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5zjth7 | Why do batteries put in the freezer last longer, but my phone battery drains faster in cold weather? | First, are these assumptions correct? I've heard both, somewhat anecdotally, so I'm wondering about the interaction between batteries/electronics in general and temperature. Thanks! | Technology | explainlikeimfive | {
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"First, understand that you're probably talking about different kinds of batteries. \"Regular\" batteries are probably alkaline batteries. Your phone has a rechargeable battery and that's probably a lithium-ion one. Those batteries use different chemical reactions, so it's not surprising they react differently to different conditions (including cold). Now, that said, alkaline batteries *do* self-discharge *slightly* slower in the cold, but that degree is minuscule and not worth the effort of cooling them. Where that came from is that alkaline batteries discharge *much* faster in high heat. So as long as you don't store them in the oven, you're fine. LiIon batteries *are* more sensitive to cold, but again, as long as you're in the normal range of Human temperature tolerance, you're fine. Just don't store your *phone* in the freezer. And if you live in Minnesota, try to keep your phone in an inside pocket. Basically, you don't have to go out of your way for your batteries.",
"Those are two different meanings of \"last longer\". A battery stored in the cold (freezer might be too cold, depending on battery, fridge in a moisture-proof container is probably better) will last longer in the sense that it will age slower. All batteries lose maximum capacity over time, even if not used, and eventually after a few years they have to be replaced because they can't hold a good charge any more. Keeping it cold will make it happen slower. A battery that you're actually using will last shorter in the cold in the sense that it'll run flat and have to be recharged sooner."
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5zjzcp | Why do bluetooth speakers make that odd noise when a mobile phone is brought close to them | You know, that odd , rhythmic sound they make when a mobile phone is within close range | Technology | explainlikeimfive | {
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"It only happens with GSM phones. The frequency GSM phones operate at is picked up by the speakers as a signal. The speaker then outputs the signal. It comes across as staticish because it's speaking cell phone not speaker.",
"You mean this noise? URL_0 It's not just bluetooth speakers, any speaker can potentially do it. It happens when the phone is transmitting \"loudly\" to get a signal to the mobile phone tower far away. The speaker circuit is designed to convert relatively small pulses of energy into relatively large wiggles of the speaker to make noise, and the energy from the phone can unintentionally make it do it's thing."
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5zk53u | How is a wire tap actually done these days? | I just remember seeing in movies the FBI sneaking into people's homes and taking apart their phone to "install" a "wiretap" or whatever. I was just curious, if the government has the "ok" to put a wire tap on someone's cell phone, or house phone, or business phone, how is this actually accomplished? | Technology | explainlikeimfive | {
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"Nobody sneaks into anybody's house to bug the phone. They tap the wires right at the phone company. Also keep in mind that just because you have a wireless mobile phone doesn't mean that your calls don't go through wires at the phone company. They absolutely do.",
"The phone company have a lot of routers that route phone calls and Internet traffic between their end points. These routers have the ability to also route selected traffic to a third location for debugging and monitoring. When the FBI get a court order to wiretap the traffic on your home phone, Internet line or cell phone then they send the list of connections to the phone company who configures their routers to send a copy of all traffic to lines set up by the FBI."
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5zkfzu | What is the worst that can happen if you turn off the computer when it states "Do not turn off your computer"? | Technology | explainlikeimfive | {
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"With older OS's you could really risk disk and registry corruption when the computer would lose sudden power, however, with Windows 10, I'm seeing little to no effect. My computer doesn't seem to run chkdsk or anything after losing sudden power, and even my Office365 excel and word applications seem to successfully present me with my unsaved work next time I start them up. Pretty impressive progress, actually. Context? So, I've been a tech for about ~20 years now and I've worked with all versions of windows going back to 3.11 (ahem). My cat insists on using my computer tower as a means to gaining access to the kitchen counter and he REGULARLY hard powers off my computer by doing so. (I'm running Win10 home).",
"The worst thing that could happen is that it was performing critical updates to your computer OS and it fails in the middle, rendering your OS corrupt and making it impossible to boot. Maybe your hard drive crashes too and destroys the drive. Then a shark fails through your window and bites you. The first two are much more plausible.",
"It is not advisable to suddenly interrupt the process of writing data. Usually you shouldn't cut the power of your computer at any time. Any running program might write data at any time, either on your hard disk, USB drive and even over the network. Even though modern file systems do a good job of recovering from partially written files, the files can still end up in a way that the application itself cannot work with (including your operating system). During a system update, most likely your operating system is dealing with very critical files. That's why it explicitly tells you to not turn off your computer (as in not interrupting the power supply). Your whole system might become unable to start. But you really shouldn't do that at any time. P.S. Video games also advise the same while saving your game for the same reason. You might not be able to continue from your last save point.",
"Think of a computer like an onion. We only interact with the outermost layer - we click here, type there, things appear and everything is awesome and pretty. At the innermost layer things are not pretty - it's hot and ugly. Everything is very very small and happens very very fast. Over the years, we've been putting more and more layers of abstraction on top of the core of the computer. Some of these things are very recent and grand (the Internet comes to mind) while others are very old and basic (working with numbers instead of how sparky a particular piece of metal is feeling). Most times, only people which masochist personalities or more curiosity than sense (on their resume it says \"kernel developer\") look at the inner most layers - which are in some ways the most and least important. If they don't work, nothing else will...but you can't really DO anything. Also, we've managed to solve many of the problems at the lower layers so that we really don't need to think about them any more. However, sometimes things break, or the engineers realize they made a mistake and need to fix it. At the highest layers of the onion this is very easy. The lower you go, the more dangerous things get, because teeny tiny changes can have MASSIVE implications for the higher levels. One of the lowest layers of the onion is called the BIOS - it's what lets the computer know it's a computer. Imagine if every time you got up you forgot where you left your body parts when you went to sleep, and couldn't do anything until someone came in and said \"hey this is your leg and that's your brain and over here is a spleen or two\"., and then gives you a folder reminding you who you are as a person because you forgot that too. That's the BIOS's job. It lives on a special chip on your computer and only comes out to wake everyone else up. Sometimes the BIOS needs to be fixed because you got new body parts that he doesn't know about. If you turned your computer off while upgrading your BIOS (\"flashing the BIOS\", which basically means wiping it out then remaking it from scratch like the teleporter from Star Trek) your computer is borked, because it doesn't know it's a computer anymore. The onion becomes hollow and everything just implodes and it's just all bad.",
"I did this to a PS3 when it was brand New Years ago because it was taking so long to install updates. I was forced to return it because it never started back up."
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5zlxbb | Why does youtube/netflix load videos so much quicker than facebook/twitter? | My internet is a bit rubbish a lot of the time. Even so, the majority of the time I can stream netflix and youtube videos fine. However, even when my internet is good, I'll often have to pause a facebook or twitter video to allow it to load before I can watch it without constant pausing for buffering. What's up with that? | Technology | explainlikeimfive | {
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"Your internet is only as fast as the weakest link between you and a server. Youtube (and Netflix too, I'm sure) has a lot of load-balancing and caching servers that are very close to, or in an ISP's backbone network, which means the route from you to a lot of youtube content is very short and unlikely to pass through as many bottlenecks. Of course, Facebook and twitter also use load-balancing servers, but videos aren't their primary product, like it is for Netflix and Youtube. Having slowly loading videos hurts netflix a lot more than it hurts facebook, as facebook has many other features that keeps users on the site, and they need to spend resources on these parts of their site as well. Netflix only has one thing they need to keep running so they can focus all their resources on that."
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5zmrel | How do we take pictures of space while the earth is spinning? | The earth is spinning at 30 m/s. Wouldn´t every single movement prevent us from taking clear and sharp images of galaxys/planets/stars? Especially at such distances? | Technology | explainlikeimfive | {
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"That's only one rotation per day, or roughly 0.25º per minute. Long-exposure photography of the night sky shows exactly the effect you would think, but on the timescale of less than a second, it's fine.",
"That works out to only a degree every 4 minutes. But you do make a fair point and a lot of amateur astro photography does show the trailing of stars on long exposures. If you can gather more light or make up for the spin you do get clearer images, more sensitive sensors become more prone to noise, though."
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5znsal | Why does wifi have seemingly random "slow days"? | Aside from running programs, what other factors would have an effect on the speed of wifi? If one were to keep the factors like "amount of people using" constant, and other controllable human factors, what else would make the wifi fast or slow on seemingly random days? I swear I'm not just searching for tech support, just something that happens to more people that I thought. | Technology | explainlikeimfive | {
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"It's possible that multiple households have set their wifi signal to the same channels. Wifi occupies channels in the same way that televisions do. The difference is that multiple wifi sources can occupy the same channels and create interference with each other, like how its hard to listen to one person web everyone around a table is shouting. You can limit this by moving your network to occupy unused changes on the wifi list. Any wifi analyser app on android should be able to show you how many of the surrounding networks are using what channels. From memory, changing to channel 11 is generally the quietest channel.",
"There's too many factors at play to assume that your wifi is having an off day. I'm not an expert but I imagine that similar to your electric bill there are peak hours of traffic. I guess there are nodes in your area which sometimes get sudden peaks of traffic and your ISP may not have sufficient infrastructure to support these peaks. Which in turn gives you shit net. Your modem router could also lag if there are too many devices connected as well. That's my uninformed two cents",
"And there's also surrounding wifi and electromagnetic signals which might affect your wifi strength",
"Actual ELI5. You know how walkie talkies have the dials on the top to choose a channel? You and your buddy select the same channel to talk to each other. If someone else were to set up on that same channel, and talk to their buddy, randomly throughout the day you'd have issues talking with your friend because the other pair are talking. Wifi works in the same way, only you can't hear the other pair talking. Also a lot of the channels overlap with each other, channel 1 will cause some disruption for channel 2. For the actual tech support you didn't want, if you have cool neighbors discuss with them about coordinating channels so you don't overlap. If not you could also look into a 5ghz connection, which works with completely different wavelengths that don't overlap."
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5zs55q | If Pac-Man's maximum level is 255 because it's the highest decimal number you can store in 8-Bit binary, how come it can count the score up to millions in decimal even though it's still 8-Bit? | Technology | explainlikeimfive | {
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"They only reserved 8 bits for the level, resulting in 255 being the maximum level. The maximum score for pacman is 3,333,360 points, but that limitation is determined by limited ways you can earn points to begin with. You need at least 21 bits to express 3,333,360, so it is likely that they reserved at least 24 bits (since bits usually come in multiples of 8) to store the score information.",
"They allocated 8 bits of memory to the level counter. That is, the level can be at max \"11111111\"binary. They allocated more than 8 bits of memory to the score counter, which is why it can go higher.",
"The issue with the levels is a result of the 8-bit processor using a single byte (8-bits) to store the current level value. The score is a whole other animal. Depending on methods for display, two different solutions can be used. One of the solutions is space hungry and fast, while the other is less space hungry but requires more process time to display. The faster solution (used in many NES games, but would apply here) is to use a single byte to store each digit. The space is lost because you only need 4 out of the 8 bits to store binary coded decimal (BCD) values. Then all you need is a number of bytes to store data into that is equal to the number of digits that you need to be able to change. The other method (used by Vs.Duck Hunt for certain, but likely others as well) is to store BCD values of the 0-99 range in a single byte as it would use less memory, but the program would have to break each 4-bit component (nybble) of the number out for display reasons. This of course requires more process time to complete as you'd be not only breaking out the nybbles but then (possibly converting them into correct graphics data) and dumping that information to display memory. Trailing zeroes may not be stored in these ways as the game may never change those values. Simply put, if no earned score value is lower than 100, the two trailing zeroes are just plain text, which further reduces needed storage allowing larger numbers. This would result in needing only 5 bytes to store scores in the millions per method 1, and 3 bytes to scores in the millions per method 2. After all that, the final limiting factor is the display space to show the player the values in the memory. Even if you can store values in tens of millions (method two, assuming no score quantities under 100 pts.), you won't be use all the space if you can't display all the values on the screen. These are the common ways to do this as it simplifies the math routines needed to update the score information. Source: Know 6502 assembly language and have begun attempting to write a NES game on my own.",
"They use more than one 8-bit number to store the score. So like you can store 99 numbers in two decimal numbers instead of just 9.",
"Oh boy, you're one of today's [lucky 10,000]( URL_1 )! The reason behind the kill screen is more complicated than simply wrapping around from 255 to zero. Here's a full explanation: URL_0 It's totally possible for an 8-bit processor to work with larger numbers than 0-255 - such as the Pac-Man score. The only restriction is that it has to deal with 8 bits *at a time*. For example, I used to program a Commodore 64 which had an 8-bit 6510 processor, and the way to do larger numbers was to use a \"low byte\" and a \"high byte.\" By using two bytes, you could represent 16-bit numbers: the high byte's eight bits represented the bits that stand for 256, 512, 1024, ..... to 32768; while the low byte's eight bits represent the 1, 2, 4, 8, 16, ... to 128. This way you could go not just from 0-255 (256 = 2^8), but from 0-65535 (65536 = 2^16). Using three, or four, bytes would allow for numbers up to 16.7+ million or 4 point something billion, respectively. Edit: oops, wrong link; that was for Ms. Pac-Man. I think the original is on that same site somewhere.",
"What you do is have two 8-bit numbers. If you add something to the first number when it's reached its limit, a carry flag will be set. You simply add one two the other number whenever the carry flag is set.",
"\"8 bit processor\" means it can \"write\" 8 bits at time. It can use more than 8 bits to write a big number. For instance, you can only write 1 number at a time, but you can write a bunch of numbers in a row to make a big number The people making the game said \"the level number does not need to be big\", so it got a small space in the program. This is like when you fill out a form, and there's a big box for your name but a tiny one for your ZIP code. Your ZIP will be small, so there's extra space to write in your address.",
"Even on an 8-bit processor, you can handle larger numbers, but for each variable in the program, you decide how large it should be. So, they expected the core to be large, and used a large variable. They didn't expect anyone to beat 255 levels, so they used a small variable for that. Why not always use the largest variable available? Two reasons: * Speed. Since the CPU can only work with 8 bits at the time, every operation needs to be don on chunks of the variable, meaning more operations. * Memory. On these early systems, memory restrictions were a very real issue. Every byte counted, so programmers always strived to use the smallest variably available."
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5zsjcm | Why is it still possible to turn your computer off when it's doing updates? | Technology | explainlikeimfive | {
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"It would be a problem if you couldn't. Imagine you're stuck in an update (common in Windows 10 now). Eventually you'll have to use your computer again, but if you had no way to force restart by forcing shutdown first, you've essentially bricked your computer. Operating system updates have become far more robust over the years so it's extremely unlikely that turning off the computer in the middle of an update will corrupt the system."
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5zswyv | Why is it that nearly all minor computer issues can be solved by simply turning the machine off and on again? | Technology | explainlikeimfive | {
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"Stolen, shout out to u/CostcoTimeMachine A computer or smartphone is built around memory that is cleared when power is removed from the system. When you start your computer, software and data is loaded into memory from storage, such as a hard disk. The longer your computer is running, the more likely it is that you run out of memory or that items in memory are corrupted. Restarting the computer clears all memory and reloads content from storage. Edit. By corrupt, I just meant things getting into an unexpected state due to bugs, not low level memory corruption. Poor word choice."
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5zt5bz | Why are there caps on passwords? | Limitations and requirements are irritating enough, why do some things (in my situation, online banking) have a limit on how large your password can be? | Technology | explainlikeimfive | {
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"Their databases were set up with maximum character counts per cell. When configuring a DB, you set character limits."
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5zteqx | I want to design a video game. | Technology | explainlikeimfive | {
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"I would recommend Unreal Engine for creating a video game. It's free at first, but if you're making over $5000 (?) a quarter you have to pay them 5%. It can look great and there is some great asset packs you can get started with. There is tutorials on YouTube for beginners too, so hopefully it will suit your needs."
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5ztjyj | How does Google Analytics track and serve me targeted ads, even though I use a VPN and delete all my cookies? | Title is pretty self-explanatory. I tunnel all my traffic through PIA VPN service. I have Firefox set to delete all cookies once I close my browser. And yet, I will Google something and get targeted ads on third party sites. How are they tracking who I am, and what can I do to stop this? | Technology | explainlikeimfive | {
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"There is a process called fingerprinting, where a site gathers a lot of data on your computer's environment, rather than your internet connection. A web site can detect your screen resolution, browser type, processor type, windows version. With something called WebGL, used for putting 3D graphics directly into a web page, the web page can even detect your exact video card model. This, along with dozens of other tiny but usually insignificant details about your computer lets the web site generate a unique checksum that will be unique enough to correctly identify you as a user across multiple sites, even if you reinstall your entire windows between visiting them. If you on even just one of these sites log in to for example a google account, they'll know that this google user uses this computer, and every time you visit a web page that uses fingerprinting, they can deliver ads that fit your google user profile even if you don't log in to a google account on that site.",
"Do you log into any accounts during that time? They can track you that way."
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5ztw13 | How do the car key unlock button unlock a car and how does it open only that one specific car? | You know, how you press that button on your car key to open up your car from a few meters away. I don't know what it's called lol. | Technology | explainlikeimfive | {
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"When you press the button, it sends out a radio signal with a unique identification number that your car recognizes and responds to. If someone with an identical car uses their remote key, your car would receive the signal, but it would not recognize the identification number and thus not open the door.",
"Transmitters for cars and garage door openers are the same, so we'll comment on both of them. The first generation of transmitters didn't use codes, you'd press it and it would just open anything on the same frequency. When you were the first one in the neighborhood to have that brand of garage door opener it was fine, but obviously it was a problem when your neighbor got one, as well as the local burglar. The next generation used fixed codes; the transmitter and car / garage door opener would either be programmed with a single code. So it would be unlikely that you would open up your neighbors door or car. But a thief still could without too much effort by having the same device, then code sniffers came out that could actually capture a code being transmitted. The current generation use rolling codes. The transmitter and receiver have identical pseudo-random number generators to generate a new code each time. Code sniffers are useless because after one use a code is void. So why does it still work when you press the fob a couple of times trying to get your horn to beep so you can find your car in the parking lot? In practice next hundred or so codes to be generated as valid. With a trillion possible codes this isn't a security issue.",
"Think of your car's radio. It can only receive what's on the station it is tuned into. If you're tuned into a Spanish station, you'll just ignore it because you don't understand it. Your car is only tuned into the station that your keyfob is transmitting on. Your keyfob and car speak the same language, but other cars and fobs on that station don't speak their language. This way, you can only have a few stations (frequencies) and a few languages (codes), but have a lot of combinations."
