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k7or2j | how exactly do apps like instagram and snapchat know when we take a screenshot? | Technology | explainlikeimfive | {
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"Because you allow them to track all activities on your phone unless you go in and specifically block the tracking, which most people don't.",
"Each action done on an app is recorded. They are stored. Some apps simply discards or ignores data like screenshot and other stuff. As for Instagram and snapchat, they leverage on this data and uses it to catch screenshots."
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k7pa5u | how does winrar gets profit if it don't even force the user to buy it. | Technology | explainlikeimfive | {
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"Winrar is fully aware that the advrage user does not pay for their services. And they dont mind at all. Winrars profits come from companies and businesses who use their software. This is because a commercial buisness CANNOT legally use programs without purchasing lisence to do so for every single computer used. TLDR: Companies pay for winrar, not casual people."
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k7ucnm | Where do new crypto exchanges get their liquidity from? | Bitcoin needs to be mined and isn't owned by anyone. Now, if I'm starting an exchange, where do I source the coins from? What's the process like? And how is risk managed. Any information is highly appreciated as I'm trying to learn more about crypto. | Technology | explainlikeimfive | {
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"You'd have to buy it from another exchange or build relations with miners to buy direct, or heck, and I'm just guessing here, if relations were built, you could sell another exchanges coins on thier behalf through your exchange."
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k7v84x | How does data compression work? How can a .zip file weigh a ton less than the original file? | Technology | explainlikeimfive | {
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"You find a pattern that is frequently repeated throughout the entire data, and write it down once and replace it with a reference. You do this over and over again, replacing everything that is sufficiently long and sufficiently repeated with just a reference to a dictionary where all these terms are written once. It's like if I took the pattern *2444666668888888\" and wrote it instead as 12345678. The application decoding it knows to read it as 1 2, 3 4's, 5 6's, 7 8's. I shortened 16 characters to 8.",
"I think it helps to think about file size more like *space* instead of *weight*, then the concept of \"compression\" is more like changing the density of an object (packing more stuff in the same amount of space) Sometimes we can break things apart to make them fit in a smaller space. Take an Ikea wardrobe, for example, that fits in two heavy flat-packed boxes. All the components are still in the box, but they need to be assembled. Once assembled, that wardrobe is now much bigger than the boxes it came in. A program that creates a `.zip` file knows how to disassemble the files to make them take up less space. Similarly, it knows how to reassemble those parts to rebuild the original. This is also why other compression schemes exist–`.tar.gz` does similar things but uses a different set of rules for disassembly and reassembly",
"Here is how: 1 000 000 000 000 000 000 000 000 000 versus 10\\^27 In short, \"\\^27\" means \"27 times zero\", which is a shorter way to write down a number. If there is a pattern in data, it can be better to write it down as the pattern itself.",
"You could also think of it as instead of using a product, you save the blueprint of how to build the product. So while a cupboard takes up a lot of space if you would take it's components one by one and play a little Tetris you could fit them into much less space. And as the components are basically just data, you could simply create them when you need them."
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k7xm8c | how zipping a file actually works? Cause it’s the same amount of data just not | Technology | explainlikeimfive | {
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"1, especially written text 2 3 redundant, 4 2, it contains a lot of 5s of 6 same things. 6 way compression works 2 by searching for those 5ing parts and building a dictionary 4 assigns a shorthand symbol for each 5ing 1 segment. 6 specifics vary, 6re are a lot of different algorithms for compression. Some favor size, some being 3 fast, and some are general and kind of a middle road. ---- 1 data 2 is 3 very 4 that 5 repeat 6 the",
"Lossless compression (as with .zip-files) finds patterns within the data that can be expressed in a less space-intensive way, e.g. \"compressing\" the string *AAAAAAAA* to *8A*. Lossy compression *removes* part of the data that is deemed unnecessary for human consumption (e.g. removing frequency ranges that can't usually be heard by humans from an audio track).",
"Imagine you're reading a book. The word 'the' appears in the book 2500 times. Replace all the instances of that word with a placeholder like '@' Then put an index at the from of the book that says '@' = 'the' By doing this you save on printing 5000 characters (2500 words * 2 letters) If you repeat this for a lot of other common words you save a lot of space, but the book contains the exact same information. This is the basics of file compression."
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k7zkvc | Why are mobile screens above 330ppi are very cheap but monitors and TV panels are not? | Technology | explainlikeimfive | {
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"I assume it has to do with the size of the panel. At the same pixel density a large panel has 10s of times the number of pixels and this requires more materials, larger equipment, and probably more difficult quality control.",
"There's little need for monitors and TVs to have such high resolution/PPI. You typically hold a phone maybe a foot from your face, computer monitors are a little further away on average (they would probably average closer to 2-3ft with some people having them a little closer or further). TVs are generally even further likely at 6ft+ from your face. The smaller/closer together pixels are, the *closer* they can be to your face before you notice a difference in quality (or see individual pixels). There are limits to the level of detail your eyes can make out, but something like 1080p will look the exact same at something like 8 feet away as 4k on a 40\" TV. But bring that 1080p inches away from your face? You need higher resolution to avoid seeing pixels. You can find calculators online that will give you the exact distances/optimal resolutions, and it's based on what the eye is capable of seeing (on average)."
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k80n6u | Apple M1 Neural Engine and what differentiate it from Intel i cores? | Technology | explainlikeimfive | {
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"There are quite a few differences between the M1 chips and Intel processors. Firstly, the M1s are actually something call a System on Chip (SoC), meaning that it's a single unit that contains lots of different parts. The M1 contains a CPU (the processor), a GPU (a processor specifically for graphics), RAM (the memory the system can access), and the neural engine (another processor that is designed for running artificial intelligence programs). On the other hand, Intel processors only have a CPU (and sometimes a GPU), the other components are separate. Now if we focus on just the CPU there are a lot of other differences. CPUs are given a series of instructions to understand what they need to do. Intel (as well as AMD) use a system of instructions called x86. This is basically a very long list of instructions, meaning that they can do a really complicated operation with a single instruction. This makes them great for a lot of high performance applications. However, having lots of special instructions means that there is a lot of extra hardware inside the chip for understanding and acting on these instructions, this causes them to be less power efficient. The M1 uses an alternate standard called RISC (Reduced Instruction Set Computer). This is a design that has most famously been used by ARM, the company that designs the processors you'll find in the majority of phones. In fact, the M1 chips are actually heavily modified ARM designs. RISC uses a much smaller amount of simpler instructions, and combines them together to perform more complex operations. The advantage is that the chips are more power efficient compared to x86 designs. Traditionally this meant that you'd want an x86 CPU in applications that need high performance, and RISC in ones that needed good battery life. However some other advances we've made in CPU design means that we can actually get really great performance from RISC without sacrificing the power efficiency. x86 is still the most powerful option overall in terms of the raw amount of operations it can do, but for most users this isn't something we need. Companies like Microsoft and Apple have realised this, and so have started to push to use ARM/RISC CPUs rather than x86 for portable devices like laptops."
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k828uh | Why does Google Earth edit-out northern polar ice cap? | In Google Earth and Google Maps (and many similar services on web) you are not able to see north pole's ice cap. why is that? | Technology | explainlikeimfive | {
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"The North Pole has no land mass. It's just ice, as opposed to the South Pole. Which is it's own continent.",
"Google maps exclude both poles because the projection they use would put them an infinity long distance away from the equator. So the cut of the maps at 80 degrees because that includes almost all that would be used on maps. If you look on google earth you will notice quite to all coast the water change from airplane and satellite images to a rendered blur area where the color depending on the water depth. The change is approximately 1 km from the land where I measured it. So Google Earth does not threaten the north pole in a special way but renders the seafloor like in all other oceans."
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k82h1h | Cyberpunk 2077 started production in 2012. Since then the ps4 and ps5 had launched. Did they program the game for the ps5 before the ps4 was even launched? | Technology | explainlikeimfive | {
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"No. Cyberpunk wasn’t really in development that long. CD Projekt Red just revealed it and then went back to work on The Witcher 3. Then in 2016 when development on W3’s final expansion Blood & Wine was almost complete they moved a small group of employees over to begin development on Cyberpunk. Once B & W was completed the rest of the team joined the small group on Cyberpunk and that’s when full development began."
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k83ezb | What is a “super computer” and what can it do? | Technology | explainlikeimfive | {
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"Thus far no ELI5.... Humans did math with pen and paper or whatever until calculators were created. Which does basic math for us quickly. A computer is basically a calculator created to do MORE math faster. A regular calculator can do 1 \"math\" at a time. A 5ghz CPU in a desktop computer can do ~5 billion of \"Maths\" per second. So a super computer is basically a bunch of regular computers working together. So if a super computer has the equivalent 1,000 of Desktop computers working together it 1,000*5billion = 5 trillion \"Maths\" per second. Being able to do the same math as 5 trillion calculators in 1 second allow us to analyze incredibly large amounts of data faster. Data analysis is the core of prediction of things. Such as weather. TLDR: A bunch of computers connected to each other can do Math faster than 1 computer alone.",
"A super computer is just a big powerful computer. In the 60-70's super computers were single powerful computers like the famous CRAY-2. The appearance of the CRAY-2 is quite distinctive and is still used as the symbol to represent super computers to this day. This was the era of mainframe computers where a single computer was shared between everyone in a building using terminals. The idea of individual PCs on everyone's desk hadn't been figured out yet. While today what we call a super computer is in fact a cluster of 100's of regular servers working together as a single machine. If you walked into a server room with a super computer in it you probably wouldn't recognize it as such, it just looks like any other server room full of identical rack mounted servers. Such a computer uses distributed processing, meaning that a task is broken up into smaller pieces by a command and control server and distributed to individual 'nodes'. This way a super computer can spread out the workload of a large mathematical problem across the nodes and perform the work much much faster than on an individual machine. Super computers are used to process very large mathematical models like calculating the trajectory of millions of theoretical stars around a galaxy of the period of millions of years. Running such models while tweaking the variables gives us ~~incite~~ insight into the nature of things like gravity. At a fundamental level though the individual nodes are just powerful servers with the same types of CPUs and memory as your PC. So they could theoretically do anything your PC at home does, just a lot faster.",
"Supercomputers are special-purpose computers that link together higher-end components from typical computers using specialized hardware to achieve state-of-the-art processing power. Many supercomputers use hundreds of thousands of individual processors working together to coordinate and solve some problem. But that alone does not make a supercomputer--for example, Google's MapReduce uses large amounts of commodity-class machines to perform distributed and parallel computation. Supercomputers also generally have extremely fast memory, so the thousands of processors can work together on the same problem while sharing (mostly) the same memory. This is facilitated by extremely fast networking hardware called the \"interlink:\" high-end supercomputers make it so that talking to another machine is almost as fast (or at least much closer to the speed) of local RAM. In practice, different supercomputers are organized in different ways to optimize for different kinds of workloads they handle. You can read more on wikipedia: [ URL_0 ]( URL_1 )",
"Super computers are purpose built to perform computing tasks at a higher level of performance than a commodity, retail, or workstation computer. Your phone today is several orders of magnitude more powerful than the first super computers, such as the famous Cray-1, but that doesn't, in some way, demote a super computer. Typically, super computers use processors that are designed for math operations, very much like a video card's GPU. There is an encoding into binary bits of \"real\" numbers called a \"floating point\", and these computers perform many FLoating point arithmetic calculations. The number of **FL**oating point **OP**erations a computer can perform per second is called a **FLOP**. There are, or were, general purpose super computers that weren't especially focused on floating point operations, and they measured the number of CPU instructions they could perform per second, not just floating point instructions, and they measure their performance in **M**illions of **I**nstructions **P**er **S**econd, or MIPS. What they can do is kind of hard to say beyond the above, without also talking about what they're used for. Today, most super computers are used for physics simulations. These simulations are most often for weather, but also for nuclear physics, astrophysics, material sciences, chemistry, and engineering. There is a long history of super computing. The earliest machines were analogous to superscalar single core machines, compared to their contemporaries. These early super computers pushed the computational boundaries of their days regarding materials, signaling, and propagation among the circuitry of the day. Cray-1 is regarded as one of if not THE first super computer, and while integrated circuits were invented by this time, they were so new, Seymour Cray basically didn't trust them? He built his first machine using discreet components. Eventually, miniaturization smacked face first into the physical limits of quantum physics, so smaller and faster was no longer a way to chase down performance. We call this vertical scaling. So the machines stopped scaling vertically, and instead went horizontally. More cores, more nodes. If you saw a super computer today, they would be racks and racks of nodes in a data center. These are not individual computers in a closed network! These nodes cannot \"boot\" and operate on their own, they don't each run their own operating system, they don't each have their own video port, or their own disk drives. These nodes are little more than CPUs, and do not operate in a standalone fashion. The network that combines the nodes aren't your typical Ethernet network, either. The sum of these nodes and the network that interconnects them constitute a single computer with hundreds of thousands of cores. Your computer has many compute cores within it - if you just look at task manager. These computers have many cores within each CPU, and many CPUs, not just within a single node but spread out among hundreds and thousands of nodes. Then there are compute clusters. These are a distinct class of computing. They're not super computers, though they will get called that often enough. These are indeed individual computers, each one can run standalone, each one made from off the shelf parts. They're just arranged with a private network and special software to sort of treat each node in the compute cluster as a worker node. Work is farmed out in batches to nodes that need work. You can assemble one of these in your own home, and they're popular among businesses and universities on a budget. A classic cluster computer setup would be a Beowulf cluster, though not relevant in the modern era. There are grid computers. This is similar to, but distinct from a cluster in that each unit in the grid can do different work, whereas a cluster is focused uniformly on a singular goal. Then there is distributed computing. This is where computers all across the internet can download a client that helps manage the work to be done. SETI@Home and Folding@Home were and are popular, where that since your computer spends most of its time idling, it uses that idle time to perform work. And then there are mainframe computers. These are not super computers, and the term does not mean some really old computer of a bygone era. In fact, the business behind mainframe computers are alive and very well, won't go away any time soon, and is even expanding. Mainframe computers do things that none of these other computers can do, and that is they perform transactional computation - an all or nothing sort of thing; either the computation is complete, verified, and committed, or not at all. This is *exactly* the sort of computation you want when handling financial transactions, like when you pay with a credit card or transfer money. The other aspect of a mainframe that unique is the high throughput, which is a very specific metric. Just one of these mainframe computers can perform billions and billions of transactional computations in a single day, non-stop, uninterrupted, for years or decades at a time. I once got a tour of one of these machines, which takes up several racks in a data warehouse, and the largest ones made today have a couple thousand processors and modules just dedicated to moving and managing data to keep the CPU fully saturated with work. Nearly the entire financial system worldwide is built upon these things, as are many government systems. When COVID hit and the US unemployment office got completely slammed, remember when New York Governor Cuomo blamed the decades old mainframes? Nope, those babies were humming along just fine, underwhelmed. It was the more conventional web frontends that absolutely crumbled under the load. But mainframes are not super computers, they are only good for the type of work that they do and are thus very special purpose. There is cloud computing, which is what my company does, and that is basically paying someone else to manage the hardware, and the client rents use of computer resources. Lots of companies choose cloud platform providers because owning and maintaining hardware can be expensive. Some providers have performance oriented offerings. Finally, there's High Performance Computing. This is like a mini-super computer. You see the Bitcoin miners do stuff like this all the time, where they'll either stuff a computer with as many video cards as possible for their math processors, or they'll use custom FPGAs or ASICs (basically, purpose built custom processors).",
"A super computer is a cluster of regular computers all working together on problems that are too big for just one computer to handle. The really tricky part is figuring out how to break the problem up so that all of the individual computers can be working on the same problem at the same time.",
"I work on a supercomputer on a daily basis. I'm going to talk about that supercomputer, Cedar, to help you understand. A \"node\" is equivalent to a single computer, but they're higher-end then a normal computer. They'll have two processors, blazing fast memory, and many forms of storage that are all faster than what you probably have in your computer. Still, nothing mind-blowing, but hang on... Cedar has two head nodes and one scheduler node, along with 2470 actual nodes for actual computing. When I log into Cedar, everything I do is done on a head node. But when I want to run a program, I enter in the following command: sbatch URL_0 which tells the scheduler to add my task to the queue. When it's my turn, the scheduler will do whatever's in URL_0 . An example of what I might put in that file would be: #!/bin/bash . ./env_vars.sh mpirun -np 40 ./wrf.exe which would tell the supercomputer to launch wrf.exe (a weather forecasting program) with 40 processes/threads (which would all be on one node). WRF would, in turn, divvy up my weather forecast for, say, an entire state, into a 5*8 grid and assign one grid for each CPU thread. So far, so good. Nothing I can't do at home. But wait -- what if I need to forecast the entire globe? Or run another program that requires resources far beyond what one node has? That's where supercomputers really shine. What makes Cedar a supercomputer, in my opinion, is the connection between the nodes. If you had a thousand computers at home, that wouldn't be a supercomputer because they wouldn't be linked efficiently. You couldn't run a program that uses all of the resources in any efficient way, because the only way the program could communicate between the computers would be through 500500 ethernet cables between them, or an overloaded router, which is going to slow your program the fuck down. Because, you see, the weather in one grid square affects the weather in the adjacent grid square, so WRF needs to pass massive amounts of information between the computers. Your dinky little setup won't be able to handle it. Cedar, on the other hand, has an amazing interconnect that can communicate between nodes with barely any loss in speed, with 100 Gb/s in bandwidth. (Intel OmniPath, if you're curious and want to google it.) The upshot is that I can submit a program using thousands of nodes (over 100,000 threads/processes), using hundreds of terabytes of memory. So in my URL_0 , I could ask wrf to divvy up my forecast into 10,000 pieces, say, to forecast the entire globe: mpirun -np 10000 ./wrf.exe To answer your question, then, in my opinion, scalability is what makes a supercomputer: being able to run the truly massive tasks requiring many nodes.",
"A \"supercomputer\" isn't anything specific, it's more a marketing term than anything else. The top 10 or so fastest computers at any given moment get to be called supercomputers. A modern iPhone is much more powerful than some of the early supercomputers.",
"I like the top comment but I thought maybe I'd try another, quite relatable take: Think of something like a county's election. The most recent US one is still fresh for most people. You had around 155 million votes in that election. Those all need to be counted. If you have one guy name Steve who has to count them all one at a time, it's going to take a looooong time. So you hire 2 people. Or 3 people. Or 50 people. Or a million people. Then you spread them around so that the votes are counted closer to their origin. Then you upgrade to machine counting, etc. In the end you have one overall \"tally\" with *lots* of different pieces involved in the counting and done *much* faster than if it was just that one guy counting. A super computer is similar in that it takes one *very* large and *very* complex task and completes it much faster than a single, simpler computer could. Your home PC is Steve. The super computer is the entire system of people counting. In the end Steve could maybe count a few thousand votes on election night. But the entire system working together can give a pretty damn good picture of who won an election *on election night*. Much faster.",
"I work with super computers on some projects for work. In many types of science, engineering, and even movies, there are lots of tasks that require individual processing. Let's say you are making a movie, and on each frame you are trying to simulate a fire, the scene lasts 30 seconds, and there are 24 frames per second. For each of the 720 frames, the computer has to do the math to make the flame graphics look realistic, and then overlay the fire on the original picture. The more realistic the flames, the longer it will take to calculate for each frame. You could do this on your computer at home, and process each frame in sequence. This would take a very long time, especially because fire simulations require a lot of math and physics to make look good. The main feature of a super computer is that it has a lot of processors. You can think of a processor as a person who is doing a job. Your home computer could have anywhere from 1-16 workers, depending on what kind of computer you have. Let's say your fire special effects take 1 minute to calculate per \"job\". If you do them all in series, it would take 720 minutes. If you have a better home computer, you could (optimally) assign each of the 16 workers in your computer a frame, and they would each put the fire simulation on your frame simultaneously. With 16 workers, your scene would (optimally) take 45 minutes to finish. A super computer has thousands upon thousands of workers. If you had access to a personal supercomputer for your fire scene, you could do your fire simulation simultaneously on each frame individually. This means your scene would (optimally) be ready to watch in 1 minute. In real life, super computers are used for movies, physics, science, engineering, and website applications. If you have some kind of job that needs done, that doesn't depend on other jobs being finished, you can give each job to a worker, and each worker finishes simultaneously. Imagine back in the old days when they would mine gold by hand. If you are running a mining company and only hire one miner, you can only mine as much gold as that one person can mine. However, if you hire 100 gold miners, you can mine gold ~100x faster. A super computer simply takes large, complex tasks, like modeling the air flow on airplanes, or how water moves in the ocean, and divides the tasks up into smaller jobs, and gives those jobs to the thousands of workers so that your job can finish faster.",
"It's the same as a regular computer, but much faster. In past decades, the extra power was achieved by specialized, advanced hardware design. Today there is still some of that, but many supercomputers are built by linking thousands of normal computers (quite similar to one you would purchase at the store) together, and organizing their task so that the work is distributed among them."
