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71q2m7 | How exactly does coding and programming work, and what is the simplest way to self-teach? | Technology | explainlikeimfive | {
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"Essentially, you give the computer/browser instructions on what it should do. Generally speaking, the computer has no idea what to do unless you explicitly state it. There are many different languages suited to different machines/devices. For example, a web server can run any number of backend (server side) languages, like Ruby/Python/PHP/JavaScript. These instructions on the server let peoples browsers know what to display for certain users. As far as learning goes, there are a pretty wide array of choices online, and a lot of them are free (and some are quite good). Examples are Codecademy, Free Code Camp, etc. once you learn the basics, the best way to get better is just to build stuff. And build more stuff. And keep iterating on that."
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71q4yx | How can games become "broken" after patches and updates? | R6 Siege recently underwent a major update where they fixed bugs, issues, adjusted recoil, removed content, etc. Post update a whole array of game-breaking glitches have popped up, and I have no idea how this - on a technological and practical level - is possible? For example, some new post-update glitches have enabled players to fall through the map, glitching between walls and exploiting it to kill other players etc etc. - How does fixing netcode enable this to happen? - Cause I presume they don't go in and patch basic code from launch date? | Technology | explainlikeimfive | {
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"> Cause I presume they don't go in and patch basic code from launch date? Why not ? That's what they do. Modify the existing code in an attempt to make it better. Sometimes making improvements means rewriting most of the code: the new netcode has its own set of bugs.",
"You ever try to make mac and cheese that turned out a bit too creamy, so next time you take out the butter and instead of tasty macaroni you end up with a burnt pile of shit? That's pretty much what happens. Making a game involves hundreds of thousands of lines of code and millions of instructions that all need to be written perfectly. Sometimes a dev might be up late one night writing code for how characters interact with textures and in their fatigue confuse a ; for a :. If the program doesnt pick it up, it goes unnoticed until you use that line again three years later and suddenly a normal map is now a portal to the fifth dimension.",
"When a car gets a new model, it's usually better, but sometimes, the engineers have made a mistake, and there is a problem. They used another material in the radiator hose that was cheaper and takes wear and tear better, but failed to check how it handled when the temperature drops very, very low because the engineers work in a warm region. So, suddenly, it gets brittle and develop cracks and starts leaking. The planned improvement was actually a step back. Same with software. You make changes, and sometimes, those change contains mistakes. Software is very large and very complex, so it's practically impossible to test everything. Even if everything works in your environment, suddenly someone tries to run it with some odd configuration on an uncommon graphics card, and that causes problems with some graphics optimization you've made. Obviously, you can't test on all possible combinations of hardware/software/OS/drivers, so you'll have to take a calculated risk. Most of the time it works, sometimes, it doesn't."
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71xn1o | Why does "HD-ready" 720p TV panels have a resolution of 1366*768 rather than a 1280*720. | This is something that's been haunting me for years (720p yo!) and since I', already posting stuff in eli5 i might as well post this. It makes everything connected except a computer run at a non 1:1 pixel ratio. It really makes no sense to me. | Technology | explainlikeimfive | {
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"1366x768 is a standard computer resolution. This allows manufacturers to sell the same panel designs as both monitors and TVs. An actual 720 panel isn't very useful for PC use because lots of things assume at least 768 pixels high (it goes back to 1024x768 being the lowest of the \"high resolution\" modes)"
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71yck4 | Why doesn’t the United States have a high speed rail system? | Technology | explainlikeimfive | {
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"When it comes to rail in the U.S., there's basically two places: The Boston-New York-Philadelphia-Baltimore-Washington corridor, and the rest of the country. Rail used to be the main way to get between cities in the U.S., but the Interstate offered faster and more convenient travel for those with a car, and really long distances like going from one coast to the other can only be done quickly by air. (For instance, even the fastest high-speed trains wouldn't be competitive for the New York to Los Angeles route.) Amtrak, the national rail company, doesn't own its tracks in most of the country, so its trains often have to wait for freight trains to go first. Coverage and routes are limited. If you live in Memphis, you can go to Chicago fine, but getting to St. Louis might take days even though it's only four hours by car. For the big cities between Boston and Washington, rail is still ideal. Traffic is bad, many people don't use cars, and airports are far from the city center. Traditional rail still does pretty well, and high-speed rail would be incredible. There's still two problems. One is crash-test regulations, which force trains to be heavier and slower than foreign counterparts. (Other countries don't have such strict regulations; rail collisions are quite rare, and traveling by train is much safer than by automobile anyway.) The other is simply the cost of building rail lines in that area which can handle high-speed rail. Amtrak's proposal for true high-speed rail in that corridor is projected to cost over $100 billion.",
"Population density. The population density of France is about 300 people per square mile, and that's one of the lower values for Europe. Germany is 600, Italy is 500, Netherlands are 1000, UK is 700. There are only 8 US states with a population density above 300/sq mi, and except for Florida, all of them are in the Northeast, where the US does have [something resembling high speed rail]( URL_0 ). 35/50 states have a population density less than 200/sq mi and 24/50 are less than 100/sq mi. So it's just too few big cities too far apart. You could maybe extend the existing Northeast system south to Charlotte, NC and west to Detroit or Chicago, but after that, the number of big cities starts dropping off pretty fast.",
"There are a couple of reasons, all of which are covered very well in this [video by wendover]( URL_0 ). Population density is partly to be blamed but there are certain routes (eg DC to Boston via Philly and NY) that would be perfect for a high speed train. There is an existing rail system and in fact it has been doing very well. Amtrak is a company that was created with the aim to make \"train travel great again\" and to build high speed trains in the future. Unfortunately ~~it is fairly new and other~~ *freight* companies already own the train tracks and Amtrak has to rent it. Comparatively, the SNCF in France owns all the tracks in France. So now, if BNSF has a train on the tracks and there is an Amtrak train coming, the latter will have to wait for the slower train to finish first. You end up with a cyclic problem of the train suck and with people thinking that it sucks, less income to improve it. Building new tracks is extremely costly and is not really a project that any sane person would like to undertake. Edit: BNSF not BNCF and strikethrough/italic Hopefully we get the hyperloop though and that will be amazing.",
"Lots of comments here. One I haven't seen mentioned: The US has the most efficient and heavily used **freight** rail system in the world. [Economist]( URL_0 ) We have a lot of rail, we use it for moving stuff rather than people. The transcon mainlines move a crazy amount of cargo. Hundreds of trains a day like [this]( URL_1 ) going across the country on them. Moving stuff efficiently and moving people efficiently are largely incompatible. Freight efficiency means huge, slow (comparatively) trains. Moving people efficiently means high speeds. You basically can't mix a lot of both on the same tracks and get anything useful out of it. Europe opts using it's rail primarily for people, we use it primarily for stuff.",
"Enough of our cities do not have self-contained public transportation so HSR between cities will not be convenient enough to deter people from driving. This is because once you get to a city, you still need to get around. Although you can Uber, the combined cost of HSR ticket and Uber make the convenience of driving yourself the \"best\" option. Before we invest in HSR BETWEEN cities, IMO, we should invest in building public transportation WITHIN cities.",
"I believe it's about size/density of the U.S. In Big European countries (France, Germany, Spain etc...) the maximum distance between 2 cities is around 1000 km, so 3-4h by train (Against 1h by plane + Time to check in + Time go go the airport). So with less than 1000 km or railroad you can cross the country and link 2-3 big cities. With 1000km of railroad in the U.S. you might go from Dallas to Atlanta and have no significant city in our way so there is no economic advantage in offering stops in the way. In European cities, the center is quite important people live and work their so if the train drops you from center to center and save you a 1h drive from/to the airport. While in the U.S. cities are acentral",
"The answer to a lot of \"why isn't the US more like Europe\" questions (not all, but a lot) is because a lot of things are easier when you have a smaller, more compact country. Generally everything to do with infrastructure, like giving everyone high speed internet, transport, services.",
"Acela is a (relatively) high speed train that goes along the Northeast corrider but the trains don't actually go as fast as they are able to because of a combination of old tracks on very curvey routes, and a very small engineering flaw that resulted from bureaucratic/political meddling. When the Acela trains were first being tested, there was a political decision made that being high speed trains they needed to be extra safe in the case of an accident, so they were changed to be a quarter inch thicker. (Edit: it's actually 4 inches) This made the trains safer but the increase in width was just enough to make it so that when the trains took turns at high speed and lean a little, they would collide against each other. Whereas they had originally been designed to take yaw into account and the original width allowed them to pass each other. So thanks to political meddling and safety theater, trains that are actually capable of going at much higher speeds can't actually do so because the extra thickness added for safety would cause them to collide. Lol",
"A big part of this actually stems from oil, auto (General Motors), and tire companies forming cartels and buying rail tracks then destroying them. Since a lot of these transnational companies that had a ton of power were based in the US they were able to stall the rail systems in America, which is why America drives more cars than most other countries today.",
"Land use. We have had basically no land use policy and so all of the land around major cities has been developed, making it very expensive so buy it up in a straight path to make a new train line. Compare this to European countries that don't have as much automobile suburbs. They are able to build them much more cheaply.",
"There's two answers, nationwide and regional. Regionally, we don't have high speed rail because of lack of interest. Amtrak has few corridors of normal speed rail that are profitable and nice (like SoCal and the NorthEast) but are prohibited from purchasing track and taking priority routes. So they can't grow. We spent the 50s and 60s massively investing in car infrastructure, to the point that building a high speed rail AND getting people to ride for it to be profitable would be difficult. In Europe after WW2, people were poor and lived in high density areas, so rail was a common option to get from city to city. In the US, we had relatively high levels of wealth coupled with white people moving to suburbs, and suburbs don't lend themselves to trains. Nationally, it simply comes down to population density. We have huge tracts of unsettled areas. In terms of cost per mile, air travel is actually a better option. The biggest limit to air travel is security and other \"on the ground\" stuff that slows me down. Wheels up to wheels down I can get from Denver to Los Angles in 90 minutes on a good flight, and cheap airelines can operate that flight for $45. There's no way rail can compete with that.",
"Rail's downfall is that last leg from the station to home/destination. Ultimately you have to get a car so you may as well just drive. Then when you are there how are you getting around? You need that car in America or your life is over.",
"American culture is the reason why we don't have a high speed rail system, or much of any public transportation systems for that matter. American culture has throughout history favored individual property/values over communal property/values. This includes transportation. Part of the \"American dream\" is owning your own car and having the freedom to drive wherever you want to go.",
"There's Amtrak, but otherwise it comes down to money and politics, much like many systems in the U.S. In order to upkeep a nationwide high speed rail system, you'd have to raise taxes, because in the current state of public transportation, no sane private company is going to undertake a transportation system of that magnitude. Even Amtrak is partially government funded. But no politician wants to raise taxes, therefore projects like improved transportation can't be approved due to budget constraints.",
"The answer to this question is the same answer to \"why doesn't Los Angeles have better public transportation?\" Auto industry. They spend lots of lobby money to make sure they stay in control and make sure people rely on cars and gas instead of alternative transportation options. If you could hop on a high speed rail and get from Chicago to St. Louis in 2 hours, then you wouldn't be driving or spending money on gas. People in this thread point to population density and the large distances between cities. Yeah, the reason for a high speed rail is to travel large distances quickly so why would that be a deterrent. High speed rail could've happened but auto industries (bailed out by the government) and oil industries (have shaped political agenda for years, see Koch brothers) have too much control to let something like that happen. If you were to propose high speed rail today, they'd pay politicians to shoot it down and pay for ads and propaganda to give it a negative image to the public.",
"The US is enormous and that has a lot to do with it but, there is no way in hell that the oil and automotive industries would let that happen.",
"In addition to what other people are posting about land and how the US is highly car-centric, many places are super far away and while people mention this, they don't really show why this is a factor. The Fastest high speed train in the world has a top speed of around 430 km/h, which is a snails pace compared to a regular old passenger plane which flies at 900km/h in a dead straight line to the destination.",
"Basically, HSR works best for trips that are ~150-500 miles. Anything less and people will drive. Anything more and most will fly. Consequently, there are only a few spots in the country that fit this distance. Boston-DC is one. I could see one being placed in the midwest with Chicago as the hub going to Milwaukee-Minneapolis, St. Louis-Memphis, Grand Rapids-Detroit-Cleveland and Indianapolis-Cincinnati. And the west coast going from San Diego up to Seattle or Vancouver. Another thing that has prevented it from occurring in the past is the fact that ever since the interstate came to be, cities have sprawled out make true intercity rail unusable. You could ride the train into Dallas, for instance, but you would most likely need a car when you got there. Whereas in Europe and other similar places, the train stops in the city center and there is enough density and transit that the car is unnecessary for most people let alone visitors to a city. The last thing I would say is that the US is so spread out that a true national high speed rail system wouldn’t work for the vast majority of the country just because of the sheer distance between places like Kansas City and Denver, for instance. The cost of building new rail wouldn’t make financial sense for most of the country. The only way I see it happening is if a private company does it all by themselves or there is some sort of public-private partnership.",
"The US and Europe are about equal in land mass. However when it comes to population density, it's a much different story. The total cost per person for the same amount of lines built would be drastically higher in the US. Also the amount of people it serves per square mile would be reduced. Realistically for the US's population density, it doesn't make sense....yet. American culture also favors owning your own things and doing things the way you want on your own time. If I want to right now I can pack whatever I need and travel wherever I want in the continental US and not have to fight anything or go through anyone to do it. Solution that solves both problems. Tesla is testing out hyperspeed tubes for travel that can take individual vehicles (much like a tow boat.). This can solve both problems.",
"OP's never heard of Brockway, Ogdenville, or North Haverbrook? High speed monorails put them on the map.",
"Part of it is that conservatives are ideologically opposed to public transportation. In Wisconsin, about 7 years ago, the federal government gave our state about $900 million to build a high speed rail line going from Minneapolis, Minnesota through Madison and Milwaukee, on down to the Chicago, Illinois. But when our newly elected Republican governor took office, he promised to \"kill the train\". He told his rural constituents that the train was wasteful \"big government\" designed to benefit only big city liberals. He said that he would do the same thing that Sarah Palin had done when she said \"thanks but no thanks on that bridge to nowhere\", and strong-arm the federal government into giving the state the same $900 million for spending on roads. He exploited the notion that public transportation is socialist and that cars are more in line with personal freedoms. His additional rationale was that he would save the state about $7 million a year on upkeep costs to keep the train running. Well, after he killed the train, the federal government took their $900 billion back and did not return it. Additionally, instead of saving the state money on maintenance costs, Wisconsin actually has to pay something like $60 million to various contractors in order to back out of construction deals that had already been made to build the train. Since then our state has lagged far behind its neighbors in job growth.",
"Because the US is a big fucking country with a much more widespread population compared to the countries that do have high speed rail.",
"I wish they would build a HSR from Chicago to Detroit, maybe one or two stops between. Somewhere around Kalamazoo (for one) or Jackson and South bend (for two). At 200mph, you could commute from Kalamazoo to Chicago or Detroit faster than you can drive commute from Gary to Chicago or Jackson to Detroit. The real problem is anyone wanting to invest that much money into such a project and the state/local governments willing to help plan/permit/provide tax incentives such a project.",
"Nobody can afford to pay to create the required infrastructure. Existing track can't just be used for a high speed system. New tracks would have to be created with appropriate inclines (slopes), curves, banking, etc. and that would all have to take place presumedly where there are high populations of people who would be the riders. Well, the cost of acquiring the required land in urban areas would be immense. Meanwhile, most major metropolitan areas are struggling financially to keep their services going, cover their employees' benefits and maintain existing infrastructure.",
"The only place in the country where train travel is currently popular is in the Northeast Corridor (roughly, the Atlantic coast between DC and Boston). Pretty much everywhere else is too spread out. There are some in the works, though. California is trying to link LA and SF with high-speed rail. There's also a proposal in the works for a bullet train between Dallas and Houston",
"My take: Because the idiots who have run Amtrak in the past have soured the public on rail travel. For example, when we lived in Orlando around 1983, my wife checked into taking Amtrak to Houston. She would have had to travel from Orlando to Washington, D.C., West to Chicago, and then South to Houston. It would take 3 days and cost twice as much as a plane ticket! This despite a large system of rails across the south. On the brighter side, a HSR system is being seriously considered to connect San Antonio-Austin-Dallas/Fort Worth.",
"ELI5 - with the population map America has, high density in cities and Big space between them it doesn’t become feasible because railways are a lot to maintain. They require labour and money. That being said currently under development is the California HS rail link planning to go from LA-SF if I’m correct?",
"The primary answer is that European cities are old and US cities are not. And newer European cities adapted to their dominant model, while US cities didn't have to. The key element is the car. Pre-auto city hubs are different than US cities, and anticipate travelers not needing a car. US cities, other than the oldest, depend in their geographical logic on everybody being independently mobile inside the city. Since you need a car when you get to a US city, you bring a car to a US city.",
"Nobody here has mentioned that California is currently building a [high speed rail]( URL_0 ).",
"Because our country ia massive compared to anywhere who does have one and its not really practical....",
"The auto industry has had a very strong lobby for the last 75 years. So had the oil industry.",
"Becuase generally, one has to drive at one point of the trip. Much of the non subway passenger rail is city to suburbs which are not walkable. It lowers demand since you can't effectively rely on the system completely.",
"Everyone wants a highspeed railway system lIke Japan, right? Well, The entire country of Japan fits snugly inside the state of California. Which is one of 50 states, some of them larger still. Why can't the US have a bullet train system like Japan? Because that country is so tiny compared to us that it's not even funny, and the cost of building something simillar here would be so large that we might as well purchase Japan and get it over with.",
"Lobbyists and old money from old companies not willing to invest $$ into R & D. Even China has high speed rail. They also lead in renewable energy. Oil and coal lobbyists hired by big oil and Koch bros keep America from properly planning for the future. We also have this system of gov't where you elect people who receive bribes instead of actually representing you. URL_0 URL_1 Americans love to diss China \"en masse\" but they are far more advanced than us in more ways than we think.",
"I think one huge reason I've yet to see posited in this thread is the lack of schedule cars and the interstate system provide people. Americans like to go from A- > B at whatever time they should choose too, without regard to someone else's preplanned routing. It's 3am, and you would like to be in Memphis by noon, not a problem for me by car, HUGE problem by rail. While rail can certainly transport people/cargo more efficiently, the need of long pre-determined, confined to the rail, routes is not what most Americans enjoy. I can't find the quote I'm paraphrasing; \"Americans like to go hither and yon, without a schedule, without being confined to a predetermined route.\" We also like being able to make the proverbial accidental left in Albuquerque, because it leads us to new places, we didn't *plan* on being.",
"Because it's focused all its money on a high speed *JAIL* system, am I right????",
"Rail is best for connecting densely populated neighboring cities. US is large and sparsely populated.",
"Probably why Russia and Canada don't have them. Huge distance and costly compared to Japan or other European nations.",
"Here are a few other ELI5s that might also help: * URL_2 * URL_1 * URL_4 * URL_3 * URL_5 * URL_0",
"The republicans vote against it every time, therefore preventing the funding from going through. This is the real answer. They do this because they want to provide an unfair market advantage to big oil.",
"We used to have a decent rail system (in the 1800s) However, those trains ran on coal, and when the automobile was invented, it ran on oil. Oil companies lobbied the government to invest in highways instead of railways.",
"The existing rail system is owned and maintained by a small amount of companies and they have all they power with respect to their rail road lines. They give their trains priority. Nobody wants to pays billions upon billions in infrastructure for a new system.",
"It costs a million dollars to put down a mile of track and America is about 3000 miles long. It would cost an enormous amount of money and take a lot of time when flying is usually cheaper. As awesome as it would be to have high speed rail. (Source: buddy-guy I know works on the railroad.)",
"There are some good answers here and there are some poor answers here. The main reasons there is no high speed rail (hsr) are: -you keep electing bad politicians into positions that could say yes to high speed rail. -most Americans dont understand what hsr is and what the benefits are, or understand the costs in context. -us law sends lots of money to any small or large new build Interstate program regardless if the return on investment is actually negative, yet getting funds for new hsr requires lots of politicians to sign off on it and most veto it as they see that as being in there best political interest. Yes the population density is low in some places but there are lots of big cities that are less than 3 hours away at 150-200miles apart, and if there is little inbetween you can build hsr relatively easily."
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7208pw | How do software updates like iOS11 speed up the phone? | How do software updates speed up the app transitions, closure of apps etc. In my very basic knowlede of computing, the hardware, dictates how powerful/fast a .device is | Technology | explainlikeimfive | {
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"The hardware will determine the maximum performance. How fast a app or the operation system depends on hot the program code is written. There are multiple ways to write code that do the same thing and it is usually the case. The simplest and fastest way write code often will result in a slow program. If you spend more time on the code you will likely find a faster way to do it that might be more complicate but the program will be faster. Here is a [BBC video]( URL_0 ) that in a simple way explain that that different algoritm can take different time to do the same thin. It it not exactly the same as how speedup of a OS works in most case but is illustrates in a nice way that the the speed of a programs will depend of how it is written. It is often the case that the program that translate the code to what runs on the hardware (compiler/interpreter) get faster. It takes time to optimize it for a new CPU etc and the engineer that writs it have now had time to make it faster. There might also be another reason is that for different reason the phone gets slower and slower over time because of how data is stored etc. It might be the case that a"
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721kim | Why do car windows shatter so much differently then normal windows? | Technology | explainlikeimfive | {
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"they are tempered. means the surface of the glass is under constant tension, so when the pane is compromised it all shatters into harmless chunks. It also makes the glass harder and more resiliant to temperature variations. You cant cut glass after its tempered (or its very hard/risky). All in all, the cost isnt always worth it. The front window is further laminated, 2 panes of glass sandwiched around a fancy peice of clear plastic. So even when broken, it still maintains most of its structure to keep things in or out.",
"Front window is laminated plain glass. Side windows are tempered glass but not laminated. That's why front windows break and run but don't collapse inside but side windows simply explode into bits"
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723yfv | why do we have so many types of screw/screwdriver? Philips, flathead, hex, square etc. very annoying to have to keep so many types of screwdriver. | Technology | explainlikeimfive | {
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"Real answer has to do with torque and cost. Flat head screws are the absolute cheapest to machine, but you can't apply much torque before your driver slips out. Phillips head are better in the torque department, but cost somewhat more to machine. For the most part, the more torque you can apply to a screw, the more intricate the head is, which means the more time consuming it is to machine, which means it costs more to make. For you, Joe Hobbyist, a few dollars difference between a box of flatheads and a box of torx might not matter, and you could use torx screws for every project if you were so inclined. For John Industry, who needs to buy thousands if not millions of screws on a regular basis, the cost differences add up. They will hire mechanical engineers to determine how much torque they need to achieve the spring force necessary for the job (screws are springs that get stretched when you turn them, and use spring force to pull two objects together). A torx screw may be \"better\" but if those engineers calculate that a flathead can get the job done at 1/4 the cost, and meet safety standards, then they use flathead.",
"There are a couple reasons that I know of. One is purpose. Drywallers for example use (almost) exclusively Phillips screws. They release from their bits quicker, and because drywall and wood offer little resistance, you don't have to be concerned about their tendency to strip much easier than other screw heads. Hex heads are often used when a lot of torque must be applied. Flat-heads are only used nowadays if something is intended to be tightened by hand. Another reason is tamper-resisting. Often times manufacturers will use torx or other goofy-shaped heads to deter the average joe-blow handyman from taking something apart. The last reason I can think of is regional. I know in Canada, many screws are Robertson (square) but almost none are in the United States.",
"The most annoying are those which appear almost identical, but are not really compatible. - Phillips and Pozidriv are very similar (esp. when painted over), yet you'll often cam out the screw if you mix them up. - Metric and imperial hex head fasteners and wrenches are even worse. Use the wrong one, and enjoy your round head screw. Worst of all, there is *no good reason* for having two different sets other than stubbornness. - Torx thankfully doesn't have metric or imperial versions, yet they have an only somewhat compatible variant called torx plus.",
"Robertson is the square and it was made by a Canadian and we are proud of this so get the name right please",
"Good answer above, is also related to safety. As in IP ratings define access without use of special tools (also mentioned above) to deter untrained persons dismantling or attempting the repair of products."
