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6pi8q6 | Why do cars have AC buttons when you have the ability to change the temperature? | There shouldn't be a difference between a hot 69°F and an AC 69°F? | Technology | explainlikeimfive | {
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"The temp knob controls the mix of cold air and hot air. Hot air is generated by waste heat from the engine. With the A/C off, cold air is from the outside. So the coldest it can get is the ambient outside temp. With the A/C on, cold air is from the A/C system, which can be colder than the outside temp (in spring/summer, at least)."
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6pilof | Why do phone screens, with high pixel density and resolution, look far less impressive and crisp as a Monitor or TV with the same ~4k resolution? | Technology | explainlikeimfive | {
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"For the most part, I think phone screens are generally only at 2k resolution right now. There are rumors of 4k screens coming soon, but that is one large difference. Some of it may also depend on what kind of phone screen it is (AMOLED, LCD, IPS) as well as your brightness setting. Size is another factor. The pixel density is better on a phone, but if the screen size is too small, you won't notice the fine lines on a person's forehead as well just because they are smaller."
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6pipha | How do people find out about complex or hidden game easter eggs? Do players stumble on them naturally, or do they get leaked? | Technology | explainlikeimfive | {
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"Any and all of the above. Some Easter eggs are run into accidentally. Some are leaked by the devs for fun to capture the community for karma points. Others are found by users digging around in the binary code or other assets in the program."
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6pizen | Why did Adobe let Flash deteriorate, become hated, and die slowly? It was used everywhere and the primary player for online video, was there not enough value in that to be worth updating and maintaining it? | Technology | explainlikeimfive | {
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"A Flash applet is like a program. It can run it's own code and be used to write information to your computer. While modern up to date computers try and prevent this from happening, unknown bugs or design choices in either Flash, your internet browser, or operating system can lead to exploitation. It's just one more security gap you have to worry about, and it was designed in a time where internet security was much less of an issue From a usability perspective, it does not cleanly integrate with the rest of a website. You can right click \"inspect\" a webpage and see the various parts that make it work. Doing the same on a flash applet will basically tell you \"THERE IS FLASH HERE\" and tell you very little or nothing about what the app is doing. This is particularly bad for the visually impaired, as most screen readers are unable to read content from flash. The flash app does not work with back / forward buttons. Reloading a hung page will reload the app and usually erase any progress made. It is intensive to run on your CPU (not so much today, but computers are just that powerful). Older apps may not run properly on modern browsers. Each browser needs it's own plugin. It's one more thing you have to keep updated and install on a new computer. IOS no longer supports it. Older android phones can be blocked from installing on Google Play. Flash was a quick and dirty way to provide multimedia content when people were on 33.6 Kbps modems. Most apps would utilize vectors rather than store bandwidth intensive bitmaps. It was never meant to become a video streaming standard. Feel free to dive down the rabbit hole of Microsoft and W3C battles over web standards if you want to unravel the history there. (TLDR; without a standard, it was the only semi-universal way of doing it without licensing issues). It was neat gimmick that stepped up when there were no viable alternatives. Removal of IOS support was the writing on the wall, as it lost support for one of the top Smartphone manufacturers. It's limped along with Adobe (who bought it from Macromedia) threatening to kill it every few years. Like Internet Explorer 6, it looks like it may finally be laid to rest. SIKE! IE6 still trudges along with a 1% market share as of 2015! Flash's zombified corpse will probably still haunt at least a few of our grandchildren.",
"Flash was a huge step forward for adding rich web content... when it was new. This tool came around in 1996 when webpages were absolutely lifeless compared to now, the most you could do was scrolling text and a MIDI song. Flash gave you tons of bells and whistles. But the tools built into HTML and javascript got good and browser support for them got much better. What used to take fancy Flash now works with just built-in browser abilities, even games or video playback. Flash was getting squeezed out, and didn't really have a new area to grow into. However, even without Flash adobe is still heavily cemented as a go-to tool for creators... tons of content on the web, even if it's not flash, was probably made with Photoshop/Dreamweaver/After Effects. They're still making money as \"the digital creative stuff people\" and don't have to support Flash anymore. If anything, that's better for them. Adobe Animate CC is ultimately the replacement for Flash, offering similar functionality and animation tools while running on top of HTML5 instead of requiring users get the Flash Player plugin.",
"Steve Jobs signed its death warrant when he refused to allow it on the iPhone because it was inefficient and riddled with bugs and exploits that are still causing problems today. It was likely built that way so ot could perform on the lower power equipment common when it was built. Moving into speculation, Adobe were likely blindsided by Jobs' decision and didn't hsve enough time to redesign Flash for the modern mobile world.",
"This is going to be brief, but it's basically because Flash had the ability to run full programs on a system, and this opened a *lot* of holes in system security. Programmers could write whatever they wanted in a Flash program and the system wouldn't know to check it for viruses.",
"Simply because hackers started taking security flaws in Flash to their side, so that once a user views a site, he is already hacked, and Adobe pretty much has go much more important projects to work on, and as Adobe started letting Flash die, hackers took more opportunities and got into the flaws more, which pretty much killed it all for Flash.",
"The web is moving towards an infrastructure that doesn't require additional applications to be installed to operate media. In such a system, applications such as Flash and Silverlight will become deprecated. Flash is the first victim, mostly due to its inherent inefficiencies and security problems.",
"Adobe Flash has a lot of internal issues, causing it be used maliciously by people who know how to exploit flash player. Initially, they wanted to revive it, however, as technology moved on, and HTML became more and more of a useful programming language, people realized that they could use other tools to do the same things as adobe flash, but with less issues. Or at least issues that would end up being their own faults, and not adobes. Flash player is now used mainly for standalone objects and games, things that absolutely need to be separate from the site. Most browsers also have their own code compiler. Which is why youll notice that you only need flash player if you have outdated or older browsers."
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6pizgf | How do live visualization websites work? | I've seen many websites where data is updated real time and creates amazing visualizations that vary second by second e.g. Norse Live Cyberattack website ( URL_0 ) | Technology | explainlikeimfive | {
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"Here's one way to do it. You need 3 things: HTML, Javascript and a backend. The HTML describes how the parts of the webpage are organized. For your example, the large map is one part, the logo at the top is another part, the text at the bottom is yet another part. The backend is some computer running somewhere in the world that can accept http requests. In the same way you can visit ' URL_1 ', this backend may have a URL like ' URL_0 '. And while google give you information about a search bar, the 'attacks' endpoint will give you a list of attacks over the last minute (for example). This attacks endpoint would look pretty boring if you asked for it directly. Maybe something like: 'Budapest','Paraguay',25/07/17 10:32:44pm 'Hungary','France',25/07/17 10:32:57pm Essentially, this says \"At about 10:30 pm, someone from Budapest attacked someone from Paraguay and at about 10:30 pm, someone from Hungary issued an attack against someone from France\". Now the Javascript is the magic that makes it all work. The Javascript periodically asks for a recent list of attacks, then tells the Html what little lines and circles to draw. I'm glossing over a lot of details. For example: how does the *backend* know when the attacks took place? How does the javascript tell the html what to draw and where? If the javascript asks for attacks once per minute, is this *really* \"real time\"? If you have any specific questions I'd be happy to take a shot."
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6pjaaw | How does one create "incentive" for an artificial intelligence? What "motivates" them to fulfil their role? | Technology | explainlikeimfive | {
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"To start with, \"artificial intelligence\" is just another term for \"programs that solve complex problems\". We don't have artificial *general* intelligence yet (and it's debatable if we ever will) - that's the stuff that you see in science fiction that's self-aware and can solve problems it wasn't designed to do. Actual AI systems are just super complex computer programs designed to do a particular thing. Their \"motivation\" is that solving the problem is the only thing they're capable of doing. It doesn't make any more sense to ask about their motivation than it does to ask about what motivates a blender to make milkshakes.",
"It's a machine. It does what it's programmed to do. What motivates your car to drive forward, or your phone to ring? Same deal."
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6pkdx5 | How do game developers of hard games make sure their game isn't impossible to complete? | Technology | explainlikeimfive | {
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"They do a lot of beta testing. Simply put, they have people play the game and direct them to do different things in order to assess the difficulty. The goal is to make a game people will want to keep playing so TBH I think the testing is more to prevent a situation of the game being too hard, than the other way around. There is a balance between making the far end-game content being hard enough that the ones who achieve it can feel special, but making the game deep enough so that people enjoy pushing toward the end-game. Warcraft has played that balancing act with their developers for quite a while, for example the first two installments were considered too hard to clear the very end of the game, so when their 3rd major installment came out (Wrath of the Lich King), they actually dumbed it down a bit including making a first-release raid a lot more accessible to new players (Naxrammas). This balance of how difficult to make it is done by having players test it. Once its tested enough, the content is often released in a PTR or player test realm where people volunteer to play the newer content with the understanding that they are helping fine-tune it, so it might need balancing during the PTR."
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6pkfj1 | What are the rings of shadow that move across fluorescent tube lights? | Technology | explainlikeimfive | {
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"It means the tube is too old and needs to be replaced. Fluorescent tubes work by having filaments at the end shooting electrons into a gas. The gas absorbs the high energy electron and when it kicks it off it emits UV. The UV reacts with a phosphor that covers the inside of the bulb to give you white light When they get too old the gas doesn't excite uniformly anymore so you get bands of excited and bored gas giving you incomplete light"
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6pku2f | Whats so great about USB-C and why are people saying it is the "connector of the future"? | Technology | explainlikeimfive | {
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"Ya know how USB ports suck because you can never get them in right? USB C is the solution to the Heisenberg uncertainty port! There is no right way or wrong way, there is just the way That is by far its biggest upgrade over classic USB 3.0 & nbsp; Other than that it can provide *a lot* of power. USB PD specs it for 60W or 100W depending on the setup, that's enough to charge a laptop Its fast, it can support 10 Gbit/s, that's faster than SATA (3 the cable that connects to your hard drive) Its not fairly universal. Over the last couple years different organizations have been making specs on how to send their data over USB C cables. It is now supported by Display Port, MHL, Thunderbolt, and HDMI. So that gives it power, speed, diversity, and most importantly, no frustration Pretty nifty huh?",
"It's thinner than standard USB, symmetric, and supports multiple high speed protocols including USB, thunderbolt, and video. The MacBook Pros only have USB-C ports but still allow power, video, Thunderbolt, and USB3 using only USB-C ports. Phones are also replacing micro-USB with USB-C. Within a couple years, almost every new computer and smartphone will use primarily USB-C connectors.",
"Beyond what others have said: one of the problems with other connectors, like the Apple Lightning connector, is that the springy parts -- which wear out -- are in the (expensive) device. USB-C puts those parts in the (less expensive) cable.",
"Beyond all the technical reasons why it's a great standard, people are pumped about it because it's being taken up by many very large manufacturers as their 'one connector to rule them all'. One lucky guy I know doesn't have to carry different cables for his computer, phone, external battery pack etc- they're all USB-C. Jerk.",
"You know how you go to plug in a USB, and you're pretty sure it's the right way. Like 90% sure. And you try it. And it doesn't go in. So you flip it around figuring, well I've gotten that out of the way. Surely it's 100% the correct direction this time. And you try it. And it doesn't go in. So you flip it again because this USB connector violates the laws of physics, and sure enough it goes in. That's why we love the idea of USB-C. Also I'm pretty sure it's been presented that it will be capable of transferring video (like VGA or HDMI), reducing the number of varieties of cables required for setting up a computer. Less different cables = moar better.",
"To add to what others are saying: Usb-c is sturdy. Have you ever had a micro USB connector break? Where it'll only charge if you wiggle it just right? My wife closed a USB-C cable in the car door (don't ask) and it got bent a 45% angle... Still works fine. Granted, I replaced it as a precaution.",
"Not only is it reversible like others said, it supports almost every standard available. You can use it as a normal USB cable, HDMI, DisplayPort, VGA, power up to 100W, audio, and some ports also have Thunderbolt 3 functionality added in which gives it 40Gbit/s speed and PCIE so you could add external GPUs to devices, hard drives, and SSDs. It can do everything that required a separate cable into one cable.",
"USB Type C can do everything. The idea is that there is one small form factor universal for everything. This allows for a thinner device and how it drops the problem of running out of a certain port."
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6pl18m | How Do Wireless Chargers Give Power | I bought a wireless charger recently and i have no clue how it charges my phone | Technology | explainlikeimfive | {
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"Yer not alone in askin', and kind strangers have explained: 1. [[ELI5] How does Wireless Charging work? ]( URL_1 ) 1. [ELI5: How does wireless charging work? ]( URL_2 ) 1. [ELI5:How do wireless chargers work? ]( URL_3 ) 1. [ELI5 how does wireless charging work? ]( URL_5 ) 1. [ELI5: how the heck does wireless charging work? ]( URL_0 ) 1. [ELI5: How does \"wireless charging\" work? ]( URL_4 )"
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"https://www.reddit.com/r/explainlikeimfive/comments/4jbdpi/eli5_how_does_wireless_charging_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/1ijnal/eli5how_do_wireless_chargers_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/zfbp3/eli5_how_does_wireless_charging_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/2eeujg/eli5_how_does_wireless_charging_work/"
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6pleyv | What are containerized applications? | Technology | explainlikeimfive | {
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"I think it's easier to understand when you hear another name for containers: **jails**. Containers are basically a way to wall off one application from another inside the same computer. Application A cannot talk to application B without explicit permission. This has a number of advantages. First, it allows for much greater security. If application A gets hacked it's much harder for it to affect application B. Second, let's say that A needs version 3.0 of a shared library and B needs version 4.0. Normally it can be hard to have two or more versions of the same library on a computer but with containers it's very easy. Third, it's easy to package up all of the dependant pieces of software and libraries along with the main application. This makes it much easier to deploy the application across multiple computers without having to worry about the state of that computer. All of these are also benefits of virtualization. Containers have the advantage of requiring a lot less system resources than building a full virtual computer."
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6pltxq | How can I tell if I'm being throttled or being capped by my ISP. | Also, a better on explanation on the difference between the two. Recently I've noticed my ping has gone up by 20 MS and it's not just on one server it's multiple servers leading me to believe that it's my internet connection. I just want to make sure I'm being throttled before I contact my ISP about it. | Technology | explainlikeimfive | {
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"Depends on what you're using the bandwidth for. Your ping only rates the response time, not the amount of data transferred, and that's what they will usually use to throttle you. If you just sit in an empty chat room with nothing but text, not much data is even being transferred. But if you're downloading 1080p movies every night and sending massive attachments to business colleagues, the amount of data used is going to be much higher. Your ISP might throttle you based on how much total data you've used (even \"unlimited plans\" these days have caps, but they are generously large). Depending on what kind of data plan you've got with an ISP, the total bandwidth amount might be different. _________ Think of it kind of like a gas tank for a car, when you (or the person responsible for the service) pays the bill, they get X amount of megabytes (or other higher -bytes) per month. If you download or upload a total amount of data greater than that, it's like the car being out of gas. And a car without gas goes nowhere fast. If the ISP really wants to throttle you (but still consider your account in good standing), they'll slow you down to dial-up speeds. Kind of like you trying to drop the car into Neutral and push it yourself. That also means that, since your car ran out of gas, you didn't think ahead to refill it. You done messed up, by transferring so much data, the ISP might look at your history at just what you were doing to use so much (and if none of it was legal, they might just flag your account; like with file sharing legal disputes). This is like, since you're already pushing your car in neutral, a cop will sooner or later stop to see if you need help (maybe)."
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6plvcq | Why does airplane mode exist? | Technology | explainlikeimfive | {
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"Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do airlines ask you to turn off/airplane mode your phone during a flight when? Does it actually affect the flight? ]( URL_6 ) 1. [ELI5: Why does the Airplane Mode exist, if I am told not to use it of aircrafts? ]( URL_0 ) 1. [ELI5: With the presence of Airplane Mode, why do air stewards still insist that we turn off our mobile phones? ]( URL_1 ) 1. [ELI5: What is the purpose of \"airplane mode\" ]( URL_4 ) 1. [ELI5: Why do we have to turn our phones to airplane mode? ]( URL_2 ) 1. [ELI5: Why is \"airplane mode\" not good enough during takeoff and landing? ]( URL_5 ) 1. [ELI5:Why cant we use phones on airplanes? ]( URL_3 )"
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"https://www.reddit.com/r/explainlikeimfive/comments/1wvs5y/eli5_with_the_presence_of_airplane_mode_why_do/",
"https://www.reddit.com/r/explainlikeimfive/comments/30wded/eli5_why_do_we_have_to_turn_our_phones_to/",
"https://www.reddit.com/r/explainlikeimfive/comments/4g1fax/eli5why_cant_we_use_phones_on_airplanes/",
"https://www.reddit.com/r/explainlikeimfive/comments/23zoqd/eli5_what_is_the_purpose_of_airplane_mode/",
"https://www.reddit.com/r/explainlikeimfive/comments/1lhgo4/eli5_why_is_airplane_mode_not_good_enough_during/",
"https://www.reddit.com/r/explainlikeimfive/comments/5ea8qt/eli5_why_do_airlines_ask_you_to_turn_offairplane/"
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6plzsg | For shows with 'cold openings', how does Netflix know when to display the 'skip into' button after the scene? | This occurred to me while watching Gilmore girls, which begins with a difference cold opening scene for each episode. Was someone at Netflix paid to work or the timings episode by episode? Or is there a way to code for the beginning of the 'opening credits'/theme tune, ect? | Technology | explainlikeimfive | {
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"> Was someone at Netflix paid to work or the timings episode by episode? This is almost certainly the explanation. Either that or the production company that supplied the TV show to Netflix provided the timings."
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6poptg | If captchas look at your mouse movements to tell if you're a bot, how does it work on mobile devices? | Technology | explainlikeimfive | {
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"They actually don't always have to measure anything to do with your mouse movement or click. They can look for a cookie, or a collection of cookies that various Google services like Gmail place on your device, maybe even cookies from other companies. Also, your browser gives a lot of information to websites about its capabilities in the user agent string. URL_0 Obviously, the details of what exactly Google is looking for are secret or bots could just spoof them. Some people think that Google can actually identify individual people with their No CAPTCHA tech. They think Google can potentially read so much information from your browser that they can track you even if you delete cookies or take other common steps to avoid that kind of tracking: URL_1",
"It's not just mouse movements, it's also the precise location inside the box that you touch and the amount of time between when the page finishes loading and when you touch.",
"Whenever I have one in Mobile it gives me several different pictures or a single picture with a grid in it and asked me to choose the pictures or areas in the single picture with something like a car or street sign in it.",
"It's not just mouse movement, the captchas know you've used the same browser on other Google services (proving you're an active user, thus not a robot). If they're not sure, they'll ask you to do a regular captcha. Google will remember you completed the captcha, and probably won't ask you the next time.",
"You probably had to scroll the page, wait for the page to load, and your touch isn't as precise or constant as a bot supposedly would do.",
"All the top comments in here are correct. As well as JavaScript being able to access gyroscope data from your phone. Especially useful if you're holding your phone in your hands (which is highly likely) as the gyro data will change all the time which the captcha tool could also use. We'll never know the exact algorithm they use, cause if we did, then it wouldn't work! Hope this helps!",
"Also, what does the kaptcha say if you fail?",
"Don't they measure input and click rate on the individual fields before pressing the checkbox...",
"*puts on tinfoil hat* OP is a Google employee, and you're all being used to brainstorm new ways of fingerprinting. :)"
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6pq9e4 | How does a hard drive hold information even after being disconnected from a power source? | Technology | explainlikeimfive | {
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"Tiny sections of the disk are magnetized. By assigning 1 or 0 to a given polarity, binary data can be encoded onto the disk by magnetizing or not magnetizing given sections. Since this magnetization persists after it is performed it does not require an active power source. Basically, you're doing the equivalent of arranging a bunch of tiny bar magnets with the north pole pointed up or down. After they're pointed the way you want, you don't need any power to keep them that way."
