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hp0zgv | Data Collection Methodology | URL_0 The link above talks about data collection regarding TikTok. Is someone able to explain what the original Reddit user is saying from the line "they set up a local proxy server on your device" onwards? | Technology | explainlikeimfive | {
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"By setting up a proxy server on the local device, they are basically allowed to listen to web requests from other applications. It would be like giving someone the key to your mailbox so they can look for coupons. Sure, they say they're not going to loot the birthday cards, but can you really trust them?"
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hp3xlk | how one installs a operating system on a computer without anything on it alteady | Technology | explainlikeimfive | {
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"the short answer is that there's already something on the computer. the motherboard has a program called BIOS that does really low level stuff (like load the OS from the drive). An installer for the OS is on a disk or flash drive and the BIOS will load that if there isn't an operating system installed already.",
"When a computer starts up, it has a few simple steps that it performs automatically, no matter what, without any programming. Those steps are basically, 1. Find a disk, 2. Run whatever is on the disk. On a computer with an operating system already installed, in step 1, the computer finds the internal disk. On a computer with no operating system installed, you have to provide the disk. That will be in the form of a CD, DVD or thumb drive. You put that disk in, then turn on the computer. The computer will find that disk, and run whatever is on it. Assuming you put the right stuff on that disk, the program on that disk will write an operating system to the internal hard drive of the computer, so the next time the computer reboots, it will load the operating system from the internal disk."
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hp5zcn | I never really understood SSD/HDD IOPS | Like the title, can someone provide an easy to understand explanation of what IOPS are? I understand it's the number of "operations" a drive can do per second or something like that? But I cannot for the life of me relate it to speed When does IOPS become a bottleneck vs when does NAND Speed become the bottleneck | Technology | explainlikeimfive | {
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"IOPS is used to measure a drive’s random IO performance, as opposed to throughput, or MB/s, being used to measure sequential IO performance. Random IO refers to the starting address of each IO being random. HDDs have a lot of trouble dealing with this type of IO pattern, but SSDs do not. So for applications where random IO performance is important, people look for SSDs that can give them high IOPS."
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hpbol2 | How exactly do photographs work? | How can you freeze an image of reality onto a tangible surface? | Technology | explainlikeimfive | {
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"There are certain chemicals that are sensitive to light. When exposed to light they change colors (specifically get darker). To make a picture with film, you first have transparent plastic that is coated with a chemical that burns depending on how much light hits it. When you expose that film to light for a fraction of a second the parts that were brighter in the image turn darker on the film. And the parts of the image that are darker reflect less light and so the film remains more transparent. You then process that film thru chemicals that freeze the light reacting chemicals and prevent them from continuing to react. Now you have a sheet of semi transparent film that is an inverted image of the image you wanted to capture. If you project light thru that film. You can project it onto a sheet of paper that is coated with similar chemicals that react to light (the parts exposed to more light will darken more). If you do this for a few seconds and then use chemicals to freeze the light reacting chemicals again then you will get an image that is an inverse of the inverse of the original image, in other words it looks like the image you took. This explanation implies a black and white photo. But color film works similarly it just has has chemical that react to different colors of light when they darken. Digital cameras are kinda similar. The lens, shutter, and aperture can all work the same as film except instead of projecting the image onto a sheet of film it projects it onto a square of a bunch of light sensors in a grid. Each sensor measures exactly how much light hit that spot and records it on a defined scale, for this example from a range from 0 to 255. 0 if it saw no light at all, 255 if it saw the maximum amount of light it is able to measure. For most cameras, each pixel has a filter on it that only allows it to see either blue, red or green light. When you group the data from 3 (or usually 4 with an extra green) pixels that are all right next to each other you can get a value for that tiny square of the image that is recorded like: red = 200, green = 40, blue = 220, which would be a pixel that is a shade of purple. And when you add all of the millions of light sensors’ data to gather you can get a list of what every dot in the grid (a pixel). Some image file formats are literally a list from left to right for each row of pixels of how much light each recorded. So when a display needs to show the image it just shows a light with that color hue at that brightness in the location that the sensor recorded it.",
"If you close your eye and open them and quickly realise them you see an image. A camera does this but the image is picked up by either chemicals that react with light or a sensor that detects lots of tiny dots of light. These are then turned into the image by either a tiny computer or chemical development.",
"When you paint, your interpreting the light coming into your eyes as colors and your making a representation of that light on a canvas or whatever. A camera is similar, but instead of your hand and paintbrush making a representation of the light, a digital sensor will record the color and brightness values of the light hitting the sensor and recording it to a file"
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hpe95n | What is sn API? And the differences between API and API REST? | Hello everyone, i'm getting into code recently and i have heard these terms a lot. Can someone explain what are they? And if you have a good source or tutorials to learn API, you can leave the link in the answer. PD: URL_0 has free courses and certifications about API, but i don't know ,if they are good and if would be easy to follow with zero knowledge. Thank you!!! | Technology | explainlikeimfive | {
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"An API is a way of making data available to applications. Say you have a database of useful information. Say, weather. You can't just send the database to anyone who wants it. Apart from practical implications, it's constantly being updated. So you host the database on a public server, and you build an API so that people can access it. This usually means that you set up HTTP routes that return the requested data. For example, you might setup ' URL_0 ' which would grab a five day forecast for London. That's one example. You can also make your own 'private' API. It's common these days to have a web app with a JavaScript front end (the pages the user sees) populated with data from a database. Facebook is a prime example. To enable the front end to get the data, you code an API. So your user might go to ' URL_1 '. In the background, the frontend hits 'api/users/4652577'. The backend (the database and it's controlling code) does something like \"SELECT user WHERE id=4652577\" and then returns that user's data to the frontend where it can be displayed however the designer wants.",
"An API is an Application Programming Interface, its a general term for a library of programs/functions to interact with an application directly via other code. For example a 3D Design software may have an API which allows a python program to send calls to build blocks or fillet sharp corners. If you want to interact with an application at the code level, you should become familiar with that application's specific API. If an application does not have an API, automating tasks within that application is much more difficult with direct support from the application developer. REST APIs (REpresentation State Transfer) are a specific type of API with a common layout used for applications that would like to communicate over the internet or other networks. They use HTML requests like GET, PUT, POST, and DELETE to fetch, send, or modify data. For example GitHub has a REST API so a program running on your computer could login (with your credentials) to upload or download changes to a git repository."
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hpfmi8 | What are carbon nanotubes and why are they such a big deal in so many fields? | Technology | explainlikeimfive | {
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"Carbon nanotubes are like microscopic straws made of carbon. You can't see them, because they are on the atomic scale. You can confirm their presence with things like Raman spectroscopy. Some people think we'll be able to make the world's strongest rope with it. Some people think we'll be able to make better solar panels with them. Some people even think they'll be useful for drug delivery in medicine. I personally think they'll end up being used in very small quantities for research specific type applications. So no space elevator!"
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hpfq5s | How do sleep trackers actually lead to better sleep? | I understand what sleep tracking is. What I don't understand is how the data it provides actually helps you sleep better. Every time I think about buying one, I feel like it's just gonna tell me "you're not sleeping well" and I won't know what to do with that info. | Technology | explainlikeimfive | {
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"Sleep tracking apps and features don’t help you sleep better because they can’t put you in bed and make you fall asleep, same as they can’t make you get out of bed in time. Those things are on you. But provided you can enact behavior changes like these, even if just slightly, then sleep tracking tech can give you information to help you make better decisions about what to change. For example, a year or so ago I moved to a different place and started sleeping on a different mattress. I slept more or less the same amount of time and at similar times, but with the help of sleep tracking app I could determine my quality of sleep had indeed worsened significantly. So I got a different mattress and saw improvements. When I started sleeping with a partner, I also noticed changes that the app helped solidify. In short: sleep tracking doesn’t solve anything but it helps you solve things."
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hpiruc | Are websites just like files saved on a server somewhere far away? | Windows specifies drive letters for everything connected (like C:\ for the main storage or E:\ for a flash drive) and I was wondering if web servers are kinda like "Drive HTTP" then a folder with no name on the root directory and then inside that nameless folder is millions of files with .COM extensions. | Technology | explainlikeimfive | {
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"In a way yes, though websites are a bit different. Firstly you typically don't have millions of sites stored on one server, indeed even single sites like reddit are often spread across many servers to load balance all the users connecting to them. Your idea of a website just being a folder is in fact very accurate for how websites work, or at least used to. The URL portion after the domain number was originally intended as a file path and many simplier servers still treat it that way. However over time *dynamic* content (provided by scripts) has become the norm. You see it used to be if you wanted a webpage you'd create the HTML in notepad and upload it to your webserver as an HTML file. But that meant it was static - the page looked the same to anyone and if you wanted something to change you'd have to edit the file. Things like web forums aren't really possible like that and so scripting became popular. Initially scripts just stood in for files, so when you tried to download `/forum.php` the server would execute the script instead which would generate a custom HTML file to download. Then more advanced scripting came along that treated the entire URL as a script parameter, so on a site like reddit you can see each 'folder' in the path is actually a parameter in what page you want the sites programming to load or generate for you."
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hpjg0a | Recently, many scandals have come out about various apps secretly reading their users’ clipboards. Why is that such a bad thing? Oftentimes many people don’t have anything of value copied, so why is the clipboard specifically such a dire development? | Technology | explainlikeimfive | {
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"Some password manager apps use the clipboard so you can paste in your user name/password on a login screen. Monitoring the clipboard makes it very easy to collect a bunch of login credentials."
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hpn3wf | how Google claims not to 'sell' your data, so what does Google do to give data to others, and what data is being shown to them? | Technology | explainlikeimfive | {
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"Google does not directly give your data to anyone. They don't want to- access to your data is the secret sauce that makes Google ads more valuable than ads from other places. Instead, companies can come to them with an advertisement targeted towards men in their 30s in the American Southeast that like baking, and they can make sure to show that advertisement to that group of people. Since they're only showing the ads to the people most likely to respond to them, they get more responses and so Google gets more money from the advertiser, while being able to sell ad spots for other demographics to other companies.",
"Google uses your information to decide what ads to show to you. An advertiser tells Google that they want their ads shown to people who are likely to use their products, and google uses all the data it has collected about you to work out whether that means you. This is how they make money off your info without selling that info to other people. Then my multilayer add blocking system just drops those connections to a google ad server, and I don't see anything anyway, which is a bonus.",
"you can also see what information Google has on you that are \"targetable\" by online advertisers at URL_0",
"Imagine your friend Eve coming to you and asking you to tell all your friends who are fans of beer that they should try that new Heineken that was just released because she thought it was super awesome and she doesn't want them to miss it. You know exactly that your friends Alice and Bob would be super interested to hear about this, as they not only like beer, but you know they also have shown interest in Heineken before. You then tell Alice and Bob about the beer and they go buy it at their local store. In this example Eve (advertiser) reached who she wanted, but does not know who Alice and Bob (Audience) are, because you (Google/Facebook) only shared with her that you told \"two of your friends who like beer and Heineken\"."
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hpndl2 | How is a new video game sometimes "ready to play" when less than half the game is downloaded? | Technology | explainlikeimfive | {
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"Some games are packaged in a way that gives you what you need to start the game first. The game is a bunch of separate files. There’s sound, music, levels, character models etc. if the game is set up for it, you can download the title screen and the first level, and start playing before the final boss is downloaded.",
"There are huge segments of files that are needed for optimal experience, but aren't needed for *an* experience. For example, high quality images are a nice to have, but if you get low quality ones downloaded first, you can do them faster and allow access to them while you wait for the larger, better versions to come through. You can also cut out content you're not likely to see at first from the initial download, since you're likely to need them later rather than sooner. Those credit animations? Put them on delay. Maps that you only access after collecting achievements? Don't need them to start. Custom high level objects? You can use a default skin for the first run and the user probably won't even notice. By the time it maters, the game has already had hours to download content, meaning it's likely completed.",
"Well to use a simple example imagine if a game has 100 levels. Itll download the materials for levels 1-50 knowing you wont get to 51 in that play session."
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hpnxhw | why does traditional charcoal/wood fire ovens produce better pizzas than my home oven? It’s just heat isn’t it? | Technology | explainlikeimfive | {
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"Its not just heat though. Those wood fired/charcoal ovens are HOT (like 700-800 degrees) and the pizza sits directly on the surface of the oven rather than suspended from a rack. This means it gets a very crisp crust, very quickly, with a healthy amount of char to boot. Not to mention the smoke (there's not much of it, but it's there) from charcoal/wood just makes everything taste better.",
"Traditional brick pizza ovens are operated at higher temperatures than home ovens can reach. Additionally, the bottom of the pizza is in contact with hot brick, rather than steel, which transfers heat at different rates. To make the perfect pizza, you need the right temperatures so that the dough is cooked but not dried out at the same time the toppings are well cooked.",
"Because unless you put your oven on the cleaning setting it will never get as hot as a real pizza oven."
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hpvlnd | Why do remote controls still work but weirdly when the battery is low? | What I mean by weirdly, is for example the AC remote sometimes wont work unless I stand directly in front of the AC, and then I get new batteries and it works from anywhere as usual. Or for example, when my wireless mouse is low on battery, it starts skipping across the screen. Or my wireless backlit keyboard, I normally keep the backlighting on purple because I like that colour, but when the battery is low is instead becomes like a weak pink for some reason until I charge it up. | Technology | explainlikeimfive | {
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"Remotes, or IR remotes in particular (by far the most common type) work by sending a very short sequence of infrared light, which is picked up by an infrared receiver on the TV/AC/etc. It's conceptually extremely similar to if you and a friend were on the other side of a field at night, and gave eachother directions with a flashlight in Morse Code (with each letter telling you to do something different. e.g. A means walk forwards, B means walk backwards, C means turn left, etc). What happens when a flashlight is almost out of batteries? The light gets dimmer. Same deal here - the IR lightbulb isn't getting enough juice to function properly so it's a lot dimmer, meaning you need to be closer for the IR receiver to pick it up. Your wireless keyboard and mouse are probably either 2.4/5Ghz wireless or bluetooth But similar idea here. Your mouse probably starts skipping because it is getting insufficient power to power the laser light and/or operate the radio properly. Your keyboard likely changes colors as the RGB LEDs (basically one red, one green, and one blue LED in one small package) start losing power and get dimmer, although purple to pink is kinda weird because \"true\" purple doesn't have any green in it, but pink does so if anything I'd expect pink to weak purple, with the G LED getting lost along the way instead of suddenly kicking in.",
"The the battery is low, the device can't produce as much current to power the IR emitters/radio transmitters. Also, low state batteries fade faster, they produce more current when first switched on than in the following seconds. The first effect explains the range. The fade effect may explain your mouse. It has enough current to keep the count of where it is, but the power fades during the radio transmission. The computer sees that as a bad radio packet, and ignores it. After a while, a packet gets through and the mouse skips.",
"The devices are designed to work best when the battery level ( voltage ) is within certain ranges. In the case of the remote, they work with infrared LEDs that blink in different patterns according to the button pushed, like Morse code. When the battery is low the led doesn't light up as strong. We can't see the infrared light, but it works the same as flashlight LEDs, low battery = dim light. You may be able to verify this for yourself by looking at the front of the remote through your phone camera app. In the case of the wireless mouse, it is probably a similar thing, but using radio waves instead, you may find that placing the mouse closer to the receiver will get you slightly better responsiveness, until the battery depletes further. It is also possible that the tracking LEDs themselves suffer the same problem as the AC remote LEDs do - in which case being closer to the receiver won't help. For the backlight: multicolored lights like that are typically created by using separate Red, Green and Blue LEDs, the blue and green LEDs need more power to light up than the red, so as power gets lower those individual LEDs get dimmer first and you are left with increasingly reddish hues ( assuming there is any red in the original color). My first time trying to ELY5, sorry if I miss the mark :)"
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hpxd1z | Libraries in programming. what do they help in? | I am trying to learn JS and I just can't understand libraries. What are different libraries like node.js or p5.js used for? Can we code without using any library? What are pros & cons of libraries? | Technology | explainlikeimfive | {
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"Libraries are just pieces of reusable code. Think copy/pasting a chunk of code into your program, but better. So they help with pretty much everything. You can code without using them, but you'll find that you have to do a lot of work lots of other people did before. Libraries are used to provide about anything. Functions for dealing with encryption, interfaces to web services, creating a better UI, etc.",
"Libraries are just bits of code that have already been written by someone else and packaged in a way that other people can also use. There isn't really a general answer for \"what do they help with\" because they're just code, they help with whatever task they are programmed to help with. You could code without them (well some basic ones might be needed depending on the programming language), but there's not really much point in doing that if there is a good library that does what you need it to do. The con could be that because it's code written by someone else, you don't know exactly how it works. Depending on the language and how it's distributed you might not even be able to look at the code for it. Maybe it's not an exact fit for what you need, or it has loads of bugs. So it's worth evaluating on a case by case basis whether you should use it or not. This answer is in terms of programming in general. I don't know JS or anything about the particular libraries you've mentioned.",
"Basically, libraries contain a bunch of pre-coded objects and files that you can use. This is useful because they allow you to use specific functions, objects, or other stuff without having to code them from scratch."
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hq1tnx | what makes a computer slow down? | i absolutely don’t understand computers, so please bear with me, and please use words that i’d understand ✌️ (or at least explain what they mean) basically, i’m getting a new Mac because my current one is extremely slow, and i’d like to not make my new one slow, if that makes sense. so, what should i do to avoid making it slow and have it run fast for a couple of years? any tips? | Technology | explainlikeimfive | {
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"Three things can make a computer slow: 1) having too many programs open at once, 2) having more files than you need, and 3) old technology. My 2012 MacBook Pro, which I am using right now, used to be slow because it had a hard disk drive. Upgrading to a solid-state drive has helped a lot, and was cheaper than buying a whole new Mac.",
"Assuming your old mac didn’t have a mechanical hard drive, what makes it slow is running too many applications or poorly written applications which use too much CPU or memory at the same time. My 2013 macbook pro runs just as fast as the day I bought it... granted the battery only lasts about an hour. If your old machine was a PC with Windows then all bets are off. Could have been malware running in the background. Google Chrome is also a memory hog. To be clear, there’s nothing in the hardware that would make it slower over time unless it’s really dirty and throttling speed due to heat buildup."
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hq2dcg | if video/pictures are stored as a collection of pixels, how is audio stored? | Technology | explainlikeimfive | {
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"Samples of the amount of the deflection of the microphone's diaphragm over regular points in time. So a microphone is pretty much the same thing as a speaker, except optimized differently. You can push on a speaker's cone, or pull on it. Pushing it positive values, pulling is negative ones. You measure the position 44100 times per second, and store the number."