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725712 | Why does turning on Wifi on your phone improve location accuracy? | Technology | explainlikeimfive | {
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"It takes time to put together your location using GPS. Your phone can reference a database of locations and MAC addresses of WiFi networks much more quickly."
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726vt2 | how do devices like phones, tablets, etc. get the signal to turn on when you push the power button? Is there still some power being used to do this even when they are off, or is the process mechanical when you hold the power button to turn on? | Technology | explainlikeimfive | {
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"Around 1995 when I got my first computer it had a mechanical switch that turned the computer on. The power supply had a thick wire that ran from the power supply to the front of the case to a switch that then ran back to the power supply. In order to turn the computer on, that switch needed to be closed to allow the main current to flow in the first place. This makes it much like the light switches in your house, where first the current flows to the switch, and from there to the light fixture. A few years later I built a new computer that had a slightly different setup for the power situation. Instead of the big black wire carrying main current to the switch, it had a very tiny wire and the power supply itself had a switch. Essentially the 'hard' switch was moved the the power supply and it was replaced with a 'soft' switch. The advantage of having this soft switch was that it was one of many ways of turning a computer on/off. Other means of doing so included an internal clock set to a time, a key stroke/mouse movement or a packet coming in over the network interface. These soft switches were often prefixed with the name \"Wake on\" (ie Wake on LAN) URL_0 In the ATX standard this is accomplished by a few special pins between the power supply and the motherboard. The 5V Standby line supplies a small amount of power even when the rest of the power supply is \"off\". When you push the power button on the front of the computer, this shorts out the 5Vsb line that leads back to the power supply via the PS_ON pin. The power supply then begins to stabilize itself for a small amount of time before sending another signal back to the motherboard via the PS_GOOD pin. Once this signal is sent the computer then begins booting up. For devices like phones and tablets, while the standard might be different, the process is much the same."
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726zmc | Why is it when you angle a screen away from you, it gets darker and changes colour? | Technology | explainlikeimfive | {
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"Shine a flashlight through a toilet paper roll. Of course you can see the light clearly when you look directly into the roll. But when you look at it from the side, you can only see the illuminated inner side of the roll, not the light itself. So the light you now see is different, dimmer and probably a bit distorted. Your screen is very basically millions of tiny rolls next to each other. When you look at the screen directly, you see the light through the rolls. When you look at the screen from the side, you see only inner sides of the rolls."
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7286qb | Why does Samsung release a less powerful version of it's phone in the USA then the rest of the world? | Technology | explainlikeimfive | {
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"One of the American carriers (Verizon I think) use a specific cellular band CDMA which the more powerful exynos chips don't support. Samsung has to use Qualcomm chips instead for North American models which are less powerful but support the CDMA band",
"Some provider in USA use CDMA. Maybe that's why they use Qualcomm chips or whatever it was."
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7286r0 | Why do social media ads change, through seemingly uncorrelated events? | I work as a nanny, a job I recently started. I went to the house and the girls wanted to watch TV so we turned on nickelodeon. two days later, all of my instagram ads are for shows like iCarly and other nickelodeon shows! This has happened multiple times before, where events that happened in my life which I did not search or send through my phone at all somehow end up as ads. It is spooky as hell. any ideas as to how instagram/facebook gather their ad data and use it? | Technology | explainlikeimfive | {
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"Via the microphone, your phone “heard” the sound of the shows, matched them in a database and then delivered the ads slated for that demographic. It uses the same mechanism as Siri or Ok Google or Alexa and the same speech recognition. For example, my wife and I were talking about fried chicken for dinner. Later that evening her Facebook was crammed with ads for KFC. You’re right, it is spooky. It’s why I disabled Siri. She never had anything interesting to say anyway.",
"Somewhere between psych effect and Siri listening to your conversations: Once you connect to home wifi, you’re associated with that IP as a guest or family member by automated ad bots. A profile has already been established for the family’s IP as a “family with kids”. Now you’re served more relevant ads."
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728eh9 | How is Linux more customizable than other operating systems? | Technology | explainlikeimfive | {
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"Linux is \"Open Source\". This means that you can easily access the raw code that the OS is built out of, and edit it as you see fit. If you have relevant skills as a programmer, you can change literally everything about the operating system. If you compare that to something more commercial like Windows or Mac OS, you don't have those options. The operating system was compiled by the manufacturer and released as a finished product. You can't even see the code, and have no option to edit it. Think of it like cakes. Buy a Linux cake and you get the cake, and the ingredient list. At any point you can easily take that recipe, tweak it to your heart's content, and make another cake. Buy an MS or Apple cake, and you just get a finished cake.",
"I'll approach this from a different standpoint, I personally tell people frequently that I bled and sweat and cried my way into Linux. It wasn't an easy thing at first, I started around 2008 with Mandriva Linux, which I borked repeatedly due to inexperience and computer inexperience. I gave up, and returned a year later with Ubuntu linux, of which I use regularly. It wasn't easy, I was used to being catered to by 90% of the world I knew running on windows, so finding help for Linux was harder. It didn't help that I didn't know how to search for help for linux for quite sometime either. No Linux is not my main machine at home, but it is at work, so I get a good 50/50 out of it. (Windows at Home for games, Linux for IT work at work.) Linux is Open Source, as many here have pointed out, and it's very customizable. If you know the right code, and have the right skills, you can change it to your liking, in any way. As long as you follow the Open Source license and release the changes. (This is generally easy, as if you contribute to any open source project your changes will generally be very open to view, I'm looking at you Github.) But onto the meat of it, Why does open source mean better for us? Me and you? Because it means that while I can edit this code, Everyone else can too. This means that even if I never do, I can use the internet to find a great deal of many people who *have*. Say, that I don't like how my desktop is laid out. (I don't like where my start button is, or I like how a Mac laptop is laid out.) I can go online find the appropriate command, and download and change it. It may take a little time to download and install, but the options are available. I can choose between quite a few: KDE, Gnome, Enlightenment, Unity, Mate, LXDE, just to name a few! This goes for Software too. Because the internals of the Linux Family of Operating Systems are open, we get choices on almost every level, far beyond the ones that Windows gives. This is something some people love to an extreme degree, and naturally have strong opinions on the matter. Lets list some examples: * My Task bar is too big, because I have a tiny laptop with a tiny screen, with linux you can look up how to make your task bar as small as you'd like, and still hold your icons. Maybe you don't want a taskbar at all, and want a Mac-like dock? Linux lets you do this. * My computer is running very very slow, windows just takes too much for it to run, I can find a version of Linux that requires much less power and will run and make my computer act brand new. * I want my computer for a very specific use: I only want it to run google chrome, nothing else ever. You can set up a computer with Linux to do just this one task, and nothing else. * I want to make [Google Deep Style images at home]( URL_0 ) I did this one personally and I love it, I crank them out on one of my servers at home, and it's a fun gift to give to people from time to time who've never seen it. This one is harder though, so I'd recommend a newbie keep clear of it for a little while at least. In my line of work, I often tell people to simply get something that you will enjoy working with. If it's a Mac, a Windows machine, or a flavor of Linux. Do what you need to be productive on your machine, but keep an open mind and try other things. You never know what you will find on another piece of Software, or Operating System that may blow your mind and change everything about how you produce whatever it is on your computer. I find myself working fairly well on any of the big three. I've poked around with BSD and may in the future make it a work machine so I can learn it more forcefully. The last thing I can offer is this: If you are curious to learn Linux, I'll tell you the biggest three things I learned that helped me get familiar with it: 1. Dive in, and don't be scared of problems. Use google to find solutions and begin to learn how things operate. In time you will find yourself getting more and more familiar with it. This is much like learning Windows for the first time, not a lot will make sense, but as you notice patterns, you will begin to understand how this works. View it as an adventure, and do a little reading before hand so you know where to start. 2. Find an aspect of the OS you enjoy and play with it! I learned to love the Command line, customizing how it looks, and having it do things I used to use a mouse to do or my love of SSH which lets you control computers across your network at home, or even across the internet. Maybe yours is Games? Or perhaps it's seeing what kind of different software you can try? I learned about my favorite Linux Software [youtube-dl]( URL_1 ) via [youtube-dl-gui]( URL_2 ) which is a program that makes it easy to use and downloads any music you like from Soundcloud, Youtube, and many other places. It was a god-send for my music collection when I found out that youtube-dl works on sites that aren't youtube. It will even let you download just the audio from videos, so you can collect music. I do know that it's available on Windows, but I learned about it because of Linux. 3. Vocabulary! Be sure to ask people about linux functions and see if they have a name you can search for. I wanted to run programs on each of my processors at once. I had no idea what this was called until I asked on the Ubuntu forums and I was told I was looking for something called Parallelization. This then let me google more effectively. This is 60% of the battle. The rest is all implementation. And three warnings: 1. People who google are people who get answers, also take a look through /r/unixporn and subs that focus on Unix/Linux specifics like Unix coding, or linux command lines, or subs dedicated to specific distros. The Forums dedicated to specific distros, like the legendary Ubuntu forums also will offer help for even the smallest questions. Feel free to ask, and search through them, usually people have had the EXACT same problem you've had, you just have to find how they fixed it. I forced myself to use linux exclusively, it took two months and before I knew it, I wasn't thinking about how much trouble this was, I was just browsing the internet and playing games I knew could run on Linux. (And doing my IT work at home.) 2. If you have an older wireless card (USB, onboard, etc.) or certain video cards, be prepared for the possibility of incompatibility or some stretching to get them functioning. Looking them up using google before you install will save heartaches. Of course you may luck out and they may just work without any sort of tinkering. 3. If the distro you like offers it, RUN THE LIVE CD, which means simply that you are running Linux off the CD, or USB drive and taking it for a test drive. It is the full version of the Operating system, but temporarily, this allows you to figure out a lot of the worst problems before you make the jump. I work a lot with people who have never used a computer before, and fixing computers for people who only have used them lightly. Feel free to send questions my way if you are genuinely interested in learning Linux, I'll offer what help I can, and point out sites that I used to learn it.",
"For Windows and MacOS, one company built the entire thing as one integrated experience from the ground up. They could make everything integrated together. For Linux and UNIX, one organization made a command-line OS. Then another built a base GUI system, X Windows. Then a third created a widget toolkit. A fourth created a desktop environment. And then someone else made a different kernel, which is the program that manages your hardware and determines what programs get time on your CPU and get memory and things like that, because the existing ones weren't open source so you had to pay AT & T a lot of money to alter the kernel to your needs, which we needed to do back then. And then someone else made copies of all the basic utilities you need to have a usable command line only OS because the existing ones weren't open source. And then several people created different widget toolkits because the existing ones were crud. And on top of that they built a few different desktop environments because they needed them and couldn't agree on the best way of doing things. This created a lot of choice on how to set up your computer. So now you've got a bunch of people who are pretty particular about how their computers should be set up, and they know their opinions differ from each other. But they don't want to duplicate tons of work by each maintaining effectively identical software that differs only by what color it is, or what key sequence saves a file, or which side of the window the close button is on. So they added theme support and rebindable keys and configuration options -- a lot more than Macs or Windows. And then the GNOME Desktop Environment decided that it should ruthlessly curate its configuration options, removing any that the core devs didn't find useful, and they found fewer useful with each release. Eh, it's a general trend that Linux stuff is configurable, not an iron law.",
"Because a \"Linux\" system is composed of many individual software projects, and these have all developed to play nicely with each other. Every so often someone becomes fed up with one of those projects and decides to make their own. There's multiple desktop environments, windowing systems, software libraries, etc. etc. At some point, someone has made an alternative to just about every piece. The end result is that these \"pieces\" are generally well-contained, because they keep getting ripped out and replaced. So while on a Windows system, where the graphical environment is strongly integrated with the whole, it's not easy to use a substitute, on a Linux system, where there have been many different graphical environments, it's much easier. The design has evolved over the years to be modular by the nature of how it was developed.",
"You might want to work on your delivery. from /r/linux/ *I literally asked the question above and got shit on for no reason. That tends to make a person more hostile towards those who are rude.* --Jkrollinup *Go fuck yourself* --Jkrollinup *Yes dipshit. It's a project for my computer class where each group gets a major operating system and argues why it's better. Go fuck yourself* -- Jkrollinup",
"Your account is new and only 3 posts on it. There are a lot of trolls going to /r/linux so maybe they thought you were one. Also, both threads gave you more or less accurate answers.",
"One thing I want to add that I haven't seen mentioned yet is that most settings in Linux are stored somewhere in plain text files. This means you can modify values for things that you wouldn't normally be able to on another OS, like mouse acceleration values or the colors used in your terminal window. Additionally, you can read from those settings with relative ease, something that isn't always easy on say windows. (Try to find the path to the image that is your desktop background.) Also, check out /r/UnixPorn for some examples of people who go crazy with customization.",
"I just checked your post history. You ignore that most people there gave you good answers. Yet you crap on the whole subreddit because of a couple people that didn't. And judging by your follow-up thread, YOU are more rude than anybody on /r/linux.",
"OP, while you did get your answers, people weren't being rude to you at /r/Linux. You got all of your answers from them, yet two morons who commented bothered you. Infact people disagreed with them and agreed with you. Then you went ahead and called the community toxic and got disagreed with. You're attacking an entire subreddit over 2 redditors. That's not okay. edit: a word.",
"> I posted the same thing at r/Linux and they were so rude about it. Sounds exactly like the Linux community. Disclaimer: am part of said community. BTW I use Arch.",
"Linux is Lego. Completely customizable. Windows is a concrete building you can decorate and put furniture into.",
"I'd just like to interject for a moment. What you’re referring to as Linux, is in fact, GNU/Linux, or as I’ve recently taken to calling it, GNU plus Linux. Linux is not an operating system unto itself, but rather another free component of a fully functioning GNU system made useful by the GNU corelibs, shell utilities and vital system components comprising a full OS as defined by POSIX. Many computer users run a modified version of the GNU system every day, without realizing it. Through a peculiar turn of events, the version of GNU which is widely used today is often called “Linux”, and many of its users are not aware that it is basically the GNU system, developed by the GNU Project. There really is a Linux, and these people are using it, but it is just a part of the system they use. Linux is the kernel: the program in the system that allocates the machine’s resources to the other programs that you run. The kernel is an essential part of an operating system, but useless by itself; it can only function in the context of a complete operating system. Linux is normally used in combination with the GNU operating system: the whole system is basically GNU with Linux added, or GNU/Linux. All the so-called “Linux” distributions are really distributions of GNU/Linux.",
"> I posted the same thing at r/Linux and they were so rude about it. HAHAH. That's par for the course. Hey, I'm a life long Linux user, developer, and fan. *However,* the Linux community is full of huge assholes who discourage newcomers just trying to learn the system. It's been like this for a long time. I'll give a legitimate answer to avoid getting deleted. Linux is highly modular. It supports loading modules at runtime. It wasn't always like this, however it was still modular at the source code level. Think of a runtime module as a DLL on windows, but assume the DLL's follow a consistent interface (like COM objects.) The reason Linux is very modular is because it was forced to be. Linux developers work remotely from around the world in different timezones. Therefore, there was a strong need to separate the operating system functionality into modules so that developers could work on different parts of the OS without interferring with each other or creating dependencies upon each other. Windows had a different development situation. Most of their kernel developers were housed in the same building so they could interact in the real world in order to communicate and synchronize their work.",
"FYI, from what I've read online about similar communities, if you posted that Windows is a far superior operating system, the people over there would be more likely to (indirectly) answer your question than if you just asked. It is a shame that you had the experience you had over there, but also not uncommon (unfortunately) from what I hear. While other people have already answered your question very well, I just wanted to add that because Linux is open source, there are many different flavors of Linux. Some of these different Linux versions are bare bones where you can customize what you like, and there are others that are somewhat already setup, and anything in-between. I believe there is one that mimics windows and possibly another that is similar to Mac OS (which I believe Mac OS is based off of the Linux kernel but is different enough that Apple can still make money from it). All that being said, there are two, three or four main environments that Linux uses: KDE and Gnome and some others. These environments define what the user interface looks like and how to interact with it. This goes from creating keyboard shortcuts to installing applications. But what really makes Linux truly customizable is that it's source code is available (it is open source). Which means anyone can make even more changes than I described earlier. And if these changes are contributed to the community and enough people like it, I suppose it can eventually be utilized in a future release of the OS and probably improved upon. In fact, because of this, there are often branches of the different environment-types of Linux. This is how the multiple environments (KDE, Gnome, etc.) came about. Enough people liked each of them that instead of picking one environment, the communities kinda split up in that aspect. Sorry for the wall of text and hopefully it is accurate. I'm still a bit of a noob when it comes to Linux but I am enjoying learning more about it. I would appreciate any correction to anything that is incorrect here, so _I_ may learn more about Linux. Also, there are probably some good details on Wikipedia which, now that I mention it, I will probably go check that out again (it's been a few years since I read that page). Be fore-warned that, like anything else, that is a rabbit hole you might end up diving down when reading about this. Good luck!",
"Linux isn't even an operating system. It's just a kernel, upon which many operating systems known as Linux are built. Most of them use very similar software and incorporate different package managers or desktop environments. That's why it is so customizable, because Linux actually doesn't get you much, in the pedantic sense. You have to include all the other bits that most people consider to be operating systems. Android uses the Linux kernel, but that's about all it has in common with desktop Linux, for example.",
"Its completely open source. The source code to do whatever you want is out there and available to be modified by an end user should they want to do such a thing. If you have the source code, you can do whatever you want.",
"I followed the debacle from r/linux and basically asking a question there is against the rules( there are /r/linuxquestions and /r/linux4noobs for that). It's clearly stated on the sidebar. Additionally since linux marketshare has started going up we get a lot of trolls leaking from apple and microsoft subs so the situtation is a big tense. So I'll try to answer your question here. Linux on it's own is not an operating system. Linux is a vital part of it(the kernel) and possibly the hardest to create from scrath, but it's not enough on it's own. The kernel takes care of speaking directly to the hardware. It includes things like thread scheduler( the part that decides which application or daemon will get cpu time and when), I/O scheduler( organizing writes and reads from the hard drive), all hardware drivers and so on. You get the idea, very low level stuff. So when you say \"I use linux\" (as a desktop OS), in reality you are using linux as the kernel, plus a ton of libraries and applications on top( consisting the userland, usually the GNU userland). The result is a full operating system. An end user rarelly interfaces directly with the kernel unless it is for something technical. The main driving factor behind the customizability of linux is the fact that it's open source. Open source does not mean that someone makes some code and throws it in the wind, but rather uses a lincese that follows the code around. Linux( the kernel) uses [gplv2]( URL_0 ), while everything else in the system uses a combination of gplv2, [gplv3]( URL_2 ), or permissive like [bsd]( URL_1 ). You can read more about them, because open source has played a huge role in shaping the modern IT world and it's adoption is only expected to increase. Anyway what every single one of these licenses allows is for a user to take the source code, modify it and redistribute the modified version. This has resulted in companies and people all around the world creating and sharing software that solves all kinds of problems. This ranges from alternative schedulers in the kernel( e.g. Facebook created the BFQ scheduler for their servers and due to the fact that the kernel uses gplv2 they released it to the public), to different algorithms for thread scheduling. The result are 20 years of libre software that ranges from 20 or more different desktop environments( the graphical part of the OS with all the buttons, window management, and a software suite), multiple applications that do the same thing( e.g. nautilus, thunar, pcmanfm, midnight commander, vifm for file managers, a muriad of music applications etc). Aditionally let's say I want an application to look or behave in a specific way, but there is none that is exactly how I want it. In that case I would either make a new one( usually a lot of wasted effort), or I would take the one that is closest to how I want it, modify it to add an option to do what I want it to do and push the patch upstream( to the app maintainers). Now every user of that application will get that new option. So not only we have a lot of e.g. desktops to chose from, but we also have a ton of options on each one of them. This has resulted to the creation of modular applications that users can tweak with addons and extensions to their needs. This extends down to the more technical part of the OS, for example you can chose different file systems instead of only NTFS for windows or AFS for apple stuff depending on what you are trying to do. You can use ext4 for a stable desktop or try something more advanced like btrfs if you have a system with multiple hard drives and you care alot about data rot. Or different file system if you are running an SSD, specifically designed for SSDs instead of retrofited like NTFS( it's from Samsung, I can't recall the name). You can switch I/O schedulers depending on your workload and the type of the hard drive, you can enable/disable kconfig switches on hardware drivers and so on. At some point early on this entire ecosystem became too big to be managed by each person, so distributions were created. Each one of them is supposed to cater to a different audience with different use cases. Some of them like Debian go back to the 90s. Debian for example is aimed at users who need extreme stability and are willing to sacrifice newer versions of applications or the kernel (i.e. hardware compatibility) in exchange. It's aiming at being the universal OS, that can run on any architecture people want it to run( from x86-64 to armv7, aarch64, spark, power8/9 riscv, you name it). Ubuntu takes from Debian and tries to make it more user-friendly and ready to use out of the box with minimal tweaking. It's aimed at engineers and business users, and to some extend to the mainstream public that is not afraid to open a terminal once in a while. Linux Mint takes the Ubuntu base and narrows it down to the average Joe, making sure that everything works with a nice coherent UI and no need for a terminal. Arch Linux on the other hand is a DIY distribution that allows you to select a decent amount of the parts consisting your system on your own. It's a rolling release distro meaning it doesn't have releases, but software is updated as soon as a new version rolls out upstream. Gentoo follows the same idea but to a greater extend allowing more control but at the same time you have to compile the software yourself. Fedora lies somewhere in the middle with a stable base(desktop environment, compiler and C library version) rolling applications, while it rebases every time a new kernel is released. There are plenty of distros covering every niche of the userbase, some more professional, some more community oriented. Of course with power comes great responsibility. You do not have to tweak every single option in the system, but if you do start tweaking you have to get ready to bork it multiple times. The choice is yours. For this reason one can chose e.g. Linux Mint to just get shit done^TM or something more advanced. There is an option for everyone.",