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k84amf | What the difference between solving stego images in the wild and stego ctf images? | Technology | explainlikeimfive | {
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"CTF stuff is designed to be solvable in a moderate amount of time. In the wild is designed to not be solvable, and in fact is the opposite. For example, all you would need to do to prevent someone from recovering some hidden data is encrypt it with a secure password and encryption algorithm. Instant literally unsolvable problem. At least without a rubber hose. Also wondering how you \"know\" you have some hidden data. Steganography detection stuff is always going to have some false positive rate. The only way you know is if you actually find hidden data. Or someone tells you."
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k84fwo | What is the difference between front-end and back-end development/technologies? | Technology | explainlikeimfive | {
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"All the comments so far are non technical comparisons. So I’ll try give a high level technical overview while keeping it simple. I’ll focus on websites as that’s what your most likely asking about. Starting with the front end. The 3 building blocks to any website is your html, css and JavaScript. HTML is what structures the site, deciding where images, text, buttons and other common components should be placed. CSS is what decides how these components look. It applies styles. JavaScript is what gives functionality to the component. So take a button for an example. The html defines where in the page the button goes, the css decides what colour and size it should be and the JavaScript decides what happens when the button is pressed. Packaged together they create webpages. It’s up to the browser that you use how to interpret this webpage (you might notice difference between the same site on different browsers). So all that goes on inside your browser on your computer. It reached your computer by being deployed on a web server. Now the backend. When you click that button, it might need to pull in some additional data to show. Like when you click on a thread in Reddit, the website needs to retrieve all the data about that thread such as comments, karma etc. We don’t want to give every user every bit of data. That would be a privacy nightmare (account details for example). So instead you send a request to the backend server, which can talk to databases where all the data is stored and decide what to send back to your computer. So to summarise the front end is what the user experiences. What you see and interact with. The code and data in the front end comes from a web server, but is executed in your browser. The backend is more data oriented. It handles requests and talks to databases and other apis. It sits in a server and executes in the server. It sends data back to your browser for the front end code in your browser to handle. Hope that was clear enough. Any questions fire them below",
"Front end is what users see and interact with. Back end are the parts they don't see or interact with. A waiter and the dining room of a restaurant are like the front end. The chiefs, payroll, HR, and managers are like the back end. The user doesn't typically interact with the back end even though they are necessary to deliver the product: food."
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k877h0 | Why are screen resolutions multiples of 360? | I just noticed that most screens resolutions are multiples of 360 instead of straight numbers like 100 or 1000. What is the reasoning behind this? | Technology | explainlikeimfive | {
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"360 is a superior highly composite number, which gives it rather nice properties for even division. 360 is evenly divisible by all of the single-digit numbers except for 7 -- in other words, you can divide 360 evenly by 1, 2, 3, 4, 5, 6, 8, and 9. This is one of the advantages of using 360 as the number of degrees in a compass, for example, since it makes rapid division rather easy. It is also divisible by many other larger numbers, including 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180, and itself ... a total of 24 divisors. The superior highly composite numbers are very useful for having this nice property of being evenly divisible by many smaller numbers. Other common superior highly composite numbers include 12 and 60 -- these numbers are nice to use for purposes that require frequent division such as keeping time, since 12 can be divided by 1, 2, 3, 4, and 6, and 60 can be divided by 1, 2, 3, 4, 5, 6, 8, 10 12, 15, 20, and 30. Fun fact edit: an argument can be made that 12 is the ideal radix for a numeral system (the duodecimal system) instead of 10, which is used worldwide today because that's how many fingers (and toes) we have on our bodies. 10 is only divisible by 1, 2, 5, and itself, while 12 is divisible by 1, 2, 3, 4, 6, and itself. If you exclude division by 1 and by itself, it turns out that there are two numbers which have the best possible ratio for number of divisors compared to the value of the number itself: 6 and 12, both superior highly composite numbers which are divisible by 33% of numbers smaller than them (the maximum ratio among all integers). But since 12 has more divisors than 6, it makes sense to prefer it a little more. :) Also I found this on the internet.",
"Actually I think it's multiples of 240. NTSC used 525 lines per image, but only 480 (ish) lines were visible, and it was made from two interlaced images of 240 (ish) lines. I say ish because this was analog so manufacturers didn't have to strictly adhere to the official 486 lines per image. But 480 was the minimum; two 240 line images. And why 525 not 565 so you'd get 500 lines? I'm guessing it comes from having to cram the image and audio into 6 MHz of bandwidth, with a 4:3 aspect at 30 frames per second with equal vertical and horizontal resolution. So 240 makes sense for 480i, 720p and 2160. But 1080 is an odd resolution, at 4.5 times 240. But 1080 is nice in that it's 1.5 times 720 so scaling up and down is easier than it would be for 960 or 1200"
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k8av7y | What is happening on a molecular level when a computer is storing a memory? | Technology | explainlikeimfive | {
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"text": [
"Depends on what you are storing on. Hard disks? Nothing. Hard Disk Drives (HDD) Are disks stacked on one another that spin very quickly and store data using magnetization on these disks. Thats the reason they are so fragile, as if you drop a magnet it loses it's strength. If you drop a HDD, there is the possibility it shatters alongside the demagnetization, or the arm that magnetizes scratches the disk. Solid state drives are just like your ram, they load memory into them and use logic gates to determine if something should stay in data or go. This is further determined with how the memory is stored. Block, NTFS, FAT, or EXT4. On powerdown, the ram shuts down and the electricity in specific blocks return to default. In SSD, they dont and their locations are saved using logic gates and software. So, on a molecular level, again nothing is happening except electricity going through software and chips. The software gives encoding to the computer and gives values for every space of the chipset using voltage. Hybrids use a mix of both disks and chipsets, they are the middle ground and considered cheap. Be wary that they still break easily though."
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k8baej | Is wireless internet bouncing off of me, passing through me, or is it more complicated than that? | Technology | explainlikeimfive | {
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"text": [
"Wireless internet uses radio waves (radio frequency or RF), which are part of the electromagnetic spectrum. Radio waves are radiation, just like light, heat and radioactivity. The entire universe is completely awash in electromagnetic radiation, there is literally no where you can go to escape it. Yes, the radio waves used by wireless internet are either bouncing off you are are passing partway into you and being absorbed. The frequencies used by wireless internet won't typically pass *through* you though. The amount of energy that your body absorbs from these waves is extremely, *extremely* small. It does not cause damage. The kind of radiation that can cause damage is called ionizing radiation. Large doses of ultraviolet can also be harmful. The radio waves used in communication, even the very high frequencies are 100 times lower than the frequencies of radiation that are harmful to you. Very high amounts of radio waves *can* cause harm, but that requires close proximity and deliberate effort. For example if you took the door off a microwave and then stuck your hand in it while it was running. Or if you stood in front of an aircraft while it was testing its radar."
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k8bfxl | why is qwerty used on keyboards rather than abcde? | Technology | explainlikeimfive | {
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"text": [
"Could be wrong. But I believe it was to stop typists from typing too fast. Because back then too fast of typing could cause a malfunction or jam on a typewriter.",
"Back then we had type writers. Type writers used claws to punch a specific point with ink on paper, to create a sentence. If two keys were pressed at the same time, the type writer jammed. The original format was AZERTY, which according to some source I learned in keyboarding class: Because the vowels are close together, it was easy and quick to type on. This caused a lot of jams. They came up with a chart you could multiply your gross words per minute by two with how fast you could type (I dont think its possible to type 212 GWAM, mr.spencer -_-). To counteract this, a harder keyboard scheme was used to prevent jamming. New typer sharks in the industry found it hard to use, but possible. Jamming went down exponentially and broken type writers were less of an issue. Eventually it became standard and when moving typer sharks to computers, instead of reverting back they gave them the same format. Creating a universal QWERTY."
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k8dn5w | Whats a mainframe and why do movie hackers always “override the mainframe?” | Technology | explainlikeimfive | {
"a_id": [
"gexgu69"
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"text": [
"The term mainframe is an older term from the days when only big companies would have computers and usually only one. It would take up entire rooms with lots of different racks of equipment connected together to form a computer. It is simillar to how a modern computer is composed of a number of different components connected together however the components back in the days were huge. But like modern computers with their motherboards that house the CPU and main memory the computers back in the days also had a main frame to house these components. So the term mainframe was used for the big central computer. The other parts of the computers could have their own processors to control them but these were small in comparison and could not be used for much computing, similar to how modern computer components also have microprocessors to control them. The term mainframe have stuck around to refer to the IBM System z which is a direct decendent of the old mainframes of the 60s and is still used in the same way. However most computing have switched to lots of individual servers instead of one big one. So the term mainframe would make sense in movies set in the 60s, 70s and 80s. It could be possible to gain access to things like printers and modems, and you still can today. But getting access to the mainfraim would give the attacker access to all the systems in a company as everything would run on this single computer. However in the 90s and onwards it would be far more likely to face more diverse environments with lots of different servers. Even if the company would have a mainframe, and many still have one today, they would not be running everything. So gaining full access to the mainframe would not give you complete control any longer. But for a scriptwriter the term still sounds cool and is still accociated with somethging very central and important in a company."
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k8fh9t | What is the difference between a greenscreen and a bluescreen? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The obvious thing is the colour. In principle you could use any colour for chromakeying. However it is a big advantage if the colour does not appear in the foreground objects. This is why red or yellow is so rarely used as it can match the skin tone of humans as well as being a fairly common color for clothes and items as well. It used to be that bluescreen was the most common. This was because simple analog technology have a much easier time replacing colours then other colours. However as digital processes have become more advanced this have become less relevant and greenscreen have become more common. The advantage of greenscreen over bluescreen is that more foreground colors tends to be blue then green. In addition lenses refract different wavelengths of light at different amounts so they are often calibrated for a color in the middle of the spectrum such as yellow and green rather then the outer edges of the spectrum such as red or blue. This means that the reds and blue is often slightly out of focus compraed to the greens and yellows. Adding to this effect is that the atmosphere is blue so it will further scatter blue light. So a greenscreen gives a sharper edge between foreground and background elements."
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k8fvq7 | airplane propelled by ion thruster, how the heck does that work? | I read recently about an airplane that is powered by ion flow which apparently creates a forward thrust airflow which creates lift in the wings. URL_0 No moving parts involved, no fuel, no propeller, no engine. It is fueled by ions pulled from nitrogen in air . This technology is confusing to me as I am a non-scientist. Although I am 5 I have the intellectual prowess of a 12 year old. Is this thrust generation analogous to those old Sharper Image Ionic Breeze air filters which created a small air flow without any moving parts? And I assume although there is no fuel there must be A battery or solar cell to create electric current? | Technology | explainlikeimfive | {
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"> No moving parts involved, no fuel, no propeller, no engine. > It is fueled by ions pulled from nitrogen in air . Your mistaken there. Ion engine's naturally use fuel. Namely electricity. And xenon gas in space usually. Basically, you accelerate ions down a magnetic tube spending electricity, that makes them go very very fast. Its like any regular jet or rocket engine, throw something out the back = thrust",
"There are batteries, lots of them, to generate thousands of volts difference between electrodes along the wings. It just doesn't use fossil fuel onboard. Ionizing the air at the front and attracting the charged ions backwards creates a flow of air going to the rear that pushes the plane forwards. URL_0 As it comes from MIT and been published in Nature, a prestigious scientific journal, one can presume its kosher.",
"To answer the part people haven't answered: > Is this thrust generation analogous to those old Sharper Image Ionic Breeze air filters which created a small air flow without any moving parts? Yes, it's exactly like that.",
"In order for a plane to stay afloat, you need lift. This generated when you have air (or any gas, but let's stick wity air) moving over a wing. How that works is pretty well known nowadays. It doesn't matter to the wing whether it's the wing that moves through the air, or the air moving over the wing. So if you have a strong enough head wind, it's possible to have your plane lift off without it moving horizontally. I'm not sure how conventional airplanes do it, but I think they make the plane move forwards. And so the wings move through the air, generating lift. In this case, they have a high voltage wire that ionizes the surrounding air. That means an electron gets pulled from nearby nitrogen atoms, making them positively charged. As such, they'll be repelled by the equally positivzly charged wire. But by having a negatively charged wire behind the positive one, the atoms will move towards that one, and bump into other, neutral atoms/molecules, creating wind. And if, instead of a wire, you have a negatively charged wing, you can generate lift, as discussed previously. Finally, you will need a battery or other source of electricity in order to generate the high voltages required to make it fly. My first concern with this design, is that the thrust seems very limted, meaning you won't get a lot of forward velocity. In the video (which does a great job explaining it, imo), they launch it to give it an initial velocity, but I'm not sure how it holds up in longer flights. And another issue they'll run into, which they briefly touch on in the video, is that if you make the voltages too high, you won't just ionize the air, but create lightning. And -apparently- the higher you go, the lowze that voltage is (for the distance their electrodes are, because the breakdown voltage also depends on distance)."
