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eoq6fr | - What exactly is Nuclear Power? | ELI5 Where does it come from? How is it made? What is it used for? (I'm in Ontario and always thought my electricity came from water plants, hydro electricity) | Technology | explainlikeimfive | {
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"Nuclear power is power produced by splitting atoms. Atoms of the heavy element Uranium, in particular. This process creates a lot of heat, which is used to boil water into steam, which powers a traditional electric power generator. The energy comes from E=mC^2 , when the Uranium splits the pieces weigh less than the original and the bonding energy that held the big atom together is converted directly to heat.",
"In a simple sense, take some somewhat unstable large nuclei, such as uranium, shoot some neutrons at it to form a nuclei that splits into smaller parts rapidly. That process releases a lot of heat and releases neutrons to carry on a chain reaction. Control the rate of the reaction so your facility doesn't explode, and use the heat released to boil water. Use that steam to drive a turbine powering a generator."
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eowr9c | Why is location data tracked by apps valuable to companies? Who buys this data and what do they do with it? Should we be worried about it? | Technology | explainlikeimfive | {
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"Imagine you live on Safe Street. After work you walk through the backyard over to Danger Street to buy potato boomers for your elderly neighbor that are only at that particular bodega but hey you’re just that kind of person. One day you wake up and your automobile insurance has increased. The ALGORITHM determined that drivers who spend x amount of time on Danger street are at a higher risk. “But I wasn’t driving?!” Well hopefully the engineers accounted for that. Then you notice your health insurance has increased - too many potato boomers. These are just a couple instances but yeah your data is inert but peoples (read: GOVERNMENT and CORPORATIONS) interpretations of that data can be very dangerous.",
"As an individual, it’s not that valuable. I doubt that any company cares specifically where I went today. But as part of a large database, consumer trends can be ascertained. For example, lots of companies are interested in a demographic breakdown of who shopped at their stores today, where they came from, how long they stayed.",
"You should probably check out the documentary 'The Great Hack', it explores how your data is collected and can be used against you by companies like FaceBook e.g. during democratic elections such as the whole Russia-Trump debacle. Obviously this goes beyond location tracking, but it is an example of how your data is compounded and is used to influence your decision-making which in the long term is pretty scary stuff.",
"THe problem is its invasive. A company can learn things about you before you know them about yourself and its both uncomfortable, and uneasy knowing that this info is used to take advantage of your weaknesses. For example, Target figured out a way to determine if a shopper was pregnant, often before the shopper wanted people to know. Target would give these people coupons for newborn stuff before the people told anyone they were carrying, and it freaked them out. This deterred people from Target, so they upgraded their tactics and instead and sent people the same coupons, they just added irrelevant coupons to make it coincidental. They were able to advertise to people based on information they weren't expected to know. You might think your routines aren't extremely defined and predictable, but big data and tracking info can be used to predict your behaviors, shopping weaknesses, and needs before you even know they exist. There are definitely benefits, but having people knowing this about you who don't have your best interest at heart can be worrisome.",
"Companies want to know their customers. They pay money so that they know the habits of their customers which includes where they are to best advertise to them stuff that they think they will want to buy based off that information. Maybe harmless with companies, but very bad if that information gets in the wrong hands via a leak or data breach."
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eoz7hp | why do space shuttles take off vertically instead of on a runway like an airplane? | Technology | explainlikeimfive | {
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"If you're asking why, as a new and improved shuttle, we don't do horizontal takeoff... Well, we're considering it. It presents several challenges that vertical takeoff does not. For one, rocket engines are really good at providing a *lot* of force for not much time. They are also most efficient at high speeds. That means that they're most efficient when the rocket can get out of atmosphere as fast as possible. Now, you could use a jet engine to work around this and this is currently being looked into but it presents a whole different slew of engineering issues that we are only just beginning to be able to overcome. Horizontal takeoff craft would potentially require a lot more wing than the old shuttle, and so that makes them harder to use - especially with rockets which struggle fighting drag. Horizontal takeoff craft also have issues with low specific impulse from atmosphere - rocket engines lose efficiency in different thicknesses of atmosphere *on top of* the aforementioned efficiency issues. Again, jet engines.",
"The space shuttle specifically was terrible at flying. At best it could do a sort of powered glide to landing. I don't know specific numbers, but I do not believe that it could generate enough lift to get off of the ground by itself. The other consideration is fuel usage. Notice how the shuttle's were attached to huge boosters? Without those, there wouldn't be enough thrust for the shuttle to reach orbit. The shuttles engines were too weak and the shuttle wasn't able to carry enough fuel.",
"Basically, to reduce the amount of time spent in the atmosphere. The goal of a space launcher is to get its payload in orbit ( > 100km to keep it simple) and at orbital speed ( > 8km/s). Those are two very energy-hungry tasks. On top of that, getting at orbital height requires to go through the atmosphere (which creates drag and is another energy sink), and as long as you're not in orbit, you're fighting gravity. So you want to reduce that, but it requires going as fast as possible through the atmosphere. Vertical take off is best for that."
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ep33z9 | How is footage recorded onto VHS? | Technology | explainlikeimfive | {
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"VHS isn't film. There is no picture on a strip of VHS. It's a magnetic tape that gets read and converted into a signal to create audio and video data. The pattern of the magnetic particles in the tape can be changed, the Record option uses magnets to change the pattern of the magnetic stuff. Tapes with copy protection actually just use a little tab that interacts with a switch (if the tab is present you can record, no tab is safe) but this doesn't change the *tape*, it just changes whether the VCR is allowed to engage the record head or not.",
"Technology Connections on Youtube explains this. He also has a lot of other videos related to VHS and analog television. [The Impossible Feat inside Your VCR ]( URL_0 )",
"I don't think there's really any ELI5 way to explain how the actual signal that gets recorded onto the tape gets made, as analogue color video signals are crazy complicated. However, the way the signal gets onto the tape is pretty intuitive. The tape itself is made of what is essentially plastic with a bunch of tiny magnets embedded into it. When the tape is recorded, each of these tiny magnets is magnetized to a varying degree, and this changing magnetic field can be read as a varying electric current when the tape is pulled past a playback head. One important thing to note is that there is a lower limit to the size of an area you can magnetize on the tape, which is limited by the size of the magnetic particles, as well as the recording head. This means that in order to record more information, you need to move your heads past the tape faster, so that they cover more area in the same amount of time. Inside the recorder, there is a drum mounted at an angle. This drum spins rapidly, as the tape is dragged around it. The drum has at least 2 heads on it, on opposite sides. This means that each head essentially draws a diagonal stripe on the tape, each picking up where the other left off. The reason for the spinning drum is that it allows you to have a very fast relative speed between the head and the tape without having to move the tape very quickly. This allows the same amount of video to be recorded on much, much less tape. Early attempts to record video on tape failed largely because they just needed too much damn tape. If the tape already has a signal on it, (or actually, whenever you're recording), the tape passes by a demagnetizer before being recorded. There are a few different ways to demagnetize something, but pretty much all tape recorders rely on an electromagnet that changes polarity very rapidly. This randomizes the magnetic fields on the tape, wiping out any trace of the old video signal that could interfere with the new one. Note that some VHS machines have more sophisticated drums with 6 or more heads. These do almost nothing for regular playback and recording, but they enable better fast-forward and slow-motion playback. The reason they're necessary is because the tape's motion slightly changes the angle of the stripes the heads draw. If you try to speed up or slow down the tape, the stripes will no longer align all the way across, which is why many players have static over half or more of the screen when fast-forwarding. Multi-head machines switch to a head that is better aligned when one starts to come out of alignment, leading to more, smaller static bands. (Or, on really well-engineered machines, almost no distortion at all.)",
"Real ELI5 answer here: A VHS tape is literally like an Etch-a-sketch. It records information using magnets. When you erase or record over a part of a tape you're just shaking all the magnetic bits so they don't resemble what they used to anymore.",
"Relevant to this discussion: in 1987, toy-maker Fisher-Price released a black & white video camera that used standard audio cassettes to record and playback video and audio. URL_0",
"Basically, tricking the vhs machine to think there is more tape. Instead of recording the video information in a straight line at slow speeds like audio tape, video tape requires high speed (and here's the magic) a slanted recording path. The heads are at an angle to the physical tape travel direction so you can fit more data onto the same tape. To re-record the tape, there are separate erase heads that remove the previous data from the tape.",
"You know how you touch a paper clip to a magnet, and then the paper clip stays magnetic for a while, sticking to other paper clips? That's the basics of it. Metal can \"remember\" a magnetic field, it becomes magnetized. It can also be de-magnetized in a similar way. This is the essence of all forms of magnetic memory, in audio tapes, VHS, floppy drives and even hard drives. It's easier to first understand how audio tapes work. An audio tape passes over an electro-magnet. The tape contains metal dust and can \"remember\" how strong the magnetic field was when it passed over the tape, a bit like you would draw onto a piece of paper with a pen. Except here, the pen is the electro magnet, the paper is the tape, and the ink is the magnetic field. This field changes in accordance with the sound being recorded, much like you would press harder on the pen to draw a thicker line and press lighter to draw a thinner line. When the tape is played back, the moving tape creates a tiny magnetic field which is turned into sound by the same electro-magnet. The changes in the magnetic field are like the vibrations that create sound. A VHS is just a very complicated version of the audio tape. Instead of just sound, it also stores images. This means that the varying magnetic fields represent the varying brightness levels that are used to display the picture line by line, in addition to the sound. I won't go into the mechanics of the slanted spinning drum, because it's quite complicated, but in the end, it's a very similar magnetic tape that can be read and written to by electro-magnets.",
"Helical scanning is used otherwise the tape would have had to travel through the machine at a silly speed ..... instead of the tape head being fixed like an audio cassette and the tape passing over leaving a long continuous 'track' the record (and play) heads are on a spinning drum set at a diagonal angle so the 'track' is actually thousands of diagonal stripes from top to bottom on the tape. It is only by doing this that the cassette was made a manageable size."
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ep4ji2 | Why is it still so difficult for many countries to produce nuclear weapons, even though the technology has been around for 80 years? | Technology | explainlikeimfive | {
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"It's not difficult for developed countries. If Germany wanted to develop nukes, they can do it without much of problems, they have the money, they have scientists, they have the technological-industrial base. The only issues are political and legal ones. It's difficult for a 3rd world poor country, because they don't have the money, they don't have the scientists, don't have the industrial base, and they are not allowed to do it, so they have do it in secret, making everything even more expensive.",
"Contrary to common beleaves the design of a nuclear weapon is not complex or secret at all. But there is two components in the design that is hard to get. You need weapons grade uranium and precision detonators. And these components can only be used to build nuclear bombs and is therefore very well restricted. There is only a few places in the world with the knowledge, skills and tools to make these economically. And if you try ordering from them they will report you. You may have heard about countries trying to make their own weapons grade uranium. This too is not a very complicated process as the design of the centrifuges is pretty basic. However they do require very high precision bearings that can take extreme speeds and temperatures along with very accurate stainless components. None of these components is something that is needed for anything except specialty research equipment and uranium centrifuges. And it is again something that only a handfull of companies in the world are able to manufacture economically. And they all know exactly what these components can be used for. And to make a uranium centrifuge that can manufacture material for a single bomb every decade you need a significant amount of the world supply of these components. In other words people are going to notice if you start your own nuclear weapons program.",
"I think a lot of it is not having the actual nuclear materials to build the weapon you can google the basic idea of a nuclear weapon, its getting the materials is the issue"
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ep5nqp | Crime shows always say “they hung up before we could trace the call”. What goes into tracing a call and how long does it actually take? | Technology | explainlikeimfive | {
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"It's 100% Hollywood bullshit. It might have been true decades ago when phone calls were connected manually, but not since the electronic switches that we have since the 1970s.",
"This is a holdover from how telephones worked before the 1970s. Nowadays, it's all electronic, and assuming the [caller ID isn't being spoofed]( URL_1 ), it's pretty easy to obtain this info. Prior to the late 1970s, telephone networks didn't use computers and electronic systems. They used [electrically powered mechanical switches]( URL_0 ) that were stacked together in arrays that filled entire buildings, and would physically connect different cables together to make a call go through. Several of these switches were required (in larger cities) to complete a call. In fact, this old mechanical switching system is what dictated how phone numbers were formatted, and assigned. The numbers you dialed would literally tell a switch which central office you wanted to reach, and then tell it how many times to step through its gears, to pass your call to the next switch in a different part of the network, and eventually, to your called person's phone line. In this era, tracing a call *literally* involved a person (or several people) in the telephone central office working through the series of switches to see where a call came from. They would have to **trace** the path the call took... from the called phone line, back down to each switch that contacted it from one part of the network to the next, and on to the originating phone line. This is what took so much time. And, if the caller hung up before the trace was completed, then the effort was wasted... the call would end and all the electromechanical switches would snap back to their standby positions, waiting to be used in the next call. & #x200B; Edit: [Here's a video of these old phone switches in action.]( URL_2 )"
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ep5ule | How do companies know their online data has been stolen? | Technology | explainlikeimfive | {
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"It depends on what was stolen and how it was done. In some cases it's as simple as somebody noticing some fishy logs, investigating what they see in the logs, seeing server and network activity that's not normal, tracking that abnormal activity to build out a picture of what happened. You don't need to see a message saying \"Hey I broke into your database and ex-filtrated all the account information\", but rather you may see a log that shows \"Admin logged in at 2:37 am from X.X.X.X (IP address)\", then checking other logs (time cards or some other employee tracking system) to see none of the admins were working at 2:37 am, then looking that IP up and it came from a country on the other side of the world. From there you follow the session ID of that login and you can find exactly what they did (such as \"SELECT * FROM customer_db), before seeing a large amount of network traffic going from your DB server back to the IP above (showing they downloaded a large amount of data). At that point it's pretty likely that they downloaded your customer database and now have all that info, so you can formulate a public statement, investigate how they got access, implement security fixes, etc.",
"Hackers won't leave a message like 'we have stolen all your data!' So how do companies know that they really aquired x amount of data?",
"Often they do not. Sometimes it is discovered later through review of system logs. Other times it becomes known when the data appears for sale. In these cases the veracity of the data is often called into question as well, because as you said there is no good way for a company to know."
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ep6wta | Why do gifs take longer to load than most videos? | It seems whenever I come across a gif, it takes forever to load while I have no problem loading much longer, higher-quality videos | Technology | explainlikeimfive | {
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"Because they don't stream, you have to load the whole thing before you see any part of it. Also, if you are talking about animated gifs, they are typically bigger than an equivalent MPEG. This is because they use a simply form of compression, and can only compress each frame individually. MPEG allows you to compress across frames, if two frames are almost the same, only the differences have to be transmitted with the second frame.",
"Gif files are not a streaming format. They can’t buffer and then start playing when there are a few seconds worth of the file loaded. They have to completely load before they start playing.",
"Because GIF is a terrible antiquated format that needs to die but hasn't because it has widespread compatibility. Put simply, they have terrible compression. Modern day video encoding does a lot of work to compress whats there, how it works is a massive rabbit hole, just know that it works in large part by deriving frames by recording how each frame is different to the other frames around it, instead of storing each frame individually as an image. GIF doesn't do this, each frame in a GIF animation is there in its entirety as a static GIF format image. Very inefficient way to do video. GIF is also just not very efficient at compressing still images either, this standard was last updated in 1989, so not a big surprise that its fallen behind here especially compared to online video which is in a constant arms race for new codecs. It also handles time very weirdly. For video content you expect a frame rate, every 0.333 seconds a new frame appears so you get 30 in a second. GIF doesn't work this way, it works by having a hard coded time delay between each frame. Which does make it one of the few formats that supports a variable 'frame rate' I guess, its just inefficient and very indicative how this format was really not intended as a video format."
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ep9y5d | why it’s hard to make an existing game for a different OS | My favourite mobile game is currently only available for iOS and people have been asking why the android version is taking so long if the game already exists. Thanks for taking the time to help me with this! | Technology | explainlikeimfive | {
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"Different operating systems have different ways for the software to interact with them, think of it like 'features' you can use while writing code. So even if your using the same programming language you will have to do things differently and that will require rewriting/rethinking your code. This is true for operating systems in general, my experience (light experience) with android studio was that this goes double for mobile development.",
"The various calls you need to make to access phone resources are different. Often times, the entire structure of how you organize and communicate data depends on making sure your data structures line up with what the platform expect and the function calls to communicate to it. When you want to take that code and port it to another platform, all that stuff has to be rewritten. Sometimes it has to be completely redesigned. So while you may be able to reuse the assets and game logic, the sizeable chunk that allows the user to interact with the game may need a substantial amount of effort. Game development is difficult and the market is highly competitive. A lot of studios plan for the development of their game, making sure their developers are working on adding more incentives to keep players playing and investing in whatever cash shop they offer. Taking a group of developers off that (and risking the game growing stale) and putting them on porting is a huge risk in that it may take a long time with no payout until the port is complete. Many studios may simply decide not to take that risk.",
"really ELI5 but: & #x200B; The processor for iPhones uses one language, phones with Android use another. So like how if you typed something in English and showed it to a Russian, and vice versa, you guys would not understand each other? & #x200B; Same stuff with phones, if you took the code written for iOS and tried to just copy and paste it, it would not run on Android. & #x200B; Also take into consideration the fact that there are few iPhone models compared to the vast selection of Android phones available, all with varying levels of processing power, screen sizes, etc. So the developers of that app would have to figure out a way to make a really good \"one size fits all\" type app, or actually try to test run it on different phone models. & #x200B; Hope this helped and if I get downvoted to hell, oh well."
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epa1ms | Why do tech companies have greater freedom of contract when compared to other companies? | When it comes to tech companies, it seems you can put almost anything in the terms of use and privacy policy. When it comes to other companies (such as banks and insurance companies) there are certain rights they cannot have you waive. Why does that not exist with tech companies? | Technology | explainlikeimfive | {
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"You're comparing two things you shouldn't be comparing. Banking, insurance, and other financial institutions specifically have lots and lots of government regulations placed on how they conduct business, what they must disclose, and how they operate. Tons of regulations. Few industries compare to how regulated financial institutions are (although many say they aren't regulated enough!), as for the most part, most industries have fairly lax legal regulations in how they operate. Other highly regulated industries, outside of banking/finance, are things like oil and gas, air travel, and pharmaceuticals. Not a shitty iphone game or a note taking app."
