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cp90pq | How do radio stations gauge their audience numbers if radio is a one way broadcast? | Technology | explainlikeimfive | {
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"It depends on the region. Different countries / regions use different methods, but by and large, most methods are just different types of surveys. Where I live, radio audience measurements rely on surveys with a sample size of a few hundred people. These people in the sample group are expected to maintain a paper log of their radio listening behaviour (what time they tuned in, which station they listed to, when they changed stations, etc). This data is then extrapolated to the entire population, which is why the ratings are absolutely ridiculous and most of the time, useless. Similar methods are used for TV audience measurements too, except that with TV, some measurement systems use devices attached to the TV that can log when the TV is on, when channels are changed, and in sophisticated cases, even when the viewer is no longer in front of the television set. This data is somewhat more accurate than people maintaining a paper log, but unless the sample size is big enough, the final ratings are still mostly useless."
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cp9stc | Why LED TVs over 43 inches got poor viewing angles when same models of 43 inches and less got great angles? | Technology | explainlikeimfive | {
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"The term \"LED-TV\" is a bit misleading. They are LCD-TVs, but they use a LED backlight. And LCD in turn describes a bunch of different technologies that are similar, but work in slightly different ways. Now most TVs use what is called \"twisted nematic\", in short \"TN\". While good TN panels nowadays can have quite decent viewing angles, the cheapest of the bunch don't. So it might simply be that in this case, the 43\" TVs use worse panels than the smaller models. This can be because the large panel is too expensive, or the manufacturer simply doesn't make them in that size."
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cpa7an | How do graphics cards input graphics to screens? | Technology | explainlikeimfive | {
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"There's a great long video here of a graphics card built by scratch for an in depth example: URL_0 In short 3 pins on a VGA connector (the blue one with the 2 twisty bits on the end) are dedicated to red, green and blue. The voltage or strength of the signal indicates how much red, green or blue a pixel should have and those are condensed into a single pixel. This is repeated extemely fast for each pixel to create a full image.",
"If you've never done dioramas as a kid, this explanation might not make a whole lot of sense, but bear with me. Your graphics card is (simplistically) a large diorama box, and it's got all the elements of the game world loaded into its memory. The CPU is responsible for telling the GPU which elements go where, and how various elements are moving and interacting, but it's up to the GPU to actually render and draw them. This rendering and drawing process turns the three-dimensional diorama box into a two-dimensional picture, which is then sent frame by frame along the cable to be displayed on your screen."
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cpau9q | - How do spam emails get details about you? | How do spam emails know things about me? I keep getting spam emails threating to email people I know etc and on all of them it says “Your password is” and it’s not correct but at one point it was close and I’m just like while it wasn’t correct how do they know? | Technology | explainlikeimfive | {
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"Back in the days, many people used the same password for multiple sites. A few big sites got hacked, and lists of thousands of email addresses and passwords got out on the street. And you know that once something hits the internet, it's not going away, so there is a list somewhere with your email address and a (possible old) password next to it. Someone buys such a list and sends out a mass email with threats like \"I know your password and have seen you jack off to porn, cough up the dough\". Only a handful of gullible recipients are enough to make this scam profitable. You could check out [ URL_0 ](https:// URL_0 ) to see if your address occurs on such lists, as well as a list of major sites that have been hacked before. Just checked my own address, and it appears my address and passwords were part of hacks on Adobe, LinkedIn and Dropbox, so not small ones. PSA: always use different passwords for every site you register with, and use a well-known password manager."
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cpc9s2 | I've been watching those videos on YouTube where scammers get all their files deleted or a virus uploaded to their computer. How does the "Victim" do this? | Technology | explainlikeimfive | {
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"Usually the scammer wants to connect to your computer, remotely. Like when you are called by a fake 'windows support' person (they call you stating they are windows support and that you have a virus on your device they want to help you with), they want you to install VNC and open up a connection with them. Once connected, they rummage trough your files, copy whatever information they find or install spyware or other forms of malware. However you could have a virtual machine sitting somewhere with a windows installed and some malicious files packaged inside. Like a zip folder named 'E-Banking' that contains some crypto trojan or whatnot you want the attacker to copy and unpack on his device. When he calls, you connect that virtual machine to him and hope he falls for the little trap.",
"They convince the scammer to go to a web page that has the malicious code and trick them into downloading and running it. (Sometimes not even those last steps are necessary)."
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cpczj7 | How are companies able to copy manufacture Nintendo and Sega’s previous console without getting into trouble doing so? | Technology | explainlikeimfive | {
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"Any patents they had on those consoles have expired. Those old consoles are simple enough that it's possible to make your own compatible console without having to infringe any copyright. They didn't have an OS, so unlike a modern console you can make a clone of the console without having to rip the OS from the original. Games for those consoles are not encrypted, so there's no need to get around any laws against breaking encryption. So there's nothing to legally stop companies from making their own consoles which can play their games from the original carts.",
"Early consoles had no operating system - they were just a pile of hardware, most of which was off the shelf parts. The patents on hardware have expired so it's perfectly legal to clone the hardware now. The hardware was simple enough that it would be trivial to replicate it with a single FPGA chip (which probably costs $10 or less in bulk). Any software they had would still be under copyright but that's not an issue since there's no OS that is needed to make these older systems run. Anyone selling machines with a pile of ROMs installed is breaking the law.",
"You are asking the wrong question. I got a far more interesting one. Back in the Sega Genesis days, games made by Electronic Arts where shipped on cartridges that looked nothing at all like all the other cartridges for the Genesis. Why? Here is a good write up: URL_0 Short of it: EA games published PC games back then. Nintendo ruled the roost. Not only did Nintendo outsell PC by a huge margin - Nintendo had licensing that just sucked. EA didn't want to dive in with Nintendo. Sega was in the wings with a 16 bit system. EA went to Sega and said, 'Hey how about a partnership?' Sega replied, 'How about you license from us like Nintendo?'. They negotiated for a year, it ended in Sega telling EA to go fuck themselves and suggesting that if they wanted to publish they would have to reverse engineer.... Sega took them up on it. They 'clean room' reveresed engineered. You have 2 teams of engineers and a lawyer. Team one is 'dirty'. They take a Sega Genesis apart and do all the testing they want in any way they want. They then attempt to write up cryptic instructions for a 'clean' team that has no proprietary information. That information goes to a lawyer. The lawyer either passes it forward or sends it back. The 'Clean team' has no contact whatsoever with the dirty team. None. They have to put the Genesis back together using the instructions passed on from the Lawyer. It worked. Of course, EA couldn't ship the same cartridges as Sega. It held up in court too. Read the article. A fascinating piece of Video Game history."
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cpd4lv | What is the difference between code and script. | Technology | explainlikeimfive | {
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"Some people make a distinction between \"compiled\" languages that produce executable machine code & \"scripting\" languages that are either interpreted or compiled to a VM at runtime. Either way, it's still \"coding\" and the only difference is how the language is implemented. Compiled languages tend to be lower level & require more lines of code to get something done but you generally have faster execution times. Scripting languages are faster to develop in but run more slowly. There's not really any fundamental difference in the languages themselves & the distinction is generally made by people who are trying to inflate their ego & say the languages they work in are somehow superior to the \"scripting languages\"."
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cpfa7s | how does an airforce keep track of where its stealth planes are when they are on missions | Technology | explainlikeimfive | {
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"Encrypted communications. Plus, i wouldn't be surprised if they came up with a way to track their own stealth planes.",
"This is mostly secret but from history we know that a common tactic was to just plan out the mission before takeoff and then assume the pilots are able to keep to the mission schedule. If there are important deviations or checkpoints then these would be transmitted back in short coded messages. The mission details are also at a need to know basis with as few people as possible knowing about it at all. Even other airplanes working in the same sector might not know about the stealth planes and their missions which have caused some near misses.",
"If you’re flying a mission into hostile territory, you probably don’t have radar, so stealth plane or not, they are hard to track and it’s not happening. Instead planes use encrypted radio communications with each other and (hopefully) their base. However again it’s a good chance that these planes are flying far from their bases or they are worried about having radio give away their location, so they stop transmitting anyways. If you’re beaming out radio signals, you’re giving a clear sign of “hi, here I am!” That’s bad. Basically... you don’t keep track of them directly. The mission is planned, you track as long as you can, then hope all goes well until you can reestablish communication if it went out.",
"Depends on what it is, but one possibility (which is absolutely true for submarines), is they don't really. They leave, and wait a few hours for the reports. Military planes have plenty of transponders and such that go off in the event something happens, so they'll essentially drop stealth and broadcast away if needed. But in a stealth bombing run, it might be complete radio silence within 500mi of the target country, though they can listen covertly and will know if HQ needs to change their mission (which they can do without responding). And second, lots of people say encrypted comms, but that doesn't really help, the concern is people can pick up radio communications and locate the source. An enemy can see a stealth plane talking on a VHF radio, it doesn't matter if it's encrypted or not, encryption just prevents the enemy from understanding them, it doesn't prevent them from locating them. To that point, they do use directional antennas to stop that, basically they have special radios that transmit only up, and the military has satellites that route it back down. If the plane only transmits up, then only people above can locate them, this pretty much prevents ground and air forces from locating a stealth plane, but someone with good enough satellites could probably find the plane, so radio silence is still going to be the main thing."
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cpfapt | How do Pilots know where to land if they can't see the runway? | Assuming that they know that they're almost at the airport, how do they know where exactly the runway is if it's foggy? | Technology | explainlikeimfive | {
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"Planes have a lot of instrumentation that give the pilots information about the location of the plane. Runways are built with a specific heading or angle. As long as the pilot knows what his altitude is, the location of the plane, location of the runway, and the direction the runway is oriented, he/she can get pretty damn close to landing without actually seeing the runway. At which point they would be close enough to see the lights of the runway"
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cphlfm | What cause the modern unpopularity of ternary computing? What about it made it not able to be stable or work properly in many cases, and is the concept still under development? | Technology | explainlikeimfive | {
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"Binary is fundamentally easy on a hardware level: all your memory bits and circuits and transistors are either ON or OFF. Then you build out from there. Ternary requires more complex states, you need some way to measure magnitude or polarity instead of just crude on/off. It's possible and working models have been built, but the ease and low cost of mass-producing simple binary components basically priced it into oblivion by 1980. There's still *some* work going on since it would in theory speed up processes and shorten code, but the massive head start in minaturizing and mass producing binary components makes it a hard sell. Nobody's really shown that it can be cost competitive with binary systems of comparable computing power."
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cpiv8m | The NES and Gameboy Color are both considered 8-Bit. What are the technical differences in the graphics that allowed GBC games to look so different? | One thing I've noticed is that on Gameboy Color, there appears to be actually less allowable colors on screen, however Gameboy Color games seem to in general look impressive compared to most NES games. I have a bit of technical understanding but I bet there's a lot of folks out there who really know their stuff when it comes to the hardware specs and limitations. | Technology | explainlikeimfive | {
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"The 8,16,32,64 bits were just used to refer to the addressable memory range for the CPU. 8 bits means it could address up to 2^8 addresses, etc etc. We have been at 64 bits for the last 15 years or so and CPU/GPU performance has advanced a lot. Performance all depends on the specific hardware design. It was used as an advertising term back in the day to indicate how advanced a console was but it was practically speaking a rather meaningless metric. The differences in the graphics quality are due to the different hardware used in the two. One is a console that connects to AC and has the ability to use a lot of power and has space to cool. The other is a compact system run off batteries.",
"The main difference is related to the number of available palettes and palette slots. On the NES, games are limited to 4 background palettes and 4 sprite palettes at any one time, plus an overall background color. Each background palette consists of 3 colors, plus a special value for \"transparent\" (which is how the overall background color gets shown). Each sprite palette also consists of 3 colors, plus a special value for \"transparent\". This means that, without special tricks, the NES can only show 25 colors on the screen at one time. On the GameBoy Color, games have twice as many palettes to work with: 8 background palettes and 8 sprite palettes. In addition, the background palettes can each have their own color for the fourth slot, instead of it being \"transparent\". This means a GBC game can show 56 colors on the screen at one time. Aside from these differences, the NES and GBC have very similar graphics systems, with similar kinds of limitations. The fact that they are both \"8-bit\" doesn't really have anything to do with their graphics. It's more related to how the programming works, and the benefits of the \"bits\" aren't always noticeable to users. For example, the N64 was a 64-bit system, but the Wii and Wii U were 32-bit systems."
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cpldb9 | Zero Day Exploits and what makes them so rare? | Technology | explainlikeimfive | {
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"A zero day is just an exploit that isn't public or out there on the market yet. Basically its a known exploit, its not patched, and its gonna work as you expect. It's a \"new\" exploit. \"Zero\" as in zero days out in the public for it to be seen and fixed. These are rare because first of all, finding any exploit is difficult, a second because exploits often make their way out pretty quickly so they end up getting patched fast. A zero day just means an exploit that is currently unknown by the public or thing its exploiting, and its working. Having a zero day exploit is a massive prize to nefarious users, as they know its going to work. It may not work for long, but it will work now.",
"A \"Zero day\" exploit is an exploitable bug first discovered because it's being exploited already. It hasn't even been 1 day yet and already it's being abused. The name is kinda like the medical term \"patient zero\" - doctors learn of a disease because this person already has it. Exploiting a zero day requires finding it, keeping it quiet from others, and developing a useful (that is, useful for the bad guys) virus or other payload to make use of it. There's time and effort to be spent even for the bad guys and if the bug is leaked or just discovered by coincidence by another party it could be patched before the virus can be released. I'd like to point out that keep it quiet is REALLY important. Tech and IT is full of smart people and even a vague hint leaked about a bug can make people go looking in the right place to find it. It's happened many times before."
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cpm4wv | In old NES games, why would graphical glitches cause graphics to turn into numbers? | It doesn't happen often but I've seen it a few times. Why would NES graphics turn into numbers when they glitch out? | Technology | explainlikeimfive | {
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"It's because the glitch overwrites a memory pointer and graphics are stored at specific memory locations as a\"Sprite sheet\" which has all the graphics at specific location offsets. Think of a chess board with a graphic in each square. They are usually referenced using math offsets, and some squares are larger or smaller (text). When the pointer or variable is overwritten, like for example the start position of the image, or the Y axis, then you end up getting the wrong part of the image. There are literally thousands of ways a glitch can happen, or what it does, but in this instance it broke the image reference."
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cpp1jt | Actions you cannot undo in software | Technology | explainlikeimfive | {
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"Auctions are undoable if the programmer has programmed it to be undoable. If it is not programmed to be undoable, the default behaviour would be that the action cannot be undone. For your excel, even though you can't ctrl z it back, there's a longer way to get the sheet back. URL_0",
"Because the developers didn't deem it important enough to allow the users to reverse these actions. The code might have been designed in a way that makes reversing this action difficult, so the developers decided it wasn't an important enough feature to invest the time and resources in order to allow it. Meanwhile, Google Sheets developers might have designed the code so that it was easier to implement this feature, so they did.",
"In software, you can store stuff that the user doesn't see right now. For things that can be undone, either the whole previous thing was stored, or the changes made since a stored thing were stored. So you either go back to the previous stored things, or undo the changes in order. For things that cannot be undone, nothing of the previous thing was stored. Or it was stored then deleted.",
"Long story short, such actions don't exist if they're not programmed to handle those cases. It does take an extra amount of work and consideration for actions such as tracking what things a user has \"deleted\", hiding those things, and keeping them around in case a user actually wants to recover them. Normally, it's easier to just assume that when a user wants to delete something, we maybe give them a confirmation dialog, but then we don't think twice about it and truly remove data for what they wanted deleting with no way to get it back afterward. In general, there's been a shift of mentalities in how programs should work. Most used to be designed in a sense of \"the user read the manual, they should know what they're doing, we should give them all the power.\" to \"the user could be drunk for all we know, we shouldn't let them shoot themselves in the foot if possible.\""
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cpr8wo | Why do Characters like these exist in Unicode: Ñ̷̡͔̔̌̒͂̍́̈́͠ỏ̷̺͒̍̎̑̌͋̊́͗̚͠͝i̵̡̨̼͍͉͙̱͇̻̳̤̮̓̒͌͆̈̅̀̆̕ç̵̧̢̨̻̲̭̼̦̆̽̎͐́̍͂ë̶̪̖̬͇̥̭̹̟̯̝͛̊̓̑͊͘͝ͅ. What purpose do they serve. | Technology | explainlikeimfive | {
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"They're diacritics. Many languages have small bits and bobs that can be overlaid with other characters to modify them. On the simpler side, the double-dot (diaeresis) in \"naïve\" means that the I should be pronounced as separate from the preceding letter. Unicode, the purpose of which is to provide a way of representing all languages, handles those by having the marks as separate characters which are rendered on top of preceding ones. The Zalgo text in your example happens when someone decides to randomly pile every kind of diacritical mark available on top of the text which makes it seem like illegible gibberish. It doesn't mean anything when used like that.",
"They're combining marks. Unicode is designed to handle all human language plus a lot extra - which is a *lot* of potential symbols, so they built it to be modular. So a lot of characters are designed to combine. Like, you know how there are six skin tones available for emojis depicting people? Unicode doesn't actually have an character for black waving hand 👋🏿\", you use \"Waving hand 👋\" followed by \"Black skin tone 🏿\". Some languages need the ability combine characters together - like in Thai, vowels get stuck on top of consonants - and add pronunciation marks, and then what if you're writing lyrics and you need to add musical notation, etc. So they let you stack combining characters on each other however you want. What Zalgo text is doing is using a bunch of characters that attach to the top of the letter so they stack up, then going back down with characters that attach below the letter, then back up again so they overlap several times.",
"So that is 90 characters but most of them are combining characters such as accents and similar modifiers to allow UNICODE to support the wide variety of written language, people combine them in odd ways to make text look strange. You can see what some of them are here: [ URL_2 More on combining characters: [ URL_0 ]( URL_1 )",
"First, you have to understand that each of the shapes above and below the letter is its own character. So \"A\" + \" ̈ \" = \"Ä\", made of the two characters. The OP's Noice is at least 30 letters long. Second, there are lots of different symbols that you can add. Like any letter, each symbol has a particular use. For instance, you have probably seen naïve and jalapeño before. The pronunciation of the word depends on the use of the symbols. Unicode symbols are from english, spanish, french, and from every language that can be typed. This is particularly important when you consider Asian languages, in which the tone is as important as the sound. Here is an example: [Mother Scolds the Horse]( URL_0 ). In some languages, a letter might need 3 or 4 different symbols to tell the reader the correct pronunciation. Third, Unicode has a simple way of implementing these symbols. They move to a position relative to the preceding character. Like how \"A\" + \" ̈ \" = \"Ä\", you can continue adding and stacking symbols. \"A\" + \" ̈ \" + \" ̃ \" = \" Ä̃ \" So when looking at the Noice in OP, the oddness of it comes from the fact that it is at least 30 different letters, some of which are just overlapping. Unicode isn't intended to be used to that extreme, it is just a bug in how the symbols are expressed. & #x200B; ======= I will be editing this to make sure it formats correctly. I don't understand how to get Reddit to display Unicode character.",
"That specific example is Zalgo text. Zalgo is an internet creepypasta based on an incorporeal, malevolent entity that drives people insane."
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cpv44o | How do some radios know the name and artist of the song that's playing? | Technology | explainlikeimfive | {
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"Along with the signal that carries the music, some radio stations broadcast a signal through the RDS protocol (the Radio Data System.) Usually the signal is the station ID, plus the artist and the song. If your radio can interpret the RDS protocol, it will display that information. It's more common in newer radios, especially in cars."
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cpvpou | How do 'I am not a robot' tick boxes work? | Technology | explainlikeimfive | {
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"Do you mean in cases where you just tick the box, and the page accepts that you are human? Usually pages that use that feature are monitoring your activity across the entire page. Every move of your mouse, click, box filled in, etc. The algorithm is pretty good at telling just from that if you are human or a script. If it thinks you’re a bot, it will ask you to do something more difficult to double check - like pick out all the pictures of stairs.",
"By robots, you mean computers. Computers are very good at solving exact problems, like advanced calculators, but not so good at anything that requires the slightest bit of creativity. When learning some programming, my prof always reiterated: computers are dumb. It's your job to make them do smart stuff. So when you are asked out of the blue to figure out a squiggly letter or point out a street light, computers are really bad at that kind of task. It would take a really well programmed computer some time to do that, but it takes a human no time at all. No one is holding their hand and telling them what font the script is or how big the light is going to be",
"Many factors are considered......did you click the check box almost immediately after it loaded? How much time did you spend on the page before clicking? What's your browser's UserAgent string (used to identify what browser you used)? What site did you browse from to get here (referrer)? etc. It attempts to make a determination based on the above and more. If it determines it doesn't think you're a bot, it lets you through, if it isn't very sure whether you're a bot or not, it prompts you with more questions (such as pick out the traffic lights in this image or something). EDIT: Can the above be faked? For the most part, yes....but the difficulty in faking it well enough to bypass all of the checks successfully usually isn't worth the effort. And analysis of what your bot does would allow the developers of the anti-bot system to add additional measures that you bot doesn't defeat, forcing you to rewrite your bot."