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hq2s0z | Why did it take so much time to introduce dark theme on the most common platforms? And why do companies act like it was such a difficult task to realize it? | I mean, when they add dark theme it seems to be the biggest revolution in history, instead of saying "we are sorry it took 10 years to accomplish this pathetic color change" | Technology | explainlikeimfive | {
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"Software developer here. TL;DR: Realistically dark mode is just much more complicated than it seems on the surface, and there are many reasons why. First is your design and how easy it is to translate to dark mode. Sure, you can go ahead and ctrl+f all whites to blacks and vice versa, but the result will be much like a negative photograph - it just looks and feels weird. Shadows meant for a light app will feel out of place on a dark background. You may find your brand colours do not fit at all in a dark theme. The list goes on, but to build a usable dark mode many things need to be slightly \"redesigned\" to fit a dark theme. And this is not a one-time task: having dark mode available also means that any new features will need to also be designed to work in it, which increases design work needed to ship new things. From a software development perspective, implementing dark mode requires the overall theming of your app to be setup well, ideally such that you can change a single line of code to e.g. change the accent or background color across your entire app. This is pretty much a prerequisite for being able to have dark mode (the user clicks a button and the theme changes). Traditionally it has been quite rare that you would need to change your theme colors, which also means that many apps and websites are built without any such fancy theming system in place - colors are just hardcoded and other more important features have been prioritised. Or perhaps development of the app was started some time ago, when the entire idea of users being able to change the colors according to their preferences was not very trendy. In any case, if your app has not been built with a theming system in place, the effort required to implement such a system now – in a large project – might be many weeks of work and involves slightly editing almost every single file in your project. Often development/design resources are limited and implementing dark mode would then mean that some other work will be delayed for however long it takes. In the end, dark mode is a purely quality-of-life update for an arguably niche user group and it can be very hard to convince your sales team that the value of adding dark mode is higher than all of the other things waiting on your roadmap. EDITs for clarity.",
"Very specific example: email readers... if I write an email to you using my light mode and use my brand colors, which are a dark purple and a burnt orange for the purposes of this discussion, for my signature, how should it render on your dark-mode email reader? How does the software know which colors to replace those purples and oranges with so as to preserve the integrity of the original message, while also allowing you to comfortably read it with the settings you have in place? All this to say... So much of the web and apps are dependent on people to create content who are not the designers/developers that things like this take forever to think of, research, create a plan for, code, and test in order to create a usable product.",
"3 major things: 1) Not every graphical item you see on the screen has easily configurable color controls. Web sites are generally 100% controlled by the developer, but for applications on your computer, a lot of the widgets drawn on the screen are set by the OS designers (Microsoft or Apple). Without them making changes to their OS and the widgets the OS provides, developers either don't have control, or have to go through every single widget and replace it with custom widgets where they were previously using standard OS widgets. 2) Not every graphical item you see on the screen is a drawn widget, some of them are pictures, JPGs or PNGs that are the colors that they are, and without extensive photoshoping couldn't be converted. Or something might be designed with transparency, that works really well as long as the background is white or some other light color, and looks terrible if the background is grey or some other dark color. 3) There's more to \"dark mode\" than just inverting all the colors. Both Windows and Mac OS already have the ability to just invert all the colors on the screen (on macOS, go to Preferences - > Accesssibility - > Display - > Invert Colors, for windows Settings - > Ease of Access - > and either Color Filters or High Contrast). But if you go and invert the colors on your screen and then use your computer for a bit you'll find it looks kind of ugly in a lot of places and definitely doesn't look like the dark modes of your major apps. A lot of thought, time and effort goes into choosing color schemes and picking out the right set of colors that go together. To do dark mode properly, you have to do all of that same work, for an entirely different color palette. Doing that work takes time, and even if it's just one person, that person isn't doing other things while they're doing that work. So for every software developer, it's also a question of is it worth not doing X so that I can instead have \"dark mode\" for my application.",
"1: 1000s of bugs need resource before enhancements unfortunately. 2: It's not as simple as changing black to white, years of coding standard changes has introduced technical debt and complexity. 3: Dark mode is more a usability thing than a cosmetic one, with the rise of mobile - more and more people are using platforms in places that are not the traditional workstation, lighting is usually more ambient and bright backgrounds cause eye-strain and sleep issues. There's a lot more to it than that of course, but those are some of the reasons we've happened upon.",
"Imagine you have a white button up shirt. You need to go attend a funeral in the morning, which means you need to wear black. You can't afford a new shirt so you decide to paint your shirt black. Easy right? Well, let's say you found out you had a wedding right after the funeral and needed to wear white? You decided to be clever and paint the inside of the shirt black and make it reversable. So you have a \"dark mode\" and \"light mode\". You then find out the problem isn't as simple as you thought when you notice that when your shirt is reversed, the buttons are backwards, your collar looks weird, the logo is missing, and the tag is popping out. This is the same with software, it's not as simple as \"painting\" things black. Some parts need to be redesigned in order to make them interchangeable, as well as making sure they don't look \"weird\"",
"Product owner here: dark mode costs a lot more time and effort to implement than you might expect. So for me there was always another feature that brought more value for less effort. (Untill it didn't, and than you introduce dark mode)",
"Because it WAS difficult. I had a guy mention to me that my design didn’t work on his dark-mode pet project. I pointed out that our branding doesn’t support dark mode, and all our art and colors will look bad that way. He didn’t complain... because turns out when you work with professionals they understand that projects like that take months and involve coordination with quite a few people. There’s never unlimited time or money - being good at your job means understanding what to prioritize. It’s only ever armchair critics like OP who think it’s easy.",
"There were a lot of dark theme websites in the 1990's made by regular people. They looked very amateur. To look professional you needed to go with what all the big businesses were doing which was plain and boring. Its just taken a long time to get out of that mindset that dark themes are low effort",
"Why is dark mode such a big deal anyways?",
"You make something. You invest a lot of time in it. Learning all the how to do this before you ever get to the level of \"I think I can make one better myself\" It takes weeks or months, years even to perfect it. You control everything about it. It is your baby. It reflects you, your preferences, your style, your methodology. Everything is the way you feel works best for you. Decisions were made based on previous decisions, each building on the one before in order to maintain cohesion and allow the thing to function. One day you sit back and say \"I wonder if this can help anyone else out there, surely there is someone that thinks like me and will see the value and purpose of this.\" Finally after many years/tears you release it to the world. It worked beautifully in your home, but in someone else's home it is a little off. They ask if you can make it work for them too. Some one else doesn't think exactly like you and so they don't understand intuitively how to make it do the thing you said it is amazing at, so you tweak it, make it so out in front that it hides the cool ways it can be tweaked to be perfect for everyone. Someone else this and someone else that, but it is all so that they can use the thing you made. You do it because you find that you kinda of get a kick out of simply being able to help. Years later, it finally works for everyone. Now the only thing left is to create a new function to change to colors of everything. It's the only thing anyone is complaining about now because you made everything else work. Some people noticed your work fixing problems and some didn't. Some people complained about things that were fixed 11 months ago and waSte your time making you think the problem is back, all because they were too lazy to get the new one. But that is the past, everything is done. This color change doesn't make your thing do different stuff, or fix anything that didn't work which is why it took years to get here. Yeah, it could have been done sooner, but then the actual broken things would stay broken longer. But the people who couldn't do what you did are getting loud, and you are so very tired on the complaints about color. So you make a very big deal about this change. A whole new version, from 1.9.3 to 2.0. You want everyone to see this change... It's the only way to get them to be quite.",
"Just to add a little. Many apps are also hybrid (single codebase running on web/iOS/Android), where the entire app runs inside a webview (browser window hidden inside a normal native app that looks like any other app). For Android straight forward theme changing abilities were only recently added to webviews (and are still in beta I believe, though fully native theming has been supported for a while), for iOS WebView theming is relatively easy. (This obviously depends on your implementation of themes eg. Using media queries, switching stylesheets, etc) Also considerations for design / feature toggling: an app may not have a coherently consistent style throughout the app, and depending on how big the app is many features may have toggles associated with them, so you may run into a situation where having a toggle prevents you from taking a step back and having a more holistic theme (introducing tech debt), as you may need to keep the standard theme (light mode) unchanged.",
"Not sure of you mean why it took Google/Apple (actual platforms) so long or common apps. I'll try answer both. Google/Apple: Google has actually has supported a night mode for years, it was added when car platforms were added to Android. Not sure why it took so long to being it to phones. My best guess why it was added to phones on both platforms last year is that there were no exciting new features to present so this was a flashy, very visible one they could do. Common apps: most common apps have been around for a while, they have a lot of legacy code, many probably don't have a decent design system set up so instead of bringing in some complementary colors and call it a day, they need to go over each screen in the app and update the colors. That's a lot of tedious work for many engineers. For the ones that are monetized with ads there might also be concerns how ads perform in that new color schema so they might want to experiment/roll out slowly to be able to make changes. Furthermore, a dark theme is not a feature as such, you can't sell it as \"premium version only\" so it might be expensive to put resources towards it without seeing a clear return. So why did it happen? Google/Apple put marketing behind it and sold it as something that should just be considered normal. That puts pressure on every developer to implement it as it would make your app look outdated, behind and not going with what's expected on those platforms.",
"Working with the product of one of the big companies, we've been going at it for at least 6 months in order to enable dark mode for our app. It starts designing the new chunk of code that would allow the rest of the system understand the theming requests in a common way since every microsystem is independent from each other. Building this backbone took about three months to get it up and running from design based on existing architecture and conversations across teams to get everybody aligned and agree on the design since not everybody thinks the same and there's always going to be that one person that doesn't quite like the design. Implementing it the design took about a week. About three months up to here. Then we needed to come up with conventions for naming different areas of UX to make it easier for everybody to understand, things like `buttonBackground` refers to the background color of a button and not the color of the login animation. This took a couple of weeks since there were way less conversations needed and the implementation was pretty simple. About 3.5 months up to here. Then we got to the fun part of mapping all of UX to the new conventions, this took an initial effort on the development area coming up with mappings that would sound OK and wouldn't have conflicts. You'd need to scavenge through all of the code looking for things that our UI, this in itself can be quite a burden if the code is not well organized. This part of work was purely documentations of the proposed design since it'd need approval from the design team for such mappings, this part took some more time just because people are busy and it can take some time getting everybody to read/agree with the designs. About 4 months up to here. From here we've had to be pushing changes ok each one of our sub systems to actually used the selected naming conventions for UX theming. This required lots of different _small_ changes that needed to be reviewed by the teams that actually wrote that code initially just to make sure everything would work. This, of course, would trigger lots of questions that have already been answered but not everyone has heard about earlier regarding previous designs. Theming is now real thing to when someone else is touching the code that you wrote. About 6 months up to here. Up to here there hasn't really been any visual change so far, now we need to make the places where our product renders use the backbone to tell the entire system \"_I want `buttonBackground` to be `yellow`_\" in case some dark mode flag is enabled by the user. And that's after designing and implementing the UX to enable such a flag. Fun stuff... Edit: typo"
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hq3py3 | Why do game developers store assets outside the map rather than just spawn them when needed? | Hi everyone, I've been watching the 'Boundary Break' series on YouTube focusing on taking the camera outside maps on video games (in this case, Zelda: OOT) to see what we otherwise wouldn't be able to, and I've noticed a common theme. Developers seem to treat the digital worlds and assets they create as though they were dealing with physical items in physical space. Let me give an example. Say in Zelda, you are entering a room in which there's a boss fight, but the boss hasn't appeared yet. It's a very long (as in physically long) boss. But rather than it just spawning in when it needs to, the boss is already there, stored under the map. You can't see it, but it's in the room. Not only that, but in OOT, the boss is folded up as though there wasn't enough space for it down where it's stored! Why is this? Why is the boss folded when there must be unlimited space to store assets if the developers want it, and why do they need to store them out of sight at all? This is a game - can't they just spawn them when necessary? Could it be something to do with having one chance on entry into the room to load all assets without interrupting play? | Technology | explainlikeimfive | {
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"I can’t give an exact answer here but I can tell you that in most engines, loading an asset into a scene takes a *lot* longer than moving it around the scene. It usually involves at least one round trip to the hard drive, some kind of deserialization turning it from a file into a live asset, and whatever other routines need to be run to get it ready and in the scene. Whereas changing its location is as simple as changing a few numbers. I’m not sure about why they’re sometimes “folded up”, though. Possibly something to do with culling (not rending objects that aren’t visible to improve performance).",
"> can't they just spawn them when necessary? Sure they can, but it might damage the experience. Not all the assets (in-game objects, visual things) are loaded into memory at the same time, it takes too much space. Instead a system is set up to dynamically load the necessary information when needed based on a set of rules. If for example the player is on one side of the world map and a unique building is on the other side then that building's information isn't stored in active memory. As the player gets closer and gets the chance to see it then the building will at some point be loaded. There may even be several steps along the way where a very low quality version is loaded first so the building can be seen from a great distance but with very low resolution textures and reduced complexity of the model. Now if the player is in a boss room and there are parts of the boss which are not yet visible, at the point where they need to become visible the system needs to find that data on the disk and load it into memory before it can start to render the boss. Doing all that can mean jerks as the system hesitates trying to get the information, and even \"pop-in\" as the data isn't ready before the boss is supposed to become visible and it just appears out of thin air as the system catches up. Instead the boss can be stored outside the room in space the player is never supposed to see. That way their overarching system of loading assets will load the boss into memory and be ready to display it whenever it is needed. You could of course add some script to pre-load the assets before the fight starts and not have the boss be anywhere until it appears, but that would require a special solution to something which is already handled with broad rules.",
"The main reason is that spawning an object is an expensive operation for the engine. As a result, spawning a large object all of a sudden can cause the game to freeze for a few frames as it tries to get the object fully loaded. Instead what we can do is load everything we need way earlier and hide it until we need it. So while ur watching the cutscene of you entering the boss room, its smooth and doesnt stutter when the boss appears."
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hq4419 | how was old school film editing done? Like, aside from the veg basic two pieces of film taped together on reel, I cannot get my head around how titles, music, dissolves, VFX etc were done without computers. | Technology | explainlikeimfive | {
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"Imagine that you've got two projectors focused on the same screen. Now imagine that you dim the bulb in one projector while lighting up the other one. Now you dim the second while bringing up the first. Voila, you've just faded from one scene to another. Now imagine that you block off part of the image from one projector as you unblock the same part of the image from the other. That's how a wipe is done. This is the basic operation of a device called the optical printer. Basically an optical printer is like a projector shining into a camera. The unexposed film in the camera is synchronized frame by frame with the film in the projector. Using prisms and semi-reflective mirrors, multiple projector heads can be combined in the optical printer. A matte is a black image on glass or film to prevent certain parts of the negative from being exposed. The negative is rewound and the reverse matte (clear where the original was black, black where it was clear) is run, along with the new action. This exposes the previously protected film and protects the previously exposed film. This is how they do wipes, and if the matte moves, then it is called a travelling matte. Travelling mattes are how the folks at ILM combined models of X-Wings with paintings of far-away moons.",
"The two most common methods were rotoscoping, where you projected a film onto frosted glass and then animated over it. But most special effects were literally just that, Special effects. For example the teleporter effect in stars trek was made by filming aluminum powder being dropped in front of a slow motion camera and then sandwiching all three film strips together to fade from one scene to the backdrop."
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hq5454 | How does dubbed anime sync up with the camera angles so nicely? | I can’t find a better way to word it in title so I’ll try to give a more thorough explanation here. I’ve noticed dubbed (let’s use English just as an example) anime and subbed (Japanese) anime audio syncs up almost perfectly, but the sentences sound much longer to say in subbed. For example the character could be saying something like “Our game is tomorrow, let’s win this!” And both for subbed and dubbed the camera angle stays on that character, even though in English the sentence wouldn’t be as long. Does that make sense? It probably doesn’t make sense | Technology | explainlikeimfive | {
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"Because you only speak your language you wouldn't notice how different the sentences are, what the subtitles read is not word for word from the original dubs, they do change quite a bit to fit them, but the end result of conversation or context ends up being similar enough most of the time. Biggest difference I know is Goku in Japanese is a proper country bumpkin who is quite selfish in his actions, training and fighting at whatever cost, but in Engligh he is more like superman."
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hq75pw | Why are computer loading or installing timelines so intermittent in giving a correct time? | Technology | explainlikeimfive | {
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"Installations are complicated procedures that often involve retrieving, decompressing, and writing a large amount of files. The speed of these three steps will vary relative to each other from one computer to the next. Trying to estimate how long the decompression will take before it starts is futile. Even in the same computer, other processes might be starving the system resources if you tried the procedure at different times. Overall time estimates in installers are typically shit forced in there by someone who doesn't understand this despite it inevitably being explained to them multiple times."
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hq7njg | How can advanced film cameras record so much data (IMAX, 8K, 4K) and the finished film only totalling to a couple of gigabytes in retail, when just my phone alone gets up to 3GB just recording 20 minutes on 1080p? | Technology | explainlikeimfive | {
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"Filmmaker here! So yes cinema cameras record MASSIVE files, all for the purpose of saving as much data and information in the image as possible. That doesn't just mean resolution, but dynamic range (brightness from the blackest blacks to the whitest whites for example), bitrate (the amount of data that is controlled per second), etc. What this then creates are files that are large but can be manipulated in post when editing. For example, if I were to record an interview with someone, my camera would record roughly 16 gigabytes per minute. While this is still pretty small for a cinema camera, it is much much larger than consumers would generally want for videos. The reason that a BluRay can be from 50-100 gigabytes total then for the final film is due to compression (specifically H.265 for 4K BluRays). A basic understanding of how it works is when compressing the master version, the encoder takes a look at the adjacent frames and sees what is different about them. If a certain part of the frame didn't change, then it says okay I don't need to store this information, just reference this other frame for that point. It also groups together certain sectors of pixels and takes the average and \"approximates\" what that group of pixels should look like. All of this out together can transform a final master copy of the film which is hundreds of gigabytes to terabytes into a final version that while large at 50-100 gigabytes, is much more consumer friendly and much easier for playback. The reason that streaming and files you may find online are much smaller is because those are then compressed even more, whether that be through lowering the resolution or more likely the bitrate (again the amount of data that is being processed per second) of the video. As an added bonus, the film's you see in theaters are generally a separate version created from the master copy of the film. These can be hundreds of gigabytes to multi terabytes due to the circumstances of wanting the highest quality possible!",
"What retail media has 4k/8k movies that are only a few gigabytes? Bluray are 25Gb to 50Gb. And if you're talking about online downloads then they are compressed. Your phone doesnt do much compression when recording because the cpu is not fast enough",
"Professional cameras record many terabytes of data. That data is then re-encoded to fit however much space they have on the media they are distributing it. Which is tens of gigabytes in most cases."
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hqcl9h | How do you touchscreens distinguish between human skin and other materials, such as clothing? Was it intensional? | Technology | explainlikeimfive | {
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"There are wires embedded in the glass. If it's a material that can cause a short (skin is conductive) it will determine x-y co-ordinates from where the short occurs. Old-school touch-screens were pressure sensor activated but those didn't work as well. If you put a piece of wire on the tip of your glove you can still use the modern screens.",
"Not really intentional as much as it is convenient that skin and clothes happen to be pretty different electrially. Speaking. Really what it's measuring is change in an electric property called the dielectric constant (how well molecules align with electric fields). The capacitive sensor is tuned to react when fingers are nearby. In principle it could be tuned to detect different things, like wood, plastic, or metal, and capacitive sending isn't limited to just fingers. Studfinders work this way for example to find wood studs behind walls. Also strictly speaking mostly fingers are just water, and capacitive touch screens are just sensing that water rather than your skin, and don't actually need physical contact. Depending on how the sensor is tuned you may be able to get a press to register without actually touching, or may have to press down harder so that your finger squishes a bit and more of it is closer to the sensor. Now with older touchscreens like resistive they usually work with just pressure and finger deformation. A rigid object like a pen tip will only contact at one spot, while a deformable object like a finger can trigger multiple spots which can help with filtering out accidental bumps, but a softer object like clothes won't have enough pressure behind it to activate the sensor.",
"touch screens don't sense pressure actually, they sense electric current. our bodies generate a small amount of current and the screens sense that current to tell that we're touching it. electrically insulating material like most clothing blocks this, but some materials conduct it, which is how some styluses and those phone-safe gloves work.",
"Modern touch screens measure capacitance of the different parts of the screen to determine if your finger is over it. Different material have different capacitance, this is a property related to electrical conductivity as well so simply speaking if something conducts electricity it will trigger the touch screen. So your flesh, water and metal will be sensed but not air or cotton. The system was designed to distinguish between a human finger and air, the other materials were just accidental. For example they would have liked to ignore water but not cotton for example."
