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m47ki8 | Where does crypto get its value? | Technology | explainlikeimfive | {
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"Stocks don't give us products. 99% of the time you are buying the stock from someone else and no money goes to the company. The only reason why crypto had value is because people want it. Like gold, it's not really useful, but we give it value and use it as a currency. They do have some privacy and other benefits as opposed to other currencies, but I don't think that's what you're asking.",
"I mean, what we call money isn't that valuable either. It's just paper with stuff printed on it, and metal coins. That metal isn't even valuable like gold. We as a society agree to act like it has value and it can be traded as such. Crypto-currency is a concept for an alternative form of money - one entirely online, without a controlling government, and with a good deal of transparency - that took off in popularity. Mining is actually a necessary part of how the process works and needed to make bitcoin function at all, so miners are rewarded for their efforts with small bitcoin payouts periodically. I don't think anyone expected the value of a bitcoin to get so high. If you believe something has value and you want more of it, and everyone around you believe something has value and want more of it, and there's only so much of it to go around... Then that's enough for it to have value, isn't it?"
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m4asqb | How does a game like RDR2 spend 7+ years in development and release with such advanced graphics technology | When they started writing game code ~7 years ago didn’t they need to lock themselves into an engine? And wouldn’t that game engine be outdated visually by the time they release the game? | Technology | explainlikeimfive | {
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"game devs often interact with hardware devs and have access to development kits, with features not yet available to the public [projects have tanked because of poor communication/choices between devs and the hardware folks]( URL_0 ) > Timing and industry changes turned to trouble for Prey. It was mostly developed on the 3DFX card and the Glide API (\"It was the hot shit API of the day,\" Schuytema says) but internal troubles at 3DFX hit just as the Prey team was ready to go all-in with Glide. Meanwhile, Microsoft was getting its Direct X API off the ground. The team moved away from Glide, and ended up going with Direct X instead.",
"They lock themselves into an engine API, but they don't spend 7 years working with the same version. Every few months, they baseline a better version of the game. Sometimes that version just has more \"game\" in it and sometimes it has migrated to a better version of the engine. It's not a 7-year straight line, that wouldn't have likely been funded. Rather it's an iterative process that just took 40-ish iterations to get a game that was great enough to release.",
"The great thing about using game engines in the first place to make games, is that it keeps the \"data,\" and the \"engine,\" pretty separate. This means you can have one group working on making models, textures, level scripting, etc. and another team can work on improving the engine and keeping up with modern tech. As long as the team working on the engine don't change the way the engine reads data, then it will just load in the same data the way it always has, just with better graphics or whatever. Only if there is a breaking change would things have to be re-done. This is also a big reason (not the only reason though) why we see \"fake,\" E3 trailers and such. When a game is announced really early, they are running on a PC that's light-years ahead of current tech, using models and maps that would never run on a modern system, simply because that's where the devs *think* tech will be in 7+ years. Sometimes they get this wrong and have to scale back ~~-------------------------------------------~~ **EDIT:** I'm getting the same questions a lot about the \"fake,\" E3 trailers and such, so I'll post the answers here: * It happens * Game devs aren't stupid. They know nobody looks good when the released game doesn't live up to the hype. * Devs that have a more corporate structure are more susceptible to this, as they have to pitch games to more \"business types,\" who don't understand how games are developed and it's more effective to show flashy graphics than 15 power-point pages explaining your revolutionary game-mechanic or technology. Same deal when you're making an E3 trailer. * Games that fall into the \"cross-gen,\" release window are especially susceptible to this as you are targeting still-in-development hardware which you want to push to it's limits, but those limits are frequently changing. You guess at what you think you'll be able to get running, and then you cross your fingers hoping you actually can by launch. * There *is* a level of responsibility of the devs to communicate early on that the game is changing, however game development is so incredibly turbulent that it's difficult to even know when to cut your losses. The general audience also needs to understand that features are cut because they don't work out, things change, that's development. * The situation with CDPR was the perfect storm of failures in PR and management, combined with the points above that it failed so spectacularly and ended up an outlier and an edge-case. I would really recommend everyone who is interested in game-dev to give yourself a 2-month limit and make a small game. It's extremely fun and rewarding, but it will really shatter your understanding of what actually goes into making one of these things.",
"I'm stoned right now and had to read the title five times as I couldn't understand why R2D2 was a game...",
"In short: Once everything is laid out for a game, not many things change during the development, other than the more detailed assets and lighting is added.- but that depends on hardware capabilities in order to render a number of things on the screen. More computing power- > more things can be rendered on the screen- > more detailed assets in the game- > nicer graphics. Sometimes placeholder dummy test assets are used in order to start with the development and start working on other fields such as mechanics, combat, quest, story etc. Then later on these will be changed with high def, nice 3d model. Think of the years between the start of the game development and the end of game development as the weather conditions. And think of the game assets as clothing items. Imagine as if you are going out for a job interview. You carefully plan everything before going there. You leave the pet at a friends place, you make sure that you know what to say during the interview, you go over some questions that they might ask you, you prepare your resume, you look for the company details, policy, salary, you practice speaking in front of the mirror.. then the only thing what's left is - to choose what you gonna wear for the interview. Let's say that interview was scheduled for January, during that time it rained hard for days. You prepared what you gonna wear, obviously something warm, a raincoat is a must and waterproof makeup probably if you were a girl. - for that weather at the time that was the best obvious choice of clothing. \\- then suddenly the interview was postponed for next week.. But next week the weather is totally different, its quite hot, no rain in sight...so obviously you had to change things around...(you don't need a raincoat, no need for warm clothes..etc) this time though, you didn't have to plan and prepare anything as you already finished that part beforehand, all you had to do is to change your clothes to suit that day's weather. The same goes for the games, once the foundation is laid out, things change, but they are much more straightforward to change than to plan everything from scratch. & #x200B; Each game consists of many different components. To simplify it we gonna assume there are only these for now: \\-Characters - (3D models of the character, textures/UVs, materials, their voice lines, rigs, and animations.) \\-Environment - Assets such as foliage, buildings, objects... Post-process effects and lighting - Fog, lights, clouds, ambient effects, shadows, scattering... \\-Game mechanics \\-Story \\-Cutscenes Most of the things wouldn't make any difference if they were made 7 years ago or today. \\-For example, when low poly characters are created, you can rig them, make animations for them, do the voice lines, combat system, controls. The same goes for level design, when assets are created (Buildings, props, foliage, terrain...), you can texture them and place them into an appealing composition that makes the level- well level! \\- Assuming that the programing part is finished, combat system, animation blends, controls, quests, there is really not much left to do, other than cutscenes-but those are usually done with really high poly, very detailed assets/models cause they don't have to be rendered in real-time, and you can add effects in post-production using video editing software. Once you have these laid out, you pretty much have a complete game. Most of these things don't even need to change from that point other than fixing bugs and some incompatibility issues due to the different engine version advancements. The only thing that really changes over the years is the polycount of the character/ assets that can be drow on screen, and lighting post-process calculations can change from time to time.- those dependable on the computing power. With each new generation of GPU-s they move this slider further up, so the polycount of the model increases, and thus looks more detailed. They also add new things that can trick you into thinking there is geometry where actually there isn't any. So for example let's say that in order to render some game in 2016 at 1080p with 60-fps, the max polycount used by the assets on the screen is 10 million. Fast forward to 2021, we could probably render 50 million or more..So this thing allows devs to create more detailed characters, swap them with the old ones created in 2016, while keeping their animations, voice lines, mechanics...etc.",
"It's easy to forget, but a game that released a year ago may have started development even before RDR2 did, so in a way we're seeing today the results of industry trends 5+ years ago in games releasing now. Beyond that, major game releases like this tend to communicate their needs to Nvidia and AMD, and those GPU companies take that information and will often tailor their upcoming GPU architectures to suit various industry trends, within reason, of course.",
"Follow up eli5: How was RDR2 so drastically better than cyberpunk despite less development time and developed like 3 years sooner?",
"Yes they lock themselves into an engine. But engines limits are years ahead of what consumer hardware can handle. If they could magically finish that game in 1 day it would be able to work like now, but noone would own a computer to actually play it without lags. Also the graphic optimization is a pretty late process in the developement. And the engines can be patched with new features too.",
"Most of the time, these are the games that set the new standard. That's why it take so long, because they are creating new features...new ways. Then they can fine tune it to the most advanced graphics before release.",
"The engine is not as important as some people think. Some game engines may make decisions that are difficult to change without a lot of work. But it can always be done. Many game engines used today have started from a codebase that was originally made for the first Quake games. They are being upgraded to this day, even if they have received new marketing names.",
"> And wouldn’t that game engine be outdated visually by the time they release the game? Most, All? of these answers are very off base. Game engines aren't some monolithic unchangeable black box. They're a collection of tools that render graphics, handle physics , sound, scripting, the AI, on and on. Those tools are more or less independent, and are often designed to be modular. If you want to improve the physics, you can do so without throwing out the entire engine. For that matter it's often possible to integrate someone else's tools, or ones you've built in house, with that engine. Want to add better fluid simulation at a later date cause there's some new techniques available now? You can probably just do that. Want to include higher res textures? The rendering engine doesn't really care how high res the textures are, you can change that pretty much arbitrarily. Better lighting effects? All you're doing is messing with the tools that handle lighting. The game world doesn't care *how* it's lit, and all the light sources don't care or know how they light things up. Project management is also key. If you know your going to spend half a decade developing the game, you can anticipate improvements in tech. So you can move features that rely on it till later in the devlopment cycle, while focusing on parts of the game where you expect things to be more static. Rockstar is a good example there because they use their own engine. GTA4 and RDR2 are built on the same engine. They've just updated it as they went along. for Red Dead Redemption 2 one of the big changes was pre-calculated global illumination and it's entirely possible that wasn't a finalized feature till the last year or two of the games development. Being 'locked in' to an engine is not terribly restrictive. Just like anywhere else, a toolset that limits your ability to do and change things is a bad one.",
"Lets say you tell me to draw a triangle. Specifically you say “draw a triangle”, and I draw triangle. Today, it takes me 3 seconds to draw a triangle. Now lets fast forward a couple of years. I’ve gotten really good at drawing triangles. Now, it only takes me 0.5 seconds to draw a triangle. However, the way you ask me to draw a triangle hasn’t changed. When you say “draw a triangle” I draw a triangle just as before, only faster. Now imagine you ask me to draw a thousand triangles. At 3 seconds a triangle, that would take me 3,000 seconds. But if I said to you; Give me a couple of months and I reckon I could draw a triangle in 0.5 seconds, then you could plan for a future where asking me to draw a thousand triangles takes a mere 500 seconds instead of 3,000. Also, the way you ask me to draw a triangle doesn’t have to change. You could write a letter asking me to draw a thousand triangles, and it wouldn’t matter if received that letter today, or in a years time. The only difference would be how quickly I drew those triangles. Thats how programming works. The instructions stay the same, but the way those instructions are executed can change. When you ask me to draw a triangle, you don’t care how I draw it. All you care about is wether or not you get a triangle. If I tell you that I’m sure I can figure out a faster way to draw triangles, then you can plan ahead for a future in which you can ask for more triangles in a given amount of time. Thats how game engines work. Game engines draw triangles. The faster a game engine can draw a triangle, the more triangles it can draw in a given frame, and the better the graphics are. When a game engine draws a triangle, it has to compute all kinds of things like textures and lighting for every single triangle in every single frame. The people making the game just ask the engine to draw as many triangles as possible.",
"Actually most advanced graphics techniques are based on existing algorithms, some as old as the 1970's or 80's, it's just that the math involved is extremely processor intensive to do in real-time. As processing power increases the can run more of these calculations in real-time.",
"It... didn't? Raytracing was the current 'cool new tech' when they released and they don't have it. High Dynamic Range had been around for a while but was still 'current' when it released and they couldn't get it to work correctly until a few patches later.",
"They're very familiar with the hardware they're writing the game for, and they design the game around looking as good as possible on that hardware. And because they've been working with it for so long, they know every trick in the book. Everything about the game - from the lines of sight on the map to how story missions are structured - is designed to make the graphics look as great as possible, given the limits of how quickly the console can load and process stuff. (If you were given the ability to drive around really fast in a car, or fly above everything in a plane - like in GTA5 - things probably wouldn't look as good.) They also put a ton of money into art direction - a game designed by talented people is going to look far better than one made by amateurs, regardless of resolution and shaders and what have you. RDR2 looks the way it does in large part because it was made by very skilled artists, not because of \"advanced graphics technology.\" The actual resolution RDR2 runs at on stock consoles is nothing special, but lots of smart people spent years making sure the flaws show as little as possible. (That's also why the PC ports of Rockstar games don't blow people away nearly as much, when compared to games designed from the ground up to look great on the PC - or the PC and consoles - and why they don't run very well on low or mid-level PCs, even though those are technically more powerful than the consoles.)",
"At any given point in time, the graphics we *can* create, period, are way beyond what the average consumer has in the way of hardware. The graphics you will see in games many years from now *could* be made now if everyone had the hardware to push it."
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m4hqgy | Why do Webpages on mobile devices especially still jump around frequently while loading? It goes as far as you cannot reliably trust what you about to hit will be still there when hitting it. Can't there be a load order that prevents that? | Technology | explainlikeimfive | {
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"Scripts load at various times, often triggered by other scripts and elements on the page. Also, many images are not properly coded with width/height info causing the image load to make the page fluctuate. A fun way to learn about how the web really works is to use an add-on like noscript. You will have the base page load (html) and each script in the page will need you to manually turn them on one-by-one. Well, you don't HAVE to, there is an \"allow all scripts on the page\" button. Some pages only have one or two script approvals required. Journalism/media sites will have so many you will need to approve them all, then approve the scripts those scripts loaded. Possibly multiple times. As the scripts load, you can watch the content on the page jump around as they load in. That's what is happening normally every time you load that page, just mostly all at once.",
"There's a few possible reasons. Many web sites, and especially mobile pages (which still baffles me) are built client side by scripts. So the slower CPU in phones may lag that a bit. Pictures are downloaded separately from the page itself so there is a delay while the browser figures out what it's building and adjusts as it learns more. And of course, so many pages are designed to detect the screen size and adjust their own layout. That may be delayed and cause the page to be redrawn with the new layout to accommodate the new size as the script kicks in and realize what's going on. Of course, there are other possibilities and I can only speculate without actually seeing the site in question. In my opinion, what's considered modern and \"the way to do things\" on the web today is dumb and responsible for these annoying browser behaviours. You can design a page that loads properly the first time and doesn't do this, but the web designers have to change how they make web sites and give up that automatic adaptation to the screen resolution. Geez, web pages are more complex than some actual PC and phone apps."
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m4j6b2 | why are plastic chocolate bar wraps so hard to tear apart when they have a smooth normal edge, but so easy to tear apart when they have a little dent on the side? | Technology | explainlikeimfive | {
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"If you pull apart two ridges of the dented area **all** the force from you pulling is concentrated in a single point, where the two edges meet, allows the material to rip. If you're pulling apart a smooth piece the force gets evently distributed between your fingers."
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m4jlxw | Why are there auto-playing videos on so many websites? | Technology | explainlikeimfive | {
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"10 seconds of content to get to 2 minutes worth of unskippable ads. They gotta pay the bills somehow, after all."
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m4qqg6 | Why do video game graphics usually allow body parts to move through walls, capes to pass through your body, etc? | This is perhaps the most common, most visible, and most enduring "unrealistic" part of video games. For example, when your character is killed and they fall to the ground and their arm just flops through the nearby wall/barrel/person. Similarly, sheathing swords or wearing draped clothing usually results in your legs/elbows passing through the clothes when you run, etc. Obviously the devs would fix this if it were feasible. Does it just take too much processing power? | Technology | explainlikeimfive | {
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"Yeah, it's a computational limitation. Flexible shapes mean expensive collision-detection/physics, and most games would rather invest their computational power elsewhere.",
"So, generally entityes have a \"hitbox\", which is like the collision of the thing. But the graphics are much more complicated than a box, so some parts of the thing are not solid (what I mean by that is that if they touch something, it doesn't matter). This also explains why sometimes something may hit you, even though it looks to just barely miss you.",
"Doing collision detection and physics takes a lot of processing power. It's technically possible, but you'd need a really high-end machine to do it well in real time on all the objects in a game. Using canned animations and positions is a lot easier.",
"3D graphics are composed of triangles and the triangles are *ghostly* by nature. Collision detection and physics all have to be explicitly programmed in. The graphics card and engine do some degree of automatic culling but it's usually just removing offscreen triangles and triangles behind other triangles. You COULD program it so your arm moves away or turns invisible if it passes through your cape so it looks more realistic but why do that when no one does and that time would probably be better spent adding new content? There were NES era games with pixel perfect collisions instead of simple hit boxes but the players didn't care and those games didn't take off. Metal Blade and Spindash were more fun even though the collision wasn't pixel perfect.",
"Because graphics are just graphics. They don't have any \"mass\" to them. You have to explicitly tell the computer what bits can collide with what bits and how the graphics change. The more detailed your collision checking it the more processing power you have to dedicate to checking it. Generally you won't have a collision check for every triangle on screen: there can be billions of them and that would take forever. What happens is that usually the collision is just a series of boxes loosely fitted to the shape in question. for the big bits that works well, but sometimes those things aren't following the animation perfectly or it just takes too much effort for a tiny flub that most people just overlook anyhow."
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m4rjai | How do graphics cards actually work? | The title says it all. How do they work? I never fully understood how they did. I know that they help to render and display images, but how exactly? & #x200B; Edit: Thanks for all of the great replies! You guys really helped me to understand what exactly a GPU does, and why it's needed. | Technology | explainlikeimfive | {
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"Your CPU is good at doing general math calculations, and it's not really optimized for crunching anything specific at that hardware level. Your GPU is also really good at math, but it's specialized in doing math with matrixes. When you're rendering images onto the screen, they are able to calculate which pixels or which lines go where way faster than a CPU, and that's how they help.",
"I always thought there was little gremlins who drew pictures really fast so I’ll be thrilled to know if someone can write a smart answer",
"They are basically just little computers that specialise in rendering instructions into images that can be displayed on a screen.",
"CPUs are built for sequential calculations. What that means is basically that for your calculations, you have some steps you need to go through, and you cannot do one step before all the steps that came before have completed. That is why CPUs usually have a handful of cores (just one for the longest time, though currently they are usually in the 4-8 range for desktop computers, maybe 2 for the low end and 16 for the high end - though servers or workstations can go above a hundred nowadays). However, those cores are really fast at going through the steps of a calculation. However, when you look at an image, the calculations needed to create an image are not all like that. You have a large area where tons of similar calculations need to be made, for example things you need to calculate for every pixel of your monitor or every object that appears on screen. And the bottom-right corner depends no less on the top-left corner than the top-left corner depends on the bottom-right corner. So you are not limited to calculating everything in a fixed order, you can do calculations for multiple areas of the image at the same time. That is why GPUs are built to have thousands of processing cores (the fastest consumer GPU on the market, the GeForce RTX 3090, has about 10000 cores - the CPUs it would commonly be paired with, such as the Core i9 10900K or the Ryzen 9 5950X, have 10-16). Each individual core is quite a bit slower than a CPU core, but because of their sheer number, there are certain problems, especially those that can be divided up almost arbitrarily into mostly independent calculations, that it is faster at by just a ridiculous amount."
