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abe04x | Chromatic Aberration | I know that the term is used generally when it comes to photography. It has something to do with colors reaching the same focal point on a lens, anddd......I don't get it. I'm an artist, and someone I follow who makes comics has been using color fringing on purpose. Another viewer commented that it was a nice effect, but I couldn't see what they were talking about within the page, or how the hell they even spotted it. The examples I've seen are only super exaggerated images and show an increase in purple and green saturations. & #x200B; | Technology | explainlikeimfive | {
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"So, a lens bends light, right? Well, it turns out that not all wavelengths of light get bent the same amount. The red light gets bent a different amount from the blue light. Depending on the geometry and composition of the lens this will be more or less noticeable. But, it usually shows up as blue or red fringes around objects."
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abgdob | how are filed deleted on computers? Where does it go? | Technology | explainlikeimfive | {
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"When you delete a file, it’s not really “deleted.” It stays where it is. What happens is your computer declares the space used by that file as “available.” To actually “remove” the “deleted” file, you will need to overwrite that part of the disk. That can happen naturally or immediately by using an overwriting utility app like `shred`."
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abhjti | Why do Unicode emoji depend on the platform instead of the font which is used? | Why does their look depend on the platform used (as depicted [here]( URL_0 )) instead of the font? For example, if a certain font is used on character "A", its look does not depend on the platform on which you see it. | Technology | explainlikeimfive | {
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"As part of the Unicode set, emojis can be made part of a font. A complete font (with emojis and stuff) can be huge, so most systems probably store only one complete font and allow you to change only part of it.",
"You are correct in assuming it depends on the font, and not really the platform. There are two reasons why platforms have a typical style. First, there are tons of emoji and/or Unicode characters, and usually the platform provides one complete font (with all the characters) and lots of partial fonts (most about Latin characters, some about Asian ones). Second, programs decide to use either the selected font or their special font, then fall back on the system font for missing characters. Firefox on Windows have two styles of emoji, some are handled by Firefox emoji font, the others are handled by Windows, and some are not handled at all because Windows default font is not even complete. WhatsApp on Android also have its own emoji font (to be more uniform across all devices). Therefore the emoji on there are not the Android emojis."
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abj0jz | How are broken bones in non-castable areas fixed? | Technology | explainlikeimfive | {
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"Well, if you break the neck of the femur, they drill a hole and install a screw bracket through the femur and into the head of the femur to hold it in place while it fuses back together. You can't put weight on that leg for 6-8 weeks. Then you get to learn how to walk again, as the muscles have all atrophied. If all that sounds incredibly painful, it is.",
"Fingers for example are taped or splinted and taped. Personal experience more then once.",
"Many many ways. Depends on the fracture. The function of a cast is to stop movement of the bone while it heals. There are other ways to do this if a cast won’t work. For example: if the fracture isn’t that bad then the patient might be simply asked to not do ‘x’ movement for ‘x’ amount of time. Other examples: Slings can be used to minimize movement for collar bone fractures. External fixations which are like cages around the broken bones, can be used for more complicated fractures. Sometimes pins are put in place to keep a bone together while it heals and removed later like with certain finger fractures."
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ablhhu | How exactly does GPS work? | Technology | explainlikeimfive | {
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"It actually doesn't get your location. You only have a receiver. You don't send anything to GPS. It's like radio; you can only listen. Instead, you receive the coordinates of 3 satelites, and another one to get the correct time. From that, you can triangulate your location."
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ablopy | Console Exclusives | Why do developers make console exclusives? Wouldn't it make more sense to release to all platforms and go after a wider audience rather than create artificial scarcity (for lack of a better term)? | Technology | explainlikeimfive | {
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"Usually console exclusives are made as part of a deal with the console itself, with Sony, Nintendo, or Microsoft giving consideration (like Dev kits, commercial space, or money) in exchange for the full or limited exclusivity of the game. Sometimes, it's because of the differing architecture of the systems, with touchpad-heavy games on the Switch not easily portable to the PS4 or XB1. For PC exclusives, it's more simple. You don't have to pay for a Dev Kit to program a Windows game, and you don't have to pay for the right to launch the game, but you do with Consoles."
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abmohd | What advantages does the QWERTY key setup have over an alphabetical order setup that makes QWERTY the superior choice for North American keyboards? | Technology | explainlikeimfive | {
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"When the typewriter was invented, it used a metal bar to hold the character alphabets and the other end of the bar was attached to a linkage carrying a carriage with the coated ink. When a key was struck, it would emboss its character on the paper placed beneath the carriage. However, when an operator learned to type at a great speed, a certain flaw was noticed. When two letters were struck in quick succession, the bars of the typewriter would entangle and get jammed. Christopher Sholes found a way out. He proposed that the letters of frequently used letter pairs should be in different rows. For example, ‘C-H’, ‘S-T’, ’T-H’, ‘W-H’ and more. He also formulated that to speed up the typing process, there has to be a regular alternation between two hands. So observing thousands of words, he placed the letters in way that most words would make use of both hands. He also observed that almost every word in the dictionary carries a vowel. According to him, the most frequently used vowel was ‘A’ and the most frequently used letter (non-vowel) was ‘S’. So he placed ‘A’ and ‘S’ together and chose to keep less common letters like ‘Q’, ‘W’, ‘Z’, ‘X’, ‘C’ around these. This was complemented by placing fairly common letters like ‘M’, ‘N’, ‘L’, ‘K’, ‘O’, ‘P’ at right extremes to create a perfect alternation between both the hands. All these factors tested with thousands of trials gave us the format that we still use and perhaps would be using till eternity. Source: URL_0 And to your second question: There are lots of keyboard layouts for different languages, since qome languages have special characters (like ß from the german language) but most of them have the basic layout of either azerty or qwerty. There's also a dvorak layout which is arguably even better placement than azerty or qwerty. I prefer qwerty even though in my country (belgium) azerty is dominantly used."
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abnbmg | Why over the past 15 years, the typical CPU clock speed still remains around 2.8 to 3.2 GHz? | I know you can overclock the CPU to 5.0GHz, but I am not really talking about that. Desktop CPU clock speed has increased from 1mhz to 2.8ghz over the past 40 years. But has remained at 2.8 to 3.2 average over the past 15 years... Why not increase it along with other factors as well? What makes 3.0Ghz so perfect? And if the clock speed is not the bottleneck, why do people that overclock the CPU see improvements in performance? | Technology | explainlikeimfive | {
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"We're starting to run into some hard limitations of CPU manufacturing. The faster the clock speed, the more heat the chip will generate. If we push the clock speeds much higher than what they are today then people will need some exotic cooling solutions. The normal way to increase clock speed without creating more heat is to make the wires thinner which lets the chips use less voltage. But, we're getting very close to fundamental limitations about how small the wires can be. They use to be able to pack twice as many transistors in the same space every 24 months or so. That pace has significantly slowed in recent years. Finally, when you're talking about things happening in a billionth of a second, you start having problems keeping the entirety of the chip in sync. Electricity flows fast through the wires, but if we go much faster than the time it takes for the electrons to get from one side of the chip to the other will be slower than one clock cycle. This creates all sorts of new problems.",
"> What makes 3.0Ghz so perfect? It's not perfect, it's just hard to go past that. At those clockspeeds, you're getting to the point where fundamental limitations (like how long it takes light, which travels at 3 * 10^(8) m/s can travel across a cm wide chip) matter. When you were going slow, Mhz speed, it didn't really matter, it was easy to just go faster You also start running into other issues like cooling- the faster you go, the more heat you generate in a small area, that needs to be carried away. You also have to worry about keeping everything synchronized, and any potential lags/build up etc. Ideally, we would like to keep increasing clockspeeds, it's just difficult. In order to keep progressing, we've found clever ways around it (for now) like using multiple cores, or making pieces(transistors, particularly) smaller. But you can only make things so small. Here's some threads that go into more detail: URL_0 URL_1",
"They could push past 3.0 GHz and in effect, do, with unlocked chips that somewhat easily can hit 5.0 GHz or higher with moderate cooling. The problem is that it's kind of a relatively brute-force way of getting horsepower out of a CPU at this point because the power/cooling requirements are getting exponential and costly. There simply is not a economical, physical way to make it run faster besides just throwing more electricity/cooling at it. There are other ways to get more out of a processor and we haven't progressed as much there. The principle one is making a chip more robust and able to do more in one core cycle (Intel has been a pioneer in this scheme) but the biggest untapped gold-mine for speed gains is in physical multi-core processing and virtual multi-threading. Rather than make a core run faster it is cheaper now to just put another core in and make them work together, or to virtualize two cores so that a single core can accomplish more things at once in one cycle. Even though multi-core and hyperthreading have been around for a long time it is still kind of in infancy and has not progressed very well despite having large headroom to do so. The biggest reason for non-gains is probably the lack of motivation from software developers in taking advantage of it, because it is difficult to change or adapt their code. It takes so much effort and work that they will often just assume only 1 or 2 cores if they want to quickly turn a profitable product. This is evident pretty much everywhere outside large-scale data processing software. You would expect a game not being bottlenecked by anything else that is running 2 physical GPU's in SLI to gain potentially up to 100% performance but in reality often see maybe only 25%. Sometimes none, or even objectively worse performance. You see a lot of non-graphics software seemingly CPU-bottlenecked from the user perspective but then peer inside at the core usage only to find each one at a low % and not doing much. So the bleeding edge of progress as of late is the chip manufacturers and compiler authors figuring out how to abstract this burden away from the software developers and make it work internally/intrinsically. It has some of the most potential for speed gains while being an incredibly complex technology to advance because it takes fundamental re-thinking of how a system operates from the ground up, while software developers expect a cause-effect-cause-effect environment as they always have.",
"Generally power is the issue. Every watt consumed by the CPU becomes a watt of heat that you need to get rid of. Power consumption of a CPU scales linearly with the frequency so taking a 3 GHz 90 Watt chip and running it at 4 GHz will result in it using 120 W if you can keep the voltage the same Unfortunately higher clocks generally require higher voltages to get the transistors to switch fast enough and power consumption scales with the *square* of the voltage. If you have a chip that consumes 90 Watts when running at 3 GHz and 1.2V and then OC it to 4 GHz but have to step up the voltage to 1.35V then it'll actually consume 152 Watts not just the 120 Watts from above The voltage starts increasing quickly as you move to harder to achieve overclocks which causes the power consumption to rocket as well. Overclocking an i7-7700k to 7 GHz required over 2V, basically double the voltage, which would quadruple the power consumption",
"Actually the reason isn't heat or power consumption. Those are surmountable. The reason is that computers contain capacitors and capacitances, which is when parts of the transistor act like a capacitor. Capacitors, intended or otherwise, do a funny thing as the frequency of the voltage and thus current in the circuit increases. They start to act like wires. It's like taking all of the capacitors and capacitances out of the circuit and replacing them with wires. The circuit is no longer the circuit that was originally designed, and will not function as intended.",
"i see this thread has gone a bit too complex, Lets try to simplify this. A CPU is like a factory, Imagine it like a assembly line for cars but in reverse, there a command is taken apart to be executed in different parts of the CPU as if they were different stations of the factory dedicated to different tasks. Now through the entire factory there is a conveyor belt called a pipeline, This pipeline has 2 functions, its a linear distribution system which allows the analysis of each command and its disassembly so it can be distributed to the correct part of the factory for its execution. Now the frequency is not the actual speed of the processor but the pace in which that central conveyor belt moves, Frequency is usually 1/time. The other thing you have to understand is that the processor is made out of little switches, they are called logic gates which do simple math functions like addition, subtraction, division and multiplication using small electrical switches called gates using a type of math called Boolean, Boolean math is basically math applied to Binary code. Now depending on the instruction set you use for your CPU, Cisc, Risc, X86, Alpha... etc etc (Arm is a branch of Risc i believe) the CPU and the pipeline have a different method of taking apart instructions, and the CPU itself is designed to take big complex instructions and divide them in to smaller simpler tasks through the pipeline so they can be executed simply and efficiently. The pipeline can be longer which makes the instructions easier to take apart and analyze which is great with more complex tasks but slows down with simpler tasks the CPU due to handling less instructions per cycle or a shorter pipeline which will handle more instructions per cycle but might choke on more complex tasks due to not simplifying them sufficiently. Plus there is the issue of the logic gate density, they are little metal gates which are laser etched on a silicon waffle, Now the smaller the gates, the less power required to open and close them but when you pack too many gates together you can get electric migration which is a VERY simplified way means that the power used to move one gate can cause the gates around it to move as well, so every time you shrink the component size (usually defined by die size, in nM or uM, which is the wavelength of the laser used to etch the silicon waffle) you have to redesign the power delivery to the gates as well as improve the design structure as well as the etching system to better isolate the gates. Now going back to the assembly line metaphor, Frequency only tells you how fast the conveyor belt runs, it dosnt tell you how many assembly stations, how many workers or the complexity of the work done in each station, So judging the performance of a CPU using its frequency alone is like trying to guess how many cars a factory makes just by knowing how fast the conveyor belt in the factory moves, a CPU is much more complex and a CPU that runs at 4Ghz from one architecture can be slower then a CPU that runs at 1Ghz. A good example is graphics cards. A Nvidia 1080 TI in raw performance is faster then a top of the line i7 processor while running between one third and one half the frequency, but since they are designed for different tasks, one is making SUV´s and the other sports cars.",
"Now we have 8-16 cores in your average mid-top end build though. I'm no CS guru, but I'm guessing it's down to the engineering side.. only giving marginal gains with every new generation, due to the limits of manufacturing etc"
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abndl1 | How is data transferred from spacecrafts or satellites to Earth, particularly at such great distances? | With news of the New Horizons spacecraft bring millions of miles away from Earth, yet transmitting data and photos relatively quickly (with in tens of minutes), how does data travel from such a existence so quickly and reliably? How are we able to communicate with the equipment without the data being lost, losing signal, or compromising the quality of data? | Technology | explainlikeimfive | {
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"By radio, and then big receivers on the ground to listen, and send back messages. There's basically nothing between the spacecraft and earth, space is big huge empty place, so with proper receiving equipment, its fairly mundane to do radio communication from something, even insanely far out there in space, to back home on the ground here.",
"/u/WeDriftEternal gave a good answer. I just want to clear up a misconception in your original post. It takes about 6 hours for the radio waves from New Horizons to reach Earth."
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abt2uz | IS IOT(Internet of things) related to Computer science? | Technology | explainlikeimfive | {
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"Umm...kinda? Internet of things is the idea of connecting small devices to the internet that normally wouldn't have an internet connection. For example, smart light bulbs are an IoT device. All of these things require some programming which is in the domain of Computer Science. What are you trying to figure out, exactly?"
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abudzh | How much $ do bands get when we stream a song X number of times? When we have the option of downloading a song, like on Amazon Prime and playing offline, do they still know the # of plays when you go back online? | Technology | explainlikeimfive | {
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"You can find tables from various years the spell out what the streaming service pays per play out to each artist (with spotify it goes up when you have more plays - a way to placate the star performers who draw the most subscribers AND have the biggest legal budgets, but it was about $0.0039 per play last year, but it changes every month). How that is calculated for spotify is a pretty simple formula: Spotify's Monthly revenue x (total streams/artist's streams) = pay out. From the pay out, a percentage goes to the record publishers and an additional variable is added in to adjust up or down the pay out rate for an artist based on its total number of streams."
