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nxh9kl | When a game's "code is lost" what stops a company from dumping/decompiling code from a disk or cartridge copy of the game for things like remakes and remasters? | Technology | explainlikeimfive | {
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"Decompiling isn’t all that easy, and if it works at all you’re left with bare code that contains no notes about how anything is supposed to work. Millions of lines of code that someone wrote years ago with no explanation about what they do or why. While it’s theoretically possible to reverse engineer a program that way, it is much too time consuming to be practical for a product you’re trying to make money on.",
"They absolutely can. However 99/100 times it's a pain in the neck and more effort than rewriting the thing from scratch. Code is written by humans for humans. It has nice human structures that make sense, it is organized in to well named files in neat logical folders, it has descriptive variable names, it hopefully has a bunch of comments so that developers can communicate with both each other and their future selves, functions have clear markings what they are intended to do, all that nice stuff. The computer doesn't care: it neither needs, understands, nor wants any of that. In the process of compiling the code from human-code to machine-code the compiler will discard anything that it believes isn't useful to the final product. Comments are thrown out, file structures pressed to single files, variable names replaced with shorter pointers, all of the human element vanishes. Decompilers can't bring any of that back. They don't know what the compiler threw away and have no way of recreating it. What it will do is create its best approximation of \"human-readable\" code that does the same thing as the original code. However it will still have all of that awkward computer-preferred structure and meaningless variable and function names. Working with the de-compiled code as a human is extremely tedious and you'll need to put in a lot of work just understanding what each section of the code is meant to be doing. And remember we're talking hundreds of thousands of lines of code: Libraries worth of nonsense. At some point it's better just to give up and do it again from scratch.",
"Software developer here, former game developer (not that it matters), Compilation is a one-way transform. Take, for example: bool less_than_seven(int x) { return x < 7; } This is code, a text document written for humans, by humans, and only incidentally for computers to possibly compile and execute. Computers don't need to know what a `bool` data type is, it doesn't need to know that this is a function, and specifically, it doesn't need to know that it's named `less_than_seven`. It doesn't need to know the variable is called `x`. It probably doesn't even need the variable. It very likely doesn't care that we're doing a ` < ` comparison. All this information can and likely will be lost when translating to machine instructions. You can't search an executable program for `less_than_seven`. That information is gone. This code, this function, very likely won't even generate machine instructions for a function call - the compiler might determine the cost of pushing and popping the call stack is more expensive than just performing the comparison in-place where this code is used elsewhere in the source. In place of a variable stored in memory, the compiler will probably store the value in a register. The compiler might even deduce that there are more clever tricks, faster instructions to use than the built-in less-than compare instruction; the program will produce the same result, but it won't be intuitive. So gone is all the context - function names, variable names, variables, and data types; gone is the intent as it was expressed for humans in the source code. There are tools to decompile executable code, but it's tricky at best for other technical reasons. And of course, the tools don't know what it's decompiling. So how does it know that some particular piece of memory stores hit points, or bullet counts? All the tool is going to do is deduce what might probably be a variable, and call it `variable_1234_`, and that's all you're going to get. And typically, these tools CANNOT produce reversible code - that is to say, what they generate won't compile again back into the same binary from which it was deduced. The best you can do is reverse-engineer an approximation of what the original source code might have been. And I emphasize *approximation*, because it won't be exact, and it won't be correct, and it won't be a faithful reproduction. It is incredibly challenging.",
"With all the optimizations and obfuscations done by modern compilers, the process of compiling software is generally a one-way trip. When you lose a game's source code, you don't just lose the thing that makes the engine work: you often also lose the most important source of documentation and insight as to how it was intended to work. Automated \"decompilers\" exist, but they can't actually reproduce the original source code: they can port the machine code to a higher-level language, but this generally bears very little resemblance to the original source. That's not to say that it's useless -it can be an important reference tool as you rewrite the program- but in the end you're still rewriting the program from scratch."
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nxilgt | Why can screens only be viewed from certain angles when wearing sunglasses? | I have noticed for a while that when wearing my sunglasses in the grocery store the screens of the self checkout appear to be off/black when I approach them from the side and I can only see what's on the screen when I'm in front of it. Today I was on the bus playing a game on my phone and the game plays horizontally. I stared at it forever thinking the phone screen was turned off until I realized I could only see the screen when it was vertical. So, why does the light only pass through my sunglasses from the "correct" angle? | Technology | explainlikeimfive | {
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"your sunglasses are probably polarized because it helps against glare from the sun. LCD screens also contain a polarizing filter to make sure only the color of light you're supposed to see comes out (if you take it apart the whole screen turns white) the two interfere with each other",
"Line waves can have different orientations. This is known as polarity. Sunglasses reduce the amount of light hitting your high by blocking light base on polarity. Imagine, for example, that light could be \"up-and-down\" oriented or \"left-and-right\" oriented, at random. Your sunglasses have filters which only let \"up-and-down\" light through and block \"left-and-right\" oriented light, thus blocking 50% of the light hitting your eye. Computer screens can emit light only of a single orientation. So when you, for example, turn your phone, you are turning the orientation of the light it is emitting to light that your sunglasses block."
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nxonio | How exactly are emails sent, like the actual process of the data getting sent to another device that’s for example on another continent? | Technology | explainlikeimfive | {
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"There are a bunch of standard communications protocols that make up what we call \"The internet,\" like **H**yper**t**ext **T**ransfer **P**rotocol (http) which transfers webpages from their server to your device. When you send an email, your computer converts the text and the relevant formatting information into a message, which it transmits to the recipient's mail server using a protocol called Simple Mail Transfer Protocol (SMTP.) When a user \"checks their email,\" they download messages from the mail server using one of two protocols - Internet Message Access Protocol (IMAP) or Post Office Protocol Version 3 (POP3.) Essentially the process is - you compose an email, SMTP sends it to the recipient's mail server. Recipient downloads the email from the server using IMAP or POP3.",
"Hi :-) How Eli5 would you like it? ;-) - E-Mails aren't getting sent from your outbox to someone's inbox, - but rather over your internet provider's connection - to your email service, - over their internet through different connections across the globe, - to the recipient's server... - Where it waits to be downloaded (Either until they check or sending out a \"Hey, you have new mail\" to their client). & nbsp; Let's say your mailbox is mysupergreatmailbox444 at URL_0 . and you send a message to Germany, e.g. ilovetogetmailsfromoverseas222 at URL_1 . - You write the E-Mail and hit send. - If you use an email client, there will be settings like server, port, account password, and so on. - Internet & Computers doesn't work with names like \"Hotmail\" or \"GMX\", but with IP addresses (numbers like 123.222.127.333 or a more modern format). - Your computer asks your internet provider or other \"DNS\" (Domain name service, basically a phone book) what IP address (a number) URL_0 has. - Then your e-Mail client will connect to that server's number with your log-in data, trying to establish a connection. (If you write an email on your email provider's site, that step basically gets skipped. You instead log in to the website and save the email there directly.) - Hotmail then saves your mail to your account's outbox, sends it to the receiver. If it fails it will retry a couple of times. - Similar process. Hotmail asks a DNS what IP-Address URL_1 has. Then tries to send the data over the internet tubes to that server's IP. - Each transfer is made up from different little pieces of information, and gets collected at the other end. So your eMail might get send in little chunks across different routes, servers, across sub sea cables, ground lines, satellite. Imagine you write a 10 page letter and send each page through a random postal service. The recipient sorts them if they arrive out of order. If a page goes missing, the recipient will ask for it again. It's rather chaotic :-) - The recipient's mail client will check their provider's (GMX in the example) server--- - You've guessed it. The E-Mail client will look up GMX's IP address, connect with log-in data. Send and download messages. - The recipient's E-Mail program uses either a protocol like IMAP (TL;DR: Synchronizes new messages with the server and your other devices) or the older POP3 protocol (Basically downloads and deletes). - The E-Mail client will download & display the message. If they use their E-Mail provider's website, they will display the mails as website to look at and thus provide a human interface to the saved E-Mails. Never have the recipient's E-Mail program and yours interacted directly. Not unlike regular mail."
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nxrz1x | VHS won the battle vs Beta. Why? | Technology | explainlikeimfive | {
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"I would be curious if anyone has any source data for what I was always told; someone on the VHS side of things convinced several of the main producers of porn to adopt the VHS format, and from that time betamax was losing the battle one inch at a time."
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nxt9j5 | How come animals can eat raw food and be fine but humans get sick from it? | Technology | explainlikeimfive | {
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"Humans don't get sick from eating raw meat. They get sick from eating raw, *contaminated* meat. We can eat as much raw beef as we want as long as it's healthy and fresh. Most of us just don't like it. Animals don't store food, they eat the kill immediately so it doesn't have time to go bad.",
"It's worth noting that our species may have come about specifically because our predecessors learned to cook food. We simply haven't needed the iron stomachs of some of our relatives.",
"Raw meat, in particular tends to make us sick because we have stored it for a while after it's died, allowing things to grow on it. Predators eat their kill right away. Raw meat is often OK for us if the *outside* where bacteria grows has been seared (see Pittsburg rare steaks or ahi tuna) or if the meat was prepared the same day it died or flash frozen near time of death and thawed near time of consumption (Sushi is one or the other depending on proximity to the ocean.) Scavanger animals like vultures, on the other hand, have developed special resistances to the kinds of bacteria that grow on days old carrion."
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nxwwy1 | In some US States, video recording is legal but audio recording requires 2 party consent. Why are they treated differently? | Technology | explainlikeimfive | {
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"Most of these laws were actually written in regards to wiretapping, as in bugging a phone. Before surveillance cameras or even video cameras ever existed."
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nxyh8z | Why do HDMI cables have such high bandwidth capability when most of the content we watch is usually at a much lower bit rate? | Technology | explainlikeimfive | {
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"Because the data stream you get from YouTube or Netflix is compressed and needs to be processed to create an image. A 1080 TV has 2,073,600 pixels it must draw 60 times a second. Each of those pixels has has 3 color elements that require 10 bits of data to encode for. 2,073,600 pixels * 30 bits (pixel color value) * 60 frames per second = 3,732,480,000 bits/second. Divide that by 1,073,741,824 bits in a gigabit and you get 3.47 gigabits/second required to stream a 1080p video at 60hz",
"Hi :-) The TV doesn't receive high (loss based) compressed video (e.g. not MP4 like you're used to when watching internet videos), and thus video signals need a larger bandwidth. If you attach a blu-ray player, media stick, camera, you don't want to add (more) compression artifacts. Plus there's always overhead, planning ahead for higher resolution standards.",
"To add to what u/schorhr said, the actual data rate for a 60fps 1080p video stream is somewhere around 4 or 5 gigabits per second through an HDMI cable. 60fps 4k is four times that. If you're watching a DVD/Blu-Ray or streaming video, the video source is handling decompression and each frame is sent over the cable as an uncompressed image. If you're playing a video game then the video card in your computer or console is sending each frame uncompressed pretty much as soon as it's done rendering it."
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ny3b79 | How are Virtual Machines made? | Technology | explainlikeimfive | {
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"They reserve part of your hardware and it runs a second OS on that. Running a VM will take away resources from your applications running on the main OS. VMS will allocate the resources, even if they are not needed. Therefor a VM should be configured with minimal resources, especially when running on your personal machine. When running a VM in the cloud there is usually multiple machines that form 1 big machine, which is called the hypervisor. That big machine is then broken down in multiple VMs. These are the ones offered by AWS, GCP or Azure. (Or any other cloud provider) So a cloud VM is run on multiple hard metal machines, when you would shoot one of those hard metal machines with a shotgun, the VM would continue to be online, as the hypervisor continues to live on. When you keep shooting, the hypervisor will eventually die, taking your VM with it."
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ny5tni | Why is the recommended brushing time the same regardless of the type of toothbrush? | My 10 year old basically asked me this when I replaced his manual toothbrush with an electric one, and I had no answer. If a powered toothbrush does more brushes per second than a manual one then shouldn't you have to bush your teeth for less time? Or if 2 minutes is recommended for the electric one then shouldn't you need more time with a manual? | Technology | explainlikeimfive | {
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"One of the useful things that toothpaste usually contains is fluoride, which can fill microscopic holes in your tooth enamel and stop them from growing into larger and more problematic holes. The two minute thing is more about letting the fluoride have time to be in contact with your teeth and do it’s thing, and less about a particular amount of mechanical action from the tooth brush bristles. This is also why mouthwashes say not to eat or drink for a while after using them. They usually contain fluoride as well, and if you don’t eat/drink/ rinse with water after the mouthwash, it leaves some fluoride on your teeth and gives it longer to work.",
"Although the fluoride is important, the conditions necessary for fluoride to do its thing means that it's more important to expose your teeth *often* rather than for a single long time. The recommended 2 minutes is more about making sure that you brush *all* of your teeth for enough time to scrub off the plaque. Consider how you brush: you hit different \"zones\" in your mouth, focusing on a couple teeth at a time. Two minutes of brushing across your whole mouth works out to be only a little bit of brushing on each tooth."
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nyf8jo | How are qbits read and useful? | Technology | explainlikeimfive | {
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"From what I understand, they are both a 1 and a 0 at the same time *until* they are read. At that point, they resolve into either one or the other. But there will be another bit entangled with it, such that once one of the qbits is read, the other is known instantly.",
"n entangled qubits can be in a superposition of all 2^n states. When they are measured you only get 1 state. Quantum Computers use quantum logic gates to manipulate the probabilities of which state is output upon measurement. The goal is to use constructive and destructive interference so that the wrong answer are cancelled out and the right answers are amplified.",
"I'm not the most knowledgeable on quantum computers, so take this with a grain of salt... But Qbits are in both states until read. When read, you only get one answer. As to why it is useful: think if you were solving a problem, with a number of variables. All those variables could change and your outcome could change. In a normal computer, you'd have to calculate every possible combination of variables one at a time to get an answer. In a quantum computer, since everything exists in both states, to oversimplify you can have every combination existing in the same space at once, and you simply need read the outcomes. This can make problems, like brute forcing cryptography, very simple as you can test everything at once and only read the correct output."
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nyf9yu | why 3G is basically useless now? | I've noticed among myself and my friends that the 3G technology doesn't work as well as it used to, or not at all. When I say not at all, i mean if our phones drop from 4G to 3G there will be little to no service available. Phone isn't connected to the interwebs. | Technology | explainlikeimfive | {
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"More physical assets and infrastructures are being adjusted to 4g and 5g now, which leaves very limited resources left to handle 3g signals and data. This slows any 3g applications down immensely to the point of non- function.",
"> or not at all. Verizon turned 3G off completely last year, AT & T is planning to in February of 2022, and T-Mobile will turn off their 3G and Sprint's old 3G around the same time.",
"Can somebody explain ELI5 what 3G, 4G and 5G exactly mean? Are these frequencies? Volume of data?",
"Your phone drops to 3G when there is no 4G reception. So 3G will only be used when the signal is possible to be received correctly but 4G is not. So it is not that 3G is worthless, it is that the phone only uses it automatically when the reception is very bad and 4G do not work. If you instead force your phone to use 3G when there is a good signal it works fine. It is likely a lot faster than it was in the past for you because relatively few used is and there is a limited amount of bandwidth per cell. I have no idea if you can force a iPhone to use 3G but for android it is possible, On my phone, it \"SIM card & mobile data\"/click on one of the two sim cards/\"Preferred network type\" and not you can force it down to 3g/2g or just 2g On my previous phone, it was under \"addition network setting\" in the main setting. Exactly where it depends on the phone. If you do that 3G works fine because you use it when the reception is good. The extra speed with 4G and 5G is not primary to increase the speed to an individual user but to increase the amount of data all users in a single cell share. So the network does not slow down when many use it at the same time. If there only was a single user in a cell the bandwidth is enough for normal phone usage.",
"Fewer towers are providing it and everything is using more data. Even basic webpages run code that is far too advanced for 3g to load quickly/properly.",
"Useless can be subjective. I still use iPhone 4s with 3G and my speeds are 6 megabits per second. Some people call that useless but for many people even in the developed world that is very useful. Whether 3G is being decommissioned or not often depends on the locality. Often regions are designated specific licenses to operate some bands have most use for 3g wheras other bands have more than one mode being used. For example, in many places in Ohio AT & T is authorized a certain chunk of the 800 MHz spectrum depending on the part of the state. My understanding is the way this is authorized in these parts doesn't make it always easier for them to light up 4g on 800 MHz so it's more economical to just keep 3g here consequently 3G is ok in many parts of Ohio. Some frequencies used for 3G are better able to go over obstructions or go through them. As a result, whether a tower gets turned off or not can make a great deal of influence whether your service goes out. It's possible your area was never that great for the used 3g frequencies by your carrier in your locale. So when they turned off a single tower then that ruins your service quality"
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nyh6k4 | What's happening when a charging battery is full, but still keep receiving power ? (Smartphone stay plugged all night for instance) | Technology | explainlikeimfive | {
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"Smartphones have small circuits that turn off the power when the battery is full, even if it’s still plugged in. Overcharging a battery can damage it and possibly cause it to explode. Just being near 100% charge damages it.",
"When a battery hits full, the charger stops charging. This is built into pretty much all batteries/chargers, either by the nature of how the battery works or by a circuit that exists solely to do disconnect the battery when full. If this doesn't happen, then the battery is overcharged and can quickly overheat or even explode.",
"The battery itself stops being charged. Putting more energy in would damage it, or could even start a fire -- it's like putting too much air into a balloon. But, the phone itself needs electricity too. So the charger keeps giving enough electricity so that the battery doesn't have to do any work until you unplug the phone."
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nymhd1 | How do ISPs work? | Technology | explainlikeimfive | {
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"The internet works like roads do. You home connects to smaller roads (your ISP) which in turn connects to major streets (Tier 2 ISPs) which in turn connect to major highways (Tier 1 ISPs). Those major highways connect to one another, creating a large web of roads/streets/highways that connect every house in the country (or in this case, the World Wide Web). You **must** get connected to the web somehow by finding someone to connect you to the larger infrastructure- you have to connect to another ISP at some point. You could bypass your local ISP and connect directly to a Tier 2, but that would require them laying dedicated cable to you home and would likely be cost prohibitive. Long story short, you really can’t get around your ISP. There are different ISP options available (wireless ISPs - or WISPs - are becoming more common) but you’ll need one no matter what you do."
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nynegy | How does a SAM distinguish different targets? | How does the SAM (surface to air missile) not fire on friendly aircraft and only on enemy aircraft? | Technology | explainlikeimfive | {
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"As others have mentioned IFF exists to identify aircraft. But it's also worth pointing out the launcher isnt operating alone, it's linked to a detector, usually radar. This is the eyes, it has a computer brain and the iff coming off the contact is part of the information set that makes decisions. Some missiles then themselves have smaller detector/decision setups and can change their minds after launch All these things together make them pick legitimate threats out and stop them whacking flocks of birds etc etc"
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nyum8j | Why do wall sockets only have 1 or 2 plugs? | I've always wondered why there were only two. Can't we add more? | Technology | explainlikeimfive | {
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"There is typically a code (for safety) regarding electrical wiring. There is always the option of running more wires to more outlets, but there is a limit to how many sockets can be wired for a single pair of wires (by code). Also a outlet boxes are very standard items - they are low cost because they are made in large volumes and made to common specification. Anything custom will be very expensive. More outlets means more circuits, means more wires, larger distribution boxes and more circuit breakers. Lots of things can be done (within the electrical code for homes) but it is a matter of paying a lot more. Most households don't bother with the added expense.",
"Completely normal in Norway to install quadplex (4 plugs) behind Tv/media. 6 plugs, where max 2 can be europlug, are required in areas where tv/media is planned to be installed.",
"Builders usually want to spend the minimum amount on materials and labor to make a saleable house. If they could include even fewer outlets, they would. If they could have rooms without heaters, they would. But the electrical codes and building codes stipulate a minimum, and that's what gets built. I use the 2- > 6 outlet expanders basically everywhere. There is no harm in that.",
"4 plug outlets are a thing I have plenty like that. Google “double gang” or “double duplex” outlet.",
"Technology connections did a great video explaining why breakers protect the wires in the walls. If we had more outlets then we'd need more dedicated wires and thus more breakers. It is pretty full as it is. URL_0",
"Houses built long ago (say 30s) had one plug per room. Modern homes have a duplex plug every 12’ of wall or closer (many devices come with 6’ cords). I have changed 6 of my duplex plugs out for quadplex due to all the chargers, etc.",
"Yes, we can add more. My wife sells new houses and those things have tons of electrical plugs. However, what if your house was built 50 years ago? How many things were you going to plug in *back then*? In your living room you probably had a television, and maybe record player or radio. And... what else? You could have a few lamps as well, but those probably wouldn't sit right next to your TV. Today we have a lot more stuff that uses electricity, that we expect to use at the same time. But houses even 30 years ago might just expect to have a TV and VCR on the same outlet. If you wanted to add a Nintendo or something you could use a power strip."
