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6kesx9 | Why do so many old songs have instruments/vocals that sound only through one ear? | Sorry if the question is weirdly formulated... I couldn't come up with a better way to describe it. When I'm at work, I only use one earphone when listening to music, so I can still hear if anyone asks me a question. However, when listening to older songs, I often have the problem of missing most of the song because some instruments or vocals only sound through the earphone I'm not using. Is this difference in recording a choice by previos groups to add something special to their songs? Or was this a result of the technology avalable for recording in earlier years? | Technology | explainlikeimfive | {
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"Stereo was invented (or came into common usage) in the 60s and, whenever something new is invented, we like to experiment with it. This, plus all the psychadelic vibe in the 60s, resulted in some very bizarre combos. Over the years, we've perfected the art to something more balanced (or dull, depends on your opinion). Now we put vocals, bass and most of a drumkit down the centre (equal volumes on both sides), though some things still take up the left and right channels. Some things will be similar and panned apart - eg two backing vocal tracks, drum kit overheads or two guitars playing exactly or almost exactly the same thing. The idea now is that there should be an evenly balanced mix of bassiness, trebliness, rhythm etc across the spectrum. Although I love crazy panning, I don'tl miss listening to just a tambourine and a piano part when one earphone broke, though it was interesting. Edit: typo"
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6kfabs | How do Reddit bots like the "autotldr" bot work? How can it summarize a news article? | Technology | explainlikeimfive | {
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"The bot's comments have a FAQ which should answer your question. It rates the importance of sentences based on the frequency of words used."
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6kfpfa | How do 3D games work? | How does a 3D game like GTA work, where the player moves in all 3 planes? Is the world developed just a 3D array, where the player and other AI objects are vectors that move through that array? How does AI behaviour and physics get computed? Also does the game work by reading the users input, calculate how that input alters the world, AI behaviour, physics, and then renders a frame? And it does this 30-60 times per second? | Technology | explainlikeimfive | {
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"Former game developer here, 3D games are typically polygonal. A polygon is a triangle in 3D space. This requires 3 points in 3D space. A point has an X, Y, and Z component, a coordinate for each axis. So that's 3 sets of 3, or 9 coordinates for one polygon. Each coordinate is stored in 32bits/4bytes. So a single polygon requires: 4 bytes per coordinate * 3 components coordinates per point * 3 points per polygon = 36 bytes per polygon. Models in video games today can have many tens of thousands of polygons. In order to cut down on memory usage, we try to reuse points as much as possible. Each polygon is typically going to share each edge with another polygon, so we can compute a minimum set of points in a model, store that in an array, and have another array of 3 indexes into the point array to describe each polygon. Each index is also 4 bytes, so that's an additional 12 bytes per polygon, but the memory savings from removing duplicates wins out as soon as you have 2 polygons sharing an edge in a single model. Triangles have a neat property; you specify them in terms of 3 points, and the order of those points will go either clockwise or counter-clockwise. This is called the right-hand or left-hand rule, because if you hold up your left hand and point your thumb toward yourself, you'll see your fingers curl clockwise, and the opposite is true of your right hand. So what can we do with that? Well, models have a front and a back, yeah? If you're looking at the front, you can't *see* the back, can you? Well, if *all* your polygons *obey one of the handed rules*, then what happens when you're looking at one side of the polygon vs the other side? Flip it over in your mind, and you'll notice that while the order of the polygons remains constant, the handedness flips! That's useful, because now we can consider a polygon having a front vs. a back. If you're facing the back side of a polygon, you don't need to render it, because it's on the back side of the model. That's that much more data you *don't* have to send down the render pipeline, saving cycles so you can do more of something else. This is called \"back-face culling\". Don't do work you don't have to. With an array of points and an array of indices specifying polygons, you can make a model. Oh! Here's another nifty trick! Since we can assume models share edges, you can cut down on the number of indices needed to describe your polygons by reusing the last two indices. Let me illustrate - if we were to naively list polygons in our index array, it would look like this: a, b, c, b, c, d... But notice we have a repeat in the sequence, we said \"b, c\", and then immediately followed that with yet another \"b, c\". Why don't we just assume the last two indices begin the next polygon? Then our data looks like this: a, b, c, d And we can assume the first polygon is \"a, b, c\", and the second is \"b, c, d\". You can specify whole sequences and \"fans\" like this. Modeling software relies on some very heavyweight algorithms to try to compute the longest and most compact sequences like this. The more memory we can save, the more bandwidth in the rendering pipeline we can save, the less and faster we can compute our rendering, the more rendering we can do! You'll notice that every other triangle inverts it's handedness, and the code has to take that into account regarding back-face culling. So your model is a sequence of points in 3D space. This space is called \"model space\". Now you need to move it into \"world space\". For that we use a matrix. A matrix describes the shape and relationship between the xy, xz, and yz 2D planes of 3D space. A point or a vector in 3D space consists of the X, Y, and Z components. A matrix consists of the X, Y, and Z component *vectors*. This makes a matrix a 3x3 square grid of numbers, and you can label the rows and columns X, Y, and Z. Typically you start with the identity matrix: x,y,z x[1,0,0] y[0,1,0] z[0,0,1] And this says all 3 planes are at right angles to one another. Each model gets it's own matrix describing it's own \"space\". Each space, then, is it's own coordinate space, or can be thought of as it's own universe, and what we want to do is describe how each space relates to one another. We then need an additional coordinate, W, that describes how one 3D space is positioned relative to another. x,y,z,w x[1,0,0,0] y[0,1,0,0] z[0,0,1,0] w[0,0,0,1] These are origin matrices, and they all say they're the center of their own universes. You would put values in the x, y, and z, components of the W column to say how that matrix is translated relative to another. The 3x3 XYZ components can get some trigonometry going on to describe how the space is rotated relative to another. Each instance of a model has it's own world space matrix. A neat property of matrices is they can be multiplied. So you start with one matrix, the origin, the center of the world, and you multiply by a matrix that says \"translate out to that direction\", then you can have another matrix that says \"turn to face that way\", and then another matrix that says \"translate to some other position relative to your current position and orientation\". I'm trying to illustrate this and I know it's kind of hard to follow without actually getting into the math, but perhaps think of each matrix as a waypoint, and you're going to take a one matrix and multiply it by waypoints to get to it's final destination. Objects in video games are often stored as hierarchies, so your guy is going to start at the origin of the world space, and move and rotate to, say, a whole map segment, then move relative to the center of the map segment to a house, then move relative to a house to a room, then relative to a room to a place in the room. In the end, the unit is standing in the room facing a particular direction. The final matrix is a perspective matrix, and it's considered the camera matrix. Maybe you thought it was weird that I was saying matrices describe the 3 planes of 3D space relative to each other. Well, now we're going to fold space in on itself! You can skew the shape and orientation of these planes so that you bend the universe into a perspective view - where things closer are larger and things further away are smaller, and everything converges to a point on the horizon. This matrix also collapses the Z axis to make the universe look flat, so 3D objects are *\"projected\"* onto the 2D plane of your monitor. This has to be described mathematically, and here it is. So you have this camera matrix, and the whole world gets multiplied against it. Surprise! The camera is actually the center of the universe, and the whole universe gets shifted around by it, squeezed to a pinch in the distance, and smashed flat. THEN all the models get each of their polygon points multiplied by the camera matrix, and this generates 2D triangle coordinates that map relative to pixel coordinates on your screen. I'm trying, here... That's how triangles go from a conceptual set of points to coordinates onto the screen. Then algorithms use those coordinates to fill in the polygons along those edges and inside. But wait! There's more! There is ANOTHER coordinate system, called the UV (think like XYZ) coordinate system, that maps texture coordinates to model coordinates. I haven't written code like this for a long time, but each point in the model gets a corresponding UV coordinate that maps that point to a point on the texture. Then some matrix math translates that point on the texture to a point on the screen, and algorithms copy and paste texture data into the screen buffer. Some interpolation may happen to account for stretching the model like a skin, and to account for perspective. But wait! There's more! Normal vectors don't indicate a point, they indicate a direction. You can either have one associated with the face of a polygon, or, more useful and detailed today, one for every point on a polygon, or even per point per polygon, that means each polygon will have 3 normal vectors. These are used for all sorts of \"lighting equations\" that will modify per pixel light intensity and other visual effects. But wait! God damn we aren't done yet! You can have individual vectors per pixel! These are used for more elaborate light equations, the result is that texture images, when put on a model, look like they actually have 3D texture, like pitting on a rusty panel or rock texture. These are all just light effects. If you've ever looked at texture files, they're just BMP files, and they come in sets, one might look like the texture but is very purplish. This is actually 3D normal vector data, it's just a very convenient way to store it, and it translates by coincidence into image data that happens to look neat. So, every frame being rendered requires multiplying a hierarchy of matrices from model space down to their world space, and then to camera space, then all the points of any given model is multiplied by their camera space matrices, one per instance of that model, and that data is used to map color data from textures and light equations onto screen pixels. If you want to learn the math, it's called Linear Algebra, and it's actually *very easy*. There's the pure abstract concept of LA and solving linear equations, but you can honestly ignore most of the theory if you just learn how to multiply vectors and matrices, and study the subject under the focus of just video games. At the very least, it will help you appreciate the general process of what's going on here. Yes, of course it pays to learn the subject in depth, but god damn it people, don't be so pedantic, some people just want or need enough to get by. Not everyone is going to become a mathematician or game developer, they just want to \"get it\"! Let me know if you want me to comment further about other aspects."
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6kfyya | Do breathalyzers measure BAC accurately for people with lung issues such as asthma, COPD, or just being generally out of shape? | Technology | explainlikeimfive | {
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"Breathalyzers are \"good estimates\", not highly accurate. They don't measure total breath flow, either. They just determine the percentage of alcohol in the C02 of your breath, and conditions like asthma, COPD, or others don't really have any affect on that. If you're on the verge of blowing just at the legal limit, you can contest the findings of a breathalyzer test by providing urinalysis, which is highly accurate. They can then work backwards using simple math to find your BAC at any given point in time."
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6khrql | Why is electronic recycling so difficult? | Technology | explainlikeimfive | {
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"They are shredded and then pass through several separation steps. First, steel is extracted via magnets. Then an eddy current separator moves aluminum, copper and other non-magnetic conductors from the plastic stream. They can even separate ABS plastic from polystyrene. A small fraction of the shredded pieces will end up being non-recycleable and go to a landfill. Edit: [recycling video]( URL_0 )"
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6kiaay | How have phone operating systems, today managed to reduce the time required to uninstall an app within a second, irrespective of its size(Android OS) | Technology | explainlikeimfive | {
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"I can't destroy a building you're using in a second, but I can lock the main door in a second. The result will be the same for you, you can't use the building anymore. I'll then take my time to actually destroy it properly. Your phone doesn't completely delete all the stuff in a second. It is just deletes the icon that launches it, then it can take its time to actually delete all the data. Also, deleting a 200Mb app doesn't mean actually doing something with all the 200Mb of actual switches in your memory. It just tells the phone that it can write something else on that part of the memory, which makes even the deleting process in background faster."
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6kjxvc | With all of the advances in technology, why does it still take a few moments for tvs and set-top-boxes to change channels? | Technology | explainlikeimfive | {
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"Television signals contain a lot of data in a compressed format. Your state of the art TV needs to find the signal, buffer the data and then send it to your screen. In areas where there is a lot of interference, sometimes the signal you are receiving is degraded and additional buffering needs to happen to allow a continuous flow of images. Unlike analog which would simply send the signal it had, with static from a degraded signal, digital TV's need more information to construct their images, and incomplete signals are pixilated and the audio often skips as well."
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6kknx6 | Why can’t computers directly link parts for faster data speeds? | For example, link your network card to your storage media (without the data ever crossing the CPU or other parts) for a lower-latency download. | Technology | explainlikeimfive | {
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"There's really not much bottle neck to writing to storage, because that's about the slowest thing that can happen on any computer. Really the latency isn't due to the connections and architecture, but the fact that storage devices are slow. The peripherals do have direct access to system memory however (over DMA) and the processor can initiate transfers without the data ever being held in cache or registers on the processor, it just gets buffered in memory. It then has to wait there while the storage device is being written to by a memory controller, which is way slower than data being written to system memory. Something else to be aware of is that the OS is like a maestro directing an orchestra. The players can keep on doing their thing independently, but someone has to hold it all together and make sure everything is in time or else the music turns into noise. So there will have to be some kind of connection to a central controller, or else you don't have a working machine. Edit: not to mention security and safety issues. You don't want a peripheral accessing storage without the OS being aware or without protections in case something is amiss. Otherwise your network card could write malicious bytes to storage without the OS ever knowing about it."
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6kkxak | Why do Canadian websites end in .ca and U.K. Websites end in .UK but United States websites don't end in .us? | Technology | explainlikeimfive | {
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"Basically because the US created the internet and the US government controlled all the non-country specific Top Level Domans (TLDs) in the early days (.com, .net, .org, etc). Some of them are still controlled by the US only like .mil and .gov. Countries had more control over their specific TLDs like .ca and .uk, so were more easily able to give them to businesses in their country. However the US had more strict rules for getting .us in the beginning while .com and .org had fewer restrictions. So the US got used to not using .us even though it is available (and more open) today.",
"There is a .us domain but hardly anyone uses it. As far as .com, .org and .net they are not restricted to the US, they are available internationally.",
"Those endings are relatively recent. The US web sites use the older .com (commercial), .org (organization), .gov (government), .edu (education), and .net as their suffixes. This is because the US invented the internet and so has a lot of control/influence on it.",
"Various reasons. A major one is that for a long time, the .us domain was highly restrictive. You couldn't have \" URL_0 \", or even \" URL_3 \", but it had to be \" URL_1 \". Naturally online businesses didn't want to be associated with a single city or county. They also wanted a short snappy domain. And plenty of companies were going with \".com\". The \".com\" domain became synonymous with the internet. Canadian companies were perfectly happy to use URL_2 , especially if they wanted to market mainly to domestic customers, because the domain makes it clear that it's Canadian. The uk insisted on third level until recently, but since they differentiated between organisation type (. URL_4 ) and were quite short, this wasn't seen as a problem.",
"The .us TLD exists but is not used as much. Since the internet stated out in the US the non-country specific TLDs like **.com** and **.org** became established as a standard before the **.us** had a chance to catch on. Some countries mix the two so that for example the **.com** for the UK ends up being **. URL_2 ** while others just put everything directly under their country tld, so you have **amazon. URL_2 ** and ** URL_1 ** in the UK and Japan but ** URL_4 ** and ** URL_0 ** in France and Germany."
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6km800 | How do space agencies keep up with new technologies in their projects/missions? | Hello! Today I came across with [this tweet]( URL_0 ) and the second photo is mission timeline of various mission. So, as you can see, planning phases and mission duration covers huge amounts of time periods and I was wondering how do space agencies (spacecraft companies and researches in similar areas as well) keep up with new technologies in their projects, mission, researchers etc.? Do they stick to the plan, or implement new tech without causing themselves to miss the deadline? Edit: Thanks you all for your responses! I appreciated a lot for taking your time. | Technology | explainlikeimfive | {
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"They don't keep up with it. All tech launched into space is fairly old. When they design the craft most of the tech isn't cutting edge, then it takes several years to build it, then a couple years of testing before launch, and by the time it's launched it's old Keeping up with new technology in an active project is rarely a good idea, feature creep is often your worst enemy and will keep you from shipping anything *ever* because there's always something new. You have to nail down the specs, write them in stone, and run with it.",
"Unless an advancement is revolutionary, or if it solves a critical problem that was not known before, its generally not worth it to change anything. Once you have equipment that will function, space missions are actually (relatively) simple, and don't require the most modern technologies."
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6kma8m | Why you can put in the recycling bin same files with the same name but you cannot do that in any other folder ? | Technology | explainlikeimfive | {
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"The recycling bin is a \"virtual\" folder that shows a list of deleted files that can be undeleted. Deleted files aren't actually *moved* in to a different folder: they stay where they were, they're just *marked* as deleted. The recycling bin is a \"view\" that lets you see all the deleted files in one place.",
"On the Windows operating system, the files are all moved into the one Recycle Bin folder, but are first renamed with a unique incrementing number. The original name of the file is stored in a special hidden file called \"INFO2\". When you view the Recycle Bin, it does not show you the actual recycle-bin's folder structure, but uses a specialized control to display the INFO2 contents like a folder. See URL_1 for a bit about the Recycle Bin, and URL_0 which shows the contents of an INFO2 file."
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6kmb6t | What is P2P network? I know it has already been answered here but I still don't get some basic things. Details below. | **What is P2P network or Peer-to-Peer network?** I found this in one answer on reddit -- > Scenario: a needs to talk to c, using service provided by b. client server: a talks to b, b talks to c, c talks to b, b talks to a, and so on. p2p, a and c connect to b, b tells a and c how to talk to each other, b is not needed anymore, a talks to c whenever needed. Is it correct? There is no "middle server" between two clients? So, let's assume that, I am talking to some friend in Washington DC from California. First, my data goes through a series of routers to a server of that chat application, that knows the ip address of my friend and knows how to divert my data there. The server then sends my data through a series of routers to my friend. The same thing happens when my friend replies back. **This is server-to-client network, right?** But, if it were P2P network, my friend's PC would know my ip address, and would send the data itself directly to my PC without the need of any server itself. So, there would be no intervention or control over this chat exchange from any server. **The data would start from my friend's PC, flow through a series of routers, and reach my PC in a P2P network, right?** **My question is, how my PC or my friend's PC would know, what path to travel, where is the destination or what routers to choose along the journey to reach the destination, if absolutely no server is involved in the process?** I know the question is long, but I can't get over this very basic thing. Thanks for reading. | Technology | explainlikeimfive | {
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"What you're asking for is called [IP routing]( URL_0 ) and is one of the fundamental structure of the internet as we know it today. The basics of it is everything with an ethernet or WiFi adapter keeps a routing table which tells them if I want to access X address, send the packet to Y because he know how to get to X. In case they don't know, they have a default address to send it to and this address will do the same process. To take your example, you PC never know where your friend is, but it knows someone that knows someone that know where your friend is."
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6kmoix | At what point does a program/software qualify to be called an AI? | Technology | explainlikeimfive | {
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"The problem is that we don't have a formal definition of what AI is, therefore different people have different requirements for calling something AI. It's a bit like asking \"at what point is a movie good\"? On one end of the spectrum we have people (i.e. the media) calling everything AI. Walmart's data warehouse software spit out a statistical correlation that says men buy belts when they buy pants, so it makes sense to put belts next to the pants rather than on a separate \"men's accessories aisle\". Walmart makes a billion more dollars that year and people congratulate the AI, because obviously the computer looked through the data and came up with independent conclusions that people thus far hadn't reached. Somewhere closer to \"true AI\" we have expert systems. So a program has a better accuracy of diagnosing most medical conditions than your average GP. Is that true AI? If a self-driving car reacts faster and has fewer accidents on average than human drivers, is that AI? And so you can have more and more requirements to specify what AI is. Maybe it needs to do X better than humans. Maybe it needs to learn completely unassisted (like just open Wikipedia and go from there), etc, etc. In the far end of the spectrum you have people who if faced with an \"AI\" that does everything a human mind does will tell you that it's not true AI, because it just mimics human intelligence.",
"I went to conference where one of the developers of the game Alien: Isolation was speaking. He said that to satisfy the marketing promises, they had to have some sort of AI. So they put in that if you attack the alien with a flame thrower, it won't approach you head-on again if you have a flame thrower out. That was literally it. AI is a big marketing buzzword right now. There are genuine attempts to develop a true AI but they are few and far between. Most of the rest are just a way of changing the behaviour of a system in a set way depending upon specific variables, not real learning or adaptation.",
"AI is a really broad term, but usually it means that a piece of software can make decisions for you. A example of a decision might be to mark a file as likely to be malware or not. Its possible to have a list of all malware ever found and compare the files one by one to see if you get a match, and then alert you, but what's actually happening, is that the software has a more general set of 'rules' that it uses to look through any given file, and then decides to flag your new file as malware or not depending on those rules. Later, it can submit your file for more exact analysis, but if it did that for every file, scanning your computer would take *forever*. Also, those rules are ever changing (as the developers get more examples of real malware to use as examples for the program to develop more precise 'rules' from) this is machine-learning, broadly. And, at a very elementary level, that's how human intelligence works, you make better decisions as you get more information about a subject. So we call them artificial intelligences."
