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cszjv9 | How are computer chips with billions, or now trillions, of transistors made? | I just saw on r/tech that a chip with 1.2 trillion transistors was made. Surely, these aren’t made by hand, and I don’t understand how anything could make this chip, hence the post. | Technology | explainlikeimfive | {
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"The general process is called photolithography. Basically you shine light through a stencil that hardens a chemical coating. The non hardend chemical (photo resist) gets washed away, and various chemical processes are used to add or remove layers different types of silicon or otherwise to the chip. In the early early days when transistors were big ICs could be designed by hand, and shrinking down a stencil would be about as complicated as reducing the size of an image on a photocopier. Nowdays the stencils are so small that the masks are made by etching with electron beams. And the detailed steps are way way more complicated than simple photolithography. We can't really even use visible light anymore to expose the stencil because of how hard it is to get what basically amounts to parallel light. The general principle is the same though. As for how they actually design the layout the answer is that its done with computers and software written to specifically plan the layout, and simulate its function. It generates a ridiculously detailed image for a silicon wafer wafer that can be used to control the electron beam. And by ridiculously detailed I mean like Terabytes of info detailed. A single wafer will always have many individual chips made at the same time. For stuff like GPU chips the entire design process of getting a working mask is in the hundreds of millions of dollars."
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ct0fcm | New TVs boast the ability to display more colors. What colors can't a TV display? | New TV's are HDR, or high-dynamic range and they boast the ability to show 10 or 12 bit color. Once there are enough "bits", does that mean that they will be able to show every color? How many bits is enough? Or are there colors that TVs and computer monitors will never be able to show? | Technology | explainlikeimfive | {
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"Theoretically, there is no number of bits which would be able to display \"all colors\". However, many TVs can already display PRACTICALLY all colors."
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ct19sh | Managing Human Waste | How do we manage human waste? On average a persons produces 145 kg of poop per year. That means that yearly we produce globally 1 billion tons of poop or 2,7 millon tons per day. So where is all this poop going to? | Technology | explainlikeimfive | {
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"In the developed world, sewage treatment plants filter out \"solids\" and decontaminate the water before discharging it. The discharged water won't kill you if you drink it, but it's still usually kinda dank. The dried solids are landfilled. In the not-so-developed world, the sewers just dump into the ocean or a river somewhere. Yes, it's a problem.",
"So from the toilet it goes to the sewer line. Then it gets gravity fed or pumped via pump stations to your treatment plant. Treatment options depend on the volume usually measured in millions of gallons. The first step in most treatment plants it to filter out not organic solids, so trash, metals etc... Once the mix is organic waste you can treat it. A few options are anaerobic digestion, which in a big tank the solid waste is eaten by bacteria and it farts out methane. The methane is either burned off or used to power generators to offset the cost of running the plant. This will eat a majority of the solids. The next is a centrifuge. It spins the water out of the mixture and forms a cake. They add lime to help dry it out and it gets loaded on a truck to be used as a fertilizer. The water left over after the solids are removed get treated with a bit of chlorine and other chemicals and get pumped into a local water table. Maybe a river. The 3rd option is a septic tank if you can't connect to the sewage system. It uses the same concept as anaerobic digestion, solids are slowing eaten and methane is given off. That's why there are many septic safe products on the market so that they don't kill off the bacteria. They get pumped out as needed and the solids are taken to a waste treatment plant for further processing.",
"Solid waste is filtered out at the water treatment plant, and it ends up in landfills. Fortunately, most of this solid waste is biodegradable, so a good deal of it will be gone even before it reaches the landfill. PS: Your poop will likely be sludge by the time it reaches the treatment plant.",
"Mostly with sewage treatment systems they feed it to different types of bacteria. Otherwise for the remaining sludge it gets either composted for fertilizer, or tossed in a landfill. Sometimes its burned. For individuals without sewage options you an usually just bury it in a big hole and cover it with dirt and leaves. After a while you get compost."
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ct2csy | What tricks are used to get the sense of scale and vastness in Open world Games. | I have played my share of open world games and recently started Assassins creed Odyssey which got me thinking. How can they make a world so vast when travelling on foot and yet, in comparison, so “small“ when travelling on horse or ship. While standing in the middle a village it feels huge but standing on a overlooking mountaintop its only a football field in size. Overlooking the highest point, the whole world is within eyesight but also seems extremely vast. That city in on the horizon looks miles away yet travelling as the crow flies its “only” 500meters away. What trickery are they using to get this sense of perspective and scaling. | Technology | explainlikeimfive | {
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"I think mostly with detail and mobility. Like as a person we don't get a nice 3rd person view which is much higher than a normal view. In a city you get to see more at once. Also we can't exactly climb buildings in an instant for a better vantage point. And your character can run everywhere he wants at unreasonable human endurance levels. With long distances your character can also cover large amounts of territory at unreasonable speeds. And you usually don't get to ride a horse or a boat instantly without prepwork or getting stuck in traffic. So technically everything is probably to a real life scale, but by ignoring all the mundane stuff like vehicle maintenance and endurance you get to cover a lot more to scale distance than you normally would.",
"Atmospheric perspective plays a big part in this. As you move further away from an object, light is diffused by the air, making the colour of objects appear less saturated and lighter. [Like this]( URL_0 ). Open world games tend to crank up the atmospheric perspective to amounts higher than you'd see in the real world. This makes distant landmarks like mountains appear to be much further away than they really are. Level design is also important. Open world games typically restrict you from walking in a straight line for too long. You have to navigate around obstacles which makes the distance seem greater than it really is."
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ct5thm | why do CDs have to spin to be read? Why don’t solid drives have to spin to be read? | Technology | explainlikeimfive | {
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"The data of a CD is laid out in a spiral much like the groove of an old vinyl record. The read head scans the digital markings as the disc spins in order to read the data. Solid state drives are simply large banks of addressable memory. There is no disc, no read head, and no perceptible movement at all.",
"A CD has its information written by a laser, and it's written in a circular pattern on the disc. So to read that data the disc is spun, and a laser can move back and forward and read the bits of data it needs to find. Traditional hard drives work in a similar way. A solid-state drive has no moving parts, it uses flash memory (circuits) to hold data. No moving bits needed to find the data which makes it much, much faster too!"
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ct6e7r | How can devices/phones constantly listen for "Hey Siri" (or Alexa, etc) without noticeable energy drain, despite feeding a neural network with constant microphone input would need lots of energy/cpu cyles? | Technology | explainlikeimfive | {
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"I’m not sure on the android side of things, but iPhones have a coprocessor (dubbed M9, M10, M11, and M12) that handle this task *specifically*, which allows for lower drain. It’s basically a chip with one or two tasks. Here’s a good article that describes it. URL_0",
"They do not feed any neural network in order to listen for those cues, is the answer. The personal assistants, phones, etc. with “wake words“ have small dedicated processors that are only capable of listening for very specific combinations of syllables. Usually the word, like “Alexa,“ is a word with very different and distinct syllables that do not typically appear in that order elsewhere in the language, meaning the chip has an easier time of it than normal speech processing software. It would be too computationally expensive for these processors to run actual software, so the wake words are usually hardcoded in hardware or very low level firmware, which is why they cannot be configured to wake on any word the user wants. As an industry, we still don’t really have the capability of listening to and interpreting speech context well on a small device, without uploading it to the cloud for processing. But if we were uploading everything the mic heard, not only would it be incredibly obvious and impossible to hide from any user network or router software, but we would also blow through your data caps in a matter of days and the secret would immediately be out.",
"It's the same reason why you can hear someone say your name in a crowd. It's easier to listen for one word than to every word. There's a part of your brain that's always listening for your name, even when you're not paying attention to a conversation. Similarly, devices have a part of their \"brain\" (processor) that's listening for their \"name\" (wake word). That's why each device can only have one or two wake words: they're built into the machine.",
"It is a much bigger task, computationally, to understand speech rather than to detect a specific word or phrase. On all of these devices, a small, low power processor is all that is needed to detect the keyword/phrase to start streaming audio to the servers that actually do the computations.",
"Identifying speech (or at least a small set of specific words) is surprisingly low-impact, computationally. I had a gaming voice-command program in like 2003 that ran light enough that it didn't interfere with games, and modern phones are a whole lot more powerful than that desktop was.",
"I work in MEMS microphones. In more advanced designs the ASIC chip in the microphone will hold the operating voltage at a “low power mode” until the vocal command is heard and then it will switch the device to a “high power mode”. This usually means better SNR and a wider bandwidth.",
"Theoretically, it doesn't take that much for a simple neural network to run. It doesn't have too much complicated math. In its core philosophy, each \"node\" of the neural network just multiplies each input \"neuron\" value by a weight, then adds up the total value from all the weighted inputs and sends it out as the output. (There's options for a little bit more than that, but at its most basic, it's just addition and multiplication) Of course, the reality is it can get very complicated very quickly. First of all, neural networks have multiple nodes and layers which can exponentially increase the number of calculations required, however simple. You can also have layers of multiple, discrete neural networks themselves with intricate relationships between them and how they pipeline data to each other. The obvious example being image detection where you'll run into phrases like convolutional neural networks which can be incredibly computationally intensive. But even then, algorithms like YOLO (seriously, that's what it's called) allow some image detection to be run in real-time video (granted, on something like a serious desktop at very minimum, not an Alexa). But sound, especially when pared down to only looking for a certain word or phrase (\"Alexa\", \"Ok Google\"), is a lot simpler. First off, before even getting to the neural network, you can have non machine-learning, manually-written checks first. E.g. it could be something that first checks the basic waveform is roughly close enough (e.g. right number of syllables or something like that). Similarly, the neural network itself can be designed much simpler since it's only trying to process a short phrase, not a full sentence of varying length. The truly intensive part of neural networks is training them. That's a super iterative process that requires lots of data and a bit more complicated maths. But your home device or phone isn't doing that ever. At most, training data your device may provide is uploaded to Google/Apple/Amazon which does the training on their servers."
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ct6g76 | How do search engines get results so quickly? | When I look something up on google or look up a name on Instagram I get results nearly immediately despite there being like billions of results for the search to look through. Even just making a search for a specific file on my laptop takes a while, so how do companies like these do it so fast? | Technology | explainlikeimfive | {
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"Google has an army of computers that are constantly \"crawling\" the web in the background, 24 hours a day and analysing the information on each website. This is a slow and never ending process. They use the information to build up a database of essential keywords for each website. When you type something into the Google search box, it searches its own database rather than the whole internet but will provide a link to the current live page. This is a much faster process but does mean that what it is searching is always a little bit out of date. That is why sometimes you get a link to a site that doesn't exist because it has closed down since the last time Google analysed it. In many cases, if the analysis shows that a site is popular (has a lot of traffic, and links) then Google will actually copy it and create a \"cached\" copy of the website on its own servers. This means that it can actually do a fast full text search on those cached pages rather than rely on just keywords and without being slowed down by internet speeds. The link it gives will still be to the live site though rather than its own copy. This is worth knowing because sometimes if a site has changed or even been taken down since the last time Google cached it you can still see the old version by clicking on the little down arrow next to the entry in the search results. This will bring up the cached version rather than the current one.",
"There are many method but a simple would be to have many server. Each server contains 1000 possible result. And they all search on their side. So instead of wainting from one server going trhough 1000'000 possiblr result you have all the server in parrallel who only look 1000 result each",
"Software and Math is amazing: Lets start there. On the software side, when you're doing your google search, sure you're getting 1,237,933,416 (in actuality, there's probably 1,249,518,232) matches, but all it really needs is the first 10 to fill the page you're looking at. So bam, there's your page. Get the link, some text surrounding your search terms, and plop those on the page; great! Now how does it pick the top 10? I'll explain how basic search engines might do it, and then posit a simple explanation of how google does it: TF/IDF - The basic Search Take some document (or web page) and count all of the times your search terms show up in it. Divide that by the total number of words in the document and you have a resultant score. so lets say we have two documents: **quick brown fox jumps over the lazy dog** **quick brown fox is cool** a search for *quick fox* would yield scores of 2/8 & & 2/5 respectively. With the latter being a higher score, it would rank higher in results & #x200B; Google Magic - The life blood of the internet (I'm probably wrong here) Take some document (or webpage) that has a good score (relevant) and then associate scoring with trusted/established domains and then mix in some scoring with other **relevant** pages that link to those pages. & #x200B; Again, top scores win out so if you search *microsoft* , then (ignoring the advertised results), you'll likely get [ URL_0 ](https:// URL_0 ) at the top because it's relevant (obviously), it's a trusted/established domain, and lots of people link there. However, if you search *consul python module list all keys*, you'll get [ URL_2 ]( URL_2 ) as it's relevant, trusted, and likely linked from loads of places where others have documented its text."
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ct6s5b | How do the cables that the Department of Transportation stretch across the road accurately measure traffic? | Technology | explainlikeimfive | {
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"they are pressurized tubes and every time a car drives over the tube, the pressure shift on the tube flips a counter. You may have seen something similar to ring bells at gas stations or car repair shops to notify attendants to come.",
"That tube, actually called just a \"Road Tube\" is just a hollow piece of rubber. What it does, when you run over it, is send a pressurized puff of air into a counter that just records how many times it gets hit. Sometimes they are paired with cameras, but most of the time they are just static tubes and record the number of times they get run over in a certain amount of time. Sometimes, you'll see 2-6 of them in a row, mainly for redundant counting and accuracy by bulk sampling of the same tire hitting the tubes that many times. So if one counter gets stuck at 50, and everything else got run over 200 times, you know that sample was bad."
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ct79qi | Why is it so hard to port console games to PC and vice versa? | Technology | explainlikeimfive | {
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"Because you literally have to rewrite the software to work on a new console if there doesn't already exist a way to play the game on the console. Just like your body has nerves, and bones and muscles etc. to make you work, a computer works much the same way. If you just... Take a kidney out and put it in someone else, its no guarentee that its going to work, just that you put a kidney in them. You have to make sure everything is compatible, that the operating system and the game can talk to one another, that they display properly, that they have the same blood type."
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ct7iy2 | How do batteries charge faster than they discharge? | Technology | explainlikeimfive | {
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"Batteries have maximum charge and discharge rates. Offhand, I can't actually think of any rechargeable battery that has a maximum charge rate that is greater than its maximum discharge rate. So, the short answer is, they don't. All or almost all batteries \\*can\\* be safely discharged \\*faster\\* than they can safely be recharged. But in most cases, the device using the battery is drawing power at a rate far below the maximum discharge rate for the battery, so it takes a long time to discharge. But the charger will recharge it at the maximum rate, so it charges back up quickly. A 'C' rating tells you the maximum charge and discharge rates for a battery. A LiPo battery might have a 1C charge rating -- meaning it will take 1 hour to charge. But a 20C discharge rating -- meaning it can be discharged in 1/20th of an hour. Or 3 minutes. A car battery (Lead Acid) has around a 1/10C charge rating. Meaning it would take 10 hours to charge it from completely empty. (Though, completely discharging a Lead Acid battery is very bad for it.)"
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ctay2d | My hotel clock is apparently a new model & has two USB charging ports, one 2x the amps of the other. Why is this common, & why not just make both the higher amperage? | Technology | explainlikeimfive | {
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"A 2A + 1A duel charger requires a 3A power supply, and that's cheaper than the 4A power supply that a 2A + 2A duel charger would require. When your making 1 million charging clocks a $0.10 cheaper power supply is a savings of $100,000.",
"Some devices require lower current. I have one that requires a charging source under two amps. I suspect this is related to heat problems in cheaply built charging circuits."
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ctbl7y | What makes the https protocol secure? | Technology | explainlikeimfive | {
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"The 's' in https means secure. Jokes aside, https uses SSL/TLS encryption between your browser and the webserver. There are groups called Certificate Authorities (CAs) who exist to vouch for the identity of different websites. They use keypair cryptography (in which there are two keys, and you use one key to encrypt something and only the other matching key can decrypt it) where the website keeps the \"private\" key to themselves, and publish an SSL Certificate, which is basically the \"public\" key that matches the private key, paired with a promise from a CA promising that it's the real public key that matches their private key. Then you download a webpage via https, it arrives encrypted. You then unencrypt it with the website's public key, and since the CA promised that it's the right key, you know that it was encrypted with that websites private key, and so the webpage actually came from that website and not someone in between you and the website. Your response to the website (eg your password) is then encrypted with their public key, meaning that only the website can unencrypt it since only they have the private key."
