q_id
stringlengths 6
6
| title
stringlengths 4
294
| selftext
stringlengths 0
2.48k
| category
stringclasses 1
value | subreddit
stringclasses 1
value | answers
dict | title_urls
listlengths 1
1
| selftext_urls
listlengths 1
1
|
|---|---|---|---|---|---|---|---|
bfuu7x | Why do they not limit speakers sound output to prevent them from “blowing out” | Technology | explainlikeimfive | {
"a_id": [
"elghret",
"elgibzq"
],
"text": [
"Some speakers do, some don't itcomes down to cost and complexity of construction and whether the company building the speakers will see a return on their inveztment.",
"Becuase there are a few variables affecting the final output to the actual speaker. If you have a quiet input you may want to turn it up louder. But that same level with a loud input could cause damage to the speakers. You can add a limiter to the overall output but it would be quite costly for most consumer grade equipment, most people would turn the volume down naturally before they got to the point of blowing speakers so it is ultimately unecessary."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bfvphf | Why does the negative binary number system work the way it does | Like, for an 8-bit number storage, the bits, in order, represents -128, 64, 32, 16, 8, 4, 2, 1. Why isn’t the first number just a negative identifier and the bits would look like, (-), 64, 32, 16,... | Technology | explainlikeimfive | {
"a_id": [
"elgpyrv"
],
"text": [
"There are a couple of different ways of representing negative numbers in binary. The easiest (for humans, anyways) one is called \"sign magnitude,\" and it's basically what you just described. One bit (the sign) denotes whether it's positive (0) or negative (1). The other bits make up the \"magnitude,\" or value of the number. So if you look at 4-bit numbers, 0111 would be 7 and 1111 would be -7. Another simple way is called \"one's complement,\" in which you just flip each bit of a number to get the negative version. For example, 0111 is 7, and 1000 is -7 in one's complement. Both of those systems have some issues, though. You can't just add numbers the same way as you can with positive numbers, and they also have some weird stuff like having two ways to write the number zero (0000 and 1000 for sign magnitude and 0000 and 1111 for one's complement). Obviously we don't have zero and negative zero, so we'd rather not have that as a possible value. So, instead, we use something called two's complement, which is done by inverting the number (flipping all of its bits) and adding one. So, to convert 7 to -7, we flip its bits from 0111 to 1000, then add one, giving us 1001. This works out to us having the system that you mentioned, where the most significant bit is negated - note that if we add everything together using that method, we have 1(-8) + 0 (4) + 0(2) + 1(1) = -7. This gets rid of the issue of having a negative 0 (flipping 0000 to 1111 and adding 1 just gives us 0000 again, since we disregard overflow) and it turns out we can use addition without any extra issues this way. For example, -7 + 3 in binary using two's complement is 1001 + 0011 = 1100 = -4, just as we would expect."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bfzf5y | How are film reels copied onto other reels (as with movies)? | After a reel of celluloid film has been exposed, cut, and pasted back together in order, how is that reel "copied" onto other reels? | Technology | explainlikeimfive | {
"a_id": [
"elhf623"
],
"text": [
"There are two methods: first is to expose the new material picture by picture using a \"dry copy\" machine. This gives you a very high quality copy and is used for making copies from the original and also at archive material. The second method is called a wet copy. You take a master copy and line it up with unexposed material using a liquid in-between so that they adhere to each other. This is run through a machine to expose the new copy in one go. This method is/was used for the disposable copies used in theatres. The quality is somewhat lower (not as sharp) and it's really rough on the master so the master is disposable as well. So you first make masters from the original cut using the dry copy method and then multiply them using the wet copy method. Source: me, a trained projectionist Edit: I simplified this by leaving out the positive/negative steps and chemical development steps"
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bg00xg | Why do software programs usually ask to restart your computer after installation, and does it really make a difference? | Technology | explainlikeimfive | {
"a_id": [
"elhg3ap",
"elhfz3i"
],
"text": [
"These programs create entries in your Windows Registry. Its a database to store eg. settings and other useful information to the right place. Restart is needed so the Programm can accsess all the information in the right order at once! Most of the time its not a big deal except if the program uses some hardware or messes with windows in a way (eg. creating a virtual drive).",
"Ever try to uninstall a program while it was running and get the message that the files were in use? If the program asks you to restart, it probably wants to place files in an area that is typically in use by Windows or some ancillary program affected by your installation."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bg0hy0 | what's the difference (mechanically) between a refrigerator, an air conditioner and a heat pump? | Technology | explainlikeimfive | {
"a_id": [
"elhiyne"
],
"text": [
"In principle nothing, both a refrigerator an air conditioner is a heat pump. The difference is that one cool the inside of a smaller box you have in a house ie a refrigerator and the other cool down a house. There is a difference that air conditioner almost always have a fan to move the air and keep it cool but a refrigerator is so small os most do not have a fan. So there is a difference because of the volume they have to cool and air conditioner i often places outside so they are designed to handle rain etc. There is even walk in refrigerator for restaurants etc and they are just like a air conditioner but the temperature you cool it down to is lower."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bg0je9 | Logical Programming -- what is it exactly? | Hi. I am familiar with different programming paradigms like procedural, object-oriented, and functional. I came to know that there is another one, **logical programming languages* with a notable example being Prolog. What is it exactly, and how does it differ from the other paradigms? | Technology | explainlikeimfive | {
"a_id": [
"elhyx92"
],
"text": [
"Rather than having functions or methods or procedures that return things, prolog has predicates. A predicate is made up of clauses. A clause says something which is true, for example: madeOfCheese(theMoon). This is a clause, and if we ask the `madeOfCheese` predicate if the moon is made of cheese, it will say that is true. You can have more complicated clauses, that depend on other things, like `madeOfCheese(X) :- madeOfBrie(X).`, which means `X` is made of cheese when it is made of brie. It's important to point out here that prolog uses Capital Letters at the start of Variable Names. But a predicate always either answers true or false. So how do we get a good answer out of it? Lets say that we have the following clauses: nat(zero). nat(succ(X)) :- nat(X). Which say that something is a natural number if it is zero, or it is the successor of a natural number. Now let's say we want to add two of these 'numbers' together. The `succ(X)` isn't a predicate though - we can build compound terms using the same syntax. We can't have something like `add(A, B) :- ...`, because it can only return true or false. Instead, we say that there is a number C that is the answer, i.e. `add(A, B, C) :- ...`, like the following: add(A, zero, A). add(A, succ(B), C) :- add(succ(A), B, C). This has two clauses, both of them important. The first one simply says A+0 = A. It does something clever here, and sets A and C to be equal, which is called *unification*, and is how you get answers out of a predicate. The second clause subtracts one from B, and adds one to A, and adds those together. Eventually, B becomes zero, and you get A + 0 = C."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bg0oe5 | How pirates in the internet breaking the video games and upload them to the torrent sites? | As I know, most of games are consist of .dll libraries, textures, cfg files and other game companent. They are all ciphered. So, the question is, how anonimous pirates transform all these components in just setup.exe . | Technology | explainlikeimfive | {
"a_id": [
"elhkxuv"
],
"text": [
"> They are all ciphered. I suspect you mean encrypted but that is not the case. If you purchase a game from Steam there is a installer you download and run and the output is a unenrcyped version of the game. When stop you from sharing it with your friend is code that check with the seams service if you are allowed to run it. So a crack of a game might just bee to replace the dll files that check for that and just say you are allowed. It might also be that you the game execute have more complex way of checking that so you need to change the program. Creating a custom installer that install the game like the original program do it not hard, decompress the game files and add stuff to the system registry or what else you need to do. You only need to look at what the original installer did. compare the state of the computer before and after you installed the game and you know what changed. Encrypting software that run on computer that general users have do not work as protection. Because they need to be able to decrypt the game to run it you need to send the decryption key to the computer. If you change the program that receive the encryption key or look in the memory it uses you can extract the key and decrypt the game. DVD an blue ray tried that and it has failed because you can rip movies. Pre release games might be encrypted so you can download them before the game is released but then you do not have the decryption key and can't run the game. When the game is released you get the decryption key and dectypt the files. But then as a pirate you could capture the key or just use the decrypted fils that is installed on the computer."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bg19ew | How do scientists measure the height of a mountain | Technology | explainlikeimfive | {
"a_id": [
"elhmc8x"
],
"text": [
"To calculate the elevation of a mountain, scientists would measure the distance between two points on the ground and then measure the angles between the top of the mountain and each point. Trigonometry, it’s actually one of my favorite maths."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bg265h | what exactly is “rendering” a video and why does it take so many computers so long to do them? | Technology | explainlikeimfive | {
"a_id": [
"elhrz45",
"elhs4kf",
"elhs93j",
"elhswod"
],
"text": [
"Images and videos are just many lines of computer code, video rendering is the process of converting this code into images that you can see on your screen. This takes so long to do because as the quality of the image increases, so does the amount of code that image is made of. This of course increases the time it takes to render the image Becuase more code needs to be converted and since a video is just lots of pictures played one after the other, you can see how much time this will build up to.",
"When you are looking at a video, everything is flat. You are seeing all of the work that the computer is going into to make that image. It is just reading a series of instructions on where to put dots of color on a screen. When you are playing a video game, you still just see dots on a screen. Put your computer not only has to know where to put the dots on the screen, but it also has to keep track of what those dots mean in a 3D space. It has to run physics and do the math involved in creating the world that you were looking at. And that is infinitely more complex than just showing a video. A helpful analogy might be to think of video as a play. Running a video is simply actors acting out the play. There isn't that much work in it. Rendering the video, on the other hand, it's all of the work that goes into writing the play and building the sets and directing the actors and the actors learning their lines and everything else that makes the play actually work. Once all of that hard work has been done, it is far more easy to add extra showings of the play, and nobody would have to do the work again merely to show a recording of the play.",
"Rendering is conversion of your abstract model of a scene into screen pixels so people can see it. The real world is complicated, lots of moving pieces, each with their own shape and color and orientation. If you want to show an oak tree in a video, you could go with a circle of green on a line of brown. This could very quickly be translated into screen pixels. Alas, if someone looked at your video, they would say \"WTF is that? is it a tree?\", and that would detract from the idea you were trying to convey in your movie/videogame/whatever. If you have a model of an actual tree with thousands of leaves slowly rustling in the breeze, that's much, much more computationally expensive to translate into pixels. But, it looks like a real tree when you do that. In the movies, where rendering is off-line and they just use the output pixels, they can afford to do really expensive things like this. In a video game, that would give you 1FPS lagginess, and users don't like that. So games can usually look as good as their canned scenes or movies.",
"A finished video is a file that is essentially a whole bunch of image files strung together. There's also all the tricks in there to reduce the filesize which makes it more complicated, but for simplicity, let's pretend it's really just like a bunch of jpegs in a row. Let's say you're working at Pixar making a 3-D animated movie. You would be using programs to build models and textures of the characters, set them in a scene, give them rules on how they move around in the scene, and tell the program where the camera is. At that point it works a lot like a video game, and when it plays a preview of the movie, the computer has to take all this information about 3-D space, and figure out how to squish it onto the 2-D monitor every single frame. This is super computationally heavy, and you can only put so much detail into the animation when it's being played because of all of this computational overhead. This process of flattening all of the information onto an image on the screen is rendering. To make a higher quality movie that doesn't require a super computer to play, Pixar will put together all the animation files and send them to render into a video file all at once. It takes so long because it's as complicated for the computer to do as I said before. Taking a bunch of objects and lighting and physics rules and having the computer turn them into a movie is a huge math problem that takes time for the computer to work out."
],
"score": [
6,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bg2s7q | what happens at the hardware level when a computer executes a for loop? | Put another way: what was the difference in hardware between the first computer that could run a for loop and the computer it superceded? | Technology | explainlikeimfive | {
"a_id": [
"elhwd2g",
"elhw6zk",
"elhx7ww"
],
"text": [
"The processor keeps track of its current location in the program in something called a [program counter / instruction pointer]( URL_0 ). Normally this counter progresses sequentially, pointing to the next instruction each time. Any change to the standard flow of the code (whether it's a conditional statement or a loop) uses a JUMP instruction which sets the program counter instead of just incrementing it.",
"Nothing that has any relation to a for loop. The for loop is a software construct, and does not require any special hardware. Any digital processor at its core (har har har) performs tasks roughly the same.",
"A for loop isn't special. It's at best a fancy while loop. the for loop for( A;B;C) { D; } is functionally equivalent to A; While( B ){ D; C; } which both are translated down to assembly and from there machine language. The hardware doesn't care what structure your loops have, it's all going to boil down to the same set of instructions either way."
],
"score": [
10,
3,
3
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Program_counter"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bg3u22 | How does my scale calculate my BMI, body fat percentage and body water percentage? | Technology | explainlikeimfive | {
"a_id": [
"eli3nky"
],
"text": [
"Body fat and body water resist electricity differently than the rest of you. The scale sends a small bit of electricity through your feet, and calculates how much is resisted, and with some math and guess work can estimate your fat/water percentage."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bg4ntk | What happens when Computer is hanged up very hard | Technology | explainlikeimfive | {
"a_id": [
"elic3mj"
],
"text": [
"no way to tell for sure without specialized debug hardware/software. & #x200B; it could be hardware or software related. & #x200B; one possibility is interrupt storming. interrupts have a priority level, but in general are high priority requests that must be serviced above all application processes. keyboard/mouse inputs are examples of some interrupts. and if the kb/mouse are no longer responding than it means the computer's resources are busy servicing something higher priority. & #x200B; another possibility is that the OS itself has entered into a bad state somehow and is no longer responsive."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bg5r8r | Why is it concerning that Jet Blue is using facial recognition data from the US government to facilitate boarding? Is this that different from just having pictures of your face on file to compare with? | Technology | explainlikeimfive | {
"a_id": [
"elilryx"
],
"text": [
"Actually, if OP had researched this, the headline is misleading. What JetBlue is doing, on International Flights (where you are required to present your passport to board!) is capturing an image of the traveler at a voluntary kiosk, transmitting that to Customs who then does a biometric match and clears the passenger for boarding. JetBlue isn't tracking people, and isn't amassing a giant database of travelers. Remove the tin foil and back away from the Koolaid. This is a positive thing for international travelers."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bg75xa | What happens when you take a long exposure photo? | Technology | explainlikeimfive | {
"a_id": [
"eliuh6s",
"eliu8z0"
],
"text": [
"The shutter stays open for a longer period of time, allowing light to enter the lens for that amount of time. So in a normal photo, the shutter stays open for much less than a second, so only the light that was let in in that quick time will be shown, but if you shoot with let’s say a 10 second exposure, the shutter will let in light for 10 seconds. Thats how blur happens on cameras. If you have seen star trails, those work because they set the exposure for hours, and as the earth rotates and the stars move, the light comes from a slightly different spot. Long exposure also allows you to let in more light over time than you could in a split second. In that case, you could take still photos at night, and they sky would look bright blue, the setting would look slightly lit up as well. Hope this helped!",
"The part of the camera that takes in the light (the click bit) stays open longer, taking in more light (very long pause between clicks) the photo then takes in more light information stuff. So if it’s very dark it has longer to look at stuff. If it’s bright and you do it, you’ll have lots of white. Because theres too much light."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bgb2y6 | Why do some online games lag so much to the point where they’re unplayable even though you’re getting high download speeds from the ISP? | Technology | explainlikeimfive | {
"a_id": [
"elju9sr",
"eljnnws"
],
"text": [
"There's a difference between latency and bandwidth. Bandwidth is your overall download speed. Latency is how long it takes for any information to cross over. You can have good bandwidth and bad latency (EG, sending a crate of hardrives by overnight shipping) You can have good latency and bad bandwidth (EG directly connected by an old school phone line) There are a number of factors that might be affecting the latency. 1) It might not be your ISP at all, the server for you online game might be busy, and the latency is you waiting for the server to get to your computer. 2) The server might be far away, it takes time for your ISP to figure out how to send your stuff to the server's ISP in another country, then for everything in between to make arrangements for your stuff to get sent, then repeat for the reply. 3) Your ISP or someone in between you and the server might be losing some of the stuff you are sending. You thus have to waste time resending stuff. 4) Your ISP or someone in between you and the server might also be really busy, you have to wait in line for your stuff to get sent.",
"Could be server lag. If the game servers are in a different country you can still get high ping. also upload speeds are very important as your data would not be getting sent to the server within the time limit."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bgfica | What technical innovations (brushes, paints, canvas) have allowed artists to create ultra-realistic portraits, or is it all just skill? | Technology | explainlikeimfive | {
"a_id": [
"elkki8s",
"ell2fjy",
"elkea0v"
],
"text": [
"It's both, really. And a little bit more... Of course paints are getting better. Machines spitting out perfectly ground pigments with the medium just right, and brushes with finer bristles... That helps. What also helps is the fact Da Vinci existed. He did amazing work. Artists learned from him and improved on his technique. The next generation did the same. Da Vinci did it with the artists before him. Everyone added to the general knowledge pool for artists, and they all benefit. Don't forget, doing photo realism before photos was really freaking hard. Objects move, models move, lights move... With no 100% stable source to work from, getting it \"just right\" would be a nightmare. And lastly, the religious element. Most art, and almost all that survives from that period, was funded by the church. They were walking a fine line between awe-inspiring murals and violating the whole \"graven images\" commandment. Galileo was born just after Da Vinci's death, and they drug him in front of the Pope for what he was doing. It was complicated.",
"Watch the documentary “Tim’s Vermeer” for one example. In it, Tim Jamison reverse engineers the process that he assumes Vermeer must have used, involving mirrors and lenses.",
"It all comes down to an artist's skill with their particular medium. I have seen realistic pastel paintings and realistic colored pencil drawings. I've seen spray paint on trees and even tattoos that boggle the mind."
