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evggiu | Why are TVs and pictures rectangular when camera lenses are circular? | Technology | explainlikeimfive | {
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"The lenses are circular but the sensor inside the camera is rectangular or almost squarish depending on the format.",
"Not only are modern cameras built with square censors, but analog cameras recorded photographs and video on squared pieces of film. This is because it's easier and less wasteful to have the film be a series of squares, as opposed to a series of circles. The visual data lost to the translation of the circular lens to the square view is the edges, which tend to be the most distorted parts of the image anyway, so it works out."
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evl3ax | Does anyone here know what drop shipping is, or how it works? | Recently came across this term, and that it was some kind of online scam (?) or something, similar to forex trading (?). Couldn't get through enough of the Wiki to understand wtf was going on. Was hoping someone could explain | Technology | explainlikeimfive | {
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"Drop shipping is when a vendor sells and charges you for goods but does not send those goods to you from their own warehouse. They, in turn, buy them from (usually) a much larger seller and send the goods directly to you instead of first shipping the goods to themselves and then shipping them to you from their own location. EDIT: grammar.",
"It is when you are a business selling stuff but you don't actually have your own warehouse and instead have products ships directly from your supplier to the customer. This is a common way of handling logistics and does not indicate a scam by itself. In some areas it is a quite normal and logical thing to do. However it can also be used by small, new companies that mostly exist on paper and that don't have many funds and that sell stuff without actually adding much to the process other than extra costs and an unnecessary middleman.",
"When you order something from a company and they have the item shipped from a warehouse or supplier directly to you.",
"Drop shipping is when a company sells merchandise or profits but don’t actually have them in their possession. When a customer buys from them, the company then goes to the supplier or producer, orders the item, & then it’s shipped to the customer directly from the supplier. Let’s say I sold vacuums on eBay. I get 10 orders on-line & turn around & order 10 vacuums from Dyson. I get the wholesale price of buying 10 vacuums & they are shipped directly to my 10 customers from Dyson for a higher price."
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evncir | What exactly is an SSLVPN? | Technology | explainlikeimfive | {
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"SSLVPN's secure connections so that people outside can't see what is going on. It's a Secure Socket Layer Virtual Private Network. The SSL part is just a type of encryption. For this example, I'm focusing on VPN's as service rather than point to point VPN's used in business. Think of the internet like a delivery tube that connects all buildings in a city and it carries packages. Food, mail orders, letters, anything you want gets delivered to you. However, if someone wanted to track a person to see what they are doing, they would only need to put a camera in a station where packages are sorted and they would be able to track the packages and see what is in them in cases. They could see what you buy, what you send and who your friends are. They can read your letters if they aren't in a sealed envelope and even if the envelope is sealed, they know who you sent letters to. A VPN fixes that. Think putting all your letters and items into plain, sealed, boxes. You can still see that the person is sending and receiving things and where it is going, but you don't know what it is anymore. Even better, in the case of VPN services, your blank boxes are sent to a company that promises that there are no cameras. They unpack your boxes and send the items to their destination and they receive your packages, box them and send them to you. The spies can still see the unboxed packages going into the company, but as it is all mixed up with other peoples packages, they don't know what gets forwarded to you and what is sent to other people. This keeps your packages private. TL;DR A VPN hides your data so other people can't read it. This then goes to a provider where it gets jumbled with other peoples data so third parties find it harder to spy on your data."
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evot0z | how does software harvest your clicks and then sell them to third parties? | Technology | explainlikeimfive | {
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"If you’re referring to that antivirus post from earlier, the software reads what you’re clicking links too and what you’re doing. That information is valuable to advertisers so they see what a person like you does. It’s a pretty simple application, kinda like a key logger. Edit: I only know what I know because I was at one point (and did not) considering developing an “ethical non-intrusive ad service” that would be transparent about information the service knew about who it served ads to and a way to delete that information. I stopped very early on because it didn’t seam feasible for a team of one or two devs. You always have to scope out your competition and see how they operate. Now I’m making a VR game.",
"Compare it to normal advertising on TV; the commercials tend to try and target the audience of the show. Kids cartoon? Commercials for nerf guns and dolls. NFL game? Beer, cars, and pharmecuticals. Software that \"harvests your clicks\" (Avast, based on the recent article) is basically creating a similar profile on a much more personal scale. \"This person spends 10 minutes browsing the front page of reddit before spending 3 hours on r/aww and r/pets. Show them a bunch of ads for dog food and kitty litter.\" And those ads will follow you. When you log into youtube or whatever other website, you'll get more ads for pet supplies and adoption drives. The money comes from those selling the pet supplies, lets say PetCo. PetCo will pay the Avast for your data, to make sure that they're getting the best opportunity for the ads to work. And that same concept will go for literally everything. I used reddit and pets because it's a pretty easy example, but if you spend a lot of time on sports websites, Avast will know which teams you support, and sell that information to the company that sells sports merchandise. Or if you're into cars, or video games, or whatever else. Avast tracks all of that, and sells the info to stores, so that stores can better sell you junk."
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evp6iq | How does the SAR sensor work in smartphones? | Technology | explainlikeimfive | {
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"Let's make it more ELI5 than the current best answer: Electricity is weird. There's actually a tiny electrical field *around* your body, and most living things for that matter. We can make super-sensitive sensors that read electrical fields. We can also know what the sensor will \"see\" if no living things are near a device. So we tune those sensors to look for changes in the electrical field around them, and how to recognize what it looks like when an object gets close. It's sort of like how even if your eyes are closed, you can still sort of tell if you're facing towards or away from a lamp. Your eyes are fancy light sensors, and your eyelids let a little light through, so by comparing the amount of \"dark\" you \"see\" through your eyelids, you can still figure out a lot about what you're looking at. This sensor \"sees\" tiny electrical fields. **Update** The biggest contention with my answer seems to be, \"But doesn't the sensor see the phone's electrical field?\" Let's revisit my answer and handle this again. > We can make super-sensitive sensors that read electrical fields. We can also know what the sensor will \"see\" if no living things are near a device. So we tune those sensors to look for changes in the electrical field around them, and how to recognize what it looks like when an object gets close. Yes, the sensor does \"see\" the phone's electrical field. You also \"see\" your nose all day long. But unless you really focus on it, you probably don't *notice* your nose because your brain is used to it being there and removes it from your perception. In the same way, the sensor \"sees\" the phone's electrical field but is trained to ignore that and look for *different* fields. *More technically*, the sensor is really looking for *changes* in the field. So for the first few seconds after the phone is on, the sensor might think there's an object nearby. The people who made the phone are already aware of that, so for those few seconds the sensor is ignored. After a few moments, the sensor settles down and says, \"Hey, the field's not changing anymore.\" THAT is when the phone starts listening. If the field changes, something must have brought a new field within the sensor's range. That *probably* means something with a field is near the phone that wasn't near it before, so the phone assumes an object is near. Later, when that thing moves away, the sensor notes the field has changed back to how it was earlier. Then the phone assumes the object is gone. Yes, that means things other than your face might get picked up. The engineers who made the phone don't care, all that matters is it detects a face within an inch or two accurately. Any other crazy thing that triggers it is probably someone having fun after reading an ELI5 post, and there's no harm if that is a \"false positive\".",
"A SAR sensor measures the surrounding capacitance. When something gets close, that capacitance value increases, and this increase from the baseline indicates what it is close to. Living beings give a larger increase than inanimate object. It’s very similar to a capacitance touch screen which will work with a finger but not if you’re wearing gloves.",
"A lot of people explaining the sensor itself, but there isn’t much explanation on its purpose, so here goes: Different regulatory bodies (FCC, EU, etc.) place restrictions on how powerfully your phone can transmit WiFi and Cellular signal. The catch is, these restrictions are not based on the absolute transmission power, but rather on how powerful the waves are *when they come in contact with human tissue*. Because waves become less strong as they travel, the further away you are from your phone, the more powerfully your phone can send it’s signal while still following regulations. This is the purpose of the SAR sensor, it can tell how far human tissue is from the phone and let the device adjust its transmission power accordingly. It’s a small performance optimization that lets your phone eke out a little bit more performance when your phone is say on a table or in your jacket pocket, rather than in your hand.",
"The top response is pretty close. The sensor just detects capacitance. People and pets have body's that have capacitance due to things like blood and electrolytes. If you try a sausage, it will work just like a finger. The physical contents are similar. Living vs nonliving detection is nonsense or just marketing",
"Imagine you have a pool full of water and a rock and sponge that are the same size. If you put the rock in the pool the water level will rise as the rock can't absorb water. The sponge on the other hand will absorb some of the water so the level will not rise by nearly as much. So long as you can accurately measure the size of the object and the level of the pool you can calculate how absorbent different things are. A SAR sensor works in a similar manner except it uses an electromagnetic field instead of water. If you have an electromagnetic field, and you can accurately measure it, you can tell how much charge is being absorbed by whatever is in the field. Living things tend to absorb more charge than non living things.",
"What phone do you have, and how did you access the sensor data. I really want to try it for myself now.",
"Which phone are you using? \"In the U.S., the FCC allows RF exposure from cellphones up to a SAR level of 1.6 W/kg (over 1g of tissue) with a maximum separation distance of 25mm\" URL_0 Not sure about any sensor detecting biological matter, but I know of the proximity sensor on most modern smartphones. Maybe it works in conjunction with proximity and a function of RF exposure measured from SAR?",
"Also, can someone explain why this sensor is useful?",
"Can someone tell me how I could test this sensor myself? It sounds interesting.",
"Anyone know how far away it can detect a person? Inches of feet?"
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evpxf9 | TCP and UDP in networking | These are two terms that when I hear them and then try and Google for answers, I'm just left even more confused than I was in the first place. | Technology | explainlikeimfive | {
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"TCP: - A: \"Hey can we talk?\" - B: \"Sure we can talk\" - A: \"Great, going to start sending you stuff now\" - A: \"Hey I'm sending you something, did you get that?\" - B: \"Yes I got it, here's my response, did you get that?\" *message lost in transmission* - B: \"Yes I got it, here's my response, did you get that?\" - A: \"Sure did thanks, I think we're done, confirm?\" - B: \"Confirmed, we're done\" UDP: - A: \"Hey here's some data\" - A: \"Hey I've got more for you\" - B: \"Hey I've got something for you too\" *message lost in transmission* - A: \"Oh here you go, some more data\""
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evreox | How come you can uninstall a mobile app while its working in the background but you cant do the same on PC? | Technology | explainlikeimfive | {
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"You sure can, just blow the sucker out of the water with task manager if it refuses to quit when asked. Android does the same automatically. The task won't exit? [Let's see if it can parry a SIGKILL.]( URL_0 )"
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evsbef | Does leaving your phone on the charger after it's fully charged damage the battery and eventually cause a shorter battery life? | Technology | explainlikeimfive | {
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"No, the purpose of the battery controller chips is to prevent these problems.",
"The new iPhone operating system alters your charging for this reason. If it notices that you are taking it off the charger when you wake up every morning at 6 am, it leaves the battery at 80% until, say 4am and then lets it go to 100%. URL_0",
"Different types of batteries behave a little differently, but you asked about phone batteries, so lets focus on those first! You can picture your battery as if it were a container for energy, almost like a very special kind of bucket. When you plug it in, that's like filling the bucket with some substance like water or sand. Just like you wouldn't want to over-fill a bucket with water (unless you wanted to see what kind of mess it would make haha), its not good to overfill your battery. Luckily, our bucket is a lot smarter than a plastic pail. When your battery gets close to full, your phone tells the charger to slow down the \"flow\" of energy so that you don't overfill your bucket. What a cool use of science! If you do leave a cell phone plugged in all the time, you tire out the phone's ability to prevent overcharging and it can reduce the life of the battery, but leaving it plugged in overnight most nights generally wont cause much damage at all. & #x200B; p.s. not ELI5 but some batteries don't prevent overfilling, so this answer doesn't apply to every possible battery. In particular, some nickel based batteries must be fully discharged before you charge them, and some batteries can experience extreme heat (and potentially ignite) if you charge them too much for too long."
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evtb6r | How did explorers and map makers have an accurate layout of the shape of the continents and countries prior to aerial vehicles? | Technology | explainlikeimfive | {
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"They measured them with an optical sight and long measuring tapes. This is how surveying worked until quite recently. The sight might be as simple as a [Plane Table]( URL_0 ) or a complex [Theodolite]( URL_1 )."
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evvcao | Why Is it so Hard in 2020 to Print Special Characters (é, œ, à, Û, etc.)? | Technology | explainlikeimfive | {
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"Technology has solved this problem a long time ago. Those keys are easily available using ASCII, and on mobile by holding the character you need. However, many of the people making labels and things aren't actually that interested in their jobs AND have no supervision, so they let the software go nuts and confuse itself, or take a \"shortcut\" compared to typing the right thing.",
"Newer devices all now understand Unicode, the universal character set that can encode virtually all of the world's languages. However, printers, especially commercial/industrial models, are often in service for years or decades. Older models may not have support for Unicode-encoded text at all, meaning they treat it as some other character set, leading to \"mojibake\" (random-seeming garbage text). Even if they do support Unicode, the built-in fonts will not have a \"glyph\" (shape) for every single Unicode character, as there are more than 100,000 assigned characters, most of which are rarely used, and more are assigned in every new Unicode version. If a printer receives a character it doesn't have a glyph for, it may substitute a replacement character. Source: I used to do I.T. in a warehouse where we had somewhere around 100 industrial label printers of varying age and capability."
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evxd1h | When you delete files permanently off your hard drive, where do they go and how does it work? | Technology | explainlikeimfive | {
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"They don't really go anywhere with a normal delete. Your computer knows where things are in memory by putting little markers at the start and end of sections that contain data. When you delete something it just removes the markers, which leaves that space open to get written over by new data. To permanently remove something you actually need to write new data on top of it. There are programs that will do that by just covering over old data with nonsense.",
"Hard drives are divided up into sectors. If you delete a file on a hard disk, all you are removing is the pointer to the first sector of the file. To really “delete” a file, you need some sort of file security software that writes multiple times over the sectors where the file resided.",
"You can compare data storage too if you store a number with normal 6 sided dice. Take 6 dice and put them so they show 654321. If you erase data from a hard drive it would be like if you turn all dice with 1 up. Where did the number you hade go? The answer if philosophical and it the same as where do deleted file go. Data storage use binary so you store data with only two option 1 and 0. Erase in the data would be setting them to zero This is if you erase the data from the storage device. In practice that is not what is done except by special programs because it is a slow process. Think of a storage device as a large shelf with numbered drawers with dices you can flip. You use one drawer as an index and store that file X is store in drawer 569. When you delete a file you just change the index remove file X from it and store that drawer 569 is no longer in use. The content of drawer 569 is not changed. When you later store more data you might reuse drawer 569 and flip the dices to store new data. Between the point, you removed it from the index and when you reused it the data was still on the drive and can be recovered."
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evy7b5 | How can computers render millions of polygons PLUS tesselation but start slowing down when you try to get them to put high res 2d textures over an object? | Technology | explainlikeimfive | {
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"Its mostly about RAM use and data bandwidth. 2d Textures take up a surprisingly large amount of space. A model may have millions of triangles, but a 2048x2048 texture has millions of pixels, and the amount of data taken up by a 2D color pixels is about the same as a 3D point. When you exceed a certain amount of memory use you suddenly need to shuttle textures from one memory area to another depending on which ones will need to appear onscreen which takes time to transfer."
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ew0loo | When your on the phone and it's on loudspeaker whats stopping it from echoing back? | Technology | explainlikeimfive | {
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"Modern smartphones, since at least the Nexus One, have a secondary microphone. This microphone detects 'ambient' noise in an attempt to limit what the primary microphone actually sends to the distant end. When you put the phone on speaker, this microphone picks up the output from the speaker, so it's flagged as 'ambient' by the audio processor.",
"There’s more than one solution to an echo cancellation. There’s mute swapping; ie, when you talk - mic works but speaker mutes; when other party talks - speaker works and mic is muted. (Majority of landline telephones which have speaker phones work this way.) Then, there’s timing: every GSM network on the planet has “intentional latency”, ie the sound has “ping 250ms”, so (and this is very codec-specific) “every incoming sound that matches outgoing sound and is 250ms late - is cancelled”. Also: majority of telecommunications audio codecs are “synthesizers”, ie they don’t really compress sound and send and then decompress and play; they are more into “play short male voice letter A”; like, they are less in common with MP3 and more in common with MIDI files. There are other techniques- but most of them are patented and industry is very secretive about it - but these are some well known. Also: if you remember those dial-up modems, and those “connecting” buzzing sound: well, like half of it is actually measuring an echo (like latency and volume of it) - so that echo can be avoided."
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ew0vph | How do devices transfer information wirelessly and how can the transfer speed be altered? | Technology | explainlikeimfive | {
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"Radio: Your phone, laptop, etc. have radio antennas on their Wi-Fi cards. It's the same mechanism that TV, conventional radio and Bluetooth use. Wi-Fi has a problem, though: If you have 100 devices in the same area, they constantly interfere with each other. Imagine 100 people on a basketball court, trying to scream messages to each other - they will constantly talk over each other. So the more devices in an area, the slower thr connection, as they have to wait for each other all the time. Something similar happens with cell phone connections, but these are slower anyway. So how do you improve it? First of all, some Wi-Fi standards are simply faster than others due to better encoding (think the \"language\" the devices speak needs less words per message), so if your router is 10 years old, changing it would help. Wifi also has two bands: 5GHz and 2.4GHz, with 5GHz being less common (so less inteeference from neighbors) and in general much cleaner signal-wise. See if your router and devices support it, newer ones most likely do."
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ew36ju | How can digitally filmed movies be remastered? | I read on previous ELI5 that celluloids can be always rescanned with higher resolution devices and that's why you can get HD, Full HD, 4K remasters of classic Sci-fi movies for example. But what happens when the film is completely made by digital cinematography? I got this because reading Vidocq was filmed like that. As far as I know, if you have a 100kB picture there's no way to get it to a higher resolution for the pixel quality cannot vary from the original. Maybe a little improving by interpolation but that's it. Thank you so much for your time. | Technology | explainlikeimfive | {
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"You’re partly right but the filesize doesn’t have much in common with the files resolution. Sure, it increases when you add more pixels but that actually depends on the used compression. It’s right that you can’t just scale an image up and expect it to be as sharp as before (you may encountered that while creating a power point presentation). Movie Studios who re-release a movie in 4K that was originally shot digitally probably reworked the CGI which makes effects look a lot better and also added features like HDR or Dolby Atmos. The image quality itself doesn’t really improve but with the right setup you’ll get a much better experience watching the movie. There are some [lists]( URL_0 ) available where you can see which movies are up scaled and which are not.",
"As you identify you are largely stuck with what you'v got when you shoot on digital, you cant magic more information out of the footage than is there. To make something digital a higher resolution you are inherently guessing at what the new pixels will be. Maybe what was released, at least to home video, was a downgraded format compared to the original footage because of the limits of VHS and CD and so you can get a more traditional remaster out of it.",
"Can someone explain how old movies are upscaled? Or link me to it?",
"Others are basically saying this as well, but just to emphasize this point, many professionals have been shooting digitally in at least 4K resolution for at least the last ten years. Recently, cameras have even been released that can do much, much larger resolutions (like Digital IMAX and RED EPICs). Obviously 4K as an exhibition format is much more recent, so films shot last decade at 4K, which may have originally been released on DVD/Blu-Ray (or even theatrically, when the standard digital theater was 2K), were downconverted to fit those resolutions, and can be maxed out to a 4K release for later. Obviously, as others have said, depending on how VFX work was done, a remaster might require brand new VFX. You see this problem with a lot of 90's TV, where the show itself was shot on 35mm film, but all the FX were done on a computer at SD resolution, so even if you rescan the negative, you'd have to redo all the VFX for a proper remaster."