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6pqh3z | In the sea of invisible data, how does a wifi receiver "know" which data is the requested, filtering it from the garble of other signals? | Technology | explainlikeimfive | {
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"text": [
"The information is encapsulated in an IP packet containing the MAC address of the machine \"requesting\" the data. The wifi access point has a MAC address table mapping which IP address is associated with that MAC address.",
"Specific frequencies, channels and addressing. Noise is a big issue with WiFi that we have to take into account when placing access points. You can download apps on your phone to scan for WiFi signal noise and make a map of where it is better or worse to see. We can separate our signals a bit by running on a different channel and frequency. Since 2.4GHz is the most popular with wireless devices in general, using the 5GHz band can be useful in high noise areas, but it has a harder time passing through walls. When the receiver does pick up a WiFi signal, it is going to look at whether or not it needs to do anything to it at all by its address. If the packet doesn't belong to the access point's network, it is just dropped and not bothered with."
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6pr54b | If video takes up so much memory how does the U.K. store all of their CCTV footage? | Technology | explainlikeimfive | {
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"dkriyss",
"dkrkxnb"
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"text": [
"You seem to underestimate how much space the gov't can get for storage. I work for a private company and our lone office server has 500TB worth on it, that doesn't include the network connection to corporate. We have a warehouse that is all server banks.",
"Couple of things to know about CCTV: The frame rate varies with what is going on - if there is no alarms or events it stores very little. Also a lot of cctv is limited and disposes of data after a set period \"first in, first out\" so not all of it is stored. So if you want footage from 5 years ago it may not exist, part of the reason why after an event it's important to get the footage straight away. As above data storage is very cheap. Source: look after cctv on trains, we actually had the police in yesterday picking up hard drives for evidence."
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6prg28 | How is the 'defrost' setting on a microwave different from all the other options? | Technology | explainlikeimfive | {
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"It sets your microwave to release short bursts of energy with long pauses in between, so that the heat has time to spread throughout the cold food without just cooking the outer surface.",
"It \"pulses\", so it's on for a few seconds, off for a few seconds. This allows the food to defrost evenly. Normal microwave use with constant power will result in chunks of the food being fully cooked or burnt, and some chunks still being frozen.",
"As others have said, it switches the microwave emitter on and off to lower the average power. How ever I interpreted your question as to how defrost is different than all the other power level options. It's a power level that the manufacturer thinks is good for defrosting foods. There may be lower power options available, but that is the one they think should be used. Or you maybe asking about a defrost program:. This will include things like telling you to turn the food over, asking you how heavy the food is (or weighing it for you) and maybe asking what type of food it is to calculate a good way to defrost the food."
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6psg16 | How do some software updates improve or worsen battery life if the battery is hardware? | Technology | explainlikeimfive | {
"a_id": [
"dkrtv0q",
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"text": [
"assuming you mean on smart phones. there are different ways, one of the major ways is changing the way apps run in the background. on the newest version of Android they limit how long your GPS can run when the screen is not on and the GPS uses a lot of battery. They have been doing this on iOS for awhile. iOS tends to not let nearly as many apps run in the background limiting the resources they use. There are other ways including push notifications but I honestly dont know how to ELI5 that one but I hope this helped.",
"By making the phone do less of things that tax the battery. A bug or a design flaw might make an up use the GPS too much or hold open an internet connection when it wasn't necessary. Being more efficient with these sorts of things can make a drastic difference in battery consumption."
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6pssy9 | How does the mouse know where to stop on a computer screen? | Technology | explainlikeimfive | {
"a_id": [
"dkrwqz1",
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"text": [
"The arrow on the screen is just an animation drawn by software on the computer. The mouse tells what motion your hand made, but it's up to the software to actually decide what to do about it. The computer knows how wide the screen is, so if you keep moving the mouse too far, the computer just stops the arrow right there.",
"Imagine yourself sitting by a table on the second floor of an apartment building. You're wearing a nice gray suit and a cap which says \"computer\" on it. On the table in front of you is a chess board, for reasons only known to art it is made out of LCD display glass. The board has a single Monopoly piece, preferably the dog, neatly placed at one of it's center squares. The room is pleasantly dim. I'm standing below on the street outside wearing a mickey mouse costume. Through an open window I yell to you: \"*Move the dog one square to the left*\". You comply and move the piece. I continue: \"*Move it again to the left*\". You move it as ordered. This goes on, square by square, until the dog reaches the last square on the board along it's leftern edge. But I'm not satisfied and still I yell at you to move the piece another square to the left. This time you've had enough, you're not going to make up pretend squares outside the chess board - not in this case. I yell 'Left' many times more but it is futile, in your mind my commands \"*Left, Left, Left*\" gets interpreted as \"*Stay, Stay, Stay*\". That is until I suddenly change my tune and say \"*Right*\" instead. Now you comply; the piece gets moved one square to the right. I keep yelling and you keep complying until the piece reaches the rightmost square. But beyond that you again won't move it no matter how much I yell at you to do so. Your principles are clear: any direction I suggest that would move the dog outside the designated board simply go ignored. And you are not one to stray from your principles. That's how it works, kinda."
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6ptebo | Why does opening an executable in Notepad and saving it again as an executable fail to work? | Opening an executable in Notepad only displays weird symbols, but why does saving the text using Notepad as another .exe causes the executable to be corrupted? | Technology | explainlikeimfive | {
"a_id": [
"dks1wva"
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"text": [
"Notepad is a program that is designed to display human readable ASCII charcters. As it reads a binary file or executable it will map the byte values of computer code and data into ASCII characters, or maybe Unicode characters that it understands according to < a whole bunch of things > . Any bytes that it can't represent as a readable character, it will interpret as a ? or a box character etc. And when you save it again, it will write the ? or box or glyph characters as their ASCII equivalents, not as their original byte code values, thereby breaking the executable."
],
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11
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6pux2g | why are ad videos shown without problem on my phone but when the video starts the internet becomes slow? | Technology | explainlikeimfive | {
"a_id": [
"dkse9zm"
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"text": [
"Because ads are cached, because they are smaller and loaded more frequently than videos. Moreover, they doesn't come from the targeted site but from an API that is [probably geographically closer to you than the site server]( URL_0 )."
],
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6pvt9i | How do web filters and anti-virus software perform a MITM attack without causing certificate warnings on a computer? | I know how certificates for HTTPS websites work. What I'm trying to find out is how various antivirus and filtering software works. At the heart, I know they intercept the traffic using the legit certificate then use their own certificate so you still see a HTTPS page that looks legit. But how do they do that without causing a certificate error to appear on the page? And could governments use this same feature to spy on HTTPS traffic? Edit: The bot that replied to my inbox linked me to a Google search (who would have thought to search there). That led me to this article that provides part of the answer: URL_0 | Technology | explainlikeimfive | {
"a_id": [
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"Because, as part of installing the antivirus software that does this, you install a root certificate on your computer that's accepted as just as trustworthy as any other certificate-issuing group. Yes, you can spy on HTTPS traffic by inserting yourself between the client and server if you could issue certificates that the client would trust and weren't using any other method to verify the certificate."
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6pvvpn | How hard is it to create a successful, new mobile operating system? | Technology | explainlikeimfive | {
"a_id": [
"dksj89f"
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"text": [
"Quick answer: **very** hard. Longer answer: Simply making a mobile operating system is difficult but not incredibly hard for a dedicated software company. What's difficult is building up the critical mass of hardware, owners and developers that are necessary for the ecosystem to thrive. Consumers want to buy a phone that has good hardware and a wide variety of apps available. Phone manufacturers want to pick an operating system that consumers want to purchase. Developers want to write apps for an operating system that has a lot of users. All three of these things have to be working well for the ecosystem to thrive. It's extremely hard to get them going when starting from scratch. Microsoft invested billions of dollars and wasn't able to succeed. It's especially hard to break into the market when the current market leaders are serving their customers well. If one of the two big players had a stumble then there might be an opportunity for a new company to step in."
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6pw4sg | Can anyone explain awful dubbing on TV ads? | I've noticed that here in the UK some adverts have English actors doing the voice work, but the dubbing is terrible! | Technology | explainlikeimfive | {
"a_id": [
"dksmf2h"
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"text": [
"It's cheaper to poorly dub a foreign ad than to remake it from scratch. If you're talking about ads where it's clear they're speaking English but it's still dubbed, that's because they try have more local accents. It's easier to sell a product to a Brit if it's a Brit telling them to buy it and not an American. Usually it's just cheaper and easier to do one quick recording than try match it up properly."
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6pxjlo | why is cybercrime so hard to stop? | Recently my family has been a victim of cybercrime in the case of stolen identity. We have literally tried everything from contacting the server who claim not to host the website to shutting down each bank they use just for them to open another one. It seems like no one can do anything about it. Why is it so hard? | Technology | explainlikeimfive | {
"a_id": [
"dksyttf"
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"text": [
"Because nobody really cares about cybersecurity except for nerds like me who see the face of normal people glaze over whenever we start evangelizing. Because we're all pretty much using a bunch of technology in ways nobody ever intended, for a bunch of *ridiculously* sensitive information. Because banks and other financial institutions don't care about really verifying the identity of account holders, and so approve accounts so long as a name and SSN and a few other factors match, and don't bother with some more secure means of proving that you are who you say you are. Because it's a global problem and we don't have a world-police. Because people are the weak link in security now, and despite a ton of really good security options, they value the convenience of free wi-fi over making sure their bank account info is secure. Seriously, there are several conventions each year where infosec pros get together and bitch about how nobody else bothers to secure their shit, and talk about new ways people have found out how to exploit some bad piece of code But really it doesn't matter because people are dumb trusting monkeys by nature and if I really want someone's identity, all I have to do is ask them the right questions the right way and they'll give it to me without a second thought until it's too late (important note: I don't *do* things like identity theft, but I work IT and I have had to stop people in the middle of giving me their social security number, credit card number, online banking password, and a bunch of other sensitive information, when all I'm trying to do is fix their youtubes.)"
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6pyvit | Why do pens not work on certain surfaces, but after scribbling on another surface and getting the pen to write, it works on the original surface? | Example: I had a single sheet of paper on top of metal and my pen wouldn't work. I scribbled on my notebook until my pen started working. I turn to write on the original sheet on top of the metal and this time, it worked | Technology | explainlikeimfive | {
"a_id": [
"dkt8qay"
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"text": [
"The ball at the tip of most pens is self lubricating with the ink. If left uncapped long enough, the ink will dry out and the ball is effectively glued in place. If the ball can't rotate, fresh new ink can't get by. On a thin paper on a hard surface, or a smooth surface aka \"flat\"... only a small part of the surface is making contact with the ball. To get a stuck ball moving again we need more friction. A few sheets in your notebook has enough spring in them to deform around, and touch the sides of the ball, imparting more friction... thereby breaking the stuck ink, fresh ink comes out, lubricates the ball and everything writes off into the sunset."
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21
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6pyvjv | What is the purpose of spam email that entices a reply with no personal information? For example, I have a spam email that just says, "if you don't want to talk to me, just say it." In what way are spam senders benefitting? | Technology | explainlikeimfive | {
"a_id": [
"dkt9mzu",
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"text": [
"By replying, you're giving the spammers three pieces of valuable information. First, you're verifying that the email address they sent is a valid email address that is being checked. That has value to other spammers, making your email something they can sell. Second, you're verifying that their email message wasn't screened out by whatever anti-spam filters are in place. That shows the skill of the spammer's ability, making their services appear more valuable. Finally, by replying you're verifying that you have the psychology that reads these junk emails, and will from time-to-time, respond to unsolicited messages, which makes you an appealing target for future efforts.",
"Sometimes it's psychology. As an IT guy, I've gotten way more personal information and passwords told to me over the phone by saying \"I'll never ask you for personal information or passwords\", which I guess means that I'm one of the good guys since nobody who was a bad guy could ever say that... So similarly, maybe no legit scammer would give you an out?",
"Generally with spam, they send out similar emails to huge numbers of emails. often not even specific ones, just any combination of letters and numbers and common words, etc. the program generates. If you reply it confirms that there's actually a person connected to that email address. Once you confirm that, someone will either try toscam you for real, or sell your address to someone who will."
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6q203o | How does a hacker leave a "trace" while hacking? | Technology | explainlikeimfive | {
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"text": [
"Can be multiple things depending on what the \"hack\" was. Most often you're looking at things like an IP address that was logged somewhere when they tried to access something, or logs of account activity or commands run by the system. A lot of Infrastructure is heavily monitored and logs or alerts are sent via email or text to admins of the system. In the case I know here, it's a \"Honey Pot\" server that tracks any and all activity coming into it. Since it isn't used for anything other than being a fake server that looks like a weak point in the network, any hits on it will be an attempt to get in. It is checked about once a week for new activity, but most of the time just knowing the IP is useless because no one above the age of 13 would try to break in without using a Proxy or VPN of some kind. Though depending on who they use and the nature of the activity, law enforcement can work with the VPN provider to find the original person, if they're being really sloppy.",
"Mostly log entries of the form \"Someone logged into the administrator account 'hasaweakpassword' at 22:17:09, coming from the IP address 192.168.0.2\", or various software lying around which they copied to the machine to help their hacking efforts. The logs can tell you where the hackers came from, and the software can tell you how they operate, and maybe even who they are - it often contains output text or information about variable names which tells you the language the attackers most likely speak. Of course, a hacker who has full control of a system can remove these traces, but they may not have the time to do that when the victim notices the attack and shuts down the systems, or they may not do it completely when there are a lot of machines involved (which is quite common).",
"I once did forensics on a site that had been hacked. It was running BSD Unix, and kept a log of every network connection (they pretty much all do that) and also kept a log of every command typed by an administrator account. The attacker was clearly what we call a \"script kiddy\". That's someone who doesn't really know what they're doing, but is following scripts and using tools written by much more experienced attackers. This particular script kiddy got in by using a well-known flaw in the wuftpd FTP server. The first thing I did was fix the server to close that particular point of entry. Reading the command logs was educational. Even though it was a Unix system, this particular moron started executing DOS commands once he got in. You could see from the logs that he was becoming more and more frustrated and confused because nothing worked. The attacker also then downloaded more malware and hacking tools to the server once he got in (this is common, once an attacker gets into a system, they like to make changes to it to make sure they can always get in again later). The network logs told me where he downloaded the tools from. I was able to then head over there and look around to see what tools and information could be found at that site. I finished up my work by modifying the ftp server to *look* like it still had the same security flaw, but would actually dump the attacker into a sandbox and immediately send me an email if someone tried again. As other posters have pointed out, most computers keep logs of everything. A very good attacker will edit the logs to remove every trace that they were there. Assuming they can find them all, that is. A sloppy attacker will miss many or even all of them. There are other things you can look for too, such as files whose sizes or \"last modification\" dates aren't what they should be. The \"last access\" date can also tell you what files the attacker may have accessed. There are other ways to detect that files were tampered with. For an excellent book about the subject, I recommend Tsutomo Shimomura's book \"Takedown\", which is the story of how Kevin Mitnik broke into Tsutomo's computers, and how Tsutomo tracked Mitnik down and helped the FBI capture him.",
"Heres a snippet from a real life log like /u/StoicJ and /u/brazzy42 are talking about. It shows what FTP requests were made, with what account, to what website, over which IP for a website I manage. If some sly user was messing about with the files on the website, it is through this log that their changes and requests could be tracked. Jul 19 14:48:49 ftp pure-ftpd: (admin@wiki. URL_1 [email protected]) [INFO] Timeout - try typing a little faster next time Jul 19 14:21:58 ftp pure-ftpd: (admin@wiki. URL_1 [email protected]) [INFO] Logout. Jul 19 14:20:58 ftp pure-ftpd: (admin@wiki. URL_1 [email protected]) [NOTICE] /var/sites/w/ URL_0 uploaded (6233 bytes, 413.76KB/sec) Jul 19 14:20:01 ftp pure-ftpd: (admin@wiki. URL_1 [email protected]) [INFO] Logout. Jul 19 14:19:01 ftp pure-ftpd: (admin@wiki. URL_1 [email protected]) [NOTICE] /var/sites/w/ URL_0 downloaded (6348 bytes, 10454.93KB/sec)"
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6q4esq | What is actually happening when we turn up the volume on a stereo, TV, or computer? | This may sound pretty simple, but I got into some jazz cabbage last night, and could not fully wrap my head around an explanation as to what is happening to make the volume louder. Please ELI5! | Technology | explainlikeimfive | {
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"text": [
"The basic answer is that more power is being provided to the amplifier circuit. An amplifier with no volume control would be at top volume all the time. The volume control limits the amount of power that is sent to the amplifier. It does this by sticking a variable resistor in the flow of electricity. If the resistance value is high then not much power gets through and the volume is quiet. If the resistance value is low then more power gets through and the volume is loud.",
"Think of it the opposite way. A dimed volume knob is allowing the entire signal to pass through whatever amplification device. By turning it down you bleed some of that signal to ground before it is amplified, resulting in less volume. It's why fancy stereos list volume as -X. The lower the volume, the greater the amount being bled to ground. So whatever means of amplification is making the signal louder (there are a bunch of ways to go about this), but as you turn down the volume, you send less signal through, resulting in less signal being amplified, for less volume."
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6q4t8k | Why can you only tune FM radios to odd numbers? | Technology | explainlikeimfive | {
"a_id": [
"dkuisg4"
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"text": [
"In America, FM radio stations are given 200 kilohertz of spectrum on which to broadcast. So, the frequencies were always going to end in either an odd or even number. It was completely arbitrary that they decided to end them on odd numbers instead of even."