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ctbpjp | How does the ‘I’m not a robot” tick box reCaptcha determine whether I’m human or not? How good is it? | Technology | explainlikeimfive | {
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"Before you ever see that checkbox they've already considered a bunch of stuff. Has your browser identified itself as a normal browser (as opposed to just being a script that's running with no graphics)? Have there been a bunch of requests from the same computer? Has there been a pattern of requests for the same content that would normally be seldom requested? Once you've been shown the checkbox they look at *how* you check it. Does your mouse just teleport to the middle of the box? Does it move in a perfect geometric line to get there? Does it move at a perfectly uniform rate along whatever path it takes? Does it take the exact same path that other requests for the same data have taken? By the time you see the check box they already have a pretty good idea that you're not a bot. From there the way in which you check the box gives them a good enough confidence to be willing to let you do whatever you've requested—if they make the test *too* restrictive then real users will get annoyed and not use the site while very motivated bad actors can always just hire an army of people from a low-income area to bypass the captcha anyway. They don't publish the exact methods they use for detecting whether to show you the check or how they judge if the check box was checked appropriately; doing so would make the system far easier to game. The above descriptions are generally accurate, though.",
"It follows your mouse movement. Humans aren't precise so you don't move in a straight line when moving the mouse to click the button. Malicious software move precisely to the point they need to go to. It recognises this and brings up the picture test. Although there's now stuff that moves in a \"human type way\" to combat it."
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ctchf2 | How do people pirate windows keys and sell them for really cheap? | How do they get them in the first place. | Technology | explainlikeimfive | {
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"The main trick for this is breaking regional reselling rules. The price of windows varies greatly by country. These people buy a key whereever it is cheapest, and sell it on the internet. This is not against the law. It could be against the Terms of Service of Microsoft. I've never heard of a version of Windows being disabled because of this. The very cheapest could be creditcard fraud instead. A thief steals a creditcard. They buy a windows code from an online store. They sell the code on one of the code marketplaces. The code gets sold before fraud is reported. Now the store faces a chargeback. But probably is not able to disable the code. Cheap student licenses also exist. I don't know how they are verified these days though."
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ctcsl1 | How do video streaming services work? | I'm very much interested how Netflix (on-demand), and the WWE Network/NBA League Pass works. (Live and on-demand). How do they maintain the data? How do they stream it live or make it like a DVR (pause and rewind)? | Technology | explainlikeimfive | {
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"The same way that anything on the internet works, they download the files :) With streaming video a compressed video is usually broken into a number of chunks say about a half second long each. The actual entire video file is in one piece but each chunk can be downloaded and played independently. On the viewing side as long as the the player can download some basic data like how long a movie is, title, possibly thumbnails for different parts of the movie, it just needs to download chunks as it needs to play them. Now with streaming video compression there's an interesting consequence that results because not all computers will support the same compression formats. The server will usually have multiple copies of a single video all encoded in different formats and qualities to match the users connection speed and encoding needs. The player will figure out what format and quality it needs and request the matching video. With live videos the video is just uploaded to the a server right before players can request to download it. For really popular stuff load balancing gets a bit tricky because a single server can only handle so many clients at once. So usually there are a ton of servers with the exact same copies of the video in different places."
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ctd3p9 | how do whetstones sharpen knives? Why and how are they better than a regular 4$ knife sharpener?? | im trying to figure out the best way to take care of my cooking equipment. | Technology | explainlikeimfive | {
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"Whetstones actually file away small bits of of the metal in order to sharpen the knife in question. This gets rid of any knicks or cuts or damage to the blade edge. This means they can **keep** a blade sharp **and** they can **make** a blade sharp. A cheap knife sharpener is just realigning the edge, it isn't going to actually take away any metal. This means they're really good at **keeping** a blade sharp, but they aren't going to **make** it sharp. On the other hand, those cheap sharpening rods are really easy to learn how to use, whereas whetstones are much harder to learn to use correctly. And those cheap rods are quicker, too. So if you want something to use real quick, grab the rod and fix up your edge a bit before cooking each day/every few days. Use the whetstone once every few months (depending on how often you use your knives) to extend their lifespan considerably. & #x200B; For more information, try this article [ URL_0 ]( URL_0 )",
"Whetstones are like different grades of sandpaper. The rougher the whetstone, the faster it removes material from the blade. Your regular $4 knife sharpener is like really fine sandpaper. It's not any worse than any other sandpaper. It just takes a long time to sharpen something which requires lots of material removal to get sharp. It's great to resharpen a blade which is already quite sharp. Personally I like Skärande knife sharpener from Ikea. It works great, it's cheap, it has 3 different grades, and using it does not require an elaborate ritual like setting up a whetstone in some traditional Japanese way. If you want to spend hours sharpening a knife then whetstones are great. But I don't, I just want to get on with getting my onions chopped.",
"With a whetstone, you are able to control angle and grit. Different types of stones do better or worse based on their composition. Angle of the sharpening allows you to control the \"size\" of the sharpened part of the blade. A higher angle gives you a v shape and and the lower the angle, the deeper and longer the v shape, which means a sharper, thinner cutting edge. Sharpening on a whetstone (or any flat surface used for sharpening) creates a burl, which is why you sharpen an approximately even number of times on both sides to remove that burl which creates, again, a sharper, finer cutting surface. Finer grits give you a finer and finer cutting surface. You can also accomplish something like this with a knife steel. & #x200B; A kitchen knife sharpener is just carbide or ceramic in a predetermined v shape. You don't have any control over the depth of the v and the final sharpness of the blade. The end result is often mildly sharp, but rough, and doesn't hold an edge as long. It's fine for basic stuff, but is rough on your knife and won't get you anywhere near razor sharp. A razor sharp knife is a joy in the kitchen. & #x200B; Think of it like grinding wood with an angle grinder and sanding it with fine sandpaper. You can get the basic shape with an angle grinder, but the sander will make it smooth and give you more control over the shape.",
"It's like the difference between taking your Ferrari to get a car wash at the automated car wash machine at your local gas station, vs., going to get it hand washed and detailed by professionals. I'll give a better explanation when I get home and hooked up to a battery charger. But I'll tell you this: as a professional cook, the first rule to good knife skills is knowing how to care for your blades, whether they're cheap Walmart knives, or fancy/expensive Japanese steel. Also, if it takes you two hours to sharpen one knife by hand, you're doing it completely wrong. But seriously though, sharpening knives by hand has a zen like, thing to it. It really is relaxing.",
"A whetstone is like using a nail file to smoothly finish your nails - a cheap sharpener is more like using scissors to scrape nails smoother."
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ctdufm | Why can't you create your own ISP to access the internet? | Technology | explainlikeimfive | {
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"So you want to become an ISP. First you need your own network that your customers can connect to. If you just want to be your own customer that's fine, this just reduces the complexity of the network to one node and all you really need is a network interface and some cable. But now this cable has to reach the internet. If you want to be your own ISP you will have to find a way to connect this to the internet yourself. You would have to lay your own cables or buy access to existing cables to the nearest node. You may have to pay for traffic to that node, you will have to adhere to some standards of networking and so on. So while it is certainly possible to become your own ISP it is neither easy nor cheap.",
"if you can get past the regulatory hurdles then you'd need a lot of money to dig and run cable all over the place plus buying bandwidth from a tier 1 or tier 2 provider. you can do it if you wanna spend a lot of money.",
"You actually can. However whoever you are getting your internet from as an ISP has to allow you to do so. The main limit however is the infrastructure involved. Its not like you can use Comcast's cable lines yourself. There are a number of successfully small scale ISPs that use wireless access though.",
"Imagine you live in a dystopian future where all roads have been privatized and turned into toll roads. If you want to drive from your house to your friend's house you first need access to the road that is front of your house. The owner of that road would be your 'Street Service Provider'-- for example, comcast. In many areas there is only one choice of street provider. In some areas, there might also be a second street provider behind your house -- for example Verizon. Although there might be multiple routes to get from your house to your friend's house, you need permission from the road owners to drive on those roads. Of course, you do not have time to negotiate with every street owner on your behalf. So you just pay comcast a monthly fee and it is their job to make sure you can get everywhere. In your car, there is a GPS guidance system that tells you which route to take to get to your friend's house. Now, maybe comcast is doing a crappy job maintaining your street and it is full of potholes but they still want a ton of money per month. So you decide to start your own street service provider. How do you do that? One option is to build your own roads. That is clearly expensive because you must dig through other people's land, and also pay for the cost of building the road. But, you forge on anyway and build a single road directly to your friend's house. Now you have your own private road. It's great because there is never any traffic on it. But it is expensive, and only goes to their house. So, maybe instead you build a road that connects to a nearby highway. Of course, they charge you a monthly fee to be connected to their highway. But you can get to that highway fast. And once you are on that highway you can get anywhere. Of course, you still still paying a 'Street Service Fee' -- but now you are paying it to the highway provider instead of comcast. Alas, the route from that highway to another friend's house is very long. Plus that highway always has tons of traffic. So, to get to your other friend's house, more quickly, you need to connect to a different highway. So you build a second road. Now you can get a lot more places quickly. Of course, you have now built two very expensive private roads and you are still paying monthly street service fees. So you decide you want to allow your neighbors to use your roads for a small fee. But -- how do they get to your roads -- they only have comcast roads going to their house. If you are lucky, comcast will lease their roads to you and your neighbors can then use the comcast roads to get to your roads. But, maybe comcast doesn't want to lease their streets to you. Why lease them to you at a cheaper rate when everyone on that street would normally be paying comcast the full rate? Maybe, in some areas, the local government will force them to lease the roads to you. But in many places that is not the case. So if you want your neighbors to be able to use your roads then you would need to build your own set of roads to their houses. Of course, that is expensive and it will take a long time before you make your money back. Now, realizing that roads are expensive to build and require access to land -- you come up with a clever plan. Instead of building roads, you get a bunch of drones and you airlift their cars from their house to your roads. The drones aren't as reliable as roads, but they are cheaper to build and when someone new signs up, you can start offering drone service immediately. And, maybe instead of building a road to the nearby highways, you use a bigger (more expensive) drone which can carry more cars and has a longer range. Anyway -- that is basically what it is like to build your own ISP. Computers are like houses -- and like houses they are physically located all over the world. And internet connections are like roads. And like roads, those connections have to actually physically span the distance between places. Most places are not joined by a single road/connection. Instead of you get routed through a lot of different segments. Places where roads meet and you can get from one to another are called, Internet exchange points (IXPs or sometimes just IXs). Companies like comcast provide the connection to your house -- but if you want to connect to a machine that is not on the comcast network, then they must route your traffic through an IXP that will get your traffic to the right network. A good provider will have lots of good peering arrangements so that your traffic gets to the final destination quickly. A bad ISP will have few peering agreements and will route your traffic through highly congested routes. Internet routing is tiered -- so while comcast might connect to your house, they generally route a lot of traffic through backbones (highways) that they have to pay to access. So your ISP has one or more ISPs. No ISP or backbone can reach every machine on the Internet alone. It is only through money driven cooperation that traffic is able to flow from point A to point B. Since installing physical connections to every house is expensive, some ISP startups have tried to use wireless connections instead. Wireless connections are not as reliable as a physical connection, but you don't have to buy any land or install any lines. You just need to add a wireless access point at the customers house. Since the range on those devices is limited, you may not be able to get away with just have a single centralized point that they connect to -- you might have to have intermediate connecting points installed all over town. And, to get the best possible range, you want those connection points installed up high in the air. That means you need to lease space on top of highrise buildings, radio towers, etc. In short -- you can start an ISP. But, the costs of doing it are so high that you need to be able to build a large subscriber base to pay for the costs of setting up the equipment. Also, earlier I suggested the comcast has to pay for access to the IXPs. But that is not always true -- there are some free IXPs. Also, since comcast needs to connect to a lot of verizon subscribers and verizon needs to connect to a lot of comcast customers -- they might opt to peer with each other without compensation. Peering is mutually beneficial, but since it also requires buildings and equipment and staff, it incurs costs that have to be paid for somehow. So there a variety of different ways peering is funded. There are a few ways that micro ISPs could work. In some high rises, the condo association becomes their own ISP. The condo association pays a lot of money to get a very high speed internet connection run to the building. Then the costs are shared by the people in the condo association. It is generally much cheaper to get a high speed data line at a data center than it is to get one at your home. So, if you wanted to start a neighborhood ISP you might look at a wireless solution. Your neighbors would all have wireless connections to your house. And at your house you would have a microwave link to a nearby data center. Then in the data center you are connected to the rest of the Internet. But.. your other neighbors might complain about the unsightly radio tower installed behind your house."
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cte9v6 | How do these advertisements work, when they are put on one side of the glass and you can see them from that side, but not from the other side? | I hope I described it well enough, but I'm thinking of those big advertisements on the sides of buses and fast food places and stuff, when the ad is on one side but from the inside it looks like the glass is clear and nothing is there. | Technology | explainlikeimfive | {
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"Oh I know what your talking about the factory I work at has those, interesting thing you can't see them from far away either under certain light settings. It's actually called perforated window vinyl and basically it works like this they pop a bunch of holes in it which actually removes a significant amount of the material to help you see through it, as far as I'm aware the most holes you can get is 40% and it still look good from the outside, our eyes naturally focus on a bright, well-lit surface rather than on the holes and the relative darkness of whatever is behind the surface. The inner side of perforated vinyl, however, is dark colored. Here the eye naturally focuses through the dark vinyl to the light and motion outside the window. Because of this, people inside a store, home or automobile see through the back of the sign to the world outside. Basically it's an optical illusion when you think about it, also at night if there's a light right on it, it may be hard to see it even from outside"
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ctfb5z | How the hell do I secure myself from data leaks? | I recently found out about all the leaks and stuff and that apparently my email was leaked and I just freaked out. So of course I started google the shit out of it and there's so many words and things I have no clue what they mean or what it is for so it was kind of a torture for me. I don't do shady stuff on my pc, but I just want to protect myself from any kind of data leaks. It's even uncomfortable to think about that some kind of stranger might be able to see all my info and etc. | Technology | explainlikeimfive | {
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"Unless their plan is to rob you or post your nudes on Facebook I wouldn't worry so much about it. There isn't a hacker on earth who gives a shit about your search history. Get a VPN if you're paranoid but still relax.."
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ctgzah | Drive partitions. Is it like splitting one drive into two smaller drives? If so, then when is this useful? | Technology | explainlikeimfive | {
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"I usually use it to separate my own data from Windows. That way when I inevitably destroy windows, i can reformat just one partition without having to worry about recovering data. The main use and need is that partitions can be formatted differently. For example UEFI bootloaders need a specially formatted partition to be recognized, but operating systems will use a different partition format. Also if you are dual booting it will let you use two different operating systems on the same drive.",
"Drive partitions create smaller logical drives out of bigger physical drives. Useful reasons are: limiting permissions to some stuff, having a boot-recovery segment, storing data and OS/apps separately so an OS install doesn't wipe your data."
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ctil9d | why are sub pixels on monitors and TVs different shapes? | I was watching a video by the slo mo guys and i was wondering why the pixels when they showed the LED and OLED TVs had different shapes. This image explains it more: [ URL_0 ]( URL_0 ) The red sub pixel is a sharp rectangle where as the green and blue sub pixels are a sort of smooth-rounded-cut-in-half square. Are they like this because it gives different effects or is it because it has no effect at all and was easier to make it like this? is so why is the red different to the green and blue sub pixels? | Technology | explainlikeimfive | {
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"text": [
"That's actually a super weird arrangement. Normally green is actually smaller because the human eye is more sensitive to green light."
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ctj3vp | How does Google Maps know the exact coordinates of roads? Where does it get this data? | Technology | explainlikeimfive | {
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"text": [
"Well, the United States government publishes thousands of maps every year. There is also publicly available satellite photos which can be cross referenced with those published maps. And they also have the Google Street View vehicles, which use GPS and are attempting to drive down every public street in the entire country. So between those three things, they can get a pretty accurate map system going."