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ew4sr6 | how do car heaters get their heat? | Technology | explainlikeimfive | {
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"The water that’s pumped around the engine to keep it cool is routed to the inside of the car. That water is of course hot from taking the heat away from the engine. Under the dash board in the car is a small radiator that the hot water runs through. Add a fan behind it and you have a heated cabin.",
"Also, some cars/trucks have electric heaters and fans that run solely from the car's electrical system (electric cars, some diesels, some rear cabin heaters), but those are much less common in the world to using the engine coolant & radiated heat method.",
"Side note: If your car is overheating, turning the heat on full blast (and opening windows if necessary) can help cool your engine.",
"Your car heating is sucking cold air in, passing it through the grids of the heater core. The heater core is part of the liquid cooling system of your engine, and essentially works like a radiator in a room heating. It will only be hot when the engine is heated up a bit though. Only then it will be able to heat up the cold air and effectively providing hot air to your passenger compartment. There are systems that allow heating operation right from the moment you get into the car. They are turned on by a timer or a remote control some time before. What they do is they are basically small fuel burners that heat up the cooling liquid of the cooling system. That way the heating works immediately, and also the engine is already warmed up.",
"Heat comes either from the engine or resistive heaters. When heat comes from the engine there's a heat exchanger in the dash (the heater core) that uses hot engine coolant to warm the air. Resistive heaters (electric powered) are seen in hybrids and all electric cars where there is no engine or the engine may not get hot quickly at all. Resistive heaters are also available in large diesel vehicles where you may be operating it somewhere it's so cold it may not warm quickly either.",
"Depends. It used to always be from the heat of the radiator water (indirectly - blowing air over the hot parts of the engine or hot water pipes taken from the engine). I have had cars (e.g. Ford Escort) that have literal heaters inside the dashboard... electric coils that heat the air as it blows in."
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ew4ukf | Why do you need to press so many buttons to start a plane? Can’t there be just one button to start everything in sequence automatically? | Technology | explainlikeimfive | {
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"When you start a car, the twist of a key actually automatically activates many separate systems. First it powers the electrical system to many critical components. Fuel pump. Engine control unit. Ignition system. Then if you continue twisting the key it engages the starter motor, and starts the engine. You release the key and all of the systems keep the engine running. In an aircraft all of these critical flight systems are isolated on different switches, and often have multiple backups (fuel pumps, ignition systems, hydraulics, air pressure, different sources of power for the electrical system, totally separate electrical systems). There is a redundancy and level of safety here that lets a pilot troubleshoot and select or de-power systems individually in the event of a failure while in flight or on the ground. Hence the complexity of starting. It requires a certain order of operation to bring everything online to start a plane. EDIT: Some seriously good discussion here about aircraft. A couple of points to make. Are we talking about starting the engines only, or taking an aircraft from cold and dark to ready to taxi? I agree that FADEC systems allow an automated start. But even then you still have to at least turn on the battery master. And even if the aircraft could be fully automated, that wouldn’t preclude the need to check and verify that everything is working and set appropriately. Also, automated systems are their own system that needs to be monitored with the possibility of failure (MCAS). I’m not making an argument one way or another, thanks for the discussion. EDIT 2- One final comment guys. Many people have said this, and I will agree. A fully automated, one touch button start aircraft, complete with systems integrity monitoring is technically possible. And in small drones you can actually find this technology today. The question is, is this acceptable, is this safe, and how can we determine the risk going forward. Commercial air travel is by far the safest method of travel in the world today. It’s a really really high bar to even meet. Getting technology to match that level could be coming in the future, but it’s going to be a long and slow implementation.",
"Tldr: It's more or less a checklist to make sure all systems are working properly. Some of it may include adjusting the instruments on the dash so the readings are correct based on weather conditions and compass readings from the ground. Radio check on all the radios. Listening to the weather forecast and writing it down. Depending on the aircraft, you may need to prime the engine, start it up, check and make sure it acts as expected when you adjust things. Make sure back up systems are working well. Make sure all the control surfaces, flaps, evelons, rudder is working. Check the exterior lights work. Check to make sure all the sensors, radars, and other equipment is working. Hydraulics and back up hydraulics. Cabbin compression, emergency equipment. Navigation equipment. That's about all I can think of, but it's quite a lot. Almost every thing on a commercial plane is going to have main systems and back up systems. You want to check it all out before flying. Even after the plane starts moving you have to check a few other things, like the brakes and throttle.",
"Airbus pilot here. We have 2 switches to start the airplane, the first is to tell the computer we want to start the engine and the second initiates the start sequence. I flew Boeing before and they have a more complicated sequence, but without going into too much detail the Airbus way is just better. Feel free to AMA I’m off today!",
"Speaking from gliding plane experience which doesn't have an engine and yet I still have to do a 5 minute checklist. Part of the check list is just checking if the damn button works. Does the rudder stick move fully in all directions? Do the flaps move when I move the rudder? Does the brake work? Does the cable release work? Do all the instruments do their job properly? Is it pointing north? Does the radio work? I have to pull everything at least once. I have to put every instrument on zero, even if it's already on zero. I really don't want to be 800m up in the air and learn I can't steer right or that my landing flaps don't work. & #x200B; And gliding is easy compared to actually powered flight. Also I'm alone and not responsible for 200 people's lives.",
"In a car you're responsible for 8~ lives and there are not as many systems in play as a B737-800 for say (a car engine dies, you slow and stop; a plane engine dies, you now have uneven thrust on a vessel with hundreds on board and \"stopping\" means hitting the ground, however well you're able to do it), which can carry hundreds of souls. if you look through youtube for preflight checklists youll see how necessary each step is. one big thing is safety, make sure all your warning lights work (there's a test switch for all warning lights). the other is airline cost, you dont want to start your engines until you need them (fuel cost AKA cost index), and before that you need to make sure everything is safe to function in the event of a failure. some planes like the 747 can't even move until al 4 engines are running because if only 2 are running they would produce an unsafe amount of thrust to move around the airport to the workers on the ramp. so mostly it comes down to safety. and then there's redundancy. You can start or restart an engine with the APU, or with the bleed from an already functioning engine, or from electricity from either the apu, a generator, the battery, or ground power. with so many variables you have to check to make sure each is available to you in the event one somehow isn't. sticking with the theme of safety, you have to make sure your instrument readings are correct, setting the QNH (make sure your altimeter knows where the ground is), check that your settings are ready for takeoff (go full throttle for a second and make sure the warning sound beeps when you know you aren't set for takeoff) etc. a lot of this is programmed into the Flight management system (FMS/FMC) and in fact pretty much all of the flying is done by the computer once you reach the \"transition altitude\". but the onus is on you to make sure the computer is doing everything right, and you need to know how to solve a problem if one arises.",
"[Newer high-end airplanes]( URL_0 ) do have automated start sequences. Technically it isn't too difficult, it's just that it requires a computerized sequencer to operate all the switches and valves based on inputs from other instruments. When you have critical equipment run by a computer you have to go through a painful, long, expensive process to qualify the software and hardware. I work in nuclear. Software QA is similar -- usually easier to deal with ancient instrumentation than find something with acceptable software QA.",
"You want as much control over such complicated systems as possible, if only to be able to work through any in-flight emergencies if need arises. And, modern aircraft are quite automated anyway, just compare modern computerized cockpit to one from 1960s. Some aircraft had a separate crew member to just control/oversee the engines and other systems due to super high workload. It is still hard to fly a passenger liner compared to driving a car, bexause you have so many systems there (and often, most important ones are doubled, or quadrupled for safety, too)",
"If your car malfunctions/breaks down while driving, you can take it to a mechanic, or get a tow. If it's a plane that's flying, you have to fix it before you die. When flipping all those switches to start the plane, you're not just turning things on; you're making sure they work. If you find a problem, you can isolate its location; then either attempt to fix it, or abort the flight: thus preventing said problem from crashing your plane.",
"Think of it like a Velcro shoe and a laced shoe. The Velcro shoe just takes 2 steps: pull out taut and bring in the other direction. A laced shoe requires adjusting the strings and pulling taut, crossing and looping under, creating a loop. Then it’s winding one strong around the other, creating a gap, pulling through, and tightening while making sure it doesn’t come undone at the end. Both do the same thing, keep the shoes on your feet, but one is more complicated, gives more control to you, and is much more stable and reliable!",
"There could be, but it would probably make the aircraft much less safe. It would be pretty easy to program a computer to go through the normal cold start procedure, even accounting for conditions that would require a the procedure to be modified, perform pretty much every diagnostic check that a human pilot would. It would be 100% reliable, under 2 conditions: every sensor is giving the computer accurate data, and the thing was set up correctly (both by the programmers that made it, and the pilots that pressed the button). However, in the real world, you can never rely on both of those things being true. Having actual humans go through the means that even if technically all the numbers are right, they can investigate if something doesn't \"feel right\". This means they can catch edge cases that the programmers of an automated system might have missed, and also might notice if a sensor is giving bad data. Also, in the case of an emergency, it's vital that the pilots are aware of how every system on the plane works and interacts with every other system. By manually switching power from the battery, to the APU, to the engine generators, they're essentially reviewing how the plane's electrical system works, which could be the difference between a safe landing and a crash if there is an electrical fault in flight.",
"I remember listening to an NPR story about this a while back. The pre-flight checklist (and the general idea of a checklist as we know it today) was invented by Boeing after two pilots died in a 1935 crash of a prototype plane in Dayton, Ohio. The system failure occurred because the pilots had forgotten to disengage the gust locks prior to takeoff, which are only supposed to be active while on the tarmac. Basically, as others have said: even if a pilot thinks they know the switch is in the right position, the stakes are just too high to assume they are correct. Human error (or in the case of your original prompt: program error) is a thing, and hurtling through the air at 500mph isn't something that should be taken lightly. Hence the double checking of every function on board to ensure safety.",
"Don't you think it would be dangerous to have an airplane that can activate with the push of a single button?",
"Some good and really bad answers here. I’m an expert in process control, and to black and white answer your question, there is no technological reason why this is not possible today There technology is currently in use across many processes and industries across the world, and relatively simple to program and still keep the pilot at the front of control. On start up, the pilot would need to be retrained to observe a start up report in case of any anomalies and likely they would still 4 eye check that all systems are functional as intended. Whether this should happen would be a purely human factors discussion. It could be argued that a less manual start up sequence may cause disengagement of pilots, but the counter argument would be that a program can do the task quicker and with magnitude lower errors. An interesting discussion anyway but from you question, yes it’s possible.",
"I am an airline pilot, so am probably a good source to answer. I have not read up on any of the comment replies as I am off to bed. (ELI5) Anyhow, the actual turning on of the aircraft is very straight forward. In an Airbus, once you have the aircraft correctly figured, we basically turn one switch to \"start\" then select the engine master for that specific engine to on, if everything is working as it should the engine will start and we can do the same with the other engine. Unfortunately (or fortunately as I am still employed), there is a lot more that goes into getting an airplane set from a black airplane (powered off) to lift off. (ELI15) The very abbreviated procedure of us getting in a powered off aircraft to lift off goes something like this: Arrive at the aircraft, first on the slate is getting electrical power to the aircraft, we can do that by accepting ground power (plugged into the airport grid) or by turning on the APU - Auxilary Power Unit, which is a very small jet engine in the tail which provides power to an electric generator. Once we get electrical power on, the airplane takes a few minutes to do a few self tests of some systems etc... Once the aircraft has electrical power we will turn on our main source of navigation - 3 inertial reference computers which generally take > 7 minutes to warm up, if you are starting them from cold. Once those are set up, we will initialize the navigation computers telling the MCDUs we are flying from point a to b, and where we are starting. We will establish a communication from our computers through to the ground computer and request some performance and weather information out of these computers (called ACARS). This is usually the right time for one of us to go do a walk around, make sure the aircraft is not damaged, any instrument probes are not covered, access panels that should not be open are closed etc... At this time the other pilot can take a look through the log book, making sure the service checks have been completed on schedule, any required maintenance tasks have been completed and that there is no significant maintenance history we should know about. Once everyone has nested back into the flight deck we do a ramp check - or a geographical scan. Start at one side and verify every switch is in their correct position, or turn them on or off. There are many different switches from, fuel systems, air conditioning/bleed pressure switches, fire systems to be checked etc.. Once this scan has been completed we will request/verify our IFR clearance. How ATC allows us to fly from point a to point b, compare it with our flight plan and consider the weather, our performance and runways in use. If all is good and we accept the clearance we need to then load everything up into out navigation and performance computer called the FMGC - Flight Managment Guidance Computer. Loading the FMGC is a very structured process and you can generally go through it relatively quickly - especially if your box can upload the flight plan routing, if not you have to input everything. Following things all need to be imputed: Departure, Destination, Flt Number, Cost Index, Alternate, Routing between point a and b, stored routing, winds over every way point (bonus if uploaded), step climbs or descents, navigational aids, secondary routes may include a second runway, an engine out escape routing if in the mountains, your weights, centre of gravity, fuel uploads and alternate burns (which you have to confirm all add up) then your performance figures for take off and climb (the rest you can do enroute). Once that is complete the airplane is ready to go - you and your first officer (or captain) will have to brief what you're doing (take off, departure, anything non standard, engine out procedures and plan) etc, discuss any threats you may face and how you will mitigate it all. If no one has questions you now have an opportunity to say hello to the passengers and get ready for push back. If everything works okay and you don't have to de-ice next thing you need to do is get a clearance for push back after consulting the ground crew. If cleared you can start your push back and again because we're flying an airplane - have to run the before start check list. Move a few switches - insure a few systems are good to go and you're good to finally ask the guy you're flying with to \"light 'em up butter cup\". & #x200B; Whew - apologize for the long winded non proof read response. Just for the record during all of this we monitor fuel loading/cargo loading/cabin temperatures/delays/ATC flow etc... all of which is in addition to the above. Sometimes you have issues like the flight attendants noticing the water and waste have not been serviced, or you need to chase down a fuel truck etc... It's a great job, I love it - it's challenging at times but there is a shit load of managing to the job - the flying is the easy part (I had hard flying jobs in the arctic - airline world is about keeping the operation running smoothly. Thanks for reading.",
"I am no plane expert, but imagine as a Pilot, suddenly your plane is showing one warning light, and you don’t have anything else except one start button",
"Think of how many times in your life you have turned the key on your car and had it go \"rrr rrr rr rr rrrrr rrrr rrr\" or just be vaguely bad or broken. You very extremely do not want the engines on your plane to go \"rrr rrr rrr rrr rrr rr rrr\" so they have you do every step and check every step very carefully and make it so the plane can not stop and is not allowed to take off unless every part is good, compared to my highschool car which I had to start 5 times and then has the transmission shake like crazy at low speeds.",
"It's not just planes, most computer systems, factory plants and vehicles which are not made for the end user are a lot more complicated to start, maintain running (flawlessly) and shut down then a car. As an example I can talk a bit about my work in a candy factory. The plant to produce the candy slurry has an estimated learning time of 6 months, and then you're barely qualified to start it and shut it down, if nothing unusual happens. The process from the point of powering the controls up (pressing the power on button, so to speak) until everything is set for regular use takes about an hour. There's a similar gap in user accessibility between home owned PCs and servers used for companies and specialized tasks.",
"Part of it is the checklist aspect that others have mentioned. Also, it's kind of like why high end cameras have tons of controls while your smartphone camera has very few and does most of the work for you. Cars, and smartphone cameras, are designed to be easy to use in most circumstances. They are highly automated because that makes them easy to use. The tradeoff is reduced control, which means that when you encounter one of the circumstances that the automated systems can't handle well, you don't have easy access to controls for the individual subsystems, AND you probably don't understand them well enough to know what to change to make it work. In a smartphone or car, that's generally ok, because you can put the smartphone down, or pull your car off the road. On an airplane, it's not ok. The pilot needs to be able to directly control many different systems at a moment's notice in case something goes really wrong, and they have to be accustomed to directly controlling those systems, so that if they ever need to do it for real, it will come naturally to them. They might not have time to fidget. So that's the other part. Pilots need to be masters at controlling many different subsystems because a situation COULD occur where they need to assume direct control of one of those systems. Case in point: the two recent disasters involving 737 MAX aircraft. There was an automatic system to handle keeping the aircraft's angle of attack (how much its pointed up/down) at an optimal level, and the pilots weren't trained in how to take direct control of that system, and didn't have an easy way to bypass the automatic system (which malfunctioned) and assume direct control. Result.. two crashes, hundreds dead.",
"There are two points to this. If you are thinking of an old 172 airplane the main reason is it's from the 50s level technology. Sure improvements have been made but those carburetor piston engines need you to manually control fuel flow (more to do with airplanes encountering different air pressure at altitude which requires the fuel mix to be adjusted). Its old reliable technology but had a bit more human input. New engines that have digital controls are mostly just push button start. A computer takes care of everything just like your new car. Might be 3 switches, battery then fuel pump on then flick the starter and boom engine running. Separate switches for these things to be able to isolate them in emergency or just because they are not always needed. The rest of the time taken getting into the air is running checklists to ensure everything is running properly and if you are going IFR flying getting the clearance from ATC can also some time be a longer wait. The aircraft can be in the air very quickly if you need to and skip the checks. For example when I was on a red alert stand by for fire fighting we had to be airborne in less than 5 minutes from getting the call. As we are waiting at the look out tower for 8 hours a day we clearly are not sitting strapped in all day waiting so some of that 5 mins is just getting in. To make sure the aircraft is ready I ran the full checklist at the start of the day and basically just did the bear minimum checklist to get into the air. Typically in around 45secs to a minute to have the helicopter cold to airborne. In this case I'm trusting my previous full checklist and the aircraft hasn't been out of my sight all day. For less critical flying we do have turnaround checklists that ignore many items on the first start of the day checklist to get airborne quicker. Compared to flying IFR where more items are critical that they work so longer checklists I might be 10min on the ground before departing.",
"Pilot here. In a sense, a lot of the larger planes *are* \"one button starts\", in that when everything is configured correctly, you simply turn a knob or push a button and the start sequence happens automatically. The major difference between larger planes and cars is that, while cars can be started simply by the power from the battery alone turning over the engine, supplying fuel from the fuel pumps, and powering the spark plugs all at the same time, jet engines take a lot more \"oomph\" to turn over. They are far too heavy and need to turn at thousands of revolutions per minute before they gain enough speed to compress the air and begin the combustion process. Hence they are started with pressurized air rather than an electrically driven starter. This air is typically supplied by a smaller jet engine in the back of the plane called an Auxiliary Power Unit which is small enough that it *can* be started with an electric motor. This smaller jet engine outputs enough pneumatic pressure to drive the larger jet engine and begin the combustion process. However, when it is broken or disabled, they can be started on the ground with a huge cart that is basically a giant fan that blows air into the engine and can get it going fast enough to begin the combustion process. If you have one engine running, it can also supply the air to the other engine. And in the *extremely* unlikely event that you lose *both* engines *and* the APU in mid-flight, the airplane can pitch down and glide fast enough to use the air blowing through the engines to start the combustion process. Pretty cool, right? So in a way, when everything is working correctly, most larger airplanes are started with a two-button process- start the APU, then start the engines. The reason the airplane is so \"configurable\" and has so many buttons is primarily for troubleshooting and manually tweaking the systems in the event of a mid-air emergency. Unlike a car, when your engine quits or starts to overheat or something else, you can't simply pull over and coast to a stop. You need to be able to isolate the affected systems and toggle them on or off as necessary. Also, if a giant computer controls all the systems and the computer itself has a problem (*cough* 737 MAX *cough*) you want to make sure you can manually and directly control the individual systems. Boeing takes the majority of the blame for the MAX design, as well they should, but there was a lot that went wrong on the pilots' end of those crashes, too."