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hqd647 | Question about how code turns into everything coded (computer screen, games, webpages, etc.) | Technology | explainlikeimfive | {
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"At the very basic level, the computer screen has a bunch of tiny lights on it which the computer code tells to turn on and off in order to produce pictures. Different lights are differently coloured (each pixel has a red, green and blue light) in order to create colour pictures. Everything beyond that is more elaborate and abstract ways of telling the computer how to figure out which lights should be on and which lights should be off at a given point in time.",
"Since whole-topic overviews are not allowed, r/learnprogramming might know better."
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hqey20 | when people get sentenced to the death penalty, why does it take so many years (sometimes decades) before the penalty is carried out? | Technology | explainlikeimfive | {
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"There are a lot of oppertunities to appeal the conviction. We might find new evidence in the case, new evidence might show that the methods used in the old cases does not work as intended, new cases might show that the interpretation of the laws might have been faulty, etc. Executing the death penalty early will deny the convicted the chance of overturning their death sentence. Before the UK abolished the death sentence they did have a policy to execute it within just a few days of the verdict. However after several instances of wrongfull convictions, including one murder that got three different people hang for the same crime, they abolished the death sentence. There have also been a lot of Americans sentenced to death only to walk out decades later as free men.",
"you cannot undo a death sentence. falsely imprisoning a person sucks, but at least you can let them go free when you find out they werent actually guilty and compensate them a bit and while it's not quite a \"no harm, no foul\" situation, it works. but if you kill someone and then find out that they were indeed innocent (which already has happened a few times), it's too late to do anything about it. so you have to wait out the whole appeal-process, which also is more lengthy because you want to make sure even more than normal that you got the right person. which is why pretty much all civilized countries abolished the death sentence in the past century."
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hqftn2 | I’ve just read that “Vinyl like” super Solid State Drives could one day make Hard Disk Drives completely obsolete? | Apparently using 3D QLC NAND technology, “wafer SSD’s” could totally revolutionise the way we make Drives - What on earth is 3D QLC NAND and what is a wafer SSD please? | Technology | explainlikeimfive | {
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"Old news by now I think? * NAND - A type of flash memory. Not really important for ELI5 purposes. * QLC - Quad Level Cell. Each cell of the device can store 4 bits in it. Initially we had 1 bit, then 2, then 3, now we're up to 4. The more you try to squeeze into each cell the more delicate the whole thing gets, but we've learned to compensate for that very well so it actually works quite nicely for consumer use. So if you had 256 million cells before, you'd have 256 MB. With QLC you have 1024MB instead. * 3D - Fancy way of saying \"we stack memory in sheets on top of each other\". So if you have room for 1 TB, and stack 4 layers on top of each other, you can have 4 TB now. But the TL;DR of all of this is \"we're inventing more and more ways of squeezing more data into the same amount of space, and doing it cheaper\".",
"NAND flash is the basic type of technology: small silicon cells that are capable of storing bits without requiring a constant power source. I don't know the specific difference to NOR flash, but pretty much all SD cards, SSDs and so on use NAND. Think of each of these cells like a little measuring cup, with markers for how many electrons are in there. If you write something in there, you put the right amount of electrons into the cup, and reading measures how much is in there. xLC refers to how many markers there are: Single Level Cells (SLC) have just two markers, one for 0 and one for 1. Multi Leve Cells (MLC) have four markers, so they can distinguish 00, 01, 10 and 11 - two bits. QLC has 16 markers in total, allowing it to store 4 bits in a single cell. Fewer markers makes it easier and faster to read and write, which improves performance and makes them last longer. Which is why SLC is traditionally used for high performance applications, whereas TLC and QLC were more for cheap consumer devices. However, TLC and QLC have become good enough that SLC is now a niche product at best. Now a wafer is a disk of silicon, which is the stuff from which computer chips are made. They look like [this]( URL_0 ) once the circuits have been printed on them. Normally, the chips are broken from the wafer (cleaved) after this process and packaged into the finished product. A waver SSD however would skip that final step. It's just a giant piece of silicon soldered onto a circuit board. It wouldn't be a revolution, it would just be a little bit cheaper to produce because they could skip the cleaving and packaging in the factory."
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hqggmw | Why do some app’s features change depending on the device it’s used on? | For example: why is Microsoft one note able to have colourized text blocks in the pc versions but not only is it not an option on iPhone’s one note app, but it even omits the colourized text if added from a different device. | Technology | explainlikeimfive | {
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"The most common two reasons would be: 1) Phone limitation: With all phones being different, some are able to handle and display features better than others. If my phone can't show multi colours, then it doesn't matter if the app offers it, it just won't be possible. 2) Company restrictions: In a case like this, Microsoft probably acknowledges that a lot of it's users will be using iPhones, however it's preference will be towards their own customers, i.e those on PC using a Windows OS. If you're using their device, then they're happy to give you a much better product. If you are using it on a competitors device, then they will give you the basic functionality to use the product, but not as much stuff as you would if you used it on their own device."
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hqh9su | Why does the volume for the same show vary so much when you’re watching it? | For example, the speaking parts will be quieter than the music or the intro. So I have to keep adjusting the volume while watching a show. It’s so obnoxious! | Technology | explainlikeimfive | {
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"text": [
"Badly designed, or your speakers/headphones might be optimised for different things which are more common in music than speech."
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hqikcs | Why do SIM cards need to have programs running on them? | Most sim card run JavaCard, a subset of Java. They also have the capability to have their software updated by the network provider. Why do they need this? | Technology | explainlikeimfive | {
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"Because that's what allows the SIM to interface with the carrier network. It needs the ability to update so carriers can push new data to the SIM because they're constantly updating their own network software."
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hqj57x | In video game piracy, how does cracking work? | I've heard of video games which have antipiracy software such as Denuvo. But how does cracking work and how does antipiracy software make it harder to crack those games? | Technology | explainlikeimfive | {
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"It really depends on the game in question - there are all manner of security systems in software. In the olden days, validation of the software's legitimacy was done by validating a license key. The games could be cracked either by developing a keygen (an algorithm that would generate a key the game would accept as legitimate) or by altering the code to accept any key as legitimate (removing/altering the algorithm that checked to see if the key was legit). Now, most games have some sort of DRM that checks in with a central server to validate that the copy is legitimate. Sometimes this can be bypassed by altering your machines host file so it can't connect to the validation server (an the software allows itself to continue to run in cases where it cannot validate) or again by altering the code to automatically return a valid response without actually checking in with the server. It is always a game of cat and mouse, though. Each time DRM is cracked, developers create new, better DRM. DRM will _always_ get cracked eventually, because so long as you know there is a key for the lock, it is only a matter of time before you figure out how to replicate the key."
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hqk4wo | how do wireless wifi ‘repeaters’ actually work? | So I’ve seen some wireless wifi extenders or whatever they’re called online and it doesn’t make sense to me how they work so if you needed to extend your wifi, it would be most likely because for example a part of your house doesn’t get as much signal, therefore slow wifi, right? And since you want more signal you’d put the extender in the part that has slow wifi - but then what does it do? if the extender just wirelessly connects to the wifi from where it’s placed... wouldn’t it just be limited by the bad signal, thus defeating the purpose of the extender? | Technology | explainlikeimfive | {
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"A repeater has a higher gain antenna than your phone or laptop or whatever, so it can pick up weaker signals better. But yes if you put a repeater at a bad spot it wont do much. So you should put it just before the bad spot where it can still pick up a good signal and then is able to send a stronger signal to the bad spot vs just trying to connect to your main router which is much further away."
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hqrqzm | Is it possible to string multiple computers together to increase performance? | Or do the parts bottleneck each other? I thought supercomputers were just multiple computers strung together; do gamers ever do that with their PC's? Why wouldnt it be better to buy two cheap graphics cards instead of one higher end one? | Technology | explainlikeimfive | {
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"Sometimes yes, sometimes no. It depends on the problem if it can be solved in parallel or not. A task which depends on the output of a prior step cannot be worked on by another computer before the first is completed, so there are no benefits to having a bunch of computers linked together for that. However other kinds of problems can certainly benefit from clusters of computers. > do gamers ever do that with their PC's? Why wouldnt it be better to buy two cheap graphics cards instead of one higher end one? For Nvidia the technology for this is called \"SLI\" or Scalable Link Interface. For AMD it is called CrossFire. Usually it is employed with several relatively high end graphics cards rather than trying to do the cheap end because the cost to benefit doesn't really work out favorably.",
"Yes and no. There are several programs that utilize surplus computer cycles. Programs like folding@home use your computer during downtime to help compute incredibly complex functions like weather forecasting or amino acid growth. Here is a [list]( URL_0 ) of current and former projections that used distributed computing. The biggest hurdle with using this concept for gaming is speed of data transfer. Sure you could hook-up 2 machines, each with its own graphics card and write software to split the visual computations between the two machines, but it would be a lot faster to put the 2 graphics cards in the SAME machine and have them work together. This is how server blades work, dozens of slower chips working together on the same motherboard versus several machines cables together having to pass their shared information thru software that allows different machines to work together. ."
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hqshfx | Why do you still have to close files in order to move them to a different folder? | I've never understood why, even on Windows 10, that you have to close a file before moving it to a different folder. It seems like an archaic holdover from more primitive days. Why can't this issue be fixed? After all, you can now attach an open file to an email, something you couldn't do in Windows 95. It seems like it would be an easy enough thing for a computer to understand that you want to store something somewhere else now, even if it is open. | Technology | explainlikeimfive | {
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"This is intentional. The operating system knows which files still have running programs referencing them. Moving a file will invalidate the references. It isn’t enough to “notify” programs holding a reference to they file — a program might not be coded to handle such a notification. Therefore, Windows explicitly returns an error when trying to take an action that would interfere with a file reference. Linux handles it differently. Linux allows the file operation to go through, but doesn’t actually do anything until all references are dropped. Once they’re dropped, the file is then deleted. This, in my opinion, can be worse, because it can result in file leaks when a program is incorrectly coded to forget to close files. You can call delete on a file as many times as you want and it won’t actually free the space until nothing has it open anymore. I don’t have an answer why Microsoft decided to do it one way and Linux the other. It’s just what they decided. I consider both of these methods to be better than the third option, which is to just delete the file immediately and crash any other programs using it. It’s probably impossible to ever change Windows file handling without breaking backwards compatibility with... everything. Here is some more information about how Linux handles deletion URL_0"
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hqszf3 | How did early pioneers of the computer actually manage to turn ones and zeroes into something more meaningful than on and off? | Technology | explainlikeimfive | {
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"Humans have been using the concept of using one thing to represent another for thousands of years. [Drawings on a wall represent real animals and objects]( URL_21 ). [Symbols on a paper represent stories and ideas]( URL_15 ). Small bits of rock or [metal represent wealth]( URL_17 ). Numbers represent [letters of the alphabet]( URL_11 ). Different cultures in history have used [different number systems]( URL_12 ). Binary is just another number system, it was even [used before computers existed]( URL_4 ). So the process of using a binary number system, and using those numbers to represent other forms of data (letters, measurements, instructions) isn't all that novel or new. In terms of computers, it was obvious pretty early on that binary was the way to go. It's faster, cheaper and easier to develop electrical components to behave in certain ways in the presence or absence of electricity, rather than trying to get them to respond differently to varying levels of electricity. So using electrical components to work with binary numbers, and using that binary to represent all kinds of different data and instructions, was almost a natural fit conceptually. Not to discount the work put in by many smart people over many years ([Babbage]( URL_24 ), [Lovelace]( URL_25 ), [Turing]( URL_10 ), [Boole]( URL_22 ) to name a few), and the foundations that they build on from centuries of others ([Fleming]( URL_18 ), [Zuse]( URL_23 ), [Faraday]( URL_0 ), [Ampere]( URL_2 ), [Bardeen]( URL_3 ), [Edison]( URL_14 ), [Leibniz]( URL_20 ) for example). Of course once you have the foundations and the concepts that you can use to represent data using binary, you need to develop actual standards for everyone to follow, otherwise it's not much use. For this we have people like [von Neumann]( URL_16 ), [Wheeler]( URL_5 ), [Bemer]( URL_27 ) and [Ritchie]( URL_7 ) who pioneered modern computer architecture, programming and [ASCII]( URL_28 ); companies like [Intel]( URL_19 ) or [Arm]( URL_9 ) who developed modern instruction sets (mapping electrical signals to processor instructions); as well as groups comprising multiple people and companies, like [IEEE]( URL_8 ), [ANSI]( URL_6 ), [Unicode]( URL_1 ), [ISO]( URL_13 ), [IEC]( URL_30 ) or [MPEG]( URL_26 ) who develop standards for storing or transmitting different types of data using binary. Other than that, it's up to individual developers, organisations or industries, to standardise how they want to represent their specific data. As for the result being more than just \"ones and zeros\"; switches, LEDs, speakers, and eventually keyboards, mice and monitors were also developed by numerous people before and during the computer age, along with their associated standards. The earliest computers used electromechanical switches and lights, then later we used punch cards, printers, [teleprinters]( URL_29 ), keyboards and all the input and output devices we use today.",
"You can write any number in math as ones and zeroes. EG 0 = 0 1 = 1 10 = 2 11 = 3 100 = 4 101 = 5 And so on, with some different tricks for writing negative numbers and decimals. Basically you do the same thing in counting when you hit a 9. EG 7,8,9,10. Except instead of waiting for 9, you start doing it at 1. So they would turn the numbers they wanted to math at into ones and zeroes. The computer would feed that into logic circuits to do math, and spit out more ones and zeroes. And then that would cause lights to turn on or a printer to print out, then someone would turn it back into a human readable number.",
"They didn't do it all at once. Sound, touch, GUI came slowly over decades, and were preceded by early attempts at such. For example, [some of the earliest computers]( URL_0 ) already had sound and it was quite a novelty. As far as how they go from 0101001 to a GUI: layers and abstraction. Over the years, the programming languages as well as the operating system added layers on top of the gritty \"low level\" stuff, so the programmer only worries of the \"high level\" - not the 1s and 0s. In early computers, there was no choice, computers were slow and hand-tweaked. As computational power increased, the need for suck tweaking went away.",
"Somebody needs to play nandgame and get a look at how logic functions are built out of binary states - URL_0 I know that's not the *exact* question that was asked, but it's fucking cool.",
"Computers started off as tabulators and calculators. Instead of working in decimal, they worked in binary. Eventually they were hooked up to input and output devices that would translate between binary and some other format (decimal, octal, hexadecimal and ASCII letters for the most part). But the actual computer still speaks binary to this day.",
"1. First you realize you can turn on and off into a series of numbers using base 2 2. Then you realize you can do operations on those numbers. Add them. Subtract them. Divide with remainder. multiply. You can make a calculator for each! Then we can send that electricity to some lights to tell us what the answer is! We can even arrange the lights so they kind of look like the number we are trying to output! 3. Then you realize that if you assign each of those operations a number you can write a strip of numbers that do an arbitrary thing instead of just one thing. Now you can do entire equations at once! 4. Hear me out here, what if we had multiple strips of numbers? One of them has a complex set of operations on it, and another one has the input numbers you are interested in performing math on. Also you can add some operation numbers that don't do any math, but instead control what number to read next on the program tape, or what numbers to read or write onto the numbers tape? Now we can do some really complicated stuff. Tell it to calculate a number, write it down, jump back and run the same program again to build yet another number! Do that until we have a whole table of numbers! Send that electricity a printer at the end. 5. Ok so remember how we had two tapes? Scratch that! We only need one, and it can have both the program AND the input numbers, on the same tape! In fact, wan mix our program and our data together! Now we can write numbers, and then use those numbers as our program. The possibilities are endless! We are going to need a lot of inputs though! Something fast to read and reasonable for humans to write. Punch cards! And we can make little typewriter things to help you punch holes in them faster. Just don't drop your stack of them, or you will have to spend all day putting them back in order! 6. Remember how we can jump forward and back on the tape? Well we figured out how to do some really interesting stuff where we have come up with little mini programs that take a blank space on the tape, set up a little workspace for themselves, do their jobs, and then clean up their own workspace, leaving only a numeric result when they are done. Since they don't mess up anything else around them we can actually just have one of these mini-programs call other mini-programs and they just stack up their frames neatly and never interfere with each other. We can use these to model mathematical functions really well, so we will call them functions. 7. Functions are awesome. Instead of having to do everything myself I can just take the program someone else wrote and just plug it into my program. If someone came up with a bunch of ways to manipulate a oscilloscope I would be able to everything they figured out how to do without having to do it all myself! Now we get to think abstractly about problems instead of always worrying about what on and off means to what ever specific hardware all the time. 8. Ok, so punch cards are hard. What if we made input devices that make a single electoral contact into an entire number automatically? We could make a whole board of buttons that generate electricity instead of hole punches. Like a typewriter for electricity! Oh, and you know those oscilloscopes that draw a line on a screen? Turns out we can make those go real fast, and make programs to turn that laser on and off so fast we can make it look like letters. Sure, making the laser draw numbers is pretty hard, but someone already wrote a function so I can just use that. This is much easier to work with. 9. Remember how we had to memorize a bunch of numbers to tell the program when to add and subtract, or go forward and back on the tape? That is complicated, and there are some disagreements about which numbers should do what, so instead of writing all of our programs in numbers lets come up with really short names for all the things we can do, and then we can have a program who's only job is to take the letters and assemble them into code for us so we don't have to remember all the numbers anymore. 10. Now that we aren't having to throw around a bunch of punch cards we really need a program on the computer to start with enough smarts to let us tell the computer what we want to run today. Just enough so we can operate the system. Lets just leave that on the computer and come back to it when we need it. 11. So assembly is fine and all, but what if we got to talk to the computers like they were people. Like we would have verbs, and define terms, and all kinds of crazy stuff. We will make it so good at understanding people we won't need these programmer types anymore. we can use a program to turn human language into computer language. COBOL has arrived. 12. Ok COBOL didn't work out so great, but I still think the idea is good. Lets stop trying to put programmers out of a job and just make more convenient ways to write computer instructions. 13. So we can make the oscilloscopes draw pictures. I was thinking what if had some numbers that represented different things about a fictional world. We could make functions that change those numbers when you pressed buttons in a way that kind of made sense. Then based on those numbers about the fictional world we can draw different things onto the screen. Look! I made it look like I am shooting a demon with a shotgun! 14. This demon shooting thing is pretty cool, but it would be way cooler if I could do it way faster. What if we made a special computer that was really really good at doing the exact same operation over a lot of data? I know, I know. Usually want to do different things with the different numbers. But I bet we could draw way bigger pictures on the screen if we had hardware that was dedicated to this graphing kind of stuff. We could make huge fictional worlds with crazy illustrations and pretend we were going inside of books! 15. Turns out people like to do more than one thing with a computer at a time. The plan is our operating system run programs like they are little programs inside the computer! Turns out all the demon hunting paid off because now it seems pretty easy to just pretend all our programs are digital objects we can move around like windows on a little make believe desktop. Its like a game, but for boring people! 16. November 13, 2007 - Crysis is released for PC That should cover all the important steps.",
"what does a \"thumb up\" mean? how about \"two thumbs up\"? why does holding up your index and middle finger in a \"V\" shape mean \"peace\" today? we decided and agreed that those finger signs had meaning. when a group of people can agree that any symbol has meaning they can use that symbol to communicate ideas. as blorentz38 said - it's kind of like morse code - they created a symbolic lexicon from just dots and dashes. Computer pioneers just expanded on the idea with a larger \"vocabulary\" made of combinations of two simple things (1's and 0's instead of dots and dashes)."