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5zucze | In order to answer voice commands, smartphones must be constantly listening for the commands: How is this not a massive battery drain? | Talking about the kinds of phones you can wake up or request stuff be done with voice commands like Siri or Ok, Google. In order to pick these up, it must be constantly listening, and that would be a massive battery drain no? Even if you set it up to only search for the commands above a certain volume threshold, that would mean noisy environments would drain your battery faster than silent ones no? | Technology | explainlikeimfive | {
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"It is a bit of a battery drain. That's why many people choose to disable those services after rooting. You can greatly extend battery life by disabling or limiting services you don't really need.",
"I've read some on this: The ultra efficient way of doing this (at least for android) is that the phone doesn't run everything it hears through a power sucking CPU 24/7 ... instead: When you speak into a microphone a select phrase it's turned into a regular and identifiable pulse of electrons. The only thing the phone is doing is looking at a particular circuit for a particular combination of electrical pulses that translates into the real world as \"ok google\". Once the phone realizes you are talking to it specifically it then switches on full recording so it can upload the bit to google, do voice processing, and return a result for you.",
"There's a chip inside some iPhones that are designed to listen for \"hey Siri\" without being a huge drain on battery life. I'm not sure how it works, but that's why hey Siri doesn't work on older phones unless the phone is plugged in. They don't have that chip."
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5zwb4r | Why was Nazi Germany so fixated on Heavily armoured tanks rather than improving their anti-tank shells and technology to combat the Soviet KV tanks? | Technology | explainlikeimfive | {
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"You phrase your question as if it were only just one or the other, when the reality was both options were pursued. But what does 'improving anti-tank shells' mean exactly? Well, there were two main types of anti-tank shells in common use by the Germans, your standard kinetic penetrator round (aka, 'AP' round) and your High Explosive Anti-Tank round. By the time of Operation Barbarossa, the German anti-tank weapons consisted of towed AT guns ranging from 3.7cm to 8.8cm. A number of these towed weapons did have the firepower to penetrate KV tanks from a range. But there's a problem--towed AT weapons are primarily a defensive weapon. These guns need to be towed into position and set up, which is bad if you're on a battlefield that's constantly shifting and, contrary to popular belief, the Germans used a lot of horses to move guns around, which makes it a slower process, especially for the big 8.8cm guns. So towed guns are generally poor for offensive operations, which meant AT duties when on the offense fell to tanks and infantry. The infantry had the ~~ubiquitous panzerfausts~~ Faustpatrone (edit: derp on my part, panzerfaust came in 1943; faustpatrone was the predecessor used at the start of Barbarossa), which was more than a match for the KV's armor, but those things were not easy to aim--effective ranges were usually less than 60m, less so if you want a good chance to hit. What about the tanks? Well at Operation Barbarossa's time, their primary anti-tank tank was the Pz III armed with the 5cm cannon, supported by Pz IV's armed with a short-barreled 7.5cm cannon and the Stug III armed with the same 7.5cm. The Pz III's gun had an armor-piercing composite-rigid round that could punch through the KV's armour, but only at 500m or less. Meanwhile the 76mm guns of the soviet tanks could punch through German armour at twice that distance. In addition, the 7.5cm cannons of the Pz IV and Stug III had high-explosive anti-tank rounds that, yes, could penetrate a KV's armour--but they were armed with very short-barreled cannons that made their accuracy a bit lacking. Edit: in addition, the StugIII and PzIV at the time were predominately for attacking infantry positions and carried mostly high explosive rounds. In other words, being able to penetrate is one thing, but if you have to get in close to do that then you're going to have problems with your tanks exploding before they can get a shot off. So what's an army to do when faced with this issue? The problem isn't the ammunition, it's the guns that are firing them. The 5cm on the Pz III just isn't strong enough to take the kind of explosive charge needed to propel a shot with enough energy to punch through the KV's armour, and the 7.5cm on the Stugs and Pz IV's are too short to reliably hit anything at longer distances (plus I do not know how prolific HEAT rounds were at the start of Barbarossa). Edit: in addition, AP rounds in the non-8.8cm category generally needed tungsten cores to have a chance of penetrating the KV-1's armour, and tungsten was not something Germany had in good supply. Thus, supplies of these rounds were limited. Solution: mount a bigger gun on your tanks. Well, it just so happened that a long-barreled 7.5cm cannon was being fitted to Pz IV's, but that started only weeks before Operation Barbarossa began. The Pz IV was originally slated for support purposes, not anti-tank duty, but it had a turret that could house the longer barreled 7.5cm so it got the new job. The other gun they decided to use was the powerful 8.8cm cannon--put that thing on a tank and you've got a gun that's more than capable of dealing with a KV in excess of 1000m. Slap more armour on it so it can withstand the return fire and you've got yourself a tank that can laugh in the face of KV's. Since none of the current tanks they had could fit the 8.8cm, they had to make a new one, and thus was born the Tiger tank. Please note that I am an amateur at history at best (and in the loosest sense of the term) and this has probably glossed over/simplified a lot of details. TL;DR - it wasn't a problem with the shells, it was the guns firing them. So they made a bigger tank to carry the bigger gun. Edit: I feel like I rambled a lot and could've answered this more concisely...",
"Germany did make some inroads into advanced anti-tank guns, most notably with their squeeze-bore anti tank guns like the [Pak 41]( URL_0 ). These gave excellent penetration but they needed tungsten-carbide shot to be effective. Tungsten-Carbide is also needed for machine tools to make weapons. As Germany had limited supplies of Tungsten Carbide she had to decide between throwing this scarce material at enemy tanks or using it to make machine tools. Machine tools were quite rightly decided to be the best use and the squeeze bore guns were withdrawn from service."
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5zx3jr | Each car has its own key. Why can't that same car key unlock other cars of the same brand and model? | Inserting the key into the lock is one point, but unlocking in terms of clicking the button on the key from a distance to unlock the car. | Technology | explainlikeimfive | {
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"Because the keyless entry device sends a code that the car is configured to accept. Typically a second code (double click) is also configured to unlock every door, and not just the driver's. Obviously, designing them so that they all sent the same code and could unlock any car would generally be unpopular.",
"For physical keys, there are a finite number of combinations and there are more cars on the road than combinations. My family had two Ford cars with compatible keys. The key from either vehicle would open the doors. Interestingly, one car could be started with the key from either car. The other car the key from the second car would turn but not start the ignition. Similarly, at my church, there were a number of occasions where someone left their lights on in the parking lot. An individual would try his key in the car and and find that it would unlock it so they could turn the lights off. It probably helped that I grew up in Dearborn, Michigan, hometown of Henry Ford and Ford Motor Company's world headquarters so a majority of the cars on the road were Fords.",
"yes it can, once after dark we went with my friend for something in his trunk, he could not find it there, but then the real owner of the car came and he was not very happy we went through his trunk, because friend confused his car with another, they were same model, parked nearby, though different color which we didn't noticed in darkness luckily this was public parking in Europe so we were not shot",
"I actually had an issue with this once long ago. Had a 1978 Pontiac Catalina. Ugly green car. I went to the grocery. Went in, came out. Got in car and drove away. Then realized I wasn't driving my car. Same year, same color, and equally ugly Pontiac Catalina. Went and reparked it and found my car a row over. Sigh. I waited around to explain to the driver what happened. But gave up after a half hour and just left. Still can't believe my key opened and started another car. Not high odds."
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5zy06l | What does it mean to "root" a cell phone or tablet? | ELI5: What does it mean to "root" a cell phone or other device (tablet)? | Technology | explainlikeimfive | {
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"On UNIX systems, the superuser or administrator of the machine is often called root. If you are using a UNIX machine, you'll usually set it up so you are running as a normal user except when you need to execute specific commands on it that need superuser or root powers. The expression of \"rooting\" your phone/tablet means basically that you have modified the software on your device such that you have the maximum powers on that device. iOS and Android devices protect the user by not giving them root powers over the device. This is to protect the user from their own inexperience, preventing them from inadvertently installing problematic software (viruses, trojans etc.) (Or at least that's one explanation. The other is that the manufacturers are evil megalomaniacs trying to deny you your freedom etc.) Rooting your phone is basically overriding that control and controlling it for yourself. **Warning:** Rooting your phone or device may invalidate your warranty. More importantly, rooting your device without knowing something about how to operate it properly is a recipe for security issues. Be very cautious, read carefully and always keep backups if you root your phone. If you screw up, you may end up [bricking]( URL_0 ) your device.",
"Basically, it means giving yourself the rights to install, modify or delete anything on the phone. Usually, phones are protected in a way that prevents unexperienced users to delete an important file and corrupt the whole phone. By rooting (or jailbreaking for iphones), an experienced user can access more stuff and personalize their phone to their liking. Of course, knowing what you are doing is very important, because this is risky."
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5zyxcw | When you delete something off of a phone or camera, where does it go? | Technology | explainlikeimfive | {
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"Nowhere. The data is still there. Your storage medium, be it a disk drive or flash memory, uses some storage space to keep a database of where your files are, physically, on the medium, as well as other meta-data. When you delete something, the minimum number of entries in these tables are overwritten. Typically this is simply overwriting the first byte of the entry with a binary zero, all the bits are zero (this isn't the same thing as the 0 character, which is encoded binary). That's it. Computers are as lazy as possible. Now that the entry is invalid, it can be reused when it's needed, and the blocks of storage space that contain the original file contents are no longer allocated, now that the tables have been invalidated. They'll get overwritten with new data whenever - it's up to some algorithms when to use a block, and the last deallocated is not necessarily the first used. So with the right software, you can search a disk for bytes that look like data, deduce what the bytes encode, and reconstitute the original file. Over time, as blocks get used, you'll start losing information until it's all gone. If you're security paranoid, you can get file shredders that will overwrite the original file first, before deletion. This is a good way to send flash memory to an early grave, as they're comparatively limited to the number of writes possible.",
"Technically it doesn't go anywhere. The phone just forgets to look there. No really, this is how data recovery from borked hard drives and stuff works and why paranoid security types \"wipe\" drives and devices to make sure the info is unrecoverable. In any filesystem there's the bits and bytes that make up your data. These are organized into equal sized chunks called blocks. If a file doesn't fit entirely into one block, the last part of the previous block is a pointer to the next.. and so on. And the pointer to the _first_ block is held in a special index called the file table. It would say the first block of file C:\\folder\\foo.jpg is block #293847. Now, when you delete foo.jpg, its not actually erasing the bits and bytes in all the blocks. It simply deletes the listing in the file table... so the operating system thinks block #293847 (and all the other blocks of foo.jpg) are available. I mean they must be, there's no file in my file table that uses it!"
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6001cs | how is mobile data different than a network? If I am connected to an unsecured network, wouldn't I be at the same risk as if a malicious person were on the same mobile network? | Technology | explainlikeimfive | {
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"No, the protocols are different where the mobile network has individual encryption to each end user. A wifi network only has one encryption for all its users."
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600fso | How do video game developers in a team share files and projects in a game? | Technology | explainlikeimfive | {
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"Like any software development, there are various version control systems (VCS) applications that help keep track of source code an resource files, allowing different members of the team to access the latest and merge changes. A lot of open source projects use Git, hosting on Github while private companies may use something like Subversion or Clear Case."
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6013jm | Why are we moving toward chip cards rather than swipe cards for our Credit/Debit cards? | Technology | explainlikeimfive | {
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"Because the RFID cards generate a unique, encrypted code every time they are used, making them substantially more secure.",
"They are much more secure. They use a 1-time code to verify the transaction. Swipe cards have all their data on the magstripe. The only area chip cards aren't more secure is online transactions, that's where the benefits of something like Apple Pay really comes in, they use a 1-time code as well as a number specific to your device (instead of the card number), and is verified via fingerprint or pin code.",
"Chip cards are most secure as they require a PIN just like your ATM. Mag swipe is really just an error free way to read the card #, the only security is the clearing agent relies on your signature at the bottom of the slip to authenticate the transaction. NFC which some here have mentioned but you did not, is similar to mag swipe in that you need to physically possess the card, but there is very little authentication security otherwise. This is why there are limits (mine is $80) on NFC/Paywave/etc transactions.",
"This article is pretty OK: URL_0 Quote from it: > But unlike a simple magnetic strip, the chip interacts with the machine that is reading it, in order to encrypt the data and authenticate it more securely. In effect, the credit card and its reader have an encrypted conversation in order to ensure the credit card is valid, while a simple (that is, “dumb”) magnetic stripe merely recites your credit card number and expiration date to any machine that can read it. It is this vulnerability that allows credit cards to be so easily cloned for fraudulent purposes."
