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7xm9jp | What was happening to old versions of Windows that was caused that glitch were you could create a cascade of windows on the screen? | Technology | explainlikeimfive | {
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"When you're moving objects over each other in a graphical user interface (GUI), the GUI draws the top objects pixels over the bottom object. When the top object is moved off the bottom object, it's the bottom object's responsibility to \"redraw\" itself, replacing the pixels that were covered by the top object with its own. What you're seeing in that screenshot is that Windows Explorer has crashed, and since Windows Explorer is responsible for redrawing the entire desktop background, and it's not doing that, dragging a window over the desktop leaves a trail as the GUI draws the window over the desktop and the desktop fails to redraw its own pixels. **Edited to add**: these operations normally occur so fast you can't see it, you need to have something going on that's slowing down or crashing the processes running in order to see GUI drawing issues."
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7xmar4 | Two-Factor Authentication | How do apps and websites generate their codes and have so many systems to send text messages and such? | Technology | explainlikeimfive | {
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"I can't speak on the text message side of things but I can talk about the codes and how they work. First I need to talk a little bit about random number generators (RNG's). The important thing to know is that despite their name RNGs aren't actually random. What they are instead is what is called \"pseudorandom\", basically it's just a super long pattern that is so complex that even computers can't predict it just from seeing the numbers that get spit out. (Some really tough RNGs actually have several smaller RNGs inside of them all running at the same time, then use another RNG to decide which one gets to be the next number they actually put out). This is why in some games if you force quit the game and restart from a save the next few number rolls will be the exact same as they were before you quit, because it just reset to that spot in the pattern. Now each pattern is generated from a special starting number called a \"seed\", and since we already know that the patterns aren't actually random, this means that if you take the two copies of the *same* RNG and give them the *same* starting seed then they will both spit out the *same* sequence of numbers (you can see this with the \"world seed\" in games like minecraft; having the same seed in the same version of minecraft makes the game's RNG spit out the same numbers and thus generates the same world even on different computers). These synced RNGs are really what all two-factor authentication code generators are, they're just two copies of the same RNG that were both given the same seed and told \"go to the next number every X seconds\", with one copy on your phone and another one running on the game/program server. Then the game just needs to check if the number you put in matches the number they have and they know if it's you or not. As a side note for periods where you close the app and then restart it (or the server goes down) your phone (or the server) just says \"Y amount of time has passed, generate Y/X numbers to catch up\" and really quickly generates a bunch of numbers to catch up to the other copy. (After super long periods sometimes they just say \"okay, here is a new seed, lets start over\" instead).",
"In a basic explanation, two-factor authentication is something you know (username and password) and something you have. The something you have is the ‘token’. A lot of the tokens have moved recently to text messages because they assume you have your phone or mobile device. Some use email with the assumption that if you have access to the account, you can prove (enough) who you are. Other tokens include a pseudo-random number generator “keyfob” that display a series of digits. These use a quartz clock circuit to generate a display number based off a seed. On the other end, the token ID is combined with the seed and time to verify whether the numbers match. The validation system can be adjusted to allow for clock gains or losses on the token."
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7xmmzh | How are new sythesiser sounds made? | Technology | explainlikeimfive | {
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"A computer program tells the machine what shape of sound wave to produce, using a series of numbers to describe the actual height of the wave over time. Different wave shapes make different sounds."
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7xmwu9 | When an EMP goes off, can the electronics affected be replaced? | Technology | explainlikeimfive | {
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"They stop working because components within them are overloaded and burn out, short out, or explode. So depending on the item some could be repaired and others would have to be fully replaced. So with a city being attacked it would be yes, though it may take a while to get the replacement components to the city and into the proper machines. The catastrophic thing would be if an EMP happened globally (such as a strange phenomena from the sun) and this would mean virtually all stored components and the factories that make components would likely also be destroyed basically meaning you have to start from scratch building replacements by hand and that could take a long time to build back up to the same tech level."
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7xncct | What do server farms/data centers create? | Technology | explainlikeimfive | {
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"> but what does the farm actually make? Is it upping the RAM of the site? The server farm *is* the site. A website is just a series of files which are accessed remotely. They exist on a computer which is connected to the computer on which you are viewing them. The computer that holds and provides the files which make up a website is called a \"server\" (it \"serves\" the files to anyone who requests them). Big sites have lots of users and one computer would be overwhelmed. If you take a bunch of servers and put them all together it is called a \"server farm\", sort of like how a farmer might raise a pen of chickens or cows. Having a bunch of servers means the load of serving all the people who want to see the website can be split up between them and be successfully managed."
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7xnvtl | Why is violence in video games acceptable, but sexual violence is an extreme taboo? | Technology | explainlikeimfive | {
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"Everyone is used to violence and in some cases it’s perfectly acceptable to use it (e.g. when defending yourself). There are no cases where sexual violence would be acceptable, however.",
"Most games present violence in semi-acceptable situations, like war, self defense, or killing evil space goblins. Even when it is clearly criminal, the game play is much the same...villain or agent of justice, you are still mostly running around killing hordes of nameless enemies. Non-consensual sexual violence is reviled in just about any conceivable situation."
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7xo5ow | How do barcodes/barcode scanners work? | Technology | explainlikeimfive | {
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"So as others have mentioned, the light or laser is there to be reflected from the non-black parts, and the resulting reflected light is picked up by a photosensor to get a very simple image. What you probably think about is barcodes on items you buy that get scanned at a register. Those are made in a way that makes them easy and fast to handle, as they add some functions into those. First and most important is the encoding used. Each number has a specific amount of black and white lines. Let's take EAN. Each number is represented by 7 bars. If you would count them, you would not find 7 bars in any of them, but that is because each bar as a specific width and if you have 2 white bars they just appear as a slightly wider white bar. The scanner will still pick up 2 bars for that. Or 3... or 4. So how does it know how wide a singe bar is? Well that is where the beginning, middle and end comes into play. You see, those parts have 3 bars, black - > white - > black. Their width is used to calibrate the width of each individual bar. Now that the scanner knows the width, start and end, and the information inbetween, we have 7 bit per number. That quite alot of information for just the number 0-9. For those numbers 4 bit would in theory be enough, so why so much information? Well that is the next thing to make it easier and faster to handle. With 7 bit per number, the encoding was done in a way that each number is unique if read either forward or backwards. The orientation of the barcode doesn't matter, as a barcode read backwards will still result in the same scan. When reading it backwards it just needs to swap the number order as the last number will be the first that is read, but each number will be recognized correctly. With the way the setup process is done when reading the width of each bar, and the middle section, the sensor can also calculate the correct numbers even if the barcode is read at an angle. Last the middle section also allows the scanner to scan the whole EAN in 2 parts, basically scanning 1 half and then the second half in sequence. This functionality allows for a scan angle of up to 45°."
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7xqspx | What is the difference between 10H and 2,5D screen protectors? | Technology | explainlikeimfive | {
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"> What is the difference between 10H and 2,5D screen protectors? \"2.5D\" refers to a flat screen protector with a slight rounding of the edge without actually bending the sheet to follow a curve of the screen. \"10H\" is trickier to dissect. The resistance of the screen protector was tested using the MITSUBISHI PENCIL company's Hi-Uni testing pencils. You should remember the standard 2B pencil for taking tests in school. That refers to the hardness of the graphite with 3B, 4B, etc. being progressively softer. In the other direction you can get H, 2H, 3H, etc. which are progressively harder. A 10H screen protector won't be scratched by a 10H pencil. Whatever that means."
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7xr1y2 | PC Mining, What is it and how safe is it? | As the title says. Saw an article earlier today which piqued my interest and would like to know more. There is a subreddit for it, but I'd like to have a basic understanding before diving in headfirst. | Technology | explainlikeimfive | {
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"I assume you're talking about cryptocurrency mining with your PC. Headline: basically, chances are that if you live in a place without heavily subsidized electricity, you're not actually making money. One of the things a distributed ledger needs to solve is how to prevent someone claiming a transaction fraudulently. Without a central authority to verify transactions, a distributed ledger accomplishes this by verifying transactions via a \"proof of work.\" Essentially, a block of transactions is verified by solving a math problem where the input is the transactions in that block as well as the blocks that came before it (earlier transactions on the ledger) and there is no easier way to find the solution than just guessing numbers. If I create a block that has transactions I just made up, everyone else working on the ledger will ignore it, and unless I have a ton more computing power at my disposal than everyone else, people will basically say \"hey look, this guy over here is the only one with these transactions. There's way more work being done on this other version without those transactions. They're probably fake.\" In order to incentivize people using the ledger to perform this verification service they are often given newly generated tokens (coins) or a tip for verifying a block. However, the value conferred is almost certainly going to be less than the value of the electricity your computer used to verify the block.",
"\"Mining\" probably refers to cryptocurrency mining, the most popular form of which is bitcoin mining. This typically involves using a high-end gaming GPU, specialized hardware chip, or sometimes just your processor, to try brute-forcing a cryptographic algorithm to reveal the next part of the currency's blockchain. In what the computer is doing, it's very similar to algorithms used to brute force a password: basically high-speed guessing. The reason you'd use a GPU for this is that a GPU is made with thousands of simplified processors that don't have some of the advanced features of modern CPUs that make them useful for general purposes, but give you access to *really* fast speeds for doing lots of fairly simple operations in quick succession. This will, however, cut down on the usable lifespan of the GPU(s) used."
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7xr802 | How can there be a maximum compatible memory in a camera, when the memory cards are all the same physical size? | Technology | explainlikeimfive | {
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"Each byte in a memory card has a unique address (like every house on a street). The OS in the device itself (be it dash cam or phone) uses these addresses to read and right data to these bytes (like posting or collecting letters from the house mail boxes), If the maximum size of address that the OS can count up to is 32G than it will not be able to \"find\" any bytes at addresses higher than this even though they are physically there. Its like if the mailman can only count up to 32, houses with numbers 33-64 are never going to get a visit.",
"Although cards has same physical size, they need different \"software\" to access the data. There are [three types of micro SD cards]( URL_0 ): SD, SDHC, and SDXC. The 32 GB card is a SDHC card and the 64 GB is a SDXC. If the dash cam only supports up to SDHC, then it can only take cards up to 32 GB. ELI5 what are the differences: There are 99 boxes with number 1-99 assigned to them. In order to get/store things in a box, you need to say the its corresponding number. If you can only say one number, you can only get/store things in boxes 1-9. But if you can say two numbers, you get to access all 1-99 storage boxes. The dash cam can only get/store 32 GB because it only know how to say the storage locations within 32 GB limit.",
"The SD cars standard have evolved over time to increase speed and storage size The max size of the card are SD 2 GB SDHC 32 GB SDXC 2 TB So you purchased ad SDXC card when only SDHC was supported. Standard, mini and micro cards are only the physical size and and you can use smaller card in a larger port with a passive adapter card. The standard are backward compatible so a device that support SDXC can use SDHC and SD cards. But you cant use a SDXC card on a SDHC device. It looks like the max size was because of the filsystem they used SD the 2 GB is the same as the limit of the FAT16 filsystem that was used. It can also be the limit for the SDHC cards where windows have had com problems with larger partition then 32 GB on all os version FAT32. The latest SDXC card use exFAT that support larger sizes. It was by Microsoft later then the SDHC standard was set so it was not a option in that standard. There was a good reson to use FAT because all desktop computer operating systems can use it."
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7xro3n | How do hexadecimal color codes work? | Technology | explainlikeimfive | {
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"One of the ways computers store color information is Red, Green, Blue (RGB) format. What the computer does is it stores a value from 0 - 255 for each of those three colors. Some examples: 0,0,0 = Black 255,255,255 = White 255,0,0 = Pure Red 0,255,0 = Pure Green 0,0,255 = Pure Blue And all the various combinations of colors in between. As we know, computers operate in 1's and 0's. Bits and bytes. In memory and on disk, it isn't storing numbers from 0 to 255, it's storing a single byte, from 00000000 to 11111111. Writing out all the bits of a byte can be cumbersome, so hexadecimal is often used, because you can represent four bits with a single hex character, or 2 hex characters to represent a single byte. To show the difference, take a look at some of our previous examples in binary and hex: Black = 00000000,00000000,00000000 or 0x000000 White = 11111111,11111111,11111111 or 0xFFFFFF Red = 11111111,00000000,00000000 or 0xFF0000 Much more compact and simpler and easy for computers to read and interpret. In short, when you see a hex color code, the first two characters represent the amount of red, the second two represent the amount of green, and last two represent the amount of blue.",
"Hexadecimal is just a way to write numbers. Two hexadecimal digits are enough to write each number between 0 and 255 in decimal. So with two characters you can store a bit more information. For example, 8B is equal to 139 in decimal. For color codes, the first two hex digits refer to how much red there is, from 0 (no red) to 255 (fully saturated red). The next two digits refer to how much green there is. And the last two digits refer to how much blue there is. So 8B1F00 would be a value of 139/255 Red, 31/255 Green, and 0/255 Blue. That would give [this darkish red colour]( URL_0 ) that has a very very slight orangeish tint due to the slight inclusion of green."
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7xu76q | Why do smartphones have more cores than computers? | A lot of mid-range phones have octa-core processors. Yet it's quite rare to see higher than quad-core processors in mid-range laptops. | Technology | explainlikeimfive | {
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"Core count in a phone can get a bit funny, particularly with chips that use the big.LITTLE layout. In a big.LITTLE configuration there will be two cores per core but only one is active at a time. When the workload is light, it is taken care of by a weak but power sipping Little core to preserve battery life, the big core is completely powered down during this. When the workload increases the Little core will get powered down and the big core will take over. Sitting around doing nothing, the big core will consume significantly more power than the little core so having the Little one significantly improves battery life in standby mode. Your computer isn't super concerned about battery life, the sleep states of the CPU are usually good enough and it needs to be designed to handle a single task really well so having a few strong cores is significantly better for it than having a bunch of weak cores. Your phone is choosing between one moderately strong core and a few moderately weak cores, its not going to be performing any massive single threaded operation, there is always a fair amount going on on the background(compared to the intensity of the main task) that those extra cores have things to do A chip with 4 big cores vs one with 2 big cores may not show any significant performance boost, but that's really hard to benchmark on phones since we can't come close to keeping everything else equivalent"
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7xuba0 | How does a metal detector work? | Technology | explainlikeimfive | {
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"The metal detector creates a magnetic field, and then senses the field it created. Metal will affect the magnetic field, so the detector can see that the field has changed from what it sent out. Imagine wiggling your finger in a pond. Your finger will make circular ripples that expand out from your finger. If there is a duck nearby then the ripples will hit it and no longer be circular. You would be able to tell the duck was there even if it was invisible because of the way the ripples changed."
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7xwner | Is audio spyware a real thing? | Clarifying: Not so interested in advertisers (although also creepy), Could a person I know install something on my phone? [Like this guy]( URL_0 ) How would that even be technically possible? And how can it be like blocked/discovered on my phone? | Technology | explainlikeimfive | {
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"This is possible and if you have a smart phone that has the facebook app on it, most likely happening. The technology is possible because in your pocket you are carrying a device that has (among other things): -A microphone -A connection to the internet. That's it. That's all it takes. The only way to 100% ensure that this doesn't happen is to put a hard wired switch in line with your mic. More realistically, you can go through your app permissions and limit which apps have access to your microphone. [Here]( URL_0 ) is link for how to disable facebbok's acess, and you can do the same thing for all of your apps. (Except for programs like skype that have a legitimate need.)"
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7xwv78 | How is Russia, despite us knowing it is them, able to continually launch cyber attacks on the US, and there is seemingly nothing that can be done about it? | Technology | explainlikeimfive | {
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"When Cyber Attacks are blamed on the Russians, they're not necessarily being blamed on the Russian Government. The reality is, even if hacks or fake news are traced back to Russian IP addresses, in most cases that IP address is not going to lead to a government building. So, there's basically little way for anyone to tell whether that attack-initiator was some random Russian high school kid trolling or part of some military covert program. Even with all this fake news being blamed on the Russians - we don't necessarily know that it was the Russian Government that commissioned it. Russia is famous for having a large underworld of hackers (and other cybercriminals) for hire so to speak. These individuals could be commissioned by anyone, even by US politicians. For instance US politician could arrange to pay some of these cyber groups to run a fake-news campaign against his or her opposition... Everyone is quick to assume that if Russia had something to do with it, then the Russian government must be involved... when really it could just be a bunch of random Russian kids hired to do a job and have nothing to do with the Russian Government.",
"I don't really know about the topic that much(so i can't say why you're so confident), but I'm Russian and in our news they're feeding us the same bullshit about the US",
"From a technology standpoint, fighting cyberattacks is almost always a defensive action. Hackers break into your server, you patch the hole that let them in. Then they find a new hole, and you patch that and kick them out. Then they spearphish some credentials, then you go and lock down the accounts. There's not much that can be done short of major international law enforcement operations, which leads us to... The political side of the problem: nothing is being done about it because the people who are in charge don't want anything to be done about it. Twitter and Facebook don't want to crack down on the Facebook social media accounts that are used to shape public opinion and foment discord because it would mean demonstrating that a not insignificant portion of their user base is made of fake accounts (and that would mean that the value of serving ads to these accounts is zero). In Washington, President Trump has been a direct recipient of the benefits of Russian cyberattacks, so why would he bite the hand that feeds him? And since he directs the divisions of law enforcement that would crack down on that, they have focused their attention where he has directed, which in this case is mostly focused on immigration-related crimes because that's what motivates his base. Congress could investigate it, but given the fact that there are concerns that Trump's campaign directly colluded with the Russian government in advocating for and benefiting from the cyberattacks, large factions of the GOP (including the committee chairman who is nominally responsible for investigating Trump in the House) are staunch Trump acolytes who are fighting to defend him instead of trying to understand the system - by association, they are beneficiaries of the cyberattacks because it has put them into power, and they are defending that power.",
"It all depends on what one means by cyber-attacks. The so-called attacks that Russia is mostly accused of, like influencing public opinion by mass posting fake news, aren't illegal. In addition, the people doing it are located in Russia. There is no way for the US to stop people in Russia doing stuff that's not even illegal. In reality, the main reason we have been hearing so much about Russian \"meddling\" is because it has become a political argument between Trump supporters and Trump opponents. There may have been shady deals or whatever, but the cyber-attack part of it is quite tame."
