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9mvfga | Why is it better to charge a modern smartphone from 20% to 80% even if it implies more charges rather than the old way(let it drop to 0 and then full charge)? | Technology | explainlikeimfive | {
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"It's not. This is one of those ongoing myths that for some reason won't die. Modern smartphone batteries have no issues at all regarding charging or battery strength that, and all of these \"only charge to X%\" is complete nonsense."
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9mvueh | How can robocalls use YOUR cellphone number. | Technology | explainlikeimfive | {
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"The plain old telephone system (POTS) is plain and old. It was built long long before we cared about security There's nothing in the system right now to enforce that a number shows up as itself. Many robodialers just report a different number when connecting to the network which makes it appear as though the call is coming from a different phone than it is There has been discussion as to how to improve the POTS recently, but phone companies would be footing that bill without benefitting at all. Upgrading the POTS is a huge expense with basically zero payback so it's unlikely it'll happen anytime soon"
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9my98g | What exactly are firewalls in terms of computer security? How do they work? | Technology | explainlikeimfive | {
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"Easiest way to explain it is its basically like a filter that lets certain predetermined computers and programs pass and blocks others",
"Conceptualize internet traffic as road traffic in the form of trucks. The firewall is border security that separates your home from your (untrusted) neighbouring countries. Each truck that wants to enter the country has papers that tell the border security officer what the origin of the truck was (IP address of sender), where the truck wants to deliver its load (port/application that is going to receive the payload) and the order form of the one who requested the load (this is the web page you clicked on in your browser). More advanced firewalls will also want to look inside your truck to see if there are goods you're trying to smuggle in (malicious payload). Whenever the border security officer sees something it doesn't like, it denies the truck entry. Firewalls are also able to work in the outgoing direction. Here, the border security officers check if the truck wanting to leave the country is legit and whether it's trying to smuggle contents out (a virus within your system is trying to send your personal data to a criminal).",
"Every machine connected to the internet has an IP address, which identifies it. In the simplest terms a firewall is a list that says \"let these IP addresses through to your PC, but not these ones\". Your computer also has software on it, some of which want to access the internet. Your firewall is a list that says \"let these programs access the internet, but not these ones\". There's also ports that can be blocked and not blocked, but that's perhaps going beyond ELI5. Everything that comes and goes in and out does so via ports, which all serve a specific purpose: programs or functions will use certain ports because those ports are set up to facilitate the way those functions work. Firewalls can block those ports too. For example, many firewalls now block Port 445 because it's a very easy port to use for hackers to get into computer networks.",
"A firewall is like a border patrol agent that lets good people (whitelisted programs) through and denies bad people entry.",
"A firewall is, at its most simple, a set of rules for what can and can't cross a network boundary. That boundary can go anywhere the security engineer wants; in an enterprise setting, it usually goes at the *network perimeter,* or at the point where the company's internal network crosses over to the public internet. It can be configured to block certain IP addresses or ranges of addresses, certain ports or ranges of ports, to *only allow* certain addresses or ports, or even to block all incoming connections that weren't initiated from inside the firewall."
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9mz35u | how, with modern technology, can you still have a call show up as "unknown" with no number? | Technology | explainlikeimfive | {
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"[Because hiding from caller IDs is a specific function built into the phone system.]( URL_0 )",
"A private number means the number was blocked with intent. If it comes from a carrier that does not provide caller id it will show as unknown."
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9mzfj7 | California Proposition 65 Mess. | Technology | explainlikeimfive | {
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"A company can get in trouble for not informing consumers of any presence of a chemical that could be considered toxic or carcinogenic. It sounds reasonable at first, but the issue is these chemicals are dangerous in high concentrations - not the concentrations we’re exposed to on a daily basis via food, air. Take the coffee mess that happened earlier this year for example. Roasted coffee contains acrylamide, which we believe is a byproduct of the Maillard reaction IIRC, which involves the breakdown of starches and sugars and their reactions with amino acids to create browning. Not only does coffee contain trace amounts of it, but every other food that contains starches and is cooked. Acrylamide in abnormally high concentrations (read: concentrations you’ll never experience) is demonstrably cancer-causing to mice. There’s been little research of its effect on humans. Prop 65 s a nice idea, but in practice companies will put a warning label on their products to avoid a lawsuit. There’s no penalty for an unnecessary warning label. Short answer: the implementation of Prop 65 is so shitty that you really can’t glean that much useful info from it.",
"I can't tell if your question is how do you the consumer use the information or how should future law makers use the information. If it's you the consumer, a good starting point would be to read the documentation used to add the chemical to the list. A good example of why is chemicals like Titanium Dioxide, that's used for lots of things (particularly as a white pigment and as a hard abrasive). It's on the list for it's use as a sand blasting abrasive (if the particles are inhaled it's possible they could cause lung cancer). It's use as a white pigment is much less likely to be inhaled (when was the last time you inhaled say toothpaste?) so while your toothpaste that contains Titanium Dioxide probably got the label, you can pretty safely ignore it. Learning more about why a certain chemical was listed, can improve your ability to mitigate the risks associated with a product containing said chemical. Also, as a citizen, it's helpful to consider the unintended consequences of a law, rather than the response only of those with perfect intentions. Before voting yes, ask yourself what's the cheapest way someone could comply with this, and if that's not what you want, consider voting no. If you're asking how lawmakers can make a more useful law. They'd be wise to consider: * a different enforcement method, Prop 65's enforcement method is cheap for the state (citizens sue companies selling products containing a chemical with damages applied per unlabeled product sold), but it also provides a massive incentive to cry wolf over any ingredients on the list. * to add conditions more like a Material Safety Data Sheet, sticking with our example of Titanium Dioxide, [here's an MSDS]( URL_0 ). It also explains the cancer risk, but provides very useful context that as a pigment in other products (like your toothpaste) it's likely quite safe. A warning label that included conditions like \"if blown\" or \"if eaten\" would probably be far less alarming as most labelled products aren't intended to be used in that manner. * safe harbors like to require labelling only when a chemical that is a cancer risk in a concentration exceeds a listed concentration. Prop 65 allows companies to do this, but doesn't give \"safe\" concentrations which means companies have to spend the money to win a lawsuit proving their product has the chemical at a safe concentration, and it's much cheaper to just label the product than prove it safe."
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9mznp8 | Why do washing machines have windows? | Technology | explainlikeimfive | {
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"I’ve only seen doors on front loaders and a few very high end ones with those special wash baskets on top. Front loaders do for a very good reason, so you can make sure it has drained before you open the door.",
"If you're supplying a laundromat, it makes to have washing machines where people can see, at a glance, whether one has another person's clothes in it or if it's free to use. Front-loading washing machines also are easier to reach into to retrieve your clothes, unlike top-loading, so a laundromat is going to use windowed front-loaders. It's also important, for front-loaders, that people know if the inside filled with water if they're going to pull it open. In homes, where everything is personal use, most people I know use top-loading washers where there are no windows. You can just open the lid mid-operation with no risk of water pouring out."
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9n1swp | What did people use home PCs for in the 70s and early 80s? | Technology | explainlikeimfive | {
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"We got our first home computer in 1981. I was in junior high, so I used it for games, and word processing for homework -- papers and such. My dad used a spreadsheet program for some things, and I also used it to learn how to program on it. By 1983, we had a modem and we were doing things like connecting to BBSs and commercial online services like CompuServe for discussion forums, downloading software, research and whatnot.",
"It was a mix of hobbyists and people who had some kind of business related reason to have one. Word processing and spreadsheet applications for bookkeeping were both a big part of the early appeal of owning a computer.",
"The earliest PCs, which are from the early 1980s, were mostly useful for mathematical/scientific tasks, since they had very limited functionality. Ones from the mid-to later 1980s had a lot more things they could do. [Here's an example!]( URL_0 ) Pretty much the same things we would use them for now, except for the internet--word processing, accounting/keeping track of finances, games. I'm 30, and my house had a computer in it from when I was very young. It was the early 90s, not the 80s, but I remember writing assignments on it for class, playing games, both educational and not, and learning basic programming (my dad taught me how to write a program in QBASIC that asked me math problems and then told me whether I was right or wrong)"
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9n1tsp | Why can games like Fortnite run well on mobile devices, while not being able to run on home computers with similar or better specifications? | Technology | explainlikeimfive | {
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"disclaimer: I haven't played fortnite, on any device. ~~so 720p on mobile isn't the same as on a tv. It's describing the density of pixels and not the total amount. That's already a huge difference that mobile can take advantage of.~~ Also mobile might use lower quality assets (lower resolution texture, less shrubs, less triangles in models etc). On top of that there's a plethora of rendering technique you can just not use. The game will look a little worst but this is mitigated by the small screen. EDIT: yeah I'm wrong about the number of pixels being a measure of density. But most phones still have less pixels overall to render than a standard 1920x1080 screen and that's a huge help for the GPU. Iphone 6 has ~1/2 the number of pixels that standard HD has."
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9n5w21 | How do photographers take pictures of lightning? | I'd assume there is some kind of sensor that triggers the shutter but even then it seems like the lightning would flash too quickly. On the other hand maybe something to do with exposure? | Technology | explainlikeimfive | {
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"It's exposure. Done correctly with a tripod, you do a long exposure and cross your fingers. At least , that's how I did it back when I was still doing photography",
"Long exposures. The shutter will be open for 30 seconds or more every time. This not only lets enough light from out of frame lightning or other dim sources expose the surroundings, but of course you have that entire time for a strike to occur in frame.",
"Another option...record video of one area during a good lightning storm. When you play it back, do so in slow motion if you have that option and if not just be quick to press pause. When you have your image, screen shot it off the vid. It makes for some great pics! Two of my good captures: URL_0 URL_1"
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9n6bpr | How do wireless phone chargers work? | Technology | explainlikeimfive | {
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"The charger base makes a varying electromagnetic field. A coil in the phone, or plugged into the phone, absorbs this electrical energy and produces voltage. The phone's battery charging circuit uses this voltage to fill up the battery.",
"When electricity goes through a coil of wire, it produces a magnetic field. If you change the amount of electricity (voltage) through the wire, the magnetic field also changes. If you put a second coil of wire into that changing magnetic field, you will get electrons moving back and forth through that new coil of wire. The negative charge of the electron is attracted to the magnetic field’s positive side. Electrons moving is what electricity is. So the charger is a coil of wire with a changing voltage going through it. The phone also has a thin coil of wire in it. When the phone gets inside of the magnetic field of the charger, it gets electricity and starts charging. This process is called induction."
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9n7w2b | Would it be easier to colonize Venus? | Technology | explainlikeimfive | {
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"The probes we have landed on Venus's surface last less than an hour. The pressure and temperature are so high the probes melt. Pressure **ninety times as much as Earth** with temperatures of 470 degrees C/878 degrees F. Cooling is not the only issue, it's also still going to be like being on the bottom of the ocean. Atmosphere has no water vapor, no oxygen, and is basically mostly made of sulfuric acid. Interestingly, there is an area in Venus's atmosphere where pressure is comparable to Earth surface pressure, about 50 miles up. Venus is also closer and easier to travel to. The fact humans could never colonize the ground of Venus makes it a terrible spot to colonize, although scientific study at a floating cloud station would be pretty cool.",
"> If we could build a satellite large enough to block sunlight from reaching Venus I think you are forgetting just how big the Sun is. Or Venus, for that matter. In order to \"block out the Sun\" you need a satellite at least as big as Venus itself, otherwise it will only block a small patch. Also, the closer the satellite is to the Sun, the *less* it would block."
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9n9wbk | why does Google Crome use so much RAM? | Technology | explainlikeimfive | {
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"Largely speed optimizations. A program that wished to have minimal memory usage that drew a web page (one that had two overlapping images for example) would download the two images, calculate what the overlapping images should look like, and draw the web page with that combined image, and then send it to the screen, after each step it would through out the source files because they take space, so when you scroll for example, the page may need to be re-rendered, and since the source files are missing you need to go get them again, and redo the rendering. All this work just slows down the performance when scrolling. One common way to speed up applications is hold on to this stuff as long as possible, when redoing rendering you already have the merged image, so you can start there. Chrome additionally keeps the completed render of the last few items in the history, so when you click back it doesn't re-render, it just pulls up the saved copy from last time. Chrome also has a process per tab (provides security and helps a bit with speed as the tabs can't really interfere with each other), but this also means that if you have the same site open in two tabs, then chrome has probably rendered the whole site twice, once for each tab, and kept all of it in memory. In general, it's way faster to sort through a huge database of completed work than it is to re-do the work every time something minor changes, so chrome in goes for a huge amount of completed work saved in memory to speed stuff up.",
"The previous answers give good analogies, but I'll try to clear it up without getting too technical. It relies on the difference between Processes and Threads. Think about something that requires lots of different processing of different factors to ensure the outcome, such as driving. If you think about driving the car being a Process, and all of the smaller tasks involved as Threads, for example checking the mirrors, checking speed, changing gears, braking, accelerating etc. Your brain is allocating significant resources to the whole Process, and each Thread within that Process uses a small part of that brain power and each of these Threads is communicating with each other in order for you to drive the vehicle. For example the thread for your eyes sees a deer in the road, it sends a message to the thread used for pedal control which causes you to slam the brakes on. To bring this back to Google Chrome, each Process is designated space in the RAM of the computer. Threads of a process operate on that designated memory. In Chrome each new tab is a different Process not a different Thread, which means each tab is being designated a decent sized chunk of RAM to handle its own threads. This sounds inefficient, and it is in terms of memory, however the reason for doing so is that if one of the tabs crashes and causes an error only THAT PROCESS i.e. that tab will fail, not the whole browser crashing. This makes it useful to avoid losing any currently unsaved or in progress work on other tabs."
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9naeyb | why are mobile companies removing headphone jacks from smartphones nowadays ? | Technology | explainlikeimfive | {
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"Headphone/3.5mm jacks are currently the thickest part of a lot of smartphones, so it basically serves as a hard limit for how thin you can make a phone. Remove the headphone jack and replace it with something thinner (or don't replace it with anything) and suddenly you can make the phone thinner. Much less importantly, it's one more thing to have to make waterproof if you're making a waterproof or water resistant phone.",
"APPLE only did it because they want headphones/IEM etc manufacturers to pay for their Lightning connector (MFI certification etc), allowing them to have an easy revenue. They can’t monetise over the headphone jack because it isn’t “theirs”. Lightning connector on the other hand, is PROPRIETARY. here is a good article: it comes down to making a determination about the true motives for removing the jack. Is the trade-off in audio quality improvement the main motive? Or is the company simply making a cash grab to sell more Bluetooth, USB-C, or Lightning accessories? For several companies, we see a clear benefit. In the case of HTC, Essential, and Razer, the tangible benefits of removing the jack are clear in the end product. For HTC, we get the excellent USonic headphones in the box with the phone, in addition to the Edge Sense technology. Essential made one of the most beautiful Android handsets we've ever seen, and packed a sizable screen and battery into a tiny body. Razer served their core gaming audience with a bigger battery and improved in-game performance. Others like Apple and Google haven't quite convinced me that their decision is paying off yet. URL_0",
"So they can sell Bluetooth headphones (which they also produce and distribute) to make a bigger profit. Same reason MACs have crazy weird-shaped ports... So you have to buy the adapter also made by Apple.",
"To make you buy more shit (which most people don't want to do), despite the huge decrease in compatibility (which most people would have preferred), and claim it was because people needed thinner phones (which most people don't want).",
"You mean someone else has done this besides Apple?",
"It comes down to space. There is a constant drive to make smaller or slimmer phones with larger screens and better battery life. With those kinds of pressures, the internal space becomes precious. From a design standpoint, any hardware component in the phone must be weighed against the space it occupies (and thus deprives from another potential feature). The headphone jack has been redundant for a long time. It is a single purpose physical connector whereas other connectors (like mini or micro USB or USB C) are both smaller and capable of performing the same function as well as other functions. And that's before we get to wireless connection technology (bluetooth). The only downside to removing the headphone jack is forcing the end-user to purchase new accessories that are compatible with the new standard you are moving to. That held off the move away from the 3.5mm for a long time (and no one wants to pick a new format that doesn't become the new standard). Apple went first. In hindsight it makes sense that Apple would be the first since iPhones were more distinct from other smart phones (in both hardware and software) which makes iPhone users less likely to switch to another brand of phone and Apple could promise that the new connector would be their standard going forward. Other phone companies could not be as sure as Apple on these points."
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9nam7f | Why do electronic cigarettes use Glycerine/PG instead of just using water? | Technology | explainlikeimfive | {
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"text": [
"Have you ever tried inhaling water? It doesn't do very good things to you. Additionally PG and VG are very good and carrying flavour."
