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lvnzp5 | How were syringe needles first made? | These types of needles are pretty small and also hollow. From what I could find, they were invented in the 1840's so technology was already advancing, but I don’t understand how were they made without modern means. | Technology | explainlikeimfive | {
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"> An Irish physician named [Francis Rynd]( URL_2 ) invented the hollow needle and used it to make the first recorded subcutaneous injections in 1844. This link has a picture of His form of hypodermic syringe if you want to look at it. It appears as though this would not have Pierce the skin But rather used as injection into incisions. > The first hypodermic needle was probably made by Francis Rynd in Dublin in 1844, [using the technology of annealing the edges of a folded flat strip of steel to make a tube. This was then drawn through increasingly narrower dies whilst maintaining the patency of the needle.]( URL_1 .) (So many pictures of vintage needles and history of their development. So that is the actual technique that would have been used: making a tube and then making it smaller and smaller. > Then shortly thereafter in 1853 Charles Pravaz and [Alexander Wood]( URL_0 ) developed a medical hypodermic syringe with a needle fine enough to pierce the skin. Alexander Wood experimented with injected morphine to treat nerve conditions. He and his wife subsequently became addicted to morphine and his wife is recorded as the first woman to die of an injected drug overdose. (Richard Davenport-Hines disagrees ‘It is a myth: she outlived him, and survived until 1896')"
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lvqgie | why does a tv make small purple dots when in contact with a finger | Technology | explainlikeimfive | {
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"Liquid Crystal Displays or LCDs work by polarizing or not-polarizing (passing or blocking) the light coming through from the backlight. When you press on an LCD, you are deforming the crystals (bending them), which causes them to change their polarization a little. [Here is an AskScience thread]( URL_0 ) that may be helpful."
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lw0la3 | Is Open Source Encryption really more secure than Close Sourced Encryption | And how so? It feels like because everyone can see the code, it would be less secure, but many people say that programs like signal and bitwarden which use open source encryption are far better than other closed sourced alternatives. | Technology | explainlikeimfive | {
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"They are, not from a technical perspective (both open and closed source software can be great, and both can be trash), but from a philosophical perspective. Encryption exists because distrust in third parties exists. So why should I trust someone to make good encryption software, when the precise reason I use it because I don't want to trust strangers to not abuse my data? If I can't verify what the software does with my data, I could have forgone encryption entirely, since it's just shifting trust from \"I believe you won't do anything bad with the stuff I give you\" to \"I believe you didn't intentionally/accidentally make bad encryption\". Open source is verifiable, and therefore removes the requirement to trust the vendor. e: now one could argue that most users aren't competent to check the source code themselves even if they could. But simply the fact that it's out there means that sooner or later, problems will be identified by someone and the word will get out. That's already a huge incentive to do your work properly as a vendor.",
"\"Here's my closed source encryption. It's unbreakable. I'm not going to show you how it works, but trust me, I promise it's unbreakable. Really-for-real. Honest!\" \"Here's my open source encryption. It's unbreakable. See for yourself! I'll show you exactly how it works so that you can trust it. Oh, you figured out how to break it? Here's version 1.1, and I fixed the problem you found.\"",
"> It feels like because everyone can see the code, it would be less secure This is kind of an illusory feeling of safety. Even if your encryption method is secret, that doesn't mean there aren't attacks that can end up revealing it (known-plaintext attacks, chosen-plaintext attacks, side channel attacks...). In cryptanalysis, it's generally assumed that determined attackers will eventually always know the *method* of encrypting messages; you should concentrate on[ keeping the *encryption key* secret instead]( URL_0 ).",
"You can see the code and test it yourself, you know that they haven’t implemented some backdoor they can use to see your messages even if they are encrypted, and the fact that many people are looking for exploits by looking at the code actually makes it more secure, because good guys can also find vulnerabilities and report them However that doesn’t necessarily make the encryption itself any safer, you can have really safe encryption without it being open source, it just makes it more trustworthy, rather than having to believe a company’s marketing",
"A lot of points have already been addressed, so I’ll just comment on this bit: > It feels like because everyone can see the code, it would be less secure. Encryption is just math. To keep it “ELI5,” think of it like “pick a random number between 1 and 1 billion.” The fact that you can see the workings under the hood doesn’t make it any easier to guess the randomly picked number. In fact, seeing the source code lets people verify that the random number generation truly is random. It would certainly be possible to write a bad encryption program that *says* it’s picking a random number between 1 and a billion, but just always picks the number 7. That would obviously be terrible encryption, but if the program was open source, everyone could see it and publicly call them out. If it was closed source, we might not know how terrible the encryption is until it gets hacked.",
"Imagine two bank vaults with a lot of money inside them. One has been kept secret in the back of the building, and nobody has ever tried to break into it. The other is built into the middle of a public square, and anyone is welcome to try to break into it any time, yet nobody has succeeded. Neither vault has ever been broken into. But which one do you think is likely more secure? Both vaults, public and private, might be very high quality, but because the public one can be tested by anyone, flaws are likely to be identified and fixed. Nothing wrong with closed-source code, but open-source code does have this public-proof advantage.",
"> And how so? It feels like because everyone can see the code, it would be less secure, but many people say that programs like signal and bitwarden which use open source encryption are far better than other closed sourced alternatives. Any time you use closed-source software you implicitly trust the creator on *their* word that the software does exactly what it advertises. You are basically being handed a black box with a button. An important point is also that any piece of open-source software can theoretically be maintained, patched and repaired infinitely by a dedicated community. If a software company goes belly-up and does not publish the source code of their proprietary creations, their programs or formats will inevitably stop working or become insecure as the rest of the world moves on. Open-source software has no expiration date.",
"If your encryption can be defeated by people knowing how it works it's an awful encryption scheme and you should never use it ever. A good encryption scheme cannot be reversed even if you know *exactly* how it works. The method itself is strong enough that if you do not have the key your best shot is guessing randomly. As such \"closed sourced encryption\" doesn't really offer much additional security even if you don't know how it works. It shouldn't matter to begin with. However the idea is that in the case of open source encryption anyone can see it, identify holes or security flaws, and suggest fixes. It also removes the need for implicit trust: I don't need to trust that you've implemented it correctly and haven't intentionally added any holes."
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lw2cj3 | When you turn a cable television on with a remote, is the TV or cable box actually responding directly to the remote, and how is the other triggered? | Technology | explainlikeimfive | {
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"They are both always listening for a signal. When they receive a signal they are programmed to respond to in a certain state then they act. Example: Your TV recognizes when you hit the volume button even when off, but will only turn the volume down when the TV is on. If the remote is set up to trigger the cable box then the TV, it’ll send a power on signal to both devices. Some TVs will power on when they receive a new video signal such as when a connected device turns on. It really depends on by the capabilities of your TV and your remote.",
"The remote has an infrared emitter, and the device you're turning on has an infrared receiver. They will communicate a command like \"on/off button was pressed\". Everything after that is handled by the device you just turned on. If the remote is for your TV, then it's the TV handling all of that; If the remote is for the DVR, receiver or cable set, it would be that device handling the command."
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lw7gmc | Why is it that when mixing colors on computers/phones, the maximum “amount” you can use of each is specifically 255? | Technology | explainlikeimfive | {
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"When you have a byte ( 8 bits ) to represent the color, the values are between 0 and 255 because in binary that’s the maximum value 11111111",
"Rgb are historically store as 6 hexadecimal Numbers (2 for each color). 2x16=256 possibilities.(0 to 255)",
"The amount of each primary color (red, blue, and green) is represented by a single 8-bit unsigned integer. Binary values range from 0 to 2^n - 1, where n is the number of bits in the integer representation. For an 8-bit integer, that range is from zero (binary 00000000 or hexadecimal 00) to 255 (binary 11111111 or hexadecimal FF). That is for each color, but of course you have three colors that can be combined in any proportion, so the actual possible number of colors is 2^24 = 16,777,216. This exceeds the number of colors which scientific consensus seems to indicate can be differentiated by the human eye, which is approximately ten million, so a more complicated representation is not required. It is certainly possible though. For example, if you used a 16-bit integer for each color, the range for each would be from zero to 65,535 (2^16 - 1), and the total possible number of colors would be 2^48 , or approximately 2.8 x 10^14 colors. This would be wasted on human eyes though and isn't worth using twice the storage space to encode color information for every pixel."
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lwa69s | What’s the difference between A.I and a really clever piece of software or computer? | We are seeing a lot these days about A.I but I have seen a few things where I’ve thought, that’s just something a piece of software can do...why are we now calling it A.I? | Technology | explainlikeimfive | {
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"Well, \"AI\" means so many things that it doesn't mean much, it's very like \"software\" in that regard. The best chess and Go players are programs, but their \"intelligence\" is very, very narrow. The better term might be AGI, artificial general intelligence. This is \"intelligent like a five-year-old\", including the ability to learn anything with focused education. AGI would be substantially different from the cleaver software we have today.",
"We’ve been moving the goalposts for what counts as AI for a few decades now. In the early days, one of the milestones to making an AI was making a computer that could beat a human at chess, which lead to advancements in game theory, and some very skilled computers. When they finally beat humans at chess, we realized that a specialized computer wasn’t really intelligent and the definition of a “true” changed. That’s happened with pretty much every milestone. Image recognition? Difficult, not intelligent. Machine learning? Cool party trick, but it’s still specialized. Can it hold a conversation? You programmed it to do that. That last one (passing the Turing test) was considered one of the biggest goals in AI research, but it has its own problems. One famous thought experiment known as the Chinese Room compares a talking computer with a locked room and a bunch of (non Mandarin speaking) people who follow directions. If you send a message into the room (in Mandarin) and the people inside have a massive rule book that tells them what to respond, so that you always get a coherent response (also in Mandarin), are you speaking with anybody? Does the room itself count as intelligent? Basically, it’s a big question that philosophers have been dealing with for ages. There’s no good answer."
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lwean5 | Blu-ray resolution | Why do some remastered films released on Blu-ray mention a “4K Scan” when the blu-ray resolution output is limited to 1080p? | Technology | explainlikeimfive | {
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"What they have done is scanned the original film in 4K format and then digitally downsampled it to HD. Normally the digital downsampling process is able to do this process smarter and are able to preserve a lot more features then if you were to scan the film with an HD scanner. For example the downsampling algorithm might be able to detect film graining in the 4K scans and eliminate these effects in the HD output. It is also easier to detect sharp lines and smooth transitions which you can preserve better in the downsampled output. They do a similar thing with 4K movies where they will scan in 8K or 10K before downsampling. At those resulotions you are basically just scanning the invididual film grains anyway. But even when they are shooting new movies digitally they will use 8K or 10K cameras as it gives them a lot more options with digital effects and even things like cropping before downsampling to 4K for consumers.",
"Regular Blu-ray is indeed limited to 1080p but there exists a 4K Ultra HD Blu-ray standard"
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lwgavj | What's the difference between measuring a person's temperature and an object's temperature? | I got a contactless thermometer, one of those ones that you just hold near your forehead for a sec. It has different modes for measuring your body temperature and measuring object temperature (plus a room temperature one), and doing a reading on my own forehead in each mode gives different numbers. Why is there a need for the separate modes, and what's it doing differently in each? | Technology | explainlikeimfive | {
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"Some surfaces radiate heat better than others, just like some surfaces reflect light better than others. When the thermometer only registers a small amount of heat being radiated by whatever you're pointing it at, that may indicate that the object is cold. But the object could also be hot and not good at radiating heat (such as shiny metal objects). In order to calculate the temperature accurately, the thermometer needs to know what kind of surface it's dealing with. When you set the thermometer to body temp mode, it applies a certain correction factor for human skin, whereas it's going to use a different value for objects, even though that value can only be a guesstimate. The property that we're talking about here is called emissivity."
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lwk51n | Why did 16:9 become the standard widescreen format despite 21:9 being the normal aspect ratio for cinema and optimal for content consumption? | Technology | explainlikeimfive | {
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"It was the only ratio that fit neatly in all existing standards at the time. see this [image]( URL_0 ) There are numerous sites on the topic. URL_1",
"There were a lot of different sizes being experimented with. First of all 21:9 isn't some magic standard size that we should think about, when the HDTV standard were being developed, there were a lot of thoughts on what to make the ratio and eventually they settled on 16:9 because mathematically, it was the best option and had a good practical capabilities (that you want wider than tall for movies, but too much and it gets weird). I have no idea why you're magically thinking 21:9 is some special or \"better\" ratio. 16:9 became the standard because it was a ratio that basically had a good solution to \"fit\" the variety of different aspect ratios that existed in movies and TV at the time (TV was 4:3 but movies were all over the place). In the end it was just a bit of an equation to find the right aspect ratio that worked the best-- and it was 16:9, thus, here we are."
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lwk6tr | What makes headphones "high quality"? | Bassy headphones, noise canceling, what makes them sound better then a pair in walmart on a technological level? Edit because I couldnt explain properly: Im asking what makes the sounds and why cheap headphones less great. | Technology | explainlikeimfive | {
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"The strength of the magnets used to make the sound. Rare earth elements are required to make magnets strong enough to make \"high quality\" sound. That's why those knock off airpods don't sound quite as good as the real thing, even though they look the same.",
"Apologies, but I don't fully understand. Are you asking why bassy headphones sound better, technically? Like, why are they bass heavy or why do people find heavy bass appealing? I ask as you could absolutely get a pair of cheap bassy headphones, so that's not really the differentiation between an expensive and a cheap set. Counterintuitively, some of the best headphones out there aren't bass heavy, but try to be as neutral as possible.",
"1. Frequency response or driver (speaker) output. Is it being able to create loud enough sounds across the frequency range to be heard? Cheap 5$ headphones typically just have no low frequency output, or it is heavily distorted. 2. Low distortion. Are the sounds clean, or do they buzz at decent volumes? Low distortion requires linear performance of the driver in its range of operation. Meaning, an input wave has to be reproduced truthfully at the ear. All drivers distort. Good drivers distort at higher volumes. 3. Seal. Good seal ensures higher effective volume, by plugging any possible leakage. Good seal also reduces entry of external noise into the ear, and increase signal to noise ratio. Active noise cancelation further reduces external noise, and lets you listen properly st much lower volumes. This means less chances of driver distortion, and a better soundstage. In general, seal is a part of the larger mechanical+acoustical architecture, which includes shapes of components and their coupling to the ear. 4. Signal processing. This, when done properly, makes up for many of the shortcomings of the headphones, be it acoustic performance or mechanical coupling to the ear. Good signal processing takes into account the acoustics of and around the ear, the music being played, etc. so that the listener can utilize the most of their dynamic range of hearing and \"get the most\" out of the music. Then there's stuff like low connection latency, UI/UX, etc.",
"While sound behaviors can be measured objectively, sound preference is very subjective. That said, there are general (read: largely held by a majority of people) sound behaviors that are considered \"better\". You may see terms like \"high quality\", HD, audiophile, reference, etc. First, a given set of headphones (or speakers) will be \"tuned\" to behave a certain way; this is a combination of the materials, design and electronics that are combined to create the headphones/speakers. Second, materials and craftsmanship matter. What the speaker diaphragm is made from (is it cheaper paper - may absorb ambient moisture and change shape/mass over time - or are higher quality and more expensive polypropylene or even metal?), the quality of the inner components and associated electronics, all play a part in \"quality\" A good place to try to answer this question from is to consider what \"reference\" means in this context. Reference is typically used to indicate a sound reproduction that is as close to the recorded material as possible. That means the headphones or speakers wouldn't favor or increase bass (though some people love this), and instead would remain \"neutral\" and let the material speak for itself, as the artist intended. Many purists consider this to the hallmark of quality. But it's not wrong to prefer super heavy xxx bass boomers, if that's your thing, or ultra twinkly high end screamers, etc. Other features (all part of tuning) that generally tend to be preferred and therefore contribute to quality are things like soundstage (how wide - or narrow - the headphones sound), impedance (how hard it is - aka how much power it takes - to \"drive\" a speaker to make sound) can impact how well a speaker conforms to the source material, etc. Lots of bits and pieces here, but you put it all together and you get varying levels of \"quality\". Only YOU can determine which sound is preferable and therefore of \"higher quality\". edit: interesting memory from a long ago time; I've always loved audio equipment, and I spent some time selling high end gear way back in the day ('90s). There was a saying back then: \"No highs, no lows, it must be Bose\"; they were considered to be a more \"pure\" option as they didn't alter or inflate bass, treble, mids, etc. and instead aimed for that \"reference\" sound."
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lwth5v | Is there a difference between a high end CPU running at 5GHZ and a low end (overclocked) CPU running the same speed? Without counting the obvious CORE count | Technology | explainlikeimfive | {
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"Your CPU is not only the clock speed. There are other factors, like cache size, PCIe version, drivers, and so on. If your CPU runs at 5GHz standard it is probably much newer and has not only a better clock speed, but is better any metric that determines its abilities. So it is not a given, that the high end CPU is better, but very probable.",
"There will still be some difference in some cases though not that drastic. High end and low end of the same architecture (i9 and i3 of the same generation) won't have much difference but modern processors can beat overclocked old processors on many tasks. First, 5 GHz means that the processor is doing 5 billion elementary operations per second but the set of these elementary operations can be different. Some stuff (like calculating a sum of two arrays or operating on very large numbers) can be done in a single tick on a modern processor while an old processor would need to split it into several ticks. Second, modern processors usually execute several operations at once because different operations are computed on different parts of the processor (adding two integers and multiplying two floats will utilize different parts of the core and if these operations are independent, they can be done simultaneously). The processors even try to predict what the \"if\" statement will end up with to start executing the next code branch ahead of time. Here, more capacity for simultaneous execution and more advanced prediction / reordering algorithms will help the processor work faster. Third, you cannot fit all data within the processor and reading it from memory is horribly slow compared to the processor speed. If a processor requested some data and cannot continue without it, it has to stall and wait until the data is delivered. Hence, processors have several levels of cache memory: increasingly smaller but faster memory sets which store some of the data that is constantly being used. Modern processors have larger and faster caches which will come in handy in some tasks.",
"If we're talking about two CPUs from the same manufacturer from the same generation... yes. The way they manufacture the processors, they make a big batch of hundreds of them all at once, and then thoroughly test them. The ones that perform 100% perfectly are packaged as high end CPUs, and the ones that have flaws have the faulty sections disabled and are sold as lower end CPUs. This means there are two different ways that the low end CPU can be worse than the high end one at the same clock speed: * The low end CPU will have less cores to work with, so it will not be able to do as many parallel (simultaneous) actions as the high end CPU. * The low end CPU is more likely to have sections that are slightly faulty but still usable. What this means is that the CPU may be fine at normal clock speeds but unstable at higher clock speeds, leading to crashing.",
"It depends. Are they exactly the same chip, but one's just clocked higher? Then yes, same performance. Here we get into chip manufacturing. When chips are made, they test them to see how good they are. One chip may successfully clock higher than another without going over the heat maximum, so they sell that at the high end, and the others at the low end. Trying to clock the low one higher will need lots of cooling because it didn't test out at the higher clock rate, and you may run into other issues. Back around 2000 AMD had the reverse issue. Their manufacturing was too good, and too many chips were testing at high clock rates, not leaving enough to sell for the low-end market. So they just capped some at a low rate with a resistor and sold them as low-end chips. People found you could fix that and run them fast with no issues. But if you're thinking an i5 vs. an i9, there are a lot of other differences between those chips than just clock rate that make the i9 faster."
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lwttvb | What is the difference between Stack and Heap Memory? | Technology | explainlikeimfive | {
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"The way things are added and removed is the main difference. Heap is like a pile of leaves where you can add leaves and remove them as needed. Stack memory is a FILO(First In Last Out) queue. It's like a can of Pringles. You can only take out the top chip. If you want to add chips you can only put them on top of the highest one."
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lwxxzm | Why are car's external temperature reading so wildly inaccurate for the dust few minutes of driving? | Edit: first, autocorrect changed it to dust 50F out, I get in my car and it's reading 64F out, drive for 5 minutes and it's reading 50F. Why is this? | Technology | explainlikeimfive | {
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"The sensor is traditionally located somewhere on the bottom of the engine compartment. It has to be outside of the main body of the car, and it also can't be above the engine or it would pick up engine heat as it rises. The problem then is that it's really measuring the temperature of the road. If you happen to be parked on a clear black driveway that's picking up a lot of sun, it might read hot. If you're on a snowy driveway and you haven't seen the sun in weeks, it might read low."