],
"score": [
11,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bgg5t7 | How does a battery work? | Technology | explainlikeimfive | {
"a_id": [
"elkkif6"
],
"text": [
"There's two important parts inside batteries: one material which has lots of extra electrons, one material which has a lot of space for those electrons, and then there's something to keep the two separated. When you connect metal or something else conductive between the two terminals of the battery, it creates a path for all those electrons to flow from the material with an excess to the material which wants the electrons."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bggq4r | How self-driving cars are able to stop at intersections with no traffic lights and still know when it’s alright/safe to turn. | Technology | explainlikeimfive | {
"a_id": [
"elkogr2"
],
"text": [
"> We use all our senses to make a decision like that; like sight, hearing and judging of the speed and acceleration of the other car. The sensors and computer of a self-driving car are better at that than we are. I'm not sure why you think they wouldn't be. e.g. lidar is much more precise than the eye at judging speeds."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bgi3ar | How are copies of celluloid film reels made? | I know the chemical process behind celluloid photography, but how do you go about copying the contents of a given film reel onto another? | Technology | explainlikeimfive | {
"a_id": [
"ellm68w"
],
"text": [
"They use a device called a contact printer/copier. It's basically a mechanized lightbox that is used to photograph each individual frame from a master onto a new piece of film, called the release print. So what they do is take the original camera negative, which is used to create an interpositive. You do all your grading and editing work with this. Then it's used to create an internegative. The internegative is then used to create release prints for theaters. In the modern age, the original film negative is scanned into a computer, where a digital interpositive is created. Once all your post-production is done, it's then copied back to film using a digital film recorder. Which works like the contract printer, but it swaps the film master for a high resolution video display. From there you use the contact printer to make release prints from the internegative from your film recorder. Or you can use your final digital interpositive to create digital video files that can be played on cinemas using digital projectors."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bgiisp | What is object oriented programming all about and why is it so good ? | Technology | explainlikeimfive | {
"a_id": [
"ell5c2a",
"ell82j3",
"ell8e59"
],
"text": [
"All programming languages fall on a scale from \"computer logic\" to \"human logic.\" Machine code, for example, which is essentially binary (1's and 0's) and assembly language are as close as you can get to a computer's \"native tongue\" of sorts. On the other hand, a scripting language, such as python or ruby, follows a human-centric understanding of how things are processed, by going from task A to B to C and so on. The closer you get to the \"computer logic\" side of programming, the easier and quicker a program will run, but it's harder for a programmer to wrap their head around the process. Object oriented languages is a sort of middleground if you will that makes programs run relatively fast while still being somewhat intermediate in terms of difficulty. The way OO languages work is by compartmentalizing processes, called-tasks, and constructors into their own \"objects\" within the code. The first \"object\" that runs by default is called \"main,\" and it can call other objects to run within itself, which can use variables as arguments so that a different result can be passed through the same object process. Think kf it like a calculator: every type of process from multiplication, subtraction, and so on is called from \"main\" once the \"equals\" button is pressed, and the arguments are the numbers in the equation. Hope that helps, OP! Bachelor's grad in CIS/App Development here.",
"Object oriented programming is based around organizing data and code into structures called objects. Instead of having some data in memory and a bunch of procedures that call each other to process this data, you group procedures together and associate data with procedures meant to work on it. That's a bit abstract, so as a more direct example - previously you might have had some pieces of data called dog_1_name, dog_2_name, dog_1_color, dog_2_color, and some procedure called show_dog. show_dog(1) would print the name and color of dog 1, and show_dog(2) would print the name and color of dog 2. If you structured this in an object-oriented way, you would notice that you were logically working with just two dogs, and that all dogs are affiliated with this procedure show_dog. So, you can create a 'class' called Dog - a class is a template which describes the procedures and data that an object can have. You can use this class to create two dog objects. Dog dog1 Dog dog2 These dog objects are now structures in memory that chunk together all the data and actions logically associated with the two dogs. If you wanted to display a dog, you could do dog1.show() And this tells the dog1 object to display whatever data it has inside of it - presumably the name and color. Object-oriented programming is fine. It's not the end-all and be-all, it's just one way of organizing code and data, and it works well for some problems and badly for others. Pretty much all modern languages include varying levels of support for native object-oriented programming, as well as support for other styles. It is often taught first because it has a tendency to align well with real-world structures, and this can make it easier to build intuition for students.",
"We've heard that a program is a set of instructions given to the computer to make it do something. If we view a program as just that, an ordered list of steps, as we try to design bigger and more complex programs, it becomes harder and harder to try get them to communicate effectively with each other, or model certain behaviors, or try to change one small part without breaking the whole thing, or to reason out their behavior without the programmer tearing their hair out, etc. So we stopped structuring programs as just step 1, step 2, step 3 (though at heart they still are so, and get converted to these steps in the machine language), and one of the alternatives was object oriented programming. An object is a bundle of some functionality and some data. We just keep them together when they are logically related... like if you model a \"Car\", it sounds convenient to say carA.getCurrentSpeed() and carA.somethingElse() instead of writing getCarASpeed and getCarASomething lying around just anywhere in the program. Also, only some of any object's functionality is usable from the outside (should anyone be allowed to tell it how to do its job? If it needs to store the fact that 1 mile per hour is 1.6 kmph to be able to give you its speed in both units, is it wise to let anyone just change this fact from outside?). So if you structure your program as just a bunch of these objects and the rules of interactions between them, it helps solve many of the problems i listed above with 'bunch of instructions one after another' programming. This is object-oriented programming."
],
"score": [
5,
5,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bgjkdp | How has the storage capacity in hard drives and other memory storage devices increased while the physical size of these devices has decreased? | Technology | explainlikeimfive | {
"a_id": [
"ellbb5c"
],
"text": [
"At the end of the day, what they're ultimately trying to store is binary, 0s and 1s which is just checking whether something is there or not, or switched one way or the other way. In theory, you could represent such data with single molecules, atoms, or even electrons, but the technology isn't quite there yet, though that's where we're heading. So basically, the technology that is storing these values are shrinking, which allows for either smaller devices for the same amount of storage, more storage in the same size devices, or both. We also figure out more efficient ways of storing information. For example, the number 10000000 takes up 8 characters, but you could also represent the value as 10\\^7 which only takes up 4 characters, not that that's how they're stored digitally, but just an example, similar methods can be used on storage to effectively store more data with less information needed to represent it."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bglwrb | How do you get rid of a tattoo with lasers? | Is it actually lasers? Does all the ink disappear? Where tf does it go?!? | Technology | explainlikeimfive | {
"a_id": [
"ellttke",
"ellu0n6"
],
"text": [
"The Laser breaks down the ink particles into smaller pieces your bodies immune system can dispose of",
"Yes - it is actually lasers! Tattoo ink consists of very large particles embedded deep in the skin. Your body _wants_ to get rid of it, but the particles are just too big for your natural immune system to deal with quickly (it does do it _slowly_, which is why tattoos fade over time) so the ink particles sit there. A tattoo removal laser hits the ink cells with very high energy light, which shatters the ink particles. These broken particles are now small enough for your bodies natural immune response to deal with, so they get further broken down and excreted (just like all other waste products). It usually takes multiple treatments to break down all of the ink enough for your body to deal with it all, but after a while it will disappear completely."
],
"score": [
7,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bgouli | Are radiators really the most efficient central heating option out there? How is running steam through metal and having it radiate/convect an entire room the most viable option we have? | I find it almost unfathomable that this actually works well enough that we still use this today (as a physicist). I'm sure there MUST be more cost and energy effective options now, even if there wasn't in the past? | Technology | explainlikeimfive | {
"a_id": [
"elml32r"
],
"text": [
"All heaters are in the 90-100% efficiency range from an energy perspective because usually you consider the waste energy to be heat. So the actual question is which one is more expensive for your use case. This depends on gas/electricity costs, and how big a building you want to heat. The losses in these systems are how much energy it takes to move the water/steam/air, and what you lose to the exterior of the building along the way. Steam radiator systems are great for large facilities/ campuses because it gives off its energy when the steam comes in contact with the cold face of the radiator, and water carries large amounts of heat. These are usually heated using gas boilers. For slightly less huge buildings a similar system with water is pretty good too. For small, single unit residences electric and gas powered furnaces will basically win out based on whether gas or electricity is cheaper in your area. These have the advantage of being forced air, which if designed right will evenly distribute it. True radiators (like are used in hockey arenas) are pretty inefficient since the radiating pieces have to be very hot to direct meaningful heat energy out."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bgpsiu | How do scientists record rainfall? | Technology | explainlikeimfive | {
"a_id": [
"elmrju3"
],
"text": [
"[Rain gauges]( URL_0 ). They're just a little tube that collects water & lets you measure it. It doesn't really matter how big the tube is (within reason) - an inch of rainfall is an inch of rainfall whether it's the size of a DVD or football field."
],
"score": [
6
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Rain_gauge"
]
]
} | [
"url"
] | [
"url"
] |
|
bgqdnf | How phones still can call ambulance when there's no simcard put? | Technology | explainlikeimfive | {
"a_id": [
"elmt2r8",
"elmsy2z"
],
"text": [
"The antenna isn't actually in the Sim card it's in your phone. No sim card, to your phone, just means you haven't paid for access to a phone network, it doesn't make the phone physically unable to dial into one. For emergency calls it will make an exception. It's also why you can make emergency calls if you have no reception on your network, because they can be dialed into **any** network, so as long as your withing coverage of a phone network, it doesn't mater if it's your own or not, you can always make an emergency call",
"A SIM card is used for identification of an account/authorization to allow the phone on the network. Emergency calls to 911 bypass that, the towers are configured to allow calls to 911 through from any phone capable of talking with them."
],
"score": [
11,
8
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bgrfrz | 5G uses millimeter waves, but why can't we just fit more devices on existing 3G/4G spectrum? | Can't we compress data transmission more or transmit more quickly? Don't understand why we are running out of spectrum, are we really effectively using what we have? | Technology | explainlikeimfive | {
"a_id": [
"eln0f6k"
],
"text": [
"Systems and network specialist here: Only certain frequencies are available for consumer electronics due to government use. Certain frequencies are also less stable and can be interfered with more easily, there must also be a somewhat large 'space' between frequencies, the same as a radio, when inbetween two stations you can often here a little of both. There are ways to improve the current network technologies however the receiving equipment is very expensive to replace and update so although phones and other devices that can be updated to accommodate new technologies often and for, the receivers can't be. There are different routing methods and bandwidth allocation algorithms that can be pushed about older hardware however users wouldn't really notice any major improvement unless the network is heavily congested in one particular area"
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bgs7l2 | Why do streamers have a dedicated streaming PC? Wouldn't it be simpler to game and stream on the same one, without all the capture cards etc? | Technology | explainlikeimfive | {
"a_id": [
"eln4nye",
"eln4uqf",
"eln4o9j",
"eln668s",
"eln5nvt"
],
"text": [
"the encoding process can be intensive as such would cause poor performance on the gaming PC so to get the best performance they use a separate PC",
"Alongside the pure performance aspect, as the saying goes, the show must go on. If your gaming PC has any issues, crashes, locks or whatnot, if that's also your stream source, you're off the air. If you have a separate PC the is running the stream, there's a lot less variables so if the game bungles your PC, it's only the gaming PC that's affected whereas you can continue streaming while it reboots or whatever it needs.",
"Because capturing and compressing the video is extremely CPU intensive to the point it would kill the game performance. Sure, if you’ve got a God In A Box computer with 10,000 cores you could do it, but its easier to have a dedicated streaming/capture machine.",
"Besides the game already using a lot of not most of your available power, streaming requires you to encode and compress the data in real time (1080p 60fps) and send it to the streaming service. So to get the best quality on both you usually need a second pc when streaming modern games. Also i believe streaming uses the CPU so streaming PC is usually focused on a good CPU (i think) instead of a GPU, if any",
"This may now change with the latest version of OBS that contains all the stream rendering inside Nvidia's GPU video chip cutting the CPU usage down considerably. Available on series 9 and up."
],
"score": [
15,
6,
4,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bgubms | When a computer program says to restart the computer to complete installation, does simply shutting down the pc and opening it next time have the same effect? | Technology | explainlikeimfive | {
"a_id": [
"elnn0uh"
],
"text": [
"Yes. The restart is pretty much just a shutdown immediately followed by a startup. The important part for the installation is that the computer went though the usual startup steps again and this time with all the steps and values and the installation program just changed."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bguzb9 | How Microprocessor works? | Is there any simple visual guide how Microprocessor works? From the internals, to how electrical current can change the positions of transistors inside and how it can run simple commands? For example a chip may contain thousands of transistors how does a electrical pulse sends information to tell the chip which transistors go "0" and which one go "1"? | Technology | explainlikeimfive | {
"a_id": [
"elnv7yk",
"elofqui",
"elnv8en"
],
"text": [
"It is a bit difficult answering a question like this for ELI5, because computers are so layered. You start with the basics of how transistors and electricity work. You then put those transistors together in simple circuits called gate which make some simple calculation (like \"the output is 1 if and only if both inputs are 1\" or \"the output is 1 if either of the inputs are 1 but not both\"). Then you build up more complicated circuits using those gates that do something more elaborate (for instance, adding two numbers written in binary or storing a pattern of 1s and 0s for later). Those more complicated circuits can be combined to make a device that can perform actions in a sequence of steps and even alter that sequence by looking at patterns of 1s and 0s stored in its circuits. At that point, you have the beginnings of a computer, and the rest is adding on bells and whistles. As for guides: there are books that cover this sort of thing. You might try checking out your public library. There are also Youtube videos out there that might be helpful. Ben Eater has got a whole series where he builds a computer from scratch, although that might be more technical and detailed than what you want.",
"It would be wrong approach to answer this question as OP would like to. The right approach is to use *abstraction*. * First you learn how transistors and analog circuits work * Then you learn how to construct logic gates (AND, OR, XOR etc.) from analog circuits. By this time you should no longer care about the transistors as long as you work within specified electrical parameters (voltage, frequency, temperature etc.). * Then you learn how to construct digital circuits (ADDERS, MULTIPLEXERS. TRIGGERS etc.) from different combinations of logic gates. * Then you learn how to combine multiple ADDERS to sum binary numbers and combine with other digital devices to move the result to memory devices made from TRIGGERS etc. * By this time you might be getting the intuition needed to see how you can possibly put together a rather complicated device that could do a multitude of things depending on what binary instruction it receives. This device would possibly be Arithmetic Logic Unit (ALU) - a crucial part of a processor that performs arithmetic and logic operations. * Next thing is to possibly combine this ALU with a memory registers to make a primitive processor. Processor would receive binary instructions that would say e.g. take this byte from this memory location and take this number, then give both these numbers to ALU and instruct it to sum them up. ALU would then put the result in some known location. As you see, it might not be possible to explain intuition to someone who has not gone through the pains of learning each level of abstraction here. When processors are designed multiple people work on that and they work on different levels. EDIT: For further reading (watching) I'd suggest this MIT lecture series. I'll link the 5th lecture which starts by explaining the transition from analog voltages to digital 1s and 0s. URL_0",
"I'm not aware of such a guide, but you may be interested in Minecraft videos that show designs of CPU... in Minecraft. You would be surprised how accurate that might be. That being said, you might get a pretty good understanding knowing those ingredients: - a transistor has 3 wires: one input that control it (ON means pass through, OFF means you shall not pass), one input that carry the data, one output that carry the data if it could pass through or is dangling otherwise. - memory: you send it an address, it respond with data, that's a \"read\". you send it an address and data, and it memorize it, that's a \"write\". - program counter: it's the heartbeat of the CPU. It's a counter that do +1 every cycle, without asking. - instruction: every cycle the \"instruction pipeline\" will read the memory to get an instruction. It will read at the address indicated by the program counter. - decoding: that instruction is cut into pieces, some bits says what to do (load/store/jump/add/multiply), some bits says where to get the inputs (this load need an address, it will find it in register 14, etc...) and where to put the output (this multiplication will produce its result in register 5). - dispatching: a routing network (kind of like a bunch of train tracks with intersections made of transistors which are controlled by the instruction bits) will activate the circuit that do the operation and send it the data of the registers that are input, and propagate its result to the registers that are output. - compute: that's what people explain most of the time, a lot of transistors that compute the actual operation. To me, the most interesting part of a processor is the memory subsystem. That is, the registers, the cache, the memory. That's much more powerful than the computing unit. In reality, you can compute using memory only! But that's a story for an other time."