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k8i3h7 | Could somebody make a video game or 3D environment in a computer that features more than 360 degrees to turn around? | Sorry, this is super hard to explain. Imagine spinning in a full circle and then be able to turn a bit further before you see what you saw at the start, before you turned around. Basically, what I’m asking is, could a > 360 degree computer-generated environment exist? Thanks for listening, if my question doesn’t make sense, please say so and I can specify. | Technology | explainlikeimfive | {
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"text": [
"Video games are not bound by the same constraints as the physical word. If you can imagine it, you can make it. You might be interested in some videos about non-Euclidean geometry video game engines. URL_0 URL_1",
"It's totally possible to create a game like that. In fact, there are games that use non-euclidean geometry (euclidean geometry is the one that you learn in school, non-euclidean is, well, any other geometry), where for instance if you turn four corners you're not in the same spot as you started, or there are rooms that connect in impossible ways. [You can learn more about non-euclidean games in general in this video]( URL_0 ).",
"The bigger question, is in a video game... how would you know if you turned 360 degrees or 720 degrees, outside of what you are seeing? & #x200B; Imagine the game is built with 370 degrees for a full rotation. You spin around with your mouse... back until you spun enough to see the same thing in front of you. Would you know you spun 370 instead of 360? Probably not, because our frame of reference is 360 degrees is back where we started at! So, your eyes/brain would never be able to register the \"full spin plus a bit more\" because it has no idea what 360 degrees is outside of visual cues! Though it might screw our brains up more in a VR type setup, that might actually cause mental breakdowns I could see."
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k8jfqw | How do car manufacturers prevent water such as rain, from entering the car engine when driving in rainy weather? I would assume that water in the engine is a big no no | Technology | explainlikeimfive | {
"a_id": [
"geyb2gp"
],
"text": [
"The hood minimizes water splashing directly on the engine itself. The air intakes are usually filtered, which would catch the few water droplets that made it in there. The fuel lines are all sealed to prevent fuel leaks, which also keeps water out. So there’s very little chance for water to enter the engine itself."
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k8slbw | What happens if I use a website without clicking "accept cookies"? | I saw Tom Scott's video about how cookies are how your computer talks to the server and all that and fingerprinting and stuff, but you're supposed to be able to say no to cookies, right? Most websites don't have an option to say no. I've noticed that I usually get a banner that just says "accept all cookies" at the bottom of the website, but you can use the website anyways. Knowing the world we live in, I assume the cookies are active even if you never click the accept button? I'm guessing there's some loophole thing that's like "by using our site you agree to cookies even if you don't push accept" or something. | Technology | explainlikeimfive | {
"a_id": [
"gezz016"
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"text": [
"Not all cookies are created equal. Some are tracking, some are authentication. If sites pop up and allow you to refuse, generally they are not authentication based and not necessary. I have been testing this and refused any site that allows me to and seen no performance degradation."
],
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k8txsv | My new apartment is already wired for cable internet. Does it matter which provider I get? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"No, any provider that services your address is likely to wire up your place as part of the installation fee (which they often waive). Just make sure you understand that first. Be warned that they may take out the wiring for a competing company."
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k8uewu | How does making a 3D model on my computer put so much strain on it, but rendering it in real time alongside a hundred copies of it in a video game work perfectly fine? Moreover, how does it take so long to render something that was already being shown and worked on? | Hope this doesn't count as a 'loaded question'. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"There are two factors at play here. First, and most importantly, model editing software is designed to make editing the model easy, and not to render hundreds of things at once. As such it may use more complex/slower data-structures and algorithms to store and display the model, if it helps with the editing. The second thing is that games often use lower quality assets (for performance reasons). It is quite common to edit a model in super high quality (simply because it's easier that way) and then create a much faster version to use in game. The in-game version could for example use normal maps instead of polygons for small surface details, compressed textures and coordinates as well as baked AO or lighting."
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k8wjk2 | Why do the newer call of duty games take up so much space? | Technology | explainlikeimfive | {
"a_id": [
"gf0rark",
"gf0xkbt"
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"text": [
"A combination of the use of photogrammetry, HD assets and poor compression and optimization.",
"Because of textures. Textures are photos or hand made photoshops of surfaces and textures that are put on object's polygons to make it look like the object in reality. In older games, back when technology was slower, it would take time for computers to compress, decompress, move, and apply textures to objects. So to save on performace, these textures were often low quality, that's why textures on older games look so blurry or pixelated, because the textures were low quality. Modern games, such as the newer COD, now use 4K textures, which are roughly 8 times larger than HD textures used in Black Ops or Modern Warfare. COD Black Ops 2 was 21 GB. It uses 720p and 1080p HD textures. Cold war is 95 GB on the XB1/PS4, which uses 1080p and 4K textures, and 135 GB on the XBSX/PS5, which uses 4K and sometimes 8K textures."
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k8xpki | How do sounds/music that seem like they go from one ear to the other work ? | Technology | explainlikeimfive | {
"a_id": [
"gf0z7p7"
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"text": [
"It seems like you’re talking about stereo sound. On almost all audio recordings, there are two different channels, one on the left and one on the right. Right plays through the right speaker and left on the left. These channels are usually synced to play the same sound but often we use the two channels to produce effects like echo, reverb, or “moving”. Imagine setting up two microphones on opposite sides of the room. Now each microphone is hooked up to someone’s headphones. Left and right. Then run across the room clapping. The person wearing headphones will hear the clap mostly in the right, then it will fade out to the middle, then to the left."
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k93w4b | - How does a dehumidifier work? How does it extract water from the air? | Technology | explainlikeimfive | {
"a_id": [
"gf1t36a",
"gf1tdb3"
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"text": [
"It’s basically a refrigerator. Air can hold less water as it gets colder. As the air goes over the cold coil, the water vapor forms on the cold coil(like on a cold drink glass on a hot humid day) and drips down to the bottom. It doesn’t cool the room down, because the heat that is removed goes back into the air.",
"A dehumidifier is pretty much an air conditioner set on low. Warm moist air is blown against the cold condenser coils and plates. As the air cools some of the water condensed on the coils and eventually drips into a collection area like a small bucket. As for how an air conditioner works, it's a pretty common question, i suggest searching the archive for that, a lot of people have already explained that."
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k950y9 | How does the metal ball used in nuclear weapons work, and how can it be handled without constant fear of exploding? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Because it won't explode, it can't explode without first having another explosion compress it to an insane degree. A subcritical mass can become critical when compressed. So a nuclear weapon uses a subcritical mass of metal, and surrounds it in conventional explosives, which trigger the nuclear explosive. Not to say that working with the stuff wasn't dangerous. It still killed plenty of people who worked with it. Just that you're not dealing with a live bomb until the whole weapon is put together.",
"The metal ball contains an amount of nuclear material that will only explode if it's compressed into a volume smaller than the ball. It's still Plutonium and super toxic, so you can't touch or lick the ball, but you can't make it go off. To make it go off you have to use very specific arrangements of explosives to uniformly compress it into a smaller volume, where it can do its nuclear thing. You can't compress it that much with your hand, it's a metal sphere.",
"you're probably thinking of the plutonium core. plutonium is a fissile material, which means when a neutron hits a plutonium atom's nucleus it will split, releasing energy and more neutrons, some of which may hit other plutonium atoms and cause them to split as well. the core is subcritical, which means this reaction isn't self-sustaining. not enough atoms will be hit in order to keep the reaction going. you can increase the number of atoms that split by surrounding the core with neutron reflectors or by compressing the core and packing the atoms closer together. when the reaction is fast enough that it sustains itself at a steady rate it's called critical, and when it begins to accelerate that's called supercritical a nuclear explosion requires the core to be so supercritical that most of the atoms in the core are consumed in a tiny fraction of a second, releasing all of that energy in an instant. it takes very specific conditions for that to happen. in old nuclear bombs like the ones dropped on Japan, they achieved those conditions either by pushing two pieces of fissile material together (the gun method) or by using a shell of explosives to compress the core down until it was dense enough to cause the required reaction (the implosion method) [like this]( URL_0 ) the faster the reaction, the more heat and radiation is released, so a core can be dangerous if it's used improperly and allowed to go supercritical, but there's no way for it to cause a nuclear explosion outside of very specific circumstances that will never occur outside of the nuclear bomb itself. that's why you don't need to worry about nuclear power plants exploding like nuclear bombs"
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k9h0fm | Why do some computer software updates require a restart and others don’t? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"If the update changes the code that controls the printer, you don't have to reboot because you can stop the printer, install the code, and start it back up again. However, if the code you want to update controls memory or storage, you can't just turn those things off during the update, because the computer will halt. So, these updates work differently, they don't change the running program (because that's dangerous). Instead they change the files on disk that are used to load the program when the computer boots. That doesn't change the running computer, at all, so you need to reboot for the change to take effect."
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k9jv89 | Why are hammers and nails still common in construction when battery powered drills and long screws are more efficient? | It has now dawned on me that drills (or battery powered screwdrivers) with long screws should be better on paper. Drill it in far enough, it gets to both boards. What stops that from holding then together? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Nails have a much higher shear strength than screws, they are much stronger. But screws stay in better. Put a nail halfway into a board and hit it sideways with a hammer, it will bend. Put a screw halfway in and hit it sideways with a hammer and it will break. So if the thing you are building is going to pull across your fastener, then a nail is better. If the thing is going to pull out on your fastener, then a screw is better. Don't get me wrong, I almost exclusively use screws. But nails are much cheaper, which is why I think builders still use them."
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k9m2ua | What is OpenVPN and how it is different from all other general VPNs? | Technology | explainlikeimfive | {
"a_id": [
"gf55nlb"
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"text": [
"Very often the word \"Open\" means it's an open source project. This is true for OpenVPN too. So the only real difference is the license. Everyone may look at the code, modify and copy it as they please. This means it's transparent what it does, and when people find a bug or safetye hole it can instantly be fixed."
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k9mfan | Why do CT scans spin in circles? I just don’t understand why you need to go into a really loud scary tube rather than just getting a standard x-ray? | I’ve been in a few CT scans and I’m terrified of them and need to know what they do | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"If you take an x-ray you get a flat 2d image. Is the cloudiness inside the lung, or outside the lung? You can’t tell on a flat image. But if you spin the x-ray and take a shot from every angle, you can connect those shots together and get a 3D model instead of a flat photo. Now you can tell depth and see structures/features that you wouldn’t have been able to see on a flat picture. Think the difference between one photo vs a diorama.",
"A standard x-ray is just a 2D image. Good enough for most things. A CT scan effectively takes a 3D scan so that they can get an accurate view of what’s actually going on inside of you. Why your doctors wanted a 3d scan instead of a set of x-rays is between you and your doctor, but it’s probably because you’ve got an issue that doesn’t show up well on X-rays. They may want to look at soft tissue, or an issue located where bones would obscure an X-ray’s view.",
"CTs are quick. MRIs take ages. Like the others have said, CTs and MRIs make a 3D model of the structures inside the body. X-rays are a flat image that generally only shows bony structures clearly. A CT will show most structures clearly but it’s still not a high resolution model. A MRI will shows all structures clearly and it is a high resolution model of what’s inside."
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k9mjsj | How are LCD, OLED, and Plasma screens able to specify a specific color for a specific pixel in the middle of a screen surrounded by millions of other pixels just like it? | Technology | explainlikeimfive | {
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"By using the third dimension. The pixel is supplied from behind with 3 supply voltages each to specify how much Red, Green and Blue should light up. How exactly the coloured light is mixed depends on the type (some make LEDs light up more, others put a \"shutter\" in front of a fully light up LED. But it all happens from behind the pixel)"
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k9ml2w | What is overcharging a battery? | I remember being told that leaving a rechargeable battery (e.g. cellphone's battery) charging after it's full will actually shorten battery life. Is this true and if so why does this happen? Also, I've heard with more recent batteries this so much or a problem as in ye olde days. If so, why? | Technology | explainlikeimfive | {
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"Why now and not earlier? Because nowadays everything that matters (phone, computer, etc) uses lithium batteries. They are more prone to overcharging issues but they are good for light power delivery. On the other hand, most devices nowadays can optimize charging to prevent overcharging. For example, if you charge your iPhone overnight it learns when you wake up so it can plan to reach 100% shortly before you start using it. It’ll chill for a few hours at ~80% and then go up to 100 in time for when you will start using it. Anyway, device makers have made workarounds to optimize charging and prevent battery damage."
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k9s021 | The different types of hybrid car | Is there an ELI5-type explanation of them, as I know what a hybrid car is, it's just so I know what I'm buying as hybrid is a bit broad a term. I know what mild and plug-in hybrids are at basic level, but aren't there a few types? | Technology | explainlikeimfive | {
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"Nowadays it's correct that there's basically just mild-hybrid and plug-in hybrid. They both have in common that they still have a normal gasoline or diesel engine. Mild-hybrid has a small battery and small electric motor. The idea behind that is that the electric engine helps the normal engine, for example when accelerating and therefore reducing the fuel consumption and emissions. The battery of a Mild-hybrid can't be externally charged and is only charged by recuparation, which basically means that the electric motor works as a generator when you roll or brake and charges the battery. Normally you can't drive a mild-hybrid purely electric, and if you can then just a very short distance. A plug-in hybrid usually has a much larger battery and a larger electric motor compared to a mild-hybrid. It can be charged externally (hence the name plug-in) and you can (normally) also drive purely electric. The battery capacity and power of the electric motor is usually far below that of a normal electric car though. The idea behind a plug-in hybrid is that you can use it like an electric car for short to medium distances, like driving within a city or for running errands, while you still have the comfort of having a normal engine for longer distances. A plug-in hybrid really only makes sense if you're able to charge it at home. If you're not able to charge the car on a regular basis then a mild-hybrid is better suited. It can be that some manufacturers have different names for their hybrid cars. But essentially it's either one of those two. Sometimes it might also depend on how the electric motor actually is built into the car. There's a lot of variety of how you can build a hybrid."
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k9wbmb | why does turning a computer off and on again actually solve a large number of problems? | Technology | explainlikeimfive | {
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"Most problems are caused by software getting stuck in a bad state it cannot get out of. Turning the computer off and on causes all the software to start fresh."
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k9zctt | How come when you’re watching a video on a device that you’re talking to someone with, they can’t hear the audio from the video but they can hear your voice? | Technology | explainlikeimfive | {
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"Devices have a built in feedback-damping algorithm that removes the sound they’re generating from the signal they’re picking up. Otherwise the two devices could just keep sending the same sound signal in an eternal loop. Hold a cheap microphone up to its own cheap speaker for an extreme example of what happens if this feedback-damping isn’t present."
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ka6pfw | why does computer OS take up so much storage when it's just mostly made up of texts of code? | Technology | explainlikeimfive | {
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"It's a lot of text. Like a whole whole lot. The Windows git repo is 300GB. Though to be fair this also contains a lot of old stuff. But this is also compressed. The source code for the linux kernel which is only a small part of a fully functioning OS in 2010 compressed was about 60MB, about 500MB uncompresed and compiles down to about 70MB. You can slim it down a lot if you know the exact hardware, but in general an OS will need to be able to run a wide variety of hardware that may or may not be present without needing to be recompiled. And will also need to have and support a wide variety of programs. That leads to a lot of code that isn't actually used on any specific hardware setup.",
"The base OS takes a lot less than 10-20Gb, the bloat comes with all the add-ons. The OS just tells the computer how to interact with basic peripherals, but people expect browsers, mail applications and so on to be standard.",
"There is actually very little text in the operating system code. If for example you examine the core file in Windows - the \\*.exe and \\*.dll files - it's about 95% microcode and 5% text. Large amounts of disk space is used storing graphical data - toolbars, icons, and such. In windows vast quantities of space is devoted to caching data that is stored elsewhere, for faster execution. Many windows programs that are stored in \\\\program files is also cached in subfolders of \\\\windows in order to launch those programs a tad faster.",
"I'm an information technology student at Latrobe University. It's not just code, it's a *shit-ton* of code. Apart from the OS kernel, there's also interface code, OS subsystems (like disk storage monitoring and allocation), legacy drivers for old or generic devices, manufacturer's updates for newer devices, built-in apps like browsers and mail clients, power user widgets (like the Windows command prompt and DOS emulator), client-side interface for all the different network protocols and network layers (UDP, TCP/IP, DHCP, web protocols like HTTP/HTTPS). All of that requires thousands upon thousands of lines of code to function properly. Then there's the GUI - all those buttons and sliders need code to tell those image assets where to be and how to behave, especially the more advanced stuff like finger-swiping and motion control. Exactly how much that is depends on what programming language it's being written in, what features it has, what system architecture it's going to run on, and what kind of backend it's going to have. To give you an idea of how much code that really is, [this is a restored photo of Margaret Hamilton]( URL_0 ), NASA software developer, standing next to a complete printed copy of the code she wrote for Apollo 11. **The shipboard computer she wrote it for had less than 100KB of memory.** A printed copy of Windows 10 would require an inconveniently large industrial warehouse to keep it in, and an equally inconveniently large printing shop to print it all!"