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lx077z | where is my cloud storage based? Like physically? | Hey ELI5! I was wondering today where the physical storage for cloud storage is. Like actually located? For specifically OneDrive from Microsoft | Technology | explainlikeimfive | {
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"In some data center, somewhere, and for redundancy reasons, likely in more than one location. So what the hell are these? Basically they are just immense warehouses on some random plot of land somewhere, often times they are in more rural areas or places with low cost of real estate or low electricity costs (they use a ton of power, to both run the computers and for cooling the site).",
"So Microsoft owns a bunch of datacenters all over the world. These datacenters are basically a warehouse chock full of servers and hard drives (well, increasinly solid state drives but that'sabother issue). \"The cloud\" consists of datacenters like that regardless of the service. Most major companies have more than one, while smaller companies are renting space in someone else's datacenters like amazon's. Those with multiple like Microsoft will store your data in a regional datacenter near you, with backups for that data both locally and in physically distant centers in case something like a fire or flood wrecks that whole datacenter. The methods for choosing a datacenter as the primary location for your data varies. For example Microsoft does a degree of specialization for different 365 platforms. You'd access a storage specialized facility for onedrive and sharepoint while other centers focused more on processing power handle things like the web applications of microsoft office. In different countries and regions the level of differentiation/specialization varies. Frequently some sort of algorithm based on the most used IPs for your account or the IP used to create it is used to select the nearest appropriate datacenter. The exact methodology for determining all of that is proprietary and a bit opaque, but the jist is that it's probably in a warehouse just outside a major city somewhere in your general region.",
"Expanding on the existing good answers, [it's likely going to be in at least one of these buildings]( URL_0 ). Whichever one is closest to you in network-distance is a good guess, and probably at least one other one for redundancy.",
"It's physically located on storage that is connected to the cloud servers. In the case of all major cloud providers, they have servers and storage in datacenters all over the USA and in some cases international. Ultimately though the data is stored on HDDs and SSD drives.",
"\"The cloud\" is just someone else's computers that you use. Where those computers are depends on whose cloud service you are using and where you are. Microsoft has ten major datacenters in the US running cloud services, on the coasts and in the middle of the country. So if you live in Texas your data is likely in San Antonio. But they also replicate data between datacenters in case one goes down, so your data could be at any of them.",
"Most cloud-based storage is redundant. Google, MS, Apple etc have lots of datacenters around the globe. These datacenters have compute resources that access a Storage Area Network (SAN), which is basically a whole bunch of hard drives bundled together and put on the network. Your OneDrive document would be processed by the compute resources, which will store 2 or more copies on various SANs (typically geographically distributed, for example one in New York and one in Los Angeles so that a natural disaster doesn't take out both copies at the same time). The SAN itself also has [redundancy]( URL_0 ), so that a failed disk does not wipe out the data on the SAN (and with the number of disks we're talking, failures are frequent -- somebody's job is to walk around the datacenter replacing disks all day)."
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lx1m1r | How do camera stabilizers work? | Technology | explainlikeimfive | {
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"There are two main types of camera stabilizers. The simple version has the camera on a rod that can move freely and weights at the other end. The more weight, the more movement is dampened between the handhold and the camera. Gyro stabilisers like the ones for hobby drones or for mounting cellphone cameras on use a sensor that detects movement, the sensor sends signals to a computer built into the gimbal, and the computer activates electric motors that counter the movement of the hand."
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lxbbn4 | Why is lithium so important for electronic vehicles? | Technology | explainlikeimfive | {
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"Electric vehicles, unlike internal combustion engine vehicles, cannot generate power on demand. They have no fuel to burn. Instead, they must be charged and must store energy for when they need to drive. We use batteries to store energy. We're much better at generating energy than we are at storing it. Batteries kind of suck. The best batteries we can build at an industrial scale are ones based on Lithium. They're very easy to recharge without harming the battery and tend to have a longer lifespan than many others we could build."
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lxf7v1 | In a world full of VPNs, how do governments and corporations point a finger at a certain country for hacking their infrastructure? | Technology | explainlikeimfive | {
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"Some methods of identifying the origin of the attackers could include looking at the code of the malware; what languages are used? Although this has been used by attackers in the past to pose as another nation (the creator of the Mirai botnet wrote \"i love chicken nuggets\" in russian as a comment in the code, and the americans were looking at russian sources for a few months. the creator was american). Other methods include looking at the TTPs (tactics, techniques, and procedures) used during an attack. For example, if a certain APT (advanced persistent threat) group was observed using a specific technique in terms of reconnaissance, followed by another specific technique to gain initial access, then we can build activity patterns. If we see similar activity being conducted towards similar targets (let's say, all the targets are in the finance industry within the same country) then it is widely believed that it is safe to assume this was the same group. Personally I don't much agree with this last one, as it is easy to copy techniques and attack vectors. I asked this exact same question to a superior of mine in the cyber industry who has worked for NSA and he told me that in most cases, secret government agencies have wiretaps, moles, and compromised / insider sources that give them reliable info on who the source of the attacks is. This is why you'll never see a detailed article explaining how they know that a certain country has allegedly attacked another. My follow up question was \"then how do we, as civilians, know for a fact that this country really has attacked this other country, without just blindly accepting what we are told?\". His answer, \"you don't\".",
"> In a world full of VPNs, how do governments and corporations point a finger at a certain country for hacking their infrastructure? Something as trivial as an IP log of recent connections isn't really a relevant factor in these situations. Some concerted efforts of targeted digital vandalism are so demanding and complex, so expensive and resource-extensive, that the only conclusion left to make for any security auditor is that the attack was conducted by another *nation*, as only another nation could have had the means to do it. The rest is following up on individual leads, money trails and narrowing down motivations and capabilities - regular (albeit high-level) intelligence work. Actually publicly pointing a finger is a whole separate diplomatic decision though and can, of course, be done either with or without any evidence."
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lxi0at | How can themeparks snap a crystal clear picture of you on a rollercoaster going 70mph | Technology | explainlikeimfive | {
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"Motion blur occurs when the camera takes too long to generate the image. By the time the last bit of information is taken, the image has changed noticeably. So if all the information is taken in a very short moment, that difference is very small and the image looks sharp. However since the camera has less time to collect the light for the picture, shorter exposure times need a brighter scene. So the flash needs to be stronger or the scene just needs to be very well illuminated.",
"To further the other comments - if the location where they choose to take the photo is lit primarily by the flash (and I've not seen a roller coaster photo where that is not the case) then the duration of the flash effectively becomes the shutter speed (because the image is lit by the flash - and the camera can only capture an image while the flash is \"on\"). Flashes can have *extremely* short durations (1/1000 down to 1/20000 of a second) this means that they are really good at stopping motion.",
"Three things: 1. They use fast shutter speeds. That means that the shutter is only open for a very short period of time to gather data. And during that short period of time, you don't move much. Imagine you took a video at 3200 frames per second, then advanced it frame by frame. The movement would be almost imperceptible. That is how much you move while the shutter is open. They probably shoot at 1/3200th or even 1/6400th. The down side to having the shutter open for such a short period is that there is not much light that gets through in such a short period of time, so... 2. They use bright, fast flashes. That flash will pulse with each shutter click and it will be timed to illuminate the riders for the same length of time. So the riders are getting hit with a very bright light for only 1/3200th of a second and anything that happens outside of that window is too dark to really process. 3. They use angles to their advantage. Look out the side window of your car on the highway and things will be zooming by and you can't really focus on them. But look out the windshield and you can easily focus on approaching items. Cameras have a depth of focus. These particular cameras are set to focus on a point in space that is let's say...3 feet deep. So as the riders are approaching the camera from the background toward the foreground, they will remain in focus for 3 feet as they pass through the camera's view. In 1/3200th of a second, they will probably move less than a quarter of an inch. So there is plenty of time to capture them in focus. But if that camera were placed perpendicular to the coaster train and shooting from the side, the riders would zoom through the view much faster. It's the difference of trying to catch a baseball thrown toward your face and trying to catch a baseball thrown *past* your face from the side. It's much easier to see it coming straight on.",
"A blurry pictures is normally due to one of two things: 1. Unfocused lens 2. Moving subject In normal cases a camera needs to find the subject, focus on it and take a picture before these settings need to be changed to keep a clear picture. In a rollercoaster camera you place the camera in a set place and calculate the focus of the lens and the position of the subject before the picture is taken. When the train reaches a camera trigger the camera takes a picture of this already decided place. Anything there will be sharp. The trigger sensor helps the camera to know when the subject is at the “right” spot. This in combination with a decent flash is what results in a clear picture.",
"They can use a fast shutter speed because they have the flash lights. If the lights didnt flash when you went past there wouldn't be enough light hitting the lense in the time you were there, so the image would be dark. If the shutter speed is lower you get motion blur."
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lxjwb8 | what does Spring Boot do? | Reading about the framework Spring and having trouble understanding what Spring Boot and Spring Batch does if someone has a simple analogy and what was the old way of doing things and what Spring solves? | Technology | explainlikeimfive | {
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"I don't have extensive experience in it so I'm sure others can explain some of the finer points, but one of the major things it does is it's a standalone web application. You don't need to configure a web server, or manage server settings, or anything like that...you build your application, and double-click the executable and your web application runs all on its own. Old Method: Choose and download/install web server software - > Configure web server - > Build and Deploy web application to server Spring Boot: Build and deploy web application",
"Spring allowed you to wire together bits of an application to make it do whatever you want, but didn't do it for you. So you had to have lots of configuration files telling it how one thing relates to the other. For example, you would need to say that this class need to be initialized before this one, and to get some data from this other file to set a field in that class, etc. Spring boot has some of the wiring built in so it is easier to get things up and running with less need to \"boilerplate\" configuration, especially if you use starter templates for specific types of applications like web apps. The trade off is you need to follow it's conventions and it is a bit if a \"black box\" with lots of stuff happening behind the scenes. Spring boot starter templates also give you built in commands to test, deploy, and run applications so you don't need to write them yourself, which is a huge time saver."
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lxl5kc | Why do computers slow down, but then you restart them and they work again? | Could you explain in the form of an analogy? Also, has this improved over time? Does it have anything to do with registry and defrag? Is it different for Mac vs PC? Thank you :) | Technology | explainlikeimfive | {
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"* Think about a computer like this: * You are sitting at a large desk next to a huge set of bookshelves. * You are the CPU * The table is the system memory (RAM) * The bookshelves are the system storage (Hard Drive, SSD, external drives etc) * In order to do something, you need to take the related stuff off the shelf and put it on the table. * Now think about what this table will look like as you start to do your tasks. * Computers appear to do many things all at the same time. * The truth is they only do one thing at a time but very very quickly switch between tasks. * So the table gets filled with things you're working on very quickly. * Switching between these things starts to get time consuming. * Restarting the computer is the same as putting everything back on the shelf and totally clearing off the table. * Those first few tasks you do will be quick because you aren't searching through a table full of stuff to get what you need.",
"There are several reasons, but one of the most-common reasons is that everything you do on your computer takes up some of the limited memory in the computer (specifically the RAM, or Random Access Memory, which is different than space on a disk). As you do things on the computer, such as browse Reddit, your computer keeps taking up more memory with every post you click, every photo you view, every link you click. When that memory becomes more limited, your computer operates more slowly, as it struggles to try to \"find a place to fit more stuff.\" However, once you restart your computer, most of that memory is wiped clean and you start fresh, so your computer is often faster. Basically, on a restart, your computer \"empties the trash can,\" so you can start filling it up again, without constantly having to try to compact the trash to fit more in the can.",
"Follow up to your question about defrag: You'll recall the analogy about hard drives being a file cabinet. While it does store the data, it's not really in the shape of a file cabinet. Instead imagine a grid; letters going across and numbers going up and down. When it needs to store some information it'll take, for example, 5 blocks of space. So it'll just choose A1 - A5 and put them there. But what if one of those blocks is occupied? Now being human your first instinct would probably be move that occupied one somewhere else and then lay the 5 blocks from the same program all next to each other. The computer doesn't do that however. The computer uses a firm \"Any available surface\" method of filing. So if block A4 is already occupied, it'll choose A1-A3 & A5-A6 to store the information. But it does this for everything stored on the hard drive. So a visual representation of the hard drive would be less like a filing cabinet, and more like the warehouse from raiders of the lost arc; along with needing a treasure map to find the relevant information when it tries to pull it. [ URL_0 ]( URL_0 ) Any time it needs to put down something new it will find anywhere it can cram a part of it and make a note of \"I left pieces here, here, here, here and here' for when it needs to grab them again. That's where hard drive speed comes in for computer speed, how fast it can go sorting through all those boxes and pulling the relevant info. Defragmenting the hard drive is when the computer will actually go through and rearrange these boxes into a fashion that makes more sense; grouping bits of data together in actual patterns rather than at random; so when it needs to find something it's less like following a treasure map and takes less time. PSA: Solid State Hard drives (SSD) you do not want to defrag. While they are the raiders style of organization, it's actually carefully controlled so that it distributes wear and tear evenly on the hard drive; improving it's lifespan. A normal hard drive once a 'shelf' breaks it's corrupted, and can cause more and more problems as it tries to work around that. SSD's will calculate and arrange things on the fly so prevent any of those shelves holding boxes from getting an unusual amount of wear and tear; meaning they will last longer without breaking. Defragmenting and manually rearranging the load will mess with it's carefully designed system and put additional strain on portions of the drive, shortening it's lifespan and eventually leading to damage and failure. A SSD can last much much longer than a spinning drive hard drive because it's storage method intentionally sets up to keep it going a longer and messing with that can shorten it's lifespan."
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lxm1yp | Why is Tom Cruise typically used as the deep fake model? | Technology | explainlikeimfive | {
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"Because Tom Cruise is both instantly recognizable and *just* ~~crazy~~ unpredictable enough that you’ll likely believe the deep fake for at least a moment.",
"Deepfake and other image stitching technologies like it require a good amount of source data such as pictures of someone taken from all angles, all facial expressions, as many lighting schemes as possible. What your saying ok a deepfake is a reconstruction of Tom Cruise's face onto someone else's face. More source pictures/video to draw expressions from means a better and more believable reconstruction.",
"There are an absurd amount of photos taken of Tom Cruise through the years. And he still looks the same now as he did as a teen. When you are doing articifial intelligence and patern recognizion software you want as much data as possible to get a good result. And you would be hard pressed to find a celebraty there are more portraits of then Tom Cruise."
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lxq171 | Why are SSDs reliable for long-term storage, but USBs fail within a few years? | Since both SSDs and USBs use flash storage. I tried searching online and found [this thread]( URL_0 ) and [this video]( URL_1 ), which were somewhat helpful but not entirely. Does anyone have a great analogy or digestible summary? | Technology | explainlikeimfive | {
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"Different levels of reliability in the controllers and how they're built. The basic storage technology is the same but SSDs use a much more robust construction that can withstand more read/write cycles before they accumulate too much damage to function, more sophisticated controllers to spread the damage around, and redundant sections to take over if one section fails. Think of it like tires on your car. USBs are cheap tires...eventually one of them is going to wear out and pop. SSDs are expensive long life tires, and you do rotation, alignment, and balancing all the time to make sure they're in good condition, and you have a full size spare."
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lxw1k0 | Our brain uses about 10W of power, when a computer can use 100W. With our brain doing significantly more than a computer, how is it so much more efficient? | Technology | explainlikeimfive | {
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"Your brain is nothing like a computer, architecture-wise. Computers use programs that are millions of simple instructions from a set of a couple hundred instructions. The brain is parallel, executing a few hundred instructions from a set of zillions of complex instructions you call \"thoughts\".",
"> with out brain doing significantly more than a computer Can your brain do millions of additions or multiplications per second? Your brain is not doing all that much in terms of raw logic.",
"The real answer is that billions of years of evolution have optimized biological organisms for energy efficiency. But in a sense, that doesn't really answer the question. *Why* are brains so energy efficient? I suspect one of the main contributing factors to be the way the brain is structured: it's very \"sparse\", in a sense that, at any given point in time, everything not currently needed is \"turned off\". You may have heard that only a small fraction of the brain is \"in use\" at any given time. What this means is that, in a sense, the brain is doing the minimal amount of work necessary - only updating state where it's relevant to the task at hand. Conversely, computers tend to be big and stupid and simple and full of logic gates that flip whether their results are needed or not. Modern CPUs have started selectively enabling and disabling parts of the hardware based on what's currently needed, but it's many orders of magnitude less sophisticated than what the brain is capable of doing. Also, despite almost a hundred years of engineering, transistors are still very energy inefficient. They don't just propagate state changes, they also waste a bunch of current in the process."
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lxzker | How does a phone/computer process the power button being pressed if it’s off? | I tried google and all I got was “pressing the power button to turn it off won’t damage it anymore.” | Technology | explainlikeimfive | {
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"There are two basic solutions, but in both the button is really just a signal, it’s not the actual source of power to the entire device. In the first, the device is not 100% off, but rather there is a tiny circuit still awake drawing a **very** small amount of power, waiting for the button to be pressed. When it sees the button pressed, it will activate the rest of the machine into waking. The other solution has the power button run from the power source to a small circuit that is off until briefly powered up when the button is pressed. When it wakes, it will wake the rest of the circuitry and the device will power up. It’s kind of like someone listening for a bell to ring in a shutdown factory, when they hear it, they will start powering up everything in the building (lights, machinery, etc) and getting it all going. That little bell didn’t ’t do anything, but it woke up the one guy who could turn it all on.",
"For computers: When you power the computer, there's a single hardwired instruction to the CPU that is executed (a JUMP). It tells the CPU to load the first instruction of the BIOS. The BIOS is a chip with ROM memory that has the set of instructions, it first test if the devices are ok, and if everything is ok, it will load the first instructions stored on where it is booting (mainly the HD, but the user can also boot from another device, like a flash drive, or a DVD), those first instructions basically tells the the CPU where everything is stored, and then loads a program called bootloader. The bootloader will then load the kernel, and from there, the kernel will take control of the computer.",
"There's a little bit of standby power in every device, as long as it's plugged in. Pressing the power button completes a circuit; that circuit uses the standby power to energize other circuits, which energizes still *other* circuits until the device is operating at full capacity again."
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lxzyk7 | What is an NFT? | Technology | explainlikeimfive | {
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"Nft stands for non fungible token. It is a way to digitally represent ownership of something digital (NBA topshots is a good example of this) backed by the same technology that underpins crypto currencies. It's called a block chain, and uses encryption and distributed computing power to validate all transactions. In other words, you can \"own\" a digital picture or video and have proof that you do, which cannot be copied or replicated."
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ly3sen | How does touch-screen work? | Technology | explainlikeimfive | {
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"(I hope this doesn’t sound condescending or pretentious, I’m literally gonna try explaining like you’re five, not that this is an easy or intuitive thing to understand) Throughout our bodies we have nerves and they send electricity to our muscles and makes them move and flex, when we touch a touchscreen like on a smartphone it senses that electricity in our bodies, it’s not a lot of electricity at all so you don’t feel it, that’s why objects that don’t have any electricity or block electricity from reaching the screen, it doesn’t work. Older or lower budget touchscreens that you might find in a convenience store or sth have pressure sensors when you press down on them in a certain spot it senses that.",
"Oh! I actually kinda know this! Most modern touch screens use whats called Capacitive touch. This means that the device can measure the electrical interference that you generate when you touch the screen. This interference is interpreted by software to a location on the screen, where it puts the pointer."
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ly4xyg | how does remastering old videos which had a lower resolution into HD or a higher resolution work? | Technology | explainlikeimfive | {
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"It was shot on physical film. Film doesn't have a resolution the same way that digital video does. And it captures a lot of detail, so you can scan it in 4K no problem.",
"URL_0 If the original was only on video then nothing you can really do since the higher resolution doesn’t exist. It may look slightly crisper with better color correction via computers. As an example, some of the original Honeymooners tv series were only saved on a fairly new and primitive video system and looks like pure crap because there’s not a ton you can do when the source recording is poor quality."
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ly66ae | What is the crunchy sound you are hearing when a hard drive is reading and writing data? | Technology | explainlikeimfive | {
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"Take a look at this diagram of a hard drive. URL_0 The hard drive consists of spinning metal platters, a read head that overs over those platters and an arm that moves the head into position. The crunching sound you're hearing is the arm moving the read head into various positions very quickly. That's why you hear it more when doing lots of small reads or writes. If you're reading or writing data sequentially then the arm doesn't have to move so much and you don't hear the sound.",
"Inside a hard drive specifically (hdd not ssd), is a little disc, beneath an arm kinda like a record player if you think about it. So when something says that it's writing, that information is being recorded on tiny moving parts (correct me if someone knows this is wrong, it's just how I was taught). This is what makes the scratchy noise. This is also why hdds are much more common to fault, as opposed to solid state drives (ssd) that have no moving parts"
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ly6f1c | How do VPNs work? | I understand there are general concepts like Full and Split tunnel, I just can’t grasp the concept according to textbooks. What makes different models...well, different? | Technology | explainlikeimfive | {
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"i'magine your computer is your home. regular, unprotected connection to the internet is done by using your front door or window... everyone can see when you come, when you go, and if you have visitors or deliveries. using vpn's is like digging a hole into your neighbors baseement (with permission) and you use their front door/windows. While using your neightbors isn't that much improvement, it makes it harder for anyone to say it was you doing comeing and going. But VPN are much bigger than that... you're neighbor is a bad ass, and the entire neighborhood has tunnelled into their basement and their activity obscures your activity. now mix in some encryption... basically anyone and anything that comes/goes at the frontdoor/windows is always in the shape of an ominous black box.",
"Assuming you know how a vpn works in general, the difference between a full tunnel and a split tunnel is how much of your data goes through the VPN. In a split tunnel, only data going to a certain network/location/server etc actually goes through the vpn. The rest of your internet traffic goes straight to wherever its going. A full tunnel means that every bit of data that leaves your computer to somewhere on the internet goes through the VPN first.",
"The internet works like the post system but faster. Instead of sending a letter directly and having the post people see who you're writing to you put your letter in another envelope and adress it to some VPN company. They open the letter, find your letter already adressed to the actual receiver. They write their own adress on it to tell the receiver who they should answer. So you basically put an instance between you and the receiver. The receiver won't find out your adress, and the police can only find out who you're talking to by going to the VPN with a warrant (and some are obviously out of their juristication, or simply keep no records at all) And as a bonus: TOR network works exactly like this too, but instead of just using one middleman you put your letter in 10 envelopes that are locked and can only be opened by the correct next middleman. So noone at the start of the chain can find out who the receiver is, and at the end noone knows who the sender is."