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epb8gm | How come telescopes can see galaxies impossible distances away but they can't get razor sharp images of stuff on planets in our own solar system? | Technology | explainlikeimfive | {
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"Galaxies are big. Really big. The Milky Way is ~100000 light years across. That's ~1x10^18 kms. The earth is 12000 kms across. To put it in scale, that's roughly like comparing the size of an atom to the size of the earth."
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epi9kr | How does reverse image search work? | Technology | explainlikeimfive | {
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"Think of an image as a table of colours. For example, this is how the flag of Japan would be represented: 🇯🇵 White white white White red white White white white Now, count how many times each colour occurs in the table. Here, it would be: White = 8 Red = 1 Assume you have a database of millions of images for which you’ve counted the colours like this already. When someone uploads a picture of the flag of Japan, you search your colour counts database and find which other images have 8 whites and 1 red. And these are the “results” you return.",
"When you choose an image to reverse-search, there are a few different algorithms that happen behind the scenes. The results you are shown are generated using one or more of these algorithms. One algorithm, called scale-invariant feature transform, does some calculations to identify a whole bunch of mathematical \"features\" of the image that it can quantify, then those features get compared against the features of known images that it has a database of. Another method is done putting the entire image through a calculation that generates a unique id number (a fingerprint). The system then does a simple lookup for this id and returns any matches. The difference between these two methods is that the first can identify *similar* images while the second can only identify *exact matches*. Beyond these methods there are a whole slew of machine-learning algorithms that are a bit too complex for an EIL5, but they basically rely on \"training\" a computer vision program to categorize stuff in the image, (ie a dog, a tree, a banana, a scale) then search those identifiers (along with other features of the image, like prominent colors) against a database of known images."
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epifad | why does slow motion video need a specific setting? | Technology | explainlikeimfive | {
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"Video is made of of a bunch of photos played back typically at ~24 per second (24fps). When you're talking a slo-mo video it's recording 120-240+ fps. If you were to stretch out a regular 24fps video to be slo-mo it would be very choppy.",
"Let's say you have a 1-second video that was recorded at 30 frames/sec. That means your video consists of 30 still pictures. You can play it back slower, but that'll make it choppier and not reveal any more detailed motion. You still won't see what is happening *between* those 30 pictures. You are just looking at each picture for longer. So to capture more motion detail, you'll need to take more pictures per second. In other words, record at a higher frame rate. That's what the slow-motion mode on your camera does. (Side note: Motion-interpolation algorithms can *guess* what goes on between frames to increase the frame rate.)"
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epowoa | How does electricity get stored/saved? | How does electricity get stored/saved. I understand that it's supposedly runs around in a circuit untill it is released where needed. But is it the same on a large scale? I completely don't understand it | Technology | explainlikeimfive | {
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"On a larger scale it's not. Most power is generated at power plants at the same rate (ish) that is being used. Now in the cases where it is, like with water reservoirs, the turbines in normal dams take energy from the water flowing through them. Since at the power plants we know how much energy is being used and how much is being produced, whenever there is extra it would be diverted to a pump that would pump water back up to the reservoir so it can be used later, instead of reducing the amount produced. This is useful in the cases of renewable energy as you can't really make the sun dimmer at will, and if that power is going to be produced anyway it might as well be saved for later",
"Funny enough, very little energy is actually stored on a large scale - power grids are \"on demand\" with power being generated as it is needed to fulfill draw - power draw goes up, power plants generate more power. There are a few different ways to store power, but they are expensive and/or not particularly efficient. Batteries are the most common and some grids are building very large banks of batteries to store variable, non-on-demand power (like solar) but it is somewhat uncommon due to the cost. Similarly, some grids use the excess power to do work like pumping water up to a container to \"store\" energy; when new electricity is needed, the water is allowed to flow back down past turbines that produce electricity. This, sadly, is _incredibly_ inefficient and only viable when you have extra power that you just can't utilize at all."
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epperb | how does a thermal camera know the temperature of something far away without actually touching the object? | Technology | explainlikeimfive | {
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"Thermal cameras detect temperature by recognizing and capturing different levels of infrared light. This light is invisible to the naked eye, but can be felt as heat if the intensity is high enough. All objects emit some kind of infrared radiation, and it’s one of the ways that heat is transferred. If you hold your hand over some hot coals on the grill, those coals are emitting a ton of infrared radiation, and the heat is transferring to your hand. Furthermore, only about half of the sun’s energy is given off as visible light—the rest is a mix of ultravoilet and infrared light. The hotter an object is, the more infrared radiation it produces. Thermal cameras can see this radiation and convert it to an image that we can then see with our eyes, much like how a night vision camera can capture invisible infrared light and convert it to an image that our eyes can see.",
"It's due to something called \"black body radiation\" Every object emits light based on its temperature. If you've ever seen a hot stove element turn red then you've seen this is real life. The key is the colour of the light emitted is based of the temperature of that object. The colour of the light is the same as the wavelength of light, except that visible light is only a tiny tiny section of possible wavelengths of light. So only really hot objects produce light that you can see with your eyes. A camera can be designed to sensitive to light outside of the visible spectrum. Basically you can design a camera too see \"colours\" that humans can't see, or in other words a camera can measure the wavelength of light outside of the visible spectrum. From the wavelength of light being produced from the object, you can then calculate it's temperature. Thermal cameras are mainly design to be sensitive to light in the infrared spectrum."
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epsenc | - Do nuclear weapons expire? | Technology | explainlikeimfive | {
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"feljdl5",
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"text": [
"Not just do the cores themselves degrade over time, the actual machinery in a nuclear missile will degrade rather quickly over time. The missiles also use particular types of fuel that is highly corrosive, so they can't be kept fueled all the time. Basically, the whole process around a single nuclear missile, its silo and all the support equipment is very sensitive to degradation over time. It's extremely expensive to keep these missiles in a ready-to-launch situation.",
"Yes, and quite fast. Making a nuclear bomb is pretty hard actually. It took the best scientists quite a few years to take care of each step. And each step is one way that nukes expire. Let's look at them one by one. Most nuclear weapons today are made with Plutonium-239 because it's cheaper to get than Uranium-235. They also require a \"spark\" - a neutron emitter. It is required that they be in their pure form, without pollutants that might inhibit a nuclear reaction by absorbing neutrons or something. If the materials degrade, you might just get a fizz instead of a nuclear blast. Current nuke designs are top secret, but the early generations worked as implosion devices that compress plutonium-239 evenly (which is extremely hard to achieve) using very carefully crafted explosives. Explosives as chemicals expire over time, losing some of its standard properties, making it more likely that in the event of the detonation, the implosion wouldn't be even, and would cause the Plutonium to just stream out as a hot jet of nasty poison, rather than start a chain fission reaction. The electronics that trigger the detonation are also subject to degradation. I've read in some books (don't remember which ones really, I like this topic), that upon inspection of the nuclear warheads in the US arsenal just a couple of decades after manufacture, most were found to be in such a bad shape, that they weren't likely to work at all. I'm sure that in the USSR things weren't better. If you disregard their potential to eradicate human life, or at least cause great suffering, nuclear weapons are fascinating pieces of technology. Even the first ones ever made would still be considered a marvel of science and engineering by anyone who has never seen a schematic of one before. They are precise systems, engineered to near perfection, and even that guarantees the fission of just a tiny part of its nuclear fuel in a detonation. Anything short of this perfection, and it will just not work.",
"Yes, eventually. The source material has a half life and over time it will slowly decay. Once this has happened to a large enough amount it will be longer be viable as a nuclear weapons."
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epwv2b | How can computer security people determine whether election software has been tampered with or not? | Technology | explainlikeimfive | {
"a_id": [
"fem9kfi",
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"text": [
"At its most simple, you can compare what are called Hashes. A Hash is essentially a giant number or hexcode that is the result of running a block of information, in this case computer code, through a specialized mathematical equation. Based on whats there, it spits out the hash. If you then take that block of information, change 1 Bit (a Bit being a technical term for the smallest unit of information in Binary), run it through the hashing equation again and it will put out an entirely different hash. So if you know the hash for the legitimate software and you suspect code has been injected into or altered on the suspect system, you can take its code, run it through the hashing equation and compare the results. It wont tell you if its been hacked or anything, that would require proper investigation. just that these two things are different.",
"They can't. But since this /r has word volume requirements, I'll elaborate that there is no standard way for anyone to verify your electronic vote. The software is proprietary, so it's not possible to audit the code security. For all we know, your vote is transmitted to Russia, then converted to whatever Putin desires, and transmitted back. We all should petition our Congress critters to fix this."
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epwyvz | Why the recommendation is to store vinyl records on their side to prevent warping, as opposed to flat. | That logic has always seemed backwards in my head, but it must work or people wouldn't still do it. | Technology | explainlikeimfive | {
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"The vinyl is usually slightly thicker in the center than on the outside partially because of the label so the more you stack them up, the less support the ones higher up have on the outsides, so they will eventually sag down like a bowl especially if they get too warm. The real cause of warping is having them stored on a shelf but at an angle It's also causing a lot of pressure on the bottom records which is bad for the grooves."
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epzgyk | What is a LAN party? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"In the old days of tech when you wanted to play multi-player games with friends you would connect your computers together with eithernet cables to do so, occasionally 10s or even hundreds of people would get together forming a LAN party (LAN stands for local area network but the way)",
"In 1995 several people would take their computers to one place, connect them up with coax network cards and play multiplayer games or share files.",
"Instead of working/gaming remotely over the internet, you can put a bunch of computers in the same room and connect them to a Local Area Network (LAN) and enjoy a smoother experience with higher transfer speeds. It allows for IRL human interaction while doing computer stuff."
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eq0ylz | - How do face masks keep out germs? | I see people on the subway with surgical type face masks on but I don’t get how they work. Do they filter out germs? I would think air could still get in through the sides, in most cases there is a gap where air could get in. What am I missing? | Technology | explainlikeimfive | {
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"I was under the impression people wearing face masks in public were typically a courtesy to keep their own germs from spreading to others. When you cough, you spit a little. That spit has germs in it that get on your hands, your clothes, and things that you touch. If you’re wearing a mask and you cough, the mask catches the spit, and you don’t spread as many germs around.",
"It's more to keep their germs from spreading to others Think of it like this. If everybody with a cold keeps 90 percent of their cold germs to themselves, then 90 percent of the cold germs that normally would be infecting others are... well... not infecting others.",
"By physically keeping out germs. Many illnesses aren't airborne. The virus or bacteria are spread in droplets of fluid. eg, when you sneeze, but also just when breathing in general. While the standard surgical mask is useless as a filter, it does limit your exposure to droplet borne pathogens (provided you also practise decent hand sanitization etc). So in hospitals, they're part of the required PPE if someone has the flu since that illness is a droplet hazard (you also ideally want something that covers your eyes). As others have mentioned, they're also good for limiting *others* exposure. The mask is pretty effective at limiting your ability to contaminate the environment around you when you're ill. Other illnesses however are airborne (tb for example), and proper PPE for stuff like that includes actual fitted respirators. There are disposable options for those as well. They look like [this]( URL_0 ) and are held much much more firmly to your face (you also need to be careful about facial hair etc)."
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eq6pup | Why can fnger print scanners and such correctly scan my fingerprint no matter how long ago it was since they copied it but my phone fingerprint scanner struggles if theres a slight bit of dust on my fingers | Technology | explainlikeimfive | {
"a_id": [
"feo9oa2"
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"text": [
"The grooves on your fingers remain the same over time, they don't change their positions, so no matter when you first had your finger print entered it will still always work, however dust, ink and other substance can make it look like the grooves stop in certain places and this can fool the system - URL_0"
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eq7wh0 | Why did FTP replace other file transfer methods? What did it do better than ZMODEM, Kermit, and the like? | Technology | explainlikeimfive | {
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"You got the timeline wrong, FTP is from 1971, zmodem is from 1986 and kermit is from 1981. It's not that FTP replaced anything, FTP has always been the dominating thing and other protocols came and went.",
"You're mixing up technologies. Zmodem, Kermit, etc are meant for use over a serial cable, dialup modem or something similar - bytes go in one side and come out the other side, but you have the line to yourself and there's no sharing. These transfers tie up the line for the duration of their execution unless outright aborted. FTP is for use on the Internet or other IPv4 (or IPv6 I support) networks. These allow many users to share a connection and the speeds will adapt to what's available. Still, mentioned zmodem brings back memories of dialup BBS's.",
"FTP is a UNIX command that predates the dial-up modem file transfer protocols. The transfer protocols we used when we were all using DOS/Windows 3.1 and dial-up modems were created for dial-up modem connections and the related software, over copper telephone lines. (If you are old enough, you remember all the connection problems before Cable modems/DSL modems/Fiber optics we have now.) Data transfer over the phone lines was very problematic; errors caused by old and aging wiring created symptoms like bad connections, failed connections, multiple re-tries, slow transfers, random disconnects etc. There needed to be a way technology that could correct for those serious data transfer errors when transferring data over bad transmission lines, so the modem protocols were established.",
"Availability. It was everywhere. Even Windows was shipped with a simple FTP client. Also other users correctly note what \\*modem and kermit are designed for a serial, p-t-p links.",
"FTP runs on top of TCP/IP, the Internet protocols. Kermit and ZMODEM were their own thing, all the way down to the hardware. You can do both on the same system at the same time, but not over the same wires. The FTP connection would use something an Internet connection has been established on, and Kermit or ZMODEM would run over something like a serial port, without any Internet connection."
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eq8q1d | How do storage containers keep cookies crisp when they have air inside them? | How do containers like Tupperware stop cookies and crackers going soft since there's still air inside the containers with the food? | Technology | explainlikeimfive | {
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"They go soft because they are absorbing moisture from the air. When out in the open, there's an infinite (for all intents and purposes) amount of moisture for them to absorb, but when closed in a container, they can only absorb the moisture in the small amount of air in the container with them. At some point, the moisture level in the air reaches an equilibrium with the cookies/crackers and they don't absorb any more. The same thing happens with things that go stale, like bread, but in the opposite direction. They want to dry out, but when in a closed container the air inside can only hold so much moisture. The rest is forced to stay in the bread so it stays soft.",
"In addition to it being dry, most packaging tries to pump in special air that is nothing but Nitrogen, with no oxygen. Doing that tends to keep most of the microscopic organisms that cause decay from being able to thrive.",
"I reas that bags of chips don't contain oxygen, but instead contain nitrogen. This preserves the chips. I am unsure if cookies are similarly treated."
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eq9y9a | How do scopes and sights on guns work? Wouldn’t you be firing higher than the barrel, making you inaccurate? | Technology | explainlikeimfive | {
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"Yes, but at the same time, bullets fly in an arc. The scope is actually slightly pointed down in relation to the barrel, so it crosses the line of the bullet at two points. These are called the \"zero\" points. These are where the scope shows exactly where the bullet will hit, disregarding wind and other extraneous variables. The top dial* on a scope allows the shooter to adjust it for the range to the target, maintaining high accuracy. Most rifle ironsights also allow adjustment, at least with a tool, for the same purpose. I'm actually not sure if it is the top dial, but one of them. :S"
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eqanca | How do those water jugs with hot and cold dispensers heat and cool the water SO fast? | Technology | explainlikeimfive | {
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"They actually dont. They heat/cool a reservoir of water that you pull from. They can 'run out' of hot or cold water if there is a line.",
"They use Peltier elements for both cooling and heating. They are also used in mini-fridges. [ URL_0 ]( URL_1 )"
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eqdl4x | why is airplane mode necessary while flying in a plane | Technology | explainlikeimfive | {
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"In the past the fear was that your phones radio signals could interfere with the aircrafts navigation, communication and other electrical systems. Nowadays not so much because we have learned how to prevent our instruments from being effected by the electrical lines of flux by surrounding them with, preferably, a thin layer of Soft Iron. However, the risk is still there thus why the flight crew will still ask you set your phone on airplane mode. I’m going to school to get my A & P (license to work on commercial aircraft in the U.S) and this was one of the first questions i asked at school, haha.",
"It isn't. If it were actually dangerous they'd treat phones like (gasp!) shampoo bottles."
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eqdlvh | How do television or radio stations know how many people are tuning into them? | Technology | explainlikeimfive | {
"a_id": [
"fepxnah"
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"text": [
"[Nielsen tv ratings]( URL_0 ) they have a sample of consumers who have a device installed that tracks what channels the sample is watching, how long it’s being watched and extrapolate it to the rest of the consumer population, if 2000 people in a certain area are watching something at a certain time they can say that based on that sample that other people in the area are watching the same thing if say 1200 people in the sample are watching the same thing"
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eqgf6o | mvvm concept in software design - model view view model? | I literally studied computer science and don't understand this. I'm so frustrated. | Technology | explainlikeimfive | {
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"text": [
"You have an object which contains all your data (Model) . And a view which displays all your data. With normal mvc (model View controller) your object with data does not know when a value is changed in your view (E.g. You select your age, the object does not know you set. With mvvm the model listens to the view, and the view listens to the model. That way if you update age in the view, the model will be updates with your selected age, and vice versa."
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eqi08x | how does a cell phone know how much battery is left? | Technology | explainlikeimfive | {
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"text": [
"While the answer about battery voltage is correct, it’s incomplete. Modern phones are equipped with a “Gas Gauge” IC called a Coulomb Counter. It “counts” the amount of energy going into or out of the battery cell, so as to estimate the remaining charge. The phone uses that data along with cell voltage and cell temperature, combine it with some intelligence about the cell’s history/age to determine the charge level. URL_0 URL_1",
"Phones mostly use Li-Po batteries because you can form them to thin but wide and tall shapes like the shape of a phone. You can do it a couple of ways, either measure how much electricity has been used, this works because you know how much the battery can hold. Or you can measure the voltage. When fully charged there will be a known voltage, I don't know exactly what bit something like 3.7v for example and when you discharge it then it will slowly drop to a fully discharged voltage. By measuring that you can figure out how much battery is left. How the voltage dropping not affecting the phone well that I can not answer."