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6q5ujq | .rar .zip .7z etc why are there so many ways to compress files? Is there a meaningful difference between them from the end users perspective? | Technology | explainlikeimfive | {
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"Most it is due to the history of data compression on the PC. The first data compression programs appeared in the late 1980s, and through the 1990s there a number of competing standards, zip, rar, lha, and arj among them. Zip emerged the winner and became the de facto standard for a while. About that same time, the inventor of the zip format, Phil Katz started to have mental health and substance abuse issues, and the program was no longer being improved. PC's transitioned from command line DOS to GUI Windows, and rar beat zip at making the jump by making WinRAR, the first widely used compression program for Windows. This allowed RAR to get back into the race, and both WinZip and WinRAR remained popular. However, the rar algorithm was patented, while Katz had opened the zip format to everyone. As file compression started to become embedded into other programs, zip regained the crown once again. Things didn't change much until 2008, when Igor Pavlov released 7zip. It was a lightweight, but powerful program that handled all common compression formats, and offered a new format, 7z, with improved compression ration. > Is there a meaningful difference between them from the end users perspective? Not really. WinZip and 7zip are free, WinRAR is commercial, but you can get fully functional \"trial\" version for free...no one ever pays for it except corporations. The zip format is more widely used, rar might be what you have at work, and most people think 7zip is currently the superior program.",
"They're all very similar but make tradeoffs. They're all lossless compression generally based off the algorithms of Lempel and Ziv Zip is basic, it just uses DEFLATE and gives you decent compression and moderate usage of resources. Rar is also pretty basic, but it's algorithm is proprietary, this is why WinRAR always tries to make you pay. Another fairly middling algorithm 7z gives you lots of options. By default 7z will use LZMA2 which gives you good compression but takes a fair amount of resources to do, but also few to undo. Other options are DEFLATE just like .zip uses, you'll get the same results. You can use LZMA, the predecessor to LZMA2, fewer resources used but a bigger slider. You can also tweak a bunch of dials and knobs with 7z, it can give you really really good compression as long as you're willing to wait a few minutes for it to finish, it can also give you light compression if you just need a bundle now Rar should never be used. Zip will live on as long as WINZIP ships with Windows, but 7zip is really where it's at these days, you're generally not resource limited on a modern computer so even pretty good compression is faster than poor compression used to be",
"Short answer but different compression schemes usually trade-off between degree of compression and speed of compression and decompression. There are also two main classes of compression algorithms: lossy and loss-less. Loss-less means the data is 100% identical after compression/decompression... lossy means some information is lost in the process but this is usually engineered to be less- or unimportant data (for example, frequencies of sound that few people can hear in audio recordings). For most use-cases as a casual computer user it doesn't really matter if you are compressing a file to email to someone or something like that, but for Youtube or Netflix, for example, yeah it matters a great deal, like millions of dollars worth of mattering because it can reduce the required server space and bandwidth utilization.",
"Anyone can write a program to compress files. Sometimes, other people start using it, and it gets popular. This often happens because a compression program will do things differently / better from other existing compression programs. For example: - Allows adding multiple files to a compressed file - Allows splitting a big compressed file into multiple files to fit on multiple disks / downloads - Uses a different / better / faster compression algorithm - Runs on / better support for a different OS from other compression algorithms - Uses an algorithm patented by our company so no other company can sell it - Uses a non-patented algorithm so we can give it away for free - Designed to be a drop-in replacement for an existing compression program - Takes advantage of multiple processor cores to compress faster - Special support is provided by popular OS's or programs Some people will adopt a new compression program that does a better job of providing the features they care most about.",
"Yes! There is a significant difference between difference algorithms and how they work, and what they are good for. If you have a text that is very long but very repetitive, you can use __dictionary__ compression. Each word you see you put into a list, and replace the word with the position in the list. When you want to decompress, you read each number and find out which word it was. You can also do this for letters using something called __huffman coding__, Another way of doing the same thing is to instead tell the reader to look somewhere else. Most songbooks do this: instead of repeating the refrain they simple tell you to go back to where it was printed first! You can also make it like a rebus: start with the first word, and then for each following word tell the reader what needs to change the next word. This is called __delta coding__. This is not practical for actual text, but very good for images where you can say how much more/less red the next pixel is. A compression algorithm combines these different ideas to create a very specialized tool. The most specialized ones are only used for one thing: PNG for images, MP3 for music. They can theoretically be used for other things, but it would not be useful. Others are useful in more situations, but not as efficient as the specialized ones. They also require more or less time because of this. If you have to check each word in a list it is really slow, but your refrain is instant! Solving the rebus is slow for words, but quick for pixels in an image: more red, less blue. As an example, try to use the \"refrain-compression\" on an image: it would work on a chessboard but not on a sunset, because each \"refrain\" is different!",
"One thing I haven't seen mentioned here: rar originally broke the compressed file into multiple equally sized files. This was important when you had to move the files via floppy disc. Or when you were downloading the files via dial up. Obviously that's no longer necessary (or it's automatically handled by the transfer mechanism aka: bittorrent). But it was important at the time.",
"In the PC / DOS world, before the public internet, in the BBS days, boards generally offered zip files. The arj format became popular in the warez scene, and many an evening was spent downloading 1.44MB arj files at 14.4K then 28K. The advantage of arj over zip was that it could create a multi volume archive - that is if you had to compress say 3mb, it could be split into disk1.arj and disk2.arj, both fitting on the floppies available at the time. When 56k and the public internet came out, usenet and newsgroups became popular, and rar became the standard of choice. Both modems and usenet could be flakey, and the files you downloaded might have contained errors or be missing parts. With rar, you could not only do a multi-volume split, but also create parity files. The posts on usenet might have contained disk1.rar, disk2.rar and disk3.rar, but also disk1.par and disk2.par. The parity files were much smaller than the rar files, but allowed magic to happen. If you'd download disk1-3.rar and there was some problem with disk2.rar, the un-rar tool could use a parity file to rebuild the missing content and repair your download. As DSL and cable internet came about, connections became more reliable so the use of multi-part archives dwindled. But if you go to usenet to this day you will see massive archives broken up into CD or DVD size, and parity files included with the post. So yes, as others said, there were improvements in the compression algorithms along the way, but I believe the biggest reason arj then rar were adopted were their multi archive ability and parity. In UNIX land, before zip, there was tar, which was designed to create a file that could be indexed when stored on tape. It didn't compress, just archive. Zip was later commonly used to compress tar files, so you'd see .tar.gz being a common format. Tar is still popular in the Linux / UNIX world, it does have some advantages, especially as tape is still being used as slow access storage for massive, huge data collections.",
"It's barely been mentioned that there are far more compression formats than the three you mentioned: (to add) .zip, and its cousins, compress files individually, so you can browse through them and pick out any file you want really quickly. Something like .tar.gz compresses all your files wholesale - like joining all your documents together into one file (tar) and *then* compressing them (gz). This means a better compression ratio, but only for archives not expecting to be cherry picked from. Some are *okay* at compressing (say, reduces size of text by ~50%), but have the trade off of being *insanely* fast (e.g. lzop, lz4). This can be used under-the-hood to compress whole file-systems or transfers with negligible waiting. They also have the benefit of being inherently tiny programs for embedded/bare-bones systems. The other end of the spectrum is something like .xz. It takes a lot of CPU processing power, but squeezes the file as much as possible (in select cases). If you were a website sharing a file you only had to wait 1 hour to compress, but would save each of your 1000 users 10 minutes of download time, it's worth it. The different algorithms lend themselves to different situations and data stored within them. There are nuances, but as an end user, most formats which benefit the most from compression *already are* compressed. jpg, png, docx, mp3, all have baked-in compression."
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6q6gay | How is it possible to get Doom to run on so many devices that are not even purpose built as home computers, like the GPS console on someone's car for instance? | Technology | explainlikeimfive | {
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"Doom is an old game. It was designed to run on the very limited hardware of the time. Even a very limited computer by today's standards can be powerful enough to run Doom. Source code for Doom was made public in 1999, which made it possible for people to port the game to other platforms. People try to port it to unusual things like GPS consoles and printers mostly for fun - [there's even a webpage for it]( URL_0 )."
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6q7727 | how encryption works | Technology | explainlikeimfive | {
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"text": [
"Yer not alone in askin', and kind strangers have explained: 1. [ELI5:How does encryption and decryption work ]( URL_3 ) 1. [ELI5 Can Someone please explain how encryption works ]( URL_1 ) 1. [ELI5: How does encryption work? ]( URL_5 ) 1. [ELI5: How does public-private key encryption work? ]( URL_6 ) 1. [Eli5: Encryption ]( URL_0 ) 1. [ELI5: How end-to-end encryption works? ]( URL_4 ) 1. [ELI5: How does encryption work? ]( URL_2 )"
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"https://www.reddit.com/r/explainlikeimfive/comments/tpqjo/eli5_can_someone_please_explain_how_encryption/",
"https://www.reddit.com/r/explainlikeimfive/comments/32i5jr/eli5_how_does_encryption_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/27v8ja/eli5how_does_encryption_and_decryption_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/3x5o2u/eli5_how_endtoend_encryption_works/",
"https://www.reddit.com/r/explainlikeimfive/comments/5ulifx/eli5_how_does_encryption_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/1jvduu/eli5_how_does_publicprivate_key_encryption_work/"
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6q779g | How far away are we from achieving a breakthrough in data compression like Pied Piper's compression algorithm from Silicon Valley? | I am aware that SV is not totally true but man do they make it sound real! I think data compression is incredible and I would like to hear about complex concepts currently being used and how they can be improved upon. | Technology | explainlikeimfive | {
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"We already have data compression that often comes within 10% of the theoretical limit -- the place where mathematically there is nothing left to compress out.",
"We already have really really good compression, you're just underwhelmed because you use it so often it isn't special, but we have it. H.264 can stream 4k 60Hz video with a bit rate of just 240 Mbits/second, this seems high until you run the math on what uncompressed video would be. 4k video is 4096x2160 pixels, with 3 colors per pixel and 8 bits per color, multiply that by 60 frames per second and you have 12.74 Gigabits/second That's a 53:1 compression ratio! And you could even tweak the settings for your specific video to get better than that without noticing the compression There is a limit to how much you can compress data before you begin corrupting the information too much, many of our compression schemes are lossy so you just crank the dial til it goes to shit and turn it back some, but there are others that are lossless. For lossless compression you can actually check the information content(entropy) of the data in advance to know the maximum possible compression of the file, we're usually pretty close to it"
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6q79yd | Why is it that upgrading a phone or a computer to a newer operating system typically results in the device performing worse or slower? | Technology | explainlikeimfive | {
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"text": [
"Because phone companies use planned-obsolescence to slow down older devices artificially in order to push newer devices. OR Because newer software is more taxing on the hardware than older versions was. Both of these have some truth in them, I recall several instances where it was claimed that around the release of newer generation hardware, many smartphone manufacturers utilise the first method, while the second option is almost a passive process as apps become larger and more complicated. Edit: I should note that the intentional sabotaging of older generation devices is often referred to as a conspiracy theory, with little corroborating evidence. It is likely that poor optimisation and growing complexity of apps and growing reliance on constant connectivity is the main driving force behind the increased strain on your hardware.",
"Newer operating systems take advantage of the hardware specs of the newest devices... what's the point of having the newest hardware if the software can't take full advantage of it? The flip-side is that more memory-intensive or processor-dependent features may run more slowly on older devices running the newer OS."
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6qabuh | How do we track launched missiles yet lose passenger planes? | Technology | explainlikeimfive | {
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"When a missile is launched there is lots of attention on it but with thousands of planes in the air at any given time you can't have multiple satellite pointed at all of them all the time. If you had a dedicated satellite array that focuses on one plane you wouldn't lose it either.",
"I assume you mean intercontinental ballistic missiles. They go into space which means that you can spot them on radars very far away. But even then the radar coverage is not complete and only on exposed areas. So if Australia or South Africa were to launch a missile at the US it would likely go unnoticed until right before it hit. However that is a calculated risk. Passenger planes usually fly much lower then intercontinental missiles so the range of the radars is much smaller as the airplanes further away will be bellow the curvature of the Earth. Even then we are pretty good at tracking aircrafts. Lots of aircrafts fly every day which we are able to track and even those that suddenly disappear is found within a few days. There are very few aircrafts we do not know the whereabouts and in all cases it is very likely that the pilot did not want the aircraft to be found. It is possible that some militaries have been able to track some of these aircrafts but is not willing to disclose these capabilities."
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6qbr6b | How networking at home works. | I'm puzzled by alot of terms used, and have quite a few questions. So in case future people want to view this as a guide, can some kind soul please just explain everything? Like what does what, what connects to what, what not to do, setting up certain stuff, etc. | Technology | explainlikeimfive | {
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"text": [
"I'm assuming you mean IT networking. Some basic terms: Modem: Turns the signal from your Internet connection into an Ethernet signal so your router can understand it. Router: Connects networks together, usually connects a private home or business network to the internet. Switch: Connects devices within a network together using ethernet cabling. Wireless access point: Same as a switch, but for wireless devices. Server: Provides some kind of service to network devices, such as storing files and performing management functions for administrators. Firewall: Protects private, internal networks from malicious activity on the Internet. So you have devices and the internet, but something needs to connect the two, since you can't just plug your phone or computer straight into the fiber or cable line coming in to your house. Connecting the devices to the internet is the router's job. Devices tell the router when they want to go to the internet, and the router \"routes\" their traffic through many different protocols and behind-the-scenes processes. One of them is IP, internet protocol. An IP address uniquely identifies devices so they can communicate with other devices, which also have their own IP addresses. IP addresses are divided into ranges so that you can have different, separate networks for everyone's home, business, location, etc. All this means is that devices on your network can communicate with each other, but require a router to communicate with other networks, one of which is the internet, which is literally the \"inter-network\" connecting private networks together. At a business that needs to support hundreds of devices like printers, computers, and phones on their network, they will have standalone network devices for each network function, so they will have their own separate router, server, switch, etc. At home where you have probably no more than 10 devices, you will have an \"all-in-one\" device that acts as your modem, router, Wireless AP, server, switch, and firewall, which is very convenient. Most of it will work out of the box. To access your home router settings, go on a computer on your network and open Command Prompt, then type ipconfig and press enter. Find the one that says Default Gateway. Type that IP address into a web browser and login. The login will probably be on a sticker on the device, if not then you have to search for the model # default login."
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6qc35z | Why do intercoms on trains, airports, in stores, etc. usually have such bad sound quality and are hard to make out? Surely there would be better, more easily understandable alternatives? | Technology | explainlikeimfive | {
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"Well, simply, it's cheap, and upgrading the speaker doesn't really increase the company's profits, so, they don't bother. A more naïve and less \"companies-only-want-money\" way to answer this, is that in a large room, if many speakers at different parts of the room are broadcasting audio at the same time, since you're not equidistant from all of the sources, echos and reverb causes the audio to sound less clear, more muffled, and thus hard to understand.",
"Pro sound engineer here: Usually it is human error. Systems like these are installed by professionals that cannot get client approval unless they can demonstrate that it sounds excellent. The problem is that the people who typically use these systems aren't audio professionals and often don't get proper training. For example those hand held microphones with the buttons on the side and the curly cables are not mention to be held directly against your mouth. This causes them to be over driven cause distortion that you hear coming out of the speakers. Also often times the volume settings on these systems get adjusted improperly by employees who again don't really know what they are doing. Due to the nature of these systems, there are several different places in the audio chain where the volume can be adjusted and if it's too low in one area and too high in another, you get distortion. Lastly employees who regularly use these systems to say the same or similar messages over and over have a tendency to mumble and speak too quickly. That's unfortunately human nature for an action you repeat over and over again."
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6qe9e3 | Blue light is suddenly an issue, hurting our sleep, but generations before us watched TV before bedtime, bathed in so much blue light. What's the difference? | Technology | explainlikeimfive | {
"a_id": [
"dkwl95d"
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"text": [
"The issue is we have much brighter technology and have actually studied the effects. Previous generations also had black and white televisions or much smaller screens to look at, plus no cell phones so the amount of blue light they viewed was greatly reduced."
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6qetyr | Why is is so hard for goverments/groups to shut down The Pirate Bay completely while they managed to shutdown KickAssTorrents in 1 hit completely? | Technology | explainlikeimfive | {
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"text": [
"Many people kept mirroring the content of pirates Bay site to keep it alive, not so much with kickasstorrents. On a global scale, pirates Bay is more known and popular than other torrent sites",
"Because they got to the owner and there were apparently no emergency plans in place to dump everything to somebody in an extradition safe country. On the other hand TPB guys just don't give a fuck",
"Because the owner of the KickAssTorrents web domain lived in a country that decided to cooperate with the U.S. Feds and extradite him.",
"Pretty much because KAT or ExtraTorrent admins were pussies and co-operated with authorities to avoid trouble. TPB are straight up mobsters and don't give a fuck.",
"I understand that the people keeping Pirate Bay alive don't care but, what is keeping the site alive? Are they moving the ''server'' location every month? I mean, for my pov over now the years, it's not so hard for some anti piracy groups or governments to shut down piracy stuff, so i just don't understand how PB does it when governments now seems to take a easy way to solve the PB issue by just forcing ISP to block the site in their countries while other piracy sites gets shutdown so fast, So sorry for the messed up question, i just don't understand how it can be so hard for all the anti piracy places to shut them down completely when they can do all these others sites so quick? (Also, i just wanna say, i'm not from some anti piracy place or anything, i'm curious to why they have issue shutting them down while i read all the time online about a piracy website getting shutdown and then i still see PB online somehow, so please don't take it as i want the site to be shut down, just curious to why it hasn't been that already :-) ) Sorry again for wall of text :-P And thank you all for your replies! This is an interesting subject!",
"There's also Denial Of Service (DOS) rights. By blocking access to websites, you are essentially denying people the right to access content or information etc. Movies and music are not illegal to own, and making a copy of them yourself does not deprive the owner of his, so its not theft either. Copyright laws are difficult to enforce, and rightly so."
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6qezsd | How do sewing machines work? | There is a thread through the needle and the thread in the bobbin, but how do they create any hold? How does the needle pick up the thread from the bobbin and not just puncture the material with no outcome? | Technology | explainlikeimfive | {
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"text": [
"They work by the thread going into the cloth and then going back up and on the other side of the cloth there is another thread that is interlaced with the top thread. Here is a gif. URL_0"
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6qf056 | How galaxies can be hundreds of light years away, and yet we can still photograph them from earth? | Technology | explainlikeimfive | {
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"text": [
"First, it is important to level set on the distance. The closest galaxy to the Milky Way is the Andromeda galaxy. It is around 2.5 million light years away. A light year is the distance that light travels in a year. Since light travels at roughly 300,000,000 meters per second, a light year is a very far distance. Now to answer how galaxies such distances away can be viewed and photographed. Time. The universe has been around for billions of years and has been expanding during that time. This means that billions of years ago when the light was emitted from very distant galaxies and started making its way to Earth, it didn't have as far to travel. This is how we can see things that are farther away in light years than the age of the universe.",
"What you capture in the photograph is that many light years old. The star may not even be there anymore. It's easier to get with sound: think of a thunder. You first see the lightning and hear the sound a few seconds later. The sound happened at the same time, and when you're hearing it, the lightning is no longer there.",
"Hundreds? [Try *billions* of light years]( URL_0 ). There is nothing in space to stop light so it travels forever and the universe is really, really, unbelievably old.",
"Because when you look up at the galaxies, you're seeing them as they looked like millions or billions of years in the past. We don't know what those galaxies currently look like. For all we know, that galaxy could have collided with another galaxy and looks completely different from the images we are gathering of it."