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lyex9p | How do those walk-through scanners in libraries know if you're taking a book without borrowing it, especially if those books don't have metal inserts or anything like that? | How does the library borrowing system work? and how come even if there is no obvious metal insert in the book those gates still know when and when not to beep if the book has or hasn't been borrowed? & #x200B; EDIT: Thank you all so much for the answers!! : D | Technology | explainlikeimfive | {
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"> especially if those books don't have metal inserts or anything like that? Because it DOES have metal inserts. They are called RFID chips, and they are very small and very cheap. You can even buy them. I suggest google image: \"rfid chips label and tags\"",
"I work in a fairly poor urban library and we do use RFID chips, which are great for self checkin and checkout. They're on everything, including wee DVDs. Every few years we have a run on toilet paper (in one series of instances, a lady would bring a bunch of kids in a couple times a week and they would break the paper holders and conceal massive amounts in the kids' backpacks). A bunch of RFID tags inside the TP rolls, and you've found the culprits. Moral: Don't steal from libraries. We're here to help you borrow things for free.",
"The most well-known anti-theft device for books is a tape of magnetic metal strip. The tapes are applied between the spine and the binding of a book (for hard covers) or deep inside in between some pages (for paperbacks). It's called **tattle-tape**.",
"Do you know how if you hold a tuning fork near your mouth and sing the right note, the fork will sing back? The books contain very thin \"tuning forks\" that look like stickers. The scanner you walk through emits a tone that causes any near by \"tuning forks\" to ring at that same frequency. The scanner then listens for the resonating forks and sounds an alarm if it hears any. You can't actually hear the frequency though because it is done with radio frequencies. Edit: It occurred to me that I didn't actually answer ops question. Basically when you check in or out the book it runs over a large magnet what wacks the tuning fork into and out of tune.",
"A lot of books have the metal inserts in their spine or in their cover where you can not see them. But it is not unlikely that the scanners are unable to pick up on every book, just the most valuable ones which have the metal inserts. The way these work is tha the metal inserts are in a perfect length to create a magnetic resonance that precisely matches that of the scanner. So when you walk through the scanner the magenetic field makes the metal inserts resonate which can be detected by the scanner. However during the checkout they use a magnet to change the magnetic characteristics of the metal insert and therefore its resonance frequency. This prevents it from triggering the scanners. This is also a reversable action so they can reset the books when you return them.",
"Oh, they have them. You just aren't seeing them easily, or they're outright hidden. There's a few ways they can mark the books. A common one is a microchip. However, they can also use a sticker (sometimes looks like a circuit) or even slide strips into the spine or under a book jacket without them being visible. These then can respond to radio or magnetic signals from the scanners, and they have some kind of code read by this device that says what the book is. The strip may also be able to be programmed to say if it is checked out or not; otherwise, the code will need to be compared to the code in the system and the status listed there. If the code says it isn't checked out, then it sends an alert.",
"My library has RFID tags (the stickers usually attached inside the cover) that uniquely identify all items. When you check it out the system then knows that specific item is borrowed and therefore to ignore it when it goes past the scanners.",
"In highschool i took the security tags out of a few xboxgames i got at the bargain bin and i stuck them under the cart for the projector, and for a few weeks every time someone rented a projector the alarms would go off",
"I think they have some sort of magnet, I used to work in my high school library and before we checked books out to other students we had to rub the binding against some metal... demagnetizing block? Thing? Edit: after reading the comments I finally understand what I was even doing, 9 years after the fact 😌",
"I used to work at a library for many years. One of my jobs was to put this tape along the inner binding that was magnetized. When a patron brought the books to the counter to check out we would rub them on this metal plate to demagnetize them. When bringing them back in we’d run a magnet along the binding to reactive it.",
"The library by my place uses RFID. You scan your card and just throw the books on a conveyer belt. It's weird to not talk to a librarian, but it's very easy. I wish my library was more like the old ones I went to back in the day. Dusty shelves, weird alcoves, big wood tables, comfy chairs. A nice old Carnegie library. Unfortunately, they're all modern in my area. Way too many new books, not enough oldness."
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lyispi | How do the wave making machines at pools work | Technology | explainlikeimfive | {
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"Pretty simple, really. They have a mechanism that moves large pieces in the bottom of the pools, like the floor or a section in the back. The faster they move those sections, the more energy is put into the water, and the bigger the waves. It's just like how you swish your arms around in a pool or bath and a wave generates. Your arm is only a small mass, so your personal waves are tiny and don't go far. But if a line of fat people were to start jumping up and down in time with each other, a larger wave can be made.",
"This video is pretty great at showing how the Disney water parks do it. URL_0",
"Big part with big piston pushes water with a lot of force at a certain speed. Each push is a wave. Slap your own butt, watch it ripple. Same thing.",
"One possible design: Behind the bars of the wall of a wavepool is another, shorter, thinner wall. The bottom of it is anchored to the bottom, while the top of it moves forward and back like page in a book. A mechanism like the one that can be seen on the side of train wheels keeps the top of the board pushing back and forth."
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lyjvhy | Cryptoart and NFT being bad for environment | I tried to read an article and google, but I still don't get it. Also, as a freelance artist should I make this? Is this a fad? Is it like pixel art? | Technology | explainlikeimfive | {
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"> Is this a fad? Probably yes, it is certainly a bubble. But it will probably stick around like a bad rash like cryptocurrency. > Is it like pixel art? No. > I still don't get it. It is “art” where ownership is secured by blockchain. Blockchain is a kind of database that is structured as it sounds, in a linear chain of blocks. Each block has a cryptographic hash which relates to the preceding block, meaning a chain of transactions can be verified without any central authority. The way it does this is extremely wasteful. The cryptographic hash is a mathematical process which is easy to do one way but extremely difficult to do the other direction. Anyone looking at the blockchain gets the easy side of the equation and can verify all the hashes are correct for each block in the chain. But how do you add new blocks if figuring out what the next hash should be is so difficult? You guess. Or rather a lot of people guess, over and over, billions of times a second until someone finally hits on the answer by chance. They then publish this new block to the entire community of independent blockchain peers who all easily check to see the hash is correct, and update their chains with the new block. As this happens over and over the blocks add up, and the most legitimate chain is considered to be the longest one. If someone wanted to alter the chain they would need to be able to figure out the cryptographic hashes for not just the block they wanted to change but also all the following ones, enough to get a chain longer than the current length. That would be prohibitively difficult since there are lots of people already guessing on the current end block so you would need more computing power (guess faster) than the collective group of people guessing (“mining”) on the chain. On the plus side this is a way of verifying a chain of events (such as ownership of a piece of art) without any central authority to keep track and in a way essentially impossible to alter after the fact. With thousands of independent records and a prohibitive calculation barrier it is effectively impossible to change and extremely secure. Unfortunately it also is killing the planet. All those people who are “guessing” for that hash solution are using computers to perform huge numbers of calculations, spending electricity to solve pointless math problems hoping one is eventually going to be correct. Imagine for example that you bought a painting. What is unique about this NFT painting is that when you buy it several people around the world light campfires specifically for your painting. They are going to keep burning those campfires, consuming fuel, *forever* because if those fires ever go out people won’t be sure who owns that painting anymore. This is essentially the same thing which is happening with bitcoin or any other blockchain cryptocurrency, it is a currency where each unit of currency starts several of those eternally burning fires across the world. Someone decided “Hey, what if we made a new system of currency which depends on and financially motivates the creation of an endless forest fire!”",
"Crypto \"mining\" eats up an absolutely absurd amount of electrical power. It's bad for the environment because it is create a huge demand for extra electrical generation."
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lyrb97 | How does a polygraph measure whether someone is lying? | Technology | explainlikeimfive | {
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"They don't. It measures things like breathing rate & pulse. It only detects their body's functions. They ask questions to which the individual is instructed to tell the truth or lie so they can calibrate it. Loosely they watch for an adrenaline reaction when someone lies. Genuinely believe the lie, It won't work. Cause yourself pain when telling the truth it muddies results. Operators are what matter and even then nothing is definitive. Polygraphs can be beat, give false readings, or be interpreted incorrectly.",
"Not very well. It measures emotions like surprise and fear, which some liars are feeling, but other liars just don't have feelings like that.",
"Polygraphs measure many common signs of stress. The person running the test assumes that stress responses mean that the subject is lying. That's total nonsense, of course. Polygraphs are useless as evidence in court because they're laughably unscientific.",
"Honestly, if you resist taking one, they assume you are going to lie. A lie detector is slightly more accurate than flipping a coin to decide if someone is lying. Their purpose is intimidation.",
"It measures things like heart rate, perspiration, and breath rate, all of which *in theory* will change when someone tries to be deceptive. They begin the test by asking simple yes/no questions (\"Are you X,\" \"Were you born on Y,\" \"Are you married,\" etc) to establish a baseline, then monitor your vitals to see how they change (increased heart rate, faster breathing, and so on) to indicate you may not be telling the truth."
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lyw998 | How are so many bits stored in a terabyte hard drive? | If I understand this correctly, a terabyte has 8 trillion bits. What amazes/confuses me is how we can fit *8* *trillion* individual little switches on such a small space and on top of that, accurately read data from it in the blink of an eye? I've tried my best to look into the topic online but can't find any (helpful) answers as to how these bits are actually being placed where they need to be. | Technology | explainlikeimfive | {
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"Different for HDD and SSD. HDD is just a very thin magnetic layer, the trick is to magnetize just a very small area by applying a short impulse of magnetic field with your read/write head. So it's pretty much like a CD, a bit is like a tiny \"hole\" but it can be overwritten. SSD is made like a CPU. Very tiny switches in nanometer size are \"printed\" on the silicon in the photolithographic process. In short you put photoresist on it, place a foil printed copy of your circuits above, shiny light on it to harden the photoresist, remove nonhardened photoresist, shoot conductive material on it whereever the photoresist doesn't prevent it. There are a bunch more details, but that fills a lecture and not an ELI5 post",
"There are two main storage systems today: Hard Disks (HDD) and Solid State Drives (SSD). Hard Disks are simply disks on which we deposit some magnetic dust which you can imagine to be organized in concentric circles. To read or write from this disk, there is a small arm with a magnetic tip that can be moved around. In this structure a bit is represented by a small stroke of a circle, so a tiny magnet in some sense. Since you’re more interested in bytes, a byte will be a line of these tiny magnets. Just like you number the pages of a book, you number the bytes to give them addresses in order to be able to know what you’re reading or you’re writing. So, from the outside, you ask “Can I read address number 1024?”, and the device moves the tiny head over the corresponding byte, reads the orientations of the tiny magnets and interprets them as 1s or 0s. Writing is basically the same thing, except that instead of reading, the magnetic tip magnetizes and turns the tiny magnets to write the data you wanted. Today we are able to make these magnets very very small and that’s how there are so many bits. ___ SSDs, instead, are directly made of transistors which, like you said, can be seen as switches. The special thing about these transistors, though, is that you can make them “get stuck”: a transistor which is stuck won’t turn on even if you try to. Explaining how the transistors are actually organized and why goes beyond ELI5, but imagine they are in a grid and, in this case, a byte can be 8 consecutive squares of a grid. When you ask “Can I read address 4096?”, your SSD tries to turn on the corresponding transistors, but some of them may be stuck! So only those that are not stuck will turn on, and will output a 0. The ones that don’t turn on output a 1, so you can directly read these signals. Writing consists in forcing transistors to get stuck or freeing those that are stuck according to the data that you want to write. It is interesting to know that this process slowly damages the transistors, and that’s why SSD have a fully fledged tiny computer inside of them that manages the internal structure to prevent you from overwriting the same region over and over again. SSDs are very dense because transistors can be immensely small, we’re talking about being a few nanometers long. ~~Remember that silicon atoms are 0.2 nm big, so we’re talking about having a thing as long as 50 silicon atoms!~~ I was wrong here because I should have considered the silicon lattice constant (the distance between silicon atoms in a crystal), which is instead about 0.5 nm. Even more impressive because there’s even less atoms! SSDs are also much faster than HDDs because HDDs are based on moving parts, but however fast you can make them move, they are still going to be infinitely slow with respect to the speed of electronics. Edit: fixed silicon lattice constant"
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lyzq21 | What the heck is Cryptoart? | I feel so dumb cause I've been reading so many explanations about it but I just can't seem to get it! | Technology | explainlikeimfive | {
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"I'm going to skip all the math because it's not really important and other people have done really good explanations. Cryptocurrency works a lot like regular-cash-currency - if you have some, nobody else can take it from you without you spending it, you can easily transfer it to someone else, etc. And also like cash, it's *fungible* - my \"1 bitcoin\" functions exactly the same as your \"1 bitcoin\", and if I want to, I can divide mine into any size fraction I want to, and it's still all the same. There are other valuable items that are \"non-fungible\" - they're unique, and they can't be divided or reproduced without fundamentally changing them. Art is a good example - a rare painting that is worth 10 million dollars can't be split in half and sold to 2 people for 5 million each. We've now come up with a way to do a similar thing with math, just like we did for cryptocurrency - we can make \"Non-fungible tokens\" (NFTs) that serve as a sort of \"certificate of authenticity\" - you can only make one once, and you can prove that it's yours, until you transfer it to someone else - and now it's theirs and not yours. People are now experimenting with using NFTs to trade digital art. It's like buying the Mona Lisa - lots of people have photos or reproductions of the Mona Lisa, but only the Louvre has *the* Mona Lisa."
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lz1kr7 | how is my electronic device able to control the flow of electricity to parts such as camera without there being actual physical switches | Technology | explainlikeimfive | {
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"Transistors are electronic switches, when you apply a voltage to them they allow current to flow. This means you can use electricity to control how electricity flows, by connecting transistors together you can use them to do logical operations and eventually mathematics, this is basically how a computer works.",
"There are things called transistors, and they have three wires. One is the input wire and current flows into it. One is the output wire and current flows out of it. The third wire is the control wire. If power is supplied to that wire, the switch is \"on\" and current flows through. If not, the switch is \"off.\" These transistors are everywhere. There are tens of billions of them in your phone's CPU alone."
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lz2fql | The "buzz" sound happens when you got phone near your speakers and someone is about to call you. Why does the sound sometimes happens even if noone is calling you? | Technology | explainlikeimfive | {
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"Phones regularly communicate with towers to know what they're in range of. Sometimes you can be within similar range of 2 towers and your phone will switch back and forth. I havent noticed this sound since pre-3G services were discontinued in Australia. Why you should believe me: Its an educated guess, I could be wrong.",
"A speaker uses an electromagnet to make sound. This happens because electrical signals induce a current in a conductor like a wire. Current induces a magnetic field that causes the speaker to move relative to the permanent magnet, because magnets repel and attract. Your cell phone uses radio/microwaves to communicate. These are both electromagnetic signals, just like light (not relevant). These waves also induce magnetic fields in the wires of the speaker. If the signal is strong enough and at a frequency that your ears can hear, this will cause the speaker vibrate so that you can hear it."
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lza0rn | How can you match up two light switches for one light bulb? | Technology | explainlikeimfive | {
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"Your hallway light is connected to a three-way switch circuit. It uses an extra pair of wires called traveler wires to allow two switches to control a single device. The only way to do what you want is to rewire the second switch and switch the traveler wires."
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lzc06g | What actually happens when a website undergoes scheduled maintenance? Why can’t they stay online to make the changes? | Probably a stupid question, but I’m a stupid person so ;-; | Technology | explainlikeimfive | {
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"It depends on a lot of things. It is rarely the same thing twice. But today you usually only get downtime when something involves a database or storage. I have been part of scheduled maintenance on a website caused by the fact that the station wagon we were loading all the data required to run the website into did not have the power or network access to run the website while we drove across town into another datacenter. You may think modern cloud computing have made away with this but all the major cloud providers do allow you to ship disks to and from them and they will ship disks between their own datacenters. This is the fastest and cheapest way to transfer data but there is some latency to it. That is of course an extreme situation that does not happen very often. But for example the last time I scheduled downtime for a website it was because one of the databases it used had some wrong settings and could not be upgraded. So we had to export all the data and import it into another database that were a later version and also had the correct settings. But in order to get a clean export of all the data in this particular database we had to make sure there were no changes in the meantime. So we had to shut down the website during the copy. On the other hand since we fixed this problem we will now never have the exact same problem again for this website. So the next scheduled downtime will be for something else."
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lzfbua | How do noise cancelling headphones/earphones work? | Technology | explainlikeimfive | {
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"There’s electronics inside that listen to the ambient noises around you, then they do what’s called phase cancellation where it makes a sound similar to it and puts it out of phase. The two noises then cancel each other out creating silence. Phase cancellation is wild but really cool",
"There's two types of noise cancelling. Active and Passive. Passive noise cancellation just means the headphones are designed to try and *physically* block sound from getting in. Just like covering your ears with your hands when there's a loud noise. Active noise cancelling /u/TheTalmidim explained better than I can. But, often active noise cancelling and passive noise cancelling tech are used together for maximum isolation.",
"Sounds moves in waves. A wave has a peak and a trough. Basically just a big up and down squiggle in the air and the \"zero\" is a line right down the middle. So part of the wave is above the line and part is below it. The part of the wave above the line is trying to push air up and the part below the line is trying to push air down. If the wave runs into another wave one of two things can happen: if the high part of one wave runs into the high part of the other wave their \"up energy\" combines and the peak gets even higher. So two three inch peaks become one 6 inch peak. Same if two parts of the down wave hit each other, they get even lower. If the waves hit a little different though they'll fight each other instead. A 6 inch peak runs into a 2 inch trough you get a 4 inch peak instead. The \"noise canceling\" comes in when you get identical waves. A 4 inch peak hitting a 4 inch trough just cancels each other. They're trying to move in opposite directions at exactly the same speed so nothing happens. What the headphones do is take in external noise with a microphone, wait a fraction of a second, and then replay it into your ear. The exact same sound is coming from the environment and the headphones but slightly different timing. If it's all working correctly, the delay will be just right so all the highs of the environmental wave hit all the lows of the headphones wave. Since it's the same wave then in theory they would cancel each other completely and you'd have dead silence so you would only hear the song or whatever from your headphones and no ambient noise. In practice it isn't flawless so you still can hear a bit usually but a good quality set will help a lot.",
"I’ll take a crack at it! Imagine a pond. There are peaks and valleys of the water as it moves up and down. If you made an exact copy of the pond and inverted it (peaks are now valleys and valleys are now peaks)..then put the copied pond exactly on top of the original. It would be a flat calm pond with no valleys or peaks. This is what the headphones are doing... but with sound waves (which are really just 3d versions of a pond)"
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lzl9yn | Why does task manager close stuff so much faster than normal closing methods? | Technology | explainlikeimfive | {
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"When you use the normal method to close a program it's going to close that program from within the program itself and it's going to run very specific code. For example, in a video game if you were to close it the developer might make it so that you also autosave before it closes. And if it's poorly programmed it might do a ton of other stuff before it even registers that you told it to close. When you use task manager windows kills the application and says to hell with all that extra crap.",
"The red `X` (or `alt-f4`) don't actually close the application. Instead, it sends a signal to the application - roughly similar to pressing a keyboard key. The application will usually then exit, but it doesn't have to. By contrast, Task Manager actually closes the program directly and immediately, bypassing its code altogether.",
"Closing a program normally lets a program finish what it's doing, and close on it's own time. So if you close Word without saving, it has the chance to say \"hey, do you want to save before closing?\" Task manager takes away all the resources the program was working with, immediately killing the program without it being able to respond"
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lzsuwt | Cloud-native applications. | Technology | explainlikeimfive | {
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"Depends slightly on context mostly a buzzword. If you see it as a consumer it could mean anything from it doesn't run on your machine to developed specifically for the cloud. In a technology sector (think your a developer, engineer, or operations guy looking for a job) it generally means that it is developed specifically to run in one of the specific cloud environments such as AWS or azure. Less often it will just mean the company doesn't have their own servers but is cloud agnostic ie switching from azure to aws wouldn't be hard, generally this means docker containers."