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abv6d4 | How does New Horizon send pictures back to Earth from 4 billion miles away? | Technology | explainlikeimfive | {
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"Radio waves. They travel at the speed of light. So from there, it takes a few hours to get back to us. There's nothing obstructing radio waves all the way back to Earth. It's a straight line (as opposed to terrestrial radio which is hampered by mountains and the curvature of the Earth). It's just not terribly strong, so we have to have big dish arrays to hear the signal."
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abvfac | Why do four-wheel drive trucks operate in rear-wheel drive instead of front-wheel drive when 4x4 is disengaged? | Technology | explainlikeimfive | {
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"The standard driveline setup for a common transfer case has the rear axle (back to wheels) as the main output because it's already inline. The front axle is usually engaged via a chain in somewhat of the same process as a gear on a bicycle. Once that happens engine power is delivered to the front and back until the chain is walked off. Again this is standard practice and I'm sure there are unique designs out there that operate differently",
"It's for traction. With 1000 lbs of rocks in your truck bed, the rear wheels have a lot more weight on them than the front wheels, same if you're towing anything. More weight = less slipping = driving up steeper hills.",
"To really simplify this for you, the engine and transmission point towards the rear of the vehicle, so because it is logical, and also in an effort to reduce power loss through additional components, it drives the rear axle first and foremost. There is a transfercase that it attached to the end of the transmission, and when engaged, it will allow power to be transferred to the front axle as well."
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abw9gc | How do scratches on DVDs screw up the playback? | Technology | explainlikeimfive | {
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"Data is read from the dvd using light. A scratch can mean that the light is reflected from the disc in a different way and meaning the receiver can not receive the data."
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abwdud | Why does a serrated knife work better to cut bread than a “flat/normal” bladed knife? | I know from experience it works better, just always wondered why. | Technology | explainlikeimfive | {
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"The teeth concentrate a lot of force on a tiny area, poking through the outer surface or getting between tiny protrusions. Once in, they cause a \"ripping\" action which gets the cut started.",
"The sawing from a serrated knife keeps it cutting through without pushing; other knives cause you to crush the bread. That said, a well-sharpened knife will work without pushing, too, and can give you a cleaner cut.",
"The pointed and curved areas of the serration have less contact area with the bread individually. There is also many of them along the length of the knife. This means it takes less pressure to cut into the bread so you dont mash it like you would have to do with a straight edge knife."
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abwl6g | How does my car know that I am tired? | I ask because our car recently gave a warning, when my wife had been driving for 5 minutes. My "you look tired" comment didn't land well. So my question is what metrics the car is monitoring to see if the driver is tired? | Technology | explainlikeimfive | {
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"It depends on the car but this is usually done by monitoring the steering angle, steering torque, and position in the lane as compared to baseline measurements. Basically she probably seemed to be weaving around and not making the steering inputs typical of an attentive driver. The \"you look tired\" comment not going over well means the \"a statistical analysis of your driving by a model rigorously developed by expert engineers thinks your driving is crap\" probably won't be good either.",
"If you are in front of the car you are tired. If you are behind the car you are exhausted.",
"It checks if your car is going outside of the lanes or ping ponging between them too often. On bad roads with poorly painted lines our car does the same."
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abwrzl | What causes a PSU that blows up to also sometimes take other PC parts with it? | Technology | explainlikeimfive | {
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"The PSU is the \"power supply unit\", so when it \"blows up\" you could have transient voltages making it to the motherboard, hard drives, etc. The job of the PSU is to convert 120 V or 220 V AC to the 5V and 12V DC that the computer parts use. When the PSU gets shorted or damaged, you could have 120V dumped into the 5V or 12V components, frying them too."
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aby3wq | Why did the burning of “The Library of Alexandria” set us back technologically? | I’ve seen here recently a few posts and comments stating that humanity was set back a few hundred years in terms of technology with the burning of The Library. It’s peaked my interest as to why? Why would the burning of an ancient library set us back so far in the future. | Technology | explainlikeimfive | {
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"It didn't set anyone back technologically. There were no secret weapons or forbidden knowledge hidden there. The value of the library was that it was a central hub of learning. There was so many rare and unique books there that it attracted a lot of really smart people. It may have been the largest library at one point, but it certainly wasn't the only one, and by the time it was destroyed, it had been in decline for quite some time. It's possible that there may have been some literature there that was unique. We'll never know. But in all likelihood copies of most of its collection probably survived (at least for a while) in the other libraries of the Mediterranean.",
"It wasn't really \"burned\" as such, it degraded over centuries. A lot of the scholars fled/left due to persecution of intellectuals, and while there was a fire (possibly an accident) it's likely this wasn't as bad as people often make it out to be. After that it faded away due to lack of funding.",
"Remember that at the time, books and scrolls were rare and difficult to make. The library at Alexandria was one of the--if not thr single--largest collection of these rare documents at the time. The burning of the library wiped out many documents that simply could not be replaced and did not exist elsewhere. Entire bodies of information could have been lost.",
"Knowledge was fragmented then, and the information lost wasn't accessible. Most human knowledge and inventions are based off of things we learned in the past - We don't have Reddit without the Internet, we don't have the Internet without Computers, we don't have Computers without resistors, etc. Say resistors were invented by someone who didn't share the knowledge widely - it was only in their personal effects at home - and their house was set on fire with arson (and that person was killed), someone else would need to re-invent resistors before someone could invent computers. Just the same, the knowledge lost in the Library of Alexandria wasn't replaceable - it all had to be replicated by someone else, and that information may have been more common knowledge had the library survived."
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abyii1 | What is RDS protocol and how does it apply to car radios that display a readout of the station/song/program? | Technology | explainlikeimfive | {
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"RDS - Radio Data System. It is a signal that is carried by station's transmission in what's called a \"subcarrier\". That subcarrier is outside the frequency range that the music is carried on. On the RDS signal, stations will often broadcast the title/artist for the current song and sometimes they'll transmit weather & traffic as well."
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abza5f | Why is sound for TV and movies barely audible for dialog and eat drum exploding for music and action? | Nowadays I can't watch TV or movies without the remote in my hand to raise and lower the volume between scenes. I eventually turned on subtitles full time so I could read dialog so the explosion in the next scene doesn't scare the neighbors. I'd assume during editing, someone watched their show or movie and decided this was okay? Is there some benefit that I'm not realizing? | Technology | explainlikeimfive | {
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"text": [
"[Dynamic Range.]( URL_0 ) The idea is that the sound is more \"realistic\" if it is louder when it should be loud, and soft when it should be soft. When an explosion is not much louder than a whisper, that is called [\"compressed\" ]( URL_0 _compression) audio. (This is not the same as digital compression, like mp3) We experience this in the real world, a freeway sounds louder than our living rooms, however, we usually have a transition period, or can anticipate the volume change. We cannot do this in a movie/TV show, so it is just painful and annoying, instead of enjoyable. This is one of the reasons I do not see movies in a theater anymore. It is impossible to be comfortable, when at any moment you can lose your hearing. Like you, I hate it. I *want* compressed audio. At some point, the pendulum will swing, and technology vendors will come out with some kind of \"advanced compression\" that is \"better\" than what we have now, and we will be shelling out $thousands for mid-80s audio gear.",
"It’s got something to do with the sound setup that they have in the cinema. So the sound is produced specifically for a 7.2 surround sound system, which most normal living rooms don’t have. On some sound systems, you can edit the EQ mode to equalise it a bit more. Reduce the bass, raise the volume over normal speaking range etc. You’d think that they’d change it for TV audiences, since the vast majority of people don’t have a home cinema. I’m sure someone with a background in sound production can explain it more thoroughly, but I hope that helps.",
"I hate that, it is so annoying.. when it is not explosions/gun shots, it is the music, out of nowhere my room became a concert! I also watch movies with the remote in my hand!"
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abzvse | How do candles work as an IR sensor bar for a Wii? | As the titles says, how do candles work as a substitute for the ir sensor bar for the Wii? I've heard that a TON of people says it works, but if it actually isn't bullshit, and it does work as substitute, how does it work, since technically TV remotes work on IR? | Technology | explainlikeimfive | {
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"Unlike what the name implies, the \"sensor bar\" isn't actually a sensor. It's just two IR sources spaced some distance apart. Any other pair of IR sources, such as a pair of flames could be used instead of the sensor bar. This is sort of the opposite of a TV remote. Instead of transmitting a IR signal, the Wii remotes actually look for a pair of IR sources, and determine where the remote is pointed off based upon where the IR sources are seen on the remote's sensor, the distance between the IR sources, and the calibration set earlier."
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abzzlk | How, with all sorts of radio waves and the like around us all the time, are we safe from negative effects from this? | Technology | explainlikeimfive | {
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"text": [
"Mostly because the waves have very low energy, too low to damage you. If I drop a facial tissue on your head it doesn't injure you, right? How about if I drop it, remove it, and drop it again? How about if I do it 1000 times? Doesn't matter — it's just too weak to hurt you."
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ac0c0c | How do developers of games and movies create directional audio so that you are able to tell if a sound is coming from in front of, or behind you when using a headset that just has a speaker in your left ear and a speaker in your right ear, and similarly with vertical sound? | Technology | explainlikeimfive | {
"a_id": [
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"I work in the field, specifically on these kinds of systems. Wall of text incoming. The most basic method is called panning. It usually as one knob controlling direction by altering the level of the signal in each channel. Something to the left will have a higher volume in the left speaker than the right, and vice versa. Something from in front of you will have the same volume in both speakers. This is because if a sound source is at an angle to your head the distance to one ear is shorter than to the other, and since sound decays with distance it will be louder in one year. Directly in front of you will have the same distance, so it will be the same volume. That difference in volume between each ear is called the interaural level difference (ILD) The next trick is to delay one channel from the other by a small amount. Again, since the distance to one ear is shorter the sound will get there earlier. The time difference between each ear is called the interaural time difference (ITD). Simple effects will do a little math to calculate what the ILD or ITD should be based on the source's angle and distance from the listener, with an approximation of the average distance between each ear (although everyone is different). The problem with that method is that ILD and ITD is not the same for all frequencies. There are two big reasons. The first is that your ear shape acts as a filter, meaning that it cuts or boosts frequencies. Think like an Instagram filter. The filtering done depends on the angle the sound wave hits your ears. The second reason has to do with the shape of your head. When the sound wave hits it, it bends around your head, causing delays between each ear. This effect is called diffraction, and it depends on frequency since lower frequencies have longer wavelengths than higher frequencies. One way to model that behavior is by pretending the head is spherical (or ellipsoidal) and doing some math to create an equation that models how a sound wave would hit it. This A better method uses something called an HRTF, or Head Related Transfer Function, and it's an equation that approximates how a sound wave behaves when it hits your head. These are measured by placing microphones in the ears of a user while they sit in a special chamber and recording sounds from different locations in the chamber. This has been done to a lot of test subjects, and you can create a decent average of an HRTF from that data. HRTFs work alright for some people, and the data is actually biased for certain ethnicities and head shapes so it's not perfect. These methods also only work on headphones, it fails with speakers. A bigger problem is how the sound sources in the game/movie are produced and stored. Your typical stereo recording only covers about a 180° sound field in front of a listener and doesn't help with things like distance or 3D audio. An alternative is called ambisonics, which uses more than 2 signal sources to capture 3D information about the sound source, and then the decoder uses things like panning and HRTFs to generate the stereo signal for the user. There are other 3D formats more commonly used in film and music, like surround sound and its derivatives like Dolby ATMOS and DTS. These use a thing called \"object based audio\" where in addition to the sound source you encode metadata like location (and some other stuff) with the audio, and a hardware decoder translates that in real time to render to your speaker system or headphones. Theres actually a new standard for how this works that will be pushed out to theaters in the next year or two. These work better on speaker systems, but they require you to have at least 9 speakers (and up to dozens) to actually play back in 3D. And positioned properly. There's a lot of work being down to get a good system to do it on traditional 2 channel speakers, like on a phone or laptop. A lot of them suck, but there are a handful with a lot of promise and they all do crazy shit that is secret or outside the scope of an ELI5 post."
],
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ac1oji | why do online or open world games tend to more “buggy” than other genres of games? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Cause you can't account for free will, who would have guessed johnny fuckbag was going to jump into the corner of this wall for a week until he finds a glitch. Also most devs don't pay for for an adequate amount of people to find bugs and prefer to just patch it after launch.",
"Because there's more they need to create. When there's more to create, there's more that can go wrong.",
"Short answer: there's more to go wrong. Longer answer: Having a game with online and open world elements both make it more complex and open up more opportunities for bugs. Having an online game requires the developer to deal with networking. Networking is unreliable in the best of circumstances. I once had an engineer tell me that 0.1% of all packets on the internet don't make it to their destination (on average). So, even if you make no mistakes in your networking code, you need to deal with an inherent unreliability. With networking you also have to deal with timing problems where things appear to happen at different times for two different players because there is delay in communication. What do you do if one player has a drastically slower connection than another player? What do you do if a player is intentionally feeding false data to your server? Dealing with these questions introduces more chances for bugs and just general weirdness. Open world games also introduce more possibility for bugs. Instead of being in a constrained environment where everything can be tested, your players can now go anywhere. The number of possible interactions jumps by an order of magnitude. It's going to be impossible to playtest every possible interaction and more bugs will slip in that won't get caught until release."
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ac1vl1 | How was the cartoon "SPLAT" sound effect made? | I've never heard anything in real life make that "ploik" sound that cartoons use for a "splat" sound effect, and I'm pretty sure the sound predates computers. So in that case, what physical object(s) is(were) used to make that sound? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"It depends on the splat. Food is used a lot for that in foley art. Canned dog food, jello, anything gushy, really, dropped from a height. Water or something more viscous can be added for layering or composite sounds.",
"Foley artists make and use some amazing devices to produce sound effects. Before computers [practical effects]( URL_0 ) were made and used to make sounds from slamming doors to crashing cars.",
"The stuff used to make a \"splat\" noise might not be a combination of things that would make that noise of it just fell naturally. Someone might actually be pushing their hand into a bowl of jelly over and over and that's just not something you normally do. Foley effects are pretty neat and there's no limits to the creativity that can be employed for it."
],
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"http://www.theatrecrafts.com/pages/home/topics/sound/sound-effects-for-the-stage/"
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ac23sw | How do these images work? | URL_0 I see these pictures a lot online and I don’t understand why the “hidden” image is only easily seen when shaking your head, and I also don’t understand how people make these pictures. | Technology | explainlikeimfive | {
"a_id": [
"ed4qrt0"
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"text": [
"I think it's to do with our perception of shape overriding our perception of color. Your brain locks in on the long black lines and ignores the color tinting of the lines as a distraction to be filtered out. As for creation, again just a guess, but it's some trick with layers and transparency. They put the cat picture in one layer dial up the transparency on it, then put the black bars over top, and the cat head only tints the black bars but not the white space, or something. Maybe a photoshop expert could explain it."
