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5smhk5 | Self-checkout machines have existed for at least a decade now. Why has the technology not improved at all over that span of time? | Technology | explainlikeimfive | {
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"Mind you, some grocery chains are heavily unionized and they have language in the contracts preserving jobs even with the rise in highly accurate automated check out systems. I'm willing to bet this is a major factor for some chains. Amazon GO is on the bleeding edge forefront obviously, but even Sam's Club is in the same sandbox with their scan as you shop app. You simply scan as you go with your smartphone and skip the checkout line completely. We are going to need a major overhaul in tech and social acceptance before fully automated grocery becomes the norm. We might even need universal basic income before it fully catches on, something I'm neither for nor against, but warily apprehensive.",
"The issue is that the people who make the purchasing decisions (C-level employees) never actually use the product. So the features that they find attractive (low price, sales presentations, a pretty case) have nothing to do with the actual product. At least with the cashier-operated POS, they have to care about efficiency since the cashier's time costs them money - but they don't pay customers, so screw 'em. Since the company that makes the self-checkouts knows that cutting costs, marketing, and a flashy package improve sales, but improving the actual product doesn't, it makes sense to spend your R & D money on the former. This is also why business-class software is almost universally crap.",
"Profit margins are also tiny in supermarkets. I'm not sure enhancing their POS systems to be more consumer friendly would be worth the hit to their bottom line to upgrade them every ten years.",
"I'll come from a different perspective: I use self-checkout machines all the time and I literally never have any of the issues you've described. So maybe this is more of a you-centric issue.",
"There are a range of them, some poor, some excellent. The likely culprit is that the really good ones are expensive. At my local Smith's (Kroger), they're complete crap. One block away at Walmart, they're extremely responsive and fast, allowing you in and out and I've never been buzzed by the security gates.",
"Of course, with the razor-thin margins grocery stores operate on their system upgrade paths are as slow as molasses. While there are scales designed to operate at high speeds (ie, stabilize very quickly once there's weight on them), they're expensive and thus not too popular. This is why your item will sometimes sit on the scale belt for several seconds while it decides what weight to report to the PC. There are also photoeyes on the belt that must trigger to tell the system you've put the item on there. If you put the item on the line too far down and miss these eyes (especially the first one right after the scanner), it throws everything off and the system will just keep telling you to 'put the item on the belt'. There are other sources of pain, like frost forming over the barcode on frozen items, a wrinkled bag making it hard to scan, etc. Source: I work with high-speed industrial material handling in e-commerce. Also, I grocery shop."
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5sngh1 | why do vacuum cleaners make so much noise? | Technology | explainlikeimfive | {
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"See URL_0 I've heard many times that they made quiet ones but they wouldn't sell because they didn't sound powerful."
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5sonm5 | Why does the peak volume vary so much from different sources on the internet: music, videos, etc? Also why can't your computer/speakers artificially amplify the peak level? | Technology | explainlikeimfive | {
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"It's actually more about average loudness than peak, but /u/swordgeek hit it - lack of standards. It used to be in some genres that musicians and/or engineers would push the loudness as high as possible into a peak limiter (therefore reducing dynamic range, which is a measure of peak to average loudness). This was done in order to stand out, for example, on the radio - when the radio is on in the background and your song comes on just a touch louder, it would catch people's attention. But then the [Loudness War]( URL_1 ) ensued, and that's because in music, film, spoken word, ...everything is pretty much left up to the mastering engineer (and artist, producer, etc) as to final loudness. However, a lot of services (iTunes, Spotify, YouTube, etc) are instituting their own loudness cap, such that if a video or song is louder than their prescribed loudness, their algorithm will detect that and turn it down. It's the beginning of the end of the Loudness Wars, since there's no point in absolutely crushing the life out of a mix that's just going to get turned down anyway. You might as well just have more dynamic range, which IMHO sounds better anyway. Read more [here]( URL_0 )."
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5spy6p | How come during the 1950's, they were called 'Atomic' bombs, but were then called 'Nuclear' at the start of the Cold War? | Technology | explainlikeimfive | {
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"They're all colloquial. \"Atomic bomb\" has historically referred to gun-type and implosion-type fission weapons first developed by the allies in the mid 1940s. In 1952, the United States introduced a new weapon which added a fusion reaction to the fission reaction in order to greatly improve energy output. These new weapons were of a fission-fusion-fission design and are properly called thermonuclear weapons. Colloquially these are called hydrogen bombs or H-bombs. Virtually all weapons deployed by the five major nuclear powers are thermonuclear weapons. \"Nuclear bomb\" is an umbrella term used to refer to all weapons that rely on fission reactions, fusion reactions, or some combination thereof in order to release energy. It recognises to some extent the fact that the public was greatly aware of the existence of these weapons but their details were shrouded in secrecy. Whereas a great deal of information about nuclear weapons can be found on the internet today, this was not the case during the cold war. It's also a politically convenient term because it is understood by everyone and has serious connotations. Politicians used (and often continue to use) it with wild abandon to spread FUD; Joe blow doesn't care what the CEP of a Russian MIRV is nor does he care about the yield of a W88. However, Joe very much cares that one does not land on his head and to do that he needs to be a good patriotic American rather than a commie bastard!",
"An atomic bomb works by splitting large atomic nuclei (fission) such as uranium or more usually plutonium, this releases quite a lot of energy. Hydrogen (Nuclear) bombs use an atomic bomb to ignite a nuclear fusion bomb - this is fusing hydrogen istopes together to form helium. This releases a lot more energy, especially as the neutrons released by the fusion part of the bomb makes the fission part more efficient.",
"The historical answer is that the term \"atomic bomb\" went back earlier than the weapons themselves. H.G. Wells talked about \"atomic bombs\" in his 1917 book, _The World Set Free_, and popularized the idea that you'd be getting weapons out of \"atomic energy.\" He didn't come up with the idea of \"atomic energy\" — he got everything he knew on that topic from Frederick Soddy's 1909 _The Interpretation of Radium_. Soddy's book predated Rutherford discovering the \"nucleus\" at the center of the atom, and thus used \"atomic\" exclusively. Anyway, when it came time to announce what kind of weapon the United States had dropped on Japan, the scientists said, \"you should call them nuclear bombs.\" The Army said, \"nobody is going to know what that word means, let's call them atomic bombs, everyone kind of knows what that is.\" The terminology stuck until the 1950s. The term \"nuclear\" started being used primarily in association with the phrase \"nuclear reactor\" (as opposed to the very antiquated \"atomic pile\"), and then was moved over into the weapons domain. By that time \"atomic bomb\" had been associated primarily with fission weapons but fusion weapons were also available, and \"nuclear\" was for whatever reason seen as a better way of bridging the two terms.",
"Atomic bombs refer specifically to fission bombs - which derive 100% of their explosive power from a fission reaction. Nuclear weapons refers to the whole category of weapons, including thermonuclear, neutron, and future hypothetical weapons.",
"/u/restricteddata can give you a better answer, but here’s my best shot: Members of the general public had heard of atoms but were not familiar with the terminology beyond that. Therefore, the bomb was explained in terms that they might understand: unleashing the power of the atom. It is more accurate to speak of splitting the atomic *nucleus*, and a few years into the Atomic Age it started to make sense to use the more accurate terminology."
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5sqo8e | How to video game developers "balance" different aspects of video games (e.g. The different fighters in fighting games, different races in strategy games, etc.) | Are there certain established theories of game balancing, or is it more trial and error? | Technology | explainlikeimfive | {
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"It's a really complicated topic. Games like Go have been around for a damned long time and are still working on how to properly balance the advantage of being the first person to be able to move. So part of it is trial and error. In more complicated games (especially fighting games, strategy games, anything strongly multiplayer) often developers shoot for some amount of *imbalance* but with the tools available to counter any strength. Think about a game like chess for a moment (which is, for the most part, perfectly balanced). What happens to the strategies, the gameplay? It's rote, it's calculated, it's just a matter of remembering and executing on those strategies rather than coming up with them. The same thing happened with Starcraft. The closer it got to perfect balance the more it became a matter of \"who can more perfectly execute the strategies everyone uses\" rather than \"who can think and play strategically.\" And so we started seeing people winning based on their quicker reflexes and clicking, not on the core engagement of strategy. Many developers now (especially for games like League of Legends, or Hearthstone, or Overwatch) are balanced for imbalance. Some characters *are* more powerful (but only marginally), which creates an incentive for players of the metagame (basically, people who play enough to want to figure out the best way to play/counter other play) to figure out how to beat it. There's a lot more to it in specific elements (balancing for skill, and why the \"noob tube\" in Call of Duty games is actually a great thing for everyone; or balancing using RNG) but generally speaking game developers try to come up with a power curve for their game and then not deviate too much from that. If a gun fires faster, it should have lower damage per shot, and vice-versa. If a gun is slightly off that curve (fires faster than normal for a gun doing its damage/does more damage for a gun firing at that rate) it creates interesting play around countering that; if a gun is *way* off the curve, it becomes an optimal strategy and boring. Look up Extra Credits, they've done a bunch of episodes on the topic. Short answer to your question: it's a little of both, but a lot of it really is more solidified than just trying stuff out.",
"As /u/Byde said. QA. They're assholes. They will fucking ruin your shit. If there's a 20 step process to make something marginally unfair, they will find it, and they will rub your face in it. Then laugh as you try to find some way to make it seem ok. Once you commit your changes to the new build, they will laugh again as they show you that you missed something, and it only take 28 hours of effort to completely break multiplayer. Once you've wiped away the blood, sweat, and tears and QA has to spend more than a week of dedicated effort to make things completely unfun for the new guy dropped into the pit, your game is ready for release.",
"Rarely do designers and programmers get balance even close to right early in development. Months of test plans by QA and good developers who can bury their ego and listen to the testers' bugs and suggestions create a well-balanced game."
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5ssdfd | if we say an atomic clock is wrong 1 second for every 1 000 000 years, have we actually a better way of measuring time? | Technology | explainlikeimfive | {
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"Yes, two atom clocks. You do not know which one is right but it gives you an indication of how accurate they are.",
"Not necessarily. But if you put ten atomic clocks in a room and come back and check them a year later, you can see if they have drifted apart, and use that to estimate their accuracy over longer periods of time.",
"1 sec/million years is orders of magnitude less accurate than the cesium clock in Boulder. It's something like 1 sec/15 billion years"
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5sss8k | Why do livestreams always have a small delay but group calls (on skype for example) don't | We can show our screen to everyone who's on the call (on skype) and it doesn't have a delay, then why do livestreams of games, for example, have that delay. Isn't it almost the same thing? | Technology | explainlikeimfive | {
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"Well, for starters, a video game stream is sending the data to sometimes *hundreds* of viewers (or more), whereas you're just sending data directly to your Skype contacts. In addition, the Skype video is likely nowhere near as high quality as the video game stream. Also, there often *is* a delay - a slight one - when you're using Skype. You just don't really notice it since it's maybe half a second tops. There are streaming sites out there that do have a much shorter delay than many of the mainstream streaming sites, too."
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5ssxo6 | How can companies say their energy saving light bulbs will last 20 years? | How do they test them as i imagine they haven't been left on for 20 years as that would be impractical and they weren't invented that long ago. e.g. LED bulbs. | Technology | explainlikeimfive | {
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"LED's have been around since the 1960's. they've been used in all kinds of industrial and commercial applications as instrument signal lights. using LED's as lighting instead of signaling has been around for a decade already in industrial and commercial. it's only recently in past few years that it's reached consumer. as for testing, it's not needed to leave them on for 20 years. you run thru an accelerated test for 30 days, then project the component wear results. if the projected time of failure is beyond 20 something years, that's good enough to say it'll be guaranteed for 20 years."
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5st26u | What are the differences between regular operating systems and real time operating systems, and why aren't all operating systems made to be the real time kind? | Technology | explainlikeimfive | {
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"The key feature of a real time OS is that if a request is made, it **will* complete in X milliseconds or less. Everything else is secondary to that. If the computer is controlling a self-driving car, it is going to read data from sensors several times a second, making adjustments each time. Those adjustments have to be made before the next reading comes in, an unexpected delay means the computer might react too slowly and cause an accident. > why aren't all operating systems made to be the real time kind? Because it is a very limiting requirement. Imagine a pizza place the guaranteed 30 minute delivery, or you get a million dollars. They would have to have dozens of delivery drivers sitting idle, just in case they got a whole much of orders at once. Compare that to a 30 minutes or it is free guarantee, where they can guess how many drivers they need, and occasionally give out a few free pizzas if they are wrong. A real time OS has to have enough resources available for the worse case scenario at every moment. A regular OS can use its resources more efficiently, because taking a few extra seconds to load your browser isn't going to cause a multi-car pile-up during rush hour.",
"/u/kouhoutek really nails it, real-time isn't the good thing it kinda sounds like, it's very limiting. But as a side note, many computer and OS designs let you have your cake and eat it too. For example, inside your cell phone there's the \"true\" OS, which isn't real time and uses a scheduler. And then on a *smaller separate computer* is the OS used for the LTE radio. This one IS real-time, and it shares a chunk of RAM with the main system. This way, you get the benefits of a multi-tasking OS with a scheduler, and the real-time benefits of never missing a radio signal.",
"The main benefit of a real-time operating system is providing a predictable amount of time that it will take to perform a particular task. A regular OS utilizes a buffer to allow dozens or hundreds of processes to run simultaneously but the end result is that the results of how long it takes to process the task isn't consistent. A processor can only process so much no matter the operating system, so it's not real-time in the sense that everything you want to happen just happens when you want it to. Generally they're only used in cases where there is a very high value in having predictable results, such as aerospace controls, and various industrial uses."
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5stzu1 | When burning a CD, does a 4x vs a 1x write speed change the quality of the end product? Is there anything different about a 4x vs any other speed other than, speed? | Technology | explainlikeimfive | {
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"I always thought this harkened back to the old days of CD burning, where buffer underruns occurred frequently. A buffer was created for the data being burned, and if the buffer emptied before the burning process is complete, it would fail. Burning at a slower speed (1x) meant you didn't empty the buffer and cause problems. However if your PC could handle it, you could attempt to burn at faster speeds (4x).",
"The crystalline surface of the CD will turn opaque when hit by the laser at the right power and frequency. That's what makes the 0's and 1's that would be later interpreted as digital data. Depending on the quality and materials used in the CD, the period of time that the laser has to be applied on a fixed spot varies. When each spot requires less exposure to the laser beam, less time would be needed to burn them, thus increasing the average burning speed. It is wrong to assume that slower burns provide better results. Actually, good quality CDs and DVDs *require* more speed (less beam exposure) otherwise the media would get damaged. Ideally the media should be burned at the manufacturer's recommended speed. No more, no less.",
"I worked at a mastering studio for a while where we produced pre-master CD's for mass duplication (this is a step below the \"glass master\" disk) and we always burned them at 1x. The writing mechanism has digital error correction which is applied to the data stream being burned. The faster you send/burn data, the more errors are being processed and corrected midstream. A slower burning speed supposedly cut down on the amount of errors being transmitted and corrected, resulting in higher data fidelity and less digital \"noise,\" dithering, and/or artifacts (noise being \"error corrected data\" not actual audible sound) EDIT: just want add that this was strictly for master quality disks that would be used to reprint large volumes. when it comes to making consumer quality copies or something for your personal consumption, the difference is negligible and undetectable.",
"My car radio can read 4x written CDs but not 16x written ones, so there's definitely a difference in the quality. Slower = fewer write errors, faster = more errors. Normally you shouldn't notice a difference though."
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5suj10 | Power usage by smartphones is progressively growing, but battery capacity stays relatively same. Why? | To clarify the question: we've seen impressive changes in their processing power, display size and resolution. However, there's little to no development of battery cell capacity. Why is that? *Edit*: Thanks everyone for the answers! | Technology | explainlikeimfive | {
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"Circuits in the phone follow Moore's Law (transistors double every ~18 months). The more transistors a phone has, the more power it uses. Moore's law says that number keeps increasing at an exponential rate. Even with good efficiency technology, that means power usage grows very fast. Battery technology is a more linear scale for many reasons. Most have to do with the difficulty of material technology and energy storage. We haven't yet discovered a set of technology that allows batteries to increase at the same rate as transistors. One thing to note in your statement though is that battery tech isn't staying relatively the same. It's actually improved quite a bit over the last few decades, and especially with the discovery of Lithium Ion technology. It just hasn't kept pace with the power that a computer could draw if it wanted to.",
"Smartphone power consumption isn't really increasing by that much. Newer processors actually have less power consumption despite being more powerful. When new processors come out they can can increase efficiency by shrinking the size of the transistors. (upcoming processors are using the 10nm process, which means the transports have 10nm wide gates) They can also increase efficiency by adding specialized hardware like video decoders and low power background processors. Screen technology is trickier, increased resolution does increase power consumption. But they are also moving to more efficient screen technologies like OLED (additive display, each pixel lights itself) instead of LCD (subtractive display, white backlight and filter to let some colors through). Also, software makes a huge difference. A well optimized device like the Pixel or iPhone will yield much better battery life than phone running on bloated crapware. About more energy dense batteries, how responsible is it to add more chemical energy to a device that already bursts into flames far too often?",
"For smartphones, power is king. People will buy phones because they run fast, because they can play high def videos, etc. So a huge amount of research and development goes into smaller, stronger components to give a device lots of power. And of course, plenty of development goes into other power-using components - screens, sound, etc. But as for battery.... people don't really go nuts for battery life. For a lot of people it's a consideration, but for many, it's pretty secondary. People don't go into a shop asking for the longest-lived phone, they go in looking for the most powerful phone, the highest-def display, etc. So battery consideration is a little lower on the list for most developers - it wouldn't hurt them as much to put a weaker battery in compared to marketing a lower-resolution screen with better battery life, for example. And on top of that, battery capacity is harder to improve than the other components - we're getting really good at making smaller electronics, but batteries are a chemical thing, so it's a different beast to make them small and still hold lots of power."
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5supxb | How people can hack your phone/computer with a USB drive? | Saw it on Mr. Robot, didn't know if it's movie magic or actually possible. | Technology | explainlikeimfive | {
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"It is technically possible. Heck, it may even be possible to hack your phone over the air. Hackers look for vulnerabilities in your software that allow them to install their own programs. They'll use these programs to gain root access and/or get your password. Vulnerabilities are typically code defects that occur in areas where we are dealing with outside data entering the device. Imagine a program that reassembles USB packets. As it gets each packet it copies it into memory somewhere. What if we could trick it into copying more data than it should? Imagine you have a bucket that can hold a gallon of water. If you pour more than a gallon in what happens? It spills right? This is called a buffer overflow in computer science terms, and it allows hackers to write data into places they shouldn't. Sometimes that data can be a program or a piece of code that allows them to install their own programs. It gets complicated quickly but the gist is \"If your program is handling outside data it can potentially be exploited\"",
"One approach depends on the fact that there's nothing to tell your computer that the USB device you plugged in is supposed to be a drive. There's nothing to stop the \"drive\" telling your computer that it's actually a keyboard and mouse. As soon as it detects power, it plays back a prepared sequence of key presses and mouse clicks to compromise your computer. I actually saw devices like that used in place of USB drives to distribute slides and supporting material at a conference. You'd naturally assume that it was just a drive containing the files, but what it actually did was appear as a keyboard, open the Run dialog (assuming that everyone uses Windows) and type the URL of their site to launch it in your browser.",
"The scene in Mr. Robot actually uses a real device^1 and there are a number of known vulnerabilities in USB implementation such as BadUSB^2. With the USB Rubber Ducky, it is possible to write a script in such a way that it will be able to 'detect' the OS and execute the corresponding exploit to gain access^3. There are many limitations though, and many of the known attack vectors are fixed, often it would require access to an unlocked machine. I believe it was possible though the BadUSB vulnerability to edit the code of the USB Controller (physically located on the motherboard), which would basically enable the attacker to do anything to any USB device plugged into it. 1. [USB Rubber Ducky]( URL_0 ) 2. [BadUSB]( URL_1 ) 3. [HAK5 Tutorial]( URL_2 )"
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5suyt4 | How does a Fitbit count your steps so accurately? | I recently got a fit bit and have loved playing around with it but it has kind of terrifying how accurate the step counting is. You can watch the number go up for every single step you take. Well, now I know that it isn't as accurate as I once thought. But, how does the Fitbit count your steps? | Technology | explainlikeimfive | {
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"~~It's actually under debate as to whether or not it can accurately track steps during heavy exercise. There's actually a class action lawsuit against Fitbit right now.~~ I was incorrect. The lawsuit is over the heart rate monitor not the step count.",
"It's not very accurate at all. If you've ever worn it to sleep, you'd notice. Sometimes I wake up with 50 extra steps. Or sometimes I get like 30 steps when putting on pants."
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5sv2zb | what exactly is 5G supposed to be and how is it different than 4G LTE? | Technology | explainlikeimfive | {
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"At the moment 5G is just a phrase and people do research on how to make things better then 4G. 5G is supposed to be better in any way then LTE. Faster, better energy efficiency, better range, use less bandwidth, etc. It's the next big thing in Communication and that's why there's lots of talk and research about it. But that's about it, still in developement and no facts yet. If there'd be a celebrity magazine for communication technology it would be filled with 5G and IoT at the moment. People love to read about those things and journalists really hype it up, so if you just add \"for 5G\" or \"for IoT\" to the end of your paper you'll have a lot more readers. Only the future will show how 5G will improve the techniques already in use by LTE. At the moment it looks to me like there aren't any big breakthroughs yet that will reinvent communications. So i'd say 5G will be just like LTE, but a little bit better. A lot more interesting to me is that they start to turn of 2G and or 3G to make space for 5G soon - that will have a rather big effect on lots of old phones and make them basically useless."