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6knhfx | I remember gifs being horribly low quality just a few years ago, but now we have super high quality ones. Image quality didn't really get better, so what happened? | Technology | explainlikeimfive | {
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"Most sites started switching to HTML5 video elements instead of using conventional GIFs. GIF is an ancient standard in computing. It was first introduced in 1987 and the most recent update to the standard was in 1989 (28 years ago). A key advantage of the GIF standard is that it is widely compatible and supported across almost all mobile and desktop computing platforms. It's a standard that has been supported and virtually unchanged since the early days of personal computing before people even had internet access in their homes. The other advantage of the GIF standard is that it supports all sorts of useful features: 1. It supports animation, including the ability to control the timing between individual frames 2. It supports transparency (you can select a certain pixel color to be transparent so it allows content behind the GIF to show through the GIF). 3. Compared to some other image formats, GIF is often pretty decent at compressing the file size to reduce bandwidth and storage requirements. 3. It provides lossless quality (but not necessarily lossless color). * The GIF standard is limited to a 256 color palette (although you can create your own custom palette where you choose exactly what colors to include). That means that if your image requires 256 or fewer colors, it can be reproduced perfectly in GIF form with absolutely no loss in detail, resolution, or color. This makes it perfectly suitable for images containing text or simple graphics (but not as useful for photos or complex images with shading or gradients). So the reason why many GIFs appear to have poor quality is often they are being used to try and reproduce images/videos that originally contained more than 256 colors. Since the color palette in the GIF standard is limited to 256 colors, GIFs may appear to have relatively poor quality with respect to color reproduction. It is worth mentioning that it is possible to specify a different color palette for individual frames in a GIF animation. So while a given frame will always be limited to 256 colors, you can theoretically have custom palettes of a unique set of 256 colors for each individual frame. This can enhance the appearance / quality of the GIF by allowing for more accurate color reproduction, especially in animations that feature significant changes in lighting or color between frames. Nowadays, however, the HTML5 video standard offers a better way to embed GIF-like loops/animations into webpages. That's because not only are modern video codecs (like H.264) very efficient at conserving bandwidth/storage, they also support the full spectrum of color (or at least millions of colors). The HTML5 video standard and associated video codecs are also optimized to allow the web browser to download/stream the video data in chunks rather than having to wait for the whole file to download first (as is often the case with traditional GIF files)."
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6koarp | How did they do music videos Like "Take on me" without computers | Cant imagine how. Blame me for not knowing if its common knowledge but im curious. | Technology | explainlikeimfive | {
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"First they shot the entire video live-action, then used frames from the parts they wanted to be animated as the basis to trace out sketch drawings, then replaced some of the live-action frames with the animated frames. Where the two were meant to interact, they would superimpose the animation over part of the live-action frame. The technique is called [Rotoscoping]( URL_0 ).",
"Essentially what /u/KubrickIsMyCopilot said. Graphic Design and animated video production used to be an extremely labor intensive process. That is why \"Photoshop\" was such a revolutionary tool when it came out. It changed the industry immeasurably. Eventually that led to things like \"After Effects\", which among some others, is what everyone uses today to do Rotoscoping. All of the early tools in programs like these were based on manual processes people used to do. For instance [Dodging and Burning]( URL_1 ), which is used to lighten or darken parts of your photos, used to be done with [cut pieces of paper]( URL_0 ), your hand, or something else, while you exposed your ~~film~~ photo paper to light."
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"https://en.wikipedia.org/wiki/Rotoscoping"
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"http://scrapgirls.com/wp-content/uploads/2016/01/DodgeBurn_TGU_ss1-Panel.jpg"
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6kodqu | How can headphones deliver decent amounts of bass when normal speakers usually require a large subwoofer to produce the same effect? | Technology | explainlikeimfive | {
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"djnju30",
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"text": [
"\"Normal speakers\" are trying to make sound in a room that's many times larger than the tiny space in your ear canal where earbuds are making sound (or the small space inside the headphones where they are making the sound). Bigger spaces take more energy for the sound to be perceived as at the same \"level\".",
"The term \"decent\" is relative. Bass sound is interesting because we both hear it (with our ears) and in lower frequencies (at enough sound pressure) we *feel* it with our bodies as a whole. For our ears to detect sound, the ear drum needs to move. A loudspeaker is usually a long way away with a lot of air between in and your ear, so it needs a lot of power to move your eardrum. With headphones, there is only a few centimetres distance... and so a much smaller driver is all that is needed. What is missing though, is the large amount of moving air felt by your body...which is why immersive bass is best with large, well-powered subwoofers."
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6kp0ti | Why cant we send all of our pollution to the sun? | Technology | explainlikeimfive | {
"a_id": [
"djnomks"
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"text": [
"Because it would be ridiculously expensive. Earth produces about 2.6 trillion pounds of garbage every year. The falcon heavy rocket when complete, will be able to boost stuff into low earth orbit for $1,000 per pound. Sending it to the sun would be considerably more expensive than LEO. But even if we use the $1,000/lb figure, it would cost $2.6 quadrillion per year to send all of our garbage to the sun. That's about 26 times the total economic output of the entire world."
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6kpyj4 | how come we have updated data transferring cords like USB, but we haven't updated telephone cords for mainline internet connection? | Over time I know cords have updated to be able to transfer larger pieces of data faster. Such as video games platforms using HDMI now instead of the three colored cords. And I know apple is trying to use the lightning port since it is faster than USB. Why haven't we had to update the mainline connection cords that go into wifi routers, since we still use basic phone cords that have been around for ages? Will there be a point where wifi potential is so fast, that we need to update the mainline connection? | Technology | explainlikeimfive | {
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"text": [
"We have, first it was ISDN, and later DSL. But copper lines are two unshielded, untwisted wires. It's primitive technology, and DSL already squeezes everything that can be had from it, and that only if the line isn't too long, and there's no interfering equipment on the line. Also, unless you're on DSL, that's not a phone cord, that's an ethernet cable. It's a different thing entirely, there's more wires in it, there's often shielding, it's twisted pair, and speed went from 10 Mbps to 1000 Mbps on it in consumer tech."
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6kqld0 | Why do some modern millitary aircraft (E-2C Hawkeye, etc.) still use propellers instead of a jet engine? | Technology | explainlikeimfive | {
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"well the e-2c hawkeye is from the 1960s. so it's not exactly \"modern\". but this isn't a fighter aircraft, so it doesn't need to be fast. there's no need for a turbojet when the turboprop is still just fine. keepping the turboprop is cheaper and easier refitting on a turbojet.",
"Turbo-prop engines are just more efficient than turbo fan/jet engines. Basically, they can stay airborne for longer with the same amount of fuel. Particularly for something like airborne early warning, it's much more important to be able to stay aloft for a long time than it is to be able to go very fast.",
"Another feature on some prop planes is variable pitched propellers. This allows them to spin up to high rpms without any thrust than adjust the angle of attack of the propellers to provide maximum thrust at speed allowing for shorter takeoff than fixed pitch blades found in other aircraft and jets."
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6kqp8w | What is and how does the md5 checksum of a file work? What makes a checksum so feliable to know if your file is the good one? | Technology | explainlikeimfive | {
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"The MD5 algorithm is a member of a special class of function called a \"cryptographic hash function.\" What this means is that, for any data of any length, you can use the hash function to convert it into a piece of data of fixed size, that is (*very generally speaking, see below*) unique to the file that created it. You also cannot tell, by looking at the hash, what file was used to create it. This checksum lets you do something very important: verify (mostly, see below) that a file has not been changed. The reason this works is because even a small change to the input drastically changes the output of the function, so if someone says \"I'm sending you a file; its checksum is such and such,\" and you download the file and its checksum is *different,* that means it suffered corruption in transit, whether malicious or not. IMPORTANT: MD5 should not be used anymore, because its cryptography has been broken. It's weak to a couple of different attacks, which render it unable to do what it's supposed to do."
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6kr8yx | How are 2-D cartoons (like Spirited Away or Spongebob) animated today using computers? | In other words, how do you get to the 24 FPS in most cartoons from the original single drawing of a scene? There has to be a better way than just drawing a sequential set of scenes! Edit: For more context I suppose, how do programs like Toon Boom Harmony work in the context of making the continuous animation? | Technology | explainlikeimfive | {
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"Drawing is still mostly what is done to this day. It is mostly drawn with computers these days, but nonetheless there is still quite a bit of work that comes in to do with 2D animation. It's a long process from the initial idea to the finished product but when the animation part happens, most often what they will do is have a skilled animator draw \"keyframes.\" These are somewhat important frames, similar to how a comic book or manga will have, but more plentiful. From one keyframe to the next, it is obvious what motion will take place and this is when less senior animators will draw the frames in between to make it fluid. They will often use a computer overlay of both key frames along with any drawn frames to make the motion make sense (this is a big part of what \"Toon Boom Harmony\" does for example). And note, the process is divided up in each frame, there will often be a static background upon which a second layer of characters and what not is drawn on. But yes, it is a long, tedious, and often expensive job. Spongebob is a bit easier in terms of animation, it is considered more cartoony and what not, and as a long running series, they can very easily reuse old frames, backgrounds, and character poses to make this process quite a bit faster and cheaper. Things like Spirited Away also have this capability to some degree, but not much. But when copy pasting can be used, it is. The big issue is that we can easily replicate real life physics by using computers, but this generally involves going into the realm of 3D animation and there is no standard physical way to do 2D animation since these physics laws do not apply there and as a result, humans are the ones who decide this in real life. 3D animation seems to work really only when realistic things are portrayed, not the single tone/dual tone faces and large eyes of anime."
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6krc4w | I was always told not to put a fridge or AC on an extension cord. Why? | Technology | explainlikeimfive | {
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"text": [
"Refrigerators and AC units have a much higher peak power draw than most household appliances. An extension cord that isn't rated to handle that kind of draw could overheat and short, or cause a fire.",
"Anything that allows current to flow also loses a little bit in resistive heating. (Technically, this isn't true of superconductors, but since we can't make cords out of them yet, that isn't relevant here.) The resistance of a wire increases with length, and decreases with diameter of the wire. So, if you look at the power cord that comes out the back of your fridge or AC unit, you'll notice it is both short and very thick. That is because those devices draw a HUGE amount of current. The resistive losses could easily overheat the wires (and as wires heat up, their resistive losses increase - which can result in a runaway situation to melting copper starting fires!). Now, just about any extension cord you can find will be both longer than the original cords, and thinner. That means they aren't intended to handle loads that big. Additionally, the junction between the original cord and the extension cord might come loose. That can cause arcing, which again can lead to fires. It's not nearly so likely with the original cord, which is so short you really can't move it around much - and a lot stiffer to boot."
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6krzqk | Why do programs sometimes go unresponsive when you try and close them? | Technology | explainlikeimfive | {
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"Believe it or not, the close button on a program's title bar is not an authoritative operating system command. It's merely a \"suggestion\" to the current program that the user wants to quit. So the program is responsible for cleaning up and shutting down. Depending on what the program is doing, it may be unable to stop its current task immediately. It's also not uncommon that the program might have a bug that when closed at certain points will cause the program to freeze as it's trying to shut down. This would be due to a programmer error.",
"Apart from the given answer, it may be so that the quitting works like this. When the quit button is pressed, it sends a signal to a *signal lounge* (like in an airport), where signals wait for their turn to be processed by the program threads (i.e. picked up by their carrier flights). If the thread that is to process the quit signal is stuck doing something else (the plane is transporting someone else, elsewhere) it will have to keep waiting there. Or sometimes, the thread picks up the signal, but the program (airport) is so busy, that processing that signal takes a lot of time."
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6kss9k | How do people who make song mashups isolate the vocal tracks to songs? | Technology | explainlikeimfive | {
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"text": [
"Vocal-only tracks for many songs can be found publicly. For many songs for which vocal-only tracks aren't publicly available, producers of those mash-ups may have connections to labels/artists and can get the vocal-only audio for a track privately. I've done music composition/DJing/remixes for 20 years (as a hobby), and have found vocal-only tracks with which to create remixes. I've also taken songs just as they are - including instruments and vocals and all mixed together - and remixed them, splicing different sections together and overlaying additional instruments. I've been surprised with how well that works in some cases. You can search for \"acapella version\" or \"acapella mix\" on services like the iTunes music store or URL_0 & you'll find a lot of vocal-only tracks perfect for remixing. Have fun!",
"Usually if you isolate the center channel, most mixes carry the majority of the vocals up the middle.",
"Easy. Most of the music tracks come out with an instrumental version. Audio edition software like SoundForge etc have a function called \"Invert Phase\". In simple words it allows you to \"cut-out\" vocal version out of full track if you have same track instrumental version. For best clean effect Both tracks have to be same duration same quality and same tempo and volume level. Other than this if you do not have an instrumental version you can mess with qualizers and cut out most of the unwanted sound frequencies. But that acapellas are mostly garbage."
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6ksx08 | How do Esports professionals get hacks onto the systems during competitions? It seems like it would be a closed and monitored network. | Technology | explainlikeimfive | {
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"text": [
"Nobody is actually monitoring every little bit of information sent in the network, and even if they were, it would be nearly impossible to pick out evidence of a hack - you'd have to have a program cross-referencing known hacks or checking packets. If a hack is not yet known about and doesn't change game files or packets, it won't be detected. Not all e-sports are multi-million dollar affairs like League of Legends championships where PCs are furnished for every player. A lot of tournaments allow players to bring their own equipment."
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6kt28o | Why do some webpages/applets only load if you're actually looking at them in your browser? | It seems strange that pages frequently won't load if the page is open in your browser but you're looking at another tab or you've scrolled past the applet. | Technology | explainlikeimfive | {
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"text": [
"Page Visibility API ( URL_0 ). The JavaScript running on the site can detect whether the tab is currently being viewed."
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6ktq6g | Why does a high-resolution image have to load, but a high-resolution video can play thousands of frames without having to load each one? | Technology | explainlikeimfive | {
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"text": [
"[This video explains quite well how it works online, specifically Youtube]( URL_0 ) TL;DW: Youtube only sends information about changes between frames of a video. Since there is usually very little difference between 2 frames the server can just say \"ehhh take what you had last time, shift this part a tiny bit that way, job done\". For example, if you are watching a black screen, it doesnt have to send any new information, simply instructions to repeat the frame over and over. With images, there is no way to predict the future content in advance so every single pixel is sent.",
"One word: buffer. A single image needs to load because it wasn't in memory prior to you deciding to view it. A video loads when you decide to watch it and the program knows you aren't just going to want the first frame so it loads many other frames behind it so it can display them at the proper video speed. Additionally encoding of videos means that each frame isn't a full and unique picture. Rather it keeps track of what pixels are different from the last image and which ones aren't to form the next frame.",
"I'll expand on what other people have touched on here. When video is sent, there are two types of video frames sent. There's the \"key frame\", which is a single frame of video that is 100% complete with all of the pixels, color information, everything. The other frames are just sent with the pixels that have changed versus the keyframe. The keyframes are sent with regularity, depending on the settings in the video encoder. Sending a keyframe is \"expensive\" as far as bandwidth goes. If you have video that doesn't have a lot of fast motion in it, you can set the encoder to send a keyframe less often because there's less change from frame to frame in the source video. But if you're shooting an action flick with lots of motion and bombs, you need to send a keyframe a lot more often otherwise you get \"tearing\" in the image.",
"Videos mostly have very similar images after each other. So you only have to send this small differences. Defective gifs are a nice way to see how movements and image changes happen. r/brokengifs/ Many video codes use a hard limit on there data size per time. So if you have a lot of movement the image quality suffers. And if you have very sparse movement the image quality can be very good."
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6ku4m9 | How knowing mathematics is important for learning how to code a computer | Technology | explainlikeimfive | {
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"As a web developer, I wouldn't say I use much mathematics, what I do use is logic. Maybe math is heavily suggested because it forces you to think logically? On a side note, I know certain programming like motion (for games) and such does deal with math.",
"First, because computers can't deal in subjective things, only objective truths, and the only absolutely, utterly, completely objective thing we have is math. Everything else is subject to interpretation. Even physics is technically tainted; the math we use to describe physics is guaranteed to work, but we don't know if the mathematical description itself is actually right or not (although, in fairness, we're really really really sure in most cases), entirely because those descriptions were built on our own observations, and those observations are subjective. Second, the reason you use a computer is to crunch a lot of numbers in a relatively quick manner. Making a GUI or a web interface really isn't that difficult, so if you actually want to make yourself marketable with your programming ability you need to be able to get a computer to actually work hard for you. That means computations, which means math. Knowing higher-level math (particularly linear algebra) gives you a path to follow in order to make a general code to solve any sort of mathematical problem. For example, a lot of high-end computational work involves either computational fluid dynamics or stress analysis, which involves breaking down the thing you are studying into really little regions called finite elements or finite volumes. Doing so means that the equations for the individual elements become relatively easy to solve, but in exchange you end up with tens of millions of individual equations. So you take those equations and put them into a format called a [matrix]( URL_0 ), which you then solve using really elementary linear algebra. Now, the more math you know, the more you begin to understand that you can actually get the computer to recognize ahead of time how the matrix should be assembled so as to cut down the number of equations that have to be solved, and the size of those equations. This decreases the amount of time your computer spends chewing on the problem, sometimes by enormous amounts of time, and when these problems sometimes take **days** to solve, the time savings can really make a huge difference. And that's not even getting into numerical methods like Newton-Raphson method which can make things go even faster.",
"You can consider programming as a branch of mathematics. Programming functions are named from mathematical functions. SQL? That's just relational math applied. Algorithms? That's discreet math applies. GUI? I use basic fractions a *lot* when working with GUI. So what's the use? Relational maths seems 100% useless to me. Maybe if you were implementing your own database to compete with MySQL, DB2 or something. Maybe. Discreet math? I often use the methods to informally check if an algorithm works before programming it. It help me learn a problem and design a working algorithm in minutes, in stead of spending days of experimenting with buggy code I don't even understand myself. On a softer level: Maths helps me to see a problem in a logical way. See some simplicity in a complex task. And then write much simpler code with much less bugs, than if I just started coding what the customer says. And on a higher level: Studying math is a way to learn a kind of logical thinking, that is really really useful when programming and doing software design.",
"Even basic and classic many hundred year old algebra familiarizes your mind with the idea of manipulating placeholder variables through rules to get the results you want. The idea of functions which perform predictable transformations on data? Porgramming is not about memorizing 2+2=4, it's about becoming comfortable with a manipulating a wide variety of rules and transformations to get useful outcomes.",
"The type of thinking necessary to create computer programs is usually algorithmic, which is very similar to the type of reasoning needed to do mathematics and mathematical modelling. Additionally, when it comes down to it computers are built to do serial computations very quickly, quantitatively, and precisely, where humans can be thought of as parallel, abstract, qualitative processors. Any computer program can be described using some kind of mathematics. The games you play, websites you use, videos you watch, etc, using a computer rely on lots of mathematics behind the scenes that you'll never see. From a more philosophical and subjective standpoint, I feel learning mathematics in general is extremely important for anyone at any level. As someone who enjoys working out and being physical active, but also happens to be good at math, let me draw the following analogy: Squats and deadlifts are universally considered essential exercises to build a strong body - I feel the analogous \"exercises\" to build a strong mind are reading and mathematics. If you practice these two regularly I guarantee you'll notice your thinking improving in ANY activity you undertake. Thus, mathematics should be practiced for the sake of keeping your mind healthy, too :)"
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6kvfb5 | How does wireless internet work? | I can see how Internet works when I have a cable to my router / modem (with light pulses) - but how does my phone or computer resolve the amount of complex data that even simple websites are made out of wirelessly let alone a Skype call or video conference? Dear internet - How does internet work? ;) | Technology | explainlikeimfive | {
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"text": [
"Basically, much like with a wired connection, where your data is transmitted through a medium (usually copper or fiber if you're lucky), wireless internet works by sending/receiving radio waves at a certain frequency (usually 2.4Ghz or 5.0Ghz) to and from your wireless router and the wireless card located inside your computer/phone/etc. The frequencies are used to set a standard radio wave that both ends are sending and receiving constantly--waiting for something to change. The data is transmitted and received by converting binary data (1's and 0's) into a change in amplitude (ie. maximum amount of oscillation) or change in frequency (ie. how many cycles per second). This is known as modulation if transmitting and demodulation if receiving. The modulation combines the carrier signal and converted data together. (It's a lot like how radio works) Source: Networking Fundementals 2nd Edition",
"It's using radio waves like a radio, or the closer analog would be cordless phones. Wireless can't transmit at the speed of a wired connection, but for home users, it's more than enough."
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6kvx80 | What is the difference between playing music on your phone through the aux port VS the charging port? | For example, in my car, I can choose to play music through my iPhone by using the auxiliary cord or the "charging cord". What is the difference between the two from a technology perspective? | Technology | explainlikeimfive | {
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"text": [
"The aux cord is carrying a raw analog audio signal that is then amplified by your car's stereo system and played by the speakers. This is standard across all devices and is why almost anything with an aux port can play sound from almost any device. The charging cord is actually also a data cable. It can carry whatever data the iPhone tells it to. In this case, the car has the proper programming to understand the digital data sent by the iPhone. In some cases, the car can even give commands to the iPhone, such as \"next song\" or \"shuffle.\" In this case, the car needs special programs to understand different phones because they all \"talk\" differently. The main difference is that the aux cord is an analog signal, while the charge cable is a digital signal, and that the charge cable can also receive commands."
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6kwtbn | Bluetooth. How does it work? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Bluetooth is a narrow band of the radio wave spectrum, 2.45ghz, set asside by international agreement a long time ago for industrial, scientific and medical purposes. It's a low-power, low-range (1-10m) frequency making it ideal for close proximity digital communication between portable computers/electronics."