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hqun3l | Why are physical passports necessary in 2020? Why isn't there an optional system in place which uses fingerprints? | Technology | explainlikeimfive | {
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"Every country in the world runs their own passport and custom systems differently butgenerally interchangeably. This means that countries like Germany that could afford to use fingerprints only have to have passport technology which is compatible with Somalia and technically even North Korea. Not every country has the resources or infrastructure to run fingerprints in a large international database. Countries also do not trust each other. Could you imagine countries like Iran handing over all of its passport fingerprint information over to Israel or vice versa? Some of this institutional mistrust over a central database is not misplaced, since it would be likely that someone in some country might sell the database off and comprise the whole thing. Passports also have a practical purpose once inside a country. If you are stopped by police it is unlikely that they will be able to use your local id card such as a drivers license to identify you. This is because they do not have access to the foreign database where you are from. A passport is sort of like a extended physical ID for international travel that can be verified just using eyes. Fingerprints can't be verified just using eyes. A fingerprint only system would require police officers to either take you back to the station or have a usable fingerprint reader on them. This assumes that they even use digital fingerprinting scanners. This is not limited to third world countries. Where i live in Canada, they still use ink fingerprinting at the police station. It also assumes that they have internet access and database access to use your fingerprints. The same thing also is true for booking hotels or verifying id for buying booze or cigarettes. People do not like your foreign id cards in other countries since they do not operate with their scanners and they frequently have never seen one before. This is also problematic when in foreign regions or remote areas such as when hiking or in small villages. Imagine trying to use a fingerprint reader in the middle of the Himalayas or the Amazon jungle. The officer reading the fingerprint would need to bring the reader to a remote location and either have database access or the whole database on the reader. This would cost a lot of money. Not being able to verify the passport on the spot creates issues for visas. Many countries, like Russia have visa requirements where you can only go to certain parts of the country or need special permission to be in some regions. Having a physical visa allows officials to casually check where you are supposed to be in the country easily without the need for high tech solutions. Ditto for expired or invalid visas.",
"Because there is no world database of fingerprints. Unless you are a criminal, or work for certain parts of the government, your own country probably doesn't even have your fingerprints.",
"“Something you have, something you are, something you know — pick two.” You need at least two factors for any decent security scheme. Fingerprints or facial recognition alone are not enough. And it needs to be something that works just as well at the Congolese border as it does at LAX.",
"Fingerprints are actually pretty terrible for identification. They're easily spoofed ( [ URL_0 ]( URL_0 ) ) and if someone does get a copy of your fingerprints, what do you do? You can't reset them, like you can a password. They are compromised forever. And do you really want China or Saudi Arabia to have a copy of your fingerprints?"
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hqw0j1 | Why do government broadcasts have sign interpreters instead of just subtitles? | Technology | explainlikeimfive | {
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"Because American Sign Language is it’s own language that has it’s own unique grammar and syntax. Also there is a large number of deaf people who don’t read english well because of educational barriers for deaf people (particularly deaf children born to hearing parents). So as far as accessibilitiy goes having an interpetor is more effective.",
"Broadcasts like those are usually live, and subtitles take time to put in. If they're available, they're autogenerated by a computer, and are handled by whoever is handling the broadcast. The government has no power to just make subtitles appear. Additionally, subtitles don't exist for people who are attending in person, although Google is working on that, probably. So yeah the government can't guarantee that subtitles will be available for whatever they put out. No reason not to have an interpreter."
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hqyjcn | How do lights in digital radios / alarm clocks / keyboards / etc, stay on for years and years without ever burning out? | Technology | explainlikeimfive | {
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"They use LEDs at relatively low power. There is nothing that really cause them to burn out like other light sources do. Most other light sources like incadecent bulbs or fluorecent lights have parts that require very high temperature to give off light. This can cause them to degrade over time and eventually fail. A lot of these are also engineered to fail after a few years requireing you to buy new ones. Even LED light bulbs have issues with heat as they are passing a lot of current to get the bright light to illuminate the room. Industrial LED lighting usually comes with big heat sinks to get rid of the heat.",
"They're normally not driven very hard. The LED in a modern flashlight, or indeed car headlamp will have quite a short life in the grand scheme of things. Longer than an incandescent bulb, but LEDs do dim over time, and wear out if they get hot a lot, which a powerful one will. The LED that tells you whether your Num Lock is switched on is relatively speaking, very dim, and low power, and will run for decades without a problem."
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hqyvqn | what does the memory mean in a Macbook? | so, i’m planning on getting the Macbook Air and i don’t know if i want 8 GB memory or 16 GB, basically what does memory mean? will the computer be stronger with 16 GB? | Technology | explainlikeimfive | {
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"Your RAM or memory is what allows you to multitask. If you have more RAM you can have more operations as well as more complex operations running at the same time. It depends on how you'll be using your Mac. If you need heavy video editing etc, you'll want more RAM. Of yoy only need browsing and creating documents etc, lesser RAM is enough but you can still go for higher RAM.",
"TLDR: is your desky messy and covered with the things you are working on? If no 8GB is fine. Memory, or RAM, is where software stores information it needs to access quickly. & #x200B; One dated metaphor might be to think of memory as the space on your desk, where you keep the papers you are currently working on, while a filing cabinet or bookshelf more like a hard drive and backpack would be more like portable drive. The filing cabinet can store a lot more but to do that has to organize them in a way that makes picking an individual item out take more time. More memory is like having a bigger desk, you can have more active projects and work on bigger projects. Like space on your desk you can free up memory by putting away things you are not currently working on, closing an application or browser window you don't need open right this moment. As a general student (meaning not one with a computer focused major like digital art, music or some engineering fields) the largest use of memory is probably going to be a web browser with multiple tabs open while doing research. As long as you are not like me and don't keep dozens upon dozens of tabs open you will likely never notice the difference between the 8 and 16. (i am currently using about 20GB or ram to run a web browser with dozens of tabs across 10 browser windows, also my physical desk has about enough free space on it to write a note on a post it without me having to move something, don't be like me)"
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hr3bar | How do you program the concept time into a software system? | Technology | explainlikeimfive | {
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"There are crystals that when electricity is shot into them, they slightly expand and contract at a regular rate. This size difference can be measured.",
"That depends on what you're doing with time. There are hardware devices that can keep time that keep accurate time in a way that can be read electronically, so if we know the electronic input/output then we can make seconds happen electronically, and have time happen that way. Most other things that deal with time either are derived from that, or from some other thing that should be happening at a steady rate in the software. For instance, in games, if there is some time element that might be tied to the processor speed (often in consoles where the processor speed is constant across consoles; some early/bad console ports have speed issues because of this), or they might use the computer's internal clock to coordinate things. Finally as for computers telling time, there's a whole protocol and network system to keep computers in sync with each other that you can use to keep all your computers agreeing on what time it is. Basically by default, you will use a local server as the \"master\" clock, but that local server will use a higher-level server, and so-on until the chain ends at one of the several nuclear clocks that we have that are used as the standard of what time it is officially.",
"So there are a couple clock mechanisms in your computer. One is a sandwich of two quartz crystals. When you electrify one, it changes shape, when you change the shape of the other, it produces a current. So these two crystals are locked in a loop where they jostle and electrocute each other. Based on their geometry and temperature, you can get a very reliable, regular, pulsing mechanism. Count the pulses, you have a clock. This is how quartz wrist watches work, and they take very tiny electrical currents to operate, which is why those old watches could operate on a battery for months. When your computer is shut off, there is actually a battery onboard that keeps the clock going, to keep the machine's clock up to date. Your processor doesn't use this clock function directly. It has a pair of transistor gates, what's called an a-stable flip-flop. This is a circuit with a feedback loop that flips the gate open when it's closed, and closed when it's open. This is how the processor keeps track of time at extremely high speeds, and it's where the processor's frequency comes from. The frequency is controlled by voltage, and has some sort of mechanism to hold *relatively* correct to the reference frequency. I'm not exactly sure how this is done - I forget, but I think the processor compares it's internal time with the system clock and adjusts voltage accordingly. All clocks are affected by heat. The hotter these clocks get, the faster they run, so they need to be constantly regulated. Your system further keeps time relative to some standard reference. In the US, that would be the NIST, which maintains an official atomic clock that is our nation's standard. It is the definition of what time it is. There is a mechanism to align your system time to this reference within some reasonable accuracy. Atomic clocks are cooled to the point where basically heat is no longer a factor in how the mechanism works. They operate at super high frequencies so they can track smaller units of time. When you get down to those scales, relativity becomes significant. As the sun warms the surface of the Earth, the crust expands and changes the distance of the clock from the axis of rotation of the planet, skewing the time. The material of the crust, the kind of rock, its thickness, changes how it expands, and so two atomic clocks really any arbitrary distance away from each other will measure different times because of this rise. In the 90s, there was a company using atomic clocks to prospect for oil using this technique. I don't know how successful they were, but the concept is sound enough that they tried.",
"With a clock. Computers have electronic clocks in them, in fact it's a fundamental part of how they operate as the electronics within a CPU have to operate in a synchronised way. The clock is a crystal that oscillates a predictable number of times each second when electricity is passed through it. Counting these oscillations allows the computer to measure the passing of time.",
"There's tiny crystals that vibrate very regularly when excites with electricity. There's hardware that excites the crystals and then keeps track of the pulses . The computer reads this hardware to keep track of time."
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hr5y04 | How can significant changes be made to video games from beta to final product in a month before release? | Currently playing a beta of an upcoming game and have no idea if/how much the developers can change things when there’s a month before release. When there is already so much work and detail put into creating a video game over years, how much can really be changed in a month or even a few and how? | Technology | explainlikeimfive | {
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"The biggest changes are sweeping changes, like the algorithms used by non-player entities. The texture on that chest is just one of a zillion textures. It's not like changing all the textures is feasible, so changing that one needs to be for a very good reason.",
"There's some differences in the types of changes that can be made. There's fundamental changes to something like the game engine or entire game mechanics in the game. Taking an FPS and adding in a brand new vehicle and driving system is probably hard and couldn't be done easily, it's a fundamental shift in the game play and the objects and interface and physics etc... But sometimes you could make a big change to the game play, balance or feel and look of the game that doesn't actually require a huge change to the underlying mechanics of the game. You could take the same fully developed team based FPS mode and add in a Battle Royale mode and its probably not that hard. You haven't changed the characters, the guns, the physics, the damage, the movement or anything, you've just created a bigger map with more players and added some shrinking zone mechanic. A good example is Fortnite, originally a co-op building game turned into a Battle Royale and done pretty quickly in a Strategy game like StarCraft 2, the unit statistics in the Beta were very different from the actual launch for both the original game and both expansions, in many cases a complete redesign, deletion and addition of units. This vastly affects how the game plays, but it doesn't change how the game 'works' In fact in many games like Warcraft 3, StarCraft and StarCraft 2, because of map design features in the game, you can see how its actually quite possible to take the base design of an RTS and within a few weeks of work of a single coder, turn that game into a Tower Defense, a Version of Mario Party, into DotA, into an RPG, into a Diablo-clone etc..."
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hr89bd | How are sound and video perfectly synchronised in film? | I know that sound and video for films or other video productions in general are recorded on separate channels and then combined together during the editing stage so my question is how that process works and how do they achieve perfect synchronisation so one of them isn't delayed. | Technology | explainlikeimfive | {
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"Have you ever seen those big clapper boards? Someone holding a board in front of the camera goes \"scene 1 take 1\" and the board makes a loud-ish and sudden sound? That sound is sudden, loud, and distinctive. And because someone held the board in front of the camera they they can see where in the video recording it happened. So they look at the sound file and see when the big load snap happened. And line that up with when on the film that sound happened. Now its all just computers with time codes you can see. Also, this is mostly pedantic, sound can actual lag behind the visuals by a small fraction of a second (sometimes up to 250 ms I think) and you won't notice it. This is because light travels faster than sound. Back in the 50s i think sound engineers for TV were super worried about keeping sound synced perfectly until they discovered this.",
"On celluloid film, the sound is provided on a \"strip\" on one side of the film. It's virtually impossible to get out of synch once it is correct, since they are both running through the projector together. On digital movies, there are time stamps embedded within both the video and audio streams. This enables the playing device to make sure that they are both in synch. When a movie is compressed and decompressed for transmission, it is possible for the audio and video to get out of synch due to issues at either end.",
"It depends on the type of video production, but generally they use some sound that is directly connected to an on-video visual cue. In film, this is achieved with a [clapperboard.]( URL_1 ) The top bit falling down onto the bottom bit makes a loud, distinct \"CLACK\" sound that is picked up on the microphones and generally produces a large distinct spike in the audio level visualization, so the editor finds the instant where the clapperboard connects, marks that frame of video, and then puts the audio such that the loud clap is at (or at worst slightly after) that frame. In things like Let's Plays (for those playing the home game: online shows where people talk over footage of themselves playing a video game), they will usually go to a menu screen or something similar where there's an obvious visual indicator of what their control is doing, and then they will announce what they're doing as they do it, generally in a cadence that has some tempo variance so that they can know they're getting the start and end right. [This video]( URL_0 ) shows this starting at about minute 8 and explains how that works a bit more in depth. It's a much more iffy process since there's no way to make something physical appear in that footage and make a sound that gets picked up in the audio capture, since generally you try to not get the game audio in your spoken capture (because if you're even slightly off with audio, it will be obvious, and even if you aren't the capture audio is going to have different audio characteristics than what the mic picks up), and it's a relatively new form that's still developing best practices, but I digress. In both instances, the points used to synch up audio/video gets cut out of the final product."
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hr8z8n | Why the ‘Bullet Time’ effects from the Matrix were created using hundreds of cameras all situated in a circle around the objects/people being filmed instead of one or two cameras that were setup to quickly move around the objects/people being filmed. | Technology | explainlikeimfive | {
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"Uncertain, but I think it's to do with motion blur. A camera works by opening the \"shutter\", a physical cover that stops light getting onto the sensor (the bit that records the colour information), for a small amount of time. If you open it for a very short time, you get a dark image (because the sensor only sees a little bit of light), and or you keep the sensor open for a long time and get a much brighter image. The problem with keeping it open for longer is blur. If things move whilst the shutter is open, then the final image is blurred. So, to achieve bullet time, you could move one camera very fast - but then the camera would move whilst the shutter is open, and the image would blur. Or, you take lots of still images, and because the camera doesn't move, you get a less blurry image (there's still a little bit of blur because of the person moving, but the background isn't blurry at all and the person moves much slower than the camera would have to).",
"I got curious as to the actual math behind how fast the camera would have to be moving in order to use only one camera moving in a circle. I don't know the actual numbers, so I'll have to make a few assumptions: Let's assume the camera is 10 feet from Neo. That's pretty close, and in reality it could easily have been further. Let's also assume they need the camera to make the full circuit in a quarter of a second. The illusion we want is that we've captured a single instant in time, therefore the duration needs to be pretty short so that we capture as little of Neo's falling motion as possible. A quarter of a second is pretty noticeable as Neo's falling motion goes, so the actual maximum duration was probably less than this. 314 feet traversed over a duration of 1/4 of a second is 1256 feet per second. That's 856 miles per hour. I'm not an expert on cinematography, but my guess is that you'd *probably* get noticeable motion blur from this. Even if we halve the camera distance to just 5 feet, which is *really really close* to Neo, the camera would still have to be moving at over 200 mph. A 20kg camera moving that quickly might be *slightly* dangerous to be within 5 feet of.",
"Another thing to consider is that one of the bullet time effects was not merely slow motion, but to have the action pause completely, swing the camera around the frozen actors, and then resume. To do this you need all those cameras capturing the moment simultaneously.",
"Motion blur is part of it, but also remember at the time the Matrix was filmed, they were still shooting on film. Film adds a lot of weight to an already heavy camera, making quick, precise movements very difficult. Now with digital cameras, we can lighten the load and attach cameras to robotic arms that can travel extremely fast and execute exact moves over and over. Here's an example: URL_0"
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hr9w9z | How does my computer prevent feedback when on a video call and my mic isn’t muted? | I don’t understand why, when video conferencing with two computers in the same room, one will pick up the other’s audio as feedback yet my computer doesn’t pick up its own feedback when I’m by myself in a room on a video call and the mic isn’t muted. | Technology | explainlikeimfive | {
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"Because your computer _knows_ what its sending out of _its_ speakers/headphones/audio out and will actually _cancel_ that signal out of anything coming in from your microphone. Same reason why a conference call phone or a phone on speakerphone doesn't have the problem yet when you bring another phone nearby you get feedback. Since the dawn of conference call phones self-noise cancellation has been a thing. To a point, and it depends on which apps are in play. If you use VSee or Discord for gaming with friends, but have the in-game audio chat coming through as well, you might get your voice comms bleeding through the game output at the same time - the game can't know what you're talking into Discord unless Discord is integrated into the game / platform (like Steam). If you mix Discord or Skype with ingame Steam chat for example you get weird results and echos and bad news."
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hrarwj | Why are computer CPUs the size they are? Wouldn't making them bigger give way to more processing power without needing better technology? | Technology | explainlikeimfive | {
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"Couple of reasons: - You lose efficiency, which ultimately slows processors down - You increase signal noise, which means that more resources have to be used to error check - You generate _a lot_ more heat, and heat is already a big problem with processors. And finally: - Cost. The wafer in the chip is the main expense, so increasing the size of the wafer directly increases the cost of the chip.",
"There isn't a set size for CPUs (and GPUs and other processors) and some are physically larger than others. Sometimes they do make them larger for more processing power, but there are some practical limits. One is that there will always be a chance of a defect in the silicon. The larger the CPU, the more likely that it will have a defect. Although there are ways to mitigate this somewhat, it means that a larger chip will cost more because more of them will have to be thrown away due to manufacturing defects. Another issue is that the silicon wafers that CPUs are made on are round because of the process used to make them, but the CPUs themselves are rectangular because the wafers then have to be cut apart into the individual CPUs. Take a circle and try to fit as many small squares on it as possible. Now, make the square much bigger and see how many squares you can fit in the same circle. There's a lot more wasted space near the edges, which also makes larger chips cost more. Power is another issue. A lot of devices (laptops, smartphones, tablets) have limited battery capacity because they have to be portable. Making a processor bigger without improving the technology will increase power consumption and battery life is important for mobile devices. And for devices where battery life isn't an issue, heat is. CPUs produce a lot of heat for how small they are. Keeping them cool enough that they don't damage themselves is important. A datacenter consumes as much electricity as a small city, and on average 30-40% of that is used for cooling. The bigger the processor, the harder it is to keep cool.",
"Two main reasons they don't do this: 1. Electricity is fast but it's not infinitely fast; if you make the chip bigger you're bouncing signals further which takes longer and that adds up over time. 2. The silicon they make these chips out of is a type of crystal, and the bigger you make a crystal the more you risk it having a flaw somewhere. By making smaller crystals they can better control the process and have fewer failed chips.",
"One thing I didn't see yet: *the literal speed of light*. At 5 GHz (a high-clocked CPU of today), light just travels 6 cm in one clock cycle, which means an electrical impulse cannot get further as well. Clock signal propagation is already a huge deal in CPUs, since the timing of a signal is often vital. The bigger you make the chip, the harder this clock problem becomes.",
"Signals travel at finite speed, so the further apart bits of the CPU are the slower it must run.",
"Heat/power. Processors already use a huge amount of power, and their cooling systems hence have to remove a lot of heat. This would be somewhat manageable by using many cores in your larger microprocessor and shutting down the ones in use. But it still would be expensive and difficult to supply the peak power and remove the peak heat. Not impossible, though. And your software would need to be able to take advantage of having many cores available or it would be pointless. Cost. Large die are more expensive than small die, and the larger the die is the greater the chances of having a critical defect. This can also be somewhat managed with redundant memory and fusing out defective portions of the chip. Of course, excessive cost isn't something that would make it impossible to make larger chips, it's just bad business. There's a practical limit to how large you can reasonably make a single die with existing technology. The photolithography process must be able to focus an image across the whole thing. This is perhaps the biggest impediment, as some chips are already as large as can practically be made with today's equipment. (Not mass market microprocessors and GPUs, though. Mostly things like network processors.) You can make larger chips by \"stitching\" multiple die across the normal boundaries, but that does impact performance. Some people have mentioned the signal transit time (\"speed of light\") as an issue, but that's not really a major obstacle. There are lots of ways to mitigate that with little or no performance hits. It does make the design a bit more difficult, but not impossible. *Source: I worked on various types of processors for most of my career.*"
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hrcn4z | How do weather instruments calculate where lightning strikes? | Technology | explainlikeimfive | {
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"There are lightning detectors all over the world. The radio transmissions from lightning are very strong and can actually go around the earth several times. Next time there is a storm nearby sit in your car and turn on the radio, switch it to AM and tune to a frequency that is quiet, no music or anything. You will hear static bursts, that is lightning. DO NOT do this in the middle of a storm, stay inside. There is no danger from listening to the radio, just don't go out to your car in the middle of a storm."
