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ce2xog
How can a single speaker, such as earphones, produce highs and lows at the same time
Technology
explainlikeimfive
{ "a_id": [ "ety71vg", "ety1wbd" ], "text": [ "[This figure should help explain it.]( URL_1 ) A shows 4 waves each with different frequencies and C shows what you get when you combine those waves together. (Ignore B and D). A combination of different sound waves creates a single wave with a unique pattern. So instead of a speaker moving in and out by same amount (wave amplitude) at a steady rate (wave frequency) it does a mixture of varying amplitude and frequency to create one sound wave that sounds like what you get when you combine lots of different sounds. Copy pasted this from last time I answered a similar question - [ URL_2 ]( URL_0 )", "A sound wave has a single pressure value at any given point in time, so a single speaker can reproduce almost any sound wave by moving in complex ways. After all, a microphone or eardrum is picking up sound the same way- one pressure level at any given instant. The pressure can change like a sine wave which is a single frequency. Or it can be complex and contain many frequencies. For instance, a [square wave contains many odd harmonics]( URL_0 ) of the fundamental frequency." ], "score": [ 5, 3 ], "text_urls": [ [ "https://www.reddit.com/r/explainlikeimfive/comments/c7lm6z/eli5_how_are_we_able_to_hear_multiple_frequencies/", "http://proaudioencyclopedia.com/wp-content/uploads/2015/07/Figure-1-5.png", "https://www.reddit.com/r/explainlikeimfive/comments/c7lm6z/eli5\\_how\\_are\\_we\\_able\\_to\\_hear\\_multiple\\_frequencies/" ], [ "https://en.wikipedia.org/wiki/Square_wave#/media/File:Spectrum_square_oscillation.jpg" ] ] }
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ce4tn9
Why do movies shot on 35mm today look more vibrant and high resolution than 30 years ago despite film technology not drastically changing in that time?
Technology
explainlikeimfive
{ "a_id": [ "etymvv3", "etze29o" ], "text": [ "The same is also true for audio, but the ability to capture video data has outpaced the ability to process that data and display it. In the case of video, 35mm film has a roughly 11880 x 7322 resolution in an ideal scenario. With film in excellent shape and proper processing, remasters can be done with excellent quality.", "Post production Even if filmed in 35mm, the movie is digitized and post processed digitally It gets color corrected and adjusted in a number of ways" ], "score": [ 11, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
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ce5jk3
Why do TV video clips from the 90s and 2000s look so low quality?
Technology
explainlikeimfive
{ "a_id": [ "etywf47" ], "text": [ "Video has progressed this far...... We went from 240p to 480p then 720 and 1080 Now we are close to commercial 2k and 4k standard video format. Just that's it's currently minimum industry standard to stay at least 720" ], "score": [ 4 ], "text_urls": [ [] ] }
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ce7bqo
Can someone explain to me how Powerline Adapters(Networking) work in terms of sending data packets over an electrical line? It confuses me that there is no data interference when the powerlines are already occupied with 110v. Thanks
thanks
Technology
explainlikeimfive
{ "a_id": [ "etzmqdp" ], "text": [ "The power lines have 110v but it is at a steady, relatively slow frequency. The data transmission is done just by wobbling the steady wall power frequency slightly, something within the normal margin of error for power delivery but also recognizable by the right hardware looking for it." ], "score": [ 5 ], "text_urls": [ [] ] }
[ "url" ]
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ceat72
How do the grooves in records actually make sound?
Technology
explainlikeimfive
{ "a_id": [ "eu10m1m" ], "text": [ "When they're recorded, a needle cuts into the wax at various depths based on the amount of vibration caused by the original sound. Then when they're played back, it works in reverse: as the needle passes through the grooves and moves up and down over the contours of the vinyl (which match the contours made by the recording in the wax) it plays sounds based on the vibration patterns. Kiiinda like when you fill up glass bottles with varying amounts of water and blow across the top of them, they make different sounds. But instead of bottles full of water you've got grooves full of vinyl at different depths." ], "score": [ 3 ], "text_urls": [ [] ] }
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cebfx2
what is the main differences between air-to-air and air-to-surface missiles?
Technology
explainlikeimfive
{ "a_id": [ "eu1823g" ], "text": [ "There are a lot of differences, and a lot of similarities based on the missiles in question. The one largely Universal difference is in Explosive Yield. Air to air missiles tend to pack less explosives, because aircraft take less force to destroy than a reinforced bunker, and the missile may have to pull hard Gs so too much weight is a bad thing. They are also ridiculously fast, pulling up to and exceeding mach 5. ATGMs tend to have higher explosive mass and specialist warheads to destroy hard ground targets like tanks, bunkers and large structures, they also do not have to pull hard Gs to get on target and so can be larger, heavier and carry more momentum. They also tend to be much slower, after all the target isn’t going anywhere." ], "score": [ 17 ], "text_urls": [ [] ] }
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cegjqc
Why does CGI in recent movies not seem as realistic/detailed as Avatar (2009) with recent developments in filmmaking and computer animation?
Technology
explainlikeimfive
{ "a_id": [ "eu2hhnc", "eu2cuph", "eu2ib7o", "eu2jk0k", "eu2kwk0" ], "text": [ "I think part of it was that almost every bit of every scene in Avatar was CG, so there wasn't as much of a chance for anything to be obviously out of place. When there's just one CG element in the scene, it can be really obvious and look really fake.", "It all boils down to how much they are willing to spend on animators and computer time. Cheap movie: cheap graphics. Expensive movie: realistic graphics.", "Have you watched Avatar recently? It doesn't look very realistic at all. I don't blame you though. I watched the matrix recently and the cgi that I thought would never be beat looked pretty bad.", "time, budget, money, time, skill level of artist, did I mention time and money? Time and money, the talent pool is getting stretched pretty thin for senior artists too with the amount of work going on right now.", "It is all art. It isn't like this stuff is automatic. It still requires tons of skilled artists spending lots of time to pull off. Not every movie is going to have the time built into the schedule or the money to pay for it." ], "score": [ 36, 26, 7, 3, 3 ], "text_urls": [ [], [], [], [], [] ] }
[ "url" ]
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ceh3qz
how do media agencies quickly find video clips in all of the media that’s been recorded over the last few decades?
Technology
explainlikeimfive
{ "a_id": [ "eu2h76g" ], "text": [ "They have metadata for all the clips in their libraries. They search the metadata and then look at the matching clips. So, they're not searching \"all the video clips\" but rather \"all the clips they have\". After that, it's all Google/YouTube." ], "score": [ 8 ], "text_urls": [ [] ] }
[ "url" ]
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cei83g
How does clicking a box actually confirm that you're not a robot?
Technology
explainlikeimfive
{ "a_id": [ "eu2pe7x" ], "text": [ "It looks at how you click it. If you instantly move the mouse to the location and click it then it can be suspicious of it being a program instead of a user with a mouse. If the movements are suspicious then it makes you go through a special type of captcha, an identification captcha (like where it has a picture of a street and asks you to select every frame with a car in it). While it would be possible to program an AI to not only click but also solve these captchas, due to the sheer potential variance in the number of potential tests it can do it would be difficult to create any form of reliable bot." ], "score": [ 10 ], "text_urls": [ [] ] }
[ "url" ]
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cemhl3
How does the https transfer the key to decrypt the data without compromising the contents of said data?
Technology
explainlikeimfive
{ "a_id": [ "eu3snt8" ], "text": [ "If data could be encrypted with a paint colour, then... If I wanted to send you encrypted data, first I would send you some random colour paint. Next, you and I would independently choose a second secret random colour paint (both different) and mix it with the first colour I just sent you. We would come up with two new colours. We then send each other our new paint colours, and mix in our own second secret random colour with each other's new colour. The result is that we both come up with the same final colour (the final colour each being a total mix of the three colours: the original, your secret colour, and my secret colour). I can now use this final colour to encrypt the data, knowing that you will have independently come up with the exact same colour. If someone else were watching us send these colours, they would get the first colour and the third pair of colours that were produced, but it would be very difficult for them to figure out what each of our secret colours were; it would be difficult for them to un-mix the third colour back to the first colour and whatever secret colour we each chose, so they would not be able to produce their own final colour. HTTPS uses mathematics that have similar properties, easy to compute one way, difficult to reverse." ], "score": [ 11 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
cenl5r
What's the difference between mechanised, motorised and computerised?
Technology
explainlikeimfive
{ "a_id": [ "eu3sk0a" ], "text": [ "If something is \"mechanized\" it utilizes a mechanical advantage. Things like levers, gears, screws, etc. Motorized means that it incorporates some sort of motor...electric, internal combustion, whatever. Typically means that it is also mechanized. Computerized things include an electronic computer system. May or may not be mechanized / motorized." ], "score": [ 4 ], "text_urls": [ [] ] }
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cesulz
How does radar blocking technology work and are there more advanced systems which can get around those hardware systems?
Technology
explainlikeimfive
{ "a_id": [ "eu4ofop" ], "text": [ "Radar relies on a signal bouncing off the target and returning to the radar dish. If you can deflect or absorb the signal instead of reflecting it, you're effectively radar invisible. Modern stealth aircraft rely on a combination of the two - angular surfaces to deflect radar pings off at odd angles and radar absorbing paint to weaken any signal that does reflect. That's why the stealth aircraft are always a dark matte finish and always odd and angular shaped. There are also radar spoofing systems that detect the radar frequency and bombard the radar station with additional signals at random intervals to confuse it. These do not conceal the presence or general direction of your activity, but they can make the radar station extremely inaccurate." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
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ceuqrz
Why is it common practice for music streaming services like Apple Music, Spotify and Pandora to have an overlapping catalogue but video streaming services like Netflix and Hulu are seemingly all done through exclusive contracts?
Technology
explainlikeimfive
{ "a_id": [ "eu51fvn" ], "text": [ "Music companies (the record companies and artists) get paid on a per use basis. Each time a song is played, they get paid. Thats how the pay works. So the goal is to get your music in as many places as people could possibly listen to it, to rack up maximum plays. From a further standpoint, there are 3 main record companies (Universal, Sony, and Warner), and after much time, they've all figured out that individually each of their catalogs don't really provide a great service, however together its an amazing service. They've tried exclusivity, it didn't work. At all. They really really tried to go it alone, and it was a complete disaster each time. (Note: Apple was actually the company that finally got them all to work together, and iTunes was born!) Now streaming TV such as netflix, does not pay on a per use basis, they pay a fixed lump sum (or on a per subscriber basis) for unlimited usage.. You licenses the content for unlimited usage at a set rate (you generally pay a certain amount per year, say like $10M/year to license a specific show for the year, (or you pay per subscriber w/ access) but you can show it as many times as you want). Netflix, and these other companies do not have to buy exclusive rights, in fact its WAY more expensive to buy exclusive rights. However, they use what exclusive content they have to differentiate themselves, i.e. The Office is only on Netflix! Always Sunny is only on Hulu! If you want those shows you have to go to the service to get it. But of course they also have tons of other content." ], "score": [ 14 ], "text_urls": [ [] ] }
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ceuvi4
How can bronze hold an edge, but brass can't?
Both are alloys that harden soft copper, and bronze's sustained edge heralded Bronze Age weapons. 1. How does the addition of tin to copper permit an edge, but zinc to copper doesn't? 2. Pure copper blades were known in the ancient past, such as Otzi the Iceman's ax. But are those much better than a brass blade might have been had brass been discovered before bronze?
Technology
explainlikeimfive
{ "a_id": [ "eu52sbc", "eu53k1k" ], "text": [ "Brass can hold an edge but not very well. Brass is a softer, more malleable metal than bronze so any edge won't keep as long. It also oxidizes more easily, forming the green-blue patina associated with it. The oxidation will ruin the edge much like how rust ruins iron edges. Brass was also discovered in 500 BC, later than bronze (3500 BC). Thus, sharpened bronze would have been a very common commodity when brass was being first used. It would be difficult to discover brass first because zinc is rarely found in a pure form in its natural state. You would need to figure out the technology to extract zinc and by then, you should have already figured out bronze.", "Metals are softer or harder depending on the ability of the nanoscale crystal structures their atoms form to slide across one another. Bronze is hard because the addition of tin creates extremely irregular patterns that makes movement of atoms very difficult. Tin is a lot heavier and bigger than copper, but zinc is virtually identical in atomic size. Thus Bronze is a lot more malleable." ], "score": [ 9, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
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cev5k2
How do treadmills and other machines track your hearts BPM by those silver things on the handle?