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lzt806 | If the Ancients (Egyptians, Greek, etc.) figured out so many things about the world, why did it take figuring them out again to give them proper credit? Why wasn’t there progress based on the fact they figured it out? | Technology | explainlikeimfive | {
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"There were progress being made on their discoveries all the time. It was just slow. There is a continuous line of discoveries from the Egyptians, Babylonians, Greek, Romans, Egyptians again, Arabians, Italians and eventually spreading out throughout Europa. So for example a geometry textbook might first mention something the Babylonians figured out before telling you what a Greek philosopher managed to find out that built on this and then go on to what an Arabian philosopher managed to quantify from this and then on to how the Italians invented a standard notation for it. And you have similar stories with any discovery in most fields of science. They took thousands of years to develop with progress being made all the time by whichever empire had the resources to hire philosophers at that time. What happened was that a technique called movable type printing press was developed in Germany at a time when Italian city states rich from trade hired a lot of artists and philosophers. This meant that you no longer had to hire a philosopher to go to the only place that had a big collection of these ancient books to study. They could not quickly copy the books and every little kingdom and city could have their own library. So when a blacksmith wondered if he could improve his workshop by installing some sort of automatic hammer he could go to the local library and look up books of famous Egyptians, Arabians or Italians depicting various different mechanisms that he could build for himself.",
"First of all, \"the Dark Ages\" are an invention by 16th century Italians who had a fetishistic interest in Greco-Roman culture and wanted to feel smarter than their grandparents. Plenty of things were developed during the Dark Ages, including windmills, gunpowder, three-field crop rotation and the Gothic arch. When considering humanity as a whole, progress has been going on pretty much the whole time, it has just been slow, for a lot of reasons. Agriculture. When 90% of people have to work in the fields to keep everyone fed, there aren't very many people with the time, resources and inclination to think smart things. Skills. Literacy has not been a common skill anywhere at any point in history (though it was not as rare as some people would have you believe), and a career in being smart would require you to pick up that skill along with at least one new language, instead of doing something more productive like farming. Access to writing materials. Before the invention of wood-pulp paper, writing materials were expensive. Before the invention or adoption of rag paper, writing materials were expensive as balls. This led to only the bare minimum of things being written down and preserved, and things that were considered self-evident or uninteresting were ignored and therefore lost. Skilled labor: Before the invention of printing, the only way to get a book was to copy it by hand. Before the invention of moveable type, the only way to print a book was to get a good woodcarver to carve an entire page, mirror-flipped, into a block of wood. The amount of skilled labor involved, and the cost of buying said labor, in spreading texts meant the movement of knowledge was slow. Lack of contact. Ideas spread and gain traction through trade and exchange of ideas. Some things that appear in isolated places simply didn't leave. For example, none of the Mayan's advances in astronomy ever made it to Europe, and Americans re-invented oil drilling in the 19th century in a way that had been common in China for almost a millenium. Lack of supporting technology. A lot of people look at [Heron of Alexandria's Aeolipile]( URL_0 ) and say \"Oh, if only we could have built on that, we could have had an Industrial Revolution around the birth of Christ!\" Well... no. In order to build steam engines, you would have needed to be able to mine and smelt metal on a scale which would make the materials cheap (which didn't happen), make fuel cheap and abundant (which it wasn't, coal wasn't a thing and deforestation was already becoming a problem in much of the Roman Empire), and make the machines in general so cheap to run there was an economic advantage to using them over slaves or animals (which, because of the above, didn't happen). And that's not even touching on the amount of engineering that would go into turning what was, for practical purposes, a glorified executive's toy into an economically viable source of power. Lack of supporting knowledge: A lot of times, the theories we deride as \"primitive and stoopid\" actually make perfect sense, given the source data. Take the miasma theory of disease, for example. If the observational data you have is \"Touch stuff that smells like shit, get sick, hang around stuff that smells like shit but don't touch it, get sick, stay away from stuff that smells like shit, don't get sick\", the leap to \"smelling things that smell like shit makes people sick\" is a significantly shorter one than \"parasites we can't see are jumping onto us from the things that smell like shit\". It is also way more useful as an explanatory model than \"sometimes gods make us sick\". Scientific arrogance. It's a lot easier to proclaim yourself smarter than dead people than to actually check what they got right and what they didn't. Scientists are also just as status-conscious and prone to insult-trading and slapfighting as anyone else, and a lot of times the proponents of an old theory have to die off before a new one can gain traction. Good ol'-fashioned racism. The British spent a century inventing conspiracy theories involving Atlantis and the Jewish diaspora instead of admitting that it was possible black people built the grand cities of central Africa like Great Zimbabwe. The Chinese insisted that China was the most advanced civilization in the world and had nothing to learn from the outside world until the British Empire showed them the hard way that they did and kicked off what was known as the Century of Dishonor in China. Genuine losses. While the importance of the Library at Alexandria and the Baghdad House of Wisdom are generally overstated, some bits of knowledge were genuinely destroyed and needed to be re-created.",
"All that knowledge was only for the elites. Most people in most cultures would have been completely illiterate. Imagine if all the knowledge of a culture was aggregated into a small college campus. If there was a generation that didn't really care about a certain subject, that subject would stagnate for a hundred years. And how often would you come across someone who actually digs into a subject? Even more rarely would you come across anyone trying to upend conventional wisdom. And worse yet, when there was a serious war, one side of nobles might be completely eliminated along with their knowledge of a subject until someone from the winning side decided to research the old archives. In some cases as with the ancient Mycenaeans losing literacy in a certain language meant that huge amounts of that cultures knowledge would be lost until it was rediscovered by someone new. That was the norm for all of human history until the enlightenment. Advancement was extremely slow.",
"It probably had a lot to do with the fact that the major political authorities would collapse without having tried to share much with neighboring empires - the fragmentation and fall of the Roman empire, for example, left much of europe in near complete disarray, and the resulting groups were probably more concerned about survival than technological advancements. The same likely happened with Egypt and several other of the middle eastern empires. I'm no historian but it seems like the middle east in the ancient days was conquered and reconquered every few decades",
"Many important Greek works were rediscovered during the Italian Renaissance, like [Aristotle]( URL_0 ) and some [Plato]( URL_1 ) and others. This had an influence on humanism and led to a new emphasis on the Greeks. After this, Greek became an acceptable language to study; very few people in Europe knew Greek before the recovery of Aristotle. Egyptian hieroglyphics were never well known in the Western world, not even in the Roman Era, but we started really deciphering them in the 19th century. With that said, everyone knew the Egyptians and the Greeks were lit because the Romans would write (in Latin) where their ideas came from (e.g. this theorem is from Pythagoras, this philosophy originates from Zeno). They got credit in that since, but they weren't as emphasized as the Latin works. Another thing. Before the advent of the printing press, you required a certain amount of political development and social trust for knowledge to really proliferate. No one is going to be putting their head down in books if they're constantly being invaded by neighboring armies. It's not worth the investment. The monastery system and Christianization of Europe helped here *immensely*. Scandinavia only became properly Christian around 1000, and that's a big deal because in 800 you had Vikings raiding and pillaging monasteries, not to mention the Muslim Empire in the South raiding and pillaging monasteries. So with all of Europe Christian, and insulated from outside threats, and with monks being off limits for killing sprees, the monks were able to travel and share ideas with a level of safety and security that is historically unprecedented. Much of the rediscovery of ancient works were the result of monks and priests, almost all of it actually, whose entire existence was putting their head down in books, translating, learning ancient languages, and shooting the shit over brewskies, naturally leading to creative discovery.",
"I think a lot of it has to do with the internet. Now that I can get live info from hundreds of miles away to the point that I can trust buying and selling stocks, any new research is instantly global and available to everyone. Before, if Aristotle, one of the timeless great minds of his time, thought of something, that information was probably only available to the wealthy elite and also likely wouldn’t leave the country for years."
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lztlau | How do software bugs and glitches develop over time if there is no organic matter? Does digital, intangible software also suffer from "wear and tear"? | Always seemed weird to me that perfectly functioning software can develop a glitch or an error over time, what causes it to degrade? I just don't understand how something intangible can become corrupt or broken over time. | Technology | explainlikeimfive | {
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"Software glitches rarely develop over time. It usually just takes time to discover them because they’re often only replicated in certain circumstances. The problem is that in the process of fixing glitches 1 and 2, you may have created a slight change in the software that leads to a 3rd glitch that doesn’t get discovered for another couple of months",
"Hi, there are a couple of things, that can cause bugs in the late lifecycle of a software: 1. The bug might have been there all along, but didn't impact, because it needed a specific situation to show up. 2. Software is rarely shipped and left alone. Usually there is a process of continous improvement, which means a lot of changes over time. One of these changes might break previously working features. 3. Most software will use external APIs and libraries. Even if the software itself doesn't change, changes in those external dependencies can break features. 4. Something might have accumulated over time until it reached a point, where the software can't cope anymore. Think amount of data, that can be processed or number of daily log-files, that can be written. Hope this helps.",
"Glitches/bugs are either mistakes in the original code or don't account for all possible situations. It doesn't wear out over time- it was always going to happen under the right circumstances. Like, imagine I told you that a number plus another number will always result in a larger number. You would be right until you ran into 0, which would break the original logic, or if you ran into negative numbers.",
"Software doesn't exist alone - it interacts with operating systems, other software, data, and users. All of that can change and thus reveal a weakness that was irrelevant before.",
"There are three main causes 1. Software that is heavily **stateful**, has a lot of internal state changes that can build up over time, can get into configurations that don't run right (this is why, for example, Firefox asks you if you want to \"refresh\" it if you haven't launched it in many months) 2. The ecosystem around it changing, assumptions that were made when the program was written no longer holding (this can be anything from OS-level library support \"evolving\" underneath it, to cryptographic primitives being more breakable than they used to be.) 3. The software _itself_ changing, via updates which cause it to run slower and gain bugs it did not have before",
"Most points were already mentioned. One that I want to add: Humans think linearly. So software is used linearly, and it is programmed with linear thinking. Which means that there is usually a start to the interaction of the software and a process that programmers envision the user going through. Which in turn means there is probably also a very linear process to how the software is tested. There is a constant rate of error even the best programmers have. So as you as a user navigate the process, with every interaction with the software you are rolling the dice anew. It's possible that the first roll already uncovers a bug (which was always there, you just didn't see it). And the more often you role the dice, the more likely it gets that you run into one of the errors.",
"I was only really able to comprehend programming when I started playing lots of factory games. You make 1 section correctly. Cool, you move on, you make a second, a third a fourth. Eventually you're on your 28th section. Wait a second....something doesn't add up. Looks like you missed a small piece on section 15 a while back. That error bled into other sections and now you have to redo section 15 and reset everything after that to get it to work right. I know it's not actually the same, but basically a system starts as really simple like 2+2. But eventually after tons and tons of calculation the reallllly small simple error you had in your programming, or redundancy or whatever, gets noticed because it's amplified by the rest of the program. They are complex natural systems that grow until they are so complicated that rare occurrences happen which don't always yield a good result!",
"It's not degradation or a development. It's more than likely that something in the code, a specific set of conditions or amount of data or whatever, is exposed or found. There is no wear and tear in code but there is data moving to and from. A lot of times, let's say in a game, a bug or glitch is just a specific set of things happening that expose something in the code that is undesirable. Sometimes they go unnoticed bc the quality assurance and testing sizes are almost always smaller than the millions of people using it in the public. So that could be part of the reason it seems like a problem develops, when in reality it gets brought to light either by the user inadvertently painting the software into a sort of corner, or the incoming data causing an issue of some kind. But the data part would still be a fault of the software, as it should have been compensated for during testing for it's specific use",
"Usually it's obscure bugs that only get noticed in extremely specific circumstances that just don't come up in regular use. Then one day you need to use a particular feature in a way you've never used it before, and bam. Example: I had a client years ago who had done all their accounting on an Apple IIe for like 20 years with a piece of software that had never been updated. They ran into a bug they'd never seen before in all their years of using it, because they were doing something different than they normally did. It was a fairly simple piece of software, written in BASIC, and the code was visible/editable so I went hunting. I managed to find a simple math error in a piece of rarely-used code and fixed it, and they never had another issue. Hardware breaks down over time (entropy), but software stays the same. I'm sure over very long periods of time the magnetic media degrades, but it's almost always the case that the electronics will fail first."
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lzv5ti | What is the purpose of "buying" tweets ? Purpose of "owninig" NFTs? | You are still using it "digitally" (i.e seeing it digitally after buying) so why to spend money on it rather than just save those as images if you want on your computer ? | Technology | explainlikeimfive | {
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"There’s no purpose except enjoyment. The point is to make a digital version of baseball cards. Because there’s no scarcity in the digital realm, these companies hope that by releasing a limited number of tokens, the tokens will be seen as collectibles. So, for instance, with NBA Top Shot, you buy packs and get several highlight plays. Sometimes, you get a rare one. There’s a market place where people can trade them and buy/sell them like any collectible. I don’t really personally get why anyone would participate. But it’s apparently fun for some people who are really into collecting things."
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lzzre1 | How is hydrogen (fuel cell?) used as a fuel source and why isn’t it more widespread? | I’ve been looking into renewable energy and other options relative to nuclear (not a big fan because of the waste), solar, wind, and thermal. Hydrogen fuel cell technology has popped up a bit and I’m wondering how this works. With my basic understanding, hydrogen is used as input and water (two hydrogens and an oxygen) are the output. How does this reaction happen? Is it not widespread because it’s energy intensive? If not, why haven’t more industries adopted this technology? If so, why is so energy intensive and how much energy does it produce? What’s holding us back from going balls deep into hydrogen fuel cell technology when the by products are clean (even usable) and the input is so abundant in the universe and on earth? With the abundance of input material, It seems like this technology could be useful once we get to Mars as well. Disclaimer: This isn’t for a class or anything. I’m a 31 year old bioinformatician just looking into a new interesting topic and wanted some context from someone with more knowledge. | Technology | explainlikeimfive | {
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"Because it's not really a fuel source as much of an energy storage system. The hydrogen needs to be created from water using electrolysis, and it will use as much electricity to do that as it would take to make an electric car go the same distance, if not less because of inherent inefficiencies any time one form of power is converted to another and then back to another one again. So on top of that, it's dangerous to have a big tank of highly compressed gas in a car. It's simpler to just store the electricity directly with batteries.",
"TLDR: We can't yet produce Hydrogen quickly or efficiently enough to use Hydrogen as a fuel source for cars. > I’ve been looking into renewable energy and other options relative to nuclear (not a big fan because of the waste), solar, wind, and thermal. Hydrogen fuel cell technology has popped up a bit and I’m wondering how this works. With my basic understanding, hydrogen is used as input and water (two hydrogens and an oxygen) are the output. Hydrogen fuel cells have existed for decades and were in fact used as power generators on the Apollo missions. Hydrogen and Oxygen are pass through the fuel cell where the combine to form water. This process releases an electron which creates an electrical current. > Is it not widespread because it’s energy intensive? If not, why haven’t more industries adopted this technology? It's not widespread because free Hydrogen is difficult to manufacture. Current processes either decompose fossil fuels (which doesn't eliminate our dependence on them) or use electrolysis to break apart water molecules. We don't have the infrastructure or technology yet to make hydrogen on any kind of practical scale. > What’s holding us back from going balls deep into hydrogen fuel cell technology when the by products are clean (even usable) and the input is so abundant in the universe and on earth? We need to find an environmentally friendly and efficient means of produce vast quantities of Hydrogen. Other problems like safe storage and transport are fairly straight forward to resolve by comparison. > With the abundance of input material, It seems like this technology could be useful once we get to Mars as well. Yes, fuel cell technology is very relevant in terms of space travel. Hydrogen is the most common element in the universe and Oxygen is also abundant. It just happens that we don't have access to large quantities of raw Hydrogen on Earth, almost all of it exists as water.",
"I'm not an expert on fuel cells, and the physics is out of my area, but I do know about the limitations. 1. Where do we get the hydrogen? We end up getting it from water, but electrolysis is energy intensive, so no matter how efficient your fuel cell is, it is always hampered by the fact that water is hard to break apart. 2. Where do we fill our fuel cell cars? We just don't have infrastructure yet. It's the same issue with electric cars, but to an even greater degree. 3. Storage Hydrogen is a flammable gas, and the only way to store it efficiently is to pressurize it. That's a bomb. It's not impossible to overcome any or all of these issues, but they are the reasons why we haven't dove headfirst into hydrogen as an energy source.",
"Additionally, hydrogen production is an inherent process of nuclear reactors. Radiolysis reactions of ionizing radiation and water results in H2 production. Should we implement a mechanism to harness that hydrogen, it would be yet another reason to rely upon nuclear power. The “nuclear waste” isn’t a scientific issue as much as a political one. The “Waste” generated from nuclear reactors is actually composed of approximately 95% reusable fuel. Other countries, such as France and Japan, already reprocess the “spent” fuel to make it reusable. A long time ago in a galaxy far far away, Congress arbitrarily decided that the fuel from reactors would be discarded instead of reprocessed (due to “proliferation concerns”). This was an extremely short sighted decision that did not consider the possibility of a federal repository failing to be built. Yucca mountain was the US governments Plan A, B, C, and D. Since it is unlikely to ever receive nuclear waste, we should instead begin developing means to reduce the current inventory of waste. If your primary concern against nuclear energy is the waste issue, you would agree that reducing the waste by ~95% is a goal worth implementing. I will note, I am assuming you are US based (as I am), but the logic behind my response holds universally. Especially since the vast majority of the Nuclear World implemented US strategies on waste handling. My kudo’s go out to those who went against the mold (France, Japan, Finland by my last count. Hopefully More exist)."
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lzzwxm | Why do streaming services care about the number of episodes viewed in a sitting. | I like to have background noise throughout the day which results in Netflix and Hulu continuously asking for me to “make sure I’m still here”. My question is why does it matter to them? | Technology | explainlikeimfive | {
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"Using their service costs them money for bandwidth or whatever. Streaming to an empty room or to a sleeping person costs them more.",
"You have to remember, they have millions of customers. Bandwidth (used to deliver the stream to you on demand,) isn't free. They're trying to make a profit. If every account played forever when someone pressed play, there would be so many zombie streaming devices playing for eternity eating bandwidth with no viewers. It's basically a way to ensure that, for the most part, viewing is done by actual people wanting to view the service - it saves on bandwidth a ton."
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m04nln | If a company or website gets hacked, why does it matter how strong my password is? Isn’t it more important that I don’t re-use a password? | If a site gets hacked, am I at any sort of advantage by having a complicated password, or does it not really matter at that point? | Technology | explainlikeimfive | {
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"Any company worth its salt will store your password in a form called a hash. This is you password scrambled up and reduced in size with math, so it’s near impossible to get your original password back. The standard practice for hackers once they get the hash is to do the same math at all sorts of different passwords to see if your hash comes out. This is the reason you have complicated passwords. More possible different passwords make this so much more difficult. So once they plug the hole in their security, the hackers won’t be able to just log in using your password. They wouldn’t have figured it out.",
"Companies don't store your password. They store a hash of it which is a type of encription(over simplifying I know). Hackers still don't know your password, but they can guess passwords until they get the same hash to find it. If you use a really strong password they will probably never figure it out so you will be OK. But if it a weak password they will figure it our pretty fast. If you never reuse passwords tho, it won't affect you very much.",
"TIL that hash is much more than a delicious breakfast food. Thanks for the great responses everyone!",
"some shitty websites will store your password in plain text. but any good/legit website won't. so if you use the same password in all websites, then yes it doesn't matter how good your password is if the plain text website gets hacked. good/legit websites store the password's hash, which is your password after running it through a bunch of math (ie encryption). since most websites use common encryption methods, then the hackers can reverse engineer what your password is by guessing the encryption method and seeing if they can match the hash. the more common a password is, the more likely they are able to match the hash. so yes, it's best to use a combination of a strong password and also not reusing your passwords.",
"It very rare for hackers to directly get your password. Any decent website doesn't actually store your password; they store a \"hashed\" version of it. This is why when you hit \"forgot my password\", the website has you reset your password instead of just sending you your password: the website doesn't actually know your password. So, if a site gets hacked, and the hackers get the hashed version of your password, they can't actually use it to log in. However, they can try to guess your password, and they'll know they guessed correctly if their guess has the same hash as the hashed version they got from hacking. This lets them try millions of guesses per second, so they'll start by guessing millions of simple passwords. But if your password is complicated, they probably will never guess correctly, because there are trillions of trillions of possible complex passwords."
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m06wbq | What are NFTs, NFT art and how is it possible that someone can make money selling a JPEG or gif that is already viewable/downloadable by almost anyone? | Technology | explainlikeimfive | {
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"An NFT is pretty much a certificate of authenticity for digital items. Let's say an artist paints a painting, and then also sends it to print (meaning you can have hundreds or even millions of copies). But there is only one original, that the artist herself painted with her own brush, even though there are many copies. So why would I want the actual original Mona Lisa when I could just get Mona Lisa printed on canvas and it looks good enough? Sure it's a Mona Lisa, but it's not *the* Mona Lisa that Da Vinci himself did and which is considered priceless. NFT pushes that concept to the digital realm as it becomes more and more common for an artist to use a digital medium, using paint programs to create drawings and paintings. So while there may be many copies floating around out there, there is only one true \"official\" original, and the NFT provides a chain of custody to verify it, since digital copies are perfect replicas of the original data, unlike a canvas print versus actual paint and brush on canvas. This opens avenues for digital art to be treated more like traditional art, for the sake of preserving its value or even just as a proof that it is the 100% unadultered original creation of the artist, not shrunk now and again to conserve bandwidth or run through effects on editing programs to alter details; it is exactly what the artist intended.",
"I only heard about them recently on NPR. Its apparently the digital rights to a digital object. I can't fathom why someone would want to buy an NFT, but some people have enough money to buy stupid shit."