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6qfe5m | How do cooling mattresses/mattress pads work? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"They contain pieces of a gel material which has a very high heat capacity. That means if they've been sitting around at room temperature for a while, they have significant ability to absorb heat from you (your body is warmer) before they reach your temperature."
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6qftoy | Why private companies like Facebook need their own satellites in orbit. | Technology | explainlikeimfive | {
"a_id": [
"dkwydmx"
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"text": [
"Most of the communications satellites in orbit are privately operated. If your company needs satellite links and doesn't own a satellite you have to pay a company that does own a satellite to use their equipment. If you use a lot of satellite bandwidth, or you need specialty links (or god forbid, a commsat outside of the normal commercial orbits) that can get *very* expensive. At a certain point it is a better investment just to launch your own satellite."
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6qfzw7 | How do emails detect "spam" and send it straight to the "junk folder" but allow some emails come through to your main inbox? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"There are numerous ways to identify spam (bulk, unsolicited email). A lot of spam is identified before it is even accepted by the mail server. A mail server always knows the IP address of the server that's trying to send email to you. The first line of defense (and the oldest) is to refuse to accept email from places that have a bad reputation. Your ISP or email service provider (ESP) can maintain their own lists and/or can subscribe to third-party lists of \"bad\" IPs and simply refuse to accept email from them. Besides outright refusing to accept email, your ESP can go ahead and accept the email and then use a wide variety of tools to determine whether or not to classify it as spam. Many systems use sophisticated scoring systems to \"grade\" the email. Does it come from a known good or bad IP? Does it contain spammy language? Does it include a link to a known spammer website? Does the website get DNS from a known spammer? Does the email contain a known spammer email address? Have other recipients classified similar emails as spam? Is the sender's email address in the recipient's address book? And so on and so forth."
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6qgvtn | How come storage devices like USB drives and memory cards etc don't need batteries? | Like SD/MMC cards for example don't have batteries.. I don't understand! | Technology | explainlikeimfive | {
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"text": [
"Interesting question! USB drives and SD cards are examples of flash memory, which is based on something named \"floating-gate transistor technology\". A flash memory is made of several cells, each of which is similar to (one or more) transistor. Transistors are tiny electronic devices (technically, semiconductor devices) at the core of all electronics built in the last 50 years. A particular kind of transistor, the MOSFET, has 4 terminals: source, drain, gate, body. The important thing is that the gate has a layer separated from the body by an insulator. Floating-gate transistors are like MOSFET but with two gates: the control gate on top, and the floating gate below. The floating gate is therefore insulated *both from the control gate and from the body*. Now, another very important thing to know is that **current carries electrons**, **which** are actual particles that **can be put somewhere**. Because of the properties of the floating-gate transistor, you can apply a current (or equivalently a voltage) to place electrons in the floating gate **and they can't get out** until you apply a particular voltage. Even if there's no applied voltage (i.e. the device is disconnected from your PC or whatever), those electrons stay there. As a result, an appropriate voltage can put electrons in specific floating gates, thus writing 0s in specific memory cells, while all other cells represent 1s. Since electrons are stored in floating gates, they can't get out simply by disconnecting the device, and you can carry your SD card everywhere, knowing that it still contains your data.",
"SDs don't have it's own battery because it would be a poor design choice. Whatever you plug a SD into should have its own power source (if it doesn't, then you can't do anything with it). USB has four pins: data in, data out, power, and ground. The power pin starts drawing power from whatever device you're using when it's connected. You're question was a bit broad so I'm assuming you meant why it doesn't need a battery to transfer data or how it gets power."
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6qi1nf | How can tineye find a single picture amongst billions in a second but a 5000 row VLOOKUP in Excel takes much longer? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Hash indexes. They have a formula that converts an image to a number that uniquely represents that image ( eg: 565356773367447 ) and then they divide that number into the size of the index, which gives a smaller number, and that smaller number is the *address* in the database the image is stored at. So it boils down to INDIRECT(formula to guess which cell here), which is very fast, and importantly, does *not* have to compare against all other images. VLOOKUP however, by comparison, has to fetch every cell into memory, do a left to right comparison of your search and the cell. And that's slow and gets slower for every cell you add. Whereas the formula approach only spends it's time calculating the magic number, and then it only has to query *one* cell to see if there's a match or not.",
"Web services use lots and lots of computing power for indexing, processing, and searching. Vlookup is using a single computer and _part_ of the processing power in order to run your search. It's like asking an army to build 100 houses versus asking one guy to build 5. Even though the guy has a lot less work to do. The army will still be done faster."
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6qi6bb | When Amazon Video offers to show me a 1968 movie in HD for $1 more, is there actually any difference in quality? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Sure. Film in good condition is actually very high quality, better than HD. Quality was lost when SD media was made from it in the 1990s, so going back and making an HD version will result in a higher quality video.",
"Yes. In fact, most movies from 1968 are higher in visual quality than most movies from the last decade. Anything above low-budget indie productions was shot on 35mm film, and high-budget movies were often shot on 70mm film. It's only pretty recently that we've had digital video cameras that can exceed 35mm quality and they're still not that common. There still isn't a digital video camera consistently exceeding 70mm quality. Digital filmmaking became popular in the 2000s, but not because it provided better image quality -- because it was cheaper, faster, and more convenient. There are still a fair number of movies made on film, though it's decreasing each year. For example, *Star Wars: The Force Awakens*, *Jurassic World*, *SPECTRE*, and *The Dark Knight Rises* were all shot on film, and have roughly equal visual detail to a movie shot in the 1930s. Most video services mean either 1280x720 or 1920x1080 when they say HD. You can scan well-preserved film at 4-8 times those resolutions and still not capture the full detail present."
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6qj64r | What is the difference between free software and open source software? | Technology | explainlikeimfive | {
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"Open Source usually has some sort of license attached to it. So even though they \"freely\" show you the source code, there may be limitations or restrictions what you can do with it, as specified by the license. Truly \"free\" software in the Stallman sense means no claims of ownership, restrictions on use, etc. There are 4 specific criteria he uses * The freedom to run the program as you wish, for any purpose (freedom 0). * The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this. * The freedom to redistribute copies so you can help your neighbor (freedom 2). * The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this. URL_0",
"Richard is particularly against the Open Source movement because of the emphasis it places on the fact that the source is freely available. The OSS movement tends to focus on open-source software being superior because the source is open. It can be more rapidly-developed, bugs can be discovered more quickly, etc. The Free software movement (Richard's kick) is all about software being free because he believes it's a basic right and the \"right\" thing to do. Ideas should be shared, improved upon and re-shared, etc. Free software licenses (GPL) have stipulations that any new software based on it must also be free (the viral clause), whereas OSS licenses don't necessarily have this (allowing a company to use OSS software to produce closed-source software). Again, the distinction comes down to: should we use OSS because it's better, or should we use Free software because it's right?"
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6qjy9t | How does touch screen work? | Technology | explainlikeimfive | {
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"Whether it's resistive or capacitive, the concept is the same... There are sensors running across and up/down the display. When you touch the screen, you're either (resistive) pressing two thin sheets of material together, or (capacitive) disrupting the electrical field. The sensors pick this up and can tell where you are pressing. In the case of resistive ones, it detects where a circuit has been closed by where you pressed the sheets together. In the case of capacitive, it detects where the electrical field is distorted.",
"Resistive Touch uses two layers of material separated ever so slightly. Any force (finger/plastic stylus) can press down on the screen to register a \"touch\" = > This needs more force to register touch. = > Hence Not ideal for regular smartphone usage (sore thumbs). = > Preferred on tablets used \"on the field\" like construction sites, etc where accidental touches or liquid splashes could occur. (Because water conducts and registers as a touch on capacitive screens. Sometimes makes your smartphone go crazy) Capacitive Touch has an electric field (imagine a grid ) running across the glass display with the ability to measure where (i.e. intersections on the grid) exactly a conductor touched the display. = > The skin on your fingers conducts electricity and hence disturbs the grid to register a \"touch\" = > Requires a special conductive stylus unlike resistive screens that don't care what material you use. = > Really conveinent to use on a smart phone. (Happy to thumbs) There are many other technologies that enable a user to \"touch\" a screen such as INFRARED ( infrared lights being placed at corners of the screen with receivers at the other end. This data is used to calculate the position of your finger that blocks the path of the IR beam) but I assume your question was in respect to smart phones. Also look up [light pen ]( URL_0 ) if you're interested."
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6qkitj | Why is internet Explorer hated so much | Technology | explainlikeimfive | {
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"The hate mostly comes from Internet Explorer 6 which was a decent browser for its time. But Microsoft had crushed Netscape in the Browser Wars and saw little need to continue to innovate on the product and so they didn't. There were five years between IE6 and IE7: five long, buggy, security-hole-filled years. IE6 was a security nightmare and it was really common for new security flaws to be discovered all the time and Microsoft was really, really slow to patch them. It was also difficult to get patches out in the early days of the internet, so people could be running unsafe versions and never know it. It also lacked many of the innovations that smaller browsers were integrating at the time, liked tabbed browsing and pop-up blocking and addons/extensions. Another reason it was so reviled was because it was so integrated into Windows. You could open a File Explorer window and type a URL into the address bar and it would seamlessly switch the window to Internet Explorer. You can then do it to go back to file browser. Of all of the features of IE, I actually miss this one the most. But this integration made it really, really difficult for competitors to compete. When something is so integrated into the OS that you cannot even uninstall it without breaking the OS, how are you going to compete? That integration was another issue: IE often worked in the background, delivering web-based content to the desktop (Active Content, Active Desktop, etc) and so even if you didn't even use IE as your daily driver browser, you still used it without realizing it and you were still susceptible to its bugs and its security flaws. You couldn't even use Windows Update without using IE until a recent version of Windows (Vista I think) because WU was built on IE technology. IE also tried to break the web. Microsoft's design software for years (I don't know if they still do this), has been Triple-E: Embrace, Extend, Extinguish. Using this philosophy, they'd enter into some new software field (the Embrace), they would innovate and add features and stuff that doesn't exist in that field now (the Extend), and then Extinguish all of their competitors in the field because the community has grown dependent on the extensions they've added. This lead to an era where websites would work on IE but not work on Netscape or Opera or Firefox because it uses code, styling, or scripting that is exclusive to Internet Explorer. You'd constantly see these little badges on websites like \"Best viewed in IE!\" \"Best viewed in Netscape Navigator!\" It also hung around for a fuck lot longer than it should have, contributing to continued security issues in the modern era. Internet Explorer 6 was so bad and has had such a shit legacy that it permanently stained the IE name. More recent versions of IE aren't terrible browsers but it's become such a laughing stock that they've had to retire the name, hence Edge.",
"Speaking from a web developer's viewpoint, I have hundreds upon hundreds of lines of code that only exist to support IE. Chrome, Firefox, and even freaking Opera all work fine, but I have to have hacks to get crap to work for IE on almost every page of a functional website. I want to tell our customers that we flat out don't support IE anymore because it's exhausting testing IE and making hacks to support it, but there is always the 5% that insist on using it. Frustrating. As. Hell.",
"Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why does everyone hate Internet Explorer? ]( URL_5 ) 1. [ELI5: Why is internet explorer hated so much? ]( URL_0 ) 1. [ELI5: Why is IE so hated? Is it really that bad compared to chrome/Firefox? If so, why hasn't Microsoft improved in all these years? ]( URL_3 ) 1. [ELI5 Why everyone hates Internet Explorer so much? ]( URL_1 ) 1. [ELI5:Why do people hate internet explorer? ]( URL_4 ) 1. [Why do people hate on Internet Explorer so much? ]( URL_2 )",
"IE was notorious for accepting badly formed HTML, and allowing ActiveX controls to run, both of which were major security lapses.",
"Recently, Internet Explorer's been a bit decent again. However, old versions of it were infamous for being very slow, especially compared to alternatives like Chrome and Firefox, and for breaking many websites."
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6ql09e | Why is it that in many cartoon shows ranging from things like Family Guy and Futurama to Avatar: The Last Airbender and Invader Zim, during the early 2000's, CGI was so often used for some things although the shows were all 2D animated? | Technology | explainlikeimfive | {
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"I'll go into more detail. Let's say I'm working on Avatar. And I have a scene I wanna do where our heroes defend Ba Sing Se. So I want a massive army attacking the wall, and I want like thousands of soldiers. And critically, I want the camera to fly over this huge army and up the big wall and rest on my main characters standing on the wall who then have a conversation. Because it's cool looking. Well a simple background matte painting ain't gonna do that. I can't individually draw all the changes in background perspective as we fly over the army and up. That'll take a lot of time and manpower. But one guy can make a 3d model of the wall and do the flyover in a computer. They can also probably model the army. All I have to do is the detail work of Team Avatar standing on the wall at the end. Problem solved! Computer modeling of background elements has allowed 2d animation to be much less flat and much more dynamic. By adding a camera element that can move within the animated space, it gives storytellers new and exciting ways to communicate their visions. And it's cheaper now. Beauty and the Beast had one CG background elements. Aladdin had a few. Within ten years the technology had gotten cheaper to the point animated TV could use it at a reasonable cost. Especially in TV where speed is of the essence. Animated features can take their times but TV is all about fast turnaround. CG elements let you make your deadlines without compromising quality or vision.",
"It's just cheaper. CGI is faster, less expensive and more accurate (it just has a really hard time with organic objects, that's when you need an animator)."
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6qm4pl | Why some microphones able to record sound as long as it is loud enough, while some microphones only record sound when it is close to the source such as front of your mouth? | Technology | explainlikeimfive | {
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"There are a few types of microphones, which use different methods to change physical vibration into electricity, but I'll stick to the two you're most likely to see. First is the Dynamic Mic: it has a small, stiff diaphragm. A diaphragm in a mic is basically like a little speaker, but instead of vibrating and sending sound out, you cause it to vibrate with you voice or whatever and it sends sound *in*. It looks like an ice cream cone. This is what a singer on stage at a concert would use. It requires you to be pretty much right on it. Benefits are that it can handle very loud sounds without distortion, and isn't good at picking up other sounds nearby, so perfect for a vocalist surrounded by guitar amps and drums. Second is the condenser mic: particularly the Large Diaphragm condenser, which you'll see in a video of a singer recording in the studio. Also in videos of people doing voice-over work. It looks like a big tube, usually the same diameter from end to end. Benefits are: it's much more sensitive because of the larger diaphragm (and some other technicalities I won't get into), and it is better at capturing bass (think of the movie trailer voice- \"In a world...\". A drawback is, many condensers can't handle really loud sounds. I think the other poster was alluding to \"polar patterns\" or \"rejection patterns\". Microphones are desIgned to reject sounds coming from certain directions. Dynamics are usually designed to reject sound coming from the back of the mic. This helps make sure only the singer is getting in, and also helps avoid feedback. Condensers are often \"omni\", meaning they can pick up sound from all around- another reason for their extra sensitivity. There are other rejection patterns I won't get into for sake of simplicity."
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6qmgpr | Why does the download speed increase towards the end? | Whenever I download stuff via torrents, it begins slow, attains maximum rate and towards the end the rate shoots up. This happens just about when it reaches 95%. Is there a reason behind this? | Technology | explainlikeimfive | {
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"Torrent downloads begin slow because of three reasons: - You don't know as many peers in the beginning. For instance, when you just start the download, you know none, and the first packets that are being sent are just so that you can find peers that have the same file. - The peers are not convinced that you're trustworthy. The more packets you upload to a peer, the more packets the peer will send you. Since you have sent no packets at all at the very beginning, it may take a while for your client and your peers to trust each other, i.e. begin sending each other packets at high bandwidth. - BitTorrent often runs over TCP. In order not to oversaturate the network (it helps nobody to send 1 GB/s when you're on a mobile connection), TCP ratchets up the bandwidth. This effect also applies to HTTP downloads, and is more pronounced if your connection is lossy and high-bandwidth, for instance when using LTE with cars moving in between you and the tower. BitTorrent chunks the file into pieces (usually 256KiB), each of which consists of subpieces (usually 16 à 16KiB). At the end of the download, in theory it actually goes slower, because you now don't have a choice of which pieces to request, and if you're unlucky you and your best friends from above have the same set of pieces and are waiting for others. This used to happen when a release is very sudden and has only very few initial seeds (e.g. the first Ubuntu ISOs). It's not a problem when you download a little bit later, because by then most peers will have the complete file. BitTorrent includes an *endgame mode* to avoid that. Endgame mode is a fancy way of saying that your client requests the same piece from multiple peers. This wastes network bandwidth, but avoids problems where you're waiting for a peer under high load or one that has recently left the network. If your connection is the bottleneck, endgame mode will *decrease* your speed, because you'll get the same subpieces from multiple peers. Therefore, modern clients may not use it if they see that virtually everyone has the full file. If, however, your download speed was not limited by your connection, but by your peers, endgame mode may help, since you're now sending out more requests, and thus getting more answers. This is mostly applicable if you're not uploading much yourself, and thus likely to get snubbed by your peers. However, it's not very likely in your case - if you're not downloading in a high demand phase, BitTorrent downloads usually easily saturate any connection, especially if you're uploading yourself. What is likely happening is a **display artifact**: your BitTorrent client calculates the progress based on finished pieces, but not subpieces. There's a reason for this: Only the pieces are cryptographically authenticated. For whatever reason (disk / network data corruption, vandalism, etc.) you may have to redownload subpieces after receiving them. Therefore, if your client would show the progress in subpieces, the progress could move backwards from time to time. If you base the progress on pieces, then of course the download will seem to speed up. Let's assume there are 100 pieces and you have downloaded 84 of them. Then your progress is shown as 84%. That would be correct if you don't have any subpieces of the remaining 16 pieces. But if you already got 15 of 16 subpieces for all remaining pieces, your actual progress is 98%. With every incoming subpiece, a piece will get finished, so the displayed download speed will reach up to 16x the real one. A similar effect also exists on the subpiece level: On consumer networks, the maximum packet size (MTU) [will often be rather low ( < 4KiB)]( URL_0 ). If your client calculates progress based on full subpieces, the displayed progress will be incorrect if you have already some packets. For instance, let's take the above example with 1600 subpieces. If you have 1500 of them on disk, the displayed progress will be 93.75%. But assuming you are missing *just* one packet of each subpiece, your actual progress would be 99.61%. Every incoming packet will move the counter by 0.06%, when in actuality it only contributes 0.004% of the download. Both effects will be more pronounced if you're downloading from many peers concurrently. **The download speed is not actually increasing - it's probably decreasing - but the display is showing it that way**. From a user experience perspective, this may actually be desirable. Many progress bars (installer, file copying, downloads) are ridiculed when they correctly show that the last percent is often quite slow, even if that is correct. Much better to surprise the user with a quick finish."