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cq47f8 | Why do most instructions say to leave a device unplugged for “x” minutes to reboot? | Technology | explainlikeimfive | {
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"Most power supplies have capacitors. Capacitors build up charge and then dissipate it. Think like tiny batteries that lose charge in seconds. So you leave devices unplugged so that the capacitor is fully discharged and therefore not feeding even a minute amount of power back into the device. Completely rebooting the device.",
"It's usually only a few seconds and it's because capacitors which are kinda like little batteries will hold a charge for a little bit",
"If a device has a capacitor it'll store enough power to last a few minutes. The wait until is too make sure the device actually shuts off after that power runs out."
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cq5m7s | Why is there so much unpredictability around bank transfers? Why can't they all be instant? | Technology | explainlikeimfive | {
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"In the U.S., we still use the [ACH System]( URL_1 ), developed in the 1960s. Basically all the transfers that start at a bank in one day are made into a batch at the end of the day and sent to a central processor, who then routes them to the banks at the other end of the transfer for approval. The paying bank picks up their messages the next day, has an extra business day to decide whether or not to approve, and sends their batch of rejections (but not approvals!) to the central processor the next night. The receiving bank then picks up their batch of answers the next day. Since they don't get approvals, only rejections, and the other bank has another day to reject, they usually wait that extra day. They also skip weekends and holidays in case anything needs human review, and of course there's a cutoff time to get something in in time for tonight's batch, so if you're late it goes the next business day. So it can be 3 days to a week or so, depending on timing, weekends, and holidays. [How ACH Works]( URL_0 ) is a more technical explanation that's not ELI5, but might explain the timing better. As to why we still do this, it's just because they spent vast amounts of money making the systems and processes, making them all capable of following the same standards, making them all robust, and building their processes around that. They're known to work (most of the time). Building new systems would be expensive, risky, and they'd have to redo all their processes, and importantly until all the other banks are doing the same thing in the same way and they can all talk to each other, useless. Yes, of course everything could be (almost) instant. But there's not a big enough push for it to overcome the inertia of the existing system.",
"I'll try an actual ELI5 instead of a history of mainframe computing :) When you send money to someone, your bank gives money to the other person's bank. In the old days, banks would call each other and agree how much money they owe. They only called once a day, because if they called every time someone sent money, that would be a LOT of calls. Later we got computers, and when we sent money, people put the numbers into computers. Because banks were used to calling each other once a day, they built the computers to work the same way. They also did it because they didn't quite trust the computers, so they wanted to check that the computers got the numbers right. Today computers are so good that we always trust their numbers. Because computers are very fast, that means all money could be sent in a second. However, many banks still have their old computers, who only know how to call each other once a day. Most banks are buying better computers, but it will take years before they all have them, and until then, sometimes it will take a day or two to send money.",
"Everything can be instant. The US is a long way behind the rest of the world in a great deal of services 'stuff', things which don't get noticed as much because they just 'are'. A bank transfer takes place immediately in the UK (usually or at least within 2 hours). Think how long it took the US to get chip and pin or even contactless. It still isnt ubiquitous tech that has been standard for much of the world for 10 years. The simple answer in an ELI5: Why can't it be instant? Because US banks don't want it to be or wont change their processes because of potential cost.",
"Others have answered better, but it is worth pointing out that it does vary depending on URL_0 Australia, for example, [there is a method]( URL_1 ) for near instant bank transfers.",
"In Canada, transfers under a certain limit are instant, I can email/text money to other people and that’s pretty much instant.",
"In much of the world it very much is. In Norway we have apps on our phone where I can pay my bills instantly, I can send money to anyone who has the app and they'll instantly get the money and all I need is their phone number. If I use regular online banking it's occassionally a bit slower if the transaction is between different banks, as they process payments a few times a day, so if you send money at night it won't arrive until the next morning. The US is slower because they use outdated tech (ACH) and are terminally afraid of change and potential costs incurred.",
"Money transfers between banks are instant in India. PS. Is this some kind of US joke I'm too Indian to understand.",
"It's only a thing in the US .The rest of the world has instant bank transfers.Even the American ones that operate in our country have that.",
"> Unified Payments Interface (UPI) is an instant real-time payment system developed by National Payments Corporation of India facilitating inter-bank transactions. The interface is regulated by the Reserve Bank of India and works by instantly transferring funds between two bank accounts on a mobile platform. As of March 2019 there are 142 banks live on UPI with a monthly volume of 799.54 million transactions and a value of ₹1.334 trillion(US$19 billion) URL_0",
"Because while the money is in transfer it's not in the sender's account and not in the recipient's account, meaning it's in the bank's account and the bank earns interest on it. Banks have zero incentive to speed up transfers.",
"Money laundering is also one thing to note. They have to run the transactions against block lists of known criminals, suspicious organizations and countries etc.",
"In the UK payments up to a theoretical limit of £250,000 are instant. Throughout the EU payments are completed usually within an hour or two, and soon will be closer to instant. Edit: In fact cheque deposits are instant at cash machines (ATMs) and in-bank in the UK.",
"If you’ve got 20 or so minutes you can learn all about it from [this episode of planet money]( URL_0 )",
"I currently work for a bank, so can answer this shortly: the main reason is legacy software and hardware.All bigger players still work (for the biggest part) on mainframe where it used to be handled using daily/nightly batch processes because of performance. But nowadays people (and regulations in Europe) want instant transfers, meaning they need to re-engineer their processes on mainframe. Back in the day mainframes weren't so performant so that's why they needed batch processes, but mainframes nowadays are such powerhouses that the argument is completely moot. It's important to note that every bank works in their specific way, so it's possible some things aren't setup in an optimal way and can buffer transactions for a bit. PSD2 will change this to some extent. TL;DR: they can be instant if they want, but some postpone because of legacy reasons.",
"They kind of are, depending on what you're talking about. As far as deposits via check it has to be approved and such. In terms of ACH it is instant just the 2 communicating banks are slow with the approval process. To help with fraud and all that.",
"In Greece transfer between same banks, instant. Different banks, 1 or 2 days. To other countries, 1 week or more",
"ACH in the US is similar to BACS in the UK, both pretty old technologies, batch run end of day usually, although you can kick off a single BACS run if you need to (and it happens all the time) . SWIFT is the international version which uses IBAN numbers. It's changed recently in the UK with the introduction of 'Faster Payments'.",
"Everyone in the comments seems to put the blame on old banking systems and say that it could all be done much faster by upgrading the system. In reality the systems are up to date and the bank doesn't wait the end of the day because that's what they used to do in the old days. Each party involved n the process waits for a day and then moves on to the next step to make sure that the transaction is regular and not fraudulent. This time lag allows for all the parties involved to triple check the validity of the transfer and make sure that who sends the money is both willing and able to send the money and who is receiving the money is also willing and able to do so. All this time lag is necessary to ensure that if someone is being scammed they have the time to realise it and stop the transfer before it's too late. Some banks nowadays allow one-day transfers between accounts of the same bank as they trust their systems.",
"Because the banking system, especially in the United States, is held together by fax machines and scotch tape. Everything the customer sees is pretty modern and fast, but where the rubber meets the road and things like credit card systems interface with accounts to actually move money around, it's insanely old & rickety. The actual systems that hold accounts and balances are mainframes that are 30+ years old, running code that hasn't been updated in decades, and those systems are slow and only do batch processing at the end of the night. It's terrifying. The fact that they work at all is unbelievable. If you actually knew how banks operate day to day, you'd never give them a cent.",
"Isn’t it becasue the banks want to keep our money for a day or two? Then they use that money to earn interest overnight in other markets?",
"Former foreign exchange (FX) Product manager here - I quit due to not wanting to sell my soul any longer. So all retail FX trades are specifically designed to screw over the customer. A retail customer is the little guy like grandma going to Europe for the first time. Big corporations can negotiate a lot like when the trade is “priced” or the basis points applied (see below) but even then if they can get shafted - I know. I was VERY good at my job. Buying euro with USD? The trade will happen at some point in the day that’s most beneficial to the banks. They aggregate the anticipated buys for the day and then time the buy for what they think will be the best rate of the day. The retail customer is then applied WORST rate of the day to the trade even if the bank actually bought at a really beneficial rate. The bank makes the difference. Feeling screwed.....the basis points haven’t been applied yet. Those are the fees. Total gravy to the banks. So profit all around and the little guy gets shafted. TravelEx can suck it.",
"Google the company Ripple. They have been building a blockchain based solution for years and years, they have many banks/cross border payment companies on board. Transfers take 4 seconds for confirmation and settlement.",
"America is pretty much the only advanced nation that still uses dated banking and transfer systems. It’s why y’all have Venmo when in most other countries like Canada for example, we can just do instant transfers directly through our banking apps.",
"Transfers/Transactions are 2 parts. Payment and settlement. Payment is instant and very easy. Settlement is harder and involves a lot of movement and coordination behind the scenes with the current/classic banking system. ACH/SWIFT is very slow. Future will look like Ripple/XRP. Instant Settlement based on federated byzantine consensus",
"One reason is the banking industry (and countries) making money off the \"float\" -- money that exists in multiple places at once during these transition periods. Bank transfer agents make interest off it and countries manipulate the value of their currency by allowing more or less float to exist at any given time. Could it all be instant? Sure... but that would remove a source of income and currency value lever.",
"I'm presuming that you are referring to the banking system of a specific country, or wire transfers in general? Different countries may have different standards, and perhaps in some places the delay may be indistinguishable from \"instant\". That said, when it comes to handling money, there has to have some reasonable delay to account for due diligence. (Is this your money being moved around? Is the beneficiary who they say they are? Was the instructions to move the money around forged in any way? Things of that nature.) Also, keep in mind that the concept of electronic funds transfer and automated clearing houses is not some cutting-edge technology that should be adopted; automation in the banking industry has been around for a long time; for example, the ACH Network in the US has been around since the 1960s-70s, and has constantly been refined, but is still well short of \"instant\" due to the way the banking system works there.",
"This is actually a hugely complicated subject that a person could take hours to explain and discuss but here's the simplest way I can figure to put it: S.W.I.F.T. (Society for Worldwide Inter-bank transactions.) Is the entity largely responsible for transferring money from one bank to the other. SWIFT has been around for a very long time (not sure how long exactly but I'm pretty sure it's like 100+ years.) As such it has a relative monopoly on bank transfers. Right now, the actual system swift uses to transfer money is based on a Telecom network. Telecom technology has gotten better over time but it's not a particularly new technology, so as a result, Bank transfers today take about the same amount of time as they did when the system was first invented. The reason they're still so slow is because SWIFT and the institutions that use it have no incentive to make it faster. The main thing that creates incentive for aging markets to progress is competition, and SWIFT has none. Blockchain technology is an example of a disruptive technology that can make financial transactions lightning fast and secure--and it is poised to disrupt the financial transactions market. However, this technology is still very new, and banks in general are very large institutions with low risk tolerances and are resistant to change--as a result, they will usually be the last to actually adopt infrastructural technology improvements. (They might invest in new tech early on, but they won't adopt it for their own operations until they're absolutely certain it will pay off at the scale they need it to.) TL;DR - Financial Transactions are based on an old system that's entrenched and very difficult to displace, despite the fact that better technology already exists"
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cq7xvx | rimfire vs centerfire cartridges | Technology | explainlikeimfive | {
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"In order to get the primer explosives to detonate you need to compress it. Normally you would have a hammer and an anvil to make the necesary pressure to detonate the primer. This have to be done through a thin section of the cartridge wall in order to keep the pressures generated by the primer inside the cartridge. Rimfire is a very inexpensive way to do this. The anvil is the front side of the cartridge rim. So the hammer will compress the rim of the cartridge and compress the primer in the rim. This does not require any complex manufacturing to make the cartridges. The disadvantage is that the cartridge can not have thicker walls then the hammer can strike through which limits the pressures the main charge can generate before it ruptures the cartridge and releases gasses into the action of the gun and into the shooters hands and face. This also leaves the gun unusable until the debris can be cleared. Centerfire cartridges are more complex. There is a seperate primer with its own cartridge walls and a seperate tiny anvil to strike against. This is then glued into the bottom of the cartridge with only a tiny fuse hole to allow the hot gasses from the primer to get into the main charge to detonate it. This design does allow for a much thicker cartridge case walls as the hammer only needs to collapse the thin primer walls and not the main cartridge case. However due to the more complex manufacturing involved centerfire cartridges is usually more expensive. Some costs can be recovered as the cartridges can often be reloaded by replacing the primer."
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cqbunp | Why are passwords that mix uppercase/lowercase and alphabet/symbols considered more secure? Don't hackers have to try every combo anyway? | I see tips like this all the time. Assume a properly randomized password, let's say "bvi1oyn7mo." Is that really less secure than "bvi1OyN7Mo?" | Technology | explainlikeimfive | {
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"Password crackers may start by using a program that only tries combinations of lowercase letters (and/or numbers), as it will take much less time to try every possible password. Your first password would eventually be found by this faster program, and the second one would require a program that includes capital letters and takes a lot longer to run. Be aware though, the absolute length of the password is much more important to make it difficult to crack than other factors, as [this xkcd]( URL_0 ) explains. Personally I combine the two methods, using passwords like Correct-Horse$Battery=stapLe",
"Yes and no. A random password is a random password whether it’s all lowercase or not. If I’m a hacker and I’m trying to brute force your password by guessing random passwords, I’m just as likely to guess all lowercases as a mix of cases so it doesn’t really matter. You also usually can’t brute force a password anyway, most websites lock you out after a certain number of incorrect guesses, but, even if they didn’t, it would literally take super computers at least decades to brute force most modern passwords. We think computers are real fast, but any conventional computer that operates within the laws of physics will almost never be able to try every combination of passwords fast enough to get the right one in any useful amount of time. People are saying it is actually more secure because it gives a hacker more characters they have to guess out of when you use capitals, but if capital letters are an option, it doesn’t matter if you don’t use them. The hacker won’t know that. That’s like saying if your password doesn’t have the letter ‘G’ then it’s less secure because the hacker can just use an algorithm that doesn’t use the letter G and still guess it even faster. Sure, but they’d have to know you didn’t use a G in your password. If you *can* use capitals, a random password is realistically no more or less secure if it just by chance didn’t use any. However, most passwords are not random, and websites (and hackers) know this. Most people don’t use a password manager or something and so they use passwords based on things they can remember, like a sports team they like or something. So let’s say you like the Yankees, your password might be “Yankees19”. If I know you, or even just overheard a conversation about how much you like baseball, then that’s not too hard to guess, it’s your favorite sports team and the current year. But if you make your password “YaNkeEs19!” Well now it’s a lot harder to guess. It’s not enough to just know your favorite sports team because you’ve psuedorandomly capitalized some letters. You’ve already increased the complexity by a fair amount for someone who has to guess it, but you can still just remember it’s the Yankees with some capital letters. I also think realistically a lot of websites say that just to get you to stop and think instead of putting something trivial for your password just to finish your account creation. Just saying to use a secure password probably doesn’t stop as many people as not letting them move on unless they have a capital letter and a special character, at which point they’re more likely to just in general try and think of an actually good password. The moral being, it doesn’t matter for random passwords, but for the typical not random passwords most people use, it makes it harder to guess strategically.",
"Trying every combo is what's called brute forcing. And yes, brute forcing will eventually reveal *any* password you could possibly use. However, trying every combination of every character takes time. Using your example of \"bvi1oyn7mo.\", the number of combinations possible if you know there are only lower-case letters and numbers included is 68^11 or ~143.75x10^17 possible combinations. This is a result of 26 potential letters (lower-case) plus 10 potential digits plus 32 potential special characters (the period but also any other special characters) over 11 total characters. If we use your second example (\"bvi1OyN7Mo?\"), adding upper-case characters, you now have 52 letters (upper+lower-case) plus 10 digits plus 32 special characters, you now have 94^11 or ~506.29x10^19 possible combinations. In terms of password cracking, lets say you can guess 5 billion passwords per second in perfect conditions. The first password would take a maximum of about 911 years to try every combination, the second password would take about 32,109 years to try every combination. **ELI5:** In this example, by increasing the potential types of characters in a password by only 34%, you increase the time it would take to brute force that password (everything else equal) by up to about 3,524%. An interesting note though, by increasing the length of the password in your first example by one 1 character, you increase the possible combinations to ~977.47x10^19, which is increases time to brute force that password to 61,991 years. This is an increase in length of only 9%, but an increase in maximum time to brute force of about 6,804% In short, password length and complexity (number of different types of characters that can be used) both increase the time it takes to brute force a password, length is more important beyond alphanumeric characters (upper/lower-case + numbers) assuming you enforce policies that prevent other types of password-cracking attacks."
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cqddx1 | Is it possible for the internet to "Go Down" | Technology | explainlikeimfive | {
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"Not really. Firstly, it would have to be on the infrastructure side, but even if the biggest telecom cables and infrastructure were taken out, you wouldn't lose the entire internet. You could still access whatever you can access locally. It would be like asking \"is it possible for driving to be impossible\" if freeways were removed.",
"Not the whole thing. I mean unless a solar flare disrupts electronic devices on a global scale. It's definitely possible for the internet to \"go down\" in local areas though. I'm pretty sure you're asking if the internet can go down because of a small number of servers going down and the answer is no, not in its entirety. If all the Google servers go down we could be deprived of Google and websites hosted by Google, but everything else would be up. Many people host their own small websites with small servers in their houses or offices so even if every major server building was shut down there would still be stuff on the internet. Also by definition the internet is just computers that are connected togother with the ability to send and receive information so the concept of the internet still exists as long as at least 2 computers are connected in network. In a more realistic example the global internet could \"go down\" with the destruction of a couple satellites and the cutting of a few transatlantic cables. We would cease to be connected to the Western hemisphere. I wouldn't worry about it though."
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cqdetw | How does flashbangs work? | Technology | explainlikeimfive | {
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"A flashbang contains a mixture of magnesium or aluminum, ammonium nitrate, and a powerful oxidizer like potassium perchlorate. This produces a very bright flash and a very loud bang when the fuze sets it off., hence the term flashbang."
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cqec15 | How does upscaling game textures like this work? how can it create data that wasn't there? How can I do it? | URL_0 | Technology | explainlikeimfive | {
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"First, get hold of a huge amount of high resolution textures of all sorts of things you see in games, bricks, wood, faces, guns e.t.c. You could take these from modern games. Now down sample these high resolution textures to low resolution textures. Now train a machine learning algorithm to go from the low resolution textures back to the high resolution textures. The algorithm will learn how the features of the low resolution textures link to high resolution ones and can therefore generate a new texture. Essentially the algorithm is learning \"things like this should generally be like this\", and with enough data that should cover most textures seen in games. (These things can make mistakes though!) For example the algorithm might recognise a surface as a brick wall, and from all the knowledge it has of what a high resolution brick wall looks like, it will generate a new brick wall texture. It's not actually up sampling, it's creating a whole new texture that matches the features of the low resolution texture (e.g brick spacing, overall color e.t.c)"
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cqf3ls | Questions about technological advances/the singularity | You know how you go and buy a new graphics card/processor and it says it's the latest and greatest, and then another one comes out shortly after? My question is, what exactly is driving these technological "advances"--i.e. what discoveries or scientific breakthroughs are being made every year that makes the next piece of tech better than the last one? What are we lacking at the moment that developers/engineers are trying to improve on for the next iteration of hardware? At what point does "the singularity" happen and there are no further advances to be made? Will that ever happen? | Technology | explainlikeimfive | {
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"I can answer part of your question. In recent years processing power for GPUs and CPUs is based on transistor number and transistor size. In essence, how many transistors can you cram together in a single chip or card. The more transistors the more and faster calculations can be made. In your graphics cards example, Nvidia for example presented their Turing architecture in 2018, that replaced previous architectures like Pascal. Turing has transistors that measure 12nm, while Pascal had 14nm or 16nm transistors. So turing architecture cards are faster or more capable in some ways because they have more transistors in the same space. This is a gross simplification but passing from 14 to 12nm is a big deal, as it implies a lot of progress was made in a lot of fields (nanotechnology, chemistey, engineering etc) Basically nvidia couldn't have invented all the sudden the best possible graphics card. It is a complex process that implies a lot of work from different sectors and discoveries or advancements that build upon each other. The \"best cpu you can buy\" bascially means there is no technology cheap enough that exists today that would make selling a better processor worthwhile for mass consumption. Something similar happens for quantum computers. They are extremely useful for some fields but they are extremely expensive to make so they will not break out of the research stage untill they can be scaled down enough to be sold at a price that benefits the manufacturer. So, TLDR: there could be better gpus/cpus today, but it would be too expensive/too complicated to mass produce. A lot of different fields need to work together to allow for you, a random customer, to get high end gear"
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cqgpuo | Why is it that if you take a picture of a computer screen you often get those wavy lines but if you zoom in on the picture a little they go away? | Technology | explainlikeimfive | {
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"Those patterns are known as [Moiré patterns]( URL_0 ). These patterns occur because your computer display is a grid of evenly spaced pixels being captured by a grid of evenly spaced of pixels on your camera sensor. If the grids completely matched, you wouldn't see any difference. However, this is unlikely so any shifts due to pixel differences or positioning causes the grids to be offset. This produces the wavy or interference patterns that you see. Scaling an image on a display changes how many pixels make up the image (an image is also a grid of pixels). This can sometimes make the pattern worse or better."