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m0bsyw | What does it mean that Google won't allow third party cookies in Chrome? No more third-party analytics firms collecting data on me while using Chrome? | Technology | explainlikeimfive | {
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"No more third party analytics firms collecting your data *through cookies*. There are a bunch more ways they can identify you though. Also third party basically means \"anyone who doesn't have a contract with google\" wich is basically just them receiving a monopoly on your data"
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m0e71g | What is the difference between digital and analog audio? | Technology | explainlikeimfive | {
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"OK, here's a really ELI5: Sound travels in waves. Tie a jump rope to a fence and wave it up and down; the shape of the rope will resemble a sound wave. Now imagine you could freeze time, and you wanted to build a copy of the rope's shape, but you only had bricks. So, you take your bricks, and start to stack them up under the rope. Some times you'll only need a couple of bricks; sometimes you may need to pile them up 10 or 12 high to touch the rope. After a while, if you step back a bit from your work, you can see how the piles of bricks look *very much*, but not exactly, the shape of the rope. The rope is the \"analog\" wave form, while the bricks are the \"digital representation\". The analog wave is *continuous* - the rope's height above the ground can have any value between, say 2 inches and 4 feet. The digital representation is *discrete* - it can only be 1, 2, 3, 4, etc. number of bricks. It can't be 3.867 bricks. Analog systems capture the continuous wave. The groove in a record - do 5 year olds even know what those are anymore? - is a long continuous wiggle that copies the original sound wave. This is actually fairly simple to do - the first records were made of wax, with the platter rotating while a needle, driven by a microphone, made the groove on the surface. This is an analog to analog process. Digital systems try to recreate the original wave by using standard sized pieces to fill in the space beneath the wave, just as we did with the rope. But how wide, and how tall, should each of these pieces be? This is beyond ELI5, but there was a smart guy named Nyquist who figured out that to completely capture all the information in the original wave, it needs to be sampled at twice its highest frequency. This tells us how \"wide\" the bricks need to be. For example, if the highest frequency in the wave was 4000 cycles per second, then we would need 8000 samples, so our 'bricks' have to be 1/8000 of a second wide. The height of the bricks are is a function of how many digital bits in each brick. If you use 8 bits, you can get 2^8 = 256 levels. If you use 16, you get 2^16 = 65,336 levels. If you use more bits, it makes the bricks less high, so you can squeeze the brick piles closer to the actual wave, and so sound more like the original. Note the digital process requires an analog-to-digital conversion at the input, and then a digital-to-~~audio~~analog conversion at the output. There are some - Neil Young comes to mind - who believe that this distorts and ruins the original recording; others don't notice it. finally, and this is way beyond ELI5, digital techniques like Adaptive-predictive Pulse Code Modulation (ADPCM), use clever math and engineering tricks to get the sound even closer to the original, while using less bandwidth. EDIT: Thanks for all the kind comments and awards. Thanks also to those who corrected the minor errors, and expanded on some of the stuff I left out. EDIT EDIT: To all the longitudinal wave fans. yes, you're right. So am I. A sound wave can be represented as a two-dimensional signal on an oscilloscope, and it was that representation I was referring to. I elided the silly scope reference because it's ELI5.",
"Analogue audio is stored in an analogue (continuous) medium such as vinyl or magnetic tape (audio cassette). Digital is stored in a discontinuous medium such as a CD or MP3. Sound is a wave, so audio information just describes the shape of the wave. On vinyl there is a wavy groove which has that shape, on cassette there is a varying magnetisation of the tape which also has the shape. ~~On a CD the \"height\" of the wave at each moment in time is assigned a value from 0 to 255~~ *~~65535~~*~~. Then at the next timestep it has another value. So the true wave shape is approximated by a sort of stepped shape. See a comparison~~ [~~here~~]( URL_0 )~~.~~ *A digital signal on a CD stores the wave form as a series of values at moments in time, with those moments very close together. Think of a series of dots where if you squint you see the original curve. There are 65536 possible values, stored every 1/44100 seconds, which is all you need to replicate the original sound when you play it back.* So long as there are enough values ~~and short enough timesteps~~ the digital shape is a close enough approximation to the true shape that no human can hear the difference. MP3 and other digital formats go further and compress the audio, so they sort of describe the shape rather than simply approximating it as outlined above. This can lead to distortions that humans can hear (or claim to). You might think that analogue is therefore 'perfect' in a way that digital cannot be. This is sort of true, but any real analogue medium will have physical limitations which add their own distortions to the sound, potentially to a greater extent than good digital audio. *Edit to add: yes I am aware that a digital signal perfectly replicates the waveform up to the desired frequency, thanks for all the reminders.* *Edit 2: alright alright I get it. People have strong feelings about this analogy.* *Edit 3: actually scrap that I stand by my statement that a digital audio signal is an approximation of the original. Sound is not band limited, and does not have finite bit depth.*",
"Analog audio is a continous wave, digital it’s like taking little pictures of the wave, that make it discrete. But there is too much pictures so in most cases you can barely notice the difference.",
"Analog is wiggles. Digital is numbers that say how big and how fast to make the wiggles. Speakers wiggle the air which wiggles your eardrums. So either way, the end result is wiggles. Digital is nice because if you see a messed up \"5\" it can be easy to see it was supposed to be a \"5\" because you know what 5s are supposed to look like. (Real digital signals use binary, but the concept is the same.) But if a wiggle gets messed up, it just looks like another wiggle. So you can't fix errors as easily with analog. This means analog is more susceptible to noise. Digital requires conversion back to analog to make the wiggles for the speakers. Having to convert back and forth is the downside with digital. The faster the wiggle changes, the more numbers per second the electronics have to convert. But modern tech has no problem doing this with wiggles that only change as fast as audio does.",
"Analog is wavy air, and can be stored as wavy grooves. Digital is 1s and 0s. When you want to listen to digital audio, it gets turned into wavy air again first so you can hear it.",
"Here is electronic music pioneer Wendy Carlos on the different between digital and analog audio: \" Digital, of course, is essentially computer data which accurately describes an audio signal. It's easily manipulated and can be copied exactly -- all those ones and zeros, you know. Analog is how we usually describe sound waves, a continuous change of pressure or an electrical signal, what a microphone produces, what we used to record on tape. It's a much riskier way to handle audio, but historically was the method we first discovered. Between the two, don't look for deeper meaning or arbitrary differences. There is a cult of near-religious dogma that proclaims analog sound on LPs (\"vinyl\") to be perfection (what a hoot that is for those of us who used to cut LPs for a living!). They think you have to use special wires and elaborate techniques they don't even understand, and they claim that digital is in cahoots with Lucifer. It's kind of pathetic, based on ignorance and flamboyant cheek. The simple answer for synthesizers or reproduction is: To the listener, it shouldn't matter at all, as long as it sounds fine. If you're a performer, it shouldn't matter at all. If you have a very advanced analog synthesizer and then you have another that is all digital--and you get a lot out of both--fine, use them. On the other hand, digital can, in principle, let you be more precise, with finer finesse and control. Analog runs out at five significant digits of accuracy (it doesn't have infinite resolution), something like that, and there's tape hiss to contend with. If you want to put the money and time into it, you can obsess with digital until you're dead. It's a potential that hasn't often been tapped, but usually you reach a practical limit, there's life for you. Microtonal tunings are a breeze with digital synthesizers, but very hard to do with analog.\" From: [ URL_0 ]( URL_0 )",
"Drawing a wave using Lego vs Pen. You can get more accurate interpretation of the wave using regular lego vs duplo (frequency/sampling)",
"I guess you mean analog and digital recording of audio. Sound is vibration of air (or any medium it travels through). Its properties are frequency (how many oscilations it makes in a second, i.e. how high the tone is) and amplitude (how 'big' are those oscilations, i.e. how loud it is). So, how to record that? In essence, there are three ways: vinyl records, magnetic tapes and digital. Vinyl is the simplest one. Imagine a big membrane that is in the way of those vibration. From the air, the vibrating transfers to the membrane. Now connect a sharp needle to it so it vibrates too. And while vibrating, that needle leaves the marks on a rotating dics. Then you can go reverse and the needle follows the grooves on the record, vibrate, transfer vibrations to the membrane and then to the air so we hear the recorded sound. Sure, this is oversimplified but it shows the important part. Tapes work similarly, but the membrane is not connected to a needle but to an electromagnet. Magnets and elecrticity have a love relationship. When a magnet moves near the wire coil it creates electricity in in. And vice versa, if there is electricity in a coil, the magnet will move. So, as the magnet vibrates it creates a small amount of electric current that magnetizes the small particles of iron oxide on a moving tape. What was a wiggly scratch on a vinyl is now a series of variating little magnets of different strengths. You play the tape by reverting the process: tiny magnets on tape create the electricity in the electromagnet in the tape-player head, which moves the magnet connected to the membrane which creates the sound. Both these systems transfer physical properties of sound into some other physical properties - depth and width of scratch mark on the vinyl or strength of magnets on tape. Now the digital recording... which also goes from the membrane and into electromagnet to transform the vibration into electric current but then that current get measured and stored as a number. As the sound is vibration that changes many times a second (it goes from 16 to 20000 oscilations per second) it has to do quite a lot of these measurements and store a number for each one. For CD it is 44.1 thousand per second, film standard is 48000 and, more often than not, initial recording in profesional environment is 96000 times per second. Difference between this and the previous two ways is that now we don't have one physical property transfered into other but into a series of descrete numbers somewhere in memory of the computer. To store them permanently, you can enrave them into silver foil (CDs and DVDs) or use magnetic disks (hard drives). Magnetic disks use the same mechanism as the audio tapes but they don't record the vibrations directly but the numbers created according to those vibrations. So what's the benefit? (edited this paragraph as it was badly formulated) Magnetic tapes and disks are losing a tiny portion of quality with every reading/listening. Here is the important difference. If you copy analog data from the tape, there will be more and more shhhhhh noise introduced in every new generation of a copy as the electricity makes noise. But the copying of a digital recording is immune to that as each new reading and copying gives the same series of numbers as the original even if the recording is faded or partly damaged. That is because even as the magnetic material wears off, reading of the numbers is the same and when you deal with numbers you have safety mechanisms to check if your reading is ok or even to recalculate a part that is missing (see checksums for more info on this). But eventually the hard disk will fail.",
"Analog looks like the thing it represents. In this case wavy air is replicated by wavy grooves on vinyl, or wavy magnetism on a tape. Digital turns things into numbers. In this case the wavy air is measured at various points and the numbers stored in binary reflective areas on a CD or electrons in flash storage.",
"Audio engineer, here. Something I can finally contribute to on this sub! [This article]( URL_0 ) does a really good job describing the basic process in a straightforward way. \"No matter which recording process is used, analog or digital, both are created by a microphone turning air pressure (sound) into an electrical analog signal. An analog recording is made by then imprinting that signal directly onto the master tape (via magnetization) or master record (via grooves) . . . Digital recordings take that analog signal and convert it into a digital representation of the sound, which is essentially a series of numbers for digital software to interpret.\" **Where an analog recording is similar to the fluency of film, a digital recording is stop motion photography.** Analog audio is an exact representation of the sound, whereas digital audio captures bits and pieces of the signal in ones and zeros (binary). This makes it seem like digital audio is inferior from a sonic standpoint (~~spoiler: it is~~), but digital audio has advanced to a point where the difference is negligible or even unnoticeable to the trained ear, with the exception of a few scenarios (namely heavy gain). Edit: it is my **opinion** that analog audio/equipment sounds better than digital.",
"Analog sound is the ripples on water when you drop a stone into it. They are a physical representation on a medium. Digital audio is a mathematical representation, but done at such resolution that when when played the human ear hears it as clear sound. The current formats and sample rates we use nowadays actually reach the limit of human hearing and our audio equipment. But yeah. Analog is basically a drawing or carving of the sound on a medium. While digital is a mathematical representation when resolved makes the same drawing",
"Actual ELI5 attempt: Analog audio tries to recreate an event using a continuous signal. Digital tries to recreate an event by chopping it in tiny pieces and putting them together again. Think about tying a rope to a post and shaking the loose end - you got a moving curvy rope. Digital will chop the rope into bits and then make a shape like a rope - you get a picture of a curvy rope.",
"Analog is continuous and digital takes little samples. It's like cooling at a picture vs a mosaic. The higher the sample rate of the song the smaller prices you are using for the mosaic.",
"There are some incorrect explanations in the comments here. [A digital signal has the same resolution as the analog to digital converter originally encodes]( URL_0 ). There is no data loss due to \"stepping\" or \"discreteness\" of the digital signal. That video is somewhat technical but has an accurate explanation of the differences- and surprising similarities- between digital and analog signals.",
"The main difference is how the two formats are stored. A digital track is recorded through a computer and played from a CD. Analog is recorded on a physical format and the two popular formats were tapes and vinyl records. Digital is much more clear to make out, while analog is a bit \"hissy\" or \"crackly\" depending on the format a song is being played from. It's also good to note here that analog formats deteriorate from dirt or overplaying, so the typical home record would sound worse than the original studio recording.",
"People here quoted shannon nyquist theorem to say that digital can always replicate analog up to a certain frequency limit perfectly. this is not necessarily true. shannon theorem only answers the 'discretization' problem in analog-digital conversion. in shannon theorem, to perfectly recreate the original signal, perfect(accurate) samples of the original waveform is required. in fact, shannon theorem still assumes continuous amplitude of the sample and only deals with the discretization of time. to argue perfect analog/digital conversion with only shannon is somewhat misleading in my opinion. in practice there is another factor called 'quantization' error. this error is present during the amplitude conversion of analog data to digital and vice versa, due to imperfections in the electronic circuit. due to the presence of this error, 'perfect' digital samples of the original waveform cannot be obtained and the recreated waveform will always be slightly different from the original. this has nothing to do with shannon theorem and is only dependent on how accurate the electronic circuit can quantize the amplitude of the original waveform during the sampling process EDIT if i may add, i think the main difference in digital an analog audio is how the data is treated in the player/recorder. soundwaves are analog signal, and generally microphones and loudspeakers can only deal in analog domain to convert the soundwaves to electrical signals and vice versa the data flow in analog audio is: soundwave(analog)- > microphone- > voltage(analog)- > storage(analog)- > voltage(analog)- > loudspeaker- > soundwave(analog) while in digital audio the data flow is: soundwave(analog)- > microphone- > voltage(analog)- > ADC(sampling)- > voltage(digital)- > storage(digital)- > voltage(digital)- > DAC+LPF(reconstruction)- > voltage(analog)- > loudspeaker- > soundwave(analog) as you can see analog audio is much easier to implement since everything is continuous while digital audio is more complex since it requires data conversion schemes. at the output of DAC, the voltage still has a 'stepped' shape, however due to the effect of LPF characteristics of the following stages(amplifier,etc.)the voltage waveform shape is 'smoothed out' close to the original waveform since the high frequency components are eliminated.",
"I think it's useful to understand the context of why you are asking, as there's something that I think the other answers, which are technically correct, miss. The sound you HEAR is a waveform, always. The device producing the sound waves is \"Analog\" depending on your specific definition of the word and the context. Most of the time this stems from some argument or need to figure which is \"best\" digital or Analog. If we accept that sound waves can be represented by a 2d graph that plots the sound pressure exerted on your eardrum, this is an anlog of that sound wave. If we are talking recording formats, the term Analog has a more literal meaning as well especially in the bygone age of physical media. A vinyl record, like an LP, is a literal, physical analog of the original sound wave. In the groove there are tiny peaks and troughs that that match what the sound wave looks like on that 2d graph of the pressure exerted on your ear drum. It's reproduced by a needle tracing over the physical groove. An amplifier takes the signal from the needle and increases the sound pressure, amplifying the signal. It's possible to do this on purely mechanical level, I.E gramophones, or using electricity. In an electrical system of amplification, the needle is connected to a device that creates a very small voltage when you move it up and down. A speaker that you hear sound from typically requires a great deal more voltage than the needle devices generates, so the amplifiers job in this case is to increase the voltage of the signal from the needle. A speaker is usually considered \"Analog because of the kind of device it is. It is an arrangement of electromagnets that moves the core based on the input voltage. The cone of the speaker is attached to the core of the magnet and produces a sound wave by the cone moving air. The input signal is a constantly variable electrical signal that is faithfully and directly reproduced by the movement of the core. This wave is always sinusoidal in nature. What you hear from the speaker is a sound wave that closely resembles the wave that the records physical \"Analog\" was originated from. In the case of an electrical system like I just described, if you measured the voltage over time at the needle using an oscilloscope you'd see a weak electrical signal, but it would be very similar to the peaks and troughs as the original record. If you then measured the same voltage over time at speaker, it's again a very similar wave as the needle one, and the record one, u this time with a much higher voltage. All sounds simple right? The reason I said SIMILAR wave and not SAME wave is that at each point in the process, noise is introduced. When the record was made, some noise is inherent in the process of doing that. When the needle devices changes the up down movement to voltage there is noise induced into the signal. When the amplifier takes the sound and increases the voltage, more noise is introduced. I'm going to skip over tapes a medium, but the brief story there is that a tape is an analogue of an original wave that uses magnetisim rather than a physical representation as found in a vinyl record. So then along comes \"digital\" processing. Digital equipment doesn't deal with variable state. This is because it's what is known as solid state. Different voltages mean very little to solid state devices. It knows only ON or OFF Not going into that here, but that's where this term come from. In operation, you know the device is either on or off. Speakers are really the opposite of \"solid state\", in operation they might be any almost infinitely variable. They need a voltage that is constantly variable, to produce a reproduction of the original recording. If you store something digitally, at a fundamental level it is all just 1 or 0 in terms of value. The difficulty is, if you want to store a signal that is a constantly variable wave and then reproduce it on a speaker that needs a sinusoidal wave to produce sound, with devices that only know 1 and 0. Well, let's deal with storing the wave first. A microphone is basically like the needle on the record but in reverse. It's a diaphragm attached to a similar device that when you speak to it, it creates voltage. This gives you the original, electrical Analog of the sound wave you want to store. What you do with your digital device is sample the voltage value of the wave produced by the microphone at specific, repeatable points in time. This is referred to as sampling rate. When you do this, you can imagine you don't get a smooth sinusoidal curve, you actually get something resembling a load of steps, but if you trace a line through the centre of each step, you get something that approximates the original wave. The more samples you have, the smaller the steps are and the closer you'll be to the original. The disadvantage of higher sampling rates is the much higher volume of numbers you need to store. You might be familiar with the files that store sound waves this way this way. They are called .WAV files, and they usually take up a lot of disc space on your devices. The devices that perform this conversion are called Analog to Digital converters. Now you want to take your stored wave and play it back on your speakers. You need to take this wave approximation, that is basically what voltage the speaker needs to see at a specific point in time to produce the wave, and convert into the actual voltage the speakers need to work. This is done by a digital to analog converter. In a typical digital music storage system, there's usually an intermediate format, whare the wave is stored in a more compressed format, that introduces some loss of the original wave, with the benefit being that the file takes up less space on disc. This would be an MP3 file or similar. Now with streaming media what's more important is how long that file takes to download to your device. No streaming service will give you WAV files directly, or even the more modern FLAC format which typically requires less space but doesn't lose any of the wave. Your getting an AIFF, an MP3 or an OGG. The specifics of this are not so important, but the reality is that by converting from a WAV or FLAC some of the original wave is lost. This happens if you use a streaming service, or if you are dinosaur that still does MP3 files. Let's break down where some of the perceived issues occur in this set of transactions that make up a digital music system. There is both loss of original fidelity and noise in recording the sound picked up by the microphone when it is stored. When it it becomes compressed so that it can actually be used, either for streaming or stored on a device for playback, you lose yet more of the original wave. When you playback the file, there will be noise and sometimes further loss induced by the DAC. So, If you been following along, you might be thinking, Analog is surely best then, less steps, closer to the original wave\" this is not always true. All Analog systems are susceptible to noise. This can have a serious impact on how good both the recording and the reproduction sound. Many billions have been spent trying too eliminate noise from these systems. It continues, as you must still have a microphone and a speaker to record and reproduce sound. (I'll use reproduce, as you can to some extent eliminate the mic with modern music production where a great deal of the sounds you hear might be generated digitally.) Digital systems don't have an issue with noise. And the \"loss\" of fidelity induced by compression doesn't really have an impact on how you experience the sound. All sound waves have elements that the ear can't actually hear, but when you record the wave, it is stored anyway. Formats like MP3 and ogg are extremely good at getting rid of the bits of the wave that your ear wouldn't be able to hear, even the system reproduced it effectively. There is also the advantage of digital signal processing, which is a process of eliminating noise, and dinner times effects that make the sound better using software. It's only possible to do this in a digital system. It's cheaper and more effective than what is possible in Analog systems. It's also worth considering transmission of an audio signal, A digital signal, whether it's DAB radio transmission, Bluetooth or the HDMI signal from your games console won't get noise induced into it. It'll work, or it won't. It won't be better some days than others or deafen you cos you put your phone too close to it, or because you've got a bad connection or anything else. You don't have to eliminate noise to repeat it between multiple locations. It can even self heal if something does go wrong during transmission using a technique known as error correction. Because the difference isn't really important. Both are a part of a system. What you hear is \"Analog\". You can't avoid that. These days it's almost impossible to consume audio without some kind of digital technology, somewhere in the process, and that's overall a good thing that has made the experience better, not worse."
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m0f04g | How does reCAPTCHA know I'm human just because I ticked a box? | Technology | explainlikeimfive | {
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"It actually record the movement before ticking the box. If your movement are too \"robotic\" (pure straight lines, instant teleportation of cursor, miliseconds reflexes) the recaptcha consider you might be a bot.",
"Robots generally either teleport the pointer or move in straight lines. Humans have tons of tiny vibrations in their movement. If you try to use the captcha on mobile you are much more likely to be asked to tap images.",
"the short version is : it doesn't. the long version is that the tick box isn't \"i'm human\" it's \"allow this web-page to check my cookies\". if your browser has tracking cookies on it, then you've been doing \"human things\", and browsing the web like a good consumer, so there's no verification. if your web-browser has no tracking cookies on it, or has 3rd party cookies disabled, or you just loaded straight into the page with the reCAPTCHA on it, you'll get the stupid \"click the boxes with fire hydrants in it test\"."
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m0fwvc | How do USB Flash Drives store information? | Technology | explainlikeimfive | {
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"Each bit is stored in a MOSFET transistor. A transistor have three terminals. A source and drain for the current and a gate which controls if the transistor will allow current through or block the current. So be charging or discharging the gate we can controll if a signal is allowed to pass through the transistor. But in flash memory we do not want to accidentally have the charge leak out of the gate as we can not constantly be charging up the gate when you unplug it. So we make sure the gate is isoletad from all electrical connections. This does however pose the problem of how you can charge and discharge it to set its value. The solution is literally quantum physics. By manipulating the charges in the transistor and in an additional gate on the transistor using very high voltage you are able to quantum tunnel electrons through the insulating material to charge or discharge the gate."
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m0gzen | How do touchscreens work? | Technology | explainlikeimfive | {
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"Touch screens are essentially a large surface of open electrical circuits. Your finger is electrically conductive so when it presses a part of a screen it completes a tiny circuit and the device registers this as a \"touch\" at that point. In order to register a touch you need a slightly electrically conductive touch-er. This is why any old glove will not register as a touch but gloves with a special \"touch screen\" material will work."
