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kkbe2g | - Why are 5G speeds worse than LTE when industry has been praising how fast we’d be surfing with it? | Technology | explainlikeimfive | {
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"Because its not really fully developed yet... the u.s. and china have been in a race to both develop it peoperly... naturally since we havent been able to the cell peoviders released a \"5g\" network that doesnt really work at the same speeds... in short... your 5G signal is nothing more than 4g. LTE with a different brand"
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kkfvz7 | How are PCs better for gaming than specifically designed gaming consoles? | I don't really play games all that much but a couple of friends have said things to me recently about games being much better on PC than on PS5 or Xbox one. Seems sort of counterintuitive to me that the device specifically designed for playing games on is worse for playing games than a computer that has gaming as one of many functions. | Technology | explainlikeimfive | {
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"Simply put, computers are just considerably more powerful. Gaming computers tend to cost more than a console so they can use more expensive parts. Something like the PlayStation 5 will continue to use the same parts pretty much until the PlayStation 6 comes out. So while the PlayStation 5 is behind computers now based on price, in a few years the hardware will also be quite out dated allowing computers to pull further ahead. Computers also have the ability to upgrade as you go without having to completely replace.",
"Gaming consoles are designed to be economically mass produced. They have a moderate level of computing power in order to be able to ensure smooth gameplay without being so expensive that you can't afford them. PCs are fully customizable and upgradeable to be able to operate on levels far beyond the capabilities of a console. When I build a new machine, I make sure I have plenty of room for it to be expanded or upgraded, and my last machine lasted me ten years.",
"It's more a case of component capability. A Console has to be priced in such a way that it is financially accessible and mass producible, so it is locked to a specific configuration of hardware, whereas a computer can be improved and is nor bound by the same price limits. A console would far outstrip a computer of the same price, but a $3000 gaming PC will beat a console.",
"- PCs are more powerful (because they get upgrades constantly, while a new console only comes along every few years) - They're customisable (you can have whatever parts you want instead of whatever the manufacturers decided) - And, for me, the biggest benefit: the library. A console is limited to a timespan of maybe 6 years when games are being released for that. Backwards compatibility is usually limited so you can't play anything released before or after that timespan. A PC can play any game ever released for PC, in theory. For older games it might take more work to get it running, but it's never going to straight up tell you 'you can't play this, you have the wrong PC'. And even if your PC is a bit old you can maybe still play newer games on the lower settings. A console eventually reaches a point where nothing is being released for it anymore, and even indie games that should be able to run on basically anything just aren't sold for the older console.",
"Higher end PCs have stronger components than a console. Like, what better at towing a car, another car or a tow truck? Also, in general PCs can be upgraded as the better components come out, consoles can't.",
"There's a lot of factors that go into it. What it usually comes down to is that PC components are constantly being improved. In a year or two, PC will have bigger/better RAM, faster/better CPU's, better GPU's, and more hard drive space, all available. But Consoles are generally only designed for a very specific set of hardware, and they don't often update it. That is both a blessing and a curse for Consoles - the game developers can optimize it very well for that specific set of hardware. But there's only so much optimization you can do before you hit a wall of what the hardware is capable of doing. -- As a sort of \"case in point\", PC gaming has had 4K, ultrawide, and/or 144hz FPS available for a very long time now. And consoles are only recently \"catching up\" in terms of offering that kind of \"power\" from their hardware."
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kkgadi | What does "pushing" and "pulling" film in a 35mm analog film camera do? | I've been taking photos with a 35mm camera for a bit now, and I've been trying to wrap my head around this to no avail. What exactly does it do? Is there a noticeable difference in the outcome of the photos? Is it all for experimental purposes? | Technology | explainlikeimfive | {
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"if you understand digital photography, it's like shooting to the left or shooting to the right. you purposely underexpose or overexpose when shooting and then you either push or pull it to correct the exposure when developing the film by modifying the length of time in the developer. you can do it to get creative effects or to compensate for exposure. & #x200B; **Push – Low light and shutter speed not suitable for handheld photos.** Low light is this is the most common reason people push. As a guide, when shooting handheld with an SLR, it’s best to keep your shutter at or above 60th of a second. With a rangefinder, you want to stay at or above a 30th of a second shutter speed—for anything lower you should either use a tripod or push your film a stop or two. **Push – Creative effects –** Pushing is a fun way to change the look and many people push B & W and color film to get more contrast and increased grain – the more you push it the more contrasty and grainy your photos will be. Color film will have more saturation and possible color shifts. **Push – An overcast day or the sun is going down.** Shoot a 100-speed film and gain two extra stops (+2) by shooting at ISO 400 and develop it at ISO 400. **Pull/Push – You didn’t change the speed on your camera.** You shoot 400 film at 100 ISO. Develop it at 400 (+2 Stops) and your photos should come out fine. **Pull – Sunny, bright and high-contrast light.** Pulling film reduces contrast and brings out details in the shadows. **Pull – Creative effects –** Pulling film mutes colors and flattens image with less contrast."
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kkiweg | How can 2 different CPU’s of the same model have different overclock potentials even though they have the same architecture? | Technology | explainlikeimfive | {
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"There are very slight variations between chips, both a benefit and a detriment to the way they're produced. Obviously every chip that makes it into a package has probably tested to be able to run at the rating on the box with no problems. Those that fail get tossed. But there are some where there are less imperfections or whatever, where they are (at least in theory) capable of working at a higher speed. The box rating is just the absolute baseline of What constitutes a sellable CPU, and is what is proven to be completely stable.",
"Making CPUs involves photolithography, which is basically shining light through a mask and through a lense onto a piece of silicon. Rather than magnifying the image it shrinks the image down and then light reactive chemicals are used to cut out the circuit paths. This is an incredibly delicate process. CPU fabs cost *billions* of dollars to build and require rooms far cleaner than any hospital that are isolated from the smallest vibrations since at microscopic level a spec of dust is like a boulder and a footstep is like an earthquake shaking everything out of alignment. CPUs are made together on plates of silicon and when the process is finished the plate gets cut up into squares like a party pizza (so one plate may have a hundred CPUs). But due to tiny variances, impurities and such each CPU is unique. Some pathways may be slightly narrowing or slightly wider or slightly thicker which alter their electrical resistance. Some pathways might even be broken or crossed with a nearby one. For this reason CPUs are *binned*. This is a testing process in which they are sorted and labeled. So an i3, i5 and i7 may all come from the same batch of CPUs and are only labeled once they figure out how fast they can be run and whether all the cores and cache are working properly or if some need to be disabled due to defects. So all CPUs within a certain range of potential speeds are grouped together and sold as one model, but they will all be slightly different. As yields improve it will generally result in more CPUs that can reach higher clock speeds and depending on demand a manufacturer might even mark some higher CPUs as a lower one simply because their is greater demand to be met for the cheaper CPU (leading to cheap CPUs that can be massively overclocked). The fact that CPUs are also binned by defects means that a CPU with a certain number of defective cores might still be able to reach the highest possible clock speed on the remaining one."
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kkr4yz | how does services like Soundhound identify music so quickly with such limited information? | I can understand recognizing lyrics quickly with voice recognition, but how do these things figure out instrumental music, or music based off of a person just humming something? With the huge amount of songs out there, this seems impossible and incredible to me. | Technology | explainlikeimfive | {
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"There a quite a few factors going into this miracle of technology. Without going into detail, such feats in music recognition are due to the incredible amount of effort that has been put into signal processing sciences over the last century. And also a bit of Big Data. If you want more detail here are a few pieces of the puzzle. The exact reality of how apps like Soundhound and Shazam work likely combine all of these pieces, and probably some more. First there are well-known methods to recognize a song from the real recording. That's not really \"voice recognition\", it's more general than that. 1. The first piece is frequency analysis, and all its variants (real time Fourier, wavelets, etc.). It allows you to analyze the frequency content of a recording. This content can be easily compared (this is called cross-analysis) to the frequency analysis of your reference material (your song library if you wish). The reasons for that are complex and they're at the root of why Fourier analysis (and other kinds of frequency analysis) was developed and is so widely used. 2. Even if you were playing the real recording, chances are there are other sounds being recorded from your phone (a car passing by, or even your friends who won't stop singing while you're trying to use the app). That's a signal separation problem.. The idea is that you know that there are multiple sound sources, but you want to isolate just one (keep the music playing, and not your friend singing over it). It is one of the big problems in the field of signal processing, and so we have a few algorithms to solve it, at least in part. So what about when it's not an original recording, but just humming? 1. The thing is, you can still try the solutions above. If someone sings well enough, the frequency content of their singing will still match the right song slightly better than the other songs in the library. But that's usually not enough 2. The next thing you can do is make the problem as simple as it can be. Instead of analyzing the frequencies involved (which basically means determining the exact notes someone is singing), you can just analyze the variations in pitch. So instead of giving a name to a note, the algorithm just has to determine if the next note is higher or lower than the previous note. That same analysis has also been done on the songs in the library. So instead of comparing audio signals, the algorithms just has to find the closest matches for a list that would look something like \\[up, down, down, up, same, up, down, same\\]. Intuitively it's easy to see why that would make it faster. And it's not necessarily less accurate than a full frequency analysis. 3. Then there's rhythm. Determining the rhythm of a song is something that isn't too hard. There are a lot of patterns in most styles of music, like beats being accented by percussive sounds, and also rhythm being fairly stable. Once the app knows what tempo you're humming/singing at, it can look for songs with similar tempo. It can even stretch/compress your audio a little bit to see if it makes it match better with its song library 4. The final piece of the puzzle is simply having a lot of data. Soundhound (and probably Shazam as well) has a library of the song recordings, but also a library of people singing the songs. And it's much easier to match two people singing the same song than it is to match a person singing and the song they're singing. Finally there's the fact that even though there are millions of song recordings, most music searches will actually be focused on a small subset of them. So it's logical that the apps will focus especially on popular and/or recent songs that are more likely to be searched."
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kkul1m | why do modern vr headsets need powerful pcs to run videogames? | The games seem to have the same graphics quality as consoles and I can probably rotate a my L stick as fast as a headset, so what am i missing? | Technology | explainlikeimfive | {
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"Modern vr headsets have 2 different screens in them(one for each eye) so thats already double the processing requirements in terms of graphics alone. Also, steady and higher framerates are needed to not only help visuals but prevent motion sickness further increasing the already doubled graphical requirements. There is also extra processing required for motion and positional tracking for headsets and controllers. There are also a few other additional processing additions, but those are probably the most significant",
"To add to the other great answers, the frame rate has to be high. In normal games you may get away with a lower frame rate (especially for graphics-intensive games) . It may not look great, but its playable and most gamers will ignore or get used to it. For VR though, not only is motion sickness a problem, but any lag at all can cause general disorientation. Its very difficult to adapt or play a game with it. Imagine if your body took a second (or even more) to react to your brain's \"commands\". Its not something thats easy to deal with as a user/player. Further, theres already a lag caused by sending the images/graphics rendered on the computer to the VR headset/devices. By itself, most humans cant detect that lag, but adding much more to it makes it very easy to detect. Since that lag isnt something you can do anything about, the computer has to take on the burden or compensating (or making up for) that lag that already exists.",
"The need to run two separate displays each with their own image (due to the desired 3 dimensional effect), and the need to maintain a high frame rate",
"You need to render the game twice, once for each eye from slightly different angles. Doubling the graphics requirement is not a small ask, aside from the fact you need to maintain a good framerate to minimize motion sickness."
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kl2m7b | what is clocking and overclocking I’m so confused | Technology | explainlikeimfive | {
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"Clocking isn't really a thing, but overclocking is a method of increasing your computer's speed. Basically, the part of the computer that does the thinking is limited to a certain speed and voltage to prevent errors and damage, but mainly overheating. So, some people like to 'overclock' the processor to go past this limit, and then install a better cooling system to compensate. This allows them to have a faster processor at a lower price. It is called overclocking because it increases the 'clock rate' of the processor. The clock rate is basically the speed it can 'tick' at, or create cycles that can be used for processing."
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kl5qi9 | Why does the phone camera's quality look good, but the photo taken is worse? | I noticed this phenomenon in a couple of Androids and even some iPhones that the camera looks really good when you're not shooting anything, and it's just staying still. However, the photo captured looks significantly worse than the pre-shoot camera's quality. Even when you set the camera on timer and place it on a tripod, the shot still looks worse. Details are lost. Image looks flatter. What is causing this, and what phones do a better job at capturing photographs? | Technology | explainlikeimfive | {
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"The only reasons I could think of are: \\- There is some post-processing happenning (e.g. aggresive denoising) that is actually making the image look worse (most likely anwer) \\- There is some strong image compression happenning (\"smallest file\" setting, shouldn't be a thing) \\- OR the still image isn't technically worse than the live camera image, it only appears that way subjectively (e.g. because the still image is viewed on a larger screen, judged by harsher standards etc.)",
"Is it possible the picture you are taking you have it set to store as a lower quality image than what your phone is capable of capturing? So when you are looking at the screen it looks great, you take the picture, it lowers the resolution due to your settings, and then the photo you look at is worse?",
"Phones can have brilliant cameras and specifications without necessarily being able to display it. Theres no way my phone can accurately show me what the 108MP picture i just took looks. At the same time, it depends on the phones camera AI and priorities, what it needs as an ideal condition, and what post processing the phone does. Theres also the absolute horseshit that snapchat does, but im not going into detail about that.",
"Good question. I had an older phone with 12 MP camera, and some times it took awesome photos, some times it was absolute shit, it had nothing to do with lighting, or about the focus it was something else.",
"So, first of all, phone cameras cheat, a lot. They have very small lenses and are technically not able to get good photographs so instead they shoots many photographs from one or more cameras and then use very advanced software to create photo. If the software has some badly configured settings it might influence the final photograph. That said, what you describe is probably just subjective, your brain is able to accept move imperfections in a moving image than it is in a static one where you have time to look at all the details.",
"Are you asking why the photo looks better on your phone screen than on your computer screen? Or how the live-preview looks better than the actual capture made and saved?"
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kl6wf5 | If the internet is primarily dependent on cables that run through oceans connecting different countries and continents. During a war, anyone can cut off a country's access to the internet. Are there any backup or mitigant in place to avoid this? What happens if you cut the cable? | Technology | explainlikeimfive | {
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"Think of it like closing an interstate highway. If I-95 suddenly disappeared, you could still drive from Miami to New York; you'd just have to take alternative (longer) paths, and you would be further slowed by all the other cars taking that route instead of I-95. Internet routing works the same way. There are redundancies built into the system, whereby traffic will take an alternative path if its preferred route is blocked. Now if ALL the cables got cut and there were no alternative paths to take, then yes. The affected continents would be effectively cut off from each other for internet purposes.",
"Cuting the cable cuts the internet. But it depends on the country. Cuting the internet to France is difficult, as there are multiple cables connecting France to other countries. But less developped countries are vulnerable. A few years ago, a cable was cut down in southern France, shutting down internet in most of Africa. Although backup cables existed, they couldn't handle all of the traffic.",
"Not necessarily in times of war, but there have been incidents of cable breach. From time to time you’ll hear of large outages to say Southern California or Japan. These are a result of cable damage. Usually a result of large scale fishing trollers or petroleum exploration. Technology and mapping have gotten better to help prevent this. GPS is now much more accurate. This is important in mapping where the cable is dropped and important on mapping where the vessel is trying to avoid the cables. Picture your town and you wanted to dig a pool. Now you call the utilities and they come and paint lines across your property where underground service is located. In the early days of transatlantic and transpacific cabling, your utility company would only be able to say “yup we have cables buried under your block somewhere” and that was the closest info you could get. As for redundancy… that costs money and has to be weighed against the likelihood of needing it. It would cost millions upon millions of dollars to drop a second run of cable. Is that expenditure risk worth it now that location can be better determined? That’s up to the service providers to account for.",
"On top of redundant cabling others have mentioned, even if you managed to cut every single cable that goes into a country they would not be fully cut off from the internet(although their bandwidth would be miniscule by comparison). Satellite connections to the internet are available around the globe and, short of blowing up all comm satellites, impossible to block.",
"In modern times, there are backups to the intercontinental cabling, with satellite based internet able to serve when the cables get cut off, plus there are more than just the one set of cables connecting everything. Even without those cables or a backup, the internet would work just fine, you just wouldn't be able to access other countries' networks. It would splinter the internet into fragments, with China's Internet unable to connect to America's Internet, which in turn would be unable to connect to Europe. But Microsoft could build a server farm in America and allow people to play their XBOX just fine. As for why they use these cables instead of satellites normally, it's because the distances are greatly increased beaming the signal up into space to be bounced around the planet, and latency would be increased to an intolerable level, so satellite internet is currently limited in scope for remote areas, where sending cables and fiber optics are not feasible.",
"Few years back a grandmother in Georgia (the country) accidentally severed a line while gardening. Took the entire country off line for weeks.",
"One of the chief design goals of the internet was its durability. The internet as it exists now, particularly with the web, is very different in design and purpose than its origins as a tool for military communications during the Cold Wars. The goal was that there was no \"central hub.\" There isn't even a singular internet. It's just various communication tools connected to one another. If one gets cut off, that's not going to crash the whole system. You could split it in two, and each half will function perfectly fine, just as if you had simply disconnected one device. While there's been a lot of infrastructure built up around the internet that does give elements of centralization to various extents (see what happens when AWS or Cloudflare goes down), the core of the internet's design remains in place. A web service outage might cause a lot of websites to go down, but it's not going to stop your online game session. A state might cut off its internet to suppress protests, but that's not going to stop the functionality of the internet for other countries.",
"Before internet but after cables in wwi britain cut all the cables from Europe to america that didn't go through the uk. Those they tapped. This led to intercepting the zimmerman telegram and the us declaring war on germany.",
"Hitting the undersea cables is a common tactic during war. It was a specific focus during the Cold War in fact. Both the US and Russians spent a lot of effort locating and either accessing or mining their opponent’s undersea cables. The US even figured out a way to passively tap Russian cables early on. Now a days there are a lot more cables and much more commercial use for them. Check out URL_0 . Finding all the cables would not be easy, especially in the depths of the major oceans. The military also has satellite communications so losing physical cables would have less impact.",
"There are a lot of good replies here. I would also like to point out that the cables are very hard to locate and very hard to access. Once the cable is shored, it is buried 2m under the surface. Thats usually to about 70-100' of water. Afyer that they are laid on thw surface but eventually get buried. Once laid they are only mapped after and that always changes due to a few factors. If there is a shallow water break we just run a new shore in and leave the old cable where it lays. Just way to much hassle to find and deal with. Omce in deep water you need very specialized vessels, location equipment and service equipment to deal with it. Not to mention not people people in the world do this kind of work. I guess you might be able to luck out with an ROV but odds are not great. Once done most major countries have multiple redundancies and can get it repaired pretty quick.",
"There isn't just one cable there are lots of them and the information can be rerouted around any damaged sections. In the relatively early days of the internet lots of the cables ran directly under the twin towers. The fall of the towers added to the dramatic increase in the amount of traffic as people wanted to know what was going on brought the internet to a near standstill. Since then there are a lot more cables and redundancy built in to the system.",
"Depending on how you define it, the internet isn't primarily reliant on international cables. You (usually) only use those cables for international routes. Most big services will have a 'local' presence or at least a cache in a data center within your region. Your in-country internet will largely keep running and even international routes will reroute via less efficient options - either longer routes, cross land border cables, terrestrial microwave,or even satellite backups for those with enough money to purchase them. That's what the internet was primarily designed to do, by DARPA. It's quite good at doing so. Also, in most western countries at least, there's a lot of cables. It's not trivially simple job to cut them all & everyone would get very 'excited' by their loss...",
"The internet has massive redundancy and the ability to route around broken (or even just slow) connections. That's one of its design principles.",
"The cables are believed to be mined by the major powers who have submarine warfare capabilities. They can blow them at any time, but probably not until open warfare begins. Cutting the cables would destroy cable based communications. Radio based communications could continue to work, where they aren't jammed, and where satellites haven't been destroyed, but overall, global communications would be severely compromised.",
"Its called the interNET for a reason. Think of a fishing net. There are several ways to reach any specific point in the net. Make a few cuts in the net and you can probably still go from any point to any point.",
"Yes, there are backups. Even if a country is completely cut off from the outside world - depending on where you are, major services will keep working like nothing happened. Tech companies like Netflix, Amazon, FB, Google(and many more) have data centers with copies of your data almost in every country, so they'll work as usual. It's like you had a Chick-fil-A on every block. Even if the 2 of them along your commute shut down for some reason, you can go a little bit out of your way and get your sandwich from the next block."