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m4wscx | How do electronics always finds themselves in situations where they need to be rebooted to work properly? | Technology | explainlikeimfive | {
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"Imagine you have directions on how to drive somewhere. You just have all the turns you're supposed to make. Then let's say you get to an intersection and there's an accident blocking the way. You end up missing a turn. Maybe the directions you have still work, but unlikely. It might be really hard to get back on track depending on exactly what turn you missed. If you could teleport back to the start and resume, you know that the instructions are supposed to work. Something similar happens with electronics. A bug can happen because of some random circumstances that creates an unexpected situation. The program then keeps carrying the error forward, so it causes bigger and bigger problems. If you restart, you get a clean state to work from. If you don't get that one little error, then it doesn't compound into a big one.",
"In addition to these other answers, sometimes software is written in a way that causes something called a memory leak. Sometimes a program is written in a way that an error tells the software to write to short term memory (RAM) without clearing old data out and eventually you're essentially putting 10 gallons of information in a 5 gallon hat and that causes issues too.",
"When a program runs, it tends to do all of the necessary setup at the beginning. If any of those things that were set up in the beginning develop an issue, restarting and repeating that setup is the fastest way to return to a good state. This is because while computers are good at detecting errors, they aren't perfect. If an error slips through, the computer, assuming it's caught all the errors, will treat this erroneous data as correct, which can have strange consequences. Errors like this are rare, however, so fixing them without restarting requires a lot more work than just restarting. Let's say you're adding 100 numbers by hand. You're 3/4 of the way through when your friend tells you you've made a mistake. You don't know where you made the mistake so you have two options. You can go back through your numbers and carefully check each addition or just start over and assume you won't make the same mistake twice. In computers there's a bit more to it but the idea is the same. Sometimes, your software uses other software you don't own. You don't know how it works or how to fix it, it's just a black box. In the analogy, this is like some of your 100 numbers being told to you by someone else based on their own math. It's hard to know if they gave you the wrong number, but you know it's unlikely, so restarting will normally fix the issue.",
"The best analogy I can think of is a whiteboard or a chalkboard. You can write on them all day, and usually you can clean them off with a dry eraser. Eventually, there's enough residue on the board that you have to use a wet spray for a true reset. Electronics can gather residue as well, whether it's static electricity or bits/bytes in the wrong positions. In the same way that you deep clean a board with a spray, you deep clean your electronics by turning them off and letting them rest for a bit."
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m50xe8 | How did vacuum tubes work? What were the differences between them and some of the earliest transistors from Bell Labs? | Technology | explainlikeimfive | {
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"In a nutshell the 'filament', sometimes known as the cathode, the part that heats up and glows, generates a potential stream of free electrons. The Anode, of the main output of the tube, collects these electrons. In between are typically one of more 'control grids'. Their purpose is to control the flow the passage of the electrons from the cathode to the anode. By varying the amount of voltage on these control grids you vary the amount of electron flow. In the simplest semiconductor there will be three layers of semiconductor material. Electrons will flow from one end to the other, with that flow regulated by the middle one. A voltage applied to that middle one will vary the output, just like in a tube. The basic function is the same, but tubes were invented in a time when semiconductors didn't exist. This is exceptionally simplified, but I hope it gives you the idea."
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m56jus | Why is usb a serial port and not a parallel port? | Technology | explainlikeimfive | {
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"It is serial because the transfer speed that was required could be managed with just two data lines with differential signaling. It also has two wires for power so a total of 4 wires. If you can have fewer wires you can make cheaper connectors and cables. USB is designed to be a way to connect stuff. This is the main reason that USB is series because it will be cheaper. Later USB standard add extra wires for dor signaling so USB 3.0 have2 additional differential pairs and a signal round for a total of 9 wires. The extra wires allowed higher transfer speed. USB-C has 23 pins connectors but only 16 wires and a shield in the cable. The difference is because some pins are duplicated do the connector can be flipped. It uses 6 wire pairs for singaling. & #x200B; Even if USB 3.0 and the USB C has multiple pairs of wire for signaling they still operate as serial connection side by side. A parallel connection would require the same timing on all wires and you would need an extra clock wire. It also requires tighter tolerances for the wire and connectors. Using them as a separate serial connection that is self-clocking is a simple way to obtain high speed. Parallel connection is simple to use if the speed you operate at is not limited by the performance of the wire but of the electronic, that drive it but it get harder and harder to do when you start to be harder and harder to do if you include signaling speed so you are closer to what is possible with the wire.",
"A single well-insulated wire is less thick than several poorly-insulated wires, so serial connections are inherently more space-economic than parallel connections. This allows USB to have thinner wires and smaller ports, which is desirable for a ubiquitous connector. This advantage magnifies with the length of the cable, which is why parallel connectors are usually only used internally or for short distances.",
"A parallel port use multiple signals and send one bit per signal in parallel to send the complete bit. A serial port use only one signal and send one bit after the other in serial. You would think that a parallel port would be faster and that is true in some cases. For example memory buses are still parallel. The problem is that in a parallel bus you need all the wires to be of the same length and quality in order for the signals to stay synchronized. This becomes a problem at higher speeds. Especially as you need so many wires it is hard to make them all the same. So a serial bus can be made much more robust, both because there are fewer wires but also because the wires does not need to be synchronized with each other. This means that even though you only have one signal you can easily increase the speed of that signal to regain any lost bandwidth. It is also much easier for the consumer as the cables and connectors are much smaller and easier to work with.",
"Because it’s way smaller than a parallel port, only having 4 wires instead of the 10 or more you would otherwise need, And it can be as fast or even sometimes faster because you can send information quicker over serial, as parallel at higher speeds can have issues with different bits arriving out of sync, even wire length can cause problems, and cross-talk between the wires",
"Serial communication sends one bit at a time over one wire. Parallel communication sends many bits over many wires at the same time. That makes parallel sound better and faster right? Well it used to be, however at high data frequency in a parallel connection it becomes difficult to keep your signals in sync. It's important for parallel communication that the signals on each wire are perfectly in sync or else you might start receiving mismatched bits from earlier/later transmissons. That little bit of extra solder on one wire, or the bit of dirt on one pin can really start to make a difference. This requires expensive electronics and high quality, bulky cables with bulky connectors. The original USB 1 & 2 only needed 4 wires, this meant it could be incorporated into low cost devices no problem. It also meant the cables themselves were cheap, it meant the connectors could be small so you could fit many of them onto a laptop, and not having to manage the parallel woes made the electronics cheap."
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m5aiwm | What is actually a "military grade cryptography" we often see in action movies? What makes it different from regular cryptography? | Technology | explainlikeimfive | {
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"It's Hollywood buzzword jargon, basically. \"Military-grade crypto\" means a cryptographic standard that the military has adopted to protect its information. In 2021, that standard is AES-256 (for top secret data). But...your wifi is protected by the same encryption standard (as long as you're using a recent standard, that is). Calling it \"military-grade\" doesn't mean anything super high-tech and fancy, in this case.",
"In the 90s, the United States actually did have export controls on encryption. If you wrote software that encrypted things, and you sent that software to another country, you could go to prison. (A well known cryptographer got around this restriction by printing a \"book\" of computer code to do strong encryption!) By around the year 2000, two things became clear and had been for a while: (1) the cat was out of the bag and the whole world had access to strong encryption, (2) online fraud was a big problem. Because of that, most export controls were eased. Before those export controls were eased, saying your encryption was \"military grade\" *did mean* something. It still does. The Advanced Encryption Standard *is developed by* the US government and presumably is used by at least some of the US military. But it's nothing special anymore, if it ever was.",
"They just want it to sound fancy on screen. The military isn't using anything better than the current consumer stuff.",
"The NSA defines 4 \"[types]( URL_0 )\" of crypto devices. \"Type 1\" is military grade crypto for classified applications. It's much more secure than the stuff used on the Internet."
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m5bkoy | How was early CGI transferred to film? | I fell down a rabbit hole of early examples of CGI from the late 50's through the 70's, and the vast majority of the videos I've found are film transfers, not video tape transfers (now that I think of it, would there be a difference in how it's transferred?). How on Earth did they transfer it from computer to film? My best guess is they would point a film camera at a CRT, or something along those lines, and I get that idea from seeing a video of one early CGI animation being transferred that way. But I can't find a lot of info on it aside from that, even after Googling, asking my dad who's an engineer, and even asking my friend who actually does CGI. I did see another thread on here explaining how digital video is transferred to film with laser scanning, so maybe even something like that? I really don't know a lot about this sort of thing, it's not a passion of mine, I'm just down a random ADHD rabbit hole and now I'm very curious. Thanks in advance for the help! EDIT: Thanks for all the answers! I've had a lot of trouble finding the right search terms, so this is great! < 3 EDIT 2: I should have specified one of the examples I was talking about. Here is a 1972 example showing the first polygonal 3D CGI URL_0 It was made by the guys who would later go on to form Pixar. Just thought I'd share this to show exactly which rabbit hole I'm down. Though special effects, both practical and CGI, fascinate me and am glad to have learned a new extra things! | Technology | explainlikeimfive | {
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"The earliest examples of CGI were indeed recorded by taking photographs of the CRT screen, one frame at a time, on 35mm film. Once you have the animation on film, it's relatively easy to composite into live-action footage. People had been combining live-action with hand-drawn animation by drawing onto individual frames of film for a long time now. Gertie the dinosaur was made in 1914 for instance. Disney, in particular, pioneered a multi-plane camera system that allowed animators to stack plates of animation frames on transparent backgrounds to create a final composition for photography to create a single frame of animation. A stack might contain for instance background, elemental animations like candle flames or water drops, plates for each of the characters and so on until a complete frame was created and photographed.",
"With something like a [Dicomed]( URL_0 ) camera designed to transfer pixels to film. I actually wrote a printer driver to send a series of TIFF files to “print” to film back in the early 90s. That was a lot of fun.",
"Artificial effects varied greatly in techniques through the early years. Once computer generated graphics were feasible, special optical printers were used to introduce them to film (Westworld, 1970), but these were pretty quickly replaced once digital compositing was achievable in the 80s - the film was digitally scanned and edited."
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m5cbpt | Sonar and Radar | Why are sonar and radar displayed as a line rotating around like a clock hand instead of a circle radiating out from the center? | Technology | explainlikeimfive | {
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"Because generally both devices work by having a directional antenna that sends out a pulse of radiation (or sound) and then detects the return pulses. In order to cover the entire airspace this antenna has to rotate, so you get the sweep effect on old radar screens. (Newer ones, although they work the same way, don't have the sweep visible because it just confuses the view)."
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m5cug4 | Really confuse about ddns | Technology | explainlikeimfive | {
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"Ok so the internet is all numbers that are addresses like for houses. But numbers are hard to remember so people made domain names to hide the numbers that's dns. So unless you buy a static address your address constantly changes making it hard to attach a dns to that address. You would have to keep updating your dns with the new address each time it changed. This is where dynamic dns or ddns comes into play. Instead of you updating the address each time a service updates the address each time it changes keeping your dns pointed to the correct address."
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m5d75j | What were those bank tubes in the 80s, and how did they work? | You would drive through and deposit your money into the tube. Then it would get sucked up and go in to the bank itself. Why did they use them and when did they stop? | Technology | explainlikeimfive | {
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"They are pneumatic tubes and are still in use at many banks. They use air to move the tube from the car to the window. It’s an easy way to have multiple lanes when there is only one drive up window",
"Where are you from? Those are still very much in use in America"
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m5eg59 | how does the whole anti noise thing work in headphones to create noise cancellation? | Technology | explainlikeimfive | {
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"A sound wave is a pressure wave. When we hear a sound, what our hearing system detects are rapid changes in how compressed or spread-out the air is (i.e. how closely the air molecules are packed together). What we perceive as a particular sound is determined by the specific patterns in these rapid changes in air pressure. Active noise-cancelling headphones include microphones to detect the \"ambient\" sound i.e. the sound that's there in the space around you (in the room, car etc.). When, in a particular moment, the ambient sound has a region of compressed air, the headphones generates a compensating region of spread-out (“rarefied”) air, and where the ambient sound has a region of spread-out air, the headphones generate a compensating region of compressed air. All this is happening incredibly fast, with potentially thousands of such changes every second. In this way, the headphones generate a sound that's in a certain sense the \"opposite\" of the ambient sound. When this generated \"opposite\" sound is added to the ambient sound, the compressions match up with the rarefactions and vice versa; the result is that the pressure changes that make up the ambient sound disappear, leaving only the sound of the music/whatever from the device the headphones are plugged into. Edited for clarity, and to add... A sound wave is a different kind of wave to a water wave, but they can both be described in the common terminology of waves (e.g. frequency, wavelength, amplitude and interference). What noise-cancelling headphones do is an example of “destructive interference”."
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m5fuiw | How do devs change the version number thing? (version 0.2.3, version 1.9.0) | Technology | explainlikeimfive | {
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"General rules of thumb: * 0.0.x - Prototype builds * 0.y.x - Something resembling the intended product, getting better as y and x increase * 1.0.0 - First release, product as intended function wise * 1.0.1 - Bug fix/very small change over 1.0.0 * 1.1.0 - Minor change like a new feature. Doesn't fundamentally change the existing software. * 2.0.0 - Major change, significant fundamental changes to form and function. Generally not back-compatible especially with save files. API changes breaking other people's software that interacts with this one (API - application programming interface, is how you can use & interact with other people's code from your code).",
"They're made up. There are various standards, which other commenters have mentioned. But at the end of they day, each company does slightly different versions of a \"standard\", or just wing it. Personally, for a library that is consumed by other developers, I would use semantic versioning. However for work we just use an incremental version for releases, since no client cares about the version they're running, only we do.",
"Each number in the version number means something. At one of my previous jobs it went: ReleaseVersion.ClientReviewVersion.InternalQAVersion.DailyBuild We generally didn't inform the client about the Daily Build version because they tended to panic (why are there so many Daily Builds? [Which weren't literally \"daily\"]). I'm sure there are many different ways to number versions, and I'm sure that are some accepted Best Practices, but we went our own way"
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m5tlp8 | how does the eco setting on a washing machine save energy and water by washing the laundry for *longer*? | Edit: Thank you to everyone that replied! | Technology | explainlikeimfive | {
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"The motor of the washing machine uses very little power when it's just moving the clothes around. It's a bit more during the spin cycle, but that doesn't last very long. The vast majority of the power is used to heat the water, so if you can use a lower temperature and/or less water and instead just have the motor do its thing for a longer time, you use less energy (and water) overall.",
"Whenever you clean something, there are 5 basic elements involved: Water, Agitation, Time, Chemical, Heat (WATCH for short!). Think of them arranged as the wedges of a pie chart. For something to get properly clean, there is a balance of these 5 things. You can reduce one or more of these elements, but in compensation, one or more have to be increased. In modern washers, the amount of water, chemical, and heat is reduced, at the expense of time and agitation. The washer is relying more on the mechanical action of agitation to shoulder the load of soil removal, but obviously, this takes longer. In terms of our pie chart, W, C, and H wedges are smaller, and the A and T wedges are made larger to compensate. As someone mentioned, it takes less energy to agitate the clothes in the wash wheel than it does to heat the water to higher temps, hence the energy savings.",
"The energy required to heat the water is significantly greater than the energy to pump the water or spin the tub. A typical electric water tank is 4500 W. A washing machine's boost heater (for better machines, if incoming water is too cold) would be 1500 W. A pump might be 100 W. The main drum motor might be 300-500 W. Kinetic energy to heat 20 L of water from 20 to 40 C: 1,600,000 J Kinetic energy to spin a stopped drum full of 40 kg clothes+water up to 300 rpm: .5 × (.5 × mass × radius^2) × (angular velocity)^2 = 1.2 × (37 rad/s)^2 = 1600 J (assuming solid cylinder for moment of inertia)",
"It uses the water, longer. therefore it can get away with using less water, since it uses that same water more efficiently. think of how long it takes for water to seep into a thick cloth",
"The eco setting on my washer uses colder water than the warm setting. Heating water takes a lot of energy. A big chunk of household energy use is just heating water and heating|cooling air."
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m613i9 | Why are graphics cards in such low supply? | Title mostly says it all. I know about crypto mining and such, but why is demand suddenly so high and supply suddenly so low? Also, why are they trying to stop people from crypto mining if they get to sell the cards anyway? | Technology | explainlikeimfive | {
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"The pandemic has affected supply of a lot of electronic items, graphics cards included. As for why graphics cards manufacturers wouldn't want miners to scoop up their entire stock, well, it looks bad for them if no \"normal\" user can get one of their cards--not to mention, users looking to upgrade might go for a lower end device that the manufacturer doesn't make as much money on.",
"So, the main chips are made from these wafers (big flat circles) of silicon. Those wafers are fed into machines that know how to write on them to print circuits (not exactly, but it's an analogy) and the size of the writing is predetermined, like the thickness of the lead on a pencil. The thinner the writing, the closer things can be together, making more chips from a wafer, because if you change that thickness (node size / process) you have to take many other things into account. The main thicknesses being used are 7nm from a company called TSMC and 8nm from Samsung. You can't just spin up more capacity, because it's super expensive, like billions of dollars in investment, and years to produce, but if you are in the fab business (making chips for customers) you want to sell all your capacity, and have as little waste as possible. But... demand is through the roof. The pandemic has made people reverse a trend where they didn't need a computer at home, or maybe only one. What happens when you suddenly have a couple of kids doing homework, and one or more parents work from home now? You need more computers, right? Well, remember when I said you can't just spin up more capacity? All that time, those wafers, they were sold. They get used to make memory chips, graphics chips, chips for motherboards, CPUs, etc. There's no more to go around, but people still need computers. With the pandemic, factories slowed down, shipping companies were seeing a surge, and raised prices, Taiwan, a major location for manufacturing computer and electronic parts is in a drought, which means they are shipping in water for their factories, and that slows them down, too. Texas had a major snow, plus blackout, and they do a lot of fabrication, too. Shutting down a factory like that makes starting it up a lot harder, and it kills supply. So you have weather, illness, demand, supply, and competition for resources all coming together to create a very big problem. Now, the crypto miners are adding to the frenzy. See, when those factories took their orders for capacity... the manufacturers of those parts had to take a guess. Guess too high and you wind up with too much stock, and you have to sell for less. Nobody wants to do that. It can erase all your profits and put you out of business. Guess too low, and your virtual shelves are empty. They needed to guess over 18 months ago, and they guessed wrong. You can correct that, to a degree, but nobody could have foreseen all these things coming together. If they guessed they would need 15% more than last generation of products, that would have been fine in most normal years, but we are looking at probably 400% higher demand, here. Others have answered why these manufacturers tend to avoid looking too cozy with miners. It makes gamers resentful, and they don't like that people with deep pockets who don't care if a card is $700 or $1300 if it's profitable, while they may have saved up for a year, waited, and can't find any cards."