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7y11zg | why do certain characters cause computers to crash | Technology | explainlikeimfive | {
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"Most likely cause is not enough input validation from the programmer. If there are input fields where characters can be entered, the program handles the input in a specific way, an unexpected value can cause exceptions or other strange behaviour. A programmer should check the input before processing it. Examples: * Switching from a left-to-right character set to right-to-left character set mid-line caused WhatsApp to crash on iOS iirc. * newline-characters in input fields where a simple textstring is expected * numbers larger than the variable that has to store it (e.g. entering \"300\" where a byte (0-255) can be stored. * Escape-characters, which prematurely mark the end of the input, everything else followed might get interpreted as code: URL_0 In most cases, only the program itself crashes, not the whole system."
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7y8q38 | Why can't modern browsers like safari tell me how large the zip file that I am downloading is? | Every time I am downloading a GitHub zip of a project I am working on, safari never knows how large the zip file is, why is this? | Technology | explainlikeimfive | {
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"Chrome does not show the size either. If I am not misstanke the reson is that size information is optional in HTTP. There is a good reson that is is optional because HTML code generated dynamically, with for example a PHP script, the transmission can start before they are completely generated. You would have to wait if size was required I suspect it is not included is because the zip generation is likely done on the fly so the ZIP file done necessary exist when you ask for it and it is generated for you, They might even start to transmit it before it is completely generated depending on how zip work. The coder had to add the size information if it was available and they did not do that. Most other zip files you download are files that already existed on the file system on the server so the standard transmit a file function on a server is used and that include the size as is it know for a preexisting file."
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7y97w2 | when hackers steal money via bank transfer SWIFT, why can the bank just reverse it back? | Edit: can’t | Technology | explainlikeimfive | {
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"Because what they usually do is transfer that money between different bank accounts hundreds of times, and then split the money into hundreds of other bank accounts and they're really hard to trace"
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7y9arg | Why can’t we recharge standard AA batteries? | Technology | explainlikeimfive | {
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"Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why can't you recharge regular batteries? ]( URL_3 ) ^(_9 comments_) 1. [ELI5 why you can't recharge normal AA batteries. ]( URL_2 ) ^(_2 comments_) 1. [ELI5 why I can't recharge normal household batteries? When they build them they charge them, so why can't I? ]( URL_1 ) ^(_70 comments_) 1. [Why can't I recharge Alkaline batteries? How are they charged to begin with? ]( URL_0 ) ^(_7 comments_)"
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7y9deu | What is a thread in programming? | As a second-semester computer science student and 5-year programmer, I'm ashamed to say I don't have a firm idea of what a thread is. I understand certain ideas, like if a method has an event listener, that "thread" will stay open until the listener is deleted. But I don't really understand what a thread *is*. Can somebody please enlighten me? | Technology | explainlikeimfive | {
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"Imagine every thread being a worker under you, that has an individual timetable. A normal program gives you one worker by default, doing the stuff the source code wants it to. Each thread you open \"hires\" another one, where you can assign work to it, splitting some calculations you need basically at the same time, for better work efficiency (for large projects you might even want to hire and fire multiple workers over the course of the project)."
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7ybqxa | Why do older television recordings have distinctive looks to them that vary by decade? | When I see old television programs, it seems like it's possible to guess the decade solely based upon the quality of the picture. I know that for a lengthy period the resolution was largely unchanged; what about the technology of the time caused the differences? | Technology | explainlikeimfive | {
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"This is to do with the type of camera/film used and as the decades move on you see an improvement in camera technology - I wish there was more to it that that but that's about it I think.",
"Analog TV dont have resolution the same way as digital. There is a set number of lines but the changes over the line are not decrete pixels. Output from a computer etc to that is on a CRT display will be defines in pixels but not the input from a analog camera. There is two distinct changes in analog TV that changes from a technical standpoint. Black and white to color and the introduction of wide screen. That is changes in the TV sets. There have been changes over time how the TV program was produced. Live programs could use tv cameras and direct transmission. The amount of light needed and the quality of the cameras changed over time. For prerecorded TV you used 35 or 16 mm film in the beginning. Over time cameras that used video tape and later digital storage started to be used. Image quality was better on 35mm film then video tape and the way it was lit and how the camera works will result in difference how the image looks. TV that was creased with 35mm film can result in beautiful HD and even 4K video because the film has even higher restitution that that. So what you see can be better then it ever looed in the past"
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7yc7tj | How do holograms appear closer to the viewer? | I don’t know how to explain it exactly, but the image in the hologram display of the Lykan Hypersport seems closer when you look at it. How does that work? | Technology | explainlikeimfive | {
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"Your eyes can‘t see distance. Instead both of your eyes see slightly different views of the world in front of you. The more those views differ the closer your brain thinks an object is. That‘s what you perceive as distance. Holograms like the one you described use optical effects to show a slightly different image depending on the angle you look at it. So your brain thinks the object must be closer than it really is, because the images differ more than usual for the actual distance."
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7yevna | Why we don’t generate electricity from sound waves while electricity is needed to produce a sound wave ? | Technology | explainlikeimfive | {
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"We do generate electricity from sound waves. That's how a microphone works. The problem is that sound isn't powerful enough to create a enough electricity to be useful for anything other than capturing an audio signal. Even with sophisticated microphones we need to amplify the signal a lot to make it useful again.",
"Even very loud sound carries very little power. The total sound power generated by a full symphony orchestra is about [1 watt]( URL_0 ).",
"A loudspeaker converts electricity to sound - I assume that’s what you are referring to. A loud sound will in fact move the speaker cone and generate some electricity in the speaker coil, so it does work in reverse. Theoretically, then, we could generate electricity from sound. It wouldn’t be very efficient, though, since the level of sound required to generate a meaningful amount of electricity would be incredibly loud."
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7yhxk3 | How did computer hackers do their hacking back in the 60s and 70s? | I realized that I know next to nothing about computers from back then, so I was wondering, for example, how a hacker from back then would hack into a business' computer? Like would they have to be on site, or could they do it remotely? Also, how easy was it to hack those old IBMs from that era? | Technology | explainlikeimfive | {
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"The vast majority of hacking in the pre-internet days relied on physical access to the system... as that was the only way to access it... or by manipulating someone with physical access to it to do something to it (knowingly or unwittingly) Even today, physical access to the system is often how a lot of hacks take place, there's just no substitute for ease of actually having physical access. Even many newer big name hacks, such as at least one of the Sony hacks and stuff like Stuxnet both were done with physical access.",
"You go back that far, the computers you find are going to be huge, possibly run on punch-cards or other physical media, and almost certainly wouldn't be connected to a network- the first message was only sent over ARPANET in 1969, and commercial internet services didn't show up until the end of the 80s. The computers you'd find in the 60s also had so little computing power they were essentially room-sized calculators, and had memory to match. In the event you wanted to steal data from a big bank's computer room, you'd be looking at stealing the stack of paper the computer printed to output its data (because screens weren't really a thing yet), or possibly the punch-card or magnetic tape containing a program, and not anything on the computer itself. If you're looking for something closer to the image we have of \"hacking\" today, you might instead look at **Phreaking**, which was the practice of tricking, exploring, and compromising telephone systems. You had stuff like people figuring out how to get free long distance calls from payphones, whistling at specific tones to trick the telephone system that listened for those sounds, hijacking unused voice mail boxes and party lines for communicating like an early chat room, as well as considerable amounts of social engineering to get information from the people they called. They had fun tricks, like coveting a specific whistle that came in a toy in boxes of cereal that blew at the exact pitch that would trick AT & T's systems into switching into an open carrier line that would allow free long distance and international calls.",
"There wasn't really any hacking in the 1960s as hacking actually meant improving your computer not breaking into it. In addition most computers existed within closed networks so that there was little or no access from the outside world and people didn't have easy access to home computers, network access, and the internet didn't exist. It wasn't until 1971 that a guy worked out how to spoof the AT & T telephone system into giving long distance free phone access that hacking really start - who would use their own phone line, and pay for it, to hack a computer.",
"First hack I remember from college (about 1977) involved the schools mainframe. Terminals were “dumb” where Computer Science students login to the mainframe thru a very simple ASCII screen or TTY terminal. Hacker I knew wrote a simple “Man in the middle” program simulating the login screen, capturing student login passwords and passing info to his account, before connecting to the mainframe. He never did anything with the info except notify the school what was possible - after he graduated."
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7yi5f4 | How does a pinhole camera take pictures when its just a box with film inside of it? | Technology | explainlikeimfive | {
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"Light comes in, it hits the film, reacts with the film, and leaves an image via chemical reaction. The pinhole means that each bit of the film only gets light from one angle. You don't need a lens, you don't need zoom, you don't need a shutter if you manually cover it, you don't need a viewfinder. That's all you need for the fundamentals of a camera.",
"> How does a pinhole camera take pictures when its just a box with film inside of it? In order to form an image on the film (or our retina) there must be light from one direction falling on one patch of the film, and not light from other directions. Without anything in front of the film light from any angle up to 180 degrees could hit any part of the film. When light passes through some materials it will refract or change direction. This is referred to as \"refractive index\" and you can notice this when putting your hand underwater. You can see that while your hand looks pretty normal it is offset from where it should seem to be, due to this redirection of light. What a lens does is use this refraction in different amounts to make it so light from only one angle is landing on the film, and that it is ordered so that it forms a clear image. All this light is collected from the area the lens covers and all the other angles are blocked out by the body of the camera and lens. A pinhole camera achieves the same goal by only have a tiny hole through which light can pass. Because there is only this one aperture through which light can pass any patch of the film cannot help but only get light from one angle. The downside of this is that the pinhole doesn't allow a lot of light through it so the camera has little to work with to form the image.",
"Lenses focus light by redirecting the rays from distant points to the same point on the focal plane (where the film sits). The pinhole camera has a similar effect by limiting all rays from distant points to a single point on the focal plane. Much less light gets through so the film must be exposed for much longer. You can see the effect by making a pinhole in a card, and letting the sun shine through it onto a sheet of paper.",
"Ahoy, fellow redditor. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do pinhole cameras work? ]( URL_6 ) ^(_2 comments_) 1. [ELI5: Why (not how) does a camera obscura/pinhole camera work? ]( URL_2 ) ^(_7 comments_) 1. [ELI5: How does the pinhole camera work to see the eclipse?? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: How does a Camera Obscura work ]( URL_0 ) ^(_11 comments_) 1. [ELI5: How cameras work. How do they capture an image and print it? ]( URL_4 ) ^(_14 comments_) 1. [[ELI5] this explanation of the pinhole effect and solar eclipse 'shadows' of tree leaves. ]( URL_3 ) ^(_1 comment_) 1. [ELI5: Why are particles in circular or oval form when a camera is unfocused? ]( URL_5 ) ^(_4 comments_)"
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7yifzx | What creates the “zooming out” effect you see when you shut off a TV or computer? | Technology | explainlikeimfive | {
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"If you mean on really old CRT screens, the whole picture was drawn by a single point flying across the screen very fast, horizontally, then stepping down a vertical level and repeating. When you turn it off, the inputs driving that beam go to 0v. The outputs of that beam are at high voltage so take a little while to drain, causing the beam to sort of sit on one line, which eventually shrinks to a point, before the power source of the beam dies too.",
"The image in a CRT monitor is formed by shooting electrons at the screen. However, all electrons are shot at the center of the screen, and are diverted to their correct position by coild creating a magnetic field. As power is lost (which takes a bit of time, because the power unit has capacitors, which acts as reservoirs for electric power, to smooth out the current), these coils get weaker, and the electrons are diverted less and less, and eventually just hit the center of the screen, but by then, the monitor is usually shut down anyway.",
"This is no longer really a thing, because the kind of display - really old-school tube-based TVs - no longer exist. The only reason you are likely to see it is that some people designing displays like how it looks (they're old, and their grandparents had such a TV), and so they program their computers to display a zoom-out animation before turning off the power."
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7yjfd5 | What is a hash-table? | Relating to programming. Pretend I know nothing about programming or anything relating to what a hash-table might be. From my research, you take a value, then assign an array to it to be referenced later. But idk and still don't really understand. Thanks in advance. | Technology | explainlikeimfive | {
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"A hash table is a data structure that stores data. It's a good compromise between speed-of-access and memory usage. Let's pretend that you're 5 years old and you have a bunch of friends. You want to make sure that you say \"happy birthday\" to each of your friends on their birthday. What you have is a bunch of flash cards; each card has the friend's name and their birthday (e.g. \"Harry - July 31\") However, you have a lot of friends, and therefore, you have a bunch of cards. Today is February 19th; how do you know which friends are having their birthdays today? If you take a naive approach, you might decide that, well, you could just go through every single flash card and look for people whose birthday is today. That works, but it takes a lot of time to go through everyone on the list. A very powerful trade-off that you can do is you could, in theory, create 365 buckets; one bucket for each day of the year. Then, as a one-time step, you put each person's card in the correct bucket. Then, on any given day, you can simply look at that day's bucket to figure out who is celebrating their birthday. This works, but while it is super fast, it takes a lot of space. (It requires 365 distinct buckets.) If, hypothetically, we lived on Pluto, then there would be over 90,000 days in a year, meaning that you would need over 90,000 buckets to implement this strategy. A hash table is a trade-off between these two extremes. Suppose, instead, that maybe you just had 31 buckets. One bucket for each possible day of the month. Then, on any given day (e.g. today is February 19th), you would go look in the correct bucket (in this case, the 19th bucket). Now, the 19th bucket will actually contain people whose birthdays are on Jan 19, Feb 19, March 19, ..., so you'll still have to double-check to only find the people that are Feb 19th birthdays, but you've still significantly narrowed down the list of people you have to look through.",
"Your basic understanding is correct. The non-technical ELI5 answer is: A hash table is a bunch of buckets. You decide on some method for what things go in what buckets. When you want to store something it's fast: you apply your rule, then that tells you what bucket to put the thing in. When you want to retrieve something or check if it's stored it's also fast: you apply your rule which tells you which bucket it's supposed to be in, then check that bucket. This makes hash tables really good for storing collections that have no ordering to them. ***** The somewhat technical answer is: A hash table is a type of collection--some group of elements. More specifically, it's usually used to represent a set: a collection of elements with no specific ordering and with no repetition. The set {3, 4, 5} is the same as the set {4, 5, 3} and the group {3, 3, 5} isn't a set because it repeats the 3. A hash table is implemented as a form of map. In a map you have keys and values. Given a key you should be able to find the one and only one value that it maps to. In a map you have a *set* of keys and a *set* of values, as well as a *set* of mappings. A hash table is an efficient, novel way of storing and retrieving these three sets. This is done by making the mapping be a function. It doesn't much matter what the function is, but ideally it's fast to compute and the output will cover its entire range for the expected input (e.g. if the output is a number from 1-100 then it shouldn't give seven 50% of the time). The keys are all of the possible outputs that the hashing function is allowed to have. The values are simple lists of whatever kind of element you're trying to store (often implemented as linked lists; that's another similarly-sized answer). In computer science it's often a concern that certain operations be quick. The way we describe what \"quick\" means is by looking at how long it takes and then looking at how much longer it'll take if you tweak various parameters. For example, to find an item in an unsorted list you'd have to look through the list one element at a time. Double the length of the list and you'll need, on average, twice as long to find what you're looking for. By comparison, if the list were sorted then you could look for an item similarly to how you look up a word in the dictionary: jump to a middle position, see if you need to go forward and back, then refine your search area. This can handle large lists much better. A hash table is nice because it is a set that is very fast. When you go to add an element to the table you first compute the hash of that element. This is fast and never gets slower as the hash table gets fuller. That tells you the key, from which you can quickly find the value (i.e. the location where a simple list of elements is stored). If you've sized your hash table right then that list is empty or nearly empty, so it's fast to add the element. Similarly, when you go to retrieve an item you compute the hash of that element (still very fast) and that tells you the key (very fast) which in turn tells you where the list of elements is (again, very fast). That leaves you with a short list of elements to search through; ideally only one or zero elements are in that list so it's also very fast."
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7yno95 | How does computational propaganda work? | Someone was explaining to me that the Russian involvement in the US election is called "computational propaganda". How does this work specifically and how is it currently being used? | Technology | explainlikeimfive | {
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"If someone puts the same message everywhere you go on Facebook, and you do need to appreciate that this was a Facebook campaign, you ignore it after a time or two. It generates far more interaction, sharing, and impact when you respond to posts like a person. The evildoer posts something, and then reacts to every comment they get. This makes them seem more \"human\" and thereby interesting, even if the responses are little more than Eliza-like parrots of canned phrases."