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kl97mm | waterproofing electronics | Why cant manufactures spray some plastic laminate type coating on circuit boards to make them waterproof? | Technology | explainlikeimfive | {
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"Its called [conformal coating]( URL_0 ) and is used in certain industries where the device needs to be really really resistant to moisture and dust and general board contamination The protection is nice but it comes with a lot of downsides. The application process can be icky because it coats *everything*, it basically glues all connections in place so no replacing the screen on your phone if it gets cracked. It also traps heat into the board which can lead to overheating if not done right, and also just increases the cost of the whole assembly process. For the most part consumer electronics just need to be water resistant and at a favorable price point. Sealing the outside of the casing gives pretty good water resistance while letting phones get repaired/refurbished which keeps the price down.",
"Electronic circuits can be waterproofed and ruggedized with conformal coatings. User interface and replaceable items such as switches and batteries need different solutions but it is still possible. It tends to add substantial cost. It makes them difficult to repair. It is more common in military applications.",
"They actually do this, its the primary way electronics are made water resistant. This is pretty much what making water resistant electronics encompasses. Many consumer electronics use this process on expensive devices (this isn't cheap or easy), and military, defense, industrial, and boating, and such use this on a lot of electronics as they are designed to operate in a variety of environments You coat the electronics in a water resistant material. It makes it resistant to a lot of water-- not waterproof, but water resistant."
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klbglb | Can someone explain to me how AND, OR and NOT gates make it possible to do anything? | I watched a video on how computers make decisions and it’s all based on these gates and with enough combinations you can make anything possible. But that’s still too far a jump in my head. Can anyone give an example of how these gates might get something running and then take it to a bit more advanced level so I can see how it can make something like a whole computer run without being too technical please? | Technology | explainlikeimfive | {
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"That's tricky without going into too much technical detail ;) Essentially, you can break everything the computer does to adding binary numbers and storing data. The adding numbers is done using a *Half adder* or a *Full adder*. Wikipedia has the diagram for either. Half adder: [ URL_1 ]( URL_0 ) Here, A and B are binary numbers (0 or 1). S is A+B so A=0,B=0: S=0 A=1,B=0: S=1 A=0,B=1: S=1 . C is the carry over (remember from written additional) for A=B=1: A=1,B=1: S=0,C=1 You can combine these together to be able to build hardware that can do addition of arbitrary-length binary numbers. If you can add, you can do everything else. Substraction: addition of the negative number. Multiplication: repeated addition of the same number. Division: Subtraction until you can no longer subtract and count the number of times you did the subtraction & #x200B; To be able to store values, you can use a *flip-flop* or an S/R latch: [ URL_3 ]( URL_2 ) This component stores a single bit. S is the Set value and R is the Reset value. If you put S=1, then the system remains in Q=1 and Q\\_bar=0 until you put R=1 which causes Q=0, Q\\_bar=1. This means that you can perpetually store the value that you have put into this. Put this simple thing together a couple of million times, voilá, you have a memory."
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klbtpl | Why is it so difficult for movie studios/sound crews to create a soundtrack that prioritizes dialogue so that I don’t have to turn the volume up to 4,000,000 to be able to understand what is being said? | Technology | explainlikeimfive | {
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"Home theater guy. It's because the audio is mixed for a theater. Sometimes you can get a more reasonable sound mix for home viewing if you choose Stereo in the Audio options menu, but obviously, that's not ideal if you have an actual surround system. Some disc players and audio video receivers have a \"night mode\" that attempts to equalize audio, with varying degrees of success. The real solution would be for the producers of the content to make an audio track that is mixed for the home. Very occasionally you'll run across one that does, but it's hardly the norm. I also don't know why streaming services don't offer it. The vast majority of the work could be done programmatically.",
"If you listen to recordings of classical music, you’ll run into a similar problem: it’s often way too quiet, and then gets way too loud when it hits a crescendo. Volume is a dimension along which music and other audio can be intentionally designed to operate. The movie gets very loud during intense scenes, but is meant to be “normal” otherwise. This works fine in theaters (for movies) and concert halls (for music), where it’s perfectly fine for things to get super loud every now and then. But when we’re watching at home we don’t want to annoy the neighbors or wake the baby in the other room. So we have to keep raising the volume during dialogue and then lowering it during action scenes. If we eliminate the very loud parts, we might weaken the dramatic or emotional impact of certain scenes where the volume plays an important role.",
"This may have something to do with your audio settings. If you're set up for surround sound and the dialogue is coming through the center channel and you don't have a center channel speaker, that could do it. You might try fiddling with different setups to see if that helps.",
"Seriously, I have hearing loss in one ear and I can never make out what is being said in movies. I always try to have captions on everything, but it takes away from the feel of the movie."
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kldhhz | On sketchy sites, why do some pop-ups get blocked but others don't? Shouldn't all pop-ups be blocked by turning on the pop-up blocker? | Technology | explainlikeimfive | {
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"An ad blocker has to decide what's website content and what's an ad. If a website owner decides to manually post an image of an ad to their website there's not much an ad blocker can do to determine that's an ad and not website content because in a way it actually is website content. Usually adblockers block the ads that have to load from external sources."
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klh7y9 | What exactly is different about 5G than 4G, 3G, etc , and how exactly is it better? | Technology | explainlikeimfive | {
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"Every five years or so, the major cell phone companies get together and decide on the next developments of their technology. This is a huge undertaking. It is not not enough for Samsung or Apple to come up with a technology for how their phones communicate. The companies who make the base stations and the network software also have to agree to implement these features. The carriers, companies like Verizon, AT & T, etc. also weigh in on these decisions. With 2G and 3G, phones could barely browse the web: the signal could simply not carry data fast enough for things like videos. This speed was improved with 4G, but new we have a new problem: billions of people, all trying to share the same set of radio \"channels\" on which our phones run. New for 5G is a large set of new radio frequencies that the FCC (and regulators in other countries) has allowed for use with smart phones. Studies of communications on these frequencies show that they can carry data extremely fast, but not over long distances. Thus, these will likely be implemented in dense city areas.",
"Different modulation techniques is one difference, ways to squeeze more information into the radio waves they are allowed to use. if you think of a radio signal like wobbles in a skipping rope, Amplitude Modulation (AM) would look like larger and smaller wobbles, Frequency Modulation (FM) would look like faster/shorter wobbles, and that did us fine for music and voice broadcasts etc, but when you go from a few radio stations, to every person with a phone basically being a radio station transmitter and receiver there just isn't enough room to squeeze all that traffic down the rope. You can use more ropes (more frequencies) but you run out pretty quickly, especially as nearby ropes interfere with each other. What you can do is very careful scheduling, kind of a timeshare of the ropes, if each person gets a go on the rope to send their bunch of wobbles in succession, but for only a set amount of time, they might need to queue up multiple times to send fragments of complete messages, and the person at the other end of the rope needs to know which wobbles come from which time slot then stick them all together to make the complete messages and pass them on. This would be Time Division Multiplexing (TDM). Likewise you could use Frequency Division multiplexing ( a whole mixture of sizes and lengths of wobbles all sent at once down the rope and made sense of at the other end by only looking at all the wobbles of a certain size and shape for one message, another size and shape for another message etc. Then while doing all this at once, if you are still running out of space on the rope, more people want to use it all the time plus now they want it to carry much more information compared to the old voice messages, they want pictures, videos, files of all sorts. So they start to think of new ways to wobble the rope. One way might be to start wobbling it not just up and down, but at various angles, eg top left to bottom right, or side to side (still keeping up the old wobbling techniques too). This would be the equivalent in radio of using Phase Shift keying. At first you might only be able to detect big changes in direction, but as you get better at it, you can start making smaller and smaller shifts in angle to carry more messages at once. or more information in each message and the other end of the rope would have to get better at detecting them too. So you've got loads of ropes now, all using better and better techniques to send more information down them faster, and now and then people are still coming up with new ways to use the rope, or just get better at the old techniques, read smaller,faster wobbles or smaller angles, but both ends need to be using the same systems or it's just gibberish. Since everyone has to be using the same techniques and have the same ability to read and send wobbles in order to communicate, they save up all the improvements over time until the effort and cost of making the change is worth it (use a new method and the entire infrastructure needs to be upgraded), hence they come out as new generations.",
"[Verizon ]( URL_0 )has a page that explains the frequency ranges: The radio spectrum includes frequencies between 3 kilohertz (kHz) and 300 gigahertz (GHz). Early cellular networks, including 1G, operated at a frequency of 850 MHz and 1900 MHz. Then, 2G and 3G networks operated at additional frequency bands and spectrum around 2100 MHz, and 4G LTE technology operated at additional frequency bands and spectrum around 600 MHz, 700 MHz, 1.7/2.1 GHz, 2.3 GHz, and 2.5 GHz. 5G Ultra Wideband, Verizon’s millimeter wavelength (mmWave)-based 5G, operates at frequencies of about 28 GHz and 39GHz. This is considerably higher than 4G networks, which use about 700 MHz-2500 MHz frequency to transfer information.",
"The G is generation. As with each generation we have new improvements in technology and requirements for faster network speeds. 30 years ago it was cool to talk to someone wirelessly. Then 15 years ago it was cool to send words and then later pictures. Then 10 years ago or so we can now video chat, stream movies send. Each generation allows more customers, more bandwidth, faster speeds and better security."
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klkplt | How do lights with multiple light switches work? How is it that flipping one switch on when the light is already on turns it off? | Technology | explainlikeimfive | {
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"The 2 light switches are connected via 2 wires. Call them wires A and B. If switch 1 is on wire A and switch 2 is on A, the light is on. If switch 1 is on wire B and switch 2 is on B, the light is on. If switch 1 is on wire A and switch 2 is on B, the light is off. If switch 1 is on wire B and switch 2 is on A, the light is off. Having both switches set to the same wire completes the circuit.",
"Imagine that you want to call a friend. You have two telephones, A and B, and your friend also has two telephones, A and B. The A phones connect to each other only, and the B phones also connect to each other only. To talk to your friend (to switch on the light in this analogy), both of you must pick up the same letter phone. If both of you are holding the A phone, you can talk to each other (the light is on). If any ONE of you switches to the B phone, you can no longer talk to each other (the light is off). So, when the light is on, either switch will turn it off. If you are holding the A phone, and your friend is holding the B phone, you can't talk to each other (the light is off). In this case, all it takes is one of you to switch phones. If you switch to B, you can talk! If your friend switches to A, you can talk! So you see, when the light is off, either switch will cause it to come on."
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klkwyl | Why do softwares require us to restart our devices. Why wont a shut down do the same work as a restart. | Technology | explainlikeimfive | {
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"Many updates make changes to programs that are already running - these programs are already in your RAM. The updates only change the programs stored in long-term memory. Restarting your computer causes the RAM to be cleared and the updated version to be initialized into RAM instead. A shut down works just as well as a restart, but most of the time they assume that you're going to want to keep using your computer after the update; something which you cannot do if it is turned off."
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kln9q9 | how do changes in screen resolution work? | On the Galaxy S9 for example, you can change to 1080p down from 1440p to save power. How does this work, becuase from my understanding, the screen is made from millions of individual LED bubs that each form a pixel (2960x1440) 4,262,400 to be exact. You can't just turn a few off and expand the others, they're fixed, and when you put it in 1080p mode, it's still full screen, so it's not just using a portion of the screen | Technology | explainlikeimfive | {
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"It's not just the pixels lighting up that consumes energy you also have to compute the image itself that the pixels are displaying. And the more details that entails the more costly the operations to compute it whereas if large chunks of the screen don't need to be computed or be turned on/off or changed that on it's own saves some energy."
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klsc2m | How is an air fryer different than a regular or convection oven? | Technology | explainlikeimfive | {
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"An air fryer is the same thing as a convection oven so the only difference there would be the form factor. The way both work (compared to a normal oven with convection off) is with a fan to constantly circulate the air around whatever you’re cooking. Some ovens don’t have the convection setting at all. It’s not the default setting on ones that do because it’s often loud and uses more energy due to the fan. Plus, it isn’t relevant to many common dishes — a casserole isn’t going to be any different in a convection oven.",
"There is still an important concept missing from the other explanations. Oil plays a large role in how an air fryer works. To start, let's look at how an oven, convention oven, and deep fryer work. An oven and convection oven both cook food by heating air and having it circulate around the food. Convection ovens use a fan to move air around, but a regular oven doesn't. However, a deep fryer uses an electrical heating element to heat oil. The oil is hot enough, and contains enough energy, to cause the water in the outer layer of your food to flash into steam. This is how fried foods get a nice crunchy crispy exterior. Onto an air fryer. Instead of heating a giant container full of oil (which can be really dangerous and generally splatters badly when food is added to it), a small amount of oil is added to the outer layer of a food. A quick shot of cooking spray is sufficient. The air fryer then uses circulating hot air to heat the oil, which in turn heats the food. This is how it fries foods. Without any oil, it's essentially a convection oven.",
"In honor of it being December... A standard oven is like sitting in your car with the engine off on a cold winter day. A convection oven is getting out of that car and discovering that it is windy and the wind is cutting through your jacket. An air fryer is you walking to get out of the parking lot and going between two tall buildings that funnel the air. Now the wind is absolutely howling as it rips past you... and then the freezing rain starts. Its basically that, but for hot instead of cold.",
"It’s not, which is why the New York Times review site - Wirecutter - says [The Best Air Fryer is a Convection Toaster Oven.]( URL_0 )",
"* It's much smaller. * That's about it. * They are useful if you want to cook a small batch of something. * Also because they are small they take less time to heat up and use less energy when compared to a normal sized convection oven.",
"I would argue the smaller size and bias towards adding oils when using one leads to faster cooking times and often better crusts. I'm amazed at salmon in mine versus the full size convection oven. The smaller size makes even cooking a lot easier, or so it seems. It really is just a convection oven. A lot of people swear by the difference, myself included, but scientifically there shouldn't be."
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kluciy | How does a virtual machine (like virtual box) work? | I was looking for ways to develop iOS apps using my windows computer, and I came across this option. I understand that you’re running a Mac OS on a pc, but I dont really understand how it’s different from a hackintosh. I read somewhere that using a virtual machine was like running two computers at once on the same physical computer but I’m not sure that makes sense. | Technology | explainlikeimfive | {
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"Takes a chunk of your RAM and makes it think it's a small computer with ram of its own, then you install an OS onto that mini computer inside your RAM."