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nyweh0 | What is an “amp” link? | Posted a link to clarify an AMA and was asked not to post “amp” link. Please explain. Much appreciated! | Technology | explainlikeimfive | {
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"What is AMP? AMP is an open-source web component framework developed by the AMP Open Source Project, first announced by Google in 2015 as a reaction to Facebook’s Instant Articles and Apple News. While it was originally aimed at accelerating mobile pages (hence AMP), it’s now a much broader project aimed at improving the UX of websites, stories, ads and mail. The AMP framework consists of three components: AMP HTML, which is standard HTML markup with web components; AMP JavaScript, which manages resource loading; and AMP caches, which serves and validates AMP pages. In plain English: AMP is Google’s attempt at making pages (and more) faster. They did a good job, pages built with the AMP framework will normally load faster. However, as this article explains, you won’t notice much of a difference unless the AMP library is served using the AMP cache, but more on that later. You can read more here: URL_0"
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nyx2ev | How are certain songs recorded so that some sounds can only be heard through one earphone and not the other? | Technology | explainlikeimfive | {
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"Most songs are recorded with all the instruments separated. Each instrument records a separate track and someone mixes them together later. Stereo formats have the left and right separate so the can adjust what sounds come into each ear.",
"When you listen in stereo you're actually listening to two different tracks in mono - one in each ear.",
"A stereo recording is two entirely separate tracks. Theoretically, one could be a hummingbird drinking nectar and one could be a Concord at 104% of maximum thrust. Basically, if the mixer wants you to hear a sound in one ear only, they put it on one track and not the other. One method of recording stereo is to have a model of a head and a microphone in each ear, so you can capture the sound exactly as a person would hear it. But that's not the only way. Art, ya know)"
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nyxmhk | How were game cartridges copied back in the NES and Atari days? | After the main game is made, how are the backup copies of the game manufactured, back when computers weren't as common as it is now. | Technology | explainlikeimfive | {
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"A normal user wouldn't make a copy of it. As for manufacturing them, I believe most of them were masked ROM, so the contents would be built into the chip as it was manufactured. You couldn't erase them and put something else on them. There were EPROM and EEPROM chips that you can write to after manufacture, but you'd need a purpose built programmer to read the cartridge and write the copy. I expect anyone selling such a device commercially would have been sued for enabling piracy."
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nyy4og | Why is it so difficult for software to give an accurate amount of time remaining for an install? Isn’t the install process relatively discrete? | Technology | explainlikeimfive | {
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"There are always other programs running on your system. If some of them decide to use memory or the drive right now, your install can be delayed for an unpredictable amount of time.",
"Your assumption is that internet speed and hardware speed stays the same throughout the entire install process. You need to consider the fact that these speeds constantly change and can change several times within a second. Having a perfect countdown will rarely be the case if at all."
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nz6350 | Why do radio stations have acronyms before the number? | Technology | explainlikeimfive | {
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"In the US all broadcasters are assigned a series of call letters as an identifier when they get their license from the FCC.",
"That's a call sign. It's a unique alphanumeric code that identifies all radio and television broadcasters. In the US such things are regulated by the FCC. Stations east of the Mississippi start with W and stations to the west start with K. A station can request a specific call sign as long as it's unique, but otherwise they are assigned randomly or sequentially."
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nz7hn8 | How do lock companies produce so many unique lock key combinations through a standardized production methods? | Technology | explainlikeimfive | {
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"The unique combinations for a lock depend on the number of pins in the lock and the number of possible positions. When the key is inserted it pushes up on the pins based on the shape of the key, and based on how high the pins are pushed it can unlock the door. So if you have 7 pins, with 5 different possible heights each that's 7 ^ 5 = 16,807 possible combinations. They make a fair number of duplicates as well, so your specific lock combination might get made a whole bunch of times. But distribute it coast to coast and the chances of your key working in any other lock in your neighborhood or town is slim to nil. Different lock types also use different shapes of keys, so your key won't fit into a different brand or type of lock. If you're worried about the chances of your door key being duplicated, don't be. To be perfectly frank if someone is sufficiently motivated it's much easier to sledgehammer down a door or break a window than copy a key or pick a lock... There are much easier ways to break into your house than copying a key, get an alarm instead."
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nz9orz | During a shuttle launch, what happens at T-6.6 seconds vs. what happens at 0 seconds? | At T-6.6 seconds, you see a huge fireball come out of the rockets, but the shuttle doesn’t actually lift off until 0 seconds. What happens at 0 seconds that isn’t happening at T-6.6 seconds? I think I found a Wikipedia article, but it’s way over my head. | Technology | explainlikeimfive | {
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"At T-6.6s they begin firing up the three Space Shuttle Main Engines underneath the Orbiter. These are liquid-fueled engines that pull fuel from the big orange External Tank. The SSMEs are *extremely* mechanically complex and things could go very wrong very quickly if an engine fails during launch, so NASA lets them run for a few seconds to make sure they’re working properly. Once the SSMEs have stabilized, the two Solid Rocket Boosters strapped to the side of the tank are ignited and the Shuttle lifts off. Unlike the liquid-fuel engines, there’s no way to shut the SRBs down after they’re lit, so they wait until the last possible second.",
"They stagger start the liquid engines (to limit stress), as the engines come up to full power. As they start the main engines, the thrust has rocked the shuttle forward. When it rocks back into the original position, they start the solid fuel engines. This is timed perfectly to account for the slight rocking. Anytime before they light the solid fuel booster, they can shut down the main engines and abort the flight. Once the solid fuel engines are ignited there is no turning back, it's going to fly.",
"In addition to what people have here's the actual countdown starting at 6 hours: [ URL_1 ]( URL_1 ) Here's the site with pretty much everything you'd need to learn to be an astronaut and fly the shuttle (training materials, cue cards, etc). It's amazing that all of this is now online: [ URL_0 ]( URL_0 )",
"At T-6.6 seconds, the 3 main engines on the shuttle ignite, one at a time staggered by 120 milliseconds. It takes a few seconds for the engines to spool up to full thrust, and the control computers check to make sure each engine is at the correct thrust and all other sensors are nominal. Assuming that's the case, at T-0, simultaneously, the SRBs are ignited and the bolts that hold the shuttle down the launchpad are released and the shuttle lifts off. The 3 main engines are ignited first because they can be shut down if something is wrong, but once the SRBs are lit, there's no way to turn them off, so they make sure the 3 main engines are burning normally before igniting the SRBs and committing to liftoff.",
"The fireball is hydrogen burning off. Just after that, the RS-25 main engines slowly spin up to full power, which can be seen as the exhaust gets clearer and the mach diamonds more pronounced. It can also be seen as the full stack leans forward. Assuming startup went well, the SRBs are ignited, explosive bolts detonated, and the vehicle leaves the pad."
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nzhdit | Is there actual science behind the ubiquitous laser miner of sci-fi? If so, By what principle would they work? | Technology | explainlikeimfive | {
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"text": [
"Are you asking if it is feasible to melt trough rock using light energy? Currently, no. This technology is beyond us. However [Plasma torches]( URL_0 ) are a thing, and even Rednecks can teach you how to build them."
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nzjddr | When computer processes (downloads, installations, etc.) reach 100% and stay there for a while, what actually goes on? | Technology | explainlikeimfive | {
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"Have you ever finished the job and then took a moment to put away your tools?",
"It depends on rhe application. In addition to what other people have said. It's entirely possible the programmer fucked up the display and \"100%\" is actually more like 70% Like if you tell someone you will be at their house at 6 but then show up at 6:20",
"[ URL_0 ]( URL_0 ) Tom scott breaks it down really well - basically, at best they are an estimate, and at worst, a terrible guess. As for pausing right at 100% for a bit, that can be intentional as it's a way of visually confirming \"hey, I'm done\". If the progress disappeared instantly the message might not be fully clear.",
"Often it's the antivirus checking the completed file, and some general cleanup/garbage collection.",
"Some separate process that is usually fast happens. For example, after the download it may have to rename the file from a temporary to the intended filename and do an antivirus check (the latter is what probably takes the most time).",
"They receive a very stern letter from the Board of Progress Bar Certification and risk a fine or revocation of their right to use progress bars until 100% means 100% for reals.",
"Software people have to program the installer how to display the progress. It can be things like 1-10% gather all the information you need, 11-60% copy the files, 61-80% verify everything went well, 81-100% clean up after yourself. What if something goes wrong at the end of cleaning up after yourself. Operating systems like windows can take ownership of files (through antivirus, etc.) which can prevent the installer from removing them. Ultimately, to a programmer, progress bars aren’t that important so they get less care than many other areas of the software.",
"Because the programmer doesn't know how the system will handle the program. What you see as \"running in parallel\" is, for the most part, your processors switching between iterating all these programs a chunk at a time. In modern PCs there could be true parallelism but usually you might still end up with the \"multitasking approach\" where you don't really run them all at once but practically do some stuff here, then move over there and then back to something else entirely. Also what is 1% of progress? Say you have 100 files in all different sizes and you want to move them to their specific place. Do you count 1 file = 1% or do you look at the file size or do you look at the system to figure out which jump is the fastest (likely not, but possible). So it's not straight forward what a chunck of progress even means and depending on what definition you pick you can end up with either a fast start and then some delay or a slow start and then finishing instantly. Also as other's have pointed out, the cleanup phase is also part of the progress which is something you cannot really plan all that nice. So it's actually not all that easy to make a good progressbar in advance as you don't really know the system upon which the software will be installed. Also let's be real the prime objective of a progressbar has been and always will be, to indicate that the process is still running and hasn't frozen or been corrupted yet. It's a visiual cue that something is working in the background and that some progress is being made."
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nzkojy | what happens if we charge our phones overnight? Does the battery life really reduce? If yes what's the science/reason behind it or is it just a myth? | Technology | explainlikeimfive | {
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"Part truth, part misleading, part bullshit, part ancient bullshit. * Truth: Batteries lose capacity over time. No matter what you do, it'll eventually wear out. * Truth: Using a battery a lot kills it faster * Truth: Overcharging a battery is a very bad thing. * Truth: Completely emptying a battery is a very bad thing. * Bullshit: Leaving a phone charging overnight is overcharging it. No, lithium won't take that kind of abuse. No modern cell phone (by \"modern\" I mean anything that looks remotely like a smartphone -- so anything made in almost the last two decades) is that stupid, and they'd start lighting themselves on fire if they were. This applies to cheap lead acid/NiMH chargers for round batteries maybe. Cell phones have nothing to do with this. * Misleading/bullshit: Fully discharging and recharging a phone does something useful. Sorta, sometimes. It doesn't do anything good for the battery. What it can help with is resetting the phone's internal estimation of the battery capacity. If your phone randomly dies at 15% it might help it readjust its internal accounting and figure out where the new 0% is. But it doesn't do anything positive for battery health. * Misleading: Optimization strategies, such as charging only to 80%, when applied to cell phones. The reality of it is that pretty much none of them do. A modern cell phone is a 24/7 device. A strategy that applies to preserving the battery life on an electric drill doesn't apply to a cell phone because you can't really not use a phone. * Ancient bullshit: Memory effect. That was a thing on an old, very specific chemistry nobody uses anymore, certainly not on cell phones. It was also barely reproducible in laboratory conditions. TL;DR for cell phone usage: * Don't let it discharge fully. That's very bad. * Plug it in whenever convenient. It'll wear out eventually anyway. * Don't use fast charging unless you need it. It kills the battery faster. * If you want to maximize battery life, and your phone has a mode for it, then use that. If you don't, you can't do the \"stop charging at 80% thing\" by hand on a phone, so don't even try. You'll just kill the battery faster. * Don't buy a ridiculously expensive phone with a hard to replace battery unless you can afford it."
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nzn0fp | When a YouTube video starts buffering, why does the picture freeze first but the sound continue for a brief moment? | Technology | explainlikeimfive | {
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"Sound takes a lot fewer bits than video. The video runs out of bits, and puts up the buffering symbol so you know. The sound just stops when it runs out of bits, but the bits on hand last longer than the bits on hand for video. Not a lot longer, the buffers take the smallness of audio into account, but they are not managed down to the bit, the \"chunks\" of audio are about a second long."
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nztm2a | How do QR codes work? | How are QR codes able to direct me to a website/ fill out correct information on blank fields? | Technology | explainlikeimfive | {
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"QR codes are a really cool way of encoding information in an image. You'll notice of to look at one, there are a few obvious landmarks that all QR codes share, the large nested squares in 3 corners, and the smaller nested squares in the final corner. These landmarks allow the decoder to determine the scale and orientation of the QR code. Once that's determined, the remainder of the QR code is a lot like binary, it's a grid of squares which are either filled or unfilled, like binary 1s and 0s (this is a simplification of the actual encoding mechanism which is quite complex and allows for a bunch of redundancy, which is why you often have a company logo over the QR Code, obscuring some of the grid, but it still works) The decoder then reads the \"binary\" message from the grid, and it comes out as a URL to a website or an app, or some instructions that the reader so can act upon.",
"You'll notice that there are some big concentric squares in usually 3 out of the 4 corners? with maybe a smaller concentric square in the 4th corner? These are the alignment anchors - the scanner detects these 3 relatively easily, and now can determine the extents of the code and its orientation. The relative thickness of the outer black and inner white rings in those gives the scanner some concept of scale. So it knows how big a bit is from the scanner's viewpoint. Also it knows there's a white space - equal to 1 bit's thickness - around each of those anchors, so no data is there. Then the \"bits\" get scanned starting from some known starting location in the code, and keep reading until the scanner reaches the end of the QR code boundary. The bits read are then turned into bytes and then into characters. All a QR code contains, datawise, is literally a string of characters. In the case of a QR code to open a website, its the URL: \" URL_0 \". All the Photo/camera app or whatever is \"reading\" the QR code has to do is throw the URL to whatever default handler your operating system has assigned to handle URLs starting with HTTP://.... if it was just text it would probably open a blank browser tab or a text reader. If it was a Spotify URL, it might open Spotify - what opens to read/take action on what information is in the code is largely up to the device operating system that is reading the code.",
"QR codes are read in a predetermined way (just like English speakers know to read books left to right). The black and white squares correspond to 0s and 1s which computers understand. The computer/phone translates those 0s and 1s into ASCII characters that humans can understand. Therefore a QR code is nothing more than a string of text translated into computer and printed out. Any string of text can be a QR code. You can use your name or a sentence or anything you want (assuming it's smaller than some specified length) The real magic comes when this string of text looks like a website URL. If, after the translation, the QR code looks like URL_0 , most phones will go ahead and open than in a browser for you. Now any website can be printed as a QR code. And the last bit of magic comes from the fact that you can use URLs to prepopulate information on certain webforms. But all that looks like a regular URL, which is just text, which can therefore be used as a QR code"
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nzufv9 | Why are smartphones incapable of setting two timers to run concurrently? | Technology | explainlikeimfive | {
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"> for some reason the iPhone just can't seem to handle that colossal computing task. The technology exists my friend, and the iPhone... from a required computing power standpoint - is more than capable of it. But Apple has decided that _normal_ users clearly wouldn't need such a feature. Therefore you don't get it. By default I should add. There's tons of timer apps in the app store that do this. It all comes back to Apple's iOS design aesthetic - you can only do one thing at a time; by default few apps are allowed to even run in the background. To switch you have to go \"home\"... you don't even have a button choice. You have one button. DO as we say and do it how we say you should do it! Typical Apple. ** In any android's clock/timer app, its right there: \"Add Timer\" and you can have a bunch all going at once. So... TL;DR - why? _Because Apple hates you_ and only pretends to like you because of your money. ** while Im not an iOS developer (so what do I know), my honest software developer suspicion is that iOS is just a garbage operating system - they could totally do this... and have lots of background stuff going on, but I iOS is just not designed to do multitasking very well. So adding lots of background tasks would expose this and shatter the utopian user facade that Apple so polished. If iPhones (or their apps) crashed as much as some androids or Windows ones can, no one would pay $1000 for an iPhone.",
"There sure can be, they just don't care enough to implement it. That's it, nothing more than that. Sorry for disappointing you. [Try third party applications from people who give a damn about that specific issue?]( URL_0 )"
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nzusq5 | Why can't we watch over the airways broadcasts through the internet? | It is 2021, how come we can't just watch network tv (CBS, NBC, ABC, and Fox) over the internet instead of having to hook up a digital antenna and having the hassle of moving it around to ensure a strong signal? Yes, I am aware that broadcast tv can be viewed over paid streaming services like Sling, Hulu Live, and YouTubeTV. There are also stand-alone paid services like Locast. But why can't watching a network broadcast be as simple as connecting directly from your internet where your IP matches to the local tv market? | Technology | explainlikeimfive | {
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"When you have a satellite or cable TV hookup, the signal that the provider is sending out is \"Multicast\". That means they only need to broadcast one signal, and everyone can listen to it. With the Internet, multicast is generally a bad thing. The main difference is that anyone can be the source of a signal on the Internet. If we let anyone multicast their broadcast, it would be very easy to overwhelm all the connections and grind the Internet to a halt. So, multicast isn't generally used. That said, some ISPs do offer IPTV, and that *is* a multicast signal (for the broadcast stuff at least, not for on-demand). However, the ISP is the one controlling the signal. Even if you get, for instance, NBC through that IPTV service, it's still the ISP rebroadcasting the stream from NBC over multicast, so they control everything about it.",
"That's a great idea, and back in 2012 a company called Aereo tried it. Basically they developed a circuit board that had several individual tv antennas on it. Then they would set up their equipment in an office in a major city that had broadcast stations. As long as you were in what was considered the local market for those stations you could sign up to receive those stations. You would pay rent for a specific antenna and live TV would be streamed to you. You weren't paying for tv like cable, you were simply renting an antenna. I was an early alpha tester for the Houston, TX area. I live about 50 miles from Houston. The service worked great. Unfortunately the major broadcast companies didn't like the idea and they took it all the way to the Supreme Court and they ruled against Aereo. I believe they made a mistake, it would be no different than if I rented space on a tower in Houston and ran a 50 mile cable back to the tv in my house. URL_0"
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nzxfi1 | Why are keys of a computer keyboard arranged in that specific way? | Technology | explainlikeimfive | {
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"There are lots of different arrangements, but if you're referring to Qwerty, it's because the letters are offset such that more commonly used keys are next to less commonly used keys. This is because back when mechanical keyboards had arms that flipped around as the keys were pressed it could cause problems if two next to each other were pushed in quick succession. By placing commonly used keys next to uncommonly used ones the chances of this happening were reduced.",
"Real fun fact: the story everyone is quoting here about typewriters jamming has been debunked. [ URL_0 ]( URL_0 ) > While it can’t be argued that deal with Remington helped popularize the QWERTY system, its development as a response to mechanical error, has been questioned by Kyoto University Researchers Koichi Yasuoka and Motoko Yasuoka. In a 2011 paper, the researchers tracked the evolution of the typewriter keyboard alongside a record of its early professional users. They conclude that the mechanics of the typewriter did not influence the keyboard design. Rather, the QWERTY system emerged as a result of how the first typewriters were being used. Early adopters and beta-testers included telegraph operators who needed to quickly transcribe messages. However, the operators found the alphabetical arrangement to be confusing and inefficient for translating morse code. The Kyoto paper suggests that the typewriter keyboard evolved over several years as a direct result of input provided by these telegraph operators. Oh and edit, this line was good: > This theory could be easily debunked for the simple reason that “er” is the fourth most common letter pairing in the English language.",
"On old typewriters, if you would strike 2 keys at the right time too closely together, the striking arms would push against one another and lock up and jam ruining your flow. They organized the keys in a way where it could avoid those lockups in most scenarios based on frequency of hitting certain keys next to each other. This keyboard layout is called \"QWERTY\" based off the first letters in the sequence. There are other layouts, such as Dvorak, which is supposed to improve efficiency and speed up typing so long as you learn that new system, but we're mostly locked into QWERTY now at this point."
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nzzkib | Why are High Ohm Headphones better then Low Ohm Headphones? | Technology | explainlikeimfive | {
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"Think of the electrical coils inside a headphone as a wound up garden hose. Push water (current) through it and the hose expands and can push other things (electromagnetic field). In a headphone, the coils generate a magnetic field to move a diaphragm back and forth, making sound waves. If you want fine control of the diaphragm, you will need more windings or finer wires in your coils. Both of those generate more impedence for the current to travel through much like water having more resistance when going through a longer or thinner hose. Typically, higher impedence headphones have more complicated coils to generate better sound than lower impedence headphones. This assumes you have the right amplifier to drive them and applies to dynamic driver headphones, not planar magnetic."