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7yoaie | How do movies get that distinctly "movie" look from the cameras? | I don't think it's solely because the cameras are extremely high quality, and I can't seem to think of a way anyone could turn a video into something that just "feels" like a movie | Technology | explainlikeimfive | {
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"It's a combination of all of the following things: Frame rate of 24 frames per second (with a shutter speed of double the frame rate at 1/48) Cinematic aspect ratio (Widescreen) Fantastic and purpose built lighting for the scene High dynamic range image capture Cinematic color grading and contrast adjustments Edit: I forgot lenses and everyone suggesting it in the comments to my post are completely correct. You can do it with cheap lenses, but fantastic lenses really do add to the look. Edit 2: [more detail about these points in a following comment here]( URL_0 )",
"I am a cinematographer.. and while these comments are somewhat accurate, the simplest and most fundamental answer is dynamic range. Yes lighting, framing, sound etc is extremely important, but the real film look you refer to is the dynamic range (data caught in the very highs and lows of the image). Edit: I have had a lot of people contacting me to see my work, for tips on becoming a DP, and generally disagreeing with my point. Here is my showreel: URL_0 Most of this was filmed with pretty cheap cameras.. some shots even with very dated Canon DSLRs which are no longer made.. and I’d like to think most of it is quite filmic, so yes, dynamic range isn’t EVERYTHING - but I feel it’s important. I.e if you were to take an Alexa outside and match it to the iPhone’s field of view, same framing etc, the thing that makes the Alexa look so sexy is the dynamic range. Secondly, a lot of people have mentioned ‘aspect ratio’. This is confusing; The CinemaScope LOOK is far more important than just adding black bars over footage. You can see in my showreel that the whole thing is in 2.35 aspect ratio, but only a handful were actually anamorphic. I cropped everything to that ratio though to keep it consistent - and I guess it does add a cinematic illusion - but it is just essentially throwing away information and I wouldn’t really encourage it, even though I used to do it all the time. Thirdly, for aspiring cinematographers and filmmakers; go out and shoot ! Practice, learn, and improvement will be an inevitable byproduct..you need passion (as with anything) to continue with it, and grow. I am still very small time and ‘amateur’..I have a long ways to go. Watch. Be inspired, and develop your own creative flair. Ps. A lot of people are also asking who I admire.. If I had to choose one person whom I felt really advanced cinematography as an art form, I’d probably choose Jack Cardiff; His frames are really particularly crafted, with amazing attention to detail. He also respects colour and light to the highest degree, which of course trumps dynamic range, colour grading, aspect ratio and all the other technical nonsense we’re talking about.",
"Firstly, as an aside, the quality of the lens is much more important than the quality of a camera. All the camera body is doing is interpreting the light coming through the lens, so a crap lens on a great camera is still going to provide a crap image. Secondly, that look is the result of the art of the cinematographer. The cinematic look isn't really something that can be defined in a series of instructions, but the biggest factors are artful lighting and professional color grading. I've seen cinematic cellphone videos and bland scenes that look like generic YouTube fodder shot on $36k Alexas with $150k lens kits. Some people will try to tell you that it's about the frames per second or any other specific camera setting, but there are countless exceptions to whatever rule is proposed. Of course, those settings are part of the art, but it's the combination of how the director of photography plans and executes the shot. Movies, television, and viral videos all have their own conventions and go-to techniques that give them each a specific look that can be hard to put a finger on. Edit: I didn't say crap cameras are wonderful. I said even a great camera can't make a wonderful image out of a rubbish lens. I'd rather have a C300 and a set of Cooke Panchro Classics than a C700 and some bargain basement lenses.",
"I watched The Room recently and was struck by how bad the lighting is. Watching an extremely poorly lit movie like that will give you an appreciation for just how much work goes into properly lighting a scene.",
"To caveat off the original poster. Why is it that tv shows and soap operas look so different? Different budget? Different cameras? Different style of cinematography? I’ve noticed for years and I just can’t figure it out.",
"Watch the later Hobbit movies. They used a different (faster) frame rate and so it looks very different than your standard 'movie' feel. I remember watching one of them in the theater, and as soon as I saw the characters walking around the town, I thought to myself, \"This looks like someone recorded this on home video.\" That's exactly the effect of the high frame rate - it looks like someone just captured it in real time. A lot of critics at the time even complained that it looked like actors on a set, but some like it and said that it made it feel more authentic. So I guess it's up to the viewer.",
"ALTERNATIVELY: how do soap operas get that distinct crap feel?",
"Another reason not yet mentioned is that many films are made using an anamorphic lens. The aperture is oval, rather than circular. A typical videocamera, smartphone, or DSLR use spherical lenses. Your mind associates the anamorphic \"look\" with cinema. If you Youtube it, you'll find comparisons of the same shot made on both types of lens, the difference is quite noticeable.",
"Anyone prefer the gritty look that moves had in the 80s? Is that from \"old\" film or did it look like that on the big screen too? DAT GRAIN",
"The main difference is that movies are shot at only 24 frames per second. This gives a non-natural look to the motion that's quite different from 30-60 fps television.",
"Similar question - why does live sport look 'different' when in different countries? I'm in the UK, watch US sports frequently but when a game is live in London, on TV it doesn't look the same as when in the US? Noticed this for NFL, NBA, WWE etc",
"set your camera to shoot at 24p with a shutter speed of 50 to create that cinematic motion blur. You can also do a bit of color-correction in post to give it a mood or feels. To me, the only thing that separate the pros from amateur is controlled lightings. Hope this helps :) Source: I make Cinematic videos on YouTube for fun. Edit: my YT channel name is mk_dust",
"Huge combination of things. Frame rate, color correction. Depth of field, how its framed/shot, lens type, camera, lighting and even shooting it on film usually has more punctual colors and otherworldly vibrancy. Though film look can be pretty well replicated digitally with skilled enough teams.",
"People underestimate how important lighting is. A good example is watching newer/amateur YouTubers vs seasoned ones. It just looks more professional but you can’t quite put your finger on what it is.",
"The biggest difference between cinematic and non-cinematic is not the tools like camera and expensive lenses - these are just tools that help but don’t make “the look”. The big ones are lighting, composition, staging, production design, and costume design. These all controls obvious things like contrast, color temps and composition but things like production design and costume have to be crafted into the color design of the film. And above all, all these decisions are for STORY. In a nutshell, nothing is hap hazard in movies. No lut or color grade can make something not cinematic look cinematic - it takes a talented village. To achieve a “cinematic look” one must have a story purpose to make all these decisions and more. Then in the end, it comes out cohesive and well-thought out - something more, beyond, something full of creativity. That undefinable “cinematic feel” is many creative decisions towards a single direction lead by story.",
"I would say it is down to good lighting and the best of camera lenses. Seen some old camera glass that instantly makes your photo's look as though they are from the 1970's. Movie budgets mean they can use whatever camera and lenses they choose.",
"I have a shard that I kept from a broken filter that one of the ACs accidentally dropped during the filming of a typical modern Hollywood TV show (think HBO or Netflix). The cameras (Arri) have a bank in between the lens and sensor for 4? or 5? of these large glass filters, and for most shots they'll be filled with a couple of diffusion filters, and maybe an ND filter to balance the light. The filter shard that I have comes from a filter that you can't buy commercially, but there are similar ones out there that cost over $500 dollars for a single piece of glass. They are actually two panes of glass with a thin layer in between that contains a particular diffusion pattern, and you can see the \"bubbles\" of it if you look at it in the right light. Now I'm not saying that this piece of glass is necessarily *worth* 500 bucks; you could get a very similar effect on a much simpler piece of glass, but I'm using the filter glass as a metaphor for what people think of as \"the movie look\", because it's not really one thing. It's everything. A lot of people put a lot of emphasis on their glass because of the almost imperceptible change it does to the pixels. Even if they can't necessarily see what makes it difference, people trust that it's there. There is a look (mostly in Hollywood) that depends on a lot of people knowing how to do their jobs properly, and having access to appropriate levels of technology at the same time. The cam op knows how to use a modern 6k or higher production camera, the dolly grip knows how to use a hyper-functional, top-class dolly system, the gaffer knows how to produce beautiful and quality lighting setups, the cam op, the DP and the director know how to frame, block, and arrange scenes to portray information in a \"quality\" way. There's nobody on set that isn't involved in the creation of the \"move look\". The DIT is able to determine the right light parameters to encode the data and pass it on to the editors who know how to tweak the raw data and color it in a modern and stylish way. You could talk to any one of these people and get an argument about what a \"quality\" setup is, and what their idea of a \"movie feel\" is. And guaranteed, each one of them feels like *their* part of the process is the most important. Naturally. And think of the other departments, too. Can you imagine what flat sound does to an otherwise \"quality\" film? Makes it amateurish and unwatchable, of course. Sound design is probably the best way to improve quality on a film, as far as I'm concerned.",
"As others have mentioned, but I feel the need to emphasize, it's the framerate above all else. To test that, all you need to do is try to watch a movie on a modern TV with frame smoothing turned on. Despite everything else (lenses, aspect ratio, lighting, framing), it will look like a soap opera.",
"Why do most expensive tv shows lack that feel, but shows like LOST did ( one of the main things that caught me about lost was how movie like it felt). Also there's a huge difference in the walking dead season 1-7 and fear the walking dead season 1 and 2 (3 upped the quality alittle)",
"I wondered about this a while ago. I found that the reason a movie feels different is mainly because they use so many different camera angles. Also they stabilise their cameras very well. In addition they keep the subjects in focus and the background kinda blurry if you know what i mean. This might not be what you were thinking about, but yeah i tried.",
"Y’all are crazy saying it’s not the frame rate. This is exactly why new TVs with the “pro-motion” feature make everything look like a reality show. The TVs are interpolating new frames to insert between the recorded frames, creating a look that is closer to real life and farther away from the movie look. Great for sports, terrible for everything else. The lighting, depth of field, and color timing are untouched by this feature and yet nothing looks like a movie anymore. Conversely, I can shoot in 24fps with no consideration for lighting, color, or depth of field and it will still look like a movie. Maybe a shitty movie. But a movie nonetheless.",
"DEPTH OF FIELD. Also, good lighting and 24fps frame rate. And talent. Really, that's the vast majority of it. Good instructions and tips can be found at D4Darious on Youtube. If you have a DSLR, you can pull it off without much of a problem, google up how to change your camera settings to 25fps (close as you can get with most DSLR's) and get good at using the manual focus. Separate the subject from the background, and download a copy of Davinci Resolve. Everything else is a learning experience.",
"The biggest difference between a professional film and a video you shoot yourself (aside form much more expensive equipment) is lighting.",
"There's a lot that goes into it - lighting, sound (most of it replaced these days), camera angles and movements...but also a lot on the back end, with [digital grading]( URL_0 ) and CGI effects."
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7yp586 | Why do some floating-point operations result in long decimals? | As an example, 1.2 - 1.0 = 0.199999999999999996 | Technology | explainlikeimfive | {
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"Because not all numbers can be represented precisely in binary, just like not every number can be represented precisely in decimal. For example, `1 / 3 = 0.333333333333333333`. We can't write \"a third\" in base-10 decimals, we have to approximate it. And the same is true for base 2 numbers. Just like we can't write \"a third\" in base 10, we can't write, for example, \"a fifth\" in base 2. So it has to be approximated, and 0.199999999999999996 is the nearest number that *can* be represented given the number of digits available."
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7ypnv7 | EFI vs. BIOS | I don't understand why this difference was developed, or what the fundamental differences are. How does the BIOS screen look on an EFI machine, and is it accessed the same way (F12, F2, Del on boot, etc.)? Explain like I'm five! | Technology | explainlikeimfive | {
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"the Basic Input/Output System (BIOS) is very old technology, first used in the mid 70s. It's basically a middleman between your operating system and your system-specific firmware at boot; it would load all of that data into your operating system's programming so that it could interface with your hardware. For a long time, BIOS was a good-enough way to pull those components together; disk drives and hard drives were slow and most of your boot time came from reading things off of storage media; up until about the mid-2000s, your BIOS process was a very small percentage of your overall startup time. Starting around the time that solid state drives came along, however, this changed; a full Windows install could be loaded from a SSD in a matter of seconds, and suddenly a 10-30 second BIOS boot was the bottleneck between \"press power button\" and \"usable computer.\" So EFI/UEFI was developed to be a more modern version of BIOS, by and large; Because BIOS has been a huge and integral part of computing for so long, UEFI typically doesn't exchange the way we interact with boot settings (ie: f12/del/f2 on boot). UEFI also allows for remote diagnostics and repair of computers that works even when the OS is hosed or non-existent, which is really great if you need to work on a server that's in a data center in another state."
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7yqb2l | Microsoft has announced they’re ending support for push notifications in older versions of Windows Mobile. How can they do this and why would they want to? | Is having push notifications enabled resource intensive for the operating systems providing them? I kind of assumed it was up to the app developer to implement them | Technology | explainlikeimfive | {
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"Microsoft seem to be fed up of supporting anything mobile related. Try working with Windows CE5."
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7yqdde | NYC Subway Signals | Those of us who live in New York are quite used to hearing the MTA state that we are experiencing delays due to “signal problems”. Could someone ELI5 how these train signals work, and why they are so prone to failures or delays compared to newer signal systems? | Technology | explainlikeimfive | {
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"Train signals are part of a block system to prevent collisions. Since trains often travel fast enough that they cannot stop in time when obstacles become visible, there has to be some control to prevent a stopped train becoming a hazard to following trains. This usually takes the form of dividing a rail network into blocks of track. Only one train will be allowed to enter a block at a time, and the next train will be stopped at the entrance until the previous train is confirmed to have left the block. Obviously, that requires some signal to be sent from the end of the block to the beginning, saying that the block is clear. If the signaling system is broken, then there's nothing saying the block is actually clear. In this case, it may require trains to check in through some alternative system, maybe calling in on a radio to report their location. In some systems, trains may still be allowed to travel at greatly reduced speed, such that they can stop if an obstacle becomes visible. In the US at least, that usually only applies to freight traffic, not passenger trains. As to why this is unreliable in New York, who knows. It is one of the older subway systems in the US, and to my knowledge has never really been rebuilt, just updated. Retrofitting newer technology into old infrastructure is likely to be the problem."
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7yqnqt | How does stack smashing work? (C++) | I'm having trouble understanding how stack smashing works (c++). I've tried reading [Smashing the stack for fun and profit]( URL_0 ) and I'm still not understanding how its supposed to work. It would seem like this article is out of date as it was written in 1996! Seems like modern operating systems randomize the stack addresses making stack smashing incredibly difficult. So hows stack smashing supposed to work in 2018? | Technology | explainlikeimfive | {
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"> It would seem like this article is out of date as it was written in 1996! It's old, but I wouldn't say it's out of date. It still describes the basic mechanism well, it's just that to make the exploit described actually run on a modern machine you may have to disable certain stack protection mechanisms first. > Seems like modern operating systems randomize the stack addresses making stack smashing incredibly difficult. This is called address space layout randomization. It is designed to make a buffer overflow difficult to exploit because you don't know where code placed on the stack will end up in memory. It isn't a perfect solution, however. One approach is to bypassing ASLR is to simply guess the target address. You can use what's called an NOP sled, where you prefix your shellcode with a long run of NOP instructions. This increases the target area, because if the CPU lands on any one of those instructions, the shellcode gets executed. You can also place multiple copies of the shellcode at different locations in memory. This becomes much more difficult if DEP is also enabled, because then you can't load any arbitrary code into memory."
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7yqyeq | How do movies hide cameras in scenes shot in front of mirrors? | Technology | explainlikeimfive | {
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"Hi! Visual effects artist here. Often times when cameras are visible in scenes (which happens more often than you’d think because big budget movies use multi-camera set ups) we remove them the same way people remove blemishes on the skin when editing photos, except for every frame of that scene. There is a multitude of ways to achieve this, usually we just recreate what is behind the camera by digitally painting it in, sometimes frame by frame. This is indeed as painful as it sounds. There is a whole department in visual effects houses dedicated to cleaning up scenes before putting CGI in (more often than not we don’t use CGI for these jobs to save money, we just paint as you would inside photoshop and track it in so it moves with the camera in the scene). We do everything from painting out wires for stunts, removing cameras from the set, removing people that don’t belong in the shot, cleaning up bad green screen to removing markers placed for tracking. This work can take anywhere from 2-4 months for a 3-10 second shot depending on what needs to be removed. This is oftentimes why in lower budget tv shows you see really poorly done VFX. Just finished work on BladeRunner 2049 & am now working on Deadpool 2! It’s really awesome to see people show interest in this kinda stuff. Cheers mate! Hope that all makes sense!",
"My favourite example of a mirror trick is in Terminator 2, the scene where they open the T-1000's head to extract the CPU. This was pre-CGI, so in the foreground (where you can see the head being opened) is a prosthetic, being operated on my Linda Hamilton. The mirror is actually glass, with Arnold Schwarzenegger sitting behind it. Operating on his head? Linda Hamilton's twin sister. Obviously not something you could use for every film...",
"There is no single trick, they use what works best for that particular scene. A lot of the time, they just carefully plan the shots so the camera stays hidden. The mirror may not be real, and the image in the mirror may be CGI. They could edit the camera out from the footage after the fact.",
"The current American Airlines safety video has a few scenes where they are using mirrors. In part of the scene you can barely see the hole in the mirror where the camera lens. They do a good job of keeping the actors in front of it."