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5sxy9o | why the image of black and white television was so much sharper than the first several years of color television. | Technology | explainlikeimfive | {
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"Cathode ray tube TVs worked by having an electron gun draw each line of the image, one by one, around 30 times a second. The beam form the gun would strike a phosphor (think pixel), the strong the beam, the more brightly the phosphor glow. By adjusting the power of the beam at just the right times, a moving image was created. Color TVs use three electron guns, and each \"pixel\" consists of three phosphors. That made the pixels larger, and less sharp to begin with. Also, it could be difficult to keep the electron guns in adjustment. With a B & W TV, the whole image would shift over a pixel, you wouldn't notice that much. But with a color TV, two guns could be hitting adjacent (or worse) pixels when they should be aimed at the same one, which would also contribute to a less sharp picture."
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5sy12t | Why do some scientists warn about AI becoming self aware? | Technology | explainlikeimfive | {
"a_id": [
"ddiprwf",
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"text": [
"Because we don't know what it will be capable of or what it's intentions will be. If an AI becomes capable of improving itself it could become out of control and escalate it's abilities, and without morals it could go on as rampage destroying financial systems, traffic systems, power grid infrastructure, all kinds of things. We can understand the motives of a hacker or a terrorist but what an AI want to do could be beyond comprehension.",
"When people think about AI and the risks involved, they typically jump to the terminator or some other similar story. The problem with these examples is that they assume that a machine would think in a way similar to humans, but we know that they don't. Humans have an inherent self preservation instinct. Humans have their own wants or desires. Humans want to be free. A machine has none of these things unless we give it to them which would be sort of pointless in most cases. If you were developing an AI that kept track of the stock market and figured out when to buy and sell stocks, giving it a desire to be free of its human users would be pretty stupid. Now, that isn't to say that there aren't serious potential risks. This video has a thought experiment that illustrates what sort of problems we might run into with AI. The whole thing is worth watching, but the example starts at around 2:30 URL_0"
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5sy38v | Why do websites only display a small part of an article with a button "Read More" that displays the rest? | Technology | explainlikeimfive | {
"a_id": [
"ddiq8aa"
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"text": [
"the button click is recorded and it means the user is a human that expresses interest in the article content more than just the headline/first paragraph. this is a data point for creating a more accurate user profile's interests."
],
"score": [
8
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5sy5nk | Why does the iPhone require a passcode after restart if the fingerprint scanner is secure? | Technology | explainlikeimfive | {
"a_id": [
"ddiuqaj",
"ddiqq8a",
"ddj8hvy"
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"text": [
"As was made famous by the FBI/Apple confrontation from last year, recent iPhones do a pretty decent job of encrypting all content stored in the phone. The way the encryption works is that the *master key*—the big, 256-bit secret number that's required to decode the phone's contents—is never stored in the phone's permanent memory, but rather reconstructed when it's needed. Reconstructing the master key requires two pieces of information: * The phone's secret unique ID, stored in the processor when it is built; * The passcode selected by the user. The fingerprint scanner cannot be used for this, because it's an *inexact* scanner that doesn't produce the same result twice. It's like taking two photos of the same person—you can recognize that it's the same person in the two photos, but the photos won't be identical. But reconstructing the master key requires an exact match—something that's possible with a passcode but not with a fingerprint scanner. So the phone uses the fingerprint scanner to reduce the frequency at which you'd need to reenter your passcode. The phone can only use your fingerprint to let you in when the master key is available in temporary memory. Restarting the phone loses the content of the temporary memory, so you must reenter the passcode.",
"because the finger print scanner is not secure. It was created out of a need to be more secure without sacrificing usability. The finger print scanner stops your friend from being able to pick up and go through your phone, but it will not stop a determined actor from gaining access as your fingerprints are everywhere (including on the phone that they unlock). The thought behind the passcode on restart is to verify that you are the owner of the phone and that while it is turned on you will provide the necessary security.",
"Because you need a warrant for the password, and cops can scan your finger onto your phone as legally as they can your finger onto a finger print card. TLDR: turn off your iPhone if ever arrested. Edit: in the US anyway."
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5syxuz | Playstation/Xbox CD's copy protection, how does it work? | How does playstation or xbox games on cd's copy protection work? I mean I know you can't put disc into optical drive on your PC and clone it to blank blu-ray disc, I mean it will work but disc wont be recognized by console (Not sure if this changed but back when PS1 was a thing I tried it and it didn't work). So how does copy protection work? I mean if software like Nero clones data on disc identically onto blank disc, how can console see it's cloned? | Technology | explainlikeimfive | {
"a_id": [
"ddiz7tf"
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"text": [
"One method of optical media copy protection relies on the fact that legit media is pressed on specialized factories while pirated media is burned with home devices. When you burn an optical media you cannot control topologically where each piece of data will be located. Also, you cannot introduce intentional flaws and unconventional ways to write data. However, the common optical reader is able to pinpoint the physical location of each piece of data (sectors/clusters) and/or malformations. To check if the media is legit, it's only a matter to analyze how the data and reading errors are physically distributed through the media. Pressed media will *always* have exact the same configuration. In the other hand, to override the DRM validation, the game data should be written alongside a table containing where each sector was supposed to be located by describing the general topology and characteristics of the media. A tampered media reader would read this table, report as legit information and lure the console into believing that it is indeed an original disc."
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3
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5syzqz | Why do all sci-fi space helmets now have ambient lights on the inside? | Technology | explainlikeimfive | {
"a_id": [
"ddiwm9m",
"ddiwyai"
],
"text": [
"It's most likely just for cinematography's sake, it keeps the actors/actresses photogenic and easy to visually identify. It would unlikely ever be practical for the same reasons driving with your interior lights on is not practical.",
"A dark mask expresses very little emotion, which is why a bad guy will generally have no light. If you're paying, let's say, Chris Hemsworth as your helmet wearing hero you're damn well going to show his face and get those tickets sold through a little ambient light. Kind of the same reason a dark room is sometimes showed as a blue ambient light because a fully dark room serves little purpise unless there's a jump scare coming."
],
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|
5szw31 | how it is ensured website domain names are unique when there are hundreds of hosting services | Technology | explainlikeimfive | {
"a_id": [
"ddj27x2",
"ddj2855"
],
"text": [
"Hosting does not equal the management and sales of domain names. A host is a service that offers you webspace (i.e. the storage of your files that is accessible via the internet), basically the host is a company that builds and/or sells the house the homepage \"lives\" in. The domain is the \"address\" however and that will be centrally managed. Companies that offer you to \"buy\" a domain basically do either of two things: * They only manage the registration with the central registration for you, acting like somebody who files paperwork for your newly build home or * They sell you an already existing domain, acting like a realtor.",
"They have people who keep track of this information at a place everyone has access to. It is called [internic]( URL_0 )."
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"https://www.internic.net/"
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|
5t0fax | How is so much internet data sent through undersea cables simultaneously? | From what I understand, the vast majority the internet is sent through these cables, but I dont understand how so much data from billions of people can be instantly transmitted through so few of them. Like if I send an email, for a brief moment of time, is the entire cable dedicated to transmitting my message? | Technology | explainlikeimfive | {
"a_id": [
"ddj7tdm",
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"text": [
"> if I send an email, for a brief moment of time, is the entire cable dedicated to transmitting my message What you're describing is called a *circuit switched network*. That's how the telephone network used to work, and the telegraph network before that. Basically when you had a telephone call between two houses, switches in the telephone company building would connect a physical wire all the way from the sender to the receiver, for the duration of the call. Nowadays almost everything's a digital *packet switched network*, meaning digital data is broken up into relatively small packets [1]. Stations on a packet-switched network use *store-and-forward*, basically they receive packets from one physical cable into a memory buffer, then transmit those packets on another cable whenever that transmitter becomes available. Each packet has coded source and destination addresses in its control information. The equipment has software and data which tells it how to use the address information to decide which cable should re-transmit which packets, with the main goal of moving data toward its destination [2]. A single transmitter only sends one thing at a time. Figure an email the length of this Reddit post might be about 6000 bytes including control information (as well as the 40 bytes per-packet overhead, there's mail headers to consider). Network transmission speeds are usually measured in bits per second. 10 gigabits per second equipment is widely available (and 1gbps equipment is almost universal in new wired network equipment). So figure a single fiber can transmit ten *billion* bits a second. So the four packets of your email message takes about 4.8 microseconds (4.8 millionths of a second) on a single 10gbps fiber. As other users have said, each cable has many fibers. So the secret is each fiber is very fast, each cable is a bundle of many fibers, and there are multiple cables. Again, because this is a packet switched network, the 4.8 microseconds of transmitter time isn't a contiguous block of time that is scheduled to you specifically. Rather, the final piece of networking equipment which is physically connected to the actual undersea cable queues packets as they arrive and then sends them out along the cable as the transmitter becomes available. [1] For an idea of the size, most modern networks are based on a standard called Ethernet, which limits each packet to a maximum size of 1500 bytes. About 40 bytes or so is control information used to handle routing, sequencing, integrity checking and flow control; the rest is user data. [2] There are other goals which may affect the routing policies a network operator will program into its networking equipment. These concerns include security, fairness to all users, helping the network operator make money, and legal / regulatory compliance.",
"Google's submarine cable can do 60Tbps, that's just one of those cables. As for whether the cables switch between jobs, no, they do simultaneous transfer, and then where they transfer it sorts it out, sends it someone, sorts it, and etc. until it reaches you."
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5t1gsu | Film grain even in modern movie blurays, is it purposeful or why cant it be cleaned out? | Technology | explainlikeimfive | {
"a_id": [
"ddjdwrb"
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"text": [
"Film grain is a product of the chemistry that makes film. It can be made smaller, but the smaller grains take more light to switch on (expose). That makes finer grain film \"slower\" and it's a tradeoff between lighting and grain size. To eliminate it would take very intense light, so that's not practical."
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|
5t1qe0 | Why are car batteries lead-acid monstrosities and not cutting edge 18650's cells? | Technology | explainlikeimfive | {
"a_id": [
"ddjg0uf"
],
"text": [
"The cost is way lower. Both initial cost, and also in service lifetime over endless recharge cycles."
],
"score": [
11
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|
5t1zf7 | Why won't companies like Whatsapp and Instagram enter the Ipad market? | I find it extremly difficult for me that these companies don't have an app. This leads to using other 3rd party apps with many crashes and bugs. | Technology | explainlikeimfive | {
"a_id": [
"ddji847"
],
"text": [
"They don't need to. Remember their goal is to capture users ? There are very few people with an ipad and not an iphone. There's no reason to build and support an ipad app for people who are already using your service."
],
"score": [
3
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5t3m5z | Why does desktop Windows 10 not support dynamic backgrounds when they are such a common feature in mobile OS? | Technology | explainlikeimfive | {
"a_id": [
"ddjvfdd"
],
"text": [
"it might have if it came out in the dark days of cursor packs and desktop buddies. fortunately the desktop world has matured a bit and doesnt regard such gimmicks as a priority anymore. hopefully the mobile world will catch up soon"
],
"score": [
13
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5t4cu6 | How do MRI's work? | Technology | explainlikeimfive | {
"a_id": [
"ddk2jpw",
"ddk8e1o",
"ddka6pa"
],
"text": [
"The machine uses a very powerful spinning magnet that aligns the nuclei of water (H20) atoms inside your body (Since most of it is water), it creates a magnetic field that causes the atoms to resonate, a phenomenon called nuclear magnetic resonance. The nuclei produce their own rotating magnetic fields which aligns the proton \"spins\" and the scanner detects it and uses it to create an image.",
"This is what I do for a living so let's see if I can give it a go. Basically the body part we are looking at is placed in or on a coil (commonly referred to as a camera). That body is then moved to the centre of the magnet (known as isocentre). All the hydrogen in your body is aligned with the direction of the magnet's (scanner's) magnetic poles. Keep in mind you have 2 parts Hydrogen in every molecule of water in your body (something we have a lot of). A radio frequency wave (RF) is applied to the area of interest (yes the same frequencies your car stereo picks up) and the coil measures the speed at which either the hydrogen recovers to being back to being in-line with the magnetic poles or the speed in which the hydrogen decays from it's position immediately after the RF pulse. Now that's a very basic version of how it works. The differences in measuring give different weightings of images (i.e. different tissue appearances. Infection may not show on one image type but will on another). Someone astute might point out that there is not water in your lungs (or shouldn't be at least). Which is true! Lungs are basically the only area MRI can not image. That said, the hospital I work at recently started a new study seeing if we actually can at least measure lung capacity via MRI.",
"Hydrogen nuclei (protons - I will use the words proton and nuclei interchangeably) distribute themselves between two quantum spin energy states when placed in a static magnetic field, and only in a magnetic field. Hydrogen is a type of nucleus that is said to be magnetically susceptible (has nothing to do with a positive charge, which all nuclei have, but rather the existence of quantum spin states), and it is ubiquitous in body tissues, so a good choice. The lower of the two energy states is said to be aligned with the field, and the higher energy state opposed. More nuclei are in the ground state (aligned), because it's lower energy. The energy difference between the two states lies in the range of radio frequencies. Only a pulse with a frequency precisely matching that energy difference will cause spin state excitation, which means that a nucleus in the lower energy state is promoted to the higher energy state. A radiofrequency (RF) pulse, which comes from a transceiver consisting of a coil placed around the area being scanned, will excite a population of protons to the upper state, and this tips the bulk magnetization vector (average alignment of the magnetic spins of all the protons) out of the direction of the magnetic field. This creates a signal that is detectable by the RF coil, due to the spins of the nuclei within the magnetic field. One is detecting the average of all the spins, and the frequency emitted from the protons is the same as what was required to excite the protons to the higher energy spin state. One tries to achieve a duration of RF pulse that tips the spin vectors by 90 degrees, with respect to the magnetic field direction (and by extension, with the ground state orientation of the proton spin vectors); this gives the strongest signal. The rate of decay of the signal, from excited state to ground state, which is the basis for the imaging, is determined by a number of factors, but suffice it to say that hydrogen nuclei on molecules in various kinds of tissues have different decay (aka relaxation) rates. The RF pulse sequences chosen are designed to exploit those differences. You can imagine that if you have two kinds of tissues next to each other, and you want to be able to distinguish them from each other on the image, you might sample the RF pulses from their spins at a point in time after the excitation pulse that the protons in one tissue have relaxed completely, and the others have not, so that the latter shows a brighter signal. It's more complicated than that, but you get the general idea. One problem is that the detector does not know where the RF pulses are coming from, in terms of 3D localization from the area being scanned. Magnetic field gradients are used to create spatial resolution. There is a high-powered supercooled permanent magnet, usually 1.5 Tesla in strength, and then electromagnets that are tuned to produce a field gradient through the area being scanned. Stronger fields create a greater energy difference between the two proton spin states and therefore require a higher frequency RF pulse for spin state transition, and they also emit a higher frequency after excitation. So the RF pulse is broadband, exciting all protons, and the computer is able to parse out the various frequencies emitted. Since you know the magnetic field gradient, you know where the pulses are coming from and can therefore construct an image. There are also gradients created by altering the phase of the RF pulses being emitted. You need gradients in all three coordinate axes to know where an RF signal is coming from, to give a proper 3D reconstruction. The images are formatted as 2D slices in various planes, and what the computer determines for image construction is the strength of the RF signal from each small volume element in the area being scanned; these are called voxels, the volume equivalent of a pixel. A higher strength RF signal, by convention, gives a brighter signal. You can do multiple different types of RF pulse sequences to make various kinds of tissues bright. One kind will make water bright, another fat. The reason you are in the scanner for so long is that the RF signal being detected is very weak and scarcely discernible from noise, so the area being scanned is pulsed repeatedly and the signals obtained after each pulse are summed, so that background noise falls away, leaving a good signal to use to create an image. The thumping noise in the scanner, I'm told, is from the electromagnets creating the field gradient with each pulse. Beware of explanations that say the scanner is detecting the bulk magnetization vector of the protons, as is the case in some texts, including radiology texts. I've seen some BS graphs depicting this. The detector is picking up RF pulses, not magnetization. I don't know if you can even measure such a tiny bulk magnetization vector from the protons inside a static 1.5T field. I suspect not. But that's a moot point anyway, as there is no magnetization detector on an MRI scanner. Sorry so long, but it's super complicated. A Nobel prize was awarded for this technology. I think it's cool. Source: I'm a sports medicine physician also with a PhD in Chemistry. TL;DR: quantum spin state excitation and decay in hydrogen nuclei."
],
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5t6fhb | Why are some imgur-links viewable on reddit itself and some aren't? | Technology | explainlikeimfive | {
"a_id": [
"ddkhjx0"
],
"text": [
"Depends on what you use to embed the picture. Also sole users tend to post the imgur URL ( URL_0 ) instead of what they should post which is the picture URL ( URL_1 )."
],
"score": [
9
],
"text_urls": [
[
"www.imgur.com/example",
"i.imgur.com/example.png"
]
]
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|
5t8zrc | Why has every washing machine I've used taken 10+ minutes longer than the timer said it would take? | Technology | explainlikeimfive | {
"a_id": [
"ddl3tve"
],
"text": [
"Modern washing machines have sensors that judge the weight and sometimes the amount of dirt in the water. They don't judge these until it starts operating, and they may or may not update the time after the initial prediction. In addition, they may be judging the temperature of the washwater and spending time heating it. This won't get factored into the time. Finally, front loaders have programming to deal with balancing the load for the spin cycle. It may start spinning, get up to half the desired speed, detect an imbalance, stop, agitate a bit to stir up the fabrics, and then try again. This can add a fair bit of time to the wash that couldn't have been predicted in advance."
],
"score": [
4
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|
5t9cza | Net Neutrality and its opposition | Technology | explainlikeimfive | {
"a_id": [
"ddl40nh",
"ddl5nn7"
],
"text": [
"That's not Net Neutrality. Net Neutrality is treating all internet traffic equally. Here's an example: Comcast owns NBC and has a stake in Hulu. Comcast specifically makes your Netflix connection worse and gives priority to Hulu. This is Comcast specifically giving one source of traffic preference over another. Throttling your entire connection is a different thing.",
"Unless you're Netflix or FoxNews, no rules are being broken here. The idea behind Net Neutrality is that we (as citizens of the U.S.) have equal access to all information on the internet. So, what does that mean? That means when we go to URL_1 or URL_0 or URL_2 , we can get access to each site equally as efficient as the next site. Companies wanted their customers (i.e. Netflix, Wikipedia, FoxNews) to pay a premium so their customers (i.e. you and me) could access their sites more efficiently than other sites. So, mom-and-pop news sites or sites that did not want to pay the premium were not as efficient. So, how is this \"not fair?\" Well, imagine a world where all the \"rich\" sites paid that premium. They could spout off political opinions and what-not and be a lot more influential. By creating a \"fair\" internet for everyone, we allow everyone to create content and make it efficiently available to everyone else. It has nothing to do with a citizen of the U.S. trying to access the internet in the middle of the night from his laptop in his apartment. edit: Also, opposition. Some people believe in the free market. That if you can afford a premium and people will pay for it, so be it."
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"netflix.com",
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5t9p37 | How Does Emulation Work? | Specifically: Why does it take so much more power to emulate a machine that has significantly less capabilities than the machine you're emulating it on? | Technology | explainlikeimfive | {
"a_id": [
"ddlav7p"
],
"text": [
"Software developer here, Emulation isn't a 1:1 translation from one CPU instruction set to another, you also have to replicate missing hardware instructions, their side effects, and most importantly, their lockstep timing. The side effects and timing are the hardest part. You can write code that emulates the logic gates, and then you only have to perform a little calculus to time the clock ticks of the original system, but emulating the actual physical circuitry in this manner takes a heavy amount of computation time, and you'll still need certain software functions in your emulator to mimic particular behaviors that don't exist purely in the logic of it's gates, like cross talk, some errors, and any analog components. There can even be side effects as a consequence of its physical construction. You cam mimic this in something like Spice, as an electrical engineer would do, and you can even program and simulate in it, but that's a full featured analog circuit simulation package - if you want to run that in realtime, you'll need a massively powerful computer. The typical thing to do is try to take advantage of the host hardware as much as possible, but that complicates matters as some steps will compute faster, some slower, and you have to synchronize all that, while trying to take advantage of the time left from the faster instructions. And if you're writing an emulator for a fixed set of inputs, like an NES emulator for the number of ROMs out there, then you can take advantage of that and write code specific for that ROM to ensure faithful reproduction, possibly without actually executing those ROM instructions or running through the emulated hardware, just some sort of short circuit function."
],
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5t9sxv | How would abolishing net neutrality influence people outside the US? | Technology | explainlikeimfive | {
"a_id": [
"ddl9dru"
],
"text": [
"Indirectly. There wouldn't be a difference up front because your ISPs are regulated by your own country's laws. But let's say Comcast decides to extort Netflix to pay millions of dollars or have their data throttled. Netflix has to recoup those losses from their customers, and so they might decide to hike the price on subscribers even outside the US. But that would require businesses to be selfish dicks, which we all know businesses never are. Right?"