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o03t8q | when taking pictures of a computer or tv screen on your phone, why is the picture occasionally distorted and streaked with odd light effects that vary if you zoom in or out? | I noticed this occurs sometimes when I am recording a video or taking a picture of a tv/computer screen but not all the time. | Technology | explainlikeimfive | {
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"text": [
"Your TV or computer screen isn't constantly displaying a static image, even when it's displaying a static image; it is getting data for each row of lights and updating them faster than we can typically see (a standard refresh rate for a PC monitor is about 60 hertz, or 60 refreshes per second) - depending on the screen and technology used, it may only update half of the rows (but not like, top half/bottom half, but every other row) at a time. Usually if you take a picture and that's happening, you captured some of the lines in refresh. This is kind of hard to avoid unless you're using a ridiculously fast shutter speed (forgive me, I'm not a photographer so I don't really know what all goes into it, I know some of the terms that are about capturing light for the image) If you're taking video, what your camera is doing is, in essence, taking a picture a certain number of times per second and then playing them back really quickly. So if your capture frames per second is not an exact multiple of your screen's refresh rate, it will have some of that going on through the video. Bonus info: To make this not happen on screen (for instance, if you are shown a picture of a phone screen in a movie it doesn't do this) a movie or TV show's crew will either get specialized cameras that are in sync with the phone's screen, or the editors will go in and add in the animated screen as a special effect."
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o0b3zg | Why are all image files four-sided? | Every type of image file I've known is quadrilateral, even if you have a .png of a circle, there are still transparent pixels filling the corners into the shape of a square. Is this because of some technology limitation that only allows images to be this way? If so, elaborate. Or on the other hand was this decision made purely for convenience and no one ever bothered to try making image files in different shapes? Edit: Thanks for the amazing responses guys : ) | Technology | explainlikeimfive | {
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"It is not a limitation of the technology as such, more a concious decision to limit the file formats to rectangular images. This makes it easier to make the file format as all images can be represented as the same type of data matrix of pixel values and defined using only their height and width. And things like the compression algorithms used only works on rectangular images as they can make quite a lot of assumptions about the relative possitions of the pixels. Not all image formats are rectangular though. I have worked with TIFF files that represent the output of scientific experiments where they need to encode all the raw data but this raw data is not collected in a regular rectangular grid. However these formats are very rare and most image applications are not able to display them correctly.",
"Yes, it's convenience. Computer screens are rectangular, and the pixels are arranged in a grid. You could create a circular screen and a circular image, but why would you?",
"As far as I know there are 2 methods of dealing with digital images. One is raster graphics and one is vector graphics. So lets say you have an analog photography that looks something like that: [ URL_1 ]( URL_0 ) (In case you can't see it or don't want to click the link, it's a simple house drawn with a bunch of straight lines) Now you want to send the information to a friend but you can't send the photo itself but are only able to describe it to them. So the raster graphic approach would overlay that image with a grid and for every cell of that grid it would determine one color and one color only and tell the list of colors and grid positions to your friend. Then you're friend would draw the grid, color it's cells et voilà your friend would have a copy of your picture. Now for that approach using a rectangular shape is very convenient as you only need to give them two coordinates x and y then afterwards you could basically just name colors and your friend might fill them in left to right, top to bottom, for example. So sure if you cut off the areas that you don't need for a circle or that are blank in my example, you'd have less pixels to worry about, but you'd also need to supply your friend with an additional information of where the pixel actually is either on their screen or relative to idk the first pixel. So in most cases you might end up with more information that you need to deliver not less. And that approach is so successful that basically all modern image recording devices use that. Meaning an image is created by having light pass through the lens of a camera that is directed on a grid like pattern, where sensors determine the color by the intensity of the light that passed through a red, green and blue filter for each of those picture elements (or pixels). As well as the vast majority of image displaying devices, like computer monitors which also operate on a rectangulare shape that is subdivided into pixels that change change their color. Now that we've gotten to know raster graphics, the alternative to that is vector graphics. So instead of telling your friend the color and position of each pixel, you tell them to draw simple geometric shapes and where they start and stop. So you basically write them a recipe: \"put your pen at coordinate (0,0) and then draw a straight line to (0,3) with a thinkness of 2\". That way you avoid to tell them any of the blank spaces and if you want to you might even work with general descriptions such as \"half the screen size\" to even avoid having to tell them specific coordinates as to where to place the pen. Which is massively interesting when you want to be able to present an image at different sizes. Because doubling the size of the image is easy, just double the length of the lines, done. Whereas for a raster image, you don't need to know anything about what is displayed on the image and therefor also can't really double it without having it look pixelated. Because you simply drawn the pixels bigger, without adding additional information to make it smooth again or guessing how it could look like. The downside is that you need to describe your picture really well so every line and it's relation to other lines has to be noted somewhere which can get messy real quick. Now those are basically a list of commands how to draw an image rather than the image itself and once you want to see it you still have to feed it to something that essentially translates it to a raster graphic (computer monitor), but as said you can easily rescale it up or down to make it beautiful no matter the size. Edit: fixed some spelling errors."
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o0dt3i | How do Artificial Neural Networks work? | Technology | explainlikeimfive | {
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"Let’s think of something an artificial neural network could do. How about predict the weather? We’ll just tell it to try and figure out how warm each day will be, to make things easier. So the output we’re looking for is “tomorrow’s high temperature.” Now we need to give it some inputs. We can give it things like the last 5 days’ high temperatures, and maybe the temperatures from a city to the west. You could tell it last year’s temperatures for the same day, or maybe the last 5 years. Just any information that you think would help. The system makes its first guess, based on all that data, added/ subtracted/ multiplied together. Then tomorrow we see how close it is to correct. That information goes back into the system, and the system adjusts its math to try and get closer. Over time, the system starts “learning” which data matters, which data doesn’t, and so on. In this example, the learning process can be slow, since it takes a full day to figure out how right it was about its guess. But we could give it all the information from a year ago, and let it guess its way through all the information we have just as quickly as it can do the math. In short, then, artificial neural networks are just self-adjusting math equations, and are only really as “smart” as the information they’re given.",
"It's basically large scale trial-and-error. You have a bunch of individual nodes. Each node takes as input some number of numerical values. It then adds them together and multiplies it but a number called the \"weight\" then produces an output. By having lots of nodes which feed into each other, and by tweaking the weights to get the desired output of the system as a whole (when comparing it to known data), it can become good a predicting and classifying unknown data correctly."
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o0h88u | How does the computer physically store information in the memory (RAM)? | I know that the RAM is for storing temporary information that can be accessed very fast. How is this information physically stored? I do web development (nothing low level like Assembly) and I use variables to store information but how is that physically stored? Are there any elements that hold the electric charge or in any other form? Is it similar to how information is stored on a hard disk which are (as far as I know) magnetic slots that can have a direction? | Technology | explainlikeimfive | {
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"RAM typically uses capacitors and transistors to hold onto an electrical charge. A \"high\" electrical charge (above half a volt) is a 1 and a \"low\" charge is a 0. It's much faster than reading and writing to a hard drive, but is volatile (only works while the computer is powered)."
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o0ixbl | whether ion technology hairdryers do anything | Half of the hairdryers in the shops are "with ions", promising that they dry your hair gently, without frizzy ends, and faster than regular hot air. Do they actually do any of that? How? | Technology | explainlikeimfive | {
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"*not a hair drying expert but I know some stuff about ions, here's my take on the situation. The theory with ionic air movement and improvements in how it dries your hair are that the removal of ions can reduce static electricity. I know this works on a purely scientific level because I do it everyday at work. But when I do it I'm trying to remove my new quantities of static electricity in micromanufacturing processes, we're talking about stuff that's measured in nanometers an angstroms. Seriously, literally microscopic stuff. But the real question is, will that benefit your hair? Maybe. I tend to think not, but the manufacturers of them would have you believe otherwise. If you got extremely frizzy hair maybe they might help, but I doubt it. There's just too much too many factors at work in drying your hair, air speed, air pressure, relative humidity, air temperature, ambient temperature etc etc etc. I can't see an ionic hair dryer producing radically different results than a normal one."
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o0jyy0 | When I’m on speakerphone, how does the person I’m talking to not hear the videos that I’m playing and hearing while we’re talking? | Technology | explainlikeimfive | {
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"Because the phone knows what sound waves it is putting out, and chooses not to transmit them. The computer inside your phone knows that the sound the speakers are putting out “looks” like, the sound waves, so at when it is also receiving sound to send on a call it is “looking” for those same waves getting picked up again. When it spots them, it removes that sound data from the data it is sending along to the other phone on the call."
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o0mj65 | Why does hitting the TV remote make it work? | Technology | explainlikeimfive | {
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"The only way this would happen is if the batteries are not seated properly. The rest of the remote has no moving parts, hitting it should do nothing.",
"Rust/Dirt on the battery contacts or not properly seated batteries can both be solved by a physical jolt. But either way you're better of removing the batteries and reinserting them a few times"
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o0qy6p | What is anti-aliasing? | What does it do and how does it work? | Technology | explainlikeimfive | {
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"If you look really closely at a screen rendering 3d graphics, any lines not at vertical or horizontal angles will tend to look \"jagged\" and like stair-steps rather than a smooth surface. It's especially noticeable if you lower the render resolution way down. This effect is known as aliasing. Anti-aliasing is a way for the computer to interpret this meeting of two different shapes, and average the pixels in the stair-steps to smooth out the image. I used to play with making a similar effect in MS Paint: make an angled black line on a white background, and then out from each black pixel into the white, make successively lighter shades of gray. When you zoom out, it will look a lot nicer than the abrupt change from one color to the next. Photoshop/other full-featured editing programs also do this automatically when you choose a brush with soft edges. Hope all this helps. :)",
"When there is a diagonal line in an image it fades the edge so it’s harder to see the jagged edge of the pixels. It can make lower resolution screens less noticeable.",
"anti-aliasing is basically blending out pixels that make a line, to make the line they're part of appear smoother from further away. here's a good pic of what it looks like both from far away and zoomed in: URL_0"
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o0sy0k | How does turning off your computer with the physical power button cause file system damage? | I was always told never to turn off my computer (or even gaming consoles) with the power button because it can mess up the file system. But I never understood how it happens, or why it happens. Do you think computer technology will ever advance past this obstacle? | Technology | explainlikeimfive | {
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"Files systems are slow. Your computer and game console will sometimes keep data cached in RAM and commit it to the file system at a later time. If you turn off the power before the data is written to the file system then it could result in data corruption.",
"Imagine it like this -- you're at work, filling out and filing your monthly reports. Someone asking you to come by their office after you're done is like shutting down through the OS. You have whatever time you need to complete your reports. Someone forcing you to stop now and come with them is like the power button. Now you have a bunch of reports that aren't fully filled out, or done properly. Except with a computer the reports are files, and unlike our office scenario you can't just come back to them later because RAM is volatile and needs continual power to not forget everything.",
"Basically, writing files to disk takes time. Significantly more time than writing something to memory. So your system is setup to write things to memory quickly, and then to disk eventually. If you hard-stop the system, then it is possible that there was a file in memory that never was written to disk. That means you could lose data. Worse yet, you could have two files that are supposed to be updated in tandem, and one could have been written to disk, but not the other one. This creates an inconsistent state between the two files -- whoever wrote the program may not necessarily have thought of this situation, or even if they did, there might not be a good way to recover. Worse yet, these don't necessarily need to be some text or config files. They could be actual executable code that is being updated. That is really hard to work around, and will basically always require some sort of repair job. Worse yet, it could be the windows update code itself that handles bad system files. There's no backup for that! If that gets corrupted in an update, you definitely need to do an external OS repair to fix it!",
"Computers have a series of tasks that they are completing in their normal operation. One of the major issues is that in order to work quickly with files they are copied from relatively slow long-term storage into \"memory\", an extremely fast form of data storage that has the downside of being unable to hold its data without constant power being available. Normally a computer will copy the files it needs to use into active memory and modify them there as it goes, until at some point they are written back to the long term storage. The physical power button on your computer will, if held down for a period of time, simply cut power to the computer immediately. Any data that is held only in memory will be lost, and if the computer is currently overwriting a file that it modified then it would stop in the middle resulting in a corrupted file. Computers are *extremely* complex and the file that will be corrupted isn't necessarily just your Word document or whatever, it might be a file that is very important to the operating system itself. One process the computer does for example is when writing a file to storage it will keep an index of where the file is stored, which is often split between several different locations. Being interrupted while modifying this index can be bad news even for unrelated files. There are various ways to \"advance past this obstacle\", the most straightforward way being to simply remove the user's ability to actually cut power to the system directly. You see this on phones and tablets where the power button simply requests the device shut down gracefully; the user isn't given the freedom to directly cut power because they aren't considered competent enough to use it wisely.",
"Imagine a doctor falling asleep, in the middle of performing surgery. This is essentially want is happe jng if your computer looses power in the middle of an update or other major action. Shutdown properly allows for it to make sure every can shutdown gracefully and not risk corrupting anything."
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o0vlgi | how does Live Photo starts few secs before I snap photo | So the Live Photo records few seconds before you snap. But how does the phone know I’m going to snap the photo in few sec? Does that mean my camera is always filming me? | Technology | explainlikeimfive | {
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"It is sort of recording all the time, and then immediately discards frames as soon as 1.5 seconds have gone by. It's only 15 fps (frames per second) instead of 60 fps like if you recorded a video, so it's not very intensive to hold this data for a short time and then to discard it.",
"The feed from a modern camera is always running, and continuously running filters / facial recognition to find faces etc (that's what makes smartphone photos look way better than what it's lens/sensor can do physically), so it's more like it normally discard the footage after a few seconds unless you take the photo, that's when it writes in-memory footage into somewhere more permanent",
"There's no way for it to \"know you'll take a pic soon\", so yes when that mode is on, it's constantly recording and temp-saving just the most recent few seconds (like how a closed circuit security cam works, always recording the last few hours and constantly taping over the oldest footage). When you snap the pic it saves the most recent few seconds permanently."
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o0y3dx | Why does it take 1+ hours to charge something when electricity is almost instant? | Technology | explainlikeimfive | {
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"If you open your bathroom tap, water comes out immediately, because there was water in the pipes, and that water is under some pressure so it wants to come out if you give it an opening. So in that sense, the delivery of water is \"instant\". However, it still takes a good while to fill up your bathtub with it, because the pipes only allow a certain amount of water through them, and the pressure only pushes it through the pipes at a certain rate. To speed up the flow, you would need to increase the pressure, but if you increase it too much that will damage the pipes. To prevent that you would have to make the pipes stronger or wider. Electricity is very analogous to this. The water pressure is analogous to voltage. The higher the voltage, the faster electrons are getting pushed through your outlets. The pipes are analogous to the wiring, which has a certain *resistance* that puts a limit on how many electrons can pass through every second. If that flow of electrons (the current) becomes too strong, it damages the wiring. So that puts a limit to how many electrons can flow out of your power outlet every second, just as there is a limit to how much water can flow out of your faucets. And so just as it takes a while to fill up your bathtub with water, it also takes a while to \"fill up a battery with electrons\" (that's not precisely what happens but it's close enough). (The limits aren't just in your power outlets of course - they are in all the wiring that is involved, including the charger you're using, which has its own limits to how much electric current can pass through.)",
"It depends what technology is used to store the charge. Capacitors charge and discharge in a very short time (milliseconds to seconds) but hold a very small charge. All of the common battery systems in household use use chemical reactions to store energy. Those chemical reactions need time to happen. Still there are often specific quick charge routines that cut the time far shorter often at the price of a reduced battery lifetime."
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o13cep | How does toothpaste get the pattern in there? | Surely it all mixes up when inside the tube? | Technology | explainlikeimfive | {
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"text": [
"Because Toothpaste is an interesting fluid. Inside the tube when you're not squeezing it, the toothpaste stays in it's solid colour blocks. When you squeeze the tube, the shear force you apply causes the fluid to flow out of the nozzle. The toothpaste has something known as 'thixotropic rheology'. This means that when you remove the pressure, (i.e. once it is on your toothbrush), the stripes regain their thickness, enabling the product to look like a three-striped cylinder."
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o16xop | how does your car radio know to send sound out of specific speakers? | I'm thinking of when songs are coming from only the left side, or right side, or maybe the drums sound like they're behind you. Not all stereos are set up for multiple speakers, but the same sounds come out of them. | Technology | explainlikeimfive | {
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"Left vs Right is encoded in the FM radio signal, or music player source. Things like the drums are also that sort of an imaging evvect, plus better bass response from larger speakers in the rear.",
"Already some good answers here. I'll add that some radios (and especially when you get into aftermarket territory or optional name-brand factory radios) use bandpass filters to target certain speakers like sending bass to woofers intended to provide some boom-boom or sending high pitches to tweeters.",
"When you tune to a radio station, such as FM 99.9, you might think that radio station is exactly at 99.9 MHz. In actuality, it's a range of frequencies around that point (which is why the next channel isn't for 0.2 MHz above or below). In that frequency range, there are multiple signals being sent. You can get a left channel sound, a right channel sound, and even quadraphonic sound.",
"* Most music we hear is in a format called \"stereo\", which means there are two channels of audio, called \"left\" and \"right\". * When a radio station broadcasts a \"stereo\" signal it's actually broadcasting two signals at the same time. * And that means the radio is receiving two signals at the same time. * So it just plays the left signal on the left speakers and the right signal on the right speakers."
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o1764j | Why do inconsistent computer glitches happen? | I understand "stable" glitches. By stable, I mean glitches that occur whenever you put in an unexpected input. For instance, a programmer may not have expected users to enter "0" into a field. So **every time** I enter 0, the program glitches. Or **every time** XYZ situation happens, a glitch occurs. But I don't understand unstable glitches. That is, glitches that appear to happen randomly even if you perfectly replicate the scenario. Why do these happen? I wrote a simple autohotkey script for example: > +Up::{Volume_Up} It seems like 90% of the time it works, and 10% of the time it doesn't. As a test, I used the function in as controlled of an environment as I could do. I am not opening new programs or doing anything new. I disconnected from the internet, closed all backgroun processes, etc. The only thing that changes is the time. I just sit on my Desktop changing the volume, and sometimes it randomly doesn't work. That wouldn't be due to inconsistency between the layers, since nothing is changing except me pushing the volume up button. To clarify, I am not looking for help troubleshooting my script. I am just curious about the general reasons for unstable glitches. I mean, code is a logical flow of instructions, so if you replicate the glitch inputs, the glitch should occur again. But some glitches occur once and can never be replicated. Why? | Technology | explainlikeimfive | {
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"Most things about computers are deterministic, meaning they're predictable (input A results in output B). However, there are two reasons we observe instability: 1. Most *observed* instability is *actually* deterministic. That is, if you perfectly recreate the conditions, the glitch will occur in exactly the same way. However, computers are very very complex and it's very difficult for a human to understand all of the variables and interactions involved, so we just throw our hands up and call it a glitch even though everything happened the way it was \"supposed\" to (at least, according to the computer). Basically, the complexity exceeded our ability to comprehend it, even though it was operating \"perfectly\". 2. Rarely, instability is due to \"random\" factors. A neutrino or ionizing radiation hitting juuust the right place inside a chip to flip a bit, or malfunctions due to overheating or a bad component (such as a capacitor drying up) causing signals to go outside their intended range. These are pretty rare, because a lot of storage and communications inside the computer are protected with error detection and error correction algorithms, so that even a wrong bit in RAM or traveling across the bus can be corrected by clever hardware and software.",
"Unpredictable software failures are often caused by one of several things: 1 - Memory use after free. The program puts important information in a block of memory, then later (because of a bug) tells the operating system \"I'm done with this memory, feel free to put something else there\". But since the program still thinks that memory is for the original purpose, finds incorrect data there. If it takes a long time before some other data it put there, things might work for quite some time. But once something else is stored there, you might have your glitch. 2 - Memory smasher. The software wants to write to memory, but the memory address it tries to use is totally wrong (because of a bug). If the random memory it's writing too is rarely used, then things will appear to work, but if it accidentally overwrites something important, there's your glitch. Sometimes, the glitch can happen minutes or hours later. 3 - Race. Computers can do multiple things at the same time. Software is **supposed** to use a *lock* to say \"Nobody touch this, I'm working here\". But, if that step is skipped, two parts of the program can. modify the same data at once and leave it in an inconsistent state. The chances of two parts of the program changing critical data at exactly the same time are sometimes small, so this glitch feels occasional and random. \\*edit to a word."
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o18ik4 | How do CDs and DVDs work? | Technology | explainlikeimfive | {
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"text": [
"A laser shoots at the shiny side of the disc and based on how it is reflected back, that part of the disk is read as a \"1\" or a \"0\". There are two main ways of encoding information on the disk. The first is to actually press little indentations onto this disk. This is permanent but reliable. The second is to have a special kind of dye. You can \"burn\" information into this dye with the laser, allowing you to write and re-write information to do the disk."