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ctktz0 | DVI-D vs VGA cables | I got a new monitor off my dad and he wants to use an adapter because my pc has no VGA ports (that work) what’s the difference between VGA and DVI-D? | Technology | explainlikeimfive | {
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"VGA is analog-only and carry only a video signal. DVI-**D** cables are digital only and carry only a video signal. DVI-**I** cables both carry a DVI video signal, AND a VGA analog signal for backwards compatability, allowing you to use passive DVI-I to VGA adapters or cables. The If you look at the port/cable, DVI ports are long with a bunch of pins on one side, and a flat pin on the other. If that flat pin is surrounded by 4 normal pins, that's a DVI-I port as those pins carry the analog signal. Otherwise, it's a DVI-D port. If you're trying to accomplish connecting a computer with a DVI-**I** port to a VGA monitor, you can either use a DVI-I to VGA adapter and connect that to a VGA cable, or get a DVI-I to VGA cable. If the video card on the computer only has a DVI-D port, you will need to get an active adapter that converts the digital video signal to an analog signal. These adapters are also available for other ports like HDMI and DisplayPort."
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ctnoj2 | how do wireless chargers work? | Technology | explainlikeimfive | {
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"text": [
"Electrons moving through a coil create an electromagnetic field. Conversely, if you put a coil in an electromagnetic field, you can get electrons to move. The charger has a coil that creates an electromagnetic field, and your phone has a coil that picks up the electromagnetic field and moves electrons to charge your phone."
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cto8iq | Why do computer screen pixels change colour when pressed on? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"LCDs are liquid crystal displays. They rely on liquid crystal in order to attain the dimming of pixels with electricity. When you push on them, the liquid is somewhat displaced, and so the area around your finger does not get as dark as it is meant to."
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ctpryl | how is google satellite view so detailed in certain areas especially when it comes to 3D? | Google satellite view doesn't cover every area so in some it looks like a bad photo where 3D isn't even possible but for some more famous areas and cities, it looks literally like a mock up of the area with easily visible windows (if you pick 3D view) and other details. | Technology | explainlikeimfive | {
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"text": [
"Not all of Google Maps Satellite view was taken from satellites. For big cities and stuff Google will pay a company to fly overhead in a plane (or helicoptor?) and take much higher resolution pictures. Then they stitch the pictures together to make a single continuous picture. For the 3d view, Google used to (still does?) ask people to draw a box around buildings and tell how tall it was (eg: 3 stories) and it would turn it into a boxy 3d version from that data and the existing photos. That's all I know though."
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ctqu0s | How are Raster images and Vector images different? | If raster uses pixels and vector uses "math", aren't vector images also using pixels, because the screen displays in pixels? | Technology | explainlikeimfive | {
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"text": [
"For a raster image like JPEG or BMP there is a fixed number of pixels and the image contains details on the value for each pixel. JPEG requires a bit more math to get to that value and BMP just straight has the pixel by pixel values, but both of them are for a very fixed number of pixels. If you expand the image you'll just get a blurry image with no attempt at upscaling. If you were to look into a vector graphics file like SVG, you wouldn't find data for a fixed number of pixels. An SVG doesn't store the image, it stores instructions on how to draw the image. Vector graphics store vectors and include details on what angle a line takes, how long it is, where it is. Text is stored as text so if you zoom in on the letter A you don't get a blurry shape like you would in JPEG, you have a crisp letter A all the way down. In the end, it is all rasterized to put on your screen but a vector image can be zoomed in on super close with no loss of quality unlike a raster image.",
"Others have covered the difference between vector and raster, however it's worthwhile to add that there *are* vector displays. Such displays are based on CRT technology rather than LCD technology and involve sweeping the gun from point-to-point rather than across-and-down in a grid fashion. However, both color and solid fill are inherently raster operations that don't function well (if at all) on such displays - all you tend to get are monochrome wireframe drawings."
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ctt49k | Programming Functions and why are they so special | I'm still trying to wrap my ahead around this concept. I've done basic maths, so I know that f(x) = x is like a function, but I can't find an intuitive way of explaining why some functions don't have to return values. In addition, what separates functions from just lines of code? | Technology | explainlikeimfive | {
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"You use functions to break up the code into pieces. Each function should perform one task, if it’s more than that, it can be broken up into even more functions (that’s sort of what abstraction is). Some functions may need to return a value, but some may not at all. If you have a function that just deletes a file, you don’t need to return anything from it. But if you have a function that adds two numbers, you need to return the result.",
"A function in a computer is more like a task. You tell the computer what (work) it should do. A function can have input or output but they don't need to. I give you a few examples. First lets define a few variable (that is reserved memory and it interpreted in a certain way) var1, var2 and var3. Example1 you can define a function that has no input nor output. The work it should do is to calculate var1+var2 and write the result into var3. You can manipulate var1 and var2 outside of that function and then call it to do the addition. Calling the function in pseudo code: var1=4 var2=6 function1(); // var3=10 Example2 your function now takes 2 inputs input1 and input2, but no output. By your definition it should calculate input1+input2 and then write the result into var3. You can now take any variables (e.g. var1 and var2) and put them into the function, it will always write the result into var3 though. var1=4 var2=6 function2(var1, var2); // var3=10 Example3 your function now only creates an output. Internally It will calculate input1+input2 and write the result into the output. var1=4 var2=6 var3 = function3(); // var3=10 Example4 your function now has 2 inputs and will write the result into the output. var1=4 var2=6 var3 = function4(var1, var2); // var3=10 Example5 your function takes 3 inputs; it will calculate input1+input2 and write the result into input3. For this example it will interpret the inputs 1 and 2 as numbers but the third input will be interpreted as the location (in the memory or \"adress\") where it should put the results in. var1=4 var2=6 function5(var1, var2, var3); // var3=10 All 5 kinds of function can be used for different kind of work."
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ctvvc5 | How youtube channels for kids make money? | Technology | explainlikeimfive | {
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"text": [
"Ad Revenue. Little kids are more likely to watch the same video over and over again which adds up quick. And since these channels have nothing that would anger advertisers they aren't at as high of risk of demonetization as other channels who target older demographics.",
"You’d be surprised how much kids influence their parents to buy things. Even if they don’t buy it out of the blue, parents might buy it for a birthday or holiday gift for their kids. The advertisers do make money on their product, so they continue to pay the channel to advertise their product. That’s how the youtube channel makes it’s money."
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ctwch1 | The difference between computer programming, computer engineering, software engineering, computer science, electrical engineering, and IT, and any overlapping between any/all of them. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"IT is the overarching term for all that stuff. Computer programming is creating the programs that your computer uses. Computer engineering is building the hardware that your computer uses. Software engineering is studying and building new software for use in a wide variety of applications Electrical engineering is the study of and construction of electrical networks (these don't need computers can just be like lighting). You forgot network engineering, which is designed, building, and maintaining the networks that allow computers to communicate with each other."
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ctx4qg | How do email services know which emails should be filtered as spam and which ones are not? | I was thinking about this while applying for jobs. I noticed that autogenerated emails from companies came through to my inbox but the ones from spammy fake companies offering jobs didn't. | Technology | explainlikeimfive | {
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"text": [
"There are a variety of systems to handle this. Some systems look for things on the email. The subject, the body. Look for things like generated from emails, font changing, etc. Another system looks at the email process trail. How did it get delivered into the mail system. Who the sender is. Does the domain name match the sender? Does the domain match the trail? Is the domain marked on the 40 or so blacklists? And also did anyone else in the world mark this email or similar email pattern as spam?"
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ctz8zj | How do they re-release full HD movies of older movies like 1985's Back to the Future, that are crystal clear? | Technology | explainlikeimfive | {
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"Older movies were shot on film. Film doesn't have a \"resolution\" in the same sense as digitally shot movies, because it isn't stored as pixels. Film is just layers of chemicals on a sheet of celluloid (or nowadays some other plastic), and those chemicals change colour when exposed to light. That means a physical image of each frame is stored when the movie is shot. When they digitise an old movie in HD they just take a higher resolution digital scan of the image from each frame of film. The quality of the physical image stored on film is so high that you still see an improvement in image when scanning up to 4K/8K resolutions, possibly even higher. Edit: removed \"filmed on film\". It's hard to talk about film without using the word film to mean \"cinema\" or \"shoot\" or \"movie\" because that word can mean basically anything. Edit 2: To address the most common misconception I'm getting in replies to this comment: no, modern HD/4K etc scans and remasters aren't \"higher resolution than the originals\", they are just higher resolution than the old, low res digitised versions. So your 4K Star Wars remaster isn't going to be higher resolution than the original film version shown in cinemas, but it *will* be higher resolution (and closer to the original in terms of resolution) than the old DVD version you have from back in 2004. Often the HD remastering also involves other elements like removing defects in the film, sharpening images, correcting colour, and updating VFX to suit the new resolution, which may qualify as \"improvements\" depending on how they're done and what you think of them.",
"Older movies were shot on film, meant for a big theater screen, they were always HD. It’s when they are converted to digital they start to lose quality. As we get more advanced technology we will get closer to having the full resolution of the movie available to us at home.",
"Everybody is talking about celluloid film and resolution compared to digital but I haven't seen anyone mention yet two other factors that influence picture quality of old films - Film ISO and quality of lens. When shooting dark scenes with film, you have to use a film that is more sensitive and can react with less light but to accomplish this the film needs a bigger grain. This results in an image that is much grainier and there is some loss in sharpness/detail because of that. Also, lenses influence the quality of the light hitting the film and can introduce other flaws to the final image quality like softness, chromatic aberration, blurriness in the corners etc. For some of those flaws, scanning at higher resolution doesn't always result in a better image unless they scans go through some heavy post-processing which may not always improve the image. Directors & cinematographers had to work with the tools (and budgets) they had and it's quite amazing what was accomplished with film over the past several decades. Also, one additional thing, for xHD digital releases it depends on the print that's being digitized. If the studios can scan from the original work print which is one generation from the negative then they will get the best possible results. If they have to resort to 2nd or 3rd generation copy, the quality starts dropping. Like a photocopy of a photocopy, each resulting in a loss of detail, dynamic range, and overall quality. Analog is a pain in the ass in that sense.",
"[ URL_0 ]( URL_0 ) & #x200B; This isn't for Back to the Future but its probably a similar process. Fascinating piece.",
"They use the DeLorean to travel back in time with a modern high resolution camera. They simply film the original scenes as they occurred in 1985, bring the new digitally recorded version back to modern day, and re-release the movie.",
"Older movies were shot at a higher visual quality than what was possible to distribute at the time. For example, broadcast, VHS, and even DVD technologies were not capable of doing justice to the quality of the original content, so all releases of Back to the Future using those distribution technologies sacrificed some of that original quality. Now that full HD distribution is easily accessible, there's an incentive to go back to these high quality originals and rerelease them in better quality than could be distributed before.",
"A lot of people are pointing out that old films are analog (as opposed to digital) so they have no resolution. Technically, this is true, but it is not the whole story. VHS tapes were also analog, not digital: analog doesn’t mean lossless. Edit; For those of you too young to remember, VHS tapes are very low quality. Analog media has different loss mechanisms than digitized media. Just the act of digitizing media will guarantee some amount of loss, depending on how it’s digitized (e.g. 1080, or 4K). The reason that we can get very high quality duplicates of old movies is that the original films for those movies are actually very high quality, and we now have the technology to view them with very little error from sources of loss like dust.",
"Film has a higher resolution that digital content we know and love. So the information to make a 1080p or 4k version is in the original film."
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cu50ac | What changes when a popular from 40-60 years ago when it is "digitally remastered"? | Sometimes I notice that there are two different versions of the same song online, except one of them just says "digitally remastered in 20xx". I never hear any differences in the songs. Anyone? | Technology | explainlikeimfive | {
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"One thing they can do is remove any unwanted noise, clicks, hiss etc from the track, boost certain frequencies say to give it more bass, if they have access to the original multitracks they could mix it differently. Some info here [ URL_0 ]( URL_0 )"
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cu6rn2 | How do sound-canceling earmuffs cancel out sound? | Technology | explainlikeimfive | {
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"The earphones have a microphone and hears the outside sound, and plays a reversed version into your ear to “cancel out” the outside noise. Ingenius really. A bit like two waves in an ocean hitting each out and eliminating both"
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cu7vp6 | Why do black lines appear and move around when you zoom in on a picture of a television screen? | Technology | explainlikeimfive | {
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"To put it simply : because the grid of the pixels in your TV is not aligned with the grid of pixels of your camera sensor. For it to happen you would need to have exactly the same number of pixels on both devices and have them perfectly ligned up by taking into account lense distorsion and field of view or your camera. That's not likely to happen even if you tried your best. Because of that misalignment you see dark patterns where pixels from your camera caught the spaces between two pixels from your TV. That's if we are talking about a modern flat screen TV. If you are talking about an old TV then what you are seeing is the picture on the screen being refreshed at a different rate than your camera, making the transition between two frames appear either as a moving or fixed line, a dark patch or a blinking black image.",
"Please remind me when someone answers this. I always thought I was imagining it but you’ve seen it too so"
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cudpkd | I don't understand how governments can switch off the internet-connection of entire regions. | Technology | explainlikeimfive | {
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"We sometimes think of the Internet as invisible and all around us, but in the end it's carried by cables. All the wi-fi hubs and cell towers in a region are connected to a network of cables that eventually hook up to a small number of \"backbone\" cables that link regions together and tie the country to its neighbors. Most governments either own the backbone network, or can apply pressure to the people who do. Shut it down, and *most* of a country's internet goes away. Not quite all of it, though. Satellites, privately-owned cables, and long-distance radio aren't used very much for ordinary Internet communications: the first two are too expensive, the last one is too slow. But it's possible for ordinary citizens to use these to set up impromptu networks to get around the government censors. They'll never match the power of the full Internet, but they can provide a little bit of communication.",
"The internet is essentially a network of networks. Countries who's government controls the overall connections leading out of that country can sever that connection allowing people to only have access to servers within the country. Lets say you have 3 countries, A, B, and C. Each of them connects to each other, but country B's government controls all the wires that come into the country (the wires from A and C). If B wants to, they can disconnect from A and C. This doesn't affect A and C as they can still talk to each other, but people in B can now only connect to other people (and servers) in B. A good example of this is the US government's DODIN (DoD Information Network). It connects to the public internet *only* through specific paths owned by DISA. If DISA (or the government as a whole) wants to disconnect from the public internet all they need to do is block traffic trying to go in or out over those paths to the public internet. The rest of the network continues to function as normal, but the users are unable to access the public internet. EDIT: So why can't affect people connect directly to a server with the IP? Because in this situation (where the government blocks traffic into/out of the country) there is no connection between the affected people and the server they are attempting to connect to.",
"Totalitarian governments simply mandate that the ISP's must block traffic that they (The government) deem illegal or unwanted. If the IP address of the site you're trying to visit is on the restricted list, then that traffic will be blocked. In order to bypass this, you must use a VPN. This software basically uses a server that isn't blocked to access the website you want to visit, it then encrypts it and sends it to your computer. In other words, if you're in China and want to watch YouTube, you use a VPN that's located in Hong Kong, Taiwan or Japan, since YT isn't blocked there. VPN's can be blocked, all the ISP or censorship organization must do is block the IP's of the VPN servers. [Tor]( URL_0 ) is a similar tool that is much more difficult to block, as it uses normal computers to relay the traffic instead of dedicated servers."
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cuelas | How is an open-source software like OAuth generally more trusted/secure than non-open alternatives? Wouldn't the knowledge of the exact code make it easier to find and exploit flaws? | Technology | explainlikeimfive | {
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"The \"safety\" of open source software comes less from the \"harder to exploit\" part, and more from the fact that people know exactly what's happening. When you install some software from another person, you dont really know what exactly its programmed to do. Maybe it has some code that will slow down the program a bit every week until you upgrade it to a new version (like some programmer did with his excel spreadsheet for his work), maybe it will quietly collect data to send to the creator, or maybe it has a backdoor access. Deconstructing a program is difficult and time consuming. On other hand, open source means anyone can look at it and see exactly what it does. You know there's no hidden secrets or underwater stones there. It also means its easy for fixes or new additions to be made, because everyone knows exactly what they are working on.",
"Open source does make it easier to find explouts and therefore easier to correct them. A privately developed system with 10 experts working on it may be very good, but open source projects with 100s or 1000s of people working on, finding bugs and exploits, and correcting them turns out to be highly reliable, even if the contributors are not world class experts. There is also democratization in open source meaning a 14 year old's contributions can be taken as seriously (assuming they are good) as someone with 25 years professional experience. The quality is in the code, not the person writing it.",
"> Wouldn't the knowledge of the exact code make it easier to find and exploit flaws. Yes! And that's the point, if \"the villain\" can find the flaws so can \"the good guys\", and the good guys can then submit a fix to mend that flaw before a bad guy can use it for their advantage. Generally security by obscurity is a bad strategy: because while it makes it harder for people to find flaws it makes it harder for you to fix the flaws and might leave a gaping hole where you didn't remember to look that other people might notice. Worse still *other people* using your flawed software can't be sure if your software is safe because they can't check, they just have to trust your word for it. Proper security always assumes the opponent will use the best method they have against your system: there is nothing quite as comforting as a system that everyone knows the exact details of in every way, but can still do nothing to break it."