],
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5tag6y | Pros and cons of solid state vs regular hard drive | Technology | explainlikeimfive | {
"a_id": [
"ddlci4a",
"ddleyw8",
"ddldhxx"
],
"text": [
"Pros for ssd's: -Smaller form factors available -Significantly faster read/write speeds -Very low thermal output -No vibrations -Substantially less degredation in speed over time Cons for ssd's: -Higher price Sorry for formatting, am on mobile.",
"A big one for mobile users: SSD is much less susceptible to damage by shock. Imagine your phone with a mechanical drive in it.",
"Similar to what u/hamzakria said but with formatting: SSDs: Much faster read/write speeds, longer product lifetime, smaller form factor, lower power usage, lower thermal output. HDDs: Much cheaper, higher availability, larger capacities."
],
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|
5tapu3 | why is it hard to diffuse a bomb? | Technology | explainlikeimfive | {
"a_id": [
"ddleifn",
"ddlehyj"
],
"text": [
"Because bombmakers don't want you to diffuse their bombs, generally speaking. So they will create paths where interruptions cause detonations, for instance, so that by yanking out all the wires you set off the trigger.",
"It's not that easy to defuse a bomb because terrorists could always set it up to basically blow up when the detonator stops receing an electrical current."
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5taqim | Why traditional hard drives never come in normal boxes and do not have backplate but just exposed board ? | Like seriously. I just got new hdd and it is sold just as hdd I got 20 years ago. In ESD shield wrap. No box. And they still have that fragile exposed board on the downside | Technology | explainlikeimfive | {
"a_id": [
"ddleydg"
],
"text": [
"That's OEM packaging, if you buy them in bulk, the come in a large box with foam slots in it. If you spend a bit more money, you can get retail packaging with a box and padding and cables and a manual. As for the exposed board, there is no reason to protect it. They are mounted inside cases with a bunch of other exposed boards."
],
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17
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5taus9 | How do USB/HDMI/DisplayPort keep getting faster? | Are they making new discoveries? If so what are they? Or are they simply making thicker cables? Eg. HDMI 2.0 -- > HDMI 2.1 went from 18Gbit/s to 48Gbit/s USB 3.0 -- > USB 3.1 went from 5Gbit/s to 10Gbit/s DisplayPort 1.2 -- > 1.3 went from 17.28 Gbit/s to 32.4Gbit/s This was last look at [5 years ago]( URL_0 ) with speeds doubling again do those answers hold up? | Technology | explainlikeimfive | {
"a_id": [
"ddlidkd"
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"text": [
"Improvements in various things. For example in HDMI the speed increase is associated with a higher clock rate. Much like faster processors increased in Mhz, and into Ghz. HDMI Max Clock frequency to Data throughput - HDMI 1.0 - 1.2: 165mhz = 4.95Gbps - HDMI 1.3 - 1.4: 300mhz = 10.2Gbps - HDMI 2.0: 600mhz = 18Gbps - HDMI 2.1: ?? Spec not out to public or vendors yet, [here is some speculation though]( URL_0 ). This increase in clock speed is kind of like increasing the speed limit on the road. If the speed limit goes up from 25mph to 50mph, twice as many cars can go down that road. There are various reasons that increasing the frequency of the signal is difficult, and just gets harder the higher the frequency gets. Sometimes bandwidth increases come from adding pins/wires. This is like adding another set of lanes to that 25mph road. More lanes, more cars."
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5tbd9w | After years and years of pirating, why haven't they figured out a way to duplicate console game CDs in such a way the console can play them? | Technology | explainlikeimfive | {
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"Several reasons First the basics, Each console has a developer signing key, that key is used to encrypt and mark the software you master to CD to make sure that even if you managed to copy it, it will not run becuase the copy is not signed with a valid key from the authorizing authority being the console manufacturer. That encryption is VERY hard to crack and in the last 3 console generations people have resorted to actually modifying the console to execute unsigned software by changing the OS or in some cases even flashing the CD/DVD drive so it reports all discs as valid. Another issue is the duplication equipment, home CD, DVD and BR burners only burn the normal data tracks on a disc, while when you manufacture the disc on a factory from a master its stamped from a mold. This allows you to add extra tracks and features which can not be duplicated by a home burner, and the cost of setting up a Blueray duplication system based on mastering an original and stamping it would be prohibitive for pirates."
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5td30u | How do cryptocurrencies work? | I have been googling around for the past hour and I still can't really get a good idea of what cryptocurrencies are. How do alt-coins work? Why are AMD GPUs better for mining? What are the best cryptocurrencies to mine? etc. | Technology | explainlikeimfive | {
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"In a normal banking system you have central banks that keep track of all transactions between all bank accounts in a huge ledger. By summing up all the transactions related to a bank account you can get the current balance. So when a new transaction comes in the bank will check the transaction against the current balance and either approve or reject the transaction. If two transactions come at the same time the bank will handle them one at a time and might reject the second one if the first used up the remaining balance. Cryptocurrency is a decentralized system so you do not have a central bank. Instead the official ledger is public to everyone and everyone can validate it. However you do have a problem in that two transactions might be in conflict. You need someone to decide what transactions is valid and official. But instead of a central source which might become corrupted they use a cryptographic proof of work system. The \"miners\" do a lot of heavy calculation and might come up with a valid answer, if not they have to start all over again. The difficulty is determined by an algorithm so that someone finds a valid answer at regular intervals. Those who have gotten a valid answer gets to sign a new block in the block chain with new transactions for the ledger. They also get to add a bit extra money in the ledger that they usually give to themselves for their work. This reduces the potential for conflicts. There can be a bit of conflict if two people find a valid answer at the same time but then there is a majority rule. Of course the more heavy cryptographic calculations you can do the more likely it is for you to find a valid answer."
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5tdbhv | If I get youtube search results from 7 years ago and youtube never deletes videos, 30 years from now will my search results look exactly the same as they do now? | Technology | explainlikeimfive | {
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"text": [
"People do delete videos and accounts even if the company doesn't. In addition new videos are added all the time and the ranking changes due to how many views and the duration of each view, so \"less popular\" videos drop down the search list."
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5tdtu4 | How is music digitally stored AND played? | I've been wondering about this for quite some time now, but can anyone explain it without sounding overly complicated? There are no musical instruments inside a speaker, so how is it able to play recorded music? And relatedly, how is a recording instrument able to store sounds/music? | Technology | explainlikeimfive | {
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"Every single sound is just a combination of waves in the air. Instruments and the like are designed to create certain specific combinations, which is why (for example) a trumpet sounds like a trumpet: it vibrates the air in a attern that is (more or less) unique. Speakers are cool in that they are capable of producing any sound wave. They do this simply by vibrating a plate back and forth very carefully to create the exact same wave that was recorded. (This vibration is caused by an electric current creating a magnetic field that can push or pull the metal plate) Recording sounds works in very much the same way. If you play loud sounds at a speaker, the plate inside it will vibrate, and then produce a current which can be stored as data."
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5tfy2w | Why do subscription services like Hulu or Netflix take down titles that are in demand? | Technology | explainlikeimfive | {
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"text": [
"They license the titles with a certain time frame. After it expires, they can sign a new contract. Perhaps the licensor increase the price and Netflix doesn't want to pay for it.",
"Being in demand does not matter. They take down titles when their rights to stream them expire and they can no longer legally stream them.",
"Netflix licenses content from its owners for a certain price for a certain amount of time. Once that time is up, they need to renew the license. However, if the show is in demand, the content owners will want a higher price for it, and Netflix may not want to spend the extra money"
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5tgxjf | How do LEDs work? | Technology | explainlikeimfive | {
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"text": [
"Applying voltage to an LED makes electrons jump across a small gap between two crystals of different semiconducive materials. One with a higher energy state than the other. When they move from high to low, a photon is released. The frequency of this photon is determined by the semiconductors used, and the differences in their energy states. Smaller differences release shorter wavelength red light, while larger differences push the frequency towards the ultraviolet."
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5th9ix | Can you really find someones browsing history through Google? | So my friends have always told me that you can look up someones history through Google, if you just search their IP and shit. But I don't reallt believe that, I think it's totally BS. But is it really true? | Technology | explainlikeimfive | {
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"text": [
"You cannot find someone's browsing history through Google- the only way someone could see this would be if they had access to your computer or phone, or your ISP (the company that provides your internet) gave it away (they can see your Internet history). What you may be talking about is a website that gained some popularity recently (www.iknowwhat-- URL_0 ) which claims to be able to see what you have torrented based on your IP. I don't know if this has been verified to work, but even if it is legit this shouldn't affect most users (regular downloads won't be tracked, only torrents) Overall, there is nothing to worry about. You friends cannot just google your browsing history. EDIT: made the link invalid since I can't 100% guarantee it is safe, given the dodgy nature of the service it offers."
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5thg2s | How do they make Gorilla Glass stronger than regular glass? | Technology | explainlikeimfive | {
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"I don't think there's really such a thing as \"regular glass\" as you might think of it. Take steel for example. Steel is what's called an \"alloy\" which in it's own case is Iron mixed with some ratio of other elements, usually carbon. There is no standard type of steel. You mix in different elements in different ratios to get the type of steel you need. Stainless steel for example has chromium mixed into it and this is what prevents it from rusting. Glass too (and other materials) can be made this way, although technically not called an alloy I think (alloy is always metal). Typically the main component of glass is silicon dioxide (quartz) and mixed with other elements in certain ratios to give it the properties desired, although not all glass uses silicon dioxide to my knowledge. Other things can be done to it as well. Gorilla Glass has found some mixture of elements in this way that causes their glass to be extra strong compared to other glass mixtures.",
"They take regular glass and soak it in molten potassium salt. The sodium atoms in the glass come out, and the potassium atoms replace them. Potassium atoms are 30% bigger than sodium ones. Say you are playing Red Rover. A bunch of kids are lined up holding hands, and another kid tries to run between them. When the kid runs through, his goal isn't to split another kid in half. It's to run in between two kids and get them to let go of each others hands. If you replace 15 little kids with 10 big kids, then there are fewer places the running kid can split the line."
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5thkds | Who puts together programme schedules? And in the case of 24/7 channels, is it somebody's job to watch TV all night? | Who puts together programme schedules? And for channels that run 24/7 - is it somebody's job to sit there and keep an eye on the channel all night as nobody else would be around if it say, shut down or there was an error? | Technology | explainlikeimfive | {
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"There are major network executives who buy shows and then programming coordinators are usually the ones who are involved with scheduling. If there is a 24 hour station, you best believe at least one person (if not a few more) are at the station making sure, if there is a problem, that they can either delay the signal and fix the problem or just insert a new version (HDcam is the normal output version)."
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5thtnm | Why do advertisers allow their commercials to repeat over and over when aired on a steaming device? They must know it enrages their potential customers, right? | Is it so much to ask? I'm watching It's Always Sunny on my FX app on Apple TV and every god damn commercial is a delta spot with the stupid song from Snow White. It's driving me nuts! IT'S NOT ROCKET SCIENCE WHY ARE THEY DOING THIS TO US??? | Technology | explainlikeimfive | {
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"text": [
"Most of the time the point of commercials is not to actually sell you anything but to get their brand in mind. You may not like that they play commercials so much on your device but you do remember who's commercials are responsible don't you? Now how many other of that same type of business can you name? Chances are you can't name that many. There are well documented studies on the effect of brands and how it influences our purchasing decisions. In most cases people cannot remember more than 7 brands in a particular category, but if they do remember your brand they are far far more likely to seek out your brand and purchase your products. The commercial itself may be a minor annoyance but the brand recognition is far more valuable to the business. Edit: a word."
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5tj6ie | Why are there so many available opportunities to learn to code for free online? | It seems like everyone is on board with coding to be a universally free and easily accessed thing. How is the market not being saturated, and the coders not outraged the skill that makes them valuable is so easily obtainable. | Technology | explainlikeimfive | {
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"text": [
"You can learn the basics pretty easy, but getting good is hard and takes a lot of work. Most people aren't willing to put in the effort.",
"Learning the basics of programming in general, and becoming comfortable with some popular languages is not difficult. It's an excellent hobby to pick up and I would highly encourage everyone who even thinks that they might be interested in it to try it out. Mastering programming on the other hand requires an extreme amount of dedication, thousands of hours of studying, and a particular mindset that many people simply do not have. Nowhere in the scientific and technical universe is the phrase \"the devil is in the details\" more true than it is in computing. Those details are scarcely covered in brief online tutorials, they're found in thousand+ page reference books. A particular memory corruption problem may only be resolved by consulting the following: 1. A programming language's formal grammar, and 2. An operating system's ABI's specification, and 3. A compiler's architecture backend documentation, and 3. A microarchitecture's optimization guide A master computer engineer capable of reconciling all of those is worth a million self-taught python code monkeys. Out of those million self-taught python code monkeys, a handful might become respectable POSIX C gurus. However, without easily accessible online resources, those millions drop down to thousands and the field regresses to the underground days of the 1980s. Most veteran programmers, myself included, are more than happy to spend time helping the adventurous without any expectation of compensation. We do it because we've been there, we've spent hours tracing execution, we've spent days trying to hunt down seemingly inexplicable bugs, we've spent months working on projects just so that we can show them off to others, and we've spent years mastering our trade by learning from those who were willing to take the time to teach us.",
"Speaking as a coder, I simply don't see things that easy. Coding was a hobby. A fun set of puzzles to learn to understand. The fact that I make a living off it is a bonus. But I do make a decent living. Money isn't the only currency that matters. As I said, I'm getting plenty of that. The sense of helping, or of showing of my skills and knowledge is also valuable to me. I like sharing my knowledge. Other people like receiving my knowledge. The other aspect its that people will generally follow implicit societal rules from everyone else. I help others because it's the culture. I know full well that if I have a tricky problem in computer vision, or another specialised area, I can ask, and someone else will help me for exactly the same reason."
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5tjbeh | How do generative Artificial Neural Networks work? (AI that "imagines" images) | I have recently seen a [video]( URL_0 ) that blew my mind - ANN algorithm generates an image from text description. And then another algorithm increases it's resolution and makes it almost photorealistic. And then there was the whole deep art thing. Can you explain how these things work? I'm talking specifically about generative ANNs, not ANNs in general. | Technology | explainlikeimfive | {
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"It's very hard to explain a neural network in simple terms. But I'll try my best. I'll have to explain the basics of ANNs in general, though. A neural network works just like the neurons in our brain - actually, the neurons on our brain **are** a huge neural network. Artificial Neural Networks are the digital version of that. A **neuron** is a cell that receives multiple inputs from other cells, and based on those inputs, outputs something. These inputs have **weights** - some inputs affect the outcome more than others. The neuron basically takes the sum of all the values multiplicated by all the weights, and puts the result into a **windowing function** - a function that takes the value and spits out a number between 0 and 1, or -1 and 1. ANNs can also have multiple **layers** of neurons - that means the output of a neuron goes to the input of other neurons ahead of it, and so on. Now this is the part of a neural network that's hard to believe - you can train it to recognize or generate pretty much anything. Just like your brain can learn anything, the learning algorithms in an ANN can train it to do anything - but that requires an enormous amount of CPU time and data. By tweaking around the weights of all of the neurons using a very special algorithm, the ANN can learn to produce better and better results. Now obviously, an ANN works with just a bunch of numbers. That means you sometimes have to pre-process and post-process your data - by assigning names to certain numbers, for example. And now about generative ANNs: Just like we can learn how to paint photorealistic pictures if we train hard enough, a generative ANN can learn to generate images based on descriptions or other images. But the way we generate an image using an ANN is a bit weird - instead of putting parameters to generate an image, we put in an image (which can be white noise, for instance) and use the generated description to tweak the image pixels, so that the description generated by the ANN is closer and closer to the description we expect. And how do we train it? Simple, just put images into it and adjust the weights so that the description is correct."
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5tjjhv | How does ethernet over power work? | Those devices that plug into wall outlets and extend a LAN through the wall outlets. How exactly do they work? | Technology | explainlikeimfive | {
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"Normal ethernet works using several pairs of wires in a single cable. Each pair forms part of a circuit that can be used to send data via an electrical signal. Sending an ethernet signal through a single pair of power lines requires combining the signals from multiple pairs into a single signal with multiple channels, or using only a single pair of ethernet lines. This requires an adapter of some sort and you can generally expect poor performance compared to regular ethernet cables.",
"It's a [modem]( URL_0 ). It takes ethernet packets, and converts them into an analog signal, then transmits them over the power network in your house, and possibly to your neighbors. URL_1",
"Ethernet over Power literally works by sending over the data from the Ethernet network into your power lines using signal modulation. That may sound weird, but multiple signals can be transmitted over the same wire without interfering with each other. It's how Cable TV works. And the power wires in your house are reliable enough for that. The EOP signal is of a very high frequency, in the range of gigahertz, while the electricity is a 50Hz/60Hz signal, so any power application just ignores the EOP signal as it doesn't interfere with anything - even if it were to, a simple passive filter on the equipment's power supply easily gets rid of it, and that's basically commonplace in electronics design. The repeater, however, is able to tap into the high-frequency signal, demodulate it, and transmit the data over the wireless network. By the same principle it transmits the received data back to the router."
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5tjkg1 | Why do the pictures NASA releases to the public look like CGI? | I always notice that NASA releases photos and they almost always looks like CGI planets rather than real ones. Why is this? | Technology | explainlikeimfive | {
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"Part of it is because space lacks reflections. Really good CGI makes great effort to map all of the light sources and reflections in a scene. And I don't mean just mirrored reflections, but also the way light bounces off a wall and interacts with something like a couch. And there is also light from the adjacent room hitting that couch. So to make a realistic CGI couch, you have to model how different types of light hit the couch from dozens of angles. But in pictures of planets, there is usually only one light source: the Sun. So just like CGI modeling a couch with only one light source will look \"fake\", a real rock in space tends to look fake with only one light source. It is actually pretty easy to create a convincing asteroid in a 3d modeling program like Blender. But a realistic couch? That's hard.",
"A lot of NASA images are color enhanced because most of the light is outside our visual spectrum. There's also that if the images are from planets outside of the solar system then they are CGI artist impressions/speculations about what the planet might look like.",
"It's also worth noting that many space probes don't carry the cameras we use day to day. The cameras they carry are tuned for capturing particular types of light, which provides an image more useful to scientists studying the planet (just like how document copiers make really high contrast copies - useless for regular photos but makes text more readable). As a result the images we see are either the wrong colour (colour shifted or showing colours we can't normally see) or artificially enhanced to try and make them the colours we would see (which is a difficult process).",
"Film production designer here. Everyone else has already answered your question, but I thought I'd add one small bit of trivia, that is somewhat obvious but still manages to trick even me. As NASA photos are the primary and key detail reference source for all sci-fi films and animation, they end up being composites and merged with concept materials for every part sci-fi and fantasy technology. Anything from a Megatron's elbow joint to a space-age toaster may have been in some way shaped or modeled in part to resemble a physical piece of actual space tech. As we are now very used to seeing CGI massive robots, UFOs, Starfighter, and superheroes in space we make the assumption that the CGI is attempting to look as real as possible. This however is not true. Which is where the other answers in this sub step in. The way light lands in space is stranger than fact, and if animators aimed to match it perfectly it would not look \"right\" with our perception of what it should look like. So animators (and colourists) maintain a \"realer than real\" approach, by using three point lighting, fill lights, reflected ambience and haze to add atmosphere. These make the shots more visually stimulating, and also help intercut with incamera shots. In short by making it less real, we as an audience can relate on a natural/shallow/primal level to what we are seeing. This inturn leads to us seeing actual photos of real moon rocks, being hit by the actual sun (at a very difference distance to what we see on earth) as being ... well... wrong. Anyway, that's my 2 cents. Hope it was interesting.",
"[Example]( URL_0 ) [Images]( URL_1 ) of what OP is likely refering to.",
"The \"cameras\" NASA has often do not work like normal cameras, i.e. they might record infrared, UV, even x-ray or radio spectrum. This depends on what they want to measure. There are also cameras for the visible spectrum, but those are not that interesting from the physics point of view, so NASA usually puts in other measurements technologies into their probes. The raw data then is sent back home and scientifically analysed. In that process, the raw data is worked on, and people basically decide what is a) most useful for science or b) what looks the \"most\" close to what it would look in RL. And you also have c) how do you represent a infrared image in visible colours for displaying? If you have an gamma ray spectrum of a sun, how do you represent that as \"visible image\"? If you have a massive nebula that you only \"see\" because of absorbed infrared from a planet behind it, how do you visually represent that data? If we went there, we'd - with our eyes - see nothign at all. Those cases come with a lot of artistic freedom. So, in short, NASA imagines often look \"photoshopped\" because... they are. This does not take away their scientific accuracy."
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5tjskw | Why is the range of AM radio stations longer at night? | Technology | explainlikeimfive | {
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"During the day, there's an upper layer of the atmosphere called the \"Ionosphere D Layer\". The D layer is a very good absorber of low frequency signals (such as AM broadcast bands at 550Khz to 1600Khz). As the sun goes down, the D layer of the ionosphere dissipates and all that is left is the F-layer. The F-layer is much higher up in the sky and is much more reflective for signals in that AM frequency range. This is why most AM stations change patterns and/or reduce power at night. The increased propagation also increases the likelyhood of interference with co-channel users."