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7yqyu6 | (1961/Kennedy proposes a man on the moon... 8 years later, Armstrong walks on the moon. As of 2016, China is projected to have a man on the moon by 2036.) Why is it taking so long to achieve manned lunar flights in an age where space technology and safety efforts are so much more advanced? | Kennedy proposed getting a man on the moon and back to Congress in 1961. Eight years later, in 1969, Neil Armstrong and crew landed not the moon and returned, following with several trips to and back made in a short period of time after, before the Apollo program ended in 1972. This appeared to be a good system of getting people to and back from the moon with the technology that was available at that time. It appears the only reason these missions were stopped were due to financial cuts and issues of the like. How is it now that with China preparing a lunar mission for some time now, with an estimated departure date of 2036. Why is it taking so long? The time of its vague announcement in 2016 to projected fruition is basically 20 years. Double the time that 60s era computers and astronautical scientists needed then. The technology and safety efforts that sent the men to the moon in the 60s and 70s could have only been perfected, fine tuned, and strengthened at this point. (This may be inaccurate, but I've been told many times that a modern day calculator has more processing power then the Apollo computers did...) I know finance is a huge factor, but is it really the only factor? And is it even a factor for a superpower like China? Safety is important and needed, but travel anywhere is not without its risks. Money is important and needed to fund projects like this, but there are still funds sending rovers and rockets into the cosmos gathering information and such. So whats to stop anyone from funding missions that can actually equip passengers again? It appears from a civilian perspective that 90 percent of the scientific ground work has already been laid, but you'd think with these time lines that they are starting from scratch. | Technology | explainlikeimfive | {
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"The US threw an absolutely astronomical amount of money and resources at rocket technology in the 1950's and 60's. It was, by far, the highest priority in US defense R & D for a decade or more. A space program isn't something you can buy off the shelf, even in 2018. Just building up the institutional knowledge takes decades. The technical challenges are also huge. Remember that China did not produce its first domestically manufactured ball point pen until 2017 because they didn't have the technical capability. Manufacturing is hard. Manufacturing a moon rocket is incredibly hard.",
"There are a couple of parts to your question, I think, that are two distinct things. The reasons why China is having trouble getting to the moon *at all* is that if you haven't done it before, it is really really hard to do. The reasons why places that *have already done it* are *not* sending manned flights to the moon is simply that there's no need anymore. We've got about as much scientific knowledge from the moon as we're going to get, and we've already proven we can do it. At this point, it's more cost-effective to send drones and probes than it is to send people; drones, rovers, probes, and other autonomous or semi-autonomous robotic vehicles are, simply put, lighter than humans and all the things humans require to survive, and saving on mass is *king* when it comes to saving money on space flight. (every kilogram you put into space with most rockets, costs in the range of tens of thousands of dollars; the Falcon Heavy was great because it's getting a per-kg cost of under $2,000). So China can't do it sooner because they need to pour a bunch of time and money into the technology to manufacture a rocket that can do it, and also into the R & D needed to design such a rocket. The US and other space-faring countries don't do it because it's cheaper and easier to send unmanned vehicles.",
"there's alot of knowledge of how to do it. but why do you do it? why spend billions of dollars to do it? back in the 60's, it wasn't to advance science. it was to beat the communists. because the communists beat the US to first human in orbit. it was a big dick waving contest. nowadays, we know alot about the composition of the moon thru automated probes. there's no reason to send a human there.",
"The tin-foil brigade will say we never walked on the moon, but I think you have your answers in other posts. It's not cheap -- monetarily or to resource -- and the big target these days is now Mars since no one else can now say they were the first to the moon."
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7yqyzf | What technology do big companies use to make shopping carts lock after a certain distance from the store, and how does it work? | Technology | explainlikeimfive | {
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"it's very low tech. there's a battery operated latching brake on the wheel that receives a radio signal from either a broadcast beacon or strip on the ground. once the receiver stops getting a signal, it locks the brakes."
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7yrcyt | If faucet handles are covered in bacteria why don’t hospitals and doctors’ offices use motion sensing sinks more? | Technology | explainlikeimfive | {
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"A lot of them do, but its a fairly hefty expense. Easier to use hand sanitizer nearby, and wash hands properly",
"Many do, or sinks for areas for sterile procedures have pedals or knee yokes. Most hospitals I’ve been in have the long handles so you can turn them off with your elbows, though."
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7yt5iv | How did they add text to movie scenes (ex. In the credits at the beginning of an old movie) and TV Shows before computers and digital editing? | Technology | explainlikeimfive | {
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"In the Star Wars films, they painted the words on a piece of glass and then ran the camera across it at that angle you know and love.",
"They filmed the credits which were printed on paper, then used dual exposure to print a new negative which contained both the credits and the movie scene."
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7yvcj6 | the difference between a regular computer, a server and just a hard drive with wifi capability? | Very confused | Technology | explainlikeimfive | {
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"E: This answer describes the hardware layer, mostly. Software can be \"a server\" too, but that's explored further down the thread. A server is *any* computer that's running server-software. That *can* be a regular computer, but is more often a dedicated machine, with hardware choices suited to the task. A wifi-enabled hard drive is, technically, a storage server - but most people don't call it that, because \"server\" usually implies that the device in question is *capable* of running arbitrary software, even if it doesn't *do* it."
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7yy2sj | Why do computers have a discrete GPU instead of one very powerful CPU which performs all the necessary calculations? | Technology | explainlikeimfive | {
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"A CPU is very good at performing individual tasks very quickly. However, it is particularly piss-poor at simultaneously performing many, many, many tasks. This sort of performance is very useful when rendering scenes. A GPU has many, many, many cores each of which is much less powerful than a CPU, but is much better suited to rendering. Furthermore, the hardware and drivers are specifically optimized for graphics rendering, whereas CPUs are more general purpose. So your CPU is one really efficient hard worker that can get 10 times more done than anyone else at the factory and a wide range of training, but the GPU is a team of 10,000 workers that are pretty worthless on their own but as a team can work on a lot of things together at once.",
"A CPU is a very open ended device that can perform many different types of operations as needed by each individual programs. It is not optimized for any specific type of computing. A GPU, in the other hand, is optimized for the calculations required for rendering graphics. It takes significantly more time in a CPU to render the same thing than in a GPU, but a GPU will be slower at many other operations. A GPU is essentially partway between a CPU, and an [Application Specific Integrated Circuit]( URL_0 )",
"Because the tasks required of a CPU and a GPU are vastly different. It pays to specialize. A GPU is many times faster than even the fastest GPU at the specialized purposes that we use GPUs for. There's no way we could design a CPU to compete with that -- unless of course, we sacrificed its ability to do *other* tasks efficiently. And then we've basically just designed another GPU. A reasonable mid-range desktop GPU can handle around 2 teraflops. That is, two trillion operations on floating-point numbers per second. A high-end GPU can triple that. Meanwhile, a fast CPU can hit around 250 gigaflops. Or ten percent of a mid-range GPU. And we can't just make the CPU ten times as big and ten times as fast, because if we make them larger than they currently are, we bump into all sorts of other limitations. The signal takes too long to get from one end of the chip to the other, limiting performance. The power usage, and heat produced skyrockets. And most of what the CPU does wouldn't really benefit from the added transistors. These days, what you gain from a bigger chip is mostly more cores, but most of the tasks that a CPU runs don't benefit from more cores. They certainly wouldn't get a worthwhile performance boost from getting *ten* times as many cores. The secret to GPUs is that graphics rendering can be easily split into millions and millions of very small, simple, short tasks. And these tasks don't depend on each others, so they can be executed in parallel. So the GPU is designed to be able to run hundreds of them simultaneously, on hundreds of small simple cores. These tasks only depend on a small set of specialized instructions (generally to do with arithmetic) And these tasks are not individually time critical, so where the CPU goes to great lengths to, for example, ensure that the currently running code can get data from memory as fast as possible, the GPU can just send the request to the memory controller, and then suspend the task until the response comes back. In the meantime, it's free to run another of the thousands and thousands of tasks queued up, because it doesn't have to finish any given individual task quickly, it just has to finish *all of them* as early as possible. So the GPU can make a lot of trade-offs allowing it to vastly speed up certain highly specialized tasks. Most of what the CPU does, on the other hand, is the exact opposite: at most a couple of tasks at any given time, and these tasks are long and complex, require a huge range of different types of instructions, and the CPU is always expected to finish *the current* task as quickly as possible. So it can't do as the GPU does and just put the current task away and do something else, if it's waiting for some external communication. Instead, it has to go to great lengths to make that communication as fast as possible, because *this* is the task the user is waiting for. tl;dr: CPUs and GPUs are designed to do different things. And they're both basically as big and as fast as it is possible to make them with current technology. Trying to make a CPU better at GPU-type workloads would require compromises that would make it less capable as a CPU."
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7yy4pa | How do spammers spoof a cell phone number to make scam calls? | Technology | explainlikeimfive | {
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"When you make an outbound call, the calling system gives the phone system the caller ID information. The reason this can be (legitimately) different from the actual call is for example a business that has both direct lines to each extension and a main line. An employee calling out would show up with the main line as their caller ID so that if the person calls back they get the main number (this way you’re not giving out the direct number unless you needed to). The spammers take advantage of this system to spoof a number in the caller ID. The phone company could counter this by comparing the caller ID info with a number you legitimately own, but they get a lot of money for all these spam calls and they’re not incentivized enough to change how they do things."
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7yyplu | Why do smartphones use chips that have several cores (6 to 8) clocked at low speeds (1.8 to 2.3 GHz) whereas desktops use chips that have fewer cores (2 to 6) clocked at high speeds (3GHz and up)? | Technology | explainlikeimfive | {
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"Mostly power considerations. First, keep in mind that the cores typically found in a smartphone are not equivalent to the cores found in a desktop system. They tend to be smaller and lower performance. So you can have a processor with 8 ARM cores in a smartphone that is significantly smaller than a processor in a PC with 2 x86 cores. The faster you clock a processor, the more performance you get, but you also increase the power drain. Power is of course vitally important for a cellphone, both due to battery considerations and the ability to get rid of the heat. The great thing about having a bunch of cores in a cellphone processor is that when a core isn't being used, it can have its voltage reduced or it can be shut down almost completely. And some cellphone processors use two different kinds of cores. One is very small and low power but low performance, the other is higher power/performance. So much of the time, the phone is just using the wimpy core and saving a lot of power. When it needs the performance, the \"better\" cores can be brought into play.",
"The biggest difference is heat and power use. Phones have limited battery capacity, and they're small and compact, without much airflow. Higher clock speeds pretty well universally mean more heat and power required. Desktop computers can easily accommodate heat with bigger heatsinks and fans. Power for a desktop is cheaply sourced from the wall, compared to carrying around all your power in a phone battery. Also, you can find CPUs for desktops from single core CPUs all the way up to 10 physical cores, last I looked. If you're willing to run enterprise workstation processors, you can go up to 24 cores. There's not really a fundamental difference between \"phone processor\" vs \"desktop processor\" on core count, it's just cost and expected use that determine that aspect.",
"Phones sometimes use an Octa-core - 8 cores. Inside the Octa-core is 2 quad cores, a low powered quad core for general use this allows a much longer battery life, and a high powered quad core, for games and other things that use a lot of processing power, this uses a lot more power so it isn't used all the much. The reason for 2 quad cores is so that it can switch between the high and low powered cores when needed so it does use more power then it needs to.",
"The 8 core are often 4 fast cores and 4 slow cores that are paired so you can switch between them. The fast as faster and the sower are energy efficient. In most cases they are paired. So in each par you can use one fast ore one slow Apples hexa core have 2 fast and 4 slow and all can be used at the same time. To explain the frequency you have to look at the power consumption of a integrated circuitry. The same amount of work can be done at a lower frequency with lower energy usage bit it takes a longer time to do. The reason is that the power usage depends on the square of the voltage and the higher frequency you have the higher voltage is need. So a 3 GHz core need more 1.5 time the energy compared to a 2 GHz core but is only 1.5 time faster if they are the same in all other ways. It is even the case that you can change the frequency of a core while it is running and lower the voltage. That is done on laptops so when it is not plugged in it can be clocked lower but is is more energy efficient. It is a bit more complex so if you design a chip to a max frequency of 2 GHz it can use less power then a down clocked chip that works at 3GHz Batteries are smaller on a cellphone and cooling is worse then a PC. So you use a less complex chip at a lower frequency. It is slower but more important more energy efficient for the same work. So you choose a chip that gives a good compromise between generated heat, battery usage and performance. In a desktop you not battery but is limited more by cooling so you can use a high frequency more complex core. It is simpler to use one fast core then 2 slower to desktop computers are designed with fewer cores but each one is fast. It is harder to program for high multiple core performance so most desktop programs works better with faster cores then with more cores So a desktop computer needs more energy to do the same amount of work compared to a cellphone. But is can to the same amount of work in a shorter time. So the designs are compromises between energy deficiency and maximum performance."
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7yz0to | How does software know where to appropriately hyphenate words? | When I use some word processors/notepads/web forms, they automatically predict where to hyphenate words between syllables when lines wrap around, to varying degrees of success. How do programs try to find where to insert these hyphens correctly? Do programmers somehow have to take syllable recognition into account? Are there dictionary-style databases of syllable-breaks for every word, that they cross-check like a spell-checker? Or are there some sort of if/then programming rules regarding common groups of letters? A preliminary Google search only yielded general rules of proper hyphenation for writers, but nothing about how programs attempt to automatically find syllable separation. I'm no programmer or developer so I can only guess. Thanks! | Technology | explainlikeimfive | {
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"I'm sure there's other ways of doing it but, largely, it boils down [to building a giant list of words and how they can be hyphenated]( URL_0 ). This list comes from a Python project but *they* took it from the OpenOffice/LibreOffice project, which is also used by Firefox, Chrome and OS X. *They* got the list from TeX."
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7z536z | How is an i7 processor faster than an i3 if the clock speed is almost the same? | I just upgraded my laptop from an i3 to a (used) i7. 2.3GHz i3, 2.4GHz i7. I'm up 100 MHz. For the price difference, I feel kinda cheated. I understand that a few decades ago a hundred MHz was a huge difference, but it doesn't seem like much to me now. I'm presuming there's more to the picture than simply the clock speed? | Technology | explainlikeimfive | {
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"**Short answer**: the difference is in how much your processor does in those clock cycles. **Long answer:** The amount of instructions your processor handles each second depends on two factors: * Clock speed: the speed at which the processor components switch state * Instructions per Clock cycle (IPC): the amount of instructions the processor can handle during one cycle. Clock speed has not improved that much over the last 5-10 years. A higher clock speed results in more heat, and we have hit a limit to how much we can comfortably cool. For desktops that's in between 3-4 GHz, for laptops that's even lower. Therefore lots of improvements have been made to the IPC. Mostly it comes down to parallellism: processing multiple instructions at the same time. If we compare processing instructions to doing the laundry: * Pipelining: instead of washing, drying, ironing the first load, then doing the same for the second, third, ... the second load can already start using the washing machine as soon as the first load is transfered to the dryer. * Instruction parallellism: if two loads of laundry require the same washing machine settings, we can put them together and execute in the same cycle. * Multiple processor cores: we use multiple washing machines, dryers, irons to wach multiple loads at the same time. * Multiple instruction threads per core: if a certain load does not need to be ironed, we can use the iron for another load. EDIT: * Most people seem to use the term \"IPC\" only to indicate single core performance, here I used it in the broader sense and do count multicore processors as an improvement in IPC. * Cache is indeed a factor I forgot. In laundry terms, cache is a set of racks where you can store a small amount of laundry. You can store laundry you just washed while it waits for the dryer to be free. Or if you have a load of blue shirts in the washing machine you can already prepare another load of blue shirts to follow so you don't have to switch settings.",
"Oooh a question I can answer. Ok, imagine you have some people painting a wall. They can paint thousands strokes a second because these are some really fast painters. There are two ways you can finish painting the wall quicker, either make them paint faster, or get more painters. In this analogy: * clock speed = number of strokes a second * the number of cores = number of painters Now when you get a hyperthreaded (or multithreaded) CPU, this is like giving the painters a brush in each hand. They can multitask now! It's hard to multitask though, so two painters are usually better than one painter with two brushes. *(In reality it's a little more complex than that, sometimes faster clock speeds will be better, and sometimes more cores will be better)* **EDIT:** I noticed I hadn't brought it back to the question really, but an i7 has one big benefit over an i3, the i7 has more cores. Now, the i3 might be better if the i7 is a lot lot older [for example an 8th generation i3 vs a 3rd generation i7]( URL_0 ).",
"Have you got the model numbers of both parts on you? If it's the same architecture for both, you're only going to see a very tiny boost in single threaded performance but the i7 probably has twice as many threads to throw around. Your team of CPU men hasn't gotten much stronger individually, it's just doubled in size. I went from an i5 4300M to an i7 4810MQ, the clock speed only went up from 2.6 to 2.8 but it also went from two cores and four threads to four cores and eight threads. Effectively, I've got twice the power to throw around now. It won't neccessarily make every single application faster, because not everything uses more than one core, but it'll let me do more things at once.",
"Another factor not yet mentioned here is cache. A computer uses multiple forms of short-term memory. These things cannot hold data without drawing power, but have much higher bandwidth. Which basically mean how fast data can be moved around. One of those types of memory is called cache, and is part of the actual CPU chipset. It's much faster than the system memory you have called RAM. The most used data is stored in the cache, anything that doesn't fit is put in system memory. Higher grade CPU's come with more cache. And this plays a part in the better performance.",
"The first thing to understand is that \"i3\" and \"i7\" are more about *branding* than technical specifications. Depending on year it came out & even the particular model that year, they could have different numbers of cores, different amounts of cache, different onboard graphics processors and other differences. The systems they're in can have different amounts and speeds of RAM, different types & speeds of HDD/SSD and might have different types/speeds of graphics processor (or none at all). All of these can have significant differences in performance. Year over year, the \"2.3GHz i3\" gets faster because they're constantly updating the core architecture so it can do more per clock tick. [Going from a 2000-series to a 5000-series gives you about a 20% performance boost]( URL_0 []=750 & cmp[]=2602). Then you're jumping from an i3, which is supposed to a mid/low-end chip to an i7, which is supposed to be a high-end chip. It's going to have more cores, hyperthreading and all the bells & whistles enabled.",
"ELI5 answer. Imagine you need to move a lot of boxes from one location to another. All CPU cycle speed does is measure how many runs you can do in an hour. But an I7 CPU can carry a lot more boxes than I3 CPU per run. So even though I7 and I3 run at exactly the same speed, I7 can do a lot more work than I3."