Technology
explainlikeimfive
{ "a_id": [ "eu596a4", "eu59ir6" ], "text": [ "The basic concept to be aware of here is what makes the heart beat. Our heartbeat is driven by an electrical signal generated by a small group of cells (sometimes called pacemaker cells) located within our heart. The electric pulse generated by this group spreads through the heart, causing first one part, then the other to contract and relax. (As an aside, this is why electric shocks are so dangerous; they disrupt that group of cells and stop our hearts from effectively beating.) ***However***, this pulse isn't confined to the heart; it spreads through the body, because our insides conduct electricity rather well. So, we constantly have an electrical pulse in our body as well. When we touch the silvery section of an exercise machine, the circuitry inside the machine can actually detect those minute changes in voltage caused by the pacemaker cells in our heart; from there, it can do some fancy math to separate one beat from the next, and arrive at an estimation of your heart rate.", "The silver things on the handle are electrodes. Think like those little pads that you see taped on a patient in movies and TV that give the hospital a patient's vital signs. those pads run a low level current (being sweaty makes them contact better, which helps get the reading, too) that checks the resistance of your skin. When you have a heart beat, it causes the blood vessels in your hands to expand and contract. This causes the resistance between those two pads to change a little bit, and the machine is able to track those changes and count them as heartbeats. It's worth noting that yes, there's a lot that can throw those readings off, and yes, they aren't always reliable- you wouldn't use them for something important like a life or death situation, but they are close enough for exercising to." ], "score": [ 12, 5 ], "text_urls": [ [], [] ] }
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cex0ju
How 64bit OS run 32bit programs?
Hey, How is it possible for 64bit OS to run 32bit programs? Didn't they compiled in different ways? If not does 64bit programs work for 32bit OS as well? If so what are the differences at all then? Thanks.
Technology
explainlikeimfive
{ "a_id": [ "eu5j18q" ], "text": [ "64 Bit mainly refers to the size of the memory bus on the motherboard. If a system has a 64 bit memory bus then it can address memory spaces that are much much bigger than 32-bit systems. It also means the internal registers in the CPU are 64 bits wide. That means the CPU can work on larger chunks of data at the same time. & #x200B; Running a 32-bit program is fine because they system doesn't need to use every single bit of the memory bus or every bit of the internal registers. & #x200B; Going the opposite way doesn't work because you can't fit 64-bit values into a 32-bit register." ], "score": [ 4 ], "text_urls": [ [] ] }
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cexq60
Why did it take the entirety of human history to even figure out how electricity works, but then only 200 years to get to where we are now?
It seems really insane that humans existed for about 100,000 years making very slow advancements over that time, until about 200 years ago when we managed to create things like batteries and dynamos. Then in .2% of our entire history as a species we went from hand cranked dynamos to controlling the entire world with massive amounts of electricity and machines that would seem impossibly complex to anyone from any point in history. What caused that type of sudden explosion in capability, and what prevented it from happening sooner?
Technology
explainlikeimfive
{ "a_id": [ "eu5rkr7", "eu5tnqp", "eu5tzyo" ], "text": [ "So I think where you want to look is the age of Enlightenment as the beginning of the rapid development of change. A big part of what drove scientific progress was the printing press, being able to reliably pass information across time and space helped the spread of ideas and as ideas spread and people could recreate others experiments aha now we are on to something. What prevented that from happening sooner the Church, and the Roman Catholic church had a stranglehold on society because of the Black Death. Something similar had happened in China before it happened in the west. An industrial revolution had taken place with mass produced goods like clothing and pottery and arms and so on. Before the Industrial Revolution population growth was constrained by food production. Giving people time away from figuring out where their next meal is coming from unleashed humanities potential for creating the word you see around you today.", "Since you could ask that about any discovery during the age of enlightenment, it's important to note the technological innovations happening at the time. Even before the Industrial Revolution the tools at the hands of scientists were getting really precise: this is the time of clocks, telescopes & microscopes, etc. A scientist planning an experiment could get copper wires or glass lenses made, or whatever they needed; none of the Greeks, as brilliant as they were, had this luxury. The printing press may have had a hand in it, as it had a hand it basically literally everything, but I think moreover it's the tools that helped scientists to discover these things.", "The huge difference was written language. No human could ever come up with special relativity, or laws of motion, or a microprocessor from scratch. But, now that we have written language, when one person learns something, he can pass that knowledge onto the next generation. This allows each generation to take the next step forward. Now, we also have a feedback loop that's making things progress even faster. A few hundred years ago, only the very wealthy learned to read or went to college. But now, as technology has improved, we can feed almost everybody, and educate most people as well. This means we will have more people coming up with developments than ever before (which in turn means we will have even more people in the future, developing things even more)." ], "score": [ 5, 3, 3 ], "text_urls": [ [], [], [] ] }
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cey2td
How does one computer use another computer's IP address to find and talk to it?
Technology
explainlikeimfive
{ "a_id": [ "eu5snx0", "eu5zhm0" ], "text": [ "You are very much on track with your post office analogy. I am going to focus on public IPs only and ignore private or internal IPs for this explanation, although the process is similar. For the most part, the internet is just a large group of independent machines that talk to their neighbors, and know how to get out of their network on to the next one in the chain. The pointer to the next one in the chain is called a gateway, and (again for the most part) all devices can have one. When a machine wants to get somewhere, it compares its target IP address to a list of its neighbors, and it if can't find it on that list, it asks the gateway to pass it on. The device that is that machine's gateway (most likely a router) then does the same thing until it reaches it's destination. This is an incredibly simplified explanation, because that would be incredibly inefficient if that's all there was to it. A public IP address has identifiers just like an address does in that part of an IP can indicate its country in order to get it pointed in the correct direction. Hopefully I shed at least a little light on your question.", "One computer doesn't \"find\" another computer. In fact, the internet works a whole lot like how you describe the post office working. Let's say you send a letter to someone in your neighborhood. That letter goes to your branch post office. The post master looks at the address and says, \"Hey, this letter needs to go to a local address. I'll send it out with tomorrow's mail.\" If you have two computers connected to your home router, and one computer wants to send a packet (a little self contained blob of data) to the other computer, your router gets the packet, recognizes that it's destined for another computer directly connected to it, and forwards that packet to the second computer. Let's say you're sending a letter to another town. The letter gets picked up and arrives at your local branch office. They see that its destination is not within their delivery area, so they chuck it in a bin with all the other mail, and that gets driven to a regional office. The regional office doesn't necessarily know about every street address, but they can look at the town and zip code of a letter and decide which branch office to send it to. Once it gets to the branch office, they look at the street address and get the letter to the correct mailbox. This is like sending a packet to a computer that's not in your home network. The packet arrives at your router. Your router looks at the destination address and sees that the destination is not for one of the two computers directly connected to it. Your router has a rule that whenever that happens it sends the packet up to your ISP for them to deal with it. Your ISP has routers that work like the regional office. They may not know what is at IP address 12.13.14.15, but they do know that there's another router that says they know where all the 12.13.14.X addresses are. So, your ISP sends that packet over that direction. Once it gets to that router, that router may be connected to 12.13.14.15, and can deliver the packet to its end destination. IP addresses, like street addresses, are hierarchical. The USA is made up of 50 states. States are divided up into towns and zip codes. Zip codes are divided up into individual street addresses. In IP addresses the *prefixes* form this hierarchy. IP address 12.13.14.15 is within 12.13.14.X, which is within 12.13.X.X, which is within 12.X.X.X. Different routers keep track of what to do with packets at these different levels of hierarchy. The nitty gritty details are more complicated than that, but that should roughly convey the general concept of how a packet finds its way through the internet." ], "score": [ 8, 4 ], "text_urls": [ [], [] ] }
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ceyjv1
If cellphones can record and stream in 4k quality in the palm of their hand, why do news cameramen use heavy multi-thousand dollar equipment to stream in 720p to their local stations?
Technology
explainlikeimfive
{ "a_id": [ "eu5uf1p", "eu5vhjb", "eu5ulrq" ], "text": [ "Well, that equipment might include zoom lenses (which your cell phone probably doesn't have), and it will also have a much larger lens so it will work better in low light conditions. Additionally, literally being heavier helps. A heavy camera has a lot of inertia which means that when you breathe and move around, the camera tends to move less than a lighter camera. If you tied a 50 pound rock to your cell phone, your videos would appear much smoother and less jumpy than just your cell phone alone... no technology required.", "4K doesn't mean anything about the quality of the video. All it says is the size of the video. Mobile phone companies use this to mislead you into thinking its better than it is. Companies with those cameras are often shooting MUCH higher bandwidth (i.e. better picture), with much superior lenses and equipment (better picture), and doing so often in uncompressed, or lightly compressed video (or lossless compression) video (better picture). They also have all sorts of tools, add-ons, and such that are necessary for truly high quality video productions, such as lights, sounds, view screens, an digital hookups, better low light conditions, zoom, and so on. These are amazing devices Your mobile phone has a shitty lens, bad views, and generally does a lot of compression on the video, losing a lot of quality that may be needed for use on a bigger screen for when it gets compressed again from cable/sat providers to your home. The TV companies need to film in the absolute best possible methods, bandwidth and such to be able to get the best picture to the end user after it goes through a whole lifecycle before it hits your eyes on your brand new 65\" TV.' So why don't they use 4K? Well, there's no point, no one is broadcasting in 4K except some specialized events, and it would take a lot of effort to get new equipment, and then reconvert to 720p or 1080i all of your content you shoot... and you shoot tons and tons of footage.", "Firstly, there's no zoom on a phone. A lot of the expense goes on lenses that allow zoom and for different looks for the footage which you are very limited with using a phone. Secondly, there's no point streaming in very high quality if the audience can't use it. It takes a good computer or a proper TV or monitor to show 4K footage" ], "score": [ 16, 15, 3 ], "text_urls": [ [], [], [] ] }
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cf55fv
Why do old movies and videos have this sorta staticky sound in the background and modern ones don’t?
Technology
explainlikeimfive
{ "a_id": [ "eu7hgh3" ], "text": [ "A lot of reasons: Old movies had the soundtrack imprinted on the film, it was analogue and intrinsically noisy - like cassettes, the same was true of video. Also copying the film to make a new print or change the format would introduce more noise. To deal with that Cinemas had quite sophisticated analogue noise reduction to minimize the background noise. Old TVs were pretty quiet so we weren't as aware of the background sound. Older equipment tended to have less treble and more bass so hiss was muted. Modern TV speakers are smaller have a lot less bass so we notice the treble hiss more. Modern recordings have digital sound which pretty much has no background noise like tape hiss - and copies are identical to the original so the hiss level doesn't go up when copied for modern recordings." ], "score": [ 3 ], "text_urls": [ [] ] }
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cf64vc
During the PS1 era, one of the upsides the N64 had that the PS1 didn't was that cartridges had no loading times as opposed to CD's which had more capacity but had to load all the data. Why do now the cartridges on the Switch, for example, have to make use of loading screens?
Technology
explainlikeimfive
{ "a_id": [ "eu7o5ic", "eu7obr4", "eu81us0" ], "text": [ "Back then, the ROM storage on the cart was about as fast as the RAM in the console. So there wasn't really a need to load data, because it was already readily accessible by the CPU. Since then CPU and RAM speeds have increased significantly. The speed of permanent storage has also increased a lot, but not by as much. Modern flash based carts are much faster than an optical disc or mechanical hard drive, but they're still significantly slower than RAM. So Switch games need to load data from the cart to the RAM in order to use it. I suspect for some games ported to the Switch from other consoles the loading times are really bad because they have been optimised for the other consoles. PS4/Xbox One in comparison to the Switch have much more CPU power, but slower storage devices. So for them it makes sense to compress data because then there's less data to read from the hard disk, therefore faster loading times. The decompression won't increase the loading times because it can do that while it's reading the next bit of data. So as long as the CPU is fast enough that it can decompress at at least the same speed it can read it from the hard disk, load times will be improved. If you port that game to Switch you might have a problem. Now the CPU isn't fast enough to decompress the data at the same rate its reading it, so that decompression might hold up reading the raw data from the cart. Maybe they try not compressing the data. That might improve load times, but those carts have a much, much smaller capacity than a PS4/XB1 game can use so it will be a struggle to get the game to fit. You face the choice of having to cut bits out of the game, reduce texture quality further, or have slower load times.", "Because they aren't the same kind of cartridges. Cartridges for older systems were tied directly into the system's memory bus - the cartridge was a read-only memory chip (ROM) that became wired in alongside all the other read/write memory chips (RAM) in the system. It would be like if PC games came on some kind of special DDR memory stick that you inserted onto the motherboard next to rest of the RAM. Because of this games had very little loading time because the data was **already** in memory. Games still had to setup a few things and copy some data into video memory but this could be done in under a second, especially if video rendering was momentarily turned off (black screen). Modern cartridges are basically SD cards and while they can be fast they aren't fast enough to be used like RAM. So just like with a disc data must be copied first.", "The biggest Nintendo 64 cartridge was 64MB. The CPU and RAM were slow enough that running the game directly from the ROM cartridge instead of loading it to RAM was feasible. These days, CPU's and RAM have dramatically increased in speed, so it's no longer feasible to run games directly from their media. The core game files need to be read from the media and stored in the faster RAM to keep the system from lagging horribly. Technically it could be possible to design a special system that can operate similar to how old console cartridges did, where the ROM in the cart interacts directly with the CPU. But this would overly complicate things and make the games very expensive. SD cards are way cheaper and more durable." ], "score": [ 10, 6, 3 ], "text_urls": [ [], [], [] ] }
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cf89tq
How the hell do Deep Fakes work?
