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lewd3n | what exactly is a troll? | Technology | explainlikeimfive | {
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"The etymology of \"troll\" in the internet sense doesn't come from troll meaning a mythical creature. It instead comes from the action \"trolling\" which is fishing by luring with a baited line dragged by a boat. Internet trolls post provocative and inflammatory content in order to lure other people into replying to them.",
"The original usage, during the late 90s and early 2000s, was someone who would pretend to hold dumb or inflammatory beliefs that they didn't really have in order to get a reaction out of people. So for example, a troll might go onto a forum for women and go \"no see i just really believe that all women are secretly lizards in costume prove me wrong\" just to make people mad. Modern usage has shifted a bit, I think largely because media outlets didn't understand the old usage. The new usage is broader, and refers to anyone who is posting in bad faith. For example, let's say I'm a politician and I want to call attention to a particular problem that is embarrassing to my opponent. I could wait for people to talk about it organically, or I could hire ten people to go upvote every post on my local subreddit about it, make some more with side accounts, \"discuss\" among themselves to make it look like everyone's mad about it, etc. Those people would be trolls in the new (but not in the old) sense.",
"The origin of the term didn't have anything to do with the mythical creature troll, but [trolling for fish]( URL_0 ). The connotation is that the troller is just fishing for reactions rather than putting out their sincerely held beliefs. The intent is what makes an activity trolling or not. Someone posting misogynistic statements to /TwoXChromosomes because they genuinely believe women are inferior isn't trolling, but someone who posts the same misogynistic statements because they enjoy the negative reactions it produces is trolling. The term has evolved a bit over time to be a catch all term for vexatious internet actors. For instance, a \"troll farm\" most often doesn't refer to a group looking to get reactions for reactions sake, but a coordinated effort to post bad faith statements with a political or financial end in mind."
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lex1ba | If Internet cables can carry a lot of data per second, why won't these cables replace HDMI/VGA/DVI standards? | Technology | explainlikeimfive | {
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"\"If trains can carry a lot of people very fast, why don't they replace walking, biking, cars, and planes?\" Different strengths and drawbacks is the short answer. Being single-purpose (only image data) has advantages over a genera purpose bus, and point-to-point connections also don't need to have a forwarding or routing protocol to go with them. Data can be preprocessed in a way that is easier for the end device to decode, so the receiver can be simpler and cheaper. Physical connectors and cable can be made without caring as much about long-range performance if you can assume that the devices will always be close to each other. And on and on. \"Data\" is always the same in an abstract sense, but in a physical sense there's a lot of possible paths you can take to create a data transport system.",
"The short explanation is that HDMI is faster than \"internet cable\" There is not a single cable called \"internet cable\", there are cables you use for computer networks the common in households are ethernet in a copper cable like CAT-6 and for long-distance, it is an optical fiber. The problem is that the data rate in ethernet is high but not as high as the other you mention. The max data rate in the now common HDMI 2.1 standard is 42.6 Gigabit/s compared to the common ethernet today of 1Gigabit/s. You will see some 10Gigabit/s ethernet on expensive motherboards. The 10Gigabit/s ethernet standard is from 2002 so when DVI was introduced in 1999 the max speed was 1Gigabit/s. DVI had a speed of 3.96Gigabit/s in the single line that HDMI adopted and 7.92 Gbit/s is the dual-link variant. There is 40 Gigabit/s electrical ethernet too over the wire but it requires quite complex and advanced electronics. There is a faster optical standard but the cost is a lot higher. HDMI is the same as DVI with a different connection and sound added. VGA is an analog standard. For the same speed at the distance that we used HDMI, they are cheaper and better designed for video than to use ethernet. Ethernet has an advantage in max length but the electronics you need for the speed cost more than the HDMI."
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lez36f | Why do Hollywood filmmakers need huge cameras when simple DSLRs and even my phone can record 8k video now? | Technology | explainlikeimfive | {
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"This is actually a good question, because in principle you could get near-cinema quality out of a MUCH smaller camera than what currently gets used for big budget feature films. Most of what cinema cameras are made of is a thick heavy metal body, cooling fans and manual button controls, surrounded by loads of optical accessories, cables, batteries, handles etc. Basically all stuff that doesn't really improve image quality but more so improves usability on the film set. Only the lenses really affect the image's look in a way that can't really be miniaturized. The Hollywood camera companies actually don't get to take advantage of the economies of scale that are provided by mass-manufacturing in the way that smartphone makers do, because they address a tiny customer base to begin with. For that reason alone, small cameras and smartphones have improved exponentially over the past decade in terms of video quality, while cinema cameras hardly provide any improvements in image quality over what was available 5-10 years ago. Ultimately, color quality and dynamic range are what sets those professional cameras apart from consumer cameras. The gap is quickly narrowing though.",
"There is more to image quality than pixel count. There is pixel size, signal-to-noise ratio, color bit depth, depth-of-field, frame rate, bit rate, video codec, audio recording interface, time sync, global shutter vs. rolling shutter and other things I’m forgetting. It’s like the difference between owning a Cessna and a 747."
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lf0xpw | If OLED Displays have near instant response times, then why aren't all OLEDs high refresh? | Technology | explainlikeimfive | {
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"a lack of processing power. OEMs tend to focus on post-processing of image quality and various audio tricks rather than the fastest refresh rate- doing so generally makes for a better TV experience for most people ...personally, I want to watch the news in 240Hz smoothness so I can respond quickly when [anchor A] is actually going 'back to you, [anchor B]'"
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lf1nfk | How do overlays in NFL look so real? Like paint? How are they so accurate? | Players can walk over them and stuff and nothing happens, almost like they are real paint in the grass. | Technology | explainlikeimfive | {
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"Lots and lots of money thrown at it. Essentially it's the same concept as a green screen, where a computer will recognize certain colors and only overlay where it is supposed to. But to make it work using the field which isn't a nice bright uniform green they have to recalibrate the colors a number of times before the game and during the game. Selecting players uniform colors as stuff not to overlay, selecting the field colors which change depending on lighting, etc. It does help that they also have position encoders in all the cameras so they can calculate what parts of the field are where based on where the camera is, where its pointing, and how far it's zoomed in.",
"They're essentially green-screen— almost literally. The software only applies the overlay to things on camera that don't move: grass yes, players, refs, and ball no."
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lf4g0a | in older times how did we get metal ores? | Like i know you just melt it down and voila metal but like how did they know what rocks? What was the process surely you can't just melt rocks and get iron, right? How did they know this rock has iron and that one has copper? I understand gold and gold panning did they just pan for copper or whatever metal they wanted that seems to inefficient? | Technology | explainlikeimfive | {
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"Metal ores are minerals that typically have a specific color. You can learn to recognize various ores with some practice. For instance, iron ore often has that distinct red rust color. They learned what rocks were like this through trial and error. Then, you smelt it. I can't do the smelting process justice, but the gist is that you roast the fuck out of it.",
"Watch how to make everything it's an amazing yt and he's doing a series where he starts from what's the earliest known of technology and \"advances\" each episode and explains it very well whilst demonstrating. From memory with things like iron it's litteraly sprinkled all over earth in the dirt",
"It's difficult to fathom just how long humans have existed. There has been more than enough time for humans to find some funny looking rocks, heat those rocks up whilst trying to do something else (perhaps a pottery kiln was made from the rocks), notice that the thing they melt into is pretty interesting, and then go out looking for more of that type of rock. Eventually, over quite a lot of trial and error, these civilisations figure out what they need to be looking for that indicates metal ore. When they find a good deposit of it, they set up a settlement there so it's easy to access. Metal ores tend to be found next to other instances of the same ore due to the way geology works, so once you've found one coppery rock you aren't going to have that much difficulty finding more of it. Also, yes, getting metal ore was a very inefficient process. Then once you've got your copper, you've got to find some tin to mix it with, and tin is pretty rare. The first bronze-age civilisations in the Mediterranean (The Egyptians, Greeks and Hittites) collapsed into a dark age when migrations disrupted the fragile trade routes they used for tin. It took hundreds of years to recover. Making bronze was difficult and expensive. The key benefit of the discovery of iron was just that it was a hell of a lot easier to produce. Finally you could equip a decent-sized army with weapons and kill even more people."
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lferc1 | Machine Learning | I saw "The Social Dilemma" on Netflix and got very curious (and terrified) when they started to talk about machine learning and artificial intelligence but couldn't really understand it and how it works.. | Technology | explainlikeimfive | {
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"Machine learning is a field dealing with statistical models that automatically adjust themselves and improve given more data. It's really not any more than that. The actual math is somewhat (though not extremely) complicated and would be meaningless without a background in more basic statistics, though.",
"Summary of machine learning. Me: Hey, what's 2+2. Computer: 13. Me: Not it's 4. Computer: Yes it's 4. Repeat many many times. To be a bit more specific what machine learning does is to make estimates on many many different dimensions. As for what a dimension is. Imagine you want a computer to tell the difference between a duck and a bear. One dimension could be, does it have a break, or does it not have a beak. A second dimension could be does it have fur or feathers. A third does it have two legs or four. Though with machine learning the dimensions are very low level, and there are many more or them. Things like, are there two black pixels directly to the left of two white pixels, at position (2,2). Or is the third letter in a word \"o\". Because the training is automatic it lets you replace human time developing complex algorithms with computer time. You do however need a lot of well labeled data. With things like facebook facial recognition they can source their data from people just tagging their friends. Other projects may rely on just paying people to manually tag a lot of data.",
"What computer scientists call Artificial Intelligence and what movies call Artificial Intelligence is not the same thing. AI researchers call a computer that can think in ways analogous to a human an AGI, for Artificial General Intelligence. The widespread consensus is that we are nowhere close to achieving that, nobody serious is even trying, and it may not even be possible. The AI stuff they are working on are what used to be called expert systems - they're designed to do one task, and only that task. You generate a big database of example data that's been interpreted by humans, and you design a basic algorithm to try and interpret that data. Then, you generate a bunch of random variations on that algorithm, test them, and the discard all but the best couple. Then you generate a new generation of algorithms based on the winner, etc. Eventually, you end up with an algorithm which is much better at performing the task than what you could have written... and you have no idea how or why it works. You've probably heard a lot of people complain about the way Youtube's algorithm works, particularly in cases where, say, people get demonetized for sexual content for saying \"I'm a gay man\", or the requirement that they upload videos every week to get recommended, etc. Youtube has no idea how to get an algorithm to account for that. Because you need something testable to grade your algorithm on, and they chose \"length of time people spend watching videos\". And they don't even know how their algorithm works to tweak it manually. Anyway, these kind of systems are only good at one thing. Remember google deep dream? Remember how it makes everything look like an amorphous pile of dog faces? That's because it was trained to recognize animals, so when you show it a photo, it doesn't learn to recognize more stuff, it just sees the parts of the photo that kind of resemble animals.",
"With traditional algorithm you have someone telling the computer exactly what to do in order to answer a potential question. So for example if you want to find out the gender of someone based on their browser history you might have someone write a number of checks in order to find out their gender. You might hardcode lists of names and their genders, different websites that you know are male oriented or female oriented, etc. The computer can then follow these instructions and give you an answer. But with machine learning you are not telling the computer directly how to find the answer to the problem. Instead you give it a system for finding its own solution and then a set of data that gives examples of correct answers. The systems may be statistical analysis, neural networks, tensor flows, etc. So after applying the techniques on the example data the result would be an algorithm designed by the computer instead of by a human. The advantage to doing this is firstly that you can then reuse the same code to find solutions to other problems. So you can for example use the exact same system to instead figure out if people will vote Republican or Democrat instead of finding their genders. And the computer is often able to find more complex patterns then a human can as it will be able to look at far more parameters then humans. So the algorithms made by machine learning is more accurate and cheaper to make then those made by humans. These machine learning algorithms is used a lot to handle massive amount of personal data. The examples I gave with the categorization of people is a fairly common example. There are algorithms that claims to be accurate enough to determine when a women is going to be pregnant even before they are trying. But in addition to categorizing it into groups we might be familiar with it can also categorize people on things like which advertisement would be most efficient. You can make an algorithm which is able to say that people like you were more likely to buy a product after seeing advert roll A rather then advert roll B. And that gives advertisers a quite powerful tool that makes people do what they want. That is just a simple example as well. An advertiser might even base their entire advertisement campaign on what their models predict that people will respond to. So you end up with actors having to say lines that are written by a computer based on how people respond to different words."
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lffx1s | Why aren’t there universal parameters for online passwords? | How is it 2021 and password parameters are completely site-dependent? Character limits, no special characters/special characters required/only certain special characters, etc. I feel like the various rules makes it more likely people will use bad habits like writing passwords down, or making less complex passwords more likely? Edit: Upon further discussion in the replies, with many good points being made, I realized my real question should have been: why do some sites set password parameter limitations? I should be able to input a 25-character complex passphrase with letters, numbers, special characters if i want whether it’s for my Netflix account or Bank account. What I don’t understand is my bank being like, “Nah, you can only use 12 characters, and you can’t use @“. That’s my frustration, and was more my questions because I figured there was a technical reason behind it likely. | Technology | explainlikeimfive | {
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"Because that would require a singular, universal authority to come up with such a thing and no such thing exists. And it is unlikely to ever exist because there isn't universal agreement on what the parameters for passwords should be. In fact, just about the only thing that is agreed upon with regard to passwords is that they suck and should be replaced with something else. And even if there was a \"universal parameter\", people wouldn't be forced to learn it or use it.",
"On the other hand, if there \\*was\\* some sort of universal password system on all sites, hackers would know exactly what setup to target with any brute force hacking approach. Not to mention that people who are going to write down their passwords would probably otherwise have picked something really weak anyway, so it doesn't make much difference.",
"> Edit: Upon further discussion in the replies, with many good points being made, I realized my real question should have been: why do some sites set password parameter limitations? I should be able to input a 25-character complex passphrase with letters, numbers, special characters if i want whether it’s for my Netflix account or Bank account. What I don’t understand is my bank being like, “Nah, you can only use 12 characters, and you can’t use @“. That’s my frustration, and was more my questions because I figured there was a technical reason behind it likely. Sometimes there are technical reasons. For instance it's going into some sort of SQL query, and they want to make sure it won't screw it up somehow. I can expand on this if you like. Sometimes it's customer service. You don't want to deal with people who set up their password on a Russian system and now can't figure out how to type that on a Mac with a Spanish keyboard. The same goes for unusual characters. On some layouts it's very easy to get an € or a £. On others you'd have a hard time. So forbidding anything strange reduces the likelihood of somebody running into such issues. Sometimes it's some ancient system sitting in the middle that hasn't been updated in the last 3 decades, and so you have to play by its rules. And often times it's just some random standard or \"best practice\" that's been inherited from somewhere else and nobody bothered to think about much. The dev just had it burned in their brain that passwords top out at 8 characters on some earlier project, so 8 characters is what gets written into new code.",
"If there was a standard, it would be obsolete within a short period of time or be so complex no one would be able to remember their passwords. Passwords alone will never be that secure. This is why two factor authentication (2FA) is becoming quite popular.",
"How would this be implemented? There is no central service for managing passwords so every implementation is up to the service that is using the password. What if one database doesn't support a specific character but other databases do, do you just not support that database and *force* a service to switch databases or die (because they can't have passwords if they don't use this password requirement service), or do you let them determine their own requirements? There are many forms of guidance on what password requirements *should* be, but you can't enforce it if there is no central entity to do so. Besides, if a US company starts up and somehow gets authorization to *require* US-based websites to use them for password guidance, that doesn't mean other countries have to respect it."
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lfisx8 | When companies talk about "self healing" plastics like, in the case of, screen protectors for phones, what are they talking about and how does that work? | Technology | explainlikeimfive | {
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"A self-healing material is one that has some way to repair itself without any sort of human intervention. That can take a variety of shapes, from including a repairing agent mixed into the material that takes some form of action in response to damage, to having the material re-form completely by itself. In the case of plastics: pretty much all plastics are some sort of polymer. That means they're made up of many repeated small units (monomers), each connected to the next in some way. Self-healing plastics have the ability to re-form certain bonds under normal operating circumstances (as opposed to \"normal\" plastics where you'd create and shape the material under high temperatures, pressures etc in a specific factory environment). It's complex material science and I can't give exact specifics, but that's the gist of it."
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lfplww | I work in a building that struggles to get 5G or LTE service. Will a mobile hotspot work/help? How does it work? Do I have to connect it to the same service provider I have or can it be a free-standing provider? | Technology | explainlikeimfive | {
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"It connects to your mobile phones internet so it's with whoever you have your phone contract with. It uses your phone's data, it can't be free-standing. If you don't get 5G on your phone, a hotspot won't help you."
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lfr47i | What decides how “big” or how many gigabytes a video game is going to be to download? | i never understood this sole question: what is being downloaded when you download a game, and what makes each game however many gigabytes? Is it the 3d modeling of maps? The coding and game mechanics? | Technology | explainlikeimfive | {
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"Audio is huge. The whole script is often in several languages. Textures can be huge as well. Prerendered video. I think these 3 things are a large part.",
"While u/Vixxay is right in that most things grew, they did so at extremely different rates. The actual size of compiled code for example is still below 200 MB for almost every game there is. For most games more like 50MB. There are specific assest types responsible for the growth of game sizes, and that's first and foremost textures and prerendered videos. They have doubled in resolution multiple times in the last thirty years. And every doubling in resolution means four times as much disk space. Textures in AAA games now take up at least 16 to 32 times the space than thirty years ago. To a lesser degree the rest grew too, albeit a lot less drastically. Models have more polygons. Audio is maybe double the size than a decade ago. But the *absolute* brunt of it is textures."
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lfs30x | How polygraphs exactly work and what makes them not admissible in court? | Technology | explainlikeimfive | {
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"1. They don't work. 2. #1 is why they aren't admissible in court. A polygraph measures certain physical responses like pulse, skin conductivity, blood pressure, and respiration. There is absolutely no solid scientific evidence to support the idea that any of these measures can reliably indicate lying, and in controlled studies polygraphs are no more accurate than random guessing.",
"Polygraphs read vital signs like blood pressure, pulse and perspiration while you're being interviewed. They're inadmissible because there's no science that says you're necessarily lying if any of these vital signs are abnormal during an interview. They're mostly used by police on dumber criminals to get them to confess to something the cops already think they did."
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lfsgeg | How does a computer know how long "1 second" is? | How does a computer know what length of time is one second long?? | Technology | explainlikeimfive | {
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"There's a tiny crystal made of quartz that shakes if you pump electricity into it. They found that it always shakes at more or less the same rate for the kind of circumstances most most humans can survive in. So they measure how often it shakes.",
"There's a little rock in there that jiggles at a consistent speed. They just count the jiggles. So like every 100,000 jiggles is one second (not actually this number).",
"Processors have an oscillator built into them that cycles with a known speed. The processor \"knows\" that this oscillator flips states X times a second, and it counts how many flips it's done."
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lfv3pd | How does computer compression and decompression work? | Technology | explainlikeimfive | {
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"\"The car is the best car in the world\" X=the Y=car \"X y is x best y in x world\" Now imagine that in binary."