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hrfdrr | How is volume typically calculated on devices like iPhones, laptops, TVs, etc...? | If the volume on your tv goes up to 100, is volume level 1, 1/100th of 100 and volume level 65, 65/100th of 100? Or is volume scaling at a different rate? If so, does this vary across devices? It seems with TVs especially, that there is often a point where the increase in volume from one number to the next is too drastic to be one equal “amount of sound” as the last, if that makes sense. I’m sure there is a better way to phrase my question, but I hope this communicates what I’m asking well enough to get an informed response! | Technology | explainlikeimfive | {
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"Usually it's because of how we percieve sound, and limits on the speaker hardware. For one audio amplification doesn't directly correlate linearly to loudness. It's logarithmic, ish and if you try and use a linear scale for volume it's bad. It's a pretty big mistake so that shouldn't be the reason -too- often. Though there isn't much engineering put into cheap TVs. What should generally be causing the problem is that lower frequency bass sounds are both percieved as louder, and harder to generate with small speakers. So at a point the low frequency sounds stop getting louder while the high frequency ones have a lot more room to increase because it's easier to make louder high frequency sounds with small speakers, and less electrical power. End result is a sudden drop off in how loud everything seems in total. In principle of you hooked up a nice audio system to your TVs audio ouput the scale would seem more accurate.Or if the TV programmer had enough time to actually adjust the scale based on real hardware rather than using whatever default settings were in whatever software/hardware library they were using."
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hrfgzg | Why do you need to press so many buttons to start a plane? Can’t there be just one button to start everything in sequence automatically? | Technology | explainlikeimfive | {
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"You don't \"start a plane\" You start individual components that all are a part of a plane. These all are separate for redundancy and to give the crew the most options in isolating a problem should it arise. Let me summarize a Boeing 737 startup procedure here (every operator is different, so this is a very loose walk-through). 1. Parking Brake Set, verify Brake Pressure. 2. Battery On, Standby Power On 3. Fuel Pumps Set as required 4. APU Start (Auxiliary Power Unit, provides electric, hydraulic, and pneumatic power for extended ground operations and for engine start. 5. Aircraft lighting set as required. (About a half dozen switches here alone) 6. Passenger Signs as required (Seat Belt/Electronics/No Smoking/etc.) 7 Packs to AUTO/High (This is the Air Conditioning System) 8. IRS OFF- > NAV (Inertial Reference System, consists of gyros, computers, and GPS system) 9. FMS SET (Flight Management System or \"the Box\". The computer heart and soul of the avionics system) 10. Transponder SET (Transponder or XPDR is the box that communicates with Air Traffic Control to relay aircraft information) 11. IAS/MACH Speed SET, Altitude SET, Heading SET (Set the autopilot) 12. Yaw Damper ON (Yaw Damper helps fight a phenomenon known as Dutch Roll caused on fast moving aircraft, basically tail slides opposite of roll and oscillates back and forth. Can cause motion sickness pretty quick) 13. Window Heat ON 14. Set Pressurization system as required. 15. Flight Directors On (visual cueing system tied into the autopilot) 16. NAV systems set 17. Minimum approach altitudes SET 18. Altimeter SET 19. Autobrake RTO (Automatic Braking System to engage in event of Rejected Take Off) 20. COMM Radios SET 21. Doors Closed/Armed (Doors are closed and armed so as to automatically deploy slides of door is opened.) READY TO START (Thats right, engines aren't on yet) 22. Auto Throttle ARM (Autopilot control of throttles) 23. Left, Right, and Center Pumps ON as Required. 24. Electric Hydraulic Pumps ON 25. ANTI COLLISION Light ON 26. SEC MFD to Enginr Display (Center Panel Multi Function Display switched to show engine parameters) 27. PACKS OFF (AC turned off temporarily so the pneumatic air can be redirected to the engines for start. This is why the AC over your seat stops when they start the engines) 28. ENG 1 START to GND (Ground Start, spinning the engine up) 29. At minimum RPM ENG 1 Fuel Control Lever ON 30 and 31. Repeat 28 and 29 steps for second engine. 32. PACKS ON 33. VERIFY ELECTRIC VOLTAGE and AMP, systems to engine driven generators 34. APU OFF All of that is just to get the plane ready to taxi. There are many, many more things to be done before takeoff, en route, and landing. A Cessna 172 is much simpler, but I assumed from the OP question we were talking airliners as that is what most people have experience with. EDIT: Reddit formatting is a PITA on mobile. I give up. Hopefully the meaning comes through.",
"Because so many aspects of a plane need to have manual control for safety reasons. A pilot would maybe like to turn off the fuel pump to specific engines in case of an emergency instead of turning the entire plane off midflight. If a pilot can turn on a plane in steps he/she can detect problems before they engage the main engines, which prevents damage and potential death.",
"It's mostly because lots of things in a plane can be controlled and setup individually. The number of things you -need- to press to start is rather small, however the entire startup sequence is designed so that each individual system can be verified to be working properly, and and in addition that all the switches are in the right positions, in case some Yahoo flipped a switch and didn't put it back. Could things be computer controlled the whole way, sure. But programmers are notoriously imperfect and pilots generally don't feel comfortable without the ability to override things (even though most of what a pilot should be doing is going through a pre-planned checklist anyway.) Programming safety is fine for simple systems, but for really complex stuff there's so many things that might happen that the programming might not have accounted for.",
"The same reason why you need to turn the keys, press the brakes, and shifting your gear to drive before you can actually drive the car. Making these 3 actions into 1 button is just too dangerous. & #x200B; Edit: Although Tesla, it minimizes the actions to 2."
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hrgnp5 | why is camera zoom measured in millimeters? | Technology | explainlikeimfive | {
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"Focal distance of the lens. Of course, the x factor of \"magnification\" is related to sensor size too. It's focal distance and sensor size. That gives the true zoom value. But to answer your question, millimeters is because it's the distance from the lens at which parallel lines if light converge in one spot."
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hrjfme | Why is it that watching movies at 24 fps feels completely normal and smooth but playing games at anything below 50fps feels rough, laggy and like it's having constant micro stutters? | Technology | explainlikeimfive | {
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"text": [
"Motion blur. A videogame generates a sequence of static images. Meanwhile, a movie captures real life images which naturally makes movements a little blurry, which appear smoother when played back.",
"When you’re gaming you’re interacting and the tv is responding by showing you the results of your action so any delay becomes quite noticeable because we’re so used to everything being instant in day to day life. I assume films don’t suffer the same fate because they aren’t interactive.",
"You could generate the same low FPS effect in film if you wildly swung a camera around, but film makers intentionally don't do that. In film, shots are specially chosen and framed by the director, and the viewer's gaze is intentionally directed at a specific focal point in any given frame. And in film, camera movements are generally slow and steady, even if there are rapid cuts for high action sequences. Even with \"shaky cam\" effects sequences, the camera does not wildly and rapidly pan and spin around as it constantly does in a modern action game. In a modern action game, there is no director choosing the viewer's focus, or significantly restricting the camera movement. A rapidly panned environment basically turns to eye-bleeding mush. Note that a game can operate at lower frame rates and look much more steady, if the camera is locked, or moves very gently, like in a side-scroller fighting game, and this is closer to how a film camera might operate from a fixed perspective that makes slow deliberate moves."
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hrjnze | How was trance music and the likes made in the 90s, before the release of "user-friendly" software? | Technology | explainlikeimfive | {
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"Others have roughly given the answer. But.... Most of us had minimal gear. A lot of things like the \"acid\" synthesiser (the TB303) were cheap by 1988. They were failed products. The tb303 has an onboard sequencer, meaning a baseline could be programmed and played back. If that sequencer was synchronised to a drum machine then that was a start. Bass and drums in sync. The drum machine has its own sequence patterns stored on it. We could flip between our patterns, and twiddle the dials on both to vary the sounds, create fills and builds, etc. Playing some chords on the top (on a polysynth) we had the basis. The signals were mixed together in a mixer. Effects were added, for distortion perhaps just a guitar pedal. For echo and reverb the first cost effective digital rack mounted units were available. A step up was the first affordable samplers. In the late 80s AKAI released rack samplers (such as the s900) which were just about affordable. With just a few seconds of sample time it was enough for an \"aw yeah\" or a stab sound. Many people used an AtariST for sequencing. Rock solid timing and a built in midi port to trigger synths. But many older drum machines and synths lacked that connection, so getting everything in time was very tricky. Source: Am dance music producer from the 90s",
"People used hardware back then and analog sound signal, pushing actual switches, turning knobs and occasionally messing with the wiring to put the sound through different preset filters.",
"The Roland TR-909 was an important instrument in trance music. Check out the Wikipedia page here: [ URL_0 ] ( URL_0 )",
"Electronic music generation in the 80's and 90's wasn't as user unfriendly as one may assume, just fiddly to plug a bunch of stuff in. And the process of composing in modern multitrack software isn't that far removed. The difficult part was acquiring a bunch of expensive instruments in the first place, where now the computing power exists to build entire arrangements including virtual synthesis on a single relatively cheap computer. It was common to use a computer as a sequencer, even old 8-bit computers. But instead of those generating sounds internally, the various tracks were played back on devices, keyboards, drum machines, sampling units and other modules, chained together by MIDI cables. Also by mid 90's digital multitracking became relatively affordable outside of high end studios, at first exclusively on Macs when they were the computer for media, but later on even cheap PC hardware as well. Electronic recordings began to be more commonly assembled via digital multitracking inside of a computer, instead of purely generated by instruments in real-time. And by the end of the 90's it was becoming practical to generate an entire arrangement with software like Fruityloops, on a laptop even. And the ability to simulate an entire studio's worth of processing and mastering-style effects."
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hrlie0 | Why do newer apps take more resources even when doing more or less the same thing as before? | Technology | explainlikeimfive | {
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"To cut down time in developing apps, a developer rarely makes anything completely from scratch. Instead they use a pre-existing library of tools that's readily available, and makes developing a lot faster, and a lot less complex. As systems evolve, more and more tools become available, and these tools might take up more space, or use more system resources to do certain tasks because the task itself now requires more steps to complete. Some of these steps might be related to security, some might be to circumvent a design choice in how the system handles one resource that might be ineffective. Ultimately, you probably still could make apps that uses way less resources, but if they don't adhere to new requirements for apps (security, compliance, compatability) they're unlikely to be accepted and released on the various app-stores."
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hrs5pd | How are aliens expected to decode the golden record on Voyager 1 and 2? | I understand that an advanced civilization would have to use science to decode them, but how would they be expected to decode something that is based on human-constructed measurements, such as the use of cm, AU, time in seconds, etc. | Technology | explainlikeimfive | {
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"The golden record tries to take that into account. It has a number of aspects of math that are assumed to be universal along side how we notate that in our language. It then tries to define our units of measure using things we assume to be constant across the universe - eg. the gram is defined based on the atomic weight of hydrogen. The hope is that an intelligent species would realize the record is from another intelligent species and would be able to decode it; it is accepted that this process will take some effort, but assuming that their laws of physics and chemistry are the same as ours, it would be possible.",
"They didn’t use cm, seconds and such. They used a unit based on atoms (so basic physics) which should be readable by everyone if interpreted correctly. So the theory. VSauce has a great video on it. One controvers thing on the plate that might be too “human” is an arrow. Edit: [the VSauce video I mentioned ]( URL_0 )",
"The diagrams that show how to play the record does not use human constructed measurements. Instead it use fundamental constants like the time period associated with the fundamental transition of the hydrogen atom, and a diagram describing this as well. It use binary numbers and also a diagram showing how binary numbers work. The location of our solar system is described using pulsars. We have put a lot of effort into making these records playable even without any human cultural knowledge. We even included a stylus and a diagram of the record player.",
"We think we'd be smart enough to work it out. Think about just how much we've learned about the galaxy from extremely limited information. You put a few thousand of the smartest people on the planet onto a task and you'd be amazed what they can work out, and presumably an alien civilisation could do something similar.",
"u/ChipWhitley98 is an alien way out past Pluto, scratching his head while looking puzzled at the Voyager probe."
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hrtiba | Why do some software require a restart to work? | Technology | explainlikeimfive | {
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"text": [
"It resets the software to a known starting position. Its a little like your kitchen as you make dinner. If you just finished making dinner and I ask you to make _another_ dinner, you'd say Uh huh. The vegetable peels need to be taken out, there's flour all over the counter, there's no room for anything else what with the mixmaster and the bowls on the counter, the sink is full of dirty pots and pans, you have to wash your knives and the stove is dirty. You have to pick dough out of the blender etc. You could make another meal if you had to, but it wouldn't be as perfect and you'd have to work around the mess of the previous one. Same way for a piece of software or an operating system. As it works, it tries to clean up after itself, but bugs and defects mean over time it starts to leave a mess. Restarting the OS or the app sweeps all the mess away, cleans the whole kitchen and everything is ready to go again."
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hrw8i0 | How are bank balances stored? | Are bank balances stored as integers, a hash only the end user can decrypt, or a completly diffrent way? Could an admin in principle change his own balance to $1B? | Technology | explainlikeimfive | {
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"text": [
"Generally bank and other financial systems don't actually store a balance. Not entirely anyway. Usually they will save all of the transactions that the account has had, and add them all up to calculate the balance. Sometimes they will cache the number, and usually it will be only the transactions after a certain date. I.e. store the balance you had at the end of last month (so you don't have to calculate back to the beginning of time) and add up all transactions from that date until now. Source: I used to develop backend software at a fintech company."
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hrxg9f | Why does European 50hz electricity translate to 50hz refresh rate on displays? Does this apply to 120hz displays too? | Technology | explainlikeimfive | {
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"text": [
"Early televisions were synced to the AC frequency of power to avoid interference that would be caused by having them run on different timings. Even though we can design electronics better and make better parts than we could in the 30's, it's still easier to make displays work at a multiple of the AC frequency, and many European sets will operate at 100/200 Hz instead of 120/240 Hz. There's actually a second reason, which is that the lighting used on stages where they made the show were also flickering at the same frequency as the power coming out of the mains, and so you'd be able to see the difference if they'd recorded or broadcast out of sync with that."
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hrzw21 | How do we save an image in our computer? | How is it that we just right click an image and it’s saved? How does the computer know what to copy and how does it do it so perfectly? | Technology | explainlikeimfive | {
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"It might help to think of a simple image file as a little map and a set of instructions for reading the map! In the map part, the file gives the computer a grid and tells it, \"Okay, in this location on our grid, you'll have a red pixel. Right next to that one, another red pixel, and then two blues.\" So you end up with a grid of pixels. In the instructions for reading the map, the file might include rules like how many pixels fit in each row, the preferred resolution, info about whether the image is compressed, all that stuff."
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hrzxxj | How do jet engines work? | how do jet engines make a plane fly. and how do they spin so fast and loud? | Technology | explainlikeimfive | {
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"text": [
"Jet engines are basically two fans. One sucks air in and compresses it, while the other gets spun by the burned fuel/air escaping out the back. The back fan powers the front fan. Meanwhile, all of that hot air escaping out the back pushes the engine forward on their way out. These engines can spin very fast because, unlike car engines, they have no pistons or anything going from side to side. Rather, they are just spinning, and they are balanced very precisely. They're very noisy because the air leaves the back of the engine moving super fast and there is a lot of it, as well as the spinning blades (much like a fan) induce a lot of turbulence and whooshing noise in the air."
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hs1li0 | why are counterfeit items never perfectly copied ? | Technology | explainlikeimfive | {
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"text": [
"As with most things, economics. The original manufacturer has an incentive to hold a high quality bar:. It affects their reputation and their product reputation. Investments in quality can pay off. With counterfeit goods, the manufacturer has little incentive for such investment. Any reputation gain/loss would be on the original manufacturer, as well as people trying to get refunds. Counterfeits have little incentive beyond a good enough copy to fool buyers at purchase time. Further, counterfeiters are agile, moving from hot trend to hot trend, or away from where anti-counterfitting efforts might be active. This means less incentive to make a perfect copy if you are going to move on soon. Alternatively: If a counterfeit goes through the effort to have equal or better quality and keeps their sales to a small enough sector of the market that it goes unnoticed by the manufacturer, how would you know it ever happened?",
"It's also worth considering that it's only the nonidentical counterfeits that are discovered. Perfect or near perfect imitations may exist but people won't notice them. Who knows how much counterfeit money is out there."
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hs36lo | How does a dashcam work? Won't recording for a long time use up a lot of disk space? | Technology | explainlikeimfive | {
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"text": [
"It typically overwrites the oldest files when the storage gets full. Therefore its \"infinite loop\"",
"Different cameras have different settings. some have park mode that starts recording when there is activity on the screen. Others have a button that saves a set amount before you press the button, i.e. you press it if you want to record an incident And most will just record and save footage then delete it after say 24 hrs of recording"
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hs6oo0 | Why is it than we were able to put men on the moon with a 5kb RAM but my game keeps lagging and heating up my phone with a 4gb RAM? | Technology | explainlikeimfive | {
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"Because your game is immensely more complex than the lander's program. The math needed to land is easy. The hard part is engineering the rocket. Also, graphics are huge.",
"A host of different factors which I'll try to list here: 1) A computer (such as the one you're using), unlike the Apollo computer, is **NOT** specialized hardware. It is a general purpose machine. It is designed to do general computation. It was not **specifically** designed to render 3D images at a high framerate, even though that is one of the use cases (that's why we even have a GPU, which is a dedicated graphics processor, to begin with). Specialized hardware for that deal with very specific tasks will almost always win against other types of hardware. 2) The amount of calculations needed to maneuver a spacecraft in flight is **risible** compared to the vast amount of data processing required to calculate, tesselate, shade, raster, light and render a 4K frame of a game running at 60 FPS. 3) NASA has spent the better part of a decade devising very special, very clever ways of making computers and algorithms that can perform such tasks on an exceptionally low amount of memory. All of the code was painstakingly handwritten and verified by humans. It piled up to the height of a human when printed on paper. In contrast, 90%+ of the code used in running your game was generated by a machine. It's only as optimized as it needs to be for it to run decently. 4) With more memory/processing power comes more complexity with handling various tasks in parallel. It's why computers from the 80s don't \"lag\" the way modern hardware does. They either run or crash.",
"5kb of RAM didn't put man on the moon. 6.5 million pound rockets put them on the moon. The math required to guide those rockets can be done with a graphing calculator.",
"The computers on board the Apollo didn't try to create and display high resolution images at 30 FPS. They were just used to control the ship and calculate trajectories and such.",
"As explained to me a long time ago - maths is easy, 'making it pretty' takes a lot of space, power and effort! (i.e. graphics are the real consumer of device resource).",
"Economics. The purpose of the moon hardware *was the Moon*. But your game is (almost certainly) not the main objective of the game-maker - it's to use your playing of the game to convince someone else of a totally different business proposition, even if you paid for it. The rest records and processes for those other interests. So only a tiny fraction of the performance is about you or the game. If it were all about you, people could have been playing that game since 1995."