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9ncboz | What is the subtle difference between the Internet and the World Wide Web? | Technology | explainlikeimfive | {
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"The WWWeb is really (if you want to get technical) only talking about web pages and websites. But the Internet is the platform overwhich the Web is delivered. Like Netflix - you use a website to browse netflix in your computer browser... but if you use a SmartTV or a mobile device app you're not - the app is contacting Netflix's content servers directly over the Internet. Music streaming, WhatsApp msgs, iTunes downloads all use the Internet but not the Web.",
"The World Wide Web is just one part of the Internet. The Internet is the connections between many computers all over the world. The Internet includes e-mail, file sharing protocols, voice chat, and many other ways that we can send information using computers, while the World Wide Web refers solely to websites.",
"The internet is like the entire US road system - freeways, highways, local roads, private roads, toll roads, etc The WWW is a subset of that - like just the passenger cars traveling on that system of roads. E-mail traffic is another subset (just mail trucks), FTP is another (freight trucks), etc"
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9ncqyy | Why is using the wrong fuel killing an engine? | Let's say i put diesel in a gasoline engnine. both fuels explode and propell a piston. why is the one damaging while the other one is fine? | Technology | explainlikeimfive | {
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"A small amount of diesel in the tank of a petrol engine is not a problem. The will preform worse as it is harder to ignite. A large amount of diesel will result in fuel that the engine can't ignite so it will not work and you need to clean it. Normally no permanent damage is done but seals and injector might fail. petrol in a diesel engine can destroy the engine. One part is that diesel lubricate but gas do not so fuelinjectors and pumps might fail. The next problem is the cylinder. A diesel engine compress the fule a lot more then a petrol engine. Both diesel and petrol will ignite when compressed. Diesel will ignite when the pitons is at the top and start to move down. Petrol ignite at a lower pressure. So it will ignite before the piston reached the top and that can damage the engine",
"Why is it okay to put wood into your fireplace as opposed to gunpowder? They both burn and make heat right? In this case it’s a difference between *how* they burn/explode that makes a difference. In engines diesel explodes when you compress it far enough, but gasoline needs a spark to start the process off. If an engine is built one way and you try to run the other, at best your engine won’t work, and at worse your engine will be ruined forever.",
"Gas needs a spark to go boom, diesel needs a squeeze to go boom - two different processes for different types of engines.",
"Diesel is basically a light oil. Gasoline engines do not produce the right environment to burn it correctly - diesel requires high heat. So in a gasoline engine, the byproducts of combustion, soot, foul the spark plug, gum the valves and cylinder, and can cause the cylinder to misfire, fail to hold combustion pressure, or even spontaneously ignite if you have burning embers while you pump more fuel and air into the cylinder - which will burn all the way up the intake of the engine, causing backfire. If that spontaneous ignition happens inside the closed cylinder, then you will get odd shaped, or multiple pressure waves, which can occur at the wrong time -when there's nowhere for the pressure to go, or slap into each other, and either way, cause physical damage to the walls or piston. Diesel is also a low quality fuel, filled with contaminants, and the fuel system has to be designed with that in mind - otherwise, diesel clogs gasoline injectors. Diesel is ignited by compression. Compress a gas, like air, and it gets hot. Try it with a bicycle pump - there's a reason it gets warm, and it's not from the pump parts rubbing inside. Diesel is stable and predictable, and will ignite under compression at the right time, every time. Gasoline, on the other hand, is unstable, and will ignite at the wrong time, every time, in a diesel engine. Then you get ping or knock like I described above inside the cylinder, and you cause physical damage."
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9nefib | Why does a computer take longer to copy a file than to move it? Shouldn't it be the same since it's all data anyway? | Technology | explainlikeimfive | {
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"The reason is that moving a file is just changing the index location. This is not true when moving to another partition. Where's copying is a true read/store (to memory)/write data. Typically moving is always faster, unless you move to another partition. Which is basically a copy+delete operation.",
"I’m not a computer expert, I know a little about programming, but I would think that when file is being “moved” it’s probably being given a different address in the computer. In other words I don’t think it’s being deleted and reconstructed in another location, it’s probably just being assigned a different address. Whereas copying a file would have to replicate a file and construct it elsewhere. Again not an expert at all so I could very well be wrong."
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9nf9jn | how do astronauts navigate in space? | Technology | explainlikeimfive | {
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"Well first, the magnetic field of the Earth extends far out into space, but that's just an aside. There are many more ways to navigate than just using a compass. Most spacecraft navigate using some combination of inertial guidance, star sighting, tracking from grounds stations, and or global positioning satellites like GPS. Astronauts also are almost never actually flying the spacecraft. It's not like driving a car. The entire launch and ascent is per-programmed and executed by the computer. Docking with the station can be done manually but it can also be performed automatically, and all other on-orbit and de-orbit maneuvers are done by the computer.",
"Mathematics, engineering and careful timing allows everything to be planned ahead of time. The rocket is designed to produce a specific amount of thrust based on the weight of the cargo and people. This thrust makes the rocket go fast, but not too fast. The people who plan the mission have the rocket made so it has just enough speed to reach the ISS, no more and no less. The rocket is launched at a specific time so it intercepts the ISS, directly. No need to get to space and start chasing the ISS. Finally, there's \"ballistics\". The rotation of the earth, the wind direction and the latitude of the launch site all affect the direction of the rocket when it takes off. These factors are all known ahead of time. The direction and path of the rocket is pre-planned to compensate for them. This ensure the rocket goes in the proper direction."
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9nj99n | How does an app like Measure on the iPhone work | My guess is something to do with cameras and focal points and then maybe triangles and some maths | Technology | explainlikeimfive | {
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"Im sorry, but it never works for me, so I’m gonna have to say it doesn’t. It actually uses apple’s augmented reality kit. It finds a bunch of points in the space and tracks them as the phone moves."
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9njezu | If camera lenses are round, how does the image or video differ in landscape or portrait modes? Shouldn’t the lens capture the same image dimensions however it’s rotated? | Technology | explainlikeimfive | {
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"It's not the lense that captures the image, it's the cameras image sensor. The shape of that sensor usually is 4:3 (like old TV's). For different shapes the camera/phone digitally crops the image."
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9njnel | Why did old cameras record and old TV's displayed images in a more square ish shape, and now the modern ones record/display images a lot more in a rectangular shape? | Technology | explainlikeimfive | {
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"As stated before, a more squarish shape is more natural due to how lenses work. The film ratio of 4:3 was chosen because of the area of the film available for the image after the sprockets are put in. When TV was popularized, it chose the same ratio. In response to this, movie studios wanted to make the movie experience different than the TV experience. So they started doing more rectangular ratios. From 4:3 to 16:9 to 2.39:1 and beyond. When TV technology improved, they decided to more closely match movie theaters, so they adopted the 16:9 ratio.",
"As square shape, like the famous 4:3 resolution that many old TVs had, are just what you would build if you had no real thought put behind it. Aspect ratios that are not very even to 1:1 don't really enter the mind if you don't think about it. Those ratios evolved over time, as we understood the medium of film and picture more, leading to the ratio adapting to our actual field of vision, which is less square shaped and much more wide than tall.",
"The older tv format is 4:3 . It is a standard from movies known as the Academy ratio of 1.375:1 that was established in 1932. 4:3 can also be written as 1.33:1 The wider format that is common in movies today was introduced in 1953 in part as a way do differentiate from TV. The common wide format is 2.35:1 The 16:9 format (1.77) of TV today is a geometric mean of the TV format 4:3 and movies of 2.35:1. You can calculate is as sqrt(1.33*2.35)~1.77 It is the formant where you can display both and have the minimal amount of black bars on the sides or above and below. TV later changed to used the whole screen in a 16:9 format."
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9njsf1 | Why is there still a mirror in a DSLR (digital single lens reflex) camera? | I fully understand, why you'd need a mirror in the analog world. But why are there DSLR cameras having a mirror, too? Is there some advantage to it? | Technology | explainlikeimfive | {
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"It's so the viewfinder can optically provide the user with a true view of the image being taken, as opposed to electronically.",
"To expand on what other have said. & #x200B; **Part 1** & nbsp; Prior to the current generation of mirrorless interchangable lens cameras (MILC), DLSRs still had superior autofocus. The reason for this is that the mirror allowed DSLRs to use a second sensor ([PDAF sensor]( URL_0 )) that was build specifically for autofocus. This mimics the process that film SLRs used, because obviously film can't focus. Autofocus sensors are much smaller and purpose built this allows them to transfer data much faster and more specific to the job of focusing a lens. A Mirrorless is forced to use the main imaging sensor for autofocus. This is problematic because it is MUCH bigger and only allows [CDAF]( URL_1 ). This means more data has to be transferred and most of that data isn't useful for the purposes of autofocus. & #x200B; That was the past. More recently camera sensor makers (i.e. Sony, Canon, and Samsung) have started embedding PDAF pixels on the main imaging sensor, this allows for PDAF on the main sensor. The gap between DSLR and MILC has closed. & nbsp; **Part 2** Again prior to the current generation, One of the main complaints about MILC is that the electronic view finder (EVF) was laggy because of a slow refresh rate and imprecise. An optical view finder (OVF) \"refreshes\" at the speed of light. This has changed dramatically. EVFs have come a long way. However there are still many people who prefer an OVF as a matter of person preference to an EVF.",
"Cheaper, reduces drain on battery, the screen resolution on the back side isn’t as good as the eyecup and is susceptible to glare. Overall the traditional way works, is cheap and why mess with something that works. The only real benefit of getting rid of the mirror is removing the small vibration from the mirror flipping out of the way of the sensor. High end cameras actually do have mirrorless options but it just isn’t worth it for normal to mid-range cameras.",
"When digital cameras first started they basically took their 35mm film camera designs and replaced the film part with the digital sensor in the design. This made it easier for photographers to switch because the new camera tech wasnt as intimidating, and easier for manufacturers to transition since they already had a lot of the design figured out. Nowadays people are used to digital so companies can move away from the SLR model. One of the benefits of removing the mirror is removing a moving part that can fail. New mirrorless cameras have no real moving parts, which helps them last longer. The mirror shutter is one of the most fragile parts of a DSLR."
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9nnqdf | Why are the chips in debit cards a thing? | I've always heard they're "more secure" and "faster payment", but half the time the chip readers at stores I go to are down or take three times as long as just swiping. And I dont understand how it increases security? | Technology | explainlikeimfive | {
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"When you swipe the magnetic stripe on your card, the exact same information is transmitted each time, including a static security code. If someone copies this information, they can just put it on another card and use it. The chip sends most of the same information, but instead of a static security code generates a dynamic security code. A thief can't just easily copy the same information onto a magnetic stripe either because they won't have the static code that goes on the stripe either. Without the right security code, the payment network will reject the transaction.",
"If you're in the states, no one forced businesses to upgrade to the full chip and pin system, so you're not seeing all the benefits either. In Canada, you never use the magnetic strip anymore. You insert the card and enter a PIN, or you even just tap the card (usually reserved for smaller purchases) and it's just as fast as swipe, and you don't have to stop and sign anything.",
"You know that 3-digit code on the back of your card? It's called a CVV. It's job was supposed to be to keep card numbers from getting stolen and used later by requiring that CVV in your transaction. If you go to Amazon and buy something, chances are you'll need the CVV. Physical card swipes have never cared about that code. So if I stole your credit card I could go and use it at a gas station, provided I know your zip code. In fact, there are even a number of ways to skim your credit card number and then print that into a new mag stripe on a second card. Chip and PIN cards have a couple of features. The first is to eliminate risk of people skimming cards because when the card number is actually swiped, it tells the card reader that it has to use the chip instead. Printing out mag strips is much easier to counterfeit than pulling the chip details and printing that. The second feature truly is for ease of access. Have you ever used a NFC card reader? ApplePay, GoogleWallet, Ingenico payments, \"bump,\" etc are all examples of NFC payments (it stands for Near Field Connection). Your card chip also has this feature. Card security has been a moving target for years now, and it's true that the EU has been using chip cards for many years. Source: I am an ecommerce credit card fraud consultant.",
"You must be in the USA. Everywhere else in the world graduated to chip and pin a long time ago. As someone in one of those countries, the swipe reader in the parkade at work gives me more grief than every chip and pin reader I deal with put together. The PIN pad is about the same speed as signing: waiter enters the amount, you enter the tip and sign or enter your pin. I don't see much difference there. That said, if you think chip and pin is too much work, you're going to LOVE tap. It improves security by using a challenge mechanism. Instead of just a few static numbers, the card contains tiny little Engima machine with a secret code. The CC company provides a random number which, along with the pin is sent to the card. The card generates a new number from that and sends it back to the CC company. If the reply matches the expected answer to that challenge, then the transaction is authorized without ever revealing the secret code or the pin. Tap works in a similar way but without the pin. This is more convenient and arguably more secure but it does mean that anyone can tap the card if it is found or stolen.",
"Two-factor authentication. Which is worth a brief explanation, since so many people don't really get it. There are three ways that you can prove that you're you: * Who you are. (Your looks, your signature, your fingerprint, anything unique and recognizable about you as a person.) * What you know. (A password, a combination, your mother's maiden name, anything that a total stranger wouldn't know.) Or ... * What you're carrying. (A key, your cellphone, anything that only you have.) So think of the card number as a user ID and the PIN as your password. (\"What you know.\") How can we add an extra layer of security to that? Answer: public-key encryption. Which is some fancy math that lets you break a password into two parts; anything scrambled with one half can only be read with the other half, and vice versa. So when the card was manufactured, a public key/private key pair was created and the card got the public key and your bank stores the private key; your half of the key exists *only* in memory on that computer chip, it doesn't get stored anywhere else. So if your half of the password is used to encrypt the \"authorize this purchase\" message, and it gets correctly decrypted at the other end? That's proof that whoever is making this transaction is holding a card that only you should have. So if somebody learns your card number and PIN, they can't duplicate the card and use it, because they don't have the only chip in the world with your half of the encryption key pair. And if somebody steals your card, they can't use it, because they don't know your PIN.",
"The chip basically has an encryption key hardcoded in it. The server sends over a number, the card performs a calculation on it, and responds to the server, which verifies the response. The encryption key can't be directly read and copied. The information on the magnetic stripe is static and can be easily copied.",
"sounds like your chip system is not up to par yet. Using a chip is literally, tap and hold the card there for half a second. Then you put the card back in your wallet. That's how it works in Canada, for smaller purchases. Some places, you enter in a PIN, but it is only like 3 or 4 seconds longer. A couple of years ago, my friend from the US was sent by her company scout out the chip payment system and try to get customers to use their machines for payment. She then realized that everybody here already pretty much uses the chip payment and they would be trying to fight into an already saturated market. She also realized, they were really behind in adopting the technology."
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9no5pv | How do computers store information? And why is there an integer limit in computing? | Technology | explainlikeimfive | {
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"You don't need to know binary to understand this. You do need to understand two things, though: 1. Digits. Each number requires a certain number of digits. 545 requires 3 digits. 384271 requires 6 digits. Yes, computers use a different numbering system (binary) and will therefore require different numbers of digits, but the concept is the same: each number requires a certain number of digits. Also, for a certain number of digits, there is a maximum number that can be stored. For example, the biggest 3-digit number that can be stored is 999. 1000 is right out. 1. Memory addresses. Everything a computer is working on (*everything*) is stored in its memory. The way that a computer uses its memory is by using addresses. Instructions for a computer are like \"store the number 5 into address #1832\". Then later \"what was stored at address #1832 again? I need that now\". So whenever a computer is storing something in memory, or retrieving something from memory, it has to be able to figure out what address it should be using. Alright, so once you've got those two things understood, there's an unfortunate consequence of this. In order for a computer to easily/quickly figure out which address something's stored in, the address should be *fixed*. If we're doing an accounting program and we start storing the total in address #1500, it's got to stay there! Constantly moving stuff around in memory is a nightmare because you've got to have a system to keep track of where everything is, so keep all the addresses fixed. If your addresses are fixed, then that means the *sizes* (number of digits) must also be fixed. You've got to say \"okay I think my total will require a maximum of 10 digits, so let's use address #1500 through #1509\". If you later realize 10 digits wasn't enough, you're stuck. You can't make the number bigger (what if there's another number you're storing at address #1510) and you don't want to move things around, either. So you make a good guess as to what the biggest reasonable number you're going to need will be. Your addresses are fixed. The size of your numbers are fixed. For a number of a given size, there's a maximum number that can be stored there. Ultimately, that means your program's going to have limits on what kind of numbers they can store. There are systems to get around this. They're called [bignums]( URL_0 ). They have a book-keeping system to start off a number as being small, then grow it dynamically as it needs to get bigger. The book-keeping system is required because as the number gets bigger, it may need to be move to a new (free) spot in memory, so you need to always keep track of which address in memory it's moved to. Bignums aren't used all that often (usually only in specialized applications) because all the extra book-keeping makes performance quite poor.",
"All the letters and numbers we use have [corresponding combinations of 1's and 0's]( URL_0 ), and the computer stores the 1's and 0's on magnetic disks (hard drives) as magnetic pulses, on CD/DVD's as \"pits\" in the reflective film, or on flash drives as tiny electrical charges in the memory chips inside the flash drive. There's an integer limit because the processors and computer electronics are hard-wired to move data internally using 32, 64, and in some cases 128 wires at the same time, and processors operate with 64 bits of data (64 1's and 0's) at a time, so there's a limit to how big a number the processor can work with. Your computer can express bigger numbers, but the processor will have to break a bigger number into chunks it can handle, and work on each chunk at a time.",
"To better elaborate on the integer limit: on one bit (a 0 or a 1) you can store two possible numbers. Let's choose 0 and 1. Now if you have two bits, you can store twice as many as there are twice as many combinations now: 00, 01, 10, 11. These also happen to be the representation of 0, 1, 2 and 3 in the binary number system. Three bits allow you store twice as many (000, 001, ..., 110, 111) which can represent numbers between 0 and 7. In a decimal (base 10) system, whenever you add a digit, you can store 10 times as many numbers: 0-9 on one digit maximum, 0-99 on two digits maximum, etc. In a binary (base 2) system, whenever you add a digit, you can store 2 times as many numbers: 0-1 on one digit maximum, 00-11 on two digits maximum, etc. Computers store numbers in a binary (base 2) system, where 1 is represented by a jolt of electricity or a mark on a disk, and 0 is represented by no electricity/no mark. A 64-bit CPU does everything with 64-bit (64 digit) numbers. One bit can represent two numbers, and with every new bit twice as much, so we have 2\\^64 (2\\*2\\*2\\*...\\*2\\*2 all in all 64 times) possible numbers. 64-bit values thus can either store the first 2\\^64 integers, or more commonly the first 2\\^63-1 positive and 2\\^63 negative integers."
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9npdmy | Why is it when a radio has heavy static just walking close to it can make the signal stronger? | Technology | explainlikeimfive | {
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"Because you can act like an antenna for the radio. Try holding the antenna and moving your arms around. Or you could be blocking a source of noise that is interfering with the radio signal."