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eqji5z | How do CPU transistors *physically* read data? | If I understand correctly, transistors act as a switch, as in open/close. I also understand that information is in binary code, meaning 0 and 1 (for those who don’t know, example: the letter “A” = 01100001) But from a physical standpoint, how do the *billions* of transistors know where to start when they receive information? How is the information carried? Electrons? And do transistors just start on a random part and figure out the rest? Or is everything in order? Please ELI5. | Technology | explainlikeimfive | {
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"Not exactly an ELI5, but I did watch a great youtube series of a guy making an 8bit computer from basic logic gates, and it really helped me understand at a more basic level how computers work. Ben Eater on youtube, or URL_0 might be worth looking into.",
"As far as how 0/1s are carried, yes essentially electrons. But think more about how a transistor works. They basically have 2 input wires, and one output wire. If both of the input wires are receiving electricity, it outputs electricity to the output wire. That's *very* simplified, but good enough for ELI5. So, transistors don't know what the heck a 0 or 1 is. They're just dumb hunks of silicon. But, we can treat \"electricity is flowing\" as a 1, and \"electricity is not flowing\" as a 0. If the transistor is a switch connected to a lightbulb, if the lightbulb is on we can call that a 1. The transistors are chained in crazy ways to take those inputs and transform them somehow (like multiplying numbers or whatever). The details are hard to ELI5, or even ELI50. Just like a factory can take flour, sugar, sawdust, and soybean oil and output crackers without us knowing the exact process of how they do it, it's easier to think about parts of a CPU the same way. They take some sort of input, process it somehow, and produce output. But it's all just transistors connected together. To send a CPU information, we can send electricity to each pin that we want to receive a 1, and don't send electricity to the rest. The transistors in the CPU don't randomly start processing the 1s and 0s. We need to tell the CPU when the input is ready. So there is another CPU input that we send electricity to so say \"the input is ready, start processing it\". Likewise, the CPU will send electricity to an output wire when it is done setting it's outputs to 1/0s. CPUs are crazy complicated - especially modern ones. The above only scratches the surface. Hopefully it helps a little.",
"There is at least one pin (the [metal bits that make contact with the motherboard]( URL_0 )) that is dedicated to a *clock cycle*. A signal comes in from your motherboard that only ever cycles from 0 to 1 to 0 to 1 over and over at a regular cycle. This sets the pace of your CPU. The reason it sets the pace is that *all other signals* are compared to that clock signal. IF the clock signal is 0, and IF this other pin is getting a 1, then this other pin will output a 1. Or IF the clock signal is 1 and this *other* other pin is also a 0, then this other other other pin will output 0. Or 1. Or however the logic gates in the CPU are arranged. That's what transistors do. There are two inputs and an output. The two inputs determine the output, which is how you build a logic gate. [Here is a gif of logic gates simulated using water instead of electricity]( URL_1 ). As you can see, you can set up different kinds of logic, such as the AND gate, which says that the output C will only be 1 (ON) if *both* the input A and input B are set to 1. There is the OR gate, where output C is 1 if either *or* both A or B are 1. Compare that to the XOR gate: C is only 1 if A *or* B is 1, but C will be 0 if *both* A *and* B are 1. Or the NOR gate, where C is only 1 if *neither* A nor B are 1 (in other words, if both A and B are 0). And so and so forth. There are a lot of different kinds of logic gates and you can combine them to build bigger and bigger logic trees with more complex outputs. That's what your CPU does. Take two (or three, or more) inputs and compare them against a logic gate, then output the result of that logic gate. Your CPU has a *lot* of transistors all doing that at the same time and using outputs from some transistors as inputs for other transistors, and outputting signals to other parts of your computer that ultimately do the same thing. The clock cycle mentioned forms the backbone of the process by giving the CPU the most basic signal to compare to. The clock cycle also gives your computer a very predictable signal to check against. For instance, what if there's a part of the memory that just reads \"11111111\"? How does your computer know how many 1s there are in a row? Well, because it compares that to the clock cycle, which is always going 01010101. Even if the signal coming from the memory is just ON for a while, because of the clock cycle the computer will keep checking and potentially getting different results based on other inputs. The other major part of the computer is the memory. If the clock cycle gives your CPU one backbone signal to compare against, what else is it comparing? That's what the programs are for: they tell the computer to do something based on what the clock cycle is, along with other inputs. The program is stored in your memory as more sets of 0s and 1s. The computer sends instructions to the memory to find what's at a certain location and begins pulling the bits from that location. It does get a little complicated, because your computer uses a couple different kinds of memory. Some kinds are permanent but too slow to be practical, and other kinds are really fast but can't permanently store data. So you combine them: take a little time to pull the whole program from the permanent hard drive and load all of it into the volatile (not permanent) RAM. Then you can read what you need from the RAM fast enough to keep up with everything else. When you first boot up your computer there is a special little chip and set of memory on the motherboard called the BIOS. The programs in the BIOS never change (except for when someone *really* knows what they're doing and takes special, deliberate steps to change it). The BIOS has instructions on how to communicate between the stuff going on in the CPU and the actual, physical pieces on the motherboard. It's still a bunch of logic gates, but they're particular to that motherboard and contain *firmware* - permanent, unchangeable programs - to interact with the motherboard. As part of the boot-up process, the BIOS gets power from the power supply and makes its own clock signal, which it uses to turn on all the rest of the parts of your computer, including the CPU. It also has very simple instructions that tell the CPU how to pull your operating system program out of the permanent memory and put it into the RAM, where it more or less stays for as long as your computer stays on.",
"There is a reset signal that is automatically triggered when the system is powered on that put the CPU in a known initial state. You add special connections and transistors in the CPU to accomplish that. You add extra transistors to wires and pull them to 1 or 0 with the reset signal. Exactly how it happens and what part you need to clear depending on the CPU. There would, for example, be no need to clear the data part of the cache is you just set the address part as no address so you likely lt them have a random value because it cant be read. It is quite easy to build a circuit that when the voltage rise send a single reset signal. You use a Schmitt trigger."
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eqjk6p | how do open air markets keep fish fresh? | I don’t live anywhere near a fresh fish market, but my sister sent me a video where they have the fish sitting out for sale in the open air. I always thaw frozen fish in my refrigerator and cook it immediately; how do fish mongers or sellers keep it fresh in the open air markets? | Technology | explainlikeimfive | {
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eqs5re | Why are other standards for data transfer used at all (HDMI, USB, SATA, etc), when Ethernet cables have higher bandwidth, are cheap, and can be 100s of meters long? | Technology | explainlikeimfive | {
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"USB cabling and receptacle buses are cheaper than ethernet cables. USB has greater port density, and will fit cleanly into thinner form factor platforms. USB 3.0 has ~5 gbps transfer rate, whereas cat5e gets stable 1gbps. Getting 10Gbps typically requires cat6e ethernet cables or fiber, which are not exactly flexible and definitely not as cheap. Copper ethernet is also rated for 100 meters; you would not get very good throughput at 100s of meters on copper. Granted, this isn't typically a requirement for USB based eqpt either. Eli5 edit: 1. USB cable and especially the equipment you plug into (buses/controllers) cheaper than ethernet 2. Fit more USB ports in tiny space (known as port density) 3. USB faster than ethernet for price, especially on modern solutions like USB-C 4. Ethernet is better at longer distances, which is why networking equipment uses it, but your keyboard does not need to",
"You had the misconception of ethernet cables having higher bandwidth. That's where your root of your confusion.",
"Gigabit ethernet max. transfer speed: ca. 1 Gb/sec HDMI 2.1 max. transfer speed: ca. 42 Gb/sec",
"So what is being conflated here is Ethernet cables and Ethernet, HDMI cables and HDMI, etc. We need to talk about the physical layer and the protocols separately. Ethernet is a protocol that can be run on top of a number of physical layers. Most people think of Ethernet cable as twisted shielded pair. This is a type of transmission line that has an impedance of about 100 ohms. Depending on a number of factors like the dielectric loss, and how uniform the impedance of the line is different sorts of transmission lines have different bandwidths. The usable bandwidth of a CAT6A cable is about 500 MHz. The rest of the bandwidth comes from additional channels or QAM modulation techniques. Now what are SATA cables? Well they are differential pair signals as well. So is HDMI, copper differential signal pairs. Now imagine you want to send a signal down a transmission line and you want it to switch on and off at 20 GHz. Well you can actually do that on any sort of cable, the question really is just how much of the signal will actually make it to the other end and what it will look like. If its just loss and not lots of horrific reflections then you just need to just put repeaters in the cable or make it short enough. If the transmission line has a lot of dispersion then the shape of the signal will get lost and it will become hard to \"see\". These factors are often shown with something called an eye diagram, the more open the eye is the better the signal integrity of the communication channel. The fact that Ethernet can be 100 m long means that the dispersion and the loss of the cable have to be low at the frequencies that protocol is used at. As others have pointed out HDMI has a lot more bandwidth so the cables can't be as long or the transmission line quality has to be better. Cheap cables mean lower transmission line quality. The very best cables that are not optical (in terms of bandwidth) tend to be rigid pipes that are quite a lot like coax but have the center conductor basically floating in air with little spacers, these get up above 100 GHz.",
"This comes down to the intended use of the Device more than anything else. HDMI to Ethernet adapters do exist, and Ethernet can obviously handle the bandwidth required for a 1080p video stream, but a lot of the \"extra pins\" HDMI has cover audio, error detection, frame timing etc. Classically the interface to provide a usable signal on the video output end is provided by the input device, and monitors, TV's, etc tend to follow this pattern. In the case of USB, the devices themselves have to be smart enough to tell the computer how they're connecting and what sort of functionality they'll perform. Bandwidth isn't the end all consideration when determining what the most efficient way to transmit information is. While transmitting the required signals via ethernet may be possible it wasn't designed to support the wide array of applications better suited to specific connector types.",
"Ethernet generally cannot transmit power, or requires quite a bit of componentry on both ends to do so. It therefore doesn't work well for things like keyboards, mice, flash drives that require a power source. It doesn't have the sheer bandwidth needed for HDMI or displayport, or the very low latency and, until recently, high bandwidth needed to run SATA. 10Gb/s ethernet endpoints are still very expensive and power consuming.",
"I know this comment will never be seen, but Ill try anyway. Data bandwidth is not the only measurement for a cable, and many cables are used because they fill a role no other cable will fill properly. HDMI for instance was shoved down our collective throats by the media 'powers that be'. It has 19 wires inside it, and performs a massive series of handshakes both to negotiate things like display resolution (through EDID) and copyright protection (HDCP). An ethernet cable cant pass this signal without a translation device (which exists and is known as an HDMI extender). Meanwhile, HDMI wires are notoriously finicky over medium to long distances. RG6 with a BNC connector is often used because the actual termination (bit on the end) can be secured. BNC was actually created by the British Navy iirc for that express purpose. The equipment it is used on does not require ethernet throughput. Fiber is frankly very high on the list of wires that are great. Extreme data transmission speeds are possible, and you can run it for extremely long distances without issue. There are also secure connectors that pretty much assure the thing will not pop out by accident. The downsides are its fragility, and lack of easily available equipment for it to be used with. & #x200B; TLDR; Wires are used for all kinds of reasons, not just data throughput.",
"The easiest answer is that USB has built in standards for device detection, drivers, and is designed to handle a much broader range of devices. HDMI has built in negotiated standards for DRM, and the port is meant to be easier to install in tighter places. With the addition of Thunderbolt to the USB 4.0 specification, fiber optics are now used for handling stuff previously relegated to PCI cards inside computers. Finally, power. HDMI includes Ethernet for transport. USB can handle up to 100W of power with the proper Type-C cable Bottom line, Ethernet is designed to do one thing - networking. We can sometimes shoehorn it to do these other tasks, but imagine an Ethernet port on a thin tablet today.",
"In addition to things others have mentioned, the RJ45 connectors you are probably thinking of aren’t very durable (the clips tend to break off if you unplug and plug back in often). Unlike USBc they also aren’t reversible.",
"There are many advantages and disadvantages to each type of transportation. Since every industry is unique and has different costs and profit margins, companies choose the method that fits them best. For example, HDMI works best for transferring videos, USB works best for transferring files to small portable devices such as flash drives. SATA works best for external hard drives.",
"In addition to what everyone has already said, Ethernet cables are extremely inflexible. None of those could be reasonably routed inside of a PC case (ie SATA replacement) and would be clunky and fragile to carry around with you constantly.",
"ELI5 answer: Because it's easier to have different types of plugs for different things. As for a more technical explanation, I'm copy/pasting what I've put elsewhere (only slightly edited) ---- 200 meters is the limit for Cat5, 100 for Cat7. The bandwidth for Cat7 which is 10 Gbps which beats USB 3 hands down while the newest standard for HDMI is 18Gbps. The form factor of RJ45 is only that way because of standards. It doesn't have to be the size or shape that it is but good luck getting every computer and NIC manufacturer to adopt a new one. As for the max length of a cable, there are such things as \"repeaters\" which are insanely cheap these days. Additionally, AWS 24 ethernet cables have been used for VGA cables in the past. [Here's a link to a converter just for this purpose]( URL_1 ) HDMI nowadays has bandwidth up to 18 Gbps but previous versions went up to 10 Gbps, same as Cat7. In fact, [there are converters just for this purpose]( URL_2 ) So, now that you've read all of this, the reason is because of technical standards. After all, it would be hella confusing if everything plugged into the back of your computer via RJ45. On the other hand, it's only eight wires and it's extremely easy to wire in another plug on the cable and save yourself some money. ---- Edit: To add some history as to why we have different plugs: Computers didn't always have standards when it came to hardware. Anyone could make a component and as long as it fit the motherboard, you could sell it even if the drivers, software, and cables were completely proprietary. Along came modems, printers, and sound cards and it became such a nightmare to support that eventually standards for things were introduced and manufacturers were expected to conform. By then, we had so many pieces of hardware out there that the most popular ones were (mostly) the ones who benefited since they had the largest market share and had the highest financial agility to adopt or influence the standards. Because of this, those different cable types were kind of cemented in place and became commonly used, spreading forward to the plethora of cable ends we have now. Sometimes, however, technology advances and we can get more into a smaller area. We see this mostly commonly with USB plug types. Sometimes we only need a limited amount of bandwidth or we just plainly have a very small amount of room. For example, could you imagine using one of [these]( URL_0 ) on your PlayStation controller??? So we have different cable connector types for historical, bandwidth, expense, power requirements, or space reasons.",
"for HDMI, it is lossless and has 48Gbps bandwidth (with [hdmi 2.1]( URL_0 )). So it's not quite like you've thought"
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eqslfw | Real Time Ray Tracing and why it is so computationally intensive | Hello redditors, I understand that RTRT (lol) is very intensive due to actually calculating light ray paths and such, but I don't know "how" or more specifically which part of the rendering pipeline requires the most effort that makes it as hard as it is Can the reply also include what specific RT hardware does that is different from using normal GPU shader cores to accelerate RTRT? | Technology | explainlikeimfive | {
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"Ray tracing isn't so much hardware as (just like other rendering), a mathematical way to turn a 3d scene into a 2d image. The computer has the numeric geometry of each object in the scene, and information about the lights etc. But it has to turn all those numbers into a picture. That's rendering. Ray tracing is best explained by its [Wiki page]( URL_0 ). Without ray tracing, graphics are created using rasterization. In rasterization each object in the scene is broken up into triangles, and each triangle has a position and color. That produces a very basic image. A series of shaders are then applied, giving the triangles an image texture, adding light and shadow, blur and focus, etc. The result can be pretty good and we've pushed shading tech a long way. But it's still not as good as raytracing. Ray tracing hardware is just a GPU that's very good at the calculations used in raytracing an image. If it can do that fast enough to build a whole frame 20 or 30 times a second, you have a real time raytracing graphics card :)"
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eqtg1a | How are files compressed? | Technology | explainlikeimfive | {
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"Compression is essentially a TL;DR for data. It involves finding a more concise way of providing the same information. For example I can tell you to type 00001111000011110000111100001111000011110000111100001111000011110000111100001111... Imagine that goes on repeat 1000 times. It wouldn't fit in this comment. Or I can just say: repeat \"00001111\" 1000 times. It communicates the same information but fits in a single sentence.",
"There are 2 types of compression - lossy and lossless. Lossless compression usually find some recurring patterns and replace it by something smaller. Much like btw = by the way. (Google RLE as one example) Lossy compression are specific to type of media (image, video, audio, ..) and they are based on properties of human eyes/ears... Eg your eye does not see a difference between a 'light red' and 'very light red' so the image is altered to simply a 'red' (Google JPEG)"
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equ4hm | Why do batteries seem to "recharge" ever so slightly when not in use? | Technology | explainlikeimfive | {
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"A battery is in simple terms, some metal that is involved in a chemical reaction which frees up electrons. This process causes the metal to corrode, serving as the chemical energy source of the battery. The specific vary by battery chemistry and layout, but the corrosion can flake off to reveal fresh metal or some other reaction can occur that clears up the electrolyte enough to work a little more. In short, batteries are chemicals reactions that cause physical change, so various things can happen. Be careful playing with them. [Electrochemistry: Crash Course Chemistry #36]( URL_0 ) 9 minutes"
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equonm | When you open an image in notepad, why does it come out in seemingly infinite numbers of gibberish characters? | Technology | explainlikeimfive | {
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"So you've probably already heard that data on your computer is stored as binary, a string of 1s and 0s, called bits Those bits have meaning to your computer, for instance, text can be encoded by bunching the bits into groups of 8 called a byte, like 01100111 That particular byte, is the ASCII code for the letter G (ASCII is one way computers use bytes to store text) Pictures are also stored as bytes, but the meaning of each byte is going to be something different, like the amount of red in a given pixel That byte that is a G when read as text, is also the number 103, so in an image file, the computer might understand it as \"this pixel has 103 out of 255 amount of red in it\" Because readable text is only a small amount of byte-to-text conversions [(here's a table of every possible ASCII byte)]( URL_0 ), and most of the others are special instructions, originally for old text-only computer terminals, Notepad just does its best, and displays whatever it thinks this text might mean"
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er07l8 | Is it harmful in the long-term to charge my iPhone fast more often than slow? | Technology | explainlikeimfive | {
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"Most modern batteries have some circuitry that won't let it built up excess heat or degrade, phones all have this - so it will only ever charge at a safe rate The socket in your car may just be low amps. You could charge faster in your car by buying an adaptor"
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er0jso | How does a CPU work compared to a GPU? | Technology | explainlikeimfive | {
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"CPUs are general purpose processors, capable of doing *anything* but not very efficiently. You can freely load software onto them and run that software, it supports multiple tiers of operation (separating the operating system like Windows from its applications like firefox) and a ton of other features that make it appropriate for running software downloaded from the internet or bought on CD-ROM (haha, those days are over). GPUs are incredibly parallelized, like a CPU with a few hundred CPU cores and lots of math capabilities. However those cores lack the ability to efficiently communicate with each other and also most of the features that modern CPUs have described above. They're best used for straight-forward calculations that requires lots of cores that can all run similarly but independently. Rendering 3d images runs really well on GPUs, but true decision making logic runs best on CPUs.",
"I think the Mythbusters covered this well. URL_0",
"A CPU is designed around a central processing core. This core contains the registers for short term memory of live numbers, several processing units for different types of calculations such as one for integer arithmetic and one for floating point arithmetic, and all the buses and multiplexers to send data between the different processing units, registers and memory. A large part of the processor is dedicated to the control circuit which takes inn the machine code and translates them to detailed optimized commands for the rest of the core. The assumption in this design is that you have a single set of data that you need to do a lot of calculation on where the result of one calculation depends on the output of the previous calculation. So a lot of effort is put into making this one single thread of calculations as fast as possible. A GPU on the other hand is very different. When working with graphics you often wants to do the same type of calculations on lots of different points in space or pixels on a canvas. And because a lot of the space and power in a CPU is dedicated to the control logic which does not see any data at all but for graphics workloads it will see the same machine code over and over again, the GPU uses the output of one control unit in multiple different cores. So each core works on different data but executes the same code as it gets its commands from the same control logic. This saves a lot of space and power which allows a GPU to have thousands of cores. Especially as the cores are made light weight by not including most of the processing units that a CPU would come with. This makes a single GPU core slower, not just the clock frequency but it also takes more clock cycles to complete the same calculation. However because you have a lot of GPU cores you can do a lot more calculations then in a CPU. The disadvantage is that you are a lot more limited in the types of workload you can do in order to get that performance. With anything but the most basic games you need a GPU to do the graphics processing as the CPU is just too slow for this type of work. However most consumer CPUs today does include a small integrated GPU on them which can be used for games. But as this integrated GPU is only intended for lighter work such as browsing, desktop composing and showing video a lot of gamers opt to buy an external GPU on a separate graphics card. This is because games can use the GPU quite a lot, not only for graphics but the GPU is also suitable for simulating physics as well."