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cuelku | What instrument/equipment is disrupted by my active cellphone when flying on a modern airplane? | Technology | explainlikeimfive | {
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"None. Aircraft instrumentation may have been possibly affected by early cell phones and walkmans etc., **but now they're designed with cell frequencies and interference in mind. No, the reason why they want you to put your devices away is so you're _paying attention._ Paying attention to the safety briefing, paying attention as the airplane takes off. Otherwise you're the asshat who can't open the emergency exit because he didn't read the safety card, or noone can get past you in your seat because your tray table and Macbook pro are blocking the seat. edit: and as /u/hvarzan points out, cabin crew don't get paid enough to determine which devices DO vs. which ones don't, so the rule blankets ALL.",
"If you hold a cellphone up next to analog audio equipment (like a headphone cable using a standard jack), you'll occasionally hear intermittent buzzing. If you do this in a room without cell towers, it'll be louder and more obnoxious (since the cellphone will increase radio power in an attempt to get a signal). In theory, cellphones on an airplane could produce line interference in any of the aircraft wiring in a similar manner. It's very, very, very unlikely that this would happen with sufficient strength to cause any problems at all, especially with modern aircraft (which are designed with this interference in mind) and modern phones (which don't produce as much interference as older ones did). Think about it: if it were really dangerous, they wouldn't settle for just asking you nicely. They'd ban you having the devices. But they don't rescind the rule, because since it's the FAA, it has the force of law, and it's an easy way to deal with the fact that people's phones ringing/buzzing and people yapping away into them, in an environment as miserable as an aircraft, would lead to frequent outbreaks of violence.",
"To my knowledge, none. If was originally to stop interference in radio communications on the ground. I'm not a pilot or an engineer though, but I've read an article about it a while back.",
"On my recently flights they have you pack away things the size of a latptop or bigger in case there's an emergency during take off/landing. Other than that they actually promote their wifi and available services and even offer headphones for your cell phone.",
"See my contribution to a previous thread on this question: [here]( URL_0 )",
"I don't think it's actually dangerous anymore, just more that they keep the law because it would be wicked annoying otherwise. You know how annoying it is in a DMV or on a bus or other public place with someone talking loudly on a cell phone? Now imagine that, but on a cramped 10 hour flight with 300 passengers that are already pissed off because their flight was delayed by 3 hours."
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cuemxf | Why do windows computers take so long to shut down? | Technology | explainlikeimfive | {
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"Windows will gradually shut down all of the various background programs and update the registry during the normal shutdown procedure. Because Windows tends to have a lot of junk running at any given time, sometimes it takes a while. It definitely helps to have your OS installed on a solid state drive, though.",
"Do you mean specifically why windows takes longer than other operative systems to shut down, or do you want to know what it is doing while shutting down that is taking time?"
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cug9v7 | Why do MRIs take so long compared to other forms of radiation? | Technology | explainlikeimfive | {
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"I'm going to assume you are asking why it takes a long time versus other medical imaging techniques. An x-ray is just a picture, so it is done very quickly. A CT scan is basically just multiple x-rays done in sequence, so it's just a bunch of pictures, which is also pretty quick. An MRI is much more complex. First, you have a magnetic field line up the protons in your body. Then a radio wave is pulsed in, and antennas list for echoes from that. There's a built-in time for that, and each slice must be done, so it takes a while to go through them. And in each one of those slices, they usually have to run several pules, both to look for different echo patterns, and to vary the pulse that they send. There's also computational time to process that information, since it isn't a straightforward picture like an x-ray."
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cuj1ui | how does web domain hosting work? | I understand that if I want a website, I need to buy the domain from someone like URL_0 but where does godaddy get the domain from? Why can’t I create one on my own? | Technology | explainlikeimfive | {
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"If you create one on your own, you then have to convince everyone else in the world to listen to you and add your name to their DNS configuration. When you go through godaddy, they just hook you into the default tree that was created when the internet DNS name system was setup, and everyone can see it."
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cuja4k | What's the difference between URL_1 and URL_0 ? | In other words, when comparing two website pages functionally, whats the difference when the page name is before the website name vs. after the website name (with a slash)? | Technology | explainlikeimfive | {
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"The easiest way I can describe the difference would be... Say you have a department of a company. A /page would be equivalent to the department having an office within the headquarters building. A page. would be like them having a building on the headquarters campus. You have a lot more space for having subdirectories and organization with the extra space afforded by a page. implementation than a /page implementation.",
"When you go to URL_0 , your browser asks \"what's the IP address of URL_1 \". Then it connects to the server at that address and asks \"please give me the page located at /page\". When you go to page. URL_1 , the browser asks for the IP address of page. URL_1 , and then connects to that address and asks for the page \"/\". Functionally these might give the same result or different ones, depending on how the website is designed."
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cujmwz | An infrared image. | I saw this picture captured by the hubble space telescope [image]( URL_0 ) and it said that it was an infrared image. | Technology | explainlikeimfive | {
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"Not all kinds of light can be seen by your eyes, in fact the kinds of light we can see is a quite small part of the entire range. Light is a kind of electromagnetic radiation and the range which is visible goes between the color red (~~highest~~ lowest frequency we can see) and violet (the ~~lowest~~ highest frequency we can see). Light that is a bit lower frequency that we can see is called \"infrared\" and light of a bit higher frequency is \"ultraviolet\". That image was taken by a telescope that detects infrared light; of course if it was displayed to us in infrared we couldn't see anything so the range of infrared frequencies are shifted up to something we can see. This means the colors aren't accurate to reality but they are accurate relative to each other."
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cujv8e | How did Steven Hawking’s speech-generating machine work? How exactly did the machine express his thoughts? | Technology | explainlikeimfive | {
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"He had to very slowly type out what he wanted to say. It wasn’t a thought reading device, just a text-to-speech device. He didn’t have enough muscle control to speak properly himself, but even a small amount of voluntary movement can be used to control a device that allows you to select letters and words in order to get your message across. This process is generally very slow if you’re trying to communicate in real time rather than being in a controlled scenario with prepared questions and answers, though.",
"He used different technologies as his symptoms progressed. Later when his condition was relatively advanced, his program would scroll a pointer through columns of letters or words. An infrared light mounted on his head would detect twitches in his cheek. He'd twitch his cheek when the pointer was on the correct letter or word, and it would select it. He was further assisted by an autocomplete similar to many programs we use. Once he was finished, a speech synthesizer would read out the result. For many of his longer presentations this would be prepared in advance, as the process was fairly involved.",
"There was a small sensor which was activated by a muscle on his cheek/face. By activating the sensor he could ‘type’ on the machine to generate his speech.",
"To be clear his speech system didn't work in real time. Any time you hear him having a conversation with someone in what appears to be real time, it's been edited. He had to type letters out using a switch operated with his cheek, so as you can imagine, waiting for answers was a patient business."
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cuk68r | What is the role of an “engine” in videogame production? | Technology | explainlikeimfive | {
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"So, imagine you're a developer. You want to make a game, but you've never made one before. Where do you start? Game engines provide a pre-built scaffolding full of functionality that work out-of-the-box. Do you want Fog in your game? Unreal Engine has Atmospheric fog built in! ( URL_0 ) Rather than take the time to develop fog, which might take a developer weeks, you just use the functionality native in the engine. The same goes for various other concepts you might want to implement. Just the same, training developers is simpler if you use an engine. Has a developer previously worked on an Unreal Engine game? Great, they have a head start on your code-base and should only have to learn the things that you've done from scratch rather than your entire codebase.",
"You know how within Minecraft you can create all sorts of things. Build buildings, build train systems, and then using redstone, build all manner of interacting things, right up to full working computers, and using modern codeblocks, basically anything you like. For any of those, the 'engine' might be described as being Minecraft itself.",
"It's similar to using a word processor to write a novel. You could certainly write a novel with paper and pencil, but doing it with a word processor adds lots of nice features, like spell checking, and saving the novel to a file as you write it, and copy and pasting things around to easily make changes to it. You can make a videogame without using an engine, but it won't be nearly as easy, especially for any game that is not really simple. You have to build lots of little bits of it yourself, similar to building the ability to copy and paste text in a word processor. Most people who want to write novels have no interest in writing a bunch of software that allows you write novels. Most people who make games would rather use an engine, so that they have really sophisticated tools already available, and they can just focus on making the specific game."
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cuk8ci | How does a missile lock warning system work? | Same as the title. Just curious how military aircraft can detect that a missle from an enemy combatants aircraft has locked onto it before it's even fired when presumably the two are using completely different systems and completely independent of one another. | Technology | explainlikeimfive | {
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"Radar is radio, you can detect that someone (something) is using radar because they're transmitting radio; it's much like the detectors that detect police radar speed traps. And for the second part, a missile that's tracking a target will \"ping\" that target a lot more often, in order to keep up with its position changes. So it goes from one blip per second to like a machine-gun of blips per second. Lasers are detectable in the same way as radar. I don't know about heat- or visual- based (passive) detection, I imagine it's harder to detect by the aircraft being chased by the missile, but an [AWACS]( URL_0 ) flying above the area could keep track of all missiles and their movement, and automatically warn the combat aircraft below if any missile seems to be \"moving in their direction\".",
"Couple of different ways. The fire control radar on the launcher changes modes from a broad sweep to a narrow tracking system and different pulse frequency so it can \"zoom\" in on you and watch your movements on a faster scale and feed more accurate tracking data to the missile. Some missiles have their own onboard tracking radar, so once it is launched and starts painting you with its own radar, your threat warning gear can say \"Holy shit, missile launched!\" vs \"Uh-oh, we're being actively tracked\"."
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cukwp9 | What are the differences, plus strengths and weaknesses of different web browsers? Explorer, Chrome, Duckduckgo, Firefox, etc. | Technology | explainlikeimfive | {
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"All those browsers are made by different companies with different visions/goals. This means some may be outdated, slow or gather all your data. Do note that I am personally using Firefox for years now, so when describing major differences I will probably be biased/haven't used the browsers for too long and only know what I gathered from other users. Internet Explorer is really old and not developed anymore. This means it is missing many new features websites nowadays will try to use and in return often not display everything correctly. It also is slow. Chrome is made by Google. They got a lot of money - > Put a lot of money into developing it and currently chrome is the fastest browser*. Chrome also plans to prevent ad blocking in some ways in the near future (For example you will probably see Google ads, even with an ad blocker) Firefox is the second fastest browser after Chrome and is open source, meaning everyone can look at their code. This helps finding bugs/security exploits or even malicious code. Also Firefox doesn't save all your browsing data to analyse you. Duckduckgo is not a browser but an extension for different browsers AND a search engine replacing Google Search. Duckduckgo doesn't track your searches like Google Search does. All in all - for the love of god, don't use Internet Explorer. Otherwise choose as you please. *Found some number regarding speed in [this article]( URL_0 ), they say that while chrome is faster, it's only marginal and usually not noticeable.",
"Others already answered the question directly, but I want to add an important note. Internet Explorer should not be used for general web browsing. Even Microsoft considers it to be a \"compatibility solution\" at this point. Meaning that it should only be used to access old sites that had been made to work specifically with Internet Explorer and won't work on modern browsers. While there have been several emergency security patches made for IE, it still has many vulnerabilities. This is all in addition to the fact that it can't do many of things that modern web pages require and is generally a very slow and poor browsing experience. If you really need to use a Microsoft web browser, use Edge. More reading at the link below for those interested. [ URL_0 ]( URL_0 )"
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cum1zu | Why are virtually all file extensions only three characters long? | Technology | explainlikeimfive | {
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"Decades ago, computer storage was really expensive, and filenames do take up some space. Microsoft created a standard that allowed the use of names that were up to eight characters long and had extensions that were up to three characters long. [They called it 8.3,]( URL_0 ) and the three-digit extensions have stuck around.",
"This limitation comes from CP/M, an operating system that predates MS-DOS, which predates Microsoft Windows. CP/M uses 32 bytes for each file record in a directory, with 8 bytes for the filename and 3 bytes for the file’s type (extension), and the rest for other data such as file size. Two bytes were reserved for future use but never actually used, so we could have ended up with 5-character extensions (or 10.3 filenames) if not for some engineer’s whim. More details here: URL_0 And this limitation was around for so long - from the mid-‘70s through most of the ‘90s - that many of the most common file formats still in use today were established, so it’s conventional now."
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cuohw6 | Why do spacecraft and satellite components need to be assembled in a sterile environment? | Technology | explainlikeimfive | {
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"Most satellite components are not. Spacecraft that are likely to land on other planets are clean ed thoroughly to minimize the transfer of life to other bodies. In space with no atmospheric even oils from your skin can boil and condense to ruin lenses and other electronics equipment. Foreign object debris are one of the largest killers of satellites and to minimize this satellites are often assembled in clean rooms.",
"They don't need to be however the human race is trying to be very very careful about spreading earth-like life to other planets and moons. In our quest to find other kids out there it would be really frustrating to keep finding your own life form."
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cuojbh | Why does it matter which side is up or down when microwaving bagged popcorn? | Technology | explainlikeimfive | {
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"The popcorn bag has some metallic looking material built into one side of it that absorbs microwaves better. It basically acts as a microwave activated hot plate. Turning the bag upside down puts this heat source on top which is less effective for its use as a hot plate, and would shield the microwaves from reaching the popcorn directly. You popcorn will still pop but not as evenly or quickly.",
"Yes, for two reasons. 1. The bag has to unfold as it expands. If you put it upside down, it will have a harder time unfolding and run out of run. This could cause the bag to burst, allowing steam to escape and ending the popping process. 2. The bottom of the bag is reinforced to help the microwave heat the bag. You can feel it if you touch the bag before and after it's popped. The microwaves are supposed to hit it, heat the bag, which transfers more heat to the kernels and butter resting on it. If you turn it upside, that material blocks microwaves and doesn't transfer heat to the kernels, slowing the process.",
"Some caramel or butter flavoured ones have a thin sheet of butter or caramel that is on one side of the bag. When microwaved, it melts and coats the popcorn under it. If it's upside down, it just melts and forms a pool at the bottom of your bag.",
"The king of random had done a piece on this. Turns out, none of the instructions really mattered at all, you still get the popcorn tasting the same at the end",
"In my experience, it doesn't as long as the bag is unfolded. If it can't unfold, it can burn.",
"Protip: classic brown paper lunch bags can be used to microwave popcorn kernels adequately enough to be convenient and low budget, even though it might not pop as efficient. I've seen different techniques used before but I kept mine extremely simple because I'm lazy. I can't remember exactly but I used like a half cup of kernels or so and dumped them in, then just folded the top opening of the bag over itself a few times in a thin manner. I've used scotch tape before and even once used a staple (no it didn't spark, might be too small, at least it didn't react in my microwave) then I would just nuke on high for a few minutes and monitor like a normal bag of popcorn. The benefit is you get no added ingredients, chemicals etc and then you can just add what you want. I've even stuck a pat of butter in the bag before to try get it flavored but it just ended up being a mess so adding stuff after just makes more sense.",
"Cus it's folded in three parts.. the folds have to be facing up so they can open when it starts to warm up",
"The butter is put in the bag on top of the kernels. Turn the bag over and the butter would be on the bottom. Not very effective to have only some of the kernels coated in butter but others not.",
"Because when the popcorn is upside down it inverts the operation. That turns the explosion Popcorn/1 into and implosion 1/popcorn. This enacts a black hole that sucks in your popcorn. If you have a microwave over 1000 watts,be careful. You can suck in the whole kitchen leaving you with nowhere to get snacks for your movie. As labeled, caution should be exercised.",
"Popcorn bags are a scam - buy popcorn kernels in the bulk section of your grocery store, put a single layer of them at the base of a big pot with some oil (coconut oil adds a nice touch!) and put on low-medium heat for 5 minutes. Somehow I went the first 25 years of my life believing you had to use one of those Jiffy pop or microwave bags to get popcorn.. boy was I wrong !",
"Perfect popcorn that's easy: 3 tablespoons ghee/coconut oil in a covered pan on medium heat, add a few kernels. When one pops add 1/2 cup or so of kernels, shake them back & forth to get the heated oil coated. When the popping slows, turn off the heat, move the lid about a half an inch to breathe. Add some sea salt & enjoy."