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601s50 | What does MuleSoft do? | Technology | explainlikeimfive | {
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"The basis of Mulesoft's offering is the mule Enterprise service bus (Mule ESB). For the non technical, a bus in computer science is something that can transport data for a variety of reasons. (Hence the term bus, it easily transports many different things). The ESB allows for extremely fast creation of integrations between different software services. Let's say you own a retail store... You pay for a point of sale software system, maybe you have an advertisement campaign which uses software, you may also have a separate application for managing your inventory. I'm sure you can imagine how the information and process of each of these systems can help each other. Unfortunately, to enable software to work together, there is often an expensive piece of custom integration software to bridge the gap. Sort of like a translator for people who speak two different languages, but automated. Mulesoft's core, the ESB makes that expensive custom integration software extremely easy to develop. The rest of Mulesoft's products are focused on how you can use that tool and latest/innovative technological ideals to organize a gigantic corporation. This helps teams be autonomouis and provides means for each piece of software to be reusable and create leverage for an entire corporation. Mulesoft is making large scale software integrations possible for some of the largest corporations in the world. The offerings allow for smarter and more agile organization of people and assets around each software service. Mulesoft sells tools for development, management, and integration of companies' data and process, on whatever scale is necessary. If you have more specific questions, I'd love to answer. To keep this eli5, I should stop here. Let me know if confusion persists"
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602pwq | Why is region lock a thing? Is it even remotely beneficial for anyone? | So I live in a country where the Netflix catalog is about 11% of the total library.. and even with a VPN, I may not be able to access the shows I want which is readily available in the US. Why is there a need to region lock? I also want to purchase Nier:Automata on Steam(a video game), but apparently this game doesn't show up on the steam library for me as it turns out, it was region locked. I want to pay money for content but it seems like these developers/publishers don't want me to.. So I want to know, what is region lock even for? | Technology | explainlikeimfive | {
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"There could be many reasons for content not being available in a specific region. A few examples: 1. The content owner wants you to get the content in another way (popular for sporting events where the content provider will do a local blackout to increase game attendance numbers) 2. Monopoly; a conflicting provider has signed an exclusive deal with your area that bars them from allowing other vendors 3. The business environment is such that the content provider is refusing to do business in that area for a number of reasons. 4. The content distributor doesn't have the rights to distribute this content in that region. (Ex. Netflix goes to Disney and wants to purchase the exclusive rights to distribute Disney content throughout Europe. Amazon comes along and goes to Disney and Disney says no can do about Europe, you're still free to distribute in other areas but Netflix owns distribution rights in Europe) I'm sure there are others. Also number 4 is probably most likely for where you know they have the content but just don't show in your region.",
"In addition to what's already been said, there are sometimes legal or regulatory reasons. For example, where movies are concerned, censors in Europe tend to be more tolerant of sex but less tolerant of violence than their North American counterparts. Some European countries have trouble with games that glorify or make light of the Third Reich.",
"Game costs $60. For countries A that's ok and affordable For countries B that's very expensive and a few days worth of work The game would have to cost like $20 in countries B to make it as affordable The region lock is the only thing stopping countries A from buying the game from countries B for 1/3th the price (online, delivery). Selling your product in huge amounts in countries B for pretty cheap while not selling much in countries A for regular price is bad for business. Edit: formatting",
"On top of what's already been said, region lock also goes back to a time when media was released at vastly different times depending on location. Now, most things get a near-simultaneous release worldwide, but pre-2000, Europe might have to wait up to a year to get a movie made in the US. Original region lock was usually physical, like SNES cartridges being different shapes so they wouldn't fit in foreign consoles.",
"I didn't see any answers that were satisfying to me. Region locks on film and TV come from funding of movies and regional requirements. An independent movie distributor has a very limited area they can serve. It takes real local knowledge to know how well a movie will do, to have the local marketing connections, etc. These independent movie distributors buy only the region they actually know. So a small distributor might buy movies for only the Benelux region (actually exists, Belgium, Netherlands, Luxembourg). Now if NetFlix or anyone else wants that movie in Benelux, it has to be licensed from that small distributor. With over 300 regions around the world, you would imagine this is complex, you would be correct. Movies are made this way because movies are expensive to make, and each region is only a small portion of the overall value for the movie. This has lead to other complications. Certain regions, like India, have a long process to have a movie approved for distribution. By separating India out from the rest of the world that delay only affects India. Other regions have language requirements. The US actually has accessibility requirements that every movie have English subtitles. All these local rules make it very hard to release a movie worldwide. Just look at the backlash even Disney experienced because Beauty and the Beast has a \"gay moment\" that is not allowed in Malaysia. We are seeing normalization of the rules. The EU has been debating for a couple years now forcing all of the EU to be one region for distribution. This change is a subject of heavy debate within the film and television industry. If you imagine those debates are complex, once again you would be correct.",
"Region lock allows the content owner to sell the rights for different amounts in different areas. If there was no locking then people would only ever buy from the cheapest country they could find.",
"In the US Game of Thrones shows on HBO for example, in the UK it's on Sky Atlantic. Sky paid a SHIT ton of money for exclusive UK rights, which means if you could watch HBO from the UK, HBO would actually be violating their copyright agreement. The rights belong to someone else. So for Netflix that's almost always the reason, they only own US distribution rights. For video games the problem is usually something else, publishers will often still stick to archaic timetables of release dates based on physical sales. In the old days the US stores would get new stock on Fridays, in the UK on Tuesday (or was it the other way around?) and so sometimes they still stick to that schedule. It's bad and dumb and will die soon hopefully",
"Netflix hasn't negotiated a contract with the content providers in that region. They don't have the right and the cost was prohibitive.",
"It's like how aus wouldn't let them put analysis probing or abortion in the aus release of South park stick of truth. Different laws and different monopoly"
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603nmz | How does Netflix and other services know I am using a VPN? | Technology | explainlikeimfive | {
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"It's easy to determine which company owns which IP address. When you use a VPN your IP is changed from the one you are using with your ISP to the one you are using with your VPN. If your vpn provider own their own pool of up addresses then it's easy to just block all the ip's belonging to that company. If your a smaller company and you are using your providers IP address pool then you are going to have to explain why you need so many IP's (IPv4 addresses are scarece these days, my provider charges me a premium for them basically so I only use what I need) or why you need to change them so often. That can you look very unfavourable and they might just drop you as a company completely. This game has already been played with email spam. So providers are always wondering why you want to change your servers IPs so often. Now IPv6 have a huge address space, but people like NetFlix will just blacklist the block of IPv6 addresses you have instead of just the single address (something very similar happened on Wikipedia recently, a single troll (we presume) was using T-mobile to vandalise Wikipedia, after a number of warnings and the like they just blocked the entire block of IPv6 addresses customers use to connect to the net from editing content on Wiki). NetFlix are contractually obliged to region lock certain content. So looking for patterns such as a large amount of content being served to a small range of IPs with many different logins looks fishy (if that's not a residential ISP) can flag those addresses for closer inspection, and then you wonder \"Why does this server siting in a datacenter login as 50 different NetFlix users and consume a fuck ton of content compared to the average user?\" Just block it and get the owner of the IP to come to you and ask for it to be unblocked.",
"VPNs do not hide the fact that you are using one. The way it works is you connect to the VPN and all your Internet traffic goes to that VPN, who then forwards it on your behalf, just like your home router. Instead of your ISP seeing all the IP addresses you connect to and sites seeing your IP address when you connect, they will see only the unidentifying VPN IP, which is why they are \"anonymous\". Most VPN providers have a set range of IP addresses. If your ISP or a site like Netflix can figure out these ranges (not really difficult), they know you are connected to a VPN.",
"Former Netflix employee here, this is my moment. Often people would call in for tech support and forget they were using a VPN. When we would pull up their account info we could see both the country they signed up in, and the country they were streaming from, which could be a vacation or an out of state relative etc... The dead giveaway was when they lived somewhere like Canada, and they asked about a show that was exclusive to somewhere like Australia. I could never call them out on it directly, but I could let them know that VPNs were against policy, and make note on the account.",
"There is not an official way to determine if a remote user is using a VPN. However, services sometimes just block a range of IP addresses that they know to be connected with a popular VPN provider.",
"A lot of people are saying just IP address, but there's so much more that Netflix is able to do to detect VPN: The big one, and most reliable way to tell is packet size. When you send any information over the internet, network equipment like routers break it up into small pieces called packets. Most networking equipment maintains the same size of packet when sending over the internet. Because VPNs need to add information to every packet, they automatically break up your actual packets into smaller than usual chunks to leave room for their own information. Netflix looks for this smaller chunk size. Typical VPN users tend to be more security and privacy concious than other users. Therefore, they have a high likelyhood of installing browser extensions such as ghostery, donottrack, adblock, and similar. They can build a fingerprint of these users, because they have enough of them. It really isn't packet size, fingerprint, or IP range that they use, but rather a combination of all of them. Netflix and other large internet companies have so many users that the data they can collect and use from them is incredibly accurate. They have a complex system of algorithms that look at all the data and determine if you're a VPN user or not.",
"They know something is up when you connect from a nonexistent country like Australia or Finland.",
"Imagine you are in first grade and this girl Stacey is really good friends with the teachers. She is a kiss-ass - drawing cute pictures of them, telling them how pretty they look - the full package. Now, you asked a teacher a question - when is the next test going to happen. Obviously, you are not as cool as Stacy so the teacher wouldn't answer you. However, you are smart, so you made Stacey ask instead of you and you got the answer you were looking for. This type of thing happened a few times in a row, you told your friends about it and they started doing it as well. At some point the teachers realised what is happening so they stopped answering Stacey (some of you asking the teachers first and then making Stacey ask didn't help). Of course, if you have a friend that is being liked by the teachers AND he will ask questions only for you, then the teachers will never catch on what's happening.",
"They have IP range lists that they are constantly expanding. That's why some VPN's used to work with Netflix and others not. Until they expanded their lists and included more. The VPN I use used to work with Netflix until fairly recently. Then it just stopped.",
"Speculation, but they might record IP history with your ID. If you bounce from Chicago to Malaysia a lot that's a pretty big red flag.",
"It's lame to say this but I went to a talk with the head of engineering for Netflix and I'm not comfortable sharing what he said(he asked us not to but we did not sign NDAs). That said they do much more than blacklist vpn's IPs and can actually tell your actual location without using your IP at all. They moved away from using IPs as a tell all a little while ago",
"Are you using a VPN provider? I suspect Netflix has the most popular ones blocked / blacklisted. You can set up your own VPN server on a computer you own (in the US) and then, when you are traveling, have your client VPN into that. It will appear as if you are surfing from your VPN server and I suspect Netflix won't be able to detect the difference. Setting up a VPN server of your own, if you have a machine in the US, is a little bit of a pain but maybe worth thinking about. This strategy *might* work from machines in AWS/GCP/etc... You can certainly run a VPN server there but I wonder if Netflix is smart enough to block traffic from public cloud providers too?"
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603zgr | Why arent all files zipped/compressed/packeted by default? | So files are zipped or compressed to save space mainly for when they are being emailed etc. Why arent they just all saved like that on all computers? With the speed of computers now, the time it takes to decompressed isnt even noticed. Why not save space across the entire computer and compress them all (apart from operating software for obvious reasons) | Technology | explainlikeimfive | {
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"It takes processing power to de/compress stuff. You notice how smoothly video plays nowadays? Pretty much every computer now has a dedicated piece of silicon for decompressing h.264",
"Many file formats use specialised compression algorithms suited to the type of data, which do a better job than zip can because they're able to throw away some information which won't be missed. A zip file must decompress to exactly the original file, but a JPEG can change a few pixels if it helps to save space. If you zip a JPEG, an MP3, or an MP4, then you won't get any useful reduction in size.",
"You can do this by turning on compression at the file system level. In addition most Microsoft office files are now compressed as well. As to why it isn't done more broadly, it does add some complexity and space is so cheap it doesn't matter."
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6045of | Isn't the freshwater we have to work with just going in a cycle? How are we losing fresh water? | You are told not to take long showers because you're wasting water, but the water goes through the sewers and is cleaned and returned to the water supply, right? Same thing with toilet water, dishwasher, sink, washer, etc? So, where are we actually losing water when we use it? | Technology | explainlikeimfive | {
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"When the water ends up in the oceans, it slows down the cycling a lot. Water in aquifers (the stores under the ground that we access when we use wells) and water on Earth's surface are the cheapest to use. We have been either polluting these (surface) or using them too fast for new water to filter in. We have also allowed a lot of water to go to the ocean(storm water runoff from developed areas) , rather than slowly go into the aquifers through the ground. So the result is we are using aquifer water faster than they are getting refilled. When that water is depleted, all water will become more expensive. We will still have it, but it will either be salty, polluted, or far from where it needs to be, and all of the fixes for this cost money. Sorry if this isn't too coherent, I haven't finished my first cup of coffee for the day.",
"> the water goes through the sewers and is cleaned and returned to the water supply, right? Probably not. I'm my city there is no treatment at all, just a pipe 200m (656ft) long that goes into the ocean. Other cities have various levels of treatment before dumping into the ocean or river. I think it's rare for a city to have enough treatment to make the water drinkable again.",
"We aren't necessarily \"losing\" freshwater. We are simply using the limited supply we have at a greater rate than nature replenishes it.",
"In a typical case, water that is \"cleaned\" by municipal treatment facilities is clean enough to be released back in rivers or the sea. It's not clean enough to be used directly. For example, read [this] ( URL_0 ) about how Las Vegas gets its fresh water from Lake Mead, but treated water is not put straight back in to the lake. Instead, it is released in to something called the [Las Vegas Wash], a river / wetland complex where natural processes work on the water over time, and impurities are broken down or filtered out. Which is fine if you have created a lake to supply you, but the situation in California is different. Much more fresh water is used than the natural sources can supply. So e.g. the Colorado River has basically stopped flowing by the time it reaches the Arizona/California border, and Lake Mead is largely to blame. The \"water table\" under parts of California is being drained more quickly than it's being replenished, making it harder to find fresh water.",
"We have a major problem with this in Florida. As we draw more and more freshwater from the aquifer, the amount of rain and time needed to \"refill\" the aquifer is insufficient. As freshwater levels fall in the aquifer, seawater filters in to fill the space. This process was especially bad in and around the Tampa area, where they finally had to build a desalination plant on Tampa bay in order to meet the needs of the population. As Florida continues to grow, we will continue to see the gradual encroachment of seawater into the aquifer, eventually leaving it completely unuseable.",
"If you live somewhere you depend on rainwater filling a tank for water then as long as your tank is big enough and it rains often enough and you don't overuse water you are fine. But throw one thing out, too small a tank, too little rain, too much water used... you got a problem. No problem, just build a real big tank and be careful about useage and it'll rain eventually... Then you have some people move in, water useage goes up 600% instantly, you can't afford another tank and it's still not raining. Take that to the city and everyone on mains supply water is just sharing a big tank. City gets too big, wastes water or it just doesn't rain for ages and the whole city has a supply problem. The cycle of water was providing excess water to use in places it was collected, that isn't the case everywhere now. The weather can't provide enough rain in some places. More people and industry using more water all the time. There is still more fresh water than needed for all the people, but not necessarily where the people are."
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604beh | How did the world operate before alarm clocks? | Technology | explainlikeimfive | {
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"While the other reply is correct and there used to be a \"waker upper\" what we're failing to realize is that in times that long ago, waking up \"on time\" just wasn't as important. Without widespread electricity it was unusual for people to stay up into the night. Basically most people would go to bed after sundown and wake up at or before dawn. The human body does keep a fairly consistent internal clock if you let it.",
"Time in general used to not be so important. Pre alarm clock means pre industrial revolution obviously, so a much larger proportion of the population would have led an agrarian lifestyle, where the hour of the day is not as important as daylight and weather conditions.",
"Pretty sure it used to be some guys job to wake everyone up by tapping on the windows in the morning, seen this on Qi a while back so don't remember exact details.",
"For most of history, people could only effectively work when it was daylight, and had to work all those hours in order to survive. So the sun was your alarm clock. Later, there would be a bell tower in the village that would ring out important hours. Later still people would hire knocker-uppers, usually a local too old to work, to come by and wake them up. Also, punctuality wasn't as much of a thing. Without accurate timepieces, there were no 9am meetings to be late for. Most people lived and worked at the same place, so you they were needed, they would be easy to find."
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604fuu | Why does rendering gameplay in video editor take significantly more time than recording live gameplay? | If you really think about it, each frame needs to be calculated, drawn and rendered, from scratch during live gameplay and can be recorded at crazy high fps, when compared to rendering the same footage after minor / light editing, when each frame in the video file is already fully drawn out and all the program needs to do is to put the file together again after going through and editing a few frames. | Technology | explainlikeimfive | {
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"Rendering a video is doing more than just putting images back to back and then creating a video that puts those images on the screen. It also does a lot of compression to the video so that the file size is much smaller and can be transmitted across the internet without using up all of your data limit. Lets do some quick math. There are 1920x1080 pixels in the majority of modern of screens (some people are even moving to 1440p which has even more more pixels). A single 1080p image uncompressed is just over 3 MB. At 25 frames per second you would reach a gigabyte in about 13 seconds of video time. Most videos are much longer than 13 seconds, yet we stream them for only megabytes of data at a time. This is where the difference between rendering and real time come into play. An Nvidia 1070 can pump out terrabytes of operations and video every second. But the renderer will take these images and process them down into a file size that's manageable for the internet. A common technique is to take large areas of a similar color/pattern and just say, this area is this color/pattern. By doing this we can save a lot of data. Specifically pertaining to videos, we also try to determine which parts of the video are updated in each frame and only redraw those parts. All of this is expensive and the more compressed the file the more expensive it is. Edit: Here's a site that you can look at to see how big of a difference compression makes. URL_0"
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604s7n | How do chess games determine the best move | When you play chess against a computer im sure they brute force every move, but from having every possible move how does it determine which is best. Edit: explainning a very simple choosing algorithim would be nice as well | Technology | explainlikeimfive | {
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"You're correct that computers simply brute force every possible move, but beyond that, every possible sequence of turns for x number of turns into the future. Every program has an algorithm for the value of a particular move, general based on the value of capturing specific pieces vs. pieces lose. More sophisticated programs will weight moves by board position, likelihood an opponent will fall for a trap (ie probability an opponent will make a particular move), ability to play to a stale mate when defeat is imminent, etc. Basically each move sequence represents a score, and the computer is just trying to optimize the score."
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605dxo | What is Unix time and what is it used for | Technology | explainlikeimfive | {
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"Unix time is how computers keep track of time. Unix time is the binary number for how many seconds have passed since 00:00:00 UTC on 1 January, 1970. It is used to keep track of the date and time in pretty much every application on computers and phones because it's such an easy algorithm to use."
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605e86 | How does Google & Youtube backup my files, videos, pictures and not deal with hard drives failing all the time? | Technology | explainlikeimfive | {
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"Hard drives are always failing. The drives are in arrays, your data is stored across multiple drives instead of just on one drive. Parity is used to reconstruct data when a drive in an array dies. For an example of parity we can use addition. We know that 1+ 2 = 3. Let's say you erase one of the numbers so you have ? + 2 = 3. Even though we've erased one of the numbers we can calculate what the missing number is using our old friend Algebra.",
"They have back ups for their back ups and, to the best of our knowledge, they *are* swapping out a million hard drives a year.",
"Let's say you have an array of 10 hard drives. The drives themselves aren't going to go bad on the same day. They happen one at a time. If they have that array set up correctly, they'll be able to tolerate 3 or 4 failures before there is data loss. So as one fails, they just hot-swap in a new drive. Repeat as necessary. Google will have a bigger example than that, but that's the concept. They would have cabinets of disk that are redundant with other full cabinets of disk."
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605p26 | How is a CPU die separated into different "cores" and "threads", and what even are threads as opposed to cores? | Is it a software thing, or are they partitions of transistors inside the die? If they're just partitions, how do the CPU manufacturers make "barriers" between each partition? | Technology | explainlikeimfive | {
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"Traditionally, one core would handle one thread at a time. if it needed to process information from another thread, the first thread would be put on hold for a short amount of time until the core was done doing what it needed to do on the other thread. However, a core contains several types of circuitry. Let's say one core has some circuitry to do integer operations, and some other circuitry to do floating point operations. If Thread1 is currently running and it performs nothing but integer operations, the floating point circuitry is completely unused, and the core is wasting some of its capacity. If Thread2 wants to do some floating point operations, the core needs to stop Thread1 even if Thread1 isn't actually using the floating point circuitry, and now it's the integer circuitry that's not being used. Hyper Threading (or the more general name, Simultaneous Multi-Threading) allows a core to load two threads at a time. If the system manages to match the threads perfectly, you could have Thread1 using the core's integer circuits, and Thread2 using the core's floating point circuitry at the same time, and the core would be much closer to 100% efficiency. There is some overhead, and some inefficiencies in the system, but for example two threads running at 90% the speed 100% of the time is faster than two threads running at 100% the speed 50% of the time. In this example, the core would be able to finish 80% more work in the same amount of time than it would be able to without Hyperthreading. This is a simplified explanation of how one core runs two threads. It is in reality a bit more complex than this. A core needs some extra circuitry to be able to manage two threads at the same time, but the extra circuitry needed to do this is well worth it when you're in a situation where a cpu needs to manage a lot of processes. To address one of your questions directly: When a processor has 4 cores and 8 threads, this is a hardware property of the chip. Each core has circuitry that allows it to perform calculations on two threads at a time, instead of just one. This is referred to as \"hardware threads\". There are also threads in your programs. One program can be programmed to have two different threads. Your music player might have one thread that handles the user interface, one thread that handles audio decoding, and one thread that handles the saving and loading of files. This way, the music won't stop if the graphical user interface hangs for a second. It might be worth noting that in the past, before we had multiple cores on one cpu, or multiple threads per core (Pentium 4 had 1 core with HT), computers never actually did two things at the same time. If you listened to music while writing a mail on a pentium 3 in 2002, your cpu was actually switching between playing music and updating your mail program hundreds of times a second, never actually doing the two things at the same time."
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606u6w | How could whatsapp knows that I may have new messages even without internet. | Sometimes when my network data is off and im not connected to a WiFi I get this message and it is always true. However, sometimes my phone connects automatically to a saved WiFi that actually requires signing in which I didn't do. | Technology | explainlikeimfive | {
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"Simple answer: they don't. They likely just want to entice you to get back on the platform. At most, they run a machine learning algorithm on the frequency at which you receive messages and store this locally in each person's phone, thus over time, predicting with some accuracy if you'll get a message."
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606wzi | How do website advertisements generate revenue? | Technology | explainlikeimfive | {
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"text": [
"Depends, but generally both. \"Impressions\" are the number of times an ad is loaded. Impressions are very cheap; millions of impressions might only generate a few dollars. Clicks are \"interactions,\" these generate a TON more money for each interaction. That said, this might be a general \"click = $\" or could be a more complex \"if they click and end up buying the product, you'll get a 10% fee.\" Just depends on the specific deal."
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6084fx | Are we obliged to give our right data to Google? | Technology | explainlikeimfive | {
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"> Are we obliged legally to give the right data to them? No. But they're also not obliged to allow you to continue to use their products/services if they find out that you've given them incorrect data."