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er2pu1 | How can popular social media websites handle the large amount of network requests its users put on their application at once? | Technology | explainlikeimfive | {
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"If your device is the user, the website has many servers running it. And between you and those servers is something called a load balancer (often multiple machines, acting together), which help to balance the load. Let’s say a server can handle 10 requests at a time. But there’s 1000. There may be 100 servers running the website, and one machine between those 100 and you, to allow everyone to use the site simultaneously."
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er5hpe | What sort of technical, broadcasting setup is needed to bring us these NFL Championship game replays, from any angle, seconds after they happen? | Technology | explainlikeimfive | {
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"While the technology can be advanced, the concept is simple. It works with one camera, or 50, the only difference being you obviously need more people to work with more equipment. So how does it work? Well there's a replay machine. It records whatever is fed into it. Like other video stuff, you can cut clips and out them together manually, say for highlights after the game. But the operator also has the quick buttons called in and out. If you hit the \"in\" button, it will save a previously selected time of video starting when you hit the button, for example it will save the next 30 seconds in a seperate que. The \"out\" button is the same, except it's the previous 30 seconds. This allows a quick instant replay of the goal, or the big hit. After that (or simultaneously) they can create a longer replay if there's a challenge, or delay in the game giving them more time to show stuff. I work video production for hockey. Here is a step by step how it works. Player scores a goal. The replay operator counts to 5, and selects his \"out\" button, saving the previous 7 seconds for review. That is enough time to show the goal, and the celebration. He has three camera angles, and quickly hits three hot keys to show angle 1, the 2, then 3. For example it would be Shift and #1 on the keyboard to save angle one. This is queued up in the \"A\" spot, available for immediate review. All of this process takes less than 5 seconds. He then goes back manually, and creates a longer clip, perhaps showing the whole play develop on the other side of the ice. If there is time before play resumes, maybe broken equipment, or a commercial break, then we might show this longer video on the scoreboard. Otherwise it gets saved for a game highlight video. Now you're thinking that seems easy with only three cameras, so how do they handle it with more cameras? There's a few ways to do it. Perhaps there are different replay machines. For example, I'm responsible for the replays on camera 1-4. And the next guy is responsible for replays on camera 5-8. What is also possible is that the replay operator only has to select the time, and then the director has a different feed for each individual camera. Rather than the replay operator giving a one video made of all the camera angles, the machine will output each individual camera angle to a different channel, so the director can make the choice which one to go to. In this case the switcher (person who switches from camera to camera) is doing the same thing they normally would, except instead of it being live, it's recorded from the replay machine."
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er6b5b | My ISP is having problems and my upload speed is really low, but my download is fine, so why are pages taking so long to load? | Technology | explainlikeimfive | {
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"What's your upstream latency like? Half of 'loading a webpage' is requesting the webpage. If you've got high latency or packet loss on the request, it can take a while to reach the server. If you've then got high latency on the return trip too, that will make things take even longer",
"The TCP protocol used for websites and most other internet applications requires uploaded acknowledgement of packets. So the websites sends part of the webpage, and your system has to acknowledge that you got it. If you're having upload problems, and the acknowledgement packet didn't get back to the server, the server has no way of knowing if you got those packets or not, so it resends them. So you can end up with a lot of retransmissions from the server, which will slow things down."
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er6w9i | How does looking at technology (phones, laptops, TVs, etc.) strain your vision? | Technology | explainlikeimfive | {
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"A couple issues here. For one, reading. This is true of anything. If you're reading books all day, the small print can be strain on your eyes. Believe it or not, no, you can't actually get away with looking at a book all the time. You need to go outside and look at less \"taxing\" things. Next, blue light. Your phone? It glows. It's basically a lightbulb capable of producing colored displays, even if only a weak one. Imagine staring at a lightbulb all day. Not a very good idea. Imagine some guy gently tapping your shoulder all day, every day. It might not hurt at first, but your shoulder will get sore eventually.",
"For me it's mostly the distance that strains my eyes, but the light is also an issue if there's a contrast with the environment [eg a bright screen in a dim room]. I'm nearsighted, so if I close one eye when using my phone, both eyes are \"unfocused\" which doesn't use the muscles, but the one eye is focused well enough to read what's on the screen. However, crossing both eyes to read something close to my face causes muscle strain over time."
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er9fko | How a Pineapple router works? The hacker/intercept device? | I saw it on an episode of Silicon Valley. It's some type of middle man between the router and the users. All the youtube videos seemed a little too advanced for an ordinary non programer guy like me. So I have the extremely simple explanation of "It's a middle man" which tells me close to nothing and then advanced tech from youtube which I can't understand atm. Please help. Thanks! | Technology | explainlikeimfive | {
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"It pretty much scans the area for WiFi networks, then it can act like said wifi networks, to get WiFi devices to connect to it as a network it trusts. Once connected to the pineapple you can run explore or run man in the middle attacks (MITM). Hak5 has good videos on how to use the devices, since they made them.",
"Based entirely off the description of \"middle man\": A man-in-the-middle attack (MITMA) is a common cyber attack where a bad actor (commonly called \"Oscar\") intercepts the messages one person (commonly \"Alice\") is sending to someone else (commonly \"Bob\"). So normally, Alice sends \"hello\" to Bob, and Oscar is completely absent from the situation. Alice \"hello\" --- > Bob With a MITMA, Oscar tells Bob his name is Alice but tells Alice his name is Bob. Now Alice and Bob _think_ they're talking to each other, but really they're both talking to Oscar. Alice --- > Oscar --- > Bob Now, when Alice sends \"hello\", Oscar gets the message first. Oscar can choose to just pass it on to Bob faithfully (meaning without modification) and now can record all of their communications (\"hello\" isn't very interesting, but maybe Alice sends her SSN next). Alice \"hello\" --- > Oscar \"hello\" --- > Bob Oscar can also choose to modify the message, e.g. Alice sends \"hello\", and Oscar tells Bob \"good bye\" or \"send me your password\". Alice \"hello\" --- > Oscar \"password?\" --- > Bob In these scenarios, the man-in-the-middle is the same as Oscar is the same as the Pineapple router."
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erbxl7 | How do subtitles end up with a linear drift? | Does that mean different files for the same movie / episode can play at different speeds? | Technology | explainlikeimfive | {
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"Yes, it does mean that. TV networks [frequently speed up shows by a few percent to fit in more ads]( URL_0 ), so it's entirely possible that there exist multiple files of the same video at slightly different speeds, giving them a slight linear subtitle mismatch.",
"As MrOctantis says, depending on the source may vary a bit the video length. Also may be affected if cuts have been edited, intros, etc. The subtitles, at least .srt which is the format I know, are text related to a time gap. EG. file has 00:10 to 00:12 \"Hello\", and 01:20 to 01:25 \"die potato\", will sho said texts at said time, if theres an added intro you will get those during the intro, and if cut scenes are cut shorter they will come before due time."
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erdlb0 | on old fashioned ships from the 1600s pirate times etc I’m guessing they had fires to keep warm how did they keep these safe and protect the wooden ship from burning? | Technology | explainlikeimfive | {
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"In the age of sail, ship's cabins were poorly ventilated, and dozens (or even hundreds) of men would keep the cabin more than warm enough with their body heat alone when they were sleeping. When walking about the deck of the ship, warm clothing was about all that could be relied on. Ships were extremely flammable, with not just wood and cloth but also tar for waterproofing the ship. While there were ovens introduced later on, they were more for cooking and were not designed for heating the ship. You can find more info here: [ URL_0 ]( URL_0 )",
"As someone has already said, fires weren’t really used for warmth, but ships even in the 1500s had a brick kychen down in the hold for cooking. They would only be able to use this in fair weather as the hatches would need to be open to let the smoke out. Most of the time food was dried or salted or more likely simple thrice baked biscuits.",
"There were seldom open fires on a ship due to the extreme danger that a fire represented. For certain specialized cases (e.g. whalers rendering whale oil) there would be fires that were carefully watched. Even matches were a significant danger. The term \"the smoking lamp is lit\" was still used up until recently in the Navy to indicate that smoking was allowed. This came from the days when a literal lamp was provided for sailors to use in lighting their pipes or cigars. No lamp, no smoking.",
"The British Navy adopted [Brodie Stoves]( URL_0 ) from 1781to 1819 for cooking on most royal navy ships. Before that they did have other types of firehearths.",
"The worst were whaling ships. The decks were covered in oil and blubber renderings. There are many reasons working on a whaling ship would be miserable (operating in cold regions), but the restriction on fires for heating would be brutal."
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ergj2g | In mobile data, does every smartphone connected to the tower get one frequency? Like I get 1836 MHZ, you get 1837 MHZ etc? | Technology | explainlikeimfive | {
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"No, we share frequencies and take turns. In the old analog cellphone days, each conversation required two frequencies. One for talk and one for listen. With digital cell service, dozens of conversations can use the same frequency by breaking the digital audio up into packets and sending them in turn. It is like taking turns talking, but it happens so fast, you don't notice it. Another method allows transmissions to share frequencies by using a unique code for each. The receivers filter out all the codes except for the one it has been instructed to listen for. It is like listening in a noisy environment for speech in your language."
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erja9t | How could Sputnik 1 be guided without a pilot or radio control? | Technology | explainlikeimfive | {
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"They were going for orbit, not *nearly* as precise as our current ability to tweak orbital parameters. They basically got the 2nd Stage deployed correctly, lit it, then released Sputnik when the 2nd stage was spent. Both reached orbit and both degraded within months.",
"Sputnik was in no sense guided. It was orbiting, thanks to physics, but \"on track\" was just a result of its inability to change track."
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erjlb6 | Why do whetstones have to be wet? | Technology | explainlikeimfive | {
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"They don't have to be wet to work, but if you use them dry the pores in the stone will quickly clog up and it will fail to continue to sharpen, as well as destroy the stone. Using them dry will also damage the stone immediately, as the water or oil (depending on the type of stone) is used to lubricate the sharpening action."
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erkeks | Why do smartphones ask us to hold the phone still while taking night mode shots? | Technology | explainlikeimfive | {
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"The nighttime mode takes multiple photos and uses them to build the final image using filtering software, when the camera moves, reduces the number of usable images and decreases the quality of the final image."
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erlhca | How do rocket launchers that have lock on capabilities know what to lock on to. Like, how do they know what's a vehicle and what isn't? | Technology | explainlikeimfive | {
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"Alot of missile Heads have infra-red cameras. {cameras that see heat} So they lock onto the heat signiture of the target. Engine is 98 degrees c it sees it it follows 98 degrees c give or take."
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ernysc | Why are CPUs Sold as Chips and GPUs sold as graphics cards? | In desktop PCs, basically all CPUs are just the chips which you can then place on the motherboard. GPUs are sold as graphics cards like the 2080 Ti. Why is this and what is the purpose? | Technology | explainlikeimfive | {
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"There aren't many cpu makers, and motherboard companies follow cpu regulations/data sheets when drafting their designs. They also incorporate some rarely changing standards, like ddrX ram slots, pcie connections and the like. But pci express slots are the reason why gpu chips have to come with their own boards. Imagine if motherboard companies had to incorporate vram and other circuits specific to each gpu chip manufacturers designs. You'd have an exponential increase in board types, beyond the standard Intel vs AMD mobo. It'd be Intel processor X slot and Nvidia GPU Y slot, or Intel and AMD, then you'd have to make mobos for each number of gpu's a person might want, so an Intel X processor GPU Y x2 board etc. Marketing and manufacturing nightmare. So considering that each pci slot is essentially an extension of certain pins on the cpu to aid in connecting complimentary cpu type stuff to it, like a gpu, mobo manufacturers decided to make a standard which puts the particulars of cpu extensions in the hands of any company willing to provide a chip, or set of chips, on some board, which fits a pci type slot for whatever purpose. Intel and AMD (and the few other cpu manufacturers that technically exist) are lucky that motherboard manufacturers didn't create a cpu slot standard that forces them both to provide their own boards/adapters to fit a \"cpu express\" slot or something like that. Instead, motherboard manufacturers decided that providing two types of each motherboard they make was doable. So you see either Intel based, or AMD based motherboards, all with the same kind of pci/pcie slots for expansion of each cpu. And in turn, gpu manufacturers provide their own boards, along with any other manufacturers of various expansions, like USB slot expansions, wifi chip expansions, audio processing, ethernet cards, Bluetooth cards, custom made security devices, etc.",
"I think there's some truth in the other answers, but I think it's mainly just tradition. Before GPUs, CPUs went into motherboards in the CPU slot and graphics cards went into a PCI slot along with network cards and whatnot. When GPUs appeared they were bound to the video system to do 3D graphics, so went on the video card rather than needing a new kind of motherboard with GPU slots. Many other computer architectures (not PCs) have a system where there's no CPU/RAM on the motherboard and you plug CPUs in on cards - PCs could go that way again (the Pentium 2 was a bit like that)."
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erofom | Why is account security how it is? | What advantage is there to having to have passwords of a certain length with requirements for upper and lowercase letters, numbers, and special characters? Wouldn't that just reduce the number of passwords that have to be tried? For example, if it has an 8 character minimum hackers can skip all 1-7 character combinations, as well as all combinations that don't have at least one uppercase, lowercase, number, and special character. In addition, these requirements force you to make hard to remember passwords, which will cause many people to write it down somewhere or store it in their phone For security questions, why does it usually not allow you to write your own questions? Instead, you have to pick from a few different pre-made ones, which are inexplicably usually the easiest info about you to find. What your favorite sports team is, favorite pet, your street name growing up, mother's maiden name... all of these things can be found with simple searches pretty easily For both, they often make it so you can't read the data as you input it, making it more likely for you to put in wrong info and get locked out later This has always seemed really obvious to me, but no one else talks about it so i'm guessing there's something I don't know that explains it | Technology | explainlikeimfive | {
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"* The number of 8 character passwords is larger than the total number of passwords 1-7 characters long, by a factor of 100. * Requiring additional character sets increases the potential complexity of passwords. If you only use numbers and letters, that's a total of 62 possible characters. If you add the standard special characters, that's \\~82 possible characters. For an 8-character password, the difference is (62)\\^8 vs (82)\\^8, or 218 trillion vs 2 quadrillion possible passwords. * Length is still generally way more important than complexity. \"ThisIsMySuperGoodPassword!\" is a way better password than \"j#0hn1987\\*$\" since it's significantly longer, while being easy to remember. * Standard security questions are used because that's info you're more likely to remember, making it easier for you to recover your account if you need to. People hack passwords, generally, in one of three ways. They can find a big list of a bunch of leaked passwords and try every single one on the list, maybe with a few permutations like replacing A with 4 or I with 1. This is called a dictionary attack. Then can also run a computer program that will try every single possible password, possibly with some of the blanks filled in (like \"it starts with a 1\" or \"it's x characters long\" or something like that). This is called a brute force attack, and can potentially take thousands of years (though you can cut that down by running the computation of lots of powerful computers at the same time). The third, and best technique, is to trick you into giving them your password. This is called social engineering, and is commonly done via phishing, a technique where they might send you a fake email from your bank saying you need to log in for some reason, but the link in the email sends you to their website that looks like your bank's, and you just feed them your login credentials.",
"Part of the reason for the requirements we have is because we have an entire generation of people who grew up with those requirements. Early Microsoft windows could only handle up to 8 character long passwords, anything longer just got truncated in the background, so the requirements for mixed case and special characters was to squeeze the most complexity out of those 8 characters to slow down password guessing attacks. Security specialists have known for ages that the most common requirements are counter productive but for many people in the workforce now that is how it's always been done. Most of the talk about the shortcomings of password complexity is in academic circles so not widely publicly known but XKCD is probably the most quoted post in relation to retiring password for passphrases URL_0"
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erpsdi | How does flying low keep you off the radar? | Technology | explainlikeimfive | {
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"When using radar to find flying objects, you are limited by what is known as line of sight. This means that you cannot see through obstructions, such as the terrain. The lowest point your radar signal is restricted to is the horizon from where you are. Since the Earth is round, that point gets lower the farther away it is from you. So when an airplane is flying low enough at a distance, you won't be able to see them as the curvature of the Earth prevents your signal from reaching them. This is why many nations try to place their radar sites on higher elevations and some countries even have specialized aircraft with powerful radars on them.",
"The terrain does block the line of sight of the radar. It literally can't see your plane when it is behind a mountain. Because of this air surveillance likes to put radars on top of mountains and towers. Also, and this is an equally \"blinding\" factor: The terrain isn't plain, isn't made of the same material isn't standing still (like trees moving in the wind or water waves on the ocean) and isn't quiet in electromagnetic emissions means (radio signals, TV signals, WiFis, other emisisons on every possible frequency band). On top of this all these factors literally mutilate the radar signal. Every edge, every different shape and every different material all reflect, refract, shape shift the radar's EM waves so much that it is impossible for the radar's detector to distinguish between a plane flying in all these \"noise\" and the noise itself. The higher you fly, the more homogeneously spread the noises energy is in the sky and the higher the possibility to dedect a single object. IIRC the safe to detect height is about 5m on open seas and 15m on land. Thus youd have a hard time \"sneaking up\" below the radar without crashing.",
"What others have said regarding terrain is true. That said, radar design is all about tradeoffs. If they're good at differentiating target altitude, then they're poor at something else, or at the very least they are more complex and expensive. Air defense radars are designed to detect targets in the air, and designers must often design them to be effective against \"most\" targets, or perhaps against the most dangerous targets. So, to cover the effective altitude of \"most\" targets, a radar might be designed to cover medium to high altitudes very well, but the trade-off is reduced detection at low altitudes."