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ew5r1c | Why is “turning it off and on again” an effective troubleshooting technique? | Technology | explainlikeimfive | {
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"I saw this explained years ago by another redditor I can’t remember or find: Imagine you’re at a hotel and you call down to the front desk to ask for something. The person there answers your call, completes your request and then hangs up the phone, ready for the next call. But sometimes the are really stupid and get lost doing your task. They have ZERO initiative, so whenever they get a request that’s not formatted exactly right, get interrupted during a task or don’t get told to be ready for the next task they get stuck and can’t help with any new tasks until they get unstuck. Now imagine the hotel has 5000 thousand people at the service desk. One of them gets lost so is unable to receive new calls, this is fine as you still have 4999 people answering call. But every so often they get lost or stuck on a task and are too dumb on their own to go back to answering calls. So you wind up with fewer and fewer people available to answer calls until the call volume is higher than the number of people at the desk, which keeps shrinking. So you’re calling down but keep getting a “busy” response and can’t get through, and everyone else with requests is doing the same and the whole system is locked up. Then someone yanks the fire alarm. Everyone runs out of the hotel and the locked up staff are freed from their obsolete tasks . Then you turn it on and all 5000 help desk staff return to their stations ready to take calls."
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ewc48o | Why were Blackberries considered more secure then phones of other operating systems? Are blackberries still more secure then what we currently have ? | Edit; Blackberry as in the phone company/ OS. Not the fruit. | Technology | explainlikeimfive | {
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"Before the complete proliferation of smartphones, they used to be a thing that only high powered business/government people could afford and seen mostly as a productivity tool rather than a life partner. Many people didn't even buy them outright and got them through their work. Blackberry was the most popular smartphone in this era, so it invested a lot in being business/government friendly. Businesses and especially governments often have strict security standards for all their electronic devices, and the makers of Blackberry (RIM) invested a lot in meeting those standards. Those investments continued to be relevant to some businesses and governments even after they lost most of their market share. If you somehow bought a Blackberry today, it probably wouldn't be much more secure than any other phone, but you would have a better ability to install security software/features on it if you worked in IT for the federal government or similar.",
"it wasn't about operating system, it was about encryption that was used in devices for sms and calls right now the same or better encryption is achievable on free messengers like signal or wire your regular voice call and sms isn't really protected or secured by design, so blackberry used to add encryption to it in the past \"smartphones\" very closed in their ecosystems, so having backdoor or RAT on your device wasn't a real vector of attack right now with android being fully functional OS and iOS and android having millions of third-party apps in store, that might act as a RAT, OS hardening became a problem",
"BlackBerry was an early provider of Enterprise Management software that allows companies to lock down and remotely manage BlackBerry phones in the workplace. Businesses could install and operate their own management servers. This allows the company to brick a phone immediately upon employee termination among other things. Nowadays this can be done with/to any brand mobile phones."
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ewm3zz | How do radio waves travel to the opposite side of the planet? How do they overcome the curvature of the earth? | Does the signal simply pass through multiple radio towers? | Technology | explainlikeimfive | {
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"If you are asking about single transmitters, some types of radio waves have trouble piercing the atmosphere and “bounce” off. This allows stations over-the-horizon and out of line-of-sight to pick up the signal. You’re right that there are more complicated network methods to reliably get a signal to distant places. The signal can be picked up and re-broadcast (at the same or different power). The signal can be picked up, uplinked to a satellite, transmitted from satellite-to-satellite and then either re-broadcast by the final satellite or downlinked to a terrestrial station for broadcast. The signal can be picked up, transmitted by undersea cables and re-broadcast. Lots of network solutions are possible."
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ewmbvk | How do computers work? | Technology | explainlikeimfive | {
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"There are a *lot* of layers in between those two. It isn't a direct conversion from a binary number to an image. A CPU has two main components, the processing unit and the control unit. The processing unit can store small amounts of data, do basic math and number manipulations, and other sorts of calculations. The control unit does stuff like sending data between different parts of the CPU, controlling input/output to other parts of the computer, and implementing logic that approaches what we would call a program. CPUs also have a Bus, which is a bunch of wires that run in a parallel line that all the other components of the CPU attach to in order to transfer data from one part of the CPU to another. In the case of a 64-bit computer (which most modern computers are), that bus has 64 wires, meaning that it can move a binary number with at most 64 digits. The main effect this has is on the maximum size of a number (in either direction from 0, since binary can do negative numbers) that the computer can handle. CPUs also have internal mini-blocks of memory called registers, which can handle small amounts of data (in modern computers, 64 ones or zeroes per register). The x86_64 CPU architecture that's used on most desktops has four general-purpose registers, named A, B, C, and D (there are technically four more general purpose registers, but they generally contain important information you only mess with if you know what you're doing). The names get changed a bit depending on how much of the register you're using. If you're using the first byte of the register, it's called AL (A lower), second byte is AH (A higher). If you're using two bytes, it's AX. Four bytes is EAX. 8 bytes (64 bits) is RAX. Memory, also called RAM (which is different from storage space), is where your computer stores data it isn't actively using, or hasn't in the past few nanoseconds. Memory on modern computers is what's called byte-addressable (a byte is 8 bits, or 8 ones and zeros, and is the basic unit of data in a computer) meaning that you can think of RAM as a really long straight road with a line of houses on one side, and each house has its own address, and each house can hold 8 bits. If you want a number larger than one byte, say a 4-byte number (also called a long), you would say \"address 245 and the next three after it.\" Among the data in memory is programs, the data used by those programs, and data being sent from the CPU to something else, like video information being sent to your GPU. If you want to implement a program that adds two numbers together, you would need to write it in machine code (which is binary numbers that represent individual instructions like \"move data from this spot to this other spot\" or \"add the numbers in these two spots and put the result in some other spot.\" What we think of programming languages can be converted to assembly language (which is basically human-readable machine code) and then converted into machine code. Here's a simple example of a program that adds two numbers from memory, in the format \"MEMORY_ADDRESS: INSTRUCTION //COMMENT EXPLAINING\": ``` 0: MOV AL, [3] // Move data from memory address 3 to the AL register 1: MOV BL, [4] // Move data from memory address 4 to the BL register 2: ADD AL, BL // Add the contents of AL and BL together, and store the result in AL 3: DB 4 // Declare one byte of data, with a value of 4 4: DB 8 // Declare one byte of data, with a value of 8 ``` In order to make that program actually happen, we need to convert it to machine code. As it happens, instructions like MOV and ADD have binary number representations that vary depend on what they're doing. For example, there's a binary number that means \"MOVE X AMOUT OF DATA FROM MEMORY ADDRESS TO REGISTER. THE NEXT 4 BITS REPRESENT THE REGISTER NUMBER AND THE X NUMBER OF BYTES AFTER THAT REPRESENT THE MEMORY ADDRESS TO LOOK IN\". Those numbers are completely arbitrary and are chosen by the people that designed the CPU. Each instruction is made up of a few smaller mini-instructions that don't take parameters in the way that the instructions above do. From here, it's important to know about the system clock, the instruction register, and the instruction pointer. The system clock doesn't know what time it is, it's just a peice of crystal that oscillates at a known frequency, generating what's known as the clock signal. The pulses from the clock advance the steps of the mini-instructions in a similar way that a metronome advances the beat of a song. (as a side note, when you see a CPU listed as 3.2GHz, that means the clock pulses 3.2 billion times per second, or once every 0.3 nanoseconds). The instruction register is paired with a little counter that increments with each clock pulse. The instruction register is hardcoded (as in hardware programmed rather than software programmed) to have the binary representation of the current instruction (including the parameters) placed in side it, and to output the mini-instruction you need to do for that that instruction depending on the value of the counter. There are usually more than one mini-instructions per clock pulse, and usually with an IN or OUT part. If it's OUT, it means that the contents of the component referred to is sending data out to the bus, and if its IN, it's reading data from the bus. This is how data is transferred between components in the CPU. The instruction pointer is effectively just a normal register, but it contains the memory address of the current instruction. In order to execute the first instruction of the example program above (MOV AL, [4]), these are the mini-instructions that would happen: 1. INSTRUCTION POINTER OUT - MEMORY ADDRESS IN. This tells the Instruction Pointer to output its contents (which is starting at zero) to the bus, and tells the RAM controller to open up memory the memory address that it reads from the bus (which is zero, from the instruction pointer). 2. MEMORY CONTENTS OUT - INSTRUCTION REGISTER IN - INSTRUCTION POINTER INCREMENT. This moves the contents of memory address 0 (which is the MOV instruction itself) to the instruction register so that the CPU actually knows what instruction to execute. This also increments the instruction pointer, so that next cycle it'll look at address 1 and execute that instruction. These two steps are the same for any instruction, since they're required in order to know what the instruction actually is. 3. INSTRUCTION REGISTER OUT - MEMORY ADDRESS IN. This outputs the contents of the instruction register (but only really the part of it that contains the memory address to be loaded, not the entire contents) to the RAM controller. 4. MEMORY CONTENTS OUT - A REGISTER IN. This moves the contents of memory at the address that was loaded to the A register. At this point, the entire MOV instruction has been executed. The mini-instruction counter resets 0 zero, and the cycle begins again, loading and executing the next instruction in the program. Because the instruction has 4 mini-steps, each mini-step takes one clock cycle (0.3 nanoseconds), and there are only three instructions in the program (DB isn't an instruction, it's encoded as just data with an address in machinecode), that means our program will execute in only 3.6 nanosecond. This is why computers can do calculations so quickly. In order to display graphics, the technique really depends on the type of display and how you communicate with it. In the old days, before fancy GPUs, the CPU would calculate what needs to be on the screen and the videocard would translate that into something that the screen can speak. In the normal RGBa colorspace that we've used for quite a while, the computer sees the display as a grid of pixels, with each pixel having 4 bytes of data, one for each of Red, Green, Blue, and Alpha (alpha means transparency). This is where we get the term RGB, and why RGB colors are 0-255 (the range of value available in 1 byte of data). I hope this answers your questions, and I'd be glad to answer any followups. I'm sure I might have gotten a few details wrong, so anyone else feel free to correct me as I'm still studying this stuff. And OP, thanks for reminding me to change my major.",
"This is very difficult to explain briefly, but I think the most important part is understanding what a transistor does. They are essentially switches. By applying an electric current to it, you can change whether or not it lets a current on a different line through or not, a bit like a light switch that is somehow toggled on by the light of another lamp. You can then connect multiple transistors in clever ways to encode so called logical operations: you have several inputs and applying an input signal on them results in a certain pattern of output signals on their outputs. And cleverly combining those allows you to do basic math in the binary number system. You then take those basic math blocks and arrange them to more complex ones to do more complex math problems. Modern computers have billions of these transistors, allowing them to do complex math problems very quickly. As to how to assign things to 0s and 1s: it is essentially just a matter of convention. For example, you could decide to assign the four seasons to such numbers: Spring could be 00, Summer 01, Autumn 10 and Winter 11. How you assign this is up to you, it is just important that everyone agrees on the same thing. Similarly there are so called CPU instructions: in their most basic form they consist of 8 bits (a bit is either a 1 or a 0) and they tell the CPU what to do and the table for that has been created by the industry and set as a convention for everyone eventually (though not all CPU use the same instruction sets). This way a programmers can tell a CPU what it should do. Do some math, save something in memory, do some other math on the result, etc. And everything you see on the screen is essentially the result of a lot of math going on."
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ewo8bx | is there really a security difference between http:// and https://? Should I not browse http:// sites unless I’m in incognito mode? | Technology | explainlikeimfive | {
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"HTTP means that you and the website are sending postcards back and forth. Any mail carrier could just read the postcards, if they wanted, before delivering it to you. Sending your credit card number on a postcard would be horribly insecure. HTTPS means that you and the website are putting each postcard into a metal box and locking it, then passing those locked boxes back and forth. A mail carrier still knows that you and the website are communicating with each other, but all they can do is look at the locked box and shrug before passing it along.",
"Incognito mode will do nothing for your security. It doesn’t encrypt traffic to/from websites.",
"HTTPS encrypts your web activity, making it only visible to you and whatever service you are using, HTTP is not."
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j2ydd4 | When streaming services (e.g. Spotify, Netflix) let you download content onto your device, how do they make sure that you won’t somehow keep that content after you’ve unsubscribe from the service? In other words, how do they prevent you from stealing it? | Technology | explainlikeimfive | {
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"They encrypt the media files when you download or stream them. This is called Digital Rights Management (DRM). They limit how you can use the files you download or stream. They require you to use a supported browser (or their app) and to sign in to an account. Eg, They use [Widevine]( URL_0 .) on Chrome browser to encrypt the HTML5 video.",
"The files you download are encrypted. You need the app or website to be able to use them. Without the app or website, the files are complete gibberish and no other app can use them."
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j33hgz | how come my phone can run Playstation 1 emulators but the PlayStation 5 can't do backwards compatibility? | Technology | explainlikeimfive | {
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"They will probably let you buy psn versions of some games, which will be emulated. They want you to buy the games again. They don't want you playing discs that they no longer can make money on.",
"Who says they can't? They absolutely could, but it would cost them money to make while at the same time not making them any.",
"It has little to do with the performance capabilities of the hardware and everything to do with decisions made regarding how to make the most profit. Phone hardware is actually fairly powerful for how small and energy efficient it is. If the game developers want to port their game over to a phone, they can do that and pay a fee to Apple or Google for every game sold. Game consoles are a slightly different beast. In most cases, the console manufacturers don't make much money from the console itself. In fact, the consoles often cost more to make than it is sold for. They do this to get people to buy more games because the game developers have to pay the console manufacturer money for each game sold. This is called a \"loss leader\". In the end, they make more money from the fees paid by the game developers than they lose on the console hardware. Additionally, it takes a lot of money on the part of the console manufacturer to be able to ***guarantee*** backwards compatibility. They don't want to spend more money on a product that they are already losing money on especially when it will result in fewer game sales (which will cost them yet more money in lost revenue from licensing fees paid by the game developer). So, they shunt that responsibility off to the game developer which, wait for it, means they make more money from the game developer when a person buys the old game that was redeveloped for the new console. It's all about maximizing profits. I'm making up numbers here but the math basically works out like this: 1. Sony might lose $25 on each PlayStation 10 console. 2. Each console owner buys an average of 10 games over the console's life. 3. Sony charges the game developers $5/per game in licensing fees. 4. 10 games \\* $5 = $50, $50 in licensing fees - $25 in production losses = $25 net profit. Again, those numbers are made up out of thin air but they illustrate how \"loss leader\" systems can result in bigger profits. Incidentally, this \"loss leader\" paradigm is pretty popular. Printers are cheap but ink/toner is expensive. Nuclear power plants (when they were still being built) were sold by GE, et al at a loss so they could lock the power companies into expensive contracts for the nuclear fuel. Juicero was a marvel of electro-mechanical engineering that must have cost them a fortune but they locked you into a subscription that forced you to buy at least $40+ of product each week.",
"people that make phones make more money if someone thinks they can play ps1 games on their phone. people that make ps5s make less money if someone thinks they don't have to buy a ps1 to play ps1 games",
"Money and Quality Assurance. They have to pay the original game publishers for each game emulated. [Source]( URL_0 ) If they were to do a system wide emulation, they'd have to pay all of the previous publishers for games that most people won't use."
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j372mz | Why does wanting protect my data from large companies instantly mean I have something to hide? | Technology | explainlikeimfive | {
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"It doesn't, nor does wanting privacy from the government. This notion flips the whole idea of innocent until proven guilty on its head. It also subverts the right to privacy. That said corporations aren't bound by the 4th amendment like gov't is and in most instances you've implictly or explicitly allowed them to gather this information.",
"Get out of here with questions like this. You aren't wanting something explained to you, you are just trying to make a point. That's not what this sub is for.",
"It doesn't. It's a logical fallacy. Slippery slope (I think). Just because you want a thing, doesn't definitively mean you are doing anything else. What you described above is just a bad argument."
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j3isz0 | What is a subnet mask and how does it work? | All of the explanations I've had are very long and have words that I do not understand in the slightest so help would be highly appreciated | Technology | explainlikeimfive | {
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"Imgine you live in an apartment building and want to send a letter somewhere. How do you know if that letter should go to the post box outside the building, or in the mail slots in the lobby? Simple: you look at the address! If the address is the same as your address but a different apartment number it goes to the lobby, no need to bother the post office just to get the letter sent back. Essentially you use the subnet mask \"Niceland, cooltown 112, gray street 334, apt ???\" If everything up to the ??? match, the letter belongs to that \"subnet\", otherwise it is in a different building A subnet mask works the same way: assume you as an administrator control some chunk of IP addresses and want to split it in to two networks for \"reasons\", which often vary but make your life easier. By setting a subnet mask you can say \"these IP addresses live in this apartment building, and these in that one\". The actual devices on those networks can now correctly know where in the network other devices live: locally on the same subnet or on a different network all together."