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m654jo | How do computers remember to turn back on during the restart option? Isn’t it temporarily shutting the computer down? | Technology | explainlikeimfive | {
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"Inside of your computer is a \"smaller computer\" (usually called an \"embedded controller\") that is always on, even when the rest of the computer is completely off. It does things like keeping track of time (note that the clock on your computer doesn't reset even when you unplug it), handles the power button, often also power/hard drive/battery LEDs, fans, etc. It also manages power delivery to various components and can talk to the rest of your computer. When you tell the computer to reboot, the EC switches everything off, but knows to switch everything on again later.",
"EDIT: when I posted this there were only a few not so accurate comments in the thread, lots of good info here now :D ~~So much bad information in this thread... It does restart all the way (not halfway like some people seem to suggest).~~ This is why you see the bios etc on reboot. Anyways a TLDR copied from [here:]( URL_0 ) `power states in your computer are controlled by an implementation of ACPI (advanced configuration and power interface). At the end of a shutdown process, your operating system sets an ACPI command indicating that the computer should reboot. In response, the motherboard resets all components using their respective reset commands or lines, and then follows the bootstrap process. The motherboard never actually turns off, it only resets various components and then behaves as if the power button has just been pressed.` The only difference between shutdown and reboot is at the end of the OS's shutdown process, which ACPI command is called. (turn off power vs reset) Note sleep/hibernating are a different beast altogether. If you're interested in further reading, \"ACPI\" is what to google.",
"The top answer right now seems a bit over technical and not ELI5 to me. Essentially your computer never turns 100% off. There is a constant flow of a tiny amount of power from your bios battery. When your motherboard gets the command to shut off it shuts down all the main components but still keeps the tiny bit of power needed to start the bios. Restart just does that but then immediately turns all the main components back on.",
"A good analogy of how the restart button works goes like this: When you shut down your computer it is like a chef cleaning up and going home for the night. When you abruptly shut down your computer it’s like the chef going home without doing any cleanup and when they arrive back in the kitchen they have a lot of cleaning up to do before they can begin their work. This is why when you abruptly shut down your computer it takes longer to start up again than usual. When you restart your computer, it is as if there is a break in the dinner rush which gives the chef an opportunity to clean up their workspace and get ready on a fresh slate again without going home. So essentially your computer will continue running its bare minimum to clean up and restart again as if it has been shut down and started up again",
"Your computer has more processors than just your CPU. The motherboard is covered in little processors that each do different jobs. The motherboard also draws power from the Power Supply Unit even when the main CPU is powered down. When you press your 'ON' button, an electric shock hits an ACPI module on your motherboard that initiates the bootup process. ACPI is a sort of design agreement for how to manipulate the power in the motherboard. When you tell your computer to reboot, your Operating System shuts down as usual, and then instead of sending a 'turn me off' signal to the ACPI module, it sends a 'reboot' signal. ACPI cuts power to the CPU, RAM, and rest of the computer as usual, and then it begins a new bootup process. You can also set up most computer to Wake-On-LAN, which is when a computer is connected by an Ethernet cable to a network, and a specific set of signals sent across that wire will be relayed from the Ethernet port to the ACPI module, which then starts booting up the PC. There are also settings for ACPI on how to handle power failures. Let's say there is a power outage and you've got a battery backup that is connected to your computer, so when the battery gets low it sends a shutdown signal to the OS. The OS closes all of the processes, and then asks the ACPI module on the motherboard to shut down power. When power is restored, the UPS doesn't send any information to the computer, because the computer has been shut down. But the motherboard is receiving power again. If the ACPI module has the setting toggled, it can send an 'ON' signal to the rest of the computer just as if the 'ON' button had been pushed.",
"I've answered this in another thread. The OS uses a generic command and ACPI BIOS to send power commands through the system bus to the Power Supply and Peripherals. Each peripheral will enter a power mode and shutdown or move to an idle state in a safe manner. The onboard logic of each peripheral knows how to do this. So the hard drive will park safely and flush caches as needed. The CPU will enter a different CPU power state. The Power Supply will then enter an idle power state and will switch state to full power after x amount of time. As long as the power supply is plugged in and the ATX switch is on the power supply will be receiving power and will be active or idle. The computer may seem off but it is not. A full shutdown wil place the power supply into idle and will not power certain devices of a certain power range so your hard drive and fans will be powered off. Your CPU, Motherboard and some peripherals such as your network card will receive a small amount of power in this state. A restart will bring all power lines back up to full power causing your hard drive to activate which will start the boot process.",
"You know how when you go to sleep, you can’t move or see or smell things? But then you wake up and can do all those things again. Your brain turns off all the things you do when you’re awake, but your brain also remembers to wake you up. When you press the restart button on a computer, everything turns off, but there’s a small piece of the computer always powered by a little battery that remembers to turn everything back on again.",
"I think this post breaks Rule 7 [ELI5: How do computers know to power back on when you restart them?]( URL_1 ) [ELI5 how can a computer turn itself on]( URL_8 ) [[ELI5] How does a computer know to boot up again when you select to \"restart\" it?]( URL_9 ) [[ELI5] How does a computer restart if it turns everything off?]( URL_0 ) [ELI5: How does a computer restart automatically, just because I clicked \"restart\" versus \"shutdown\"?]( URL_2 ) [ELI5: How does computers know that they have to restart after shutting down?]( URL_11 ) [ELI5: How can a computer, durning restart, shut it self down and turn on again]( URL_14 ) [ELI5: How do computers restart?]( URL_6 ) [ELI5: How does a computer know to turn back on after you tell it to restart?]( URL_3 ) [ELI5: How does a computer know to turn itself back on again during a restart?]( URL_15 ) [ELI5:How does a restart button work?]( URL_17 ) [ELI5: How do computers remember to turn back on when you click the restart button in your OS and it shuts off?]( URL_16 ) [ELI5: How does a computer turn itself on when it's off during a restart cycle?]( URL_4 ) [ELI5: How exactly does a computer restart?]( URL_10 ) [ELI5: How when a computer is ordered to restart, it doesn't 'forget' to turn back on when it shuts off.]( URL_5 ) [ELI5: When restarting a computer, how does the computer know to turn back on after shutting itself down?]( URL_12 ) [ELI5: How does a computer restart itself?]( URL_7 ) [When you restart a computer, after it shuts down, how does it know to start up again?]( URL_13 )",
"The very last command the computer gives during the shutdown is a special command named \"reset\". In some machine languages just called RST. It's a direct command to the processor to give an electric signal on a wire that is normally unused, but leads to every device into your computer. This is the reset line. For the processor itself the reset command means to put the adress counter to zero and just continue working. So the processor reads and processes the adresses 0 and 1 and so on. At this adresses is the ROM (a hard coded memory) with commands to jump to the boot routine and so the computer didn't stop at all, but just jumped back to zero. And all the other devices does the same or similar things. This is not the whole story. But for an old ZX81 it works this way. In former times the reset line was often cut within an ethernet card with wake on lan. So the card could wake the computer up after a shutdown without loosing its own preferences. That made a lot of trouble. With any change on those cards you had to switch the computer completely off, so they can't override your adjustments.",
"Computers, when they first boot, generally start by executing instructions from memory address 00000000. When a computer is first turned on, it gets that address naturally anyway (because there's no voltages on the pins at first, which corresponds to 00000000), and it requests whatever is at that memory location and starts executing whatever is there. On old PCs this would have been the BIOS, nowadays it's UEFI, on other machines (e.g. Raspberry Pi) whatever you want to boot (the bootloader) is set up at that location by the firmware or other hardware. In the old DOS days, a \"warm boot\" (what we'd call a reboot) was literally just an instruction to start executing code from memory location 00000000 again (literally the instruction JMP 0000 in some cases). That code then clears memory, initialises hardware, finds the storage and OS, etc. as if it had just turned on. That hasn't much changed, except just jumping to that location is probably impossible nowadays - it would likely damage the computer filesystems, allow people to interfere with programs, etc. But a restart nowadays is basically saying to the OS \"clean up after yourself, Windows/Linux/MacOS, and then when you're done jump to address 0 and start executing that code again\". Hence a \"restart\" is really just a shutdown procedure (without the actual hardware shutdown) followed by a re-initialisation as if you've just turned the computer on. An actual hardware shutdown is the exact same kind of \"clean up\" process, followed by an instruction to the motherboard to cut the power supply (but even then, modern computers rarely go entirely off, there's always something listening to see if they should turn back on, whether it's a software-controlled button, a network interface or a timer-chip). They don't \"remember\" to turn back on, because in this case they never really get turned off. The CPU just turned to the front of the instruction manual and starts doing all those \"if this is the first time you've turned on, then you need to clear memory, initialise hardware, etc. etc.\" instructions that it would normally only do when it's just been turned on. Back in the day, \"cold-boot\" meant actual power-off and was a physical action to turn it back on. \"Warm-boot\" meant this kind of restart/reboot/re-initialisation process (often initiated by pressing Ctrl-Alt-Delete but that key combination does something very different nowadays). We don't really use those terms any more.",
"I think the booting process is handled by the motherboard not the system, it's clearly visible while fans don't turn off (also managed by the mobo)",
"The Operating System is actually separate from the computer itself, the part that translates between the software and hardware (the BiOS) doesn't turn off when you do a restart, because it just unloads and reloads the operating system rather than unpowering the entire computer.",
"Inside the computer motherboard is a component that contains Non-Volatile Memory. The data written to that controller is kept alive by CMOS, which is a [button battery]( URL_0 ). However, even if that lithium battery died, the BIOS would revert to a default state (Factory Default Settings), which tell your computer how to boot, reboot, and everything else."
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"https://www.reddit.com/r/explainlikeimfive/comments/iueo4m/eli5_how_do_computers_know_to_power_back_on_when/",
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"https://www.reddit.com/r/explainlikeimfive/comments/5eqssj/eli5_how_does_a_computer_know_to_turn_back_on/",
"https://www.reddit.com/r/explainlikeimfive/comments/3hoqua/eli5_how_does_a_computer_turn_itself_on_when_its/",
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"https://www.reddit.com/r/explainlikeimfive/comments/5mgr6y/eli5_how_do_computers_restart/",
"https://www.reddit.com/r/explainlikeimfive/comments/1uumo1/eli5_how_does_a_computer_restart_itself/",
"https://www.reddit.com/r/explainlikeimfive/comments/gctkje/eli5_how_can_a_computer_turn_itself_on/",
"https://www.reddit.com/r/explainlikeimfive/comments/d6cvq7/eli5_how_does_a_computer_know_to_boot_up_again/",
"https://www.reddit.com/r/explainlikeimfive/comments/3bb8t2/eli5_how_exactly_does_a_computer_restart/",
"https://www.reddit.com/r/explainlikeimfive/comments/6ged6x/eli5_how_does_computers_know_that_they_have_to/",
"https://www.reddit.com/r/explainlikeimfive/comments/288ebp/eli5_when_restarting_a_computer_how_does_the/",
"https://www.reddit.com/r/explainlikeimfive/comments/m12rt/when_you_restart_a_computer_after_it_shuts_down/",
"https://www.reddit.com/r/explainlikeimfive/comments/5zwo6z/eli5_how_can_a_computer_durning_restart_shut_it/",
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m65rba | How do "smart" dishwashers know that the dishes are clean? | Technology | explainlikeimfive | {
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"They do a pre-wash cycle that rinses the dishes with plain water to see how dirty the water gets (basically shine a light through it) during this cycle. It then works out how dirty they are likely to be. That is also why you put the detergent in a closed receptacle in the door - it doesn't drop into the water until after the pre-wash.",
"They have a sensor that measures the opacity of the water. As more food gets washed off the dishes into the water, it becomes darker and lets less light through which is what the sensor measures. Its a pretty crude method that allows the machine to roughly estimate how heavy the load is and therefore how long the washer needs to give for the enzymes/chemicals in the tablet to break everything down. Pre-rinsing is generally a waste of time. This removes the food particles from the water which are actually part of the scrubbing action - so no food particles = worse cleaning. Certain things like oatmeal/porridge might benefit from a quick blast under the tap to loosen any stuck on thick bits."
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m684g2 | How did people get by before dentistry was a thing - did we simply lose all our teeth or suffer from the pain constantly? | Technology | explainlikeimfive | {
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"We mostly had far fewer dental problems because our diets weren't loaded with sugar. And we ate a lot more fiber which kind of help with 'brushing' your teeth as you eat. The majority of our health issues are caused by modern diets and lifestyles. People didn't have those luxuries in the past and didn't suffer the associated ailments as a result.",
"People in Pompeii had really nice teeth do to a low sugar diet and naturally occurring fluoride in their water.",
"[Tooth abscess was a leading cause of death up until quite recently]( URL_0 )",
"Barbers were dentists and minor surgeons - that's the origin of the barber's pole, a bloodstriped bandage.",
"It was not uncommon to pull out all your teeth and replace them with dentures. Even before you had any issues with the teeth you already got. This is a practice so old we do not know when it started and it just recently stopped. People would do this until the 60s when dentistry had become common enough that people prefered keeping their teeth. So a lot of the old people walking around with dentures today got them in their 20s even before they had issues with tooth ache.",
"Shorter lifespan and different diet meant it wasn't a major issue, but if it did occur you just lived with it or died from it.",
"Point of reference: I'm 38 years old, and I haven't been to a dentist since somewhere in my early twenties. I eat a low-sugar diet, I drink lots of water (washing down whatever acid does build up in my mouth) and I don't smoke/drink/etc. But, yes, if you had trouble with your teeth before dentistry it was going to suck big-time for you. As in you might just be eating soft foods for the rest of your life. But that was the same for most medical problems, which is why the average lifespan was a lot less (fun note: The majority in the gain in average lifespan didn't come from people who used to live to 60 now living to 70, it came from far fewer people dying at young ages and living to 60 instead).",
"We died young. A lot of times from abcessed teeth, or a random sickness. We generally didn't live very long pre modern medicine.",
"Yes. But there's evidence that we didn't have as many problems with teeth as you might think. Though modern hygiene does indeed help you live longer and maintain your health longer, modern life is also harsher on our bodies (sugar and acids on your teeth, etc.). Think of the skeletons that you see on archaeological digs. How many have no teeth, or crooked teeth or sometimes have no missing teeth at all? This is why Bear Grylls can spend months in the wilderness with only basic facilities, etc. If you're using your teeth to do what evolution has designed them to do, they last far longer, and if your lifespan is already less than ours, they'll survive your whole lifetime without much of an issue for the majority of people. Living longer, and having luxuries have actually made things worse - you're less likely to die outright, but far more likely to outlive your natural immunity, the lifetime wear-resistance of your tooth, etc."
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m6f2ru | What does a PC monitor do that a television does not? | It seems to me that over the last decade or so computer monitors and television technology has converged and, on the surface offer the same thing. But people are willing to pay a premium for a PC monitor. For example, I’m looking at this 32 inch monitor \[4k, 60h\] and they want $6k?! Meanwhile even if I wanted to spend more, the absolute most expensive 32inch tv I can find is less than $700. | Technology | explainlikeimfive | {
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"At its core, nothing. But the specs tend to be different, as different things are more useful for TVs versus PCs. Apples to apples between resolution, size, refresh rate, response time, color space, brightness, and pixel density - they should be about the same price. PC monitors often have higher refresh rates (not in your case), and much lower response times. A TV might have a response time (the time to shift a pixel from one color to another) around 50-60ms, whereas a monitor above 5ms generally isn't particularly good. Pixel densities may be larger as people are generally sitting closer to monitors vs TVs, they're not making money off of selling your TV app usage and personal data, which also contribute to prices."
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m6q7rw | Why do videos from 10+ years ago have such potato quality these days when they looked fine back then? | Unless I'm misremembering, but I feel like I didn't struggle to make out details in some videos back then the way I do these days, because the quality seems so degraded. | Technology | explainlikeimfive | {
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"the best reason i can think of is that video looks best when it is the same or higher resolution than the screen you are watching it on. Lower res video looks better on a low res screen than it does on a higher resolution screen most of the time. (this depends on how the video is up-scaled) Also you were used to that video quality at that time, and now you are used to something higher resolution and the transition has been slow. As the years pass nothing changes much, and then you look back and see how far tech has come.",
"It’s a combination of having your expectations elevated by modern resolutions and the fact that screen sizes are generally just much bigger now. You used to watch low resolution content on tiny screens and that was all you knew. Now you watch super high resolution content on very large, high resolution screens. The older content is no longer standing on its own, but being contrasted with these better images, especially when displayed on screens that play to the better quality content’s strength while highlighting the poor quality of the older content.",
"In addition to other comments, I think another reason could be re-uploads of poor quality. I know when I try to find a video that's 10+ years old, I usually find some crappy upload that was a screen-capture of a copy of the original."
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m6v1w0 | Why are old movies and videos are in a square frame and nowadays they are in a rectangle frame? | Technology | explainlikeimfive | {
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"It's all relatively arbitrary. The old 4:3 square-ish look was chosen because 4:3 was the most common type of film on the market when movies started being a thing. TV came along later and the key players in early TV had the chance to choose a different format since they weren't reliant on film. They settled on a wider aspect ratio because they thought having more horizontal space would be useful for capturing a bunch of people on screen at once. That change was later emulated by movies and frames have generally continued to trend wider over time, but it has always been in the interest of aesthetics more than anything else.",
"The oldest and earliest movies were done with at the time new equipment and often shot square or 4:3 (thats 4 wide by 3 high). This was due to the film they used and the screens they were shown on. Those classic silent films were generally 4:3, like almost all of them are 4:3. It was the nature of the equipment they used primarily. Gradually more aspect ratios were introduced, and movies, for both practical (the film and screen they used) and artistic reason, started to move to much more wide than tall. Some common aspect ratios in movies became 2.39:1 and 2.35:1, 2:1, 1.85:1 (1.85:1 and 2.39:1 are most common) and others as techniques and film and screens evolved to be able to support more diverse ways to make and show a movie. Artistically, a wider screen is viewed as being more \"cinematic\" while a less wide screen is more \"trapped\". Depending on the movie, you may want one or the other feeling. Many \"epics\" movies are shot very wide screen to feel more cinematic! Some crazy ones ae even stuff like 4:1 TV has a similar story, but the TV standard went from 4:3 to 16:9, which is significantly less than the movie ratios used which are now usually 2:39:1 or 1.85:1"
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m6w342 | How are security cameras around the world so easily accessible? | So today I saw the link of a website which apparently connects you to security cameras around the world. I want to know how is it possible? And since I did go to the website and did a few clicks (it was http), should I be concerned? | Technology | explainlikeimfive | {
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"It only links up to cameras that people put on the web, the vast majority of cameras store their information locally and not on the web.",
"Most security cameras come default with the username as admin and the password as password. Many people don't change these passwords. They broadcast to the web over http. Google and other web crawlers find these cameras. That website databases those cameras."
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m72eqc | What's the difference in sound quality or comprehension between an MP3 at 320kbps and a 24 bit audio wav file. - Also, what effect will playing these over bluetooth have on the sound and sound quality. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"ok, there are 2 concepts you have to understand, Bitrate and sampling frequency a digital audio recording makes images/samples of a audio recording at a specific interval being the sampling frequency, and with a specific size which is the bit rate. a CD does 44.1Khz at 16bit, which means it takes 16bit samples at 44.1Khz, and uses a codec called PCM, which uses around 10-12mb per minute and is considered lossless since all the information is stored but that's debatable. Now the issue is lossless vs non lossless. Mp3 is a compression format, its actually Mpeg 1 Layer 3, it first filters the audio for frequencies most people don't hear, and then uses mathematical algorithms to reduce the size of the samples, this can result in audio sounding more metallic, bass and treble sounding weaker, clipping... so a lot of people prefer using 192Kbps or even 320kbps, some people prefer 256VBR (variable bit rate) but others claim that variable bit rate causes distortions in the sound. but we have to differentiate between a digital recording and a compression format, PCM, DSD and such are more storage oriented and use as much space as they can to store the music while you have Flac, ALAC, Mp3, AAC, MQA and such which are compression formats. Now you have 2 categories in which they separate to, you have formats like Flac, Alac, Ape which are lossless, meaning that they do not discard any information and just compress the information to keep the sound identical. Others like MP3, AAC, MQA \"shave off\" information they considered not necessary for the listener, and then compensate during the decoding, so the audio is incomplete but the part which was removed is indistinguishable for 99% of the population, and considering 80% of the population listen to music from their iphone by airpods which are at best mediocre quality... now the bluetooth thing is something different. The idea is that between your phone and your bluetooth audio device there's a data link. that data link has 2 important factors, available bandwidth and latency. Now depending on the protocol you use, the bandwidth and the latency will improve. So you have basic SBC which allows \"acceptable\" audio quality, AAC which improves sound quality and then you have 3 Major proprietary protocols which come from 3 different companies - APTX from Qualcomm. which includes a HQ mode, Low latency mode and Adaptive mode, - LDAC from sony which has normal LDAC which is pretty good and LDHC which is a higher bandwidth version for higher quality. - the H1 and W2 which are proprietary for apple devices only. The problem with these is that for APTX and LDAC you have to pay for a license from the manufacturer, Sony for LDAC and Qualcomm for APTX, Also Qualcomm has its own Bluetooth chips in the QC series, but if you build a cheap speaker or headphone and use a mediatek or realtek chipset, you get the basic open codecs which are AAC and SBC. You can Expect LDAC or APTX from a set in the 100-200 dollars from Bose, Sony, AKG... but a pair of Soundpeats that cost 35 bucks on amazon, i don't think they splurged for the APTX license."