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6kx5gm | Why are the vid players on some "big" sites so unreliable? | It's gotten to the point where I hesitate to click on any vid not from youtube, simply because the user experience for other sites is so iffy. Vice videos seem to take forever to load on both my (admittedly ancient) laptop and my snazzy new iPhone. CNN, Twitter, ESPN all range from unreliable/slow loading to occasionally actually crashing my computer. Watching videos on Vimeo is absolutely torturous, which is unfortunate because they have a lot of good, exclusive content. These are companies that are focused on video and have a decent amount of funding. What is youtube doing differently that these companies aren't able to do? | Technology | explainlikeimfive | {
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"YouTube processes every single video that is uploaded to the site to use the exact same file type with the exact same settings. This particular file type is heavily compressed. Compressing the video file causes a loss of quality but it loads faster. Vimeo uses a slightly less compressed file type which looks better but might take longer to load if you have a slow internet connection. The other things that can affect your viewing experience is the physical location where the video is stored, how many people are trying to access it at once and how capable they are of accommodating the traffic. YouTube has spent a ton of money placing data centers all over the world with enormous bandwidth to accommodate the incredibly high site traffic that they have. So going to YouTube might be like traveling a mile on a six lane highway, and going to CNN might be like going a hundred miles on a winding back country single lane dirt road.",
"10 years development and experience, infinite Google money, tech, staff, and servers, directly connected to the majority of the internet advertising revenue network. Edit: The fact that everyone is using Chrome now, which is also their own product.",
"youtube has cache server in most ISP (they pay the ISP to house these cache server in) and the rest of the IP TV doesn't have that. what cache server does is that, if a video is very popular in that region, it store it in it's storage so if you are in that region and happen to click it, it downstream to you faster than you go to the google server somewhere 1/2 around the world to fetch the video. sometime, some video in youtube takes forever to load because it is not popular in your region, hence the video is not stored in your ISP cache. i work in a ISP, we have google cache servers here. it's not just a single server, it is quite a lot and google is really serious about it."
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6ky2gj | What technology advancement made LEDs become more useful than basic on/off indicators? | There've been LED's around for a long time. What happened in the past few years to make them viable replacements for just about any other type of light bulb (ok, probably not any, but hopefully the point is made)? | Technology | explainlikeimfive | {
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"Probably the most important advancement was the blue LED. LEDs have always been much more efficient than incandescent lights, but were only available in red and green, so they weren't much good for general-purpose lighting or color displays. The invention of the blue LED in the '90s allowed full-color displays, and by combining blue LEDs with phosphorescent materials, white LEDs as well. URL_0"
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6kysg2 | Who or what owns/manages the entire internet? | Technology | explainlikeimfive | {
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"Thats the beauty of it. Nobody owns the Internet. Even when some goverments have control over their countries infrastructure. The internet has a decentralised structure to prevent it from collapsing, if one node falls out of the grid or is overrun by traffic. If one way is blocked, your data will redirected over a detour. There is a reason why it's called InterNET. It's built like a net, so if the direct way is blocked, you make a detour. The ARPA created it that way, so, in the case of an incident, communications will not break down. You can every time set up a DNS Server and put it on the internet to help resolving Domain/IP Adresses. Entrance is controlled by the ISPs.",
"The ISPs are who is managing the Internet. When you pay an ISP for Internet access then that implies that you want the ability to communicate with all other computers on the Internet. So the ISP need to make sure that the Internet works for their customers. If not then the customers will switch providers. So the ISPs have different agreements with each other to exchange data packets and work together to make this work. There is a lot of technology which have been developed by the ISPs to make sure communication works flawlessly. However sometimes things break down. Often this is due to multiple failures and often involves a lot of corporate politics. When this happens customers of some ISPs will not be able to communicate with each other. To help the ISPs and other members of the industry agree on standards and work together there are a number of non profit organizations set up. You may have heard about IEEE, IETF, ISOC, NANOG, IANA, ICANN, etc. These are organizations who get support from the industry and help the industry work together. However their funds are limited as most of the work is done by the members of the industry and their power is limited to publishing a strongly worded letter. So it is quite common to see cooperation who do not follow the official standards and recommendations to the point.",
"The comments above are correct but IMO the ISPs own/manage the net. It's why we pay to use it. If they want, they can manage your usage by imposing data caps, throttle your speeds, additional fees, etc. So while the Internet is decentralized, it is owned and managed by a handful of corporations",
"Generally it's the same answer as who owns flights. Nobody in particular does, it's just hubs that link different airlines together, sometimes many share a hub. IP addresses are assigned based off of [orgnizations that allowcate them], and the routing of addresses are maintained in something similar to a P2P system, which mean it's technically possible to have the same address routed in two locations (seen it happen once, ISP fat fingered the route), and traffic just goes to the nearest server with that IP. Domain registration and management is a similar ordeal, pretty decentralized. There's either organizations acting as a quoram for internet resources, or the assets are just spread around and everyone just agrees that it is the way it is. Really, we all own the internet."
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6kz2rg | Why do some ISPs limit data usage? | Also, why are some ISPs able to deliver faster speeds than other ISPs? And while we're on the subject, if nobody "owns" the internet, why isn't it free? | Technology | explainlikeimfive | {
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"Regarding the \"nobody owns\" argument - you're not paying for internet content, you're paying for the infrastructure that enables you to access that content. Cabling, servers, cabinets, hosting centres, etc etc. Data usage is limited to restrict overall use, allowing ISPs to maintain their infrastructure at a given level without having to spend money to increase capacity. Some ISPs can deliver faster speeds than others because some ISPs have their own dedicated lines (Virgin Media in the UK uses their own FTTP lines, which they lay; BT and many other ISPs use FTTC)."
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6kzv2j | how does the gyroscope in mobile phones work? | Technology | explainlikeimfive | {
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"It's often called a gyroscope but phones actually don't have gyroscopes they use very tiny accelerometers to measure how the phone is orientated and being rotated",
"They use microscopic mechanical devices to measure forces and translate them into electrical signals, a bit like a very specialised microphone: URL_1 Also a video description: URL_0"
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6l1l4s | Why are 4K videos more crisp that 1080p videos even when the native screen resolution is 1080p? | I notice this a lot when watching YouTube videos on my pc. | Technology | explainlikeimfive | {
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"This mainly has to do with how 4k gives you more bitrate (in the context of youtube), or how much less compressed the video gets when it arrives for you to watch. You know how you can compress a jpeg image to shrink the file size but make it less detailed even though the physical dimensions of the image stays the same? Youtube does mostly the same thing, but to the video instead. When you chose 4k instead of 1080p youtube doesn't compress the files as much when it gives it to you to watch, thus leading into a better video even though the physical dimensions of the video for you is the same (at 1080p)",
"Almost all consumer cameras use codecs that do a heavy [chroma subsampling]( URL_0 ) similar to the image on the left. Because the data demands of unsampled 1080p or 4k are exceedingly high. That means in both 4k and 1080p video, the camera throws away an enormous amount of data, but because 4k starts with 4 times as much, the final output looks better.",
"It has a lot to do with pixel mapping. A scaled 4k to 1080p will have a subjectively better visual appeal than one that's captured natively at 1080p. Super sampling your source and downcompressing later will always yeild a more qualitative superior result. A number of factors are at play when down scaling though. Especially the filters used to render the down scaled image/video.",
"Subsampling A 1080p video is usually 4:2:0. That means that for every 4 pixels, there are 4 pixels worth of luminance data. 2 larger pixels for part of the color data and zero pixels for the other part 4k video encoded in 4:2:0 has doble resolution. And obviously double color resolution So a 4k 4:2:0 video is equivalent to a 2k 4:4:0 video when played in a 2k display It's sharper because it has more information even though there is the same number of pixels displayed",
"I am going to look for the link I read a couple years back. But basically it is due to how the sampling works. Images are broken up into 4 quadrants and interlaced together. With the 4k it is basically 4 1080p quadrants so when it interlaces them color/sharpness etc is a lot higher. Will post and edit when I find it. Edit: Found it: (Was a video) URL_0",
"When putting a 1080p video on a 1080p screen, each pixel has one corresponding pixel in the input image. When putting a 4k image on a 1080p screen, each pixel has *four* corresponding input pixels. That extra detail improves the quality of the image, even when they have to get blended into a single pixel for the 1080p screen. Edit: this is from the perspective of rendering software, and it may get more complex when you involve the actual monitor.",
"YouTube allows 4K videos to be bigger - more data per second. A 1080p could look better if it was a lossless format/higher bitrate.",
"When deciding how much compression is ok, a screen of the correct resolution has been used. So on a pixel level the same sized compression artifacts are acceptable on both the 4k and 1080p video. But if you show the 4K video on a 1080p display you will show 2x2 pixels on a single pixel, so much of those artifacts will be completely removed because you don't show all the pixels. If it was uncompressed you would probably not notice the difference because the 1080p video would be a downsampled version of the 4K video already, while if you watch the 4K stream your graphics card would do the same downsampling. (There may still be a difference in either direction, depending on which downsampling algorithm is better)."
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6l1r5a | What are RAIDs (redundant array of independent disks) and how do they work? | Technology | explainlikeimfive | {
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"RAID means you distribute your data over more than one disk. You tell the type of RAID with a number (RAID level). RAID 0: Called stripping, no redundancy. You basically write to two (or more) discs parallel, each part of a file goes on a different disk this means you can write (in theory) twice as fast with two disks. If one disk fails your data is of course gone (half a file or a third of a file is basically useless). In theory you can do a RAID 0 over ten disks and hope for \"awesome results\". RAID 1: Mirroring. You write the same data on two disks, you gain no speed advantage, but if one drive fails you have the same file on the other (or more disks if you mirror on more). Another common level: RAID 5: You have a parity drive. Imagine you write on five drives: four drives get part of the file, while the fifth saves some checksums you can use to restore missing information if one of the other drives fails. You get an advantage of speed (like in stripping minus some overhead for the parity) and you can afford to lose up to one drive with the data being still intact - if you lose the parity-drive it does not matter for the file, if you lose another drive you can restore the information from the parity-drive. If you lose a second drive before a new one is put in and all the data is re-calculated, you lose all data. RAID 5 writes bitwise (each drive a bit + a parity-bit on the last one). RAID 10: A combination of RAID 0 and 1. Imagine you have four drives, and you strip two and mirror them to the other pair of drives. You basically get the speed of stripping and the security of mirroring. You can afford to lose one or even two drives (one from each pair). There are more complex, uncommon or outdated RAID levels, i.e. RAID 6 which works similar to RAID 5 just with two parity-disks, RAID 4 which works like RAID 5 (which works bitwise, RAID 4 writes larger blocks out to the parity-disk). Regarding combinations: You could also have a RAID 01 (meaning stripping and mirroring is exchanged) or a RAID 51, where you first build a RAID 5 and then completely mirror (RAID 1) that or you set up a RAID 50... or... whatever makes sense for your (servers) usecase. --- Please note that RAID is not considered a dedicated backup. It protects against one (or more) drives failing and might give speed advantages but a dedicated backup is still required (i.e. if the server has some electrical damage, is stolen, burns, more than one drive fails, an ransomware encrypts it all, human mishandling...)"
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6l55qg | Difference of LCD, OLED, and AMOLED that can be easily understood | Technology | explainlikeimfive | {
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"/u/kittuboy/ is correct about *LED, but made some mistakes about LCDs. LCD basics: structure with liquid crystals and polarizers that can be switched to pass light through or block it. Three such structures with RGB color filters and white backlight make one pixel. Because of constant white backlight LCDs are bad at producing deep black color. There are several kinds of these structures. * TN, for twisted nematic, is cheap, but when you look at it from the side, colors are off — this is because its structure blocks light well in small angle only. * IPS, for in-plane switching, is more advanced, it can be viewed from any angle and generally have better colors, but it's more expensive. Also a few years ago it was considerably slower in switching from closed to open (from black to white), so IPS displays were not fit for videogames with lots of small fast changing details. They got better since. * PVA/MVA — were an alternative for IPS, a bit cheaper, a bit faster. Mostly went out of use when IPS improved. Also, TFT is not an LCD type. It just means that there is a transistor for each pixel, unlike, say, in calculator's display. It means roughly the same as Active Matrix in AMOLED. So TN and IPS actually are TFT TN and TFT IPS. Now, *main* difference between LCDs and *LEDs is that first require backlight for the whole screen even if you need only one white pixel (and some light is leaking through even if scren is set to black), while second have pixels produce light themselves and powered off pixels are completely black. Guess difference in power consumption. The only problem with *LED screens (aside of price) is that making good color filters for LCD is easier than making good color LEDs. Many consider AMOLED screen colors too vibrant and unnatural."
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6l9731 | How can my external battery fully discharge when charging my phone's battery? | So as I understand batteries, they are based on a difference of potential that, when released, produces energy. But when two identical batteries are connected together I don't get why they don't just end up reaching the same balance and instead one battery will charge the other. Thanks. | Technology | explainlikeimfive | {
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"text": [
"A lithium ion battery has a nominal village of 3.7V. When you use an external battery pack to charge your phone, a circuit pulls power from the battery, converts it into 5V (for the standard USB voltage) and sends it to the USB port. Your phone takes that 5V and converts it to a specific voltage to charge the battery, usually around 4.2 volts. So, there is at least two circuits in between the batteries, not counting protection (to prevent overheating or overcharging). The external battery only sees the load imposed on it by the 3.7 to 5 volt converter. If you took two bare lithium batteries and connected them positive to positive, negative to negative, current will flow from the higher voltage battery into the lower voltage battery until they are the same voltage. (And then they'll both self-discharge due to internal resistance) One more thing, a lithium ion battery is fully discharged around 3.5-3.6 volts. There's almost no more usable energy, but the chemistry inside still produces a voltage. TLDR; there is circuitry between the batteries controlling the flow of electricity."
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6la37b | What happens when you pause a video game? | Occasionally, I'll tab out of a game or something of a similar nature and leave the game in pause like, what happens to the game and everything in it? | Technology | explainlikeimfive | {
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"I found this one cool and decided to do some google, the first video-game to feature pause was [Fairchild Channel F]( URL_0 ), probably different video-games had different systems for implementing pause. But the basic are as follows. The buttons on your controllers/console generate electric signals to a buffer, ie the console store the sequence of commands and runs it according to the game source code. When you press pause you generate what we call an interruption, it is a special instruction/signal with maximum priority which is promptly executed. The pause stops the game code execution and basically places it in a loop which will run until the same interruption is generated again (unpause).",
"Most game are [state machine]( URL_0 ). Different state of a game might be title screen, loading the game, paused, end of game... So when you press pause (and you're in the state playing game), there is a change of state that put you in the paused state. Depending of the game this can be a menu for you to manage you inventory of simply a loop that waits for the player to unpause to get back into the playing game state."
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6lajev | How does Facebook (and other social media sites) compile a creepily accurate Suggested Friends list even when you are a new user and have given the site minimal personal information? | Technology | explainlikeimfive | {
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"Did you give them your phone number? Even if it isn't public, if some idiot installs the facebook app on their phone and has it in their contacts, facebook will link you. Same for email address - if someone has that in their phone's contacts or gave facebook access to their emails (e.g. has both the gmail and facebook apps installed). I recently saw someone from way far away with 0 friends in common who I have emailed a few times for something very specific and business-related as a suggested friend. Facebook actually [builds profiles on non-members based on members' data]( URL_0 ) and then links the two if that person ever does join facebook.",
"Phone contacts. Once, i added to my phone a guy from other city (he was on vacation) and we didn't have friends in common. Next day, he appears on facebook as a friend suggestion.",
"Using a mixture of IP addresses and cookies for identification purposes, throughout various websites and ads they keep track of and build a profile on you.",
"One of the higher ups with the company I work for is always showing up in my suggested friends. He's not in my contact list at all. No phone number. No email. Nothing. We have no mutual friends. I don't have anything linked to my workplace on my profile at all. We don't even work out of the same building or the same city for that matter. I would really love to know how that works.",
"A lot of ways. If you have the account signed in on your phone, it can read your contacts and find their Facebook accounts. An obvious way: it looks at mutual friends. If you use apps via Facebook, it could look at other people using those apps, people you've used it with and people nearby who've used it. It could and probably does track the location of users (via IP addresses and GPS) and - if it finds you spend a lot of time with particular accounts - might consider that you were friends. It might also buy data from Google, Yahoo or Hotmail about the people certain people email, and find accounts registered to your frequently contacted email addresses. Finally, it's unlikely but possible that if you create multiple accounts from the same computer, it will automatically associate them with each other."
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6lbdn2 | Why does every website seem to want me to register a username and password to use the search bar and other features? Even when signing up doesn't really accomplish anything other than waste everyone's time? | Technology | explainlikeimfive | {
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"1. More accounts = more ad companies willing to pay 2. More registered subscribers = more people that can be contacted/sent messages about promotions 3. It can benefit you-if you have an account you can keep track of your activity on the site as well as get notifications 4. Identification - you can communicate with other users and save progress for yourself 5. Bragging rights - websites and companies like to compete with each other to have more followers/members 6. Organization - it is just easier for website admins if they have a record of who visits (as in how many unique visits) as well as accountability for different posts or actions 7. It can deter robots and spam if there is a required registration, especially if the website involves commenting or threads and chat rooms"
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6lewna | How large corporations recover once they have been infected by ransom ware. | Technology | explainlikeimfive | {
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"text": [
"Any corporation with a competent IT department does regular system-wide backups on a daily basis. They also have a disaster recovery plan that allows them to stand up new instances of their critical systems on short notice. And sometimes, they just pay the ransom. They routinely put thousands of dollars worth of software on every desktop, paying $500 a pop to free them up is painful, but not undoable."
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6lgtm3 | Simulated Annealing | I have seen this in many other subreddits (r/algorithms, r/compsci, r/programming) but they're all very confusing. Can you explain the ideas behind simulated annealing, what it is, and its uses? Also, what are its uses in tech and such. Thanks. | Technology | explainlikeimfive | {
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"There are a number of problems in computer science were they optimal solution is too hard to find, but it is often possible to find non-optimal solutions that are good enough. The traveling salesman problem is the classic example. Simulated annealing is a heuristic that can often find such solutions. You start by generating a bunch of random solutions, and maybe take the top ten. Then you introduce a process that tweaks those results and take the ten best of those. At first, the tweaking is largely random, sometimes making the solution better, sometimes worse. At each successive iteration, the tweaks becomes more and more biased towards improvement, accepting smaller and smaller steps backwards. The idea is that if you have a good solution, you typically only want to look at making it better, but sometimes it has to get worse first before you can get to better. The algorithm is analogous to the metallurgical process of annealing, hence the name. In it a metal is heat, the cooled slowly so larger crystals are formed, making a stronger metal. When the metal is hot, its atoms are freer to move around, breaking old bonds and forming new ones. But is it cools, it becomes less likely to break bonds and more likely to just for new ones. The process of the tweaking becomes less random is analogous to the cooling."
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6lgur3 | Why electronic boards are green? | I think it's called electronic boards. Well, it's those boards that goes in every kind of hardware: TVs, controles, PCs, video games, etc. They are always green, and full of little components on them. This is an example of a electronic board that I'm talking about: URL_0 | Technology | explainlikeimfive | {
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"text": [
"Circuit boards are green because thats the natural color of the most common material used to make them, a type of glass epoxy. They cam be made in any color though"
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6liohg | A bad electrician can cause a short circuit, a bad doctor can kill a patient. Is hacking just behaving bad at computer science? Something every student of computer science could do? | Technology | explainlikeimfive | {
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"text": [
"Hacking isn't bad computer science, it's taking advantage of bad computer science. Someone can build a website that isn't secure, but someone has to try and exploit it for there to be any hacking. At least, that's true hacking. A lot of what the media calls hacking is actually \"social engineering,\" e.g. convincing/deceiving people to let you into someplace you aren't supposed to be. It's the difference between picking a lock on a door versus talking a security guard into letting you in."
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6lm66s | What would be the effect of having one computer connected via LAN and the rest of the computers connected via WiFi? | So lately our router seems to be working rather slow and when we've contacted our supplier the support center told us it could happen due to someone on the network connected via LAN and "taking up all the bandwidth". I've searched around the internet a bit and it seems like unless some 50MBps downloads are currently running on that computer, the effect should be the opposite. Is having one computer plugged to the router via WiFi and another computer connected via WiFi work faster than one computer connected via LAN and another one connected with WiFi? **edit:** you guys are too kind. Thanks for the help! Personally, I don't experience these problems with my PC, but my roommate keeps complaining about slow connection (he's the one using WiFi), and our internet provider asked him whether or not we have any computers connected to the router using a LAN cable, and said it might be the cause. We're leaving the apartment in a month and it doesn't really matter that much to any of us, just kind of annoying. Asking more for general knowledge since I like gaming with LAN connected and was afraid it might have an effect on other people who are connected to the network. | Technology | explainlikeimfive | {
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"Depends on the router; they're not all equal, and it's not always about the bandwidth being used. Figure a typical router's network ports operate at 1 Gigabit (1000 Mbps). A typical wireless connection is limited to approx 50 Mbps; You could, in theory, connect 20x devices wireless before matching the bandwidth a single physical port allows for. Now this never actually happens because wireless technologies, interference, processing speed, packet loss etc, never get you the full bandwidth. What's often more often the case, is the router's ability to handle multiple wireless connections to different devices at the same time is limited. You also have to consider that the \"Wireless\" connection on the router is a single interface being shared by multiple devices, and splits the wireless bandwidth between them; where the physical port is just the one device. However, not all wireless routers are 'rated' for the same wireless bandwidth. A wireless router rated for, say, 300 Mbps has to split that between all wirelessly connected devices. Now taking all that together, and assuming your actual internet connection isn't the limiting factor; having a plugged-in computer should have no noticeable impact on your wireless performance by a longshot unless it's a pretty junky router. Having a computer plugged in directly would theoretically IMPROVE wireless performance, as it's one less device to share the wireless interface.",
"IT support specialist here. Are your WiFi connected computers the ones having a problem? What is the make and model of your router? What are you trying to do on the affected computers?"