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9nrd2v | How does an iron lung work? | I was reading up about polio and read that many children ended up in iron lungs to allow them to breath "normally". What exactly does the iron lung do to allow the patient to breath normally? | Technology | explainlikeimfive | {
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"Your head is outside an airtight seal in the iron lung, so only the rest of your body is inside (generally, though at least your chest) & #x200B; The iron lung alters the air pressure in the chamber. If the force of the air pressure in the chamber is less than the pressure in the lungs, the lungs seek to expand to correct the difference and will cause the person to inhale with a type of vacuum force, really. When the pressure in the chamber then alternates to exceed the pressure of the lungs, it pushes down on the lungs with the increased air pressure, and causes the air to flow out of the lungs. & #x200B; It was a surprisingly elegant invention considering how much more invasive methods such as breathing tubes are with risks of infection, they aren't ideal for long term use. & #x200B; & #x200B;",
"Try inhaling right now. What you are doing in order to make that happen is a band of muscle in your torso called the diaphragm is pushing down on your organs, expanding the volume within your rib cage which inflates your lungs. Think of it sort of like a plunger in a syringe being pulled back, it causes things to be pulled into the resulting cavity. When you exhale the diaphragm is pushing upward to force the air out, again similar to a plunger in a syringe pushing out the contents. People who have had polio can be paralyzed including the diaphragm. Their brain cannot tell it to inhale or exhale meaning they would suffocate. What the iron lung does is increase or decrease the pressure within the chamber in which their torso and body resides. This pulls air into their lungs and pushes it out, replacing what their diaphragm otherwise would do. Simply put it breaths for them.",
"Good question considering the comeback of Polio in the years to come, with all the anti-vax talk going around..."
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9nrer9 | How do old songs like Message in a Bottle or TV shows like Friends get remastered when the equipment itself was used during the time it was recorded or filmed? | Technology | explainlikeimfive | {
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"The studio recording equipment, eg reel to reel tape and studio cameras make a much higher quality first generation copy of the source material. It's the mixing process and delivery formats that suck. Digitize the source material and re edit using modern equipment, you then get something that looks and sounds better on today's consumer equipment."
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9nso43 | How does this faster than light camera work? | They built a camera that records a single photon of light. How does this work? Why couldn't they do it before? URL_0 | Technology | explainlikeimfive | {
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"What is special about this camera is its shutter. First of all the shutter speeds can be set to extremely short times. This is done using fast spinning rotating shutters. However no camera can capture enough light during the short shutter time to make any meaningful image from. So instead they use multiple exposures to bring up the brightness. This does require the action that is being captured to be repeated in sync with the shutter. What you are seeing is not a single light pulse but rather billions of light pulses which have been synchronized with the camera shutter so that it looks like a single light pulse.",
"They combined an existing technology \"streak cameras\" with a beam splitter and a second camera to get a slower and cleaner picture. So what is a streak camera? Well firstly understand that, Movies are really series of photographs, each taken a small amount of time apart. The problem with light is that once you have taken the first picture, the light has moved on so fast it is no longer in the frame of the camera. The solution is to fire a second piece of light identical to the first, and take its picture a tiny fraction of a second later on the path the first bit of light took. Repeat and repeat, then combine all the pictures to make a movie that looks like 1 piece of light, but each frame is an image of a different piece of light, which is doing exactly the same thing all the others were. Now the trick these guys did is taking the same light from the experiment and split it off into both the streak camera and a new fangled static camera. The combination of the 2 images got them a highly detailed movie",
"How do you take a picture of a single photon? Isn’t a “picture” generated by sensing photons that hit a sensor? A camera should only be able to “see” light that comes through the shutter. If there is only one photon, the sensor would only ever get a single hit, and only if the photon was aimed at it. What am I missing?",
"> this faster than light camera Nope. Nowhere in the article does it say \"faster than light\" . > They built a camera that records a single photon of light. Nope. Nowhere in the article does it say \"single photon\". > How does this work? Why couldn't they do it before? It sounds like the main new thing is that they have two very different cameras filming the scene, one that is super fast but has very bad resolution, and one that has better resolution but is slower, and post-process the data from both to get a video that has both a ridiculous number of frames per second and a useful resolution.",
"It's not faster than light... what makes you think that? It's just a camera taking a lot of photos very quickly. There's nothing that special, this photo is a few years old actually, it's been posted to reddit several times in the past.",
"This is melting my brain. I always believed in order for a camera to record something light enters the camera. How is it able to capture a single photon from the side if that photon isn’t entering the camera. How can we see any photon at all unless it’s like seeing a ball as it’s about hit your face.",
"It seems that there are quite some explanations of the older, multi exposure technique. This article is on a new technique however, which uses only a single exposure. I tried my best to figure out what they where doing by reading the article, the paper, and looking at the graphics in both. I'm only a masters student in physics, and I don't have much specialisation in Optics, so I might be wrong. With that disclaimer out of the way... They use a normal CCD camera, much like the one in your smart phone, to get the \"static background image\" of the scene they are studying. This image will provide them with the spatial information of what they are looking at, even though it is far to slow to truly capture the movement of the light. To capture the movement of the laser pulse, they use a second camera, as so called streak camera. This camera, based on the graphic in the article, uses a phosphor screen to convert the light from the laser pulse into electrons, which are then accelerated and deflected by a varying electric field. This serves, in a way, to exaggerate the motion of the light pulse (the light pulse enters through a small slit, so as the pulse moves in the scene, it hits a different part of the phosphorus screen, and that change in where the electrons are freed from the screen by the photons, is than exaggerated by \"shaking the electrons further out\" in the electric field). This then leads to the electrons creating a streak on another CCD camera at the end of the streak camera, and is probably where the name comes from. The streaked image sacrifices the spatial information for temporal information (it doesn't so as nicely where, but instead better shows when), whereas the normal CCD still has all that spatial information. Due to the way it is done, however, you can't just add one and two together to get the full image. Rather, they use complex optimisation techniques, in which they use some very complex mathematics and a computer to find out which reconstruction (i.e. the imaging of the scene) best fits the data they captured using the two CCD cameras. Now I might very well be wrong, but I think at least that this is the essence of the new technique.",
"If you have 2 cameras, one takes a picture at .5 seconds, and the other takes a picture at 1 second. You took 2 pictures in 1 seconds. 2 pictures/second. If you have 10 trillion cameras, and have then all go off at specific, unique intervals within the same second, you took 10 trillion pictures/second.",
"I am not an expert by any means, but I do have some (very little) experience with scientific photography. So I'm going to give my guess at what's going on here: take it with some salt. In this experiment, they used two types of cameras. The streak camera has been adequately explained by other comments: it takes carefully timed pictures of multiple pulses then stitches them together to look like a single pulse. The other camera they used was a \"static\" camera. This wasn't explained very well, but I believe that what they meant was a camera that took a single photo of the entire length of one pulse. Ironically, this would appear as a kind of streak across the photo, like if you took a much slower picture of someone running across the frame. This photo by itself wouldn't be able to tell them much, because they wouldn't know which part of the photo happened at what time. However, they used something called a [Radon transform]( URL_0 ) (actually probably an inverse Radon) that can convert the smear of the static image into the actual shape of the light pulse. I believe that in order to properly calibrate it, they used the streak camera to get the general position of the light pulse at each point in time, and then were able to get the more detailed resolution from the transformed static image. So at an ELI5 level: they used the movie from the streak camera to turn the static photo into a movie itself, and then used that to measure the light pulse in detail.",
"It's because it isn't in a vacuum. What you're seeing is atoms in the air being excited from their ground state. It's essentially absorption and reradiation. This wouldn't be possible in a complete vacuum as there is nothing to scatter or absorb/reradiate the light. Photons are virtual particles and there isn't actually anything \"travelling\" between the source and interacted receivers; there's just a source being excited in some way and something that is in the \"path\" that is affected by the excited source that reacts after some d/c seconds later (where d is distance, c is the speed of light). In the video that was captured, you're seeing pockets of air absorbing/reradiating or scattering the \"photons\", meaning they're atoms in a direct line with the excited source. It's equivalent to shining a laser in a dark room and seeing the sparkly line that's drawn. You wouldn't see the beam at all were it not for dust particles reflecting some of the light."
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9nvjxs | Why do magnets "die" after a while of being used? | Technology | explainlikeimfive | {
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"Imagine the atoms in a magnet as little arrows. When manufacturing magnets, all of the arrows are arranged In one direction. This is done because it makes the arrows useful. ⬅️⬅️ ⬅️⬅️ These arrows don't like to all go in the same, linear direction. This is because they don't like their tips touching, or even getting near each other. As you can see, when they are all going in one direction, the arrow tips are very close the ones above. The arrows don't like this, and only want to be near the end of another arrow. This makes the arrows unhappy, so they become unstable and want to move. When the arrows are in a position they enjoy, they become happy. When they are happy they are stable and don't want to move. ↙️ ↖️ ↘️↗️ Because the arrows are so closely packed it is hard for them to rearrange in a way that makes them happy. One thing that makes this easier is when they are hot. This gives the arrows the energy and wiggle room they need to point at something they like.",
"Magnets actually are sensitive to a whole lot of things. External magnetic fields can demagnitize them. Shock or vibration (think beating with a hammer) can demagnetize them. And most importantly, heat will demagnitize them. The common grey 'ceramic/ferrite' magnets you might know from your fridge magnets are good only up to 450F. It's worse for neodymium magnets. They're much stronger than ferrite magnets and used in everything from powertools to electronics nowadays, and they will get damaged already at a comparatively low 160-170F."
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9nw4oe | Why are Disneyworlds 3D "movies" so much better than movie theaters imax3D and RealD? | Technology | explainlikeimfive | {
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"Normal movies are shot to be viewed in both 2D and 3D, this results in some compromises and relatively limited usage of 3D Disney knows that the movie will only be shown in 3D in that specific venue so they can specifically cater it to 3D and where the audience will be located which lets them achieve much more striking results Many modern 3D movies are also shot as 2D and then 3D'd later which results in rather disappointing 3D. Avatar was the first big 3D movie and it make fantastic use of 3D and was as striking as the Disney \"movies\" are, we really haven't seen another film that has made as good of use of 3D in the 9 years since Avatar released unfortunately."
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9nwk7j | How does a button click captcha work? | Technology | explainlikeimfive | {
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"You mean reCaptcha? It tracks mouse movements from right before the button is pressed. Humans move the mouse unevenly and somewhat erratically, while bots move the mouse very smoothly.",
"Clicking a recapatcha2 box takes information about the user's mouse movements at the time of action, and given information about website's owner's tolerance for bots, the recent activity from that source, and other information, makes a decision wether or not a test is needed."
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9nwmca | How exactly was DNA used to catch the Golden State Killer? | Technology | explainlikeimfive | {
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"DNA is a great tool in forensic analysis of crimes but is useless in identifying you if your DNA does not already exist in some form of database that police have access to. Having the best possible DNA sample available doesn't matter if there's no match for it in the database. There's been a proliferation recently of services that allow you to submit your own DNA for the purposes of matching you with distant relatives or determining your ancestry and the like. Investigators uploaded DNA samples from his crimes to one of those databases which identified a pool of related people and constructed a family tree based on public records. By investigating those people and matching them against the profile they had built about the suspect (based on behaviors and patterns and psychology), they identified the suspects that best matched their profile - then got a sample of their DNA and matched them against what they had and so identified their killer."
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9nx6mj | Why do objects in old cartoons that the characters interact with have distinctly different textures, colours, brightness, saturation, etc. than the background? | Technology | explainlikeimfive | {
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"Because they're drawn separately on different cels. In old cartoons, a background cel would be drawn and colored, and the foreground cels, containing everything that moves and is interacted with, are drawn and colored separately as well. The cells were stacked and the entire thing was filmed, one frame at a time.",
"I think it's because the background is drawn once and used many times but those objects are drawn for the specific episode."
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9nxasa | how do vinyl records work | Technology | explainlikeimfive | {
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"A vinyl record has a single groove running in a spiral from the inside to the outside of the disc. That groove looks smooth to the unaided eye but if you look closely enough you'd be able to see that it's actually jagged, with the interior walls moving side to side and up and down, while the groove's outer walls (think of it like a canyon) remaining stable and straight. The variations of the interior of the groove are transferred to the needle (or *stylus*) as it travels through the groove. The vibrations move the needle around, and those movements are picked up by a tiny electromagnetic system- either the needle has a tiny magnet on it which goes through a tiny coil, or the needle has a tiny coil on it which goes through a tiny magnet. These are called *moving magnet* and *moving coil* systems respectively. This motion of a coil and magnet creates a tiny current which is an electrical representation of the signal encoded in the record's grooves. The signal is very small, but when amplified and cleaned up by a stereo system, is sent to speakers which produce the sound waves you hear. Mono records record only one signal which comes out of both channels. Stereo records record one channel on each side of the groove, and are more complicated to reconstruct the sound, but the basic principle is the same."
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9ny7tl | What do the specs on my PC mean? | Technology | explainlikeimfive | {
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"> HP Pavilion Desktop, 590-p0066 Just the name > Intel® Core¿ i5-8400 The name of the CPU (the \"engine\" of the PC). Tells you about how powerful it will be on most applications (i5 8400 is pretty decent and good enough for even the newest PC games) > 12 GB DDR4-2666 There are 12 Gigabytes of RAM (pretty much, depending on what you are doing). DDR4 is the \"generation\" of RAM, DDR4 is the newest one available. 2666 means it is clocked at 2666 Mhz, which basically also gives a hint on operating speed of it. 2666 Mhz also is pretty good. & #x200B;",
"All different things. Generally, how \"fast\" and what model the components are. I put \"fast\" in quotations because software/hardware performance isn't an easy thing to measure with a number. Clock speed of a processor, and amount of memory aren't the only things that matter (especially true for the processor). My opinion, is that you need to run practical tests of exactly what you're going to do, for example game frame rates. There should be benchmarks out there. & #x200B; You run as fast as your slowest component. Finding where things get slowed down is the name of the game. Intel is a processor company so that's your CPU. Think of the computer as a programmable calculator. The calculations run through the CPU, the RAM is data available to the CPU, the hard drive is for bulk storage of data. It helps to know what you're trying to do. Games are very much driven by graphics cards; think of that as your main part for games, the other components need to be good enough not to slow that down. & #x200B; There's lots of numbers that matter for CPUs, they're quite complicated, but the most important thing these days is how well they're designed. RAM is needed to prevent accesses to the much slower hard drives. You want enough of that, so you don't run out; any additional RAM is pointless. Additionally, RAM speed is important (seems like you have a modern type of RAM). If you're not running games, the single thing that will increase performance the most is the hard drive, and going with an SSD (assuming decent CPU and memory, which you have). This is because you'll be constantly pulling data out of it, which takes time. It helps a lot to know what you're doing. Sounds like you have plenty of RAM and CPU power, the only question is GPU, if you want to play games. Breakdown: * HP Pavilion Desktop, 590-p0066 - Model of desktop * (good processor) Intel Core I5-8400 - CPU 6 core, 6 thread, 2.80 GHz, 9 MB Cache * (plenty of modern RAM) 12 GB DDR4-2666 * (what kind?) Hard drive, GPU"
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9nziye | Why printers are so consistently troublesome to use? | Technology | explainlikeimfive | {
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"Their failure rate is lower than you think, it's just that you don't think twice about it until it does fail. So it feels like it fails whenever you want it to work. Also, let's think about the internals of a printer. Lot of moving parts and a fairly complex architecture. There aren't many machines in your home that are mechanically more complicated than a printer. And the first rule of engineering is that every moving part, every extra layer of complexity, drastically raises the chance of something not working. You're used to things working more often because hardly anything else in your home has as much mechanical complexity as your printer.",
"Are you talking about a cheap $100 printer from Staples or a $2000 printer with a service agreement from an authorized printer dealer? Also, I have seen end users abuse the crap out of printers. They'll be placed in poorly ventilated areas, paper will be loaded improperly, toner will be jammed in, doors will be slammed shut, paper jams will be ripped out like a band aid being removed. Sometimes there are mechanical issues that get ignored regardless if an error light is on and people's remedy for that will be to physically abuse the device. And if the printer is connected to the network, there are network issues as well that 99.999% of \"IT people\" will blame on the printer without batting an eye."