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klw0ls | How do blood oximeters calculate one’s blood oxygen level by just being placed on a finger for the pulse? | Technology | explainlikeimfive | {
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"I'm guessing you've stuck a flashlight under your palm or your finger so you could see the other side of your hand light up bright red. Oximeters work on a similar principle. Oximeters have a light on one side and a sensor on the other. When light strikes the molecules in your blood on its way through, it passes on energy and those molecules get excited. Molecules don't like that so they expel that excess energy. Here's the cool part, that energy gets expended as light but different materials (oxygen molecule or iron molecule) get rid of that light as different colors (sort of like how fireworks get different colors by burning different materials). If we know the color of the light going into the hand and the colors going out, we can use some handy formulas to figure out what percentage of your blood has oxygen bonded to its red blood cells. Edit: I'm getting a few corrections in the comments. This is not a complete answer, it's the ELI5 to demonstrate a principle at work. Spectroscopy is awesome stuff as is optics in general. If you're interested, go study up and see all the cool stuff they're doing.",
"[A fantastic explanation]( URL_0 ) from the Technology Connections channel.",
"They pass a light through your finger, and the color that makes it to the other side is dependent on the oxygen content of your blood. A little math to get a percentage, and presto, you've got some biometrics.",
"I actually worked on this for my senior project in undergrad electrical engineering. In the device they put on your finger, there are two flashing LEDs. One is red and one is infrared. They flash in an alternating fashion very quick. So quickly, that you think the red light seems on constantly to the naked eye. On the other side of your finger is a sensor that detects the amount of light being transmitted through your finger. You only need 1 sensor to detect the two lights. Because the software controls when to turn on red or infrared at a known frequency, the hardware/software can determine when the sensor is seeing the response from the red led or the response from the infrared led and extract two readings. Based on the transmission ratio of the red and infrared light, it corresponds to how much blood oxygen you have. There’s a formula and a lookup table to figure out the level based on these two readings.",
"Few incorrect facts in this thread. I have attempted an ELI5 with a more indepth explanation in parentheses. The \"blood oximeters\" (pulse oximeters) shine 2 slightly different lights (wavelengths of 660 and 940nm). This light then passes through your finger and the detector on the other side calculates how much less light is received. [Blood that carries oxygen molecules \\(oxyhaemoglobin\\) absorbs more light more at the 660 colour than blood not carrying/carrying less oxygen molecules \\(deoxyhaemoglobin\\). The opposite is true for 940 colour.]( URL_1 ) [The computer in the device then calculates the amount of the overall absorbed light which is due to blood in your arteries \\(henceforth \"pulse\" oximeter\", because blood in your arteries is pulsatile. Nail, skin, soft tissue, venous blood for the most part are all non-pulsatile and will absorb a constant amount of light over time. This is done by the application of Beer-Lambert's law and the ratio of AC/DC\\). This will give you a number called R.]( URL_0 ) Now the computer has a database of what oxygen level (SpO2) someone has for a given number of R. How did it get this? Well it's because the manufacturer has done previous experiments on healthy volunteers where they breathed low oxygen air (FiO2 < 0.21) and took blood samples (ABG to find out SaO2) at each R, down to a reading of 70% (values of 50-70% are extrapolated because a semi-linear relationship). Now there are things that can mess up your reading on the blood oximeter: [Blood that carries carbon monoxide absorbs light similarly to blood that carries oxygen at both colours, and hence this cannot be detected on our machine.]( URL_2 ) Blood that has \"poorly working\" haemoglobin (methaemoglobin) due to certain conditions will produce an R value that corresponds similarly to a reading of 85%. Similarly, certain dyes that are injected for medical procedures (e.g. methylene blue) will give a reading of 85%. For the above problems, we can use machines that have additional wavelengths of light (4+) to account for these discrepancies and give a truer reading. Edit: comments that suggest that dark skin/dirtiness/nail polish/etc will affect the readings are only slightly true. As long as you have sufficient light passing through the patient, and the light emitted is constant (i.e. no movement, no additional light sources), you will get an accurate reading (as the CPU will take into account the pulsatile component of the overall absorbance). Edit2: also forgot to mention that the reading it gives you is not instantaneous, but an average over 10-20 seconds! This is why it can take a bit of time after putting it on before producing a number. It's also why certain heart rhythms can cause errors in your reading.",
"Okay so you know how you can see through glass but not through tables? And how x-rays also see through body but not through bone? You can do the same thing with oxygen rich blood (oxygenated) and deoxygenated blood. They use two different colour lights and see how much of each type is absorbed then through the magic of maths calculate how much of your blood is oxygenated vs deoxygenated! A rudimentary pulse oximeter can be built for like less than $ 20 If you [Google around]( URL_0 )",
"Remarkably, you can see an oximeter in action in the film *Dive Bomber*, made in 1941! Built earlier that year by a physiologist named Milligan, it used incandescent lamps instead of laser diodes, and its data readout took up one whole wall of a lab, but it yielded useful information on the problems of dive bomber pilots during WW2. It was four decades before an ordinary medical practice could afford an oximeter, and one more before personal units came out, but SpO2 quickly became known as the \"fifth vital sign\" (after pulse, temperature, blood pressure and respiration)."
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klxiwv | Why does hitting a TV remote often get it to function when it wasn’t working before? | Technology | explainlikeimfive | {
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"As you know, your remote is powered by batteries. Those batteries complete an electric circuit, which lets electrons flow from one end of the battery, through the remote, and back to the other end. During this process, the electrons passing through the contact springs and the batteries' tailcaps deposit a very, very thin layer of corrosion/oxidation (more so as the battery's charge runs down), which breaks the circuit. Smacking the remote jostles the batteries slightly, breaking this layer and restoring the completed circuit. You can also achieve this effect by removing the batteries and popping them back in."
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klxo99 | Why do they push 5G so much instead of improving 4G coverage? I'm getting 200mbit/s on 4g and I could happily use my phone with a tenth of that. Where exactly are the benefits? | Technology | explainlikeimfive | {
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"5G really has a lot more to do with the business and commercial side of things, for consumer mobile phones, they only thing you'll see is increased speed. 5G for businesses though is going to be game changing--not might be, it will be. For consumers mobile phones though, do you really need more increased speed? The answer is, well, not really right now, maybe in the future, but not really, but they've got to sell it to you somehow, even though the network is really more being built for businesses. The issue with \"improving 4G\" is that there really isn't any reason to keep investing in this technology when its almost entirely built out. Instead you're better off maintaining 4G LTE which will live alongside 5G, and build out your 5G networks (and to be clear 5G is a collection of things, that collectively is called 5G not just like one thing) Now one of the problems with 5G is rural areas. 5G signals and technologies really don't work well over distance, they work best in densely populated areas, like major cities. There's also more there... thats where these companies can make the most money. Building rural mobile networks just isn't anywhere near as good a business decision as building out a network in Dallas or London or Tokyo. Urban/rural divide with regards to 5G technologies is going to be quite significant.",
"Simply put, just because **you** don't see a need for 5G speeds doesn't mean no one does. Some people might not even have Cable or WiFi plans anynore and instead use hotspots with high data mobile plans. With things like Stadia people will increasingly start streaming games on mobile devices. 4 and 8K video streaming, people working mobile with laptops who might have to transfer large amounts of data to and from their company servers if they work remotely.... There's plenty of cases where it might be nice to have the added speed of 5G, even if you can't think of any",
"Our technological advancement has always been pegged to our ability to send information from one place to another, faster, better and cheaper. Today you can stream movies and tv on your phone seamlessly. That would have been completely unimaginable to someone operating on a 1G or 2G network. So completely unimaginable that the thought of even using your phone for something like that would never have even crossed your mind. Likewise, the upgrade from 4G to 5G will enable newer technologies that will require those speeds. Some examples that will require 5G networks: - Video game streaming - AR and VR applications - Self-driving vehicles - Large Internet of Things (IoT) networks These are just consumer things, but there are a lot more industry applications.",
"> Is this just marketing There *are* some advancements, but...yeah. The craze was the same with Edge, 2G, 3G, 4G, etc.",
"5G is better at handling large numbers of devices all trying to use the same network equipment. So it helps in areas like cities that might have excellent signal strength, but the towers providing the signal are constantly overloaded. If you’ve been to a sporting event or similar you may have experienced a loss in cell service due to too many people using the network in the same place. 5G should be more resistant to this."
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klxr9p | Why is the video editing greenscreen... green? | Why is it green and not red or blue or anything else? | Technology | explainlikeimfive | {
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"You need a bright primary color, one that most people aren't going to wear or have on their bodies, because all of that color will be deleted when you edit the film. You can use blue, but green is less likely to cause problems with people's eyes or fashion. Red is worst, because it can cause problems with erasing some people's skin tones at times.",
"Because green is the colour channel with the highest resolution. In a Bayer filter, which all modern cameras use, half of all photosensors are green light sensitive with only a quarter for red and blue respectively. This means that the green channel has effectively twice the resolution of the blue and red channel, making it ideal for this kind of work.",
"Short answer is because other things in the frame are never that color green. For a green screen to work the screen must not be the same color as anything used in the shot.",
"Because bright green is the color least likely to be in the foreground you're filming, so there's less risk of it being mixed up with the things in front of it. Red, in particular, runs the risk of being confused with the shades of human skin. Blue is in fact sometimes used, but green tends to be preferred because blue is more common in clothes (e.g. jeans).",
"You want a colour that can easily be distinguished from others in frame. It's a long way from skin tones, and most clothes. Gree is not a widely used colour in most things that might be in the foreground of a shot. THe only issue with it is if you're trying to film plants, but they're rarely part of the foreground, and if they were you can simply use a different colour screen. There's nothing special about green."
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km2nez | Why do some low-range smartphones have better battery than high-range ones? | Most of the newest smartphones of high-range (e.g., Xiaomi Mi, iPhone, Samsung and Huawei) that cost over $500 have 4500 mAh approximately or some even less, but for example, the Redmi 9 (costs less than $200), that is considered low-range has 5020 mAh. Why those top smartphones don't have a better battery than some of those low-range? | Technology | explainlikeimfive | {
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"High range phones come with an expectation for more features, higher end materials and less weight. When you add all those things together you have less scope for space and weight so the battery size gets shaved down.",
"Keeping size and weight at a minimum is far more important for flagship devices than it is for entry/midrange devices."
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km6cvs | What does it take to make an everyday object programmable? Is it inserting a CPU in it? | Technology | explainlikeimfive | {
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"TLDR: no, cpu doesn’t exclusively mean programmable Let’s start with “stick a CPU in it.” If you took a CPU and stuck it in a marshmallow, is the marshmallow now programmable? No, because simply sticking a processor in an object does nothing. Conversely, there are lots of objects that are programmable that don’t need a CPU. A mechanical music box is a great example of this. If you change the pinned wheel, you get a different song. What makes a music box programmable and a marshmallow not? Well, let’s look at what’s music is: a set of instructions to Do A Specific Thing At A Specific Time. The gearing makes sure the pinned wheel moves at a fixed (ish) speed, and the pins engage the tuned teeth. Each tick of the gears, a new thing happens: either “proceed” or “proceed and hit tooth X”. Making anything programmable requires breaking down what it does into simple steps that can be reproduced with machinery, be it mechanical like the music box, electromechanical like an old Wurlitzer or a pinball machine, or electronic. What does it take for a toaster to be programmable? Break down what a toaster does: bread goes down, elements heat up, bread goes up. So at a minimum, you need to a) identify when to start, either by actively pushing the bread into the machine or flipping a switch to make the toaster do so; b) turn on the heating elements for a certain amount of time; c) turn off the elements when the time is up; d) get the toasted bread out of the machine. (Obviously I’m oversimplifying.) You can program a small computer to do this, but you can also use analog signals to do the work. For example, you can have your processor count down 120 seconds, but you also could have a simple thermocouple, two pieces of different metals that expand differently under heat, turn the toaster off when it gets “too hot” by breaking an electrical connection.",
"The ability to encode a series of instructions based on input and respond with outputs based on said input. Or put another way, a machine that makes a thing do something based on another thing doing a thing"
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km8nd9 | What goes on during cyber wars across countries? | Technology | explainlikeimfive | {
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"text": [
"Well a cyber war wouldn’t necessarily mean you wouldn’t need to use conventional weapons/war as well. World war is unlikely to happen due to nuclear weapons. But I can’t imagine something that could be called a cyber war, more cyber attacks/defence. And yes there are countries that work together, think the 5 eyes of uk, us, aus, nz, and can, it’s an intelligence sharing community but I doubt they wouldn’t work together on cyber attacks etc. Cyber attacks could replace the need for certain wars though, take for example the Iranian nuclear missile cyber attack by the US. If they were close to making nuclear weapons a conventional war could’ve been necessary, instead they managed to attack the centrifuges in the uranium enrichment centres using a virus, which destroyed a lot of their capability.",
"> I’ve read somewhere that a world war will not happen anymore because there are constant cyber wars. The main factor preventing world wars is the globalization of economies. Anyone starting a war will not only ruin trade relations with their target, but likely provoke their business partners into imposing economic sanctions > What goes on during cyber wars across countries? Mostly espionage. Countries try to gain intel on rivals and or carry out sabotage. For instance, the US made a virus that spread to Windows PCs indiscriminately, but didn't do anything nefarious except check if the PC had control over a specific type of motor known to be used by Iran for purifying nuclear material. Then the virus would randomly speed up those motors past what is safe, causing explosions on any such motors being used to refine nuclear weapons. This set back Iran's nuclear program considerably. > Are there certain countries that work together and attack other countries? While this is possible, I don't consider it likely. Unless one country is a satellite country of the other (basically subservient to the bigger country). Working together on a cyber attack is likely to tip one country's hand to the other's spy network, which is something they'd otherwise place a high priority on keeping secret."
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kme300 | How did they build the retaining stone walls along river banks in cities hundreds of years ago? | Struggling to explain what I mean, every major city/river/harbour doesn't have a natural coast line, but generally a stone wall that goes down into the river and creates a permanent solid edge. I'm sure with modern technology its easier, but the ones built hundreds of years ago baffle me. Tried googling it but got a combination of Minecraft, retaining wall and river rock information.. | Technology | explainlikeimfive | {
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"5yo version: There's a few ways. One way is that they build a wall in the water where they want to work and then use buckets to take out all the water. So they can work on dry ground. Another way is just dump stone and earth into the water where they want the wall and then when it's shallow enough they build a nicer wall above water. As others have mentioned, they could also divert rivers, but you can't really divert the ocean! The chief exception being the sea dykes in Denmark! Here's an awesome animation of how it was done: [ URL_0 ]( URL_0 )",
"A Cofferdam is what you are looking for. Used in lots of situations like you mention. URL_0"
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kmmqb6 | How and why are 'rays' harmful? | Referring to all types of rays: electromagnetic, gamma, alpha, beta, etc. | Technology | explainlikeimfive | {
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"text": [
"Alpha/beta/gamma (ionizing) radiation is harmful because it can change the properties of atoms it hits, turning them into different elements or otherwise destabilizing them which in turn changes their properties. This can create changes or unreadable errors in DNA, or disrupt the functions of proteins. I'm less sure about electromagnetic radiation, but I believe the vast majority of the EM spectrum is harmless. Not my field, though."
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kmn8y3 | What's the difference between UTF 8, 16 and 32 | I'm learning the basics about computers and got to see about Unicode. Apparently it can be divided in 3 with UTF (Unicode Tranformation Format) which would be UTF 8, UTF 16 and UTF 32. I understand that each one has different value UTF 8 - 1B; UTF 16 - 2B; UTF 32 - 4B. But I don't understand beyond how much space each one of them takes what's the difference between one and the other? Also, apologies if I got any concept wrong :$ Feel free to correct me if I did | Technology | explainlikeimfive | {
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"Unicode assigns a number to every possible character. However, it doesn't dictate how these numbers are represented as bits - that's what UTF-8/16/32 do. In UTF-8 the base unit is a single byte. Numbers from 0 to 127 are stored as a single byte, numbers from 128 to 2047 are stored using two bytes, numbers from 2048 to 65535 take 3 bytes, and from 65536 and above they take 4 bytes. Meanwhile, in UTF-16 the base unit is 2 bytes, which means each character either takes 2 bytes or 4 bytes (the actual encoding is a bit more complicated than UTF-8). Finally, UTF-32 is a fixed width encoding - every character is simply encodes using a 4-byte integer. UTF-8 is backwards compatible with ASCII and is therefore most efficient if you're mainly using Latin letters. UTF-16 is more efficient when you're using multiple languages.",
"Unicode is a system that is designed to encode every character in any language. Every character is represented as a code point, which is just a number from 0 to 1,114,111, or U+0 to U+10FFFF in hexadecimal. (Not every code point is a character- some correspond to accents that combine with other characters, etc.). UTF-32 is the simplest encoding, which just stores the code point as a single 32-bit number. So the code point U+1F600 (a grinning face) is just stored as the hexadecimal 0x0001F600 (which is actually stored as 00 F6 01 00, on a typical \"little endian\" machine). The advantage of UTF-32 is its simplicity, as every code point is the same size. But it wastes a lot of space (many of the bits are always zero, and many of the rest are almost always zero). UTF-16 represents every code point as either 16 or 32 bits. All the code points from U+0000 to U+D7FF and U+E000 to U+FFFF are encoded as 16 bits in the obvious way (i.e. U+E000 is just 0xE000). The higher code points (U+010000 to U+10FFFF) are split into two surrogate pairs. First the code point has 0x10000 subtracted from it, and then the resulting 20 bit number is split in two. The highest 10 bits are attached to a number beginning with the bits 110110 and the lowest 10 bits are attached to a number beginning with the bits 110111. Then these two numbers together make the whole encoding of the code point. So, instance, the code point U+1F600 would be encoded like: - Subtract 0x10000 to get 0xF600 - Express 0xF600 as a 20-bit binary number (00001111011000000000) - The first surrogate pair is 110110 then the first ten bits (1101100000111101=0xD83D) - The second surrogate pair is 110111 then the next ten bits (1101111000000000=0xDE00) So then the grinning face would be encoded the two 16-bit numbers 0xD83D and 0xDE00. (On a little endian machine, this would be 3D D8 00 DE in memory). UTF-16 lacks the advantages of *both* UTF-32 and UTF-8. The only advantage it arguably has over UTF-8 is that for certain languages it can result in smaller encodings. But it is complicated, and a major source of bugs in supposedly \"Unicode compliant\" code. Unlike UTF-32, it is not a fixed-width encoding, but many bugged code treats it as fixed-width and breaks when higher code points are used. In UTF-8, each code point is stored in 1 to 4 bytes. Every byte in UTF-8 corresponds to one of the following patterns - 0xxxxxxx One byte code point - 110xxxxx Initial byte of two-byte code point - 1110xxxx Initial byte of three-byte code point - 11110xxx Initial byte of four-byte code point - 10xxxxxx Non-initial byte of any code point Looking at the above, one-byte encodings can hold 7 bits of information, so they correspond to the first 2^7 code points (U+00 to U+FF, ascii characters). 2 byte encodings can hold 11 bits (5 in the initial byte and 6 in the following byte). 3 byte encodings can hold 16, and 4 byte encodings can hold 21. In theory, there is room for more, but with just these options UTF-8 already holds more room than UTF-16 does. The same grinning face emoji (U+1F600) would be encoded as: - In binary, the code point is (11111011000000000). This is 17 bits, and so only fits into a 4 byte encoding - Pad the code point to 21 bits (000011111011000000000) - It's a 4 byte encoding, so the initial byte is 11110xxx - Take the first 3 bits and put them in the initial byte, to get 11110000=0xF0 - Then the next three bytes are 10xxxxxx. Put six bits in each one: (10011111=0x9F,10011000=0x98,10000000=0x80) - Then the grinning face is encoded as 0xF0 0x9F 0x98 0x80. (Regardless of endianness this is F0 9F 98 80 in memory). UTF-8 has many advantages. It is backwards compatible with ascii, and a lot of code and libraries written to work with ascii text will just work with UTF-8. It is always smaller than UTF-32, and in most realistic situations it's also smaller than UTF-16. It's simpler and less prone to bugs than UTF-16. The encoding does not depend on whether the machine is big endian or little endian. It is self-synchronizing. This means that, since the initial byte of a code point can always been told apart from a following byte, if some bytes are lost somehow it doesn't corrupt the whole thing, since a program can just skip ahead to the next initial byte and start reading again. If you are a developer, what you need to know is mostly: - Use UTF-8 if you have any choice in the matter"
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kmnla4 | How do logins instantly know our credentials are incorrect whereas it takes a little while for correct credentials to be validated? | Technology | explainlikeimfive | {
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"text": [
"They don't. Validation or failure both take the exact same amount of time. Perhaps the issue is that, wherever you feel you are experiencing this, a failure is able to send a simpler failure message than a success, which presumably then has more to do since after you validate, it then needs to load whatever you were trying to access in the first place.",
"It takes only one check to validate the credentials. Once they are valid much more work is done on the server to actually complete the login process and establish the session."