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o1h55o | What is in metadata and why would someone ask a phone company for it? | Technology | explainlikeimfive | {
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"You call someone. The words you say to them, that's the data. The originating phone number, the destination phone number, the time you called them - that's the metadata (the data about the data). It can tell people information without having to access the content of the call (which is more difficult to get). If you're calling a tow truck company at 5pm, I can infer that your car broke down on your way home from work. I can then see what other calls you've made around that time which are probably related.",
"Phone metadata is calling number/called number/number of rings before answer/ length of call/who hung up/ ... . Let's say some reporter leaks secret information. That's OK, in the US, but giving the data to the reporter is a crime. So, you get the reporters metadata to see everybody they called on the phone. Reporters like to talk on the phone, because that way \"The Man\" can't know what was said. If you text them the data includes what was said. Then you think Senator Dumbo was the source of the leak, so you get all their call metadata and see if there are any connections. Sure, you might find they both ordered something from Comet Pizza, but you might also find out that they have been using Joe Smith as a courier. It's a source of leads, not a smoking gun (most of the time)."
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o1itns | Why does speeding up recordings make them higher pitched? | Technology | explainlikeimfive | {
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"text": [
"Sound is a frequency of waves in the air. The closer together those waves are, the higher the pitch. When you speed up a recording of someone/something then those waves are moved closer together. If you slow down a recording those waves spread out and lower the pitch"
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o1ozva | Why there exist so many USB partitions? NTFS, FAT32, Extended Journal and some OS recognize only some of them whereas other USB peripherals never have this issue. | Technology | explainlikeimfive | {
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"First, those are examples of *filesystems,* not partitions. A partition can have a filesystem on it, though. A lot of filesystems exist because computers have been around a long time, and some of them get phased out over time (FAT to FAT32 to NTFS), and sometimes some people want to use a different filesystem for a different operating system (Linux can use ext2/3/4, for example). Some OSes just don't know how to read certain filesystems, while others do.",
"this is not a problem with usb peripherals in general but one of storage media (such as hard drives, memory cards and usb memory sticks). this collection of different partition types has grown historically because every manufacturer wanted to develop the perfect format for their needs, but no one voluntarily makes a universal solution with an acceptable license",
"Each file system has different advantages and disadvantages, as time goes forwards, and files sizes are increasing, older file systems won't work as quickly and support large files. Each operating system has adopted it's \"own\" style of file system, and usually it's not compatible with other systems as the code each operating system runs on is different. The \"Fat16\" file system is probably the most widely supported, but as a result, it's maximum file count and maximum folders are low, it can't support files larger then 4gb, limited maximum path names, and a few other things. Usb is different as it's hardware only, and USB is just a serial connection, that's really fast and follows a robust standard that makes default or blanket drivers possible for operating systems to at least get working"
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o1p3gp | Why was it so hard to bake a cookie in space? | I just red a article talking about the first cookie being baked in the space station (that was a while ago), but I don't understand why it wasn't done before and why is such a big deal now. It looks like a company put a lot of effort just to send this cookie to be baked! And also they were not able to eat it. I would love o understand more about that! Thank you! | Technology | explainlikeimfive | {
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"Pretty much all of the things you take for granted about cooking here on Earth are different in microgravity, and doubly so because of the safety concerns on a space station. In microgravity, there's nothing to hold a cookie to a pan. A system needed to be devised to keep the cookie stationary so it didn't float around inside the oven. Crumbs are also a big risk in space. They don't fall, so as they float around the station, they can get lodged into sensitive equipment or even accidentally get inhaled by the astronauts or get in their eyes. A system needed to be devised to minimize crumbs. Heat is a huge deal in space for 2 reasons. First, a fire would be far more catastrophic on the space station than on Earth, so an oven needed to be designed that would eliminate any risk of fire. Heat rejection is also a big deal, because the electronics in the station generate a great deal of heat, and that needs to be accounted for. You can't just open the oven and let it cool off, the station's climate is very tightly controlled. Even the chemistry of baking in space is different. On Earth, we rely on gravity to allow dough to rise. In microgravity, the gas bubbles don't rise, so everything is kind of clumped together. What would that look like? Would it be palatable? Would it hold together or just crumble? Would it heat evenly? We have to test to see. As for why they couldn't eat it, there are 2 reasons. The first is that if they eat it, they can't send it back down to Earth to be analyzed. We want to know how well the oven works, and we can't do that if there's no cookie to analyze. We also want to make sure this unusual cooking method fully cooks things. We don't want astronauts getting food poisoning in space."
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o1wjnx | How are game engines made and why are they necessary for games and why are there so many of those? | Technology | explainlikeimfive | {
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"A game engine is a lot of reusable code that different game studios can use to make their games. Game development teams do not want to spend a lot of time reinventing the wheel with each game. Rewriting code on how to handle physics, how to handle a hitscan bullet, how to handle a projectile weapon, etc. This code is essentially going to be the same in every game that uses them, so why spend a lot of time writing it for each project? This leaves the game developers the time to actually code the stuff that makes their game *different* from others.",
"I want to add one extra point: Most game engines are basically reusable pieces of code that every game needs, but there is one extra thing game engines usually ensure: Platform interoperability & #x200B; Kind of like how a web browser ensures you see the same webpage no matter what operating system you use, an important responsibility of a well designed bigger game engine is to ensure that the game looks, feels and acts the same on all platforms the game ships on (PC, Console, Mobile, etc.) without the game designers or the developers having to write a single line of code to achieve it.",
"Game engines haven't always been a thing. They were created to reduce the complexity of developing every game from scratch. Sometimes games will want to do some cool new feature, so a studio will make a new engine, or modify an existing one to meet that goal.",
"Suppose you want to make a game. You have a cool story, you've drawn some cool character designs, your notebook is full of great ideas! Now, write the computer code to make all that magic happen on the screen. But! You're a designer, not a coder. You don't know how to code. Or, more realistically, you're not interested in learning to code or building the HUGE team necessary write all the code. So, you license the code from someone else, who has written the program. That's the game engine. This story also works the other direction. Suppose you're a coder. You have figured out a really clever algorithm - perhaps a very, very fast way to computer the inverse square root. (John Carmack actually did this.) This super quick algorithm is now a core element in some software you're written that draws 3D objects on the screen. This software would make a really cool game! But! You're a coder, not a game designer. You don't know how to design games. It doesn't really interest you. So, you offer up your software for other people to use to design their own games."
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o1zroo | Why does HMDI need such high bandwidth compared to Ethernet? | When we stream 4k video from Netflix for example, they recommend a minimum speed of 25 mbps.But HDMI 2.0 has a bandwidth of 18.0 Gbit/s How can we recieve 4k video with a connection speed of only 25 mbps when we need 18.0 Gbit/s to send the video to our TV? I think it is to do with compressed vs raw 4k but do we really compress it to this an extreme? I would have thought this would result in so much loss that we are no where near 4k in the end. | Technology | explainlikeimfive | {
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"Netflix, Youtube etc. all compress the hell out of their videos. Video compression is a lossy system, so some of the detail in the image goes away when it's compressed--the critical thing with the compression algorithms is to try and ensure what goes missing is stuff you won't notice. Nonetheless, if you were to run the uncompressed 4K video alongside the streamed version you would almost certainly be able to tell the difference. As for the bandwidth requirements, 4K video is 3840x2160 pixels. You need 3 bytes to store each pixel, so each uncompressed video frame is nearly 24Mb of data on its own. If you're streaming that video to HDMI at 60 frames per second, then you need a minimum bandwidth of a little bit over 11Gbps. HDMI gives you a fair bit of overhead there, but certainly not so much that you could say 18Gbps is overkill.",
"You stream compressed video over the internet. But then what happens? Your computer decompresses that video and sends whole 4k frames to the screen. As smart as your screen is, it's supposed to be a relatively dumb output device, so that it can operate independent of whatever video format you're sourcing, or how much computing power is required to reconstitute the original frame data.",
"4K video is 3840 × 2160 pixels with 3 colors and 8 bit per color. So you need 3840\\*2160\\*3\\*8=199,065,600 bit for a single frame. At 60 frame per second that is 11,943,936,000 bits or 11 Gbit/s The first 4K video at 60 Hz on Youtube I founds was URL_0 it is 961.43 MB for 5:13 video The amount of data per second is 961.43*1024^2*8/((5*60+13))= 25,767,000 bits per second. This includes audio so the video size is smaller That is a compression range of 463:1 even if audio is included in one but not the other. So the answer is compression that reduces file size but factors of a couple of hundred times.",
"> How can we recieve 4k video with a connection speed of only 25 mbps when we need 18.0 Gbit/s to send the video to our TV? * Compression. * You are downloading a map and a set of instructions that tell your device how to recreate each frame of the video. * Once that frame is recreated, the data for over 8 millions pixels needs to get from your device to the display. * Also up to 8 channels of audio, plus other data, and the HDMI spec also includes room for a 100mbps ethernet link embedded inside the HDMI link",
"Compression: the information sent over a video cable is essentially completely uncompressed video: an uncompressed image is being transmitted for each frame."
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o20z4y | Why can satellite television service easily play high quality movies/shows, while satellite internet service buffers videos constantly even in low quality? | Technology | explainlikeimfive | {
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"Satellite TV is broadcast; the satellites \"blindly\" send TV just once, and everyone watches it at the same time. Easy peasy, but you have fewer choices of what to watch (\"500 channels and nothing on\"). Satellite internet is two-way. Unfortunately, the delay between transmission and reception for geostationary satellites is about an eighth of a second each way. So an eighth of a second from you to the satellite, plus an eighth of a second from the satellite to the ground station (where the satellite gets *it's* internet connection), plus however much time it takes for the normal wired internet connection to complete, plus an eighth second for that data to get uploaded to the satellite, plus another eighth of a second for that data to get back down to you. So you're at more than half a second for a full back-and-forth data exchange. This is a problem for internet traffic, because either side sending data needs a reply for confirmation that the data was properly received. The longer the transmission delay, the more difficult it is to send large amounts of data, because any lost or corrupted data will incur a large \"penalty\" delay as acknowledgements are delayed more than half a second, which means re-transmissions are delayed more than a full second. If everything was working perfectly, internet protocols allow a lot of packets \"in-flight\" with occasional receipt acknowledgements, but just a single lost or corrupted packet will make the whole thing just grind to a halt for at least a full second. Additionally, whenever a delay like this happens, internet protocols automatically slow themselves down (because there's no point in trying to stuff 100Mb/s through a 10Mb/s connection). Plus, you're sharing limited bandwidth with a bunch of other satellite users. Which, BTW, is why the new Starlink satellite internet is designed to solve this problem by using satellites in Low-Earth Orbit: so they are much closer and have much less delay. (It also uses a *lot* of satellites -- instead of just a handful of traditional satellite internet satellites -- to allow more bandwidth for more users.) Edit: fixed delays, thanks koolman2",
"Satellite TV is one-way. It beams content out, and doesn't care one bit whether anyone is receiving it. Satellite internet requires 2-way communication, which means you have to exchange a bunch of signals with a satellite 35,000km away, and that takes some time.",
"Satellite tv doesn’t care about latency between your action and a change on the tv, no matter what people do, everyone on that channel is watching the exact same part of the same show at the same time. Since the message isn’t custom, it can be made faster.",
"Most of the commons have addressed the obviously needed bidirectional aspect of satellite Internet. But that’s only part of the reason it’s so slow for video streaming. The biggest reason is that there is only a finite amount of bandwidth on a given satellite or transponder. This is not an issue when broadcasting video to whoever wants to pay for it and tune it in. But when you want to have individual access to data it must be shared amongst many users, and therefore each user only gets a small sliver of the satellite’s available bandwidth. It would be like having one, let’s say cable, internet connection to a city for all to use. Each user’s speed would be quite slow.",
"Satellite tv: there's a band playing music (broadcasting). Anyone can sit there and listen. But you're gonna be listening to the same song as everyone else. Satellite internet: you go to the music shop and pick a song to listen to on your headphones. The shop attendant (or you yourself) has to dig around and find the music you want and put it in to your listening device. There's also a bunch of other people in the shop that the attendant had to take care of as well. But you're also listening to your own choice of music that can be different to everyone else",
"To send 500 channels to 500 million people only uses \"500 bandwidth\", but 1 million people using 1 connection each uses \"1 million bandwidth.\". That's 1/500th the amount of users using 2000 times more bandwidth or 1,000,000 times more bandwidth total. That assumes that each user is only using the same amount of data as watching one stream."
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o21wrm | How do Bone Conduction Headphones work? Are they dangerous? | Technology | explainlikeimfive | {
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"No they aren't dangerous. They use vibrations in the bone or skull to generate sound. This means you could listen to music while not having buds in and thus hear all ambient sounds aswell. Very convenient on a bike for instance. Some hearing aids will have a screw in your skull and attach the device to it. The vibrations will travel to your inner ear and make you able to hear better (as I recall, correct me if I'm wrong)",
"Head bone is connected to the ear bone. Have someone tap on your head with a spoon, then tap on their head. When they did it to you, it was loud, when you did it to them, it wasn't. You can also tap on your knees and compare the sound to someone else doing the same. The difference is bone conduction. You can experiment wearing ear plugs. Sound travels through a medium as a wave, just like ripples in water when you drop a pebble in it. Air is the most common medium, but it doesn't have to be. When you put a string between two cans, the string is the medium. In space, the medium is gone. A loud speaker a foot in in front of your would give you no sound. If you put your forehead on the speaker cabinet, your head becomes the medium, and you will hear it. Bone conduction. People who are around very loud things can only lower the sound so much by combining earplugs and earphones (about 40db max off the top of my head), because bone conduction will still make it loud. Covering the head with some types of helmets can further attenuate bone conduction (of which the skull is the primary contributor). Even then, you can only do so much."
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o24fbk | Why games made with C++ are more optimized? | C++ is the language used in almost all AAA titles. I seen youtube tests that show C++ to execute tasks faster than C# or Python for example. But i heard C is faster than C++ also, so why C++?. And what makes C or C++ faster than other languages (except assembly and machine code of course)? | Technology | explainlikeimfive | {
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"Python is interpreted, not compiled, so the interpreter is effectively turning the source code into machine code as you run the program. This slows it down a whole lot, and other interpreted languages have the same issue. With C or C++, you compile the code into machine code, so you only do that work once per platform, instead of every time you run the program. Now, you can write something in C and C++, and have them both the same speed, or one faster than the other, depending on what compilers and settings you use, because modern compilers are really good at optimizing code down to equivalent instructions that run faster. Which one ends up faster usually is a question of how clever the compiler is rather than anything inherent to the language.",
"C/C++ is a language built on the assumption that the developers will handle EVERY aspect of their program, this includes aspects as low level as managing memory and basic I/O(2 huge areas where bottlenecks in speed are common), if you ignore to handle any of these your program will not run at all or it just crashes when it encounter an unexpected situation, this increases complexity but because everything is managed closely you cna fine tune its performance to what you want it to be other languages like C# and Python implement automated systems to deal with some of this basic tasks so that the developer doesn't need to, but these systems are not specialized for all needs(or in some cases handling them is mandatory even if the program doesn't use them) so performance is not the best it can be. as a bonus both C and C++ have the ability to indent code from other languages most notably Assembly listings, this enables a savvy developer to implement code that is accessed VERY frequently(and hence could become a bottleneck) in Assembly in order to make sure this code is optimized at the lowest possible level before actual machine code.",
"Imagine you are writing a recipe for a Pie. In assembly you would write \"take 5 steps to the fridge, open fridge with your right hand, grab an egg...\" and it would depend on your exact kitchen. In C/C++ you would write \"Get an egg from the fridge.\" In Python you would write \"make a pie crust\" and you leave the interpreter to figure it out at run time, which is going to take time.",
"It is not universally true. However the closer the programing language is to the machine code which actually runs on the processor the more control the programmer have over the code which allows them to write more optimized code. It is things like not following conventions when it would hinder performance, taking minor shortcuts, understanding how different code will get executed in the processor and therefore how it will perform, etc. It does not mean that all C and C++ code will be fast. In fact it takes longer to write code in these languages so there may not be enough time in the project to do other larger performance improvements. And more modern compiler for the higher end languages like Java and C# can actually get better insight into the code then the developer and may do more performance optimization then most people will do on their own. Most AAA titles is written in a number of different languages depending on which works best for the given scenarios. The core of the game engine might be written in highly optimized C++ code that have been perfected over many years and is used for several titles. But the world interactions, animations and scripts are usually written in their own high level language specific to that game engine. Even things like the AI might be written in a completely separate language which is designed to make it quick and easy to work with the AI."
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o24gkq | how can an iPhone be so hard to hack when entire banking systems and other massive companies can be successfully targeted? | Technology | explainlikeimfive | {
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"Big companies have many separate systems, many of which have to talk to each other, which means many potential vulnerabilities (often the employees themselves) and you just need one. Compare that to a single hardware device with strong encryption that has a single owner/user.",
"Banks have a much, MUCH larger attack surface than an iPhone. And a whole lot more of the weakest point in any system: the humans who need to access it. There's an old adage in cybersecurity: What's the easiest way to get an employee's password? You ask them for it. You'd be shocked how many hacks are pulled that way. Kevin Mitnick got famous doing just that. With any large organization you're pretty much guaranteed to have someone gullible enough to just give you their password, especially if you create an employee ID for some bogus IT support company.",
"Apple is a monoculture. That means that only specific, Apple-targeting, techniques work. It's not true that \"entire banking systems\" have been hacked. Some companies have had some disclosure problems, where their transaction records leaked out, but it's not like hackers just transferred all the money out of their bank accounts. That mostly happens in movies. That said, there are many companies with many software systems. Hackers don't care if the take money from Target or Walmart, so they can attack all the companies and just see where they get lucky. Attacking Apple is harder, because there is only the one Apple."
