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77ctfu | Why is there a pause during TV news when crossing between the studio and a live correspondent? | Technology | explainlikeimfive | {
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"There's usually a few moment delay from what the anchor says and the reporter hearing it due to the sat truck, microwave truck, or cell signal sending and receiving data. Source: anchor/reporter"
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77dud1 | If the edge of a rotating disc moves faster than the center, is this accounted for when pressing a vinyl album? | Wouldn't the music have to be slowly sped up over time? Otherwise I feel like the music would sound slower and slower as the needle gets closer to the center. | Technology | explainlikeimfive | {
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"Yes. And this is pretty easy to cater for, because vinyl discs are created from being pressed in a mould, which is itself created by manually inscribing the tracks onto a spinning disc, rotating at the same speed as the eventual pressing.",
"In a vinyl album, the inner tracks are indeed more compressed than the outer tracks. But since this affects both the recording machine and the playback machine in exactly the same way, the music speed is unaffected. CDs and DVDs actually change speed to adjust for this, so they can fit more music per rotation on the outer tracks.",
"When designing a disc format, you have two choices: Constant *Angular* Velocity (CAV) or Constant *Linear* Velocity (CLV). Vinyl records are a CAV format - this means that the disc always makes the same numbers of RPMs, which is a much simple playback mechanism. The tradeoff is that the quality of the inner & outer tracks will differ slightly. Other formats, like DVD & Blu Ray are CLV - they change rotational speed so the same amount of \"stuff\" gets read over a period of time. This requires more complex hardware for spinning the disc but it makes the data encoding much simpler. In either case, the difference doesn't really matter because the recording is made with the same technique as the playback."
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77e8tq | How do animated movies stay up to date when they take multiple years to complete? | I would imagine that, with technology constantly improving, an animated movie that started production five years ago, for example, would end with an outdated product. Are animated movies just a reflection of the technology we had when they started animating it? Or do they somehow update their equipment and programs so this isn’t a problem? | Technology | explainlikeimfive | {
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"All the other movies are \"outdated\" too, so everyone ends up on a level playing field. Just like with videogames. And yes, this means that if your schedule takes longer than usual, you'll be behind the curve. This is what stalled Duke Nukem Forever. I think the effect is somewhat lessened in movies where there's a greater focus on story rather than technical animation.",
"One important thing to note is the production cycle of films isn't linear. They don't finish 1% of the film one day, then move to the next percent. They write the whole story, make tons of sketches and storyboards, record dialogue, make animatics for certain sequences, etc, before moving on to previs CG, then better rigging, more texture work, etc. They eventually get roughly set sequences, then continuously polish the film and animation often for a long, long time. So a 3 or 4 year production cycle, but the last animation renders are only a month old when it is finished, and the last updates may include newer tech. So parts of the film may be technically dated, but other aspects may be cutting edge. Since EVERYONE does that anyway, everyone is an equal bit behind, so it doesn't matter much anyway.",
"To be honest, there's not that much difference in the quality of a cutting edge 2007 Pixar movie and a 2017 average animated kids film. If you start your movie in 2017 and don't finish until 2020, it's not like it will look out of date. The only example I can think of would be Foodfight! which started in 1996 I think and wasn't finshed until 2012. It looks terrible.",
"For me it is easier to answer this referring to video games than animated movies. But both the animated movies and a lot of games are innovating behind the scenes, trying to create the next generation of technology so what will be 'standard' in like 2020 is being worked on right now. When things get pushed back and take WAY too long, that is when they really show their age upon release. Like \"We started in 2010, creating the technology for 2012... but got released in 2017 due to issues so we look 5 years old\".",
"> Are animated movies just a reflection of the technology we had when they started animating it? To an extent, yes, but that is true for anything using an emerging technology. By the time Apple finishes their latest iGadget, there is some new technology out there they weren't able to use. This is is true for everyone making something big, so it really isn't outdated if you aren't falling behind. Also, these days animation technology is fairly stable, what is changing are better techniques, project management, and rendering hardware. The first two are just a matter of talent, experience, and organization, and the last one can be updated to the latest technology when it is needed towards the end of production. Finally, it doesn't really matter that much with animated movies. *Toy Story* is over 20 years old, and holds up reasonably well. The differences between 2017 technology and 2012 technology are subtle enough that no one is going to walk out of the movie because the animation sucked."
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77g19k | Why are the twists in Cat V strands so important? Why can't they just be straight wires? | Technology | explainlikeimfive | {
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"The twists reduce the \"magnetic flux\" caused by magnetic fields in the environment, reducing interference. Nearby electrical circuits will cause fluctuating magnetic fields in the region of the cable. These fields will create an \"induced voltage\" in the cable circuit: the induced voltage depends on the magnetic flux, which is the number of field lines which poke through the gap between the two strands. This induced voltage will interfere with the signal. So clearly you want the two strands close together to minimize the gap, but because of their physical size and insulation, you can only get them so close together. But if the wires cross over each other, the magnetic field pokes through in one direction for the first half-twist, then pokes through \"backwards\" for the other half-twist, and so on: each half-twist cancels out the previous one, so the total magnetic flux is much closer to zero. URL_0",
"Twisted strand uses the transmission of electricity to cancel out the noise in the cable. Without the twist the cable is more sensitive to interference and generally can cause transmission issues with reduced speed due to errors.",
"When an ethernet cable (or any wire) runs next to a run of power cables, the power cables will induce current into the ethernet cable. This is similar to the way that an inductive, or wireless, charger works for your phone. If your ethernet cable is not twisted, there's going to be one that is closer to the power cable, therefore getting more induced current. If they are twisted, the power cable will induce current more current to one wire, then the other, then back to the first... eventually averaging out so both wires in the twisted pair have the same amount of inducted current. The signal on the wire is the difference between the voltages on the 2 wires, rather than an absolute voltage. There are good reasons for this, relating to ground state differences, but that's for another time. The important thing is the devices are looking for the difference in voltage between the 2 wires. All this comes together to mean that the twists cause any added current to be added equally to both sides, thereby not corrupting the signal.",
"Alright so I'm going to make an attempt at an *actual* ELI5: Let's say you have two long roads right next to each other (a single pair). And there's no way for cars to go from one side, to the other side. These cars spell a word from front to back, so they need to stay in the order they're in. It's also crab mating season, so all the little crabs want to come onto land to breed. This means they have to cross the roads (outside interference). If we keep the roads as is, the crabs will flood the road, and cars will have to stop, they might crash, they might get passed by cars on the other side which will get to the end before them, messing everything up. BUT, if we add \"S\" turns into each road for the whole length(the twists in the pair), so they overlap creating many intersections, something cool happens: When crabs flood one side of the road, the cars can just split off to the other side. BUT THEN BOOM, MORE CRABS ON THAT SIDE! But it's cool, there's another intersection and we can just veer back to the other side and go around these crabs too! We don't want no crabs affecting our perfect line of cars. Twists keep the crabs from affecting what's happening on the roads.",
"Because moving ambient electromagnetic fields induce electrical current in wires. Current that's not your signal. Twisted pair makes two wires with opposite directions, making outside interference mostly cancel itself out",
"True ELI5: because it works better. Want some fruit chews or applesauce?",
"It takes 2 wires to transmit one signal in this setup. It is called a twisted differential pair. The 2 wires send exact opposite signals of each other, so that the electrical interference from the 2 wires cancels out. This prevents the pair from sending interference out. The cancellation works best when the wires are very close to each other. The twist keeps the wires tightly together. Also, the electronics look at the difference in signal on the two wires to decipher a signal. If there is outside interference acting on the wires, it will act equally on both wires because they are so close to each other, and they both will go up and down in voltage together. The difference in voltage between the two wires will stay the same even with outside interference acting on the wire pair.",
"My recollection of this is a little fuzzy but I feel like some of the existing comments are forgetting that in a proper twisted pair the signal is [differential]( URL_0 ). What that means is say you send a signal, you'd send it normally on one half of the pair and the inversion on the other. At the end a receiver then mixes them back together. If any noise happened on the line it would happen on both lines, and mixing process on the receiving end can now identify what is signal and what is noise, and remove the noise. If we think about the signals as numbers, say we sent the number 16. On the wire we send 16 as it is, no change. On the second half we send -16 (the inverse). Now say half way through transmission there is a big noise spike (we'll say it was a +3) from a nearby outlet, and it adds itself onto our twisted pair. Well at the end of the line the receiver gets a 19(16+3) and a -13 (-16+3). The receiver's mixer sees that they are different, and when it puts them back together can calculate the offset and bring us back to our original value. If you didn't have a differential signal pair, the noise would just affect our original signal (16 - > 19) and the receiver would have no way of knowing if 19 was the original signal or not. To answer your original question, the twist comes in to play in CAT5's case to help keep wires from running parallel to each other. Wires running parallel to each other over long distances allow for great inductive cross talk. CAT5 cable actually specifies different twist rates for each pair so that they without a doubt are not lying parallel with each other over the run of the cable."
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77if5x | How do artists create the “localized” versions of their songs in which they mention the local radio station by name? | Technology | explainlikeimfive | {
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"> Does the artist have to sit in the studio and sing different station names or identifiers so that they can later be edited in? It is relatively easy for a label to have their artist go to a studio and sing a bunch of radio station names all in one big session."
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77irss | How can some live TV shows censor profanity words before they are even said? | Technology | explainlikeimfive | {
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"there is a lag before it is actually broadcast The lag is due to operational delay as well as intentional delay i.e, Broadcast delay. Commonly, the intentional delay is about 7 seconds that is the broadcast will automatically only be sent out after 7 s from when it is recorded this gives time to edit profanity."
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77jrml | How does the Pirate Bay still exist with the same URL even though it's been shut down multiple times? | Technology | explainlikeimfive | {
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"A domain name is like a nickname. It translates to an IP address that actually identifies the web server you need to talk to. (You said \"URL,\" strictly speaking that includes stuff like the specific file on the server you want and the protocol you're using, in addition to the domain or IP address.) What domain name belongs to which IP addresses is advertised by a domain name server. And which domain name servers are authorized as the official servers for that domain is indicated by a registrar. This means that, to \"seize\" a domain name and direct it somewhere else, it's the registrar you need to control. The registrar for ` URL_1 ` is currently EasyDNS, a Canadian company. Its policy is not to take down domains unless it receives a valid court order. So far, no Canadian court has issued such an order. Other registrars have much less protective policies and may take down domains simply because a third party, like a copyright holder, asks them to. Obviously The Pirate Bay won't be paying for their services. Pursuing a court order is often not a profitable strategy for copyright holders because it takes a long time and is expensive, what The Pirate Bay does isn't necessarily illegal (depending on jurisdiction), and other registrars in other jurisdictions are probably willing to serve The Pirate Bay instead. At one time its ` URL_0 ` domain was seized, but the website was served through lots of mirrors on other domains instead, and eventually got back to ` URL_1 `. Fundamentally, trying to take control of domain names is not an effective way to combat copyright infringement via torrenting."
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77lltk | Internet Links | Why is it that if I click a link to go from one website to another, I see multiple different websites changing in the address bar, even though i'm only going to one website and my screen isn't changing multiple times? This doesn't happen all the time. I also wonder why it isn't consistent. | Technology | explainlikeimfive | {
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"HTTP requests - which are what happen when you click a link - can have a number of responses. It might be a response that’s the web page you want, or it might be one that says “no that doesn’t exist” (the dreaded 404). Or it might be a *redirect*. This tells your browser to visit a different page instead. That’s what you’re seeing happen."
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77ln0u | How do loading bars know how far they are, and why do they rarely give a very accurate time on when it will be completed? | Technology | explainlikeimfive | {
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"Progressbars show how much data to move and how much remains; To calculate the time it will take to finish it uses the speed of which you move a certain amount of data and divides that by how much data theres left. If the rate you move data changes the time to finish will also change.",
"**ELI5** if you have 10 things on your todo list, and you did 5. You are half way done! except if those 5 only took you 2 min to complete, and the next 5 take an hour to complete, it'll be inaccurate. its hard to tell how long a task will take until its done.",
"Not all loading bars are about downloads. In many scenarios, they are displaying a percentage of total task count completion, regardless of the size of the task or rate of task completion. For downloads, your download rate changes often, plus what the other users mentioned as well.",
"Predicting the time disk operations will take is nigh impossible. Let's say you have an installer that's started by writing game_textures.dat, which is a 1GB file. The first 50MB got copied in 1 second, thus it's going at 50MB/s, thus the entire file will take 20 seconds. Easy. But right after that, it starts copying the 5MB long game.exe, which will take what, 1/10th of a second? Turns out that no, because that's an executable. The antivirus kicks in and spends 5 seconds on the file. Now your prediction is completely out of whack. How does the installer know there's an antivirus and how long it will take to go through the file? It really can't. And at any random time, Windows can decide it's time to download updates, or to index the disk, or do anything else which will take resources away from the installer. So really, progress bars are more useful as an indication \"something is being really done, and it will eventually end\", than as precise indicators of when something will finish. For them to work well the task has to be highly predictable. CPU bound operations where each part takes as long to process as any other, and a few niche operations like writing DVDs are very predictable, but some other things are not."
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77lzch | How do radio stations know how many listeners are tuning in? | Technology | explainlikeimfive | {
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"In 2006 my household was chosen to be a Nielsen radio family (Nielsen does radio as well as TV ratings) and we kept a daily log of which stations we listened to and when.",
"There are two popular methods these days; the most common is listening diaries (usually a company will send out a survey with a few dollars as incentive to fill it out) that are sent out during ratings periods. There's also what's known as \"PPM\", or \"Portable People Meter\", which is far more accurate in determining what someone is listening to. You can read up about it on Wikipedia: URL_0"
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77m4w8 | How does SHA-1 work? | Is there anyone who could possibly explain to me how does SHA-1 hashing algorithm work ? Explain like im 5 pls. | Technology | explainlikeimfive | {
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"SHA-1 is a block cypher, meaning that it breaks up a message into chunks that are 160 bits long, and scrambles them up according to a complicated formula. Then it repeats this process block-by-block on the rest of the message. And it repeats it again over the already-hashed blocks, scrambling them a second time. And then a third time, etc etc. The scrambling formula is given by [this]( URL_0 ) diagram."
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77nk5i | Why aren't private airplanes common? | Technology | explainlikeimfive | {
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"There's more to it than simply the cost of the plane itself. Obtaining a license to fly is incredibly expensive if you didn't get it through the armed forces. You have to rent space to store them at an airport. And you have to pay for maintenance and fuel which can be expensive."
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77nt77 | Can anyone simplify parity and/or error checking in data storage context? I simply can't grasp how a parity stripe in RAID 5, for example, can rebuild missing data, but isn't actually a copy of the data. | Technology | explainlikeimfive | {
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"2 + 5 = 7 Stripe 1 contains: 2 Stripe 2 contains: 5 Stripe 3 contains: 7 (or, the **parity** stripe) \"Oh no!! Stripe 2 went missing!!\" 2 + X = 7 Solve for X 7 - 2 = **5** Ta-da, parity Now, the striping is distributed across all drives in the RAID array, which is nice, because any drive can go down. There is no dedicated parity drive like with old RAID levels. This also distributes wear evenly across the drives. You do lose space to the parity stripe. Edit for more thoughts: So, obviously, the parity stripe and all the data stripes it pertains to will never be on the same drive. The RAID controller issues stripes round robin to all the drives, so, it literally can't happen. So, when a drive goes down (and is replaced), the RAID controller queries all the parity and data stripes on all the other drives and starts rebuilding the data on the empty drive. This is why IO performance is hampered during a drive rebuild.",
"Let's say I have three binary messages: Message 1: 1010101010101 Message 2: 0000011111111 Message 3: 1110000011111 I will define a parity stripe as the bitwise xor value of all three of these messages. Parity = 0100110110101 Now let's say message 3 is lost through a hard drive crash. 1010101010101 bitwise xor 0000011111111 bitwise xor ????????????? = 0100110110101 It is easy to figure out the missing message."
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77qr8y | Why do images of computer screens show weird patterns when you zoom them in and out? | Example: URL_0 | Technology | explainlikeimfive | {
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"Those are pixels. Though you may also be referring to the moire pattern which appears when photographing a television or monitor from further away. Essentially they happen because the pattern of pixels on a monitor and the pattern of pixels of a camera don't match up quite right and end up making weird patterns. See: [Moire pattern]( URL_0 )",
"In a nutshell it's like trying to display a fraction when the numbers you are allowed to use are whole numbers only. How would you represent 1/2 if you can only choose 0 or 1? Some you might say are 0, and others you might say are 1. So you're losing information when you store the fractions using whole numbers. This is kind of how digital displays and digital cameras work to render pixels on a screen, or photograph them. Most displays are pixel based and there is a very tiny sequence of red, green, and blue squares which light up to form a single pixel (subpixels) and they are fixed in place. There are also pixels in the CCD or CMOS sensor of a camera, which are also fixed in place. Now in a perfect scenario, the camera distance and zoom would be such that for every pixel on the display, a pixel of the camera picks it up. This would be a 1:1 pixel ratio. But what happens if the camera has more pixels or smaller pixels, or the distance to the display is not perfect for 1:1 viewing? The pixels may not align between screen and camera and so some camera pixels will see two half pixels, possibly of different colors, and so it will show something halfway between those two pixels in color and brightness. Meanwhile other sensor pixels may pick up a single clean display pixel and show it accurately. This difference between perfectly captured pixels and partially captured pixels is what causes the noise and screen door effect as the camera moves closer or farther away. Since the pixels are arranged in rows and columns at fixed distances from each other, we see this as aliasing or bands of dark areas or noise. The reason you don't see this effect very much using film cameras is because they use little particles of light sensitive emulsion that are scattered randomly all over the film. They aren't lined up in perfect rows and columns like a digital sensor would be. So when they record the light from pixels that aren't at a perfect 1:1 ratio, the distortion gets spread evenly throughout the random placement of the film, instead of lined up in perfect rows and amplifying this pixel distortion. You can also have this problem with LCD and other pixel based monitors that have fixed pixel widths and arrangements. Say that your monitors native resolution is 1000x1000 (for ease of understanding just go with it). You play a game that has a resolution of 940x720. In order to get a 1:1 ratio, the monitor would need to display the game with black bars around the edges so that the total resolution was still 1000x1000. If you wanted to play it in full screen, it could stretch the image, but then the pixels wouldn't line up anymore. The result would be jagged aliasing lines similar to using a digital camera. Squares wouldn't be perfectly square, straight lines would look jagged and not clean. But lets say that you play the game at 500x500 resolution at full screen. The monitor can simply double the pixels and use 2 of it's pixels to render 1 of the games. The result is 500 goes into 1000 twice, and so with a 2:1 ratio, it would still be possible to have sharply defined lines and the pixels would match up evenly and the screen would look good. The same if the game rendered at 2000x2000 but the display only went to 1000x1000. The display would simply use 1 pixel to render 2 of the games pixels and it would still look clear and noise free. The smaller the pixel size on the display though, the less this becomes a problem as you would have to get closer and closer to the screen in order to notice. On a 4k monitor, you basically can't see it anymore. This is why it's always best to run a game in the native resolution of your monitor, and if that's not possible, then running it in an even ratio is the next best thing."