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7z5h4n | Why are DVDs encoded differently around the world (i.e. Region 1, Region 2, etc.)? | Technology | explainlikeimfive | {
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"They're not encoded differently, they're just locked to that region by the firmware on DVD players. A Region 1 DVD player is technically capable of playing a Region 2 DVD, it's just got a little software switch saying \"only play Region 1\" set inside it. It's possible to get region-free players or hack some models to ignore region codes. Why do they do this? Money. The movie business has a long & complex history of studios giving exclusive distribution rights to distributors in different parts of the world. The Japanese distributor has a contractual monopoly on movies from studio XYZ and doesn't want the Bolivian distributor trying to undercut their business, so the DVD standard included region codes. This also allows companies to sell movies much cheaper in poor markets (eg - India) than they would in rich countries (eg - United Kingdom) without having to worry about movies from India getting moved to the UK and getting sold on the grey market. This is the same reason that services like Netflix have different titles available in different countries.",
"Regional coding is (was?) a way to make sure you made all the money you could in each market, especially with staggered releases. For example, a movie might've been released on DVD in Region 1, but still actually be in theatres in other markets. Don't want people buying the DVD and then not spending money in the theatre. It's basically an artificial market control."
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7z698s | How do glucose monitors actually work? | Been using one for about two years now, really curious as to how it actually works. | Technology | explainlikeimfive | {
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"Imagine your blood is a bunch of adults with pixie sticks (the amount of glucose in your blood), and the test strips are a bunch of children (the chemicals on the test stip). When the adults give the children pixie sticks they get excited, from all the sugar (when you put your blood on the test strip the glucose reacts with the chemicals on it and generates an electrical current). There are more children wanting pixie sticks than there are adults with pixie sticks, so you can count how many excited children there are in order to figure out how many of the adults with pixie sticks there were (you can correlate the electrical current generared to the amount of glucose in the blood)."
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7z6tdj | how do radios with a scanning option know the difference between static and a station that comes in? | Technology | explainlikeimfive | {
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"Radio signals are electromagnetic and a radio works by receiving this energy from the air using an antenna, filtering to a desired frequency and then amplifying the audio. There will be more energy picked up when the radio is tuned to a frequency with an active broadcast signal vs when it's tuned to white noise. This means the signal level can be measured on each channel and the radio can be made to stop scanning when the signal level is high enough.",
"URL_0 basically when the input signal is mixed with the signal from the local oscillator you get out the original signal at a specific frequency range. If you detect that there is a signal at that range, (using a band pass filter), you have hit a channel. Things like the police anti radar detectors look for the frequency of the local oscillator."
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7z736i | How are cornflakes and breakfast cereal made into specific shapes? [e.g. Froot Loops, Cap'n Crunch, Cookie Crisp, etc.] | Technology | explainlikeimfive | {
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"Loops and other very specific shapes are made by extrusion: they are squeezed out of a shaped nozzle and then cut off. So Froot Loops come out as a hollow tube that is then sliced. Flat-bottomed shapes are made by depositing from a nozzle onto a baking sheet or conveyor belt. Random flakes are made by crushing between two high-speed rollers."
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7z83e6 | e-ink technology | How does e-ink technology works? I know the story that e-readers don't tire my eyes like smartphones do. But why should buy e-reader instead of reading on my phone? | Technology | explainlikeimfive | {
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"I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Kindle E-ink technology ]( URL_5 ) ^(_8 comments_) 1. [ELI5: What exactly is \"E-ink\" and how does it differ from a normal screen? ]( URL_3 ) ^(_8 comments_) 1. [ELI5: So how exactly does e-ink work? ]( URL_0 ) ^(_3 comments_) 1. [How does e-ink work? ]( URL_1 ) ^(_51 comments_) 1. [ELI5: Why eInk screens and devices aren't more prevalent? Why are they so expensive? ]( URL_4 ) ^(_1 comment_) 1. [ELI5: How come a kindle screen refreshes so slow and only in black and white, but pebble times are relatively quick and in color. ]( URL_2 ) ^(_5 comments_) 1. [ELI5: How does E Ink work? ]( URL_6 ) ^(_2 comments_)"
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7z8ijh | Why do pictures of a computer screen look much different than real life? | Technology | explainlikeimfive | {
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"Your brain does an enormous amount of image processing what your eyes take in and shows the results as what you \"see\" (optical illusions are often designed to expose this image processing). The camera takes millions of tiny samples of what's actually there at one given instant in time. Most of the time these are close enough, but computer screens use some tricks in the image processing to display an image, so the camera can't show that. The big two are: * the screen is made up of one of three very tiny red, green or blue color spots, that end up being similar in size to the red, green, or blue samplers in the camera. That creates [moire]( URL_0 ). * Further, older screens updated via a line, so the camera only captured the parts of the screen lit by the line, while your brain remembers the prior image and smooths between the two.",
"Other people have given good explanations for a lot of the reasons so I won't repeat them, but another major difference is dynamic range. This is the ratio of the brightest to darkest shades. To put it in practical terms, if you are in a park on a sunny day, you could see the bright blue sky and at the same time see a bench in the shadow of a tree. If you took a picture of that same scene, you would have to choose which one would be properly exposed in the photo. If you wanted to get the bright blue sky, the shadow would be totally black and you wouldn't be able to see the bench. If you wanted to get the bench in the shadow, the sky would be totally white. Cameras are actually getting pretty good at capturing wide dynamic range, but screens are still far behind, only being able to display a pretty small dynamic range. Even when you compensate for this with HDR (High Dynamic Range) photo processing, it still doesn't look like reality because it is only an approximation. The highlights are darker than they should be and the shadows are lighter.",
"It depends on what picture you're talking about. If you're talking about taking a photo of a screen that is on, it's because to display things, computer screens are constantly emitting lights in pulses that are fast enough to be undetectable by our brains (60 refresh cycles per second is common); and this doesn't happen all at once; Some areas light up at different times than others, depending on what technology is used to drive those lights, so when you take a picture (which has an exposure time that allows just a single frame or two to get captured) it will get the light right at that moment, more or less. In most places that you will see screens being used in movies or whatever, the actors will just be looking at a blank screen and content will be added in post-production, or special camera settings will be used to capture the screen in the best possible way.",
"Dear judah__t, I literally watched a YouTube video yesterday that thoroughly explained this subject. [Here it is my curious friend]( URL_0 ) Enjoy, -me",
"Cameras “detect” the refresh of the scree. That’s why you’ll generally see lines and/or pixelation occurring. Your vision doesn’t see these things b/c it’s not a snapshot of the screen like a photo is.",
"*When a grid's misaligned,* *With another from behind,* *That's a moiré* *When the spacing is tight,* *And the difference is slight,* *That's a moiré* Credit: Randall Munroe",
"Theres a video of a guy recording his own video so many times and he's explaining how the pixels get downgraded each time he uploads it again. And again. And again... Ill look for it now.",
"the simple answer is that the camera shutter is much faster than your brain's ability to process images. When a camera takes a picture that's the information capture during the few instants the shutter is open. Then depending on lens curvature, sensor (or film) light sensitivity, white balance, etc., you will see the image representation of what was on the screen at that time. You brain never stops processing images and your eyes can't focus on the whole screen at once. So you end up with an interpreted version of reality.",
"Not sure what your question is precisely or if I understand you correctly. Most photos taken are in such perspectives and depth of fields which are way different than human eyes. Simply put, the optics of a camera system that produced the photo you see is different than your eyes and retina. So for the same object/scenery, the reproduction from a camera is different than that from your vision system. Also factoring shooting technique and post-processing. An extreme case is long exposure, your brain simply cannot put up 30s of a scene into one image while a camera can. The way highlight and shadows being processed by camera and software is totally different than the way you brain does it too.",
"Because \"real life\" constists of millions of billions of billions of atoms that all can have different colors and bend, scatter, block light in a myriad of different ways, and they do that pretty much nonstop at an \"infinite\" framerate. Whereas a good TV is in the order of a mere 10 million pixels that have only a very limited range of colors, and can do at most 120 pictures per second.",
"Because people on dating sites only post the flattering pictures of themselves. You know, the ones from 10 years ago before they got fat, wrinkly, and grey? On the computer they look hot, in real life, they look like the grandma of someone hot.",
"I don't know what you're talking about. Example pls?",
"Basically the screen refreshes at a rate faster than the human eye can perceive, but if you take a still image, or video, the camera picks up on it.",
"Since the question has already been answered, ill just supply a fun note: if you point a remote into a camera you can see the light when you press a button on the camera screen. Small sliver of the population doesnt know this.",
"Two reasons most people don't usually realise: One, a camera lens is curved just a little bit differently than the ones in your eyes. So a picture is just a little bit different than what you'd otherwise see. Two, color is very hard to stay accurate when you translate it from computer screen to camera sensor, and then back to a new display. Some colors will almost certainly change in the process.",
"Because of the refresh rate. The screen will \"flick\" very very fast in real life, just like any kind of movie shown on any screen or projector. That's what creates motion illusion, I'm sure you heard about it before. When you take a picture, the camera shutter is really really fast, and it can't synchronize with the refresh rate of the screen, which can vary. Pictures of old tube TV's and monitors show this effect really well, as they refresh in lines, from top to bottom. This video explain far better than me: URL_0",
"Lot's of really good answers, but they're not really ELI5. Here's my try: Computer screens use tricks to make a fake picture that looks to people like a real picture. Cameras use a different set of tricks to save a real-life image, so that it can be looked at later. But the computer screen's tricks aren't compatible with the camera's tricks. Essentially, a computer screen's tricks will *only* fool a human being (and some kinds of animals like dogs), but it will not fool the camera. When you look at the picture the camera took, you see what the *camera* saw - *not* what a person would see if he was standing where the camera was. Of course, some types of screens will look better on camera than others, and some types of cameras will work better with screens."
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7zboc9 | How do you know that the amount of gasoline displayed by the pump is actually the amount you are receiving and you’re not getting ripped off? | Technology | explainlikeimfive | {
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"it is heavily regulated and tested, you'll see a sticker talking about weights and measures certification. Its tested regularly, and if it were tampered with, they would face steep fines.",
"How do you know for sure? You don't. But you can be reasonably confident for 2 reasons: 1. Pumps are periodically tested. The testing agency puts a sticker on the pump that shows when they checked. 2. Most people wait until their tank is mostly empty before they fill up. You know how many gallons your tank will hold, so if the pump charges you for more than your tank will hold, you know you are getting ripped off.",
"Check the pump for a recent inspection sticker. They are pretty tightly regulated and required to be tested once in a while. That said, it's actually fairly common for the numbers to be off significantly. Sometimes this is intentional, sometimes not. If you think you're being shortchanged, you can complain to whatever department is in charge of your state's weight and measures. If you check the sticker at the pump, you'll probably find the number to call.",
"Most state's Weights & Measures department regularly inspect pumps for accuracy as well as inspecting safety of the pump and fuel standards. URL_0 Most states have a number that you can call if you are concerned about the accuracy of the pump."
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7zcer3 | Why do some cellphone front cameras take 'mirrored' photos? | Technology | explainlikeimfive | {
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"This is controllable in software. Some manufacturers want it to take a mirrored picture so that users don't get confused when looking at themselves -- users *expect* the phone to work like a handheld mirror.",
"All conventional cameras [[and eyes]( URL_0 )] produce upside down images, so everything's being corrected one way or another. So the choice of how to orient the image on a software camera is entirely a matter of usability. When the output of a front-facing camera [or webcam] is shown on the screen right beneath it, the end result is pretty much a mirror, & people interact with it like a mirror. If the phone doesn't mirror the image on-screen, it doesn't match people's expectations, so it's be more difficult to position things in the frame. iPhones, among others, flip the viewfinder but not the saved images. This removes the main downside of flipping the image [reversed text]. And even if the saved image is reversed, it's easy to flip it again afterwards, so simplifying the capturing process generally takes priority."
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7zcllx | What is the process of laying underwater fiber optic cables in the ocean? | Technology | explainlikeimfive | {
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"They plan the route it's going to take, roughly where they're going to run the cable, but the process of putting it down there is literally unrolling it off of a cable ship, and letting it sink. They just set it down, basically."
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7ziny4 | Why do modern Game Consoles (i.e: Xbox One) seem to have less games than their predecessors (i.e: Xbox 360) despite having the same game companies? | You often see people comparing their piles of games. One pile has Dozens of games for the Xbox 360, whereas their Xbox One pile is hardly 5 Games tall. Is there a reason you seem to see more games for older consoles, despite newer ones having the same successful companies producing games, as well as Indie games? | Technology | explainlikeimfive | {
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"If you look at big publishers, they're moving their focus to making money via their new term \"live services\" (so to them, you'd ideally play destiny 2 for 10 years, constantly giving them money through their own currency). EA made $4 Billion last year just from \"live services\" eclipsing what they make from game sales. Maybe it's a fad, but it does give independent games an \"in\" for people who don't like that model (assuming they don't also follow the same model, as it's a money factory).",
"Development time for games has risen in step with greater processing power for consoles. You didn't need much in the way of artistic skill to make a nintendo game; you only had 8 pixels to work with. Even a PS1 game could be done with cell shading or some huge polygons. But for a AAA PS4 game? Players expect movie-quality graphics, because the machine can support it. This requires developers to put insane budgets into each title, and squeezes our smaller developers.",
"The old system has had time to rack up a ton of games, the 360 was released in 2005. Give it time, account for the cloud and It'll even out",
"Maybe it has to do with the fact that you have to install games on newer consoles. You can’t just pop in the disc and play right away. And since I have to put the disc in every time I play it now, despite having the game installed, I now buy only digital games. I can uninstall them if I need space and they’re in the “cloud”. This is my personal opinion."
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7zj4hy | Nashville Mayor’s affair proven by reading deleted chat logs from her cell phone. How are these deleted files accessed? Are there ways one can securely delete private data from cell phones and computers? | [Here’s]( URL_0 ) the article that brought this to my attention. It seems like in this day and age, many people likely have private conversations, pictures, etc on phones and computers. Should there just not be an expectation of privacy ever? How is it deleted files can be recovered? Are there ways to actually ensure privacy on digital devices? | Technology | explainlikeimfive | {
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"Most computer file systems operate like the planning department of a city rather than a demolition firm. When a file is deleted, they mark the space as available and ignore the existing data, which will be overwritten if/when a new file wants to use the space. Until a new file actually uses the space, the old data is available to be recovered. There's software for many file systems that can automate the recovery process. Computers have always been terrible for privacy, without lots of very careful precautions (strong encrypting at the file system level and and strong encrypted for communications, as well as other operational security good practices). The privacy rule for computers has been \"never put anything on a computer that you wouldn't put on a post card\" for several decades. That lots of people don't follow this rule, without having their affairs revealed is more a factor of the lack of interest in them rather than any inherent security. It's quite hard to secure a smartphone, because your phone is designed to share as much as possible, because the phone makers all want to use your information to more effectively sell you things.",
"So when you delete a file off of most computers, the computer doesn't actually *do* anything to that data, other than hide it from the view of the operating system, and mark that section of your storage device as OK to re-use. The right software can just get the data off of those sections of storage media. There are tools that can be used to \"zero out\" a hard drive (so called because it takes every bit (1 or 0) and sets it to zero) or a file, google with keywords privacy and true delete and you'll find dozens of software packages that will do things like this. But there are forensic methods that can detect what data existed even before this is done; your run-of-the-mill phone snoop won't likely bother with this, but law enforcement can get things off of devices that have been melted to slag. When you're under investigation for a crime, and law enforcement is searching your stuff, then there's not really an expectation of privacy."
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7zjn19 | Why can't emulated GameCube games, for example, be pre-translated for the computer? | Okay, so I know that the reason emulators are slow is because they have to translate the target code into something the computer knows how to work with. However, wouldn't it be faster to emulate the game if a program had pre-translated the console/game code into the desired code for the computer? That way, there's no real time translating going on inside the emulator; it's just reading the game code as the computer would. Is this possible? What are some of the limitations to doing this? | Technology | explainlikeimfive | {
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"Emulation generally doesn't run slow because of issues with translating the code, but rather the fact that the code is optimized for hardware that your computer doesn't have. Think of it like this. I have two calculators. One of them can do addition really well, it can do any addition problem in 1 second. This also means it can do multiplication by turning things like 3x5 into 3+3+3+3+3=15, though that means it takes 5 seconds to do that problem. This is your computer. I have another calculator that isn't near as fast as the first one, it takes it *3 whole seconds* to do any addition problems. But this calculator has a special \"multiplication circuit\" on it that lets it do multiplication problems directly in only 2 seconds! So it doesn't need to break down 3x5 into addition, it can just chug for 2 seconds and then say \"=15\". This is the console being emulated. I give both of these calculators a sheet of multiplication problems (a video game); which one finishes first? Of course you would answer the second one, because every time the first one needs to do a problem it needs to break it down into addition steps. This is why emulation is slow and why you can't \"pretranslate\" a game in the method you are thinking of (the closest would be to prewrite the problems as addition instead of multiplication, which is what an official port of the game would be). Of course this doesn't mean emulations *can't* run fast or faster than the original. What if my first calculator was so good it only took .01 seconds to do an addition problem? Then even if it had to break every single multiplication problem up it would still probably be faster than the calculator with the special circuit that took 2 seconds to do a multiplication problem. This is what happens when you emulate older, smaller hardware like a game boy on modern computers and why it's more feasible; you basically are just overpowering the problem rather than actually making it easier. Newer consoles are much closer to normal computers in power, however, and that is the reason why emulating them well either runs much slower or requires a much more powerful PC."