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o27iz9 | What is an api and why is it useful? | From what I understand, it is a package of software that another company creates, so that a startup can use it and doesn’t have to code as much backend?? I’m only partially understanding this... edit: thanks everyone, this conversation has helped me understand the nuance | Technology | explainlikeimfive | {
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"ELI5 Answer: Think of an API like the controls to a car. You've got a gas pedal to go forward, a brake pedal to stop, a steering wheel to turn, etc. You've also got information about the car - how fast it's going (speedometer), how fast the engine is turning (tachometer), how much gas is in the tank, etc. You don't need to know *how* the gas pedal makes the car go forward or the details of how the fuel tank reads its level. In fact, the 'under the hood' operation varies wildly from car to car, but since the car's interface is (roughly) the same, you can get in just about any car and drive it. The set of controls and information is like the car's API. \"Turn this wheel to make the car go to the right. Look here to see how fast you're going.\" is like a website's API saying, \"Give me a string of text and the ID of a parent comment, and I'll post a reply to that comment\".",
"API stands for \"Application Programming Interface\". It isn't so much a piece of software that you create, but rather the interface that programmers can use to interact with the software you created. API's take a lot of different forms, but broadly, they tend to fit into one of two categories. A **Web API** is an interface that works through the internet, in most cases speaking the same language that your web browser uses (HTTP/S). In this case a company will have software running on their servers that provide some service and developers and users send requests to this API over the internet. For example, you could send a request to Twitter's API to get a list of tweets from a particular user. A **Library API** comes with a code package or library that someone creates. These are re-usable bits of code (usually for some programming language or other). But for developers to be able to integrate that code into their project, they need to know how to use it and that's where the API comes in. For example, say I'm writing a Python program and need to do a bunch of math on large data-sets. That will be a real pain to do myself (especially if I want it to be fast), so instead I could use download the numpy library, and use the functions it exposes as parts of its API to do all the heavy-lifting for me. EDIT: Replaced the last example with something a little easier to understand.",
"An API enables other developers to interact with your application programmatically. For example, if a developer wants to create an app showing the weather in their area, they can do have their computer ask the National Weather Service's API what the weather is, and the API responds with the answer. Why is it useful? Well, in this example, imagine every time you opened the weather app, some poor chap has to run over to the weather office, check the instruments, record the data and send it to you. Inconvenient right?",
"API = Application Programming Interface, which I feel does not help anyone who doesn't know what those words really mean. Application = for your apps Programming = intended for programmers / other software to use Interface = a specification for how you should talk to this piece of software. what endpoints are available, how you should format data going in, what it looks like on the way out, how you login or authenticate with the API, etc. This \"interface\" is what you or your application \"talk to\" to make stuff happen or retrieve information. These days, an API is often contrasted with an SDK (software development kit) in that you have to install SDKs on your own machine, whereas most modern APIs are just HTTP requests / web pages you load to \"talk\" to a piece of software or a service. This is not always the case, but it is the modern, trendy usage of the terms. **Since we're on Reddit, why not take a look at Reddit's API?** [ URL_4 ]( URL_3 ) And if you're logged in, you can even load this URL to see your current profile data: [ URL_0 ]( URL_0 ) I don't know what's safe to share from that response, but you'll notice it's a bunch of { data: { in: { curly: brackets } } } You might be wondering, why that weird curly brackets data instead of just a plain paragraph that says something like, \"You are /u/thefuckouttaherelol2 and you've been using this app for 3 months. You have the following features enabled, etc. etc.\" This is because most modern APIs follow the same protocols, which in programming, are just standards for how different pieces of software or hardware talk to each other. For example, Reddit's API appears to be a [RESTful API]( URL_2 ) that returns a [JSON]( URL_1 ) response. Since these are very well-known standards that are supported pretty much everywhere, it becomes really easy to write applications that communicate with Reddit and other APIs that use the same standards. This basically means I can write a piece of software that makes a **request** to Reddit's API in a well-known format. Reddit returns JSON as the **response**. My software understands both the HTTP/Rest structure requirements as well as the JSON Reddit responds with, and can convert the JSON into actual data in my program. This back and forth translation of internal program data (ex: data in a C++ or Java program) to a general purpose format (ex: JSON) and vice versa is known as **serialization** and **deserialization** \\- I can turn stuff into JSON and JSON into other stuff pretty easily because this is all standardized. XML is another popular serialization specification you may have heard of. Again, I have tools for all of this stuff. I never have to write any of it myself unless I'm deep in network programming or something like that. The tools to convert my data to/from JSON, make the HTTP requests to the server, etc. is almost always available in my programming language and platform of choice. Pretty much out of the box. Reddit, Shopify, Google, Amazon, Fidelity, etc. all publish documentation and usually offer tutorials on how to use their APIs. Most of the time, you need to sign up for an account, login through your program by calling the API with your username + password, save your login token (kind of like a cookie session ID in your web browser, but instead it's for your app?), and then supply that token for all future API requests until it expires and you're \"logged out\" by the API. Some (comparably far fewer) APIs, however, let you use them freely without requiring an account or any username/password credentials! Wild. I know this was beyond eli5 but I hope this helps someone. If you have any additional questions, just let me know! :)",
"An API is a way to expose tools you made to the world without a user interface. It can be over HTTP as others may mention but the word is not that limited. This means others can create UI for your product, or use it in automated ways. For instance you can go to google map to find out a location of a business, or other sites could use the google maps api to offer it from their site. Other places like universities may use the google maps api to process large data, without any user interface, and instead with scripts",
"An API is something released by software developers so that other software developers can use what they wrote, without needing to understand how it works. Take Steam matchmaking for instance. Game developers need to be able to use Steam so people can join/create viewable games from within their own game. They don't want to know literally every single line of code that makes Steam work the way it does.",
"Think of a candy store, and now imagine some of the candy is behind the counter. The store attendant is like an API, the candy behind the counter is the stuff you want to interact with, and you are the third-party program trying to gain access to the candy. You can ask the API to GET you certain types of candies and describe them for you. You can ask for a list or INDEX of the candy behind the counter. You can ask the API to order different sorts of candies that you find are not currently available. And finally, you can ask the API to give you some of that candy. You then can consume that information and more importantly, the candy, however you like. You can share that candy with your friends (other third-party applications) or analyze it on your own. Without the API, you would have no way of legally accessing that candy and all of the information about it. With the API, you gain a whole set of capabilities inside the candy store, and you can do whatever you want with that information (candy) outside of the candy store. Less ELI5: APIs are not just for startups, they are for anyone that has a need to gain functionality and access to certain systems, for which they lack direct access. They facilitate the flow of information and functionality between various systems. In most cases, startups could not code this functionality into their \"backends\" no matter how much work they put into its development, because the functionality (and more importantly the data) is proprietary to the third-party system they are connecting to through the API (payment providers, analytics data houses, CRMs, etc).",
"An API allows two pieces of software to talk to each other easily. So, if you're developing software A and would like to interact with software B (e.g. a social network), you would use an API by B.",
"I like the menu analogy at a restaurant. You want to provide a menu so that: - people know what is available at the restaurant (something you control) - you serve up the order instead of having the customer go into your kitchen and do who knows what. (Not in your control.) You want to provide an api so that: - people know what is available from the interface functionality wise (something you control) - you serve up the data/complete the request instead of having the client go into your system and do who knows what. (Not in your control.)",
"The API is a contract. It describes a series of functions/methods that are available to you, how you're supposed to call them and what you should expect back. The implementation of a contract/API is done in a library. You can have different libraries implementing the same API. The car example from /u/bendvis is spot on.",
"When you use a program, you are clicking on a Graphical User Interface, with buttons, text fields, and all kinds of controls. When a program uses another program or software library, it uses an API. Basically it's just a set of routines that other programs can call.",
"Lets say you're making a controller for a sprinkler system, you can set a timer relatively easily, but wouldn't it be nice if it could automatically check the forecast, and adjust how much it waters based on how much it's going to rain, or how much it's rained in the past few days? Well, that's where APIs come in. You can make a request, and get the desired information in a defined format. Example: URL_0 If you didn't have an API, you might have to buy a weather station to measure the rainfall, or you might have to scrape the data from a human readable web site, the format of which can change and break your program without notice.",
"APIs are not just for startups to reduce the amount of code they need to write they are for anyone trying to get data from another source. Application programming interfaces are just ways to access data from someone else",
"Armor Piercing Incendiary. The idea is you're shooting at lightly-armored vehicles or positions, and the round is able to penetrate the light armor and have a small explosion on the other end of the armor. Little bits of burning shrapnel going in different directions have a better chance of hitting something or causing mayhem than one solid armor-piercing bullet going in a straight line.",
"Think of the buttons on your microwave. They're an interface so you can heat food in your microwave without knowing anything about magnetrons or mains power or shielding -- you just gotta know how to use the buttons. An API is the same thing -- you don't have to know how this software actually works, you just need to learn how to use these buttons (the API)",
"APIs are a set of protocols (written as back-end code) that enable different software systems to connect and share data. If you have Siri or Google Assistant, for example, imagine asking it to play a song. The reason digital assistants are able to connect to your Spotify account or YouTube when they play music is because of API integrations. Tech companies use internal APIs as well to optimize software development within their own business. A non-technical example of an API would be a waiter. Waiters take orders from the customers and send them to the kitchen, and eventually give you your food. Essentially, APIs, or application programming interfaces, act as a liaison or middleman, accepting and fulfilling requests between different software.",
"Late to the party here but the way I like to explain APIs is like this. You ever go to the bank after hours, and only the ATM lobby is open? That ATM allows you to interact with the bank in various ways: you can deposit or withdraw money, move money from one account to another, etc. Importantly, your ability to interact with the bank in a way that is dangerous to the bank is severely limited through this ATM interface. The scope of your interactions with the bank through the ATM is much more limited than say, if you walked into the actual bank with a gun and started making demands, or if you had access to a back office computer. The bank is the software company. You are the third party company. The ATM is the API",
"So I think this is the simplest way I can explain it. Think of web development or any other application with 3 main \"layers\". 1. UI 2. API 3. Database I'm going to explain these out of order The bottom layer (#3 Database/backend): A database is a collection of data often stored in tables (kind of like an excel sheet) there are rows and columns that hold data. i.e. | City | population | | New york | 69 | | Los Angeles | 57 | The first layer (#1 ui): The top layer is the UI (user interface) it's literally what the user interacts with, any thing you see on the web is part of the ui (i can't think of anything that isn't but there may be someone out there to prove me wrong) i.e. buttons, text boxes, anything you can see on an application The seccond layer (#2 API): The api connects the two of them. Imagine an application that displays new yorks population everytime you click a button. The button is UI, the population number is stored in the database, and the api would be the code that listens for the button click and then pulls data from the database to display on the screen. So the api is that transaction that happens behind the screen (no one sees it happen). Hope this helps, it's the best I can explain."
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o2eou5 | Why are planes grounded when there is fog but they can fly through fog and clouds. | I dont understand when they have control towers and such advanced technology why fog can ground planes. Not much is done by eyesight now surely? | Technology | explainlikeimfive | {
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"Flying and landing are not the same thing. Flying involves working hard to stay far away anything. In that system, a cloud or fog isn't a problem. Alas landing can't work without touching the ground, gently. That gentile touching is hard to do when you can't see the ground.",
"Pilots need visibility to maneuver the airport. They need to be able to see beacons, runway marking, airport support vehicles etc. The tower needs to be able to see plane activity on the runways.",
"Instrument rated pilot here. It is possible to land a plane in “zero zero” conditions, meaning clouds are to the ground and you can’t see anything ahead of you. Doing so requires the aircraft and runway to have special equipment and the aircrew to have special training. Check out Cat III Autoland, there are plenty of videos on YouTube. Any instrument approach will have “minimums”, a required vertical visibility to land. This is typically 200 feet, or 100 feet with certain lighting systems. Approaches are flown with GPS, ground based radio beacons (instrument landing system), or a combination of the two (GLS). Visual approaches are quite common in good weather. Planes can land closer together in visual conditions.",
"It depends on who is flying. Most commercial airliners/pilots are rated for instrument-flight, meaning they can fly in adverse weather conditions like fog or night-time. But for private or charter planes/pilots, they may not be rated for that, so they can only fly when it's clear skies. Additionally, there is increased risk. Take off and landing are the most dangerous times in a flight. A plane in flight can't really do that much to get out of clouds/fog; additionally, there's not much else to run into at 30,000 ft above sea level. But, near the ground, there are a lot more hazards, so it's a lot safer to wait for clear(er) weather before taking off to minimize the risks during the already-riskiest part of the flight."
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o2ko3b | What does 'Legitimate Interest' mean/include on cookie banners? | Is there an agreed definition of what can be considered a site's 'legitimate interest', and if yes, what is it? Or is it just the wild west, i.e. 'this is my site and I say it's in my legitimate interest to maximise my income by tracking and selling your data in exchange for my content'? | Technology | explainlikeimfive | {
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"To give an over-simplified explanation that its appropriate for this subreddit: \"Legitimate interests\" are defined as part of the GDPR (the General Data Protection Regulation that governs data privacy throughout Europe), and they are one of the reasons why a business or website might collect personal data. Sometimes \"consent\" is requested, but it can sometimes be difficult (or really annoying for everyone) to try to get consent for every single thing. So, \"legitimate interests\" are those reasons why a business might collect personal data where you might reasonably expect a business to need that information. For example, a business that sells physical goods through their online store will need your name and delivery address (and possibly phone number and email) so that they can send your purchase to you - the business might just decide to collect these details as part of their \"legitimate interests\" rather than asking for your consent to let them use these details, because what if you don't consent to providing your delivery address, or withdraw your consent to them storing your name (which legally they must for six years, as part of their accounting obligations)? Therefore, a business or website doesn't need to ask for your consent to collect personal data for these \"legitimate interests\", but they do still need to ask for your consent to use your personal data for other things such as adding your email address to a mailing list for marketing. Of course, it's a bit more complicated than that, but hopefully this will help to simplify and explain things for you.",
"It's self-defined, but obviously if someone wished to challenge such a wide interpretation of legitimate interest as you've given, they could sue the website. It would then be up to the Courts to make a final ruling.",
"Wild West, they can choose whatever definition they want - just say no to everything especially when Apple asks if an app can track you. They’ve given that option so you can protect yourself so do it Source: I’m a dev, I work with cookies Slightly off topic because this isn’t cookies specifically but… Used to work for a larger retailer and the amount of data they collected was crazy - most of it unused but “might be useful one day”. They used to have “data warehouses” (huge servers) to store it all but that became too cumbersome so they implemented “data lakes” (massive storage) instead. Essentially all that data just gets poured into a “lake” and just collected and collected. Then one day when you need to target a specific subset of people, you run a query and grab whatever data you need to push ads/products to them Now that’s just one company that only wants to sell you things… push that out to multiple governments/bad actors across the world with much bigger resources and a potentially worse intent (either now or in the future) and you can imagine the scary consequences and/or dystopian nightmare we could one day find ourselves in… Limit the amount of day you give away wherever possible. Get a VPN (recommendation: Proton) and use Duck Duck Go (browser and search), close down any old accounts you think of and no longer need etc etc etc"
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o2m83j | How can videogames render many frames of high-quality 3D graphics every second, but rendering just one image in a 3D software like Blender can take hours? | Technology | explainlikeimfive | {
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"Video games cheat, blender doesn't. As you said, video games need to render their world in just 0.03 seconds. That doesn't leave a lot of room for fancy tricks and detailed calculations. If you really stop and look at a video game world you'll quickly notice the \"high-quality\" image has a lot of things that are wrong. Video game lighting usually is super simple. Shadows tend to be wrong, not match the light sources (or just the strongest light source), or be prebaked all together for things in the environment that do not move. Textures and models that are far away are usually just crude approximations of their close-up versions. Reflections typically are crude or missing entirely. Everything not physically on screen is not rendered. Cloth, grass, hair, and everything that has many very detailed things in groups will often move as uniform clumps instead of bothering to render each hair with accurate physics, and so on and so forth. Blender will usually follow whatever setting it is set to, but by default it will try to make whatever it is rendering as accurate and realistic as possible. Every ray of every light source is mapped and ray-traced, every texture is taken in to account, every shadow is factored in from every light source, reflections actually work correctly for reflected surfaces, everything that exists in the scene is rendered because it may affect the things on screen as well as off. Blender has the time to do rendering properly, whereas video games do not, and thus cut every corner they can think of.",
"Video games use a bunch of tricks to speed things up. For instance, not all shadows are dynamic. Many are \"baked\" into the texture they're falling onto beforehand and that process takes hours during development. But when you see it it just loads said shadow as an image texture and doesn't have to do a bunch of dynamic calculations. I don't know the full answer here, I'm sure there's more, but part of it is that it does actually take hours for some things, they just make sure those hours are spent behind the scenes lol."
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o2mdny | when a video you're streaming is buffering, why does it load faster when you rewind a little as opposed to just letting it buffer on its own? | Technology | explainlikeimfive | {
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"Id imagine 1 of 2 things is happening. 1. Your restarting the buffer/download and it could be getting a better connection the second time. 2. Its an illusion and its not faster you’ve just wasted enough time rewinding/waiting for it to buffer that when you watch the thing the content is now loaded far enough that watching the movie won’t catch up.",
"Sometimes, computers get stuck. Things can glitch, and maybe it gets caught in a loop that it's never going to exit. The rewind forces it to try again, and hopefully it'll do the right thing. Humans do this too. Ever tried to tell someone something, realising your just spouting nonsense, and then you pause and start again? Same idea."
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o2us80 | What is a travel router and how does it work? | I hear about people using travel routers to connect devices to hotel wifi or in dorm rooms. What is a travel router and what does it do differently than just connecting to the provided wifi? TIA! | Technology | explainlikeimfive | {
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"As someone that has used these here are the scenarios for where I bring my own router and its configuration: Configuration: * The Router can connect to an available WiFi network or connect to a wired network. * It then makes a VPN connection back to my office * It then provides its own private \"to me\" wifi network and/or wired network where the network is secured through the VPN. & #x200B; The use cases: * Restrictive network access in the hotel. This is worst in Vegas, probably bad in San Francisco/New York/Seattle Particularly during conferences, hotels will have \"Free wifi\". that \"Free\" is with the compulsory \"amenity charge\" that grants you access to a fitness facility, business office, and room wifi. However, it is very often limited to 2 devices/room. If you are going to Vegas to gamble, well, fine, that probably works. But going to a technology conference? We will have 3 people in the room, each will have a minimum of 3 devices (phone, computer, tablets, whatever we are evaluating from the show, or working on for our demonstrations, or maybe some analytics devices for determining show success, etc.) Anyhow, we can expect to need 12 devices/room to be operating. At $15/day/device for a typical \"amenity\" change, that's a lot of cell phones going to the gym that can be avoided by using a single \"travel router\" connection, now our room can tunnel all that data securely out. & #x200B; * Travel to locations where your data can be expected to be scraped, spied upon, or filtered/censored From the above, this should be obvious. But maybe you aren't thinking about it when you go into that meeting room in a customer or supplier's building. They have the whiteboard setup, or the first slide of the powerpoint is the WiFi network access information. You have been traveling for 20 hours and want to get a quick message back to the kids so you connect and do that facetime meeting or whatevs. Then halfway through the meeting, you check your email… If instead you just connect your travel router to this network you can be sure your communications are a bit more secured.",
"I have one that I flashed DD-WRT on that runs a constant VPN so all my devices run through that. Hotel WiFi’s are notoriously unsafe."
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o2wngy | What do people mean when they say you don't actually own the games you buy digitally? | I guess this comes under both technology and economics. But yeah I don't get it. You pay money for a game, you now own that game. That's how a transaction works. If I don't own it what on earth did I pay all that money for? How can companies get away with this? | Technology | explainlikeimfive | {
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"You own a license to play said game. You don’t own a copy of the game to do what you like with it.",
"Imagine you wake up tomorrow and Steam says, “we made enough money, we quit, Steam has been permanently disabled.” (Obviously it wouldn’t happen quite like that, but still.) You don’t have a way to play the games you paid for. You don’t have a physical copy of it that you can just play without support from an outside source. You are relying on the service to continue existing. If you buy a paper book, you own it. Nobody can stop you from using it. But if Amazon wanted to, they could brick your kindle remotely and hold your books hostage for more money or a subscription service or something else. That’s really what people mean when they say you don’t own digital media; you’re paying for access to it and must use it within the framework of the digital supplier.",
"No, that's not how transactions work. For example, you pay to see a movie, you don't own that movie. You've paid for the right to see it once. You walk into an apartment and pay the landlord for an apartment, you don't own the apartment, you're renting it. It used to be you could go to the game store, buy the game and it was yours. Now (and especially with streaming and digital games such as you get with Steam) there are a whole hosts of terms and conditions you are agreeing to when you download the game. For a non-game example, I used to have a copy of a drafting software. I could load it up and use it whenever I wanted. It was, for all intents and purposes, mine. Well, it soon became out of date so I looked into purchasing a new version. Except the company that made it wasn't selling a new version, they were selling a license to use the new version for a monthly cost. And they get away with it because that's how things work. It's their software and they can sell, rent, and distribute it however they want. You aren't entitled to be sold something if they don't want to sell it to you. And when you see that big block of text and click \"I agree\" you are, in fact, agreeing to the terms and conditions under which you are accepting the software, which may include the fact that they are only giving you permission to use or play it, not that you outright own it.",
"I would also add that you don’t “own” something you buy on physical media either. You own the disc, box and manual but don’t own the contents of the disc. Digital licensing is basically the same thing other than the absence of the physical items.",
"You have a license to play the game, you don't own a copy of said game. This is how almost any software is distributed these days. Ita buried in the terms of service for the game and digital store front you use. You are allowed to play the game, but not duplicate, alter or otherwise do anything other than what the developers allow. If you owned the game, you are free to do whatever the hell you want with your own copy.",
"It's similar to a permanent rent than ownership. Imagine that you rent a home but only pay for it once, no monthly fee. You sign the usual contract and you can move right in. Most of the time it feels like it's your own home. You live there, you have your own keys, you can lock it, you can buy new furniture etc. But you're not allowed to resell it, remodel it, change the locks without notifying your landlord or rent it out yourself. You also don't own anything that was already in the home when you moved in, and you have to preserve them in good condition. The landlord can also evict you at any time, but it happens very rarely. If you break the rules you've broken the contract and the landlord can evict and sue you. Similarly, when you buy the game, digitally or physically, you don't really own it. You can't resell it, you can't dissect it and use assets from it for your own projects, or make derivative works. (Sometimes you can get away with it but officially most of these are not allowed) You can, however, play it as the developers or publishers intended. The only difference between digital games and physical disks is that they can't take your disk away."
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o32z8v | On the personnel list of music albums, “mixing”, “engineering” and “production” are listed as 3 different categories. What’s the difference between them? | Technology | explainlikeimfive | {
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"The producer works on the music itself (arrangement, lyrics, etc.), the engineer records, and the mixer mixes the recorded tracks. If a programmer is mentioned they are involved with sequencing and synthesis usually."
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o3b6g0 | why is asphalt used on roads ? | Technology | explainlikeimfive | {
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"It's cheap (it's essentially just the crap leftover from refining oil) and much easier to apply than concrete.",
"Predominantly because it gives a very smooth finish. That's going to be quiter for the vehicles but also mean less repairs to the road. It also has the durability required and is relatively easy to lay",
"It's got grip so tires have good purchase on it. It can withstand a good amount of wear and tear before repairs are needed, it doesn't change consistency too much in high or low temperatures. It's weatherproof, it's super cheap. It's relatively safe to drive on even when wet. There are companies who are out there trying to sell \"smart roads\" which are modular and made of plastic panels which supposedly make repairs quicker but actually because it's plastic, repairs are needed almost daily compared to asphalt which needs repairing every few years. It will be a very long time before we move away from asphalt as a road surface",
"Awesome, one of the things I studied and do work with on the daily. Asphalt binder is relatively cheap as compared to cement. It is the excess “sludge” from refining crude oil while cement is made from burning multiple ingredients at 2000-3000 degrees F. Asphalt has a Viscoelastic property to it. Which means that as temperature changes, so does it viscosity, and elastic response to loads. When it’s cold outside, it is tougher and won’t flex as much. When it’s hot outside it will flex more. There are hundreds of not thousands of different types of asphalt binders. They are categorized by a method developed by Superpave in the 1990s. In Alabama they use a Performance Grade (PG) 67-22. The 67 is the high temp range in Celsius of the binder for it to not rut to failure. The -22 is the low temp range for it not to be too brittle at cold temps and crack. This PG can change based on the binder source. Colder states like minnesota might use a 58-28 to account for lower high temps and lower cold temps. If the right grade of asphalt is selected then you can prevent rutting and cracking. Rutting is when the road is too soft or the load from traffic is too high and the wheel paths sink down. This typically happens at intersections when traffic sits for longer periods of time. Cracking is when the road is not elastic enough to “relax” under loads and has to crack to relieve stress. Asphalt pavement can be paved in one continuous stretch, while concrete must have joints every 15-20 feet to allow the segment to expand and contract with temperature. It also can be driven on relatively quickly as compared to concrete which may need 7-14 days before trafficking. If the road is paved with a strong granular or asphalt base, only the top 2 inches needs to be replaced every 15 years or so. Unless cracking/rutting is bad from poor designing or unexpected truck loads. Asphalt pavement is recycled all the time. It’s relatively used in new roads taking up 10-40 percent of the mix depending on the state and project. Ask me anything else below this and I’ll get to it. Sorry for any typos!!",
"Its cheap, its almost 100% recycled, it gives good grip on the tires while providing a water barrier. Its not hard and stiff so it can adapt to changes without cracking."