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cus4cy | What's the difference between a SQL and a NoSQL database? | All the google results and youtube tutorials give me a full 20-40 min lecture or a tutorial on how to code on MySQL or MongoDB, but I have no clue what they're saying (I have zero background knowledge in comp sci). & #x200B; What exactly is the difference between SQL and NoSQL database? When should I use SQL over NoSQL and vice versa? | Technology | explainlikeimfive | {
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"SQL Databases are designed as a series of tables that are related to each other. They usually have a fairly rigid structure. The \"S\" in SQL is for \"Structured\". NoSQL databases are usually thought of as a series of documents that have a much looser structure and relationship to each other."
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cuvpxh | Is cell phone cloning a real thing? Saw it in a tv show. If it's possible, how does work? | Technology | explainlikeimfive | {
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"Cloning a phone is possible, but it will not allow you to listen in on the cloned phone. Best you’ll be able to do is sometimes get the calls meant for the cloned phone. Until the phone company detects the cloning and shuts off the whole account."
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cuyjkt | How are mid air collisions avoided? How likely is it to occur in our days and how responsible are ground based personnel to keep flights safe? | Just watched a series where someone who was working in flight control, gave instructions to 2 flights and made them both collide, and was wondering how possible it is. | Technology | explainlikeimfive | {
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"Transport airplanes have a system called TCAS. ~~Terminal~~ Traffic Collision Avoidance System. It sends out a signal that pings any planes nearby. It warns you if there's a plane nearby. If two planes get too close, it will [tell one to climb and the other to descend]( URL_0 ).",
"Aircraft maintenance student here - anyone else feel free to chime in: To put it simply, aircraft use a set of instruments that will alert the pilots of any oncoming aircraft. Aircraft control towers also monitor this with their own set of instruments and Rada allowing them to direct traffic accordingly. From what I've read in my texts the odds of a collision happening are slim to none."
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cuz1br | Why do browsers such as Chrome and Edge use such a seemingly large amount of memory? | Technology | explainlikeimfive | {
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"Unused RAM is wasted RAM If Chrome uses 500 MB of RAM and pages take a half second to load it's alright But if you've got 8 GB of RAM and it gobbles up 2GB precaching pages so they now only take a quarter second to load then you're happier. The increased RAM usage doesn't really matter. If a real program comes along and asks for memory to run in then it'll get dibs and chrome will back down, but a gig of RAM sitting there empty is doing nothing but consuming power, might as well use it!",
"Web developers like making things look pretty, and having ads and side-bars. It means that each page has a bunch of pictures and videos on it. You've got 5 tabs open, each with all of that data loaded separately. And the browsers keep some of that in memory until closed, cuz people like their back buttons to feel responsive. It all adds up pretty quick.",
"Remember, most modern websites these days are like standalone applications. (e.g. Google docs is like having Word open, Gmail is like an email application, YouTube like a video player etc) Multiple browser tabs ≈ Multiple applications running at once, which can easily eat up tonnes or RAM",
"Chrome added *subframes* about a year ago, in order to help protect users from some [pretty bad exploits, including Spectre.]( URL_0 ) Essentially, any site that uses a function called an *iframe* will have the frame's content isolated from the original tab, providing enhanced security. Each subframe runs as it's own process, taking up 15 - 20 MB each. Menu... More Tools... Task Manager will show you the subframes running in Chrome. If you have a lot of subframes running, you can close Chrome and re-start it to \"start fresh.\" Subframes only open when you visit a site that uses iframes, but once open, the subframe stays open until you close it using Task Manager, or re-start Chrome."
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cuzscf | that my monitor supports up to 720p however there is difference in video quality between 1080p and 720p on youtube. How is this possible? | Technology | explainlikeimfive | {
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"1080p is generally higher quality and so any imperfections from compression would be hidden by starting with a better quality image overall and scaling it down. The size of a compressed frame (measured in bits or bytes as you please) is somewhat proportional to the quality of the image and the resolution doesn't matter as much as you might think. There's more bits of data in a single frame at 1080p and scaling it down to 720p largely preserves the fundamental quality of compression. But there's one other explanation most people don't know about: the videos on youtube (and indeed most TV feeds) is compressed using a chroma subsampling method known as 4:2:0. What this means it that for every 2x2 block of pixels there is only a single colour value shared by all 4 pixels and the relative brightness (black to maximum colour brightness) is what's different between all 4 pixels. [Wikipedia has pictures that help explain it.]( URL_0 ). So when you go up to 1080p, there's more colour details available and even with stretching the colours are a bit more detailed since the 2x2 blocks are shrunk.",
"resolution isn't all information you need to know about a video to judge it's quality. it also depends on the quality of compression. the compression algorithem is tuned for a certain bitrate at each resolution setting on youtube. the lower bitrate it has, the less info it has to put in each frame. so below a certain bitrate, there isn't enough info to recreate the images perfectly, so it becomes blurrier. what you're experiencing is typical for youtube, as they have quite low bitrates for their resolutions. you'll probably still notice a difference when you switch to 4k"
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cv1lhm | How do radar machines time light in order to calculate distance if light is hundreds of times faster than electricity? | If light travels faster than electricity, how do radar devices switch between broadcasting and receiving and manage to accurately determine an objects distance based on the echo of a radio wave. One would think the radio echo would be long gone before the device ever had a chance fully switch over and to detect it coming back | Technology | explainlikeimfive | {
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"Because it isn't. Electricity in a wire travels at 30 to 90 percent of the speed of light. So your premise is, fortunately, incorrect.",
"Much older systems would separate the emitter and receiver, but newer versions just integrate both functions into the same unit. Still, there is no switching; as you say that would be impractical. Rather it is always \"listening\" passively, or listening for returns from the emitting portion."
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cv2udy | Why does 1080p content on a 4K screen not look bad like SD content does on a 1080p screen? Isn’t it being upscale the same way? | *upscaleD. To hell with autocorrect. | Technology | explainlikeimfive | {
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"Old content was really really low definition but that was alright because of how it was viewed To fit SD content on a 1080p screen each pixel is 2.25 pixels wide, but more importantly you're generally watching it much larger or much closer than it was meant to be. Watching 480p on a 20\" TV from 8 feet away masks a lot of blur, but when you make it 55\" or watch it on a 20\" screen from just two feet away you can see all the pixels 1080p has enough pixels that your eyes don't have the resolution to spot higher resolutions at moderate ranges. Only if the screen is really big(large TV) or really close (cellphone) does it really show a clarity improvement",
"4k is exactly double the horizontal and double the vertical resolution of 1080p so one pixel becomes 4 pixels and you don't need to interpolate colors. Other resolutions below 1080p usually need upscaled by fractional amounts which will smear sharp lines when upscaling."
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cv679o | how does the thermal vision work? | Technology | explainlikeimfive | {
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"text": [
"Heat releases energy at a certain wave length. It's the exact same kind of wave length as light, we just can't see it with the naked eye. Infra red equipment can see this wavelength and reproduced or as a colour we can see."
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cv68fz | Why is it hard to simulate human mouse movement? | I read that Websites can know that you're not a bot by looking at the mouse movement. But why would it be hard to simulate that? | Technology | explainlikeimfive | {
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"Because an automated system to move and click through dialogs and pages would have to be able to scan and know where the targets to click on are. No human takes a perfectly straight line between targets, and certainly not with the same speed that a computer could react. You basically have to tell a computer to take a non-optimal path at a non-optimal speed, and to do so differently each time. It can't follow the same bezier curve, for example. Most humans also idle with their hand on the mouse and make it wiggle, whereas the computer won't move the cursor if it isn't given a reason to.",
"Honestly, it probably wouldn't be that hard to simulate human mouse movement using a neural network if you gather enough of data of mouse movement. But doing so is comparatively much more difficult and takes a whole lot more effort than having a script that says \"click this box, move mouse to this position, click,\" etc. But if someone really wanted to create an algorithm that could replicate human mouse movements, it could almost certainly be done. One pitfall with this is that using it on a very large scale would likely allow it to be detected by a sufficiently sophisticated bot detection program, since the mouse movement would have certain patterns that could be recognized on a large scale. But on a smaller scale it would work fine to bypass detection. Another problem is speed. Acting like a human requires you to go much slower than a computer is able to go, which isn't helpful when you're trying to create 10,000,000 bot accounts or something.",
"I can get it's hard to simulate a mouse, but how can't they simulate a touchscreen? I mean, it would only need to have a small delay to simulate reaction time and press in a random point of the square.",
"Human movement, on the small-scale, is pretty random. Lots of small little deviations, no straight line is perfect, we bias toward making arcs because of pivoting around our wrist, we are driving the mouse with five separate meat tubes that each are imperfectly coordinated, we are relying on abstracted hand eye coordination to guide the movement, our movements have momentum, etc. The sum of this is you get very random movement but that is very human-like in nature. Then compound this with some more random because this movement is being detected by an optical sensor that has its own noise rather than being a hard number. Computers are really bad at doing random, they are deterministic machines, its impossible to make them do anything truly random. You can make them approximate randomness, but ultimately its just a math equation with a seed value pulled from somewhere, its predictable if you know the input conditions. But more importantly a computer generating randomness off an equation to generate a number is very different to a humans randomness generated off mechanically moving a mouse around with our squishy meat bodies guided by our hunter-gatherer brains thats being recorded by an analogue sensor. There is just a different 'feel' to it even though both are random, and thats what mouse tracking is looking for, the absence of that human feel."
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cv7h3m | What's the difference in format if i post from a phone? | Technology | explainlikeimfive | {
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"text": [
"It's just easier to produce easier to read formatting on a computer than it is on a phone. It's not really that hard, but it definitely seems like a lot of mobile users don't take the time to have nicer formatting."
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cv8koi | How do creators of free apps/websites make money? | Technology | explainlikeimfive | {
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"Most likely they are either selling ad space in their app, companies pay for the advertisement, or they collect data about you and sell it on to companies that use it for marketing. As an example, you play a game on your phone, all of a sudden you start seeing ads about similar games here and there. Or you are using a shopping app to look for baby clothes, all of a sudden a lot of sites are showing you baby-related products. There are other reasons companies might want data on your shopping habits or what products you enjoy, for instance marketers might use it to gain insight into who the demographic is using a particular service or product in order to tailor a product more towards that group to get an edge over the competition. Remember: if you are using something for free, you are probably the product.",
"If something is free, you are the product. Selling ads spaces in their apps/websites or using your informations."
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cv8pys | how do big tech companies sell data? How do they turn users' data into profit & money? | How do they sell it and who buys it? | Technology | explainlikeimfive | {
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"Most of the \"big tech companies\" you're probably thinking of (Facebook, Google) don't sell the data directly. You can't really walk up to Facebook and say \"I want to buy 3 million email addresses and phone numbers, how much will that be?\" (Before someone chimes in to say that Facebook basically sold data in Cambridge Analytica or whatever, that's beside the point - giving people access to data for money is still not their primary business plan. If you think about it a little bit you'd realize that it would be a dumb business plan, because eventually you'd sell all your data, giving you nothing left to sell because it's all been leaked. Not to mention the immediate regulatory attention it would attract.) Instead what they do is sell ads, but use the information they have to sell better ads. For example, as an advertiser you could tell Facebook that you want an ad shown to \"10,000 people between the ages of 25-35 who are interested in Hiking in the US.\" Facebook will then show your ad to the users who it thinks matches your criteria, without necessarily revealing who those users are. Since targeted advertising like this is typically more effective than non-targeted advertising, advertisers continue spending money to run ads on Facebook and Google as opposed to other places that have less data on their users. You can try it yourself; it's pretty easy to run ads on Google and Facebook. You can spend a couple bucks to publish an ad that will get shown to some minuscule number of users.",
"They sell very targeted ads. If 10% of people are likely interested in your product, and you buy 100,000 ads at 1¢ a piece, you've spent $1,000 for 10,000 effective impressions. If instead a company says they can target your ad to only hit those 10%, but charge 5¢ each, you spend $500 for 10,000 effective impressions. You like this because you're not spending money advertising to people unlikely to buy your product. The advertiser likes it because they're generating 5 times the revenue per ad.",
"They sell your information to companies who want demographic information and in many cases like Google, Amazon, etc they get companies to pay them to present you with relevant ads based on what they know about you. Companies like Google, Facebook, etc make a profile of you and correlate that information for advertising/demographics. Example, let's say you make a widget and you want to market your widget on the internet. You believe your widget will sell among the male hockey fans between the ages of 18-35. But, you don't know how to target them. You can go to Google and they can strategically place those ads on your behalf. In return you pay Google for each impression/click you receive."
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cv8ziu | What's the"resolution" of film photography? | Technology | explainlikeimfive | {
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"There isn’t a specific “resolution.” It depends on two main physical characteristics of the film itself - the size of the film and the speed of the film - as well as the way that film is exposed. The first physical aspect is what format of film you’re using - there’s small, like a standard 35mm film that your average point-and-shoot camera would take; medium, which takes a range of film sizes (popularly 120mm); and large, which takes film sheets with dimensions of several inches. The second physical aspect is the speed of the film, or how long it takes for light to affect the film; the higher the speed, the lower the quality of the image. This speed references the density of the film’s grain- a higher speed has a larger grain, and thus the image is a lower quality, because a finer grain has the ability to capture more detail. This is probably the most direct similarity to digital photography and resolution, because the grains are essentially like pixels; more pixels = more details. The combination of film size and film speed essentially boils down to how many grains of film the image is being captured on - a large format film with a low speed will capture the most detail, because it has the most crystal to capture the details with. These physical factors are then combined with the way the film is shot - specifically, the length of exposure - because again, the longer the film is exposed to light, the more time that light has to affect the film in greater detail.",
"Film can have a higher 'resolution' or sharpness than you can effectively use. Now this isn't exactly for five-year-olds but [this]( URL_0 ) document has everything you need to know, and this part sort of answers your question: > Film Resolution defines the potential resolving power of a film; Kodak calls this sharpness. Resolution is determined using the MTF Curve, which is found in the film data sheets supplied by manufacturers. However, the MFT curve is measured using a sine wave bar chart printed directly on the film. The actual resolution of film is made on the film through a lens in a camera. > Based on the Resolving Power Equation(s) used by both Kodak and Fuji, the actual resolution of a “film-and-camera system” must be decreased by 30-80%, from native resolution. The greater the resolution of the film in a system, the greater the loss of the system resolution, for a specific lens with a given resolving power. This loss of system resolution is due to degradation of the image (1) exposed through a lens and (2) due to variables in film transport and film processing. > The MTF Curve of Kodachrome 200 (PKL) transparency film shows a native resolution of 50-lp/mm, (2540 ppi digital equivalent). Using the Fuji Resolving Power Equation, PKL shot through an excellent 35mm format lens (100 lp/mm lens) will have a final resolution of 33-lp/mm, with a digital equivalent resolution of 1962 ppi. This is a loss of 34% from the native MTF data, due to lens and film related issues."
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cvaiit | Why do older movies (not the silent movies which are intentionally sped up) look like they're fast paced when characters move across the screen? | Like Hard-Boiled by John woo for instance. The characters move quickly and recklessly across different points in the screen. The same is for other movies before 2000s. Is it cinematography or did the actors used to move really fast? | Technology | explainlikeimfive | {
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"John Woo has a unique style featuring very fast action and editing. This doesn’t reflect the pacing of all older movies. In fact, the pacing of film sped up in the late 60s, got even faster in the 80s thanks to MTV, and will get even faster thanks to YouTube. But a majority of movies made pre-2000s doesn’t have the signature frantic pacing of a John Woo film.",
"Action scenes are sped up to make it more spectacular. It's a signature technique used in Kung-Fu movies. [7. Sped-up film stock]( URL_0 ) In Hard-Boiled, John Woo not only uses speeding, but also a lot of slow-motion for dramatic impact.",
"Before commercials were 1/3 of television time, they had longer programs. To fit a 50 minute program in a 40 minute time block (more commercials in the same hour period) they cut it down significantly, plus speed it up. Comedy central is a huge offender in this, speeding up as much as 10%, cutting out silences (not like timing matters in comedy, right?) and cutting entire scenes just to max out commercial time.",
"In very old (really black and white, before sound and \"talking pictures\") film, it was partly due to a number of competing standards for film playback and recording, or a lack thereof. Another factor is an artifact of technology. Many cameras in early film did not have motors for exposing the film and were hand-wound with a crank. Thus the true frame rate was varied and depended on the steady hand movements of the cameraman. (In particularly amazing events of history one must watch in awe to consider how close a person had to stand and view these things and still keep a steady hand: such as the trenches of WWI, or Germany's early rocketry experiments.) Then these were played back via motor and showing the film at a constant framerate that was different than the recorded.",
"It does not have to be sped up to look sped up. The trick is in the camera. If recorded at 24fps you have 1/24th of a second to expose each frame. This is a lot of time and moving objects may get blurry but it also smooths out the motion. Normally I think they expose each frame at 50% duty cycle meaning the camera registers each frame for 1/48th of a second and keeps the shutter closed for the same length of time. Imagine a time graph where 'O' means shutter open and 'x' means closed. For 50% four frames would look like this: OOxx,OOxx,OOxx,OOxx. Kung fu movies use lower duty cycle, like 25% or less. This means that each frame is exposed for a shorter amount of time, the image is sharper (less time for the motion to blur it out) and there is a bigger jump in object position between frames making the video look sped up and the motion jittery. So for 25% it would look like this: OxxxOxxxOxxxOxxx. This is also why at 48fps, so 'soap opera' framerate everything looks smooth and slow because the camera would work like this: OxOxOxOx. Short exposure like in a kung fu movie making everything sharp but registered twice as often so less jeeky and more natural."