],
"score": [
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ac24os | How does NASA retrieve images from spacecrafts like New Horizons that are four billion miles away? | Technology | explainlikeimfive | {
"a_id": [
"ed4pcgh",
"ed4pbxs",
"ed4plb1"
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"text": [
"The spacecraft sends the picture via radio waves back to Earth. We receive the signal using large satellite dishes.",
"Light. It might take hours or days or longer to reach us, but it's still the fastest thing in the universe. It takes a powerful transmission beam and a very sensitive receiver, but it can be done. Edit: people down voting me may have forgotten that radio waves are simply a specific wavelength of light.",
"s l o w l y & #x200B; They use radio transmissions, but it takes a long time for even radio waves travel that far."
],
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ac2l8k | Why does more seeds = faster download speeds? | Technology | explainlikeimfive | {
"a_id": [
"ed4sofj",
"ed4snxf",
"ed4sy3o"
],
"text": [
"For many (most?) people, their internet connection tends to have faster download speeds than upload. There might also be limits on how much of a users connection can be used to upload content to avoid killing their connection for other uses and discouraging seeding. This means what they can provide individually is much less than what you can potentially take. The more of those relatively slow connections you get though, the closer their combined total is to your max download speed.",
"The total upload speed among all users is limited by the sum of the upload speeds of everyone who has a part of the torrent that people want. Thus, if there more copies of a file available and fewer people trying to obtain it, speeds will be nice for the user because there are few users competing for the available parts.",
"Let’s pretend your friend is literally distributing a DVD copy of a movie by hand. He burns a copy for each person who comes through his line. Everyone lines up to get this DVD. Now all those people have the option of copying that DVD to distribute to others (seeding) or just taking it for themselves (leeching). Now that so many people have copies of this DVD, it’s a lot easier for them to share it with more people. However with torrenting, bits and pieces of that DVD could be shared with you by different people, making the process even faster. It really just comes down to numbers...the more people seeding, the more connections to download from...therefore a faster process."
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ac336p | Challenges of having wireless electricity. | Technology | explainlikeimfive | {
"a_id": [
"ed4xnw8",
"ed4vrpg"
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"text": [
"Consider how the area of the surface of a sphere changes as the radius increases: A sphere with a radius of 1 meter has a surface area of 12.56 square meters. A sphere with a radius of 2 meters has a surface area of 50.27 square meters. A sphere with a radius of 3 meters has a surface area of 113.1 square meters. A sphere with a radius of 4 meters has a surface area of 201.06 square meters. The formula for the surface area of a sphere is 4(pi)r^2. This means that for every unit of increase in distance from the source of power you will be dramatically increasing the area across which that power is distributed (as it is being transmitted in every direction). Power directed in a way other than your desired devices is waste, meaning wireless transmission of electricity is *extremely* wasteful unless over very short distances or in a manner which is very directional. Short distances are of questionable utility as you might as well just have a direct connection so mainly they are used in situations where a sealed device is a benefit such as electric toothbrushes, or where convenience is desired as in cell phones. Directional transmission is difficult as it would require every transmission path be tuned and clear of obstructions or it won't work, or there be some sort of automated targeting system to perform such tuning. Static tuning negates much of the usefulness as you might as well just take the effort to run a wire in almost all cases, and automated targeting is both a technical hurdle and something people are leery of (do you want an automated microwave cannon installed in your ceiling and trust it will only shoot power at your cell phone instead of your face?).",
"Electricity takes the path of least resistance, so getting it to go exactly where you want it to go is important and that is why we use insulated cables, they give the current only one path to take. If you were trying to charge your phone wirelessly (without a special electromagnetic setup), the energy can redirect to other objects."
],
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|
ac3xmc | How can a projector project black onto something like a white wall? | Technology | explainlikeimfive | {
"a_id": [
"ed51eae"
],
"text": [
"It doesn't \"project\" black onto the wall, it simply projects nothing there and it relies on your perception. Black becomes relative to white in the image, as the projector is brighter than the room ideally."
],
"score": [
9
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|
ac6vvc | How is using a password manager different from using the same master password for every service? | Technology | explainlikeimfive | {
"a_id": [
"ed5mlvd",
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"text": [
"Password managers often store you actual passwords locally on your computer. Dashlane does for sure. So if someone gets your dashlane password it does them no good unless they also break into your house. Edit: also some crappily designed websites might not store you password for their service securily enough. If they get hacked the hackers now potentially have the password for *all* of your accounts. Using a Password manger they wont have a master password just the one for that specific account.",
"If you use the same password on 100 different websites, if any of them get hacked then they are all hacked. So, there are 100 different opportunities for a single service to have poor security practices. When you have a password manager there's only one place where getting hacked will leak all of your passwords. And, instead of it being some random website, it's a company whose main focus is computer security and they're more likely to pay attention to the details and not make mistakes.",
"If you use the same password for every service, and any of these services leaks your password, you are screwed. Using a password manager allow you to use a different, unique password for every service. This way if one of your password get stolen, only one of your account will be compromised. Now, if your password manager data get stolen, you are still screwed. However it is far less likely since password managers are typically a lot more secure than the average website and you only have one, not 200."
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ac7a0z | Why is this fossa gif so high quality | Technology | explainlikeimfive | {
"a_id": [
"ed5pue7",
"ed5pu49"
],
"text": [
"First, it's not technically a GIF. It's a video clip so it doesn't have the GIF format limitations. Second, the cat's hair makes it look higher quality than it actually is. It looks like there's a lot of details but it's just because the bits of hair on its face have high contrast.",
"Possible: 1. The image appears to have had some filters applied to it. One of the Imgur comments suggests it has been oversharpened so it appears extra crisp? 2. It took *forever* to load on my cell phone, so I assume it's a fairly large file. That means a lot of content, so possibly a very low compression factor?"
],
"score": [
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|
ac80c9 | How do hashing and password security work? | My user account was locked on one of my accounts at work. The agency unlocked the account remotely and, to make sure I didn't forget, they sent me my current password via email. Not a new password, my current one. I work at a bank and this is a credit reporting agency account. How do I explain to my boss that we should stop using this agency? This has to be a security risk. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"This is absolutely a security risk but it might not be one that they have a lot of control over. Best practice is to store passwords using one-way encryption. That is, you can encrypt something but you can't decrypt it. The result of this one-way encryption is called a hash. The hash of your password is stored and not the password itself. When you go to log in the password that you provide is hashed with the same process and then the two hashes are compared. If they match then they know that you have entered the correct password. That's how it's supposed to work. The fact that the agency was able to give you your current password means one of two things. First, it could mean that they use reversible encryption. This is bad because if the database of passwords was stolen and the decryption key was also stolen then everyone's password could be seen. The second, and much worse, possibility is that your password isn't encrypted at all. It's just stored as plain text. This would be really bad because hackers would only need to steal the password, not the key as well. But, sadly, there may not be much that the credit agency can do to fix it and other agencies might be just as bad. Banking was one of the first industries to computerize and they still have an alarming amount of code from 30, 40 or even 50 years ago running in their active environment. It's quite possible that those old systems simply don't support a proper one-way hash. Fixing that vulnerability could mean ripping out the very guts of their entire computer system. Then, there's no guarantee that another agency doesn't have the same problem.",
"I don't think you need to go into detail about how hashing works with your boss. Just tell him the possible repercussions of how they store passwords. For example, an employee of the credit reporting agency could potentially get your boss's password, then log in to the system as your boss, and do anything your boss can do. Also, depending on how big the bank is, see if you can get in touch with someone who deals with computer security and has some pull, and let them know. Might take some digging to find."
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ac8psa | How do you make clothes from plastic bottles? | Technology | explainlikeimfive | {
"a_id": [
"ed629t5"
],
"text": [
"Interestingly enough, and I just learned this, a large number of bottles (specifically soda, water, etc) are made out of the very same material as polyester clothing. Take a look at the bottom of your water bottle. It likely says “PET” or “PETE”. That stands for polyethylene terephthalate. Another name for this is “polyester”. When the plastic is made, is can be blow molded into a bottle, or drawn into super long and thin strands and woven into clothing (or other end use products). So it’s as simple (if you can call it simple) for the companies to take synthetic fiber clothes, separate out the polyester parts of it, carefully clean (and do some other more complicated separation processes) and the melt down the plastic. Then reform it into a bottle! Likewise, you do the reverse for turning bottles into clothes. Melt the bottle, clean, etc, draw into a fiber and weave!"
],
"score": [
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|
ac9efo | This image shows as an anime girl with a present, but changes to a gnome once I open it in a browser | Technology | explainlikeimfive | {
"a_id": [
"ed684ei"
],
"text": [
"If you visit URL_0 The app you use to view that picture will talk to the server at that address and request that file from it. However, when your browser makes the request, the server/website will also know what sort of browser and device you are using to access it. It will also know whether something sent you to the photo via a referral. You can intentionally configure it so that the file distributed at that address is different depending on the browser. It's the same trick websites use to prevent hotlinking, where an image is embedded in another website and gets blocked. (Ever seen the Photobucket hotlinking error?)"
],
"score": [
3
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"text_urls": [
[
"example.com/present.jpg"
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} | [
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|
acd1qw | How can gun sights indicate the bullet’s trajectory when it’s above the barrel? | Technology | explainlikeimfive | {
"a_id": [
"ed70oou"
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"text": [
"Gun sights have what is called a \"zero\". The zero is the range at which the bullet will hit where the sight is aimed. Closer than the zero a bullet will generally hit high, farther it will hit low. Most rifle and some pistols have adjustable sights that dial up and down so the user can adjust the zero to a preferred distance. Self-defense and combat-styled handguns usually have a zero preset at around 25m from the factory, with no adjustment (or adjustment that requires a gunsmith's tools). This is because they are intended for shooting at relatively close range, and usually use simple, easy to aim, sights that are not effective for long range shooting. In those cases simplicity is preferred over precision."
],
"score": [
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|
acdsqw | How can the new Chinese object left on the moon send information to earth if its always pointing away from earth? | Technology | explainlikeimfive | {
"a_id": [
"ed75jzz"
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"text": [
"They launched a relay satellite past the moon that's orbiting a point in space out there that can receive a signal from the dark side and then transmit it to earth once it gets out from the backside"
],
"score": [
23
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acfjrs | How do locks and keys work when it comes down to uniqueness? Is every lock-key combination unique? Or could I get lucky and could I find another door or bike lock that matches my key? | Technology | explainlikeimfive | {
"a_id": [
"ed7jk2h",
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"text": [
"Great minds think alike. I may have found yer answer, matey. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Is each lock and key combination unique, or do I share the same house key as a bunch of other people? ]( URL_4 ) ^(_83 comments_) 1. [ELI5: How are keys unique? There must be millions of doors out there. Do \"overlaps\" happen? What are the odds that my key will open a random door in the same city? ]( URL_7 ) ^(_18 comments_) 1. [ELI5: if every lock is unique and requires a different key to open in, how does a skeleton key open any lock? ]( URL_8 ) ^(_6 comments_) 1. [ELI5: is every house key completely unique? How is this done? ]( URL_0 ) ^(_11 comments_) 1. [ELI5: Does every single car in the world have a unique key? ]( URL_6 ) ^(_37 comments_) 1. [ELI5: How do padlock companies make so many locks, yet ensure that your key only opens your lock? ]( URL_3 ) ^(_43 comments_) 1. [How are there enough variations for keys that every key in the world can only unlock it's specific lock? ]( URL_1 ) ^(_18 comments_) 1. [ELI5: How do lock makers mass produce locks that can only be opened with one key? ]( URL_5 ) ^(_12 comments_) 1. [ELI5: How are locks/keys made so that no other key works in any other lock? ]( URL_2 ) ^(_8 comments_)",
"Locks have a set of pins. These pins have a break in them. Keys lift the break in the pins to line up with the barrel of the lock allowing it to rotate. Rotating the barrel then moves the bar of the lock out of the way. Typically a lock will have 4 pins, but there is no limit. I've seen single pin locks and dozen pin locks. So is every combination unique? No. I have a masterlock with 4 pins, it looks like each pin has 10 possible break points, meaning there are 10^4 possible keys for that lock. If they've sold more than 10,000 of those locks there are duplicates out there. It gets more complicated though -- keys also have a shape. You can't just put any key in any lock. Some keys are round, some are straight, some are dimple based....then there are the fancy locks that have discs not pins. Then as locks get old the tolerances get looser. You start finding that keys that didn't used to work start working on a lock. Eventually even a simple screwdriver will turn a lock."
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[
"https://np.reddit.com/r/explainlikeimfive/comments/2rzqx3/eli5_is_every_house_key_completely_unique_how_is/",
"https://np.reddit.com/r/explainlikeimfive/comments/1vb1ev/how_are_there_enough_variations_for_keys_that/",
"https://np.reddit.com/r/explainlikeimfive/comments/4rtx5c/eli5_how_are_lockskeys_made_so_that_no_other_key/",
"https://np.reddit.com/r/explainlikeimfive/comments/2j3gpc/eli5_how_do_padlock_companies_make_so_many_locks/",
"https://np.reddit.com/r/explainlikeimfive/comments/2zkuvz/eli5_is_each_lock_and_key_combination_unique_or/",
"https://np.reddit.com/r/explainlikeimfive/comments/36a6b2/eli5_how_do_lock_makers_mass_produce_locks_that/",
"https://np.reddit.com/r/explainlikeimfive/comments/76jzx3/eli5_does_every_single_car_in_the_world_have_a/",
"https://np.reddit.com/r/explainlikeimfive/comments/18pgm6/eli5_how_are_keys_unique_there_must_be_millions/",
"https://np.reddit.com/r/explainlikeimfive/comments/3omzyv/eli5_if_every_lock_is_unique_and_requires_a/"
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acg4x5 | How do radios work? | I understand how energy travels in waves on a spectrum which includes visible light and like different frequencies of waves, radio waves being one small portion of the spectrum. But then how does a little box of plastic and metal take those radio waves and produce it into audible music? | Technology | explainlikeimfive | {
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"ed7oi15"
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"text": [
"In a radio, there is an antenna which acts as a conductor/receiver of Electromagnetic waves. This EM wave is then converted by the radio circuit and sends it to the transducer (speakers) and is able to output the sound contained in the EM wave."
],
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acjb09 | why do some beverages come in bottles with small caps (like water and coke), while others (usually ice tea and energy drinks) have wider caps? | Technology | explainlikeimfive | {
"a_id": [
"ed8cp2v"
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"text": [
"Small caps are cheaper. Big caps let people sip and smell the drink more, that's better for tea. Big caps also move more drink so people can chug the energy drink."