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erq0xg | How TV Networks find specific clips of things that happened decades ago? | I was just watching The Late Show with Stephen Colbert and they showed a couple of old clips with contradictory statements by Alan Dershowitz, just seconds of videos from decades ago. Everytime I see something like that I wonder: How TV Networks catalog all these clips in order to find them when they're useful for their purposes? Edit: I don't mean the database where they get those clips from, but the actual process by which they manage to find a specific clip of something that happened decades ago. In my example, do they have to go through everything that guy ever said on TV to know if he said something related to the current topic? Is everything transcribed? How is the actual search process? | Technology | explainlikeimfive | {
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"Most major news organizations have vast archives of video clips of broadcasts/major news events that companies can subscribe to and go through to grab clips from. And in the case of cable shows like The Daily Show/The Colbert Report their parent company Viacom owns a news agency directly so they probably don't have to pay for the subscription rights to use the clips.",
"Meta-data is King! This depends on the database in question, but media like this will be sorted and catagorized in a dozen ways to facilitate searching. In your example, the clips shown were likely tagged with the date, original place/show they were taped, name of the speaker, type of speaking (interview, speech, conversation, etc), a handful of keywords describing the content of the talking, etcetcetc. Managers of these kinds of databases need to strike a balance between producing all this metadata for every clip they're saving vs providing enough that the media can be found. There are very well paying jobs in the data-management field to organize, maintain, and reorganize this kind of data.",
"Their own archives if they were around that long. Otherwise, they can get them from colleges, libraries, possibly even museums. Really anywhere that would have a huge archive of past records.",
"I used to work for the Daily Show as an intern. When I was there--and I'm assuming even now--they had an extensive archive that pretty much included every single second of broadcast and cable news since at some point, I believe in the late 1990s. They also have interns log portions of it (I know, I did it) and put it into a searchable system. As for broadcast/cable networks, they have extensive archive systems. Sometimes they include searchable closed captions. Othertimes, not. When in doubt, a good online/Nexis search of news articles can help pinpoint around the time some comments were made."
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errq6m | Why do the latest Playstation and Xbox consoles always release close to each other? | Especially in the last 2 generations: Xbox 360: 22 Nov 2005, PS3: 11 Nov 2005 Xbox One: 22 Nov 2013, PS4: 15 Nov 2013 and of course, the new Xbox Series X and PS5 are also going to release later this year, most likely. But why? Is there something preventing either of them from releasing their product say, a year before the other? | Technology | explainlikeimfive | {
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"The attention gathered from the constant console wars will surely boost sales. Get people talking, get them debating (or in console wars case, get them insulting and fighting) and then boom.. ..stonks for days",
"Big risk of losing out on market share if one company delays. Nintendo are different as all the Mario, Zelda and Pokemon licences are exclusive to them so they can come in a couple of years after and still be successful.",
"i would say it's because of competition. If the rval compony releases a new console with better technology, the other on has to do so too because if they dont keep up they will loose stock because of sales.",
"The ps3 actually came out a year later than the 360 but that is mainly because they had manufacturing issues that made them delay the launch. The intention was to launch along the 360. That scenario shows why they release around the same time though. The 360 had a whole year to itself and it amassed quite a lead in terms of sales and worth while games which gave it an advantage that lasted that whole generation just about. When the ps3 finally did launch it looked terrible in comparison to the 360 for many reasons. Much higher, price few good games, waiting a year for hardware that didn't really outclass the 360 and so forth. Unless you have some ace up your sleeves like much better hardware or something you are basically just giving the competition a head start. Nintendo is the exception only because they target a different audience though. Sony and Microsoft are going after the same exact demographic."
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ervyt6 | why are electric vehicles EV better for the environment than gas combustion engines GCE? | My professor asked if they’re really better, then he rhetorically asked if we knew how the batteries were made. | Technology | explainlikeimfive | {
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"A few things: * The efficiency of the fuel-to-mileage is much higher because power plants get efficiencies of scale, and electric driving provides for regenerative breaking. * The batteries themselves are surprisingly toxic to manufacture due to initial material mining and refining. However, the core materials can be recycled almost indefinitely. And as long as they are well-designed, they may last longer than the life of the vehicle itself. * They allow the use of (and improved financial viability of) environmentally-friendly power sources such as wind, hydro, and nuclear. * Even if a dirty power source is used, it allows the power generation to be moved outside of highly-populated areas. So you can have a coal power plant in a rural area hundreds of miles away from rush-hour traffic. This reduces the number of people exposed to, and the severity of, particulate pollution which is responsible for smog, asthma exacerbations, etc.",
"Bunch of weird replies in this thread. Without knowing context your professor is asking you to think a bit critically about something. So first, define \"better.\" Because things like price, carbon footprint, pollution, etc are all different metrics to evaluate over the lifetime of the vehicle. Second, when evaluating any of those metrics you need to account not just for the vehicle itself but the entire supply chain and and manufacturing. For example, carbon costs. It takes a lot of energy to make a battery, they're heavy and take energy to move the raw materials, move the finished product, put it in the car, and charge it. Where does that energy come from, and is it clean? The answer is \"it depends.\" It's worth knowing though that depending on what car you're talking about and which manufacturer, many of them account for carbon costs in the supply chain and seek to make them carbon neutral before the car ever gets to you. It wasn't always this way, and if your professor is being a jackass contrarian that thinks \"ICEs are better for the environment than EVs\" he's uninformed or a reductionist, as EVs over their lifetime are either currently or on the path towards being carbon neutral while ICEs never will be.",
"“Better for the environment” is a very broad statement, as is the term “EV”. I’ll assume you’re mostly talking about BEVs (Battery Electric Vehicles). Three categories that are useful to break this down into include: *1) Carbon / Green House Gas emissions* Vehicles generally contribute to our carbon footprint in two ways: production (carbon emitted building the car, and shipping it to its destination for sale) and operation (carbon emitted while driving it). BEVs generally produce fewer carbon emissions during production and delivery, but not necessarily by a lot. Mostly this is because the companies producing the most successful EVs are putting a focus on renewable energy sources for their production lines, and use of “green” materials where possible. Overall though, there isn’t a massive innate difference here between an ICE vehicle and a BEV. However it’s worth noting that increased use of BEVs themselves in the production of vehicles can reduce the carbon footprint of the manufacturing process. For example, using BEV semis to deliver parts (and vehicles themselves) can reduce the carbon emitted for each car produced. The second part, operation, is where BEVs shine. Unlike a petrol or diesel engine, driving an electric car emits no carbon (or other material byproducts) at all. However, in order to drive a BEV, you have to charge the battery. This is where the accounting gets a little tricky. Depending where (and sometimes when) you charge the battery, the energy may have been produced a variety of different ways. Some of those energy production methods are completely “green”, some are relatively “green” and produce no Green House Gasses (but may have other environmental concerns - like hydroelectric dams), and some are nearly as bad about pollution as operating an ICE vehicle. You can look at this a number of ways. If you live, say, in Seattle as I do - virtually all of our electricity comes from emissions-free renewable sources (hydro being the largest component), and a good chunk is completely green (wind, solar). But if you live in Texas or much of California, your power supply includes an awful lot of coal or oil-burning plants, which do emit carbon dioxide and other pollutants. Of course, producing and refining petrol or diesel requires energy, as well as processes which have non-zero emissions. These are often overlooked factors in the emissions cost of ICE vehicles. One more relevant factor that often gets overlooked are the emissions produced transporting energy. For electricity, these are virtually zero. However, for petrol and diesel, a great deal of those same fuels are burned delivering those fuels to gas stations, and further (though lesser) energy is used operating the stations. So overall, are BEVs a win in the battle for climate change? Yes! The math is pretty clear, in every circumstance a BEV will contribute less to global warming, and at an individual level the improvement vs an ICE vehicle can range from smaller to huge, depending where you live/charge. For most electric cars (Tesla, Leaf, Bolt, etc) it is always a win, though. What’s more, they continually become greener as our power plants transition to cleaner energy production. *2) Renewable energy sources* Oil is a scarce, generally unreplenishable resource, with a an ever-decreasing amount present on Earth. This is a separate issue from GHG emissions, but the math is basically the same for power sources. It’s worth noting that batteries (and to a lesser extent, electric motors) are made up of various naturally produced materials including sometimes rare earth metals. However, these materials are generally not consumed, but rather make up the construction of the vehicle - and thus can at least potentially be recycled. *3) Other environmental impacts* This is where BEVs often receive criticism. In short, producing batteries typically requires mining materials - often some combination of lithium, cobalt, nickel, manganese, or others. Mining processes vary, but mining in general is rarely a “green” activity, and lithium mining in particular has been criticized for contamination of nearby land and water. While these are valid concerns, they’re usually overblown by the anti-BEV contingent (many of whom support other more problematic resource extraction techniques, including oil drilling and hydrologic fracturing / “fracking”). Of course, oil drilling (especially offshore) and transportation of oil (e.g. tankers) are well-known for incidents with very extreme environmental damage, so even the worst case of potential ill effects from lithium mining are almost certainly lesser than the actually observed ill effects from oil production and delivery. Ultimately, there is never going to be a perfect solution, and even if better solutions come along eventually, BEVs are the best one we have today. The most pressing *global* environmental concern we have is climate change due to Green House Gas emissions, and BEVs provide a path to massively reducing those emissions.",
"One major advantage of EVs is that their power is independent of the source of that power. You could generate the electricity through coal, gas, nuclear, wind, hamster, it doesn't matter. If we crack cold fusion tomorrow, you can power your EV fleet with it. Whether EVs generate more carbon right now is irrelevant. We're getting better at renewable energy all the time, and we need a fleet of cars that can accept that energy.",
"So as others have said, the greater efficiency of fossil fuel using power plants is an advantage. EV will become better as the grid itself also becomes more green, i.e. more solar, wind, and nuclear. Currently EV isn't ideal for long-range driving since it takes a considerable amount of time to recharge compared to how quick refueling gas is. But rapid charge tech is improving, batteries can be recycled, and even if people complain about the \"chemicals\" in batteries, those are conveniently contained in a shell and not just being emitted into the air.",
"Your professor seem pretty bias. Batteries are polluant, but so is anything human do in life. The point is that the impact of fossil fuel is far bigger than the impact from extracting the dangerous material needed for batteries. On top of that, the technology of batteries improve over time, while fossile fuel will stay as polluant and the thermal engine is a very mature technology and so the hope for big improvement of efficiency is rather low. Edit : I'll just add, that EV batteries have a pretty long life up to a decade, before the charge they can hold aren't really up to the task anymore. You can still use them, but your range isn't as high anymore. That said, they are still pretty usefull batteries and a market could easily (and should) develop for old EV batteries for other use as stationnary storage."
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es36b3 | why depth of field effect in video games is not used to increase game performance by rendering the out of focus parts at lower resolution? | Technology | explainlikeimfive | {
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"Blurring parts of the image is actually going to be even more demanding on the graphics card. Instead most games DO in fact switch to lower quality versions of objects and terrain at long distances since they're too small and too few pixels to notice. In some games it's actually quite noticeable when they instantly transition between low and high quality versions. They just don't bother to try hiding it, or if they do they use something simpler like a fog effect.",
"You're equating the out of focus bits with a loss of information. Which, in our case, is true in a sortof way. At least by the time light hits our iris. Because the light that hits our retinas is missing, incomplete or disorganized. The light given off by the _thing_ in the distance is being given off whether or not our retinas were observing it. HOWEVER, preemptively cutting out some of the resolution doesn't help the computer because it has to have ALL of the knowledge about the thing in the distance in order to render it at all. Game engines can do somethings to help tho. Graphics cards are designed to do one thing very fery fast - render triangles with various textures and lighting effects. The more triangles they have to render with more textures, the slower they go. So - the game engine can cull out the triangles for things that are hidden from view. Why show the backside of a mountain when you can only see the front? The game engine has to know about the backside, but it only tells the graphics card to render it if it knows it can be seen. - far away things get lower resolution models and textures; so a bit along the lines of what you mean. Instead of rendering a whole model of a dude down to each hair, its a stick figure. Instead of a sparkly sequened tunic, its a solid purple color. But the game engine still has to know the high detail things and it has to conciously swap in higher models and textures if your viewpoint shifts. But this isn't a depth of field or optical effect, the game engine deliberately has to know what your field of view is set to vs. geometry of the world, models. etc. and make appropriate substitutions. Trees in open games, or the crowds in sports games are like this. Trees far off are usually low popsickel sticks or 2d bitmaps with perhaps some weather animation...but zoom in and you see a whole trunk, branches etc.",
"Think of rendering a frame as building a house. You build up the foundation then the load bearing walls, then windows, and the roof. DoF is what's called a post process effect. It gets added after the frame is mostly drawn. It would be like the roof of the house. The roof needs the rest of the house built first in order to function properly as a roof. Otherwise it's just a bunch of lumber and shingles laying on the ground. The Dof effect needs to know the color and the depth of the pixels it's blurring in order to blur them properly. It can't do that without rendering most of the scene first."
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es3p6l | What actually happens when an album is "mastered"? | Technology | explainlikeimfive | {
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"Mixing is making instruments sound good together. Mastering is making songs sound good together. And sound good on different systems (radio, headphones, low quality speakers). As for the tools used, it's also EQs, limiters, compressors, etc.",
"It's basically taking the \"finished\" track and polishing it to sound the best it can in the format it is presented. In the age of LPs, a big part of it was compression and EQing to make the tracks feel like they were at the correct volume and tone relative to the others on the album, and sounded relatively good whether played on a home HiFi or over the radio and out of your car. Whereas mixing is done by adjusting each track/instrument somewhat individually, mastering is almost always done to the complete final mix. So mostly just a bit of polish and adjustment to make sure the album sounds clean, even, and professional, while arranging the songs in their final order. A guitar is an instrument to a guitarist, a recording of a guitar is an instrument to a mixing engineer, and a recording of a complete song is an instrument to a mastering engineer, simply put. Nowadays, with the age of independent home producers, small studios, EPs and single releases, it is often also used to mean, \"have a more experienced professional go over the mix and clean it up, boost it's \"presence\" or \"punch\" and get rid of dissonance and mud or whathaveyou (things that professional mixing engineers traditionally do themselves), or simply \"put a plug-in on it that makes the drums hit harder and the bass rumble deeper.\""
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es4dwk | How did the Greeks measure the circumference of the earth? | Technology | explainlikeimfive | {
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"To quote Dr Farnsworth \"I'm afraid we will have to use.... MATH!\" Eratosthenes stuck a pole in the ground during the summer solstice (when the sun is directly over head). It was known that at the equator during the solstice the sun was directly over head so a pole in the ground would generate no shadow. Where as at his location the pole would in fact make a shadow. Using the shadow generated by the pole he then measured the position of the Sun as being 7 degrees different than at the equator (where the sun is directly over head). Since the distance between the two locations was known, and 7 degrees is roughly 1/50 the circumference of a circle, he concluded the Earth was about 50 times the distance of those two points round. And you know what? He wasn't that far off."
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es781s | What is data mining and how is it being used? | Technology | explainlikeimfive | {
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"Data mining is when someone tries to find answers to questions by looking at a whole bunch of information and finding patterns or interesting facts. This is really hard work which makes it expensive. So most data mining is done to make money, or for police work, or spying. The information used in data mining is almost any source you can imagine. Court records, white pages, credit card purchases, phone calls, military history, pictures, your location, Facebook, Twitter, and so on. This information can be collected and then used to figure out additional information about who your friends and family are. Your religion, your health, your race, your politics, and so on. The companies that collect this information sell that information to other companies who make decisions about you. Should they sell you health insurance, should they offer you a job, would you be likely to donate to a political party, are you trustworthy, should you be given a credit card, should you be charged a high or low interest rate, should you be allowed a house mortgage? It is also used to [target you with ads]( URL_0 ). The problem is that you have no way of knowing what information is being collected about you. You cant tell if it's accurate and you can't tell who is using it."