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cvava4 | How does my phone identify whether or not a wall adapter allows for fast charging? | Technology | explainlikeimfive | {
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"Older, passive, technology would use resistors or other means to alter resistance or voltage potential between pins of the USB connector - often the two data pins as they're not used when charging. Normally the resistance between those two pins should be fairly high, but if the phone measures a low resistance it might assume it is a certain type of compatible charger, and draw more current than was normally allowed over USB. The iPhone used the more complex voltage potentials instead and varied maximum current draw based on what combination of potentials it measured. e.g. the data negative pin at 1.8v and the data positive pin at 2.6v would cause it to draw the maximum amount of current, and thus charge faster. Newer, active, technology like Quallcom QuickCharge and the like actually communicate, with the phone 'asking' the charger whether it's compatible, requesting info on what charge voltages / maximum current draws are available, requesting a certain charge voltage and checking the response, etc. That's how they (relatively speaking) slowly ramp up charge voltage and (where applicable) current draw, and thus charge faster.",
"It all depends on the device. Long time ago it was about testing the connection. For example iPhones were checking if the charger had specific resistance between Data lines (normally adapters had them not connected), and refused to enable fast charging without it, limiting the current to standard 500mA. There were also chargers that set Data lines to specific voltages to show what current they are able to provide. Currently a charger is a USB device that talks to the phone and negotiates common capabilities."
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cvazhx | Who Owns "Unused" Internet Addresses? | Additionally, how do these companies/websites that sell domains obtained them? | Technology | explainlikeimfive | {
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"There are two types of addresses you might be talking about: IP addresses and DNS names. ICANN basically holds all the unassigned IP addresses, and manages Top Level Domains. The IP address part is relatively simple - IANA sells IP addresses in blocks, and the people that own those blocks assign them however. (It gets a bit more complicated than that, but it's not necessary to answer the question) Top level domains are the .com, .net, .uk part of an address. Every TLD is managed by a domain registrar, for example .com is managed by verisign. Countries get to choose who runs their TLD - tuvalu gets a not insignificant part of its government budget from verisign who also manages the .tv TLD. Domain registrars can sponsor new 'generic' top level domains. The reason ICANN is in charge of this, is because everyone agrees they are. This is something a little weird about the internet - there is no absolute authority. If ICANN got caught doing *seriously* dodgy dealing, a different organisation (e.g. the IETF) could very possibly become the new assigner of internet addresses.",
"TLDR: Specialist organizations like ARIN hold the rights to issue IPs, companies and organizations have to apply to ARIN to have IP space leased to them. But most companies get IPs via a 3rd party like an ISP. The right to issue IPs addresses belongs to organizations like ARIN (North America), RIPE (Europe), APNIC (Asia), AfriNIC (Africa), LACNIC (South America) Each of these organizations has blocks (subnets) of IP address space (both IPv4 and IPv6) which are assigned to their region. Companies and organizations petition to lease IP addresses from these organizations for their use. If they qualify they are then assigned a block of IP addresses which they can they use for their business in a kind of semi-permanent lease. Technically organizations are supposed to release IPs back when they are done with them but this rarely happens as IPs A. never stop being used, and B. getting IP addresses (particular in IPv4) is a difficult process so once you get them you don't want to give them up. (In the early days of the internet IP addresses were handed out wholesale and some companies like HP + Apple + AT & T were assigned ludicrous amounts of IPs which they continue to lease to this day. This contributed to the IPv4 internet essentially running out of IPs about a decade ago, hence the development of IPv6.) The vast majority of companies though don't bother with this process because it's both complicated, requires specialist hardware and technology to make work, and they are too small to qualify. Therefore they get IP addresses assigned to them from a 3rd party, which is usually an ISP. ISPs like AT & T, Comcast, Shaw cable, Bell Canada, etc lease large numbers of IPs from ARIN and issue them to customers as part of their internet service. The average company will have a small subdivided block of IPs assigned to them by an ISP as part of a contract for internet service. While your home will get a temporary IP assigned to your modem as part of the service. IPs that aren't in use at an ISP just float there waiting to be allocated. IP space in the global pool belong to the top-level organizations and basically aren't in use until allocated."
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cvc2f5 | Why does it take so long to search for a file stored on a computer compared to searching Google, which can produce billions of matching results in under a second? | Technology | explainlikeimfive | {
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"Google is an index. They don't just store copies of all webpages, they store an index of keywords. So if you search for \"bananas\", it will go to the bananas part of the index and return the results. Searching for files on your computer, there often isn't an index. Instead it has to go into every folder and every subfolder and look at the files in real time to find matches. This takes time. Now on many systems you can create an index to make searching faster, but there are trade-offs to having an index. Yes search results can be faster, but they can take up a LOT of storage space. It also takes CPU bandwidth to actively create those indexes. (I frequently find myself pausing windows indexing because it makes my computer run slow.) For google, their business is in having an index, and storage is part of that.",
"In short, indexing versus scanning. Scanning is when you have to go through every file/record to see if it matches your search. Indexing is when you pre-sort all your related files/records into groups, which are often nested, then you drill into those groups to find what you need more directly. A human example of scanning would be having a computer desktop covered in documents; To find what you're looking for you have to look at each file to determine if it's the one you want. Whereas, a human example of an index could be if instead that desktop simply had folders that grouped the files by type (say \"pictures\", \"spreadsheets\" and \"contacts\"), if you're only looking for images, you can save a lot of time by going directly to the \"pictures\" folder and ignore the \"spreadsheets\" and \"contacts\" folders because you know they don't contain any images. Of course, indexes can be represented in far more complex ways that group the same data in many different ways at once. For example, you might index an image by it's size (eg: large images, small images), colouring (eg: black & white, mostly red, mostly blue), the date it was taken (2017, 2018, 2019), etc. So then if you search for \"large black and white images from 2017\" the computer can eliminate results that don't appear in all 3 categories at once very quickly and only keep the ones that are.",
"Imagine you go through your house once a week and jot down every single item name, size, characteristics, color, and place. Then you memorize the notes you've taken. This is what google and your computer do. This means you can instantly recall every item when you need it. The cost is that it takes memory in your head and you need to do it again periodically since positions and items might move. Now imagine you didn't do this and need to find an item. You'd have to go through every single space and inspect every item. This is slow. Plus you're not committing this to memory when you do it. So 5 minutes later when you need to find a different item, you need to go through every item in your house again. Windows does do search indexing unless you turn it off, so searching for a file these days should take less time",
"Your computer has very little idea what is on it. When you tell it to search for something, it takes the word you search for and starts scanning the hard drive for every irrelevant match in sequential order. It is a time suck when you do search, but by not keeping a catalogue of every word in every file ahead of time it saves on space and keeps your computer from spending resources on something that will not be used before it has to scan everything again. Google has massive loads of processing power. Their whole job is to constantly scan websites cataloguing words that get searched for, remembering what people searched for and where they spent time before, and what websites are linked to those results. They have every search answered before you ask it, and then just spit out the list of anything close to what you searched for. The fact that it is finding thousands and millions of sites tells you that it is not being very discriminating on what it shows you, but ranks the top results based on how well the site owners have anticipated your search and forced their website to be the best match for what you are looking for.",
"Indexing keywords.... blah blah blah. The real reason is Google's infrastructure consists of 10's of millions of computers each with a chunk of RAM. Their index database essentially exists in RAM. An indexed search of RAM will always beat an indexed search of a hard drive.",
"Your computer is like having a filing cabinet, if you search for apples it has to go through all the files looking for Apples. Google has a filing cabinet just for Apples and shows you what’s in it straight away. (Non Eli5- if you have indexing on your computer or a fast ssd you essentially have this already but scaled down)",
"Nobody's mentioned parallelism. Sure there's an index, but also you can split the index amongst computers, so that each one only has a small part of the index to search. And each one can do that at the same time. It'd be like a room full of people each with just one page of a novel, someone shouts the word being searched for and then a few people stick their hands up and the shouter aggregates those results.",
"All the indexing information given here is good, but spreading that across thousands of servers is the key. ELI5: I give you 1000 random playing cards, and ask you to tell me how many aces there are. Then, I give 100 stacks of 10 cards to 100 different people and ask them the same question, then just add up their answers. We could even organize them so they'd know almost immediately how many aces they have. That's the original map reduce algorithm that drove Google's PageRank.",
"As everyone has said before, indexing. You can index your desktop as well though and it will be lightning fast. That’s what Apple’s Spotlight does to a limited extent.",
"On top of the indexing thing everyone already mentioned, and the millions of servers they have doing everything in parallel. It's worth pointing out Google is not returning billions of results. Just the first hundred along with a count of the total results.",
"Because Google crawls the web, and as it finds webpages it makes an index with keywords that appear on each page. Then when you search for a term, it looks at those keywords and the words in your search term and then at it's index listings that match that search term with a bunch of other factors (Such as who else links to this webpage, how many times has it appeared relevant to this search, etc), commonly known as the Google algorithm, it then presents those results to you. You can actually do something to help searching for files on your computer be almost as quick. When you search for a file, windows has to browse through all the files in your hard drive. As it does this it builds an index a bit like google does, only it refers to files on your hard drive. You can see this for yourself. Search for a file on your hard drive, and then after the computer has shown you all the results, search for the same item again. Windows will find it much quicker this time because it has built an index so if you type a particular search phrase, it knows where to look. But you can speed the process up even more. Imagine you went to Disneyland one year. And you took a picture of your girlfriend Jessica posing with Minnie Mouse. Now you get home, you copy the photos off your camera or phone and store them on your hard drive. However your phone/camera saves the photos with a title like DCIM00001, DCIM00002, DCIM00003, etc. Years go by and those photos get buried on your hard drive. Then one day you and your girlfriend decide to get married and you think it would be really awesome to have her picture with Minnie mouse that time you went to disneyland on a picture board to hang in your kitchen. So you go on your computer and...what do you search for? So you enter \"Disney photos\". But it doesn't find the photo. So you type \"Minnie mouse\". But it doesn't find the photo. \"Jessica\", \"Disney\", \"Vacation\" all fail to bring the photo up as well. Exasperated, you go looking for them manually and eventually you find the photo in C:\\old stuff\\my stuff\\old photos\\summer 2016\\DCIM00001.jpg. Your computer is never going to be able to build a file index by doing that. So the way you speed it up is by naming your files as if you where searching for them. Had you relabelled the name of that photo to \"summer 2016 disneyland trip jessica posing minnie mouse.jpg\", your computer would have indexed that and your search would have found it near instantly. tl:dr Google looks through the whole webpage to find the terms your looking for. Windows just looks through the names of the files. If you name your files as if you where writing a search to find it, Windows will index this and find it much, much quicker."
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cvhsky | How does Braille work? | Technology | explainlikeimfive | {
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"Braille is separated into blocks of 6 spots, called cells, which can either be flat or indented. Different combinations represent different letters, numbers, punctuation, ligatures, or other special things like capitalization. A diagram of a portion of the braille alphabet is [here]( URL_0 )"
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cvhwvd | why can’t we have car radios that work like DVRs, so we can pause or rewind broadcasts? I hate missing the first part of something, and I’m spoiled by DVR technology. Thanks in advance. | Technology | explainlikeimfive | {
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"My Subaru has this. When I get a phone call the radio (AM/FM/Satellite) pauses, and then resumes right where it was when I hang up. You can also rewind up to an hour.",
"You totally can! There is nothing really stopping this from being available other than the manufacturers of AM and FM radios not seeing it as needed. That said, XM does have such a rewind function."
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cvj3cc | How do cloud virtual machines (AWS, Azure) display your desktop? | I was recently experimenting with Azure Windows virtual machines, and noticed something strange: when you provision a virtual machine, you can configure your CPU, RAM, and SSD, but the graphics card seems to be missing. I always thought you need a graphics card to display what’s on your screen—could someone walk me through the specifics of how virtual machines stream your desktop to your computer? Thanks!! | Technology | explainlikeimfive | {
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"At the core all you need to display an image is to do some math and generate an image in memory. After that some additional hardware is needed to translate that stored info in memory into HDMI or VGA, or whatever protocol your monitor uses. With a virtual machine you don't even need to have that extra bit of hardware, instead using a virtual monitor. (Basically just some space in memory to hold an image) What a graphics card does, however is add a lot of special processing hardware (your GPU) and dedicated RAM for graphics only to make the math needed to run gaming graphics go a whole lot faster. Virtual graphics instead uses the CPU and system RAM to do the same thing. Processing power and RAM is just shared with the rest of whatever is running on your PC. For just showing a desktop this is usually enough. Edit: Changed integrated to virtual cause that's the right term."
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cvjzip | why do video games cost so much to make? | I always hear that Triple A video games cost millions to make why is that? Is it that all cost of workers? Does it cost money for a single person to make a game? Thanks in advance | Technology | explainlikeimfive | {
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"Let's just take the basics of producing a game (and I'm sure I missed A LOT). From the top of my head: \\- Licensing an engine \\- Licensing an IP (if not working with an original one) \\- Paying the writer \\- Paying the design team, layout team, animation team, level design team, texture team, coding team, scripting team, management, \\- Contracting a voice acting company for recording, paying actors, mixing, editing, SFX \\- Contracting a composer (or several), hiring an orchestra, paying for the recording studio, mixing, editing, etc. Licensing any existing tracks vital for the score. \\- Paying/contracting a software testing team \\- Paying the overheads, electricity, 401K, insurances, cars, coffee, etc. \\- Paying for marketing, ad presence, con presence, news presence \\- Printing and producing physicxal copies, merch, etc. Now you CAN do nearly all of that yourself, and drastically cut down on cost, but you will have to be a trained programmer/writer/musician/businessman/marketing expert. And there's not much of those running around since the Commodore days.",
"Get 100-200 highly smart and highly paid people on a team and pay them for a year to make a game. It adds up real quick.",
"Teams can be quite large, and a small number of teams I've worked on have had over 200 employees. Office space has to be paid. Salaries have to be paid. The lowest paid devs usually still make 50k annually. I suspect (but am not sure) the average salary is at least double that. Hardware has to be bought and paid for. This includes monitors, computers, accessories, and if it's for a console game, special consoles known as dev kits. I haven't worked on console in a long time, but I seem to recall back in the early/mid 2000s, a console dev kit could be over 20k. And you'd need a lot more than one. If you are publishing for a console, you also have to submit your game to the console manufacturer for testing to ensure it meets minimum specified requirements and a few other requirements. That's also expensive because you have to pay the console manufacturers to submit the game for their review. And you cannot publish on their platform without their sign off. If there is an online component, you also have to pay for the server farms. To circle back to the salary bit... 100 * 50,000 = 5,000,000. So that is for headcount alone, and lowballing, for some of the larger game teams."
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cvk6x3 | What are biggest differences between battle rifles and assault rifles? | * Also, under what circumstances is one type preferred over the other? | Technology | explainlikeimfive | {
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"Mostly it depends on cartridge size. Assault rifle generally means a select fire rifle that uses an intermediate cartridge. Battle rifles are similar, but use full size rifle cartridge instead of an intermediate size cartridge. Sometimes assault rifle can mean any type of rapid fire rifle depending on who you ask though."