],
"score": [
13,
6,
5
],
"text_urls": [
[],
[
"https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-002-circuits-and-electronics-spring-2007/video-lectures/lecture-5/"
],
[]
]
} | [
"url"
] | [
"url"
] |
bgvf06 | How do phones avoid a feedback loop or echo in speaker mode | In speaker systems we sometimes experience an annoying echo especially if the mic is too close to the speaker. In phones its in close proximity and yet we don't get the extremely jarring feedback loop. What are the mechanics involved and how do phones do it so well? | Technology | explainlikeimfive | {
"a_id": [
"elo185c"
],
"text": [
"/u/Uumus guessed it correctly. First of all, the phone is designed to try to minimize how much of the speaker output gets to the microphone. But it can't always do this well enough. In that case, a cancelling circuit is added. It \"subtracts\" the speaker output signal from the input of the microphone, so the feedback loop is virtually eliminated. This is typically done in the digital domain by a Digital Signal Processor, after your analog voice input has been turned into a stream of bits (1s and 0s). That's because there's a DSP chip being used anyway, and it's easier to do the subtraction accurately with digital signals."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bgwbx5 | How do mobile chipset manufacturers achieve incremental performance improvement year after year? | What do they improve and how do they do that ? | Technology | explainlikeimfive | {
"a_id": [
"elo6vp5"
],
"text": [
"big upgrades include transistor size where you go from 14nm to 10nm etc. Right now on mobile phones, flagship androids that came out this year and the iPhone from last year use 7nm transistor size. The smaller the transistor, the more transistors you can fit and better performance. Sometimes it's the way these transistors are arranged or how the cpu cache is arranged or how much more cache there is. Sometimes all the components in the cpu itself can be rearranged and give better communication between each component and thus squeezing more juice and effeciemcy. There's lots of factors that can give these incremental upgrades"
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bgypv4 | How does your mobile phone upload / send data to a cellphonetower or WiFi router? | I understand that cellphonetowers have very powerfull antennas to send data to the receiver on our phones. But how does a phone send data back? The antenna on a phone isn’t powerfull enough to send data over great distances? Same goes for wifi; the router contains a big antenna to send data, but the phone doesn’t have a large antenna to send data back? | Technology | explainlikeimfive | {
"a_id": [
"elojmun"
],
"text": [
"Big antennae allow for greater range of both sending and receiving radio signals. That's why you could, back in the day, get a big ol' antenna for your car that would boost the range that you could hear a radio station by for a bit. The antenna in your phone is large enough to receive and transmit back to the cell tower, but the cell tower's antenna is the major contributor to that situation; you'll notice that you need significantly larger and more exposed antenna in all but the most expensive walkie-talkies, which simply pick up and broadcast anything on a certain channel frequency, rather than use rotating code to tell a central controller/router what signals go to what devices."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bgyzaw | How does the International Space Station(The ISS) gets their Oxygen supply? Does it gets refilled on a regular basis? How does it gets refilled and what is the capacity of their Oxygen tank? | Technology | explainlikeimfive | {
"a_id": [
"elop3ql",
"eloocre"
],
"text": [
"Primarily via water electrolysis (running an electric current through water to break it down into Hydrogen and Oxygen), though they also get supply shipments from Earth every couple months. They also have a backup system that can generate oxygen by burning lithium perchlorate. Not quite sure what their storage capacity is though.",
"They ISS has a machine that reforms CO2 into O2. They also have frequent resupplies of water, which is 8/9^ths oxygen by weight and is much lighter to store than O2. The other important breathing gas is N2, and while the Russian Progress can bring up N2 in pure compressed gas form, the other resupply solutions can only bring air."
],
"score": [
16,
7
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bh0h6k | How or why did the QWERTY keyboard become the primary/standard layout across most of the world? | Technology | explainlikeimfive | {
"a_id": [
"elp0lzr",
"elp1gcp",
"eloz7zu"
],
"text": [
"QWERTY became the standard back in the days of old fashioned typewriters. The way it was originally designed, people were jamming the ink ribbons due to typing too fast. To avoid this, the QWERTY style was introduced which forced people to type slower and reduce jamming issues.",
"QWERTY was designed, as other commenters have said, to stop mechanical issues in type writers from jamming by separating commonly used letters away from eachother. As per u/Eats_Ants article, apparently it also was designed to group together letters that were similar in morse code, so you could prepare to type the letters as you found out what they were. As to why the exact QWERTY layout stuck, and not some other similar spread of keys, according to wikipedia that seems mostly due to it being used on a specific highly [successful product]( URL_1 ), the remington standard no 2. Some countries do use other layouts than QWERTY, but most are extremely similar variations. As to why its still in use, well from what I can tell the best explanation is we really can't do better, or at least changing is not worth it. Other key layouts exist that purport to be faster, [such as dvorak]( URL_0 ) but theres little to no evidence that those changes to layout produce a significant speed up in key strokes. It seems that quite simply the efficiency difference between QWERTY and any 'better' layout just is insignificant. I know someone who chooses to use the DVORAK layout, and can confirm their typing is no faster. In theory what would make a key layout fast would be firstly how 'far away' keys used all the time are, and secondly how 'bunched up' keys are that are generally used sequentially. DVORAK tries to keep all your vowels and most used letters on the home row, so you dont have to move your fingers at all to reach your most used letters. This may produce up to a 4% speed difference. Both DVORAK and QWERTY do a good job of making sure you dont need to usually sequentially hit keys with the same finger one after the other. (editted with a bit more info)",
"Not such much why we still use it, but a super brief history and some explanation. URL_0"
],
"score": [
22,
18,
6
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/Dvorak_Simplified_Keyboard",
"http://type-writer.org/wp-content/uploads/2013/10/SAM_2195_clipped_rev_1-1.png"
],
[
"https://podcasts.apple.com/us/podcast/the-indicator-from-planet-money/id1320118593?i=1000435094718"
]
]
} | [
"url"
] | [
"url"
] |
|
bh0kvr | How can a bank determine fraudulent activity from a single transaction? | Especially if that transaction isn't typically out of the normal for the card holder (like being used at a gas station within 100 miles of the card holder's address)? EDIT: I know this looks like I'm trying to figure out how to steal someone's debit card and not get caught, but I'm asking generally about something that happened to me today. I was told to generalize it as my original question was too specific. | Technology | explainlikeimfive | {
"a_id": [
"elp2rcq"
],
"text": [
"In current day banking it's just machine learning. They fed an AI with a bunch of labeled data, and now it's able to say which transaction is likely fraudulent and which is not; just like the YouTube algorithm showing you stuff you probably want to click on. Noone knows what exactly the algorithm is thinking, just that it works."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bh20vr | I have a fairly new computer but am able to do a recovery of thousands of images | I have a fairly new computer which I use mostly for web browsing, watching YouTube videos, and schoolwork. After deleting some papers, thinking I had backups, I realized I needed access to them. I downloaded some file recovery software and ran it. I thought it would retrieve things I deleted from my computer, but it ended up recovering thousands of images making it very difficult to find my school work. Why were there so many images on my computer to be recovered? | Technology | explainlikeimfive | {
"a_id": [
"elpbyef"
],
"text": [
"When you go to a web page, and there is a picture, the picture is downloaded to your browser cache. The browser deletes them when it's used how every much space you allocated for it, not usually a whole lot."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bh3aly | How do free apps with no advertisements make money? I am trying to figure out how the Citizen App makes money? | Technology | explainlikeimfive | {
"a_id": [
"elq1oin"
],
"text": [
"There are many ways free apps can make money’s Almost all free apps and sites have ad space they sell either it be a banner or a full section on the app. Many of them offer in app purchases or micro transactions which are a direct form of making money. Then some of them are able to sell information gathered from the app. If you look at the sweatcoin app that was popular awhile ago, it would track where you walked and would pay you for the amount of steps taken. On the surface this makes no sense as you don’t ever given them any money but the information gathered that they would be able to sell would be able to cover any cost of the app by many factors They could easily know what shop you walked into,what order you went into these stores, where you go to after leaving a store. This is just a small amount of information that can be gathered by some algorithms brilliant people are able to create."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bh4ga3 | Why do gaming laptops with discrete graphics, i7 processors, etc not seem to function as well as desktops with the same specs? | Technology | explainlikeimfive | {
"a_id": [
"elq5dmp",
"elpxwtz",
"elq6zc0"
],
"text": [
"Laptops sacrifice power for portability. Open up a desktop and there'll be plenty of room left over. Open a laptop of similar vintage, and everything is crammed in, tight! The GPUs used in laptops simply don't have the room for the vast amount of VRAM etc needed for complex computations. They also have to be drastically more efficient, because laptops can't disperse heat nearly as well as a desktop can, nor do they have infinite electricity like a desktop does. Additionally, when looking at the specs, look at the whole picture (specifically the numbers, and their benchmarks). Not to be condescending, but just because two components share a name, doesn't mean they're the same. The manufacturers use terms like \"I7\" and \"GTX1080\" because they know those name evoke confidence, when in actuality, the ones being put in laptops aren't anything like the ones built for desktops. TLDR: Laptops components are designed to be compact and both energy and heat efficient; not powerful. Desktops only need to worry about power.",
"It probably has to do with the fact that laptops dont have a graphics card as big and as powerful as a normal gaming desktop would. Try playing a FPS on your pc without a graphics card... It runs like shit",
"The laptop i7 and desktop i7 are completely different chips, despite the name and generation on the label being the same. They are not the same. Yeah... marketing boyee! Anyways, the laptop chips are meant to operate at very low power consumption (and produce less heat), and thus are generally WAY less powerful than the desktops operating at full throttle and requiring huge heat sinks on the cpu because they are burning hot with all that power. Desktop cpus are designed for power. Laptop CPUs are designed to save power and be portable. This comes at a massive loss in performance."
],
"score": [
7,
4,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bh7kl8 | How can we measure blood oxygen saturation noninvasively but not blood glucose? | Technology | explainlikeimfive | {
"a_id": [
"elqkuxw"
],
"text": [
"Blood oxygen saturation is very easy to measure. You're looking at two *very* specific wavelengths of light, which corresponds to the wavelength at which the haemoglobin molecule absorbs light either with or without a bonded oxygen. Compare the two and calculate. Since glucose contains a whole bunch of bonds (C-O, O-H, C-H) which are everywhere in your body, specifically identifying glucose by its absorption doesn't work."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bha4dc | what makes a meat "processed" | Technology | explainlikeimfive | {
"a_id": [
"elr70oe"
],
"text": [
"Processed meat is any meat that is preserved by any of a number of methods, such as smoking, curing, salting, or addition of chemical preservatives. Examples of processed meat are bacon, salami, pepperoni, obviously bologna and hot dogs, most lunch meats, etc."
],
"score": [
10
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bhcyx3 | How is my Macbook Air able to play videos at 1080p up to 4K, with a screen resolution of 1440x900? | Technology | explainlikeimfive | {
"a_id": [
"elru5ye"
],
"text": [
"From wikipedia: > 1080p (1920×1080 px; also known as Full HD or FHD and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen vertically; Obviously there's not enough pixels for standard 1080p. However, computers can downsample images - basically, they simulate the larger screen, figure out what the best colors for the larger but less numerous real pixels are based on their location, and then shows that composite color instead. Say you had a screen that was exactly 1/2 the size of the video. Lets say that the four small pixels were like this: `BLUE | BLUE` `BLUE | RED` To compress that to a single larger pixel on the low-res screen, you'd make a color that's 75% blue and 25% red - a blueish purple. There are some fairly complex algorithms that map between larger images and smaller screens in such a way that it's visually appealing, but that's the rough gist of it. Edit: typos."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bhd9vx | How are online first person shooter games, like fortnite and pubg, able to transmit enough data between all the players, across the world, to keep everyone's games in sync? | It seems like that would be so much data (each players current position, direction, etc.) and would need to transmit and receive by all players so quickly to keep up with the players movements (which to an outside observer such as myself), seem super fast and chaotic. Add in high end graphics and fast framerates, it really does seem impossible that even with high speed internet infrastructure, those network packets are able to fly around the world and keep everything in sync. I just can't comprehend it. | Technology | explainlikeimfive | {
"a_id": [
"elrw059",
"elrw3vz"
],
"text": [
"All that's transmitted is player position and bullet position which can be put into teeny tiny data packets that are only kilobytes. Everything else happens locally on your computer.",
"Well it isn't really when you think about it. You've got the position of a player, the direction they're aiming, whether they're firing or not. Updated many times a second, no doubt, but that's...kinda essentially all there is? All the visuals is generated at your end, client-side to use the proper term. The information being transmitted is as you say just positions. When you consider network connections are fast enough now that you can stream 4K 60FPS video, a big pile of coordinates going backwards and forwards is nothing. I mean, back in the days Unreal Tournament was the king of multiplayer frag-em-ups a lot of people back then connected using dial-up, 56K connections, or 0.056Mbit, and it managed it then."
],
"score": [
16,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bhdipr | Why do some phone chargers work better than others? Is it the cord? The adapter? Both? | Technology | explainlikeimfive | {
"a_id": [
"els0umr",
"elry0qj"
],
"text": [
"Short answer, both. The adapters are usually rated 1A or 2.1A (USB is 5v). Most tablets and new phones use the higher 2.1A but some older phones will come with a 1A. Apple sell this as a fast charger when it's now mostly standard for phones. There are also custom adapters that have QI or dash charge capabilities. These use a variety of methods to get more juice in. Finally cables have ratings. Mostly a decent make will be fine and beyond that not much difference but a crappy one might only manage 1A.",
"Well, it can be both. But for the most part it all depends on the adapter. While certain cables can deliver higher levels of power(Such as USB-C), the bottleneck is almost always going to be the adapter that plugs into the wall. Some output more power than others. Usually measured in amperage because your standard USB is 5v. USB-C can support up to 20volts at 5 Amps which is far more than standard USB. But your device has to be able to support that much power."
],
"score": [
6,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bhh01r | How airplane windows tint and block out sunlight at the touch of a button and go back to being clear as if nothing happened. (Newer airplane models) | Technology | explainlikeimfive | {
"a_id": [
"elstmha",
"elsvzj7",
"eltnyr5"
],
"text": [
"Light can be bent and refracted or reflected. So there are layers to the window tint that allow the elements inside to change position to allow light(visible light)through, or to reflect it away.",
"Glass usually allows light to pass through, but an electric current moves atoms around in the glass, and they absorb light instead of letting it pass through, so the glass appears tinted.",
"~~~~~~~~~~ ~~~~~~~~~~ imagine that as two layers of glass, and now we put something that is attracted to charge in it ~~~~~~~~~ x x x x x x x x x x x x ~~~~~~~~~ x represents the charged particles. As you can see, if light enters, it can pass right through because there are gaps between each particle. Now press the switch, a current goes through one of the glass panels. The particle is now attracted to one of the glass panels. ~~~~~~~~~ xxxxxxxxx ~~~~~~~~~ No more gaps, no light can enter."
],
"score": [
6,
5,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bhj72j | What exactly is "loudness" in recorded music and why did the loudness wars occur? | Technology | explainlikeimfive | {
"a_id": [
"eltbmbe"
],
"text": [
"Loudness is simply the average volume of a music track. No matter how complex a song is, a digital file will store it as a single, continuous wave. In any audio file, there is a maximum volume that this wave can achieve. The wave can be any volume below this limit, but it cannot exceed the limit. This is where sound engineers run into a problem. Once the peak of the wave brushes up against the volume limit, you can't simply make it louder. Instead, you have to chop off the peak of the wave so you can amplify it. The more you slice off the top, the more you can make the rest of the song louder. Essentially, this makes the quiet parts of the song louder without affecting the loud parts at all, because they're already as loud as they can be. At first, you don't notice this because the \"loud\" parts of the song are actually instantaneous sounds like drum hits that only last a few milliseconds. But the more aggressive you get with the compression, and the louder you make the song, the worse it sounds. Eventually, you end up with the loudness wars, where songs are flattened out to sound as loud as possible while still being acceptable to the untrained ear. Here's an explanatory video: [ URL_2 ]( URL_1 ) If you want to hear the problem for yourself, I suggest listening to these two videos. Good version: [ URL_3 ]( URL_3 ) Bad version: [ URL_0 ]( URL_0 ) One is the original version of a Madonna song, and the other is the remastered version. Right click on each video, click stats for nerds, and look at the \"content loudness\" to see the difference. The remastered song is +6db, and the original is 0db, making the remastered version a whole 6db louder. In this example, the \"loud\" version has been deamplified to the same volume level as the quiet one, so it will be the same volume as the \"quiet\" version, but it still sounds much worse. The fidelity lost to compression can not be recovered. In particular, pay attention to the percussion. In the quiet version, the percussion is lively and stands out from the song. In the loud version, it is weak, and the bassline and vocals overpower it. The quiet, dynamic version of the song will make you want to tap your feet, and the loud version will force you to listen for the melody because the rhythm is weak and lacking."
],
"score": [
15
],
"text_urls": [
[
"https://www.youtube.com/watch?v=4OmRYcSw-O8",
"https://www.youtube.com/watch?v=3Gmex_4hreQ",
"https://www.youtube.com/watch?v=3Gmex\\_4hreQ",
"https://www.youtube.com/watch?v=SOhJHS7Rvrg"
]
]
} | [
"url"
] | [
"url"
] |
|
bhkdxl | How is 32 bit able to handle 4gb of ram, if 4,294,967,296 is the number of bits? | 4294967296/8 = 536870912 bytes 536870912/1024 = 524288 KB 524288/1024 = 512 MB 512/1024 = 0.5 GB If you divide it directly by 1024, you do get 4GB, but that number is the amount of data you can have in 32 BITS, so wouldn't you need to convert it to bytes first. | Technology | explainlikeimfive | {
"a_id": [
"eltioxf",
"eltiwqa"
],
"text": [
"32 bits is able to handle 4294967296 Bytes not Bits. The issue is being able to write down a unique address for each Byte in just 32 bit of ram. The CPU needs to address each byte in memory with a unique 'name' and it has only 32 digits to write down the name. It is a bit like writing down your street address and only having enough room for two digits for your street number. That would mean you only could differentiate between 99 different houses per street. If you have 3 digits for the street number you could have up to 999 different houses per street and so on. You don't need to address each individual bit in a byte in memory anymore than you would put down the room the person you are writing a letter to sleeps in (unless you send them a message per owl of course).",
"CPU's don't operate on individual bits within RAM. They read and write entire bytes, and that's why bytes are the ones with memory addresses that the CPU has to work with. With a 32 bit memory space you can give a unique address to 2^32 bytes of 8 bits each, for a total memory capacity of 2^32 * 8 = 2^(32+3) bits = 2^35 bits = 4 GiB (that's gibi**by**tes)."