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9o1xxa | What is NAT and why does it make playing with friends a pain in the butt on consoles? | What's the point of it? It's some kind of safety measure all I know. Rainbow Six: Siege had it awhile ago and it was impossible to play with friends with different NAT types. Ubisoft then removed it and you could play with friends no matter what's their NAT type. | Technology | explainlikeimfive | {
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"Every computer that connects directly to the internet has an address, kind of like your house has an address. When your computer talks to another computer it gets the other computer’s address and sends data there and includes its own address as a “return address sonthe other computer knows where to send information back to. The way internet addresses work there’s a finite number of them and about 22 years ago we started running out. One solution was NAT. Some addresses were reserved for private use and instead of every computer in your house having a public address (an address that wasn’t private) ISPs would allocate one address to each customer which would be used for their router and the router would give each device inside your house a private address. Now, remember when I said that when your computer sends data it puts its address in returns address part? Now your computer is putting its private address there. The router translates this to its own public address using Network Address Translation. The pain in the butt is that this only works for the outer envelope of the message. There could be parts inside the message that says, “Let’s play Rainbow Six together, connect to my PlayStation at this address...” and the router doesn’t know anything about that and can’t translate it for you. There are some things that can help with that but it depends on the developer to do it and get it right and everyone’s router to play nice.",
"Network Address Translation (NAT) exists because the internet is still largely IPv4 which is 32 bit, and with 32 bit network addresses you can only have about \\~4 billion addresses or so, I forget the exact number. Since the amount of internet addresses (IP addresses) on the internet is so finite, most homes only get 1 network address on the internet, which must be shared between all your networkable devices like computers,phones (when they are on wifi), consoles etc etc. So your router will create a *sub* network which lives only on the *local* interface of your router. Like [192.168.0.50]( URL_0 ) for your computer, and maybe [192.168.0.51]( URL_1 ) for your console etc etc. When one of your devices makes a request to the internet, your router must *translate* the local address to your (1) internet address and vice versa when the request result comes back. But if you are hosting a game, or acting as a server in some way, your router needs to know where to send that unsolicited traffic. So you setup a NAT rule to tell the router, hey, when a packet from the internet comes in and it's on port 6969 (whatever port your game/application is using) please send that traffic directly to IP address [192.168.0.51]( URL_1 ) (the local address of the computer I am hosting minecraft on (or whatever)). If you don't configure the NAT rule on your router, your router won't know where to forward that unsolicited traffic to. & #x200B; Edit: Just realized this is explainlikeimfive. Let me try again. The mail man comes to your home address (Internet IP address) to deliver a letter. The name on the letter is \"Billy Smith\" (port number). The name on the letter lets the people in the house know who the letter should be given to. Billy Smith receives the letter, reads it, and decides what to do based on the information in the letter. When Dad (the router) opens the door, he knows that all letters that say \"Billy Smith\" on them should go to Billy. This is the NAT rule.",
"Its a way to separate your network from the big internet and get more IP addresses by rewriting net connections.",
"The easiest NAT analogy I can think of would be a building with a mail room. The building has an address, and then each room within the building has a different address that mail room workers use to deliver the mail to the correct place. When someone sends a message, it is sent to the building address, then the mail room workers need to figure out to which room it must be sent using an internal address. In this analogy, the building represents your home network and all of your gaming devices, and the mail room is your router. The mail would be packets of information arriving from the game servers. Without a system to determine where the mail needs to go inside the building (NAT), the mail room workers (your router) dont know to which room (device) the mail (data) should be sent once it arrives at the building (your home network). The post office (game servers) know the building address (your WAN IP), but not the internal addresses for each room (your LAN IPs)."
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9o330k | What does it mean to "train" an artifical intelligence? How are they "taught" or "self-educating"? What exactly happens when they "learn"? | Technology | explainlikeimfive | {
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"For example when you want to train an AI to learn to decide if there is a kitten in the picture. You have a neural net that in the beginning doesn’t know anything so you give it multiple pictures of different cats with different backrounds (in reality they use up to billions of pictures to train). The AI now has to decide whether there is a cat in the photo and every time it‘s wrong it changes it‘s algorythms. If it‘s right nothing changes. What that is called is a neural network. Every neuron in this network is supposed to determine a specific area of the photo(i.e. its ears or whiskers etc.). And after every wrong attempt you tell which neurons have to rearrange until it has a near perfect detection rate, which often takes millions and millions of tries, until in the end it‘s nearly perfect. You can use this principle on every kind of detection from street signs to number plates to facial recognition. I‘m sorry if my text isn‘t grammatically correct it isn‘t my first language. If I made any errors in content please point them out so I can correct them.",
"They learn from experience. What they tend to “learn” is deviation from standards, and either how to avoid or follow those. Say you want to develop an AI to engage in conversation, you can feed it the back-and-forth of 1,000 conversations, and it’ll get pretty good at understanding how humans talk to each other. On the other hand, if you want to develop an AIops to see if a user in your organization was hacked, you would monitor their computer activity for as long as you have data for, and if they’re seen doing something suspicious, or out of the ordinary, the AI would alert upon it. We still have a long way to go, but AI is a fantastic tool!",
"Say you want an to play a simple game. It shoots a cannon at a target. We measure how good the AI is by how far from the target the cannon ball ends up. Now to train, you have the AI play this game a bunch of times. Each time, it changes some little bit of it's behavior. Behavior that gets it closer to the target are kept, and ones that end up farther get thrown away. You repeat this either for a set number of times or until the AI can consistently get a certain score. IRL, this is usually done by making a bunch of clones of the AI at the beginning. Each one has that little random change (a mutation if you will) and they all play the game. The ones that did the worst \"die\" and are deleted and the best ones become the parents of the next generation.",
"My attempt at a true eli5: Basically, an AI is a system that can see the differences between things you show it. Some are crude and can only notice a simple difference (i.e. that a number is even or odd), others are more complex and can notice many differences (i.e. that an image is a picture of a cat or not). To \"train\" the system, you just give it a long list of items paired with their correct \"answer\". After you show it a big enough \"cheat sheet\", it can get really good at correctly guessing the answer when you show it something it hasn't seen before. When they do this \"learning\", the machine is storing a bunch of information about whatever its goal is. A human can do something similar (i.e. learn that cats have ears and whiskers and tails, etc), but for the AI, it could just be like... If the top part of the picture has a blob of pixels that look kinda like this blob I saw before, it is more likely to be this \"cat\" thing."
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9o4vq0 | Why do some programs, after downloading or changing a setting, need a restart? | Technology | explainlikeimfive | {
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"When a program starts it stores a load of information on your computers memory, that makes it more efficient than constantly reading from the program files. When there is an update, the code of the program changes and some of the configuration as well, this means the memory on your computer needs to get all of this information again to be able to function properly."
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9o5uke | Printers are known for being horrible, breaking down randomly and having many errors. In this day where every piece of technology is getting better and better, why are printers still so bad? | Technology | explainlikeimfive | {
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"In defense of the poor printers, most do a pretty good job in a high-abuse environment. Printers have some very hot parts, think a hot light bulb. They have some staticy parts, think scruffling across a carpet in dry weather amd touching a door knob, they have high voltage parts, they have wheels and gears to move tightly stacked paper and they have to handle a lot of very powdery very sticky stuff called toner. Most printer problems are caused by one or the other of these things either being overworked, worn out or just trying to cope with an environment they don' t like. The staticy part doesn't like to work when it is humid. The tightly stacked paper doesn't like to separate into individual sheets when it is humid either. The if the staticy part or the high voltage part is just a bit off the powdery sticky toner can start to build up on parts it doesn't belong, the the hot part can make it melt and stick. If the wheels or gears get worn the paper may not get pulled through properly. Most printers will work for years trouble free if you use them within their specs. Problem is almost all businesses buy the cheapest printer they can, and then unleash heavy printing demands on the users. That leads to exactly what you describe, poor reliability.",
"Printer companies make money off of broken printers and ink. Most warranties for printers are short and printers are precision designed so they break after the warranty. Most of the time, printers don’t even break, they just sometimes print something wrong or have a small error and then force you to buy a new one. Printers also lie about the amount of ink in the capsule to get you to buy more. Printer companies also go by a “give them the handle, sell them the razor” ideology, selling you the printers for very cheap but making the ink an exorbitant price. Because of this, printer ink has literally become one of the most expensive liquids in the world. Austin Mcconnell did a video on this. I can share you the link if you are unable to find it."
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9o6gcz | How can a bunch of text characters crash a PS4? | Technology | explainlikeimfive | {
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"Crashes typically happen when a program is caused to enter a state which is unexpected by the programmers, resulting in incorrect behavior such as infinite loops or the attempt to execute instructions which cannot be performed. In the case of a message causing a system to crash it might be due to how certain kinds of text are produced. Different languages use different characters which are stored in packages. When a message is received it contains instructions on what packages of characters are to be loaded so the message can be displayed, and it is possible that there is an error somewhere in loading one of those packages where perhaps it does not exist, or causes other problems. For example there are some languages which attach certain symbols to other characters, such as above or below them, to modify their meaning. The character packages contain instructions for how a symbol can be attached to another character, and sometimes you can even attach more than one symbol to a character, or nest them so a character has a symbol attached which itself has a symbol attached. A malicious user might then craft a message that has thousands of symbols attached to one character which results in the system trying to display something which the programmers never anticipated would be attempted, leading to unexpected behavior and a crash."
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9o7yq5 | how would a cell phone react in space? | Would you be able to take a selfie? Would they be able to capture audio? Would internet work at all? | Technology | explainlikeimfive | {
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"It wouldn't have signal but it would do all of the non-phone tasks just fine though it would overheat after a while. You're a wee bit out of range of cell towers being at least 100 km up, but there is WiFi on the ISS. It's super slow but its WiFi nonetheless. Pictures work just fine, a cell phone uses the same technology to capture pictures as the cameras we put on probes and satellites If you were somewhere with air then yes, it could capture audio; but in the vacuum of space no one can hear you scream",
"While I’m neither an engineer, nor a scientist of any sort, some things I can tell you with about 95% certainty is that you wouldn’t get service of any sort, as cell phone towers peak out at about 45 miles, and your screen would shatter (LCD stands for LIQUID crystal display, and the liquid would freeze instantaneously)"
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9o871q | Why don’t they make paper straws the same way they make paper cups? Would seem to solve the issue of them getting soggy. | Technology | explainlikeimfive | {
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"Unlike the cups which the liquid only touches the coated waxy surface, the straws would have to be coated on the inside, outside, tip, and the seam. I imagine this would be harder to do and make them rather expensive.",
"I would imagine paper straws wouldn't have the rigidity to keep from closing from suction. Drinking water would be like drinking from a thick milkshake out of a thin straw, constantly collapsing from the pressure."
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9o8ecu | What’s so special about the UNREAL ENGINE? There are so many video games that seemingly are powered by UNREAL. | Technology | explainlikeimfive | {
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"It's an engine with a lot of features already built in, instead of having to make one of your own (which is very expensive). IIRC, the makers of the Unreal engine offer a deal where they just take a cut of your profits as payment for use of the engine. So, little to no upfront costs, no maintaining the engine (the Unreal team does that), you just build on it and in return fork over a percentage. Pretty win/win.",
"Designing and building an engine for a game takes lots of money, time and talent. Many developers opt to license the Unreal engine because it is already built, has people that can help solve problems, and is proven to work on all systems on many different genres.",
"Software is a *lot* of work to write. The total amount of code that goes into a modern game as well as the tools used to develop the game is huge. In order to save time and effort, game programmers keep around various libraries of software that can be re-used in other games. As these libraries of software and tools build up, they're sometimes polished into an actual product in of themselves. WWise is a common audio middleware. Havok a common physics middleware. Blink a common video player middleware. Scaleform a common UI middleware. Just like Unreal, you'll find those names plastered on boxes too. All it means is that is cheaper and easier to license software and developer support from another company than to build all the software yourself.",
"The Unreal engine is very attractive to indie/small studios. When choosing an engine, studios have to weigh the pros and cons of each. Cryengine, for example, requires quite a bit of legal paperwork and usually a large cash payment up front. Indie studios who don't have a lot of capital to work with (and don't want to take financial risks yet) are fairly put off by this. Making their own engine is usually out of question as they have neither the experience nor the money to make an engine in-house. Unreal engine offers a special system in which the devs can use the engine without upfront costs. The deal is that they have to share a percentage of the profits with Unreal. This is attractive to new studios because there is far less inherent risk. If their product doesn't sell well, they don't have crippling debts from the engine purchase."
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9o8lwe | What is Raspberry Pi and what can you do with it? | Technology | explainlikeimfive | {
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"text": [
"At it's simplest, it's a inexpensive and weak computer (with an ARM CPU) with the essentials and a few general purpose pins that can be controlled/read through software. As for uses, it's up to one's imagination.",
"It's a simple computer. If you need a computer to run a simple program but dont want to waste a whole desktop for that then a raspberry pi is a simple cheap solution. It's also very good for getting kids interested in coding."
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9o97wg | How is it that Google became a much more popular search engine compared to URL_0 , altavista or even yahoo when they basically do the same function? | Technology | explainlikeimfive | {
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"Google got much better results. The older ones, back then, often didn't do so well and you had to try a few times with different terms to get what you wanted. It took a bit of skill to find what you wanted sometimes. I was pretty good at it and people would sometimes ask me for help in finding obscure things. Wikipedia wasn't around (or was kind of obscure) which also made things more difficult.",
"Because they didn't do it the same way in the past. On the one hand there is indexing. Google found pages automatically with their crawler. Yahoo by comparison was largely curated - sites were manually added in various categories. Yahoo literally had a big list of categories like Cooking or Space and you could click a link in that list to see a further list of \"all\" of the sites on the internet in that category. The other is relevance. Search engines like Altavista (the first search engine I used back in the 90s) relied exclusively on word matching. It looked for pages containing your search term and ranked them by how many times that term appeared on the page. Pages would often fool search engines by simply listing hundreds of keywords in hidden text at the bottom (and some pages were just a huge lists of keywords designed to draw hits from search engines). Google started with an algorithm that took into account what pages linked to which other pages. So if 3 pages with your term linked to the same page then that page was given a higher ranking.",
"Because Google did it better. In the early days of search engines, there were fewer crawler bots (as in, programs that \"crawled\" the internet, clicking on links and capturing contents on pages). If you wanted your page to show up in a search engine, you had to submit it yourself. This mandated having to find the right category and give it the right tags and a good description. Sort of like filing it away in a filing cabinet. If you filed your page about beekeeping away in the beekeeping shelf, then it would get listed when someone told the search engine, \"Hey - go get me info about beekeeping.\" Most engines would pair this with another method: keyword matching. If you searched for \"beekeeping suits\", it would check your description and your page contents for how often the phrase appeared and then order them in your results according to that, under the assumption that the more times you mentioned beekeeping suits, the more relevant the page would be to someone who searched that. Both of these techniques did not work in the heydey of internet advertising. Ads work based on the number of eyeballs who see your ads, so owners of webpages with ads are encouraged to get as many unique eyeballs onto the page regardless of how long they stay. In the few years before Google, you'd see pages where they were \"filed\" under as many categories as possible, where entire lists of words were copied/pasted into the bottom of the pages or into the hidden < meta > tags in each page. Sometimes you'd search for something and the most relevant result would literally be nothing but a list of those words and ten banner ads. There were attempts made to try and curate the index and remove offending pages, but the internet was growing at full steam by this point and outpacing people's (usually volunteers) ability to keep up. In addition, Google rose when dialup was still the most common form of access to the internet. Search engines prior to Google were not big money makers (and search engines themselves still aren't; Google makes its money selling you ads). The big companies like Altavista and Yahoo were not immune to this and so they got into that ad banner revenue by trying to keep you on their sites and offering more than just search engines: news, email, games, chat, web page creation. [This]( URL_0 ) was Yahoo's front page in June 2000, when Google overtook it as the most used search engine. Compare this to [Google]( URL_1 ). Fewer links, fewer images. Much faster to load. Much more focused on *searching*. No extra services. Must less focused on \"browsing\" the internet and more emphasis on searching it (finding what you need as quickly as possible). Google also fixed the relevancy problem in a creative way: by crawling the web, Google would see how often pages linked to your page and that would determine its importance. It's since moved on from this algorithm, but it helped filter data more relevantly, which was HUGE when you were used to having to first figure out which of your search results were spam pages. And finally (and this is probably more conjecture than anything), prior to Google we treated searching for information on the internet like it was searching for information in a library: the design of search engines and organizing web pages into categories and subjects was akin to library classification. There was the expectation that you could narrow your search for information down by using the subject card catalog or finding the relevant Dewey/LoC call numbers (or, online, clicking into the right category) but you still had to then search through the books/pages at that location for the information you needed. Google was one of (if not the) the first web data companies to realize that it could use computers to not just act as repositories of data but also as processors OF that data and they created algorithms that sought to get you the information you were looking for in as few clicks as possible by learning from the data and learning from you. The pre-Google equivalent would be: if you wanted information about something specific and the library card catalog didn't just point you to the right shelf but to the book, the page number, and exact paragraph/line containing what you were looking for.",
"Because it did that function so much better than the others. Google stood out very quickly for giving you far better results.",
"The main reason I started using Google was that in 1998 or so they were the only engine that showed you the context of your search term's appearance on the page in the preview block on the search results page. All the rest just included the page name and some information about the domain and it was up to you to click in and work out whether the page was relevant or not.",
"I was around when google first came out. Before google, I would be using at least 5 different search engines, and digging through pages of results to find what I wanted. I was amazed when I first tried google, because I would find what I was looking for in just the first few results on the first page. It became the only search engine I needed.",
"In the 90s, the reason why Google became my preference was aesthetic as much as anything else: The opening page was simple the word Google with a single search bar. Nothing in the margins. No ads. Nothing more than a page with a search moment — just like being at the library searching their system. It was easy :) *bliss*. Now you start typing and they take you straight to options *disappointed*. For a long time, to me, Google felt like the Apple of search engines: Beautiful in its simplicity. (The good ol’ days...!)",
"Back in the day ASK was a good search engine and Altavista was probably my favourite. ASK worked best for simple searches with just single or double words. Whereas Altavista (and early Google) worked very nicely for people with a bit a programming ability to use AND/OR/NOT to narrow down their searches to specifics. I would say Google won the search engine war because: - You can type in complex questions like \"What is the tallest mountain in Europe?\" - Google has worked hard to generate a large variety of results - Google managed to cash in with the best advertising business model (allowing them cash to develop more features and allowing more aggressive business tactics) - they have been careful to allow adult searches while still being able to SafeSearch - they really pulled ahead once image searching began - they're the default search engine on most Android phones - Chrome became the fastest major browser (it's the first thing I install when I install a new OS)"
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9oc9yu | How does 3D Printing work? | Technology | explainlikeimfive | {
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"Many common machines (called FDM) are basically a glorified hot glue gun on robot arm, or lays plastic down and moves around while it cools. Then there are many other 3d printing techniques, but this is the most common and simplest",
"You submit a 3d model file to a machine then the machine takes the object and in most commercial printers lays down layers of plastic until it finishes building the model. There are other printers but most work in an altered form of this.",
"You design a 3D object in a computer program. The program then converts it into instructions for a 3D printer. The 3D printer heats up a plastic-like material and squeezes it out of a nozzle. The program tells the printer where to place the nozzle in order to construct the desired object. The printer prints out the object a layer at a time. When one layer is completed, the platform the object is being printed on moves (or the nozzle moves up) to printer subsequent layers. The plastic-like material cools and hardens very quickly, almost immediately after it comes out of the nozzle.",
"Depends. We have FDM printers which are the mosr current. FDM stands for Fused Deposit Material. They work by melting plastic and pushing the melted goop through a tiny nozzle while motors move that nozzle. It's an additive process that lays laywrs upon layers until the complete object is completed. Then you have SLA printers that use a laser in a resin bath to solidify that resin. You can find similar systems named DLP that will use a screen generating UV rays that will work the same way, by curing resin. SLA and DLP have greater resolution than FDM, but are usually more expensive and / or smaller. You also have to deal with chemicals that can be harmful. I don't know if the speed of printing is improved, but I suppose it does, at least for DLP as it's the full layer that is cured at once ans not just a tiny point. I'm typing this on mobile, please excuse typos.",
"Okay, this is something I'm pretty knowledgeably about! I love posts like this! Point is there's a lot of different ways. The most common and cheapest and most popular is FDM. FDM is fused deposition modeling. Basically what happens is that it takes a 3D computer render, typically in .STL file format. Then using a dedicated program for your printer you \"slice\" that image into a bunch of layers. The layer thickness is typically adjustable and is only limited by how thick or thin your printer can print a single layer. So for example if you have a 15cm tall knick knack you want to print, and your printer can print at 1mm thickness then the computer will slice it into 150 different layers. So the printer then extrudes the first layer. Then the nozzle moves up one 1mm and then prints layer #2, Them moves 1 mm up and prints layer #3. And it repeats that until it prints all 150 layers. Now there's all sorts of different 3D printing methods but almost all of them work on the same principal of having a thickniess of a printing layer, and going layer by layer. Stereolithography is another great one, it has some of the highest resolution, although the materials that can be used are pretty rare and expensive, and not that great for a lot of applications. It uses a resin and lasers to solidify the resin in the given pattern, although even within stereolithography there can be a decent amount of variety of how it works. Selective laser sintering or SLS is another one that is promising, because it can be used to print metals. But it is costly and has it's own challenges."