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esalz3 | As computers have both a microphone and speakers, how does it avoid triggering a feedback loop when both are in use? | Technology | explainlikeimfive | {
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"Firstly, they put the microphones a reasonable distance from the speakers. And, secondly, they use various techniques to reduce this feedback. Sometimes they design directional microphones, but they require space that phone and computer designs can't provide. But they can include two microphones, and sound coming from different locations will arrive at different times. Often they assume that the microphone will pick up audio from the speakers, so they just subtract the signals sent from the speakers from the sound picked up by the microphones.",
"Everyone is making this way more complicated than it really is. Remember that this was a problem way back with old timey candlestick and rotary telephones well before the invention of computers, fancy directional microphones, or any kind of digital processing. They had this solved pretty solidly by even the 1950s. There is a kind of simple audio circuit called an echo suppressor. It simply listens to the signal traveling one way on an analog circuit and subtracts it from the signal traveling in the opposite direction. In this way, the sound waves coming from the speaker can be removed from the sound going into the microphone, while leaving the rest of the sound intact. This was usually done by the telephone company on their end, because they held open the full circuit loop on their switches and so knew the exact timing delay to look for. This could all be done physically in analog, and required no special software analysis. Now that almost all voice communication occurs digitally, this can be done in software a lot more effectively. But the general concept is still the same.",
"Because the sound being recorded through the microphone is not played back through the speakers. It's not like a microphone connected to a PA system a band might use.",
"Go into the mountain, say \"EEECHOOO\", the mountain will respond with \"eeechooo\". Notice it is a little bit late and a lot less loud. Now say \"POTATOOOO\" and the mountain respond with \"potatoooo\" notice it is exactly as late and exactly as quiet as for the previous one, just with the different sound? Well, the computer try to predict how much of what it emit comes back and when, and subtracts it. This cancel out feedback loop, and echo, and sometimes even reverb (aka. no cathedral effect if you are in a cathedral). It does not like if you move the speaker and/or mike around, as it assume the response don't change too much.",
"I know this mostly focusing on Skype and VOIP calls but I can tell you that opening my MacBook into GarageBand to record some vocals and if the internal mic is on it will definitely feedback. The app will send that and ask if you’d like to turn on “Reject Feedback”. Most of the VOIP apps have a similar technique built in and always on."
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esbsyp | Why do some game need restarting after changing graphic/display settings and others dont? | Technology | explainlikeimfive | {
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"Some games are like pizzas. If you want more or less stuff on it, that's simple, just take them out or add new stuff. But if at the middle of making the pizza the customer says \"to be honest, I would have preferred a pizza twice as big\". That demand is very difficult to answer without restarting the pizza from the start. Some games are like soup. Want more soup? Just put the soup into a bigger cup and add more ingredients to it. No need to start from zero. In the end, it depends on how the program is build and how complex the program is. Moreover, debugging issued that come from allowing the user to change all the settings at any moment can be VERY lengthy, and time is very precious in game development, so maybe focussing on debugging the remaining of the game is more important, right?",
"Some games use different resolution models for all the objects in the scene for each different display resolution, so they need to swap out everything they loaded for the previous resolution. Easier to just restart. Other games have more variable resolution object models.",
"Actually, almost no game need to restart to change the graphic settings, but most games are written without expecting it to change and have lasting visual side effects. Typically, text font, level of detail of geometries, texture resolution are choices made at initialization. Then you load the one you need, and go on with the rest of the game. If you change the graphic settings it will work, it's just that those decisions won't be remade until you restart, thus temporarily playing with sub optimal visuals. As a game developer you can put that initialization into a re-initialization routine... or you can simply restart the game. It's better to spend development time on improving the quality of the gameplay rather than optimizing resolution change, which does not happen often.",
"Some games simply load higher quality assets in, for example an older game using a texture for a rifle will use the same mesh but may just load an image of the rifle in a low resolution or a higher resolution. This won't require a restart. Newer games will calculate a higher quality asset, if you have a rifle the game will use different meshes, lighting effects, and various types of graphical effects along with the higher quality texture to make the rifle more realistic. The game must reload because every piece of light on our screen must be recalculated and then redrawn including the environment which shines artifical light sources (sun, lamp, water reflection etc) onto our rifle.",
"Most games use a ton of rendering passes that depend on the screen size. Some settings, like resolution and rendering API, require the whole rendering pipeline to be discarded and created again, or even the GPU device representation to be created another way. If the engine is complex, it might be easier to restart. Now like you're 5: Imagine a game's graphics engine as a room with multiple whiteboards. You draw on one, take pics of it, erase it, draw again, use a second one to draw something else, etc. In the end, you will need most whiteboards to fit your screen. If you want to draw at a higher quality, then fine, erase it all and draw better. But if you change your screen size, you will need to change all your whiteboards so if you're managing 100+ whiteboards it might be easier to just destroy the whole room and start over. Not to mention switching to chalk blackboards. Sauce: I'm a graphics programmer",
"It's sort of like tuning or replacing parts of a car engine while it's running vs when it's stopped. 99% of the time it's just not worth it trying to mess with a running engine if you can simply stop and restart it. The reason some games even do that is a side effect from how modern games manage the loading of models/textures/shaders/animations etc. If older games had a very simple approach where everything you might need in the current level would have been loaded into memory in advance at the start of the level, modern games use an on-demand or \"streaming\" approach, where the resources are loaded in the background just before they are needed depending on where you are in the game world and similarly unloaded if they are no longer needed. This is very difficult to get right so there are no obvious visual glitches, stutter or \"pop-ins\" but it became necessary because most games these days are some sort of open world (which is a fancy way of saying they have one huge level instead of multiple smaller ones) and it wouldn't fit into memory it you tried to use the old simple approach of loading everything at once. But once you have a mechanism for loading/unloading stuff on the fly, changing settings on the fly (which typically involves switching to a different set of textures/models/shaders) becomes (almost) a free bonus.",
"Realistically, nothing that games do absolutely requires a restart. Even the code that sets up the window displaying the game can be thrown out and remade as needed. But all of that flexibility to change stuff quickly and easily on the end user's side comes with design and cost implications for the developer. Take a car, for example. They are incredibly complex machines with tens of thousands of individual components, require special tools to assemble and take apart, and if you ever need to change or replace something after it leaves the factory, you can expect it'll take some time, energy and tools to do said replacement. A car COULD be designed to be completely tooless, or have fewer individual pieces, so that it becomes very easy for the end user to go in and pop out parts and replace them whenever they want, quickly, easily and without specialized tools. However that requires a significantly higher amount of design time, and creation cost to the maker of the car, and often that extra work either goes underutilized, or is so high it makes them have to charge more. So the designers figure out what level of work they're willing to put in for those people that DO plan to swap parts of the car out compared to the people that will rarely if ever do it, and balance it against how many man-hours and how much money it'll take to do those user-friendly tooless designs. Some designers make it incredibly easy, and some just don't care and tell the end user to suck it up. Designing a similar level of flexibility/ease of use for the end user of a game or game engine is metaphorically the same."
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esiqrb | Why broadcast cameras are still so huge after all these years of technological advancement. | Technology | explainlikeimfive | {
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"[This vid]( URL_0 ) came out recently on just this topic.",
"It's not the cameras, but the lenses. Cameras nowadays are pretty small, yet the lenses required for broadcast level work need to have such capacities that make them pretty much as big as telescopes. They need to have huge working ranges for zooming and focusing so you need multiple glass elements with big spaces to move them inside the assembly.",
"Same reason that astronomical telescopes still so big. The larger your lens, the better (potential) image quality. Larger lenses require longer focal lengths, which means longer and wider telescopes/cameras. Lens size/length also comes into play if you want a lot of \"zoom\" power. This isn't a huge deal for most studio work, but is definitely an issue for things like sporting events where the camera might want to fill the entire screen with a face that's 100+ meters away. There's a similar phenomenon for image sensors--the \"film\" in digital cameras: the larger they are, the better quality/resolution. Lens size greatly outweighs this for any given camera, however.",
"Worked in broadcasting / recording for awhile. The long and short of it is they have every possible option you can imagine, and two of every possible connection. In the group I was with... For the most most important topics that we cannot afford to compromise we had a field camera twice as big as the others. It had a backup of every component (you could literally rebuild a second working camera although it wouldn't have the none-essential casing etc), and each of those components could be swapped out very easily; some of them even while the camera was running. The cost of that thing made me afraid to touch it, but it saved the companies butt more than a few times. This mic or whatever thing doesn't work and we don't have time to figure it out? We get out that brick, get any good mic/thing on any connection and we were good to go in under a minute."
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esjpgi | how do noise cancelling headphones make loud sounds less damaging without actually blocking the sound physically? | Technology | explainlikeimfive | {
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"You ever been swimming and create a wave that moves toward your friend, but your friend made a wave that headed towards you, and they just kinda met in the middle but neither of you really got splashed? Sound is a wave which travels through a medium. Noise cancelling headphones calculate the audio wave that comes in and creates a wave to counter it, significantly reducing the amount of initial wave that reaches you.",
"Sound travels in waves and noise cancelling headphones mirror the wave a sound makes, so both the original sound wave and the opposite/inverse wave (generated by the headphones) collide before entering your eardrum. Where the peak of the loud sound is a high point of the wave, the inverse wave is offset, so it's sending the low part of the generated wave at the same time, which results in very little sound vibration. Imagine a 5 foot wave coming in from the ocean. If you could somehow send a negative wave 5 feet deep towards it, they would basically cancel each other out. That's what's happening inside the headphones."
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eskgsy | Is making glass just as easy as heating up sand and that’s it? | Technology | explainlikeimfive | {
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"No, for one it has to be a fairly pure type of sand, additionally you generally need to add something that makes the sand have a lower melting point such as sodium or potassium carbonate. In general it is actually a really complicated and difficult process, if you want some more insight into to process I'd suggest looking at the failed attempts by how to make everything on YouTube. I've forgotten a lot about the process but I'm sure those videos will highlight more difficulties than I remember."
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esnnq2 | LED. Fog lights, flood lights, spot lights, car lights. What’s the difference if they all produced the same lumens? | Technology | explainlikeimfive | {
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"Mainly distance and beam pattern. Your fog lights can be just as bright but generally are angled lower and meant to for short range, but have a very uniform pattern. Mostly your low beams (though high beams as well) are to reach longer distances with a distinct hot spot/higher concentration of light in the middle, to illuminate down the road while they generally taper on the sides to prevent glare and sensory over load, but they're to illuminate enough so you can see around curves and the sides of the road for things like pedestrians and deer. You can have the same amount of lumens or even more, but if you aren't getting illumination where you need, then brightness really doesn't help you."
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essm0k | How is it possible to make only emergency calls when you have no signal on your phone? | Technology | explainlikeimfive | {
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"Your cell phone most likely has the physical capability to connect and communicate on cellular networks other than the one you are subscribed to. In normal situations, those towers don't want to talk to a non-customer. However in an emergency situation, they are legally required to accept an emergency call from any cell phone physically capable of communicating with that tower, even if it isn't a phone of a paying customer."
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esujqh | What causes the color fluctuation in older (90’s) videos? (Link inside) | So I was browsing YouTube and came across an older video and noticed the color fluctuating a lot. What causes this? [Link]( URL_0 ) | Technology | explainlikeimfive | {
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"Image is stored in VHS tapes not as a bunch of red green and blue pixels, but as analog luminance and chrominance. By now you must have read somewhere about how there are other ways to represent color. Chrominance would be Hue and Saturation, luminance would be the Value or Brightness in a HSV system. Since everything in a VHS tape is analog, the VHS player needs analog circuitry to amplify the signals. Amplifiers such as that have a parameter called gain, which refers to by how much they increase the level (e.g: from 0.001mv to 1v the gain is 1000x). There are many forms of automatic gain control, which operate on feedback loops. E.g: if the output is too high, it will decrease the gain, if it's too low it increases. That fluctuation is the VHS player's automatic gain control doing its job on a noisy signal. Notice how in the video you posted the guy's grey shirt remains kind of the same, but the background and his face changes color. What you're seeing is the automatic gain control for the hue component trying to get it right.",
"This is from degradation of a VHS tape (and/or a bad reader head). The tape holds the image data line by line and refreshes it super quickly, but if it's off a little bit then you'll see this little rainbow popping up as colors get shifting away into noise.",
"All TV used to be an analog signal - all the picture information was stored in the fluctuation of a single wave. Black and white TV encodes the picture as simply the magnitude of the signal increasing for bright parts, lower for dark parts. When color TV was introduced, they needed a system which would keep this working for older TVs so B & W sets didn't suddenly stop working, and also let them add color information. For this reason, the color is encoded as a high frequency signal overlaid on the picture brightness. The amount (\"saturation\") of the color is encoded in the magnitude of the high frequency signal, and the actual color (\"hue\") is the phase of the high frequency signal measured relative to a reference signal (the color burst) which is hidden in part of the TV signal timed so that it isn't drawn on screen. See Structure of a video signal ( [ URL_1 ]( URL_0 ) ) for more on this VHS stores that entire analog signal on magnetic tape, which does two things. The high frequency parts tend to lose strength slightly - if this was an audio signal, it would be the equivalent of high notes becoming quieter which would make the whole thing sound \"muffled\", but on VHS is translates as lower intensity color. The tape can also stretch slightly, which doesn't affect the picture much but can change the timing enough that the color signal goes out of sync with the reference, which results in the colors on screen shifting to different hues. If the tape stretches further, the signal gets out of time enough that you start to see the picture skewing sideways across the screen."
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et2v44 | How in the world do gps applications (like google maps) have all the street names? | Technology | explainlikeimfive | {
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"Basically yeah, someone input all the street names and locations. Although, the GPS companies and google maps will have it mostly automated, but most countries have large government departments dedicated to mapping out the streets, land sections, assigning postal and residential addresses etc They then commonly sell that information to other government departments to use, to private companies such as google, garmin, whoever needs mapping. Mapping and software for it is a huge industry worldwide employment hundreds of thousands of people. Just the license on the mapping software my company uses, and the infrastructure for it costs a few hundred thousand dollars per year, not counting support costs and wages.",
"It sounds like a big job, but with enough man power and time, it can be done. For example, New York has 214 streets facing east-west. These streets are easy because they are numbered, but let's pretend they have unique names. These names would already exist in a paper map, but let's pretend those are not available. In an 8 hour shift, you could probably walk (it would even take less time if you go by car) across all these streets and list their names. On the next day, you could walk the other way list on the north-south streets. On the third day, you could transfer the data to the map. In three days, a single person could name all the streets in New York. If a staff of 100 people did this every day for one year, they could map 12,000 cities the size of New York per year. If they have been working since 1990, that one team could have mapped 365,000 cities. If multiple teams combine their efforts, lets's say a dozen teams per country, then it wouldn't take that long to map the whole world. Again, most of this work was already done many years ago on paper maps, the teams wouldn't even need to leave the office to figure this out."
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et3w5r | When DVD first came out I remember watching them and thinking how amazing the quality of the picture was. Now if I watch an old DVD I find it so hard to watch because it just looks so bad. Why is that? | Technology | explainlikeimfive | {
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"One thing people are not mentioning is that we used to watch dvds on tiny low res TVs - now we watch them blown up on huge HD displays and the faults are evident.",
"Because what we consider \"normal\" changes over time. Someday people will look back at 4K video and think, \"how quaint and crude it was in their day\" I'm sure.",
"What you're exposed to. You were used to (let's say) 144p and you see 360p it looks amazing. Furthermore the move to HD technology has spoiled us so previous comparisons look bad. Video games have this even worse where people (including me) can remember something being vivid and clear, but upon future inspection was a blurry mess of polygons. It's all about what you see now vs what you had to compare it to then",
"The DVD is like a girl from your home town... You think she's hot then you move to a big city, exposed to many, many beautiful women. You go back home for Christmas and see her as a cashier at the local grocery store, and think to yourself, \"how did I ever think she was hot?\""
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et8ven | How does 3D modeling work in video games? | I know from a very basic standpoint that game devs create a model for a character/object, but how exactly do they keep consistency? Do they use that same exact model for all cutscenes, different angles, different depth distances etc? As in if a model of a character was a mile away, could you theoretically walk all the way up to that model and it would be the same perspective as if you were walking up to a real person/object? Or say for instance you had a camera shot from the foot of a character model looking up at them, is that the same model used for every other shot to keep consistency? Sorry if I’m making no sense here lmao this has just been bugging me | Technology | explainlikeimfive | {
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"You could use the same model in all of those cases. But for performance reasons most games don't. It doesn't matter what angle you're looking at the character. That's the point of 3D models, you can look at them from any angle. Unlike 2D sprites where you needed separate images for different angles. But there's not much point in using a highly detailed model when it's too far away to see that detail. So games usually use a model with a lower Level Of Detail (aka LOD), which gets switched out for one with more detail when you get closer. In some games you can see that happening if you look closely enough when moving towards something. They might do a similar thing for cutscenes, where a model with higher detail is used for cutscenes particularly when there's a close up of the face.",
"3d modelling for games and other media are essentially the same. The basic principles are: A wireframe: This is the boundaries of your object. Wireframes are made up of vertices, in general, the more you have, the \"smoother\" an object will look. However, the more there are, the more computational power is needed. This would be the outline of all of the distinct faces on a house. Textures: These \"paint\" material over the wireframe. As the detail in the texture increases (or its complexity) the more computational power is needed. These would be wallpaper, flooring, etc. There are lot of tricks, like bump maps, but they aren't necessarily worth digging too far in to. Lighting is self explanatory. Viewports are like cameras, it's your perspective viewing a scene with one or many models, light sources etc. Only what can be seen in the viewport is rendered, so for example, if you're looking at a house, the back of the house, and its interior are not rendered, if you cannot see them. Because an object far away (relative to the viewport) will not need a lot of detail, you can get away with using fewer vertices, and less detailed textures. So essentially it's the same model, just with less detail. Using the house as an example, you don't need to individually render shingles on a roof if you're far away, but as you get close you may need to, and even closer you may need better textures to show grain. Depending on the cut scene, you may use different models (and processes) entirely, especially if you can't interact with it, because you know exactly what the viewport will be. But you could also use a super detailed version of the same model.",
"There's a few things they do to make this work. Mainly, LOD (Level of Detail), meaning they make a nice high detail model for close up shots, then simplify that model a few times, reducing it's complexity, and swap it in and out on the fly. Psyk60 pointed out you can sometimes see this in games. Other tricks that aren't really modelling, but semi-related, are normal and displacement maps. Normal maps affect how light reflects off the model, and they can use that to simulate higher detail than there actually is.Displacement maps can affect the geometry itself (maybe DX12 tessellation, I'm absolutely guessing here) or just displace the pixel, which looks nice, just has some limitations and performance improvements. I'm no expert, that's all based on my limited Blender knowledge and interest in the area :) EDIT: I pointed out the normal/displacement maps because sometimes you could get away with not having a different model, and just having fancy maps, but usually a combination of both since simple models are easy to spot (old games with pointy faces, etc)"
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et8yyp | Why does compressing an image or GIF create noise in previously-solid areas? Surely that requires MORE information to be stored? | Technology | explainlikeimfive | {
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"GIFs aren't really designed for photos. The noise added is because of the conversion to 256 colours. And you're right. It does often require more information be stored. The format is best for hand drawn images. JPEG is a little different. It doesn't store pixels directly. It stores 8x8 squares, made up of patterns [like these]( URL_0 ) added together. Generally real world images only need a few of them and the least important ones are removed to keep the image size down, but because most of them look like noise.",
"GIFs are limited to 256 colours. This was a common thing back in the day to save space and because many PC monitors ran in 8 bit colour mode - start with a table of colours (called the palette) then each pixel is only a single byte even before you compressed it. Many image formats were palette based or at least supported it. But if your source image has more colours than 256 then you have a problem. Standard solution method is called dithering, where you replace a solid chunk of a colour which isn't available with a mixture of colours you do. This results in the noise. If you see a dark brown with slightly light brown noise, then the original colour was actually darkish brown slightly lighter than the main colour. Suffice to say, Gif is a bad choice for photo-realistic images. The good news is gifs are mostly phased out from the internet. Their only real advantage is both transparency and animation in the same image, but with web videos covering animation needs these days gif is dying."