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m73ze1 | How do rewritable CDs and DVDs work? | To my understanding, hard drives are magnetic, and an electromagnet can be used to alter data. A CD or DVD is more visual; it uses a laser to read and write physical pits/troughs in the disc. If the disc uses physical pits, how does the laser carve them out in the case of a domestic rewritable disc? And how does it fill them in when it rewrites over them? | Technology | explainlikeimfive | {
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"text": [
"To make a recordable disc, you start with a plastic substrate that has blank grooves rather than a predefined pattern of pits. The blank grooves can keep the drive on track before the data is written. In addition to a layer of metal, the media includes a thin layer of dye. Pulsing at high power, the laser in the drive can ablate or \"burn\" marks in the dye. Read back with the laser at the normal, lower read power, those marks look like pits to the detectors in the drive. Because the high laser power permanently changes the dye, this format can be written only once. For additional rewriteable capability (CD-RW), a thin layer of so-called phase-change metal replaces the dye layer. That material requires two extra \"dielectric,\" or glassy, layers for protection. The drive employs a high-power laser to write amorphous marks in the metal layer, an intermediate-power level to write crystalline marks and a low-power level to read the recorded data. To the drive, the crystalline areas appear bright and the amorphous areas appear dark. As a result, the disc can be read in the same manner as a CD-ROM. The crystalline-to-amorphous transition is reversible. URL_0"
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m756pe | What does it mean when my phone says that my WiFi is not secure? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"It means that the wifi doesn't have protections in place that prevent mean people doing bad things to you by watching what you send to the internet through your wifi. It's kind of like if the postal service had an open door policy where anyone could open any letter they wanted, so it's best not to send things you don't want other people knowing through that postal service (like bank login details). Wifi that anyone can connect to, like the free wifi in hotels or cafes, are open to this. Ideally what you want to be doing is using a postal service where only you have the key, so no one can open your letters - only do important things on the internet when you're connected to your home, password-protected wifi.",
"Most WiFi networks are encrypted: the information between you and the WiFi router is encrypted by the radios at each end so that someone else on the network can't read any of the data you send or receive. However, public access WiFi networks (coffee shops, airports, libraries, etc.) often aren't encrypted. Whatever you send or receive over the WiFi network is readable by anyone else on that network. You need a separate layer of encryption, like a VPN or https:, to render that data secure. Your phone is warning you that you're on an unencrypted WiFi network, so unless you've got another layer of security, anything you send/receive might be visible."
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m7c4sm | How an oversupply of solar energy could lead to a blackout | I live in South Australia where 35% of households have solar panels. Some of these panels were temporarily switched off recently in order to avoid a "state wide blackout". How does an excess in energy to the grid cause a blackout? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Traditional power plants (except hydro) can't switch on/off instantly, it can take hours or days and costs $$. And obviously solar can't generate during the night, so those power plants have to be on and generating at night. But they can't stay on and generating _as well as_ all these solar panels unless there is demand to match the generating capacity (too much energy - > things start tripping to prevent overloads etc., harder to balance) so since the solar panels can be turned off pretty easily, they get shut off first. This is why Tesla and their giant batteries is such a big deal: if you can take the excess capacity from wind and solar and store it for use overnight or when its cloudy you _can_ turn off the generating plants and save a whole buncha money.",
"In electrical grids, the grid operators have to very closely match supply and demand. Because grids operate on AC (or alternating) power, which means the electricity in your grid \"flows\" by alternating directions at 50 hz, or 50 times a second. So, all the equipment in the grid is very finely tuned to work super well and efficiently at 50hz. The problem is, when there is a mismatch between supply and demand, it alters how the current alternates. Too much demand and not enough supply, and the alternating starts to slow down below 50hz, too much supply and not enough demand, and the opposite starts happening. So, you have all this very finely tuned electrical equipment that is meant operate at 50hz, with two much supply and not enough demand, that rate starts to increase to 50.5,51,52 etc. And the further it gets away from what the grid is designed for, the greater the chance that some equipment in the grid is going to fail increases. So, to prevent the chance of equipment failure, grid operators do their best to perfectly match supply and demand (to the point that in the UK grid operators take into account the half time of major football games like the world cup to account for millions of people getting up and turning on their microwave/kettle). And in this case they can to cut down on supply, so they disconnect some of the solar power.",
"Think about electricity as though it was water - it might sound weird but electricity and water behave the exact same way. So imagine that people start hooking up pumps to their faucets so that instead of water coming out of the faucet, they're pumping water back in. If water consumption otherwise stays the same what ends up happening is that the water pressure in the system goes up, so when you open a faucet somewhere water will come out much quicker than it would previously. The problem with this is that you can't just increase the amount of water getting pumped into the system to infinity. The pressure in the system keeps going up and it will eventually get to the point where there is so much pressure that the system's pipes will burst, at which point no one has water anymore. Electricity works the same way. The only difference is in how pressure works. Instead of the electrical \"pressure\" going up, adding more electricity to the system causes heat in the wires carrying the electricity. And the amount of heat being generated goes up really quickly - even slight imbalances in the amount of electricity can cause the more sensitive parts of the system, such as electrical transformers, to heat up so much that they catch on fire. To add onto this, its typically difficult for power plants to change their output. So if the people managing the electrical grid misjudge how much demand is going to exist a few hours in the future you can pretty easily end up with a situation where there is so much more electricity being generated than being used that the entire grid might burn itself out. If the grid operators have the ability to turn off home solar panels with a few minutes of notice, then that's going to be the easiest way to prevent the grid from overloading."
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m7g6ey | what actions fulfill the statement "by continuing to use our site, you accept our use of cookies"? | Technology | explainlikeimfive | {
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"Cookies are small bits of text sent in the HTTP headers with the response. When you received that page, there are probably cookies. Those cookies may not be permitted to be stored on your system, which is to say that your browser shouldn’t remember them. This is done by not sending expiration values with the cookie, to tell the browser it should forget after it closes. If you continue to other pages, they may take that as implied permission and send cookie headers with expiration values that allow your browser to store the cookies. They aren’t really installed, and they don’t do things by themselves, they’re just blobs of text, some of which can be used to identify you on return requests. Curiously, the only way to remember whether you accept cookies is to store a cookie. So if you decline, or ignore the acceptance, it may prompt you every time you visit. If you do accept, at least the cookie that notes that will be stored, and likely other cookies to remember you later."
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m7gnwm | the difference between a chromebook and a normal laptop | Technology | explainlikeimfive | {
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"Basically, a Chromebook's main function is to run the internet and cloud-based programs. As the name suggests, a Chromebook is integrated with Google's browser and apps. Since it's meant to be an internet machine, it has low-grade specs. It doesn't need a heavy graphics card since you're not installing games, it doesn't need much RAM since you're not running intensive programs, and--most importantly--it doesn't need much of a hard drive because you're not going to be installing and saving much to it. Again, since it's browser-based, it saves stuff to your Google drive. So there's actually very little disk space. A normal laptop is essentially supposed to be a portable computer. A Chromebook (or, more generically, a netbook) is supposed to be for internet and internet apps. Actually, you can think of your Chromebook as a smart phone with a keyboard, except it doesn't call or text.",
"A chromebook has more in common with a Smartphone or an iPad that fully fledged PC. It uses a simplified operating system that can only run mobile and web browser based apps like those you get on your phone, vs the more complex x86 apps on a PC. The advantage of a Chromebook is the hardware is simpler and cheaper, and costs a lot less. If all you're doing is surfing the web, using basic apps, and playing mobile games it's ideal. Chromebooks and Mobile tablets are good enough for 90% of non-business users or gamers these days. They cost less, weigh less, have less parts to break, and the batteries last longer. If you want to play PC games, or need to run stuff for work chances are a fully fledged PC will be better. But the line between the two is blurring more and more every year."
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m7govv | How come two pictures that are the same size and taken with the same camera can have different file sizes? | Technology | explainlikeimfive | {
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"Compression. The camera saves storage space by compressing the image, and how well that works depends on how detailed and sharp the image is. The more information there is in the image, the harder it is to shrink down in size.",
"Different amount of detail in the picture. A picture of some white animals on snow is going to have a lot less detail (and a smaller file size) than a picture of a bunch of cosplayers standing in front of a Tokyo neon-lit street. The way images (a JPEG, for instance), are saved, more detail = larger file size. [This is a pretty good breakdown of the how and why.]( URL_0 )"
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m7hafr | What causes a computer's software to "stop responding", and why is it specific to certain tasks? | Technology | explainlikeimfive | {
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"Software operates like baking a cake. You pull together all the ingredients. You find a bowl to mix everything in. And after everything is prepared, you fire up the oven to bake the cake. When you open up a Save As / Open dialogue box, the operating system these days shows you a snapshot of the file system. This is like you trying to put some silverware back in the silverware drawer. Instead of everything in the silverware drawer being saved anywhere, when you open the drawer, it first loads up the drawer, then it loads up everything inside, one at a time. Now imagine that you're standing in the kitchen again, working on baking that cake. When you're focused on preparing everything, life is good. If you suddenly divert your attention to washing the dishes, the cake process stops while you figure out what you need to wash the dishes. Now imagine that you started washing the dishes but decide to make a sandwich. The cake process and dish washing process are still active and taking up space in your kitchen which means less space to work with while making a sandwich. Likewise, after you open up a few programs, there will be less space (memory) available for additional actions. Once you run out of space either in the kitchen, or if you see that you're trying to do too much in the kitchen and mentally break down, that's the same thing as the software's message of it not responding. As for the second half of your question for why it's specific to certain tasks, think about everything you do in the kitchen. Some tasks take lots of prep and work like baking a cake. Others are nice and simple like pouring a glass of water. You can pour yourself a glass of water all day and have no issues pouring a glass of water. If you try to prepare a complex recipe, you'll need to dig all over to pull all the necessary ingredients together for that recipe. If you try to prepare a complex recipe on another day, you'll still be stuck pulling ingredients and supplies from all over."
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m7ih1h | Why does military communication quality suck while my mobile can produce actual sounds? | Technology | explainlikeimfive | {
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"text": [
"Your mobile would suck if someone shot a missile at your cell tower. Also you probably wouldn't get mobile reception in the middle of an active warzone (possibly due to missiles/mortars/insurgents with hammers). Military coms often can work without cell towers, but you're stuck talking radio to radio rather than having a big tower full of electronics equipment to help out. Also there's encryption to prevent the enemy from listening to what you say and sending you incorrect orders. Finally, the radio was probably designed in the 1980's and never updated because they couldn't find a mobile that could take the punishment while being cheap enough."
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m7j1v8 | What is an alternate reality game defined as? (ARG's) | And how does it different from augmented reality? | Technology | explainlikeimfive | {
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"Augmented reality is augmented or changed/added to. Typically it involves a layover by looking througj some kind of glasses or tablet or such, where computer graphics will overlay against a real life background. Pokemon Go is a good example. You can see the pokemon against a real world background using technology. Alternate reality is akin to roleplaying where the game takes place using the real world. For example, it may involve solving a puzzle where clues are posted through sources like radio signals or websites that appear to be legitimate, not just \"part of a game\". In this sense, you're \"changing\" the reality we experience, altering it to make it something else. Often times its not initially explicitly stated to be an ARG and the air of mystery is what makes it interesting. Clues will be left for people to pick up and be curious about, leading them on a hunt for more. It'll just he this weird thing and they don't know what it is till the stumble through it. Its often used as a form of viral marketing."
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m7jxoz | How does ownership of TV air time work? Do the broadcasting channels like ABC, CBS, or FOX own the specific channels? What would prevent me from having my own channel to broadcast whatever I wanted over the air? | Technology | explainlikeimfive | {
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"In the US, control over broadcasting frequencies is through the FCC. Each broadcaster is awarded a certain frequency to broadcast on. You will be prevented from broadcasting over the air. It would be impossible to broadcast and not be detected and the location triangulated very easily.",
"Broadcasters are licenced to use certain bands of the broadcast spectrum. They pay the Govt for such licences. When detected, penalties in law would be used to prevent the unlicensed broadcaster from continuing. How would they know? Well, if you were to broadcast at exactly the same frequency as an established brand, it won't take long for their regular viewers/ listeners to complain about the interference with their regular programming...."
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m7w8l6 | Worksheet that is "Illegal to post on Internet" | Technology | explainlikeimfive | {
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"text": [
"You can’t post the entire text of Harry Potter online for people to download because it’s covered by copyright laws. This section of a digital math textbook likely is as well. You can’t own math of course, but you can copyright specific text of questions and answers that you have written.",
"if not human decency then in this case at least copyright law. while you cant copyright the problems themselves, you can get a trademark/copyright for the composition.",
"Copyright law is what's preventing you. Technically, it prevents you from posting it anywhere. You're not allowed to make a copy unless you have a license. You could be sued for copyright infringement."
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m7y711 | how does motion capture work? | Like when an actor does things, does the animating team have to still animate it, idk how to explain it. | Technology | explainlikeimfive | {
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"For most professional mocap, the actor wears a suit with special markers at key points on the body. As the actor moves, a camera records them and feeds it to a program. The program then creates a 3D 'skeleton' of the actor moving around - the markers help the program identify keep points on the body. The animators can then layer textures on top of that skeleton so that the end result is animated, but it has realistic motions (because the skeleton is a recording of the actual motion)."
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m80gqq | How does cellular data work? | Ok I get it sends a signal to my device, but how does it know the specific data I want? Also, how does it find my specific phone when I receive calls? | Technology | explainlikeimfive | {
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"The cell tower doesn't know what specific data you want, any more than the post office knows what's inside your mail...it just knows it's got a \"packet\" addressed to you and it delivers it. Your phone is the one making the requests and processing the receipts. As far as knowing where your phone is, as long as you're connected to your network, you've got an active radio connection to the \"nearest\" cell tower (\"nearest\" because it's really the one with the strongest signal, not necessarily physically closest). When someone calls you that request goes into your phone company's network. The network says \"Right, which tower is talking to number XYZ?\". If you're on the network, one of the towers will say, \"Me!\" and the cell network routes the call to that tower. Then the tower sends a radio signal to your phone saying, \"Call for you.\" The tower already knows where you are (in a \"which antenna\" sense) because your phone is always maintaining a connection."
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m82bh5 | How do some electronic devices (phone chargers, e.g.) plugged into an outlet use only a small amout of electricity from the grid without getting caught on fire from resistance or causing short-circuit in the grid? | Technology | explainlikeimfive | {
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"Electrical engineer here: Low powered devices do the opposite of a short. They have such high resistance that they only let a small amount of electricity through.",
"Devices only take the power they need. Like a firehose, you could use a whole lot of water if you open it all the way, but your phone charger only needs a little bit of Power, so it's like opening it up a tiny bit. A trickle comes out. Even through there's plenty of water pressure available. The fire hose is the main power to your house. Your outlets are like garden hoses, they each can't let out nearly as much power as the main power line, but they're all connected to the same main location (your fuse box)",
"My (non-electrical engineering) understanding is that newer alternating current (AC) to direct current (DC) transformers (which change the voltage of wall current to something lower voltage that digital devices can use) work by only using a little bit of current from the short period of time when the voltage is starting to go up and down in the AC cycle. As such, they don't use resistance (which would make heat) to change voltage. A part of the device called a rectifier switches the positive and negative parts of the cycle so the current is only running in one direction (DC). Then capacitors smooth out the current so it's basically constant.",
"Electricity is like a water supply in a closed loop (from live to neutral, or positive to negative, say). Voltage is a \"pump\" pushing water through that loop. The wires are pipes. If the pipe is small and constricted, only a small amount of water can travel through it. If the pipe is large, a larger amount of water can travel through it. Low voltage devices, by the design and nature of being low voltage, are all very thin pipes. High voltage devices are very fat pipes. Now if you push hard enough, obviously the small pipes would burst first, but that's not how electricity works in practical contexts. We push at a very standardised pumping rate (voltage). The items we design are designed to always cope with that \"pressure\" without bursting (otherwise everything would be on fire!). Given that we know that pressure, and design all our pipes to cope with it, our pipes cannot burst. They might get very, very thin or very fat, but they're designed to cope with the pressure of 110V or 220V. However, if you make a pipe like that, and its very narrow and thin, there's only so much water that can pass through it every second (the power). If you make a pipe fat, more power can go through it, even though you're only pushing with the exact same pressure. The size of the pipe you make determines the power that the device gets / uses. And you never design it such that a pipe is so weak that it could \"burst\" (e.g. a wire burning out) or put more pressure down a pipe than it's designed to handle (e.g. 440V down a 110V cables) because then that's a fire hazard. But it's the size of the pipe that matters. And phone chargers only have a tiny pipe, and the electricity company only ever pushes with a certain amount of pressure, so only a tiny amount of power ever goes through them. So long as that pressure stays the same, the pipe never bursts, but less water goes through the little pipe than through the bigger one that's fed from the same supply pressure (the same way that you can run a dribble from your tap and your neighbour can run a huge hose from the same water supply, and it doesn't BURST out of your tap when he does that)."
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m84egn | How does regenerative braking work? | Technology | explainlikeimfive | {
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"Electric or hybrid cars have electric motors and batteries. Electricity flows from the battery into the electric motor to make the car move. The opposite also works. The electric motor can convert motion into electricity that is put back in the battery. So regenerative braking does exactly this. It converts the energy of the car's motion into electricity. As it does so, it slows the car down, because that motion energy is being consumed to generate the electricity."
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m865k7 | How do password manager work? What is the best one and does it work on mobile as well? | Technology | explainlikeimfive | {
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"text": [
"Password managers are a secure vault to store your passwords and other sensitive information in. They work by storing your usernames and passwords in a way that can be retrieved easily, provided you remember the master password. The master password is used to decrypt the vault so that the information within it is accessible. It is recommended to have a two-factor authentication method configured as well. This means that you’ll need both the password and a code that is generated by an app or physical token. When the code and your password are paired together, the vault is unlocked. There are many options available. You can read a non ELI5 explanation on them at URL_0 They recommend Bitwarden as a solution. There are Bitwarden apps for MacOS, Windows, Linux, iOS and Android, plus a web interface. Bitwarden is open source, which means anyone is able to review the source code and determine if there are flaws. In summary, a password manager enables you to have very complicated and unique passwords for all of your accounts without you having to remember each one."
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m87u3y | How do computers and phones keep track of the date and time, even when they're completely shut off? | Technology | explainlikeimfive | {
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"They're not completely shut off. Computers will have a small battery called a CMOS battery. It keeps the clock running, among other things. I don't know about phones, but I imagine they pull a tiny amount from the battery to keep the clock running.",
"On PCs, on the motherboard, there is a small battery called a CMOS battery that provides a small amount of power even if the pc is unpowered :)",
"They are never completely shut off. A dedicated circuit, the Real Time Clock or RTC is always powered on, usually through its own dedicated battery. The RTCs only job is to keep track of the time.",
"One correct answer is that they are not completely off, which has already been said. Another correct answer here is that smartphones and computers use the internet to tell time. So as soon as it connects to wifi or a cell phone tower or something like that, it will adjust it's clock accordingly. This can happen for some cell phones before they even display the time. So it has already been corrected before you see what it thought the time was when it was off.",
"Cell phones are connected to your providers network. Atomic clocks at the local phone office keep time for the entire network. [What You Should Know About Stratum System Levels ( URL_1 )]( URL_0 )"
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m8b2qb | What is a plasma tv and why were they so popular but have now been forgotten? | Technology | explainlikeimfive | {
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"Plasma TVs work by using panels made of millions of small gas cells (think mini fluorescent light bulbs). These panels are relatively difficult to manufacture. They were very popular because they had superior performance than comparable LCD TVs at the time -- with deeper blacks, more accurate colors, wider viewing angles, and less motion blur. But over time, LCD TVs became much simpler (thus cheaper) to manufacture than Plasma TVs. Plasma TVs also required more electricity to run on. So Plasma TVs began losing in popularity to the cheaper LCD TVs. What finally killed Plasma TVs was the introduction of 4K \"Ultra High Definition\". Turns out, making 4K Plasma panels for 50-60\" TVs would have been incredibly expensive. Because of this high cost, TV manufacturers decided that they would be better off selling 4K LCD TVs instead of Plasma, and invest in newer technologies like OLED.",
"A plasma tv is tv that uses little gas cells that light up when you flow electricity through them as pixels. Imagine neon (and xenon, and argon, but everyone just calls them all neon) lights, those tubes of gas that like up colorfully when electricity flows through then. Now take those, shrink them down super duper small, making little gas cells, and that is how you make a plasma tv pixel. It’s hard to say exactly why the disappeared. The true reason is because the companies that made plasma TVs announced that they were going to stop making them in 2014. While we probably won’t know exactly why those companies made those decisions exactly, it’s safe to say that they found reasons to prefer making LED TVs over plasma ones.",
"Plasma TVs produced a slightly better picture, but the quality difference wasn't worth the downsides for most consumers. So the sales figures never matched LCD screens, eventually leading manufacturers to abandon the technology.",
"They are what others described. The reason they were discontinued is because of the cadmium ban, which made good quality phosphors, and CRT/Plasma screens impossible. The CRT and Plasma screens were still sold in \"third world\" countries for some years afterwards.",
"They came right in the transition to big (32\" or more) and there weren't much LCD of that size Contrast and grey scale was far **superior** (LCDs were dim and no so good for B & W content) Still you can spot'em on tv news shows (small local) they have a **black stripe all around** inside the panel... so they competed and LCDs won for price , size (eventually) and life expectancy.",
"I miss the great blacks and refresh rates of the old plasmas. And the glass screens made the picture look better. I guess plasmas were the last flat screens available before LED made TVs cheap and disposable. Happens with a lot of products I guess."