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kmnnsc | How do email and video conferencing work? | What really happens in the background that the users don't see, that magically makes GMail send emails and Zoom make video conferencing possible? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Your question is quite a broad one. Email and video conferencing are completely different technologies. There are also many variations within each technology. Email for example can use many different protocols such as SMTP, IMAP, and POP3. If you're looking for a succinct ELI5 answer, you're going to need to narrow the scope."
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kmsvgc | how do sound equilizers work? If there is only one audio file, how do equilizers differentiate between bass, minds, and things like that and then are able to change them? | Technology | explainlikeimfive | {
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"text": [
"There is math called a \"Fast Fourier Transform\" that can take any sound (wave) and break it into separate frequencies. As a simple example, imagine an audio file where two flutes are playing in harmony. The FFT of that file would clearly show the frequencies of the two different sounds, even though they were combined into one wave. Now, say the lower-sounding flute is a little too quiet - the same math (mostly) can be applied to make the lower frequencies louder, without changing the higher frequency sound. Congratulations, you just raised the bass. Now, instead of two flutes, think of doing this math across three flutes with bass, mid, and treble. Finally expand this into a lot of different frequency bands and you have a full EQ. I have no idea how to ELI5 the FFT itself, so just wave your hands and say math magic.",
"It turns out you can build electronic circuits that can filter audio based on a range of frequencies. For a simple 'Low/Mid/High' EQ there would be three filters. One would filter out everything higher than a certain point. Another would filter out anything lower than a certain point. The last one would do the opposite of the other two. So now you have the entire range of audio frequencies but it's split into three separate audio signals. At this point you can adjust each signal up and down. Then the EQ mixes the signals back together. When it comes to digital audio the same thing can be done except it's done with clever math instead of physical electronic circuits."
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kmt32o | How do different USB types allow better data transfer rates? What is actually happening? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The USB 3.0 standard introduced new connectors that had 5 extra wires: 4 of these pins were reserved for 2 new data pairs , allowing full duplex communication, (a huge increase from the single pair on the previous connector). The type C connector optionally has two more data pairs, used by USB 3.2 gen 1x2 and usb 3.2 gen2x2 (10 and 20 gigabits per second, respectively)"
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kmuh42 | How do some seven-segment-displays shine black? | I read that they use LEDs, but black isn’t really a color you can shine. It’s the lack thereof. When black is displayed on a monitor, the pixels are just left unlit. However, black seven-segment-displays turn noticeably blacker in activated regions. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Black digits like on an old calculator? Those are early liquid crystal displays. When unenergized light passes through the segment. When energized the crystals align to block the ambient light from passing through. They don’t emit black. They just block light from passing.",
"Think about it like drawing on a mirror with a marker. The light is reflecting off the back and being blocked by the marker as it comes towards your eye. If it has an LED backlight it’s a flashlight behind glass."
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kmw85q | Why does HDTV look so strange and "fake"? | Technology | explainlikeimfive | {
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"text": [
"It sounds like you're referring to the \"stage effect\" caused by some of the clarity and smoothness filters. Those are post-processkng effects applied by the TV itself in order to \"upscale\" the picture by filling in details that aren't there. The final result ends up being so clear that it looks unnaturally so to the human eye.",
"It may depend on what you're watching. For example, when The Hobbit trilogy came out, it was released in HFR (high frame rate, 48 fps). I made sure to watch it in that format in the theaters, not because it's better, but it's something you don't see every day. And you feel like you're watching a stage production with the best effects crew in history. It doesn't feel like a movie AT ALL because of the HFR, and I think that messed with people. The internet is full of people who did not like the HFR thing for The Hobbit. We have expectations going in of what we want to see. 24 frames per second, some motion blur, etc. In the 80's there was a huge difference between what regular TV shows looked like and Soap Operas because they shot on video (which had a slightly higher frame rate and handled lighting differently). In most cases, it looked more real, less cinematic. I'm not saying this is the answer to your question, but I'm taking that stab at it. Ask yourself this question: Do you watch sports in HD? Do you prefer that for live events? If so I'm guessing that you, like a lot of others, have these hidden expectations of what you're used to seeing.",
"I read somewhere that it is all staged and fake. It really took the fun out of watching it for me... I'm sorry for ruining it for you now too."
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kmws1z | Japan plans to make wooden satellites to eliminate waste in space. What happens to wood in space? Is this a good idea? Is it possible? | Technology | explainlikeimfive | {
"a_id": [
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"The company planning to do this never said that they were doing it to decrease space junk. And indeed, wooden satellites will not contribute to decreasing space junk in any way. The news was misinterpreted by most news agencies (perhaps intentionally) because space junk is a buzzword. What the company is actually trying to do is to decrease accumulation of heavy metals in gaseous form in the upper atmosphere. This is because when satellites deorbit they burn in the atmosphere and those metals are released, which are bad for the environment. But even this is doubtful, because most of the heavy metals are not in the structure of the satellites (which is going to be replaced by wood) but deep inside. So all in all this is very likely (but not definitely) a publicity stunt by this company, which is succeeding. In regards to whether this is possible or not, I would say yes, sort of. It is definitely possible to build wooden structures for small satellites but I am not sure about the big, geo-stationary satellites."
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kmxyxb | At what point, and how, does computer hardware touch/move/influence the software? | Technology | explainlikeimfive | {
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"text": [
"Software is usually just a list of instructions for the CPU to do, and the CPU just runs those instructions. Sometimes there is instructions for the graphics chip/card, or sometimes those instructions tell the operating system to write to disk. But it’s still just a list of instructions the cpu knows how to execute. Excellent video on how these instructions look if you are interested: URL_0",
"Depends on how you think of software. Really the distinction between software and hardware is only useful for us humans to simplify the concept of how a computer works. Like the laws of physics, it breaks down once you put a microscope to the low-level mechanics of it all. If you define software as, the data and applications stored on a medium like a ROM chip, a disk drive or a DVD disc, then this happens constantly. Initially when the computer boots it (more specifically, the CPU) is designed to load instructions from the BIOS. During the boot process the other hardware is initialised, which in turn will load up its own software usually from some kind of ROM. The network processor loads its initial instructions from ROM then awaits further instructions from the CPU, as do the sound processor, graphics processor, etc. These instructions could all accurately be called software, though we tend to use special names for them like \"firmware\". Even the CPU itself has its own special firmware that is called microcode. Eventually the BIOS tells the CPU to load further instructions from the boot drive (which could be a hard disk, an optical drive, a USB drive, a network address...). From there the operating system is loaded which triggers all kinds of software interactions - applications and services to be loaded, log files to be written to etc. Once you have a loaded operating system, typically you are waiting on the user to provide further input. Ultimately they end up telling the CPU to store some software on a drive or in memory and/or execute it. So to answer your question, the \"when\" is, basically from the start of the boot process and then constantly thereafter; and the \"how\" is, it's either something the components were hard-wired to do, or it's something they were told to do based on instructions that were previously stored somewhere."
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kmzvdv | what do network switches do | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The basic principle behind a local area network is that any data packet sent out on the network should be delivered to all other computers connected to the network and they will then filter the packets based on the destination address. This is how early network equipment worked. The problem is that this is not very efficient as a single link can quickly become satturated with data packets that is just being discarded on the other end. The solution to this is to install network switches which try to make smarter decisions about where to send the data packets. The general rule is still to send out all packets on every link, however if the switch knows where the destination is then it will only send the package in that direction. This means that the network links can be used more efficiently increasing bandwidth in the network. Further on switches will now usually switch not only based on the address of the data package but also on a virtual LAN tag configured on each port. This means that a single switch can act as multiple switches on different networks and that a single computer might have multiple virtual network interfaces on different networks using a single physical link to the switch.",
"Suppose you want to connect a bunch of computers together. There have been many ways of doing it. You can have a single cable, with taps on it for each computer. You string a long cable through an office, and then attach connectors at the right places. Cheap cabling-wise, but very inconvenient. If the one cable breaks, lots of people have trouble. And you can't really move equipment around easily. You can have a ring. Each computer has an input and an output that plugs into the next computer on the line. This also has issues, every computer on the line has to work properly, or the network breaks. Or, you can connect computers to a central point. That's what a switch is for. Each computer connects to the switch and the switch connects to everything. So when computer 1 wants to talk to computer 20 the connection goes 1 - > switch - > 20."
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kn3aod | why the energy saver program on my washing machine takes the longest ( > 4 hours). | Edit: I mean a clothing washing machine | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Because it uses cold water to wash the dishes for more time, heating water is what uses most energy but can clean quicker."
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kn6p6b | How do phones (or any electronic device) measure their battery level? | Technology | explainlikeimfive | {
"a_id": [
"ghiptpm"
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"text": [
"Batteries use a chemical reaction to generate voltage (\"electric pressure\"). As the battery discharges it consumes the reactant chemicals and builds up product chemicals, which leads to a slow but predictable drop in voltage. The exact voltage curve varies with the battery chemistry and design but, as long as the device knows what the curve looks like, it can directly measure the battery voltage and \"translate\" that to how much the battery has been discharged. This method gets out of whack if you put a really huge power draw on the battery (for example, it doesn't work on car batteries while they're starting the car) but electronic devices typically are a relatively low draw for a period of hours, not a huge draw for a few seconds, so the difference between voltage under load and the \"true\" voltage (called \"open circuit voltage\") is pretty small. Here's a selection of voltage curves: [battery voltage curve - Bing images]( URL_0 )"
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kn781w | Why do most of the heavy machines use diesel instead of petrol? | Technology | explainlikeimfive | {
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"Diesel engines are more efficient because of their higher compression (it's true that diesel has slightly higher energy density too but that's not why diesels are more efficient), they produce much more torque at low speed, they are far more efficient at part throttle, they're electrically simpler, diesel is a safer fuel, and they're generally more durable. The things diesels are bad at (low weight, fast acceleration, high RPM) generally don't matter for heavy machinery so it's an application where all diesels' advantages help and the disadvantages don't really hurt.",
"Diesel engines produce more power from less fuel, because diesel has more energy available per gallon. Diesel engines are also built more ruggedly, and their mode of operation requires less maintenance than a similar petrol engine.",
"Heavy machines require a lot of torque to operate. Torque is best created with engines that have high compression ratios. High compression ratio‘s require fuel that has a high flashpoint. Diesel has a much higher flashpoint than petrol.",
"In addition to the power density, diesel engines are mechanically simpler than gasoline, the fuel doesn't form a vapor like gasoline and so storing, handling and use is safer with much lower chances of fire or explosions and the diesel engine has the highest effective efficiency of all combustion engines."
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kna8gk | What is the little clock-like symbol that’s on a lot of plastic products (and plastic containers)? | Technology | explainlikeimfive | {
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"It's a manufacturing marker. Shows the date (well, often it shows just a week or a month) when the plastic went into the mould. So that a faulty product can be backtracked to who inspected it, which machine did it, who supplied the raw materials. And so on."
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knbrjj | What determines which floor/direction an elevator will go to first? | Technology | explainlikeimfive | {
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"Elevator dispatch is an engineering problem, and there isn't one solution used everywhere. One simple algorithm is to make one trip up, one trip down, per cycle. Starting from the lobby, the car picks up passengers everywhere an \"up\" button has been pushed, stops at the floors requested (from inside the car), and then moves the the highest floor where a \"down\" button has been pushed. Then it travels down, picking up and dropping off passengers as needed, until is reaches the ground floor, and restarts the cycle. That's a pretty good program, subject to some assumptions: the car will never get overloaded (there just isn't enough traffic for the weight limit to come into play very often), most trips either begin or end on the ground floor, there are seldom two people on one floor who want to go in different directions, and so on. That's good enough for, like, a small hotel, but if you have a more complicated system, you might want to include logic like, *if sensors detect that the car is already at or near its weight limit, only make drop-off stops; don't stop for floor calls,* or *one car on the system should have its idle position be three-quarters of the way up the shaft, to reduce wait time on higher floors.* It takes thoughtful design.",
"I don’t really think there is one answer. I’d imagine the elevator company and building owner have some level of control over the floor priorities within the elevator program. So there is most likely a unique answer for each building."
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knia03 | Why do regular non micro wave ovens have non clear glass | I know micro waves have a metal mesh behind the glass door to stop radiation, but why do normal gas/electric ovens have dots on the glass instead of being crystal clear like a normal window | Technology | explainlikeimfive | {
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"ghkoakw"
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"If it were clear glass, the oven would lose a LOT of heat through the glass through radiation. This reduces the efficiency and also results in a temperature gradient (near the glass it would be cooler). The temperature gradient means things cooked in the oven would be unevenly cooked."
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knj07p | Why were older crt TV sets (circa 1935-1953) more rounded than newer ones, was it just aesthetics of the times, or did production process changed, or was it something different? | Technology | explainlikeimfive | {
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"ghksjo2"
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"Sharp corners cause stress fractures. CRTs are under significant pressure, and manufacturers wanted to make sure they didn't implode in someone's living room. Over the years, while CRTs were a thing, manufacturers got better and better at corners. They also got better at \"bigger\" so they could make the tube a little oversize to show a square corner in the picture. Some designer concepts, often called \"[googie]( URL_0 )\" used this rounded shape as \"futuristic\"."
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knjxrx | how do saw stops tell hands and other things apart from wood? | Technology | explainlikeimfive | {
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"The system is monitoring for anything that conducts electricity to touch the blade. If the wood you're cutting is _super_ wet, it can set off the sensor.",
"There is a small electric signal on the saw blade, when the saw hits skin the signal changes and it will stop the saw.",
"But that saw blade has so much inertia... it doesn’t do even a little cut to a body part?",
"I used to sell Saw-Stops at an old job, and the technology is fascinating. Two folks have great examples and the videos explain everything. But in short, you produce a bit of electricity that the mechanism that is attached to the blade can sense and will release a spring loaded brake into the blade. Like already said, wet wood and pressure treated wood will trigger this due to the moisture sending a signal to the device. Also, they are super expensive.",
"Saw blade has voltage going through it. When human sticks fingy into blade voltage lowers. Lower voltage activates saw stop ultra fast and saves fingy from getting cutty cutty."
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knk5m9 | Why does the video playback in video editing software require so much more computing power than watching the same video in VLC or Windows Media Player? | Not even talking about UHD raw footage from a movie camera, just like an exported MP4. What is it about the playback/preview of the video in a program like Adobe Premiere that bogs down my computer so much that it is unwatchable, whereas watching the same video on a media player is perfectly smooth? | Technology | explainlikeimfive | {
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"When you playback on editing software, it checks for user added content like text, animation or transition on the video and then plays back the frames. This processing is done for every frame of the video. So the video plays choppy and your frame rate drops. As you add more layers on the video in your editing software, the playback slows down. That's why video video editing software requires high powered processor also with more amount of ram. On the other hand the video players only has to show 1 single layer of video, so it plays smooth."