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cqh4ug | Can Phones Charge Past 100%? | Does keeping a phone on the charger after it's already hit 100% really have no effect whatsoever? | Technology | explainlikeimfive | {
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"No. You can't do anything past 100% When the phone reaches 100, it simply stops charging, whether it's plugged in or not.",
"One of my phones charges approximately another 8% after the display reads \"100%\". You can then unplug it and it will continue to read \"100%\" for hours. This is because android and the battery controller are not agreeing about what \"100%\" really is. When your phone is plugged in, it will not be drawing current from the battery, or will be drawing much less. This greatly improves battery life, and decreases resource usage required to replace it. Modern chargers draw very little extra power. Ignore Google, Android is wrong when it nags you to unplug your phone. This would actually cause increased energy using, assuming you will replace your battery after you wear it out due to applying unnecessary charge cycles to it.",
"Phones and laptops have charge controllers. They decide exactly how much and how fast they want to charge. For instance I can tell my laptop to stay at 90% and not go any higher. This increases the battery's longevity. So yeah, when it decides it's done, it doesn't charge anymore and just runs from the power cable."
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cqhpld | If I have 10mbs upload and 150mbs download speed, why does streaming and downloading become nearly impossible if I am trying to upload a large file? | Technology | explainlikeimfive | {
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"ewwcl6o",
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"text": [
"because the TCP protocol utilizes handshakes along the way. so you also need to upload (acknowledge data received every now and then), so if your upload is already fully utilized, you can't acknowledge those packets sent, and so the sender doesn't send anymore.",
"Uploading is like speaking and downloading is like listening. While uploading a big video, it’s like you’re trying to read the Illiad at Rap God speed. Imagine trying to ask for the next bit of your video stream while doing that. Your computer can only ask other computers for data so often and uploading a video takes up all of your “speaking” ability."
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cqhyei | Why is it possible to break two layers of encryption? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"> this is assuming the attacker dosn't know how many layers of encryption there are Maybe the attacker doesn't know how many layers of encryption there are. But they don't have to know. Suppose the attacker is able to brute force single-layer encryption in 1 week. If you use the same key for both encryption layers, they just have to randomly guess \"hmm, one layer didn't work, so let's try two layers,\" and then you are doomed, since brute-forcing two-layer encryption with the same key on each layer will only take 2 weeks, which is still short enough to be feasible. You can work around this problem by using different, independent keys for the two encryption phases. Now they have to guess both keys right to decrypt your message (in addition to guessing that you used two layers). If they guess one right but the other one wrong, they get a random-looking result and have made no progress. Unfortunately, this runs into an additional problem called the \"meet in the middle\" attack. This is a known-plaintext attack, so one assumes that the attacker knows both the plaintext P and the ciphertext C of one of the messages. The attacker now does two things: 1. encrypt P with each possible key, and make a list of the results. (All of these look like random noise.) 2. decrypt C with each possible key, and see if the result is in the list made in step 1. Eventually you will find a key in step 2 so that C decrypts to something in the list. At this point you have actually found both keys from the original algorithm. This procedure takes a lot of storage (because you have to make a big list in step 1) but is much faster than trying to crack both keys at once by brute force. Because of this problem, using two layers of encryption doesn't provide as much additional security as you'd hope, and so this is not used in practice. Three layers, on the other hand, does provide more security than one layer, though now you have to have three independent keys. The \"Triple DES\" encryption algorithm is a famous example."
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cqid5z | How do sleep trackers work? | How do sleep trackers work? Do basic, consumer grade, wristlet style trackers work similarly to medical grade? | Technology | explainlikeimfive | {
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"text": [
"They don't know, not exactly. Not a doctor, so I don't know biochemistry that goes on when we sleep. But apple watches for instance sure doesn't measure chemicals in our brains when we sleep or whatever. These sensors uses algorithms that predict when someone is sleeping. The other comment makes it seem bogus but they analyze millions of data points of heartbeat, movement and maybe sound. They develop trends and make assumptions. Like with x amount of movement at night paired with lower heartrate and the fact that the phone has been off for 2+ hours, my owner is sleeping. (very crude example). When they have an acceptable error rate, they push it onto their products. They also rely on feedback from consumers in alpha, beta phases of the product. That's the beauty of tech and engineering. Most products are dumb. Sensors and a cpu. How we make them work makes it smart."
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cqjdpn | I’m watching a TV show and romans are wearing white robes. How did the Greeks and Romans keep clothes white? | Technology | explainlikeimfive | {
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"text": [
"Aged urine and sulfur fumes were the laundry and bleaching methods of the Romans according to the wiki. \"Basic laundering and fulling techniques were simple, and labour-intensive. Garments were placed in large tubs containing aged urine, then well trodden by bare-footed workers. They were well-rinsed, manually or mechanically wrung, and spread over wicker frames to dry. Whites could be further brightened by bleaching with sulphur fumes. Some colours could be restored to brightness by \"polishing\" or \"refinishing\" with Cimolian earth. Others were less colour-fast, and would have required separate laundering. In the best-equipped establishments, garments were further smoothed under pressure, using screw-presses. Laundering and fulling were punishingly harsh to fabrics, but purity and cleanliness of clothing was in itself a mark of status.\"",
"The ammonia in urine was also used to clean togas in a place called a fullery. The first stage of cleaning involved men jumping up and down on the togas in large vats with urine inside, like living washing machine agitators, while the second stage often included dirt or ash. Both helped dissolve grease that accumulated on the togas and made them bright again."
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cqpbt0 | How do traffic lights detect that a car is waiting at a red light? | Technology | explainlikeimfive | {
"a_id": [
"ewy4clh",
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"text": [
"I work on traffic lights. There is a small cable coiled up in the ground that when a car passes over it or sits on top of it, it sends a magnetic pulse in to the cabinet where it will decide when it will change green.",
"In addition to the magnetic coil discussed already, many large cities are moving to a camera based system in which a video camera can actually count the cars that are waiting and determine when to change the lights and for how long. From a traffic management perspective this is much more efficient than the simple car or no car information provided by a magnetic coil. The cameras can also detect accidents and wrong way drivers (they are currently being used for this in Phoenix and have had good success)."
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cqqkas | Why is black ink in markers and ballpoint pens made up of colored ink? | Technology | explainlikeimfive | {
"a_id": [
"ewyfqbi"
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"text": [
"If you were to mix all three of the primary colours together, you get black. Depending on the amount of each of the three colours you can get a black that may have a slightly 'off' kind of hue, which may to lean towards being a dark green or red/brown."
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6
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cqu2hj | How does Nagel's Algorithm work, and why does it help lowering the latency while playing real time online video games like League of Legends, DOTA and Rainbow Six Siege? | Edit: I meant "Nagle's Algorithm" in the title. Whoopsie | Technology | explainlikeimfive | {
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"text": [
"Nagle's Algorithm works by sending fewer but larger packets instead of flooding the system with small packets over a TCP connection. It's like filling a city with cars vs buses. When everyone has a car people can leave point A whenever they are ready but they move around the city at a slower pace because there's a *lot* of cars on the road. If you instead outlaw cars and only allow buses, people may have to wait around a little bit to leave from point A, but there's fewer vehicles on the road so those vehicles can move around a lot more smoothly. However, most real-time online games, LoL included (I didn't look into the others you named), use UDP which has significantly lower overhead and is preferred when packets are time-sensitive. As such, most real-time online games *do not* use TCP or Nagle's Algorithm."
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cqu3sr | Why do people use rocket fuel instead of nuclear power for spacecraft? | Technology | explainlikeimfive | {
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"text": [
"There is always a non-zero chance that a rocket will explode when launched. The early ~~Saturn V~~ pre-Mercury rockets, the Space Shuttle, and new SpaceX rockets all have had numerous explosions during launch or re-entry. If a nuclear powered rocket were to explode, it would spread nuclear material over a very large area - an incredibly large area if that explosion happens high in the atmosphere. This would be a catastrophic event, and even at low probability of occurrence it is a significant enough danger to make nuclear propulsion a bad idea.",
"Nuclear reactors make heat. Heat isn't particularly useful in and of itself. Heat can be turned into electricity through a number of types of cycles, that's how spacecraft use it, as well as the nuclear plant down the street. Electricity isn't that useful in propulsion, as electrons have very small mass. To move a rocket, you shoot **stuff** out the nozzle at high speed. There is a relationship between the mass of the stuff and the speed of the stuff that determines the thrust of the rocket. To make a nuclear powered rocket, you need the nuclear reactor **plus** stuff to shoot out. With a chemical rocket, the combusted fuel used to make the energy **is the stuff** shot out. there is no energy transfer (or 100% efficient energy transfer if you prefer) which gives very high efficiency. The nuclear solution has to transfer the energy to the stuff, which is less efficient. TL;DR: High weight (for safety) and low efficiency makes nuclear energy a bad rocket choice.",
"Nuclear power generates heat which is not possible to cool in the vacuum of space since there are no air molecules for conduction and convection of heat to take place."
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cqu5w0 | why do images load by first showing the entire picture distorted, then clarifying. Back in the day, they loaded slowly from the top down. | Technology | explainlikeimfive | {
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"text": [
"This is a product of what is called **interlacing**. Basically, an image will store every 8th pixel first - so if you just get the first chunk of data, it'll be the 1st pixel, the 9th pixel, the 17th pixel etc. This amounts to being a low-resolution version of the image, so it's very fast to load an image that just shows every 8th pixel. Then you load the next line and it's every 4th pixel, then every other pixel, then finally every single pixel. (This is the simplified ELI5 version). Old BMP or GIF images didn't use interlacing (though interlaced GIFs are commonplace today), so when you loaded them, it just loaded the first line of the image, then the second line, then the third... which came out to the top-down loading you saw. Interlacing only \"works\" if your browser supports it, and while interlacing is old, older browsers often did not support it and an area would just be blank. Sometimes a website will cache a lower-res version of an image and serve that to you first if it detects that your connection is slow.",
"It's progressive jpeg. Basically instead of the image data being stored line by line, it's stored as a series of passes over the whole image, first at low quality, then each pass increasing the image quality. It gives you the whole image quickly because the lowest quality first pass is a tiny amount of data, and increases quality of the image over the rest of the download, instead of increasing the quantity of the image. [ URL_0 ]( URL_0 )"
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cqudpj | If websites store passwords as an unreversable hash, wouldn't that mean multiple passwords can unlock your account? | If I understand correctly, lots of websites convert your password to a hash and then check login attempts against that hash. Hashes are held in high regard because they are unreversable, but it seems to me that the only way this is true is if there are multiple values that the input could be, which would mean multiple passwords would calculate the same hash. | Technology | explainlikeimfive | {
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"> but it seems to me that the only way this is true is if there are multiple values that the input could be, which would mean multiple passwords would calculate the same hash. Why? It's theoretically possible and referred to as a hash collision, but for any modern encryption the risks are basically zero for purposes of \"someone enters the wrong password and gets in\". If your password is cakeisgreat123, and your password hash is ca9f22184dbb7b1898058acf52cf3b2b00e1331acedb8c30a9e641f7a011a969, the chances of say, dkf295isgreat also resulting in ca9f22184dbb7b1898058acf52cf3b2b00e1331acedb8c30a9e641f7a011a969 is essentially zero. If you want an example of what \"essentially zero\" is, [here's an amusing example]( URL_0 ): > what is the probability that a rogue asteroid crashes on Earth within the next second, obliterating civilization-as-we-know-it, and killing off a few billion people? It can be argued that any unlucky event with a probability lower than that is not actually very important. > If we have a \"perfect\" hash function with output size n, and we have p messages to hash (individual message length is not important), then probability of collision is about p2/2n+1 (this is an approximation which is valid for \"small\" p, i.e. substantially smaller than 2n/2). For instance, with SHA-256 (n=256) and one billion messages (p=109) then the probability is about 4.3*10-60. > A mass-murderer space rock happens about once every 30 million years on average. This leads to a probability of such an event occurring in the next second to about 10-15. That's 45 orders of magnitude more probable than the SHA-256 collision. Briefly stated, if you find SHA-256 collisions scary then your priorities are wrong.",
"Yes, in fact there are an infinite number of passwords that would match your hash. The thing is, hashes have been well tested and there are no short strings of characters (like a password) that match the hashes of other short strings of characters. So for example, there might be a string of letters and numbers 1 billion characters long that has the same hash as your password, but no one is ever going to discover that. You should spend your time worrying about stuff that is more likely to happen like winning the Powerball 5 times in a row while getting struck by lightning on your birthday."
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cqv6nm | How does binary code get such specific things done? I understand how binary can represent letters or numbers beyond 0 and 1, but how do you make it display things or tie them together? | Technology | explainlikeimfive | {
"a_id": [
"ewzti0a",
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"text": [
"Thinking about computers moving around 0s and 1s is probably the absolutely least helpful way of understanding anything they do unless you're looking at the lowest-level, nitty-gritty details of how transistors and logic gates are organized. What computers do is *operate on numbers*. Those numbers, internally, are 0s and 1s (or high & low voltages) but you almost never look at a single bit in isolation, you've got a \"chunk\" of them. For most purposes seeing the 8 binary digits \"00101011\" should be understood as the number 43 because they're all passed around as a single \"chunk\" of data that doesn't get split up. Want to do math? You can do math on them. Want to store text? That's the 43rd character in whatever character set you're using (\"+\" in standard ASCII). Drawing a picture? It represents a pixel with color #43 (imagine a big paint-by-numbers thing). Want to access main memory? You use numbers as addresses. Want to have program logic? It represents the 43rd different instruction your CPU understands.",
"Going from 0s and 1s into a working functional computer is quite complex and the topic of many collage courses. The CPU reads numbers from the memory and interprets them as instructions. It does this by looking up this number in the microcode to find a much bigger set of 0s and 1s that is control signals for the CPU. These control signals will individually go to different components of the CPU turning on or off different transistors. For example you might have a set of transistors which will let the signal from bus A enter register EBX if it is given a control signal. All the different components of the CPU like add, multiply, store into memory, etc. is defined using fixed transistors connected together and controlled with these control signals. When the clock gives a signal to the CPU it will trigger other transistors to update the control signals. Some instructions will make the CPU change where in the memory it retrieves the next instruction from. And these can be inhibited by certain conditions in the CPU. For example it can look at a register and if there is only 0s in the register it will update the instruction pointer, if not it will just increase it by one like any other instructions. Using this we can build logic into the set of instructions and have it do different calculations based on different data. And this is how we can make machines \"think\"."
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cqvh2v | When we upload our card details when shopping online, is there any mechanism/system that ensures that the vendor retrieves the exact amount which is shown us? | It seems like such an act of faith when you upload your card details. I always feel like the vendor can take as much as they want, either maliciously or accidentally. What's the chance of that happening? | Technology | explainlikeimfive | {
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"It's all encrypted and automated (assuming you're on a legitimate e-commerce site) so while glitches happen, it's extremely unlikely. And, if it does happen, your bank and the retailer will do whatever it takes to make it right. To not do so would be disastrous for their \"brand\" (and potentially illegal)",
"When you put in your \"bare\" card details: Pretty much only your card's daily limit (if present) and you reporting the fraudulent charge after you notice the theft. This is why you avoid those sites like the plague and use PayPal (or similar, or if your bank, like ones in my country do, operate a similar secure payment site, that) as a single trusted buffer between you and the shops. Not only because of the danger of the shop itself stealing your money, but because of the danger of the shop storing your card details (even for something benign like \"pay easier with one click next time\" features) and then getting their ass hacked and card data making it into the wild."
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cqvru5 | End to End Encryption | More specifically, how is it possible for one entity to create a cipher, use that cipher to encrypt information and then send both the encrypted information and the means to decipher that information over it’s own network and still claim that it does not have the ability to view or modify the original information. | Technology | explainlikeimfive | {
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"The actual answer is _way_ beyond an ELI5, but the general gist is that there are the special kinds of math equations that only really work one way - you can put a number into the equation and get an answer, but you _can’t_ run the equation in reverse, putting the answer in and getting the original number back out. The only way to get the original number from the answer is to put it in a _second_ equation, which is designed to turn answers into original numbers. If you want to know how that works, you’ll need someone else to explain it, but for now just trust that this is a real thing. Now, since we have a pair of equations that can turn numbers into answers that the other equation can turn back into numbers, we have the core of public/private key encryption. You can publish one of the equations - known as the public key - and let people use that equation to encrypt their data. You retain the other equation - known as the private key - since it is the only equation capable of _decrypting_ the data. Thus, data can be encrypted by _anyone_ using a cipher that only you can decode. Once you have that initial data transfer accomplished securely, you can set up different, bidirectional encryption for other data transfers back and forth. The awesome part of this is that it works in reverse to. You can encrypt something using your private key that only your public key can decrypt. This allows you to verify to others that you are who you say you are. You publish the public key for the entire world and then publish a bit of data encrypted with the private key. Anyone can take that data, decrypt it with the public key and verify that you are the holder of the private key, and thus are who you claim to be.",
"If Bob encrypts a message, and writes it on a piece of paper, and gives the piece of to the Post Office (where Eve works) to deliver to Alice - it's pretty clear that Eve can't read the message. Your second notion, sending \"the means to decipher that information\", is a little less clear. Bob can write \"use Key #3265\" in plain text on the envelope containing the piece of paper. That gives Alice information she needs, but which Eve can't use unless Eve also has a copy of key #3265. Now if Bob were to write \"use the key 12X4\" on the envelope then \"anyone\" could read the message, including Alice and Eve. This wouldn't be a very good solution, and it's hard to think anyone has proposed this as \"secure\"."
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cqw6vf | How do huge companies keep their upcoming products from getting leaked (most of the time)? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"NDA's and the fear of losing ones job is usually enough. Unemployment sucks and is one of the most stressful periods in one's life. There's work stress and then there's the stress of not knowing if you can pay this month's bills."
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cqxkfr | Power BI, Salesforce, Microsoft Dynamics, SAP - I’m unsure who does what and the roles they have | Can you please explain? I’m completely lost. Thanks! | Technology | explainlikeimfive | {
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"Let's say you run your own business making and selling widgets. You need to keep track of who your customers are, your customer contact list. You need to record the sales you've made, generate invoices to send to customers so they know what they owe you, and record when payments are made. That's Customer Relationship Management. CRM is a type of software you would use to manage your customer interactions. But you also need to keep track of your widgets. How many do you have in stock, how many might you need next week, how many widgets can you make each day, how are you going to deliver them to the customer on time. When the customer orders widgets on your website, that order has to come to you so you can pick and pack the order, arrange for a courier to deliver it. Your business grows, now you have to build a widget factory and a warehouse and hire staff to help with everything. The widget factory has machines that require constant maintenance, replacement parts. You need quality assurance to ensure each batch of widgets works properly. Christmas is coming up and you need to increase widget production and hire more temp staff. You have to manage your property costs, staff wages, asset costs, staff scheduling. You want to make sure your business costs are less than your sales revenue. This is Enterprise Resource Planning. ERP is a type of software used to help manage all your business processes. Or even simpler: you're a plumber. You have your customers' phone numbers stored in your phone. That's your CRM. You book your customer appointments into a diary. In the same diary, you also keep notes about spare parts or new tools you need to order. That's your ERP. Salesforce is a CRM. Dynamics and SAP are ERPs. In reality there's lots of crossover of functionality. Most ERPs will have CRM functionality. Some CRMs will have some limited ERP functionality. PowerBI sits apart from the others, it's a Business Intelligence product. Basically, it's fancy reporting. So you might use it to do some reporting or analytics on data gathered from Dynamics, Salesforce, SAP and other systems. All the other products have some degree of reporting functionality, but BI tools like PowerBI can do it better."
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cqz1gu | What is 'Simufilming' and what was the purpose of changing the frame rate in old movies? | This is in reference to the Wiki article for [South Pacific (1958)]( URL_0 .) It has to do with changing the frame rate of the film from 30fps to 24fps 'thereby eliminating "simufilming"' what was the purpose of doing this? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"\"Simulfilming\" means filming the same things on two different cameras at once. Originally, there were several standards for film- most used 35mm film at 24 fps, but there was also a \"high definition\" format, which used 70mm film at 30 fps. In order to get the two different frame-rates, the two different formats would be filmed at the same time, with the cameras stacked together- one filming on 70mm at 30fps, and the other on 35mm at 24fps. What \"South Pacific\" did that was new was change the standard for 70mm films to 24fps (and also work out the technical details needed to do this). That way they could film with a single 70mm camera at 24fps, then they could just make smaller prints at 35mm for the other theatres. When doing analog films, it's easy to shrink or grow a picture when duplicating the film, using lenses. Changing the frame rate is very difficult, since someone would have to manually cut out the extra frames (to go from 30- > 24) or duplicate some of the frames (to go 24- > 30)."