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ka6y85 | How MS-DOS became widely adopted at a time when UNIX and it's clones were popular before that? What caused the popularity of MS-DOS? | UNIX was a pioneer in Operating systems. and it's clones were popular some decades ago. What caused MS-DOS to become even more popular than *nix? | Technology | explainlikeimfive | {
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"Cheap licensing deal with IBM at a time when IBM, and later clones, were making their initial entrance into peoples homes.",
"UNIX was a multi user, multitasking operating system. It required a lot of hardware, back when hardware was expensive. MS-DOS barely did anything and it was cheap. It ran on computers cheap enough for people to buy. Here is a Sun price list from 1988. Thei machines ranged from $5295 to $23,850 URL_0 A PC with MS-DOS at the same time cost under $900. This was a time when the average household income was about $35000. There weren't many people that could afford to spend 15% of their yearly income on a UNIX computer.",
"It became more popular because it was the standard operating system on the IBM PC, which sold exponentially more systems than any competing business computers of the time. As for *why* IBM elected to license MS-DOS instead of UNIX, several reasons: * MS-DOS was cheaper to license than UNIX. * MS-DOS had much lighter system requirements than UNIX. The first IBM PC had only 16K of RAM and no hard drive. * The first IBM PC literally couldn't run UNIX as-is. UNIX, as a multi-user OS, was built around virtual memory management, but the original PC hardware didn't have an MMU to support that. The first Intel CPU to support the kind of memory management required by UNIX was the 80386. Note that the world would have ended up with CP/M-86 instead of MS-DOS if [its owner hadn't been such a terrible negotiator]( URL_0 ).",
"When the first 'home computers' were developed they had no hard drives so machines like the Apple ii had to load all programs from floppy disk essentially on boot. When the first IBM PCs were released IBM needed an operating system to go along with it. However the PC design process was rushed in an attempt to get to market to compete with the Apple. IBM was the biggest player in the computer market and was caught off guard by the Apple's success and didn't want to waste time making everything from scratch so they used off the shelf parts. This in turn allowed other companies to reverse engineer the PC and create 'IBM clones' or 'IBM compatibles' which changed the industry. Since IBM no longer makes PCs (they sold the entire product line to Lenovo) technically every PC today is a clone, there are no originals left. Similarly instead of making a desktop version of IBM Unix they turned to partner Microsoft to make a cheap OS in a hurry. Microsoft bought the rights to what was essentially a garage project called QDOS (Quick and Dirty Operating System), made a few changes and renamed it MS-DOS. However IBM foolishly licensed the OS instead of getting the full rights which is why Microsoft still dominates the OS market today. IBM executives probably thought that PCs would be a fad, or that they'd replace them with something proprietary later on (they tried and failed with the PS/2) and this lack of foresight cost them big time, but this lack of exclusivity (and the subsequent clones) did become the main reason why the PC platform ended up dominating the industry. Disk Operating System btw refers to the fact that the OS loaded from disk, or the Hard drive, instead of having to be loaded into memory manually on boot. Unix meanwhile was an expensive multi-threaded OS meant for business and wasn't suitable to be scaled down at the time. IBM sold the OS but sold it at a price that was only suitable for businesses so lone developers and hobbyists honestly couldn't afford a license for their home computers. (It wouldn't run on the hardware anyway) While Linux as we know it today hadn't been invented yet, although the free software project was already working on the concept it wasn't released in any useable form until 1991, ten years after DOS and well into the age of Windows.",
"Dos was simple to use “ user friendly” , the basic Disc Operating System came installed on PCs , profits were made from add on soft ware.",
"Unix didn't run on PC hardware. It needed bigger computers to run on, like mini computers and main frames. PC hardware at the time was limited to 1MB of memory or less by the intel hardware at the time.",
"MS-DOS has a better comparison to Apple than Unix. Unix was generally on minicomputers where DOS and Apple were for cheap microcomputers (your desktop is a microcomputer still). Bell/AT & T owned Unix, but it wasn't allowed to commercialize it (since 1956 for being a monopoly) until 1983 when Bell labs went away. DOS was on 2.0 by then and well entrenched in business america with Wordperfect, dBase, Lotus as the standard office suite of sorts."
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ka72r0 | How open-source is better than proprietary software for security? | Technology | explainlikeimfive | {
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"(1) Lots of people can look at the code. This includes people smarter, dumber, richer and poorer than those who wrote the code, and so it is more likely that errors will get noticed and reported. (2) No financial incentive to keep bad code even when it's known to be faulty (looking at you Microsoft) (3) More developers will make use of the code in their own projects, guaranteeing that weird side-cases and oddball scenarios are encountered more often and related bugs will be reported and fixed. (4) Open Source tends to encourage a sense of community and dedication to the \"craft\". This communal feeling makes some developers feel obligated to help fix bad code, even if they aren't going to use it.",
"Okay let's make an analogy- locks (like door locks that use keys). I'm going to sell you a lock. I'm going to tell you it's the most secure lock in the world, that it's all made out of high grade steel, that nobody can pick it. I tell you to use my expensive lock on your most valuable items. 'Why is it secure? Can I see the inside of one to understand how it works and how it resists being picked?' you ask. I say no- it's trade secrets. You have to trust me, the lock is welded shut so you can't open it and look inside. 6 months later, someone figures out that if you twist the lock with a screw driver and bang it with a hammer, it'll open on the 3rd hammer whack. You're now pissed off, your expensive 'super secure' lock is actually crap. That's closed source software- you have to trust that it's well-written and will stay secure. OTOH, my competitor has a lock to sell you. They don't just give you the lock, they give you the ability to open the lock casing and inspect its mechanical parts, and they give you the plans for the lock so if you want to improve it yourself, you can. Now, everybody from /r/lockpicking and other lock enthusiasts are poring over the design, looking for flaws, looking for ways to break in. They aren't paid for this, they just want the most secure lock they can get and working the bugs out of my competitor's lock is the easiest way to do that. So while I have my engineer saying the lock is secure, my competitor has thousands of amateurs and experts constantly crawling over the design trying to find problems, and fixing them when they find them. Pretty soon my lock is on version 3 or 4, but the competitor's lock has been improved dozens or hundreds of times. My lock has one engineer saying 'trust me boss it's secure', their lock has hundreds of lock people all saying 'we tried to break it and we couldn't'. Whose lock would you rather put on your valuables? The lock where one company promises it's secure, or the lock where hundreds of experts say it must be secure because they couldn't pick it? Open source is no different. With closed source, you have one company's assurance that it's well written and secure. With open source, you have the knowledge that dozens or hundreds or thousands of people are looking for security problems and will fix them if they find them.",
"It’s not necessarily. But the more eyes on software, the better. If you’ve got a skilled team making proprietary software they can have it locked down and pretty secure. Even better being proprietary in some cases. If you’ve got farmer John building the proprietary software you may have some problems. Same goes for open source. Popular project with lots of talented people involved, you should have a pretty good project. Bunch of farmer John’s tippity tapping and you can expect potential vulnerabilities."
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ka9g96 | How were computers powerful enough to send people to the moon, with just a few kilohertz and kilobytes? | Essentially what the title says - I was looking at a few early computers, and they don't seem much more powerful than a digital wristwatch today. Does that mean there were more analog circuits, did the astronauts have to do more work, or was code really that efficient for those machines? If so, why do programs today take up so much more space? | Technology | explainlikeimfive | {
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"The code was ultra-stripped-down, with as much work as possible done beforehand, so that it only had to do a minimum of calculation...and still, in some situations, the computer couldn't do things fast enough. Why is modern software so much heavier? * It has a user interface. The Apollo computer would give messages like \"1202\", and you had to know what that was, or you had to look it up. Modern software would say \"Warning: Execution overflow. The following tasks have been deprioritized to maintain critical flight functionality. Press here to reassign execution priority.\" * It's more flexible. The Apollo systems were designed for one mission, with very little latitude for anything unexpected to happen. With modern software...well, when was the last time you had a program fail because it didn't like what brand your RAM sticks were, or your motherboard, or your SATA configuration? Almost never happens. Modern software handles exceptions, and recovers from problems, really well - so well that sometimes we don't even realize it just saved our document, or our Reddit post. * Modern software is way more idiot-proof. People like me use computers every day and hardly ever cut ourselves, but the astronauts trained for months to get used to the Apollo systems, and still Armstrong and Aldrin didn't know what a 1202 was, and Conrad and Gordon didn't know what \"SCE to AUX\" was.",
"The computers in the apollo capsule of that time could do only one thing. In that case it was sending people to do moon. Modern computers can be changed to do many different things. This is mainly because of the programming was done by literally sewing together wires, rather than anything general purpose."
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kacngk | How does face recognition software work? | Technology | explainlikeimfive | {
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"Think about a digital picture. It's basically a square (or rectangle) of pixels, each of which shows a color that is represented by a number (look up RGB and color depth if you're interested). In mathematics, a square or rectangle of numbers is an interesting thing called a matrix. There are entire branches of math which deal with what you can do with a matrix (linear algebra). One of the things you can do is compute a \"fundamental vector\" of that matrix (eigenvector). Another related thing you can do is, rewrite a matrix as a sum of \"standard\" matrices, each weighted in a different way. This is the same concept behind things like 35=3 * 10+5 * 1 (where 10,1 are \"standard\" values and 3,1 are the weights aka coefficients), or even mixing ingredients in a recipe (10% of this, 20% of that...), except that it works on a matrix. As a result, you can say things like: this face (=digital picture of a face) is 10% of this \"standard face\" (say, Face1), 30% of that \"standard face\" (say, Face2), and so on. So if you have, say, 10 standard faces (called \"eigenfaces\"), you take a picture of a face and represent it as a list of 10 values: [0.1 0 0.2 0 .... 0.7] (meaning 10% of the first eigenface, 20% of the third one, etc). Then you store somewhere this and build some kind of database. As you analyze your target picture (say, from a movie), you analyze each face in this way to get the corresponding \"list of values\" (vector), then you find \"the most similar vector\" (again, math) in your database. Of course, there are a lot of complications in real life, but that's the gist of it. There are also other approaches, but ultimately they're based on the same mathematical concepts."
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kad0do | How are electrons moved by code? | Technology | explainlikeimfive | {
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"It's a layered system. Lets start at the bottom: Electrons are moved by opening and closing tiny switches electrically. They are called transistors. Many transitors form a circuit that can run machine code. Thats basically just binary numbers. 01101101 opens 5 and closes 3 switches to direct the electrons in a way to achieve some calculation. These machine commands are saved like a long list in your memory to form a program. Physically nothing else exists. But to organize it better for humans we started giving the commands names we can understand. This is assembler code. Every command directly translates to a machine commands, and your compiler simply has a mapping that ADD is linked to the command number that makes the CPU run the adder. And then we grouped several of these basic commands together and gave them a new name the compiler knows. This is higher language code.",
"Interesting question, and it would take a lot to answer in depth. Basically: - you can move electrons in a controlled way by generating electric current (current is by definition the flow of charged particles past a given region) - you can do basic things like bringing current/ \"resisting\" to current/somehow \"storing\" electrical energy with simple materials (wires, resistors, inductors, capacitors). However, more complex things require semiconductors (at least if you want to avoid vacuum tubes...) - Semiconductors are special materials which allow you to control electric current in a more complex way than \"regular\" materials. - Transistors are really tiny devices which, using semiconductors, allow you to control how current flows between three terminals. Among other things, they allow you to take an input current and output either 0 (no current) or 1 (some current) depending on a control signal you can manipulate. - You can use transistors to either \"process\" information (e.g. 0 - > 1, 1 - > 0), \"store\" information (store 0 or 1 somewhere and allow someone to retrieve it or overwrite it), or a combination of the above. You can also store and process more than one bit, obviously - Code is translated from a high-level programming language into machine language, which in turn translates into control signals to transistors used to store and process information in a certain way. - When you \"use\" a program, you're feeding input (itself something that translates into electric signals, from a key pressed on a keyboard, to a camera which translates pictures into 0s and 1s, to microphones,...) to a code. So, in a way, you're manipulating control signals which are fed to transistors in order to post on Reddit, look at a picture, play a game or whatever you like."
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kad7c2 | How is music played back, I don't understand how 0s and 1s can produce sound. | Technology | explainlikeimfive | {
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"> How is music played back, I don't understand how 0s and 1s can produce sound. There isn't really any practical difference between storing a text and storing information like \"stimulate a speaker with voltage x for y seconds and then with voltage s for t seconds\". It gets even simpler if the music is in a truly digital format, like a midi file: \"have synthesizer A play the sequence B C D E F G with time signature T\".",
"Sound is a mechanical wave. 0s and 1s are \"signals\" representing electric current (or voltage). As the input signal changes, a magnetic field is \"created\". This magnetic field \"dynamically\" attracts and repels a metallic coil, creating motion. This motion generates a mechanical wave, which ultimately generates sound.",
"Music being sound is essential just a complexly shaped wave. A wave can be represented with a number ranging from say 0 to 100 for every point in time. The thing about binary numbers is that any normal (decimal) number can be written as a combination of 0's and 1's. So this wave in decimal numbers can be converted to 0's and 1's to be stored in digital form.",
"The 0s and 1s enter into a circuit (digital to analog converter) and interpreted to produce analog (i.e continuous) signal. So for example 000 produce 0 volt, 001 produce 1.25 volts, 010 produce 2.5 volts. [Analog to digital ]( URL_0 ) Because of electronic components such as capacitors the transition between the voltage are smoothen. And when this analog signal enters a speaker it produces sounds The speed of changes in these analog waves and the changes in voltage value causes change in - speed- of the sound you hear from speakers and how loud/low the volume is"
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kaj9nb | How and why do rechargeable batteries tend to drain faster and faster as time goes on? | Technology | explainlikeimfive | {
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"Imagine a rechargeable battery not as one battery, but as thousands and thousands of tiny batteries. So if your rechargeable battery has 10,000 cells, when it's brand new let's say all of those are working. As you discharge and recharge the battery, some of those cells will start degrading and going bad. So maybe after 10 charge cycles you only have 9500 working cells. And after 100 charge cycles you might only have 8000. So if you started out being able to run a device for 10 hours off of this battery, after 100 charge cycles it might only last 8.",
"ELI5: Imagine a battery like a hole you dug in the beach sand. When you \"charge\" the battery, you fill up the hole with water. When you USE the battery, you slowly take water out of the hole with a shovel. Now, what happens if you fill the hole up too much? Water will spill out from the top right? And when it stops spilling out, there is a little path where the water ran out and now you can't fill up the hole with as much water because the path dug into the sand a little bit and made your hole a bit shallower. Basically, charging the battery to high levels causes degradation, but we like to charge the batteries to high levels because it gives them higher capacity. ELI'm Older: So batteries are what we call electrochemical devices. They are devices that have chemical reactions that produce electricity. Typically, the chemical reaction that occurs is the one we WANT to occur. This chemical reaction is \"reversible\" and causes no permanent effects to the materials inside the battery. We will call this reaction \"Reaction A (the good one.)\" While we LIKE it when only one chemical reaction occurs, this isn't... really true. In reality, there are MANY chemical reactions occurring simultaneously. Reaction A occurs in the most abundance, so it uses MOST of the reactants, but there is also Reaction B, C, D, E, etc. Now, electrochemical reaction SPEEDS are determined by voltage. A battery has a certain voltage, typically 1.2V. Just like the voltage in the walls of your house is 120V. So, at typical battery voltages, Probably 1.25-1.05V, Reaction A (the good one) is the dominant reaction. This is a good thing. However, when the voltage of the battery is HIGHER than 1.25 V or LOWER than 1.05 V, Reaction A is no longer the dominant reaction. High voltages enable (aka speed up) some \"bad\" reactions, like reactions B and C. These reactions are NON REVERSIBLE. They take reactants and they turn them into something that can't be turned back into useful reactants. So basically, these reactions REDUCE the overall capacity of the battery because the overall capacity of the battery is literally linked with how much \"stuff\" (reactants) is there physically. If you take away some reactants and turn them into something else, they can't produce charge anymore. A similar thing happens when you discharge a battery completely. Below say 1.05V, Reaction A (the good one) can't... happen anymore. There isn't enough reactants to support Reaction A. So, instead, reactions D and E happen. These reactions also produce charge, but do so in a non-reversible way, just like the bad reactions I talked about above. In the same way, they reduce the overall charge capacity of the battery. Now, the question you'll probably ask is \"Well why don't we just not charge batteries to super high voltages and not discharge them that far.\" And, in reality, that's a VERY good idea. But, if you did that your battery would only have a capacity probably half of what it is, and because of capitalism, each battery company competes with each other to produce the battery that has the highest capacity. Because of this, one company will say \"YEAH, OUR BATTERIES CAN BE CHARGED TO 1.4v\" all the while knowing that doing so will degrade the battery quickly, but it allows them to say \"Our battery has a capacity 2x that of our competitors.\""
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kakljl | What does happen in a phone when it's not charging but is still connected to the wire? | Technology | explainlikeimfive | {
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"Its either charging or not charging. Modern mobile phones are a bit of liars about charging and their battery. Generally what they do is charge up to 100%, then slowly discharge to 95%, then charge back up. Now this entire time, your phone will say 100% and charging, but as I said, they fib a bit about the reality of whats happening",
"Whatever the phone wants to happen. \"charger\" is a misnomer. The thing you plug into the wall is a power supply, that provides the right voltage to the phone. It's the phone itself that contains charging circuitry and the software it runs has control over what it does with the power coming from that cable. It can run from the cable, not using the internal battery at all. It can ignore the cable entirely and drain the battery as if it wasn't connected. It can supplement the cable with the battery, if you're using a weak power source. So really, there's no universal answer because it's up to the phone and the software that runs on it. It could even change after a software update. The important thing is that the \"charger\" doesn't force power into the phone -- the phone is the one that decides."