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6loave | How can a computer virus "infect" mundane/non-executable filetypes like .png files? How can opening an infected .png file be dangerous? | My antivirus software removed two .png files, labeling them "Trojan.Gen.NPE.2". Surely, .png files are hard to infect? If you store data in one, wouldn't it corrupt the file or at least make it look like garbled gibberish when you opened it? How does opening it cause problems if its opened through standard image-viewing software? Thanks | Technology | explainlikeimfive | {
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"A data file doesn't runs the virus. The viewer would. Suppose you found a flaw in photo viewer or mspaint that allowed image data to overrun the buffer and execute commands. The way you could distribute the virus would be images on website. Or upload an infected image to a /r/pics and hope for front page coverage."
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6lqh4n | How is it that if I browse something on Amazon on my PC, it shows up on my phone Instagram feed as an ad? | Technology | explainlikeimfive | {
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"To piggyback off of the previous response, companies do build a profile of you based on your internet traffic. If you're signed in to Facebook on a tab in your browser, and unless you've disabled it in your privacy settings, Facebook can sort of follow you around the internet and make note of the things you see. So if you viewed an item on Amazon, Facebook took note and will show you ads for it or similar items. Since Instagram is owned by Facebook, it's natural they would share data, which is why you see ads for the same item on Instagram later if your Instagram and Facebook are connected. Facebook is not the only company that does this, I believe Google does it, too."
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6lqotp | In music videos, how does the video play in slowmotion, but the artists still move their instruments and mouth in time to the music? | Technology | explainlikeimfive | {
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"You'd need to be more specific, since this can be done a number of ways. The most simple way would probably be to play their instruments/lip the lyrics sped up, so when it's slowed down, the tempo matches (e.g., a video at 1/2 speed would be recorded twice as fast). That, or editing."
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6lrxgy | What exactly is happening when a video game is loading? | Technology | explainlikeimfive | {
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"Simple ELI5 Answer. Suppose I have a box of Lego, and my son wants to make a Death Star with them. The box of Lego is the game's contents saved in a hard disk (HDD), the process of making a Death Star is the gameplay content that will be visible to the player (my son) at the time. Now I have 2 ways to do this: 1. Either I take all of the neccessary pieces out at the beginning, and let my son make a Death Star with them 2. Or I just take out each piece when my son's working on that particular part. The first method require my son to wait a long period of time while I prepare; while the second method require my son to wait a little bit each time he needs a new piece. After some tries I find out that the second method create hiccups during my son's gameplay, during which he has to stop playing and wait for the next piece to come, and soon he loses interest in the Death Star and give up. Finding my son's interest in making the Death Star vital for the glory of the Empire, I decided to go with method 1. But then I faced yet another problem: after requesting the construction of the Death Star my son only see me run away somewhere without saying anything. He's confused, wondering why I'm away for so long. Did I not hear his request? Or am I too busy to serve the Empire? Maybe I just forgot about him completely? I forgot to tell him what I was going to do. So I run back, telling him I'm getting the pieces and will be right back in a couple of minutes, and turn on a distracting cartoon for him to watch while I'm away. That, is the load screen. _________________________________________________________ [Source]( URL_0 )",
"The computer moves needed data from its hard drive to RAM. When doing all the calculations needed to play games, the processor needs fast access to all the data necessary to do what it does, in this case, play the game. A typical hard drive is way to slow for this, it needs the data fast. So we came up with the idea of Random Access Memory, or RAM, which acts as super super fast memory that stores data needed for running programs. But the data needs to get into the RAM in the first place, and this is why loading happens. Hard drives are once again, slow. That being said, if you use a Solid State Drive, which is just a faster type of permanent storage, your load times will be significantly reduced.",
"Before its full load game: * moves data from slow hard-disk to your computer's fast memory and video-card memory storages; * decompresses data from highly packed formats which take less space but are computationally difficult to access into unpacked ones which are easy to access; * possibly generates large dynamical level, texture, geometry and other necessary structures from templates or using some algorithm; * verifies local data with remote server and downloads levels, settings, etc if it's a network-enabled game, it takes time for those to complete; * some games do nothing for some time to show you advertisements;",
"Edit: Sorry, this comment became a little bit huge. --- All those points that were covered here are valid and correct, but its not the complete truth that applies always. I'm myself in the game development industry, so i have quite some insight into those things. TL;DR: Different types of games, different approaches. generally, the quality of assets (graphics, sounds, etc) and the size of the level affect the amount that needs to be loaded, your computer hardware defines the amount of time it takes to load those assets. Also, the higher the quality of the game is, the higher usually the base requirements of the engine are, i am currently working on a AAA game where the engine (unreal engine 4) alone is of quite some size and needs to be loaded too, before even starting up the whole game. --- Long form: Lets take some different types of games into account. A) Most simple, low requirements offline games, think of them a little bit like those old text adventures that we had in the beginning of computer games basically no loading times. B) Still offline, but more advanced games, for example fancy textures, procedural generation, etc etc. (think of some basic offline mobile game, although that might not be so much the case because most are actually driven by very advanced game engines. how expensive they are computationally differs extremely) loading times range between loading-everything-when-i-start-the-game (which might take multiple seconds, because all those graphics and assets need to be copied into RAM) and i-load-bit-by-bit-when-i-need-it where you can come up with some fancy animation or some ad popup while loading the next level, you have lots of loading steps which take very short time (like, half a second or less). C) offline open world games (think of the newest legend of zelda for example) the reason why i chose to seperate open world games is that they need to be handled substantially differently than \"normal\" games. the ability for the player to run around *anywhere* in a huge level makes it often impossible to load up all the stuff when the game starts, not only because of long wait times, but also because of limited amounts of RAM (besides, always calculating everything for the entire world is a hell lot of overkill) when developing open world games, you usally seperate the world in smaller pieces (called chunks). when you start up the game, you load the initial chunk where you spawn, and as the player moves around the game loads the chunks that the player is just about to enter and unloads those he leaves (this is called level streaming because you basically stream the level from the hard disk to the ram and have constant hard disk accesses, as it is needed). in this case you try to have rather short loading times (like one second) and if it is one predefined map you can also load it up while the player is still in the main menu. D) Offline open world games with procedural map generation (think of an offline minecraft game) when you create the map, you need to wait several seconds because the computer is generating the world (or, to be more precise, the initial chunk(s) (in minecraft a chunk is 16x16 wide, so you usually see many chunnks)) when you then load this map, you load the initial chunk(s) from disk as point C). the tricky part is now, when you explore beyond what is already generated. then, your computer doesnt have to load up the world from the disk into ram, but rather generate it on the fly in ram (which is way more expensive) AND write it to disk (well, you dont visually see the writing to disk, but that usually takes longer than reading from the disk). that is the reason, why if you are running minecraft on a low spec computer and explore further and further sometimes you see chunks of blocks appear in the distance seconds after they should be visible. the computer first needs to generate them --- That was the group of offline games. when it comes to online games, things are more complicated --- E) Online games that use level streaming. (an online minecraft game) here the term \"level streaming\" is way better than if you are just offline. the server has the complete map and actually streams it (in minecraft every block) to the client as the client moves around. here also the server handles world generation. loading times mostly differ based on your and the server's internet connection as well as the server's general hardware specification (the server need to have *all* the chunks from every player in memory, not just those from one player like the client). i've also seen games where the initial connecting-to-server process includes downloading the (whole) map (smaller size maps) and afterwards you only send \"block updates\" so if a block is destroyed or has changed. F) Online games that dont use level streaming (all the ordinary shooters and online games, Counter Strike, Call of Duty, Battlefield, just to name a few) Here you usually have a combination: because you are connecting to a server, you cannot know the map in advance like in point C) but only know it in the moment when you join the server. additionally, you have the whole process of server connecting, handshaking, authentication, anti cheat systems, etc (all that usually works in the background while you see a \"connecting to server\" or \"loading\" screen), usually only after that the actual map is loaded. so connecting to a server might take a second, then loading the map usually takes a few more seconds. G) Online games that use some mix between not level streaming and level streaming (a stateful world; prominent example: Ark: Survival Evolved) First, you have to establish a connection to the server (~1 second). next, you get the info which map to load and do that (ark is open world, so you have level streaming from the disk; multiple seconds). and then, you also need to stream the state of the world: structures players placed, houses they built, positions of players, positions of NPCs, which trees are already cut down, which arent, etc etc etc. basically a subset of all the changes you need to do to transform the \"base map\" you have on the disk to the current state. H) Game engine loading times this usually happens before anything that you as developer can control happens, so either before you see *anything* or while you still see a black screen. depending on the game engine this takes a few seconds too.",
"Games are like IKEA furniture. When a game developer makes a game, they make it in its complete state. Likewise, when a piece of IKEA furniture is designed, it's designed and tested in it's completed state. Then, like a game developer, IKEA furniture manufacturers have to figure out the best way to deliver that furniture to you. So, a game developer will take their game and break it up into pieces and compress it down into a tightly wrapped up package. Sometimes this is in the form of .ZIP files, sometimes it's in .JAR files (such as Minecraft), and sometimes it's in some unique, proprietary file type that was created by the developers themselves. No matter the file type, the goal is always the same - to break down the game into smaller, compressed pieces. Let's say you buy this game, or, in our analogy, a piece of IKEA furniture. You know what it should look like. You know what it's supposed to do. But when you buy it, it's in broken down pieces and in a compressed package. It's easy to store on the IKEA shelves, or in the game's case, on your hard drive. It's relatively small (compared to how big it would be if fully assembled - so those 50GB games would be MUCH bigger if uncompressed). Thankfully IKEA furniture comes with instructions. Games come with instructions on how to assemble the pieces. (The game engine) In the case of IKEA furniture, *you* are the CPU, and your living room floor is your RAM. You take pieces out of the box, load them into your RAM, then using the included instructions, you assemble the pieces into the final product. Large games (like Skyrim) are more like an entire IKEA store/warehouse, and you only load necessary pieces to furnish your living room (or one area of one level/stage/city/etc in your game), because there's no way your house (your RAM/HDD) can hold an entire IKEA store's (game's) worth of assembled furniture (uncompressed, fully loaded data) Loading takes time, just like it takes you time to read the instructions and put the furniture together. The better tools you have and the more people helping you (the better your CPU/RAM), the faster it is to load. Regarding HDDs vs SSDs: A HDD is like an IKEA warehouse full of manual laborers. Lots of moving parts. Prone to errors, and sometimes the workers are lazy and slow. A SSD is like an Amazon warehouse. Fully automated, using robots, super quick and efficient."
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6ltz9y | Why is a 4-digit code sufficient for banking purposes but not for most online accounts? | Technology | explainlikeimfive | {
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"Something you know, something you have, something you are. Those are the three types of security. With a card *edit: and the aforementioned ATM pin* you check two of those (have and know), so the individual security of each can be less. With an online password you only have one (know), so the requirements need to be a lot stricter to compensate for not checking off the other two types of security.",
"There's this thing called brute forcing. That's where you basically try 0000, 0001, 0002... etc. Typically, people would try the common passwords first, so 0000, 1111, 2222, 1234, 4321... etc, and then start trying every password, but that's besides the point. When you're using your bank pin, you have your physical bank card. And if you get the wrong pin too many times, that account gets locked out until you talk to the bank and get them to fix it. So somebody trying to guess your pin only gets 5/10,000 chances - and needs to actually physically have your card at that! After your card's been locked out, they can't do anything. Once you go to get it fixed, you'll get a new card and the one they have is rendered useless. They get 5 chances, total. And then they have to steal your card again, and have no guarantees that the five pins they guessed before are going to be wrong, since you could've (and should've) changed your pin! Online accounts are quite a bit different. Sure, you may have forgotten your password somewhere and been locked out of your account for 10 minutes or whatever before. But that's not the only way people 'hack' online accounts. For that, we need to explain password hashing briefly. Typically, when you sign up for an account somewhere, your password will be 'hashed'. So if your Reddit password is `123456`, Reddit would only know it as something like `$2a$06$0JXJ7T//rMLelqOfaYYEw.cwQYivfp0KkJLcGaJwH/1kV8i5Oh3AS`. Meaning, if somebody hacks Reddit and gets the database of passwords, they still won't know what your password is. Even if they try and login using your hashed password, it'll just get hashed again, and Reddit will see it as something different. Hashed passwords are also (kinda) impossible to reverse engineer. Regardless of what length password you put in, the hash will always be the same length. So multiple passwords can result in the same hash. Which does mean that it is possible to get from a hash to a password that results in that hash without brute force, you just can't get the original password. But not having the original password doesn't matter, as long as the password you have turns into the same hash. However; reverse engineering a hash like this is an incredibly difficult task, and grounds for a whole other ELI5 that I'm not qualified to write at all. Alright, so let's get back to the whole brute forcing thing. Once somebody has your hash, they're no longer bound by Reddit's wrong password limits. They can write a program that hashes passwords and checks it against your hashed password all they want. Once they get the right password, they only need to try and login once. Regular ol' computers can check millions of passwords per second - and more powerful computers built for this purpose can check in the tens of billions, or even higher. For a simple, short password it'll take a matter of seconds. Even for some of the more 'complex' passwords people think up, it's just a matter of days, maybe weeks. But not very long at all. Length is exponentially more important than symbols, blood of the first born, etc. And that's barely touched the surface of internet security.",
"*Post edited to account for a number of similar responses I keep getting.* Notice most banks don't let you use the 4 digit code alone when you do online banking. (Edit: By which I mean web banking. Mobile is a slightly different case.) When you visit a bank, you need a card (which is, as others have said, something you \"have\") and if you enter the wrong passcode too many times, the ATM can eat the card (or at least invalidate it). This renders the 4 digit code much less susceptible to brute forcing all ~~9999~~ (edit: yes, 10,000) possible combinations, since you usually only get 3 attempts. (Or more, as some people have told me.) On the other hand, web logins often don't have any physical token. If there's no physical token, locking someone out for a bad password means locking the entire account, which is obnoxious. I could make your customers very angry simply by randomly trying account / passwords until they got locked out, from computers all around the world. Apparently some banks actually do this, and my condolences to their customers. You can get away with a simpler PIN for security if you have lockouts or if you (as some banks do) tie the login to a secondary security question and a \"remember me on this device\" type browser memory. This combines your password (the thing you know) with the computer (the thing you have) to make it safer. Some people have pointed out they can use PINs for mobile banking. Those PINs are tied to the device. The first time you set up on a different device, you should need something more complex than a PIN. In this case the phone replaces the ATM card as the thing you have. For anyone saying they can log in with a PIN online only, try it in an incognito mode browser. If you can still log in with no further questions, I would consider treating that bank's security as suspect.",
"Because that 4-digit code is just a cross-check with a physical card and can't be brute-forced. It's not the PIN giving you access to the account, it's the card (or the ID when you go to the bank).",
"Actual answer is because the inventor of the ATM's wife struggled to remember more than 4, so he went with that and it stuck. The original ATM was at a Barclays branch in Enfield and recently celebrated its 50th anniversary. URL_0",
"Originally, it was intended to be longer but the wife of the creator didn't think she could remember more than 4 digits. 4 was sort of acceptable though because it was a relatively high entropy space. As well as being a 2 factor authentication (just like more modern 2 factor you're probably familiar with) Most banks now allow longer pins as well, mine allows up to 15 irrc, but most people wouldn't go that high. If you *can*, and you want to maximise security, then as many digits as possible is technically the correct answer for you, but because it's a variable amount, as long as you don't reveal how long your pin is, you can get most of the benefit of a longer pin by the entropy space introduced by the possibility of having longer pins.",
"My debit card PIN is required to be at least five digits. To answer your question, though, consider the situations in which you use the PIN: * Always along with the physical card. * Usually under surveillance (ATM or store camera). And the PIN is used for committing a transaction or verifying current balance, but it's usually not sufficient to gain access to transaction history. There's usually a limit on transactions (often a daily maximum and/or a transactional maximum, and sometimes a geographic limitation—ever had a card frozen because you forgot to tell your bank you were traveling?).",
"In the world of security you have three ways to identify someone: by something you have (credit card), something you know (pin number), or something you are (fingerprint). Online you generally only use a password so you aren't doing cross authentication because you're only being identified by something you know. If you've ever heard of two factor authentication this is what it means. If you're logging into Facebook they have the ability to send you a text to your phone (something you have) after you enter your password (something you know). Also everything online is more secure, if you can start using your banks app to pay for things or doing something like Apple Pay that will be much more secure than using card + pin.",
"Because the 4-digit code doesn't exist by itself, there are multiple authentication factors: something you have and something you know. Illegally acquiring any single one of these is fairly easy but having both is very unlikely.",
"It's the combination of possession of the card, and the pin number that completes authentication. Two-factor authentication (also known as 2FA) is a method of confirming a user's claimed identity by utilizing a combination of two different components. Two-factor authentication is a type of multi-factor authentication. The use of multiple authentication factors to prove one's identity is based on the premise that an unauthorized actor is unlikely to be able to supply the factors required for access. If, in an authentication attempt, at least one of the components is missing or supplied incorrectly, the user's identity is not established with sufficient certainty and access to the asset. Knowledge factors are the most commonly used form of authentication. In this form, the user is required to prove knowledge of a secret in order to authenticate. Possession factors (\"something only the user has\") have been used for authentication for centuries, in the form of a key to a lock. Online this could be an RSA SecurID token device. When you insert the card into machine, you have completed the first factor. If your card is lost or stolen, they instruct you to contact the financial institution so they can deauthorize it. Even if the person had knowledge of your pin, the first factor eliminates the threat. If the user is unaware of the card loss, the knowledge factor (the PIN) becomes the primary protection. There is a one in 10,000 chance of correctly guessing this pin number. After only few subsequent failed attempts, the card becomes automatically deauthorized. In some instances, the ATM machine retains the card too, including if the card has already been pre-flagged through loss reporting.",
"My bank has a security phrase for security when you call or pull money out at the bank... However, this security phrase is shown on the sites log in page as long as you know the username. You don't have to actually log in to see it. Thanks BlueFCU!",
"Answers already given are incomplete. They're missing a really big piece. If someone has managed to copy your card (card skimmer, etc), and is trying to brute force your pin, the credit card company will lock your card, and reissue a new one. There are a number of reasons this doesn't work well for online passwords. It would be akin to reissuing you a new username every time someone tried to force their way into your account. It's much easier for them to require more complex passwords and not lock accounts (or lock them more selectively [simplified]).",
"Look at the key to your house. Would you consider that to be sufficiently secure? Probably, since you cannot operate the lock without physically having the key in your hand. A bank card is no different in that sense, and it even has the bonus security of requiring a PIN",
"2-factor authentication: Pin and credit card. 2-factor authentication makes it much, much harder to get into someones account. They need the physical card and they also need your code. If they pickpocket you, they can't get in. If they see you enter your code, they still can't get in. If they see you enter your code AND pickpocket you, you're an idiot.",
"It's ridiculously more time-consuming to brute-force a PIN pad with your fingers than it is to brute-force a password with a software algorithm.",
"I don't think you got an ELI5 answer... Here is my attempt. Your 4 digit pin is something you know. In the case of a card, it is combined with something you have, the card. This combination of something you have and something you know is pretty strong. For online stuff, it is just something you know (the password), so you need to make the password more complex to make it harder for a bad guy to guess it. For mobile app based stuff, the phone can act as a something you have (if the bank does it right) which means you can often combine it with a short PIN or even your fingerprint or face (something you are).",
"Everyone else said this, but what is different about using your ATM card versus logging in to a website is called Two Factor Authentication. These 2 factors, in the case of a bank card, are something you have (the ATM card), and something you know (the PIN code). With websites, you usually use 2 items to authenticate - your username and a password. As you can see, these are both items that you know. So, it is referred to as single factor authentication. Many websites use 2FA, which is a lighter version of real-life two factor authentication. What they might do is send you a text with a code, or send you an email with a code. This is \"lighter\" 2 factor because while the phone, and (conceptually) your email is something you have, it wasn't given to you by the authenticator, like how the bank creates and gives you an ATM card.",
"As someone else mentioned, you authenticate against the card you are using, not the service. With a card only the person using it can hack it at any one time, so there is a 1:1 relationship between user and service. As such, it is much easier to block hacking attempts than via an online service, where you can be hit from any location on the Internet for the same login credentials (which is an infinity:1 ratio). A 4-digit code in a 1:1 relationship is much easier to protect than the same code in an infinity:1 relationship. In fact, for the latter there is no viable protection - all you would need is 9,999 separate bots to make one attempt apiece, and at least one would be correct. And most botnets have far more than 9,999 units. Anyhow, I think 4 digits is still woefully inadequate. Royal Bank in Canada allows up to 16 digits for a PIN, for both their debit cards as well as their credit cards. I make use of the full amount. I enjoy the strange glances when I put in my PIN, and keep the pad beeping long after I should have stopped. Many people can’t understand how I can remember a 16-digit string of numbers, but I don’t have to -- like a phone, on a card reader each number has three to four letters underneath, and I just spell out a phrase. The phrase is much easier to remember. Works just as well on phone lockscreens to keep the phone more secure.",
"It's called two-factor. Something you have and something you know. Card + Pin Pin doesn't have to be super long.",
"So a 4 digit pin can have a possibility of 0000-9999. That’s only 10,000 different pins. Most banks have a system in play that if someone tried to brute force all the PIN numbers or use a dictionary of pins, the bank will automatically lock that account/card and issue a new card and or pin. A dictionary is a collection of most likely to least likely PIN numbers. Mostly pins like 2580, 1212, 2323, 1111, 9999 and the such.",
"Two main reasons: **1. Something you have and something you know.** - If you have a physical card, that's what you have. The Pin is something you know. If someone steals your card, they can't access your account without something you know. If they know your pin, they can't access your account with out the card. It's 2 levels of authentication. It allows each to be less slightly secure. In an online account, it more like something you know (password) and something else you know (pin). Real 2FA has something you have, like a device that generates a code. You need the physical device in front of you. Whether it's a 2FA generator, or just a call or text, you still need the password (know) and the device (have) to authenticate. Having a 2FA means you don't need to remember the have so the generated number can be longer. **2. It's always been that way.** - Ever notice how password requirements have been getting harder and harder? Well, pin numbers don't have that luxury. There are too many ATMs running really old software that would require updates to make that work. It would be a change relatively similar to the one right now between magnetic credit cards and chip cards. You have to change all the ATMs out, and ask everyone to go to an ATM to change their pin.",
"Most of the time two things are needed to log into something online, someones account name and their password, there are things like 2 factor authentication, but we will ignore that for this example. So you need their account name and account password. For many things, especially games related, it's quite easy to figure out someones account name, because either it's just their email address or whatever their name is on the forums is also their account name. This is more the case for lesser secure websites though as some will have you register with your email, but you must create a separate name for forums and so on. Even so people tend to use the same email to register to things and to communicate with people, so it wouldn't be too hard for the person themself to give away their account name. So the only part of breaking into someones online account is figuring out their password and if the passwords were used like they are meant to be, as in your password, has capitol letters, numbers, symbols and is long enough, than someone trying to get into your account is simply not going to be able to, it will just take too long, the issue is that most people don't use passwords like these, they use things they can remember, so that's why you get the fido1998 passwords, which are very easy for someone trying to get into your account to figure out, since they don't sit there and type all these passwords, they get the computer to do that, which can do many many attempts, especially if that website's security isn't up to snoof and doesn't give you a timeout for entering wrong passwords. In the real world, with banking, your bank card is your \"account name\" and it's very difficult for someone to get your account name, they either have to steal the card from you or they have to duplicate the information that is on the card. So since it's very unlikely for someone to get your card to begin with, the password doesn't need to be as robust and thus can be 4 digit code. Also unlike most online accounts, after 3 failed \"log in\" attempts on your bank account will cause your card to be taken by the ATM. And then there is also the added bonus that the money is insured, so even if they somehow get into your account, you will get your money back, even if it takes a little bit."