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cr25tw | How were film effects done before computers? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Stop motion cinematic photography. Over lapping film. Model scale filming. That’s for starters"
],
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3
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cr29rn | How was film editing done before computers? | Technology | explainlikeimfive | {
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"Sound effects and audio work could be done with magnetic tape and analogue electronics. Freeze frames are just a simple matter of printing a single frame to multiple frames. On-screen text can be as simple as using a camera to photograph text produced by artists. Even the famous *Star Wars* crawl was done this way, with the text on a long scroll mechanically moved off into the distance. Burning in the text over other footage and/or matting it in front is a little more complex. For the most sophisticated work they might have had to resort to the same techniques used for animation, with layers of transparent sheets being photographed. Wipes and other transitions can mostly be done with double exposures somewhere in the post-production process. You use a sliding mask for the A- and B-roll that advances for each frame so that less A and more B is printed as the wipe progresses. Fades simply involve progressively reducing the A-roll exposure and increasing the B-roll."
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cr55vv | - the 2.4 and 5GHz channels on my modem/router. | What’s the purpose to have two channels to connect devices to? Is one more for phones/tablets and the other for PC/consoles? Does it matter? Should I split connected devices evenly or just overload everything onto one? | Technology | explainlikeimfive | {
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"A dual band router (one that can run on both 2.4 and 5Ghz) is beneficial for a couple of reasons. Your device is less likely to be affected by interference from other sources of radio waves as it can switch between frequencies. The second is that 2.4Ghz has a lower bandwidth (meaning less data transferred over X amount of time) but its range is greater. 5Ghz is the opposite of this. It delivers info faster but its range is shorter because of the higher frequency.",
"2.4 has a greater range. However for most people that extended range is negligible. 5ghz however has a wider array of channels and would allow you to better setup your wireless network in a crowded area. It also has a higher bandwidth. So what does that second bit mean? Well, each of these signals have various channels (like in the old days with over the air tv). Your wireless access point can broadcast on these channels. However everyone else’s wireless access point can also broadcast on those same channels. This can cause your connection to get scrambled up in all the waves jumping around in the air and result in a weak signal. By selecting a channel “isolated”* from others, you can get a clearer signal. *to clarify this. If everyone broadcasts on channels 2, 3, and 4, channels 1 and 5 (or more) will still be impacted slightly. Channel 10 is far from that though.",
"All the other explanations are good, 2.4GHz longer range, less bandwidth, but can congested even if your nearest neighbor is 5 miles away. There are a lot of devices that use this frequency like:baby monitors, cordless phones, car alarm movement sensors, mics, wireless controlled lights(ZigBee), poorly shielded microwaves, and the big killer wireless video cameras that can kill 1/2 the 2.4Ghz band. What the others do not mention is the newest WiFi protocols can use all the bands between 1 and 7GHz including 2.4 ang 5 GHz. This allows for longer range with the lower frequencies and higher bandwidth with higher frequencies. Combine them all and there is 11 Gbps possible with much less latencies(1/4 of 802.11ac). There are a lot of tricks used to increase the bandwidth like using not just the direct signal, but at the higher bands using the signals that bounce off walls and other paths that are not direct"
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cr7jx6 | How are mobile devices powerful enough to send data? | How does a mobile device (eg: Smart phones) send and upload information and data to the internet? I’m aware that mobile data received comes from the transmission from local masts and aerial transmitters, and that the cellular device will have som kind of receiver within, but how on earth is the phone powerful enough to send requests for information to whatever local receiver is required to connect to the internet? Unless the whole process is being misunderstood by me. | Technology | explainlikeimfive | {
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"First, the cell towers have a pretty big receiving antenna themselves. Even if your cell phone sends out a relatively weak signal, the cell tower can collect a lot of that signal. Second, your cell phone sends that information on a very narrow frequency band. Cell towers have electronic devices called filters that take all of the incoming electromagnetic noise, and only looks at a particular frequency. Your cell phone might not use a lot of power, but that power is very concentrated in that particular frequency",
"The current QRP (from telegraph Q codes meaning \"What is your power output in watts?\") world record (so we're talking about Morse code communication) is 1650 miles on the 10-meter band (28-29.7 MHz), from Oregon to Alaska, on 1 micro-watt of power. & #x200B; There are lots of impressive records and examples of just how far you can transmit a loud, clear signal with next to nothing, but I won't bury you in them. & #x200B; There are 3 major factors you can contemplate in what is called \"signal propagation\". First is frequency. Low frequencies travel further without being absorbed into the environment as heat. Your WiFi signals from your home network and devices were chosen at 2.4 GHz because water absorbs that energy, so do wall panels, trees, etc. That way, the whole world and outer space doesn't need to receive your Reddit browsing radio traffic. The second factor is power output, which increases the amplitude aka volume of the signal. Your devices could simply shout, you could be heard further away as you overcome your signal being absorbed into the background. The third thing you can do is get a bigger antenna to listen to really weak, really faint signals. There are some antenna that cleverly span the whole planet so we can perform some radio astronomy shit. Satellite dishes have a geometry to catch a faint signal across it's surface, and then reflect that toward a single point, where the receiver is, which is where the actual antenna is. Concentrating a signal like that is effectively boosting it's amplitude out of what little there still is. & #x200B; So it's a combination of the frequency chosen, the power out, and the antenna listening. Towers have lots of power and can shout from high places, but have big receivers to hear the cellphones responses."
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cr9gd3 | why do CDs tend to have a higher quality than digital streaming like YouTube and Spotify? | Technology | explainlikeimfive | {
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"Because streaming generally is compressing the data to save bandwidth, which degrades quality. Also more and more people tend to stream over bluetooth, which can also cause an additional drop in quality depending on hardware.",
"Because they store millions of songs they have to compress them more to save data center storage. And to reduce overall traffic. On CDs there's no need for traffic or download speed. Some services actually allow listen or download WAV, but it's usually when you buy a song."
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cr9zae | 4G cellphone service used to be the best option we had, and though it may not have been lightning fast by some standards, it still got the job done. Now that 5GE is available, having 3 bars of 4G can’t even load an internet page sometimes. | Technology | explainlikeimfive | {
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"For now, \"5G\" is more hype than reality with most areas and providers, and \"5GE\" doubly so. It's unlikely to have any impact, positive or negative, on your experience. As for why your 4G data connection may be poor, the most likely reason is that the tower you're connected is overloaded. The \"bars\" shown on your screen represent the strength and clarity of the radio signal connecting your phone to the tower, not the speed of the data transfer through the tower. If too many other subscribers in your vicinity are downloading/streaming data from the same tower, the *tower's* connection to the Internet -- the backhaul -- may not be able to keep up with everyone, even though your connection *to the tower* is clear and strong. For your purposes, the bars represent how likely it is that a text message, or voice call, will get through without being dropped. Calls and SMS messages are less demanding, and more highly prioritized, than data. Some of this is due to the fact that pretty much everyone has a 4G device by now. The odds of a 4G tower being congested are a lot higher now that everyone is using 4G.",
"There are a few things to clear up here Signal strength is not equal to internet connection speed. The bars merely indicate how strong the signal is, not that a tower has time to serve you data. Think of full bars but limited data like a waiter in a crowded but quiet restaurant - you can hear him just fine, but he reallyyyy doesn't have time to bring you your drink 4G ***LTE*** is still the best network connection you can have. A few months ago your phone would have shown LTE normally and 4G on slower towers. Now AT & T rebranded 4G LTE as 5GE. When you see 5GE it's exactly the same as when you'd see LTE a few months ago, absolutely nothing has changed but the label",
"Honestly, install an adblocker extension or browser that natively supports ad (and tracker script) blocking. The decrease in data usage and speed increase in page loads is shocking. But basically, nobody bothers to code their sites for efficiency anymore because 'they'll be on wifi anyway' or 'it works on the newest iphone fine.' Largely because nobody wants to pay what it costs for a proper developer to take their time and work towards efficiency."
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crarrw | The difference between a router, switch, hub, a bridge and a modem | These are all networking devices that I constantly hear about but I don't know what they do. And no matter how any webpages I visit, I still leave more confused than when I originally went looking. | Technology | explainlikeimfive | {
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"Edit: Network traffic broken into packets, which you can think of like a letter in an envelope. The letter is your data (like a Google query) and the envelope has a 'to' and 'from' line to help know how to forward it on. All those devices have different techniques for knowing how and where to forward an envelope onto, once they get it. **Hub:** Make a copy of a letter and give it to every one of your neighbors with a t-shirt cannon, whether you meant to give it to them or not **Switch:** Make a copy of your letter and use a map to drive it to a specific neighbor **Bridge:** When you want to give a letter to Billy the next neighborhood over, so you give it to his brother who lives right in-between the two neighborhoods **Router:** Send your letter to the post office, and they'll send it to your grandma by forwarding it to her post office and then driving it to her house using a map **Gateway:** The post office in your neighborhood **Modem:** Send your letter to the post office by saying it over the phone to a postal worker, where they type and print it off and forward it on",
"**Router:** Directs network traffic based on destination addresses and preset rules. These are usually situated between gateways/modems and switches. **Switch:** These devices simply connect multiple devices together, sort of like a splitter. Although managed switches can do quite a bit more, such as create VLAN's, which can help organize and protect network traffic. **Gateway:** These are often times mistakenly referred to as modems or routers. They are devices that connect a private network to the internet. However they can also just be a device that connects one private network to a larger private network. A residential gateway is likely the device you have at home that connects you to the internet. **Hub:** These are essentially the dumb versions of switches. They function like repeaters, so when a computer talks on the network, the hub will broadcast that message to every port on the hub. If the message reaches the target PC, then that PC will do the same. This is a very inefficient method, which is why hubs are obsolete. Switches contain memory, so they remember which PC is on which port, and will direct messages to the correct port without having to constantly broadcast to all ports. **Bridge:** A network bridge joins two networks together. Such as one PC sharing the network connection with other PC's. Things like transparent bridges create a seamless link, these are often times used by security devices such as firewalls. They will inspect network traffic and block anything that violates the rules. **Modem:** A device that converts network traffic into a format that can be used on the media that connects you to the internet; Whether that be fiber, coaxial cable, 3G/4G wireless signals, or a copper phone line. & #x200B; Edit: What you have at home, which is often times referred to as a 'Wireless router', or just a 'router', is actually a combination of a lot of these devices. They are indeed routers, but also switches, wireless access points, and sometimes modems/gateways. If it contains a modem, it can be referred to as a residential gateway, if it doesn't, then it's a wireless router. Small businesses will often use these same devices, but larger businesses will use enterprise class hardware, where these devices are separate and usually mounted in an equipment rack.",
"Hub: Everybody yells in your house whenever they want something, it sucks, plus now everyone knows everyone else's business. Nobody yells anymore, hubs are bad. Switch: If you want to yell at someone in your house, you go to them and yell at them, nobody else hears it. To yell back at you, they come to you. This is awesome but still local and indoors. Router: You want to yell at your neighbor but don't care where he is, these take the noise and pass it around all the way to his ears. Bridge: It's like that door that connects two rooms in a hotel so the family can yell at each other. Modem: It converts the yelling into electricity so your yelling can travel far and reach your neighbor (you don't know/care where he is, see router above)",
"Your ELI5 answer: Modem = where internet comes from Router = routes internet to devices from modem, usually creates wi-fi Switch/hub = same as router just more dumb/less features Bridge = Used to cross a body of water, or to connect two connections into one. & #x200B; edit: a lot of people don't understand what ELI5 means",
"Router = A call center phone system where everyone can only be reached through an extension from the main line. Hub= a friggin mega phone. Literally.. Imagine every phone call received by a call center just get blasted out on the entire floor. Switches=Everyone gets his own direct phone line in a call center. Bridge=Two completely different physical call center locations using the same main phone line. Modem=Modem is more like a translator. It's a magical translation machine that can turn all the calls from Japanese speakers into English. That's the best ELI5 I can think of.",
"Oooh... one I'm qualified on! Let's say you have a room full of people who want to talk. Every time you need to communicate with someone, you YELL their name as loud as possible to make sure everyone in the room can hear: \"HEY! JOE BOVINGTON! I HAVE A MESSAGE FOR YOU!\". If you hear your own name yelled, you listen to the message after... otherwise you just ignore it. If you and someone else both start yelling at the same time, you both shut up for a random amount of time, then try yelling again. That's a *hub*, complete with collision detection. I'm sure you can see some downsides. So how do you fix that? Well, imagine another room at a fancy party. Each time someone enters the room they announce \"JOE BOVINGTON HAS ARRIVED!\", then shut up. If you want to talk to Joe, you now know he's here so you ask the butler (who keeps track of these things) where he's standing, and you go have a private conversation. That's a *switch*. It's much better - you're much less likely to accidentally talk at the same time as some else, and if you do, it doesn't matter. Next imagine you have a real banger of a party that takes place in two different rooms. If you put a doorway between the rooms so that all the chatter in one room echoes down the hallway to the other room, that's a *bridge*. A bridge makes multiple, separate physical networks into one logical network without providing any routing. Finally, let's imagine I have a massive block party going. There's parties at every house on the block. I need to talk to the same old Joe Bovington, but my butler doesn't know where he is. There's a creepy old guy on neighborhood watch, though, who knows exactly who's in every single house. So I go ask him if he's seen Joe, and he sends me to the right house. Once I'm there I ask the butler where Joe is, then have my conversation. That's a *router* - a device that will bounce traffic between different logical networks. A modem is comparatively simple: Turns out Joe only speaks Australian English, which is utterly incomprehensible to anyone civilized, so I have a British friend translate. That's a *modem's* job - translate between one or another data format.",
"The best way to imagine these concepts is to imagine the old telephone system back in the day where we used to have actual human switch board operators. Firstly, imagine everyone in your neighborhood had a telephone, and they were all physically wired together. Sure, you could reach anyone in your neighborhood but only one person would be able to speak at a time, and everyone who was on the phone would hear every conversation even if they weren't involved. And everyone would have to try to compete for talking time on the same line. This is a HUB. Now imagine that everyone in your neighborhood has a phone, but instead of them all being physically wired together, they all go to the central telephone company office. When you pick up the phone, you reach the operator at the central office. You then tell the operator who you're trying to call and they connect your call using a wire between your phone line and the recipient's phone line on a switchboard. This is a SWITCH, since they are 'switching' your call to the recipients line. Multiple people can use their phone lines at the same time without having to wait their turn to speak on a shared line, and nobody else is subjected to your conversation. Only the 3 parties are involved; caller, operator, and recipient. The simplest definition of a bridge is that it physically connects devices on a network. So in the previous example, the wire that the operator used to connect your call? That's a BRIDGE. So both hubs and switches are technically types of bridges because they physically connect the phones together. However, in most cases, a bridge is used to connect physically diverse networks (think electrical < - > fiber optic, or wired connection < - > wireless connection). This is all fine and dandy, but what happens when you want to call someone in a different neighborhood? Sure, we could connect all of the neighborhoods together into one big switchboard but that would get messy. When you reach the operator and tell them you want to connect your call to someone in a different neighborhood, they will route your call outside of the local telco office for your neighborhood over a network to the operator at the local telco office of the person you're trying to reach. Your operator, and any operator in the network between them and the destination operator are now acting as a ROUTER. Now let's say for some reason you were in a neighborhood that was still stuck with telegraphs and didn't have phones yet. But the person you're trying to reach doesn't have a telegraph, and even if they did, doesn't know morse code. So you telegraph your operator, who then translates your telegraph into speech and carries on the conversation for you, and translates the replies back into morse code and transmits them back. Your operator is now acting as a MODEM. A modem is also an example of a bridge.",
"First of all, all comunication between computers happens in the form of little information packets of zeros and ones. A hub can be used to connect multiple computers on a network together. When it receives a packet on one of its ports, it will send a copy on all other ports. This means everybody else on the hub gets the packet, even though only one of those connected machines is the actual adressee. A switch is slighly less dumb than a hub. It learns the addresses of all machines on its ports, and only sends packets to the proper receiver. A gateway is a computer that is connected to two networks. It can send packets from ond network to another, creating an “internet”. A router is a very big switch on the global Internet that sends packets roughly in the right direction, even if it doesn’t directly know the recipient. A modem is a device that can send packets of zeros and ones over an analog medium (a phone line, a glass fiber cable, etc.)",
"* The modem converts (or MOulates/DEModulates) the digital signals (1/0) to an analog medium like sound or light and back. *ELI5 A 2 way radio modulates and demodulates sound to/from radio waves in the air.* * The hub connects Ethernet lines together and repeats the signals so all the lines can hear each other. It forms a small network. *ELI5 A room with a big computer screen and everybody has a keyboard Anybody can say something by typing onto their keyboard, and everybody else can see it. If too many people type at once, it's all gibberish.* * A switch is like a smart hub. It connects Ethernet lines together, but it acts like a traffic cop, and can segment out connections. It can form bigger networks *ELI5 - Same room as above, but everybody has instant messaging and their own screen & keyboard You and your friend across the room can text to each other without bothering everybody else. You can have multiple chat sessions and chat with anybody in the room. When you need to talk to more then one person, you can setup group chats and send a message to many people at once* * A router is like a switch, but even smarter. Instead of just connecting Ethernet lines together, it can connect multiple networks together. *ELI5 - Your messaging system above, can now be used to text people in other rooms*",
"Hub: It take the incomming data and send it to all the ports as it come. If two device try to talk at the same time then a data collision occur and the two packets are lost. Each sender will then wait for a random delay before trying again. Hopefully this time it will pass. The 'looser' will try again later on. Switch: It is an intelligent hub. It have memory and a processor. When it get a packet, it store it in memory, then read the source and destination address, write the source address in memory with which port it came from. Now it look in the table to see if there is an entry for the destination address. If yes then it will send the packet on that port only, if not then it will send it to all ports. When it receive a reply, really, it is nothing else than another packet, so the same logic apply... Read source and destination address, write source in table with the port, send to the destination port if known, or on all if not. Modem: MOdulator DEModulator. Really, it is a media converter. Back in the old day, it was a serial to phone line converter, then it became some cable modem or DSL modem, or fiber optical modem. Really, it change one format of data communication to another, while passing the same data. It is more complex than this, but that is the important part. A cable modem will convert ethernet to radio frequency and send it over the coax. It also do the reverse. Router: This is not what you have at home that you call a router. It is a device that connect multiple network together and route the packet to the right network. For example, your ISP have most likelly a few links to different providers. The router would decide where to send the packet. For example, it could have a direct link to the google network, level3, bellnet and sprint. You try to access a server, it will take the packet and decide where to send it. Ex: \"this link is expensive, the other less expensive one are free, let's send it to the cheaper one\" \"This packet goes to google, and I have a link to google that is working, let's send it there\" \"This packet should go to link 1, but it is broken right now, so let's use link 2\"... DHCP Server: It assign an IP address to each devices on the network. Your \"router' is a NAT with a DHCP server and other goodies inside. Your device broadcast a request for an ip address. The DHCP server reply with a private address, usually in the 192.168.0.x or 192.168.1.x range, but other are available but less common. In short, each devices now have an unique address on the network. Except that they are private address and unroutable on the internet, as they ain't unique worldwide. But they are in your 'bubble' of devices. NAT: This is what you call a router. Network Address Table. It screw up with the packet header to change the source and destination address and take note of the real ones. The problem is that your ISP gave you a single address for ALL of your devices. This can not work as each must have it's own address. This is where the NAT come into play. The DHCP server gave some local address, the NAT have the public address and a local address. When a device want to talk to one on the internet, it will forward the packet to the NAT, which mess up with the source and destination address. On outgoing packet, it replace the source address from the local device, ex: 192.168.0.100, to it's own public address, let's say 24.200.100.6. This public one is routable on the internet, So it send it and take note of the info to track down the connection. The server reply back, send the data back to the NAT. Now, the NAT take the packet, replace the destination address by the local address of the device and send it on the local network. If it get a packet that do not match any of the connection it track, then it just discard it or reply with an 'error' packet as it do not know what to do with it. Gateway: it bridge two network together. For example, you can have a 192.168.0.x and a 192.168.1.x network. Each other can't talk to the other group. However by talking to the gateway, it can forward the packet to the right group.",
"You are passing notes in the classroom. When passing notes using a hub you make a copy for everybody in the class, the people who it isn't for ignore it unless they are nosy. When passing notes using a switch you walk over to the person and give the note to them. A bridge is if you open a door into another classroom, the note is given to the classroom where the recipient is. Then it is delivered according to whether that classroom is a hub or a switch. You can't connect more than two classrooms with a bridge. A modem is if instead of carrying it by hand like normal you put it on a drone and fly it across the classroom. A router is a person in the hallway who knows all the classrooms in that hallway. You want to send a note to somebody but they aren't in your classroom, so you give it to the router. The router then gives it to the classroom it is supposed to go to. A hallway can be really simple, your classroom and a door to another hallway. If the note is not for your classroom then it goes to the other hallway. Or a hallway can have doorways to hundreds of other hallways and all the people in the hallways talk to each other about which classrooms are in which hallway. Finally there is a thing in most people's home which people call a router but it is usually actually three things. A switch, a router, and a modem. The switch is the classroom for your house, notes are passed directly between the computers in your house. If a note is for somebody not in your house it is given to the router in the hallway between your house and your ISP. However the hallway is really long so instead of walking back and forth to deliver messages there is a high-speed conveyor belt which runs up and down the hallway, the modem handles taking messages on and off of the conveyor belt so the router can handle just the messages.",