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608dui | Why do car batteries only need to be charged when fully dead? | Technology | explainlikeimfive | {
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"text": [
"They are actually charged every time you drive. This happens with a machine called an alternator. When your car engine is running, it also turns a little electrical generator that helps keep the car battery charged.",
"Car batteries are kept charged by the alternator, which is turned by the engine. 12-volts DC is the nominal voltage of a car battery. If it falls about 10% below this, your car won't work. So the battery isn't completely dead when it doesn't work, it just isn't near 12-volts DC. This is true of even household batteries that you use in electronics. When they no longer work, they aren't completely void of any power, they're just not near their nominal rating for the device to work properly."
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609leu | How is international internet traffic separated and sent to the person who requests it? | If you visit a website where the server isn't in your country, it has to travel through the undersea communications cable. But if millions of people are doing the same thing, how are the individual signals separated? | Technology | explainlikeimfive | {
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"The internet is based on a system called [packet switching]( URL_0 ), specifically [TCP/IP]( URL_1 ). When sending data between two computers, this data is broken into packets, and each packet contains the IP address of the remote computer (and also of the sender's computer and other information, but that's not important right now). The IP address is used to route the packet to the correct computer."
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609w1l | How are the qualities of movies changed so seamlessly? (i.e a movie originally filmed in SD, then a DVD is released in HD) | Technology | explainlikeimfive | {
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"Most movies in the past were recorded on film, which is a very high quality medium. However what was released on VHS and other forms had to be lower quality due to the nature of those mediums. By going back to the high quality film they can make a HD version for modern mediums.",
"Up until the last decade, most movies were shot on actual photographic film, not via digital technology. Standard Definition (SD) and High Definition (HD) are _television_ standards. They describe the frame size, the scanning system (progressive or interlaced), and the frame rate for transmitting a signal for display on television. SD and HD are kind of meaningless when you're talking about actual _film_. For a good portion of the 20th century and into the 21st, movies were shot on 35mm film stock, which, for the most part, captures images at a frame size and a film speed that provides resolution suitable for display on HD television displays. That is, provided the digitized video made for playback over a TV signal is created from the actual film for HD playback. Frequently today you will see classic movies broadcast on TV in SD format (e.g. a 4:3 aspect ratio). That's *not* how those films were shot; rather at some point in the past _prior to the introduction of HD_, the films were converted to a video format (probably stored on tape, probably using a [pan-and-scan]( URL_0 ) method) and _that_ is what's being broadcast. Theoretically, someone could go back to the original film stock and create a new video for playback on TV at HD quality. Currently, as more movies are shot via digital cinematography instead of on actual analog photographic film, the definition at which they are captured matters more. I.e., if a movie was digitally shot at HD resolutions (1920 x 1080), then it couldn't be displayed on a 4K (UltraHD) display resolutions (3840 × 2160) without some sort of algorithmic upconverting to make it fit the higher resolution display."
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60as9y | What is the purpose and advantage of using prototypes in JavaScript rather than calling objects the classic way. | Javascript noobie here, I've been having quite a difficult time understanding the fundamental differences and what they mean between the classic way of calling objects and calling prototype objects. This has become a problem as i'm not always understanding code I read when it's "prototype oriented" Thanks | Technology | explainlikeimfive | {
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"It's not clear exactly what you mean, but I'm guessing you've seen someone call eg `Array.prototype.forEach.call(x, fun)` rather than just `x.forEach`. In that case, the Array prototype has a function attached called `forEach` taking one argument, an anonymous function. Within the prototype, *this* refers to the array itself, and `forEach` will say \"for each element in *this*, execute the function passed in.\" `call` is a method you can call on any function which lets you actually dictate what *this* should refer to within the function. Say `let a = [1, 2, 3]`. `a.forEach(console.log)` lets me log every element of `a`. `Array.prototype.forEach.call(a, console.log)` is exactly the same. But in the latter case, instead of `a`, I can pass in any array-like structure, even things that don't have `forEach` on their prototype,and it will work. For example, a NodeList or HTMLCollection. Open your console now and try `document.getElementsFromTagName('a').forEach(console.log)`. It won't work, HTMLCollections don't have `forEach`. Now try `Array.prototype.forEach.call(document.getElementsFromTagName('a'), console.log)`. `[].forEach.call` is briefer and works the same."
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60c1ef | When something claims to be water resistant up to 50 meters, what happens after 50 meters? | Technology | explainlikeimfive | {
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"text": [
"The pressure of the water at that point would overcome any sort of resistance. The deeper down you go... The more water pressure is experienced.",
"You also need to remember its pressure, if you slap the water really hard with your 30/50m water resistant phone or watch, you're likely hitting it with higher pressure than it can withstand and even though you didn't go 30m under water you can still break the seal."
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60dbgr | How is installing a program different from copying a file? Aren't they both just writing data but they work very differently? | Technology | explainlikeimfive | {
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"Think of it this way. You move, and you pack up all your stuff. Copying is just moving boxes to the new house. Actually installing is unpacking your stuff and putting it where it belongs",
"If the entire program is a single file, yes. Most programs these days aren't and require a substantial number of different libraries and files to be placed in specific locations for the main program to find. The installer takes those libraries and data files and writes them to the required locations."
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60dn9t | What is the difference between a muffler, a suppressor, and a silencer If there are only at all. | Technology | explainlikeimfive | {
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"text": [
"A muffler goes on your car. Both the Silencer and the Suppressor are two terms for the same device.",
"a silencer is a made up thing movies use. a suppressor is a real thing that actually makes a gun sort of quieter but not even remotely silent or even quiet. A muffler is a car part.",
"A suppressor and a silencer are the same thing. However, \"Suppressor\" is the accurate term. \"Silencer\" is the more commonly used term for people who don't know a lot about guns. It is also inaccurate, as they do not silence the gunshot. A bullet fires when a firing pin strikes the primer of the casing. This causes a small explosion inside the chamber which forces the bullet out of the end of the barrel. A suppressor basically collects this expanding gas and diverts it into a a metal cylinder at the end of the barrel. The result is a smaller flash and quiet*er* gunshot. It does *not* make the gun silent and stealthy. The soft \"*pfft*\" sound you hear in movies and video games is pure Hollywood fiction. A suppressor can quiet a gunshot to hearing safe levels, but it will still be very loud. A muffler is a car part. It's basically a suppressor for your exhaust pipe."
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60e3sh | Why do current FM radio station channels only range from ~80 - ~105? | Technology | explainlikeimfive | {
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"text": [
"That was the range assigned by various governments throughout the world for FM radio. Use of radio spectrum frequencies are regulated by the government. The reason being that if 2 people try to use the same frequency they could potentially interfere with one another. As a result various frequency ranges are assigned for different types of use. Some of the various ranges are AM radio, tv, wifi, cellular phone, etc. Since radio broadcasters are in a very stable physical location there is no need for a very wide range. For example if 106.1 in a city is permitted a 100 mile/160 km range, all you have to do is ensure that that frequency is assigned to another station with an overlapping range..",
"radio stations are in that band because that is what they are assigned. In order to avoid interference with TV signals. The FCC in the Us controls radio spectrum and makes sure there is enough space so signals are not being impeded. For example lower than 88.1 is the VHF TV channel 2-6 above 108 is channels 7-13. So it's all about spectrum management, companies pay big money to rent spectrum from the FCC who often auctions it off. The move to go digital tv over analog was to free up some spectrum. Lots of interesting stuff in this subject, A good place to learn more in radio is here URL_0",
"FM radio stations are described by their actual frequency, not by an invented channel numbering scheme like with wifi or analogue TV. The range from 87.5 MHz to 108 MHz is what's legally permitted for FM radio broadcasts."
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60f5e4 | Why were there black and white films still being made in the 60s? | Technology | explainlikeimfive | {
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"text": [
"Night of the Living Dead, which was released in 1968, was shot on black and white film for one very important reason; black and white film was cheaper.",
"It was cheaper. Not just the film stock itself, but also set design, props, costumes, and lighting. That, and familiarity with the process, are pretty much the only reasons."
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60ftnb | Why do so many sites have a selection of pre-made security questions, rather than allowing users to create their own? | Technology | explainlikeimfive | {
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"text": [
"It ensures that the security questions are of some level of difficulty. If they allowed users to define their own questions then some would be \"My password is hunter2.\"",
"Because people are idiots. People selecting security questions like \"write 'abc123'\" or \"what's my name\" or such would mean multiple people could have their accounts broken into, and undoing damage caused by their stupidity would by all likelihood be paid by the company, not the idiot user. So you remove ways for users to be idiots and thus improve security.",
"People can't remember the answers they gave. They certainly won't remember the questions. LPT: never answer those security questions accurately. Mother's maiden name? Please! Who can't find that info? I always make up answers to those questions so no one else could find the info or guess the answer.",
"As a UX designer, I HATE security questions. If you want a user to have 4 passwords, ask for 4 passwords (not advised). When I come across those, I always make the answer the last word of the question. My password is unique and secure enough.",
"New forgotten password questions: What type of pornography do you masturbate to most often? How many times has someone farted in your face? What was the first job you were fired from?",
"My answers to secret questions are usually something like n3NbYoy\\?2p7HUC}CSq/-x!2L;dx & S:z > \"%3Ar/ & 1},\\EC6u'nubh$Fw1qLs,cA. Every site asks the same questions, and you know that the answers aren't hashed/salted. If it's not safe to store a password in plaintext, what makes it ok to store the string used to short-circuit the password?",
"Another reason is to obfuscate the validity of a given username. Our bank login doesn't tell you whether you put in a valid username or not; invalid usernames just get random security questions / two factor authentication phone numbers, because we don't want people to trial-and-error their way into identifying an existing username.",
"My bank permits me to choose my own security question and answer for phone security. My question: _You're not going out dressed like that, are you_? The answer: _You can't tell me what to do! You're not my real father!_ There are a wide range of question/answer pairs like this that can be used to amuse even the most jaded bank customer service representative.",
"To piggy back off your question. I just would like them to include non open ended questions that can vary. \"What was your favorite movie as a child?\" A year or two from now I'm not going to remember what age I took as being a child, or what answer I put because who knows what movie I remembered then, compared to what movies I remember I watched now. I would prefer hard point questions. \"Your first car.\" or \"The house number to your longest stayed at childhood home.\""
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60fy5a | How can a single CPU core run multiple threads and how is that beneficial? | Technology | explainlikeimfive | {
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"The problem is that when people talk about this subject, they cut out so many technicalities that they miss the entire point (like other threads about the same subject in this sub). I'll try to cut as much of the technical stuff that I can. So think of it this way: a core has 2 parts. One deals with integer operations and one deals with floating point operations (decimal numbers). & nbsp; The first situation where 2 threads per core can help: **The integer part of the core is used, but not the floating point part.** That means that if conditions are right, the second thread is ready to be executed in the floating point part. However this _rarely_ happens, because data from a thread has to be executed serially, instruction by instruction. You cannot cherry pick floating point operations to perform, you will have to perform whatever comes next from the thread. This makes the likelihood of a floating point operation coming from one thread while an integer operation is coming from the other thread quite unlikely. Especially because these threads have differing priorities. As a result, this does not give a very good performance increase. The second situation: **The CPU core is stalled, doing nothing because of other bottlenecks.** One good example is when the CPU is waiting for the RAM to give it data. The CPU has a very fast memory, called cache memory. When an instruction comes the core searches for the necessary data in cache. If it doesn't find the data, it asks the RAM for the data. RAM is very slow compared to cache, so the core is just waiting for the RAM to return with the data it needs. During this waiting period the core can execute the second thread, thus negating the performance penalty. & nbsp; So practically simultaneous multithreading makes the processor work closer to 100% over a given period of time. Without a second thread the processor has more 'breaks' between its operations. Do note that these breaks happen extremely fast and you can't see them in task manager's CPU usage for example. It's a very complicated piece of tech and I've only scratched the general idea. There's _a lot_ more to explain, like other types of core stalls, but I think that's more than just the general idea. I hope my answer was clear enough. If you have any questions ask.",
"Single CPU core running a single thread can be idle very often. It can wait for user interaction, wait for data from network, wait for data from disk etc. Switching this core to different task incurs small penalty (so called contex switch, that is saving state of CPU to memory, and restoring from memory to CPU state relevant of other task). But allows to perform calculations needed for other task while waiting. Hyperthreading means that single CPU core has internal space to store additional state internally, so context switch penalty for switching to that task is much smaller."
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60fz5v | Why do cars use a visual measurement for the engine's temperature rather than degrees? | Technology | explainlikeimfive | {
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"This is a classic example of good instrumentation design. Must people don't know what a \"good\" temperature is, so showing the actual number requires them to learn and think more. A gauge that reflects meaningful analysis like cold, normal, hot, and \"too hot\" is actually more useful to most operators.",
"The average person doesn't know what their vehicles coolant temperature should be at, especially under certain conditions. By using a basic high/low visual, many more people can understand many more gauges. People are used to reading a gas gauge, which is a basic high/low gauge. That means they can also read any other gauge using the same principle. After seeing every gauge for a while, a person knows how each one should be. If it's outside of the norm, there's an issue. Now, that last statement. Knowing what goes where to identify a problem. You *could* just tack on numbers to these gauges. But when you start switching vehicles, now you get a cause for concern. Example A: voltage If I go drive my 4.7L by dodge, I know I charge about 14.5v. Now if I go hop into a 6.0 powerstroke and see it charges at ~13.5, sometimes lower, I'd be concerned. But these dummy gauges show the needle in the middle, so I know it's in the ok range. Example B: Coolant temp I drove a 2.5L by Chevy for a while, about 8 months. The little thing runs at 190* I moved up to my 4.7L, and it runs 210 perfectly. If I was not very smart and only saw a digital display while making that change from one vehicle to the next, I'd be concerned about my new - to - me vehicle is about to overheat. But the gauge is right in the middle, so we are ok.",
"My car has both, a colour gauge and a temperature rating. I think its because most people don't know what temperature their engine is meant to be at, but they do know that a dial constsntly in the red is worth getting looked at."
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60g01q | How computers handles large numbers. | So I was sitting in front of my laptop yesterday when I decided to test the calculator. I realised something I've never thought about before. How can my 64 bit system handle numbers larger than 2^64 ? The calculator can calculate 3248! which is roughly equal to 1.97×10^9997 . | Technology | explainlikeimfive | {
"a_id": [
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"There are two ways. Your calculator likely uses [floating point arithmetic]( URL_0 ). Instead of holding the number as-is, it holds two numbers - the mantissa (m) and the exponent (e) - which represent the number m\\*2^(e) (and one extra bit is used for the plus/minus sign). The number 2^64 is can then be represented using m=1 and e=64. It is also possible to represent large numbers in software with an array of numbers. Just like we can represent number of any size using a series of digits, you can for example represent 64 bits with two 32-bit numbers - the 1st number represents the higher order bits and the 2nd number represents the lower order bits. This makes the arithmetic a bit complicated of course - when you add two numbers, first you add the lower order bits, figure out what the carry would be, and then add the higher order bits along with the carry. You can use the same method to represent number of any size (96 bits are three 32-bit numbers, and so on)."
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60g4jf | What happens with excess electricity from a generator? | Before anything else gets said, I'm asking on a single generator level, not a full domestic power grid. As in, the kind of generator you might bring on a camping trip for whatever reason. What happens if there's too much electricity being generated? Say like you have a gen that's putting out enough electricity to power a whole house, but is only hooked up to a single lightbulb. What then? | Technology | explainlikeimfive | {
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"If there really was excess electricity because the motor speed was too high, the voltage would rise. Voltage fluctuation is acceptable within certain limits, but past a certain point it could damage the devices attached to it. Generators you can buy have regulators to prevent this from happening - see [here] ( URL_0 ) for an explanation with diagrams. Short version: a control circuit sends a DC voltage to a rotor coil, which actively slows the motor down as needed to maintain the correct voltage."
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60gpk6 | How does white hat hacking work? | Technology | explainlikeimfive | {
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"text": [
"It's the same as any hacking, it's just done with the express permission of the system's owner. You can hack your own computers, for example, all you want. EDIT: Typically white-hat resolves to reporting problems to the owner, helping them harden their systems against those attacks, and reporting flaws exploited to the software vendors.",
"White hat hacking is done with the owner's express permission, with the intention of helping the owner find, identify and plug loopholes in security. In contrast, black hat hacking is malicious and done without permission."
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60gq2y | I've seen this more and more, but why do people put their cell phones on speaker and then hold the phone an inch from their mouth? | I was out and about yesterday, and saw several people with their cells on speaker. Passerby could hear every word of the conversation. But they were walking down the street, and putting the cell phone mic directly in front of their lips for the entire conversation (or at least several minutes). When I first saw some people doing this, I thought it was because their cell was malfunctioning in some way, but I'm seeing it more and more over these past few months. Is this some sort of pop culture trend I'm unaware of, or is there a logical explanation? | Technology | explainlikeimfive | {
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"I don't know about men that do this, but women do it so you don't end up with a phone covered in make-up and hair products. Also, depending of your earrings, you can get a clanking sound when your earrings hit the phone. Source: my wife.",
"I think in some cases the earpiece isn't loud enough in some environments, even at full volume, whereas the speaker is quite a bit louder.",
"As far as I'm aware, they are using the speaker so they can hear it without putting it up to their ear, but want to make sure they are heard. Kind of pointless imo."