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knkmnj | How did people in medieval ages use candles on Christmas trees without causing major fire accidents? | According to history, people used candles on Christmas trees for decoration. And this was still practiced till the invention of modern day lighting. Lit wax candles on almost drying trees sounds like a serious fire hazard. How could people put candles on trees without setting the tree on fire? | Technology | explainlikeimfive | {
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"My grandfather worked for an insurance company back in the day; my mother said that every year they paid claims on fires started by electric lights on Christmas trees, but never one on candles. Because it's such an *obvious* fire hazard, people were super careful: Most of the family leaves the room. A few people light the (small) candles clipped onto branches; they have buckets of water and/or sand ready at hand. Turn down the room lights. The rest of the family comes back in and \"ooh\"s and \"aah\"s at the spectacle for a few minutes. Maybe sing a song. Then the candles are put out and it's time for dinner, or presents, or whatever.",
"When I was growing up we had real candles on the tree. There is nothing more magical then real candles burning on a tree when you are a child. It was only lit on Christmas eve for a few hours during the gift giving. Perhaps lit one more time on the evening of Christmas day but that was about it. No month long light show and the tree was not even put up until the morning of Christmas eve.",
"Some places still do it today. A little care and forethought (not putting a candle underneath a branch) goes a long way toward preventing accidents. Also, they’re only lit for specific times under supervision just in case a candle falls. All that said, medieval cities burned to the ground pretty regularly because there were open fires everywhere, indoors and out, and a ton of building were wood with thatched roofs."
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knkr1o | - How do robots dance? | We've all seen the new BOSTON Dynamics video with the robots dancing. Did they program it for that song? Or is the AI doing this on their own? | Technology | explainlikeimfive | {
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"I would think you'd create a library of moves for each chassis, which start and end in a kind of neutral position so you can chain them together in any order. Then the robot can just execute those moves in a random, or scripted, sequence for as long as you want. You could measure the tempo of a song, and then just tell the robot to \"dance at 152 beats per minute\" (so it knows how fast to execute moves) or if you wanted to get complicated you could have an on-board microphone that analyzes the music in real time to determine the dance tempo."
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knmwda | Why don't adblockers work on some sites (like Spofity) and work on most other ones? | Technology | explainlikeimfive | {
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"text": [
"Ad blocking is a game of cat and mouse. Advertisement people come up with new, smart ways to avoid detection by the ad blockers all the time. Sometimes they manage to find some ways to push the advertisement that cannot be easily detected or stopped. By the way, my ad blocker works very well on Spotify browser player."
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knn0b6 | How did telegrams work? | Technology | explainlikeimfive | {
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"text": [
"A telegraph is a wire with an electric current running through it. By using a switch the line can be broken, stopping the current, and reconnected again, resuming the current. By activating the switch for short and long periods of time a sequence of signals is sent that can be received at the other end of the wire by seeing if there’s a current running in it.",
"Telegraph companies would build stations and connect them with electrical lines. An operator at one end would be able to switch the power in the line on and off using a telegraph key. In the other end it would connect to a speaker or a recording device. Operators could then send signals between the stations, most commonly Morse code. Later on they would also get radios to send signals between stations without a fixed wire connection. People would then be able to send telegrams between anywhere with a station in the same telegraph network. You would write the message on a form and pay the telegraph operator to send it. They would send the messages between the stations until it reached the nearest station to the receiver and would then be typed out on a similar form and delivered to the recipient with a runner. The format is a bit special because the telegraph operators would take payment depending on how easy or hard it was to send the message. It is easier to send common words as the operators can send them at full speed without errors. Morse code does not have lower case or symbols either so telegrams are all upper case and without punctuation. It therefore became common to use the word \"stop\" to mark the end of a sentence."
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knnoos | When programmers create games, where do the designs come from? | Technology | explainlikeimfive | {
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"Usually, at some point early on, the code says something like \"load {path/to/imagename} as pic21\" which comes from a directory or packed-up resource, and loads that picture into a memory grid so that it can be used later with something like \"place pic21 at x,y on screen\". Occasionally, games will generate their own graphics by setting up a grid in memory and assigning pixel by pixel info, so there's no file loaded, but this is only done these days for retro games or very small things like cursors, since doing a photograph-sized image this way would be enormously complex. When you have a game that you can hear grinding and grinding and overheating your hard disk, it's busy loading a lot of images and graphic resources that it might shortly need to use. This is also why if you drive or fly very fast in some games, forcing them to load more and more graphics very quickly, they will crash.",
"You have a photo called photo.png A game dev places photo.png in gamefiles/photos. Later. The game dev writes some code that says. \"Hey! Place the file gamefiles/photos/photo.png at position x, y, and z\". This is the gist of it.",
"By loading the graphics from elsewhere. Someone creates the models, textures, graphics e.t.c and the programmers either write the command that loads those graphics in or more likely simply drop them in to their game engine and assign them to the relevant in-game object."
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knonmq | How do transistors work? | I'm trying to understand how Transistors work and what the difference between a PNP BTJ and an NPN BTJ (Excuse my bad terminology, I'm not a tech person). Currently I understand how a base has to be active for the current to flow from the Collector to an Emitter in an NPN, however I'm unsure of how a PNP functions. I understand that previous posts may have asked this question, but none have answered specifically what I am asking. Thank you in advance! | Technology | explainlikeimfive | {
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"text": [
"They function like a water hose with a weight on them pinching them shut. The water hose is the connection between the Source and Drain. By applying a smaller current to the Gain you effectively lift the weight, which causes the hose to let more current through. Transistors are very precise and fast in this, so you can turn a small current change at the gain (for instance, caused by a microphone), to a very large one at the source (for examle, a current that passes through a loudspeaker). NPN or PNP stands for Negative-Positive-Negative or vice versa. These are functionally very similar, but the flow of the current is reversed - IE, for an NPN transistor, applying a positive electric charge to the gain \"lifts the weight off the hose\". For PNP it's a negative charge."
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knpmej | Why does website content often shift and move just after loading? | Technology | explainlikeimfive | {
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"Fun fact, the technical term for this is \"cumulative layer shift\", commonly referred to as CLS. It's a known problem, and Google will start to include CLS ratings as part of its website quality scores. They've been on a big push recently to improve user experience.",
"That can happen for example when the web developer who created the site was, well let's face it, bad. For example imagine the site has some headline, then a large picture and then some text below it. If the loading of the picture takes longer then the user will first see the headline directly followed by the text and starts reading. Then after a while the picture is loaded inbetween headline and text and thereby pushes the text down, disrupting the reader. An easy fix for this would be to set the dimensions of the picture beforehand and possibly load a low resolution version of said picture first. So basically this shifting usually happens when the size of the content changes, which is mostly due to naive implementations by the developer.",
"Web developer here. Simple explanation is that images load much slower than text, if the height/width of the image(s) were not defined ahead of time, then your web browser has no way of knowing how much space to allocate to it until after the image loads. Which is why text \"shifts\" as each new image is rendered. However, you can define the height/width that an image will take up ahead of time, which allows the browser to allocate the space for the image before it actually loads, thus preventing all that jumping around. So why don't websites do this? Well, a lot of it has to do with something called \"responsive design\". A website needs to be viewable across everything from widescreen 4k monitors to small handheld smartphones. Depending on the device you are using, images on the page could be scaled larger, smaller, in a different location, or not at all. This makes it much more difficult to determine what dimensions to allocate for each image ahead of time. It could be done, but would would require more computational processing on the back-end before the page is loaded, which means the page would load slower. Slow page loading is bad..."
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knpzn8 | Why is it that when you press firmly on your PC's monitor it leaves marks? | is it like.. heat marks or do you temporarily kill some pixels.. do you prevent electricity from getting to the monitor? what exactly happens there? | Technology | explainlikeimfive | {
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"LCD stands for liquid crystal display. When you press on the display you are forcing the material to flow, disrupting the illumination effect.",
"Answer : The thickness and perfect alignment of various light filters and light producing elements must be just right to produce the intended display. Temporarily disrupting the highly engineered thickness/alignment will mess it up - as well any water droplets or oils from your hand, which can create a concentrated lensing effect, like mini glasses for certain pixels"
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ko00k8 | Why does software like Adobe Flash have to be actively supported? Are all software like that? | Technology | explainlikeimfive | {
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"The flash player plugin, due to its purpose, has been notorious for security issues that allow malicious code to run outside of the environment of a web browser. Adobe has maintained the software to fix many of these issues as they are discovered, but has decided that it's no longer worth spending effort into keeping up with known issues.",
"Software needs to be revised as operating systems and hardware changes, and more importantly to address security vulnerabilities.",
"Well, it doesn't *have* to be actively supported, but if it isn't then bugs aren't getting fixed (this is especially important for anything internet related like a browser plugin), and it won't be updated to run on newer systems.",
"Technology constantly changes and as new thing come out the older stuff that already exists often has to be changed or adjusted to be compatible with new technologies. So yes, if a software is intended to have longevity it has to be supported so that it can be changed to be compatible with newer stuff as it comes along. (This is a really really basic explaination, I'm sure somebody around here is capable of explaining better.)"
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ex07l8 | How are carabiners so strong? | Technology | explainlikeimfive | {
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"text": [
"Firstly you have tensile strength which is the force you have to apply to pull something apart. Carabiniers are made with steel and aluminum both of which are very strong metals. The second aspect is the shape they are designed to put all the force along the spine (side that doesn’t open) which is stronger than the gated side. So they are made out of stuff that is hard to pull apart and they are designed to put all the force on the strongest part of the device."
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ex1nbi | How exactly do Amazon S3/Hadoop/etc work? | How do they work and what makes them special? | Technology | explainlikeimfive | {
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"Note that I don't work with these technologies often, so this is my understanding of them as a summarization of the information available. (I've used Hadoop in the past, but a few years back) Amazon S3 is considered \"object\" storage. An object is a file and information about the file (metadata) that is stored in a bucket (container) along with a unique ID. The ID is used to access the information from anywhere that can access the Internet. This data can also be replicated across multiple geographic regions to make the retrieval faster, no matter where in the world it is accessed. It also scales (grows and shrinks) the amount of data that you are allocating (paying for) based upon what you put in it. In contrast, if you buy a hard drive, you can't just pay for 10% of it, even if you only use 10%. With S3 (and similar technologies), you just pay for what you use. In addition, if you suddenly need more space, you'd normally have to run out and buy more hard drives. With S3 it automatically expands to conform to your needs (within any preset limits you impose) Hadoop is a distributed processing architecture (really a group of different programs that work together) that basically splits operations on large amounts of data across different computers for performance purposes. One of the main tasks the Hadoop architecture can perform is called MapReduce, which takes the data and first performs operations on the larger sets of data, like filtering or sorting, and then reduces the data by operations like averaging or counting before sending it on to the next task. It is mainly used for offline (not real time) processing on what is currently considered very large datasets which would be exceptionally long-running tasks if executed on a single computer."
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ex23pt | Why is Microsoft's Windows allowed to have their Apps preinstalled and bundled (with bing search and Edge browser) while Google was fined for the same thing in Android by the EU in 2018? | Technology | explainlikeimfive | {
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"Microsoft creates N and KN versions of Windows which are stripped of their first party apps to comply with EU and South Korea regulation, respectively.",
"You might not be aware that in the US and Europe, Microsoft was in trouble for the same thing. Microsoft had bundled Microsoft Internet Explorer with Windows to the detriment of other browsers, resulting in a near monopoly for Internet Explorer -- something hard to imagine now that Chrome is dominant. But also keep in mind, it isn't *necessarily* illegal to bundle services and apps. Whether you have a monopoly, and whether you're abusing that monopoly, and whether your actions constitute predatory dealing (among other things) are nuances of law and seldom clear cut. Part of the case against Google is that they were giving away Android to suppress operating system competitors while then *also* abusing that monopoly to push Google products. To EU regulators, that went over the line, but if Google had stronger competition in the mobile space, it may not have.",
"Microsoft was fined and they made a website to offer users an alternative browser: [ URL_0 ]( URL_0 )",
"Microsoft got in trouble for having Internet Explorer and Windows Media Player pre-installed too. They were fined and had to include a browser choice window in their installer. Honestly your question should have been why Google and Microsoft got fined while Apple is doing the same things but didn't get fined. Or why this is apparently an issue on desktop computers and laptops but not on smartphones, which come pre-installed with a load of software...",
"As far as I know, bing isn't actually installed and you have to have some browser to download your browser of choice. If I had to guess, it's that Google had truly unnecessary things installed that couldn't be readily uninstalled. Windows is right on the line with Cortana and other things, but hasn't crossed over it yet.",
"Here's some more food for thought. When you buy windows, even if you have the us version, you. An always uninstall the apps. All you want. Nothing will stop you. On android, when google, verizon, sprint, tmobile, apple and others put pre installed software on your phone they do it as a system app, and you cannot remove them. You may disable them, but they are still there. So if anything they all need to be fined for selling OS with malware...",
"Because you can uninstall them? I can't uninstall Gmail or Chrome on my phone. I have no idea. Just guessing.",
"[Microsoft has lost a case on this before]( URL_0 ), read it if you have a free afternoon and youll understand the way the ECJ deals with this.",
"Can someone answer them why Apple doesn’t get Charged for the same thing as well?",
"Micorsoft was fined too ( [ URL_0 ]( URL_0 ) ). I think they got around it in future versions by allowing and promoting other browsers, but don't quote me on that.",
"The better question is why are Microsoft allowed to bundle adverts for candy crush into their start menu when the OS costs £200 in some cases? Especially when their main competitor's OS is free and ad-free",
"Why does Apple get away with the same thing? Even Microsoft lets you change your default browser but Apple sticks you with Safari when you open a link outside the app. Apple is by far the worse at this than Google and Microsoft ever were.",
"Why is Google allowed to bundle Chrome on Android if Microsoft got in trouble for doing it with IE on Windows back in the 90s?",
"It’s the license. Other companies make the hardware, but Google (and M$) require companies that sell their software to do certain things. Google only makes a few phones and computers and Microsoft doesn’t make a computer (unless you count the Surface or the X-Box lines). Apple doesn’t fall into this because they sell their own hardware. There are no rules they’re enforcing on another company.",
"Why is apple allowed to bundle their apps into MacOS? They don't make N versions?",
"The bigger question is how does Apple get away with actually bundling EVERYTHING. They are just as big as Microsoft but don't have to follow any of the same rules. Microsoft has been forced to dumb down everything. There's a reason media player looks like it hasn't been updated since 1998 and Microsoft didn't switch to the zune software as their default software despite it's sexiness.",
"Microsoft is also about to push out an office update that will FORCE the bing search engine to be your default in chrome. Really not sure how they are gonna get away with that move after their antitrust history. Now I have to make preventative changes for clients so they don't flip out because Bing is a completely useless search engine, and this will confuse them. & #x200B; [ URL_0 ]( URL_0 )",
"Question: why is Android, an open source project, offered for free to anyone who wants it (specifically AOSP) not allowed to make a stipulation that says \"if you want to OPTIONALLY use Google play, a service by Google, owned by Google, made entirely and hosted entirely by Google on an operating system that is offered for free, you must include our other apps\". That seems like the opposite of a bad thing to do. They allow anyone and everyone to use Android, but if you want to reap the value of their service that they maintain, you must help them by building their market share Is that not the same as saying \"you are allowed to live in my house for free, but if you want to eat my food and use my internet you have to pay rent\"? I truthfully don't understand how the EU thinks they are abusing market dominance because they force vendors to submit to their software package IF AND ONLY IF they choose to use the Google play store.",
"If you have no browser to start with how can you download Chrome?",
"Why is this even an issue? Internet explorer works great for downloading Chrome or Firefox."
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ex523w | Why do laser mounts of guns exist? | I understand that it makes you more accurate because it shows a dot where you are shooting. But dont they give away location and enemies know where you are shooting, thus they can flank you? | Technology | explainlikeimfive | {
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"The lasers in movies where there is a long green line in front of the gun aren’t real. Or, at least aren’t normal. Maybe that’s what it looks like if you’re wearing night vision goggles or something. The “laser scopes” I’ve seen for hunting, you don’t see anything except the dot that is on the intended target.",
"If you are engaging with an enemy that is organized enough to use small unit tactics under fire like flanking, then they’ll figure out your location as soon as you begin firing, lasers or no. The situation you are envisioning (close ranges, unaware but professional enemy) is very common in movies and video games and very rare in real life engagements. If you are on a dismounted patrol with skilled adversaries in the area, they already know where you are. You’re patrolling a market or city street and are very conspicuous. If you are sneaking up on a professional force, guarding a building or perimeter, then you are only covert at a distance. Once one of you makes contact, especially if that is with small arms fire, then your position is blown. Amateurs might have trouble figuring out where incoming fire is coming from, but amateurs aren’t likely to flank you. They are more likely to panic or return fire without much consideration for tactics.",
"Generally speaking laser mounts are only used in very short range engagements. The beam of the laser isn't usually visible, instead it is only the projected dot which is visible to the shooter (and it does provide a bright light from their position as well). A sniper for example wouldn't want to use this because it would give away their position, be only vaguely visible from their range, and wouldn't be pointed in the right direction anyway (being aligned with the barrel rather than the scope). That sort of thing is just for the movies where they need to show a gun is being pointed at a character without actually showing a view down the scope. Instead lasers are used when relatively short range encounters are expected. Pointing a firearm at a target very quickly while under duress is actually somewhat difficult, especially when it is a pistol where there are tiny sights on the top to align. By using a laser sight pointing the firearm is basically as simple as directing a laser pointer: Put the dot on the target and the barrel is pointed in the right direction as well. Bullet drop isn't relevant over such short distances so that is sufficient to indicate where the shots should strike."