"#I think it matters *who* you ask that question to. Imagine you have a regular guy, a chef, and a master chef. Lets say all 3 are told to make a cake. A regular guy may go to the Internet, get a recipe or suggestion for a cake he can make, and just go with it. Sure, he can put icing on it and choose what cake he wants. A chef may have experience with cakes and choose the best cake mix and ingredients to his knowledge. He makes a better cake than the regular guy cause he has experience, knowledge, and some skill. A master chef will not only know about cakes, but about base ingredients, oven capabilities, has sources to get the best stuff from and tools to outperform good chefs. A lot of Linux users tend to be chefs. Some are Master Chefs. #Knowing how to read, write, edit, and apply source code is a high end to master chef level of computer usage. A lot of people have been posting that Linux is \"open source\" and that every piece of it can be scrutinized and reviewed. That's like a regular guy inspecting every chicken that laid an egg for the cake, the health of the wheat grown for flour, the quality of the sugar that goes into the cake, the strength for the vanilla extract, etc. It's impossible for the layman to inspect everything on such a small level. We entrust people who specialize in certain fields to test and review each ingredient instead. #Linux is only superior to people who have the ability to manipulate it on a skillful level. Otherwise, it's pretty much like Windows, Mac, Andriod, or 3rd party proprietary on a simple level. Honestly, I wouldn't worry about people gloating that Linux is so and so. There is a sharp learning curve and a horrible level of accessibility for 3rd party products for it. Most people brag about Linux doing 1 or 2 things well like serving data. No one brags about Linux's odd lack of support for off the shelf products or it's obscure methods of management.",
"So I think to really answer this question, you have to understand what exactly computer programs are. I'm sure you're familiar with the term computer processor. On a physical level, a computer processor is composed of silicon with dopants such as phosphorous and nitrogen such that electrons and so electricity behave a certain in a well-defined fashion - the arrangement of dopants and silicon is called an electrical circuit. These circuits can do things like hold high voltage states and low voltage states, read high voltage and low voltage states and then produce other arrangements of voltage states. It doesn't have to always have to do with high and low voltage states, but much of our modern electronics involve high and low voltage states - this high and low and nothing in between is what \"digital\" refers to; as opposed to \"analog\", which is when all the states in between are also used. So the processor holds a bunch of these electrical circuits in its silicon. Certain circuits can hold collections of high and low voltage states. If we think of high voltage as representing 1 and low voltage as representing 0, we can start seeing collections of high and low voltage states as base 2 - or binary - numbers. The term used to described the information contained by just one of these high / low voltage states is \"bit\". You may have heard of this in terms of \"32-bit operating system\" or \"64-bit operating system\". This means that the default size of information used by the operating system for certain operations are 32 of these states together, or 64 of these states together. A processor also has other circuits which can take these collections of high and low voltage states in one area of the processor and produce new high and low voltage states in the same or other areas of the processor. If we see the high and low voltage states as bits which represent numbers, these circuits perform functions such as adding together numbers or other arithmetic, as well as other operations such as reading the information contained in a certain area of the processor. The functions a processor can do is called an instruction set. The processor keeps track of what instructions it can perform by having an associated number called an opcode. For example, I could say instruction #12 is adding this and that number, instruction number #55 is stopping an operation. At the most basic level, a computer program is a list of these instructions - this is called the machine code or machine language. Of course, when we think of a computer program it might be more like this: def hello_world(): print(\"Hello world!\") instead of something like this (note, opcodes are often represented in base 16 - or hexadecimal): B9 3A A8 FF DD 84 The program we saw at the top, with words we understand - that program gets turned into something like the machine language below through something called compilation. Compilation is done by a compiler, which is a computer program which can translate some human-readable input into the machine code which the computer can understand. This may seem like a chicken-or-the-egg problem - how was the first compiler written? The first compilers were written by humans in machine code. The compiler is the basis of any programming language - such as Java or Go or Rust or Haskell or Swift or C or C++ or so on... Since a given processor might have a different instruction set from another processor, a compiler needs to be specific for a processor's architecture - so there's language-specific compilers for x86-64, or ARMv7, or MIPS, or PowerPC. A compiled machine language program for one processor architecture will almost certainly not work on another processor architecture. Also, when a program gets compiled a bunch of the human-readable information that helps a lot in understanding how the program works is lost. It is not easy to take a compiled program then \"reverse-compile\" it and try to understand what comes out. So here's the thing - the compiler takes the human-readable code in whatever language and spits out machine language. After you get that machine language program for your specific processor architecture, do you need that human-readable code to run that program? The answer is no. That compiled machine language program the only thing given in closed source products. Linux is open source - they make its human-readable code freely available for everybody to use. That means that if you want, you can take the Linux code and modify it then recompile it and get your own personal version of Linux. Meanwhile, for closed source software like Windows and Mac OS, you aren't going to get the source code and so making modifications are pretty much impossible or at least involves dealing with cryptic code derived from machine language that's extremely difficult to read and may only be relevant and true for whatever processor architecture you have. Meanwhile, the modifications you make to Linux can be shared with people with other processor architectures by recompiling the changes you made using compilers for different instruction sets.",
"Most OS is like buying a house. When many people have a house, they want to live there, not knock down walls, try a different wall, or make an interior wall a fish tank. Linux builds let you break, fix, and seek answers to problems that aren't quite so encouraged in other places.",
"First off, I'm sorry people over at /r/Linux were rude. Pretend you'd like to change a meal you eat every day. Microsoft and Apple don't share their recipes, they want to keep it secret, and you have to buy the meal as is without knowing how its made from the store pre-packaged and you just have to eat it the way it is. Linux comes along and not only shows you the entire recipe, how its made, but gives it away for free, with so many options its a bit annoying. That's the simplest explanation I can think of.",
"Sorry for the poor reception. Many of the Linux peeps forget that we all started on equal footing. Don't let the snobs tarnish the entire community. Linux is a great OS and if you have the time and desire it can be exactly what you want!",
"Easiest way to explain the concept is to ask: Why is making your own food more customisable than buying ready-made from the store? The answer is of course because when you can get your hands on the ingredients you have more control, and thus can change anything you like. Note that this might not necessarily make things better, will take more effort and you might not understand or want to understand what you are doing, but you have that control. Linux 'distros' are a bit like those companies that sell you a recipe and all the ingredients to make it with instructions. They have already done some of the work and come up with a good recipe and you can use that as a starting point, but you could still change things if you wanted and knew how. Now the real question is how important is this to you.",
"To do a ELI5 explanation: Imagine you want to buy a car. You can go to a dealer, and buy a well tuned car which was built and tested in a factory by the manufacturer. That would be your Window or Mac OS. Now, there's another possibility. You can go on internet and download the blueprints for a car. You have the choice to put an engine and customize it for speed, or for less noise. Then you have the option to put on top different gear boxes. Then you can choose what frame you want. And what kind of buttons to have on your steering wheel. Depending on what you want, you can end up with a race rocket or an off-road monster BUT, ... you have to do the work. In the end, Linux was thought more like a blueprint, while Mac/Windows is sold like a finished product.",
"Since your question has already been aptly answered by /u/JaceTheSaltSculptor I'll just take a moment to apologise on behalf of the Linux community for the bad experience you had at /r/linux. I've been running Linux as my daily operating system both at home and at work for a few years now and naturally still find myself asking stupid questions in forums like /r/linux. One of the cornerstones of Linux's massive success is the active collaboration among all of its contributors and the fact that someone shows interest in it and is treated disrespectfully is very damaging to our community. Unfortunately, as with everything in life, there are jerks everywhere, and Linux is no exception. For anyone who's not particularly tech savvy, Linux as an ecosystem is already pretty hostile as it is, so if you have to factor in people's sarcastic replies when asking for help, it's only normal people decide it's not worth their time. Even though the general sentiment of the Linux community towards newcomers is not bad, when someone new to Linux is received with negativity, they have yet another reason to think Linux is hard, painful and only ever used by a bunch of insecure, elitist neckbeards. Please don't let that experience drive you into thinking the whole Linux community is that way, because it definitely isn't.",
"As others have said Linux is kernal (core of the OS). On top of that is a very modular design. Various people have built different moduals that go on top of the kernal them. Now in Windows you install different programs on top of the OS, but they all have to talk to the kernal and hardware through the OS. But Linux based operating system can have the various parts of of the OS traded out as the user pleases, and many can be removed. (You still install programs as well, but basically the whole OS in smaller programs you can trade out) Installing a Linux distro on low powered laptop? Pick a distro built for that or assemble your own (if you want to). More powerful desktop, install a Linux OS that has more features, but requires more power. Can't find what you want? Grab something like Arch Linux and install just what you want. You can see this with how Android (A Linux based OS) changed from different phone manufacturer. The GUI aka the skin your phone runs changed from manufacturer to manufacturer. Google's Nexus and Pixel lines run what some refer to as \"stock Android\" while Samsung used their Touch wiz interface. But these can be somewhat changed thanks to Linux's flexibility, allowing you install different launchers to changed you \"desktop\" on your phone. All thanks to Linux's flexibility. Down side to all this is Linux doesn't hold your hand like Windows, and worse Mac, does. With Linus you can completely wide your system accidentally with s few lines in the command prompt. It's kinda like the difference between my 2014 truck and my friends 98 Wrangler. The Jeep you can drive around with no top, no doors, no window, etc and the vehicle doesn't care. If I foget my seatbelt my truck won't shut up. Truck is Windows, Jeep is Linux. Linux says do what you want, just don't come whining to me if you bork your system.",
"Let's pretend you're buying a new car. First you go at the typical Microsoft car store. Their Windows model is popular; the car it has nice leather seats but a trashy wheel. When you ask the vendor if you can replace the wheel, he says \"no... our product is sold and used as a single piece. You won't find another suitable wheel anyway.\" The fancy Apple car store sells OS X models. They're flashy, but same deal as above: you aren't supposed to replace parts you dislike. Then you go to the bazaar where the Linux and BSD crowd sells cars. There are a thousand vendors, each yelling \"CHECK OUR CARS, MADE FROM THE FINEST PARTS!\": Canonical with their Ubuntu, Red Hat with their CentOS, the Debian Foundation... there's even a guy selling \"how to build your own car from scratch\" manuals! But when you check the cars, some models have some identical parts, and some different parts. It looks like there are two motor in all models (with Torvald's motor being the most popular), three different starters, five or six different bodyworks, ten different window models... all of those in almost infinite combinations. Heck, there's even a guy who decided to sell cars with pink rocket launchers! (There are also the ones who copied the model from someone else and did a paintjob.) When you ask one of the vendors on why this happens, he says: \"it's normal here. We rarely make the parts, we buy them elsewhere. Each vendor picks the ones they like the most, depending on what the car is supposed to do, then assemble the model at home and produce the cars we sell. And of course, if you dislike some part of my model, you can replace them at home, I'll give you a list of part sellers.\" ________________ *This* is the reason Linux is more customizable than most other systems. They're made as single pieces, while Linux is actually a bunch of spare programs made to be used together - and made to be *replaced* if that's what you want. The *Linux distributions* (Ubuntu, Mint, Fedora, Suse...) you see out there are like those car models on the bazaar - pre-made with certain programs instead of others, but nothing prevents you from picking new programs and switching them. For all intents and purposes, you can replace anything in a Linux distribution with an alternative. Not just your browser or office suite; you can do it with the initialization (the \"starter\"), the desktop environment (the \"bodywork\")... you can even take Linux (the \"motor\" = kernel) out of a Linux distribution, replace it with something else and get an usable system, if that's what you want! And if starting from a distribution like this feels like insufficient, you can also start from scratch. Grab a Linux from Scratch manual and literally build the system from some programs you download."
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728mhm | What makes Windows have the best gaming support, when Macs and Linuxes do not? | Technology | explainlikeimfive | {
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"I'd say DirectX inertia. DirectX as often opposed to OpenGl, is a set of high level libraries to make games (such as Direct3D or DirectInput, respetively, allow for 3D computing and controller management). It is unfortunately only available on windows. But opengl is as performant as DirectX is.",
"Windows is the computer operating system with the larges installation base so it is naturally that games are primary developed for windows and mac, linux in second case. The support for games are good on all platforms. If they are available the are often identical. Look for example on steam for mac and linux games",
"In the case of Mac, it goes way way back to the mid-1980s. Before Windows, Before DirectX, before even Steve Jobs got fired. The Apple II, while expensive, did have a very respectable game library, as well as strong developer support. Home computers were still largely a curiosity though. The real money was in enterprise, which IBM was dominating with their PC line. Despite Apple's \"fun\" reputation today, the Macintosh was originally geared to be more of a workstation. Corporate clients didn't want gaming capable computers, as games were seen as a potential productivity leach. To combat IBM, Apple strongly discouraged game development for the Macintosh platform, instead focusing heavily on software for businesses and creative professionals. The Macintosh was perfectly capable of playing games, but there was just no support for developers. Game development continued for the Apple II throughout the 80s, but comparatively few games were released for the Mac. The bulk of which being edutainment titles. Now the PC, the PC was modular, unlike the Mac. So while it didn't ship with gaming in mind, it could easily be upgraded into a gaming system. MS-DOS was also well understood by developers as well as users, where as MacOS was brand new, and as I mentioned, Apple had little in the way of game development support. PC gaming had a slow burn at the start, but the release of the AdLib and the VGA cards in the closing years of the 1980s really accelerated it as a major gaming platform. Which only picked up stream with important releases like Wolfenstein, Doom, and Quake in the 90s. Through the 90s, Macs did start seeing improved game support. Especially through the PowerPC years. Pretty much every major PC release did see a MacOS port. It even saw its own major exclusive, Bungie's Marathon series, the spiritual predecessor to Halo. Releases were still few and far between though. By this point, Apple had solidified themselves as a productivity focused brand. Which continues right up to this day. Apple has never released a gaming focused Mac. Instead the company has chosen to focus their resources on mobile gaming, with the iPhone long being the best supported and most powerful mobile gaming platform. As for Linux, it's user base is too small and fragmented to make gaming really viable. It's also primarily used for productivity and embedded systems. While gaming is not common on desktops, Linux has seen strong gaming support on mobile devices. Android runs on the Linux Kernel after all. The PS4 also runs on the BSD kernel, which is a (very) distant cousin of Linux (they're both Unix-like). Mac OS X and iOS are also BSD based. So it's not that these operating systems can't game, and they do if there's a large enough market."
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729vfv | How are television shows/radio programs chosen? | I know I sound dumb, but is there someone working at the company of the broadcasters in front of a big control panel choosing what to air for which time? Or is it a playlist auto generated? | Technology | explainlikeimfive | {
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"Its extremely planned out, you have entire teams of people doing this in their scheduling department. There's a lot of research, analysis and data that goes into exactly what to put into each time slot. It is not haphazard at all, very detailed planning"
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72a7hf | what are the tripod camera things used by construction workers on street corners in cities and what is their purpose? | Technology | explainlikeimfive | {
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"Survey equipment. They can either be line of sight or GPS. The GPS systems work kind of like you think. They set a control point that is known and then will take a separate piece that will tell them the position and elevation in relation to the control. Line of sight systems have a viewer that you use to look toward where you want to measure and another surveyor will have a pole with a reflector on it that will allow a distance measurement. I know this is a simple explanation and I hope someone else with more drive than me explains it better.",
"Those are tools to precisely measure position. There are actually several devices that can be mounted on tripods for this purpose. The camera looking ones are either a sight or a reflector to precisely measure distance and angle. If you see things that look like they have a UFO on top, those are high precision GPS devices to get point locations."
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72av5j | Why do 'bionic' hands/arms have such stilted and unrealistic animations, when this creepy robot puppet can have such natural fluid motion? | Compare [this dancing...thing]( URL_0 ), to what is apparently humanity's best attempt at creating a natural looking and functional [prosthetic limb]( URL_1 ). I get that the limb has to be functional (able to grip and hold objects without crushing or dropping them) and that the puppet is probably a very lightweight material such as styrofoam, but it seems like the servos powering the bionic limb should be able to be programmed with the same sort of inverse/forward(?) kinematic animations. Perhaps the puppet is using some sort of string/ligament system instead, perhaps giving it the naturalistic movement, but then why can't a functional limb be built around this system? What limitations are preventing such a realistic looking arm (at least in terms of behaviour) and is anybody actively trying to overcome these limitations? | Technology | explainlikeimfive | {
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"The robots movements are all computer controlled and preprogrammed. A limb is controlled by the user and has to make 100's of varying movements on the fly in real time, its the human/limb interface thats the problem, and yes alot of money is being poured into it. Just look at military research.",
"You effectively answered your own question - current development of artificial limbs is still mainly focused on making them functional, rather than addressing mostly asthetic issues such making their movement \"smooth\" or \"natural looking.\"",
"Cost is a factor too. The programming and engineering needed for making something functional and practical is one cost. Then there’s the programming and engineering needed to make it realistic and fluid, that would tack on the cost for people who need the limbs. There’s also the likelihood that you will sacrifice the former when including the latter. And people who need arms or hands would be better off with functionality than fluidity."
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72comc | How do headphones go through my washer machine and dryer and still work? | Technology | explainlikeimfive | {
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"Generally speaking, water itself doesn't damage electronics. Issues come into play when water itself or minerals in water create new electrical pathways, creating a new, higher-voltage pathway to sensitive components that can't handle it. That's why the whole \"turn off your phone and put it in a bag of rice\" for a week thing works - you remove power from the device, then leave it sit until it's COMPLETELY DRY. As far as headphones go... 1. Headphones are very low power 2. Headphones are incredibly simple and there aren't really any sensitive components."
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72djii | How is the code written for something like a calculator or a digital watch? | Technology | explainlikeimfive | {
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"If you want to skim what building the code looks like, here's the links to a two part tutorial on a simple calculator program (including window and user interface) [Part 1 ~14 minutes]( URL_1 ) [Part 2 ~ 14 minutes]( URL_0 ) There is a lot of background work done on the programming languages. For example, the tutorials above are written in Java. When using a language there are a plethora of built in tools ready for you to use. Even basic things, like the definition of multiplication (coded like 2*2 would produce 4). This \" * \" is predefined by java as multiplication so you can make (a * b = answer). The language lets you say \"button press 1\" * \"button press 2\" is multiplication. The buttons and windows are all built in as well, you just need to know a few lines of code for how to plop one down and adjust its size and position. For watches I am far from knowledgeable at all (assuming the above calculator description will suffice with my basic knowledge of code). If I remember correctly, watches use a tiny quartz crystal that a battery sends a current through. This quartz vibrates at a constant frequency, meaning it vibrates an exact number of times every second. (From here I am making a logical assumption) They must have a small piece of hardware that counts these oscillations, and when it senses one, the count gets increased by 1 (code would be something like \"count = count +1\" meaning add one to the current count). When it hits its peak, probably somewhere around 30,000 (meaning quartz will vibrate ~30,000 times a second, again my estimate) it will add 1 to a second counter and reset the count of vibrations. Code would be something like (this is not code that will run, just something similar looking/conceptual): count = 0 if (vibration is felt) //A lot of code props for sensing a vibration and recording it count = count +1 if (count = 30,000) count = 0 //When you hit the number that signals 1 second, reset the count and start over seconds = seconds + 1 //Add a second if (seconds = 60) //60 seconds = 1 minute seconds = 0 //A watch will only count 60 seconds minutes = minutes +1 //At 60 seconds, add a minute if (minutes = 60) //60 minutes make an hour minutes = 0 //At 1 hour, reset thh minutes to 0 hours = hours +1 //At 60 minutes, add 1 hour if (hours > 12) hours = 1 (this line is for non military time, and would set clock to 1 after 12 oclock, and run through all numbers until it hits 12 again and goes back to 1)",
"Pretty much like any other device. The CPU has a specific instruction set, and the code is embedded in a ROM that the device runs."
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72dmg1 | Why do studios go after people who download their content? Wouldn't it make more sense to go after the uploaders? | Especially since there's way fewer uploaders to deal with than downloaders. | Technology | explainlikeimfive | {
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"* the originally uploaders are difficult to find, and are often operating in a jurisdiction where it is hard to get at them * bittorrents are one of the most common way to transfer copyrighted content, and the way that the technology works, most people are both uploaders and downloaders",
"They do primarily target the uploader. You will rarely ever see them go after downloaders and they only do so for the most severe offenders.",
"they do. but uploaders are harder to go after, they are more savy and cover their tracks. good chance they arent even in the US.",
"They do target uploaders and upload host services when possible, but many of the popular ones are hosted overseas and beyond their legal reach. Some nations have weak or nonexistent copyright protections, and uploaders in those places may not even be breaking a law."
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72edgo | How do Fitbits count the steps? | Technology | explainlikeimfive | {
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"Fitbits have a small accelerometer inside. This is a piece of hardware that can detect changes in velocity, in both intesity and direction. Your smartphone has one inside too, albeit maybe not as sensitive. Software tells the accelerometer what a step \"feels\" like compared to other random motions. You can even teach the fitbit what your paticular step or gait is so that it can be more precise."
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72f57i | Why does leaving your phone on a charger overnight degrade the battery? | Technology | explainlikeimfive | {
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"It really doesn't. The trouble with battery advice is that people keep repeating stuff that was written for entirely different battery types several decades ago. Sometimes they even refer to the \"memory effect\", which is something that which only applied to NiCD (a battery type that's been almost completely extinct for more than a decade and isn't used in phones or laptops), a very particular type of them at that (so not nearly all of them), and required such a regular usage pattern to reproduce that it's not seen outside of laboratories and satellites. Yeah, overcharging batteries is bad. But given that lithium tends to explode or light itself on fire when abused, and that it costs companies big $$$ and it makes the news when anything of the sort happens... a bad lithium charger is pretty much nonexistent outside of really cheap junk from China.",
"I didn't read the article but this is basically how it works: Phones have chips in them that detect the power being put into the battery and regulate it. When the phone detects the battery is full and that there is still a charger connected, it kind of turns the battery off. Instead it just powers itself directly and skips the battery. Overnight charge degradation hasn't been a thing for a long time.",
"And wow the contradictions here are many and frequent. How is anyone to find out what is the right way and wrong way to charge your phone/tablet from these comments ?",
"Op did you even read the article you posted?"
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72fn1k | Why does my iPhone jump from 15% to close to 40% almost immediately upon plugging it in to charge? | Technology | explainlikeimfive | {
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"Phones don't actually know how much % is left until the battery is drained; they only know what the full charge voltage is, and what the empty voltage is. When you plug in your phone, especially if the battery is older, it will sense a huge jump/loss due to the influx of power. You really aren't getting 25% of your charge instantly, just a measurement quirk."