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5tksxt | Why can you "brick" phones so easily, but not computers? | Technology | explainlikeimfive | {
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"Bricking generally means making completely unusable at the hardware level. The reason that computers rarely get bricked is that we RARELY do any manipulation of the computer at the hardware level. To brick a computer, you would need to break the BIOS (Basic Input/Output System) which pretty much no one non-techy messes with. If you break windows, you can still reinstall windows. If you break the BIOS, you can hose things pretty quickly. The other aspect is that even with the BIOS, I can't think of ANYONE who would be messing around with the BIOS without using the official manufacturer's files. Most of the time you're messing with phones, you are doing so with custom firmware/ROM's, which means something made by someone other than the manufacturer. If you're flashing your BIOS, you're almost always going to be doing it with something provided (and quality controlled, tested, etc) by the company who made the product. So it comes down to two factors: 1) for computers, you generally don't tinker at such a deep level that you're going to risk bricking it 2) Even if you are messing at that level, you're not doing anything that is not officially approved of by the manufacturer. The final aspect is the fact that it's relatively easy to replace a computer (especially a desktop) part. If something in your phone breaks, 90% of us are just going to give up because it's so hard to replace. Most of the stuff that's likely to go bad is also easily replaced/substituted. I fried my sound card on one of my desktops a few months back, and for $10 I just plugged in a new sound card. If I killed the speaker on my phone, I'd say fuck it and just buy a new phone.",
"You actually can brick a computer if you manage to turn it off during a bios update for example. Android has something similiar to computers bios, called OEM bootloader. It is being run before the operating system, just like bios in computer. The thing is, if you want to replace the operating system in your computer, you do not need to replace or do anything at all with your bios. Bios by default allows you to boot from usb or cd/dvd and so you can judt install the OS freely. This is not true for android, most android phones are OEM locked, and their modloader often also disables ability to access recovery mode, which allows you to flash custom OS, just like booting in your computer. Here is the key part, you as an user, have by default full access to your computer as an administrator (you can install whatever program you want, do whatever you want with your pc, you can even overclock your processor), but for your phone you do not have administrator rights , so you are limited to the OS ans settings set to you by the company . To bypass this and gain full control of your phone, you need to do something called rooting a phone. Rooting can be dangerous as it most of the time takes replacing the bootloader. If you fail to replace the bootloader properly, you brick your phone, as it is unable to start even the loading process before OS. This is a hard brick. Soft brick is when the OS you flashed (installed) is broken and the bootloader can not load it, you can still just flash another.",
"PCs are built with openness in mind. Meaning on a PC you can install different OSs, boot from different media, install different hardware and so on. It's all under the users control and if you screw things up, you just boot from a USB stick or DVD and recover easily. PCs are meant to be tinkered with and handle accidents well. Even for accidents in the mids of a BIOS upgrade many mainboards have ways to recover from that. Phones, tablets and game consoles are the complete opposite, they are locked down so that the user has little to no control about what is going on. Meaning a lot of tinkering has to happen in areas that the manufacturer didn't intent to be tinkered with or actively tried to prevent tinkering in. This means the tinkerer is walking a minefield and any error might put the device into an unrecoverable state. All of this is not an accident, but by design. If manufacturers wanted to, they could make phones as easy to recover as a PC by letting the user boot from SDcard or access the internal flash storage via USB. Case in point, many bricked PSP could be recovered after people found out that booting from the memory card was possible via a modified battery. The feature was there all along, but not documented by Sony to prevent hacking. Another issue is that even if the device allows you to recover, you would still need the data to put on the device to recover it. On a PC you have Windows install discs, Linux distributions and all that readily available to reinstall on a blank device. Getting the OS image for your phone might not be that easy. To make things further more complicated, the ecosystem around those devices is not standardized and discoverable, which makes it hard to create software that works across different devices. A Linux distribution will work on essentially any PC, but you can't make a Linux distribution that will work as easily on every phone as all the hardware around ARM varies from manufacturer to manufacturer.",
"As others have mentioned you can brick a motherboard if you try hard enough. When I was a kid, I flashed a BIOS upgrade onto my dads machine, except I accidentally flashed the file for almost the same version (think XXXXX+ vs XXXXX Pro or similar) - and it totally let it flash, and upon rebooting, the machine was dead. So I panicked, because like, it's my dads PC right and he's not going to understand what I was trying to do, he's just going to be mad. And I can't afford to buy a device to reflash the chip, nor did I have any idea how to make one, at the time. But then I remembered my machine had the exact same motherboard, and took a look and, yay, the chip was removable. So I ask a bunch of random people on IRC if it would be sane/possible to boot my machine, get it all ready to flash the correct firmware, then while the machine is on, pull out the BIOS chip and replace it with the dead one, and flash it from the system that's already booted. This seemed to make sense to me, but they all told me it was stupid and would break the other one. (I've since found out that, obviously, I did not invent this idea, but hey I was really young, when you're young you came up with everything first) Desperate kids will do anything an adult tells them not too, though, so I did it anyway and it worked. Didn't get hit with a belt that day! : >",
"The TL;DR is that messing with your phone happens on a lower level than messing with your computer. For context, imagine if you suddenly had to start flashing a custom bios because the manufacturer made it so it could only run their flavor of Windows 10.",
"phones have good reasons to mess around with the hardware code - since they put in stupid things that prevent you from doing things that you want and that the device is capable of, and its pretty much a requirement to fiddle around with the OS computers there just isnt a good reason to. you dont need to do anything to the bios in order to install different OS versions and there are no real benefits that i can think of even as a techy. ive flashed a bios once and it was with software the company provided me. years of tech experience and it only required it once... but ive flashed every phone i had. i really dont think its that easy to brick a phone. ive never bricked one and every problem i ran into while flashing it was fixable. i think alot of the time its people just getting confused and throwing in the towel rather than them actually bricking it",
"we live in a consumerist world and that means companies wont work together any more than they have to in order to maintain market dominance. **Phones can be almost if not entirely \"in house\"** phones are designed to be \"good enough\" so that they can be produced as soon, volumed, and cheap as possible =the components are designed to be entirely dependant on each other with very few if any redundancies. **Computers are less \"in house\"** computers are typically made by multiple companies often that compete with each other[phones also but to a lower degree] or simply by people like you and me SO because of this in order to keep a product relevant PC parts are by nature designed to be more robust and reliable because the components are designed for a much wider compatibility = less dependant on specific archetectures. Also its simply alot easier to replace components in a PC than in a phone because a PC doesnt need to fit in your pocket. **tl;dr:** phones sacrifice redundancy for convenience, pcs do the opposite.",
"The real answer is that you *could* easily design a phone that was very easy to customize and very difficult to brick just like a computer. The reason this doesn't happen is that the cell network operators (who are the main customer of the phone manufacturers) don't want you customizing your phone. It is intentionally difficult to modify the phone. You must break through the manufacturer security to modify things. Cracking a device to do something it wasn't supposed to inherently comes with risk of breaking it. Computers are in a completely different market where customizability is important, especially to business and government customers. Expect computers for the consumer market to drift towards to difficult to customize end of the spectrum.",
"It really is fairly hard to brick a phone. You still have to make a stupid mistake. But Android phones have 3 partitions they can boot from (fastboot, recovery, and system). Mess up all 3 and you have a brick. Computers can boot from the CD/USB drive as well as internal, you the only way to brick it is to mess up the BIOS (that screen that flashes before Windows starts booting). Which normal users don't touch. The BIOS is what tells the computer where to look for something to boot, and as others have posted, it is possible to update the BIOS and if you turn it off or somehow try to use an incompatible motherboard's firmware, bad things can happen. But newer motherboards have a recovery BIOS too, so those would be really hard to brick.",
"There are only 2 ways a computer can be \"bricked\" : 1. The BIOS can be corrupted 2. A piece of hardware can fail, whether due to mechanical damage (you slipped with a screwdriver while tinkering) or failure due to wear out/manufacturing defect. Either way, the fix is the same. For a desktop computer, you just identify the component that broke, order a replacement, and pop it in. The only form of failure that can cause permanent inconvenience is when the hard drive fails and you don't have a backup. If you messed up the BIOS, worst case scenario you can just replace the motherboard. Some motherboards put the BIOS on a socketed chip you can replace. These days, many motherboards actually have at least 2 copies of the BIOS - some let you switch to the other copy of the BIOS via a jumper, or more commonly these days, there's a bios you cannot alter that will kick in if the main one fails to boot or if you push a recovery button shortly after power on.",
"Even if you \"brick\" a computer you only basically ruin the motherboard. The rest of your computer is perfectly fine, and all you would need to do is replace that component. Phones aren't repairable in that sense.",
"Many motherboards have dual BIOS. So even if you screw one up you can boot into the other. I can understand why Apple doesn't do the same as their all about iron fisted control over THEIR ecosystem but it does make you wonder why premium handsets on Android don't offer such a feature, whats Samsung et al interest in protecting Googles ecosystem?",
"How to brick your PC easy.. 1] Attempt to flash GPU with bad BIOS code, especially if its graphic card without backup BIOS [there are some that feature double BIOS, but dont worry its possible to brick them too]. Especially dangerous can be \"unlocking\" BIOS that gives either new functionality or tries to unlock unused parts of GPU. That can actually end really nasty way. 2] Any BIOS flash of motherboard can end same way, especially if it contains some unsafe tweaks or wrong default voltage. 2v into vCore = dead CPU. 3] Try to flash anything and get power shortage. Or just turn off PC. 4] Do unsafe badly cooled overclocking. Reality is that you can brick your PC [or parts of it] very easily, if you not careful in what you do. But it applies only to ppl trying OC or flashing stuff. Experienced people usually dont brick em and general public has no idea what I just wrote [so they safe too]. In some aspects its same, if you flash your cellphone wrong way it dies, if you do same with PC components, they might die too. If you do it in really bad way, you can kill more than just one component. IMHO, read everything you can before you try anything risky with cellphone or your PC. I think it usually helps. **TL:DR - You can brick PC same way as cellphones, just most people dont try same things with PC as they do with cellphones, cause they lack knowledge or will to attempt it.** *Side note: Why you would try to flash BIOS in PC? Well, BIOS upgrades for one. Unlocking full CPU power for another. For example some time ago, you could buy cheap Xeon CPU [Intel server processors] and with simple BIOS flash unlock option to overclock it as easily as mainstream [expensive] CPUs from Intel. Obviously not many knew that, which is reason why I still see those CPUs being very cheap in store.. :D*",
"You can wreck a motherboard pretty easily if you go fundamentally changing the BIOS. I had a BIOS update go bad once. It took about 5 minutes to go from a happy beep telling me that an update was ready to \"shit, that was a $500 mistake.\"",
"PC manufacturers don't try to use the BIOS to lock end users out of their machine's functionality.",
"It is actually fairly easy to brick a computer if you're trying to. On a software level it would be tough, but not impossible, you can mod BIOS or some hardware code if you intend to. One time me and a girl were building computers in a shed and I explained how the term 'bug' came from bugs literally getting into circuit boards and frying them. Just then a large mosquito-hawk landed on the exposed motherboard and it fried the board and that forced a hard shut down, bricking the computer for all time.",
"ELI5 ANSWER: For phones installing OS and other tweaks generally write data to flash chips (I THINK THEY ARE ROM) to open up the hardware more, that if corrupted can be very hardhard/IMPOSSIBLE to reprogram (bricked). For pcs hardware is very open and you can pretty much install what you want with no hardware reprogramming. (FIRST ELI5)"
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5tnxnd | Panasonics new "invisible tv", how is it transparent? | Technology | explainlikeimfive | {
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"[Their screen]( URL_0 ) is an array of very small LED lights (red, green, and blue ones) printed on a sheet of clear plastic (which is then placed behind the clear glass. When the shelf light behind the glass is turned off, it is black back there so the clear parts of the screen look black, and the lit parts are the colors you see. [See this video.]( URL_2 ) [An earlier version they showed]( URL_1 ) looks like it had the OLED screen with a black and white LCD screen right behind it. So the screen is transparent when the LEDs are off and the LCD at that position is also off, black when the LEDs are off and the LCD is on, and colors when the LEDs are on and the LCD is on. This is how they can have part of the screen clear to see the shelf contents and part black at the same time. Notice that the black isn't perfectly opaque, so you still see the shelf a little while the screen is on and moving."
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5to1ay | Why do phones have separate speakers for calls and media? | Technology | explainlikeimfive | {
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"Generally one speaker is designed to sound good at very low energy, very close up; the other is designed to put out many times that amount of power, and if it started playing in your ear, it could damage your hearing. So they mount it separately, facing the other way. it's also used for speakerphone."
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5to9o2 | How does mobile "Direct Deposit" work for checks? | Technology | explainlikeimfive | {
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"You take pictures, you enter amount, you send it in. They use a computer to analyze the check and the serial numbers to see if it's a true check, they also check the amount as well of course."
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5tphti | How do big companies/colleges maintain high internet speeds across hundreds of people's devices? | It was a random thought that occurred to me. I've heard about how connecting a ton of active devices to a home network can cause congestion (and slow it down?). I'm a university student and I am always able to have a fast internet connection even when there's hundreds of people in the same building as me using the network. | Technology | explainlikeimfive | {
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"Your building has lots and lots of access points all connected to many, many switches. Each switch is likely to be able to handle a Gbit of traffic *on each port* so for a 24 port switch that's a 24+ GBit back plane. Your college also has an industrial level internet connection. And if its a large research institution it likely is a node on Internet2 which is an all fiber network that connects lots of colleges and other institutions. When you data needs to get to one of those institutions, it gets automatically routed over the super fast fiber connection.",
"What /u/dodgeBallRocks said is correct. To add to it... Connecting too many devices to your home Internet is a bad excuse given by your cable provider. They have one 'pipe' to your entire neighborhood. Let's say you and your 19 neighbors pay for 25 up, 25 down. Your neighborhood pipe only carries 200 up, 200 down, even though it needs 500 up and down to serve the max your neighborhood is paying for. Everyone in the neighborhood tries to watch Netflix around 7pm, and all of you have buffering issues. Even though you pay for enough Internet, the neighborhood pipe can't carry all the data it needs. Your connection ends up competing with your neighbors', and no one gets good service. Fiber doesn't have this problem. Each house has its own 'pipe'. You're guaranteed to get the speeds you pay for, assuming your hardware in the house can process it.",
"all that has been said so far is accurate but just to add... industrial level internet connection is SO FAST. i mean... SO FAST. if you get 50mbps download speed at home, your doing alright for yourself. at work i get 400mbps. 400. FAST. and where i work is a small workplace. universities i can imagine would be able to go much faster."
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5tq8bo | What happens when a program is not closing when the "x" is being clicked and also when a program is closed due to "Force Quit" or "End Task" in the task manager? | Technology | explainlikeimfive | {
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"Clicking the \"X\" sends a signal to the program that tells it to gracefully stop what it's doing and shut down. This lets it properly save progress, close any open files, etc. Correct operation depends on the program responding; if it has crashed in certain ways this can't happen. Force Quit / End Task is slightly more violent. It terminates the process directly and leave it to the OS to clean up whatever junk it left behind."
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5tsb25 | why are computer viruses being created and spread? Do they have a function other than wrecking computer software? | Been wondering about this for a while. Are all viruses just product of douchebaggery? | Technology | explainlikeimfive | {
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"Some are just douchebaggery, some are in good fun (the hello world virus), some are for profit (ransomware), some are for spying and then you have the viruses that have a very explicit goal (like stuxnet). There probably are other types, but the basic premise is running a program on an infected machine with a specific purpose. What that purpose is depends entirely on the intentions of the creator. Take stuxnet for example. This was most likely the product of US-Israeli collaboration with the extremely specific purpose of shutting down certain parts of an Irani nuclear powerplant. Since that powerplant had closed circuit electronics (not connected to internet or other networks) the virus needed to be implemented manually. The way it worked was quite ingenious. It spread through the internet but only to other computers that were physically closer to its intended target. The goal was to eventually infect a usb-stick that would be connected to the closed circuit of the nuclear power plant, which it did after a 2 year journey on the internet. The damage it caused took 2 years to repair. Anyway, most viruses are written for some form of gain. Be that in personal information, monetary gain (through ransomware or by stealing credit card credentials) or political and/or geostrategic gain. But like I said, everything depends on what the creator of the virus intends.",
"Several reasons: Wrecking software just for the sake of it would be one. Also, give me money and I'll restore your software back. Gaining control of computer resources to make them work for your own interests would be another. Obtaining personal information such as log-in data to email or bank accounts is also very sought after.",
"Computer virus is a broad term. We call that any program that's capable of replicating itself for unscrupulous motivations. They certainly have other purposes, and the most harmful ones are those that *don't* wreck software. Viruses that want to spread as much as possible rely on the fact that its host is unaware of its existence. Therefore it's in the best interest of the author that the computer were it resides keeps working as good as before the infection. As far as I can remember viruses started as \"douchebaggery\". Long before the Internet they spread by hiding themselves on magnetic discs. Some did impair and eventually break the systems, while others just displayed funny messages and messed with your screen (e.g. Ping Pong). But it didn't take long, specially with the Internet, for viruses to be used as a form of lucrative venture. If they can replicate and reside silently on a host system, with administrative privileges, the constant online state of most computers enabled them to send private data back to their author without much effort."
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5tsh0l | When my smartphone's battery dies, I have to wait a few minutes to use it again when it's on charge. When my laptop's battery dies, it works right away when on charge. | Technology | explainlikeimfive | {
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"Lazy ELI5 but. Laptops are designed to draw power straight from the cable so they are still usable without a battery. A Mobile phone only draws power from the battery so it needs power before it can power the device.",
"> When my smartphone's battery dies, I have to wait a few minutes to use it again when it's on charge That's not the case for all phones. My phone (Nexus 5X) works on the charger right away even if my battery has been depleted dry. I guess some devices can switch their power source on the fly between battery and straight from the power cord."
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5tsoeo | How can encryption methods be open source? | I was reading about the signal protocol and saw it has a github page. Doesn't this mean anyone can figure out how the encryption works and break it? | Technology | explainlikeimfive | {
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"It is a generally accepted security precept that \"The enemy knows the system.\" That is, when you are designing an encryption algorithm (or any security measure) that you assume the enemy knows its design. You assume that, eventually, an adversary will get a hold of the algorithm and therefore A) you cannot rely on the secrecy of the algorithm for security; and B) your algorithm should be secure despite general awareness of it. The strength of encryption methods lies in the keys (and, for asymmetric methods, the inherent mathematical difficulty of reversing the encryption process). For example, the most secure encryption method, the One Time Pad (OTP) has an extremely simplistic algorithm. ALL of the security is invested in how the key is created, used, and kept secret.",
"> I was reading about the signal protocol and saw it has a github page. Doesn't this mean anyone can figure out how the encryption works and break it? As a general rule, you should never ever give ANY credence to encryption methods that are not open source and fully examinable by you. NSA and other parties have tried to weaken encryption measures precisely by creating partially closed source encryption methods which then would have weaknesses only they would know about, and only they could exploit. Which, even if you're totally cool with NSA breaking your encryption, would still mean that there is an exploit that may eventually get out because NSA messes up for example, and some Snowden type leak reveals how to decrypt all your supposedly secure data. Any encryption method consists of essentially two parts: There is method you use. This HAS to be public, everyone HAS to know exactly how it works. Then there is the key. This key is random number sequence, typically it's about 256 bits long, sometimes even 2048 bits long. That's computer talk, but basically 256 bits long key means, you choose any number between hundred billion trillion trillion trillion trillion trillion trillion, and trillion trillion trillion trillion trillion trillion. Or basically, number that's maybe 84 or 83 decimals long. The security comes from the fact that you need to know the exact number, every decimal of it, to encrypt or decrypt data. Guessing such a number, if you guessed trillion trillion trillion trillion trillion numbers every single nanosecond, would take roughly... Well, 31 million years to guess it right? Trillion trillion trillion trillion guesses every nanosecond is far more than anything we can currently do, and 31 million years is far longer than we can wait to decrypt something. Secure algorithm is such that you don't have any good shortcuts that are easier for decryption than trying trillion trillion trillion trillion trillion guesses every nanosecond for 31 million years. You don't know your algorithm is secure if you can't see it. A random 84 digit number could be 834,485,888,921,132,283,384,723,847,928,073,987,476,456,352,956,839,445,342,342,475,324,647,232,344,664,756,578,495,4,543,436,234.",
"What needs to be secret is the key (or set of keys), not the way in which the lock is built. If knowing how a lock is made can be enough to access without having the keys, it's a poor lock, no matter if its inner workings were known by legitimate access to the source code, or by reverse engineering. (EDIT: typo)",
"We all know how a mechanical door lock works, but that doesn't mean you can just break into any lock easily. It is still much easier if you have a key. For encryption it's kind of the same. Knowing the algorithm might give a small edge for whoever is trying to break it. Or not. Modern algorithms (e.g. AES) are actually *designed* to be completely open source and yet you'd be helpless if you don't have the actual cryptographic key used on the data that you want to decipher. Even if you have access to samples of plain text and their ciphered counterparts, you wouldn't be able to do too much. The RSA algorithm, for example, is a quite simple mathematical operation, well known to the public for ages. But it relies on the fact that, mathematically, the inverse operation would be borderline impossible if you don't have all the variables."