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6qmjtb | why can't we reverse MD5 to generate the original file? | Technology | explainlikeimfive | {
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"text": [
"For one, a file's MD5 is much smaller than the file itself. For any given MD5 there are an infinite number of files that could result in that MD5 hash - actually *finding* them is extremely hard, but we know by the *pigeonhole principle* that they exist. Second, because not all steps can be reversed. In particular, any step that \"throws away information\" can't be reversed. As a silly example, do you know that game where everyone at a party says the name of their first pet followed by the name of the street they grew up on, and that's supposedly their adult performer \"stage name\"? The odds are that few people at a party will end up with the same stage name. But, given somebody's stage name (according to those rules) could you reverse those steps to figure out who they are? In general, no. Even if somehow you were able to access the first pet name and street name of every person in the world, there's no guarantee they'd be unique, and often they wouldn't be. So you can't easily reverse this. The same is true for MD5. MD5 is formed by taking bits from the file and shuffling them, and at many steps along the way, bits are thrown away in order to keep the size of the MD5 hash constant. So you can't reverse the steps because you don't know what those missing bits are, and therefore there are lots of possible files that could have that pattern. Keep in mind that MD5 was *designed* to be hard to reverse! So it's not just that it's hard but maybe with a lot of work you could find a pattern, it's actually pathologically hard by design - and even then there's still the problem of too many possible answers.",
"MD5 isn't a one-to-one function, it takes an input of any length and transforms it into 128 bits. This means that there are more possible inputs to the function than outputs, which means (due to the [pigeonhole principle]( URL_0 )) that there are multiple inputs with the same output. Given the output of the function, there's no way to know which of the original outputs it was. In addition, MD5 and other hash functions are designed to mix up the input and make it impossible to reverse the process. For example if I have two numbers and I add them together, there's no way of getting the original numbers from this sum - some information is lost along the way."
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6qoln7 | Why is it that analog broadcasts get snow/static the further you are away from the transmitter, but real-life sounds such as voices only get quieter without distortion the further you get away? | I can elaborate since this was worded poorly in my opinion, but it would probably come tomorrow as I'm going to be away from my phone and laptop all day. | Technology | explainlikeimfive | {
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"Because when the device isn't picking up a signal, it starts to pick up the signal of other things. Noise. It picks up electricity emitted by nearby objects, and electromagnetic radiation from other sources at random. Since this noise is being transmitted through something designed to interpret electromagnetic signals in a certain way (to create videos or sound) it is forced into that same state by the device. But its random, no pattern, so you only get odd noises or static. pixels randomly assigned colors when the signals carry no useful information. Because this interference is coming from everywhere, in different strengths and from different sources, it appears random. Since one of these sources is the [Cosmic Microwave Background Radiation]( URL_0 ) even being away from all other electronics will still result in this pattern. It doesnt happen to voices because they are being transmitted directly as sound, waves of pressure sent through the air, not being sent through a medium reliant on interpreting electromagnetic radiation and assembling it into a specific form.",
"Distance isn't the issue, noise is. When you receive the signal you are also picking up noise, as long as the signal is a lot stronger than the noise you can hear it clearly, but the further away it is, the quieter it is, and the harder it is to understand against the noise Consider standing next to someone talking while a fan is buzzing near you. While they're close they're loud, but as they get farther away they have to talk louder for you to hear them over the fan, eventually they're too far away for you to make out what they're saying over the noise of the fan. If you get rid of the noise (turn the fan off) you can hear them further away, but eventually even the quiet background noise is too much to understand them over"
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6qrdfe | If a hacker is able to intercept an encrypted file, what prevents him from intercepting the key as well? It needs to be sent too so it can be decrypted, right? | Technology | explainlikeimfive | {
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"> It needs to be sent too so it can be decrypted, right? Actually no, it doesn't. That's one of the great developments in cryptography. Public key encryption. The way it works is complicated but there is a simple analogy which can explain how someone can encrypt something with someone distant, and even if someone is in between they won't be able to decrypt it. Bob wants to send Alice a message. But if bob sends a message in a box, anyone can see it. So he sends it in a box with a lock, but how can alice open it? He can send the key as well but it's possible someone can get it. What's the solution? The solution is that Alice sends Bob the lock. Bob uses the public lock to secure the box with the message inside, and Alice uses her private key to unlock it. Anyone can use Alice's public lock, but only her private key will open things locked with it. This has a few risks, but far less than previous solutions: * The lock has to be unbreakable. Modern encryption essentially solves this, you can't break Alice's lock without the Alice's private key. * The key has to really be private. This is one route to break this encryption, but since Alice won't need to ever share her key with anyone it's tricky. * You have to make sure you are actually locking your box with Alice's public lock. This is a clever way people \"break\" this sort of encryption. They make you think you're using Alice's locks, but you aren't, you're using Charlie's, and charlie has the key for his lock. So he can unlock your message, read it, then relock it with Alice's lock, and send it along. This is a real security risk, and a lot of security is built around ensuring that you're actually locking your messages with the right lock, so they're safe.",
"Modern cryptography is built upon public key encryption. There is one key to encrypt, and one to decrypt, and having one doesn't help you with the other. The transmission goes like this: Alice: here my encryption key, which I don't care if everyone knows Bob: got it, here is a message encrypted with that key Alice: got it, I am now decrypting it my private key, which I keep secret If Eve is listening on the line, she can get Alice's encryption get and the message Alice sent to Bob, but that does her no good in decrypting the message."
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6qtdax | What makes 70mm film screenings different? (i.e. Dunkirk) | Technology | explainlikeimfive | {
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"text": [
"For one, it's not a digital projection. Most movies you go see in a theater are projected digitally, but if you had gone 15 or so years ago, they would have all been projected with film. There is an ongoing debate about which is better. Digital tends to show a cleaner picture, but the detail is limited to a certain resolution and film tends to have richer colors and blacks, but with some minor imperfections in the picture. It's sort of similar to the debates about whether sound quality is better on vinyl records than it is on digital files. Anyway, if you had gone to see a movie back in the day, in most cases it was on 35mm film. Dunkirk is being shown on some screens in 70mm film which means that the individual frames are larger and thus have more detail.",
"In terms of color and dynamic-range digital sensors come close to the performance of film. However in terms of resolution, digital is nowhere near film. 70mm has a resolution of about 18,000 horizontal lines. For reference 4K is 3840 and HD is 1920. [This image]( URL_0 ) gives a visual comparison of various sensor sizes, the largest digital video sensor sold today is the RED Dragon 8K shown in red."
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6qu23o | How does digital compression work? | I know how physical compression works. If you compress say a gas, the atoms basically get squished closer together... but how is this achieved in a digital environment? And more importantly how is to achieved without any data being lost? To clarify, I'm not talking about things such as video or audio compression, I'm asking about the process of making actual digital data occupy less digital space (think winzip) | Technology | explainlikeimfive | {
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"Imagine a tool box or a sewing kit, any of those need little storage devices with cubbies and drawers and little fold-out shelves. How much space to they take up? When they are stored away, they take up very little space. You open them up and take all the little bibs and bobs out to use, and they take up a more space. And once you're really get into your project, and have things spread out all over your workbench, they take up a lot of space. There is really no one right answer to how much space it takes up, because it is really a tradeoff between space and accessibility. Information in a file, like a story, a song, a picture, or a movie, works the same way. It can be very accessible, and take up a lot of space, or take a lot of work to get at and be packed away tightly. There is really no magic to making it smaller, you are just making the same tradeoff between size and accessibility. When you transform a file into the small but less accessible format, we call that data compression. There are two kinds of data compression lossy and lossless. With lossy data compression, you are actually throwing out some of the less necessary data. A lot of it based on human perception. The ear is less sensitive to very high frequencies, so eliminating the data associated with that would go largely unnoticed. The eye is more sensitive to brightness than color, so it is hard to tell the difference if only half the colors were used. Lossy data compression techniques usually have a quality setting, that instructs the algorithm how much data to drop. At the lowest quality, size becomes very small, but the differences become more noticeable. When you cannot afford to lose any data, like with an executable file, you must use lossless compression. It works by removing redundancy (sometimes called entropy) from a file and encoding it in a more efficient form. Text files are normally encoded using something ASCII, where each letter is assigned an 8 digit binary code: A = 01000001 B = 01000010 C = 01000011 etc. With this scheme A, a common letter, takes up the exact same amount of space as Z, a less common letter. Even worse, the word \"the\", takes up three times as much space as Z, even though it is more common as well. Lossless data compression figures out which sequences are most common and assigns them shorter codes, leaving longer codes for uncommon ones. It might encode An as 1101 and Z is 1001100111. For every A it encounters, it saves 4 bits, but for every Z, it uses 2 more. Overall this is a big win because there are going to be more A's than Z's. One frequent question is why can't you just compress a file over and over until it is as small as you like? When you stow your tools and fold up your tool box, it becomes optimized for space, there just isn't any more space to remove. Similarly, lossless compression removes redundancy and optimizes how data is encoded so it takes up less space. Once you remove it once, there is nothing left to remove. .",
"From what I understand it's more or less Algorithms that find redundancys in data and instead of IE 01010101 it's condensed into 01x4. Pretty simplistic I know but that is the gist of it if I understand correctly.",
"Losless compression essentially boils down to finding patterns in data and storing that pattern, instead of the original data. For example, take a stream of twenty bytes like the following: > aaaaaaaaaaaaaaaaaaaa In this situation, it's easy for a human to see the pattern: this is 20 times the letter \"a.\" Storing the concept \"20xa\" takes up less space than the original pattern. Lossless compression algorithms find such patterns in more complicated ways, transforming them mathematically to take up less space. The downside is that taking the mathematical pattern and calculating what the original data was can take a lot of processing time, because many calculations need to be performed. Human languages display some patterns and so make for good compression. Even the binary code for a program is repetitive in some ways. Even though video data is highly patterned (one frame is mostly the same as the previous frame), it's usually already stored in a compressed format, so you won't compress it more by applying another algorithm. A side effect of the fact that compression algorithms are based on finding patterns is that truly random data cannot be effectively compressed without losing some of the randomness. On the other hand, by definition, random data contains no information--it's usually not worth storing."
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6qu6nr | Why can't GIFs be stored/compressed in the same way videos can? | Technology | explainlikeimfive | {
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"Because then they wouldn't be GIFs. A GIF is a specific image format that uses a specific set of techniques to compress an image and represent multiple frames. Those techniques are very cheap to decompress and thus was very good for the early internet when computers weren't very fast. Modern video formats use several different techniques together for better image compression, most (all?) of which the GIF image format does not support. They also require significantly more computation to decompress, with several video formats actually using specialized hardware on your device or computer to play back as they could otherwise be too expensive to play back in real time! The basic explanation of the GIF compression format is that it uses indexed color. A table of up to 256 colors is stored for each GIF with the pixels of the image only storing what color index to use. If multiple pixels in a row use the same color the format just stores the one color index and how many pixels after that use the same color. You can think of it as a digital paint by numbers. For multiple frames of animation, each frame generally only stores information about pixels that changed from the previous frame, and uses a single \"transparent\" color for the other pixels. This can often mean much of each frame after the first is almost blank if not much changed. Then there's a little information about how long to display each frame and how many times to loop the animation, and that's kind of it. It is possible to change or add to the GIF format, looping wasn't originally a feature for example, but there's little reason for anyone to spend the time doing so when there are other formats that already exist. It would also require getting browser and content authoring tool developers to support those changes.",
"GIFs were never meant to store video. It is an old format designed to store still images and small short animations. A 200 x 200 pixel half second animation was the most it was designed to store, and so GIF doesn't do well to store modern high resolution silent videos. In video, most of a frame is the same as the frame before it. Most notably; in stationary shots, the background stays the same. To save space, you only need to store the changes between one frame and the next. This is the basis of inter-frame compression, and how modern video compression works. If something stays the same, you don't have to send it again. GIFs don't have inter-frame compression. It only has intra-frame compression. There was no need for it back when the format was designed. Each frame of a GIF is compressed by itself, without taking into account information from the frame before it. So whichever part of the video stays the same between frames, has to be stored again each frame. This makes GIF a much less compressible format for video than other alternatives. Edit: Had inter and intra backwards.",
"They *sort of* can. There are clever gif making programs out there that make each successive frame in a GIF image transparent, and only make it contain parts of the picture that have changed from the previous frame. That is very basically how video compression works. The standard answer though is that gifs define each frame in full, whereas video formats don't, they only define the stuff that's different on each frame."
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6qwdjq | The differences between WiFi, cellular data, and Bluetooth on a technical level? | Technology | explainlikeimfive | {
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"They're all ways to communicate by radio transmission. Really the difference at base level is what frequency and what protocols they use. At the physical level, they're all the same as your car radio.",
"Different frequencies, different packet formats, different message protocols - essentially they have nothing in common except that they are radio signals. At least they are all digital (unless you're in a very old cell phone regime) so they are more reliable than the AM radio in your car.",
"Let me expand on what /u/WRSaunders explained: There is a lot of detail hiding behind a simple name such as \"WiFi\". Although those you mentioned all use radio frequencies, radio is by nature analog (continuous) and must be converted to and from a digital (discrete) result. A protocol defined under a name like the ones you mention makes some reasonable but arbitrary choices that everyone has to agree to in order to communicate. For example: * Radio frequencies-- which ones and how signals on each are coordinated * Signal timing-- how much space between chunks, and between bits * Signal encoding-- how you convert digital numbers into analog signals and back * Error detection, correction, and recovery-- usually very necessary in a radio environment * Encryption protocols-- how to keep signals secret from unwanted listeners * Packet encoding-- how your data is combined with metadata so that it can be tracked and managed This is by no means an exhaustive list. But because there are so many components that make up a standard, usually they are completely incompatible with one another-- having a WiFi transceiver won't allow you to talk to your cellular phone tower. *Edit: clarity, clarity, clarity*"
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6qwta9 | Which is better, a 2.4 GHz single core processor or 1.6 GHz dual core processor? | Technology | explainlikeimfive | {
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"Impossible to answer. Clock speed itself doesn't determine how \"fast\" a processor is. A 2.4Ghz Pentium 4 isn't the same as say, a 2.4Ghz i3 even if we pretended the Pentium 4 had two cores like the i3 would. Dual core processors are better at multitasking and multithreaded applications. If the processors are otherwise identical, you'll always get better performance on the dual core processor as some CPU time is always being used on OS-level tasks. Edit: If you really want to know what processor has better performance, you're going to have to [rely on benchmarks]( URL_0 ) and even then it won't tell you the whole story.",
"Imagine you have a large group of sheep and a task to count them all. If you have one man who can count 2.4 sheep per second (not more, not less), the only option you have is to simply count all sheep normally. They might optimize one way or another, but they are doing all the work themselves at the predefined speed. Now what if you have two humans, younger ones who can count only 1.6 sheep per second each. You can simply divide the sheep into two groups and each man counts their own group, and then the results are simply added together. You can guess that the group of two will do the work faster as they can do it in parallel. The same happens when a computer program can do parallel computations. However, it is not as simple as it sounds to write software capable of doing so, and very often tasks cannot be parallelized. In those cases the second guy would stand by idle doing nothing, and the overall performance of a single 2.4GHz guy is faster than 2x1.6GHz.",
"\"Better\" for what? If you want to open the case and make cufflinks out of the die, the dual core one will have an interesting repeat in the pattern. The faster one does math faster. That will make some programs run faster. The dual core one can sometimes do two things at once, which is good for programs specially constructed to utilize multiple cores and not good for other programs like MSWord. Memory, graphics, storage speed, and other things impact how fast a computer is, and it can almost never be simplified to the extent you desire.",
"It's hard to say. The GHz number is its \"clock speed,\" which measures the number of cycles per second the CPU can run. So a 2.4GHz CPU can run 50% more cycles per second than a 1.6 GHz CPU. But that's not as helpful a benchmark as it seems. And that's because different processors can get more *done* per clock cycle. If your 1.6GHz CPU can do twice as many things per clock cycle as the 2.4GHz one can do, then the 1.6GHz is actually 33% faster than the 2.4! Also, every cycle uses power and generates heat that must be dissipated. If it gets too hot, the CPU won't run as fast. So a CPU getting more work done with fewer cycles can also run closer to full speed. So we'd need to know more than the clock speed of these two processors. We'd need to know how efficient they are. We'd also need to know what the processors will be working with. How much memory is available to them? How slow is the hard drive/SSD? It's all well and good having an engine capable of a thousand miles an hour if the wheels can't go more than 60. For about a decade now, clock speeds have leveled off. But efficiencies have improved dramatically. In other words, unless you're comparing some really old computers, the GHz isn't the number you should be looking at any more.",
"The cache / application and Os will play their parts too, 9 ladies can't have 1 baby in one month, but ten guys can drink 10 beers in 10 minutes !",
"Assuming both processors have a task that can be divided into two equally hard tasks both processors would perform equal. If the task is not dividable perfectly the single core would be faster, as the seconds core would be waiting after it’s task is finnished. Power comsumption wise the dual core is better as driving 2.4 GHz needs a higher voltage than 1.6 GHz. A home computer or smartphone with a single core processor is bad because it does a lot of stuff in the background, so uncompressing a downloaded update can make the whole system unresponsive."
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6qz1bd | How did the police catch speeders before radar? | Technology | explainlikeimfive | {
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"Have you ever been driving down the road and seen white patches on the road? Those patches are an equal distance apart. The police would time how long it took a car to get from one patch to the next. Multiply that out and you've got how fast they were going. There were other ways they did it, as well (such as just using other stationary references they knew the distance between, or if the officer was driving also, timing how long it took for the car to pass them/some other spot).",
"They followed the car and matched speed. If their spedometer was above the speed limit, they knew the car they were following was speeding."