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m0i0yd | How does resolution upscaling and remastering works in retro video games and movies? | Technology | explainlikeimfive | {
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"Imagine you have 5 dots on a piece of paper, in a line. You could take a pencil and draw that line through the 5 dots. Now, looking at your line, you could draw lots more dots on the same line - maybe 50 or 100! A computer can use math to look at an existing picture/shape/whatever and basically compute where to add new dots (ie upscale resolution) - the same as you did with your line and pencil.",
"For video games that are 3D there's nothing that needs to be done, it just accepts whatever resolution it's given. This is because 3D elements are stored as a series of points with lines connecting them. A 1 inch long 3D line and a 1 mile long 3D line take the same amount of space to store because you only need the starting point and ending point to draw them. Since most games used to (and some still do) not make the user interface (UI) independent of the render resolution this can result in tiny and unusable UIs. The UI will shrink as the resolution increases unless the developers account for this, such as using a UI that uses relative sizes rather than absolute sizes. By this I mean a UI element might be set to take up 50x50 pixels no matter what the resolution of the game is. If instead they make the UI element take up a percentage of the screen then it will stay the same size as resolution increases. If the aspect ratio changes though this will still cause the UI element to warp. This can cause things that are supposed to be circles to become ovals, and in the case of 2D game stretch them out. For 2D games all of the elements are set to a specific size unless they use a vector format (this works the same as I described for 3D), but let's say they all use a specific size. In this case when you upscale the image there are algorithms that try to increase the size of the image while making it still look like the original image. None of these algorithms are perfect and you can only upscale a 2D image so far before the image starts getting messed up. For movies if it's film they go back to the original master and scan it in at a higher resolution. Film is a visual format that doesn't have a resolution, the image is stored physically on the medium. Sometimes when they shot on film they knew they were going to only show it on TV so they would frame shots for 4:3. This happened with Star Trek TNG. Just outside the 4:3 frame were the edges of the set, crew members, lights, or other things. Even though they could have made it widescreen they had to stay with 4:3. If it's video or digital they can't do this as there's nothing to scan in. The resulting video output is a specific resolution. Upscaling is still possible, but you can't get extra detail that doesn't exist...or can you? There's a new method called super resolution that uses the magic of AI to upscale the image. Unlike other upscaling methods super resolution can create detail out of nothing. DLSS is a real time implementation of super resolution, it uses multiple frames to intelligently create the output frame. There's many picture upscalers out there as well. It's also possible to do this with video but I've not seen any publicly usable implementations yet."
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m0mlb0 | What is a computer actually doing when it fully deletes a file, and why are some files too big to go into the trash so they have to be "deleted permanently?" | Technology | explainlikeimfive | {
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"When you \"fully delete\" a file, the computer doesn't automatically and instantly do anything - it just tells the hard drive \"hey you can write over that old data with new data if you need to\". That's why it's possible in some cases to recover \"deleted\" files, because... the file's still there until something else comes along and takes its place. As far as the files being too big, that's just an artificial limitation put on the Recycling Bin in Windows. They assume that if you delete a single Word document that you might need to easily recover that later, but if you are deleting a 500 MB installation file for something, you'll probably need that space *sooner* rather than later and you probably *don't* need that file again. You can actually adjust the recycle bin's limit to be bigger or smaller as you want. Making it bigger just means you won't have as much free space on your hard drive when you *recycle* files until you actually manually empty the recycle bin, though.",
"The files are basically moved to another temporary location (it says \"move to recycle bin\" vs \"delete permanently\"). The recycle bin is usually a temporary location inside the drive partition your OS is installed in, and if you're \"deleting\" a file in another location, a file larger than the available free space in your OS partition - it can't be moved to that drive.",
"The trashbin is just a folder that isn't really special except it remembers where the stuff came from before. So files in it aren't deleted at all yet. If you actually delete a file it's space in the memory is just declared empty. So the bits stay, but other programs can claim the space to save their own bits by then overwriting the old files for good"
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m0qvlo | Film is rearranged metal particles on tape which are read by an electromagnet. CDs are discs with burned pits in them which are read by a laser. What makes one analog and one digital? | Technology | explainlikeimfive | {
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"CDs pits represent binary data, on or off. Film's particles (or grain) can be any color, making it analog. A good way to determine if something is analog vs digital is how the smallest unit of measurement can be measured. If it can only be on or off then it's digital, but if it can be on, off, or some value in between then it's analog.",
"Film? Do you mean audio cassette? In any case, the audio cassette if that's what you mean, represents a smoothly varying signal, which corresponds to the magnetic field on the tape. WHen recorded, the audio signal is directly fed into a magnetic head, and that head (which is just a coil of wire) creates a changing magnetic field, which magnetises the tape in a way which directly represents the analog audio signal. There's no converting happening, except between electrical and magnetic. With a CD, what's encoded in the pits and lands is digital data, which has to be fed into an digital to analog converter to turn it back into the sort of signal that can be fed out of a speaker.",
"Digital just means there's an extra step in the middle to translate everything into 0s and 1s. Film uses the physical properties of the metal and clever manipulation of chemistry to store an image. CDs uses a laser and the physical properties of light to store an image, but the image was first translated into 0s and 1s (which correspond to the lands and pits on the disc) Edit: More examples after I saw you meant audio. With a magnetic tape, the soundwaves that were recorded get directly transformed into magnetic fields of varying strength. The tape essentially store \"magnetic waves\" that are a 1 to 1 transformation of the original sound waves. With a cd, those sound waves are first translated into 0s and 1s before being transformed into lands and pits. With out a computer that knows the code, those 0s and 1s are meaningless.",
"CDs are digital because the data is stored in a discrete fashion: binary, 1 or 0. Film is stored in an analog fashion because the data is recorded as a gradient (of brightness, color, etc), so it isn’t discrete."
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m0zrwu | How do traffic lights work? Sensors, timing, connection with other traffic lights ... the whole shebang. | Technology | explainlikeimfive | {
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"At the most basic level, the traffic lights have a pre-programmed controller. The controller tells the light how long to show each colour to each direction. If the controller is a bit fancier, it will allow the program to be different at different times of the day or different days of the week. Most traffic lights have detector loops in the pavement (they look like big black circles.) The detector loops are coils of wire that develop an electric current through induction when the metal frame of a car is above them. The controller would adjust the program for when cars are present - for example you might have a green light that only lasts 10 seconds, but it stays green when cars are coming up to a maximum of 30 seconds. Very fancy traffic lights use cameras instead of coils, and they could be networked with other controllers in the city. That would allow for things like setting up a \"green wave\" for emergency vehicles.",
"Telling this from the perspective of dutch traffic lights (or traffic coördination installations (TCI). We've got pre-programmed and detection systems. Both kinds have detector-loops in the roadconstruction and where pedestrians and cyclists use the intersection pushbuttons for them. The difference is in the way the loops are used. In the pre-programmed TCI the loops are used to determine if a green light sequence can be skipped for a direction, because there isn't any traffic waiting to enter. These intersections can also be programmed to skip pedestrians and cyclists until they push the button indicating they want to cross. The TCI's with a detection system have loops reaching out of the intersection to detect if somebody is comming. Depending on what the TCI/intersection owner wants, this system can have loops for cyclists and detectionsystems for pedestrians added, replacing or aiding the pushbutton. I've also heard about some TCI's having weathersensors added so pedestrians and cyclists get their turns faster when it's cold or rains. Thought behind this is that a car/truck-driver can wait a couple of second longer in their warm and dry vehicle while the others get to a warm and dry place faster."
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m17w2b | Why are circuits on boards? | Technology | explainlikeimfive | {
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"Before circuit boards were a thing, designers had to scramble wires together in a big ugly mess. I don't have all the details of this organization, but imagine a bunch of tangled up wires, capacitors, etc. Circuit boards not only rid of those messy wires, but they're super compact, which allowed computers back then to shrink down (along with other inventions like the silicon transistor). Edit: [I found the image I was looking for.]( URL_0 ) Edit2: With Circuit boards came cheaper computers, which meant they could be mass produced and sold to consumers. Paving the way for today's computers and even the Internet and the www.",
"Because it's way easier to manufacture this way, and therefore nearly all modern parts are designed to be put on printed circuit boards. That wasn't always the case, up to the 1950s point-to-point wiring was common. It looked like this: URL_0 This is basically impossible to automate, and was done on long assembly lines by (typically) women. In those times, labor was cheap and parts were expensive, so this was economically viable. It was prone to faults though, it's not uncommon at all for collectors of vintage gear to find connections not ever been soldered. They just barely had contact to work on the testing station. Then came printed circuit boards. The start out as a copper-clad board and all the copper not needed for connections is etched away in a quite complicated process, which I will not explain here. They started to be used in 1930s, but really became mainstream in the early 1960s. The early board were still populated (parts were stuck through holes) by hand, but already soldered automatically by moving them over a bath with molten solder (wave soldering, still in use today). From the 1980s onwards, even the placement of components was done by robots and then the whole board is put in a special oven to melt the soldering paste which was put on before the parts. You get a finished board in minutes, with a precision not possible by hand.",
"All the branches were taken? Seriously tho, because it's easy to design in 2d (draw by hand) and mass produce with minimal waste and effort. Also it's far more durable and safe than wiring."
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m17y1p | What is exactly happening when AC power is being converted to DC energy? | Technology | explainlikeimfive | {
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"There are electronic components called diodes. These are sort of like one-way streets for electricity. If you try to pass AC through one of these, only half the wave will get through, say the positive half. This is called a *half-wave rectifier*. Now, if you do two of these, one in each direction, you can have one stream that gets the positive halves of the waves and a second that takes the negative half. You can then combine these together using some more diodes so that you basically get the full wave, but with all the negative bumps flipped to positive. This is a *full-wave rectifier*. Sometimes, your circuit uses 3-phase power. There are 3 wires running AC, but ⅓ of a cycle out of step with each other. If you fully rectify this, you get a signal that's just a slightly bumpy version of DC. Regardless of single or 3 phase, the next step is to smooth things out as best you can. This can be done using a *low-pass filter*. LP filters let through signals that don't vary much, and are resistant to quickly changing signals. If you've got a sound system with a woofer and a tweeter (low and high speakers), there's an LP filter making sure the woofer only gets the bass. A simple LP filter is just a coil of wire, known as an inductor. When you pass a current through it, it generates a magnetic field. This field is resistant to changes in the current. It store energy, and when the supply drops, it gives off some of the stored energy to stabilise it. When the current tries to increase, the inductor takes in some of that energy to 'charge up' the magnet. This means the current coming out the inductor will be smoother than what went in.",
"Imagine the energy as some water. Now imagine a big glass of water - something like a water tank full of water with a hole in the bottom with a continuous output flow. This is your D.C. current. Now, imagine that you bury this water tank in the sand on a beach and that each wave that arrives fill it a little bit (and you still have a the water going out of this tank). Well, the waves are you A.C. current entering in pulses in your tank. When an A.C. to D.C convertet is designed, its basically a calculation on how much you can bury your tank in the and the size of your tank (voltage and capacitance value for the capacitors) in order to have a more or less stable output flow out of the tank - also depending on the frequency of the waves arriving.",
"The most important part is the bridge rectifier. We use little electrical one way valves (diodes) so that no matter the input voltage (+ on top or on the bottom) you always get positive voltage on one wire and negative on the other, [the wiki has a nice GIF showing this]( URL_0 ) Generally we will put a big capacitor on the output to store the energy. This capacitor takes the ups and downs that are coming into it and stores the energy so it just sits at the peak voltage. Now you've got a constant voltage that you can use to power things or can step down to a low voltage using a DC-DC converter so you can get 5V for your phone or 3V for a little micro controller. Old style boxes, the really heavy ones, used to put a step down transformer in the front to bring the peak voltage down from 170V (on US 120V power) to the 12 or 24V that they were needing in the end and then they ran that lower voltage through the rectifier and into the capacitor. These are simple and don't require any fancy electronics but they do require about 5 pounds of iron in the transformer core. Electronics are wayyyy cheaper these days than they used to be so its now cheaper to use the fancy electronics for the DC-DC converter than a big transformer meant for stepping down line voltage at just 50/60 Hz",
"This is one of those things that's much harder to explain with just words, so I'm going to invest about a hundred seconds in MSpaint to make some bad images that will help a great deal. First off, DC, or direct current, is electricity that flows in one direction. AC, or alternating current is simply electricity that switches directions on a regular basis. Household AC switches 60 times per second. AC starts out looking like this on a device called an oscilloscope. You can see it smoothly changes from one direction (positive, or +) to the other (negative, or -): URL_0 Using a pretty simple circuit, you can 'cut off' one side and send it all in one direction, so that it looks like this: URL_1 That circuit just uses a few components called diodes, which only allow electricity to flow in one direction through it. The problem is that it isn't very smooth. It's more like very fast bursts of DC current, so we need to try and fill in those gaps. To do that, we use a component called a capacitor. That device is like a tiny battery. When there is current going through it, it charges up. When there isn't, it discharges. We can use these to sort of fill in those gaps, like so: URL_2 The better a job done by the capacitors, the more it looks like a straight line, the closer to pure DC it gets. URL_3 There are more modern ways of converting AC to DC with much more accurate results using transistors, but this classic way has been around for a very long time.",
"You use some diodes and a capacitor to \"rectify\" the signal. They are arranged in such a way that when the voltage is positive, current flows, but current is blocked by the diode when your AC voltage is negative. The capacitor then starts discharging some stored energy it got when the signal was positive, and that keeps your DC voltage constant.",
"AC is electricity that goes from positive voltage to negative voltage over and over again. Each time it does this, we call that a cycle. The number of cycles per second are called hertz. DC is electricity that is always a positive voltage. There are 2 components you need to know about to converting AC to DC. The first is called a diode. A diode only allows electricity to flow one direction through it. Since AC voltage goes positive to negative, the current flows backward and forward. We want to stop that. The second component is a capacitor. More on that later. So, imagine a sine wave of electricity, that is AC. The diode chops off the bottom half of the wave, or the negative part. What you have now is like hills of positive voltage with 0 volts between them. This is called pulsing DC. We want to make the pulses smooth, so that the voltage is constant. This is where the capacitor comes in. The capacitor charges and then slowly releases that charge. So it charges up from the pulse of DC and the releases a longer slowly decreasing voltage that bridges the gap between the hills. Its still not perfectly constant, but its much closer to a constant voltage and most DC items don't really care about the noise. Extra credit: there are circuits you can build called full-bridge rectifiers that flip the negative part of the wave to positive and add it to the positive wave so that there is no time when the voltage is at zero and the hills are closer together. This is both more efficient and has less noise. These are made with 4 diodes in a clever arrangement."
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m19zus | What are some of the problems that zinc-ion batteries have, over lithium ion? | I've read in an article that aqueous zinc ion batteries are better, safer, and can store up to 5 times the charge of lithium ion. What are some of the major concerns that has made zinc-ion batteries not so much popular? One thing that I was able to get from the article was that it can last for only 100-200 cycles? Edit: 5 times cheaper. Sorry for the typo, I just skim read that article, while researching on Li alternatives. | Technology | explainlikeimfive | {
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"Where are you seeing this 5 times charge figure? According to Wikipedia (obviously not the be-all and end-all, but still) zinc-ion batteries are around 450 Wh/l energy density, while Li-Ion are between 250 and 693, which is pretty much the same ballpark.",
"(Keeping it simple...) Zinc has long been used as a material for batteries - and very successfully for certain applications. Zinc-Air are extremely common for small button cells as primary batteries. Almost \\_anything\\_ will react with zinc and via ionic exchange produce electricity - kiddies use lemons and galanized (zinc) nails even! The problems really arise with the secondary cell process where there is a need to reverse the process to store energy. Unfortunately much as zinc wants to convert to electricity one way, the reverse reactions are often poisoned or very inefficient, and so the cycle life becomes very short due to this poisoning or loss of reactive zinc. Lots of research has been done and will continue into trying to damp these issues, as zinc is (comparatively) safe, and certainly very plentiful and inexpensive. It also has a relatively low environmental contamination potential compared to other metals. Unfortunately some of the chemicals used in zinc secondary reactions are not so friendly though - such as zinc - bromine secondary cells. Zinc/alkaline/manganese-dioxide battery's are one example of smaller successful secondary zinc batteries, but these too have limited cycle lives for the same reasons as above. I hope this helps. :-)"
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m1ae5t | Why is there significant positional variation in mobile data speeds even inside a single room? | Technology | explainlikeimfive | {
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"Mobile phone signals are typically in the hundreds of MHz to a few GHz range, which means the wavelengths are something like 10-40cm. Objects roughly that size can reflect or absorb the radio signal, causing blank spots and interference (both constructive and destructive) over a range of a few meters. If you're outside with no major things between you and the antenna you shouldn't see much variation, but inside a room with other radio noise sources, potential blocks, and potential reflectors you could have a \\*very\\* complicated radio situation that varies from point-to-point over just a meter or two."
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m1aeqm | Regarding cookies on website: What is legitimate interest and how do companies get the status? | Also, what rights to store cookies do they have when you object to their regular cookies but do not tick off the legitimate interest option? | Technology | explainlikeimfive | {
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"Most companies don't actually do this correctly. There are two different data privacy laws in the EU which potentially govern cookies, and companies get these confused. The main data privacy law in the European Union is GDPR. Under GDPR, in order for data processing to be lawful, it needs a \"Legal Basis.\" Basically, a justification that is legally recognized as a valid reason to process someone's data. There are six (6) possible choices for the Legal Basis for a processing activity. Some of these are straightforward, like \"Performance of Contract.\" If I purchase something from Amazon, they need my shipping address to actually send it to me. Makes sense. Or \"Legal Obligation.\" There's a law saying they have to keep a record of credit card transactions for seven years. Also makes sense. The most open-ended Legal Basis is \"Legitimate Interest.\" This legal basis basically says \"we have a reason for processing your data, and we promise it's a good one and doesn't invade people's privacy too much.\" The vagueness is basically necessary for many businesses to operate, but also the most open to abuse. Fraud Detection is a common example of something that falls under Legitimate Interest and has a reason to exist. Legitimate Interest implies some extra obligations unique to that Legal Basis. For example, the company *is required to tell you the specific Legitimate Interest*. They can't just say \"Legitimate Interset.\" They have to say \"our Legitimate Interest of fraud detection\" or whatever it is. Processing under Legitimate Interest is also subject to the Right to Erasure (more commonly known as the Right to be Forgotten), which is not the case for e.g. Performance of Contract. A company should perform a Data Impact Assessment before invoking Legitimate Interest, and this is reviewable by regulators. If they did a bad job balancing their interests against the privacy of the data subjects, they can be subject to fines. However... Website cookies are *also* governed by the ePrivacy Directive. This law has no concept of Legitimate Interests. Either a cookie is strictly necessary for the website to function, or it requires consent. If a company invokes Legitimate Interest to justify their cookies, then they are violating the ePrivacy Directive. (Due to how EU law works, the ePrivacy Directive has different names in different countries. E.g. in the UK it is called PECR (and is still in effect post-Brexit))."
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m1cn3r | Why exactly are bitcoins solving problems when mining? | What are the use of the solution to these problems. It's just to verify other transactions? So bitcoins are earned from just maintaining itself? | Technology | explainlikeimfive | {
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"There are two uses...one is to secure the blockchain, the \"ledger\" of all bitcoin transactions that ensures that you can't duplicate them. The solution of the bitcoin mining problem is basically a \"key\" that takes a lot of work to find that semi-uniquely identifies a block of transactions and connects it to the prior block (and, through chaining, \\*all\\* prior blocks). \"Semi-uniquely\" because there may be other solutions that also secure the block, whoever finds one of them first gets it and, once the next block is added to the chain, that's the only solution that will work. To corrupt the ledger would require recomputing \\*all\\* the solutions to all the blocks \"downstream\" of where you want to alter it...that's computationally infeasible, which is why the blockchain is considered secure. As long as the majority of the computers mining aren't corrupt you also can't corrupt the current block because they'll vote out corrupt transactions. The other use is to distribute bitcoins...the only way to create/earn new bitcoins from scratch is to solve the problem. This incentivizes people to mine...so yes, bitcoins are earned from maintaining the bitcoin currency.",
"Simple answer: they do seemingly unimportant but heavy work. This makes sure there is a steady and slow supply of blockchain blocks and new coins. This is important because in Bitcoin, there is no central company that controls your transactions and money (aka a bank). Instead the money and transactions are managed by everyone. Because you can't trust anyone and Bitcoin would not be worth anything if everyone could simply create new Bitcoins, Bitcoin needs a system to ensure that it is really hard to do so. This system is called Proof Of Work. With Proof Of Work, the Bitcoin network tells the miners to make a special calculation/puzzle of which the answer is not known, but when solved, the answer can be easily verified. The miners then start calculating like a maniac. Then at some point, some miner finds an answer. Because the answer can be easily verified the network can then validate the effort and reward the miner with coins. Because Bitcoin tries to keep a steady pace of new blocks/coins the network is self adapting, meaning that it can make the puzzles harder or easier, depending on how often a Bitcoin is mined. Right now Bitcoin is super popular and there are many competing miners, so the network makes it is incredibly difficult to solve the puzzles. This is why miners \"waste\" a tremendous amount of energy.",
"Pretty much, it's just an arbitrary calculation to make sure that everyone agrees on which transactions to include in the blockchain and limit the new supply of coins."
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m1fhrf | How is a computer animated movie transferred to film? I'm thinking of Toy Story specifically. 1995 was before digital projection, so how did PIXAR get the final movie onto celluloid? | Technology | explainlikeimfive | {
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"Pixar developed a laser scanning and printing device called PixarVision. With it they can scan film into a computer and also print images from the computer to film. So the entire film was printed onto master negatives one frame at a time",
"If you printed out the individual frames onto cells such as used with traditional, hand-drawn animation, you could then use the same transcribing process as was used for those animations. Takes a lot of time compared to going directly to digital, but so did traditional animation.",
"Digital projection is much older than 1995, it was based on lasers and much too expensive for people. That's just not how it was done. Toy Story was \"printed\" on film, one frame at a time, by a special machine called a \"film printer\" (not super original name). It wrote each pixel in order, allowing the film to record the light in it's natural grain structure. The file was developed, and processed just like any other movie (they were all made using film then)."