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5tszvw | Does repeatedly flicking a light on and off damage it? | I was told flicking the lights on and off quickly damages the light (maybe the bulb, maybe the switch?). Any truth to this? | Technology | explainlikeimfive | {
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"Probably. Sending pulses of power into things causes a lot of stress on them. This is particularly a problem with delicate things like light bulb filaments. Plus it annoys the other people in the room and if someone throws a shoe at the lamp that could also damage it.",
"> I was told flicking the lights on and off quickly damages the light (maybe the bulb, maybe the switch?). This is mostly for incandescent light bulbs. Changing the temperature of materials causes them to expand and contract. Generally making them colder causes them to contract and heating them cause expansion. A prime example is a hot air balloon where heating air causes it to expand and become less dense. (An example of a rare exception is water ice expanding compared to liquid water.) Incandescent lights work by heating a very thin wire until it glows brightly. This causes it to expand slightly and when power is removed it will contract again as it cools. When these cycles happen it causes fatigue in the material and it is much more likely to break at this point. Turning a bulb on or off is the most stressful part of its operation. So switching a light rapidly on and off is basically the worst thing you can do to an incandescent light bulb. On the other hand an LED bulb wouldn't care in the slightest, so it really depends on the technology.",
"Whenever you actuate a mechanical switch, you'll create a bit of a spark that can scorch the material. Over time, this can theoretically damage the switch. However, for the power levels you use in your house and the materials you're using for the switch, you're unlikely to cause much harm. This effect is more of a concern for your power company. In terms of what that switch is powering, there is a potential for harm but usually not much. For electronics, you'll normally have a great deal of capacitance involved in transforming the AC from your wall socket into the DC used by the electronics. For motors, you'll need a control board that likewise insulates them from direct connection to the power. A purely resistive circuit - such as an incandescent bulb - is already dealing just fine with voltage fluctuating back and forth. However, the mechanical nature of the switch does allow for the possibility of a spike in voltage beyond the normal limitations. This will probably only happen if you've worn down the mechanical switch (see above). More modern bulbs tend not to have this sort of problem due to the more complex circuitry. So the problem you're describing does exist, but it's a bit obsolete with modern equipment.",
"To summarize answers: Bulb: only incandescent. Even then, they are good for thousand on/off cycles. Your finger will wear faster. Switch: Your finger will wear faster. Bottom line: technically yes, practically not of any significance."
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5tt7l0 | Why do wireless companies treat tethering data differently than mobile data? | if i pay for data, does it really matter how it's being used? if i use my phone to stream netflix, or use it to tether to my computer to stream netflix, isn't the data being used regardless? is tethering more strain on the network than mobile data? if i stream 2gb on my phone or tether 2gb, what is the difference between those? seems some carriers have, for example, caps for regular data usage before they throttle, and a much lower cap for tethering usage before they throttle speed. but, my question is, isn't data usage just data usage? if you lease a car and you have X amount of miles, if you go over, you go over whether you drive with 1 passenger or 5, whether you drive to work or the beach, or day or night. miles are miles. | Technology | explainlikeimfive | {
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"There is no technical reason for this, and a few years back they did *not*. The bottom line is that they can make more money selling you an additional service.",
"Because they're greedy greedy pig fucks. They can make more money carving up your data into \"voice, video, internet, email, tethering, etc.\" then setting arbitrary limits for each type. So say people normally use 100GB of data, but they know people use 80% of it for tethering, instead they cut you to 80GB data, saying only \"high users\" go above 80 & sell you 50GB of tethering package, for an extra $50."
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5ttoxf | Why did Obamas (and probably Trumps) phone have texting, calls and music removed, but not internet access? | As he described by Obama in [this]( URL_0 ) video, his iPhone has had the camera, music and phone functionality removed, yet it can access the internet. Why did they remove all of these functionalities, most of which are harmless (such as music or phone calls), yet leave in internet access (which would probably be more of a threat)? | Technology | explainlikeimfive | {
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"Security, if he had the phone call ability there, someone could listen in on any conversation the phone was near. If he had the camera someone could watch, music im not too sure about"
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5tu5lf | What causes you to hear a high pitched noise when a device, which has been fully charged, is still in the charger? | Technology | explainlikeimfive | {
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"Small chargers today are switch mode power supplies. They work, simply said, by first rectifying the alternating mains current to direct current, then chopping it up again to pulses at a much higher frequency, transforming it down and rectifying it again. That sounds overcomplicated, but transformers for high frequencies are WAY smaller, cheaper and more efficient, which is worth the hassle. The transformer tends to make a sound, just like the \"normal\" ones make that familiar hum. It's depending on quality, cheap ones tend to have loose parts which vibrate and make them louder .. but normally the used frequency is way beyond our hearing range, so it seems dead quiet. If the device is charging and needs less and less power to do that as the battery fills up, the power supply has to reduce the power it delivers to held the output voltage at the same level. This is done by making the pulses of the primary voltage shorter and shorter. If the device is fully charged and in standby, it needs almost no power, but there is a lower limit how short the pulses can be, so the only choice the charger has is to drop (e.g., very simplfied) every 5th pulse completely or the output voltage would climb too high. But THAT introduces an additional frequency component at (in that case 1/5th) the normal switching frequency, which you can hear. Since the amout of dropped pulses is varying much with load, the sound tends to be quite irregulary and if you pick it your device to use it, while still connected to the charger, you can often even \"hear\" the fluctuating current consumption by listening to the changing sound.",
"The phrase is called coil whine. The highest rated comment nailed the basics. You can solve it easiest by replacing your charger, but if you like to ne a do it yourself-er, opening the charger and securing the transformers and coils with silicone, that should reduce or even remove the sound.",
"This is a thing? I have high frequency hearing loss so I wouldn't know but I've never heard anyone mention it.",
"So isn't the ELI5 here more like, the unit making the noise is receiving more power in a period of time that it transfers it than it's ment to?",
"What you're hearing is coils expanding and contracting of a buck converter, which is just a fancy way of saying a voltage converter that uses pulses(high voltage to low voltage probably). Basically what happens is that the correct voltage is generated by turning on the current to the coil for a certain amount of time and then turning it off at a certain(audible, if you can hear it) frequency. This causes the wire in a coil to expand from the heat that the current is generating and upon turning it off it shrinks again. This causes vibration in the air which is just soundwaves at that point. This frequency also varies depending on the current level of charge in your battery and how fast it's getting charged. Imagine the coil being a balloon where you fill it with such a frequency that you can vibrate the air and produce sound. That's what happens with a coil. edit: there is also a bit of magnetism involved in higher currents where the coil gets pushed apart when current is flowing. However I don't know how relevant this part is for small electronics. For superconductors one of the challenges is to keep the coil together because the magnetic field inside the coil can get strong enough to rip the coil apart."
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5tuark | Why is it recommended that new mobile phones be charged 6-8 hours before use? | Technology | explainlikeimfive | {
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"Lithium batteries have best long term shelf life when half charged. The battery will self discharge even not plugged in. So between your iphone leaves the factory in china, gets to dock warehouse in china, wait for the next boat, gets loaded, spends 2-3 weeks at sea, gets unloaded, waits for customs inspection, gets trucked to landing warehouse, distributed to local stores, unpacked and available for purchase, until you actually buy one, It's been a good couple of months since the battery was last charged."
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5tvbxu | Why do websites push there mobile version when its usually inferior in functionality and usability ? | Technology | explainlikeimfive | {
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"Load times, cleaner design and the perception is that if you're browsing on a mobile device, you want quick, easy access to the most common parts to that website. Not a complete experience, otherwise you would be on a desktop browser. Whether that is right or wrong varies from person to person but essentially, the website creator / business is just trying to be helpful by scaling back on what they deem unnecessary clutter for mobile browsing.",
"Web Dev here. Devs are always trying to make the UX (User Experience) as best as it can be. Sometimes deadlines have to be met and for the most part, mobile traffic has traditionally not been as important. This is all changing now as mobile traffic dominates the web. TL; DR traditionally lack of focus in the mobile area, but this is changing",
"To add onto points already made: because you pay for data and a well made mobile site uses less of it.",
"It also encourages brand/site loyalty. For instance, it is easier and faster to use the amazon app than to open a web browser and go to the site. This also means if I want to buy something, but don't care where, I'm more likely to use the amazon app than, say, open the web browser and shop around on walmart or target's website. The same with news sites, etc. It's easier to open a specific app, so people are less likely to stray.",
"welcome to r/conspiracies its because they want you to download the App! Most people have no inclination to download an App when they can view it on their phone browser. companies push the mobile versions(and engineer them to suck) so that you'll eventually give up and get the app. Cause it so much better. Ever hear people talk about that BaconReader app? Same shit. also, I know this isn't conspiracies....sorry. but I actually do believe this. Maybe not for everyone but definitely Facebook. Their stupid App needs access to everything on your phone...and I refuse to use it. /endrant. woah sorry didn't mean to rant",
"Lot of great answers here and they all point out important aspects of it, but the main reason native apps are pushed is User Engagement. I don't know the whys of it, I suspect it's a psychological thing where you feel like you \"have\" something and so you're more prone to using it, but the data backs it up; if you can get your users to install your app they're more likely to keep coming back and using your product or service which equals more ad revenue or more purchases or more brand recognition or whatever they're going for. Yeah, sometimes a certain product works better as a mobile app (games, super-rich UIs) but the main reason is engagement. There's something about the application showing up in that list that causes people to use it more and this is why companies push for it. It makes them money. They ultimately don't give a flying leap about the user's experience so long as they keep forking over (the two are usually related but not always). I'm not sure why this is since users were more than happy to jump ship years ago and get applications out of their Start Menu and into webapps like email, docs, spreadsheets, and even a lot of games, but that's how it is.",
"Over 60% (or more) of web traffic comes from mobile visitors. It's important for SEO to reduce bounce rates and increase time-on site. By not having a convenient mobile site will damage overall visibility (even on social pages) because people will leave. If a site \"pushes\" a mobile version then it's an old site and probably limited in great modern features. What people want is a \"responsive web\" structure that fluidly collapses across all browsers, and doesn't require a 2nd mobile design file which is expensive and outdated.",
"Because they control the advertising that's pushed out to you through their app, where Google (or whoever is contracted) controls the ads on their websites.",
"Because on average 65% of visitors to a website are on mobile, so the mobile version, despite sometimes having less functionality, is much more useable for the majority of visitors.",
"Because they allow the website to notify you when there are new updates to the content. This will keep you coming back for more content, and allow them to collect more ad revenue. It also allows for better tracking of what you are doing. It's much easier to track precisely what the use is doing on a native app rather than via the web browser. Also, some apps collect other information from the phone such as a contact list or a list of associated accounts for other apps like Facebook or Twitter.",
"Also websites that are considered mobile friendly or provide a mobile style sheet gain bonus points when it comes to website ranking in the Search Engine ranking process and are therefore more likely to rank higher in the SERP (Search Engine Results Page). So if a website has a half arsed mobile layout it could be either being improved or being used to help them gain a competitive edge in the ranking process in regards to their competitors. When you google a website you see (Mobile friendly) next to some results! (Along with the other reasons suggested)!",
"I haven't seen this listed yet, so I'll jump in late: Because it's a mobile device, which likely means: A) A smaller screen B) A much less precise instrument for pressing links (a.k.a., your fat-ass finger) These two things complicate each other. It's obvious that having a smaller screen means less being on a screen at a time (such as menus, links, or the information people actually want to see). Meanwhile, using a finger to press links means most people are less accurate, therefore links need to be bigger...taking up more of that precious screen space. (For instance, all the tiny links at the top of the Reddit Desktop Site, of your favorite subs. For some, such as WTF, my finger covers that, as well as parts of the links to the left or right.) To compensate, mobile sites will reduce the number of links available, more out of necessity than anything. Less options = inferior functionality, or in the best instance, harder to find functionality. To further complicate the issue...with HTML, there are simply less things someone can do than with their own programing. Such as having the now-familiar set of navigation buttons ever-present on the bottom of the screen that apps can do. Also, with a mobile web-browser, even with disappearing controls, precious screen space is taken up by controls that have nothing to do with the site. And, also, some of the aspects of HTML that designers often use are directed a cursor-control, as opposed to finger control The most obvious of these is what's known as \"Rollover\". When your cursor goes over something, it may highlight, change, or pop something up to tell you your cursor is on it, or to give you more information. There is no equivalent to doing this with a finger...a tap = a click, and even if something highlights when your finger touches it, you aren't going to know because your finger is over it! A mobile app, while at times less functional and certainly less familiar, will allow developers to create an experience designed for everything mobile has to do, rather than try to force of cursor-based world onto your finger. This is one big reason why, pre-2007, you did not see a lot of popular touch-screen computing platforms. It's not like there weren't touch screens available...there were modification systems to turn Macs and Windows machines into touchscreens. But the major reason they did not catch on was that shoehorning a User Interface based on a cursor into a finger is not easy. The most common complaint I heard was that the buttons on Microsoft Word or Adobe Photoshop were too damn tiny. It took one company to say \"F it, we'll build an entire new OS around touch interface\" to help the world open up to the popularity of it. This is still a longstanding UI issue, and one that is still being debated today. Microsoft Windows has spent years to create a unified OS that can do both, and particularly the first attempt was panned profusely. Apple continues to maintain separate OS's (Now 4 versions, including TvOS and WatchOS), but has faced difficulty in getting users to learn using all of them. Neither approach is failing, but both have faced significant challenges. That last part will be my final point, I promise: The mobile UI experience is constantly changing. First there were no styluses, now there are. Pressure-sensitive screens have given new ways for users to interface with apps, but not all phones have them. Not to mention the controls for voice-interface that are all over the place. There are yearly changes to the mobile environment to try and improve user experience...but that means developers have to be on a fast learning curve to learn how to implement them...and then hope they aren't abandoned and changed. And that's before talking about how to implement the voice control abilities on iOS are different than doing it on Android (not to mention Samsung's separate stuff), doubling or tripling to workload before you even talk about Microsoft's. It's a complicated, extraordinarily fast-moving world in Mobile, even for the already quick-changing tech world. Developers are playing catch up constantly, and that means the users are far behind... And there's no easy solution, other than to hope that the UI world finds its groove in the next few years... Oh, rumors say the home button's going away on phones??? Oh boy...guess you're going to have to tighten your grip on the reins of this Mobile OS life for a few more years. EDIT: Yes, obviously cost was another reason why touchscreens were rare pre-2007, but popularity would drive that...the more you can mass produce, the lower production costs can become. And the demand just wasn't there...and while I can't produce scholastic proof, my experience of being in tech since the 1990's will tell you the lack of satisfaction of touchscreen interfaces helped limit that demand.",
"Also wtf are you stopping pinch to zoom, it's the nicest thing about a small screen and we have to put up with stupid websites disabling it.",
"So pushing a mobile version of a website is different than pushing a mobile app... and that's why the answers are all over the place. Websites push a mobile version because the desktop version usually sucks on mobile. A mobile version fits better on smaller screens and doesn't take as long to load. You shouldn't be asked to view the mobile version on your phone, it should just happen when you visit a website. Apps on the other hand are pushed because they have more power. You may forget about a new website you visit, but if you install an app, you'll see it every time you swipe through your homescreen. Other than being on the home-screen, they can send push notifications, they can collect more data, get your location, have in-app purchases, connect to your social media, etc. So apps are more addictive and habit-forming, which means they make more money for companies."
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5tw93c | Why is it possible to tell if you're watching an SNL skit just by the quality of the video itself? | Do they use like some sort of custom frame rate or some unique combination of zooming and panning back? The video/film quality isn't like any other TV show or movie I've seen. | Technology | explainlikeimfive | {
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"It's because the lighting is different. It's very similar to soap operas. They use evenly lit lights across the whole set, meaning that lighting is a lot less used for character focus and mood. The benefit is that they don't have to do a bunch of lighting work during short turnaround times between filming skits, and they can do continuous takes and have characters move around the set, all while looking pretty uniform. Read more: URL_0",
"* \"video\" camera quality instead of \"film\" which is much more expensive (there's an fps and color difference) * bright studio lighting * with a lot of sets for different skits, the sets are usually small and cramped * ^-- because of that, no establishing shot or wide room shots * also rare for camera panning to happen * basically there's like 3 or 4 shots possible when sitcom sets can have dozens"
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5twg4z | If passwords are stored as hashes why is it more secure to have passwords with numbers, capital letters, etc. | Technology | explainlikeimfive | {
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"If the password database is stolen, or a security hole is discovered that lets the attacker try tons of combinations, they will probably immediately try a dictionary attack. They'll check to see if any of the hashed combinations match common words and common passwords. This means that some will probably immediately fail as many people use the laziest passwords the rules allow. However, unpredictable capital letters or numbers ups the number of possible combinations tyou have to check to get the password, often to the point where it's so extremely time consuming that you just can't check all the hashes in existence.",
"Because it's much easier for a computer to guess \"password\" than it is to guess \"Leno43_dais%\". The protection doesn't come from the fact that it somehow becomes harder for attackers to attack the hashes or server, that's always difficult. But an attacker can try out millions of passwords a second, the idea with password constraints is to get people to use hard-to-guess passwords instead of the name of their dog."
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5twllf | why do vocoders require that weird tube in the person's mouth, and not a microphone? | Technology | explainlikeimfive | {
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"Ah, perhaps you are conflating the all electronic vocoder (no tube) with the Heil Talk Box, made famous by Peter Frampton in 'Do you feel like we do'. The vocoder takes a microphone input and a synthesizer input, and mixes the two so the voice modulates the synth sound. It works electrically. Example: Kraftwerk's 'It's more fun to compute'. The Heil Talk Box has a speaker inside, and a tiny amp circuit. The guitar is connected to this, and the box sits at the guitarist's feet. The tube goes up the mic stand, carrying the speakers sound into the players mouth. Now the player can modulate the guitar tone by moving their mouth- an acoustic process. The microphone picks this up, and the usual big guitar amps are muted while the talk box is on. These two gadgets both make a hybrid voice and instrument tone in completely different ways.",
"You mean a talk box? The tube basically pipes the sound from your instrument into your mouth and you use your mouth to modulate the sound URL_0",
"real Talkboxes like Frampton used actually shoot sound waves into your mouth. after messing with one for about 10 minutes your gums feel like they are bleeding."
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5txqlw | What, exactly, is a "bit", as in the fact that the Nintendo 64 was "64 bit"? | Technology | explainlikeimfive | {
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"In computing terms, a bit is a \"binary digit,\" which is short just means either a 0 or a 1. When we talk about Nintendo64 being \"64 bit,\" its the same as having as 64 bit computer: the instructions used by that processor is 64 bits long. While this is useful, a 32 bit machine has 2^32(a little over 4 billion) possible instructions, which nothing even comes close to using. What actually makes this good is how much *memory* a 64 bit system can have. When we talk about the max amount of memory (RAM, to be specific) a computer can have, we need to realize that every single \"piece\" of memory has to have an address. This way we can say \"piece of memory #48\" and know exactly what we are talking about. In a 32 bit system, we can only address 2^32 \"pieces\" of memory (which for reasons I won't get into is usually 8 bits, which we call a byte). Now, ~4 billion bytes *sounds* like a lot, until I say that 4 billion bytes is only 4 gigabytes. So a 32 bit machine cannot use more than 4 gb of RAM, period, end of story. Now, a 64 bit machine can use 2^64 bytes of memory, which is ~10^10 or 10 billion gigabytes of memory. Clearly an upgrade. Edit: I should note that while 64 bit lets you have more RAM, the N64 specifically did not make use of it. The N64 only had 4 MB of RAM, not even coming close to the 4 GB of RAM upper limit for 32 bit.",
"Imagine you had a calculator that could only add a 1 digit number. So to add 13+18, you'd have to do it like a five year old learning to add. You add the 3 to the 8, get 1 and carry the one. Then you add one and one, and get two, then you add the one you carried, and get 3, so you have an answer that's 31. Then you go from a 1 digit calculator, to a 2 digit calculator. This one can add 13 to 18 and get 31 in a single step, instead of the three steps and keeping track of the extra digits it took the 1 digit calculator. A bit is a number, just like 13 or 18, except it's expressed in binary. So going from 32-bit to 64-bit means you've got extra digits in the calculator, so you can do stuff in a single step that otherwise would require multiple steps and a scratch pad to keep track of intermediate values. That usually materialized in the system doing new things that would have been too slow or too complicated on the old system. One easy example of this is the increase in color depth from the (8-bit) NES to the (16-bit) SNES.",
"Unfortunately asking a Computer Science question will yield a lot of verbose nonsense for some. I'll simplify what the people are trying to say. Essentially a computer has on and off values, 0's and 1's. And to be more specific I believe it's high(1)and low (0) voltage. That is a bit. How the computer can be told instructions. A 64-bit instruction means the computer takes 64 of those (usually) to take commands. The only reason bigger is better is that there are more combinations so more precision and other things are enhanced. To compute the possible values you do 2^n where n is the number of bits used. 64 = 2^64 opposed to this instruction sets predecessor 32 bit that has a 2^32 set of combos.",
"a bit is the smallest amount of data that a computer can understand. it is a single binary value that can be either 1 or 0; the term is short for \"binary digit\", because 0 and 1 are the two symbols that are used in base 2 math, like the ten digits 0123456789 comprise the ten symbols that are used in our familiar base 10 world. now, this explanation of bit-ness is going to be long, but you really won't understand it without some basic computer architecture background. it's not as hard as it might sound, trust me. any number you can think of can be represented as a string of bits - all you have to do is convert from base 10 to base 2. we can do math by taking base 10 numbers, converting to base 2, doing our math in base 2, and converting the base 2 result back to base 10. (in a real computer, we only convert things back to base 10 if they need to be shown to humans.) in a computer processor, the \"arithmetic logic unit\" is the piece of hardware that does basic math. its purpose is to take a number represented as a string of N bits, another number that is similarly N bits long, perform a math operation on them (addition, subtraction, etc), and produce an N bit number as a result. we use terminology such as '4-bit' and '256-bit' to indicate how long of a bit string a particular ALU is capable of processing. how do we get input values to the ALU? the processor needs to be able to store and transport chunks of information that are exactly N bits in size, in order to provide the ALU with data to operate on and hold the result when it's calculated. the storage inside the processor used to hold values that are currently being processed (like our result) is called \"registers\" or a register file. each individual register must be N bits wide in order to hold our information. the data pathways which transport information around the processor must also be capable of moving N bits at one time. we call these N-bit registers and N-bit buses. now, what are the consequences of having a system designed around one particular bit-ness? the maximum number that can be represented by an N-bit binary string is 2^N; for a 32-bit system, that would be around 4 billion. a value like 5 billion wouldn't fit in 32 bits if we converted to base 2 - it would require 33 bits. lower bit-ness limits the absolute size of numbers that can be used in our processor. the processor needs to access memory, or RAM. each location (byte) in memory is numbered - the processor uses these \"memory addresses\" to keep track of what information is located where. the same registers are used to store numerical values for math operations and memory addresses, so a hypothetical 32-bit system could only use memory addresses from 0 to 4 billion. our processor would be described as having a \"32-bit address space\". so, bit-ness for a processor affects the size of the maximum numbers that can be used, the width of the ALU, the size of the registers and buses, and how much memory we can access. what are the benefits of 64-bit over 32-bit? for one, you can use more than 4GB of RAM. if you need to count the number of microseconds that have gone by since you started a game, a 32-bit system could count up to 1 hour and 15 minutes, while a 64-bit system could count up to 584,000 years. if you are doing damage calculations on huge bosses, you could go above 4 billion and well into the 1,000,000,000,000,000,000s if you so desired. what about the disadvantages? now most of your data has to be stored as a 64-bit number instead of a 32-bit number, making programs larger. everything in your processor has to be twice as wide - a bigger ALU, bigger registers, and wider buses. this means more heat, more space, and more transistors. if your program only or mostly does 32-bit math, then power and space is being wasted compared to a native 32-bit system."