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77ulwb | What is "bridge mode" on a router, and when it is useful? | Technology | explainlikeimfive | {
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"It can mean different things. A home router is often a router and a modem combined, but the router part tends to be pretty crappy. Bridge mode basically disables the router part, allowing you to use the modem to connect a second device directly to the Internet. The downside is that you can only connect one device this way (usually). Hence, it is usually used to connect a second, better router. The upside is that the slow and buggy built-in router goes out of the way. Then there's also bridge in the context of WiFi, which was already explained.",
"In computer networking with the tcp/ip protocol (the one the internet uses), you have small networks linked together by routers to become a large internetwork. A single network is identified by its use of a single tcp/ip addressing “subnet”. In tcp/ip, every computer on the network has an IP address, and you can use that address to figure out which of all the connected networks that computer is on. Imagine that a subnet is like the block your home is on, and if you saw the home address of another house you’d be able to tell just by looking at the address if that house is on your block or another block. So routers are the things that connect subnets together, that take network “traffic” and forward it to the next subnet if it’s supposed to go that way. But if you change the router to “bridge” mode, that tells the router to treat both sides, both networks, as if they’re the same subnet. Effectively it makes a transparent connection between the two networks so they become one. The ip addresses on both sides have to be in the same subnet. The “bridge mode” router now forwards ALL traffic it sees on one side to the other side automatically.",
"So before this question can be answered I feel like an explanation of what a router does and what a bridge does in the context of networking is useful In networking routers and bridges were kind of designed to do the same thing. Take two separate networks and connect them together. The major difference is how that is done. With a bridge the two networks are connected together to make 1 larger network. With a router, the two networks remain unchanged, but they still gain the ability to communicate with each other. In terms of a home router, or router that is supplied by the ISP. Think about the internet as one network, and your computers and devices as another. In bridge mode, your devices are connected directly to the internet. In routed mode your devices are connected to their own network, but gain the ability to communicate with the internet. This is much more secure way to connect your devices to the internet. Like any other product, routers can vary in performance, and features, so bridged mode is useful when the modem/router combo your ISP supplies you does not meet your needs and you'd like to add your own. So you place the modem/router into bridge mode, and then connect your own router. Then it's like your router has been directly connected to the internet.",
"In bridge mode the bridge router uses it's wireless to connect to the wireless of another router. This forms a wireless link, or bridge, between the two. The network ports on the bridge router are used to connect non wireless clients to your network. Those clients can communicate with the rest of your network due to their traffic being sent over the wireless bridge. This is useful when you have a spare access point and want to use it with non wireless computers. I have an upstairs desktop that uses a bridge router for it's connection which saved me from having to buy another wireless NIC. Another benefit is if you have multiple wired computers going to the bridge router. They all share the one wireless connection which slows them down a bit but doesn't slow the whole wireless network down as much as multiple wireless clients each with their own wireless connection would. Also because wireless access points tend to have larger antennas. They can typically communicate over longer distances. Say like between a house and detached garage.",
"Bridge mode is simply a way to turn a wifi signal into a hard wired port on your network. Let's say you wanted to connect your smart TV to the internet, but there is no wifi functionality and there's only an Ethernet port. But the TV is on the opposite side of the house as the router, an on a different floor as well. You could run a cable several hundred feet, through walls and through the ceiling and connect it that way. Or you could take a 2nd router and create a wifi bridge. The 2nd router acts more like a wifi receiver, connecting to the existing network as a new wireless device rather than creating a new wifi network. The ports on the router then act as a local switch, and in some cases multiple devices can be connected. So now the internet signal travels from the modem to the wifi router, then to the bridge, along the cable and into the television. And vise versa. Bridge mode let's you create a wireless connection between wired devices. A bridge.",
"A switch is a multiport bridge. There are occasions where you don't want a router to route. You just want it to act as a switch. For example, my 2nd router is used as a 2nd wireless access point and switch. Thus, it is acting as a bridge. It doesn't route.",
"A router connects two networks together. Data that needs to be routed needs to go through a router to determine where it needs to go. You need a router when traversing differing networks (eg. your home network, to your ISP, to the internet, to Reddit's ISP, to /r/IASIP). You don't need a router when you're in your own network (technically, broadcast domain). Going from your computer connected to a switch, to another computer in that same switch does not require routing. If everything is connected to a single switch, that's one broadcast domain. If the two switches are connected to each other, that's also a single broadcast domain (excluding enterprise networking, where a single switch can do magical things, like VLANs, L3 routing within, client isolation, and more). Bridge mode makes a router act like a switch, where it stops trying to route packets across the network. Then, you can use a router in bridge mode to connect to another switch, and have it all be on the same broadcast domain. You'd use bridge mode at home in examples such as: * Reusing an old router to extend your current network, but don't want to do weird things like double NATs inside your home network. * Bypassing your required ISP router (Looking at you, VZ FiOS) so that you can use your own router without doing the above double NATs. Sight tangent: using double NAT can cause connectivity issues with services such as online multiplayer, and introduces an additional step required to disable the inherent-by-design one-way flow of data when using typical home/SOHO routers using 1:N NAT.",
"There is a \"bridge mode\" in all-in-one modem/router/wifi combo boxes that disables the router and wifi so you could use your own/better equipment if desired. If bridge mode is disabled and you put in your own router down stream (most times) you're going to have internet issues. I can get more detailed and non-eli5 if wanted.",
"A practical example I've used: I had my phone, laptop, and another device with only wired ethernet. My phone has 3G internet and can hotspot my laptop over wifi. My laptop has wifi and an ethernet port. I bridged my laptops wifi+ethernet port while on my phone's hotspot. Plug in wired device to laptop, got dhcp+internet from the phone's wifi hotspot.",
"My work phone requires a hardline internet connection (can't connect wirelessly) - bridge mode allows the bridge to connect to my wireless router (in another area of the house) so I can connect my phone to it through the bridge. It is not acting as a wireless router anymore - It does not duplicate or repeat a wireless signal to act as a separate wireless router",
"Practical use: I’m a network engineer and use a hardware firewall on the edge of my network. For work purposes, I want the “public IP” address normally assigned to my modem on my firewall instead, so I put the modem in bridge mode. It basically disables routing functionality on the modem and just passes the public IP back to the firewall instead and ONLY acts as a modem.",
"I'm a bit late but I feel like true ELI5 is still missing, so let me give it a go. Your typical home router is actually multiple devices in one - modem, firewall and router. Let's imagine, that your download is like apples delivery to apple processing factory. First there's modem, that's a worker that can unload all the apples from truck and puts them on the belt. Then there's firewall, that's a guy down the belt path, that's filtering all the bad apples out. Finally there's router, this guy takes all the apples from the belt and puts them on one of the outgoing belts. Some apples are good for cooking, so they'll go to the cooking belt, some are nice enough to be packaged and sold. The beautiful ones will end up on premium belt and will be sold in those fancy packs as a premium produce. The router decides the future destination of each apple. Now in regular mode, your router does all those things above. In bridge mode, only the modem part (unloading the apples from the truck) is done. Why would you want that? Typically it's because you'll connect better (dedicated) firewall and router down the road. (imagine it like a separate unloading facility with separate building for the other stuff) Your computer can work as router and firewall as well if you connect it directly in the bridge mode. Sometimes it makes the installation easier if you want to connect just that one computer.."
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77vlvc | Why when you microwave food on a plate, the food heats up but the plate stays cold? | When I put a plate of food in the microwave, the food and any parts of the plate that are in contact with the food get very hot, but any parts of the plate without food (like the edges) seem to stay very cool even immediately after taking the plate out the microwave. Why is this? | Technology | explainlikeimfive | {
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"Microwave ovens work by vibrating the bonds in molecules present in food, particularly water. The molecules with these kinds of bonds are typically not present in most crockery meaning plates that you put in the microwave don't heat by any mechanism other than conduction from the food itself.",
"The microwave makes water particles \"dance\" and when they \"dance\" they heat up. Your plate does not contain water so no party over there. Get it?"
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77vmiv | How is research carried out in order to constantly develop and improve CPUs and GPUs? | What does improving these computer components involve and what methods are used to develop more efficient processing units? Edit: with a strong emphasis on the experimental aspect | Technology | explainlikeimfive | {
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"There are three main ways to improve a CPU. First, you can make it faster, able to execute more instructions every second. The problem is the faster you go, the hotter and sloppier the chip gets, to the point it eventually fails. Next, you can make the components smaller. The smaller the chip architecture, the more transistors you can fit into one place, and the less power the chip needs, reducing heat. Finally, you can make the chip smarter. Find ways to do things in 4 steps instead of 5, do multiple things at once, improve caching, and in general do things more efficiently. Edit: Clarified the language on the second point.",
"It's really complex, but the very simplified basics are: 1) Figuring out how to make smaller circuits on the same size chip, i.e. cram in more circuits to the same space. (this is what was/is behind the famous Moore's Law) - this can require creating an entirely new process of etching out the circuits on the silicon wafer. 2) Figure out how to make the same number of circuits perform more calculations in the same amount of time (i.e. better circuits, not just more of them) - this is what is referred to as \"instructions per clock\" or IPC 3) Figure out how to make the circuits run faster (i.e. more GHz) without problems like overheating or random errors",
"As others have pointed out, Moore's Law/Dennard Scaling have historically made part of the progress easy. You get more/faster transistors at every generation. (That's pretty much at an end now, though.) The trick is then to figure out how best to use those benefits. With CPUs, one of the things you can almost always depend on is making the internal cache memories larger. The performance hit from going off-chip is so huge that you almost can't have too much cache memory. After that, it gets complicated. One of the things that you could look at historically for CPU improvement was to look at what was going on in previous generations of mainframe and supercomputers. Microprocessors eventually put inside of a single chip the things that those systems were doing to improve performance. Another mainstay was to simply absorb functions being done by other PC motherboard components. You didn't necessarily improve the CPU performance, but you improved the performance and cost of the motherboard as a whole, which is really the point. No matter what changes you were going to make to the CPU, one thing was constant: simulation. No matter what changes you thought might bear fruit, the key was to build a model of your new CPU and simulate the performance under a variety of workloads. Designing and manufacturing a new microprocessor is incredibly difficult, time-consuming, and expensive. You want to be reasonably sure of what you're going to end up with at the end of the day. Back in the day, we even used to build hardware emulators, since you could get much more done with them than software simulations. But that's not really done too much these days with super-complex chips like full microprocessors."
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77wbj9 | What are programming design patterns? | Technology | explainlikeimfive | {
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"They are one of the reasons why some people drop out of CS programs in college, for one. On a slightly more serious note: a design pattern is basically a sort of recipe to solve a common problem -- only it's a partial recipe. These problems aren't anything \"big\" like \"write an application to do my taxes\", but they are small parts that occur in many different contexts. An easy example would be the `Publish/Subscribe` pattern. It describes how to be notified of a certain change or event. For instance, assume you're a chef. There's a cake in one oven, turkey in another oven, and a soufflé in a third oven. You don't want to walk around for an hour, constantly checking up on (\"observing\") each oven. No. Instead, you tell each oven to notify you when it's done cooking. While that's happening, you can go off and chop some vegetables or something. There are many ways to program something like this. But realizing that it's a common problem, and that there's a named design pattern for it, makes it easier to talk and reason about it. Kind of like two pastry chefs can talk about cake, without having to describe how to make a cake. They both have a pretty good idea of how a cake works. And because they both know about cake, they can say \"this cake was really nice\" or \"it only took 20 minutes to make\", or whatever the salient point is. It's a common misconception that you \"have\" to \"use\" design patterns, or that there is a magical list with \"all\" design patterns. The \"gang of four\" has famously published a bunch of them. But that's by no means all of them.",
"I'm familiar with C++, at least in that space, design patterns are just some common ways of grouping and creating classes that people have found useful. Rather than reinvent the wheel for certain needs that show up over and over in programming, they wrote down these design patterns that might fit what you're trying to do, and this saves you some time thinking about how to implement it. Of course, you have to have spent the time learning the design patterns ahead of time, at least good enough to recognize when it's a good idea to use one."
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77yhdn | How do radar detectors work? | Title. How do they even pick up signals when an officer is sending a laser beam your way? Wouldn't it have to pick up that one beam from the gun out of the entire surface area of the car? That's basically like saying that the officer is aiming directly for your detector or it's sensor (if that's how it works). | Technology | explainlikeimfive | {
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"A radar detector device has both a radar and a laser detector built into it. No different from how a smart phone often has multiple cameras, a microphone and speakers. The sensor that detects radar waves won't detect laser beams, and vice versa. A [laser speed detector]( URL_0 ) doesn't send out a pin point laser beam. It sends out an angled beam to make it easier for the officer to aim it at car and get a reflection. If that angled beam hits the laser sensor, your \"radar/laser\" detector will signal an alert."
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782ji1 | How do Radio Waves for cell phone signals penetrate into buildings if light can't travel around corners or visible light can't shine through opaque objects? Wouldn't you need a direct line of sight to the tower? | Technology | explainlikeimfive | {
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"Light and radio waves are all part of the electromagnetic spectrum. They don't all behave or interact with stuff the same. Xrays, infrared and microwaves are also part of that spectrum. They, like radio waves can be reflected like visible light but can penetrate certain materials."
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782rgj | Why so many videogames have the "glitching through surface and shaking furiously" bug and why does it happen? | Technology | explainlikeimfive | {
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"It's a result of a game's physics engine trying to approximate things \"bouncing off\" each other when they're trapped. So first what happens is the objects clip through each other, due to one of ten billion possible bugs or reasons. Exactly what gets 'em going through each other depends on the game. But what then happens is the game detects that these objects are touching & moving, and therefore attempts to bounce one the other way. If they weren't clipping together, this behavior would look like realistic physics. It's simplified from real physics but looks believable, so lots of games implement this. The problem? The new \"bounced away\" position is *still* clipping through the other object, so it qualifies as \"moving and touching\" again, and the game then moves it *back*, leaving it stuck in a loop."
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783k04 | Why does reducing the resolution of a video consequently affect the sound quality? | Technology | explainlikeimfive | {
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"No, that isn't the case at all. Sure, if you shrink a video by running it through some program on its default settings, without understanding what it's doing, then that might be what you get out. It doesn't have to be that way. If you learn how to use a command line processor such as [FFmpeg] ( URL_0 ), you can get exactly what you want. It can recode video while \"passing through\" the audio, for example.",
"They're two different settings, **but** most video services (like YouTube) assume that you're switching to lower quality because your internet was struggling with the higher bitrate version. So they scale the sound quality back too to make sure absolutely everything fits in the pipe, per se. If you're getting fancy with video encoding tools (like the other guys described) you can crank sound quality as high or low as you want."