],
"score": [
17,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bhn8vv | how is it possible to put together those 3 extremely small lights in a pixel? | Technology | explainlikeimfive | {
"a_id": [
"elu63vs"
],
"text": [
"It is done with photolithography. They use precision masks to project the tiny circuits onto silicon chips. They are even smaller in LCD projectors, but they are huge compared to the circuits used in microprocessors. Those are so small, they need to project the circuit patterns with ultraviolet light with a wavelength below 200 nm."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bhnubv | If cameras can take videos with fps equaling single shutter speeds, why do photographers take dedicated still shots instead of video recording everything and later just isolating single frames for “photographs?” | Technology | explainlikeimfive | {
"a_id": [
"elu8wt0",
"eluecr0"
],
"text": [
"In some cases you can, but when you take a single frame you have more control over the light. When you take a photo you can balance the depth of field, aperture size and iso- getting the right ratio of the three can give you much needed control in certain scenarios. When you record video- most of those settings become automatic so a lot of work might be needed in post production to get the shot you need. I’m sure with more expensive technology you can do it easier, but basically the needs for photos and video are not the same to produce an image.",
"> If cameras can take videos with fps equaling single shutter speeds, That assumption is not correct. The shutter speed is the time the sensor is exposed to light not the time to read out the captured information. A simple camera can capture image in 1/1000 of a second but that do not in any way mean that it can take 1000 pictures per second. It take time to read out the images from the sensor so you talk of single digit number of images per second for most camera. Cameras cant take video at a high fram rate in the same resolution as they can capture a still image. It take time to read out the image from the sensor so you have framerate vs resolution limitation for a sensor 4K video is 3840 \\* 2160 that is only 8 mega pixel and 1080P is 2 mega pixel For example a Nikon D7500 DSLR with a 20 mega pixel sensor can do 4k video at 30 FPS and 1080p at 60 FPS but at 20 mega pixel it can only do 8 fps and if you put it in continuous mode it will do that. & #x200B; A more expensive and complicates setup might be able to capture 20 mega pixel at 30 FPS but than is also can do 4K at higher FPS. So filming video at the same resolution as a still image is simply not at cost efficient. Burst more or continus mode is avalible at the camera and they produce images as fast as posslible and that is a common way take pixture"
],
"score": [
9,
7
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bhqf7t | If I try to simultaneously charge my phone with a cable and a wireless charger, will it charge quicker than it would with only one of these? Why or why not? | Technology | explainlikeimfive | {
"a_id": [
"eluwvvz",
"eluwm4p"
],
"text": [
"[Here's an article]( URL_0 ) that tested that. The short of it is no, it doesn't make it charge any faster. Why? generally phones only have one charging circuit/controller, that is, once it hits its charging peak from a source, which is generally enough from a single source, its not charging any faster, its already going as fast and best it can. Though I don't know how it would work from two sub-optimal sources, but I suspect it will simply charge from the \"best\" of the two sources.",
"It won't charge any faster. The phone's charging circuit is what controls charge current. Neither the cable nor the wireless receiver is connected directly to the battery."
],
"score": [
7,
6
],
"text_urls": [
[
"https://birchtree.me/blog/what-happens-when-you-try-to-charge-your-iphone-wired-and-wirelessly-at-the-same-time/"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
bhuz5j | How do people remove the vocals from a song and leave the instrumental part completely intact? How does a computer know which sounds are someone’s voice and how to isolate them from the music? | Technology | explainlikeimfive | {
"a_id": [
"elw00zc",
"elw2ide"
],
"text": [
"Usually the instrumental is released as a separate track by the studio. A computer can't remove vocals perfectly, so while it is possible, you'll still hear traces of the voice, and the instrumental will be distorted.",
"I have some hobbyist experience creating and using acapella and instrumental tracks. Professional tracks are layered during production. That is, each instrument, the percussion and the vocals, are distinct from one another, and added together to form the complete song through mixing. Finished music contains a ridiculous amount of effects, volume variations and equalization tweaks to create the desired sound. The quality of product wouldn't be possible if the channels weren't discrete, and altering one altered the entire track. \"Studio acapellas\" (vocals only) are simply the original vocal channel of the song, before it was mixed into the final track. They're the best quality, and completely free from any noise (unwanted sound). Instrumentals are the same, they're simply the original, isolated channels before they were integrated into the whole. You *can* try to isolate one or more element from a complete track, but it's painstaking and ultimately flawed. No computer can precisely remove the element you want; once the elements are merged, the frequencies merge, and trying to remove a singular element will always cause you to either take similar frequencies that weren't part of the element before mixing, or lose parts of the element in order to cut out noise. This is why a lot of \"post-production acapellas\" sound tinny and hollow; because the person who isolated it narrowed the range to cut out noise, and lost frequencies from the original vocal track."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bhwk5y | How does a VHS tape work? | Technology | explainlikeimfive | {
"a_id": [
"elwbr6g"
],
"text": [
"The black tape inside the cassette is magnetic. By running it past a recording head, you can rearrange the magnetic stuff. Then when you run the tape past a reading head, it reads that signal and sends it to a processor that converts it into audio & video output."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bhwp0w | The photoelectric effect | Technology | explainlikeimfive | {
"a_id": [
"elwiuo1"
],
"text": [
"Imagine you want to open a very tightly sealed cookie jar. Try as you might, sometimes it's just impossible for you to open the cookie jar if you can't produce enough strength to just twist it past that first bit. You could spend forever trying, but it just won't happen. Now, if something or someone could come along and provide that initial burst of strength to loosen the jar first, then you'd be able to open it. The photoelectric effect if similar to this, except with light and electrons. To imagine this, we'd first have to assume that light can act as particles in addition to it's normal wave nature. In other terms, every wavelength (read: color and/or type of energy) has its own specific bursts of energy so essentially, when you shine light at a metal, the light is applying bursts of energy to the metal in trying to remove the electrons in said metal. Now, the metals don't want to give up their electrons. In fact, every burst of light that tries to remove said electron would have to be strong enough to overcome that attraction between the metal and its electron. If that light happens to have the minimum required energy, it'll be able to remove said electron, with no problems, like opening a cookie jar with enough strength. However, if that light doesn't have enough energy (remember, try to imagine light as bursts of energy, so each burst doesn't have enough energy), then you could shine that light all day, and it would never be able to remove any electrons from that metal."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bhwz15 | Why is there an "accept" box on websites explaining they're using cookies, when they're going to use cookies anyways whether or not you hit the accept button? | Technology | explainlikeimfive | {
"a_id": [
"elwf14k",
"elwjdux",
"elwkfof",
"elwe8hq",
"elwllhh",
"elwj5kh",
"elwirzb",
"elwji2u",
"elwpi7g",
"elwmsvu",
"elwn9xv"
],
"text": [
"Because under current European Union laws websites have to warn you they're storing data about you before they do it. If they didn't tell you and tracked you, you could then sue them for monitoring you without your permission.",
"Can confirm that -- at least for our organisation -- our website doesn't keep cookie data on users unless they first accept the popup. When we enabled it for GDPR we saw a 70% reduction in traffic visibility for a few months.",
"There’s two problems with most sites: 1. They are given bad advice from their teams. Most people have not read any of the legislation, they don’t actually know what they can and cannot do, so they implement it poorly. 2. Most sites that rely on advertising for revenue _want_ to make it confusing and annoying so you just press ‘Yes to all.’ A lot of sites implement GDPR and related cookies. They should not be adding any cookies that require permission until they have permission. Some do and some don’t. There’s three types of cookies. 1. The first is transactional cookies. You don’t need permission or need to even mention it, for example, when you sign into a site a cookie can be used to remember that you’re signed in. 2. The second is non-tracking but not required cookies. For example for using analytics or ‘previously viewed’. You just need to let the user know that these are happening. 3. The third is tracking, where the cookies follow you around to other sites. These you have to wait for permission from the user before you can add the cookie. So when a cookie banner pops up, they could already be using the first two but not the third. However, some sites implement it badly and do this incorrectly.",
"Basically they are just covering their ass. They don't really care. Some sites will close out if you hit no, but you make a valid point. It's stupid.",
"and why is there never a decline button? its hit accept of have banner blocking part of the screen the whole time you are there",
"I can't be the only person annoyed by the crap GDPR has created on websites now? Some of them have really elaborate opt-in/out windows, and actually take time to process your preferences, before you can view the content. Then you have to do it all again if you visit after the cookie has expired, or on a different browser, or device. You even find websites (mainly in the US) that outright block you now if you're coming from an EU IP address. The UX on websites nowadays is so degraded by this crap.",
"(This ELI uses GDPR) Normally, data processing requires the consent of the person. However, there is also something called \"legitimate interest\". Legitimate interest also acts as consent, that doesn't require a person to consent to data processing itself. That's why there is only an informational banner shown that does nothing. That and also because many website-operators just don't have a single clue on how to implement an opt-in system.",
"Here is my best ELi5; You go to the mall and there are 5 cookies shops all in a row. To thank you for buying a cookie, you get a fancy little name tag and if you wear it in next time, it already says what cookie you got last time. Now you have a grumpy German relative that thinks it’s a bad idea for strangers to know your name without mommy and daddy’s consent. Most of the time it doesn’t matter to your family but it is a good idea to be picky who can read your name tag. You can take off your name tag, and unless the baker has a suspiciously good memory they won’t remember you.",
"It's called informed consent. They're telling you that they're using cookies and giving you a chance to leave the site if you don't want that.",
"Some legit website have \"Do not accept\" button too. I wonder what happens if I click cross, does that mean \"Accepted\" or \"Not accepted\" in terms of cookies?",
"It's supposed to be that when you hit Cancel/Decline they only pass cookies that allow the site to be functional, at least that's what the people I work for do. If a user declines the cookies warning, we strip all the cookies out and only allow the ones that let them complete the user journey successfully. If you dis-allow all cookies a website can become unusable :/"
],
"score": [
2416,
304,
160,
59,
29,
12,
10,
4,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bi0rfb | Why do some automatic cars have a +/- manual transmission option, and what is the benefit of using it? | Technology | explainlikeimfive | {
"a_id": [
"elx4cc5",
"elx70x2",
"elxotd1"
],
"text": [
"It allows a person to manually shift the gears, which has been a common thing for many decades. This can be useful for shifting to lower gears when doing things like going up or down very steep inclines. Also some people like to \"play\" manual sometimes :\\",
"When you are driving enthusiastically on an interesting road, you want to 1) slow down for the corners, 2) adjust your engine speed so it's at the right RPM, and 3) accelerate out of the corner. You downshift as you enter the corner. That lets you use engine braking to control entry speed (in a rear drive car, it preserves front wheel traction that you'd otherwise waste braking). Engine braking accelerates your engine to the appropriate exit RPM (otherwise you'd waste horsepower accelerating the engine before you could get it to the wheels). It's more fun than just driving, and it's warmer and dryer than doing it properly on a motorcycle.",
"Older automatic gear boxes didn’t really have the concept of fixed gear positions and used very different mechanics to a manual gear box (e.g old torque converters), which are also quite inefficient compared to a manual box. Modern gear box technology (so called semi-automatics) are based manual gear box mechanics but controlled by a computer instead of the driver deciding when to change gear. With these you get the best of best worlds, and because the concept of actual gear numbers exist in these types of gear box, the driver is given the ability to override the computers decision of what gear to be in, and tell it to select a specific gear (e.g with the +- paddles). You’re not manually changing gear physically like you would in a true manual as gear selection is computer controlled, you’re just telling the computer what gear you want, whereas normally it’ll decide itself what gear is best at that time. Depending on the make or model, the software might decide your choice of gear is not a great idea and change gear anyway!"
],
"score": [
14,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bi0v2u | What actually causes the insane visuals in video feedback when you film a screen with the camera plugged into it? | [Here's an example of what I'm talking about ]( URL_0 ) There always appears to be these intricate wavy white, green, and blue lines that appear to expand infinitely. Does it have to do with the television's pixels, or the camera's sensor, or could it be more than that? | Technology | explainlikeimfive | {
"a_id": [
"elx69ip",
"elx8fcb"
],
"text": [
"Moiré patterns; essentially when you take a grid of squares and put it on top of another grid of squares, if you squish or move one you get these crazy pattens from the overlap. A camera sensor and tv pixels are basically both grids, so this is basically that effect but with color going on.",
"Stephen Colbert had a running gag in The Colbert Report where he would get his portrait made while standing in front of his portrait. After a few years, it had a similar look to pointing a camera at a screen the camera is outputting to. Basically, the TV is drawing a portrait of itself recording itself and then a portrait of itself drawing itself drawing itself, causing a hall of mirrors effect. The Colbert portrait for those who are interested: URL_0"
],
"score": [
4,
3
],
"text_urls": [
[],
[
"https://www.si.edu/newsdesk/releases/national-portrait-gallery-says-goodbye-stephen-colbert-s-portrait"
]
]
} | [
"url"
] | [
"url"
] |
bi14z2 | How do machines learn? | Machine learning has been booming lately and there was a lot of buzz around them. I would like to know how do machines learn from data or from themselves as stated by their creators. | Technology | explainlikeimfive | {
"a_id": [
"elx9hc7"
],
"text": [
"TL;DR Trial and Error So there are many different kinds of AI and machine learning algorithms, but the basic idea is the same. Programmers can solve a lot of problems, but some problems are just really hard and involve too many variables to efficiently figure out on our own. Things like how to make a robot walk, or all the variables involved in facial recognition. Instead, a program starts with some random configurations that don't work very well at all. But they're somehow told how they're wrong (depending on the exact method) and which general direction to adjust (this can include thousands of numbers that need to change). The next time the machine tries, it's just a little bit better. Given enough training, the machines can get pretty good. Of course, this training requires input for which we already know the output. For making a robot walk it's pretty easy, either it walks or it doesn't, or it walked a certain distance or cleared a certain obstacle. For facial recognition (e.g. determining if 2 faces are the same) we can take a bunch of images of faces, some are of the same person and some aren't, and either the machine correctly identifies they are/not the same or it's wrong."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bi2quc | Why do films and TV shows look weird and low-budget on some modern TVs? | Technology | explainlikeimfive | {
"a_id": [
"elxkyxc",
"elxula0",
"ely02r8",
"ely6mx3"
],
"text": [
"What you could be referring to is what some TVs call \"enhanced motion\". It is a technique that can make older TV shows look like they are filmed at a higher frame rate. The motion looks different and the way it looks is something we have most strongly associated with cheap consumer cameras and low-budget TV shows. & #x200B; Some TVs are so bad that the the look seems to turn on and off inside the same scene. These new TVs allow you to turn the feature off. The next time you are at friend's house and you notice this, ask if they can turn it off to see if it goes away.",
"I’ve noticed this on HD TV’s. I think we are used to seeing TV shows in low quality which sort of blurs out the details of the sets and the actors’ faces etc. When we actually see all those details in high definition it gives you a weird feeling like you are watching actors on a set, like you are more aware that they are real people or something. To me it makes it look low-budget. I’m not sure if this is the effect that you are noticing but this is just something I have noticed and it’s why I don’t like HD TVs.",
"It’s called the soap opera effect. It is really annoying that some people don’t notice/care. Please switch off all post processing on tv’s it just degrades the picture quality.",
"It's automotion/trumotion/motionplus, its usually in advanced picture settings, turn it off. Usually on by default from factory. I've literally never met a single person that liked the way it looked."
],
"score": [
33,
9,
6,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bi2vm5 | Why do software needs people who gives maintenance software once it's running? | In a software company what do software developers do after the app, for example, is done? Why is there a need for a whole team of dev's having a full time job? | Technology | explainlikeimfive | {
"a_id": [
"elxlcea",
"elxogbj",
"elxovah",
"elxo94j",
"elxtqej"
],
"text": [
"Mainly for the implementation of new features or solving bugs. Even though we run extensive testing before deploying a final product, there are always \"corner cases\" that can bring up unexpected behaviours on a site/app/system.",
"> In a software company what do software developers do after the app, for example, is done? They fix bugs, they implement the next version, they fix bugs, they implement changes due to changing laws ore regulation, they fix bugs, they react to changes in the digital environment in which the software operates (server software gets updated, your code may be incompatible with the new version, security holes may be discovered, partner websites may go out of business, your own websites may change their address, a service your software uses may change its interface, ...), oh and did I mention that programmers have their hands full fixing all the bugs that management knew about before the release date but decided to ship the product anyway? > Why is there a need for a whole team of dev's having a full time job? Maybe there is, maybe there isn't. If there are no new features to develop and if the software has been running smoothly for a while (and therefore most major bugs are already fixed), then there is probably only a reduced team of developers still on the project. In some cases the maintenance of the old products is done part time while the developers are already working on some other new project.",
"It really depends on your definition of \"done\". Technically, a software is done when you pull the plug on it. Think of Windows XP, for example. Even if tomorrow the biggest Windows XP flaw ever was discovered, Microsoft probably wouldn't fix it. So, Windows XP is done. You might think \"done\" as in delivered. When a software is given to a client fit the first time, it is rarely finished. There are often many new features that need to be added and a billion bugs to fix. If the software is supposed to be used for a long time (think 15,20,30+ years), some pieces of the software might be shit. In that case, developers need to \"refactor\" them, which means cleaning it up to make it easier to maintain. In this case, the developers will be working on this. Most of the time, when a software reaches a certain point, the development team will be reduced, because there is not much to do. The developers will be placed on another product. If you want to know why there is a need for many people to work on bugs after a software is \"done\", it's because softwares engineering is a pretty new field and we are mostly kind of bad at it ahah. With time, best practices emerge and software gets better but there is still a lot to be done.",
"Devs continue to fix bugs in the software and enhance it for further needs. Not to mention, when a product is done they don't just fire all the devs. The devs get put on new projects.",
"Anecdote time. I was hired as a maintenance dev at a large company and placed on a project that had launched just a few weeks prior. The code was bad, like, really, really bad, like, 'people got paid to write this?' bad; but, it worked, in the most basic sense of working, most of the time, if the data wasn't particularly challenging that day. (it was a batch job that ran once every 24 hours) Over the next few years, it was my job to polish this massive turd, but I couldn't just rewrite the thing so it would work correctly, be maintainable, be testable, no, I had to address defects and only work on the code that was affected by the complaint. This was because there wasn't any automated testing implemented and the business partners wanted to do the least amount of manual testing possible, understandable, but, ffs. As I learned more and more about the app, I became more and more appalled. I learned that the entire team of developers that had made it were long time COBOL programmers that had been sent to a Java bootcamp and then set loose on the requirements that made up this thing. It showed. The entire thing was written as if it were COBOL, but using the Java language. I'm sure there are more elegant ways to control logic flow in COBOL, but due to their inexperience with Java(?) they just nested if within if within if within if. There was more than one class that had a nested if quagmire that stretched over 1000 lines. \"Oh, dear, this entire poopstain seems to be the root of the problem and it all needs to be rewritten, aw shucks, guess I'll just have to refactor it, add logging and testing, darn\": Me. So, I could go on, but, meh, one last thing I'll mention: there's never enough time to make the app you want to make. In this app's case, they had been plowing through it when, all of a sudden, the company had a falling out with the third party vendor the app had been tasked with interfacing with in order to do the thing and the company spec'ed in another vendor, a week before it was due to go live. Of course, the new vendor had an entirely different interface and needed the data in an entirely new way. My boss was super proud that the team was able to meet the deadline anyway. I didn't find this out until I was on my way out the door, but it explained something: I had always wondered why they designed it in such a way that it resembled a stereotypical closet full of garbage, forced closed, off a living room, that for some reason had a tub in the middle of it, which had bare wires running through it. Knowing didn't help, but at least I had a better understanding of why. But let's say an app was perfect: perfectly designed and implemented and worked perfectly out of the box. There would still be a need for devs to update it, add new features, make it handle new security threats, make it work on new platforms and equipment, and on and on."