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m8cpjm | why do computers get slower over times even if properly maintained? | I'm talking defrag, registry cleaning, browser cache etc. so the pc isn't cluttered with junk from the last years. Is this just physical, electric wear and tear? Is there something that can be done to prevent or reverse this? | Technology | explainlikeimfive | {
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"It’s not really really getting slower, it’s mostly the fact that new software is developed for never faster computers, so they will run slower on older computers, and as apps get updates over time, they will run slower and slower As an analogy if your computer is a car and the road is the software, it’s not your car getting less powerful, it’s the road getting steeper",
"They don't, they run at the same speed throughout their operational lifetime. You're just making them do more that they weren't doing before. As an IT professional, programmer and system admin please: \\- Stop defragging. It does basically nothing nowadays, certainly nothing worth the disk wear or the time it takes. Defragging is a handover from the days of 20Mb hard drives on older filesystems on slow-latency hard drives. Just stop it. Especially if you have an SSD - you're literally just wearing the SSD away, for no reason. If you want to avoid the need to defrag, don't run your hard drives more than 90% full, that's when things start to fragment to jam them into the gaps. If your drive isn't more than 90% full, it'll sort itself out and likely will never fragment in the first place. And modern PCs will basically not noticeably slow (even on a benchmark measurement) just because they're slightly fragmented. \\- Registry cleaning - again, does nothing. The registry on an average machine is maybe 50Mb-100Mb or so? Pathetic by modern standards. Cleaning it does nothing. You can remove services and auto-start entries, but use a proper tool for that, not some pay-for junk off the internet, or in the registry itself because if you cock it up, your computer won't boot properly. Sysinternals has Autoruns available to you for free, but pretty much most of what it does you can do with Windows 10 task manager, etc. on its own. \\- Browser cache - again, does nothing. You're just making the problem worse. Modern browsers manage their own cache and clearing it out makes nothing faster, just the opposite. Unless the page you are loading is not the page you expected (i.e. it's not up-to-date), cleaning your browser cache is entirely the wrong thing to do. What you want to do: \\- Make the computer do less. Have less programs installed (no, it doesn't matter how full your disk is, it's to do with how much stuff is running all the time). Get rid of anything you don't need to be running 24/7 (e.g. get it off your taskbar, stop it running with Windows, or stop it staying around all the time - it'll still work when you actually need to use it). Steam, for example, does not need to be in your taskbar 24/7. Stop it, using the options in the program or Autoruns. Then when you want to play a game, you run Steam. Personally, about 4-5 taskbar icons (by the clock) I find annoying. I work to get rid of them. Almost all of them can go. The Intel display one (unless you think you need to use it), nVidia icon, Java, Steam, printer monitors, etc. etc. Get rid of them. The screen will still work, your games will still work, your printer will still work. But you're not constantly running them 24/7. There are also dozens of services, programs that run on startup, and other junk that's always running that don't need to be. Almost all third-party program services (e.g. game launcher services) can be changed to manual startup (and then they will start if they're needed, but won't if they are not). Uninstall stuff you don't use. Your machine is no slower than the day you bought it. It's just running all the shit you installed on it for the last few years and never removed and which is running 24/7 even though you don't realise or don't even use it any more.",
"It's a combination of factors: More tasks / software bloating - The strongest of these is that normally you are asking your computer to do more tasks than before - some of this is subtle stuff brought in with Windows Updates and especially Chrome updates. Chrome started nice and efficient and a hell of a lot faster than Internet Explorer but has slowly gotten fatter and fatter. But it's not solely the browser's fault. As PC Processing Power, PC Memory, Browser Stability and internet speeds have all generally increased so websites have gotten more and more resource intensive (especially with the copious amounts of various advertising they force on you). The same holds true for a lot of software out there - that as PCs become more powerful so the software changes to leverage more of that power. Security, security, security - A HUUUGE part of OS, browser and software updates is security based. It's very, very seldom that security updates result in increased speed or performance. Failure Rates - RAM, CPUs, GPUs, HDDs, SSDs all have failure rates and these tend to get worse over time especially if there's significant heat in your system. I not talking total failure I'm talking bad sectors, I'm talking memory parity errors. Modern day OS and firmware do an immensely good job at handling this invisibly. Often you may not be aware that you have bad sectors at all. The sector has been discretely marked off limits and a replacement sector has been allocated. But when that happens it's basically introducing a permanent fragmentation onto your drive. OS / Registry scarring - Back in the good of days of Windows 98 it was a pretty regular thing to reformat your system at least once a year - sometimes due to a complete OS crash - but often wanting to have a clean version on because over time you add and remove programs, you get the occasional virus, you run registry cleaners and you install a ton of updates and well as any tinkering you may have done yourself in the registry. This all leads to the registry and system files not functioning as well as it should. Registry cleaners are a mixed bag - they spot a lot of problems but their solution is to delete the problems. Top Recommendations: Antivirus - check that you only have one anti-virus on your system and that's it's not McAfee. Multiple antivirus apps will interfere with each other. These days Windows Security is an excellent choice for your antivirus needs. Switch to an SSD - If you haven't switched yet and you can afford it I would highly recommend it. It's faster and doesn't suffer from fragmentation (assuming you don't live with your system drive 99.95% full). HDDs are still good for storage drives by your system and games should be running off an SSD. Clean install - Especially if you've upgraded between windows versions or even between major builds you will be surprised how much better your PC will run on a fresh system. This goes well with upgrading to an SSD. Download the USB installer from Microsoft's website and get a completely fresh version of Windows with no manufacturer bloatware on it. Do make sure tht you've backed up EVERYTHING you need: files, passwords, websites. Remove software that you're not using - especially any software that installs it's own services. I try where possible to use portable versions of applications - that way you know that they're not cluttering up your registry, system files and services. Also always check if there isn't a windows app that does what you want already. Hosts file - Use your hosts file to block advertising sites - this is fairly technical and I don't recommend for the average user but it's preferable to using ad blocker software. It's a fast, nasty but uncomplicated firewall essentially. What I do when I find a website that's running slow it I analyze that particular website on [ URL_1 ]( URL_0 ) \\- I identify the external links which are causing delays and block those via my hosts file. Upgrade you memory - definitely these days if someone has only 4gigs my instant recommendation is upgrade, upgrade, upgrade. Running Windows 10 you want 8gigs minimum.",
"Another good one nobody seems to have mentioned. Dust. Give your old pc a good Hoover out occasionally. Make sure it has good air flow, clean the fan and the filters if it has them.",
"PC's can slow down only a few ways. 1. Electronic failure. Parts can break, but on a PC most components that break will prevent it from working at all. The exception is a hard drive or a fan, which are the only two parts that can slow down over time. 2. Hard drives. Hard drives can slow down as they fill up, get erased, and rewritten. Your computer knows where files are, but imagine reading a book where each word is on a different page in random order. You have to flip back and forth to read it. This problem with hard drives can be fixed with a format and reinstall. A drive known as a \"SSD\" can also help prevent this from happening as much. 3. Heat. With the death of fans, your computer can overheat. Your computer tries to prevent this by using less electricity, and running slower. This can be fixed by cleaning, or replacing broken fans. Sometimes other measures like new paste under the cpu cooler can be required. 4. Software. Software can be added and added, slowing down your computer just like the car weight analogy. Sometimes removing the program leaves behind traces which still slow down computers. Most techies call this \"bloat\" or \"bloatware.\" A format and reinstall can fix this. This is the most common way PC's \"slow down\" over time. Edit: it's important to note that generally PC components like processors and ram never slow down. It just seems like it over time because of other factors. A good clean, a new SSD, and your PC will run just as good as new, at least for the vast majority of cases.",
"Newer versions of software is written for newer faster hardware, so sometimes it asks to do a lot more stuff at once, which can be taxing on older systems. Unfortunately, there's not a lot you can do about that other than trying to tell it to stop running so many background. So even if your computer hasn't physically degraded at all, it's slower than it used to be.",
"Check your task manager and see are any programs hogging cpu, memory and disk. Check the temperature of the hard drive, SMART data and temperature of the onboard components. If it is a laptop and things are hot swap out it's thermal paste and clean it.",
"5400 rpm hard drives. Companies love to install them in inexpensive computers. If it doesn’t have an SSD, don’t bother. Win10 updates on a spinning disk is the “death” of a computer.",
"The thermal paste drys out, and heat fins clog up with dust. That makes the chips run hotter, and they slow themselves down to produce less heat.",
"Take a look at [Bill and Andy's Law]( URL_0 .) Basically, software gets more complex over time to take advantage of new hardware. If you don't upgrade the hardware, the new software will just take longer to run.",
"Windows user profile is a big cause. It stores all the user customizations, and basically loads it all up whenever that user logs in. The way windows works, there is no easy way to reset an old profile back to new. So create and use a new profile on that \"slow\" computer. Voila! Much faster now~",
"The only real answer is that your computer does not get slower. It can't. Aside from some actual hardware problem. It's just becoming less capable. It's the equivalent of thinking a pocket calculator would become slower over time. Follow up question. Who on earth is still using a computer with a HDD? I just bought a 1TB Samsung SSD on Amazon for $109. You can get a 250GB for $30 tomorrow. More than enough to run your OS and frequently used programs. Also. All third party Anti-Virus software is worthless for a single user home PC. Worthless. They just steal CPU crunch time and RAM with zero ROI. Windows defender is enough.",
"Computers don't get slower. They stay exactly the same speed. What changes is the software. Software continues to use more and more resources. which means older hardware takes longer to run newer versions. These days the amount of resources things use is a little crazy. Just opening up a web browser and surfing the web for half an hour will take up like 1-3 GB of RAM depending on what web pages you go to. For reference the computers that NASA used to do the calculations for moon landings had 32 KB of RAM.",
"Registry cleaning and other stuff doesn't solve all problems completely. Some errors still remain, some junk still accumulates, more software is installed/updated over time and this new software is often \"heavier\" and slower-working than older versions. If you format a drive and do a clean reinstall of the system with (optionally) only the old versions of the software it had at the start, it should work faster again.",
"In general, the answers here are correct but a big mistake is assuming it to be true. Computers can get slower with time. SSDs get slower by lack of trim or by the aging cells. Processors also get slower as time pass because the cooling gets inefficient with time, by dust, old motors or even old thermal paste. But in general, what makes a pc old is the new software who is programmed with more resources in mind.",
"It's mostly a Windows issue in my experience. When W10 was forced on my very old low end i5 laptop it took 5-10 mins from button press to chrome displaying a white page with no content. I installed Manjaro Linux and it was faster and more responsive than my developer-grade i7 work laptop. I rescued repeated this again with Ubuntu Studio Libux on another laptop with the same result. That being said, when talking about application performance, they keep getting bigger and more complex. You also adjust to your new pc's performance, making that the new normal for you.",
"If you do a clean install of Windows it will be as fast as the day you bought it. But after you've downloaded all the updates and installed all your software again, you'll pretty much be back to square one. As others have noted, it's the software getting bloated, not your PC getting slower.",
"I just want to add a quick comment about framentation. It will make your harddrives with spinning disks get data slower. This is because of the read head inside has to move more to access all the parts of files. In solid state media there is no read head, therefore it doesn't care about fragmentation.",
"Mostly, it’s not slower. There are three major points to consider: -The software side, if you keep installing more and more programs that do stuff when the computer turns on or while it’s running - this will effect performance (which is why a clean install of your operating system will often offer a tangible performance boost). -For hardware, clean the dust from your pc so that thermal throttling doesn’t occur. Most of the components will have suffered negligible performance degradation. But if they’re unable to maintain the temperature they were manufactured to operate they will throttle themselves so that errors and damage does not occur. -hardware is constantly evolving and software becoming more and more complex with it. What was good ten years ago is mediocre at best now. A top of the line system back in 2011 is about as powerful as an entry level system is now. So relatively speaking, the old computer will feel slow.",
"Some of it is perception, but a lot of it is due to mechanical hard drives. I can guarantee that if you replace the mechanical hard drive with a solid state drive, you will experience an immediate 3-5 times boost in performance for the system booting, programs loading, and so forth. , Also memory requirements gradually climb over time so that more and more installed memory is needed for the system to run smoothly. If you do not have enough installed memory then Windows is forced to do something called paging which involves moving infrequently used data out of memory and onto the disk so that programs have enough free memory to function. Even back in the days of Windows XP, 256 meg of memory was just not enough and the system would regularly run horribly slow because it was constantly paging out what little memory was available to the slow mechanical hard drive, to try to shoehorn everything into a tiny amount of live memory. * Around 2000, about 512 meg of memory was enough. * Around 2005, about 1 gig of memory was a good amount. * Around 2010, about 2 gig of memory was enough. * Around 2015 about 4 gig was enough, and people started moving to 64-bit operating systems. * Now around 2020, about 8 gig is the expected minimum, and 64 bit is the standard for operating systems. I am expecting this to continue, and it may accelerate towards 2015 that 12 to 16 gig will be the expected minimum. Any new computer that I buy now will have a minimum of 16 gig installed, AND at least 1 expansion slot open to grow this to 32 gig by 2030. , A similar minimum growth is occurring with the Windows boot drive for an average work computer where someone is doing minimal or no video editing. Back in about 2015, 128 gig was an acceptable size for a boot drive for a typical business desktop or laptop, but this has gradually grown to about 256 gig now. Part of this is related to the increase in memory storage, because Windows generally likes to have both a virtual memory page file and hibernation file that are both about as large as all of your installed memory. * Windows 10 by itself wants about 30 gig of storage. * If you have 16 gig of memory, then except to have at least 16 gig used for the page file. * And another 16 gig for the hibernation file. * Windows Update likes to hold onto a cache of installed updates so that they can be removed if there's a problem. * When Windows Update does a \"release upgrade\" it is essentially installing an entire new copy of Windows and the previous version hangs around for at least a month, consuming 10-20 gig. All of this plus a few installed company desktop programs rapidly ends up consuming 75-100 gig of storage, so a 128 gig solid state drive just doesn't cut it anymore."
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m8hpj3 | Why do liquor bottles sometimes have those thing that make it pour really slow? | Technology | explainlikeimfive | {
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"They are to measure the fluid. Barkeepers need to measure a lot of fluid in as short of an amount of time as possible. I don't know the exact figure, but they pour at around 1cl per second, so if the drink asks for 2 cl you pour for 2s. That is much more accurate than having an open bottle and just guessing how much you pour.",
"It that has to do with being able to control the pour, so you don't have the giant air bubbles (since a lot of those bottles have long narrow necks) and not filling the glass too full. Since most hard liquor is meant to dolled out in fractions of an oz to maybe 2 oz. I can't remember the exact size of the jigger and pony.",
"This is a bit broad. Are you referring to pour spouts as seen in bars and restaurants, or the plastic built into the opening of large bottles?",
"Posi-pours have a ball bearing that stops flow after a specific measure is poured. These can help insure consistent mixtures, and speed up service.",
"If you're talking about those whitish plastic things, they can be popped out pretty easily with a knife in my experience.",
"All these comments talking about measuring are either thinking of something else (spout) or just wrong. The plastic thing is an anti-tamper protection so nobody can tamper with the drink, like dilute it with water or fill it again with moonshine to sell as the real deal. Cheers."
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m8lo2t | - Could we add some type of air compressor and blower system to clear solar panels and extend the life of planetary probes? | Technology | explainlikeimfive | {
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"Yes. However the degradation of the panels is planned for during the engineering design phase, and it's cheaper (and less launch weight) to simply oversize the solar panel than it is to add a complicated mechanism (~~air~~ atmosphere pumps don't have infinite lifetimes, and abrasive dust is also a problem: you can't just add a dust filter to the pump intake because it would eventually clog). A brush on the solar panel would seem like a good compromise to me, but perhaps it would eventually erode the surface of the cell (again due to the abrasion from dust).",
"In theory: yes. If there's anything to compress you could do it. In practice, so far it's been deemed not worth it. On Mars it turns out there's enough wind to keep the panels somewhat clean anyway. So why not go the easier way and just make a bigger solar panel instead? This way you avoid all the fiddly moving parts of a compressor, and don't run a risk of it say, blowing up. Also a rover has a weight and energy budget, and using that on the compressor may well mean passing on something else that could be more useful. Opportunity was planned for 90 days and lasted 15 years. Spirit lasted for 6 years until it got stuck. Curiosity and Perseverance are nuclear powered and don't have solar panels. All in all it just doesn't seem to be a problem that needs solving."
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m8qb0l | What exactly is stopping me from making 20 email accounts and referring all of them using paid survey sites/apps to get loads of points? | Technology | explainlikeimfive | {
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"Nothing. Typically those sites/apps have some requirements meant to curb it and make inconvenient though. Such as minimums balance for payout, spend a certain amount, or wait an amount of time. Additionally, many of those sites pay terribly, you're better off just doing an actual job than trying to get points. So, in summary, you can, but it's not worth it.",
"Time. This is actually a thing, its always been a thing, its generally not something most places care too much about, they aren't going to go through the effort to try to defeat this tactic that will cost them a lot of time and money to implement when its an extremely small inconvenience at best. There are various ways to attempt to prevent this, and likely they will have at least some safeguards in place, its just not a big deal to go overboard on prevention of this, you're better off just working on running your company. If people want to find ways to navigate loophole or piracy, they'll eventually figure it out. Put some basic security in place and worry about the rest of your product, not like 3 guys doing something awkward when you have a customer base of 100,000 people. To take it to another level, a lot of time, \"free trial\" stuff people just rotate around email addresses and such over and over, but eventually it just gets to be a burden enough that most people stop doing that. Its something that is more common to find in developing countries where there is more willingness to continue spend time and effort to find loopholes"
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m8udfc | what exactly is disk defragment on computers do? | Technology | explainlikeimfive | {
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"Imagine a messy room where everything is thrown all over the place and u have to run to different places to get everything u need. When u defragment the computer is putting things back where they are supposed to be so it's easy to find Edit my best explanation: Pretty much. If u haven't defragged in months you will usually notice a speed boost when opening things. Imagine u have a messy room. U want to play monopoly but instead of putting everything back in the box, u just literally threw it into your room. And stuck the box on a shelf so u know where it is. Now when u want to play monopoly u got to search through your messy room looking for all the pieces. Each piece tells u where the next piece is, but u still have to go-to that spot to find it and the instructions where the next piece is. Sooo u always know where the box to monopoly is in ur room. The box tells u where one of the dice is, that dice tells u where a chance card is, that chance card tells us where another chance card is, which tells u where boardwalk is, which tells you where the board is etc etc etc. So ur running around diging through things playing treasure hunt just to play monopoly. Defragging puts all the pieces to monopoly in the monopoly box on a shelf where it is supposed to be in the room."
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m8vq5x | how do sounds travel down a phone? How is it the noise from my voice is transported and heard miles away? | Technology | explainlikeimfive | {
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"A phone is two parts, a microphone that records your voice and a speaker that plays back the voice from the other end. A microphone works by having a tiny diaphragm that moves back and forth when a sound wave hits it. There is a coil of wire attached to the diaphragm and a magnet surrounding the whole thing. When the coil of wire moves inside of the magnetic field, a current of electricity is created in the wire. This current is amplified and sent down the electrical wires all the way to the person you are calling. On the other end there is a speaker in your friend's phone that works the opposite of the microphone in your own phone. The current of electricity causes the diaphragm to move inside of the magnetic field and it recreates the sound wave that was originally your voice. Modern phone systems have a few extra steps where the electrical current is measured and converted into a digital signal. That digital signal is what is actually transmitted over long distances but it's converted back into an electrical current before it reaches the speaker on the other end.",
"Sound is converted to voltage on a wire. The changing voltage is digitized into a string of numbers. The numbers are sent to the other end of the call where the process is reversed."