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6r12mb | How are cable standards such as USB and HDMI created, and is the party responsible receiving royalties? | Technology | explainlikeimfive | {
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"The USB Implementers forum manages USB. Currently there are licensing fees if you want to get your chip certified for USB or use the USB logo on your devices but they're relatively cheap and you can buy other people's USB chips super cheap. USB was created when Compaq, DEC, IBM, Intel, Microsoft, NEC, and Nortel got together in 1994 and decided they wanted a common connector that most things could connect to. Those were the powerhouses of the day, when they all decided they liked this and wanted to use it then it was going to show up very quickly with Microsoft adding software support for it to windows, and the rest pushing the hardware. HDMI is a similar deal, created by Hitachi, Panasonic, Phillips, Silicon Image, Sony, Thomson, RCA, and Toshiba. So that's like 85% of the TV and monitor market right there. They built it off the already widely accepted DVI standard which made adoption a lot easier"
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6r1pka | Why did most televisions, and screens in general, have 60hz refresh speeds when the standard for movies and TV shows was 24 frames per second? | Technology | explainlikeimfive | {
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"The 60hz Television signal was chosen in the US because AC electricity in the US runs at 60hz. In the early days of electronics there weren't any inexpensive ways of keeping a consistent frequency, so many electronics relied on the AC power frequency to keep time. This included early electric clocks! As television became a thing it made sense to keep using that same technique, and it meant Television sets and Television cameras were always in perfect sync too as in the early days they didn't have ways to record video, so all television was done live! So why is US AC power run at 60hz? As best as anyone can tell it's because the Westinghouse Company (an early American power company) thought it's existing lighting products looked best when running at 60hz, and because the competition (Edison) ran at 50hz. Really though no one knows the for sure why 50hz and 60hz were chosen. Westinghouse eventually \"won\" and for the US at least everyone else followed suit. In Europe they use 50hz as their standard, and is why their Television signal is 50hz instead of the US's 60hz. Since Europeans colonized much of the rest of the world (or were easier to trade with) most other countries also adopted 50hz AC and thus 50hz television. (US TV is actually now 59.94 hz, but that's a longer conversation.) Movies have traditionally been shot on film, and film is expensive, so using as little film as possible while keeping a smooth image was the goal of early film makers. Early films ranged somewhere between 12 fps to 60 fps depending on how fast the camera operator cranked the camera. Yes, they were hand cranked back then. Today it's hard to know exactly how fast to show films at because some were deliberately under cranked to speed up the action when played back (again, hand cranked) at around 20~30 fps. After a lot of experimentation films eventually landed on a standard of 24 fps as it was a good compromise in motion smoothness and film usage. In both cases as the technology progressed such that keeping 60hz or 24fps wasn't necessary, so much of the existing hardware and tools relied on those rates it didn't make sense to change them. As such we've been stuck with them until only recently as pure digital content has taken over and we no longer have to rely on every television only being able to accept a 60hz signal. Most US TV shows are actually 30 fps (actually 29.97 fps, again, longer story), and not 24 fps. When movies are shown on TV in the US they use what's called a 3:2 pull down, which basically means they basically show some frames of the movie twice and some frames once so that the timing isn't affected. In Europe they just play movies back at 25 fps. An average hour and a half long movie ends up about 3 minutes shorter if you watch it on TV in Europe. edit: said \"cameras\" twice."
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6r3phk | How come airlines are able to stream live satellite TV to their entertainment systems, but have trouble providing stable on-board internet access/Wifi? | I'm on a Delta Airlines domestic flight at the moment, watching live TV. Wifi however, is terrible. Doesn't beaming TV to the airplane require much more bandwidth than beaming stable internet traffic? | Technology | explainlikeimfive | {
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"Beaming TV to the plane is a one way connection. WiFi and Internet require asking for data and waiting for the requested data to arrive, then asking for more. Satellite TV is just a constant stream of data, just show what you get. Missed a packet? Too bad, pick up from the next keyframe. Don't want the data? Turn off your receiver, it'll still come to you though, you just won't decode it",
"A live tv broadcast is probably already being transmitted from space through the atmosphere to earth and the plane just has to pick up that signal once and show it on all the screens. On the other hand, proving stable internet access requires a dedicated two-way connection to the satellite that must be shared with all other users (not just the plane passengers) and every video streamed requires its own bandwidth to send, which results in very expensive access costs so the plane operator has to limit the capacity of each plane."
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6r3wo4 | Is there a reason why phones record the time you've spent during a phone call? | Technology | explainlikeimfive | {
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"Back when cell phones were very knew you were charged a set amount of money and you got a set amount of minutes with your plan. And so by knowing your whole time you knew how much you would use during the month. And if you had gone over and used more phone minutes then what your plan gave you, you were charged a certain amount usually $.40-$.80 per minute to talk. So people would do what they can to limit the call.",
"Back in the day you used to be charged per the minute. Some people still pay for maybe 500 minutes a month and it's a way for them to keep track. If an employee gives an employee a phone and say hey we want you to be on the phone for 240 minutes a day, they would be able to track it."
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6r4owf | How do people create viruses without constantly fucking up their own computer? | Technology | explainlikeimfive | {
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"In the early days of hacking, viruses were created on test computers. A machine that has all the basic components of a computer, but doesn't have anything but an OS installed. It's just a dummy. Later, we created virtual machines for that. Basically, a whole computer that is separated from the rest of your computer by an invisible wall. This is how most viruses are created nowadays. However, certain particularly nasty viruses can get through even virtual machines. We're back to using dummy computers that aren't connected to anything else.",
"Generally they test the code on a virtual machine, which is basically a copy of the operating system running in a \"box\" on the computer. Successfully infecting the OS inside the virtual machine doesn't actually infect the computer. If the malware is intended to target specific hardware setups you can always just infect a test machine too, then wipe it clean since it wasn't storing anything important.",
"A virus on a computer isn't the same as a virus in your body. Just having code for a virus doesn't make your computer radioactive and unusable. As long as you don't execute the virus on your own PC, you won't have any problems. Additionally, to test it, you can just test it on a separate machine, or a virtual environment within a system that prevents it from getting outside of that. All depends on the type of \"virus.\"",
"In lieu of starting another thread for the question, what is the point of making viruses? Just to be a nuisance? Is there a real reason behind it?",
"By using the most effect means of protecting yourself against viruses...frequent backups. You basically get really good at restoring your computer from a backup quickly. It a physical machine, there is software that can do that in less than an hour, and with VMs, you can do it in seconds."
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6r617c | Why does Pandora think Louis Armstrong is related to Led Zeppelin? | Luis Armstrong and Ray Charles come up constantly. Nothing against them, but if I'm in the mood for Zeppelin tunes, I'm thinking CCR, not "What A Wonderful World". How does even a computer make this kind of connection?! | Technology | explainlikeimfive | {
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"Zeppelin got sued years ago and had to give publishing credit to Willie Dixon. Pandora's algorithm sees his name and associates it with Armstrong."
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6r63qp | Why do we have fancy unhackable standardized lotto machines but when it comes to voting we're still in the 1980s? | Technology | explainlikeimfive | {
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"The major difference is the voting system cannot provide the voter with proof of their vote. That would make it possible to buy votes. A rich, bad actor, could offer $X for each person's proof they voted a certain way. With this limitation, many technically feasible solutions for accurate and safer voting systems are off the table.",
"Skip the lotto machine example (yes, they're hackable!) and substitute ATMs. Because Diebold, the same company that ~~makes~~used to make a lot of electronic voting machines also makes a lot of ATMs. So: why have we had seemingly error- and fraud-proof ATMs since the 1980s while electronic voting is such a mess? On one hand, banks are sophisticated, well-resourced commercial entities with a profit motive. They have paid a *lot* of money over the years to ensure that ATMs are, from the user's perspective, largely fool-proof, and they're in a position to insist that ATMs work perfectly each and every time (or close enough to it). And however many banks there are, all of them participate in one of very few interbank networks, most of which rely upon a defined [ISO standard]( URL_0 ) financial transaction messages, making things a lot easier. Oh, and there are probably millions of financial transactions per day, all of which fit the same pattern: take money from *this* account and either put it in *that* account or dispense it as cash. On the other hand, elections are conducted by literally *thousands* of individual municipal governments, all of which are constantly hurting for funds, that are not subject to any kind of standardization even on the state level, let alone the national level. The constitutional structure of the United States--both federal and state--makes it almost impossible to change this. And elections happen no more than once or twice per *year*, but they're all different. Different offices, different candidates, and even different *numbers* of candidates. And don't get me started on things like referenda. So you've got an arbitrary number of decisions to make, with an arbitrary number of options for each decision, for each and every election *on the municipal level*. Paying to have ballots printed is bad enough. Paying to have ballots *reprogrammed* would cost one hell of a lot more. And this for entities that barely do anything nine month out of the year. That's why.",
"Why would you think lotto machines are unhackable? Pretty much anything is hackable, with or without physical access. URL_0 URL_1 As far as voting goes, most regulations (including how votes are gathered) are determined at the state level in the US so standardization is very difficult to do. Also making sure it's clear to you that there's no concrete evidence any votes were changed - this aspect of most voting machines and systems are fairly secure (but again, not unhackable)",
"Voting systems need to fulfill a lot of criteria: 1. each voter gets one vote only 2. the voter needs to verify that their choice was recorded correctly 3. no one can find out a particular voter's choice 4. voters can monitor the counting process if they so choose With paper voting: 1. you get official ballot paper at the polling place, mark it, then hand in the notification card you got in the mail and throw your ballot into the urn. Three people watch while this happens. 2. you can immediately see where you marked the paper, if you make a mistake, you can get a new paper. 3. after the ballot has been thrown into the urn, it becomes anonymous. For good measure, the urn is shaken after sealing, and before unsealing. 4. you can go to the polling station and sit in a long line, where all the ballots pass through, and make your own tally. With machine voting: 1. the official enables the machine after verifying your eligibility. Three people watch while this happens. 2. the machine shows what you pressed. You have no way of verifying that this is recorded correctly. If you make a mistake, there is no way to correct it. 3. the order of ballots is recorded, so an observer could count people going in and de-anonymize voters this way. 4. you can go to the polling station and verify that the recorded data and the final tally match. Due to 2., there is no way that this must correspond with the actual votes. The machines are also very expensive compared to paper ballots, which makes allocation of voting machines to districts a hot topic. There have been several instances of large districts only having a single machine, which led to hour-long queues, putting anyone who was unable to take an entire day off at a severe disadvantage (in addition to several polling places closing before everyone voted). In short: you cannot have a constitutionally sound election with voting machines, and with enough volunteers it is entirely possible to run an election without them. Don't fix what ain't broken.",
"When it comes to gambling they care because there's tons of money to be made. When it comes to voting they don't care because there's tons of money to be made.",
"Reminds me of one of my favorite quotes, from the head of the IRS: \"People ask me why the tax code is so complicated. My answer: because it's real money.\"",
"The problem is that that voting have requirement that lotto machine or a ATM done have anonymity Loot at at a essay by Bruce Schneier [What's Wrong With Electronic Voting Machines?]( URL_0 ) on the subject. It has four main requirements quoted in full below. The problem is to have both accuracy and anonymity is hard. A ATM have no requirement for anonymity but the opposite since all transaction has to be connected to a person. > Accuracy. The goal of any voting system is to establish the intent of each individual voter, and translate those intents into a final tally. To the extent that a voting system fails to do this, it is undesirable. This characteristic also includes security: It should be impossible to change someone else's vote, stuff ballots, destroy votes, or otherwise affect the accuracy of the final tally. > Anonymity. Secret ballots are fundamental to democracy, and voting systems must be designed to facilitate voter anonymity. > Scalability. Voting systems need to be able to handle very large elections. Nearly 120 million people voted in the US presidential election. About 372 million people voted in India's May 2004 national elections, and over 115 million in Brazil's October 2004 local elections. The complexity of an election is another issue. Unlike in many countries where the national election is a single vote for a person or a party, a United States voter is faced with dozens of individual election decisions: national, local, and everything in between. > Speed. Voting systems should produce results quickly. This is particularly important in the United States, where people expect to learn the results of the day's election before bedtime",
"Why isn't a block chain system implemented for voting?",
"Just to address the elephant in the room that nobody has mentioned yet; A lot of people in America think that voter IDs are racist and designed to hurt minorities. In my experience (IT computer guy) having each person authenticate into the system using their ID would make it a lot more difficult to buck the system, if it is designed properly. One vote per ID, make it time consuming to get the ID, and that should thwart MOST voter fraud as well as make things more modern. This is very expensive though, as other people have said: money is a big reason why The voting system we have now is, as you said, outdated.",
"Great, an ELI5 I can tackle. I work in infosec and specialize in offensive security (penetration testing, break-ins, doxxing, etc.), so I have experience in how hackable devices tend to be. Since you're likely referring to the voting machine hacking expo at this year's Defcon, I'll talk about that first. The voting machines present during that event were of several varieties and software, which meant that some were easier/harder to hack than others; in fact, the easiest one to hack took only 90 minutes! One thing that many people overlook though is that the first machine was already retired and not in use in actual elections—the machine was running Windows XP as its base operating system, and in the cyber security world, Windows XP is the mother of all Swiss cheese. We like to say that if you hook an XP box to the internet, it's already been taken over, simply due to how many automatic scripts are just crawling around online and looking for XP machines to infect. So that box was cracked after running a pre-built exploit to get into it, and wouldn't be used in an actual election. Other boxes, however, had exposed I/O units (specifically USB ports), which would very much be an issue. If you wanted to hack these and had the resources (i.e. the software beforehand in order to write a script to hack it), you could plug in a Rubber Ducky (which is essentially a flash drive with a processor that will run whatever script you want and trick the machine into thinking it's a keyboard) and change whatever you want. However, voting machines use proprietary software and utilize the practice known as \"security through obscurity.\" Nobody has access to voting machine software, ergo nobody can go ahead and configure an exploit to break in with. If you want to do it on the fly, you'll need to bring a Raspberry Pi, a screen, a keyboard, a mouse, and a power source with you to the voting machine and then hope that the machine has USB ports and t*then* hope that you can hack it within ten or so minutes (yes, you can technically take as long as you want but people will get suspicious and figure out you're not trying to decide the fate of your country). So on that level, they *are* secure because they removed two things: extended access, and understanding of the inner-workings. It puts you into a time-limited black box, which means that your hands as a hacker are essentially tied. Hackers try to attack the weakest point of any system and voting machines simply aren't that point. It would be way easier to compromise people, or even faking paper ballots rather than trying to break into the boxes. Now, the question on why the security is better in lottery machines (assuming equal access to both) is for a few reasons. The top reason is that lotto companies have a financial incentive to maximize their security, which will prevent them from losing both money and integrity with consumers. To call them \"unhackable\" may be a stretch (I wouldn't know—I haven't tried), but it's possible. A lot of hackers/pentesters will tell you that \"nothing is unhackable! Everything is vulnerable!\" The truth of that is that technically a system *can* be unhackable, but the point they're trying to get across is that those are so rare and infeasible to create, they might as well not exist (people are the weakest part of any system, then the services the technology is running, then finally the technology itself). Tangent aside, the government, unfortunately, is not quite as motivated by election integrity as companies are by money. Human greed is a huge driving factor and manages to make a lot of the things we have work, since everyone wants to make more money. The government may or may not have our best interests at heart (I don't want to get political here), but the sad truth is that they don't really know how to pass legislation to ensure the machines are secure, and don't really desire to do so. They're not tech-savvy, and don't ask people who are (though if any congressman is reading this, I'm available~). So overall, not much gets done in the way of security. The companies that make the machines are going to get paid whether they secure them well or not, so it doesn't really end up being their concern. And even if both they and the government wanted to, they'd run into one of the biggest issues the government faces, being that it's not exactly the fastest thing alive. Even if they wanted to deploy security patches, there's no telling how long it would take the government to put procedures in place to effectively do any of that on any level. But fortunately, there's no need to fret, because the voting system *is* remarkably secure for what it is! I previously mentioned that the machines aren't the weakest point in the system, and fortunately, we've done a lot of non-tech things to make the system as a whole more secure. The boxes aren't connected to the internet, people do a lot to ensure that nobody that isn't trusted has access to the boxes, the boxes are being monitored until the government counts the votes, etc. It's not a perfect system, of course, but the government does do a decent job at gardening the system as a whole, even if the software leaves a bit to be desired. One of the biggest issues is that they end up leaving it open to a Man-In-The-Middle Attack, where a trusted party ends up compromising the integrity of the data. Fortunately, the way that pre and post-voting is set up makes it difficult for any rogue hacker to get into the broader system and start tampering with stuff. However, the way that the code is set up does mean that the machines are very vulnerable to attacks by the manufacturers themselves. They have the source and we have no way to review that, so they could weigh the votes 55% for one party and 45% for another and we would have almost no way of knowing (we could find out, but it would be difficult). So if the companies that manufacture the voting machines have a vested interest in one candidate and are willing to violate some extremely serious laws (treason-level), then yes, they could feasibly tamper with the results and make their individual come out on top. But to do this would require wide-scale integrity-compromise and probably wouldn't swing the election unless you were able to corrupt the other voting machine companies as well (in the case of a national election), or your state happens to be able to swing the result, if the results happen to be close. Opinion Time: I think that voting machine software being vulnerable to anyone, even to the manufacturers, could be solved if the software were made open source and available to everyone to review. If people can submit but reports and then the developers *actually fix them,* you can end up with some highly tamper-resistant machines that aren't in danger of being manipulated by the programmers themselves. Do a full-audit of every voting machine after the election to ensure that the software is correct, and you now have a system that is secure through exposure and trials. The downside is that if someone finds something big, they could theoretically hide it and save it for the election, given that nobody else finds it. But just put all I/O ports on the inside (or encrypt the communication channels so only special machines can actually interact with the software at all) and then place a tamper alarm on the physical box and you should be good to go. I don't think that electronic voting is inherently a bad idea, and I also think that it has some tremendous benefits compared to paper voting. But as are many things with the government, a good idea is turned into a poorly-implemented one due to incompetence, greed, or some other factor that corrodes the original intention of the concept that was introduced. I hope this answered your question sufficiently. Let me know if you have any others and I'll do my best to answer them!"
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6r6cur | Why is the USA so slow in adapting technology but many, if not most of technology breakthrough comes from this country. | I heard some of the reason being political. The huge land may also be a factor. However I feel like there is more about it. There isn't much of a "request" from the public. People seems to be fine with one of the worst subway system in the world. And they are still using ancient magnetic stripe card which probably no other major city is using. When I came to the States more than 10 years ago, the high school was using VHS tape for educational video. In Hong Kong, they were "already" using DVD back then. Why is there such a wide technology gap from the inventor to the general public? | Technology | explainlikeimfive | {
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"> People seems to be fine with one of the worst subway system in the world There isn't a US subway system, there are a bunch, but they're under city or state control. > When I came to the States more than 10 years ago, the high school was using VHS tape for educational video Again, school resourcing is done at a state and local level. There isn't a unified body of government. The US is a massive country with a large population and a bunch of different political entities that often slow down development. Technological adaption is quick in the US, but there are many people and areas that are slow to change due to culture, education, availability to the new technology and other factors. We're not a monolith.",
"\"the high school\" like there is just one here. There are thousands of them and they largely reflect the wealth of the surrounding community. Some have state of the art everything. Others can barely afford books. If you are referring to the NYC subway, that thing runs 24/7, serves millions of people every single day, and still only costs $2.50 per ride in a city where you can't get someone to spit on you for less than $5.",
"Why would you upgrade to DVD if your VHS tape accomplishes the educational goal? Many things in the USA with tech work this way - huge borders mean things roll out slower and are more expensive to replace, and there is no top down authority forcing change."