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6luigk | Why does a weird wavy patter appear if a small chequered pattern moves across a screen? | *Pattern | Technology | explainlikeimfive | {
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"As always, there's [a relevant xkcd]( URL_0 ) for that! What you're seeing is a [moiré pattern]( URL_1 ), which happens when a repeating pattern (lines, dots, a grid, etc) is more fine than the sensor/resolution of whatever is photographing or displaying it. Think of aliasing in videogames, where an angled line has to be represented with square pixels and can end up looking blocky and \"jaggy\" as a result. Moiré patterns are similar in that the camera or screen just can't capture every detail of the pattern and so some of the pixels end up shifting around to try to approximate it as best it can."
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6lukux | How does a TV remote work, or any remote for that matter? | Technology | explainlikeimfive | {
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"Most TV remotes are IR (Infrared). What that means is that at the top of the remote there is a little lightbulb of sorts behind a red cover. That lightbulb isn't intended to emit light in the spectrum we can see but rather the infrared specturum whose wavelength is slightly longer then the longest visible light waves we can see (the color red). On the TV is an infrared sensor, this sensor can detect the infrared light. When you push a button on the remote the lightbulb flashes, sort of like morse code, and the sensor on the TV sees those codes and acts on them.",
"Open the camera app on your phone and look at the ir blaster on your remote through the camera, while pressing a button. As you can see the remote works by sending a code as infrared light."
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6luv5u | Why does Apple have to have everything in their hardware/software proprietary? Why can't they make something that's open source or uses open source components like Android does? | Technology | explainlikeimfive | {
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"They make more money on their proprietary connectors like the Lightning cable because other companies have to pay to make gadgets that work with Apple devices. Their homegrown filesystem has some sanity though: it made a LOT more sense when it was first invented years ago and the established players weren't as established, then as their OS evolved they didn't want to bail to a totally new one and break backwards compatibility.",
"Aside from the whole \"they need to make money\" thing, having control over everything you make often improves the quality. Macs, iPhones, and everything in between work well together because one entity can fine tune the details of every single piece in the system. On the Android side, there are like 5 bajillion versions of Android, all of which are subtly incompatible. The problem with software that anyone can modify is that anyone can modify it, even people you might not want modifying it.",
"It's not what their customers want. Their customers prioritize ease of installation, setup, use and aesthetics over low-cost, flexible and open solutions. Additionally, Apple markets its devices as the top of the line, so part of the rationalization of their customers is \"Why do I need all those other options when I'm already using the best option?\" Lastly, Apple is an image. Part of the appeal is the fashion statement, and to the Apple enthusiast, the idea of using a generic component that 'interrupts' that fashion statement is sort of like wearing clothes that don't match."
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6lvb8h | Doesn't it defeat its purpose if I give the credit card's 3 digit security code out when ordering on the phone or online? | Technology | explainlikeimfive | {
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"Only if the connection you have with the online site isn't secure, or if they keep that information (which they're not supposed to). The purpose of the code is to prove you're holding the real card. If no one is allowed to ask for it, why would you even have that code?"
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6lvcqm | Regarding the OnePlus5, why does inverting the screen cause the "jelly" scroll effect? | OnePlus decided to invert the panel in their new device and it seems to be causing this: URL_0 | Technology | explainlikeimfive | {
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"It's *probably* a trick of the eye combined with a software behavior. Especially considering some users with phones not made by OnePlus can get the same effect by inverting their phone and scrolling. The screen isn't updating the picture all at once. It updates chunks. If you go frame by frame on that video (protip pressing . and , on YouTube skip one frame) you may notice that certain chunks of the screen start to move before others, and it looks like the chunks near the bottom are the first ones to move. This makes it look stretched for a moment, because one line of text has moved and the one above it has yet to do so. The screen is **supposed** to update from top to bottom. Since your eye is used to reading top to bottom, the effect is hard to notice on most phones since people are looking at the top area, then the bottom area, and by the time they move their eye it's all moved to the proper position. But since OnePlus installed the screen upside down and has the OS flip the image, the graphics driver still does the \"top to bottom\" behavior."
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6lxc0v | in a keyboard, what are the little bumps in the F and J keys for and why are they on those specific keys? | Technology | explainlikeimfive | {
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"Standard hand placement for typing has both indexes on the f and j key as a resting position. Having the bumps there helps you to position your hand correctly without having to look down.",
"If you're a touch typist, you start with the fingers of your left hand on asdf and your right on jkl; - those little bumps indicate where to put your index fingers for the position, so you can make sure you're in the right place without having to look at the keyboard.",
"They are there for people who type without looking at the keyboard. You \"feel\" where to rest your fingers.",
"When you rest your fingers on the home row of the keyboard, your index fingers should rest on the F and J keys. The little bumps are just there to help your fingers easily find their spot even if you're not looking at the keyboard.",
"While everyone has pointed out that they are there primarly for touch typists who don't need to look for the keys to type without issue, there is another reason behind them being there which is an extension on the whole touch typing thing. And that factor is that typing is an accessible format and as such people with poor sight or that are blind can easily navigate their way around and continue to communicate with the world around them with this simple addition. If you know that every keyboard in your language is formatted in the same basic fashion then you know without any further work where all the main keys are going to be. If you had to without seeing the keyboard rub the entire keyboard trying to work out 'that's D' and figure out where the keys are then you'd spend a lot of time constantly recentering yourself and any actions like sipping a drink would mean spending more time trying to find yourself."
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6lxfsj | How do people "crack"software? | I always wondered how in the world people come up with keygens, and even some more complicated ways of cracking like altering registry, changing hosts files, etc. How do they initially know where to go, which file they need to change and stuff like that. Obs: I have no intentions on developing cracks or anything like it, it's just that it sort of fascinates me how these hackers can pretty much break every single software out there. If this has been posted already, my apologies. | Technology | explainlikeimfive | {
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"Each method has its own way of circumventing the security. Keygens are created by figuring out the semi-random method that keys are generated, and making a new key that conforms. Registry altering works by injecting code into your registry that the program looks for to show you purchased it. File editing will either work by adding in a known license file (similar to registry editing, only using regular files) or by changing how the program looks for the licensing. They are created with a combination of studying the program in question (for example, comparing the registry of a computer before and after a successful installation), understanding how programs are developed (to narrow down algorithms), and trial and error (If something doesn't work, revert to last known good set and try again)"
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6lygem | Tesla's massive new battery in Australia | How much can the battery power? Will it be used to power Australian cities or private ventures by the company? How will the solar power be gathered, massive solar panel fields? | Technology | explainlikeimfive | {
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"So you have people who use power when they need it. Hot day : crank up the AC (lots of power). Everyone getting home from work around the same time: stuff turns on. Rise and shine wake up, endless coffee kettles. Power plants work best when constant, and wind farms and solar are up and down whenever the weather and time of day dictates. So for a power plant, the idea is \"predict what you need, and make a bit extra waste to cover if ur wrong\" sorta. A battery fills in the ups and downs, levels the hills sorta. Crazy hot day and normally getting a brown out? Battery picks up the slack. Use wind power and it's calm while everyone is coming home from work to watch a big game on tv? Battery fills in for awhile till the weather changes or a power plant can assist without extra load. Solar panels working hard in the midday but you need that evening push of more power? Save it for later. If it works properly it's just there to save power for when people need it and it's short (solar at night). This way you don't have to make extra or get it from somewhere else when times are hard. If it could really be used National scale (not close yet) u could collect sun during the day to use at night or cloudy days for long times ahead. This allows you to just use solar or wind or one power plant for an area etc etc, sorta simplifying everything What they use it for and how long will it last depends heavily on if nearby industry and such uses it, if it's tied into other things, how well it's being charged or how many people are draining it at any time (how shit can the local system go that the packs have to do damn near everything)"
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6lzhl6 | Why can you see a full preview of your video your editing yet it takes a really long time to render it? | Technology | explainlikeimfive | {
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"Why does it take a short time to count from 1 to 10 yet it takes a really long time to count from 1 to 100,000? The incredible increase in detail between a preview and a render, which means an incredible increase in the number of computer operations to render that detail, is what takes the time. An artist can draw a stick man in 10 seconds. This is like the low quality preview. The same artist might take 10 hours to draw a photo-realistic rendering of a full body. That's why there's such a difference. But your computer and the software are the artist in that analogy. This is overly simplistic, but... well... ELI5, so...",
"Specific to your question: The preview window is uncompressed video. When you render, you're generally compressing. But it also has a lot to do with system I/O loads (primarily hard drive and CPU power). For the sake of my post, I had simple video that is 2 minutes long with some minor effects in Davinci Resolve. Idle, Davinci Resolve is eating up 4.8GB of my memory and 0% of my CPU and drive I/O. On preview play it eats about 20% of my CPU, and about 1% of my drive I/O on my SSD where the source file is. Encoding the video to Quicktime 1080P Uncompressed provided a 15GB file and took 1m:43s. It jumped up to about 40% CPU utilization from Davinci and continued to use about 4.8GB of memory. Quicktime also used about 40% CPU utilization and 800Mb of memory while encoding uncompressed. My platter disc was hitting about 20-30MB/s of transfer. Compressing the video to Quicktime H.264 took 1m:50s and wound up as a 500MB file. However, Quicktime used about 60% of my CPU cycles, still around 800MB of memory, platter disk IO was significantly less kind of jumping between 5MB and 12MB per second. Worth noting, is that I am running a 6 core, 12 thread, high frequency processor with gobs of memory. The H.264 processed more and wrote less. It took many more CPU cycles. The Uncompressed file had less impact on my CPU, but had to write 30x more data. If you're running minor real-time effects that will be rendered when you process, this can peg your CPU and add some time during the render if it's set to give a certain level of detail for preview, and another level of detail for render, but the generally, there is not this level of variance on minor effects and most modern CPUs will chug along like it's not an issue. Stuff like scaling, transparencies, movements, shutter effects, minor effects like grain, chroma keying, or alpha flipping. Most effects that you'll find by default in the application you're editing your timeline in are pretty basic. It's where you get to the more specialized effects where this matters, but you're probably not doing those as generally you'd want to do a pre-render in another software package and import to the video editor where you manage your timeline. But if you're doing that level of effect, you're probably aware that's what you should be doing."
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6lzz1y | How will Elon Musk's battery fix South Australias energy problem if it can only power 30k homes? | How will it force prices down as the premier claims? | Technology | explainlikeimfive | {
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"It won't 'fix' everything on it's own, it's when you combine it with all their other power stations it provides (in theory) enough extra power to make up for current shortfalls. It needs to be noted also that it won't only be connected to just 30k houses, it will be spread over the grid. It provides the equivalent power for 30k homes, but this will be shared by everyone in SA. And it will do it (in theory) for a lot cheaper than the current methods (esp coal). The initial saving won't be much (maybe a few dollars on your bill) but what it means if it works is that when it comes time to build new power stations/replace old ones they have a better cheaper option available. Long term, this will mean more similar projects will be built, causing (again, in theory) prices to go down, because people will naturally want the cheapest option - as long as it works."
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6m06u1 | How fast is the fastest computer? | Technology | explainlikeimfive | {
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"The fastest computer in the world is the Sunway TaihuLight, which can do over 93,000,000,000,000,000 floating point calculations per second. This means that you'd need around 71,000 Xbox Ones working together to match it. > Like say I wanted to download a movie, what kind of wait time am I looking at? Downloading a movie is about the speed of the network connection, not the speed of the computer. The fastest computer in the world wouldn't download a movie any faster than a 10-year-old cellphone on an average internet connection.",
"There is a list of the top supercomputers in the world that has been published twice a year for many years now. The speed of these computers are not measured by concepts such as \"download speeds\", but in the number of operations they can perform per second. This measurment is called FLOPS or Flop/s - floating point operations per second. (Floating point here refers to a type of math that computers use.) Current generation of CPUs can perform something like 100 GigaFlop/s meaning a billion operations per second. Most supercomputers are build by connecting many, many computers together. The current top contender on that list is a computer called *Sunway TaihuLight* in National Supercomputing Center in Wuxi China. It has measure peak perfoamnce of 93,014.6 TFlop/s This means it can carry out almost a hundred quadrillion of these operations per second. The fastest supercomputers in the US are not in the hands of NASA but the Department of Energy which uses them to do such things as simulating nuclear bombs. If you tried to measure a human on the same scale as supercomputers he would not fare well. A human trying to do something like division of numbers in his head or using pen and paper would require seconds at least to come to an solution. So they would have something like 0.1 Flop/s which is a million times a million times ten thousand times worse than a supercomputer. Of course human brains are built on completely different principles and optimized for completely different operations which is why we build tools like computers in the first place to help us out cover for our weaknesses. Your question about the downloadspeed is a completely different point. Your downloadspeed is based on what your computers netwrok card can do and what your Internet company can offer you. Most home computers have a single Gigabit network card build into them but very few ISP offer fast enough connections to make use of that. You can buy and plug a 10 Gigabit network into your computer but unless you want it to connect it to another computer next to it which also has a 10 Gb card that won't help you much. If you have an ISP that offer you a full 1Gbit Internet your current PC would be able to use (almost) all of that and be able to download an entire DVD in less than 40 seconds (if someone on the other end was uploading it that fast). You don't need a supercomputer for fast download of movies your current one will do fine you just need a better ISP.",
"For your bonus question: It's currently estimated that the human brain can perform about 38,000, 000,000,000,000,000 operations per second (38 x 10^18, or 38 exaflops). Compared to the most advanced supercomputer currently in existence, Sunway Taihulight (93 x 10^15, 93 petaflops, or 93,000,000,000,000 operations per second), the human brain vastly overpowers it. And unlike what the other posters have said, the brain actually **does** work a lot like a supercomputer in the way it works. Neurons can be either \"on\" or \"off\", pathways are either \"used\" or \"not used\", which makes it a binary system. It's just that most of it is being used on the trifling task of **keeping us alive at any given moment**. In 2014, some Japanese researchers tried to match the processing power of just 1% of the brain to the K computer. It took K just over 40 minutes to perform the same number of calculations as just **one second** of brain activity. Here's the summary of the study. URL_0 The reason for the brain's overwhelming power is in how it is constructed and in how it talks to itself. Synapses are being constantly modified by neuron and chemical interaction, whereas computers **only** use binary."
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6m0y9i | How/why is Elon Musks Australian battery farm such a gamechanger in the energy business, especially in regards to fossil fuels? | Ultimately a battery is just a storage device for energy. We put energy in, convert to physical form (cathode/anode and electrolytic solution). Then when we need energy, we allow a chemical reaction to occur, releasing energy again. I keep hearing about how his battery farm is a gamechanger that will put fossil fuels out of business. But how is that possible? If a market experiences big swings in demand throughout the day, then the battery farm will benefit any generation company; not just renewables. Especially since they can just put their a lot of excess into the batteries without having to pay for it; as opposed to a standalone battery farm that buys at night and sells during the day. It's already the same idea as pumping water up a mountain at night, then letting it flow back down and turn some turbines for power during peak hours. (Just chemical instead of physical) Heck, with the money they can throw around, a fossil fuel company can probably invest and benefit more than a smaller (not all are small) solar/wind company. | Technology | explainlikeimfive | {
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"Because energy generation like wind, tidal, and solar aren't consistent. It's easy to shovel coal into a furnace around the clock, but the sun is only out during the day. With large battery stores, power can be generated when the conditions are favorable (regardless of draw) and stored for when conditions aren't favorable. It makes solar, wind, and tidal much more viable for large-scale power."
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6m1j5z | why do stores or companies buyback used, broken or old electronics?? | I was at the mall today and went into a Virgin Megastore and they had this offer where they take your old devices such as an old IPAD or IPHONE and give you a gift card for about 100 dollars or so depending on the condition of the old device. I've noticed some other places that would exchange your old device with a new one and you would only pay the difference in price for the new one even though they do not sell used devices. what i cant figure out is how do they make profit out of doing such things?? is the recycling of the old devices generate enough profit to make worth the trouble? i feel like im missing out on something here and would like someone to explain it to me, thanks. | Technology | explainlikeimfive | {
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"Most probably go to their sister divisions within the corp as a refurbished items. They'll have another store sell the refurbished items for a profit. Many of these stores also require a new contract for phones to do am upgrade trade so they make their money off of your monthly contract and/or sale of refurbished items elsewhere in the company.",
"1) They can refurb it and resell it or scrap it, sometimes for a profit, sometimes for a loss. If nothing else the gold in the electronics is worth running it through a blender. 2) You aren't really getting a good deal :D Sorry. It's like a coupon in the paper \"50 cents off this wash paper that costs a dollar more than the generic brand\". The markup on the stuff they sell is HUGE, so even if you get a 100$ coupon for a 10$ broken phone they are still making hundreds of dollars when you buy a new Iphone and service plan. 2) is really it. That's also how cell phone companies can offer to pay off your old phone (which often takes the form of a loan...). The profit margin on what they sell you is HUGE so even if they lose some money up front they make it back tenfold by the time your 2 year contract is up."
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6m27r1 | How does resistance of an earbud affect the quality of the sound (eg: 32 ohm vs 150 ohm) | Technology | explainlikeimfive | {
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"Essentially, when audio is played through a speaker, an analogue signal is sent to the speaker which causes the wire attached to a membrane to gain a magnetic charge and oscillate due to being very close to a permanent magnet. The higher the impedance rating of the speaker, the more voltage is required to drive the coil. If more voltage is required, you're able to fine tune the signal much better - changes in voltage have a smaller effect. However, this is all at the expense of volume - a high impedance speaker will be unable to produce the same volume as a low impedance speaker driven with the same power. High impedance speakers are typically used to make up for the tiny imperfections in an amplifier circuit caused by signal crosstalk or other induction issues. Most DAC/AMPs are shielded to minimise this, however there's always some issues that creep in, therefore you're able to account for them with a higher impedance output. However, because higher impedance speakers are more difficult to drive, they don't have the same high frequency response as the lower impedance speakers. Ultimately it's a balance issue that the user must choose - higher frequency range and louder volume vs better accuracy (for lack of a better word) at a lower volume."