Technology
explainlikeimfive
{ "a_id": [ "eu80roq", "eu8clmc", "eu80h0d", "eu8eqta", "eu84es7", "eu80hqa" ], "text": [ "Honestly, I know it's probably against the rules of ELI5, but I would recommend Corridor's Crew video on their Keanu Reeves deepfake to fully understand everything that's behind this. In short, you basically have to get an actor to play the body of the subject of deepfake, and train an algorithm to match the face of that celebrity you want in the scene to the body of the duble, you need to track the face of the celebrity trough interviews and movies though", "How Deep Fakes are generated is a system of machine learning called \"Generative Adversarial Networking\". It's a system which involves two networks that play a sort of \"information game\" against each other with a \"generator\" network and a \"discriminator\" network. The Generator Network is the one that maps out data patterns drawing from an information source (like drawing from a bunch of pictures of human faces and mapping the data to assemble a realistic human face of a person who does not exist) while the Discriminator network looks at the newly assembled data and attempts to figure out what it does right and wrong against the information source. It grades the Generator's attempt against the source and sends it back with new recommendations for it to incorporate into its next generative attempt. The Discriminator learns what a bad picture looks like and learns how to spot differences in order to offer better critique to the next generative attempt. The cycle continues until the discriminator network makes a certain percentage of error that it believes that the data is genuine and uniform (in other words, when the Generator \"fools\" the Discriminator enough to make it believe what it is seeing is a real image of a real person)", "Without going into the details of that actual technology - Computers have advanced to the point where we can create very realistic looking images using existing material. That has extended to speech as well, so for someone who is particularly well covered (like a politician) it isn't particularly surprising that a computer can create an image of them saying basically anything.", "The algorithm takes an image of face(with added algorithm to identify face in question), and transforms it into some bit string basically(it's not quite that but it's close enough and I can't think of a way to explain the proper way easily. It's close enough anyway). The model is trained so that it builds this bit string representation and then undoes it. Like, you get face, turn it into bit string, and then try to build face from that bit string again. To give an idea of how this training works, you basically score this result, and then change the algorithm so that it scores a little bit better next time. Which in this case is simple, because you just check if the result looks the same as the original image of the face. You can for example count how many pixels are the same. So far so good. But now, we split this algorithm into three parts. First, the part A that takes face, and turns it into a bit string. This is called encoder. Next one that takes bit string and turns it back into face is called decoder. We use two separate decoders. Say you want to change face of Keanu into face of Nicholas Cage. You use one decoder, B, for Keanu, and decoder C for Nicholas. We train it by taking A + B and feed it images of Keanu. We score results and tweak both A and B. We also use A + C and feed it images of Nicholas and tweak both A and C. As a result, A becomes capable of taking either Nicholas or Keanu face, and turn it into a bit string. B then is able to take that bit string and turn the bit string into Keanu face, and C would take that bit string and turn it into Nicholas face. So now we take image of Keanu, and feed it to encoder A to get a bit string, and then use decoder C to turn that bit string into a face of Nicholas Cage. This alone doesn't quite work that well, but we can use some mathematical trickery during training to force A to ignore all traits of faces it can see, if it can trust B or C can fill in the blanks. This works by adding extra scoring term during training, which gets kinda complicated, but the gist of it is simple, we want to make A not give B or C details of the face it sees that they should know just because they know the face belongs to Keanu(or Nicholas in case of C). Like, A shouldn't tell B how big a nose the face has, B should already know how big a nose Keanu has. What is the eye color of Nicholas? That's not information bit string should contain, because C learns that just by knowing who Nicholas Cage is. With that, you get bit string that contains only things like, which way face is facing, what's the facial expression, where are they looking, etc, and B and C paint their own actors based on these details. So that makes it possible to get this algorithm take one face and replace it with another with pretty much the same position, orientation, expression etc.", "Get lots and lots of pictures from different angles of someone, get some fancy AI that stitches those pictures onto the video depending on the angle of the face replacing it with the ones in the picture.", "You take a picture of person A and you put it in a photo of person B. If you do this naively, just by copying the pixels, the image is discontinuous at the seam. This makes the fake obvious. So, to make a better fake you use a machine learning program to reprocess the pixels near the seam, to make the seam invisible. One such program, as far back as 1997, was called Video Rewrite. The most popular \"brand\" of these better fakes is called \"deep fake\", so named because or a reddit user names \"deepfakes\" who produced and distributed some high quality examples." ], "score": [ 57, 20, 14, 7, 4, 4 ], "text_urls": [ [], [], [], [], [], [] ] }
[ "url" ]
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cfbnnz
Is 5g dangerous or is just fearmongering?
Technology
explainlikeimfive
{ "a_id": [ "eu8sh9a", "eu8y25h", "eu8y8q1", "eu8rvqi" ], "text": [ "Radiation, in terms of biological effects, can be broken into two main categories: ionizing and non-ionizing. Ionizing radiation is bad as it can strip electrons from atoms and molecules, breaking apart molecules and generally causing damage. Non-ionizing radiation doesn't have enough energy to strip electrons, if absorbed it primarily turns into heat. Non-ionizing radiation can be harmful, but it takes enough to basically cause a thermal burn (lasers for example can do that, or something like microwaving yourself). 5G is in the radio spectrum, well below in energy even visible light. It's in UV that radiation starts to become ionizing, and going further up the spectrum increases the energy further. This is why sunscreen, while appearing invisible to visible light, protects from sunburn. UV causes a radiation burn, and sunscreen basically is \"sunglasses\" for the skin that block UV. 5G is a higher energy frequency than 4G, but it is still pretty low compared to anything damaging.", "It's 100% fear mongering. There are people who believe that all radio waves are 'Dangerous radiation' and that things like WiFi and cellphones will give you cancer. This is because they hear the word \"Electromagnetic radiation\" and immediately associate it with ionizing radiation, the kind that things like X-rays and nuclear power plants create. 5G in the US will be on frequencies around 6GHz-50GHz. Ionizing radiation starts at 30PHz (Petahertz, which is above Terahertz, which is above Gigahertz/GHz).", "I believe the only credible issue with 5G networks is interference with weather satellites: URL_0", "No, it's safe. For the radiation fear mongering, you get in the range of solar radiation and above for any damage. Linus techquuckie video for more detail. URL_0" ], "score": [ 29, 10, 6, 6 ], "text_urls": [ [], [], [ "https://arstechnica.com/tech-policy/2019/05/5g-networks-will-likely-interfere-with-us-weather-satellites-navy-warns/" ], [ "https://youtu.be/lvhaVjpYm_M" ] ] }
[ "url" ]
[ "url" ]
cfcqb0
What is a core and thread in a CPU, and what exactly do they do?
Technology
explainlikeimfive
{ "a_id": [ "eu92b5m", "eu902v6" ], "text": [ "Imagine you are working in a restaurant, let's say a burger joint. A thread corresponds to a specific task, in our example we'll say there are the tasks: \\`make patty\\` \\`assemble burger\\` \\`fry fries\\` and \\`serve customer\\`. A thread is doing one of those tasks through to completion. Now, you can only have as many tasks going on at the same time as there are people working for you: the people are like cores and each is assigned a thread to work on. You could hire one person who has to constantly switch between making a patty, then assembling the burger, then making fries then serving it to the customer, but that probably would be too slow to stay in business. You could hire a faster employee, but you can only go so fast as a person. If you instead have 4 persons or \"cores,\" you can have one do each task at the same time as each other. Now you can increase the total number of customers served considerably, and can go further by adding more people to duplicate some tasks, such as multiple burger friers\" all while keeping within the limits of a single person and the tasks at hand. & #x200B; That is effectively how a CPU works. Programs give \"tasks\" to the operating system which switches them in and out between cores as needed to keep a responsive system. The biggest difference between a CPU and GPU is that a CPU is a few very fast cores and a GPU is a ton of relatively slow cores.", "A core is a single \"brain\" that can execute commands. Imagine it as several tiny CPU's pretending to be a larger one. Each core can execute code, work out calculations, and run programs; just like a \"bigger\" cpu would do. A thread is essentially the execution of a given task: it's the list of commands currently being processed by the computer. If you'd like you can imagine it as a literal thread of instructions running trough the core being executed. Each core can only work on a single thread at a time: if you want multiple programs to run on the computer they have to wait their turn. Your computer has a dozen different threads it switches in and out of processing hundreds of times per second, each running it's own program. However, if you have multiple cores you can have multiple threads processing at once: as each core can work on one thread by itself. This allows some degree of \"true\" multitasking within a computer. Of course programs actually have to be designed with this in mind: it doesn't matter how many cores you have or how many threads you can run at once: if your program never requests a new thread for computation it's always going to be a single thread being worked on by a single core." ], "score": [ 5, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
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cfd4yc
What is an algorithm? What makes it difficult to define?
I've heard and read multiple definitions of what an algorithm actually is. Often prefixed with "It's difficult to define but [...]". So I'm genuinely curious as to what an algorithm actually is and why it's difficult to define. Thank you.
Technology
explainlikeimfive
{ "a_id": [ "eu933kt", "eu93ml6" ], "text": [ "It's not really that difficult. It's a series of steps needed to do something. Long division could be called an algorithm.", "An algorithm is only difficult to define if the task it is solving is complex. Right? Let’s define some _preconditions_. There are two things in our universe. You and a sealed envelope. You are seated cross legged. The envelope is directly in front of you. The _post-condition_ is an opened envelope. This algorithm is the OpenEnvelope() algorithm. These are the steps: 1) Command your body to pick up the envelope. 2) Command your body to slide your pointer finger under the left lip of the envelope. The point where the fold happens and a slight gap exists. 3) With your finger in the gap, command your finger to make a swiping motion to the right thus lifting the flap as your finger moves. 4) Continue this motion until your finger passes the rightmost side of the envelope. The envelope should be opened. The complexity you’ve mentioned exists because our algorithm is imperfect—rather it is incomplete. How do we will our body? What is the gap? A swiping motion? Even this very basic task is difficult to define fully. Often algorithms are discussed in scope of computer programming. Where humans can fill in the blanks and infer things that are unclear, computers cannot." ], "score": [ 11, 5 ], "text_urls": [ [], [] ] }
[ "url" ]
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cffedb
How the heck does 3D printing actually work? Can you print using different materials (metal, wood, etc)?
Technology
explainlikeimfive
{ "a_id": [ "eu9jl77", "eu9lvau" ], "text": [ "Little pieces of material are fused together. It only works for fusable materials like plastic or metal. Wood is cellular life, a completely different sort of thing.", "3D printing takes a model and makes thin slices of it, called layers. Think of it like your normal paper printer; It goes left and right to make a line then moves the paper forward for a new line making your document. A 3D printer is just doing the same thing in a 3rd axis. Using heated plastic it forms these layers with strings of plastic forming the model. As for wood or metal, we do indeed have those printers. They work differently. The metal or wood is put into a powder form mixed with binder. Since your using powder you can just make strings of like the plastic printer. Instead the binder is shot with a uv light/laser a forms the layers that way." ], "score": [ 7, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
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cfg0sx
how exactly do one way glass work, and how can you see from a tilted glass in a car but can't see from the outside?
Technology
explainlikeimfive
{ "a_id": [ "eu9o2ut" ], "text": [ "It's just a matter of refraction and reflection. \"One-way glass\" is just normal glass, but usually a little thicker to provide more chance for light to bounce. But basically one side is in dark and the other room is in light. Just like it's hard to see into a house during day, verse the ease during night. The brighter side is having light reflected back at itself making it hard to see into the shadow." ], "score": [ 5 ], "text_urls": [ [] ] }
[ "url" ]
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cfh85o
how do calculators actually work?