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lfxkcv | When a processor says it can perform 1 million operations per second, where is it getting so many instructions from and how is it able to handle them so quick? | Technology | explainlikeimfive | {
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"\"Instructions\" at the processor level, are basic operations on basic bits of data stored in memory. The most basic would be literally something like `Take the number stored $HERE and add $X to it.` $HERE represents an address in memory, and $X is maybe something the user typed. At the end of the day, computers just move numbers around, or compare them and make decisions. Nearly every complex thing your computer does comes down to a LOT of very, very simple instructions that basically look like `If $X is less than $Y then set $Z to \"true\"` (and on many CPUs, even that \"instruction\" would be broken up into lots of even simpler instructions.) It takes literally millions of these VERY basic instructions to do even the most simple (from a human perspective) stuff. Clicking a button on a website has millions and millions of instructions just to create the image of the button your screen, and millions more to animate the push of that button. It seems impossible at times, but when broken down to the absolute basics, everything a computer does could be done using nothing but LOTS (millions) of the simplest calculators... and a lot of scratch paper (that would be the RAM or memory) as well as other paper for long term storage (hard drives.) As for how it does them so fast, there ARE literally millions of \"calculators\" on a CPU, just shrunk down really, really, really small. Many of these literally do the job only of feeding instructions to the others. And when every one of these calculators operates (executes one instruction) at the \"clock speed\" of the CPU... Well, when you hear about a \"3ghz CPU\" that means 3 BILLION times per second every calculator on the chip could (potentially) being doing something. In reality, it usually takes a few clock cycles to execute most instructions, but it adds up quickly anyway.",
"In RAM, a processor can only read instructions from memory (although it can seem confusing, memory is not the same as storage, it’s different form hard disk or SSD), which can be RAM, or internal cache, both of which are incredibly fast, especially cache This is also why games need ~~losing~~ *loading*, the computer has to copy everything into RAM so it’s able to run the program",
"> where is it getting so many instructions from * It gets them from system memory. > how is it able to handle them so quick? * Computer processors are made by stacking a huge number (billions) of circuits together called transistors. * These transistors are tiny electrical gates. * When electricity walks up to the side of the gate, the gate lets other electricity through. * When the electricity walks away, the gate closes and the other electricity stops. * That very simple concept is the basis for every single complex things computers do. * And because we've figured out how to make the transistors very very small and use only the tiniest amount of electricity to do it's thing, we can operate then extremely fast."
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lfyipj | How is our info based on our internet activity sold? | I know that our info is being sold in some way but not sure what kind and how. | Technology | explainlikeimfive | {
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"Your browsing habits (types of websites, topics you are interested...) are what are sold, along with personal info such as your name, address, phone number, etc. Basically if someone sees you going into a sporting goods store a lot, they’ll assume you like sports/sporting goods and start sending you advertisements for those types of things in the hopes that you’ll buy *their* products instead. Same thing for websites you visit."
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lfyor1 | Ethereum and it's proof of stake. | I don't really understand what proof of stake is... I want to get into mining ETH and I don't know how this relates and no one seems to explain in simple terms. | Technology | explainlikeimfive | {
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"There are two common ways of validating/accepting new blocks. One is proof of work, which is what f.i Bitcoin uses, and involves in a sentence \"Spending a lot of electricity finding a number that can be used to prove the block is valid\". This is fine and all, but many consider it wasteful and favoring those with large computing resources. Proof of stake is simply summed up as so: > When the network needs to validate a block it will pick a random validator on the network and ask it to validate it. Nodes with more coins or older coins associated with them are more likely to be picked than people with fewer, because they have a higher stake in the network. Essentially if I have 10 ETH \"locked\" in my validator node, and you have 50ETH locked in, you are five times likelier to be asked to validate it than I am. Now, there are some limits and safeguards to prevent the extremely rich from validating every time, but that's the jist of it. How can we trust the validators? Because they have stake in the network and need it to work. If they sign off on a faulty or manipulated block people will stop trusting the chain, and the coins they have will drop in value. You, as the validator, have stake in the system and want it to succeed so that you can sell your coins later for a profit (or use them as a currency, your choice). If playing dirty means you'll lose more than you gain then you have no incentive to not play fair. There are no \"miners\" in ETH, only validators; and Validators need to essentially put up collateral to have any real shot of being picked as a validator for a block. If you play fair you get rewarded and can cash out your rewards and the collateral you put as stake."
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lg2my2 | Car thermometers, how do the get the correct temperature without interference from engine heat/wind drag etc? | Technology | explainlikeimfive | {
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"Ok, i assume you mean the thermometers that tell you the outside temperature, and NOT those used to monitor interior/engine/... temps. Engine - just dont place it near the engine. The hood itself is full of conducting metals, but any other place should be fine. Wind - wind actually helps getting the correct reading. What wind does (for dry objects) is accelerate heat transfer, so the thermometer will adapt faster to the air temperature. A thermometer in 10° air without wind will show the same temperature as one in 10° air with wind - the one with wind will adjust to the correct temperature faster. What WILL falsify the reading is moisture, especially when its windy and hot (due to evaporative cooling) - this could be dealt with by placing the sensor in a place thats protected from water splashes and rain.",
"The wind is your friend if you like to measure temperature. So you put the sensor where air from the surrounding will blow over it before the car can heat it up, the simplest way would be in front of the engine. The wind chill is relevant you try to keep something warmer or colder than the air like a human but for a sensor that should be at the same temperature as the air wind simply make it faster to respond to a change in air temperature. You as a human-like to stay at a constant temperature. So you put on clothes to reduce the rate heat can leave your body. If the rate is the same as you can produce heat you will keep a constant temperature. If you replace air around you and from your clothes that you have heated up with new cold air you will cool down faster. The feal like temperature is help for you so you can determine the number of clothes you need. The value is calculated from a model of a human in a specific set of clothes and a bare face walking into the wind, it is not a general value for how the extra cooling effect of wind. That is why wind chill is important for you. The air is not cooler because of the wind it can just cool you down to its temperature faster. If the goal is to cool down an object to the same temperature as the air the wind will cool down faster. The wind will increase the speed at the temperature drop but not what temperature the object will be finally reached. The air can only cool down an object to its own temperature. The win will result in faster cooling but the final temperature is the same. & #x200B; The result is a temperature sensor it an object you like to have at the same temperature as what you measure. So the wind from the car moving will result in a quicker change in temperature. What you like to keep the sensor away from is direct sunlight because it can heat it up."
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lg3xx2 | Is captcha really effective against bots? If yes, how is it effective? | Technology | explainlikeimfive | {
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"They are somewhat effective. It is fairly difficult for machines to understand the contents of an image as anything other than \"an image file\". We take for granted all the things out eyes and brain process for us automatically. Teaching a machine these things is an incredibly costly and time consuming endeavour. In fact, you help do it sometimes without realizing it. Google is a bug fan of those, \"click every picture that contains a car\" captchas... these actually help with machine learning. These days there is more AI and machine learning and they will gradually become less and less useful as those become more commonplace. For the time being however individuals have limited access to those kinds of resources making captchas a still somewhat effective tool at doing what they do. Their only real function is to slow down account creation and make it difficult for a machine to generate thousands of fake accounts."
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lg41tg | How do green screens work? | Technology | explainlikeimfive | {
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"Green is a colour that isn't very common in humans. At best some people have green eyes, but even then, not typically the same kind of green as the green screen. As such, we can aggressively remove the background automatically without having to manually define the edges of the foreground. In old days there would be a chemical process to remove the green from one layer of film and then it could be played back with a different background. In modern times, this is done completely via computer.",
"Strictly speaking it's not necessary. Even videoconference software now can use image processing algorithms to automatically determine which part of a video is the person vs the background. The results aren't perfect, but for cheap software working in real time, it's pretty good. A green screen just makes the software's job easier by creating a clearer contrast between the person and the background.",
"It doesn't *have* to be a green screen, it just has to be a color that isn't being used in the rest of the set and costuming design, which is often light green. In modern times, they use a computer to filter the color of the background out for the rest to be superimposed onto another video. In films like Hulk, where there might be a lot of green on the actors, they might switch to a blue screen or pink screen for their masking, or just make sure that the green they're using for the characters is substantially different from the green screen. Green is most commonly used because it is distinctly not similar to all shades of human flesh. The process began in the earliest methods of filmmaking, with black matte draping being used to superimpose actors into footage via double exposure."
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lgc0dy | Why do some computer programs need to be "installed" whereas others will run from an .exe file? | Basically what the title says, sometimes I can run programs as a standalone .exe file, but sometimes the program needs to be installed instead. What is the difference between the two? | Technology | explainlikeimfive | {
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"Some programs are like an individual hot wheels car that you get when you behave on a shopping trip. You can play with it just all on its own. These programs are usually smaller, and don't need to rely on much else or make any special changes to your computer. Others are like hot wheels cars that come one of those boxed sets you get for your birthday. They come with tracks that have to be put together; you have to ask your dad for batteries, or you have to grab a chair and clamp the track to it; you have to put some ice water in the little container so the cars can change colors. These programs try to do a lot more, or work together with other bits of code, but they require more setup as a result.",
"A program that can be run straight from an .exe file needs to be fully self-contained...the computer is going to load the first instruction from the .exe file to memory, run it, and away you go. This doesn't mean it needs to be a single file, but if it's multiple files the .exe file needs to be hard coded with where the other files are or how to ask the OS where other files are. However, if the program needs other resources that may or may not be installed on the system, or needs to tell the OS various things to work (what kinds of files it opens), or needs information from the OS (what kinds of printers are out there, what other software is on this machine, etc.) then it needs to do more \"housekeeping\" to get that information, install anything that's missing, setup preferences, etc. That's what \"installing\" does.",
"some ...actually most programs rely on having supporting libraries, this can be handled in one of 2 ways: - \"bake\" these libraries into the executable, while this makes your program self-contained and wont require any installation, it increase the size of the final .exe file and forces the operating system to load the whole thing on startup which might be a problem if memory is limited.This also creates an issue if you want to actively support the software, as any update to the libraries you want to implement requires a full recompilation not to mention not all middleware providers actually allow you to do this as their software could be proprietary and could land you in legal trouble especially if your software is not free. - include references in your code that point for these libraries, in a \"relative\" directory and make calls to these libraries dynamic. this has the benefit of keeping your own code contained on itself, with its only outside connection being these calls, however this requires that when you distribute your program you must include its dependencies in the form of dynamic link library files aka .Dll files. this method also facilitates updates as an update is only required if the actual library call is changed. Because most Users do not want to have to manage possibly multiple versions of the same .dll, programmers develop installers that manage this for you while also changing any required options so that the program can do what's intended.",
"Windows developer of 15 years here. Most of the answers submitted here (so far) are based on specific experiences/use cases - or are just plain guesses and not right. Dependencies for example, does not mean you HAVE to use an installer. My best ELI5 is software applications are like home electronics. Some applications are microwaves (just plug it in and it will work) - these are EXE's, no complex setup required. However some applications are like home alarm systems, they require holes to be drilled, hardwiring to power and maybe connecting to the phone line. In the real world you would use an engineer to fit it, as it is very complicated and you (the user) could make a mistake. This is exactly what installers do in software, they take care of all of this work for you and ensure it's completed properly and can be reversed (uninstalled) in the future if required. Edit: A word",
"Imagine that apps are people you hire to come over to your house and do something for you. Some of them do simple tasks and are very organized. They bring everything in a backpack, take out just what they need, and put it back when they are done. That’s like an app that is a single .exe file; it has everything it needs in one place. Some have big jobs to do, and need lots of tools and equipment to do the job. Think of a painter who brings a truck full of ladders, tarps, and different colors of paint. The painter might move all this into your garage while they are working. That’s like an app that needs to install lots of files on your computer to function correctly. Of course, some people might be able to keep things in their backpack if they were organized, but when they show up they just spread out all their stuff over your living room. Some apps do that too, even though with a litte care they could have been made as just a single .exe file.",
"There's 2 main reasons to have an installer. The first is if there are dependencies, that is the program assumes something else is installed (in modern times, assuming Windows, this will likely be something like the .NET framework). The installer can check if this is already installed, and prompt you to install it if it isn't already there. The second that an installer isn't needed, but there's other typically expected things, like adding a start menu shortcut. There are also things like some programs can add options to your right-click menu on certain file types, and this is usually done during installation. It can also be considered more user friendly depending on the audience. Sometimes these programs will offer two versions, a stand alone version that you can unzip and run, and one with an installer. Another potential benefit of an installer is that it can include an uninstall that will remove the shortcuts it created, as well things like asking you if you want to remove the data created. It can also be useful when upgrading versions to have an installer update any existing files that are needed. If the official Windows installer framework was used to create the installer, it can also be aware of Windows system restore so when you restore to a point in time, that program can either be installed or uninstalled as appropriate. Many programs don't actually need an installer, but not having one can make your program look unprofessional if it's meant for a consumer audience.",
"Not much, usually applications have supporting external libraries and configuration files. These need be placed in relation to the executable. An installer usually handles this for the user, on Windows, it may also add registry entries.",
"Normally programs are a collection of EXE files (windows world), not just one. A simple one may be simply one EXE, but more complex ones will contain others that can be called upon depending on what the user is doing. So, what does the program have to do. If it can rely, 100%, on the operating system software (like a simple \"Ping\" program or something) then you only need the exe and maybe a simple config file. Say you have a more complicated program that is capable of scanning something, so as part of the 'installation' you have to register some DLLs (which are just 'libraries', think of them as tiny little programs that operate as shortcuts for developers, instead of coding everything from scratch you might load a DLL that someone else developed, without DLLs development would take FOREVER) and a device 'driver', or special program just to run a specific input or output device. Some installations will even go further and install a web server or something so you and other computers can access the program remotely. So, in that case, in addition to installing whatever special software you have designed, you also have to install httpD (or IIS, whatever). Think of the installation as 'prep work' for the program, the prep work is different for each program. If you are installing a SQL server, the prep work is extensive. If you are installing Notepad++ the prep work is trivial."
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lgcf6v | How do those Dyson fans with no blades work? | Technology | explainlikeimfive | {
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"Through lies and deception. There are fan blades hidden in the base of the fan, take the fan apart and you can see a turbine in there."
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lgdtlq | if the oldest movable printing press exists in Korea, so does the oldest books from the printing press... why are the Germans credited with ‘inventing’ it? | Technology | explainlikeimfive | {
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"There were limited uses of it in China and Korea, but the Germans are the ones who really made mass production viable, kicking off the age of the mass-printed book. One big help is that they only needed the letters of the alphabet, so they could just make molds for only that many letters to make a huge amount of type for printing.",
"While the movable printing press were developed in East Asia long before Gutenberg it never really created the same sort of printing revolution as it did in Europe. There were several reasons for this. There were far too many letters in the alphabets to make the typesetting process faster then the carving process. There were also issues with finding the correct type of ink to produce good quality text when printed. And also the noble classes did not want this technology to fall into the hands of revolutionaries as they might mass produce works they disagreed with. In addition printing presses were used in banking to mark valuable papers with unique serial numbers which also made the technology secret. So the printing press you are mentioning, which is arguably the oldest, belonged to the king of Korea and were kept secret from his subjects. In fact owning a printing press in Korea at that time was prohibited by law. So there was only this one machine in the entire country. Meanwhile in China they had abandoned movable printing presses entirely because they were too slow and unreliable. So the East Asian inventions were not as significant culturally as the German invention. This is why we credit Gutenberg with his invention instead of any of the East Asian inventors.",
"Because it didn't gain world wide attention until the 1970s and was forgotten about until 2011. Historians, even when they are unbiased (which isn't a given) aren't omniscient. Point being, the people who wrote the history books crediting Gutenberg weren't aware of the Korean invention. Secondly, two people can independently invent the same thing. You don't have to be the *first* person to do it to be an inventor of it.",
"The printing press in Europe is an independent invention from the Asian printing presses. Contrary to what other people are saying here, printing _did_ cause quite a revolution of bookmaking and literacy in China. See this askhistorians thread for example URL_0 But Gutenberg's press is the ancestor of modern printing presses, the ones we use today which is why it gets all the press. It's also the press that European historians and schoolbook writers of the past tended to know the most about (since among other things you didn't have to wade through sources in Chinese or Korean to learn about it)"
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lgen6a | How does a transistor in a computer get told what to do? (Turn on or off) | So from my understanding, a computer is composed of millions or even billions of microscopic transistors. These transistors are configured in elaborate ways to make different gates to interact with each other. My question is, fundamentally a transistor is basically a switch. But instead of a human turning the switch on or off with their hands, you have another wire doing it for you. Now, in a computer what is controlling these transistor gates to turn on or off? Is it other transistors? | Technology | explainlikeimfive | {
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"Yes. Other transistors. It's a huge chain of them. This chain loops in many places as well. However, there are some external sources. First, peripherals. Keyboards, memory drives, cameras, and whatever else. Other networked computers, even. Alternatively, the clock. The clock is an oscillator, turning on and off regularly. This tells the computer when to begin the next operation, as well as keeping time for time-related activities. All computers have a clock. The clock is typically a quartz oscillator; a piece of quartz which vibrates like a tuning fork, driven by electricity."
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lgf8ib | Polarization and screens | I noticed that when wearing my polarized sunglasses I can't see my phone screen, but I turned my phone sideways and can now see clearly. Does anyone have a good explanation for this? | Technology | explainlikeimfive | {
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"Yes. Light is a wave. It is polarized perpendicular to the direction it moves. If it is moving up or down, then it is polarized in some horizontal direction. Part of how phone screens work involves polarizing all of the light. If your sunglasses and the screen polarize in the same direction, then you can see it. If they 'disagree' then your sunglasses will absorb the light instead.",
"Polarized glasses basically have very tiny straight lines on them. When light goes through the lenses, these lines stop any light that isn't already running in the same direction as those lines from getting through. This is polarization. Your screen has a polarized filter on it, so there light coming out is also polarized, running in the same direction as the tiny lines on it. If the lines on the phone run in the same direction as the lines on your glasses, you can see the images. If the lines are rotated 90 degrees, you see nothing at all."
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lghlsh | What limits digital transmission speed in a usb port for example? | Technology | explainlikeimfive | {
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"Any connection (not just USB) is limited by: * the number of wires used for data (the more wires, the more data can be sent at the same time, over separate wires). * the length of the cable (the devices that are connected via a cable must \"synchronize\" their electronics in order to transmit and receive properly, and the longer the cable is, the lower the maximum frequency of bytes that can be transmitted). These are physical limitations. In addition, you may have \"design\" limitations. For example, USB is a standard, meaning that everyone has agreed to follow the rules as designed by the [companies that originally designed it]( URL_0 ), in 1996 or 2011 or whatever. So because some years have passed, there may be artificial limits built into the USB standard that everyone has to follow because it's a standard. Phones and computers may be a lot faster now, but it's a standard so they can't transmit faster than the spec. for USB.",
"Oh man, let's go on a trip. The first thing that limits transmission rates is physical switching speed. Newer transistors can switch faster so therefore more speed. Back in the days of parallel ports we got more data across with more wires. But then something interesting happened. When you start switching too fast signals from wires next to each other cross over, kindof like how transformers pass energy from one coil to another. This of course screws up signals. So then we went back to serial data and just switching faster. Thus USB. At this point though you start running into problems with signal reflections and the actual quality of wire you are using. If the impedance (resistance to AC current) of a wire isn't constant over the wire you get reflections of the signal. It works kindof like how sound echoes. This can be worked around to a point by regulating the quality of connectors and wires. USB 1 you could probably run over telephone wire and be fine. USB 2 needs twisted pair (reduces noise interference) and shielding to get it's speeds) With USB 3 you get even more speed from multiple pairs of wires. Though unlike in the old parallel ports days each pair is individually twisted and shielded to prevent interference. In addition the hardware does a bit of signal analysis on the cable to compensate for differences in the cable. That's just a brief partial overview of USB. In a more general sense what limits transmission over copper. Frequency: Faster is better. Duh. Usually limited by current transistor technology. Impedance mismatches. When the cable changes impedance it screws with signal quality. This can be overcome with signal processing and quality control on the cable to a degree. Voltage used. Higher voltages can overcome resistance and capacitive losses in longer cables, or you can use multiple voltage levels to send more than just one bit at a time. It's harder to get voltage to swing over a larger range though so in general if you are using a higher transmit voltage you are loosing out on max frequency. External noise interference. Generally overcome with differential signalling and twisted pair wire and shielding. Wrapping signal wires in foil blocks external noise from stray radio waves, and more twists in a wire reduces external noise interference. More twists in a wire also increases capacitance and therefore needs more voltage to maintain the same max frequency so that's a trade-off as well. All these tradeoffs are why there's different standards for different types of data. Ethernet, HDMI, USB, PCIe, etc. They're all balancing range, speed, and cost to implement."
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lgjvqc | How do LED lights work and why do they last so long? | Technology | explainlikeimfive | {
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"LEDs work by using voltage to bring electrons up to a higher energy level in their atoms. When they drop back down, they have to lose energy and they do so by emitting light. They last a long time because they don't have the same failure mechanisms as incandescent or fluorescent lights. Incandescent bulbs get the filament very very hot so that it will glow brightly. That high heat leads to various failure mechanisms such as evaporation, and the transitions from hot to cold add more. Fluorescent bulbs create a mini-lightning bolt when started up and then rely on a plasma to operate. It's kind of amazing that either type of bulb lasts long at all, given the extreme conditions."