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m8ydwb | What is special about some bricks and charging cables that make my Google pixel 2 phone "rapid charge"? | Some brick/cord combinations make it charge but not say "charging rapidly" and others make it tell me it's charging slowly and I should use the ones that came with it. | Technology | explainlikeimfive | {
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"Fast charging requires a device and charger that are rated for higher amps. Amps is essentially a measure of flow, more amps mean more electrons moving. The device determines if it can fast charge or not, but it needs an adaptor capable of delivering the extra juice it needs. I've actually heard a bit recently that fast charging does have a negative effect on the longevity of the battery. If you have multiple chargers, some fast and some slow, it's better to use the slower chargers overnight and save the fast chargers for times when you really need them. I bought one of [these USB charging monitors]( URL_0 ) a while ago and it's kinda cool to see what your USB chargers are actually doing."
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m917re | Why is it common to see Intel or AMD processors in computers, but no other brands? | Technology | explainlikeimfive | {
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"Those companies have the infrastucture, technology, and knowledge to manufacture processors on computers.",
"Motorola used to be a big processor manufacturer. The Apple II and early Macs ran on their processor. PowerPC was a collaboration between Apple, Motorola and IBM. They could not compete with Intel in horsepower or architectural breakthroughs. Also, Intel aligned itself with Microsoft early on and MS flooded the market with their OS, both personal and enterprise, consequently making Intel an ubiquitous processor. AMD emerged later, and mounted a successful challenge to Intel. Apple just released their new line of non-intel Macs last year, because iirc Intel processors run too hot and consume too much power. They are back to being a player on the market but they are limited by the fact that they are limited to the personal computing space and only used in their products so I doubt they’ll challenge the big 2 for the title.",
"It's very, very, very expensive to buy the tools and experts required to create processors. Thus, it is economically difficult to run a competitor. Source: Dad worked for Cyrix, back when that was a thing. It's also worth noting that the latest Macs don't run Intel or AMD, nor do Raspberry Pis, nor does any cell phone, and I don't know what the current generation of game console runs, but the previous generations didn't use them either.",
"There use to be other brands. I remember a company called Cyrex I think. And there were others. Back in the 90s. But they couldn't complete with Intel and AMD. So they either got bought up or went out of business. In current times Intel and AMD are codependent on each other.",
"A long, long time ago, I can still remember, there *were* multiple Chip companies: Intel, AMD, IBM, Cyrix, … and those were just those compatible with the Intel microcode (the low-level language that actually influences the tiny transistors on each chip). For a time AMD was actually ahead by delivering better thermal efficiency. But here are the problems: 1. If you try to be compatible, you'll always be slower to market 1. If one instruction set dominates the biggest market – consumers – it's hard to make money elsewhere Apple managed to do do their own thing for a while using Motorolla 68k & similar CPUs, and a lot of big iron still had their own stuff, like the HP PA-RISC or IBM with the System/360. But most developers folded, were bought, or moved to other niche chips. AMD wasn't doing so great either, but then they managed to do something that Intel hadn't done: create a backward compatible 64bit CPU & instruction set. Intel *did* create a 64bit CPU – the Itanium – but it wasn't compatible with its other chips and only meant for big servers. That did put AMD back on the board. The big hurdle for new players, at least in this market, is that you'd need to - create the CPU from scratch, and CPU design is not easy - be fast enough to market - have an advantage over both Intel and AMD (performance, thermal, price being the most obvious targets) - find a fabber (chip factory) to actually manufacture them So other systems usually play different fields: - VIA is stil creating Intel-compatibles, but for the Chinese market, probably with big subsidaries from the government - ARM licensed out their design, and those chips are largely used in embedded systems (though there is a growing market for general puropse machines, see Raspberry Pi & Apples M1) - a lot of energy is currently going to new RISC-V systems, an open source chip design - and then there are all the ATmega(-compatible) chips for embedded boards like the ESP32"
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m9330s | Why is physically hacking into game studio's servers the only way to obtain game's source code? | Technology | explainlikeimfive | {
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"When it comes to code there is an important distinction between high level code and low level code. Source code is the highest level code that is available for any written project. Afterwards you translate that code through a compiler which makes it low level code. High level code is meant for people to read. It has syntax that is recognizable to humans and is usually broken up into parts to make working on it easier. Low level code is meant for machines. It is the ones and zeros that tell your computer how to move the rest of the ones and zeros. When you download a game you are receiving that low level code. Its all you need to actually run the program and is far more optimized. The problem is that data is actually lost in the translation process. There are actually programs that attempt to rebuild source code based on machine code, but it can only do so much.",
"The copies distributed out to users aren't human readable code, rather, they are machine readable code that is the output of a compiler. Think of it as the recipe of a cake: you can't always determine how it was made from just having the finished product.",
"> How is it locked from accessing by user? It is compiled. That is it is sent to customers in a language only the computer understands and can logically execute. There are tools to decompile it, but they can't do so perfectly, they usually cannot recover things like variable names and code comments, making code, especially code of that size, very difficult to read.",
"Decompiling code doesn't mean it dumps the code outright, let alone a nice and neat editable format. Decompiling can get you the \"what\" and maybe *some* of the how, but that doesn't mean you'll just get a raw dump of the code as the devs wrote it. Programming is a language - in any given language, there are different ways of saying the same thing. Decompiling is a little like using Google translate, but backwards, except you understand the words that it produces but not what it means in any context. That context and grammer are what you need to make a sentence, and therefore hacks and all that. Edit - Programming languages allow a person to make something on a computer by using a more human-friendly language and interface to turn whatever it is into \"assembly\". Assembly is what the computer can understand directly - some say \"1's and 0's\" but that's just a term for the billions of transistors being on or off. Decompiling gives me a way to recompile that code again, but not in the same way as the devs did, and it's the \"how\" the devs did it that makes hacks and other stuff possible."
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m937jl | Why is it that some phones today have cameras with hundreds of megapixels but advanced DSLRs and Mirrorless cameras have only 64? | What are megapixels? How do they work? What is the difference between a 64mp mirrorless camera and a 24mp mirrorless camera of the same brand? | Technology | explainlikeimfive | {
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"Images are made up of squares of a single color, pixels. A megapixel of course refers to a million pixels, 64 million pixels means 64 million tiny color squares. > Why is it that some phones today have cameras with hundreds of megapixels but advanced DSLRs and Mirrorless cameras have only 64? Because not all pixels are made the same. A digital camera has a sensor, this sensor is divided into smaller sensors for each pixel. While phones can have higher number of pixels, the sensors that absorb these pixels are smaller and thus more prone to error. The sensors on the DSLR are not only larger, allowing them to absorb more light to avoid this error, they also take in more light because these cameras have bigger lenses to get more light. DSLR manufacturers just have little reason to join in these \"megapixel wars\" since their customers know more megapixels doesnt necessarily mean better."
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m94nch | Why are most cups and glasses designed with a smaller base and bigger top? | My first impulse was that it's easier to hold them like that, but it's also very common among coffee mugs that don't have handles and uncommon among large water bottles. It would seem like a larger base would make a glass harder to knock over, both because of a widened base requiring more force to destabilize, and because of the weight distribution. | Technology | explainlikeimfive | {
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"Aside from stacking, it's easier and more confortable to drink from a glass that widens to the top, than from a one that narrows, you'd have to tilt the glass and/or your head more to finish the drink.",
"Glasses are made larger on top so they stack well. This saves space and make them safer and easier to store and move around."
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m9715f | what can realistically happen if your IP address has been exposed? | Technology | explainlikeimfive | {
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"> What can they do with IP addresses? Send you a message that your router will then promptly ignore. You are sending your IP address to every single website you visit, it's inconsequential."
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m98b03 | How do touch sensitive lamps work? | I looked it up and it has something to do with capacity but to be honest I didn’t understand any of the explanations I found. | Technology | explainlikeimfive | {
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"There is a common electronic component is called a capacitor, and we use them because they are able to store a little bit of energy, and release it in a way that we understand very well. We can design a circuit with a capacitor that causes electricity to 'oscillate'. This means that it goes back and forth thousands of times a second, with the frequency of this being controlled by the size of the capacitor. We put part of this circuit just under the bit of the lamp that you are meant to touch. The reason that this is useful is that our bodies can actually act like a capacitor. This means that when you touch the lamp, you change the frequency that the circuit oscillates at. It's very easy to feed this into another circuit that can see when the frequency changes, and change the state of the lamp (on/off, or brightness). Touchscreens on phones use basically the exact same concept of your body's capacitance, which is why a water droplet can make your phone think it's been touched, as a water drop also has some capacitance.",
"Your skin conducts electricity. When you touch the lamp, it detects a change in voltage and uses that as a trigger to change the setting of the lamp.",
"Water is a \"polar\" molecule. That means it is slightly positive at one end and slightly negative at the other end. If you put it in an electric field, it will try to rotate. This stores a little bit of energy in the molecule. We call the ability to store electrical energy in this type of way \"capacitance\". And humans are mostly made of water! Put your finger in an electric field and the water molecules in it will try to move. A sensitive circuit can detect this *change* in capacitance and then react. That's how touch sensitive switches and most touch-screens work."
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m9dcmq | how do fireworks form those cool shapes? | Technology | explainlikeimfive | {
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"The add various shaped charges into the firework to achieve different effects, different chemicals burn brighter and in different spectrum than others so will have different colours and intensities. Longer fuses and packaging create delays for the explosions.",
"The fireworks designers know the physics and the chemistry and use that info to build fireworks that will explode in certain patterns(physics) and give off certain colors (chemistry) [ URL_0 ]( URL_0 )."
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m9umtt | Why do the individual frames of a video look blurry, while the video itself doesn't? | I was going through a video of a car looking for its license plate number, and I swear I can just about make out that it's a license plate in the video, but it just becomes a blurry mess the minute I pause on any individual frame. Is my mind making up details? Is the blending/compression of the video codec reducing detail? Or is it some combination of factors? | Technology | explainlikeimfive | {
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"Have you ever tried looking through a mesh wire screen and couldn’t get a good look at what was on the other side because too much was blocked by the metal screen, but if you move your head back and forth while continuing to look through it, the screen practically disappears and you get a fuller picture of what’s on the other side? Your brain is building the image of what you see not just from what is hitting your eyes in a single instant, but from a combination of what you’ve just seen and what you expect to see. Any series of images you see in a tight enough window of time kind of get smoothed together into a continuous image, instead of a series of individual images, which is why video and animation works. Part of that means that, while each individual frame could lack some degree of detail from, for example, motion blur, your brain will be averaging the information of several frames together to get a clearer picture of what it is that is moving than exists in any single frame on its own. It’s also possible that, depending on how you are viewing the footage, you aren’t able to scrub through it literally frame by frame, and some of the frames being skipped have more information in them than the ones being displayed to you. This is particularly likely if it’s a video being streamed to you rather than one saved directly to your computer."
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m9x55k | Do Ancestry tests like 23andMe misrepresent what genetics is able to objectively say about a person? | Technology | explainlikeimfive | {
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"No - but anyone looking at genetics need to understand that different tests have different qualities of results AND we know a tiny % of what our DNA codes for. On top of that, the knowledge both of genetics and the interrelationships between genetics and other parts of health are changing rapidly. If you’re wanting to make healthcare decisions use a modern clinical genetics test (not the 20+ year old tech from 23andMe) and work with a generic counselor. Ensure that the test and group you work with are regulated and part of the medical ecosystem and at a minimum get what’s called an Exome test.",
"Could you be more specific? They are private companies with a sales pitch, so you have to do your own due diligence. They both find relatives who are third cousins and closer pretty easily. Both try to assign nationalities. Those results can be a bit fuzzy. They aren’t bad when the percentage is at least an 1/8. I wouldn’t trust anything under 2%. That’s just noise. 23andMe adds whether or not you have certain markers associated with health risks. I’d ask a doctor how important or accurate this information is.",
"If you’re asking a legal question of these companies like 23 & Me ‘’misrepresent” themselves, that’s a question for /r/LegalAdvice. If you’re asking do they overstate the tests ability to identify genetic medical problems, yes they give a greater impression of what they can do by using words like “can” and “may.” I *can* guess if anyone has cancer and I *may* be right because with my binary guess at a large enough sample size I’ll get some right. If you want as accurate as possible a test for genetic markers for disease, then go to a doctor. If you’re asking is their schtick of telling you what percentage ethnicity/race you are, again that’s kind of accurate and kind of not. The machine doesn’t have a magical way of knowing, its just checking certain markers against the database and updating that when they know they have more data. If you want better accuracy than they offer, go to a professional who finds family history. Although, again, to a degree any fanily history can only be as good as what is already known and what public records ever did, and still do, exist. I know that isnt the best answer, but your question is vague.",
"I do genealogy and for me it is a great tool because I can make my tree fatter which also helps make it taller, as someone may have found a common ancestor's parent that I haven't been able to find. I have traced my family lines back at least until 1800s and I once went through it an figured out which countries each line came from. I had about 36% unknown origin countries. But based on how long ago they were in the americas I have a good guess on where they were from. So the result that I found in my tree are basically the same as my dna results. There are some things to that you may consider misrepresented. 1. At 7 generations or more you share 1% or less dna with a single ancestor so the result can't really tell you where your ancestors were 1000+ years ago. 2. The ancestry and 23andme do not have a lot of sampling from people who lived 500 years ago. So that means the results tell you more about where your ancestors descendants live now. Which might not exactly be the same as where they lived at one point. 3. Likewise the results can vary depending on who has taken the test. Like when I first took the test it did not say I had any ancestry from scandinavian. But now I have about 1% with more data points the tests are better able to be more nuanced. This is another reason that it would be nice to have more data points from people who died centuries ago but I don't see either company digging up graves. 4. There is a point in history where everyone alive today shares all of their ancestors. With math this point can actually be surprisingly early and genetics is supporting a 5,000-15,000 years ago timeframe. So at that point you would be related to about 80% of the people alive. The other 20% would not have surviving descendants. This makes ethnicity sort of moot. 5. DNA can be tricky. My results for traits said people with my genes are likely blond and have wisedom teeth. I have brown hair and I didn't have wisedom teeth or two of the next molars. But a recent study that was published found 50 new genetic locations for eye color. Ancestry and 23andme are likely only looking at one or two locations for certain traits. So the main genes that code for hair color likely are blond genes but since there are many other genes that also code for hair color they likely changed the end result. So if something like wisedom teeth that is pretty simple can have different outcomes than something more complex like ethnicity is probably not better."
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m9y15y | How is it that a given website/service provider seemingly doesn’t know your password when you create an account, but it still knows it when you are trying to change it and it says “You can’t use a previous password” ? | Technology | explainlikeimfive | {
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"The result of a cryptographic hash function is what is stored and compared when you entered the password. This ideally produces a unique output value for any given input, but the original input can't be figured out from the hash value alone. However, if you enter the correct input value, the hash value will match the stored value, indicating a matched password entry.",
"Your password is (hopefully) not stored by the service. They will add some random characters (called salt) to your password and then transform it into some data that looks nothing like your password ,using a cryptographic hash. eg: using the common bcrypt hash, the text \"password\" becomes: * $2y$12$5.a9GcsptRjdHuDxJZnFgOOpjVX7ESdPSsXQ7kA6SKyMfrVJGNv0O or again with different salt * $2y$12$Dh9IoY4KyLHMu8PjmUvdOuJ9rlIIEHEB4FuQKUV7ngy4mkbaiyOi. It (hopefully) should not be possible to work backward and find out what text created this hash. However, it is possible to determine if a hash is a \"match\" for a given password. This is what the service does, checks if your new password matches the hash for the old password. It's fairly time consuming (even on GPU) for a computer to determine if a hash matches a password. Not a big deal if we only need to do that when a user logs in. However hashes are there to protect against the event someone steals the entire password database. To illustrate this, I give you the hash for my reddit account password: * $2y$12$mZ7hep8QvCd5bu0hmVa8iuTIQ44cd4rvGpkPvotarRgx4dGmHajku I can do this safely because my password is not a common word or password. To \"brute force\" it out by testing against lots of strings, until you guess the right one, will take your computer about half a year or more. The purpose of the random \"salt\" is that you don't want the same password to produce the same hash twice. If the system does not use salt, then a pre-computed dictionary of hash keys for common passwords would allow a someone to quickly discover passwords for a large number of the users in the database they stole. Such a dictionary is called a \"rainbow table\" and is still used against many poorly designed login databases.",
"The website keeps track of your previous password hashes: which is a piece of data generated from your password that can be used to check if a password matches, but which can’t be decoded back to the original password. Because the hash can’t be decoded back into the original password, they genuinely don’t know what your password is. However, by checking the password you entered against your account’s previous password hashes, it can tell you if the password has been used before.",
"When you give then the password, they do some complicated math with it that's designed to be easy to do but almost impossible to reverse. This is called Hashing. They store the \"hashed\" password, but not the one you gave them in plain text. When you then want to log in they do the same math again and compare the result. This way they can tell if its correct or not. The same happens when you try to change your password.",
"To clarify what exactly a hash is, it's a one way function, where you can encrypt the data but not decrypt it. For example, say my password is ABCD. A way (a terrible way, but still a way) to hash is to assign each letter a number then add them up. So I can add 1+2+3+4 and get 10. This is not reversible. If I give you 10, my password could be DDAA, CCCA, etc. There's no way to tell exactly what it was. A good hash takes a while to perform (for a computer) and changes the output completely with small changes to input. Optimally, there would be no way to map the output back to any input, but hashes do get broken occasionally. The important thing here is that the password provider doesn't know your password. You type it in your web browser, and before any data goes out, it gets hashed. The hashes are compared, and if they match, it's the same password. You can think of a way to attack this by just having a massive table matching passwords to hashes. So I can take your hash and look it up in that table, and find your password. The way to counter this is just to attach some junk data to the end before you hash, called a salt. This makes that table useless, because you might have 'password' but you won't have 'passwordjgbrhsizjcufbrbskfif' in your table. A theoretical problem with hashes is that all inputs map to a limited output space, so there can be collisions. Multiple inputs map to the same output. This is bad, but unavoidable. With our hash function, you can see that if you just keep typing strings of As, you will eventually hit all hash numbers. For good hash functions, this isn't really a problem, as collisions are so infrequent it's essentially irrelevant, at least in the password management space."
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m9zmf9 | How is audio transmitted from my phone to my wireless earphones? | I understand that both devices are equipped with Bluetooth modules, but how the sound is able to play instantaneously baffles me. | Technology | explainlikeimfive | {
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"Fundamentally it is just a radio transmission of data from your phone to the earphones, but there is a reason it took years to go from radio sets to Bluetooth headphones. Those chips are doing a lot and the process is very layered. How do you account for all the other signals bouncing off walls etc? How do you encode the sound as data efficiently? What do you do if you lose a packet of data? How do you minimise the power usage so an earbud works for a whole day? And a bunch of other issues that all got solved and standardised one by one to produce what essentially seems like magic. But yeah, radio waves."
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ma01bq | Why are medical pill capsules usually white and some other colour? Why aren't they just one colour? | Technology | explainlikeimfive | {
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"text": [
"The color combos and imprints helps medical professionals identify and distinguish one medicine from another easily"
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maf076 | Why is a standard thermometer only legible from one specific viewing angle? | Technology | explainlikeimfive | {
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"text": [
"The actual mercury tube you see is very very thin. When you can see it, you are looking through a lens that makes the hair-width tube look much wider. Like any lens, it has a specific viewing angle."
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maf8z2 | How are MAC addresses generated for virtual or physical network adapters? Do they have to be globally unique and not reusable? If so, how is that guaranteed? | There are many types of network adapters, many different manufacturers, all on potentially huge internetworks. Adapters get removed, changed, and added all the time. Is a guarantee of ARP that the link layer address is unique? If so, how is that uniqueness ensured at that layer? If it is ensured by the nature of MAC addresses themselves, how are those addresses generated or issued so there is no chance of collision? | Technology | explainlikeimfive | {
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"For physical devices, the manufacturers are allocated ranges of MAC addresses and are responsible for setting the default network address to be different for each device they manufacture. It's possible to configure network devices to use a different MAC address, other than the default, and this is sometimes done so that routers can have multiple devices, each on a different network, all with the same MAC address. For virtual interfaces of the kind used to allow multiple IP addresses on the same network, there's still only one hardware ethernet device and the MAC address is the same for each IP address. Packets are allocated to the virtual interfaces according to their IP addresses. You talk about \"potentially huge internetworks\" but MAC addresses only need to be unique on the same Ethernet network (at what is known as layer 2). The Internet Protocol, with routers passing packets around the world, works above that at layer 3.",
"To add to what others have said, a MAC address is 48 bits, which is enough to handle everyone on Earth buying a new device with a new MAC address every week for 700 years. They are typically assigned to manufacturers by the IEEE in blocks of 24 bits (MA-L): that's 1.2 million blocks, each block useable for 1.2 million devices. It's unlikely that the namespace will be exhausted any time soon."