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hsc7jf | Why can't you install a program as it downloads from the internet? | Technology | explainlikeimfive | {
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"text": [
"Think of it like a car.... You can't drive it if you only have the wheels. A program is made of multiple files all packaged together inside the installer. When you install the application, the files are extracted and put into the correct places. If you don't have all the pieces the application will not work."
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hsgjhe | what exactly a factory unlocked iPhone is, and what you can do with it | Technology | explainlikeimfive | {
"a_id": [
"fya99b8"
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"text": [
"It means you can use it with any wireless carrier you want just by changing the SIM card. Usually phones are \"locked\" to the phone carrier in question - wireless carriers give the phones away in exchange for multi-year service plan lockin. If you could buy an iPhone from T-Mobile for $100 and then switch to Comcast they'd lose money."
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hshlcw | How do 1's and 0's and electricity tell chemical elements to move? | For example, a car or any other device with wheels moves. What I never fully understood is how the heck are they moving giant masses of sorts by that electrical and chemical process, and how rubber withstands that much metal on top of it. How exactly does data tell wheels to move giant pieces of metal? Is it the combustion process or the data doing the job first? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"\"Data\" doesn't move cars. Explosions in an engine causes a rod on the underside of the car to rotate, which rotates the wheels. I would recommend [this]( URL_0 ) video on how an engine works, and then [this]( URL_1 ) video on how a crankshaft works.",
"1s and 0s in a computer really just mean on or off. Is current flowing or is it not. 1 means current is flowing somewhere and 0 means it is not. A transistor makes it so that a small current flowing through one way (representing a 1) can turn a switch that lets a big current also flow. So that big current can do work. This is how a computer can control big machines. The small current turns on a big current that can drive a big electric motor. Or the big current can open a valve that lets fuel into a big engine.",
"If powered by an internal combustion engine, the movement comes from the power of thousands of tiny explosions happening every second inside the piston chambers of the engine. The engine takes those explosions and converts that energy into rotational energy. That rotational energy travels through the transmission and then to the wheels. That's what makes the car move. If an electrical car, instead it's powered by high-powered electric motors which use the relation between electricity and magnetism to create the rotational energy. As for electronics, the 1's and 0's don't inherently do anything to make the thing move, but they connect or disconnect circuits that operate control components. These components do stuff like regulate valves and ignition timing for combustion engines or regulate power throughput for electric vehicles."
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hsiv4l | What causes that delay on cellphone that you hear sometimes where you hear your own voice back a second or 2 later and how can that happen if your voice isn't being recorded and played back? | Technology | explainlikeimfive | {
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"fyaq0yg",
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"text": [
"Basically, lag and feedback. You talk, and because it has to travel to the other person's phone via a complicated series of telecommunications systems, it takes a second for the sound to come out of their phone. Then, the noise travels from the listening end of their phone to the speaking end, then it takes another second to get back to you. Your voice isn't 'recorded', it's more like an echo.",
"It's the echo -- one of the most hated and hard parts of any kind of (digital) telephony. Your voice goes full loop from your mic to speaker on the other side, then back to mic on their side and back to your speaker. Obviously, when other party wears headphones, it can't loop that much. On analog phones you just wire mic and speaker in way, that all output to speaker is canceled back on input -- does it to some extent when the gear is god enough. On digital, you have some kind algorithm to do is The Smart Way on a codec level. It never really works, especially when mic and speaker are driven by different clocks -- samples going in and out just don't overlap. Sound is also distorted, would always have added noises (other than your voice) while it travels in and out -- and you can't really split all of it back to individual harmonics and only cancel ones that you had received. Then you have added latency somewhere and can no longer get that something going back in through the mic is something you just fed to the speaker (because it was earlier). In a group call? It's even worse -- somebody would sure produce an echo, multiply echoes even, so you just mute everybody by default and talk in turns. On one-on-one call you could at least suppress your own echo when you receive it back."
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hsk1wf | Modern cars have parking assistance where it looks like a drone flies over it. It even works indoor. It even shows the surrounding in real, not just in outlines How does this work? | Technology | explainlikeimfive | {
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"fyavylx",
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"text": [
"Wide angle cameras are placed around the car. The cars computer then takes it all and puts into a single view for us to see",
"The car has cameras all around it, and the car's computer system warps the camera images to create an image that looks convincingly enough like an aerial view for it to be useful. For the car itself, it just uses a set image of the top of the car. The illusion is quickly broken if you have somebody stand right next to the vehicle while the display is on. You'll see the side of their body, not the top, heavily distorted."
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hskenc | Why it's common to have two (or more) graphic cards in computer, but there is always only one processor? Wouldn't it help to have two of them? | Technology | explainlikeimfive | {
"a_id": [
"fyayjw1"
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"text": [
"It is common to have multiple processors, they're just built into the CPU package. This is what \"dual core\" or \"quad core\" processes are. It's not uncommon for a modern CPU package to hold 16 independent processors. And actually, GPUs are the same, but on a much larger scale. They are specifically designed for doing many small tasks simultaneously, so they have hundreds or even thousands of processing cores. Adding a second GPU just adds a few thousand more of these. Also, 2-socket CPU configurations are actually quite common in servers."
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hslddh | Why do cheap quality or lower voltage chargers cause devices to heat up so much more than oem and higher voltage ones? | Technology | explainlikeimfive | {
"a_id": [
"fyb5dh0"
],
"text": [
"Different types of metal have different conductivity, gold is one of the metals with less conductivity, imagine using it for cables? Well cheap or low quality metals can be used to make cheap or low quality chargers. Also keep in mind that energy can’t be created nor destroyed, so it transforms into heat, possibly damaging the circuits and or burning plastic and or the silicone plate the circuit it’s mounted on."
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hsm8eb | Why were 4-speed automatic/manual transmissions so common in so many cars? What made them THE choice? | Technology | explainlikeimfive | {
"a_id": [
"fybby4o",
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"text": [
"It is possible to have 4 forward gears and reverse with only one layshaft and a reverse idler. 3F + R is even easier, only one layshaft back in the column days. To have 5 forward gears takes three layshafts. A 50% increase in parts for a 25% increase in gear ratios. This interesting [animated gif]( URL_0 ) shows how it works, minus reverse.",
"They weren't always? The Ford Model T had only 2 forward gears. Many cars from the middle of the 20th century had only 3 gears, and in fact 3 speed automatics were still common as late as the 1980s.",
"Gears are expensive. Decent ones are precisely machined and then hardened. So having more of them is more expensive. But having too few is harder on the engine. For a long time, 4-speeds were common simply because 3 gears didn’t give a good balance between torque during acceleration and a decent engine rpm while cruising. With the rise of computing and computerized machining, both automatic transmissions and gears got much cheaper to make. There was a phase where 5-speeds were decently common, but now a 6 speed automatic is probably the most common transmission.",
"Well it's just what was most efficient, semi trucks have 18 gears because that's what makes the engine run the best. The point of gears are to keep the engine within a certain range, the gears are just different ratios to keep the engine inside a good range of rpms, and different number of gears mean a better or worse range. I've seen 3 gears, 6 gears, 13 gears, 1 gear, it really depends on the engine"
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hspjfc | Why do some websites only work on certain browsers? Sometimes it’s only safari or sometimes anything but safari | Technology | explainlikeimfive | {
"a_id": [
"fybwabh",
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"text": [
"A web browser is a program on your computer that reads instructions, and uses them to draw things onto your screen. You can send a web browser any instructions you like, but it can only correctly draw using the instructions it knows. If a browser hasn't been programmed to know what to do when it reads a certain instruction, that functionality is unsupported in that browser. Web browsers are competing products, so each company is trying to add more features to their own browser. Sometimes they even create new instructions that only work in their browser, and no one else's. This is what Apple has done occasionally with Safari.",
"When you are accessing a website, what really happens is your browser download some sort of recipe that the browser can follow to create the website. The problem is, different browsers are created by different people. And when the recipe says \"put just enough salt\". They interpret it differently. And some browser doesn't even know what salt is. That's why. Oh yeah, sometimes the recipe owner only let a certain browser to use their recipe because they only test it in that certain browser. It could work on other browser but they don't want to take the risk because they do no testing on that."
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hspzsr | What happens if you turn a computer off while it says not to turn it off? | Technology | explainlikeimfive | {
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"Updates often have changes for operating system files. If the PC should lose power, some files may only be partially saved, causing system corruption, and potentially destroying the software. In such a situation, your only option may be to completely wipe the hard drive (losing all your saved information) and reinstalling the entire operating system completely. Do yourself a favor and let the thing do the thing.",
"Worse case? Corrupt the OS system files and you have to re-install Windows.",
"It depends but usually nothing too bad. Most processes that prompt this kind of message can be recovered from terminating abruptly if the process was well-designed. The software will journal its progress and if it fails or is interrupted, will be able to roll back its incomplete changes. Most OS updates are like this. This is usually followed by another long-running \"don't shut off your power\" process at next boot when it cleans up and checks system files. Some processes really don't take this well, though. Power loss when running something that modifies the filesystems or partitions on disk can result in data loss or a system that won't boot. Power loss while updating firmware is very bad. While some fancier devices keep a firmware backup, this is rare and without it, the device can be very hard to repair. At the end of the day, it's going to depend on what kind of operations are being done and how much care has been taken to make failures recoverable.",
"Computers have several ways to \"remember\" things (store information). One is what computer uses when it's turned on, were it does calculations and runs different applications. You probably heard that computers can do billions of operations per second, and for that they need to be able to access a lot of data, very fast, without unnecessary delays. All this is done in memory called Random Access Memory (RAM). Unfortunately, making memory fast means it's very expensive to manufacture, which limits how much you can store there. And the way such memory is made fast for truly random access creates a very severe disadvantage - it \"forgets\" everything if power is turned off. That is where another type of memory comes to help - long term memory based on various technologies such as hard drives, SSDs and other flash memories, magnetic tapes, or even cloud storage. All that other memory is too slow for a processor to use directly. Various programs that you run on your computer have different needs for this long term storage. Some, like games, only read most of the time. Except when you change settings or make a progress that needs to be saved. Other programs, like a video editor, would need to both read and write quite a lot. But remember, in computer's terms accessing that memory is very slow, therefore computers try to avoid doing that as much as possible. One way to speed things up is when applications don't write all they have to disk immediately, but wait for the user to \"save changes\". Another technique is to use \"disk cache\" - where part of RAM is used to store data that needs to be written to the long term storage so that applications writing that data \"think\" it's all written down and can get on with the main tasks at hand. The Operating System (Windows in your case) would then write that data from the cache to the permanent location, slowly, as a background operation. There is a logic behind when the OS decides to start writing that data, it depends on how full the cache is and tries to prioritize user's experience to make work with the computer feel smooth and fast. Sometimes, when a user decides to shut down the computer, the disk cache is not yet empty. That means that there is still data in RAM that is not yet put into permanent storage and would be lost if power is turned off. Whatever that data is depends on usage of the computer prior to shut down. You might end up with game save to be gone. Or it might be that nothing will be lost because it was some telemetry of the OS or log files of the apps that would not get written down, stuff that you don't need anyway. But something will be lost, therefore better wait and let the OS shut down gracefully."
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hsrvkj | How do trains work? Especially, how does the electricity flow between the power lines and the train, for example, while changing tracks? | Technology | explainlikeimfive | {
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"Trains run on DC, meaning that the one electrical terminal will always be positive and the other will always be ground. For trains, the positive terminal is the overhead cabling. The rails it drives on is the ground terminal. So when a train extends its boom and contacts the overhead cables, the electric circuit is closed. The rails are literally electrified. However, it’s safe as the are kept at the same potential as the ground you walk on.",
"The details of the power supply change per country. Most systems use 2 overhead power lines, a single overhead and a return through the rails, or a third rail and return through the normal rails. This can be done with AC or DC. When a train changes tracks it usually loses power supply for a short while. Batteries can be used to bridge the gap while switching to the new supply. Again, the details change depending on the location"
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hssra3 | how does the internet go around the whole world? | I have basic understanding of hardware. I get wifi, kind of... But like, shouldn't there be cables in the ocean to connect our continents? But that's so stupid. How is it done? | Technology | explainlikeimfive | {
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"There are cables in the ocean that connect our continents. Like 380 cables, over 1.2 million kilometers (745,645 miles) long.",
"There are thousands of miles of fibre poetics cable under the oceans, it’s nothing new, there’s been telegraph cables under the ocean since like the 1800s This video goes into the details of the history of the internet crossing the sea: URL_0",
"You're correct! It's actually all quite impressive, check out the below interactive under sea cable map [here]( URL_0 ). Edit: Interestingly, most cables are owned by many telecommunications companies at each end, however, there are some owned by single parties e.g Google! Edit 2: There are stats on each cable including date laid, ownership, length etc"
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hstf5x | I have a Reverse Osmosis water purifier and I've noticed that it has a pipe that constantly pours out 'waste' water. Why does it do that? | Can't it just purify all the water? | Technology | explainlikeimfive | {
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"The machine moves salts and other contaminants from one section of water to another. The “waste” water contains everything that was in the original tap water.",
"And do what with the impurities? The waste water is water that has everything just removed from the filtered water. That has to go somewhere, so it is dumped.",
"Osmosis is the ability of water to pass through membranes, but not other minerals or chemicals. If you have a solution with lots of minerals and another solution free from minerals, separated by a membrane, then the water will be drawn, or pushed, through the membrane until the stronger solution is diluted. Reverse osmosis uses extra pressure on the 'concentrated' side, the incoming impure water, to force this backwards, to force water from the 'concentrated' side to the 'pure side'. But the pressure you have to push with increases with the difference in concentration, impurities. If you just kept pushing water from the same pool through, the concentration of remaining impurities would get higher and higher, and the force needed to push against it higher. In addition, more impurities would get forced through with the water. So you have to keep the level of impurities in the incoming water low, which means constantly replacing and then dumping, the input water before the concentration of impurities can get too high."
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hsupps | how does a electronic weighing scale work ? | Technology | explainlikeimfive | {
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"There are materials that change their electrical resistance if they get stretched or compressed. If you attach strips of them to a metal bar, you'll be able to measure how much said metal bar bends. If you fix one end to a frame and put a plate for people to step on at the other end, people will slightly bend the metal bar.",
"There's a little doohicky called a [strain gauge]( URL_0 ). It's basically a bit of resistive material painted onto a thin piece of plastic, sort of like a printed circuit board. When it gets stretched or squashed, its resistance changes. It's about the size of a fingernail. You glue it onto the side of a block of something, then when you put a weight on the block, the block gets squished slightly, and the strain gauge can be used to measure the amount of squishing. For example, even insanely heavy things can be weighed using strain gauges. Make a big steel block large enough to hold the thing you want to weigh. Glue some strain gauges around the block. Roll the heavy thing onto the block and measure the change in resistance on the strain gauges. Fun fact: ordinary resistors (at least the carbon kind) will behave the same way, but they're not so easy to glue onto the sides of things, and probably not nearly as precise. Source: had a summer job working with the things when I was a kid. I soldered the leads onto them (tricky!) and then glued them onto the thing to be measured."
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hsur9y | How come forging doesn't seem to have improved since the metal ages ? | I'm a huge fan of "forged in fire" and it seems to me that technology hasn't done a great job of improving this craft. I mean except for things like a power hammer, how is it possible that we're not able to control a quench. There are so many "castrophical failures"from what seems to be competent bladesmith. I don't understand how in 2020 there are still variable in that process that we are unable to control. & #x200B; I'm french so sorry in advance if there are error in the text. | Technology | explainlikeimfive | {
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"Things like forged by fire and other hand crafted forging is more for the novelty than practicality. There are modern ways to make knives for example, but they don't make good TV shows or collector items.",
"> how is it possible that we’re not able to control a quench. We are, when we’re not being filmed for a Television show that needs drama to be entertaining. There are several liquids used for quenching in modern smithing, and very effective methods of maintaining quench temperature. > I don’t understand how in 2020 there are still variable in that process that we are unable to control. Artificial limits placed on the smiths by the creators of the show. One of my neighbors was on the show. He compared it to being asked to build a house, on a time limit, with access to only what you’d find in a Junior High School’s wood shop.",
"Metallurgy has come a looooooooong way since the metal ages, and has allowed us to understand how the crystalline structures form in metals and at what temperatures they exist. When the metal is quenched, the formation of those structures \"freeze\" at the stage they are in. However this freeze creates a lot of internal stresses in the metal because the behavior if metals makes them expand while being heated, and contract while cooling. If this expansion and contraction is too extreme, the energy between the crystalline structures forces the metal to break or shatter at the grain (boundary between crystals) where the difference is the highest. This is made more difficult to control in the real world than the predictive equations materials scientists use because there are always impurities in the material. Depending on how the impurities interact with each other, the core metal, and their concentration, they can make the boundaries stronger or weaker. And even in the most highly controlled forge with the purest of materials, there is just the simple issue of human error. Mistakes and accidents can just happen.",
"It seems like technology have not improved forging is because it makes for good rating on TV. We’re getting so good in metallurgical forging that it would became boring if we were to show the real metallurgical technology of 2020. We’re able to know the calculate to a close percentage the shrinkage during forging and since you mentioned quenching, we can do such precise case hardening that you’ll get a uniform thin layer of super hard surface while retaining the softness in the core. We’re talking about millimeter tolerances if you’re not too fussy about it.",
"Also remember it's a staged television show. The odds that things are engineered to fail for \"better TV\" are very high. Many of those failures could be deliberate.",
"Thank you all for your answers, I learned a lot !",
"Most metal working is automated these days. And there isn’t a great deal of demand for high quality knives and swords. Metallurgists get paid by other industries: guns, cars, aerospace, chemical engineering."
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hsvede | Has photorealism / hyperRealism in art always been possible? If not, what changed? | It seems that old masters also tried for realism. Is that not the case? If they did, how have people gotten so much better at it recently? | Technology | explainlikeimfive | {
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"Its always been possible to some degree. However, photorealistic art wasn't considered appealing in the art world until relatively recently. And many artists still hate photorealistic artwork because its seen as lacking creativity. As counter intuitive as it sounds, its easier to draw something that is highly realistic and looks appealing than something that is surrealistic/abstract and appealing. Picasso originally started out drawing realistic artwork, but over time shifted to a surrealistic/abstract art style as he got better at it.",
"Yes, Roman art - such as sculptures and mosaics - is well known for being photo realistic. Producing photo realistic art requires the artist to be a professional artist. That is, someone who can train and work as an artist full time. That's not a big deal in the modern world because art supplies are cheap - even people living in extreme poverty are able to afford them. But it was a particularly big deal in the pre-modern world because the supplies that you needed to practice, such as paper or stone, were expensive - so much so that a national effort was required to support a handful of full time artists. This is why art loses its photo-realism in between the Roman collapse and the Renascence. Both the Roman Empire and Renaissance era Italy had economies that were capable of supporting full time artists who had sufficient supplies to enable them to practice. Dark age and medieval Europe did not. The vast, vast majority of people who were producing art during those time periods were monks. Those monks were basically professional bible readers who worked as part time scribes who would occasionally doodle on the manuscripts they were working on. The very limited practice that they got meant that their drawings were fairly rudimentary. Where there was the occasional noble who could afford to have a painting commissioned there weren't any professional artists to commission it from and the best they could do was one of those monks."