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788bda | How did "cheater boxes" (cable descramblers) allow you to watch premium TV channels for free? | I had a few friends who had one back in the 90's that allowed you to get HBO and pay-per-view without actually paying for it. I always wondered how they work. | Technology | explainlikeimfive | {
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"Way back when, television was an analog signal. More accurately, it was a *series* of analog signals that your 100%-analog color television could use to produce a picture. You have three signals for color (your TV only looked at one if it was black-and-white) and a \"timing\" signal that indicated when it should start drawing a new line. The \"vertical hold\" was a sometimes-manual synchronization to that signal. \"Scrambling\" was really just that. Some of the signals were inverted, some of them were switched. But, fundamentally, you couldn't *add* in junk or actually do significant *math* to obscure the signal, because televisions simply didn't have the ability to un-do that and produce a working picture for your paying consumer. Likewise, before relatively powerful integrated electronics became available, it wasn't economically feasible to give a customer a powerful computerized set-top box just to watch some television. So your \"encryption\" was a scheme with only a few variables. Throw off the synchronization here, swap a color field here, and it would make the picture \"off\" enough to be unwatchable. But, likewise, once someone figured out your mechanism, they just had to create a relatively simply \"decoder\" to bring that signal back. TLDR: Analog encryption wasn't terribly complicated, but it was analog, so it required *hardware* as opposed to something digital, which might be more complex, but also could be done with a wider variety of hardware. Nowadays, everything is digital (because computing power, even for high-definition video, is so cheap) so analog encryption/decryption isn't a thing.",
"I built a couple of those for friends and family. The vertical sync signal was missing, so this box would create its own. You then had to fine-tune it manually to get a stable picture on your TV. Later, with the DirecTV systems, people hacked the plug-in cards that came with the box. The programming hardware was technically illegal in the US, but was about $80USD from a Canadian company. A friend was part of a \"dark web\" hacker group, and every time DirecTV changed the codes, they would be hacked within hours. Reprogram your card and you had everything. One thing you had to remember was that your box couldn't be connected to the telephone line, else DirecTV could \"call\" your box to see what it was doing. That's how they did remote fixes and upgrades back then. DirecTV finally came out with a new box and card system that couldn't be reprogrammed with the previous gear, so that was the end of that.",
"Everyone is talking about \"way back when\" and \"did\" but I have a cheater box rn? I have all of bell broadcasting for free...",
"For the digital age, things work somewhat differently. The encryption itself usually isn't broken but some other part of the hardware might have a flaw that lets you access the key data, be it a season interface, an firmware dump or just insecure key distribution. Once you get ahold of a valid key, you can rather easily emulate most common cryptography systems (in the end it's just some protocol plus AES) either in hardware or nowadays more commonly in software. Nagravision2 had such a major flaw that any key change would lock out pirate decryption for a few hours tops. Most paytv networks will weigh the suspected amount of pirate decryption against the tremendous costs of implementing a newer encryption system (usually that requires at least a smartcard change, tough luck if they went cardless and now have to exchange all the boxes). As long as the illegal decryption process is complex enough to deterr the average teenager, requires expensive hardware or at least some sort of fancy setup, they'll let people get away with it. More recently, cardsharing has been the typical way to go. Essentially, there's one valid and paid subscription in a cardreader connected to some sort of server (cable boxes, RasPis, full blown x86 servers, even internet routers like ddWRT boxes have been successfully used) and they handle the requests from the clients that connect via internet. Depending on the card in question, a dozen individual viewers is fairly easy to handle, using two or three cards can even result in as many viewers as your internet connection can handle (and that's a lot since only a few kbytes are sent and received every couple seconds). Recently though, providers have been switching to systems that pair the card with a particular box or have gone cardless alltogether - really annoying for people who simply want to use better hardware than the usually crappy provider boxes and do nothing illegal otherwise.",
"On the scrabmblers in the town I used to live in. Pin 4 of the chip would be 0 Volts on unsxrambled channel and 5 Volts on scrambled channels. So pulling the chip from the socket and bending pin 4 straight would let you watch anything you wanted.",
"Rockwell Collins in Cedar Rapids Iowa had a big controversy wenden management discovered a clandestine line in the plant where cheater boxes were being made. An actual line, with people assigned to it, making professional cheater boxes by the 10s of thousands. Selling them in the 80s fit like 30-40 dollars.",
"Boxes had EPROM chips. Cable companies sent EVERY SUBSCRIBER every channel that was available. Open box, dremel cut the epoxy chip that came with the box. Install $0.89 chip that you could buy hundreds of....",
"The best were the K band satellite hacks. Modded boxes for the 8’ dishes that enabled thousands of channels on dozens of satellites. It was like the selection available on the internet in the 1990s. Hundreds of channels of anything. The most fun we’re the news feeds - the remote camera feeds from the news stations. Watching the “Off broadcast” shenanigans of the feild reporter were fantastic."
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78949z | How does a Thermoelectric Generator work? | Technology | explainlikeimfive | {
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"What is really being asked is how the thermoelectric effect works, so I'll try and explain that. Imagine you had a metal wire that has either end held at a different temperature. The electrons in the metal act similar to a gas, where the electrons at the hotter end are moving faster and spreading out more. This causes a higher concentration of electrons at the cold end, which causes a voltage difference between the two ends of the wire. Note that different materials will generate different voltages, even under identical thermal conditions. A thermocouple or thermoelectric generator uses two dissimilar materials, with the hot ends attached together. This guarantees that there is a voltage difference between the two cold ends, which can either be used in power production or as a measurement signal."
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789udg | Why do cell phone batteries die faster the longer you own them? | Technology | explainlikeimfive | {
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"imagine your phone's battery has 100 cells in it brand new. when those 100 cells are fully charged, your phone's charge is at 100%. 3 cells lose their charge as you use it to browse eli5, 97%. now, those cells have a lifespan. after 3 months, 2 cells completely die and no longer can hold a charge at all. so now you have 98 cells in your battery. when those 98 cells are fully charged, your phone is at 100% because all available cells are fully charged. but that 100% won't last nearly as long because there are 2 less cells holding that full charge. so it'll get to 0% a bit quicker than it did with the full cells. so when 10 cells die off, you now have 90 cells holding a charge instead of 100. i made up all these numbers to paint the picture for you.",
"You store energy due to some electrochemical process. You put current in, the process happens, you take the current away and you can over time get some out due to the process now being reversed and happening on its own. Imagine you store energy in a spring made from metal. You draw it out, then put it in some mechanism that takes the energy out of the spring again to power something. You can put energy back into the mechanism by pulling the spring again. Repeat this a few thousand times and you'll notice that the spring isn't working as well anymore, the material has gone tired, wear has stretched it out a bit so it can store less energy than when it was new. Just imagine the same happens with your batteries. You load and discharge it so often that whatever is used in the elecrochemical process (the electrodes, the electrolyte in it etc) gets tired and stops working as well and can store less and less energy. If your battery could store energy to last your phone for 8 hours at the beginning it might be it's down to six or five after some years. Here's an [image]( URL_0 ), the details are not really important here, just to see what could simply not \"work so well\" anymore.",
"Think of rechargeable batteries like balloons. You inflate them then you let them go and they whizz delightfully around the room or in the case of batteries allow you to flit around Reddit. Anyway, balloons, like anything elastic, eventually lose their stretchiness and you cant use them anymore. Batteries are very similar. The exact cause of the decrease in storage capacity from repeated use varies between different battery chemistries but the end result is the same, less Reddit per charge."
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78de54 | Are sensors mechanical or programmed responses? | My SO and I are at a standstill and I need some help. We recently watch "Ex Machina" and started a discussion regarding the AI's skin and how it would work. I believe that the AI's skin would be like our own, as I understand, and built on a redundant system of tiny sensors that would be stimulated to send an electric signal to the brain by design. My SO is arguing that the sensors must be "programmed" so that the signal is transmitted upon stimulation. The point I'm making is that "programming" is not needed if the skin is built/designed to respond to stimulus and the process is mechanical. I would like to know how if using "programming" as a way to describe the process of skin sending signals to the brain is either incorrect or correct. | Technology | explainlikeimfive | {
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"If it's an electromechanical device that can only do one thing, it's *designed*, not programmed. I mean, it's a completely fictitious device, so we can only speculate as to how it'd actually be built. There could be some programmable device in there that collects input from all the individual sensors & then relays that as a signal to the central processor.",
"It'd be more apt to describe the brain as programmed to interpret certain sets of electrical signals as pressure, pain, heat, etc. Our own skin reacts in such a fashion. Nerves aren't \"programmed\" to do anything. They simply react to stimulus and produce electrical signals the brain later interprets. Mechanical sensors can be built the same way. Thermocouples, for example, do not require any programming. They get hot, they produce an electrical charge. It's a purely physical process. Piezoelectrics are similar. That isn't to say you can't program a wide variety of sensors to react to different stimulus. Really I suppose it would come down to the unique requirements of your synthetic skin."
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78erng | How do defibrillators work? | And is it possible to repeatedly stop or start a person's heart using them? | Technology | explainlikeimfive | {
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"Haha at last something relevant to my work. I work for a company that makes defibs. So a bit of background about hearts. Hearts are basically a bag of blood surrounded by muscle. Muscles are activated by electrical signals. In normal muscles, they are activated by nerves usually coming from the brain, but in the heart the nerves come from a separate controller on the heart itself. So this central controller controls the heartbeats. _Fibrillation_ is when this central controller goes astray and uselessly quivers the heart. How to fix it? You can send a huge jolt of electricity through the heart, shocking it to reset back to normal. This is of course called **De**fibrillation. _Common misconception #1: you cannot use defibrillation to restart a heart in **ALL** heart attacks or cardiac arrests!_ Only in ventricular fibrillation (VF) and pulseless ventricular tachycardia. If the heart is completely stopped, using a defib won't help. _Common misconception #2: Automatic External Defibrillators (AEDs) that you see in malls or public places work like the movies; when you press the button, it will immediately jolt the patient._ Modern AEDs are much smarter nowadays, they actually analyse the heartbeat of the patient, and will advise if a jolt is warranted. So if you ever have to use one, don't panic even more because it didn't deliver the jolt like you expected. Last point: make sure that the skin of the patient is dry before pasting the electrodes on the skin. And of course don't touch the patient when the jolt is delivered. And to answer your question about repeatedly starting and stopping the heart, possibly not, although I'm not a doctor. Reason is that electrical shocks might completely stop the heart, which a defib will not be able to start again. Basically comes back to the specificity of conditions where defibs are useful. Disclaimer: I am not a doctor or expert. Always consult a professional or read the instructions for use.",
"Defibrillators actually don't start a heart. What they do is force the heart to return to a normal rhythm, in the case of dysrhythmia, such as tachycardia. This can prevent a heart attack from occurring, but it cannot restart a heart that has stopped beating."
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78hl1u | How do cryptocurrencies become regulated? | I've recently read news about China blocking ICOs from happening. I've also read about Gab and how they are the world's first Reg A+ ICO. Is this a good thing or a bad thing? Does this defeat the purpose of being decentralized? | Technology | explainlikeimfive | {
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"China is a special case. There is no Internet there, only a China-subset Internet. When they block ICOs, they are saying companies inside their Great Firewall can't participate in them. If there are regulated and non-regulated ICOs, then users can vote which they prefer, by which they buy. It's still decentralized, even if some players in some coin offerings are working under central regulators.",
"You can't regulate a cryptocurrency. You can regulate an exchange however, requiring everyone to show ID and provide documentation to prove income. You can regulate or block an official investment fund into a cryptocurrency too. They can regulate the fiat currency being used to buy crypto. Compare to gold. You can regulate the shops that buy and sell gold, or regulate people on wall street that invest huge amounts of money into gold. However you can't regulate gold in the fact of going door to door and making sure only a set number of gold exists in the world. And in the case of bitcoin, since bitcoin is protected by a private number, you couldn't force it away from someone's hands without going through the person first. Even in a crazy situation where the bitcoin rules changed and the government was in charge, people would easily move to a separate fork of bitcoin, or even move to litecoin, peercoin, or a brand new coin.",
"Crypt-currencies are very hard to regulate, by design, because there isn't any single entity to point guns at. You have to point guns at everyone. Anything that can't be controlled by pointing a gun at someone can't be regulated.",
"The gov says what any business can and cannot do. The risk of doing something that gov says you can't is at best a fine. You can go to jail or worse. If China says you can't trade cryptos, then you risk fine, jail or worse for doing it. Business owners won't risk it. Private people might...until someone gets caught and it ends up in papers....or don't end up in papers and you never hear from them again. China gov much less affected by local population vote pressure. If gov says marijuana possession with intent to sell is death sentence, no amount of public outcry changes it."
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78kc0v | How do they track baseballs during a game and turn it into a visualization for the audience? | Technology | explainlikeimfive | {
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"There are three cameras set up at known locations in the ball park and the distances and angles between them, the plate and pitchers mound are known precisely. Each camera records the ball as it moves from the pitcher toward the plate and the location in each camera is combined in order to calculate the exact position, speed and even rotation of the ball at each instant in time. A different set of three+ cameras record the ball once it is hit by the batter and do the same calculation for distance, altitude, angle, etc. Source: [Pitchf/x]( URL_1 ) was the system used by MLB through last year, now [Trackman]( URL_0 ) does it, but pretty much the same way."
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78p1w8 | How do commercials work? | How is the order decided? When a company owns a lot of channels, how is it decided which channels will show the commercial and which ones won't? Why do some national stations show the same 5 commercials all day? | Technology | explainlikeimfive | {
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"The advertiser specifies what channels and what shows they want their ad on, and how many times. They can choose a single show, or a category of shows based on type or based on audience statistics."
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78q8aa | Why is it so hard for game developers to scale UI's across multiply screen resolutions? | All other game elements get scaled just fine (ex. going from 1080p to 4k). You're character and the environment stay the same size on the screen. However, the UI (HUD, mouse cursor, option menus, etc) get shrunk down to 1/4 size. Sometimes, there is a UI scaler included in the options, but most of the time, it seems to cap at 140%. | Technology | explainlikeimfive | {
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"Because it requires more code and therefore time and money to make a 'good' UI. It's comparatively much simpler to fix everything in place or scale it by a fixed amount for different resolutions. If you're asking why they never include a stronger UI scaler it's that there's just not much demand for it. I'm sure you'd love it but the vast, vast bulk of their customers aren't going to be using such a large screen that the UI scale becomes a problem.",
"I've had to deal with this problem in hobby projects. There are really a few reasons for this: 1) As soon as you change aspect ratio (say, between a 16:9 and 16:10 screen), your proportions all change. My \"put this thing 10% from the left edge of screen\" may look great at 16:9 but it may bump into another UI object in 16:10. Same problem with font size - how large should a font be for each resolution? Without testing them individually, I need to just come up with a math formula and hope for the best. This just plain-old isn't as good as testing every combination one at a time and with different aspect ratios changing font sizes is just a nightmare of trouble. 2) There is a bit of tediousness and laziness to it. Getting everything to look right in every possible resolution is EXTREMELY time-consuming and probably the least-interesting thing you could possibly be working on. Nobody wants to do it, it's expensive when you're paying a team to make a TON of different art assets in different aspect ratios and paying a DIFFERENT team to test all this and get you all the numbers you need for every bloody piece of UI in the entire game. It's not fun, it's extremely time-consuming and...Where do you draw the line? How do I decide what resolutions to just not support anymore? Should I just ignore anything below 1366 x 768? Should I even bother trying to support THAT resolution when it's SO much lower than 1080p? But so many entry-level laptops use it, so I should probably test for it, right? Or should I? Should I bother fully testing 1920x1200? It's not common but it is out there. It's even worse with phones when practically every phone ever released has a different resolution/aspect ratio."
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78q928 | What happen(s/ed) to all of those crazy "future technologies" we hear about, but suddenly drop off the face of the earth? | Technology | explainlikeimfive | {
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"All of the above. Some technologies work well in the lab, but can't scale to industrial applications. Some are just too expensive to pursue at this time. Some are bought and sat on by companies until they can switch their business models to take advantage of it."
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78r6jc | How can touch lamps be sensitive to touch while simultaneously being grounded/earthed? | Technology | explainlikeimfive | {
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"There can be a touch surface which is grounded via a low resistance inductor. The inductor would not prevent the low level, high frequency signal used by the touch sensor from working. Inductors (block or reduce) the flow of AC."
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78rris | packet buffering | why does it happen? and how? | Technology | explainlikeimfive | {
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"A train just arrived at the station. Lots of people leave the train. The escalator up can only load one person per second. All these people are now waiting for the queue in front of the escalator until it is their turn. That is what packet buffering is: More packets arrive than the outgoing link can transmit. Possible solutions are: * Get another escalator: Now you can load two persons per second! * Get smaller trains more often, that way less people are waiting each time as the load gets distributed over time. * Get the smaller or the important people on the escalator first."
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78uaed | how do self balancing bikes work? | Eli5: such as Google's self balancing bike. Or I've seen a concept of a motorbike that can't fall. How are they able to offset the weight when the bike is unbalanced? What is this magic? | Technology | explainlikeimfive | {
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"I'm not sure which Google bike you mean, but if it's this one: URL_0 I have to dissapoint you because it's an April 1st joke...",
"In short, angular momentum. (On mobile here, so sorry for any typos in advance) So just like how an object moving in a straight line will continue to do so into an outside force stops it (like friction), objects that spin will want to continue spinning. The first is linear momentum, the second is angular. Whenever an instability in the spin happens, the entire system will shift to try and maintain its overall rotation. This is why it's easier to stay upright on a moving bike compared to a stationary bike. The wheels want to keep moving around the axle. As soon as you start to tip, the wheels are now also rotating in another direction. Any bike with spinning wheels will try to right itself some, but is limited based on its rotational speed. The super fancy bikes will have gyroscopes installed that can be sped up via computer controls to counter and rotation due to falling over."
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78ug78 | How does a program know what I've clicked on? Is it constantly checking each and every button region for a click? If so, could increasing the number of buttons on a screen slow down a program dramatically? | Technology | explainlikeimfive | {
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"Programs have mouse readers; when you click the mouse button, your computer sends the program the x,y coordinates of your mouse and the program \"registers\" a click in that location accordingly",
"You don't need to check continually for a button click and location you only need to check when the click actually takes place. So \"On click\" check what mouse button was clicked, where it clicked and what the active application is and then decide what was clicked. You don't check per button but per click.",
"Developer here, When you move the mouse, it's circuitry produces a message it's going to send down the wire or over the air to a receiver. This event will eventually trigger an interrupt. An interrupt is either a hardware or software event that tells the environment to stop what it's doing and address this issue immediately. Interrupts are enumerated, and there's a table of offsets to program instructions that handle that kind of interrupt. So whatever software gets kicked out of the CPU core, the message is dispatched to the hander which gets executed. The event gets passed to a hierarchy of event handlers (a specific kind of function called a callback in the more general case), software you're running that is even interested in these sorts of things. Typically it begins with the top window that got clicked on (the desktop itself is a window) and on down, through other programs that might be interested. What the program does is up to what the developers put in their programs. If the click is in some region that doesn't do anything, then the callback is done. Otherwise, the program goes on to do something about it. GUI programs have what is called an event loop, which enters a \"blocking\" state. It's waiting for a message to come through; in the simplest case, the program gets no CPU time because there's simply nothing to do. The OS has a \"scheduler\" that is involved in managing which programs get how much CPU time in what core, and the program gets woken up. In the loop, you decide what to do, if anything, do it, and go back to the beginning of the loop, waiting. This is event driven programming, and in a very simple model of a computer, the CPU will have an idle instruction, and the whole computer could get away with literally doing nothing until an event triggers action. Your desktop CPU is far more complicated than that, of course, so no such thing like this would happen on it these days. Even the blinking of the colon on the clock is event driven, causing a cascade of activity. There is a way to do the same thing in a non event driven, non blocking way, and that's polling. What this is, is you store the last known state of the mouse, and put in a loop logic that goes to the mouse and checks if there's a difference, if the state changed. \"Are you different? Loop. Are you different? Loop. Are you different? ...\" The CPU will cycle as fast as it can, just checking. The problem is a scenario where the mouse moves, and then move back, or a button is clicked then released, before the program had a chance to check again. Polling is just a technique in the toolbox, and there are scenarios where that's the only option, for example, if you wrote a program that checks if the TOS of a website, software, or service has changed - you know, if you've read one of these things, they say subject to change without notice... So anyway, polling isn't necessarily a good fit for a mouse."