],
"score": [
9
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ack98h | What does the Disk Defragmenter do? | And how does it increase performance of a computer? | Technology | explainlikeimfive | {
"a_id": [
"ed8juuf",
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"text": [
"Files can be split into small blocks when stored on a disk (to make it so that you can pack a big file in the hole left by many small files for examples). The defragmenter move this blocks together so that the computer can read files in one go rather than having to read a lot of tiny blocks scattered everywhere.",
"Old style hard disks (as opposed to solid state disks) have rotating disks in them that are read by a 'head' which can only look at one little bit of the disk at a time. It takes the head a non-trivial amount of time to move back and forth across the disk. What the disk defragmenter did was put all of the data together so that the head could remain stationary. This meant that the head only had to find the start of the data, and then it could remain stationary while the rest of the data passed underneath it. This allows the disk to read a lot more data in a given period of time. This isn't an issue with solid state disks because they don't have a physical mechanism that needs to move, so they can randomly access data with no penalty.",
"Imagine that you were trying to write a lot of different stories at the same time, but you only had one book. Each time you finish a page, you continue at the first blank page. Over time, your stories are going to get mixed up, and when you want to read a story, you'll keep having to skip pages of other stories, which gets annoying. Defragmenting is like tearing all the pages out, reordering them, and then putting them back, so that each story is separate with all the pages in the right order."
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acki2g | Why is it that if I have two televisions on the same station, there is almost always a delay between the two but if two radios are on the same station, they are always in sync with each other? | Technology | explainlikeimfive | {
"a_id": [
"ed8mwgr",
"ed8oz2j"
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"text": [
"The Radiowaves are always arriving at the same time(given the Radios are next to each other) whereas the TVs mostly stream their Information through a network, and might have a different setting for the Buffer-Size.",
"digital TVs run some computer code to convert the single they are receiving into an image. different TVs will do this at different speeds. Radios is still analog. Which i believe means its converting single to sound at the speed of light (or maybe the speed of electricity). Its doing it essentially instantly. Radio in the US is converting to digital. So in the future, radios might not sync up like they do today. Or since processing sound is less computationally complex, all radios might be fast enough that you don't notice any difference."
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ackitc | Please explain WRAPPING in C# | Technology | explainlikeimfive | {
"a_id": [
"ed8okmm"
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"text": [
"yell its not a hard concept like loops or variable. there is nothing in C# called a wrapper. its more of a technique or strategy. Basically imagine that there is a method that you want to use. Your going to write a program that uses that method dozens of time. As you write the program you might decide that every time you call that method you also want to do something else. For example consider the debug.writeline method. I often won't call debug.writeline directly. I'll create my own function like this > Private void myDebug(string s) > > { > > debug.writeline(s) > > } Later, i might decide that every time i call debug i always want to write to a text file. This way i can have a permanent copy of my debug log. Instead of modifying my code is dozens of places, i only have to modify myDebug. MyDebug is called a wrapper function."
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ackyy7 | how do PC games work? | Each console typically has definite specs: X bytes RAM, Y CPU, Z GPU, etc. PCs can have any of hundreds of combinations of parts and operating systems. How is programming PC games different from programming console games? How do ports to or from PCs (for example, Arkham Asylum to PS3, Undertale to Switch) work? I'm to young to understand this ... Thanks for replying! | Technology | explainlikeimfive | {
"a_id": [
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"ed8xuwz",
"ed8s242",
"ed9c0as"
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"text": [
"A game typically doesn't need to know exactly what hardware it's running on. If it wants to draw something on the screen it'll tell DirectX (for example) \"I want to draw a thing, here's what it looks like,\" and DirectX handles the rest, which involves speaking to the CPU/GPU. The game doesn't care how DirectX does that, just that it trusts it to do it correctly. This is called \"abstraction,\" and is an important principle in software design. Way back in the day you would have to write a separate program for each processor. Nowadays you might write your game in C++, and a compiler will convert that into code for whatever processor it's going to be run on.",
"People described abstraction fine but didn't really get to the root of your question. It's worth pointing out that PC games come with a lot of options to tweak graphics and sometimes physics-related things. They program the game in a way that you can switch on and off certain options or adjust the quality of certain effects. You tell the game how much work it can put into things, and then the game tells your computer to do the work. Basically, the game isn't usually aware of how much your computer can do, so it depends on you to tell it what sort of work to do. How fancy do you want shadows to look? How detailed do you want the texture of objects and people to be? Stuff like that. The computer then works as hard as it can to do the work it's told to do. Typically, it will spit out a processed frame, basically a picture, when it's ready. Most monitors display 60 frames in a second (though of course you can get fancier ones that can display up to 144 in a second) so as long as your computer is able to spit out 60+ frames in a second, you won't notice a problem. However, if the game ends up requesting too much work from your computer, it might only have enough time to spit out, say, 20 frames in a second. You'll immediately notice the choppiness on your screen and probably turn down the settings to make your computer do less work. Typically you design a game with a certain bare minimum specs in mind, a minimum amount of CPU speed, a minimum amount of RAM, etc. You verify that the game can run tolerably with a PC built with these specs. While different parts will vary from there, it's pretty safe to assume that anything more powerful than that will run the game fine.",
"PCs do a lot to abstract programmers from the hardware. Consoles due this too actually. There are essentially middle men between you and the hardware that handle these issues for you. As a programmer of games you just need to think conceptually about hardware. How much total memory do you need? How fast are you going to try to read data from the hard drive? how many computations per second are you going to be doing. Drivers and other middle ware takes care of converting your code into something that can run on the machine's specific hardware.",
"Consoles these days ARE PCs, so there is less difference than ever before in programming them. They are using Intel/AMD hardware just like a PC and run a stripped down version of Linux like a PC can if you want to emulate a console."
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acmwka | why do camera flashes turn on for a second before turning off again and flashing for just a moment when the picture is taken? | Technology | explainlikeimfive | {
"a_id": [
"ed96snu"
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"text": [
"The extra light can help the camera to auto focus in advance of taking the picture, and also make people's irises contract to reduce red eye in the photo."
],
"score": [
10
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acogg3 | why we as a species don't try to populate the oceans instead of keep looking for stuff on the outer space | Technology | explainlikeimfive | {
"a_id": [
"ed9j2r3",
"ed9jd9d"
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"text": [
"It is actually easier to build a space station than it is to build an underwater station. Pressure and the corrosive power of salt water is that big of a problem.",
"Its an “all your eggs in one basket” type of thing that we are trying avoid. In theory we could be hit by a world ending comet or something at anytime, and so long as all humans are on one rock we are vulnerable to that rock disappearing. Also undersea is under pressure, and thats generally harder to engineer for than low pressure."
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acoxnl | Why is 110V the standard for electricity in the United States while in many other countries it's double (220V)? | Technology | explainlikeimfive | {
"a_id": [
"ed9ml7y"
],
"text": [
"Great minds think alike. Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is there a difference in voltage between America and pretty much the rest of the world (240V vs 120V I believe) and what are the impacts of this in terms of energy transport/conservation and usage. ]( URL_3 ) ^(_2098 comments_) 1. [ELI5: Why is there a difference in voltage between America and pretty much the rest of the world (240V vs 120V I believe) and what are the impacts of this in terms of energy transport/conservation and usage. ]( URL_3 ) ^(_ > 100 comments_) 1. [ELI5:why does America and Europe have different electric wall sockets? ]( URL_0 ) ^(_86 comments_) 1. [ELI5:Why do some countries use 110v and some use 220v? Wouldn't it be simpler if the whole world used only one? ]( URL_1 ) ^(_5 comments_) 1. [ELI5: Why is 220v the standard in most countries when 110v sounds easier to produce and should cost less? ]( URL_2 ) ^(_17 comments_) 1. [ELI5: What's the practical difference between 110V and 220-230V standards? ]( URL_4 ) ^(_2 comments_) 1. [ELI5: Why, in the USA, is 110V is preferred over 220V for most things? ]( URL_5 ) ^(_5 comments_)"
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"https://np.reddit.com/r/explainlikeimfive/comments/37q5op/eli5why_does_america_and_europe_have_different/",
"https://np.reddit.com/r/explainlikeimfive/comments/2t9ssg/eli5why_do_some_countries_use_110v_and_some_use/",
"https://np.reddit.com/r/explainlikeimfive/comments/2eg49r/eli5_why_is_220v_the_standard_in_most_countries/",
"https://np.reddit.com/r/explainlikeimfive/comments/3rvezy/eli5_why_is_there_a_difference_in_voltage_between/",
"https://np.reddit.com/r/explainlikeimfive/comments/2ta5g3/eli5_whats_the_practical_difference_between_110v/",
"https://np.reddit.com/r/explainlikeimfive/comments/3mbyix/eli5_why_in_the_usa_is_110v_is_preferred_over/"
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acplhy | link is two screenshots of the same image just slightly zoomed in. Why do you get the expanding checkerboard pattern when taking a picture of a screen and how does it develop thru a screenshot? | Technology | explainlikeimfive | {
"a_id": [
"ed9rxz7"
],
"text": [
"It's a Moiré pattern ( search Wikipedia for it). Your screen's pixels form a grid. The pixels of your camera form a grid. When you put two (or more) grids over each other imperfectly - be it two chain link fences or a photo of a screen - you get Moiré patterns"
],
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acptow | How does the defrost lines on the rear window of my car work? | Technology | explainlikeimfive | {
"a_id": [
"ed9tsos",
"ed9wpvn"
],
"text": [
"They’re basically just very thin wires. Pass an electric current through them and they get hot. Presto, your window starts to heat up and defrost/deice.",
"Every time energy changes form (or direction), some of it is lost to heat. This applies to electricity as much as any other form of energy. Most of the time, we search for ways to avoid losing our energy to heat, partly because we then have to come up with ways to deal with said heat, but mostly because that's energy we can't use. Sometimes, heat is the entire point. Light bulbs are a good example - it's just a wire that's heated up so much it gives off light. The more energy you run through it, the more light it gives off. That's why they were measured in Watts... which is really just a fancy way of measuring generated heat. One of the easiest (and most efficient) ways of generating heat, if that's your goal, is to resist the flow of electricity. How much a thing resists electricity is known by the term resistance. Perversely, the less resistance there is, the more heat is generated due to how Ohm's law works... but that's a bit beyond the scope of this comment. Heater strips on your back window are just lines of a paint that conducts electricity - with resistance. Just enough (lack of) resistance to get them nice and toasty."
],
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acqm1k | Once we are able to 3d print records (vinyl) will it be digital or analog? | My 17 year old son just asked this question and I have no answer. | Technology | explainlikeimfive | {
"a_id": [
"eda0ded",
"eda1ke9",
"eda0h10"
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"text": [
"Analog. There's nothing digital about the records themselves beyond the fact that a digital file was used to print the record. Which is a pretty inefficient and expensive way to make a record. It's no more digital than vinyl records produced today being initially made from audio tracks recorded digitally.",
"Digital audio really means that it is stored in a numerical representation. Analogue audio is a direct representation of the physical pressure waves, stored as grooves in a vinyl. It's literally an analogue of sound. I would say analogue. Since the audio data (digital) has been rendered to an audio wave (analogue), the 3D printed vinyl will have the audio wave on it, albeit aliased due to the 3D file not having infinite resolution. I have a few NES soundtracks on vinyl, and even though it's a bunch of square and triangle waves (along with white noise), it's all analogue, since it's not storing the audio data in a numerical representation.",
"Analog. Digital information is stored as 0's and 1's, as discrete values, while analog is stored as a continuous set of values. A vinyl record works by having a [physical engraving of the audio waveform]( URL_0 ) that the record player converts into audio. The physical waveforms are an example of analog data storage, as no 0's or 1's are involved"
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acrnbw | How quickly nurses read ultrasounds | I've noticed in movies/irl that nurses/doctors tell suuuuuper fast what the sex of the baby from the ultrasound, whereas the pregnant person or even myself can't really decipher from just a photo. Is there some specific significant thing in an ultrasound that gives the babies sex away? | Technology | explainlikeimfive | {
"a_id": [
"eda8ov9",
"edac9bu"
],
"text": [
"Basically they are looking for a penis. My mom always said they were looking for \"turtles with tails. \" If it looked like a turtle with a tail, it was a boy. If there was no tail=girl.",
"They pick it up with practice, but some ultrasounds are easier to read than others. I had a pregnant friend who had to go back in again a week later because the nurse couldn’t tell the sex in the first ultrasound because of the position the baby was in."
],
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6,
5
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acrzqc | What exactly is a mechanical keyboard, is it something different from the kind of keyboard on a laptop or the kind of peripheral laptop you get at Staples? Is there something better about it? | Technology | explainlikeimfive | {
"a_id": [
"edacmra",
"edah51o"
],
"text": [
"Mechanical keyboards are distinguished in contrast to \"membrane\" keyboards which use a flexible membrane to separate two layers of conductive material from touching with small \"bubbles\". When pressure is applied to the raised areas of the membrane it completes the circuit and signals a key press. This is really cheap to produce and so it is most commonly used, but it feels spongy and wears out relatively quickly. In contrast a mechanical action for each key provides a better ~~tactical~~ tactile experience at the cost of.. well, cost.",
"In a membrane keyboard, a key press registers the moment the key bottoms out. In a mechanical keyboard, the key press registers half the way down. There are many differences in used materials and technology - but this is the one difference you will actually feel when using the keyboard. It's a very small difference that the regular user might not even notice. But if you type a lot, very fast, every day - not having to press the keys to the bottom - but just halfway (not hitting the stop/resistance at the end) - can help you type faster with less finger fatigue - and might even help a little bit with RSI. And competitive gamers often like mechanical keyboards, simply because a keypress triggers just a tiny bit faster/earlier. The actual difference between a mechanical and a high quality membrane keyboard is pretty small though."
],
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acuu19 | How does WhatsApp compress videos so quickly? When done in software like Premiere Pro, it takes minutes, but WhatsApp does it in seconds. | Technology | explainlikeimfive | {
"a_id": [
"edbackh"
],
"text": [
"Poor quality/low bitrate = fast compression. If you don't care about saving all the info, compressing videos is easy."
],
"score": [
4
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"text_urls": [
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|
acuypg | Why do certain bugs and glitches appear on seemingly random occations in some programs? | What I mean is that there should be a trigger for such events. And if faults in the codes can appear at complete random, why? | Technology | explainlikeimfive | {
"a_id": [
"edb0dry"
],
"text": [
"The dont appear at random, but after a series of events / when the game is brought inr a certain state that triggers the bug. Games and programs are made so complex these days, that its nearly impossible to test each and every permutation / state the game can be in"
],
"score": [
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acx5bt | When a new computer has its battery fully charged and is properly shut down, 2 weeks later the battery is at 0%. Where does all that energy go? | Technology | explainlikeimfive | {
"a_id": [
"edbk2vz",
"edbsuzj",
"edbuqig"
],
"text": [
"Many devices have need to utilize power even when it is completely shut off, things like the internal clock. These will continually drain the battery, though generally slower than your normal usage, until there is no power to be had. If your battery normally holds an 8 hour charge with constant, heavy use, then the low-power shutdown mode is using maybe 2% of the max power to drain in 2 weeks. If that same heavy use kills your battery in 3 hours, then it's less than 1% usage in this mode. But almost no modern devices turn *completely* off, and instead draw little bits of power to do things like see if the power button is being pressed, or run the GPS chip so the NSA can find you.",
"Batteries lose a small amount of charge to the air. It's a tiny amount but it's not insignificant. Also nearly all modern computers have a soft power switch, not a mechanical switch that physically disconnects the power, so even when it is completely and totally shut off, it's still using a tiny amount of power to run the circuit that detects the push of the power button.",
"All rechargeable batteries have a certain level of internal discharge, and leaves the battery in the form of heat, but not fast enough for the temperature of the device to heated up to a degree measurable by consumer equipment. On top of that, your laptop probably doesn't have a power switch that physically breaks the connection to the battery, so the circuit that detects when you press the power button stays powered, drawing a minuscule amount of power. Edit: Read in the comments that you do have a switch that that breaks the circuit. That's really weird, though. What sort of a laptop do you have that's got that? Many laptops also draw power from the rechargeable battery to keep its real-time clock ticking, only switching to the non-rechargable coin cell battery when the rechargeable battery is empty or disconnected. However, losing all of the battery's energy over the course of just two weeks sounds unusually fast, unless it is a very low capacity battery. If it's an old battery, its maximum capacity might have been reduced significantly over the years."