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hsvm4m | Why are photos and selfies different from real life? Is the mirror more accurate? | I notice this with myself and others. For instance, my face shape looks different in a selfie than in the mirror (or apparently real life according to other people). It's really unflattering. Why does this happen? | Technology | explainlikeimfive | {
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"Firstly, there is the fact that the mirror is reflecting your image. As this is the version of you that you see most often, it tends to be the one you prefer (due to something called the Mere Exposure Effect - we like familiarity), rather than the unreflected image in a photo. Then there is the effect of the lens. A standard camera lens will be relatively wide angle, so, especially when taking a picture at short range like in a selfie, will result in some distortion. The centre of the face will bulge a bit compared to the outside - you may even see that your ears are concealed by your cheeks, which does not happen in the mirror. Professional portrait photographers will capture their subject from a greater distance using a zoom lens, rather than shooting up close. This reduces the distortion, and better shows the accurate proportions of the face.",
"When you look in the mirror your image is reversed. Photos of yourself may look weird to you because your image is the reverse of how you usually see yourself. In the same way a familiar drawing or photo might look weird, or you might notice different details, if you put it in an image editing program and do \"flip horizontal\"."
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hsvpkw | Whats the difference between OpenAI vs DeepMind? | Technology | explainlikeimfive | {
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"Deepmind is a company owned by Google (well, really Google's parent Alphabet Inc). OpenAI is a company owned by a non-profit corporation called OpenAI Inc. Like Ford and Toyota, they are companies producing products in the same space."
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hsxmwb | if everything is registered in computers and databases, why do fake passports still work? Should they fail on arrival when read thru the machine? Like a 404? | Technology | explainlikeimfive | {
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"Because as example the US customs does not have access to the \"British citizen passport database\". The data on the passport is the same as the written one, including error correction keys and nowadays some biological data as well (such as fingerprint). It also depend on the issuing country and how old your passport is. All they can do is check that it's correct and matches you as a person. And cross reference with their own data of persons denied entry etc. TL;DR; there is no secret world wide database with everyone's information for them to connect to.",
"There are two kinds of machin-readable data in passports -- first is MRZ, that thing on the bottom of the front page in block letters starting with P. It's basically just a copy of all the standard information -- name, last name, nationality, birth date, issue date, expiry date and document number. This data allows to check person's identity through various black and red lists -- like interpol, restrictions on entry/exit or whatever. Lists that the country you are entering or leaving keeps. You could print whatever shit you want there. In the year 2020 EU still doesn't have a database of entry-exit events to automatically catch overstayers who break 90/180 rule Then there is the chip. It's usually called \"biometric passport\" with that rectangular symbol on it, but having biometric info, like fingerprints, iris scan or high-res digital photo is not the main point of it. Nobody really checks fingerprints against the passport on every-entry exit and photos are reaaly subjective to check against. The main point of biometric passport is the fact, that very same data that is printed in block letters is also included inside (with the photo) and *signed* digitally. So having access to the country's public key, you can be sure that information in there in authentic. That needs an explaination of assymetryc cryptography and public key infrastructure, which I won't give here. The problem however -- such information, while not being fakable still can copied, so there could be two (or hundred) people having *same* passport in different places. Or it could be stolen, which works too. They should look similar enough, but that's workable around. Or you could fry the chip in microwave or stupidly sign the data with wrong key and officer would likely shrug it over, because whatever -- this dumbfuckistan can't issue a passport properly. A fucking shiiit-hole, sir. Another issue with fake passports -- they are not necessary fake, but sometimes are just fraudlent. As in real, but with fake data -- somebody bribed or tricked authorities into issuing one by impersonating something else or inventing persona, using fake birth certificate (fun fact -- you could use birth certificate issued in one country to get identity documents and citizenship rights in another and same problem with cross-check applies. then don't have chips or photo too). Sometimes the state issues them to their own special services on purpose. Sometimes blank is \"lost\" or deemed defective but then sold on black market. Some countries have black-lists of revoked and stolen passports published, but nobody checks against them on the other side of the world anyway. There is no global database of passports or any kind of cross-checks between countries. Not all countries even issue biometric passports and not all of the countries routinely verify them properly. Obviously, when somebody is closely investigated or randomly caught up, there is more time to dig and check whether the documents are authentic, including asking the embassy of issuing country, but on routine border checks or plane boarding, it's often up to \"this looks legit\" kind of check. There is also more time when passport is submitted to the embassy for a visa. And you can't really expect underpaid border agent to know what real passports issued in the last 10 years by all of the 200 countries in this world look and feel like. In places other then border crossing -- every officially-looking piece of plastic shit would get your through ninety-nine percent of the time. All of this is also why one sometimes needs a visa. Every country trusts it's own system better then other countries systems. This is also why one sometimes doesn't need a visa -- level of trust into document issuing process is high enough and passport itself is as good enough as visa.",
"One thing I see missing from the explanations here is the concept of a \"checksum\". Many forms of ID / important numbers (including your credit card numbers) use part of the number as a way to validate the rest of the number, which contains the actual information. For example, take a hypothetical shortened credit card number of 1637 2827. One simple way to use a checksum would be to say \"add the first 7 digits together. The ones-digit of the result should be the 8th number\". The first 7 digits of this example add up to 27, and the 8th digit is 9. 7 is not equal to 9, so we know this card number is invalid. But 1637 2627 would be a valid number, as would 1637 2829. This is a very efficient way to validate a number, if you know the rules the number should follow, and it doesn't require any connection to the internet or a database. The rules are much more complicated than the above example, to make it hard for just anyone to create new valid numbers, but if you know the rules you could do it. So clever people can create fake passports and other IDs that scan like the real deal, even if they're fake, but it's hard enough that not just anyone could do it.",
"If you just want the passport to go drink at a bar, the bar doesn't have access to the database. Neither do countries other than the issuing one. In many cases, intelligence services that want a fake passport don't make a fake passport. They make a fake birth certificate, preferably from a town where the \"database\" (aka a basement full of physical, never-digitized paperwork) burned down, and then get a real passport issued.",
"In addition to what everyone else has said, there is virtually no likelihood of a worldwide checkable database ever. For instance, there are countries that, if you have a record of visiting them, lots of other countries won't let you in, due to political discord between them. (I believe Israel is an example). Well, those countries can't afford to stop having visitors, so they don't stamp your passport, they give you a separate entry approval paper on the way in that you have to keep and show on the way out, and then you can \"lose\" it. So they are not going to leave a trail of accessing passport data for visitors. Most countries in the world are not really \"friends,\" even ones that let each others' citizens in, that's more strategic alignment of interests than friendship. They don't trust each other enough for access to each others' citizens' data on a mass scale.",
"The reliability of any system lies in it's weakest link. Introduce a vulnerability or voluntarily allow an exception and now you have a very flawed system. Example : if there is a way for special agents / spies to get fake IDs, then the very same process could be used by other people in other circustamces.",
"I lived in a South American country for a few years until corona lockdown hit. My lawyer told me that until recently, the computer databases at the airport weren't fully connected to the information at the ministry where everyone got their visas. My visa was electronic, printed out on a separate paper, and I had to tell the airport customs guy my details verbally every time so he could figure out how my passport stamps matched up. So yeah... a lot of countries aren't even linked up within their own borders.",
"A passport is just a document that identifies who you are and what country you belong to, and certifies that you are exiting said country legally (That's why you get your passport confiscated for certain crimes). Foreign countries don't have any information about you to check your passport against. The best they can do is verify that the passport isn't fake since passports are standardized when it comes to anti-counterfeiting features. Biometric features can be checked against a checksum on the passport itself, which is definitely the hardest security feature to check. That's the best any border agent can do. Plus, not every country/point of entry in the world is even equipped to check the passport's digital features anyway."
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ht5agg | I often hear how scary and dangerous Biotechnology (gene manipulation etc.) is or will be. Why is it that? What is so scary about it? | Technology | explainlikeimfive | {
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"Normally I am just an observer, but this is a topic that is important to me. The truth of it is it is no scarier than traditional breeding methods such as selective breeding. The process that got us dogs from wolves. In fact many modern biotechnology products are safer because we have more control over what changes we are making, rather than making a bunch of random changes until we get something we like. The true reason it is so scary to many people is because they don't understand it, and we fear the unknown. Asking questions, and being willing to listen to people who spend their lives studying a subject, is one of the best ways to end the stigma against biotechnology. It is a tool just like any other. It is highly regulated, and a more controlled version of traditional breeding methods that go back 1,000s of years."
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htaujp | Why/How do programs get signed? | I'm a novice programmer and have been seeing around the internet this concept of signing an application. IRL, signing documents is vital to make sure some is legit and not a forgery and these signatures are unique to each person. In the computer world I assume it is to make sure that the program you are running is from a reputable source and wont run malware. What I'm interested in is how that is foolproof. It seems that if a digital signature is just an alphanumeric string, couldn't someone replicate it easily as alphanumerics are not unique to a person? Also how is the signing process done, is it similar to encryption? | Technology | explainlikeimfive | {
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"Very similar to encryption. The operating system contains a collection of “root” public keys linked to the private keys of certificate authorities. The OS provider then encrypts these keys against their own private key. When someone signs an app, they sign it using a private key that is in turn signed by one of these authorities. Signing is essentially encrypting the checksum of some important part of the program. So the OS/end user can then use the public key that’s been authenticated by the OS to decrypt the checksum and compare the result against freshly checksumming the same data. Signing is not just limited to apps either; this same technique is used for signing digital documents, network sessions, DNS lookups, email server connections, and much more."
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htbgkq | what's the difference between a pointer, reference and an array variable? | I mean I just started with C++ and they All look the same and it's so confusing. And sometimes a pointer is being initialized to a reference and sometimes an array is similar to pointer, I mean what's the point of other two then? | Technology | explainlikeimfive | {
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"A pointer points to a memory location. A reference refers to to the value of a variable, and an array is a list of variables. a = 4 b & = a c* = *a A is a variable which equals 4. B is a reference to the value of A, if you change B you also change A C is a pointer to the location in memory to where A is stored. If you change C it points somewhere else but does not change A. d[] = {1, 2} D is an array, it stores a list of values. Hopefully this formats alright from my phone.",
"Pointers and References are incredibly powerful C++ tools, but they can take a hot second to get used to so here's a somewhat short explanation. & #x200B; A helpful way to think about pointers is that they are an address. A pointer is an address to some location in your memory, some call it, a memory address. A pointer is indicated by a \"\\*\" on the left-hand side of an operation such as: int a = 5; int \\*b = \\ & a; Here, we assign the value 5 to a, and then we assign the address of a (using the reference operator \" & \") to b. What's important to know here is that the address of a is NOT the value 5. if you did a print on b, you would not get the value 5, but rather the value of the address, which would look like this: std::cout < < b; result is: x7ffee9af7768 and that is most definitely not a 5, it's a memory address, in fact, it's the memory address that holds the value of variable a So if you want to access the value located at the address that b holds, you would do it like so: std::cout < < \\*b; result would be: 5 that's because by using \\*b, you ask specifically for the contents found at the address that b points to. To further see this in action, you can try something like this int c = b; That will result in an error, because the above address is definitely not in integer format (its hexadecimal). BUT if you did this instead: int c = \\*b; now it works, because when the \"\\*\" appears on the right hand side of a statement, it acts as a deference operator. Basically, \\*b means \"give me whatever value is stored in the address pointed to by b\" & #x200B; Why is this so useful? Because it gives you more control! C++ works with pass by value and pass by reference, and pointers are how you choose which one you want! so if we make a small function to increment an integer by 1: void test(int a){ a++; }; and we pass it our variable a like so, test(a). When you print a, the value you get back is not 6, its 5. This is because of pass by value, our test function made a copy of the value, and worked with that copy, so our original variable wouldn't be changed by anything inside test. However, if we instead let our function accept a pointer, or an address reference directly like so: void test(int\\* a){ (\\*a)++; // take the value found at the address that a holds, and increment by 1 }; when we try out our function with our pointer now by calling test(b), our function doesn't make a copy, it's instead using a reference, and as a result, any changes test does to the variable, will be seen outside the function. So now, if you print a or \\*b, they will return 6. There's actually a LOT more to pointers than this, but if you just started with C++, this should be fine for now.",
"You're in a theme park. A pointer is the helper at an information kiosk who not only tells you the location of what you're looking for but takes you directly to it. A reference is the coordinates on the map. An array variable is just a pointer that points to the start of a queue",
"Pointer - memory location. Think of it as the address to your house. It doesn’t represent the house, but tells you where the house is. Variable by reference - passing a variable into a function/method/procedure by sending in a pointer to its memory location. In many languages means its value can be altered inside that function/method/procedure. Array - pointer to a memory location for a list of variables. Those variables might be strings, numbers, or other pointers. Generally arrays are allocated as a block of memory big enough to hold the type of variable it will hold times the number of items it can hold.",
"I assume you've heard of a memory address before. A pointer is a variable that holds a memory address. Or the address itself. (Like how we say \"x is 5\" even though x is actually a variable which is holding the number 5) A reference is a pointer with a different syntax. References were added to the language, because in order to have operator overloading, they needed a way to use pointers with non-pointer syntax. Otherwise you'd need to write ` & a += 5;` instead of `a += 5;` in order for the custom `operator +=` to be able to change `a`, and that would be weird. Language lawyers will get mad at me for saying this, but it's true. An array is a group of numbered variables, and you can access them by number. They're completely different to pointers and references. The only relation is that *if you use the array variable in a place where an array variable doesn't work*, the compiler automatically converts it to a pointer for you - you wrote `a` but it actually compiles as ` & a[0]`, i.e. the address of the first thing in the array. This is just for convenience so you don't have to write ` & a[0]` every time. Also, functions can't take arrays as parameters. If you *try* to make a function with an array as a parameter, the compiler changes it to a pointer parameter. `void f(int a[10])` is actually `void f(int *a)` in disguise. That was a silly decision they made a few decades ago, and it's too late to change it now."
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hte38o | What is "Inverter Technology" and how does it reduce electricity consumption/bill? | Technology | explainlikeimfive | {
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"answer : Are you referring to this ? URL_0 An inverter is an electronic component that changes Direct Current to Alternating Current. In the example I linked above, they compare 2 types of airconditioning. Type 1 (the non-inverter) runs on AC derived from the electricity grid. This means that it can only ever run at one constant frequency (you can't exactly turn the entire country's electricity grid faster and slower). Type 2 (the invertor kind) takes that AC that comes from the electricity grid, turns it into DC Power, and then turns that DC power back into AC power. However, because it's a smart invertor, it can output a range of AC frequencies. This allows the invertor to control the speed at which the AC operates. The energy saving manifests in that an invertor type AC can run at 50% cooling, while a non-invertor AC has to turn ON and OFf all the time."
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htf98j | how does “local play” on the Nintendo switch work? How can I play “online” with someone if I’m not actually online? | Technology | explainlikeimfive | {
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"It sets up an ad-hoc WiFi network just between the two devices. WiFi is just another form of local network connection, it doesn't necessarily have to have any internet connection involved.",
"Wifi antennas can send and receive. Most home networks use a \"star\" pattern where theres a central hub (your wifi router) and all the devices connect through that. Star pattern is the most common type of network, but it's not the only one out there. Nintendo switches can set up a \"peer to peer\" wifi network that connects the two devices directly together over wifi. You dont really need an internet connection to play with someone next to you. Just a local network between you two."
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htfan2 | why some websites don’t let you remove your payment method? | Technology | explainlikeimfive | {
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"Subscription services don't make sense for you to have an account but not pay for the service. How are you using Netflix and not paying them for it? Even if you wanted to suspend or deactivate your service temporarily (travelling, hospitalization, etc), you will still need to start paying again afterwards. From the service's standpoint it makes sense to just hold onto the payment information until you return. For the user's convenience. Really. So if you're going to stop paying, then clearly you intend to leave the service, right?",
"The question has already been answered by others, but I'd like to add: there are many services out there in which you can use a fake *virtual* credit card number that is tied to your real credit card. Therefore even if you have the payment method tied on file with that service, if they are hacked or experienced some sort of major breach of their security, only that virtual card number has been compromised. Then all you need to do is update your credentials on that service so that a different and new virtual fake credit card number is used instead -- destroying the link that ties your real credit card to that previous fake number. For one of many examples, Google Pay has this built-in. You might have a card ending in 1234 tied to it, but it reports your card to merchants as something entirely different, like one ending in 5678",
"Honestly, the good answer is simply that their software is not as sophisticated as you think. Tech itself may seem glorious with cool buzzwords like 'Top tier system with excellent security and enhanced AI' but alot of the times, basic functions like deleting link to another entity is not possible. Thats just how some systems could be. Of course, it could be hard to get a real answer unless someone from the implementation team answers your question, which is technically impossible as they probanly cannot reveal project details. But just my 2 cents."
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htg4jq | Why are news websites (esp local) so horrifically painful to use? | Is there some explanation for how they got that way? Stuff like pop-ups, the page jumping around when you're trying to read the article, ridiculous paywalls, improperly implemented paywalls, the whole page absolutely littered with ads... It seems the rest of the internet figured out how to make a website, but local news sites just *cannot* make something user-friendly. Is it just a money thing? Or is it that they're failing to adapt to having social media as a competitor and this is what a slow death looks like? | Technology | explainlikeimfive | {
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"Money. All those ads are how the consumer pays to use their \"free\" site. The bigger problem is that in an attempt to make what little money they can, they don't pay the web developer enough to make sure the site is as \"smooth\" as possible. Add that to how often the site has to be updated to keep current, and you get the mess that free news sites are (maybe even pay sites, but I've never paid for a news site so I cannot confirm)",
"As said above, money. There are two revenue streams for online news: subscription and advertising. Subscription revenue is having paying subscribers. Many local news sites WANT this, but it's hard given that everyone on the internet is used to things happening for free (social media being a good example). So those sites rely on ads... Advertising revenue is broken into two streams. Direct sold and programmatic. Direct sold is likely locally based and they pay much higher rates (think a local sports team advertising a big match). These are less common, but generally more enjoyable for users. With the pandemic, no small, local business owner is willing to advertise right now... So we get... Programmatic ads are served by Google, Facebook and amazon. They are tricky to implement in order to make enough money without affecting user experience. Most non-technical staff at news orgs think you should just add more in order to make more. Source: have worked for a news org on their digital team",
"The local newspapers are being collected and purchased by larger groups. I find it hard to believe that a company that owns many newspapers has no idea how to correctly build a website. It feels like we are being herded to view our news on select news sources. It’s just how it feels. 🤷♂️",
"For my local newspaper it seems to be a combination of fairly average web admins who are probably just stringing together a badly managed mess of Wordpress (or similar cms) plugins, with little actual dev ability to make things work together better, as well as a desire to make as much advertising revenue as possible. My one even has all those dodgy click bait titled ads all over the place."