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78x8jt | What do cell phones do with the information it gets from SIM cards in order to make a phone call? | Technology | explainlikeimfive | {
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"Take it roughly the same as how authenticating yourself on a private, wireless network. Your SIM card ID is a username, your PIN unlocks the SIM card's \"password\" equivalent (your pin isn't used on the network, it unlocks the second encrypted part needed to complete the authentication). Once the SIM full ID is unlocked (and your phone accessible), you get access to your account's credentials on that network (remaining credit and the like) and you can make calls (other than emergency ones). And for the reason about Vsims like VSCA or any other .. these take time, it has to come from cooperation and make the insane paperwork, adopt standards for network operators AND phone manufacturers and face the potential loony, obnoxious one who wants to do his own thing with zero standard whatsoever (hello Apple) and will probably make the others do the exact same thing : divide & conquer (hello everyone else)."
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78y8gu | On Windows (and possibly other OSs), why is the system's only recourse in the event of a software error to completely nuke the program? | Technology | explainlikeimfive | {
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"It is the latter option. Bugs, errors, and glitches happen all the time, and most often they end up fixing themselves or just terminating and trying again. You can look at countless video games to see this is the case. They rarely break programs. It's just that occasionally one will crash you out.",
"That's really not how it works. It's up to the program to catch it's own errors and deal with them. In the Olden Days, if that didn't happen then that program could take other programs (including the OS!) down with them. So now OSes put a cage around programs. When they misbehave and can't handle their own mess, the OS nukes them.",
"> system's only recourse This is simply not true. Most software errors *don't* result in the program being nuked. It just goes on running, with or without an error message, and with or without a visible impact on its action. For example if a program asks for a nonexistent font, typically another font is used, and it just goes right on running. You're just looking at the *most severe* errors.",
"When a bug happens, it's something unforeseen by the programmer. It means that the program is an unexpected state, or a condition thought to be impossible to reach. When this happens, the program (and the system) have two options. They can either kill the program immediately. Or, they can try to muddle along and make things work as best they can. The problem with trying to muddle along is that you have literally no idea what's wrong with the program's internal state. And letting it continue to run could cause a lot more damage, like unrecoverable data corruption. Therefore, it is better to just kill a program immediately when it runs into a bug whose occurrence was not foreseen. Think of it like driving your car on the highway. You press the brake, and you are terrified to find out that it doesn't work. You can either try to gradually slow the car to the stop with the emergency brake, then get out and take the bus. Or, you can try to keep driving, using the emergency brake as necessary. Which sounds like a better plan?",
"> Or am I simply not seeing the countless errors and bugs that the software does continue on from as normal, and is it only the Ebola-level errors that cause the software to forcibly close down? This is the case. Programs are generally written to deal with a lot of \"normal\" scenarios. But there are other scenarios that aren't normal, but they imagine they could happen. For example, if you let users browse files, and then let them delete them, sometimes you'll encounter an issue where the file no longer exists (it was deleted in another program). That's often referred to as an \"exception\", it's not common, but programs should be written to handle those situations as well. So really good programs will handle all of the conceivable exceptions that their code could cause. BUT there are always some exceptions that can't be handled in your code, not in a meaningful way. For example, if your program uses up too much memory, there rarely is a way to recover, so it'll crash. So what you're seeing when this happens is one of three things: * There was an exception they could have handled, conceivably, which they failed to. * There was an exception they noticed, but realized if this exception happened, there's no way to recover * There was an exception they couldn't catch (like out of memory) and the program basically gives up out of their hands. I'd wager the majority of the time, it's the first case. It's really hard to catch all the exceptions.",
"When you get that message, it doesn't mean \"there's a bug in the software\". Windows doesn't know or care how many errors there are in a piece of software. What it cares about is when the software gets so buggy that it tries to step on Windows' toes. That message most commonly indicates that the application tried to access memory that didn't belong to it. When that happens, the OS is notified, and since the application doesn't have access to the memory location it's trying to access, there's no option but to halt the program. Programs can contain as many bugs and errors as they like. The OS only stops them when they violate its rules and try to do something they don't have permission to do. So if you want an analogy, think of the OS as hosting a party. As long as the guests are just getting drunk and vomiting over themselves or accidentally sitting on another guest's glasses or spilling beer on the floor, that's ok, you can live with that. There's going to be some cleanup afterwards, but that's to be expected when you're hosting a party. But if they start actually breaking your furniture, or if they start trying to knock down the wall to the neighbor's flat to see what's in there, you're going to have to stop them and kick them out. Once they start trying to cause actual damage to your property (the OS) or to your neighbors (other applications running on the system) then it's \"Party's over, everybody go home, it's been nice seeing you, but you've got to leave *now*\". At that point, you simply can't tolerate what they're doing, and you have to shut the whole thing down. And that is what this error message means. It means that the program wasn't just doing stupid things, it was trying to do something that would harm the rest of the system."
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7907m5 | difference between C++ , C# and Java | Technology | explainlikeimfive | {
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"I'm primarily an Embedded C and Python programmer, so please take this into account when reading this. I do have experience with C++ and Java, and just a tad in C#. This is meant to be an overview, and I'm open to suggestions from programmers with more experience. To explain the differences, we first need to address the main similarity: * All 3 are object oriented languages. Now, the differences: **Portability**: * Java was created to be easily portable between systems. In theory, code that works on a Mac will work on Windows, Linux and any other supported systems. This is not completely true, but at least it makes portability easier. [Note: this applies to Java SE, there are other versions where this might not apply]. * C# is mostly used for Windows, since it was designed by Microsoft. * C++ is in the middle. You can create a portable program as long as you don't use any specific functionalities (not easy if you have a GUI) and a compiler that works for different systems (also hard). * C++ and C# are \"descendants\" of C, and share several things with it, like syntax. Java is it's own platform, and has a (somewhat) different syntax and its own file extensions. **Compilation**: * C++ and C# programs need to be compiled before they can be executed. And there are different compilers available, each with its flaws and strengths. * Java does have to compile too, but the output is a \"plataform-neutral\" byte-code that is then run through an interpreter. This is what allows Java to be easily portable. The interpreter takes care of the specifics. * C# is compiled into byte-code too (called MSIL). **Efficiency & Resource Management**: * C++ is the most \"barebones\" of the three, it does not as much functionalities by default, and tends to consume less resources. The downside is that you'll have to spend more time coding. * C# and Java have garbage collection built into them. C++ does not. This is a really simplified explanation, I hope it's useful though! EDIT: better explanation of C#/Java byte-code.",
"They are all object-oriented descendants of C. C++ came first and compatibility with the C environment is both a feature and limitation. Typically it's compiled fully into local machine code. The early compilers just translated C++ to C. Java has C-like syntax but has much less in common under the hood. In particular, it was designed with portability in mind and so it's almost always compiled to byte-code which is then interpreted. C# is what happened when Microsoft failed (for legal reasons) to embrace and extend Java. That's a somewhat cynical view but C# is pretty definitely a Java descendant, learning from people's experiences with Java and adding improvements."
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790ya0 | What happens to a charger that's plugged into a power outlet but doesn't have a device attached? | For example, if I plug in the power brick for my computer into a power socket, but I don't attached the charger to my computer. What happens to the brick while it's on "idle?" Is it somehow being damaged by me leaving it in the power outlet while I'm not using it? Edit: Welp, I finally understand what everyone means by 'RIP Inbox.' Though, quite a few of you have done a great job explaining things, so I appreciate that. | Technology | explainlikeimfive | {
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"Wall adapters and chargers are almost always AC to DC adapters. What they do is take the electricity in the wall and change it from whatever periodically-changing voltage is standard in your country (AC) into a constant voltage (DC) of a certain amount. A simple way to do this is to change the voltage with a transformer and then force it to always move in the same direction. A more complicated (but more efficient) way to do this is to store it as a magnetic field for a very small fraction of a second and then bring it back as the correct voltage. In either case, the final voltage is regulated by capacitors which store energy and try to keep the voltage steady. Well, that's the ELI5 version of it. Anyway, theoretically an AC to DV converter circuit shouldn't draw any energy out of the capacitors which keep the voltage steady when there's nothing plugged into it, but in reality it's not so simple. The components that make up the circuit are imperfect which means it will always use a little bit of energy when plugged in. In addition, many power bricks have a LED on them which shows that it's plugged in, meaning that you always have some tangible amount of power being used. TL;DR: It will always use a small amount of power when plugged in, but you won't harm the adapter by doing so.",
"Not much. It does draw a minimal current, but it's neglible. It won't affect the lifespan in a meaningful way (the charger is probably one of the last components in the computer to die anyway...). So, don't worry about it.",
"Why does my power brick make a high-pitched noise when my phone is fully charged, but still connected to the charger? Edit: I'm not a native speaker, sorry. Thanks for your corrections: my phone charger is not a \"power brick\".",
"Typical non-english disclaimer: sorry for destroying your language; I am french Canadian. Edit: In this example, I am referring to a 5V usb cellphone charger. However, this applies to most [chargers]( URL_0 ). A wall charger is basically three components (before someone start to bash on me, I understand modern switching setup may have different designs, but understand this is ELI5). & nbsp; 1. A step down converter (convert 100-240V to something like 7-9V) 2. A AC-DC converter (Wall electricity to battery like electricity) 3. A regulator & nbsp; So, you have 3 components, with different roles that work together. Electricity coming from the wall (also called \"Main\") has to be converted from its original state, which is \"vibrating\" at 50-60 hertz and could be anywhere from 100V to 260V (main is actually not regulated, so it may vary a little during the day, and depending the area you are). To give you a rough idea what 60hz is, it's the ZZZZZZZZZZZZZZZZZ sound an old neon makes. & nbsp; It is much easier to work with smaller voltages than high voltages, specially when confined in the small area of a wall charger. Since we want to end with low voltage, we start that way to simplify the rest of the circuit. That is the job of the step down converter. & nbsp; Once the step down converter has lowered the voltage to something, say, 7-9 volts, we want to turn the AC (vibrating) electricity to DC (continuous). This is usually done by a single inexpensive part. & nbsp; Once we have low voltage DC power, we simply need to regulate it. This is where the regulator comes in. The job of this part is to control the flow of electricity in order to maintain a constant voltage (5V in our case) across load. This means that regardless if your phone is connected or not, the output of the wall charger will \"always\" be 5V. & nbsp; So, to answer your question, if you leave your charger disconnected, your regulator simply keep a 5V on it, wasting a ridiculously tiny amount of electricity (1-5 cent a year depending the pricing of electricity in your area). Some smart chargers may have a sleep mode, turning themselves off completely unless connected. Regardless, a properly designed wall charger will never suffer any damage from staying disconnected. & nbsp; Some people have asked what was the whistle that could be heard when the phone was full or disconnected from the charger. This is what we call \"coil whine\". Basically, a switching regulator works by pulsing electricity through a coil, which create an magnetic field. Under very low load, the pulse becomes \"slower\" (simplified), which makes the coil vibrate in a frequency we can hear. High quality manifacturers will fix that by gluing the coil during assembly, or using a higher frequency regulator. Regardless, this is not an indicative of a failing device, you can still use it without any issue. BTW, this is my first comment on ELI5, I hope it's clear enough.",
"Wall chargers are like a good woman. Think of a man as the device you plug in (resistance). The more attractive men find her (voltage) the more men (current) she will attract. The more men she attracts (voltage x current) the more power she has (watts). If she is a 10/10 (high voltage) there's a potential that she is going to attract way too many men (current). Being able to attract that many men is too much power (watts) for any one woman to have so she breaks down and cries (overload). Without any men at the bar (resistance) there is no load on the woman (your charger) and subsequent nobody walks up to talk to her (no current). No men flocking over her means she has no power (watts). She's still super attractive (high voltage) though so be careful around her!",
"what about if the charger (without a device) is plugged into a UK wall socket that’s switched to ‘off’? I’ve always wondered what on/off means in the wall socket context",
"Most chargers use transformers. A transformer is kind of like a water wheel. As water (current) flows by, it starts things moving (electrons) which power your device. If the device is unplugged it would be the same as just stopping the wheel. Current will continue to flow past unhindered. Edit: move an r",
"For starters your charger is drawing power from the wall at all times regardless of if your device is attached or not. But the amount is the important part. When you plug in your cell phone or laptop charger there are parts inside (keeping this EL5 as I can) that use AC from the wall and convert them to DC. Your phone/laptop then uses that DC to charge and power it's component. When your device is not attached you are drawing less (much less) power but technically the charger is drawing what we like to call quiescent current current. This quiescent current (or no load input current) is what your asking about. As other people in the comments have posted we are talking less than 5 cents a month. The math is simple and many people here in the comment have explained it well. Take your quiescent current times your input voltage (about 115v in america) and that gives your power. Then multiply that by time. In a perfect world your charger would draw zero power when plugged in, but due to the imperfections of electrical components and this not being a perfect world....you know. With regards to safety, and things of that nature, that's a nother conversation to be had. Edit: regarding damage, technically you are \"damaging\" your power brick when it's plugged in. But we are talking damage that takes years. By plugging in your power brick your using it which reduces it's life time, but this can be said about any electrical components in existence. More likely than not the designer of your power brick took the time to evaluate the details here. All and all your not going to destroyed your power brick sooner by leaving it plugged in. This how ever is not true for things like batteries and is another conversation in it's self. Edit: Tldr: your charger draws a tiny amount of power when you plug it in the wall with nothing on the other end. Your power brick won't die on you just cause you leave it in the wall all year.",
"Your wall power will be brought in to the converter, pass through a step down transformer, rectified using a bridge rectifier, filtered and the resulting DC voltage will be regulated to 5vdc then stored in the output capacitor. The resulting power is potential. If there is no current draw the unit will not be using the power, it just sits there at the ready. No harm is being done at this point. The components are barely working until current is pulled. But there is usually a led installed on these power bricks which will pull come current. Negligible amounts but some all the same. Source: work on magic",
"Mine makes a ticking sound while no devices are attached, so in the \"idle\" state still there is electricity going through it's circuit. Not a pro here, but probably that electricity going through it's components it will eventually reduce the lifespan of the charger."
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791ns9 | Why is digital storage getting better every year? | How is it that 15-20 years ago, I had to save up for a month in order to buy a 1GB Hard Drive that weighed over a kilogram, when I can now find microSD cards with 400GB capacity? Is there a limit to how compact these things can get? Will I be walking around with thousands of terabytes in my pocket within the next decade? | Technology | explainlikeimfive | {
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"Technology is refined, step by step. Moore's law applies pretty well to storage, so expect a doubling in capacity every 18 months. Is there a limit? Sure there is (storing a bit requires at least one electron, with current scientific knowledge), but we aren't close to it yet."
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791pno | SSD's. If I have a 100 GigaByte SSD, does that mean there are (roughly) 800.000.000.000, or 800 billion transistors inside of the SSD for storing data? | I'm trying to figure out how SSD's work. Just to explain my numbers: * 1 byte is 8 bits. * 1 gigabyte is 1 billion bytes which is 8 billion bits. * 100 gigabytes would be 800 billion bits. Or do I have this completely wrong? Like as far as I understand, an SSD has a bunch of transistors which can either be 0 or 1, and that's how they store data. | Technology | explainlikeimfive | {
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"6 transistors per bit in an SSD, so, in your case, 4800 billion transistors. It's actually quite impressive, it's over 500 times as many transistors as there are people on earth.",
"More actually, a transistor in itself doesn't store any data. A quick googling tells me there are typically 6 transistors used to store a bit. I am not the one to explain to you how they need to be arranged to actually store memory though, hopefully someone else can fill in on that part... There are also different technologies, IIRC the cheaper ones use an MLP technology, which means multiple voltage levels can be stored, to each set stores 2 bits but requires double measurements to read the bits, that probably changes the number of transistors per bit.."
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792n9k | Why has Hdr been so common in cameras for so long but is only now beginning to move into mainstream TVs, Smartphones and games consoles? | Technology | explainlikeimfive | {
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"They're different technologies. The HDR in cameras involves taking two shots at high/low exposure, then merging them to a single photo. The HDR in video displays refers to the ability to show a wide range of brightness.",
"HDR-photos are typically just composite images of several photos, taken with different exposures. What proper HDR is about, is being able display/capture truely dark and really bright parts of the image, both at the same time. This is what's new, and it's not easy."
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7932me | How do Youtubers that make "movie mistakes" videos monetize their videos? Aren't they using someone else's creation to make money without their permission? | Technology | explainlikeimfive | {
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"In the US there is a \"fair use\" doctrine which allows the quoting or in this case inclusion of copywritten material for such purposes as criticism. Typically this would be used for things like reviews but a \"movie mistakes\" video still falls squarely under the category of criticism and therefore fair use."