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6r7ugd | How is a phone able to be charging and using the battery at the same time? | Technology | explainlikeimfive | {
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"The current required by the phone in order to run is less than the current supplied via the charging cable. You are not actually using the battery and charging it at the same time, the phone takes the power it needs to run from the mains and uses the rest to charge the battery. It's not possible to charge and discharge a battery at the same time.",
"Think of electricity as water. If you fill a tub of water faster than you drain it, it'll still fill just not as fast. As long as your phone isn't using more electricity than the charger is providing it, it'll charge."
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6rb0at | The difference between a router and a smartphone's hot-spot. | Technology | explainlikeimfive | {
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"From the perspective of the computer connecting to them, there is no difference. The differences lie in the capabilities of the router for providing \"extra\" features, like configurable IP address assignment and NAT - but the actual *WiFi* portion of what they do is the same. The router might (or might not) have multiple radios or multiple antennae, though, and that would allow it to handle more devices at once, at higher speeds, than the smartphone ever could."
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6rf5nk | How do games with special anti-piracy features know who pirated the game? | A bunch of games have special features that get introduced to the game if a pirated copy is detected. Serious Sam 3 has an invincible pink scorpion, Mirror's Edge stops you from gaining momentum, and The Witcher 3 inserts slavic grandmothers into all the sex scenes. How do the devs tell if a copy of the game has been pirated or not in order to selectively unlock these features? | Technology | explainlikeimfive | {
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"While the checksum-method /u/Snackys mentioned is most likely one of the more common ones, there are also some other methods: For example, the developers of the game \"Game Dev Tycoon\" released a \"cracked\" version themselves as a Torrent which had some modifications to it - so they did not need to detect which game was pirated and which not but they knew upfront :) For more details, see their blog: URL_0",
"One of the features game developers use to identify if any contents of the game has been modified from what it should think it should be is called a checksum. In a hypothetical, a checksum would look at the games files: \"Is file A this many KB? Does it have XYZ for the first few lines?\" and whatever it looks at spits out numbers and letters. This algorithm makes it so a file with any little 1 or 0 out of place would spit out a different end number. The checksum knows it should spit out a specific string of values and if its different it knows its wrong. From here you can go as fancy as you like but thats the basics. This technique also what validates files you download from the internet in case you are wondering. So now that we have a checksum, the game developers can put a code where the game will change its files and code if the checksum is incorrect. Since pirates probably dont have the time to fully test out the game, or know every exact mechanic of how it should go, things like you mentioned above happen. When the pirates get in depth enough to know where the checksums are they can bypass even that and at that point the game is fully cracked. Its a simple last GOTCHA moment a developer can have without a big expense of resources to hit those thirsty for pirating a game the second it comes out. Some fun things to youtube for (i cant access youtube atm) look for an earthbound DRM feature that crashes and erases the save file at the endboss of the game. There's a sonic one that has a creepy screen too. These classic games used checksums to see if specific chips are on the cartridge if it was a bootleg or regular cart."
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6roiri | What is GPU path tracing exactly? | Google searches have not really explained it well enough to me were I even understand it. Unless I'm over complicating it, but what I gather is that everything is rendered over and over so it's realistic as to already being there and things interacting with it? But, I'm confused as to isn't this already happening most of the time? A big thing they're talking about is lighting, but a lot of games I see now already do this? I don't know if I can post youtube links but there is a quake 2 example using GPU path tracing on youtube. | Technology | explainlikeimfive | {
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"Normally a GPU is used to \"rasterize\" an image. In this way, it projects 3d shapes into 2d space with affine transforms. Shaders can be applied to the projected shapes to simulate the effects of lighting on each pixel. Multiple passes layer effects ontop of each other to emulate reflections and refractions, and fog. \"path tracing\" or \"ray tracing\" are techniques instead project rays from each pixel out through a lens into the world. When a ray hits something, various reflection, refraction, and lighting rays are bounced off that surface. The colors are then propagated backwards from possible sources and added up to come up with the final color of the pixel. Path tracing is a harder problem to solve, as ray-object collisions are expensive to compute. However, it's an exact solution to the lighting problem. The more rays you bounce around, the more precise the lighting answer becomes. This allows for physically correct reflections, refractions, volumetric lighting and fog, global illumination, subsurface scattering, etc.. It doesn't rely on any multi-pass process to render different materials. It also doesn't rely on \"hacks\"/\"tricks\"/\"cheats\" to get the effects (eg. shadow mapping, screen-space buzzword, cube-map reflections, etc.). Doing path tracing on a GPU just means using facilities like compute-shaders or CUDA to gain computational acceleration from the GPU."
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6rpga3 | How award shows have footage of a live event that hasn't happened yet | Technology | explainlikeimfive | {
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"They rehearse for live shows before they do them. Most of those clips are from those rehearsals, or previous events that the artists performed in."
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6rpl6v | Would a cell phone work in space? | I understand that temperatures in space would most likely never be ideal for phone use, they are too extreme on either end of the spectrum. I also understand that a phone would never get reception in space. However, if space did happen to be an ideal temperature, could a phone be used to take pictures and perform other tasks if it was in a vacuum environment? | Technology | explainlikeimfive | {
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"The main problem would be heat. Cell phones passively cool themselves via the air, but there's a distinct lack of air in space, so despite the near 0C temperatures in space, without a way to get rid of heat (apart from blackbody radiation), the phone would overheat. If you could cool it, then it should function.",
"If the question is \"would I be able to whip out my phone to take a quick space selfie and send it over Snapchat while in orbit?\", the answer is unequivocally no. At least the part about actually *sending* the Snapchat to your friends, anyway. If the question is \"can I use it to play games when I get bored or for any other offline function?\" The answer is eeeeeehhhhhh... it doesn't look good. Like has already been mentioned, temperature is going to be your biggest problem. However, if the question is \"can I use my phone as a fancy paperweight in space?\" the answer is still no, because paperweights operate by a mechanism called \"gravity.\" ;)",
"Surrey satellite Technology in the UK collaborated with the University of Surrey and produced strand-1. One of the onboard computers was a Google nexus smartphone. Among other things as a \"get people interested in science\" type activity people were invited to submit videos of them screaming to prove that in space no one can hear you scream. As for the thermal issue: - The smartphone had a program on it that served no function but was quite computationally expensive which heated the phone when required. - As for the hot case I'd assume the body of the spacecraft blocked out (reflected) a lot of solar radiation and then I'd suggest just making sure there's a good conductive path to a greater thermal mass. Then paint the hot stuff black. For the power of a phone it should be possible to keep it cool passively, all be it with some hacking around of the phone casing. Source: URL_0 And I'm a former employee of Surrey Satellites."
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6rq1k6 | why do the effects in older movies (some not even 10 years old yet) seem so cheesy now yet back when the movie was released it seem so real! | Technology | explainlikeimfive | {
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"When we haven't experienced something that much, we pay less attention to the details. If we ate bacon for the first time, we'd get blown away by the taste no matter how it was cooked or where it's from - it's unique, delicious and memorable. After eating it every day for a month, we might develop a preference for how it's cooked (less crispy etc). After eating it for a year, we might start to prefer specific cuts of bacon or bacon from specific farms etc. Movie effects that are 'groundbreaking' at the time won't hold up later because we'll have seen it over and over again in other movies since and we will notice the flaws that couldn't be noticed before. Also, if you watched that effect originally as a kid, you've experienced a lot more life in general and you're more likely to scrutitise what you see in any context.",
"What other people said about seeing it when you're young and not having better effects to compare them to both explain a lot. But also, directors are not dumb. They know when some effects work and when they don't and can distract you from a bad effect when you watch it for the first time, especially when you're caught up in the story and characters. When you watch it again you already know what's going to happen and your eyes might tend to wander from the main action, and you start to notice things. Look at this scene from Citizen Kane, which is like 70 years old. Watch is then read the rest of my comment: URL_0 . My understanding was that this scene was not shot in a giant arena, and indeed on closer inspection it looks like the background seating is a painting or something, and the perspective of the stage curtains looks a little wrong. But if you saw this in a theater it would just work, because your attention is on the guy in the foreground and the people moving around onstage are just convincing enough to make you believe you're actually looking at a stage in a big arena.",
"Think of it like this. There are some old games whose graphics at the time were \"amazingly realistic\" are now so \"bad and old\" that they are painful to look at. Meanwhile, some other games from the same time period are just fine to watch. An example is Goldeneye 64 vs Super Mario 64, both great games from around the same time. Goldeneye is still generally fine, but the looks of the characters is pretty painful. Super Mario 64, you wouldn't even really notice much of an issue. This is because Goldeneye was trying to have as realistic a look as it could at the time, meanwhile Super Mario was designed to have an art style. Neither of these is a bad choice, it's just that what counts as 'realistic' is always getting better and better (meaning that what used to count as realistic looks worse and worse), meanwhile an art style is always just an art style. It is today what it was back then. Sure, if you remade Super Mario 64 in the modern age, you could make it look astounding and put the old version to shame...but since nobody really does that (HD release exceptions notwithstanding), the ongoing advancement of graphics quality is not as stark for them. Movies are much the same with their effects. In this case, things can be drawn to 'the little details'. As our technology gets better, the special effects EITHER get cleaner (less random tiny details) or they get more complex (specifically chosen tiny details) but that complexity is designed to help focus you on the correct part of the screen. In either case, this draws attention to the tiny details of older effects that detract from that cleanliness or perfect chaos.",
"Audience expectations. Bear in mind, though, that movies are really intended to be seen once: the idea of having your own personal copy and watching it several times is relatively new, and not what movies were designed for. You wouldn't necessarily notice the imperfections, especially if you were distracted by the novelty of the effect. If you were alive 100 years ago and watching a silent comedy in which bizarre things happen, you'd be too surprised by the bizarre things to notice much else. A man suddenly explodes, leaving nothing but a pile of clothes: you're too busy thinking, \"Wait -- what just happened?\" to notice the jump cut. But for us these days, that's pretty mundane: if you're used to watching all the various *Star Trek* series, movies and spin-offs, the idea of people suddenly disappearing is quite normal. Watch that old black-and-white movie now, and the effect is so unsurprising that you're more likely to notice the flaws.",
"Some movie vfx look dated because of the way they were converted to consumer viewing formats. The fx of movies filmed on 35mm film or even high resolution digital would still look amazing and real - if you watched them at the movie theater. But when converting to consumer HD (up to 1080) digital media - the \"fake\" parts respond differently to the encoding process - producing a ghosting artifact around the cgi parts - making for a slightly different result between the \"real\" shot and the added fx. Enough to make the effects noticeably stand out of their surroundings. The newer 4k digital format changes this - i've only seen a few movies in both 4k and older formats - but it looks like the problem is much reduced or even goes away entirely. There are other reasons of course - but this in my experience is the major one. If you could find a 4k version of the 10 years old movie you were watching - most likely the vfx would look much closer to the theater experience (i.e. - realistic)."
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6rrwiz | Why do we call them drones and not "fancy RC helicoptors"? | Technology | explainlikeimfive | {
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"Some drones today have semiautonomous features that can help them fly back to the point of departure in the event of signal loss or a low battery state. RC copters have a tail rotor, and no autonomous features, and are generally piloted by people that know what they're doing, not just some asshole with money to burn.",
"Pretty sure this was for marketing by manufacturers as RC helicopters (one or two fixed blades) were on the market for a long time, and they needed something 'new' instead of calling them octocopters or the sort",
"They were called quadcopters for several years. The media started calling them drones because that sounds scary.",
"An RC helicopter is controlled entirely by the user, just like a regular helicopter. If you take your hands off the remote, it's going to go down in an uncontrolled crash. Quadrocopters however use a bunch of guidance systems that function independent of the user. They have a whole bunch of on board sensors which are connected to a controller, which keeps the drone stable in the air without requiring any additional user input. If you take your hands off the controls, most drones will autonomously come to a halt, and then either hover at that spot or go down in controlled descent. Some drones even have autopilot features which allow them to move without any user input. If you put the same kind of features into a regular RC-helicopter, or plane, it'd also be a drone."
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6rwfuk | How does nightvision work? | Technology | explainlikeimfive | {
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"Night vision goggles? They pick up infrared and convert it to visible light."
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6rxgbw | How does using my car's airconditioning or other features affect my fuel consumption? | Technology | explainlikeimfive | {
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"Your air conditioning is generally powered directly from the engine using a auxiliary belt/serpentine. When the air con pump is active it will put an extra load on the engine causing both a drop in engine power(relative to the wheels) and an increase in fuel consumption.",
"Using things like the air conditioning or your stereo in your house takes energy, electricity in this case. That energy comes from a power generation plant. The more you use the more the power plant has to work. You pay for that work with a higher electric bill at the end of the month. The air conditioning or your stereo in your car takes energy too. With a car the energy comes from the engine. The more you use the more the engine has to work so the more fuel it will burn. Now with a car the activity that requires the most energy by far is moving the car. An air conditioner takes a lot of energy so it might reduce your fuel economy by 1 or 2 miles per gallon. Using other features like the stereo or GPS don't take very much energy so won't have a noticeable effect on fuel consumption."
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6ry89e | Regarding Bitcoin, what is the importance of a computer solving equations? | I understand that there are people with very powerful computers solving equations for Bitcoin and that they get money for this. 1. Why do these equations need to be solved? Does it secure the entire currency from being hacked? 2. From what I understand, you don't get money for every equation solved, but you will only randomly get paid for solving equation. So this means the more equations you solve the higher chance you get paid? 3. Finally, are these simple equations, or are they difficult? Do the equations get progressively harder? | Technology | explainlikeimfive | {
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"Bitcoin has a proof-of-work system that involves running the SHA-256 algorithm over and over until you get a result with the desired number of leading zeroes. This is done as a way to limit the generation of new blocks. In previous times most currency was based on a fixed amount of gold or silver. Bitcoin uses the scarcity of computing resources to limit how fast new currency is created. As computers get faster, the computing problem automatically gets harder to the point where a new block is generated approximately every 10 minutes which rewards the finder with 12.5 bitcoins.",
"**The reason gold is valuable is that it is a token for a standard amount of human work. Bitcoin is the same but accounts for computational work. ** Why is gold valuable? Fool's gold is just as shiny. Titanium didn't tarnish. Gold is hard to forge and hard to find. A country with a lot of gold has a lot of resources to spend mining gold. Gold represents labor + technology. It has a fixed value. You can accumulate gold two ways: you can work to mine it, or you can work to buy it from someone who mined it. Since you could always go mine it, it sort of has a built in floor of economic value. Bitcoin are the same but instead of digging in the dirt, they factor large prime numbers. This is a well established hard thing for computers (or people) to do. It is the same kind of operation that makes cryptography work so if someone were really good at it (like a Bitcoin alchemist) they would have a large opportunuty cost in mining tons of coins instead of just breaking all the passwords in the world. It's unlikely for that to happen. Since computation is valuable, there is an inherent value in buying something that requires a resource (computer time) be spent on it. It feels pretty perverse but it is just like the gold standard (or [rai stones]( URL_0 ) if you're feeling curious for more weird facts about money)."
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6ryku7 | Balancing characters in a fighting video game. | I know nothing about programming or game theory, but I sure as hell love to play fighting games. (*cough-cough* MORTAL KOMBAAAT!) I understand that balancing means making the fight fair for all characters, but what goes into that when each character has their own styles, special moves, etc? | Technology | explainlikeimfive | {
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"*One* way to do it is to balance the average DPS (damage per second) across all their moves for every character. Some characters might have stronger kicks or faster punches, but if you take all their moves and take the average DPS and make sure it's the same for each character, it'll be pretty balanced. Of course, most games are a little more complicated than that. When you introduce characters with specific styles of fighting (like, one might be really good for juggling, another for counters etc.) you really need to focus more on play testing. There's only so much you can predict with math and code. A *lot* of testing goes into these games. Combos (not the pre-defined ones, I mean stringing moves together) depend heavily on animation timings and invincibility frames, so abusing juggling and stun-locking can often only be found while playing. In fact, I'd wager that a significant portion of development time for these games, goes into ensuring fairness. Play testing and adjusting code is basically trial-and-error, but tweaking little variables is often enough to make a game fair.",
"In game balance, every game has certain \"handles\" that they can adjust and wiggle around until everything feels right. The idea of handles for game balance is pretty common in game design and what they are for each game affects how they balance them. Here's what the most common ones are in a fighting game: - Hitbox: the area of the screen taken up where a move will damage an opponent, these can be resized/reshaped to balance the game - Hurtbox: the area of a character that will cause damage to be taken if hit by an opponents move hitbox. Making this bigger/smaller affects how tanky the character feels. [Hitbox/hurtbox picture]( URL_0 ) - HP: Hopefully obvious. - Move damage: Hopefully also obvious - Move frames: Each move has a specific amount of frames of \"windup,\" where there's animation before the move can do damage, then there's active frames where the move can deal damage, and recovery, which is time between when the move stops being able to do damage and when a new move can be input. Each are adjustable seperately. So you'll typically see move that have low windup and recovery tend to have lower damage, and heavy moves will have longer delays before and after the move. - Block/stagger/counter frame advantage: Most games will have a stagger state when a character is hit by a move, which prevents the character being hit from inputting moves for a specific amount of frames. These will be adjusted against move recovery so that many moves will give the attacking player an advantage on hit, but a frame disadvantage if it's blocked. They're usually adjusted so that light attacks are safer than heavies when blocked, and light attacks will give frame advantage on hit to allow them to make a combo. Frame advantage is a huge deal. If a character has a big advantage on all of their moves, they will be unfair to play against and it can lead to things like infinite combos. - Buffer and input leniency: Different games handle this differently, but sometimes you will see games that use cancelling to set up combos will have a specific number of frames that the next input is allowed on. The length of time that you have to put in the next command can be adjusted to make those heavy damage combos harder to pull off. - Invincibility frames: For games with specials that cause the player to be invincible, the length of that invincibility can be adjusted. - Move variety: A character can be made stronger/weaker by adjusting how all-purpose their moveset is. For instance, a character where all their moves have low hit boxes will struggle against a jumping opponent, whereas a character with move hitboxes that are both high and low will find it much easier. There's a lot of handles to adjust for balance, which is nice, but fighting games are still notoriously difficult to make. It's pretty problematic when all of your adjustments have to be in whole numbers. A move that is too strong with a 4 frame recovery might be too weak with a 5 frame recovery, and you can't simply pick a number in between."