Like the title says I’m just curious how tf calculators work.
Technology
explainlikeimfive
{ "a_id": [ "eua1p8i", "eua6nmx" ], "text": [ "Calculators are complicated circuits operating in binary. Binary is a way of counting using only two numbers, 1/0: 0000,0001,0010,0011... For simple operations the calculator utilizes a so called full adder: a circuit that compares 3 inputs to two outputs. You can imagine it like written addition. There are 3 inputs: x,y and carry in/over. X and y are decimal places of your compared numbers, and ci is the carry out of the last decimal place. You start comparing the first number, if in=0: out & co=0, if in=1:out=1 & co=0, if in=2: out=0 & co=1, if in =3: out=1 & co=1. Then you put the next decimal point in and put co into ci. Repeat that until all decimal points are accounted for and save all output bits. That's your new number. It gets way more complicated when subtracting and multiplying, but they are all based in adding.", "/ubus99 wrote a good explanation. If it's hard to wrap your head around, it might help to see someone build an adder, which they do with dominos in [this nifty video]( URL_0 ). He also has a longer video where they constructed a calculator by hooking together multiple adders out of dominos, [which you can see here.]( URL_1 ) An actual calculator does the exact same thing, just with wires and transistors." ], "score": [ 8, 5 ], "text_urls": [ [], [ "https://youtu.be/lNuPy-r1GuQ", "https://youtu.be/OpLU__bhu2w" ] ] }
[ "url" ]
[ "url" ]
cfmg9x
How do the manufacturing companies ensure that the insides of the food packaging packets are thoroughly cleaned ?
Technology
explainlikeimfive
{ "a_id": [ "eub1zhp" ], "text": [ "Depends on the package, but there is usually some sort of cleansing step right before filling and sealing. Take bottles for instance. On the bottling line I worked at a brewery, empty bottles first entered a sanitizing machine that flipped them upside down and blasted them out with peroxide and water, then were filled and sealed within seconds. Plastic bag type packages usually come off a huge roll of what is basically a plastic tube. It was manufactured in a fairly clean environment, and it is pretty much impossible for stuff to get inside until it comes off the roll and is cut, filled, and sealed in seconds." ], "score": [ 5 ], "text_urls": [ [] ] }
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cfn4gq
why can a high speed 4g signal reach me anywhere but wifi has trouble reaching me in the next room?
Technology
explainlikeimfive
{ "a_id": [ "eub29wv" ], "text": [ "There are 2 factors to consider. First is your surroundings. Radio waves, like a 4g signal or wifi are just electromagnetic radiation, like light. They pass through some things well, but are blocked by others. Having multiple walls, or a big HVAC unit, or a metal building between you and the transmitter can block either signal. Compare that to being outside, where your phone might be on direct line of sight with the 4g tower. The other thing to consider is the size and power of the cell tower transmitter vs your wifi router. A cell tower transmitter can be bigger than a person, with a dedicated high voltage line supplying enough power to transmit signal for miles. Your wifi router is much smaller, plugged into a wall outlet, and only designed to transmit 100 feet or so." ], "score": [ 4 ], "text_urls": [ [] ] }
[ "url" ]
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cft1l9
How is it possible that games like Spore (the one where you make creatures ect.) are able to have full animations for things that you only just made.
i can use the same parts on a creature and have them look wildly different yet it still has a decent animation for its actions.
Technology
explainlikeimfive
{ "a_id": [ "eucez3u", "eucaogb" ], "text": [ "The big buzz word at the time was \"procedural generation\", which is a [commonly asked about topic here]( URL_0 ). TL;DR: you program in a set of instructions that the game will use to make decisions. It's easy to explain this in building how a world looks. The best example is a Minecraft world. You give the game a seed, which is a defined starting point. Then the game follow instructions like: if there is a block of stone *here*, then put another block of stone next to it; unless the stone is more than Y distance high, in which case, put dirt next to it. If you have a such and such number of stone blocks together already, then the next block is a coal block. The instructions can get pretty complicated, but the game follows them carefully. In fact, when you load up a saved game in Minecraft, it doesn't actually save your whole world. It just remembers the seed you gave it the first time and rebuilds the whole thing from scratch, with the changes you made. Similarly, Spore starts with some basic instructions for how the animal's limbs should behave. If there is a thing *here*, call it a leg. Legs move in *this* way: if the leg is positioned *here*, it moves *there* and it can't pass through other parts of the creature. If it has a thing sticking out of this part, call it an *arm* and it moves like *this*. The programmers experimented a lot and came up with the best instructions that could apply to whatever they could think up. But, proving that the mad, unbridled creativity of thousands of players will always be greater than the imaginations of a small handful of developers, the basic instructions will never be good enough for [all possible shapes of creatures]( URL_1 ). The biggest downside of procedural generation is that it makes a lot of things look *good enough* but there will also be a lot of things that look *not great*. Deliberately programming the movement of creatures, on the other hand, means you can make them look *really awesome*, with the downside that your programming will only apply to that one thing.", "Afaik there's a simple Skeleton structure with the animations baked into it that is invisible, which controls how the character model works. As an example for how it can work with more than 2 legs, The animation for the legs is copied to each set of legs your model has, and has an offset on when the animation plays so the legs look like they move fluidly. I may be wrong, please correct me if you know better than I do!" ], "score": [ 13, 12 ], "text_urls": [ [ "https://www.reddit.com/r/explainlikeimfive/search?q=procedural+generation&restrict_sr=on&include_over_18=on&sort=relevance&t=all", "https://www.youtube.com/watch?v=ajcs9X5RTLs" ], [] ] }
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cfu2pv
why don’t companies do their sensitive work on computers that are not connected to the internet, and therefore unhackable?
Technology
explainlikeimfive
{ "a_id": [ "eud11lo", "eucrkzd", "eucifmt", "eud2pwh", "eucjz51", "euctio4", "eud765r", "euda88f" ], "text": [ "They do. But then you lose all the advantages of having networked computers. It slows things down. Now if you need information from another department, you have to get it the old fashioned way, sneaker-net style.", "Some agencies do sensitive work on 'air-gapped' systems that are not connected to external networks. Security levels vary by agency, from 'no public Internet access' to 'no outside networks, ever, period'. Theoretically, this makes those environments less hackable. I have walked OS patches on CD-ROM (NOT CD-RW) into secure facilities a few times, when I've been searched for USB sticks and cell phones and watched closely by staff with blinking red lights overhead telling everyone that I'm a potential threat. Never mind the fact that I'm the guy that built the OS patch - and if anyone was capable of doing something bad as the root user, it would be me. tl;dr - it's all about expense, and your paranoia level.", "Air gaped. Yeah. A lot of computers probably are. But if you need to share information between two computers, there would be an internet connection. Emails can always be hacked.", "Security is often a trade off between safety and useability (as well as cost of course). In particular, air gapped systems have severe disadvantages precisely because they are disconnected. Looking up public information, interacting with your community of peers, emails, etc. is all made more difficult. The increased security of air gapped systems is only worth it in certain circumstances. Companies usually hope their other security measures (firewalls, encryption of files, etc.) are good enough to not be victims of untargeted attacks (most normal worms and viruses that live in the \"wild\"). This is the case for most small and medium business enterprises and perhaps some multinationals. Organisations who feel at risk of targeted attacks (some branches of government, law enforcement, defense contractors, perhaps some firms with a lot of high value industry secrets) can and do take more security measures, including air gapped systems.", "Most companies have air gaped networks, for their most sensitive work. The US government operates a [huge one]( URL_0 ). It's a lot of extra work. Employees complain that it reduces their productivity when they can't watch cat videos. For many companies, their \"sensitive work\" isn't worth it.", "They do. I’ve done consulting for pharmaceutical companies, they have more security than banks", "I used to work for a company which did a lot of UK government work and most of their systems were IL3 accredited - essentially each contract required its own separate and secured entity, but could have limited network interconnection using VPNs over our internal non accredited network. There were loads of controls and cost quite a lot to manage, maintain and get audited on a regular basis. We built an IL5 accredited environment which had secure cages within a hardened room that was designed as a faraday cage with things like anti drill walls. I understand they had to do something special with the power into the room to ensure isolation too. No outside network links, only accredited personnel inside, no removable media. If you worked on that contract, you could only do work in that room and couldn’t bring anything in or out. I wasn’t accredited so have no idea how the guys did patching, but I do know that they only ran the contract for about 18months as it was too expensive vs the contract value.", "Imagine instead of sending the work to another computer over an ultra-encrypted network, you stick it on a flash drive and walk it over to the other computer. The chances the flash drive gets lost or stolen are probably higher than the chances the encryption gets cracked" ], "score": [ 931, 536, 47, 42, 41, 10, 7, 3 ], "text_urls": [ [], [], [], [], [ "https://en.wikipedia.org/wiki/SIPRNet" ], [], [], [] ] }
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cfvgpy
How do apps or websites that have offerwalls know that you installed and ran an app on your device or completed the offer?
Technology
explainlikeimfive
{ "a_id": [ "euct4h8", "eucti1p" ], "text": [ "There’s usually account information associated, either with you or the app. When apps run, they can register details on your computer or device, and, of course, “call home.” Some token or tag will be shared. It’s really that simple.", "this is a pretty broad question, as there's a number of ways this can be (and is) done. here are a few: - advertisers dropping cookies on your system, and the offerwall checks for them. - using javascript and css to check the link color of a site to see [if you visited it]( URL_0 ) - calling a web services on the referred service to see if your ip address and fingerprints have completed an offer. this is most of what i see now, as the offerwalled site is getting something for referring you, so the referred service has to track who referred you. - this is *huge* in the porn website world. there's a lot of people who get rich doing nothing but making clickthrough referral sites. - in the case of something like an instagram or twitter follow or like, the offerwalled site simply checks with instagram or twitter to see if you followed or liked the account or post they wanted you to." ], "score": [ 13, 6 ], "text_urls": [ [], [ "http://lcamtuf.coredump.cx/css_calc/" ] ] }
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cfwkdi
How did Super Mario Bros on the NES look blocky, have no detail, and lack a bunch of features; yet Super Mario Bros 3, also on the NES, with the same hardware, have a fully fledged world map, Siginificantly higher quality sprites, and more content? While on the same cartridge?
Technology
explainlikeimfive
{ "a_id": [ "eud0js7", "eudgc6l", "eudr55l", "eudlm15", "eudjtm6", "eudltr8" ], "text": [ "Memory hardware inside of cartridges advanced precipitously in the five years between the release of Super Mario Bros. & Super Mario Bros. 3. The limitations on the quality of graphics were almost entirely based on the amount of available storage in the carts.", "The NES cartridge connector connects several NES buses to the cartridge. One bus connects the PRG ROM. This ROM contains the program and game data. It has 15 address pins so it can address up to 32KiB. Another bus connects the CHR ROM. This ROM contains tile data: 8x8 squares of 4 colours. There are 4 palettes for backgrounds, and another 4 palettes for sprites (0 is always the transparent colour). One byte is used to select which tile is displayed so there are 256 tiles available for backgrounds, and another 256 tiles for sprites. You need 8KiB to store all this data (2 bits per pixel \\* 64 pixels \\* 512 tiles). & #x200B; SMB uses the CHR rom at it's maximum capacity. Some sprites like the goombas are in fact the same half twice with one half flipped to save space. Some NES games uses extra hardware called \"mappers\" to circumvent it's limitations. It allows mapping a subset of a bigger ROM into the address space. SMB3 uses the MMC3, uses a 128 KiB CHR ROM a 256 KiB PRG ROM and 8KiB of RAM (used for level data). With all this extra memory available, you can have all the animations, world map and stuff you don't have in SMB1. EDIT: typo", "To add to what others have said, It takes awhile to really figure out how to utilize consoles to there full potential. Look at some of the first PS2 games and then look at some just 2-3 years later. It is hard to believe they are on the same system.", "To add to this, Super Mario Bros was originally on a floppy disk in japan, before capcom discovered how to increase the storage of a cartridge with Makaimura(Ghosts n Goblins)which effectively killed off the Disk System in Japan(The western NES has a serial port on the bottom of the system for the planned western release of the disk system) & #x200B; iirc the floppy disks could only hold a max of 144kb whereas the largest licensed NES game kirby's adventure was 512kb for the program rom and 256 kb for the ram", "Also games almost always look better mid to late gen of a console. Compare heavenly sword to uncharted 2/3, last of us or gran turismo. The developers learn tricks over the years even if the hardware didn't change to push a better looking scene.", "How do you become better at maths over time, despite the rules of math remaining the same, and you being the same person? You learn more. You work out faster ways to do the same thing. Programming is the same way. Also; the cartridges are unlikely to have been the same; as time moved on memory became cheaper and its much more likely that SMB3 had significantly more available memory than SMB1. Not to mention things like co-processors such as the later SuperFX chip for the SNES cartridges." ], "score": [ 758, 54, 18, 12, 10, 5 ], "text_urls": [ [], [], [], [], [], [] ] }
[ "url" ]
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cfwswc
What is Usenet? And how does it work?