],
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acy3jr | Based on what kind of technology are hackers’ internet activity safe from national security and the government? | My question is based on the latest events with the Dark Overlord hacker team that still has a Twitter account that is “threatening” to release stolen documents. How are they not able to trace them/based on what kind of cryptic technology are they getting away with it? Another example is Anonymous. | Technology | explainlikeimfive | {
"a_id": [
"edbsb9w"
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"text": [
"There are many ways to keep your internet actions safe. The first and most basic is a VPN, which encrypts all traffic between you and your destination so nobody can read it. Then you have TOR routers which break up your internet traffic and bounce it all around the world before it reaches its destination. Finally, you can spoof fake Mac and IP addresses. These aren’t all the tools that people use and they aren’t all foolproof but people have gotten really good at hiding"
],
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acznaz | The difference between functions, methods, objects, classes, and OOP languages. | I can't wrap my head around when to use which, or why they are used. Also, what makes an object oriented language different from the other type. How does it go about doing the above? | Technology | explainlikeimfive | {
"a_id": [
"edc72p0"
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"text": [
"A *function* is a block of code which runs some commands and can be called on from elsewhere in the code. example: def function(): print \"I do something.\" # now we can call the function from other code, like this, and it will always print \"I do something\". function() A *class* represents an object. A thing. It can contain both *data* and *functions that operate on the data*. A function which is attached to a class is called a *method*. It can only be called through the class. So, for example: class Car(): def __init__(self): self.model = \"Honda\" self.color = \"red\" def drive(self, destination): # do something henry = Car() henry.drive() in this example, I have a \"car\" class with two attached methods. One of them, __init__, is something used by python to create the object. The other one, drive(), does something about driving. then i created an *instance* of the car class, and called the method 'drive' on the instance. So: function() is a 'function', meaning a block of code that can be called from elsewhere and run when it is called. 'Car' is a *class*, which is a collection of data and functions that operate on that data; the functions contained within a class are called 'methods'. So *drive* is a function contained within Car, meaning it is a method."
],
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ad1cx7 | If we have CGI that is so good that it looks almost indistinguishable from real life in films and television shows, why can't we have the same level of realism in video games? | Technology | explainlikeimfive | {
"a_id": [
"edcmjg1",
"edcmo7x",
"eddjpn1"
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"text": [
"A single frame from a Dreamworks film can take days to finish rendering. A video game has to render 60 frames in a single second.",
"Film and television have the advantage of having hours upon hours to render (do all the fine calculations that make it look so good). Video games have to sacrifice quality for speed because the graphics calculations are done on the fly.",
"Consider a film and computer game as animation... To make a film, someone had drawn each frame they want to show you in advance, and then show you them all in order like a flipbook - they are allowed to spend as much time as the they want drawing each picture (and can even get help from other people to do some of the drawings or help colour them in) so the quality of the drawings can be really, really nice. To make a game, the animator had to sit with you, showing you the first picture, then asking you what you want to do next before drawing that picture to show you, then the next, and so on... Because one animator can only draw so quickly, they can't put the same detail into the picture and the pictures won't look so good. Instead of having someone drawing stuff, we use massive computer arrays now with people working then - having a while array of computers taking the time to draw each frame in advance means it has the potential for life like quality, while your home PC or console needs to process and draw each frame in real time as you direct the game with your input, which means we are limited in how much detail we can show."
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ad2xny | Why is deep sea exploration so difficult? We have had the technology for a long time, has it reached some kind of plateau that scientists cant figure out? | Technology | explainlikeimfive | {
"a_id": [
"edd4ubw",
"edd4hgu",
"eddvxv7"
],
"text": [
"The difficult part is getting the funding. The engineering has been figured out for a long time, but no one has quite figured out how to finance non-military applications of it. Historically, exploration has been dependent upon either political will or financial incentive. At the moment, both are lacking with regard to deep-sea exploration.",
"Too much is spent seeing how man can go deep instead of how deep man can go. The future of undersea exploration lies in man controlling machines, not building machines for man to explore in",
"long, even for an attentive 5 year old: As others said the basic engineering exists, but the application is expensive because of the high need for safety and quality assurance, water is also thicker than air, by a lot, and salt water is corrosive. high pressure: A garden hose is around 3 bar, a full on fire hose works at around 20 bar, the average deep ocean floor (called the abyssal plain) is under 6000m of water or around 600 bar of pressure (every 10m of water is roughly +1 bar of pressure). Any tiny hole in any non pressurized chamber or enclosure would turn into a hydrocutter lance enlarging the hole rapidly and fill the room with water in seconds if it doesn't rip the entire machine to pieces. So every part, component and process needs to be checked and tested to possibly higher levels than space components. Look at the air leak in the ISS recently, first mild controlled panic then problematic but solvable but lastly never life threatening if you remain calm; such a sudden hole in a deep sea submarine would be immediately mission ending if the sub even stays in one piece long enough to rise to the surface. The main user for air is humans, remove the humans and it becomes cheaper, electricity still doesn't mix with water but also doesn't need air so it is easier to keep safe, and coolant is all around you, but this leads to another problem: (reminds me of a morbid joke: Is it cheaper to send fresh air and and water or to send fresh astronauts?) water is thick: lots of current use cases for robotic exploration is oil companies involved in sea exploration and maintenance already make a lot of use of this. The biggest problem is that you can't really send radio through water, simply put it is too thick (ELF waves can be used by submarines but they are really slow and more like simple wake up calls than real communication), so they need to use cables, luckily the same thickness of water makes it easier to suspend long and large cables down in water, but it is still a large distance and cable is expensive and prone to getting tangled up and snagging, like the charger cords in the drawer. sadly fully automonous robotic submersibles aren't yet smart enough to work by them selves, that would be awesome though. lastly corrosion: salt water almost literally eats metal, high pressure salt water is even more corrosive, so lifetime is short and that is also expensive in spare parts and new devices, checking coating, repairs, repainting, etc."
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ad32qb | What is the difference between a Blue Screen of Death on Windows and a Kernel Panic on Mac/Linux? | Further, what is the main reason these happen? And does a similar form of these shutdown errors occur on all computers, like smartphones? | Technology | explainlikeimfive | {
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"The kernel have the job of managing other tasks on the computer. If they fail, the kernel will kill them and maybe restart them. No biggie. But the kernel can't restart it self, so it just gives up. Most kernel error are (or used to be) crappy hardware drivers, that need permission to run on the kernel layer, because it's the only place you access to everything on the computer. But to answer you question: it's the same thing, by different names and can happen on all computers",
"Simple answer: The way it's caught. Both are when an issue with a driver or the kernel in kernel space crash, often spectacularly, to the point that the system can not recover from it in any way. The nuclear version of an error. Windows shows this by dropping to recovery, showing an error message while it attempts to log, diagnose and attempt a fix. Linux shows this with the famous \"Kernel Panic\" message. Usually, a Kernel Panic on linux means the system is too unstable to even boot correctly."
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ad5vsy | Why is it that almost all cheap earphones happen to end up with only one ear bud working? | Technology | explainlikeimfive | {
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"Cables are cheap, so they wear out quickly, however it’s unlikely that both cables give out at the same time Keep using them, and if the first broke quickly, so will the other lol",
"A few years ago my apple earbuds stopped working on one side within 2 months. Those things aren't cheap :/"
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ad64x6 | Why does an app require me to free up 200 mb worth of space when it is only a 12 mb app? | Technology | explainlikeimfive | {
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"The same reason you need a whole table to play a board game even though all the pieces can fit in a small box.",
"In simple terms, the executable will be 12MB, when it is compiled (when the code to run the application is \"converted\" into a form your phone understands, literally millions of 1s and 0s). But the executable itself can create files as well, such as \"cache\" files (storing data to make the app run faster), or configuration files. These all add up. My guess is the operating system has been set to allow a 200MB \"growth\" of this app. Whether the creator of the app knows this ahead of time or not, I'm not sure but that would be my logical guess."
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ad7ovy | Why do only some nuclear explosions produce the stereotypical mushroom cloud? | Technology | explainlikeimfive | {
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"The formation of a mushroom cloud is about the amount of energy released into the atmosphere. You can create a mushroom cloud from non-nuclear detonations as well, for example volcano. The same mushroom clouds are also generated on hot days where you have solar energy constantly heating the ground, however these mushrooms can take hours to form instead of seconds and do not carry the visual debris."
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ad8ly4 | How were films edited before Computers? | Technology | explainlikeimfive | {
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"text": [
"They would physically cut and re-tape the film. The phrase \"On the cutting room floor\" comes from this.",
"Fun addendum to these answers: in the early days, editing was not considered an important part of the process; indeed, it was considered busywork. It became an easy way for women to be involved in the biz, because editing was considered comparable to sewing. Once the men realized what editing could do that came to an end."
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adc2v1 | how are daily contact lenses made? | Technology | explainlikeimfive | {
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"text": [
"Contact lenses are injection molded like any other plastic product. They are made from a highly detailable PDMS material."
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adccib | If the amazon echo doesn’t start processing audio until you say “Alexa”, how does it know when you say it? | Technology | explainlikeimfive | {
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"To put it as simply as possible, this is the process that happens: 1. There is a chip that is always listening in the echo. It doesn't record, doesn't transmit to Amazon. 2. When this chip hears the wake word (Alexa, Amazon, Echo or Computer, whatever you have set) it activates a buffer, recording a bit (less than a few seconds) 3. This is sent up to Amazon where their better processing (their servers are obviously more powerful than an echo) verifies the wake word was said 4. If the wake word wasn't said, the buffer is purged. If not, the buffer gets analyzed along with any continued speech for commands The buffer is used so it is smooth, otherwise, you'd have to say \"Alexa\" wait for it to verify, with a pause, then state your command. The couple second buffer allows smoother \"Alexa, turn on the lights\" type commands",
"There is a special circuit which is listening to everything waiting on \"Alexa\". When it hears that word it will wake up recording and language processing for the rest of the speaking, but until then it is just that single chip which can only recognize \"Alexa\" and records nothing.",
"I like to think of it like a dinner party - you are constantly able to hear what everyone else is saying at the table, but you don’t pay attention and actually listen until you hear your own name. Alexa works similarly, ‘hearing’ what you say (through a looping recording process), but not really listening until you say the wake word.",
"It's always listening *locally* without recording or sending ~~days~~ data over the internet to the cloud servers until it hears the wake word. Then it starts sending all audio up to the cloud for processing.",
"They say it only records a loop of, I think 2s, constantly overwriting itself. So it is always listening, but its not saving the audio, just keeps 2s at a time and checking if \"Alexa\" is in that snippet. If it detects the wake word in that snippet, it will wake up and start recording. Of course even if that is 100% true, they aren't 100% accurate in detecting the wake word, and it can be woken up and start recording on other similar words. No matter what, I personally would never put one in my home.",
"I just read the article in the link below, and apparently you can access all recordings from your Alexa on the app. URL_0",
"There are 2 different listening programs. One is very simple, only understands a few words (the \"wake up\" command) and is permanently running. It listens for a few seconds, if it doesn't hear the key words, it deletes whatever it recorded and starts again. Over and over. Once the first process detects the wake up command (Okay Google, or Alexa, or whatever) it launches the second process. The second process connects to its parent server cluster (Google, Amazon, etc) through the Internet, and is ready to accept your command. Of note, the little gizmo in your home isn't actually powerful enough to translate your speech to text and search. All it does it record the sounds and send it back to a big server cluster somewhere for the heavy lifting.",
"It is always processing audio - the Echo is always storing the last ~10s of audio and looking for a hotword (\"Alexa\", \"Amazon\", etc.). After it finds the hotword, it starts recording. That recording is then sent off to an Amazon server somewhere and fed to a neural network that transcribes it into actual words. From there, another server parses your command and does the things necessary to make it happen (communicating with your lightbulbs, ordering a package, or sending some music back, for example). The only difference between before and after you say \"Alexa\" is the Echo connecting to an Amazon server. Keep in mind that the ~10s audio buffer is only stored on your device - it's only after you say the hotword that your voice is recorded by Amazon.",
"Why can’t it be “Janis” instead of “Alexa?”",
"The better question is, why doesn’t Alexa recognize when the commercials say, “Alexa?”",
"Here is something to think about. On Android, there is a little software you can chose to install. Basically when a song plays in the background, it will show the artist and title on the lock screen Obviously, I freaked out that it's listening all the time. It is, but it does it offline. Takes about 500mb. Now, it does it by finger printing. 500 mb and it recognizes most songs. Just imagine how easy it would be to finger print most basic words, expressions and so on. Like \"family Guy\", \"new TV\", \" I like the new Ford\" and so on... I would bet money they do know what you are talking about..",
"To anyone that thinks it's sending a constant stream of audio to Amazon, you are delusional, mostly. I don't dabble in the tech, as much as i know how much data it takes to record and store audio, it would not be worth it to save your audio at any point. On the flipside it's entirely possible/probable that based off of your digital footprint, they are collecting certain words and phrases in order to sell you products via targeted ads and marketing Facebook does it, as do many other devices, mostly from your own phone. Try it out sometime, it's creepy. I have an android phone for work, logged into my Personal Gmail. A coworker and I were talking about Volkswagen one day at work, when I came home and turned on my Android Sony TV, there was a Volkswagen ad. Tried it over and over with success. Also did this with Facebook on an iPhone, same result. I have over 10 devices listening to me right now, have had at least 1 (pc) that has been since 1995, that's a lot of audio. Let's say 1 hour of audio is 20mb (this varies by bit rate and audio quality) Let's say... 24 hours is 480mb 1 week is 3,360mb (3.36gb) 1 year is 174,720 mb (174.72gb) That doesn't seem like much Multiply that by (126,220,00 households in the USA alone, and you get 22053.1584 PETA BYTES That's way too much data to extrapolate 24/7 recording. Regardless of what Big Brother does with the audio it swipes off the NSA feeds, Little brother just wants to know if it should advertise you tampons or poopourri. (That math was a ballpark, if someone has better math, I'd be down to see it.) TLDR: No one is recording your audio to use against you, although the NSA. has access to a lot of these feeds and can pull audio from them if you are saying \"terrorist phrases\" (thanks Snowden)",
"Google records before you say \"ok Google\". You can verify by going to your saved voice commands at my URL_0 . You hear yourself saying the trigger before saying the command. Filter the products with voice at the bottom.",
"Don't believe anything! It's listening to everything!!!!!! I'll sell you a special aluminum hat so it can't read your thoughts, only 100$.",
"I wish you could customise the Echo/Google trigger phrase. I'd love to be able to say 'hey man' (or something casual but less easy to accidentally activate) instead. I'd feel like far less of a dick lol"
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adco9s | Why do some greenscreens look painfully obvious and lower quality than others? | Technology | explainlikeimfive | {
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"text": [
"A myriad of reasons ranging from a poor camera setup and staging/lighting of the green screen plates to limitations of the vfx software/compositor skills in pulling a decent key of the foreground object. There are relighting/edge blending issues that also have to be addressed when combining the foreground fill/matte and background plates to achieve a high-quality result.",
"Bc some people rush through and basically just copy and paste the picture in in the background while others take their time"
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adfkh0 | How is Betamax different from VHS? | Technology | explainlikeimfive | {
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"text": [
"Betamax had slightly better picture and sound. The main downside was that only Sony could make Betamax equipment so *everyone else in the industry* put their weight behind marketing VHS equipment, giving you more selection and lower prices. Lower prices won."