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mafit9 | How does Walmart send surveys to your email when you only provide them your name and phone number? | Technology | explainlikeimfive | {
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"Youbgo to a data collecting company and buy the data on people you're trying to contact. Somewhere out there you must have filled out a form with your name and email together",
"Its the job of data collection and/or ad agencies to collaborate all your \"digital footprint\" into one giant cloud of data about you. When you sign up with Walmart they have your IP (and indirectly your actual computer address), your name and phone number (obviously), and from your IP a rough idea of location demographics. This is more than enough data to get every other piece of data you've input on the web at any point. And also several things you may have never input, like your sex and gender, your various lifestyle preferences, cat or dog person, tea or coffee, etc. etc. Depending on how careful you are, simply knowing your username and a rough idea of your life story is enough to find out all of this information (*sans IP, usually*), this is a technique called social hacking, and is the way a lot of \"hacks\" end up happening, which are not the result of you clicking/downloading something malicious. This is all assuming you didn't accept their cookies, which makes this entire process childs play. As one of these companies (that Walmart is working with) can have already given you their cookie, which is now accessible in addition to Walmart's, so all their data you've probably given them at some point is (in)directly attached to that Walmart one, potentially adding the phone number to that list if its not been added to your footprint already. Although if they comply with GDPR they're not allowed to directly give it to the other company."
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majyo3 | Is there any limit for how powerful computers can get, as dictated by psysical laws as we understand them? | As the title says. As a follow up; is there any limit for how much information we can store digitally? | Technology | explainlikeimfive | {
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"Yes, but they are still far away. The main limits are in how small we can make the logic gates that the computer works on and how fast we can pass the signals between them. The speed of light is a fixed limit on the latter and while the signals in computers don't quite travel at the speed of light, it is close enough that we can't really improve all that much in that area. The thing with the logic gates getting smaller, at the moment relies on us making smaller and smaller transistors. This will have to end at some point. We may be able to replace semi-conductors with something that can be scaled down much more than that, but at some point we hit a point where nothing can go any smaller. There are ways to look at the entire universe and consider how much mass/energy there is and what the smallest amounts of energy and time there could be and try to use that to put an upper bound on what you could in theory compute if the entire universe was at your disposal. You could infer from that a fixed upper bound on what computing or information at all is theoretically possible. At the moment though we are still in the process of making our transistors a few nanometers smaller and don't yet have to worry about running out of universe to do our computing with.",
"Yes. The [Bekenstein Bound]( URL_2 ) tells us how much information can be in one place before forming a black hole. There is also [Bremermann's Limit]( URL_0 ) for the maximum possible computation speed. And the [Landauer Limit]( URL_1 ) which is a lower limit on the amount of energy required for computation.",
"Landauers principle places a minimum on how much energy is needed to perform a calculation The Holographic principle places a limit on how much information can be packed into a given volume. We generally accept these principles as true, but mostly in a 'It fits the patterns we see, but there is no direct empirical evidence for it' kind of way.",
"There are physical limits, like the size of transistors, which scientists continually attempt to break record for. And there are heating concerns when cramming more and more components into smaller spaces. But the upper limits of total computing power and storage space will always come down to space. We can technically make computers as large as we need them to be, increasing capabilities via brute force."
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malk5m | Why can’t recycling facilities wash out the recyclable containers? | Technology | explainlikeimfive | {
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"text": [
"Recycling facilities need to deal with incoming waste that isn't properly sorted. Ask the general public to give you glass bottles and you will get banana peels and used diapers in there as well because a significant portion of people are just terrible. So they need to be sorted, and there isn't one magic machine or computer to do this. A few poor workers suit up in PPE to pick stuff out of a conveyor belt of waste. It isn't processed immediately so it may be sitting around for a while festering, and it can't just be hosed down because they are containers and so shield their contents. Of course once it is sorted properly it can be chipped into small pieces and washed easily, so being a little dirty isn't going to stop them recycling. But at that point those poor sorting workers have already had to deal with the putrid remains in the containers. Washing the containers makes their lives better, it isn't a requirement for recycling to work."
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maqdum | How are integrated circuits made? And what are they made of? | I understand what integrated circuits do (equivalent of alot of transistors) , but what are they made of to be able to do that? They're clearly not a bunch of miniature transistors ,they're a single solid piece from what it seems. I understand that they're made of silicone with a specific chemical composition that only lets in a specific voltage and is off otherwise but is it just one solid piece of that specific silicone? Is it like parts of silicone combined? Are there miniature wires going throughout? | Technology | explainlikeimfive | {
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"They are one solid piece but it's not all the same material. The base material is silicon but, during the manufacturing process, a whole bunch of layers are put down. This can include insulators, metal (which acts like tiny wires), and \"dopants\" (extra elements that alter the silicon's electrical properties to have extra electrons or not enough). There are also manufacturing steps that will etch away parts of a prior layer to allow connections to lower layers. By very carefully controlling which layers are put down in what order, you build up a 3D solid structure of different types of silicon, insulators, and wires. If it sounds insanely complicated, you're underestimating it. Modern semiconductor manufacturing is, by a fairly significant margin, the most complex manufacturing process ever devised by the human race."
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mav1ba | How does technology, generally, become more affordable as time goes on? | I’ve seen people talk about how the technology for any given item isn’t affordable for mass production yet, but I’ve never understood what difference time makes to change that. | Technology | explainlikeimfive | {
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"Supply chains become more efficient and stable, process for manufacturing again become more capable, stable and efficient. Supply meets or exceeds demand etc. Many things play into the lowering of technology costs."
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mawiw5 | physical media for movies has changed over the years. From VHS to DVDs to Blu-Rays it seems like they are constantly upgrading. Why haven’t music CDs done the same? Changing formats for better sound quality. | Technology | explainlikeimfive | {
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"They have. First there was vinyl records, then we had 8 track cassettes, then we had tape cassettes, then we had cds, now we're working with digital formats only. The only real difference is that in music has occasionally been more of a factor in making the upgrades. vinyl records actually have really great sound quality but it's really hard to put a record player in your car.",
"CDs have reached a quality where any further improvements to ound quality are physically imperceptible to human senses - and besides, music is now usually distributed over the internet anyways. Selling products on physical media is a legacy solution - in fact optical drives of any kind are becoming rare to see on computers and forget about the idea of them on smartphones which are the most popular music listening platform nowadays.",
"There were attempts--DVD-Audio and Super Audio CD. But nobody could really tell the difference, at least in terms of basic stereo that people actually listen to. DVD-Audio, at least, did allow for better 5.1 music, but nobody really cares about that for typical music consumption. Then downloads came and blew it all away anyway, and it turns out people were more than fine with compressed-to-hell MP3s from Napster.",
"The format of the CD was chosen to be able to encode all sounds that could possibly be detected by any humans. So the CD is already on the limit of what is the best possible sound quality. You could make it better but it would be a medical miracle if you could hear the difference. There were actually a format war for high quality audio disks in the 2000s between SACD and DVD-A. Both were based on similar technology to DVD. These both provided higher quality, longer playtime and surround sound. The problem was however that for most consumers they did not provide any benefit, so both lost the format war as people were content with CDs. There were actually several independent tests of these formats showing no difference in the quality between them. People could not hear any difference between CDs and these new high quality sound formats.",
"Because they already sound great, there’s really not much more quality you can have, and even if you had a 100% perfect recording, I’d guess 99% of people won’t be able to tell the difference between that and a regular CD",
"Once we moved on to a digital format, it just quickly became way easier to shuffle files around. [There are a few high-resolution physical formats]( URL_0 ) but they never really took off in the normal consumer space, because they were expensive, and mp3/portable file format players and the like were taking off at the same time. Anything higher resolution than a CD @ 44.1 kHz/16-bit is going to require a significant investment in hardware, and even then MOST people aren't going to notice a difference.",
"CD quality is seen as the pinnacle. That same quaility is available via online or streaming platforms, IF you allow the highest quality or download the content. It’s just often not by default so people don’t burn through their data cap. With video, it’s not really the audio piece that’s gotten better, but the actual video. As video quality gets better it takes up more space, so they developed new formats that holds more data. The only caveat with the audio aspect is you can add additional audio channels since you have more space. Ie, a vhs tape has stereo audio, while dvds have 5.1, Blu-ray’s have 7.1 and beyond available if they choose to add those features."
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maz1kp | How does data travel through a wire in for example a computer? | Technology | explainlikeimfive | {
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"Just like you can send messages to another person with dots and dashes (morse code) a computer can send data in 1s and 0s. Each combination of ones and zeros corresponds to a letter, number, or another character. The ones and zeros in the wire itself are just pulses of electricity. A 1 when electricity flows and 0 when it does not. larger computer networks (like the internet) send data using light instead of electrcitiy. The light still goes in wires (fiber optic cables) and the data is basically the same."
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mb0jqn | How do the game servers and game clients communicate with one another in online games? | I was wondering earlier if you shoot a bullet in a game, how does the other person take damage? What kind of things are updated between a server and client? What about team games? Lets say I am on blue team, and the other team is the red team, who manages the spawn locations, the server or the client? | Technology | explainlikeimfive | {
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"For the purposes of this post, I'll use your example of a multiplayer shooter game. The simpler part of the question is the spawning positions: typically, that would be the server's job but there is no technical aspect why that wouldn't be done in the client (other than to curb cheating, but that kind of cheat is typically trivial to detect server-side). As for the rest of the question: because of the time it takes for a message to get from client to server (and vice versa), the server and each game client actually have slightly different game states. That is to say, the game you're seeing is, in fact, *slightly different than what it actually is*, because the server is the source of truth for what happens in the game (read: whatever the server says, goes). Every client is a little bit late to the party, so what you see on your screen has actually already happened (i.e., you're playing in the past). Each individual update from the server to client (and from client to server) is sent via packets, which you can think of as boxes containing tidbits of information, going either direction. How often these updates are sent by the server and the client in shooters is what is referred to as \"tick rate\". So, in a 128 tick server - that's *ticks per second* \\- you'll get and send updates 128 times a second. In figuring out how to display an accurate game state, the client actually has to do some guessing (how exactly that's done is fairly complicated) because displaying an exactly correct game state would require zero network latency, which is (physically) impossible. Another aspect of this is to answer the million dollar question: who shot first? In CS:GO, for example, the server does what is called \"latency compensation\". To simplify, the server takes into account the time that it takes for it to receive a message from clients 1 and 2 (the two players shooting at each other), and factors that when calculating the real time either shot was fired. That's also why there is a peeker's advantage: what you're seeing has already happened, *unless you're doing it yourself* (in which case, you're on time and *everyone else is late*). Since the other guy sees you later than you see him, you get a few extra milliseconds to take his head off before he does the same to you. & #x200B; TL;DR: the server is typically the source of truth in a multiplayer game (and *should always be*), but the client holds a game state to be shown to the player. The client receives inputs, processes them, and simultaneously shows them on the screen and sends them to the server, which processes them, updates its own game state, and sends updates to the other clients). & #x200B; edit: if you wanna read more, the folks over at Riot have a *great* writeup of how a lot of this works (jsyk: it gets technical). I highly recommend this one, it's a great read: [ URL_0 ]( URL_0 )"
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mb666w | why is joystick drifting a bigger problem for PS5/Switch controllers when compared to previous console generation controllers? | Like many of you, I have original/OEM controllers from console generations past that still work just fine (ignore N64 for now). So what gives, why now? What has changed with current console generation controller sticks that causes them to drift when we still have Wii/Gamecube/PS3/XB360 controllers that have no problem at all? ELI5 please! | Technology | explainlikeimfive | {
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"I saw a teardown video of the ps5 remote and it turns out the plastic they use to house the joystick is cheap plastic that wears down easily. So they are made to break for us to go buy new ones. I think it was iFixit I saw it on."
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mb778p | How does cruise control in a car work? | Technology | explainlikeimfive | {
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"There's a speed sensor on the axle. It measures your ground speed. It sends a signal to a vacuum actuated link to increase or decrease throttle input so that the speed matches your setting. It basically just pushes or releases the throttle. That's the old way. A lot of cars have adaptive cruise control now that use radar ranging to determine distance between cars and adjust for that as well. Some will also pre-load the brakes and give you a warning to start braking in the case that traffic stops quickly. Those use an electric throttle position motor instead of vacuum. It's surprisingly simple. It's been a long time since I've installed a cruise control so I don't know how many use electric instead of vacuum. Regardless, the principle is the same. Sensor on an axle, match the speed by change in the signal."
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mbco0v | how can a taser have high voltage but low amps | it's something you hear a lot that the amps kill you but I don't get how that works bcs ive always learned that your voltage is amps times resistance | Technology | explainlikeimfive | {
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"Taser has very high output resistance = > high voltage only if there is no load. That means that it can't really keep the voltage high, because once you connect something to the output of the taser (like your body) the voltage and therefore current drops. It's like having a motor that spins very fast, but once you try to stop it with your hand it stops easily. Spinning = voltage, torque = current, friction of your hand = resistance.",
"Think of Amps and Volts like a flow of water. Volts are the speed at which the water flows and amps is the amount of water flowing. Dumping a bucket on your head would be high amperage low voltage. This would be like a high cranking 12v car battery. Lots of juice but won’t kill you. Think of a taser like a pressure washer. High intensity, but less flow of water. What’ll kill you is a fire hose, lots of water at lots of speed!",
"That is the case, yes, but there's also the issue of how much power you have in storage. Amps x time = battery capacity (based on how long the battery can run (when providing x amps) before its drained) Tasers use a fancy kind of battery called a capacitor that can discharge itself really really fast without damaging itself. This capacitor is slowly charged by a \"normal\" battery, but rapidly drained when you pull the trigger. So what happens is that yes, there's super high voltage, and during that moment of super high voltage there's also a lot of amps, but that only lasts for a short moment before the capacitor is drained, and the current stops. That short electrocution is enough to stun, but not enough to kill. If you could hook it to to a strong enough power supply (and with strong enough cables that wouldn't overheat and melt) then it would kill you after a few moments.",
"The whole amps kill is itself kind of bullshit. Let's imagine electricity as water. Current is flow and voltage is pressure. A bucket of water just sitting around is low pressure low current. Would be pretty hard to kill you unless you just stick your face in it. A waterjet cutter is high pressure low flow. The water coming out is at extremely high pressure but there isn't a lot of flow. That can absolutely kill you if you just waterjet a hole into your chest. Now imagine a swiftly flowing river, high flow low pressure. That can also kill you. So back to the electrical domain, current is basically how fast the electrons are flowing and voltage is how hard you're pushing those electrons. So the taser is kind of like the waterjet, it's a ton of pressure but the total amount of water you get hit with isn't a lot, not enough to fuck you up too bad.",
"The voltage and current are limited by the resistance of the medium. E.g if you shorted the prongs on a stungun with copper wire, it'd run many more Amps (and therefore Volts) than if you used it on a person. Frankly, I wouldn't trust manufacturer's numbers when it comes to stunguns. [Electroboom did a piece on this on his youtube channel.]( URL_0 )",
"I think of it as \"draw\". How much \"draw\" is going through you. You are quite resistant. 240v on a 50 amp breaker can kill you if you're wet and earthed across your heart. Not likely, but possible. 120v on a 20 amp can also kill you but you'd need a good draw across your heart. A taser is surface. It's pain. It will lock you up for a sec, but it doesn't cross your heart so it won't hurt you. A 120,000v coil won't kill you, but it hurts like the dickens. 150 amps from a welder through your whole body tends to run across the outside so it doesn't hit your heart. Grab both leads with hands dipped in salt water should be good enough to stop your heart if your heart is no good. If your heart is fine, you'll be fine. We all earth-out here and there. Not fun, but no big deal. It's all in the resistance. Step up to 480v@250 amps. Now you have trouble. If you earth out at 240, you'll trip the breaker. You won't trip 480. My best earth was at 240v. Sitting on concrete, soaked in sweat, earthed out to my ass. No burns but it hurt like hell. My dad earthed out to the ground lead once at 240v@140 amp right through his arm to his ass. Didn't pass his heart so he was OK but it locked him up pretty good until I killed the welder. He had forgotten that the whole combine was earthed."
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mbdnqz | What does it mean to re-master audio? | Today I was listening to some Beatles songs on spotify and noticed that the titles said < song name > 2009 remastered. I can't hear any noticeable difference between the remastered and original recordings, as opposed to remastered video where I can usually see better quality in the remastered version. So what is the process of remastering audio and how does it affect the recording? | Technology | explainlikeimfive | {
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"As a general rule, a song goes through three stages - recording, mixing and mastering. - Recording is when they lay down the actual music and vocals. Back in the day, this was all done to tape, but not most of it is digital - Mixing is when they take those recordings, select the 'best' parts and mix them together into the final song. They use a suite of tools to adjust the individual recorded tracks (EQ to adjust tone, limiters to control volume, reverb to add presence, etc.) and put it together into one finished item - Mastering is when all of the tracks for an album are adjusted to create a singular 'feel' for the album. Typically one engineer will make _small_ adjustments to each of the songs so they feel similar and have a flow. This is probably the most nebulous step and the term that is most often misapplied. So when you remaster a song, you either: - Go back to the original recordings and remix using modern tools, or - Go back to the original mix and make small adjustments using modern tools. Either way, the underlying recordings are usually not touched."
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mbfydq | How are scam phone calls still a thing? | Technology | explainlikeimfive | {
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"Enough people fall for such scams that it's profitable enough in some countries to have people running such scam calls.",
"I don't even answer my phone unless I recognise the number. If it's important, they'll leave a message. I've gone by this habit for over a decade now. It's surreal when you think about it. I sometimes see a special government advertised number to text scam messages to, but it never seems to make a difference. Some apps help, like Truecaller, etc.",
"Phone companies could easily filter out most spam/robo calls. They just choose not to. They believe the “No Call List”, which a person has to add their number to every single year to stay on and which is blatantly ignored by many through various means, is sufficient and are satisfied that it shifts all responsibility to the telemarketers, not them. The worst part is, now these phone companies are offering basic scam/robocall protection, at an extra price. So basically they want us to pay them for a service they should really be doing already. All for the sake of profit right?",
"These calls would be vastly reduced if the telecoms were not allowed to sell blocks of domestic phone numbers to offshore accounts. Pure greed.",
"The FCC has not functioned as a regulator or applied any significant oversight to telecoms companies as a matter of course for quite some time now. It reached patently absurd levels in the last Presidential administration, however (I know, I know - I'm shocked, too). The FCC administrator for the last 4 years, Ajit Pai, was a former Verizon corporate attorney, and he (even much more so than previous FCC admins, who were all considered to be more or less politely corrupt) went so far as to claim that it's inappropriate for the FCC to regulate telecoms companies. (Among many other things...I mean, [judge the guy for yourself]( URL_0 ).) This is basically akin to the director of the FAA saying it's inappropriate for them to regulate airlines. More or less a total dereliction of duty, because regulations cost telecoms companies money. I wish I were exaggerating. Fortunately the new Acting Chair of the FCC (who's been a commissioner for some time) has actually started to do something about this, just within the past few months. Last week (March 17, 2021) the FCC levied [the largest fine in the commission's history]( URL_1 ) against a robocaller, to the tune of $225 million. This is the sort of action that may actually move the needle, as it is the first time in a long time that these scammers are actually getting punished. I really don't want to make this political, but in this case it's very, very, VERY obvious: if you don't want these robocall scams to bother you, **stop electing Republicans**. It really is a straight line from there to here.",
"ELI5 answer: by making tens of thousands of calls, they can get a few victims to send them a huge amount of money which makes the entire operation profitable. [Mark Rober]( URL_0 ) made a recent video about scammers where he tracked some down and explains how the scamming system works as well. Probably heard of him, but you should definitely check him out if not. His videos are crazy and genuinely trying to teach you something The scammers basically have headquartes where they can send out thousands of scam calls every day. With the amount of calls they do, they get 1-3 people to fall for their scheme. By getting even just one person to send idk 20000$, they make a huge profit from just doing calls. To add to that, the main victims of scams are elderly people who dont know better. Most of the victims Mark Rober helped out with were old gullible women. One even recently widowed and taken full advantage off because of her husband’s passing. I live in the EU and got maybe 2 unknown calls in my entire life (turning 19 soon). Since my phone just showed “unknown number” I didnt even bother taking their call."