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kankz7 | How can the Nest thermostat and other IoT devices be available from outside my private network when no specific firewall rules have been set up to allow a session to be initiated from outside the perimeter? | Technology | explainlikeimfive | {
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"They establish a reverse tunnel (a.k.a. they phone *out* to the cloud server), which firewalls almost always allow. They keep the connection alive and the server can send messages back to them over this link.",
"Internet connections can be thought of like a phone call: one side dials a number and the other one just picks up, then both sides can talk all they want to. Normal home firewalls allow for outgoing calls, but won't allow incoming calls unless you set up a special exception. IoT devices allow the appearance of allowing incoming calls by instead placing their own outgoing call to a computer somewhere on the internet. That computer is run by the IoT company and has to be configured to accept incoming calls. When you want to control the device you send a request to that computer from your smart phone or other device, then it forwards the request to the IoT device. As far as the firewall is concerned there was only ever an outbound connection established, even though that connection was established to allow incoming data. This is relatively safe since it only allows a connection to a computer that a device in your home asked to talk to, not just some random computer on the internet asking to talk to your light switch or doorbell. That said, it's important to remember that \"the S in IoT stands for secure\" (and the R stands for reliable!) so exercise caution with just how many internet enabled devices you set up."
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kaqptu | How do "autosense" cycles work on dishwashers? | How does a dishwasher (or clothes washer) sense the amount of food/grime/stuff on what's inside? | Technology | explainlikeimfive | {
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"text": [
"They have a turbidity sensor on the drain line, when the water runs clear the dishwasher knows the dishes are clean and so it finishes the cycle."
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kaqst1 | Why does adding an emoji make my text split up into two (or more) shorter texts? | I accept the idea of character limits for text messages, but adding an emoji seems to reduce the allowed number of characters by about half, which seems like a lot to me. Do emojis just have too much data behind them or something? | Technology | explainlikeimfive | {
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"text": [
"Yes. Emojis are actually a code that your phone/computer is able to render in to the picture you end up seeing. Edit: they shouldn’t necessarily take up that much room but may depend on how the specific phone handles it."
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katfaa | How does a Submarine work? | How is diving and going back up controlled, what's important about construction? | Technology | explainlikeimfive | {
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"text": [
"Submarines use dive planes and ballast tanks to adjust depth. Dive planes are fairly straightforward. They're like airplane wings. When the sub is moving forward, angling them down pushes the boat down. Angling them up pushes the boat up. Ballast tanks are a bit different. Imagine a balloon underwater. It wants to float up. If I replaced the air in it with water, it would want to sink down. If we replace our balloon with a metal tank and attach it to a ship, we can adjust how buoyant the ship is by pumping water into or out of the room (and letting air fill the rest of it). If the boat wants to go down, you fill the tanks with water and either lose the air or compress it somewhere else."
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kaus8q | What will happen to flash-based sites on 1/1/2021? | I keep getting the warning that Adobe Flash Player will not work after 12/31/2021. Will there be another plug-in to download to be able to access flash-based content on websites? Will sites not use flash anymore? | Technology | explainlikeimfive | {
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"No, the plugin will be removed from browsers/operating systems and any website still relying on it will not function properly",
"The player will be removed and unusable. Unlike most situations when support, think Windows 7, Vista or XP, that still work fine they just aren't updated. Adobe will cease to function. Adobe will actively block it from running on devises that still have it and the major browsers will remove it. Their will be third party downloads and workarounds but those can be risky. Really, any site still using flash is years out of date."
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kavylf | How do we know that a very old painting such as the Mona Lisa is genuine? | I understand that there are techniques to date the paint on the canvas, etc. But how are the lineages/ownerships of these paintings over hundreds of years verified and kept track of? | Technology | explainlikeimfive | {
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"Well with famous paintings usually a continuous chain of custody is known about. Multiple people write about who originally bought or commissioned or displayd a painting, and the history can be tracked. The whole history of a painting and how it can be verified is called it's provenance, and museums keep catalogs of these documents.. It's a bit more involved with paintings that disappear for a while and then reappear in some attic or similar. And for lesser known works by famous artists. In cases like this lots of different forensic analysis is used to match the painting with other works by the same artist that do have a known chain of custody. This includes things like artistic style, age, materials used, etc. In at least one case one of DaVinci's works was identified by his fingerprint. There's a very famous pair of forgers John Drewe and John Myatt. One would forge the paintings, and the other snuck into and edited various museums catalogs to fake the provenance."
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kb0kpy | How are realistic animation movies like "The Lion King" made and rendered? | Technology | explainlikeimfive | {
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"That is a super complex question. The simplest answer is the right tools, the right skills, effort, and time. Disney has a lot of talented animators with a passion for what they do and a lot of specialized tools. However time and effort makes a big difference. Go on youtube and look up the \"astartes\" videos. They are a series of animations made by one man (with some smaller assurance here and there). Though if you watched the 5 episode 20 minutes ish long series you'd swear it was done by a team. Really it was done mostly by one man taking his time and effort into a project. I'd also recommend watching the videos of \"animators react\" by \"corridor digital\" on youtube. They explain a lot of the specific techniques."
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kb2spk | How are cinema-grade projectors / film techniques different from others? | I was curious about how these projectors are able to project images up to these huge displays with such a crisp and high-quality definition. What resolutions are these films being filmed / played at? These are the questions I have lol Thanks! | Technology | explainlikeimfive | {
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"I'm not a projectionist but I've spoken with some people who work with these projectors, and while I don't fully understand much of it I can give you a rough idea of how projectors work in modern cinemas. Most cinemas have transitioned to digital projectors many years ago (with the exception of true IMAX and other special film formats). They're huge, extremely expensive projectors with water cooling and a server that goes with it. The server contains the DCP which is a huge and complex file structure that contains the image and sound data. The projectors usually have a 1998 x 1080 resolution (called \"2K\" with a 1:1.85 ratio) and a bit depth of 10, though some bigger cinemas are starting to buy 4K projectors, and I imagine that soon it will become the norm. But transitioning to 4K isn't cheap so smaller cinemas are holding onto their 2K systems. Especially with smaller screens in smaller rooms, 2K works fine and the benefit of 4K won't be very obvious unless you're in the very front rows (which sucks anyway). The most obvious difference between cinema projectors and what you'd get for your home is the light output. The further away the screen is, the bigger the image can get, but the more light you will need. This however produces a LOT of heat and needs a lot of cooling. The bulbs are incredibly expensive and have a limited life span, so smaller cinemas usually dial down the bulb brightness to save some costs and extend the life of the bulb. But this of course results in a duller image. I guess there are regulations in place to prevent cinemas from doing this as distributers want to have control over the experience, but I've heard it's common practice to dim the bulb. So all in all, the resolution of these projectors is nothing fancy, but of course they have better optics and the projection screen itself is much more reflective (it has little shiny specs inside that help it reflect more light towards the audience but not towards the side). This allows the room to be darker while the screen is brighter. Combine this with high bit-depth images with no visible compression, good quality color reproduction, a ton of light, and you get a very clean looking image.",
"If you are wondering how the cinema projectors differ form the ones we use at home, this is how it differ. The cinema projectors are much more brighter because they a have to project on a larger screen . They have better optics (lenses) . The resolution is mostly comparable, older one 2k -DCI and the newer ones 4k-DCI. A lot of home projectors are UHD which is very close to 4K DCI. The most important difference is its ability to show vastly more colors and subtitle differences in tones than what a regular home projector is able to do. Also the source material is of much better quality. Non ELI5 explanation : Movie Theater films are mastered at 4k DCI resolution in a DCP-3 color space with very little compression. The projectors are designed to project this Image very faithfully. Media for home are regularly created at UHD in rec 709 and is highly compressed. This is vastly inferior to the theater master. Unfortunately most of the sub $2000 k home projectors don't even project this with the full color gamut. A few Epson 3 LCD 1080 projectors are an exception.",
"I work (currently furloughed) at a movie theater as the regional tech. Biggest difference between theater image and home image is bit depth and compression of the file. Most DCP’s (movies) for 2k film are 120gigs. Also, each projector is color calibrated often so color reproduction should be spot on. Of course the projectors are bigger, make more noise, require lots of cooling. Oh, the sound in the theater is calibrated often as well, at least at my theaters."
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kb6blc | What are the current issues using lithium-ion batteries without cobalt? | Just as in the title, thanks | Technology | explainlikeimfive | {
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"If I remember correctly, using iron is cheaper and better, and cobalt was used solely because of patent issues. This was expected for years, as the patent was due to expire sometime around now."
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kb7gva | How is a Project Orion-style nuclear pulse drive supposed to work of the charges don’t have any medium to travel through? | When they tested the concept in the atmosphere, the model could propel by surfing the shockwave, but doesn’t the shockwave come from a pressure wave propagating through the air? If I understand this right, nuclear explosions in space result in discharge of mostly electromagnetic energy, rather than kinetic energy because there’s no atmosphere to push a pressure wave through. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"[You can push stuff with light in space]( URL_0 ) just fine. Hard to find a better portable flashlight than a nuke in vacuum. However, Project Orion mostly planned on using the thrust from the vaporizing metal bomb body itself to throw a cloud of plasma against the rear plate."
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kb90wv | - If a cell phone screen can be 4k, why can't they make tvs out of multiple phone screens to make 100+k tvs | My phone is not 4k. It's like 2k but still, if they can fit that many pixels into a small phone screen, why is it that a tv can't be made the same way so there are literally millions of lines of pixels. Edit: I read this subreddit all the time and I've never read such condescension before. I'm not stupid or dumb, I just don't understand that if the tech to make it exists why are tvs not more advanced. Geez. | Technology | explainlikeimfive | {
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"text": [
"I'm no expert, but I would imagine the problem is that rendering a unified image across that many pixels would require so much processing power that it is not yet cost efficient to create it, even if it could physically be done.",
"To answer you question verbatim, they can make an 80 inch television with the same pixel density of a 4k phone screen. There hasn't been a TV made with that level of pixel density because there is no reason to make it. The only reason 4k phone screens are a thing is because people watch them 6 inches from their eyes. Too much further away than that and there is no benefit to paying for higher resolution.",
"Phone screens are so stupidly expensive per inch that you'd have quite serious issues finding a buyer for something like that. You'd also not get *any* benefits. 8K is already below the angular resolution of the human eye from the viewing distance of a TV. 4k+ content is functionally nonexistent. Also, resolution = > bandwidth. You aren't gonna put 16K or higher through any existing display connector standard. The TV you're proposing would need an entire bushel of cables and forget cable TV or streaming - the required bandwidth is such that you'd have to go and buy movies as boxes full of multi-terabyte hard drives. At 64k resolution, a two hour movie would be approximately 32 Terabytes, which is some 800$ cost in just the pair of 16TB hard drives to sell it on.",
"Why do you assume that they can't, as opposed to that they simply won't? Unless there is content to justify a resolution at that scale, or at least close, to what end would this be done? A 4k Blu-ray will look the same on a TV with 100,000 pixels across as one with 3,840 across.",
"One problem would be constructing a panel that large with all of the LEDs working correctly and in sync. I suppose they could take 100 4k phone screens (e.g. 10 wide and 10 high) and put them together to form a large display. That would be awesome. You'd quickly run into a data problem though. You would need enough computing power to render your games at such a high resolution. And you would somehow need to acquire 400k video content. Maybe use the same strategy to use 100 4k cameras to make one large 400k camera?",
"Don't sweat the condescension, reddit can be full of recalcitrant thundercunts at times but there are good peeps hiding among them. I am glad you got your answer. It was something I had never thought about but your question made me genuinely curious and because you asked it now myself and others know the answer. Thanks for asking, thanks to everyone who gave an informative answer and down with the lazy shart jockeys that don't help at all."
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kbb3p2 | How do graphics cards improve graphics? What makes a bad graphics card different from a good graphics card? | I’m trying to see what exactly makes a graphics card work or improve FPS and looks in a game. | Technology | explainlikeimfive | {
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"Good cards do more work per unit time than poor ones. The game can measure this as FPS, and to work with a poor card some stuff gets left out. While they try to leave in the most important stuff, more is better.",
"More processing power to do calculations and renderings faster, which both means you can render a scene faster (more FPS) and with more computationally expensive and visually appealing settings. More Video RAM to store textures and models in memory on the card itself, so everything the card will need to render a scene is in memory and won't need to be stored in general system RAM or on the hard drive Different technologies/features such as optimization for things like Ray Tracing, or different versions of DirectX (widely used graphical API) that support different features.",
"The amount of data it can process in a given time period. Every frame you see in a game involves millions of calculations. Geometry needs to be manipulated. Textures mapped to the geometry. Lighting and shadows and reflections calculated. Motion blur. Color correction. And this needs to happen at least 60 times per second. This gives a breakdown of what happens when drawing a single frame in GTA V: [ URL_0 ]( URL_0 ) The more expensive \"good\" graphics cards simply have more and faster processors and more memory than the cheaper ones."
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kbcqv6 | Why do memory sticks sometimes get corrupted when unplugged improperly? | Technology | explainlikeimfive | {
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"Imagine you're writing on a pad and someone pulls the paper away from you before your finished.",
"More or less for the same reason why whatever you were saying may get cut off if you get thrown out of a place by a bouncer, rather than if you get to finish things up and say goodbye. The computer is doing things with that storage device. You just yanking it in the middle interrupts whatever it was doing, which may be writing a document. And if the device contains half a document at that point, then that's all you get. With many file formats, half a file isn't a valid file, so you get nothing."
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kbdoc0 | what is difficult about patching bugs in a video game? meaning why is it easier for companies to patch bugs after the release of the game rather than before?. | Technology | explainlikeimfive | {
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"You seem to be under the belief that they don't also fix bugs before release. Do you think they just leave hundreds of bugs, maybe thousands that would be found and created during the development process there until they release it? No, they do as many as they can before releasing it. Then once it's released there will be new ones that appear. New combinations of hardware and software they didn't test beforehand. They'll have to fix those now. And perhaps bugs that weren't a priority turn out to actually be bigger than they expected. Or they couldn't reliably reproduce or solve them. Or they just didn't have time.",
"There is no real difference in difficulty when it comes to fixing bugs before or after release of a game. The difference is in being able to find the bugs in the first place. The more people you have playing the game the better your chances of finding a bug. When it's just the internal developers and QA team working on finding those bugs they may miss obscure ones because they only occur under really unusual circumstances that they don't test for or they only occur on some specific software/hardware combination that they are not using as part of their testing process. Performing really in-depth testing of a game can also be very expensive and time consuming. Years ago such testing was necessary though as once a game was released it was pretty much impossible to patch anything. Now days with the rise of the internet and digital distribution patching a game after the fact is easy. As such, the company can save some time and money by cutting back on depth of testing done and instead rely on their ability to quickly patch any problems that are discovered later.",
"Some of the bugs may just not have been caught. Playtesting is an organized affair to specifically test various things, and not a lot of extra time to screw around randomly. Once you sell the game to a million people, there are suddenly a lot more people doing whatever they want. This discovers lots of bugs that were there but not tested for. Everything from holes in the world geometry to finding out that talking to a random quest giver makes Lord Hufflepants disappear and the player is stuck with the MacGuffin Stone in their inventory forever. This is one of the reasons we have day one patches. The suits make the call that version 1.018 is the official release version, and all subsequent bug fixes go into 1.019 that will become the day one patch."