],
"score": [
35,
16,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bi41zd | What is physically happening when a file gets deleted, and how is it physically stored anyway? How is the file still stored when the PC is off? | Technology | explainlikeimfive | {
"a_id": [
"elxvca1"
],
"text": [
"When a file gets deleted, it's still there it just has a flag applied to it to say that that space can now be used. Think of it like a car park. If a car (file) is in a space, it's there. Deleting a file just means a tarp is thrown over that car with the understanding that, if the space is needed, the car will be removed (it'll be overwritten). As soon as the tarp is there, the space might as well be empty. But it kinda isn't. That's why files can be recovered when they're deleted. You can get a special program that goes around and pulls off the tarps restoring the files. The way you delete files properly is by 'shredding' What happens then is the file is deleted, and random data is written over the same spot again, deleted, re-written, so there's nothing to recover. Even if the tarp is pulled off, there's nothing of any sense left there to retrieve. On a hard drive the data is stored magnetically. There's a physical disc inside, made of metal, and there's a head that magnetises areas of the discs in a pattern which when read, converts back to data. Magnetism persists without power, so that's how the data is held. With solid state storage (an SSD), the easiest way to think of it is there are a bunch of electrical switches inside, transistors, which can be either open or closed, and they're what's called 'non-volatile' that means whatever state they're in, they'll stay in whether there's power there or not. There are millions of these switches, and depending on the pattern they're switched into, that can represent data. I realize this is being very vague indeed, but it's a subject that would rapidly jump out of ELI5 territory if you went into the nuts and bolts of it."
],
"score": [
39
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bi4pn9 | anti aging techniques | I recently saw month nicole Kidman in aquaman and Michelle pfeifer in antman and was impressed by how young they look. What sort of techniques does the modern wealthy person use to reduce aging? Stem cells? Blood transfusions? Or is it just improved plastic surgery? | Technology | explainlikeimfive | {
"a_id": [
"ely73dp",
"elxzv9g"
],
"text": [
"As a photographer, please don’t underestimate the power of professional set lighting that you’re seeing on screen. You’d be shocked at how much effort and equipment goes into lighting a scene. Supposedly, Barbra Streisand would bring her own lighting people anytime she would appear anywhere professionally.",
"Lots of Botox and plastic surgery I’m sure. People did one of those spreads in celebs who don’t drink alcohol a few years ago and I remember being blown away at how young they all looked... Jennifer Lopez, Blake Lively, Rob Lowe. Personally, I’m okay trading wrinkle free skin for beer."
],
"score": [
9,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bi5swv | How do radar detector-detectors work? | If the radar detector is passive, how can cops know that you are using a radar detector? | Technology | explainlikeimfive | {
"a_id": [
"ely9djx"
],
"text": [
"Because it is not 100% passive. In order to detect the radar, the signal being received by the antenna is mixed with a signal from inside the radar detector called a \"local oscillator\". The signal from the LO can be received for a short distance outside the car. & #x200B; For a bit more information, google \"Superheterodyne receiver\" for information on local oscillators and mixers."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bi5tbm | Why is it that certain character cannot be used in the naming of files on Windows computers? | The characters that are disallowed are: \\:/\*? < > | | Technology | explainlikeimfive | {
"a_id": [
"ely8u5k",
"ely8zhk"
],
"text": [
"Back in the days of MS-DOS (Microsoft Disk Operating System) those characters were used in the command line for telling the system what to do. Changing a to a tree in the directory was something like 'cd c:\\Reddit Been a long time, but that's close.",
"Mostly for DOS reasons. Windows isn't built on top of DOS anymore and hasn't been based on a command line for years now. But a lot of those details still exist in the way it's built, and this is one of those cases. Those characters all either had purposes in DOS or still have purposes now and so can't be used in in file names. \\ designates separation of folders (same reason you can't use / in Linux file names), / is used as a switch in command line, : designates drives, * is a wildcard character, and so on. Allowing their use in file names would fuck up the way the OS parsed what you types."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bi8hbd | How is a surge protector able to tell me if it is properly grounded? | It has its own little green indicator that actually tells me if it is connected to ground. If ground is not present the light is off, when present it’s on. I just want to know how it knows, and I imagine it has something to do with feedback or resistance measuring. | Technology | explainlikeimfive | {
"a_id": [
"elyswig"
],
"text": [
"By checking for continuity between the ground pin and neutral pin. If no continuity exists then ground does not exist. Ground wires and the neutral wire both end up in the same place inside your circuit breaker panel."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bib26r | How can a controller only control its own RC car if they are mass produced? | Technology | explainlikeimfive | {
"a_id": [
"elzdb1y"
],
"text": [
"In the old days of FM and AM radios, it was tricky. For RC aircraft, the 72MHz band was divided into 49 channels. Each radio would be given a crystal that was tuned to one of those channels. Obviously when you're making millions of the things, and there's only 49 channels to chose from, they're going to have to duplicate. Problem is that if someone on the same channel as you turns their radio on when you're flying, the receiver in the plane will get confused, and your expensive model is likely going to get lawn darted. Most AMA/MAAC sanctioned flying fields had strict frequency management rules as a result. Radios were to be kept in an impound shed when not in use to avoid accidental switching on. Frequency management boards were used to show what channels were available, and what weren't. But there was still room for human error, and accidents still happened. Those radios were also really prone to environmental interference. Around about 2006 or so, Horizon Hobbies introduced the first \"spread spectrum\" radios, that ran at 2.4GHz. A controller would be binded (paired) with the receiver in the plane, much like you would with a Bluetooth device. Once that's done, the radio automatically scans for available frequencies, and locks in to a free channel. If there's any interference, it can \"hop\" to another free channel, ensuring the model always has a stable connection with the controller, as long as there's power. A failsafe mode is also built in that keeps the model flying straight and level until it can reconnect, should there be a major issue. Thus taking out any possibility for human error. Spread spectrum has become the standard now for almost all radio controlled models."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bicr24 | How can a documentary like "Our Planet" record such high quality audio on animals from a far distance? | Technology | explainlikeimfive | {
"a_id": [
"elznbkp",
"elzu7ny"
],
"text": [
"It’s dubbed in. They have a studio that just does sound effects. There is a guy in a room with a bunch of junk around him and he plays it like instruments. Edit: here is a YouTube link [YouTube ]( URL_0 )",
"That's why I prefer watching older documentaries when I want to see \"more realistic\" scenes of animals and nature. It's less dramatic in terms of cutting, story telling and of course in terms of dubbing why a lot of people find it rather boring. However, I don't wanna bash modern documentaries, I also like them, but the sound is so over-realistic that it's like watching a movie that showes sort of an interpretation of the world."
],
"score": [
12,
3
],
"text_urls": [
[
"https://m.youtube.com/watch?v=Li6TSwybqjU"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
biekdq | How do breweries/bottling companies bottle their foamy products e.g coke, beer without it foaming up since when you do the reverse, it foams up? | Technology | explainlikeimfive | {
"a_id": [
"em018ve",
"em01hk3"
],
"text": [
"At least for homebrewing, the beer goes into the bottle flat, and then gets carbonized in the bottle. There's no head (foam) because there's no co2 to make it until a few weeks later.",
"Best way to answer is to show you. & #x200B; [ URL_0 ]( URL_0 ) & #x200B; Start at about 29 seconds. You can see it does foam up, but they put the cap on very quickly."
],
"score": [
3,
3
],
"text_urls": [
[],
[
"https://www.youtube.com/watch?v=ekPrFT5nPvg"
]
]
} | [
"url"
] | [
"url"
] |
|
biimvz | Why does AM radio broadcast travel so far at night? | I live in Texas and at night, I can pick up AM radio stations broadcasting from much further away than I can during the day. Like, right now, I can hear a station from Chicago. Why? | Technology | explainlikeimfive | {
"a_id": [
"em0x2mn"
],
"text": [
"From what I understand, the signal bounces off the ionosphere and can, with a strong enough signal, travel around the whole planet. URL_0"
],
"score": [
9
],
"text_urls": [
[
"https://youtu.be/_VDUGiJhK78"
]
]
} | [
"url"
] | [
"url"
] |
biqx14 | how do speakers play more than 1 sounds (like 2 voices and music overlap) at once? | Technology | explainlikeimfive | {
"a_id": [
"em2d7js",
"em2imny",
"em2iwmn"
],
"text": [
"All sounds are made up of waves, and if you add waves together, you get a single wave that incorporates everything that made up the constituent waves.",
"Think of it like mixing colors. We all know that red and blue make purple/violet. That's a distinctive color from mixing blue and yellow, which makes green. What I'm saying is that we can tell the difference between things that are mixed together. Colors are just like sound, they're waves of photons, and sounds are waves of air pressure. These waves can be mixed together.",
"Sounds are waves, but the sounds we hear are not pure waves of a single frequency like you see in a book. There's various influences that contribute to the end result, basically a bunch of waves added together. This is why you can tell an \"A\" on Piano from an \"A\" on Guitar, or an \"A\" on violin, despite all being a string vibrating at the same rate. The base frequency is the same, but all the other contributing sounds are added together to produce a unique result. The vibration of the body, the reverberation of the air inside, etc. Everything makes sound, and it's the sum total that we recognize. Instead of a [neat pure wave]( URL_1 ), [we get a jumbled mess.]( URL_0 ) (That particular picture is a Violin, playing \"A\" (440hz), showing the difference in sound between a plucked string and a bowed string.) Quite simply, the speaker replicates that jumbled mess, directly. The speaker follows that same path, replicating the end result. As more instruments or voices are added, that jumbled mess gets even more complex. There is certainly a limit where it gets so complex it's just \"noise\", but, the speaker is still just outputting the \"sum total\"."
],
"score": [
11,
3,
3
],
"text_urls": [
[],
[],
[
"https://i.imgur.com/89NBgZ2.jpg",
"https://upload.wikimedia.org/wikipedia/commons/thumb/7/77/Waveforms.svg/1200px-Waveforms.svg.png"
]
]
} | [
"url"
] | [
"url"
] |
|
bir4eq | what are atomic clocks and how do they work? | Technology | explainlikeimfive | {
"a_id": [
"em2fmjh"
],
"text": [
"When electrons are excited (given a little more energy) they tend to release it eventually and go back to their low energy state. The time for that to happen is very predictable in certain gases. An atomic clock works by exciting an element like hydrogen, cesium, or rubidium and detecting what frequency waves are emitted or absorbed by the gas. They then divide that frequency by a known factor to get a stable clock at 10 MHz. That can be divided further into one second increments."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bitpx8 | how does the national grid work? How can my energy supplier say that all my power comes from renewable sources? | Technology | explainlikeimfive | {
"a_id": [
"em3akm0",
"em3tyog",
"em2zv52"
],
"text": [
"So let's say you and other users who want renewable energy consume X units of energy. The grid may have both renewable and non-renewable sources, but as long as they buy/produce X units from renewable sources then they can say that your power was renewable.",
"Everyone assuming op lives in the US :) The exact answer will depend on which country you live on, but typically they cannot guarantee that all your energy actually comes from renewable sources, because the grid is shared between all operators and you can’t separate each operator’s energy. What they do can guarantee is that all the energy they buy comes from renewable sources.",
"There is not a single national grid in the US. There are local grids maintained by local suppliers that are connected to each other to form 3 major regional grids in the lower 48, Western US, Eastern US, and Texas (Hawaii and Alaska are also independent but considered to only be local grids as the islands and cities rarely connect to each other). Each supplier knows what sources they use to produce their energy and if they only use renewable resources such as solar, wind, geothermal, or hydro-electric then they will tell you such. Local grids can share with neighbors, and to some extent across the whole regional network, but the regions do not share with each other."
],
"score": [
4,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bitr3a | Why are so many sniper rifles still bolt action? | I am not very well informed regarding how many current military sniper rifles are bolt action, but it seems like any number greater than 0 is too many. Why is a gun that requires a relatively lengthy hand motion for each bullet still used, when magazines or clips prepare the next bullet automatically? | Technology | explainlikeimfive | {
"a_id": [
"em3cblz",
"em2ytjz",
"em2yvdu",
"em307gr",
"em33vor",
"em32do7",
"em31ebz"
],
"text": [
"I'm surprised no one has pointed out the most important reason yet. When a bullet is loaded from a magazine, either through an automatic or a bolt system, it is pushed up a feeder ramp into the breech. This ramp, and being slammed into the breech, can leave imperfections in the round, or in the brass around it that, to a shooter, make the difference between a kill and a miss. Since critical rounds are hand-loaded and well-checked for imperfections, shooters prefer to place the round by hand into the breech, which is accomplished *much* more easily with an open manual bolt than an automatic bolt. Even bolt-action rifles with magazines are almost always ever loaded with one round at a time for critical shots. Source: Drive an M24 professionally and have never had more than 1 round loaded at a time.",
"They are more reliable than auto. Also snipers typically only take 1 shot at 1 target at a time.",
"Generally speaking, a high rate of fire isn't the biggest concern with snipers. The bolt is mechanically simpler, and the recoil is going to require at that distance that you readjust after each shot anyway.",
"Bolt action is typically more accurate, and more reliable than semi-automatic. There's just simply less going on here to break. There's also the idea that automatically ejecting your cartridge can give you away. Don't forget, a sniper needs to remain invisible. & #x200B; That being said, MANY snipers do use semi-automatic rifles. The M-14 is still used (it's been reworked), a variant on the M-16 that fires 7.62mm rounds is used, the barret m82 is semi automatic as well. A sniper will use the weapon system that lends itself to the situation. & #x200B; Side notes: Magazines are used to store and feed ammunition in a firearm, many bolt action rifles use magazines. A clip is used to quickly reload a firearm (or keep your chips fresh)",
"As others have said, reliability and power. Also, I've heard some former marksmen say that the bolt action allows them to carefully extract the spent cartridge from the rifle. Where as with semi-automatic, the cartridge is thrown out of the rifle after firing. I doubt this is an important reason, but it's a small benefit I guess; Having control of the spent cartridges.",
"Sniper rounds have a lot of energy in them, and that means that a human will take several seconds to get the rifle pointed at the target again. The time to cycle the bolt doesn't really add much. Firing a second bullet before the first round has hit is just guessing. With 3 seconds of time of flight, 20 rounds per minute is the fastest you'd ever be able to fire. That's 2% the rate of fire of an M16 in cyclic.",
"To hit a target far away you need a weapon that behave in a repeatable fashion. A manual bolt can be made to lock with less variation each time. Exactly the location of the cartridge in the chamber compared to where the barrel start will be important. Another part is that a automatic weapon need to use the energy to cycle. For rifles it is today almost always that you let some of the gass out of the barrel and push on a gas piston. There will be some variation is the amount of pressure that go out that way so the speed of the bulles vill not be as consistent so the speed of the bullet will have more variation then in a bolt action. The extra part that is attached to the barrel in the gas system will also make it harder for the barrel to vibrate in a constant way. Most sniper rifles today have a free-floating barrel that only is attached to the receiver and not anywhere else. So with the same manufacturing technology a bold action rifle is more accurate then a semi automatic rifle. Bolt action system is also lighter and more reliable then automatic system. So if accuracy is the main goal and rate of fire is a secondary bolt action is better for the same reason hunting rifles are most of the time bolt action. Bolt action is not that slow if you are in a prone fire position with a supported gun and aim carefully at a target. It is the aiming that take time and you can do that while you cycle the gun. It is a larger difference if you fire a gun standing."
],
"score": [
17,
13,
9,
7,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bix0up | What is the process for creating cgi effects on the scale of something like the battle for Winterfell where there are so many individual moving objects? | Technology | explainlikeimfive | {
"a_id": [
"em3ucqd",
"em48ojt",
"em41hka"
],
"text": [
"I can think of two techniques that are typically used high character count scenes. 1. Duplicating actors through a process called **rotoscoping (think copy and paste)** multiple times in the scene. This works best for characters with similar appearances like the Dothraki Horde or the Unsullied. 2. CGI Studios can make use of specific plugins in Maya that can **simulate large groups of people using the same technology to simulate fluids or particles.** This cuts down render time and means that animators don't have to animate each individual person/object. This is particularly useful for something the wights. An example of where this type of technique is used is in war games like Total War.",
"Make it dark and cover the whole thing in fog and do rapid quick cuts so you can't tell what's going on. Just kidding I love game of thrones",
"It's not easy, but it's not nearly as hard as it used to be. It's called digital crowds and there's a few pieces of software designed specifically for it. (Massive, Golaem, Houdini Crowds...) Basically, each actor is set up like a video game NPC with a handful of animation cycles that are driven by an AI to interact with the world around them."