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lgk9qb | Aside from piracy, what are the other major implications of a games source code being leaked? | This situation with CD Projekt Red is crazy right now, but I don't understand why the games source code being leaked is such a big deal since it's a singleplayer offline DRM-free game. People could pirate it day 1, why does this make any difference? They can't find any exploits that would allow them to hack into peoples computers remotely, since it's an offline game. What are the actual negative implications of a source code leak? | Technology | explainlikeimfive | {
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"One perspective is that if a game's source code were to be leaked, it could be used to achieve a company's result of it's hard work that it paid for. Example aside from Cyberpunk 2077: Let's say a company produces a racing game with the most realistic car physics on the market. They've invested millions of dollars into creating this grade A experience for racing games. If that source code were to be leaked, it could be used by other studios without them needing to spend a dime. Even if it's not just copied and pasted, the ideology behind it could be applied, again, with someone else footing the bill. Hope this helps.",
"It mostly means the homebrew and mod community will be able to do a lot more things a lot more easily, and the publisher won't be able to do much to stop them."
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lgkywg | - Considering the technological advancements in the last 50+ years, how comes the relative appearance of astronaut suits have remained the same since then? | Technology | explainlikeimfive | {
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"Appearance has nothing to do with technology (check out the high fashion from the era of Louis the XIV's time), but there haven't really been any fundamental changes in suit technology. The requirements of the suit haven't changed and the tech stack hasn't really changed so the suits look basically the same. Materials have gotten better, so the newer suits are a little less bulky and a little cleaner looking, and the helmets got better with better transparencies, and the backpacks got smaller, but functionally there's very little difference between the newest suits and the Apollo suits. Humans didn't change size or needs. It's like asking why pants have looked basically the same for several centuries. The SpaceX suits were very deliberately designed to look more high tech but, ironically, the visual cues are all non-technical...they're pure fashion. A lot of the true tech changes, like seals or computing or materials, aren't changes you can see easily. A carbon fiber racing skull looks exactly like a wooden racing rowboat from 100 years ago until you get up really close and inspect it. Edit: typo"
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lgn9i9 | What exactly is a game's source code and how can stealing it be bad? | Some hours ago I came across a news about how CD PROJEKT RED was hacked and, among other things, had the source codes for three of their games stolen. What does it mean for the company to have something like this leaked? | Technology | explainlikeimfive | {
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"Source code is kind of like coca-cola's \"secret formula.\" Anyone can buy a coke, drink it, try to determine what it tastes like, but without some very high tech and expensive equipment, you probably can't figure out exactly how it's made. If you were to break into coca-cola headquarters or wherever they store the recipe and steal it, you could start making your own coca-cola impostor soda, which would of course be bad for the original brand. So, as for the code side of that, like the other reply said, some awful people could plagiarize that code and use it to make their own games, therefore profiting off the honest work of other people. If the source code that was stolen is for games that aren't released yet, then that information can be used to leak what the games will be about, and how they run. Side note: There are some programs and games that are \"open source,\" meaning the source code is freely available, usually on places like [github]( URL_0 ). Anyone is free to use, modify, and usually redistribute these programs as they see fit, and it allows people to examine the code so they can see that it's safe to use/find out if it contains malware. The downside is that the original author of the code can't directly profit from selling it.",
"There's source code then there's compiled code. The source code is what the programmers write out. Other programmers familiar with the language it is written in can puzzle out what it does, and even use sections of it for themselves. The compiled code has been converted from the programming language humans understand into the 1s and 0s that computers work with. It is generally nigh impossible to puzzle out what each bit of code does. Your computer knows what to do with 1s and 0s, but someone trying to take those and use the code for their own game would have a very frustrating time to the point it's not even worth it. Someone with the source code for a game could pirate the game, more easily create cheats for the game, or copy the game's code to use in their own game. They probably could be sued if it is proven in court that they made use of someone else's code, but if the game that rips off that code is compiled, then it would be difficult to prove.",
"The source code of a piece of software is what the developers typed up to make the project. There are tons of examples of source code out on the internet to look at to see what it consists of, but it's just thousands and thousands and thousands of lines of written code that is proprietary material - meaning it's like a book someone wrote and it's their property unless they release it for public use. The reasons this can be bad include things like maybe the project isn't finished and they don't want someone to possibly steal their unique ideas or even use the code to enhance or release their own product before the original company does or can, or maybe the source code contains unique and innovative ways to approach challenging problems in the industry and they don't want competitors to gain that knowledge and have an upper hand like they do. The very simplest reason is that it's hard work put into a huge project that will allow them to make profit and stay in business, and they don't want their work to be taken from them."
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lgntn9 | could the M1 Bazookas in WW2 penetrate any German tanks? How do the warheads work? | Technology | explainlikeimfive | {
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"It used what’s called a “shaped charge” warhead. There’s an explosive shaped like a funnel, wide end forward, in the warhead. The funnel is lined with metal. The fuze at the front sets off the explosive on contact. The explosive squeezed the metal lining into a very thin VERY high velocity jet of liquid metal, like squeezing a watermelon seed between your fingers. The jet is so fast and high pressure that it can blow right through solid armor.",
"Yes, but no. u/tdscanuck already explained how a bazooka explosive works. The bazooka could penetrate up to about 100mm of steel armor. That sounds like quite a lot, but the top tier German tanks, Panthers and Tigers, had that much frontal armor. Some of the tank destroyers had even more armour. As a result, although the bazooka was effective, it had real trouble getting through the frontal armour of the bigger German tanks and was only good against them from the sides and rear. The US did start developing a more powerful Bazooka towards the end of the year, in part based on the German much stronger Panzerfaust and Panzershrecks, but those didn't reach the front lines until after the war. Still, bazookas and other shaped charge weapons actually did make infantry much more dangerous to tanks."
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lgpooa | Why is it better to buy a course from an educational site when you can find it on the internet on some shady sites for free? | Technology | explainlikeimfive | {
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"If you're asking: Why should I pay for something, when I could just *steal* it, and get it for free. Then I'm sure you know the answer. If you're asking: Why should I pay for something, when there are free alternatives? I'd say it depends on the context. The advantage of a paid product, can be that it's maintained and updated - also a financial investment in something, can help with motivation:) Whereas with an old free course from 2015, you could easily run into problems like dead links and so on. But there definitely are a lot of free good sources for a lot of subjects.",
"Just two reasons I can think of. 1) It supports the creator of that content when you buy their course. 2) Those shady sites are usually illegal."
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lgtnml | Old phones use antennas to get their signal in and out. What is the replacement for the antenna in modern cellphones and how does that work? | Technology | explainlikeimfive | {
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"It took some time for cell phone designers to find out how properly place an antenna inside the cell phone itself. The antenna is effected by the metal chassis, wires, battery, the users hand, etc. So it is much easier and better to have the antenna stick out of the phone. And designers still get the antennas wrong, as Apple demonstrated a few years ago. But with modern materials, miniturization of electronics and antenna simulations we have become pretty good at designing antennas that work from inside the phone itself. In addition to this we now have far better cell coverage so we are not relying so much on good antennas and the frequencies of the cell phone networks have gone up which means the antennas have gotten much smaller.",
"I’m pretty certain they still have antennae, they’re just built onto the inside of the phone chassis instead of protruding from it.",
"Antenna bands. Phones still use antennas they're just hidden. Fun fact: most phones don't have radio antennas, but you can replicate an antenna system by plugging in a set of wired earbuds"
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lgtyii | Considering Chess provides perfect information of its board state and has zero randomness, how come the game isn't 'solved' yet? | It seems that there are still chess bots/AI being developed and being improved until now. Seeing as how all possible actions can be calculated and saved in a database ahead of time, why isn't the game solved by just 1 Chess Bot that has all the best moves to win/draw the game everytime? | Technology | explainlikeimfive | {
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"There are far too many possible actions that we couldn't get close to calculating and storing them all. The number of possible board positions is somewhere in the same region as the number of atoms in the Milky Way galaxy.",
"\"Solved\" is a very tricky word. There is a fairly massive database of endgame positions which are solved in the sense of the word you are describing. For each one of these positions, every possible line has been simulated, and every modern chess engine is equipped to play perfectly to the inevitable loss, win, or draw. But these are all positions with relatively few pieces on the board. When a computer engine evaluates a position with many pieces on the board, it is actually horribly inefficient to perform such a brute-force calculation. There is simply not enough time in the universe for a machine - no matter how fast - to run a brute-force calculation from the starting position. So engines evaluate opening, middlegame, and many endgame positions from a set of qualitative criteria, as well as through advanced AI algorithms where they learn how to play the game.",
"Because there are practically infinite amount of states. White has 20 possible moves at the start of the game. Black has 20 possible responses. So that's already 400 states. But then it becomes even bigger and more complex. There are such a massive number of possible states that it becomes unfeasible to compute them all. So yes, chess is solvable. You could compute all possible states and find an optimal strategy, but it isn't solved because we are technologically limited.",
"Eli5 answer: Our best computers beat humans at chess every time. It has been many years since a human has beaten a top chess computer. Right now, our technology limits us and we cannot completely solve the game yet. There isn't enough time to calculate and store all the information. But perhaps when computers get faster and have more memory in the future, we could solve it. Chess computers use advanced \"pruning\" techniques. Solving the game would require searching through every possible board state and finding the optimal strategy for it. We cut or \"prune\" a lot of those board states out, however, because they seem like they shouldn't happen when the chess computers are playing well. So the computer only looks at board states it thinks are likely to come up in the next several moves, rather than all of them. This way, it can make a move much faster. Remember, official chess is played with a clock!",
"The game tree (every possible move) is far too deep and cycles back on itself (i.e. there's nothing stopping players ending up in an infinite loop of just about any size). But the sheer size of that tree is the reason. That a computer can win now is quite amazing, there's a reason that IBM Deep Blue was such an achievement. If you think that's incredible, the game tree for Go is several hundreds of orders greater, so Go, despite looking a much simpler game, is almost impossible to build a game tree for in the foreseeable future. Which is why Google's AlphaGo is DAMN incredible. These machines are some of the most powerful on Earth with stupendous amounts of storage. And neither are enough to store and analyse the entire game tree for chess or Go (chess is feasible... it may actually have been done already and I'm not aware, but Go will likely never be done with any number of conventional computers). We're talking numbers like 10 to the power of 360 - ridiculously more game positions than even atoms that exist in the universe (10 to the power of 80), and things like that."
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lgu1n3 | Why are videogame cutscenes, intros and menu scenes rendered in real time instead of using a pre-recorded video? | Technology | explainlikeimfive | {
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"You might have different armour on when the cutscene happens, or if it’s a different time of day in game? It should look fairly consistent with the game as you’re playing it when you trigger the cutscene.",
"It saves space (videos are big) and allows characters to be customized - with the gear you have on type of thing.",
"Historically going back to the days before optical media became the dominant form of distributing games, it was a limitation of just how little storage capacity flash NAND cartridges or floppy disks had. It cost only a fraction of the storage space to script everything to happen in-engine using all the game assets you had anyway, than it was to package a video of that happening. It was only once optical media like CD's started appearing with huge gains to storage capacity (if at a performance cost, load times are now a thing) that you started to see video assets in games, most notably with the entire FMV (Full Motion Video) genre. Which did kick off an era of pre-rendered cutscenes. You can now include high quality rendered cutscenes that in no way could the hardware of the time actually run in real-time. Final Fantasy as a series did this a lot early on, though it had a lot of janky in-engine cutscenes as well because CD/DVD can only hold so much. That held until recently, when hardware with the previous and current generation really started to make high quality scenes runnable in real time *and* now storage space is starting to matter again since digital downloads are becoming a dominant means of distribution.",
"There is one main reason for using pre-rendered cutscenes, which is that they can look better than in-engine ones, due to having more time and resources to render more detailed models, advanced effects, and more complex environments. Conversely there are several benefits to using in-engine scenes. 1) File size - video files are much larger than a set of scripted animations. Most of the scenery and assets in the cutscene will be the same as used in game, so don't take up any more data (there will be exceptions where scenes take place in areas that aren't playable, for example, but even then they will use less data than video). 2) Adapatability - scenes can be dynamically adjusted depending on the game state. For example the gear your character is wearing or has equipped, which NPCs or party members are present, the time of day, or even the actual location of the scene. Doing this in pre-rendered scenes would require rendering multiple versions of the scene to account for differences. 3) Seamless transitions - the game can switch smoothly from gameplay to cutscene and vice-versa, which can be more immersive. 4) They can look better. Strange one this, as it is exactly the same benefit I claimed for pre-rendered scenes, but in many cases those don't look as good as they could. They may have been rendered at lower resolution or framerates to save time/costs, or have heavy compression to save space. Especially in the late 2000s/early 2010s, it wasn't unusual for it to be obvious that you'd entered a cutscene as the resolution dropped from 1080p to 720p, frame rate from 60 to 30 or 24, and suddenly you were seeing a lot of compression artefacts.",
"It can only be pre-recorded if no dynamic parts are in it. So if a character wears a custom outfits, or any parts of the cutscene can be influenced in any way it must be created in real time",
"- Cost and complexity. Pre-rendered scenes typically have a completely separate production process and sometimes are done by an outside studio. It's a lot simpler and cheaper to just have an in-house dev script the models and scenes you already have. - Space. Before games on CD's started to go mainstream in the mid-1990's, games simply didn't have enough space to store movies (and PC's didn't have the processing power to display them). - Dynamicness. In-engine cutscenes can show different versions, e.g. if your character doesn't look exactly the same (e.g. custom armor / outfit, or you can choose a different character / party each time you play)"
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lgu6ax | How are video game AIs programmed? Is it a just a long series of "If Then" statements? Why are some AIs good and others terrible? | Technology | explainlikeimfive | {
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"There are multiple ways to do it. Generally your if-then statement is close to reality. (Often it's Event based, to allow changes when new information is available rather than static checking what to do once previous commands are finished). Having lists of priorities is also common, to let the AI take the most important of the currently available options. AI skill is hard to get correct depending on the game. Strategy games are notorious for having terrible AI because it lacks creativity to adjust to any strategy the player might choose. In other games a good AI easily outclasses even pro players when not carefully reduced to human reflexes/perception Making a very good AI without allowing it to cheat (having more information than the Player for example) is a lot of Work and rarely done because just cranking up the numbers also makes the game harder for the Player without any effort for the programmers.",
"I read about a really cool simple AI in the old 8-bit Micro Machines racing game. The entire track was covered in invisible arrows. The computer controlled cars would just go in the direction of whatever arrow they happened to be on. When you shove a computer car off the track or push it behind an obstacle, it would literally be sitting on instructions on how to get back into the race.",
"Traditionally most simple AI's aren't necessarily just a chain of *if* statements. Rather, you would look at the actions an actor can do and calculate a motivation for them to do each one. The highest motivation wins. For instance, in The Sims, you might have a motivation score for Hunger, for using the bathroom, and for a few other things. Over time the motivation scores for hunger and bathroom go up until you're more motivated to use the bathroom or to eat than to do other tasks. You can make any specific motivation score as complicated as you want. Maybe your motivation to use the bathroom is higher when you're in proximity to one, so if you're going from A to B you might decide to use the bathroom on the way.",
"Different games require different AIs. AIs in a game like Dark Souls are basically complex If-Then statements. The enemy takes in their position, the enemy position, maybe a few other variables, and chooses a move to execute based on that, usually with some random chance in so it's not too gameable. AIs in a game like Total War are much more complex. There are many more factors that it needs to keep in mind, and often times the AI just can't handle the sheer amount of decision making. A big thing to keep in mind is that AI's need to run in realtime. in a game like total war, the AI could be made to be better, but then the calculations might take so long that the AI can no longer run in real time and you get a pause in the game frequently as the AI would need to make a decision. But that isn't fun gameplay.",
"As with anything involving programming, you can do it however you want. A common one is called a \"finite state machine,\" where you store a block of code in the current `state` variable (look up \"function pointers\" if you are interested in doing it yourself), then every frame you tell the game to run whatever is currently in the `state` variable. If certain conditions are met, then you swap out what's in the `state` variable with new code for a different behavior. For an example let's use a turret enemy. It rotates back and forth until it sees the player, then it shoots the player until it can no longer see them. In this case, we would have 2 states: Idle and attacking. We start with the code for \"idle\" stored in `state` which rotates back and forth, then checks if it can see the player. If the player is spotted, then it sets `state = attacking` and the next frame the attacking code is run. The attacking code will attack until it loses site of the player, at which point it will set `state = idle` and the cycle repeats. I don't know how familiar with code you are so I tried to keep it as close to ELI5 as I could, but if you want more detail I can. As for why some are good and some are bad, that's more of a design issue. It's like asking why some movies are good and some are bad. With games it comes down to knowledge of what makes an enemy fun to fight, programming skill, and time spent programming. Sometimes things are rushed, or the programmer just didn't care and we end up with a bad AI.",
"Or by \"machine learning\", which is just the programmer programming the AI to play the game itself before playing vs human. Example - I made a hangman game. The \"ai\" can play the game itself but starts with only the alphabet. It takes guesses in sequence, noting a correctly guessed letter each time and the word + word length each time it dies. By the end of 1000 iterations, it guesses the correct word 70% of the time. It always starts with 'e' as it came up the most times in its previous games. To make it more efficient, you would add extra 'lists' to be filled and keep track of, like word length x letter used - narrowing down the selection to choose from. You can then go further - after every successful guess, search your word list for matching words. And so forth. In the end, it is just the program storing information in different ways that is then used.",
"As said by others, it's mostly IF-THEN, together with ranking the possible options and taking the one which has the best \"value\". Machine learning is also a possibility, but up to my knowledge it is rarely used by major game companies. & #x200B; > Why are some AIs good and others terrible? 1. Games with secret information (like fog of war in wargames, hidden hands in cards games) are much more difficult to handle that games without secret informations (like chess). This mean that a common problem for AIs is that they \"forget\" informations they had 5min ago but they no longer have access to.Often, the devs just chose to make the AI cheat by looking at the secret information, and compensate by making the AI play suboptimally so that the player doesn't realise the AI is cheating. The more difficult solution is that on top of handling the current state of the game, the computer has to handle all the different informations that are known by the AI, and try to make deductions. 2. Games in real time give a huge advantage to AIs compared to turn base games. The AI can effectively act instantly thousand of time per second, so unless the devs willingly reduces the AI's capability to a more \"human-like\" level, the AI is potentially OP. 3. On the other hand, a lot of games have absurd amount of informations, which our brain is much more effective at approximating than AIs. There might not be that much difference for you between a game where you move from a square to another square (like chess) and a game where you have continuous movement (like Starcraft), but that's a huge complexity overload for an AI. 4. Having a stupid AI that cheats and have big bonuses (like free resources, etc) is much easier to code (allowing the team to focus on new contents, bug fixing, and DLCs), and the huge majority of players don't see the difference. As such, a lot of companies publish their game with very poor AIs. This is even more the case for games where it is assumed that experienced players will play against other humans, not AIs.",
"For a non ELI5 version, I would read up on \"behavior trees\". To summarize, you can just think of the kids of activities the AI does, and then imagine how you would decide to switch between activities. The switching is basically an \"event\" that happens, and ultimately you detect it with some if statements. But as the programmer you write a tiny function that triggers the event with if statements, and from then on you think of it as an event instead of the if statements that created it. Activities and Transitions * Patrolling - Starts in this mode. This is further broken down into sub steps, that basically boil down to: * Walk to the next spot in the route. How it does this isn't part of the AI, it's just a pathing algorithm * Once within some short distance of the goal, change what \"next spot\" means to be the one after that * Chasing - Once the player is detected, move toward them. This uses the same pathing algorithm as patrolling, and may choose to have them run by setting the move speed faster. The faster movement is one signal to the player that they are being chased. You can also enrich the experience by having the AI say, \"hey!\" or something. If they become undetected, chase where you last detected them. If the AI gets out of range of some distance or zone, revert to patrolling, which means find a path from wherever you are to the next patrol point and start walking, and maybe say something like, \"must have been the wind\" * Fighting - If you are in combat range of the player, do whatever abilities you have. Often there is a minimum time between any actions, called a global cooldown, and a minimum time between the same action, which is the action cooldown. This prevents them from doing everything at once and controls how often. You can make a whole behavior tree within this space to include things like evading or hiding when you are reloading or whatever. You think about this the same way you do this overall tree. This is a structure for one way you might design an AI. The behavior tree is an algorithm that lets you organize the activities of your AI in a way that mirrors how we behave, and it doesn't have to be that complicated for it to appear intelligent superficially. Gamers often observe the AI and start to recognize the patterns and learn to manipulate the AI to unintelligent things. When you break down any pattern or algorithm in computers, at the finest grain level it is all a bunch of if-else type statements, because at a processor level, testing and branching depending on the result is the fundamental way to control program flow. We often build up base patterns or algorithms to let us think about it in a more convenient way even though at a low level the test and branch pattern is everywhere.",
"As an AI researcher that plays a lot of games in my spare time, this always baffled me. From what i have gathered the state of the art in the games industry are still decision trees, which are as you describe it, simple if than statements. Those work great for first person shooter enemies, overarching directors, like in left for dead 2 the number and intensity of zombies spawning, and the alien in alien:isolation. So why is this the case? Why not simply train up a good network that will be better than all the decision trees you can come up with? After all, we can basically play dota and starcraft at pro level now with enough resources. The answer I gathered from multiple videos and thinking about it myself is, that in games, gamedesign is always king. You can only ever have really smart AI if the gamedesign allows for it. Take the Alien from Alien:Isolation i.e. You do not want it to be smart, because if its only goal where to kill the player, the game would not be fun. You also want it to be predictable, so that the player can learn its behaviours. A trained AI however will not play \"fair\" and predictable, so to speak. If you give it a goal, it will kill you, it will do so in the fastest and unfairest way possible and the end result is you not playing the game anymore, because you died 6 times in a row without any counter. You could probably make the alien more stupid, by restricting the information it gets, but now you need to basically balance the game in an indirect manner and bugfixing will be a nightmare. Imagine the balancing act multiplayergames have to go through but for a singleplayer game that needs to be ready and fun on release and also adding all the exploits a godlike AI can find in your game on top of it. & #x200B; The only time where an actual smart AI would be useful is, when it is supposed to mimic the way a human would play. This could be the case in computer controlled enemies in multiplayer games. But this is almost the only case, where you want actual smart AI. If you are interested in the topic and want to dig a bit deeper, I highly recommend the following videos/youtube channels: Gamemakers Toolkit: What makes good AI. [ URL_0 ]( URL_0 ) & #x200B; AI and Games: Behaviour trees 101 [ URL_1 ]( URL_1 )"
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lgussy | Advanced concepts of Big O with examples (except O(n), O(1)) | Technology | explainlikeimfive | {
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"If you wanted to sort a list of numbers, one of the simplest ways you could do it is to find the smallest number, put it at the beginning, find the second smallest number, put it at the second position, and keep repeating until the list is in order. Finding the smallest number is a ***O(n)*** task, because it takes longer proportional to the length of the list you're searching, and you're repeating the task ***n*** times. So this form of \"insertion sort\" is ***O(n^2)***. If you used a more efficient algorithm, breaking the list apart in clever ways, sorting the sub-lists, and recombining them, you could get the total time down to ***O(n log n)***. The explanation of why it's less than n^2 is a little hard to explain so I'll leave it out unless you need it, but the point is that \"divide and conquer\" is a good working strategy. If you wanted to solve the \"travelling salesman\" problem, of how to plan a trip to n different cities with the least travel time, searching every possible combination and ordering of cities would take ***O(n!)*** time, which quickly becomes enormous. That's why it's really important in such problems to find a good heuristic to use that might ignore better possibilities, but will give you an answer that's close to the best answer, in a fraction of the time."