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j3l7ou | How do the saws they use for hard casts not cut the flesh underneath? | Technology | explainlikeimfive | {
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"They don’t spin, they vibrate back and forth. Hard materials like plaster and fiberglass are brittle to the vibration of a metal blade. Human skin is malleable enough to absorb the vibration.",
"The materials used in casts, like fiberglass and plaster, are rigid but brittle. Your skin is super stretchy and can absorb a lot of vibration. Think of an earthquake: your rigid but brittle window can absolutely shatter due to the vibration of an earthquake, but nothing happens to you because your body is soft and absorbs the vibration. So the \"saw\" they use for casts is not a saw but a vibrating disc. The vibrations shatter the cast material but your skin absorbs them just fine. Of course, if the doctor jammed the \"saw\" into your skin it will absolutely get red and irritated. But as long as it stays mostly cutting the cast and not really jammed into your skin it doesn't hurt at all.",
"Same reason why you can shatter a diamond easily, it's hard. The harder and less flexible something is, the more brittle it is. Skin is very squishy, therefore it wouldn't be cut by the saw vibrating. A chainsaw on the other hand? Well, it'll take more than the cast off.",
"Put a saw on your skin, lightly, and only slightly jiggle it back and forth about a millimeter, never enough to actually make a tooth scrape against your skin. You see your skin just moving with it. Try the same thing with a hard surface, and it won't move with the teeth, so the teeth will dig into it. There you go, hard cast, soft skin."
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j3lr2t | what are the reasons some game engines for video games are “better” than others for certain games? Why do some have more bugs? I always hear “this game would have been better if the engine wasn’t so buggy”. | Technology | explainlikeimfive | {
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"ELI5: and engine is really just a toolbox that comes with tools in it. Most times those tools are good for general uses. Hammer, screwdriver, scissors. But sometimes you need tool not everyone has like vice grips, pipe wrench, utility knife. If you need those tools but only have general use tools, the project won’t go the same way. Maybe you get the results kinda close to what you wished for, maybe you just need to get the damn thing done and you talk yourself into accepting subpar. So maybe you borrow a specialized tool from a friend. But you don’t realize it’s a crappy knockoff and has a crack in it. You use it, maybe it works, maybe it breaks, maybe it looks like it worked but you go to use the project you fixed with that broken tool and realize now the project is broke too. Unity, Unreal, Crytek, they’re all great at many things. But none are great at ALL things. Mods can help, but not always. Oh and tool mastery matters. Like, can give me the most awesome proprietary 6 axis programmable CNC in the world, but I’ll barely know how to plug it in.",
"A video game engine is code that implements the \"core\" of a video game. You can conceptually split the game into the \"engine\" and the \"assets\" — the latter being images, sprites, textures, sounds, and even other code, all of which can be changed, added, removed, etc., without having to rewrite the engine. Of course, the engine can only do with the assets what it's programmed to. If your engine is based around sprites and tiles, you can't try to give it 3d textures, and maybe you can't have a sprite's movement end between tiles. In this way, the engine kind of defines the game. Different engines give different constraints that lend themselves to different styles of games. Somewhat famously, the Fallout 3 engine didn't support trains, [so the devs bodged it in as an NPC wearing a train costume]( URL_0 ). That could easily lead to some weird behavior that could have been avoided if their engine had trains. Maybe they didn't know they wanted a train until too late in the cycle; or maybe they reused an existing engine that wasn't written with trains in mind. I don't actually know — possibly both. As to why engines have so many bugs, there are lots of reasons. A few are, in no particular order: * All code has bugs, but the engine has its hands in every part of the game. If there's a bug in an asset, whatever that asset is for is broken, but if there's a bug in the engine it could break lots of different things & nbsp; & mdash; same number of bugs, but more things broken, so a higher chance of being noticed. * The engine is written separately from the assets, but has to handle any assets future artists and devs may throw at it (within reason). The engine code has to make assumptions and generalize, and sometimes the engine designers get it wrong. It's difficult to account for every edge case. * Adding features to an engine may undermine assumptions and generalization that were made earlier. It may mean rewriting a lot of existing code that wasn't general _enough_. There are probably assets that will break because _they_ made assumptions about what the engine could or couldn't do. * It can be difficult to fix bugs in the engine, because a change to fix one bug can affect lots of other things — things that at first glance don't even seem related. E.g., fixing a rendering bug could affect the timing of things in such a way that now an NPC AI goes haywire. * Video games are developed on insane timelines, and often QA suffers. Testing a video game is tricky, and involves time-consuming things like, \"run into every wall to make sure you don't fall through the floor.\" And when something changes with the engine or the map, that needs to be tested again. If time's running out, the studio is more likely to cut QA time than features."
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j3m4x3 | - How do tiny remote islands receive electricity and internet service? | I understand that power is delivered to places by an electric grid and that there are hydro electric dams or wind farms. I understand that high speed internet is delivered to homes the same way. But how do tiny, remote islands in the middle of the ocean have electricity or internet access? What's the source for power or for internet service in those places? I'm sure there's something obvious I'm missing but I can't wrap my head around it. | Technology | explainlikeimfive | {
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"If the island is sufficiently large, it will have its own power plant on the island. If the island is sufficiently close to the mainland or another large island, then undersea cables can connect power grids. But for the tiniest and remotest islands, it's mostly going to be based on small gasoline generators. You can buy a generator for relatively cheap that can generate electricity by burning gasoline. This is how people in a lot of remote places get their electricity for their homes, not just islands. It requires access to gasoline, obviously, but gasoline can be shipped in containers, you don't need direct access to power lines. On a remote island, cargo ships or maybe airplanes/helicopters will come once in a while to deliver whatever products people order, and gasoline will be one of the most important products delivered. Solar panels are an increasingly popular alternative, because they don't require constant deliveries of more fuel, and they're better for the environment, obviously. As for Internet, idk how that stuff works.",
"As another commenter said, power is usually generated on the island. If an island is small and remote, they may use generators. As for internet, there are a few ways. They could use satellite internet or they have undersea cables connecting them to a larger body of land."
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j3n15r | How is South Korea the forefront of cell phone technology (5g, soon 6g)? Why are other nations like the United States lagging behind? | Technology | explainlikeimfive | {
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"In Asian nations governments are deeply involved in infrastructure development. Not just communications, but electricity, roads, bridges. There are national development plans. In the US all these (and many other) are left to the market powers and private sector. There are no national development plans.",
"Population density is a factor here. South Korea’s population density and infrastructure is prime for 5g because of the close proximity to cell phone towers. The US has dense populations as well but they are spread apart and 5g needs towers at a much closer distance than 4g. Think of 5g as a mesh network with a bunch of towers close together.",
"Not only do the governments subsidize technology costs heavily, they also have true competition. In the United States, lobbyists have made it difficult for real competition to exist and without real competition innovation lags.",
"Probably because like Japan they have a highly skilled and educated workforce to develop high-tech products. They also have the machines and factories to produce them as well as having China on their doorstep to source components. Then they have a relatively rich population with the disposable income to buy them. Most of the population also lives in dense cities which makes it easier and cheaper to provide them with coverage. More so than a remote village in America or Africa for example. In Japan almost 80% of the population live in urban areas. In Korea it's over 90%.",
"A lot of people are talking about government and competition and evil corporations etc But honestly I think that when it comes to these huge infrastructure projects, the US's massive size makes it difficult. Korea is smaller than most states"
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j3oej7 | what is a DDOS attack and how can someone target your IP and cause your online game to lag in within seconds? | I play a lot of R6 siege and I’ve played games where my ping is in the 10’s of thousands even though I have very reliable internet. | Technology | explainlikeimfive | {
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"DoS: denial of service. From a single machine, send another machine a lot of data trying to overload it such that it can't or at the very least has trouble trying to respond to new requests. DDoS: distributed denial of service; same as above, but it's from multiple computers. Many times you are the recipient of a DoS, not a DDoS. Your public IP directly maps to your router usually, and then the router becomes overloaded and had trouble responding to your own PC's outgoing internet requests thereby increasing your latency to the point that you go offline. This is colloquially called being booted off. I hope that's ELI5 enough. Do you have more questions about it?"
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j3tfp8 | How can you play music while in a call and the other person not hear it? | Technology | explainlikeimfive | {
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"It's an echo cancellation. Your phone knows what's being played from the speakers and so it can subtract (remove) that before sending your voice."
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j3uts6 | Why do we measure the screen sizes in inches instead of ISO standard units? | I mean outside of the USA. Phones, laptops, monitors, TVs, all are measured and advertised in inches. Why? (Clarification: On ISO standard unit I mean meter (or cm). I just wanted to be PC.) | Technology | explainlikeimfive | {
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"Measurements are made in normal metric units, even in the US. Advertising is made up by ad agencies. They use actual measurements as little as possible, to try and get descriptions that sound more appealing. In they think inches are better, or rediculous diagonal measurements that don't even tell you the shape of the phone, that's what they go with.",
"I think it’s because with larger units you can round up and market the TV as larger than it is. For example, if a panel is 24.15cm=9.5in diagonally, you could round to 25.4cm=10in. Larger units of measure, and the assumption that we are labeling using whole number values, allows manufacturers to be less precise and eek out a little more in perceived value than you’re actually providing, without it being straight up fraud."
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j3w5d1 | how ARM CPU are different from regular CPUs | Technology | explainlikeimfive | {
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"There is no \"regular\" CPU - x86 is the most _common_ CPU, but there's no official designation. ARM and x86 are lists of instructions that the manufacturers say \"Our CPUs will be able to do < this list of things > , and you tell them to do these things using < this pattern > \" x86 and ARM have some things in common that they can do (like add some data, or move it from here to there), and some specific ones (that are too complex for ELI5) Historically, ARM has generally focused their designs to be a) smaller, b) consume less power, and therefore c) produce less heat - all qualities that makes them very good for things like mobile phones."
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j3ziq8 | My internet was being slow < 5Mbps so I called my ISP and they were able to send a signal to get it to 500Mbps, how does this work? | How or what could have caused the speed and what are they doing on their end to fix it? | Technology | explainlikeimfive | {
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"There are a whole range of things they might have done. \\- They might have just rebooted your router. Sometimes a simple reboot fixes things. \\- They might have assigned you to a different IP segment. Maybe the router you were going through is having issues or is overloaded. \\- Maybe they discovered that your router's config was wrong, and you weren't getting the speed you were suppose to be, so they re-sent down the router config and that made the speed faster. There are probably a few other things that they could have done, but those are probably the most likely.",
"It largely depends on the type of connection you have: cable, telephone (copper), or fiber. Each of these technologies has their own quirks and issues when it comes to speed. But there are a few things each of them has in common. Firstly, they're all managed by back-end software that optimizes your personal connection to their network. Small adjustments are being made all the time to ensure you get the best speed for the physical conditions leading up to your house. For the most part, these connections transfer data by a method known as FDM, or Frequency Division Multiplexing. It isn't a single channel coming in, it's hundreds or thousands of them, each carrying a little bit of information on its own specific frequency. Some of these frequencies (or 'channels' is they're known) are more effective than others, and still other channels are being actively interfered with by EMI- ElectroMagnetic Interference. EMI is everywhere electricity is used. Power lines, microwaves, cellphones, flourecent lights, margarita blenders- all of these produce enough EMI to affect the data coming through to your modem and throw the very sensitive data channels off their game. When this happens, the system- either your side, at the modem, or the ISP side at the back-end, notices that the channel is messed up, and drops it from active duty. Most of the larger EMI issues are always there, and so the weak channels are trimmed out in favour of the strong. This can affect speed, but it improves reliability. Besides, there are usually lots of extra channels that can be used as backups if a few of them aren't working out. Generally, these closed channels will come back up after a while, and be retested as they join back in. But sometimes theres a glitch, and they aren't reopened- ever. They just stay closed, and when your neighbor fires up their Blendermax4000 at 3am, even good channels can struggle, adding them to the 'closed' list. Over time, *all* of the channels can become closed; reducing speed to the point where the connection is barely keeping itself alive, if at all, anymore. When you reboot your modem (often combined mechanically with a router as a single unit) you are telling it to rebuild the active channel list from scratch. It reopens all of the channels, and waits for them to tap out from interference again. This is why rebooting a modem often works -at least temporarily- to restore dataflow, even if the connection itself is in rough shape. This same process occurs on the back-end, and so when you call into your ISP, they can re-optimize your connection through the same process, and ensure that your account actually has the system permissions it needs to get you your proper speeds. Most accounts are throttled in some way (for reliability, and to make sure there an incentive to upgrade) and the ISP checks to make sure you haven't been over throttled by accident (i.e. wrong account type on the back end) or intention (i.e you didn't pay your bill and got throttled to almost nothing so that you would call in). If it happens a lot, and you notice the issue clears for a bit before getting bad again, it means that your physical connection- the wires and such used for your internet- are in poor shape and need maintenance. If it happens sporadically (every few months or so and then clears after reboot) it's likely a software issue in the modem itself, or in the ISP backend. Firmware updates are the goto in solving these kinds of software issues. All in all, it's probably nothing anyone is doing specifically, and is likely just a natural quirk of the technology. Most ISP's are trying to address these issues all the time- reliability is a huge driver. If it happens a lot, it could be something physical, which requires a tech to fix. Otherwise, keep on keeping on.",
"Worked as a Comcast tech support close to 15 years ago so what I say might not even be how it works anymore. Your modem could've had a config file tied to slower tiers of service. Tech sees you're suppose to be on a faster tier. Updates account. Modem needs a reset to download correct config files and off you go or your modem was just being slow and needed a reset.",
"Lots of thing that could be happening here: 1. All the modems in your neighborhood use the same backhaul cabling but use different signal frequencies. If a signal is bad switching to a different frequency will fix the issue. 2. He rebooted the modem, if the modem had a fault rebooting could fix it. Rebooting also causes the modem to search for the best available frequency. 3. The modem's speeds are restricted by a configuration file. Updating the config file from his end can change your maximum speed. You modem may have lost the file, or been using a temp one and rebooting pulled the new update.",
"So, I’ve got a 100mbs fibre line with virgin media and I only get a maximum of 14mbs download on any device, PS4, pc, laptop, all connected via Ethernet cable. How do I increase this or am I missing something?",
"I can't say for other companies but for mine, the modem is provisioned for let's say 100, but if your plan is supposed to be 200, the way I get it to actually be provisioned to be 200 is to give it brand new instructions, and doing that will reset the modem"
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j40528 | why stock markets are still only open during business hours on weekdays now that most trading is electronic | Technology | explainlikeimfive | {
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"There are markets that are open 24/7. But professional brokers work only during business hours, so even if you can trade all the time the most high-profile trades will happen then. Also the closing hour auction result is pretty important for the value of derivates (wich need one clearly defined \"value of the day\")",
"Trading is now electronic but a lot of the trading is still being done with humans in the loop. This is because humans are much better at interpreting the information at hand and make the right decisions. Humans are of course not any good at high frequency trading but if you look at the trends taking more then five minutes it is mostly due to humans issuing the orders. And these humans needs to eat, sleep, see their families and relax. So the stock markets is only open during business hours so the traders are able to get some free time.",
"Because the market depends on people called *market makers.* These are people in a variety of positions that arbitrage positions between buyers and sellers of stocks. They are the reason that the \"spread\" between bid and ask prices are normally pretty tight - whichever way the trades are trending, there are some market makers trying to pick up a few pennies by playing the middle. Much of what they do is intuitive to the point that computer algorithms cannot really take their place. And since market makers are actual human beings, they prefer to come to work in the morning and go home in the evening. Lots of markets have \"after hours\" trading after the market makers go home, but if you trade in those periods you will notice that the bid / ask spreads are much larger than during the day, and you have to be a pretty savvy trader to not end up paying too much / selling too low during those after hours sessions."
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j40gz8 | How do credit cards work? | Technology | explainlikeimfive | {
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"Magnetic stripes are pretty simple from a technical standpoint: it's basically the same concept as tape cassettes: encode a magnetic field onto a strip of magnetic tape. When that strip moves, it will cause a changing magnetic field which induces a changing electric field into a nearby sensor, which has electronics attached to capture it and output the string of numbers/text on it",
"It's rather simple honestly. They run a tiny microprocessor system in that silverish chip. It basically contains nothing but your account information locked behind encryption. So it doesn't connect to the server, it only tells the reading device your account login information basically"
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j42mh8 | How did ancient civilizations know about planets vs stars? | Technology | explainlikeimfive | {
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"Planets move, stars do not. Over the course of a year, our angle to the planets changes significantly, and the planets themselves move. The same is not true for stars.",
"To the naked eye planets appear to move in paths across the sky, while the stars stay in the same position relative to each other. In the middle ages philosophers guessed that the stars and planets were attached to crystal spheres that were at different distances from us and moved at different rates. Which was a reasonable guess given that they didn't understand gravity. At least they understood that stars seemed to be further away than the planets. The name planet actually comes from the Greek 'planetes' meaning 'wanderer' The ancients new there was a difference between planets and stars but they didn't know the significance. For example they didn't know that the Sun was a star."
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j457v4 | How does a single speaker play the many different sounds and voices in a song or podcast all at once? | The way I understand it, cars or portable speakers only have one speaker so how do they play many different sounds at the same time? | Technology | explainlikeimfive | {
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"It doesn't make many voices, it makes sound that's the sum of all the voices. When the recording is made the mixer combines all the sounds into one aggregate signal.",
"When there are many sounds, they overlap and create a complex wave. (Even individual instruments/voices are usually complex, but even if you're just using basic sine waves.) You can't hear the difference, because there really isn't any, between all the separate sounds blending into the complex wave, and just playing the complex wave to begin with. So that's what the speaker does."
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j45dnd | When wearing sunglasses, and i'm looking at my phone, why is it... | Technology | explainlikeimfive | {
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"Sounds like they are polarized lenses. I can see how they work in my head, I just don't know the words, basically, your glasses are a fancy screen and your phone are a fancy screen, and when the lines that let light through from you glasses DONT match up with the lights on your phone, they black out. [heres a video.]( URL_0 )",
"Light consists of waves. Those waves can be up down or left right or any direction in between. What a polarization filter does is remove half of the light, I can't remember if it is the up-down or sideways ones. Now how LCD works... It contains a Horizontal Polarization filter followed by the LCD followed by a vertical polarization filter or the other way around. The LCD itself will turn the polarization of the light 90 degrees when it's \"on\" and does nothing when \"off\".. So when it's \"on\" light goes through the horizontal filter gets flipped in the LCD goes through the vertical filter and comes out. When the LCD is off it passes through a horizontal filter so only horizontally polarized light is there then the LCD does nothing to it and the vertical polarization filter blocks it. This means ALL the light from an LCD screen is polarized and you are wearing sunglasses that block light of a specific polarization. So in portrait the polarization of the light from the screen matches with the filter in your glasses and you see it. You turn the screen 90 degrees it does not match and you see black."
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j4br3i | How does an xray show that you have an infection? | Title is self explanatory. | Technology | explainlikeimfive | {
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"NAD but I believe the only X-ray that can show any form of infection is a chest X-ray. Typically a chest extra captures your lungs when clear vs if you have fluid in your lungs or pneumonia you will see what are called infiltrates or darker areas on film in patterns suggesting infection. They can also pick up granulomas which are from tuberculosis lung infections. Otherwise standard x-rays can’t show any other type of infection to my knowledge."