],
"score": [
25,
15,
7
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bizc76 | how do you get color from a black and whitE photo? | Technology | explainlikeimfive | {
"a_id": [
"em48gmi",
"em4gnva"
],
"text": [
"It's manually coloured or a computer figures out the most likely colours. A lot of world war documentaries do this.",
"They basically take an educated guess when recoloring a photo. So \"what makes the most sense\" but sometimes also \"what message do I want to convey?\". If it's a sad/ tragic picture most people will use more muted colors compared to a happy scene from a family afternoon."
],
"score": [
8,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bizhw3 | Why do artists performing on stage need in-ear pieces? | I've heard that in-ear pieces help the artist hear themselves better, but why is it necessary? Audience members can hear the artist fine, so what changes on stage? | Technology | explainlikeimfive | {
"a_id": [
"em4b9bt",
"em49qfa"
],
"text": [
"Speakers are typically pointed towards the audience, not the performer/artist. If you point speakers at the performer, they’ll play into their mic, the sound will come out of the speaker, the sound coming out of the speaker will play through the mic, *that* reproduced sound will playback through the speaker, which the mic will...you get it. An endless loop results, this is called feedback. That squeaky riiiiiiiiiingiiiiiiiing sound you hear when Bobby stands nervously on the stage for his spelling bee, is feedback and should always be avoided. You can direct all your speakers away from the performers, however the performers need to hear themselves too. So, in order to reduce feedback you can use monitors, which are smaller speakers that direct sound close to the ground (away from the mics on the stage) or you can play the mix back to the performers through ear pieces. Even if feedback wasn’t an issue, another reason to use ear-pieces is that sound is awfully fickle. Sound bounces off walls, is absorbed by materials (and people) and can be reflected in all sorts of crazy ways. Playing back the “pure” feed to the artist helps them gauge their performance as they perform and ensures that what they’re hearing is what their audience is hearing. One last reason a sound engineer may want to use ear-pieces is that they can control what the audience hears versus what the artist hears. If you have a multi-person band, the drummer and guitarist may have different preferences on what they need to hear. A sound engineer can playback a mix that is specific to each member of the band so the members can better coordinate timing and tempo with each other.",
"To perform well, artists need to hear what comes out of their mouth and correct what was wrong a secind ago. Try writing without looking, and you will see how hard it can be to write nicely. So when you sing in a normal room you only hear yourself, but when you are on the stage there is also music, which is loud and speakers are in the direction of audience, what makes sound sound distorted for people on stage. There are sometimes speakers in the direction of artists, or thay have ear pieces."
],
"score": [
40,
10
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bj29hq | How does PWM (Pulse Width Modulation) work? | Im looking to get into Arduino and frequently see the term PWM used in projects that use Arduino but with an extremely basic knowledge of electronics i'm finding online explanations difficult to understand. | Technology | explainlikeimfive | {
"a_id": [
"em4qy13",
"em583yu",
"em4qs08",
"em55u4i",
"em54tfw",
"em4suki"
],
"text": [
"It's like playing with a ceiling fan switch: the speed of the fan is not going to drop instantly down to zero the instant you turn the switch off, nor is it going to get to max speed the second you turn it on. So, using this delay, you can switch it on and off, on and off, making it faster or slower, to make it go the speed you want at the time you want. (Dammit, driving was a much better example but oh, well.) Suppose you want the current delivered to a component to be in the form of a particular signal (maybe a sine-wave of so-and-so frequency, or going up then down, etc.) But the only control you have is to switch the power supply on and off. You can switch the supply on and off very fast, in a pattern, rapidly sometimes and slower other times, to effectively controlledly 'push' the average signal higher and lower in discrete steps as needed. The switching on-and-off is the pulse. The duration for which is the pulse is held is the pulse-width. And modulation is the function of all this: to end up with the signal you want.",
"Have you ever played video games with the keyboard or a D-Pad to move? If you want to run full speed you hold the button down. If you want to run half speed, you tap the button on and off so that it's down half the time and up half the time. Your character has some momentum so instead of going and stopping over and over they just move at a slower rate. That's PWM.",
"PWM is basically sending different *average* voltages over time when you only actually have one or two voltages to work with (like 0 and 1 in binary). For example, if you can only send 10 volts, and you need to provide 5 volts over 1 second, then you send 10 volts for half a second. The 'width' of the pulse is how long you send it for. I'm not familiar with arduino programming, but I imagine PWM is a way to send variable voltages using only a binary source, which is easy to code as long as your program/computer's timekeeping is good.",
"In PWM a transistor is used to rapidly switch a fixed voltage on and off, typically on a fixed but sometimes variable \"carrier\" frequency. The on time of the switch is the width (time duration) of the \"pulse\". The width of the pulse is set to different time duration's (modulated) to provide a percentage of the power that would be available if the switch was left on 100% of the time. For example if the switching occurs 10,000 times per second (10 kilohertz) and the width of the pulse is set to 1/5000 of a second, 50% power is delivered. For industrial motor drive applications the carrier frequency may also be varied to prevent harmonics with the stator, but the concept is the same.",
"Other people have explained what PWM is, so here's some basic things that it's useful for in the Arduino world: LED brightness: You can't* dim an LED; it's either on or off. So if you want to dim it, you need to make it flicker really fast. The longer that it's on each pulse (duty cycle), the brighter the LED is. *You can run LEDs at different brightnesses, to a point, but it's inefficient and you don't get a very good range. Better to use PWM. Motor speeds: By adjusting the duty cycle, you can change the speed of the motor. (Be careful, motors can draw a lot of current, and you can overload the output capacity of the Arduino.) Basic audio: There's a tone() library that extends the built-in PWM featured to let you control the frequency instead of the duty cycle. This can be used to generate basic square-wave sound output to a piezo speaker.",
"Look at a microwave oven. The thing is, you can't easily regulate power of a MW oven. So, what does it do when you set a lower power. Well, listen to it. You hear it humming for a while, then silten, then humming, silent and so on. That is what they do. If you, for example, set it to 75%, it runs (for example) for 3 seconds, the switch off the emitter for 1 second, and repeat this. This is PWM. Instead of regulating output finely, you turn it full on, then full off, and regulate the power out using the ratio between time on and time off. This is usually done for one or more of several reasons: * Thing is controlled by a computer, and computers like simple on/off. * Thing is hard to control finely, it's much easier to just go full on/off. For example, the heater in my house, which works on wood pellets, either burns as efficiently as possible, or is off. * The process you are regulating is quite slow. If you are, say, heating a house, there is an inherent slowness in the system, so it isn't noticeable if the control \"flickers\"."
],
"score": [
18,
9,
4,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bj5lns | How does a movie screening/license work in a movie theater? | Like, do they have a file on their device? For how long they can have that? Is there any limitation on how many times they can play it? How much they can keep from all the money the movie will make? | Technology | explainlikeimfive | {
"a_id": [
"em5w2vb"
],
"text": [
"Former IT on a movie crew here. Basically, to put it simply, the projector system is set up with a backend system that allows the movie distributors to provide digital versions of the movie to be premiered. The files are time sensitive, and will only be allowed to play once the time threshold is entered (skipping the computer's date ahead won't help, it needs to be connected to the internet to work) The files will still exist on the system after the time threshold is passed, but they won't be playable ever again. This is how mass distribution and prevention of premiere date breaking is achieved. Reels aren't shipped physically anymore, they're just uploaded to the theater's system and set to be playable when the premiere date rolls around."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bj8cpf | When jump starting a car, why do instructions say attach the jumped cars negative cable to the frame? | Because that has never worked for me, in any car I've ever jumped. Every instruction I read, it says attach the negative jumper cable for the car being jumped to unpainted metal on the frame. Every time I've done that, in every car I've ever jumped, nothing happens. It's as if nothing is connected at all. When I attach the negative cable to the negative terminal of the battery being jumped, it works. When negative is connected to negative, the car being jumped indicates it's receiving some power. It bugs me that the common instructions for this procedure have never ever worked for me, and that what has worked is something folks say to specifically not do. Clearly I'm doing something wrong, but don't know what. | Technology | explainlikeimfive | {
"a_id": [
"em63f7l",
"em6bvfy"
],
"text": [
"It's mostly for liability purposes. By jumping directly to the positive and negative terminals, you increase the risk of igniting potentially flammable gasses coming from the battery via the spark that often happens during the connection. These gasses can occur in certain scenarios, though is much more rare in this day and age. If they tell you to connect both the positive and negative, and you cause an explosion, they could potentially be held liable. If you find a CLEAN ground, you *can* successfully jump a car in the manner described, and it IS safer. But it is often hard to find a clean ground inside an engine chassis on a vehicle that needs a jump.",
"A good way to think about that is that same battery will be in the hands of lets say millions of consumers with millions of variant automotive background and knowledge in general. Thats millions of variables as to what might happen, not to mention the type of car, the condition, condition of the battery, etc.... Imagine a car, engine bay looks like absolute shot, things are wired waayyy not close to safe, the battery has tons of oxidation, its been used in a teactor, then a makeshift electric storage thingy connecyed to other batteries, then back in a car, the cable used to jump said car are stripped and fucked up, there might be fuel and oil everywhere, even on a rag near by. So they have to recommend the safest thing to do for the most obscene conditions you can think of because with those odds, thats probably happened more than once."
],
"score": [
30,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bj9ptx | How does code writing work? | Are they written on a special program? Where is the program? How was this special program written in the first place? Thank you. | Technology | explainlikeimfive | {
"a_id": [
"em6fzku",
"em6j68t",
"em6gunk",
"em6g1hu"
],
"text": [
"You can write code for high level languages in a text editor like notepad. There are editors that have extra functions for code writing to make it a little easier. At the top end for ease of use are Integrated Development Environments (IDE) that combine text editors, code assembly where necessary, program running, monitoring and error detection functions. Depending on your expertise, Machine Code and Assembly language programs can be written in simple editors allowing hexadecimal codes or assembly mnemonics to be entered directly.",
"Programing is like an onion, done in layers. Lets start at the very center layer (the lowest point) This would be Machine code, essentially a way for users to input 1's and 0's, or Hexadecimal code that the computer will run. Up a layer you get the Assembler, Compiler or Interpreter. These all serve a similar purpose of converting what code is written, into machine code for the computer to run. One more layer up you get the Language itself. think of this like different languages a human speaks. There are many, and they all have different ways of doing things. Depending on the language you choose, what you write can be very different. So, how do we get to the point of being able to write code as we do? start at the center as i did. We write machine code to make a compiler, interpreter or assembler. From there we can write code in our chosen language and use the machine code program we wrote to convert that much more complex code into binary. Now this is where things can get confusing. the programs we use to create new programs can/will be based off previous programs. So lets say you make a compiler for your language, someone else can use that language to make their own compiler. this eliminates the need to write the bare machine code in binary. This leads to what would look like a tree of different languages all with their own branches, all leading down the Trunk of the tree (Machine code) This is oversimplified, and not a complete breakdown, but i believe it should give you a basic understanding of how it works. Hope this helped!",
"So you write a program on a program. But how was this original program written? Thanks for the info, but remember I'm 5 :))",
"It involves a language that the computer understands. You’re basically a linguist. Think of a computer like being a dog you want to do tricks but instead of it understanding the English you know it only understands let’s say Danish. Programs are written in a language someone else made up that can be learned by you and understood by a computer once it goes through a break down into the simplest form."
],
"score": [
9,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bjd5e7 | When countries such as Venezuela and Sri Lanka block internet access, how exactly is that done for certain apps/websites? Think FB, twitter, whatsapp, or certain news outlets. How do they dial down so precisely leaving the rest of the internet available? | Technology | explainlikeimfive | {
"a_id": [
"em79jih",
"em7b59i"
],
"text": [
"The ISPs of the said country will block all connections to the servers of the app/website that the government wants blocked. Everything else works as normal",
"If you want to connect to say facebook, a DNS server looks up its IP number (think phone number) of Facebook, your computer sends the message to your ISP (service provider e.g. comcast) along with Facebooks IP number. For the government to block facebook it just has to tell the ISP dont send any messages to that number. The ISP has software that makes this easy."
],
"score": [
13,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bjkf6x | why audio equipment starts their levels in the negatives. | I remember when I was a child my stepdad and grandpa had high quality surround audio systems in their homes. The audio displays would always start in the negatives and peak out around 0 or +5. It took me a while to get use to this and would often turn the volume to +5 thinking I wouldnt be able to hear it, before turning on the tv. The dB are decibels correct? Does it stand for something else? | Technology | explainlikeimfive | {
"a_id": [
"em8udfe",
"em9gz6t"
],
"text": [
"dB is decibels, in this case negative means the sound was reduced by a certain amount. In your example, 0 would mean \"Play at whatever volume the source is\", -5 would mean \"Play 5 times quieter than the source\" and +5 would mean \"Play 5 times louder than the source\". It's not an exact measurement of the loudness of a sound but rather it's relative to the loudness of the source (with 0 being equal to the source, negative being more quiet, positive being more loud).",
"The most fundamental part of audio electronics is the \"amplifier\". I don't mean the amplifier that sits on the table with all the wires in the back and big knob in front. I mean the amplifier circuit inside that box. Audio, when in a box, is really just voltage, and we can modify the audio by changing the voltage. To change the volume, for example, we increase or decrease the voltage. Amplifiers are constructed in many ways: vacuum tubes, transistors, solid-state (ignore digital for now). They all work the same way: they amplify (increase) a signal (voltage). How much they amplify is called \"gain\", and in most amplifier circuits, gain is a fixed value. The signal fed into the amplifier comes out a louder/higher level, but gained-up by a fixed amount. To vary the level/volume, it turns out it was much easier to adjust the voltage of the signal going into the amplifier by simply \"attenuating\", or reducing it's voltage, than it was to construct a variable-gain amplifier. Simple resistors can build us an attenuation circuit, and a variable resistor will give us precise control over how much we attenuate. This is the big knob (or fader). If we attenuate the input signal all the way down, the amp has no signal left to amplify, but it's still amplifying (the inherent noise) at that fixed gain. This is the tiny hiss you hear even with the volume all the way down. So, almost all volume controls attenuate a signal, from negative infinity all the way up to zero. Why is zero the top? Because we're not amplifying with our attenuator, we only reduce. Zero dB, in the context of an attenuator, means zero change (remember, the attenuator circuit is before the amplifier circuit) and the actual increase in level/voltage/volume comes from the amplifier circuit, which has a fixed gain. Why do meters show the same thing? They usually meter the input of an amplifier circuit, so they show the signal level minus our attenuation. Incidentally, zero dB is where the whole analog audio system wants to operate. That's its happy place. If your meters average around zero and maybe peak at +3 or even +6 you're doing ok. Why do bad streamers and camgirls sound bad? They're pushing their microphones far far past zero dB on the meters, well into the red zone, and it distorts. Zero dB, or any other value on the knob/meter, doesn't actually correlate to a certain sound volume in a room, or even a certain voltage (without getting more technical). It's all about \"change\"... how much did you change the signal by moving the fader. Zero dB on the fader in my studio is a nice strong volume to listen to, but zero dB on my system by the TV will rip your ears off. So let's say I have an amplifier circuit with a fixed gain of 80 dB and I build a fader before it. If I set the fader to zero, my output is +80 dB. Set the fader to -10 and I get a gain of +70. Fader at -30 is a gain of +50 and so on. Fader at minus infinity means none of my input signal passes thru the attenuator to the amplifier. I, as an operator, typically don't ever care what my output gain actually is, what I care about is how many dB's I am changing my signal by, and I can watch the effects on the meters. There's more to it of course, like when talking about microphone connections, or why a fader/knob/meter will max out at +5 or +10, or digital audio, or VU's, or dB SPL.... but this is the eli5 gist of it."
],
"score": [
11,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bjlya5 | How do apartment building fire alarms work? | For example, if I set off the smoke detector in my apartment, will it set off the whole building? Is this system able to tell the difference between burnt food and a legitimate structure fire? | Technology | explainlikeimfive | {
"a_id": [
"em9i03c",
"em97re4"
],
"text": [
"This depends on jurisdiction, when your building and alarm system was built, and possibly the whims of the local inspector. You got options: 1) You have \"single-station\" smoke detectors in your apartment and \"system\" detection, if at all, in the rest of the building (hallways, common areas). Your burnt toast shouldn't alarm the whole building. 2) The master panel monitors your single-station smokes or you have system smokes in your apartment. Depending on panel programming, your burnt toast may only alarm your unit, or the whole building if a neighbor also burns her toast at the same time. The 2nd detection may also happen if you open the door to vent smoke into the hallway (if there's a detector out there). It's really dumb to program the panel so that detection in a single apartment alarms the whole building. Fire departments hate false alarms and the newer codes have been making many changes to reduce false alarms just like this. I've been a fire panel tech 15 years, in 3 cities in 2 states. It's highly likely that burning your toast will only result in an upset roommate, and not fire trucks.",
"yes, most fire codes require that fire alarms be linked together. the smoke detector detects smoke. and it doesn't differentiate it from actual fire or burnt food. they work by running a current from one end to another and smoke blocks that flow of current and sets off the alarm. fire extinguishers work differently, they usually have a small capsule that b locks the water flow. if that capsule overheats and bursts ie from a fire, then the sprinkers starts flowing."