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ex58gf | How a USB hub works? How can 1 USB carry the bandwidth of 5 or more? Wouldnt it be split? | Technology | explainlikeimfive | {
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"It is split, but most usb devices don't actually have high enough bandwidth for that to matter. Devices like mice and keyboards and stuff like that barely need any bandwidth at all. USB 2.0 has a max bandwidth of 480 Mbit/s which is enough for almost anything that used it many times over. Modern USB 3 /USB-C can have between 5 and 20 Gbit/s depending on the version and future versions of USB will have more. This is more than enough to handle any I/O a regular computer might want. The bandwidth isn't shared equally between all devices, so a mouse or keyboard will not take the same share of the total bandwidth as an SSD or an Ethernet connection via USB. One limitation is that a single controller can only talk to up to 127 devices and is you are daisy chaining usb hubs a lot of that will be taken up by the hubs themselves as there may be several hubs hidden within one physical casing. (For example a 7-port usb hub is usually just two 4 port hubs plugged into another in a single case and counts as two device by itself.) Another limitation is the fact that the host computer will talk to each device one at a time and can't be permanently talking back and forth with all devices, but that isn't really an issue for most use cases."
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ex7s60 | In a law and order episode, they confiscated a guys computer but he had strong electromagnets in the door frame that wiped his HD when they walked out of the room with it. Is something like this even possible or is it just on TV? | Technology | explainlikeimfive | {
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"In principle yes, a strong oscillating magnetic field could scramble the bits in a hard drive. However magnetic field strength drops off sharply with distance so in a practical sense trying to wipe everything going through a doorway would require an absolute monster of an electromagnet. People are likely to wonder why your doorway looks like an MRI machine."
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ex9ino | Why are downloads from some places faster than others? | For example, when you download a 5 gigabyte game on steam, it’s usually faster than a 5 gigabyte file from chrome. Why is this? | Technology | explainlikeimfive | {
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"There are two considerations: 1) where you are downloading from 2) how you are downloading For example there are free file sharing sites that limit your download speed, so this is on them. They are limiting you. If steam servers aren't overloaded, they will give you as much as speed they can. The second one is a bit more technical, it's comes down to download accelerators. Like what IDM does. They kinda take your bandwidth hostage and squeeze as much speed they can. Chrome however doesn't do this (?) And so they don't squeeze your network shut.",
"The main reason: The service supporting the download has a far better distribution setup. So for a company like Steam (whose main service is providing downloadable content), they need to have their infrastructure primed for delivering that content. - That means way more servers dedicated to downloads. - Wider server distribution globally so users don't have to access a server across the country. - Streamlined algorithms and server setups to account for peak download times, user load, game popularity etc."
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ex9otr | Why haven’t we made an airplane that runs on solar power | Technology | explainlikeimfive | {
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"They did. It flew around the world. It isn't practical, though, because sunlight only gives you on kilowatt per square meter of surface area, and solar panels can only use a fraction of that, so less than one horsepower for a square meter of solar panels. That is barely enough power to keep the fragile one-person plane they built aloft. Forget carrying passengers or cargo. That one kilowatt per square meter is a hard limit: no amount of technology can make the sun shine brighter! URL_0",
"Putting enough solar panels on a plane to get the energy to run it would make the plane so heavy that it wouldn't be able to fly. We don't have the technology yet to make solar panels powerful enough and light enough for them to be useful to run cars or planes.",
"The amount of energy that can be generated per second from the amount of solar panels that can fit on top of a plane is not enough to run the plane. There are other concerns, like making solar panels tough enough to withstand takeoff and landing and high speeds, but the whole \"there isn't enough energy in that much sunlight\" makes all the other concerns meaningless",
"There are prototypes that work but planes simply need to much energy to fly using only (current) solsr panel technology"
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ex9swy | How does technology remember or know what time it is even after being completely shut off? | Technology | explainlikeimfive | {
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"Many electronic devices have a small button battery, which runs a chip that keeps time while there's no power. These batteries will last for years, usually longer than the actual device itself, so most of the time they never need to be replaced. Smaller devices like phones don't have this though, so they'll sync with the internet or cell towers whenever power is applied.",
"Technology does not remember or know what time it is even after being completely shut off. Technology that always needs to remember or know what time it is doesn't completely shut off but keeps a clock running off a small battery."
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exevxn | why is there a color effect when you press hard on a monitor screen? | Technology | explainlikeimfive | {
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"The L in LCD stands for \"liquid\" - there's a thin layer of liquid that responds to electric signals to affect how much light it lets through. The monitor uses this to display an image. When you press on the screen, you're squishing the liquid around and making it show all the wrong colors"
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exlraq | why are todays cctv images still kinda crappy? | Technology | explainlikeimfive | {
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"Because the goal isn’t to get a perfect image, the goal of cctv is to continuously surveil. It would take way too much space to properly store a consistent stream of super HD video, therefore the video quality stays crappy!",
"Cost and not technology is the main reason many CCTV is crappy. There exists amazing very high definition cameras for traffic that can read your license plate from very far away, after automatically determining broke rules. We don't have them everywhere because they are expensive."
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exnf4s | Why do content creators need 100% calibrated displays? Aren't consumers going to buy non-calibrated, over-saturated displays anyway? | Technology | explainlikeimfive | {
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"You are right that most consumer displays have poor color accuracy, though more devices are starting to come with calibrated displays. Professional content creators don't use calibrated displays so that you and I see things correctly, but rather to ensure that when working as a team every member sees the same thing. If they were to all use consumer displays then, for instance, you might have someone who's display has more of a green tint and might adjust colors to compensate, but then it would look wrong to the rest of the team and it would be a constant back-and-forth."
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expver | When you buy software, the source code usually is not made public, but doesn’t your computer still have to run the code to use the software? How can it run the code without allowing the user to see the code? | Technology | explainlikeimfive | {
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"Say you have some source code... in your source code is the line \"if playerhealth < 0, gameover = true.\" Seems pretty easy to understand. Now the compiler will convert that into binary. It will look something like this \"010111000101010010.\" You can decompile it, but the compiler through out all of the variable names and just gave them numbers, so now you're left with \"If AE0 < 0, 0F1=1\" Now maybe you can play around with the game and the code, and eventually you'll figure out that AE0 means playerhealth and 0F1 means gameover... but you'll have to do this with hundreds or thousands of variables. It would be a daunting task for any modern software, to say the least.",
"The computer doesn't run the software directly from the source code. At least not with most programming languages. With something like C++ the source code is \"compiled\". Which means it gets converted into machine code, which is what the computer can actually execute. This is a one way process. Lots of contextual information is thrown out, so it's impossible to convert it back into the source code. It's theoretically possible to convert it back into valid source code, but it wouldn't be the same as the actual original code and it would be very difficult to make sense of.",
"The source code is like a blueprint to make a car. The blueprint describes all that is needed for the factory to build the car, and the source code describes all the instructions for the *compiler* to build the software. The finished product, the software, doesn't need to know how to *make* said software, it just tells your computer how to *run* it - just as a car doesn't tell you how to run a factory to make the same car. A little more in depth: source code compiles into *assembly* code and it's this that your computer runs (essentially just a bunch of instructions on what to display on your screen for given inputs). Source code is written in a way that's easy for humans to understand and therefore big projects can be achieved in a relatively small amount of time - but the assembly code this compiles to is much more complicated and not so easily understood by your average programmer.",
"The code you run is computer-readable. It's incredibly optimised towards making things fast for the computer to do, not easy for a human to understand. The original source is the complete opposite. To get from the former to the latter is possibly one of the most difficult tasks in computer science, and even for the best programmers. Reverse-engineering published code is simple, right?! So we're all running Windows 7 reverse engineered back to run on a Mac, aren't we? No. It can take \\*decades\\* of effort to reverse-engineer mere years of work, and when you're talking about anything substantial, the man-years of work involved in the creation are enormous. We haven't properly reverse-engineered the Windows file-sharing components, not the Active Directory (i.e. logon server) components yet. Samba Project has been trying to do that for about 20 years now, and even received documentation (not source) from Microsoft to do it, under an EU court ruling that said they had to. It's more akin to un-scrambling an egg... uncooking it, unravelling it, reassembling it back into something that resembles the original egg. And worse: You're doing it blind. You have no idea what's code, what's data, where the boundary lies, what the code-paths are, what any of the instructions are trying to achieve, how they're doing it, what the original code looked like, or what anything was called. All you see is a bunch of millions of numbers modifying each other. The computer loves that, that's what it was built for. Humans have the worst time interpreting that. And you need to be an expert programmer, in both the language it was written in, the compiler that was used, and the machine language that it ended up with, to even \\*begin\\* to start on it. Even old 1MByte DOS games that sold millions of copies 20+ years ago haven't been reverse-engineered yet. The number of people skilled enough to able to do it, the number of those able to devote that amount of time to it, the number of those that will happily do it for free, the number of those that \\*want\\* to do it, and the number of such other things that - with those skills - they'd rather be doing: it all combines to make it a rare and unusual thing to even start. If a game took a team of people 5 years to write, assume it would take a similar team of people 10 years minimum to reverse-engineer. And then... what? You expect them to give the source away for free after 10 years of working 9-5 on it? And you expect not to get sued by whoever owns the rights to the game in the first place? Reverse-engineering software is, sadly, a true waste of an enormous talent that is better put to making new things. Even emulators and the like are incredibly difficult to write, and that's when you know everything the machine can do and can just follow books on how the chips operate. Reverse-engineering machine code back to usable code is really a dark art requiring incredible skill - which is why most people just run an emulator if they want an old game. It's easier to write an emulator that it is to reverse-engineer. And most programmers probably couldn't write a decent emulator.",
"The code is compiled into machine code, a language that your computer can read and understand. You could try to read the machine code and understand what it does - that's [reverse engineering]( URL_0 ) - but it is a difficult process. For example, the original source code contains a lot of data that is only useful for the programmers, such as comments and function and variable names, which are stripped when the code is compiled. Sometimes the code might even be [obfuscated]( URL_1 ) which adds another layer of complexity to the code. Besides, \"open source\" usually doesn't just mean that the code is available, it also means that the code is legally free to use (with or without certain limitations)."
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exs407 | Augmented Reality and the difference between it and Virtual Reality. | Technology | explainlikeimfive | {
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"VR = you see a fake scene, created by computer graphics. AR = you see the real world, plus some graphics.",
"Virtual Reality creates a computer simulated environment around you. Augmented Reality puts virtual aspects into your real environment."
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extzat | How was the first clock programmed? | I can understand the logic behind a mechanic clock, but I mean like in a computer. How was someone able to tell a computer how long a second was so that it could be constantly changing in an accurate way every second? | Technology | explainlikeimfive | {
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"pretty much everything these days uses a crystal oscillator, such as quartz, which you can manufacture at difference frequencies. these oscillators \"vibrate\" or modify an electrical field at a precise frequency which you can then use to generate clocks for digital circuits or keep track of time for watches. there are other types of oscillators which vibrate at different frequencies depending on what your use is.",
"> I can understand the logic behind a mechanic clock Then you understand the logic of a digital clock. Find something that oscillates regularly over time (such as the vibrations of a quartz crystal or the swinging of a pendulum). Create a machine/circuit that activates on each oscillation (such as a rod on the crystal that makes and breaks a circuit as the crystal vibrates, or an escapement that allows a gear to rotate only at the bottom of the pendulum's swing). Count the oscillations and send a pulse once one second's worth of them occur (the more regular and precise the oscillations are, the more accurate the clock will be). Create another machine/circuit that ticks up by 1 whenever it receives one of those pulses. You now have a clock."
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exv9f7 | A small-case 4-letter password has 456,976 possible combinations. Why is there a need for even stronger passwords? | Technology | explainlikeimfive | {
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"While ~457,000 sounds like just an absolutely unfathomably large number to a human, that's actually child's play when it comes to computers. [Kasperky Labs]( URL_2 ) estimates that an average computer that's not even particularly specialized to password cracking can attempt roughly 7100 passwords every second. That means it could figure out a 4-letter single-case password in at most 65 seconds. I'm sure you can see why that's not very desirable. Even just stepping up to a six-character password where lower case, upper case, and numbers (but no symbols) are allowed slows down an average computer's brute force attack to 3.5 days. This can be sped up by using known tables of common passwords that people use over and over again, or even just using a dictionary attack since most people use a password that's a word or some variant thereof (e.g. they might use \"acc1d3nt\" instead of \"accident,\" but a good dictionary attack can account for these variants too). And that's all to say nothing of the fact that people who make their living by cracking people's passwords are going to have specialized hardware that can crack passwords even faster. In 2012, [ArsTechnica]( URL_0 ) wrote an article about a then-new supercomputer that could guess up to 350 *billion* passwords every second (meaning the 6-character password from before could be cracked in a fraction of a second). And you can surely imagine that even more powerful hardware exists now, 8 years on. > Most websites also have a brute-force protection that disables password guessing after about 10 attempts. This is true, but again people who make their living cracking passwords have ways of circumventing this. Explaining the exact specifics would probably make this explanation not ELI-5 anymore, but the basic gist is that they don't actually crack your password by going to the website and entering each potential password one at a time. Else, as you mentioned, they'd get locked out and that would make the process take a long long time. Rather, what they usually do is they get their hands on a master password list directly from the source. This can sometimes come from a leaker who works for a particular company, but most often it comes from hackers breaking into to the company's database and getting the master list file that way. Now thankfully, any company worth their salt encrypts said password list, but that turns out not to really be a problem for hackers. Most of the time hackers know what encryption algorithm a particular website uses to secure their passwords (e.g. the ArsTechnica article mentions that LinkedIn uses the SHA-1 algorithm. Obviously, this may no longer be the case today, but it was true as of 2012). Given this information, they can use their brute force password generator and run each one through the encryption algorithm until they find one that outputs the same string as one of the passwords in the list - they then know that user's password. In addition to all of that, sometimes companies utterly fail at security and don't follow the industry best practices for securely storing passwords. In late 2013, a password list containing over 153 million Adobe Creative Cloud passwords was leaked. Subsequently, hackers discovered that Adobe did a very bad job securing this file. They used an encryption algorithm that is easily reversible and stored users' hints in the same file as their password. Properly secured password files also use a process known as salting, whereby if two (or more) users have the same passwords, they end up being stored as completely different encrypted strings... but Adobe didn't make use of this, so if the list showed, say, five instances of the same string, hackers just got a 5-for-1 deal on that password. As a final note, on rare occasions hackers will actually try logging in through the website and brute forcing it that way, if there's an exploit that circumvents the lock out routines. It's believed that such a vulnerability played a role in allowing the leaks of celebrities' nudes from their iCloud accounts back in 2014. [The Next Web]( URL_1 ) writes: > The vulnerability allegedly discovered in the Find My iPhone service appears to have let attackers use this method to guess passwords repeatedly without any sort of lockout or alert to the target.",
"Its important to remember that people don't pick passwords uniformly randomly - people normally pick words, and there are a little over 5000 4 letter english words, with some (like \"open\") far more likely to be picked as a password. Combine that with some basic tech that allows you to target more efficently (if I get 10 attempts per account then over a significant number of accounts I will probably score a hit) and you have a vunerability.",
"It is not as simple as you think. Yes they could implement brute force protection but there is an additional factor at play here. **Any service worth its salt will not store your password.** Password authentication systems use something known as a cryptographic hash to not store your password. A hash is a piece of data a couple dozen bytes long that is produced by a hashing algorithm. A hashing algorithm takes in any data and spits out this hash. Cryptographic hashing algorithms are designed to not be reversible, that is given a hash, it should not be possible to figure out some kind of data that hashes to it. It’s like a fingerprint (in fact hashes are commonly referred to as fingerprints). Given a random fingerprint, you wouldn’t know what person it belongs to. But if you know the person with the fingerprint, you can confirm it is theirs. So how does logging in look like from the services point of view? You send the service your username and password, the service hashes your password, looks in its database for the entry under your username and checks that the hash there matches the hash of the password you provided. If so, it knows you put in the right password and you are let in. Why not store the password? Protecting the business from itself. Database leaks are unfortunately fairly common. Computers are complicated, there will always be some bug or something that may let hackers into a master database. Check out URL_0 for some examples of these breaches in the news section. So the hackers will get a list of usernames and password hashes. They cannot use this to directly login to the account. They need to know the password, they only have the hash. Now this hash is a piece of data not a login prompt communicating with a server. The only limit on brute force speed at this point is how fast your computer is. Assuming some decent amount of complexity in your password, it will take decades to brute force it. We can try all combinations of 4 character passwords in less than a second if we have the hash. The longer and more complex the password is, the longer it takes to crack a hash. Complex password requirements are insurance against this, not against brute force logins. Additionally this scheme means that any service that sends you the password you set during any password recovery means that the service is not using proper security practices.",
"> That's a lot. For you maybe. Typing that many passwords in manually would take a long time. But not for a computer. It might be able to try hundreds per second, quickly breaking the password. It could even be much worse if some people are foolish enough to pick only real words of 4 letters in length.",
"Imagine the database got hacked and leaked. Now, any company that takes security as anything less than a joke would've hashed the passwords, so you'd have to try all possible passwords to find one whose hash matches that of some account. A modern laptop processor can perform several BILLION operations per second (accounting for parallelism). So... that won't take very long. And also, now the hacker knows a password you might be using in other places, too. This isn't uncommon, happens about once a month with some large company getting breached. Alternatively, let's say the website was NOT hacked. How long would it take a clickfarm with a few hundred workers randomly guessing passwords for random accounts to find one that works? On average, that's, let's say, 60 tries per hour, per employee. So 8x60x100=48000 tries per day for your clickfarm. You'll have breached into some accounts in no time. Not to mention, in some cases (e. g. Wi-Fi) your password can be used to encrypt communication. So let's say I listen to your wifi, and get the key establishment handshake. So now if I just knew your password, I'd be able to decrypt the packets. Soooo... I capture one packet, and start trying passwords until the resulting key decrypts the packet successfully. That won't take very long, either.",