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5ty232 | What the difference is between x264 and x265 video encoding and which is better | Technology | explainlikeimfive | {
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"The actual encoding is called h.264 and h.265; x264 and x265 are an implementation of that standard. The h.264 encoding is older and more widespread. There are a ton of devices that can do h.264 very quickly and/or very energy efficiently. The h.265 encoding is newer and claims to outperform h.264 in many ways, though many devices don't support it (though virtually all PCs, tablets, etc will support both; the devices that won't are very low power, embedded devices and the like). In practice both encodings have a *lot* of knobs and dials to play with: you can get a lot of performance out of either, or you can tune either to be absolute garbage. On average, you should expect h.264 to take less processing but to leave you with a bigger file, while h.265 will likely take much more processing to encode, somewhat more processing to decode, and will leave you with a smaller file. Which one is better depends on your use. If the goal is to wind up with as small of a file as possible (e.g. if you're trying to archive a bunch of videos on a hard drive with limited space) then h.265 is going to be the way to go. If you're trying to compress videos to watch on your tablet then perhaps consider h.264: the lower processing load means that you'll get a bit better battery life. In most cases expect h.265 to be the better choice; it's the more modern standard, though hardware hasn't quite caught up with it yet. As for x264 vs x265, these are software projects that are fairly widely used in programs like FFmpeg or HandBrake. The x265 project is based on the x264 code so they're very similar to one another, though obviously they implement different encoding. The choice between them should be based on h.264 vs h.265, not on the features of x264 vs x265.",
"The ELI5 answer is that x265 uses better compression, so you can get higher quality with a lower file size. The penalty you pay for that is that you need much more computing power to decode it - there's hardly any video hardware that supports it so the CPU has to do all the work. So for which is better, that depends on whether you have more CPU power to spare or more diskspace."
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5ty4zj | How did television studios make words like show titles appear on screen before computers? | Sorry if that's worded poorly. I mean like when the words "I Love Lucy" or "The Honeymooners" or screen credits would appear over the live action footage. | Technology | explainlikeimfive | {
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"I actually worked in TV before computers. We would make the titles with press-on letters (I forget the brand name) and shoot them with a camera. The title camera would be combined with the live camera in a device called a \"luma key\" that would switch the live camera off and the title camera on everywhere that the lettering appears, based on the brightness. This was with monochrome cameras. With color cameras there was a device called a \"chroma key\" that would switch based on hue, usually tuned to blue. The same device was used for example to put graphics behind the weather man. You had to be careful the talent didn't wear any blue clothing. EDIT: found a web page that shows a switcher with built-in luma key, and explains how it works: [Switchers]( URL_1 ). Scroll down to \"Keys - Internal, External, Matte.\" EDIT 2: I remembered what the letters were called; Tactype. You can buy a sheet of it here: [VINTAGE TACTYPE Lettering 12 x 8 Sheet Dry Transfer 5514 Futura Medium]( URL_0 )",
"Movies have had titles since the 1880s/90s. Lots of methods. Shoot bright titles on a black background with one TV camera. Combine that feed with a feed from another camera and you've got titles over, which you can fade up & down, zoom in and out, roll, whatever. Before computers were used in TV there were devices like Chyrons which substituted for the bright letters on black background and the second camera and gave producers a lot more variety and flexibility. But the basics: 2 feeds and one can be a computer or just a piece of paper.",
"The first live television graphics(commonly called 'supers' or superimposement at the time) were created at a national political convention(iirc Republican National Convention) in the late 60's. They were trying to figure out a way to announce the speakers without having an announcer say the name of every speaker that came up. The director and technical director were at lunch at a diner that had a black menu with white letters. They came up with the idea of using a luminance key to overlay the names. They bought the menu and all of the letters off the diner for less than $100 and that's how the first 'supers' were done before computer graphics. Other ways discussed in other posts were used but as far as I know that was the first. Source: Technical Director for 18 years. EDIT: [Mr. Hewitt swept into the early medium of TV with a series of bold editorial and technical ideas. He was a leading champion of location shooting to cover spectacular breaking stories. He introduced cue cards that forced anchors to look directly into the camera, only after his experiment with Braille went nowhere. At the 1952 national political conventions in Chicago, he created a way of superimposing people's names under their images on camera. The idea came to him at a diner that had a menu board with rearrangeable letters. When the waitress came to take his order, he replied, \"I'll have the board.\" It cost him $45.]( URL_0 )",
"They would have long scrolls of black paper on which they would mount words made of white letters. They would have two cameras, one focused on the scroll and another focused on the scene in the studio, and they would electronically combine the two images. This technique was used into the 1970's. Source: I once knew an artist who was employed to make these long scrolls.",
"I remember some time around 2002, Fox had a baseball game where each inning represented how TV broadcasts looked in each decade. For the 30s, I remember seeing a \"floating hand\" place a card showing the ball and strike count.",
"Heynony is correct for more recent live TV titles, but older TV and movies, they used optical titles. These are titles that are combined with the base footage as part of the printing of the film, basically think of cel animation, where the negative is exposed by light passing though multiple layers of film. The title layer or layers can be hand drawn cels, just like in animation, or photographed text. And of course many complex combinations of these ideas to achieve complex effects.",
"I was disappointed when I went to a taping to The Price is Right years ago. The flashing ring of lights around the screen during the introduction was just a string of Christmas lights that was mounted to the perimeter of the camera lens. Afterwards, all I could focus on was how I didn't notice that for years while watching the show.",
"Another technique that you'd probably appreciate is matte painting - literally painting an exotic landscape on a glass slide, then putting the slide over the camera lens.",
"IIRC, they also occasionally used reflections on glass, similar to heads-up displays or teleprompters. They would film a scene with an angled glass pane between the camera and subject. Another image of very bright text on a dull background would be projected towards the glass. Only the brightest part, the text itself, would reflect off the glass - the rest would remain transparent. Thus, you'd see the text appear to be floating in front of whatever was seen through the glass.",
"Many shows were made on film and used the same method as movies did. The Honeymooners was done live and titles were keyed in from a special camera which pointed at a scrolling paper roll. Even before the personal computer, the Chyron Corporation made special-purpose computer based character generators for TV production in the 1970's. They took up an entire rack and used core memory and 8\"floppies. They had very high quality characters.",
"There is a really great example and explanation of how they made the HBO intro in the early 90s without computers. This example is especially neat because the final result looks CG. URL_0 The making of the logo starts here 5:18",
"The tv studio I used to work at had an old barrel/drum that had been used 'back in the day' for credits. Sheet after sheet of credits were taped to it and a camera was aimed at it while a production assistant would slowly turn the crank. You know, to \"roll the credits\".",
"Another interesting thing is during the Apollo flights the computer screens in mission control were actually television screens showing a feed from a camera which was pointed at a projection screen, the various words, etc were projected on the screen and displayed on the tv screens, in this way they gave the illusion of much more advanced computers than was actually available at the time",
"To maybe add some insight, old tv is made with analog signals, which is basically a voltage going up and down. Connecting voltages in series adds them up (physics does that for free for us) and in parallel averages them out. Now since that source signal is synched to a certain frequency which has a predetermined start, you can do all kinds of things to the signal with variable resistors, capacitors and coils for interesting results. A friend of mine recently disclosed that his grandfather used to do this type of thing for a hobby, and there is still some old gear stored somewhere. I can't wait to try it with our FPV signals, which are basically wireless analog tv transmissions :)",
"I worked on TV, The standard Character Generator was the Aston: URL_0",
"I remember seeing the machine used to make star wars' intoductions at a museum. It's like a big box with a camera pointed directly in it, and something physically turns the part with the introductions.",
"It's worth noting that in between the era of shooting titles on cards on camera and computer-based television graphics, there were dedicated devices called Character Generators. You could type text into them with a keyboard and they'd be stored in arrays of analog capacitors that could replicate what you typed earlier on command and insert the text into the video signal.",
"I worked in a school studio before computers. We wrote our titles and credits etc with a rapidograph pen with white in on black paper. WE had an easel witha camera on a bench. We'd load in the first card, then superimpose it over the live picture from that cams slider. Then we'd fade it out, switch to the next card and wait for the directors cue to switch again...",
"sorrta similar... My uncle worked as a technician in the early cable days (1960's) in a small eastern Ontario town (Pembroke) and I remember in the back of the cable office, there was a rotating drum in front of a camera. It was about 2' around, 6\" wide drum that rotated about 4\" every 30 seconds or so. There was a camera in front of it. They would place advertiser cards or typed announcements on recipe cards, attach those on the drum and that was one of the cable channels! If you snuck in there and placed your finger in front of camera, you were on channel 6! fun times...",
"I've seen plenty mention luma or chroma keying, and the source of the titles being shot with a second, synchronized camera. However one part nobody's mentioned: the system I saw at a local college studio had two slide projectors aimed into an optical setup with the tv camera coming out the other side. (There was a 16mm film projector facing into this setup, too, so I guess it worked for film transfer as well). The titles would be shot onto the slides (white letters on a black background), and divided between the two slide projectors so the first slide was in projector A, second in projector B, third in projector A, and so on. Only one projector showed at a time through the camera, and each time you switched between projectors, the projector that wasn't viewable changed to the next slide, so the change appeared instantaneous. So that's how it was done, or at least one way it was done, for successive titles that didn't scroll. Later the same college got a color system, and a computerized character generator. The character generator was still black and white, though. Another device created a full screen of any color you want (using analog knobs, probably Hue, Saturation, Value or something like that) and Luma Keying off of the generated characters was used to switch between your live video and the full screen color device; resulting in the letters being colored. You could also make the full screen color device do a range of colors across the screen, giving your titles a rainbow effect."
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5tzjyl | how can the government track GPS devices? | If I understand correctly GPS works because my cellphone receives a signal from a few satelites that basically represents the time on the clock of that satelite, and by reading the different times my phone can work out the distances to the satelites and map my location. Now I've been told that a government/foreing military can find me if I use GPS (this was a conversation within the context of a military unit still using compasses in certain context because the GPS could be tracked). I don't understand how this would work given the above process. ELI5? | Technology | explainlikeimfive | {
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"You're correct about GPS. A pure GPS device is just a radio receiver, it can't be tracked; and GPS satellites are just broadcasters, they have no idea what devices are listening. Your phone, though, uses a map of WiFi network identifiers and triangulates by cell phone signal as well, and that's trackable - heck, the phone company has to know what tower your cell phone is closest to for the technology to even work. Both kinds of devices may save a record of your movements, which could be viewed later."
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5u1a7w | How did cameras on spacecraft film, and transmit data before we had digital cameras? | When I saw the Voyager Pale Blue Dot photo on the frontpage today, this sparked that question. I know Voyager was sent up at the dawn of digital photography, so I guess I can assume that they had that tech on voyager. But what about all the other probes and maned-missions before? How could they transmit images back in an era of film photography? | Technology | explainlikeimfive | {
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"Radio waves, just like we still do today. If you want an example, think about how television worked in the 1940's and 1950's. Take an image and transmit it via radio to a receiver.",
"Analog. Prior to 2009, most TV broadcasts were analog signals captured with analog video equipment and recorded on analog media. The [cameras used by NASA]( URL_0 ) on Voyager 1 used to take the Pale Blue Dot are called vidicon tubes, and they are kind of like the old CRT displays running in reverse. At the end of the tube opposite the lens is a plate that builds up a charge as light hits it, then the charges on the plate are scanned using an electron beam to generate an analog signal just like old-fashioned TV. The signal is run through an amplifier and broadcast back to earth as a slow-scan TV picture. The system more or less works like the TV systems used from 1950-2000.",
"Spy satellites used to expose a roll of film, then get it back to Earth with a reentry device and a parachute. It came down with a radio direction finder. This cost a lot of money. The satellite would run out of film. They switched to television transmission of images very quickly. Film had better resolution for a while. But techniques improved rapidly so transmission of images rather than film happened quickly."
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5u1exw | Browser Fingerprinting | I've visited [ URL_0 ]( URL_0 ) and somewhat get the concept of Browser Fingerprinting, but how do they figure out who exactly you are? Like, can they look at these browsers characteristics and say, "Hey that's specifically Larry Jones from Nightmute, Alaska"? Yes! (You can be tracked!) 36.67 % of observed browsers are Chrome, as yours. 3.58 % of observed browsers are Chrome 55.0, as yours. 56.59 % of observed browsers run Windows, as yours. 31.97 % of observed browsers run Windows 7, as yours. 66.51 % of observed browsers have set "en"as their primary language, as yours. However, your full fingerprint is unique among the 314628 collected so far. How is this unique if these metrics are so common such as using Chrome and Windows7 and have the language set to en? | Technology | explainlikeimfive | {
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"Because each additional piece of information makes things more unique. So how many people share your browser, browser version, build, is, OS version, os build. They also look at the browser resolution, if you have flash installed, the browser language, the browser plugins. A big one is they can have the browser generate an image and the exact data of the image will be different based on the browser, os, and video card. They look at what fonts are installed, whether the browser supports HTTPS, whether you have the Do Not Track turned on and more. The odds that a multiple people will have all of the EXACT same settings and hardware for everything gets smaller for each additional thing looked at."
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5u1qq2 | What is an api and what are restful api's ? | Tried reading explanations on the Internet ; learnt a few things about what apis are but couldn't make ahead or a tail about what restful apis are? | Technology | explainlikeimfive | {
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"API = Application Programming Interface. It's basically just a set of methods and properties in some software (usually someone else's software) that you can call or request to do stuff using your own software. REST = REpresentational State Transfer. REST or RESTful web services are a common way of accessing an online API. You make a request to a certain URL with a certain set of parameters and it will send you back some information. It is a \"representational state\" because it returns the current \"state\" of the data you requested, and if you make another request it doesn't remember you, your previous connections, requests, or responses. It just does what you ask in the current request."
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5u2nkx | What is a Linux Kernel? | How do you make one? How do you configure it? Where is the Kernel? Can you look at it? Can you change it? Do you want to change it? What changes can you make? Other questions about kernels. | Technology | explainlikeimfive | {
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"A kernel is the core of any operating system. it has complete access and control over everything in and pertaining to the system and is the first thing loaded of your system. The kernel is responsible for, well, most everything low level. They are the masters of your system, the backbone of computing, the framework for everything your machine does. If it's important, close to the OS, connects hardware pieces together, or is low level it most likely goes trough the kernel in one way or several. The kernel is usually located in a protected memory space where no applications can touch it (for what I hope are obvious reasons). > How do you make one? A lot of low-level programming. You need to have pretty good understanding of the ins and outs of how your hardware operates since you'll be handling most of it directly. If you are intending to write one read every single guide you can find. > How do you configure it Depends a bit on the distribution, but there are a lot of guides for that sort of thing. [for instance this one]( URL_0 ) > Can you look at it? Sure, the Linux kernel is open source, anyone is free to examine the code and make their own version. [The github repo for the Linux kernel is here.]( URL_1 ) > Can you change it yes. > Do you want to change it? Personally? No. If you don't know what you are doing? most likely not. But if you find something to be off with the code be free. Plenty of people do change it to better fit with their needs and purposes. > What changes can you make. all of them, the code is open, you can change whatever you like. Just be careful if you intend to load your custom kernel into your machine, being all powerful on your system leads to some problems to avoid.",
"So back in the day, everybody who wanted to do anything with a computer had to start from scratch. If you wanted to put letters on paper, or data on a tape, or punch holes in cards you had to write all that procedural code yourself. That code looked very terse and it was made up of \"cram number into location\". Some locations in memory would start the motor of the tape drive. Other locations would turn the magnets of the write head on and off. Another might move a print head. Another would cause the print head to slam the ribbon against the paper. It was all really low-level, annoying, and repetitive stuff. It was really annoying. Really. Annoying. And so error prone. Worse still, if you and I were both going to use the tape drive (not at the same time) we'd both have to write our own \"device driver\" code, and we both had to pick how we'd arrange the magnetic spots to represent our data. And if we _both_ didn't do all that exactly the same way then _my_ code couldn't read _your_ tapes. This became ridiculous. There was all this data being used and saved but nobody could share it, and everybody was wasting a lot of time re-inventing the wheel, so to speak, by having to write their own drivers. So they started making \"libraries of code\". The libraries would have \"include books\" for the various things like operating the tape drives and the printers and so on. When I decided to use the printer in my code I could tell the compiler to \"include the book with all the printer code\". So things got better. But computers weren't all that fast. So it became obvious that even re-building all the drivers for each program was a waste of time. So they started to make \"runtime libraries\". Basically they'd compile the human-readable code into a machine readable format, then include that. It was much faster. But computer were _really_ _really_ slow. And it became obvious that \"most of the program\" you were \"loading into memory\" was from these libraries. So if you and I were taking turns using the computer, I'd erase everything you'd put in, and then put in my stuff. When it was your turn you'd erase what I'd put in and put in your stuff. This took a _lot_ of valuable time. And it was a waste because massive fractions (sometimes like ninety percent or more) of our two programs were the same code from the same libraries. So wouldn't it be cool if we could leave the common stuff in there and just load our unique parts? Basically what if we condensed the stuff we needed to operate the system hardware into one blob that would just always be there? But there were _way_ more libraries than there was memory. Like one killobyte of memory was a _huge_ computer. So they paired down only the most common parts. The parts that read the tape drive or printed on paper. This smallest common part was the \"kernel\" of the \"operating system\". Then the extra parts would be used on demand and the individual programs would have the best running time with the best available memory. Over time computers got bigger. And so did operating systems. Instead of just barely enough to run the tape and disk drives it became desireable to be able to use all sorts of things. So \"the kernel\" of an operating system is the minimum needed to run the various hardware, the minimum needed to get programs into and out of memory, and the minimum needed to let programs ask the kernel to operate the hardware for them (instead of needing the programs to operate the hardware themselves). Outside of the kernel, there are piles and stacks of utilities and lots of files containing \"optional\" drivers. For instance, in windows, you don't need the real-time game-to-screen rendering parts to copy files around. So the game-to-screen part (\"Direct 3D etc\") are only loaded into memory as needed. Just like you don't need your game loaded in order to use Word. So every operating system has a \"kernel\" (as in \"kernel of corn\" or \"seed\") at its metaphorical center. Then it has things like optional drivers and utilities (like the program \"copy\" on windows that you use to copy files) and all that stuff. So back in the day there was an operating system called Unix. And it was very expensive. But it was very good. So this guy, Linus Torvalds, wrote a \"Unix Compatable\" kernel and name it Linux (e.g. replaced the first letter with his initial) and gave it away for free. It was very popular. And there was already an organization called \"GNU\" (which stood for \"GNU's Not Unix\" -- a little joke that) that was trying to make free versions of all the main Unix utilities (like \"cp\" as in \"copy\"). The combination of Linux and GNU software is what's now known as \"GNU/Linux\" (e.g. \"GNU over Linux\") and is what you know as a \"linux distribution\" or whatever. So the Linux kernel is a big pile of software that knows how to make the hardware do stuff. And you can get it for free. And you can change it and compile it for yourself because, unlike Windows, when you get a copy of Linux and GNU utilities, you get all the source code (if you want it). So yes, you can look at it. Change it any way you like. And so on. The only rule is that if you change it, and then give the changes to someone else, you _MUST_ give them the source code so that _they_ can look at it and change it if _they_ want to."