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72fnfq | why are old computers better than new in space? | I've heard from a friend of mine that the computers that are used in space are old and slower. Can someone please explain why would older and slower be better and why not make computers with the technology we have today but adapt them to space I guess. I have no idea whats going on here so please, any article or simple explanation would help because I can't see a reason that older technology is actually better. Maybe I am not thinking enough outside the box. Thanks | Technology | explainlikeimfive | {
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"NASA uses older computers because they're reliable and reliability is more important in space than computing power. A computer in a spaceship has to deal with a lot of things that your desktop doesn't. Intense vibrations from the take off can damage a processor and high-energy rays in space can even alter computer memory, which can cause a fatal error. Additionally, failure on a spaceship or satellite potentially means lost lives or hundreds of millions of dollars lost on a failed mission. Failure on a desktop usually results in you have to load your last save from ten minutes ago. Finally, NASA doesn't need to have supercomputers on board its spaceships and satellites. The computers in the actual vehicles just need to be capable of controlling the systems on board, dealing with navigation, etc. Any data crunching or complex equation solving can be done on supercomputers on earth using information sent back by the spaceship.",
"It isn't so much that they're better, it's that they've already been tested and shown to work. Certifying anything for use in space is incredibly expensive and time consuming, and the astronauts aren't trying to play Destiny 2 or stream 4k moves. Older, well tested computer systems perform fine for their needs. So that's what they use.",
"There will be two different types of computers in space. Laptops used by astronaut in space and computers use in spacecrafts etc For laptops is it quite new hardware and in a [article]( URL_1 ) from 2014 the most of the was Lenovo T61P released in 2007 The all used Linux with special programs for all control. A older computer is not necessary better but a computer but the computes has to be tested for radiation testing, off-gas testing, thermal testing, fire & fire suppression among other thing so when one modell is testes is a smart idea to by a bunch for the and use them for a while. There is 80 laptops on ISS so having as few models as possible is a god idea because testing is expensive. They likely have a small supply of replacement parts if there is anything broken so few models is a good idea. The space station provide shielding for the computers and they are not mission critical. They are used for interface to the space station but there is other computer in it that controls the station and they can be replaced if the fail. Computers in satellites, spacecraft, probes is another story. The have to work without replacement for the whole mission. A unrecoverable error might destroy the whole mission that might cost billion of dollars Radiation is space is a bit problem, it can change bits in the CPU and result in incorrect result . So the electronics has to be (radiation harden)[ URL_0 ]. The manufacturing process i modified and optimized to survive radiation and the design is do so that radiation induced errors can be corrected or if not corrected the will be detected. The modified manufacturing and the design will result in lower performance then commercial processors. Spacecrafts takes years to design and test so the processors has to be available when the spacecraft is designs and that is a couple of years before launch. The market for radiation harden processor is limited. The market for a CPU might be a couple of hundred versus a couple of million for a CPU used in product on earth. So they are expensive because the R & D has to be spread out on a few so you done develop new modells at the same rate as CPUs for ground use."
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72fsyk | How are downloads and storage mediums so accurate, such as keeping billions of bytes without a shred of noticeable corruption? | I am fascinated by Hard drives, and how it seems most people take them for granted. I have had a 1 terabyte Hard drive, and I have had it filled with games for about 3 years, and none have corrupted or needed to verify the game files. My other question is how do downloads stay so accurate, as I thought while downloading a 200 GB file, with zero corruption? It dosent seem like it verifies the content after it downloads, so how do they avoid corrupt downloads? | Technology | explainlikeimfive | {
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"The drives themselves have on-board error checking that can remap bad spots out of \"spare\" space on the drive. Your 200GB drive may actually have about 205GB space on it, but that other 5G is reserved for remapping those kind of bad spots (those numbers may not be exactly accurate, just an estimate). The network transport protocols used to move the data between servers also have error detection and correction in them. Your game download is made up of billions and billions of data packets getting transported to your computer. Every one of those data packets is checked for an error via a checksum. If the checksum fails, then the packet is flagged as bad, discarded, and your network card asks for a retry. And finally, when you install your game, the installer itself verifies the integrity of the files you've downloaded via a hash or checksum. This allows you to verify the file wasn't corrupted *and* sometimes it's validated against a cryptographically signed hash to verify that it wasn't tampered with somewhere between point A & B.",
"There are two aspects to this question - how do we verify the integrity of a set of data, and how do we correct the data if we find corrupted bits? Data integrity is attacked by random corruption all the time, both on transmission and in storage (cosmic ray bit flips, random internet packet shenanigans), but integrity checks (parity bits, checksums, redundancy checks) allow for fast identification of corrupted data. Network protocols like TCP/IP allow for automatic re-request of data that's found to be unworkable, while parity files (basically keeping spares) can help restore files if something happens while on disk. When you see that the OS is reporting corrupted files and telling you about it, it means that all of these checks and automatic correction mechanisms *failed*, and that happens in a personal computer once in a blue moon. Happens pretty regularly in high load servers, which is why RAID striped storage is used to help combat it further."
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72gdvn | how do surgeons keep your eye from moving during eye surgery? | Technology | explainlikeimfive | {
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"So I have had several different kinds of eye surgeries, and I can tell you what they did in each instance to prevent eye movement. So for lasik, they give you numbing drops and cover the eye that is not being worked on. Even with the drops, you still have full control of your eye movement, the drops are for the pain. Then they have you focus on some kind of red dot/ light while they work on your eye. Focusing on that helps you not move your eye so much. Of course, your eye still might move, so the laser they use tracks your eye movement and stops when necessary. For the cryo- laser surgery I had on my retina, they gave me numbing drops and a local anaesthetic. Yes, it is what you're thinking. They stuck a needle in my eyeball to numb it. It was terrifying and incredibly uncomfortable. The needle went in through my lower eyelid and into the center of my actual eyeball. Once the anaesthesia took effect, I could not control the movement of that eye, so the doctor was able to move it around with what I think was a cotton swab to get it in the position he needed it. No worries about my eye moving when it shouldn't, because I had zero control over it. Weirdest. Feeling. Ever. Kinda like when they numb your mouth at the dentist, except it's your fucking eyeball. My second and most invasive surgery for my retina, I was given general anesthesia, so I was completely out. No worries about eye movement in this case. Hope this is helpful!",
"when I had LASIK (about 15 years ago) my surgeon told me that his only real job was to keep my head steady during the procedure. On top of that, the machine can detect movement and adjust, and will stop if you move too much. And the actual process is only a few seconds. I remember staring at the red dot and being terrified of moving my eyes. But it happens so fast you don't have a chance to move that much. They gave me numbing drops but nothing too dramatic. I imagine with cataract surgery they actually use drops that will paralyze the eye muscles.",
"So during cataract surgery most people are given just numbing eye drops to prevent pain but nothing is actually given to prevent you from looking around. However, one can't see much while the strong light of the microscope is shining during surgery, so most people are able to to stay still for the short period without too much difficulty. In order to actually prevent the eye from moving an anesthetic injection can be given which temporarily paralyzes the eye muscles. This is commonly used in longer and more invasive eye procedures such as retinal surgery."
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72j0wi | How does programming work on hardware? | I mean, all the programming I've done so far is in java and C#, but how do they make all those words that i write, be understood by the hardware? | Technology | explainlikeimfive | {
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"**In short:** The compiler does that for you. It translates your words -- which already follow certain rules to be understood by your compiler -- into something the underlying hardware can understand. **A bit less shorter:** Your source code usually gets preprocessed into a modified source code. That modified sourcecode already contains a few \"machinizations\" (just some simplifications towards the machine and compile process). A compiler creates a assembly language code (so going from a high level language to a assembly language such as x86 ASM). On that level you see operations based on registers instead of variables and objects. The assembly language code gets \"assembly'd\" into a machine code (decoded 'readable' assembly into unreadable sequences of numbers). The machine code still needs to be arranged and linked with the libraries you use. That gets done by a linker and loader (in C# you sometimes you dll's which basically correspond to that). The linker and loader takes care of putting the arrangeable machine code into the proper order for the underlying machine. The end result will be the machine code in the pure machine language consisting of the number sequences which the processor reads from a memory byte by byte (sometimes two bytes or more but thats a different topic). **A side note:** I talked about compiler languages (quite generally) here. There also exist pure interpreter languages like Python or some mixed languages like Java. Those work a bit different but the underlying principle uses similar techniques on the machine level. For interpreter languages we have a interpreter which literally interprets your source code line by line and executes system level operations straight away. This requires these operations to be written and complied once to be available on the interpreter language. So the magic is hidden there. Java on the other hand -- in my opinion -- works in the inbetween way with some additional perks. We have our source code which gets compiled from a .java file into a .class file. This class-File is the java Code compiled into a assembly language like on x86 _but_ for the Java-Virtual-Machine (jvm). It contains a general set of operations which are available on pretty much any machine. The jvm on the other hand has to be created for every architecture itself. So you have a jvm for x86, one for ARM, one for amd64, ... The jvm interpret the Java ASM into machine code instructions straight away for the processor to be interpreted. For further reading I recommend books on computer architecture from Hennessy+Patterson or Tanenbaum (well when it comes to computer engineering/ comp sci that Tanenbaum guy shows up everywhere i think... he is great :) ). Also books on operating systems give insight on how the layer between the user and the processor work. Specifically about this topic i wrote about? The author of Compilers: Principles, Techniques, and Tools (Aho, et al) dive very very deep into this topic. I'd not require it but I name it because its the book which covers this topic the most. The others i mentioned are standard books on the topics i mentioned. **EDIT:** Formatting and words. -- Also my side note is longer than my actual post lol **Second side note:** Every compiler goes to similar phases I could also talk about which are very interesting. But as mentioned Aho et al goes deeper on this topic ;)",
"Compilers, they turn whatever code you wrote into actual binary code (most of the time) which your computer can execute."
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72kc2r | US congressional budget reconciliation. Why does it exist? Why is there a deadline? Why does it mean one party needs fewer votes? | Technology | explainlikeimfive | {
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"The budget reconciliation process was created by the Congressional Budget and Impoundment Control Act of 1974. The idea behind it was that small changes could be made to the budget to cover things that were unforeseen when the budget was passed without having to go through the process of creating a new budget. The key limit was that all changes had to be revenue neutral, so that the end amount in the budget that was approved by vote wasn't changed. Since this isn't a new piece of legislation, but a procedural change, it cannot be filibustered in the Senate. That's why you need only 51 votes. The deadline is the end of the last budget that was voted into law. If that budget is over with, you can't just make changes to it, a new budget has to be created that goes through the formal process.",
"1. The US Constitution gives each chamber of Congress essentially unilateral and unchecked authority in determining its own procedural rules. In effect, though no bill may be presented to the President unless it has been passed by both chambers, each chamber gets to decide for itself what the process is going to be from a bill first being introduced until it gets \"passed\" (or not). 2. The US Constitution requires all tax bills originate in the House. Budget bills tend to involve both taxes and spending, so for all practical purposes, they have to originate in the House. 3. Once the House passes a bill--however its procedures indicate that happens--it goes to the Senate. The Senate can then do one of four things: nothing, vote it down, approve it as-is, or approve it with amendments. 4. If the Senate nothing or votes the bill down, that's the end of it. If it approves the bill as-is, it goes to the President's desk for approval. But if it amends the bill. . . then the same bill hasn't been passed by both chambers. It's only if the *same* bill has been passed by both chambers that it can be presented to the President. So if the Senate amends, the House has to take another crack at passing the bill, as amended, before it can become law. 5. But at that point, there's no reason the House can't treat it like any other bill it's received from the Senate. Meaning that just like the Senate amended the original House bill, now the House can amend the Senate's amended bill. 6. If the House does vote to amend the amended bill, *that* bill then goes back over to the Senate, which can amend *that* version. . . . and round and round and round she goes. You see how something as massive and potentially controversial as a federal budget bill might be incredibly difficult to get passed at *all* under those procedures. Each amendment by one chamber gives the other chamber an opportunity to amend again. Things would be bad enough if the House and Senate were controlled by opposing parties. But even if they were controlled by the same party, political differences between the chambers would crop up with some regularity. And that's to say nothing of the fact that the minority party could very easily make use of all these opportunities to offer and force votes on amendments to prevent a budget from ever being passed. The \"reconciliation\" process permits that process to be short-circuited for certain bills. The specifics are pretty arcane, but the ELI5 version boils down to this: once both chambers have passed *some* version of a budget bill, they work together to create a \"reconciled\" version that can be passed--without further amendment!--by each chamber on a straight majority vote. That not only puts a stop to the unending amendment process described above, but also makes the reconciled bill immune to a filibuster in the Senate (i.e., an equally arcane procedural quirk which permits any member of the Senate to prevent a bill from even coming to a vote unless 60 Senators vote to end debate, which in today's political climate is pretty tough).",
"The Senate has a rule that a bill cannot be voted upon until debate is finished. This is not a constitutional requirement or anything, just a rule that they have agreed to be bound by. So senators can prevent a bill coming to a vote by continuing to talk until the clock runs out - called a filibuster. The vote to tell the senator to stop requires 60 votes. The minority party, currently the dems, are going to filibuster any bill that they oppose and the GOP doesn't have the votes to defeat it. Reconciliation is a bit of a loophole in that they can pass budget items with a simple majority, provided it is revenue neutral. So they have to engage in all manner of accounting tricks to make bills appear revenue neutral in order to pass muster under this rule. All of this is moot if the Senate scraps the filibuster rule, which both sides have done or threatened, but it would mark a dramatic change in Senate procedure and few are willing to risk giving the other party that power."
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72lpg5 | why do touch screens fuck up in the rain? | Technology | explainlikeimfive | {
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"They sense the presence of something touching the front of the screen that effects electric charge. The tip of your finger does this, but so do raindrops.",
"Also fun fact: If absolutely pure water was on your screen, it probably wouldnt cause much of an issue. Water in its pure form is not a very good conductor. It is because of dissolved solutes in the water that it is conductive enough to mess with the screen. I keep saltwater aquariums and saltwater of the screen completely fucks up the screen.",
"Touch screens working through things that conduct electricity, like fingers, but also water",
"Most modern touchscreens are capacitive. So you've got two conductors separated by an insulator. When you apply a charge to one of the conductors, the opposite charge manifests on the other conductor. Your finger carries with it a low level of charge, so it can be used to create this effect. However, it is a very fine effect that is dependent on the conductor near the surface of the screen be surrounded by free space. When you get the screen wet, you disrupt the effect and cause it to dissipate the charge somewhat. This is often enough to throw the resulting charge on the other capacitor out of the range it views as an actual touch."
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72nzfr | How does a cotton candy machine even work? | Technology | explainlikeimfive | {
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"A cotton candy machine melts sugar into a liquid and then sprays it out of a tiny nozzle. As it is exposed to air it cools and solidifies into incredibly thin threads of sugar which are built up into a fluffy mass. Dye is added so the threads aren't just white but it would work just fine without the color."
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72qyp4 | How exactly is the meat industry causing so much pollution? | I'm always reading about how the meat industry is the worst contributor to global warning. What is it about the industry that makes it so damaging to the environment? | Technology | explainlikeimfive | {
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"As with anything it depends. The easiest to point a finger at is the beef cattle industry so I'll take a whack at that. Three main reasons: farts, inefficiency, and erosion/runoff. Cows have a sequenced digestive process and they give off a lot of methane. Methane is a greenhouse gas that is much stronger at causing the greenhouse effect than carbon dioxide which is what most people worry about (think of car pollution and planting trees for carbon offsets) The meat industry is inefficient with how animals are fed. In terms of resources used to make a single serving, beef has some of the most resources for the smallest amount. This is particularly true for water. Fresh water resources are a difficult thing to manage and meat industries use an incredible amount of water all the way from watering feed crops/pastures to keeping the animals themselves hydrated. Another big issue is erosion and runoff caused by cattle farming. These are mainly a result of how, being an industry, you have areas where there are many hundreds or even thousands of cattle near each other. The sheer physical presence of so many cows causes the landscape to change. Often they will be near a stream or river (because they need water to drink and irrigate their pastures). The change in landscape from so many cows ends up damaging the waterways so much that it is often unable to ever repair itself. Also all the urine from cattle (not to forget any fertilizer used by the farmer) causes anything downstream that isn't destroyed to be contaminated. I strayed and talked more about environmental impact and not just pollution but people often use the two terms interchangeably. If you mean just air pollution then it is the first point I made plus diesel transport trucks and the desire of people wanting meat all times of the year making it a continuous process instead of seasonal to give Mother Nature a break. On mobile but studied this kind of thing ;)",
"Cattle being bred for meat eat and fart and poop. That's a lot of fart and poop. The gases get released into the atmosphere and add to the greenhouse gases."
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72rtpb | Why do electronic items (like headphones or laptops) slowly lose their charge when they're not being used? | Technology | explainlikeimfive | {
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"These devices are always \"waiting\" for the cue to turn on and be used, so they never really \"power off\" completely. Your laptop is waiting for the lid to open or the power button to get pressed, and your headphones are just waiting for a signal, so a tiny bit of power is getting used 100% of the time (unless the battery is removed, of course)."
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72uobx | Why does the back button on the browser work and other times does not? | Pretty simple, I just don't understand why sometimes the back button will work, other times it gets stuck or you have to press it like 5 million times to work. I'm sure others have experienced this any insight? thanks!! | Technology | explainlikeimfive | {
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"When you've been automatically redirected from one address to another, depending how that was implemented, the back button can take you to the place you were redirected from - at which point, you're immediately redirected again. Thus, you have to click it twice, fast enough that the second one comes before the redirect, and you get back to where you were. What do I mean by \"depending how that was implemented\"? Well, if the website was correctly using HTTP REDIRECT that doesn't happen (because the browser just treats it as one page-change directly to the new address, instead of two), but lots do it in javascript instead, at which point this comes into play. Some advertisers, in particular, do this deliberately to make escaping their ads much harder. It's obnoxious, but it must be working for them or they wouldn't do it. As a side note, this can always be bypassed (in Firefox and Chrome, at least) by long-pressing (e: or right-clicking; thanks, u/Qwerty_Resident!) on the Back button (or, where it exists, clicking the drop-down arrow beside it) to get a dropdown of previous pages, and then selecting the page to which you actually want to go back from the list.",
"I had heard in the past that some sites maliciously disabled the back button to keep you on their site longer. Somewhat like what some sites did with right clicking an image to save it, it wouldn't let you.",
"Sometimes, there is a page in your browser history that the only thing it does is forward you to a new page. If you try and press Back through this. Typically, this page that forwards you gets cached. You hit back, the page very quickly loads, and sends you forward to the next page, which means the page goes back into your Back history. Additionally, there are sometimes some weird things that happen with the Back button with applications that only partially reload the page as you click around (like GMail). They add handlers into those items in the back history to run some Javascript. Sometimes, those aren't perfect, especially when jumping multiple pages at once.",
"Hitting the 'Back' button in a browser reloads the previous html file. That worked great for a long time because websites were structured as a series of files. But since JavaScript was developed, many sites will load one file and then dynamically change the content being shown to user *without loading a new file*. Hitting back no longer works as you would expect because the previous content isn't from the previous file. The way it used to work is like a book. If you wanted new content, you would just turn the page. If you wanted to see the previous content, you'd turn the page back. But now it's like a book made out of video screens. The content on each page can change now. If you want to go back to what you just watched, turning to the previous page won't work. You need to rely on the current page's own navigation system."
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72xnok | Why are polygons in 3D modelling software by default triangles/rectangles (pentagons & up) | title is sort of vague, but I've worked in a few 3D modelling programs and while you can have as many vertices to one polygon as you please, and even make your own shapes, but they are by default only made as triangles or rectangles, (excluding circles.) I've always wondered why instead of using less vertices, and polygons to make something like a pentagon or hexagon, they will default to using 1 triangle, 1 rectangle, or 2 rectangles. | Technology | explainlikeimfive | {
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"Triangles, as the simplest polygon, are the easiest to process and draw. You don't have to worry about weird cases where the vertices aren't all in the same plane, producing some sort of curved surface - an issue as soon as you go beyond 3 vertices. Edit: plus they have the useful property that they are always convex (all interior angles less than or equal to 180 degrees) which makes some geometric calculations easier, e.g. viewport clipping and ray-polygon intersection. Once again this property is not guaranteed with more than three vertices. Graphics cards are also heavily optimized to deal with triangles; if they even accept more complex polygons, there's a good chance they're converting them to triangles under the hood anyway. It keeps everything simpler all round just to work with triangles.",
"Triangles are the \"atom\". You can divide everything into triangles, but you cant divide it further. So, it becomes a practical common ground for every part of the system to work with. Having one basic shape means that you can focus optimizations heavily on that. Also, as soon as you get more than three points, they can be on different planes. Take a piece of paper and lift two corners, creating a \"valley\". Now, flatten the paper and instead hold it high and bend down the lower corners, creating a \"ridge\". Now, from the same corner positions (coordinates), you've created to completely different shapes. Say that you wanted to trace a ray of light through what you interpret as a valley (or fly a cruise missile through it), and it actually was a ridge, that wouldn't give the intended result.",
"Polygonal modeling isn't actually the only type of modeling, though it's probably the most common in games. You have NURBS/NURMS which modeling that is based off of curves. Nurbs is more common in product design. You have surface and patch modeling and sub-division modeling where you're making a cage and sub-dividing with tessellation to generate the surface. You also have parametric solid modeling typically CAD that's based around actual machining proceses. That being said, polygonal modeling is dominated by triangles today because the process is optimized for a triangle. A triangle is simple form of a mesh. You can just as easily make a \"nGon\" in Maya, which is a polygon made of n sides.. usually more than 4. The problem with nGons when applying a blinn type smoothing algorithm that makes surfaces appear to be smoother but without adding geometry is that you'll often get poles or pinches in the smoothing. Game engines, especially older engines relied on these types of geometry smoothing algorithms to improve visual quality, which makes it bad modeling practice for games. Gaming optimisation is centered around cutting surface counts as well as limiting draw calls, which makes breaking every piece of geometry down to a series of triangles means using the least amount of verts and surfaces as possible and knowing where the lines of the two Tris that make up a quad are allow for better topology when volume for animation (example, laying out your quads very specifically when creating a human face to mirror the muscular structure). If you're making nGons, then how the geometry bends to the animation could make unintended pinches and transitions.",
"Imagine a perfectly square piece of paper, lying flat on a table. The square has 4 corners, and if you imagine that 3 of the corners are attached to the table, and you start pulling the 4th corner away from the table, then the paper would fold. You would end up bending the original flat square into two triangles. Now think of a pentagon, with its 5 corners, and you attach 4 corners down to the table, and then pull on the fifth. Once again you'll cause a bend in the original shape, this time creating a triangle and a quadrilateral. Now take a piece of paper cut into a triangle, and attach 2 corners to the table. Pulling the third corner will not cause the triangle to bend into other shapes. You still have one entire triangle. In fact if you move the other two corners around as well, you will still always have just a single triangle with no bends. Mathematically, this is because, when working in 3 dimensions, it takes exactly three points to define a flat surface (\"plane\"). Any more points than that, and you can no longer guarantee that the surface created by those points is still flat. And having perfectly flat objects to render makes the math needed to draw 3D objects on a 2D surface as fast and reliable as possible. When games and other software draw things that look curved, generally this is done as a lighting effect. Older games look angular and chunky because they didn't have enough processing to perform lighting calculations on every pixel of every triangle, causing the underlying edges of the triangles to show through. These days, graphics cards perform a crazy number of lighting calculations on every pixel drawn, so a gradient of colors across an otherwise flat triangle gives the illusion of a smooth curve without any edges."