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kbdp3a | how do game developers create games with graphics so intense that not even the latest tech can achieve those graphics? (Like even the rtx 3090 struggling with CP2077) | Technology | explainlikeimfive | {
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"They could create graphics that take 50 hours to render each frame of they wanted to. In many ways it's more difficult to do the opposite, having a game that runs well on a wide range of hardware. Generally speaking, targeting future hardware isn't too tricky as the progress of hardware is relatively predictable, at least in terms of trends. Offline renderers - the sort they use to make animated films and such - are fully of features and settings that aren't even close to being possible in real time yet. What makes it into games - even things like Raytracing - tend to be hacked about versions of what's in offline renderers, designed to run in real time. The better the hardware, the closer to the \"real thing\" they're able to get, but real-time hardware is so far away from being able to render these things in real time that it's not like they're running out of stuff to do.",
"Pretend I am the game, and pretend you are the GPU*. My job as the game is to describe to you how I want you to draw a picture. When the game's graphics settings are \"low\", I show you a map of a 3D world, and I tell you where the camera is and where it's pointing, and I tell you there are 40 trees and rocks in the world, and where they are, and I tell you each tree has 10 branches and 50 leaves on it, and I tell you where those are, and I give you three photos of tree trunks and 20 photos of leaves to help you draw them. You draw all of this in 1/30th of a second. Since you can draw that quickly, you can do it 30 times in 1 second, so your game can run at 30 frames per second (fps). When the game's graphics settings are \"high\", I do all that, but I tell you about a lot of little indentations and flaws on every tree and rock you have to draw, and I tell you each tree has 500 more branches and where to draw each one of them, and 1000 more leaves, and I give you 300 more photos of leaves and tell you where to draw them. I also tell you I want you to do math to figure out how much the sun is lighting up every part of every tree and rock, and then to figure out how much the light reflected from those parts lights up other parts, and draw all the light correctly; and I tell you there are 50,000 dust motes in the air, but instead of telling you where they are, I tell you where they were a long time ago and I give you math formulas to figure out where they are now. And I tell you that you have to do math to figure out where all the shadows are from the sun, but also the shadows from reflected light from other trees and rocks, and I make you draw it all. This takes a lot longer to figure out and draw. If it takes you 1/4th of a second to draw all that, you can draw at 4 fps, and you say \"screw this\" and switch to low graphics like an FPS gamer does. However great graphics cards become, it will always be possible for games to bring them to their knees by demanding more and more detail and visual effects in every frame. *Actually you are a combination of DirectX, your card's graphics drivers, and the GPU, but I wanted to be simpler."
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kbhxn1 | How do pirates make money? | I have never personally pirated anything but I had a friend who did a lot and I'm curious how they pay to store 100s of those 70GB + games and give them out for free, especially the ones that don't install ransomware or whatever | Technology | explainlikeimfive | {
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"If you mean the people who break the security on games then a lot of them do it for fun and fame among the community. Some do it to share with people who otherwise wouldn't be able to afford games. Some of the pirate sites run ads so they make some money when people visit them. If you mean the people putting them up for download then they often don't pay for the storage. They put them on 3rd party storage websites and get paid when people download them because those sites have ads and they share some of the money with the people uploading the games. Also, there are torrents which are basically a free way to store and distribute games."
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kbpgpg | How do hybrid cars work? Can these cars run on gas and electric independently Like basically have 1 gas engine and 1 electric engine? Or do they work together to get better performance? | Technology | explainlikeimfive | {
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"There are two (broad) approaches that a car manufacturer can take for a \"hybrid\" gas electric vehicle. One is where the gas engine and electric motor can both drive the wheels of the car. So, in a way, independently as you put it. The electric motor and battery in this design is usually small so can probably only power the car without the gas engine at slow speeds. The electric motor is designed to save gas (say cruising) or for additional power during overtaking - which allows the manufacturer to put in a smaller gas engine. Think of it as a gas powered car with electric motor supplementing. The second approach is one where the car can only be driven by the electric motor. The gas engine is used to generate electricity to charge the batteries. In this case, to your question, the car cannot be run on the gas engine. The electric motors have to be more powerful and typically these kind of hybrids have larger battery packs too. This is an electric car with a gas engine range extender."
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kbr53s | What actually happens when you “restart” a machine - does it switch off? If so how does it start itself again? | Technology | explainlikeimfive | {
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"Yes, it cycles off and back on, and just like a computer. The power button isn't like a light switch, it has a circuit it connects to that's on full-time waiting for a power button signal to turn other stuff on. That same circuit can be made to handle turning off and then making its own start signal without a button press"
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kbs794 | How is it possible that very large cities, such as NYC or Tokyo, are able to supply fresh water to the whole city? How does the water supply not run out? | Technology | explainlikeimfive | {
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"NYC’s water comes from large reservoirs located upstate, meaning in the areas of New York State located north of NYC itself. Those reservoirs are up to 125 miles away and deliver over a billion gallons a day to the 9M+ residents of the city. Many people consider the high quality of the water to be one of the reasons that bagels and pizza in NYC are so delicious and there are some reports that shops and restaurants outside the city will even have the water sent to them so that such quality of flavor can be available to NYC transplants looking for their bagel and pizza “fix” in areas such as Vegas and parts of Florida! I lived in NYC for 14 years and never felt any desire to drink bottled water. [wiki]( URL_0 )",
"You may not see it from a map or satellite, but there are natural rivers that run through Tokyo that the city has been built on top of. The rivers are still there, they're just underground. Also Japan get some serious monsoon rains and Tokyo built a [massive flood system]( URL_0 ). I don't think the flood system itself is used as a water supply, but the rains fill up massive water reservoirs that are both above and underground. This is what supplies water to a city."
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kbu8xr | How does Zoom know not to send back audio that comes out of my computer’s speakers? | Technology | explainlikeimfive | {
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"text": [
"Zoom knows which sounds (aka voices) it sends to you. When it sends your voice back to your chat partner, it adds sound waves that directly oppose the sound waves of those first voices. That cancels them.",
"This is called [echo cancelation]( URL_0 ). Zoom knows what sound it is sending out your speakers, so if it detects that sound coming in your microphone, it doesn't send that sound to the other people."
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kbucnb | How does SEO spam work? Here's an example: r/goosofa | URL_1 URL_0 How does this spammer benefit by creating a subreddit and loading it up with links to his spam site? Search Engine Optimization - So by flooding his sub with links to his spam site, I may come across it somehow when I use google to search for something? I want to see this in action. Show me how searching for something gives me a link to this spammer's website. | Technology | explainlikeimfive | {
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"text": [
"In theory, Google sees that Reddit is linking to that website a lot and assumes it must be a really useful website (like Wikipedia or YouTube). Sure, they could make their *own* website and spam links on their own website, but Google wouldn't count those links for very much because it knows that their website isn't a useful one. Google treats links as more important if they're on a more important website."
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kbuwjf | How do space heaters start pumping out warm air right away but car heaters take some time to warm up? | Technology | explainlikeimfive | {
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"text": [
"Space heaters typically use electricity running through a heating element (basically a resistor) to create heat. When the power is switched on they immediately start heating up and reach temperature within moments. Automobiles use the waste heat from their internal combustion engine to provide cabin heating. Burning fuel in the cylinders heats the engine which is cooled by fluid circulated to a radiator, and some of the warmed air is diverted to the cabin. In order for the radiator to produce warm air the engine itself must have time to warm up and it is a large amount of metal. This takes more time than with an electric heating element.",
"Ready to be corrected, but don't car heaters rely on the engine warming up?"
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kbwglf | How do the non-removable security tags on supermarket products work? | How do the small security tags (usually stuck on with adhesive) work on things in supermarkets, like meats, dvds etc? They don't get removed after purchase, so how come that individual item doesn't set of the alarms even though the tag is still on it? | Technology | explainlikeimfive | {
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"text": [
"Stickers and such need to be deactivated at the register. You probably don't even notice it, but your cashier runs it across a pad or other such scanner and it deactivates. If it hasn't been deactivated, it'll set off the alarm.",
"At checkout the tags are passed over the deactivation system that is usually built into the register scanner. Once that tag is deactivated it won’t alarm when you exit and the tag can’t be reused.",
"Each tag sends out a radio message when a reader lights it up with radio frequency waves (the reader's signal also provides the power for the tag). The message is a large number, large enough that it is astronomically unlikely you'll find two with the same number in the same shop, burned into each tag when it was manufactured. When the shop gets items with such tags (or sticks them onto stuff), the number of the tag gets entered into the shop's database. When the cashier pulls the item across their reader, the number gets removed. If a reader in the security gates detects a tag with a number still in the inventory, you get an alarm."
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kc5bjx | 911 is the emergency line for the whole US, how is it that when you call you’re not calling one centralized place? | Technology | explainlikeimfive | {
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"What actually happens is that when you call your local phone provider (land line or cell phone) routes you to the closest emergency call center. Think of it like a shortcut. In the cell phone network this is more complex but happens by figuring out which cell towers you are closest to and routing you based on that information.",
"Your call actually goes to a switch, which decodes the number you dialed and then sent to another switch. This happens MANY MANY times until you're finally connected to your intended recipient. When you dial 911, it goes to the switch, and then the nearest 911 call center with your phone number and approximate location details. The call center then calls the appropriate police station based on your location (usually the one you give them if you're able to speak)"
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kc7hpj | How do professionals in fields that change quickly over time (health, technology, etc.) stay certified? | Say you have a medical doctor, or someone who studied computer science (or another field based in science) who graduated with their degree in, say, 1980, and are still working today. Is there any sort of retesting or recertification as new information emerges? Our understanding of STEM, health, and many other fields are constantly changing. Things we believed to be factual in the past often times aren’t in the future. So do professionals in fields like that, who began in these fields decades ago, actually have to learn new things as we learn more? Or can they just keep using outdated techniques? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"continued educations. a lot of fields will pay for you to take classes and courses to keep up with the evolution of science/tech",
"My field has continuing education requirements . X number of hours ever 3 years or you lose your license and have to take the exams all over.",
"I work in cybersecurity. Every day I check for cyber related news, check the recent vulnerabilities, and learn about anything of importance. That’s usually just in my personal time before I start work. I also am attending webinars and conferences when I can find the time. Those generate continuing education credits. I take additional courses both to reinforce stuff I already know and to learn new skills. I’m not 100% where I want to be in my career yet so I also spend a good chunk of my personal time studying for the next certification. Getting additional certifications and the courses also generates continuing education credits."
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kcb8qp | How can we always drive ‘first person’ in reality, but it’s easier in ‘third person’ in video games? | Most video games that involve driving are, by default, in ‘third person’ and this makes it easier to drive vehicles. This seems counterintuitive since we only ever drive in first person. I’ve tried first-person in games like *Need for Speed* and *GTA* but it’s difficult. | Technology | explainlikeimfive | {
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"In videogames you can't feel either the weight or acceleration of the car, and wilst you can adjust the audio to be surround and the fov to be more in line with our own it will still be off since it's a screen. Basically it comes down to spatial perception, and how those things affect us.",
"In reality, you rely quite heavily on peripheral vision to give you a sense of your position on the road and what other road users are doing. In games your field of view is much more limited. Moving to third person gives you that extra information that is missing.",
"My assumptions, based on lots of gaming hours. You might need to try virtual reality to tell for sure, in VR games the camera is tied to your head movement, and the screen is really close to your eyes. Very similar to real driving. & #x200B; In regular games, the screen is far from you, even when you change the view to \"\"inside the car\"\", you still feel in a 3rd person view.Also, when you move your head nothing changes. In real life moving your head will cause the \"camera\" to move, this helps with deph perception. I presume those differences cause the brain to feel weird when driving in a game.",
"Well, first of all, taking the GTA first person example...in reality, my head doesnt automatically snap back to center when I turn it left or right. That and peripheral is crap in GTA first person."
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kcezt5 | What makes one companies AA batteries better than another’s? Ex. Energizer vs Duracell | Technology | explainlikeimfive | {
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"I’m no expert, but my understanding is that there are several elements that go into a battery, like graphite and magnesium and zinc. The level of refining and purity of those elements affects the capacity of the battery. More refined elements mean more stored energy and a more predictable lifecycle, but comes at the cost of more expensive equipment and processes and that drives up the cost to produce the batteries.",
"Also, when a company introduces a new battery that purports to be \"advanced\", is it truly? Or have they simply degraded the base version's deliverable power and slotted the new battery at or slightly above the former one? Not meaning to sound conspiratorial, but I've noticed base versions of batteries not lasting as long as I was used to. And all major companies have come out with upgrades to the base...hence the question.",
"Advanced batteries could be a different battery chemistry. There are some really cool things being done with solid electrolyte lithium batteries. However, it is unlikely that you will be able to purchase these in the AA form factor any time soon. For right now, the differences are minuscule and will likely continue to be minuscule for one simple reason. If one company is using a certain chemistry, what is stopping the other from using the same chemistry? Probably legal issues. What is the solution? Make it slightly different with as little performance penalty as possible but using the essentially the same chemistry under the hood. Where performance differences are seen it is usually between batteries of different generations which often use wildly different chemistries. Example: alkaline vs lithium",
"First, make sure you are comparing the same chemistry. They could be zinc-carbon, Lithium, NiMH, Alkaline. They all differ in capacity and sometimes voltage.",
"Honestly 99 1/2% of the difference is marketing. Many products are made by one giant company. One single factory will make 3 or 4, or more versions of the same product. The difference is color, labels, and marketing. Young people don't want to buy what old people buy. Hip people don't want to buy what stogy people are buying."
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kck7xg | why do video games usually have players and objects fall at a set speed instead of increasing in velocity over time like Portal and Portal 2? It would make a lack of air control and high fall damage seem a lot more fair. | You wouldn't even necessarily need to accurately simulate 9.8m/s^2. You could just switch between different preset falling speeds with every half second of hang time. You could even simulate this only on heavy objects and actors, or just the player character alone. | Technology | explainlikeimfive | {
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"text": [
"Games generally do have players and objects accelerate as they fall, but they might reach terminal velocity sooner than what is realistic. I don't see how changing that would make a game better.",
"It just depends on the engine used. Example: Source does not do this because they calculate fall damage via velocity."
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kcm33x | Why aren't widescreen TVs made with a 1.85:1 ratio? | 1.85:1, one of the original standard widescreen cinema ratios, predates the 16:9 (~1.78:1) ratio that is the current standard for TVs. You'd think 1.85 would serve the same purpose just as well as 1.78 because they're nearly identical, so why was 16:9 even developed and chosen as the new standard TV ratio over 1.85? Edit: I probably should've phrased this differently. The answers I've gotten so far aren't really explaining why 16:9 is such a good compromise when 1.85:1 is already almost identical to it. Why not just use 1.85? How isn't that already a good compromise between 4:3 and 2.39:1? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"It's a compromise. Lying between 4:3 of TV and the wide picture cinema format. It's easier to display both as 16:9 with minimal loss of picture.",
"Actually it’s the only ratio that fit into all other ratios making it super easy to cut content to fit. URL_0 It’s a compromise format."
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kcqabh | How do people perform tasks inside an MRI machine like read books or play saxophone or listen to music? Aren't they very small? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Mri machines are usually pretty small yes. But that doesn't mean they can't be wider physically, just that making them wider makes an already expensive machine more expensive. And they can be made more like a ring instead of a tube of you don't mind some loss in image quality. If you only want to stick a person's head inside a machine while they are reading that should be doable with a machine designed to fit a person's torso. It also helps somewhat that the machine has to be round by construction and people's bodies tend to be more flat giving you a bit of room. If you want to MRI two people doing \"things\" you need both a big mri and relatively smaller people willing to be a bit cramped. What's also interesting is how special instruments get made so that you don't have metal inside the machine. Like you can make a harmonica, or horn out of plastic. It won't sound good at all, but it also won't catch fire in an MRI and is enough for the science to get done. Like here's a video of a guy playing a \"cello\" in an MRI. It's not at all a real cello, it's a plastic mockup with a real short bow and fancy fiber optics sensors to carry signals to electronics mounted away fr the machine without metal. URL_0"
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kcrx12 | Why were telephone/headphones cords spiraled back in the days, but they're straight now? | Technology | explainlikeimfive | {
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"It used to be that phones were connected to a landline and therefore screwed into the wall, or at lest could not be moved far. So in order to allow people to walk around with the headset without tangling it the phones would have spiraled cords that would stretch out when needed and contract when not. This allowed people to walk around the room while talking on the phone. Nowadays phones are all wireless in some way or another. So if you want to walk around you can just carry the phone with you and there is no need to vary the length of the chord. It does not get tangled as easily. If you are sitting at a computer you are more or less locked to the screen and can not move around anyway. So there is no need for a spiral chord there either. That being said you can get spiral chords today as well. However they are more expensive and bulkier then their straight equivalents so most people do not bother with them.",
"It was about the capability of length rather than now where people know exactly how much they will need and also the expense of lengths of cable"
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kct0gs | is it more secure to use a passphrase over a password | I use a lot of passphrases for my passwords, their easier to remember and apparently as secure as a password, but I was wondering if the XKCD comic is still right, considering recent advances in processing power. I’ve seen lots of questions asked like this but they are all confusing. | Technology | explainlikeimfive | {
"a_id": [
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"It essentially boils down to the longer your password is, the safer. Brute force methods attempt to guess your password by trying each possible character at each position. For example, if your password is 3 characters long and only contains letters, a brute force algorithm would only need to guess 26 × 26 × 26 combinations. Each additional letter makes 26 times more combinations to try. Actual passwords of course can contain numbers and symbols which makes this number larger (and your password safer)."