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lgvw0i | What is Diffie–Hellman key exchange protocol in Messaging App. | Technology | explainlikeimfive | {
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"Diffie-Hellman is a way for two people to share just enough information that they can each generate a secret key for use in encryption but not enough information for an eavesedropper to also generate that key. A good analogy is paint. Paint is easy to mix but impossible to unmix. You and I each secretly choose a paint color. (Let's call those colors A and B) Then we each decide and agree on a public paint color. (We'll call this color C). Then we each mix the public color (C) with our secret color (A and B). At this point I have a mixture of A and C and you have a mixture of B and C. We exchange our mixtures. Since paint is impossible to unmixed, anyone witnessing this exchange cannot extra A from AC nor can they extract B from BC, even if they know what C is. We then add our own secret color to the mixture given to us by the other person. So I add A to the BC you gave me and you add B to the AC I gave you. In the end, we both have the same mixture: ABC. Diffie-Hellman does this, but with math. The mathematical operates are chosen to be easy to do in one direction, but extremely hard to undo. That way, you and I can exchange information and perform mathematical operations that independently give us the same answers, but an eavesdropper cannot extract the appropriate information from our public exchanges to do the same thing."
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lgvy49 | How is end to end encryption actually safe? Can't someone just steal the key? | Lemme explain my question. Disclaimer: My question would sound like a 5 year old's explaination itself but bear with me. Say I was texting my friend on a service that is "end to end encrypted" so basically when I hit the send button after typing, it locks it and the key to the lock is with only me and my friend. **But,** a hacker can just find the key because our service made it for us so there must be a universal 'recipe' to make that key that the service uses throughout everyone's chat and the hacker can just find the recipe and make the key. Making a random key wouldn't be useful since I would have to 'tell' my friend the key and the hacker can just intercept that. So how on earth is it possible to make something completely unreadable to others? | Technology | explainlikeimfive | {
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"It's called Public Key/Private key encryption. The service you are using gives each user a Private and Public key. It's randomly generated, but the public keys stored on their servers so that they can make the communication work. The way Public Key/Private key encryption works, is that if I want to send someone a message, I encrypt it using their public key. Then when they receive it, they decrypt it using their private key. Only the private key can unencrypt the message. So in your case, your app will ask their servers for the public key of your friend. Then use that public key to encrypt your text message. Your friend's app will use it's private key to decrypt the message. The private keys shouldn't be stored on the server for maximum security."
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lh38pu | What exactly is a voltage controlled amplifier, and why is it important? | We're working on a VCV board in my class, connecting a ton of cables to make sounds, and the teacher stressed the importance of VCA. He said that audio source and envelope generators multiply to create audio output; why is this important? What exactly is VCA anyway? | Technology | explainlikeimfive | {
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"VCA = Voltage Controlled Amplifier. You can think of a VCA as basically an automated volume knob. An audio signal is passing through it, being volume-controlled by a control voltage signal. a high control voltage turns the volume up, a low CV turns the volume down. Volume control is very important in synthesizers, because it lets you determine the \"shape\" of a sound - like whether it should have a short, sharp attack, or a long, slow swell."
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lh80o5 | What is ray tracing in video games? | Technology | explainlikeimfive | {
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"Even though it looks like they do, games don't usually simulate light actually starting from a light source and bouncing around a scene. Instead, they use a number of visual tricks (like normal maps, which give surfaces 'texture', or ambient occlusion, which makes distant objects look more faded) to simulate the rough appearance of a real scene. Ray tracing is *actually* following the light rays from light sources as they bounce off different objects. This is very computationally-expensive and requires good hardware to achieve a decent framerate, but it's also much more realistic looking."
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lhc7h5 | Why is it so difficult to make synthesized instruments sound like their real-world counterparts? | Technology | explainlikeimfive | {
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"First, I want to suggest that your experience might be coloured by 'availability bias'. If you ever hear a synthesized instrument good enough to fool you, then, more or less by definition, you won't know you've heard one. One pretty popular brand of synthesized and sampled acoustic instruments, is the Native Instruments Kontakt line, and you can listen to previews of many of their soundpacks here: [ URL_1 ]( URL_1 ) Instruments like these are used extensively in movie soundtracks as well as other music. I bet that lots of them will sound pretty real to you. & #x200B; But why is it hard to do this in general? The answer is a bit different for each instrument. Fake pianos started to sound a lot more convincing a lot earlier than fake guitars, for instance, because there isn't all that much playing nuance to capture in a piano note. The note can be struck hard or soft, and it can be held long or short, and that's just about it. Two parameters, velocity and duration. In piano playing, all the expression and nuance doesn't come from fine details about the note itself, but from how they're put together. A single note on the guitar, though, can have all kinds of inflection on it - picking technique, fretting/voicing, bends, tremolo, all that stuff. It's a lot more work to come up with a simulated model of a guitar which captures all those things about someone's playing style. And even if you \\*have\\* come up with a convincing virtual instrument model, that doesn't necessarily mean composers and players will know how to use it effectively. Most music composition and production software has a quite generic, non-instrument-specific approach to writing out melodies and chords. There's no standard way, for instance, for a composer to tell a virtual guitar instrument, which chords should be strummed upwards and which should be strummed downward. People using these instruments might have to manually edit their compositions note-by-note to add tiny minuscule timing offsets to simulate strumming, since if all 6 notes in a guitar chord are struck at exactly the same time, it will sound unnatural. It's the same for many other instruments, like saxophone or violin, which allow for a huge number of different ways to play a single note. Most computer and keyboard-based composition workflows do not have good ways to expressively simulate those technique nuances. Edit: Here are some examples of [wind controllers]( URL_0 ). If you wanted to get a convincing synthesized saxophone sound, controlling it with one of these would be a must. Playing the sax line on a piano keyboard or drawing it out on a sequencer grid just wouldn't cut it.",
"Professional musicians playing actual instruments do so many things to add a little character to their sound, from how they articulate the note (hit it really hard at the beginning or let it kind of fade in or all things in between), how long their notes last, which ones they play louder (if you listen to most any melody lines played on instrument, especially in jazz, they very rarely play every note at the same volume), the timing of the notes (you can very subtly move notes over rather than having a specific grid aligned to the beat), tonal choices especially with horns, and other small things like that. Maybe it's possible to program that much personality with a computer, but at that point it's cheaper to just hire a musician. A song that really demonstrates what I mean is [Always and Forever]( URL_0 ) by Pat Metheny. Listen to the amount of detail in the guitar solo and listen for the things I mentioned earlier, and you'll see why it's so hard to replicate."
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lhdev3 | the differences betwern analogue and digital for storage information | Technology | explainlikeimfive | {
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"Emma and Madison are field goal kickers on their (American) football team. Every day they go to the practice field and practice kicking field goals, and as one of their challenges they try to beat their personal best distance record. Emma keeps track of her distance using a long rope. She ties one end of the rope to the goal, and every time she successfully makes a goal, she ties a knot in the rope corresponding to where she was standing. Madison instead looks at the yard lines, adds the distance between the end zone and the goal, and records the number in a log book. Emma is recording a analog measurement. Her distance is not recorded as a number, it's recorded using a physical object. Over time, that object might degrade or stretch, and that might make it difficult to determine the exact distance as accurately as the day she took it. Madison is making a digital measurement. The number itself isn't necessarily more or less accurate than Emma's, but once she writes down a measurement, like 46 yards, there's absolutely no question as to what measurement she made. The number is written down clearly and precisely and there's no chance someone would misread her notebook as saying 45 or 47 yards. So again, digital isn't necessarily more accurate or precise. But it isn't subject to degradation over time as anything physical is. A film negative is analog. Over the years the colors might fade and the material might degrade. A digital photo is made up of pixels on disk. 10 years from now if you open the same image file it will look exactly the same as the first day it was taken. The file is digital; the color of every pixel is stored as a number that doesn't degrade over time."
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lhf4u9 | Why does making movie cost so much money? | For example, Endgame’s budget is $356 million. What are the cost of it? Also for animation movie, for example, Frozen 2’s budget is $150 million. It might sound stupid but I really need to get it out. If the entire movie are made in computer, why is it cost that much? | Technology | explainlikeimfive | {
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"It takes a lot of people to make a movie. Pay attention to the credits and you will see how much people work in the process of making it. Aside the millions the actors earn, there are other hundreds of people working. CGI demands expensive hardware and software and there are other production costs. They must travel, rent places, etc. Marketing costs a lot in order to make a successful movie, and we can't forget the distribution costs.",
"For animated movies you need very capable (and expensive) people running very powerful (and expensive) computers almost 24/7. For example: To render 1 frame of the movie monsters & Co. That contained Sully (the blue hairy monster) they needed 24 hours of rendering ON ALL THE COMPUTERS OF PIXAR, that's because every hair has to interact with air, gravity, inertia and every other hair in a way that is modeled by very talented (and expensive) mathematicians. For the movie frozen pixar had to create a new mathematical model of snow that allowed them to do iper realistic avalanches, [this helped solve a mistery of 60 years ago]( URL_0 ) The Ray-tracing tech that we want in videogames was used in movie making first. Most often than not, all big production have to pioneer some technology to make the film they want, this is often extremely expensive.",
"For endgame: there are a LOT of A list actors there, all their fees. There's the other people: look at the credits. There's like 1000 non-minimum wage people working for *years* on it. Other actors, costume, makeup, location scouts, lighting techs, sound techs, editors, CGI and effects crews, props, set designers and builders. And then support people getting fruit trays and water bottles for all those 1st people. And everyone in admin and HR and custodial and security staff at the studios, its all baked in to their cost. Then there's physical stuff: renting locations, renting sets, renting sound stages, building materials, props, a hundred top tier PCs for rendering all the CGI, all the lighting and microphones and camera equipment. Then there's distribution, making thousands of copies of the film and shipping them around the world. Then there's marketing. Showing the trailer on hundreds of TV networks around the world means buying hours and hours of air time. Paying for the actors to travel to promo events. Paying for the venues and promo events themselves. Making Endgame isn't just like \"pay RDJ a few K and buy a camcorder\". It's an industrial scale years long megaproject with thousands of \"moving parts\" around the world.",
"Lots of people work on a film. Some of them (director, lead roles, stars, DoP, editor, producers, writers... everybody \"above the fold\" whose names you see in the opening credits) are really expensive. They are expensive for many reasons, because they are good at what they do, because they attract audience (so-called star system), because each of those names is actually a team of personal assistants, trainers, coaches, whatever... Then there is an army of people needed to make a film. See end credits. Not all of them work through the entire production (preproduction and postproduction included) but still, they do work for some part and paychecks do add up during a couple of years that the project spans. Extras are not payed much, but there can be a lot of them. And when you have lots of extras, shooting takes time. Then there are unsung heroes that are not even credited but that cost money. People that maintain and keep the studios and production houses running. Security people. Drivers. Janitors.... There are offices to be payed for, electricity bills, computers, office supplies.... Locations to shoot, whether sound stages or external, cost money. There you also need a hell lot od electricity. And gas for vehicles. You also need to rent tech. And to pay insurance for it. And to have people to operate and handle it and drive it around. All the music and sounds you hear (and there is lot more of it than you notice) is payed for. That all goes for a simple drama, present day, no stunts, no vfx. Go do something out of this time and place and bills pile up. And so on and on... Once you have your film finished, you need to distribute it and do the marketing. For big hits that usually cost the same as the production. You also have to pay taxes for all that."
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lhgisv | How are media and album Sales counted? Are they counted when the stores buy them or when the costumer buys from the store? | Technology | explainlikeimfive | {
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"Depends what data you are looking at. Billboard uses a point of sale tracking but requires retailers to opt in. RIAA (gold, platinum etc) uses wholesale shipments, not retail sales. Streams or digital sales are counted in different ways (ie 10 single song purchases equals one album sale, even if it's the same song 10 times)."
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lhilaq | In what ways are Android phones less secure than iPhones? | Technology | explainlikeimfive | {
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"Apple only lets you play with toys it gives you. Android also lets you play with anything you bring on your own, including knives, bleach, raccoons, and anything else you can get your grubby little hands on.",
"It's a pretty common case of freedom against security. Both android and iPhones are the top runner in the category (smartphones). As a result, for any competent hacker, bypassing either of these phone's security is a big deal, because it means a large amount of targets. But android and iPhones have very different ~~politics~~ policies in how to handle development on their devices. Android try to follow windows: Open as much as possible. They want to appeal to the devs. \"Making an app on our device is easy, fast and rewarding\". As more devs go to android because its better for them, they have more apps than iPhones. They have more possibilities. On the other hand, iPhones do the opposite: Close as much as possible. You need an uncommon programming language, certification, and pass test to have your app allowed on their store. Not only that, unlike android, you can't install an app without the store. This lead to much less apps, but also to potential censor. But it also mean that it's very difficult to get into the device when you have bad intentions. It's trading security for freedom. And that is only when it come to the security issue, there are some proprietary issue with iPhones, also about the right to repair. But that's another topic. Edit: Correction from politics to policies.",
"Apple limits what you can do with your phone. Android gives the user more options. With more options also comes the risk to do something wrong and compromise your system. Examples: on an Android you can install software that's not part of an appstore (where they get \"vetted\" in a way to try to ensure there's no malware in them), on an iPhone you cant (unless you jailbreak it, I think).",
"Basically iPhones have something called a Secure Enclave (SE). This is a separate part of the chip that even the operating system can't access. It runs its own little stripped-own operating system that can only perform certain functions, has its own data, its own area of encrypted memory. When you set up your phone, the SE holds all of your encryption keys. When you set a passcode it creates an encryption key based on a combination of the phone itself and of your passcode. The same passcode produces different keys on different phones. The keys never leave the SE, the OS has no way to access them. So you let your iPhone record your face for unlocking. This is converted into a numerical representation, and a call is given to the SE to accept a new face definition. You have to enter a passcode first to do this, so the SE verifies you are the authorized user before accepting this new face definition. Then when you go to unlock, the phone sends whatever face representation it sees to the SE. The SE then either responds negatively, or it hands over a derivative of your original encryption keys to unlock the phone and access the data. It's actually a lot more complicated than that, with various key exchanges, but that's the short of it. That's just one example of how the SE makes it secure. In 2015 Android phone maker HTC just left your fingerprint as a graphic on the open file system. The OS matched your finger read to that graphic to unlock. Zero thought to security there. Apple had released their first phone with an SE two years earlier. So one of the basic problems is the question of whether YOUR phone maker really cares about security. Not all Android makers necessarily do. I hear some have copied the SE concept since then, good for them, but they're still playing catch-up. Otherwise, as noted by others Apple runs the whole OS. You have one vendor that tests the security of its whole product. All apps run under it with limited privileges. Your Android may have many third-party apps running with system privileges, and that really isn't good for security. This doesn't mean Apple is perfect of course. There will always be vulnerabilities in any OS that hasn't been mathematically proven (and that's only really possible for a small OS)."
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lhmuf6 | Why is source code being leaked for a video game a big deal? | Technology | explainlikeimfive | {
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"text": [
"the source code is the recipe, the product you buy is the cake. just because you have a piece of cake in your hand doesnt mean you can determine how the cake itself was made. however if people have access to it, they have a much easier time finding exploits/hacks, use the code to build their own versions of it and make money from those, etc.",
"Code for games is compiled, or translated into binary and obfuscated (or obscured) as a result, if you try to decompile it then it will still be unreadable (to a human). Source code is the human readable version of code, and would allow someone with malicious intent to find a vulnerability that would allow them to modify the game in ways the developers didn't intend."
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lhr978 | What happens behind the scenes when files are transferred from a USB to another? | Do the files get temporarily saved on the computer and then get transferred to the second USB? Is it the same when files are transferred from a USB to a cloud service? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Exactly how it is done depending on the exact implementation of the operating system. I would expect that the way windows do it is to read the data from the USB drive into a disk cache on memory and then write it to the other drive from memory. If it is a small file it might be completely read into memory but if it is large files the it will start writing it before it has read all of it. So the file is stored in RAM in the computer perhaps not all of it at the same time but it all will pass through the RAM. For a cloud service, the answer is that it depends on the cloud service. It might be that it read from the USB to RAM and upload it. But it is not unreasonable that in some cases the files are temporarily coped to the drive on the computer and uploaded for it. That is so you can remove the dive and the computer can upload it in the background. That is something you would like to happen if you for example upload files from a camera so it does not need to be attached to the computer for a long time. So you can copy it to the drive of the computer but you do not need to. You do need to read it into the computer memory to transfer it."