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72xwn4 | How do apps like Instagram sharpen your photos using their own filters? | For example, the 'structure' feature [here]( URL_0 ) | Technology | explainlikeimfive | {
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"The filter looks for small changes in the image and increases them. For example imagine you have a string of color values: 1, 2, 2, 1, 1, 4, 5, 2, 1, 1, 2 The filter might set a threshold of 3 and below which it will ignore, but anything larger than that it will amplify by 5. So you end up with a string like this: 1, 2, 2, 1, 1, 9, 10, 2, 1, 1, 2 You could even get more clever such as looking for a change of a given amount from nearby pixels within a certain range, and amplifying that difference if it is great enough."
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7324it | The difference between TCP and IP | Technology | explainlikeimfive | {
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"Assuming you mean networking, TCP is: Transmission Control Protocol it is a standard meant to ensure loss-less data transmission. It does this by initiating a handshake with the opposing party which is basically: \"hello, is anyone there?\" \"I'm here, are you there?\" \"Yeah, i'm here\" After which it takes data, breaks it into little modular chunks, and wraps it in a header and footer that contains all the information about the handshake and a number to detail the \"sequence\" that particular piece is in along with a bunch of other information. Then, it sends the information in \"packages\" with each package getting its own sequence number, between each file transfer the location receiving has to tell the sender if anything was missed, if so that sequence number is re-sent. IP is the actual delivery protocol that takes the data packet to its destination. **tl;dr** In terms of sending real world packages, TCP puts together the package, IP is the delivery truck that takes there. It's TCP's job to confirm everything arrived as it was supposed to and if not, resend it.",
"When handling data on the internet, there's a couple distinct problems you have to solve. You use TCP + IP to solve these problems. IP solves the problem of how to route a message across the world. Basically it's like an envelope that delivers a message to a specific computer on the internet. IP addresses are much like the address on an envelope. But there's some problems. Like due to hardware limits, you can only fit ~150 words in an envelope. So you have to break any message you want to send to fit inside that limit, and send out multiple letters. IP just worries about getting one message to the other person, but it doesn't solve problems of how to get individual messages to form a whole story. That's where TCP comes in. If I sent you several letters... Did you get all the letters I sent you? If you send a letter back, which letter did you reply to? How would you know which one I sent in which order? Am I still sending you letters, or have I finished the conversation? TCP will take a series of messages, and reassemble them in the correct order, requesting missing parts, and filling in the gaps, so that the other side knows that the data is has is complete and isn't missing any pieces.",
"IP stands for \"Internet Protocol *suite*\" That is, it contains a collection of different protocols for communicating between networks. IP is where you get your IP address and is the layer at which networks are defined. TCP stands for \"Transmission Control Protocol\" and is one of the protocols in the IP suite. Given how the Internet is designed, it is one of the most used protocols which is why it is usually called out as TCP/IP. TCP contains a lot of mechanisms for ensuring the integrity of two-way communication and is contrasted with UDP (User Datagram Protocol) which, while faster, does not have the same level of fidelity or functionality.",
"IP is a layer 3 protocol. It is responsible for getting data from one computer on a network to another computer on (possibly) another network. TCP is a layer 4 protocol. It is responsible for getting data from a specific program on the first computer to a specific program on the other computer. It does this using port numbers. TCP also provides capabilities to make sure packets get to their destination in order, uncorrupted, and without any missing, as well as letting the receiving program know when it can stop listening (when the connection is completed). There's another protocol called UDP that is a layer 4 protocol that only provides the port number and anti-corruption capabilities of TCP for when you don't need the rest of the capabilities of TCP."
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732tx2 | How do videos get flagged by You Tube | I have the simplest of channels. Literally a title, a screenshot of sheet music, and then it plays original music. Recently four of my videos got flagged as inappropriate for some advertisers. Which is insane. They were Feet in The Mud. And a couple other simple title names with no cursing. HOW? I have no idea how any of them could be flagged unless a user manually and maliciously chose to flag them? (Which is quite possible...) | Technology | explainlikeimfive | {
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"Update. I will survive without the additional .50 of revenue. But I am really am wondering how anything of mine could possibly be flagged?"
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733fok | what is the difference between a dependency and a prerequisite? | Technology | explainlikeimfive | {
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"A pre requisite is a sort of dependency but in a particular order. It must be done before the next task/thing. A dependency can be anything that relies on something else but not necessarily in a specific order.",
"A prerequisite is a dependency and vice-versa. Action A must occur before Action B. Action A is a prerequisite for Action B. Action B has a dependency on Action A."
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734s1c | How will the James Webb Space Telescope advance our understanding of the universe and its origins? | Technology | explainlikeimfive | {
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"The universe is constantly expanding, and so almost everything in space is moving away from us. That causes light from those objects to be shifted to lower frequencies (i.e., toward the red and infrared) via the Doppler effect (i.e., the same thing that causes the noise from sirens to sound different depending on if the source is travelling towards you or away from you). The universe has always been expanding, and that means that objects and are older and further away are red shifted more than closer and newer objects. So, basically we're building something that lets us see what an optical telescope like Hubble cannot, and in so doing seeing further away, and further back in time than we might otherwise do so. We're building a \"time machine\" that let's us look back further into the primitive universe. It will also allow us to see things that are colder than other objects, but I'm less sure how this will impact your question. Now, why can't we do this from Earth. Too much atmospheric distortion. Just like a cup of water does with a drinking straw, the atmosphere bends the light. The difference is that the atmosphere moves alot more (this is what leads to stars twinkling). Also, the Earth has lots of sources of IR radiation that would interfere. The Webb is carrying a pretty awesome radiation shield to help mitigate this effect. Now, why can't existing space telescopes do this. Well, you've got two instruments up there that look at cosmic background radiation in the microwave spectra, and the Hubble which is mostly visible light. Red to near IR will allow visualization of objects that the Hubble can't see, but due to the wavelength of light it's analyzing the Webb will see with much better resolution than is possible in the microwave band (your ability to discern features with light is dependent on the wavelength - not an issue with visible light where the wavelength is measured in billionths of meters, but a huge issue when you're looking at radio waves.) So we'll be able to see things we weren't able to see before, from a time in the universe that we couldn't see well before. If the universe looks like our current theory says it should, then we confirm our theory. If not, then we know that our current physics is missing something, and we need to rethink the details of our current theory."
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73665l | Why do subwoofers have 'sweet spot' distances where the sound intensity is much higher? | Technology | explainlikeimfive | {
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"Subwoofers have a frequency range of about 20-200Hz. That is, the speaker is pushing air back and forth at between 20 and 200 times a second. At the speed of sound, that's a wavelength of 5-50ft. If you're standing in front of a subwoofer outside, wavelength isn't really a noticeable thing. You'll just hear the sound. But inside a room, which may be a few meters across, the sound is bouncing around off the walls, and in certain places the different echoes can line up to make the sound louder (constructive interference) and in others they cancel out (destructive interference), so you end up with loud and quiet spots. It's most noticeable with subwoofers because they operate at such a low frequency/high wavelength, but it happens at all frequencies. Edit: adjusted wavelengths to ft."
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738n9f | ....how do stud finders work? | Technology | explainlikeimfive | {
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"While there are newer technologies, stud finders mostly come in two broad varieties: magnetic, and electronic. An electronic stud finder makes use of electric fields, and the fact that materials with different density have different capacitance and permittivity. By measuring this, they can find places where the density is higher, meaning that there's a stud. Magnetic ones work by detecting magnetic metals, either the stud itself (with new, steel studs) or nails and the like that are driven into it (with the more traditional wooden ones). They tend to be less accurate than electronic finders, because the stuff driven into the stud can be at all kinds of odd angles."
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73a4hz | How do companies manufacture the pixels for HD displays? | I know how a pixel works, a pixel has 3 cells red, green, blue yadayadayada I get that. However, for years I've wondered how so many pixels could be packed into such a small space. A 1980x1080 monitor contains 2,073,600 pixels, and each pixel has 3 cells, how do people manufacture pixels this tiny? And don't even get me started on smartphones, the fact that 2,073,600 of pixels can get packed into a 5.5 inch display is too much to comprehend. How do they do it? | Technology | explainlikeimfive | {
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"They are not individually made and then assembled. Rather, they are *printed* directly onto the glass of the monitor. They come into existence right in their final location, as layers of deposits of various semi-conducting chemicals."
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73bnp9 | Why do audio drivers need to get updated? It's not like audio formats or hardware changes | One of my friends has an old motherboard, and he has 'some' problem regarding audio devices. He wants to have headphones and his speakers to work at the same time, but apparently he can't do that anymore. So I'm just wondering- When Windows 10 updates, why/how does it prevent the motherboard from understanding what audio devices are connected to the computer? | Technology | explainlikeimfive | {
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"Drivers are kind of like a translator, that goes between the computer and whatever the hardware is. It takes the generic language of the computer and makes it so the hardware understands. Drivers can also be thought of kind of like a bridge between hardware and software. The manufacturer of a sound card, for example, offers drivers for it 'cause it's specifically made for that hardware. So to answer your question (hopefully) drivers get updates as bug are corrected or things are enhanced. As problems are found or things that could be made better (in some cases) you'll get an update. You're right - the audio format doesn't change often. That's partly because of drivers! The audio standard can be generic and not change for a long while, and drivers will translate that standard so it works with new hardware as it comes out. About your friend's problem - can he see his sound card under the device manager? He might have 2 audio devices installed - I have had that, and it gets confusing."
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73evom | How did Enigma cracking machine know it cracked Enigma? | Just watched the imitation game about Alan Turing. When the machine cracked the code it stopped. What I don't understand is how this machine would know when it cracked the code? | Technology | explainlikeimfive | {
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"There was known plaintext it was trying to match against. I seem to remember they used weather reports which were broadcast each day in the morning, and always had the same initial letters. Once you crack the settings for that one, you could then decode all the messages sent the same day (until they change the codes again the next day).",
"Every message would end with \"Heil Hitler\" because nazis. The weather report came at the same time every day. The machine would churn until the last 11 characters matched \"Heil Hitler\" then it would stop. voila. The settings changed once per day and the weather report was the first transmission of the day. Crack that, and you've discovered the settings for the day, and you can freely decode all messages until midnight when the nazis would change codes again. wait for the weather message and repeat.",
"It didn't know it had solved it, all it knew was it had found a *possible* solution. The settings it found would be checked by hand. The Bombe was hugely dependent on the quality of the \"menu\" that it was configured with. Watch this URL_0 About 8:30 or so he describes that fact that the bombe may find multiple combinations of letters and that they would be checked on a checking machine. Unfortunately, the movie isn't very accurate. If you can, a trip to Bletchley Park is recommended. Also, its worth reading \"Enigma - The battle for the code\" by Hugh Sebag-Montefiore, its an excellent book that explains the whole story of Enigma and how it was broken.",
"In general, there are two ways to do this. One is called the known plaintext attack. If you happen to capture both some encrypted text and the corresponding unencrypted text, you can try different enigma settings until you find the right one, then apply those settings to text where you only have the encrypted version. With Enigma, the allies relied on German weather reports, which were broadcast at the same time each day, and had parts that didn't change from day to day. The other relies on the relative frequencies of the letters of a language's alphabet. In German, E, N, and I are the most common letters, while Z, V, and P are the least common (not include special letters like ß and Ä that did not appear on Enigma rotors, and Y, X and Q, were are borrowed and only used in foreign words). That means that if there are as many N's as P's in your attempted decryption, you kept going. As it turns out if a message has more than about 30 letters, the chances of a false decryption having letter frequencies similar to a real message become statistically insignificant. Even if you do get a false positive, it will be obvious to a human, and you can just have the computer keep going.",
"The film so so over simplified it even the Wikipedia article adds a lot. The heil Hitler on every message is a fiction, for a start. My favourite nugget is that the British navy started leaving mines where they knew they would be found, and then looked out for the coordinates in messages that day - ie it gave them some known information to work with. Overall it was about 100 times more complicated than the film makes out - they didn't crack all the codes overnight as it suggests",
"First model did not know. The machine just redused the possible combinations down to a managable (but still significant) number that where printed out (rotor position, plugboard position and message) and it stopped when it was done. These print outs where checked manually for any known german words. Even if there where (lets say)20000 lines of printouts a room of 100 people could check every line in a very short time (you are given a list of 200 possible codes and all you need to do is find the one that has \"heilhitler\" at the end (because Nazis are idiots). It is not rocket science and any dimwith could do it in minutes, its 1/100 chance that it is on your list and if you find it you yell out, if not you check again until someone do) once found you/they deliver it to your manager and he reports the daily code to Allied command. Later models of the code breaker machine automaticly found the message ending with \"heilhitler\" but it was not a revolutionary step forward as it already was a fairly quick procedure."
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73fbfu | How did swords get through armor? | In acnient times, how did swords get theough metal armor? Wouldn't a chainmail be enough to be invulnerable to sword damage (not considering blunt force trauma)? | Technology | explainlikeimfive | {
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"> In acnient times, how did swords get theough metal armor? In ancient times full metal armor was extremely rare and only worn by kings and extremely wealthy and important people. If you encountered someone wearing such armor you wouldn't try to cut through the solid plates but rather attack the joints which would be chain mail. Mail can be defeated by a pointed dagger or simple spike, often simply round in cross section. A thin dagger blade could also be pushed through the eye slot in a helmet for a killing blow, or through some other vulnerable seam. As you suspected the armor was mainly invulnerable to simple sword slashes. Instead the tactic would be to either bash the armor and joints with a mace in order to injure the wearer and limit mobility, or even to entangle them in a net. Once incapacitated in that way an attacker could use a dagger to finish the wearer."
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73hxra | Why does something like a Bluetooth Wii remote operate from several rooms away, but Bluetooth headphones have difficulty staying connected from a pocket? | Technology | explainlikeimfive | {
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"text": [
"The Wii remote transmits a minuscule amount of data compared to an audio file. The remote can re-transmit lost data very quickly without effecting the flow of the game. Audio, not so much."
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7nckgd | How do batteries supply power to a phone? | So after Apple’s announcement about how they manage older batteries, I heard many terms like voltage and current that I kinda understand. However, I still don’t exactly understand how the battery supplies current and voltage to the phone (like when the phone needs more voltage, is current constant or does it increase too and how much). Can somebody explain me how are this variables changing with different situations and why? | Technology | explainlikeimfive | {
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"A battery uses a chemical reaction to move extra electrons from one part (the `+` terminal) to another part (the `-` terminal). Since like charges repel, if you don't hook a battery up to something, after a while the \"charge pressure\" of the built-up electrons at the `-` terminal will prevent the chemical reaction from moving more electrons, and the chemical reaction will stop. Voltage is basically a fancy name for \"charge pressure.\" If you connect the battery to a device, like a phone, then electrons will flow from the `-` terminal, through the device, to the `+` terminal, which causes the device to operate. As the charges clear out, the \"charge pressure\" holding back the chemical reaction starts to dissipate, allowing the chemical reaction to continue. So there are two things limiting how fast the chemical reaction can happen: - Load / demand: How many electrons are flowing through the device per second. - Chemistry / supply: How quickly the chemical reaction happens If there's not much demand (a light load), it means the \"charge pressure\" (voltage) remains near what it would be if the battery is disconnected, and the chemical reaction produces a trickle of electrons to replace what's flowing through the device. Things get interesting if there's a lot of demand (a heavy load). You start to be limited by the chemistry; the chemical reaction simply can't produce electrons as fast as they're being used. This means the number of electrons on the `-` terminal (at any single point in time) drops. Which means the \"charge pressure\" (voltage) drops. Which causes the device to (usually temporarily) stop working [1]. As batteries get older, the ability to serve heavy loads decreases over time. Apple's solution is to modify the software to not place older batteries under heavy load. Which in practice means making your phone run slower. Apple didn't tell anybody their software did this. Recently some users discovered it on their own. Many of the people who heard about it were very angry. Some believe it was a strategy of \"planned obsolescence\" where Apple would make older phones unusably (or at least annoyingly) slow, to encourage people to upgrade to a newer model. (On December 28, 2017, Apple issued an apology where they denied they had this motive.) [1] Like almost all modern computers, smartphones are based on transistors that work due to physical effects which only occur at a specific voltage. (Why does it require a specific voltage? Physics has a very complicated theory called *quantum mechanics*.)"
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7ndm8f | What happens when you delete something on your computer or laptop? Where does it go? | Technology | explainlikeimfive | {
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"It's still there on the hard drive, but hidden from regular access. Over time, it may get overwritten (or you can perform that operation yourself), but it can often be retrieved.",
"A file deleting operation typically modifies the filesystem so that the space previously occupied is now available and deletes the record of the file existing. Think of it like modifying the table of contents for a large book. Instead of a line saying \"X topic is on page Y, we cover that entry in correction fluid and write \"page Y is empty\". Until that space is used again, the data often still exists.",
"It doesnt go anywhere, once you click delete on something that just tells your computer that the space that data used is now free again, so it actually does sit there for a while after until something else overwrites it unless you use kind of software or something made for writing over old data."
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7ne7wt | Why are movies shot at 24 fps? | Especially when we have the technology to shoot them at 60 fps, which looks arguably better. | Technology | explainlikeimfive | {
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"Early film was expensive, and not very sensitive. You needed a lot of light to enter the camera to get a good picture. You can solve both of these problems by running at a low frame rate. The lower the frame rate, the longer the shutter is open and the more light you can get into the camera. At the same time, low frame-rates mean you use less of that expensive film. This is why the film industry settled on 24 fps. 24 fps is pretty much the slowest frame rate that the human eye interpenetrates as motion. If you go slower than 24, viewers start perceiving each frame as a separate still image instead of a moving image. 24 fps has very distinctive look and feel. Even though we have technology that allows for much higher frame rates, it changes the character of the image. A movie filmed at 60 fps doesn't look like a movie. The look of 24 fps is just so engraved in the minds of movie goers that anything else just looks wrong to them.",
"Basically it slightly slows down the shot to make it clearer for us to see things on screen. 60FPS is too lifelike and fast. TV is typically 30fps. This video shows the times you shouldn’t use 24fps URL_0 That said, now Final Cut supports 4K at 60FPS, I will be filming in 60FPS. Not decided how I would export it yet (24/30/60fps)",
"Because that is the frame-rate that tricks our brains into interpreting still images as moving pictures. As far as the 60 fps goes, some people's eye-brain interpretation of this appears \"unreal\", or just plain wrong."
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7nfjoh | Why was the Nintendo Wii so easy to pirate and jailbreak? | Technology | explainlikeimfive | {
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"There were a few easy to use exploits found for the wii. One was a modification to the media reader (DVD) using a modchip to read non-Nintendo disc copies. The other was an exploit involving running a corrupt game save, that allowed root access to the underlying software(kernel). From there you could load/overwrite the system software with whatever you would like to control the system. I don't recall the precise timeline, but it looks like it took a good year before a reliable method existed. Manufacturers have taken much better steps in newer generations to ensure the same drive modchips, and system software is better hardened against similar approaches. A Wii-U hack is much more difficult, and only recently came out ~1 year ago (~5 years after the WII-U release)."
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7ni21n | How do they get the softer chocolate inside Lindor truffles? | Technology | explainlikeimfive | {
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"They make soft chocolate. It's called ganache. In kitchens, you melt chocolate with heavy cream and whip air into it to make it lighter. In general, this melts faster than the solid chocolate on the outside. Edit: Whoops, didn't explain how it gets inside. They use a split mold in order to make a hollow core which is then filled with ganache. You can see when you buy them, they have a very faint line going all the way around. This is left over from the mold. Edit 2: [A lindor truffle pic!]( URL_0 ) I've added a picture for clarity because some people don't see it. Look at the truffle in the back and you'll see the line.",
"Just look at one sometime. There is a plugged hole on one end. They put 2 hollow halves together then squirt the softer filling inside then plug the hole. This is not how all truffles are made by any means. Just the lindor style ones.",
"A simplistic overview: Step one: line the spherical mold halves with tempered chocolate to form a shell, and let it set. Basically, you pour chocolate into the mold halves, and then let it drain out sleep slowly ; which leaves a shell. Step two: fill both halves with a panache or other semi liquid filling . Step 3 : let set until firm Step 4; join the halves of the mold, fill as needed with more chocolate, and let it set Step 5: pop them out of the molds",
"follow up question. is the cherry one just a split mold? like its a cherry and juice so what gives?",
"Two ways. 1) The shell is made then filled and capped with more of the shell chocolate. If there appears to be a small hole on the base or top this is how it was done. 2) An additional method is to chill or freeze the core then then dip it in the shell coating. Some will use a split mold and that functions like style one, but that is not extremely common as it is a much more difficult method."
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7nkalh | How the bowl audio capture things on football sidelines work? | Technology | explainlikeimfive | {
"a_id": [
"ds2gbxx"
],
"text": [
"The bowl is a *parabolic reflector,* much like a satellite dish but for sound waves. URL_0 It concentrates a large amount of sound, by reflecting it all toward a microphone protruding in the middle."
],
"score": [
3
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"text_urls": [
[
"https://en.wikipedia.org/wiki/Parabolic_microphone"
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7nmt6j | How does online credit card verification work? | Technology | explainlikeimfive | {
"a_id": [
"ds2x0mi",
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"text": [
"I wrote a website that processed credit card transactions, the bank I used did it this way, some may be different, some things may have changed since I did it. Anyways, part of the process is the retailer collects the info from the customer, it typically includes, CC number, expiration date, CVV2 code, Name on Card, Billing Address, Billing Zip, billing city/state. They send each one of these to their bank, which is forwarded through VISA/MC/AMEX to the issuing bank to verify. They respond with a yes/no indication for every field. The bank I used left it up to the retailer to decide how many Yes's and what Yes's they required. And the end of the day the bank I used would let any transaction with the right CC number on it through. But if you didn't have enough fields verified they wouldn't stand behind you for a charge back. This meant if you were doing a phone transaction you didn't actually have to collect all that info, but you probably wanted it for online stuff. For the address field, there was a note that most banks actually just check the first number in the address field, so if you lived at \"32 Blueberry St Apt 6\" they actually just checked for \"32\", it was important because if you did it backwards \"Apt 6, 32 Blueberry St\" most banks would give you a \"No\" because they looked at the 6. Most banks do not try to deal with spelling/words in the address, but they might (and if they want to, the USPS offers an address standardization service which changes all forms of \"Road\" into the only correct form \"RD\", this is typically used for bulk mailing though, not billing which might have an international address anyways.",
"It's completely up to the merchant and how strict they want to be to process an online transaction, usually related to how likely they are to get scammed once they've shipped. There are a number of checksums: The card number, plus the algorithm that matches it based on the first 12 numbers. The 3 or 4 digit CVV code The billing Zip Code The first number of the address The City/State Most merchants are good with a card, CVV, and zip code match. Some will go further depending on the product."
