could help any other projects. We heard back from the team working on Crysis that they could used some additional coverage. Then they sent us the min spec and the recommended spec. Nobody on the team had the min spec (our project was a console game so we didn't need great PCs). We asked around the (very large) studio and only a handful of PCs could run the game at all, and those were needed for the developers. So we never got to help test Crysis.",
"I can't follow. You're implying that \"in the olden times\", game developers made games which would have been far ahead of their times and only suitable for top of the line PCs? This wasn't the case :) Game devs usually code for the lowest-common denominator, so a that a game will run on as many as is reasonable PCs. (With very few exceptions). It is reasonable to think that any \"sane\" game devs/developers plan their games in such a way that they can assume that their games, when finished, can also be played by many. In such cases where it can be expected that making a game might take a very long time (maybe where they start developing but think the game will be ready only in some years), I can see devs testing on the \"best\" high-tech hardware that's available at a given time, since they can assume that the best and most powerful PCs they are using to develop and test their games may be common and affordable when the game is done. Say, I could make a game now developing on and for a 1080 TI or better GPU. Now, not many have such a powerful GPU, but in 2-3 years I can expect the game to work for most people since most will have a GPU that is like an 1080TI or better."
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8c0qkg | How do lane departure warning systems work? | Technology | explainlikeimfive | {
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"They have cameras or other sensors that detect the lane markers. When the lane markers move outside a certain part of the sensor, and the driver hasn't used their turn signal, then the car notified the driver that they appear to be departing their lane. Usually there may be a camera mounted near the rear view mirror."
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8c0wdm | How do remote controlled cars work? | Technology | explainlikeimfive | {
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"A radio sends commands to a controller in the car. That in turn sends electrical signals to the various motors and solenoids that operate the mechanical parts of the car. This can be super basic in a battery powered car with simple steering, or increasingly complex as you approach full sized gasoline powered vehicles.",
"An RC car consists of the radio system \\(transmitter and receiver\\), the motor, motor speed controller, steering servo, and battery. Each function like steering and throttle are on separate channels, usually channel 1 for steering, channel 2 for throttle. When you hit the throttle the radio transmitter sends the signal to the receiver on the car. The receiver will send the throttle signal to the motor speed controller, which then sends power to the motor. When you steer, the receiver will send the steering signal to the steering servo which steers the wheels. The battery pack powers everything."
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8c0yb6 | How software tracking eye motion works | For example [this post] ( URL_1 ) showed what the eye was looking at when walking over terrain. [This video] ( URL_0 ) shows what kids and artists lol at when trying to draw. How does the technology know where the person was looking. | Technology | explainlikeimfive | {
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"How can you tell where people are looking at? By taking two 'video feeds' your eyes, processing it into a psuedo-3D image with your brain to make an estimation based on where their eyeballs are pointed at, the distance the person appears to be from you, and any objects of relevance in the area they may or may not be looking at. How does software do it? Basically the same way."
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8c1m4h | How did the old telephone company systems redirect you to recorded messages ('no longer in service', etc.) before computer routing and digital audio etc.? | Technology | explainlikeimfive | {
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"These messages are called \"intercepts\". Before they were digital audio files, they were, depending on the system, either on short-reel tapes playing the same message over and over, or on a magnetic spool on a drum that had multiple messages on it. Either way, the system set the timing to play when it was at the start of the desired message."
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8c78c0 | How can a virtual machine's disk drive be larger than the physical HD of the computer? | Technology | explainlikeimfive | {
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"You can set the virtual hard drive size to be as large or small as you like - the VM can *present* it with whatever upper limit you specify - but that won't allow you to store that amount of data. Instead, the VM can allow the virtual hard disk to take up only as much *real* disk space as the data saved to it (plus some filesystem overhead and so on). That lets it be stored on a hard drive smaller than its notional capacity, but it'll still have problems if the underlying hard drive fills up. The advantage of this approach is that you don't have to worry about giving over a large chunk of your hard drive which you'll never actually use to the disk image (risking running out of space in the host OS), or running out of space in the virtual machine because you sized it too small in an attempt to avoid that."
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8c78y3 | How come the U.S doesn't use PIN-verification for card purchases? | Technology | explainlikeimfive | {
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"We tend to have a lot more credit cards and don't typically have the ability to change the PIN. That makes it much more difficult and impractical."
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8c9ccp | Why were scientists in the late 1800's suddenly able to isolate and identify a large number of certain compounds and drugs? | I've been reading a lot of articles on drugs and medications and it seems they all suddenly appeared out of nowhere in the late 1800's, but I could be wrong I don't know | Technology | explainlikeimfive | {
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"Industrialization. The primary limit on scientists isn't really their imagination so much as the instruments they have to collect, process and verify information about the natural world. The revolution of the 1800s was the rise of easily accessible, high-precision instruments and tools. Being able to apply consistent and predictable heat, being able to precisely measure mass, etc. - these allowed scientists to examine the world in ways they could not previously.",
"Because until 1780 scientists believed into the phlogiston-theory. They had no idea how elements worked and tried to explain a lot of chemical processes with an purely theoretical element: phlogiston. In 1780 Lavoisier was able to proof, that some chemical processes invoke invisible substances. Gases. We know some of these today as oxidization. The phlogiston-theory was busted and scientists started to discover elements and chemistry as we know it today, began. EDIT: URL_0"
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8c9isq | What happens in the background while we see the "loading screen" in video games? | Technology | explainlikeimfive | {
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"Generally, Data is being loaded from the harddisc into the ram memory. RAM is a lot faster than your harddisc, even if its a SSD, it just has the handicap of losing all data when its unpowered. So we store data on harddisc's that are slower and cheaper, but retain data without power. Then when we need it, we load the data from the harddisc into the ram memory, and use it. When game devs can get away with it, they hide loading screens these days, for example, by placing the character in a slow ass elevator (Think Mass effect)",
"Game assets are decompressed from their storage form as needed for the current part of the game, which involves reading from the disk, processing, and storing in active memory. Some of that data (mainly textures) will be transferred to the graphics card memory to be used."
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8cajad | Why is it important to have electrical wiring grounded? Is my family at risk with older wiring? | We are working to replace the wiring in our home but are having a very hard time with it. We can't afford the cost of a professional electrician and keep hitting roadblocks. We're now contemplating whether or not we need to do the job at all! Finding easy to understand information about the risks of an ungrounded home is difficult for us. The house was full of only two-pronged outlets and we have all 3 prongs to install, just ignoring the spot for the ground wire. Risks? | Technology | explainlikeimfive | {
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"In electricity, you need a way for the current to get to your device, and a way for it to get back to where it came from. In houses, this is hot and neutral. But there's a secret -- neutral and ground ultimately go to the same place. The problem is that neutral carries the same amount of current as hot. So if something goes really wrong, it's possible to get injured from neutral. Ground was created* to have a non-current carrying place to dump power in case something goes wrong. Edit: *obviously we did not create ground. I mean was introduced as part of electric code. Well, not long after ground became standard, someone invented the GFCI (ground-fault circuit interrupt). This is a device that looks at how much current is going through both hot and neutral. If there's a difference, that means that there's current going somewhere that it shouldn't (like a person, maybe), so it shuts off the power really fast. A friend of mine told me once that if GFCI had been invented just a bit sooner, grounded house wiring never would have even been a thing. And sure enough, NEC section 210-7(d)(3) says that if you don't have any ground, you can install GFCI and label it as \"No equipment ground\" (or have a regular outlet protected by another GFCI outlet). It's actually safer to have a non-grounded GFCI than it is to have a grounded non-GFCI. So, to summarize: if you have older wiring without ground, one of the best things you can do is to make sure that everything is GFCI protected. Source: URL_0 Note: I am not an electrician. Make sure everything you do is up to code, and ideally have a licensed electrician perform your work.",
"Tbh, the easiest way to make sure in an old home is to replace all your breakers with \"arc-fault+gfci\" breakers. Definitely not the only option but that makes it a lot harder for things to go wrong.",
"It is the equipment that should be grounded. In the case of a fault (like a broken wire touching casing of equipment) to make it safe, the circuit protection should activate and prevent damage or injury. Depends on how old the wiring. If there is a grounding wire that is in tact and continuous through your installation, then you should be fine. Insulation does degrade very slowly over time.",
"Electricity is lazy. It has 1 job \"Find the shortest path to ground\". If that path takes it down a wire, no problem. If that path takes it down your body and out your feet, that's inconvenient for living. With a grounded outlet, there is a safety measure there for devices using 3 prong plugs. The electrical ground for the device, can dump directly into the actual electrical ground in the wall outlet. So if a dangerous voltage leaks into something like the metal chassis of the unit, it is immediately discharged through the plug, instead of through the next person to touch it. Before 3 prong plugs, electric grounds were sometimes done by attaching a wire to a special screw near the outlet. It is possible to convert outlets like that to 3 prong simply by changing the outlet out, provided the gang plate has a ground wire inside (usually green or bare copper). Electrical systems ground goes to the actual ground, dirt and all. In order to be effective, the grounding rod must be driven deeply into the ground, made of a material which will degrade slowly in soil so it doens't rust out in a few years, and it must be electrically conductive. This means it has to be driven deeply into soil or clay that is conductive. When the house is wired for electricity, this is done by the electrician or subcontractor and measurements are made to ensure the ground connection is good. Ground wires can then be ran to the outlets around the house via the gang plates inside the wall. Outside of safety discharge, the ground wire should have no current on it, so it can be left un insulated, or a plain copper wire. An interesting thing can happen though when a house has more than one ground, or when there is a difference of potential between the ground connections in various outlets. You can get a ground loop, which can cause DC voltages (like a battery) to exist between two grounds, and this can lead to tingling when touching an appliance while also touching another ground (such as holding a USB device, while leaning over to open a refrigerator) noise in audio equipment plugged into more than one ground, etc. For this reason, it's sometimes necessary to isolate the ground either with opto isolators, or by not using a grounded plug."
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8carx0 | Why does the cursor run off the screen at the right and bottom, but not the top and left? | Technology | explainlikeimfive | {
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"The cursor is only the tip of the little cursor icon. Your cursor is a single pixel with an arrow icon hanging off it down and to the right. If you take your clicking pixel to the top left of the screen, the arrow icon is still visible. If you take your clicking pixel to the bottom right, the icon cannot be displayed below and to the right of it.",
"Because the actual pointer is the top left of the cursor, what if you needed to click on something on the far right of the screen and the cursor stopped at the edge of the cursor? There would be a kind of dead zone that you wouldn't be able to click, having the cursor run off the screen ensures you can click anywhere on the screen",
"it’s all about the “pointer”, when you go to the top and left, the actual pixel you’re aiming at is at the edge of the screen, so you cannot go any further. On bottom and right, however, to get to the pixel at the edge part of the traditional cursor has to “disappear”."
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8cbtpe | What is the difference between the 'same' graphics cards | Technology | explainlikeimfive | {
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"NVIDIA makes the main graphics chip for the graphics cards, but they also require a lot of other chips and stuff like RAM and power delivery regulation. So it requires those, which all come together to form a graphics card. NVIDIA however doesn’t particularly want to be the one to deal with customers, so they sell their chips by bulk to other companies, who then assemble these details along with he chip to sell to you."
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8cejok | Why do the "black" pixels on your phones bootup screen seem bright? | Technology | explainlikeimfive | {
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"Most phone displays have a light *behind* the display. It shines through a translucent panel of LCD pixels. The \"black\" pixels can only block some of the light, not all of it. Some newer displays use a different technology where the pixels themselves emit the light. On these displays, black pixels are actually black because there's no light.",
"I believe it is because of the backlight. There is a light that illuminates the screen and makes it seem bright when you are using the phone at all (the intensity changes when you mess woth brightness at all). During boot up that backlight turns on before the screen and you get a solid bright black screen."
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8cfe3t | How can an EKG give an accurate reading of the health of your heart in such a short amount of time? | I have to be honest, when going in for my yearly physical and they hook up the EKG paraphernalia, I'm always left unconvinced of the diagnosis after such a short amount of time on the machine. How can they be so sure? | Technology | explainlikeimfive | {
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"It's the current electrical activity of your heart. It is a great diagnostic tool for the heart but obviously can't predict the future. They don't need more than a 6-12 second printout to check that your heart is working normally and not dying. That same printout won't tell them in the least if you have all kinds of plaque buildup outside your heart that could cause a heart attack 2 days later. An EKG gives tons of info. All the info the EKG gives can be obtained really quickly. You may be doubtful because you think it's diagnosing more than it really is. To further expand. Dead tissue in the heart causes electricity to move different, an EKG sees this. A normal EKG means all your heart tissue is alive. Irregular structures in the heart can cause feedback loops and cause electricity to move abnormally, the EKG can show this. Electrolyte imbalances cause electricity to do weird stuff, EKGs can see this. Electricity also corresponds with the speed of your heart, which combined with a pulse can tell a provider if there is a mismatch. Hearts also beat regularly so abnormal beats that don't match the other rhythm can be seen in an EKG (though these are sometimes harmless). Seeing the degree of electrical activity and the path it takes tell you a lot about the heart. Printing out a 6 second strip to look over can give you 90% of that info. But like I said before it can't tell the future. A lot of heart health relies on other parts of your body and general health and an EKG can't tell you if those are about to fail.",
"The waveform shows the electrical signals going through the heart, and the heart is a very precisely timed/coordinated device (it's not just pump & relax...different parts of the heart need to pump or relax at specific times). With the EKG, they can see if the signals are coordinated properly. Sometimes there's too much time between the signals, sometimes Signal B comes twice before Signal A has had a chance to repeat. And since most of these issues are constantly repeating (especially if the problem is bad enough to care about), they don't need a whole lot of time.",
"Also, an EKG, read by someone with expertise, can reveal a surprising amount of detail and history. Poorly read, an EKG is of little value."