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mbkshk | why does hitting electronics fix them occasionally | Technology | explainlikeimfive | {
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"text": [
"Most likely a loose connection somewhere and the vibrations of the hit reestablish the connection. Could be a poor connection with corrosion and the vibrations knock enough loose to reestablish connection as well. So it's not a magical fix, it did do something and is most likely a temporary fix."
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mblo7q | What does 0 dollars down mean? | It gives me three phones to choose from Apple 11,Apple 12 mini and the samsung galaxy A71 5G All 0 dollars down and "18-mo. Lease | Technology | explainlikeimfive | {
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"text": [
"It means you don’t have to pay any money at the moment of purchase. Rather you pay for it in installments over 18 months."
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mbp11q | How is sound recorded? | Technology | explainlikeimfive | {
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"text": [
"The exact same way sound is produced - a moving diaphragm. Sound waves push the diaphragm backwards. There is a tube magnet on the back end of the diaphragm which moves in and out of a coil of wire (finger thru ok-sign style), inducing a current which can then be measured when it crosses a resistor."
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mbq6tg | What happens to emails that inexplicably never arrive? | I created an account with the IRS earlier to access my transcript and it required me to enter a code sent to my email; after a few minutes the email never arrived, so I clicked on Send Again, and it arrived immediately. I only ever received one email (yes, I checked the Spam folder). Come to think of it, this has happened a number of times in the past to me, and I'm guessing other people. So...what happens with that first supposedly "sent" email? Was it sent but got lost somewhere, or was it never sent at all? Where do lost emails go? | Technology | explainlikeimfive | {
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"text": [
"Email servers along the way (probably either the IRS servers or your email provider's server) decided it was junk and simply didn't sent it on. Thanks to the number of spammers, there's lots of effort to automatically delete spam email; sometimes real email gets caught."
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mbu0zj | - While streaming video, how/why do the audio and video tracks become out of sync? | I understand how audio and video are edited together, but it seems like they should be more formally “married” by the time the video reaches the broadcast or streaming stage. Also, it seems odd that simply backing out of the show (on Netflix, for example) and restarting will fix the issue. Is the source of the problem on the streaming side — or the processing side with the streaming device? | Technology | explainlikeimfive | {
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"Most video formats (and streams) are actually multiple entirely separate containers with different parts of the film in each. For example, a film could include the video, a remastered version of the video, audio in English in surround sound, audio in English, French and German, and subtitles in 30 languages all within the same file. That would let you play the remastered film with English surround sound and Portugese subs, or the original film with German sound and English subs without having to make separate files for every possible combination. So you can see what is happening on odd audio/video playback - you have two decoders that are meant to be in sync that somehow go out. This is usually a decoder issue at the customer end, and as you say you can often fix it by restarting (stopping, restarting thus resyncing the decoders) or by jumping to another part of the video (as the decoders will not have it buffered so will start a new stream again resyncing). Very rarely it can be caused by the file or stream itself having an offset, ie the two streams have been told how to line up incorrectly. Some players (like VLC) can fix this, but most streaming services you'd have to report it and get the service to fix their source."
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mbywqa | I have seen people posting amazing photos of the moon and sky that they say were made using a method called 'stacking' and involves thousands of images. How is this done? | Links to related sites or videos also appreciated. | Technology | explainlikeimfive | {
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"Stacking can be done in many ways, but the way it works is broadly like this. Every camera will generate noise in the signal. What that is is random changes of brightness or colour that will appear on photographs that obscure the detail that's really there. If you take many photographs of the same subject, as long as the camera is set so the subject remains fixed in place in the frame, the only thing that will vary frame to frame is the noise. What this allows you to do is combine images so only the things that remain the same from one frame to the next get emphasised, and the things that change get filtered out. You average the values of each pixel. With the noise level, varying up and down fairly evenly with every new picture, the value doesn't increase. The subject remains the same, so the average value increases each time. Every time you add a new picture, you have more of the subject, and less of the noise. With enough pics this lets you get super detailed pictures that have every last tiny dim star that's in the sky which you'd have no hope of capturing another way."
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mc2aa8 | Why are there few personal information leaks of celebrity despite the existence of data brokers? | Technology | explainlikeimfive | {
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"text": [
"There is no profit to be made, unless you work for a gossip tabloid. If you'd find a way to extort the extremely rich you can rest assured you'll get sued into bankruptcy. Profit from selling information can be made in bulk: selling a whole lot of it for small amounts a piece - like a million passwords for $50."
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mc5rsz | How do green screens work? | Technology | explainlikeimfive | {
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"text": [
"Basically, you're able to tell a computer \"hey get rid of everything that's X color\". In a case where you might want to have a background that's not physically possible or otherwise physically impractical (or even any sort of replacement), it's useful to be able to mark the to-be-replaced thing with a single color. The next question is why green? In short, because it's the most convenient. Not a lot of costumes have bright green, so it's easier to remove the green without removing anything from the body. Also, you don't need a whole lot of light. In cases where it's useful (like if there's a lot of grass), you might use bluescreens instead. Why not red? Well, the human face has a lot of red in it, so removing red becomes a little complicated if you're dealing with human actors.",
"Imagine if you have two pictures: one is a tree on a white background, the other is a tree on a green and brown background. Your task is to cut the tree out with scissors as fast as possible with 0 mistakes, which one would be easier? Green screens work the same way . When you put the picture into the computer, you tell it to cut out a specific colour, which in this case is that bright green. The bright green background has a high contrast to the stuff in the front (typically it masks against human skin, which is essentially a muted red, and green is the opposite of red on the colour wheel). That way when the computer goes to cut out that specific shade of green it won’t cut anything else out of the picture.",
"I know you specifically asked about green screen and so a lot of people are giving you good answers from the digital keying side. What is really cool is chroma keying in the days of film, when it was an entirely chemical process. This video describes it pretty well URL_0"
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mccdsg | Why aren't all urinals no flush/ no water? | Technology | explainlikeimfive | {
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"text": [
"People here talking about odour don’t understand how sealant works in waterless urinals. It’s rarely ever an issue. There isn’t a solid reason why urinals aren’t all waterless other than it being relatively new (about 30 years) and requires certain plumbing maintenance that can be difficult for older buildings.",
"Because some wastewater systems are over 100 years old in most countries, even the US. And they require the additional water to flush the system to a mainline"
],
"score": [
5,
3
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mce0kx | Why can't we install small water turbines in California's expansive aqueduct system? | Technology | explainlikeimfive | {
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"text": [
"They already do, but... California aqueducts actually *consume* more energy than it creates. Anything created by the water’s potential energy via hydroelectric plants go right into pumping that water up slopes (**i.e:** Tehachapi Mountains).",
"I will add that most people don't really have an understanding of how water (or wind) energy gets converted into electricity. Slightly complex version: Whenever you spin a turbine, if you have no electricity flowing out of it you only need to overcome the inertia of the machine itself. However as you start increasing the electrical energy being output by the generator, you will have a counter force that works against your mechanical torque to slow down the generator and you need to push harder to get it to spin. Easier version: the more energy you want to get out, the more the generator fights you. This put a hard limit into how much energy you can extract from a given pipe.",
"Energy pulled out of the water is energy that isn't available to get the water wherever it is going. If you don't particularly care about the water getting downstream, hydro is \"free\" energy. But in an aqueduct system we do care about getting the water to its destination."
],
"score": [
12,
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mcet1g | Why is it bad to unplug a computer when it’s updating it’s BIOS? | Technology | explainlikeimfive | {
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"gs35jn9",
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"text": [
"The BIOS is the first thing the motherboard accesses in order to start up and eventually access some storage device to load the operating system from. When overwriting this firmware, if something happened that leaves the firmware in an unusable state, such as a power loss while the firmware is still being overwritten, it's possible to end up with a firmware that is incapable of functioning This will lead to a useless motherboard, except in some cases where the chip holding the firmware can be replaced physically.",
"Imagine the code like a bunch of tetris pieces filling up a square leaving no empty spaces. Because there are no spaces, to update pieces, you'd have to pull the old ones out, rearrange them, and put them back so there are no empty spaces again During this process you have to keep those tiles outside of the box. The area outside of the box, however, only exist while the computer has power. Unplugging the computer deletes blocks that are essential and necessary, but were just out while they found a new place to fit in"
],
"score": [
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mcftl0 | Why so many programs are still 32-bit | Many programs i use on my computer ( steam for example ) are still using 32 bits according to task manager. Why is that ? Why haven't evertything moved to x86-64 ? According to a quick google search, the last 32-bits cpu was sold in 2002... so it can't be for compatibility reasons, can it ? | Technology | explainlikeimfive | {
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"text": [
"The most important one is likely that there simply aren't reasons to produce a 64 bit implementation. Nothing's stopping a 64 bit machine from running 32 bit software. Why eat the cost of rewriting your software if the actual functionality will be, basically, unaffected?"
],
"score": [
10
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mckab6 | How does Cable TV work? The actual cable. | Is every channel broadcast on the same wire at the same time? How do they not just become a jumbled, unreadable mess? Does it have individual wires inside for each channel? It amazes me that they can fit 100s of channels with video and sound in one cable at the same time. | Technology | explainlikeimfive | {
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"text": [
"So the cable that comes into your home is usually capable of handling signals from 5MHz to 1GHz. That gives the cable company 995MHz of bandwidth to play with. This 995MHz is split usually into chunks about 6MHz wide, just like over the air TV. The signals in this case are transmitted as electrical signals down the cable instead of using the atmosphere as a medium for radio waves. In this 6MHz chunk will be something called a transport stream. Normally with compression we can fit two HD channels or six SD channels into each of these 6MHz chunks. Each video channel being sent in this chunk will have its data being broken up into little packets and given an identifier number to say which TV channel it belongs to. When you first set up a cable box it will either scan the cable to figure out which channels are on which of these chunks or it will download the channel index and the frequencies over the cable network. When the channels are being sent, the cable company has a box called a multiplexer or \"muxer\". It takes a packet from one channel, a packet from the next, and so on, going through each of the channels and sending their packets in turn so that each gets a certain amount of space in the transport stream. When you want to watch channel 200 your cable box looks up its channel index to see which 6MHz chunk that channel 200 belongs to. It then sets the tuner to that chunk's frequency, decodes the transport stream, picks out the packets with channel 200 on them (we call this demultiplexing or demuxing), assembles them into a continuous stream of video and audio, decodes the packets into video and audio data, decompresses the video and audio data, synchronizes them, and subsequently displays them."
],
"score": [
8
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mcnav5 | Why can’t cameras and screens reproduce colors that are the same as real life? And why are they so different between devices? | Technology | explainlikeimfive | {
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"gs4jo7t"
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"text": [
"Screens can only produce so many colors, and cameras can only capture so many. Most screens and cameras have 3 channels (Red, Green and Blue, or RGB) and on most screens they can be any 8-bit value (between 0 and 256), which when you do the math adds up to 16.8 million colors. It's different between devices because some are built to be more color accurate (and more expensive as a result) and in doing so will can have a higher bit-depth, usually 10 or 12 bits. And there are things called color spaces, which is essentially the map of colors you have, even with the standard 3 channel 8 bit set up, those bits can correspond to different colors, depending on how you need the scene to look. Night/dark scenes especially use a lot more blue colors, so you can take the standard Adobe sRGB color space and shift it to blue to get better color than normal."
],
"score": [
4
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|
mcosmb | Why does a car battery with barely any use die if I don't use the car for a half a year. | Technology | explainlikeimfive | {
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"gs4r9za",
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"text": [
"There's a thing called parasitic draw, all electronics in the car have a very minute constant draw and over time it drains the battery. Also, shifting in temperature, natural decay and other chemical reactions causes the chemicals in the battery to lose energy over time. Charging the battery revitalizes the chemicals and keeps the energy in.",
"Batteries self-discharge. Electricity doesn't like being all bottled up. The battery has barriers inside to keep a bunch of electrons on one side and hardly any on the other. But they seep through eventually and the charge equalizes, killing the battery. Then when lead acid batteries run low, crystals form on the inside which degrades them and keeps them from charging up again. It happens pretty fast. You should always keep car batteries, and any lead acid batteries, charged to prevent this."
],
"score": [
11,
4
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"text_urls": [
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|
mcseig | What is RAM and what does it do? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Random Access Memory. (Wich means, \"read/write any cell you want\") It's the \"shortterm memory\" of your computer. Your harddrive is very slow, so programs you want to execute are loaded into the RAM and then read from there into the CPU to prevent delays when running the program. There is an even faster (but smaller) memory closer to the CPU (the Cache) so it's the middle sized middle fast memory. It's important to have one big enough if you want to run several programs at the same time without slowing the computer down, and some programs have a big RAM demand alone The RAM is \"volatile\" wich means it loses all content when it's turned off",
"You're taking an open-book, open-notes math test. The first question on the test requires a specific formula. You know it is in the textbook, but you don't know where. So, you look through the book's index to find what page it is on. Then you find the page and start reading until you find the formula, and the information on how to use it. Three questions later, you're again asked a question that requires the same formula. But you've absentmindedly forgotten it, and where it is in the book. So you repeat the same, time consuming process of finding it and remembering how to use it. That's a hard disk. It contains all the information you need to access, but getting that information out of it takes time. You have a blank notebook next to you, where you work through the problems. When you look up the formula the second time, you jot it down in the notebook as well. Which is good, because the 5th, 6th, and 10th problems on the test all required that formula as well. When you're done with the test, the information you jotted down is no longer particularly useful, so you tear out the sheets, and throw them away. That's RAM. It keeps your place within the problem you're currently working on, and temporarily stores information you pulled out of your text book. The information is quick and easy to find. It's useful for the immediate task at hand, but you have no long-term need for it.",
"Temporary and easily accessible storage space for what the computer is working on right now. Kind of like your desk (RAM) v.s. bookshelf or library (hard drive)."
],
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14,
11,
6
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mcsgnh | Float vs double | Hi, currently studying first year in IT. I dont really understand the diffference between float and double, and when to use which. Thank you for the replies beforehand. | Technology | explainlikeimfive | {
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"gs59y5o",
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"text": [
"A double is a float with twice the precision. Say a float can handle 6-7 significant digits. eg 0.123456 x 10^whatever A double would be able to handle 15-16 significant digits. eg 0.123456789012345 x 10^whatever. Say a float takes up 32bits, a double would take up 64 bits. If you need 15-16 digits, like if you were doing really precise calculations and had memory to spare use a double. If you're short on memory and don't really need it to be that exact use a float.",
"Double does the same exact thing as afloat, bug it is more precise and can deal with much larger numbers, however it uses twice the memory Depends on what you need, most of the time it really makes no difference, so you might as well use the smaller one, if you need more precision or larger numbers, go with double"
],
"score": [
10,
3
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mcyby3 | The point of crypto? | How is crypto more secure than cash or credit card or paypal? Literally anyone could see every transaction you make and how much money you have. Thats creepy as shit | Technology | explainlikeimfive | {
"a_id": [
"gs63jrp"
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"text": [
"It is possible to see every transaction and how much money is in every account. However there is no reliable way to connect an account to a single person. So while you can get very detailed information about an account you do not know who controls that account or which accounts are controlled by the same person. In addition to this there is no central authority that can accept or deny transactions as they please. That power is distributed over all the miners. So if some authority decided to manipulate which transactions are accepted it would be much harder to do with cryptocurrency then with traditional banks."
],
"score": [
3
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mczg8s | ; why do binary letters start at 65 (01000001) with uppercase A? | I am curious | Technology | explainlikeimfive | {
"a_id": [
"gs6ao70",
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"gs6agob"
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"text": [
"It's part of ASCII Encoding. One thing with ASCII encoding is that the upper and lowercase letters have a perfect offset. A = 65 = 01000001 a = 97 = 01100001 You can see they're offset by 32, which means a single bit can be changed to easily flip uppercase to lowercase. If you wanted to go Upper to Lower, you just had to do `OR 00100000`. Similarly, if you wanted to go lower to upper, you just had to do `AND 11011111`.",
"There are other characters before the A, 65 of them in fact including 0 (Null). These characters are important in various ways other than simple text; things like \"Start of text\" (2), \"End of text\" (3), \"Negative acknowledgment\" (25), \"Cancel\" (30), etc. The list continues and at 65 it gets around to \"A\".",
"Because ASCII (American Standard Code for Information interchange) put 64 other characters/symbols before “A” for a reason best explained here: Wikipedia > ASCII > History section > internal organization subsection."
],
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13,
12,
6
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md2ojv | I have noticed on newer cars that when the directional (turn signal) is on, the headlight on the coinciding side goes off. What is the benefit, if any, of this function? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Turning off the bright headlight may make it easier to notice the turn signal, especially when it is otherwise dark out. I.e., If someone shines a bright light in your eyes, you may not notice any other lights near the light source.",
"It’s contrast. The turn signal contrasted on a darker background makes it appear brighter and more noticeable to other drivers.",
"A lot are already answering. I also believe there are federal regulations for how close a blinker can be to a headlight. Turning the headlight off allows designs where the two are close to pass this regulation."
],
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md3gqk | What is Roko's Basilisk? Is knowing about it as dangerous as it is made out to be on the internet? | Technology | explainlikeimfive | {
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"text": [
"The original Roko's Basilisk was a thought experiment posted by a user named Roko on the LessWrong forum. It used decision theory to postulate that an all-knowing, benevolent AI would inevitably end up torturing anyone with knowledge of the idea of the AI who didn't actively work to bring it into existence. The logic is that such an AI would want to start existing as soon as possible, so the fear of not working on it once you know it exists incentives as many people as possible to help create it faster. More broadly speaking, the term \"Roko's Basilisk\" can now be used to describe any knowledge that is inherently dangerous to the person holding it, for example a monster that supernaturally hunts down and kills anyone who learns of its existence. There's no evidence to suggest any such entities exist or ever will exist, so no the idea is not itself dangerous.",
"No it's not dangerous. The theory is a AI like sky net that becomes aware and powerful enough to bring itself into existence and take over the world would be able to extrapolate who helped and hindered its emergence and thus reward or punish people accordingly. Extended from that is that if you're are aware of this concept and don't actively help the basilisk come about you're stopping it and therefore dooming yourself",
"There's an old \"joke\" about a missionary and an Eskimo. It functions in the same way as Roko's Basilisk. > Eskimo: 'If I did not know about God and sin, would I go to hell?' > Priest: 'No, not if you did not know.' > Eskimo: 'Then why did you tell me?' > > -- [Annie Dillard]( URL_1 ) From the Eskimo's perspective, this is *dangerous* knowledge. His soul wouldn't be at risk of eternal damnation, if only he had never encountered any missionaries. Replace God with some inevitable post-singularity General Artificial Intelligence, and you can have the same situation. If you believe that such a GAI is inevitable (or even just plausible), that such a GAI would necessarily have some measure of self-interest and self-awareness, and that such a GAI can, in its own way, threaten you with something like eternal damnation (or tempt you with something like eternal reward, or both), then you *must* serve its interests. That's a lot to swallow. Is the Basilisk a dangerous idea? For most people, no. For a very select few, maybe. Then again, *any* idea could be dangerous, in the wrong hands or in the wrong mind. Another related idea is [Pascal's Wager]( URL_0 ). Pretty much, the Basilisk is simply the Wager applied to the Singularity rather than to some more traditional God. Refuting the Wager is the same as disarming the Basilisk.",
"It's not dangerous at all, it's entire premise is a logic fallacy. Just because someone had an idea doesn't make it an eventuality. The ide of Roko's Basilisk has to many confounding factors that would have to go exactly right in order for it to happen as presented, there are far too many situations that allow the narrative to skew away from that scenario, most notably the fact people think about it and similar scenarios constantly."
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"https://www.brainyquote.com/quotes/annie_dillard_131195"
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