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794aep | Why do CRT TV's use so much more power than the normal TV's of today? | Technology | explainlikeimfive | {
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"The way they draw the image is kind of crazy. The emit a powerful beam of electrons from a device called a cathode, and then use powerful electromagnets to steer this beam all over the phosphor-coated glass screen, making various points glow with energy. That takes a lot of power."
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794yfw | Difference between RFID and NFC tags | Technology | explainlikeimfive | {
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"NFC is kind of a subset of RFID. RFID - Radio Frequency IDentification is just a means of communication with small devices. It's usually referred to when talking about RFID tags with unique serial numbers that you can use to track items, vehicles, people, or animals. There are active forms of RFID, but they're fairly rare as compared to something like an RFID tag for a cow that you can read as the cow enter the chute to the market truck. NFC - Near Field Communications. A specific method of communicating at a particular frequency over a very short range (20cm is the specification). NFC allows two-way communications between the devices, but doesn't require it. If you wanted to put an NFC tag on a cow, you'd have to have a reader that got right next to the cow's ear versus having an RFID reader that can read it from 5 feet away."
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795hvd | Fingerprint scanner (Touch ID) hashing | Specifically, explain it like I completely understand hashing. I understand that when you change the input to a hash function a tiny amount the entire output changes. This is what I don't get: if a hash of the fingerprint is stored then doesn't a tiny variation on the positioning, lighting etc of the scan completely change the output which is then compared with the stored version, thus marking it as incorrect??? | Technology | explainlikeimfive | {
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"URL_0 > The raster scan is temporarily stored in encrypted memory within the Secure Enclave while being vectorized for analysis, and then it’s discarded. The analysis utilizes subdermal ridge flow angle mapping, which is a lossy process that discards minutia data that would be required to reconstruct the user’s actual fingerprint. The resulting map of nodes is stored without any identity information in an encrypted format I think the idea is that it's always just looking for the same set of nodes (or rather the subset that is in contact with the sensor during a given scan). Each individual scan may be slightly different, but it's discarding all of the stuff that varies and just looking for a few static parts.",
"Your fingerprints contain a lot of little details that make them unique, that's how we're able to consistently identify different people using them. These details are called minutiae. When the scanner picks up your print, it identifies the various minutiae and can use those to create a consistent hash. Most computer fingerprint systems will do this by comparing the presented fingerprint against a database of fingerprints, but in order to maintain security, a biometric security system shouldn't do that, instead a minutiae point called the pattern, the overall shape of the fingerprint, can be used to indentify the center and rough orientation of the print, from there the computer can then check the other minutiae points relative to that center to calculate the hash and ask the computer to compare the two."
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795pdv | How is the Crocodile Dentist mechanically random? | Technology | explainlikeimfive | {
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"text": [
"Imagine a disk with holes under the teeth. The teeth aligned with holes go down. The tooth that doesnt align with a hole triggers the mechanism. Resetting the jaw spins the disc (randomly landing on a new sore tooth)"
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797ezg | Why is standard compliance important with regards to HTML and CSS? | Technology | explainlikeimfive | {
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"Internet Explorer 6 taught quite a few businesses why standards compliance is important. IE 6 was included with Windows XP and this just happened to occur as everybody decided webpages were a really good way to perform certain businesses processes. When these businesses went to develop these pages they only cared about then working in the new Windows with IE 6. It just so happened that IE 6 also had some non-standards compliant \"features\" and supported the now discontinued ActiveX. IE 7 comes out and suddenly those webpages don't work. Microsoft thought they had locked up web browsers but then Firefox came along and proved them wrong. Firefox was much faster and had more features so people started moving over to it. With Firefox quickly eating away at IE's market share Microsoft had no choice but to make their browser standards compliant (somewhat). Firefox was standards compliant and it's rising market share meant more pages were written without hacks to look right in IE 6. Without the IE 6 specific code, page elements would end up in the wrong place, making IE look broken (which it was). So why did everything break in IE 7 but worked fine in IE 6? Those special \"features\" in IE 6 I talked about were actually added on purpose to break support for other browsers. Microsoft assumed they would control the browser market and completely screwed themselves. If they left in support then web pages would look broken. If they took it out then businesses would not upgrade IE because it's cheaper to stay on IE 6 than redevelop their software. It was not until much later versions of IE that they detect what version of IE the page was written for. Microsoft did not learn their lesson. Each new version of IE had some very weird ideas of what standards compliant meant, breaking things that worked fine in the previous version of the browser. This lasted until the last version of IE when they eventually called it quits and started over with Edge. Meanwhile Firefox did not have these problems. Because they were standards compliant they did not have to worry about anything breaking in an upgrade. People could move to the newest version of Firefox knowing their favorite web pages would continue working exactly as before.",
"Standards-compliance is important because it means that other people can adapt your work in ways you might never have expected. For example, instead of you writing a page that's compatible with a certain version of Internet Explorer and *may* work on other browsers, you can write a standards-complaint page that will be compatible with *every browser* (that is itself compliant with that standard), even ones that haven't been developed yet! You also impose a long-term cost on yourself by not being compliant. It's tempting to treat one browser specially to make a quick fix for a problem or implement a feature that browser normally doesn't support. But once you have special treatment for four or five different browsers, maintenance becomes a lot more difficult. And what works for one browser now may break something for another browser. You may even have to maintain different versions of a page for different browsers. If you're standards-compliant, writing the page is your job, and you don't have to worry about the browser developer's job.",
"You want your website to look the same on all browsers. Using non-standard styles in your CSS or using HTML tags in \"creative\" ways may only work on one browser but not others. Sometimes non-standard code will even make your website completely unreadable on certain browsers."
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798prf | Why are screen resolutions like 1920x1080 rather than 2000x1000? | Technology | explainlikeimfive | {
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"Originally, the standard was 4:3 since several experiments found that the human eye’s field of view (FoV) was of the same ratio (155° H x 120° V). Hence it was continued as the standard for film, camera and later for TV as well. Now, Hollywood industry had to be something different compared to the home television. As a result, Hollywood came up with widescreen movies with more picture content which created the wow factor and was successful in drawing back crowds to theaters. Since there was no standards body back then, several aspect ratios started cropping up across different film houses, some of the popular ones being Panavision ratio of 2.20:1 and a much wider format called CinemaScope of ratio 2.39:1. This way, Hollywood managed to get back its audience for movies, while casual viewing at home like soap operas & news continued with the 4:3 ratio. Going forward, to accommodate this wide array of aspect ratios under a singular standard, the geometric mean of the extreme ratios (1.33 & 2.39) was taken at approx 1.78, rounded to whole numbers as 16:9. This was done to efficiently cater to all the aspect ratios under the same screen by minimizing the presence black bars across the entire ratio spectrum. Following this 16:9 ratio, screens were manufactured. The resolution or detail (1280x720, 1920x1080) was just a measure of the horizontal and vertical pixel array size and correspondingly, picture clarity."
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799b59 | What are hooks in computer programming? What are they used for? | Technology | explainlikeimfive | {
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"Hooks are a type of function that allows a base system to call extension code. They’re used to allow other programmers to change or extend the behavior of an existing program or system. Every Chrome (or other browser) extension is possible because of hooks in the browser. Video games with mod support are another example of hooks in action.",
"It is a general and quite broad term for giving access to and the ability to react to data being sent between software components. For example, a browser might use a hook to make it easier for antivirus software to scan downloads. When it starts a download, it shouts \"Hey, anyone listening, I'm starting a download!\", and any program listening for that will be able to react and intervene. Some hooks are intentionally put there by the developers. Others are clever tricks with existing functionality never meant to be a hook."
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799wiy | how does cryptographic salt and pepper work? | Technology | explainlikeimfive | {
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"When encoding information: Salt is/are random string(s) of numbers used when storing information. If you want to save a password in a database, you can't use plaintext, so you encode it. The sequence the encoder used to base its encription can be called the salt. You can now store the encoded password with the salt. The only way to check if someone used the right password is to run what they entered through the encoder using the matching salt. If what the person entered matches what you stored, it's the right password. However, this method is risky, as anyone using exactly the same encoder can still check passwords if they have the matching salt. Pepper is related to salt. Using the same hypothetical encoder, pepper would be an action done consistently to every password before it goes through the encoding/salt steps (like adding \"s6hk4\" to the end). This adds an extra variable to be accounted for when checking passwords. With pepper, in theory, even if you have access to the same encoder, the correct stored(encrypted) password, and salt, you still would need to guess the pepper, which is stored in a different location. [phone spelling]"
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79d4jy | Why does multiple Bluetooth connections cause music quality to degrade? | Anytime when listening to music, if there's more then just my stereo connected to my phone, the music will have a slight static to it. Disconnect all devices from my phone but the stereo, restart the stereo, and music is crystal clear again. | Technology | explainlikeimfive | {
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"Modern BlueTooth devices support at least two simultaneous connections. The internal circuitry of your BlueTooth device needs to manage both at the same time. Some devices are better at this than others. It has nothing to do with \"two different signals in the same space.\" The BlueTooth protocol is designed, like WiFi, to peaceably coexist with many other devices broadcasting on the same frequency. There's no \"fighting\" going on over the air, but there is contention inside your BlueTooth device as it tries to manage two streams. Some devices mitigate this by only allowing one media stream and one phone headset stream at the same time. I have multiple BlueTooth devices and I've observed my phone allocate one for \"media audio and phone calls\" and the other for just \"media audio.\""
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79e4gr | Trackless train. How does that work and compelling benefits of the same? | Technology | explainlikeimfive | {
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"text": [
"What do you mean by \"trackless\"? You could mean: * Not needing tracks like an Australian road train vs a CN train. * Not having a dedicated guideway like an articulated bus vs a subway train. or maybe you mean something else?"
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79eodc | How do bluetooth headphones work? | Technology | explainlikeimfive | {
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"They work like regular headphones except instead of getting the audio data over a wire they get it through short range radio transmissions. Headphones are basically tiny speakers you put in your ears. Speakers are diaphragms which move air in order to make vibrations, which are sounds. Basically all speakers these days are operated with electricity which makes an electromagnet tug or push on a magnet attached to the diaphragm. The instructions on how to move the diaphragm are either sent over a wire or in the case of wireless headphones through radio transmissions."
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79g446 | the difference between an i3 and an i7 processor (physical) | Technology | explainlikeimfive | {
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"Yer not alone in askin', and kind strangers have explained: 1. [ELI5:What is the difference between core i3, i5, i7? ]( URL_2 ) 1. [What's the difference between i3, i5, i7, and i9 CPUs? ]( URL_4 ) 1. [ELI5: What's the difference between the Intel I3, I5, and I7 processors? ]( URL_3 ) 1. [ELI5: What are the main differences between Intel's i3, i5 and i7 processors? ]( URL_0 ) 1. [ELI5: What is the difference between and i5 and an i7 CPU? ]( URL_1 ) 1. [ELI5: i7 chip vs. i5 chip]( URL_5 )",
"A [die image will probably help]( URL_0 ) CPUs are made up of many similar and repeated blocks. The biggest difference between an i7 and an i3 from a spec point of view is the move from 4 cores to 2 and a reduction of cache. These are still hyperthreaded cores and still give the same performance as the cores in an i7 so they are likely the absolute same core. In the image above you can see the die of a 7th generation i7 processor. Its got an IO control up top, 4 cores down the sides, L3 cache running down the middle, IO interface on the right side, and the GPU in the bottom. An i3 will look nearly identical except two of the cores will be gone and the cache will be smaller. Consider the image with just one CPU core on each side, a half sized cache, and everything squished in to this new area All of the supporting systems like the IO control, IO interface, and graphics will remain unchanged except in models with different GPUs but they just drop it into the same block.",
"If you were to open one up, you'd probably be surprised that there isn't much of a difference, if any at all. So what gives? Is Intel nerfing some CPUs so they can charge more for them? Not exactly. Chipmakers practice a technique called \"binning\". You see, we've gotten pretty good at making tiny CPUs. We're just not good at making every one of them perfect, which is a tall order when you're dealing with parts smaller than a virus. So as each CPU die comes off the line, it's tested and sorted into bins depending on its performance. The Core i7 are basically perfect off the line, with no major flaws. Some may take higher clock speeds than others, but that's really all that differentiates them. Core i3 chips are basically i7s with a couple bad processing cores. Since these cores don't behave correctly, or just don't work at all, they're disabled. Since a smaller percentage of chips that meet i7 grade come off the line than i3, they command a higher price. Regarding the i5, they're basically i7s with a few minor flaws that prevent certain features like Hyperthreading from working. Pentium and Celeron chips are i5s with a couple bad cores. AMD does the same thing with their CPUs, but they don't have an equivalent i5 bin for slightly flawed chips, so they just disable them. Which means in some rare cases it's possible to re-enable those slightly flawed cores through some computer voodoo. It's what PC hobbyists have coined as the \"silicon lottery\". Cheaper chips that can perform or clock higher than expected."
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79i4b5 | how does recycling work | What do companies do with recycled materials, and how are they reused? | Technology | explainlikeimfive | {
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"There are many different ways that companies use recycling in daily operations. Paper Paper is very often recycled by means of mashing it into a pulp like consistency and reforming more paper. This can be used in anything from grocery bags to pages in a book. & nbsp; Glass Similarly to paper glass is sorted by clear, color, and brown varieties which are ground down to very small particles which are then melted to form new glass containers and bottles. Some companies (especially milk suppliers) reuse their glass bottles by extensively cleaning them and then bringing them back into circulation. & nbsp; Plastic Plastics are one of the largest parts of recycling centers and one of the largest pollutants of landfills. Much like glass plastic is sorted by color and then melted and made into another form, sometimes it's bottles or containers. Now they are making clothing, insulation, building materials, and much more. & nbsp; Metals The most common form is remade into sheets after removing all the paper labelling etc. From this form it can be molded into anything. & nbsp; You can see that recycling involves much of the same principles but the underlying goal is to reduce the need for \"new\" materials to be needed. This has thus far been a partial success eliminating a lot of waste from entering landfills, but there is a lot of room for improvement."
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79k3jx | How come our phone screens can make it harder to fall asleep if used before going to bed, yet it’s so easy to fall asleep when watching a film/tv | Technology | explainlikeimfive | {
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"The blue light in the phones screen is the same spectrum as sunlight. Sleep patterns work around sunlight, as you become tired as night falls. I've used apps to cut off the blue light at a specific time and the first night I knocked out at my laptop."
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79madw | What is the meaning of "1.4" in "1.4 Petrol Engine"? | Technology | explainlikeimfive | {
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"1.4 is the engine displacement. It's measured by the cylinder bore (width) and stroke (the difference in the farthest travel up and down in the cylinder). Grossly overgeneralizing, larger engine displacements will result in greater power production, while smaller naturally aspirated engines (not turbo or super charged) produce less. Can't speak for where you are located, but 1.4 L would be on the smaller end of engines here in the USA. Edit: a word",
"1.4 is the number of litres the cylinders have collectively, i.e. in a 4 piston 1.4 L engine each cylinder has a volume of 350 cc. How it relates to power is that the larger the volume/cylinders, the larger the explosion in each cylinder so the more force generated in the engine.",
"Nowadays, it's mostly marketing, but their meaning used to show engine displacement (i.e. swept volume of all the pistons inside the cylinders of a reciprocating engine in a single movement from top dead centre (TDC) to bottom dead centre (BDC)), specified in liters. So 1.4 means the volume of the piston chamber that is where the explosion happens as the pistons move down is a total of 1400 cubic centimetres. However, these figures are usually rounded up, for multiple reasons, so you can have a 1211 cm^3 engine that is labeled as 1.3. Historically, displacement meant more power, since there was more room for the explosion, thus a more powerful explosion could happen. Furthermore, displacement is far less important in modern engines that make a lot of power from less displacement, with significant fuel savings."
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79nw9k | ... What is Kinematics | For my college work. I'm studying game engines and we have no idea what it is. Thanks. | Technology | explainlikeimfive | {
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"Mechanical engineer graduate here. Kinematics is the study of the motion of that object through space due to it's geometry, not forces applied to it. If you're designing something, especially something that has movement, many times the priority of your design isn't whether it can handle the loads applied to it, but how it moves. A great example is the [4 bar linkage]( URL_0 ) that's used everywhere. If you're designing an adjustable light stand, or a car trunk opening, you already know the linkage won't experience high load, so you can de-emphasize it in your design while you prioritize it's motion. You want the trunk to open a certain way. Gears and cams also fall under kinematics.",
"Coming at this as a (very) amateur animator, which might be relevant if you're approaching from a game engine pov, kinematics get divided into forward and inverse. Forward kinematics would involve posing the shoulder of a character, then the elbow, then the wrist to get the hand where you want it. Inverse kinematics involves setting up rules and relationships between the bones so you can move and rotate the hand where you want it while the rules handle the bones between the hand and the body.",
"It's the study of movement due to geometries, without taking into account things like forces or inertia. So if you have a hip joint and a knee joint, the knee moves in a spherical space around the hip's ball and socket joint, but the knee can only move as a simple hinge, opening and closing in its plane with less than 180 degree motion. So it only consists of the geometry and the geometric constraints imparted by the geometry of the design. Once you get into things of how fast they can go through the motion and the forces and inertias, you are veering off into kinetics."