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8cfwpc | Why does a video seemingly get "stuck" buffering, but after a refresh there are no more problems? | Technology | explainlikeimfive | {
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"Refreshing seems to solve a lot of stuck website issues. A popular website or app will have many duplications of hardware resources at their data center, some of which are chosen for you at random. Sometimes the combination of hardware you are assigned to is having issues, and it can hang. When you refresh, you're dealt another combination, one which works.",
"Many streaming sites use UDP to send large packets of data: essentially, the server sends video out and don't ask back if the target has received it. So if your computer doesn't get a part of the video, the server won't notice and it will keep sending video. If the web player is written correctly, it'll ask the server to rewind and your playback will continue smoothly eventually. If the player hasn't been written properly, though, the player will never ask for the packet again or it won't be asking for it correctly (either the session has been invalidated, the player has sent out too many requests, etc) so playback will be stuck. When you refresh the webpage, it does a refresh of your session and it takes some time until the page is loaded so you can send a new request for video. Note: this are only some of the reasons it can mess up. There are probably many edge-cases I haven't covered.",
"because a part of software(maybe even hardware) that is involved in the process of getting your video to play is badly designed and ran into a problem (there could be many different problems) resetting the whole process can cause it to run like it was planned since (aside from cookies or eventual account data) you should get to start from 0 every other answer here trying to describe in detail whats exactly wrong is probably wrong because there can be many problems and even more symptoms.",
"In a followup question, why can Netflix nail every stream every time. I don't think I have ever had a failed or shitty Netflix stream and the only place it ever buffers is with extremely slow connection speeds. Meanwhile youtube its a daily occurrence to get a fucked up stream and don't get me started on hulu. Why is netflix so much better than everyone else at delivering my content?"
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8cguqa | Why doesn’t pointing a camera at the sun directly damage it, like our eyes get damaged? | I know we’re living things and cellular components are different from electrical components, but what is it about cameras that prevents the damage? | Technology | explainlikeimfive | {
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"Nothing much. Cameras can be damaged by sunlight, they just can take a bit more abuse. But you absolutely can damage your sensor and even melt internal components by pointing a camera at the sun carelessly. DSLRs are a bit protected in that the sensor is normally only exposed to the light for very short periods of time, but it still can melt the shutter, and a long exposure of the direct sun is a bad idea. Lasers can also be dangerous. [Here's an example]( URL_0 )"
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8chdih | How did people get domain names before domain name registries were available? | I don't know if I'm asking this right,,, | Technology | explainlikeimfive | {
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"As a layperson, you are asking it correctly. The short answer is that people kept text files of names and addresses and shared those files with other people. You can still maintain a hosts text file for private networks or domain name overrides. When you use a domain name, you're really asking something else, a Domain Name System (DNS) server, for the domain name's IP address. The DNS server is like a phone book (does a contemporary five year old even know what a phone book is???) in that it maps names to phone numbers and street addresses. As long as the modern Internet has existed, there have been DNS servers to provide address mapping, as u/PacoFuentes pointed out. Here's where it gets interesting. Your question is kind of backwards because the registries were created so that DNS could work. In fact, domain names were created for DNS to function. Before the Domain Name System existed, the network was called ARPANET. ARPANET was much smaller and very different from Internet. When ARPANET started, it was only a handful of computers and the researchers working on it maintained a text file containing the host name and the address of all the other computers on the network. As the network grew, the methods of sharing hosts text files changed several times until the Domain Name System was born. If you want to know a little more about it, you can read about the [history of DNS]( URL_0 ).",
"They didn't. There has always been domain name registration. If you mean the companies like GoDaddy etc, they're just registering you with the actual registrar (Network Solutions) for you, for a fee."
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8ciiqw | How does ABS brakes work on a motorcycle? | Technology | explainlikeimfive | {
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"It works exactly the same as on a car. The ABS monitor's wheel speed. If it sees a wheel starting to lock up by its speed dropping faster than other wheels, or than the vehicle could possibly be slowing down, it does a few things: 1- Isolate that wheels hydraulic circuit to prevent any further braking pressure. IE. Even if you squeeze/push harder, no more pressure is getting to the wheel. 2- If necessary it can then reduce that circuits pressure. It does this by opening a valve that bleeds the pressure into an accumulator. That fluid is then pumped back to the master cylinder side by an electric pump. Its this pumping that you feel \"pushing\" the lever/pedal back at you. 3- Once the control module sees the wheels speed recover it will re introduce that wheels circuit to master cylinder pressure (the pressure you are applying). Usually you are still naturally applying too much pressure for the available traction, and the wheel will begin to lock up again and the cycle repeats. (Wheels slows > isolate wheel > reduce wheel pressure > wheel speed recovers > reintroduce driver input). This all happens very quickly and results in the \"pulsating\" pedal/lever feeling. Mechanical the system is pretty simple: -2 electrically controlled valves (normally open inlet and normally closed outlet) -An accumulator -A pump -2 check valves All arranged in a way that would be easy to explain with a diagram. The real magic is in the software running in the control module."
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8ciol5 | Why do some video games run better on "medium" settings than "very low" | Technology | explainlikeimfive | {
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"I actually just watched a video on this, but with regards to ultra settings versus high settings. Essentially the game runs better on “more common” settings because the developers try and optimize the performance of their games on those more common settings rather than the ultra or very low settings, where most of their consumers won’t be playing at."
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8ckiv9 | CGI in Films | Technology | explainlikeimfive | {
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"Introduce her to collages, cutting pictures out of magazines and gluing them into fun creations together. The connection to film goes like this: \"If we take a lot of pictures of the actor while he pretends to be eaten, we can glue those pictures in the mouth of a monster pretending to eat, and it looks like he's being eaten.\"",
"I always tell my kids that CGI is just extremely lifelike puppetry. You could also show your daughter some photorealistic pictures that are obviously fake, like an image of a blue strawberry or a mouse wearing a top hat. Tell her there are people who can make paintings on computers that look like the real thing, and computers can put them into movies to make them look real. Sometimes when I'm watching a show with my kids, I'll stop and ask them, \"Okay, do you think that person really died? Or are they just pretending?\" and to the older child, \"How do you think they did that special effect? Fake blood?\" It helps to take them out of the story for a moment and process what they're watching as fantasy."
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8ckp32 | How does CAPTCHA both screen bots and build machine learning databases? | Technology | explainlikeimfive | {
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"They have a database and part of the key. They show you 4 signs, 3 they are sure of and 1 maybe. If you get the 3 they know right, then your vote counts for the 4th one. If 500 users who got the 3 known signs right agree about the 4th one, that's pretty good evidence that their answer is the right one. Add that sign to the database and put the next unknown one into the captcha."
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8cnzbf | "SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon and then land on a bouncy house". | Please explain how "SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon and then land on a bouncy house". I have a general understanding of how it's possible with the booster,but the upper stage? Mathz? Anyone care to hypothesize? | Technology | explainlikeimfive | {
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"The problem with getting the upper stage back to earth is that it reaches orbital velocity when deploying its satellites. That means that instead of falling back to earth on its own like the first stage, they have to activate the engine and slow it down enough so that the rocket enters the upper atmosphere to slow down enough to get it back to earth. The problem here is that they want to use as little fuel as possible. But if they use too little fuel, the rocket won't slow down enough to fall back to earth the first time hitting the atmosphere, and instead go back into space - to fall down a little later, and probably not where they want it to fall down. The \"party balloon\" basically acts like a parachute. Space X said that it would increase its drag by \"two orders of magnitude\", meaning about 100 times as much. That would allow it to brake much harder and therefore enter the atmosphere at a much higher speed without going back to space - therefore saving fuel in the process. I don't know what exactly he means with a bouncy house though. If you want a more detailed explanation, I recommend waiting until [Scott Manley]( URL_0 ) makes a video about it. He usually explains what SpaceX is up to, and has a lot of videos about orbital mechanics that explain those things much better than I could.",
"Could you post where that quote came from? Thanks"
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8co7nc | how CGI gets implemented on to film for movies. | Technology | explainlikeimfive | {
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"There are a lot of kinds of CGI. Matte Paintings - are CGI backgrounds. You want to film inside a giant spaceship, and you can't afford a giant-spaceship-set? You build a set for the level of the spaceship that the actors walk around on and use CGI for the rest. This technique is at least as old as color film. Match Move - are CGI \"actors\". You get a person to dress up in a special leotard with dots at the center of every joint. Then you film them, like another actor. Then in CGI you replace each frame of the character with a matching size and orientation CGI character. CGI is a post filming process, you have the film, and you're using digital techniques to scan each frame, modify it with the CGI effects (sometimes 20 effects per frame). You digitally print the answer on movie film and send that to theaters (unless it's a digital theater, where they play the digital version directly)."
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8cqghu | how is bios installed on a motherboard? | Technology | explainlikeimfive | {
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"There are special memory chips on the motherboard that contain the BIOS. In ancient times, these were actual ROMs, read-only memory chips. That's too hard to maintain, so today most mobos use flash memory, like in a USB drive or camera card, to store the BIOS. That way you can do a firmware update with a special program rather than screwdrivers.",
"There is a chip that contains the BIOS, similar to a ROM. It is connected to the board. Sometimes a board can contain more than one BIOS.",
"How is it physically installed? Well at the factory they hook it up to a computer that loads it onto the motherboard, Im not sure how they do it now but back in the day they used to do it through the keyboard port. Once loaded it was stored on a chip like flash memory that you can carry on your keychain but physically attached to the board. Maybe someone can answer how they do it now, I assume they do it via the USB ports now."
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8cqgib | How do multiplayer online games play at the same speed? | To clarify, how do games like Overwatch, Fortnight, every MMO ever, etc... get all their players to interact in real time without lag? If I watch news broadcasters talking to field agents 10 minutes away there's a three second delay, but I can hitscan a man in Brazil while a man in Vancouver talks to me on mic with no noticeable delay. I'm sure there's some really cool computer science going on here and I'd love to understand it. | Technology | explainlikeimfive | {
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"So your internet data packets travel roughly 30% of the speed of light. That means, roughly 100,000 kilometers per second. So if you want to have ping of less than 20 ms, that is, 0.02 seconds, route from you to the server and back needs to be less than 0.02s * 100,000km/s = 2,000km. So if you live within 1000km of the server, you can achieve ping of 20ms, at least, in theory. There are some extra troubles here. Server can't respond to you instantly, it takes some time to figure out what kind of response you want. Also you have some processing to do on your end as well, drawing a single frame takes about 10 milliseconds from your gpu, and also non-gaming displays can have like 20ms delay between fame being ready to be shown on your computer, and the frame being actually shown. But anyhow, if you are within 1000km of the server, you should be seeing whatever server wants to show you within 0.1 seconds of you requesting this information. This to a human is almost unnoticeable delay. If the distance grows however, ping becomes more and more significant factor in causing delay, and at about 0.3s, it's very close to impossible to not notice this delay. So that's the basics of physics behind this. So how do games do this? A typical solution is that there is a central server, as before, which has something called \"tick rate\". Every tick, the server sends a packet describing what the server thinks the game world is like. Your computer then displays this world, and if you move or do something else in the game, your computer sends this data to server and once server receives your actions, it includes these in the next tick it composes. I know Valve games use tick rate of 64 ticks per second. Which is sort of nice, but if your actions have to go through server to be shown to you, this means there is distinct feeling of lack of control that can cause things like nausea if the delay between actions you make and these actions being shown on screen grows too large. So games typically cheat a bit. They try to guess what the server is thinking at the moment, and incorporate your own actions onto game world immediately. This means what you're being shown isn't actually the world as server tick describes it, but prediction like \"if the last tick was sent 15ms ago(taking network lag into account) and said the world looks like that, what would the game world look like now, 15ms later?\" So there are two closely linked game worlds your computer tries to keep in sync. Which usually works fine, but sometimes these worlds go off sync because of too much lag. This causes things like characters stuttering, warping around the map, things like that. But if everything works fine, your computer is able to make rather reasonable predictions about what's gonna happen next and these guesses and actual ticks stay in sync, so the game looks butter smooth to you even with about 100ms lag or something like that as game draws based on these predictions rather than waiting for server to confirm anything, and only after the fact it makes sure everything went as intended. If not, these sudden corrections are what cause warping, as your computer has to very fast fix position from predicted position to where the server tells that object actually is at. Lots of these kinds of corrections and everything just warps and stutters around your screen. With voice communications, lag can become much higher before you start noticing the delay. You probably would not notice 1 second delay on a voice chat that easily.",
"There's a lot of stuff happening, but most of it happens via a protocol called UDP UDP stands for User Datagram Protocol. You can think of it like a set of rules whose job is to get you packets of information very fast, but not always accurately. When you listen to music, watch youtube, or game, the protocol's job is to input your commands quickly, and produce results quickly. Sometimes, if you have a poor internet connection, you'll notice stuttering, lagging, or buffering. That's because there's something in the way, usually slow connection from getting all those packets of data reliably. so to move on to the next packet and keep up with \"real life\" timing, the data is dumped. And when the data is dumped, it's like nothing happened. Your \"shoot\" command was dumped, so you start lagging, or your Spotify song stopped playing and skipped to the next. Alternatively, the opposite protocol is TCP (Transmission Control Protocol). It's job is to make sure all your information arrives accurately, without respects to how long it takes. These protocols are good for things like downloads where every bit of information has to be in place in order to use the download (emails, offline videos, etc.) TCP is also used when there's a good connection to \"cache\" information to appear like it's a seamless connection when connection issues happen. This frequently happens with music apps. Or even Youtube videos.",
"Internet connections go via fiber optics, not satellite, so you can easily have a round trip in a fraction of a second, thousands of miles away.",
"With video games like these, there is a central server, ran by the games developers, and all players connect to the same server and so the lag is minimal, the only lag will be due to their latency and connecting to the central server. (Internet connections also differ from satellite which produces faster speeds) However with news reporters there is no central server, each are directly communicating to each other.",
"What helps with video game is that it transfers a lot less information than what is required for TV. Your video game sends and receive information about what happened in the game, like \"Player x shoot player y\". There can be a centralized server that calculates the results and sends back to the game what it should do. As for peer to peer, it is a bit of the same, but mostly every client assume the same calculation. It also helps that the infrastructure of the Internet is much better for data than what TV can do, most of the internet is through fiber, while most of TV is through satellite or copper wire. Edit: It is also good to note that, depending on the game, a lot of the calculations is done in your own game. This is why most hacks works; they rely upon the fact that the server doesn't really know what is going on. If there are no logic in place to check if what a hacker has done is realistic for the game, they can get away with a lot.",
"What a lot of people fail to add on is that game servers sometimes send data 1 tick behind instead of live. This allows everything to properly happen instead of not giving the server time to synchronize events, etc. 1 server time is a minuscule fraction of a second so it wont be noticeable to the player."