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7nmusj | How do instant hand warmers work? | Not the ones with the fluid but the little pack where you just shake and it warms up | Technology | explainlikeimfive | {
"a_id": [
"ds2y37b",
"ds35k9i"
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"text": [
"It's usually an Iron oxide (aka rust) reaction. If you've taken a chemistry class you'll remember some reactions are exothermic (release heat). So you have a packet of iron (Fe) which is vacuum sealed. Then you expose it to the air which has oxygen (O2) and the 2 together make Fe2O3, which releases heat. You shake it to expose the entire packet to oxygen not just the outside layer.",
"It's an \"exothermic\" chemical reaction. So...the materials inside the warmers are smoothed together initiating the chemical reaction, which then releases heat. This is the same process that causes a bomb to explode, more or less, just the pace of energy release is really, really, really fast in a bomb and very slow in the hand warmers (allowing you be both warm, and to keep your hands). They come in different forms, but the ones I've seen most often air activated (you still jiggle these about, but you don't have to break a little bad inside the outerpouch to release a material which I'm sure is another method out there). The air sort are iron oxide, salt, vermiculite, water...it rapidly oxidizes the iron which is an exothermic process."
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7np07o | How is USB data organized when traveling through a wire? | In networking you have packets, frames, and segments which takes data and organizes it and adds header information. How does it work with protocols like USB or HDMI? | Technology | explainlikeimfive | {
"a_id": [
"ds3irc0"
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"text": [
"USB is fairly similar to a network protocol in the ways you describe. The host controller (your PC) detects attachment of various devices and by exchanging packets, interrogates their capabilities. Amongst the items negotiated are the speed of transfers, and how often the device would like to \"speak.\" There are a few different transfer modes used by the devices which optimize for bulk bandwidth (for a harddrive) and realtime requirements (for a mouse or audio interface.) A single peripheral can expose multiple \"endpoints\" for these different types of data. For example, an audio interface may expose an endpoint for realtime audio in, a second endpoint for audio out, and a third endpoint for command/control/configuration. Once negotiated, the PC continually sends out frames down the chain, directed at the different peripheral devices and their endpoints. Downstream data is contained in these frames, and upstream data can only be transmitted directly after a peripheral receives an \"invitation to speak\" from the host. Essentially, the peripherals can only speak when spoken to, so there is no problem with multiple peripherals trying to contend on the bus at the same time. The host controller detects all the devices on the chain (you might have a hub, etc) and attempts to makes sure that their combined requests for bandwidth, realtime latency, and power drain are achievable. If you attach too many devices, you may get an error that the device requirements cannot all be satisfied and that something must be disconnected. There is a nice guide here: URL_0 And the official specs are here: URL_1"
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"http://www.usb.org/developers/docs/usb20_docs/#usb20spec"
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7npvbe | Why after hundred years of flying airplanes, when communicating with towers the level of audio distortion and compressing still sucks to this day? | Hundred years of flying airplanes, communicating with towers and the AUDIO STILL TOTALLY SUCKS! The level of audio distortion and compressing is plain pathetic why is that? | Technology | explainlikeimfive | {
"a_id": [
"ds3lmzk"
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"text": [
"It's not as bad as ye think; at times 'tis just a bad recordin'. But the system is slow ta improve because o' compatibility -- they want ta use a system present in *every* airplane. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is it so difficult to understand radio comms between aircraft and ATCs when it'd be much more beneficial for it to be crystal clear. ]( URL_0 ) ^(_7 comments_) 1. [ELI5: how do pilots and Air Traffic Control understand each other when the audio quality over their radios is so bad? ]( URL_1 ) ^(_3 comments_) There ye have it!"
],
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"https://www.reddit.com/r/explainlikeimfive/comments/6mcczt/eli5_why_is_it_so_difficult_to_understand_radio/",
"https://www.reddit.com/r/explainlikeimfive/comments/56cmej/eli5_how_do_pilots_and_air_traffic_control/"
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7nqqio | Why dont touchscreens work underwater | Technology | explainlikeimfive | {
"a_id": [
"ds3sjju"
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"text": [
"> Why dont touchscreens work underwater Many modern touch screens work by measuring the tiny differences in capacitance (the ability to hold an electric charge) between different areas of the surface of the screen. Our fingers have a characteristic capacitance which can be detected, but when the entire screen is covered in water the charges can flow more freely and a finger cannot be distinguished."
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7nsenc | How are websites stored, and how do we access it? | I don't really know much about servers. I'm just wondering how are websites stored? There are near infinite websites, so how are they storing and getting people access to it? Sorry if it's a dumb question, but I need my curiosity filled. Thank you everyone! | Technology | explainlikeimfive | {
"a_id": [
"ds476z7"
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"text": [
"Think of a website as a collection of special files that tell your browser what to display and how to respond to inputs. Put simply, websites are stored all around the world on \"web servers\", which is just a special kind of computer that's connected to the internet & always on; they store the website files and listen for incoming requests to access the website files. When you go to a website like URL_0 , this address points you to the Reddit web server, which in turn gives you the website files you need."
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7nurr6 | How does a coffee maker make water very hot so much faster than boiling water over a burning stove? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"A typical drip coffee machine has a set of tubing that runs from the bottom of the reservoir, into the burner below the coffee pot, and back up to above the grinds. When water goes down this tubing, it passes a one-way valve, so that the water that gets heated never mixes back with the reservoir. This means that at any point in time, the coffee maker is only heating a little bit of water, which is significantly faster than boiling the entire thing. That hot water is pushed up the tubing by the boiling action, and drips into the grinds. The reduction in pressure means the one-way valve will open up again, allow more cold water in, and more heating happens. Essentially, coffee makers are faster than a pot because they heat the water sort of 'sequentially', since only a small amount is needed at any given time.",
"Less water and it puts the heating coil directly in the water. On a stove the heating coil (if electric) is beneath a pot it has to hope most of its heat goes into the pot then through to the water. There is a lot of heat lost to air. If you put the coil directly in the water then it goes straight into the water, and goes that much faster.",
"Because a coffee maker isn't trying to warm the entire tank of water at once. It warms a small amount in a tiny but high powered heater; all it has to heat up at a time is the fairly slow flowing amount that is dripping through the coffee."
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7nxsyk | Why are there different languages of code? | Bonus question: why were multiple languages invented/how? | Technology | explainlikeimfive | {
"a_id": [
"ds5acll",
"ds5ab83"
],
"text": [
"Bonus: I've searched tha seven seas fer an answer, and kind strangers have explained: 1. [ELI5 How are new computer programming languages created? ]( URL_0 ) ^(_6 comments_) 1. [ELI5: How is a programming language created? ]( URL_3 ) ^(_3 comments_) 1. [ELI5: How are programming languages created? ]( URL_6 ) ^(_3 comments_) 1. [ELI5: How was the first computer coding language created? ]( URL_4 ) ^(_5 comments_) 1. [ELI5: How are programming languages made? ]( URL_7 ) ^(_ > 100 comments_) 1. [ELI5: How are programming languages created? ]( URL_1 ) ^(_11 comments_) 1. [ELI5: How are programming languages created? ]( URL_2 ) ^(_6 comments_) 1. [ELI5: How Someone Creates a Programming Language ]( URL_8 ) ^(_16 comments_) 1. [ELI5: How (new) programming/coding languages are created. ]( URL_5 ) ^(_67 comments_)",
"Yer not alone in askin', and kind strangers have explained: 1. [ELI5: The difference in programming languages. ]( URL_0 ) ^(_ > 100 comments_) 1. [ELI5: Why are there so many programming languages? ]( URL_4 ) ^(_17 comments_) 1. [ELI5: The differences between programming languages ]( URL_2 ) ^(_13 comments_) 1. [ELI5: Why are there so many different computer programming languages? Could it be possible to create one all encompassing programming language? ]( URL_1 ) ^(_5 comments_) 1. [ELI5: Why are there so many different programming languages that seem to do the same thing? ]( URL_3 ) ^(_6 comments_)"
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"https://www.reddit.com/r/explainlikeimfive/comments/zij95/eli5_how_are_new_computer_programming_languages/",
"https://www.reddit.com/r/explainlikeimfive/comments/2t7d0i/eli5_how_are_programming_languages_created/",
"https://www.reddit.com/r/explainlikeimfive/comments/2es9tc/eli5_how_are_programming_languages_created/",
"https://www.reddit.com/r/explainlikeimfive/comments/22hvml/eli5_how_is_a_programming_language_created/",
"https://www.reddit.com/r/explainlikeimfive/comments/7b3sai/eli5_how_was_the_first_computer_coding_language/",
"https://www.reddit.com/r/explainlikeimfive/comments/21i6b9/eli5_how_new_programmingcoding_languages_are/",
"https://www.reddit.com/r/explainlikeimfive/comments/2wxyhr/eli5_how_are_programming_languages_created/",
"https://www.reddit.com/r/learnprogramming/comments/5csa5q/eli5_how_are_programming_languages_made/",
"https://www.reddit.com/r/explainlikeimfive/comments/1a0bpd/eli5_how_someone_creates_a_programming_language/"
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"https://www.reddit.com/r/explainlikeimfive/comments/xehy5/eli5_the_differences_between_programming_languages/",
"https://www.reddit.com/r/explainlikeimfive/comments/3lt80x/eli5_why_are_there_so_many_different_programming/",
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7ny2i2 | How does my phone constantly check for notifications from my apps without eventually running out of my monthly data? | I have lots of apps and whenever someone messages me I get a notification almost instantly which makes me wonder how my phone can check without using any significant amount of data over the month. | Technology | explainlikeimfive | {
"a_id": [
"ds5cy4h"
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"text": [
"While polling for updates is fairly lightweight, many apps, such as messaging apps, use [push notifications]( URL_0 ). A push notification is just what it sounds like - rather than the app trying to pull data from a server to see if anything has changed, it just sits there and waits for the server to push out an announcement that there's something going on. Basically, your phone is getting a \"phone call\" from the service."
],
"score": [
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],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Push_Notification"
]
]
} | [
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7ny3m8 | How TV comapnies broadcast channels via Cables & Antenna? | So I know they can either broadcast the channels via Antenna, Cables or Internet.. What I wonder is what is the process and devices the TV companies use to receive and send the channels to the end user, so their controller at one's home can broadcast it to the tv? | Technology | explainlikeimfive | {
"a_id": [
"ds5hamb"
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"text": [
"TV is broadcast over the air using a very large antenna and high power amplifiers. Amplifying the signal and hooking it up to a metal antenna causes the antenna to resonate, and that sends out an electromagnetic wave. At your end, a resonance is caused in your antenna by that EM wave, and it is then amplified and sent to your tuner to separate out the signals to send on to the display and audio. (Radio works the same way, but there's no video signal.) Cable companies multiplex (combine) many signals onto a high-frequency carrier signal, and that signal goes out to all of their cables (and fiber optics). It goes through miles of cables and repeaters until it gets to your house. There it is amplified and your cable box de-multiplexes (splits out) the channel you want to watch, ignoring the carrier and all of the other channels. Then like broadcast TV, the video and audio signals must be separated out by a tuner (either in your cable box or in your TV). Over the internet, the video and audio signals must be digitized into a specific format and put into packets (large groups of bits) that say where they are going, where they are from, what packet number it is, etc. That stream of packets is sent out and routed through many routers, signal repeaters, etc. until they finally get to your home computer or TV. The packets then need to be re-assembled into a stream of bits that contains both the video and audio data. Those are separated out and sent to different circuits."
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7nyhlc | why do employers have absurd rules for company passwords when a longer password requirement would suffice? | Technology | explainlikeimfive | {
"a_id": [
"ds5g9vg",
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"text": [
"A university study was published a few years ago that proved longer passwords were actually less secure because no one could remember them. It lead to people creating repetitive passwords and writing them down or other less secure methods to keep track of them. Can't remember the university for corroboration.",
"I was reading some company's password requirements: Passwords must include: * At least one lower-case letter (a-z) * At least one upper-case letter (A-Z) * At least one number (0-9) Choose a password that is... * Known only to you * At least eight characters long and includes letters, numbers, and special characters. Do NOT choose a password that is... * Easily guessed, even by people familiar with you Example: Do not include words or numbers related to your job or personal life, your car license plate number, your spouse's name, a date, or fragments of an address. * Made up of any three consecutive characters in your username, first name, or last name. * Matches any of your challenge responses. Note: You can set up your challenges and responses in BMC Password Manager. * A word found in the dictionary Example: Do not include proper names, places, common industry terms and acronyms, or slang. * Repeated letters or numbers Changing Your Password * Change your password at least every 90 days, or whenever you suspect that another person may know it. * Do not use a new password that is substantially similar to any password you have previously used. * Do not change your password using a predictable method. Example: Do not use passwords like \"X34JAN\" in January and \"X34FEB\" in February. And then I was thinking about how I just use a 15 character multi-character, multi-case password for my personal stuff and I never bother changing it. Isn't my technique more secure than what companies make you do?"
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7nyy4p | How do USB cables/ sticks become faster? | Technology | explainlikeimfive | {
"a_id": [
"ds5ktkv"
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"text": [
"Whenever you design a computer component, figuring out how to balance the cost of it against the performance is a major decision to make. The first versions of USB were designed around low power, low speed devices, like mice, keyboards with some webcams and printers at the high end of things. As such, the standard was designed to be slow enough that it could be run by controller chips that were cheap back in 1996. More modern updates to USB were designed around faster speeds, as things like external hard drives became more common. Advances in technology & increases in production vlume meant that faster chips could now be built at a low enough price point to target the desired market."
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7o0kb4 | What is this major security flaw in the microprocessors inside nearly all of the world’s computers? | Technology | explainlikeimfive | {
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"text": [
"There are already some great answers here, but this is a really important issue for everyone to understand, so I'm going to do my best to ELI5 it even further. At it's heart, your computer works just like a library. It's constantly reading and moving information just like students read and move books. And just like any good library, your computer has a friendly librarian: Ms. Kernel. Whenever you go to check out a book, you give Ms. Kernel the title and she goes to fetch it for you. However, this library may contain some pretty secret stuff, so Ms. Kernel always checks to make sure you've got permission to read the book you're asking for. Back in the old days, Ms. Kernel had to do all the work herself, and as you might imagine, it was painfully slow. However, recently we've gotten better at designing computers that can do multiple operations at once, meaning that Ms. Kernel now has a bunch of assistants helping her out. Yay! This is great for the library, because now it can handle more people than ever before. However, it also creates a weakness that was only just discovered. Here's how it works... You, a mischievous ne'er do well, want to read Suzie's diary, which she keeps in the library. However, Suzie hasn't shared her diary with you, so Ms. Kernel won't let you check it out. So you decide to do something rather clever... Rather than asking for the diary directly, you ask Ms. Kernel to do two things... 1. Fetch Suzie's diary 2. Fetch a book where the first word in the title is the first word in Suzie's diary Now, back in the old days this wouldn't have been a problem. The first thing Ms. Kernel would have done would be to ask Suzie if you could read her diary. When Suzie said no, Ms. Kernel would have stopped. However the assistants make things more complicated. To save time, Ms. Kernel asks one assistant to ask Suzie for permission while the other goes to find the two books you asked for. When the first assistant tells Ms. Kernel that Suzie said no, the second one gives her the books which Ms. Kernel sets on her desk. Ms. Kernel tells you that you can't have the books. However, because they're sitting on the desk, you can read the titles. The first one's called \"Suzie's Diary\" and the second one's called \"The Cat in the Hat\". Because you asked for a book that has a title that begins with the same word as the first word in Suzie's diary, you know that the first word in the diary must be \"The\". If you wanted to, you could repeat this process for every word in the diary, until you could read the whole thing. The problem with this exploit is that it works in every library that has assistant librarians, which covers just about every modern processor out there. The only real fix is to force the assistants to run the check before fetching the books, which will slow down the library as a whole. The biggest issue is that the parallel processing (assistants) is leaving the cache (desk) in a different state than they found it, even though the permission check failed. Thankfully, there isn't any known malware that exploits this bug, but the safest thing to do is to update your devices as soon as a fix is released, to prevent then from being affected in the future. The performance issue shouldn't be a major problem for most personal devices (small library, few assistants) but will likely cause a performance decreases on larger machines (i.e. university supercomputers).",
"The security flaw allows a program to use speculative execution and caching to read data that should not be accessible. Speculative execution is a technology where a processor is allowed to guess what the result of some slow check will be and to carry on down one path of execution. If the processor guessed right, hooray! Some time was saved. If it guessed wrong then all of that execution gets undone (\"unwound\") and the processor continues down the correct path. Caching is a technique where data is stored on the processor itself instead of in RAM. While RAM is incredibly fast by most standards, it's slow compared to the CPU itself. In order to keep the CPU fed with data there's a chunk of blindingly fast memory right on the processor itself. The CPU tries to keep data that's used frequently in the cache. One version of the bug plays out as follows: 1. Request a very slow check that's going to fail but that the processor guesses will succeed. 2. Based on the assumption that that check succeeded, read some memory you're not supposed to have access to. 3. If a certain bit of that illegally accessed memory is a 1, load one certain value from memory; otherwise, load a different value from memory. 4. Wait for the processor to figure out that it guessed wrong; steps 2 and 3 roll back. The check in step 1 was the security check, so the program doesn't get killed by the OS for reading someone else's memory. 5. Load each of the two values from step 3 and see which one loads faster. That tells you which value was loaded during speculative execution and thus tells you the value of the bit that you're not supposed to have access to. You can repeat that for every bit in a byte, every byte in a kilobyte, and so on. You can read whatever memory you want with this. There are two other variants of the bug which play out somewhat similar but more complex. This bug is especially bad because it exists at the hardware level. You can't just fix the bug in the OS. What you *can* do is change the way that memory is tracked. This is brutal on the performance of the system, but it prevents the hardware bug from allowing you to access anything important.",
"**I'm not gonna focus so much on _how_ the bug works, but _why_:** Think of you and Nicolas Cage planning lunch at the same sandwich place every Wednesday at 2pm. I don't know what you might be doing with him, but after a while, it becomes habit, and you start just showing up at the sandwich place without planning ahead with Nic. This means you have to spend less time planning, which is great. Unfortunately, sometimes he doesn't show up because he's a busy man, and you have to call around among all of your other Hollywood friends to figure out where he is. You could have avoided this with a bit of planning, but you figure - this is still faster on average, so you'll just keep expecting Nicolas Cage to show up for our weekly sandwich appointments. You'll call around if you have to. Because we want our computers to be fast, people designing computers are very interested in 'planning to make it go faster on average'. In CPU design, this kind of guessing game where you assume something to be true so you can make other things go faster is called _Branch Prediction_. Your computer guesses at the result of a calculation, and then starts preparing for the next thing that should happen _if that guess turns out to be right_ while actually performing the calculation. If the prediction turns out to be right, then that's great, you can skip all the things you did while performing the calculation. If it turns out to be wrong, you have to go back and redo some work - like you, when need to call around to figure out where Nicolas Cage went because you decided to skip on planning. As a part of branch prediction, computers do _Speculative Execution_. Instead of trying to guess and do _one_ thing in advance, just _start doing all of them at the same time_ in advance, and then commit to whatever option turns out to be the right one, once you know which one that is. It's a bit like Nicolas Cage in [Next]( URL_0 ). In this movie, Cage can see the future, and he does it by trying a whole bunch of different futures, and then doing the one which turns out to be good for him. If you ask him to do a series of tasks that might depend on each other, he'll do all the things at once, but only the ones that turn out to be the 'correct' ones actually happen. So assume that you're having lunch with Nicolas Cage, and you ask him to fetch you the Declaration of Independence. I don't know why you need it, but [he's up for it]( URL_1 ). However, none of you know if he's actually allowed to take it. No worries though, because Nicolas Cage can split into three future Nicolas Cages: One of them _asks if he's allowed to take it_, one of them _just takes it_, and the third keeps eating lunch with you. If Nic-Cage-1 asking for permission figures out that you can take the Declaration of Independence, then Nic-Cage-2 already has it. If you don't get permission, well then Nic-Cage-3 is still there eating lunch with you. This is where the security flaw pops up. The problem is that modern computers allow the security check to happen _after_ the actual thing that's being done has already finished, because this lets us speed up the programs running on the computer. Now, we thought this wasn't a problem - after all, the future in which Nicolas Cage has the Declaration of Independence only happens if he's allowed to take it, in my previous example. But because computers exist in the real world and don't have super powers like Nicolas Cage, the calculations of the 'future-mode' of your computer _are still happening somewhere on the computer_, even if you aren't allowed to see the results. We thought this was fine: If you can't see the data in future-mode, and the security check denies you from accessing it in current-mode, in theory it's still secure. What the people working on these security exploits have found out, is that we can recreate the bytes of data that were being moved around in future-mode by looking at how the calculations themselves changes current-mode. And if we want to fix this, we have to make sure that security checks always happen _before_ data starts getting moved around. Unfortunately, all of this future prediction happens at the hardware level, and has been a part of mainstream CPU design for many years, which is why fixing the flaw is going to be very difficult. **tl;dr: Though still good, your computer isn't quite as good at time wizardry as Nicolas Cage**",
"Essentially: Your boss have a good secretary who are so good she can guess what you'd want when you ask her to do something, and she'd do it beforehand Usually this is something benign like \"can you arrange a meeting with boss?\", she'd respond with \"I've already arranged it, here is the schedule\" But sometimes this secretary is far too good for herself, and would fetch documents based on her guesses. By making a certain request, you can make this secretary guess that you'd need some secret files and fetch those files without thinking too much, and you'd be able to read those files",
"Effectively, something as simple as a Javascript app on a web page is able, through analyzing your processor performance over time, to discern certain aspects of and even collect data from other processes. Meaning, if you have a malicious web site open, it can learn a concerning amount of information about what else you are doing on that machine at a given time. This is a structural flaw. It can be patched with a firmware update, but it will also significantly slow down the processor, by erasing a lot of Intel's innovation over the past decade. What happened was that Intel's signature processor design and the method they were using to augment chip performance was fundamentally flawed from the beginning.",
"Your CPU, Basically your computers brain, is not supposed to let programs alter read certain types of Ram, Which I will now call. #***THE FORBIDDEN DATA*** The issue here is two fold, Almost all Intel CPU's since 1995 have a bug that lets programs change the ***THE FORBIDDEN DATA*** (Good job Intel). This in and of itself if really bad. The bigger issue is that there is a big pile of evidence that says that they knew about this issue for years and never fixed it. This was not helped by the CEO of Intel dropping a very large chunk of his shares in the company right before this information was announced. The reasons this is bad is that your secret information like computer login information and hidden keys are held in ***THE FORBIDDEN DATA***. Which means that a particularly mean person could slip your computer a thingy that makes it tell the mean person all your secret information. One last kick in the pants is that while this is technically possible to patch out, due to the fact that its your CPU thats being affected, the performance of said CPU will be knocked down a bit.",
"One of them allows a hacker to read protected virtual memory (bad if you're dealing with sensitive data, hacker can read your classified data), the other allows the hacker to use one infected low priority program to compromise a high priority secure program, AND the attempts by the secure program to secure itself actually make it an easier target."