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o3gyuz | What makes thermal wear warm? Why is often polyester made? | Technology | explainlikeimfive | {
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"Good thermal wear works by a combination of capturing and holding the body heat while transporting moisture towards the outside.",
"It traps a lot of air. Air is a very bad conductor of heat i.e. a good insulator. Generally thermal insulation is all about trapping as much air as possible, using as little material as possible. That’s why down is such a great material for winter clothing. It’s very light, yet expands to considerable size. The advantage of “synthetic” fibres like polyester is that they don’t clump up when wet and don’t trap a lot of water. But for insulation it’s generally a good idea to have some wool (or down).",
"A good thermal layer wicks the sweat away from your body keeping you dry, having this layer is extremely important especially if you do any winter related sports; if you were to wear a cotton shirt and go say snowshoeing the cotton would absorb all your body moisture and sweat eventually once you open your over coat that cold damp shirt will freeze. Not sure what makes polyester the best but I’m guessing because it’s a man made fabric it was designed for that purpose? Also sometimes you’ll see a thermal lining inside jackets it looks like a shiny metal layer of fabric it bounces heat back towards you so you’re always warm"
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o3hkcc | Why do the televisions in the store always have amazing pictures but when you get home and pop in your favorite movie...? | Shopping for a new TV, this is mild infuriating. | Technology | explainlikeimfive | {
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"TVs typically need to be calibrated after you pull them out of the box. They look great in the store because they are specifically calibrated to make the demo video used to show off the TV look as good as possible. However, those demos don't translate to every day TV, movies, etc. I usually Google the make/model of my TV plus the key word \"calibration\". You will see several professional review sites that will usually share the recommended calibrations or calibrations they used to test. Now, if multiple sites are saying the same thing for a certain setting, that's what you do. If they vary on another setting, go with the one you like the most. This will give your TV a good baseline configuration and then you can make adjustments from there. Hope this helps!"
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o3jml9 | I’ve always understood that computers work in binary. But programming languages use letters, numbers, symbols, and punctuation. How does the program get translated in binary that the computer understands? | Technology | explainlikeimfive | {
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"Most of the answers here are correct, but it's also important to note that all the letters, numbers and symbols you enter with your keyboard are also in binary. Each character is represented by a number, for example the uppercase letters A-Z are represented as the numbers 65-90. These in turn are represented in binary.",
"The answer actually depends on what programming language you're using. In compiled languages like Java and C/C++, the code gets transformed into a computer runnable executable after you write it, which consists of binary instructions. This transformation is a process called \"compilation\". By far the biggest non compiled language in use today is Python. In python, the code actually gets turned into binary on the fly as you run it. Quick edit for clarification: A compiler can mean multiple things. If someone is talking about a Java compiler, they are generally referring to the entire pipeline that converts Java into machine code. However, if someone is talking about the compiler stage, they are probably referring to the individual part of compilation called \"the compiler\", which actually is not the part that creates binary.",
"Letters are converted to binary using some [character encoding]( URL_4 ) . This is a kind of convention that says how a character is written in binary. This has changed through the time. Nowadays many systems use [UTF-8]( URL_0 ) Integer numbers are also converted using different methods. The most popular is [Two's complement]( URL_2 ) . With 2 sub-variants [Little-endian and Big-endian]( URL_1 ) . Real numbers are now mostly converted using one of the [IEEE 754]( URL_3 ) floating point formats",
"It's all binary in reality. The letter 'A' in this message is simply character #65, which is `1000001` in binary. And in old computers there's literally a table where characters are drawn, again in binary. With a 1 where a black pixel would go, and a 0 where the background would be. Even when dealing with compilers you're taking one kind of binary data in, and producing another kind of binary on the output.",
"It would be fun to do a deep dive on computer languages as an ELI5. Let's give it a try! Computers, at their lowest level, are electrical circuits. Complex ones. Very very complex ones. But what's neat is that we've made these circuits into interesting patterns where we can load a 'program' into it and it performs math and logic and interacts with inputs (keyboard, mouse, internet, etc) and outputs (monitor, speakers, internet, etc). Since everything is an electric circuit, everything is stored and processed as 'binary'- 1s and 0s, meaning 'on' or 'off'. Electricity flows or doesn't flow. (Often it's 'high voltage' vs 'low voltage' but the idea is the same). That is where the idea that programs are binary comes from. Everything on a computer is binary! And when we load a program onto the computer, we're just turning circuits on and off very quickly in specific patterns so that the computer (the processor) does the things we want it to do. But it turns out that writing programs in binary by hand is really really hard. And we programmers are, usually, the laziest people you will meet. Do you know what happens when you give a lazy person a tedious and difficult task? We find ways to make it easier. And so we came up with very slightly higher level 'languages'. Instead of raw binary, we would make 'words' that represent specific binary patterns. Move this bit of data into this CPU register (a memory spot)! Run CPU operation ADD! It made things really a lot easier. Except then we started to have bigger, more powerful computers and we needed to make bigger, more complicated programs. Lazy programmers to the rescue- we made higher level languages that map more English-like words down to Assembly language and binary. This pattern keeps repeating. Programming languages today are often very readable, sometimes very close to being English. There's a whole field of study in computer science of how to make the best computer languages, and how to make them compile down into the fastest, most efficient binary programs. Source: Bachelors of Computer Science, plus ten years as a software developer"
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o3krqt | - why is airplane internet so unstable? | Technology | explainlikeimfive | {
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"Oh wow. This is my job! So imagine every piece of information goes through hoops to get to the server and back to you. On an airplane when you fly above the clouds the information must go through a satellite, and the more hoops there is to jump the more possibilities for something to go wrong."
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o3n011 | What’s the difference between high quality and low quality speakers? What’s actually happening that causes one speaker to sound super crisp while another speaker sounds muffled? | Technology | explainlikeimfive | {
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"The main measurable things are frequency response, distortion, resonances, and dispersion. Bad speakers have a poor frequency response so certain frequencies are louder than intended, such as boomy bass or high pitch noises. This is very hard to achieve and requires digital processing/equalization to be near-perfect. They also have high distortion. This would be like if only bass is supposed to be playing but instead you also get higher frequency noise that shouldn’t be there at all. Resonances cause very specific frequencies to be very loud and also they keep ringing even when the sound should have stopped playing. Finally, speakers should emit sound in a fairly even distribution in front of the speaker (this is very simplified) so things sound about the same whether you are sitting directly in front of the speaker or to the right/left/above/below it. Bad speakers typically don’t do this well.",
"Acoustic engineers can tell you the answer is not simple, and I ain't even one of those. The entire system works together to produce sound. The material, size, and angle of the cone; the weight and strength of the magnet; and the size, structure, and resonant frequencies of the cabinet (among other things) all play a role in the overall dynamics. You could have a perfect cabinet for one cone, and it could sound either bright or muffled with a different cone, ect. tl;dr i dont think this can be explained to a 5 year old."
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o3s2i6 | If all noise cancelling headphones do is reverse the soundwaves coming into them in order to ‘cancel’ the background noise, why can’t they cancel a sine wave completely? | Technology | explainlikeimfive | {
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"They can. But only at very specific spots and, since your ears capture sound over an area, they can't completely make you not hear it. If you have a pure sine wave signal (a pure tone) and broadcast the exact opposite, you will indeed cancel to exactly zero wherever the loudness (amplitude) and alignement (phase) of the reversed wave exactly opposes the incoming wave. Assuming that the cancelling signal is louder than the incoming signal, this will always happen \\*somewhere\\*. But it'll be a very small region. Your eardrum is a whole area so you can't cancel the incoming signal across your whole ear, so some will get through, so you'll always hear some of it. Edit:typo",
"In addition to the great explanations already shared, when you hear a sine wave you’re hearing the wave, plus all the slight echos from the environment. Your brain does a remarkable job cleaning it all up for you, while using those echoes and the folds of your ears to interpret the direction the sound might be coming from. (As an aside, consider this: with both ears you can imagine how your brain could figure out where something is on the horizontal axis, based on comparing the left and right input. But your brain is also able to guess approximately where on the vertical axis a sound is coming from. With your eyes closed, if there is a click straight ahead of you, you can tell if it’s up high or down low.) So, what hits your eardrum is never a simple sine wave. The simple sine wave can be canceled but you still hear all the slight echoes.",
"Because there is always some small distance between where the outside sound is sensed by some sort of microphone and where it needs to be cancelled, ie at the entrance to your ear canal. That introduces a small time discrepancy. The effect of that varies with frequency of the sound in relation to the length if time for one cycle of the sine wave.",
"Because they're using miniaturized components manufactured to a specific cost and not lab-grade equipment in a tightly controlled environment. What they can do is pretty amazing but all of the variables they cannot control makes the situation difficult. Noise bleed via physical transmission(making the headphones vibrate or noise passing through the headphones), air leaks between your ears and the headphones, physical conduction of sound (feeling the sound due to the pressure waves). They're also extremely limited in amplification and to offset a sound you have to produce the opposite off that wave in frequency(pitch) as well as amplitude(volume). If it's not the same amplitude, you'll simply get an attenuation (lower volume)",
"To completely cancel the sound the reversal would have to be instantaneous, but there is a finite but non-zero lag between the sound being picked up on a microphone and when it goes through the circuits reversed."
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o3xqn1 | targeted marketing | Have you ever been talking to someone about a specific product or food and then the next day, someone else is starting to see advertising on their phones for that very thing? I was recently talking to my husband about a German sausage shop called the Sausage Man for a BBQ and then the next day, my brother-in-law started seeing ads even though he wasn’t even in the conversation but sat in the same room. How does that work? | Technology | explainlikeimfive | {
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"Sometimes it is coincidence! But technically, the apps on the devices will have pre-configured rules which will use phrases heard in this case to target advertisements or offers or rewards for you. This is a very high level explanation. In reality, it is complicated, businesses configure weighting for lots of different attributes and other factors to be able to give you the most useful and applicable advertisement or offer in front of you. YouTube, I am sure will be doing the same for their recommendations. So it's the phrases that matter, not the entire conversation. So for example, if the rules are configured for \"UFOs\" then even if you said something about sausages for a long time but uttered the word UFO maybe a couple of times, it might be sufficient to trigger those recommendations. It's not super easy to configure very effective rules, that's why they add machine learning behind it, which will come up with the correct weighting based on statistics rather than a hunch.",
"On the one hand it's confirmation bias. If you're talking about a product then you're primed to view it. So you're just noticing a relevant ad. On the other hand, if you actually search for the same product or navigate to a page that sells that product then advertisements learn your preference for a product. \"The Algorithm\" (TA) goes a step further, and begins predicting other products that are similar to the one you searched for. Let's say you search baby diapers, so TA will guess you probably will need formula, wipes, baby powder, and other relevant baby products. So it seems like advertisements are being targeted to you. TA goes yet another step further by identifying your browsing profile as a whole and comparing it to other profiles. So you don't even have to be planning a child, but if you share enough trends with other people that are planning a child, you might get a few ads regarding diapers even if you don't have a kid. In this case the advertisement failed, but this logic is applied across your entire profile. On the third hand, there are some apps that do passively report audio and feed you ads that are relevant to the recordings. I remember Facebook and Facebook Messenger caught a lot of flak for this a few years back. I'm sure more apps or smartphones may be doing the same thing and have it hidden somewhere in their Terms of Service. When you take all three of these together in tandem, TA can almost appear clairvoyant in how it selects advertisements.",
"A lot of that is just coincidence. We see so many ads that most of them fly by without us consciously registering them. Your brother-in-law could have seen the ad before, but didn’t pay attention until your conversation. (This is especially likely if the shop is in your area, since many ads are targeted by location)."
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o400vn | How does gpu and cpu work by comparing them to a different object to explain their similar functions | What I mean is that if you can think of an object to compare them to and explain their function so it will be easier for me to understand. Like comparing a chest's size to a phone's storage and how much a washing machine can wash clothes comparing to RAM. Despite learning about CPU's and GPU's description, I still can't understand how they work specifically | Technology | explainlikeimfive | {
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"A cpu is like a university professor and a GPU I’d like a room of 1000 children. The professor can solve difficult problems but he can only really work on a small number of things at a time. The room full of children can solve lots of simple problems very quickly, in the case of a GPU normally those problems are simple arithmetic.",
"The Mythbusters crew did a demonstration of this for Nvidia a few years back. They built a \"CPU\" using a paintball gun mounted on a servo gimbal so they could aim each shot perfectly and paint complex images on a canvas. Then they built a \"GPU\" which were just a bunch of tubes all in parallel all with their own paint ball but the air hoses all went to one big trigger and there were no servo gimbal at all. And using this they were able to paint an entire picture all at once with just one trigger pull. This was a good demonstration because each core in a CPU is a lot more capable and is able to act on its own individual instruction thread. However a GPU have hooked up a lot of much simpler cores that shares as much as they can and all act on the same instructions together (but on different data).",
"I suggest you look at [this]( URL_0 ). Keep in mind that Leonardo 1.0(see vid to understand what I mean) is more \"dynamic\" in the sense that it can move around, be reprogrammed way more easily etc., while Leonardo 2.0 can only do one thing: put paint on a surface as fast as possible. Obviously it's much more nuanced than this, but you asked for an analogy, so here it is."
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o43wgg | What is the difference between 5.1, 7.1 and 3D audio and which is better? | I see alot of these terms being used when selling headets and also used by game developers, but never really knew the difference between them. | Technology | explainlikeimfive | {
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"It all pretty much only describes your sound setup and therefor what kind of sound processing you want to take place. Ignoring 3D for a second cause honestly I don't know much about it. But 5.1 and 7.1 is pretty much the same thing with it describing your speaker setup. The .1 is the subwoofer in both setups. A 5.1 Would have a center front, left and right speaker + left and right from behind. And a subwoofer. A 7.1 sound system is pretty identical with speaker directly to your sides as well. 3D sound would in addition have sound coming from above and below. 3D sound as a concept means sound can come from any direction really, so it's generally achieved by fooling your brain into thinking sound comes from one direction or another and isn't \"true\" sound coming from all directions.",
"The problem you're going to have is trying to define what better means. I used to be really big on surround sound but for the past few years I've found it really distracting. So a good 2.1 system that's cheap is going to be better for me than a 5.1 or 7.1 system no matter how amazing. If you're a professional gamer and want to hear a gunshot coming from behind you so that you can respond then yeah maybe it is better. But that probably depends a fair bit on what games you're playing. I would also guess (though I'm no sound engineer), that a headset that kicks ass at left and right (and that's it), is going to do a lot better job for sound quality than a headset that is trying to bend and play with sound waves to make sound appear to be coming from different directions. Kind of like how a cake is going to taste better if it isn't coated in icing to try and make it look like a unicorn jumping over a rainbow. Which is the better cake? Well if you care about taste then plain is the way to go. If you care about how it looks then maybe the unicorn jumping cake is better.",
"> when selling headets In the context of headsets, there is no significant difference between those terms, and which headset is better has little or no relation to which one is used and is partially subjective. When selling surround sound speaker setups, both 5.1 and 7.1 refers to the number of speakers you're getting: the number before the . is the number of mid and high frequency speakers you'll place around the room while the number after is the number of subwoofers. \"3D audio\" is another term that doesn't have a \"hard\" meaning, but it could be used to describe the software solutions some games - especially VR games - use for giving you vertical audio cues such as \"shoulder reverb\" when the source of the audio is above you. Not that I'm actually certain any VR games do that, could be it's just my subconciousness keeping track of terrain and noticing stuff out of my peripheral vision."
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o49lwf | If HDR is just a monitor having better contrast, why do games/videos have to specifically support it? | I'd imagine the game's graphics engine for example just saying which areas are bright and which areas are dark and the monitor doing it's best to display those differences, with HDR Monitors just being better at it. Where am I wrong? Like why can a monitors contrast get better and better and still support the same games, but once it apparently passes a specific barrier it stops supporting certain games with that contrast? | Technology | explainlikeimfive | {
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"The recorded and transmitted video data has to conform to a specific set of standards that constrain the possible quality you can achieve. To get HDR, you need to use a suitable standard such as Dolby Video, which adds more precision to each pixel than would be possible in normal (non-HDR) video. If you really want to see an example, the wikipedia HDR page gives some detail as to the specific codecs used: URL_0"
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o4bb9y | how does the storage and RAM memory limitations work | Manufacturers can't build a 100TB flash drive or a 256GB RAM memory for desktop computers? Why popular modern computers only have 1TB of storage and 16gb of RAM? | Technology | explainlikeimfive | {
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"Cost. There are limited usability with those kind of specifications, however with special use cases they do have those kind of specifications (machine learning, high performance computing etc.). You are also limited by what the cpu can address, where consumer hardware doesn’t have the number of addressable ram and pcie lanes like higher end cpus have.",
"> Manufacturers can't build a 100TB flash drive or a 256GB RAM memory for desktop computers They can, but [you're not]( URL_1 ) in the [market for it]( URL_0 ) Consumer goods are driven almost entirely by cost. There are generally things 3-4 tiers up that are pushing the limits of our technical capabilities but are ludicrously expensive. Your average person makes their purchasing decision off of price. They're not going to pay 8x more for 2x the capacity unless there is a really compelling reason for it like they're actually building a server or a workstation that needs it General desktop hardware is the stuff at the happy point of the price and performance lines where you get pretty good performance for a pretty good price and this is because they can use parts that aren't pushing the limits of the processes and have pretty good yields (aka lower per piece costs) than the maximum performance ones where over half might not meet the requirements",
"You most certainly could build a 100TB flash drive, or 256GB RAM for consumer PCs, it's just that the flash drive would be way too big physically to be useful and have more storage than anyone would need, and not many people would need 256GB of RAM. It's a supply and demand thing. Hardly anyone wants 256GB of RAM because it's simply too much and would cost too much, it wouldn't sell for consumers. A 100TB flash drive would be way too expensive to manufacture and would be really big physically, for something that most people won't need because it's just too much storage. Popular computers have 1TB storage and 16GB of RAM because those are both a sweet spot of cost/performance. Most people don't need more than that, and those that do need more than that do have consumer parts to buy instead."
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o4da8h | Can the internet run out of space? | If we keep creating new websites and never stop uploading new content to the internet, there must be some sort of upper limit or maximum load. What is that amount, and how will we know when we’ve reached it? Or is the internet infinite? | Technology | explainlikeimfive | {
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"I might be wrong but iirc, the “internet” is just a network that connects computers. So technically each website or video you see is actually saved on a server computer at a physical location, just like you would save photos on your phone or laptop. When you go to the website, you send a request to access it and to see the video and the server sends the corresponding data to show you what you requested. So the amount of data the “internet” can hold is theoretically infinite if you just keep adding computer to the network and expanding the storage of said computers",
"The internet isn't a unified entity. It is just a bunch of computers linked together. As long as people buy new computers or add hard drives when their specific website starts running out of space you can keep going.",
"As others have stated, the internet is merely a connected network of servers, so in the sense of will the internet run out of storage space, no it won't. Looking at your question from a technical perspective: yes. The internet has already run out numbers to assign to those servers that host your websites and to those devices accessing the internet. Each server or device needs a number to access the internet, an IP address. Those numbers reside in a protocol called IPv4. We no longer have any free IPv4 addresses. To solve this problem, we have adopted and are currently using another protocol called IPv6. IPv6 significantly increases the amount of IP addresses we can generate, but it still has a maximum amount of numbers. So in theory, we could once again run out of space on the internet."