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8cqug0 | How does Powerline networking work? | Like the Powerline Adapter Starter Kit from Amazon, it claims to gain network connectivity through your house's power grid. How does this work and/or is this possible? | Technology | explainlikeimfive | {
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"Because this is ELI5, I want to make a minor clarification: those kits can use your house's power lines to transmit your existing internet from one location to another. With the paired endpoints, your can think of your existing electrical lines like a really long network cable. You don't GAIN any internet access simply by buying that kit. (You'll still need to pay for your ISP's service.)",
"Yep. I use a set to shoot my internet upstairs to a old WD wired-only live stream box. They work great in most cases with some caveats. The 120 volt AC stuff going through your house's power grid is a nice 60 Hz (or 50Hz if you're outside of North America) sine wave. All these things do is piggyback a small high frequency wave on top of that. The recipient box just has < blah blah boring electronics junk > that filters out or ignores the 60 Hz power signals and leaves them with the higher frequency signals which represent the digital stuff. As I said they work great, you just have to be aware that if there's any power line filtering between point A and B (like a UPS, a power conditioning AV power bar, or I'm guessing a PowerWall or something similar) will filter out your powerline ethernet signal. But most of us don't have anything like that _within_ our house, so it will probably work. The adapters will usually have some companion software that will test for that and/or basic connectivity between the two, as well as let you setup some basic security etc.",
"Others have already explained how they work technically, but I'd like to point out you've got a good risk that you're not going to get your full speed from them. It works fine for something like a TV or music player but if you want to max out your gigabit line you should run a proper cable.",
"Think about a really slow tune, which represents your power. Now, if you just overlay a Morse code(your internet), you can distiquish both, even if they're played simultaneously. Both are forms of waves and don't interfere each other, or at least not that much."
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8crari | Why are adult websites so infested with viruses and adware? | Technology | explainlikeimfive | {
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"Viruses lurk in lots of ads that tempt or trick you into clicking through. Porn is a category like this, where the user isn't thinking clearly and might eagerly click on whatever link promises XXXExactlyYourFetishHD. Your mom clicks anything that looks like a coupon for something she wants. Teenagers download NewSongByBeyonce.exe without realizing it's not an .mp3 file. Children click on anything colorful. Your grandmother clicks the big \"DOWNLOAD\" button without realizing it's an ad. Everyone is interested in seeing whatever gets them going sexually. Edit: spelling.",
"They really aren't though... the big name websites have fully fledged web security departments. Your more likely to get a virus from a small church's website... happy browsing.",
"Pornography has social stigma against it which means that the most well known and legitimate brands usually prefer not to advertise next to such content. Tide for example doesn't want their ads next to a bukkake video despite the obvious applicability. The result is that porn advertising space cannot be sold for as high a price and the providers cannot be as picky about those they sell to. Untrustworthy resellers that don't properly screen their ads can let some bad stuff slip in."
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8crftv | How is lighting (specifically from sources such as street lamps, torches etc) achieved in games. | I was wondering what type of mechanics go behind dynamic lighting in video games, specifically those of lamp posts, torches, sconces. Is there a difference between how it's handled in different game engines? How does one achieve different brightness at different distances, as well as how the lighting effects different materials. Lighting is one of those things that has fascinated me ever since the days of messing around in the Technology Test in Serious Sam The Second Encounter. | Technology | explainlikeimfive | {
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"Lighting is one of the larger tasks of game engines. You start off with an unlit mesh. You add a light source. The engine determines all the things that are affected by the light, taking into account objects that may be in the way. When the light hits a surface, it calculates the result, taking the intensity, color, and distance of the light, the color of the texture, as well as things like bump maps to simulate physical texture. That face of the mesh is now illuminated, allowing the player camera to see it. And yes, different game engines handle this problem differently. Old game engines would only do static analysis, calculating environmental light sources but not allowing dynamic changes. As technology improved, engines did as well, allowing for better lighting, shadows, and texture manipulation. Going beyond games, lighting in computer-animated movies allows light to bounce off material, refract, or allows for rules governing translucency. But this kind of thing currently can't be done in real time, thus why a CG movie looks a lot different than a video game.",
"There's quite a few types of lighting, but it sounds like you want lighting from a point source. 3D models are made of polygons. Think of those diamond commercials where you get a close up of the flat cut faces, those are like polygons on a model. Every polygon has a direction vector made of 3 numbers, called the \"normal\". It's the same thing as in physics, just the direction perpendicular to a surface, pointing outwards. Direction vectors in graphics all lie on a unit sphere, a sphere of radius 1 (you may have heard of a unit circle from trigonometry, it's a similar concept). The 3 numbers of a direction vector are the *x*, *y*, and *z* values of a point from the unit sphere. So if you start from some position and move to the end of a direction vector from that position, you will be 1 unit from your original position. If you have a polygon laying flat on the ground facing up, the normal is (0, 1, 0), the very top of the unit sphere. If you rotate it a bit around the *x* axis, the *z* and *y* would start to increase or decrease depending on which way you rotated it, but the length of the direction vector will remain 1. So if you have a 3D model in a computer, it's made of a bunch of points connected by lines to form polygons, each of which has a 1 unit long normal pointing outwards. If you rendered the model and drew all the normals from the center of each polygon, it would look like a porcupine. To light up the polygons, you need a light position. Then, you go along to each polygon and increase the color values of its textels (texture pixels) depending on how close its normal is to \"towards the light\". To get the direction towards a point, you calculate like so: Towards Light = (Light Position - Your Position) Then, you get the length of that vector with the Pythagorean theorem, and divide the vector by the length of itself to create a unit vector. Now, taking into account how close the polygon's normal is to \"towards light\", how close its position is to the light source, and how bright the light is, you can increase/decrease the RGB values of that polygon's textels. RGB is just 3 numbers from 0-1, (*red*, *green*, *blue*), with all 0s being black and all 1s being white, so polygons of identical color but facing different directions relative to the light will end up with different RGB values greater or less than their original values. This is close to what actually happens, but pretty much everything in graphics is done with matrices, which are big blocks of numbers that are easy for GPUs to work with, and there are many different lighting methods and algorithms. The process I explained here wouldn't give you shadows from other objects, for example. You also wouldn't get diffuse lighting from nearby objects. (a bright red metal wall makes everything around it slightly red, etc) There's also a slightly better looking lighting algorithm which lights polygons based on the points of the model. You give each point of the model a normal by taking the average of the normals of each polygon the point is a part of, then light those polygons based on how close that normal is to towards the light.",
"Yes, it's different between games. Modern hardware (GPUs) include ultra-specialized circuits sometimes called \"shaders\". The idea is to figure out how brightly (and what color) a surface glows based on the angle light hits it, the color of the light, the color of the surface, etc. This can be *super* efficient, partly because they're doing the same operation over and over, and don't need new instructions, just new numbers to crunch. This hardware might not even have the **ability** to receive instructions, it just does one thing very efficiently. Raytracing is a technology that follows light as it travels, and accounts for light hitting one object then bouncing to another... also, if a surface isn't shiny it might not produce a perfect reflection, but light may come off it in some general direction. Raytracing is good at figuring these sorts of details out, and takes a lot more computational power as well. There are many points between these techniques that trade appearance for efficiency. One example would be to assess objects which are illuminated, and treat them as light sources that in turn illuminate other objects. The actual calculations how bright everything looks may be very simple in this example, but it would produce a higher degree of realism."
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8csse6 | Why do SSDs have a read/write limit? What causes them to stop functioning after a certain number of read/write cycles? | Technology | explainlikeimfive | {
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"SSDs can be read as many times as you want, but they have a limited number of write/erase cycles SSDs are made using Flash memory which is constructed using floating gate transistors. On a normal FET transistor there is a channel with a thin insulator on top and a gate on top of that, the behavior of the transistor is controlled by the gate. On floating gate transistors there is the channel with a thin insulator, a gate, *another* thin insulator, and *another* gate. The gate in the middle isn't wired to anything and is electrically \"floating\" The bits are stored by charging and discharging this \"floating\" gate, but it has insulators on both sides of it. The only way to get charges on or off of the floating gate is to blast them through the insulators. This harms the insulator and it breaks down a bit, but you can do this for a few thousand cycles before it breaks down enough to start misbehaving To read the memory, you turn on the correct non-floating gates and can see if a line is pulled low or not, that gives you the status of each bit. This doesn't involve blasting charges through insulators so you can do this as many times as you want, it is also generally a fair bit quicker than writing"
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8cuaex | Why is it that there are 2 enter keys, 2 shift keys, 2 alt keys, etc. But only one tab and enter key on a keyboard? | Technology | explainlikeimfive | {
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"It's all about typing efficiently. The two enter keys exist one for letters and one for numbers, in case you need to hit enter after doing some calculations with numbers. The two shift keys (and two Alt keys) exist because you hold shift and type a letter at the same time. When you need to type a capital letter P, you can use your left hand for the shift key and use your right hand for the P. When you need to type a capital letter S, you use the right hand for the shift key. This prevents you from having to move one hand all the way to the other half of the keyboard. (Same goes for Alt keys.) You never have to hit Tab and a letter at the same time. Having only one on the left side is fine, because you never have to awkwardly type Tab **and** S **at the same time**."
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8cuywg | How can investigators find incriminating e-mails? | I've been following the news for awhile and from the beginning of elections to this day lots of people have been accused of various thnigs because of e-mails. How do people get these e-mails when they can be deleted? While some might have been thought fine how can some obviously incriminating e-mails have been left to be found? Is there some mechanism that saves every e-mail a person recieves or these people just don't know how to delete e-mails? I'm very confused. | Technology | explainlikeimfive | {
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"Well, first of all, people are not as keen on deleting email as you may think. Personally, I have every single one of mine since 1997. And, really, not everyone is comfortable enough around technology to understand that an email that is moved to the trash folder will stay there for a while before being deleted. Added to that, the server that stores the incoming mail might be set up to retain deleted email for a while. Because it's easier to restore email a client deleted if it's actually stored away somewhere for a short while. Some government agencies and some companies that find this to be useful have a mail system parallel to the one the users have access to, where incoming email is stored indefinitely. (just to name one example. I live in Sweden. Tax funded entities are forced by law to store all documents going on and out for a pretty long time. This includes email. If they have received it or sent it, they are forced by law to have a copy. That copy is also available at the request of any member of the public.) To ensure that there is always a paper trail that can be followed later. There is also a chance that previously deleted email are available on a computer that the user logged on to once in the past, because that is kind of how Windows handles user profiles. Added to that, a file on a computer is not necessarily gone just because it is deleted. If can be partially gone. Or hard to distinguish from garbage. Or possible to restore because the physical hard drive retains \"hints\" of data that has been on it, that can be checked with special equipment later, in an attempt to find something that was once there. A server for email is one of the most important pieces of equipment the company has. Without it, they will have loss of income and be totally drained on their productivity. The email server is so dan important that it's well backed up. One way or another, the data is often stored in more than one facility. Or backed up onto magnetic tape. Or any other scheme that ensures that even if the server is literally on fire, at the very least the data is still there and can be restored. Backing up data to tape is a time-consuming business, so to make it happen in the first place the backup system often has a computer that stores the backup mid-way to the tape machine. By looking at that computer, you can get a lot of hints on what has been on the master system in the past. Often you need to use a lot of tapes, so the tapes are handled by a robot that automatically switches tapes. And since tapes are a physical media, it makes sense to even out the wear and tear of the physical tapes. In other words, parts of a backup that is a month old might sit on a tape in the robot that the robot has deemed unfit, and marked for replacement. It will never be overwritten again, because the robot rightfully believes that the tape is giving up. That is the ways I can think of right now to find email at a specific organisation. But, you know. Email always has a sender and a recipient. Chances are that it was outbound. Or came in from the outside. This means that you can do this exact audit again at a totally different organisation and perhaps get a better result.",
"E-mails are sent through servers that can retain copies of e-mails. Also when you delete any file, they're not gone they're just overwritten by new data and can be recovered unless you took measures to really erase them (low level format of your HD or using a special app)."