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adgdry | What Exactly Causes Phone Screens to Bleed Purple? | I dropped my phone recently and cracked my screen. I noticed afterwards a little bit of purple around the edges that slowly sort of seeped and bled into the rest of the screen almost like a liquid. I've heard of this happening (edit: and also understand that I need to get my screen replaced) but I've never understood what the explanation behind it is. Thank you! EDIT: I have an Optic AMOLED display. | Technology | explainlikeimfive | {
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"text": [
"Broken liquid crystals. you have an LCD or Liquid crystal display. Imagine a substance with some of the order of a solid and some of the fluidity of a liquid. What you have is a liquid crystal—a kind of halfway house in between. At any given moment, liquid crystals can be in one of several possible \"substates\" (phases) somewhere in a limbo-land between solid and liquid."
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adhakp | Is there a reason why all or most IP addresses begin with 192.168..? | Technology | explainlikeimfive | {
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"192.168.x.x is part of the 'private' range of addresses set aside by the Internet masters (APNIC). Whilst these are valid addresses, they are specificically designed not to be transmitted across the wider Internet. There are actually 3 such sets, (Class A, B and C). These are: A: 10.0.0.0 to 10.255.255.255. B: 172.16.0.0 to 172.31.255.255. C: 192.168.0.0 to 192.168.255.255. The Technical term is '[Non Routeable IP addresses]( URL_0 )'",
"First you need to understand the difference between public and private IP addresses as well as the term routable. Private IP addresses are used internal to your network and public IPs are used external also known as routable. You may have 50/100/1000s of devices inside of your network they can all share one public IP address via Network Address Translation and the use of port numbers. If you google “what is my IP” you’ll see a much different ip address. That is your public IP and it’s how you talk to the world. This is dynamically assigned via your ISP. The best way to put it is this, your house has a unique address: 123 Main Street, city State zip code. No where else in the world does that address exist and it’s how UPS knows to find you. Now inside of your house you probably have tons of things that everyone else has. UPS doesn’t need to know where your fridge is to deliver you packages for the fridge just how to get to your house. This all exists because there is a limited number of IPv4 address so every routable IP can have thousands of Private IPs behind it. There are three private spaces: 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 I’m not 100% sure why most retail devices went with 192 as the IP range. Technically they could have used any of them. In my house I use several different subnets with the use of Vlans. 192.168.98.0/24 vlan 998 management 192.168.99.0/24 vlan 999 Lab 192.168.100.0/24 vlan 1000 Home Network 192.168.101.0/24 vlan 1001 IOT 192.168.102.0/24 vlan 1002 Media 192.168.103.0/24 vlan 1003 Cameras Vlan 1004 retired 192.168.105.0/24 vlan 1005 Servers 192.168.106.0/24 vlan 1006 NAS That’s about the basics of a network. I’ve been a network security engineer for about 10 years.. it’s a really amazing career with lots of jobs and the entry is minimal. Hope that helped. Edit: also understand most things in Network were developed 20-30 years ago when not many home users had internet. That is why 127.0.0.0 range is reserved.. the thought was we would never run out of IP address.. and it’s why IPv6 is becoming the new standard.",
"192.168.x.x is reserved for [private networks]( URL_0 ), i.e. your local network (for your home, office etc.) In some places, each device could also be assigned a public IP address (for accessing the internet), or all the devices in the network could share the same public IP address using [NAT]( URL_1 ).",
"These are internal IP addresses. If you are on a home network, you will have this IP address. Even if you have one computer on a wireless router connected to a modem, you are on a home network."
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adlt7g | Why do phone batteries degrade over time such that they go from 100% to 1% very quickly, but can continue to run at 1% for hours on end? | Technology | explainlikeimfive | {
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"Nearly anything that uses fuel has a \"reserve\", an amount below empty that's there in case you plan badly. Cars have the same thing with their fuel gages. You can get a fair amount of distance out of it when the gauge says E.",
"The digital readout in phone batteries or other things that run on fuel (as u/DaSaw said in his car example) are more or less guidelines. My four year old phone would die almost a minute after it hit 3%, but took almost an hour to go from 100% to 97%. Both were technically a \"3% difference\", but the phone isn't actually showing you what the available power is. It's running an estimate based on what you are currently doing (playing games, listening to music, making calls, or just having it off in your pocket). That percentage is just the phone trying it's best to tell you how long you have left if you \"keep doing what you're doing\", which is why sometimes it jumps percentages very quickly. However, I don't know if this is how all phones work, so someone with more experience in phones specifically may need to chime in. & #x200B; On the same note about car fuels, my current car is badly calibrated, and will read a little past full until I'm at about 75% tank. It will also read empty starting at 25% tank. Depends on the car sometimes. As well, a car runs on fumes, not the gas. It may display empty and may be correct (no gas left) but can actually go pretty far on just the fumes that are left in there."
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adm8dw | How is USB-C capable of transfering so much more data and power than previous versions of USB or other interfaces? | Are there simply more pins, more wires, and better shielding? | Technology | explainlikeimfive | {
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"For the data, it's two part, but first, USB-C does not mean faster data, USB3 does, some USB-C cables are USB2 only. Anyways, the USB3 ones have the extra pins of the USB-C connector hooked up to superspeed wires, there are 4 pairs of superspeed wires, and they have tougher requirements than regular USB wires (basically, lower noise wires). As for the extra power, the USB-C connector requires that the cable has power wires that can handle at least 3A (more than the ~2.1A that regular USB cables are typically capable of). On top of that, protocol changes were made that allow the voltage to change past 5V (something some of the cell phone chargers already do, even with old USB cables). But USB Power Delivery allows the voltages to go all the way up to 20V and the currents up to 5A which together allows for 100W."
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adsd92 | How does Spotify know which types of music I might like? | Technology | explainlikeimfive | {
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"text": [
"Simple answer, it tracks what music you listen to and is able to extrapolate what you like from the list of things you play. Longer answer, this is a study called semantic audio. It's all about taking objective measurements of a signal to create identifiers, then connecting it to other measurements like how often you listen to tunes with the same or similar identifiers and then using probability and statistics to find things that are similar that you haven't listened to. Some of those things are baked into the metadata of the files, like genre or artist. Spotify employs people to categorize music by listening to it, then the algorithms are designed to make the connections automatically. Other things are computed, like tempo, instrumentation, song key. That kind of engineering borders on black magic. Then it's all fed into a machine learning system that adapts to users' tastes and feedback, as well as focus groups and trained listeners to tune the algorithms. It's a very complex and sophisticated system with many layers, and the technology overlaps with track identification and source separation.",
"I knows what you are listening to , the more you use spotify the better the selection gets."
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adu8ww | How were the maps made accurately before the technological advancement? | Technology | explainlikeimfive | {
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"text": [
"They literally walk everywhere and charted what they saw. It took a massive amount of time, but it got the job done as accurately as they could have during that period."
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adydi6 | How does 'Incognito Mode' work for Google Chrome? | Technology | explainlikeimfive | {
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"text": [
"It's doesn't save anything on your computer. No cookies or history. It's only for porn basically. You will not be hidden on the web.",
"Incognito mode does two things: 1. It creates a new browser session, which means it doesn't use any data from your main session. So any site you go to doesn't \"remember\" who you are for this session. 2. It doesn't keep any history, so the moment you close the window there's no record of this browsing session *on your computer*, including history and other data such as cookies. This also makes incognito useful if you're using a friend's or a public computer, so you don't have to log them out of whatever services they're logged into if you want to use your own login, and it makes sure that you'll be logged out once you close the window."
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adz40x | What is an atomic clock and how does it work? | I watched a short YouTube clip of someone explaining how GPS works (ELI5 style) and they mentioned atomic clocks in the satellites. He explained that since all the clocks are atomic they are all naturally synchronized. So what makes an atomic clock so accurate? How does it actually work mechanically? | Technology | explainlikeimfive | {
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"text": [
"Clocks are just mechanical devices that utilize a consistently repeating pattern. A pendulum for example has a predictable repeating pattern, but those can go out of sync from things like bumps. Well, atoms oscillate. Its a type of angular momentum, as though they rotate in 4 dimensions giving us a sinusoidal cutout. The frequency of this oscillation is very very very unique and reliable, so we measure that! Little more engineering and quality manufacturing goes into it, so you wont be getting one at target, but when accuracy is necessary for experiments, these are top notch.",
"If you excite a atom they release radiation at a constant frequency and the frequency depend on the atom. Colors in neon light work on that idea. You mix gases with that releases difference colours to create the light in neon tubes. So atoms generate electromagnetic radiations with fixed frequencies so a single colour of light have a fixed number of peeks and valleys each second. If you could build a device that could count that peeks you have a clock. Atomic clock excite specific atoms so they generate a microwave radiation at a fixed frequency. The by counting the peek you can determine the time that have passed. A second is define as as the duration of 9 192 631 770 cycles of radiation corresponding to the transition between two energy levels of the ground state of the caesium-133 atom. So you excite the ceasium-133 the correct way and count the peeks in the radiation. When you have counted 9 192 631 770 peeks a second have past."
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ae0c57 | How is quicksaving in a game different from a normal save, and how does it work so much faster? | Technology | explainlikeimfive | {
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"text": [
"Quicksave stores the save information in the system's working memory (RAM). Saves that take longer get saved to the system's permanent storage (HDD, SSD, SD card etc). & #x200B; That's why quicksaves tend to get lost when you reset the game or turn the device off."
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ae218h | What is Optane Memory? | ELI5: While looking for a gaming PC I saw a Dell computer with 12 GB of RAM + 16 GB of "Optane Memory." What is that? | Technology | explainlikeimfive | {
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"A solid state drive used to cache a hard drive. At a software level, some files identified as frequently used, and/or some pending writes will be written to the SSD for quick access (and later written to the hard drive later for the latter).",
"It's basically persistent RAM. It's super-high density, super-high bandwidth persistent memory that your OS can use to store commonly-used files and programs to help them open more quickly by shortening cache times."
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ae2br0 | Google charges 10$ for 100gb of storage but offers TB’s of storage free in google photos how is this possible? | Technology | explainlikeimfive | {
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"text": [
"Google photos is actually a training set for their image recognition software. Having a virtually unlimited supply of photos means they can beat the socks off everyone else. You are doing them a favor."
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ae2pcf | How do website servers work and how do you access data from it? | Technology | explainlikeimfive | {
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"Web servers are just computers connected to the internet that have someone's (or, more likely, many peoples') website files on them. They have special software that sits and listens until other computers (like yours, for instance) ask for one of the websites they host. Your browser (Google Chrome, Mozilla Firefox, Microsoft Edge, etc.) is another piece of specialized software that knows how to ask these web servers for some of their data. When you type in URL_0 to your browser, a massive internet \"traffic directory\" called DNS tells your browser which web server out on the internet has the files for URL_0 . Then, your browser uses that address given by the DNS and asks the correct web server for the data - and the server sends it over! Your browser takes that data and (usually in a matter of fractions of a second) assembles the web page for you to view.",
"A very simple version is a server running Microsoft Internet Information Server (IIS) software. On a MS IIS server, you set up a folder on one of the drives (the default is C:\\\\wwwroot) and you put your main page in there (index.html was the original, so I'll stick with that), and you could keep files in subdirectories in the wwwroot. so if I'm genxcub dot com (spelling it out so it doesn't make links), and I have a special page to sign up for my notification service. I keep the files in c:\\\\wwwroot\\\\notification, and you, in the public would go to genxcub dot com / notification (the names match). & #x200B; So at the most basic, when we go to a webpage, we are being invited into a secured directory on a server and we're just reading files. Our browser knows what files to display for us without us having to choose them. The http protocol defaults to using port 80, so we are going to a public IP address on the internet that is listening on port 80 for our browser to ask permission to get into the IIS folder (and then it lets us do it)."
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ae2qu7 | Why do older "grindhouse" films have vertical green lines sometimes? | I'm watching "Lovely but Deadly", made in 1981, but with really bad film stock. This looks like classic grindhouse cinema. Bad editing, hair on the film, etc. This movie is about as well-preserved as your grandparents super 8 home movies. I noticed this with numerous films of the era. Why do sometimes I see vertical green lines on the picture? Sometimes you see it just for a few seconds, sometimes it's a whole scene. What's the technical explanation for these green lines? | Technology | explainlikeimfive | {
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"Vertcal lines on film are scratches on the surface of a film print. This can be due to the print running over some dirt, a stuck roller, or any stationary object in the film path. For this reason, areas handling film are usually well-maintained and very clean. On film stock, there is an 'emulsion' side, where the image is printed, and heavy scratches can look green as most of the emulsion is scratched off the film. If the scratch is lighter, it will appear black instead. Source: I was a film projectionist, and accidentally caused a few scratches in my time."
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ae40p7 | Why did older game consoles only worked on channel 3 ? | Technology | explainlikeimfive | {
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"Great minds think alike. I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELIF: Why we had to turn to channel 3 in order to play video games? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: Why is/was channel 3 the channel to tune into for cable and satellite television? ]( URL_2 ) ^(_5 comments_) 1. [ELI5: When I was a kid, why was channel 3 the chosen AUX/input for most game systems or VHS players? ]( URL_0 ) ^(_7 comments_)",
"It had nothing to do with the console. Your old TV only recognized a different input, whether it was the VCR or a console, on channel three. This is due to analogue connections rather than the digital switching going in modern television sets.",
"They didn't, there was a second channel (iirc ch 4) you could use. Choose whichever doesn't have a competing on air broadcast"
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ae48zq | What are the advantages and disadvantages of fixed and floating point calculations on computers? | Hello I know what fixed point and floating point values are. But I can simply not understand *at all* what advantages the one has to offer over the other. Thanks | Technology | explainlikeimfive | {
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"text": [
"Because some decimal numbers can be extremely long, i.e. pi. It's hard to represent that with fixed point arithmetic, and even tho it's impossible with floating-point, it's still better suited for it"
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ae6djt | How does something like this really work? | Technology | explainlikeimfive | {
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"A quick glance at that page suggests that it uses [ultraviolet germicidal irradiation]( URL_0 )(UVGI) to get rid of the germs. The way that works is pretty much the same way you get skin cancer. By blasting the germs with UV light, you're trying to disrupt their DNA in order to either kill them, or disrupt their inner workings enough to make them harmless. We've been doing this for around 70-ish years now, and it's been shown to work. The part where it doesn't fall off of the bed is probably very similar to how a Roomba works. But I doubt that's what you're interested in. As for whether you should back it or buy it, well that's a decision you'll have to make on your own. I, myself, am mildly sceptical, and advice you to take a good look at the third party that tested it, and how reputable it is.",
"Yes, it is. The same properties of UV light that can damage your skin and lead to skin cancers also kills bacteria. Specifically, UV-C light (a band that's completely absorbed by the earth's atmosphere and therefore is never encountered by humans at scale) exerts a powerful mutagenic effect, destroying microbial DNA, deactivating and destroying the cells."