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o4jc9l | How can a poorly coded videogame "brick" your computer or console? | Technology | explainlikeimfive | {
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"I'm not sure this is even possible. The only ways I can see software bricking a system is if the software has OS or kernel-level permissions. Which video games never do. Pretty much any software that tries to get those permissions are easily recognizable as malware. More commonly, systems get bricked because of an oversight in the system's internal design. The Xbox red ring, the solid blue light on ps4, etc. A video game might push a console to its limits, and due to a faulty capacitor on the PCB for example, some components get more power than they were designed to handle and they get fried. All because the manufacturer cheaped out on capacitors and got them from a shady Chinese company. There are many other ways a system can be bricked, but it's always due to an error or oversight in the manufacturing of the system. A well-made system can't generally be bricked by using it for its intended purpose. Unless the user messes around in the BIOS and changes things they shouldn't. More often than not, the user causes it. Edited to add: The worst a poorly coded video game by itself can do to a system is crash and become unplayable. Computers have failsafes in place to ensure too much power isn't drawn, temperatures aren't too high, and big errors (like a blue screen) simply mandate a restart to flush the memory. It's very hard to brick a system nowadays if you're not a tinkerer. Another edit: People seem to not understand what \"bricking\" a system means. A bricked system is effectively useless to the point where it's only \"as useful as a brick.\" A system that can be fixed with a simple reinstall of an OS is not bricked. A bricked system would require extensive software patching and/or hardware replacing to get running again, often requiring a professional. A motherboard with bent pins in the processor receptacle is an example. A BIOS update with a bug that inadvertently stops recognizing hardware during boot cycle is another. Hell, it could mean you submerged the whole darn thing in water while it was powered on. That's a bricked system.",
"This used to happen more in older systems and isn't as common these days. When it does happen, the actual cause is usually pretty different in each case. Systems usually run in 2 main parts: the Operating System (OS) and the software. The OS's job is to run the software, and manage things about the software such as memory and file system access EX: The software asks the OS `\"Hey, can I save a file?\"` and the OS responds with `\"Sure, tell me where and give me the data and I'll put it there for you.\"` If the software asks to put a file somewhere it shouldn't, or access memory addresses it shouldn't have access too, then it's the OS's job to say `\"Hey wait a minute, you shouldn't be doing that,\"` and stop the software either by gently tapping it on the shoulder and reminding it so it can correct itself, or straight up nuking it if it really has to. Sometimes though this doesn't work the way we want it too. Software (whether the product software or the OS) is incredibly complex, and it's impossible to foresee and plan for all the ways the two can interact with each-other. Sometimes software writes to a place it shouldn't be able to on accident and the OS doesn't catch it, sometimes it modifies memory it shouldn't and the OS then interacts with that modified memory and unexpected things happen, and sometimes both work fine but the hardware they were interacting with got confused and started sending unexpected data. There are practically infinite ways these systems can mess up. For example say a piece of software accidentally writes to an incorrect spot in memory but the OS doesn't catch it. The OS then writes this modified memory to a file on disk for use when booting the system (not knowing it's been incorrectly modified). When the OS tries to read the borked file next time it starts up it might be unable to boot since the programmers of the OS never intended the file to be modified by something other than the OS itself and it now contains a bunch of gibberish in place of important instructions.",
"The chance of a game actually \"bricking\" your computer is very low. On most consoles, games are heavily sandboxed and dont have the priviliges to directly cause permanent damage to the console, unless its something like runnings so poorly it physically overheats a specific component. Games can most definetly crash due to unhandled errors in the code. On PCs, I guess there could be a very small chance some filesystem write function accidentally overwrites a system file *somehow*, but the chances of a legitimate game making a device permanenetly unbootable is extremely low.",
"They can't; they can be made to appear to, however. In the hacking world, \"binders\" are programs that look like a normal shortcut or executable but actually run two programs. The first program is usually a trojan horse server or RAT server. The second shortcut is the normal program, steam.exe for example. Often RAT servers will be programmed to send out to a beacon service so that the blackhat on the other end will never be directly connecting to the victim PCs. This can often allow a volatile script that bypasses firewalls and uses admin level to push data out. Because these programs are typically relying on exploits that will eventually be closed...or the program can simply go bad after a change to the OS...or the RAT developer wrote an untraceable server that works for most OS setups but not all...you get the idea. This can often result in the user noticing nothing, and then one day their OS is corrupted and the computer is \"bricked.\" The user thinks the steam.exe is what caused the issue, and no one ever investigates the possibility of a RAT. Source: Former years in the security industry, been following current developments out of interest since then. There was a Defcon Talk about this exact issue. I can talk your ear off about this stuff."
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o4rtj1 | what is rollback in fighting games and how come it makes it feel like there isn’t really any lag? | Technology | explainlikeimfive | {
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"When you play online it takes time for control inputs to get from player A to player B and vice versa. In a rollback scenario, player B's computer is constantly trying to predict what input it will receive from player A and animates the game based on the predicted inputs. When correct, it appears lagless. When incorrect, the game basically skips a small amount to correct the mistake. So for example: Payer A presses X (punch) at time 0.00s Player B's computer predicts player A pressed Y (kick) at time 0.00s. So now player B's computer starts to animate a kick. At time 0.1s B receives the command player A pressed X at time 0.00. Player B's computer \"rolls back\" the game 0.1 seconds, works out what would have happened if a punch was thrown over those 0.1 seconds, and then skips forward again to adjust the game for the actual input. From player B's point of view, half way through a kick, it changed to a punch. However player B was able to press block, which is equally valid on a punch or a kick, so in this case the incorrect cue from the prediction algorithm was still helpful. When lag is low (say 30ms) this isn't noticeable, but when high, the quality of the predictions becomes important and artefacts like teleportation become apparent. To further improve things some games include a small amount of input lag, say 20ms. This lag is always there, and it's always constant so you're used to it. This 20ms input lag gives the game a little window for the game to \"catch up\" in during a rollback event.",
"There are two ways you can write up the netcode for a game. You can either handle the button presses when they were originally pressed, or you can handle them when they get to the central server. Let's say you're starting with the central server timing. This is also referred to as Delay-Based. If you press a button on your screen, until you receive an acknowledgement from the server that the button was pressed, nothing happens. This creates a lag that you have to overcome that just isn't present with in-person gaming, and is going to vary greatly depending on your connection at the time. However, everything you see on your screen is guaranteed to be what actually happens. The other way, handling buttons based on when they were originally pushed, is what is referred to as rollback. Imagine each button press gets sent to the server with a timestamp. Your local game can start playing the actions right away, because it expects that the server will accept that button press at that time. When it gets to the server, it will look at the timestamp of the button press. If it has already done any calculations for any button presses later than that, then it rolls back those button presses, adds the new one, and then replays them, and sends the correction to both clients. This means that you effectively always get your button press at the time you pressed it, without weird lag making it much later than you intended. This also means that, if there is substantial lag, you can see the game stutter as it corrects itself, but if there is very little lag, then everything appears very smooth for both players, making them feel as if it's a local game."
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o4xq3f | What’s the benefit of a seed box in relation to torrenting? | I know how torrenting works, and I guess I know what a seed box is for the most part. But where I’m foggy is exactly why people use them and what their benefit is over not using one. Every explanation I’ve looked up just doesn’t clear that up for some reason. | Technology | explainlikeimfive | {
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"A seed box is an external box that is dedicated to seeding torrent files. They are usually VMs on an external server. People use them because many private torrent trackers require seed to leech ratios, so you need to seed a torrent for longer than you leech (usually at least 2x). You _can_ do this from your home PC, but it would require the PC be on all the time, using your bandwidth, and potentially exposes your IP address to the swarm (which can result in lawsuits). A seedbox resolves both of those concerns"
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o58cry | During a live televised sports match, how do they get the replay footage edited in so quickly? | I’m curious as to how a ref will blow their whistle and get instant replay footage within seconds. Can someone explain this process to me? | Technology | explainlikeimfive | {
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"There's a whole room (or trailer) full of directors, producers, and editors watching dozens or hundreds of feeds simultaneously. They're pretty much constantly cutting highlight shots, different angles of play, etc to be ready when the lead director wants a replay. It's a huge amount of very fast-paced work.",
"There are a few different systems but one of the most widely used ones are made by [EVS]( URL_0 ) [LSM-VIA]( URL_1 ) It’s basically just a multi channel video recorder on steroids with instant access to recorded video w/audio Hope this helps ya.",
"Unrelated: captioning for live broadcasts is also being typed live by someone. Gotta go fast!",
"I design control rooms and their replays systems, and its not quite as bad as one might think. On large shows (if run properly) each replay op will have 4-6 camera inputs to watch, with one or two outputs. Ops that have been working for a long time get used to the rhythm of the sport theyre working. Cameras angles are arranged roughly the same way at every venue (partially cuz I do that too, and obviously we have guidelines), so you know the looks you have available. Like others have mentioned, theres a certain adrenaline rush to having a show go well, and when a production crew is working well together the whole thing feels like a well practiced dance.",
"A lot of the camera feed is inserted into a system that is recording multiple angles and that is fast to create \"events\" with ins and outs. What happens is that someone is watching and every time they see something cool they will create the event, there is usually shortcuts for -3, -5, -10 and -20 seconds, this way a event is created where the start point is on the correspondent time you pressed. After that it's just a matter of knowing if your shot is good when the director calls for the replay, on bigger games and bigger budgets you will have multiple replay operators with multiple cameras, since there is people covering the ball, the off-side line, players near the ball for random stuff, there is the open shot, close shot, slow motion... It's really cool to see it happening, it's a lot of people working together to make it happen and, like a lot of people said here, there is this adrenalin rush that you get on a good show that you can't describe. I'm working with live events for the past 3 years, did eletronic sports for 2 years and I'm on corporate events for the past year, because the market exploded with covid. I love what I do now, but, there is way more adrenalin on any kind of sport coverage.",
"I've only worked on small set-ups/crews but there's usually a replay operator in sports broadcast control rooms. They'll have a rolling recording of a handful of camera angles on a specialized piece of equipment. When the director of the production asks for a replay to show on air, usually of a big event like a goal, they'll ask the replay op to cue up the goal. The replay op will \"jog\" back to the point in the recording where the goal happened (usually just a few seconds to a minute ago), while the replay machine is still recording the camera angle in real time. The director will \"take\" the video signal from the replay machine, while telling the replay op to \"roll\" their footage and put it on air for the viewer at home. It's a lot less editing, in the traditional sense, and a lot more of switching video signals on the fly. Kind of like putting a puzzle together as 5 different people are throwing pieces at you. Sometimes you'll see a heavily edited video as the broadcast is going to commercial break, kind of a highlight reel of the last period, inning, etc. I don't have much experience with that but as far as I can tell, that is done with video editing software (Adobe Premiere, etc.) and played directly out of the computer or done with a much more advanced level of replay equipment.",
"they use a piece of hardware that holds all of the \"streams\" in a sort of memory to be instantly brought back up and spliced in to the broadcast. many places use one by a company called EVS, but there are others as well. when there are longer times, they may edit items in using traditional editing software and then importing that, but in cases where it's nearly instantaneous playback it's usually a hardware solution. in these control rooms multiple people can see all of the angles happening at once and usually it's someone's job to request to the operator specifically what they want to be played back live.",
"This is sort of an ELI5 of how a single replay feed works: Imagine you are walking down a path at a magic zoo. At this zoo, at the end of the path a new animal exhibit will always pop up and the path gets longer, you will never run out of animals to see. You and your friends start walking with a zoo keeper, and as you walk, the keeper puts a flag in the ground in front of every animal exhibit. No matter how far you and your friends walk, you will be able to instantly go back to any animal exhibit by using the flag she put in the ground. Even if your friends keep waking and new animals keep appearing at the end of the path, you can go back to the flags and see an animal you already walked by. When you're done looking at the animal you saw, you can use the flag to catch up to your friends and the zookeeper. It's not perfect, but in this example, your friends are what is happening live at the football game, you are the person watching on TV, and the zookeeper is the EVS(Instant Replay) operator. The video feed is constantly recording what is happening. The EVS operator can go \"back in time\" along the path to an event they made (the flags) and show you the viewer at home a replay. While you are watching the replay, new flags are being made for new replays because the machine is always recording. There is also a producer sitting next to each operator in the truck that keeps notes of what replays are located at which point along the path so that when the director calls for it, it can be found quickly. Like I said, not a perfect example, but nobody else here was really trying to explain it to a 5 years old.",
"I worked for live TV news for a few years in the production room and it was fucking nuts. The answer to your question? There is no one answer haha… just a ton of people playing rough shot with a director putting it all together and piecing together a “show” on the fly.",
"It is a system called EVS. Oddly enough it is a program created for architecture and drafting but that's another story. The EVS machine takes feeds from 4 cameras and has 2 output channels (it can take in more or put out more depending the configuration but 4in 2out is prob most common configuration). There can be as many EVS machines as you want and they all work together on a server called Xserve. When you see something that looks good or is a good play you \"clip\" it but spinning a wheel that moves the playhead forward and back. You mark an in and out point and save the clip. You can then push the clip to the server if it's a really good one. Now, any machine on the serve has access to all the other machines clips and can make a playlist. So, you simply grab all the clips you want (throw in a aux clip with audio at the top of you want it to music) pick the speed you want and transitions you want and when the director calls for it you hit play (or push your speed bar up to the top... Kinda looks like a speed shifter from a boat) This whole process is done by working with the producer or AP and filling whatever is called for in the runsheet. So, it's easy to plan what you want ahead of time and have it ready to go.. but a skilled replay op can have one made in seconds... Like a rollout to commercial. Also there is jobs in the truck called r/o (replay only). They do JUST instant replay. So they clip things and have replays ready but don't make playlists. This helps give the other EVS ops time to make the fancy packs while letting the r/o have whatever just happened at the ready for the director The EVS outputs get named GOLD, SILVER, BLUE, RED and so on. This makes it easy for a director to call out directions on what output is going to air next. Example of EVs chatter: (After a home run) Director \"going to red for the replay. Who has a good look at the bat flip\" r/o1 \"I got it on green\" Director \"ok, green next\" r/o2 \"great picture reaction on blue\" Director \"thank you, blue next then back to gameplay\" EVS \"can you push (send) those clips to my machine of the flip and pitcher react\" ... He then proceeds to put them into his bumper to break and plays it as announcers throw to next commercial break. Hope that lays it out clearly for ya",
"Been saying for a long time that challenge /replays need to be handled by TV crews who have the correct angle and call within 15 seconds 99% of the time",
"honestly, they could just stream every event in a 1 minute delay and it would save them a lot of effort",
"Money, money, and money. Seriously though, production comes down to investing in more people with more advanced machines working more angles to get all those sweet replays. Professional sports are all about revenue from spectators. Even in-person spectators sitting in the stands still watch replays or moments they missed on the big stadium screens. The more they invest in making it exciting, the more spectators they will have and the more cash they will make. It’s a self feeding cycle, really.",
"Basically, you have a device that is recording footage the entire time. It has a single job, which is to remember the last few seconds of an input, and when prompted it plays it back in either in real time or slow motion. The more inputs and footage it can handle, the more expensive it is. My dad uses them when he shoots football, and they're useful when I have to break a shot and run up the field to get in position for the next play. You can actually do this yourself in OBS on your computer for streams, with a little effort.",
"Expensive machines. With turning knobs. Makes the work do much easier. Perhaps you've seen the replays done live when they rewind it.",
"how do they do the lines that shows the trajectory of the ball? is there some sort of tracking software or are the editors drawing these by hand like the American football announcers circling plays? the lines shown when golfers hit or putt is extremely accurate so 🤷",
"Former Instant Replay Equipment Installer Here - I set up equipment, tested it, and trained refs on it for the NFL and US college football. At least as of 15 years ago, the network truck (ABC network, for instance) is set up with experts that have control over the ability to switch and replay any camera feeds to the network feed. The instance replay booth was startlingly simple: in our configuration, there were three operators, two of them refs, each in front of one of three touch screens. The operator on the far left, usually a non-ref and tech person, would wait for the network to send footage from multiple angles out onto the network, and mark the beginning and end of the plays. These plays would show up as icons on the center screen for the first ref. If more angles were needed, the operator called down to the network truck (i.e. ABC, NBC, CBS etc.) and ask for more angles. Believe it or not, this is why viewers would sometimes see so many slow motion shots from various angles replayed on TV. Not for the viewers, but for the instant replay refs! The first ref, in the center, would then touch icons to show plays from various angles on the right-hand screen, in front of the second ref, and the refs would discuss and relay information to the field. An interesting mix of high-tech with low-tech to solve a problem."
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o5dxmx | Why are green screens green? | Technology | explainlikeimfive | {
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"It's a color that stands out and isn't usually a part of the actors wardrobe etc. so that you can tell the computer that that specific shade of green is what needs to be replaced with CGI.",
"The color green they use doesn’t occur often in the subject matter they shoot (film). Modern Green screen works by keying on a specific color and then programmatically removing that color (I.e. making it transparent.) Additionally, the color leaves an edge that blends well with whatever image they put behind the Green-Screened footage So, they use that green because it’s rare. If they used, say a skin tone, then people would look partially transparent after the color-keying removal is done",
"In modern times it's just because it's the furthest away from human skin tones. Technology wise there's nothing special about it, and it just works as a nice solid color for the computer to basically just do a \"paint bucket,\" style fill/erase like you would in MS paint. [Back in the day before computers]( URL_0 ) though, they would use the color blue (one of the primary colors) and run the footage through filters in order to get a black and white \"matte,\" they could use for blending the foreground and the background together.",
"There is a really good explanation of this by captain disillusion. This is one of his more entertaining videos in my opinion, and he goes on to cover multiple aspects of green/blue screen technology and what tools and software does in motion pictures. URL_0"
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o5euq9 | How do so many satellites stay in obit without crashing | Technology | explainlikeimfive | {
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"How do about 8 billion people walk around the Earth without constantly walking into each other? Space is a lot bigger than the surface of the Earth.",
"Think about how much sky planes occupy. At any given time, there are up to 20,000 planes in the sky, compared to about 6000 satellites currently orbiting Earth (most of which are no longer operational). Satellites orbit at different heights, ranging from 160km-2000km above the Earth’s surface (“Low Earth Orbit”) up to about 36,000km above the surface (“High Earth Orbit”). That is a tremendous amount of space. In fact, even though there are 3-4 times *fewer* satellites than there are airplanes, satellites have **38,000 times more space** to orbit than airplanes have to fly in.",
"Every satellite's orbit is known and tracked. The physics of putting objects into orbit and maintaining them is very well understood. Granted, this may become a problem eventually, but for now, it's manageable."
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o5kuyv | How is a SIM card identified as switched off and not just outside of a phone instead? | Like, I lost my sim card. I'm sure it's somewhere in my home. I have a ton of old phones. When I call the number it says switch off, I wanna know if it's the same even if the sim is outside of a mobile? How does it all work. | Technology | explainlikeimfive | {
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"does it say \"the phone is switched off\" or a different message? It's quite likely that it's just a generic network message. they can't see if a sim is in a turned-off phone or if it's sat on a shelf, they just know they can't connect to a phone that has that sim card in it"
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o5o9mj | How do they upgrade a computer, that has been calculating something for decades? | If a computer has been for example serching for a really big prime number for decades, how do they upgrade it. Do they stop the calculation or what? | Technology | explainlikeimfive | {
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"The application is designed for it. It is able to save its work and resume from that save. There's not really any trick to this, just good software design.",
"If you have anything that runs for at least days, you want to design your program to have \"saves\" or checkpoints, etc. For an eli5 example, let's say you are searching for really big prime via brute force, and sequentially. You could simply memorize the last number you check. And then continue the search from there.",
"For a program that takes years to complete you write the program in such a way that it's constantly writing output and you can pause and save the state of it at any time."