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6m5af7 | Why people create their own APIs ? What can an app or website do with an API that it cannot do without it ? Why people make API before the app or a website ? | Technology | explainlikeimfive | {
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"text": [
"An API allows two pieces of software to communicate politely to each other allowing a set of instructions that will achieve something without having to know the internals of the software you are accessing",
"Okay. Let's the take infamous example of a car. Now let's think...what are all the things you can do with the car? * Turn it on * Turn it off * Change gears * Press the accelerator * Press the brakes * Steer it so on and so forth. Now, for each one of those actions did you have know any of the particular details of how it's actually done? Did you have to know anything about the internal workings of the engine, how the transmission is engaged or how the fuel is injected or any of that stuff? Nope, not at all. You just had to put the key into the ignition, turn it and presto the car turned on! That's as far as the interaction with you and the car goes as far as how it is turned on. Nothing more, nothing less. Now, what if the car manufacturer didn't do that, but instead provided you with a panel of tons of switches and buttons and told you in order to turn the car on, you'd have to operate the signals and buttons in a very specific ordering and also have to attached this wire here and do this and that, wouldn't it get very complicated and perhaps very unsafe/not secure? By abstracting away the complexities and just giving you the basics of what you can do (or in programmatic terms, *call*) the car manufacturer made it more feasible for you to operate his car and use his products. What would you be more inclined to use? Something that is really complicated to operate or something that is very simple, provided they had the same functionality/benefits/terms of use? Obviously, the easier one! Now, what would make sense for the car manufacturer to do/get his product to what the customers want the fastest possible? Think from the user's perspective -- at a large abstract scale (Hmmm...what all functionalities would my app/service have for my users?) and then work down into the nitty gritty application or take an overly complex system and create abstractions for it from the ground up? The answer is actually both but more often than not, the former is \"easier\" to do and is more \"client/customer\" facing than the latter."
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6m6ul9 | Why is it so hard to synthesize more superheavy atoms? | I understand that it's more than just accelerating and smashing two elements together, but why does it take so long to synthesize new superheavy atoms? Is the energy required in exponential correlation with the mass? Are they too short lived to be detected? Don't we have a sensitive enough detector? Are there always more stable "waste products" that form instead of the heavy atom? Don't we know which elements to combine to amount the proper balance of electrons, protons and neutrons? | Technology | explainlikeimfive | {
"a_id": [
"djzbziy",
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"text": [
"They are *extremely* unstable, and hard to assemble in the first place, because you are cramming so many protons into a single nucleus, and they mutually repel.",
"The nuclei of the atoms repel each other. To have some chance to combine, you have to shoot them together at high speed. How imagine you shoot together two snowballs at very high speed - and then hope they stay together instead of breaking into many pieces. It can happen, but it is very rare. Accelerators have easily enough energy to collide the nuclei, but most of the time you get a lot of smaller atoms that are known already. In very rare cases, you get a superheavy nucleus (and still some other \"debris\" flying away), and you have to find these very rare events. > Are they too short lived to be detected? The opposite: They have to decay. Finding their decays to known types of atoms is the way they are identified. A stable atom would just get lost somewhere in the machine, and it would be extremely difficult to find it. All these experiments with superheavy elements are about the nucleus only. The nuclei can collect electrons later, but that is typically not what scientists are interested in (the nuclei usually decay too fast to study what the electrons would do)."
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6m6xuu | How do game developer fix video game performance(fps) on games that runs poorly | Technology | explainlikeimfive | {
"a_id": [
"djzdexs",
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"text": [
"They optimize the code to make it more efficient. For each frame to be drawn to the screen a certain amount of work needs to be done. You can reduce the amount of work to be done to achieve the same result or optimize how you are doing the work to run faster by writing better code. Think of an assembly line of workers producing something in a factory, if they are not producing enough items per hour then changes in how the assembly line operates can be made to speed things up. Replace \"items per hour\" with \"frames per second\" and you have the same kind of thing. There is always ways to make code more efficient however they are not always found the first time the code is written and often developers go back and spend time optimizing after the game is finished.",
"Off the top of my head, i could say that they could make the game use more resources(it was using 6 cpu cores, now it's using 8) and/or it could make the game not so demanding, not render things that don't need to be rendered (geometry the player will never see), tone down foliage, along with some more complex stuff that sort of go over my head, they might do bug fixes where certain things are happening that don't make sense maybe the game is running the equation 2+2=4 a trillion times a second when they don't need it, so they go in and make sure that doesn't happen"
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6m6yjx | What makes nuclear waste such a big concern as opposed to natural radioactive elements? | As I understand it, uranium for instance, is mined, then goes through a refining process, is used in power plants. Then, it is considered waste and it's burried very deep under the ground, because it is radioactive and dangerous People are very concerned about this, and this is not considered a real solution, but we've had natural radioactive elements in the ground for billions of years, and they have not affected our health in most cases How are nuclear waste different, and why is it not considered a solution to keep them under the ground? | Technology | explainlikeimfive | {
"a_id": [
"djzgzwl"
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"text": [
"Three things: 1. Nuclear waste is made up of many different elements, with different levels of radioactivity, than is uranium as mined in the ground. It is also much more concentrated. The uranium ores, for example, that are mined in the United States have maybe 1% uranium per mass of rock. And while the uranium decay chain is a long one, and contains some nasties in it (more on that in a second), that means that the amount of radioactivity you are going to be exposed to from it is pretty minimal, because the total material is pretty minimal. 2. Natural radioactivity can and does pose significant health hazards. Uranium in the ground, deep below you, poses virtually none. Dirt is a great \"absorber\" of radioactivity. However radon, which is a uranium decay product, can be \"exhaled\" by uranium-bearing ores and, if in high concentrations, can present a serious health hazard. [Around 20,000 lung cancers]( URL_0 ) are attributable to radon exposure annually in the United States each year, making \"natural\" radioactivity the second-largest lung cancer source after cigarette smoking. People who work in places where uranium is mined and concentrated also have to take relatively burdensome precautions (mostly ventilation for the radon) to avoid materially increasing their lung cancer risk. And while it is hard to tally up what contributions to the cancer rate are caused other sources of natural radioactivity (e.g., high altitude, living around large amounts of granite, etc.), the \"base\" lifetime cancer risk in the USA is around 40%, with about half of those cases being fatal, and natural radioactivity likely contributes something to that. So there is a naturalistic fallacy in your question. 3. The main problem with nuclear waste disposal is not that keeping waste underground is inherently a problem. As with all waste disposal (radioactive or otherwise), the goal of taking something dangerous and isolating it from the ecosystem, or diluting it to safe levels. Burying nuclear waste is a form of isolation and, if the waste containers and the repositories stayed intact and isolated, it would not be a problem at all. The tricky part is in guaranteeing they will stay intact and isolated — water, for example, has a nasty way of finding its way into underground vaults. Over the long term, that means rusting canisters, leaking waste, etc. This isn't an unsolvable technical problem, but it is a non-trivial one. It is coupled, in the United States, with a political problem: the waste repositories have been required, by the courts, to be certified as inviolable for 10,000 years. No engineering structures known to man have lasted that long, not even Stonehenge (which, while interesting, is hardly a nuclear waste repository, and is hardly perfectly preserved). So it's hard to even know where to start to try and assert that you can make something that will last that long. That's a regulatory issue mixed with a technical issue. We might also gesture towards the fact that people consider nuclear risks different than normal pollution risks — nuclear falls into what the risk perception scholars call a \"dread risk,\" something that people feel is alien, that they are out of their control, that is not a \"normal\" risk. It results in both an overinflated fear of nuclear matters (nuclear risks are real, and waste issues need to be taken seriously, but they are not the major pollution or environmental issue of our time — the volumes of nuclear waste that need to be dealt with are relatively small, and there are \"good enough\" ways of dealing with them in both the short and long term), and also an under-appreciated fear of other pollutants (coal exhaust exposes people to more radioactivity, and health hazards in general, than nuclear waste ever will; if nuclear technology produced even 1% of the fatalities attributable to coal per year, there would be no nuclear technology). I would just note that the acknowledgment that public perceptions are \"out of whack\" with the health realities does not mean there are not health realities that need to be dealt with carefully."
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6m743b | How come playing Counter Strike at 200FPS feels way smoother than playing at 60FPS even though my monitor is capped at 60FPS | Technology | explainlikeimfive | {
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"djzef0r"
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"text": [
"I think its because there is a frame rendered just before the screen refresh each time that is much closer to the actual state of the game. At 60 FPS you might get a frame anywhere in between the refreshes: [ | ] Refresh At 200 FPS there are more up to date frames rendered before the refresh: [ | | | ] Refresh Since that last frame was rendered closer to the refresh you should be seeing tighter consistency between what is really happening and what is on your screen at refresh time. This is what my understanding is anyway, I could be 100% wrong."
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6m81bc | How does HEX color code works? | Basically what the question is. At a machine level, how is it that this code reflects a color in monitors? | Technology | explainlikeimfive | {
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"text": [
"Hex code are 6 characters, like so: FFFFFF Each group of 2 represents a colour, either red, green or blue and range from 0 to 255 in value (00 to FF). So say we want to have bright yellow, we would it code it like this: FFFF00 which would represent the RGB value 255,255,0. It is also possible to have an 8 character hex code, where the last 2 would represent the alpha, or transparency, value or the colour.",
"The code consists of 6 digits. Each byte is represented by 2 hex digits - so a colour code consists of 3 bytes of information. And then, the first byte (first/second digits) simply corresponds to how much red is in the colour, the second byte corresponds to green, and the last byte (final two digits) is the blue."
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6m841b | How does the entire staff of a major motion picture get paid? Are they salaried or job-to-job? | Technology | explainlikeimfive | {
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"text": [
"It depends. The movie itself will only have a set budget and pays for the 'wages' out of that. So there's only enough money to pay for that job. So technically everybody is getting paid job-to-job. But movie studios want to keep good workers available so may be prepared to offer people contracts for set periods of time to keep them around. A lot of work is also outsourced to other companies who will also have a mix of permanent staff, contract workers and short term/day labourers. They will often have a set amount paid to these companies, who then decide how to split it amongst their workers. Often a lot of people/companies (esp back of house stuff like editing, effects, etc) will be working on multiple projects at once. Then you have situations where production/technical companies are also financial backers of the project and how much everybody gets paid will depend on how much the movie makes. In short - it's complicated and each studio, movie, company, and worker will have a different way of doing things. But the more technical your job is the more likely it is you have a favourable deal. The coffee guy for example probably gets paid daily (or works for free to get a foot in the door). The labourers like riggers, set builders, etc would probably be contracted for the length of the movie. The technical labourers like the camera crew, lighting, sound, etc are usually studio employees shifted around between projects. Ironically enough the top end workers like directors, producers, editors, casting agents, (and actors) are hired from job to job. But also paid enough to make it worthwhile. But none of this is set in stone and working in the 'entertainment industry' is one of the most unstable jobs you can have."
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6m867k | Why are valve amps so much more powerful and louder than solid state amps with the same wattage? | Technology | explainlikeimfive | {
"a_id": [
"djzm3hd"
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"text": [
"Valve amps produce a subjectively pleasing sound when they are driven past their \"clean\" limits. Among other reasons, they tend to distort (and generally reach limits) in a more gradual way than solid state amps. So first off, you're intentionally exceeding the limits whereas you're staying within the limits of a solid state amp and using some separate function to create the \"overdrive\" or \"distortion\" you're looking for (if you want any at all). A 50 watt tube amp is pushed to, or beyond, 50 watts just to get a pleasing overdrive sound. A 50 watt solid state amp is always kept below, say, 45 watts to avoid its less-desirable overdrive sound. Secondly, the tube amp creates distortion sooner due to its \"less perfect\" operation, for a number of reasons. This results in a \"clean\" power rating that occurs earlier and below the absolute limits of the amplifier. With a solid state amp capable of outputting 8 volts into an 8 ohm speaker, that creates 1 amp of current and 8 watts of power. But the \"clean\" sine wave contains less energy, in the 6ish volt average range, because a natural \"clean\" sine wave sound is not maximum power all the time, it's a smooth shape. Distorting the hell out of the signal, outputting a square wave, and therefore driving max power all the time time, can push output to that 8 watt physical limit. But a tube amp which can output 8 watts without distortion could perhaps keep pushing to 10 volts and 11ish watts... just not cleanly. The limit of its undistorted operation came way before the absolute physical limits of its operation. So when you do overdrive it and push the maximum physical limits, the power is higher than you might expect from its rated output. Again, this is because its rated \"clean\" output is created by a number of limitations other than absolute power supply/peak output limitations."
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6m87hv | what purpose do cooling towers serve if reheat will be required? | Cooling towers are used to cool down the water. Please note that I am not asking about the condenser. The condenser is used to convert the steam to hot water. The cooling towers take that hot water and cool it. But my question is: why cool it if it needs to be reheated anyway? | Technology | explainlikeimfive | {
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"text": [
"Cooling towers are condensers. The purpose of the cooling tower is to cool the steam down to water so that you can reuse the water in whatever system it is a part of. Cooling towers are used as part of the AC of some large buildings, as well as the way that power plants dump excess heat and keep from blowing up. If they just vent the steam into the air they have to consume more water for the system. Far better to cool it and reuse it.",
"In the image you linked in a reply ([this one]( URL_0 )) shows you why if you look closely the water loop running through the turbine and boiler is seperate to the loop to the cooling tower and they come together in the condenser. This means the condenser only cools the steam down to water in the turbine/boiler loop and the cold water from the cooling towers is what does this. So to cool down the steam to water you need yo take the excess energy out. To do this quickly and efficiently you need a high temperature gradiant so the water from the cooling towers need stop be as cold as you can get it. Hence the towers. The water in the boiler/turbine loop won't drop much below boiling point to save the energy needed to turn it to steam."
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6m8plk | Why is it that seemingly every website/game/ANYTHING wants me to log into Facebook to use it? | Technology | explainlikeimfive | {
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"A lot of people seem to be saying \"so they can target ads\" or \"so they get lots of information about you\", but that's not really the case. Let me explain a bit about how this works. When you click \"log in with Facebook\", the website sends you to a website controlled by Facebook (not them) that asks you to log in if you aren't already logged in, and then asks you to authorize their application to access certain information. If you click OK, then it sends a token to that website allowing them to access only the information that they requested access to. That Facebook page will tell you what they are requesting access to. The list of things they can ask for is on [this page]( URL_0 ), but most of these websites just ask for the basics- public_profile and maybe email, so they'll get your name, profile picture, and your email, but they won't have access to your likes or your friends list or anything like that. If they do want access to that other stuff, the page will tell you. You should always read this page to make sure that random websites aren't requesting permission to spam all your friends and like pages on your behalf. The advantage of this to Facebook is that you have more stuff tied to your Facebook account so you become more tied to the Facebook ecosystem. They also know what app/website you're using, but they don't know enough about what you're using the app for to target any additional ads to you. For the website, there are two main benefits. First of all, the sign-up flow is way easier- it's literally just two clicks if you're already signed in to Facebook. If they need a bunch of information from you, they'd otherwise need a much longer sign-up process, and a lot of people tend to give up if the sign-up process is too long. Second, they get to take advantage of all of Facebook's security. Facebook has something like 17,000 employees. They have whole teams just dedicated to keeping your information safe. Joe's Forum does not have whole teams dedicated to keeping your information safe, so it's much more likely that Joe gets hacked than Facebook. That means Joe doesn't have to worry about stopping hackers from creating tons of fake accounts, and if his website does get hacked, the hackers won't get access to all of his user's personal information (since all of that is stored in Facebook).",
"The site needs you to make an account. But it's a hassle to make an account. If you log in with facebook the site gets an account to refer to you by, and you don't have to put much effort into it. It also makes it easy for you to tell people about their thing if they can convince you it's good, so you're more likely to do that. Facebook has also made it really easy to use it as an \"everything\" login to keep people engaged in facebook.",
"I think OP's question has more to do with \"why do I need an 'account' just to read an article about the National Zoo pandas?\" The answer is that you don't, and all these comments about how \"the FB API is easier; why reinvent the wheel?\" are completely missing the point.",
"Everyone here is commenting on why **Facebook** wants there to be login buttons without talking much about why **developers** choose to use them. For us, it's all about simplicity and \"friction\". Simplicity means that's it's stupid easy to get an API key from FB then copy and paste some code instead of creating the form, storing the information, and making sure it stays secure. I mention the concept of \"friction\" because there are tons of website out there competing for your attention. A user is more likely to try out a service if they can click a single button and go instead of taking the time to fill out a sign-up form.",
"It's easier for me as a developer to use Facebook's sign up process than it is to develop and support my own user authentication framework.",
"almost all the information needed to sign in/make an account with these websites/games/apps are already attached to your facebook nearly everybody that uses these websites/games/apps has a facebook, so it expedites the sign up process by taking your information from your facebook and making an account"
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6m9oi5 | How does procedural generation work? | Technology | explainlikeimfive | {
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"text": [
"In many video games, the world is manually generated, and hard-coded into the game. There will always be a wall at this location, there will always be a castle at another location. The wall will use a pre-drawn texture that looks like stones. There are some issues with this. If you want a large world, you're going to have to store the exact locations of every object. You'll have to store the texture of every different type of object. This means your game could get pretty big. Procedural generation is a broad category, but the principles are pretty much the same throughout. Use an algorithm, and usually some randomness (computers are pretty good at creating numbers that appear to be random), to create a world or a texture on-the-fly, instead of loading it from a file that was distributed with the game. Let's say we're building a dungeon game procedurally. When the player starts, we'll throw him into a room. We haven't determined what the room looks like, but we have some rules. 1. The room may or may not contain a table and a book 2. The room will contain 1-4 doors that lead to other rooms 3. The room will contain 0-5 monsters So before we show the player anything on the screen, we need to draw the room. We'll ask the OS for randomness, like rolling dice. We'll use that to determine whether or not there is a table and a book, the location of that table and book, the number and location of the doors, and the number and type of monsters. Having created the room, we'll store it in memory (in case the player comes back) and put it on the screen. As soon as he walks through one of the doors to another room, we'll follow the steps again to create another room and add it to the world we're building on-the-fly. The same thing works for open worlds (like minecraft). Instead of rooms, we often think in terms of chunks. When the player first jumps into a new game, we'll use a set of rules and randomness to generate the chunk the user is in, and the chunks around the user. As the user moves, we'll generate new chunks on the horizon, so that he always has a place to go. Procedurally generated textures are similar. We can have an algorithm (generally a type of fractal), a set of rules, and, optionally, a source of randomness. When the player looks at the object that needs the texture, we'll run that algorithm right there and paste the output on the item he's looking at. That way we didn't have to ship a large texture file with our game -- we just wrote some rules that create a texture that looks like a stone, and the player's computer created it on the fly. There's a ton of variation from game-to-game, but the basic principles are the same."
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6mbcyt | How dairy companies take out the lactose of their dairy products? | Technology | explainlikeimfive | {
"a_id": [
"dk0b4yp"
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"text": [
"Lactose isn't really taken out of the milk, instead, what the industry does is to add lactase (the enzyme that digests lactose) to their product. The people that can't digest lactose lack the lactase enzyme, so, by adding it in their product, people without lactase can safely drink milk. In a sense, the lactose \"comes predigested\". Nutritionally, regular milk and lactose-free milk are exactly the same, the only difference will be that the lactose-free milk will taste sweeter because the lactose has already been broken down into its components, glucose and galactose."
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6mbfo0 | When a physical music album is manufactured, how do they put the tracks to the CD-R without getting them leaked by the people who work at the manufacturing company? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The companies have large security for all people going in and out of the facilities and track production very well to ensure all copies are accounted for. Before you enter and leave you go through airport like security detectors to see if you're carrying metal or cds out. How people would get out copies is pretty cool. You'd take one off the line and tag it as defective and trash it, as per the process for defective cds. Then after your shift you'd slyly sneak over and take it out of the trash. But now security. How to get it past an airport scanner? Be a redneck! You wear a large metal cowboy belt buckle, secretly hide the cd behind it, and when you go through security, they think it's just the big belt buckle. A huge amount of CDs that got stolen and released online were actually just from one single guy who worked in a North Carolina cd manufacturing plant named Dell Glover. A lot of this is recounted in what is roughly the seminal book on it right now by Stephan Witt called [How Music Got Free]( URL_0 ). It's a great read and ties back how the trends in music changed from physical to digital and the story of stealing pre-release cds is one of the driving forces",
"Also, commercial CDs are stamped, not burned. The original recording is provided once to create a stamping master. From then on, the original recording file is no longer needed, or available."