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8cvbsh | Why were transits systems built much faster and more reliable in Europe than in Canada? | Technology | explainlikeimfive | {
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"Cities(and thus dense centre's of population) are much farther away in Canada than they are in Europe. It's much easier to build a good transit network to get 500, 000 people where they need to go, when they only need to go a shorter distance. This can easily be seen in canadian geography as our major cities are quite far away from each other (excluding the GTA). Even Calgary to Edmonton is a good 3 hours drive away, let alone going to Vancouver or Saskatoon or Regina. In Europe, because the cities are much closer together, you can spend more on the quality of the transit networks, simply because you do not have to make such a large quantity of them."
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8cxbqo | Why can't person A hear themselves during a phone call when person B has them on speaker phone? | Technology | explainlikeimfive | {
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"Most phones have sound processing functions. One function is where they turn off the microphone during times when sound is coming from the speaker during calls. You can notice this when you are talking to someone and there is wind on the other end - sometimes the sound will cut in and you can hear the wind on their end. But the system is dynamic, meaning that it attempts to figure out what sounds it should be allowing to pass while blocking others. There is a lot of programming that goes into this process, so there is a lot to go wrong with it as well. There is also a function that processes the sounds it is amplifying. This function recognizes sounds that it recently amplified through the speaker and attempts to ignore them by filtering them out of the microphone input. This is based on my knowledge of electronics (Electrical Engineer) and observation of how the phones act when in certain situations."
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8cxl1o | How videogames recreate water physics? | Technology | explainlikeimfive | {
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"Mostly poorly. The best approaches use Macklin's [Position Based Fluid algorithm] ( URL_0 ). It's computationally expensive, with thousands of splats needed in an area where non-water is handled with a few polygons."
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8cz6b4 | How does the calculator know 2+2=4? | Technology | explainlikeimfive | {
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"ELIaMOM: You use a fulladder. It actually adds the bits up: \\ 1 0 = 2 in binary \\ 1 0 = 2 in binary \\ 1 0 0 = 4 in binary 10+10=00, carry the one, you get 100. For more complicated calculations it would have look-up tables, just as you probably know the small multiplication table. ELI5: Does your daughter know what a counting frame is? Because claiming that the calculator has a sort of counting frame inside it based on electrical charges rather than small marbles is not completely dishonest."
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8cz7ne | Why does Netflix streams HD videos so much better than other video streaming websites? | Technology | explainlikeimfive | {
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"NetFlix hosts caching servers inside major ISP's networks. This means that if what you're watching is popular, it just has to travel the last mile to get to you, instead of hopping from network to network first, causing latency and lower quality due to bottlenecks.",
"So basically it's two things: The first is how they get the videos to you - Netflix has massive global \"Content Delivery Network (CDN)\", a huge network of servers which host all the movies and TV shows. Basically when you go to play a video on Netflix, the \"closest\" server to you is selected for you to stream from. Because Netflix is now so big, they've been able strike deals with ISPs (the companies who you pay to get internet) to be able to store their movies and TV shows on servers directly inside your providers network. No need to stream across large sections of busy, contested public internet. The second is what they do to the videos before they stream them - Basically because Netflix is big enough they can afford a great research and development team which has created ways to process the Netflix library so that it's smaller and easier to stream to you while being good quality. In fact, they now claim that you only need a ~200Kbps connection to stream at an enjoyable quality. While Amazon can also compete with Netflix in terms of ease of streaming (I find, anyway), most other services simply do not have the resources/motivation to create as good an experience. Youtube is a notable exception, however, because although Alphabet (Youtube's parent company) has tremendous resources, Youtube's video library is *HUGE* and growing everyday. To be able to host and process all that as well as they do at the moment is something of a miracle, but with current technology, there's no way you could get the Netflix experience on Youtube. Edit: Just to clarify, when you actually visit the netflix website/app/etc, the interface and the catalogue of content (titles, artwork, cast, etc.) is served to you from an Amazon AWS datacentre. When you actually click on a video, the website/app/etc tells your device to go and fetch the content from one of the servers - or Open Connect Appliances (OCAs) - inside or \"near\" your ISP. Essentially, everything before you hit \"play\" comes from an Amazon server, everything after comes from Netflix's CDN called \"Open Connect\".",
"The control plane (what's needed before a video starts playing) is hosted on Amazon (AWS). From there, the closest content server to you (or best for another reason) is used to get the video content to you, in order of preference: - a Netflix Open Connect appliance co-located at your ISP - through a PNI (Private Network Interconnect) between Netflix and your ISP - through a public peering point (IX) The reason it's so good is they've spent a lot to put their content everywhere they can and to have fallbacks if, for instance, the local appliance at your ISP is too busy.",
"The simplest answer (which duplicates a lot of answers here) Netflix does not send a copy of Stranger Things to you from it's HQ in California. Instead, Netflix stores a copy of it on a computer *in every city* So they only have to send the video ten miles, instead of a few thousand miles from California. Not only does a short trip take less time, there aren't as many accidents and traffic jams to slow it down along the way",
"This video does a great job at explaining this. It's Techquickie by LinusTechTips URL_0",
"This URL_0 and a load of propitiatory software to keep things scaled and smooth.",
"Netflix and many other major Internet content distributors use CDN (Content Delivery Network) infrastructure to cache content at consumer ISP facilities. This allows them to feed network streams to houses and businesses without the data having to cross from one network provider to another and without having to cross backbone providers. Think of it in these terms: If you wanted to mail a care-package to your friend across country, you could collect and package the items and take them to your local Post Office, where it will travel to the local sorting facility, the regional sorting facility and then be shipped as cargo across the country to your friend's regional > local sorting facilities. From there, it is placed on a carrier route and delivered to your friend. This carrier route is the last mile. Wouldn't it be so much faster if you could order a pre-made care package from the Post Office and have them enter it into a local carrier route today or tomorrow? CDN's do that. You request something (small amount of data in the request) to be delivered to you. That something (large amount of data) can travel hundreds or thousands of miles or it can be accessed from a local ISP cache across town. Local ISPs (AKA \"Last mile delivery\"- same for USPS) have much more capacity to transmit data from neighborhood to neighborhood than it requires to transmit from one data warehouse to ALL neighborhoods. You have a wicked fast connection between all the computers inside your house (LAN) your connection to your ISP (WAN) is MUCH slower. The connection of all of your neighbors back to the ISPs local node is the aggregate capacity of your ISP. Instead of everyone in your region trying to get data passing over all these networks, this archive data (it's not changing once it's produced) can be stored all over town on cheap hard drives. When you attempt to view this content, instead of going back to Netflix' main data warehouse across the country, you just get it from one of those nearby archives- CDN. This also has an enormous effect on total national throughput since most people are pulling the same 100,000 episodes of TV and movies around dinner time. By caching locally, live data has less competition for bandwidth and the backbone networks are not pressed as hard. Have you ever gotten the message \"All circuits are busy. Try your call at another time.\" when calling someone during an emergency? It's because the POTS telephone system is switched instead of packetized, meaning that there are a finite number of wires that go into/out of each phone exchange. Without CDNs Netflix would do this to everyone's Internet every night as the packets all queued up to travel to their destinations. Unlike switched networks, TCP/IP networks transfer data in a guaranteed method. If a packet doesn't arrive in time, the recipient requests it be re-sent. (UDP/stream packets don't work this way but do provide some quality assurances which you notice when the stream suddenly improves or degrades because the application is telling the server to send a small file-size version of the video). Each Netflix video is actually saved in several quality formats so that the application can select the best available stream in real time. This means you get the best video experience available at the time you're requesting it and without requiring the dreaded buffering stops.",
"They also have a AI algorithm to improve streaming in the best possible quality regardless if the quality of connection"
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8d3y8j | What's the difference between a Hub, Repeater, Bridge and Switch? | Technology | explainlikeimfive | {
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"* Hubs are simple devices that send every packet received on any port to all ports. * Switches learn which devices are on which ports, and packets addressed to a known device are sent only to that device's port. * Repeaters are hubs with only two ports. * Bridges are switches with only two ports."
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8d4tg9 | How come diesel engine have been praised in the past and now suddenly everyone seems to be against it? | Technology | explainlikeimfive | {
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"Different type of fuel and compression result in different products - diesels run in high compression and hot so they burn their fuel thoroughly, however it also causes atmospheric nitrogen to react with atmospheric oxygen, producing toxic nitrogen oxides. The recent diesel scandal was companies cheating with the engine computer to reduce nitrogen oxide output when it was detecting it's in emissions test. Petrol engines run less hot, so their exhaust contains some unburnt hydrocarbons and more carbon monoxide but also less nitrogen oxides.",
"Like many things, the popularity of diesel-fueled passager cars has gone back and forth over the years, particularly in the US. In the 1970s, gasoline prices shot up and diesel was significantly less expensive, so diesel cars became more popular. However, they made poor passenger vehicles, especially the American ones, and their emissions were dirty and sooty. They were largely abandoned by the 1980s as the price gap between the fuels shrank. By the 2000s, cleaner diesel fuels and turbo diesel technologies overcame the drawbacks, and their popularity returned due to their improved fuel efficiency over gasoline. But earler this decade, VW got caught programming their diesel engines to cheat on emissions tests, result in a massive settlement that took many of their cars off the road. Between this, and the general sentiment against fossil fuels, diesel's reputation has suffered. Still, the technology itself is fine, generally cleaner and more efficient than gasoline. A turbo diesel mid-sized vehicle can get better mileage than a Prius, especially on the highway.",
"Back in the 70's some people bought diesels because diesel fuel was much cheaper than standard gas. Remember the big kerfuffle a few years back around VW cheating the emissions tests? Inexplicably to anyone who's seen the exhaust of a diesel truck, diesel cars were being accepted as environmentally friendly. That all ended when the lie was exposed, and VW isn't the only company that was cheating.",
"Gasoline/petrol engines are less fuel efficient and give off more carbon dioxide, which means they are worse for the environment from a general/global warming perspective. Diesel engines give off more nitrous oxide, which is worse for human health (particularly in the immediate vicinity of the cars), but are more fuel efficient so better for the overall environment. For many years, diesel cars were seen as cheaper to run (as they had better fuel economy) but cruder (louder and courser engines), which put off many buyers. In recent years, Diesel engine technology improved and the engines became more refined and pleasant to live with. Manufacturers also claimed that the engines were managing to significantly reduce the nitrous oxide emissions to much lower levels. This is important because we are increasingly aware of the high levels of nitrous oxides in areas (such as neighbourhoods) near roads with many diesel vehicles, and of how damaging this can be for human health. The recent VW scandal came about because it was found that VW had cheated in the testing and in reality the cars were releasing much higher nitrous oxide levels in the real world than they were in the testing. So while the Diesel engines were still more fuel efficient than gasoline, they were releasing levels of nitrous oxides which were unacceptably high by modern standards.",
"They were praised initially because diesel vehicles typically achieved much greater fuel economy numbers, and diesel is easier to make than gasoline. Now everyone is scared of them because of cheatin' VW's.",
"It's essentially the sheer amount of nitrogen oxide emissions they produce due to much higher compression in the cylinders. They lead to increased smog and repository issues, and there seems to be no economical way to remove all the NOx without sacrificing power and fuel economy."
],
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8d67pn | How do gift cards generate profit? | Technology | explainlikeimfive | {
"a_id": [
"dxkk28z"
],
"text": [
"I'll add my 2 cents. I work in retail and for my company, the actual selling of giftcards isn't what generates the profit. When someone buys you a gift card for my brand we know that at some point in the future you will buy something from us. Many times people will attempt to use the whole gift card which means they go over and spend money on top of that. TL;DR - gift cards are guaranteed future sales."
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4
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8d7mri | [technology]: Bump Stocks | Technology | explainlikeimfive | {
"a_id": [
"dxkw3wq"
],
"text": [
"A bump stock makes it possible for a semi-automatic rifle, which does only one pew per pull of the trigger no matter what, to pull the trigger faster than your finger can by itself, using your finger plus the recoil of the rifle to \"reset\" the trigger much faster than you can do it by yourself. A bump stock is not even a necessary device to be able to do this. (@seealso YouTube) Oh, and why is America going ape over them? That leads directly into pro-gun/anti-gun debate and mud-slinging, so I won't go there. There's enough divisiveness in the world as it is."
],
"score": [
4
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|
8d7z1j | How was the music video for "Virtual Insanity" by Jamiroquai made? | Technology | explainlikeimfive | {
"a_id": [
"dxkzjbx"
],
"text": [
"It was surprisingly low tech \\- basically they built the floor on wheels and would move the floor around with Jamiroquai dancing on it This video: [ URL_0 ]( URL_0 ) shows the technique they used but for a different project \\(a beer ad\\) Edit: Turns out they moved the walls around instead of the floor"
],
"score": [
4
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"text_urls": [
[
"https://www.youtube.com/watch?v=4zOBBZbyrIU"
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|
8d93ho | What is the point of a touch free soap dispenser? If the soap was somewhat decent it would be pointless or am I missing something? | Technology | explainlikeimfive | {
"a_id": [
"dxl8lcc",
"dxl920d"
],
"text": [
"Soap isn't magic. If you scoop up some poop in your hands and then rub in some soap, you still have soapy poop in your hands.",
"Soap does not really ''KILL'' 99.9% of germs like often advertised. Soap works in a way that it helps oil particles in which germs are usually in to join up with water molecules so that they can be easily washed away. This means that when you wash your hands, you are simply rinsing bacteria off of your hands, but if you do not wash or DRY your hands properly, you might as well keep those germs on your hands. Imagine touching a soap dispenser after someone with an infectious disease and not washing / drying your hands properly. It is the incorrect etiquette of soap usage that makes people sick when touching an infected surface. Not touching it greatly reduces the chances of fucking up your cleaning session and having to regret it later."