"You only think about a direct web-based bruteforce cracking attempt. What if you get access to the password hash files? You download them, run a bruteforce cracker, and have the password in less than one second. Now think about the same happening, but every password takes several months to years.",
"I’m sure there is more to it than this but 500,000 possible combinations seems like a lot for a human to figure out, but with today’s technology a program designed to try all different combinations (sometimes referred to as “brute force”) would crack a 4-letter password in no time at all.",
"The problem is that hackers can steal the hashes and brute force them locally instead of just typing a password into the normal interface. It’s the interface that prevent people from making multiple attempts. But if you get the password database you don’t have to go through the interface. You get unlimited tries. And as complex as 4 random characters are, it’s no match for even a normal desktop computer. Even if you use symbols too.",
"Because computers are fast. Insanely, godawfully fast. You thought they were fast back in the 1980s, but now they're about a million times faster. No, I didn't say 'million' just because it's an arbitrary large number. They're *literally* a million times faster now. My PC is from 2014. Its CPU (AMD FX-6300) runs at 3.5GHz across six cores. In the time it takes a typical monitor to refresh *just one frame,* each core can process up to 58 million machine code instructions. If you wrote down one letter for each machine code instruction one core can process in one second, and it took you one second to write down a letter, you'd have to be writing letters since World War 1 ended in order to catch up by now. The PC sits about a meter away from my face while I'm using it; I literally can't watch the CPU run in real time, because even if I could see its inner workings operating at this distance, each core would have processed about 11 additional machine code instructions in the time it takes light to get from the CPU to my eyes. How does this apply to password cracking? Well, just now I tried hashing 4-character strings, using my own homebrew hashing algorithm, in Javascript, running in Firefox 72. (If you don't know what 'hashing' is, just understand that it's something a hacker would want to do to text in order to guess a password.) For 1 million strings, the script took about 1.3 seconds to finish hashing them all. For your 456976 strings, it took 0.77 seconds. That's single-core performance in Javascript. A real hacker would at the very least have a multithreaded C program running on all cores, gaining probably more than ten times faster performance than what I was getting; so a reasonable estimate for the time taken to guess a 4-character password on the CPU would be something like 77 milliseconds, enough time for a typical monitor to display about five frames. Very likely the hacker could take advantage of his GPU to run hash checks even faster. And very likely the hashing algorithm for the passwords is faster than the one I designed for myself. The math just doesn't work out. The 4-character password is *not even close* to long enough to resist bruteforcing attacks on a modern computer. What if you made the password longer? Well, if we assume that the 4-character case takes 77 milliseconds, here's how it breaks down for passwords of increasing length (all with just 26 alphabet letters): 5 letters: 2.5 seconds 6 letters: 1 minute 18 seconds 7 letters: 39 minutes 8 letters: 19 hours 9 letters: 24 days 10 letters: 1.9 years 11 letters: 54 years 12 letters: 1530 years Because of the way the combinatoric arithmetic works (you're multiplying the variety of passwords by 26 with each additional character), a longer password takes *far* longer to crack. So you are definitely much more secure with, say, a random 12-letter password than with a random 4-letter password.",
"Its not so much the length but that people use easy to guess passwords. Relevant XKCD. URL_0",
"From Steve Gibson’s Haystack Passwords site: URL_0 URL_1",
"Edward Snowden said small phrases are the hardest to crack that also have numbers, caps and symbols. His example was legendary: \"MargaretThatcheris110%sexy\"",
"Also: why do computers are allowed to try thousands of passwords a second? Why is it not mandatory a few seconds delay after a password try? (in websites, for example)",
"Human nature is to use sequences of numbers or dates for passwords, so there would be fewer combinations commonly used. With dates for example the first 2 digits might be months 01-12 and last 2 might be days 01-31.",
"Your average desktop computer could crack that with a simple brute force very quickly. Computers are very fast. Login limits obviously prevent brute forcing of websites, but should your hashed password ever leaked as often happens (i suggest signing up to [ URL_0 ]( URL_0 )) then it could be brute forced in minutes.",
"A single 1080ti graphics card can do about 50000 megahashes per second. So a 4 character lowercase alpha password would be cracked in no time. With the Advent of the cloud computing, even an 8 character lowercase alpha password is nothing. That's why its important to add as much entropy to your password as possible by using upper and lower case, numbers and special characters.",
"Half a million combinations may sound like alot to you, but for a computer that's nothing. Take a look at [ URL_0 ]( URL_0 ) to give you an idea. Examples: *password: iplaygames* **It would take a computer about 59 MINUTES to crack your password** & #x200B; *password: IPlayGames* **It would take a computer about 1 MONTH to crack your password** & #x200B; *password: I\\_Pl4yG4me$* **It would take a computer about 4 HUNDRED YEARS to crack your password** & #x200B; *password: I\\_Pl4yG4Me$4FuN* **It would take a computer about 16 BILLION YEARS to crack your password**",
"> a password of 4 letters would have 264 possible combinations But the company/website doesn't trust its users to pick a *random* collection of 4 letters. They want even their worst customers to be at least a little bit secure. > disables password guessing after about 10 attempts from a given IP If the company is hacked and the password information leaked, then while this wont directly reveal passwords (or it shouldn't, the company shouldn't know your password), people can guess passwords as many times as they like against the password information, and the nature of this information will let them know if they were correct. Therefore, if there are more possible combinations, then this protects your passwords from people brute forcing a hacked list quickly/easily.",
"Many answers already have the correct explanation for this question. The short version is that trying passwords in webpage is slow, and would take a long time. This is not how it's done. Instead, hackers can obtain the list of hashed passwords for a website. A hash is a method of converting a password into another string of characters that is practically impossible to reverse. The only way to discover a working password is to run it through the hashing algorithm and see if it matches the string of characters in the stolen file. This off-line method can happen very quickly for passwords under 12 or so characters, or for words in the dictionary, or for words with common replacements like p@ssw0rd for example. [Xkcd]( URL_0 ) has a relevant comic, as usual. Edward Snowden explains it well in this [video]( URL_1 )."
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exvqb8 | How does a compass actually work? | Technology | explainlikeimfive | {
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"text": [
"A compass uses balanced magnets on a pin. When you hold the compass upright, the magnet points north, but not geological north. It points to the magnetic pole. Fun fact, the magnetic south pole is actually in the northern hemisphere and the magnetic north pole is in the southern hemisphere. Since opposite magnets attract, the north pointed on your compass is a north magnet, and points to the magnetic South pole in the northern hemisphere"
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exw3cy | How do they remaster old movies to HD or 4k? | Technology | explainlikeimfive | {
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"text": [
"If you search for \"behind the scenes\" for 'They Shall Not Grow Old' the Peter Jackson film, you should find how they did the coloring. I seen something on how they color graded the old footage (along with added dialog via Lip Readers), but cant find the link right now."
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exwoyw | How does having increased FPS reduce input delay | Technology | explainlikeimfive | {
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"text": [
"The vast majority of programs are only able to scan for input on every frame. Having a higher fps doesn't necessarily decrease input delay, but rather gives you more input \"opportunities\" per second. If you have an fps of 5, for instance, the program will not register the input until the next frame has rolled around. As such it would take 1/5th of a second for your input to go through, and probably another frame for the corresponding action to take place."
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exxg8x | Where do spam emails get your email address from? | Technology | explainlikeimfive | {
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"text": [
"Places you've signed up can sell your email address to other marketers. Just like in the past places you'd given your address were able to sell your mailing address to marketers."
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exxvuw | How does a thermal camera detect the temperature of different things? | Technology | explainlikeimfive | {
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"Everything that is warm, emits light, in a spectrum that we can’t see. However we can definitely make cameras that can see it, and turn the light into wavelengths that we can see. All a thermal camera does, is look at light that we can’t see, and turn it into light we can see. Infrared exists on that spectrum.",
"A thermal camera is really a camera that records in the \"Far Infrared\" (FIR) part of the spectrum. Most of the radiation in that part of the spectrum comes from thermal radiation (aka black-body radiation). So you get a very dependable relation between the \"brightness\" of an object and its temperature. You don't really measure temperature though, rather some radiation that is highly correlated with it. It for example doesn't work well for metal objects since they reflect very well in that range of the spectrum. So they act like mirrors and you don't see the temperature of the metal object but rather the temperature of whatever is reflected in it. On the other hand most mirrors (in the visual range) are not good mirrors in the FIR range and when you try to take a mirror selfie with a thermal camera you only learn what temperature your mirror has."
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exzgda | Why do school computers run 3d modeling programs ultra smooth but my 1500$ gaming rig does not? | Technology | explainlikeimfive | {
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"text": [
"Check for any things you can do to optimize Inventor for your setup... or if you have stuff running in the background. Likely, your school's computer has set specific optimization settings, or decreased some other background stuff."
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ey0n0u | - When you charge your phone, the battery goes up to 100%. Why does it stop there? How does the phone tell the outlet to stop giving energy to the battery? Does the extra energy just loop through and go back into the wall? | Technology | explainlikeimfive | {
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"text": [
"There's a microchip in your phone called the charge management controller. It monitors the charge in your battery when you plug in. When it's full it switches to a \"trickle charge\" level, where it consume only just enough power to run the phone.",
"It stops there because the battery does not have any additional capacity. Phone charging circuits monitor the battery's capacity, charge level and battery temperature. If the battery is too hot or is full it won't call for any additional power. The extra power never leaves the wall if it's full. Edit: the power does leave the wall, it just goes towards powering the phone, not charging the battery.",
"The phone can control how much current it gets from a charger. Modern iPhones will actually charge quickly to 60-70% and then finish up charging only closer to the time you usually wake up. Anyway the fact that a phone can control this means it will stop receiving current when it’s at 100%."
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ey61j5 | is it possible for game Easter egg hunters to look at the games code to find all the Easter eggs? | Technology | explainlikeimfive | {
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"Generally, the code of a game is not available to players. The game is a compiled program rather than source code. The difference is sort of like giving someone an unassembled IKEA shelf vs a premade shelf from a furniture store. The sourcecode is like the IKEA shelf, where how everything works and goes together is right there in the instruction book. The compiled binary is like the premade shelf, where you know that it's a shelf, and what it does, but you can't really tell how it was made, what order the parts were assembled in, etc. If you really try, you can figure stuff out by looking at the premade shelf, but you need a lot of skill and a lot of time to get any real amount of information.",
"Yes and no. The thing here is the source code. You could imagine source code like a very big book. Written in this book is how you built everything in the game, and the game itself. So, it basically is a giant manual. But the game itself is not this manual. It is what was created by exactly following the manual. So if we imagine the manual describing how to build a coffee machine, the game would be this exact coffee machine. It is partially possible to get the information in the manual back from the product, but it is hard work. And as someone thought it up and only gave you the game, but not the code, it could also be permitted. There are some languages, mostly not used for games, where you built it yourself in time - so you get the actual code. But even with this you can still.imagine it like a giant manual. You'd read each and every chapter. And while you would be sure to fastly skip things you don't care for it does not mean that the Easter eggs are easy to find. Basically, you'd like a chapter or at least a header if we stick with our image. There is no guarantee there is this kind of structure representing the Easter eggs, or that they are called this way. They could just be in between all the other stuff (like they are in the game itself). On the other hand there are some games (flash games) that have an Easter egg when you look at the code, like a picture drawn by using letters or something. But in general, no. You usually don't even have the code and even if you do it's hard to navigate."
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ey6fow | What are developers changing when they optimize a video game? How do they make it run smoother? | Technology | explainlikeimfive | {
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"So, the thing about computers and programming computers is that you can solve the same problem half a million ways. However, not every way is equally good at solving the given problem. Imagine sorting a deck, for instance. Would you consider it better to * run trough the deck, forming four piles for the four suits, and then sorting each suit separately before combining to the final deck or * throwing the deck up in the air, picking the cards up at random, and seeing if they happen to be sorted, repeating if needed? When you optimize your game you're seeking for ways to make your game solve any of the thousands of tasks it runs every frame faster. This can be any number of methods, from simply changing a slow function to a faster function, to changing the underlying system, to better interacting with the hardware, to storing previous results so you don't have to spend time recalculating them when needed, or deciding where you can \"cheat\" by giving a less accurate but faster answer. Often it's just a few milliseconds here and there, but those tiny improvements add up quickly when you're doing that thing ten thousand times per second.",
"Imagine that there are two different people trying to give you instructions on how to perform some task. The first person is giving you instructions that are technically correct, but they are constantly running their mouth more than they need to, use fancy words that you have to look up, and have a very disorganized method of laying out what they want you to do. Then the second person gives you instructions that are very simple, laid out in a very methodical and deliberate way, and use Simple vocabulary you readily know. It is obviously easier to follow the second set of instructions. Basically, optimization is trying to figure out how to explain to a particular computer and set of hardware and operating system how to run the software in the most direct and simple way possible. It is trying to cut down on any confusion that would be caused by giving orders that are more complex than is necessary.",
"They usually run a [profiler]( URL_0 ) which analyzes various aspects of the program as it is running. It can be used to find which parts of the program take up the most resources, mainly time and memory. Once the most resource draining parts of the programs are located, the developers can move on to improve them. There are various ways of doing this, for example: 1. Time memory trade off - if the program keeps making the same calculations over and over, then it might be more efficient to calculate each of them once and store the result in memory. 2. Algorithms improvement - simply figure out a better algorithm to solve the problem. 3. Heuristics - sometimes you don't need to have a specific answer to every problem, so you can \"cut corners\" to get an answer that is good enough."
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ey8qyv | How do printers work? How do they know how to print different fonts, pictures etc. | Technology | explainlikeimfive | {
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"text": [
"The printer prints a grid of very small dots, perhaps of 4 colors if it's a color printer. Software inside the printer, including mathematical formulas that describe the shape of every letter in every font, converts information from your computer into the right pattern of dots. Then the dots are printed on a sheet of paper. That's what causes the pause between pages, the printer is \"thinking\" to calculate the dot pattern for the next page."
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eyb0le | How does a Wi-Fi extender work? Let's say if a certain location has a signal of -50dBm, how does adding an extender at that exact location boost the signal around it? | Technology | explainlikeimfive | {
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"text": [
"You add it before the signal drops, then it repeats the signal so it can be accessed further away.",
"The way I understand it is, the extender acts as a radio repeater. It receives the signal from the router or access point. From there, it re-transmits the signal on a different channel that is capable of being received further out.",
"It's like if you got your friends to stand in a line 50 metres apart A friend at one end can yell something loud enough for the second friend in the line to hear, they can then yell it to the next person in line",
"WiFi isn't one radio channel, it's several. The Extender listens on one channel, with a very sensitive receiver, and transmits on another, with a powerful transmitter. This makes the same network available on two radio channels. Since devices have algorithms to choose the most powerful signal, they will connect to the strong extender rather than the weak primary. For devices that are constrained in their radio antenna geometry, like a cell phone, this can be a big improvement."
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eybs40 | what exactly is cloud computing? | Technology | explainlikeimfive | {
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"text": [
"The cloud is just someone else's computer. When you're using a \"cloud\" solution, you are basically leaving the hardware management of those servers up to a team that does nothing but that, meaning you don't have to source out a server guy to do that if you're a smaller organization. Depending on what you're doing, getting a monthly subscription to a service like Amazon's S3 is less costly than buying and maintaining a server to do what you need, so it can free you up to do more coding or whatever it is that your business does. Public/Private/Hybrid cloud describe how exclusive your servers are. A private cloud is basically you paying for 1 hardware box that is not used by any other person/company; public cloud is like Amazon's S3 or Microsoft Azure where one server running VMWare might host a dozen or more instances of smaller servers running various services for different companies. Hybrid would be using some of both depending on what each individual cloud service needs."
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eyfha5 | What is the purpose of the "circular net" in front of microphones of recording studios? | Technology | explainlikeimfive | {
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"text": [
"Pop filter. Stops bilabial sounds like \"b\" or \"p\" from sounding like loud pops. If you've ever heard a low quality youtube video, you know the pop I mean. Basically it smooths out the audio.",
"It’s called a pop filter and is supposed to help soften certain consonants. When you sing you are typically louder than you are talking and certain things like s’s become more sibilant and p’s and b’s become more explosive (they’re called plosives after all). The filter is supposed to help regulate those sounds. Otherwise you may get a good volume on everything else but the words ending or starting with an s, b, p, whatever are ungodly loud and stick out against everything else.",
"Hold your hand in front of your face and make a 'p' and 'b' sound. You'll notice that a puff of air comes out when you make those sounds. As you might know, air blowing into a microphone is a no bueno, so these filters stop that air from reaching the microphone without entirely cutting out the frequencies that you want to hear.",
"A pop filter. Reduces plosives from getting into audio recordings(plosives are syllables such as p's and b's), whilst still allowing other sound to pass through.",
"When you say certain letters, like 's', or 'p', a puff of air comes out of your mouth. If you're talking to me from a normal distance, the puff of air dissipates before it can get near my eardrums. I only hear the vibrations that you create with your mouth and voice box. But if you speak directly into my ear, or into a microphone, the puff of air will hit my eardrum, or the membrane in the microphone which fulfills the same function. This puff is picked up as a (relatively) loud noise, which sounds similar to someone (briefly) blowing in your ear (because, well, that's basically what it is). One way to stop this from happening is to sit or stand further away from the microphone. But that's not a great solution because it also makes the recorded sound weaker. So a better way is to put this little filter between your mouth and the microphone. The filter lets vibrations through very well, but catches and dissipates these little puffs of air before they hit the microphone."
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eyg4i8 | How does the internet work? | Technology | explainlikeimfive | {
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"text": [
"Thousands, if not millions of computers all connected together sharing information is the most ELI5 way I can put it."