Technology
explainlikeimfive
{ "a_id": [ "eud2ea7", "eudeyz4", "eudli88" ], "text": [ "A collection of forums (called newsgroups) that was bit like really old version of Reddit. It's a bit hierarchical, so groups kind of contained other groups - so One called \"alt.subculture\" might have a sub group called \"alt.subculture.punk\". In the past it worked by internet providers synchronising the contents of the newsgroups between themselves, then as a user, you would access the newsgroups directly from your internet provider. As its distributed in this way, not all of the servers held all of the newsgroups. Nowadays it still exists of course, but is accessed less though your internet provider and more by specialist companies that give access (often for a fee), it's not as popular with the general populous of the internet as it used to be, as webpages and online forums took over for ease of use, etc.", "Used to be an online forum like reddit with different subreddits and even subreddits of the subreddits before the world wide web. Back when the internet consisted of email, ftp, usenet. Then gopher and irc came along, then eventually the www. Now most isp's don't support it anymore but you can pay certain ones for access. As others said it's unmoderated so anything can be posted there and I mean anything.", "One use for it was for fan subs of anime. People would use it to request and offer up subs. You would send someone a blank tape( VHS tape not the sticky kind) and they would send you back subtitled anime. This was organized on usenet. How far we have come. & #x200B; I also recall a major attempt to ruin all the movie forums by posting spoilers in the title of the posts. That lead to only the moderated movie forums surviving on it. & #x200B; It was also really big for sex stories of all types. This I know still exist, heh heh, but all the stories at least for the moderated version are also posted on the web. I have no idea why people haven't moved on from it, maybe less moderation." ], "score": [ 44, 5, 5 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
cfxkgf
How does Wifi actually work?
Technology
explainlikeimfive
{ "a_id": [ "eud8732" ], "text": [ "It's a radio modem. It uses radio waves. It interprets the signal sent/received over the radio waves as data. The radio waves in question are what's called \"non-ionising\". They can't do you any damage. If they could, you'd be dead already from a million other things, not least naturally occurring radio waves. If anyone ever says \"Yeah, but they use \\*this\\* frequency\", ignore them. It's much more to do with emitted power than frequency, and the frequencies in use have been in use for things for hundreds of years. Pointing the finger at just frequency is like literally saying \"Yes, but the car is \\*BLUE\\* so it must be more dangerous\". (Microwaves ovens use a very similar frequency to conventional wifi, which is still non-ionising, for instance. But so does your car parking radar. It's all about the emitted power).\\* The power of your average wifi point is literally its most limiting factor, in regulatory terms, and the reason that you can't just talk across the city with them. Compare and contrast to, say, the power needed to broadcast similar data on similar frequencies from miles away to thousands of mobile phones (and for them to talk back). Even there, though, mobile phones, in ordinary usage, over the entire population are still \"safe\". Nobody has ever conclusively proved anything else. And yet mobile phones would be \\*much\\* more dangerous than Wifi if there were a problem, and we'd notice it there first. Mobile phones are run from towers pumping out orders of magnitude more power, that you walk past every day, and the handsets pump out loads of power and are \\*right next\\* to your head when they do so. If there was a problem, we'd know about it by now. Wifi is a tiny weak signal that you don't have up against your head and can barely make it through your house, let alone a city. I work in IT and this stuff \\*pisses me off\\*. I was once told, to my face, by a parent in a school I worked in: \"You do know that you're frying children's brains, right?\". She wouldn't listen. And then promptly stuck a phone to her ear, bundled her child into a huge SUV-like car and drove off, still on the phone. The smoking of this generation will be vaping (when you find out that all that stuff you've been burning and inhaling came from a sweatshop in China who substituted anything they liked to make it taste nice - breathing smoke of any kind into your lungs isn't good for you). Then it'll be plastics and the stuff in them (e.g. BPA, etc.). Then it'll be a range of pharmaceuticals (that are massing in nature to be present in every fish caught, etc.). But they will be nothing compared to the things that humans will continue to do deliberately and knowingly. Like burning oil and coal, breathing in exhaust fumes (remember the diesel scandals?), etc. (\\*) most ionising radiation, like X-rays, etc. are damaging even at relatively low power - because the frequency is so high. But they're not even close to the frequencies being used for such things." ], "score": [ 3 ], "text_urls": [ [] ] }
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cfysdi
How do websites like YouTube store billions of hours of videos in various qualities for years, while still allowing people to access and watch the videos at any moment?
Technology
explainlikeimfive
{ "a_id": [ "eudegi9", "eudgdto" ], "text": [ "> I’m picturing a huge room with hard drives everywhere with all of the videos on them but I’m sure that’s not right lol. Nope, that's pretty much it; it's called a ['data center.']( URL_0 )", "Data centers, and we can’t build them fast enough. They pay us ridiculous money to work 7 days a week 12hours a day. Look up David and Goliath data center in Virginia I’m pretty sure there’s a YouTube video on it." ], "score": [ 55, 10 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Data_center" ], [] ] }
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cfyv01
In computer science, how do packets get lost in the first place?
Technology
explainlikeimfive
{ "a_id": [ "eudeuzh" ], "text": [ "Many ways including: 1. Packet filtering due to policy rules 2. Routing errors causing loops resulting in the time to live TTL expiring 3. Link errors causing corrupt frames that can not be self repaired 4. Queue buffers getting full on routers 5. Software errors on routers such as the bloody VSS issue with have on our 6870XL at the moment and Cisco Tac are being slow resolving it ( not an ELI5 but a rant )" ], "score": [ 9 ], "text_urls": [ [] ] }
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cg08jh
Why can’t we predict earthquakes at all?
My understanding is that Earthquakes are caused by tectonic plates under the Earth’s surface colliding. They say we never know when they are going to happen. Why isn’t it possible to create a device that can track the movement of tectonic plates and know if they are on course to collide?
Technology
explainlikeimfive
{ "a_id": [ "eudorfs" ], "text": [ "The plates aren't in constant motion and you can't just see a collision coming. They are pressed against each other and stuck there for long periods as pressure builds up. The force pushing the plates has to overcome the friction of the two plates rubbing together. Eventually, there comes a point where the pushing force is greater than the friction and there is an awful lot of energy released. Imagine pulling on something that anther person is holding. You build up energy pulling on the item, then they suddenly let go of it." ], "score": [ 3 ], "text_urls": [ [] ] }
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cg0yay
Why do TV manufacturers turn on the "Soap Opera Effect", or motion smoothing, by default?
Technology
explainlikeimfive
{ "a_id": [ "eudxg37" ], "text": [ "Because they use it in the advertisement, and a certain percent of consumers are too dumb to enable it. Because it’s more likely people who care will seek out disabling it, and people who don’t know any better will get mad if they don’t know how to use it. Just like how my last phone came defaulted to a super vivid awful display setting and nothing looked real, or how most TVs I’ve used look like trash when I plug a computer in because the sharpness or contrast is turned up to high. All these are things designed to make the image look “more appealing”. It would be nice if movies just made the jump to 60fps. I understand many of the reasons why it doesn’t make sense but you don’t get the soap opera effect when the extra frames are actually real." ], "score": [ 3 ], "text_urls": [ [] ] }
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cg1463
With mobile processors becoming smaller and more efficient, why aren't we using them in laptops? Especially Chromebooks would perform well I'd think.
Technology
explainlikeimfive
{ "a_id": [ "eudwul2" ], "text": [ "The first thing is that the processors are pretty different. Laptops and \"normal\" computers use x86 processors and mobile devices use ARM processors. Think of this as that they speak different languages, and can not understand each other. You can write a program for x86, but it won't work on ARM because the program only \"speaks\" x86, and vice versa. [There are some technical ways to work around this issue, but thats a whole different complicated topic, and has many drawbacks] Secondly, the mobile processors are highly designed and optimized for mobile devices. That means their goals are to be constantly on, and draw as little power as possible, produce as little heat as possible while being \"fast enough\". I did not say fast, I said \"Fast enough\". They need to keep their speed in check, otherwise it will draw too much power or get too hot. These are fast, but think of them like fast like a racecar. x86 laptop cpus on the other hand also want to draw low-ish power, but they can draw way more and still be fine. They want to reduce heat, but they can have some serious heat and still be fine. This allows them to increase speed an incredible amount. They are god damn rocket ships compared to that racecar. It's that big. So can we use mobile ARM processors in laptops? Sure, the idea has been floated around for a decade at least, but it seems far less interesting than having a super powerful x86 processor, that can run all the traditional computer programs... so we instead use these mobile processors for stuff like tablets." ], "score": [ 8 ], "text_urls": [ [] ] }
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cg3c53
How does oxygen work in submarines when underwater?
Technology
explainlikeimfive
{ "a_id": [ "eueag98", "eueak98" ], "text": [ "Depends on the submarine. Non-nuclear submarines have a snorkel they use to pull in air for their primary engine. If they want to submerge completely they typically switch to an electric engine and typically the batteries used to run this will last shorter than the air in the submarine will keep the crew going, though some commercial submarines don't have an electric engine and therefore just can't stay submerged and running more than a few minutes before both engine and crew dies. Nuclear submarines produce their own electricity in such vast quantities that they can afford to spend some ripping apart water at the molecular level to produce oxygen and hydrogen.", "Subs generate their o2 by separating water into hydrogen and oxygen, the hydrogen is dumped through a bubbler vent along with excess co2. In an emergency they can burn oxygen candles too. Or they can come to periscope depth and suck fresh air from a snorkel." ], "score": [ 7, 3 ], "text_urls": [ [], [] ] }
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cg3w7w
How cartoons that are handdrawn (Not Flash animated on computers) are made and then put on TV
I know animation is based on showing similar frames in a rapid succession. But how do you get this on Tv in a manner that fluently occupies the entire screen?
Technology
explainlikeimfive
{ "a_id": [ "eueg9lb" ], "text": [ "The animator draws out each frame of the character on each paper using a special lightboard table. The drawing table usually has a circular hole in the middle for the light under a plate of glass. This enables the animator to draw consistent motion when drawing over his previous sketches. Another artist takes these sketches and traces them using colored paints onto celephane overlays- again, one sheet per frame of movement. These celephane overlays are then taken to photography where each celephane overlay is placed on painted background. They are then captured by an overhead camera, one exposure = one frame of motion. This is overly-simplified explanation into what has been the format for fifty years until the evolution of CGI and computer animation in the mid-90s. From the 1930s, studios such as Disney and Warner Bros had factories of animators and artists. There would be one animator per character per scene. So, for one 90-minute movie, you would have had to have an army of animators working months. To keep the style consistent between all these animators, you need a director to work with character-designers and storyboard artists to come up with a visual style. Chuck Jones of Warner Bros is a fine example. You can always see his style in the characters, even though other animators were drawing out the motion." ], "score": [ 5 ], "text_urls": [ [] ] }
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cg6w4b
does using internet/wifi use up SSD's write cycle, if not what aspects of it does? Does viewing images/videos (not downloading them) use up these cycle?
Thank you all for your helpful replies,
Technology
explainlikeimfive
{ "a_id": [ "euf65pm" ], "text": [ "Yes, data is written to your drive when using the internet. That said SSDs life expectancy is longer than you might think so using one normally should last for the life of the PC with little trouble (5 years or so). Also, some SSDs, like Samsung, have a utility which partitions off some percentage of the drive (you can choose, default is 10%). This extra partition is used when parts of the SSD cannot keep data anymore. This effectively extends the life of the drive." ], "score": [ 5 ], "text_urls": [ [] ] }
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cg890o
Why does nuclear fusion create so much energy, and why can't use it (yet?) to produce electricity?