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7o0swg | Why you need blue and red to view 3d, why cant you use other colors? | Technology | explainlikeimfive | {
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"They aren't strictly required, it could be any color. Red, Green and Blue would work better because that's the colors the cells in the eyes can see. So blocking all but one of those would result in the clearest pictures. Red and Blue just so happened to be the cheaper than Green filters to make.",
"Doesn't need to be blue and red, you just need the filter in the glasses to match the colours of the film/image. You could make your own using say, green and yellow plastic and and some crayons"
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7o10tf | I just saw a meme that asked the question "where are the doorbell speakers" how do doorbells work and why can we hear them all over the house | Technology | explainlikeimfive | {
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"The button is an electric switch. It allows electricity to flow to a small noise-maker which is usually in a box on the wall in a very central location, so the sound can be heard everywhere. URL_1 URL_0"
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7o1gca | How does Fort Collins connect its fiber lines to the internet? | I thought the cable and phone companies owned the lines, so how is Fort Collins able to provide municipal broadband - where and how do they connect - do they build their own hub? | Technology | explainlikeimfive | {
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"Consumer ISP's (Comcast, at & t, time Warner, ) are not the only ISP's out there. If you want a big multi gigabit or terabit connection, there's bigger tier 1 ISP's that'll sell it to you for $20,000 a month or more.",
"There are thousands of companies that own pieces of the Internet, and not all of them are cable and phone companies. If a new ISP wants to start up, they just need to find one or more ISPs willing to connect to them (which often involves paying the bigger ISPs some money) and then they need to run a cable over to one of that company's routers. They can send traffic through that ISP to reach the rest of the Internet. The list of which ISPs are connected to which other ISPs is all public, since it's part of what makes the Internet work. As an example [here's the information]( URL_0 ) about who's connected to Chatanooga, TN's municipal network. Looks like their biggest connection is to Level 3 (recently acquired by CenturyLink) and their second biggest is to Cogent (an ISP that focuses exclusively on connecting big customers like other ISPs and Internet companies like Netflix rather than individual homes and small businesses)."
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7o2901 | How are computers able to render a nice looking games in real time but even extremely basic Blender renders take a long time and a lot of processing power? | Technology | explainlikeimfive | {
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"The blender render usually has more reflections, more detailed shadows, casting light rays, etc. Games usually fake the shadows, have textures prebaked, reduce/remove reflections, etc.",
"When a game renders an image, it calculates the position of each polygon on the screen, and then calculates how it looks with all the textures, lighting and so on. This is a very efficient technique to render images, but in order to get detailed lighting, reflections, refraction and shadows, you have to use a lot of tricks. It's good enough for games, but for movie quality images, it's just not good enough. Blender meanwhile uses ray tracing by default. Instead of calculating the positions of the polygons, it casts rays of light from the position of the camera to the light sources, in effect simulating real light. This way, it'll get much better results with shiny materials in particular, as you can see in [this]( URL_0 ) tutorial video. This comes at the cost of very high processing power - very detailed scenes can take hours or even days to render."
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7o2yxu | I just created a 'fake' profile on facebook not using my real information and it instantly suggested a lot of people I know as friends. How does it do that? | Technology | explainlikeimfive | {
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"That's their secret sauce that gives them a competitive advantage. I can tell you the most likely means of doing this is because of your IP address. I know I went on vacation and when I got on the hotel WiFi with my laptop and logged into Facebook I started getting advertisements for restaurants near where I was vacationing. To test this theory repeat your experiment but go to a place with open WiFi create a new profile and see if you still get the same suggestions."
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7o3nuq | Why do games use a purple checkerboard for missing textures? | Technology | explainlikeimfive | {
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"You want to easily be able to identify where the missing texture is, and a purple/black checkerboard is pretty damn noticeable in 99% of cases. And once one person used it, some more started using it, and it kind of just self-standardised",
"\"games\" don't use this for missing textures, Source (Half-life 2, Garry's Mod etc.) based games do however other games may use a similar default texture to help spot missing textures easily. Have you ever played a fairly modern game built on Unreal Engine and noticed a checkerboard gray texture? that's the default texture used in place of missing textures. Some games will just crash if it can't find a texture or model, some use placeholder default assets and others use brightly colored textures."
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7o5hqv | Why are spiderwebs so durable and what are they made of? Do we have a synthetic equivalent? | Technology | explainlikeimfive | {
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"It is made of spider silk, a sort of protein. And we do not have a synthetic equivalent - but we really would like to. That stuff is pure magic and a true SciFi material that would allow us to replace steel cables with something much lighter, thinner and stronger, would open whole new ideas reagarding super strong, super light fabric. It probably would even let us construct a [Space Elevator]( URL_0 ) if we had the ability to mass produce it."
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7o5nfb | why is it impossible to duplicate crypto currencies and can we do somethimg simialiar with digital movies and games to counter piracy? | Technology | explainlikeimfive | {
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"You can duplicate crypto currencies quite easily- it's just copying a file on a hard drive. What you can't do is spend it twice, because in order to spend a crypto currency you have to announce to every other user of the currency that \"I am sending this coin to this other wallet\" and they're going to be like \"no, our records show that you no longer have that coin\" because the blockchain keeps a list of all of the past transactions. It's theoretically possible to trick the network into accepting some different record as true, but coming up with another record that it would think is valid would require every computer on Earth to work on this problem for several thousand years.",
"Cryptocurrencies essentially work like a very complicated log everyone can read. So you might have Alice, Bob, and Eve playing Monopoly. They start playing but realize that all the money is missing. So, instead they each get a piece of paper and start writing. 1. Bank pays Bob $50 2. Eve pays Bob $10 3. Alice pays bank $20 4. Alice pays Eve $30 5. Bank pays Bob $20 Every time someone pays anyone anything, everyone writes the transaction down, and makes sure that the transaction is valid. If the transaction is invalid (Someone notices that Bob is trying to spend more money then they have) then they won't accept the transaction into the ledger. Because everyone is paying attention to what you're spending, and everyone can calculate exactly how much money you're supposed to own, nobody can cheat by spending the same money twice. If you try someone will point out \"Hey! You already spent that money paying the bank!\". This isn't really feasibly for DRM in the current form, because it's a solution to a different problem entirely."
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7o6x6l | Why are car batteries 12 volts instead of 9 or 5? | Technology | explainlikeimfive | {
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"back in the early days they used to be 6v. then 6v wasn't enough to run the electric starter. so they doubled up and went to 12v. there was alot of talk about 10 years ago to go to 24v to help with auto-stop-start systems for saving fuel during traffic. but now with full on electrics and hybrid car's starter-generator, that's basically a dead horse."
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7o7azd | What is a paperclip maximizer and what is the point of it? Is it possible in real life? | Im very confused/lost. Also does it have anything to do with quantum computing? | Technology | explainlikeimfive | {
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"A [paperclip maximizer]( URL_1 ) is a thought experiment about how dangerous a true AI can be if its goals are not carefully constructed. It goes like this: an AI is created whose only goal is to make more paperclips. It does obvious things like obtaining more wire, constructing new factories, hiring people, etc. But it also works on increasing its own intelligence and capacity so that it can do those other things better, since that falls under the heading of \"make more paperclips.\" If it has no other constraints, it will eventually (theoretically very quickly) enslave the universe in order that all might become paperclips. To answer your questions: the point of a paperclip maximizer is to be an object lesson on the pitfalls of designing AI. Many people believe it to be possible, but no one is actually designing one, and there are no true AIs yet - that we know of. It has almost nothing to do with quantum computing. Finally, here's a fun little clicker game about paperclip maximization: URL_0"
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7o8ncn | What makes gasoline so special that it can power engines and why is it so difficult to find an alternative fuel source? | Technology | explainlikeimfive | {
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"it's flammable, high energy output, easy to transport, and stays liquid in decently wide variety of temperatures. lots of things can power an internal combustion engine. diesel, peanut oil, alcohol to name a few.",
"So, I'm just going to throw this out...gasoline is a specific refinery blend. Many engines/turbines (the important ones) are run on diesel fuel, natural gas, etc. Your car runs on gasoline for some specific reasons, but that 16,000 hp engine at the municipal power plant runs on diesel fuel. But for a vehicle you want energy density, safety, and quick refueling. For a car, liquid petroleum distillates were discovered early and are great. You can fill up in 3 minutes. They aren't that dangerous. They are a liquid of almost entirely hydrogen-carbon bonds, pretty good energy density. Lots of alternatives are thrown about. Hydrogen...hard to store, needs extreme compression for energy density, etc. Plug in hybrid...heavy batteries with limited lifespan. Compressed air (yes, every 5-10 years we get a stupid fucking story about Tata making a compressed air car) just unworkable. Edit: This may have sounded negative, I'm a huge fan of alternative fuels and actually work in the environmental industry. It's just that nothing available is as good as gasoline as a general fuel, and there is nothing on the radar which will be. Yes, a Tesla will blow a comparable gas vehicle off the line in a 1/8 mile, but that doesn't mean it's fully ready for a family that makes $50,000/year.",
"Gasoline has a high energy density. Everything else requires larger tanks or more weight for the same amount of power. And gasoline is remarkably stable in liquid form, so it's pretty safe as a fuel. It's cheap. Lastly, there's a lot of infrastructure built for transporting gasoline. Hydrogen is none of these. Biofuels are are a lot closer to gasoline, but right now, making it eats up arable land and competes with food production, but would be carbon neutral. Batteries are getting better, and a few more generations of incremental improvements will make make using them a more practical choice.",
"Abundance. It’s relatively simple to build combustion engines that run on rubbing alcohol. But the consumption of gasoline is just shy of a billion gallons a day globally. The annual alcohol production globally is somewhere around 20 billion gallons a year. There’s simply SO much more fossil fuels available and production is so high compared to other fuel choices. It’s possible to convert a combustion engine to run on any liquid or gas that is flammable. Some work better then others but there isn’t one which is as abundant and convenient. (Natural gas is close)",
"Two words: Energy density. ELI5: Gasoline contains more energy per mass (per lb/kg/whatever weight measurement) than any other fuel alternative. This means that, per tank of fuel, you can go father that on just about any other fuel source commonly found on Earth. Why energy dense? Because of the number of bonds in the hydrocarbons that makeup gasoline that are broken by combustion, releasing energy. Why so difficult to find an alternative fuel source? Well, oil occurs naturally - so it's relatively easy and cheap to obtain. Gasoline is distilled from oil - in a relatively straightforward manner. In short, it's relatively easy to obtain gasoline from oil and oil is still relatively easy to pump out of the ground. No other fuel source is as easily obtainable on Earth. Most other fuel sources are either not as energy dense (natural gas) or take as much/more energy to synthesize than you get from burning it in a car engine (making it economically non-viable).",
"Everyone is talking about energy density, which is true, but I think it is interesting to think about why this is. The energy in petroleum originally came from the sun. It is mostly made of ancient plants or animals that ate plants. Plants have the ability to store energy from the sun in their cells. The important aspect to this is that a single plant can only get very tiny amount of energy per day from the sun. This is why most plants do not move like animals or have many of the complex systems that animals do. They can't get energy fast enough for that. Animals get around this by eating a *ton* of plants so they get the energy benefits of of large amount of solar collecting plants in one day. Petroleum is made of millions of years of plant (and animal) material with all that stored energy accumulating layer after layer under tremendous pressure underground until it compresses into oil. If you think of plants as little batteries with solar panels, petroleum is made of zillions of them compressed into a kind of super battery with a LOT of energy packed into a small place. And because it is underground it is cheap to get. Man-made solar panels have the same issue plants do. They can only get energy at a certain, slow rate. You can't run your car just on the energy you would get from covering it with solar panels or windmills. There literally isn't enough energy coming in fast enough. Fossil fuels allow us to *cheat* by using up millions of years of solar accumulation at once. It will work until we run out of course. It is hard to beat millions of years of accumulation free for the taking underground. Hydrogen is great at storing energy but it isn't just lying around. We have to extract it from other compounds which takes more energy than you get out!",
"The Energy stored in a gas tank is massive, 10 times larger than in the same weight of TNT. Let that sink in - your car's tank is equivalent to 300kg bomb. That's the amount of explosive in WW2 naval torpedo, roughly, enough to sink a battleship. However, petrol is safe because it needs to be thoroughly mixed with air before it can burn. It actually uses 15 times more air than petrol during combustion (which doesn't have to be carried around in the tank, increasing its performance). This applies to most of the hydrocarbon-based fuels, be it petrol, diesel, liquid gas, alcohol, kerosene. They are all pretty much the same in their elemental composition of carbon-hydrogen-oxygen. Even the fat you store around your waist, your own fuel tank, is pretty much the same as petrol, both in elements and energy density. Petrol also remains liquid and stable in a huge range of temperatures, covering all but the worst of Earth's climate. Batteries do not have this safety feature. If they short all that stored energy comes out in a hurry. Right now they have about 1% energy density of petrol and we are constantly fed news about batteries bursting with fire and causing harm. When batteries catch up with petrol in energy density they will become ticking bombs waiting for any malfunction to go off. The future lies not in batteries but in using green energy sources (solar, wind, nuclear) to produce synthetic hydrocarbons, using CO2 from atmosphere and water. Literally reversing the chemical processes that burn petrol in engines. Plants do it already but they aren't efficient enough to catch up with our energy demands."
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7o912k | How do scientists know what's inside the Earth? | Just read an article about scientists drilling to the Earth's mantle for the first time. There's the crust, the mantle, then the outer and inner core. But how do they know these layers are there? How do they know the exact depth of the mantle below the sea floor? How do they know the core is so hot? What data are/were used to draw these conclusions. | Technology | explainlikeimfive | {
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"I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do we know what the earths inner consists of, when the deepest we have burrowed is 12 km? ]( URL_7 ) ^(_ > 100 comments_) 1. [ELI5: How do we know what the inside of the Earth consists of? We have never seen it or been there ]( URL_9 ) ^(_5 comments_) 1. [How do we actually know what's inside the earth? (Mantle, core) ]( URL_2 ) ^(_12 comments_) 1. [ELI5: How do we know how thick the Earths crust is? ]( URL_3 ) ^(_3 comments_) 1. [ELI5: How do we know what the centre of the earth is made of? ]( URL_4 ) ^(_6 comments_) 1. [ELI5:How do we know how hot the core of the Earth is and everything underground if the farthest we have dug a hole is just 8 miles? ]( URL_8 ) ^(_._) 1. [ELI5: How do we know the earth's mantle is 70km beneath the crust of the furthest we've been able to drill is 12km? ]( URL_6 ) ^(_9 comments_) 1. [ELI5: How do we know so much about the Earth's 'insides', like the crust, mantle, etc.? We know so much, like the thickness and the composition of these layers of the Earth, but I don't understand how we could ever figure this out. ]( URL_0 ) ^(_6 comments_) 1. [ELI5: How do we know that Earth's core exists and is made of iron when we are barely able to get significant data from just the inner crust? ]( URL_5 ) ^(_4 comments_) 1. [ELI5: How deep can we \"look\" into the earth, and how can we know exactly what it is made of? ]( URL_1 ) ^(_15 comments_)",
"It's mostly seismography. Basically, different materials resist vibrations to different degrees, so when earthquakes happen we can measure how long it takes to get from point A on one side of the planet to point B on the other side, with point C forming a triangle. If we gather data from all three sites, we can determine fairly accurately what lies between them based on how long the vibrations take to reach each point, and how weak the vibrations are when they arrive. Because earthquakes happen **very frequently**, we've collected a whole lot of data on this. We've been able to determine that the Earth is definitely not hollow, that the center is probably a mass of iron-nickel alloy (inner core) surrounded by molten rock and iron-nickel-sulfur alloys (outer core), and that there are definite differences between the composition of each layer."
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"https://www.reddit.com/r/explainlikeimfive/comments/2cuf7l/eli5_how_do_we_know_so_much_about_the_earths/",
"https://www.reddit.com/r/explainlikeimfive/comments/3pqymk/eli5_how_deep_can_we_look_into_the_earth_and_how/",
"https://www.reddit.com/r/NoStupidQuestions/comments/38fpmr/how_do_we_actually_know_whats_inside_the_earth/",
"https://www.reddit.com/r/explainlikeimfive/comments/33y3ht/eli5_how_do_we_know_how_thick_the_earths_crust_is/",
"https://www.reddit.com/r/explainlikeimfive/comments/44beew/eli5_how_do_we_know_what_the_centre_of_the_earth/",
"https://www.reddit.com/r/explainlikeimfive/comments/2h3vwh/eli5_how_do_we_know_that_earths_core_exists_and/",
"https://www.reddit.com/r/explainlikeimfive/comments/2yqq68/eli5_how_do_we_know_the_earths_mantle_is_70km/",
"https://www.reddit.com/r/explainlikeimfive/comments/4mjpkm/eli5_how_do_we_know_what_the_earths_inner/",
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7o9m77 | Why can't the security bug with computer processors be fixed by just not running the kernel on the same processor core as other programs? | Technology | explainlikeimfive | {
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"because the memory is still shared. each core has local cache that's tiny, and then a larger shared l2 and l3. and each core can also snoop into the cache of other cores too. so even if one core is running it, the memory is not isolated."
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7oac2s | The reason for the difference in quality between a still frame taken from a video shot in 1080p, and a 1920x1080 resolution photograph | Technology | explainlikeimfive | {
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"Generally a movie frame will be much more highly compressed than a still frame, i.e., the average number of bytes used for a movie frame will be less than for a still frame of the same size. Movies just can't usually afford the number of bytes. Movies do have one advantage over stills in that consecutive frames will generally be very similar. Movie compression is heavily based on this so that most frames are encoded by saying \"this frame is exactly the same as an earlier and/or later frame except ...\" and then giving a list of differences. This means that movies can (on average) achieve the same quality with many fewer bytes. Nevertheless, movie stills will generally be of lower quality than a photographic still. Of course there are exceptions. There are plenty of over-compressed 1920 & times;1080 JPEG images out there of poorer quality than typical, high-bitrate blu-ray frames.",
"In addition to the video compression that jaa101 already mentioned, video frames often have motion blur because the camera and subject don't stay still relative to each other. Still photos can have motion blur too, and it's sometimes used deliberately as an effect, but more commonly a still photographer will reject the blurry shots in favor of sharper ones."
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7ocz68 | Why do emojis look different across platforms and why do they look especially bad in web browsers? | Technology | explainlikeimfive | {
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"Emojis are Unicode characters just like the letters and numbers in the text around them. Character number 65 is \"Latin capital letter A\", and number 128512 is \"Grinning face\". When I type 😀, your device just gets that number, and it's up to your device to provide a font with a symbol to represent the character."
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7odztq | If lie detectors (polygraph) are a pseudo science the why are they still used in court cases and by law enforcement? | Technology | explainlikeimfive | {
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"They are still used for their original purpose: to intimidate witnesses into telling the truth, because they think the machine works.",
"Courts: In many courts they are not permitted. This is true in the U.S. It's not so much that they \"don't work\" as they are not reliable enough to constitute \"evidence\". _____________________________________ Law Enforcement: Many people don't know that they are unreliable. So they are used to \"raise the stakes\" on a suspect being questioned. They are more likely to answer truthfully if they believe their lies will be identified by the machine. They can also use it to question your answer: * Was Steve there with you? * No. * < Looks at polygraph analyst > * < Analyst shakes his head disapprovingly > * Are you sure? Because if you lie to us that's falsifying information? I'll ask one more time, was Steve there with you? * I don't know, I think I saw him, yeah I must have. Yes. And human memory is a funny thing. You never remember events. you remember the last time you remembered that event. And each time it may distort just a little bit. Also it's used in hiring decisions. \"We don't have a good reason to deny this candidate but he's giving off bad vibes. Let's just say we didn't like his polygraph.\"",
"They aren't universally accepted in courts (which courts? There are lots of courts in the world, and even in a single country like the US, there can be a wide variety of laws and accepted applications), or universally used by law enforcement. However, even If you accept that they don't work, not everyone is aware of this, and they can serve (as an example), as a useful bluff in interrogation. A nervous criminal is not necessarily a good liar. A fearful one may not stick to a story.",
"They aren’t typically used in criminal cases, because they are not effective. They are still popular during the hiring process for government and law enforcement jobs but it’s more so to trick applicants into not sticking to their story, catch them in inconsistencies and lies. Understanding and preparing for the test can be more effective than telling the truth.",
"They're typically not admissible in court (at least in Canada and the US), as it is up to the trier of fact (e.g. the judge or jury) to ultimately decide whether a person is telling the truth.",
"Not used in court. Never talk to police without an attorney. They lie too much. Too often.",
"I had to take a polygraph as part of my security clearance investigation, that was an incredibly hokey experience.",
"The lie detector results themselves are generally not admissible. However, after the polygraph is administered, the questioner will review the results with the individual. “When I asked this question, your response indicated deception, why is that?” The follow on questions to the polygraph are what is useful.",
"They very much function on actual hard scientific principles. The problem comes from the fact that even then, the human mind is still able to fool itself and subsequently the detector, which renders its reliability entirely subjective. From a court perspective, the Supreme Court has ruled that it is up to each individual judge to determine whether polygraph results are admissible as evidence or not. From a law enforcement perspective, it can be used as a tool to confess guilt or drive them to accept a plea bargain. You'd really have to have a psychological evaluation done of the suspect in conjunction with the polygraph test to really determine if the polygraph is providing useful/reliable information or not based on the suspect's answers.",
"I took a voice stress analyzer test. The examiner was really cool and explained how the test worked. He believed it was effective. I told two lies on purpose as part of the test and the program picked it up. Just my two cents.",
"In the US (and UK, I believe) it's not normally admissible in court, with exceptions for some states and situations. However, in some places, it is used as an intimidation tactic because the people being put under the test believe the test will work, even if it's really only recording nervousness. The tester will also deliberately create a very interrogation-like atmosphere when the test is conducted to add to this effect."