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60ho0h | net neutrality | Technology | explainlikeimfive | {
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"Let's say you get your TV and your internet from Comcast. Comcast owns the lines (with government oversight) that run from their hubs to your home. Comcast sees that you use a lot of your internet bandwidth to do things that compete with their TV service (like Youtube Red, Hulu, Netflix). Instead of keeping your $100 per month TV service with them, you might just want to up your internet by 25Mbps for $20 extra per month. Right now, if you go to reddit or if you go to netflix, you access them both equally. You are getting data at the speed of 25 Mbps from either of them (reddit doesn't put out that much data, just using it as an example). Comcast wants to be able to pick and choose internet traffic and shut it off, or make it almost zero unless you or Netflix pays them more money (or just block access altogether). If there is no net neutrality, they can do that. Net Neutrality says all internet traffic is equal, and if a person is paying for internet, they should not be censored as to what they can access.",
"Imagine there is a street with a millionnaire on it, and a poor guy. The poor guy wants to download pictures of kittens. The millionnaire wants to download spreadsheets. The person sending the stuff doesn't care which he sends first but he can only send one at a time. So firstly he goes to the millionaire and says 'If you give me $5, I'll send you your stuff first' if there's ever a queue. but for this example, the millionaire says 'nope'. Secondly they go to the person providing the spreadsheets and say 'Unless you give us $10,000 a month, we'll going to always put your spreadsheet behind all these damn kitten pictures we're sending out, so people will think your site is slow and shite, and you'll be out of business before you know it'. Think a kind of blackmail. So the spreadsheet business gives them money to not slow them up, and the poor guy looking for the kittens gets his cute pictures last - always - from a cat site that is now suddenly slow and shite, unless the kitten picture provider is prepared to cough up $11,000 to beat the other dude.. and it all gets a bit horrible for all involved apart from for the ISP who get loads more money in by playing sites off each other (sites will quickly start bidding for speed of content delivery - those that can't afford to bid .. er .. you're bang out of luck mate, and probably bang out of business). Net neutrality says 'Send it all equally using a queuing system, no matter who cuts you a damn cheque, as it's altogether fairest'."
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60hpsh | What "Run as administrator" does to a software? | I've encountered many problems with software (not starting, freezing, crashing, poor performance etc.) that were fixed by simply running the program as administrator. What actually changes when doing it? | Technology | explainlikeimfive | {
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"Software runs on top of the operating system. Normally the software should not be altering the operating system that it's running on. Back in the 90s and early 2000s there were LOTS of problems with windows and viruses, mainly because Windows allowed any software to alter itself to whatever needs the software had. Virus makers took advantage of that. But also many legitimate programs did it because it was easy and it allowed them to do things not originally intended by the OS programmers. Come later versions of windows, Microsoft decided enough was enough and no longer allowed software to run as administrator by default. Not running as administrator forbids the software to make changes to the underlying structure of the operating system (I think this first happened in windows vista). So now, software did not run with administrator privileges. This was all well and good. It took some time but most software makers updated their programs so that they did not require administrator privileges to run. So what's happening to you is that the software you are trying to run has a legitimate reason to change the OS, or the programmers were lazy and never updated it from the older ways of doing business, or the software is infected with a virus. My personal rule is that if software requires administrator privileges to run, it's likely a good idea to just not run that software."
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60i0mn | How can we communicate instantly around the world via cellphone, however when news broadcasters communicate on TV there is always a delay? | Technology | explainlikeimfive | {
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"text": [
"Probably has to do with cell towers vs satellites... I mean no matter what you're trying to do with a satellite there will be a large delay of about .6 seconds at least in certain areas"
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60jrcg | How do phones make themselves vibrate? | Technology | explainlikeimfive | {
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"They have a small, off-centred weight that spins. Because it's off-centered, it's unbalanced and causes the vibration when it spins.",
"They have a little motor in them with an unbalanced weight. Spin it really fast and the motor+weight shakes the phone."
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60k092 | What is happening to your computer when it goes to sleep? | How much functionality does it lose/retain when it cuts power usage? | Technology | explainlikeimfive | {
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"The simplest analogy is that sleep mode is a pause button for whatever the state is of the computer. In sleep mode, power is still running to the memory to maintain its content. For background info, ram memory needs power to constantly refresh itself in order to retain its contents. This is the trade off of its extremely high speed. A lower speed memory device such as a jump drive or a solid state hard drive stores data without constant refresh so power is not needed. So back to sleep mode, basically the memory contents are suspended as described above and the cpu stops performing work and essentially turns itself off. The chipset of the motherboard coordinates all the steps necessary to get the cpu and memory and other computer components in a sleep state and is responsible for waking things up when something takes place (e.g. pressing the power button again or opening the screen on a laptop or wiggling the mouse). Sleep mode is different than hibernation in which the memory contents are copied to the your hard drive before the cpu shuts off. So hibernation makes your computer state safe from unexpected power outage which would cause memory contents to be lost if the computer was in sleep mode (without power, memory cannot maintain its state and the data is lost immediately)."
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60klhh | Why does a webpage jump around on its own if I am scrolling through it and it is still loading? Shouldn't it recognize that I am scrolling and not jump to where it wants to go? | Technology | explainlikeimfive | {
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"A \"feature\" known as reflow. It's present in a lot of major web browsers. When the HTML of a page changes (not limited to but is the biggest culprit), it triggers a reflow. The web browser recalculates how it should display and by default it will bring the page back to the top. So you're looking at a Web page reading all of the good content whilst a large image or ad is slowly loading in the background. You get half way through the article and the image finishes loading. It gets rendered on the page.. BAM.. reflow.. you're now back at the top of the page dazed and confused. Rage sets in. Phone gets launched into the nearest wall. You never find out the 10 things that will truly make you happy in life. And the cycle continues.",
"Depends on the web page, but it's likely jumping because it's still loading all of the images and other things on the page, which might push the text down and cause it to \"jump\"."
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60l9wt | How does computer hardware control software? | I am wondering how software controls hardware. How does what I type on the screen translate to an electrical signal that makes physical things move. For example, how does me right clicking in the dvd drive icon and ejecting actually make the dvd tray open? | Technology | explainlikeimfive | {
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"Everything happens through the memory chips. Memory chips are banks of transistors and capacitors that can hold a voltage (+5 volts for example) that is interpreted as \"1\", or 0 voltage interpreted as \"0\". The CPU processor works on memory; it grabs, basically, one number at a time, changes it, then puts it back in memory. The video works on memory too, the image on your screen is actually fully built inside the video card's memory, with rows of voltages representing the colors of each pixel. The DVD drive also has access to a very small amount of internal memory, and it's connected to the circuits that give power to the motors inside the drive. The job of an operating system like Windows is to interpret the commands (voltages) that come from the mouse and keyboard, and to display (send voltages to the video card) the results for you in a visual way that you can understand. Also, if your commands are for a subcomponent of the computer, Windows will call up the driver software for that subcomponent, so it can do more interpretation of your commands. The driver software basically interprets your commands in terms of stopping the spin motor, parking the laser head, and then activating the eject motor inside the drive. Then the smaller memory chips inside the drive itself are given 1's and 0's (voltages) for the required durations for each motor, and the motor circuitry is activated by these voltages."
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60m47b | Why are my old smartphones (2013) so slow today doing simple stuff like photos and internet browsing when it could run Playstation 3 graphics games with ease? | Technology | explainlikeimfive | {
"a_id": [
"df7hyt2"
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"text": [
"Planned Obsolescence. URL_0 Basically, if you make the perfect product, then people would not need to replace or buy a new version. However, if you ensure that your product degrades over time, then you'll force your customers to make repeat purchases."
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60n2at | I've never heard 8 Track. What am I missing? | Technology | explainlikeimfive | {
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"text": [
"Nothing. They used the same media as cassette tapes but they had a method of skipping to the next track that you just can't do with a cassette, but they were much larger so less portable."
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60ofsm | How can internet speeds be 1GB+ when computer's write speed is no where close to that? | Technology | explainlikeimfive | {
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"text": [
"1. You're conflating mega/giga BITS with mega/giga BYTES. 1 GigaBIT (if you had a gigabit connection) is 125 megaBYTES. 7200RPM hard drives can get 70-90MB/s so even without a SSD you'll get pretty close. SSDs can get ridiculously fast, even consumer ones. Example: Intel 750 series drives can get a sequential write speed of up to 1200MB/s, or 9.6Gigabits/second. 2. Not everything is always downloaded to disk as opposed to RAM, and nobody's going out and buying a 10 gigabit internet connection for their home.",
"A lot of different numbers being thrown out there, but... Your computer doesn't send data over the internet from the hard drive, it sends data that is stored in RAM (or in the CPU cache) DDR3 RAM has a potential transfer speed of 6400 MB/s, or roughly 49 Gbps When you talk about internet speeds, though, you're not just talking about the data throughput, you also are looking at the TCP or UDP header (which is handled by the software, and contains the IP address) the Ethernet packet header(which is handled by the network card, and contains the MAC address). Granted, it's not a lot, but it's 38 bytes of Ethernet header for every 46-1500 bytes of payload (there's also jumbo frames, but lets not go deeper down that rabbit hole) So, already, your computer can potentially be sending 50 times 1Gbps just on the strength of the RAM read write speed (plus Ethernet headers), but there's another factor to consider: there could be more computers on the network than just yours, and all of them potentially could be using the available bandwidth. And if you're wondering how switches handle all this? The ones that are capable of switching and routing those levels of throughput use far more advanced (and expensive) hardware than what is found in consumer electronics, and also that is specialized to the task of moving data quickly between network ports- more than capable of surpassing any of the speeds discussed here by leaps and bounds.",
"People have given some decent answers, but also keep in mind that Gig internet speeds for consumers are typically meant to be shared among many devices. Most people have 2-3 connected devices at any given time. I know between myself and my wife we each have cell phones, laptops, desktops, tablets, smart TVs/blu ray players, internet connected home devices, a backup server, media PC, etc.",
"Because write speed refers to disc (hard drive) access and writing/reading from disc. When you are utilizing the internet things are going to memory (RAM) not disc and memory is significantly faster than hard drive operations."
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60pirb | Why does turning the wifi router on and off again solve most problems with the connectivity? | Technology | explainlikeimfive | {
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"text": [
"The same reason it works for a lot of technology. When you power on your router it loads its base firmware and your configuration from nonvolatile memory into volatile memory. This load represents the router in its perfect state. Then it goes to work. Inevitably on a long enough time line with enough work going on, the router will make little mistakes and develops errors/imperfections in its running config, and you'll see problems. A reboot wipes out this erroneous software, and reloads the perfect state back from nonvolatile memory.",
"Imagine you were doing carpentry in your shop for weeks and weeks without cleaning up. Your tools would be scattered and you'd have wood chips and sawdust everywhere. It would get so bad that at some point you couldn't work anymore. Your router is working too, and as it works little errors build up like in my example."
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60qjzv | When resetting an electronic device (modem, cable box, cell phone, etc.) why do instructions say to wait 10-30 seconds after unplugging/turning off? Once the device no longer has power, does it really register the passage of time? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Lots of electronic devices have capacitors, which store a little bit of energy. It usually takes 10 seconds to empty all of these capacitors to fully turn off your device. 30 seconds is really just a generous amount to be almost certain.",
"Temporary settings and data are often stored in RAM, which requires power to function. But it doesn't clear out immediately once turned off, it dissipates over the course of a few seconds, depending on a few factors, like the temperature. The idea behind giving the instruction to wait is for there to be a truly \"cold boot\" of the machine. In the great majority of cases it makes no difference. But when you don't even know what the problem is, including a harmless troubleshooting rule that can solve some strange edge cases can be a good idea.",
"To demonstrate why, find a laptop power brick or something similar with a power light on it, and unplug it from the mains. The power light will probably stay on for a few seconds while the residual energy in the power supply discharges. My laptop charger's light stays on for a good 10 seconds after I unplug it."
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60qo8o | Why are most smartphone touchscreens made out of glass instead of plastic? | Technology | explainlikeimfive | {
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"text": [
"Even though plastic screens don't crack and cost less, glass screens are more durable in the end. Glass cracks sure, but they don't get scratched as much, which is mostly what happens. Most phones are scratched more often than cracked so it's better in the long run. Think if you had to put your phone in the same pocket with coins and keys like some people do, you would get it scratched every time you put it in your pocket if you had a plastic screen. Also, glass screens are better for touchscreen devices since it makes it easier to register touches by the sensors. I watch a lot of phone scratch test videos and most smartphones with a glass screen will scratch at a Lv 6-7 on mohs hardness scale while plastic screens scratch at a Lv 3. Think about the new Nintendo Switch. It has a plastic screen because Nintendo thinks that you will have it kept tidy, and you won't have it in your pocket damaging the screen.",
"It's a trade off - glass is much easier to break but is also much more scratch resistant. If you had a plastic screen, it would be covered in micro-scratches very quickly from the normal abuse that a phone takes. Dropping your phone and having the glass break does happen, but at nowhere near the regularity as the scratching would.",
"Some phones do have plastic touchscreens. But they are much less scratch resistant and less stain resistant. So over time you have a blurry screen since its so scuffed up and it can get stains from food on your hands or even your sweat. While it less likely to shatter, it looks much worse despite not shattering. Most people find the plastic screen has a worse sensation for using the touchscreen as well."
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60qu7o | What is a patent? | Technology | explainlikeimfive | {
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"Basically, if you invent something the government gives you temporary exclusive rights to produce that thing, in exchange for telling the public exactly how it works. Basically, they exist to promote innovation. Inventors are motivated by the prospect of having a monopoly on their product (and not having their idea stolen by someone else) and future inventors can improve upon the designs that are now public information."
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60r767 | Why is there not a "make things cold quickly" counterpart to a microwave? | Technology | explainlikeimfive | {
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"There's a thing called an [*anti-griddle*]( URL_0 ), but that's more of an opposite to a cooking range than a microwave."
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60s3vk | How does audio get transmitted over a specific frequency or waves? (AKA Radio) | As in, how do we make audio (or even visual) data travel in a wave of light at a certain specific frequency? I don't know if anyone gets what I'm trying to get at. | Technology | explainlikeimfive | {
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"Radio waves have two ways of being transmitted: AM (Amplitude Modulation) and FM (Frequency Modulation). The way a radio wave is created is by electrons running up and down radio towers. This is what creates the electromagnetic wave. (Think of it like holding the end of a rope, and moving your hand up and down will send waves down the length of the rope.) Electromagnetic waves have a special property because it creates an electric field in one direction, and a magnetic field in the perpendicular direction. This is very handy, because these two fields actually reinforce each other, meaning unlike the rope in the analogy, it will actually be able to continue through the air for huge distances. FM radio means the frequency of the wave is changed to create the data being sent. This means that when creating the wave, the electron moves up and down the same amount every time, it just varies how fast it moves. AM radio means that the electron moves at a constant speed, but the height it goes up and down the tower is varied. This actually is why AM is often a much weaker signal, because changing the amplitude at times makes the signal much smaller, while FM radio is consistently the same strength. So to answer your question - the way the frequency is determined is simply how fast this electron moves. The exact same audio signal can be sent in different frequencies because while the way the electron moves to create the data may be the same, the actual relative speed in which in moves (or the frequency in which it moves) determines what radio channel you need to tune into to receive the signal. Also interesting to note is when you tune into your radio you see the channel represented as kHz, MHz or GHz. This means kila-hertz, mega-hertz and giga-hertz. A hertz quite simply is how many cycles per second is being created by the signal. So if you tune into 91.5 Mhz (FM), you are tuning into the radio frequency that oscillates at 91.5 million hertz per second, where the signal is created through frequency modulation :)"
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60sbfh | How are bugs created in programs? | To my understanding, they always work as long as everything is in place as long as I don't miss a punctuation or of the sort. So of everything is correct how/why are they made? Edit: I'm asking from my own experience when I was in high school/college and took a couple basic programming classes, and I've always been interested in it but it wasn't my forte. I'm also an avid gamer and witnessing bugs and seeing people complain about bugs in video games. I get that not everything can be tested, but depending on your own field of programming what is tested before the final product is sent out? | Technology | explainlikeimfive | {
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"Because humans miss things. If I were to say, ask you to go build a house, how well would you do? I'm sure you considered wall placement and stair placement; but did you remember electrical or plumbing? What about hookups for water/gas/sewer? Any space for your septic field? Well, whenever a development team is told \"go make this\" it is a very similar process. They sit down and discuss all the things they need to consider and as they start to implement they think of more and go back to the drawing board. Eventually, they think they are done and the ship the product to the customer. And they miss stuff. Always. What they miss may vary from the wild corner case no one thought of (like hook up for solar panels) to the \"how the hell, you must have not even tested this because there is no front door\". Source: am software developer",
"People do miss punctuation marks or say < instead of < = or a million other things and then things don't work correctly. Their is generally no way to know everything is or isn't correct until it breaks."
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60sf4e | New to online gaming, what are ping and latency and how does it impact my gaming experience? | Technology | explainlikeimfive | {
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"Ping is how long it takes information from the host to reach your computer. You always want the lowest ping possible. Anything over 100 can start to really disrupt gameplay.",
"When you ping a server (in this instance a gaming server) your computer simply sends out a signal and if the server is there it will respond and that round trip is your \"ping\". This is measured, hopefully in milliseconds. Latency is a step up from ping and attempts to capture \"quality of connection\". Its basically saying when i send an input to the server, how long does it take for me to get a correct output. In network connections there is A LOT happening which may result in dropped packets, multiple messages passing back and forth to ensure both parties are on the same page etc. Latency measures the quality of the communication between the two. Lag is a result of high latency."