Technology
explainlikeimfive
{ "a_id": [ "eufb73n", "eufb6f7" ], "text": [ "TLDR: Current generation reactors don't produce enough energy to be self-sustaining, ie they use more power than they produce. Nuclear fusion reactions release a lot of energy for a small amount of mass. That makes fusing hydrogen much more energetic than burning things like coal. The problem with Nuclear fusion is that maintaining a reaction requires a lot of energy. Fusion occurs at very high temperatures and pressures, and maintaining that kind of environment without the mass of a star requires a lot of energy input. The point where a reaction generates more power than it consumes it is considered self-sustaining. Some point after that it will be useable to generate electricity. Current reactor designs aren't self sustaining, but technology is always improving.", "The amount of excess energy in the form of heat that’s produced when you fuse two lighter atoms to make a heavier atom is phenomenal. That amount of heat and ways to sustain its containment are still being worked on for continuous operation, not to mention as far as I know at the moment, the amount of energy required to jump start the process is quite large. We’re learning, basically." ], "score": [ 17, 3 ], "text_urls": [ [], [] ] }
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cg921s
How do powerline adaptors (allows you to connect to the internet via a power outlet) work?
Technology
explainlikeimfive
{ "a_id": [ "eufgmwc", "eufm8l0" ], "text": [ "Power lines are just like any other wire, and devices can communicate over higher frequencies than the AC power (50 or 60Hz depending where you live) which is its originally intended use. It’s kind of the same concept as DSL, where plain telephone service used up to 3kHz and DSL utilizes like 4kHz to 6MHz or something. However, Romex (or whatever power wire) is not great for super high frequencies because it’s not twisted or shielded like network cable, but there’s some trickery with error checking and noise filtering that gets the signal workable up to a certain data rate. Unfortunately, I believe there’s a limitation that the source and destination have to be on the same circuit or at least two circuits on the same Hot buss bar in the service panel (typical US residential has two 120V Hots out of phase, so as to provide 240V).", "The general idea is that an ether media can carry signals of several different frequencies at the same time, and they won't interfere with each other. A power line cable carries a VERY STRONG signal at 50Hz or 60Hz (depending on which country you are in...) that is used to power feed the lights, the vacuum cleaner and whatnot. But that means that the only signal that is supposed to be in the cable is that 50 or 60Hz signal. And the entire rest of the frequency spectrum is available for other uses. For this purpose, there are a few very old and standardised bands for power line communication. Three of them, to be exact. They are named with simplicity in mind and called Band A, Band B and Band C. Band A is a long distance communication band *at a very low frequency*, that is allowed to transmit with a pretty high voltage. So that it reaches far. And it does. In mint conditions, it's even able to bypass power grid transformers and pass several voltage level changes. For this reason, it's ideal for the power companies own signalling equipment. And for that reason, it's use is restricted. The use of Band A is forbidden unless you have permission from the power company. Band B has a frequency that is a bit higher, and it's intended purpose is *interproperty communication.* When you have...say...two buildings nearby each other that have just one maintenance crew, and want a simple way for the HVAC in the other building to be controlled from the maintenance office. It's free for all to use. Or when you happen to own fifty or so cabins scattered around a field, and want them all to send alarms when something is wrong with ventilation, or the temperature is too low or a sensor detects water behind the sink. That kind of usage. Band C is for *intraproperty use*. Conveniently making use of a frequency band and a signal strength that is usually not able to make it's way out in the power grid and into your neighbours house. It's also free to use. The thing with the Band standard is that it doesn't really care how fast you communicate on the band. Or if you even bother to send data. Analogue connections are fine too. The standard just specifies that signalling equipment must listen in on the media for a number of milliseconds before it starts to transmit, to avoid interfering with other equipment. If you can build something that sends data at almost ridiculous speeds that makes use of the band, then you are allowed to sell it. As long as it uses the right band, and knows how to shut up when something else tries to talk." ], "score": [ 4, 4 ], "text_urls": [ [], [] ] }
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cgcuff
How do we keep in contact with spacecraft such as Voyager 2 that are at the very edge of our solar system?
Technology
explainlikeimfive
{ "a_id": [ "eug7kgu", "eug7jci", "eug7sx8" ], "text": [ "With very big dishes on Earth, and very sensitive receivers that can find the tiny signal. Fun fact: the Voyagers' radio transmitters are 20 Watt -- which is the same power as the bulb in your refrigerator. So we're effectively looking for a flickering fridge bulb, 19 billion kilometres away...", "Big. Honking. Antennas. Also, very slow and methodical communication. Distant satellites compensate for the weak connection by sending data slowly, which is why it can take months to download the data samples that the probe can take in just a few minutes.", "There are a few factors which makes us able to do this. Firstly we use enormous antennas here on Earth to send and receive signals that far away. Secondly we use the latest in signaling technology that is distinct from backgroud noise even if it is much weaker. We also use a very low bitrate so that the signals are very unique and therefore easy to pick out." ], "score": [ 38, 8, 3 ], "text_urls": [ [], [], [] ] }
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cgdk02
What stops battery technology progressing faster?
Always hearing about some great idea someone had but we still seem to be iterating on Lithium Ion so I’m curious, what are the biggest problems?
Technology
explainlikeimfive
{ "a_id": [ "eugb79r" ], "text": [ "It is just really difficult to hold large amounts of energy reliably, cheaply and safely (all of which are required for consumer electronics). Higher capacity batteries exist in labs, but very often they fail on one of those three dimensions: - They are susceptible to thermal runaway, where they can explode in a non-trival number of cases. All batteries are susceptible to this, but the existing odds are very, very low. An experimental battery that explodes in 0.001% of charge cycles is still too dangerous for consumer electronics - They aren't reliable. Some high capacity prototypes will wear out after a hundred charge cycles (or less). Your phone battery holds capacity for _thousands_ of charge cycles, so a hundred isn't good enough for consumer electronics. - They are expensive. Just because we can create a high-capacity, safe and reliable prototype doesn't mean we can scale that to inexpensive manufacturing. If a \"perfect\" phone battery exists, but costs $5,000 per unit to manufacture, it won't be used." ], "score": [ 6 ], "text_urls": [ [] ] }
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cgik8k
How do the different wireless networks do not collide with each other and decrease their intensity or increase it according to the case?
Technology
explainlikeimfive
{ "a_id": [ "euhi82b", "euhnwjg" ], "text": [ "Actually they do collide. I'm case of WiFi in your house, it use 2,4 or 5 GHz signals. But it doesn't use exactly 2,4 or 5 GHz but rather a slightly different frequency, like 2,389 or 4,997. With that the network \"trys\" to avoid to use the exact same frequency as a near by network and to avoid on this way to \"collide\" with each other. There won't be a total signal loss if two networks send on the same frequency, but the packet loss and therefor the speed and reliability will suffer.", "Even within the same Wi-Fi channel and between different networks that share the same frequency bands (for example Bluetooth and Wi-Fi) there is an additional collision proofing technology at play. Spread spectrum encoding. Each device uses a band of frequencies not just one and the signal is speed across that band in specific patterns that are designed to not collide with each other so that at any given time one device might be using the lower frequencies in the band and then the highest and then the middle ones in rapid succession. Only the other device that is trying to listen knows what the pattern of this switching is so that many devices can share the same channel. In the off chance there is a collision, the devices move on to the next step in the sequence and recover." ], "score": [ 3, 3 ], "text_urls": [ [], [] ] }
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cgj5is
Why are laptop screens so hard to clean compared to smartphone screens? They seem to use some sort of coating that leaves nearly impossible to clean stains where as on a phone they just wipe off, why is that?
Technology
explainlikeimfive
{ "a_id": [ "eui2dfe", "euhx6hv" ], "text": [ "Touchscreens usually have an oleophobic coating on the surface. Phone screens are designed specifically for touch input interaction. Smartphones and laptops with touchscreens have an oleophobic coating on the glass which repels oils and allows for easier cleaning. This oleophobic coating can, of course, wear off over time, meaning finger oils will become progressively more difficult to keep off the screen as the phone ages. I've also seen some devices where the oleophobic coating wasn't applied evenly, and you could tell where finger oils stuck more visibly around the edges of the screen.", "It’s actually the other way around. Touch screens have an oleophobic coating to resist the oil from your fingers from bonding with it, which makes fingerprints easier to wipe off. Laptops usually don’t have this. More info: URL_0" ], "score": [ 74, 3 ], "text_urls": [ [], [ "https://www.phonearena.com/news/Oleophobic-coating--what-it-is-how-to-clean-your-phone-what-to-do-if-the-coating-wears-off_id65974" ] ] }
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cgjozl
Can you make a brand new internet, like it would be completely empty with no data, no website no anything?
Technology
explainlikeimfive
{ "a_id": [ "euhvebr", "euhtj9q" ], "text": [ "You certainly can. And in fact this is exactly what happens if you plug some computers into a router but don't connect that router to the public Internet — you just created your own tiny private Internet.", "Yes. And you'll have to keep it from connecting to current internet. Otherwise it'll just be part of the current internet. You'd have to get people to rerun millions of miles of cabling independently of all current connections. Not very cost effective" ], "score": [ 7, 7 ], "text_urls": [ [], [] ] }
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cgl8yw
How was 16-bit music created on different consoles?
I know that classic consoles like the Megadrive and Super Nintendo used different methods for creating music, but I've always been confused about the differences. A lot of my friends also refer to them as MIDI, which I know is incorrect but I'm not exactly sure why. My understanding only goes so far, but I'm deeply interested. I've heard that the Megadrive used a chip to synthesize music on the fly, while the SNES used samples? I'm not sure what the difference is, and what the benefits or drawbacks are. Please explain for a technical dumdum as myself? ❤️
Technology
explainlikeimfive
{ "a_id": [ "eui9k3c" ], "text": [ "For those of us in the United States, the “Megadrive” is what the rest of the world (except South Korea, where it's the “Super Aladdin Boy”) calls Sega's “Genesis” console. Carry on." ], "score": [ 3 ], "text_urls": [ [] ] }
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cgrjwf
What is the academic reasoning behind believing we live in a simulation?
Technology
explainlikeimfive
{ "a_id": [ "euk3hp8", "euk3n30" ], "text": [ "IMHO, (layman here) is that there is not a \"belief\" that we live in a simulation. It is a philosophical position that we cannot rule out by our reasoning that we are not living in a simulation. There is nothing we know of (by observation or reasoning) that contradicts this position. This does not imply belief or support - simply it is something that cannot be ruled out.", "In short, there are 3 possibilities: 1: humanity (or any other species for that matter) never decides to run simulations of reality because either they decide it’s too cruel or we never achieve the computing power. 2: humanity or other does run simulations but we are the real ones. In this situation the world we live in is the one that in the future will run simulations of reality and thus we still live in reality. 3: we are living in a simulation run by humanity or other The idea is that when these simulations are run, there will be lots of simulations run and the ‘realities’ within these simulations will also run simulations, and then those realities will run simulations etc etc. This means that if simulations are run then there will soon become millions if not billions of different simulations. So if we go back to our 3 possibilities the first possibility is still possible, simulations of reality require huge computing power we don’t have yet and may never have. The second possibility requires that we live in the one real ‘reality’ out of millions of simulations, this means that this possibility is incredibly unlikely. This leaves the last possibility which is that we live in a simulation." ], "score": [ 15, 4 ], "text_urls": [ [], [] ] }
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cgs5gp
How does fiber-optic internet work?
Technology
explainlikeimfive
{ "a_id": [ "eukc3u0" ], "text": [ "We are next door neighbours and I have a red laser pointer. Whenever I bake cookies I want to invite you over to eat them. So I shine the red laser pointer at your house. You have a blue laser pointer. If you are busy and can’t come over to eat the bookies, you can shine the blue laser pointer and I will know to save cookies for you. Fibre-optic Internet is like that, we shine lights at each other through glass cables. We can tell each other many things by shining lights into the cables. We can tell each other what’s the weather like, recipes for good cookies, watch YouTube videos and so on." ], "score": [ 12 ], "text_urls": [ [] ] }
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cgtpnq
How does the open refrigerator at the store with cheese, butter, etc. not spoil the food, but our refrigerators at home need to be closed?