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lhskb7 | How do websites permanently ban users? | I'm aware of how websites can just straight up ban users, but how would they *permanently* ban a user, such that any visit to that website is 'detected'? IP address or some such? | Technology | explainlikeimfive | {
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"text": [
"Part of connecting to a website means telling the website where to send the page to. This has to involve your IP address, or the IP address of the VPN you're using. If the connecting IP is on the blacklist, then you won't get connected.",
"Pretty much, yeah. The most precise is banning their account. Less precise is banning their IP address (this could potentially ban an unintended person, but at least you're more likely to also hit the target too). Even less precise is banning a *range* of IP addresses (you're even more likely to ban unintended people, but even more likely to hit your target too)."
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li0lbd | How did the CIH virus manage to write data to a computer's BIOS and destroy it? | I've been reading about the CIH virus, which was a very destructive virus from 1998-1999 that would overwrite the BIOS code on your computer with junk data, basically bricking it and making it unable to start. But how exactly did it write to the BIOS chip? Apparently, it only worked on the Windows 95 and 98 kernel. Isn't the BIOS chip on a computer protected? Did computers back in 1990s have no protection for the BIOS and just let anything write code to it? There's not that much information other than "ring0". & #x200B; The source code is here, it's written in Assembly: [ URL_0 ]( URL_0 ) | Technology | explainlikeimfive | {
"a_id": [
"gn0kel4"
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"text": [
"All regular computers can write to the BIOS; they need this capability to upgrade the BIOS firmware. The question is just \\*how\\* do you write to the BIOS. CIH used a particular write-enable function that worked only on a subset of BIOS chips available at the time, so it didn't always work but it worked enough. CIH was doing exactly the same thing that your BIOS update program does today...which is why you want to be really careful about where you get BIOS firmware files from."
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li1hbk | Why does a high quality picture/video taken of something look better than seeing it in person? | Technology | explainlikeimfive | {
"a_id": [
"gn0qwuk",
"gn15flx",
"gn0wghv"
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"text": [
"In professional photos, every light source is placed carefully to make the subject stand out, only a few pictures are selected fom hundreds, and some editing is done to make the picture look even \"better\"",
"It is possible that you need glasses. You may be noticing that your eyes can focus on a near screen much better than a distant scene. Or it may be that digital cameras are getting better at automatic processing and make objects look a little hyper-real.",
"It has to do with how your eyes focus. Human eyes have about 575 megapixels of resolution, but only in the exact spot we are focusing on. A high end photo camera can have around 60-70 megapixels, but the focus cone is much wider than what the human eye is capable. So while the human eye is technically higher quality, it's only able to be high resolution on a small area. Plus cameras can zoom and magnify images easily, making the image's details more pronounced."
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li22sv | Why do non English original language films have vastly diferent translations between dub and sub? | Technology | explainlikeimfive | {
"a_id": [
"gn0p0t5",
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"text": [
"Subtitling and dubbing have their own separate set of rules. Dubbing is more strict on the duration of the sounds and matching it with the lip movement, whereas subtitles have a limit of characters. Source: I’m a translator by education. I don’t work in TV or cinema though, so I’m not that well versed on this subject.",
"There are several reasons. For reasons, most of my knowledge of this comes from anime, so all the examples are coming from that. One factor is that the voice actors are trying to match the flaps of the lips, so if a literal translated version is too few syllables, they’ll retweak it to fit. Another factor is audience. If you’re watching something like a Hayao Miyazaki movie, the dub is usually targeted to kids while the sub will mostly be seen by older teens and adults, so the dub may change certain cultural references that a kid might not know about. Pokémon was notorious for this."
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li4mu0 | How do sites avoid accidentally banning innocent people? | So I was just thinking out a scenario. Person A comes onto a site and causes problems. They get banned, their IP is logged and they leave. They get a new IP and continue about their business. Person B is assigned an IP which happens to be the one that person A was using. Person B tries to join the site. How, if at all, is the site able to tell that Person B is not a trouble maker? Would person B be locked out by accident? Or am I missing something? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"They don't, necessarily. Investigation is always needed when something like this is going on, and people don't wander around the Internet with \"I am John Doe, my Social Security number is xxx-yy-zzzz, my address is blah\" taped to them. So if a site is banning SOLELY based on IP addresses, then yes, dynamic IPs can cause bannings to apply mistakenly, or to mistakenly NOT apply. Similarly with only looking at email addresses, only looking at username, etc. -Dave, whooooo are yooooou? asked the Caterpillar"
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li6w1o | How did old dial phones figure out where the call is going without having a computer inside? What is the mechanism behind the dial? | Technology | explainlikeimfive | {
"a_id": [
"gn1hb0m",
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"text": [
"The old, rotary dial telephones were just a small part of a much more complicated machine - the local telephone switch (local being local to a small town or several large neighborhoods.) As part of the greater machine (local switch), and in order to minimize the number of individual wires connecting the handset (rotary telephone) to the larger switch, a signalling mechanism was used involving completing and interrupting a circuit with multiple voltages, both AC and DC. When a call was received AND the phone was “on hook” (such as the receiver being in the cradle), the local switch would send a high voltage AC signal to activate the bell[2] , at around 20Hz. Once the receiver was picked up (the phone was “off hook”), the local switch would detect that and stop the ringer signalling. The mouthpiece in the receiver (the part you spoke into) was a “carbon microphone”[3] that would change the electrical resistance with the pressure waves of the sound impacting on it. This change in resistance would produce the analogue electrical signal representing the voice of the speaker. Conversely, the sound from the other end was impressed on the pair of wires at a higher frequency (than the ringer). A system of passive electronic filters made of inductors, capacitors, and resistors separated the mouthpiece signal from the earpiece signal. In order to make a call, the receiver would be lifted off the cradle, changing the phone from “on hook” to “off hook” state, completing the DC circuit. The local switch would detect this (and would usually provide feedback as a low frequency buzz.) The local switch would connect the phone circuit to a “stepper” switch. Operating the dial would (quickly) switch the DC circuit at a fixed rate (frequency.) This frequency was low enough that it was possible for some agile people to actually make phone calls by tapping the cradle “hook” button fast enough, with the right timing. (A parlor trick for nerdy teenagers.) This fixed rate of on-off switching is the “pulses” of pulse dialing[4] . In the original design, it caused the stepper switch[5] to step through it’s various positions and then (usually) proceed to connect to another stepper switch. These stepper switches were electro-mechanical and hideously complex (for the time - and even for now.) The sheer physical size and number of these stepper switches needed for each subscriber line, the number of cross connects needed, etc. meant that most of these switches didn’t support more than 5-digit dialing.",
"there are two legacy way for older thelephone to compose a number: pulse signaling and tone dial. pulse signaling, more often found in phones with rotary dial, flip the hang button as many time as the number you put: if you want to call, let's say the number 123, it will create the following electrical pulse on the \"hang\" wire: - -- ---. Tone signals instead produce a sound, a note for every number you digit directly on the voice wire: it's the \"beep\" you hear when you're composing a number. today provider sides calls are all routed on various VoIP networks but for compatibility there is a device between your old phone and their network that take the duty of converting those electrical signals into digital signals that can be managed by them."
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li77ze | Why do microphones make a high pitched sound when they're close together? What causes the sound? | Technology | explainlikeimfive | {
"a_id": [
"gn1i7q0",
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"text": [
"It's not when you bring two microphones together, but when a microphone gets too close to a speaker that's playing directly from that same microphone. And you also need an initial sound to set it off - in complete silence it would never start. What happens is that the microphone picks up a sound, which then gets played through the speaker and so the microphone picks that up and it gets played back through the speaker etc.etc.etc. this causes the sound to keep getting louder and louder. The squeal is caused by the particular amplification profiles of the mic and speaker, and the particular position and orientation they are in relative to each other. When all of those things come together to mean that higher pitched elements of the sound get picked up and amplified better than others then it keeps making it higher and higher pitched with each loop as well as louder.",
"It's a feedback loop. They're recording themselves recording themselves recording themselves recording themselves ad infinitum"
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li7pik | Why does it take an hour to install a game but seconds to uninstall? | Technology | explainlikeimfive | {
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"text": [
"When you delete a file, most of the time the only parts being deleted are the parts that say the file exists. Most of the data sits there waiting to be overwritten by something else. This is why you can recover deleted files. Run a format or a multi pass overwrite deletion on something the same size as a game and you'll see it takes just as long.",
"Installing is like writing stuff on pages in a notebook. Afterwards you also write the new entries into the table of contents. Uninstalling is like striking through the relevant entries in the table of contents. As you can imagine, the latter act takes significantly less time.",
"Deleting a game basically removes links to the game and tells the computer that the current files for the game can be overwritten any time you need more space, it doesn't immediately remove all the files for the game."
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li8f1f | I am wondering how the concept of time was first discovered and how? When did human began using “time” in their activities? | Technology | explainlikeimfive | {
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"text": [
"It happened far too long ago for us to know for certain, but early hunters would have judged that after/around dawn would be a good time to start a hunt.",
"so to my knowledge it al started somewhat 2000 b.c in ancient egypt. Egyptians first used the sun dials to measure time, thus they measured the time from sunrise to sunset and divided them into 12 parts, and then, the need to measure time in night-time pushed them to invent sandclocks and water clocks, the accuracy of these methods weren't high but they did the job. as for the actual concept of time i think it was clear from the start, that there is time, ancient humans noticed that the shiny thing in the sky is moving and it eventually goes down and comes back up. the \"time machines\" were first invented in Europe in the 13th century."
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lidafx | What kind of 'bots' are captcha preventing? | Most captchas are on websites where you have to create an account for something. Are captchas preventing some kind of automation scripts that create multiple accounts on a website? What are some other reasons that captchas exist? | Technology | explainlikeimfive | {
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"Captcha is meant to deter the usage of any bot, in that they're designed to require human interaction in order to pass the test. Bots can be employed for many purposes, such as mass purchasing of products, en-masse account creation, post creation/spamming, or repeatedly accessing a web page as part of a DDOS attack. A captcha doesn't necessarily prevent these activities from happening, it's just meant to make them more difficult by requiring human assistance to complete, which largely defeats the purpose of the bot in the first place."
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lidafy | console vs pc | Why is it readily available to have a modded or hacked game to enjoy on PC while consoles very rarely have hacked or even modded games? | Technology | explainlikeimfive | {
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"Not saying it's truly black and white but - two aspects - 1. Console makers have a tremendous amount control of the content used on their systems. Since all PS4s are made by Sony, using Sony software, playing games using Sony's proprietary game network system it's easy for them to a. keep out mods and hacks from being available to its users and b. to detect and deter hacks that do make it through. Hacks/mods can be used to import viruses/malware and also make the game less fun for other users, both serve to drive casual users away from buying more Playstations, so there is an incentive for Sony to guard it's software. 2. PCs are not as centralized, they are cobbled together by parts made by numerous manufacturers, running software that's just as varied. So it's harder to for anyone to act as a controller of the content being played. If people hack a game to the point it's no longer fun for casual users, those users aren't going to suddenly stop buying Motherboard X or monitor B, or even to switch from Steam to whatever bullshit EA offers. So no party has an incentive to play gatekeeper. There is also a selection bias. The overlap of users who know how to create, source, and employ mods, set up their own networks for play, and actively want to be part of the mod making/using community also generally like to build their own rigs and not be burdened by a controlling agency, so they tend to be PC users rather than console users.",
"Because consoles are designed specifically to try and prevent unwanted modifications to their games. Console developers are free to put all sorts of elaborate anti piracy right into the design of the console itself and build their games to match. With a PC, the system itself doesn’t come with that type of dedicated anti cheat, it’s a general use device so devs are on their own to figure out how to secure their pc games."
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lifth4 | how are we able to have hundreds or thousands of wireless devices sending and receiving signals within range of each other without any of those waves going through the air interfering with one another and corrupting data? | Technology | explainlikeimfive | {
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"gn2vvod",
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"First of all, there's very few cases where there's literally hundreds of thousands of devices attempting to operate on similiar wavelengths in an area similiar to the effective range of those communications. If you think of a worst case scenario like an absolutely packed mega-event, you'd have maybe 60,000 people in a small enough area where they'd be connecting to the same for example, 4G services. In any case, all digital wireless communications protocols have built in error detection and correction methods. In short - every time you DO use anything wireless even if it seems like it's working great, there are corrupted packets that are being discarded. The worse the signal and the noisier the enviornment, the less packets of data that get through unscathed. For the most part, you don't notice the difference because the theoretical maximum bandwidth of 802.11ac is 6.9Gbps - Are you really going to notice a huge difference if it's only working at ~1/7th capacity (1Gbps), especially if your home internet connection isn't even that fast?",
"The premise of the question is not correct because the radio waves do interfere with each other. If you and your neighbours have two separate WiFi networks on the same channel or even a nearby channel for the 2.4 GHz band and devices transmit at the same time can be the case that the access point cant read the packet and it needs to be retransmitted. The interference will not result in data corruption because you have checksum on the data that is transmitted so you can detect if there is transmission error and then the data is retransmitted. Wifi devices do listen to what is transmitted and will not star sending a packet if someone else is transmitting at the same frequency at high enough power. The system works as if you have a group of people that talks. When there is a plus something two people start to talk at the same time but then you stop talking and after a short pause then someone starts to take again but start over again. The result of interference is lower bandwidth, not data corruption. The range of WiFi is quite short by design so a lot of separate networks can be quite close to there and work even if there is a limited number of channels. & #x200B; If you look at mobile phone network then you have a regulates system where each operator has a frequency range the can use. They will then set up the networks so to transmitter direct beside each other do not use the same frequency but you reuse it farther away like [in this picture]( URL_0 ). The cellular network also has a quite short range just because of this reuse of the frequency-time and time again. It is called cellular network because you build it of a lot of small cells. Multiple phones will use the same frequency and communicate with the same tower but you use a clever way to encode the signal so multiple devices can transmit at the same time and the receiver can receive all signal at the same time and get out all the data. It is called CDMA and is a bit like how you can hear two people speaking over each other and still pick out what they say."
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liid9k | Why does light go into black holes? | If light has no mass why does it get sucked into black holes? | Technology | explainlikeimfive | {
"a_id": [
"gn3bgk5",
"gn3bb2x"
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"text": [
"Gravity doesn't pull on light the same way that it pulls on masses. But gravity isn't just an attraction between masses, it is more properly understood as a warping of spacetime. What this means is that while an outside observer might see light as being bent around a black hole, from the point of view of the light it is always traveling in a straight line as it feels no attractive force from gravity (not having mass). Instead space itself is bent, such that a straight line near the black hole isn't parallel to a straight line a greater distance away. Light is pulled in and trapped by the black hole because space is warped in such a way that there are directions that lead into the black hole but beyond a certain point there are no directions that lead out. This point of no return is called the \"event horizon\".",
"Another way to look at is that light follows the plane of space (this is really simplifiex) and black holes warp that plane. Think of a bed sheet pulled tight across a bed. You roll a golf ball across the middle it it will just go in a straight line. Now, if you place a bowling ball on the sheet, when you roll the golf ball, it will roll closer to the bowling ball becaue of the depression it makes. The \"depression\" in space that black holes make are infinitely deeper than the bowling ball on the bed."
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likc1j | Why is commercial air travel still the same speed it was 60 years ago? And will it ever change? | Technology | explainlikeimfive | {
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"It did get faster, we had the Concorde, which was super sonic and heinously expensive to operate. That’s really what it is. We’ve optimized aircraft from a cost vs speed perspective. Can we go faster? Hell yea. Is it cost effective or affordable? Not really. Source: am an aerospace engineer",
"[Because transonic drag (Mach 0.8-1.2) is awful]( URL_0 ) Around 80% the speed of sound the drag on the plane starts to skyrocket, going from 80% to 90% can be a 3x increase in drag which results in a 3x increase in fuel consumption which results in a massive increase in ticket cost. Once you get beyond about Mach 1.2 though drag starts to drop off. This region between Mach 0.8 and Mach 1.2 is the transonic region and its when some of the airflow is supersonic (pinch points and tight curves on the plane) while others parts are subsonic and it creates this real mess. This is why planes either fly well under Mach 1 or well over. Jet airliners have been running in the Mach 0.75-0.85 range for over 60 years now, that's as high as they can practical go without breaking the sound barrier which is a no-no over land, that's why they've instead been focused on fuel efficiency to reduce running costs There is research into Quiet Supersonic jets but its still quite experimental and a few decades off. Until we can get rid of the damaging sonic boom overland flights have a pretty firm limit at Mach 0.85",
"The problem is that we started to approach the sonic barrier. The effects of the speed of sound starts to show itself in some areas at around 80% of the speed of sound. This is because the air needs to move around the aircraft body and the wings and may therefore have to go faster then the speed of sound in certain places. The problem is that when you start getting these areas of air going faster then the speed of sound you start getting a layer of high pressure air clumping up in front of the aircraft. At lower speeds this high pressure air will be able to move forward away from the aircraft but not when you start getting towards the speed of sound. The problem is that this high pressure air is pushing the aircraft back. That creates a lot more drag then normal flight. You therefore need a lot more power and use a lot more fuel to fly closer to the speed of sound. And is there anything commercial air travel does not like it is to use more money on fuel. At around 80% the speed of sound is usually the most fuel efficient speed. Fly slower and you have to spend more fuel because the flight is longer and fly faster and you have to spend more fuel because of the increased drag. There are a few aircraft that is designed to fly faster. Of course the Concorde was designed to fly faster then the speed of sound. By going faster then the speed of sound you get rid of a lot of the issues with drag however you still need to use about twice the fuel in normal cruise and a lot more fuel punching through the sound barrier. So the Concorde was very expensive and required big fuel tanks compared to its small cabin. The price was not really its problem as its clients were not looking at the price themselves, however the cabin size was a problem. But there are a few private jets which can go faster then most commercial airliners. There are several that goes about 90% the speed of sound and a few planned ones designed to go supersonic. But these do require people who are rich enough to want to spend the massive amounts of money on fuel at these speeds.",
"Travelling faster requires a lot more energy and that means more fuel, it is possible to build an aircraft surpassing that of Concorde, but it would be expensive to build an operate and the demand for very fast aircraft isn't there.",
"> Why is commercial air travel still the same speed it was 60 years ago? And will it ever change? Supersonic commercial flight was [tried out]( URL_0 ), didn't prove to be in enough popular demand to be deemed profitable and was abandoned again.",
"One of the reasons is simply diminishing returns. Crossing the ocean in an old sailing ship could take months. Crossing the ocean in a steamship took a week -- saves the traveler 4-5 weeks of travel time. Crossing the ocean in a plane takes hours -- still saves the traveler a week or more. Crossing the ocean in a supersonic plane is insanely expensive -- only saves a few hours. We reached a point where the time saved isn't worth the extra expense, at least for most people."
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likx37 | How did people copy something from a VHS/cassette tape since they're physical..? | Technology | explainlikeimfive | {
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"All digital files are copied from an original. All analog files are copied from an original. The original file will usually have a few backup copies made for redundancy in case it is damaged, but it will also be handled with care. Even in the digital age, you will occasionally hear that a company has lost a shitload of money because they have accidentally lost some important data.",
"You got it right, there is a MASTER copy out there somewhere and they would set it up in machines that would copy the master to thousands of other tapes at the same time. Technically they would use the Master-master to create Master-copies and then make the mass copies from the Master-copy, all to protect the original Master-Master. They protected the heck out of that master because if they lost it, there could be problems. In a few famous cases the masters of various albums, TV shows, movies, have been lost or destroyed and those are simply.. gone. An entire season of Dr. Who from back in the day is lost because the studio recorded over the master with a soccer match I believe, although I think they've found a few random bits. Interesting fact, in some cases the master is a higher quality than duplicates they produced at the time. For example old movies filmed with actual film. When they make 4k HD versions of these films now they can go back to the original master and get the increased definition straight from the source.",
"There were special machines used for duplicating VHS tapes. They used thermal magnetic duplication and could copy a tape at up to 900x faster than real time. You need a machine like this one here, plus a few others: URL_0 First you have one machine that you feel the video/audio signal into and it creates the master. You load the master into the 2nd machine, and it spits out recorded video tape at high speed. A 3rd machine takes the newly recorded tape and loads it into the video cassettes. 20 years ago, expect to pay about $500,000 for a complete setup.",
"You may find [this]( URL_0 ) useful. It's for audio tapes but it's similar for VHS. TL;DR: They're recorded to multiple tapes simultaneously onto HUGE reels at faster than normal speed and then chopped up.",
"There is a “master copy” of everything. There’s an original. Copies are made, and every copy is just a duplicate of the original. There are often a bunch of 1st copy ones saved in case something happens to the “master”. You could, once upon a time, just connect two VHS machines together and just play from one and record onto another. This wasn’t perfect and the copy wouldn’t be as good. It’d be barely noticeable. But you wouldn’t have the types of quality machinery than they do in factories where copies are made en masse. These days things are all digital so you just burn another one onto a disc. Records are actually all analogue still, so records are copied - from record to record. Decent records (vinyl discs) shouldn’t ever be burned from a digital file."