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7zkxs5 | why does the iPhone 7’s home button become unclickable when the phone dies? You can click it when it’s on, but not when it’s dead | I’ve always wondered why my phone did this. | Technology | explainlikeimfive | {
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"It's not really a button, it's simply a sensor that triggers a small vibration when it's feels you pressing it. When there isn't any power the sensor and the vibration don't work so it's just a piece of glass (sapphire?) at that point.",
"because its not a physical button, its a clever software and hardware combination of the haptic engine which apple does very very well. The \"click\" you feel is a single cycle of the haptic engine, essentially the thing that drives the phones vibration. No power means no power to the haptic engine.",
"It's not a physical button It is a force sensitive circle but doesn't move up and down like a button. When you push on it the phone buzzes slightly to give you the sensation of clicking the button. The sensation of pushing the button and the fake click are close enough together that your brain assumes the button clicked and interprets the buzz like that It's called haptic feedback and it's the same reason keys on your fully digital keyboard can click too"
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7zn9gn | Why do Americans have a different keyboard layout than Europeans even though they need the same keys? | Technology | explainlikeimfive | {
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"The QWERTY layout was devised for mechanical typewriters. They used mechanical levers and \"hammers\", which flew up and physically hit an inked ribbon pressed against the paper. Sometimes these hammers got jammed and tangled up, but it was eventually realized that careful ordering of the hammers would make that less likely. And because these hammers had to be connected to the keys physically, by means of levers, that meant re-ordering the keys on the keyboard. Hammers with letters that were used frequently together could be spaced so that they wouldn't get tangled. And so the T and G -- which in English are almost never used together -- were next to each other, but both a little further away from H (because TH and GH are frequent letter combinations in English). Remember, I am talking about the hammers, not the keys: on the keyboard, it so happens that all three letters are quite close to each other. But different languages use different letter combinations. For example, in German, Y is used much less often than it is in English, and Z is used much more often, and so you'll find that on a German keyboard, Z and Y are swapped (so Germans use a QWERTZ layout). Not only that, but languages sometimes have letters that don't even exist in English. A German keyboard has to find room for Ä, Ö, Ü and ß, for example. On an English-language layout, those keys are used for punctuation marks, so a German keyboard has to put those punctuation marks elsewhere. And different languages use different punctuation marks. Until the invention of e-mail, the symbol @ was only used in English (it meant \"at\" when talking about prices, so \"4 items @ $10\" meant \"four items at ten dollars each\"), so German keyboards never used to have it. (Now they do, but it's a bit tricky: on a German computer keyboard, the right Alt key is replaced by a key labelled \"AltGr\" -- as it is on the US International layout -- and to get the @ sign you have to press AltGr+Q.)",
"Because they don't need the same keys. Most European languages have extra characters that are used frequently and don't exist in English language (i.e. German äüö). These keys have prominent places on the keyboard where the American keyboard has special chars like curly braces."
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7znmi4 | open source: why are so many people willing to write software to give for free? Also, why is it in similar areas, eg game dev or digital media design, open source is much less common? | Technology | explainlikeimfive | {
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"Reasons to develop open source: 1) Because other people can use it and therefore it is useful for human progress. 2) Because people can then customize it for their own use, and look through the source code to ensure that they are not being spied on by inbuilt spyware or nagware 3) To practice and showcase their skill and prove that they can code 4) Because they like the fun of solving a puzzle rather than developing software for some goddamn clueless manager who doesn't know or give a shit about it. Reasons not to develop open source: 1) Because you gotta get paid somehow"
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7zpijx | Can anyone in IT break down the difference between a Database, Data Warehouse, Data Lake, Data Mart? | I'm trying to understand the flow of enterprise data and how it's stored, captured, then used for analytics. I'm trying to get a foundational understanding of some of the vocabulary so I'm not completely lost. | Technology | explainlikeimfive | {
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"Database - This is a general term and the other 3 are just types of databases that are structured differently. But it may be that those you are talking with are applying this to be the main user application. Data Warehouse - Is a database that has been designed specifically to hold data in a form that makes it easy to create reports from and it structured to perform that task quickly and efficiently. It often contains data from across different areas of an organisation, so report the number of widgets made from the manufacturing system beside the sickness/absence rate of the people in manufacturing. Data Mart - This is usually a subset of data within a data warehouse for a specific area. Data Lake - Trendy name for a huge data warehouse but probably just for a specific subject area",
"There's a lot of wiggle room in all these terms, and different companies/industries will use them slightly differently, but here goes: * *Database* An information store about a single area of the business. The Sales database will have all our current and prospective customers, what they bought and for how much, etc. The Supply Chain database will have where all our widgets are, how many widgets we build per day, and what we are shipping out. * *Data Warehouse* A big information store that holds a copy of all or most of a business's individual databases. A team of data people will create new tables and reports that link information from multiple databases. This give you the ability to ask broader questions like \"How many widgets will we ship today to our biggest customer\". * *Data Lake* Like a Data Warehouse, but the focus is more about bringing in every possible piece of data that a company has into one place. There may or may not still be a team of data people creating new tables on top of this. Sometimes implies that you're mostly on your own to find/link the data you want. * *Data Mart* Like a Data Warehouse, but focus is on easy to use/easy to access tables from the team of data people. Usually has a web page where you can go and see what's available and download it. Sometimes implies that the original source databases are mostly hidden in favor of organized sets of data.",
"Transactional databases are a single ledger that tell you about one particular topic, marts and warehouses are encyclopedias that can offer unique insights and are often designed by bringing together data from several transactional systems. Data lakes are an uncategorized collection of reports, encyclopedias, and other random files designed to store as much data as cheaply as possible. Databases are programs designed to store and catalog data. Databases come in different shapes and sizes depending on the specific way they will be used and the volume of data they process. There are two main types of databases OLTP and OLAP. An OLTP (online transactional processing) database is what most people think of when the word database comes to mind. It is used to store transactional data from stores, websites, etc and is designed so the data from individual or small batches of records can be quickly retrieved and reported on. Think about a collection of transactions from the business day, it allows you to record the overall sales for the day but doesn't tell you much about the health of the company or any potential future sales opportunities. Data warehouses and marts on the other hand fall into the OLAP category (online analytical processing) they are designed with historical data in mind and are often used to gain insight into company health/ potential opportunities. The difference between the two is the development strategy. There's a lot behind that so for those interested look up the Inmon and Kimball debate. These are the types of data sources that AI might use to gather Intel on potential clients. A data lake is a collection of data, some things in databases some things just stored in file servers. The goal is cheap storage of large quantities of data. Source: I recently completed an M.S. in data analytics"
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7zpo4e | Why can't files (documents, pictures, presentations etc.) open in some program be moved to a new folder while they're open? | If I remember correctly, which I may not, this is true of Windows and Mac. I can't speak for the other OS's, but I assume there's something intrinsic to how they're designed that makes it this way. | Technology | explainlikeimfive | {
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"It's to maintain version control. Let's say there are 3 people in my department at work who are required to keep a specific file updated. I start making changes at 12:05, but I haven't saved the file. The person next to me makes changes at 12:06 and then saves the file. I then save the file I have open. Well, all the changes the person next to me made are now gone because I've saved the file with the version I was working on. The easiest way to do this is to lock files. Granted, this isn't a great system because this situation would be better handled with a database, and not something like an excel file. A database records transactions (changes) as they happen in order. That said file locking is important for all operating systems so that important OS files that are in use aren't changed while in use, or the machine would crash."
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7zttct | Who decided that the standards were 4:3 16:9 21:9 for aspect ratio? | Technology | explainlikeimfive | {
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"It's because 4:3 is closest to our vision and is best to relay information, 21:9 was already the standard of cinema and is best to describe scenery. 16:9 is just the compromise between those two. And for where those numbers came from, there's only 1 word: compromise. The artist, engineers, and the market all fought with eachother with their own aspect ratios. Those that survive are the ones we use today. Example: there now exist mobile phones with 17:9 and 18:9 resolutions, due to how applications are layed out on the screen (vertical scrolling). Only time can tell if they survive and become the new standards."
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7zv6hk | What is a "print server" | Looked everywhere for an understandable explanation, still can't understand what a print server is and what the difference is between "regular printing" and using a print server. | Technology | explainlikeimfive | {
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"A print server is a computer (often embedded in a networked printer) that handles print requests from multiple clients on the same network. This lets multiple people use the printer over the network, with the print server caching print requests and handing them off to the printer in the appropriate order (potentially change the order of print requests based on priority)."
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7zvlpt | How do game designers create the logic or on what do they base the logic in sport video games to the deliver the correct commentary in the corresponding situation, e.g. football (soccer)? | Technology | explainlikeimfive | {
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"My partner is a game dev so from what I've learnt from him: The dev will create a sequence of scenarios and imput them as codes with a yes or no answer to branch off from. for example in a soccer game I would assume it would be something along the lines of; does ball reach goal? If yes trigger audio 1. If no trigger audio 2."
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7zw61t | What is the order of shutting down a computer/laptop? Which hardware pieces are shut down first, and last? | Technology | explainlikeimfive | {
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"The purpose of a proper shutdown is to save data in applications and services to disk to prevent data corruption and data loss. As well as to cleanup logs and temporary data. This way digital garbage data (left-overs from a running application) isn't left lying about on your computer taking up space or potentially causing issues during a bootup or application start. 1. Applications are shutdown, logged in users are warned to save data in applications that are still running. Programs are then forcefully closed after a timeout. 2. Users are logged out, sessions are terminated, disables the GUI interface to prevent any application launches 3. Services (applications that run in the background) are stopped. Drivers are unmounted. Hard drives and other devices with moving parts are stopped. Data in caches is written to disk to prevent data loss. 4. Computer sends termination signal to the hardware, turning the power into standby mode (off)",
"apart from a few things, there isnt a set order as far as i can tell. once user software and system services have saved their work and ended their processes, the I/O manager sends a shutdown signal to every driver. these send back any configuration changes and other data that needs to be saved and confirm they're ready. then the manager can end the driver processes (which depending on the hardware attached, makes it stop drawing power. that's why your mouse stops glowing before the PC is fully off), make sure the data is written to disk, and finally cut power to complete the shutdown"
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7zwkft | In programming, what is the difference between shitty and beautiful code? | Technology | explainlikeimfive | {
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"The difference comes 6 months down the road when you have to come back and add to it. Shitty code is when you come back and go “wtf is this crap” and beautiful code is “wow this crap is decent”.",
"Beautiful code: - Clear and easy to understand - Nicely formatted - Nicely and correctly commented - Maintainable Obviously these may be subjective, but there are some things most people agree on when it comes to each of these points."
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7zxnrb | How could old tvs (and Home appliances in general) be fixed with just a hit? Why this doesn't work anymore? | Technology | explainlikeimfive | {
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"Home appliances used to have a lot of \"discrete\", i.e. separate and relatively large, components. Lots of problems were due to loose connections and other similar mechanical issues. By hitting the TV/home appliance, you could (with some luck) reconnect the components and fix it. Nowadays, home appliances are smaller (think OLEDs vs cathod ray tubes). Because the components are so small (and often \"integrated\" in few chips), it's unlikely that you can fix a TV by hitting it.",
"This is called \"Percussive Maintenance\" and works particularly well with vacuum tube based electronics. Hitting the device on the top and sides would either knock the offending tube back into place or knock it out so its easy to find With some more modern electric devices it can knock crap off the board which may be providing an alternate path or knock a loose connector back into contact. For devices with motors or other moving parts(even relays) it can unstick them and once they're moving they're fine",
"It does still work sometimes. It is because there is an intermittent connection and the whack makes it work temporarily. In the repair business it is called percussive maintenance. Newer TVs and appliances often have fewer connections because the electronics are mostly on a single circuit board."
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8014ys | How do people hack (cheat) in video games, and how can hacks be prevented? Why are so few games completely cheater-free? | Technology | explainlikeimfive | {
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"Hacks basically look at the code of the game and alter values or processes to achieve a beneficial effect for the player. This can be done in a number of ways, including altering what the game is doing while it's running, or changing the game prior to running it. Hacks are typically tracked and detected by comparing what the game *is* doing against what it *should* be doing, or against what the files *are* to what they *should* be. If you check the files and they're different, it might be indicative of tampering. Similarly if a player is doing something faster/better/stronger than your original parameters permit, it could be tampering. Unfortunately this does mean that practically any game where hackers can get access to the code/process of the game in even fairly simple ways... they can modify it. The protections listed above are also rather intensive and not always reliable. You either don't catch everyone or you catch innocent people as well. It's a very delicate and difficult process. The other approach that has a bit more longevity is having a closed system. Consoles tend to have a grace period where hackers cannot access enough resources of the game to alter anything meaningful. This is mostly a ticking time bomb though until things get cracked open... at which point, the same all applies and it's a game of cat and mouse between the developer and the cheats."
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801tci | what's the purpose of electronically signing on a credit purchase especially when most signatures are not the person's actual signature or lazy scribble that doesn't resemble letters and In what ways are they used? | Technology | explainlikeimfive | {
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"There is zero security in a signature. No one checks them, and only a very few are able to detect what is a genuine signature and what isn't. The best they can do is provide evidence if the holder of a card who did a transaction tries to charge it back. Then the recording of the signature can be verified by real experts, or, more importantly, video of them signing for the transaction produced in court to support a fraud charge. Similarly, the record of a fraudulent signature will be an extra fraud charge if they catch someone who uses someone else's card.",
"I know signature originally were used as a personal stamp on any document giving your approval, authorization, or commitment and use as proof if any legal things came up. But now, how would they prove anything or use it against you when most electronic signature are no where near the same or legible?",
"For card transactions, the signature was intended to play 3 roles: So the clerk could compare the sig on the receipt to the sig on the back of card, to hold the consumer responsible as in a contract sig, and so the card issuer could hold the seller responsible for misuse. The first 2 purposes long ago lost their utility as sellers overwhelmingly elected to ignore the fraud prevention purpose in favor of speed at checkout. They still collected sigs as protection from mass disputes of their transactions, but they basically chose to eat the occasional fraud that maaayyybeee could have been avoided by comparing sigs on card and receipt. (In the US, Ace Hardware is one place that, in my experience, has continued to train clerks to verify sigs. They ask to see the card and compare sigs. They make me sign the back of the card and show ID if it is not signed. This slows down the checkout process, but tells you Ace is a stickler for rules.) Over the past 10-20 years, most card networks removed sig requirements for low-end sales, such as under $25 or under $50, for certain industries at least. Issuers kept sig rules around longer than practical because they pushed a small amount of the fraud expenses on to sellers. Sellers don't have enough incentives to prevent fraud as it is; they are just eager to make a sale. And clerks just want to move the line and make it to their next break with their sanity in place. :-) Recently, however, Mastercard announced in Oct 2017 that it is eliminating sig at checkout rules as of April 2018 in the US. Discover and Amex followed suit, and Visa more cautiously announced no sig only for chip-based transactions. So in the US, consumers may soon see far fewer sig requirements, although some sellers may keep them as the receipt may be considered an agreement between the consumer and seller. In Europe and some other regions, Chip and PIN is prevalent and provides better security. Source: Work in the payments business. Tldr: Sig at checkout is going the way of copy paper and \"knucklebusters;\" into granpa's tales of how hard life was when he was a kid. Edits: wording and spelling.",
"I think the main reason is fraud purposes. Someone used my moms credit card info, and while she never really signed her name at all the thief did. The fraud people pulled her record and saw a bunch of houses and suns and stuff instead of a signature and gave her money back.",
"My family went to sign in to go indoor skydiving, and they made us sign waivers. On a tablet. Problem was that the refresh rate on the pen they used was so low that any normal signature was turned into a scribble.",
"Every other country on Earth uses a chip and pin system, much like metric the US refuses to play along. I have read at least two articles every single year, from various news sources, stating that chip and pin are coming to the US soon, for the past five years or so, maybe longer. They always go on about how the credit card companies want to reduce fraud and a pin would be more secure than the completely useless signature. I thought it was finally coming when every credit card company seemed to roll out chips in their cards recently, but alas, no pins yet and checkout often still demands a signature. They are super pointless, even the companies themselves admit it, and yet it endures forever literally no reason other than inertia.",
"My signature on my drivers license is so bad that i can hardly recognize it. Screwed me Over when i was taking the MCAT (med school entrance exam)... everytime i entered or left the room for a break i had to sign a form with a signature matching my drivers license. Since my sig was so abnormal they wouldnt let me sign out or in until i was able to replicate the bad signature. Took a few tries before i could."
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803i65 | How are commercials added to TV broadcast? | Just like title says. Are they added by networks? Then how are they of local businesses? Is there a guy on the other end with after effects on a PC constantly rendering the videos? What's the process like and on what equipment? | Technology | explainlikeimfive | {
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"It's like a playlist. There are some gaps in the playlist of a specific duration. These gaps are filled by different local broadcasters by relevant ads.",
"I worked for a small town TV station in the early 2000s. Technology has improved and changed a lot and also it was poor but here's how we did it. There are TV networks like ABC, NBC, Fox that are national networks, but they have local TV stations affiliated with them like KOMO 4 News etc. It might be ABC World News or something and every affiliate is playing it. At the end we'll do a countdown and switch the broadcast from the external source (sent by the network) to our studio. For the commercials I would cue up tapes with all the commercials on them,throw them into a tape deck and then we'd countdown, I'd hit play and they would switch the live broadcast over to the tape deck. After Effects used in post production and making graphics and animations but not in live broadcast. Broadcast is actually edited live on the fly, using a switcher board. When watching live there are people manually starting and stopping the commercials and controlling a feed that can show what a camera is seeing at the particular moment, over to pre recorded tapes, over to graphics that an animator put together minutes earlier."