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j4evqc | - section 230 of the internet bill and what is being proposed to be changed | Technology | explainlikeimfive | {
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"Section 230 basically provides for liability protections for social media platform owners against things that are said on their platform. The proposed changes (I've seen many different variations proposed, but they all kinda revolve around the same idea) basically question the idea that social media comoanies are platforms at this point and at what point of seemingly selective curation and censorship does a platform (think minimal moderation, free for all) become a publisher (similar to the editorial page of a newspaper). The regulation as a whole is overly broad and vague, providing for \"good faith moderation\" without really describing what that entails or the limits thereof. Most of what I've seen in terms of rule changes more narrowly define what constitutes good faith moderation. For example: let's say Mark Zuckerberg likes cats, and hires people who are also cat people. Is it good faith moderation for a platform to remove or censor pro-dog posts? What about if they either modify their algorithms to promote cat posts and/or bury dog posts? What about banning people who are vehemently anti-cat (because they have allergies or just don't like cats)?",
"Casey Newton at The Verge provides a very clear/concise explanation, definitely not an ELI5 answer though! URL_0 It is often misinterpreted as requiring “fair” moderation efforts by platforms but that is not the case. It was put in place after a court determined that bc a platform had done some content moderation, it was liable for all content posted on the platform. Such a regime would punish companies with extra liability and actually incentivize them to not perform any moderation at all. 230, by limiting platforms’ liability, allows them to moderate without worrying about being sued every 5 minutes. It’s hard to imagine social platforms like reddit existing without 230 (although some have argued that we should remove 230 altogether, let FB/reddit/YT be sued millions of times, and let the courts decide what content they are/aren’t liable for). EARN IT and other legislation like FOSTA (in effect) attempts to remove 230 liability protections for select pieces of content like child porn and human trafficking. Most in the tech industry believe these laws do little to solve these problems and may actually make it harder to track criminal activity. Some versions of current legislation also try to bring in the (unrelated) issue of encryption into play as well. Edit: some legislation would try to enforce content moderation standards and ensure that rules are “fair” from a political viewpoint perspective. They propose making a committee at the FCC effectively the online “speech police” that has authority over platforms. Ironically, it is republicans that want to introduce this regulatory approach to the government restricting speech. This approach likely violates the first amendment as it involves gov’t agencies censoring private organizations’ decisions on what speech to host.",
"The original intent of the law was to protect internet service providers against lawsuits for using their service to post something using their service. They just provide a service, and are not liable for content sent through the companies service."
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j4jgca | how do online games work so well | Technology | explainlikeimfive | {
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"No, its called interpolation. The server is taking inputs, and video games still operate in \"ticks\". So the server is able to do math to determine which tick an input belongs. It has algorithms to help account for latency and such and \"smooth\" the differences in connection speeds. But this is how the game can operate at the same speed on a super computer as it does an i5 processor. Basically, if there were no interpolation, the game would just stack whoever has the fastest connection ahead of everyone else, making it useless to pay unless you have insane speeds",
"Input doesn't get \"sent to everyone at the same time\". When you provide input in an online game, you send it to the server. The server does whatever processing necessary to validate your input, then sends your new position back to you and anyone it's relevant to. What do I mean by \"anyone it's relevant to\"? Anyone who needs to receive your new position - they can see you on screen, or they're within a general area around you that it's important that you receive their position, or it's updating their position on a map, etc. If they can't see you and are far away, they don't need that update so the server doesn't send it as often (and your client uses interpolation to fill in the gaps). So you are unlikely to constantly receive 100-150 updates at all times. That said, those updates are pretty small, we're talking a bytes here....a few kilobytes at most depending on what is sent. So even if the server is sending out thousands of packets (let's assume a large average of 1KB per packet to 100-150 players) per second, that's still only a few thousand KB per second. Game servers are likely to have fiber connections (easily capable of hundreds of MB per second). ELI5 - Yes, internet is just \"that fast\"...but also the amount of data necessary for position updates is much smaller than you might expect."
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j4jrcu | Why do Monday - Friday "business days" apply to things that don't even need a human at all? | I was tryna cash out my earnings through Flex Pay in the Uber Driver app, which essentially just desposits my earnings automatically into my bank account. No human necessary. So why must I wait until the weekend is over to receive the money, just because it's not a business day, but it doesn't even require a human to do it for me. Since when do computer systems need days off? | Technology | explainlikeimfive | {
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"The simple answer is that a lot of systems which are needed to give you your money were not meant or built to be used 24/7. In the case of banks (which your transaction is handled by) it is done by means of a batch process. Banks are not primarily concerned with innovation, but instead prioritize reliability. Changing the batch processes to instant payments is therefore something they would like to do, but they will only do so when the reliability can be guaranteed. Handling of transactions between different banks, at least in Europe, is not done by the European Central Bank in the weekend. The system which handles these transactions, TARGET2, is just not processing any batches. The underlying reason however I cannot give you. The answer is therefore \"simple\" in the sense that the app you are using might support instant payments, but all other systems (your bank, the bank of Uber and the relevant central bank) also need to support the same speed.",
"It depends on how the payment or transfer is being processed. The money is in Uber's account at their bank, and since lots of people need to get paid very frequently, they probably batch these transfers through something called the Automated Clearinghouse (ACH) system, and at least in the U.S., I think these are mostly queued up while the sending institution is open and then processed overnight. A lot of direct deposits will have timestamps at like 3 AM for this reason. Technically, most transactions work this way. At my bank, for example, using your debit card on a Saturday will update your balance automatically, and the date on your statement will show it was initiated on a Saturday, but technically none of the transactions from the weekend actually post until Monday night. This means that if I go negative over the weekend, I can make a deposit on Monday and they'll apply the deposit to my ledger before my earlier payment is applied, so I don't get an overdraft fee. Uber probably operates the same way with a sweep account--all the payments you and others initiate trickle in over the weekend, then on Monday they're all paid out at once."
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j4jyug | Why are pant pockets positioned at the front instead of the side? | I notice this with jeans in particular, but I find most pants (men's or women's) have the pockets positioned at the front. There are some exceptions like yoga pants where I've seen pockets positioned on the side. | Technology | explainlikeimfive | {
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"The reason for this is functionality. If you take a standard pair of jeans and put the front pocket on the side, you wouldn't have room enough for back pockets. You would go from having four pockets to two. Or just silly looking pants if you added more pockets."
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j4k2xe | How do all the different programmers working on the same piece of software arrange all their different lines of code together to form the finished working product? | Technology | explainlikeimfive | {
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"Most teams use what's called a Version Control system which tracks individual changes to files (called \"deltas\"). When one programmer makes a change they push it to the VCS, the next programmer then either accepts that delta into their code and merges the two together then pushed the new version, or they ignore and overlay the version in VCS with their version. The exact process of how that happens is dependent on the mechanism of the specific VCS. With every change pushed to the VCS the code should compile and deploy to a test environment (either a local server/PC, or a remote server/PC) at which point it is tested. Any defects/bugs are reported back to the programming team to fix, then they push the fix to VCS and the process happens again until the software is ready to be deployed/delivered to the customer. Source: Am a DevOps Engineer",
"There are two important factors here: First, the code is designed to be modular, like puzzle pieces fitting together. Each programmer is responsible for a different part of the code, and they work together to design an interface by which the different components will interact with each other. Then, each programmer can work on their own code separately. Sometimes of course two programmers will be working on the same code together, in which case they will often physically sit together and write the code together (known as [pair programming]( URL_0 )). Secondly, source code management (aka version control, aka source control) such as Git. This software lets multiple programmers work on the same code together. Each programmer has their own copy of the code on their computer, and there's a version of the code on a shared server. Whenever one of the programmers makes a change, they can *push* the change to the main code on the server, and then the rest of the programmers *pull* the changes to their computers. If there is a conflict in the code between the different programmers, then they must *merge* the code before pushing it to the server.",
"Imagine if multiple people had to write a book together. First, you would have to agree on the overall theme of the book, and the overarching themes, then you would have to figure out an outline for the book and a table of contents for the different chapters. Once you agree on the general concepts, then you can split off and different people can write the different chapters. The key is making sure that two people aren’t writing the same thing at the same time. This requires coordination and communication. After the basic stuff is laid out, then minor tweaks and edits can be done by anyone, and it doesn’t matter that much if two people are fixing the same missing comma or whatever. It becomes a problem if someone wants to move an entire chapter or reorganize the structure of the book. That would require a lot of coordination beforehand."
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j4lqjz | Why do programmers actually have to write/type the codes? | I do not have any programming background, just curious about all these memes and jokes about programming. Basically what i'm asking about, is we can arrange things into a full poster just by using programs like Canva, Corel. We can create video out of other videos with Adobe After Effect, etc, but why do programmers actually have to write their code? Is it not possible to make a program that creates a program just by arranging things / setting up algorhitms like Corel, Powerpoints, After effect do? | Technology | explainlikeimfive | {
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"Yes, it's completely possible. This is what systems like Simulink (a control system modeller in MATLAB) do. But those programs are, themselves, programs and somebody has to write them. In many cases, you pick up a lot of overhead for using those kind of automated systems. The resulting auto-generated code may be larger or less optimized than directly writing it because it has to be more general and assume a lot of programmer intentions. Also keep in mind that, when programmers write in a modern language like Python or C, they're already working in an abstract environment. The only code that computers actually understand is assembly code, direct hard-wired commands to the processors. It is very rare today for people to code directly in assembly, although it still happens for some specialized reasons. Virtually all programming is done in higher level languages that are \"translated\" to assembly code by intermediate programs that were created for exactly the reason you suggest...to make programming easier.",
"As a programmer, commercially, you ideally want to write code that’s the fastest to develop in terms of programmer cost. In the mid-90s there were languages touted as “4G” where “anybody” could write a program. Some, like [HyperCard]( URL_0 ), although from an older origin, did allow some pretty sophisticated applications to be written. The 4G languages, as a rule, didn’t live up to their hype. Later, MS touted Visual BASIC, which was very popular in the stock trading/banking world. Plenty of programmers made money with it as it as pretty quick to knock up a bespoke program. But, software has a cycle of fashions. MS replaced this with C# which has a number of benefits and syntactically is familiar to many programmers. It’s also popular in trading for the same reasons. Note quite a few trading algorithms are initially written by the trader in Excel but to scale it, they often need speed or better integration into their “stock tick” for lower latency. At the end if the day, many programs fit different business requirements. If you want speed, a compiled language is a good choice. If you want a fast to market program, there are other choices that developers can rapidly deliver, such as the popular Python language. All languages have their pluses and minuses depending on the requirement and to get the best out if them requires specialists.",
"There are programs that do this to some extent, but there are usually more problems this way. Bugs that are harder to find and fix, super inefficient code, etc. If you need a unique programming solution, you're going to be writing it yourself anyway.",
"It is possible and it is exactly what programmers do all the time these days. Depending on your chosen environment, many common tasks are executed by using predefined libraries and APIs. Nobody is writing trivial things like opening a file or drawing an input field on a dialog box from scratch, that would be a huge waste of time. You still have to write a lot of code to combine all these elements in a very specific, unique way that is needed for your application.",
"What you're talking about is entirely possible. However, many actions in programming are specific, complex, and offer user interaction. You can do something like build a website with no coding experience, take SquareSpace for example, but if you wanna do anything super advanced that isn't built into the software you're going to have to code it yourself. Imagine creating a poster with some text in Canva - oh, except lets say Canva has no support to type text into your image. You can still make text, but you have to cut/paste it from somewhere else *or* draw the text using the shapes they provide. You can still make your poster with text but it's going to be slower, more difficult, and it won't look as good when you're done. Now compare that to software that natively supports text because someone put in the time to program in that functionality."
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j4mmn9 | How do jet engines create so much thrust? | Technology | explainlikeimfive | {
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"Basically jet engines scoop up a bunch of air, heat it up so that it's really hot, and then use that heat in the air to accelerate it to high speeds and send it out the back. This creates tons of thrust. To go slightly more in depth, jet engines are basically momentum engines, they use combustion to convert the chemical energy in the fuel to thermal energy in the air and then into kinetic energy as the air is accelerated. Since the air then has a ton of momentum going backwards, by conservation of momentum the airplane/engine has to get equal momentum going forward, which is basically what thrust is (Newton's 2nd Law). The equation for jet thrust is F = mdot*Veq, where mdot is the mass flow rate of the air, and Veq is the difference between the exhaust velocity and the forward velocity of the engine (there's also a pressure term, but that can be ignored to begin with). If you are interested in more specific details about jet engines, I would suggest looking into the Brayton cycle, the different types of jet engines (turbojet, turbofan, ramjet, etc.), and some derivations of jet engine thrust equations. Here's a NASA website with some more details on turbojet thrust: [NASA Website]( URL_0 )"
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j4rtzy | Why do streaming services like Netflix block VPN connections? | I understand that copyright holders prefer to distribute their content through different means depending on the location, I am confused as to why streaming services go to the extent of blocking proxy/vpn connections. Are they not incentivized to provide 'easy bypasses' to the geo-block such that they can remain in good terms with the copyright holders, whilst incentivizing consumers to choose their platform as they can easily access a wider range of content despite the block? | Technology | explainlikeimfive | {
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"> Are they not incentivized to provide 'easy bypasses' to the geo-block such that they can remain in good terms with the copyright holders They would not remain on good terms with the copyright holders. If the streaming service didn't make a genuine effort to prevent content from being viewed in locales where it's not licensed, the copyright holders would refuse to do business with them in the future. It might even be considered a breach of contract, which would allow the copyright holder to immediately remove all of their content from that streaming service."
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j4s532 | how does sawdust set off a smoke alarm? | So I was cutting some wood under a smoke alarm and set it off twice today. How is that possible? I thought they were set off by smoke or heat? Thanks! | Technology | explainlikeimfive | {
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"text": [
"Most smoke alarms have an internal piece of radioactive material that is separated from a sensor (like a Geiger counter) by a gap. Ordinary air does not deflect the radioactive particles, so they reach the sensor. The heavier smoke particles in air do deflect the radioactive particles, so the sensor stops receiving anything, and triggers the alarm. If particles of wood are entering the vent in the smoke detector, they'll interfere in the same way smoke would.",
"Some fire alarms use a photoelectric sensor: any blockage of light passing through air will cause the alarm to sound.",
"Some smoke alarms have two metal plates placed *very* close to each other, with an electric current running between them. When that current is interrupted, the alarm goes off. Apparently your saw dust was enough to block that circuit"
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j4t0jd | Why is it that switching the slots batteries are located in sometimes seems to rejuvenate their power? | Technology | explainlikeimfive | {
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"text": [
"What is actually happening is corrosion is building up on the metal connections. This corrosion is almost always present in some way or another, and this corrosion actually impedes the flow of electricity, but batteries that are still fully charged are able to “punch through” that layer of corrosion and let electricity flow. But as batteries get older, which leads to both a build up of more corrosion as well as losing some of their power, they start to lose their ability to “punch through”. But taking the batteries out, changing slots, and putting them back in again actually scraps enough of that surface corrosion off that the layer is thin again and the battery is able to punch through again."
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13
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j4vkhq | What is Overcurrent Protection? | Technology | explainlikeimfive | {
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"text": [
"It is a more accurate name for a fuse. The name comes from the way it protect any circuit from too much current being drawn. Typically this is due to a short circuit. Wires and connectors are designed for a specific maximum current draw. If something draws too much current through them they will melt and catch fire. So you want to protect from overcurrent by having something like a fuse which will cut the power safely before this happens. You do also have different kinds of protections in your fuse box such as undervoltage, overvoltage and earth fault protection. They protect the circuit from different kinds of faults."
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9
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j4xw7e | Why do fans come in 1 or 3 speed settings, but hardly ever 2, 4, or more speed settings? | Technology | explainlikeimfive | {
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"g7ofgoc",
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"text": [
"Low-Medium-High is an extremely common way for us to scale things, so it makes sense to build our products to mirror that preference. It's also a lot simpler and cheaper to have a 3-position switch than a six position one.",
"Electric motors can have their speeds varied in a number of ways depending on the price you want to pay. The main reason the fans you are thinking of have 3 speed settings is cost. To keep the price at a reasonably low level for both manufacturer and consumer, cheaper (and usually more crude) speed control methods are used. In most cases, low, medium and high are more than enough for most applications. Size is also a factor as the simple control you have on your fan is relatively compact. The slightly more expensive, entry-level commercial/industrial controllers can provide many more steps such speed 1 - 10 or whatever the manufacturer of the controller chooses. The next step up would be a variable knob, like a dimmer for your lights. Instead of the speed changing in steps, it changes based on where the knob is and the change is linear so the speed increases or decreases gradually as you rotate the knob. For more complex industrial/commercial applications that require precisely variable speeds, they will use a special electronic controller known as a Varible Frequency Drive (VFD) or Variable Speed Drive (VSD). They allow you to vary the speed basically from 0% to 100% and even above 100% (though not recommended). These are more expensive and more complex than the other controllers mentioned and require programming and set-up out of the box, they are NOT plug and play whereas the previous controllers mentioned generally are. You can have manual control of the speed using a knob or, more frequently, the speed is controlled automatically based on feedback from a control system, be that a simple sensor or a more complex automated system."
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j4yc9e | What is dialysis and how does it work? | Technology | explainlikeimfive | {
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"It's a process of purifying blood. Your blood carries oxygen and food to your cells and carries away the waste from the cells. The blood is then filtered in the kidneys. If your kidney doesn't work properly then your blood gets filled with waste products and so you must be hooked up to a machine which does what your kidney should do.",
"The kidneys get rid of waste products, maintain proper salt levels in the blood, and get rid of excess water. When they fail, dialysis takes over those things. The patient's blood is taken out through a catheter to got through the machine. It's a bit hard to ELI5 how it works without knowing how much you know about diffusion/osmosis. BUt basically, in the machine, there is a fluid that has the stuff you want to stay in the blood in the right concentrations. The blood flows next to this fluid, separated by a filter membrane. The bad stuff and excess water flows out of the blood, and good stuff flows back in. The blood then goes back through a catheter into the patient's body"
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j522jf | Computer Programming | Technology | explainlikeimfive | {
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"text": [
"\"Programming\", \"writing programs\", and \"coding\" mean the same thing. Really pedantic people might differentiate between \"scripting\" and \"programming\" but at the end of the day, it's all typing up instructions for a computer to follow. There are different programming languages that get processed in different ways, but again you're basically just typing out instructions for the computer to follow that end up accomplishing a desired task. Web development is a field that involves programming website functionality (and sometimes server functionality), but also things like designing the website, how it changes between mobile and desktop, etc.",
"A computer programmer codes stuff from a simple flip phone to the most advanced machines without them the world would look way different"
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j5b8qj | Why do some sites put a box when you press ctrl backspace when it should delete the entire word? | Technology | explainlikeimfive | {
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"g7r0jh8"
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"text": [
"Not all text boxes are created equal. Some are programmed to behave differently according to certain inputs. In this case ctrl+backspace will delete an entire word according to the way some are designed, and others will insert a \"box,\" which is a visual representation of a \"control character,\" a special non-text symbol that gets used for various purposes in different kinds of programs. When one of these boxes appears you can know that the way that the box was designed does not include allowing ctrl+backspace to delete a word."