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60skwj | Why is it when you translate a phrase through Google Translate from A to B and back to A, that the first A and the second A are not identical? | I was thinking about how I've been browsing /r/unexpected today, which has become a German speaking sub (rather unexpected, wouldn't you say?), and Google Chrome automatically translated the sub to English for me. I figure most of the English speaking posters in that sub used Google Translate today to post in German. Sometimes, the translation back to English is just weird enough to clue me into the inadequacies of Google Translate. Leading to my post here. As far as I know, when I enter in English phrases, I'm using proper English (syntax, tense, conjugations, etc), and I can only trust that Google gives me back an accurate translation. It's when you flip it back that you can tell something got lost. How does that happen? Does it happen with every language? Can language software ever be perfect, especially with most languages filtered through Google being living, changing languages? | Technology | explainlikeimfive | {
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"Because language structures differ too much. Context, syntax, etc. make things too complicated. Modern translators do not use syntactic rules or anything. They use statistical models to try to infer translations based on maximum likelihood. (In easy terms, it obtains the list of words that are more likely to mean the same). How do they achieve this? Well they get trained with thousands of millions of 1-1 translations (e.g. Court transcripts in multi lingual countries) and then they Build these models to calculate likelihoods. Now as of why we can't translate from a to b and back to a giving the original phrase: This is because of language structure and the fact that we are using these probabilistic systems instead of actual mappings. Example I like apples A mí me gustan las manzanas Two identical phrases, In two different languages. The English one has 3 words, the Spanish one has 6. This means that (of course, making things super simple) a. For every English word, there can be more than one correspondence in Spanish. Or b. There are invisible words in the English version but which are needed for context in the other language. In this case, I = mi, like = me gusta, apples = manzanas. \"Me gusta\" meets scenario (a) and the words \"a\" and \"las\" meet scenario (b) This means that translating things will be tricky, statistically a translation like \"Apples are liked by me\" could be provided because of how the models were setup. It is important to mention that we COULD get the original phrase, but this will not always occur because the ORIGINAL PHRASE can have a lower probability in the B to A distribution. ---- Edit: Check URL_0 This finds a translation equilibrium using Google Translate from English to Japanese. It re-translates translations until we find a scenario where translation from A- > B and B- > A correspond to each other. A good example is this guy: URL_0 i-cannot-believe-this-sentence-reaches-equilibrium-12933403",
"Because language is complicated and while you may be using perfect grammar there is still ambiguity in almost all languages. Like the sentence \"Dutch military plane carrying bodies from Malaysia Airlines Flight 17 crash lands in Eindhoven.\" You might read that as: \"Dutch military plane, carrying bodies from Malaysia Airlines Flight 17, crash lands in Eindhoven.\" or: \"Dutch military plane, carrying bodies from Malaysia Airlines Flight 17 crash, lands in Eindhoven.\" The in the first example, the Dutch military plane crash landed while in the second example the Dutch military plane landed safely. Computers are really bad at figuring out what you mean and different languages have different ways of expressing meaning. There will never be a day where translations are picture perfect until we have AIs that can understand context as well as humans or better!"
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60sp30 | Why where Semi Conductors a revolutionary discovery for electronics and computers? | I know the properties of a semi conductor but I think I'm not aware of why they are so important | Technology | explainlikeimfive | {
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"Semiconductors when they were developed solved several critical issues with computers at the time. 1) It made parts small. Before semiconductors, you'd have vacuum tubes and large apparatuses like punch cards or physically woven copper wire as a medium to store information. Semiconductors took the same functions and shrunk them down to tiny proportions. 2) It introduced the ability to make affordable parts out of common materials such as the printed silicone chip. 3) It reduced the overall heat output, requiring less energy and therefore even smaller computers to hold the same information. 4) It introduced programmable logic circuits. Before, computers were only capable of exactly what you put into it. It was a giant 1 way logic circuit. Think of a calculator. If the user puts in Function A, calculation inputs 1, 2 ... n and process F(A) and output the result. Programmable logic boards allowed for MANY of these processes to not only be automated, but scaled down to 1 or 2 parts instead of chains upon chains of storage required before. These are some of the simple reasons why semiconductors are revolutionary, and by looking up the WIKI you'll learn much more about the history of semiconductors."
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60tj0a | Why are bicycles so much more popular than tricycles? | I have been working on a project to evaluate different types of practical personal transport in a modern city. I have never ridden a tricycle, but seems to me that at least on paper an electric-powered tricycle (such as [this one]( URL_0 )) is a much better alternative to electric-powered bicycles. There's no need to balance on tricycles and they can carry bigger and heavier loads. This make tricycles very useful especially for workers and the elderly. They are also better than bikes for zipping to the nearby grocery store and back. The only negative I can see is that tricycles may not be as foldable as a bicycle, which makes them more of a hassle to carry onto a transit train. So why do are bicycles so much more popular than tricycles? Is there a practical reason why bikes superior to trikes? | Technology | explainlikeimfive | {
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"bikes are faster, handle better, and cheaper; in a generality. They are also easier to store. Bikes are available with multiple gears, which would be much more complex on a trike.",
"I'm sure a large part is the stigma associated with tricycles. You ride tricycles as a kid before you learn to balance a bike. If you ride a trike, people will think you're doing it because you *can't* ride a bike. People are afraid of being judged, so they ride bikes, even if a trike is a better choice on paper. Also, bikes are smaller and easier to store, which is preferable. They can carry the same load as a trike, you just have to balance."
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60vuy0 | How do radio waves transmit data | I am trying to understand how wireless radio waves send information and how electronic devices can understand what they mean and decipher them into something meaningful. How does a wave mean different numbers and letters and sometimes even pictures or video? | Technology | explainlikeimfive | {
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"Okay, this is very basic, mind you. Imagine a radio wave is like a squiggly line, completely even on both sides, so you have even \"peaks\" and \"troughs\" (hills and valleys). Now imagine that by changing the power we put into transmitting this, we can change how high or how low these peaks and troughs are. This gives us the ability to define our zeroes and ones. Which leads us to binary... Binary is the basic building block of our digital world. Imagine it's a bit like lego, you have a couple of basic bricks, but you can build all sorts of things from that. Digital transmissions are the same. We use various predefined formats (everyone has to know what a house looks like to recognise a lego house) made up out of *reaaaalllly* long strings of 1s and 0s, and call that a JPEG (picture). We can take even longer strings and call that an mp4 (video) file. In reality it's a bit more complicated than that at the 1s and 0s level, because we've made things easier for people by building in various translation layers. Going back to lego, if you know you're always sticking two bricks together, you may as well have them pre-made as a larger block, because it makes it quicker for you to build your house. We do the same with our 1s and 0s. Using only bigger blocks has some downsides, as we sometimes then have empty space or use more blocks than we need to, but since it's quicker we don't really mind. This is repeated a couple of times, until we have formats within formats; a lego house set might come pre-packaged with walls and a roof. This wouldn't be very useful if you were building a lego boat. So we use the writing on the package to tell you what's inside. But at the end of the day, it's all made up of those really basic 1s and 0s."
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60wlpa | Why does some antivirus protection software (Norton, McAfee, etc.) make your computer run worse than it did before? | Technology | explainlikeimfive | {
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"Think of it this way. Let's say that you're a company that receives a lot of postal mail. You could have the mailroom receive that mail, then take it directly to the recipient. That's your computer without antivirus. Alternatively, your company could have a room directly next to the mail room. The mail room receives a letter and gives it to the people working in that room. They open each and every letter and look for the contents of that letter in an old-fashioned 30-volume encyclopedia. If they find it in the encyclopedia, they throw it away. If they don't, then they put it back in the envelope, send it back to the mailroom and the mailroom then takes it to the recipient. That's your computer with antivirus. Antivirus slows your computer down because that's what it's doing constantly poking at what's going on inside your computer and asking \"is that a virus? No. Ok go ahead.\" Now, it's a computer program, so it's pretty fast at the encyclopedia search, and it has ways to speed it up. But, still that takes time. And, that's why your computer is slow. For that reason, it's still true that if you want to download and install a large software package (especially an uncommon package), turning off the antivirus can speed up that process dramatically because it removes the \"let's check the encyclopedia\" check.",
"Your antivirus is like a bodyguard. If i have a car I can transport that extra person with me with little problem. If all i have is a bicycle then i will really struggle to support him. Your computer might be a bicycle more than it is a car.",
"Cybersecurity Engineer here. The best ELI5 answer I can provide to you is this: There's a thing inside your computer called a hard disk drive, and it's where all the stuff that you have on your computer is stored. Getting stuff in and out of the hard drive is a bit like turning on a tap of water in your house - the water can only come out as fast as the tap will let it. Now, the antivirus software is looking for bad software on your computer, and now and then it starts something called a scan, which is where it looks through all the stuff on your hard disk drive and checks whether or not it is bad or good. The trouble is, the people who make the antivirus software aren't as smart as they think they are, and after lots of years they still haven't figured out how to do one of these scans without using up all the room on the tap. TL/DR - antivirus software consumes too much disk I/O on your computer because AV software engineers don't seem to realise that you're trying to use your computer while they scan for malware.",
"OP is asking why *some* antivirus software makes your computer run worse (compared to others). He even mentions a few notorious brands. He isn't asking how an antivirus works, or the general performance impact. He is asking about the difference between average and bad.",
"Two reasons: 1. the job of antivirus software is to detect viruses. it is not to make your computer run faster. So they don't care about how much they slow down your computer. And in order to detect viruses, the AV software has to do a lot of work. Everything you send and receive over the network has to be scanned. Every byte you read or write to or from your harddrive must be scanned. It installs special drivers which get a sneak peek at *everything* your computer does, and that adds up to a lot of overhead. 2. Antivirus software is generally crap. Don't use it. Serious security experts generally recommend using no antivirus, or using the one that comes with Windows (Microsoft Security Essentials), which is basically the only one that won't actively endanger you. \\#2 might be surprising, but the thing is that because AV software tries to be everywhere and see everything that goes on, and has full rights to mess with anything, that also makes it an attack vector: if you can hack the AV software, you've got control of a tool that already has access to *everything* that goes on on the computer. That means it can make you *more* vulnerable. And most antivirus software is shockingly insecure, so using it will typically leave you with a slower computer *and* make you more vulnerable to attacks than you were otherwise. Install updates frequently, use a firewall, don't click on suspicious links, and delete your antivirus software. That's how you keep your PC safe.",
"Antivirus is difficult. It requires a lot of resources and access to attempt to secure your computer. This resource consumption can have severe performance impacts on how well the computer runs.",
"Technically each active background process would make your computer a little slower. Antiviruses do a lot of things on the background. For starters, they scan each file, local or remote, touched by your system. Scanning by itself is a complex procedure, as modern viruses employ encryption and other stealth methods to avoid detection. Also, most antiviruses also monitor the data flowing through your network interfaces which is even more taxing. External devices are yet another vector of viruses and also demand heavy monitoring. The antivirus itself might also be a target of tampering, so it has to counter against that too.",
"Here's John McAfee answering some questions about his software. URL_0",
"I like the mailroom analogy but to answer the actually question of the post, I'll put it like this. Bad antivirus software (norton, mcafee, etc...) have the mail room 5 buildings down and up 30 flights of stairs. Mail delivery is inefficient and time consuming. \"Good\" antivirus solutions have the mail room directly next door. It's more efficient and isn't bogging down the mail delivery process with inefficiencies"
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60xe1s | How is LastPass secure and not the weakest link to ALL my passwords? | Especially when you consider that many non-corporate PCs are probably not as secure themselves and the users and their setups don't always follow best practices for security, connecting to WiFi without a VPN, correctly securing their home router, etc. | Technology | explainlikeimfive | {
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"It's both. LastPass, and password vaults like it, are the weakest link to all your passwords in that if anyone gets the password to the vault, they have access to every password stored therein (or at least, all passwords stored up until you next change your vault-password, and afterwards they only get to keep any if they had the good sense to store an old copy of the vault. This is plenty bad enough to be a concern). On the other hand, without that password they'd need an absurdly powerful computer to get into the vault. Given that (after a cursory bit of research) LastPass uses 256-bit AES, even the governments of major world powers don't have the kind of processing power necessary - *as long as* the master-password isn't something easily guessable. And they *won't* have that kind of power for many years yet. AES is a *good scheme*. Since the vault is encrypted locally, rather than server-side, you only need to worry about the security of the computers on which you access it, not the networks to which they are connected. Any attempt to man-in-the-middle attack the vault directly is going to give you nonsense rather than your passwords, so you have two things to concern yourself with. Fake software is one - either a fake LastPass plugin that captures the password in plaintext or, for the web interface, a fake CA certificate that allows MITM-ing the page and inserting code to retain and forward the master password. The other is keylogging, which is one reason they provide methods for 2-factor authentication and an on-screen keyboard that bypasses the OS's usual text-entry methods. In general, the people who use such vaults (and I include self-hosted or network-feature-free ones like the KeePass family, by the way) have concluded that the security gains of having no duplicate passwords outweigh the single point of failure introduced by storing them in a password-vault, at least given how relatively difficult it is to get the password for said vault, which is to say at least as difficult as getting any other unique password and probably more so.",
"Your LastPass vault is encrypted, and it only ever gets decrypted locally, on your own machine. This means that someone breaking into LastPass's database isn't a concern, and nor is someone intercepting your network traffic. So your home router, insecure Wi-Fi, etc are not worries. Your only worry is your local machine. Then the natural question is: regardless of encryption, isn't locking all my passwords behind *one* password stupid? If anyone gets that one password, they get all of them. And that's true. But it tends to be better than the alternatives. Most people today have dozens of accounts on things accumulated over the years. They can't *possibly* memorise separate strong passwords for every one of them. The usual solution is to just use the same password (or 2 or 3 passwords) for everything. But that's *really bad*. If one site you use gets exploited, and the attacker can get your password there, they will automatically try your username/email and password combo on every other big site out there. Which means that hacking that amateur-made videogame forum you signed up for as a teenager gets them access to your PayPal account today. The idea behind tools like LastPass and KeePass is that you use a unique very strong password for every service, and write it down, but only within an encrypted vault protected by a strong password. That vault is a single point of failure, but if you use it properly, it's much safer and reliable than re-using passwords. If you're wary, then I recommend using a 'mental salt' alongside LastPass. This is some bit of text that is part of all your passwords, but which you never write down. So you set your PayPal password to \"f a 88f jv a9229 audreyhorne\", your bank password to \"$$ 209 mz z9 w audreyhorne\", and your email password to \"p----zk k2 1k1kkvvvv audreyhorne\", but you leave off \"audreyhorne\" when you save those things to LastPass. You never write that down anywhere, and just memorise it. This way, you still get a strong unique password for every service, but you don't have to memorise them all, *and* someone can get access to your LastPass vault without getting access to any actual accounts. It's like a password on top of your passwords."
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60xy6g | Why isn't ultrasonic cleaning used more, it could be used in dishwashers, washing machines, and to remove carpet stains, why isn't it? | Technology | explainlikeimfive | {
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"Cost vs benefit. Ultrasonic cleaning is pretty expensive and isn't as easy as hot water and soap. And while it would clean your dishes better than hot water and soap, your dishes being that much more clean isn't of any better for you."
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610qby | What exactly happens when you go to a huge website like Google? Are you communicating with only one computer or many? | Technology | explainlikeimfive | {
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"When you visit the google web page, A computer program run by one of the google computers will send you a web page (the search page), whilst this page looks clean and ready for your search request, it's a very special page, every keypress will make your computer talk to lots of their programs, these programs run on lots of different computers.",
"Many many. And, it depends on what you are doing. For example, Google will have many servers that run search. They'll also have many servers running Gmail, or Photos, or News, or whatever. They also run ads, so those will be many servers as well. Google most likely has thousands and thousands of computers/servers. So, looking at it more specifically with just one thing in mind (like just search, or just gmail). Here's roughly how it works: - you make a request from your browser for a website. - You ISP helps your browser know where that website is, known as the website's IP address. So, your browser can request the content from URL_0 - URL_0 has what are called \"load balancers\". These are like traffic cops. Their job is to direct traffic from customers to all the available servers that are capable of giving the answer. They're also helpful if google wants to repair or take an individual server offline. The load balancer will simply stop sending traffic tot that individual server, and the rest will take the traffic. - after the Load Balancer decides which server should answer you, the individual server with the answer, sends back the reply to your browser. That's the simple way it works. It gets more complex with larger sites or more complex internal server setup (like databases, for example), but that's generally how a large site handles huge amounts of traffic, by using more than one computer to handle the traffic.",
"hundreds most likely. Technically your router is a small computer, then there will be any number as your request is routed to the ISP, and their various intermediary steps, probably a satellite or cable, then to some Google datacenter, which in turn will communicate with multiple other computers, then the return step."
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611s32 | What did people do before IV's(Intravenous therapy) | I recently went to the emergency room because I was vomiting anything that I ate. In other words, I couldn't eat anything. So they hooked me up to an IV. What I'm wondering is what would have happened centuries ago when IV's were not invented? What was their way of treatment? | Technology | explainlikeimfive | {
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"Broth, gruel, or water by mouth until you shit yourself to death. Which is, uh, what happens to millions of people worldwide even today. Dysentery, cholera, rotavirus still kill people every minute of every day, millions of which do not have ready access to what we would consider the minimum amount of medical treatment.",
"People died a lot more often, basically. If you were unable to take meds or liquid orally, well, you didn't get meds or liquids. Blood transfusions weren't reliable at this point since they didn't understand blood types, so that obviously wasn't a thing either."
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611vnn | What the Daya Bay Antineutrino detector is and what it does | Technology | explainlikeimfive | {
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"Neutrinos and antineutrinos are subatomic particles that are emitted in nuclear reactions and can cause other reactions. Unfortunately they're *really* bad at causing reactions - most of them would just fly straight through the Earth without doing a thing. To detect them you need a large vat of something transparent, kept in the dark, and when a neutrino interacts with an atom there's a flash of light you can see. And you need to bury it underground to shield it from stuff that's not neutrinos. Daya Bay uses 20 tons of a chemical called linear alkylbenzene, other detectors used different chemicals, even natural Antarctic ice has been used. Daya Bay specifically is intended to detect the antineutrinos produced by a nearby nuclear reactor, and thereby study the way those antineutrinos work."
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6126q0 | why do drive-thru speakers have such poor sound quality compared to phones, TVs, etc? | Technology | explainlikeimfive | {
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"text": [
"They were installed in 1996 and there's never been a reason to change them. They also need to be rugged and survive years of direct weather exposure, sound quality was never the primary engineering concern."
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613bwt | How do submarines have the capability to communicate with aircraft or land from hundreds of feet underwater and many miles away? | Technology | explainlikeimfive | {
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"The short answer is they don't. Actually, they have a full range of military comms, but that only works when they are at or near the surface (they have to stick the antenna out of the water). Their other options are towed arrays and buoys, they can throw them out, they float to the surface, and stay connected with a wire so the submarine can be at depth. In practice though, they do NOT need to communicate much at all with other ships and planes, instead the high level commands have access to a very high power VLF transmitter that the submarines can pick up under water (far too big to be used on any vehicle). The submarines can't respond, and planes/ships can't talk with it. But it can be used for simple orders (surface and talk to HQ, launch missile at lat/lon, etc), so if an airplane wants a submarine to launch a missile they would radio their HQ, which would talk to submarine HQ, and they would issue the order via VLF, which the submarine can hear, the submarine would simply launch, no questions, no response. If the submarine is following a ship and they need to radio what happened, that's something that they might surface fo to periodically tell HQ.",
"Actually they have underwater speakers and hydrophones places at several strategic places on the floor of the ocean. There are low, and extremely low frequency signals that can reach subs for one way coded transmissions. (VLF transmitter Lualualei, Hawaii)."