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5,
4
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|
8d9gv4 | what does polishing shoes actually do? | Technology | explainlikeimfive | {
"a_id": [
"dxlcien"
],
"text": [
"I feel like I saw this question a while ago I'm confused now. There are leather conditioners that keep leathers supple and prevent them from peeling and cracking. You can gently remove substances that are harmful to the integrity of the leather like salt and you can clean the dirt off It's very important to do this before polishing You can take a special brush or a clean rag and apply the conditioner Then you can apply a polish that matches the tone of the leather and buff out light scratches and marks and even out irregularities in color caused by fading and staining and restore some of the richness of color. A good cleaning and polishing ritual can extend the life of the garment and keep it in good condition for longer."
],
"score": [
3
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8da0xd | How did the litre (volume) come to be? In other words if we had to start from the dark ages again, how could one replicate the volume measurement of 1 Litre? | Technology | explainlikeimfive | {
"a_id": [
"dxlghag",
"dxlgowe",
"dxlghek",
"dxm1g19",
"dxm5xc3"
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"text": [
"The metric system is based on the distance from the North Pole to the equator, on a line passing through Paris. This distance, divided by 10,000,000 equals one metre. One metre divided by 1000 equals one millimetre. One cubic millimetre of water equals 1 millilitre. 1000 millilitres equals one litre.",
"The Metric System has a few units of measurement that are [the \"base\" units]( URL_0 ), with all the other units deriving from them. If you look at the list, they decided what a metre was, then they took 1 litre to be 1/1000 of a cubic metre of water, and 1 kilogram to be the weight of said litre of water. 1 degree Celsius (and Kelvin) is based on the range of water freezing at 0 degrees and boiling at 100 degrees. So, for the metric system, all of the units are derived from the basic units, and various properties of water on Earth (in standard Earth gravity, etc.)",
"The litre is baced on the weight of a cubic decimeter (0.001m^3 or 1000cm^3 ) of water, and was was introduced in France in 1795 as one of the new \"republican units of measurement\". From this weight, the kilogram was also derived",
"The units are arbitrary. The benefit of the metric system is not in the length of a metre (etc), its in that the system is based on powers of ten, making arithmetic much simpler between different units. A kilometre is 1000 metres. *Historically* the metric system had its roots in revolutionary France. There were a few base units that all other units are derived from. The metre is based on the earth arc. The litre is a unit of volume. Volume is just length in 3d, so the litre is based of the metre (10 centimetres cubed to be exact). Weight was traditionally tied to size of the metre as well, defined by a unit of water in a particular unit of volume. Temperature in Celsius/centigrade is based of the freezing and boiling points of water. You kind of get the picture, the units are tied together. You just start with some random unit of length or whatever and build up from there as much as possible. Modern SI has 7 base units from which all other units may be derived.",
"A litre is just a shorthand for a cubic decimeter (dm³). It is the volume of 10cm cubed. Decimeter and centimeter are based on 1/10 and 1/100 of a meter, so the litre is based on the meter. The meter was invented during the French revolution (quite a bit after the dark ages). It was orginally based on the circumference of the earth. (1/40,000,000 of the earths Polar circumference.) Since the earth is funny shaped and measuring long distances is not easy we eventually came up with more accurate ways to define the meter. The current one is based on the speed of light and the length of a second which in turn is today defined by the number of time a cesium atom vibrates between energy states. If we ever fall back into the dark ages we probably won't be able to accurately measure the speed of light and the vibration of cesium atoms, so we will fall back on older less accurate definitions like the length of a day to define the second. Figuring out the polar circumference in the dark ages will not be very accurate either. Eratosthenes who lived 200BC was able to measure it with perhaps a 10% margin of error, not really a good way to define a unit for every day use. However we know a lot of other ways to define the meter based on other units who might be easier to preserve. If we retain the kilogram we could simply say that a liter of water at room temperature weighs about a kg. Or we could use the length of a pendulum with a certain period if we retain a good enough measure of the second (the length of the day should suffice) and if the gravity on earth does not change (we can hope that this is given). If a single physics textbook survives we should have enough ways to reproduce the length of a meter even in a low tech environment to keep us going. The new meter will not be 100% accurate, but as we claw ourselves back to civilizations the value should become more and more like the current one until we are back to counting cesium atom vibrations."
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"https://en.wikipedia.org/wiki/SI_base_unit"
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8dc2tx | Given the fragmented instant messaging market and the failure to create a standard protocol, why aren't there email clients that make using email more like instant messaging? | Technology | explainlikeimfive | {
"a_id": [
"dxm2jbc"
],
"text": [
"Huh? Email essentially already is instant messaging, if the user utilizes it in that way. You can get notifications that pop up on your computer that tell you that you just got an email, and it's essentially instance. Your phone can tell you that you just got an email, and it's essentially instant. I sometimes use email like that with my less Tech Savvy family members. I will have a 10 or 20 email long chain in only a few minutes, because we are just emailing back one or two sentences to each other. Today, I don't think there is an issue with email clients or technology. It's simply how the users utilize it. Also, instant messaging it's probably not as popular as it once was, since the Advent and popularity of phones and texting has taken over from that."
],
"score": [
5
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|
8de32z | Why does an electric kettle make that loud rumbling sound when its heating up the water? | Technology | explainlikeimfive | {
"a_id": [
"dxmczbl"
],
"text": [
"Cavitation. The electric element that heats the water heats it so fast that instantly boils. This boiling air then hits the slightly colder water above it, and cools and immediately collapses."
],
"score": [
3
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8deayq | What caused Bing to fail and Google to rise to popularity so much when they’re so similar? | Technology | explainlikeimfive | {
"a_id": [
"dxmebqu",
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"text": [
"Google was around before Bing, so it already had a better established user base (I guess before Bing there was MSN search, but... who used that?). The reality is that Google just has a better search algorithm that provides people with more relevant results, and it's simple to use. Bing is a little flashier and it tends to return less relevant results. There was a scandal where it was found out that Microsoft had copied Google's code for Bing, too, and that attracted some negative attention that certainly dissuaded users from using it. Finally, the fact that it's just not the default search engine in the browsers that most people are using (Firefox and its spin-offs and Chrome and its spin-offs). It's only the default on IE and Edge, which arguably have the smallest user bases online these days. So, people aren't going to want to navigate out of their way to a site that gives them worse service than the default search does.",
"google came first. Well... URL_0 had a search and has been around since the internet was still cooling from the big bang. but that was more in the old school vein of things like AOL, Yahoo, Ect. google got traction as a new search engine with a vastly superior algorithm (that gap has since all but evaporated, but the market share remains). gmail was big, made their users very sticky since it maintains their position in your bookmark bar no matter what."
],
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14,
3
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8dedvy | What exactly do Neural Networks in AlphaZero/LeelaChess do? | IIRC, the MCTS rollouts determine how advantageous each move is in a given position. So, if it's the MCTS coming up with the solutions, what is the purpose of implementing Neural Networks in the first place? How does it differ from an MCTS-only chess AI? | Technology | explainlikeimfive | {
"a_id": [
"dxmkcwa"
],
"text": [
"If you're going to do a Monte Carlo Tree Search, you want some way to assign probabilities to candidate moves. If you favor moves that are likely to be strong more over moves that are likely to be weak, you're going to do much better than if you pick moves uniformly at random. The neural network spits out a vector of moves when given a position with scores predicting their strength, which affects the probabilities that they are taken by the search."
],
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8dft23 | With web extensions, like the heavily-advertised "Honey" service, "automatically find[ing] and appl[ying] coupon codes at checkout with a single click," wouldn't this drive up prices at these websites? | Technology | explainlikeimfive | {
"a_id": [
"dxmrzmu"
],
"text": [
"What lost income? If anything, they may see increased income. Having easy to access coupons can encourage buyers to buy more, or buy stuff they weren't planning to originally buy. It also attracts buyers who weren't going to buy anything. New sales can make up for the discount provided by the coupon. Not to mention most of these coupon savings are minimal (like 10% off or free shipping) and if a product is sold at a high enough profit margin, the company is still making money."
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8dgilz | How does a telephone plug work with both a phone and a modem? Is it the same data being transferred or is there multiple types of data being passed and the device decides which one it needs? | Technology | explainlikeimfive | {
"a_id": [
"dxmx99h",
"dxmxjcn",
"dxn03hj"
],
"text": [
"A modem converts the analog signal coming over the phone line to a digital signal usable by for example, a computer. The same concept applies to all modems for example, a cable modem. It's an analog signal converted to digital.",
"If you mean an old 56kbit modem, then they can't be used at the same time as a phone. A DSL modem can be used with an analog phone call because the DSL signal uses frequencies which you can't hear. A filter is used to keep voice signals and equipment from interfering with the DSL.",
"MODEM is an acronym for Modulator/Demodulator. It converts analog signals into digital code so a computer can understand. And vice versa."
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8diq8h | Why do phone boot logos always seem so choppy when phones are capable of 60fps? | Technology | explainlikeimfive | {
"a_id": [
"dxng6se"
],
"text": [
"When a phone is just booting up, it is not able to access every part of the phone yet. Kind of like when you just wake up and can't solve a math problem. If it is \"capable\" of 60fps, that doesn't mean it will always operate that way."
],
"score": [
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|
8dj76f | Why does uninstalling apps off my phone use data? | Technology | explainlikeimfive | {
"a_id": [
"dxnk1wv"
],
"text": [
"Modern phone operating systems talk to a cloud service to keep track, remotely, of what apps are installed on the phone. This can help with troubleshooting later."
],
"score": [
4
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"text_urls": [
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|
8djqex | Why is it so hard to replace the IRS's aging computer systems? | I just heard an NPR story that said the IRS's computer system is the most antiquated in the federal goverment (it still uses assembly!) Why is so hard to replace it? | Technology | explainlikeimfive | {
"a_id": [
"dxnsbka",
"dxnp5ui"
],
"text": [
"This is a problem throughout the software industry. Banks, airlines, and hospitals all have legacy computer systems they just can't shut off for a week to put in a new one. Then short-term thinking sets in, and it is easier to to limp along for just one more year than it is to upgrade. But you do that for 15 years in a row, you basically wind up with shit stacked on top of shit, held together with duct tape of bailing wire. What's more, before the late 1990s, connectivity wasn't a big design consideration. Computers still talked to each other, but it was limited to simple data transmitted over low bandwidth connections, so mostly each system handled things itself. That meant each one could be a custom build job, tailored to what one customer thought they wanted, without any regard to what anyone else was doing. It would like every house running at different voltages with different sized electrical plugs. It would be fine within your house, but if you wanted to anything with your neighbor, it would be a big hassle. Here is a timeline of a typical legacy system: * 1985 - pay small software company $1M to write and deploy custom application for you on a mainframe computer * 1988 - new version of the mainframe OS comes out, software vendor says it will cost $100K and a week of downtime to update the software...decide system works fine as is, do nothing * 1990 - office starts using PCs, buy interface software and hardware that kind of sort of lets you run the application form a PC * 1993 - mainframe company announced end of life for your hardware, software vendor says it will cost $500K and two weeks of downtime to move to modern hardware...decide to pay hardware vendor extended support instead * 1996 - realize Y2K is coming, new software vendor says they can set you up with a new, better application for $2M and a three month transition period...spend $500K for old software vendor to hack together a solution * 2001 - mainframe support completely discontinued, pay $2M for new hardware with emulation software to pretend to be your crappy old hardware * 2005 - need to allow computers to securely communicate over the internet, spend $500K on middleware to translate between mainframe and internet...poorly * 2010 - new gov't regulations require changes to software, software vendor no longer in business, pay consulting firm $2M to try to reverse engineer software and make the necessary changes...poorly * 2012 - your webpage sucks, pay $1M for more middleware to allow your mainframe to talk to the internet * 2015 - new industry standard for data transfer emerges, pay consulting firm $2M to cobble together some more middleware And now it is 2018. Because you didn't want to spend $100K twenty years ago, you now have spent millions more on a Frankenstein's monster of a half dozen system from different eras trying to work together. What's more, no one actually knows how it actually works anymore, and you are reduced to primitive tribesman offering sacrifice to an inscrutable god, hoping you don't incur its anger. And if for-profit companies do things this badly, you can imagine how much worse government is about it. Source: Welcome to my world",
"Because of a combination of outdated customs made software, lack of funding, bureaucratic red tape for replacing \"fucntional\" machines, and the effort of data migration."
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8djqlu | How come smart phones can run intense games without a fan and still not burn the CPU, but a desktop computer can't even load the desktop for more than a few minutes without permanent damage? | Technology | explainlikeimfive | {
"a_id": [
"dxnoq16",
"dxnp0nu",
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],
"text": [
"The chips in the phone are specially designed to minimize power usage for common tasks. This isn't a priority in desktop PCs.",
"Comparing the workload generated by a mobile game to a PC game is like comparing a lit match to the sun. Even the design of their chips are significantly different, and ultimately a lower powered tool. In the late 90's when the first gigahertz CPU's hit the market they required serious coolant systems. Meanwhile my Raspberry Pi with a much simpler architecture runs at 1Ghz with nothing but a little aluminum heat sink. To a certain extent you're asking \"why does the VW Beetle work with just air cooling, but a race car requires a coolant system straight out of NASA.",
"95 Watts for a current gen desktop processor vs 4ish for ARM processors amongst other things. Phone os and games are much less demanding plus it is a different instruction set which help also. I like the car engine analogy."