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9od8pq | How does electronic data storage work? | When I speak of data storage, I'm referring to anything that is used for storage purposes. For example, what differentiates the methods of storage between credit cards, CDs, cassette tape, USB drives, etc? I have always been curious about this kind of technology that we take for granted, as I was never taught how it works in school. | Technology | explainlikeimfive | {
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"The history of computer data storage is long and super interesting. Lots of people have had lots of interesting ideas about how to convert some observed physical phenomenon (like magnetism) into something that a computer can use. Some of the early computer were even designed with one type of memory, and then some totally different but better kind came along, and the computer would be retrofitted with the new memory. Credit card use a magnetic stripe. You might have made a little magnet as a kid: you take an ordinary needle, stroke it against a magnet, and it turns the needle magnetic. Well, it turns out that you can place a magnetic film on a long roll of \"substrate\" (usually plastic these days). The magnetic film is really a whole series of little \"islands\"; each island can be magnetized separately. If you \"zap\" one portion of the tape a jolt of electricity (technically: make a strong, directional electric field) it will magnetize just the islands close to the field. The little fields can be \"read\" separately. You can also put the magnetic \"stuff\" on a disk, and you get a disk drive, or onto a drum, and get a drum. Drums are long obsolete. CDs work totally differently. With a CD, you zap it with a laser, and burns a little pit in the plastic substrate. Or, the CD is made with a sort of dye solution, and zapping it with a laser simply turns the dye a different color. USB drives use what's called \"flash\" memory; it's fully electrical and uses little capacitors to hold or not hold a small electrical charge. And, over the decades, people have come up with dozens of other mechanisms. IBM once made a giant micro-fiche machine: you give it a bunch of data at once, and it would flash lights in a pattern at unexposed film stock. The machine would then automatically process the film and place it into a little niche where it could be read from afterwards."
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9odfuv | Cars have an “idle speed” where the engine still runs even without pressing the gas. What happens when you’re pressing the brake and completely still? How is the engine not harmed since it’s still running? | Technology | explainlikeimfive | {
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"Automatic transmissions have a fluid coupling between the engine and transmission that allows the engine to run at low RPM without transmitting much torque to the transmission. Imagine a propeller spinning, making the fluid spin, then the fluid makes another propeller spin. Manual transmissions disengage the clutch so there's no connection between the engine and transmission when you push the clutch pedal in.",
"The brakes only apply “stopping force” to the discs attached to the axels. The brakes don’t actually stop the engine.",
"In a Automatic transmission car think of the link between the engine and the transmission as a desk fan pointing at another desk fan. The one fan is powered as it is connected to the engine. The other fan is connected to the wheels and spins because of the airflow from the powered fan BUT you can easily stop it if you want. In a car the Torque Converter is these two fans and it uses a fluid between them instead of air.",
"It's either in neutral or park, or it's in gear with the clutch engaged (manual) or the torque converter engaged (automatic). In this state, there's nothing loading up the engine so it can spin freely. If you kept the brakes on and pulled the clutch out on a manual car, the engine would stall.",
"The clutch disengages the engine from the power train, physically separating the engine from the gears going to the wheels, so it just spins with no load on it. That's what happens whenever you're idling, breaking, or shifting gears. On a manual transmission, you do this manually with the third pedal. Automatic transmissions do this for you automatically.",
"In traditional manual transmissions, failing to apply the clutch pedal (and ideally shift the gearbox into neutral) as you come to a stop, will indeed stop the engine. You can put this down as an example of a \"stupid driver error.\" This also arguably works as a safety feature in case the driver becomes unconscious. Moreover, there's typically a safety interlock switch that won't allow the starter to work except when the clutch is pressed. This is to prevent damage to the starter or transmission. The clutch functions to couple or uncouple the engine output shaft to the wheels, and allows the engine to rotate freely at idle or if you're shifting. In general, you should place the x-mission in neutral when idling at a stop. Otherwise this tends to cause wear on the clutch plates. Automatic transmissions tend to have a fluid coupling and an automatic clutch between the engine output and the x-mission.The fluid coupling still transmits some torque to the x-mission when the clutch is unlocked. On the other hand, the clutch bypasses the coupling and creates a hard connection between the engine, the x-mission, and the wheels. The clutch is disengaged whenever the transmission control performs a gear shift. Tbis makes shifting much smoother and makes it not necessary to get of the gas when you shift, unlike a manual. Also, in idle this torque is fairly low. Modern ATs are electronically controlled, and are programmed to unlock the clutch at idle as well as during shifting. Because of the fluid coupling, this allows the engine to still rotate even when the wheels are stopped. This produces a low torque on the wheels which is why cars with AT's will tend to creep forward when the brake is released."
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9oea7m | Cubesort | How does cubesort work? I was reading about other sorting algorithms when I came across Cubesort, and I can't wrap my head around it. I know how other sorting algorithms such as Quicksort, Radix sort and Mergesort work. | Technology | explainlikeimfive | {
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"A standard balanced binary search tree (let’s say of numbers) has a root node (avalue at the very top of the tree that should be directly in the middle of our sorted data) with two branches. You compare your key to the root and go from there if it’s higher or lower. You keep comparing until you find your exact key or nothing. Each comparison cuts your search space in half. (O(log(n)) average time for non-ELI5) Cubesort is a two-dimensional array of arrays, so like a grid where each square is a hole you can put your numbers in. Say we use a 4x4 grid, or 16 holes. Your key is used on the x-axis to determine which column we can find it in. Then it is used on the y-axis to find the specific square. Within that slot (remember, grid of holes) is where we will find what we are looking for, if the value exists. In here is also approximately 4 sorted values to look at. Overall, 6 lookups for 64 spots (or O(log(n))) Why is this better than our binary search tree? We don’t need to keep pointers to the various branches all over the place. Some operations are also quicker (O(log(cube-root(n))) instead of O(log(n)) for a less ELI5).",
"When you have a bunch of alphabet blocks and want to sort them, you could sort them by placing one block, then either placing the next block before or after the first block, so that the order is always in one direction. But if you need to place the block before any others, you need to move each block, one at a time, to make room for the one you're trying to insert. It's not a problem for a small number of blocks, but would be really tedious if you had to move 20 blocks, one at a time, just to insert a single block to your ordered alphabet. What you can do, is check if your line of blocks gets a bit too long, then split it equally in two. Now, you compare your block to the start of each line of blocks to figure out which line the block is in, then you compare your block to each of the blocks in that line to figure out where to insert your block. That way you can avoid comparing all but the first block of each line, and when you insert your block, you only have to move the blocks after your block in the same line, not any other line, so that makes things much quicker. So that is taking a long line of blocks and splitting it up to make it more like a square. A cubesort takes things into another dimension. So instead of selecting line, then block indexes, you select plane, then line, then block index for determining where you insert your block correctly."
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9of2wt | What is the difference between OLED and QLED technology? Which is better? | Technology | explainlikeimfive | {
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"Okay, so OLED is a major update to traditional backlighting systems, in a similar vein as plasma TVs. They are called “self emissive” pixels which basically beans that each pixel creates its own light and color. So when the screen displays black, the pixel simply turns off. This helps immensely with the contrast ratio and color volume of the tv. QLED works exactly like a traditional flat screen in that it has some sort of back light which is then filtered through an lcd screen which creates its color. The only difference between a qled and a regular led-lcd tv is the use of quantum dots, hence the q. Quantum dots act as a secondary color filter to preserve color accuracy at high brightness. Samsung absolutely uses these incorrectly though, because they intentionally under saturate their color palate to appear brighter and more vibrant. TLDR - buy an OLED or a 900f",
"OLED is basically the same tech as AMOLED as used on mainly Samsung phones. Each pixel is self illuminating, therefore absolutely black is 'off', and really black. Its like having millions of individual LEDs for pixels. QLED is an LCD with quantum dots, which is an advancement over traditional LCD, however its still an LCD, which needs a backlight. This means black isnt absolute because no LCD can block out all the backlight. Each pixel either colours the backlight going through it, or tries to block it out. Generally they both create a great image, OLED has greater contrast because of the deeper blacks, QLED has greater brightness because the backlight can produce more light than the pixels of an OLED screen. Personally if used in a bright room id choose QLED, if used in the dark, or a darker room id choose OLED. In the dark you would see the backlight 'bloom' around a dark area of the image on a QLED TV, and viewing angles are slightly worse usually, but OLEDs dont have the intense HDR pop of a QLED, so the choice is yuors.",
"Don't forget oled can and does burn in and oled is more expensive. Buy what u can afford and what makes u happy. Edit: qled is also brighter if I'm not mistaken.",
"The way most digital screens work today is LCD - Liquid Crystal Display. Basically these molecules suspending in a fluid are made to align with or block light coming from a back light. Put red, blue, and green color filters over these controllable back-light filters, and when taken as groups they make up a pixel, where you can select how much green, blue, and red light comes out of a little spot. This is why blacks don't appear perfectly black - the backlight is still on, at full brightness. The black screen is just filtering the light as best it can by blocking as much as it can - which isn't 100%. QLED is an extension of the LCD system, where you have a back-light producing all the light, and then it gets filtered down into colors using Quantum-dots, which have some nice properties for producing specific colors. But fundamentally it's still a system with a backlight and filters. OLED by contrast is just having individual red, blue, and green LEDs making up each pixel. So instead of a pixel being controlled by how much light is filtered from a constant source, it's being controlled by just having the LEDs emit more or less light. To make black, they emit no light at all. So you get perfectly dark blacks because there's no light, rather than just maximally filtered light. OLED is especially nice for phones because they use less battery when you've got a screen that's mostly black - like reading an eBook at night. The phone is really only sending power to the ~5% of pixels you've got on that are spelling out the words. And each of those pixels are only consuming power commiserate with your brightness settings."
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9ohbsb | What are APIs and why are they useful? | Technology | explainlikeimfive | {
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"An API (Application Programming Interface) is a *standardized, documented* interface that allows one computer application to \"talk\" to another computer application. Others in the thread have given similar definitions, but they've missed the most important part: standardized and documented. Without an API, Application X has to directly integrate with Application Y. That works ... _until_ something changes in Application Y that breaks the integration. Then Application X has to update or re-do their integration ... _until something changes in Application Y that breaks that updated integration. And so on. Another way to think about this: the electrical socket in your wall is like an API. It's standardized and documented, so anyone building an appliance knows how to build a plug that fits that socket. That's like what an API does. Imagine if that *weren't* the case. Imagine if sockets in different houses were each different. Or imagine if the configuration of the socket changed every time the power company updated their infrastructure. That variability and unpredictability would make it *really* difficult to build something that could *reliably* and *consistently* plug into any socket in any home or business. By standardizing and documenting an interface, like a electrical power socket, a developer of ovens or TVs or vacuum cleaners or whatever have a stable interface that it can use to get electrical power from *any* socket. The standardization and documentation is critical to making the interface effective and efficient. That's the same thing that an API does except for the exchange of messages and data between one computer application and another.",
"API stands for application programming interface. It's a set of tools that let one piece of software interact with another one, either to retrieve data or to make something happen. For example, say you are making a Facebook game where users can play with their friends. To do that you need to know who their friends are and some basic info such as their name and profile picture to display in the game. You get that by sending a request to Facebook's API, which is usually an HTTP request including info like what info you want and an authorization token, and then the Facebook API sends back the info you want. It can also work the other direction. If the user gives you permission you can use API calls to post or create information by sending it to the website or software that way."
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9olkci | How does binary code translate into, for example, a 4k movie? | Technology | explainlikeimfive | {
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"Binary code is just numbers. Only instead of counting: 0, 1, 2, 3, 4, 5... you count: 0, 1, 10, 11, 100, 101. Both are exactly the same thing, just represented differently. Then, a movie is just a set of images. For a 4K movie you have 3840 columns by 2160 rows. Each pixel is divided in red, green and blue components, which normally has 8 bits for each. So you have a value from 0 to 255 for each of red, green, and blue. 0 would be black, 255 would be 100% red, green or blue. 128 would be 50%. A combination of red, green and blue mixes to create different colors thanks to the way our eyes work. In practice of course 4K movies are heavily compressed, as the space requirements for uncompressed 4K video is enormous.",
"You've got your movie file downloaded, on a disk or on a USB. Firstly, the video player will open it and detect the file format so it knows how to read it. Once open, it'll start reading the file data line by line. Each bit of data will represent a pixel in an individual frame of the movie, which is quickly (usually 24 times a second, or 24FPS for movies) updated with a new pixel. The file data is stored on the storage device as binary in its lowest form, so when it's reading that file it's reading all that binary data and making sense of it."
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9omr9m | How do television networks know how many people tuned in to watch a specific show at a certain time? | Technology | explainlikeimfive | {
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"They often have a number of people who fill in viewing diaries in return for a small payment. Extrapolation to the whole population, similar to opinion polls, gives the total audience. Other methods use recording boxes to work out what channel the tv is timed to over time.",
"Here is one strategy: A ratings company canvases a neighbor and finds houses that have the demographics they want to check. They look for a number of factors: occupants of the house, their genders, relative ages, occupations, tvs computers, etc. etc. etc. If the household agrees, they will install devices and software that can monitor watching habits. These devices and software will report back to the company. This information is then aggregated and used to determine viewing habits and derive ratings.",
"Building up on these responses, how do they avoid bias from small sample sizes/sample selection? & #x200B; (Thanks for the amazing questions, I've been wondering for a long time.)",
"In the old days, they used representative groups like the others described. These days, think about how television gets delivered. For TV coming in via a cable box, essentially it's the same as with Netflix/Amazon Prime streaming: you tell your cable box \"I want to watch the WWE network\", the cable box goes to the nearest server and says \"give me the stream for the WWE network, please\". That server keeps a record of which channel it sent to where, and for how long. In addition, there are tracking technologies that are really complicated, including ones built into smart TVs - they actually monitor the pixels of the display and can tell the content you are watching, especially if it has a special invisible tracking pixel included."
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9on7ss | Why does microwaving a pastry only take 15 seconds to get it piping hot but really watery things like soup can take several minutes? | I thought microwaves agitate water, so it would seem to me that the higher the water content the faster it heats. | Technology | explainlikeimfive | {
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"Q=mcp(deltaT). Thats equation for heat transfer. Water has a really high heat capacity (cp) and can be pretty dense (high m). It makes the amount of energy required to raise the temperature pretty high. So it does heat up water specifically, its just pretty energy intensive to heat water so it takes a bit."
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9oqlrs | Why do a lot of spacecraft use gold foil? | Technology | explainlikeimfive | {
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"Because it is almost optimal for everything from heat transfer to electrical conductivity, corrosion resistance and shielding from radiation. Just about any of those uses it is amazing at.",
"Actually, they aren’t: URL_0 At least not always. Gold is used in some cases, as a thin coating allows in visible light while blocking harmful wavelengths of light. It’s also a highly conductive and corrosion-resistant material for use in electronics. This is useful both in space and on the ground.",
"But understand this. A piece of gold the size of a dice can be flattened and stretched to the size of a football field. At that thinness it is see through but can still be very functional for many purposes."