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6mbjd5 | What's the deal with videos and buffering? | Honestly, I remember at the dawn of the internet you could pause a video at the start, and the whole thing would (as I thought load) but I'm pretty sure is called buffering these days. Now...perfect example, I'm trying to watch the "Yes, God, Yes" vid and it keeps freezing. It's paused and stopped buffering about 15 seconds ahead. So, guess I'm curious what the legit reason is about why vids won't buffer all the way and have a pre-set mark they only load till. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Well, buffering is basically \"pre-loading\" the video ahead of where you are actually watching it at, which is nice if the connection is unstable or slow, because it allows you to keep watching the pre-loaded buffered video until the connection kicks back in and gains more ground. The problem is that, obviously, pre-loading a ton of video and creating a huge buffer is a traffic strain on servers when there are thousands/millions of people all trying to buffer thousands/millions of videos. So, lots of places put a limit on how far ahead a video can buffer, to avoid the strain on the servers. They'd rather have it stop and then start up again once you've caught up to the buffer, so they aren't buffering tons of video that you might never even get around to watching. That can add up to a lot of wasted bandwidth.",
"For Youtube the decision was based on massive amounts of data collected from user viewing habits. The largest driving factor is that, by a vast margin, people just didn't use the site that way. They clicked a link, and if the video didn't pop up and start playing quickly enough, they'd just click away. So they want to get you video, at whatever resolution they can, as quickly as possible. You're more likely to stay on the site if you don't have time to think about sites with other content. In order to ensure that the site operates as quickly as possible for the largest number of people (because they'll lose viewers otherwise), they break the video up in to tens/hundreds/thousands of chunks and monitor the speed at which you receive them. If you're downloading just fine, they can up the resolution. If it takes a bit too long to download that higher resolution, they can bump you back down. There are other side benefits like you/Youtube not using more bandwidth than necessary, the average user not storing more data than necessary, etc, but those are secondary benefits. The primary driver is providing as smooth an experience to an average user as is technically possible. eta: 1. You can still find plenty of sites that don't use this tech. 2. If you want to load a video for later, there are dozens of options for downloading for later. This also lets you keep the video beyond a device reboot. 3. It also lets youtube track viewership much easier and accurately. Now they can see precisely what you watched by seeing which chunks you downloaded. No weird JS tracking involved. 4. They don't want to load too far ahead, because download speeds vary. If you get stuck half way in to a video because your network got congested, you might leave the video."
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6mbn16 | How/why does the combination of Black, Yellow, Magenta, and Cyan be able to reproduce almost all colors in printed materials? | Technology | explainlikeimfive | {
"a_id": [
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"Your eyes only have three different types of cells that can detect color (assuming you aren't color-blind). One that responds best to blue light, one that responds best to green light, and one that responds best to red light. Your idea of color is based on how much each of these three cells responds to the light bouncing off an object. Because you only detect those three colors, your eyes can't tell the difference between something giving off yellow light and something giving off a mix of red and green light- the cells in your eyes will react the same in both cases. So with just three colors of light, you can trigger the cells in your eyes to react the same way they would with any visible color. So, if your eyes see red, blue, and green, where do cyan, yellow, and magenta come from? It's because ink absorbs color rather than giving it off. The cyan ink absorbs all the reds (so only the green and blue cones get triggered from the reflected light), the yellow ink absorbs all the blues, and the magenta ink absorbs all the greens. So this particular set of colors makes it simpler to figure out how much light of each color will get reflected back to your eyes and make the colors that you see."
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6mcag0 | How do video games (i.e Chess) change the AI depending on the level set (Easy, Medium, Hard)? | Technology | explainlikeimfive | {
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"The harder you set it, the more time the computer gives itself to examine every possible future situation -- what you might do next, then what it might do in response, then what you might do after that, etc. On low difficulty it won't look too far ahead.",
"Really depends upon the game. Some games take away certain features of the AI on lower dificulties. Others have the AI randomly make mistakes depending on difficulty. If you are playing a complex stategy game like Civ almost guaraneed the AI will start cheating on the higher difficulties and look at some of your stats even thogh it should not be able to see them."
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6mcp49 | why does RAM not have the same issue of limited write cycles that solid state drives do? | We're told that memory in solid state drives has a limit on how many times it can be written to before the sector becomes unusable. Firstly, how true of a statement is this? Secondly, how does RAM not have the same problems given that it's written to *a lot*. | Technology | explainlikeimfive | {
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"I'm going to try and ELI5 this, so *please* do not consider this a *technical* response. So, RAM has data written to it a lot, but it doesn't need to be *permanent*. That is, when you turn your computer off, and the RAM has no more power, you don't care what happens to the data. An SSD needs to retain that data without power. So, one way to think about this, is that you have to write the data *harder* (you know how I said non-technical?) Because you're doing that, it also wears out faster. Compare it to, say, writing on a whiteboard you can erase and reuse to writing on a piece of paper using a pencil and then using an eraser on that paper each time.",
"Two different types of storage. SSDs use a type of transistor called a Floating Gate MOSFET, which is really weird in the way it stores bits, but it works. However it seems that over time, these floating gate MOSFETs degrade in terms of their write capability. The big thing here to note is that transistors are not really designed to store a charge but seem to be able to for weird reasons. RAM uses capacitors to store charge. A capacitor essentially works like a little battery but with some significant differences, batteries store electrical energy in chemical form while capacitors have free floating electrons acting as a charge, and secondly, this makes capacitors very quick to charge and discharge, but they can't hold a lot of charge and cannot hold charge for long, depending on the capacitor, they are discharged within seconds or milliseconds. Anyways, RAM uses these capacitors, a charged capacitor = 1, an empty one = 0. I think the big part to look at here is that capacitors are designed to store charge while transistors were designed for other functions, but can store charge due to weird quantum mechanical consequences.",
"RAM uses a capacitor to store information. Imagine it is a bucket with a hole in it. To fill it you will need a constant stream of water. This little trickle of water doesn't damage at all, but you need a constant stream to make sure it's full. The water in this analogy is electricity. The RAM capacitor constantly drains of electricity. If it has electricity it's 1, if it doesn't it's 0. However if you lost power, all of it would quickly drain to zero. An SSD uses flash memory. Think of that like a painted sign. When you see it painted it's 0, when you see it unpainted it's 1. However that trickle of water isn't going to do anything to the paint when it's dry. You need to use a darn water jet cleaner to get the paint off, but the water jet peels off a piece of the sign every time it is used.. Likewise flash memory needs a relatively large amount of electricity to flip the state of the memory. This is enough electricity to damage the slot. Overtime this damage accumulates and you can't use it anymore.",
"I don't know too much about how RAM works, but I Googled it and found this: \"NAND flash stores the information by controlling the amount of electrons in a region called a “floating gate”. These electrons change the conductive properties of the memory cell (the gate voltage needed to turn the cell on and off), which in turn is used to store one or more bits of data in the cell. This is why the ability of the floating gate to hold a charge is critical to the cell’s ability to reliably store data.\" \"In digital electronics, a NAND gate (negative-AND) is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of the AND gate. NAND flash memory is a type of non-volatile storage technology that does not require power to retain data.\" I'm guessing that this only applies to NAND storage, which RAM doesn't use."
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6mdlyg | With Snapchat's new function: ''Our story'', how do snaps get regulated to prevent violence and nakedness appearing on the map? | Technology | explainlikeimfive | {
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"I am guessing that all the snaps that are going on the map for the general public get viewed by a Snapchat mod because I looked for boobs for hours and came up empty."
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6mdvml | How is it possible to store Bitcoin offline? | Bitcoin exists in so called wallets online and every user stores information about transactions. Being online based how can it be stored offline in order to protect it. How can it possibly become inacessible to hackers if it is an online currency? | Technology | explainlikeimfive | {
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"Bitcoin is basically one big, publicly viewable ledger book. It has many entries. Each entry says \"this coin (or part thereof) belongs to the person with the password XYZ\". What you actually store are not actual coins, but the password to access them. When you want to make a bitcoin transaction, your wallet (which holds a really complicated password you couldn't remember), be it in the cloud or offline, says \"yes hello this is my coin, please transfer it to the other person with the identifyer ZYX\". The problem with hackers is that when you use an online wallet, your really-complicated password *can* be retrieved if your wallet is unsafe. For example, if you use a cloud wallet, their database might be unsafe. Likewise, if you got it on your computer, a skilled hacker could access it. However, if you have the password on a usb stick or a piece of paper, there is no way that someone who is not near you (say, a Russian or Chinese hacker, wherever you are) can actually access it. However, this comes with the risk of losing whatever medium the password is on."
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6me9c9 | Facebook spam accounts that send you friend requests - who is making them and why? | Technology | explainlikeimfive | {
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"People pay for likes and promoting, so spam accounts are created and because they need to be believable they add random people, like a ton of stuff, but rarely have more than 1 or 2 photos.",
"I just had one that was an obvious scam. It was a hot \"American\" woman who had a shitty profile written in broken English. She said she worked at Western Union, which was an obvious red flag, and she was requesting only guys for friends. I did a reverse image search and found out that all of her pictures were ripped off from someone else. I linked them to her profile page, notified FB, and warned a of couple friends who friended her and liked a few of \"her\" photos. Her profile vanished. Essentially, the person behind the profile/scam befriends a gullible or lonely guy and asks for money. They usually promise something in exchange or pretend like they are in trouble and need help. Once they find a white knight, they will have their victim send money over via Western Union and the scammer will either disappear back to their internet cafe in Nigeria, or they will keep milking the victim for more. It's sad and pathetic, but they wouldn't be doing it if it didn't work."
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6me9gq | why researching fossils/ancient species is important? | I understand why researching space, energy, technology etc is so important to us, as they have many benefits to us; but what is the benefits of researching fossils and ancient species? | Technology | explainlikeimfive | {
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"text": [
"Studying ancient species gives us a better understanding of how species have developed over time. Understanding this gives us a better model to predict where they may go in the future, and a better ability to understand the relation between environmental factors and species evolution."
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6mfke2 | Why are computers unable to decode CAPTCHA? | Technology | explainlikeimfive | {
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"Google uses captchas to make you do their job. You might have seen text pics from actual books a lot recently. These texts are actually from books which Google's OCR couldn't understand. This was done for making digital books by Google. Also nowadays they tell you to find how many number plates, or sign boards, house number,etc. That is for Google Maps/Street view. Based on the highest frequency of a particular response, they assign the correct value. You hear people saying Google is awesome and all but then when you know Google, you see that they are next level awesome. They didn't pay for a single penny for getting this done.",
"You know a T is a T because it's a straight vertical line with a horizontal line on it's head. But a computer knows a T is a T because it's 01010100. If you show the T in such a way that there's no convenient letter code (because it's part of an image instead) and the computer actually has to look at and interperet a picture... that's really hard for machines, it's not something they were designed to do. Captchas make this even harder by distorting the text a little, so if the computer manages to learn what a T looks like and then you show it a skewed, rotated T, it may not find it. But the human eye, which is handles visual objects in 3D space and knows what \"kinda sidways T\" looks like, has no issue.",
"The human brain is absolutely amazing in its ability to filter out noise. Think of how you can pick out one person’s voice in a noisy crowd. Now compare that to your phone’s ability to translate your speech into text, and how if you’re muffled, talking too fast, or around even a few other talking people, your phone can’t handle it. Same with captcha. Our brains can pick out letters and numbers, even when they’re twisted and distorted, blurred, scribbled on, etc. Optical character recognition (OCR) is great technology, but it just isn’t advanced enough to identify noisy text the way we can.",
"They are able to! But it depends on the Captcha and how new it is. There have been several ways that people have taught computers how to solve them. One of which is a convolutional neural network. There's a cool [video by Computerphile about how this works]( URL_1 ). If it's confusing, watch their [convolution filters]( URL_0 ) video first. The tl:dr of how it works is this: the computer takes an image, then applies a bunch of different filters (like in Photoshop) to them. Then it takes the resulting pictures and does it again several times. Each time the filter makes the image shrink, and the end result is a series of images that are usually all white or all black, and that's interpreted as an answer. They train the computer how to do this by having it run through the process randomly and tell it when it's right or wrong. It has limits though. It's great for something like a single blurry word, but if the amount of words change, or if the ways in which the Captcha is made are wildly different, this method struggles. So if new Captchas are brought out, our method won't work without retraining. It's also fairly bad at the one where you have a series of pictures and you have to click all the ones that have a road sign (or whatever) in them. Why are Captchas hard to solve for computers? Well, in humans, it's already built in to us to abstract important information from a noisy image. Previously, we used computers to take very clean inputs that we already know are important, and process them. For instance, you'd punch 2+2 into the computer, and it wouldn't have to figure out if you'd actually typed a two, it's fed directly into the computer itself. The same thing with images. We don't ask Photoshop to interpret a picture's meaning, we ask it to make the picture more red, or more blurry, or whatever. Asking a computer to perform abstractions and figure out what's important information in something noisy is a tricky problem."
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6mgc6e | How do games in a single console generation go from looking one way to looking way better and performing better graphically on the same hardware? | ELI5: How do game devs make games like the original Resident Evil on PS1 with the blockier looking textures and characters to RE3, which looks better and plays better. Additional games like the original Uncharted vs. Uncharted 3 or The Last of Us are both on the same generation of consoles but TLoU and U3 look much better than Uncharted 1. If it is the same hardware, how does this happen? | Technology | explainlikeimfive | {
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"Often they're not taking full advantage of the hardware out of the gate, as they're still learning how to best apply the features of the technology. As an example, let's go back to the Sega Genesis. Here's a launch title for the platform, [alex kidd]( URL_0 ). Look at how boring and unmoving that background seems, for example, this looks like a slightly more colorful NES game. Then if you check out [The original Sonic, which came out three years later]( URL_1 ), check out THAT background. You've got a nice looking lake or ocean, clouds floating by, Sonic dips in front of and behind the foliage, the clouds float by... how does a game on the same hardware look so much better? Because they figured out a bunch of tricks they didn't know for Alex. The Genesis only supports 1 \"main\" and 2 \"background\" layers, but it also supports \"scrolling lines\" meaning you can make a whole row of pixels slide back and forth. The moutains that seem far, the water that seems closeish, and the clouds drifting by are all accomplished with this same trick. Clever application of one idea makes a SNAZZY effect. Another trick sonic pulls is in the water levels, where the water seems semitransparent. The Genesis couldn't *do* real transparency, so how did they make it happen? By changing the pallete halfway through drawing the picture to a darker set of paint-by-number colors, it makes half the picture look underwater. This is just one example, but every platform has tricks and clever applications of ideas that just aren't known when it's new. On modern hardware, clever application of pixel shaders and other effects are the same kinds of ideas."
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6miuns | Why can USB-C be the same plug on both ends, but regular USB-A always had to go from A to a different form factor? | Technology | explainlikeimfive | {
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"The names are a bit misleading. USB was designed to be super cheap so instead of having expensive chips that could automatically determine which is the device and which is the controller they made two plugs, type A and type B. It would always be type A in the controller and type B in the device. Then came smartphones and some manufacturer wanted to be able to connect USB devices to the smartphone device that also could charge and use data via the same port, and USB OtG (on the go) came to be. The phone could then act as both a controller and a device, if you plug in the right converter (usually a short cable that has a type B micro plug and a full-sized type A socket) it would automatically detect it and talk to the device as if it were a computer. And finally we have the new USB connector type that is symmetrical both in the connector itself (it doesn't matter which way you turn it, hooray!) and the cables, they can have the same connector on each end and automatically negotiate who is to act as the controller. Since this connector wasn't a type A or a type B, they named it type C and thus we have USB-C."
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6mj59b | Why do journalists and producers have to ask for permission to use a tweet or a video, but they don't ask for permission to (famous) people (politicans, rappers, etc.)? | Technology | explainlikeimfive | {
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"In America, depending on the state, there are different rules for dealing with public figures lives and private citizen's lives. A media outlet could report any publicly available tweet, but why would it?"
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6mjm9n | How is high-speed internet and on-demand television transmitted over what is basically just a thin copper wire? | Technology | explainlikeimfive | {
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"Radio, WiFi, Cable Internet all work on the same principles. Fiber internet works slightly differently. In the first 3 cases, the digital signal is converted to an analog one. Several frequencies are chosen as carrier waves (eg. on FM radio it's 2 frequencies near a target like 102.7Mhz). By varying the amplitudes, single sent frequency, or more commonly [the phase]( URL_0 ), you can encode one or more bits of digital information. On the receiving end, process is reverse, as the analog signal is decomposed into its component amplitude/frequency/phase differences an the digital value for that combination looked up. In fiber internet, the digital signal is sent directly as on/off pulses of light of a specific frequency. In all cases, the frequency dictates how much information can be sent per unit time. At the absolute bottom end of process, if there were no sources of noise, and you are sending a 1Hz signal (say a blinking light), you must wait at least 1 second to know if the light was on or off for that second. So you pick very high frequencies to maximize the data throughput and you send multiple concurrent signals at different frequencies. Each frequency can be tuned in by different receiver circuits (just like your radio tuner). This allows multiple channels of information to be sent at the same time."
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6mkgar | Why audiologists don't suggest bone conduction technology over cochlear implants? | brief context: I'm deaf in my right ear. The doctor suggests implants but I'm not eligible for them where I live. But bone conduction works for me, so I'm curious why I wasn't pointed towards the technology earlier. Is it something to do with the age of the tech, or just limited application? | Technology | explainlikeimfive | {
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"Because they do not fix the same problems. Cochlear implants replace the small bones of the inner ear when there is a major defect with them or they are missing all together. Bone conduction tech relies on the inner ear bones being mostly intact and the defects causing deafness being with the ear drum."