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lil7sp | How do bits in a computer become meaningful to human beings? | Technology | explainlikeimfive | {
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"gn3rfv0"
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"text": [
"Bits aren't meaningful. What they produce is meaningful. If I use the bits in a computer to generate a picture of my wife on a monitor, then I will value the computer and its \"bits\" for being able to provide me something valuable to me. I don't care about the bits themselves. No one does. They are only tools in a process that creates things of value."
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limcg0 | What’s special/different about 5G? | Technology | explainlikeimfive | {
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"text": [
"Videos playing faster isn’t really the point (though it’s a minor point). The main point is that 5G can handle more users in crowded spaces like concerts and sporting events. (In the beforetimes, crowded spaces were when our phones stopped working even though we had service because towers were overwhelmed.) It will also be able to provide short distance super high speeds. So, maybe you have a park that gets 5G millimeter wave (which is what it’s called). Eventually, that tech will roll out to more places than just a few parks. Adding bandwidth enables new capabilities. There’s much bigger files out there than YouTube videos. Maybe people want to use AR in the park or businesses want to transmit high quality 3D scans of construction work. Streaming video games and other programs will require lots of bandwidth.",
"Using a higher frequency of radio waves lets you pack more data into the signal. Imagine sending a message with beeps, but not like Morse code. Instead, there's a constant one beep every second. You can *modulate* your beeps to send a beep every half second instead. So, \"beep beep beep\" would be 000 and \"beep beepbeepbeepbeep\" would be 011, and so on. This limits your data speed to one bit (0 or 1) per second, since you have to wait a full second each time to know if it's a 0 or 1. If you instead increase the speed to ten beeps per second for a 0 and twenty for a 1, you can obviously send data way faster! Similarly, the radio signal is a wave that goes at a certain frequency, and you can modulate the frequency to increase it or decrease it slightly to indicate a 0 or 1. A higher frequency means more data. One problem with this is that if your \"beeps\" are too rapid, and the difference between the two speeds is too small, you might not be able to hear the difference between them. Similarly, a higher frequency is a bit harder for the receiver to decipher. That's not a big problem, though, and modern technology has advanced enough for devices to be able to figure it out. The other big problem is that for physics reasons higher frequencies don't travel as far. They get absorbed better by stuff, especially water, which the atmosphere is full of. Walls and trees aren't helping, either. To overcome that, you need more towers that are closer together. That becomes very expensive very quickly. Like the early days of cell phone coverage, some places just aren't going to get 5G. And in fact, this is the same reason that some places even in the US *still* don't have 4G or sometimes even 3G coverage. The other way to solve this problem is to make the receiver more sensitive. That has its own problem - it will also pick up more radio noise, so it needs to be able to filter the noise and find the signal you're trying to pick up. As you've probably picked up by now, 5G uses a higher radio frequency so it has a higher bandwidth than 4G - *much* higher bandwidth. Phone technology is good enough now to be able to detect a weaker signal and filter out the noise. Service providers also have more existing infrastructure to add antennas and are willing to invest to build the additional infrastructure needed so there's enough coverage. With these advances, 5G could give the kind of internet speeds you normally only see with on a decent connection at home."
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lipbs7 | Why is black plastic unrecyclable and why is it still used? | Saw a utube today explaing that machines cant "see" black plastic used as food trays etc. If so why not change the colour? | Technology | explainlikeimfive | {
"a_id": [
"gn4hriv"
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"text": [
"Because if a manufacturer thinks that a black tray sells their product better than that is what they will use. Recyclability of packaging will only be a consideration if it becomes a selling point in itself, which is slowly happening."
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liriye | Why do we recognize CGI when we rewatch a movie years after seeing it the first time? | I went back and watched Avengers: Age of Ultron for the first time since it was originally released and for the first few scenes all I could focus on was how noticeable the cgi had become. I have vivid memories of being blown away by how realistic everything looked when I saw it years ago. As special effects technology improves, does that mean the way we recognize those effects also improve? | Technology | explainlikeimfive | {
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"text": [
"It's because CGI gets better and better slowly so we don't notice the change as much over time. Then when you look back at old stuff you have recent far superior CGI to compare to the less advanced stuff."
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lit6gz | I know many rice cookers use fuzzy logic (or fuzzy math?) So it cooks the rice the right amount of time. How does this work? | Technology | explainlikeimfive | {
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"text": [
"The basic ones are a bit simpler than “fuzzy” logic. Water can only stay liquid up to 100 degrees C. While there is liquid water in the cooker it’ll have a max temperature of 100C. Any excess heat put in gets used to turn the water to steam. When all the water is absorbed or evaporated the temperature can climb above 100C The cooker has a temperature sensitive strip on it that triggers just over 100C. This could be fancy circuits or it could be a bi-metallic strip with the right thermal properties. When all the liquid water is gone and the rice temperature goes above 100C the sensor trips and turns the cooker off.",
"Fuzzy logic in mathematics essentially allows for degrees of truth. Instead of binary choices like \"is this hot, or is it cold?\", in fuzzy logic something can be sort of or almost hot. So for advanced, computer-controlled rice cookers, using fuzzy logic allows them to move beyond the binary choice of the basic rice cooker (is it done, yes or no) and make decisions on how to cook the rice based on what's happening during the cooking process and how it is programmed to respond.",
"You don’t need fuzzy logic to cook rice properly. It’s just one of many control systems which are available on the market. The basic idea is to use the same logic as a non-fuzzy system would use (is there enough water? Did I heat it to the temperature when I should turn off the heater? Did all of it evaporate? Is it still warm enough to serve?) and introduce a bit of shades of gray in the chip’s reasoning. So, for instance, where a non-fuzzy system might continue to heat the rice because the temperature is not exactly right, drying it in the process, a fuzzy system will correctly handle a situation where the rice is _almost_ at the temperature but _barely_ started to dry up."
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liuzgg | teeth whitening kits | Can anyone explain to me how the teeth whitening kits that shine a bright bluish/purple light on you teeth work? How do they make your teeth whiter? For example, “Smile” was a popular one there for a while, and I believe Crest has one now as well. I assume that they must work... otherwise someone would have surely compared their teeth from a month before treatment to after and figured out there wasn’t a change. So how does that all work??! If someone can explain the science behind all that, it would be awesome! I attempted to search for some sort of answer on this forum for something similar, haven’t found anything. If there is one, please let me know. I’ll be sure to take this one down! Thanks! | Technology | explainlikeimfive | {
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"text": [
"It's basically bleach, usually peroxide based. Oxygen transfers from the peroxide and attaches to stuff that stains teeth breaking it up and fading the color. The kits that come with lights use UV light to make the process happen faster, in a similar way that heating chemicals tends to make for a faster reaction. They still rely on a paste of some sort though. Definitely works well in a dentist's office, but I personally have no idea if the UV light in at home kits actually does anything. The dentist light is going to be a lot more intense, and a more energetic wavelength of uv is used that requires eye protection. The at home kits light is going to be safer and weaker so it really might just be a gimmick, and the kit may work just as well without the light. They do work though the effect is going to be a lot better if you only want to go from heavily stained to lightly stained. Getting to pure white is usually pretty difficult. Especially because if you use the kits too often they can weaken your teeth pretty badly."
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livuuo | how GPS satellites handle a huge amount of requests? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"GPS satellites don't receive signals, they emit signals (and is always the same for everyone). Your GPS device must receive signals from at least 3 different satellite in order to calculate your position using a technique called trilateration. Each gps satellite has a known position in space (any given time) and his signal allows your device to know your particular distance to that satellite. Using the same information from other two satelites allows your device to calculate your position. So basically the magic is done in your device",
"GPS satellites constantly broadcast a signal to any device that's listening for it. Your phone doesn't contact the satellite. That signal says the current time according to the satellite. If a phone receives that signal, it can compare the time according to the signal to the time on the phone's clock. Based on how out of sync they are, it can calculate how long the signal took to reach you, and therefore how far away the satellite is. With three satellites, the phone can do some math and figure out its current location."
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liwi3p | why does the wii remote work when you put fire in front of it? | URL_0 | Technology | explainlikeimfive | {
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"text": [
"The Wii bar that you put near your screen is just two infra red LEDs, the Wii remote has infrared receivers and is just looking for an infrared source, because anything hot is an infrared source all it needs to be is hot enough."
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lj1w2s | What does a GPU do when you play a game. | Technology | explainlikeimfive | {
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"For your computer at home, games are harder to run fast than the other things you're probably asking it to do. There's a lot of math the computer does in the background trying to figure out where all the stuff in the game is and how it should look on your screen. If your computer can't do all that math test enough, the game will run too slowly to play and it might not even run at all. The GPU is an assistant that does all that extra math for your computer. It's really good at doing geometry - calculating angles and stuff, which is the kind of math that games need. So it does as much of the extra math involved in figuring out what goes on the screen so the rest of the computer can keep doing the rest without getting overloaded.",
"A GPU is a Graphics Processing Unit. It processes the graphics for the game. It's a chip that's specialized for doing lots of relatively basic stuff, which is good for graphics processing. It puts all the pixels on the screen. Meanwhile the Central Processing Unit processes everything else, like where the monsters are going and how many health points you have. The CPU tells the GPU \"display a monster at these coordinates: 123, 456\" and then the GPU actually translates that instruction into pixels. Some old game consoles used to have a Sound Processing Unit, but these days the CPU is fast enough to calculate the sound as well, so it doesn't need a separate processing unit. Not all games use the GPU. The CPU can process anything, even graphics. The GPU just processes graphics more quickly and lets the CPU do other stuff in the meantime."
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lj6al1 | How does a neutron bomb work? | Technology | explainlikeimfive | {
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"A modern nuclear weapon is usually a fission-fusion-fission design. That means you use a fission reaction to get enough energy for a fusion reaction and then use the neutrons from the fusion to get even more fission. That can give you a really *tremendous* kaboom in a smallish package. For a neutron bomb (aka an Enhanced Radiation Weapon) you skip the last fission stage. Instead of absorbing those neutrons and using them to make more kaboom you let them go screaming off into the world to fuck shit up. The benefit this gets you is that you get a relatively small (for a nuke) blast, with a relatively big deadly radiation distance. This is useful if the thing you are trying to kill is heavily resistant to blast effect (like a tank) or very hard to hit (like an incoming nuclear warhead). In practice the only actual deployment of neutron weapons was as anti-ballistic missile systems, because that's where they really shine.",
"In theory, a neutron bomb emits a blast of neutron radiation which incapacitates or kills all the people in the area leaving structures undamaged and minimal residual radiation so the attacker can quickly move in and secure the now vacant infrastructure In practice, it doesn't really. For anything bigger than about 10 kT the immediate blast radius is far greater than the radius of lethal radiation so they have to be made from very small devices. For a 1 kT \"neutron bomb\" the radiation would be 100% lethal in a couple days out to 900 meters and 50% lethal out to 1400 meters. Oh and this device would completely obliterate non-reinforced concrete structures out to 600 meters and would take out all wooden buildings to about 900 meters so only the area between 900 and 1400 meters out is kinda cleared of people and kinda not destroyed, inside 900 meters is pretty damaged and outside 1400 meters is relatively unhurt. The idea is based around the fact that both Uranium fission and fusion of tritium give off a fast neutron (turning the lithium fuel into tritium gives off another too) so you can have those neutrons deal with weak organics. The neutrons can also be used to trigger other near by nuclear devices (like an incoming hostile nuke) but similar to taking out meatbags, it has to be really really close to the target to do that reliably ( < 100 meters)"
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lj8ji4 | When TV's had no display and were a static screen (black and white dots), what causes the static sound? | Back in the day (mostly) when you had nothing plugged into your TV you would get a black and white static screen with a static noise. What causes the noise? | Technology | explainlikeimfive | {
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"Are you asking specifically about the sound? The sound and the pattern are two sides of the same coin. Normally, a TV would be receiving a signal of information for picture and sound. When there's nothing connected or the signal isn't good, the TV picks up on random bits of electromagnetic noise, like stray waves from a microwave, or something with magnets moving. About 1% of this stray noise is actually the remnants of the Big Bang. The TV does it's best to interpret this 'signal' and make a picture and the appropriate sound. But the signal is rubbish. Instead of being a clear patterns of 1s and 0s that make, say, a face and the sound of someone talking, they are totally random. So, you get splodges of light and dark, and a hiss known as white noise. This is the auditory equivalent of the 'snow' you see on the screen. Crucially, when the TV is properly tuned to a source, that noise (both visual and auditory) is still there. It's just that the real signal is so much stronger that it gets drowned out."
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ljql9w | Why does infrared light from remotes only work on the TV it’s assigned to? | Technology | explainlikeimfive | {
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"The infrared light isn't just like a flashlight, it is blinking specific codes to tell the television what to do. Those specific sequences of blinks are different for different manufacturers so the remotes are not interchangeable. There do exist universal remotes which can change their blink behavior to emulate a variety of different manufacturer codes.",
"They don't.. IR remotes from one model of TV can be used on any TV off the same model. If two of the same model of TV are next to each other, both TVs will act on the commands from the remote at the same time. IR remote controls send a series of flashes of IR light. TV's are constantly looking for flashes of IR light, but only act when the flashes of light they detect are exactly what they are looking for. It might be easier to imagine these flashes of light as beats of a drum. And TV's are listening for their favorite drum beat. All TV's of a certain model are listening for the same beats and so they will all act the same when they hear it. Different manufacturers teach their TV's to listen to different beats so they don't respond to other manufacturer's remote controls. Universal remote controls know the favorite beats of most manufacturers and that is why they will work with most TV's.",
"Remotes for any particular model will generally work for all devices of that model. A few rare products have a small A/B switch inside the remote and also on the devices so that you can buy two devices and have a different remote for each. Otherwise each remote controls both devices. Remotes are somewhat directional so you can limit this issue by carefully pointing them, providing the devices aren't too close together."
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ljvq0i | When people are on the news or a podcast how do the microphones not pick up the other persons voice if they are co hosts for example and right next to each other | Technology | explainlikeimfive | {
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"There are many different types of microphones that are designed to have their own way of picking up sound called polar patterns. Some microphones have a focused point so it only picks up the source directly in front of the microphone. These are called cardioid microphones. Some of them are designed for the whole room called omnidirectional.",
"* On the news, the other mics do pick up the other people. * But an audio engineer in the control room has an audio console that has a fader and mute button for each mic. * Since they also can see the teleprompter and have reviewed the script, they have a good idea of who is going to be talking and when they are going to switch. * So they can very quickly switch which mic is being routed to the broadcast. * As for podcasts, they mics they use are very directional and don't pick up a lot of noise that isn't coming from directly in front of them. * Also podcasts are heavily edited before they are published and the audio is cleaned up. * But when two people are talking at the same time there is just a certain amount of \"mic bleed\" that occurs."
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ljvudp | the difference between computer monitors and TVs, and why you don’t want to use a TV as your monitor | Technology | explainlikeimfive | {
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"In the old days (up to 2005ish) TVs and computer monitors were generally very dissimilar -- they used different inputs (RCA jacks for TV; VGA & DVI for monitors), and monitors generally supported higher resolutions & color depths. With the advent of HDMI, digital signals, and near-universal adoption of widescreen 16:9, the lines have gotten blurry. Net, if you have an HDTV that you can connect to your computer, and you like the picture -- great! No reason not to use it. And the converse is true. Got a big computer monitor? No reason why you can't stick a roku in it and use it as a 'TV' Everything the other posters here have mentioned about refresh rate and latency is valid -- but OP isn't necessarily looking to game at 4k and 144hz. If you just need some more real estate to keep email (or slack/discord/twitch/etc) open while you work, no reason why a cheap TV can't help.",
"Pixels per inch. Let's take two screens at 1920x1080 resolution. 20\" Monitor at this resolution is 110 Pixels per inch. But, a 35\" inch TV would be 62 pixels per inch. So, while you can technically use a TV as a monitor, details will be much lower. Also, the refresh rate (how many times per second the screen can put out a new image) can be very different (the TV would be slower).",
"Mainly input delay. Monitors are made to have a low input delay whereas with TVs it's not so important."
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lk2hj3 | Why aren't commercial airplanes faster? | Technology | explainlikeimfive | {
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"Flying close to and above the speed of sound consumes a lot more fuel per passenger-mile travelled (due to the need for the aircraft to be able to handle the forces involved and other factors)",
"How fast do you want them to be?"
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lk8fma | - Why can't film directors film a scene from every angle with multiple cameras and remove them in post? | Technology | explainlikeimfive | {
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"Even if camera removal in post were cost-effective enough to use, dramatic lighting really only looks best on one side at a time. If filming multiple angles is a necessity, it will usually need to be done with compromised lighting.",
"The trouble as well is that it is not just a camera and operator that would need to be removed. There are so many people, lights, cameras, cables, special effects, monitors etc. just out of shot in every scene. They can get multiple cameras in most shot but only from a limited range of angles. The post production of removing all of this stuff frame by frame (rough guess, 24 frames per second x 60 seconds per minute, x 120 minute movie is around 10,368,000 frames that need to be perfectly photoshopped)",
"it would additionally be more expensive. And if the cameras aren’t being properly used the scene would be more cold and the cinematography will be probably not what they’re looking for when they finally get a project",
"Your question insinuates that to 'remove everything you want out in post' isn't a difficult and costly process, performed by skilled digital artists – it takes a *lot* of time and care that those artists need to be paid for. *That*'s the something that you're missing. Your post sounds like you expect someone to just click a \"make it look like you want it to\" button and be done.",
"Lighting is *huge* part of filmmaking. Different lighting can make the same shot look completely different. You can photograph the same person with different lighting, and they would look different. Directors take a lot of care to make sure the lighting is exactly like they want it for each shot. The lighting, similar to the music, the sound, the camera movements, the acting, the dialogue, etc., tells the story in its own way. The problem with lighting is that you can only sometimes set it up for one camera. If you want to the light to come from the left side of the shot for one camera, then the light direction would be different for a second camera. This is why most shots are filmed with a single camera, because the lighting is tuned for that one camera angle only. In scenes were lighting is less of an issue, then you can use multiple cameras. The lighting is a reason why soap operas have that weird look to them. Because they film on multiple cameras to save time and money, they oversaturate the set with lighting. Because of this abundance of light, the shots look odd when compared to properly lit shows and movies."
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lk8q3z | Why do iphones pause at 80% charge instead of 100% | Apple has an optimized battery charging mode where if you keep it on, your phone stops charging at 80% while you sleep and starts changing again from 80 to 100% before you wake up Why not just have the phone charge straight to 100% and it stops there? | Technology | explainlikeimfive | {
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"Li-ion batteries don't like being at the extreme ends of their voltage range. If they're below say 20% or above say 80%, the batteries will age much faster. By stopping at 80% and then finishing the charge before the phone gets taken off the charger, you make sure that it doesn't spend more time at 100% than it absolutely needs to, so you extend the life of the battery a bit."
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lklicd | how are people able to hack into webcams and spy on other people? | Technology | explainlikeimfive | {
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"Because the people who set them up, don't use secure passwords, and so when a hacker finds the device they just try commonly used passwords, and get in. People are warned over and over to use secure passwords, but they don't because its hard to remember. Also, many companies have 2 factor authentication, but people don't want to be bothered with it because they are lazy. Only you can protect yourself."