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9ose3d | Discord is ad free and only has a 5$ optional subscription fee. How do they afford to service their close to 100 million users? | Technology | explainlikeimfive | {
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"Investors. Right now Discord is not bringing in a profit and they are losing money. Investors in the company are giving them money to continue to operate until they can figure out a path to profitability. This is a very common business tactic especially in tech/software businesses.",
"You're vastly underestimating the number of people willing to shell out $5 for some flashy emotes, and you're vastly overestimating the marginal cost of scaling a service like Discord once you've got the initial infrastructure in place. Plus you can't forget the rule of all \"free\" services online: if it doesn't cost money, you're the product.",
"They just released a subscription based game library. For $9.99/month you now get access to a bunch of games, on top of getting their \"Nitro\" membership benefits. Only time will tell if it's successful though. Until now I think they survived because of investors and their Nitro membership subscription. I'm sure that they are also using your data for some extra profit, but I haven't verified that.",
"It will eventually be monetized, or once it gains a very sizable following, will be sold so that all initial investors make their money back along with some profit. The company that purchased it will have a way to monetize it. Twitter only made a profit this past year. It’s been around since 2006, and has A LOT more users than Discord. Ads have ramped up a lot the past few years. YouTube was also a free service, and had zero ads. After they got a huge user base, it was sold to Google, who then monetized it with ad revenue. Expect that Discord will eventually start limiting the number of users per server unless you buy a Premium Server, and the number of people allowed in a chat room will be limited to like 4 unless you pay an upgrade cost. It’ll happen.",
"In addition to the other things mentioned here, it's worth pointing out that they've been *constantly* seeking new employees for years now (although only a few at a time), which tells us from a software dev standpoint that they certainly aren't running a fully-saturated crew (probably multi-skilled techs filling in & wearing multiple hats, so to speak). Combining that with the typical working habits expected of startup companies like this, and it's not unlikely that the team itself has probably been stretched pretty thin on their massive work loads as a means to keep employment costs down, and have been making position openings where they *absolutely need* the relief."
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9osm8p | Why do pixels on certain digital devices like old calculators cast a shadow? | I've just noticed how the black pixels on monochromatic, non-backlit screens like digital radios and calculators cast a shadow on the screen itself, how is that happening? | Technology | explainlikeimfive | {
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"i believe the device you're referring to is a LCD liquid crystal display. basically its a clear liquid that turns solid and opaque with the applicaation of a minor electric current. so that opaque segement is actually blocking light, casting a shadow on the reflector behind it."
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9otphs | Why does CGI cost so much money? | Technology | explainlikeimfive | {
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"text": [
"because it takes forever and a lot of training to use the animation programs. it takes animator hours to create a short sequence sequence, then it can take hours to render that sequence."
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9ou3ub | Why does in private browsing let you view more articles on a website that restricts you to a certain amount of free articles per month when you've gone past the limit of free articles? | Technology | explainlikeimfive | {
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"Before I answer this, let’s first answer the question how websites know you’ve read a certain amount of articles in the first place. They do this through a method called caching. In simple terms, it is somewhat of a temporary storage in your computer so when you visit the website again, you don’t have to request everything again. This improves page speed since you only need to ask what is new and up to date. Now, when you browse privately, the browser doesn’t store the cache. I mean, they do but once you close the browser, it’s gone. Also, when you browse privately, the cache from your non-private browsing isn’t carried. It’s assumed you’re starting from scratch. That’s the reason why you have to sign in to every website in incognito even though you already signed in. EDIT: As /u/krystar78 pointed out, apparently it isn’t cache but cookies."
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9owfhq | How do our eyes have such big dynamic range and why cant we replicate camera's with the same range? | Technology | explainlikeimfive | {
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"Our eyes are not just looking at the scene, it is assessing what to focus on at any given nanosecond. So a picture attempts to force a perspective that \"hey, look at the beauty of this evening sky, or the awesomeness of the football game\" but it can't capture that. That's why other people posting pics of the Harvest Moon are so boring, or \"the Beach.\" We don't just see with our eyes, we assess and analyze. That's why a person can be considered cortically blind; their eyes work, but their brain is damaged that where they would process the information so functionally they are blind. Pictures are a representation of our world.",
"Eyes don’t actually have as big a dynamic range as you’re imagining – instead we constantly scan around a scene and our brain basically does live HDR to make it seem as if you can see simultaneously into deep shadows as bright highlights. FWIW the iPhone XS does a similar thing with its Smart HDR.",
"Our eyes have a single, flexible lense which is controlled my muscles to change the vocal point, I think it would be ridiculously difficult replicating the same with a camera. The lens in your eyes is stretched or squished by muscles to change the vocal point, its just much easier making cameras with fixed lenses that you can slightly adjust the focus"
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9oygb9 | How do the bakery's cut hot dog buns when they are still all stuck together to the other hot dog buns in the package? | Technology | explainlikeimfive | {
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"text": [
"Hot dog buns are usually 4 across. THey are cut with three knives, so you end up with this pattern of bun sides cut uncut, uncut cut, cut uncut, uncut cut The side buns are cut normally the middle gets cut with a pointy flat spike that goes all the way through and cuts two buns, thats where you get the two cuts against each other."
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9p00p7 | connecting 2 computers with usb | Technology | explainlikeimfive | {
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"text": [
"USB is based on a host/client relation. The computer or host side (A side of the cable) contains the more complex hardware needed to manage one or more USB devices and coordinate the sending of data so that messages don't overlap and interfere with each other (remember that with hubs you could have 127 devices connected to just one USB port). The client devices (B side) normally contain much simplier control chips designed to take commands from the master. Part of this relationship is that USB client devices have to wait until the host tells them its ok to send a data packet. There is a way for them to effectively raise their hand so the host knows they have something to say but they still can't speak unless spoken to. So if you just made a cable with two male A connectors it wouldn't work because both sides would try to be in control and will disagree over when data can be sent. There are USB transfer cables though. They work by really being two cables with a small device in the middle. The device acts as a client to both USB hosts and handles passes data to either side of the cable - in this way both computers are talking to a client device.",
"It is. When you plug a flash drive, external hard drive, or even a phone into a computer via USB you can transfer data.",
"It is possible but you need a specialized cable that has a processor built into it. & #x200B; USB is designed to work between a host and a device. The computer is the host and the other piece of equipment is the device. The host has one kind of US chip inside it and the device has another. In order to make sure that no host was connected to a host or device to a device, the shape of the connectors for each end of the cable were made to be different. & #x200B; With the new version of USB connector, known as USB-C, the connector is the same on both ends. Also there are specialized cables that have USB-A (host connector) on both ends. Those cables have a chip inside that acts as the \"device\" and talks to two different \"hosts\" (each computer) at the same time passing information between them."
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9p3yo8 | Why do electronic devices, after having a technical difficulty, usually fix themselves after you turn them off and then on again? | Technology | explainlikeimfive | {
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"Computers rarely make mistakes. Humans make them all the time. Sometimes humans make mistakes when writing a program for a computer and the computer has no way of clearing that mistake. Depending on the device this can cause some real issues. A reboot is a fresh start free from the mistake. It's kind of like whisper down the lane. Once the message is fucked up and doesn't make sense it's easiest to start over instead of continuing to spread non sense.",
"When you turn on a device it has a setup process. Most errors occur after the setup state therefore by restarting you return it to the good setup state.",
"On computers and other similar electronic devices, crashes occur from software bugs (resulting in infinite loops or errors). Restarting will stop everything, and start it back, which usually can resolve a problem from crashing. Or if the computer runs out of RAM, restarting will put all necessary data onto the hard drive and then clear all data from the RAM, and restart everything and putting necessary data back onto RAM when needed.",
"One way to define computers is as state machines, that may sound complicated, but it really means that computers can really be defined as a whole bunch of rules, when X, do Y, when Y, do Z, when Z, do B. Many computer bugs are really just conditions that the computer programmer never thought of (like somehow, they set it to K, but never made a rule for K, so the computer just does nothing forever because it doesn't have a rule). Rebooting generally involves setting the computer to it's startup state (that is, when you push the power button it starts with \"set to A\"). The important thing here is the developer absolutely tested turning it on, so the startup state is one of the least likely places to have a problem. Additionally, while the program might not have a way to get out of the K state, rebooting is a way to do just that.",
"Code is essentially a tree-like structure, with each bit of code branching off the current part in a different direction. Occasionally software bugs occur where some set-up or tear-down has either been missed or is not present, causing resources to remain in their current illegitimate state. By restarting you are beginning at the entry point of the program, and would have to work your way back up the tree to get to the same error section again, which may or may not be possible depending on the conditions required to achieve the error in the first place."
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9p6rjw | Why aren't state sponsored cyber attacks considered an act of war? | Technology | explainlikeimfive | {
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"Basically, everyone's doing it. & #x200B; If one nation suddenly decided it's tanks on the lawn time, then everyone else would have the same excuse - You can't claim the moral high ground when proof is released that you were doing the exact same thing to your enemy.",
"A cyber attack is an extremely broad term. It could be as simple as accessing a single network node and shutting it off, or remotely getting into the central data center and stealing Gigabytes of data. The latter is much more easy to detect while it's happening, whereas the former it typically a \"get in, hit the target, get out\", so it's unlikely to catch those in-the-act (they're also far less common). Because of the nature of the Internet, even if all signs point to a certain nation-state carrying out the attack, it might not necessarily be an attack authorized, coordinated, or carried out by that nation. Many people online use a VPN/proxy service, which basically works like \"Sure, I'm physically in Paris, but I want the Internet to think I'm in Ontario\", or \"I'm in Russia, but I want anyone who might be tracing my activity back to think I'm in Chicago\". Use of a VPN/proxy isn't, by itself, illegal. Because of that, there's still too much uncertainty with regards to most cyber attacks to be 100% certain that \"yes, this attack did in fact originate from someone working for this country's government.\" It is, however, possible to get a good idea of who carried out some cyber attacks, based on a form of digital signature, the manner in which something is done. However, it's also possible that some countries' methods have made it onto the \"Dark Web\", and rogue hackers can follow those methods to try to hide themselves by making the victim think it was someone else. Sorry... this got really long... TL;DR: it's very hard to catch someone \"in-the-act\", hostile actions can have their locations masked via VPN/proxy, and rogue individual actors can hide behind known methods carried out by countries.",
"For the same reasons that most acts of espionage are not acts of war. One, everyone is doing it. Two, because military response has to be proportional for rational actors (ie gunning someone and their whole family down because they cut you off in traffic isn't appropriate). Three, because the occasions you want to get into war are far far fewer than the opportunities to get into wars. Countries only start wars they think they can win plus benfit from, or because their hand is forced by a legitimate attack/invasion that presents existential threat, or close to one.",
"they will be, when people start dying as a result of them. the reality is that we’ve not experienced a sustained attack on any critical systems yet that have endangered or cost lives.",
"This is actually an ever-evolving discussion in politics and defense. The first problem is determining where to draw the line. What digital attack justifies physical use of force? Would you send missiles in response to a digital bank heist? Do you wait for your adversaries to take down the entire power grid before sending the bombers? The mostly-agreeable consensus is when the attack results in physical consequences (eg. cyber-attack blew up a power plant resulting in xx injuries/deaths). The next problem is what is a reasonable physical response to such an attack? How many people do you kill in response? How much infrastructure do you destroy? And that can only happen if you're dead sure you know whodunit. Some attacks are pretty easy to tell where they came from, others are impossible to determine. If you're committing soldiers and killing people, you want to be 200% sure that you're toasting the right bagel. Compounding this problem is the fact that cyber-attacks are not always committed by the nations themselves. It could be an advanced cyber-crime group or other actor. The potential for false-flag attacks in this scenario is also huge. War is the very last thing on earth a nation wants to do (at least it should be). You have to weigh the pros and cons of the situation and determine if the benefit in going to war (destroying your enemy) outweighs the costs (lives lost, economy lost, pure financial cost), and that's if you're sure you can win. Georgia is slowly being invaded by Russia, but it's not like they can realistically do anything about it. Ukraine lost a good chunk of land, but it's not like they could have defended themselves. The UK had *nerve agent* used on its soil and kill its citizens, but they have no hope of winning against Russia on their own, so they just move on. --- The bottom line is that it boils down to two questions: - Are you absolutely sure you know whodunit? - Do you really want to go to war over *this*?"
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9pbd5x | How do machines record sound? | I’m not sure how this happens, and it would be very nice to know. Only thing I thought it could be is remembering the movement of the sound waves hitting it... but it’s a shot in the dark and I can’t find it online. | Technology | explainlikeimfive | {
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"The short, simple answer is that you use something that vibrates easily when sound hits it and attach a sensor to that. Like old ribbon microphones, the ribbon vibrates with sound waves passing over it, and you attach a bit of circuitry to it that can measure how the ribbon moves.",
"When you move a magnet through a coil of wires, it induces an electrical current in those wires. Microphones work on that principle - they use a diaphragm to catch the sound pressure waves and transfer them into the movement of a tiny magnet in a coil. The electrical signal produced by this is a very close electrical representation of the sound. Back in the \"analog\" days, this signal would be amplified or attenuated to be directly recorded to a medium like magnetic tape. These days, a lot of recording is done digitally, meaning that instead of the electrical signal being passed along and copied as a continuous wave, it's broken down into millions of discrete measurements per minute that can then be reconstructed into a wave. Reproducing sound is the exact opposite process of recording it: the digital samples are reconstructed into an electrical wave signal, which is amplified and used to move a magnet in the \"cone\" of a speaker to produce sound."
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9pcl9n | How do photographs actually work? | Like how can we “print light rays” like this is so confusing and most sites confuse me even more Sorry for some weird grammar, English isn’t my native language | Technology | explainlikeimfive | {
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"text": [
"Certain silver containing chemicals react to light by turning from clear to black (transitions lenses use the same reaction to darken in light). These chemicals are the basis of film photography. Black and white was earliest and more simplified so let's start with that. We take advantage of this reaction by putting them in a dark box and then exposing them to a little bit of light in the form of an image that turns them black (you can see the image with a [camera obscura]( URL_0 )), and then permanently stopping the ability for the rest to react. This makes a negative (the more light shined on a part of the film the more black in the image). To make the negative back into a picture we shine light through the negative (now the black blocks more light and the light lets it through) onto a sheet of paper coated with the same silver chemicals that turn black with light exposure. This restores a positive image. To make a color image, we use three pieces of black and white film each capturing a primary color, the[ earliest methods]( URL_1 ) used three separate layers, but later film stacked them with color filters in between and pigments that attach to the silver color changing chemicals. Digital photography is just millions of what are essentially very tiny solar panels each with a color filter over them (so they can only capture red or green or blue light). Based on the electricity they each generate, the camera's sensor knows how much light each received, and combines them to make pixels in a digital image.",
"Original photography works using silver nitrate. You know how if you heat up orange juice that you put on paper in the oven, the juice burns and you can get a picture? Silver nitrate does the same thing, except it works with light instead of heat. Paint a bunch of the chemical onto paper in a dark space, and expose it to light. It will burn in the pattern the light has on it based on the intensity of the light, forming an image. You need to do this fast and limit the amount of light, otherwise it all burns and turns black. You can do that by installing a shutter (a fast open and close device) and an aperture (a tiny hole to make it so you can only get a little light.) Electronic photography works on the same concept, except we now have electronic parts to detect light instead of chemicals. Do this 24 times a second or so, and you have video."
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9peai2 | Botnets, what are they? | Technology | explainlikeimfive | {
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"text": [
"Essentially, a botnet is a group of \"enslaved\" computers (for lack of a better word.) A malicious hacker would have created a trojan virus that has the ability to control the computer it has infested- giving the creator a chance to either further spread the trojan or begin attacking with a large number of computers."
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9pgbwg | How do they reenact concerts through projections? | Technology | explainlikeimfive | {
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"text": [
"Never mind, really high. Just realized the video is from 1995"
],
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37
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9piggq | How is deleting old emails good for the environment? | Edit: URL_0 | Technology | explainlikeimfive | {
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"text": [
"I'm not sure that it is, particularly. In theory, deleting old emails frees up space on the server or the PC, so maybe the computers won't need to be upgraded so often if everyone keeps deleting old messages. But I'd imagine that the effect is minimal.",
"Email is a drop in the bucket compared to video (YouTube, etc). And what about all those photos backed up in the cloud? Don't worry if you use Gmail (or similar). They run super efficient data centers. Your equipment used to delete the email is using electricity, too, btw. If you work at a company that runs their own Microsoft Exchange servers and needs to buy hard drives on a regular basis and expand their data center then it may add up. I used to work at a company that forced employees to clean up their email regularly to save expenses in IT. The software engineer time wasted clearing the inbox was worth significantly more than the savings in hard drives. The storage policy was then changed :-) Deleting email is generally a waste of time and money. (There are other reasons to delete them, e.g. retention policies, but that is a different story)."
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9pikvc | How do laser printers work? | Technology | explainlikeimfive | {
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"text": [
"Laser printer toner is given a small negative electric charge inside the cartridge. Another component, the *charge roller,* applies a uniform negative electric charge to a photosensitive drum roller. Thus, the drum will repel toner, preventing it from adhering. This is where the laser comes in; by sweeping across the drum and pulsing on and off in sequence, the laser \"writes\" the image of the document being printed onto the drum roller, neutralizing the charge and letting the toner stick. Afterwards, the drum presses the toner against the paper as it passes through; since the toner exhibits a greater attraction to the paper than to the drum, it sticks to the paper instead. Some printers have a positively-charged transfer roller to help with the process. Heat and pressure fuse the toner to the paper, resulting in the completed printout."