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j5cu0g | What exactly do we have to do in a hackathon? | Technology | explainlikeimfive | {
"a_id": [
"g7r8ubc"
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"text": [
"Throw stuff together to create a minimum viable product. For example, there might be a hackathon for “digital beauty solutions”. Your team would then create an app that scans the user’s face and render different skin tones based on makeup, etc."
],
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4
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j5cyqt | How does almost 4k resolution games display on 4k a monitor. | Technology | explainlikeimfive | {
"a_id": [
"g7rav6u"
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"text": [
"Either the monitor or game itself or both will do what's called upscaling. A TV or monitor will generally be able to accept only specific resolutions, and a device sending video will only be able to send specific resolutions. The two devices will actually talk to each other when connected to figure out compatible resolutions. In the Xbox Sekiro specific case the upscaling is going to be done on the Xbox and output in 4k. For a PC upscaling will usually be done by the display if needed. In both cases upscaling works the same way resizing a picture in an image editor does. It just resizes every frame of video. There is a mess of different ways to do this but the algorithms all basically fill in missing pixels by picking colors based on the source image to fill in the gaps. The simplest way is to just pick the closest pixel and duplicate it which does use some pixels twice (called nearest neighbor scaling) and it looks terrible unless you are scaling by an exact multiple since pixels get duplicated unevenly. A better way is to combine multiple pixels and blend them to make a better approximation, mixing the colors together to get an in between color. Really smart algorithms can look at the original content and adapt the algorithm used to avoid problems like accidentally blurring sharp lines which can be a problem with interpolation. Waifu2x is a really interesting upscaling algorithm developed specifically to upscale anime style art which I'd like to mention. Similar stuff has been used to upscale retro games which tend to look terrible if upscaled since going from 256x224 on the SNES to 4k is a lot bigger of a jump than 1080p to 4k."
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j5d6db | How do shopping carts know when they're being taken out of the parking lot and to lock up? | Technology | explainlikeimfive | {
"a_id": [
"g7rapde",
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"text": [
"Magnets. Little antennas in the wheel lock pick up a certain magnetic field that is placed in the ground. Then they clamp down on the wheel when they pass over it. Its pretty simple and smart.",
"Where is this a thing? At least where I live shopping carts just have regular wheels and could easily be stolen."
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j5f67p | How do thermal cameras work? | Technology | explainlikeimfive | {
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"g7rldk5"
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"text": [
"Exactly the same way as any other camera, only the sensor in them is tuned to pick up light in the infra-red portion of the spectrum rather than visible light. Hot things radiate infra-red light, and the hotter they are the more of it they radiate, so the camera picking that up tells it how hot the parts of the scene are. Note that this is obviously a simplified explanation--in reality, the lens has to be different in a thermal camera or else its own thermal emissions would override what's coming in from the scene outside; but that's the basic idea."
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j5fymb | How are scientist able to see atoms? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The best way to visualize atoms is through the use of an atomic force microscope. This consists of a needle that has been sharpened to a single atom at the tip. This needle is connected to some machinery that detects where the tip is in space. The needle is then moved across the surface in question, like an ultra-thin sheet of metal. Since atoms do not like being close to each other, the needle tip is deflected every time it comes close to the metal sheet. These tiny deflections are sensed by the machinery it is hooked up to and sends it to a computer. A computer then converts this to an image, allowing scientists to visualize atomic structures."
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j5gp9b | Why does a laptop screen looks bad when it is taken with a camera? | Technology | explainlikeimfive | {
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"g7rxu7q"
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"text": [
"Your laptop screen is a grid of pixels, and your camera(unlike your eye) is also a grid of sensors. Unless you perfectly align each sensor to each pixel you will get Moire patterns."
],
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9
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j5hmlf | How does stores alarm know when to go off when someone tries walk out with a stolen item? | When walking out of a store and the alarm goes off because of stealing. How does the cash register send a signal to the alarm so, it doesn't go off when you walk out the door with a paid item. Also, if someone is to steal; for example, batteries out of the box. Would that be a loop hole in the thief alarm system....does the alarm goes off based on the bar codes on items? | Technology | explainlikeimfive | {
"a_id": [
"g7s0pru",
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"text": [
"There are RFID tags hidden in the item. When you walk out the security system notices the chip and sets off the alarm.",
"There are passive RFID tags in the packaging. These need to be deactivated at register, usually by passing the item over a surface that has a reader/transmitter in it. Once deactivated, the RFID tag doesn't transmit a signal when it passes by the scanners positioned by the store doors. If it's not deactivated, the RFID chip will transmit a signal when passing through the security scanner and trigger an alarm."
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j5kppx | Why do computers force updates on you at certain points? Like “screw whatever you’re doing it’s update time!” Kind of thing. | Technology | explainlikeimfive | {
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"The biggest reason is security. Security researchers (read: hackers) are constantly discovering new exploits which the developers must then patch. If given the option to, many users will just continue to postpone software updates indefinitely. This becomes a security risk for which the software developers are ultimately responsible, hence forced updates.",
"This often happens with computers managed as part of a corporate environment. I can tell you from experience with corporate IT systems that if they are given a choice to delay installing update, *most users will delay indefinitely*. This can prevent needed security updates from getting installed. And some times. you just need to say, as an IT administrator, that these updates are more important than the next ten minutes of your workday.",
"As some one in the software dev field here are my reasons. As a lot of people have mentioned security is a one. Having a user never update and then come crying and bitching to you when they get destroyed by a virus gets old very fast. Along with security is bug fixes. While people don't like the forced update they like random crashes even less. It's important that your product feel high quality, i.e it dose not randomly crash or have other undesirable behavior. So we would rather you get that once a month inconvenience of a forced restart than the inconvenience of a crash. The first makes us look annoying the later makes us look incompetent. Also the first is just a fact of life now, the second is something that gets you taking on Reddit about how shit our product is. We also want consistency, i.e we want all users to have the same experience. This can be important for a lot of reasons. The first is so everyone can use it. Lets say we are apple back in the day, and we just came out with faceTime. You love faceTime and want to use it with your apple friends. Well you are SOL they have never bothered to update so they can't use faceTime. This is not a good experience and will make faceTime adoption hard, but if we force update then everyone will have faceTime because it and all the underlying code you need for it were in the last forced update. This also helps us figure out what's working and what's not. Say the Foo function is not getting the user adoption we expected/wanted. Is that because the Foo function is bad, or is it that version 1.1.0 was bad? We fixed a lot of the issues in 1.2.0 but if you never updated you do get the fixes. So it is hard to tell if we have a issue in 1.2.0 or if it's just all the people using 1.1.0 giving it a bad rap.",
"If you go back in time to the days of heavily pirated Windows XP, Microsoft did not allow pirated copies to get Windows updates. However, this meant that they got no security updates, so they were very vulnerable to any exploits people found. This meant that it became very easy to create a Bot-Net from them. Essentially, viruses that just recruit your computer to do mass work like DDoS attacks or such. This is kind of bad press for Microsoft, especially since Mac had this reputation of not being prone to viruses (in reality, it just was a less opportunistic target, there was nothing that specifically made it virus proof). Nowadays, it is considered better to give the user some amount of time to try and get them to go along with updates on their schedule, but eventually just force it on them. Too many people would avoid installing them, and they would have significant security risks associated.",
"There's never a good time to run updates because most people only really have their computer on when they're using it and then turn it off or put it to sleep. Updates are important for security and stability fixes as well as providing new features, so in the end having everyone on the most recent version will cause less user headache with unfixable issues than the headache cause by the computer doing updates every now and then.",
"Why does Windows ~~do computers~~ force updates on you at certain points? ftfy If you don't like it, there are free operating systems that you could use that don't do things you don't want them to do, and if they do, you can just reprogram them so they don't.",
"\"Computers\" don't force updates on you--*operating systems* and the companies that make them do. Inconveniently timed forced updates were the last straw that pushed me from Windows to Linux, and I'm glad I made the switch.",
"The biggest reason is profit with the pretext of security. That forced update fits better with the software as a service Microsoft is pushing for, and it minimises their support costs. The whole deployed user base is forced to a version which you want and they have no say whatsoever about it. You can push things they didn't want like your new browser or the xbox core, or reset their privacy settings every week so they can't stop you collecting their data. All that makes you or saves you money. Linux has been considerably more secure without forcing updates, and chrome os is doing it right by using a dual partition system, where the updates are applied after you reboot without forcing you to do it mid work. This was a business decision not an engineering one",
"Because many users do not make updates when they have the choice. You have seen this with Windows XP. I know of offices where the updates were disabled on all workstations.",
"OP, use any other operating system than Windows and you'll never have to ask such questions again. Reddit will be HEAVILY biased for Windows and they'll try to justify its shitty practices such as forcing updates",
"That's exclusively a Windows thing. Part of the reason is because Microsoft tests updates on user's machines, so they can't be bothered to wait around for you to manually update.",
"It's not \"computers\" per se. It's Windows being Windows. If you don't want to be bothered by updates change to Linux where updates are always optional and require user input to apply.",
"People don't regularly update and restart their computer. They don't just download and force you to restart right now.",
"Because users are morons, and will defer updates indefinitely because it's inconvenient, never quite processing that getting hacked is going to make a 30 minute update look like a day at the park.",
"Ive been using the same SSD with Windows 10 on it for about 6 years now and have never been forced into a update. How are yall letting this happen?",
"That has literally never happened to me... however I shut my computer down at the end of the day and that’s what they assume the typical user does",
"Because otherwise people will never run the updates. If left to their own devices, the average computer use will assume they're fine because updates are an incredibly opaque and abstract subject. Those leaves those users open to security vulnerabilities and delays the adoption of new features. Some people assume they don't need the updates because they don't visit certain types of website, or because they don't engage in whatever risky activity, while other people assume that what they have now is good enough and running updates is just going to interrupt their flow. In short: people are lazy, and wildly overestimate their current level of safety while wildly underestimating their risk."
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j5n7dc | Why are games like MW so heavy (250GB)? | I don’t really understand what makes it so so heavy and there are some other games with better graphics that are less heavy. | Technology | explainlikeimfive | {
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"text": [
"Because they have lots of high res textures plus any videos e g. cutscenes. Their actual code will be tiny in file size in comparison.",
"Things like images and audio are tremendously huge files. Because of this they are almost always compressed to some extent. The issue here is that with compression always comes loss of quality with the higher the compression ratio the higher the loss of quality will be. Developers can choose how much they want to compress their data files to balance install size versus loss of quality. Games that are huge are often using a lower compression ratio.",
"Terrible awful no-good optimization. Don't let them tell you otherwise. Their game is not 10x the size of a large RPG due to having lots of high res textures in it."
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j5nlv1 | Why do bands with their own drummers sometimes use samples of drum beats? | Oasis and Slipknot have both used samples of the Amen Break. Why couldn't their drummers just play that rhythm if that's what they wanted? | Technology | explainlikeimfive | {
"a_id": [
"g7t3tlf",
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"text": [
"If it’s a specific sample (example: Bonham’s beat from When the Levee Breaks is often used in hip hop) you want the original sound because to recreate that beat you’d need very specific room mics and natural room reverb etc. so it’s easier to use the sample. Also a lot of people use samples because it’s been used before (tried and tested) and it may sound familiar to the listener if they’ve heard it before in other popular music genres. Hope this helps!",
"More often than not, they simply like how the sample sounds. Live drums sound rather different from samples, loops, drum machines, etc. Depending on the vibe of the song you're going for, one may be more suitable than the other."
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j5p6gz | How does a gaming system, CD player, etc. read a disc? | Basically the title | Technology | explainlikeimfive | {
"a_id": [
"g7tdl6p"
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"text": [
"It shines a laser into the disc. How the disc was cut or burned will affect how the laser light is reflected back, and then the optical drive can deliver the bit pattern that is indicated by the reflection. This is also why optical media lasts a very long time (nothing but light coming to contact with the surface) and why a scratch can damage an optical disk, because the scratch will also affect how the laser is reflected."
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j5rnlb | How can a speaker/headphone driver, which moves in a linear, 2-dimensional plane and should thus give equal sound all the way round the membrane, make the audio sound 3-dimensional? | If I wear a pair of headphones and play an FPS (first person shooter), I can hear that there is an enemy behind to the left. How is this possible if the driver/membrane is moving "parallel" to my ear canal? | Technology | explainlikeimfive | {
"a_id": [
"g7tv8tz"
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"text": [
"Your headphones are providing slightly different signals to each ear. Your brain assumes this is due to one sound source that’s physically distant from you at an angle. Your individual ears can’t sense direction, it’s only the combination of two, and comparing phase, that lets you locate sound."
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j5xqps | How does technology like an Apple Watch or Owlet Smart Sock track Blood Oxygen levels? | Technology | explainlikeimfive | {
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"text": [
"I’m not sure about the Apple Watch, but the owlet smart sock is a pulse oximeter. You have one side that emits light, and then a light sensor on the other side. You place a finger (or in the owlet’s case, a foot) between the light source and the sensor. Hemoglobin absorbs light, so they can tell the oxygen saturation based on how much light the sensor picks up on the other side of the finger (or foot).",
"Really all you need is 3 things to check o2 saturation levels. A light emitting in a known wavelength, a light sensor, and a program to read the difference between the emitted light and the light picked up by the sensor. Human skin isn't as solid as it seems. Light is actually scattered slightly under the skin. You can see this if you've ever shone a flashlight through the tip of your finger. It's also why we see people \"blush\". We can use this subsurface scattering in tandem with the fact that the molecule that transports oxygen around the blood (hemoglobin) gets more red the more oxygen it carries. From there we just shine a light at a specificaly known wavelength through the skin and let the hemoglobin absorb some light and reflect some back. We measure the difference between what was sent into the skin and what was reflected using some complex math and we get the o2 saturation of the blood in the system."
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j5yfv3 | how do those cassette tapes that plug into an aux cord work? | I cannot even think of a way that digital media can be transferred into cassette form to play in your car. | Technology | explainlikeimfive | {
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"Magnetic tape records audio as a change in in magnetic field strength of the tape. As the tape slides over the read head the changing magnetic field gets converted back to electrical signals. The aux cord adapters are remarkably simple. First thing is that the audio signal from the headphone jack is analog. The digital to analog conversion happens in the device playing audio. The cassette adapters just send the analog audio signal from the aux cord into an electromagnet that sits next to the cassette player read head instead of headphones. Changing electric field into an electromagnet makes a changing magnetic field.",
"The cassette part of the unit contains an electromagnet which imitates very, very well the same kind of signal generated by tape passing over the cassette player's play head. It is entirely analog.",
"Well it's funny you ask. I just watched [this]( URL_0 ) video that explains it. Basically the same head that is in the tape player is also in the cassette. It's like the one on the cassette is set to record (write) and it is creating the \"signal\". Just like if you were to record a song onto a tape. The one in the device that is playing your music, is set to play (read), just like normal. The cassette is writing info just as the player is reading it.",
"Technology connections does a great video on this subject. Its actually pretty simple. The read head of a cassette player converts the magnetic field on the tape into a analog signal. The cassette adapter has another head thats like a record head. The record head works like the inverse of the playback head converting the analog signal into a magnetic field. It is just emulating a tape. That aux cord only carries analog signals do the digital to analog magic happens in whatever device your playing back your files from.",
"Oh this is real simple. First off, the aux is analogue, not digital. That analogue signal is converted into a magnetic signal by the cassette tape. And there really is not tape in the cassette. Instead, there's a little device that matches up with the tape head - that's the part that normally reads the tape. So this little device changes a magnetic field that is picked up by the tape head just like it would a normal tape. The problem with these devices is that they tend to magnetize the tape head. This is bad for all subsequent tapes that you play. A magnetized head will partially erase any actual tape you play. You may not notice at first, but after a few dozen plays, you will notice a loss of high frequencies as the tape is repeatedly slightly erased. To prevent this, you need another cassette called a 'demagnetizer', and you should use it before putting any other tape in the player.",
"So I think it's worth noting that by the time the signal has reached the aux cord, it's already been converted from digital to analog. Our ears are analog, so any music we can hear is also analog.",
"actual tape is magnetic. cassette player has magnet sensor. More magnetic = louder. aux jack = electricity. More electricity = louder. moving electricity in a loop = magnetism. Aux jack -- > electricity -- > magnetism -- > magnetism sensor -- > loudness Digital music works entirely differently, but it goes to your aux jack at the end of the day, which is analog.",
"If you look at the business end of the tape adapter you'll see a metal rectangle with a rounded end in front, it's the exact same kind of thing that you'll find in a tape player. It's a cassette read head that is electrically attached to the headphone output of your device. The analogue signal that would normally drive an electromagnet in the speakers in a set of headphones instead drives the electromagnet in the cassette head. That changing magnetic field is then picked up by the cassette player's read head, and fed into its amplification circuitry.",
"There is an audio head just like the one in your player. It has an audio cable connected to it. There are some gears inside to trick the player into thinking that there's a tape inside. The heads in the adapter and player touch and the sound is magnetically transferred between them.",
"There's a magnetic field sensor in a cassette player. That normally reads magnetically charged tapes. There's another one, seemingly identical to it, in a cassette-adapter, except this one will be magnetically charged from the analog voltage coming from your music-playing device when plugged in. These two sensors come in contact; one reads the varying magnetic fields while the other produces them."