"So one of the first things to understand is data packets and frames. Basically your data gets broken into chunks, then each chunk is wrapped up in a header/trailer. Which is basically sticking it in a box and putting labels on it. Then that box gets stuck inside another box which gets it's only labels and information. This happens several more times. Each layer (each box) gets a different name. The final box is called a frame. This is everything all wrapped up and ready to actually send from one device to another. The important information here is that a frame has a MAC address (Also known as a physical or hardware address.) Every piece of hardware has a (mostly) permanent address randomly assigned to it. Your phone, your PC's ethernet card, your PC's wifi card... all have a unique MAC. Switches and hubs care about frames. They read that MAC and send out the frame to it's destination. a Hub is dumb.. it doesn't know where that's gotta go, so it just sends it out over EVERY connection it has. It'll get to the right place eventually right? This created a lot of extra data and slowed down networks, so we created switches instead. Hubs should almost never be used in today's networks. Switches are smarter. It looks at that frame, reads the MAC address and knows exactly which connection to send it out to get where it's gotta go. So if that PC is plugged into port 2, it ONLY sends that frame out port 2. Switches have a list of every MAC address plugged into them... and share these lists with other switches on the same network. So if your PC wants to send a frame to Bob's PC... but Bob's plugged into the 2nd floor switch, your switch goes \"I need to send this to the 2nd floor switch first.\" THen the 2nd floor switch figures out where to send it. But there's billions or trillions of MAC's and they're almost entirely random. There's no way a switch could know and process every MAC in the world. So your switches only know things on your local network. They don't worry about things on say, Google's network. So we have routers/gateways/bridges. These devices actually open up that frame. They peel away the outer layer and look at the next one. Basically they open up the outer box and read the label on the one inside it. This is called a packet. Packet's have an IP address. IP addresses are important because they're logically assigned. This means we give them out based off logical, organized concepts. So for example, every device on your home network has an IP assigned to it that probably starts with 192.168.0.x. The router knows that anything that starts with that, will be on your home network. However if it has a packet for say [8.8.8.8]( URL_0 ) (google's server) it knows that gets sent out over your internet connection. It doesn't have to know exactly where that server is... just that anything that starts with 8.8.8 is definitely out over the internet. Your ISP has massive routers that can point exactly where that's at. In a home environment routing is simple. Everything with 192.168.0 goes inside the network. Your router has a list of internal IP's matched with the MAC address to the device. So it wraps the packet in a frame and throws it at the switch to get it where it has to go. ANY other IP address, it sends over your internet connection. So basically it looks at a packet and says \"Do you have a 192.168 IP? If yes, inside you go to the destination. If no, then I'm going to chuck you out to the ISP router, you're his problem now.\" In a corporate environment this is waaaay more complicated. For various reasons you may have departments/floors/builds/devices on different networks. So I may have floor 1 on 10.1.x.x network, floor 2 on 10.2.x.x. Floor 3 on 10.3.x.x and an outbound internet connection. But I want those networks to still talk to each other, so that Sally can send a file to someone on the third floor. So the router has a more complicated job. It looks at a packet and says \"If you have 10.1.x.x, i'm sending you to the first floor switch that's connected to port 1. If you have 10.2.x.x I'm sending you to the second floor switch connected to port 2. If you have 10.3.x.x I'm sending you to the third floor switch connected to port 3. And if you have anything else, I'm sending you to the internet connection on port 4.\" Routers know this because they have route tables. Basically it's a list of IP addresses... or groups of IP groups. Each one has a port assigned to it. If the IP matches, then it knows \"Shove that data out this particular port.\" The reason IP's are so important is because we can group them up since they're logically assigned. So because we can say things like \"All these computers over here we're going to give IP's that start with this... those over there all start with that.\" we don't have to list EVERY IP address with a route. We can group them :) Switches can't do that with MACs because MACs are pretty much random. Modems are short for Modulator Demodulators. Hence Mo...Dem. What it does is convert digital to analog signals and back. So most switches and routers use digital signals. Electricity over the wire is either on or off. However older technologies, like phone lines and coax cables (Your cable companies wires) use analog signals. The electricity is always on... but sometimes it's high, sometimes it's low, sometimes it's in between.... So a modem says \"Okay how can I take this digital signal coming out of the router... and send it over this wire as analog.\" It's literally just a translator for different types of signals :)",
"For a somewhat better ELI5, you can compare it to the post office. I've used this with my kids and it seemed to click with them. Modem - stuffs your letter into an envelope, puts your name, address, and ZIP code on it and sends it out to be delivered. When you receive mail, it takes it out of the envelope and tells the correct program that it has mail. Bridge - Special trucks that deliver mail between two different post offices that have agreed to this setup. Might be more efficient in larger cities with many ZIP codes. Hub - If you're sending out mail, the post office makes a copy and sends it to every postal worker at that office and asks them if they know where it's supposed to be delivered. The ones that don't deliver that mail will throw it away. Terribly inefficient. Switch - A more efficient hub operating on the specific addresses for a given ZIP code. They receive the mail and consult the postal worker schedule and give it directly to the worker that delivers mail to that address for that ZIP code. If the mail goes to another ZIP code, it will send it to the next mail sorting center up the chain, leading us to... Routers - A mail sorting center, primarily they would handle transporting mail between different centers, any post offices they are directly connected to, and maybe some individual addresses. They operate on a ZIP code basis. They keep tables of the closest zip codes and route mail accordingly. If they don't serve a particular zip code, they send it to a default mail center where another ZIP code check with happen, and so on until the mail is finally delivered.",
"We'll go in order of use. You're on your **device** be it a PC, Pad, phone, TV, etc... A **Hub** is a piece of hardware that connects devices together and enables them to talk to each other provided that they are speaking the same language. The problem with a hub is that when one device wants to talk to another device, it has to yell and a hub is like a room that has a limited volume. If 10 people are yelling to read this text file, it takes a while (milliseconds) to sort who is going to read this text file. If you want to yell a large file like a movie, it take a bit more time. A **Switch** is a piece of hardware that connects devices together and enables them to talk to each other provided that they are speaking the same language. The difference between a switch and a hub is that each port on a switch can tell instead of yelling what port to give a piece of information to. There's a thing called Half and Full Duplex which means it can send AND receive at the same time or not at the same time. A **Router** is a piece of hardware that sends information where it needs to go. It has a 'schedule' called a route table that knows what destination a piece of information needs to go. What is vital for this to work is for all the devices to have an IP address that is within this route table. The IP address configuration has 3 major components. The **IP address**, the **Subnet Mask**, and the **Gateway**. The Subnet mask is like a Venn diagram that contains a network. It can be 1 device up to 4 billion devices. If the device is given instructions to send information outside of it's **Subnet Mask**, it gets sent to the **Gateway**. The **Gateway** is exactly what you think it should be, a **Gateway** to a larger world. The **Modem** is a piece of hardware that takes the information and converts it, think Star Trek transporters, into little envelopes meant for the carrier and sends this information along the way to be received by the rest of the network hardware along the way to its destination. Modem is short for Modulator/Demodulator and it Modulates the information to send out and Demodulates when it receives back into packets. A **Bridge** is a way to connect to remote networks as if they are local and the same network. Like Chicago to New York and so forth. Bridges were popular when you were pushing data over the cloud, not the could we have today but an ether of network data that was just 'out there'. Frame Relay over Cloud was the way you would Bridge networks together. Today VPN handles all that."
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crcmq2 | Why is the "T-Pose" the default pose used when animating 3D models? Why is this pose easier to work with then others? | Technology | explainlikeimfive | {
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"The \"T-Pose\" isn't easier to animate with, the reason it was used it because it kept joints in the body away from other joints in the body (ie the upper arm bone, or humerus, is a good distance away from the spine bone, etc). This was useful for a couple reasons. For motion capture it allowed you to determine bone position without overlap and it was very easy to see if things were out of place. For skinning (when a cg model is bound to the skeleton in the computer) it was useful to prevent bones that shouldn't have influence over certain parts of the skin from having an influence. As an example, again think about the humerus and a spine joint, if the arm bone is closer to the geometry of the side of the chest than the spine bone, the computer would add the point on the chest to be influenced by the arm instead of the spine (or perhaps ribs if they are being built into the skeleton). & #x200B; The full \"T-pose\" is not used as much anymore because the position of the shoulders and elbows are in a pretty extreme position when fully extended and raised. This cause issues with deformations, as the further away from the default pose you got, the more deformation there was, which typically meant more error. Usually these days we use the \"A-pose\" which has the arms down at about a 45 degree angle and the elbows slightly bent and sometimes arms slightly forward. This keeps the joints away from each other as the \"T-pose\" did but means that the shoulders and elbows are in a more mid position so that is the shoulders, for example, are raised or lowered they only have to move half as far as the \"T-pose\" to a fully lowered position. This of course has limitations, for example the human shoulder can actually more pretty close to 180 degrees, so the \"T-pose\" would seem to be more of a mid point, but in general every day motion the shoulders stay below the straight out position, so we usually build for the more common case and \"fix\" it in cases where the shoulders might rotate all the way up. There are other reasons for some of the positions of joints in a model (such as to avoid gimbaling), but the main reasons for the \"T-pose\" are the above ones."
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crcqkd | why do voices from robots/stuffed animals with sound chips break up when the battery is low instead of just dying? | Technology | explainlikeimfive | {
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"The voltage may be low enough that the sound amplifier \"hits the roof\" and starts clipping the top/bottom of the waveform off, or the battery may not be capable of supplying enough peak current to satisfy the amplifier's needs at loud parts of the sound."
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crd638 | How do internet routers store routing tables, even though there are billions of nodes in the internet | So the way i think routers work are that there are "layers", each router has a table which stores either the interface in which the computer is connected, or "someone" who has access to it. If the router has neither of these, then it is passed up to a higher "layer" through it's default option, this process is repeated until it reaches the root, where the packet is dropped if it still doesnt know. My question is, how does the internet as a whole store billions of routes, is there some sort of algorithm that decides where each route is stored, so that the first router initially knows where to send the packet, or is each individual address the only key that is used to find the path the packet will take. Also, how is the routing data "spread", does it cache the commonly used IP addresses exclusively or are the routes that are stored in the least significant routers some how pre planned with efficiency in mind? | Technology | explainlikeimfive | {
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"BGP - Border Gateway Protocol Core internet routers exchange known routes using a protocol called BGP. When a router is connected to the internet core it establishes a relationship with it's neighbors and presents it's known or connected routes to the rest of the network, and in exchange it receives all the routes known by it's neighbors and so on. If you think of routers as street intersections, each intersection only knows about the streets it's directly connected too. BGP allows an intersection to yell up the road to it's neighbor and say \"I have Pine street, and 5th avenue. What do you have?\" The neighbor responds \"I have 5th avenue, and Elm Street. But I also know about streets X,Y,Z from information I got from the next intersection over\" Using this information the router builds its routing table, think of this like a map that identifies which path to use to send traffic for a specific destination address. Routers don't route traffic based on specific destinations, only the network they are on. This would be like giving someone directions to your house, you give directions to reach your street first, you don't care about which number is on your house until you are driving on the street itself. Routers only care about what's directly connected to them (The other routers connected to its interfaces), once it identifies which route to take for a packet, it sends that packet to the next router up the chain and the process continues until it arrives at its destination. It's also possible for a router to learn about multiple different paths to a specific network. BGP has built-in mechanisms to determine which of these routes is the best path, and can fail over to another route if the ideal route fails. This however can require a tremendous amount of manual tuning to get routes to an optimal state, it's an art."
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crd86a | How do deepfakes work? | Technology | explainlikeimfive | {
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"It consists of 3 parts. Encoder, which turns image into bunch of numbers. Then two decoders, that both can take that number string and turn it back into a picture. You train it in two separate ways. First you plug encoder into decoder A, and feed it pictures of person A. You then train it to give back the same image. You do the same with decoder B, you plug decoder B onto encoder and feed it pictures of person B, and again encoder turns that into bunch of numbers, and decoder B turns it back into image of B. You then do some mathematical trickery to motivate encoder to use all numbers efficiently. You want each number to be surprising in a sense, which is the same as each number having high information value. This means, when you're training encoder + decoder A for example, you don't want to just use numbers to store pixel values, since pixels aren't that surprising: you know they contain image of A, so you for example can be fairly confident the dominant color of pixels is the skin color of A. How to enforce this surprisiveness is a bit technical, but it can be done. That way, encoder is forced to kinda ignore all common traits of A's face as they are not surprising, and decoder A is forced to learn those common traits and paint them back in even without encoded form containing information about them. This way, encoded form contains information like what way person is looking, angle of their face, their expression, etc, things that surprise the encoder about the face, but none of the details that are just regular part of the face. And both encoders learn their own face so they know how to fill that information back in. So if you use encoder + decoder B, but feed it a picture of A, the encoder throws away all the data about the face being actually A, but tells exactly the expression and that sorta stuff, which decoder B uses to obediently paint face of B in that exact pose. So you feed image of A, but get back image of B in the same pose, having the same expression, etc. So the trick basically is, you have decoders learn the traits of faces of A and B respectively, and you have encoder learn to throw away all that identifying information, so in the middle point, encoded form, where swap happens, there's nothing identifying remaining telling you if the face actually belongs to A or B. So you can decide which face to paint in by choosing appropriate decoder."
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crfetl | Joysticks (gamepads) no longer need calibration | When I was young (like actually 5) whenever I would play a game on my computer with a joystick I would always have to calibrate it. There would be a calibration section on every game where you'd move the stick to one corner then to the other. I can't remember the last time I've had to do this. It's been decades. Now controllers just work. What changed? | Technology | explainlikeimfive | {
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"Standardization and driver advancement. It's the same with voice chat and dozens of other features. Operating systems now integrate video game support into their core functions which allows the games to call on those standardized drivers rather than having each game developer writing their own interfaces for nonstandard drivers. But it's not just software. Now that the drivers have been standardized, gamepad and joystick manufacturers no longer create their own individual drivers, but build controllers to match that single standard."
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crgbxu | How do old videos/movies that are made with old technology get made into HD without being totally remade? | Technology | explainlikeimfive | {
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"These movies were recorded on film with negatives rather than to some kind of VHS-like tape medium. Each frame actually holds pretty high quality images. You can go back to the original film and re-scan the frames with higher quality digital equipment and produce HD videos from it. Any editing and special effects will have to be re-done since this is just the filming of the actors on the sets. But it's totally doable."
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crgv8g | How does a Pedometer (Step Tracker) app on a smartphone know how many steps I’m taking (and how many stairs I climb)? | Technology | explainlikeimfive | {
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"Combination of tracking your GPS movements and using the same sensors that check whether you want the phone in portrait mode or landscape to sense when you're stepping up and down. The latter is the same way your DS (if you had one) worked as a kid, and it was why you (me) could sit there for a few minutes and break the system by rhythmically moving your ds up and down a certain way to mimic walking. You could probably do that with your phone/watch.",
"While the device is on you and you are moving about, the accelerometer in the device generates data that gets fed into the processor. Software on the device interprets that data and categorize it as either walking, running, stairs, swimming, or other. While you are in that walking activity your movement patters are relatively consistent, so the software takes that pattern recorded and counts the patterns as steps. [This study]( URL_0 ), while not for 5-year olds, explains it in more detail. If you are interested in it."
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crh06q | I've been seeing all of these Deepfake videos and I just don't get what they are. Please help. | Technology | explainlikeimfive | {
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"It's face swapping for video, using an AI tool. They're edited videos - someone will take an original video with someone's face in it, and use a tool to replace the original face with someone else's face of their choosing. It works by taking a whole bunch of images of the original face in all sorts of positions and angles and lighting, and a whole bunch of images of the face they want to swap in, also at many different expressions/angles/lighting. The tool then uses that training data to determine what position/angle/lighting the original face is for each frame, and replaces it with a synthesized version of the face they want to swap in. Edit to add: The reason they're called \"deep fakes\" is because the type of tool used to do this uses an AI technique based on \"deep learning.\" Deep learning is a type of machine learning that uses a self-programming computer algorithm that works similarly to the way neurons in brains self-organize by changing how they connect to each other. It's called a \"neural network.\""
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crhjjn | How do defective genes cause tremors and other neurological issues? | I am watching the Netflix show Diagnosis and this little girl has a broken chain in her KCNMA1 gene that is causing her to have temporary paralysis. How is a gene causing this and how do you fix gene defects? Did the defective gene mess up the way her brain developed or does it cause an over production of something? | Technology | explainlikeimfive | {
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"Genes are sort of like your body's source code. The code comes packaged as a long string of molecules called nucleotides, on a molecular structure known as DNA. This string of code is passed through another structure which uses that code to assemble proteins. Here's a video of DNA being copied, to sort of give you a visual idea of how this works. URL_0 Here's a video of protein being assembled - it sort of folds up in sequence depending on the DNA/RNA code. URL_1 If the source code is bad, either from damage or from inheriting a bad copy from parents, the proteins that are assembled won't work properly. Their structure will be different from a protein that works correctly. In the case of KCNMA1, this protein is involved in creating one type of ion channel. Ion channels are structures in nerves and neurons that allow them to carry electrical signals. If there's damage to the gene, nerve cells won't be able to send and receive signals properly. If you want to fix a genetic defect, you would have to use something similar to a virus to \"infect\" cells and change the DNA to produce a \"correct\" version of the code. Actual viruses do something similar, but instead of adding a good copy or replacing a bad copy, they add code which the normal function of the cell uses to make more copies of the virus. Please note that this is a gross oversimplification, and I'm not qualified to really answer your question in detail. This is more of a question for r/askscience"
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crimtl | how would the ‘life is a simulation’ theory work? | Technology | explainlikeimfive | {
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"There is a distinct possibility that the entire universe we perceive is actually a simulation in some great computer. Evidence to support this type of theory is often very philosophical; for instance, if we assume that people in every universe build computers that simulate smaller universes (take video games as a primitive example), then it logically follows that the majority of universes are simulated. If you think of every single universe we know of; ours, and every simulated universe from video games to physics simulations, 99.999% of those universes are simulated. Therefore, the only real assumption that this theory makes is that it is possible for a sufficiently large computer to simulate our universe."
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crm2lg | How do compilers work? | Technology | explainlikeimfive | {
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"Assuming you mean in computer software engineering... A simple compiler can be fairly easily written from a literal interpretation of the language syntax rules. Generally the steps are: 1) Read the program as a series of \"tokens\", which are the individual symbols or keywords of the language. In the case of C (and I will be using C for examples throughout this post), the words \"if\", \"while\", and \"float\" are keywords and are a single token each. \"12345\" is a token representing an integer. \"hello\" would be accepted as a token as the name of a variable or function or something user-created. The \"(\" parenthesis symbol is a token by itself, so \"((\" is 2 tokens, but \" < < \" is not 2 tokens because that actually stands for the bit-shift binary operation. 2) Parse the input according to the rules of the language, order of operations for math, etc. This will collect functions into a sequence of statements, and those statements might be an if/else which themselves contain a sequence of statements within them, etc. This is useful because the order of operations rules are saved and kept. The result is an in-memory structure version of the program as a collection of actions taken and decisions made. 3) Convert this in-memory structure into assembly code. If you can convert each of your fundamental language constructs (sequence of instructions, if/else, math, loops, etc) into some CPU code by themselves, you can string them together and get a whole working program. Of course this is simplistic, but effective. Real compilers are way more complicated though. Performance matters a lot so they look for patterns in the parsed data and try to make the code more efficient. For example variables that are used extensively may be kept in the CPU itself rather than copied in and out of memory. Computer Science students could make a compiler for a language like C in a semester, but GCC version 8 has a main compiler EXE that's 23 megabytes large on my system. That's a lot of features and optimizations added over the decades and GCC isn't considered to be the best compiler out there in terms of performance. All this is considered to be the work of the main \"compiler\". Making a final EXE involves two more programs: the \"assembler\" which converts text-representation of raw CPU instructions into actual binary CPU instructions, and the \"linker\" which can combine multiple assembly outputs together and handle the DLLs and stuff needed to make a truly complete EXE. The \"compiler\" merely produces text CPU instructions, partially for debugging capability and examining the compiler's work, and partially because C allows the user to write their own assembly bits in the C file."