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lkmlbe | How do radio waves get "encrypted"? | If radio waves are just non-visible light waves that are picked up by a vibrating rod, how does a radio wave get "encrypted" so that it can't be picked up unless it's unencrypted? Edit: Everyone keeps commenting that the content of the message is what's encrypted, not the radio waves itself, but that's not what I mean. Someone answered that digital signals themselves can be modulated or disguised, which is what I meant when I asked | Technology | explainlikeimfive | {
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"The content that they're holding is encrypted. Let's take a basic Caesar shift. Every letter in a phrase is shifted along the alphabet by a predetermined amount. So if I start with the phrase \"explain like I'm five\", I'll get \"hasodlq olnh l'p ilyh\". I transmit that over the radio waves. The receiver on the other end knows to expect a Caesar shift, so they undo it and get the original phrase. In Networking we actually divide the entire end to end communication into seven distinct layers. Layer 1 is the physical transmission medium (i.e., radio waves in this case, ethernet cables in others, etc.). That layer is only responsible for the contents of it's own layer, and anything else beyond it can be swapped out for anything else without any changes. The encryption would be at a much higher layer that doesn't really care about the medium that carries it.",
"The medium is not encrypted; the *message* is encrypted. The simplest way to send an encrypted message via radio waves is a [numbers station]( URL_0 ) \\- using a radio to send a message which is meaningless gibberish to everyone except the intended recipient.",
"The radio wave isn't encrypted - anyone can receive it. The *information* encoded in the radio wave is encrypted just like any kind of digital information can be encrypted.",
"A lot of people here have answered this, but I also want to add another method of \"encryption\". Its called have-quick. Basically two radios sync up according to a gps time signal and hop frequencies while transmitting in a predetermined pattern. Unless you know the pattern and programmed the radio with it, the most you could receive is fractions of a second of the message.",
"The wave itself isn't encrypted, the data you're encoding in the waves is encrypted. Someone can still intercept the communication easily but without knowledge of how it was encrypted (the algorithm) and any keys used to encrypt it being in their possession, it's just random unusable garbage to them. Easiest example of this is encrypted wifi - it's still just broadcast out in the clear but unless someone has the network key, they can't do anything with the data they intercept."
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lkpls1 | Why is it bad when a game developer has lost the source code to game it wants to rerelease/remaster? Isn't all the data needed in the original retail copies? | Technology | explainlikeimfive | {
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"The code distributed to users isn't the original source written by the authors, instead it's a compiled machine code that can be run by a computer. In an analogy, think of it as a cake. You can't figure out the recipe just by eating the cake.",
"Another analogy would be to music. You can have all of the notes written out and instruments picked out and singers can have all of their lyrics ready to perform, but once that music is all put together and recorded, the final 'mix' is just that - a final mix. Yes, with technology, you can digitally manipulate music once it has gone on to the final mix, but if you wanted to change some notes in one particular instrument or change a lyric, you would have to rerecord that part and make another final mix. If you were to lose the 'files' containing these instruments or notes (aka the game source code in this analogy) that would mean that you cannot go back and change one or two things simply without totally recreating every other piece of the code as well. Hopefully that made sense.",
"Games created from the mid 90s onwards will most often than not be written using a high level language. These languages are easily read by the developers but not by the computer/console, therefore it will need to be translated (compiled) into a computer readable form called machine code. The downside is that machine code is hard to understand compared to the original source code. This is due to the fact that many useful features from the source code are missing, like comments and named variables. When a game is released, only the compiled machine code plus any extra files that the game may require are present. The source code could potentially be used to aid piracy so it usually isn't included. Some games may contain files that can be decompiled back into the original source code, though finding these files can be quite rare. If a developer loses the source code and wants to rerelease or remaster the game, they only have the compiled machine code and any decompilable file they can find (which in most cases will be none). They will have to run the machine code through a disassembler which will turn it into assembly language (low level programming language), then work through it all and see what everything does. This process could take months or years depending on how big the game is, and is generally not a task worthwhile doing. So when a company loses the source code, their best option is to remake it from the ground up which will cost precious time and money that could have been saved had the original not been lost. As for my analogy, think of it like building a house. An architect will have a blueprint for a house which will be used to build said house (compiling). If the blueprint is lost then the architect still has the house as a reference point (machine code) but it will be easier to draw up a new blueprint (starting from scratch). TL;DR: People translate sentences into a foreign language, they lose the original words and the foreign version won't easily translate back exactly as it was, so they recreate the sentences from scratch.",
"Think of it like cooking a delicious meal. The final prepared meal is the game, and the recipe that lists the ingredients and cooking instructions is the source code. With the recipe (source code), it's easy and straightforward to recreate the meal whenever you want. Without the recipe, it would be almost impossible to do so. Sure, a great cook could probably guess many of the ingredients, but they would still require a lot of trial and error to find the right proportions of ingredients and cooking instructions."
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ll4arn | Why should I care that Google and other tech giants have my data? | Technology | explainlikeimfive | {
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"Because you have almost no say in what Google does with it. Sure, it might might OK if they sell it to a company who uses it to show you ads for things you actually like or want. But what if Google were to sell your website browsing info to your health insurance company? Say you were looking up a place to go skydiving, and your insurance company saw that and decided you were a high-risk individual to justify raising your premiums? Or what if your mortgage company obtained data that showed you were looking for a new job, and similarly decided you were a risk and raised your rates? The controversy about data harvesting is that we *don't know* what's being done with our sensitive personal data- the process is immensely opaque- and the potential harm from having your personal data out there for the highest bidder can't really be estimated yet.",
"Its also about you as a thinking, feeling person, but as data points. Everyone is correct that the true trouble is that we don't know what they're doing but think about how much the tech giants know about your: -eating -sleeping -passions and prefetences -sex drive/interests -locations you frequent -political leaning and intensity of opinions -your inner social circle -and so, so much more The giants can build a better profile of you and everyone on earth than a thousand Private investigators ever could. This data has been used to fix and sway elections through triggering people's psychological reactions to real issues, with fake stimulus. I.e. \"vote for X because Y did THIS! CAN YOU BELIEVE IT?\" And our stupid lizard brains simply must engage at some level because the content is specifically built for and streamed to your internet and apps based on all the data aforementioned. The Great Hack (hulu) and The Social Dilemma (netflix) Have good takes on these issues. Sure, \"nothing to hide, nothing to fear\" seems good on the surface, but ask yourself: if privacy isnt a default expectation of humanity, why do you always close the bathroom door?",
"Companies might buy said data and use it to discriminate against you in selection process for jobs. LGBTQ+ people might get accidentally outed just based on their search history. And many more cases like that that can have negative impact on your life. The counter-argument usually is that people that have nothing to hide have nothing to fear but just think how many things you DON’T tell everyone out of fear. That’s why we need privacy.",
"Data is a commodity that can be traded for profit. Now, compare this to oil... if oil is found on land you own, it's yours. You might not be doing anything with it, but others (like companies or the government) may have a desire to mine and use it. But, from what I understand, you have a right to be paid appropriately for resources like that found on your land, even if others extract it. With data, you have no such rights (for now, anyway.) Companies can harvest this resource from you and turn a profit from it without you seeing a single cent... which seems wrong, at least to me. It's data generated by you being active on the net, you passively create it, so as far as I can tell you should be entitled to some if the value that comes from it.",
"It matters what Google knows about you, first of all because there’s an assumption that what we do in our home is writing the realm of privacy. Google invades your privacy to build a vast stockpile of knowledge about your tastes, interests, habits, and even what you know and don’t know. Then, they use what they know about you to manipulate your behavior, showing you specific information to guide your decision making processes, and steer your behavior to make you easier to manipulate. Finally, they exploit your weaknesses to take your money, and the better they get at this, the more people they sell access to manipulate you."
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ll5wz6 | Why are MRI’s so loud? | Just had an MRI. Why are they so loud? Additionally. I could decipher about 12 different “tones/noises.” What does that translate to ? | Technology | explainlikeimfive | {
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"The machine generates an enormous pulsing magnetic field. Almost everything in the machine is as non-magnetic as possible, but that's not completely non-magnetic. Copper atoms, for example, react to strong magnetic fields. While the machine is quite sturdy, any possible flex will cause motion. Moving innards makes sound. The forces are large enough that you can hear the sound."
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ll6m7o | Why are telecommunications cables not all underground? | Technology | explainlikeimfive | {
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"Everything boils down to money. Switching from poles to underground sounds easy and logical on the surface. In reality it's very different. You have a utility pole in your back yard, utility company has an easement and right of way to it. That's long since established in your property deed. Switching that to underground means the utility needs to get a permit from the city, work with all the other lines on that same pole, like power/phone/cable. And some times even radio antennas for local citywide WiFi, emergency agency radios, mobile radios. Then the utility company shows up at your house, wants to tear up your fence and back yard to dig up the pole and bury new lines. Who pays go restore the fence, garden and maybe even that pool they had to dig through?",
"All F/O cables are underground, and the vast majority of residential and commercial internet is buried. They typically follow the sewer lines as cities tend to install 'conduit' when they dig and bury city utility since they know this is inevitable. This assumes a bunch of things, like you live in a city-like area and not in the boonies. Source - this is my job.",
"Because telephone poles came around first and when you already have the infrastructure in place, it's difficult to convince people to spend the enormous amount of money required to dig up the city/country to lay cables.",
"Putting cables underground means they're safe from the weather, for sure...but it also means they're a lot more expensive to install (since you have to rip up the ground and then fix it all when you're done) and maintain (because anytime there's a problem you need to rip up the ground, all over again, then fix it all, all over again) and upgrade (more digging, more fixing)."
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ll96q4 | Why do companies ask you to forward phishing emails to them as an attachment? | When you get a phishing email, sometimes a company will have a specific division that deals with that concern. So they'll ask you to forward any emails of that nature to a specific email address. But sometimes they ask you to do so as an attachment. Why? | Technology | explainlikeimfive | {
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"Because if there's any malicious code in the e-mail itself, having it separate as an attachment helps mitigate that. The IT department can open it on their own terms as opposed to opening your forwarded email that could then infect their systems.",
"This also retains the message exactly as it came in, since forwarding it normally could lose a lot of metadata especially if they want to inspect it closely."
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llct6f | How does binary trigger current in hardware? | I’m not very technical so apologies if I use terms interchangeably that don’t make sense but I will try to explain. What I understand and put very basic is: we write code, it then gets “converted” so that the computer understands it. This is represented by 1’s and 0’s that trigger current in the hardware that gets stored in memory, lights a LED, etc. through (I think it’s called) logic gates. That’s my ELI5 way of understanding it. What I don’t understand is how the current is triggered? What causes that interaction? For example, when I click save in a document. How does that trigger it to be saved in the hardware. Is it that, when I physically click on my mouse. That physical interaction of clicking sends a current and the computer recognises that the proportion of the pixels on the screen represents saving the document, which then triggers it to send that current to the logic gates? Edit: Thank you for all your answers. | Technology | explainlikeimfive | {
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"Is it your hand which grasps, or is it your fingers doing all the work? Is is software which puts those icons on your screen, or is it currents? The thing to understand about the computer is that it's *all* just electrical currents. All the logical, visual stuff you see represented on the screen and in the computer's abstractions ilke \"icon\" and \"desktop\", all of those things are just different arrangements of currents flowing through that big array of logic gates. So to ask how clicking the icon 'triggers' a current, well, it's just currents triggering other currents. That's really what a logic gate is, is a voltage trigger. There are various logic gates such as \"and\" gates and \"or\" gates, and their job is to trigger in a certain if-then scenario. It performs a rule like \"If input voltage A is high *or* input voltage B is high, *then* set output voltage C to high.\" The job of a CPU maker, is to wire these gates up to each other in ways so that physical if-then scenarios concerning the voltages on the wires between them, will map cleanly onto *logical* if-then scenarios that are useful for computation, such as the 'carry rule' for binary addition: \"if both addends have a 1, then carry a 1 over to the next digit.\" The software in the computer can be looked at in two different ways. Looked at in one way, the meaning of a particular software instruction could be: Store the value \"hello\" in a string starting at memory location 15. But looked at in another way, the meaning of that instruction is: \"Set the following voltages on the RAM data bus: high low low high high [...] high high\". It's kind of like the difference between saying \"write 'hello' on this piece of paper\" and \"deposit ink on the paper in the following shapes.\" The same physical thing is going on, but you're describing it at a different level of meaning. That's the difference between \"saving a file\" and \"triggering currents.\""
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llfsxj | What has actually happened to the power grid in Texas and how does green vs. fossil-fuel energy factor in? | Technology | explainlikeimfive | {
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"Mainly they have had to shut down power production because the facilities weren't designed to handle the cold weather. They use water to produce power in most places, and the water froze. And fossil vs green didn't factor in. 23% of their power comes from wind normally, and it all froze up because it also wasn't prepared for cold weather. All in all about half of their power production is off line. And since their grid is isolated from the rest of the country, nobody can help them.",
"A lot of things have actually happened to the Texas grid, going from how buildings are made to how power is transmitted and generated there. In Texas, the time of year when the most power needs to be generated at any given time is the summer. It's when it gets VERY hot and folks have to run their air conditioning for extended periods. So, because of the climate in Texas, most buildings aren't really shielded from the cold weather. This means that even though people may have heat in their homes, they might also be \"leaking\" a lot of that energy. Think of drafty windows, lightweight materials, etc.Second, because the winter is \"slow season\" for power generation over there, power plants may have been under routine maintenance or not have enough fuel stocked/purchased ahead of time. Finally, because this cold snap is so rare (and extreme), a lot of the power infrastructure has not been shielded from that kind of weather. Think of pipes bursting because the liquid inside is freezing, and even ice on power lines. Green vs fossil fuel power is not a super important factor, really. In fact, of the power generation that's \"out\", about a third is wind, and the rest is coal and gas. Meaning that most of the power generation that's current;y disrupted is not wind. More importantly, the issue is that temperatures are much colder than expected, and the operators of the electric grid did not prepare sufficiently. & #x200B; This article from USA Today is pretty good and cites local scientists: [ URL_0 ]( URL_0 )"
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llfv3z | What does the code that makes up programming languages look like? | Take a language like Java. How was it originally created? I can’t wrap my head around how someone invented a computer language to run without having some “prior” language that it allows the first lines to function. Is it just Java all the way down, like someone wrote a single line of Java and then every other line was built on that? What about the first computer language? What was the basis that that functioned on? Thanks for any help, I hope that was phrased in a mildly intelligible way. Edit; I’m trying to think of it like human language: at some point there was a first “word” spoken by someone and understood by another and from there the structure started to be born. What were the first “words” on a computer that led to where we are now? | Technology | explainlikeimfive | {
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"There are many different \"levels,\" to programming. (Warning, lots of words, but pretty simple) The lowest level of programming is transistors. We can build up simple logic gates such as AND and OR directly in the circuitry, and by turning certain switches on and off, we can get out certain behavior such as switching between different components, storing information, or doing simple math. These on and off switches can be represented as 1s and 0s or \"binary.\" **01010101 01001111 01101011** \\- > Would give the instruction \"store number 79 in memory slot 107.\" The first block (or \"byte\") would be the \"store,\" instruction, followed by the binary number for \"79,\" and finally the binary number for \"107.\" (the actual binary would differ depending on CPU architecture, so this is just pretend). Writing complex programs in nothing but 1s and 0s would be a nightmare, so instead we wrote just enough 1s and 0s to build a program that translates a more readable language called \"assembly,\" directly into the 1s and 0s we need. So instead of binary, we now write: **mov 79, 107**\\- > When run through our new assembler program, gets directly translated to the binary 1s and 0s from the first example. It basically just looks up what \"mov,\" translates to in a large dictionary and swaps it out for the needed binary. Basically just simple cut and paste. An assembler is a *very* simple program, but allows us to start thinking closer to human language, and thus allows us to develop more complex software. From there we can write a \"compiler,\" which is a program that can read over a text file in whatever language we want to come up with and translate that into the binary we need. **int myVariable = 79;** \\- > This gets read over by our compiler and translated into binary to be executed. This is how languages like C, C++ work. From there it's a self contained loop. A compiled language can be used to write new/better compilers, which in turn can be used to write new/better compilers, etc. Languages like Java and C# are one level above this. They aren't compiled into binary, but instead into \"bytecode,\" which is like binary but instead of being run by the CPU, it's run using either the Java Virtual Machine or .NET framework which are programs on the users machine designed to read this special bytecode. This allows the individual software developer (like you or I) to write a Java/C# program once, and it will work on any computer system someone has programmed a virtual machine for (most likely programmed in C or C++) which is designed to read these instructions. Finally we have \"Interpreted,\" languages like Python and Javascript which are the highest level. With these languages the actual text the programmer typed is what is sent to the end user, and the actual conversion to binary happens as each line is run on the users machine. This is why you can press \"F12,\" right now and see all of Reddit's code, since HTML5/Javascript is interpreted.",
"Java is actually run by a \"virtual machine\" entirely written in C++. So it's a pretty bad example. But C++ is being compiled by compilers entirely written in C++. How do you compile such compiler? Well, with an older C++ compiler! But, but, what about the first compiler? It was written in assembly, a long time ago. Although people like to bootstrap C++ from time to time, aka. start from scratch with a smaller language, easier to compile. But that's just for the kicks of it. By the way, did you know we need a mill to make a mill? Lots of stuff in the world is built on previously built stuff, it's kind of a fun chicken and egg problem. Almost all of them, originally started from painstaking manual work. Edit: It's even more fun when you realize C++ compilers have bugs, yet produce newer C++ compilers with less (hopefully) bugs.",
"The very first \"words\" on a computer were some poor, patient soul litterally plucking in every 1 and 0 by hand. They'd do this by baking it straight into the circuitry rather than programming it with a keyboard, because, well, how would a keyboard even work if programming doesn't exist? People still do this all the time, by the way. A common tool that lets you experiment rapidly is called a \"breadboard\", which lets you plug and unplug wires and simple chips to create complex circuits. After the first literal hard-coded computers were in place, they were extended to be more modular and accept arbitrary input from users via input peripherals, that could then be run as new code. Everything snowballed from there.",
"Many prior languages existed and some were similar to Java or c++. I am a retired mainframe assembly language developer, I did that in the 80-90s. Assembly was the first mainframe language, it's a step above the machine code executed by the chip. Assembly language is what many mainframe languages compiler generates as it's native to the chipset. Assembly is crude and rude, you better know WTF you're doing or bad things happen. Sometimes you can have to read and understand the machine code to debug your code. Principles of Operation is the reference manual for the language. ETA: One of our programs for class was to be written in machine code to demonstrate our knowledge of the language.",
"It's easy to build up a small sand castle with just a single small bucket, and this is like binary. If you want to build something amazing, though, you'll need to have more tools to make the job doable. You can technically use binary to create whatever you like, although it is much easier to program simple programs which encompass basic tasks like adding or subtracting. Then, using this new program as a 'frame' for a new program, you can layer on complexity (or remove complexity, depends how you look at it) for accomplishing more complex tasks. This is the difference between coding \"bare metal\" and using a high-level language like Java. There was a first word, but instead of thinking of it as a baby learning English, think of it as how humanity learned to communicate - we're talking ancient runic text instead of \"mom\" or \"dad\". Compared to programming, English itself is like a high-level language.",
"Don't think of it as a language, think of it as the evolution of a tool and its uses. Digging, for example. Originally, to dig one would use sharp objects. Eventually, the spade was invented, along with various sizes to accommodate different tasks. Larger tools for digging were invented until machinery allowed for even larger digging equipment and thus more tasks could be accomplished with this greater digging power. In the same way, programming started as soldering circuit boards, eventually moved to punch-cards and and tape reels. Then, with the advent of monitors and keyboards, people could do things like data entry and complex calculations and it just kept going from there.",