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79pcb5 | Anti-tamper software how it works? | Any IT here? Im curious about how an anti-tamper software works. | Technology | explainlikeimfive | {
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"Software engineer here. Let's change 'anti-tampering' to 'anti-debugging' or 'anti-reverse engineering'. Let's break this down into two different categories - In-memory (while the software is running) - On-disk (while the software is not running) While it is important to understand attack methodologies- I'll skip over that. Understanding attack methodologies is important in this scenario because this can shine a light on the internal mechanisms of software engineering / Operating system internals. I'll try to explain like you're 5 ;) In Memory: While a program is running it is possible to 'attach' yourself to its processes or threads (threads meaning it is multi-tasking). This is used for debugging software for legitimate means. It can also be used maliciously - sort of like a gun, to protect or to harm - so some software products attempt to throw off debuggers. There are a couple of ways to do it and they usually revolve around either anti-virtualization technology (is it running in Virtual Box?) or debugger detection. There can be some strange things regarding this too. In Windows for example you cannot attach a debugger to a process that is already being debugged. The idea then is to make your program _debug_ _itself_. This sounds strange I'm sure, but it is a totally legitimate way to do it. You do not actually have to make a complete debugger, but convince the Operating System you're debugging yourself. Other additional methods and techniques vary, the oldest in the book is (on Windows, once again) debuggers are supposed to set a certain _flag_ on processes when they're debugged. The idea is if the flag is set to TRUE then it is being debugged and the program should halt execution. The problem is though a lot of debuggers do not do this. As a final note, another technique is purposely throwing _exceptions_. Debuggers will stop debugging if an exception is thrown (the debugger interprets this as the software application crashing). The trick here is you create a custom _exception_ rule internally and do 0 divided by 0 (0 / 0). This will throw a zero divided by zero exception and execution will halt on the debugger. However, your application will know what to do on this exception and continue as it normally would while the debugger is in a _frozen_ state. To be fair- all of the techniques described above have ways to avoid this. The solution to resolving things like this go to on-disk modifications e.g. changing the code! This is where on-disk anti-reverse engineering techniques come into play. On Disk: If your program is not running it has no way to defend itself. End of conversation. You can do a few things: digital signature / hashing, string obfuscation, variable/function obfuscation, instruction obfuscation (packing), or 'stubs'. Most products will use the first technique described (signatures) while more sophisticated software products will use a combination of the techniques listed (anti-viruses for example). The idea behind a signature is that your software and all of its instructions in totality create... well... a unique signature! If / when your program is launched and it appears the signature does not match, guess what? It's been modified. Halt execution. It's as simple as that. Now, the other techniques described though go a bit further and go on so that not only can someone not modify it but then _they_ _cannot_ _see_ _how_ _it_ _works_. This is pretty simple in theory. A string is a combination of letters. WCHAR StringExample[ ] = L\"THIS IS AN EXAMPLE OF A STRING\"; Okay, on disk someone trying to tamper with the software can see our example of a string as plain as day. The idea is that the string is encrypted and when the string is needed it decrypts itself. Makes sense, right? Function/Variable obfuscation is similar. The names of the functions and variables (a variable being WCHAR StringExample) would be changed so they appear like WCHAR Fgv561[ ] = L\"THIS IS AN EXAMPLE OF A STRING\"; Now, the person trying to reverse engineer the software has no idea what the variable is going to be used for. The name gives no context clues. The final two techniques are a bit more sophisticated and I'm at work right now. I'll finish this later."
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79pouf | Why are there so many different shapes of water towers? | Technology | explainlikeimfive | {
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"Not exactly an answer but remember that water towers do not supply water: they supply water pressure to the whole system. The key design feature is that the water has high potential energy to drive it through the whole system. [Like this]( URL_0 )",
"Water towers can vary in size quite a bit. What is most cost effective for a 25,000 gal. tank is probably not the most cost effective for a 3,000,000 gal. tank. Also the tank owners may have specific desires for the tank. Some tanks with larger towers can use that space for storage, etc. By the way, the lollipop shaped towers are probably pedesphere tanks and the ones with lots of supports are generically known as multi leg tanks, I believe.",
"They have varying needs for height (pressure) and volume, must meet local zoning regulations for appearance and strength, and must be engineered to work with local soil strength. Municipal water systems may emphasize beauty over cost as a matter of civic pride. If one is going to paint the town's or the high school football team's name, one might prefer sleek and swoopy lines to the basic tank-on-legs style that looks like a decaying relic from War of the Worlds."
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79ugrp | Why do so few smartphone companies use stock Android? | Technology | explainlikeimfive | {
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"Custom UI means the users get used to that one experience. Companies hope that users will keep buying their products for that experience (e.g. what Samsung is doing with TouchWiz). Differences are mostly selection of default apps (branded apps by phone manufacturer) and UI when we are talking about traditional phone companies like Samsung, HTC, LG etc. OnePlus for example changes a lot more 'under-the-hood'.",
"In addition to the main answer (driving customer loyalty through familiarity and/or unique features), there is another factor at the bottom end of the market. Some companies will pre-load malware for money. This is more prevalent in the PC market (where pretty much every big manufacturer takes money from McAfee to preload a 'free trial subscription' of that program), but it exists in the mobile market too. I've purchased a bottom-of-the-line tablet that came with preloaded adware that required root access to remove. It was pretty unobtrusive adware, showing up infrequent ads but it was there.",
"Let's be honest, stock android is cool but it doesn't have all the necessary features. It took ages to implement split screen functionality. While Samsung user had it for a long time. Basically, manufacturers try to attract user with unique features that are not available on stock android. Most of the times, these features are mere gimmicks, but every once in a while they tend to be useful. So much so that people might pick a based on that feature. And to be honest, most of these custom ROMs don't remove any stock features. Stock android is generally smoother and performs a little better than custom ROMs but today, even entry level phones have processors good enough to run the phone almost lag free. So having custom features doesn't hinder performance as much and you get extra features to boot. I personally use a Xiaomi Redmi Note 4. Which comes with MIUI as stock. On all my previous phones I've used custom stock baser ROMs like Cyanogenmod and enjoyed them. But ever since I got my Redmi I tried using custom ROMs but the battery and performance of MIUI is so smooth, it really is no issue in terms of usability. I honestly think it's better than stock ROM. This is mostly a case of optimisation by Xiaomi which is better than what some random users can build on XDA, but still, my personal experience tell me the stock ROM is better. Basically It depends on the user rather than any objective differences"
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79wcvd | - How do baggage scanners at the airport work? What do the different colors on the x-ray mean? | The x-ray I get from my doctor is only black and white whereas the x-ray scanners at the airport show different colors. Also, what do the colors mean? | Technology | explainlikeimfive | {
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"The x-ray devices in luggage scanners are a bit more complicated than the x-ray medical imaging devices. In particular, they're set up to identify and distinguish between different *kinds* of objects, whereas medical x-rays are pretty much only interested in one: bones. The trick is that not all x-rays are created equal. The x-ray source will send out x-rays in a *range* of energy levels. Organic objects block low-energy x-rays some, but not higher-energy x-rays. Plastics block low-energy x-rays better than organic objects, but not as effectively as metal objects, which pretty much block everything. The device is set up so that the x-rays pass through your luggage and then hit the first detector, which sends an image to the computer. But the x-rays then pass through a filter that blocks out all low-energy x-rays before hitting a *second* detector. That sends another image to the computer, this time only showing those objects that block high-energy x-rays. By combining these two images, the software can distinguish between organics, inorganics (e.g., plastics), and metals. It then assigns different colors to each. I think most manufacturers use black for metal and orange for organics, but I'm not sure about that. Could vary from machine to machine.",
"The main idea behind baggage x-rays is that a bag has to be scanned thoroughly in a short period of time, and that different items are to be scanned. To help with that, they use colours since we are more prone to notice colour difference. The colours vary with density- increasing tends to blue so the dense metals and alloys are shades of blue (think laptops, guns, mallets). Decreasing density tends to red, so the redder it is means the item is lighter like a thin fabric or just a linen sheet. Green is always plastic, so they tend to look for laptops and parts with the green colour. A particular example is green rectangle with blue screws, that'd be a laptop. Hope this helps!"
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79y4cg | How do scientists decide where to point the Hubble or Kepler telescope? | How do we know where to point it, what to look at? | Technology | explainlikeimfive | {
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"Typically researchers will submit proposals for telescope time slots to a committee which will review the requests to determine if they are worthwhile, ranking them by priority and feasibility. Included in the proposals is precisely the kinds of observations requested so if the telescope is going to be positioned in such a way as to make such observations convenient then it is more likely to be fulfilled sooner."
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79ynd0 | Why do we need thousands of nuclear weapons when one is enough to destroy any target? | Technology | explainlikeimfive | {
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"A 100 would not be enough to end the world. You could probably destroy all the infrastructure in a large country but definitely not the whole world. The whole purpose of having a ton of nukes is so that you always have more nukes after the first bombs have fallen. If a country only had a handful of nukes then a preemptive attack can destroy them before they launch and the country has no recourse. We currently have more than enough nukes that an enemy country could never destroy them all. There would be nuclear retaliation, and any plan where the enemy can nuke you back is a bad plan."
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7a00jp | What is Anti-aliasing, what's the difference between the kinds, and why does it help in gaming? | Technology | explainlikeimfive | {
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"Here's a close-up of what is generally meant by anti aliasing. URL_2 Basically, it can be thought of as smoothening the edges of an object to make it look more natural from afar. Here's another example that I screen shotted from [this]( URL_0 ) wikipedia article on spacial anti-aliasing (MSAA, or multi spacial anti-aliasing, one of the methods that you've probably seen in the menus if you've played a PC game). URL_1 There are dozens of different methods of doing this in 2D art, and then even more came about when 3D media started being made. There are various algorithms and techniques that anti-alias in different ways. Some are meant to focus on different parts of a scene, like the background, foreground, the edges of an object. A lot of these methods are derived from methods used in graphic design/early web design to make fonts look smoother. Most have jargony and intimidating names, some are based on the person who came up with the method. Some methods of anti-aliasing are proprietary, like nVidia's TXAA which was designed by and for nVidia. All in all, the different names just refer to different methods, techniques, or algorithms to smooth pixels and make things look nice without sacrificing performance.",
"Basically anti-aliasing prevents jagged edges on walls and stuff. Example: URL_0 You can see the towers edges are all blocky vs the smooth surface of the aliased one. It makes an incredible improvement in games at the cost of performance which is why consoles typically don't use aa."
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7a2iel | Snapchat can do filters on any smartphone with a front-facing camera, so what's different with the iPhone X's new facial recognition tech? | Technology | explainlikeimfive | {
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"Snapchat can recognise that there's *a* face in the image and where it is, and apply a filter over that face. The idea of Face ID is to recognise that *your* face is in the image, and use that as a trigger to unlock the phone."
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7a36jr | How is sound generated from music files? | From my understanding, human hearing is limited to 20-20,000Hz. If this is the case, how are songs different? Are different frequencies played at a very high rate of speed or are they combined somehow? | Technology | explainlikeimfive | {
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"Many sounds at once is not a problem at all. Sound is a wave and when you have multiple waves you can simply add them together to get the result. [Here is a gif example]( URL_3 ) where green and blue wave together form the red wave. The red wave alone is enough to perfectly describe how green ad blue wave act together. Sound is a simple wave. You can see the wave of a sound file with any sound editing program. [Audacity]( URL_0 ) is popular free one. [Here]( URL_1 ) is an example of the wave of a bass playing some notes alone. The selected area is three seconds long. Now how is this stored on the file? You simply store the value of the wave at certain sample points. With enough zooming in you can see them [here]( URL_2 ), each point is single data point. The data points are usually taken with sample rate of 44100 kHz so one sample every 0.022 ms. This is twice the frequency of human hearing and due to some math reasons you need twice the sample rate of your signal (sound). So you take the recorded wave and store the value of the wave very frequently. This would be a simple .waw file with no compression. Mp3 and others add compression and that complicates things.",
"They’re played over the top of one another. In all your daily life longitudinal sound waves are overlapping each other, and when they do they basically add to each other (if a compression of the wave crosses a rarefaction (low pressure) then they will cancel out, if two compression cross they will create a very strong compression at that point, etc) [like this]( URL_0 ) . With lots of different frequencies doing this all at once the wave forms become pretty weird in shape. You microphone then takes all these weird patterns and turns them into and electrical signal. The opposite then happens when they’re played: your file is played as a mix of all the waves added together. Soz pretty bad explanation but happy to answer further."
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7a3ah2 | How does video and image stabilization technology work in our smartphones on such a small scale? | Technology | explainlikeimfive | {
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"Two kinds of image stabilization systems exist: mechanical and digital. The mechanical systems use small accelerometers built into the chips of the camera to notice movement in the camera during the time the camera is taking the picture and make small opposite movements in the CCD sensor so that the sensor and lens remain focused on the same point. As the picture usually takes less than 120th of a second for mechanically stabilized pictures, it only needs to move the sensor a few tenths of a millimeter in most cases. Digital stabilization works by taking more than one picture in quick succession, finding common points within the successive images, determining how much they have moved and reversing that movement digitally, so in the output file they don't appear to have moved."
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7a4fn9 | What's the deal with cellphone store operators? | Technology | explainlikeimfive | {
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"text": [
"They’re authorized retailers. They have access to the wireless providers database and can setup new accounts and handle issues. The wireless provider wants a physical presence but doesn’t want to incur the cost of hiring staff, renting a physical location, etc. so they basically outsource this to someone else and then won’t have to deal with the extra expenses. In return the authorized retailer gets some cut, depending on their contract."
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7a5vtu | How does a computer read a CD or DVD and extract the appropriate content? | Technology | explainlikeimfive | {
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"The disc is spun and below it is a laser mounted on a track that moves back and forth so it can be pointed at any point on the disc as it passes over. When the laser hits the disc the light is reflected back and there is a sensor ready to detect it. However by altering the disc, either by changing the distance between the laser and the disc surface (by making a small pit in the disc) or by using special dye you can make it so that some points on the disc don't reflect the laser into that sensor. So as the disc spins the laser is essentially reading points on the disc as either \"reflects light\" or \"doesn't reflect light\", 1s and 0s to a computer which can be used to represent any computer data including audio or video. The actual patterns of 1s and 0s are slightly different then what a computer uses. This is because a series of all 1s or all 0s would be difficult to read - there needs to be a break to help keep the timing in check. So instead a larger sequence of bits (that have limits on repeats) are used to represent a smaller one - for example 10 bits on the CD might translate into 8 bits for the computer. Discs can have multiple layers (CDs have only 1 layer, the surface of the disc, DVDs can have 2, Blu-ray discs can have more) which is accomplished by making the outer layers transparent in some way - by altering the laser light you can choose which layer you are aiming the light at with the laser passing through any other layers in the way."
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7a8fka | How do noise reduction headphones work? | Technology | explainlikeimfive | {
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"text": [
"They use a microphone to capture outside noise then generate the opposite waveform to cancel it out when they meet."
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7a9pr1 | Why are video game graphics just now becoming so detailed and in depth? 10 years ago, you couldnt see reflections or walk up stairs properly, but now you can? What has happened to code writing that's allowed this? | Technology | explainlikeimfive | {
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"text": [
"It’s not code really. It’s waaaay more powerful processing being widely available. Both CPUs and GPUs. All of those details take a ton of processing power to do, processing power that 10 years ago wasn’t so readily available.",
"In some cases it can be coding, with programmers learning to do new things, but the big thing would be processing power. 10 years ago, the average consumer computer was much weaker than it is today. The computers could only do so much at once, while maintaining a reasonable framerate to make the game playable. A really good example is the movie Toy Story. Looking back at it, by today's standards, it is pretty basic, but at the time in 1995, it was cutting edge. To add to how hard it was to make, each **frame** took 45 minutes to **30 hours** to render. And this was done at 24 fps at 1536x922 resolution. And even then, it took about 300 processors to render all of that. At the time, that was pretty impressive for a film that could probably be rendered in real time with a modern day machine.",
"Computers got more powerful. It isn't the code. We take for granted the sheer amount of computation needed to render stuff in games. Just take a look around you in the room you are in, you are probably in the presence of a light bulb or the sun. This is a bit more fun to think about with a light bulb, but just take a look around you, at all the shadows, how everything is lit up, the reflections, ect. Light radiates out predictably in a straight line and this makes our calculations possible. The computer has to calculate all that, it has to calculate if there is line of sight between an object and a light source to see if a shadow is applied to behind it, it has to calculate how that shadow will look like based on blocking it. You can do all this by hand theoretically, it is just algebra and trigonometry, but you would likely die before you finished all the calculations needed just for one second. Colors as a result of lighting as well, and even the player's line of sight has to be calculated. And it is all done at the very least 30 times per second. All done on a rock that we tricked into doing calculations."
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7aa45g | what is a strong and weak type of language in programming? | What does this mean? What are the advantages and disadvantages? | Technology | explainlikeimfive | {
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"It simply has to do with strictness. A strong typed language requires precise declarations where as a weak typed language does not. In PHP for example $ represents a variable and it can be any type. We can assign $myname = \"me\" or $myage = 20 and PHP automatically recognizes that one is a string and the other is an integer. But in Visual Basic we need to define the variable type before we can assign a value so, dim myname as String and dim myage as Integer, then we can assign the values myname = \"me\" and myage = 20. Thus, PHP is weak typed and Visual Basic is strong typed. This strong and weak paradigm extends to all assignments including how values are passed to and returned from functions and objects. Some languages incorporate levels of strength and can be useful to require explicit declarations to intentionally produce more or fewer errors."
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7adjo4 | How is a satellite able to transmit so many channels in HD/SD to so many TV dishes across the globe at once? | Technology | explainlikeimfive | {
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"It doesn't have to transmit to each dish. It transmits each channel a single time, and then as many dishes as there are can listen. It's the same for radio or other broadcasting technologies. This is opposed to streaming, with say Netflix, where Netflix servers need to send continual two way traffic between their servers and each user for a personal stream. A satallite could definitely not handle with traffic to the user base of satallite TV. As an analogy, satallite TV is a guy with a megaphone communicating a message to a crowd of 1000 people. Netflix is 1000 messnager carrying out a conversation with 1000 people to convey the same message.",
"The number of dishes receiving it doesn't matter. Satellite TV is a broadcast system, it just sends the signal out for anyone with the right equipment to receive. It's not like the Internet where it has to send a separate copy of the data to each user."