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crmriv | How do pacemakers actually work? | I know the basics, that it senses when your heart is low and then gives it an electrical shock, but how does it do that? How does it sense your heart rate, how does it give the shock, and how does the battery last so long? I just got one put in, so I'm super curious, if anyone can explain! :) | Technology | explainlikeimfive | {
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"I have had a pacemaker for about 3 years. Most of the time, I don't even know it's there! A pacemaker, under normal conditions, works along with the heart's normal rhythm. Most people with pacemakers don't have complete failure of the heart's natural pacemaker. In these cases, pacemakers are used to correct irregularities in conduction of electrical signals through the heart (such as left bundle branch block,) or for patients with an irregular heartbeat, to bring the heart back to a regular rhythm by sending electrical pulses as needed to the heart muscle. A modern pacemaker, usually of the ICD (implantable cardioverter/defibrillator) type, has a very powerful (for its size) computer that monitors the heart from two or more leads inserted into the right side of the heart via the subclavian vein in the left upper chest, the area where the device is implanted. There are currently three major manufacturers of pacemakers: Medtronic, Boston Scientific and St. Jude Medical. Much of the time (depending on the patient's heart condition and the device's computer programming), it sits and monitors. When an abnormality is detected, it makes decisions whether to send electrical pulses to pace the heart or, in rare cases, send a larger shock to remedy an abnormally fast heartbeat (230 beats per minute or greater, IIRC) or ventricular fibrillation (uncoordinated contraction of the heart muscle that can quickly be fatal as the heart does no useful work.) Fortunately, I have never received a shock from my device. I am told that it feels like having a fastball pitched into one's chest! My pacemaker was installed because of a condition called left bundle branch block, brought on by congestive heart failure (essentially an enlarged heart) that was exacerbated by chemotherapy for my Hodgkin's lymphoma. My heart beats fine, but the signal doesn't make it efficiently down the middle (septum) to the left side of the heart. The cardiologist inserted an extra wire through one of the coronary veins to the left side of my heart, so a signal can be sent simultaneously to the right and left sides of the heart, a process known as Cardiac Resynchronization Therapy (CRT). It provides an improvement in pumping action of the heart, when used in conjunction with standard heart medications (digoxin, ACE inhibitors and beta blockers.) Pacemaker batteries generally last 5-7 years, after which the device must be surgically replaced. Rechargeable batteries have not been released for general use due to liability issues (e.g., a patient who needs a pacemaker to live forgets to charge the device and later dies.) Replacing the device also ensures that the patient has the latest technology device (and of course makes a bundle for the pacemaker company!) Battery life nowadays is improved by special programming in the computer (Medtronic calls theirs \"AdaptivCRT.\") The technology only sends out pacing signals when they are needed. My device has a wireless device built in so they can grab all sorts of data from it and/or change the programming when I go in every 6 months for a check-up. Also, I have a bedside monitor that collects data from the device every few months or if a major event occurs, then it sends the data to the manufacturer over the cell network.",
"In the most basic of terms your pacemaker is constantly taking an EKG from inside your heart from the leads placed into any combination of the right atrium, right ventricle, and coronary sinus (left ventricle) and it senses from that “EKG” when it needs to intervene. It only takes a tiny amount of electricity to mimic the hearts own electricity so the battery can last anywhere from 6-12 years.",
"For a time, they made and implanted nuclear powered pacemakers, because \"Hey, what could go wrong??\" There were a couple different variants, including a plutomium powered one. All the details and a good overview of how pacemakers work too: [ URL_1 ]( URL_0 )"
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croazk | Why do renewable energy sources store excess energy in batteries instead of converting water into hydrogen and storing it | Technology | explainlikeimfive | {
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"Efficiency At 100% efficiency, you'd need 40 kWh/kg of hydrogen produced but in practice it takes us 50 kWh/kg so that's only 80% efficiency. Then you have to run it through a fuel cell to get electricity back out of it and fuel cells are only getting up to about 60% efficient. That gives you a system efficiency of 48% which isn't good. A lithium ion battery is 99% efficient, that means if you spend 100W putting energy into it you can get about 99W back out later. There are inefficiencies in the charger and inverter but they're both in the 90% efficiency range. If we assume 90% for the charger and the inverter and 99% for the battery that gives you a system efficiency of 80%. For real numbers here, if you have an extra Megawatt-hour to store and you store it in hydrogen then you only get 480 kWh back when you're done. If you store it in a battery you get 800 kWh back when you're done. The battery only wastes 40% as much power as the fuel cell",
"For one thing batteries are way simpler. You just generate electricity by the renewable source and feed it in. It is available for use whenever. But generating hydrogen is much more difficult. You need to take the electricity and run it into electrical connections fed into a tank of water. This tank needs to separate the two gasses produced (otherwise there is risk of an explosion), releasing the pure oxygen (fire hazard) and somehow compressing the hydrogen for storage. So you need a water supply for this as well, plus a leak can mean electrocution for anyone unlucky enough to stumble into the puddle. You also need high pressure hydrogen storage (and compressing can get hot). Then to get energy out you need a hydrogen engine that generates electricity, meaning either you are boiling water for a steam turbine or using some sort of fuel cell with a catalyst. Now consider all the stuff that needs maintenance. Your tank, your anode and cathode which are eroding, your compressor, your high pressure gas system, your hydrogen generator (whatever it is), etc. Plus you need plumbing to the site as well!",
"Because the efficiency it lower. According to [ URL_1 ]( URL_1 ) the efficency today is 30-40% compared to over 90% for newer litium ion stogare system. It looks like hydrogen might have the advantage because the energy storage capacity dependent on the tank size so for large capacity storage when for example underground caves can be used it can be useful. For small home use the higher efficiency and and smaller size of batteries is a advantage. For large storage system if you have access to a lot of water and difference in elevation [Pumped-storage\\_hydroelectricity]( URL_0 ) is 70% to 85% efficient. The idea is to pump water up to a reservoir at higher elevation so store energy and let it down as in a hydroelectric power plant when you need energy. The size of the reservoir is independent of the amount of power you can deliver so you can store huge amount of water at relatively low cost. As long as you have a hill to build the reservoir at, water to pump up and not to high amount of evaporation is it the better way to store power with water. For batteries the max power you can deliver depend on the number batteries and therefore the capacity. For hydrogen the amount of power it can make hydrogen and convert it back to electricity is independent of the storage size. So lets say the system has to provide 20 000W for a system that can deliver it for 10 hours battery might be cheaper but if it need to deliver it for 10 days the hydrogen system might be cheaper. The hydrogen system is still less efficient but that is not always the most important part",
"There are chemical issues with producing and storing hydrogen like that. You can't just force more energy into an electrolysis machine and make it work faster. So any given electrolysis machine will have a finite capacity which is largely size dependent. Relatedly you can't shrink it too much because mixing the output hydrogen and oxygen is an explosion risk so those need to be kept apart. Second, any gas storage system will need to either liquefy or compress the gas as atmosphere-pressured hydrogen doesn't hold enough energy to just keep around. This process also takes a lot of energy to operate the machines that do the compressing which will bite into your efficiencies. I'm assuming you're talking about the scales of a house with solar panels on the roof. You don't want to hear the air compressor running intermittently throughout the day to fill the high pressure gas cylinder that stores your excess power. Batteries are way smaller, easier to handle and don't make noise."
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croiuf | Why do consoles lock at 60fps and don't go higher? | Technology | explainlikeimfive | {
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"A lot of them lock at 30 FPS actually; 60 FPS is generally a \"new\" trend for consoles. It's because consoles have standard system components and games are designed to run on consoles at standard settings without any room for deviation. So 30 FPS was the trade-off point for ensuring someone could get a good looking game that was still going to play smoothly.",
"Consoles are limited to 60fps because that's the frequency most televisions accept. Old school CRT televisions operated at 30 fps, but that signal was interlaced which means half of each frame was drawn at a rate of 60hz. When progressive scan HDTV was introduced they simply stuck with a 60hz signal, but drawing the whole frame at once effectively doubling the framerate to 60fps. Most PC's are limited in the same fashion. The actual FPS output will always match the refresh rate of the monitor. If a PC game runs at 100fps but the monitor can only do 60fps, only 60 percent of the frames end up on the screen."
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crrkel | What exactly were people afraid was going to happen during Y2K? | Technology | explainlikeimfive | {
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"It used to be common practice for developers to only assign 2-digits to represent a year, so 1988 would be stored 88. This was done to save memory, because memory used to be very expensive and saving a couple of digits here and there would make a big difference. The problem is the 19' part of the date was assumed, so when the year 2000 rolled up computers might think that the date was Jan 1, 1900. For example this could cause things like banking software to malfunction and process payrolls, interest, and loans incorrectly and could throw much of the financial industry into chaos. Ultimately the media blew the issue out way of proportion. Sensationalizing what could go wrong and effectively preaching doomsday prophesies. While it was in fact a big problem, developers had been aware of this problem for well over a decade and in a lot of cases had already fixed it. Where the problem lay was in older systems that companies had refused to update or replace. While some companies did have to spend a lot of money and resources to solve the problem, In some ways Y2K became little more than a marketing ploy to force companies to replace obsolete equipment. When the day came, there were a few issues here and there but generally speaking Jan 1, 2000 nothing bad happened. My old boss was working for an insurance company at the time and she got to spend New Years Eve on 2000 sitting in the server room with her staff with a bunch of take-out Chinese Food just in case something broke... it didn't. The IT staff and developers had complete confidence in the changes, but management fueled by the media didn't. My favorite story of Y2K was at midnight of Jan 1, 2000 I was watching TV and the Space Channel in Canada started a fake news broadcast claiming the world was ending, power was shutting down, the stock market was crashing, etc. They even had a guy walking in the background on fire. Obviously it was a joke, and it was pretty damn funny. The ended it with the text \"In the spirit of HJ Wells War of the Worlds\" a nod to when a broadcast of a reading of the novel on the radio caused a panic when people thought an alien invasion was happening for real...",
"In computer systems, the year was stored as a two digit number. 1999 would have been witten as 99 and the computer would interpret it as 1999. This was common practice for computer systems in the 20th century and was done in an effort to use less space on the system. With the start of the year 2000 (y2k) people were afraid that the computer would interpret the year as 1900. This bug would have become a problem in anything which relied on dates to function. Banks used the date in order to calculate intrest. For intests calculated daily, if the date went from 1999 to 1900, instead of calculating intrest for one day, it would calculate intrest for -100 years. Power plants had computers routinely do checks on the various equipment. Without the correct dates, they'd have no way to accurately know if something malfunctioned due to the systems checks not being able to accurately compute everything. Airlines relied on computes to track scheduled flights and with the date going back 100 years, it'd screw up the entire system. A lot of equipment relied on dates in order to function. Without the correct dates it could lead to a system failure and incorrect results from computations. Luckily, a lot of this was fixed before 1/1/2000 and this did not become a big problem. With that said, there were still systems not updated before 1/1/2000 that malfunctioned.",
"God the misinformation in the posts is amazing. I actually managed a machine that failed on January 1 2000. We completely missed it in the shakedown leading up to the calendar event. Fortunately it was a rather low impact, as that machine managed the rotation of yearly backup tapes, it recalled the tapes which were expired (more than one year old), and ready to be reused, as our backup strategy was such that we could restore anything up to one year. The real kicker, was that the machine (UNIX) was working fine, the software that recalled the tapes was wrong. I was heavy into scripting in PERL at the time, and was able to read the plain text database, and get the job done by re-scripting the job. What happened was to save memory, as many said below, the year was written as 19 < joined with > 88 = 1988. So when we got to 19 < joined with > 100 the result was **19100**. So on January 1st, the year of our lord 19100 all of the tapes written in 1999 were quite a bit more than one year old ... hell, they were 17,100 years old !!! So we recalled them all."
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crue9h | How can nuclear launches be detected and identified? | If Russia launches at The US, how does the US know that it was Russia? | Technology | explainlikeimfive | {
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"Between satellites and radar, it is pretty easy to track anything that flies like a rocket. Rocket exhaust is really hot, and infrared cameras in space can spot them launching. Once it is airborne, an ICBM flies up to the edge of space and then flies unpowered over to its target. During this phase, it is a large metal object sitting in the middle of a big empty area, and radar has no trouble spotting it. From here, we can extrapolate its target based on its current path, since its engine has turned off. It is difficult to figure out if the payload is nuclear or not, but usually if an ICBM is launched at anything other than a military base, it is probably going to be nuclear.",
"[Here is a rocket launch, seen from the International Space Station]( URL_0 ). You can see it with the naked eye (or a regular camera, in this case) over something like 1000 kilometers. Sure, it was the night side of Earth, but you can imagine how easy it is for a network of specialized satellites to pick up such a launch. Radar works very well, too.",
"There's a few arrays of satellites in orbit watching for bright or hot spots on the ground. A rocket launch is this intensely bright and hot spot for about a minute, far far brighter than anything around which makes it easy to spot. All rocket launches and missile tests are publicized in advance because they'll trip this warning system These same satellites can also detect a nuclear detonation on the surface. They work in conjunction with the seismographs around the world which are used to detect earthquakes but were initially installed to detect underground nuclear tests."
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crvd47 | How can the power go out during a storm and then come back the next second? | Technology | explainlikeimfive | {
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"Lightning hits an overhead wire, and trips a breaker. The breakers are auto reset on the first trip, so the lights come back on after a second. If the fault is gone, like lightning, the power stays on. If the fault remains, like a tree on the wires, then the power stays off.",
"When there's a fault somewhere on the electric grid (such as a power line shorting out or going down), quite often automatic systems will flip circuit breakers that shut off power to other parts of the grid. This can prevent a single point of failure causing a cascading set of faults that brings down the entire grid. Once computer systems have a few moments to analyze the situation, power will be restored to parts of the grid that are safe, while isolating any areas that need serious repair. This whole scheme can be a little complicated, since one part of the grid having a problem can cause brief surges on other nearby parts, making it seem like they have problems too. So sometimes the power can actually go down and up a few times before everything stabilizes."
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crycu1 | If transistors in computers act to switch off or on the flow of electricity, what mechanism acts to "decide" whether it should be switched? | Technology | explainlikeimfive | {
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"Other transistors. Yes, this sounds circular, and it sort of is. At the very \"start\" of the system (I.e. startup) there are some circuits which are not controlled by transistors and are hard coded to do specific startup actions; but from there it's all controlled by some transistors signalling others to switch, which signal others etc. and coming back round to the original ones at some point.",
"If you tie a bunch of transistors together, and have them all control each other, you've basically made a microcontroller or a computer processor. Inputs into the machine (key pressed, network traffic, whatever) are the thing controlling the transistors, which end up modifying other transistors. With clever arrangement those transistors that are activated and those that are not end up being cleverly made to do something useful, which results in some transistors being activated which then control outputs (e.g. the screen, a printer, a speaker, whatever). It's like a giant puzzle, with billions of transistors arranged in very clever ways to make simple inputs get acted upon to produce simple outputs. Every game you play, program you run, etc. is just the result of those clever arrangements of transistors switching their output on or off based on their \"control\" deciding pin. If you think \"How can that work, if you tell it to switch on, it switches on, otherwise it's off\" then you're right. But with arrangement of the circuit and the voltages on it, you can very simply make a transistor do to opposite (e.g. when you tell it to switch on, it \"shorts\" the output so it actually outputs the opposite of the input). That's a NOT gate, in logic-gate terminology. The transistor itself is an AND gate... when input and control are both turned on, the output is on, but otherwise it's off. And with a bit of simple wiring of ANDs and NOTs (or just transistors themselves in a certain pattern), you can make an OR gate (where output turns on if \\*either\\* of two inputs is on). Once you have the equivalent of AND, OR and NOT (actually you only really need two), you can make every other type of logic gate (e.g. XOR). And when you have all the logic gates, clever arrangement of them can form a Turing-complete machine, like your computer. And even the base, core language of the machine (machine code, represented to us as assembly language) literally includes AND, OR, NOT and XOR as instructions on the processor itself. So once you are there, every single machine code instruction is just a certain arrangement of logic gates/transistors to do what you ask (e.g. ADD, MUL, etc.). A transistor is just a single building block. Put together with wiring in certain ways, you can make more complex blocks. Put together in certain ways, those blocks can form logic gates. Put together in certain ways, those gates form everything you need to make a processor. You need billions of them. They all need to be arranged in a particular fashion. But basically a simple \"switch\" can make all the computers you see today. It's like a giant mechanical machine made of nothing but ball-bearings (electricity) and seesaws of wood (the transistors). Pop the ball bearing into the top, let it clack down and hit the seesaws on the way, and get redirected, etc. If you arrange the obstacles cleverly enough, it can do calculations. Basically the concept behind the Turing Tumble teaching game which some schools use to teach computing."
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crydeh | Why haven't we adopted Electric Cars yet now that we know that they are more Eco Friendly and overall less costly than the regular ones? | Technology | explainlikeimfive | {
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"Not everyone can afford to just buy a new car. They only just became affordable a few years and even then most people can't afford a new one. It took a long time just for the technology to become reasonable for consumer use, now the market needs to become reasonable for consumer spending",
"People don't like change and having to wait more than 10min for refueling, even though you probably only need to wait on long trips, because you can charge an EV at home over night, in inconvenient. Furthermore the production of EVs is not completely eco friendly aswell, around 50% of the CO2 produced by a single gas car is during production, the total amount stays the same for an EV. Lithium takes a lot of energy from rock to battery. And the electricity also has to come from somewhere, many power plants use coal, which releases CO2 in the process, some use nuclear power which produces radioactive waste, wind parks destroy environments, etc. Doubters will say it does not make a difference to use EVs. And EVs are currently more expensive to buy, and even though they are way cheaper to maintain, people don't like things that seem expensive on the surface. They like things that seem cheap but rip them off without them knowing.",
"The main issues are charging station in range for longer trips and that the batteries have to be replaced every so often at quite a high cost. Although I have solar at my house to help with the normal charging part, I tend to drive a car till it is 11-13 years old, so I would not be looking forward to that huge bill versus a Honda or Toyota gas engine that runs till 200K miles.",
"Ramping up to full production, to supply all the earth's requirements for cars, takes some time. There just isn't the battery production to do it at this time. But we are working on it. But the Earth is also working against the entire current automotive industry. One that is fully set up to produce gasoline cars, one that has lots of money wrapped up in producing gasoline engines, but woefully under-prepared to make electric ones. The longer they can keep the world from going electric, the better for them. They are being dragged into the 21st century by startups that have shown the world that electric can do it, that an electric car is so much better than a gas one - but they are still doing there level best to portray gas cars as high tech excitment, and battery cars as boring, utilitarian buzzboxes. And with the sticker price of gas cars remaining well below that of electric cars, it's an easy sell. But battery prices are falling with bulk production, the gas engine's time is limited. The gas cars sold today will be scrapped, not when they are worn out, but because they burn gas."
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cs1g8i | why did WinRar become a thing if all Windows versions could read and make ZIP files? | Technology | explainlikeimfive | {
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"WinRAR has existed since 1995. Windows didn't get ZIP compatibility (known as \"compressed folders\" back then) until Windows XP, which was released towards the end of 2001. And even then it might have been something exclusive to XP Professional, not every version of Windows.",
"WinRAR did have some features like easy splitting of an archive into multiple files, common for people who couldn't download a single huge file or the risk of failure was high requiring a full restart. The compression ratio was better than regular ZIP. These are significant features for people who may be on dial-up internet. Its main competition on old versions of windows was WinZIP, appropriately enough. All in all, WinRAR was a competitive product back in the day."
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cs2iww | How does this power board connect to the wire? | There is this new project on Kickstarter, its an extension cable, but you are able to slide the power board anywhere along the length. How does the board access power through the insulation? URL_0 | Technology | explainlikeimfive | {
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"Well, I can think of a few ways it could be done. I don't know that anybody here will be able to tell you how that guy did it. I will also mention that kickstarter is riddled with awesome ideas for things that *could* be done, but are actually just scams. One thing I can think of is that, since the cord seems to be made of fibers, a needle could be driven through the fibers and into the wires. This seems unsafe, but it is all I can think of for the thing shown in the video. A way that I could imagine it being done involves a separable extension cord where the live and ground terminals are zippered together, and they are separated and turned around wheels which allow them to form a transformer with a coil inside of the board, and thereby transfer power. Unfortunately, this wouldn't work with the wire setup this guy uses. So really, I don't know, and am suspicious of it as a potential scam.",
"There is nothing in the marketing indicating how it works or even that it even works at all. Notice how there is never a single clip showing the device being moved along the cord and it supplying power but rather the camera cuts between those actions. This indicates that they have two prototypes, one that they can slide along the cord and one which can supply power. All the marketing is about the design and how great it would be rather then anything explaining how it works or if it is safe. They do mention UL and CSA but does not provide a certification number or even claim they are certified, something any electronic device is required to. This is a common problem with projects on kickstarter. Most new products gets funded through large single vendors who have more training seeing how far in the development cycle things are and how much it would take to finish it, if at all possible. However in order to fake the operation of a project on kickstarter you only need a finished design without any working internals. Clever editing or hidden components can fool people into thinking you have a finished product that only needs a bit of fund to kickstart production.",
"Great question. Electrical engineer here: I have no idea. Let me ask my friends to see if they have any idea"
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cs4cxo | Do Map apps add stop signs and red lights into travel time? If so how? | Technology | explainlikeimfive | {
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"For each segment, the road between two places you could turn, there is an \"average travel time\". This ATT parameter includes the time spent at a stop sign and the average time spent at a traffic signal (it's plus 0 if the light is green and x if you have to slow down, wait, and go again). When their is traffic, a \"traffic penalty time\" is added to ATT. Minimization of ATT is the benefit function used to select a route.",
"I'm pretty sure Google Maps uses location and speed data from people's cell phones who are out and about to judge travel times, traffic, etc.",
"No, but they do add the wait time. So it may not know that a stop sign or red light is there, but it knows that there is a delay at that particular spot. They do this by learning the time it takes for a user to cross from one street segment to the next street segment. And it can learn that on Mondays, at this particular 15 minute time period normal wait time at this intersection is 1 minute 29 seconds to cross from this street segment to the next street segment."