"ELI5 answer: It look very, very simple. The code that makes up programming languages itself is very simple. The language can then be quite complexe. Java is one of the worst example you could pick, because it is an interpreted language (this means than it relies on another programm, the interpreter, to run). But the codes that build it is simple. It starts with basic instructions: I want to add data. Instruction: add I want to store my result: store You might want to creat type: a byte might be an integer, or a character. Then, you need to repeat the same instructions in your language. You start to put a label at the start of your instruction: label my_little_routine Then you say that you want to go to your label again: goto my_little routine Then you say that this set of instruction should be used everywhere, so you create a function. This is a mechanism where you store your current data somwhere, then go to your label, then extract your data back from storage once you finish. You can use a compiler of compiler to create an advanced programming language out ofthese basic operations: [YACC]( URL_1 ) is one of them Modern languages implement natively many high level mechanism called design pattern, which is why you are confused: templates in C++, interfaces in java, iterators in python... These design pattern are common solution to frequent problems. So we grow programming language, from simple, obvious instruction, to a complexe toolbox. [Bonus track]( URL_0 )",
"The first general purpose computers were one-off machines. Their language were the lowest level opcodes, the binary bits that were used to drive what circuit paths the data inputs were going to undergo. There's an opcode to add two values, to multiply, to load from a location, to store to a location, etc... With that, programs were very simple and it was easy to think of programs in terms of CPU instructions alone. These programs were written in terms of punch cards or punch tape. The devices to do this had already existed due to the telegraph system. Indeed, Linux is directly compatible with telegraph teletype machines from the 1910s, you can see some guys on YouTube login to a Linux terminal on one. Of course, that doesn't scale. Eventually, especially by the later 1950s, computers already got large and powerful enough, not that programs HAD to get more sophisticated, but that they COULD. Then it became more valuable to manage the complexity by raising the level of abstraction from raw machine instructions to the first programming languages. They existed in private before 1955, but that was the year the first commercial languages debuted. I can't remember which came first, Lisp or FORTRAN. Both are still used today, and both represent nearly polar opposites of how to approach computation. FORTRAN is an abstraction of hardware, and Lisp is an abstraction of *a* calculus notation that can express computation, called Lambda Calculus. The first compilers and interpreters were written on punch cards or punch tape in machine instructions. Once the compiler was loaded, source code in that language was text encoded in punch cards. Again, this sort of thing already existed in the telegraph industry. ASCII encoding was developed for telegraph, and so ASCII and even unicode are both backward compatible with late telegraph development, hence why those early telegraph devices still work with modern computers. If you had a nice punch card key, it would even type, as a typewriter, the corresponding character on the card in ribbon ink. Each card would be a line of code, and you would try to cram as much code into a single card as possible. Verbosity was your friend when you had to keep thousands of cards in order. So instead of nice variables today, like \"velocity\", you would just use \"v\". It's a habit we haven't needed to have since the 80s and we've been trying to shed it as an industry since. Well, you get yourself a shiny new mainframe, and when you turn the hulk on, New York dims. Ok, how do you write programs for the damn thing? Well, you already have that other mainframe over there, with compilers and programs... Use IT to \"transcode\", to \"cross-compile\" a program for that new machine. Programs are just a form of data, and compilers merely interpret source code into *a* machine code, it doesn't have to be for the machine the compiler is currently running on, it just means the program that's output won't run on *this* machine. Ok, so then take your paper tape from that machine, bring it over to the new one, and feed it in. Bingo bango, you just compiled your compiler from source code to machine instructions for the new architecture. Now you can reuse all your source code from the other computers. Oh, you have a new magnetic storage device? Cool, skip the punch cards and store your data on that. Now you can just copy floppies and sell them. This whole process was repeated from scratch many times, because often enough it was easy enough to do in the early days. When the micro-computer was invented and people had their first Commodore 64s and ZX Spectrums, they even had interpreter firmware built into them. You could just boot them up with nothing and go straight into writing code, typically a form of BASIC or Forth. --- Java is a language that is compiled into a universal byte code. These are machine level instructions, but for no machine that actually exists. The machine is virtual, a fiction that exists as a spec document. Java compilers conform to that spec. When you run a Java program, the instructions are first interpreted, so the program can start running all the sooner. Meanwhile, the byte code gets compiled again (Just In Time(tm), aka JIT) into the actual hardware native instructions. The next time that code is executed, it switches over to the machine native form. The first Java byte code compiler and interpreter, because it didn't start out with a JIT, was itself written in Lisp.",
"The CPU only talks in numbers. Every number is an instruction. You have to know the \"codebook\" of what number, in what order, does what. Instruction 43 might be \"multiply these two numbers\", for instance. So 43 2 3 gives an answer 6. That number is literally represented in binary on the CPU's input pins when you want it to do something. You set those pins, they correspond to the binary for 43, and the CPU knows what to do next. But that codebook is a pain to program in. Ask the Apollo astronauts who had to calculate their trajectories, etc. by setting \"Verb 23, Noun 15\" on their computer system to get it to do, say, a basic multiplication instruction. That's all they had to communicate. Numbers. That's \"machine code\". But those numbers were assigned those tasks by the human CPU designer. So somewhere there's a codebook that tells you that 43 is multiply, for instance. So... why not let the human just use a shorthand. Say, \"MUL\". And computers are designed to do all the boring legwork, that's their entire purpose, so why not get the computer to take the text \"MUL\" and output \"43\"? Congratulations, you just made an assembler. A program that takes the text instructions and converts them to machine code. The first one would have been written in \"machine code\" by someone. Tricky, but you only had to write the assembler and then everything got easier. You obviously don't sit and write all your programs in machine code once you have a working assembler. But even \"assembly language\" (the codebook language that has \"MUL\") is a bit tricky to program in. So you make the computer do the work again. Using assembly language, you make a program that takes more complex text, and converts it into assembly language for you. So it might take something like \"A = B \\* C\". And it works out that it has to get B and C from memory, run the MUL instruction on them, and put the result into some part of memory called A. That program that does that might be called a compiler. There is a programming language called C. Generally this is the first compiler that anyone writes for a new type of computer, because it's relatively easy to write a C compiler in assembly language, and relatively easy for a human to write a program in C. That C compiler takes your C code (which looks a lot like Java) and converts it to simply assembler or machine code. Now that you have a C compiler you find that you can compile most things! Parts of Java itself are written in C. So when you have an entirely new type of machine, someone (who knows the \"codebook\" well) writes an assembler for it. The next (or even the same!) person then finds or makes a C compiler that itself can be written in assembler (there are lots of them already, but sometimes we have to make new ones!). Then the person after that? They have a C compiler and a whole raft of operating systems, kernels, programming languages applications, etc. that are already written in C. Notice, though, that all it took was two programs - some way to get assembly language into the computer, and then some way to convert C code down to assembler. Those are probably the most difficult types of programs to write, and sometimes you have to write parts of them from scratch (e.g. if a chip has never been seen before and is different to everything that existed before), but the assembler you can literally write by hand, and the C compiler is just a case of tweaking an existing C compiler. And only those two programs are needed (a slight exaggeration, but once you have them, everything else can be compiled from C!) to get everything else working. Computers in the old days (e.g. Apollo missions, and home computers right into the 80's) used machine code only and often had machine code tutorials in their \"starter manuals\". One of the programs they often got you to write was an assembler! And then C and other languages came later. Nowadays nobody bothers because it's all done for you, but still someone, somewhere, sometimes has to write an assembler (or modify an existing one to work on a new chip) or a compiler. It's like having to learn the alphabet, then learning how to form that into words, then words into sentences, then sentences into paragraphs, then paragraphs into chapters, and so on. It all starts at the bottom. And I could probably teach someone who knew nothing about computers how to write a very basic program in machine code, and a basic assembler to help them, in a few days. It would take far longer to write a C compiler but you probably wouldn't need to. Even today, when starting on a new chip, the people at the chip manufacturers will do that part for you - and they often start with the machine code to write an assembler, then using that assembler to compile a \"miniature\" C compiler (e.g. tcc), then that mini-C compiler to compile a full compiler (e.g. gcc), and then give that to you in a download so that nobody ever has to do that part again and we can all just take C code and compile straight to the new chip without having to have anything to do with machine code or assembler."
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llhyvg | How do digital to analog conversions work? | Analog signals are waves, meaning they should have a near infinite amount of possible states, compared to a digital signal which can ONLY be a 1 or 0. I understand that some logic is required to properly perform a DAC, and conversely an ADC, but how does a 1 or 0 represent a real world position of a wave? A wave doesn't necessarily have to be constrained to a certain boundary, for a simple example a wave of water can go as high as the amount of water in the ocean will allow. A digital signal however can only ever be a 1 or a 0, and that 1 or 0 is delivered at a different time than the next 1 or 0. I understand that perhaps the wave is formed by a collection of say 8 bits, a 1 being say a step up, and a 0 being nothing, but wouldn't that make audio choppy and discontinuous? As the computer has to wait for the full 8 bits to arrive before outputting the analog signal? If I'm completely wrong about this please feel free to educate me my mind is confused. | Technology | explainlikeimfive | {
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"Let's start by analog to digital conversion. Let's imagine a speaker, that moves back and forward, and we want to digitally capture what's happening. There are two things that need to be decided beforehand: - How often will we measure the position of the speaker (we call this *sampling rate*) - How precise will the measure of the position will be (we call this *bit depth*) For CDs, the standard is 44,100 measures per second (sampling rate of 44,100 Hz), and 65,536 possible positions (a bit depth of 16, e.g. 2^16 values). Why a value as high as 44,100 measures per second? The [Nyquist-Shannon sampling theorem]( URL_0 ) says that reconstructing a _perfect_ wave is possible, with no discontinuities nor chopping, as long as the captured frequencies are half the sampling rate; in the CD case, that means sounds up to 22,050 Hz can be perfectly reconstructed (humans can't hear above 20,000 Hz, so we even have some wiggle room). The sole trade-off of analog-digital transformation is addition of some noise, caused by the non-infinite bit depth. At 16-bits, though, the level of noise is low enough to be a non-concern. So, we start recording. We store the first 16-bit value; could be `0110110010110101`, then the second, `1001011010001010`, then the next; we do this 44,100 times per second. On playback, the DAC reads 16 bits at a time, that gives position of speaker at time Tₒ; reads another 16 bits, gets position of speaker at time T₁, and so on. The DAC keeps a set of values, then applies the Nyquist-Shannon sampling theorem to recreate the analog sound wave. Without choppiness; without discontinuities. A recorded sine wave will not “look like” a staircase once digitized then converted to analog, it'll be smooth as baby skin. (Why no staircase? As the sampling rate is 44,100 Hz, the DAC _knows_ that the maximum frequency is 22,050 Hz; a “staircase-like” waveform is impossible when only using frequencies below 22,050 Hz) So your hunch is right, the DAC needs to wait for a bunch of bits before it starts outputting analog signal, but that process is *very* fast for hardware.",
"> I understand that perhaps the wave is formed by a collection of say 8 bits 8 bits can represent 256 different numbers. If we have a wave maximum and a wave minimum, we can have 256 different levels. 8 bits per \"sample,\" we can make a rough wave. [The result is something that looks like this.]( URL_0 ) We can use some other electronics to smoothen out its bumpiness but essentially that's it. > wouldn't that make audio choppy and discontinuous? As the computer has to wait for the full 8 bits to arrive before outputting the analog signal? The computer can send bits far faster than it needs to create the audio level.",
"> but wouldn't that make audio choppy and discontinuous? Nope, if you use enough bits per second of audio you can make clear audio. Think of it like the resolution of your monitor, but for audio waves, it used to be that you had pixelated (choppy) and low color range (low dynamic range for audio), but now that we can use more digital storage for both, new can have clear and near perfect audio and picture saved digitally."
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llmiwo | why are there cables at different speeds if they are all made of copper? | Technology | explainlikeimfive | {
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"When signals travel through copper they create a magnetic field that in turn and induce signals on other copper wires. The solution for this is to have the cables twist around so that both of the wires recieved the same amount of noise, this is a balanced cable. I a cat 5 cable the there is 4 pairs of wires, and they all have a different number of twists per meter, allowing fewer places where the twists will line up perfectly parallel to eachother. In cat 6 the ratios are better, and also there is a plastic seperator to stop the wires from sitting so close together. You could technically try to put higher speeds through cat 5, but cross talk would just cause the data to corrupt.",
"The “speed” of a copper cable on a short run (less than 50ft) isn’t particularly related to the speed of a signal that passes through. It’s more related to how many signals can be passed through per second without loss. If you add more individual lines in the cable or increase how many signals you send per second, then you increase the speed. But if there’s interference between the lines or if the receiving device can’t read the signals as fast as they’re being sent, then the signal you’ll receive will be garbled. In a physical example: if you’re trying to get 2000 cars from one side of a city to the other, increasing the top speed of the cars won’t help. Increasing the number of avenues and reducing the number of crashes (interferences) is the best way to do so."
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llmwvl | How Alan Turing’s machine, the Bombe, worked to decode the German enigma-encrypted messages | Technology | explainlikeimfive | {
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"The main components was a bunch of rotors that were wired like those in the enigma machines. The first one was powered by a motor, and each full rotation it would advance the next one by one position. That allowed them to check all possible rotor settings of the enigma in a relatively short time. The second component was some really clever wiring that could defeat the \"Steckerbrett\" (plug board) of the enigma. [It is by far]( URL_0 ) the most complicated part of the bombe, and explanations you'll find online are often incomplete or just way too math-y to be easy to understand. But the short version is: It uses 26-wire cables connected in a clever way to check all possible combinations (many millions) of the plug board at once. The bombe was set to stop when it found a combination that could turned a part of the encrypted message into what they guessed was the correct word. When they had a hit, they could check if the combination can translate the entire message using an actual replica of an enigma machine. So finding messages that could be harvested for this kind of guesswork was a really important part of the operation - they often used weather reports, which came in nice and early and always included the word \"Wetterbericht\" at the same location."
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llnrta | Why TV static is black and white? | I know TV static is just radio noise the TV antenna picks up with multiple sources, but why only black and white static? Why no colours even with a colour TV? Wouldn't the TV pick some noise that would give it some colour? I tried googling, but couldn't get a satisfactory answer or one that wasn't too technical. I hope you can help me! | Technology | explainlikeimfive | {
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"Tv started out as black and white. Later, color signals were added but they were added in a way to make the overall signal still compatible with black and white TVs. The color portion of the signal is controlled by a 3.5795Mhz frequency burst and the TV has to lock to this to produce a color picture. Static is random and won’t have the color burst signal in it for the TV to lock to and produce color and thus no color in the static.",
"Think the signal as a snake. The head contains the color information, then there are other information, then the tail contains information about other stuff like self correction (if any) and sounds. The snakes are coming one after another via the cable. Your tv checks each snake, analyze it and shows the information it extracted. Now for static consider scattered meatballs are coming instead of snakes."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
llom6s | why do some lightbulbs flicker on and off for a second when you turn them on? | Technology | explainlikeimfive | {
"a_id": [
"gnqx9bo"
],
"text": [
"Are you referring to the initial flickering and clacking of fluorescent tubes? That is because the gas inside needs to be ionized before it can glow, and ionization requires quite a bit of energy. So they build up energy slowly, then release it in a spike which ionizes some of the gas, rinse, repeat. Each of those energy spikes will cause a brief glow of the ionized gas. Only after most of the gas is ionized, the tubes' glow can be sustained with the small amount of energy supplied to them."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
llopbc | Unified Endpoint Management? | Technology | explainlikeimfive | {
"a_id": [
"gnqtm4f"
],
"text": [
"Basically, companies have to figure out strategies and tactics for managing all of the devices that handle their corporate data. Everything has tradeoffs. There are two main tactics - MDM and MAM - which decide whether IT owns and controls your entire mobile device or if they let you bring whatever you want and they just control the bits that are important to them. To actually implement the control requires tools that can interface these devices. This is where UAM and EMM come into play. While MDM and MAM are the tactics, UAM and EMM are the strategic systems that implement the MDM and MAM policies. UAM is designed to support MDM across multiple platforms - no longer should you require a tool for the Android phones and a tool for the iPhones and a tool for Windows 10 laptops and a tool for Linux systems, but instead there's one tool that allows control over all of those platforms. Likewise, EMM is the strategic platform goal of MAM where a single EMM platform controls and manages all of your enterprise applications and maintains security from that direction."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
llsq4x | Why are internet cookies called cookies? | Technology | explainlikeimfive | {
"a_id": [
"gnr8897",
"gnr7tmd",
"gnrbltg"
],
"text": [
"Cookie comes from Magic Cookie, which comes from Fortune Cookie. The idea of a cookie with a hidden message inside.",
"URL_0 > The term \"cookie\" was coined by web-browser programmer Lou Montulli. It was derived from the term \"magic cookie\", which is a packet of data a program receives and sends back unchanged, used by Unix programmers.[6][7]",
"Me thinking that it was supposed to be like cookie crumbs that fell off which leaves a mark that works as a footprint"
],
"score": [
50,
28,
14
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/HTTP_cookie#Origin_of_the_name"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
llw0uj | How do AC to USB wall warts work? | Technology | explainlikeimfive | {
"a_id": [
"gnrppge"
],
"text": [
"They take the 120VAC, run it through a rectifier to make it about 180VDC. Then take the DC and switch it on and off with some transistors through a flyback transformer to transform it from somewhere around 180VDV to 5V. Bam, USB power. More complicated ones may be able to change the output voltage to allow for fast charging. Usually there will be some other misc features like short circuit detection and current limiting and similar. They can made a lot smaller that the wall warts of old because the high switching frequency 100kHz or more let's you use smaller transformers than the old ones that just let a transformer run off 60Hz."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
llz0jr | How come rotary phones came before phones with buttons? Isn't it much simpler to use buttons? | I don't really know how phones work(ed), nor how the dialing of a number "called" a different machine, but why did it make more sense to use rotary phones instead of buttons right away? What in the whole process, made it suitable for rotary phones? | Technology | explainlikeimfive | {
"a_id": [
"gns6luo",
"gns6qsh",
"gns6v79"
],
"text": [
"That was all before my time, but we covered it in electronics class. If im remembering right. The simplest way to explain it is that buttons were digital, rotary was analog. Buttons on phones are called \"touch tone\" because they don't actually work by button press=1/no press=0, intead they communicate with operations entirely through the sonic tones created when pushing a button. That was the whole foundation for \"freaking\" AKA 70s/80s machine hacking done by whistling. Touch tone was more efficient as the amount of telephones per household increased. While rotary phones are all mechanical dealing with governors and gear systems that establish the connection more directly, which worked well in a time when not everyone had a phone.",
"At the time rotary phones were invented, electrical buttons (the kind used in todays TV remotes and handset phones) didn't exist. Those came around in the 1950s or so (from a quick Google), so back when the patent for rotary phones came out in the 1890s that *was* the simplest method. I don't know the full technical details, but it was based on the rotation of the dial....the further you rotated it, the more electrical pulses activated while it traveled back to its starting position. So activating the number 6, would send 6 pulses to the central office (switchboard)....this is how it knew you \"pressed\" 6. Do that enough times and you get a series of 1 to 9 pulses representing each number in the phone number you were trying to dial.",
"Telephones were analog and not digital. There were no electronics at all at the time. The way that a phone number was dialed was to send a \"clicks\" along the phone wire. The clicks had to be timed in a certain way - so a rotary dial actually makes sense. The phone was designed not necessarily for the \"ease of use\" of the user but around the limitations of the day. The timing of the rotation of the dial was a necessary feature."
],
"score": [
10,
5,
4
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
lm0o25 | Why do drones/quadcopter have a long range, even though they have a small antenna while the router at home has a short range even though they both use a 2.4 GHz frequency | Recently i found out that some consumer drones can fly as far as 6 km with a small antenna. how can they achieve this? | Technology | explainlikeimfive | {
"a_id": [
"gnsgwnk",
"gnsifqk"
],
"text": [
"Your router's signal is getting soaked up by floors and walls and plumbing and electrical wires and carpeting and and and... You're flying the drone outside, with less to block the signal.",
"Antenna size actually plays little factor into range. Its sized to match the size of the wave, the higher the frequency the shorter the wave and thus the shorter the antenna. A problem with shortwaves is that they are also more easily reflected by objects, Wifi signals are often blocked by walls as much of the wave is reflected back the direction it came. In a house, this results in a shorter distance the signal can go. Outdoors they can travel further because nothing is blocking their path. Additionally, the controller my have a higher powered output than a wifi router in your house may have."
],
"score": [
13,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
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