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803rsi | How does Vsync prevent screen tearing? | Technology | explainlikeimfive | {
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"text": [
"Screen tearing happens when your video card starts drawing a new frame while you're in the middle of refreshing the screen. Vsync forces the image on the screen to only refresh in sync with a new screen."
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8047tz | How are toilet paper rolls sterilized? | On the packaging for my toilet paper, it says “sterilized under high temperatures”. How does it work and wouldn't it burn under high temperatures? | Technology | explainlikeimfive | {
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"TP rolls are not sterile. We do heat the paper to extreme temps while being made on the paper machine but they are sometimes not converted for a few days. Once it goes through the converting process it is cased and send to the warehouse. It can sometimes be there for a week before it’s sent to the store for purchase. You can see there are multiple ways that contamination can happen. However. I can tell you that in my particular mill it is kept VERY clean. Housekeeping, safety, and quality are the top priorities. If all machines run correctly and we have no stoppages the paper should go from pulp to case to consumer without ever being touched by human hands. Source: work at TP factory - 15 years",
"Modern paper manufacturing processes use heated rollers (filled with steam) to quickly dry paper and keep the assembly line moving. The sterilization is an unintended byproduct of this process that they're passing off as a selling point; it's basically equivalent to putting a \"Gluten Free!\" sticker on a steak. As for how the paper doesn't burn, it's simple. Paper catches fire at ~420-475 degrees fahrenheit (depending on the kind of paper), and water boils at 212 degrees fahrenheit, leaving you a 208-degree safe zone where water will boil but paper won't burn. Just sterilizing takes even less heat; 161 degrees for 15 seconds will do it.",
"Is like to add onto your question. Ive never seen tp rolls say they are sterilized but wouldn’t they become in-sterilized once you took them out of the wrapper and hung it in the wall? It’s sitting next to a flushing toilet so there’s no way it can keep sterile right?",
"Bacteria that have negative effects from humans can't digest the cellulose in wood products. There is nothing for them to live on in a roll of toilet paper. A mold or fungus on the other hand..."
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805l7q | How accurate are cigarette smoking simulators? | I just watched (another) one of those tests where they "smoke" 30 packs of cigarettes through a pressurized machine and then show the tar lined hoses and nicotine stained housings. How accurate are these? I smoked for 21 years and quit 6 months ago. I've been a runner for 15 yrs. I'm moderately athletic. Smoking took a tole on me, I'm not claiming otherwise, but I feel like those tests are highly misleading. I've never coughed up tar. In the test the hose was dripping with black oil. The filters in the vacuum were completely yellow and oily. I can't see my lungs but I feel good. I still run/hike long distances. I seem to have more stamina than most of my non smoking friends. It might be conditioning. It might be that smoking isn't as bad as they make it out to be. It might be something else. I would love to hear your knowledge! Thanks! | Technology | explainlikeimfive | {
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"Just do a Google image search for smokers lungs. They are black. Lungs shouldn't be black. Your body may have adapted well to the fact that your lungs are damaged, but they are still damaged.",
"I think the big thing those tests don't show is that your lungs (and the human body in general) is constantly repairing itself. Over the course of 30 packs your lungs won't necessarily look like the tests, even though the total amount of tar and other things from the cigarettes is accurate. Still quite bad for you of course, but I'm not a huge fan of scare tactics like that to \"convince the kids\" to not smoke/do drugs. They're always so over sensationalized it's off putting and hard to take seriously.",
"Very. I'm currently trying to quite and the thing that got me to start trying was when one of my friends put a clear mouthpiece on my filter and told me to smoke it. I did and you could see the tar build up after 1 cigarette. It was disgusting.",
"I’m guessing [this video]( URL_0 ) is that you’re referring to. No question smoking tars up your lungs, but this is an unrealistic exaggeration. First, most people don’t chain smoke 30 packs with a single breath/cig. So your total intake would be less (smoke off the tip) and you wouldn’t have a consistent ember vaporizing the leaves just ahead which add more aromatics/oils to the smoke stream. Second, you’re lungs aren’t filters. The surface area of your lungs are waaaay less than that of the cotton balls. A better setup would just line the glass inside with a cotton sheet and take short puffs. Finally, your body does work pretty hard to remove the tar and such between cigarettes, so the total might be high, but the max accumulation would appear lower.",
"Bodies can react differently to certain situations. Smoking doesn’t guarantee you’re gonna get cancer or be adversely affected, it just makes it much more likely you will."
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8072e2 | Fellow Musicians, Explain Amplifier Gain, Treble, Bass, and Middle | Before I get the "JFGI" comment, let me explain. I understand quite literally how bass, treble and mid knobs will affect how the amp projects certain frequencies. What I want to know is how I can use these features to make different sounds with my bass. Also, i just don't understand gain. Thanks everybody! | Technology | explainlikeimfive | {
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"text": [
"URL_0 This is a good article on what gain is, and why its useful. In short, gain lets you adjust the shape of the sound (like distorting it) whereas the master volume controls how loud it is."
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8072n1 | how the video feeds are shared globally for events like the Olympics. Is everything mixed and edited in one place then shared or do local broadcasters receive all of the video feeds and edit themselves? Also is the data shared via satellite? | Technology | explainlikeimfive | {
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"text": [
"They are cut and edited on site by dedicated broadcast teams and then broadcast out via one or more of the following: cable networks, data networks, and satellite tv broadcasts. Cable would mostly be used only for short distances, but data connections, such as fiber optic cables, are a really good (quality, speed and cost effectiveness) choice for global transmissions. Satellite TV is good, too, but less used nowadays. Data satellites don't really do anything that the internet backbone (ie. fiber optic) won't, so whether they use satellite or cable is mostly up to the available infrastructure and costs. Data satellite usage used to cost an arm and a leg, but the prices have gone down a lot in the last 10-15 years. The throughput is still often smaller and latencies aren't really a lot better than with fiber, so fiber is usually more cost effective if a connection is available at the broadcast site.",
"The Olympics guard their copyrights zealously. That changes the dynamic of how Olympic highlight clips might be used. In broadcasting local affiliates get feeds from their respective networks of highlights of sporting events. However, in TV stations with a well staffed sports department they will usually record the broadcast events live so they can pick and choose their own highlights while the event is still under way. In that case I guess the answer is \"both\". With the Olympics TV stations are only allowed to use the selected clips that are sent to them through their respective networks. There is a \"must kill\" date of 24 hours (or 48 I can't remember) which means you can **not** use the clips after they expire and you are forbidden from archiving them to use again. No one is permitted to record the \"off-air\" broadcast of the games for re-use. Technically, other sports organizations have similar usage rules, but don't bother to enforce them as far as sports coverage is concerned. Try using those clips in a commercial or movie without permission and it will be raining lawyers on you. Typically the events are recorded on location by the broadcasting network which has the licence (NBC has a long term contract). They will put together the highlights which are then provided to the other networks for distribution. This is like a pool, where one station gets to go in with the understanding that they have to share (this is how most courtroom coverage works). Traditionally clips have been, and still are, transmitted by satellite. However, FTP distribution is quickly taking over."
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807f2v | Why would film makers choose a smaller film size like 16 mm as opposed to 35 mm or greater? | If the bigger film size allows film makers to show more detail, why would they choose to film in smaller sizes? Is it simply budgetary reasons? | Technology | explainlikeimfive | {
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"text": [
"The film and the camera are cheaper. It also creates a grainy, rough look that may suit their artistic goals of being explicitly \"movie-like.\"",
"It's cheaper. Not just the film stock. Cheaper film, cheaper cameras, cheaper lenses, cheaper processing, cheaper everything. Cameras are smaller, allowing more flexibility when shooting. There may be a certain aesthetic they're going for, like a cheap 70s horror look, or an artistic grainy look that's easier with 16."
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807puv | Why are there fake profiles on social media? | I understand scams where people reach out to you and try to get information from you, but there seems to be a lot of fake profiles that just comment on articles for no reason. They leave some standard, “That is the funniest article I’ve ever read” type of comment. It is obvious because they do it on sad articles or something that’s not funny. When you click on their profile, there are hundreds of photos taken from the internet .. flowers, the sky, etc. It doesn’t seem like they’re reaching out to people, so what exactly is gained here? | Technology | explainlikeimfive | {
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"They could be building the background of what appears to be a legitimate account by creating a history of activity. The account can later be used to promote a product/agenda/idea/etc. It could also be a company who offers users comments, likes, retweets, activity in exchange for money. They create a large number of these fake profiles and when a customer wants more followers or activity this large network starts posting random stuff because the time it would take to make actual relevant comments is too large for the general market demand.",
"Usually they want to create what looks like real accounts so that they can be sold to people who want to promote a product/ideology/whatever. It's easy to tell that a product recommendation is spam if the account promoting it is ten minutes old and talks about nothing but the product, but if it's a two year old account with seemingly normal history and lots of likes/upvotes/shares/whatever. The very generic comments and photos is one common approach for doing that, because it's easy to do. A somewhat more difficult to spot way that they do it is by copy/pasting old comments and posts."
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808b12 | Why is the "Censor Bleep" tone so consistent across most media? | Technology | explainlikeimfive | {
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"Traditionally audio equipment is tested by using a reference tone. This is just a generated sound wave, usually with a frequency of 1000 Hz, because that seems like a good enough number as any. Sometimes they'll also play a 100Hz and a 10,000Hz tone to test subwoofers and tweeters, but it's basically an easy way to make sure the volume is adjusted appropriately and all the crossovers are setup right. Since engineers were already testing with a 1kHz tone, they just kept using it when they had to play something over profanity since it was easy to use it again. There's no big technical or legal reason to use THAT sound, it was just easy to do and got the job done.",
"1kHz tone is ubiquitous in broadcast environments. It's used to test audio connections and check levels. When an editor needed to censor something way back when, 1kHz tone was probably right there permanently on a patch panel and only had to be switched with the source audio to mask the naughty word. I guess the convention stuck. The real question now is, why 1kHz tone?",
"Speculating, but I imagine it's because the beep we know as the censorship beep is actually just a basic equipment test tone. The tone itself is as simple as they come - it's typically a c6 sine wave played at the equipment's maximum volume, and that makes it the perfect the perfect tool for a quick interjection of censorship, since it's something that can be invoked just by pushing a button, which immediately drowns out other audio, and which isn't too annoying to the listener. Silence could be used instead, but not without people thinking their equipment was dropping out."
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808b6k | What does the little ball inside a whistle do? | Technology | explainlikeimfive | {
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"text": [
"The ball inside the whistle is not necessary for the whistle to work but serves a purpose. A whistle without a ball has a flat tone that may get \"lost\". In an American Whistle the ball rises and falls as it is pushed around by the turbulence. When the ball moves within the chamber, it creates variations within the pitch, or the trilling sound you associate with a quality whistle blast. [Source]( URL_0 )"
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808lax | In football (soccer), when a player gets hurt, sometimes you see medics spray something on the area that is hurt. What is that stuff and how does it help? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"I know it as the brand we used in school sports (deep heat spray). It helps relieve pain by increasing blood supply up the affected areas (not sure how that works exactly) URL_0"
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80cjwk | How does datamining in video games work? | Technology | explainlikeimfive | {
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"text": [
"You can see Datamining as the following: Imagine you buy a book with 1000 Pages. You can read 300 of these Pages immediately, the rest are hidden behind black paper, because they are not finished yet. There is some content in those sites that has been already written into the book, but isn't final so they don't let the content appear in the readable section. If you take a bright flashlight and shine through the black paper you might be able to see some of the story beforehand without them being released, giving you a clue how the story could go on or even what characters will appear. Same goes for Datamining. Most content that will come with later patches is already in the gamefiles, hidden somewhere. It's just not patched so it doesn't appear ingame. If you have enough time and search through all files for things that are not ingame you find a lot of things that are already there, but not playable right now, giving you clues about what comes next."
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80csrj | What actually happens when an electronic bank transfer is made? | What happens to the physical money? Is it deposited from one bank to another in batches? Does the physical money never move? | Technology | explainlikeimfive | {
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"Physical money never needs to move if you dont sort it in the first place. Lets say you are holding 5 dollar bills each for 3 friends. You put all 15 dollars in your wallet. One friend comes and says “actually make 3 of my dollars go to (other friend)’s set.” Does the money need to move from your wallet, or do you need to just remember that one friend has 2 and the other has 8 of your 15?",
"It depends on the settlement and liquidity associated with that payment type. Some payment types only settle - that is to transfer the actual value, once a day. During the course of the day the banks send messages to each other and represent the balance on customers accounts. However banks, may only transfer the value once at the close of business. Further the values might be ‘netted’ against between the inward and outward payments. Other settlement types include instances where a value of money (in the billions) is held by a central bank. As an example; Faster payments in the UK settles three times a day. Multi lateral deferred net settlement l. Some payment methods, usually high value instructions will settle for each transaction. Real time gross settlement. Deferred net settlement doesn’t happen in the UK but is used traditionally for correspondent bank settlement. Each settlement type has different risks associated with it, settlement/liquidity/credit - having money tied up in - central bank or owing too much money to a bank at the end of the day."
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80dl8k | Why do developers have dataminable content instead of adding it after its ready to be released? | When people datamine games they can find stuff that hasn't been released yet. Whats the point of adding code for the content If developers don't want it in the game yet. | Technology | explainlikeimfive | {
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"text": [
"Saves time. That way when they want to implement it in-game, it's essentially a toggle, instead of forcing all players to download the content, therefore reducing down time when the stuff they want to go live, goes live."
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80e7pv | Why haven't they built video cards with the possibility of using your own ram like they do on every motherboard? | For example, Why can't I purchase a GTX 1080 and use any variety of DDR5 ram I also purchased and installed. Wouldn't that help solve the current crazy of overpriced video cards? | Technology | explainlikeimfive | {
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"text": [
"Replaceable gddrx modules would add quite a bit of design complexity and cost to a card, while having little benefit as few users would even consider adding more vram (something that also isn't commercially available) as a way of upgrading performance. Also, given that memory is one of the limiting factors on graphics supply, replaceable modules wouldn't likely help out, and likely make the problem worse in the short term, as retailers and distributors would have to stock new memory modules.",
"Also they did this in the early (Mid ?) 90's .. I'm guessing the technical aspet of having upgradable video ram slots made it either too expensive or difficult to manufacture. Altho i did like added an extra 2Mb to my ... tries desperately to think which card i had at the time .. Was either one of Matrox G200 / Rage 128 / could have been original Voodoo 3dfx? Maybe it was before those ? Edit : A google image search confirmed it was the matrox G200"
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80fv1m | Why do gas stations make you go inside if there's less than $100-$200 on your debit card? | Technology | explainlikeimfive | {
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"text": [
"I've never had that happen, and my debit card has had less than that before. However, I'd assume it's something to do with putting holds on your account. I got gas once at a gas station and they placed a $50 hold on my account (I only got $20 worth of gas), the difference was refunded a few days later",
"Basically it lets them get their money first. The way gas stations generally (at least used to) work is that the initially put a \"hold\" on your card for some set amount. Then when you actually finish pumping the gas they drop that hold down to the amount that you actually owe them for the gas. This works great in ensuring that you can actually pay them... unless you don't have enough money to meet the initial hold. If that is the case then they want to make sure you actually have enough money to pay for the gas you are going to buy (rather than you filling up and then not paying them or having the payment bounce) so they make you go inside."
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80ktei | How is it possible for humans to "lose" or destroy the technology that sent men to the moon? | URL_0 "we dont have the technology to do that anymore, we used to, but we destroyed it" | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"He means the US doesn't have a ready-to-go Apollo rocket + command module + lander. The last of those contained 70's technology. They were serviced in engineering hangers geared up for 70's technology, running software probably initially written with pencil, probably using communication systems that were turned off in the early 80's. Both the rocket itself and all the infrastructure to support it are long gone. He doesn't mean the US couldn't build the same thing again (well.. he might mean _some_ of the old engineering specs are literally missing) but it would take an immense amount of time and money to get a 21st century version designed and built.",
"We tend, in our everyday lives, to think of technology as the _gadgets_ — e.g., the phone, the computer, the _whatever_. But technology is really about _systems_ — it is about the systems that are used to produce the gadgets (which, depending on the technology, can include vast supply chains, production facilities, and long-honed expertise), and the systems that maintain and keep the gadgets operational (the people who know how to use them, to fix them, to repair them, the parts necessary, the fuel, etc.). If you stop maintaining that system, it becomes increasingly hard to say you still \"have\" the technology. Especially with something as complex as, say, a space program, where many of the pieces are custom-built and require mammoth facilities to keep working. This is not to say that we could not _rebuild_ that capability. We still know _how_ they did all those things; the _knowledge_ is not lost. But knowledge is only _part_ of a technological system, and often it is not even the most important part. (Separately, it _is_ possible to lose knowledge, especially knowledge that comes embedded in human beings — what is known as _tacit knowledge_, but you can think of as \"know-how\" or even just \"experience.\") Technological systems require a lot of work to keep working. This is true of even seemingly simple technological systems, like roads (visit New Jersey if you'd like to see what it looks like when you stop maintaining the road infrastructure), certainly for complex systems like trains (visit New York City if you'd like to see that), and _definitely_ for highly-complex, highly-specific systems like \"the capability to go to the Moon.\""
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80l3pe | When you increase the volume in a tv, what actually causes the sound to become louder? | Technology | explainlikeimfive | {
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"text": [
"Electronic loudspeakers generate sound by vibrating a *diaphragm* (a thin, semi-rigid membrane made from various materials) against the air. The diaphragm is made to move because it is attached to a magnet, which sits inside a coil of (e.g. copper) wire. When an electric current is passed through the coil, this creates a magnetic force that pushes or pulls the magnet. By reversing the direction of the current at the right rate, the diaphragm can be made to vibrate (move to and fro) at any desired frequency, which causes the air around it to vibrate at the same frequency. These air vibrations are what we perceive as sound, and the pitch of the sound is determined by the frequency of the vibrations, with fast vibrations perceived as having higher pitch. The loudness of a sound has to do with the strength of the vibrations: not how quickly the air molecules are moving to and fro, but how far they move in each direction while doing this. A loudspeaker can control this by moving the diaphragm back and forth a little (say 1 mm) or a lot (say 5 mm) in each cycle. That is, by passing a stronger current through the electromagnetic coil, it can push and pull the diaphragm in and out further, thereby pushing against the air more strongly and causing stronger vibrations. So to summarize: when you increase the volume on your TV, the current it sends to its loudspeaker(s) is increased, causing the diaphragm(s) in the loudspeaker(s) to vibrate more strongly, which creates stronger vibrations in the air, which you perceive as a louder sound.",
"The speaker cones vibate harder, meaning they push harder against the air, which translate to larger volume."