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j60tyx | How do 3rd party sites download youtube videos? | I know a bit of coding including very basic html, but how do sites, given a youtube videos url download that video? | Technology | explainlikeimfive | {
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"They request YouTube to watch the video, buy they instead send the actual file to you, it’s actually pretty trivial to do, the easiest way is finding the actual video URL (which is not the YouTube link) in the webpage and using a get request to download it. You can pretty easily write a YouTube downloaded with just some JavaScript code to find every < video > tag in the page and get the source"
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j60x54 | Why is 2.4Ghz Wifi NOT hard-limited to channels 1, 6 and 11? Wifi interference from overlapping adjacent channels is worse than same channel interference. Channels 1, 6, and 11 are the only ones that don't overlap with each other. Shouldn't all modems be only allowed to use 1, 6 or 11? | Edit: Wireless Access Points, not Modems I read some time ago that overlapping interference is a lot worse so all modems should use either 1, 6, or 11. But I see a lot of modems in my neighbourhood using all the channels from 1-11, causing an overlapping nightmare. Why do modem manufacturers allow overlapping to happen in the first place? Edit: To clarify my question, some countries allow use of all channels and some don't. This means some countries' optimal channels are 1, 5, 9, 13, while other countries' optimal channels are 1, 6, 11. Whichever the case, in those specific countries, all modems manufactured should be hard limited to use those optimal channels only. But modems can use any channel and cause overlapping interference. I just don't understand why modems manufacturers allow overlapping to happen in the first place. The manufacturers, of all people, should know that overlapping is worse than same channel interference... To add a scenario, in a street of houses closely placed, it would be ideal for modems to use 1, 6, 11. So the first house on the street use channel 1, second house over use channel 6, next house over use channel 11, next house use channel 1, and so on. But somewhere in between house channel 1 and 6, someone uses channel 3. This introduces overlapping interference for all the 3 houses that use channels 1, 3, 6. In this case, the modem manufacturer should hard limit the modems to only use 1, 6, 11 to prevent this overlapping to happen in the first place. But they are manufactured to be able to use any channel and cause the overlap to happen. Why? This is what I am most confused about. | Technology | explainlikeimfive | {
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"WiFi is not the only technology using the 2.4GHz ISM band. It shares it with Bluetooth, microwaves, radars and a load of other consumer electronics such as garage port openers, two way radios, remote light switches, weather stations, etc. So it may not be that the three channels are the best ones for a specific environment. For example if you have a weather station that happens to send its date back to the receiver on channel 8 then it may disrupt channel 6 and 11 but leave channel 5 and 1 open to be used by two networks. And you can not force everyone to use the same channels regardless of technology because the different radios have different bandwidth and therefore different channel spacings. The weather station might have chosen a frequency close to channel 8 because that would allow them to have four different weather stations work in the same area without disrupting each other given a bit closer channel spacing then WiFi.",
"even if you only allowed certain channels such as 1, 6, 11 to be used. how can you guarantee that the homes in that neighborhood would use them in the fashion that you described? and what if there are wayyyy too many people with routers? now since there's only 3 channels to choose from, there's a higher likely hood that any two adjacent houses uses the same channel. anyways, most wifi routers are smart enough to pick the best channel to use and can change them from time to time. it's like youre designing a bathroom with 5 urinals. the ideal situation is to have people only use urinals 1,3,5. and 2,4 if 1,3,5 are occupied. but if instead you designed with the same spacing but only have 1,3,5 you've inherently added a bottleneck and now have caused people to wait, when they could have used 2,4 in the first scenario. similar thing to routers."
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j637do | Does my GPS watch emit anything hazardous? | Technology | explainlikeimfive | {
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"No, GPS devices receive a signal it does not transmit anything. You are exposed to the signals from GPS satellites no matter if you own a GPS device or not. To answer your question, no GPS signals do not effect you in any measurable fashion.",
"Think of your GPS watch as a catcher’s mitt, you can only be harmed by the ball; not the mitt.",
"A GPS device doesn't have to emit anything. The emissions are coming from the satellite network, and all your watch does is listen to those signals. It should be about as dangerous as a calculator, and much less dangerous than a cell phone."
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j64zvb | What’s the difference between a png and a jpg | Obviously there is some type of difference, otherwise there wouldn’t be two different image types, but I’ve never been explained what the difference is. | Technology | explainlikeimfive | {
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"They use different compression algorythms. Because of this JPG images lose some quality during compression to make them \"lighter\" (less MB), while PNG images don't lose quality. They are a bit heavier as a result though.",
"The type of compression used. PNG uses a lossless method. All the information is still there, just saved in a more efficient way. JPG uses a lossy method. You lose some information, but JPGs take less space. It's very noticable when the image includes some text. You'll note some compression artefacts around it.",
"As a general rule PNG handles large areas of flat color (think cartoons and similar drawings) better, and JPG handles photo-real images better. There will of course be some exceptions to this. PNG also allows for transparency which makes them useful for certain things you can’t do with JPGs (irregular shapes, frames, screens, etc.).",
"PNG is \"lossless\" - there's no compression or loss in quality from the original source file. It also allows for fancier photo editing (having more advanced color scales/palettes, allowing for different transparency settings for the background of the picture, etc.). But, it tends to be a larger file size. JPG is \"lossy\" - it *does* compress a picture which can have an impact on the quality of the image. That difference isn't always so noticeable to the human eye, though, it all depends on the picture in question. It's not as diverse as PNG as far as how you can fine-tune the picture quality, but it does usually have smaller file sizes."
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j66y9s | why does music sound so different through headphones compared to listening in your computer or in your car? | Technology | explainlikeimfive | {
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"3 things, first is that bigger speakers can push more air so they can recreate more of the low end than smaller speakers in headphones can second is the space, headphones directly put the sound in your ears. Where as speakers in a car, some of the sound goes to your ears but some of the sound also reflects off the surfaces in the space your in before hitting your ears and that can change your perception of the sound. If you've ever clapped in a large empty space and heard the reverb or echo that's one way the space can change the sound. And third, which is related to the second. The way sound moves, it moves as a wave out in every direction from the source. So sound from the right speaker moves out in every direction and when it hits your right ear, some of the sound is still moving and hits your left ear. So both your left and right ear hear what's in the right speaker. But in headphones you only hear the right speaker in your right ear. So this also effects the perception of the sound"
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j68kqf | How do ISP’s change internet speeds? | Let’s say I have a 100mbps internet connection. I call the ISP and pay extra for a 200 mbps connection, and it gets faster with no new hardware. Does someone turn a knob somewhere? Thanks. | Technology | explainlikeimfive | {
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"Former Tier II internet tech support for a small ISP that didn't have it's shit together checking it! Regardless of if you're connected via fiber, ethernet, or cable modem generally speaking the larger network you're connected to is set up kind of like a tree. Each end user household (individual apartments, houses in a neighborhood) are the leaves. Several leaves are connected to a twig, which then connects to a branch, which may meet up with other branches and ultimately leads to the truck (the whole rest of the internet). The \"twigs\" that connect several \"leaves\" are usually smaller pieces of equipment that aren't terrible expensive and literally just bring many connections into a single line. They pass this on to \"branches\" that have larger, more expensive equipment that is programmable. An entire apartment high rise wired for cable modems may have one \"twig\" per floor feeding into a single \"brach\" that controls all of the cable modems in the building. Now on to the nitty-gritty on how someone actually sets bandwidth for end users! For ethernet networks the process is relatively straightforward. The \"twig\" pieces of equipment are usually ethernet switches, relatively cheap pieces of equipment that have one or two ethernet ports \"in\" and a few dozen ports \"out\". [Here's a good example if you want to know what they look like]( URL_0 ). When the network is initially being built in the engineers program these switches and carefully record which unit or home is connected to wich port (and usually label the actual cables). Usually the programming on these switches includes several files specifying how much bandwidth a port should be allowed. When a customer moves in or changes their bandwidth package it's just a matter of telling the switch that they're connected to to operate with the desired bandwidth specification file already running on the switch. Most big ISPs have this automatically linked to their customer service software so when a person in the call center hits a button confirming the customer bought a particular bandwidth package the switch updates to reflect that. The ISP I worked for did not have it's shit together, so my coworkers and I would manually log into the switch via a command line interface and reprogram the customer's port to use the specified package. Cable modem networks are somewhat similar, with a few key differences. In a cable modem network (also referred to as DOCSIS) all of the \"twig\" equipment isn't necessarily remotely programmable. Instead, the \"brach\" hardware is where the action happens. This piece lf equipment is called a CMTS, or Cable Modem Termination System. These bad boys talk to all of the modems on the network and can do things like monitor signal levels and even reset them remotely. A CMTS tracks all of this by the cable modem MAC address, which is why the Comcast rep with often have you read the information off of the label on the modem. Setting bandwidth on a CMTS is accomplished in a similar fashion to on an ethernet switch. Several bandwidth package files are programmed in ahead of time, but instead of setting a customer's port to one of these files their modem is set based on their MAC address. Each CMTS has a huge chunk of code on it that lists the bandwidth settings and then a huge wall of \"give this MAC address this package, give that MAC address this package\". Just like with ethernet, ISPs that have their shit together have their CMTSs linked to their customer service software so the file is updated automatically when the sales rep completes an order. If not, a person needs to connect with the CMTS and manually edit the programming to specify that a certain modem should operate on the desired bandwidth package.",
"It's literally just a setting. Back in dsl times, your max speed could depend on a lot of things. I would *always* turn up the speed to max stable speed for our customers, no matter their plan. With fiber, it's just a setting. Either \"check this box for this speed\", or just configure it on your own.",
"They just lift a data rate cap that their system puts on your service. It's all in a database, and the customer service rep selects a button for the new cap. That information goes to another part of the ISP's system that controls your connection, which then allows 200 maximum instead of just 100. They really can set it at whatever they want. One time they had to come out and replace my modem when I wanted higher service because the old one couldn't handle it. But they still had to make their change at their end to allow the extra speed.",
"Your speed is artificially limited by the ISP's piece of equipment on the other side of the wire from your modem (be it DSL, cable, fiber transceiver, wireless transceiver, whatever). Software tracks the amount of data sent to you over time, and when the amount exceeds your limit, the device will briefly take your data hostage and hold on to it for a short amount of time, rather than immediately sending it on to you. The server you're downloading from is looking for acknowledgements from you -- your device will periodically tell the server how many packets of data it has received. When your ISP throttles your data rate, the server notices that it sent 100 packets but you only got 80 of them so far. Based on this, the server now knows that you can't handle data at that speed. So, the server starts sending data to you more slowly. At some point, the server and your ISP balance out -- the server sends data just below your limit, and your ISP stops delaying your data. Turning on more bandwidth is just your ISP instructing their hardware to allow more data through."
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j68mwq | How does a smart scale determine your water percentage, amount of muscle weight and visceral fats by just standing in it? | Technology | explainlikeimfive | {
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"You notice how they have metal plates to put your feet on? Thats so they can run a small electrical current from one to the other, passing through your body. They measure the resistance (impedance) and use that to determine how much body fat and water content you have, as both will change how the current flows through your body.",
"As far as I'm aware, they don't. The rationale for these scales is that they should be able to run a small electric current into one of your feet and then out the other and measure differences in your conductivity at different currents and voltages. The current would have to go through your pelvis so it seems reasonable that visceral fat would be close enough to the current to affect it. But the measurements are skewed in a much more significant way by how damp your feet are, how much of your foot makes contact with the.. contact on the scale. So any result that the scale gives you is a guestimate at best and purely based on your height, weight, and gender at worst. As far as I'm aware, the only way to get accurate readings of your fat versus muscle is with hydrostatic weighing."
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j6j3jg | What is a proxy server, reverse and forward types? | Technology | explainlikeimfive | {
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"It's like when you want to tell a boy/girl that you have a crush on them, but instead of telling them directly, you tell your best friend to tell them.",
"Proxy server: A machine which passes on (typically HTTP) requests on behalf of you, the client. Forward proxy: You are asking the proxy to forward your requests to another server that you specify. Keeps the client anonymous since the requests only come from the proxy. Reverse proxy: You are sending requests to a server, but internally the server passes the request onto another server without your knowledge. Keeps the internal servers anonymous since only the proxy handles the internet connection."
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j6k9wo | Why does applying pressure to an led screen cause it to warp and show green lines and shapes? | Basically exactly what the title says. Why when I press on my laptop screen does it seemingly warp and make weird shapes and colors. | Technology | explainlikeimfive | {
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"There's a white light in the back of an LCD called the backlight. LCD is short for Liquid Crystal Display. Inside the display is something called a TFT - Thin Film Transistor. The TFT uses electricity to magically change the color of the liquid, this creates pictures. When you press the screen, the liquid moves around and this interferes with the magic color changing which produces puddles or splashes of different colors. The TFT is a grid, so possibly the green lines you see are a result of the TFT electrifying the crystal juice."
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j6l51c | Why haven't we created machine that produce food from water and sunlight like plants? | Technology | explainlikeimfive | {
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"We don't know how. Making an artificial plant that turns water and sunlight into food is really hard. Right now, its way easier to just grow more plants than it is to invent a machine that can do the things that plants naturally do.",
"Because nature has had billions of years to perform countless experiments with zero budget concerns We’ve been at it for maybe a few years",
"Because then you’d be eating the machine?plants are the food... or are you meaning like fruit bearing trees?",
"Plants don't produce food from water and sunlight. They require a variety of nutrients and such, plus CO2 and oxygen. That aside, humans evolved to eat large and complex organic molecules. In fact, we evolved to eat the molecules produced by plants. A machine to produce these molecules would require a fair amount of energy and complex many-step chemistry. Why bother?"
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j6mo0n | How are well-known piracy websites such as piratebay still up and running despite offering illegal services? | Technology | explainlikeimfive | {
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"> offering illegal services Are they? Torrent trackers don't host pirated content, they just let your computer find ones that *do*. That in itself isn't illegal (or at least wasn't/is a grey area in some countries). Plus, torrent and \"shady\" file sharing sites lease servers and domains in backwater countries that 1. have big holes in their internet and/or copyright laws allowing for these sites to operate legally 2. are a complete PITA to pursue legal action in from a different country So basically it's a whackamole game of copyright holders struggling for months/years to get traction to get a server shut down - only for it to spring back up from a fallback location in hours.",
"They do not offer illegal services. The services they do provide may have become legal in some countries but not in the countries they provide their services from. This is nothing different then having people go across the boarder in order to gamble, drink, have abortions, smoke pot, etc.",
"Many of them are hosted on other countries servers and using their infrastructure. Often times it’s the smaller 3rd world countries. Since they are out of country, it makes it hard for the US to do anything about them. And since they may be run through a third world country, the government there may not care or may not have the resources to do anything about it.",
"It basically boils down to it being nearly impossible to nail them down. The entire website can be stored on a single thumb drive. Combine that with the relative ease of shifting server hosts and using hosting services not based in jurisdictions where law enforcement can prosecute them and finally that they don’t host the pirate material themselves, it makes it super difficult to actually shut them down for any length of time. As long as there’s someone, somewhere willing to host the website, it’s very difficult to kill it."
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j6oxu3 | How do speakers make specific sounds like music come out? | Technology | explainlikeimfive | {
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"It's easier to grasp if you reverse the process and understand how sounds are recorded, because playing sounds through a speaker is just reversing the recording process (more or less). To record music (or any sound) in a studio, the performer sings/plays music and the sound is picked up by a microphone. A microphone is essentially a very sensitive membrane that moves back and forth when sound waves strike it. When the membrane moves back and forth, electronics/magnets pick up the movement and convert it into an electronic signal. The signal is what is saved in the recording. To play it, you just reverse the process - send the electronic signal (that contains the entire collection of sounds recorded) to a particular arrangement of electronics and magnets that are connected to another membrane (typically a cone shaped membrane in a speaker), and the signal tells the electronics/magnet how to vibrate the speaker cone/membrane. The vibration produces the sound wave that your ears pick up as music (or whatever sound is recorded). Note that your ears now serve as microphones, with the eardrum vibrating in response to the incoming sound waves, which are converted to an electrical signal by the very sensitive inner ear bones and their connection to the nerves that transmit an electronic signal to your brain. Your brain interprets these electronic signals as sound."
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j6pr3k | How do commercials work on live streaming services like YouTube TV? How do they stream their own commercials and how do they know the length and time to air them? | Technology | explainlikeimfive | {
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"From the streamer's point of view they just tell the streaming service that \"an ad break is starting now\". The streaming service or their ad middlemen then perform [automated auctions, allowing bots representing individual advertisers to bid to be shown to individual viewers]( URL_0 ) based on what the service knows about that viewer's demographics and interests. Streamers generally don't know exactly when viewers start seeing ads or when they've all returned from seeing ads, since different viewers get different ads. Some streams (typically larger corporate ones) have advertisements that are shown directly in the stream rather than customized for the viewer - these are planned and bought more like TV advertisements."
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j6q7xj | How come TV remotes are still so bad? | Technology | explainlikeimfive | {
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"Infrared signals from the LED bulb on the end of the remote sends a series of pulses of light to the piece of equipment being operated. This signal is basically coded instructions, so if the code isn't entirely received intact then the TV won't react. - URL_0",
"As u/MJMurcott said it's usually because they use IR. Some companies have started using Bluetooth instead of IR in their remotes and that cuts the delays massively (Virgin Media and Sky in the UK both use Bluetooth remotes for their Virgin V6/Sky Q boxes for example), but at the end of the day IR is cheap and remotes are almost always cheaply made.",
"My Samsung remote is the best remote I’ve ever used. Simple, great feedback, nice feel. Worst remote? Apple TV.",
"Is percussive maintenance another word for smacking it?",
"The simple answer is that they're reliable. As long as your remote can see the entire TV, it works, and the batteries last for years. To give you a more advanced answer, it really comes down to reliability. Infrared LEDs consume extremely little power. Cost is another thing. An infrared remote is basically a printed circuit board (cheap), rubber button mat (cheap), the LED and battery contacts (cheap) encased in a few pieces of injection molded plastic (also very cheap). Labor factors into this as well. The codes sent out by the remote haven't changed that much in years, decades even. Programming some extra codes is easy, and once you make the remote, you never need to update it. In fact the same remote will usually work across multiple different versions of TVs of the same brand. Additionally, it's dead simple. Put batteries in remote, point remote at TV, push buttons, it works. Which is important when you remember that part of your targeted consumer base is 80 or even 90+ years in age. To add though, several other remote options do exist. My comcast remote came with an optional radio receiver I could plug into the cable box. I enjoyed this feature in the past on cold winter days as I could use the remote from under a blanket. Additionally, my TV has an app that can interface with the TV. The only issue I have with it is that for some reason the app designer decided it needed a track pad instead of just four directional buttons & an okay button, so actually trying to navigate the on screen menus sucks horribly. The rest of the remote app works great. Anyhow, I could ramble on and on, but I think I'm done now.",
"I have a harmony remote that uses my home wifi and it is much more responsive than the TV remote. Works by putting a base station or optional IR repeater somewhere in the room with direct line of site to the TV. The remote sends signal over wifi to the base station, the base station pumps out the required IR signals over a much wider area. Also lets you use your phone as a remote. Hopefully TV manufacturers catch on and start making wifi enabled remotes and we can get rid of the IR nonsense completely.",
"Just adding: they’re getting much better. My Logitech works via wifi, so as long as I’m connected, I can actually operate things anywhere in the house. Pretty sure my Samsung remote is Bluetooth. Line of site isn’t really necessary anymore.",
"Am I the only one who's never had an issue with TV remotes?",
"It’s not the remote’s fault. It’s the woefully-underpowered microprocessor running the TV, probably on Embedded Java because the devs are too cheap to write to the hardware, and the accountants are too cheap to pay for a better micro. Margins are razor-thin on most entertainment center devices, so it’s not surprising that it turns out this way. A customer will buy the cheaper, slower set (especially because the customer doesn’t know it’ll take the TV 60 seconds to boot up and a second to respond to user input).",
"Also because us men beat the remotes hoping they will work faster thus making them not work well lol",
"IR is pretty dated. They’re also detached entirely from the interface and content they control. This is what makes Apple TV or an Amazon Fire Stick so much nicer, the entire experience is considered together.",
"It's just the new shitty smart TVs that are garbage. Slow responsiveness is due to a cheap processor. It seems like the more stupid apps you have connected on your TV the slower it works. That's why I don't give my TV internet connection at all. I either use my Fire TV box or PS4 for streaming. The TV itself cannot connect to the internet and it runs pretty smoothly this way.",
"It may be the distortion of memories from a long time ago but I think remotes have gotten worse as televisions became more digital. I remember the first television my family got that had a remote, probably mid nineties and it was just like flipping the dial on our cable box, instantaneous. I have a distinct memory of a new television and being frustrated because when I flipped through channels I had to wait through half a second of darkness between each channel.",
"The comments are mostly about design flaws but honestly you’ll get along really well with your remote control if you don’t use it while you’re eating and you keep the batteries fresh. I used to be a technician and pretty much every remote repair is taking it apart and cleaning it. They get absolutely filthy inside and the pads won’t make contact with the board. I hated working one those things- packed full of food grease and DNA.",
"The vast majority of infrared (IR) remote controls use a frequency of light in the infrared spectrum, but that spectrum covers a lot of territory. A remote for a TV that expects its signal in one part of the spectrum might not even be perceived by a piece of stereo equipment in a different part of the spectrum. This is why universal remotes use extremely wide-band IR LEDs that splatter their signal all over the IR spectrum. After the issues with IR wavelength are sorted, the remote pulse modulates the signal. It does not just turn the LED on and leave it on. Unfortunately, it can't just turn the LED on for a 1 and off for a 0. That would still be more problematic yet to reject light emitters in the view of the receiver that happen to be emitting those same wavelengths of IR light. Instead, when modulated, they're modulates at a stupidly high frequency, generally 38 kHz, well above the range of human hearing, should the circuitry suck so bad that it emitted sound as well. But this frequency is not hard and fast. Many electronic systems use approximations that can vary by a few kHz. And even then, the standard modulation frequency from manufacturer to manufacturer can vary from 20 kHz to 60 kHz. This can help for components to reject spurious signals in the environment as well as signals for other equipment that happens to be in the IR spectrum that it can see. Then, you can finally get to the incodings of 1s and 0s. Some times the 38 kHz( > ) pulsing means 1 and no pulsing signal means 0. Sometimes it's the other way around. Some times the meaning flips during the command signal due to the pressing of a single button. The rate at which the pulsing can start and stop can vary wildly as well. Even once decoded into individual bits, different manufacturers' coding standards can take a variable number of bits to identify which type of device is this command signal for? What is the command encoded in this signal? When you get right down to it, it's amazing you can have more than one IR device in the room at a time and have either one of them still function."