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o5tmxu | What is happening when my phone claims I have good service (4-5 bars LTE) but my service actually sucks? | This seems to happen all the time. Regardless of how good my service actually is, I’m always at a few bars of LTE. | Technology | explainlikeimfive | {
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"Connection to the tower is good but the overall usage at the tower is high making everyone's connection suck.",
"There is no actual standard for what the bars showing the connection actually mean. It is up to each phone manufacturer to select the conditions required for each bar. It could for example be that they are showing how good the strength of the signal from the cell tower is. If you are close to a cell tower you would expect a strong signal and therefore many bars. However this does not say anything about how much resources the cell towers have to spare your phone. It could be that there are hundreds of phones connected to the same cell tower, all with good connection to the tower, but they still need to share the same frequency space and the same outgoing connections.",
"There are a number of reasons, but one common one that is not obvious is multipath. Multipath is where a signal is reflected off of nearby buildings/mountains/ground/etc, and results in the receiver seeing multiple competing signals. Imagine you were in a cave, and someone is trying to talk to you across a distance. If you were in an open field, you could easily understand them at that distance. In the cave though, the echoes of their voice reach your ears at slightly different times. Even though you are getting plenty of volume, it is hard to discriminate the message. With radio signals, it can be easier in some ways and harder in others. If one \"echo\" is significantly weaker strength, modern receivers can determine that the echo can be ignored, AND they can cancel out some of that echo to make it easier to hear the main signal. As more echoes are added, as long as one is significantly stronger than the others, it just takes more processing power and all the others can be filtered out. (This is one reason why newer phones seem to have fewer problems connecting to cell service. Newer CPUs and signal processors are smarter at filtering/discriminating, faster at detecting and correcting, able to handle more signals at the same time, and overall better at dealing with multipath.) The problem comes when there are two paths that are very similar, resulting in two paths that are about equal. Two paths that are about equal can result in about the same signal strength, and small changes (like the wind blowing tree limbs along one of the paths) can make one better than the other for just a moment. Plus, the same signal (same frequency) that takes different paths can actually cancel itself out in some places. (This is a bit complicated, but if you think about a lake, and there are two waves that meet, in some places the waves cancel out and the water does not go up or down.) The signal will essentially never completely cancel out, but it can cause enough of a problem to keep modern devices from having a good connection (again, even though it is getting plenty of \"volume\", ie., overall signal strength). In theory, cell phones could do periodic check-ins to determine how good their connections are, and display that instead of the signal \"strength\" bars. In practice though, that would mean a great deal more traffic for a small bit of extra information. One thing to try if you are having this issue is to turn on airplane mode for \\~15-30 seconds, then turn it back off. This will force your phone to check back in, and may allow it to connect to a \"better\" tower. (\"Better\", not necessarily closer. Due to multipath, one tower might be closer but go through/past obstructions that cause problems.) One hope for 5G is that there will be more \"towers\"/micro-cells, and less distance means less multipath. In practice, that may or may not help.",
"You can see the carrier signal from the tower. Pretty well too, it seems. Unfortunately, the tower doesn't see you so well. Either because of obstructions, a weak LTE transmitter, or both. The problem with downlink is that your phone has to send constant acknowledgement of receipt back to the tower (Basically, \"Got that, send more\"). When the tower can't see the, \"Okay, send more\", it times out and begins pinging your phone. In that moment, the behavior of your phone is dependent on whoever manufactured or distributed it."
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o5yyqm | How do 'pirated' license keys of, for example Windows, work on multiple different computers, regardless of where they are or how old the key is? | So, we have probably all at one point seen those free activation keys for Windows, that seem to work on multiple different computers, even several years after they were posted. How does that work? Is it a sort of unlimited, universal key that works for everyone? It always amazed me that a 10 year old Windows XP key could work on multiple different computers at the same time, cause when I think license keys, I think One time usage, one device usage or having to transfer it to a new system somehow. Any explanation would be great, thank you. | Technology | explainlikeimfive | {
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"For XP, Windows 95 and other older versions the key wasn't actually all that unique, it just had to fit into a specific pattern. For example [111-1111111]( URL_0 ) was a valid Windows 95 key because the last 7 digits add up to a multiple of 7"
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o64d2f | Why do some electronic devices use 12V DC input, when the internal circuitry can run off of 3.3V or 5V just fine? | Is it some form of way to shorten its lifespan? It sometimes gets annoying when other lower voltage devices use the same AC jack, and if you plug in the wrong adapter, it could burn the device. Or is it because of other high-power components? | Technology | explainlikeimfive | {
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"Most devices generate all of those different voltages with their own circuitry because they can control how noise free it is, the efficiencies, the maximum current capability, all while only requiring a single external voltage to do it. This makes it simpler for other people to integrate their device into other systems. Especially since 12V is so common, but some more obscure required voltages like 1.2V, 0.9V, to name a few are not but may be required by the internal circuits."
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o66loz | how can multiple cell phone companies claim to have the best 5g service and coverage? | Technology | explainlikeimfive | {
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"By using different measures. Some use coverage in terms of ground covered. Some use coverage in terms of number of people covered. Then they could be counting number of dropped data connections or average data speed. Despite what others are saying, there are laws in advertising and the measures they have used will be available somewhere - either in the small print in the ad or on their website",
"Local law does not prevent them from making such claims not supported by consumer consultation or specific testing. When legislation requires that such sayings be proven, companies do not say those things.",
"\"Covers most area\" \"Covers most people\" \"Fastest 5G\" \"Most reliable 5G\" All of these mean different things.",
"They also don’t usually define which “area” so it’s a pretty broad statement that can be interpreted in various ways. Best bet is to check out their coverage maps."
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o6bwd9 | When you lived in the 90s and early 2000s and saw a picture or video taken in the 90's, it always looked recent, but when you see pictures and videos from the 90's and 2000s now, they all look old as fuck. Why? | Technology | explainlikeimfive | {
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"Because we now have newer technology meaning that the quality of photos/videos are better. We are used to seeing better quality images so anything from the 90's now looks old because it is lower quality.",
"Analog photos normally had quite good quality, videotapes on the other hand, had quite bad quality. You can see this difference disappear when digital storage appears in the 2000's and we get equally bad photos and videos",
"Being used to. Eat hotdog soup for years, it will taste OK. Get used to great food, and the hotdog soup will suck. Just to clarify, I'm not saying hotdog soup tasted bad, at all."
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o6jyuh | How do televisions work? | More specifically how do pixels work? How do they know what colour to display at any given time and move with such fluidity? | Technology | explainlikeimfive | {
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"I think the exact question is \"how do displays work?\" The most common type of display, LCD, are made of multiple layer. A backlight, a color filter, and the LC. The backlight is what controls the brightness of the display. The color filter, filters the backlight's light into the three primary colors, red green and blue. The LC then filters the RGB colors to turn them into different colors. The LC is short of Liquid Crystals. It's bascially a gell with tiny plates inside. The plates can rotate freely in the gell and can be moved using electricity. When you align all the plates, they work like a window blind. They can block or allow light through them. Using this, the LC would block or allow RGB light passing through to make different colors. Have millions of these multicolored pixel on panel and you've got a display. Repeat these steps 60 times a second and you've got a video."
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o6ovpb | why do fluorescent lights make so much noise? | I mean, all lights make noise but why are flourescent lights in particular so damn loud? | Technology | explainlikeimfive | {
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"Fluorescent lights, because of how they work, require something called a *ballast* to function. A ballast is an electronic component that acts to limit the amount of current flowing through a circuit. Without this, a fluorescent light would draw more and more current in an exponential process, quickly destroying itself. The older type of ballast, a *magnetic ballast*, is more likely to buzz, and buzz louder, as the flow of current through the device changes."
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o6pb5t | DDL's (Direct Download Link) | Wikipedia says that they are "a hyperlink that points to a location within the Internet where the user can download a file.". So does that mean it's just a link to another website where there's a download button, or it's the download button itself, or what? Is right-clicking then clicking "save as" a DDL? Just kinda having a bit of a hard time understanding it, thanks to anyone who answers. | Technology | explainlikeimfive | {
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"Direct download would be a link that points exactly to the item you're trying to download. It could be the same as the item that a download button on another website gives or leads to, but it isn't necessarily the same as the download button itself (which could be a redirect *to* a direct download). Generally speaking, a direct download link won't send your browser away to another website, it'll just initiate the download of the item it links to. So if a link goes to another website (that, in your example, has a download button) it is *not* a direct download link. The whole purpose of the \"direct\" portion is that when you click that link, your download begins."
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o6samw | How do computers add gain to audio? (do they really?) | When you plug a mic into a computer, the analogue signal is being amplified, then digitzed- but many programs allow you to add extra gain to the already digitized audio. Since gain is a matter of boosting voltage, what does digital gain boosting actually involve? Is it really adding "gain," or is it actually just increasing volume? | Technology | explainlikeimfive | {
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"You know how you can make a picture brighter after you take it? It's basically that, but with sound. You're just changing the data so that it represents a louder version of the same sound (*/brighter version of the same picture*) The picture doesn't actually have inherent brightness until you display it on a screen. The sound doesn't actually have inherent volume until you play it with speakers.",
"* You can't hear digital music. * It has to be converted back to analog first. * Your computer has something called a DAC in it that converts from digital to analog. * This circuit reads the digital data and based on the numbers creates a voltage signal. * So when you turn the gain up on the computer, it's changing the data to have a higher value so when that data is fed to the DAC, the result is a higher voltage signal than you would have gotten before. > Is it really adding \"gain,\" or is it actually just increasing volume? * In this case it's doing both since increasing the gain of the digital audio signal results in a higher volume when converted to analog and pushed through speakers. * A note about gain: * The concept of gain has to do with signals, any signals. * Gain just means some relative change in the level of a signal. * Volume in the context of sound more or less means the intensity of the sound level. * It's not a technical term by any means and is not every really used in the professional audio world. * However most consumer devices use it as sort of a nickname for the gain of a sound system especially one inside your TV."
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o7033i | What makes some motors stronger or weaker than others despite spinning at the same speed? | I understand the difference in batteries (more aH doesn't mean a higher v). To be clear, I'm not referring to stepper motors or those with a constant speed | Technology | explainlikeimfive | {
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"text": [
"Speed has little to do with power. More winding wires inside the motor give more torque at a given speed and current, but take higher voltage to drive that current. Special winding arrangements, like the motors you excluded, have more complex effects."
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o70dgi | Why can different email service providers (e.g. gmail, Yahoo! Mail) send emails to one another but instant messaging apps (e.g. Telegram, WhatsApp) cannot send messages to each other? | Technology | explainlikeimfive | {
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"Email business models, like telephone ones before them, built on the idea of interconnection. App based messaging is a different business model,based on seclusion in an ad ecosystem. They could technically interconnect, bwt that's bad for the companies selling ads.",
"Email is an open specification that is set up to handle sending from one server to another. Instant messaging apps are not designed for this. They're designed where one central server controls everything. In theory, you could create a protocol that was similar and allowed for the servers to send messages to one another to forward to the right user, but there isn't a business case for it.",
"It's like school. Email is the first week of school where everyone is told to make friends with everyone else. The standard protocol is just to walk up to someone and talk to them. Open communication. That's how emailing works. Anyone can talk to anyone else they want. Messaging apps is what happens a few weeks later. Cliques start to form. People are now only talking to their friends. You want to talk to someone in a clique? Be cool enough to get into the clique (i.e., download the app) and they'll let you talk to them. Messaging apps don't talk to each other because they literally don't want to. They can set up a common protocol that allows communication, but it wouldn't benefit them, so they don't.",
"Email is a standardized format that has been around for decades. It was created as a means of communication. Modern day messaging apps have proprietary formats so that you have to use their apps. Email was created to communicate, these means of messaging were created to keep you using their app."
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o71d4q | Why do modern CPUs have such little cache? | Modern CPUs ( I'll use the 5950x for example) only have around 64mb of L3 cache. Why can't we just put gigabytes worth? I always wondered why they don't just build larger CPUs to fit the cache. Or maybe with the shrinking of components, they could fit larger amounts in the same size chip. | Technology | explainlikeimfive | {
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"The point of a local cache is that it have a very low latency. You could have more cache in the CPU but this would probably give a higher latency. Imagine you are drinking lemonade and have a small glass of lemonade and a large mug on the table. You might ask yourself why you just don't drink straight from the mug, why bother with the glass. But that would be quite inconvenient as the jug is quite heavy so you would have to put it down all the time and it would be slower to take a sip of lemonatde. And it is no big incovenience to have to fille up the glass from time to time. It is the same thing with memory cache. The small fast cache is right there next to the CPU cores and responds very fast. If you spend money on a larger cache it would be further away and use more power so it would be slower. And there is not much slowdown in getting the data from the memory into the cache from time to time.",
"Cache memory is much more expensive and hard to manufacture than RAM. Adding gigabytes of it can make the CPU cost, like, 50x more. While overall performance benefit from it would be tiny.",
"The simple answer is it's expensive. If you look back to the AMD Athlon series you'll see 512k of L2 which technically could still run Windows 10 just fine. There's more cache now then there ever has been.",
"Cache in a CPU is SRAM. SRAM is stupid fast but requires 6 transistors to hold each bit. Those 64 MB of L3 cache take 3.2 billion transistors. That's a sizable percentage of their 19 Billion transistors and overall die area We've steadily increased cache on the chips through the years. Chips didn't even have L3 caches until 2008. Even with the fast SRAM, it takes longer to find data in the cache the larger the cache is. Having a GB of L4 cache would take a while to search through and somewhat defeats the benefits of that cache eating up a huge die area. You have to keep it significantly faster than RAM or it's added cost isn't worth it",
"Cache is very expensive memory. Think about it like this, a hard drive is pretty cheap. Ram costs a little more. If you could purchase cache on it's own it would cost even more. Basically the more performant the memory, the more expensive it is. So intel and AMD need to balance its cost and performance so that consumers will purchase them.",
"The actual answer is the **diminishing returns** nature of caches. The **cache hit ratio** measures how successful our cache is in serving data quickly. E.g., a hit ratio of 90% means the cache is able to successfully speed up data requests to the CPU 90% of the time. But if we graph cache size vs. the cache hit ratio, the graph quickly hits a plateau. * For example, having 32mb cache might give us 80% cache hit ratio. * Doubling the cache to 64mb might improve the ratio to 92%, a 12% improvement. * Yet doubling it again to 128mb might only improve it further to 94%, just 2% more. * Worse, having a 256mb cache might only get the ratio to 95%. We've quadrupled the amount of expensive cache (from 64mb to 256mb) but only improved the hit ratio by 3%! This is diminishing returns. In this case, 64mb is the \"sweet spot\" because adding more cache beyond 64mb is practically wasteful. Why do caches exhibit diminishing returns? Because at any given instant of time, there's only a small amount of data the CPU will likely process next. * If you're watching a video, then the computer will likely process the next video frame, not 2000 frames ahead or behind. * If you're playing a game, the computer will likely next calculate the scene at your character's predicted position, not at some other random position in the game's world. * If you're doing a calculation in an Excel cell, the computer will likely need data in nearby rows or columns, not data in an entirely different spreadsheet. This is the effective \"**working set**\" of the computer's memory. And basically having a cache beyond some fraction of the working set will not yield much additional benefits. Further info: Example cache [diminishing returns graph]( URL_0 ). Wikipedia's description of [the working set]( URL_1 )."
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o75knh | how do they recreate 0 gravity in movies? | Like in movies taking place in space. How do they use special effects to make the actors float? Been on my mind lately. | Technology | explainlikeimfive | {
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"There are quite a few different ways to do it, with various tradeoffs. A couple common ones: * Props + editing. Use wires or other rigging to suspend the actor. Edit the rigging out of the shot. Fairly easy, lots of different ways to actually do the rigging. You can also do clever camera angles to make it look like they're floating without actually having the whole body in the shot, simplifying the difficulty of rigging/editing. * Actual freefall. The most well-known variant on this is taking a specially designed plane up and entering a parabolic arc. You're in freefall for a short time, 20-30 seconds. This is very expensive, but might be used when you have a lot of budget - or you might use it to get a few shots to see how the actor's movements \"should\" look, then do the normal prop/editing work to match that."
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o7frk6 | How were early circuit boards for chips made? | Technology | explainlikeimfive | {
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"text": [
"Originally they were hand wired/soldered. Then there was a technique called \"wire wrapping\" that didn't require soldering, but it wasn't very reliable. Connections were made by wrapping thin wires around small metal posts, which was first done by hand and then by machines. Then simple one-sided printed circuit boards were made, then two-sided, then multi-layer, etc. like we have today."
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o7l55x | why can't older and / or smaller-install-size games be loaded entirely into RAM to have nigh-zero load times? | **EDIT:** I just want to say thanks to everyone who's responded, the replies are very enlightening and filled in some gaps in my knowledge re design constraints and, well, what an install actually *is* vs what happens when it's loaded into RAM and that there's more involved than I initially understood. As I understand it (saying this in case I'm *grotesquely* wrong in some assumption here), Random Access Memory is routinely 10x faster or more ('more' probably being an understatement) than even SSD storage, and when playing games, data gets moved from your storage (whether that's disc, HDD, or SSD) or RAM when it's needed in the immediate future, so all currently loaded textures, models, environments, sound files, game logic, etc. In some niche cases you'd see things like Vib Ribbon where the 'game' itself is held entirely in RAM leaving the PS1 disc tray free to use a music CD to generate levels. I've heard of people installing Crysis into VRAM but that's through setting space aside as a virtual drive and it loaded *slower* than an NVMe SSD. So, uh...why isn't there some way to force Dark Souls 1 (*yes, it counts as old, it's coming up on its tenth anniversary*) with its < 9GB install size to be held in its entirety in my 32GB RAM, I've certainly got the overhead and reduce loading / warp times down to practically nothing? Of course, at the time games were made to play around having less RAM, for users on lower-end systems or consoles, so are they just built in ways where they don't 'take more than they need'? For modern, smaller indie games that could already fit in the RAM of most machines, is it just because having everything loaded would possibly cause engine issues? Is that why? I guess there's an unspoken 'or can they?' in my title where some program or other can force it to do so but with a caveat of 'this might break your game' | Technology | explainlikeimfive | {
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"There is nothing stopping a game (or any application) from deciding to load everything into RAM from storage when its first run and then to just sit there holding onto RAM until you close it. (Apart from obviously physical amount of RAM). I work on warehouse management software and we design our application to run entirely in RAM and it uses over 100GB of it in some situations. You already mentioned why old games don't do this, because they ran on much older systems that did not have ridiculous amounts of RAM. They had to manage loading things into and out of RAM and nobody thought it worthwhile to design it in a way where the game could decide to load more or less depending on the amount of RAM available, because it's really not worth the extra trouble. It's far easier to just design a loading system that loads everything in chunks required for a level, for example, than coming up a complicated system that's loads as much as it can from all possible future levels The same problem still exists today, sure you may have 32GB of RAM, but someone else only has 4GB. In 10 years time some else is going to write a Reddit question asking why old games like ark survival evolved (over 200GB!?) Can't load everything into their 2TB of RAM. Eventually game engine improvements might provide an easy way of loading as much as you can not tied into any specific event in the game, but it's simply not worth it for each individual developer to consider. Especially when NVME SSDs are becoming more accessible and technologies like DirectStorage and similar start to appear which will (probably) drastically reduce load times anyway. Edit: I said \"there is nothing stopping...\" when I should have said \"there is nothing technologically stopping...\".",
"You should note that \"load a file\" in most cases doesn't just mean \"copy the contents of the file into RAM\", but it means to perform more or less complex operations on the contents of the file to transform them into the data structure that the program uses. That data structure might take up significantly more space on RAM than the file does on disk, so just because all the textures (and other stuff) of Dark Souls 1 take up less than 9GB on disk doesn't mean you could load them all at once. These operations are also the reason why installing the game on a Ramdisk doesn't fully remove loading times.",
"So, you touched on something in your first paragraph that holds the answer. > In some niche cases you'd see things like Vib Ribbon where the 'game' itself is held entirely in RAM leaving the PS1 disc tray free to use a music CD to generate levels. The reason I say this is the key is because Vib Ribbon was *specifically designed* to be loaded into RAM and hang out. Most games are not; they expect to be installed to a hard drive, and they have no way to install themselves to RAM (and Windows can't even directly manipulate RAM in that way); even if they did, Windows would have to be told \"Hey, don't mess with this portion.\" What you're asking for is called a [RAM disk or a RAM drive]( URL_0 ); certain software can designate a portion of your memory that Windows then sees as a regular hard drive. Once you do that, then you can install software to it.",
"I am no expert on game design, but I am a software developer and can think of one reason why this might not be possible in the way you think: loading stuff into memory isn't \\*all\\* that happens. Let's say you're building a video game on a fairly limited system and you know that for the target system, the biggest bottleneck is going to be loading the level from the hard disk into memory. Once it's in memory, everything will be quick and easy, no problemo, but getting it there will take a while. So you get clever. Instead of having the entire level usable on the hard drive, you store a compressed version. As \\*small\\* as you can get it. This means that when it gets into memory, you're going to need to spend some time decompressing it, but that's not as much time as loading the entire level from the hard disk would have taken! CPUs are fast and hard drives are slow. Compression doesn't need to (only) be literal \"put the level in a zip file\" kind of compression. It might be things like \"instead of storing all 600 characters with stats, randomly generate them from this function and this specific random seed\". It could be \"these 20 textures are actually all the same 1 texture file, but with filtering/changes applied\". Take a room of clever people and ask each of them to optimize something, you'll find a lot of neat tricks get developed. Of course, I'm mostly bullshitting here- but you can prove me right or wrong. Find your favourite game that takes a while to load, and in another window open up the Task Manager, on the \"Performance\" tab. During level loading, watch what your computer is doing. What's hitting 100% at each moment in time? I'll bet at some points it's Disk, but at a lot of others it's CPU- processing stuff. Which is all to say: putting the entire game into a RAM drive would solve the bottleneck on loading things into memory, but it won't help you for all the other stuff that needs to happen.",
"You can create a ramdisk, copy files from disk/cd to there and launch game from there. While your loading times will get better, they will not be zero. Loading is not just loading file into memory but parsing file and making sense of it. A counter strike level is about the geometry of the place what textures it also needs to load etc, then you need to load other models and textures. Then you build a 3d model and cover it textures. It takes time, mostly cpu time."
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