],
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24,
6
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8dl8wz | how are lasers used to measure distance so accurately, and why can it also track movement i.e. with a PC mouse? | Technology | explainlikeimfive | {
"a_id": [
"dxo1yq3"
],
"text": [
"By firing a laser bean at something and measuring how long it takes to reflect and fly back. (Distance = (c*time) /2) ---- Laser mice works the same as other optical mice, they just use laser instead of a regular LED. They take pictures (thousands per second) of the illuminated (by laser) surface under the mouse and determine how are each pictures different and how the mouse moved. Laser can go deeper in the materials and thus sense smaller changes in surface. Thought even optical mice are pretty good nowadays and that's why you don't see the laser mice craze much anymore."
],
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8dm4a9 | What is unique about Playstation 2 disks that prevents us from booting burned ISOs? | I know that you need swap magic or some kind of memory card hack to boot homebrew stuff, but I don't understand why. I'm guessing PS2 disks have a proprietary physical format that differentiates them from regular CDs, but I can't seem to find any information on it. | Technology | explainlikeimfive | {
"a_id": [
"dxo76g0",
"dxodpdw"
],
"text": [
"[This]( URL_0 ) is how PS1 did it. I assume PS2 had a similar system in place",
"The disks have an error correcting system built in to the lowest level, meaning that sections of the disk can be marked as unreadable. Because it's a low-level function, disk-copying programs won't copy the errors, they'll \"fix\" themas they copy. The playstation just looks for a predetermined pattern of these errors and refuses to run if it doesn't find them - the mod chip that you could solder in to the motherboard bypassed this check, allowing you to use copied disks."
],
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"https://youtu.be/XUwSOfQ1D3c"
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8dszxi | Why do circuit breakers flip? | Technology | explainlikeimfive | {
"a_id": [
"dxprys0",
"dxpv7of"
],
"text": [
"Essentially, it's a spring / clamp that trips at a given temperature or magnetic strength. As the amperage increases, the amount of the heat generated by the increase to resistance and/or the increased electromagnetic field causes the clamp to releases to trip the breaker.",
"Circuit breakers are over-current protection devices. They protect against the creation of dangerous electrical circuits. 1.) They protect against wiring faults in which the hot wire is shorted directly to another out-of-phase hot wire, a neutral wire, or a ground wire. When this occurs, the contact point will usually weld; the wires will then heat up until something melts and the circuit fails. Unfortunately, the wire insulation will melt long before the copper or aluminium conductor melts, creating electrical fires and potential future hazards. 2.) They protect against excessively large electrical loads. When current flows across a conductor, it causes the conductor to heat up. Most building wiring is sleeved in vinyl insulation which is rated to 90 degrees centigrade. If the receptacles, breaker, and wiring are all properly sized, the wire should not exceed 60 degrees centigrade (75 degrees in some applications). If the temperature gets too high, the insulation will melt and expose the bare conductor. Consider, for example, a toaster oven, air conditioner, and gaming PC all running on the same circuit. These devices have their own power cords and the current travelling into each is appropriate for that appliance. However, the current on the wire returning to the panel is the sum of all three loads at once. This could be bad. 3.) They protect against electrical faults in devices. Any device with a metal chassis will have a ground conductor connected to the chassis. If the device fails while it is powered on, the metal chassis may become energised. If someone were to touch it, they may get shocked. With a proper ground conductor and circuit breaker, the ground conductor will carry current from the chassis to the earth rather than the operator's body. The ground path is very low resistance, meaning that the current will be high enough to trip the breaker and cut power to the faulty device."
],
"score": [
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|
8du9bq | why it takes longer to search my windows computer for a file than to google something. | Technology | explainlikeimfive | {
"a_id": [
"dxq1sf5"
],
"text": [
"Indexing. Google has a huge, highly optimised database designed for the sole purpose of searching quickly. Even with indexing switched on, your computer doesn't have anywhere near as good a system. Speed. Your query to Google is dealt with by an extremely fast computer - many times as powerful as your home PC. Caching. Chances are that whatever you're searching, other people are also searching too. As a result Google has these results ready even faster. Your PC doesn't need to do this with search results, so searches from scratch each time."
],
"score": [
3
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"text_urls": [
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|
8dvy55 | What happens when you don't safely eject your USB? | Technology | explainlikeimfive | {
"a_id": [
"dxqd61s"
],
"text": [
"Data that was being accessed could be corrupted or deleted, making it unreadable for future use. When you \"safely eject\" the device, you're basically letting the computer stop all processes and make sure nothing is being accessed before you disconnect the device. If you just pull it, you have no idea if the data was being used or not."
],
"score": [
3
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|
8dwfw8 | How do hotel card readers work? | Technology | explainlikeimfive | {
"a_id": [
"dxqhgov"
],
"text": [
"The lock sends out a signal, using batteries in the lock. The card has a coil that captures that energy and uses it the power a circuit. The circuit powers a radio that sends a number programed into the card by the front desk. The lock has a radio receiver that opens the lock if it gets the right number."
],
"score": [
8
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8dws0b | why are amazons (or any company's) servers/scripts named with seemingly jibberish names like URL_0 (1)? | Technology | explainlikeimfive | {
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"dxqjspo"
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"text": [
"Typically this is done automatically as part of the build pipeline to facilitate caching. Next time a build is completed the bundled scripts/css will be combined in a file with a different name. Since it has a different name the browser won’t find it in cache and will pull down this new version from the server"
],
"score": [
3
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|
8dxd8e | How does a calculator know what addition/subtraction is? Likewise, how does a digital clock know exactly what a second/minute is? | Technology | explainlikeimfive | {
"a_id": [
"dxqouxc"
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"text": [
"digital clocks have a quartz crystal inside shaped like a tuning fork. When an electrical voltage is applied to it it vibrates at a certain frequency; conversely, when the crystal is deformed it creates a small current. These fluctuations in current are counted to see how much time has elapsed."
],
"score": [
4
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|
8dymi2 | How do they manage to fit a full video game on a disc? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Depends on the era, but generally speaking disc technology allowed for more storage than other forms of media at the time. Consider the original PlayStation. Cartridge based consoles of that era had games that were barely over a few megabytes, but ps1 discs could hold nearly 600 times as much data as a cartridge. Computers of the era had hard disks which were a few gigabytes at most, perhaps a dozen CDs worth of storage space. Of course, the same is perhaps true of now: a single layer Blu Ray disc holds 25 GB of data, twice that for dual layer. And for pennies per GB to manufacture compared to flash media. From a cost perspective, discs are the best way to distribute games, so devs will necessarily constrain their games to fit... usually. Multi disc games were a thing back in the day, and day one mandatory patches are not unheard of today. As for how they physically operate.... Uhh I dunno, lasers?"
],
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|
8e1a5t | Why can you get cell service in the hallway of the 7th floor of a 21-story building, but not in the elevator or basement? | Technology | explainlikeimfive | {
"a_id": [
"dxrmbha"
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"text": [
"Ahoy, fellow redditor. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do mobile phones lose reception when going up/down an elevator? ]( URL_2 ) ^(_10 comments_) 1. [Why does cellphone service cut out in an elevator, but works everywhere else in an enclosed building? ]( URL_3 ) ^(_4 comments_) 1. [ELI5: Why do cell phones not work in basements? ]( URL_0 ) ^(_3 comments_) 1. [ELI5: How we can receive signals from spacecraft hundreds of thousands miles away from Earth, but I can't get cell service in my basement? ]( URL_4 ) ^(_4 comments_) 1. [ELI5: How can wifi work so well on planes but every elevator is a time machine back to 1995? ]( URL_5 ) ^(_4 comments_) 1. [ELI5: why can't mobile data work inside an elevator? ]( URL_1 ) ^(_3 comments_)"
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"https://www.reddit.com/r/explainlikeimfive/comments/3it22m/eli5_why_do_cell_phones_not_work_in_basements/",
"https://www.reddit.com/r/explainlikeimfive/comments/6eug4z/eli5_why_cant_mobile_data_work_inside_an_elevator/",
"https://www.reddit.com/r/explainlikeimfive/comments/7pvkun/eli5_why_do_mobile_phones_lose_reception_when/",
"https://www.reddit.com/r/NoStupidQuestions/comments/7vov57/why_does_cellphone_service_cut_out_in_an_elevator/",
"https://www.reddit.com/r/explainlikeimfive/comments/1ladb4/eli5_how_we_can_receive_signals_from_spacecraft/",
"https://www.reddit.com/r/explainlikeimfive/comments/566f8b/eli5_how_can_wifi_work_so_well_on_planes_but/"
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8e2omo | Considering the predominance of the USA on the Internet, why are there so few .us websites? | Technology | explainlikeimfive | {
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"dxrw7yb",
"dxryoyp"
],
"text": [
"The United States is where internet was born, so they get to be .com whereas everyone else has to be .Country.",
"*Because* of the US' predominance on the internet. Remember that \"The Internet\" predates \"The World Wide Web\", and for many years was entirely non-commercial (commercial entities weren't allowed on the internet at all). The \"main\" toplevel domains (.com, .net, .org, .gov and .mil) were by default considered to belong to American entities. Add to that the fact that, by now, domain names are pretty much a free-for-all (you can purchase a domain name in virtually any toplevel domain you want, or even register *new* toplevel domains), and many entities prefer the \"global\" look of a .com."
],
"score": [
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|
8e2z4p | Why x,y (0,0) in computer world positioned on Top-Left instead of Bottom-Left like in mathematics? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Old TV sets would \"draw\" the image on the screen by drawing lines from left to right, starting at the top and going to the bottom. This was adopted for computer monitors, and then by programmers because it made it easier to have the ordering be consistent. As for why TV sets were made that way, it's probably just because many languages are written and read left-to-right, top-to-bottom. The people designing TVs weren't thinking about \"(0,0)\" and indexing the screen pixel-by-pixel using computer science or math conventions because there was no reason to at that time.",
"The first computers only printed out text (on actual paper) and later displayed text on monitors. And text is printed from top to bottom, so the y-coordinate for the character grid starts on top. I guess nobody wanted to have a different coordinate system when they introduced graphic modes.",
"It's not always top left, IBM OS/2 put it bottom left. The BPM image format was created by Microsoft around the time they were working on OS/2 with IBM. It stores the image data bottom up instead of top down like other image formats. Mac OS X also used a coordinate system bottom left, but I believe it was configurable. ( URL_0 ) Raymond Chen of Microsoft covers why it's usually top left: URL_1 The reason he gives is because that's the way the electron gun in a CRT scans, therefore, that's the way the video memory was laid out. It was the simplest way to do it at the time."
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"https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CocoaDrawingGuide/Transforms/Transforms.html",
"https://blogs.msdn.microsoft.com/oldnewthing/20101004-00/?p=12643"
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8e3vrt | What exactly happens when (in movies) the police trace a call and why can't they do it if the call is less than a minute long? | Technology | explainlikeimfive | {
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"text": [
"It's just a movie plot device. The phone carrier knows immediately where the call originated from. The police would get a warrant and the phone company would hand over the information. With cell phones, they would triangulate the call using 3 or more cell towers. Again, it is immediately available as soon as the phone makes contact with the towers.",
"It's instantenous in the digital era. All the data related to your call is stored, so even if you hang up, the police can still request the operator for the location of the call. Though it's possible that they can't get an exact location for your mobile, especially if it's turned off. Instead, they might only get the list of connection towers the phone was last connected to. Before being automated digitally, mechanic and electromechanic [telephone exchanges]( URL_0 ) needed a bit of manual effort to pinpoint the location of a caller. 1 minute wouldn't have been enough for it far as I can tell. Probably it'd been more like 15 minutes in the least.",
"The tracing the call as seen in movies is fake. The need to keep them on the line for a certain amount of time is just a plot device used to add tension to the scene. So the easiest answer is... In movies the ot sometimes require a phone trace. In real life this is a fairly quick process and unexciting and would result in a glance at a screen and a \"he's at the payphone on 5th.\" So by having an arbitrary time for the trace to work tension is added to the moment as it's suppose to leave the audience wondering if they are going to get the trace or not. (Spoiler: they don't)"
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|
8e5cac | Why are sites such as Netflix and Youtube able to stream high definition video on relatively slow internet, while other sites struggle to stream that same quality of video on even the best internet? | Technology | explainlikeimfive | {
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"text": [
"Compression is a wonderful thing. When you go to Netflix or YouTube, you aren't actually streaming 1080p or 720p. The feed you're getting is highly compressed, and your computer then renders and upscales it once you've received it.",
"* Netflix partners with ISPs and locates their content servers *inside* ISP facilities. This means your Netflix video doesn't always travel across the internet to get to you, it only goes from your ISP to you which is a dedicated hi-speed connection. * Netflix uses video compression to reduce the amount of data being sent to you. You don't really notice it because it's very good and also because most video you watch is compressed and you're used to it. Both cable and Sat TV providers use video compression even on their \"HD\" channels.",
"1) Netflix and Youtube have some of the fastest internet connections on their end with extremely high traffic capacity. 2) Netflix and Youtube have good compression algorithms that lets their streams take up less data mid transit and are decompressed on the watchers end. 3) They both have tiers of quality and do not actually allow their HD video to transmit to people who have too low of a connection."
],
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8e5fst | If fully electric cars are possible, why aren't hybrids more common, or even the standard? | Technology | explainlikeimfive | {
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"text": [
"They're very expensive to buy new, and there are very few being sold second hand as they're so new. As the technology becomes more popular they'll be produced on a larger scale and that will drive the price down. Also as they're around for longer they'll become easier to pick up cheaper second hand and this again will result in more people owning them.",
"A fully-electric car can be expensive... it also has its own limitations and complexities. But at least you get to eliminate the gas engine, actually carrying gas, a traditional transmission, etc. A hybrid adds expense and complexity to a gas-powered car without letting you remove any of the expensive, heavy, and complex parts a gas car needs! They sometimes offer advantages and better value overall, but they’re not as “elegant” of a solution as a fully electric car."