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9pjd4n | What measures a write cycle on an SSD? | I know what it is in theory, but what I don’t know is how it’s measured. Is it a certain amount of gigabytes saved? A certain amount of time spent writing data onto the drive? I hope I’ve explained the question sufficiently to be answered. | Technology | explainlikeimfive | {
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"Flash consists of billions of transistors that store data by pushing electrons through to a floating gate. They're pushing them through an insulator which gets damaged each time and will break down eventually. The \"write cycles\" spec is how many times you can write to each transistor before they break down and can't accurately store what you want If you had transistors that worked fine at 999 write cycles and we're dead at 1000 then the max life of a 256 GB drive would be 256 TB written In practice though, 1000 write cycles is the mean time between failures (MBTF) meaning they have a 50% chance of failing after that many cycles, and the manufacturer will spec that lower than reality(may actually be 1200). We also put extra flash on SSDs so we can rotate in new blocks when some get over used so your 256 GB drive may actually have 300 GB of flash on board(called over provisioning) to extend it's life [In practice you can write 900-1200 TB to a 256 GB drive over it's life]( URL_0 )"
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9pk6f2 | how glass and paper products are somehow better for the environment than plastic? | Is it simply just because they are biodegradable? I’m not doubting that plastic is horrible for the environment, but I’m kind of confused as to how paper or glass products is a better alternative when we have to cut down trees for paper and glass is heavier than plastic, meaning (possibly) higher transporting/fuel costs? | Technology | explainlikeimfive | {
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"text": [
"Glass can be easily recycled and so can paper. Paper also biodegrades readily, both are better long term than plastic/fossil fuel products including transport and production emissions. Plastic is just cheaper.",
"Glass is one of the few materials that is 100 percent recoverable/ recyclable. Paper is also recyclable and biodegradable. Cutting down trees if done correctly is not bad for the environment. Thats is why there are different types of logging. Different methods are used in different areas to keep it sustainable.",
"In the shortest terms possible: Plastic comes in a lot of different types, colors, etc. When heated incorrectly, it stops being plastic. When there are contaminants, it doesn't make new plastic very well. This is why most is thrown out. Glass is glass. It does come in several types and colors, but you can melt it down and make new glass pretty simply. Melted glass is still glass. Dirty glass still can make nice clean new glass. Same concept with metals. Someone else might be able to help regarding paper."
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9pkzy6 | Difference between AED and manual defibrillator (I think that’s what it’s called.)? Do both reset incorrect heart rhythms or can either restart a flatline? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Both an AED and a hospital defibrillator cannot start a stopped heart. They shock the heart which causes it to stop beating and then it restarts naturally into a hopefully normal sinus rhythm. An AED detects the electrical activity of the heart and then determines if a shock is necessary to get it back into rhythm. In a hospital setting you have a medical team that is evaluating your heart rhythm and determining whether or not a shock is necessary. This is not the most detailed answer but it should give you a basic background."
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9pl2lg | How exactly does cruise control work? | Technology | explainlikeimfive | {
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"text": [
"There's multiple ways for cruise control to work. The first way is outdated and only used on old cars that have a throttle cable. When you engage it, it turns on a motor that will hold the throttle valve in the desired position. As you go up/down hills, the motor will open/shut the valve to compensate for speed. The modern way to do it is controlled by the car computer. It's basically the same but you can now control fuel injector duty cycle etc to make it more efficient. Modern cars also have electronic throttle control, so there are no cables"
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9pmh6t | Why are graphing calculators still huge and clunky when our smartphones can harness the internet to perform the same functionalities in 1/5 the physical size? | Technology | explainlikeimfive | {
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"Smart phones are also 5x as expensive, so that is the trade off here. Comparatively, a graphing calculator is a simplistic device using simplistic hardware and software to perform a narrow range of functions.",
"Because they haven't changed their fundamental designs in about 25 years. They have contracts with the schools and textbook publishers to use their calculators, so they have no financial motivation to improve their tech at all."
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9pnyxz | What do bits and bytes look like and how are they moved around from computer to computer? | Technology | explainlikeimfive | {
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"A bit is *physically* stored in a computer in a number of ways. On a hard disk, you have a platter, which is a nickel disk that spins at 7.5k RPM, and an electromagnet can change the pole of a surface region - so a bit is going to be a north or south pole. In an optical disk, like a CD, DVD, or Blueray, it's going to be etches in a magnetic foil in a spiral pattern, there will be several spirals called tracks. The etch can be long or short, like Morse code. It's not the etch that signifies the bit - it's the reflective surface in between. The laser shines on the foil and reflects onto a sensor; the etch deflects the laser into dead-space. Long and short spaces between the etches signify a 0 or 1. On solid state media, like a thumb drive or SSD, you've got these transistor constructions that are able to hold onto electrons, even with the power off, for *years*. One per bit. This isn't like a capacitor or battery, it works under a different property that's a bit beyond me. Your system memory, RAM, is banks of capacitors, one per bit, their charge or discharge is a 0 or 1. These capacitors have a limited charge, and discharge themselves quickly, so there is a refresh rate where they are checked for their state, and given an additional jolt if they're supposed to be charged. When you read a bit, the capacitor actually has to discharge, and then to keep the value, a feedback loop will cause refresh to charge it again. If you want to set a bit to 0, you have to discharge that capacitor into a sink. Your CPU cache is done by a flip-flop, which is a type of circuit made of transistors. These are loops that either carry current, or don't, and that gets you your bit. They're very fast, which is why they're used on chip, but they're also very big, which is why they're not used in RAM. A bus is just a bunch of wires, whether over a cable or traces etched on a circuit board. Typically, RAM to CPU will have one trace per bit, so when you read a \"word\", you're reading multiple bits in parallel. A word is going to be the minimum read and write size of your CPU, so if you're only interested in 1 byte, the machine may necessarily read and write 4, 8, 16, 32, 64 bytes at once. Or more. A bus may also be multiplexed. So if you're reading 8 bits, it may go over 1 wire, and those bits are sent as a sequence of electrical pulses in a well defined order. Other busses and channels may rely on more elaborate signaling. USB uses a differential signal - 2 wires carrying sine waves that encode multiple bytes at once (which gets a bit out of scope of what I'm talking about), but the sine waves are opposites. The bits are extracted from the difference between the two signals - how far the peaks and troughs are from one another. This is to account for noise - you see, any conductor is an antenna. That's why crystal radios pick up AM broadcast when you use the kitchen sink as your antenna. So if you have a long-ass ethernet or telephone cable or whatever, it's going to pick up electromagnetic noise from everywhere, which can corrupt the message. It used to be that a signal was encoded some voltage relative to ground - but ground at the source could be a different energy potential than ground at the destination, so you send 5v and they receive 4.3v. With two wires and differentiating the signal, the value is always relative. If you pick up noise, both signals will be affected the same way, the difference remains the same. So to address the end of your question, whether it's a signal over Ethernet, coax, a bus, or Wifi, it's going to be a sine wave, because it's all electromagnetism. And this is the subject of modulation, of which there are many types - you'd be most familiar with AM and FM, but there's more than that.",
"There are a few ways to actually transmit 1s and 0s. One is simply to have two different voltages representing them. One might be +5V and zero as 0V. That needs a physical wire and a common voltage reference so only really works within a computer or directly connected peripherals like a printer. Another defines two frequencies as the alternatives. Send a pulse of high frequency for a 1 and a lower frequency pulse for 0. Back in the days of phone modems, you could listen to the squawk of the audio frequencies sent over the phone lines."
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9pszzi | why can't you connect multiple wireless headphones to the same phone via bluetooth | Technology | explainlikeimfive | {
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"Because Bluetooth audio creates a 2 way connection to encrypt the information so that others can't listen in. To have two people listening at the same time, you would need to be able to create 2 separate Bluetooth audio signals each encrypted for the listener. This might be possible, but no one has implemented it because there isn't enough demand. Or it might actually require multiple Bluetooth antennas to transmit the multiple signals.",
"You can. The OP question does not specify that each device accesses the same stream. In that case other answers are more correct.",
"The type of connection you're using must allow for multiple instances of that connection on a piconet. This is easiest to explain by example. You can only have a single Bluetooth audio connection for music streaming. The reason for this is that the A2DP profile for audio streaming is designed to have only a single connection active at a time. So you cannot connect your smartphone to two Bluetooth speakers at the same time."
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9pwhf2 | Why is Wi-Fi slower than ethernet? | Technology | explainlikeimfive | {
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"Its the difference between drinking out of a bottle and out of a water fountain. Any non physical connection makes transfer harder to get the same amount of stuff.",
"You're trying to fill up a cup with water. If you fill up the cup with a hose, you fill up that cup faster, but only a cup at a time. If you try to fill up that cup using a sprinkler it fills up slower but you can fill up multiple cups at once. Does that make sense? Lol.",
"Simply explained, it’s just not a physical connection, which is direct and connected straight into the modem",
"WiFi is a shared medium. Everyone is talking on the same channel, and as a result ends up talking over each other. While there are multiple channels, many of them [overlap with each other.]( URL_0 ). And that's just for actual WiFi communication. Anything else that doesn't fit nicely in the WiFi scheme but transmits over the same frequencies like microwave ovens also causes interference. So it ends up working like trying to have a conversation in a bar. When it's quiet, it works well. But the more people arrive, the more people talk over each other, which raises the noise level, until bandwidth becomes almost nonexistent and conversations get reduced to \"ANOTHER!?\" \"YES!!!\" Ethernet in comparison is not a shared medium in its modern version. Wiring means that nothing external intrudes, and switches have the capacity to connect any source to any destination without internal bottlenecks. Any good switch advertises the ability to have every port both transmit and receive at the maximum speed, at once. Meaning that a 32 port 1000 Mbps switch allows each of the 32 ports to both be sending and receiving at 1000 Mbps at the same time.",
"Not the whole answer but largely it's packet overhead. Wifi isn't like a laser connector beaming information between the receiver and the router, it's more of big expanding bubble talking that talks to everything it hits so there needs to be more encryption and protocols to make sure it's talking to the right device. In certain cases there's also the difference in the amount of data that a wifi receiver can handle opposed to a physical connection leading to lower maximum bandwidth."
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9pwo4g | Red Dead Redemption 2 releases in less than a week. The full 90+ GB game is installed on my hard drive. How are developers able to keep this content locked without someone finding a way to crack it open early? | Technology | explainlikeimfive | {
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"Encryption is a wonderful thing. In the most basic terms there are mathematical operations which are easy to do in one direction but practically impossible to reverse. This allows messages, or in this case huge amounts of data, to be encoded in a form that cannot be made sense of without a key."
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9pxlcm | Why has non LTE service slowed down over the years? | Technology | explainlikeimfive | {
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"Re-allocation of frequencies. Each provider has a certain amount of spectrum at any given location, and it gets split up to be used by various technologies. LTE is both faster in general and more efficient, so as we reach a point where most people have LTE-capable phones, they take spectrum that was allocated to 3G/4G and move it over to add more capacity to LTE."
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9q1jme | why is copper used for heat sinks, and why are there no phone cases made out of copper that keep the phone cool? | Technology | explainlikeimfive | {
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"Because it conducts heat very well and would have the reverse effect in a hot car etc. so it would be counter intuitive",
"The main factor is copper is simply more expensive than aluminum, and copper serves no purpose better than aluminium(copper oxidizes easily, has the same heat conductivity, and maybe structurally weaker than some alloys of aluminium)",
"Heat sink work because fans carry the heat away, which is only effective with a fin design (lots of thin copper plates) for the air to blow through. A solid copper case would only hold onto heat and overheat the system."
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9q1njd | What does Temple OS do extremely efficiently compared to other operating systems like Windows, DOS and Linux? | Technology | explainlikeimfive | {
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"The main technical novelty of TempleOS was how tightly integrated Terry's \"HolyC\" language was in every part of it. The terminal was just a HolyC REPL, for instance. Basically, you did everything by writing HolyC, which was then interpreted. HolyC itself was pretty cool. HolyC source code have bitmap images, colors, and more. Of course, the main \"novelty\" was just how insane it was for one person with such a mental disease to build something as complicated as an OS.",
"It doesn't. Your information about how it is so amazingly efficient is likely skewed by someone with an agenda. Perhaps it is the mentally ill author of TempleOS; no slight against his programming skills, his beliefs about the origins of his operating system as being ordained by God are due to his schizophrenia and not representative of some inherent superiority of the program itself.",
"A lot of inefficiencies in modern operating systems are due to backwards compatibility and feature creep. By starting from scratch and justifying every bit of lo-fi UI as a covenant with your god, you can streamline your system a lot."
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9q2eks | What are the differences between guitar pickups for electric guitars and acoustic guitars, including those which mean acoustic pickups need a battery as well as the amplifier? | Technology | explainlikeimfive | {
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"There's 2 types of pickups that I know of. The first one is the most common and uses an electromagnetic field to transpose string vibration to an electric signal that can be amplified. When the strings vibrates, it changes the electromagnetic field around the pickup. These changes depends on the size of the string and how fast the string vibrates, and are picked up by, well, the pickup. The resulting low voltage electric signal is then sent to the amplifier which makes it louder (and optionally add effects to it) and then out its speaker. These pickups are available for both acoustic and electric guitars, and come in passive or active models (active work with a battery and give more gain and control over the sound). It produces a clean, \"dry\" tone. For acoustic guitars, it is either installed directly under the saddle in the sound box or over the opening of it. They usually come with a small control box and are active. The second type is basically a small piezo microphone installed in the sound box. They produce a richer tone, and usually come with an equalizer in a control box embedded on the side of the guitar. Piezo mics work similarly to standard microphones but they exploit the ability of some minerals to produce electricity when subjected to pressure. They usually have a tiny quartz crystal that will be compressed on each microphone diaphragm vibration. The voltage output from the crystal depends on the pressure it was subjected to and how fast the string vibrates. This signal is then sent to the control box for sound control and pre-amplification, then to the amplifier. Hope that helps!"
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9q2wrd | If mobile processors are now (in some cases) overtaking laptop and desktop processors in terms of power why aren't they universally adopted into all laptops and you could make the battery last 10 times longer? | Technology | explainlikeimfive | {
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"Your premise is wrong, mobile processors don't outperform desktop processors. Not by a long shot.",
"Are they, though? Short answer: No. Mobile processors are a long, long way behind laptop and desktop CPUs. Long answer: Laptop and desktop processors do **a whole lot more things** than mobile processors do. The mobile CPU is very dedicated and streamlined in order to offer a great experience with the limited applications it is expected to perform. Laptop and desktop CPUs are extremely powerful and versatile components that handle so much more, so much more often, and so much better that there isn't even a meaningful way of comparing the two. Take standard benchmarking operations like LuxMark for example, and even the absolute top of the line smart phone processors score single digits, whereas even budget CPUs score in the triple digits. Laptop and desktop CPUs are better by orders of magnitude. But that isn't to say that mobile CPUs are bad, either. It's just that they're specialized to do a different set of tasks. The question, then, becomes \"how do we compare them?\" To which the answer is, \"we don't. It's like comparing a CPU to a GPU and wondering why the numbers don't add up.\"",
"Mobile processors use ARM architecture, which is a lot more efficient than the x86 architecture used in laptops and desktop computers, because it has less instructions and other stuff. So why doesn’t everybody use ARM, well, the problem is that we use x86 pretty much just for backwards compatibility, all normal windows programs just don’t work on ARM, and Microsoft tried to fix this, by releasing windows 8 for ARM and and App Store with cross compatible apps, so you could used them both on older PCs and new ARM laptops, but that failed big time, since none of the big software companies supported that"
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9q5c3f | Why do some songs sound much louder/crisper than others on some music streaming services? | Technology | explainlikeimfive | {
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"Before streaming services, music was mostly heard on the radio and on media like vinyl records, cassette tapes, and compact discs. Part of the process of producing music is a phase called \"mastering\" where the recorded songs are tweaked to sound the best on whatever format they are being sold in. So a version of a song could be mastered *differently* for a record, cassette, and CD. & #x200B; Now that we have digital music streaming, songs are being mastered for those services as well, but the different is that each service also tweaks the audio after it's been given to them. Each service does this differently. & #x200B; So there are lots of things at play here, some songs might be mastered by the record label differently for different streaming services, *and* each service does their own tweaks before it get to the users."
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9q6pph | Intel's current naming scheme for their processors | Technology | explainlikeimfive | {
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"Simply put they are indications of the tier in which Intel has positioned the processors. The higher the number the better the processor in general, so an i3 might have two processors while an i5 has four, or maybe an i3 and an i5 both have two processors while the i5 has Turbo Boost to dynamically increase clock speed when needed and maybe a larger cache. The specifics of how exactly the tiers differ depends on the generation of processor so *why* exactly the higher tiers are better varies."
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9q70tg | How does the Shodan search engine work and how would one use it? | I do know the "internet of things" catchphrase and I understand it searches for devices connected to the internet. What I don't understand is how that works. I need an ELI5 for explanations like "it (Shodan) does query ports 80 and 443." | Technology | explainlikeimfive | {
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"The world now has a vast array of gadgets that are connected to the internet. To allow users to connect to the device, the device has to listen for incoming traffic. Ports like 80 and 443 are just designated entry points for internet traffic to flow with some restrictions to prevent bad people from gaining access to the device. Of course, most people don’t bother securing their systems or updating their password, so their devices are still insecure. Shodan just sniffs around for these access points and, when it sends a request to the device and gets back a response, it can use the response to determine what it has found. If it’s a router, it might return a message containing “Linksys router login”, for example. This information is catalogued and analyzed so it can be sold to interested companies."