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eyh4z4 | why, in todays high tech age, do we still use film stock and lenses for movies and pictures, when it could all be done on a computer? | People spend tens of thousands on anamorphic lenses and such, when you could just film in 4K, add a lens flair filter, and crop it to desired ratio. Clearly im missing something | Technology | explainlikeimfive | {
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"text": [
"Despite the standard of digital sensors, film still has the advantage in some areas. You can massively over-expose film and still see some details, where digital will just give you solid whites. It's the other way around at the dark end. Some people still prefer film. But you talk about lenses too! Those are used for both film and digital sensors. I don't see an alternative unless you're proposing rendering everything with CGI. Good as computer rendering is today, it's still not on the level of real-world footage. More to the point, it's massively more expensive. Yes, I wish they'd dump anamorphic lenses for everything. Not only is all the flare and bokeh weird, but they breathe in such a strange way, with focus pulls causing the aspect ratio to change.",
"For the same reason professional musicians record onto tape; film and tape actually have practically infinite resolution, whereas converting recorded information into the digital realm is always limited by the current technology’s resolution capabilities, thus there’s is always something lost. Some might argue that what is lost in high end digital is imperceptible to the human senses, but others argue that there’s just a “certain something” that happens with film and tape that can’t be reproduced digitally for this very reason.",
"Lenses and film are two separate issues. I am no sure of the exact difference between the quality of capturing on film and digital and what advantages there are. But for expensive lenses, there is a huge difference If you capture an image with a regular lens and an anamorphic the bokeh is quite different. The bokeh is how out of focus stuff looks. An out of focus light on a regular lens is circular but on anamorphic the are oval. [Compare it here]( URL_1 ). There is no easy way to convert the captured images or videos between the two. You could create a completely CGI background with either but that is expensive so \"tens of thousands on anamorphic lens\" might the cheapest way to get the effect. So capturing real light in the camera just like you like it to be on screen with expensive equipment might be the cheapest option. For other stuff, your film with large lenses and you can get shallow depth of filed and another effect directly in the camera instead of expensive or complex post-processing. There is a reason cellphone try to add this in the portate modes for images with complex software. The different focal length of a camera has a huge effect on how stuff looks. [Look at this image]( URL_2 ) that how stuff gets distorted of flattened out at 16 to 200mm lenses and the amount of background captured and how the depth of field changes and take it out of focus. The framing and distortion is nothing you can change in a computer or at least not at a cost lower to capture it directly. The depth of field is simple but not something you prefect on a movie today with automatic software. So a lens might cost a lot of money but people that operate computers cost money too. Capturing the intention of the director directly in-camera will cost less at least regarding lenses. For a movie, tens of thousands are nothing when it cost tens millions, it is 1/1000 of the budget to make so get the right shoot directly will cost a lot less the for example & #x200B; Look at [This]( URL_0 ) for a breakdown of the cost for Annie (2014) with a total cost of $73 million where the, the production cost of $34 M and shoot 23 September 2013 - 13 December 2013 (according to IMDB). That is 11 weeks and 4 days. So 81 days if all are used or 59 if you work 5-day a week. The length of the recording days are long but let's use 8 and 12 hours For 59 day and 8 hours a day, it cots $ 72 000 per hour For 81 day and 12 hours per day, it cost $34 000 per hour. So regardless of you calculate it you get production cost of tens of thousands per hour so if the correct equipment can capture it directly or just a bit faster it will pay for itself.",
"Many people feel that using traditional filming methods makes the movies look better, as they prefer the way images appear when filming on film stock rather than going digital. Enough directors and cinematographers feel that way that a decent amount of films are done on film stock even today, despite it being more expensive."
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"https://parlaystudios.com/blog/feature-film-budget-breakdown/",
"https://www.bhphotovideo.com/explora/video/features/anamorphic-lenses-key-widescreen-cinematic-imagery",
"http://annawu.com/blog/wp-content/uploads/2011/08/focal-length-comparison.jpg"
],
[]
]
} | [
"url"
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| [
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eykqqw | how does an mAh work? How long will 1 mAh last on a smartphone? How long will 18000 last? | Technology | explainlikeimfive | {
"a_id": [
"fghsll4",
"fght7yv"
],
"text": [
"Batteries are rates in mAh, that's milliamp hours. If a battery can provide 100 mA for 3 hours it can produce 300 mAh of output. Smartphones are complex computers, with a bright display and 3-5 radios inside. The power consumption depends on many variables, so power consumption is always changing. 18000 is 18 times more minutes than 1000.",
"Completely depends on how much power the phone is using. A 1800 mAh battery can provide, on paper, 1.8 amps of power for 1 hour before being completely drained. Or it could provide 0.9 amps of power for 2 hours. How much power your phone uses can vary hugely. If it's in airplane mode with the wifi and screen off you phone will use almost no power and a 1800 battery could probably last 2-3 days. On the other hand if you are playing a cpu/gpu intensive game while heavily using wifi you could probably blow through that in 2-3 hours."
],
"score": [
21,
9
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|
eyktc3 | How does an atomic clock work? How does it start telling extremely precise time? | Technology | explainlikeimfive | {
"a_id": [
"fghsq6c",
"fgi3j6n",
"fgi0558"
],
"text": [
"An atomic uses a clump of atoms of a pure element. When excited, these atoms vibrate at a specific frequency that depends on the element's electron alignments. By counting the vibrations, you can get a very precise clock that's stable over a long time period.",
"Real atomic clocks use some gas of a specific element, like caesium or rubidium. The element has a natural resonance frequency, which means it interacts most strongly with microwaves of a specific frequency. You stick the gas in a box and beam microwaves at it. You can then detect how strongly the gas interacts with the microwaves (e.g. by producing more microwaves or absorbing them, depending on the design). So you have a circuit generate the microwaves at an adjustable frequency, and then you have another circuit basically \"tune\" the first one until it finds the best frequency, much like you would manually tune a radio to a station until you get the best reception. After a while the whole thing slowly becomes very stable when the right frequency is found and narrowed down. To count seconds, you have a third circuit just divide down the microwave signal. Since you know the frequency at which the gas should resonate, you just count up to that number and every time you reach it, a second has passed. The store-bought clocks you find labeled \"atomic clocks\" are just normal clocks with a radio receiver that picks up time signals sent by a radio station that itself has a real atomic clock.",
"OP - you are not asking about the \"atomic clocks\" that sit on a desktop or a nightstand, are you? If you are, those DO NOT have a cesium atom vibrating inside. Those clocks actually have radio receivers that listen for data transmission by NIST (in the U.S.). Those radio transmissions are linked to the NIST atomic clocks which DO have a cesium atom vibrating inside. Side note - I have 3 different desktop \"atomic clocks\", no two of which display the same time, and none of which displays the correct time. Admittedly, they are all quite old - 15-20 years."
],
"score": [
71,
49,
19
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eylgx9 | Why is the Dvorak keyboard layout faster to type on than QWERY? | Technology | explainlikeimfive | {
"a_id": [
"fghzphs",
"fghwhwy"
],
"text": [
"Bear in mind, the whole \"qwerty was to slow down typists\" is oversimplified way too much. It did make sure some combinations (th, st) were separate to prevent jams, but by engaging both hands, the layout does quite the respectable job. Dvorak came like 50 years later from a guy who deeply studied letter frequency and physiology, and was able to notice some really helpful patterns in English typing that make for a smoother process. But it's hard to unseat the default",
"Because QWERTY was specifically designed to slow typists down back when typewriters were new and jammed easily. It was meant to prevent such jams. Edit: source: URL_0"
],
"score": [
7,
5
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"text_urls": [
[],
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"https://www.smithsonianmag.com/arts-culture/fact-of-fiction-the-legend-of-the-qwerty-keyboard-49863249/"
]
]
} | [
"url"
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| [
"url"
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|
eylkeo | Why is it some North American plugs have 3 prongs while some have 2? | I am assuming it is due to requiring more electricity but I’ve had broken 3 prongs work with just 2 | Technology | explainlikeimfive | {
"a_id": [
"fghy5o3",
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"fgi2wf0"
],
"text": [
"Reddit won't show me the other 4 comments for some reason, so I may be just repeating the same thing as others, but it has nothing to do with how much electricity an appliance uses. It has more to do with the grounding requirements of said appliance. If there are exposed metal chassis parts that *may* become energized in the event of a short circuit, they will be grounded, which utilizes the third prong. The device will function without this safety ground, but if something inside shorts to ground, well, you're on your own.",
"When you plug in a three-pronged plug, that third prong is providing an alternate pathway for electricity in the event of a fault. If you cut the third prong off of a plug, you defeat the safety feature. Also, adapters were designed to use the cover screw to complete a ground circuit on some older plug designs.Aug 20, 2015 This was copied from master sparky",
"It's due to how the house was wired when built. Pre 1969, homes weren't required to be grounded the same way as they are nowadays. In wiring, you have 3 wires: hot, neutral, and ground. Pre 1969 building code allowed for just hot and neutral, which is the 2 flat prongs. After 1969, building code called for better grounding with electricity, so a 3rd ground wire was added for safety. If you go into a house built pre 1969, more than likely, if you check the receptacles you may see that the outlets are 3 prong, but the 3rd prong is improperly grounded as the house is wired with the old 2 wire system. This is a cause for concern as without proper grounding, it can lead to electronics burning out, breakers tripping after a power outage, and arcs across the outlet which can cause fires to name a few problems. Bad wiring as described is actually one of the top causes of house fires. I'm by no means an expert, so take what I say with a grain of salt."
],
"score": [
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16,
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eylw3w | how did we make the first computer operating system if we didn't have computers to make them on? | Technology | explainlikeimfive | {
"a_id": [
"fghzgay",
"fghyqyq",
"fgi06lg",
"fghzi68"
],
"text": [
"Computers do not require an operating system. An operating system allows for a lot of benefits, namely you can have multiple tasks run on the same computer. But there is no absolute need for an operating system, most early computers in fact ran without them, each person wanting to use one was allocated a time slot when their program could run, back when programs were programmed with punchcards.",
"The first computers took instructions via [punch cards]( URL_0 ). So you’d literally load a huge stack of cards into the system and it would read the code. Once it was in memory you could write that out to tape, and then subsequent machines would load the operating system from tape into memory.",
"The Operating System didn’t just suddenly appear out of nothing, there were many steps between the first computer and the modern operating system. The first computers did only one thing. The math people just connected wires and vacuum tubes to do the logical operations they wanted it to do. They weren't very complicated by modern standards, a human could do it by hand. If you wanted the computer to do something else, you had to rebuild the entire thing. Next they made it easier to do something different, by making it so you could just unplug and re plug the wires instead of building the whole thing. They also put together some bits that a lot of different math people were constantly doing, and just let you plug the wires into those. Next they made it so that rather than plugging in wires, the wires were all connected to switches you go flip on and off. Because that was easier. Next they made a machine that flipped those switches for you. They stored which switches to flip on punch cards and just put them into the machine. You can make the argument that this was the first operating system, though most people in the know would disagree with you. Then a bunch of people wanted to use the same computer with their pile of punch cards. So they started writing down when they could use their cards. They'd hand it off to somebody to load all their cards for them. Everyone then got sick of waiting for that guy, so they made a machine that figured out who gets to run their cards next and loaded the cards for them. This is probably where most people agree the operating system started.",
"Computers came before operating systems. The earliest ones simply ran programs that were physically wired into ROM by hand."
],
"score": [
9,
8,
7,
6
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"text_urls": [
[],
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"https://en.m.wikipedia.org/wiki/Punched_card"
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[],
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]
} | [
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| [
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|
|
eynxyo | What was the process of editing movies before the computers? For example, movies made in the early 1900s. | Technology | explainlikeimfive | {
"a_id": [
"fgi8kq7",
"fgi8jmy"
],
"text": [
"They had many film rolls which they would cut and splice scenes together. It made a mess and scenes that didn't make in the movie ended up \"on the cutting room floor\"",
"All sorts of clever techniques were used. One example is drawing on film. Like, literally hiring an artist to draw on the film once you've recorded stuff on it. Another example is cutting two strands of film and splicing them together - hence the term \"cut\". Yet another is projecting one or more existing images over a mask onto new film - this allows you to put multiple images on one screen. By using this creatively and with negatives you could basically make a greenscreen this way."
],
"score": [
12,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
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| [
"url"
]
|
|
eyodrp | What does equalizing audio do and what difference would enabling it make in the sound? | Technology | explainlikeimfive | {
"a_id": [
"fgib8bb"
],
"text": [
"When you are playing some audio the performance of your amplifier, speakers and the room is different for different frequencies. You may even personally perceive different frequencies at different levels making your individual listening experience different from everyone else. To correct for this it is common to use an equalizer which will split the sound up into different frequency ranges and allow you to select a different volume for each frequency range. So you are able to equalize the frequencies."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
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| [
"url"
]
|
|
eyq9j5 | Why is High Dynamic Range video exclusive to 4K resolution and up? | Technology | explainlikeimfive | {
"a_id": [
"fgin2th"
],
"text": [
"HDR 10 (the most popular one) video was a new format, it uses 10 bit video and the HDR channel. The timing made it right to attach it to the other new video standard of 4k. Nothing special means it has to be that way, but the timing worked out to just go \"you know what, just bundle all this stuff together\". Like you could have 8 bit video with hdr that is also 720p, but like, why? If you are changing one thing might as well change everything then."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
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| [
"url"
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|
|
eysb22 | How do password managers complete website forms in a manner that other browser apps can't capture the input? | Technology | explainlikeimfive | {
"a_id": [
"fgj5knd",
"fgiyfch"
],
"text": [
"They don't. When you or your password manager type in a password, any application that has access to your browser can see it. Any plugin you use has the potential to steal any password you enter. In practice, such an attack would be pretty obvious, anti-malware programs sniff them out pretty quickly. But in terms of managing your own security, passwords only really protect people from accessing your stuff from somewhere else.",
"Why do you think they can do this? The purpose of password managers is to enable strong, unique passwords. These passwords protect you from outsiders that don't have access to your computer/browser. If you're running some malware plugin then there isn't much they can do to help you. They can make the malware work harder, but nothing is perfect. What they protect you from is users that don't like complex passwords and just use \"Password/123\" on every site, enabling any random hacker in the world to cause mischief on your behalf."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
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| [
"url"
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|
|
eyst1p | Why AMOLED whites look yellow-ish compared to LCD whites? | I noticed that all AMOLED displays show whites with a yellow/red tint on them and don't look as "white" as LCD whites. Why? | Technology | explainlikeimfive | {
"a_id": [
"fgj9k2p"
],
"text": [
"Blue AMOLED subpixels burn out the fastest. Red and green subpixels create yellow, so an AMOLED screen will shift yellow as it gets older. LCDs don't burn so they don't change much over their life."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
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|
eyvte3 | How are deepfake voices created by using limited audio of the subject taking? | Deepfake voices, when audio can be manipulated to sounds like virtually anyone, is done using clips of the subject talking to my knowledge. How can just a few samples be used to project anything that can be said? | Technology | explainlikeimfive | {
"a_id": [
"fgjzjs0"
],
"text": [
"A billion monkeys with a billion typewriters. Deep fakes are made by having one program create a fake and another program test to see if it is a good fake. Because there is nothing manual in the process they can go through billions of attempts over time until they get a good result. Better programming and more source material will let them do it faster, but the basic idea remains. You don't write a program that produces a good fake, you churn out tons of fakes and take the best one."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
]
|
eyx3o1 | How were prescription glasses made accurately before the invention of modern technology? | Technology | explainlikeimfive | {
"a_id": [
"fgjskvk",
"fgjtmvr"
],
"text": [
"What modern technology do you envision? Spherical lenses were entirely within the abilities of technology 500 years ago. Prior to that we didn't really bother with glasses. Also prescriptions sure didn't exist. Such glasses were fairly limited to the wealthy.",
"We've been able to make relatively clear optical grade glass for a few hundred years (1400s I think). And the big/shrink factor of various curvatures has been well known and proven mathmatically for hundreds of years if not longer - the ancient greeks were describing the math around refraction of liquid in spheres. So if you know the math of refraction and calculate some some sample rays of light you can easily make a test pattern that appears distorted without a correctly ground lens but appears undistorted with a correct lens. From there its a simple matter of grinding and polishing until the test pattern looks correct. And they didn't make lenses to order. Spectacle makers would make a bunch of lenses of perscription 10, 10.5, 11, 11.5 and so on. If your actual perscription fell in between one of these standard focal powers the optician would round up or down to the nearest. Thats essentially what your Optometrist is doing with that funky facemask thing called a photoroptor when he asks you \"Which is better, A...? or B? Here's B... and here's A\" - its a systemmatic way of rough and then fine stepping through differnt powered lenses until close enough you can't distinguish between them. In the olden days theyd' literally have a box of little lenses and they'd hold them up in front of your eyes and ask you to watch the test chart."
],
"score": [
6,
4
],
"text_urls": [
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} | [
"url"
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| [
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|
|
eyytfz | How do the coils on a glasstop stove get so hot so quickly. | I noticed that as soon as I turn on a glasstop stove the coils heat up the area almost instantly. How does it get so hot so quickly? How is the energy source (electricity I'm guessing?) get converted into heat? | Technology | explainlikeimfive | {
"a_id": [
"fgk51bl"
],
"text": [
"Short version: It’s just really good at being really bad at conducting electricity. Heat from electricity comes from resistance to allowing the electrons from flowing smoothly. So, the worse something is as a conductor of electricity, the faster it heats up. Because the electrons all want to get from A to B really fast, and if they hit something (like an impurity in the conductive substance its traveling through just as an example) that energy has to go somewhere, and so it changes from electricity to heat. Kinda like the difference between a river that is deep and clear of obstructions and a river that has lots of boulders and whatnot in it. One of them is smooth like a logjam ride and the other is white water rapids splashing all over the place. Normally you want as little heat loss as possible because you want your device to run efficiently, But that’s not the case with the stove coil. You want a certain, but significant, amount of inefficiency so your coil will heat up quickly. They just used a good material that will provide the right balance of conductivity and resistance AND that will survive doing so. I hope that helps."
],
"score": [
11
],
"text_urls": [
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} | [
"url"
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| [
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|
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