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etc1wy | Why do video game discs need to install while cartridges don't? | Technology | explainlikeimfive | {
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"The access time of a CD is, compared to flash ROM memory (the cartridge) actually very slow. And much slower than hard drive. And modern game access requires multiple accesses to multiple files in perhaps a non sequential order, so reducing the # of read operations, or moving them off the CD is ideal. Also, games on CD themselves are still highly compressed. Since CDs cannot be written to, the file that needs to be decompressed has to be copied off and extracted on harddrive. ROM based cartridge games however were so small and compact, the entire level, all of the graphics and sprites were loaded from the cartridge at the beginning of the level.",
"Games that come on discs do not necessarily have to be installed. Old consoles like the PS1 didn't need to install games, and in fact had no internal drive to intall the game to. The main reason for which games need to be installed is speed. The disk drive is much much slower than the console internal drive, Installing the game onto the console's drive makes every IO operation faster and speeds up loading (in between level and during gameplay) significantly."
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etf8vo | How does a device, that is not connected to a network, update on its own without internet access? | Example: The Nintendo ds lite. Backstory: as a kid I had a microSD that I loaded all of my games onto to save space and keep from losing them. Years later they no longer worked and after doing research I found that the device had “updated” and I couldn’t use that microSD without reformatting it and re-downloading the games. | Technology | explainlikeimfive | {
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"Older consoles used to use the games them selves to update. If you buy a newer game and your device firmware is not compatible, the actual game cartridge would have a firmware new enough to play the game.",
"The DS Lites have their own integrated wifi, actually. URL_0"
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etfls9 | How does the 3D data in Google and Apple Maps get compiled? | Is there just one method? Is it fully automatic or does it require human supervising? Does it work the same for all types of surfaces? (e.g. Buildings, trees, hills) | Technology | explainlikeimfive | {
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"it's automatic. when the satelites orbit the earth, they fly slightly different courses on different orbits. using the difference in photos between two or 3 orbits, algorithms can infer height data. [Here's]( URL_0 ) an interesting read about it"
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etgnrf | How is a country able to “Shut off” the internet? Is there a switch? | Technology | explainlikeimfive | {
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"The government will instruct ISPs to disconnect or null route the internet coming into the nation. Basically they disconnect the fiber optics coming into the country. More likely they change the routing so that traffic coming in/out of the country gets blackhole, ie goes nowhere. They do this so that they can allow internet traffic to continue to certain places like government offices if they so desire.",
"There is actually. In most cases, the trunk lines or \"backbone\" of all telecommunication traffic, including internet, old telephone long distance and cell phone traffic is all over giant data lines. Someone has to maintain these (quite expensive, and sometimes fragile) lines, so that falls to one or two major telecom providers. These big international data lines will terminate in telecom data centers or vaults, then split and branch out to smaller lines to cover smaller geographical areas. In these data centers, there will be a few central \"core routers\", switches and firewalls to which those lines are physically connected and through which all data traffic into/out of the country will have to go. so, when you get some whackjob leader wanting to block Facebook or Imgur because of an embarrassing photo of him wearing a latex clown suit going around, sometimes it is as easy as phoning up the heads of those telecoms and saying \"shut off the internet. Now. Or you go to gulag!\" Now, in reality, many countries are connected to the rest of the world via multiple connections. So while its possible that some idiot with a backhoe who didn't call before they dug can cut internet to the entirety of Khazakstan, usually there are several connections that would have to be cut. But there will be a very short list of telecom people to call to enact a blockade. And its not like some IT wonk wanders over to a rack labelled \"Internet - DO NOT SHUT OFF\" and pulls a cord... no no, there's administrator software they do it from their desks. Walk? To the server room? Psssh. Amateur.",
"Not one switch. But the Internet is computers and connections between them (cables or wireless connections). And those computers and the connections between them can be switched off. You may have a home router, and you can switch that off to \"Shut off\" the Internet in your home."
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etj2w3 | Why are satellites put into "graveyard" orbits instead of being de-orbited entirely? | ELI5: Why are satellites put into "graveyard" orbits instead of being de-orbited entirely? [DirecTV rushes to dispose of satellite that might explode ]( URL_0 ) | Technology | explainlikeimfive | {
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"A graveyard orbit is used when the change in velocity required to perform a de-orbit maneuver is too large. De-orbiting a geostationary satellite requires about 100 times more delta-v than shifting it to a graveyard orbit.",
"Most satellites that get put into graveyard orbits are in geostationary orbit which means they're 35,786 km above the surface of the Earth and orbit once per day. They're really far away and simply don't have enough fuel to deorbit themselves. The DirectTV satellite will be going into a graveyard orbit about 100 km further out than the standard geostationary orbit, its going to be really really far from any other satellites that we care about, and any debris that it creates will be in a similar orbit and unlikely to cross into the geostationary orbit ring that we care about. So how many satellites can you shift to this graveyard orbit? Well if you space them 100 km apart you can fit around 2600 satellites into that specific graveyard orbit, but you could also park some 150 km out or 200 km out. Space is big and its really easy to hide a satellite so its unlikely to ever bother anything you care about ever again."
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etjiw8 | Why does Spacex land it's used boosters on a drone ship in the sea and not on land? Why take the risk of the booster toppling over or the whole mission getting scrubbed due to choppy seas? | Technology | explainlikeimfive | {
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"Rockets have to go stupendously fast to get their payload going, and they have to do it while tipping sideways. That means, when the Falcon stages separate, you're going sideways, away from your launch pad, at a fairly good clip. To return to the pad, Falcon would have to cancel out its sideways velocity, and then add more sideways velocity to get back, and then cancel it again for landing. It's a lot easier and simpler to just come down at sea, even though the landing is more of a technical challenge.",
"They do both land on sea and on land and at least one booster has tipped over in rough sea. The problem is that you need more fuel to reverse the direction of movement and fly back to the launch site then to continue forward and land on a drone ship. So if they have enough fuel left when they have done the burn neede to put the payload in the correct orbit the do return to land if not they land on a drone ship. For very heavy payload they do launches with no attempt to land because they do not have enough fuel. They cost more and you remove the parts of the rocket that is only needed for landing. There are no islands out at sea where they launch so you cant build a land-based landing site where the drone ship is. The launch site was built on location so you can to launch over open sea in the 1950-60 so the stages that fell back down would not hit anyone.",
"Once the booster completes it's primary mission, it is more like a guided bomb than a powered flight vehicle. There is enough fuel to slow it down to land but not enough to \"pilot\" it like a plane. (plus it has no wings) Once it starts to return to ground, there is only so much choice for a landing spot. Having the capability to land on water is also a tremendous advantage because it opens up a lot more launch locations. It also makes more sense not to risk something big and heavy and not very maneuverable going over land where the risk of hitting someone or something is a lot higher should anything go wrong.",
"It depends on what they're launching, where they're launching it to, and where they're launching it from. When the Falcon 9 launches and separates the second stage, the first stage must flip around and burn its engines to slow down to it will make a controlled reentry. If they land in the ocean then it just needs to kill most of its speed so it drops closer to straight down. If they want to land on the pad then it needs to keep enough fuel to bring itself to a full stop, then accelerate back towards the launch site pretty aggressively which requires significantly more fuel reserves than landing at sea. If they're putting a small payload into a relatively low(aka slow) orbit then they won't need to use up nearly as much fuel in the first stage, and the second stage can take care of a lot of it. This leaves them with enough fuel to return to the launch pad when they launch small satellites into Polar SSO(Sun Synchronous Orbit) or bring cargo to the ISS. If they're putting something large into orbit, or putting something into GTO(Geostationary Transfer Orbit) then they need to run the first stage out of most of its fuel to ensure they can get the satellite to its intended orbit with reserve fuel in the second stage. This means they won't have enough fuel to slow down to zero and then get back to the launch pad so they land at sea. Landing the rockets is a great cost savings for both SpaceX and the people riding those rockets, but at the end of the day the primary mission is always getting the payload into the desired orbit. If they have to lose a rocket to get the payload into orbit because of rough seas or an anomaly on the rocket, then they lose the rocket like everyone else did for decades."
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etm9et | When movie characters do that thing where they pull back the hammer on a handgun (to show the other character they're super-serious), does that mean the gun was essentially unloaded before they did that? | Technology | explainlikeimfive | {
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"**Short version**: Probably not for most guns **Long version**: Depends on the gun, how the hammer was cocked and the condition of the gun before they cocked it, but most of the time it's probably just making some threats/noise and not changing the loaded state of the gun **Very long version**: This is largely a Hollywood trope that carried over from westerns into modern depictions of firearms. Early revolvers (cowboy style guns after the age of colonial era single shot weapons) were what's called \"single action\". This means that in order to fire the gun, you first had to cock the hammer on the gun back. Pulling the trigger would release the hammer allowing it to strike the primer and fire the gun. This is where the trope would have started. Later on revolvers were designed to operate as \"double action\", meaning that pulling the trigger would both cock the hammer and release the hammer (one trigger pull does two actions, hence \"double action\"). Most such revolvers actually allow manually cocking the hammer to operate like a single action gun. The advantage of this is usually the amount of force required to pull the trigger completely is reduced. When cocked, the gun might only need 2 lbs of force to release the hammer, but in double action mode might require up to 10 lbs (or even more) of force. The less force required, the less likely you are to mess up your aim. What's important to note about a revolver is that cocking the hammer advances the cylinder to the next round, so if the gun has not been fired, cocking the hammer doesn't run the risk of \"wasting\" a round. & #x200B; Now, semi-automatic pistols (think most modern hand guns, Glocks, Sigs etc) come in two different forms, the first is hammer fired similar to a revolver in that there's a physical hammer on the back of the gun that must be cocked to fire the gun. Early semi-automatic pistols like the Colt M1911 (the standard army issue pistol from WW-I through Vietnam) were Single Action only, just like early revolvers. What makes them semi-automatic in comparison to a single action only revolver is that unlike the revolver where every hammer cock must be performed manually, only the first one had to be done by hand with the 1911. Every subsequent shot was cocked by the slide of the gun moving backwards as the round is fired. So in a movie if you see someone pulling the slide of a semi-automatic gun back, that's a similar action to cocking the hammer of a revolver. A double action semi-automatic again works similar to the double action revolver, pulling the trigger cocks and releases the hammer, and like revolvers many double action semi-automatics can be manually cocked to work like a single action semi-automatic. In fact, most double action pistols are double-action/single-action meaning that the first round can be fire with a double action pull of the trigger (and the increased pull weight we talked about with revolvers) but subsequent rounds have the hammer cocked by the slide moving back when being fired and are thus single action because the trigger now only has to release the hammer (and this comes with the reduced pull weight) Both revolvers and semi-automatic pistols come in \"double action only\" forms, where there is no way to manually cock the hammer without pulling the trigger, on these guns either the hammer is smoothed without a place to grip it to pull it back, or is entirely internal to the gun, and the slide (for semi-automatics) does not actually cock the hammer when it moves back). For the purposes of this explanation, a Glock would be an example of a \"double action only\" semi-automatic pistol (the truth for that is a bit more complicated), and a lot of modern revolvers designed for concealed carry are built like this to keep hammers from getting caught on clothes. & #x200B; But the important difference from revolvers is that slide on a semi-automatic pistol. Pulling the slide back on a semi-automatic pistol (either by hand or by firing a round) will eject the round that is currently chambered (that is, in front of the firing pin, if there is one) and load the next round into the chamber. It is necessary to pull the slide back once to chamber the first round when loading a new magazine (the box that holds the extra rounds) into a pistol. If you don't do that, the chamber is empty and cocking the hammer (without using the slide) either by hand or by pulling the trigger on a double action gun will result in no bang. So what does this mean for our super serious action hero if they cock the hammer of a semi-automatic pistol? Well if the gun had no round chambered and they pulled the slide back, it means they chambered a round and (if a DA/SA pistol) put it in single action mode. Until they pulled the slide back though, yes the gun was effectively useless for firing. If the gun had no round chambered and they just cocked the hammer without using the slide (e.g. with their thumb), then they did absolutely nothing except make a threat. If the gun had a round chambered and they pulled the slide back, they just ejected a perfectly good round from the gun and (if a DA/SA pistol) put it in single action mode. Unless it was a single-action only pistol, this was a waste of both a round and time. If it was a single-action only pistol, it was a waste of a round. If the gun had a round chambered and they cocked the hammer without using the slide then unless the gun was single-action only, it was a largely unnecessary action designed as a threat, and at best it helped improve their aim for the first shot. If it was a single-action only pistol, then no the gun was not unloaded, but it was a necessary action to prepare to fire the first shot. & #x200B; Lastly, most modern guns (revolvers and pistols alike) are likely to be either double-action only or double-action/single-action guns, meaning the cocking of the gun is mostly unnecessary and is largely either for show/threat or at best reducing the trigger weight of the first pull. So while it's mostly a Hollywood trope, it's not completely braindead. But if you see characters going around pulling their slides back over and over after chambering that first round, they are definitely wasting good ammunition and that's pure Hollywood stupidity.",
"When you bring the hammer back, it’s an easier pull of a trigger. If it’s not cocked back, the trigger is heavier.",
"The hammer exists on double action handguns. Double action refers to the trigger, part of the pull is the \"cocking\" of the hammer back, the rest of the pull (which is much lighter) is the hammer going forward, activating the firing pin, hitting the bullets primer, and shooting the bullet. Which means, for all of this to happen, there was already a bullet in the chamber. Double action handguns are ONLY double action for the first shot. The rest of the magazine (and following magazines) are single action, which is the lighter, final pull of the trigger. The mechanism itself ensures the gun stays in single action mode unless the decocker is utilized. Which pops the hammer back into place without activating the firing pin. It's mainly a movie thing. Most people that still carry Double Action/Single Action (DA/SA) handguns carry it with the hammer already back. Two different trigger pull weights just complicate things. It's used for dramatic effect. What drives me nuts is in cop shows or movies, they constantly rack the slide - which is the action of pulling it back to take a bullet from the magazine and put it into the handgun's chamber - when they kick in a door or some such shit. Why in God's name, as an on duty law enforcement officer, is there not a bullet already in your chamber? Drives me nuts. It doesn't make sense."
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etqfkh | How are phones hacked? | I understand how computers are hacked but how are phones hacked? As I would think it would be pretty difficult, for example Apple intentionally block access to the system files of the iPhone to prevent malicious activity but somehow Jeff Bezos's phone was hacked? | Technology | explainlikeimfive | {
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"Phones are just smaller computers. Most run a version of Linux/Unix and have the same flaws as other versions of those systems. In the case of Bezos, there are lots of uncertainties, but it's possible that Saudi has access to a previously unknown exploit that was used to access his phone. Just like clicking on a bad link in a email can \"hack\" your own computer.",
"I'm really curious too, I only heard whatsapp was involved, but I think usually there's a program that takes some unexpected malicious input that allows a remote user to control it and gain it's privileges. They then use those privileges to gain more privileges, create a back door (connect to a command and control server somewhere and leave the connection open so c & c can use it to login to the host) and then it's game over. Doing a little googling, it looks like in this case someone sent Jeff bezos a maliciously encoded mp4 video that when opened in whatsapp, used some bad whatsapp code (written to load the video) to instead perform a stack overflow where the attacker can change some really specific bits in the stack (memory / ram) and totally change the way the program runs to their advantage. Potentially executing their own code they might have sent along with the video. TLDR; shitty code and stack overflow attack on mp4 video loading procedure within whatsapp",
"If the media says something was \"hacked\", what they almost always mean is \"the password was guessed\". The way the News of The World \"hacked\" celebrities' voicemail was to guess their voicemail password. But, at the end of the day, the iPhone is an ARM-based computer, no different to any Android smartphone, no different to any Chromebook, myriad types of other computer (e.g. Nintendo DS or some digital cameras), and ARM is really no different (security-wise) to the Intel etc. chips. If you have something, on the Internet, accepting network packets, running code and running on an ordinary processor... it can be hacked. There's no such thing as a unhackable operating system (and iOS is especially no different to any other in that regard - Windows supposedly \"blocks access to system files\", etc. just the same... do you not remember UAC?) But whenever ANYONE who doesn't work in IT has ever said \"hacked\" to me, what they meant was \"I chose a shit password and someone found it out / guessed it\"."
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ett7xq | Why are the old 35mm film negatives I found not getting ruined in light? | Technology | explainlikeimfive | {
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"When you develop the film in a lab, you use chemicals that bring out the picture then use another chemical that fixes the image. Once the film has been developed and fixed, it's perfectly safe to shine light on it. In fact, that is how enlargements are made, by shining a light through the negative and focusing it on photographic paper that is sensitive to light. Then you have to develop the photo paper the same way (with its own set of chemicals) to bring out the image and fix it so it is no longer affected by light. I had a photographic darkroom when I was in high school and did all that stuff.",
"The film has been “processed” or “developed” and is now a negative and no longer in its light-sensitive state. (Exposed but unprocessed film doesn’t show any visible image.) The next stage would normally have been to take this (processed) negative and use an enlarger to project the negative image into light-sensitive paper to get a final positive image. (These days, processed negatives would often be scanned for digital processing rather than immediate printing.)",
"Negatives are not really the same as film. You put film in the camera, the camera exposes it to a small amount of light, then you develop it and that process turns the light sensitive film into negatives that can handle light.",
"Film only is damaged when it first is exposed to light before it is developed. Negatives are the end process."