],
"score": [
10,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bjwwxk | Why would storing my previous passwords be more secure than letting me use whatever password I want indefinitely? | Technology | explainlikeimfive | {
"a_id": [
"emby8l7",
"emcvtqg",
"embvnun",
"emcvl0t",
"emcwrpd",
"emch12v",
"emdplkr",
"emd141a",
"embvjzj"
],
"text": [
"As others have said, passwords are normally hashed. Password change requirements are typically only used in enterprise environments, in which a user may write down their password or share it with another employee. It's not necessary for the normal user, in fact, it's generally considered less secure to make passwords expire, as most users just make small changes the password. IE: *Password1, Password2, Password3*, etc.",
"It isn't. It's an outdated practice that is [no longer recommended]( URL_0 ). The passwords should be stored as password hashes, however cracking the password history is often tremendously useful to an attacker as it provides insight in to how you compose passwords. Also, a lot of users modify their passwords in a predictable way each reset, so if I know you start at Password1, then progress through Password2, Password3, Password4, and Password5, I can guess that your next password will be Password6, which helps me maintain access as an attacker.",
"It's about protecting you and their company from someone using an old password. Most hackers that get names and passwords don't go logging in right away, and will sit on them for awhile. By forcing you to change your password every so often, it puts an expiration date on how long the bad actors have access to your account. If you keep re-using the same passwords, it defeats the whole purpose.",
"Another EILI5 question: why not just create a 5 second delay on password attempts? Wouldn’t this completely eliminate every kind of brute force attack easily while being almost imperceptible to a human user?",
"This is actually not recommended anymore. They now recommend a 16+ character passwords with no expiration. Plenty of people already mentioned hashing so I'll leave that out here.",
"They shouldn't be storing your previous passwords (or your current one). What they store is a hash of your password. Basically it's a one-way scramble. You put in your password: `hunter2` and you get out a big string like this: `F52FBD32B2B3B86FF88EF6C490628285F482AF15DDCB29541F94BCF526A3F6C7` There's no way (at least that we know of) to do that operation in reverse. That means that even if the server is hacked and that string is leaked, there's no way for the hacker to get your password from it. When you log in, they take the password you gave them, hash it, and check to see if it matches the hash of your password.",
"UnethicalLifeProTipe: a trick to get around this is after you change your password, change it 4 more times manually, then change it back to the one you like. I do it all the time.",
"it's not. but it trades off a trivial amount of security in order to significantly raise the security *floor*. minimum length restrictions, character requirements, password blacklists, and repetition blockers all reduce security by reducing the search-space. put another way, if you accept *anything* as a password then an attacker has to try *everything* in order to brute force one. however, if you put some restrictions on the acceptable passwords then an attacker now doesn't have to try anything that doesn't meet your restrictions, shaving a lot of possibilities off and therefore making it easier to attack. however, password strength requirements, when not overbearing, can still be a very good idea, because the types of passwords being excluded are so trivial that it wouldn't take long for an attacker to run through all of them anyway, and what you gain with that trade-off is that your users can't use absolute bottom of the barrel trash passwords, which increases overall security of your platform at a negligibly trivial cost to any particular user's password strength.",
"They aren't storing your password as u/popisms explains pretty well, even if they were, most of the time your password doesn't get stolen and then used right away. Typically it gets stolen, then sold, then used later on. If you were to change your password in that time, it becomes useless."
],
"score": [
396,
203,
118,
32,
17,
13,
8,
6,
5
],
"text_urls": [
[],
[
"https://pages.nist.gov/800-63-FAQ/#q-b5"
],
[],
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bjx1gq | Why are most commercial solar panels only 25 % efficient? | Technology | explainlikeimfive | {
"a_id": [
"embwbae",
"emcnbqr"
],
"text": [
"Photovoltaic solar panels *in general* have an efficiency limit of about 33%, enforced by physics and how electricity behaves, and is known as the Shockley-Queisser Limit. There have been efforts to go beyond that limit using things like lenses and mirrors to focus sunlight, but even then the world record of efficiency is only around 46% or so. After that point, modern commercial cells are capped at around 25% because that's the point at which increasing the efficiency starts to get particularly hard, and thus particularly expensive. More importantly, thermodynamics puts a hard limit on most of these kinds of energy processes, and the limit is essentially just a function of the difference in potential between the high-energy state and the low-energy state in a reaction. The simpler way to see this is in heat engines, and the efficiency is capped by the difference in temperature between the ambient (low-energy) and the inside of the engine cylinder where combustion happens (high-energy). With solar cells trying to focus in on an area of the sky around the size of our sun, the *absolute* limit for solar cells is around 69%.",
"So r3dl3g gave a pretty good scientific explanation. An eli5 of why it isn't close to 100% is that if you consider that panel sitting out in the sun. It will get hot. That heat is lost energy. You can also see your reflection in it, which is a result of light bouncing off. Also lost energy. There are many more such inefficiencies explaining why it will never get close to 100%."
],
"score": [
61,
13
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bjy7ka | Why do 3D environments render almost instantaneously in games but take multiple hours or days to render while making 3D animated videos? | Technology | explainlikeimfive | {
"a_id": [
"emc6xfh",
"emctzcy"
],
"text": [
"Long story short. 3D Animated movies are on a totally different scale of detail. 3D games are optimized for performance, 3D animated movies/shows are optimized for detail. & #x200B; Texture resolutions are much higher (And I don't think they compress them), animations have many more joints to deal with, physics are totally different, lighting is much higher quality... Pretty much everything is better in 3D animated movies/shows.",
"Because they use different drawing strategies. Games essentially fake how light works in a 3d scene. It will approximate how light interacts with various objects with really simple math. We've had years of basically tweaking the same strategy to make it look more and more realistic, but this method will never result in something trulyrealistic. Animated videos on the other hand have time to spare so they don't need to fake how light works in a scene. They have all the time in the world (more or less) to actually simulate the physics of how light works. As a result, how light works with a scene (reflections, shadows, etc) are a lot more realistic because we can actually simulate the way light works. Put another way, you throw a ball in the air and try to guess where it lands. 3D games go, the ball will probably land somewhere around that park bench. And that's good enough for games, you gotta draw it fast so people won't notice if you're off a little. For animations, you got plenty of time so you go, i threw this ball going 1 m/s at a 30 degree angle, it will land exactly on the corner of the bench. Note that the ultimate goal of 3D games is to look as realistically as possible. NVidia's newest round of graphics cards can do some of this realistic simulation of light. The results are truly amazing, but we're still a ways off from it becoming more common. URL_0 Pay attention to the reflections, especially in the water and on the underside of the bridge. You can fake that effect in a game but only with ray tracing can you simulate it without requiring an artist to actually draw it."
],
"score": [
8,
3
],
"text_urls": [
[],
[
"https://www.youtube.com/watch?v=gGbWZjPXBYM"
]
]
} | [
"url"
] | [
"url"
] |
|
bjycui | What’s the point of logarithmic dimming curve? | Technology | explainlikeimfive | {
"a_id": [
"emc8kuq"
],
"text": [
"A logarithmic dimming curve results in the perceived light level changing linearly You don't see 500 lumens as half as bright as 1000 lumens, you see it being 70% as bright, and 250 lumens as half as bright If you use a linear dimming curve and a rotary dimmer then half your perceived dimming range is in the highest 75% of the knobs movement, and the other half(the part you care about) is squeezed into just 25% with quarter brightness being just 6% through the knob's rotation A logarithmic dimming curve makes it so the knob being set to the middle looks half as bright as max, and 25% looks roughly a quarter as bright. It makes the dimmer behave how you expect it should (half is half, quarter is quarter). Unfortunately this all goes to hell with LED bulbs"
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bk17rn | Why dont you get zapped with electrecity when putting your body between a wireless charger and whatever its charging? | Technology | explainlikeimfive | {
"a_id": [
"emd06go"
],
"text": [
"The charger work by magnetic induction. You have a magnetic field that changes direction thousands of time per second. It is a transformer with a air core where you have one coil in the charger and the other in the device you charge, So because humans are not magnetic and you can't induce a electrical current by a changing magnetically field. If it did not contain a system to detect if there is some other conductive object on it that is not the correct type of receiver you would be able to hear up metallic objects on it. A wireless charger is a lot like a induction stove top where you heat up pans with a alternating magnetic field but it do not heat up humans or the glass on the stove. The power level on a induction stove top is many times higher then a wireless charger."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bk4ly9 | how does my weather app know how bad my allergies will be, especially for different allergens? | Technology | explainlikeimfive | {
"a_id": [
"emdv0eu"
],
"text": [
"Based on your area, and season, it’s possible to predict which types of pollen will be the most abundant. Also if it hasn’t rained in a while, the counts will be high but after/during rain it will drop down some. They also measure which types of pollen are also the most abundant."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bk73tr | Americans talk about 'cable'. In the UK we have either broadcast transmission over aerial, or satellite. How is 'cable' TV different? | Technology | explainlikeimfive | {
"a_id": [
"emedwrl",
"emefhfy"
],
"text": [
"Cable TV comes through cables that lie under the roads and pavements and into your house. The UK does have cable TV, that's what Virgin Media is. It's only available in places where they have cables installed, but that covers quite a lot of the population.",
"In some cases the world \"cable\" has become synonymous with any method of receiveing paid programming broadcast. Like hoovering is synonymous with using a vacuum cleaner. Hoover is a brand name. Like Kleenex or Xerox. When paid television was first introduced to the US it came into the house via a coaxial cable. Similar to a telephone line. In most cases it was installed right alongside existing telephone wiring. Later came large, expensive satellite dishes, but not many people had them. People stayed with cable for a long time. There was no other option. The internet was over slow telephone connections at this time. High speed internet was only over expensive dedicated lines. It wasn't until the small satellite dish became available that there was an alternative."
],
"score": [
18,
8
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bk8ii3 | if someone ask me to explain what is Internet an how it works, in the easiest way possible, what would I tell them? | Technology | explainlikeimfive | {
"a_id": [
"emeq7lv",
"emex9gj"
],
"text": [
"Think of it as a giant library with infinite space, stored in virtual reality, that anyone can write for/add to. No one really owns the library, but there are several dedicated sponsors that keep it up and running, and anyone can add anything to the library that they want, when they want, as long as they have access to it. Browsing it is the same, essentially, except web browsers (chrome/internet explorer, etc) are kind of like the librarians and you give them the things you're searching for (website urls), and they find them for you immediately. Some librarians are specially dedicated to finding things (search engines like google and yahoo), and have infinite connections. They send you to all the right sources you need, rather than sending you to a direct result themselves.",
"It's basically just computers making \"phone calls\" to each other for information. I call up Amazon's computers for information on its products and then I tell them I want to order something. Our Internet Service Providers are like the \"operators\" of the internet, taking our request to make a call to someone and forwarding it to another operator who is closer. We might go through several operators until we reach our destination, but the process is so seamless that we never really need to know or care what steps are being made along the way. In the end, we're \"directly\" talking with the desired computer."
],
"score": [
8,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bk8jvr | How is storage freed in computer hardware at a physical level? | I understand that you can delete software files easily, but what is the physical process of deleting that data? | Technology | explainlikeimfive | {
"a_id": [
"emer7e7",
"emeqiou"
],
"text": [
"When you delete, it just marks those memory cells as rewritable. It’s not truly deleted until something is saved into it.",
"There's an area of data on the drive called the file allocation table which keeps track of which areas are in use. At the basic basic level removing an entry from here is a \"soft delete\" because that allows it to get physically overridden on the drive media when some new data is saved. (Saving data involves looking up spare areas using the file allocation table then physically manipulating that part of the drive to store information.). A hard delete is to go one step further and actually write 0s (or random data) to the area on the drive, obliterating trace of what was there before."
],
"score": [
9,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bk9ul1 | Are dárk themes in apps/websites better for your eyes and if so, how? | Technology | explainlikeimfive | {
"a_id": [
"emf321x",
"emflzpr",
"emf77yk",
"emfq9qi"
],
"text": [
"Ah interesting. I came across an article, which changed my mind. The opposite is true: Brighter is better for the eyes. Bright themes causes your iris to narrow and like a camera lens aperture, actually makes things sharper and easier to focus. Dark themes on the other hand causes your iris to widen and this is comparable to bokeh effect in images, which is blurry. The effect on sleep could be a different story though. Instead, blue light reduction is touted to be helpful in this regard. Ihmo dark themes in phones are meant to save battery and not your eyes x_x",
"Dark themes are better in otherwise dark rooms, bright themes are better in otherwise bright rooms. Staring into a bright light with everything else around being dark is bad and staring into a black hole with everything else around being bright also is bad. The average brightness of your screen should ideally be as bright as the wall behind or the room around it.",
"Not better for your eyes maybe, but light (especially blue) has been proven to make you sleep worse.",
"I use dark themes everywhere I can, because they reduce overall amount of white color I see. Think of a browser - it’s white literally everywhere, or at least on the sides of the page. My eyes are pretty sensitive, and my monitor brightness is usually like 10, so dark themes helping a lot, especially in the evening..."