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6mlizm | how font designers can design for Japanese and Chinese, languages that both use millions of individual Chinese characters? | edit: I guess I had overestimated how many characters these languages use -- as many pointed out, it's only tens of thousands, at the most. Thanks for the great responses, though! | Technology | explainlikeimfive | {
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"It's a lot of work. In fact, Japanese and Chinese font files (ex ttf) are about 30 to 40 MB. Compare with an English font file which is about 0.5 MB.",
"CJK Type designer here. **1) Limited character set** As others have indicated, thankfully no one has to actually design millions of characters. Actual glyph coverage depends on the needs of the font. Let's look at Microsoft as a sample (including Latin & other symbol characters). Chinese (Trad / Simplified): 30,000 characters. Japanese: 24,000 characters Korean: 21,000 characters Now, the above includes a lot of glyphs that most people probably don't need. In the case of Korean, the most basic fonts can have just around 3,000 characters (just Hangul and Latin, no Hanja) and work for most scenarios. For Japanese, there’s 48 Katakana, 48 Hiragana, and about 3000 core Kanji (for literacy), which would cover a majority of scenarios. But for a company like Microsoft, a greater degree of support is necessary. **2) Accelerated and Semi-accelerated tools** In the case of Korean typefaces, there are tools that help expedite the development of Hangul characters. As Korean syllable glyphs are divided up into component pieces, one can instruct the tool on where to place those components and which variant of each component to use. For some fonts there are 40+ variants of each component! With this sort of tool, building can be faster. But it won't always work for a given situation and then the work has to be done by hand. In some Japanese foundries, there is something of an ‘toolkit’ that is used with examples of the different kinds of strokes necessary for Kanji. So the digitizer (more on that later) can just drag in the one that is appropriate for a given glyph. However, as each glyph is different, there’s still quite a bit of manual tweaking necessary from there. Part of the problem with Japanese and Chinese is, like with Korean, there’s significant manual adjustment of a given radical or stroke for every character. So even if a tool was able to at least ‘assemble’ the pieces into a given glyph, you’d have to make significant manual adjustments from there. **3) It takes an army** I heard a story from a friend of mine who visited a Chinese foundry. Designers would pull a Hanzi from a hat and that would be the character they have to produce. With an army of 30 people working on a single font, they’d churn through the characters until the font was complete. In one major Japanese foundry, there is a division of labor—“designers” draw the characters on paper, “digitizers” trace those drawings to digital representation, “production” takes the digital representations and produces actual fonts. All told, it is a significant operation involving a large group of people. It takes them a year to complete a single weight (say, the “Regular”) of a brand new font family. Producing these things is a TON OF WORK. A quick aside about Korean—given the existence of accelerated tools for production, these *can* be done faster than Japanese or Chinese fonts, but the best ones usually have manual edits and tweaking on an extensive number, if not all of the syllables. One Korean type designer I spoke to warned me about the use of accelerated tools—that the actual results from it are not that great. He, obviously, recommended doing everything by hand. **Basically:** 1) It may not be as many characters as you think it is 2) There are some tools for accelerating work, though a lot is still manual 3) Usually the work is done by a group of people, over a period of time, rather than by an individual. Got more questions? Feel free to ask!",
"There aren't millions of characters. To quote a BBC article: > Altogether there are over 50,000 characters, though a comprehensive modern dictionary will rarely list over 20,000 in use. An educated Chinese person will know about 8,000 characters, but you will only need about 2-3,000 to be able to read a newspaper.",
"I am Korean. While you asked for Japanese and Chinese, Korean fonts also requires Chinese characters and thus have similar problem with these languages. Usually, characters for these 3 languages are packed into one font, called CJK fonts. **First of all: do you know what fonts look like?: A list of characters** To put it simple, each font is a gigantic list of letters. If you input a letter, and there's no matching character in that list, it will not come out right; sometimes a blank will show, sometimes a different, typically weird looking letter will show. **Let's count the number of letters needed!: 50,000** Japanese also uses their own letters, which are around ~50. But they come in both smaller form and bigger form, which doubles the count. Still, the number is somewhat reasonable. Now for the main show! there are a lot of Chinese characters, as you already know. The problem gets even worse because China, Japan and Korea uses different kind of Chinese letter! Chinese uses the most simplified form (along with their own traditional form), Japanese uses less simplified form, and Korean uses the most complicated form. So you need 3~4 sets of Chinese characters. And Korean letters are a bit more complicated; the written Korean, Hangul, consist of ~30 components, and you are supposed to combine 2~6 of them into one letter. Which means there can be a lot of letters you can make, if there's no limitations! That's why font creators came up with a limit of their own. For Korean, they picked ~10,000 the most used letters in Korean, and put only those letters in the font. The same goes to the Chinese letters, although I don't know the number. I suppose you can google \"Chinese font character numbers\" for more detail. Let's say there are 10,000 for Korean and 4 set of Chinese character. It ends up with 50,000. Add the Japanese letters and it ends up with 50,100. Whatever, let's go with 50,000. By the way, that's the reason CJK fonts are way bigger than Alphabet-only fonts. Google is distributing Noto Sans series of fonts. If you're interested, look for Noto Sans English and Noto Sans CJK; and compare their size. CJK fonts are way, way bigger than English fonts. **How the fuck do they design letters?: Divide and Conquer** So, do the font designers design each and every letter in the font? All 50,000? The simple answer is, yes, they design every single letter in the font. But there is an easy way. Did I mention that Korean consist of components? Similar principle goes for Chinese, although they are way crazier than Korean. There is ~10 components in Chinese, but in the most complicated case, Chinese characters are combined of 1~30 components. But, still, they are made of components. **Which means you can set a design standard**. Once you make a design standard, you can use them as building blocks for more complicated letters. Like LEGO! When you combine each components into a letter, components might slightly change their shapes. Still, you can make more design standards for them, and use them for the letter. **Even easier way!!: Don't design them at all** There's yet another much easier way to deal with this problem. Buy a cheap font license, and recycle them. Let's say you're designing a font specifically for Japanese and Japanese only. You don't need 50,000 letters; you only need 100 for Japanese letters and 10,000 for Japanese-Chinese letters. If you give up on the rest you can cut off 80% of the work! And that's how it's typically done. There are a lot of Chinese-only, Japanese-only or Korean-only fonts.",
"Amateur font designer here. Did you know an LGC (Latin-Greek-Cyrillic) font, like the one you're reading right now, can also include hundreds or thousands of characters? Most widely used LGC fonts cover all 3 of those alphabets. There are a lot of variations on most of the letters with various accents, and of course those numbers are doubled with capitals and lower case. Different weights and styles must be designed (e.g. italic, condensed, bold; some professional fonts have over half a dozen weights with 50+ combinations, like Extra Light Expanded Italic). Also many fonts have extra characters that are ligatures (two letters stuck together), the most common being ff, fl, and fi. (The font I'm typing in on my mobile, Dosis, has ligatures for 2 of those 3.) Unlike CJK (Chinese-Japanese-Korean) fonts, which are generally monospaced, LGC fonts must be kerned, meaning each and every pair of characters (including punctuation and both letter cases) must be manually assigned a value for how close together they should be in order to \"look right\". This has to be done by a human eye because a machine has no idea what \"looks right\". TL:DR; It's a lot of work to design a font for a language like Chinese, but it should be appreciated that \"a ton of work\" is also normal for fonts used for English. That's why many quality fonts are *not* free.",
"I'll talk Simplified Chinese, since that's what I know. The Chinese government has created [a list of commonly used characters]( URL_1 ). It contains 8105 characters; characters outside of this list are going to be very rare (and even some characters within the list are rare, like 玃, the name of a particular kind of ape, or 𫚭, which I can't even find in my dictionary). 8105 is of course a much larger number than the 52 that we need for English (26 upper case, 26 lower case) that needs to be encoded. However, to *design* them, less work needs to be done. Chinese characters can be broken down into parts that are often repeated across similar words. For example, consider the word for shine 照. In the top of that character, you can see other component characters: the one for sun 日 in the top left, knife 刀 in the top right, and mouth 口 in the middle right. The bottom is four dots, a component historically derived for the character for fire 火. In all four of these cases, we can reuse these component parts in other characters that use them; the font designer only needs to design such parts once, needing only to resize them and move them around. In our example, other places we can use these four component characters are: 日 is on the left side of time 时, 刀 is on the bottom of cleave or chop 劈, 口 is on the left of eat 吃, and the modified 火 is on the bottom of hot 热, among many, many others. (For further reading, look up \"Chinese radicals.\") It's also worth noting that font design in English is not just designing the 52 characters (and miscellaneous punctuation). It also requires logic that governs what happens when two particular characters are placed together (ligatures) - for example, [this image]( URL_0 ) shows what might happen if a font designer thinks that f and i should be rendered differently when they are together, as in fi: these are called ligatures. An extreme case happens in Arabic, where each letter has a different beginning, middle, and ending form. Chinese does not have such complexities that it needs to encode in its font (Chinese has a square symbol for each character, including punctuation, and these characters look the same no matter what's before or after it), which mitigates the file size and design requirements. And there's the logic about \"where it's legal to break to a new line\" - it's OK to break a line after a dash or hyphen, but not after an apostrophe (unless there's a space after it). The first example below is perfectly readable but the second one is odd: it's a new- fangled idea it' s a new-fangled idea Again, Chinese has more simple rules regarding this, though there are still rules (you can't break right before a period, for example). But this is just a reminder that fonts are not just strings of character designs, there is also logic behind them that needs to be included. In practice, Chinese fonts also include the basic English alphabet because it's so prevalent (and indeed in informal contexts some English letters are used alongside Chinese characters), and also there are use-cases where people will need obscure characters not in the list of 8105 commonly used characters, so font designers will need to include some such characters, too. So it is indeed far more work to create a Chinese font than an English one. It's just probably not quite as bad as you think it is. By the way, I'm pretty sure there are similar official lists of \"commonly used characters\" in Taiwanese-style Traditional Chinese, Hong Kong-style Traditional Chinese, and Japanese (and maybe even Singapore-style Simplified Chinese? I'm not too sure). But the difference between these writing systems is a different topic. (Disclaimer: I'm not a font designer, so the details might be slightly off. However, I am a Chinese speaker, albeit not quite a fluent one, and more importantly a Unicode enthusiast, if that's a thing, so the overall ideas should be correct. Anyone with more knowledge on the subject, feel free to elaborate on anything or point out anything that's incorrect.)",
"Chinese Han text and Japanese Kanji text use a set of strokes that form the millions of words. So the font is based on how each stroke would look rather than the resulting word.",
"To summarize: * There aren't millions, at most 50,000 total. * Of those, only about 20,000 are in modern use in any capacity. * Of those, you only need about 3,000 to be literate, 8,000 or so if you're educated. * Further, the vast majority of characters are made up of a few hundred (maybe less) common sub-components, with unique components being very rare. Font designers can ~~easily~~ at least somewhat reuse these. * A comprehensive font *is* expensive, big, and hard to make! Most CJK fonts only cover the few thousand most common characters.",
"I am a reporter at Quartz and a little while ago wrote a [very in-depth article]( URL_0 ) on the process of creating Chinese fonts, by interviewing typographers in Taiwan. I'll answer your questions with my own knowledge and some quotes from that piece. The short answer is that it takes a lot of work, and a lot of time. As I wrote in the piece: > An experienced designer, working alone, can in under six months create a new font that covers dozens of Western languages. For a single Chinese font it takes a team of several designers at least two years. But while there are many more glyphs—units of a typeface—needed for Chinese and Japanese, the number does not go to the \"millions.\" > The default set for English-language fonts contains about 230 glyphs. A font that covers all of the Latin scripts—that’s over 100 languages plus extra symbols—contains 840 glyphs, according to Březina. The simplified version of Chinese, used primarily in mainland China, requires nearly 7,000 glyphs. For traditional Chinese, used in Taiwan and Hong Kong, the number of glyphs is 13,053. It's important to know two things about Chinese characters to get a better understanding of how this works: * Characters share a large number of \"strokes\"—the same motion or parts of characters are common across dozens of characters. * Even so, each character has slightly different aesthetics, and \"balance\" is of critical importance. So even if the strokes are the same, a character may need to be tweaked (there are many graphical examples showing this in my piece) The short answer is that CJK font design is much more of a team effort, while Western fonts can be designed chiefly by a single person or small number of people. There is much more detail in my story, I encourage you to read it, but let me know if y'all have other questions. Edit: Please be aware that there is a huge amount of misinformation in this thread. For one thing, the numbers of characters being thrown around randomly are based on _number of Chinese characters that have ever existed_, not on numbers of glyphs needed to create a font. As I say above, a simplified Chinese font needs close to 7,000 glyphs, although there are by some accounts 100,000 total Chinese characters. Second, as u/sajatypeworks rightly points out, while characters do normally share many strokes, that does not help much in terms of completing a character for a typeface. Each stroke or radical appears slightly differently in the context of a given character, so automated tools cannot do much more than collect the relevant strokes or radicals for a designer to manipulate. As you can see from some of the images in my piece, collecting these strokes and radicals is hardly the end of the process, which is why the font has to go through dozens of iterations before completion.",
"The other two didn't really give satusfying answers imo so let me help you out. Chinese characters are made up of radical, which are like little symbols with basic meanings. For example, 他 (ta) or 她 (ta) both mean he or she respectively (but pronounced the same. However, they differ in how they are read. Notice in both characters there is that second radical that looks like a jaw, that's 也 (ye) which means always. And when we look into the first radical in both words we find that the first radical is 人 (ren) and 女 (nw); ren means person and nw means women. So the charcters for he and she directly translate to always person or always women. Of course, it's not like this all the time. But what I hope you can see is that there are little building blocks in the language that make it easier to write. I assume they just make the radicals in the font which would be used to make the rest of the hundreds of characters.",
"At least for Japanese, many fonts you find online do not have every single kanji character. Most only have a couple hundred to one thousand.",
"Many characters share radicals kind of similar to prefixes and suffixes in English. So characters with 针, 镇, 铹 can share one \"side\", and 忆，钇，艺 can share other \"side\". The cool thing about many Chinese characters is that these radicals are reused to help define a character, so even though there are many different individual characters they use repeating ones to help define what the character is referring to. This happens to help lower the \"cost\" of design and also learning the written language slightly easier.",
"IAMA worker and business owner in Japan who does a lot of graphic design in both Japanese and English. (I've designed stuff from flyers to websites to large building mounted signs... though this is not my main job.) Whereas in English we have unlimited fonts to choose from, in Japanese that list is considerably smaller. We have about 700 fonts available for English and only about 30 for Japanese. All of these fonts came free with the computers or were added as free fonts later on. When we want 'cool' Japanese fonts (that include chinese characters).. for example a 'hand-writing' font, we are left with only 3 options: 1) Spend more than 1000 dollars on a super hi-quality font. The cost derives from the sheer manpower or man-hours consumed to produce it, as outlined by many other responses on this thread. 2) Get a 'limited' font that only has the top 1000 or so characters. This might be free, but we might have to 're-write' the sign or flyer to just include the available characters. 3) Make our own very limited font. This is only for flyer headlines or signs. You have someone write what you want. Then, you don't actually make that into a font but rather just keep it as a rasterized picture. In sum, it is hard, it is a pain in the ass, and it makes 'cool' graphic design in Japan considerably more difficult.",
"I've heard that Japanese graphic designers are always surprised at the abundance of fonts available in English (and other languages that use the same alphabet), and especially how many of them are free to use. Making a font is a bigger commitment in Japan, so there's less available, and apparently most fonts that are made are quite strict about IP and getting paid for their use.",
"There are different kinds of (brush) strokes that make up all the characters, so you can build a font that way",
"they draw out all of the few thousand characters they want to include (not millions). It's not as intensive as it sounds, as many components of the characters are repeated. Like the simplified chinese character for building 楼 is made up of the characters for wood+rice+woman 木米女",
"The company I work for has a website which can be switched between multiple languages. The code has a setting which tells the website which of the multiple language files to use. Each file contains all of the phrases used by the website For example if we had a paragraph which says 'my name is Steve' each file would have a line with a key of paragraph.welcome. In each separate language file the translation of 'my name is Steve' is paired to that key. Then whenever that text is used we use the key rather than the text itself. Now the tricky part is the part your question was mostly asking about. In Chinese, Arabic or English 'hello my name is Steve' could be three lines long. This means we have to design screens in a flexible way meaning the parts can grow without overlapping neighboring content. We do this using responsive design (which we also use for display content across all screen sizes). I mentioned Arabic and Chinese because these languages are written in different orientations. Thankfully on the web and in computers Chinese is written in the standard left to right. Arabic on the other hand is written right to left. We have special settings that know which languages are written right to left and when one of these languages is selected the website's mirror image is then displayed. This means in Arabic, the whole website is displayed from right to left",
"Late to the party, but I am friends with a Senior Computer Scientist at Adobe who literal wrote the book on digitizing CJKV characters. If people wanted I could ask him to do a casual AMA.",
"If I may ask a related question... How do you type 10,000+ characters on a ~200 key keyboard? Genuinely curious. It can't be as hard as the old hold ALT and enter ACSII code method that was usable on DOS machines.",
"I have no experience with typeface design, but I did study Chinese and work in China for several years. I can give you a quick 101 on how a font for all 20,000-50,000 Chinese characters could be developed with little more work than a Romantic font. Radicals Chinese is pictographic, or at least it retains its basic pictographic structure. The character for 'person' is 人 (pronounced 'ren'). Draw a line across the top third of that character, add a little circle at the top, and you can see how it's a pictogram of a person. Over generations, the pictographic essence of the language has been simplified into what we see now, so you'd have to look back at the traditional or ancient characters to see the evidence for most, but it's there. While 人 is a character on it's own, it is also extremely important to the rest of the language because it is a 'radical;' that is, a character which can be transposed into another character to form a new word. There are about 200 of these radicals in standard Chinese. Take 仐 (pronounced 'san'). If you look closely at the character, you'll see 人 - slightly stretched so that the resulting character still fits the same square space as every other character - on top. In this case I have no idea what function it serves. The word means 'umbrella' so I assume it's being used out of context - it simply looks like a shelter so it's not serving any purpose related to its meaning. In some cases, radicals also carry their symbolism into the word they construct, but I'm not familiar enough with the language to elaborate on this. If we jump ahead and look at some of the crazier characters with like 25 strokes, one like 儺 (\"nuo,\" which means 'rich') you'll see the radical for 人 again, except this time it's modified even further. Look to the left and you'll see 亻. 亻 is a modified version of 人, tilted slightly to one side with one stroke aligned on the vertical axis and stretched, so that it can fit the more complicated characters. To design a text, I suspect the artist works their aesthetic magic and first creates the 200 radicals and their variants (most have fewer variants than 人). Once they do that, creating the whole dictionary would simply be a matter of putting the radicals together into the words they construct. Because Chinese characters are so ordered, a spatial formula assigning the radicals to their place in each character could be created once, and used to systematically generate the full language from each newly designed set of radicals. At all levels, the written language corresponds to some kind of ruleset, and using those rules an artist could create a typeface without having to manually design all 20-50,000 characters. Source: Laowei who studied Chinese for a few years while working in Beijing.",
"Let say you want to build a lot of houses, but you don't want to design them one by one. So what you do this to design different styles of columns, beams, walls, etc. finally you assemble those structures into different houses. In building Chinese fonts, font designers would select some basic characters to build up the framework of the font. In Chinese calligraphy, the character 永 [eternity] is used to test out the decsign of the font, for it has the eight basic strokes of the Chinese writing system. After that the designers would assemble (using font design programmes) other characters using these designed strokes. Finally they must fine tune each of the generated characters (about 10000 of them) to arrive at a consistent design style. The character 永 URL_0 Common component in different characters URL_2 Fine tuning of different characters URL_1",
"I have actually built a Chinese font for my work. Traditionally if you are making a cool font that is only for flashy sales stuff you tend just to paint each word or only make a font file that holds about 100 chars. If you want to make a brand new font for reading then yer, 3000 chars will be needed for most things but you can tell if a char is missing, 6000+ will cover 99% of use cases on the web. I have Worked in Chinese UX design for 6 years and only once we used a 3d party font ( noto sans ) everywhere else we let the computers built on font do the work (microsoft yahe for windows and pingfang for mac) because asking the user to download such a beast is really undesirable. You can checkout URL_0 for examples of Chinese fonts",
"For Korean, there's only 40 or so individual letters: ㄱㄴㄷㄹㅁㅂㅅㅇㅈㅊㅋㅌㅍㅎㅏㅑㅓㅕㅜㅠㅗㅛㅡㅣㅐㅒ ㅔ Each consonant looks different depending on which part of the word it's in: 가 그 각 옦 긔 괵 So you probably only need to make a couple hundred characters and then combine them automatically, then adjust the weird ones manually.",
"Is this a good place to ask why all Chinese manufacturers seem to use the same English alphabet font? Is it the only English font on their computers? What is its name? You see it in manuals, on boxes, printed on PCBs, it's everywhere. Its an Avec Serif font, it looks like a scratchy Times New Roman It's really distinctive because no one in the West uses it, probably because it's not very nice to look at."
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6mlsbm | How do metal detectors not detect themselves? | Technology | explainlikeimfive | {
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"the easiest way to think of it is like a flash camera. so the flash is a bulb with a casing that only allows the light to leave in one direction. It then reflects back into the lens and a picture is formed of everything that reflected light in that direction within a set time. In our scenario we are creating a magnetic field and using [magnetic shielding]( URL_0 ) we build a casing which guides the field in one direction. it then interacts with any metal (creating it's own different magnetic field) and we have a sense that looks for any magnetic fields which do not match what we sent out."
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6mlymv | During deep-space fly-bys, satellite reconnaissance etc. what's with all the composite images, false colors, and "recreations"? Why can't NASA/the ESA just take a photo? | Technology | explainlikeimfive | {
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"When youre 37 times further from the sun everything can look pretty dim and grey. The cameras on these craft also don't always image the same wavelength band as human eyeballs. The original photographs are therefore often quite washed out or at incorrect wavelengths. Space agencies do release those photos for more academic purposes, but the media outreach people like to put together composite images with increased or modified color contrast to show what those objects would look like to human eyes in better lighting conditions. False color photos are also often used to show elevation or composition changes on a planets surface that would otherwise be a dull grey sphere. Elevation and composition on earth is easy to see because of the climate zones and biosphere changes, but Ganymede has neither."
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6mm8au | How did Satoshi Nakamoto, the creator of Bitcoin, stay anonymous? | He would even post regularly on bitcoin forums and published a lot of code. Were absolutely no identifying details found (stylometry for text or code, metadata, etc.)? | Technology | explainlikeimfive | {
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"He took extra care to always communicate over anonymous lines, such as Tor, and avoided giving any information that could connect his real identify with his alterego. Seeing as he went so far to do this, he probably is also a person who takes privacy and anonymity seriously in his personal life too, so there probably aren't a lot of ways to cross reference his personal identify with his online one. For example, he may have avoid social media like Facebook or have been very restrictive in his Facebook profile so that it's very difficult or impossible to find similarities between his Facebook activities and his Bitcoin related activities. Finally, Satoshi Nakamoto has effectively stopped all communication. I've been out of the loop for a couple years now, but the last communication I remember from him was his Twitter confirming that the \"real Satoshi Nakamoto\" that was being reported on at the time, was not the same person."
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6mmkir | Why are software development tools freely available yet photo and video editing software prices so high? | Granted there are paid tools, IDE's and features but an average Joe can get started building software for nothing. Whereas if you wanted to start learning video production or photo editing there is often no free tier (sometimes a short trial) and then you are stuck with purchasing software for more than its worth to an amateur with features you don't understand. How did these markets get so different? | Technology | explainlikeimfive | {
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"There are free options for photo editing as well. GIMP is widely popular. Why are there no free ones? Because programmers that write code for you without asking for anything in return are angels. And beggers shouldn't be whiners.",
"For a few reasons: 1. software developers themselves are capable of creating software development tools. This impact is hard to quantify, but...no doubt a big deal. This then can mean that a person can both know the users (because they are one) and build a solution. At the very least for the class of applications you're talking about you'd need some level of product management right out of the gate, which is a significant barrier to start-up of an OSS project which often gets off the ground by the heroics of one or a few individuals. 2. There are a good number of open source products in your space. They just don't have the same widespread use. GIMP comes to mind for photo editing, Blender for video. 3. Users of these software are not often able to build, compile and debug the software. OSS software is _often_ challenging to setup and get configured. Software geeks are accustomed to that, not graphic designers. 4. Software engineers aren't as frequently exchanging complex files in complex formats. Source code is pretty standardized - it's not like a PSD file, or a working file for a video. It's far more important to have tool standardization for video and images than it is for software. In software the source code repository is the common point, in video it's the file and it's format.",
"It actually boils down to a business reason. Microsoft (for example) wants cool software to exist for windows. If you give developers the best tools to develop software on windows, more people will use those tools. Users will then be forced to buy Windows to run that software so Microsoft makes money. The same is true now for every operating system. Arguably windows became so popular because of this very fact. In the first versions of windows the developer tools actually came with a full version of windows so the developer didn't even have to pay for the operating system which enticed them even more to develop for windows. Essentially dev tools are secondary to operating system sales. Companies like Adobe sell photo shop because it is their primary product. If they gave it away for free they wouldn't be able to make money."
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6mnweq | Why do download websites allow fake download buttons/viruses to be on their website? | Seems a little counterintuitive | Technology | explainlikeimfive | {
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"They're ads that the companies with the downloads are paying for. Many sites with the fake download buttons are either illegal or not the main route of downloading things so they see less traffic and have to find alternate methods of financial gain.",
"Because download sites aren't making any money from you downloading free stuff from them. They make money with advertising, and that's what those fake download buttons are.",
"Cost per Click and Cost per Impression are two very important elements when determining pricing for advertising. Given that the website is for downloading, it's actually more profitable for the webmaster to use dubious ad placement to get higher click rate on ads. The website is likely more or less bullshit and the majority of the money comes from ad revenue from those very ads that you are talking about."
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