Technology
explainlikeimfive
{ "a_id": [ "euky77f", "eukxm8l", "eukxvi4", "eulcfl4", "eumed7c" ], "text": [ "Fluid dynamics! The refrigerators at a store rely on something called \"laminar flow.\" There are fans at the top of the fridge that blow air along a straight path where all particles are moving in straight lines (\"laminar flow\", as opposed to \"turbulent flow\" where all the particles are moving in different directions). This creates an effective curtain of air that pushes warmer air out of the way, creating an invisible door made out of air. It's not as good as a real door, of course, but it's more than good enough for a dairy case.", "The refrigerator in the store has a substantial airflow that forms a \"door like\" region, trapping cold air close to the food. This consumes much, much more electricity, so you can't have something like this in your house. Even stores are moving towards physical doors when remodeling to reduce energy use.", "In addition to what's been posted, most cheeses and butter are safe at room temperature so they don't need to be refrigerated to the temperatures you would have in your home fridge.", "Also- different foods are more or less likely to spoil. At my store milk is in a cooler with a door. But yogurt and cheese and butter are in an open cooler.", "It's also only used for stuff that is somewhat shelf-stable. Cheese and butter have always been a way of storing dairy beyond its expiration, especially before pasteurization was around. & #x200B; There is actually a lot of tech and nuance that goes into things like grocery stores. The supply chains for some of them are just ridiculous." ], "score": [ 30, 9, 5, 3, 3 ], "text_urls": [ [], [], [], [], [] ] }
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cgy25n
Why do speakers get blown out when you play them too loud?
Technology
explainlikeimfive
{ "a_id": [ "eume0kp", "eunxz5c" ], "text": [ "The voice coil in a speaker is an electromagnet, it vibrates back and forth against a permenant magnet. The voice coil can overheat due to too much power being sent to it. Or damage from moving too far forward/back.", "Beside the coil burnout discussed here, cheap consumer and bad home build enclosures mess with the throw and can damage the cone, tear it up or bang the coil. I have a book on building speaker enclosures, it used to be popular and some still do it for custom car builds and at home. Cheaper speakers can let the cone overextend, tearing it, or bang the voice coil and change the response because of the change in shape." ], "score": [ 4, 3 ], "text_urls": [ [], [] ] }
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ch2reh
What is code and why is a lot of it in 0’s and 1’s?
Technology
explainlikeimfive
{ "a_id": [ "euoclns", "euoam0e", "euoadhi" ], "text": [ "This is a really complicated question, but I'll try to answer it as briefly as I can. Your computer is very much a kind of electrical machine, that manipulates the voltages of different wires, and is designed to preform calculations on those voltages. Scientists realized pretty early on in computer science, that a simple cost effective way to build computers was to use only two different voltage levels to represent different values, a high level and a low level. With just two voltages, you can represent numbers by encoding them into a number system called binary. In binary, we use the number 0 to represent a low voltage and 1 to represent a high voltage. With just one digit you can only have two numbers 0 and 1, but if you have more digits then you can have bigger numbers. In binary 0, 1, 2, 3, 4, 5, 6, 7... gets converted to 0, 1, 10 (we added another digit for 2 because we ran out), 11, 100, 101, 110, 111... Once you can represent numbers in a computer, you can store other kinds of data by mapping the numbers to a code. For example if you want to represent the alphabet, you could make 0 a space, 1 the letter a, 2 the letter b, and so on. It's a code because the numbers represent something else, like letters. You can also represent computer instructions in a code (called machine code) and then you can design chips that read that code and execute those instructions. A chip that does this is called a processor, and the instructions it runs is called a program. You can also represent letters, and this kind of code is called an encoding. ASCII and ANSI are some simple encodings that you can use for English, and UNICODE is an encoding you can use for any language. You can also write letter codes that convert to machine code. This kind of code is called an assembly language, and a computer program that converts assembly to a new program is called an assembler. You can also write more complicated codes that you can use to create programs. This kind of code is called a programming language, and there are thousands of different programming languages with different levels of complexity. If someone says they are a coder, they probably mean that they write computer programs in a programing language. & #x200B; The 0's and 1's in the machine, by themselves are totally meaningless, and it's the machines ability to read those numbers as machine code, process those numbers with computer programs, or to convert them to a different format with encodings that make them useful. The computer can also just read them as binary numbers if it needs to, but binary is still a 'code' of sorts (called a number system) that converts those high and low voltages into numbers.", "Zeros and ones are actually binary code and represent an on or off electric pulse, yet computer languages like Python3 or C++ aren't written in binary but in a human \"readable\" / \"writeable\" language. A little much to explain it like you're five. Pretty complex. That's why grade school kids usually start with something simple like scratch.", "Code simply means \"language\". There are countless computer languages. 0s and 1s are what's known as \"binary\". That's the most basic language there is. Yes or No. On or Off. Simpler than your DNA which is made up of A, T, G, and C. Another way to look at it: computer languages are like atoms. They come in all shapes and sizes. They make the things around us. But they're not the smallest things there are. In an atom, protons and neutrons are made up of quarks. There's an up quark and a down quark. Much as there is a 0 and a 1. All computer codes can be simplified or broken down into the most basic state of binary." ], "score": [ 11, 5, 4 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
ch3i76
Why do Composite signals look so good on CRT's but utterly horrible on modern LCD's of the same size?
Technology
explainlikeimfive
{ "a_id": [ "euon7h5" ], "text": [ "Because w/o having pixels, a CRT display isn't able to produce images as sharp as the ones shown by the LCD. The CRT smoothes the image and hides out some of the image defects, if there are. The pixels you can notice by looking closely to a CRT are just a regular pattern on the screen mask between the screen and the three electron guns." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
ch3mf4
How do just a few satellites give the precise location of a million of connected devices at the same time?
Technology
explainlikeimfive
{ "a_id": [ "euonpzm", "euotxfu", "euoofav", "eups0vr" ], "text": [ "Each GPS satellite just broadcasts where they are, and what time their clock says. That signal can be picked up by any number of devices that have line of sight to the satellite. The devices can then determine their position by trigonometry. Radio waves travel at a constant speed, so if you pick up a signal, and you know when the signal was transmitted, and what time it is now, you can determine the distance to the transmitter. With multiple signals from known locations, you can determine your own position.", "They don't. The satellites just know when and where they are and broadcast that information to everyone who will listen and your gps device uses that broadcast to figure out where it is itself. Think of it like a lighthouse beacon telling ships at sea where they are. The lighthouse has no idea where the ships are and isn't really aware of the ships, but the ships can see the lighthouse fire and figure from that where they are (near the lighthouse). GPS is not two way communication. It is just satellites telling everyone who will listen about their location in space and time and the listeners comparing the signals from several satellites and doing some math to pinpoint their own location.", "The devices aren't really connected, they are just listening. The GPS satellite is constantly yelling toward the ground the same thing: where it is and what time it is. The devices on the ground listen to several of them and triangulate their position by understanding the delay of each signal relative to the other signals, in relationship to the stated position of each signal.", "There’s an internal log of the orbits of each satellite called an almanac that tells a GPS where the satellite is supposed to be at any time. Each satellite sends a time stamped signal that all GPSs with direct line of site (usually excluding the first 6 degrees or so above the horizon) receive. By comparing the time taken for the signal to be read from each satellite you can, this is for visualisation purposes, draw a sphere round the position of each satellite at the appropriate diameter, calculated by timedxspeed of light and where they all meet is your position. Satellites aren’t always precisely where the almanac says they should be so where you should theoretically only need 3, as in radio triangulation, you generally need 5+ to get a decently corrected position. :bonus: you usually exclude anything below about 6 degrees to eliminate too much delay due to atmospheric interference or refraction of the EM signal carrying the time stamp which screws up the math as the ratio of air to vacuum changes the speed of light enough to give a false resolution." ], "score": [ 10, 8, 3, 3 ], "text_urls": [ [], [], [], [] ] }
[ "url" ]
[ "url" ]
ch44x3
How does this image have lines from the TV on it that change depending on zoom?
This image is taken of a screen playing GTA V, and I realize that effect shows up when someone takes a picture of a screen, but I don't know what they actually are or why they change depending on how zoomed in I am. Here is the image. URL_0
Technology
explainlikeimfive
{ "a_id": [ "eup22b5" ], "text": [ "It is called a [\"Moire pattern\"]( URL_0 ) and it happens when two regular patterns don't sync up leading to patches of interference. This is very common when taking pictures of digital displays as the pixel grid of the display is unlikely to match up with the pixel grid of the image capture device." ], "score": [ 5 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Moir%C3%A9_pattern" ] ] }
[ "url" ]
[ "url" ]
ch5k3b
how do ads load on bad service but normal content doesn’t?
Technology
explainlikeimfive
{ "a_id": [ "euplngk" ], "text": [ "Youtube (through Google) have many, many servers across multiple regions of the world to store their data. Very popular content may be hosted on multiple servers to constantly have it closer to the viewer, and on faster servers. Less popular, more normal content will not necessarily be copied on multiple servers, or stored on very fast servers, making the video load more slowly. Ads, on the other hand, will be stored in servers geographically close to you, and fast enough to always let them play as smoothly as possible." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
ch5tzd
How do those Heart Rate Monitors on phones that don't have built in sensors work by using only flash and the camera?
Technology
explainlikeimfive
{ "a_id": [ "eupomzv", "eupotfc" ], "text": [ "The flash lights up your finger, the camera detects any changes to how brightly lit your finger is. During a beat there’s a little more blood in the vessels of the finger, so it blocks a little more light. The camera can see these small variations in brightness. Wristwatches with pulse meters do the same thing, just with more specialised LEDs and light sensors.", "you have blood vessels in the finger that pulse ever so slightly, you put the camera over the finger and the app measures any small change in the light as the pulse will slightly elevate the finger from the camera and thus more light will be visible to the sensor." ], "score": [ 24, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
ch8ska
Why does a 1080p Nintendo Switch look great on a 4k TV, but a game in 1080p on a 4k computer monitor look so pixelated and bad?
Technology
explainlikeimfive
{ "a_id": [ "euqjy8g" ], "text": [ "As people have said, distance, but there is another factor. 4K computer monitors are really only designed to display a 4K signal well. When you send a lower resolution signal, they use very basic techniques to upscale the image and this looks bad. 4K tv's on the other hand are actively designed to be able to display a 4K, 1080P, 720P and even lower resolution signals. This is done through dedicated signal processing chips running advanced upscaling algorithms. (Cheap tv's often save money by using cheap chips which do this poorly.)" ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
cheuo7
Why can’t phones and computers charge almost instantly when you plug them in, instead taking 2-3 hours?
Technology
explainlikeimfive
{ "a_id": [ "eusdhop" ], "text": [ "Electricity is stored in batteries as chemicals held in two different containers separated by a filter-y thing. Letting electrons flow from one to the other through your phone (for example) is how it discharges. Forcing the chemical reaction to go backwards is how it recharges, by way of a smaller circuit connected to the charger. If the reaction goes too fast, it catches fire. This is annoying, and so coming up with a clever (and cheap) solution is an ongoing challenge in electrochemical engineering." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
chgnm5
Why does WiFi in a house or office still suck in an age where we can have a drone transmit a WiFi HD video signal from a mile away?
Technology
explainlikeimfive
{ "a_id": [ "eusz3f7" ], "text": [ "I wouldn't say WiFi really sucks. It all depends on the setup you have: if you have a sufficient number of access points (antennas), or if the ones you have are strong enough. Your house plays a big role in this as well, thicker walls means a bigger loss in signal strength. There's two frequencies used right for WiFi, 2.4 GHz (slow but penetrates walls better) and 5 GHz (fast but bad wall penetration). All this to say if you have a decent router (not the one your ISP sends you) and you place it at the right spot, you'll be just fine. Maybe add a few repeaters or install a mesh network if you have a bigger house. For drones, it's simply because usually they're transmitting in open space (outside) and have only one connexion. It's using a different type of transmission which is more suitable for distances bigger than the size of a home." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
chhfvo
Why shouldn't I mix old and new batteries or batteries of different types (disposables with rechargeables)?