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j6uih5 | Considering how ubiquitous and cheap 64-bit processing is, and how long 64-bit technology has existed, why is 32-bit software and hardware still a thing? | For example, Arm is [dropping support]( URL_0 ) for 32-bit in future CPU's it makes. Why now and not earlier? | Technology | explainlikeimfive | {
"a_id": [
"g80ouj4",
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"text": [
"Because software from 10 years ago is still around today and can be run. It will be phased out eventually.",
"A lot of businesses like to buy something once, and use it for as long as humanly possible. Businesses will use computers, software, and any other machines until they just can't be fixed anymore. That means if you want businesses to buy your new stuff, sometimes you have to be compatable with their old stuff. Especially if a PC needs to interface with a manufacturing machine, which is twenty years old, and the software that runs it was made by a company that went out of business ten years ago, and the business needs their pc to run that ancient, un-supported software that operates the machine that lets the business stay open.",
"On the software side: simplicity for the developer. If your app doesn't require a lot of RAM, it might be easier just to create one set of code for 32bit processors and just use that for 64bit devices. Also keep in mind that there are still a LOT of new Android devices being shipped this year with either a 32bit processor or a 32bit OS on a 64bit processor."
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j6wta9 | What happens during server maintenance and why does it take several hours? | Technology | explainlikeimfive | {
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"text": [
"You know how your phone or computer does updates? Think that but times a hundred. Companies try to schedule all downtime into single blocks since uptime is important. This means they're patching their systems, releasing new features, and testing to make sure nothing breaks all in one go. Most systems are more than one OS so it takes time.",
"These days if a server is down for \"maintenance\" it usually means something has gone horribly wrong and the server has crashed (just like an app on your phone can crash). The server will then be \"down for maintenance\" until the problem is resolved, which can be anything from a few minutes to a few hours depending on what went wrong. Now days most businesses won't have any downtime for scheduled maintenance and updates (some slower/bigger organisations might be a bit behind the times though... like some government agencies). The new way of doing it is to run 2 versions of the server app at once, one being the old version and one being the new version, then once the new version is booted up and everything looks good, a switch is flicked to direct all the traffic to the new version instead of the old one. This transition is seamless to anyone accessing the site."
],
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j6y0xn | How do the "junk mail" filters for e-mail inboxes work, and what causes them to make mistakes? | I just checked my junk mail folder, and I received a Postmaster e-mail telling me that an important business e-mail I had sent came back as undeliverable. Yet it went to the junk mail filter instead of my Inbox for some reason. & #x200B; The other week, a client e-mailed me from the normal e-mail address they always contact me from...yet their e-mail went straight to the junk filter, even though 99% of the e-mails they sent me go to my Inbox, and the e-mail they sent me didn't appear (to me) to look different than any of the e-mails they normally send. & #x200B; Why does my junk mail filter make these sorts of occasional mistakes? Is there something that causes it, or something that can be avoided? | Technology | explainlikeimfive | {
"a_id": [
"g81bzzo",
"g81cmcf"
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"text": [
"The most simple spam filters are simply word-based. Those filters count the number of words that are usually in spam mails and compare that to the number of words that are usually in mails that ate not spam (aka ham). Of course, the reaction by spam mail makers is to use less spammy words and more hammy words. Another way to trick the spam filter is to use words it doesn't know (v1agra instead of viagra, for example) because they won't count in the end score. Newer spam filters look at words in context so they can guess what words mean even if they have never seen them. Also, they look at mail headers: information about who sent the mail from which server. That way, a filter can detect whether an email was sent automatically (like the undeliverable mail notification). Spam senders learn from these things too, and try to make their spam look so much like genuine mail that a spam filter gets more and more difficulty distinguishing ham from spam. Hence, more mistakes will be made.",
"Emails end up in the spam folder after a combination of many different \"scores\" and tests. Some examples: * Did the email originate from a server known to send spam? * Did the email contain something that vaguely resembles a phrase like \"make money fast\" or \"get a bigger penis\" or some other known spam wording. * Were dates wrong on in the email header (i.e. are the dates way in the past or in the future, indicating a spammers shitty configured mail server). * Did the email pass SPF? Was it originated by a server that is marked as being 100% associated with the sender's email address domain? * Were the email headers DKIM signed by the appropriate email servers as it transited. All of these little things add up to a score that says \"Yep, this might be spam\". & #x200B; > Why does my junk mail filter make these sorts of occasional mistakes? Is there something that causes it, or something that can be avoided? If someone can figure that out 100%, they will make a fortune."
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j70826 | What made PDF format so ubiquitous/popular? | Technology | explainlikeimfive | {
"a_id": [
"g81p4v7"
],
"text": [
"Because it is simple, small, and relatively safe. a PDF can be open and read by pretty much any document editor, while something like Word Doc or google doc might have formatting issues when converting. Hell you can pretty much open a pdf as if it is a picture. Because of the simplicity they also have small file sizes, which is nice for sharing things over the internet. and they're also pretty safe, while you shouldnt just go around clicking random documents from the internet that you dont know, from what I been told at company IT safety meetings (im not a web security person) it is hard to hide any kind of malware in a PDF file."
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j73ws5 | How do people snoop in on unsecured wifi networks? | I think I understand it if someone makes a network called "Free Public wifi", and then (through the router app??) they can read what you're sending to, and from the network. But can people pick up information sent to and from the network if they did not set up the network? | Technology | explainlikeimfive | {
"a_id": [
"g82e3oy",
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"text": [
"Sure. If you've got a network with no password or other form of authentication, then the connection to that access point is completely unencrypted and broadcast all over the local area for anybody to grab and read right out of the air. There are even tools for some of the older encryption protocols (WEP, most notably) that can grab enough information to be able to decrypt any of the information sent through the wi-fi. Think of it like eavesdropping on a conversation at the table next to you. The sound waves are there in the air for anybody to hear, you just need to tune into them and pay attention to what's being said.",
"First you need to connect to the network so you'll see the traffic on it. Then you can install a program like [wireshark]( URL_0 ) Then you need to put your wifi card into [promiscuous mode]( URL_1 ) this makes sure your computer will grab every packet instead of just the ones that are for your computer. Launch wireshark and start reviewing packets."
],
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j7a688 | If most TVs either have a 50Hz or a 100Hz Panel, shouldn't 100Hz TVs be able to Display 100FPS on say a PS5? If Not, why? | Technology | explainlikeimfive | {
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"text": [
"It could. But the Playstation also needs to be able to calculate 100 frames per second and thats usually where the bottleneck is.",
"a 100Hz TV would be able to show you 100 frames per second. That doesn't mean that everything will suddenly become 100fps, though. Some games are locked at 30 or 60. I've heard that some racing games will run at 120 fps.",
"The PS5 will feature a 120FPS refresh rate. You'll be able to see the 100FPS on a 100hz TV, or 120FPS on a 120/144hz screen."
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j7bm98 | How do usb hubs work? | How does so much bandwidth of multiple devices get carried through one? | Technology | explainlikeimfive | {
"a_id": [
"g83m0xg",
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],
"text": [
"It doesn't expand bandwidth at all. It's just a junction to allow multiple devices to share one port",
"The bandwidth gets shared between the devices. It gives each of them a different turn to speak. The turns don't have to be equal and they can change depending on which devices want to speak the most right now."
],
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j7bsfn | What's the difference between streaming and downloading | Technology | explainlikeimfive | {
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"text": [
"Downloading is putting water from the tap in a bucket to use later. Streaming is turning on the tap using it then turning it off.",
"Downloading saves the file to the disk. Streaming doesn't, except for temporarily in order to play the file. From a networking perspective they're the same."
],
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j7c1ms | Why does it take so long to delete software/reset devices? | My Samsung watch took like, 2min to restore itself to default for a new pairing and I was just wondering why that is. Shouldn't deleting stuff be super quick since you're getting rid of info? | Technology | explainlikeimfive | {
"a_id": [
"g83omtu"
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"text": [
"There's two types of deleting when it comes to most digital storages. The simple one is just \"marking\" the space where the file is as deleted, think of it like you having a book that is 500 pages long and you just writing on the first page that pages 350-400 are deleted. If you still wanted to, you could read those pages. The other type of deletion is actually wiping the bits off the storage device, so each bit on your storage device actually gets written over, think of that as actually ripping out pages 350-400 and then burning them."
],
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6
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j7gekv | How come when you insert a credit card chip, some make you remove the card rapidly and some make you leave it inserted? | Technology | explainlikeimfive | {
"a_id": [
"g84hw88",
"g84i3em",
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"text": [
"If you’re being asked to keep the card inserted, it’s chip based transaction. You can’t ‘swipe’ your card’s chip. So if you’re being asked to remove the card rapidly, it’s actually just getting you to “swipe” your card’s magnetic strip at the back of your card. They’re two very different types of machines - one being significantly older and dated.",
"Also worth noting that the EMV quick ship standards are being adopted. Instead of only referring to the card for all information related to the transaction, the reader copies some information from the card, stores it temporarily in the reader, allowing the card to be removed. This stored information is used to complete the remaining parts of the transaction.",
"When it reads the stripe, you have to move the card quickly so the read-head in the reader works properly. When it reads the chip, you leave it inserted so they can communicate with each other through the metal on your card. When you use rfid, you can just tap your card on the reader because it's using radio waves to communicate."
],
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j7hfhf | How do shipping/mail companies (USPS, FedEx, UPS...) figure out the logistics of shipping? | Is it just a computer program that figures out the quickest way to get the package to the destination? Is all of that information built in to the barcode and just gets scanned every time it hits a new place? It seems so complex with so many destinations, packages, and routes to take into account. | Technology | explainlikeimfive | {
"a_id": [
"g84n9c3"
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"text": [
"It is super complicated. The routing information isn't in the barcode itself; the barcode is just for tracking so that the various points along the journey can check in with the \"mothership\" and say \"Where's this supposed to go next?\". Large logistics companies are on the bleeding edge of operations research and optimization for exactly this reason...it's a hugely complicated problem with a ton of constraints and choices. The only companies with comparable optimization capability are airlines and large internal logistics organizations like the armed forces, and it's not a conincidence that they're all basically doing the same things (move object from A to B). Virtually no optimization engine will be running on \"quickest way\"...it'll be running to minimize cost while obeying the constraint of delivering by the deadline. If you paid for 2 day delivery and there's a 2 day path for $10 and a 1 day path for $15, it's going on the 2 day path because 1) that's more profit for the company and 2) they want to preserve capacity on the 1 day path for customers who actually want/pay for 1 day shipping. Similarly, if the 1 day path is $10 and the 2 day is $15 (because of other transports that are already running) then they'll send it 1 day even though you paid for 2...that's why you sometimes get stuff early."
],
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j7iw9r | How do digital game sales work? We get a discount, but who ends up getting less money; the distribution platform (Steam, GOG, etc) or the actual game companies? | Technology | explainlikeimfive | {
"a_id": [
"g84wtt3",
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"text": [
"The distribution platform (like steam) takes a portion of each item sold, regardless of the final price if it’s on sale or full price, Steam gets their part. The remainder goes to the game company. For Steam it’s generally 70/30 split. 70% to the game, 30% to Steam. A 70/30 split is considered standard in digital distribution for games, movies, music, etc. So if a game sells for $50, Steam get 30% ($15) If the game sells for $10, Steam gets 30% ($3)",
"In a game sold in a store, a little under 50% goes to the game studio, about 30% goes to the retailer (which will be responsible for shipping, handling, storage, shelving, loss from unsold games, and such related costs), and about 20% goes to the platform, which covers cost of production of the physical game copies. A game sold in an eShop will have a much cleaner breakdown. The studio typically gets 70%, and the platform gets 30%. The platform has to cover the cost of running the eShop, and that's it. So the platform gets a larger chunk, and their operating costs scale much better. There's no accounting for unsold games, and there's no store that needs to pay rent. Basically, the studio and the platform have taken the game stores share and split it between themselves."
],
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j7lxct | How does CGI work? Do you have to draw whatever it is frame by frame? | Technology | explainlikeimfive | {
"a_id": [
"g85k717"
],
"text": [
"\"CGI\" is an incredibly broad term. It is imagery produced by computers, which can be anything from cartoon animation, 3D stills and animations, digital effects in conventional movies, and a bunch of stuff I can't think of right now. All that said typically a major benefit of using computers is that you don't have to manually draw every frame. A cartoon animation for example might be able to take a line an animator placed in two different locations and extrapolate where it should be in intervening frames. Or a 3D animation uses the models/textures/paths produced by the animation team and the computer renders how it actually looks. \"CGI\" certainly isn't just a bunch of guys painstakingly painting every pixel on their own."
],
"score": [
6
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j7mp4d | How a fingertip pulse oximeter works? | I know how it measures the pulse that's pretty simple to figure out but how can it measure my O2 sat? Can it tell by my heart rate or is there more to it? | Technology | explainlikeimfive | {
"a_id": [
"g85w47u",
"g85p5db",
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"text": [
"Hemoglobin (the Oxygen-carrying component of blood) saturated with Oxygen lets a lot of red light pass through, and just a little infrared light to pass through. Oxygen depleted hemoglobin lets more infrared light to pass than red light. This difference is important, because if it was just a matter of being more transparent to one kind of light, then the measurements would be affected by darker/thicker skin and/or nails. The oxymeter has both a red light an an infrared light, and it compares how \"transparent\" to each your finger is. Doing this, and also taking into account the variation of measurements due to the pulsation of the blood, it can tell apart what is blood and what is flesh/skin/nail in terms of obscuring the red/infrared lights. Then it compares with what it knows about the absorption of each light by blood with different O2 levels, and gets to the O2 saturation value. Here's a very good video that explains it in simple terms: URL_0",
"Oxygenated blood is a brighter red than deoxygenated blood, so when your oximeter passes a light through your finger tip, it can measure how much light gets through, which changes based on how oxygenated the blood is.",
"Magic. Actually it measures the intensity of the light that penetrates your finger, the intensity is affected by oxygenated blood so it can give a pretty accurate indication of your blood oxygen levels to a pretty good degree of accuracy. Technology Connections did an excellent video on them if you need to know more."
],
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"https://youtu.be/4pZZ5AEEmek"
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j7n1is | Why were estimated operation times when moving files so inaccurate for computer systems | For example, if lots of files had to be transferred or downloaded from one pc to the other, it could say it would take minutes when it would take hours or visa versa. How was the computer "deciding" that it would only take a short amount of time when in reality it took a long time | Technology | explainlikeimfive | {
"a_id": [
"g85sf82",
"g85rjpz"
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"text": [
"How long would it take you to buy 50 items from Walmart and put them in your car? You could guess and say 60 minutes, but it depends a lot on what those items are. If we're talking about 50 AA batteries, it'll take you like 5 minutes. If we're talking about 50 jugs of milk, you'll probably need to make several trips and it'll take a lot longer. If we're talking about 50 random items that you need to search for throughout the whole store, you could be in there for three hours or more. It's pretty similar with computer files. A large file takes much longer to copy then a small one, and if the computer needs to copy lots of small files from a hard drive, it may have to look for them first and move the physical read head from one area of the drive to another one, which takes time. The computer can give you a rough estimate, but it won't know how long it will actually take to search for and transfer a file until it actually does it.",
"It depends on how it's performing the calculation. If it took 5 minutes to move 5 out of 10 files, it could say 50% done and 5 minutes remaining. And even if the other 5 files were 20x the size, the 50% progress bar would be correct, but the estimated time would definitely be wrong. It was basing it on what it had already seen. Especially if it used FTP (File Transfer Protocol) which generally doesn't know or report how long things take. Modern operating systems with fully indexed hard drives will be more accurate, but even then it doesn't know what the other computer is doing, so it can only guess."
],
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j7oqzt | How a railgun functions and also Lenz’s law and Fareday’s law have to do with it? | Technology | explainlikeimfive | {
"a_id": [
"g861pj5"
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"text": [
"Because Science did a video on this and explains better than me ( URL_0 ). However, here is a basic run down. It uses the Lorenz force for all of it. Effectively running a current through a wire will cause of a force experiences perpendicular to that wire. The force is directly increased and decreased with the amount of current run though the wire. So, the idea is run a massive amount of current through a large wire. The proportional force will be immense. However, it is not very focused. Railguns focus this power by creating long tubes in order to focus the force down the barrel."
],
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