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cvkb1d | how do 360° cameras work? | Technology | explainlikeimfive | {
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"text": [
"Most 360° cameras have two fish-eye lenses. Each lens captures a 180° view of the area and the camera stiches the two images together to create a 360° view. Expensive cameras have more lenses so they have lesser distortion."
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cvkr8g | how cellular transmission works and why it drains the battery so much. What is the phone actually doing? | Technology | explainlikeimfive | {
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"In order for a mobile phone to talk to a cell tower a two-way communication channel has to be set up. This involves your phone yelling out ‘listen to me’ in the hope that a tower replies. If no tower replies, your phone will shout out louder, and louder, and louder until either a tower replies or the phone is at maximum transmission power. All that shouting will drain batteries, particularly if there are no towers around. Once you do find a tower, it will also tell your phone if you’re shouting too loud or too soft. So if you’re traveling between cell towers or at the edge of a cell, the tower will tell your phone to shout as loud as it can, so it can maintain the channel. And just to chew up your battery even faster, phones which continually look for wifi shout loudly looking for wifi too. *AND* there are other things your phone does continuously to burn batteries - GPS location calculations is significant also."
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cvlnnx | How are songs remastered? | Technology | explainlikeimfive | {
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"They are “mastered” using EQ and compression, which are audio engineering tools/tech. EQ is essentially volume control for separate frequencies, so you could control the volume of the low end (bass, etc) separate from the high end (treble, hi hats, etc). Compression is basically what it sounds like, it’s dynamic control and envelope-controlled limiting. If you’d like to know more about those concepts a cursory google search will help. Depending on what is being remastered, they may or may not have access to the track stems. This means the separate channels (guitar, bass, vocal, etc) are separate files and they can EQ and compress them separately which gives them more control as opposed to only having a “mixdown” which is just the final song as one file like you’d think of it, in which case they can just EQ and compress that single file, but there is less control with that because if you pull back the mid to tame down a vocal you’re pulling the mid of the whole track back so you pull mid out of the other instruments too. If I need to explain more or reword something let me know."
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cvm9mb | Why do battery chargers (the type that charges AA and AAA battery's) require 2 battery's before actually charging them? | Technology | explainlikeimfive | {
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"Because they're low quality. A high quality smart charger caters to each battery individually to give it the perfect charge, and maximize its life. The funny thing is, the highest quality charger on the market only adds about $6 to the cost of these AA Eneloop NiMH batteries: * [AmazonSmile: Panasonic K-KJ17MCA4BA Advanced Individual Cell Battery Charger Pack with 4 AA eneloop 2100 Cycle Rechargeable Batteries: PANASONIC: Electronics]( URL_2 ) * [HKJ Review of Charger Panasonic BQ-CC17 - URL_1 ]( URL_0 ) > A nice -dv/dt termination with only a small temperature increase and no trickle charge, this looks very good. [...] The charger is very good at filling the batteries. You need that charger to get the full life out of Eneloops. If you take care of them, Eneloops will last at least a decade, maybe longer. The charger also works with other NiMH batteries. If you don't have good NiMH batteries yet, get the ones I linked to above, and make sure your battery specifications match the packaging in this photo *(there are fakes out there): * [New battery day! 24 AA Eneloop NiMH batteries in 16 and 8 cell packs. : r/AAMasterRace]( URL_3 )"
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cvn7jj | How do refrigerators work??? | Technology | explainlikeimfive | {
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"A refrigerator works by moving heat from the interior of the box to the outside. This requires a refrigerant that changes temperature when it changes density. If you have ever emptied a can of spray paint, or other substance under pressure quickly, you may have noticed the can gets cold. Refrigerators use this principle with a compressor that pumps the refrigerant to a high pressure, then pushes it through a heat exchanger on the outside of the box, usually mounted on the back of the unit. These coils will be hot to the touch, but get cooler the further the fluid flows. Then once the fluid has cooled 30 or 40 degrees, it goes through a nosle into a larger diameter pipe, causing it to lower in density into a gas and get cold. It then goes through a heat exchanger with fans on the inside of the box, cooling the air, and causing a chilling effect. The low density gas, then goes back to the compressor, and is compressed into a hot fluid, completing the cycle."
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cvofqx | why are car navigation and voice controls so clunky when we have the technology in phones to be very smooth? | Technology | explainlikeimfive | {
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"Siri and all those like it ship the audio off your phone to a server at Apple/Google/wherever to do the speech to text processing. They have huge farms of optimized servers for that. Your in-dash navigation system has to do it all itself with a relatively slow processor.",
"There's a few reasons. The main one is that auto manufactures have been extremely reluctant to allow another company to take \"possession\" of the vehicles infotainment system. Car companies are good at making cars. They are less good at making voice control systems. They could outsource this processing to someone like google but the car companies don't want to lose that level of control and access to the data. So they have been extremely resistant to doing this. Next issue is development timelines. Most cars take 5(ish) years to develop before they actually go on sale. At some point in this process the infotainment system becomes \"locked in\" for production. Then the actual model of car is sold, basically unchanged, for another 5(ish) years. Sometimes development is a lot longer, sometimes the sales period is a lot longer. But it's not unreasonable to think that the infotainment system in a \"new\" car might have been designed 5-10 years ago, that's a LONG time when it comes to something like a voice assistant. Go research what Google and Apple were doing in 2009 (hint, nether google assistant or Siri existed then). There's 2 more factors. The first is known as the data advantage. Google, Amazon and Apple have gotten as good as they have at voice control because they have been collecting voice control based data for a long time. The more voices that these services can hear the better they can become at learning what people are trying to say. Car companies sell a lot of cars but it's not nearly as many as smart phones are selling, I know many people who don't have their own car but I don't know anyone without a smartphone (or who shares a smartphone). Most 16 year olds have their own smartphone but most don't have their own car. So there's the fact that the car companies have WAY less data available to them to collect, combined with the fact that most cars are not sending this data back home. And this leads us to the next point. Most smary voice systems today don't actually do the \"smart\" thing on the device itself. A google home is just a recorder with an internet connection, not a speak renegotiation processor. It records you, sends that snip of a recording to google's BIG server farms where google processes it and returns a result, the speaker then plays the result. It all happens very fast and is dependent on an \"always on\" internet connection. Most cars don't have an internet connection like that. So a car is doing all of the speach processing using the computer in the car. A computer that is already somewhat old and outdated, built by a company that builds cars and not computers and it's more of a general use computer not one specifically designed for speech to text processing. So it's just disadvantage on top of disadvantage. All of these are why things like Android auto and Apple CarPlay exist. These services allow your smart device to control the head unit of the car. It basically becomes just a dumb display. But even with that innovation auto makers were still very resistant to allow it. They don't want to give up control of the central screen in the middle of the car. But because they really suck at this stuff they are slowly having to let go. It's now possible (but only just barely possible) to buy a car that has it's primary infotainment system built around Android, but it's not widely available and I think it's only 1 or two models that are mostly in the design stage."
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cvq0bs | Why does train WiFi not work in tunnels if the WiFi is located on the train? | Technology | explainlikeimfive | {
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"The wifi on trains works because there is a satellite connection, in a tunnel the train and satellite cant see eachother, so therefore the wifi goes away."
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cvq4iq | How does GPS know it's inaccuracy? | When you use google maps, it says how inaccurate it is. If they know the inaccuracy, couldn't they just use that to calculate the exact position? | Technology | explainlikeimfive | {
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"It's about how the GPS actually works. Your phone is \"listening\" to signals that a series of stalactites are putting out. Basically these satellites are all constantly sending signals that contain the current time. Your phone takes the signal, compares the time codes to the other signals and is therefore able to determine how far it is from the satellites. So my phone knows it's a certain distance from a satellite, and the position of the satellite is a known thing. Problem is my phone has no idea what direction the satellite is in. However if it can hear 2 satellites, or even better 3 or more, it can use those 3 distances to figure out with a lot more accrual where it is. It's drawing circles around where the satellites are and where those lines intersect is where you are. SOOOO accuracy is based on how many satellites it's currency hearing. It's also based on the strength of those signals. In addition the older satellites might be less accurate and so on. There's 2 other factors. Your phone does not only use GPS to get it's location. It can also use the cell phone network, it knows what tower it's connected to and the location of that tower. So sometimes your \"GPS\" location actually shows the location of the cell tower. So when you first open maps the location will be HUGE and way away from you. Then it will snap to something much more accurate. That's your phone swapping from using the cell tower location to using your actual GPS location. Lastly your phone can use it's wifi network to determine location. I'm somewhat understand on how this one works but it's some combination of the wifi network being able to tell the phone what address it's at combined with the major phone makers having access to some kind of wifi network map that the phone can use to see what networks are around and use that to determine what it's rough location is. So your phone has 3 methods, all 3 methods have differing impacts on location accuracy along with battery consumption so your phone will attempt to get the best accuracy with the least battery impact.",
"It does, that's one of a few reasons GPS has gotten better in the last decade. First: GPS uses satellite signals to figure out where your phone is. Think of each GPS as a spotlight creating a large circle on the earth (the spotlight is the signal). As you end up in the spotlight of two satellites the phone knows you're in the area they overlap. Add a third, and the location gets more precise. My running watch waits for at least 4 before it's considered \"accurate\" and will track up to 9 at a time. The area of overlap that you're in is the accuracy. When signals are stronger and clearer, the phone can \"see\" rings within the spotlight (it uses signal strength, time delay and other math), so instead of a spotlight, you now have a narrow band of area within each spot light that you could be. You have to add some \"vibration\" to the signal, since everything (earth, satellite, your phone and objects in the way) is moving and the signal is bouncing off of buildings and mountains - not to mention other signal noise. This adds to the the inaccuracy your phone might report. As computers in phones get stronger and the physics is understood better some of the uncertainty can be factored out to increase accuracy. A compass in your phone, and a knowing that you're in your car and moving along a road, can help the phone figure out that you were at point A, traveling along a road - and it will fill in that you're at point B next, not D or F (the other possible locations). Signal isolation is getting much better as well as the strength of the receivers . At the end of the day, there will still be some inaccuracy - but it is getting better. With all the money behind self-driving cars, drones and other location dependent technology, expect this to happen rather quickly."
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cvrm85 | How can a PC benchmarking software force even the strongest hardware to its limit? | By this i mean sometimes a benchmarking app is just a looping 3D model but what about those 3D model that can make our PC overheat? | Technology | explainlikeimfive | {
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"Because it tells the hardware to compute something as quickly as possible. Even the strongest quarterback can throw a football only so far and even the fastest runner can only run 400 meters in so fast."
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cvvzah | How can phones make emergency calls even when there's no signal? | Technology | explainlikeimfive | {
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"The phone may display that there is no signal to a cell tower in the network for which you have service, but there may be a signal for a different network. All cell towers are required to carry emergency calls so you may still be able to call emergency services regardless of what your phone would indicate.",
"There are many towers owned by many different telephone companies. For normal service, your cellphone only connects to towers owned or rented by your telephone company. But the government requires that for emergency calls, your phone be allowed to connect to *any* tower. So, even if you're outside the coverage area of your AT & T service, you can still make a call through the Verizon towers. This doesn't apply everywhere - if you're out in the middle of the desert or on a mountain you will most likely have absolutely no service regardless just because there are no towers available there."
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cvxfu6 | Difference between piano and keyboard? | Technology | explainlikeimfive | {
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"Differences include: Number of Keys — pianos have a standardized set of 88 while keyboards can differ Key Weight — piano keys have different weights by default while keyboards usually have weightless keys Sound Quality — there are some pretty great electric keyboards out there but the ones you’ll commonly see just use midi or low quality samples. By contrast it’s rare that you’ll ever run into a cheaply made piano and even older, less cared for pianos have a decent sound, all things considered. Dynamic range — Most common keyboards lack this. A piano’s volume will change due to the amount of force a player puts on it. Keyboards have a volume fader or knob but that’s typically it unless you want to approach high-end modals. Peripherals - A piano typically has 3 pedals: sustain (holds all notes after the key has been released), half sustain (only keeps the lower half sustained), and damper (makes the piano quieter through various means). A keyboard may have an external sustain pedal but you can also connect it to your computer or to other cool peripherals and devices. Size — even the smallest pianos take up a lot of room (especially since Wurlitzer went out of business) and are very loud when played in a house. Keyboards can be as small as a book and you can put your headphones in them to practice. Unless amped they aren’t loud at all and some don’t even have internal speakers (these are usually just called Midi Controllers) Cost — the cheapest, good quality pianos will run you a few grand *at the very least.* You can probably buy a keyboard for like $20 online. Even really high end ones cost about as much as a basic piano. Then, of course, pianos are acoustic while keyboards are electric. If you want a keyboard that plays like a real piano you’re looking for a Digital Piano. If you want a high end keyboard with a lot of cool functions go for a Nord. If you just want something to mess around with or if you want to experiment with electronic stuff go for a midi controller of some kind (whichever works for you because you can offset almost of the actual sound design to your DAW).",
"It's like the difference between a fruit (a general category of food) and an apple (a specific type of fruit). In this case, \"keyboard instrument\" is the general type of instrument, something played with a board or set of keys - it can include pipe organs, electronic keyboards/synthesizers, etc. A piano is a specific type of keyboard instrument that is a percussion instrument.",
"A piano has strings that make noise when you hit the keys. A keyboard is electronic. You typically plug it in, or it uses batteries. No strings inside."
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cw1w6m | What are arrays in programming? | I have recently started learning javascript and i don't understand arrays. The way how people explain is confusing. Can anyone explain to me in a very very simple way without using words like 'entities', etc.? | Technology | explainlikeimfive | {
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"You know what a variable is, yes? x = \"fred\". Simple. Now, imagine you have a set of 500 words, and you want to store each of them in a separate variable. Sure, you could do: x1 = \"once\" x2 = \"upon\" y = \"a\" z = \"time\" and so on, but it would be a problem. First, it would take ages to write the code. Secondly, if you wanted to step through each of those 500 variables, to process each one in turn, it would be really difficult. So an array is a variable which can be split into compartments. You might have an array called x, and then do: x\\[1\\] = \"once\" x\\[2\\] = \"upon\" x\\[3\\] = \"a\" x\\[4\\] = \"time\" and so on. Now, if you want to print out the contents of the array, you don't need to know which 500 variable names you chose, because it's all x. You just set up a loop like: for (count = 1 to 4) { echo x\\[count\\] } Here, x is a one-dimensional array. Like a row of cells on a spreadsheet. You can have 2-dimensional arrays too, like a grid: x\\[1,0\\] = \"once\" x\\[1,1\\] = \"upon\" x\\[1,2\\] = \"a\" x\\[1,3\\] = \"time\" x\\[2,0\\] = \"lived\" x\\[2,1\\] = \"happily\" x\\[2,2\\] = \"ever\" x\\[2,3\\] = \"after Then you'd use 2 loops, to step through each value of each dimension in turn."
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cw38t8 | What is LinkedIn supposed to be? What is it’s purpose? | Technology | explainlikeimfive | {
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"I use it to identify key staff in a company I have interest in. Google linkedin \"the company\" and the role title you are after and quite often you'll get a name to contact. Really handy for companies with gatekeeper receptionists that won't put you through to someone you need to talk to if you don't have their name whilst cold calling."
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cw56gh | how was electricity first discovered? And then utilised? | Technology | explainlikeimfive | {
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"That depends on what you mean by \"discovered\" or \"utilized\". We have records of ancient Egyptians discussing electric fish from almost 5,000 years ago. People have long known that when you rub certain substances together (amber and fur, for instance) that weird things start to happen (they can make things move mysteriously and you can get shocks). They also figured out that some of these properties go through certain things (like metal) and not others (like wood). Over time people learned more and more about electricity. Ben Franklin famously discovered that lightning had similarities to sparks (although there is a lot of evidence that Arabic scholars knew this in the 15th century). Faraday discovered that electricity and magnetism are related in the early 19th century. It seems likely that early humans carried fire around that had been started by lightning (before they learned how to start fires themselves). The obviously had no idea this had anything to do with electricity but it was certainly a use. There are Roman artifacts that may have been batteries that were used for light. By the late 19th century people were using electricity to run telegraphs. That may be one of the first widespread uses.",
"Ancient Greeks discovered static electricity when they rubbed amber and fur together. Most people knew it existed from then on, it just wasn't useful. Some have theorized that Roman's had primitive chemical batteries, but do not know what they would've been used for. It wasn't until much later in the early 1800's that Alessandro Volta built a battery that could sustain a constant flow of electricity. However, these were only chemical batteries, which was an impractical way to create current, as one would need a constant supply of the chemicals. By 1830, the dynamo was invented that allowed electricity to be generated. This allowed the invention of the telegraph, which was the first widespread usage of electricity. It took time, but eventually more electrical inventions were placed into wide use, such as the light bulb, wireless radio and telephone. Electricity didn't start entering homes until the 1880's, when the light bulb became reliable enough to be commercialized. From then on, the systems evolved until what we have today."