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ae6kip | Why do screenshots of screenshots of screenshots of something white sometimes have an off-white/ivory hue about them? | URL_0 Here is an example. It might be that the original was that colour but... I don't know, it's either a thing or it isn't. Thanks | Technology | explainlikeimfive | {
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"I think it is a picture of the screen, not a screenshot. The camera got the white balance off resulting in the off white color."
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ae7t7q | Carbon Capture | I know I have read in various places that technology exists to capture carbon from the air and break it down or reconfigure it in some other way, so if the major culprit of climate change seems to be excess carbon why aren’t we mass producing and utilizing this technology to try and help reverse things? | Technology | explainlikeimfive | {
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"Its expensive. Carbon capture is super useful for industrial processes where they put out tonnes and tonnes of carbon into the air as a waste product. And a bunch of those industries (like steel, cement, oil, etc.) are implementing those technologies. They are doing so due to pressure from carbon taxes and cap and trade programs, so it makes financial sense for them. It is always worth remembering that no one is going to spend money on their business if it doesn’t benefit them (and specifically them) in a fiscal way. For ambient carbon (in the air around us) its just not efficient. Carbon sits at around 400ppm, thats 400 parts per million, or 400 percent of a percent of a percent. Pulling it out of the air is just too hard and you don’t get much out. Its more cost effective to just plant a bunch of trees and let them work passively.",
"> why aren’t we mass producing and utilizing this technology to try and help reverse things? Because to reverse the transformation you have to input as much energy as the transformation gave. So if you burn fuel to make electricity it doesn't make sense to then use the electricity to transform part of the emitted CO2 back into organic matter."
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ae82cw | What are 4km/h bumpers as mentioned in the safety features of cars? | Tried to understand this concept on various sites but still could not get it. Can someone please explain it in a non-technical way? | Technology | explainlikeimfive | {
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"Bumpers are the parts of the car on the far front and back that would first make contact if you run into something. They might be rated for 4 kilometers per hour because there should be no visual damage to the bumper after an impact at that speed or slower."
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aealbw | What is the most viable alternative to fossil fuel and why has it not already replaced conventional fuels? | Technology | explainlikeimfive | {
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"The answer to the first question isn't yet settled for grid-scale power generation. It looks like a combination of solar and wind are the best bets, but nuclear is still in the running. And there's always the possibility that workable fusion becomes a thing. But all of those have open questions: for solar and wind, availability is still unanswered. Probably a combination of distributed generation (the wind is always blowing somewhere) and energy storage (batteries, pumped hydro, compressed air), but it's still evolving. For nuclear, safety and waste management questions still dominate - along with, crucially, financing. A nuclear plant is an enormous capital expense, and the breakeven point is decades out. Fusion continues to be twenty years out, but there's always the possibility that there's a sudden increase in funding and the timetable accelerates. And all that is also part of the answer to the second question: since we haven't settled on a solution, we also haven't rolled it out. But even if we did, the sheer scale of the problem makes it a multi-decadal effort. There are an awful lot of fossil fuel plants still operating, and there's only so fast we can build windmills, solar panels, and nuclear plants. Meanwhile, there's no appetite for dramatically curbing our energy use, so they all need to keep operating until their capacity has been made up for from other sources. When it comes to other fossil fuel uses - vehicles, mostly - it's a similar question. While it certainly seems likely that electric is the future, that's not a guarantee. Hydrogen is still being worked on as a replacement fuel (to be clear, I personally don't think it's a plausibly viable solution, but many people both smarter and better educated in the area than I am think it is). And again, even if we all decided that electric was definitely the way forward (and somehow solved the problem of energy density for airplanes and cost for cargo ships), it would be a multi-decadal effort to replace the entire fleet with electric vehicles. Even the most aggressive car buyers don't typically buy a new car more often than once every three years, and that period can't really start until there's the manufacturing capacity to meet the demand. Meanwhile, the people who buy new cars every three years rely on a secondary market for the car to be sold into. The average age of cars on the road in the U.S. is something like eleven years, IIRC, and the US consumer is (on average) more aggressive in buying new cars than most of the world. In short - we don't actually know what the most viable alternative is, and even if we did, it's a huge undertaking to rip and replace all the deployed infrastructure."
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aed3re | How do people know which clocks are more accurate than others? How/why are atomic clocks more accurate? | Technology | explainlikeimfive | {
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"The more slices you can make in an object the more precisely you can define any group of those pieces. In a mechanical clock we split time into turns of a gear, clicks of a ratchet etc. Then we define a minute to equal a specific number of those pieces. But because those pieces are made by people there can be minute variations from clock to clock. In an atomic clock we measure the vibration of atoms themselves, a very very rapid movement. Since these movements do not vary we can define a second as a specific number of these vibrations. Because there are so many more of them, and they have essentially no variance, we can say that definition is more precise, or accurate."
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aedv6c | air con in cars | Why does running you AC in your car use more fuel | Technology | explainlikeimfive | {
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"text": [
"Because it takes energy to drive a compressor to make the air conditioner work. Energy doesn't come from nowhere, so the fuel consumption is slightly increased.",
"When you look at the engine in your car, you'll commonly see a bunch of pulleys and belts spinning, usually most visibly the last place you want to stick your finger into while the engine's running. All of those pulleys and belts are being driven by the engine, which is powered by fuel. Generally, the more belts and pulleys you add to the engine block for it to spin, the less power you have on hand to drive the wheels. Kind of like if you're carrying a heavy backpack and you were adamant that you needed to walk at a constant 3 mph, if someone added 10 bricks to your backpack you'll be using more energy to keep that pace. You *could* spend the same amount of energy carrying that higher weight at a slower pace, or you can carry the weight at the same pace but use more energy doing so. Your engine's engineers opts for the latter. Same deal with the AC. When you press the button in your dash for A/C to come on, one of the pulley/belts driven by the engine links with the AC Compressor to begin condensing some sort of special gas to make the air flowing into your cabin cooler. Managing this pressure, blowing this air will also cost some more electricity. Because a vast majority of your car's electricity is powered by fuel (see battery/alternator relationships), pressing the AC button is the moment when you add bricks to your backpack. Hope that helps."
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aeedy6 | how we are able to get radio signals from places billions of lightyears away | Technology | explainlikeimfive | {
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"text": [
"First it is coming from an extremely strong source, and second we're using very large 70 meter dishes to gather them and low noise amplifiers cooled with liquid helium in order to detect them.",
"Are you asking what the source of the radio signals are? Because then the answer is likely \"we don't know\". Or are you asking how radio signals can travel so far? In which case there's little to no resistance in space, and as long as they remain unblocked, the radiowaves would keep traveling",
"Radio waves are just low frequency light. As long as they don't run into anything, they'll just keep going and space is mostly empty^^^[Citation ^^^Needed] . The strength of the signal drops with the square of the distance, but there were some pretty strong signal senders a billion years ago, and we have very good radio telescopes."
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aeeen7 | Fiber Optic Cables | Technology | explainlikeimfive | {
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"You and me can see each other's bedroom windows and want to communicate so we invent some rules for how we're going to signal each other. If I display one flag, it means I'm awake, 2 means I'm in the shower, 3 means I'm eating breakfast, and 4 means I've left for the bus stop, meet me there. One day we get walkie talkies but we want to talk in code so our sisters don't know what's up. I pick up the walkie talkie and speak \"four\" into it. You still know what that means even though our communication channel changed. Copper cable transmits bits by varying voltages. Fiber does it by varying intensity of light. It's just signals either way and you can speak with all the same protocols irrespective of the signaling method. Tl;Dr it's just a blinky light",
"Actual fiber optics engineer here. Several of these answers get close, but there are also some errors. Since I'm not sure exactly what you are looking for, let me give you a few facts: * Fiber optic strands are made of pure glass, and the are very thin, like a human hair. They are so thin they can be easily bent, but will break if bent too tightly * The main reason they are used is over copper (like CAT5) or coax (like cable TV cable) is because the losses are very much lower, and fidelity of transmission is much higher. If you put a pulse of light in a fiber optic cable it maintains its level much farther and is distorted much less than if copper or coax are used with electrical signals. We regularly send optical pulses across the Pacific ocean and they come out the other end without error (I am in undersea fiber optics, and we do this every day) * In air, radio frequencies actually travel better than light, that's why you use radio for WiFi, radio and the like. Water vapor (fog), dust, and such make air a very poor medium for transmitting data with light. It works over a short distance, but not for many miles. Also, it isn't trapped in a fiber, so it spreads out and gets weaker, so losses are high. * The speed of propagation (how fast the bits move) in fiber optic strands is 2/3 the speed of light. (OK - ELI > 5, this is because the index of refraction of glass is 1.5, a measure of speed of electromagnetic waves - and light is electromagnetic - and the inverse if 1.5 is 2/3. Read about index of refraction on Wikipedia) * How does the fiber optic keep the light in? The glass fiber isn't the same kind of glass all across its cross-section. Engineers layer the glass in a special way such that light rays that enter the fiber are reflected or bent back toward the middle as they travel down the fiber, so the light gets trapped inside and bounces down to the other end. * \"Translation\" is as follows: On the transmit end there is a light (usually a laser) that encodes electrical data into pulses (the simplest systems just use on and off). The light travels down the fiber. At the receiving end a device - typically a photo-sensitive diode - turns the light back into electrical data. So electrical bits - > laser - > fiber - > diode - > electrical bit. If these didn't answer your question, let me know what in particular you are looking for. Good luck! [Edit: added bullet about translation]",
"Fiber optic cables do not do any of the translation. They only carry the signal. Just like a copper line just carries the signal. For fiber optic cables, the signal is in form of light pulses. The translation occurs at the end of the cable with cables that convert the light pulses to electrical charges, which is what computers use.",
"In very very very very layman's terms, based on my understanding, light goes Bing boing boing boing bong all the way through out the other end.",
"Think of telegraph machine; they don't decode anything they just send/receive signals, the person using the machine decodes the message into meaningful data. The same with fiber optics; the cable itself just transmits a signal and the computer that receives the signal decodes the data.",
"Computers communicate using ones and zeroes. This can also be thought of as \"on\" and \"off\". When computers communicate with fiber optics, they flash light very, very, quickly through a cable. When a flash of light is \"seen\" on the cable, that is a one. If there is no light that is a zero."
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aeeinf | DRM and DRM removal software. How does DRM work and isn’t there removal software that works for all services? | Edit: thank you for all the replies. It makes sense thinking of drm as a description instead of the “product”. Was kind of hoping there’d be one tool to crack them all so I wouldn’t have to buy 3 different softwares. | Technology | explainlikeimfive | {
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"The problem with your question is that it's hard to explain such a large concept in layman's terms... Beyond that, DRM is so large that anything anyone says can likely have someone reply to it with \"you are wrong\" as they provide some edge case... DRM or Digital Rights Management is a term used to cover technology and software that attempts to prevent piracy and the sharing of copyrighted materials. An example of DRM is with a lot of computer games that came out between 1990 and 2012 is that you would buy them and they would contain a key (a series of letters and numbers) that you would be prompted for on installation... This meant that if you say bought a copied disk of the game that you couldn't install the game without the key (except that a key could either be shared and a lot of games reused the key so if one person posted it online it was available to everyone). Another type of DRM within the playstation 1 was that they used specific specialty disks that would basically wobble and this wobble was used to determine whether it was an authentic disk or not, however there are multiple ways to bypass this from installing a modchip (difficult) to actually starting the load process with one disk and quickly swapping disks after it does its security check. So how does DRM work? Depends on the implementation, there are dozens to hundreds of examples of DRM because it's such a broad thing, and this is why if I say something like \"DRM works by checking the authenticity of the files\" could be replied with \"you are wrong\" as some DRM implementations don't check for authenticity... Some will allow for a limited number of installations (like iTunes, at least how iTunes used to) where you can only have say 5 devices connected to a single account and each device has to pair with the server before it can be considered connected... > Is there DRM removal software... Yes. > ... That works for all services Oh, uhm no... Because not all services are the same... The easiest way I can say it is that every medium to large company (this includes things like supercell) that produces digital media probably has developed their own DRM implementation, and not all of those implementations are publically available.. Some of their implementations may be server side... So it's very difficult to truly develop a workaround for many of them... Also not all DRM is purely digital, some is mechanical.",
"DRM is a generic term for any system designed to prevent you from using media without purchasing it. There are many forms it can take and each works completely differently from every other. There's a huge variety and it would be impossible to explain it all. But this does mean that the answer to question 2 is no. They different methods are so different that it is impossible for a single solution to address all of them. Some of them aren't even wholely software.",
"All of the other answers are generally correct and very informative, but I want to describe an edge case that demonstrates how problematic DRM methods can be to work around. The Nintendo GameCube implemented a physical (rather than digital) form of DRM to prevent copying of game discs. Almost all optical disc drives read discs starting at the inside ring and moving outward to the edge. Nintendo designed the GameCube to read discs the opposite way - from the outside edge to the inside hole. This meant that you couldn't put a GC game in a computer disc drive and read the contents, because the computer couldn't recognize the file structure on the disc. Eventually some people were able to hack the GC and connect it to a computer so that they could use the GC to read out the files on the disc - but this still leaves you with a problem. If you take your copied files and burn them onto a normal optical disc using a normal disc burner, it won't work on a GameCube because the GameCube reads discs outside-in but your copy is a standard inside-out disc. At one point there was a kit to replace the entire top of a GameCube with a standard optical disc reader in order to easily play illegally copied games, but unless you were really good with electronics you had decent odds of wrecking your GameCube in the process. It's worth pointing out that this is an example of good DRM. It protects the content but does not affect the normal use of the product. There's no encryption, no nasty spying software (e.g. Sony rootkits), no required always-on internet connection, and not even the inconvenience of having to enter a key code.",
"Simplest version. DRM is a lock. It needs the key to unlock what's inside. That's it! That's all DRM is. A lock. You say \"Great. I have a Skeleton Key that opens any lock it's in.\" That's one of your programs. That's awesome! Except... It only fits one kind of lock. It doesn't fit those little padlocks, or bike locks with that tube kind of key. It definitely doesn't help those military ones that need two keys turned at the same time. And then what about combination locks that don't use a key at all? And those new car keys with a microchip in them? Fingerprint locks? Retina scan locks? Or maybe it's the McDonald's bathroom lock, where someone in another room has to see you on a camera first and then buzz you in. Every one of those needs a different way to get past the different kinds of lock. And DRM is inventing new styles of locks *every single week*",
"If software is a door, DRM is the lock. It only lets those who have a key (customers) in, and keeps everyone else out. However almost any lock can be picked (cracked) with time, effort, and skill. To combat lock pickers, companies will make new locks with mechanisms that no one knows how to bypass yet. Lock complexity can be increased for added security but it can cause problems. A door with a hundred locks will keep anyone without the keys away, but can be a rather unpleasant experience even for key holders. (DRM can negatively impact the software it's used in by impacting performance or reducing compatibility.)",
"The problem is that DRM is a entire class of tool, and there's a large amount of complexity. Let's argue, for a minute, that we're only discussing software encryption systems. Individual encryption DRM tools can differ in: * What they encrypt * What encryption algorithm they use * Where the decryption key comes from * When they decrypt, and how much they decrypt at a time * What conditions they require for decryption key access (for example, TPC module, ARM TrustZone, etc.) Within each of these points are hundreds of little details. As such, there is no 'one-size-fits-all' solution. A counter-example are file archiving tools. The creators of file archive formats ACTIVELY WANT you to be able to get into the file archive, generally; however, most archive managers handle a limited subset. For example, 7-zip handles a huge number of file formats. Even it has limitations though. It can't open .PAK files from Doom, as just one example. DRM is working against you with encryption.",
"DRM tries to make sure that you can do some things with the content (like listen to music, watch a video) but not others (like copying it). This is basically impossible - they're trying to make sure you have access to it but also don't have access to it. Therefor, most DRM employs security by obscurity: They try to hide the content, move it around in memory, and their code is obfuscated (intentionally made super complicated and hard to understand) in order to make it hard for anyone to figure out how it works - because if they did, they could copy the content. Each service usually does it differently, which explains why there isn't a software that works for all. Usually, there is a series of encryption keys involved. The content is encrypted with a key (often the same key for everyone, so they only have to make one version of the huge video file, and can distribute it more easily - this way, they can store a pre-encrypted copy in several locations and send it to you from the nearest one, instead of having to send individual copies to every person). *That* key is then encrypted with a second, per-person key. This second key is only accessible to the DRM software, which decrypts (\"unwraps\") the actual key, uses it to decrypt the video, and tries to keep you from getting access to it. Newer schemes are integrated with the hardware - for example, only your GPU may actually be doing the decryption, making it much harder for you to get the key. The GPU will then also refuse to output the video to a *screen* that isn't certified (doesn't have special keys) so you can't just connect a fake screen and capture it that way. The easiest way to deal with it, usually, is to just ignore the thing altogether and pirate a high-quality, DRM free version of the content. This also has the advantage that it won't randomly refuse to play because your screen, GPU, cable, software, etc. doesn't meet the DRM/certification requirements."