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5u2qtu | What is the process professional Animator use when making movies? | For example, how does. Say, a Pixar animator go about animating? What program does he use, and what goes into it? | Technology | explainlikeimfive | {
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"Pixar uses their own RenderMan software to make movies. For 3D productions like their films, the process is a sort of hybrid of live action and traditional animation production since it's creating virtual 3D sets. That means in addition to regular animators, there are people who make textures, do lighting, move the camera around the scene, etc. This is based around storyboards, then preliminary animation is done with low quality rendering so the artists can get an idea of what everything looks like. Once everything is correct for a scene, it's fully rendered to create the final product."
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5u46wa | How easily can a modern vehicle be hacked? | With modern vehicles essentially being driving computers, how difficult is it for someone to get access to the vehicle's computer? Does the hacker need direct access or can it be done remotely? If it can be done, how much control over the vehicle does the hacker gain? | Technology | explainlikeimfive | {
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"Someone else can write a better answer, but I'll try a quick one. Yes, it's possible. Cars with wifi are on a network, and many of them don't have the necessary safety precautions to prevent hackers from controling the engine. Check out [this link]( URL_0 ). Hackers shut down the engine of a running car to show off that they could. It may be possible to actually drive and steer these kinds of cars. However, while it's possible, it's very difficult and unlikely. I wouldn't personally buy a hackable car, but I don't think you're at any risk. The best hackers are often the ones trying to fix these exploits"
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5u5055 | How does a universal remote work? | Technology | explainlikeimfive | {
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"Each kind of remote has its own special language. Universal remotes know all of the languages but you have to tell them which one to use Or it pretends to be what ever remote is needed to do what you want",
"The way a remote works in general is that the remote is programmed to send particular infrared signals to the tv, which it then reads and interprets. Universal remotes have 2 types; preprogrammed, which are loaded with the \"codes\" or signals that a device requires to control it. The second type is a learning remote. It reads the signal from an existing remote or tv and mimics it."
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5u60mw | How do websites detect whether you are you using an ad-blocker or not? | I know about the bait JS but could you explain that part more too? | Technology | explainlikeimfive | {
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"Basically, they create a \"fake\" ad, code that uses common words adblocker uses to flag ads, and then checks to see if that code loaded, or not. If it didn't, adblock snatched it up, and it says \"hey. stop that\" I.e. ad fake = newAd(); load = check fake.isLoaded(true); if not load==true run gotcha_adblocker!():"
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5u6m4r | Why are some beautiful people not photogenic? | Technology | explainlikeimfive | {
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"Not an expert, but I think it has something to do with depth perception. Many people carrying a bit of extra weight look unappealing in still photos because when reduced to two dimensions they just look wide like a tent. In motion or in real life we can make out their three dimensional form, which is more appealing I.e.. a bulky man's musculature or a bulky woman's curves are more noticeable with movement or in 3D.",
"Actually, not funny joke from photographers' life. Two of them chatting: -Hi, I heard you've got a new girlfriend? Pretty? -Well, you know, depends on a lighting scheme. So as a photographer I should say this joke is kinda realistic. Lighting is the key in portrait shooting.",
"Candid photos are almost always unflattering. Actors on film and tv undergo a lot of preparation to be ready for the camera (makeup, hair, wardrobe, etc.). You can be considered 'photogenic' if you can take a good candid photo, but I can guarantee even photogenic people don't have good photos taken of them, every time.",
"Many attractive people are perceived as attractive because of a combination of voice, posture, body language, etc. A photograph will miss some of those characteristics (anything to do with sound or motion).",
"Some people just simply do not know HOW to be photographed. Eyes get too wide for no reason, don't elongate the neck so they emphasize the double chin, don't feel comfortable and every shot looks awkward and forced. Doesn't matter HOW pretty/handsome you are, if the photographer doesn't help... or have a clue how to take a photo (in the case of the dreaded selfie) it's actually quite difficult to get a photo that looks any good. As a photographer, technical skill required to actually USE a camera is actually less important than creating a connection with the model and making them feel at ease having their photo taken. Also if they are using a wide angle lens up close for portraits (i.e. 35mm or wider), the distortion alone will make the face look all bloated and wide. Very unflattering. And of course lighting. Good light, be it natural or created is just as important and helps to sculpt the face to create a beautiful image. Just my 2 cents.",
"I think that there are a few things at play. A photograph is a still moment-some people look great (to you) because of how they move, or posture, or facial expressions, that are super difficult to accurately capture with a photo. Also, a good photographer is hard to find. I am an absolute mess, but I only point and click. I've found that people with good pics consistently know how to pose for that. I am a fan of pinups, and the combination of a good pose and a good angle works wonders.",
"The Focal Length of a lens has a lot to do with how a person looks on a camera. As a result, certain lens types will make a person appear differently than they do in person. Because our brains do a lot of processing of images, it is hard to point out exactly why, but in my personal experience, Each person will look the most photogenic (for this explanation I will use \"better\" to describe this) with a specific focal length lens. Take a look at the link at the bottom of this post for a visual example of this. To explain focal distance in this context, a fish eye lens has a very short focal length. This will make people appear more rounded. A longer focal length will by contrast make people appear flatter, but actually let you see more of their face. The distance the photo is taken at also factors in, but this is the general sense of it. In the link below you will notice that with a small focal length, you cannot see her ears, yet at a further focal point, you can. Finally, since cell phones are the #1 source of photos for most people, it is important to note that the zoom on most cell phones is done digitally (the photo is just cropped to size) rather than changing the focal length. Therefore, people will appear either photogenic, or not. There is no changing focal lengths unless you get some sort of add on lens kit for your phone. I hope this explanation helps, but for the TL:DR crowd, Focal length is a huge factor in how people look on a camera. [Visual Link]( URL_0 )"
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5u6rog | how a phone can actually trigger a bomb from a call | Technology | explainlikeimfive | {
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"The vibration function in the phone can be used to trigger the bomb. A terrorist using it as a trigger simply removes the motor causing the vibration and connects the circuit to the bomb /waves hi nsa",
"Remove speaker from phone, wire speaker wires to detonation device. Very simple. Hard to fuck up. Lest you leave the phone on vibrate"
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5u738m | Can someone please explain the mechanisms behind "overcharging" and damaging your phone battery? | I heard that if you leave your phone on charge when it's on 100% it can damage the battery. I was skeptical, but I have no knowledge of batteries or technology. Could someone please explain this to me? I'm sure most people do this, so hopefully will be of some interest. Thanks in advance. | Technology | explainlikeimfive | {
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"It used to be possible with older batteries, and you also had to avoid charging it too often as well, but modern batteries cut themselves out from the power when they're fully charged. They will also leave the battery with a very small amount of charge when the phone dies to prolong the battery life and keep the internal clock going too. Basically, lithium batteries would overheat when left plugged in, which would cause damage to the battery over time. * Source: [Older batteries shouldn't be allowed to overcharge because they would overheat -- \"modern devices are way smarter with managing power\"]( URL_0 ) * Source: [Old batteries would have a limited number of recharge cycles -- \"with modern Li-ion batteries, you don't need to worry about performing shallow charges.\"]( URL_1 )",
"You charge a battery by forcing electricity through it backwards. So if you have a 12-volt car battery the alternater and charger and such can put up to 18 volts across the terminals. That extra 6 volts forces the electrons to go in the \"electrons come out here\" side of the battery. Batteries work through chemistry. You take some stuff (usually metal) and make a sandwich of the stuff around some other stuff (usually some acid or alkali). The middle stuff dissolves the metals releasing electrons and pushing them one way or another. So your car battery is a lead-acid battery, and your flashlight takes D-cells that used to be carbon/acid, but are now (something I don't remember)/alkaline. So that's what an \"alkaline battery\" is. So some batteries, like lead-acid, are easy to charge because the chemestry is really easy to reverse. Other batteries are just about impossible to charge because it's like trying to un-burn a log. This second type is the normal batteries and alkaline batteries you buy from the store. They just aren't _safely_ rechargeable. Why? They tend to catch fire and explode, or when you run the electricity through them backwards they don't produce the same chemicals they were built with. So we've always had the big rechargable lead/acid batteries. But making little ones has required a lot of development. There are different bad things things that can happen when you recharge a battery... For example the metal in the metal sandwich can fall apart from being repeatedly changed and changed back. This is why car batteries go bad. The lead flakes off and eventually the flakes form a conductor from the two sides of the sandwich and that fraction of the battery becomes useless. The typical 12 volt car battery has six sandwiches so when you lose a cell it's now a 10 volt battery. Lose another and it's an 8 volt battery and that's not enough to do the job. The battery can get hot and literally \"cook\". So the modern lithium-ion batteries have little thermostats in them and as you charge them they get warm, and the warmer they get the less electricity they can stand to take, so the thermostat slows down the charging by slowing down the current. That's part of why your \"quick charger\" for your phone will, on an empty battery, charge to 80% real fast and then take longer and longer to get to 100%. It got warm as fast as it got charged and so it can't charge to full without slowing down. Finally there's that whole thing where batteries \"get memory\". This is not what's happening. As you charge and discharge some kinds of batteries they get pits and cook into new chemicals \"fractionally\" So every time you recharged the old batteries you \"used up\" a little of teh metal or the acid/alkali. With some of the material used up, the total amount of available stuff to make electriciy was reduced and the batteries lost their \"capacity to hold a charge.\" People called this \"memory\" because it was easier. But in truth you were more likely to ruin a battery by \"topping it off\" than you were likely to ruin it by charging a nearly dead battery. So it _seemed_ like frequent short charges were \"remembered\". But, no.. So finally, what is over charging. Each sandwich inside any battery has a limit to how much electricity it can store. If you reach that limit and _persist_ in forcing electricity through it backwards then it _can't_ save any of that electricity as chemicals. So it _cooks_. Heat is generated and the good chemicals may bake or burn. For instance, as your car battery dies the headlights visibly dim. This is because the 12 volts becomes 11, then 10, then 9 (and so on) as you use up the stored energy. And as you charge the 9 become 10 then 11 and 12. (the actual peak number is something like 13 volts for a car battery, but let's stick with 12.) The charge/voltage regulator in your car stops charging the battery when the target 12 volts is reached because after that it's just doing damage. But if you've ever had a junker car that \"Eats Batteries\" you know it was really that your voltage regulator went bad. It wen't bad by being unable to stop the \"overcharging\". Now over time, because of different battery materials _and_ by the proliferation of _better_ electronics, the whole \"overcharging\" thing has largely gone away. We simply got better at the whole task from every angle. But we still hear of whole phones (by part number) that are \"prone to explode\". This happens when the phone in question, or the battery pack itself, has a design fault or was built with inferior parts. The bad design, or bad parts, lets the battery take in, or give out, too much electricity too fast. It gets hot. It get's unstable. And then it goes \"boom\". That's overcharging in a nutshell.",
"Modern device batteries have their own internal logic to control the input and the output of power. They come programmed with a safe range of charge and would not let you charge beyond an upper limit or discharge below a lower limit. Therefore you cannot overcharge your battery unless you're using a device from the 90's with those ancient nickel-cadmium chemistry. The worst enemy of your battery is heat. This is what slowly chips away its efficiency. Unfortunately heat is a byproduct of both charging and discharging process, therefore there isn't much you can do to improve your battery life (apart from not using it, that is)."
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5u7gvq | I grew up thinking that turning off your engine for a short stop only uses more fuel. How are the current start-stop functions a good idea if this is true? | Technology | explainlikeimfive | {
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"This is still true. Cars with automatic start-stop function won't stop again if the last start was not long enough ago."
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5u7vut | How does an artificial heart react when you get startled, or nervous or have sex? | I read an older article about a guy who had his heart removed and was walking around with a backpack machine acting as his heart. The question that occured to me last night while i was trying to see, was how does an artificial heart, which I presume regulates your blood flow at a set kind of pace, react compared to a person with a normal heart, which can suddenly start pumping faster or harder due to a reaction...being next to someone you like, getting scared, breathing heavy. Does it just keep pumping the blood at a normal set speed? I have to imagine that the organic and subconcious changes that occur when we encounter something based in fear or instinctual reactions cannot be duplicated in a machine, so if your breathing heavy due to a fright, how does the machine know to pump harder? | Technology | explainlikeimfive | {
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"> how does the machine know to pump harder? It doesn't. There are a lot of things you can't do when you're depending on mechanical assistance to keep your blood flowing. One of them is use too much oxygen. Because your new \"heart\" has one speed, and if you overdo it you're going to pass out."
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5u8iwu | How do seeds work in games? | I mean, how can a few numbers decide billions of things in a generated world? | Technology | explainlikeimfive | {
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"> I mean, how can a few numbers decide billions of things in a generated world? I'm going to give you not \"a few\" numbers, and not \"billions\" of things, but one number that can generate infinite things: 1. Start at 0. Add 1. Get 1. Add 1. Get 2. Add 1. Get 3. Add 1. Get 4. Keep going. Let's take a more complicated example, and limit it to a certain range of numbers (0 through 9), like the random numbers on a computer would be (0 through 2^64 - 1 or some such): Add 3 and then take the modulus 10. Start at 0. Plus 3 mod 10, get 3. Plus 3 mod 10, get 6. Plus 3 mod 10, get 9. Plus 3 mod 10, get 2. Then 5, then 8, then 1, then 4, then 7, then 0 again. Obviously those examples (even the \"more complicated\" one) are *much* less complicated than the algorithm that a random number generator is using. But I hope they suffice to show that there's no reason a small set of rules can't provide a large number of results."
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5u8was | If putting metal in the microwave is wrong then why is the inside of a microwave metal? | Technology | explainlikeimfive | {
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"When metal gets hit by microwaves, the microwaves bounce back. This makes metal a necessary component in keeping the microwaves inside the cooking appliance. However, the oscillating magnetic field of the magnetron (the device that's actually making the microwaves) can cause a charge to build up in the edges or tips of any weird-shaped metal objects, like forks or aluminum foil. These charge buildups naturally look for ways to dissipate, and do so with a dramatic (and hot!) arc. So the thing that really matters here is the shape. The big flat walls are fine."
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5ub32e | How do youtube resolutions work? If I choose 1080p and watch it at fullscreen it's showing at 1080p. But if I'm looking at it on the small player what resolution is it? | Technology | explainlikeimfive | {
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"Still 1080p, you monitor just scales it to be whatever size it is, think of a sponge, same amount of sponge but if you fold it in half and squish it to the same height you end up with it in a smaller space"
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5uca7y | Why do most modern helicopters have 4 or more blades, while most older helicopters have only 2? | Technology | explainlikeimfive | {
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"The Bell 230 and the 212 are mediums that have two blades. Both those were replaced by 4-bladed versions (the 430 and the 412). There are many factors that determine the number of blades. But in general, the trend you see in looking at the results of many development programs is this: smaller, cheaper, and slower helicopters have the fewest blades. Bigger, faster, and more expensive ones have more blades. Notice that the 412 (4 blades) has a max speed about 20 kt faster than the 212 (2 blades). In general you can say the following: For hover, low disk loading is most efficient. That means longer blades and therefore fewer blades. But for speed, more blades are better. The blades turn slower and the tip speed is slower, allowing higher airspeed before the advancing blade tips approach supersonic. This is illustrated by the 212/412 helicopters. -The 212 has two blades with a diameter of 48 feet and max weight of 11,200 lb. 100% rotor revs are 324 rpm. -The 412 has 4 blades with diameter 46 feet and max weight of 11,900 lb. 100% rotor speed is also 324 rpm. Disk loading 212 = 6.19 lb/ft^2 412 = 7.16 lb/ft^2 Tip Speed 212 = 813 ft/s 412 = 779 ft/s Vmax 212 = 120 kts 412 = 140 kts So the 212 has lower disk loading, it should perform better in hover (I don't have data on that). The 412 has lower tip speed and higher airspeed. Edit: re-wrote it with some numbers to illustrate.",
"First, that is not true. The first Sikorsky military helos in the US were a three blade design, while the popular civilian Bell 47 had two. The lift you get is based on the total length of the blades and their velocity. However, the more blades you have, the closer together they are, and the more they interfere. The most efficient configuration is 2 very long blades, but it takes up more space and it more demanding on the blades. Early helicopters were limited, because piston engines had poor weight to power ratios, leading to more 2 and 3 blade designs. Once turbine engines were introduced, they produced enough power per pound that more compact designs became feasible.",
"Several reasons: * Sound. Listen to the Bell 204/Bell 205 (the classic Vietnam helicopter). It has two blades, and it makes a very heavy, booming \"chop-chop-chop\" sound that is very rough on the ears. More rotor blades make a more \"brrrrrr\" sound. As helicopters are often used in urban areas, sound levels are a serious concern. For example, you don't want to plop down an ambulance heli at a hospital when it's makes the windows \"pump\" with the noise. * Rotor diameter. More blades means shorter blades. This means that it uses less space, which is useful in many situations. Edit: This also means a shorter tail boom is possible. For example, compare the Bell 205 with the Bo105 and look at how much shorter the tail boom is. * Speed 1. Longer blade will have higher tip velocity, and if the tip goes supersonic, bad things happen, which means that with longer blades, you need to have slower rotation, which means less efficiency. As the forward going blade is traveling at tip speed plus the forward speed, this limitation is the main limitation to the speed of the helicopter. * Speed 2. Longer blades will have higher tip velocity. On a helicopter, the forward going blade will always move faster than the one going backward, and the higher the tip velocity, the larger the difference. This means that you'll get more lift on the side where the blade moves forwards, and if you go too fast, this can become a problem. There are also advantages of fewer blades. * It's a simpler construction, which is important on cheap helis or if you really want to mass produce them. It also simplifies maintenance, which is important in some military situations. * Two blades takes less space in the hangar. * Rotor blades are expensive. Once again, a factor on cheap helis. The overall trend, on anything but the smallest helis, is towards more rotor blades.",
"Many modern helicopters still have 2 blades. At least in Canada. Small helicopters have 4 or 3 blades, but I've never personally seen a medium helicopter with more than 2 blades. Source: was a forest fire fighter and was around helicopters constantly",
"* more blades - > less vibration * more blades - > less power * less blades - > more vibration * less blades - > more power Given this, a broadly general statement suggests that since new choppers have more powerful engines, the next thing to do is make the ride more comfortable and reduce vibration."
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5ucr30 | How did a phone connect to another phone overseas pre-1950's? | Technology | explainlikeimfive | {
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"Major cities had a \"long distance switchboard\" which had access to overseas telecom lines (typically cables running under the ocean). You had to call the operator and ask for \"long distance\" and then talk the the \"long distance operator\" and tell them what country you wanted to call. They made the connection through very primitive means, sometimes literally by plugging a wire into a socket.",
"Underwater cables URL_3 It's still done for internet URL_2 This is what a modern submarine fiber optic cable looks like URL_1 edit: another cable map : URL_0",
"Everyone is talking about the cables, but a major difference between how information was transmitted in the 1950s and today is back then they used circuit switches and today we use packet switching. So in the 50s when you called someone, you got a dedicated end-to-end electrical circuit which meant that no one could use the line, or any part of the circuit, until it was opened. In the 60s, scientists developed packet switching, which broke data into tiny packets that could be sent across the line much faster and independently of each other. Fiber optic cables were dropped to make this process even faster.",
"The first international phone line was between key west and cuba. It's something like 90 miles. There's a tourist attraction there.",
"The same way we do today, cables in the Ocean. Regardless of public perception, your phone calls are not going to space over long distances. Especially cell phones. Cell phones go to the nearest tower, that's it, and then back to earth through cables. phone - > in the air to nearest tower - > cables - > nearest tower to person you are calling - > phone. Not once did it go to space or hit a satellite.",
"The first transatlantic telephone cable, [TAT-1]( URL_0 ), wasn't built until 1955. Before that, there were transatlantic telegraph cables, but they couldn't really carry a voice call. Before 1956, transatlantic telephone conversations were carried by radio on the HF bands. The HF bands (3-30Mhz) are a chunk of the radio frequency spectrum that can bounce off of the ionosphere, taking the signals much further than line of sight.",
"So during world war 2, it would have been possible to just call from the USA to a random phone in nazi Germany? Or did the trans Atlantic cables get severed during the war?",
"So, are these cables sitting on the bottom of the ocean? Or do they kinda float? Isn't the bottom of the ocean under so much pressure that the cables would collapse?",
"I've been to this museum. The first trans-Atlantic telegraph cable was connected here in 1866. URL_0",
"Transantlantic cables baby. We still use them today in fact. When a whale bumps into them it's a problem but they're able to repair them pretty fast."
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5uf3se | How does port forwarding help improve ping in online games? | If the games need port forwarding, wouldn't they just have no connection at all? I turned it on for my computer's IP address and my ping went from ~400 to around 30, but before then I could still establish a connection. | Technology | explainlikeimfive | {
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"Since you didn't say the exact game it's hard to say, but I would guess that the game has some sort of intermediary to help with that. So, without port forwarding you have: You < = > intermediary < = > other player While with it you have: You < = > other player If the intermediary happens to be on another continent or overloaded, that would have a very significant impact."