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hthsk7 | Why do code systems have to be "maintained"? What happens that part of it suddenly doesn't "work" anymore? What causes a "bug" in the system? | I have no background knowledge whatsoever, so please forgive me if I'm not using terms correctly. This was prompted by a popular story I read on Reddit about a guy who designed a program to monitor the machines in a factory, was eventually let go, but then begged to return because the program wasn't doing its job anymore and he needed to come fix it. Why and how does this happen? | Technology | explainlikeimfive | {
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"Code, unlike physical objects, does not rot or \"go bad\" What typically happens is that software needs to change. Reasons for change include things like, we need a new feature, or we need to change how something works. When adding new or changing old features, it is very common to \"miss\" some aspect of how the original code works - this leads to bugs. A bug can be as simple as hey we forgot to carry over the decimal part of this number, or hey, this button needs to be lit up under these conditions, etc. In the case of systems written poorly it is often hard for a person to get a good enough grasp of how things work to avoid these sorts of bugs. In more dastic cases, maybe no one can make heads or tails of how things work. In these cases you Might need a really good programmer - or the original (bad) programmer to make sense of things.",
"Most modern code typically relies on shared libraries. These libraries tend to get updated against security vulnerabilities. Operating systems as well. This will sometimes lead to breakage. Additionally, over time requirements for what the code is supposed to do changes and that can also lead to the need for maintenance and updates. Many times companies find themselves with poorly documented code/systems where the individuals responsible are long gone. It's sometimes easier to try to get these people back to fix the problem than for a new person to try to figure out what's going on. Especially if downtime leads to lost revenue.",
"There are countless possibilities. Perhaps the best known historically is the so-called \"Y2K bug\". A lot of computers used two digits to denote the year instead of four, so people were afraid that when we hit the year 2000, every computer would start thinking it was 1900, and we'd be plunged into varying degrees of anarchy and chaos, depending on which news outlet you were reading. It's possible that the person in your example designed the program to monitor a certain kind of machine, but then the factory upgraded and the new machines used different communication protocols. Perhaps he was in the habit of downloading records of some sort from the computer and storing them elsewhere; with him gone, the memory could have filled up and the computer didn't know what to do. Perhaps he failed to tell it what to do when daylight savings time came around, so it thought it was an hour off. Perhaps he simply wrote it poorly; the computer encountered a set of circumstances he had never anticipated and so never told the computer what to do in that set of circumstances.",
"The people writing (programmers) the code are meeting requirements that the program needs to do, then monkeys (software testers) are thrown at it to examine and beat it with hammers to make sure it's doing as the requirements state. Then you have the people (stakeholders) who asked for that program come back and say they want something new added to the stable code. Writers do as they're told and the monkeys test the change to ensure it isn't affected negatively by the newly introduced code. Ultimately, they find nothing that affects it and push the change to stakeholders. Stakeholders love the software, but manage to find bugs that the testers didn't account for, causing code review and testing to figure out what change made the bug. TLDR: Software can be made stable, but introducing changes without testing fully and releasing it into the wild will ultimately come back to bite you."
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htjiyw | If I have 500gb/s internet speed and want to download a 100gb game, shouldn't I be able to download it in 1/5th of a second? | OBVIOUSLY this isn't how it works, but I honestly have no idea what it means for me to get 500gb per second and how that applies to real life. | Technology | explainlikeimfive | {
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"It's a sly advertising method they use; it's gigaBITS not gigaBYTES per second. In terms of label, there's a technical difference between the lowercase gb (gigabit) and uppercase GB (gigabyte). A byte is 8 bits; a gigabyte is 8 gigabits. Assuming the internet speed is actually performing at 500gb/s, it's going to download 62.5 GB/s and take about 2 seconds to actually download. But that assumes that you're actually getting the advertised speed of 500gb/s - it's \"better\" to run a speed test and find out how fast your connection actually is, because it *probably* isn't going to match what you were sold. There's dozens of factors for why you might not actually get the 500gb/s, like if it's prime time and lots of folks are on the network impacting traffic, there could be a hardware issue somewhere between you and the ISP, the server you are trying to connect to might only output 50gb/s instead, etc etc etc.",
"Your connection speed is most likely 500 **MEGA**bits per second. Not **GIGA**bits per second. That's a thousand times slower. The connection between your computer and your router is probably around 1 gigabit. Nowadays maybe 5 gigabits, maybe 10 if you have a very powerful computer and router and network. As others have pointed out, download sizes are measured in (giga)bytes, not (giga)bits. 8 bits per byte. So your 100 gigabyte game amounts to 800 gigabits. A 500 megabit internet connection speed translates to approximately 0.5 gigabits per second. Assuming every single point between you and the download server can support this speed, you will end up with a 200 second (3.3 minutes) download. In the real world it's most likely even slower.",
"If the server is capable of uploading at 500GB/s *and* every cable, router, switch, etc. along the way can handle the speed, then it can get to your PC. But of course your PC would also need the hardware. No network card in existence can do 500GB/s of course - the PCIe bus they use to communicate with the rest of the computer \"only\" does a few tens of GB/s at most. You wouldn't be able to write if out either: the best drives on the market can do 1% of that speed and even writing to server grade RAM (as RAMDisk/tempfs) can only do ~100GB/s. Of course this precludes the server being able to upload at that speed.",
"500 gigabit The game is 100 gigabyte A byte is 8 bits. Your game is 800 giga bits Finally. Your internet speed is only as fast as the slowest point. If your game is behind a server on 10gigabits/s connection. It will take a while.",
"Yes, that's exactly how it works, theoretically. Note several things though: 1. Download sizes are usually in gigabytes, while network speeds are in gigabits. 1 byte is 8 bits, and there's overhead on top of that. To account for that, overhead and other minor inefficiencies, 10 Gbps = 1 GB/s is a reasonable rule of thumb. 2. You need everything in between you and the source to support those speeds. So if you can download that fast, whatever you're downloading from also needs to supply it at least that fast too. That's probably true for Steam, but not necessarily true for the website of small indie game makers. 3. The above includes your own networking equipment. Your routers, switches, and computer must support fast enough networking. Currently consumer tech has a top of 10 Gbps, and 1 Gbps is still common. You can go faster, but it takes high end, special hardware, or doing things like bonding (multiple connections acting as one) 4. You need a computer and disk system capable of writing data that fast. A hard disk can do somewhere around 100 MB/s, and often a lot less. For really ridiculous speeds you want a NVMe drive, which can write at speeds of 2-4 GB/s depending on whether it's a PCIe 3 or PCIe 4 one. So, with current consumer tech, 1 Gbps internet is very doable, and 10 Gbps is rare but possible. With a NVMe you can get the required disk performance, so technically today you could download games at 1 GB/s, given a modern computer, a NVMe drive, and an expensive internet connection. It's quite up there, but not crazy rich territory either. Somebody really motivated, and with access to an ISP capable of providing such speeds could do it. The price for a 10 Gbps connection currently is $55/month in Japan, $250/month consumer level in the US (one I just found), or thousands of USD per month for enterprise level service.",
"Check out the difference between 1Gb and 1GB. That's only one factor that is commonly misunderstood about internet connections."
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htkphl | How is an Operating System created? | Technology | explainlikeimfive | {
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"Creating an OS from scratch is a lot of work. This is much more difficult than creating an app from scratch owing mostly to the lack of tools to use to create the OS. Linux was not created in a vacuum. Linux was trying to mimic an already existing OS, Unix. It had the advantage of only needing to support existing APIs defined by a well-defined standard (POSIX). But to the question. The first challenge in building an OS is getting it to start. Usually when an app launches, the OS launches it. What launches the OS? How does it startup. This process for legacy reasons is called bootstrap, where the OS launches itself. Where do you build the OS if not on the OS in question? Normally when building code you develop it on the same platform as you are running on. Building a PC app your buidl your app on your PC. So you have to do something called cross compilation where you build your code on your development platform then move your code to your bare metal machine you are trying to launch your new OS on. Then you get to worry about the larger topics of how to programs interact w/my OS and what services will my OS try to provide to said programs. And then it gets complicated beyond what I can cover in an ELI5"
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htma4n | How can some cell carriers have coverage in certain areas while others don’t? Do they all have separate physical towers? If so, how do small companies have coverage? | Technology | explainlikeimfive | {
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"Yes, you’re correct. More specifically all the big companies own at least some of their own towers. Others are privately owned and the cell companies lease space put to their own antenna on it. Multiple companies can have an antenna on the same tower. Smaller cell companies usually lease the use of larger companies networks, but their traffic is deprioritized or speeds downgraded. With the coming of 5G, leasing space to put up an antenna is more and more common because the range is low. Cell Companies lease space on the rooftops of commercial buildings for example, for 5G antennas.",
"FYI, in the United States, there are really only 4 carriers that provide cell service: Verizon, AT & T, Sprint and T-Mobile. Actually there are only 3, as Sprint and T-Mobile have merged. AT & T and T-Mobile use a radio technology called GSM, and Sprint and Verizon use one called CDMA. They are not compatible, so a Sprint phone won't work on the AT & T network. At least that's the way it used to be. With combo CDMA/GSM phones, and with LTE, this is becoming less of an issue. Each major carrier is considered a post-paid service. Each carrier has a subsidiary that offers pre-paid service: Sprint has Boost, AT & T has Cricket, etc. Pretty much every other (national) cell company is a MVNO (Mobile Virtual Network Operator) that buys service from one or more of these 4 major carriers and resells it: Ting, Mint Mobile, Straight Talk, Consumer Cellular, etc. There are a few regional companies that operate their own regional cell network, but these are an exception. So since these MVNO companies are really just reselling service from the big 4, that is how and why they can have national coverage."
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htmf0v | How do companies keep creating new and improved components for PCs consistently every year? | Is it all planned obsolescence or what? | Technology | explainlikeimfive | {
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"Transistors keep getting smaller. It's called [Moore's law]( URL_0 ), basically every two years or so computers become twice as fast because we can fit twice as much processing power into the same space. That extra processing power can be used for better graphics, quicker speeds, more useful software, basically everything. It isn't planned obsolescence any more than the fact every few years they can make faster cars.",
"Kind of planned obsolescence, whatever’s released that’s considered NEW TECH they’re already beta testing the stuff that’ll be released within the next 7-10 years or so. An example that I’m betting on is a a thread I saw where it predicts that holographic tech will be revealed around 2028."
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htnro5 | Why computer scanners have to "scan" the page? Why there is no scanner that works like a camera, you place the page on the glass bed, close the lid, snaps the image like a camera and done. Isn't that much faster? | Technology | explainlikeimfive | {
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"There are ones like you described. Your phone can even do it. But the reason for using scanners with a bed of glass is to get the best quality. It ensures even light and completely flat with perfect 90 degree angle. Capturing the highest resolution by going slowly illuminating the whole page evenly.",
"Commercial imagers work this way. It’s just way more expensive to make a high megapixel photo sensor that can capture the entire image at once, so scanners use a smaller one and move it over time to build up high resolution images.",
"Such a camera would need to have an image sensor with a HUGE number of megapixels to compare it to a scanner, plus you'd need some kind of lens or else the scanner would have to be a lot taller so that the camera would have a good view of the whole page at once. The perspective of the camera against the paper would need to be corrected for as well. Also the light source inside the scanner would have to be very even across the whole page. Basically there's a lot of logistical issues to be solved. Look at the resolution issue by itself. For 8.5x11 inch \"letter\" paper at 300 DPI you get an image of 2550x3300 pixels, or 8.4 megapixels. Such cameras are common, but 300 DPI is kinda low resolution for a scanner especially if you want to do photographs. At 600 DPI it becomes a ~34 megapixel camera you'd need and it only gets worse from there. A lot of costs and size can be reduced by having the scanner just be a straight line that moves across the page and pulls in the image that way. Finally, if you're scanning a document made of many pages, you have to move the pages aside one by one anyway as they're scanned. It's not that big a deal to just move them over the scanner's sensor as you're flipping through the pages which is what photocopier-type scanners do."
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htq8aj | Why do old tv shows have such bad quality compared to old movies? | TV shows and old sports games from the 90s and early 2000s have such bad quality, like you can count each pixel on the screen, when old movies from decades prior have quality similar to what we have today, why is that ? | Technology | explainlikeimfive | {
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"Probably from being digital. Correct me if I'm wrong, but it's a hell of a lot *easier* to 'remaster' and update old footage taken from film, rather than digital/tape or whatever."
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hturcp | What is 5G? Why is it supposed to be so dangerous? | Technology | explainlikeimfive | {
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"5G is the newest radio frequency that will be used for cell phone networks. Like 3G and 4G before it, it's just another frequency, there's nothing really special about it, other than it's higher frequency than 4G, which means you have to be closer to the nearest tower, but it will provide much faster maximum speeds and bandwidth than 4G is capable of. As far as why it's \"supposed\" to be dangerous, that's primarily due to fear-mongering by people who don't understand the technology, or who are actively lobbying against it for some reason. The belief that 5G is dangerous is in the same school of thought that purports that talking on a phone will give you brain cancer, or that keeping one in your pocket will render you infertile. The idea comes from the fact that the electromagnetic radiation from the phone is somehow dangerous to human tissue, even thought that's never been proven in any study (that I know of). The amount of energy put off by your phone is very small, in comparison to other common sources of EM radiation you encounter on a daily basis and is harmless. Some people also believe that wifi routers cause cancer, for the same reason. It's paranoia and fear of the unknown, not valid, science-backed concern.",
"5G is the successor to the previous communications standard, 4G. It is much faster but shorter range than the previous standard, and requires more infrastructure to be built to support it. The \"dangerous\" part is difficult to quantify. The problem comes down to there being a relatively vocal subset of the population who are functionally insane. Lacking the appropriate mental care to deal with their delusions they view the construction of communications infrastructure they don't understand as a personal threat in some vague, ill-defined way. Maybe they think it will control their brain, maybe give them cancer or their children autism, perhaps they believe it somehow creates or spreads coronavirus, or any number of far-fetched ideas. What exactly the danger is can vary widely between those holding the belief."
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htwr4h | What is Django actually used for? | Technology | explainlikeimfive | {
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"It's a framework. So imagine you're writing a website, and you're making a simple login form for someone to log in to an account. You could start from scratch, but then you'd have to worry about minor details like: organizing your application files/page templates and such, XSS exploits, CSRF attacks, other best practices, all of which are necessary to make a good and secure login page, but it's really repetitive obviously, every single website is going to need all of these things, and you don't want to waste all of your time rebuilding these every time you make a new website (and risk making a mistake) - you'd rather spend the time writing the more interesting code that does whatever it is your website is actually meant to do. So a framework handles all of this stuff for you, basically. So for example, instead of writing all of the code for generating and checking a CSRF token, for example, and risk making a mistake, all you have to do is insert a simple ` < form method=\"post\" > {% csrf_token %}` tag in your template, and an equally simple function to check the token's validity, and it handles it for you.",
"For making websites. It is a framework that handles a lot of the nitty gritty things webservers have to do so that you do not have to reinvent the wheel and can jump right in to making the site you want. It has a particularly powerful database model that allows you to easily manage a really complicated relational database with ease as if it was just a series of python classes representing the objects of the database. You can use it both for the front end and the back end and it makes full stack web development quite a bit easier."
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|
hu193d | How can cameras take videos with 24 frames per second while having a shutter time which is far longer than 1/24? | Technology | explainlikeimfive | {
"a_id": [
"fykc05h"
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"text": [
"OP, which camera do you know of that has this functionality? I'm not familiar with any that can do it--the only way I can imagine it working is with digital processing--taking much faster images and compositing them to make an effective (1/6) of a second shutter speed....but I don't know. If you could name a model which does this then I could research it for ya."
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hu7dmp | Can water from a dehumidifier be made drinkable? | Technology | explainlikeimfive | {
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"> Can water from a dehumidifier be made drinkable? Beyond mold/bacteria growth and other such undesirables, dehumidifiers leave trace amounts of heavy metals (mostly lead) behind in the water which isn't great for you. You'd pretty much need to boil the water and catch what evaporated in order to get drinkable water out of it - in which case you just took water from the air and made it liquid then evaporated and condensed it again. > Is this something that could be done at a bigger scale to help areas with limited access to fresh water? Not really practical - you need a LOT of energy to get meaningful amounts of water, and places without much access to hot water tend to be fairly dry to begin with - which means there's barely any water in the air to extract.",
"If you’re wanting to save water you could always use it in your toilet if you can’t get it purified enough to drink.",
"Technically every water can be made drinkable. Distill it (not sure if you would maybe need to clean out stuff that would evaporate before the water) and mineralize it. But its much easier to just clean normal water as the dehumifier works against the second thermodynamic law which makes the whole process inefficient.",
"I once did this with water from a AC. We boiled it for safety but yes, it is drinkable. It has very few particles that could be bad for you. About it being done on a large scale, I'd say it's not feasible atleast using a AC or dehumidifier. It's too expensive. Definitely easier to just purify other sources of water.",
"Sort of. Dehumidifiers aren't purpose-built for creating potable water, and so may contain components that may render the water undrinkable. Using the same principle as a dehumidifier, we can build an [Atmospheric Water Generator]( URL_0 ) that does produce potable water. They're pretty expensive at large scales, but there are a lot of groups working on the technology, both charities and commercial companies."
],
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|
hu85fk | How come iPhones take forever to turn on after dying, while Android phones can turn on the second you plug in the charger? | Hi guys, & #x200B; I have seen a few posts explain why it takes a few minutes for a phone to turn on after dying while you charge it, but no one has explained why it's such a big difference between iPhones and Android phones. An iPhone takes around 5 minutes (depending on the phone) before it can turn on again, while an Android phone takes around 20 seconds before you can turn it on after plugging in the charger. & #x200B; EDIT: One thing to note is that this is not the case for Apple's laptops, those turn on immediately. | Technology | explainlikeimfive | {
"a_id": [
"fylrmst",
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"text": [
"It's not specifically related to Android, since this is a low-level hardware function. Apple just decided (or whomever they chose to manufacture the charging chips) to require a certain level of charge prior to powering on and actually starting the OS. As to why different manufacturers made the choices they did, you would have to ask them. In general Apple *really* likes to control their customers, so this is likely another way they are attempting to \"improve the user experience\" by preventing people from powering on the phone before the OS has a chance to enable power management which could result in it immediately running out of power again.",
"Depends on the charger, many Android phones have been coming with fast chargers for years and Apple phones typically came with a 5W charger until recently. The problem is you don't want to drain the battery past 0% or else it'll damage the battery. It's likely a protection mechanism to make sure the battery has at least a certain state of charge before allowing itself to turn on. I've certainly see android devices that take a good 5-10 minutes before turning on to just the charging battery (without actually turning on.)"
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13,
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hu8pgs | Why do a lot of website login forms now only ask for email, and after successful submission, then they present you with the field to enter your password? | Technology | explainlikeimfive | {
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"text": [
"For some addresses, the next step might not be a password! A big provider might have both individual accounts (which need a password) and also corporate accounts which are 'federated' with a number of different identity providers. The form will take your email, look up the hostname in a big list, and then might ask for a password, or might demand a \"client side certificate\", or might first verify that your computer is \"compliant\" (normally this just means that it's running an approved OS), or a bunch of other things. (Source: I work at Microsoft, and some of our sites do this exact thing. But I don't work in any of the departments that provide these kinds of services, so I just know them from the end-user point of view).",
"Probably to prevent brute force attacks. They'll first verify the address is a registered account then offer up the password input.",
"Sometimes it's because certain emails have different authentication methods. For example, some use Google or Facebook login. Some redirect to another website. For example when you sign into GMail for Education some universities redirect you to their internal system to login that's not based on Google's."
],
"score": [
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5
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|
hudd2i | Why do device storages(and ram) always come in multiples of 4? 4,8,16,64,128,256 GB etc. | Technology | explainlikeimfive | {
"a_id": [
"fymdysz",
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"text": [
"The computer needs to send a number to describe which byte it wants to 'talk to'. Just like we use base ten numbers, computers use base two. With one digit, I can represent ten values. 0,1,2,3-8,9 Computers can only represent two. 0,1 By adding a second digit, I can represent 100 values. Computers can only do 4. Then 8. 16. 32. So, when you add another digit to the address that the computer uses to choose which byte to 'talk to', you're doubling the total number of addresses.",
"The answers here explaining how this is a feature of binary are valid but aren't necessarily the right answer. Historically when computers were much simpler they may not have had enough information(from the storage device) or processing power to account for odd amounts of RAM or storage. But these days it's mostly just due to tradition. There isn't any reason a modern PC couldn't have 14 GB of RAM or contain a hard drive that has any arbitrary amount of storage capacity.",
"It's because computers store data as binary numbers. Although they are multiples of 4, they're actually powers of 2 (since binary numbers are a a system where there can only be 1 of 2 values - 1 or 0)."
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