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7af9dw | How did old guitar effect pedals actually produce effects such as reverb & delay? | Technology | explainlikeimfive | {
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"I'm not too sure about delay, though there were some 'tape delay' units that worked like cassette tapes, except the tape was in a small loop. It had both a record head and read head running on one tape, so it would record the input from the guitar and play it back after a short delay. You could adjust the delay by adjusting the tape speed. In theory you could adjust the delay by changing the distance between the heads also, but I'm not sure if this was done as it would be more complicated. For reverb the old school way (might have been others) was called spring reverb. They stretch a string between two moving coils, which work similar to how a speaker and microphone work (electrodynamic speaker and mic, anyway). One end of the spring is vibrated by applying the input signal to the coil, making it move like a speaker. The waves would run down the spring and go back and forth, and interact, kind of like how sound waves would bounce around a room and interact, and reverberate! At the other end of the spring, that coil would be used as a microphone to pick up the sound and add it back to the signal that's being fed to the amplifier."
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7ago0h | How does a magnetic strip (such as on a credit card) store information? | Similarly, is a full swipe of the strip through a reader needed to process the data it holds or does only a portion of it need to be swiped? | Technology | explainlikeimfive | {
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"You know how magnets have a north pole and a south pole? The mag stripes are made up of small magnetic particles. By applying a strong magnetic field, you can orient the magnetic direction of those particles one way or the other. The particles themselves don't move, just the direction that they are magnetized. When you move the stripe through a reader, the changes in magnetic direction [induce small pulses of electrical current]( URL_0 ) in the reader, which are then amplified and turned into digital data. A stripe can contain redundant data, so you may only need part of the stripe to be read. It depends on the card. There are commonly 3 \"tracks\" on a stripe, where a track is a lengthwise section of the strip. Each of those tracks is used for slightly different things, but 1 and 2 quite often contain the same data. So even if one is unreadable, the other one might be OK. Usually the critical information (such as a credit card number) doesn't go the entire stripe length. So a partial swipe could work."
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7agpix | Why do lightbulbs go out, but not the lights that illuminate screens on TVs and phones? | Is it even possible for them to go out? | Technology | explainlikeimfive | {
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"it is, DLP tvs for example used a honest bulb (though very bright and powerful), and it had a life of a few years. LCD screens use edge lighting, most are LEDs these days (all cell phones), but they used to use compact florescent lights (rarely still do). both have absurdly long lifespans, longer than the devices they are in. but its possible for the backlight to fail. the newest phones (and some TVs) are OLED, which means the screen itself are itsy bitsy LEDs that generate the light themselves. again, super long life.",
"Really the more interesting question is **why do lightbulbs go out** rather than why the light sources in screens don't. Afterall, the lightbulbs 100+ years ago had the same lifespan as modern ones -- why hasn't the material science made any progress there? The answer is that lightbulbs are one of the first, and most egregious case of planned obsolescence. They are *designed* to go out, because if they lasted forever, there would be little demand for new lightbulbs. From 1920s to 1940s the lightbulb makers formed the [Phoebus cartel]( URL_0 ) which explicitly ensured that no manufacturer sold lightbulbs with more than 1000 hour average lifespan. The cartel has gone, but the practice still continues.",
"They most definitely go out. On LCD TV's and less than flagship phones it's called a cold cathode backlight. And it's a physical part, which can fail."
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7aj959 | Why are video games almost always rated between 6-10/10 with 6 being considered a terrible game but movies and tv shows seem to be rated between 1-10/10 with 6 being decent. | Technology | explainlikeimfive | {
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"Game journalism is very different compared to movie reviews. Most game journalists will not even finish a game before putting out initial impression reviews. Movies are only 1-3 hours long. Many games can be 60+ hours and the competition to get your review out as soon as possible is real. Like you see with the movie industry with many critics, the companies who produce the content have relationships and deals with the game reviewers. Big developers often give their reviewers perks like advance copies of big titles. Reviewers want to maintain their good relationship to keep getting these perks, and AAA publishers know that 1 bad review could seriously harm their multimillion dollar investment into a product. Part of it is probably just a different culture. That's what reviewers are used to doing and used to seeing, as lame of an excuse as that is. I also personally believe most people don't really know what goes into making a game good in terms of level design, music, pacing, animation, level of polish in all those details, ect. so it's difficult for many people to be displeased with a game when they don't really know what makes a game good or bad. Also, anchoring.",
"Because a lot of education systems see 70% as a bare passing grade. So people grow up with that mindset. You see a 5/10 game and think \"oh that must be horrible\", even though that should be just average. That's one thing I like about Destructoid and Jim Sterling's review scale, it actually reviews games out of ten. A 7 is still a good score BotW fans.",
"The ratings mean the same thing: roughly, \"watcheable\" or \"playable.\" The difference is watcheable means you spend 30 minutes to 2 hours of your life getting an average experience while playeable means you spend 30 to sixty hours getting an average experience. Is not that the ratings mean different things, its that your time has value and if someone offered you 30 hours of an okay experience, you'd probably take a hard pass.",
"Also to consider there are many more factors to include in a game’s review. You have graphics, frame rate, gameplay, controls, UI, replayability, difficulty, load times, multiplayer, balancing. On a tv show or a movie, there isn’t any of that stuff to consider. So if a game comes out with a great storyline and campaign, but the frame rate is lousy, controls are awkward and doesn’t give the gamer the ability to modify them, game is too easy, and offers nothing after beating it, that could bring it down to a 7 and with those negatives, could be considered bad. Also must consider the cost. A movie is $13-15 bucks and a couple of hours. If it sucks it’s not as big of a letdown if you dropped $60 and 25 hours into a game."
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7al6co | Noise Isolating headphones vs Noise Cancelling | I see lots of headphones that are Noise Cancelling or Noise Isolating. What's the difference and how do they work? | Technology | explainlikeimfive | {
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"noise isolating. consider this ear plugs that have earbuds in them. THey block outside noise by providing a noise reducing barrier. In fact my isolation earbuds are so good I use them as Earplugs when using a circular saw or mowing the lawn. NO music and not even plugged in. Noise Cancelling Headphones that essentially listen to ambient noise and produce an opposite sound wave to blank out the unwanted sound. Fill your bathtub with water. Drop two rocks into the tub one at each end. When the waves collide you will see a spot where the water seems calm because the waves are cancelling each other out. Noise cancelling headphones produce this negative wave by listening in to the outside noise and producing the opposite wave to cancel out the wave just like in the water.",
"Noise isolating headphones block sound. Noise canceling headphones effectively add anti-sound. Anti-sound is identical to the original sound, just out of sync by half a wavelength. A sound is just a pattern of high and low pressure air waves. By adding another sound that has high pressure when the original one has low pressure and vice versa, you cancel out the sound. Noise canceling headphones generally require their own batteries in order to analyze sounds and make the corresponding anti-sounds. Noise isolating headphones just need to cover your ear with something that doesn't transmit sound very well.",
"Noise isolating is like using insulation to keep your house warm. Noise canceling is like adding a heat source to the house.",
"ELI5: can noise cancelling headphones mess with my hearing? I mean, that signal being pushed into my ears over time. Especially as someone who suffers from tinnitus.",
"Imagine you're standing on the long rope bridge at the playground and Jimmy is on one side of the bridge shaking it up and down. When he shakes the bridge like that, you move up and down, and that's kind of how sound works. For a noise isolating headphone, imagine that we lay down a bunch of heavy blankets all along the bridge to weigh it down. Jimmy's still shaking the bridge up and down just as much as before, but you don't move around quite as much. That's like how a noise isolating headphone tries to quiet down the sound waves that are coming to your ear. For a noise cancelling headphone, imagine that I'm standing on the ground in between you and Jimmy. While he's shaking the bridge, every time he lifts the bridge I pull down on it, and every time he pushes down on the bridge I lift up on it. The better I'm able to perfectly counteract Jimmy's shaking, the more it's like you don't feel any shaking at all. That's like how a noise cancelling headphone tries to cancel out the sound waves that are coming to your ear. Please don't hang out with Jimmy at recess anymore.",
"\"Noise isolating\" headphones are like earplugs with headphones in front. The sound outside your ears hits the earplugs first, which makes it quieter. Since the headphones are on the ear side of the earplugs, they don't have to be as noisy for you to hear them over the noise the earplugs are blocking. \"Noise cancelling\" headphones use a neat trick to make sound \"disappear\". For every sound, there's an \"opposite\" sound. If both sounds happen at the same time, you \"hear\" no sound. So \"noise cancelling\" headphones have a microphone and a computer. They constantly and quickly sample the noise around you, create the \"opposite\" noise, then add that noise to the music you're hearing. To your brain, this sounds like \"I am in a quiet room and this music is playing\". Because of this, \"noise cancelling\" headphones need batteries even if they have a wire, because the computer and the microphone need a little bit of power to work. They tend to be fairly big and bulky if they work well. Since \"noise isolating\" headphones are just earplugs, they can be smaller and don't need batteries to work. Unless they're wireless, but that's unrelated.",
"Lots of good explanations here. I'll just add more info as a headphone collector. Noise cancelling (also known as ANC/active noise cancelling) headphones generally sound worse because of the \"anti-sound\" that they make. They also produce nauseating sensation that can make you feel fatigued. If you don't need to deal with constant and regular noise (e.g. engine noise), avoid ANC headphones.",
"Noise isolation is just insulation. Noise cancelling uses a tiny microphone to \"listen\" to the incoming ambient noises and cancel them out with destructive wave interference before they reach your ear.",
"The noise isolation ones are passive, like the ones you find on construction zone. They isolate you from the environment by blocking the exterior sound from reaching your ear. The noise cancellation one are active. They usually have one or several microphones to listen for the exterior sounds and cancel them by sending the same sound \"reversed\". Imagine you meet your boss and shake hands. You are both sounds and the eardrum is your handshake. You want to have a firm handshake (no noise or no movement of the eardrum). To do that you need to kinda apply the reversed hand movement of your boss. In this way, you will both move your arms but the handshake will have a fixed position."
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7aoc1x | How does a loading bar work? | When a game or a video is loading up, most of the times we can see a bar being filled until it is completely full. How does it work? I mean, is it just an "image" being multiplied several times? (Obviously I know there's a bunch of codes behind it) | Technology | explainlikeimfive | {
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"It can be done in many ways. Having multiple whole images of of the loading bar at various percentages is common. But just as common is generating it programmatically - describing it, not as whole lot of pixels, but as a drawing - a rectangle with rounded corners, and a thick line with sharp corners for the progress bar. Another way is having two images or animations, one of the full progress bar, one of the empty, layering the full one over the empty one, and only revealing the leftmost part of the full one, progressively revealing more of it as time progresses. More interesting is the logic for guessing how far through a procedure you are. Parts of the process will go faster than others, and some of it will be unpredictable. For instance, when Windows copies files, it only knows the number of files it has. If the first files were large, it will predict that this will take days, until it hits the lots of short files at the end and if finishes quickly. Now, you can fix this by checking the sizes of all those files when you start, but that takes lots of time. So you have to trade off better accuracy in your estimate against time taken."
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7aq4sx | CPU Overclock | I have just bought a new laptop. The Dell Inspiron 7577 i7-7700 3,8 Ghz laptop. however when I looked at the specs I only had 2,8Ghz. When I looked further I saw that it was 3,8Ghz overclocked. But I have no idea what I mean. I searched google and they say it is maxing out the potention of the pc. But never do they say how, or they give a professional 4 page essay. Thats why I thought I would ask reddit. | Technology | explainlikeimfive | {
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"It's probably an automatic overclocking for when the computer is subject to heavy operation. If you play a demanding game, the computer can \"put the pedal to the metal\" for you to make the game run smoother. This will however require more power which drains the battery faster and makes more heat. Computers will even clock down if you're not running any demanding applications as a power saving feature. BIOS overclocking is however rather unusual on consumer laptops due to the cooling systems having to trade efficiency for weight and laptop makers liking to squeeze your wallet for a tiny bit more speed. As for an ELI5 on overclocking itself: The \"clock\" on the processor is a bit like a metronome. It ticks at a certain beat, supervising the rhythm of which the processor works at. Overclocking essentially means ramping up the \"beats per minute\" of the processor.",
"Overclocking is the purposeful setting of hardware registers to operate beyond manufacturers recommended or \"stock\" settings. Results vary extremely wide based on a dozen or so factors, half of which are environmental. In the case of your laptop, there is likely a \"turbo boost\" option in the bios to unlock that extra ghz. Laptops are generally poorly suited to overclocking as they lack good aftermarket cooling."
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7aqb4e | How fiber cabling is faster than standard cabling. | Technology | explainlikeimfive | {
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"Standard cable uses copper wiring to send electric pulses that send data from one place to another. It's fast, near instantaneous for simple signals like telephony and SD cable. Fiber-optic cable uses mirrored flexible tubes to divert pulses of light, instead of electrons. Using fiber-optic cable, you can send different frequencies of light at the same time, increasing the number of channels available and increasing the speed in which information is transferred. This results in higher quality video, more variety of cable channels, faster internet, and clearer calls.",
"Individual signals inside both fiber and electrical cables do travel at similar speeds. But you can send way more signals down a fiber cable at the same time as you can an electrical cable. Think of each cable as a multi-lane road. Electrical cable is like a 5-lane highway. Fiber cable is like a 200 lane highway. So cars on both highway travel at 65 mph, but on the fiber highway you can send way more cars. If you're trying to send a bunch of people from A to B, each car load of people will get there at the same speed, but you'll get everyone from A to B in less overall time on the fiber highway than you will on the electrical highway because you can send way more carloads at the same time."
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7as73h | How are racing games able to show the time with an accuracy of 1/1,000 of a second when they run at only 60 FPS? | Technology | explainlikeimfive | {
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"what's being displayed and what's being recorded are entirely separate. the game knows exactly when you crossed the line at 1/1000 second accuracy. but it only displays it at 1/60 accuracy. you'll never be able to tell the difference. it's like if you're recording something once every second, but you only give updates once a minute. that once a minute update is your fps.",
"It's true the game might calculate movement/physics more often than once per frame. But not all do, and it doesn't need to. Say you're moving fast enough to travel 20 feet before the next frame, and the finish line is 0.5 feet away. You'll cross it in 1/40 of a frame's time. The game doesn't need to calculate your position 40 times each frame to figure this out, it just needs to keep track of your position relative to the finish line, and do this math when you are about to cross it (or recently did cross it).",
"Well, I don't know how games actually do this, but I can tell you how to do this as simply as possible. First, games have two different rates you may be interested in. Tick rate, and frame rate. Frame rate tells how often you draw the current game state to be displayed. Tick rate tells you how often you update the game state. These don't necessarily have to have any connection between the two, but the simplest possible way to design a game would be to tie these together so each time you draw a frame, you first update the game state. Updating game state means things like, move car location based on its velocity. So lets assume game has this simple architecture where ticks and frames are tied so that you just update game state and then draw that game state, 60 times a second. Even then, you can have much higher precision for lap times! Simply, each tick, store the last position, or better, what distance away you are from the finish line. Then, each tick, check if car has passed finish line. Once it has, you know that actually the car probably passed it sometime between these ticks, and so, if you were 1m away from finish line earlier tick, and you're now 1cm away from finish line, you know you actually passed the finish line pretty darn close to this exact tick. However, if you were 1cm away from the finish line and now you're 1m away from finish line, having passed it, you know you would actually have reached the finish line almost exactly after the earlier tick. If before passing finish line you were 1m away and after passing you are 1m away, you would have passed the finish line halfway between these ticks. Game could also run at higher tick rate and only draw the game every once in a while."
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7ats0z | Why do combustion engine cars have gears and electric cars do not? | Technology | explainlikeimfive | {
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"In a short, simple version: Electric engines can produce all of their power from a standstill, just put a charge to the motor and off it goes. Combustion engines have a 'sweet spot' where they produce the most power. An RPM range where they are most efficient. They have to work harder to put a vehicle in motion from a stop. Each 'gear' is a different ratio, at the low end you have minimal top speed, and maximum torque. The balance of top end / low end power gradually shifts with each gear ratio, again in order to maximize the 'sweet spot' and not completely stall the engine out. EDIT: also, a combustion engine is always in motion at idle. It's completing cycles, spinning all the time. There has to be a system of moving parts to engage / disengage the drivetrain after the engine in order to put it to use. An electric engine does not require this, because it can be at a stop when at rest, or 'idle'.",
"Another reason is that because electric motors can provide full torque from the standstill, the forces can simply break a conventional gearbox. The first Tesla Roadster was first designed to come with simple 2-gear box, but the torque of the motor kept mangling it. A strong enough gearbox would have been unacceptably big and heavy."