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6142y6 | isps being able to sell our search history | Technology | explainlikeimfive | {
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"When you surf Reddit data is sent from your computer to the Reddit server which processes your request and responds with HTML data that your browser uses to display that site. ISPs can track your network usage including all the sites you make requests too (including xbox, PS4, porn, https, etc) on their network. This information can be used to tune the network or track usage. Most large employers do this already. Most ISPs do this already as well. Usually this information is aggregated (lumped together for analysis) which provides users with some level anonymity. In reality any network owner can track their network usage. Sprint, Comcast, TM, etc already track usage across their respective networks. This is how they know to throttle Sling, Netflix, Amazon, etc. What this legislation is doing is permitting ISPs and carriers to sell this data at its most granular level - the IP address. As far as I know there is no way to associate an IP address to a specific person on a home or SOHO network. It can be associated to a device through other metadata included with the requests if that data is included. Keep in mind that Google, Apple, Amazon and Microsoft all have already been doing for years. You can see this in web adverts that push stuff you just searched for. How can you fight back.... Write President Trump a letter asking him to veto this legislation. Sue. The closest would be the 4th amendment but that does not explicitly cover internet use or digital communication. SCOTUS has ruled that the 4th implicitly gives privacy rights against government intrusion. It could easily be argued that these network are privately owned and as such not covered by that ruling. This is the most likely path to success. Unsubscribe - stop using the services that do this. Economic boycotts rarely work without widespread support. Use TOR - The dark web Stop using http sites. Stick with https sites. This is only a mitigation to minimize your exposure. Browser tracking still works though. The other option is a National Broadband Network. Since this would be government owned and operated users would have a right to privacy according to rulings from SCOTUS and State Supreme Courts. However there additional conflicting rulings that would seem to imply a user would have no expectation of privacy since this would be considered a public venue. We would likely need a Constitutional Amendment to guarantee a right to privacy. This is very unlikely to happen but is the best course of action."
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614agg | How do programmers/game developers create procedurally generated worlds? | How would one code an infinitely generating world that is always different (e.g minecraft, terraria)? | Technology | explainlikeimfive | {
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"Lets take Minecraft, for example. Minecraft's world is made up of \"chunks\" which are 16x16x256 blocks in size. So, every 16x16 square surface area can have parts of height from 1 to 256 blocks tall, randomly chosen. That alone gives us over 65 thousand variations of chunks. Now, imagine any one of those blocks can also be one of, like, 20 types of blocks (dirt, stone, obsidian, lava, etc). Now we have over 1 million, 300 thousand variations. Obviously, there is some code that restricts what the chunk can look like based on the nearby blocks (so your mountain, for example, can expand beyond a single chunk). But mainly, your perception is not just of that chunk. You're also seeing the ones around it, each with their own million possible variations. Minecraft loads 81 chunks at a time in memory. Fewer are visible at once, but still quite a number. So overall, given 4 variables (lengthPosition, widthPosition, heightPosition, blockType), you have multiple millions of possible landscapes. **tl;dr** It's not infinite, it's just a *really* big number.",
"There are really just finite objects with seemingly infinite combinations. So it just needs to seem different. You have these classes of objects in your scene. You can allow different actions to affect them either directly or somewhat randomly. You can generate random seeds that index into tables of characteristics and give those characteristics to the object being generated. You can give finer gradations to things, for example, colors. Typically programmers take uniqueness from uniquely generated ids or timestamps or random function of coding language, depending on what's available on the platform. You can even build in randomness in the creation of every class or type of thing you instantiate.",
"Think of Mr. Potatohead. You have the potato body as your framework. Then you have a large variety of \"hat pieces\", \"eye pieces\", \"feet pieces\", etc. Combining those in different ways gets you something a little different each time. So game designers make a variety of \"potato bodies\" with enough variety to be interesting and apply their collection of add-ons \"randomly\".",
"By procedure. So you come up with a set of rules. For instance you want \"continuous\" ground, so any one piece of ground is only so much lower or higher than the one next to it. And the chance of any one chunk being of a different terrain type is influenced by the types around it. Then you might want to decide how high the water is on the land. And so forth. So an infinite, flat, world-of-grass is a super easy procedure to write. Adding limited mountains, like say you want from one to five significant mountains, so you pick that number (rolls-dice... four) and you place your four peaks on their spots. Then you put a tower of stuff there. Then you go back to that rule about how each square has to be only one square above/below the next. Well that tower breaks that rule so it needs to be surrounded by towers that are about the same height. Since all around them are low squares then most of the neighboring towers will be one square lower than the peak. And you keep doing that with nominally lower and lower towers with the occasional local sub-peak. Then one might want caves or cliffs or deposits of metal or mineral or whatever the game requires. So the next part of the procedure is what I'd call the \"punch outs\". A volume is punched out and re-fillied (or left empty for a cave). Now those might not be the actual rules used. Each procedural world is governed by the procedures designed and tested by the programmer. And with a consistent procedure and a consistent pseudo-random number generator, a fairly small datum (the random number seed) you can generate the same world again and again. This is because the same sequence of numbers will produce the same choices every time. For simple worlds like minecraft it's pretty simple. And with testing it got to deliverable quality pretty easily. But with No Man's Sky it went over budget and over time before delivery and they're still adding rules with each release."
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614fa1 | How can longer word documents be smaller in terms of file size than others that have a shorter word count? | Technology | explainlikeimfive | {
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"I don't know all the technical details of the Word document file format (I assume you're referring to the newer DOCX and not the older DOC) however I do have some experience working with the \"guts\" of those files. The actual text of the document takes up merely a part of the file. There is lots of overhead in every docx file: meta data, styling, presentation, potentially VBA macros, images, etc that add up to the total file size. Text itself - by which I mean plain ASCII or ASCII-like text - takes up very little room in the file. Generally, each character is one byte, so even a 10,000 word document is maybe 50k in text with the rest being that overhead. There are probably others who are more familiar with the docx format than I am, but I've written code to extract text and formatting from docx files, and to build them from scratch (well, only as far as reverse-engineering would allow me given docx is a proprietary format) so I'm sure there are lots of gaps in my knowledge.",
"Short answer: Formatting takes up a lot of added space telling the word processor how to display the text. Images are the really obvious answer, though."
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617cwr | Why are phones not lasting longer despite constantly increasing "power efficiency"? | With every die shrinkage, chipmakers like Qualcomm have claimed stuff like "35% faster, and uses 20% less power than before!" And given how batteries have been pretty much constantly hovering around ~3000 mAh since forever, why isn't this power efficiency being translated into longer battery life? | Technology | explainlikeimfive | {
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"A lot of power is used by your display, which does not reduce its power consumption with new generations nearly as fast as processors do. A lot of power used by a smart phone is not consumed by the actual CPU/GPU, and therefore, reducing CPU power consumption by 20% does not increase battery life a similar amount. The wifi/cell radios still use roughly the same amount of power. The bluetooth radio does too, as well as the myriad of other sensors in your phone. Suddenly, you update one of your apps as well, and the developer of that app decided that \"well the new phones this year have x% more power, so let's just make this feature x% more advanced and cpu-intensive, because we can\", and then a bit of that extra power/efficiency is eaten up by that new app update you did. Or perhaps another app developer thought \"we want this new feature, but developing a very power-efficient way to do it is going to take us 5 weeks, but if we just implement this much easier and less efficient way of doing it, we can implement it in one week and most users have good enough phones now to run it at an acceptable but not great speed anyway\". Repeat for tons of other apps you might have, and it adds up. Phones typically use more power because we do more with them. If I put my S7 in super power saving mode, i get literally 180 hours of standby out of it. At the same time, I can no longer receive push notifications, or run most background processes. It's great for long trips or hikes in the mountains, though. Edit: Another point to make. The push for higher and higher resolution phone screens also steals some power, not just because the screen itself uses more power now, but because the gpu in your phone now also needs to work harder to draw images that have twice the resolution. My S7's 2560x1440 display has roughly twice as many pixels that needs to be calculated than my S4 which had 1920x1080 pixels. A 4k phone needs to process 4 times as many pixels as a 1080p phone would have to."
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618jin | If two people use the same piece of software, how can only one of them have problem with bugs? | Technology | explainlikeimfive | {
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"Because they are using different computers. Say you have installed the same bathtub as your friend, but yours spurts out too much water because you have a higher water pressure in your house.",
"Different versions of the software would be the first thing to look for. You might also have different versions of libraries (.Net and DirectX are used by a lot of Windows programs). Simply how you use the software, what settings you're using in it. Also the hardware. If a program assumes it will perform some computation before it's finished loading a file, a bug might only occur on a computer with a fast disk. Also just general settings on your computer. Maybe the program assumes your computer and a server are on the same timezone.",
"My favorite example of bugs is in the original Civilization game, Ghandi was a peaceful leader with an aggression rating of 1 out of 10 (or something else low). Certain circumstances (discoveries, treaties, whatever) could lower everybody's aggression level, but this would make Ghandi's rating a negative number. The developers hadn't thought about the need/possibility of storing a negative number in that situation so it rolled over the the highest possible number, and Ghandi nukes everybody. This is typical for software bugs, software isn't released that doesn't work after a quick test or normal circumstances. But unusual circumstances can cause issues which would go unnoticed."
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618pkc | What are some of the implications of broadband providers being able to sell browsing history now? | Technology | explainlikeimfive | {
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"If you ever want to run a political campaign in the US you can simply buy the browser history of your voters and know pretty well what they think. Thus you can make better political campaigns targeted at individuals. If you tell a lie in public you will be called out on it, but if you tell a lie directly to a single person that fits their ideas then it is much harder to get called out on it. In addition there will likely be easier to blackmail people. Following the announcement of the Ashley Madison leaks there were a lot of companies targeting the users of the site who claimed they were able to delete their name from the database for a fee. Just imagine what these guys would do if they were able to buy the browser history of their targets. Do you want your loved ones or your employer to know your porn habits? What if your boss were able to find out who visited their glasspaper page right before the negative review were posted?",
"Comcast, Verizon, and att get richer and harder to force integrity upon. More people use tor I hope"
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6197mb | how does a VPN work? What is the difference of a proxy, VPN and Tor? | Technology | explainlikeimfive | {
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"A **proxy** is where you send your traffic through a 3rd party instead of being sent directly. Lets say that you want to get a package sent to your house, but you don't want the sender to know where you live or you don't want your parents to see it when it is delivered. You could instead make arrangements with a friend to have it sent to his house instead, and for your friend to forward it to you. In this case, your friend is serving as a proxy. This can have the advantage of keeping you anonymous^1 , hiding where you live to the sender (or anyone who sees your package in transit between the sender and your friend), and for you to get around certain restrictions (parents can't block it). A **VPN** (virtual private network) is a persistent secure/encrypted connection over an unsecured network. Lets say that you send letters via 'snail mail' to you friend, and you're worried about it getting intercepted and read. However, you combat this vulnerability of the unsecured mail network by scrambling your messages in a way that only you and your friend can know how to unscramble. This is equivalent to a VPN. Someone in between you and the other end can intercept your messages, see where it came from and where it's going, but wouldn't be able to unscramble your messages (assuming you use a good method of scrambling/unscrambling them). Usually, when people talk about a VPN, they're talking about a VPN that's also a proxy server. In this case, the message is received by the friend from the sender, and then scrambled/encrypted and sent to you. Conversely, if the message goes the other way, it's scrambled/encrypted by you and sent to the friend, unscrambled/decrypted by the friend and forwarded to the recipient. With this setup, someone who intercepts the package between you and your friend can know where you are, but not to where your sending (if outgoing) or where it came from (if incoming), nor would they know what the message is (because it's scrambled). Someone who intercepts it between your friend and the other person would see who that other person is, but not who are. They would be able to see what the content of the intercepted message is, since your friend had to unscramble it so the end party could understand what they mean. That is, of course, unless you and the end party you're sending to receiving from have mutually decided to scramble the message too. So this is what sending with using a VPN as a proxy looks like: You ------[encrypted]--------- > Friend -------[decrypted]------- > server So this is what receiving with using a VPN as a proxy looks like: You < ------[encrypted]--------- Friend < -------[decrypted]------- server Keep in mind that your friend will have the ability to know everything: who/where you are, who/where the other party is, and what the content of the message is (unless you and the end party mutually decided to scramble it, which is equivalent to using HPPT**S** instead of HTTP). So you better trust this friend if you're going to send anything sensitive through him. For this reason, I recommend _not_ using free VPN/proxy services. You can get a reliable VPN/proxy service for ~$40/year. **Tor** is basically a network of public servers that partially decrypts your message as it sends it from Tor router to Tor router. That way, while the first/last Tor routers will know some information, such as knowing where it's going, where it came from, or what the decrypted message is (if you and the end party don't mutually agree to encrypt it), no single one of them will know all of that information. ----------------------------------------------------------------- EDIT: This is what using a VPN as a proxy looks like when connecting using an http**s** connection: You ------[encrypted][encrypted]--------- > Friend -------[encrypted]------- > server You < ------[encrypted][encrypted]--------- Friend < -------[encrypted]------- server In this case, the message is scrambled between you and the end server, but that scrambled message is being scrambled _again_ between you and the friend/VPN. This way, not even your friend/VPN could know what the message is (assuming the encryption is good enough), because even the message he unscrambles is still a scrambled message. It also provides encryption all the way to the end server, whereas using a VPN/proxy only encrypts between you and the proxy/VPN. This is why I recommend that people use http**s**, which encrypts your traffic between you and the website you're accessing (e.g., URL_0 ). While not every website supports https, almost all major websites do. There are browser extensions, such as HTTPS Everywhere, that makes your browser try to use https by default. For those wondering, [this]( URL_1 ) is a good explanation for how one type of encryption works, keeping any interceptors from being able to unscramble the message even if all the information exchanged is intercepted. ^1 except if you give the sender information that can identify you, such as credit card information, email address, etc)",
"**Proxy**: all your *web* transactions go through a proxy server that's normally hosted on your own local network or on a trusted network. The proxy is the one who actually connect to the sites that you're visiting and relay the results back to you. Typically there's no additional encryption involved. Proxies may or may not employ data caching and history logging. **VPN**: somewhat like a proxy, with a few differences: * There's a \"proxy\" on both ends of the connection, and the communication between then (normally over the Internet) is supposed to be encrypted. * It is not restricted to web transactions. Many types of network protocols are usually supported. Unlike the proxy, a VPN isn't \"aware\" of what kind of services are being accessed, it only sees a stream of random bytes. Therefore caching and logging wouldn't be available. **TOR**: you might say it's like a VPN, however, both ends aren't supposed to know the IP address of each other. * Data streams passing through a TOR network get routed by several hosts (typically 4) before reaching its destination. This chain of hosts between both ends of a connection is known as a *circuit*. * When you connect to a TOR network, at least one circuit is established by your TOR client software and all your transactions go through them. * When a circuit is created, your TOR client receives their IP address one encryption key from each host. When each host become part of your circuit, they create a new public/private key pair and send the public one to you. The private part is kept securely stored. * When you're about to send information through the TOR network, your TOR client encrypts the data packet several times, one for each host on the circuit with its corresponding public encryption key. This layered encryption scheme was the inspiration for the name The *Onion* Router. * Each host that is about to relay your data packet decrypts it with its own private encryption key counterpart. At this point it unwraps the IP address of the next destination and relays the partially decrypted packet forward on the chain. * The last host on the chain is the one who will make the last decryption pass on your data packet and relay it to its final destination."
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619jcz | What data does Google collect from users to sell to advertisers? | With the recent vote in the Senate to allow ISPs to sell your browser history to ad companies, many people have said Google and Facebook already do this. I already avoid Facebook, but what exactly is Google selling and/or collecting? | Technology | explainlikeimfive | {
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"OK. Google collects data from several sources. Anytime your browser loads a google add, visits a google search page or any other google page it is checked for a cookie. If it does not already have a cookie, it is given a cookie. Cookies are kind of funny, think of them like tokens that the website gives your browser. Anytime a website wants it can ask if your browser has a cookie and if it does the browser will show the website the cookie. It's this cookie that google uses to track you. Cookies are also used for many other things, like maintaining a shopping cart while you browse around a web page. It's basically the only means that any website has of keeping track of a user and what they are doing. A cookie is also the method that websites that have logins remember that yo are logged in while you browse around. I say all this because cookies can be disabled, but it will make modern web browsing kind of a pain in the ass. So, when you search for something google asks for your cookie and remembers who you are. When you visit a website that uses google to place its advertising, the same thing will happen. That website will also sell additional information to google, such as what kind of items I purchased or what I was looking at. Now, this is VERY different than my ISP doing the same thing. The main reason is that I'm being tracked by the places that I visit, not my means of visiting them. Buying information from the websites I visit is one thing. Using the internet connection that I am paying for is quite another. For one, it's easy to defeat google's tracking. You can use incognito mode or turn cookies off, or just choose not to browse those websites. But when it's my ISP doing it, it can't be avoided at all. No changes on my own PC or choices not to visit certain sites can get around the tracking. Only changing to another ISP can do it and due to the nature of internet providers and monopolies that may not be an option for me. Lastly, on a personal level, I object to paying for something that turns around and sells me. It's one thing for free websites to sell me to advertisers, it's another for a service that I pay handsomely for to do the same thing. I feel like when I visit an add supported site, I'm not the customer I'm the product. But with my ISP, I'm the customer and their service is the product. Allowing them to turn around and sell me for a profit is a kind of double dipping and a change in the customer-supplier relationship that I'm not OK with.",
"Everything you type into a google search, every link you clicked after searching, every link you *didn't* click after searching, every website you've ever visited that used AdSense even if you didn't get to there from google, and specifically what you were looking at while on websites that use AdSense. In other words, every last bit of information that it is theoretically possible for google to collect from you and sell."