],
"score": [
50,
14,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bk9wfh | When unsubscribing from list-serv emails (emails from companies about sales, new items, ect.) why does it take anywhere from 3-10 days to actually be removed from the list? Why can’t it be an instant process? Is it a marketing scheme or is there a tech reason? | I’ve slowly been trying to remove all these marketing/spam email lists from my life, but almost every time I unsubscribe I am met with a message that says something like “it make take up to X days for this change to be reflected”. Why is that? | Technology | explainlikeimfive | {
"a_id": [
"emf205f"
],
"text": [
"Purge processes tend to be run on a schedule. It depends on how often they've scheduled that process to run. There's also data caching that has to be updated and that's on a schedule as well."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bkau81 | How do series like Planet Earth capture footage of things like the inside of ant hills, or sharks feeding off of a dead whale? | Partially I’m wondering the physical aspect of how they fit in these places or get close enough to dangerous situations to film them; and partially I’m wondering how they seem to be in the right place at the right time to catch things like a dead whale sinking down into the ocean? What are the odds they’d be there to capture that and how much time do they spend waiting for these types of things? | Technology | explainlikeimfive | {
"a_id": [
"emfb3d9",
"emfj5lf",
"emfjgwf",
"emflrwx",
"emforsl",
"emfta35",
"emfbd9q",
"emfke49",
"emff53k",
"emftlfi",
"emftygv",
"emfyejj",
"emfqwsx",
"emfv1it",
"emg3eo9",
"emfqnt4",
"emfv2bq",
"emfxyb6",
"emg5es5",
"emg74xt",
"emfxoe5",
"emfrpsg",
"emftthy",
"emh6re8",
"emfxv7z"
],
"text": [
"some of the series at the end do a brief section about how they go about capturing the footage that they showed. They make their own custom rigs with various types of cameras to help them get shots. They leave camera 'traps' in places and hope to get lucky with them. They wander around following research or local guides to help increase their chances of being in the right place at the right time. So a lot of it is somewhat down to luck. They will know from research roughly where to go for certain things, but being able to capture specific things is down to luck on whether they get any usable footage in the days they allocated at a site. Depending on what they are looking to film at any given site, the time they allocate will differ.",
"Videos like these they compiled from thousands of hour of footage over a long time. Planet Earth took 5 years to make. A camera person could be set up in a location recording several days worth of footage of nothing but trees before finally getting the 10 second clip of a moose walking by. Then they'll typically follow the animal several days. Theres not much of a difference in skill/dedication between a scout sniper and a wildlife photographer, other than one shoots with a gun the other shoots with a camera.",
"The snow leopard scene in Planet Earth was THREE years of trying to film it. After only getting about an hours worth of filming the animal asleep, and just as they decided to give up, they captured the hunt scene that made in the show.",
"Can someone answer OPs question about they film inside ant hills?? Thats question ive wondered forever just never asked",
"I always think of [this]( URL_0 ) video. In regards to the part of your question about how they film the sharks eating the whale carcass; they drug the carcass out to sea after it washed up on a beach and a photographer actually climbed on top of it and filmed while the sharks feasted on it.",
"The recent Attenborough series has a bonus episode where they take you behind the scenes of some of the shots. I believe it was called \"our planet\". It may help answer some of your questions, for example it took 2 people living in a shed for the winter 3 years to capture just 25 secs of footage of this super rare tiger.",
"The odds of finding something interesting to film are good if you're filming with multiple crews over span of years. And as with any film, the sequence the audience sees the scenes are not necessarily the sequence that the actors (animals) actually performed. Since people are bad at distinguishing animals traits, the actors themselves don't even have to be the same from scene to scene.",
"A lot of the shots are also shot with specific lenses on extremely expensive cameras, they might be 500 feet away from something and just zoom in to make it seem like it's right in front of them, they even attach them to drones to get the magic shots",
"Some of the dead whale scenes they were able to capture because they followed a whale that beached itself, died, and was dragged to open water so it didn't rot on the beach.",
"There is a podcast about wildlife called \"The Wild\" [ URL_0 ]( URL_0 ) and the most recent one was about a videographer who was trying to film siberian tigers in the wild for the first time ever. 7 months in a hole in the ground, eating peanuts, rice, vitamins, salt and water. Twice per week exiting the hole to take a #2... in a bag that is sealed and hauled out later. Oh and it is -30C. He is literally in a hole in the ground for months! The photographers are hard core to get that footage!!! Have a listen. That guy is both cool as hell and a bit insane. He and his resupply guy wouldn't make eye contact so that it wouldn't remind him how lonely it was out there alone.",
"It takes a lot of luck and patience. It can take years to capture one scene. In Blue Planet II, the film crew traveled to French Polynesia to film groupers spawning. That event happens for less than an hour every year. They completely missed the spawning the first year, despite all the planning and preparation they did. They had to leave and come back the next year to film it. It takes hundreds, if not thousands, of hours of filming to successfully capture an event: \"The team then clocked up several thousand hours diving with the grouper, including round the clock sessions the following year when they were due to spawn, to film the event.\" URL_0",
"The recent series \"our planet\" had an extra hour long episode in which they explained how they got footage of a very rare tiger. Members of the team had to take turns living in a small hut near where they had found evidence of tigers being in that area (paw prints, poo etc) They stayed in that hut all by themselves for a week or more, not leaving at all and waited for the Tigers to pass by. The most amazing shots though were captured with trap cams. Any movement would turn on the camera and start filming. When they were filming Orangutan, they had to treck through the forest following them. 1 team member carried the huge camera, another carried the huge tripod, then when they stopped they had to assemble it all and try and film the orangutans before they moved again. Which they did, alot. Eventually after much perseverance they managed to film the amazing moment an orangutan broke open a dead tree containing an ants nest and then used a stick to poke inside to get to the ants.",
"That dead whale was towed to that particular spot and left there for the express purpose of filming it. Much of what you see in nature documentaries is faked or manipulated to some degree. Apparently 'wild' animals are often semi-tame and filmed in large enclosures. I've been involved in the production of enough TV and documentary films to see and hear about many of the tricks. For a great expose of this, read Chris Palmer's book, 'Shooting in the Wild.' Chris, whom I got to know a few years back while he was teaching film at American University, was a producer on Blue Planet and can tell you about all sorts of tricks and sneakery used.",
"Underground stuff (ant hills, dens, etc ...) are artificially made with a glass barrier. It can be constructed in a way to get the best possible shots.",
"Many shots are completely fabricated on sets with recreated environments and creatures raised in captivity, or transplanted from the wild. This is especially true with the scenes with things like ants.",
"Not an answer but [you might find this docu series by Vox]( URL_0 ) interesting! They're a few YouTube mini episodes on how they film that stuff!",
"A lot of the insect footage is filmed on “sets” indoors. Set up a terrarium, drop in the bugs, and there you go. It’s a bit more difficult to get correct lighting for small scale stuff.",
"I'm currently at the end of ''Our Planet'' (Netflix) and there is a behind the scenes episode as the last episode. I'll try to pick up interesting details from it for you. They said they had to watch 400 000 hours of just camera trap footage. Their crew is 600 in size. To capture some footage of a siberian tiger they spread out around its territory and lived in small boxes (like 2x2x3 m)(they roteted turns weekly) and waited for it to appear. Of course they had cameras with them and camera traps that had to be regularly checked. For some shark footage they have scuba gear with chainmail on it to stop their bites. also they have one guy lighting the place and another filming it (and third guy filming both of them). A lot of the few second shots took weeks to film when they were in a jungle. (Also they put some cut content in there where walrus jumps from 80 meter high mountain to the ground and even the film crew was like WTF?)",
"I want to see the setup that caught all of the \"iguana running through the snake pit\" scene",
"Not an ELI5 answer but you might be interested in reading this [ama]( URL_0 ). By a guy that lived in Antarctica filming emperor penguins for 11 months for a BBC show.",
"The BBC has a documentary called Life In The Undergrowth that shows the life of insects if we were viewing it at their level. I think they show how it’s done. A must see",
"Custom rigs, years of filming for a few hours of footage and the fact that the BBC has been doing this for decades",
"They also use high end expensive cameras with long battery lives so they can leave them in the field for weeks at a time",
"An incredible amount of time and effort goes into programmes like Planet Earth. Research will begin over a year before filming dates are even considered. Researchers and producers on the film team will reach out and find leading scientific researchers who have likely been observing and researching a specific species and/or behaviour for years. The researchers they find can then suggest the best places and times to film the species and behaviour they want to see. The crew then spend months or even years on location filming long hours, every single day. Often when you see a sequence on a wildlife TV show (let's say a cheetah chasing a gazelle), it's not just one chase. It will be shots of multiple chases that took place over days, weeks or months and may not even be the same cheetah. There are exceptions to this, but usually, it's just physically impossible to film a sequence like that from multiple angles in the ways that produce the compelling sequences we are used to seeing on these shows. This is becoming less common as time goes on though, as technology is making it more and more possible to cover natural events more completely. The odds of capturing the events that they do are fairly high as they film for so long, in the best places in the world at the best times as recommended by the worlds leading experts on the species. Some of it does just come down to luck, but honestly, it's a hell of a lot of hard work from a lot of people. As for the technical how, there's a lot of technological innovation that the wildlife film-making industry produces trying to work out new and interesting ways to film in unusual environments. There are camera gimbals costing half a million, based on missile technology that are so accurate that you can have the camera mounted on a vehicle travelling 60mph over rough ground hundreds of feet away from an animal running full speed the other direction and tracks it perfectly in shot, filling the frame, completely vibration free. There are lens modifications that allow cameras to film macro scenes (very small, like ant sequences) without looking like they are just zoomed in on, and very realistic animations with cameras in the eyes for getting closer to wildlife without disturbing them. Source: I'm a documentary camera and drone operator who has worked on shows for the BBC, BBC NHU, Discovery, PBS, NatGeo, C4, etc. **Tl;Dr:** Lots of hard work, for a long time, cooperating with world leading experts in the species they are filming, using groundbreaking innovative camera technology specifically designed for their unique purposes.",
"> As a general rule, it takes about a week to film one minute of wildlife footage. The producer and crew dedicate a significant chunk of that time to letting animals grow accustomed to the presence of a camera: they might erect a camera in the animal's territory and leave it there for several days. Or they might turn on a drone, but not fly it, letting animals get used to the whirring of the propellors. Generally speaking, once the animal decides the camera is neither predator nor prey, they leave it alone. URL_0"
],
"score": [
6055,
1390,
1306,
363,
311,
93,
70,
57,
55,
41,
28,
18,
12,
11,
10,
7,
7,
7,
6,
6,
5,
4,
4,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[
"https://www.youtube.com/watch?v=T20vkGZxULo"
],
[],
[],
[],
[],
[
"https://www.kuow.org/podcasts/thewild"
],
[
"https://www.google.com/amp/s/www.mirror.co.uk/tv/tv-news/blue-planet-film-crew-were-11483428.amp"
],
[],
[],
[],
[],
[
"https://www.youtube.com/watch?v=qAOKOJhzYXk"
],
[],
[],
[],
[
"https://www.reddit.com/r/IAmA/comments/aqityx/i_am_lindsay_mccrae_a_cameraman_who_spent_11/?utm_source=share&utm_medium=ios_app"
],
[],
[],
[],
[],
[
"https://www.wired.com/2017/03/crazy-new-camera-tech-made-planet-earth-2-possible/"
]
]
} | [
"url"
] | [
"url"
] |
bkdu0a | how does hydroponics work if overwatering plants kills them? | ELI5 I just don't understand how constantly being in water doesn't kill plants if overwatering does. Can only certain plants survive in hydroponic systems? | Technology | explainlikeimfive | {
"a_id": [
"emg2uti"
],
"text": [
"It's all about the oxygen. In wet soil, the roots become oxygen starved and rotten. Same thing happens in stagnant water. Hydroponic systems use air blowers to fill the intake water with bubbles and oxygenate it. If you stop the blowers, then the root zone gets stagnant and rotten just like in over watered soil."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bkfjr0 | Why aren't small diesel engines more popular in the USA like they are in Europe? | Technology | explainlikeimfive | {
"a_id": [
"emgb4kq",
"emgbc41",
"emge3hs"
],
"text": [
"There hasn't been a strong economic motivation for the cost of transitioning to diesel architecture in the United States. Even when gasoline is expensive, it tends to cost around half as much as in typical European markets (due in part to taxes, in part to supply logistics) - which was especially true in the 1990s when diesel's popularity especially took off in Europe. While consumers might still appreciate a marginal advantage in any given market, the producers of vehicles need a lot of incentive to change how their cars are powered. That has not been present in the US, and lately has been leapfrogged by the move to EV.",
"Traditionally diesel engines have had lower power, higher noise, were more expensive, smelled bad, and had difficulty matching the more strict US emissions standards. And then they cheated on them.",
"Diesel engines cost more to build. Diesels put out way worse emissions than gas engines regarding particulate matter and the soot burning DEF system adds even more expense to the vehicle. Also here in the US people like to buy newer cars for the most part so the longevity of diesels isn't as coveted."
],
"score": [
10,
4,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bkfvqg | How is code, compiled down to machine code (1s and 0s) changed to voltage? | Technology | explainlikeimfive | {
"a_id": [
"emggloj"
],
"text": [
"Well it's not really ELI5, but it boils down to the transistor, which is an electronic switch. A transistor has an input, a control, and an output. As used in digital circuits, these are binary, having only two states, on or off. So, you can wire up this switch in a few ways. One is where if the control is 1, the output is the same as the input. If the control is 0, the output does nothing. This is called a buffer. The other is the opposite, where if the control is 0, the output is the same as the input. If the control is 1, the output does nothing. This is called an inverter. Usually we tie the output to 0 through a weak resistor so that if the output is doing nothing, it defaults to 0. From these two types of transistors, we can build a general purpose computer by combining them in ways to create logic circuits. But you need a lot of them. At the next layer up, we create devices called gates. The first is the AND gate. You put two buffer transistors A and B in *series,* where the output of A is tied to the input of the B. Also tie the output of B to a weak resistor to 0, or logic 0 and tie the input A to 5V, or logic 1. Now the only way to get 5V on the final output of B is if it passes through both buffer transistors, meaning that both controls of A and B are on, or at 5V or, digitally, at 1. We say that the output is 1 if both control A and control B are 1. If either is off, then the weak resistor pulls the output to 0. Let's set that AND gate aside and make an OR gate. This time A and B are wired in *parallel* where both of their inputs are 1 and are tied together, and both of their outputs are tied weakly to 0. Now, if either control A OR B is on, they will provide a 1 to the output. Otherwise, the resistor pulls the output to 0. What can we do with that? Well we can do some interesting things when we tie gates together. If there are no loops, it is called a combinational circuit where the outputs rely only on the inputs. Suppose you wanted an output to become 1 only if the input bits are 6, or 110 in binary. You connect the first 2 bits (11) to an AND gate, and the third bit to an inverter. Then connect the output of the AND, and the output of the inverter to another AND. In this case, the first AND is 1 only if the first 2 bits are both 1, and the inverter is 1 only if the third bit is 0. The second AND is 1 only if the first AND and inverter are both 1. So you have (1 AND 1) AND (INVERT 0) which gives you 1 only if the inputs are 110. This is called boolean Algebra, named for a guy named Boole, as it goes. By combining gates you can come up with very complex controls, for example, to add numbers, or turn on circuits by decoding the binary format of instructions. In a computer there is an Arithmetic Logic Unit (ALU) that can add, subtract, shift and otherwise manipulate data. For the instructions, you have a microcode unit that decodes instructions to route data around and control the ALU. There is one last thing, memory. For memory, you put loops in the combinational circuits and what is known as a clock signal. The loops will cause feedback in the gates inputs and the are wired with other gates to the clock so that they only react to their inputs when the clock is 1, and freeze when the clock is 0. They may also be enabled or disabled with other inputs that may be control signals or outputs of the ALU calculations. What this means is that they can store a bit until they are allowed to change it based on new input and a write control signal which is just another bit. These are called sequential circuits because changes flow through it in steps, or sequences, as the clock toggles back and forth between 0 and 1. So now you can have what are called *registers* in the processor to hold numbers to present to the ALU, and capture the results, to be stored elsewhere or rerouted back into the ALU for more computations. That's the very basics. For a good ground up hand holding, pick up Charles Petzold's book, *Code*. It will walk you from light bulbs to assemblers, and it's a short hop from there to compilers. In reality, of course it's more complex. For example, Boolean Algebra states that you can build any combinational circuit only using a gate called a NAND gate (AND with an inverter on the output), because you can build any of the other types with NAND gates. SO, you only have to use one type of gate to build your functions. Programmable logic devices (PLDs) do this."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bkqeao | I've seen clips of players im games like Minecraft and others make fully functioning calculators. How is this done/possible? | Technology | explainlikeimfive | {
"a_id": [
"emit4r8"
],
"text": [
"This is a very good intro to some very approachable CS concepts. If my explanation is confusing, skip to the end for some YouTube links Most computers are made up of assembled \"logic gates\". They take a set of inputs and produce a set of outputs, the inputs and outputs are either \"on\" or \"off\", aka 1 or 0. There's a handful of \"basic\" logic gates. It's easiest to give examples: The NOT logic gate takes an input and outputs the opposite value; if you feed it a 1 you get a 0 and if you give it a 0 you get a 1. The AND logic gate takes two inputs and produces one output. If both of the inputs are 1, the output is 1. Anything else produces a 0. The OR logic gate takes two inputs and produces one output. If either input is 1 it produces a 1, if both inputs are 0 it products gives you 0. You can plug these logic gates together to do things. With some basic knowledge of binary numbers you can very easily create a simple adder that adds two numbers together. Fun fact: you can create every single kind of logic gate out of one kind, the NAND gate (Not-AND). In these videogames there are mechanics you can use to imitate these logic gates. All I know about Minecraft is that it uses redstone to do this. I've seen similar things in little big planet though. Look up \"logic gates\" on YouTube for some intro materials. It's one of those concepts that's easy visualise in video form. Once you have that down, look up how to produce a logic gate in your game of choice. URL_0 URL_1"
],
"score": [
6
],
"text_urls": [
[
"https://youtu.be/gI-qXk7XojA",
"https://youtu.be/UvI-AMAtrvE"
]
]
} | [
"url"
] | [
"url"
] |
|
bksn66 | How did Stephen Hawking’s voice tech work? | How does voice text for anyone who’s paralyzed work? Like the basics and the more advanced parts. | Technology | explainlikeimfive | {
"a_id": [
"emj8h3v",
"emj8r32"
],
"text": [
"He had a small screen where he could select letters & words He had one functional muscle in his cheek he could use to input commands to the screen A computer reads out the message when he is finished composing it.",
"I just watched an interview with William Shatner, who had interviewed Hawking. He typed by twitching a muscle under his eye. When you see Hawking on TV interviews, he's been given questions beforehand so he can respond on camera quickly (probably why he could be so witty). Shatner said Hawking asked him a question on the spot about Star Trek and he said it was a laborious process."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bkw4ar | Does airtight automatically mean water proof? How about visa versa? | For example - were space suits made waterproof for training purposes or were they already waterproof and it just so happened to work out for underwater training? | Technology | explainlikeimfive | {
"a_id": [
"emjwlr6",
"emk1qwo",
"emkwfur"
],
"text": [
"Air molecules are smaller than water molecules so airtight is generally automatically waterproof. Think about it - if you have an airtight container (say, a bottle) and hold it underwater it stops water getting in and air getting out BUT... Airtight things are usually designed to keep air *in* while watertight things are often designed to keep water *out* so it's not as simple as that because something like a submarine is designed to hold out huge pressures of water, which is a much more difficult proposition than holding in normal atmospheric pressure of air. So airtight automatically equalling waterproof only really counts when trying to prevent air/water going the same direction and only with reasonably equal pressures.",
"Sort of. But note that waterproof is dependent on water pressure. The further in depth you go with said item the higher the water pressure and likelihood it is no longer waterproof. This is why electronics and other items generally are given an IP rating for their waterproof rating. URL_0",
"Airtight means air can't get *through*. In most cases, this also means water can't get through. However, waterproof *does not* mean water can't get *through*, it means it can *survive* water. So if you have something that is airtight, it probably won't let water in, but that doesn't mean it will survive contact with water. For example, you may have seen dishwasher or laundry detergent pods. These are airtight and water-tight to keep the moisture in the air from ruining the products inside. However, these are not waterproof, as they are designed to disintegrate in the wet environment of the dishwasher or laundry machine."
],
"score": [
78,
7,
3
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/IP_Code"
],
[]
]
} | [
"url"
] | [
"url"
] |
bkwxk4 | When sending data (bytes) over the internet, how does the çomputer/phone know that a byte has just been read, and a new one is coming (how does it recognize the start and end of a byte) | Technology | explainlikeimfive | {
"a_id": [
"emjzv2f",
"emk5d9q",
"emk1bic"
],
"text": [
"The network device doesn't actually have to separate the bytes - it just sends a stream of bits, and the receiving device can just take every 8 consecutive bits and treat them as one byte. The only problem is to determine where the first byte starts. This is done using a [syncword]( URL_0 ) - a fixed sequence of bits which denotes that the transmission has started.",
"So think first how written language works. You can distinguish words and sentences because of spaces and punctuation. For computers there are similar things. Basically the data you want to send is bunched up using a specific set of rules defined in so called protocols. Basically think about how you send a letter, the stamp goes in a specific area of the envelope as do sender and receiver addresses. Data is also formatted using rules. & #x200B; Now since you arbitrarily (or constrained by physical limitations of the medium especially related to when the protocols where originally ratified) decided how the data is organized you know where each piece is and, like punctuation, you have specific sequences of bytes that define the start or the end of specific parts. & #x200B; Basically to recap, everything works because rules where established and both parties follow them so they can understand each other.",
"I'm a little confused about what scenario you are envisioning maybe some context will help. You ask about bytes, but the overall environment you mention is the internet. Communication over the internet is done in layers where there is a high level protocol (like http) that uses a lower level protocol to send and receive information. Those protocols use even lower protocols to send and receive data. At the lowest layer, you have signals (electrons or radio waves). The usual way to represent this is the [ URL_1 ]( URL_2 ) . /u/Schnutzel mentions syncwords which is a particular way of synchronizing at the second-to-lowest layer, [ URL_3 ]( URL_0 ) ; that's the layer of bytes. The physical layer (lowest layer) receives the basic signal and converts it to 1's and 0's. The data link layer takes those 1's and 0's and looks for patterns that represent the start and end of data."
],
"score": [
39,
8,
6
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Syncword"
],
[],
[
"https://en.wikipedia.org/wiki/Data_link_layer",
"https://en.wikipedia.org/wiki/OSI\\_model",
"https://en.wikipedia.org/wiki/OSI_model",
"https://en.wikipedia.org/wiki/Data\\_link\\_layer"
]
]
} | [
"url"
] | [
"url"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.