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9q989w | We have free Wifi on Trains, Ships, Buses, Metros etc. What makes it so difficult to have free Wifi on airplanes? | Technology | explainlikeimfive | {
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"Demand plays a huge role: there is virtually no competition for data services in flight, so a airline can charge what they want. Most airline passengers who want/need the service could be willing to pay for it.",
"Saw a YouTube video explaining this a while ago. Basically planes are designed to be as light as possible and space is used as efficiently as possible. That means there isn't really spare space. Internet on planes are satellite based and as a result, require large antennas mounted to the top of the plane. With space so limited, often these antennas bulge out of the fuselage. Not only is this expensive to implement, but the aerodynamics of the plane become less efficient. That means you're burning more fuel for the same flight. That directly contributes to wifi prices being so high on planes.",
"One reason is that the ways to get an internet connection to an airplane are more expensive than most other types of internet connections. Most in-flight internet providers use either a proprietary ground-based system (similar to a cell phone network, but with antennas aimed up instead of at the ground), or a satellite system. Both types of networks are really expensive to maintain and operate, and the ground-based systems have to be built just for airplanes. Another reason is that the connection is usually pretty slow, so pricing can be used as a way to limit the number of people sharing that connection.",
"On a bus or train, the wifi is backed by a cell tower. If you're underground in a metro, sometimes you can see little microwave cell antennas in the ceiling, being the cell. This little cell on the ceiling is in turn backed by a fiber line or something. Ships are too far away from any cell towers. and airplanes are out of range vertically, though you can sometimes see towers on takeoff or landing, after they let you turn it back on but before they've climbed too high. These need to use communication satellites, which are much more expensive than cells, and you usually pay by the MB. My guess would be that flights are usually a necessity, so neither customer nor airline wants to pay for anything they don't have to. Cruise ships, on the other hand, are luxuries, so they do things like 'free wifi' to make it seem more luxurious, then jack up the price of the ticket.",
"We might have wifi on all those modes of transport, but it is rarely free to the majority of the world. The cruise I just came back from was AU$2/MB for cell-based wifi, or AU$134 for the ship's wifi for the 8-days."
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9qaxu6 | Why do 1080p movies looks sharper than 1080p video games? | Technology | explainlikeimfive | {
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"Because the source material for a game is created from scratch then rendered by the game system. A movie is typically recorded in 4K or 8K then played back the lower resolution 1080p.",
"A movie is like here show these paintings A game is like here are some colours and a Description now paint it and fast. So you could have a game look like a movie if speed wasnt important"
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9qdx26 | Why do credit cards only start with 3, 4, 5 or 6? | Technology | explainlikeimfive | {
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"This is just a guess but I think the first few numbers denote what credit card company it is (visa, MasterCard, Amex, etc).",
"The first 6 numbers of a payment card are called the [Issuer Identification Number or IIN]( URL_0 ). Each institution that issues cards have their own numbers. Visa cards always start with 4, Mastercard with 51 to 55, etc. There are cards that start with other numbers than 3, 4, 5 or 6 but they're not very common where you are.",
"[They don't!]( URL_1 ) All *consumer* credit cards start with 3-6, which means that for the vast majority of people, those are the only numbers you'll ever see (or need). The other numbers are either industry specific or have not yet been assigned: for instance, 1 and 2 are for airlines, 7 is for the petroleum industry, and 8 is for healthcare and telecom. The first digit identifies the \"major industry\" the card will be used for, as well as the issuing company in the case of consumer cards. For instance, all Visa cards start with 4, and all Mastercards start with 5. If you've ever filled in credit card info on a website and seen the page then \"guess\" what type of card it is (for instance, by highlighting the correct icon and graying out the others), that's how it knew. The middle 13 or 14 digits vary depending on the issuing company, but will usually identify your bank and your account number. The final digit is a \"[check digit]( URL_0 )\", which is used to catch errors on identification numbers when credit card numbers have been added manually."
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9qg4ve | How is a game optimized? | Technology | explainlikeimfive | {
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"This happens with ANY software not just games. Developers write code sometimes that is ***easy*** to do, but doesn't *perform* very well. Often we do this because 1) we are not always sure of the best approach to take with a software task AND/OR 2) we need it working quickly, because other parts of our software depend on it. Even in the case of #1, it is just ignorance or lack of knowing what the software will do when under full load. Once it hits a later development cycle or QA (i.e. the testers) they may start seeing the performance problems. \"Optimizing the game\" is just going back to part of the code that behaves poorly and improving it to perform better. EDIT: a very simple software performance example (at least to me, not very ELI5, sorry) -- I write code to load a list of 100K words and search for a word in that code. Every time i do a search i search through all 100K words hoping to find the word or not. The word list is not in any order, I may find in the first 100 words (fairly fast), or in the middle (meh), or not at all (have to go thru all the words to determine that, yuck). If I somehow load the word list and SORT it alphabetically ONE TIME, then every time I search for a word, I can do a binary search (which is start looking in the middle of the list and see if my word is before OR after alphabetically - then keep going forwards or backwards by large chunks in the list based on the alphabetical order of the word i am looking for) - which allows me to find a word in 100K items in no more than 17 iterations instead of up to 100K iterations. The first iteration of my word search tool, is easy to do - 1) load list 2) search one at a time for word - the 2nd one is more involved: 1) load list 2) sort it (ONCE) 3) do binary search to find word. The second version of my tool is more involved to do, but runs much faster. & #x200B; With games though, maybe you have a very performant game engine, as long as you don't abuse how much data/object it can handle. In this case optimizing is changing data for the program instead of changing the code. Software has this issue too, in games it can be pretty important.",
"Speaking very generally: You find an area in the game that is suffering from bad performance. Then you use some tools called profilers to help you identify what is taking so long, and whether it is in your game's code on the CPU, or the the code you're running on the GPU. Then you test out some ways to fix it, and see if the performance improves. This whole process is called \"optimization\". As an example of a fix, maybe you find that the bad performance is caused by too many objects being rendered. You might decrease the draw distance of the area to fix it, or you might redesign your level to make it impossible for the player to see that many objects at once.",
"So one example of a way a game can be badly programmed and easily optimized would be for an open world game like let's say the elder scrolls... Now what if they loaded the entire world into memory at the same time? That would be a lot of memory they need to use when they don't need to, they ultimately only need to load the chunk you are in and a few surrounding chunks. An example of a game with chunk optimization is Minecraft where you choose the radius of chunks to load (I.e. If your view distance is set to 12 then you will see 12 chunks and as such have 12 chunks loaded into memory at all times) Another way games are optimized is by changing what they render... At one time games would prerender everything that was loaded into memory, but as more objects started appearing on the screen the became very inefficient. Now we commonly use a technique (that I don't know the name of) where you only render what the player is looking at. For my first link a picture example of what I mean shows up at 3:55 URL_0 Another method that a game can be optimized is by changing algorithms used to use one's that are less intensive... So say instead of diving by 2 you could use a right shift as it is almost the same as dividing by 2 but it happens much much faster. A left shift is shifting the integer register over by 1 position, so for instance in binary 0b10 is 2 and a right shifting it would cause the 1 to move to the right and as such we get 0b01 which is 1 (aka 2/2=1) There are way more... For instance what way we generate things like terrain and stuff is we generate millions of positions (using something like pearlin noise) and we connect them all and fill in the areas between to generate the land.... So to make it run faster we can remove some of those points from memory and we decrease the graphical load.... But at a cost of making the landscape look more jagged and less smooth. This can actually work with other things like character models and such but a lot of games (especially console games I find) don't do that at all. Finally a big optimization problem comes with unloading the memory, if the memory is improperly unloaded then you will eventually cause the game to crash by playing it too long (this is because you run out of memory, usually this is called a memory leak). Memory leaks cause the games functionality to decrease the longer you play it, regardless of anything else. Donkey Kong 64 was famous for having this problem, which is why it required the expansion pack, and as such only allows for a few hours of game time before you need to shut the console off. Without the N64 expansion pack the game would still be able to run perfectly fine... But it was only able to be ran for about 30 minutes to an hour before it crashed.",
"A game is like a big math equations. There are often ways to eliminate some steps to get the same result, or change a step so you can find the answer faster. This can also be done with games, but with a variety of different optimisation methods!",
"Game optimization involves the use of various 'creative' shortcuts to the game engine to reduce the number of times you have to ask the CPU (or GPU) to do something, or to do so more efficiently. At its heart, the CPU is like a tiny little calculator^+ . It can add, subtract, multiply, divide, and do certain logical operators (such as AND, OR, XOR, and NOT) on data very quickly, but not instantly. When you hear that a processor has a clock speed, of, say, 4 GHz, that is saying that the computer's clock moves 4 billion times per second, and that the computer can operate on that data (stored in binary as 1's and 0's) that many times each second. By optimizing the game, the developer is trying to figure out how to get the computer to spit out the right 'answer' with as few manipulations of the data as possible. One famous example of an optimization is the [fast inverse square root]( URL_0 ) operation. Inverse square roots are used by the game to determine where shadows and reflections should be placed, but taking a square root takes lots of steps for a computer to process, eating up many clock cycles. Instead, the developers found a clever shortcut to approximate this function to an accuracy that was 'good enough'^# to make the shadows look realistic, while only needing 1/4 as many clock cycles, freeing up the CPU to start the next frame faster, delivering a smoother experience to the player in the process. Game optimization is all about finding lots of these little shortcuts and tricks. Often, you don't need a perfect answer that takes lots of clock cycles, so if you can find a 'good' answer that requires less work, that's often going to lead to a game that plays better, even if the physics are not *quite* accurate to physical laws. They just need to be reasonably close that the player doesn't notice the subtle inaccuracies. \\+ Another thing to note is that modern processors are almost all multi-core processors, so it's closer to having 2, 4, 6, 8, or more little calculators all working at the same time. A major part of game optimization is to figure out how to split up the calculations in such a way that as many cores as possible can sit down and move numbers around together. Otherwise, you have one core doing all the work, while the other cores are sitting around, not able to help out and split the work. \\# Formally, the solution is approximating the inverse square root using the first-order Taylor expansion ln(1+x) approx= x near x = 0. The article explains in greater detail."
],
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|
9qh54j | What does a PoE/Power-over-Ethernet switch do? | Technology | explainlikeimfive | {
"a_id": [
"e895h75",
"e895uyp"
],
"text": [
"PoE means that the electricity required to power the device is sent over the Ethernet cable so you don't need to run an extension cord to wherever the device is in order to power it. This is especially useful for long-range wifi antennas that are in high-up or otherwise hard to reach places because you only have to run the one small Cat-5 or 6 wire up to it. A PoE switch is a switch that either requires PoE to power it or provides PoE to other devices connected to it.",
"Generally, Ethernet is used for standard communication across the network and the end point device uses its own power source. Such as an AC adapter plugged into an outlet. Power over Ethernet (PoE) allows for end point devices to use Ethernet connections for power. [Edit] Usually around 44-57 VDC. This is very useful for many simple devices like an alarm device or a phone. Eliminating the extra power connection, also simplifies installations in Remote places or where outlets aren't usually located, such as subfloors and ceiling spaces. [Veracity Global - POE explained]( URL_0 )"
],
"score": [
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"text_urls": [
[],
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"http://www.veracityglobal.com/resources/articles-and-white-papers/poe-explained-part-1.aspx"
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|
9qiake | How to add an image to a post | Technology | explainlikeimfive | {
"a_id": [
"e89k4gg",
"e89ei09"
],
"text": [
"Download the app imgur, make an account, make the image post, copy the link, then paste it your post",
"Questions like this are better in r/techsupport or r/reddit."
],
"score": [
5,
3
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"text_urls": [
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|
9qitmz | What causes long, straight lines in video recordings of bright lights like the ones in this video? | [ URL_0 ]( URL_0 ) & #x200B; At 3:25 | Technology | explainlikeimfive | {
"a_id": [
"e89lbkw"
],
"text": [
"Just too much brightness. In CCD sensors, when part of the sensor is overloaded, it bleeds over to the neighboring pixels. It's called [blooming]( URL_0 ) You can view the sensor as a bunch of water buckets that when they overflow, water flows into the neighboring ones."
],
"score": [
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"text_urls": [
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"https://en.wikipedia.org/wiki/Charge-coupled_device#Blooming"
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9qlcha | How can aliens listen to the golden record on Voyager 1 if they ever found it? | Assuming that someday they find it, how can they have the technology to play a record or understand it works? | Technology | explainlikeimfive | {
"a_id": [
"e8a2oil",
"e8a310f",
"e8acivn"
],
"text": [
"The record comes along with the device intended to play it, as well as instructions that are decipherable as long as they understand basic scientific concepts (which, if they are a spacefaring civilization, they likely will).",
"Included with the record is a stylus for playing it, as well as instructions on how to set it up and play it using fundamental mathematical and physical concepts. The assumption is that any spacefaring civilization advanced enough to intercept it would be able to decipher the instructions on how to play it.",
"**An audio record is an almost primitive form of technology that is not hard to understand at all**, if you are technologically advanced, which we can reasonably assume a spacefaring species to be. Just look at it (or touch it) and you immediately notice there is a microscopic structure. Look at that under a microscope and you see there is a single, long, spiralling groove with tiny wriggles all along it. Translate those wriggles to a graph, analyze it mathematically, and you see that there is a complex spectral pattern, sometimes only a few frequencies dominate (music), sometimes it's a wider mix (speech). It's not a big leap of imagination to translate that into vibrations, even before you do the mathematical analysis - and at that point you are playing the record. **The real open question is not whether the aliens can play the record, it's whether they have sensory organs to perceive vibrations.** If not, the audio might forever be a mystery to them. But it's also possible that there's a pretty straightforward \"translation\" of audio into their form of communication - for example, if they communicate with pulses of light, you can map volume to brightness and tones to colors easily enough. But if they do, they can \"listen\" to the record. There is almost no chance of them understanding the messages spoken in a large number of completely alien languages, but they could use it as a good starting point for communication if they ever come to meet us. And there's a good chance the musical parts with be meaningful to them as art."
],
"score": [
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9qlfzi | My FaceTime call is intercepting someone going about their business in their own home. How does that happen? | Technology | explainlikeimfive | {
"a_id": [
"e8a46ft",
"e8a4hxs"
],
"text": [
"I've only had this happen a couple of times, but never with FaceTime since I'm an Android user. Regardless, it seemed that in my situation the cell providers technology glitches and switches and /or combines audio streams. In both of my cases, it switched audio streams such that when I called the my original person back, we had both ended up suddenly talking to another person. Completely freaked us out the first time, the second was just annoying. For what it's worth, our carrier is AT & T.",
"Its not just on Facetime call, it happens in the populated Service Provider ranges. This is a common problem for majority of the network services. Unfortunately, i cannot explain or infact i barely know the technical side of it. Sorry my friend, i dont know why i typed this but just wanted to show my support to the community! Enjoy."
],
"score": [
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"text_urls": [
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|
9qlkbv | Why do TVs look worse from an angle? | Particularly LCD/LED TVs. The back-lighting and colors become distorted. Surprisingly, they still advertise 178 degrees viewing angles. | Technology | explainlikeimfive | {
"a_id": [
"e8a8cec"
],
"text": [
"The structure of an LCD panel [isn't completely flat]( URL_0 ). This isn't an accurate analogy in terms of structure, it's just the principle. If you imagine an LCD super zoomed in, think of it as looking down at a cityscape, all skyscrapers and such. If you look down at it directly from above, you can see the streets perfectly fine. If you change your angle and look at it off to one side, your view of the streets becomes obscured by the buildings, and you can't clearly see the roads, you can just get an idea of where they are. The further to one side you move, the less obvious the streets become. That's kind of what's happening when you view an LCD at an angle. The panels that allow a wider viewing angle have a 'flatter' structure, so the angle you look at them matters less."
],
"score": [
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"text_urls": [
[
"https://www.researchgate.net/profile/Jean-Luc_Duval/publication/310783356/figure/fig1/AS:434144682483725@1480519567062/a-LCD-panel-observed-from-the-top-with-an-optical-microscope-b-Structure-of-an-TFT-LCD.png"
]
]
} | [
"url"
] | [
"url"
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9qmsq9 | Does listening to music on full volume damage your ears if the sound is reduced by a loud ambient noise. | Technology | explainlikeimfive | {
"a_id": [
"e8ab3ws",
"e8ab8oy",
"e8agweq",
"e8af1wt"
],
"text": [
"If someone sticks a pin in your butt and someone else cuts off your leg you still have a pin in your butt.",
"Yes, the amount of db from your headphones remain the same. The 'reduction' of sound is merely an illusion. If you don't want any more damage done try to keep your headphones below 80db.",
"Yeah it’s really bad to ramp up volume to drown out ambient sound, you’re just increasing the amount of energy that your ears have to deal with. Ear damage is no joke! If you need music and are frequently in noisy environments, consider isolating in ear earphones, or headphones with active noise cancellation so that you can keep the volume lower. :)",
"Your ears perceive sound logarithmically. Look at the dB scale. If the background noise is loud, the sound to cover it has to be many times louder than that. You just have a overpowering sound that's louder than the background. Also, ear damage comes with time. Being constantly exposed to loud surroundings and loud music will make you go deaf faster than if you would be in a more silent environment."
],
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|
9qmta0 | What's wrong with Intel's 10nm? | Technology | explainlikeimfive | {
"a_id": [
"e8abq77"
],
"text": [
"Semiconductor manufacturing is an industry full of secret techniques and skilled manufacturers. They are basing it on lithography which is using light to change the chemicals in a film of material creating a patterned mask that masks out where you want the next process to happen. If you want some examples of this I suggest looking up PCB manufacturing which also use lithography but with precision measured in millimeters and not nanometers. When Intel have manufacturers who can make 10nm chips that means their manufacturing methods have a precision of 10nm. So if you have components that are spaced closer together then 10nm they might overlap which means the chip does not work. The issue is that Intel does not really have the ability to make 10nm chips reliably. They manufacturing techniques might have a precision of say 16nm. That means that if they try to make 10nm chips using their 16nm techniques it might work or it might fail. So when they test their chips after manufacturing they scrap the ones that does not work. They do have the ability to disable some cores in modern chips which is why you get odd things like 5 core CPUs which actually have more cores on the chip but some are disabled because they failed quality control. And naturally a dual core chip have less components which can fail so they can expect more of these chips to get through quality control. It is possible that Global Foundries have more accurate machines, better skilled workers and secret techniques which makes them more accurate then Intel. They might be able to output 10nm chips very reliable with most of the chips getting through the quality control."
],
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