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cs4e1z | Why is 720 pixel resolution the same across a phone, laptop, and tv? Shouldn’t the image become less clear as the format grows larger? | Technology | explainlikeimfive | {
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"It does. But there's a bit more at play. Larger screens are typically viewed from further away and the distance makes it harder to tell. Being further away makes the pixels take up less of your field of view, which has the same effect as reducing the pixel size. The closer you're viewing distance, the higher resolution you need for the screen to look good. My phone has the highest resolution and my TV the lowest. Edit: you also get to the point with a combination of distance and pixel size where you're eye is physically incapable of seeing the individual pixels"
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cs4eqx | In a pre-OS computer era, how did someone create a OS? | I mean, it seems pretty stupid, but I can't warp my head around this. | Technology | explainlikeimfive | {
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"Well an OS is software, human readable code compiled by a program into numeric instructions that can be executed by a computer. But nothing stops a smart and determined human from reading the hardware documentation, which lists both the instructions and their numeric codes. So if you want to write an OS without a computer you just need some reference manuals, some paper to write the instructions on, and then some more reference manuals to translate each instruction you make into a set of numbers that can be understood by the computer. Computer hardware is normally designed with some way to read an initial set of these instructions into memory and begin executing them. Before harddrives and floppy disks a lot of data was stored on punch cards or punch tape - this was physical media which you could \"write\" to with a simple hole punch. For example look at this [this]( URL_1 ). It's a very old punch tape signed by Bill Gates and Paul Allen, the founders of Microsoft, and it represents the \"OS\" for the first successful home computer called the Altair 8800. [This]( URL_0 ) is a more robust copy of that tape which allows you to see some of the code. See the line of small holes? That's the guide with each hole being the alignment for one byte as it is fed through a machine. See the larger holes and notice how there is space for 3 below and 5 above, for a total of 8? Those are the 8 bits that make up each byte, and those bytes represent computer code. Using a hand punch and enough time you can physically create one of these without a computer. Of course both of these were punched by a computer but it's known that Paul Allen, flying out to demonstrate it for the first time (and in fact the first time it would be run on the actual hardware) realized he didn't have a bootloader with him, the program used to load the rest of the OS into memory. So with a pencil and his mind he created that very tiny program and then hand punched it in time for the meeting.",
"The first commercial computers were all mainframes, and they didn't have operating systems. Each user would have sole control over the entire machine for some timeframe. Their programs were entered into the machine typically through punch cards, which were mass produced, printed, cut cards that you could either use a hole punch, or a typewriter type machine to punch holes into the paper. The paper had a printed grid to help the user understand the significance of what they punch and where, and there were notches for the machine to understand the orientation and facilitate reading the card. The user would enter his program this way, and the cards were ordered by hand. The cards would enter the machine like you see in a card shuffler, with a weight placed on top. There were also punch tapes, typically used to store computer generated data, because to punch a spool by hand doesn't sound like fun, and there were control panels with button, lights, and switches. Each program had to be written for THAT machine. If you wanted to read data from tape, you had to program into your punch cards how to read from tape, a hardware driver, in modern parlance. As machines got more sophisticated, assemblers and compilers came along. This gave birth to the first programming languages. The compiler was punched by hand, loaded into the machine, and then the program in your programming language was encoded into the cards, which was input to the compiler program you just loaded. This is where that typewriter device really came in handy, because it would type the characters in ink across the top, and punch the holes that represented the character in the card below. Programming got more sophisticated. Instead of programming straight binary in terms of punch holes, they were now *symbolically* processing with programs. Machines, too, evolved. By the later 60s, magnetic storage was getting increasingly common. Now instead of writing the instructions to read off punch tape right into my program, I could instead write instructions to call routines that already knew how to read from tape. Someone wrote that for me already. It was specific to that device as it was connected to this machine, and that means my program could call \"read tape\", and if ran on any similarly capable machine, it would \"Just Work(tm)\". This is the birth of the operating system. Programs that did common tasks for the operators, and tasks specific to that machine. Why rewrite a routine into my program that does a thing that I'm going to do in ALL my programs? And things got more sophisticated from there, as machines got more sophisticated, now you have multiple operators running their programs, and that needs to be managed, and audited, and rules have to be enforced so work is done fairly and under priority. Tasks got more automated because it was a better use of the operators time and more efficient use of the machine. Remember, we're still in the late 60s to the early 70s. No internet, no super computers. We're seeing the first keyboard terminals with paper drum output, not even video consoles yet. Enter Brian Kernighan and Dennis Ritchie aka K & R. By their time, there are already concepts of \"operating systems\" floating around. They're tasked with giving a crack at it, at IBM. At some point, someone used punch cards to enter machine instructions to make a programming language compiler. They used a programming language and encoded it into cards like I described above to make a NEW programming language, called C. Why C? Because there was already an A and B programming language. They invented C so they could write the Unix programming language. History was made. Unix and its knock offs and its descendents constitute the most successful line of operating systems in history. Apple OSX and iOS are Unixes, Linux is a Unix. Android phones are all Unix. Windows is another story, not a Unix. For the most part if it's a computer and it's got an operating system on it and it's not a Windows product it's almost certainly running Unix. Late 70s to early 80s, IBM and Sun and Xerox are suing each other over what's a Unix, the whole industry is squabbling over patents. Xerox founds Palo Alto research and basically invents the future. The executives demonstrated what executives don't - they don't understand what the fuck they have or what they're doing. They thought Palo Alto was a waste of money and everything they did was stupid. So here comes Steve Jobs and Bill Gates. They had unfettered access to everything in Palo Alto, none of which was copyrighted or anything. Because who cares? Palo Alto mostly just played with software, which are just bits! It's the hardware that's important... So Bill and Steve go off and found their own companies focused on software. Steve uses an IBM processor in his computers. Bill starts a software company and doesn't even bother to write his own OS, he BOUGHT PC/M off some crackpot who invented it. They renamed it MS-DOS. I don't even think Bill and his team wrote Windows, they may have bought that, too. Another side story is that of Intel. They were an upshot little company that made parts for radios and power supplies, and decided to get into logic gates and control logic. They developed their 4004, their 8008, then the 8086. And that became a popular (CHEAP) platform to build computers that ran some variation of DOS. Then spawned the 80186, 286, 386, 486... All desktop processors today are made by either Intel or AMD, and they're all direct descendants or clones of the 86 instruction set. Intel tried to make a 64 bit version of their processor which was a total market flop. AMD made the x86_64 version we all run today, and Intel cloned AMD, which is a clone of Intel, meaning Intel cloned themselves! Oh boy. Anyway, while all the big guns were fighting over Unix, which was a rather sophisticated piece of software, you have these stone-age upstarts who have to discover fire for themselves. DOS was primitive, as far as an OS was concerned. It booted into a text prompt you could type commands, and gave you some bare facilities enough to read from floppies and hard drives, look at file systems, and launch programs. And this is late 70s to early 80s, so we had electronic keyboards and video terminals by now. But Bill Gates started his programming on an Altair 800, with toggle switches on the front. Steve Wozniak accidentally discovered how he could drive a video encoder to show 4 different colors. Life was primitive. When a program launched, there wasn't enough memory for both the OS and the program, so the OS was unloaded entirely, and the program took over. Old 80s DOS games had to have all their own hardware support, drivers, built in. I can't comment on Apple machines, because while they were far, far more polished, A) they weren't Unix back then, either, and B) no one but schools bought them. There was the likes of the Vic Sinclare and the Commodore 64, but they had a BIOS, a read-only piece of memory with software on it that sort of served as an operating system. At least it was always there and accessible by your programs. It wasn't until Windows 95 that the desktop market really took hold. This was a full featured operating system that had software support for multi-tasking, where programs were rotated through, each got to run on the CPU for a time slice, so it looked like all your programs were running at once when they weren't. But the big thing was the OS provided a layer of abstraction - your programs didn't have to support hardware, they just called \"write()\", and the OS knew what to do and how to do it. This made programs much simpler. Unix had always had this, but again, squabbling, lost market opportunity because executives are stupid, and they were totally blind to this new market opportunity. They basically let Steve and Bill have it all, and now those formerly big companies aren't really all that important anymore. Oh, and Steve was voted out of Apple's executive committee in the middle 90s, and he was so pissed he sold off all his Apple stock and founded Next Computers. There he picked up a Unix operating system. Then when Apple was doing SO bad, they literally begged him back, and he brought Next with him. All modern Apple computers share most of their lineage with Next computers and their OS, which was a clone of BSD Unix. And then IBM worked with Sony in secret to make the Cell processor for the PS2, and didn't include Steve in on it - their biggest and just about only customer, and Steve was so pissed, he moved their entire platform to Intel out of spite. That was the last vestige of the old MacIntosh computers finally cut out. Oh boy, that's quite a history lesson, and really I don't know how else to tell it in a clear way, there are so many influences on why operating systems are a thing and where they came from and how they got here. This is all just one answer to your question. There are other timelines and details that are also going to be correct. Feel free to ask and we'll see if we can't be a bit more concise about any specifics you're interested in."
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cs4vi8 | How do things like computer processors and all those black chips on circuit boards work exactly? What's inside them that does all the magic? | Technology | explainlikeimfive | {
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"All those integrated circuits are full of transistors. These are little semi-conductor parts that use a fixed set of rules to calculate their outputs from their inputs. One of the signal wires running into those parts is called the \"clock\", and they can perform complex operations by doing them in many small steps, one step per clock cycle.",
"They're made of a ton of logic gates that electrons flow through. You can imagine it like a complex system of pulleys, and the way they're put together can perform a certain task"
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8,
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cs5ffu | who owns the internet? | Technology | explainlikeimfive | {
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"text": [
"Nobody. The internet isn't a single thing, it's the collection of all computers connected together. The wires themselves that connect those computers together are owned by various companies, some private, some public.",
"The wires connecting the different computers are owned by a whole host of different companies. There's no one owner of \"the internet\" (that wouldn't be possible, since \"the internet\" isn't a physical object)"
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cs5qof | How does your phone turn overheard words or phrases into targeted ads? | Technology | explainlikeimfive | {
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"excuibn",
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"text": [
"The targeted ads are chosen based on a bunch of data they collect on you. While this is kind of creepy, it does mean that you get a tailored experience. As far as the spoken data, most of the cookies (or bits of information about you) are collected through google or one of its partners. Google devices, or things that are listening for you to say, “hey google” typically have that feature on because they’re listening for your commands anyway and might as well. For most other people it is generally automatically off. There is also a google settings page where you can tell it to not listen or pay attention to certain things you do. Hope that helps!",
"It doesn’t. You just google stuff a lot and forget about it mostly and then get ads for the things you Googled."
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cs5s13 | How do multifocal CONTACT lenses work? | I understand how normal progressive lenses work, where you basically look through particular part of lens, but with contact lens anywhere you look you look through it the same way, aren’t you? | Technology | explainlikeimfive | {
"a_id": [
"excq86w"
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"text": [
"The lens forms two images, one focused on near and one focused on far. Both images fall on the retina, and the brain interprets the brightest one. If you look at a small distant light, and then take your glasses off, you see a large blurred smear. This is the same number of photons spread out over more sense cells in your eye. The eye's sense cells respond more strongly to the sharp, bright light from the correctly focused image than the blurred, dim light from the incorrectly focused image. There are anomalies, like a star might have a blurred ring around it because at night there isn't any bright focused image falling on those sense cells next to the ones that are seeing the star. But, your mind can get used to it."
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8
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cs7bkr | How does ultrasound work? | What is the basic physics of ultrasound? How are the images produced and processed from just a probe? | Technology | explainlikeimfive | {
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"exdd6dx"
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"text": [
"Ultrasound, like any other sound, is a wave, and all waves show certain properties. For example, waves can bounce of different materials. The ultrasound probe contains what is basically a speaker and a microphone. The speaker generates ultrasound, which is sound with a frequency higher than what our ears can perceive. It's important that the sound is of a high frequency because, simply put, that sound tends to not \"spread out\" as much as low frequency light. (This is called diffraction, if you wanna look it up). This is also the reason you have to aim your speakers, but you can place your subwoofer pretty much anywhere. When the speaker inside the probe generates the ultrasound it passes into the body. The speed of sound is constant inside any given material, but it differs from material to material. The speed of sound in air is about 340 m/s, whilst it is approximately 1500 m/s in water and 5000 m/s in iron. This difference is because of lots of different kinds of physics, and we don't have to go into that now. Now, when the sound wave move from one material and into another, some of it (but not all!) is going to be reflected back. How much sound is reflected depends solely on the difference of the speed of sound in the two materials. This is the same thing that happens when you look at your reflection in a window pane. Sure, you can see what's on the other side, but you can also see your reflection. Here comes the clever part: When the sound waves are reflected, the microphone inside the probe notes down at what time the sound was detected and how loud it was. It's basically the same as an echo. Since we have many different layers in the body in which sounds moves at different speeds, the microphone is going to hear lots of different echoes at different volumes. Using some math, a computer can then calculate how much sound was reflected and how far into the body, and we can sort of \"feel\" the inside of the body using the ultrasound. Lastly - there isn't only one microphone inside the probe, but several. By measuring the difference in time it took for the sound to reach the different speakers, the computer can then calculate where the sound came from by triangulation. This is also the reason you have two ears instead of one. When you hear something, there is a tiny difference in when the sound reaches your eardrums, and your brain uses this tiny difference to calculate where the sound came from. Try to cover one ear and close your eyes. Determining where a sound comes from is going to become much harder!"
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cs7nw2 | Why do WiFi signals fluctuate in a house when objects remain static? | Technology | explainlikeimfive | {
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"text": [
"I'm not very certain about that, so maybe wait until someone else can ELI5 that. But one reason might be that signals from other sources on the same frequency might be interfering."
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cs8m15 | What exactly is a ‘mod’ in video gaming? | I’m a big gamer but have only ever played console games, never PC. I’ve always known of the existence of mods whilst never knowing what they really are. Can anybody mod a game? Is it legal? Why do developers allow games to be modded? What does it allow players to do? Thanks! | Technology | explainlikeimfive | {
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"So basically a mod, short for modification, allows you to alter something in the game. For example, in Starbound, the developers opened the game up the the modding community. People developed mods to add things like wine and beer making into the game, added new armor sets and weapons, new minerals to mine for etc. Anyone can make a mod if they have the technical and creative skills. There are a lot of mods that break the game either literally by making it unable to start or figuratively by breaking mechanics that made the game challenging and enjoyable. Also, certain games, typically triple A titles like Halo or Destiny don't allow much in the way of mods, typically its smaller indie games. The reason small development teams allow this is because it increases the playability of the game and in many cases extends the end game for hundreds if not thousands of hours. The small indie dev teams get all this for free as the modding community is mostly just fans working on things for fun in their own time.",
"> Can anybody mod a game? Yes. It might require some skill. How much skill depends on what tools exist for that specific game. > Is it legal? Usually, making and giving away mods is legal. A lot of PC game companies actively encourage it. Many games are deliberately designed to be easy for community members to add new art, levels, characters, game rules, etc. Of course, giving away (or selling) copies of the game itself (or big parts, like the art) is illegal. Unless you somehow got permission of the person / company who owns the rights to the game. What if you want to sell your mod (but people also have to buy the game it's based on)? Check the fine print in your game's license (EULA). It's often forbidden there. I'm not sure if this EULA term is legally enforceable, but be prepared for a game company to sue you if you make a mod and try to sell it. As long as you don't try to make money off it, for the most part developers either don't care, or actively encourage it. > Why do developers allow games to be modded? Imagine you run a game company. That means you pay -- sometimes big bucks -- to professional artists and software developers to create all the parts of a game and its content. Then someone tells you that random Internet people, for free in their spare time, will improve your game or create additional content. Any smart business guy will love with that idea -- getting somebody to do, for free, something you'd normally have to pay people for. > What does it allow players to do? PC's aren't \"locked down\" the same way consoles are. So with a PC game, literally all of a game's programs and data files can easily be manipulated by anyone who has the game. A game can be modified to do literally anything the PC can do. Of course, you have to figure out how the programs and data files work. It's very tedious, technical work. This kind of \"reverse engineering\" is usually how older games are modded (figure games released before 2000 or so). About the time the Internet really started to get wide adoption, game companies started to include tools and ways to change specific aspects of the game. You often no longer need to reverse engineer the game to create your own content. You can go to the game's official website to get documentation of how the scripting system works, written by the game developers themselves. Or there are options like \"Level editor,\" \"Mods menu\", or \"Steam Workshop\" conveniently located in the game, menu, or launcher. The graphics, music, and sound effects might just be right there in a folder or a zip file. Edit them in-place, re-run the game, suddenly you've changed how things look or sound."
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cs94sl | How does an e-mail service decide if an email is spam or something important? | Technology | explainlikeimfive | {
"a_id": [
"exdbzi9"
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"text": [
"SPF records with DKIM, DMARC, condition based spam filters(if sender unknown or when attachment is not allowed), Global Spam repositories. Depends what has been configured mostly. I know this because I failed to answer this question and missed the opportunity of a lifetime. So yeah it hurts and I'll always remember it."
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csbl67 | Why are the ends of passenger jet wings typically curved upwards? Does the size matter? | Technology | explainlikeimfive | {
"a_id": [
"exdtn6a",
"exdttsx"
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"text": [
"The angled ends reduce vortex formation at the ends of wings. Air under the wings is under higher pressure than air over the wings, and so it tries to go around the wingtip from the bottom to the top. The fins at the wingtips block the air's path, making aircraft more efficient and generate less turbulent wakes.",
"They are called winglets or wing devices and help reduce drag thus increasing fuel efficiency. Here is a little diagram with a rudimentary overview of how it works. URL_0"
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"https://www.grc.nasa.gov/WWW/K-12/airplane/Images/winglets.jpg"
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csdj6l | What are the differences between different types of picture formats (jpg, png, gif, etc)? Are some better than others? | Technology | explainlikeimfive | {
"a_id": [
"exe5qld"
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"text": [
"JPEG is a lossy-compression image format. What this means is that when the image is compressed, some of its details are discarded in order to make it take up less space. JPEG is designed to work on more natural pictures, mainly photographs, where close pixels tend to have similar colors, and compression artifacts are less noticeable. GIF uses non-lossy compression. The main \"feature\" of GIF files is the limited palette - instead of supporting the full 2^24 colors, GIF uses only up to 256 different colors at a time. This allows each pixel to take up less space (only 1 byte instead of 3, before compression). GIF is mainly useful for images with a small number of colors, such as charts or icons. GIF is not recommended for photographs. GIF has two additional features: layers, which allow you to have more than 256 colors by layering two or more images with two different palettes (where the top layer has one \"transparent\" color, which lets you see the bottom layer), and animation, which simply lets you store a series of images inside the same file, which are played sequentially. This is mainly intended for use in simple short animation (like a blinking smiley face), not full on videos. The reason animated GIFs are commonly used in place of an actual video format is that until a few years ago, GIF was the only animated format that was supported on every possible platform. PNG is a modern file format, intended to replace GIF. It uses non-lossy compression and supports the full color palette instead of just 256 colors. It also supports transparency (unlike JPEG). PNG images take up more space than JPEG, but they preserve the original image quality since the compression is non lossy."
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csf7qw | How do headphones work? (As in how does electricity get turned into sound) | Technology | explainlikeimfive | {
"a_id": [
"exedn5d"
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"text": [
"Headphones are just speakers writ small, so let's discuss speakers. A speaker, fundamentally, is a cone of some sort of material, attached to something called a \"voice coil.\" The voice coil is essentially just a coil of wire wound around a frame. Electromagnetic theory tells us that driving an electric current through a wire makes a magnetic field that varies with the voltage. There's also a permanent magnet attached to the frame of the speaker; when a magnetic current arises around the voice coil, it vibrates because of magnetic attraction and repulsion. This vibration causes the speaker cone to vibrate, and that causes the air to vibrate, which is what sound is. A pair of headphones is just a really small speaker right next to your ear."