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aefy8t | in online games with the “report player” function (I.E. Fortnite, Overwatch, etc) how do the developers avoid spamming/ griefing? | Technology | explainlikeimfive | {
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"Clarification question: Do you mean how do they decide if a player was spamming/griefing? Or how do they prevent spamming/ griefing of the actual report system? In the first case: lots of systems like that sort users based on how many reports they have, and slowly work down the list, prioritizing users with more reports. In the second case: if a user's reports are often of people that end up not being found to be not guilty of the actions they are reported for, the user that is spamming the report system may be punished."
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aeg27b | How are we able to detect to see Neutron Stars, when Neutrons are electrically neutral and you need something for light to interact with via electromagnetic force in order to see them? | Technology | explainlikeimfive | {
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"Neutron stars, at least, when relatively young, are very, very hot, and are detectable in the infra-red, or even visible light. They can even be spinning so fast they produce strong radio signals that regularly pass over earth, and we detect them as pulsars. But, no, we would not be able to detect old neutron stars, once they have cooled off and their rotation slowed."
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aehbkq | How is electricity divided into different components in an electrical device / sub-grids when required power from each component varies? | Take for example a monitor that takes power from the wall socket of 110V/13A AC (or 220V depending on where you are) but you dim the brightness and have a static image. I imagine the power consumption in this state is much lower than if you have the brightness cranked up to highest and other power consuming features working. By extension, in higher power states (brighter setting), components would be requiring more power compared to lower power states. How does the AC/DC adapter (and other power associated components) work to distribute the required power to said components? Do they step down the voltage? throttle current? is this done by a varying resistor (or some other fancy resistor) If a resistor type is used, wouldn't the resistor heat up, and consume the otherwise unused power? As a result, the monitor as a whole, would still eat the same amount of energy in lower states (less energy used to light the screen, but more used to push current through resistor) and higher states (lower resistance burns less energy unnecessarily to allow more current/voltage to fill higher performance demand) A simpler analogy is this: dimmer switches on lights. If its fully lit, say the light consumes 50 Watts. But when dimmed to as far as it'll go, the light itself consumes 10 Watts. But obviously there's a variable resistor involved, does that resistor burn up 40 Watts into heat? What would be the sense in that? The dimmer+light system still eats 50Watts regardless of the brightness setting used? | Technology | explainlikeimfive | {
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"> If a resistor type is used, wouldn't the resistor heat up, and consume the otherwise unused power? Yes, it does. You can do this with low powered components like small LEDs, but dimming a large light bulb with a variable resistor (potentiometer) would be waste a lot of power. Stepping down the voltage is another way. There are step-transformers which have multiple output voltages, and this is one way you could regulate something like an AC motor. But today, this is usually done with semiconductors. A simple dimmer uses a type of switch called a triac, which only lets current flow for a fraction of the time. [This]( URL_0 ) diagram from Wikipedia shows fairly well how that looks: The shaded area shows the time where the triac closes and current flows. Because it's open part of the time, the total amount of power that flows through the light bulb is reduced. Now this doesn't work with all devices. Things like electric motors and fluorescent bulbs don't like a chopped up current like that. So a better way to achieve the same effect is to use a transistor that switches on and off extremely rapidly, thousands of times per second. The chopped up current is then smoothed by a capacitor, resulting in a clean AC or DC current of your desired voltage. This wastes a lot less power than either step transformers or resistors, and is an integral component of pretty much all power supply units in modern day electronics."
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aeiyyo | Dolby vs. THX | [Derived from this recently posted on r\funny]( URL_0 ) | Technology | explainlikeimfive | {
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"Dolby Laboratories are a company that develop and license audio technologies - especially surround sound standards like 'Atmos' and 'Dolby Digital 5.1' that give content creators, consumer home theater manufacturers, and movie theaters a shared and agreed standard way to playback audio that sounds like it's coming from all around you. In the past they licensed special technologies that got rid of most of the 'hiss' you would hear on old cassette tapes, and 'Dolby Surround' which was a way of sneaking in a third rear-surround channel so it could be heard on conventional Left/Right Stereo speakers, but when you had the right equipment would produce a third rear-channel. There's a lot of complicated and clever maths behind most of their technologies. THX however don't develop any technologies, but instead certify that theaters or certain equipment meets a particular set of criteria they deem suitable for a pleasurable or high fidelity audio experience. Think of the Michelin Guide for fine eating, except companies pay THX for the privilege of being certified. In theaters these standards include ensuring there's no annoying 'reflections' (stuff like echoes) coming off of the surfaces of the theater, and testing all the speakers produce a consistent sound. However they also certify consumer appliances and even screens and projectors. It was started by George Lucas as a way of ensuring that audiences were hearing films like the Empire Strikes Back as close to how he intended as possible. TL;DR - Dolby sell companies methods of encoding and decoding surround sound and other audio technologies; THX sell companies certification that their product or theater is of a standard.",
"Dolby Digital will be selected automatically by an AV receiver which decodes this format - and most receivers will support this. The most common type of Dolby Digital is 5.1 surround sound, but there are some Dolby Digital 2.0 soundtracks for systems with stereo speakers rather than surround sound setups. And some special like Dolby Atmos, what is a 3D object base sound system. Dolby is making its own System. & #x200B; THX certification means that a product meets certain standards defined by [THX]( URL_0 ), who aim to set the highest standards for home theater video and audio equipment. This certification isn't limited to AV receivers, and we can find THX certified products across all types of audio-visual hardware. So they don´t have a own system but rather certify other systems to have a very high quality. & #x200B; You could different them in Software(Dolby) and Hardware(THX)."
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aelmka | Why are two-way radios so short-range and unreliable when longer-range mobile phones are so cheap? | A pair of two-way radios that have a range of perhaps 5km is likely to set you back around £70 ($100), and the signal is usually noisy and poor-quality. A mobile phone, which has to transmit to and receive from the nearest tower (maybe 15km or more) can be bought for £10 including £10 top-up in a phone store, and generally delivers near-crystal-clear audio. How can this be? Why are there no "peer-to-peer mobile phones"? Is it something to do with the size of the receiver on the towers? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Cheap hand-held radios you can buy without a license tend to use public frequencies, which means you're sharing radio waves with all sorts of things. There's also noise from electrical devices which is typically illegal but unenforced. Cellphones use private radio frequencies that have more favorable propagation properties (rather than scattering or absorbing in the atmosphere), and they can use more sophisticated modulation - how the signal is formed, whereas public frequencies might have legal restrictions to typically just AM or FM (it's typically illegal to transmit obscured or encrypted signals on public frequencies, to promote free and open communication). Unlicensed transmitters are also typically legally restricted in output power (so are commercial devices), but I don't know by how much, let alone compared to a cell phone. The more wattage, the further you can be heard. The ability to hear is based on the receptive power of your antenna, measured in gain. Many antenna are omni-directional, and that often makes sense, but that means they're not good at hearing far away. High gain antenna like the old television \"yagi\" style or satellite dishes, are very directional, and practically deaf to perpendicular signals, but they can focus weak signals from far away. The length of a transmitting antenna is a function of the frequency, and you can get away with shorter antenna based on harmonics and some simple math that I'm just not going to get into here. But \"half wave\" and \"quarter wave\" antenna are popular to save on wire and can make use more practical than having a huge bobbing thing whipping you in the face and catching things. Cellphones have very, very tiny antenna because they work on high frequencies, vs. some of these amateur radio setups that have dipole antenna 160 meters long, if you're lucky enough to have the space. When it comes to receiving, any antenna will do, but more is better. This is why the old crystal radio kits work when you use your sink faucet as the antenna. These \"random wire\" antenna are not good for transmitting because they can cause feedback into the radio (ELI5 version) and burn it out. While cellphones are cheap and make a clear signal, they do come with a fair share of compromise. First, the phone is cheap but the service subscription is not. And you don't control the service - they can cut you off at any time, and now you're radio silent. If the service is unreliable, you might not be able to reach anyone, even if the system is operational. And you don't know who is listening or what they're doing with your conversation you are giving up to their network. Civil Band radio shares some of these problems - you don't know who is listening or what they're doing with your transmission. But if the power goes out, you can still talk to people - you're not constrained by the availability of the network. Also, a radio is a one time cost, with no service fees. Additionally, if you become licensed in amateur radio, you can get different equipment that grants your access to better frequencies and transmission modes that will let you talk to anyone in the world over Morse code, digital modes, send pictures and video, use computers and send data and signals that way, or use other modulations and modes that are equal or superior to cell phones, you can communicate with or across satellites, you can bounce signals off layers of the atmosphere and \"skip propagate\" around the world, or even bounce signals off the surface of the moon. There are guys who commonly communicate with Morse code from the Americas to Europe using half a watt of power, which is enough energy to dimly light a flashlight with half dead batteries. I mean, that's no way I would want to talk to my grandma, sure, but on the nerdy coolness factor, that's pretty impressive - that so much can be accomplished with so little. At least give them that."
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aemfe5 | How does a helicopter fly forward, and not just up/down? | Technology | explainlikeimfive | {
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"text": [
"In order to fly forward, a helicopter will tilt slightly forward. Now that it is tilted forward some of the downward thrust will actually push it forward instead of just up.",
"There is a plate attached to the control stick and another plate which connects to each of the rotor blades via connecting rods. When the pilot makes a control input it moves the lower plate which then causes one of the rotors to change its angle of attack as it passes a fixed point in its rotation. For instance as the blades spin the lower plate causes each blade to change angles as it passes the front of the circle. This creates differential lift on the front, rear, or sides of the rotor disk and causes the aircraft to move forward, backward, or laterally.",
"Say for the sake of argument here the rotor is up to speed and is spinning at a certain rate. The amount of downward thrust that generates depends on the angle the blades are at. If they're flat, it doesn't matter how fast they're spinning there'll be no downward thrust. The steeper they are angled, the more of a 'bite' they take out of the air as they go around, and the more air they force downward, and the more thrust they create. You stick your arm out of a car window at speed and you can feel it. Hold it so your hand is flat parallel to the road and it's fine, start tilting it and you can feel the force trying to move your arm up or down. That's because your hand acting on the air that's hitting it, creating downward thrust, making your arm lift. So far so good? This is called 'collective' pitch adjustment. An adjustment to the pitch of the rotors is done collectively - all at the same time. But as you can imagine, all this is good for is lifting you straight up, or lowering you back down. Actually moving anywhere is different, and you'd be right. The magic bit is called 'cyclic' pitch adjustment. If you want to go forward, you have to tilt the helicopter forwards, and the way you do that is increase the lift at the back of the helicopter, compared to the front. That will lift the back end and make you start moving forward. So what you do is use a clever mechanism called a swashplate. This allows you to adjust the blades depending on where they are in the rotation, such that when the rotors are towards the rear of the helicopter, they're pitched more steeply than they are at the front, so the overall lift is greater at the back than at the front. This mechanism works on all the blades, so if you're pushing the stick forward, then as any blade moves to the back of the rotation, it's pitched more heavily than it is at the front, giving more lift at the back, and and tilting the helicopter forwards. This mechanism works in any direction. Pull the stick back and the swashplate will pitch the helicopter blades harder when they're at the front of the rotation than at the back, tilting you backwards. Stick left or stick right, same deal. What this is doing basically is making it so only a certain part of the full spinning rotor gives you more lift than the rest, making you tilt one way. So that's up and down done, tilt forward back left and right. How does it rotate? How do you turn left and right? That's the little rotor at the end of the tail. Because the main rotor is spinning one way, if there was nothing stopping it, the body of the helicopter would want to spin the other way. It isn't going to just sit there nice and still with nothing helping it - it's in mid air. So that tail rotor blasts thrust out to cancel out that rotation. If you balance it nicely, the helicopter will point one way. Increase that thust more than is needed it'll start turning one way. Back it off, and it'll turn the other way. That's basically it."
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aemqzt | Why when you go to the dentist and get x-rays do you wear a lead vest on your chest, but nothing over your head? | Technology | explainlikeimfive | {
"a_id": [
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"X-rays don't do much of any damage to you. hundreds of xrays would do damage, that's why the dentist will go often into a protective room. Its like getting single pin prick on your skin to get a drop of blood for testing. That doesn't really hurt you. but 1000 pin pricks and 1000 drops of blood might kill you. the lead sheet just give a little extra protect from something that really wasn't too damaging. Like how they'll sterilize and area before pricking it. How many times have you gotten a tiny cut and had it NOT get infected. Sterilizing isn't really necessary, but its better then not sterilizing.",
"Because you want the xrays to pass through your teeth. The rest of the body is protected from unnecessary radiation"
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