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7oeks3 | the difference between saving a file as a.pdf and printing to a .pdf | To be more specific - when you save a file many programs give you the option of saving as the pdf file type. However you can also use the print option and select "save as pdf" as your printer, which also produces a pdf file. | Technology | explainlikeimfive | {
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"When you \"print as\" a .pdf, you typically get more options regarding the final product (as in, if it will be color or greyscale, what the final quality will be like, etc.) that you don't get by just saving it as a .pdf. Alsoooo... I believe the feature of saving something as a .pdf is a relatively young one. Versions of Office older than 2010 required at least a plug-in to let you save it as a .pdf file. \"Printing to .pdf\" also required third party software typically, but I feel like that was more commonly available than the Office plug-in for some reason.",
"The short ELI5 answer is: There's not necessarily any difference at all. They are merely two different names for taking a source and turning it into a PDF file. However some programs might opt to create a \"dumb paper\" when you choose to print (because that's what you would physically print) whereas saving as PDF lets you add lots of metadata, encryption, and so on. This is probably the philosophically correct way to do it, but there's no guarantee this is the case. For instance I have a program which when selecting print will create a PDF containing an image of the source, even if the source is text."
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7ofv98 | How do contactless cards generate their RFiD signal? | Surely there needs to be a source of energy to generate this signal but how come I don't need to charge my card | Technology | explainlikeimfive | {
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"The reader hits it with a pulse which gives it enough energy to send a response with, this makes the bases big and lets the tags be tiny. Its a combination of wireless communication and wireless charging"
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7og34l | How is natural gas used for air conditioning? | The title is fairly self explanatory. I currently have a school project in which I need to design a way of reducing our schools natural gas usage. In the school data showing how many cubic meters of natural gas are used, the summer months use a fair amount. When I asked my teacher why she said I could assume it was because of air conditioning? What I want to know is how natural gas is used for air conditioning? | Technology | explainlikeimfive | {
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"It works like a normal air conditioner, the only difference is the engine used to circulate the coolant burns natural gas instead of electricity, usually more practical for large commercial spaces."
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7ohyb5 | The advantages of music on vinyl when production is all done on digital systems these days. | Technology | explainlikeimfive | {
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"text": [
"\"Doesn't digital production make the theoretical \"benefits\" of vinyl's analog nature rather moot?\" Yes. I thought the vinyl fans were seeking older pressings from the analog days?"
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7okist | How do theft detectors in shops know you've bought the item? Is it to do with scanning the barcode, or is there something else that gets scanned? | Technology | explainlikeimfive | {
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"Most theft detectors rely on one of two mechanisms. Small tags and large tags. Large tags get removed by the cashier, and are either attached in a way that damages the item if you try and force it open or locked in a larger and more cumbersome package. Small tags are usually small magnetic stickers, and are demagnetized during the checkout process. You may see in some stores that there is a large circle on the counter that the clerk slides everything across. That's for small tags. With the tags demagnetized, you can pass through the theft detectors without setting off alarms.",
"There are a few methods, I'll describe one of the more common ones. The item being protected has a small circuit in it, about the size and shape of a postage stamp. It is essentially a radio receiver, and when a certain frequency is applied to it, it emits an echo that can be detected. That's how the alarm part works. When that same radio frequency is applied with high intensity the circuit becomes overloaded and shorts out, permanently damaging it so it no longer echoes. That's how the deactivation works.",
"They have those sensors at the doors and security tags on items. When you checkout they remove or disable the security tag. So when you walk out the alarm doesn’t sound."
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7olag9 | why do games have loading screens? | Technology | explainlikeimfive | {
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"It's so the user can tell that the game is loading. If you just display a blank screen until the game is fully loaded, the user might assume that something isn't working and restart the program.",
"The load screen is there so that the program has time to load up libraries, bins, functions, etc. before launching the playable portion of the game. The load screen was put in so that when you hit start you didn't go to a black screen and wait for the game to load, because if it takes long enough the user might think the program had crashed. What is displayed on the load screen on the other hand is entirely up to the program developer, so if they choose to they could just show a black screen, but most choose to either show images of the game or load progress bars.",
"Okay. Imagine that playing a game is like asking your friend to give you directions when driving. You ask your friend what you should do next, and your friend tells you to go north, or take a left turn, or make a u-turn at the third light. The thing is that your friend doesn't know how to drive everywhere, and if you go to a place that he's unfamiliar with, he's going to have to stop and check a map every time, and that would be annoying. You might have to pull over and wait everytime as they look up the map and figure out what route to take. But if you give your friend time to study the route ahead of time, you tell him where you want to go and he has the time to look at the map and figure out what directions to give, there would be far less interruptions and the whole experience would be much more pleasant. The same basic concept is there for many video games. The game needs to prepare a level, have all the parts of it ready ahead of time, so that when you play the game you don't need to stop and wait for each part of the level to be prepared. You can explore the whole level without taking breaks, because the game had time to prepare ahead of time. Many games have complicated level designs with lots of graphical detail. It takes time for the computer running that game (which could be a console or a phone!) to get those levels ready, and so a loading screen gives the game time to prepare."
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7olcv8 | How are electric cars heated? | Technology | explainlikeimfive | {
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"Yeah, you're completely correct. There's just heaters and they do cut into the battery life of the car a fair deal."
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7omiqb | What's the difference between 4WD and AWD? | Technology | explainlikeimfive | {
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"All 4WD vehicles are \"temporary\" in that the 4WD modes must be engaged and disengaged manually. Moreover, they should not be used all the time, only when necessary. A 4WD vehicle is otherwise identical to a 2WD vehicle save for the addition of an auxiliary gearbox and differential on the secondary drive axle. The auxiliary gearbox, also known as the power transfer case, allows the secondary drive axle to be mechanically coupled and decoupled from the power train. When it is coupled, both drive axles receive the exact same torque and as a result all four wheels rotate at the same angular velocity. When this is not possible (such as when making a tight turn, or going over dry pavement) the slower moving wheel will end up spinning; in worst case scenarios, the powertrain may be damaged. The power transfer case may also contain an additional reducing gear which can be engaged to increase the engine:wheel gear ratio higher than that provided by the first gear. This provides very high torque to the wheels and can only be used at low speeds, such as for climbing out of a ditch or towing a trailer up a slipper slope. AWD on the other hand provides power to all of the wheels, all of the time. The key difference between AWD and 4WD is that AWD vehicles have a mid-differential rather than a power transfer case. The mid differential allows both drive axles to spin at different rates, and is often electronically controlled to shift torque around as needed in order to maintain traction."
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7oq74g | How do solar cells actually work? | Technology | explainlikeimfive | {
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"Ok, here is a very rough explanation, assuming you know what atoms and electrons are: Solar cells consist of a semiconductor, for example silicon. There are two zones in the cell, one is positively charged and one is negatively charged (due to a process called doping, which means bringing atoms of other elements into the silicon). Semiconductors normally do not really conduct electrons, like metals do, only if the electrons have additional energy. Where does that energy come from? From the light (often \"photons\" are mentioned here, which are light-particles, but that is another topic). So the light hits the semiconductor, gives an electron additional energy so it now can move freely. At the place where the electron used to be is now a hole (positively charged, as the electron is negative). The hole can also \"move\" when an electron from a neighbouring atom jumps into the hole - from a point of view the hole has moved to the other atom. So the hole moves to the negative zone and the electron moves to the positive zone, from where it moves further through an electrode and cables and your lamp or motor or whatever you want to power, and finally fills the hole on the other side of the cell.",
"Charges come in discreet packets - electrons and protons. Atoms have a set number of electrons to match their protons. However, because of quantum effects and interactions between charges, they can actually \"hold\" slightly more or fewer of electrons, depending on the element. The difference can be enough to produce current - that's how batteries work. In the quantum world, 1 + 1 does not equal 2. 2 electrons together produce a slightly different charge than 2 electrons separately. When you pack 14 of them together in a silicon atom, weird things happen. Now, solar cells have 2 materials with different electron potentials. Electrons would like to travel from one material to the other because there is a slight difference in their electric charges. However, that difference is not large enough to actually break any electron free from its atom. When a high energy photon from the sun strikes it frees a single electron from its atom. That electron is now free to travel to the other side of the cell and produces a current when it does."
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7or8xv | nano tubes/nanotechnology in products today | When I hear that companies have/are using nanotechnology in their products, whether that is anything from clothing to super cars, I always think of miniscule robots like movies lead me to believe. So are we living in the future where we actually have quote-unquote robots that can move around and repair damage and replicate and that? Or is this just some kind of new glue or something that marketers are just spouting? | Technology | explainlikeimfive | {
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"Nano- refers to whole things which are smaller than fractions of a millimeter, or making materials with properties on the scale of nanometers. For example, a robot that's only 0.1mm (100 microns) wide. (A sheet of paper is about that thick.) Manufacturing of individual parts smaller than mm size is possible, although kind of expensive. Clockwork Watch parts and the components inside modern computer memory and processors for example. However, making a whole robot at this scale is very difficult to do. There fact that it can't be done with mass manufacturing (yet) is why it seems obscure. Nano-construction can also refer to materials with special properties at the nano- level. (Millionths of a millimeter, ~0.001 microns). Carbon nanotubes and fullerenes (molecular carbon hexagon sheets) are examples of this. Again, the main reason that makes these technologies obscure is they're really difficult and expensive to make, so they're not part of our lives much. But these are problems chemical and manufacturing engineers are working hard on, and big companies are investing money into because there's lots of great, useful, and profitable, technologies to be found if we can get it working."
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7osqsz | How they shoot films for different formats such as standard, 4:3, 3D, and IMAX | I've always imagined three cameras being used to save time in post (see my comment). | Technology | explainlikeimfive | {
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"[This]( URL_0 ) is what I've always imagined.",
"The answer will vary from project to project. Contrary to some of the answers you'll see here, contemporary movies use mixed formats, a practice that has become much easier and more commonplace since the advent of digital post-production. Even indies will sometimes mix camera systems based on what's convenient. And the post process for movies is monstrously complicated. If you take a look at something like The Dark Knight, you'll find that the finished film is actually a combination of three film formats: 65mm IMAX, 35mm anamorphic, and 35mm VistaVision. Or, to cite another superhero blockbuster, there's Captain America: Civil War, which uses three different digital camera systems: 2.8K Arri Alexa, which is the current industry standard camera; the 6.5K Alexa 65, which is a \"large format\" system meant for IMAX; and the 6K Red Epic. Regardless of whether you see these movies in the regular theater, on IMAX, or at home, the footage is the same, even though it's a combination of different formats. So the question that matters is: What format will the movie be FINISHED in? What aspect ratio will most of your viewers see the film in? Let's imagine Movie X, a Hollywood blockbuster with lots of IMAX footage. Most of Movie X's audience isn't going to see it on an IMAX screen, so instead all of the footage is framed \"safe\" for 2.39 wide screen, meaning that the essential action is kept to a narrower part of the middle. The monitors used by the director and crew of Movie X will have frame guides to help them; this is pretty standard, as the actual aspect ratios that film and digital formats RECORD in don't correspond to the formats we use to watch movies. (For instance, the raw footage of a film in the 2.39 widescreen aspect ratio will be in 1.78, 2.0, 2.66, etc., etc; 1.85 is shot in 1.78, 1.37, and so on.) Here's what director's monitors look like: URL_0 The shot is of David Fincher on the set of the Girl with the Dragon Tattoo, a film that was shot in 5K in a 2.0 aspect ratio and finished in 4K with a 2.39 aspect ratio; you can see the red box that shows the director the final frame relative to what's coming through the monitors. But back to Movie X. While the IMAX prints of Movie X will show the entire, uncropped IMAX frame in the IMAX shots, the digital copies released to regular theaters will have the top and bottom cropped off the same shots; for a home video release, they might be cropped a little less. On home video and in digital theaters, the footage will blend together almost seamlessly, though the IMAX stuff will have its unique qualities. (For instance, IMAX requires the use of much longer lenses, which creates a different sense of space.) In IMAX, the IMAX footage will look great and everything else will look grainier and murkier in comparison. As for 3D: If you're ACTUALLY shooting in 3D, you just flatten it into a 2D image. However, 3D cameras (which use two sensors and two lenses mounted side by side) are notoriously difficult to deal with, and most modern 3D releases are actually \"converted\" to 3D in post. In other words, it's just a fake effect made by computer-assisted guesswork about the distances between objects in a flat frame."
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7outvx | What exactly is a commercial pilot doing in the cockpit during a flight? So many buttons, pedals, paperwork etc? | Technology | explainlikeimfive | {
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"Over twenty years experience, currently flying a 737. All the buttons and switches are basically used for lights, power, pumps and engine start up procedures. Take off and landing are basically the only time I'm controlling the aircraft by hand. There is paperwork sometimes I'm evaluating a first officer, other times just chatting. There is no sleeping on the flight deck, there has to be two pilots awake at all times. Long hauls have more than two pilots onboard so they can rotate sleep.",
"Chilling most of the time really. Most of those buttons aren't particularly useful most of the time and aside from takeoff and landing, they don't do much. The plane basically flies itself, you don't touch any of the controls and the thing keeps moving forward in flight and especially with modern autopilot being able to change its trajectory, the pilot is mainly there to supervise and call the shots in case anything needs to be changed, say if turbulence requires the flight to elevate or descend. This is actually a bit of a problem, pilots fall asleep during flight as a result, this is surprisingly normal on international flights as they tend to be long and that is partially why two pilots are there, but on occasion both fall asleep.",
"there's numerous points durign the takeoff and landing. during the cruise legs, there's really nothing much going on. they're watching the front facing weather radar, keeping tabs on the radio, drinking coffee. and on international flights, taking naps.",
"56% admit to sleeping 33% admit to sleeping and waking up to find the other pilot sleeping as well URL_0",
"I had a cousin who was a pilot of private passengers style jets for 30 years. He flew primarily for one rich guy only, who made deals and had business all over the US. The longer flights, and on the primary company plane he knew well, he said he slept a good bit. Interestingly enough, his last piloted flight was nearly his last. He was coming into Chicago flight control zone and awoke with a stinging headache. He couldn't identify where he was, or grasp what was going on for a few minutes. He apparently had blood vessel pop in his head, and couldn't reason for a few moments. He found he had turned off the Auto Pilot and was circling back when he finally got it together. He had the approach map out and finally put it together, and landed. I think he notified air traffic he needed a straight landing or such, and set it down. The doctors straightened up what happened in his brain over the following year, but he was close to retirement age and quit rather than go through all the requalification."
],
"score": [
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"https://uk.reuters.com/article/oukoe-uk-britain-pilots-sleep/half-of-british-pilots-admit-to-falling-asleep-in-cockpit-survey-idUKBRE98Q0L620131009"
],
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|
7owgtj | What is cloud mining? | Technology | explainlikeimfive | {
"a_id": [
"dscsvvp"
],
"text": [
"Cryptocurrency 'mining' is using computer power to perform work that helps run the cryptocurrency. To reward people for doing this work, a small percentage of the time work will result in a worker being given some of that currency. Trying to make money this way is called \"mining.\" Cloud mining is like cloud computing. You pay someone else to do work on your behalf. You get any cryptocurrency generated by that work, and they get paid to do the mining for you."
],
"score": [
10
],
"text_urls": [
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|
7owjmr | How a ship find the radio frequency of another ship | For example, the navy or cost guard is chasing a ilegal fishing o pirate boat. how they find the radio frequency of the radios in that boat ? if that ship is illegal or is not register how they do that. | Technology | explainlikeimfive | {
"a_id": [
"dsct60z",
"dsd0eu7"
],
"text": [
"Normally if you are being intercepted by an aircraft they will transmit on the \"guard\" frequency which is a frequency dedicated to only emergencies. Most maritime and airborne radios are actually 2 radios in one. One radio with an adjustable frequency selector and one that's always tuned to the guard frequency.",
"You usually hail over international VHF frequency Ch 16, or the HF distress frequency 2182 kHz which dependent on size of ship is a legal requirement to set listening watch on. If you're still intent on boarding and they don't answer, you launch a boat with boarding team and/or launch a helicopter above them, and hail them using a loudhailer."
],
"score": [
10,
3
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"text_urls": [
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} | [
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7oxd3v | the mess of weird text you get when you turn a .png/.jpg file into a .txt | Technology | explainlikeimfive | {
"a_id": [
"dscy9lf",
"dscy9i3"
],
"text": [
"In the end, all files are just 1s and 0s. A jpg is only a jpg because the program opening it knows how to interpret those 1s and 0s as an image. But notepad doesn't know how to interpret it as an image. It just assumes anything you open in it is meant to be text. So it interprets the data as if it was text. But since the data wasn't meant to be text it looks weird. There are some characters that have special purposes and aren't really meant to be displayed. So they are represented by weird symbols. Chances are some of the numbers in that jpg file will happen to match up with the values of these special characters so you get these symbols which you wouldn't normally see in data that is actually meant to be text.",
"Every file on a computer is just a stream of numbers. While many file formats, like PNG & JPEG, have strict formats so you can't even open an arbitrary chunk of data, a text file does not. A text file is just a file containing text. If you try to open some other file as a text file, the text editor will carry on as if the numbers in the file represent text characters based on an encoding like [ASCII]( URL_0 ) or UTF-8. Since ASCII includes a bunch of garbage characters & stuff like \"new line\", you end up with meaningless garbage."
],
"score": [
17,
5
],
"text_urls": [
[],
[
"http://www.asciitable.com/"
]
]
} | [
"url"
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"url"
] |
|
7oy32z | the effects of watts, amps and volts on charging speed | Phone chargers and the like will state their voltage and amps on them somewhere like 9v/1.5a. What effect does increasing volts and decreasing amps have and how does wattage fit into it? | Technology | explainlikeimfive | {
"a_id": [
"dsd3dev"
],
"text": [
"In the end, more watts means faster charging Unfortunately you're trying to charge through a long skinny cable, this cable is pretty limited on how much current it can handle. Try to push too much current through it and you'll lose your watts to heating the cable instead of filling the battery Increasing the voltage allows us to decrease the current and maintain the same output wattage, hopefully increasing the power that makes it to the phone; but a lot of chargers have higher voltage and higher current to give you higher output wattage and higher delivered wattage. A 5V 2A charger is only outputting 10W of power, but a 9V 2A charger is outputting 18W and can charge about 80% faster USB Power Delivery now supports up to 20V with 5A providing 100W of power(on special cables) which lets it charge 40x faster than a basic USB 2.0 charger at just 5V and 0.5A"
],
"score": [
3
],
"text_urls": [
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} | [
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7ozs3d | How does oversampling work? | I just don't got it. I'm talking about oversampling on a screen. Let's suppose I have a full HD screen. That means 1080*1920 pixels. When a game purposes to display the image with oversampling, how does it work? My screen still has the same amount of pixels doesn't it? How can it displays a more detailed picture? | Technology | explainlikeimfive | {
"a_id": [
"dsdhy8y",
"dsdjj99"
],
"text": [
"What is the benefit of oversampling? You get a cleaner image for edges, color gradients and transparency. If you calculate the imagine in a higher resolution first, that imagine contains more *information* about what is going on on the screen in comparison to the lower resolution. So if you get a FullHD image you get just 1920*1080 pixels, let us assume you calculate a scene in a dark hut in shadows and a fire that throws sparks. Now take some pixel that there is SHADOWY_BACKGROUND and the next pixel to it is RED_FLAME. So you get a sharp transition, a jump from BLACK to RED between the shadow pixels to the left - they are all very dark grey - and the next one, that is a bright red spark. It clearly is discernable as a black surface next to a red block, especially considering the again next pixel is also the same (or very similar) red. Now you do a oversampling in 4K (this is a good example, as you get exactly twice as many pixels in each dimension): The same transition from the dark shadow to the flame might not be as clear cut. You have a dark shadow, the next pixel is a shade of red, the next one brighter, the comes the red pixel. You have the same scene, but with more information, more details about all color gradients, all transparencies, and all edges. If the oversampled image is downsampled, it is not just done by discarding, for example, every second pixel, but the image is processed in way that pixels next to each other are averaged. So instead of BLACK BLACK RED you'd now get BLACK DEEP_SHADE_RED RED in the FullHD image, which means your oversampled FullHD image is cleaner regarding *all* color gradients that are next to each other than a native FullHD would have been. In this way, oversampling works like a full-screen all-details anti-aliasing. Just with the difference that it works with internally more details that the native resolution would provide. Normal anti-aliasing basically works by blurring the image in smart ways, oversampling works with more details and then uses that to average near pixels instead of just \"blurring around\".",
"Here's my ELI5 version of what /u/TheRealStardragon said: If you draw a black circle on a white screen the first simple version will be ugly and jagged. Even though the circle is supposed to be black it will look much better if you put some gray pixels in those jagged corners to smooth the transition from black to white. This is called anti-aliasing and there are mathematical formulas to figure out exactly what color pixels to put where, but they are very complicated. If you have extra memory you can avoid the mathematical complications by super-sampling. Just have the game engine generate the image in 4K. Then down-sample it to 1080P. In the final 1080P image that is displayed every pixel is the average of 4 pixels from the 4K version. So the little white spaces in between the jagged black corners of our circle end up the appropriate shades of gray without a bunch of complicated math."
],
"score": [
15,
7
],
"text_urls": [
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} | [
"url"
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7p0scc | How can 3 CPU's made by 3 separate companies have the exact same security flaws? | Technology | explainlikeimfive | {
"a_id": [
"dsdmuly"
],
"text": [
"A CPU is a list of instructions. By necessity, they all have to run the same instructions no matter who makes it, otherwise every piece of software would have to have multiple versions based on what CPU is in the machine (just like they have to have multiple versions for PC, Mac, Sparc, etc). Imagine there are 3 companies in town who can put a swimming pool in the ground in your back yard. They're all going to dig a hole, pour in concrete, maybe they tile some of it, and they're going to fill it with water. If all 3 companies use the same concrete mixture, it's possible that all 3 companies have pools that crack easily, for example."
],
"score": [
3
],
"text_urls": [
[]
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} | [
"url"
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|
7p1qn4 | Why are some websites browser specific, if their underlying code is based on a standardization, supported by most browsers (Google Earth on FF)? | Technology | explainlikeimfive | {
"a_id": [
"dsdufnf"
],
"text": [
"There are some specific tags that only specific browsers understand, there was a fair amount of Internet Explorer specific HTML and CSS years ago that wasn't part of the standard but IE implemented it. Other times you're relying on different implementations having different quirks, you made your page work with IE which uses a slightly off standard look and now it doesn't work with Firefox which uses a slightly different off standard way Now you're likely to run into things like ActiveX that need Internet Explorer to be able to run because its coupled tightly with windows. Its rather uncommon to find something that works in Firefox that doesn't work in Chrome. Google stuff generally works with every browser(can't risk losing customers!)"
],
"score": [
3
],
"text_urls": [
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} | [
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