],
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8e6ak6 | What technologies are there so that your credit card information cant be stolen while in your wallet? | Technology | explainlikeimfive | {
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"text": [
"Information on a credit card is presented in three ways 1.) In printed or raised lettering on the face of the card 2.) Encoded on a magnetic strip on the rear of the card 3.) Stored within a microprocessor located on a chip embedded in the card If a credit card is located within a wallet, it's safe to say that interception via #1 is impossible straight off the bat. Interception via #2 requires that the magnetic strip be exposed as the sensor needs to be incredibly close to it, and must scan across it cleanly. Interception via #3 is impossible because there's no way to get the credit card information from the EMV chip. How it works is far beyond the scope of ELI5, but the entire transaction is encrypted; furthermore, transactions beyond a certain value are further authenticated with a PIN known only to the card holder."
],
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|
8e6zks | Why does turning batteries around make them last longer? | Edit to clarify: On things that take multiple batteries, swapping the batteries spots will sometimes let it run a little bit longer. Like this : -1+ +2- --swap-- > -2+ +1- | Technology | explainlikeimfive | {
"a_id": [
"dxt6mpp"
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"text": [
"I hope I am understanding your question correctly. A lot of times when batteries die in your remote control for example. You can swap battery in position 1 with battery in position 2 and they give you a little more life. You can also just keep the batteries in the same position and roll them. What happens is the confact between the two surfaces oxidizes (corrodes) just enough to increase resistance which causes the circuit to not work right. When you swap the batteries or roll them you break up this little bit of oxidation and the resistance in the circuit is reduced and everything works a little bit long. There also is some type of chemical effect going on but that is outside my wheel house."
],
"score": [
16
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8e7imz | How do websites that illegally stream movies and TV stay online? | Technology | explainlikeimfive | {
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"text": [
"From what I understand, some sports streaming sites operate out of countries/on domains where the local law doesn't care or have the resources to shut them down (.se or .sx) Not that I have any knowledge of any such sites, mind you.",
"When you say that the website is \"illegally\" streaming movies, what you really means is \"illegally according to the laws of some countries.\" But if you set up your web server in a country where what you're doing is not illegal (or the authorities don't care), there's not a whole lot that other countries can do other than be mad, and try to flex with economic sanctions if they think that it's worth it.",
"Whenever they get caught they just make a new website after their old one gets taken down. They have off site backups with mp4s of all their content, then they recreate the same website using a different hosting service/platform/country.",
"In addition to what everyone else here has said, some of these sites are merely aggregators and they collect the links to other video hosting sites, embedding the videos within the page but not actually hosting them. This makes them more difficult to take down. Sometimes specific hosts do get closed down (Megavideo for example) but the internet is so big that other sites inevitably spring up or take on the orphaned users. One user mentioned that some sites will change their URL. This is because the country that is in charge of that specific domain registrar may change their mind due to legal action. The domain (.com, .co, .net, etc) is basically a mask for the actual website's IP address, which tends to be a string of numbers such as 192.168.1.1. When you enter URL_0 , it's just shorthand for those numbers. An organization that wants to take a site down for copyright infringement can go for either the domain registration or the physical servers, both of which may be in different countries/jurisdictions. Going for one or the other requires it's own set of legal manuevoures That's why you see sites change their URL a lot. Usually, when a site is taken down at the server level, it requires an in-person raid in the country where those servers are present, requiring police coordination and court orders rather than simple legal threats."
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|
8e7suh | Why does a webpage take up so much RAM? | Technology | explainlikeimfive | {
"a_id": [
"dxt2lex"
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"text": [
"Compare it with cooking: The data downloaded contains the recipe for the webpage to be displayed. That recipe is used to render the page and to perform the interactions. Your recipe for a cake is just ten lines on a piece of paper, but the flower, milk, sugar, egg, flavours etc take up a lot more space."
],
"score": [
3
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|
8e95yz | Why is there a static sound when you unplug earphones from your device? | Technology | explainlikeimfive | {
"a_id": [
"dxtfy4x"
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"text": [
"When the headphone connector is all the way in, there are three metal contacts that line up with three metal contacts inside the device. As you slide the plug in or pull it out, the contacts touch the wrongs places briefly and cause a momentary short circuit. The short circuit causes the voltage to spike very briefly. Audio signals are just voltages that go up and down in level. So when the voltage spikes, it's literally the same as a really loud part of the music."
],
"score": [
8
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"text_urls": [
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|
8e9nxk | How did they code the first code without code? (Computers) | Technology | explainlikeimfive | {
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"text": [
"The first computers did have a single purpose, for example calculating trajectories: Add some values, press a button and you got the answer. It wasn't until later that multi purpose computers which you could program. The first methods of entering the code was, yes, programming the computer: Fill in the value for address 0x0000, press load, fill in the value for address 0x0001, press load, fill in the value for address 0x0002, press load. Etc. And then press the Go button. And if you got a power failure you started again at 0x0000. People got rather bored of this, and invented new ways to store programs: punch cards, which stored 64 bytes in one go and could be reused later on. Ticker tape, which could store as many bytes as the tape was long. And then somebody found a way to store data in a magnetic medium.",
"The first code was written in binary. Which the computers where designed to use to complete computations."
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|
8ebcli | What is the benefit of restarting a phone or computer on a regular basis? | Technology | explainlikeimfive | {
"a_id": [
"dxts9k7"
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"text": [
"Adding to this if allowed; does it make a difference whether you restart a phone or turn it off and then on again"
],
"score": [
3
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|
8ed54n | Why are real number data types such as float and double called "floating-point"? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Let's say you have 8 \"spaces\" to store a number. There's a few different ways you can store numbers in it: 1. Unsigned Integers. ######## lets you store numbers from 0-99999999 but no negatives or decimals 2. Signed Integers. ±####### lets you store from -9999999 to +9999999, a smaller number than option 1 but covers positive and negative. 3. Fixed Point Decimal ±XXX.YYYY only gives you -999.9999 to +999.9999. You could split it other ways, the point is that the data type is fixed when it's defined & can't be changed during runtime. 4. Floating Point Decimal ±X.YYYY \\10^±Z lets you represent both positive & negative numbers from 0.0000000000001 to 9999900000. You can say that the decimal \"floats\" depending on the size of your Z (mantissa) Floating point is the most common format for storing real numbers, giving a reasonable compromise between speed, accuracy & range. \"Arbitrary precision\" numbers that let you have any level of accuracy you want are also popular but they're generally supported by by libraries rather than CPU instructions so they're significantly slower.",
"It refers to the way the data is represented. Basically the \"point\" is not in a fixed place, hence it is \"floating\". Imagine you have a calculator display with a 10 digit display. If the decimal point was fixed in place after the last two digits, it would be fine for some numbers (e.g. 1234.56), but it wouldn't be able to display very small numbers like 0.00124. That would just appear as 0.00 So you let the decimal point appear at any place. You're still limited to 10 digits of accuracy, but they can be 10 digits representing small or large amounts. If you want to dig deeper into how it works, floating point numbers actually use something similar to scientific notation, but in binary. That allows it to represent very big numbers too, but not necessarily perfectly accurately because there may not be enough digits."
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8eebev | Why does pumping the brakes work better than holding the brakes when your car is sliding on ice? | Thanks | Technology | explainlikeimfive | {
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"text": [
"There's two types of contact friction: *static* friction and *kinetic* friction. Static friction is the force that it takes to push a stationary object and start it sliding/skidding across the ground. Kinetic friction is the force it takes to keep pushing something that is already sliding. Static friction is always greater than kinetic friction. Cars work by static friction. Even though the tire moves forward, the tire rubber doesn't actually slide along the ground (unless you're skidding or burning out). The point of contact between the ground and the tire is stationary, so the friction between car and ground is static friction. This friction is how the car moves forward - it spins its wheels to push backward on the ground, and so it pushes itself forward. When your car is skidding/sliding and you slam on the brakes, your tires lock up and start sliding across the ground. Static friction becomes kinetic friction. Since kinetic friction is lower than static friction, this means that the force your car can exert on the ground is lower. This means that your traction is lower, and your ability to control the motion of the car is lower. By letting off the brakes for a short time (either by pumping with your foot or by having an AntiLock Brake system do it for you), you allow the wheels to roll freely for a bit. This can give them the opportunity they need to start rolling along the road again instead of skidding across it, regaining the static friction and thus your ability to control the car.",
"If you have ABS brakes you can keep pressure on the pedal. The crunching sound is the brakes momentarily releasing so your car does not go into an uncontrolled skid, meaning you keep your ability to steer and may avoid a collision. Without ABS continuous pressure may result in your inability to steer while you slide on the ice.",
"It doesn't on a car with ABS. If your car has ABS do not pump the brakes that defeats the whole purpose. If your car does not have ABS, pumping them may help you retain some control of the car. But again if you have ABS and need to emergency brake put your foot down as hard as you can and keep it there. Your car will shudder or make noise; that is normal.",
"when driving (slidding) on ice, the WORST thing that you want to happen is for your wheels to stop spinning. Once they do this, you can NOT steer out of the way....pumping the breaks reduces the chances of your wheels locking up while increasing your chances to control the direction of your vehicle...ABS pumps your breaks 15x per second without locking up the rotation.",
"Both pumping the brakes and ABS help regain traction on the ice. If your brakes are continuously applied, then your tires turn into skis. When you depress the brakes, the tires will continue spinning so that *next* time the brakes are applied (either from pumping or ABS), it will keep enough traction to reduce your speed some more. With enough gradual presses/depresses, you'll shave off enough speed to come to a stop. As opposed to sliding dangerously on tire skis."
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8efvtc | How do movie uploaders actually benefit from uploading piracy content? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Hobby? Maybe they just enjoy watching movies and would like to give others their experience of the coughing, rustling and getting up as a shadow to go for a piss ....",
"Some people believe that all that kind of content should be made available for free, others might do it in the hopes of donations. Most uploaders are from countries with lax laws on that kind of stuff anyway.",
"Copyright infringement, generally speaking, is not a criminal offense. It is a civil tort. That means they're risking being sued, not going to jail. Some people actually do make money off of pirated movies. A lot of black/grey market groups are willing to pay big bucks to get pirated films so they can copy them and sell pirate DVDs. The guys who upload online are usually just doing it for rep in the community. It's a big deal for a release group to be the first guys to get out a new hot title (or the first to do it at good quality). Gets them tons of rep and goodwill in the scene."