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5ufc0i | Why are iPads experiencing such a steep decline? | Proof: URL_0 | Technology | explainlikeimfive | {
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"That's just a search trends, not sales number, though it does suggest declinging interest in the platform. Here's some guesses **Market saturation** - everyone who's gonna get an iPad has one, and doesn't really feel like upgrading right now. **Larger mobile phones competing** - The size of the average mobile has gone up significantly, and for some people it might be enough screen real estate to not bother with an iPad. **Lack of innovation from apple** - this one is open to subjective interperetation. The iPad has not dramatically changed since it's introduction, they've simply made variants that are both bigger or smaller and thinner. While certainly impressive, they're not really enough leap forward for people to look at their current iPads and want to toss and replace 'em. **Shifting tablet market towards kids** - one of the biggest buyers of tablets are parents for young children: they're good entertainment devices. However, iPads are quite pricey, if you're going to get a kid a tablet they're going to use for learning games and YouTube For Kids... the low end Android units are serviceable and kids aren't going to care much, they'll just be happy to have their own device.",
"Because it's a durable good with multiple redundancies. Most people who would want an iPad already have an iPad. Those people probably also have a smartphone and a laptop, maybe a desktop computer and a game console or two, maybe a Roku, etc. Among all those devices, people would probably upgrade their phone first, their laptop second and everything else is a low priority. I've got a family of 4. Husband (me), wife and two young kids (4 and 1). We've currently got 9 devices. None are the most recent releases. I have an iPhone SE and a five year old MacBook Pro laptop, plus a PS4 and PS3 game consoles. My wife has a 3 year old iMac desktop, a recently purchased iPad Air 2 and a Roku. We keep an old iPad 2 and a near worthless Kindle Fire for the kids to use on long car rides. I upgrade my phone every 3-5 years. I'll buy a new game console when there are compelling games to play, but that's generally a 5-7 year span. We upgrade computers every 5-7 years, when necessary. We'll replace tablets when they become absolutely unusable, and even then we probably won't upgrade to the top of the line model. Tablets are great, but they don't require a whole lot of computing power or bleeding edge features. What do you use it for? Light web browsing on the couch. Cooking recipes in the kitchen. Playing videos for the kids in the car. Maybe a taking a photo or a video sometimes. Tasks that are convenient, but not crucial or resource intensive.",
"To answer this question, we should look at who are buying tablets. In 2011, 2012, 2013, the iPad was new. That means no one had one. So, the potential market is everyone. And perhaps families wanted to buy an ipad for mom, dad, brother, and sister. In 2014, most everyone that could afford an iPad and wanted one, probably has an iPad. What's the incentive to upgrade? Maybe GB if you're maxed out on your old iPad. If you have money just lying around, you might get a new one for its sleek new look or just to have the newest and coolest. Everyone else will just use what they've got. There are still going to be sales because kids turn 11 and want an iPad for Christmas. Or maybe you broke your old iPad and looking at the new ones. I personally have an iPad Air. It looks like that came out in 2014. I'm perfectly happy with it. There's no reason for me to upgrade."
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5ufvky | How are video games created from the ground up starting with nothing? | I realize you need to code the game but I don't understand how they incorporate all the actual models for the environment and character models. I also would like to know what specific language of code is used in making these games. Java, Python, C++, etc. For triple A games, do they have specific teams working on different parts of the game? if there are, what are the names and purposes of these groups? | Technology | explainlikeimfive | {
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"Former game developer here, Rare does a AAA title build from scratch, typically they'll use pre-existing engines, leaving the hard work to the pros. Also, engines are part of a games branding. Assets, being your models and textures for the purpose of this ELI5, are created in editors, and saved to some project file for that editor. These file are HUGE, and contain all sorts of meta-data appropriate for the editor. Typically, the undo stack is saved with these files. You don't need any of that for a game, so the contents are \"exported\" to a stripped down format. Exporters exist as plugins for popular editors and are often bundled with or available for popular game engines, but studios can also write their own. These exported files, at minimum, will contain a list of all the 3D points in the model as an array, and then a list of polygons indexing that array. An array is an indexed sequence, where the index number is implied by the position in the array. Programmers count from 0, so if you have your data structured like so: points = {[11.2356, 4873.234, 858.2838], [973.22, 1.53, 68.333], [...], ...} Then here I have point 0, point 1, and so on. Each point has an X, Y, and Z coordinate. Each point is unique, you don't have to list it twice. And from the list of points, you can specify your polygons by a list of 3 point indices: polys = {[1, 2, 3], [1, 2, 4], [2, 3, 5], ...} Notice that the triangles all share two points, meaning these triangles are sharing edges, they butt up against one another. If you were to draw 3 triangles, each sharing one edge, and you labeled the corners by these indices, you'll notice another property, the way the indices are listed, and they way you have to draw them together, the indices are all in a clockwise fashion around the triangle. This is called the right-hand rule and is how back-face culling works. If from the cameras perspective the indices are counter-clockwise, you're looking at the back side, and it should not be rendered. Also, poly strips and fans are very efficient, there are ways to minimize the number of indices you have to list, which I didn't demonstrate here, but you would list the first 3 indices for the first polygon, then the last two are assumed, so the 4th index is the 3rd point of the next triangle, and so on. There may also be a list of 3D vectors, just like the points above, but they're not coordinates in 3D space, they represent a direction, and the length from the origin ([0, 0, 0]) to the coordinates specified, this is called the *magnitude* of the vector, is 1. These *unit vectors* are also called *normal vectors*, and there may be one per polygon, or one per each corner of a polygon. These vectors are used in lighting equations, the core equations behind coloring each pixel. There may also be a list of texture files and a set of 2D \"UV\" coordinates, which are used to map a texture file over the polygons of a model. Texture files can be a single image, or they can be a large, square image with multiple instances of the same texture, just at different scales, for mip-mapping, as the model moves closer to the camera it will use a different scale of the texture to maintain visual quality without pixelated render artifacts from stretching or shrinking the texture. There can also be a \"normal map\" which is often stored as a very pinkish purplish BMP for convenience, that the data of the image are actually normal vectors for each pixel in the texture. The color is a mere consequence of interpreting the data as an actual picture. This is used for things like bump mapping. These files may contain a list of individual models, a hand, a forearm, an upper arm, a shoulder, a torso... Or it may contain a single model and sub sections may map to groupings. So there may be a matrix, a 2D grid of 4x4 numbers, for each model, and then more information describing the hierarchy from some center point of the model to the end of all it's extremities. Matrices are used to transform points from here in model space, to world space in the game, to screen space represented by the \"camera\". Any part of the model that can move independently of any other part has it's own matrix, and the points are multiplied by matrices down the hierarchy, any matrix that changes higher in the hierarchy requires all matrices and points in all the models to also be re-multiplied. The file may also contain some bits about animation sequences, equations how to *interpolate* the model from one point to another following a curve, constrains in motion, and all sorts of other meta-data having to do with queued sequences and sound effects, all embedded in this file. The editor has to support adding arbitrary meta-data to the model for export, or perhaps there's going to be another, intermediate tool for adding that, or perhaps it's stored in a separate file. These exporters can typically export in two formats, a human readable format, perhaps JSON or XML, and a binary format native to the engine. Computers don't care about brackets and spaces. --- Most games are written in C or C++. There are better languages out there, but the industry is full of C++ expertise and has a solid foundation written in it. You don't just abandon code, writing from complete scratch is expensive. The engine is going to have some sort of file parser that knows how to read the model files and transform the raw data into memory buffers. There will be different teams, but their role and purpose are quite varied. Typically you'll have gameplay developers who focus on things like how the menus work, how jumping and climbing works, user input, etc. You'll also have highly skilled developers who focus on custom physics and rendering in one of the shader languages. Lots of these engines support embedded scripting languages to decrease turn around time and designers tend to know scripting languages. So Python, ECMAScript (aka Javascript), and LUAScript are not uncommon."
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5uggi0 | Before alarm clocks, how did people regulate their sleep schedule and wake up at different times? | Let's say a king wanted to have meeting at 7am back in the 1400s. How did people wake up at a precise time to make it to that meeting? | Technology | explainlikeimfive | {
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"> Let's say a king wanted to have meeting at 7am back in the 1400s. They didn't, because they didn't schedule like that. They would say \"an early meeting at daybreak\" and then the king would start the meeting at this convenience.",
"Clocks were rare and inaccurate in 1400, so there wouldn't be a 7am meeting. More likely there would be a meeting at dawn or breakfast. Meals were kind of a big deal then, being in the service to a noble meant you got to eat with his household. A lot of affairs revolved around the meal schedule. Alternatively, the king would send pages out to say \"you have been summoned\". Over the next hour or two, people would arrive and wait until the king was ready for them. Also, if you were important enough to meet with the king, you probably had servants who had to get up early anyway and could tell them when you wanted to be roused. While this came later than the 1400s, there was actually a job called a \"knocker-up\". It was kind of a subscription service, a bunch of people would pay them a little, and they would come round each morning and wake you up at the proper time.",
"Very early on there were some pretty cool inventions substituting alarm clocks. In the far East, can't remember exactly where, some people had a model boat with an incense stick down the middle, marked for each hour or certain period of time. They then attached silk or string to a certain point on the incense stick with a small metal weight on it and a gong underneath. Say they wanted to sleep for seven hours exactly, they'd put the weight on the seventh mark, set the stick burning and after 7 hours the weight would drop. I don't know exactly if they used hours. The boats were shaped like dragons too and about 2 feet long, I assume they were pretty expensive. I saw it at the V & A museum, pretty neat, but there were other alarm clock substitutes which I can't remember now, mostly involving fire of some kind burning slowly. Also in Victorian-ish England they had people who were paid to go round knocking on windows with a long pole at certain houses and at certain times. There's another one.",
"How would the \"knocker up\" wake up to be able to do their job?",
"Someone can probably bring a reliable source, but I remember reading a book that people would place a piece of metal a certain length into a candle, then hang it so the metal would hit a bell or something when the wax melted far enough. Other than that, most people regulated via the sun. A lot of people would sleep at the onset of night because, no light yo, then sun would wake them up. People would then create a schedule based on the sun. \"Go farm shit when the sun rises.\" \"Chill out under a tree at noon when sun is highest in sky\" \"Go home and eat rabbit stew at dusk\"",
"I know one of comments I read before said Indians use to drink a cup of water before bed so that way they have to wake up and pee. (two cups if you want to wake up earlier) Thought that was pretty neat. It works too."
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5uk349 | How do hackers hack a web cam? | And is it possible for them to record without the indicator light turning on? EDIT: specifically a laptop's built-in webcam - if that makes a difference... | Technology | explainlikeimfive | {
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"> How do hackers hack a web cam? Bugs. A lot of software is insecure. Not all. A standalone webcamera is an \"Internet of Things\" device. Oh god, there are so many poorly secured IoT devices. > And is it possible for them to record without the indicator light turning on? Depends. If the light is hardwired to the power of the camera, no. But other devices, like [logitech cameras]( URL_0 ) or [macbooks]( URL_1 ) don't even need the firmware flashed. So, that's a solid yes. > specifically a laptop's built-in webcam - if that makes a difference... As a device that's part of a real laptop, with a real OS, then it's probably more secure. But on the flip side, OS's do a lot more stuff which are more vectors for an attack."
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5uks3a | How does an API work? | Technology | explainlikeimfive | {
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"It allows applications to use components of other existing applications with relative ease. For example, Google Maps is an application. The Google Maps API (Application Programming Interface) allows other applications or websites to pass commands to Google Maps application. So you could have a website that searches for businesses then shows you a local Google map and then sends commands to the map to flag/highlight that business. It's like 'hey I'm a great program and here the commands that your program can send to me'",
"If I have a company that monitors how much Halloween candy people get, I can collect that number, save it to a computer in database, and make a website that shows everyone who wants to see that number. URL_0 Let's say I have a friend that wants to know how much candy people get on Halloween and Easter. He'll count Easter candy, but he doesn't want to go to my website each time and search for the number for Halloween each time by himself. I can create an API that gives him that number. As long as he tells the computer which year, he'll get the number of Halloween candy back. URL_0 /2016 So an Application Programming Interface is a way to talk with a computer program across the Internet most likely to see its database."
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5ulgk5 | What could happen if the internet is not 'neutral'? | Explain the potential ramifications in a world without net neutrality. | Technology | explainlikeimfive | {
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"/u/tsuuga has done a decent summary. I'd like to explain it in a little more detail: With net neutrality in place, your ISP is obliged to provide you with an internet connection, the speed of which is determined by how much you pay for that service. And no matter which website you go to, the speed at which you receive the data (load the website, stream the audio or video) will be the same. Without net neutrality, the ISP is free to decide at which speeds you're going to be receiving data from various sites. For example, your ISP might decide that it doesn't want youtube videos to load so quickly, because reasons, They might say \"Well our infrastructure can't handle video data at that amount. Yes we can upgrade, but it will cost more money. Youtube can pay us an amount and we'll make sure their data goes through smoothly. And they can extend the same kind of deal to anyone. With diffrent prices. Seems fair so far right? Well not entirely, a lot of ISP's have other interests as well. For example, in the US Time Warner has it's own video streaming service. And Netflix has one as well. In this case it's a very good idea for TW to throttle the bandwith of Netflix to a point where it's no longer possible for you to watch Netflix. But their own streaming service will work like a dream. So it gives ISP's unfair oppertunities to stop competitors from doing business. And the same thing could happen for other things as well. Perhaps removing/restricting access to websites which go against the interests of the company. IE you can't see the site for a competing ISP because well, that's competition. You can't go to the site for political party X because they're going to try and push through legislation that the ISP doesn't like.",
"Internet service providers could charge you, companies or both higher fees to retain the same service and they also gain the ability to censor as they see fit as they could simply strange connections to websites they don't want to have traffic. Internet access could become more subscription based. You'd have your 'base internet' access, but for only $19,99 you could subscribe to the Social Media Package™ and have unrestricted access to Twitter, Facebook etc. Alternatively those sites would pay the ISP to give users access to their websites. If you like videos, for an additional fee you could also subscribe to the YouTube Package™ - you get the idea.",
"Right now, ISPs have to treat all data the same. If neutrality goes away, your ISP could take bribes from a company like best buy and make their website run faster. Meanwhile, Jim Smith, the owner of jim's electronics, is unable to afford to bribe the ISP, so his website takes 5 minutes to load and all his customers get pissed off. Jim's customers buy things from the best buy website and Jim goes out of business because he couldnt afford to be extorted by comcast.",
"Your internet bill would at least double for the same alleged level of service (though the price increase would be split up and added to website subscription costs, rather than billed to your directly). Your connection to many sites would be slower. Streaming video sites not owned by your ISP would run like crap, because they compete with cable TV and your ISP's streaming video site.",
"I pay for internet service. That service is a certain speed and may include a data cap (or not). For my payment I am entitled to \"equal\" access to the entire internet. My internet provider is NOT entitled to give priority to certain traffic over others. This is a world with a neutral internet. The ISP's network is natural to the traffic it carries, it does not give priority to some over others, it simply gives me exactly what I requested at the maximum speed it is able. In a world without a natural ISP, the internet provider (for example, Virizon, Comcast, Time Warner ect) is able to give priority to certain traffic over others. At first, that seems OK, but once we start looking at it in pratice things look much darker. What the ISPs want, is the ability to charge the company that you are connecting to for the right for a good connection. So in addition to charging you for internet service, they'll be charging companies like Youtube, Netflix, Facebook and so on so that those companies can access the highest speeds. Keep in mind, these companies are already paying their own ISP for their internet access. But now they would also be paying your ISP for special access to you. This is particularly important for HD video content as it uses lots of bandwidth for good quality. Any website that does not have a special deal with your ISP, would be delivered at a slower service. This again seems kind of fine, but kind of not. Where it really falls apart is in the world of innovation. It was not that long ago when streaming video games was just not really a thing people did. Then along came twitch (and others) and the popularity exploded. Not streaming games is extremely popular. In a world of a not natural internet a start up like Twitch could never have survived. It pays for it's own internet access. You pay for your internet access. But baby Twitch can't afford these extra fees to every ISP in America, so they are on the \"general access\" network. But they don't have enough bandwidth to deliver HD content over that network, so everything is pixilitaed and of poor quality. Some users use it anyway, other's don't because the service is so poor. In a natural intent, the users would choose to use the bandwidth they've paid for to stream from Twitch at the highest quality possible. In a non natural world, Twitch would have to pay for that privilege and the users would not be the wiser. It gets even more nasty. Netflix is a BIG competitor to your cable company. For most users, their cable company is also their internet provider. In a non natural world, the cable company could tell Netflix \"OK, no more HD streaming for you, we're just not going to allow that\". Then turn right around and offer their own streaming service that DOES stream in HD. So if you want HD streaming you'll be forced to buy it from the cable company. You already see a little of this in the Cell Phone world. AT & T owns Direct TV. If you subscribe to Direct TV now (Direct TV's streaming service) and use it on your AT & T cell phone, it does not count against your data. If you use Netflix, it does. So if you have to choose what streaming service to subscribe to, you'll chose the one that you can actually use while on mobile data.",
"Basic point: Your service provider will have control on what you do online. How is this bad: You already know this, but for speculation and prospective purposes, but basically it can (and will) be corrupted for political/financial agendas. E.G. Your ISP leans to the right, I mean FAR right like Breitbart right. Your ISP has the right/capability to basically prevent you from accessing any news site that isn't far-right or Breitbart. You like streaming movies on Netflix. Your ISP happens to have a deal with Time Warner Cable. Your ISP prevents videos from Netflix, Youtube, or any other service that loads videos from working on your computer. The only time you can stream is content from TWC because your ISP controls what data and how much you have."
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5ulx0o | Can someone please explain what a quantum computer is and how its the future of computing? | I heard a scientist on the radio yesterday who was asked to explain what a quantum computer was. After listening to him I was more confused then when he started. Him - "current computers are a bunch of ones and zeros" (???? what) Him - "Quantum physics cant be measured or followed the way a thrown baseball is" WTF does that even mean? How does that explain what a quantum computer does and how it is different then a normal computer? | Technology | explainlikeimfive | {
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"Okay. So the way current computers work is that they use electricity to process information. Modern computers only use 2 states. Either no electricity is flowing (0) or there is electricity (1). This might sound complicated but it's pretty easy. Think of a lamp. If you turn the switch off no current is flowing and the lamp is off. This represents a 0. Vica versa, opening the switch allows current to flow and the lamp turns on. This would be a 1. You can use these 1's and 0's to do simple logic. For example, imagine a lamp with 2 switches along the cord. The lamp will only turn on when both switches are closed. This represents a logical AND gate. Swap the switches for electronic transistors and this is all your computer is doing. You can combine logic gates to make a circuit that can [add binary numbers together]( URL_0 ), or a [bit of memory]( URL_4 ), or a control unit. With a complicated enough set of logic gates you can do all sorts of math, render video or browse reddit. We've gotten quite good at making those complicated circuits. But we're starting to hit some issues. For example, it is getting hard to cool those circuits so they don't break themselves. We're also hitting other, more fundamental limits related to the size of these transistors (Can't make a circuit out of half an atom....). So a lot of people are trying to figure out new ways of making better computers. Quantum computers work on the principles of quantum mechanics. The universe behaves weird at the very small scale. Particles act as waves and vica versa. For example: If you take a barn door, cut 2 holes in it, and then shoot bullets at it, you'd expect [this pattern on the far wall]( URL_2 ). However, if you take a tiny double slit and fire single electrons at it, [this is the resulting pattern...]( URL_3 ). We think it does that because every particle has a 'probability wave' that decides how likely it is to hit any specific spot. When you have 2 small holes the [probability waves interact]( URL_1 ) to produce that pattern. The electron is more likely to hit the place where the probability waves amplified themselves, and less likely to hit the spot where they cancelled out. Therefore producing that weird pattern. Quantum computing is an attempt to exploit this trick. There are a few problems that are hard to solve using normal computers. For example, figuring out by what primes a number can be divided. The only way to do this with conventional computers is to check every single prime, which takes a bloody long time if the number you're dividing is big. A quantum computer tries to solve that problem by making probability waves interact so that correct answers are amplified and false answers are negated. To give an example. That interference pattern for the double slit experiment is essentially the quantum mechanical answer to the problem \"Find all the points on the screen where the absolute distance between the point and either slit differs by n wavelengths\". Obviously this isn't a very useful problem to solve, but you can theoretically translate many problems into a quantum mechanical interference pattern. If we get it working correctly you could add a \"quantum computing card\" to your computer to solve those problems extremely quickly. The same way you add a graphics card to quickly render video."
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5ulxyx | How do companies like RedHat and Canonical make money / remain in business? | Technology | explainlikeimfive | {
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"The big money in software is not directly in licensing but in support. Most software products bundle these together in some way. However RedHat and Canonical do not take any money for the development of their product but rather takes money on support. Imagine you are the CTO of a big bank. Your company make a lot of money but you also have a lot of unique requirements for your IT infrastructure. You might want to be able to verify that the software you run are correct and that there are no back doors. You might want the ability to adapt the software to your needs and have full control over that process. So you want an open source system so you are free to look at and modify the code. However you want someone to fix the problems you have at 2am that stops the business and lose you money. And who knows how your operating system works better then the people who put it together and developed big parts of it? So you pay RedHat or Canonical support fees so you can call them up at strange times and have experts fix your problems."
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Subsets and Splits