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cw6htn | What makes batteries chargeable and how are they charged in the first place | Technology | explainlikeimfive | {
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"There are two types of regular (AA for example) batteries. Non rechargeable batteries have two chemicals that send energy from one to another through a device. Once all the energy has moved from one end to the other or been used by the device, the battery is dead and must be disposed of. Rechargeable batteries have two different chemicals. When plugged in to a battery-operated device, they work the same way as a non-rechargeable battery. But when plugged into a device with something else on it providing the energy, like your wall power outlet, the energy can be pushed backward and refill energy in the first chemical. When you try to recharge a non-rechargeable battery, the energy isn't moved back, and instead turns into heat. This makes the chemicals really hot, until they explode out of the battery and make a really dangerous mess. That's why you shouldn't try to recharge non-rechargeable batteries.",
"Batteries are just a chemical reaction happening. Specificly an REDuction/OXidation reaction (Redox), which involves the exchange of charge, ie electrons. Thru clever design and an intermediary we can make the electrions travel down a path we choose, namy thru our electornic devices. So they are not \"charged\" in the first place. They are built with a charge in them. How they are recharged is you apply a reverse voltage to the battery. This drives the reaction in reverse causing the chemicals to go back to their initial state. This process is not perfect, which is why batteries get less and less powerful as they charge and discharge. \"Non\"-rechargeable batteries can't be properly charged as the chemical reaction doesn't reverse properly when the reverse charge is applied. So the chemicals do NOT go back to their starting state."
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cw73q5 | how do software drivers work? | Is there a brief explanation to understand how a bunch of 1's and 0's work together to install and make it function in your computer? | Technology | explainlikeimfive | {
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"A driver is just a string of 1s and 0s that tell your computer to be prepared for certain patterns of 1s and 0s coming from the hardware so it doesn’t get confused when it receives them",
"Let's say you have a really cheap monitor that only has four pixels in a row: 1-2-3-4. The cable leading into the monitor has 4 wires, each corresponding to a pixel. The video card on this computer expects a 4 bit value from 0000 to 1111. Depending on the value it receives, it will send an electrical signal down the appropriate wire to light up the appropriate pixel. For this monitor, The left-most bit controls the left-most pixel and each pixel to the right is controlled by the next bit in the sequence. But let's say there is another monitor of similar design, but they decided to have the left-most bit control the *right*\\-most pixel. Basically the opposite. How is your operating system supposed to know the difference? The answer is: it doesn't, and the monitor companies must provide drivers to get it to work. Rather than expect the operating system companies to know about all the different kinds of monitors that will be developed and all of the different kinds of inputs they will expect, we instead place the burden on the hardware companies to know about the different kinds of operating systems and all of the different kinds of outputs they produce. So company A with the first monitor develops a driver that converts the operating system output into a format that works with their monitor and company B does the same for their monitor. *How* does a driver do this? Well a driver is basically just a series of instructions. Instructions that can convert one string of bits into any other kind of string of bits. A specific driver will have a specific set of translations that takes all of the different kinds of sequences of bits the operating system might send it, then transforms them into the specific kinds of bit sequences that their hardware knows what to do with."
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cw7u6g | how do barcodes work when the same item is sent to different places with different register systems, different prices assigned, etc.? | Technology | explainlikeimfive | {
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"The bar code is just another way of writing a number, which is also printed directly below the barcode. What happens is that the manufacturer says \"this bar code number corresponds to this product,\" and all of the stores list it in their systems under that number. It doesn't communicate any information about price, however. So the store is free to assign \"UPC X = $Y\" in their own system totally independently of any other store's systems.",
"Lots of folks mentioning that bar codes are just number formatting, but there are international standards. A bar code does not have to be registered. Someone can manually enter any information that they like. But most bar codes are registered, so that the same number means the same information no matter who scans it. GS1 is the big organization which is most widely used. You pay an annual fee, depending on how many bar codes you need. It isn't some crazy high number either. If I'm remembering correctly, my place has 100 numbers and it costs us a few hundred a year.",
"Barcodes, in general, are just a specific way to encode an ID number. There's a specific way to read them. For example, this energy drink I've got in front of me has the barcode value of 610764863375. If I owned a store, I would have a system that I would need to enter all of the items I carry into. I'd enter this energy drink, with its description and barcode. When I scan the code, the system does a lookup for that number. It finds the energy drink record and outputs that price. The barcodes don't tie back to some other system in any way - it's just a specific way to identify that item."
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cwgsuv | When listening to music on Youtube, why does audio quality vary significantly depending on where I adjust the volume? (In-website vs on computer) | To elaborate: Listening on my laptop, I've just discovered that audio quality is totally different even at the same levels of volume, depending on where I adjust the volume. * If youtube's built-in volume plugin is set fairly low (say, 25%) but my computers volume is set to 75 or 80%, then the audio quality is noticeably worse. * If youtube's built-in volume plugin is maxed out, but my computers volume is set to say 25%, then audio quality is noticeably better. ELI5? Is this a youtube specific thing or should I notice this on every website/app? | Technology | explainlikeimfive | {
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"This is what's called \"gain staging\". Let's pretend that you have the ability to control the volume on someone's voice via your laptop volume. If that person is talking at a normal volume, you can comfortably adjust the volume on your laptop to 50% and hear them clearly. However if that person is whispering, you need to set the volume on your laptop much higher to hear the same \"volume\" - so you need to turn your laptop volume much higher than 50% to try to get the same result. Whispering is not quite as clear or as loud as talking normally, so you're amplifying a lower quality signal - which gives you a poorer quality result. In your example YouTube is passing a low quality signal (because of its volume) to your OS which is then processing the signal to send to your speakers. Ideally you want to pass the maximum signal possible along the chain without creating distortion."
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cwhsww | how come in movies when the cameraman is filming the actor looking in the mirror, you can't see the camera even if the camera should logically be reflected in the mirror? | This question has been plaguing me for more years than it should have. | Technology | explainlikeimfive | {
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"It's a little known fact, but there are a group of vampires in hollywood who are recruited a bit like stunt doubles but for cameramen when they need to film scenes about mirrors. There are also several alternate techniques that people who don't believe in vampires usually employ. First and by far the most common, the director takes advantage of the angle of reflection. Light reflects off a mirror in the same way a tennis ball bounces off a wall - that is, it only comes straight back at you if it hits perpendicular to the wall. For something to be seen in a mirror, light first needs to bounce off the object (in this case the cameraman), then bounce off the mirror straight back into the camera. When the camera is off to the side though, the light bounces in the opposite angle, so the camera doesn't see the camera in the mirror. This is why most mirror scenes are filmed at an angle, rather than directly behind the actor in question. Secondly, you can not have a reflection at all, and construct the entire reflected scene in CGI. Thirdly, a technique done in Terminator when they wanted to do a panning shot around a mirror. They used a wall of glass instead of a mirror, put the actors in a duplicate of the set on the other side of the mirror then used dummies on the \"real\" side.",
"It is just a matter of angles. You can try it yourself. Go to your bathroom mirror, place something in front of it, move to the side. At some point you will stop seeing your reflection and still see the object. (Or hit a wall, if your mirror is large and the wall is close, in that case, repeat the experiment with a portable mirror somewhere roomier) You can also get the same effect from going higher instead of sideways, or doing a combination of both. And in studios they only build the walls you see on camera, they can get as wide and as far or high as needed. Sometimes special effects are used, maybe even gimmicks like extra mirrors or camouflage, but that's expensive and last resort."
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cwi2wc | How do Chinese keyboards work? Having literally thousands of characters in their language, how do Chinese build characters with a limited amount of keys? | Technology | explainlikeimfive | {
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"You don't type the characters, you type what the character sounds like, then a list of suggested characters pops up and you choose which character you want. See [this]( URL_0 ) for example.",
"The process is called transliteration or pinyin, in the case of Chinese. You use a QWERTY keyboard to phonetically spell the word in the Roman alphabet. Most, if not all, devices will show Chinese “autocomplete” options to choose from as you begin to type.",
"Oversimplification but: Imagine the word 'window' looks like this 田. You type the word window, hit spacebar and then the program says \"did you mean 田?\" Now let's take the word 'bear'. But dang, bear could mean an animal or it could mean 'to carry/shoulder something'. So this time when you type 'bear' and you hit spacebar the program says \"did you mean 🐻 or 🏋️\""
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cwkywt | what are voxels used for in brain imaging? | Chose Technology as flair but I'm guessing neuroscience also involved. | Technology | explainlikeimfive | {
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"Voxels are just 3D pixels. That means, one voxel is one point in a 3D image, just like a pixel is one point in a 2D image like a photo. I.e. a x,y,z (height, width, depth) coordinate mapped to another value such as color, or e.g tissue density or blood flow in brain imaging."
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cwl5ip | Why are missing textures in video games portrayed as purple-black squares? | Technology | explainlikeimfive | {
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"So they stand out. Developers usually show missing textures that way so when the game is being tested it's obvious if a texture is missing.",
"Devs get to choose what the 'missing texture' texture looks like. They usually create a default texture file that gets applied to anything they forgot to assign a texture to. Most devs choose that square pattern both because it stands out and because its kind of 'tradition'. Testers, no matter which game they're testing on, know that black and purple checkers means \"this is a texture not found bug\" - and therefore not any of the other bugs that can lead to texture issues."
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cwl9qc | Before there were search engines like Google, how did we request files from the world wide web? | Technology | explainlikeimfive | {
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"text": [
"The same technology for requesting a file is still used today. Google and search engines before it just made *finding* the site you want possible. In order to visit any website you just typed out the full URL. How did you know the URL? It would be written somewhere such as an ad. Of course once you have the URL you can also keep it bookmarked. Alternatively, the web had web directories - websites that simply had lists of other websites, divided into categories. You usually set up the directory as your starting URL and went on from there. For example, [this]( URL_0 ) is what Yahoo looked like back in 1996.",
"When you request a file, your computer asks another computer \"Hey, can you send me this file?\" and that other computer sends the file to you. Search engines do not store files, they simply say \"Hey, if you're looking for these kinds of files, this computer might have some you're interested in\", like a phone book giving you numbers for plumbers or carpenters.",
"Well before Google there was Webcrawler, but mostly, you just had to already know the URL address."
],
"score": [
7,
5,
3
],
"text_urls": [
[
"http://web.archive.org/web/19961017235908/http://www2.yahoo.com/"
],
[],
[]
]
} | [
"url"
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| [
"url"
]
|
|
cwm4oh | How Two-Factor Authentication is secure when you can submit any phone number to authenticate? | I just logged into my google drive account; I already have my phone linked to my google account, and they wanted a two factor authentication, no problem, but they let me submit a phone number to authenticate with. It didn't auto choose my own. How is this secure at all? | Technology | explainlikeimfive | {
"a_id": [
"eycqab6",
"eycxrew",
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],
"text": [
"Two-Factor Authentication is secure if the person setting up the 2FA is the owner of the account. Just like a password is more secure if the person who sets the password is the owner, and it's insanely insecure if it's set by someone who shouldn't have access in the first place.",
"As soon as you have set up 2FA it becomes way more secure. To change your 2FA phone number again you need to confirm it with your old number.",
"Do you not have your account setup on your phone? When I log into google stuff on a new account my connected phone automatically get's a prompt asking to confirm login. I can either click yes or no (well whatever the buttons are titled) to authorize or block the login attempt. If that doesn't happen in X amount of time it simply doesn't log in. Only time I have to use text 2FA or something is if I reset my phone and they want to confirm the phone number is still mine before allowing the phone itself to access the account."
],
"score": [
14,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
cwmjsl | How do near-black colors work on OLED screens? | I've read that OLED displays work by turning off electricity for an individual pixel which is displaying pure black, eliminating the backlight and displaying the deepest black possible. My question is, as soon as you have something that's almost black, but not *pure* black (like `rgb(1,1,1)`), does the depth of the black go back to being just as good/bad as a regular LED screen? If not, then how? | Technology | explainlikeimfive | {
"a_id": [
"eycywk2",
"eycvfqj",
"eycxec2"
],
"text": [
"OLED pixels only produce as much light as they need. black produces no light so it uses no electricity. dark grey produces a little bit of light, so it uses a little bit of electricity OLED power use can be approximated with a simple calculation. take each pixel's RGB values, translate them to luminance, and add them together (in reality each subpixel has a different efficiency rating you have to factor in. green at 100% brightness doesn't use the same amount of electricity as red at 100% brightness). the result: OLED uses less electricity for a lot of content, even if it's colorful. but it uses more for things like websites that are mostly white background",
"OLEDs don't have a backlight. That's what makes them better than LED. You're describing local dimming with full array backlit LED's",
"each OLED element emits light separately, which is different from the prevalent non-emmitting LCD displays which merely filter a backlight. so in the case of LCD (now with gridded LED backlights), turning off a portion of the backlight will have this effect you are mentioning, a noticable gap in luminosity from the *almost* black with the LCD value attempting to block all of the backlight, to `rgb(0,0,0)` with the backlight off. but since the OLED elements are the emitters, themselves, they are tuned in manufacturing such that a value of `1` is just barely emitting and is as close to indistinguishable from `0` as their gradient allows. so to sum it up, local dimming/disabling of a coarse grid of LED backlights (in LED backlit LCD displays) will not have the same effect as individually dimming each emitter independently (in OLED displays)."
],
"score": [
9,
8,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
cwokav | Safely eject USB key feature on desktops. | How does it work? | Technology | explainlikeimfive | {
"a_id": [
"eyddr5w",
"eyde1xi"
],
"text": [
"In the days of yore, USB drives were slow. So if you needed to work on a file on a usb, the file manager would do a little trick. When you hit save, it would save that file to RAM really quickly so you could get working again quickly instead of waiting 30s for a file to save. Then while you were working, it'd slowly transfer that data to the USB drive in the background. If you pulled out the USB while that background transfer was happening, you'd end up with a corrupt file. Safely Ejecting basically makes sure that all the data transfers are done before it says it's safe. It's not as much of an issue now that USB 3.0 is the norm; larger files never went through this background process, and smaller files take almost no time to finish.",
"Plugging in a USB key to a computer is like a ship docking into a port. When docked, the ship can unload (read) or load (write) supplies, people, fuel, etc. You wouldn't want the ship to start moving away (ejecting) without making sure you stopped loading and unloading! In the worst case, the goods may just drop directly into the sea (data corruption)! Selecting a drive to eject makes the system check if the ship can stop loading and unloading. Once this is cleared, the ship can safely undock and be on its way."
],
"score": [
40,
16
],
"text_urls": [
[],
[]
]
} | [
"url"
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| [
"url"
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|
cwqmrx | Why is CCTV footage so bad in quality when other types of cameras can film very well? | Technology | explainlikeimfive | {
"a_id": [
"eydvygm",
"eydvuhe"
],
"text": [
"The better quality you have, the more expensive it is to purchase, the more storage space it requires, and it might be less reliable. You might not want to spend $20,000 on a setup if $5000 is enough, even if it means you get \"bad but usable\" quality instead of amazing quality",
"I imagine it might have something do with the high quality footage filming over this amount of time will take up a lot of storage space."
],
"score": [
13,
8
],
"text_urls": [
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
|
cwso7j | How does data get corrupted over time? | Technology | explainlikeimfive | {
"a_id": [
"eyeliwn"
],
"text": [
"Data doesn't get corrupted. However, data is stored in some media and that media can deteriorate - resulting in corruption. The causes of corruption depend on storage technology, and some technologies have very long lives (think gall ink on parchment). Flash drives store information in a microscopic capacitor, where a cosmic ray could easily change a 1 to a 0 or vice versa. Magnetic drives have tiny iron particles magnetized, and many electric currents can change them through stray magnetic fields. Optical drives, like CDs, have bits carved in a thin layer of aluminum. This it super durable, but scratches in the plactis surface can make the data unreachable."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
]
| [
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|
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