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kcur9m | why do game or website servers have to go down for maintenance? What’s being done during these times and why does it require them going offline? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Seen many car mechanics fixing a car that is currently running?",
"Imagine that when you were posting this, Reddit decided to update their site and replace the post button and functionality behind it. When you clicked the post button you clicked on the old version because you already had the site loaded in your browser. This returns an error because the new site doesn’t recognize the old button anymore. Your post is lost and you’re frustrated. This is one of the reasons. To avoid users interacting with the site while update is taking place.",
"Replacing a broken component, rebooting for efficiency, upgrading in the rack, software updates, etc. a multitude of reasons would make a server go down for maintenance. My bank, for example does it about once a month.",
"The internet is just a bunch of computers added together to form one giant network and so \"servers\" are technically just \"regular\" computers. Where I put regular in quotes because due to the fact that you're not really using the server as a idk gaming PC for yourself, but mainly use it to send and receive data packages (like the stuff that happens in the background when you visit a website), you probably cut on the parts that would be necessary for a graphical user interface and instead invest on the parts that are necessary for processing and networking. Still essentially it's just a computer that shares some files and folders with the rest of the network. The only difference is that you keep it running 24/7. In order for other people to be able to interact with a website it must be \"online\", so you're computer must be powered on, all the time. That is stressful for your hardware and from time to time you'll have problems with \"wear and tear\", things might get too hot or simply fail and you need to replace them. Also over time your hardware will simply get old. Like imagine you would use a 20 year old computer to provide a website. It might be still working but it would be rather slow or limited on both ends. So from time to time you might want to copy the data to another machine and use that instead, for which you might need to unplug the one and plug in the other to the internet. Or not just hardware but also software updates. If you run your computer on the same operating system for years on end, chances are there will be a lot of bugs and exploits being found over time that make your system pretty vulnerable and as said it's always online. So you need to keep your system up to date, but at the same time that might mean that you have to restart close down and restart your application for all the changes to be added. As said at the end of the day it's an almost regular computer with all the quirks that come with that."
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kcwl7t | Youtube Outage | Technology | explainlikeimfive | {
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"text": [
"It seems to be that youtube itself isn't down, just the entire Google login system is. Since you are signed in on your normal browser, then this causes an error there, but you aren't logged into incognito, which allows youtube to work.",
"This could be explaned by an issue with the authentification service which is used to identify who you are. The youtube website and all other google websites assumes that this service is always available and instead of giving you an anonymous version of the website when you are logged inn but it can not confirm this, like you would when you were not logged inn such as when opening incognito mode, they give you an error message instead. This can be understandable for services like gmail or drive which does not have any data to show anonymous users. However it can likely be considered a bug for services like youtube."
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kcz414 | How do game developers carry out patches and updates to video games on each consumer's console/PC? | Technology | explainlikeimfive | {
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"text": [
"The game/client is programmed to connect to a central server, usually when you start the system or game up, and check to make sure the version ID is the same. If it's not, it initiates a download from there. The update package itself is pretty big, but it might not add a lot to the final installation size of the game - usually they're just doing a 1-for-1 replacement of existing files with fixed code. Sort of like if you had a sofa in your house that took up a certain amount of space, and it was getting holes in it, and the company came and took the old sofa out and put a new one without holes in it > _ >",
"They have, on their server a little file called \"current version\". When you start the game, it connect to internet then check what is written in \"current version\". If it's the same, the game jsut start and don't ask anything else. If it's different, the game send the number of its own verstion, and the server decide, depending on how old is yours the files it needs to send."
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kczvyw | - How does a dishwasher save more water by being on for hours compared to hand washing dishes? | Technology | explainlikeimfive | {
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"It sprays the dishes with water for a minute or two and doesn't drain it. It then recycles that water to continue spraying the dishes over and over. It then uses fresh water to rinse them off. When people wash dishes by hand they often just leave the water running which winds up using more water.",
"A dishwasher just re-filters and throws around the same water for a long time. Since we're talking specifically about water usage, a relatively small amount of water recycled and sprayed around the dishwasher for an hour or two replaces all of the manual work that a human would do. Plus, the dishwasher only needs to flush and refill once (depending on your settings) for the wash and rinse cycles. Meanwhile, if you're anything like me, you sometimes empty and refill the sink for dishwashing a lot of greasy grubby pots and pans (that water can get _gross_, I don't want my hands in it). Dishwasher, like honey badger, don't give a shit - it just keeps flinging that water around until all the bits are scrubbed off. Since the comparative amount of water is so low compared to several sink-fulls, dishwasher wins. If you ALSO include the electricity use (forgetting energy use to heat the water), google says an Energy Star compliant dishwasher would use less than 1/2 kWh, so a few cents, less than a dollar. Now put a value to an hour of your time: $20/hr? $50? Dishwasher wins hands down.",
"Noone yet mentioned the time factor. The machine soaks all the dishes with a warm water spray, and sits for tens of minutes just letting it soak in and get soft. Usually when people wash dishes they do not sit around and let everything soak, and if they do they might fill a whole sink of hot water. Time, water, and heat all make it significantly easier to clean dishes over an hour long cycle, instead of a human trying to do it as quickly as possible. It all comes down to technique though too. I am a pro with handwashing dishes, I know I use a tiny amount of water because I save it all and feed it to my plants. \"According to a leading manufacturer, a standard dishwasher uses around **9.5 litres of water per wash**, while hand washing **generally uses up to 60 litres**.\" I use about 10-20 litres by hand. 9.5 is the lowest record setter for a machine. People who use 60 litres by hand are either careless or just bad at washing dishes with few resources.",
"A dishwasher does recycle the water it uses for cleaning. The bottom of the dishwasher is a sump of water similar to your sink. It is actually often smaller then your sink and holds less water. In the sump there is also a heating element and a pump which pumps the water from the sump and spray it on the dishes. The process is usually very similar to how you wash it by hand with a cold rinse then a main wash cycle with hot water and soap and then lastly rinsing off the soap and air drying the dishes. It will therefore fill up the sump three times which is similar to how you should wash dishes by hand. But when the dishwasher spends hours washing the dishes in economy mode it is not saving as much water but instead saves power. The main wash cycle should be done with high temperature water so that the dirt gets quickly dissolved into the water. However if you use colder water the same process will take place, especially with the soap, but it will take longer. So by running the main wash cycle at a lower temperature but spending more time the dishwasher will still clean your dishes but spend less power heating the water. Similarly when it is drying the dishes it can use the heating element to dry the dishes faster but on more economical settings it will often reduce the temperature during the drying process so it takes longer but saves power."
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kd8yuy | I replaced 50w halogen light bulbs with 7w LED. Whenever my oil boiler ignites, the LEDS dim A LOT for a second, a lot more than the halogens did. It really doesn't bother me, butwhy does a bulb that draws less watts dim more than one that draws more, with a sudden current draw? | Technology | explainlikeimfive | {
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"LEDs are very voltage sensitive, and it’s really non-linear. When your boiler starts up there’s a big current draw (either the igniter or the fan, probably), the voltage drops, and your LEDs fall way off their peak emission voltage. And they do it really quickly (LEDs respond nearly instantly). A halogen bulb responds much more slowly, so it can “bridge” the voltage transient better, and it doesn’t respond to voltage transients nearly as strongly.",
"The halogen bulbs have a filament in them that has to cool down below a certain temperature before they stop glowing. That doesn’t happen immediately. LEDs stop emitting the moment power stops. So basically the halogen filament buffers the drop in voltage and you never really noticed it.",
"It's probably ironically because those LED bulbs are not dimmable. LED emitters only work within a certain voltage range so when the power goes down just a bit they get very dim. Dimmable LED lights have special circuitry inside to handle the situation by storing power in a small capacitor then pulsing the light on and off at full power."
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kdaakv | How are animation movies (Pixar, etc.) made? | Technology | explainlikeimfive | {
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"The old style of animated movies was to hand paint the backgrounds, and overlay the characters on semi-transparent sheets. That would allow them to use the same background for many frames, and only have to change the characters. Toy Story (which came out in the 90's) was the first feature length movie to be entirely animated on computers. Toy Story uses 100% computer generated graphics. In the 90's and 2000's it wasn't unheard of for animated movies to blend techniques, doing some hand-drawn frames and some computer animation. Nowadays pretty much all animated movies and shows are done on computers, even the ones that look hand drawn.",
"The process of making CG animation is actually more akin to making a stop-motion/claymation film rather than traditional hand drawn animation. You create a model, rig it up with a little skeleton, build it an environment, detail the surface to make bits look like they're made of different materials, light it and pose the models. All of this is basically identical between CG and stop motion, only with the former being done on a computer. The major area where it differs is the actual animation itself. With stop motion (as well as hand drawn animation), each frame must be created individually and distinctly from each other. With CG, those little bones get animated from place to place, with the frames in between being filled in automatically by briefly describing the curve between them - IE the motion can be linear, or it can slow down as it approaches the next point etc. All of these different points can be on different frames for different bones. On top of this, you can add \"dynamic\" elements like hair or clothing that react based on the physics of the moving objects - a spin of the head wooshing a pony tail around our a tie flapping in the wind. Then finally you render the image, which is whether computers calculate all the lighting and reflections and the like. This is broadly equivalent to a stop motion artist photographing their organised frame before moving on to the next one."
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kdcr4e | What exactly is overclocking in PC's? | Technology | explainlikeimfive | {
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"Your CPU has a tiny clock built into it. It sends the instruction, electricity, and whatever into the circuits. Then uses the clock to waits a bit for everything to finish, then a little longer for it to cool off, before starting a new thing. Overclocking tells the CPU to wait less time. So you get more instruction done quicker. The reason the chip maker didn’t just do that in the first place is that the chip might get too hot and break. Some people just have paid more money to get stuff to cool the chip faster. If someone is dumb enough to tell the CPU to wait less time than the chip can finish an instruction, then even if their chip survives the heat, then it wills start doing things wrong, because it couldn’t finish in time before a new instruction arrives."
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kdkpds | If location determines the IP address, can users that are connected to the same network have the same IP address? | Technology | explainlikeimfive | {
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"Can users share the same up address? Yes and no. Each device needs its own local IP address. However there are local IP addresses on the inside of the network, and external (public) IP addresses which is what the outside world sees. So users while having their own local IP address, can share the same external public IP address. This is because usually the device facing the outside world (router or firewall) will have one or few IP address showing to the outside world.",
"> If location determines the IP address Bit of a false premise. Location doesn't determine anything, the network structure does. It is a good rule of thumb that if you assign an ISP branch in Bumfuck, Ohio a range of IP addresses to distribute to its customers, that such IP addresses would be in or near said town. Since such ISP level address range assignments are public record to help with accountability (who do I have to pester if somebody tried to hack my stuff from this address?), you can search IP addresses to about town accuracy (at most). It doesn't, however, mean that you can't pay to have your 70km fiber line plugged in at their office and assigned an IP, which would result in an IP address nominally geolocated to a town but actually belonging to a router waaaaay away from it. My IP address for example usually geolocates to the capital of Hungary 100km from me, because that's where my ISP's own network meshes with the \"public\" ones in the Budapest Internet Exchange.",
"Location doesn’t necessarily determine IP address, but yes, multiple people with local non-routable IP addresses going through a single router will appear to have the same external IP address. Example: Devices on your home network will all look externally as having the same IP address. Internally, they will all have different addresses.",
"Something to keep in mind, there are two different kinds of IP address. Internal and External. External is the address that gets used for any communication via the internet, internal gets used for any local traffic, like sharing files between PC's. Each device on your network has a internal IP address, while your router has the external IP. Two PCs on the same network cannot have the same Internal Address, but they can have the same external address since they use the same router. Any requests to webpages gets sent from your PC (local IP) to the router, router sends it to the webpage using the external IP address. Webpage responds to the external IP address, and the router sends it back to the original internal IP address. I am by no means a professional in the field, but thats the easiest way I can explain it. Found this avast article about it; [ URL_0 ]( URL_0 )"
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kdkum2 | Why do current websites' HTML code looks so confusing even though the page itself looks minimalistic? | Hi. Lately i have been inspect elementing websites to see how they are built, so i can learn more about how things are organized. Alot of times i see websites have alot of confusing divs and class names. Is this done in purpose so people don't steal from the page? How do you even do that? | Technology | explainlikeimfive | {
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"Two things here. First off, frameworks like Angular or Meteor \"transpile\" the code one writes into that weird and confusing HTML you're seeing. Other than that, there are minifiers/uglifiers, that try to either compress or obscurize the code being run. Also, pages like Instagram, use dinamically generated classes to prevent bots being made atop of them too easily.",
"Some weird comments here. Humans are still writing the HTML, but may be using frameworks that inject HTML ( written by humans), however this can create additional extra elements that if you were writing HTML completely by hand, you likely would not structure that way.",
"It is mostly accidental. Most developers and designers do not write the HTML code themselves but rely on a framework to write the code for them. And while this make it much easier to make websites it does not produce code that is easy for humans to read. The intention with the code is to make it much easier to work with in the CSS and JavaScript. It contains a lot of unnecisary div, class, ref and other things which make the code less readable but makes it much easier to generate CSS and JS to target individual elements or parts of the website.",
"There are two main reasons: 1) A lot of it is not written by a human being, but is either generated by some kind of website designing program or generated dynamically by a program running on the server. Those programs don't care about designing simple html, because no human is intended to read/edit it. The html tends to be complex because html can be very finicky, so to make sure things display correctly without a human manually checking and tweaking things, you have to use a very complex template, regardless of what the final layout looks like. For example: When you request to view a thread on Reddit, Reddit has to generate the html page for that thread by pulling information from a database, then inserting that information into a template. Since the template has to be able to fit whatever content/layout/etc that you have have, it has to be very complex. 2) A lot of that complexity is there to support dynamic content, such as adds, javascript, etc. Even if that content doesn't look very complex in the final layout, the process of generating it is complex.",
"HTML used to be written by humans and it was fairly easy to read. Now humans usually program robots and those robots write the HTML. The robots write HTML that is easy for other robots to read."
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kdps0s | Why can't every file be compressed to a simple mathmatic formula? | I know files in full binary format are massive, but couldn't it be expressed as a simple math problem? like, I dunno 10\^728+111 or something? I am not a programmer nor do I really know a lot about file compression, but it would make sense to me if this could be done we could compress massive files to incredibly small spaces. I am aware decompression would take significantly longer as the device would basically have to solve the math problem but that doesn't seem unfeasible. | Technology | explainlikeimfive | {
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"In theory, it can. In some obscure cases, the formula might end up being as big or bigger than the original file and you wouldn't have achieved anything practical, but in theory you can. The problem is finding the formula...you know the answer (the bit string of your file), you need to find a formula that generates that exact answer. Writing an algorithm that generates \\*a\\* formula with that answer in reasonable time is fairly trivial, but the formula will be huge (almost guaranteed to be bigger than the answer). To generate a \\*simple\\* formula, and in particular one much shorter than the answer, is not trivial and there's no guarantee that a smaller formula exists, so you'd have to exhaustively search all possible formulas (an infinite set). This means that you don't know how long your \"compression\" system will take to run, which is a bad property for an algorithm. Creating a relatively simpler formula of a known form is basically what modern lossless compression algorithms (.zip, etc.) do today. They're a good balance of speed, practicality, and size reduction.",
"Lets do an example: Your file is a picture, basically a list of coloured pixels. It could be all black. Then it's very easy to compress to \"=0\" and only the size of the picture is independant information. But every pixel could be a random colour, and then the amount of information is already minimized in the original form, it can't be compressed further. So all the numbers are indeed needed. What matters is basically the information content, the degrees of freedom that have been used. You can't encode something complex with fewer symbols without losing information. You can easily find out how much information something contains by asking \"how many different versions could exist?\". Because the code that represents something must be able to have enough variations to encode all of them.",
"Let's say we want to compress a giant 100-bit file into a tiny 20-bit formula. There are 1,048,576 possible 20-bit formulas. There are 1,267,650,600,228,229,401,496,703,205,376 possible 100-bit files. In order to successfully recover the original file, you have to find a unique formula for each possible file. There simply aren't enough shorter formulas to go around. (Regardless of the specifics of what kind of formula you pick, or how you represent it with bits, or how you get the formula from the input data.)"