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m1fnfq | How does cryptocurrency like Bitcoin contribute to climate change? | I've been seeing lots of articles about how Bitcoin and other cryptocurrencies are leaving massive carbon footprints that negatively affect the climate. But after doing a little research, I'm still not entirely sure how that connection is made? How is crypto more harmful to the climate than actual paper money, or even traditional digital banking? To me right now, it seems like all these Bitcoin = climate change news stories are being pushed by people or organizations that have a vested interest in ensuring decentralized currency doesn't take off. | Technology | explainlikeimfive | {
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"Mining crypto takes a lot of power. As their value increases, and mining success rates decrease, the power investment required to find each new coin increases. The entire currency is based on burning through electricity to do maths problems. It's environmentally awful, whatever else you might think about crypto currencies.",
"> How is crypto more harmful to the climate than actual paper money Because in order to spend a tenner nobody needs to spend multiple kilowatt-hours verifying it. I just hand over a tenner to the cashier and we're done. In order to create a bitcoin block and be awarded with the mining reward you need to guess a very large random number. This requires spending electricity to have (most often) your GPU cycle trough numbers until you find the correct one. That spends a bit of energy but nothing to write home about. The issue is that a *lot* of people want to be the one to find those numbers, so collectively over the network there are millions of GPU's, entire warehouses worth of GPU's, constantly running 24/7 playing at a giant lottery, constantly guessing numbers day in and day out. That wastes a *tonne* of electricity. The issue with electricity is that quite a lot of it so far is generated with fossil fuels and therefore has a carbon footprint. Bitcoin has a lot of benefits, but in it's current form with the current amount of demand it generates it's really wasteful.",
"The \"mining\" of bitcoins and other similar currencies requires high-powered computers running for large amounts of time all using up electricity and generating heat."
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m1hq4c | How do 3d glasses work and what do the red and blue lines have to do with it? | I remember that when I took off the glasses, the movie appeared to be a red version overlapping a blue version, searched on the internet but it was too technical for me. | Technology | explainlikeimfive | {
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"You're able to see the world in 3D because your eyes see things from two different angles which your brain turns into a 3D image. Color filters absorb everything but a particular color. If you look through a blue filter, you'll see nothing but the shade of blue that the filter is colored with. Movies and videos are 2D since the colors/pixels appear in the same place as viewed by both of your eyes. When you cover one eye with a red filter and another eye with a blue filter, you can display a red and blue pixel in two different places which will confuse your mind into thinking it's looking at a single pixel from two different perspectives. When you see the red version overlapping a blue version without the glasses, you're seeing the intended perspective for both eyes, by both eyes at the same time.",
"The \"left\" view is projected in one colour and the \"right\" view is projected in the other. As you discovered, looking at this without glasses looks like a weird, blurry mess. The glasses, though, filter out the other colour - the red lens only lets red light through and the blue lens only lets blue light through. This means your left eye can only see the left view, the right eye can only see the right view and thus you're able to perceive depth. If you put them on upside down it looks all backwards and wrong and will make you sick."
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m1nxp5 | What about using screens is bad for sleep? | I often hear that you shouldn't look at screens 30 minutes before bed to rest your eyes, which makes some inherent sense, but often paired with that is that you should read before bed. Is scanning ~450 wpm really all that different from watching TV? If so why? | Technology | explainlikeimfive | {
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"Screens give off a lot of blue light, just like the sun. Your body uses the light around you to determine when it's time to go to sleep. Too much blue light confuses your brain into thinking the sun is still out and prevents you from being sleepy.",
"It depends on what you're looking at on the screens. Obviously, if you're looking at a screen showing a picture of the sky during high noon is different than looking at white text on a black background. The problem is, blue light which is present in white light, tricks your brain into thinking it's daytime.",
"Blue light suppresses the production of the hormone melatonin, which is needed for sleep and the regulation of circadian rhythm. Blue light in the morning, like from the sky, causes your circadian rhythm to shift earlier and makes you tired earlier in the evening. Blue light late in the evening pushes your circadian rhythm later. Phones emit a lot of blue light. Also, if your system already has a high amount of melatonin in it, it makes your eyes more susceptible to damage from blue light."
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m1ofk7 | Why does it take so long to change a channel on modern TVs? | Technology | explainlikeimfive | {
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"Old TVs were analog. The signal was encoded in a simple way than needed just basic electronics to decode and display. This was fast, so old TVs changed channels quickly. However, such a method of transmission was inefficient: just one TV channel per frequency. It also did not allow for a high quality of image. The only edge of analog signal is that it is robust: it can be displayed no matter what the interference, it will get blurry, snowy or lose color, but it still will be decipherable. Modern TV is digital, it uses complex computerized encoding that allows to pack ten or twenty channels in one frequency with much more quality. However, deciphering this signal is harder and needs a mini-computer that is built in every modern TV set. That's why the slow down: it's the wait while the minicomputer processes things.",
"Television, both broadcast and cable, is a digital signal. When you switch from one channel to the next, perhaps half a second of data from the new channel needs to be processed before the television can begin displaying video and audio.",
"Most digital TV providers use something called multicast to distribute their programming down to customers. This saves them a massive amount of bandwidth, because only one of each packet (think like a frame of your show) is needed on each circuit. Multicast is built in \"tree\" through the provider network where the source (your channel) is the base of the tree and the customers are all spread out like the branches. When you change the channel, you change to a new tree because you are listening to a new source. This takes about ten seconds to fully establish the new tree from the source to your receiver. In the meantime, your receiver sends a request to the source to get a unicast flow of the channel while the multicast tree builds. A unicast flow means the provider creates a copy of that channel's data and sends it only to you. The advantage to this is that this flow can be set up much faster because no tree needs to be built, so you can start streaming your channel in only half a second or so. The disadvantage is this uses much more data in the ISP network, so the ISP wants you on multicast. After the multicast flow is built, your set top box will seamlessly swap over to the multicast tree, and now you will be part of the exact same data stream that your neighbors who are on the same channel have. ELI5: it takes time to set up the ip data flow for your new channel. First, your set top box performs a direct download of the channel for about ten seconds. This means you get a whole new copy of the data from the channel provider that is built just for you. After those ten seconds, you join a \"room\" with your neighbors so that all of you who are on the same channel receieve the data together.",
"Old school analog channels literally conveyed the signal that was being projected onto the phosphor of the tv screen, line by line. There was no buffering or interframe compression, it arrived at the antenna and immediately displayed, pixel by pixel, line by line. At worst the screen had to wait 1 vertical blanking pulse, \\~1/24th of a second to recognize that the newest data referred to the top info on the screen to start drawing the new picture. Then came digital. The data is still streamed in, but it's not just line by line. It's video format encoded, compressed, and often encrypted, then broken into packets of data for transmission. First, the tv has to acquire enough packet data to know what it has received - reassemble the packets to see how tall and wide the picture should be, the framerate, encoding information, decrypt it (if you have bought the channel or not in your package), and then decompressed\\* to an actual picture that can be drawn on the screen. In the case of a cable box + tv, the cable box then has to take the picture it's formed and RE-ENCRYPT it to go over the HDMI cable for copy protection. Only then can the licensed TV with proper HDCP keys decrypt that signal again to have the picture to put on screen. Basically...a LOT of steps have to happen, and each takes time. \\*decrompression - For a very simple example, for a video of a black screen with a white dot moving in a circle, it's more efficient to transmit 'most of the screen didn't change, just this bit with the moving dot needs to be updated/moved/distorted'. The old school method of sending every pixel of every image one after another just won't cut it. Multiply that technique times a bajillion and you have the modern compression algorithms used for video transmission. Uncompressed there would be no way to fit all the HD video and audio streams down the pipe simultaneously.",
"It's because of how the compression works. Analogue TV sends a stream of analogue information. The channel changes as soon as the TV receives a signal saying it's the start of the image. This will tak 1/60 seconds in countries where they use 60Hz refresh (e.g. North America), and 1/50 seconds everywhere else. Digital TV doesn't send every frame in full detail. It sends a key frame, and the next few frames just show the differences. So it has to wait for a key frame. That will happen a decent fraction of a second later."
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m1ofuo | Why do audio mixers have plugins labeled as multiple channels and how are they utilized? | I look at a 12 channel audio board and I see that there's only 2 inputs; one for channels 9/10 and another for 11/12. What is this and how is it utilized. Its also almost always a 6.5mm input so what does that mean? Thanks. | Technology | explainlikeimfive | {
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"The 9/10 and 11/12 inputs are TRS stereo 1/4\" inputs. TRS stands for tip-ring-sleeve and carries a stereo signal. A 6.5mm connector is a standard 1/4\" cable. Oldschool headphones used 1/4\" connectors, while new headphones use 1/8\" TRS connection. Does that answer your question?"
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m1uffm | How did they make ice before modern refrigerators? | before modern refrigerators and air conditioners people used ice but how was the ice made? | Technology | explainlikeimfive | {
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"They waited for it to get cold and then harvested ice from bodies of water. They would then store the ice in insulated boxes so it would last for a longer time.",
"The classic method was not to make ice, but to get naturally occurring ice and store it and ship to where and when its warm. The scenes at the beginning of Disney's \"Frozen\" where the men cut out ice from a lake and transport it away? That is actually fairly accurate on how it was done until not too long ago. It turns out that you can actually store and transport ice quite a bit without it melting. Store the ice underground in huge chunks and insolate them with layers of saw dust and similar for transport and you could make it stay ice for quite a while. People would harvest ice from lakes in places like the US east coast in the winter and then store it in cellars and ice houses until summer or transport it to where it was needed in places as far away as India.",
"Depends how far back you go. A long time ago they used to collect ice in the winter and store it in underground rooms. The rooms when filled with the ice would stay cold for months and not melt the ice. and so you could keep going in and grabbing some ice for whatever you wanted to use it for.",
"Fun fact: in Farsi, the word for refrigerator is \"yakhchal\", yakh meaning ice and chal meaning pit. Since around two and a half thousand years ago, they would dig a whole and build a dome on top of it with some kind of weird water proof, non-heat-conductive dirt mixture. The holes could contain millions of litres of ice, and the domes could be 10s of metres tall (to keep the hot outside air away from the stored goods/ice). These structures have actually survived to this day. I've been inside one of them. It was full of trash. But the point is there is pictures of them so you can actually see. I imagine this was an idea a lot of cultures would have come up with.",
"Not really that long ago, while my grandparents where alive, they had ice delivered to their house. They were farmers and kept the ice in chests in the cellars. It’s naturally colder underground so they ice lasted a good while if kept properly.",
"Either by storing ice when it was cold enough underground or somewhere insulted, or in some cases even shipping ice from cold parts of the world",
"As u/Larry2Thumbs had said, Ice was taken in huge chunks from different cold parts of the world. These huge chunks would last for months without completely melting. It didn't have to be taken from an arctic region however, it could be taken from a snowy place in the wintertime. They were stored in dedicated buildings called ice houses where it would last through the summer: [ URL_1 ]( URL_0 )"
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m23wf4 | How does a car radio know the name of the station, and the song playing ? | Technology | explainlikeimfive | {
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"There is a standard for this called the Radio Data System. It is a low bandwidth data signal that is sent on the audio but at three times the frequency of human hearing. So people can not hear it but a chip in the radio will be able to decode it. There is not much bandwidth but it is enough to transmit some simple text messages for the front display, the time of day, other radio transmitter nearby in case the signal fades, traffic information to the satnav, etc. A very similar system is also used on DAB radio to transmit the same information. However on DAB there is a bit more bandwidth and you can actually transmit small images as well so a DAB radio might show you some album art or the logo of the show as well."
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m26qkq | How can objects like laundry machine buttons ‘beep’ when they don’t have a speaker to emit the sound? | Technology | explainlikeimfive | {
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"A lot of consumer electronic devices do have a [piezo-electric speaker]( URL_0 ). It can't reproduce complex sound like human speech, but it can make beeps. The speaker may be hidden behind a plastic control panel and still be audible. There is a [microcontroller]( URL_1 ) (tiny cheap computer) that detects the button presses, and in addition to turning things on and off in response to the buttons (and perhaps activating lights or a small display), can send a [square wave]( URL_2 ) to the piezo-electric speaker to make a beep. The frequency of the wave can also sometimes be varied to make beeps of different notes.",
"They have a sound maker, it just happens to be inside the cabinet. Mostly this is to keep it dry and protect it from soap, lint, finger-poken, etc."
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m29s6c | Why did we ran out of IPv4 addresses but not out of phone numbers? | Technology | explainlikeimfive | {
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"Let’s do some maths, there are 4 numbers in an ipv4 address and each one can be 0-255, so 256^4 is about 4 billion A phone number has between 9 and 11 digits, downing on where you are that might change, so let’s pick 10. Each one can be 0-10 so 10^10 is 10 billion, already more than double, but there are country codes as well, so you basically have 10 billion numbers per country But even if we ran out of phone numbers, because of how the telephone system is made, you can just add a new digit in the front and it’ll still work, and this has been done in the past. However that doesn’t really work ipv4, as it’s only expecting those 4 bytes",
"We effectively *have* run out of phone numbers several times since they came out and we have changed the phone number system greatly to compensate. After there were too many phone lines for the operator to just connect you by knowing all the lines of the customers, they developed phone numbers. But they were strange things (to modern eyes) like CHelsea 4527. And if you wanted to call long distance, say from NYC to Chicago, you were first connected to the Chicago trunk, or main switchboard, who then connected you to RIver 2956 or whatever. Then later even that became too saturated (after WW2, it got so that many people could afford their own phone line as opposed to being on a party line, so numbers kind of exploded) so they introduced area codes, city prefixes, and 4-digit identifiers. Within the city, you didn’t have to use the area code but when dialing long distance, you did. In those days, long distance was not terribly far, FYI. I remember as a child it was long distance to call an address that was over the state line but since we lived right next to the state line (like I could walk to it without even becoming tired), that seemed ridiculous. Then once cell phones became popular, it became necessary to use the area code all the time, even from your land line. There are still some rural places, like my husband’s home town, that still don’t use the area code and locals there were perplexed with me for giving out my full phone number when they are used to only 7 digits. But eventually, they will have to use the full number. So, what’s next? I remember in the 90s, people saying that giving fax machines phone numbers would eat up all the available numbers and we’d be out of them but, of course, that never happened. I’m almost convinced that scammers who burn through phone numbers are the ones that are going to make us run out of our current 10-digit number system. You *can* reuse numbers somewhat but I believe there has to be a significant delay before they give the number back out. I suspect that within my lifetime, I’ll see at least one more major change with the phone number system. (This was about phone numbers in the U.S. I have no idea how phone numbers in the rest of the world were handed out and how they manage to increase the available field over time)",
"Well, for one there are only about 4.3 billion IPv4 addresses, and a lot of people have more than one device that needs an address. For phone numbers there a few things going on. 1. Phone numbers are a lot more complicated than that, their are international standards but in reality, each country can do their own thing. For example, the UK just...added other numbers to their phone numbers back in 1994. 2. There are more phone numbers, using the normal 11 digit codes you now get over 9 billion numbers (which again not everyone uses) 3. There are a lot fewer instances of a single person using a large number of addresses. Lots of people might have multiple devices but very few people have 6 different phone numbers. And if people do have multiple phone numbers oftentimes one of them is a work number. Which tends to use a single phone number and then an extension on top of that. For example, a company might have 900 employees each with their own extension used to call them. But they still only use a single phone number.",
"Phone numbers were handed out based on geographical area. And we know very accurately how many houses need phones in a given area for a long time. So we have been able to make sure that we use every possible phone number. IP addresses on the other hand was handed out based on network topology which followed organizational structures. But it is very hard to predict how many computers are going to be in each organization. So some organizations were given lots of addresses which they distributed among their departments and systems as they found best. But other organizations got very few addresses and had problems expanding into them. I have worked in organizations where even the guest wifi were set up with public addresses enough for huge conferences and I have worked at organizations that have had to cram hundreds of well paying customers into each address. The problem was made worse by the lack of foresight by the early adopters of IPv4. It was not supposed to be a worldwide network that everyone had access to. It was supposed to be a research network to test out various technology that could not be tested out on the old ARPANET in order to help design the up and coming OSI network that was supposed to be the next big thing. So the first organizations got ridiculously huge allocations so that they could easily segment it in a logical fashion."
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m2f3nd | How do we track Mars rovers if there is no global positioning system (GPS) on Mars? | Technology | explainlikeimfive | {
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"We compare the images from satelites surrounding Mars using things like HiRISE if you are interested here is a [link]( URL_0 )"
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m2jpoa | Why were IPV4 addresses so limited, when MAC addresses were made so much larger? | Technology | explainlikeimfive | {
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"text": [
"Because MAC addresses have 48 bits while IPv4 addresses have only 32 bits. This means that for every IPv4 address there are potentially 2^16 MAC addresses. Why? Because they were defined by two different organizations. The people who came up with IP thought that 32 bits were enough (and to be fair, at the time they were) and the people who came up with MAC addresses thought they needed 48 bits."
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m2n6i7 | What is the most simple device that can be considered to have "software"? Does it have to be digital? | Does a mechanical timer have software? What about a wooden marble adding machine? An analog watch? A musical box? A digital watch? A hand-held calculator? Where does software begin? | Technology | explainlikeimfive | {
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"Here is an analog [programmable device]( URL_0 ) that ha been around for a long time. The software was similar to the punchcards we used to use with mainframe computers. I wouldn't say that the device is \"simple,\" except in comparison to digital devices that are far more complex.",
"In general, software is a list of instructions for a processor to execute. So yes, it has to be a digital sistem and something that isn't \"hard-wired\" to do a certian thing (for example a simple logic gate). Software runs on systems that don't do anything by themselves and need to be additionally \"told\" what to do. This doesn't have to be in the form of code, it can be as simple as physically flipping a series of logic switches. Handheld calculators are generally hardwired for a specific task (except the fancier ones) so those don't have any software. But, \"software\" is a made up term and it doesn't really have any real physical counterpart to define it, so the definition can get a bit fuzzy. Edit: You could argue that by putting an equation into the calculator you're \"programming\" it or putting in software that it runs. That's where the definition really gets blurred.",
"You could say that the piano roll on the old player pianos or the cards on a jacquard loom are stored instructions, which would make them something like software. But neither is a simple device, and the software can't change the fundamental behavior of these devices like software in a modern computer can.",
"Software is a way to give \"instructions\" to a device to make it do what you want it to do. It is \"soft\" in the sense that it can be changed to make it do things in a different way. When I was a pre-teen, we had a \"digital\" clock, but it was digital only in that it moved black slats over the lights to change the numbers. (I was fascinated by this device, BTW.) In this case, it was the cams that pushed or pulled the slats back and forth that made the numbers. It was a mechanical device (some small electrically-powered timer) that would shift the numbers forward by moving a shaft each minute. I would consider this crude software; if the cams were shaped differently, you'd get different number, or arrangements that didn't make any sense. When most people talk about software, they mean instructions that run on a digital device that can store and retrieve data, can do math, and can make decisions based on various inputs (including existing data). But this is not the only type of programmability. For example, early automation for weaving cloth would use punched cards with holes that would tell it when to insert or relax a given thread, allowing patterns to be built up by weaving. This is certainly software, and someone had to encode (program) the patterns, but it was not really a digital device except for the push/relax of a given thread. So I would conclude that \"software\" is a fuzzy term that only relates to programmability that can be changed. These \"programs\" can be used in mechanical devices... in fact, all devices become mechanical at some point because the program has to reside in a physical device. The conversion from mechanical to digital is usually done with electricity (e.g., your mechanical keyboard converts the physical push into a signal), and it gets back to physical at some other point (the electrical signal lights up a display, or it actuates a robotic arm in a automobile factory). Whether there is digital processing in between is not always required."
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m2ou22 | Why does Rendering a Movie takes so long but a video game can render within milliseconds? | Technology | explainlikeimfive | {
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"Video game scenes are much, much less complicated than animated film scenes, in terms of detail, depth, resolution, lighting etc."
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m2r4sd | What is NFT Art Theft? | i'm reading a lot of complaints from other artists that art theft is now easier than ever thanks to crypto NFT tokens - as far as i understand, now art thieves can attach an NFT token to an artwork and claim it as their own? i don't really understand that, because just claiming it as you own doesn't automatically take away the copyright of the creator of the artwork? | Technology | explainlikeimfive | {
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"If I claim a NFT on a piece of art and then I sell that token, I am still profiting from the artists work. If the person I sold the token to then sells it to someone else, who can say that exchange wasn't legitimate? If the original artist tries to sell their original art, they might not be able to sell, or will have to sell for less if they do not control the token. The danger to the artists depends on how seriously people take NFTs. Artists are naturally very worried about NFTs because of the possibility of theft, so they will want to emphasize the flaws in the NFT model. They also probably should want to be very proactive about it, because 'blockchain' tends to make people believe something has legitimacy. It's worth noting that NFTs are not even the first instance of this behavior. It is a common complaint that there are bots that search for unmonetized music on youtube to claim, resulting in people getting copyright strikes on their original content plus adds on their videos that they don't get paid for."
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m2s9kw | How do shopping bots exactly work and what’s the best way to get rid of them? | Technology | explainlikeimfive | {
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"It's usually just a form of automation. They watch the store page for an item to be in stock, possibly with some limits like max price or something, and complete the order form with pre-configured information (like address, payment info, etc). Because it's an automated system, they can do this 24/7 without taking any breaks, which greatly increases the chances they're able to make a purchase before regular customers are. As for getting rid of them - you ultimately can't. You can add measures that make it more difficult to automate (like CAPTCHAs - those annoying images you sometimes have to decypher, or find all the images with a mountain in them or whatever)....but as with most software systems it's a constant cat and mouse game. Unless you involve real people being face-to-face to make a purchase, a vast majority of anti-bot measures can be defeated with more complex bots if the author is determined enough."