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7aug3c | How do programmers for large software or AAA video games manage to create one unified, compatible whole when each programmer may code with different logic and work on different parts? | I've done some programming, minor stuff, but it's always been on my own. I have sort of my own "personality" when I code, so I may think in a different way than someone else. After all, in coding, there are multiple ways to achieve the same end result. Whenever I've looked at someone else's code, it's always taken me quite a while to understand their logic, since my natural logic may differ. When I think of large games like Assassin's Creed, or any video game, it just baffles me how the programmers are able to work together on it all. I understand that they all sort of have their individual "parts" they make, and the tasks are divided among the programmers, but all those individual parts need to connect back together to create one whole. To me, this seems extremely difficult because it's not one giant brain programming the game, it's a team of probably 100 brains with millions of lines of code. How is this managed? It seems like an incredibly tough task. Person A may program one part, Person B programs another part, but when they try to bring those parts together their logic is incompatible. Can anyone provide me insight on how huge teams of programmers are able to work together on insanely massive projects? Thanks! | Technology | explainlikeimfive | {
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"If there's 100 engineers on a project, it's going to be split into many modules, and each person (or a couple people) has responsibility for their own module. Of course, you can't program in a vacuum, you will interact with other people's sections. So like flyingjam says, you use a published API for your part, and that's how others call your code, and this needs to be well documented. Many companies also have coding standards, which describe how to name variables, how big a function can be, how complicated a single line of code can be, where to put the API description, etc. But yes, a bigger project can take longer to do than just simply multiplying the time it takes to do a small one by the difference in size with the bigger one. All that extra communication requires more testing and more meetings. And you occasionally still end up with something like that spacecraft that crashed into Mars because one group was using English units and another group was using metric.",
"Same away a hundred different factory workers can all wind up making the same car. You develop coding standards and create a lot of shared libraries that have a standardized interface. For example, most games rely a lot on random number generators. Instead of letting each problem reinvent it from scratch, and have some do a bad job, you would have one programmer create a random number generation library that everyone else uses. Since the interface to those libraries is standardized, the code can be changed without affect the people who use the library...you hope. Once you have these libraries built, programmers don't write code so much as they arrange calls to various libraries. > How is this managed? It seems like an incredibly tough task It is a tough task, perhaps the toughest in the coding process. That's why any large project is going to have a bunch of managers and architects dedicated organizing how this happens and make sure the coders adhere to their plans.",
"For one thing, you write in a way that easily composited and provide internal APIs. So programmer A is working on an internal clock for the game. He says that it will be a static class with the methods .deltaTime() (which returns the time between the last frame and the current in seconds in a 32 bit floating point) ...etc Programmer B doesn't need to know how the clock works, just that he can call .deltaTime() and get a 32 bit floating point value representing the difference in time. And remember that in multi-person projects (...and preferably in personal projects as well), people use proper version control (Git, mercurial, whatever). So, for example, in git, Programmer A would clone the master repository, create a branch to work on his clock, and when he finishes he can merge his changes into master.",
"To add to other answers, most AAA studios use their own proprietary engine which all staff are trained on, so they'll know what to call and where it'll be, as well as how to code their own sections so others can utilise their code. They also have constant meetings where they all discuss where they are, what needs doing and the best way to go about doing it. And don't forget, most programmers work in the same room, look at any decent programming studio and you'll notice it looks nothing like a typical \"cube farm\" and is quite open-plan, this is intentional to aid communication and freedom, so programmers can often talk to each other informally by simply popping their heads up, or taking 30 steps. (I did a uni placement at a game studio, won't go into detail for privacy reasons, it's a famous studio but not a Triple-A one)"
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7aujyc | Why do so many electronics tell you to charge for X amount of time before the first use? | Technology | explainlikeimfive | {
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7axkse | How does speaker phone calls avoid feedback? | Whether it's on our cell phones or at work - speaker phones, how do the calls work so well without feedback? I realize that the quality is lower when using the hands-free or speaker phone but I still don't understand how it works at all. | Technology | explainlikeimfive | {
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"Don't know about cell phones, but they probably do the same thing as a speaker phone. At least, one of them. Speaker phones are generally designed to try to physically isolate the speaker from the microphone. This minimizes how much the output is coupled back to the input through vibrations in the speakerphone itself. (This is obviously harder to do in a cell phone.) But that doesn't stop coupling through the air. The other thing a speaker phone does is to check for correlation between the speaker output and the microphone input. If it finds correlation, it subtracts the speaker output signal from the microphone input. Older/crappier speakerphones simply run in half-duplex mode...they don't allow output and input at the same time. That's not too common these days.",
"When the phone plays loud audio from the other side, it lowers microphone sensitivity in order to prevent it from being picked back up again. Sometimes it isn't enough and the other end still hears an echo of themselves."
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7axsfw | My ISP claims to provide 16mbps internet, then why does a 16mb file actually take 6-7 seconds to download rather than one second? | Technology | explainlikeimfive | {
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"text": [
"MB and Mb are off by a factor of 8 Capitalization is important here. Your ISP is proving 16 Mega*bit* per second internet, the file is 16 Mega*Bytes*. A byte is 8 bits so your actual downspeed is 2 MBps so the file should take 8 seconds"
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7ayc0v | What exactly is happening when an LCD TV breaks and those black lines appear? | My kids are 6 and 3. 3 chucked the remote at the TV yesterday and while it's still alive, it's got fat black lines running vertically from the point of impact. Note that the black area goes forms a vertical line going up from the spot, but the pixels below the spot still work. The lines going horizontally are thin and faint - the pixels seem to have shifted their color, but are still functional. 6 asked why that happens, and I realized I didn't have a good answer. | Technology | explainlikeimfive | {
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"An LCD works because of a few layers. There are more than I will mention and multiple types but I'll keep it basic to explain what is happening to your screen. Light shines from the back and goes through a polarizing filter. Then through a liquid crystal layer. Which lets the light pass or doesn't (it works along with the polarizing filters. That's a bit complex for here) If your screen is color it next goes through a color filter that is red green or blue based on what color that sub pixel is (each pixel has a red green and blue sub pixel that is turned on and off to make that pixel color). The light then goes through another polarizing filter and comes out as a picture on the screen. The pixels are addressed in a grid like battleship, so the physical damage can take out columns or rows leaving the streaks you see. Depending on the type of screen and exactly how it is damaged it can permanently turn on a whole row of red pixels or any color making a colored streak."
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7azlh2 | Why are some websites so difficult to click back out of? | For instance I'll do a Google search and then click on a link, then if I click back it just reloads the current screen, so then I'll have to do two simultaneous clicks to be able to get out. Then there's [This]( URL_0 ) website that I can't even click out of. | Technology | explainlikeimfive | {
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"Some sites redirect you: you land on one page, it redirects you to another. You go back one step and you land on the redirect page, which then redirects you again ...",
"You probably got redirected to that page via a chain of other pages. So when you click back, you just go back to the previous link in the chain, which then instantly redirects you back to the page you are trying to go back from.",
"It’s kinda like stepping into quicksand. The more you try to get back out the more you sink in. When I find myself in this situation, I click and hold the back button then a string of previous pages pops up. I carefully look and select one of the page I was on before the quicksand to back myself out into safety.",
"The web wasn't really designed for highly interactive applications. It was built with static pages in mind: a URL would correspond to a single page, and you navigate from one page to another. Modern apps need to jump through a lot of hoops to attain app-like functionality within a platform not designed for it. So one of the weirdnesses you encounter is pages using different URLs to point to different \"states\" on the same page. At this point, the \"back\"/\"forward\" model breaks down, and your browser no longer behaves like you'd expect."
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7azyua | How exactly do solar panels create energy? | How is the energy made usable by the sun? What are the processes that go into making usable power? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Solar panels. How do they work? ]( URL_3 ) 1. [ELI5: How do solar panels work]( URL_4 ) 1. [ELI5: How do solar panels work? ]( URL_7 ) 1. [ELI5: How do solar panels work? ]( URL_2 ) 1. [ELI5 how do solar panels work? ]( URL_1 ) 1. [ELI5: how_do_solar_panels_generate_electricity]( URL_6 ) 1. [ELI5: How do solar panels generate and store electricity? ]( URL_5 ) 1. [Eli5: how does solar power work? ]( URL_0 )"
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"https://www.reddit.com/r/explainlikeimfive/comments/2julyl/eli5_how_does_solar_power_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/60aqg9/eli5_how_do_solar_panels_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/6aaar7/eli5_how_do_solar_panels_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/5oah3o/eli5_solar_panels_how_do_they_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/1obefa/eli5_how_do_solar_panels_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/5vf80o/eli5_how_do_solar_panels_generate_and_store/",
"https://www.reddit.com/r/explainlikeimfive/comments/70xo6k/eli5_how_do_solar_panels_generate_electricity/",
"https://www.reddit.com/r/explainlikeimfive/comments/37e7xv/eli5_how_do_solar_panels_work/"
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7b15f8 | Why are plastic and aluminum often collected together for recycling but paper has to be separated? | Technology | explainlikeimfive | {
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"text": [
"Every recycling plant is going to have their own policies based on what separating machines they have available. Aluminium and plastic is easy to separate. The ELI5 version, is, aluminum is magnetic, so magnets can separate. To be a bit more precise, you would use eddy currents to separate aluminium from plastic. Your local recycling plant probably doesn't have a great way to separate plastic and paper, so they make you do it."
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7b2gia | why, in the days of dial-up internet, if someone picked up a phone on the same line it would drop the connection. | Technology | explainlikeimfive | {
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"text": [
"Data was being communicated via sound on the phone line. If someone picks up an extension, that adds noise via the microphone on that phone, and causes errors in data transmission. If there are too many errors, the connection is lost.",
"Dial up modems communicate by noises over the telephone, the beeps and buzzing noises. For two modems to stay in communication, they have to establish and maintain a connection. If it doesn’t, the models lose track of what they’re saying to each other, so to speak. Sort of the same way that if you and I were talking and other people were talking loudly around us, at some point we wouldn’t be able to hear each other over the other voices. We’re still making noises at each other but we’ve lost track of what we were saying and aren’t effectively communicating anymore. Lifting up the phone, even the ambient background noise and the click of the receiver being picked up is enough to break the connection, since the modems are relying on such subtle noises to talk.",
"Imagine you're playing a huge game of battleship on the phone. You're taking turns telling each other moves, like C8, and giving responses. If you lose your concentration, and miss something, the whole game is ruined -- did you try C8 already? Did your opponent sink your battleship? Now imagine your little sibling picks up the extension and starts yelling \"d 10! X eleventy one! Sixty q!\" You have to backtrack, maybe start the whole game over again. Your computer has the same problem when you interrupt it. The sequence of numbers it's using to talk loses meaning when a chunk goes missing."
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7b3giq | Why do CPU cores always come in even numbers? | For example, I've never seen a tri-core processor, or a penta-core, or a hepta-core. Is there a reason for this? | Technology | explainlikeimfive | {
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"AMD Phenom processors were triple-core - the Phenom X3 series. The Xbox 360 also had a triple-core processor from IBM. Playstation 3 also used a processor with an unusual design - one main core and seven extra smaller cores.",
"Two main reasons: * Addressing. The computer need to tell which core to use, and with binary, even numbers means there is minimal waste. For example, 2 bits could adress 4 cores, so why use only 3 (1 bit could only address 2 cores)? * Chip space. The cores are pre-made blocks that are rectangular, usually more or less squarish. It's easier to pack the chip to use available space with an even number of cores.",
"Symmetry. It keeps things simple, scalable, and easy to position...dies next to memory etc. There have been many tri core cpus since this is an easy way to sell 4 core cpus that have a defective node...gpus are essentially low ipc cpus with insane core counts and commonly have only a specified number of nodes operating since they are counting on every card having defective nodes....we are looking at you titanXP..."
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7b3ulj | with wildly different writing styles, left to right, right to left, and more importantly in columns, how do international programmers make everyone's name display correctly? | Basically, I play online games, and was wondering how usernames or titles are displayed in vertical text cultures. Everyone I play with or against has a name that reads left to right, like this paragraph. But say, I play with someone from Asian country who generally writes their information in columns, how would their name be displayed? How would a programmer make the two different format styles function, if it's even a need? | Technology | explainlikeimfive | {
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"Most online only sources use the standard English model when they're expected to be used internationally; even ones that are developed in places like Japan or Korea. If possible, they also like to make regional specific alternates, which is called \"localization\". With regards to things like news agencies, they tend to localize their websites. If you're accessing from China, for example, they'll have their site formatted in the Chinese standard. This involves having native speakers on staff, but it definitely pays off for making things accessible."
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7b3y1q | How do pirate streaming operate? Where do they get the resources to host such large amounts of content? | Technology | explainlikeimfive | {
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"text": [
"There’s a site that hosts an embed. They don’t have much legal exposure because they haven’t downloaded and are not hosting the actual file. By embedding the stream they’re just functioning as a search engine, sort of, for the unlicensed content. The site actually hosting the stream has more legal exposure. But how do they have the resources? Same way any site does... ad revenue mostly"
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7b582k | Why do so many VR game developers claim that free roaming in first person games plays terribly and use teleportation instead (e.g. Doom VR, Skyrim VR), yet games like Resident Evil 7 VR completely disprove that claim? | Technology | explainlikeimfive | {
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"text": [
"Because having your senses tell you that you are moving forward when you are not is disconcerting and can cause nausea. And even if some people can handle it, people who build a game from the ground up for VR aren't going to ignore the many people who would not enjoy a free roaming VR experience.",
"Teleportation is *definitively* less nauseating. Some people prefer smooth movement (myself included), but those people have stronger stomachs than the average user. The exception is cockpit games, where you still have a stationary frame of reference around you even as you're moving and rotating.",
"Artificial locomotion in VR is still an area where there's a ton of experimenting and learning to be done. The biggest concern isn't that it 'plays terribly', but rather that a significant portion of the population is prone to 'VR sickness', and artificial locomotion is one of the prime causes of that. Various techniques have been developed that generally lessen the negative effects, and some people have been able to build up a tolerance over time, but it's still a pretty big issue. Not many people are interested in playing games that make them physically feel terrible. With the VR industry being so young and fragile at the moment, a lot of VR developers are concerned about the possibility of a bunch of people's first experience with VR making them feel sick, and potentially pushing them away from the platform. Within the VR industry and enthusiasts, it's not as much a belief that free roaming has no place within VR, but rather a sense that a significant portion of the potential user base is subject to VR sickness from it, and financially it's probably not the best decision to make a game that's essentially unplayable to those people. The 'ideal' solution is for your game to include a range of movement options, from teleportation to unrestricted free roaming, and that's what the current VR player base generally argues for. Although from a developer's point of view, that's usually a significant increase in development time/costs/etc. and it can get especially tricky when trying to balance those various movement systems if you're making a competitive multiplayer type game. There's pluses and minuses to all the different movement systems that people have come up with so far. The big plus of teleportation is that it rarely makes anybody sick."
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7b69cz | Why is it so hard to make a current-gen console emulator? | Technology | explainlikeimfive | {
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"An emulator is a program which uses a computer to pretend to be a different computer or console. When you run programs natively on the console, you push a button and the console calculates a response. When you push a button in the emulator, it can't just calculate a response directly, because that response won't be in the same format the game expects - instead, the emulator has to do extra work to decide *how the console would perform that calculation*. If one of your friends asks you what your favorite candy is, you can answer immediately. But if they ask what your *brother's* favorite candy is, you have to think about it for a minute. Similarly, an emulator needs some extra time to do those extra calculations. But games need very rapid responses, so pushing a button has an immediate effect. That means the emulator needs to run on a computer which is a lot faster than the hardware it's emulating. Not a big deal when you're using a modern quad-core processor to emulate a Super Nintendo. But modern consoles use a lot of the same components as modern computers, and are roughly the same speed. That means there's not really any time to do those extra calculations.",
"An emulator tries to respond to the software in the same way that the real system would. For example, some games exploit unusual behavior or glitches in the hardware, and an accurate emulator will faithfully replicate this. This means that the more complicated the console system is, the more complex the emulator becomes. Perfectly replicating the console is not possible on current hardware, so that some sacrifice of accuracy is necessary. And now you're dealing with all sorts of bugs in many different games that pop up because of that lack of perfect accuracy. Finding special handling for each of those takes a lot of development work. There is an emulator, DICE, that mimics the Pong console down to the very circuits--it's *exactly* the same. No current hardware could do that for a Playstation 4 and let you play a game in real time. Even consoles like the SNES can't be emulated with perfect accuracy and still run on consumer hardware.",
"Software developer here, CPU instructions do not map 1:1 between different processor architectures. There are subtle side-effects when trying to faithfully reproduce a foreign instruction on a host platform. There are incongruencies in timing, memory access, instruction cycles, and interrupts. In order to reproduce some of these effects, an emulator will have to perform them in software, which lends to additional overhead. When trying to keep instruction timing in sync with the original platform, some instructions may execute too fast, so the emulator has to wait to deliver it, or maybe it executes too slow, so the rest of the emulator has to wait for it to arrive, and the emulator is trying to pretend that the slow instruction on the host CPU is actually very fast in the emulated environment. This timing is crucial because old games especially didn't use calculus to pace a game like all modern games do. Instead, they relied on the speed of the CPU. So if you run on a faster CPU, the whole game would run faster. Are you old enough to remember when x86 clones all had a Turbo button? This was to slow the CPU down to properly run older software that was written so naively. And then you have to consider older platforms especially were realtime, and your emulator is running in a multi-tasking OS, so the emulator is going to be interrupted, and so that has to be taken into account. And on a PC, you have any number of video hardware capabilities that won't map to the original platform. In order to faithfully reproduce the original NES would require an x86 processor running at 5 GHz. No emulator or hardware exists that does this, and great compromises are made to provide a suitable user experience. Most people don't notice or care, but a faithful reproduction will also include all the bugs of the original platform. I have friends who will only play Tecmo Super Bowl on the original NES because no emulator spills the runtime data into the video buffer on the bottom of the screen like the original, and the game doesn't lag when too many sprites are on the screen like the original. This is part of the experience for them and they swear it changes the game.",
"People answering “because of architecture” or “processing power” are not really correct. They used to be correct, but not so much anymore. The Xbox One and PS4 use standard x86 CPUs just like your PC. They also use essentially off the shelf motherboards, ram, and graphics chips. The drivers are different, but driver compatibility layers don’t add much overhead. The difference is one of complexity and will. As the newer consoles and games have approached PC level complexity and power, the ability for relatively small groups of reverse engineers to legally make emulators has been reduced. Note that to legally make an emulator (at least according to US copyright law), you cannot have anyone on your team with inside knowledge- you must be entirely flying blind while reverse engineering the process. For a simple system like the N64 or SNES, not a huge deal. These days, there’s just not enough people interested in putting in the massive amount of work it would take to emulate a modern console."
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Subsets and Splits