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kdqa4o | Why are dodgy websites rigged to redirect you to arbitrary webpages depending on where you click? Are they just ads? Do the number of clicks benefit the website or its revenue somehow? | Technology | explainlikeimfive | {
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"So it depends. For legitimate ads then yes the website can be paid per click, so the more people it gets to click on the ads the more revenue it potentially makes. For non legitimate sites or dodgy sites they could be sending you even more dodgy websites where malware or other malicious code can be injected, for example key loggers, activity trackers etc. How does clicking on a link to a website give you a virus? Well there are several methods but one of the simplest is that each time you open a webpage it downloads some data to help it run. If it's a dodgy website then it can embeds malicious code in the portion that is downloaded. This is a simple answer to a complicated topic but hope it gives an overview."
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kdvl05 | What makes one hack/security breach "so sophisticated it could only have been a foreign government" vs one that isn't? | I'm not a programmer or anything, but it seems like this would be a difficult thing to determine. | Technology | explainlikeimfive | {
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"Hacking can take a lot of recourses. Custom software, reconnaissance on targets, sophisticated knowledge of very specific computer environments. Expensive password cracking rigs. Day 0 exploits if we are getting really fancy. It gets to a point where the cost and scale of what was done could only be done by highly competent professionals with vey expensive time and custom never seen before hacking software ('tools') that are very expensive and hard to develop, and cant be just found on the dark web, which would be already known as security vulnerabilities and scanned for by virus software etc etc. It gets to a point where no one individual could have done this, some massive well resourced and skilled team did this. Corporations sure cant because it is illegal. Only a huge well financed highly professional team shielded from prosecution which can only be state actors.",
"If the breach was someone brute-forcing a password, that takes an absurd amount of computing power. In some cases you might be able to say \"only China, Google, IBM, the NSA, Japan and possibly Russia have mainframes big enough to have done this\". Unspoken assumption: Google, IBM, the NSA and Japan are friendly and wouldn't have, so that takes the list down to two foreign governments - which they tactfully refrain from naming."
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kdvsz8 | How’s the method in which a game like GTA V with its Online and constant updates or Tesla’s software with its updates is developed and shipped called? Is this something like iterative or incremental development? | Technology | explainlikeimfive | {
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"There's a bunch of terms for the same basic idea. Incremental development is a good general term. \"Spiral development\" or \"spiral deployment\" is commonly used in defense contexts. \"Agile development\" is often used in a software context (or \"SAFe\" in some industries...Scaled Agile Framework for Enterprise). I'm pretty sure other industries have their own term for the same basic idea."
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kdxp9y | How do video game companies continuously fail to properly distribute their new console every time a new one launches? | Technology | explainlikeimfive | {
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"Because it's expensive to contract/build manufacturing capacity to immediately meet the initial surge of demand. Imagine building 20 factories to just make PS5s, then start closing them one per month over the next year because you've already met the demand. How much money would be wasted in the construction of those facilities/training of those workers, which is now useless because you're overproducing? They plan manufacturing capacity in order to meet long-term demand, not initial demand, because that initial demand is very short-lived. It's not worth investing in huge production capacity.",
"Because you can only make consoles at set rate--your factories can only assemble them so fast, the people who supply the chips/drives/etc can only provide them to you at certain rates, etc. So you get to the point where if there are 5 million people who want your console at launch but you only will have 1 million produced. At that point, do launch, sell the 1 million, and the rest get them as fast as you can produce new ones? Or do you delay the launch, rack up warehouse expenses for just storing them, and then nobody gets the console for several months until you produce 5 million?",
"It all comes down to how soon the company wants to turn a profit, or at least recoup their costs. Sure, they could sit on their hands, manufacture millions upon millions of consoles, and then release them in one huge wave. The problem with that is that it would take months upon months to manufacture all of those consoles, and during that time the ones already produced would just be sitting in a warehouse somewhere, gathering dust, not earning any money. And of course, you can't wait around forever, because if your competitor releases their console before you, they might just steal a bigger share of the market, and all of a sudden fewer people want to buy your console. Now you're sitting on a whole bunch of consoles that might *never* sell, and you're out a whole lot of money. So they try to walk a fine line: create a powerful console with modern components for the right price, manufacture enough to handle a portion of the early demand, and release at a time when the market conditions are right: preferably before the competition releases theirs, but at least around the same time. From a business point of view, it's better to produce fewer consoles and leave an increased command than to produce more consoles and risk missing a good window (like the holiday rush) or risk your competition snapping up more of the market share. The only downside would be people being so frustrated and unable to find, say, a Playstation that they buy an Xbox instead, if the supplies are better on one side or the other. But such is the risk. Of course, no plan survives first contact with the enemy, and COVID's increased precedence of online sales caused its own share of problems - especially scalpers and bots who manage to snap up large numbers of consoles, taking away from that limited supply. Those scalpers are working on their own supply/demand curve, though: once there's enough consoles on the market that most of the demand is met, there won't be people willing to spend $1,000+ on a new Playstation or Xbox. Now the scalpers have to lower their prices, and their investment of time and money might not prove as valuable."
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ke01w7 | How do front speakers emulate surround sound? | I have a 2 speaker + 1 subwoofer setup for my computer and it's really good. I can hear enemies coming at almost any direction, even behind me when I'm playing games. How do my two speakers in front of me make sounds that sound like they're coming from behind me? Is it some sort of auditory illusion? | Technology | explainlikeimfive | {
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"There is something called binaural audio (HRTF filtering) that creates auditory illusions by recreating the effect that the shape of your ears have on audio behind you etc to mimic uncanny localized sounds (there is a really good barbershop sound demo out there somewhere). But afaik that only works well with headsets. TLDR; no idea",
"I’m not going to act like I know a ton on the topic, but it is something I decided to read up on a couple weeks ago, so I’ll give it a shot: we have two ears, yet we *already* somehow can tell sound direction. How? The way the sound has to bend around our ear and travel in differently gives it **tiny** timing delays, and we’ve learned to interpret those delays as direction. Companies have begun to research and try to replicate those delays, making the sound just a fraction of a second earlier or later and emulating direction. The general field is “binaural audio” or “binaural recording”"
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ke217r | Why do TV screens and monitors look better than what I see in person? It's as if they're "clearer" than my vision. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"TV screens are lit. You may be losing low light vision. Many things can cause this like glaucoma, cataracts, shedding from UV damage.",
"There are probably more than a few factors at play, to a greater or lesser degree, and all mixed together: 1 - When you're looking at a screen the screen is the focal plane. Even if the screen might be displaying something that is in close focus with a blurred background (like a closeup shot of an actors face or such) in the physical world outside of the film you're watching, you're only focusing on the surface of the television a few feet away. 2 - The image is backlit. Real life has messy and uneven lighting. I'm in my office right now, after dark, with various lights on... and the \"crispness\" of the room is a mess in that regard. Some areas are bright, some are dim, and other than the computer monitor I'm looking at right now none of them are projecting light *out* at me. It gives the monitor and the images on it a sort of hyper-reality compared to the duller surfaces in the room. 3 - The images you see on a television are, especially in the case of modern content, fairly stylized. The film/TV industry employs armies of people whose entire career is centered around tweaking and tinkering with the image you see on the screen to create the desired effect the director wants. Color grading, sharpening, etc. It's the same thing that happens when you see a really good landscape photo of somewhere you've been and the photo looks *so good* compared to what you saw. The photo is capturing a moment in time and that moment has been manipulated and tweaked to create a desired outcome. In that regard, even a simple sequence of a guy walking down the street in an action movie (before the action even starts) looks so much more \"real\" than seeing somebody walking by your apartment on the street because the whole experience has been carefully tweaked and calibrated to make you feel that way. 4 - Related to photography and lenses... the gear used in professional film making is phenomenal and can \"see\" things in a different way than you do in your day to day life because of focal length, lens \"sharpness\", etc. In a scene in a movie where the camera pans over a desktop, showing some crumbled paper, a broken pencil, and a tipped over glass, for instance, the angle and the clarity of the shot may be quite different (in terms of height compared to the way you'd look at in person and lens angle/depth of field, compared to your eye) than how you would actually see the scene in real life. Again, it's how that photo of a place you've been in person can look so different. So really I think it comes down to a combination of the tool and techniques used on the production side combined with the quality and brightness of modern TV and monitor displays."
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ke4qns | How is Siri able to red out any word? | Does the person narrating Siri sit and read/record every word in the dictionary? What's the logistic behind this? edit: ahhh wish we can edit titles, i meant read\* not red! | Technology | explainlikeimfive | {
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"No they mostly record the very commonly used words, and then add syllables to construct longer more rare words and names.",
"Well there are a limited number of sounds in the english language so instead of recording every word they just had her record many phrases with many different sounds in them. Then the programmers can cut up the sounds and make any words they want. Here's a quote from Susan Bennet, the default Siri voice: *\"We recorded hundreds of phrases and sentences that were created to get all the sound combinations in the English language. Now, the English language has over a million words, so you can imagine how long this took. The initial recordings took a month in 2005 \\[before the iPhone even existed\\], four hours a day, five days a week, then I did updates for four months in 2011/12.\"* From this article: [ URL_0 ]( URL_0 )"
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ke5btx | What is Github? | Technology | explainlikeimfive | {
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"text": [
"You basically got it. It's a community for people to produce code and leave reviews and receive advice from people who use it.",
"Github is an online place which handles *version control* of code. Version control means you can manage files, check differences between two revisions, step off the main \"line of development\" to build something (a fix, or a new feature) and then, when the time comes, merge (or, more frequently, ask someone to review and merge) that \"branch\" you created into the main line of development. You can also create a local \"repository\" (version-controlled directory) in your own PC, work locally and then sync a remote \"repository\" with your work, or viceversa (sync a local repo with updates made remotely). This is very useful for code, especially when developed by teams (although version control is now a standard used even by individual developers on their own), but potentially not just that (e.g. text documents can be written collaboratively by teams using some kind of source code version control system). Specifically, Github is an online platform (by Microsoft) following the Git version control system. On Github, you can create (remote) repositories, store your code, and use the features of version control. There are several version control systems, but Git is by far the most popular nowadays. Some of the basic operations supported by Git are: - Clone, to clone locally the content of a remote repository at a specific time - Add, to have Git consider a changed file as a potential file to be updated in the repository - Commit, to actually update the repository with your last changes (the ones you used the \"add\" command for) - Push, to push a commit in a local repository to a remote repository (e.g. on Github) - Pull, to update a local repository with changes made remotely (e.g. on Github) - Branch, to create a new \"branch\" off the main development line and work there for fixes/new feature without impacting the \"main\" (or master) branch - Merge, to merge a particular \"branch\" to the \"main branch\". Typically, while team working, everybody can work on their own branch, but only few people can work on the \"main branch\". Therefore, almost no one can merge directly. What happens is that a developer asks someone else to review their changes and merge that particular branch to the \"main branch\"."
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ke5fik | In a time where manufacturing took way more time than it does now, why were antiques so opulent and detailed? | Simple things like scissors made to look like a bird’s beak, embroidered everything, scrolling details on metal spoons and clawed feet on furniture... tiny buttons, fancy thimbles! Why so many details for every little thing? Might be a silly question, sorry. | Technology | explainlikeimfive | {
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"I imagine there were more cheap or plain items than fancy ones made, they just weren't held on to. Only the fancy ones were seen as worth preserving as antiques.",
"Because that kind of objects weren't so popular, they were typically owned by nobles or at least rich people. Since the demand was not so high, and those people had enough money and authority, artisans working on that stuff were really trying to do their best. Also, artisans' skills were probably measured on those kind of tiny details. It's not easy to embroid small things, and you still require proper artistic skills to actually \"draw\" a bird or a fancy shape. The reasoning was probably \"anybody can make a plain white button, but only some really good artisans can make buttons with your coat arms and maybe even some writings in Latin\".",
"It’s a good question. But the answer lies somewhere between the fact that modern fashion tends to be more minimalist and that back then people put more time and therefore, love into whatever they were crafting. It’s perhaps a chicken and egg thing here. I would say the latter is more accurate an answer and that our minimalist styles perhaps were born from mass production. I think if I were hand-making a button or a spoon and it had taken a lot of my time and attention I’d perhaps want it to stand out a bit. I think the fact that antiques are unique and detailed reflects the love that was put into it and it’s no surprise that antiques are so sought after in the modern day - in a similar way people want to be different in a world that is unfortunately driving us towards uniformity and dullness. As a quick example, long ago there would be millions of shops making spoons, now I imagine most will come from a handful of companies like IKEA and be distributed by Amazon. I think much like a lot of other things, manufactured goods are suffering an identity crisis.",
"There is an element of survivorship bias: the old objects that are still around are mostly the nice ones. Also in the past there were very wide wealth disparities between the small number of rich people and the large number of poor people. As a result the wages of workers and artisans were very low compared to the price that the rich consumers could afford to pay. This means that a lot of hours could be put into each object without it becoming cost prohibitive.",
"Yeah I think people have covered this pretty well but to sum up, it's a combination of a few factors. 1. Survivorship. Only good/unique antique items are worth keeping around. 2. People did take more time making items back in the day. While automation and industrial manufacturing have been around for a long time, there were things that just couldn't be manufactured by anything other than hand crafting until computers came around. Also before WW1 people just didn't buy as much so items were generally more expensive but better quality. 3. The style has changed. More decadent designs are viewed as tacky. Too many frills and suddenly that looks like grandmas couch. Modern designs tend to be focused around ergonomic, sleek, and minimalist designs.",
"A lot of those things were just the fashion of the times. All antiques aren't necessarily fancier than their modern equivalents. It just depends on what was popular then."
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ke6mte | I've read that a newer CPUs can be much faster than an older CPU even if both have the same amount of cores and the same clock speed. It says that newer CPUs can do certain tasks faster. How is that possible with the same architecture? | Technology | explainlikeimfive | {
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"There are multiple things that can affect the performance of a CPU: **Number of cycles per instruction** - A CPU executes instructions at a low level. There are for example instructions to add two numbers, or to multiply them. Where an old CPU might for example take two cycles to multiply, a newer CPU might only taken one. This effectively doubles the speed of multiplication without increasing clock speed. **Speculative execution** - When the CPU executes an instruction, it might need to wait for a component to respond. For example when you read from RAM memory, RAM memory chips have their own speeds. While older CPUs just waited for the RAM to respond, newer CPUs perform speculative execution of the instructions after the read, where possible. This way it doesn't have to wait for the RAM, and is thus faster without increasing clock speed."
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ke705c | How do they sort the garbage at the dump? | Every garbage day, I try to separate my recyclables (cardboard boxes, paper, packaging etc) and plastics from general waste like kitchen and food trash, but people tell me it’s useless because “they do that at the dump.” What is the actual process of sorting out different kinds of waste? And how to they separate them for decomposing? P.S. sorry if I used the wrong flair! Not sure which one to use. | Technology | explainlikeimfive | {
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"My dad retired from a major city's refuse union...sad to say that many if not most \"recyclables\" end up in the incinerator or landfill. Recycling is bullshit. It's way past time for policy makers to demand a better alternative to plastic packaging but they won't because it would be really hard to get re-elected without mega Corp donations..."
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ke8jfq | NASA has a telescope that can see the creation of stars and planets billions of years ago, how? Link is in description | Technology | explainlikeimfive | {
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"Light takes a very long time to reach us from very far away in deep space. The events that this telescope will show us will have happened billions of years ago but the light to let us see them is only just getting here because they happened billions of light years away.",
"A common misconception is that when we see something, we think it happened right then and there, but this is not the case. It's more clear with sound, if you have a friend stand let's say 100 meters away and claps their hands, you will see a noticebal delay between you seeing them clap and hearing it. This is because the sound waves takes time to travel to you. This is equally true for the light you saw showing them clapping! Light is also a wave like sound and moves at a constant speed. If a star \"claps\" and you stand 1 light year away. It will take exactly 1 year until you hear it. In this case the clap can be a burst of light, and you hearing it is you seeing/detecting the light. Because of the huge distances that is the universe, we can see old light from stars. Painting us a picture of how they looked like billions of years ago. These stars might still be alive or be dead when the light reaches us, but we will always see it as it was a long time ago. We can take another closer example, it is widly said that the light from the sun takes 8 min to reach us and this is true. If you look at the sun you will see a 8 min old picture of it!"
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