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61a2nv | do coax cables have any special properties compared to regular wire? Why is it used for things like TV and computers? | Technology | explainlikeimfive | {
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"text": [
"Coax cables are better at conducting high frequency analog signals than something like an extension cord because the signal on the center conductor is surrounded by a foil or braided ground conductor separated by a dielectric. The ground surrounding the center conductor shields the signal on the center conductor from electrical noise from outside the cable being induced onto the signal in the center. This is very important especially for analog signals because any amount of noise degrades the signal. The effectiveness of the benefits of the cable are generally influenced by the length of the cable (shorter is generally better), the frequency of the signal on the center conductor, geometry of the cable (diameter of the conductors and dielectric), and the material used for the dielectric. The construction of the ground conductor may also be a factor but I'm not sure exactly how that works. Digital signals can be handled differently than analog signals and are not susceptible to noise in the same way an analog signal is so high frequency digital signals can survive better in noisier environments so twisted pairs can be used in CATx networking cables. See, with an analog signal, every voltage is valid and is expected to contain part of the information in the signal so if you send 0.500000 volts but some noise gets on the line and the receiver sees 0.500073 volts, the receiver assumes you sent what it got. With a digital signal only certain voltages are valid so small voltage changes are ignored. If you have a 5 volt digital system the receiver knows you are only transmitting either 0 or 5 volts so if it sees 4.75 volts on the line it's pretty likely that you sent 5 volts and it got slightly degraded along the way and the receiver can safely treat that as if it actually received 5 volts. Also, the two conductors in each twisted pair can contain opposite information which can then be processed to further reject noise that gets induced into both conductors along the path."
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61air4 | How is this post physically represented when saved on reddits servers? | Technology | explainlikeimfive | {
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"text": [
"It sounds like you're asking for the physical mechanics behind computer storage, so I'll try to give a brief overview. All data on a computer, when you look at the most basic level, is a true or false boolean value. Through mathematics, these true-false values are used to construct every data structure we use, whether it be a variable, a database table, or an image file. Any mechanism that has two states can represent these, and it is in theory entirely possible to build a computer out of water pipes, but for sake of speed and efficiency, we've opted to use electromagnetism. All electrons in existence are in motion, either kinetically, orbitally or rotationally, and generate a magnetic field as a result. Most of the time, the direction of these fields are completely random and so they cancel out, but there are some materials whose electrons remember the orientation of the last magnetic field they were exposed to. When a Hard Disk Drive writes a bit (one true or false unit) to its memory, it creates a particular magnetic field over a region of the metal plate inside it that corresponds to a true or false, and the electrons at that place in the disk remember that field, and when the drive goes back over it, it can read what the last field that segment of the disk was exposed to, thus storing the bit. Solid State Drives work a little differently. Instead of using the direction of a magnetic field, they use quantum mechanics to trap electrons inside a computer chip. Since electrons change electric potential, the chip reads the voltage of the cell to figure out if there is an electron trapped in it, and whether or not to consider that bit true or false."
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61aoi6 | How do websites know I'm using an ad blocker? | Technology | explainlikeimfive | {
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"Basically, using a script (in this case, javascript) to detect if some assets that are used to load ads, were loaded into the page. For example, when you enter a website, a lot of files are loaded for the page to work properly, images and javascript files are some of them. Ads are usually loaded from third party script files, and ad blockers were made to block these scripts. So, it's possible to put a piece of javascript code on a page, to detect if these script files were loaded, if not, it's very possible the person is using an ad blocker.",
"Ad blockers block scripts and images that contain certain names. A website can add a script with a name e.g. show_ads.js that they know ad blockers will prevent from loading. Within this script they will assign a global variable e.g. someVarName = true;. When the page loads they will use another script to detect if someVarName is equal to true, if it is it means show_ads.js loaded so no ad blocker was used. If the variable doesn't exist the website knows that show_ads.js was blocked by an ad blocker."
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61c7bc | Why do mobile service and data providers have a monopoly on the market? Why can't new companies arise? | Technology | explainlikeimfive | {
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"Mobile service requires the use of radio waves. We are using higher radio frequencies. The FCC auctions the use of these to companies, reserving frequencies for the military, the police, emergency services, et cetera. For a new company to establish a cellular network it would have to bid for a portion of the frequency spectrum and build a network of towers along with all the other necessary items.",
"There is also a massive up front cost to building out that type of infrastructure that takes a long time to see a return on. Sprint, AT & T, Verizon, etc have been gradually building their network for years and started when there was much less competition. An interesting case study is the issues Google Fiber encountered trying to enter the market. There are plenty of articles online. Most of their issues were overcoming regulations to gain access to poles and the proper permits to build. Utility poles are interesting in that they're owned by a single company such as the power company or a telecom provider, but other people can stick their equipment on them. So if you need to use a pole with a bunch of stuff hanging from it, each company needs to come out and move their wires around a bit so there's space. I definitely wouldn't want my competitors moving my cables around regardless of how much they promise me they'll be \"careful\"."
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61e3wz | Why, despite all the advances in browser technology, does the screen still jump when an off-screen image or other part of the site loads? | If I'm reading a piece of text, I expect to stay on it. Something loading off-screen (common now that sites are so big and load lots of stuff via AJAX) shouldn't bounce me to a different position on the page. | Technology | explainlikeimfive | {
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"Because your browser still doesn't know how big that image is going to be until it downloads it, so it has no way of knowing how much space to leave. The people who design the website could plan for it, but many of them don't."
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61eiwi | Why do fake phone numbers start with 555? | Technology | explainlikeimfive | {
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"Because no real phone number start with that prefix. This means shows can use a number without accidentally giving out a real person's number - 8675309.",
"Fun fact, there are valid 555 numbers. For example, area code+555+4141 will get you 411 in that area code. How do I know this? I run a call center auto dialer. Someone was inserting bogus leads and we were dialing it over and over and over. Then we got our phone bill. Thousands of dollars I. 411 charges. Took a while to figure out."
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61f3hs | I heard that recycling plants use magnets to sort aluminium from the rest of the rubbish. How, when aluminium isn't magnetic, does this work? | Technology | explainlikeimfive | {
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"They use alternating current to magnetize the sorting magnet. If you use permanent magnet then aluminium will not be attracted to it, but if you put aluminium in magnetic field that constantly changes direction this magnetic field will generate electric curent inside the aluminium. When electric curent flows trough metal it generates magnetic field and the aluminium becomes small magnet with opposite poles as the magnetic field that generated the current in the aluminium. But the current inside the aluminium is not permanent, it's only short spike of current so if the outside field stayed the same the aluminium would stob being magnetic after a split second. But the outside field keeps changing back and forth that means the spike of current in aluminium keeps occuring and the aluminium is attracted to the magnet. Edit 1: It was pointed out to me that I got the directions wrong. The aluminium would be pushed away from the magnet. Writing it here so I won't confuse people. u/intjengineer linked a video of this in action. Linking it here in case it gets burried in the replies. If you can find his comment uvote it so it can be visible for others. [video]( URL_0 ) Edit 2: OMG I am internet famous now! What will I do with all this sweet karma?",
"In a word, electromagnetism. You're probably familiar with electromagnetism, it's creating a magnetic field by running current (in other words, moving electric charge) through a conductor. You can make [a simple electromagnet at home]( URL_1 ) to show that this works. The opposite also happens, when you move a magnetic field across a conductor it will induce current. This is how we generate most electricity: steam from burning coal, water from a dam, or wind is used to rotate magnets past coiled wires. So, now, what happens when you try and [move a magnet across a piece of aluminum]( URL_2 ), which is conductive. As the magnet – and its magnetic field – move, it creates electricity (specifically called eddy currents) inside the aluminum. These currents, in turn, create a magnetic field, and this magnetic field opposes the motion of the magnet. This can be used then, to separate metal from non-metals. By rapidly moving magnets (or using a quickly changing electromagnet), conductive materials are induced to move, and a setup is made where metal objects will be thrown forward, and non-metals fall from gravity. This, then, is the [eddy current separator]( URL_0 ).",
"So everyone here is talking about how eddy currents and magnets are used, but that's just the automated part of the process. I worked at a scrap yard for a while, I'll tell you what I and a dozen other people did every day. After going through the shredder, all the material is sorted into 2 conveyor belts. Belt #1 extends upward at a 45 degree angle, to about 30 feet off the ground where it dumps it's material over a wall and straight into train cars. Belt #2 does not move at a very slight downward incline and snakes around to dump it's material in a dumpster. Belt #1 moves at 35mph, and carries everything that the sorter deemed as nonferrous metal (aluminum) straight into a train car. Belt #2 moves at about 1mph and vibrates, rumbling all the non metallic waste to the dumpster. So after the machine does it's sorting, the rest of us go to work. Line #1 has 8-10 people on it because mixed in with the aluminum are things that have copper, brass, or are actually waste, which need to be sorted (copper and brass are worth more, aluminum load is worth less when it has too much chaff mixed in). So you have these guys standing in the air, rapidly sticking their hands in a stream of fast moving sharp metal obejcts and tossing motors and random brass/copper items over their shoulders into bins on the ground, plucking loose wires (copper) and stuffing them in 5gallon buckets, and tossing garbage onto tje ground. This process entails 15 pound motors slipping from someone's hands on the top and tumbling backwars down the belt in a clang-spinning death roll that everyone clears their hands from the path until the crazy guy (me) lets their hand get smashed when they grab it and toss it in the bin. It also entails thousands of sharp metal bits slicing your forearms and puncturing your gloves as it races past whatever item you're plucking from the line. This is not a job for hand models. Belt #2 moves much slower, and is much safer. 1 person works this belt, and it is full of the trash. Most of the stuff that went through the shredder was cars. So belt #2 is full of cushion material, plastic, seatbelts, steering wheels, and whatever people left in their car/trunk. Easily 95% of what gets plucked out of this line is just wire. It's slow, boring, and the entire line smells like a twice steamed chili fart, but you don't risk losing any fingers or hands to a rogue motor. Here is a neat anecdote. I mentioned we shred cars, the teeth of the shredder are each 2 ton titanium hammers, there is about a 1/16th inch gap between them. This machine reduces cars to tiny tiny bits. One day I was working the #2 belt and saw a piece of leather sticking out. I grabbed it and to my shock it was a completely in tact Bible. If I were to take a page from the bible and put it in the next car, the page would be unidentifiable as something from a boom when it came out the other end, either tiny shreds or pulp. Yet somehow this bible survived the entire process completely unscathed. It's now the only bible I own. Tl:dr After a machine sorts the metal, human beings risk losing their fingers, hands, and sense of smell, to manually sort what the machine missed.",
"Im on mobile so sorry for the formatting. I'm an Engineer working in the scrap industry. My job is to design facilities that shred metal and sort/recover different material types. We use a machine called an eddy current separator to recover a \"Zorba\" package. Zorba is just a fancy name for mostly aluminum. The eddy current separator is a conveyor belt with a permanent magnet at the head. The magnet is arranged with alternating poles and it spins very fast. This creates and \"eddy current\" which will make non ferrous materials like aluminum sort of jump when they travel over the magnet. We use a splitter plate to separate the material jumps from the material that doesn't. Take a look at this video URL_0 It's a bit dated, but this is one of our non ferrous recovery plants. The eddy current separator is shown working at about 1 minute.",
"So how do your recyclables get sorted in America? They combine plastic, metals, and glass all in one bin, isn't it hard/costly to separate? Is regular yeah just dumped?",
"Everything is magnetic in a strong enough field. [Even this frog]( URL_0 )",
"Fun fact, aluminum is one of the only cost effective things to recycle. Things like paper, glass, and plastic are all cheaper to produce from scratch than recycle. Extracting aluminum from bauxite is more expensive than getting it from the recycling process.",
"I like all the good science here, but it is important to note that the use of electromagnets will create currents in ALL metals. Most metals in trash are Iron (steel) or aluminum. Once electromagnets remove all metals from nonmetals, then one can separate the iron/steel from aluminum because aluminum is not magnetic in a static magnetic field, while iron is. All the other metals are likely to sort with the aluminum, but the quantity is low enough that the recycling process for aluminum can likely remove them from aluminum prior to its use.",
"As trash is getting sorted, you have a magnet that passes over the conveyor that separates all of the ferrous metals away from the rest of the garbage. Then, down the line, another magnet appears at the side, and this one creates and eddy field that pushes Aluminum off of the main conveyor on to another one at the side.",
"A moving magnetic field can create an electric current in anything that conducts electricity^1. Currents created this way also make magnetic fields of their own. These fields always push against the magnet that induced/made them. In a recycling plant, a conveyor belt flings mixed rubbish into a bin. A set of super strong magnets spins on a roller underneath the end of the conveyor. When rubbish that can conduct electricity - like aluminium - passes over the magnets, they interact. 1. The magnetic field gets close to the aluminium, and induces a current in the metal. 2. The current in the aluminium creates a magnetic field. 3. This field pushes back against the magnets under the conveyor. 4. The magnets continue to spin. This moves their magnetic field closer to the aluminium. 5. The magnetic field around the aluminium continues to push back. 6. The magnets push harder than the aluminium can push back, flinging it off the conveyor faster than other rubbish. 7. Aluminium and other conductive metals are flung into a farther bin than the other rubbish. ^1. This is how electric generators/dynamos work. Steam spins magnets inside a copper coil, creating a current. The magnetic field more or less 'pushes' the electrons around the wire, and electrons moving *en masse* like this are what we call electric current.",
"Or the use the magnet to catch all the ferrous metals like steel or iron and what you left with is aluminum, copper, tin.",
"Generally speaking if a material will conduct electricity at all (even barely) it is subject to this...",
"Aluminum is not magnetic, some facilities use an eddy current system to sort mixed metals. Edit I work in the metal recycling industry....",
"Alternately they grind everything up and drop it into a conveyer belt. This belt has sensors that can identify all kinds of stuff in various ways. From there it is dropped into a chute that shoots each piece with air jets to push it into the correct hole that lead to collection bins."
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61f6kn | How much of our fingerprint do a reader need to be recognized uniquely? | Technology | explainlikeimfive | {
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"Source: I'm a final year forensics student and currently writing a paper on fingerprints. I'm in the UK so ymmv. Depending on what you mean by 'reader' and how sure you want to be the answer varies. Fingerprints are examined on 3 levels by people and databases. The first level is the general shape (whorl, arch, etc) and is not unique. To get this information you could use a full print, half, or less depending on what there was in that section (e.g., it isn't an arch if it has deltas). The second level is a closer look if you like. You look at where the ridges end, how the paths they take look/ where they split etc. This is considered unique and mostly in criminal cases can be done from a pretty small sample. The third level looks at exact heights of the ridges, distances between them, positions of pores and more. This is unique also and also needs only a small sample to be identified. Depending on where you are a fingerprint could be identified (by comparing a found print to one that you know the origin of) by finding 16 'matches' of features, 14, other numbers, or up to the person comparing. tldr: not much if there's something to compare it to."
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61fd8o | Why was Bitcоin designed with a block time of 10 minutes? Wouldn't lowering it to, for example, 10 seconds, significantly speed up transaction confirmations and make it more usable in the real world? What would be the downsides of a lower time? | Technology | explainlikeimfive | {
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"Personally I think that the creator probably chose the 10m block time so Bitcoin can run on more computers and use less bandwidth. This bandwidth is incredibly important as the currency grows, more bandwidth is needed for each update. It would also be a lot easier to mine the Bitcoin, lowering the value as more is available to the market. The amount of energy used per Bitcoin would also decrease drastically, meaning less security because there would be less risk to scammers that try to cheat the system and have to invest less money(electricity) Here are is a more indepth look at the pro and cons: URL_0",
"Some possible answers: If it is solveable fast that would mean more forks. Also solving the hash puzzle would become too easy.",
"As a side note, Bitcoin will _not_ replace our current system. It wasn't intended to get so popular when it launched. There are many people working on newer blockchain currencies taht have many improvements, one of them is faster block minutes. The reason why these aren't released yet is that they don't want to split up the community. It will be released when it's done."
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61fpe4 | Whats the difference between AM and FM radio? | Technology | explainlikeimfive | {
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"The analogy I saw was that you have a tower with a light on top that is used to send messages. AM is like changing the brightness of the light to send the message. FM is like changing the color that the light is showing. Edit: changed blinking to color",
"To understand this, first you have to understand what a radiowave is. Radiowaves are electromagnetic waves. We are surrounded by electromagnetic waves all the time, in fact, depending on the frequency (a measure of how often a wave repeats), we can even see some of them. These waves we call \"colour\". We cannot see the other waves, but we can use them to carry information. How can we store information in electromagnetic waves? There are two ways: We can change their frequency (**F**requency **M**odulation) and we can change their amplitude, the \"peak\" of the wave (**A**mplitude **M**odulation). Radios can receive these radio waves and convert the information to what we hear.",
"The main benefit is that FM has a higher frequency range compared to the AM frequencies. That is how FM, which generally only once played classical music became the entity it is today. FM was also the first audio delivery system to broadcase true stereo fm. Some of the earlier models required a separate amplifier and speaker for the other channel. Rock radio began buying up the available frequencies so they could have the best of both worlds. Many of the AM stations became more sports involved as quality of broadcasts really did not make that much better. After all, sports is sports right?",
"I'm not a physicist or an engineer, but I'll give it a shot. AM radio works by *amplitude modulation*, which is where the size of the wave in the signal varies but it all comes in at the same frequency. FM radio works by *frequency modulation*, where the frequency changes but the wave is always the same height.",
"The difference between AM and FM radio is the wave frequency they are transmitted on. AM waves are longer and more drawn out, however FM waves are slightly shorter and more bumpy.",
"Since others have already given you a decent explanation but no pictures, [here's a visual I whipped up]( URL_0 ) that makes the difference between AM (**A**mplitude **M**odulation) and FM (**F**requency **M**odulation) clear. Both of those waveforms represent the same underlying information, but they do it by encoding the information in different aspects of the signal (either by changing the amplitude or by changing the frequency)."
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