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6rzr5d | How is it that NASA can stay in contact with ships that are hundreds of millions of miles away, but phone companies have such limited ranges of coverage? | Technology | explainlikeimfive | {
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"1. Communication with these spacecraft is done through the NASA Deep Space Network (DSN). It consists of three facilities around the world to give complete antenna coverage in all directions. The antennas are huge and rely on extremely sophisticated and sensitive equipment that goes far beyond the capability of cellphone tower antennas. 2. Spacecraft intended for deep space have a low-gain (LGA) and high-gain antenna (HGA). The LGA broadcasts and receives a wide-angle signal whereas the HGA is highly focused. You can think of it like a flashlight versus a laser beam. By narrowing the beam you concentrate the total power into a smaller area. Cellphone antennas however are omnidirectional like a lightbulb so they waste power during transmission and are poor at receiving signals compared to directional antennas. As an aside, it's one of those marvels of technology that Voyager I is over *20 billion km* away from Earth but still accurately points its HGA at us. 3. Space is big and empty. There are almost no physical objects to get in the way of signals, unlike on Earth with hills and buildings. Importantly there are also few sources of electromagnetic interference. Interplanetary signals are very weak but there is little \"background noise\" to drown them out. 4. The data rate is only partly responsible for the ability to communicate at such long distances. Cassini is in orbit of Saturn over 1 billion km away and had a final high-rate transmission of about 14kbps. While low for modern standards, 14kbps is higher than the data rate of the first-generation digital cellphones. Voyager 1 on the other hand is so far away it can only transmit at 120bps.",
"Im not an expert but I can point out that they aren't the same types of data. NASA is basically sending text and images and the time it takes to transmit doesn't matter. Phone companies are in the business of transferring instantaneous high quality audio. They are two different problems with different acceptable solutions.",
"If you build a radio tower, there's nothing between that radio tower and space except air and maybe some clouds. But that same radio tower might have mountains and buildings between it and a cell phone user. Earth is covered in physical blobs of matter which interfere with radio signals. The sky, however, is not.",
"NASA doesn't have to deal with maintaining many connections at the same time. They also don't have to deal with the kind of interferences that exist on Earth. And, as /u/PoopyPooperman points out, they are dealing with different sorts of data.",
"NASA uses antennas [like this]( URL_0 ) (that little thing on the left side is someone's truck and a motorhome or trailer) for long distance communication.",
"They both use radio waves, just not in the same way. I see that most of the answers you are getting are talking about interference. Interference isn't really the problem here, the FCC has a band plan that minimizes that. Cell Phones are line of sight communication and use nondirectional antennas. Line of sight is just what it sounds like the cell phones antenna needs to transmit in a direct line to the receiving antenna. The antenna is also very small on a cell phone and in the radio world antenna size and quality are important. Going into your basement or too far in the woods may disrupt the line of sight with your cell phone tower causing loss of signal. With space craft such as the Voyager, a directional antenna is used and line of sight is less of an issue because space is mostly empty. The antenna which is very large can be pointed directly towards Earth and the transmission back to Earth can be made with only a few watts, probably not much stronger the transmission your cell phone makes. The receiving antenna here on Earth is very large as well minimizing reception issues. So if you have two fixed points to transmit and receive radio then with high-quality antennas you can communicate over vast distances. However, if you want portability you must trade in some reliability with the transmission and reception of any radio device."
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6s1022 | what happens to the dashboard when airbags deploy | Technology | explainlikeimfive | {
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"Watch [this video]( URL_0 ) of an airbag deploying in slow motion There are panels over the airbag which have seams to split apart on. When the airbag starts to go, it pushes against these panels which break on the seams and push out of the way so the airbag can deploy. The ones on the passenger side and the pillars will have similar plastics that split apart, but the pattern will obviously be different"
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6s2bme | Why do Facebook pages use videos of still images instead of just a picture? | Technology | explainlikeimfive | {
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"I believe it is because videos get more visibility when shared versus text & pic updates. It is all dependent upon Facebook's algorithm which favors more towards videos."
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6s2prp | How do streaming sites put up high quality episodes before Game of Thrones is even aired? | Technology | explainlikeimfive | {
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"It's been widely reported that Episode 4 leaked a few days ago, it's all over the internet.",
"For usual episodes (this one's different) they record the very first airing, encode that, and upload. With an up to date GPU the encoding can be done in real-time and a fast connection can upload the result in real-time. The effect you're experiencing is because if timezones. Right at this moment it is 7:47pm in California, but it is 10:47pm in NYC. Something that airs at 8-9pm, has not started here, but finished nearly 2 hours ago in NYC. Combine these and the episode is often available for streaming before it officially airs in California."
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6s2wnx | How do our passwords stay protected even though many websites/companies know our login information? | Technology | explainlikeimfive | {
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"Most sites don't store your password, they store a hash of your password A hash is specifically designed to be a one way function so it's easy to take the password and generate the hash and check it against the database, but it is hard to take the hash and determine what password makes it. You should have to try lots and lots of passwords to find one that matches the hash you have Not everywhere hashes your password unfortunately. If you can say you forgot your password and they can provide it to you then they aren't hashing it and you should assume that password will get out sometime",
"If you're using the same login and password everywhere, you're not safe. One site with poor data security gets hacked and all of your accounts are wide open. Set up unique logins and passwords. Do it now."
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6s2wwj | What is the difference between programs and algorithms? | Technology | explainlikeimfive | {
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"An algorithm is just a collection of instructions to do something. But that's pretty abstract, it's not tied to the specific way its done. For example there's a maze solving algorithm that goes like this: \"Whenever you reach an intersection in the maze, take an unmarked path at random if available, then mark it. If no unmarked paths are available, take a path with a single mark at random and give it a second mark. Do not follow any path marked twice.\" This is an algorithm, but its not a program, how you perform it, or how a machine performs it will be different, but you can still all perform it. However if you take that algorithm and you write it up in a programming language, to perform that algorithm on a piece of hardware, on a system that can execute that code, then you have a program. The algorithm is the logic, the program is how its implemented.",
"An algorithm is a procedure to accomplish a single task when written out step by step so that it can be followed exactly the same way every time given a set of parameters. It doesn't have to even be digital. The precedure for tying your shoelaces is technically an algorithm. The procedure for determining the square root of a number is an algorithm. A program is a collection of algorithms written in a machine readable format (e.g. a programming language, that can be compiled down to machine code). Which can do something as simple as print a single letter on a tape drive, or a complicated as processing a string of data from over the internet into a video to be displayed on a monitor.",
"If you needed to wash your hands, I could give you an algorithm of go to a sink, get some soap, lather up, rinse off the soap and dry your hands. A program for washing your hands would be something like: -if you're sitting down at a table, put your hands on your seat and move your seat far enough away from the table to give yourself room to stand up. Then, stand up. - if you're sitting not a table, stand up. - if you're lying down, put your hands on the ground and push yourself up to a sitting position. - if you're sitting on the floor, put your hands on the floor and push yourself forward until you can stand. Then stand up. - if you are not standing, say something that will make the programmer question every decision they've made in their life. - if you are standing, determine fastest route to bathroom. - if you do not know fastest route to bathroom, determine fastest route to leave current room. Etc,etc",
"By some definitions, there isn't a difference, but the way the words are usually used: An algorithm is a method of solving a problem, involving a set of logical/mathematical instructions. A program is a set of computer instructions that a computer can understand and run. A program doesn't have to contain any algorithms. For example, the beginner \"Hello world\" program only displays some words. It doesn't take any input and doesn't solve any problem. If you programmed a basic calculator, it probably wouldn't use anything that a computer scientist would call an \"algorithm\", since all it does is arithmetic. There's no special method to adding 2 + 2; the CPU just adds them. On the other hand, an algorithm doesn't have to be done with a computer program. For example, I could teach you how to sort a deck of cards from least to greatest. Flip through the cards one by one, and every time you see a card that is out of order, keep moving it up in the deck until it's in order. Do this at most 51 times and the deck will be sorted. That's an algorithm. If you wrote a computer program that sorts a virtual deck of cards, then you'd be writing a program that uses an algorithm."
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6s36vz | why does FaceTime audio have better quality compared to normal voice call? | Technology | explainlikeimfive | {
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"Old school phones only use a small range of frequencies that humans can hear. This was originally a technology limitation of traditional phone lines. The range of frequencies was chosen so that you could still make out the words the other person was saying even if it didn't sound crystal clear. Modern phones still only use the small range of frequencies when using the \"voice\" channel. FaceTime doesn't use the voice channel of cell phone transmitters but rather the data channel, so they can use much more bandwidth and that means, if they want, they can use a wider range of frequencies for sending and receiving voice signals. Some carriers allow HD voice which is essentially the same thing as FT, using the data channel instead of the limited voice channel to send and receive calls."
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6s3g2h | What are the most important specs to look for when purchasing a new TV? | Technology | explainlikeimfive | {
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"In my opinion, here is the specs in list of importance: - Reliability. So only get the good brands, don't get some weird unknown brand, or Chinese brand. So, Samsung, LG, Vizio, and i've heard Sony are great (never had an HD Sony TV.) - Resolution. 720p is outdated, and 1080p is super affordable now, like insanely affordable compared to the early 2010's when it was thousands. Even 4K is affordable as hell now! I would just get 1080p for any average joe because it looks great as it is, and what are you going to use 4K for? There's barely any Netflix shows or TV channels in 4K, and it's very demanding for games to output in true 4K. - Screen: LED, LCD, OLED. LCD is considered the worst of all types of screens, but not awful! LED is good, and OLED is really good. It's the best. OLED makes everything more vibrant and colorful. They also burn out faster though, be warned. - Output: HDMI is standard at this point, but if you need some computer or older ports, make sure they're included."
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6s3lsc | How can autonomous cars work without fail if there are still human drivers on the road? | Technology | explainlikeimfive | {
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"They can detect and react to human drivers faster and more accurately than a human driver could. They can't work *without fail* ever, since sometimes things happen that simply couldn't be avoided, such as if you're following all the normal traffic laws and going through an intersection just as a speeding car turns around a corner and T-bones you. *Maybe* you could have swerved out of the way or slammed on the brakes or the gas with the one second of warning you might have, but even that could cause you harm. An autonomous car might even be able to do better! The point isn't to make them work *without fail*, but to make them work *with less failure than human drivers*, which is actually already pretty much the case.",
"Nothing works without fail....But it is rapidly becoming possible for the combination of sensors and computers to manage the necessary tasks to maintain safe vehicular control EVEN with the random behaviors of the world and meaty drivers factored in.",
"By cameras and sensors it maps out the vehicles and pedestrians, stop signs and stoplights, allowing it to know when it has to stop, turn or go. Cars are \"seen\" by the car and can turn, stop or slow down according to speed and emergency."
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6s3xq2 | How do long exposure photos of space yield such an amazing image? | What exactly is happening during a long exposure of the night sky? Why does it make things and colors you can't really see appear over just a 5 minute long exposure time? | Technology | explainlikeimfive | {
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"Let's say I draw an X on a piece of paper right in front of you. But to do such takes time, and I do it point by point. So I draw a dot. Then another, then another. Every 5 seconds I draw a dot. Now after a minute you may have something that kinda looks like an X on that piece of paper, though kinda vague and hard to see. The longer you let me draw, the more and more the true image I was drawing takes shape. Now replace dots with particles of light, and the paper with a camera lense and sensor, and the X with a distant galaxy. So little light makes it to us due to scattering that these images are drawn pixel by pixel over a vast amount of time compared to looking at something right in front of you."
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6s44e5 | Why do some banks force users to create bad passwords? | For example, one popular bank where I'm from (not mine, thankfully) requires passwords to be exactly 8 characters, no special characters, not case sensitive. Shouldn't banks allow (or force) better passwords than that? Is there an actual reason for this other than bad programming? | Technology | explainlikeimfive | {
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"I'd be extraordinarily suspicious of that bank. Believe it or not, the Bank's password security might WORSE than you think. The likely reason is that the passwords are being stored in regular sized chunks. So if you have a space 64 characters long, you would know that there are 8 passwords, and character 8 is the start of the second password. So it takes much less space and can be checked really quickly. Thing is, NOBODY SHOULD **EVER** DO THIS! A password should be stored after it's been put through a mathematical function called a hash function, and with bits added to it so that it's a standard length called a salt. That way if someone ever steals the list of passwords, it's functionally impossible to get back the original password. The math works out so that you can quickly turn a password into a series of numbers, you can check if two numbers were made from the same password, but it's really really hard to turn the numbers back into a password. By storing it like that, you made the entire list extremely vulnerable, any IT tech with access can see everyone's passwords.",
"100% bad programming, no reason for it, it is actually worse than you imagine. Any good web service like Reddit stores passwords in a rather interesting way. Well, rather, they do not store the password. Let me explain. Good services will not store people’s password, they will store what is known as the hash of a password. A hash can kinda be described as a fingerprint of a set of data, a hash is a relatively short number that is created after running a set of data through a hashing algorithm. Ideally, you cannot reverse this operation, you cannot generate a set of data to satisfy a certain hash, but every time you run the same data through the hashing algorithm, it produces the same hash. For example, the SHA256 hash of “password” is 5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8. Now, you can go to any SHA256 calculator online and input “password” and it will give you that hash. But if you didn’t know that data I used to make the hash, you cannot find it without just trying every possible data. So, for security purposes, logging into Reddit for example involves you sending Reddit your password, them hashing it, and checking if that hash is in their database. This is all done so that in case the database is leaked, no passwords are leaked. After verifying that you are who you say you are, the password is deleted from memory. Now, the thing is that there are no restrictions on which alphanumerical/symbol characters you can input to the hashing algorithm, it will make a hash for all of them. It also doesn’t matter how long the data is, it could be a password that takes up gigabytes, it will still make a hash 64 characters long like above. This means that the bank is likely storing the passwords in a file that doesn’t support certain things, and this is bad, very bad, if the database is leaked, there goes all your money. There is no reason to have such a restriction with hashes password database security. DO NOT USE THIS BANK"
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6s66b2 | How does turning the knob on my radio let me hear different things? | Technology | explainlikeimfive | {
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"Radio works by superimposing a signal onto a carrier wave. These days, that's usually done using _frequency modulation_, or FM. In other words, the encoding process alters the frequency of the carrier wave in order to store information. Before FM, there was AM, amplitude modulation, where the amplitude (the up-down axis of the wave) was altered to encode the information. So, your radio actually receives all the signals being put out by transmitters. What you're doing when you turn the dial is alter a filter that is decoding the signal off the carrier wave - you're just choosing a specific slice of signal to be output to the speaker."
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6s6f7s | How did Pixar create such amazing CGI (i.e. Toy Story, A Bug's Life) with early 90's technology? | Technology | explainlikeimfive | {
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"Much of the software required had to be made from very elementary work into 3D modelling things that we now take for granted, like polygons and UV coordinates (systems for applying 2d textures to 3d objects). In the earliest days, like with the short Luxo Jr., polygon coordinates had to be manually plotted and programmed by calculating and then writing down the XYZ coordinates of each point for each polygon, before animation work could take place. Pixar's software developed similar but different tech to the animation and modelling techniques used in early 3D video games, but with more sophisticated rendering and motion controls. You can really see the level of detail increase over time when you watch their movies in chronological release date order. * Toy Story - ambitious tech demo with extremely well done plot and characters * A Bug's Life - Lighting and scene detail density improvements, with grass, plants, and large crowds * Toy Story 2 - Texture and rendering improvements for human characters * Monsters Inc. - Fur and environments * The Incredibles - Lots of everything, but most importantly clothes and cloth simulation * Cars - Lighting and rendering improvements * Ratatouille - Rendering improvements for human characters and organic matter like food * WALL-E - Lighting and procedural generation (like trash and robots * Up - Lighting and color effects and it goes on.",
"Two observations. First, yes, the state of computer graphics in 1995 was not nearly so advanced as today. But it wasn't as bad as all that. Ray tracing had been around for more than a decade at that point. Pixar had actually used RenderMan--its proprietary software responsible for much of the heavy lifting in the *Toy Story* animation process--in films as early as 1991's *Beauty and the Beast* (Remember the ballroom scene? Yeah. That.). Then, as now, *cost* is as much an issue in the realism of computer graphics as technical ability. Sure, today's technology lets us achieve a higher degree of realism than we could in the 1990s for the same price. But even back in 1995, you would probably have been surprised at the degree of realism possible with CG given enough budget. Most people were. Second, it's undeniable that Pixar significantly advanced the state of CG technology in the course of producing *Toy Story*. Motion blur and texture mapping in particular got a lot of attention. So the answer, in part, is that they simply made new technology as they went.",
"CGI movies are not bound by the need to be rendered in real time. Video games need to be rendered at 30-60fps in real time in order to appear fluid and responsive. But with movies, you can quite literally render one frame every 12 hours, and then play back the final render at 24 fps. Basically, you can get terrific graphics with old tech, as long as you are willing to wait months for it to finish rendering.",
"To add on: Earlier on, they also purposely picked objects with a focus on \"plastic-y\" textures that worked well in early CGI and minimized other objects. For example, their first two movies focused on toys (with some humans but screen time minimized) and bugs mostly with hard shells. And even the humans that do get screen time, things were focused on keeping them simple. E.g. Andy and Sid both have conveniently buzzcut hair.",
"Another point The human animation in Toy Story left much to be desired, reflective of the technology at that time. By using toys and bugs, Pixar could get around that problem, because your brain isn't expecting realism from toys and bugs"
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6s9io7 | How are sleep tracking devices (smartwatches or wristbands) able to analyze your sleep data so accurately? | Technology | explainlikeimfive | {
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"If they weren't accurate, how would you know?"
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"url"
] | [
"url"
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|
6s9nwo | Why is hotel internet/cell service always so terrible. | I travel a lot for work and end up in hotels pretty frequently. But no matter what kind of hotel I end up, 9/10 times the internet is just awful, and not just slow but it will just DROP every few minutes. If I’m on my phone and not on wifi, that’s usually degraded to 3G/4G and not LTE. I just did a speed test on my phone and 1mbs down on cellular and .625mbs down on wifi. Why is this, and is there any way to make it better? | Technology | explainlikeimfive | {
"a_id": [
"dlb6wen"
],
"text": [
"Lots of people concentrated in a small area all trying to use the same resources at the same time. Want fast hotel internet? Try it at 10 am on a weekday (if there are no conferences going on). Some hotels also now cap basic service and want you to pay for faster access. So they have \"free\" internet but it's only about 2-3mb/s. Ditto for cell phones. A few hundred people in your hotel all trying to use the same cell sites to get better internet than the shitty hotel wifi."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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