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csffdk | Why can a computer take minutes to run a couple lines of code, yet can run complex things like games so quickly? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Because \"Lines of code\" is not a good metric for how computationally intensive a piece of software is. Consider for instance the following code pieces. repeat(20){ print(\"Hello!\"); } and print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); print(\"hello\"); Both of these programs do the exact same thing and are equally complicated, but one is six times longer than the other. There are a few factors that can cause a \"couple of lines of code\" to have a long computation time. * The lines of code include a very large loop or recursion pattern that means those few lines are repeated so often they would take thousands or millions of lines of code if the loop would be expanded. It doesn't matter how simple something is, if you're doing it hundred million times you're going to take a while. * The lines of code are just abstractions for more complicated behavior that *does* include much more than a couple of lines of code. Say the code snipped I posted above would be defined in a function named \"sayHello();\", now our 3 lines (or 20) are just a single line. * The code is waiting for something to happen, say waiting until a website responds to it. * The code is poorly designed or written and is doing something in an inefficient way when it could be written more optimally. Say instead of more normal method of sorting cards you throw the deck in to the air, and then check if it happens to land sorted on the ground. If it isn't, throw it again in the air. Repeat until the cards are sorted. You could implement that sorting method (named bogosort) in very, very few lines: but because it's just random shuffling and checking if the shuffle happened to be sorted it takes hours to finish for any decently sized list. Video games generally are optimized and don't include massive loops or slow behaviors because they need to be run many times per second and finish quickly enough that the user does not notice. If your code slows down the game it's gutted and a better version achieving the same thing written in. Games are also often do more complicated (as in require more lines) versions of certain tasks in order to make that task able to either finish faster, or be able to stop and start at any point so it can split the execution of the complicated task over multiple frames.",
"What do you mean by \"a couple lines of code\"? Take this code for example: while (true): print(\"hi\") These are just two lines of code, but will run endlessly. So it depends on what the program actually does."
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cshkbn | When Wi-Fi says: "connected, no internet" what's actually happening? | Technology | explainlikeimfive | {
"a_id": [
"exeryk8",
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"text": [
"You are on the local wi-fi network, but that local wi-fi network does not have an internet connection. Think of wi-fi like a bus you can get on, and the internet is the highway. You can get on the bus just fine... but the on-ramp to the highway is closed, so the bus can't access it. You can still see the other passengers (computers) who are on the bus with you, and pass files back and forth or have a local game with them, but none of you can reach the internet.",
"Your wifi is really just a device that both has its own network and connects to a wider network(the internet) . It's own network is called a Local Area Network(LAN) and the wider network is called a Wide Area Network(WAN). The LAN is used to communicate with devices on the same wifi such as sending a document to your printer and only exists on your wifi, the LAN literally is your wifi. The WAN is the internet. So when you get this message you are connected to the LAN and can print stuff but you are not connected to the WAN."
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csizcb | How is possible that games like ES6 and GTA VI are being developed with hundreds or thousands of people but they can still keep it a secret? | Technology | explainlikeimfive | {
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"Employees have to sign non-disclosure agreements before being let near the project. If they leak any information, they breach the contract and face a hefty lawsuit + most likely lose their jobs.",
"Ive heard stories that even voice actors have no idea what they are acting for. In Fallout 4, the rumor is that the guy who voiced Kellogg didnt even know he was doing a Fallout game until after release and heard his voice in game when his kid or friends kid was playing it.",
"Most people working for game studios are really passionate about what they do - you kind of have to be, for the long hours and low pay (compared to what you could earn in other software industries) - and they don't want to harm their product by leaking. There's also the threat of being fired or sued if the studio figures out who the leaker was. Many times, especially secret assets and plans are also individually distinguished, so they would be able to tell who leaked it.",
"“If you tell anyone you’re fired” “maybe the world can wait another month for the actual trailer to release instead me posting an 8 pixel square with 2 colors on it.”",
"As someone in the industry, when working on a project that is in stealth there is really no desire to leak anything. Legally you are under NDA so there is a lawsuit risk, but the real reason is why would you spill confidential information to begin with? You would not gain anything by leaking, you'd just be shitting on your colleagues, especially the ones in the marketing department. Most of the time when an NDA is breached it is a journalist who got their dates wrong and published an article early or an employee updating their portfolio (and in both cases they will know they screwed up within minutes of doing so). And there is a difference between \"keeping a secret\" and \"keeping it confidential\".",
"Non-disclosure agreements work wonders. Essentially this is a pinky promise made between you and the contractor (company) basically saying you cannot speak about this to anybody. If you do, you'll be in heaps of trouble and nobody from the industry will ever look at you. You'll become a disgrace and bring shame upon us all. So nobody speaks about them because they wanna keep making games.",
"A couple of reasons. Compartmentalization is one way. They restrict info on a need to know basis. The biggest way, though is having consequences for being the one who leaks. Not to mention that people who create games absolutely love it and don’t want to be black listed from their career of choice.",
"Bethesda don't even have NDA's! If you leak anything, Todd Howard just comes over, sits in your cubicle with his dreamy puppy dog eyes, and says how incredibly disappointed he is in you. A single tear might roll down his immaculate cheek as he does so.",
"Things leak, but a leak doesn’t necessarily mean it goes on the internet and becomes common knowledge.",
"It's because neither of them is actually in development so there's no actual information to be leaked. :) (Joking, but only partially. My fiancee has given up asking me when the next ES will be released because I kept responding \"No new info yet, sorry.\")",
"They have extraordinary controls on what goes in and out of the network and what goes in and out of the building. They will usually decrypt all outbound communication to look for leaked code, search people on the way out of the buildings, restrict access to USB ports on computers, 'air gap' certain computers, etc etc. It isn't all that easy to sneak information out of those networks and for good reason. That practically indecipherable code is what pays everyone's checks.",
"Confidentiality and non-disclosure clauses. The excitement of being able to share your work prior to the company's wish for that knowledge to be made public is curbed by serious professional and economic consequences if you blab your mouth. edit: compartmentalization too! As someone else ITT mentioned, it's not necessarily clear what the final product will look like or be like if you're just working on a small portion of the finished work",
"Is there any chance GTA VI will be more like IV or San Andrea's than it will be like GTA V? I'm sure people will be mad at me, but I didn't really like GTA V...",
"It's mostly the threat of lawsuits for violating any non-disclosure agreements they had to sign to work on the project. I think most people don't want to have to deal with the legal system and giving up a ton of money just for the sake of posting a screenshot of an unfinished game online.",
"Anyone who doesn't have to know what they're exactly doing or what the project is, they just don't tell them they're working on GTA or anything. They just tell them to make a car animated and make a model for a gun. Sometimes they don't even know they're working for Rockstar, just that they need to do some things to get paid for it. These people are distant from the projects so they're kept in the dark unless absolutely necessary. It's a legal thing where anyone working close with the project has to sign an NDA, or \"Non Disclosure Agreement\" which basically means they promise not to tell anyone or they'll get in trouble. Also if people find out they did this, nobody would want to hire them because they are now a risk for major projects.",
"If they're keeping it a secret how do you know they're developing them?",
"Lots of misinformation in here.. particularly about people working on parts of the game and only seeing that part. This is flat out false, most major studios have processes that output playable builds of the game several times a day for all developers on the project to playtest (at least during production which is almost the entire time). Everyone can see the progress on the game no matter what department they work in. It would be impossible to work efficiently with those limitations with all the interdependencies of the entire process. I’ve only been in the industry a handful of years but it’s been my experience that lots of things do get out, just not to the general public. And nobody ever shares crazy high risk things like release dates or major plot reveals or anything. It’s more like if you have a large network of colleagues across a bunch of studios you might end up hearing some vague info about a work in progress or maybe the setting of a future release or something. It’s just a privilege of being inside the industry, you tend to know more and learn about things before the average person and somehow most people are reasonable and don’t immediately spoil it because most of us are mature adults who respect others hard work."
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cskphf | What exactly is WiFi? Why does accessing the internet on my phone without WiFi cost me data while being on WiFi doesn't? | Technology | explainlikeimfive | {
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"WiFi is just a wireless way to be on a local computer network (aka LAN, local area network). Before WiFi, you had to have a network cable plugged into your device. & #x200B; WiFi isn't technically free, whomever owns the network is paying an internet bill. So if I'm using WiFi at my home, it's using my broadband internet which I pay $70 per month to have. If I go over my data cap, I would be paying more. & #x200B; So what we are dealing with are 2 companies providing 2 products. A wireless connection where you can be anywhere that has coverage (using their towers that they have all over the place), using their internet (and phone) connections, or a wireless connection where you connect to someone's router and use their connection to the internet.",
"Wi-Fi is a wireless radio connection between a device and a local wireless router. Being connected to Wi-Fi doesn't automatically connect you to the internet - the router itself has to be connected to the internet, which requires some sort of internet subscription, usually through some landline connection such as DSL or cable. Places that offer \"free Wi-Fi\" actually mean that they provide a public Wi-Fi that is connected to the internet. Accessing the internet through your phone (without wifi) requires an internet connection through your cellular service provider. Both of these require paying for the internet connection, but a landline connection tends to be cheaper than a cellular connection.",
"Wifi is a wireless way for computers and other devices to communicate with each other. You basically have one computer that broadcasts and receives data, and other computers or devices can connect to it. It's generally used to grant access to the Internet. Normally, when you access the Internet on your phone, your phone connects to a Satellite run by your phone company, who sends you the information you are asking for. They count that as \"Data\" and limit how much you can do. But, you can instead access the Internet by connecting to a local computer that has its own Internet feed, using WiFi. So instead of connecting to a Satellite run by your phone company, you can connect to another computer and use their Internet access instead!"
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cskx6w | How do machines de-shell nuts like sunflower seeds and peanuts in massive quantities without harming the actual nut itself? | Technology | explainlikeimfive | {
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"It varies depending on the type of nut, but generally speaking they go through a machine with a rotating drum inside a stationary drum: the gap between the drums is slightly smaller than the whole nut with its shell but bigger than the nutmeat inside. This gently cracks the shell, and then the nutmeat and shell pieces fall out through the bottom. Typically the shells are separated from the nutmeats using an air blast, which blows the light shells away and leaves the heavy nutmeats behind. How do they do it without harming the nutmeat? Well, they do harm a lot of them, but they use screens and air flow and manual inspection to sort them by size and weight, so the intact nuts get sold in the snack aisle, while the broken ones get sold as chopped nuts, butter, meal, or oil. URL_0 URL_1",
"Peanuts are shelled kinda like grating cheese. There is a set of screens (like holes in cheese grate) in which the whole in-shell peanut is on with holes large enough for peanut meat to fall thru. Then on top is a set of bars that rub the peanuts one direction then other like grating cheese... the shells slowly breaks up allowing meat inside to fall thru. Hulls are blown/vacuumed off and you are left with raw shelled peanuts.",
"For sunflowers, there's a machine called a \"dehuller\" which looks like a giant disc brake rotor. The machine is spun up to well over 1,000 RPM, and the seeds are dumped in the middle (at a carefully controlled rate). The huge amount of centrifugal force from the machine throws the sunflower seed out the side and against a steel or ceramic ring around the rotor, smashing the hull apart. It doesn't get the seed out perfectly, and a lot of them end up smashed into little pieces. The smashed shells are also still mixed up and have to be separated. This is done with a series of air-based machines, and the shells are sold as an alternative to coal for heating buildings. The seeds are then sorted out by size using a machine called a Gravity Table (google it, it's too hard to explain here). The tiniest pieces are called \"fines\" and are used to make the birdfood that comes glued to plastic sticks at pet food stores. The ones that are just broken in half are called \"mediums,\" which also go to birdfood and/or oil, and the whole seeds are called \"Coarse chips,\" which are sold as food to go in multigrain bread/everything bagels, salad bars, or as birdfood. Source: Used to work in a sunflower processing plant.",
"Well, they do often break the nut meat. Then the nuts get sorted by size. Whole nuts fetch a premium. The cracked bits get sold as pieces or are ground down further."
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csl568 | How does Object Oriented Programming work? What does it do and how is it effective? | Technology | explainlikeimfive | {
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"Instead of step-by-step instructions *to the computer* about what to do, you create objects and instructions for each object for how to calculate things internally, and how to interact (externally) with other objects. For example, instead of generating this web page from top to bottom: * Write \"Get new reddit, My Subreddits, Home, Popular, All, Random, Users, etc.\" * Write \"Reddit, explainlikei'mfive, Comments\" * Write ELI5: How does Object Oriented Programming Work?\" * etc. You instead: * Create a Get_Header object, and put code inside about how to make that menu at the top, with all your subscribed reddits. * Create a Navigation object, and put code inside about figuring out which subreddit the user is viewing (explainlikeimfive) and what tabs (comments). * Create a Get_Topic object, and put code inside about getting the title of the post, and getting all the replies, and sorting them in order. * And then you create a Main object, that says, on click, get the user name, and for that user Get_Header(for user), Navigation(for user), Get_Topic(for user), etc. Advantages are that you don't have to repeat the steps for every user, you can just use the objects that are there. You can also copy and \"inherit the properties\" of objects to create more objects. The code is organized better, logically.",
"The big bois of OOP are Abstraction, Encapsulation, Inheritance, and Polymorphism. **Abstraction** basically means, when you tell this program that's a calculator 2^(4) \\+ 3 = ?, you don't know how it figured out the answer, but you know it did. **Encapsulation** is how each object has 'ownership' of the things inside of it. Basically objects can't mess with data in other objects unless you explicitly allow for it. **Inheritance** is just how it sounds, if you have a object inside and object, it can inherit the properties of the parent object. **Polymorphism** is altering the children despite what it can inherit. For example, your house (parent) has two rooms (children) in it. The air conditioning is at 75 degrees. One room inherits the temperature of the house, 75 degrees. One room as a window unit (a method/function) that allows for it to either inherit the temp from the house (parent) or you can alter it with its own ac (Polymorphism). Polymorphism is a bit more complicated than that, but for the sake of not having a long winded explanation, that's basically it. OOP is sometimes preferred because of its abstraction and encapsulation. It only shows precisely what it has to show, so its a bit more secure, and polymorphism lets you code in a lot of alternate courses of action for the program to take for certain parts of the program.",
"The idea is to take the structure of the real-world and use that to define the structure of the software. If I'm making an airplane simulation, my program is divided up like the plane's parts are divided up. It compartmentalizes change, an airline might switch to an alternative engine, but then I just replace my Rolls Royce Engine object with a new GE Engine object. This sort of change is a lot more likely that replacing all the electrical circuits, so it's a better modularization choice than having all the electrical modeling in one Electrical object. It's most effective when the analogy is strong, like the airplane case above. It's much less convincing when all the \"objects\" are made up for the software. It turns out most things we do in software today have been done in reality for decades, so it does work most of the time, but nothing's perfect in software."
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csm0mm | Why is speeds related to tech (like CPU, GPU, RAM speeds) are calculated in Hz? Why is it that we do not say how much data is processed in a given time. Like we do with wifi or network speeds? | Technology | explainlikeimfive | {
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"Hz is in cycles/second, or things that happen per second. For example, monitor refresh rates are expressed in hertz as they are # of screen refreshes per second. As such, these speed are indeed the same type of measurement used with WiFi and network speeds (also expressed in things/second, where things is data)"
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csm0n5 | Why does the TV antenna work only when touched? | Technology | explainlikeimfive | {
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"text": [
"The human body can act as an antenna in certain circumstances. What's happening here is that you're putting your body into the loop, and you're conducting the signal through the antenna into the TV. It's harmless, don't worry."
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csmhop | How do the continuously self cleaning door handles at hospitals work? | Technology | explainlikeimfive | {
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"text": [
"There is a patent for this but I am not sure if they are actually used yet. I will answer a different question, if they are made out of copper then they are not self-cleaning but they are anti-septic. Copper is like kryptonite to a lot of micro-organisms."
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csnovu | How do satellites work if they are just pointed in one direction and the earth is constantly rotating? | Technology | explainlikeimfive | {
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"text": [
"Satellites aren't stationary. They're orbiting the planet at many thousands of miles an hour. Gravity is trying to pull them straight back to earth, but since they have so much speed horizontally, they end up making a curved path. There is a special altitude at around 22 thousand miles up that the speed across the surface of the planet matches the speed the planet is going. Which results in the satellite just hanging still in the same location above the planet. We call this geostationary orbit.",
"A lot of them rotate with the Earth (called \"geosynchronous orbit\"), so they can remain over the same place for as long as possible and provide coverage to that place throughout the day/night. Other satellites might not be in a geosynchronous orbit. They might only provide coverage during certain times of day. That's why a company will launch many satellites, so that there's one satellite overhead beaming TV to your house when the other satellites are over other parts of the world.",
"Geostationary satellites. The satellite dish is pointed at a geostationary satellite. A geostationary satellite orbits at about 35,786km. They have an orbital period of 24 hours so they stay above the same spot relative to the surface of the earth"
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csnq4q | what is end to end encryption in messaging apps? How secure is the data on these apps? What are the levels of security of messages sent on different messaging apps such as WhatsApp, Messenger, Signal, Telegram, Discord, WeChat, LINE? | Technology | explainlikeimfive | {
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"End to End encryption simply means that the encryption is provided at the end points, i.e the app on the phone itself. When you add a new contact the two of you exchange keys, ensuring that the only people that can read your communications are you, and nobody else. The company providing the app can't read the messages, all they see is a jumble of random noise. because only you hold the key only you can open the messages. Of course this means if you lose your phone you can't retrieve your messages since a new phone can't get the keys of the old phone, but that's a security compromise most people are willing to take. If you have many devices logged in this issues isn't present. How secure this is generally depends on how much you trust the developers not to try and swipe your keys, but a lot of the more secure ones provide you with the code you'd be downloading, so you can verify that it's doing what it says it is doing. If everything is done by the book this is about as secure as you can get. So long as you keep your phone safe the messages are safe. Different apps have slightly different protocols and features, and you're going to have to research the apps yourself to learn what you're looking for.",
"The underpinning technology is something called 'perfect forward secrecy' which means that at no point in the transmission can any of the information derived be used to reverse engineer the encryption key. The app then decrypts the data so you can view but re-encrypts it on the device once it has been received so even if someone takes your phone and clones it, they won't be able to see the message. It is very secure, to the point that the FBI wants a 'back-door' to these technologies because you can lock even them out. They wanted to bust a guy for illegal stuff on his computer but his password was too complex and the encryption too strong and they can't get into it. It has been tied up since like 2009, in 10 years they can't decrypt this thing. I think he used \"TrueCrypt\" which I don't think is even available anymore. Anyway, these apps use something *like* TrueCrypt for the data at rest on the device and in transmission and reception."
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csq34u | How do companies like Google, Apple, and Microsoft store all our personal data? How do they have enough space for it? | Technology | explainlikeimfive | {
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"text": [
"Giant rooms full of servers and disk storage. I mean giant. Data centers measured in millions of square feet. It's called the \"cloud\" because it may be based in many places across the globe. Amazon Web Services has been one of the largest cloud computing companies historically, but the momentum is shifting towards Microsoft's Azure services these days."
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cstyf1 | Why is obscuring someone's eyes in a video or photograph enough to mask that person's identity? | Technology | explainlikeimfive | {
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"text": [
"The “triangle of recognition” is a triangle formed across the eyes then narrowing to the mouth. Take a leg off a tripod and it will fall over. Same for the way we best compare and recognize faces.",
"It doesn’t do a great job, people can still obviously go “that’s probably this guy” but because the eyes are obscured you can’t *100% prove* it. So it’s like a safeguard that it can’t be used as proof/evidence that they were in that photo.",
"It isn't anymore. It's possible to indentify someone from only a small portion of their face these days."
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csunty | How can my radio pick up different radio frequencies and turn them into music which also contains frequencies. | I know radio waves are something else but I cant get my head around how my radio is able to switch frequencies. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"You know when you look at a graph that shows a consistent wave signal? We will call that the ‘carrier frequency’, the wave frequency that your radio will pick up and recognise as a channel. In AM (amplitude modulation) radio signals, the peak HEIGHT of those waves on the graph can be used to draw another line, which is then used create a sort of second wave, which is then converted into sound. In FM (frequency modulation) radio signals, the WIDTH of the waves changes slightly, so the frequency is actually within a small given band, not just one very specific number. The slight differences in frequency are then used to create a second wave which is then converted to sound."
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cszhch | What is raytracing? | Technology | explainlikeimfive | {
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"text": [
"In the real world, a light source spits out light \"rays\" throughout the environment, with them bouncing around and with a few eventually entering your eyes. However, over 99% of them probably are not going to be seen by you, so with the limited computational power of computers, we decided that's a waste of resources. Raytracing goes effectively backwards: it shoots rays out of the virtual \"eye\" and sees how they bounce through the scene and \"interact\" with the lights. Doing that means you waste very little in terms of computational power for things unseen. It's not a perfectly realistic technique, but it's way more realistic than the typical technique used by games called rasterization."
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