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eu26mz | Why hacking is a recurrent problem on games like CS:GO and PUBG, while other games, such as Rocket League, have basically no hacks at all? | Technology | explainlikeimfive | {
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"Because how could a program help you play rocket league? Help you come up with strategies of where to go and what to do? You can’t hack a game where the computer can’t play as well as humans.",
"All of it comes down to the framework of the games, both how the game is made and how cheaters are detected/punished. Not sure the specifics with the games mentioned, but there will definitely be differences in how easy it is to do, as well how easy it is to avoid detection. If things are handled more on the server side, clients can't change much to their advantage."
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eu39wr | Is overcharging still something people are worried about in 2020? | Technology | explainlikeimfive | {
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"Don’t worry. Apple will do all the overcharging you could ever need— on the price of their products."
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eu61tv | How does a computer file become corrupted? | Like you have a game and everything is working fine but then after starting it up another time some files are corrupted. | Technology | explainlikeimfive | {
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"This could habe two possibilities. Crappy coding or faulty hardware. If the coding has some bug, than it can happen that while the file is being saved, some process related to it crashes. Then the file has not all of the needed content as is therefor corrupted. If the file sits in area of the harddrive that has damaged sectors, the computer can not read all of its contents and the file is then considered corrupted.",
"Imagine you’re reading a choose your own adventure book, where the end of each chapter tells you to go to the tenth page or the eleventh page depending on your choice. Now imagine something happened where a bunch of the instructions got the chapter number wrong (a coding error) or you replaced some pages before the tenth but accidentally added more than you removed, causing the tenth page to become the eleventh. The story would become increasingly hard to decipher. Based on what fragments of the story remain, someone could potentially detangle it, but if you can delete it all and just get a new copy of the book that might be simpler.",
"A file is really a really well parsed string of characters (well, binary if you go even further down). That file is constantly changing- memory address getting overrode and sometimes changed, data types being used, new structures being prototyped- all of that can easily change something it shouldnt have, or write to the wrong location. When that happens, that string is massively messed up, and the computer cant make sense of that at all."
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eu7096 | How can Apple put 8.5 billion transistors in a 10*10 millimeters chip? | Technology | explainlikeimfive | {
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"in the 50's, an engineer at Texas Instruments named Jack Kilby discovered that you could build a transistor directly onto a semiconductor surface without needing to individually build discrete parts and wire them together. This was the first integrated circuit. Fast forward a bit, and this idea was expanded so that you could essentially draw a circuit on a sheet of film, then use photographic techniques to copy the circuit design onto a semiconductor surface, leaving you with a working circuit. This technique has been revised hundreds of time since then, so that today designers can build a chip containing billions of transistors, then transfer and shrink that design onto a very tiny wafer of semiconductor.",
"Without going into too much technical detail: a lot of stuff fits into 10x10mm when your stuff is on the scale of 0.00001mm.",
"One of the key ways is by using a particular type of chemical called a \"photoresist\". It is a material that changes its properties when exposed to light. The main property that changes is its ability to be etched away by a certain type of chemical. Creating an integrated circuit (a circuit containing many transistors and other components on a single small piece of silicon) takes hundreds of steps. But a lot of the steps are similar. For example, let's say you want to create the wire \"traces\" that connect up various transistors. First you deposit a layer of metal such as Cu on the wafer. It covers the entire wafer, which has many ICs on it. But you don't want to have Cu everywhere, short circuiting it all together. So next you put down a thin layer of photoresist. Then, you shine a bright light through a \"mask\". The mask has the image of what you want to make on each IC, but it is 5 times larger. It blocks the light in places where you want to have the Cu remain on the wafer, but is transparent elsewhere. You shine this image through some lenses to reduce the size, and it hits the photoresist. In the places where it exposed (not masked off), the photoresist changes its chemical structure in a way that makes it easy to etch away with certain chemicals. After exposing each IC on the wafer in this way, you do the etching process. You etch away the photoresist in the areas where the mask was clear, but it remains in the other areas. Then you expose the wafer to something that etches Cu but that won't etch away the exposed photoresist. That photoresist acts as a physical mask, preventing the etchant from attacking the Cu. The Cu gets removed in all of the places where there is no remaining photoresist. Then you use a different etchant that will attack exposed photoresist but doesn't attack Cu. You are now left with a wafer that has the same pattern as what was on the mask, but that pattern has been created in the Cu layer on the wafer. You have wires! I've simplified the process a bit, but that's the basic idea. This is done over an over to make transistors, conductors, contacts/vias between layers of conductors, etc. It's very complex and has taken 50 years or so of continuous improvement to get to the point where we can make transistors as small as we currently can."
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],
"text_urls": [
[],
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]
} | [
"url"
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| [
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|
|
eu7ch5 | Why is the black light called "black", when it is actually blue/purple? | Technology | explainlikeimfive | {
"a_id": [
"ffm6lba"
],
"text": [
"Because it isn't *really* purple. It just bleeds into the visible spectrum at the blue end. The majority of the light given off is ultraviolet. This kind of light is invisible, with only a small amount of visible blue light coming from the bulb, giving an impression of \"black light\" UV light also causes some materials and colors to shine brightly, further solidifying the blackness outside of the brightened area. Naturally, the term \"black light\" is not a scientific thing, it's an industry term for ultraviolet light that makes it sound cooler."
],
"score": [
23
],
"text_urls": [
[]
]
} | [
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]
| [
"url"
]
|
|
eue2rt | What's the difference between all the different units to measure electricity related like, Amps, Volts, Watts, Joules and any others I missed? | Technology | explainlikeimfive | {
"a_id": [
"ffom9az"
],
"text": [
"Amps is the rate of electricity flowing, its actually a measure of the quantity (a coulomb) of electrons flowing in a second. Volts is a measure of the force pushing these electrons. Ohms is a measure of the resistance an object has to electricity flowing through it. It takes one volt to force an amp to flow through one ohm. Watts is a measure of power. Watts equals amps multiplied by volts. For comparison 1 horsepower is equivalent to 750 watts. Joules is a quantity of energy whereas watts is a rate of energy flow. 1 joule is equivalent to 1 watt for 1 second."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
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|
|
eueth9 | What does it mean for a fabric to be pre-shrunk? | Technology | explainlikeimfive | {
"a_id": [
"ffor8c3",
"ffor23r"
],
"text": [
"Some fabrics like cotton shrink in the dryer. So, some manufacturers shrink the fabric before making the apparel.",
"They basically prewashed it, so when you wash it, you dont have to worry about shrinkage. I usually buy a size larger than what I should,because my shoulders are broad, and most shirts shrink when you first wash them. This I could buy at the size down, because it won't shrink from where it's at now."
],
"score": [
4,
3
],
"text_urls": [
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]
} | [
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| [
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|
|
eumel7 | What does it mean when a gamer refers to the metas of a game or the meta in a game? | Technology | explainlikeimfive | {
"a_id": [
"ffq714u",
"ffq61x6"
],
"text": [
"“Meta” isn’t an acronym. “Meta” is stuff that is self-referential I first came across it in computing - back when I learned about HTML at the start of the web in the early 90’s (but I found out it’s older than that - see Wikipedia entry at end of comment). “Metadata” is “the data about data.” It was the information in the header of a web page (invisible to the user) but contained data about the specific web page. Obviously, “most effective tactic available” doesn’t make sense in this instance - there are no “tactics” in web page information. A meta game is “the game about the game.” It’s sort of the next level of strategy. Instead of the game statistics and the powers of different characters (say like in Dota), it’s the next left. If they pick Phantom Lancer, I’ll pick Earthshaker. It’s the game about the game, in that sense. [Link to Wikipedia entry about metadata]( URL_0 )",
"It refers to the current widely accepted “good” strategies of play. These sometimes change with patches or new gameplay techniques developed by those who play at the highest level."
],
"score": [
12,
9
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Metadata?wprov=sfti1"
],
[]
]
} | [
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| [
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|
|
eunta3 | What does bandwidth means and its use in torrents? | Hi, when I download torrents the utorrent app offers me bandwidth (small, medium, high). I assume high means it will download faster but what does that mean and why does it download faster. Also, why would I ever use the other options if this one is the fastest. In short, what does bandwidth means, why does it matter and what its use in torrents? Please and thank you. | Technology | explainlikeimfive | {
"a_id": [
"ffqdxvf"
],
"text": [
"Bandwidth can be thought of like a road that information travels along. Lets say your bandwidth has ten lanes, normally 2 of those will be for uploading and 8 for download (most people download way more than they upload). Basically your torrent program is saying “okay, we set aside these 6 lanes for torrenting, we have a set of 3, 2, and 1, which would you like to use?” The 3 lane one is going to go faster because there is more space, the 1 slowest. Thats pretty much it Why you would chose a lower one really depends what else in your house or on your computer you want using the roads (or even other torrents). Some things are less important and you’d rather use the bandwidth to play a game while it downloads or something like that."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
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| [
"url"
]
|
euqp7y | Why is IP geolocation not exact? Why does an ip tracker or ip lookup website show a place a bit distant from my street? | Technology | explainlikeimfive | {
"a_id": [
"ffqxyoq",
"ffqy607"
],
"text": [
"IP geolocation works the same way someone could guess your location from your phone number. Different area codes and prefices are assigned to different regions (or at least they use to before cell phones messed things up), and if you knew the pattern you could make a good estimate. IP addresses work the same way, ISPs control certain ranges of IP addresses, and often break them up by region. The location you are seeing could be an arbitrary point in the middle of the region that has IP addresses like yours, or it could be one of the ISPs routing junctions. Or, as is often the case, it could be completely wrong.",
"Your public IP address which geolocation uses, belongs to your ISP. So it's most likely tracing that IP address to a data center where your ISP's router is located."
],
"score": [
14,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
|
euvx7m | Why does speeding up audio raise the pitch? | Technology | explainlikeimfive | {
"a_id": [
"ffrtbl9"
],
"text": [
"Sound is a wave. The pitch is determined by the wave's frequency - how quickly it oscillates. The faster it oscillates, the higher the pitch. Speeding up the sound causes the wave to oscillate faster, so the pitch goes up."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
]
|
|
euw4nd | How does wireless battery charging work? Like for cellphones | Technology | explainlikeimfive | {
"a_id": [
"ffrudo0",
"ffs3gjy",
"ffs1riz"
],
"text": [
"Basically the charger panel is taking electricity from the wall and projecting it out at s magnetic wave. The phone the has a component that converts the magnetic field into electric current which goes back into the phone. There a lot more physics stuff to this by the way, I'm skipping over a lot for the format of this sub",
"What others are describing is summed up in an equipment called a [transformer]( URL_0 ). A primary coil that has electricity flowing in it produces an electromagnetic field. A secondary coil that is close enough to the field will have an electric current induced by the field. Wireless charging is fundamentally this. A transformer uses an iron core to efficiently transfer the EM field from primary to secondary wires, but other than that the concepts are the same.",
"Electricity and magnetism are linked together. With the right equipment you can convert one into the other. So the wireless charger turns electricity from the wall into magnetism, then the phone turns the magnetism back into electricity to charge the battery."
],
"score": [
47,
15,
12
],
"text_urls": [
[],
[
"https://i.pinimg.com/originals/44/20/b2/4420b294f25ff197e29f4d2cee65656a.jpg"
],
[]
]
} | [
"url"
]
| [
"url"
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|
|
euw9xi | How do applications use anything more then 100% CPU | I see all these applications using 350% CPU sometimes but how is that possible? | Technology | explainlikeimfive | {
"a_id": [
"ffrvo8c",
"ffrzhb2",
"ffsfvvh"
],
"text": [
"Think of a CPU as a single worker in an office. Originally most computers just had that one worker but these days modern computers are have more workers in cubicles (like modern offices). Each worker can work independently, but if a program knows how to break itself into multiple bits, it can get multiple workers to work on it at the same time. When you see 350% CPU think of it as meaning 3 and half workers are all spending their time running this programme.",
"100% means 100% of a single core. If you have a quad-core processor, the maximum possible is 400%.",
"I believe this is how macOS reports its CPU usage in comparison to windows which just sums up all the CPU cores and total out of 100% it has to do with number of cores and each cores individual utilization summed up to a total usage. The applications themselves don't use more than 100% CPU, but they can utilize more than one core making it appear like there is further utilization."
],
"score": [
19,
7,
3
],
"text_urls": [
[],
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} | [
"url"
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| [
"url"
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|
euy5hk | Why do fast chargers take so much longer to complete a full charge? | I've had several phones with fast charging. They're amazing. You can charge your phone over 60% in 40 minutes. But why do they slow down so much when it comes to bring a phone to full charge? | Technology | explainlikeimfive | {
"a_id": [
"ffs7aqt"
],
"text": [
"Basically when charging a battery electricity is forcing ions from one side of the battery to the other. When a battery is low there's lots of empty space to shove those ions and the flow over easily. When it's closer to full the space is filled up and the new ions have to crowd in around the older ions shoving them about to get tightly packed. All the shoving generates heat so at later stages of charge you need to slow down or you risk heating up the battery and damaging it."
],
"score": [
29
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
]
|
ev2q77 | why is ram so fast? | Technology | explainlikeimfive | {
"a_id": [
"fft1deg",
"fft2brg"
],
"text": [
"No moving parts. Unlike a common harddrive you don't have to wait for data to be physically retrieved.",
"RAM is designed and connected differently. The design trades off guarantees your hard drive makes (correctness, stability) for speed. This is possible because RAM isn't used for the same jobs - it provides a small fast space where you can quickly compute or change things. The connection is also different, using dedicated broad connections to your CPU that make accessing it much faster. Compare the number of pins (individual connections) on a RAM stick to those on SATA or PCI slots - RAM has 144 to 380, while PCI has fewer than 60. This means that more data can be moved across at once, allowing for faster transfer speeds. --- RAM doesn't _always_ make the same trade offs. ECC RAM, for example, gives you better guarantees ability the stability of memory compared to normal consumer-grade RAM. This is often found in servers and is stable enough that you can boot from it, making it effectively closer to hard drive quality with RAM connection speeds. Very expensive though. Additionally your OS might make RAM somewhat more confusing, as it can trade memory from RAM to disk using page files. This gives more stability (at the cost of performance) as well as allowing programs to use more memory than there is available RAM."
],
"score": [
9,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
|
ev3n9b | Why do watch heart rate sensors, such as the Apple Watch, still read a heart rate when it’s not on a wrist and why is it seemingly random? | Technology | explainlikeimfive | {
"a_id": [
"fft4d21"
],
"text": [
"The way these sensors work is that they shine a light into your wrist and measures the color of the light returning. As your blood pressure pulses for each heart beat the tiny capilary blood vessels in your skin will expand slightly making your skin more red. This is used by the watch to get a rythm which it uses to measure your heart rate. However the signal return using this technique is very noisy. So the watch have to be very liberal when trying to find your heart rythm as it can easily be drowned in other noise. So even if you remove the watch from your wrist and it will only pick up noise the algorithms might still find some sort of rythm burried in the noise. This will cause the watch to display the wrong heart rate as it have misinterpreted static noise or random signals as a heart rythm."
],
"score": [
12
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
]
|
|
ev41gr | Why does "slowmode" in video converters yield a better quality result than "fastmode" despite being the same resolution? | Technology | explainlikeimfive | {
"a_id": [
"fft5xkb"
],
"text": [
"Because video compression is lossy, though it typically doesn't change the resolution. What it changes is the contents. The encoder tries to figure out what parts of the image you'd miss the least, and whether there's any data it can reuse. For instance modern encoders do something called \"motion compensation\". They try to figure is there is an object moving across the frame, and if you can just say \"take the same thing as on the frame before, but move it 5 pixels to the right\". All of that takes a good deal of CPU power. The more power you dedicate the better the results will be, because it gives the encoder more chances to find a more optimal way to do things."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
]
| [
"url"
]
|
|
ev6o38 | what's the difference between threads and cores in a CPU | Technology | explainlikeimfive | {
"a_id": [
"ffttoxm",
"fftnyz6"
],
"text": [
"A thread is a task, a core is a worker. Hyperthreading is where you have multiple tasks prepared at all times for one core so that they can switch between them faster. Hyperthreading doesn't make the core complete single tasks any faster, but it can reduce the amount of time the core isn't doing anything when there are multiple smaller tasks that need to be done. Another ELI5 is by analogy to fast food drive through. The car/order is the thread, the payment/pickup window is the core. Hyperthreading is when you've got multiple ordering speakers for the same window. The biggest benefit is when a thread is delayed because it's waiting on data/instructions (i.e. the person in the car can't make up their mind), but even when things are working smoothly it can help with scheduling (i.e. by being able to prepare food for multiple cars at once and make the transaction at the window smoother).",
"A Intel i9-9900KS has 8 cores and 16 threads. That means that in a way the single-chip has 8 separate CPUs or cores on a single chip. They are independent of each other with all parts duplicated and you can use all eight at the same time for different tasks. It is a bit like if you had 8 separate 1 core CPUs in a computer each one with there own chip, The difference is they take up less space and can share some part like the memory controller. & #x200B; The threads are what Intel calls Hyperthreading and AMD call Simultaneous multithreading (SMT). 8 cores and 16 thread result in each core can switch between two tasks quickly When you run a program on a CPU it will often read data from the RAM. Reading data from RAM can take a long time, it might take the same time as it takes to do 200 sequential addition in the CPU. So you duplicate some parts of the CPU so you quickly cand switch between two different tasks. When one task weight for information from the RAM you can quickly switch to the other tasks that might have asked for data from the RAM in the past and you have not received it. So the ideas is used the time when the CPU in the past would just be idle and wait for data from RAM to do some other tasks. The cores are independent so doubling them can result in double performance, in practice it depends on the program you use. Going from 4 cores, 4 threads to 4 cores, 8 threads might only increase performance by 30% in the best case. So more cores is better the more threads. The reason you do both is that adding 2 threads per core might only make it a few percent largets but one to two cores is almost a doubling in size."
],
"score": [
8,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
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| [
"url"
]
|
|
evd4su | Bank voice id for verification vs google assistant voice detection | Technology | explainlikeimfive | {
"a_id": [
"ffuz0w7"
],
"text": [
"You're misunderstanding Google's feature. The Google assistant is supposed to respond to \"Hey Google\" or \"OK Google\" from anyone, but certain queries will be customized for you if it recognizes your voice. For example, if you say \"OK Google, what's my schedule tomorrow\" it will read from your Google Calendar. But if your friend asks the same thing it won't tell them. There isn't supposed to be a way to get Google to only listen to your voice and not anybody else's."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
]
| [
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|
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