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m2sv9x | Why do they make power adapters so large that it’s difficult/impossible to plug something into the adjacent plug? | Technology | explainlikeimfive | {
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"Laziness and to save money. Adaptors are ubiquitous and very inexpensive and a well designed small adaptor need not cost a lot more. Most of these adaptors are sourced-in. Few companies bother to design them from the ground up. At most, they will send out an external drawing/industrial design and some reference material or finish required. There are good companies that spend the time to spec out adaptors that work well, fit their aesthetic and are small. They will spend a few dollars more to get it right. You have to spend more to get efficient, small form factor adaptors. Others just cheap out. You can get an off-the-shelf adaptor sourced with some custom labels/screen print and pay just a few dollars. (I've sourced OEM adaptors for less than 3 bucks in volume) Often times a smaller company just won't spend the resources and assign some junior buyer/sourcing person to bring in a couple of catalogs to pick from.",
"They don't design them to intentionally block adjacent plugs. They are that size because that's what's necessary to cheaply convert the incoming AC into the required DC for the device you're plugging in. They can do this either directly at the plug and keep the wire uniform all the way to the device, or they can make the types of cables often seen in laptops, with those large blocks along the cable. On smaller devices (that don't require as much power), those blocks are small enough you can put it right at the plug and only cause *some* issues such as blocking a nearby plug or two. The alternative is to move it down the cable so you have a smaller plug, but this adds more room for failure (you have two connection points - one for each side of the block, instead of just one coming out of the block). For some devices, like laptops, the block is virtually always too large to put on the plug, which is why they have the blocks halfway down the cable.",
"They make quite slim ones, but they cost more. Most manufacturers don't see sales dropping because people love their phone and hate its wall wart. As a result they go with the fat+cheap ones.",
"It’s like $5 to offset the cost to the consumer with a [mini extension cable]( URL_0 ). I’m sure there are better prices out there but I would agree that manufacturers should be required to have the power block down wire. I wonder what the exceptions would need to be.",
"Something else to consider is a lot of countries (especially countries that use 240v supplies) have bigger plug sockets that are spaced further apart, so large power adapters actually fit just fine. Companies always looking to save money aren't going to make a special, more expensive adapter with a cable for countries with small us-style outlets.",
"To have safety approvals (UL or similar) if you have another line-voltage cord that also has to be tested and approved separately and as a part of the assembly. Eliminate the extra cord by putting the male plug directly on the power supply box, solved, faster time to market. Also saves a couple feet of thicker copper wire which is also expensive. And one less detachable cord to lose somewhere / incorrectly package / etc. Otherwise if the supplier or construction of the line-voltage cord changes they have to re-apply and re-test the safety of the combined unit again."
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m2uf63 | How do holograms work? | Technology | explainlikeimfive | {
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"Light has wave-like properties. One of those properties is wavefront interference. That means two beams of light can combine to make either more light than the individual beams or less light. (Sound also does this, that's how noise-cancelling headphones work.) The most basic idea of a hologram is to arrange light so that when the intersection of two beams is viewed from different angles the resulting interference pattern looks like what you see when you look at a 3D object. This looks like a 3D \"image\" but it's not an object, you can wave your hand through it."
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"text_urls": [
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|
m30xbe | how does vga, dvi,hdmi, displayport,usb control each pixel of a monitor if the cable doesn't seem to have a wire for each and every pixel? | Technology | explainlikeimfive | {
"a_id": [
"gqma8yi",
"gqma9f3"
],
"text": [
"The cable is carrying a mostly serial signal...it's not sending data for every pixel at once, it's sending one or several pixels at a time (but so fast that the monitor can draw the whole display 60+ times per second). It's like how we can read a novel despite only looking at one page at a time...we read the pages in sequence and then we have the whole novel.",
"They sent every pixel information one after another. That is why if you film an very old tv you can see the screen building. [here is a slow mo video with a good explanation]( URL_0 )"
],
"score": [
13,
5
],
"text_urls": [
[],
[
"https://youtu.be/3BJU2drrtCM"
]
]
} | [
"url"
] | [
"url"
] |
|
m32sim | How does TensorFlow work? | Technology | explainlikeimfive | {
"a_id": [
"gqmlb3d"
],
"text": [
"Tensorflow allows python and JavaScript developers to use optimized machine learning algorithms without having to write them themselves. I’m currently building my own neural network for a college class so if you have a more specific question I can try to explain, but there’s too much to try and explain everything now."
],
"score": [
3
],
"text_urls": [
[]
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} | [
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|
m3588y | When art is being sold with an NFT, how is the image and ownership transferred? | Technology | explainlikeimfive | {
"a_id": [
"gqn1tdx"
],
"text": [
"The NFT blockchain only records a chain of transactions and, in theory, ownership. It does not transfer the actual work of art at all, it is more of a way to create an irreversible receipt independent even of governments. In fact not only does an NFT not transfer the original art as you thought, it doesn’t do many of the things people imagine it might. As I alluded to earlier it doesn’t actually transfer ownership of the art; creation of an NFT doesn’t establish that the creator actually owns the work represented, and the independent nature of the blockchain doesn’t apply to questions of ownership. Many people have created NFTs from works they do not fully own meaning that rather than trading ownership, they instead created a token to commit copyright infringement with each trade. And while an NFT could be used as evidence of a sale in a lawsuit, it isn’t obvious that it would be superior to a paper receipt. An NFT doesn’t even prevent the resale of an original work; someone might paint a picture, create an NFT from the scan which they sell to one person, then sell the original physical painting to a second person. In what sense does the NFT holder “own” the painting? It isn’t clear."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
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"url"
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|
m36132 | Why does TestOut tell me 4G internet is capable of speeds up to 1Gbps? | I'm doing online courses, and a TestOut LabSim video I just watched was going over mobile internet connections. They claim 4G can reach speeds of 1Gbps, though I find that incredibly hard to believe as that would make my cell phone internet speed 20 times faster than my home computer's. Is this some kind of laboratory conditions theoretical max or are they just wrong? | Technology | explainlikeimfive | {
"a_id": [
"gqnab4j"
],
"text": [
"From the LTE Advanced Wikipedia page \"Three technologies from the LTE-Advanced tool-kit – carrier aggregation, 4x4 MIMO and 256QAM modulation in the downlink – if used together and with sufficient aggregated bandwidth, can deliver maximum peak downlink speeds approaching, or even exceeding, 1 Gbit/s. Such networks are often described as ‘Gigabit LTE networks’ mirroring a term that is also used in the fixed broadband industry\" To my more layperson understanding, that is something along the lines of combining multiple LTE connections into one effectively faster one."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
m3737g | In software, what exactly is a framework? | Technology | explainlikeimfive | {
"a_id": [
"gqnry4v",
"gqna6u6",
"gqneoef",
"gqnd1h7"
],
"text": [
"A lot of people here are merely defining what a library is, which is just a chunk of code that someone else wrote that provides useful utilities. A framework goes further and creates an entire way of doing things. Often, it feels like a whole new language built on top of the base language. It imposes some sort of \"opinion\" about how things should be done. Consider trying to make a complex website in HTML/CSS/JS. It's entirely possible to do so with no libraries/frameworks, but it's painful. When the user clicks something and you want some new content to appear, you have to write the code that programmatically generates the new elements, then go find where those elements should be inserted in the HTML, and call a bunch of clunky `appendChild` functions. jQuery is a *library* that makes a lot of this easier. It provides a bunch of useful functions that make it much easier to create new elements and stick them in the HTML. But you're still fundamentally doing things the same way. React is a *framework* that not only provides useful functions, it defines a whole new way of writing interactive websites. It has very strong opinions about the \"right\" way to write a web app. Instead of thinking about how user actions should cause visual changes, you think about the app having a \"state\" at any time. User actions modify state. And then you write code that defines what the app should display in terms of the current state. You never write the HTML-modifying code yourself, some magic under the covers does all of that for you.",
"Say you needed a wheel. You could, a) build it yourself, or b) go get one already built. Frameworks are kinda like that. Its code that makes it easier to build apps without reinventing the wheel every-time.",
"Comparing software engineering to building a house, you can build anything from scratch, buy different parts from a retailer to build and put it together to build your house. So let's say you're building from scratch, you can customize everything. But you have to craft every window from those woods you cut, or maybe your language would have precut woods which you can immediately use to build. Framework is like using a ready made stuffs from certain retailer. You go to home depot to buy certain countertop, windows, doors, etc to use. There are some products that look and work like other retailers, but there are some stuff that you can only get from certain retailers. So if you need certain size windows, you may have to buy from certain retailers or you have to build one yourself. So you could technically buy 10 windows and make 1 custom one just for a specific use. Which is similar to using framework, but building specific interface for a specific use if you need to. Even when you buy from retailers, you still need to nail them together, etc. This is like using your own code to use the framework to build the house. Edit: I stand corrected. What I'm explaining is indeed a library, not framework.",
"Think of it as a tool kit. Rather than building your own hammer/ screwdriver, you buy/borrow the tools from someone else and then make your own project with it."
],
"score": [
23,
10,
6,
5
],
"text_urls": [
[],
[],
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[]
]
} | [
"url"
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"url"
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|
m3aeix | Why is media not formatted to 16:9? | Mainstream (all?) TVs these days are 16:9 displays. Why is media not? Movies aren't, lots of YouTube content isn't. If 16:9 isn't the ideal ratio for content, why are our TVs? Do the black bars at the top and bottom "add immersion" of some kind? School me. | Technology | explainlikeimfive | {
"a_id": [
"gqnskhv"
],
"text": [
"Like most things in life, 16:9 is a compromise. Movies started off as 4:3 back in the beginning. As a result, TVs ended up being 4:3 to be able to show movies and shows shot on 35mm film. As technology advanced directors started to use wider formats to be able to give movies a more epic scope and they kept getting wider all the way out to Panavision's 2.35:1 ratio. When you overlap 4:3 and 2.35:1 rectangles, a 16:9 rectangle covers both the height of the 4:3 frame and the width of the 2.35:1 frame. This means the tallest film and the widest film both fit in the box and have as little black bar as possible. When the standards orgs were drawing up the plans for HDTV they decided to go with this aspect ratio so that both old 4:3 content and old wide content would look acceptable and new 16:9 content would fill the screen. Since the conversion to HDTV was only back in the 2000s, we have all this content that wasn't recorded in a 16:9 format and we get black bars."
],
"score": [
12
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
m3aym7 | Why did people in Texas get really high electricity bills? | Technology | explainlikeimfive | {
"a_id": [
"gqnw7c2",
"gqnuqig"
],
"text": [
"Imagine that you wanted to buy a hamburger, and go to the local hamburger restaurant. Now this hamburger restaurant is special, it takes all of the hamburgers that are cooked everwhere in the city and sells them to anyone who wants a hamburger. We will call this the Hamburger exchange. Now the exchange has two interesting features. First, if more people want to eat hamburgers than there are cooked hamburgers, the price of a hamburger goes up (and vice versa). The second is that you don't get to know the price of the hamburger until AFTER you buy it. On a normal day, you can go to the Hamburger restaurant and buy a hamburger for $10. Some days it $11, other days it is $9. Now you normally only buy one Hamburger a day, and the price moves very slowly, so maybe on Monday it was $11, $12 on Tuesday, $13 on Wednesday, and you decide not to eat a burger on Thursday because you dont want to pay any more than $13. Then, one day, there is a beef shortage and there are almost no hamburgers being cooked (You dont know this right away), however, on the SAME DAY you also find out that the ONLY restaurant open is the Hamburger Exchange. There is no other food available. So you buy three hamburgers because you cant eat anywhere else. At the end of the day, like always, you find out the price you have to pay for these hamburgers, and to your utter surprise, your bill is $300! This was because everyone else was also trying to buy hamburgera at the same time as there were almost none being cooked. This basically explains the TX Energy system. Prices for electricity are based on supply (number of cooked hamburgers) and demand (number of people wanting to buy hamburgers). However, you dont actually know your current price of electricity until you get your next monthly bill. This created a situation in which a whole bunch of people wanted electricity (because of the cold weather), while no one was supplying it (because of shortages and shutdowns). This cause the price of electricity to skyrocket. The issue is that there is no real time feedback on the price of electricity. You dont know whether your fridge is going to cost $10 to run, or $10,000 to run. Normally, this isnt a big deal as prices are very stable, and dont really move around much from month to month. During the bad weather this created a really bad situation where people should have reduced their electricity usage to save on their bills, but didnt actually know they needed too.",
"Some people had signed up for variable rate plans, which adjust the rate based upon the current wholesale raid (which varied based upon supply and demand). These plans can be beneficial if you can shift your energy usage away from peak consumption periods. When the freezing cold tempatures hit, the reduced supply and virtually infinite demand caused the wholesale electricity rate to soar, causing those customers on variable rate plans to see their rates jump to the maximum $9/kWh. However, because of the situation, not taking advantage of what opportunities you have to avoid freezing to death would be unrealistic, and many of those users ran their heaters when they had electricity despite the potential for surged rates."
],
"score": [
21,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
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"url"
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|
m3c85o | What is camera obscura? How and When it happens? | Technology | explainlikeimfive | {
"a_id": [
"gqoaeuz",
"gqo13ef"
],
"text": [
"Imagine you have a large TV screen facing a wall 2m away. The light from the TV is hitting the wall, but you can see a picture on the wall. It's just all fuzzy. This is because the light from the TV shines out in all directions. The top of the wall is getting hit by light from the whole TV. Now suppose you put some kind of screen up in the middle, 1m from each side. You poke a tiny hole in the centre, which lets a little light through. Now, the top of the wall can see through the hole to the bottom of the TV. Similarly, the bottom of the wall can see the top of the TV. This means light from the TV shines through the pinhole onto the wall, and projects an image of the TV which is upsidedown and back to front. The smaller the pinhole, the dimmer the image is because less light can get through. But *also* the sharper the image is, because the light is more directional. This is how a camera obscura works. But instead of a TV, it can just be the outside world. If you put a film inside, you have a pinhole camera that you can take pictures with.",
"Basically a enclosed box with a tiny hole, light travels through the hole and the world outside projected on the wall parallel to the hole. It was used to make painting back in the day."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
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|
m3co8n | How does a phone know when another phone is calling them? How do they not get interrupted by other phone signals? | Sorry if the question doesn’t make any sense, I’ll try my best to restate it if it’s unclear. | Technology | explainlikeimfive | {
"a_id": [
"gqosd8d"
],
"text": [
"The cell phone tower will issue each phone with a time slot and frequency when it is allowed to transmitt and when to receive. When the phone is in standby the time slots will be very small and far between. But when the phone starts using data or a phone call is made the time slots become longer and more frequent to allow for higher bandwidth. The cell tower will make sure that no two phones are given the same time slot on the same frequency if they are close enough to interfere with each other. This often requires cooperation with other nearby cell towers."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
m3on4o | Why do we need to free up some space for software updates? | It’s just frustrating sometimes especially my watch requires 3gb of space for it to update. Now I have to delete apps and data. Doesn’t it feel like a rip off? Shouldn’t be the update space separate? | Technology | explainlikeimfive | {
"a_id": [
"gqpzmu3",
"gqpz66o"
],
"text": [
"You need space in the kitchen to bring all the groceries in, before you're able to unpack them and put them away. You need space on your device to get the updates, before it's able to unpack them and install them.",
"You need to have space to download the files, oftentimes those files are compressed and need to be decompressed (expanded) so they can be put in the right spot. It would be a terrible day if the update just tried to replace files needing update as it downloaded them, because if *anything* happened - internet disconnected, your device restarts, etc. - then it could royally screw up how the device works. So it *has* to download everything and make sure it's all there before it starts replacing/updating files."
],
"score": [
19,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
m3v58y | How Does LIGHT Carry Data? | Technology | explainlikeimfive | {
"a_id": [
"gqr27v2"
],
"text": [
"The light used in fiber optics is of very specific frequencies. Like your local radio station. It is sent just like an electrical signal in that it is digital, meaning there are high points and low points. The high points could represent a one and the low points a zero. Many, many of these specific frequencies are packed very closely together, hence the large amount of data. They work almost exactly like wires but are very low loss, meaning most of the signal gets through. This is very simplified."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
m3viq4 | Why does oil and grease make phones have that weird glitchy look when on a screen? It doesn’t happen with water | Technology | explainlikeimfive | {
"a_id": [
"gqs0lci"
],
"text": [
"bends the light, oil has the ability for a smear to split the whole light spectrum into colour parts With light hitting it you see one effect, with phone screen light hitting it you see another from the other side, the two together make it look trippy and glitchy"
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
m3wdvp | why do game console developer kits look ugly? | Technology | explainlikeimfive | {
"a_id": [
"gqrcnbq",
"gqrbosi"
],
"text": [
"Because designing nice looking cases costs money. Developers don’t care about the aesthetics of the computer/console they’re developing for; they care about the internal hardware and the software development tools. Studios don’t want to pay more for dev kits just so they look cool in developers’ offices. And console makers don’t want to waste time/money on designs for something only developers will ever see.",
"Hardware specs still in flux Not for retail sale so no need for them to look pretty Sometimes additional components like more than one NIC, so loses some of the possible sleek factor"
],
"score": [
10,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
m3wp66 | why do games have so many dll files? | Technology | explainlikeimfive | {
"a_id": [
"gqrc6m6",
"gqs6zua"
],
"text": [
"They're called library files because they contain resources for programs to work. They are accessible by multiple programs to share the data, but only when needed so it saves on memory. Each library would have a specific functionality though, so that's why there are a lot of them, but since they're only used when absolutely required they don't waste a lot of system resources.",
"Games do not \"have\" .dll files, they \"are\" the .dll files. DLL files are libraries of purpose-related programs. A game is a very complicated assembly of those programs, therefore it requires many libraries to serve different purposes. You will have a separate dll for network, graphics, sound, input, disk interface, etc. Everything that happens in the game is coded in one of those."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
m3z78o | How does the internet work? | Pretty sure I’m still going on Ted Stevens’ “series of tubes” metaphor. | Technology | explainlikeimfive | {
"a_id": [
"gqrxkun",
"gqrt97n"
],
"text": [
"A good analogy to understand the internet is by comparing it to mailing letters. You send a letter to a place requesting content. Maybe you send a letter to Sears asking for a catalog of all they have on sale. Your letter is delivered by your internet service provider (ISP) instead of the postal service. It gets sent to Sear's IP address instead of their street address. Instead of someone opening your letter, reading your request, and responding by sending a catalog back to you, Sear's servers do all of that. They send your requested information to your IP address instead of your street address, in the form of a web page your browser knows how to read rather than a letter.",
"A bunch of big companies interconnect all their computers. Then they let you connect to them and tell your computer how to get to fred's computer over on Amsterdam Street so you can buy that special brownie"
],
"score": [
8,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
m3zz0o | What does it mean for ETH to be more like "gas" than an actual currency? | Technology | explainlikeimfive | {
"a_id": [
"gqs4aal"
],
"text": [
"In short, it allows it to do, rather than to have. In analogy: gasoline can get you to the other side of the continent, money can't get you anywhere, unless you spend it to let someone else get you to the other side of the continent. The Ethereum network allows addresses to contain code, scripts and values, to be executed in transactions. These scripts are called contracts. This means that a script execution is open and transparent, and the execution cannot be tempered with. But you'd need gas to execute it. So again, instead of paying a third party, like a bank or accounting agency, to do important, official business, you would be able to see and trust the actions of the network. Let's take the purchase of a house as an example. I do not have the funds to directly purchase a house, but the contract on address XYZ is written by a mortgage supplier, and allows you to register for a mortgage. An address making a transaction to this contract is registered in the contract. Now, why is this different to a website offing a mortgage? We have to trust whatever code we can't see on the website, but any transaction and it's content, including the publishing of the contract, is public. Whatever the contract is doing, you can see it. It's quite a complex matter, but I hope I did answer the question at least a little bit. I'm happy to answer any further questions"
],
"score": [
15
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
m41l18 | Why do smaller rechargeable batteries (smartphones, power banks) use mAh to measure capacity, while larger batteries (laptops, EVs) use kWh? | How come some use Watt-Hours and some use Ampere-Hours? | Technology | explainlikeimfive | {
"a_id": [
"gqsbatm"
],
"text": [
"When you are comparing batteries of equal voltage, using Ah or Wh are basically the same because you can just multiply by voltage. For example standard car batteries are 12V and their capacity is quoted in Ah. Why not Wh, which would work equally well? The things that a car battery powers (starter motor for example) pull a known current so it makes sense to quote capacity in current x time. This applies to phone batteries that all work at the same voltage. In contrast electric cars have batteries of a range of voltages. Roughly speaking higher voltage is more efficient and more compact but requires more expensive components. Hence designers pick different values depending on their needs. Given you care about the total energy stored in the battery, and you don’t necessarily know the voltage, it makes sense to quote the capacity in Wh."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
m445uh | why do batteries charge quicker when they’re empty. | I’ve noticed that my phone will charge really quickly up to 50%ish and then the speed it charges to 100% is much slower. I’ve found this true for other devices too, why do batteries charge quicker when they’re empty and then the speed slows down to get it to 100%? | Technology | explainlikeimfive | {
"a_id": [
"gqsjlhc",
"gqsh6zn"
],
"text": [
"Think of pouring water into a mug. When it's empty, you can pour quickly. But unless you want spilling boiling water all over, you have to slow down when it's getting full. Overcharging batteries, especially the lithium kind is bad. It damages the battery and can result in the battery catching on fire if you really overdo it. That's why these days we have charge controllers that take care of doing the charging right, and protection circuits that will disconnect the battery if something goes wrong.",
"This is because of how modern lithium battery charges. The battery starts with a \"constant current charge\". Where the charger gives the battery the amount of electrical current the battery is rated for. And the battery charges at it's best speed. However, as the battery fills, the voltage inside the battery goes up. And to avoid damage to the battery the charger now has to switch to \"Constant voltage charging\". Here, the charger feeds the battery only with a certain amount of voltage or \"pressure\" and the battery simply takes as much electrical current as it can handle. And it charges signifficantly slower therefore."
],
"score": [
8,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
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