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80ovns | How do musicians make such great sounding remixes? | Technology | explainlikeimfive | {
"a_id": [
"dux3c11"
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"text": [
"Yes one way is you can isolate the frequencies you need with an eq. Then you can set a narrow band to exaggerate them if you really want. You can sometimes hide the remnants of what’s left like a hint of drums or guitar etc and bury them in the mix. Another way is they recreate the parts they want. And lastly is what you said, getting raws or stems from the actual session. Source: noob engineer, and I’ve done all these."
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80p27k | Why does the colour red look so bad on TV and in compressed video? | Don't know if this is just me, but almost every time I watch TV or video and there's a bright red it looks extremely bad (pixelated and not blending in correctly), but all the other colours look okay. The effect is lessened by turning up the quality on online video (YouTube, Netflix, etc...) to 1080p or something like that. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"You have good eyes. In the same way that dogs and cats can't see all the colors that the human eye can perceive, and in the same way that our eyes can't see color wavelengths that exist outside of what we call \"the visible spectrum\", our camera sensors and LCD screens can't sense or reproduce all the colors of the visible spectrum that the human eye can perceive. Our digital sensors are particularly \"blind\" to a range of colors in the red range. You can see a visual explanation of \"color gamut\" in this image search: URL_0"
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80p9my | How does a BIOS update 'brick' hardware? | Technology | explainlikeimfive | {
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"The bios contains the basic functions of the motherboard. If it’s not properly loaded then the motherboard won’t be able to boot. If the mobo has dual bios then you can boot the other bios and flash the bad one. Otherwise you need to replace the memory chip on the motherboard that contains the bios with another one that has a good bios loaded, this is generally not user doable. Otherwise buy a new mobo or send it in for repair.",
"It's not always bricked. Sometime its possible to reset to factory defaults, sometimes one has to flash the bios, sometime taking the battery out resets it. URL_0 Is the first definition I came in Google.",
"The BIOS (using the term a bit generically) is the first piece of code loaded when a system starts, and contains enough information to start the system and pass control to a piece of code on a storage device or other source. If for some reason, that code is messed up in some way, like an interrupted flashing, the system may be unable to boot as the instructions for booting may be missing/corrupted. Some enthusiast and server motherboards might have a redundant setup, or a backup method of loading a bios file, but for the majority of boards, a corrupted bios means a motherboard that is effectively dead to the consumer.",
"BIOS stands for Basic Input Output System. Before the operating system is loaded, it has settings that allow a computer do things like accepting keyboard or mouse input to change settings, display output on the monitor and read and write to the disk where the operating system lives. If the disk is disabled or the information is incorrect, the OS won't load. If the keyboard and mouse are disabled or the information incorrect, you can no longer change any of the settings, and your computer becomes non-functional. Some devices are designs to intentionally brick themselves if you violate their security. Other times it just happens by accident, through poor design, or my user error.",
"The BIOS is the very first thing that is \"looked at\" when the hardware boots up. Think of it as if you woke up everyday and to do something relatively complex so that you can get on with your day, and there were instructions (BIOS) by your bed every time you did so; whenever you fall asleep (the hardware turns off) you forget what you're supposed to do and how you do it. Now suddenly, you wake up and there's *nothing* by your bed. No directions to do anything. So you're just sitting there, with nothing to do because there are no instructions to do anything. You are bricked in your home. Generally, no one else can enter to help you as everything is locked down because you haven't even been able to open anything. Sometimes, there's a backdoor someone else (you IRL, attempting to fix the BIOS), or the manufacturer the can open it (you sending or carrying it in). If you're having troubles, [this article might be able to help you further]( URL_0 ). It is somewhat dated, but most all of the steps are good for troubleshooting.",
"Imagine I have a piece of hardware with a power button that goes into a chip that has some pins, let's say it's an 8 pin chip that looks vaguely like this: URL_0 Let's say the chip is programmed so that the hardware only turns on if it gets power to pins 1 and 2, with pin 1 power being from the outlet (always on) and pin 2 power being the lead from the power button, so the chip 'sees' that pins 1 and 2 have power when you push the power button (off most of the time, on when you push power). I put in a firmware update that tells the chip to instead look at pin 3. Now when you push the power button, the physical connection is still setting pin 2 to 'on', but nothing happens since the chip is looking at pin 3. The hardware will never turn on again unless the chip is replaced. Failed BIOS updates do something similar - it corrupts the firmware at the chip level to do things that are unexpected, and that can cause all sorts of failures at every level."
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"https://www.mouser.com/ProductDetail/Microchip/ATTINY13A-SSH/?qs=KvkD1x8ydu6qSJYv3rwfIA%3D%3D&gclid=EAIaIQobChMIia_Hm-rG2QIVhZF-Ch0LtwabEAQYASABEgK83PD_BwE"
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80px5b | How does USB 3.0 have such fast transfer speeds compared to USB 1.0/2.0? The plugs and ports are exactly the same. | I always wondered this. How can two versions of USB have wildly different data transfer rates, when they all have the same plug shape and the same 4 contacts on the plug as well as the port? I'm not talking about USB-C; just plain old USB, obviously. | Technology | explainlikeimfive | {
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"text": [
"USB 3.0 (all variants, ignoring type-c) uses a 9-pin connector instead of 4 on previous versions. For the type A connector (the ubiquitous rectangular \"host\"-side connector), the same form of connector was used, with the additional 5 pins cleverly spaced in between the existing 4 pins (and offset so the 4 older pins connect first). Other connectors are a bit less elegant, with a new portion attached to existing connector standards, or in the case of USB type c, a new connector entirely. In addition to the single pair (used as a single directional link) in the 2.0 standard, the usb3 cable adds in 2 new pairs of wires for data transfer (one in each direction) and an extra ground pin.",
"They are not exactly the same. USB 3.0 has 5 more wires in the connector that run parallel to the existing 4 from 2.0 (so that it's backwards compatible). It also uses full duplex signaling instead of half duplex because of those.",
"The speed at which you can transfer information depends on how quickly a signal can be turned on and off on a given wire and how quickly one can recognize the incoming signal. Newer standards have higher speeds at which those things can be done as they use better technology, and it really has nothing to do with the wire itself. The point of a standard is that it establishes all devices which comply with the standard are capable of the indicated transfer speeds."
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80srmm | Why do some lamps require two turns of the knob to turn on whereas a typical wall switch is just one flick | Technology | explainlikeimfive | {
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"text": [
"Because these lamps are set for a 3 way bulb but only have a standard bulb in them. A 3 way bulb has a low medium and high setting vs a normal bulb just being on or off.",
"Three way bulbs have a 4-step sequence (off-low-medium-high). Then you put an ordinary bulb in them it becomes off-off-on-on."
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80u7gk | Why does smartphone screenes show micro abrasions when most metals cannot scratch it? | Technology | explainlikeimfive | {
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"text": [
"Although metals are tough, they are not quite as hard as you think. You can get a tough metal by quench hardening carbon steel, but even those are scratched by things like sand and rocks. What I’m getting at here, is that sand and rocks are harder then metals at the molecular scale, so they scratch things metals can’t. However, because of this hardness comes brittleness, which is why rocks and glass (sand) break instead of bend.",
"The abrasions are caused by specs of dirt, rock, sand that get rubbed against the surface from dirty fingers, dirty pockets, etc. Metals are not all that hard, no where near as hard as rock. Hardness is what matters when we're talking about one object scratching another."
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80ywyw | How does an electric faucet conserve water as opposed to a normal faucet | Technology | explainlikeimfive | {
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"You mean those with sensors that turn on and off when you come near them with your hands? Well. If you turn on the water yourself, you’ll use some water during the time it takes to put your hands under the water. It probably adds up to a few % of the total amount of water you need to wash your hands. And the same when you turn it off. It doesn’t seem like much, but public restrooms in amusement parks and shopping malls use ridiculous amounts of water. Cutting away 5% of the water consumption just because you have faucets that are quick to turn off can have a pretty remarkable environmental impact. I can’t imagine it’s the first thing you do to minimise your environmental footprint. But among other things, it seems reasonable."
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80zyky | Youtube videos purporting to review newly announced tech with still pics and synthesised voice. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"People who want easy money can for the clicks with almost no effort. The still images are much easier to edit than actuall video and you don't even have to try to speak clearly, just write your script and let MS Sam know handle it. Little work for some bonus cash."
],
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80zz41 | How do bomb disposal teams decide which wire to cut on a bomb and how do they pinpoint where a bomb is? | I’m referencing towards “The Hurt Locker” film. The scene where Sgt. James finds one bomb which leads to several other bombs, how did he know the first one was there and know which wire to cut? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Ninety percent of the time, they find a bomb the same way non-explosive-ordnance-disposal (EOD) guys do - someone sees a loose piece of trash that seems suspicious, someone just *said* something to a passing patrol, or there are signs that something's been buried - loose dirt, suspicious tracks, etc. Often, there are only so many places to put an explosive in such a way that they'll be useful - along convoy routes, in areas where troops are passing by somewhat regularly, etc., and so, upon approaching this sort of an area, the guys trying not to get blown up are going to be eyeing every dead animal, trash pile, upturned patch of dirt, and so on with extra wariness. In some of the less hospitable portions of the Middle East especially, the bomb isn't on a timer like you'd see in a Bond film - a lot of times it's just an old land mine someone found in an old Soviet dump, which has its own set of drawbacks - maybe it needs a certain amount of pressure, maybe it's unreliable and corroded, maybe it's only going to go off if something large and metal drives over it - or there's a simple circuit connected to an antenna. The latter are more common then you'd think, and they require someone watching the bomb's location with a cell phone to actually detonate. So if a patrol sees someone eyeing the area who's not got a good reason already to be doing so... well, see above: it's a pretty good indicator. And most of the time, there's no particular rush after the thing's been spotted - the troops are pulled back, civilians are warned off the area, and people are posted at a safe distance to redirect traffic. There's no sense risking someone - a very well-trained and in-demand someone, to boot - to go in and cut wires and the like. Nine times out of ten, it's a simple matter of just blowing the thing from a safe distance - send a little robot in to place a charge and press the button when it wheels merrily away, toss an explosive on top of it and light the fuse, and so on. These aren't bombs in the sense of old WWII bunker-busters; if you know it's there, it's just easier, faster and safer to get anyone and anything out of the likely blast radius, back up a little more, and blow the thing up - most likely, it won't have an effective casualty radius of more than few meters anyway, and the end result is just a hole in the road and the EOD guys waddling away to their next date with destiny.",
"That's movie nonsense. Bomb disposal is not done by a guy running up to it and trying to decide between the red and the green wire. URL_0 In most cases, bomb disposal involves either trying to neutralize the electronics by dousing it in water or detonating the bomb in a controlled fashion.",
"Cutting wires to defuse bombs is something that almost never happen in real life. There could be a number of different booby traps and failsafes in a bomb that you would not know about. Defusing bombs only happen when the design of the bomb is fully known and the cost of blowing it up on site is too high. Defusing is more common in wartimes due to these factors. However even during a war with known bomb designs defusing is a dangerous task. A bomb have two main components. There is an explosive and a trigger mechanism. These are connected with a detonator, either embedded in the explosives or connected with a fuse. If you cut the wire or fuse connecting the trigger and the explosives then the bomb is not able to go off. That is unless there is a secondary trigger hidden in the explosives or if there are several detonators and the trigger mechanism monitors each one of them to detect when they are being cut and detonates the bomb or if the wires between the trigger and explosives are unaccessible. There are also attacks that works directly on the triggering mechanism. Things like disconnecting the power, removing the trigger switch or otherwise disable the trigger mechanism might work in certain cases. Something that is sometimes attempted is to use explosives to cut multiple wires at once or destroy the trigger mechanism without causing the main charge of the bomb to go off. However this have a big chance of either detonating the bomb directly or not defusing it causing it to go off on its own. So it is usually done as a last attempt when you are planning on blowing it up in place anyway."
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810cp7 | Why do bugs in videogames appear or not sometimes if it's the same situation? Wouldn't it happen always if it is the same situation? | Technology | explainlikeimfive | {
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"Its not *exactly* the same situation, some things require some very very specific sequences of events. Even the perfectly repeatable ones are often rather obscure Some bugs are caused by memory errors where everything *was* the same until some random bit flipped and now its in a slightly different state. Maybe a process got stuck in a loop so it couldn't perform its housekeeping routine so you saw something you shouldn't have. Some bugs are just caused by weird seemingly unrelated occurences. Maybe it only occurs on Wednesday in September after the 10th between 10am and 12:59pm. Even if you go through the exact same steps, if you're testing it on tuesday you'll never get it. If they were obvious and easily repeatable they would have been caught before, every bug you see has a relatively low occurrence rate, but with thousands of users logging hundreds of hours you can find some really obscure bugs and glitches",
"As a computer developer if you can get bugs to happen reliably it is amazing and that is usually the first step to fixing them. This is because the vast majority of bugs (excluding multi threading stuff I'll talk about at the end) is repeatable in some fashion, so if you know how to recreate it then you can figure out what is causing it and is the problem. As for why it might not happen is usually because of unnoticed edge cases. For example maybe a bug only happens when the third digit of a player's score is a 6. Maybe it only happens if two items collide at precisely a 42 degree angle at exactly the same speed. Edge cases like this are virtually impossible to replicate on command by humans, so they can be difficult to track down. Bugs might also be affected by things going on behind the scenes. Maybe a crash only happens if a player walks through a doorway at a specific point in the loading process for the next area, which might set up a bad memory address so that the *next* time a player walks through a doorway the game crashes (but not until then). Things like this are totally invisible to the player, but can still cause bugs. And multithreading adds it's own hellish layer to issues by opening up all sorts of timing issues where things like whether or not you have other programs on your computer running or what CPU you have can change whether bugs show up or not. Some of the worse bugs like this can almost be impossible to debug, since adding debugging code to see what's causing the problem can make the problem appear or disappear. **TL;DR**: Bugs always have some repeatable way to make them happen, but that chain might be really complex and hard to figure out. A huge part of a bug fixing computer programmers job is trying to figure out what exactly those chains of events are to work backwards to the original bit of code causing the issue and fix it."
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8116yk | Why is the camera recording quality noticeably worse when the same broadcast is reporting news outside of North America or Europe? | Technology | explainlikeimfive | {
"a_id": [
"duzpi8c",
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"text": [
"Not every country has the necessary electronic and technological infrastructure to transmit and receive the crisp video and audio that's most easily found in such countries as you named.",
"Europe uses a video standard called PAL. North America uses NTSC; the conversion between the two is what causes the picture quality differences."
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814xga | What makes a battery "rechargeable" and why do they get worse the more times they have been recharged? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Theoretically, all batteries are rechargeable but some are better than others at being recharged. Batteries make electricity via the chemical reaction route. Essentially what you have is a chemical goop in between layers of film that, when it's hooked up as part of an electrical circuit begins reacting and generating voltage. It's the same thing, in principle, that you have going on inside a lemon when you put those two metal pieces into it in science class. Eventually, the goop is depleted of it's ability to do what it does and the reaction stops. This is what we call a \"dead\" battery, but that reaction can be reversed. You just have to apply an electrical voltage to it in reversed polarity. (i.e. + to +, - to -). The chemical reaction works the same way backwards as it does forwards. And therein lies the problem. Most of these chemical reactions also require heat from the environment around them (which is why cold batteries work worse than warm ones and why 'baking' a battery sometimes get a few more minutes or hours of juice out of it) they also generate pretty small voltages (typically around 1.5v or so). When charging them that heat comes back out and (unless you want to take as long charging the battery as you did draining it) it comes out much faster. Heat + goop in a sealed container = pressure and pressure = pop. Batteries labeled \"rechargeable\" both generate less heat when being recharged and are engineered to handle that heat better. We used to use Nickel-Cadmium (NiCad) for this but those batteries didn't charge very fast and really couldn't provide enough current to power modern electronics so we went to Lithium Ion based batteries. Those can charge and discharge much faster than NiCad but they come with a really awful couple of limitations: 1 - Unlike NiCads, they don't \"tell you\" when they're full. They just start heating up *really* fast. 2 - When they pop, the elemental lithium in them reacts *violently* with oxygen. Hence all the videos of batteries going up like road flares when somebody punctures them. Both batteries develop a \"memory\" over time. NiCads did it very fast. Lithium Ion batteries more slowly ( at first ) and then very quickly after around 300 charge cycles or so. Every time you run the reaction (in either direction) some of the molecules in the goop break and can't be used as part of the charge cycle anymore.",
"There's juice in the battery that holds electricity. The juice can run out of electricity but it can also be refilled. Every time the juice refills with electricity a tiny bit of the juice turns crusty. Eventually there's too much crust for the battery to be worth keeping around because it doesn't hold enough electricity with its juice."
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