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8ega87 | Why are movies filmed in much wider aspect ratios than TV? | Similarly, why are movie theater screens wider than home televisions? Shouldn't there just be one standard aspect ratio for film? | Technology | explainlikeimfive | {
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"text": [
"Part of the answer to this is the existence of TV. Films used to be shot in much more square aspect ratios, but when TV hit the scene, the studios wanted to come up with ways to differentiate their product from what you could just stay home and watch on TV. Because television sets were small (and the tube technology meant they needed to have a relatively square aspect ratio), studios began to experiment with wider aspect ratios, huge screens, color, and projects that emphasized all of the above. You couldn't see anything like *Lawrence of Arabia* or *The Sound Of Music* on TV. So the idea was that these huge spectacles would pull people away from their living rooms and get them out to the theaters. After awhile, people got used to the widescreen effect and basically all films switched over to that format.",
"I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why are movies filmed in 2.39:1 and not 16:9? ]( URL_4 ) ^(_10 comments_) 1. [ELI5: why is movies' aspect ratio becoming more and more \"rectangular\"? ]( URL_2 ) ^(_31 comments_) 1. [ELI5: if movies and cameras were always in a wide aspect ratio why where tvs square (4:3) for so long? ]( URL_5 ) ^(_10 comments_) 1. [ELI5: Why does a movie in cinema have a different aspect ratio than the same film released to the public on DVD, blue ray, or iTunes? ]( URL_1 ) ^(_5 comments_) 1. [I have a wide screen (16:9) TV... Why do movies still have the black bar at the top and bottom of the screen? Shouldn't it just fill the screen? ]( URL_0 ) ^(_11 comments_) 1. [Why do most movies have black bars? Why aren't they in an aspect ratio that gives you a full screen for a better experience? ]( URL_3 ) ^(_6 comments_)"
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"https://www.reddit.com/r/NoStupidQuestions/comments/3w445h/i_have_a_wide_screen_169_tv_why_do_movies_still/",
"https://www.reddit.com/r/explainlikeimfive/comments/6pkm0w/eli5_why_does_a_movie_in_cinema_have_a_different/",
"https://www.reddit.com/r/explainlikeimfive/comments/4v3fel/eli5_why_is_movies_aspect_ratio_becoming_more_and/",
"https://www.reddit.com/r/NoStupidQuestions/comments/6nh624/why_do_most_movies_have_black_bars_why_arent_they/",
"https://www.reddit.com/r/explainlikeimfive/comments/2zu989/eli5_why_are_movies_filmed_in_2391_and_not_169/",
"https://www.reddit.com/r/explainlikeimfive/comments/3mmbvw/eli5_if_movies_and_cameras_were_always_in_a_wide/"
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8ej6er | Why is it not possible to modify a file's name while it's open? | Technology | explainlikeimfive | {
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"Because Windows forbids it. There is no technical problem with allowing it, and in fact other OS'es generally do allow it. Windows uses a policy of locking files when an application is accessing them, which means they cannot be deleted or (depending on the type of lock) renamed. The reason Windows does this is (probably) to keep things simple and understandable from the user's point of view. What would happen if you deleted a file while an application was in the middle of reading from it? In particular, what would the application see? Would it be able to continue reading? Would it get some kind of error that it then had to handle? From a technical point of view, the answer is simple (the application would still hold a reference to the file, so it could continue to read and write the file as if nothing had happened), but from the user's point of view, Microsoft has chosen not to allow it. But these are policy decisions, not technical limitations. **Edit: ** To be clear, my explanation of *why* Microsoft has chosen this behavior is based on guesswork and half remembered blog posts by Microsoft engineers. Another plausible reason that comments have brought up is simply backwards compatibility. 30 years ago, DOS was created to behave this way (and that was perhaps just because it seemed the simpler way to do it back then), and it is possible that Windows has retained this behavior *solely* to preserve backwards compatibility. My guess is that both are factors. They certainly don't want to break backwards compatibility unnecessarily, but they also have a long record of introducing new functionality on an opt-in basis so that legacy applications aren't affected, and they could have done something similar if they wanted to allow renaming of open files if the thought it was a desirable feature. Regardless of the motivation for this behavior, it is a fact that the Windows kernel does support everything needed to allow you to rename or otherwise modify a file while it's open.",
"I can. (Linux) If, for example, I open a handle to a file and then move said file (eg here), it works like you might expect, I keep writing to the new file after the move: URL_0 However, bear in mind that this very much depends on *the program in question handles files*. For example, if I edit a file in `vim`, rename it (`mv`) and then save-quit, I get the unedited file under the new name, and the edited file under the old name. This is presumably because `vim` (a text editor) isn't maintaining a constant handle to the file. So unless you actually know how the program in question you're using works, it's risky business.",
"Apple also allow user to modify file name with the file open. You can even edit the name directly at the menu bar itself.",
"When we say we are \"opening\" a file, this could actually mean a couple different things depending on the application. The two primary operations we do with files is read and write. Compare this to filling out a form, or doing a homework assignment. Most of the time, you have to read some info on the form, such as a question, and then write something down onto it and then continue reading. Some applications will work the same way, they need to be constantly reading and writing to a file. Some programs (but not all) that do this will put what's called a \"lock\" on that file. Its like if you were in a group project and said \"I'm going to write by myself, because if we did it at the same time, we would get in each other's way\". Now on the other hand, think about if you were reading a book, or if your homework had an instruction sheet that didn't need any writing. It would be fairly easy to share with someone else. They could read over your shoulder or sit next to you at the table. You'd both be getting the same information, because neither of you is changing it. Applications can work like this as well. When they start, they'll do a preliminary read of the file, and forgoe locking altogether. Other applications can do the same thing at the same time. As others have said, windows is a bit more strict on this for the sake of user experience. But it's not always the case, simple text editors won't always lock the file they have open, and will let other programs make changes. Therefore, having the file \"open in two programs\". It all depends on what the application needs to do with the file.",
"When you try to open a file in Windows, Windows uses the file's name to identify it. Things could go wrong if the file name changed while it was open. That's why they disallowed renaming a file while it's open. When you try to open a file in Linux, Linux uses the file's inode number(basically like an employee ID, always unique) to identify it. The inode number remains the same for a file no matter what its name. Therefore you are allowed to rename files in Linux while they're open. Also understand that this will depend on the software used to open the file, because the software developer can decide between using a name to identify a file, or using the inode number. Hope that makes it clear",
"You can do it on a Mac. It's just a Windows thing?",
"lots of explanations but initially was because using the filename as a primary key was faster and used less space as CPU speed got faster and memory cheaper, developers started using a hidden index to refer to the file and the name would be a label - of course this leads to duplicate filenames"
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8ejckf | How do bands make sure their backing tracks are starting in sync with thier live music? | Technology | explainlikeimfive | {
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"Audio engineer here. Generally on smaller shows the musicians will trigger the start of their backing tracks with a drum pad/footswitch as previously stated. The drummer (possibly the rest of the band as well) will then play along to a metronome in their in ear monitors to keep in time with the pre-programmed backing tracks. In large productions there is a playback technician that is responsible for setting up an entire system that is basically a big metronome that can be as basic as above all the way up to also generating smpte or midi time code that can trigger cues to go off for lighting changes, video playback, set pieces moving, guitar effects changing, and other effects.",
"Could've been done in any number of ways; with a pedal or some other switch, the drummer might have had a pad or something to hit to get things going, it doesn't have to be someone stood at a CD player poised over the go button. What it almost certainly won't have been would just be one long timed track.",
"The drummer of my old band had a clock track metronome fed to his in-ear monitors. He knew there were X counts before a track started, and the metronome would keep him (and us!) on time. In our early days, we literally had the tracks on an ipod and he would start them. In the later days, tracks were moved to a drum pad for him. Worked like a charm.",
"The low budget way I used to do it. Stereo left and right. The left went to my in ear monitor system and I had a countdown that was not confusing. It was actually me verbally counting down, as well as the name of the song, so at the right moment, I started playing the guitar part along with a standard click track. The front of house was getting the stereo right signal, and that was the backing track. This only works with in ear monitors. Regular floor wedge monitors would allow the audience to hear the clicking sound."
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8ekiqa | why does airplanes have dual 3.5 mm headphone jacks instead of a single headphone jack? | Technology | explainlikeimfive | {
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"Way back when airplanes were built and entertainment systems introduced headphones were not a regular thing people brought with them. Headphones back then were expensive enough that making two pronged headphones discourages people from taking them when they got off the plane and saving airlines money. So why do we still have them? Well retrofitting IFE for airplanes is not cheap and leaving the old two pronged config is cheaper and airlines can just change the LCD and main IFE. So, cost savings are the reason we still have two pronged jacks in most airplanes. Also, airlines could save on maintenance since they had “redundancy” on the jacks, that you only had sound in left or right ear didn’t matter too much to the airlines."
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8ekl4g | What's the difference between CPUs and GPUs from a technical and logical standpoint? | Technology | explainlikeimfive | {
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"The best ELI5 analogy I have seen to explain the difference is : > the CPU is like a 4 or 8 lane highway at 100mph > the GPU is like a 2000 lane highway at 40mph While CPUs have a few big independent cores which are individually very fast, GPUs have a ton of tiny cores that are both slower and not completely independent. This makes GPUs really really good a computing the same thing over and over. And make them a lot faster than CPUs for computing pixels or hashes *en masse*.",
"CPUs can do more complicated calculations but they few cores 2, 4, 6 etc, GPUs do simple calculations but has thousands of small cores and they all have to do same operation.",
"A CPU is a generalist and a GPU is a specialist. The CPU can do a lot of different things well. The GPU specializes in doing a certain type of task extremely well. This means that when you try GPU type of tasks with a CPU it can do them but not as fast as the GPU would, but in exchange the CPU can do lots of different things you would not be able to do (or at least do easily) with a GPU alone."
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8elsr8 | Why does Adobe Acrobat Reader have so many updates? | Technology | explainlikeimfive | {
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"text": [
"The short answer is it's not a simple document viewer. Think about Chrome or firefox, they \"Just view HTML documents\", and well that means a lot of things, new features get added to HTML itself, people find ways to do stuff faster, and better ways to integrate other things into the browser. Like HTML, PDF is a document format that supports a lot of features, you can have a simple reader that supports the common things, or a complex one that supports everything in a PDF, Adobe has gone even further and added their own extensions and extra features. In the end this makes the Adobe products very complex, they support a lot of new and old features, many very obscure. But this makes them very complex, and it's a very old code base (so it's slow, and may be difficult to fix bugs, which can lead to bugs on it's own)."
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8emg49 | what SAP does for companies? | [SAP]( URL_0 ) is the biggest software company come out of europe for sure. but what it does? compaies use it for what? | Technology | explainlikeimfive | {
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"I used to work for them - their big general product is SAP ERP software, which is 'enterprise resource planning'. Best way to think about it is that they have software and databases that handle business logistics. Their big business is selling their software, then renting out consultants to teach people how to use their famously unintuitive software.",
"SAP makes enterprise business software. In simple terms - they make the software that let's companies do things like manage payroll, run HR, and resource planning across the entirety of the company. They make a huge array of products so making a list is problematic. But if you imagine the typical functions of a business, odds are decent SAP makes software that helps with it.",
"It's software that help connect all of the business functions together, so sales, payroll, inventory, and other information are all in one place to help management get a better complete picture of what is going on. In theory anyway, it's ridiculously hard to set up and even then it's never really \"done\" being set up . . .",
"i'm a materials coordinator at my plant. a huge chunk of my job is ordering supplies... SAP's system not only handles the logistics of placing my order with an approved supplier, but also the warehouse checking the item in, and the invoicing, where we pay for it. on the other side, it also tracks how much we will use each day and predict when we will need more, triggering a warning to place an order... multiply that out, for the over 300 items i order, and it is a huge timesaver, even with all its problems. and thats just the inventory side, as others have said, it ties in costing, payroll, shipping, and about a dozen other things."
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8enpem | How do electrical instruments work? | Tempted to give my character an electrical voilin for a D & D campaign but i don't really know enough about how they work. how does it change sound, and would running a current through a voilin be enough? | Technology | explainlikeimfive | {
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"No. Electrical musical instruments work by having magnetic pickups which output a signal based on the frequency of the vibrating metal string. This output current is then amplified and converted into sound by the amplifier.",
"When you take a string, stretch it taut, and pluck it, the string vibrates and makes noise. In a normal stringed instrument like a guitar or piano, the same thing is happening. The shape of the surrounding instrument is then used to amplify the volume of the vibrating strings. With an electric instrument like an electric guitar, the vibrations in metal strings are too quiet to amplify in that way. Instead, a device called a pickup is used to convert the strings' vibrations into electrical signals. These electrical signals are sent to an amplifier, which converts the signals back into a sound loud enough to be heard."
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8epp29 | why can't we extract drinkable water from ocean , when there is water scarcity? | Technology | explainlikeimfive | {
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"text": [
"We can, and do. But it is extremely expensive to do so. You either have to spend a massive amount of money and fuel to build distilleries that evaporate out clean water, you have to build massive filter systems that take a lot of electricity to force water through filters small enough to filter out salt. Both also require frequent cleanings (filter changes or evaporation chamber cleanings and have to be absolutely massive buildings in order to produce enough water to provide for a city.",
"We absolutely can. [Desalination is a very real thing.]( URL_0 ) The problem is, it's not terribly efficient and takes a lot of energy to do, so it's not really practical to do it on a large scale. But, as technology marches on this too will get cheaper and more efficient, so maybe someday they'll be able to solve all our water problems but not today."
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8epp98 | what is in programming the "SCRUM" and "AGILE" work methodologies? | Technology | explainlikeimfive | {
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"text": [
"Scrum is a type of agile development framework. Suppose you have a chore to do - mow the lawn. Agile essentially says that instead of mowing the entire lawn, collecting all the mowed grass, putting the mower away, etc just to find out you didn't do it the right way, you can instead mow small sections of the lawn and check with you parents after each section to make sure you did it correctly, thua being able to correct smaller mistakes more frequently rather than correct one huge mistake at the end. Each of these sections of lawn you can consider to be \"sprints\", or the key element of Scrum."
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8epz57 | Is it possible for 2 QR codes to be the exact same thing? | Technology | explainlikeimfive | {
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"text": [
"Yes. QR codes just contain a small amount of data. It could be a registration number, a link to a web page, or some other small piece of information. The impact of two codes being the same would depend on what the codes are being used for."
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8exoqu | How does an electronic device instantly switch to battery power when unplugged from the power source? | Does a device draw power from it's battery even though it's plugged in so there's an overlap? Or is there a short moment in time where the devices switches from wall power to battery power? | Technology | explainlikeimfive | {
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"text": [
"At least for phones/laptops/tablet-type devices... The battery is always running the device. The cord simply charges the battery IF it's plugged in. So there's not really any 'drop' or switching."
],
"score": [
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8exoxq | how a robot can find coordinates of an object by just looking at it with its camera | Technology | explainlikeimfive | {
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"text": [
"Imagine someone handed you a photograph of a room that you had never seen before. Given a lot of time and effort, do you think you could build a small scale model of that room using cardboard? Most humans could. Computer vision is getting a lot better at what humans do naturally - figure out the 3-D structure of their surroundings just by looking at it. Humans do it much easier using two eyes - it helps in judging distances - and until recently robots preferred to have two eyes, too. However, humans are still remarkably good at navigating and mapping using just one eye. Robots are getting pretty good at that too, by watching how things appear differently as you move around and examine them from different angles. If you're interested in the more detailed mathematical and scientific explanations, you could do a Google search for \"monocular visual inertial odometry\"."
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8ez1vf | How does an operating system for the visually impaired look? How does it work? | Technology | explainlikeimfive | {
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"text": [
"While I would love to explain it to you; The YouTuber, Tommy Edison, explains it perfectly. He is actually blind and He describes how he does it. You can watch the video [here]( URL_0 )"
],
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8f0dzg | Why do older video games require fewer ports to be forwarded than newer video games? For example, CoD: WaW released in 2008 requires only one port to be forwarded whereas the newest CoD requires nearly one hundred on PC | Technology | explainlikeimfive | {
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"text": [
"Network engineer here. A few things. I should say I've never had to forward a port for a game. Make a hole in a firewall, but not port forwarding. As to port usage. Gaming networks have both gotten more complicated with game using separate internal apps for different processes. Things like voice comms, gaming networks, updates, etc. It used to be a game was an independent program, now it is many programs tied together. Also some game programming has gotten sloppy and bloated. Programmers used to strive to make the most of the smallest amount of data. Now with basically unlimited bandwidth and storage things skyrocket."
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