Technology
explainlikeimfive
{ "a_id": [ "eut6g6y", "eutp1v3", "euu4j9s", "euuq8zv", "euuy6r5" ], "text": [ "Different batteries have different voltages. And you don't want to try recharging a non-rechargeable cell. Rechargable batteries generally have a voltage of 1.2 volts, compared to heavy duty or alkaline cells with 1.5. If you were to put a rechargable battery in parralell with an alkaline cell, the alkaline cell would discharge through the rechargable one, overcharging, overheating it and probably damaging it. Batteries also have different capacities - so putting a cheap heavy duty in series with a fresh alkaline or rechargeable cell, or a partialy discharged cell with a fresh one, when the low capacity cell discharges the cells that still had capacity would force charge through the dead cell, charging it backwards. This will cause the discharged cell to leak.", "Til you shouldn't mix batteries. What am I supposed to do when my remote dies but I only have 1 new AA battery left!?", "So batteries are full of electricity that they want to give to the thing you put the batteries in. Electricity moves through metal but it only moves in a circuit, a continuous loop. That's why there is a little bit of metal on both ends of where you put a battery in. The battery is metal all the way through so the electricity can come out one end, go all the way through the device (Which makes the device go!), and then come back into the battery at the other end. However, we lose a little bit of electricity when it goes around the circuit. Some of it kind of, rubs off, wears out. Like tires on a car, or your shoes when you've have them for a long time. Batteries run out too, because their charge of electricity wears out. & #x200B; Now when there's one battery putting electricity into a circuit, it just goes and goes until it gets worn out. But batteries can be different, and there can be problems when you mix them together. Some batteries are stronger- they put out more electricity, than other ones. They have a higher \"voltage\". When you use more than one battery, they all have to be part of the circuit that the electricity goes through. So the electricity goes through all of the batteries and then through the device. But if one battery is stronger than another battery, it will push its electricity too fast for the weaker battery to keep up with. The weaker battery won't be able to push its electricity out faster than its coming in. It will fill up with too much electricity and break. A few different things can happen when a battery breaks, it could get too hot and melt the parts around it, or it could break open and get bad burning liquid everywhere. This might hurt the device or even you. Even with the same kind of batteries, they can get weaker or stronger based on how worn out they are. So you can have the same problem if use multiple batteries from the exact same box, but one has been used for a long time already, and one has never been used before. The older worn out one might not be able to keep up with the new one, and it can break. So this is why it's recommended to use only all new batteries that are all the same when you need to switch out old ones. So they'll all be just as strong and fresh as each other, and can all work together on the same circuit.", "If you think two batteries being two people in one large hamster wheel. The runners have energy and they run to turn the wheel. & #x200B; The most effective way would be for both runners to have the same speed and same stamina. They will turn the wheel at the same speed and tire together. If both runners can run at the same speed, but one has been running for ages and is tired, the fit runner will be limited by the tired runner and could injure the tired runner. In this case, one battery has energy but the other doesn't, the one with more energy will discharge to the one with less, possibly causing damage to one or both batteries. The comedy picture is the slower runner falling down and spinning round with the wheel, whilst the fitter runner works really hard to power the wheel and move the tired runner round and round. He's not running efficiently now, and will tire quickly, possibly overheat from the exhaustion. & #x200B; The same happens when you have one runner who is a lot faster than the other. The faster runner is trying to force the wheel up to his speed but the slower one is slowing him down, even if both have loads of stamina. Again, this can deplete the energy of both runners quickly and possibly cause damage.", "People here are giving really bad answers / entirely wrong answers. Batteries develop internal resistance over time. A battery that is nearly dead has a lot of internal resistance due to the chemicals not wanting to freely give up electrons as easily. Imagine you’re an electron running on smooth pavement. Boom. You suddenly hit a different material like sand or water. You’re going to use up a lot of energy to go through that material and in the process generate a lot of heat / get sweatier. Batteries have thermal limits. Exceeding the thermal limit may cause batteries to leak / explode / generate hydrogen (highly flammable) / short circuit. You want to keep the batteries nearly identical so you don’t have that sudden change in flow. - > An electric heater / stove works on the same principle. You have really fast moving electrons suddenly trying to flow through heavy resistance. The byproduct is heat. So an electric heater / stove is essentially an electron resistance machine." ], "score": [ 565, 70, 41, 18, 3 ], "text_urls": [ [], [], [], [], [] ] }
[ "url" ]
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chlrq8
With the millions (or billions) of barcodes in the world and more being added daily, how are they all unique?
Technology
explainlikeimfive
{ "a_id": [ "euurrxv", "euuxkfo", "euuxv8m", "euuzb7p", "euuvjr3", "euuyska", "euv4kf0", "euv7s52", "euv1w8r", "euus3el", "euv7u5h", "euvabl7" ], "text": [ "Barcodes are actually just a font what represent the numbers that are normally printed just below it. The most common type of barcode in North America is the UPC (Universal Product Code) that is owned and managed by GS1. GS1 officially licenses barcodes for products for sale, using a system where the first N numbers of the code represent the manufacturer of the product, and the rest represent the product from the manufacturer. By sticking to this system, and making sure that their barcodes use the correct manufacturer number, they can know they wont be overlapping with another manufacturer. Manufacturers can also pay more to get a shorter manufacturer code, so that they can have more digits left over to have more products.", "Barcodes also don't necessarily have to refer back to any sort of master list, or anything. Many are just used for internal tracking, so they don't NEED to all be unique. For example, one company offers an office furniture tracking system platform (software and hardware). Every one of their customers could all have barcodes/UPCs that start with 0-00000-00001-0 and go up from there, and it wouldn't matter. The code itself doesn't have any information in it. It's just an identifier to a specific item in a database.", "The barcode is just a representation of the number written under. On the bottle in front of me it is a 13 digits number, meaning 10,000,000,000,000 unique barcodes.", "Short answer: They are not. Barcode is just a way to encode data, and what data you encode is up to you. There are some global systems that allow you to identify a country and manufacturer of products though. But even them usually just refer to product type/batch, not every individual product (so for example all bottles of coke from one shift in one plant will get same barcode). & #x200B; PS. For coca cola one batch can be milions of cans. But the batching happens, that's why sometimes the barcodes \"don't scan\" when the new batch of products come into a store. Sometimes there's a promotion, that would get a new barcode. Often different retailers (big ones like Target, Wallmart), will get their own barcode for a given product. Different sizes of items will obviously also get different barcodes.", "[short talk on barcodes]( URL_0 ) if you're interested in how they work", "On a side note, did you know that the bar code reader, actually read the blank spaces, rather than the black lines?", "There a really good video that covers barcodes/how they’re used: URL_0", "They’re just numbers represented by lines, just like Braille is numbers and letters represented by dots. Fun story about bar codes. At work our prints/copies are tracked and limited to a certain number per month and are tied to our badges that we scan at the copy machine using a barcode reader. Well, I used an app or website to decode the barcode (and type of barcode) and saw that it was just my employee ID with some leading zeroes. As luck would have it our employee ID is also our phone extension, which has a nice published list we can all access. Obviously I used a barcode generator and created several barcodes using employee IDs for coworkers I don’t really care for. Worked like a charm. I don’t think I’d ever come close to hitting my copy limit before, it was just kinda fun to work it out.", "Fun fact: the lady who invented the barcode or some aspect of it donated $1,000 every single week in the donation basket at my church growing up.", "Barcodes operates as an alphabet, so they don't need to be unique. When you scan it, it just needs to display a item number/name, that a system can read from its stockhold index, and from here you get the price, or any other information needed.", "/u/MrOctantis summed up most of the barcode details nicely, but I just wanted to make it known that each company has it's own set of barcodes. Barcodes are used in the same way that employee identification is used within a business. You could work at Target with an employee number of 201 and then turn around to work at Taco Bell and get the same employee ID number. The same is true with barcodes. Each company has it's own set of barcodes to track the quantity of goods they have sold and have restocked. These barcodes are completely separate from other companies and manufacturers, so overlap and limited availability of barcodes isn't an issue.", "It’s really simple barcodes is basically a language. The spaces between lines and the type of line is all repressing different numbers. The first half of a classic barcode usually is the number of a the company who make the product. So Coca-Cola barcodes will all have the same first half. The second half is the product code. That will be unique so, a Coca Cola cherry can will have a different second half to a Coca Cola cherry 2 litre bottle. Companies can apply to a central barcode organisation to resister themselves and get a new barcode. They also send them new product numbers when they release new things. You can actually learn the barcode language, not that you’d need to as the barcode number is usually printed below. There is a great podcast on it from stuff you should know if you want to know more check it out." ], "score": [ 8307, 781, 167, 39, 29, 17, 11, 11, 4, 3, 3, 3 ], "text_urls": [ [], [], [], [], [ "https://www.youtube.com/watch?v=qT_gwl1drhc" ], [], [ "https://youtu.be/XPuTZMp-HE8" ], [], [], [], [], [] ] }
[ "url" ]
[ "url" ]
chlz9m
Why does using an ad blocker cause the youtuber not to earn ad revenue? How does youtube know that ads are being blocked?
Technology
explainlikeimfive
{ "a_id": [ "euuvb2c" ], "text": [ "I'm not sure which method YouTube uses. But one common method of measuring ad displays is looking at how often an ad image is displayed. When you see an ad on a website, it means the image for that ad has been downloaded to your computer to display it in your browser. This download can be tracked on the server where the ad has been hosted. When you block ads, you prevent the displaying and thus downloading of the ad image. Which means it never gets counted as a displayed ad." ], "score": [ 16 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
chmtkr
Why is it that when we take a picture of the sun or moon with our phones it never really looks like we see it with our naked eye.
This morning a big beautiful dark red sunrise over the lake. Then i snap a picture and its a blurred red dot.
Technology
explainlikeimfive
{ "a_id": [ "euv867d", "euvb0en" ], "text": [ "Dynamic range. Your eye can resolve a candle a mile away at night, or the sun shining on white walls at noon, basically at the same time. Phone cameras are more limited, and tend to adjust for the brightest object in the field of view. That tends to darken everything else relative to your eyesight.", "The eye is not a camera, not at all. The sense cells in the eye have a combined \"how bright is it\" sense, which is used to control the iris, the eye's aperture. However, each individual sense cell has its own gain sensitivity. The camera in your phone probably doesn't even have a variable aperture. Instead is has an overall gain control that it uses to adapt to overall scene brightness. That leaves bright regions over exposed and dark regions under exposed." ], "score": [ 6, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
chok2v
How private is texting?
Technology
explainlikeimfive
{ "a_id": [ "euw4oud", "euvwtuu" ], "text": [ "If you're in the secrets-keeping business, they are not private at all, and virtually public information. Cell Phone Companies can easily see in plain text who you're texting and what you're saying at any time. It's a relatively open secret that most providers, app developers, and phone manufacturers are at least screening your texts for marketing analytics. Internal controls are the only thing preventing individuals working for a cell phone carrier from reading your texts. Deleting texts does not delete it from your provider's records either. Only from your local phone, and maybe the online texting access point on your provider's website. You should also know that it's relatively trivial for a lawyer working against you to get a subpoena for your FULL text history if they can show a need for it. Divorces, employment disputes and custody fights are pretty great times to start seeing what the other party is saying. Most providers will blindly comply with a lawful court order and not fight it in any way. Even if the messages end up not being relevant to the proceedings at hand, you should assume everyone involved in the trial had a chance to give them all a good read. If you're worried about governments spying on you, [John Oliver]( URL_0 ) had a great piece on it. Generally speaking, it's illegal for the US government to read any messages that stay within the US border. However, since most of our devices are backed up on \"the cloud\" and it's good practice for \"cloud\" providers to have backups outside the country. That means when you sent a picture of your dick to your girlfriend, it was conveniently backed up on Verizon's Cloud that keeps a copy on their French Data Center. Since the message was sent overseas, the US government can now take a look at it because it's \"foreign communication\". Again, I'm not saying that some neckbeard is quietly stroking it to the messages between you and your girlfriend. 99% of people are fucking boring so nobody's looking without cause.", "If anyone malicious really wants to see your texts, they'll see them. Mobile providers and governments cannot be trusted. That being said a service like WhatsApp which uses end-to-end encryption is a lot more private, although there is pressure on them to give governments backdoors." ], "score": [ 6, 3 ], "text_urls": [ [ "https://www.youtube.com/watch?v=XEVlyP4_11M" ], [] ] }
[ "url" ]
[ "url" ]
chpnak
Images contain location data - how does this work? Is this applicable to all image files, including things like screenshots?
Technology
explainlikeimfive
{ "a_id": [ "euw59lx", "euw5k57" ], "text": [ "Image file formats, such as JPEG, contain a special section for textual notes to be attached to the file. Exif is a notable one. URL_0", "The file containing the image doesn't just contain the picture data (colors of each pixel), but can also contain metadata such as location, camera orientation (e. g. portrait vs landscape) and time where the image was taken. It's simply stored in the file, next to the actual image data. Most phones will at least timestamp pictures, and I think geo-tagging them can be turned off. There is software which lets you see what metadata is stored in your images, like the online tool exifinfo. EDIT: and to answer your question, yes, you can totally manipulate it." ], "score": [ 4, 3 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Exif" ], [] ] }
[ "url" ]
[ "url" ]
chprja
How exactly do things like Google home and Alexa work?
Technology
explainlikeimfive
{ "a_id": [ "euw65rp", "euxexjk" ], "text": [ "The machine constantly listens for the trigger word. Once it hears that, it records the next few seconds of sound and sends them over the Internet to a server, for analysis and response.", "I actually know the guy who \"invented\" Alexa. There is a dedicated chip on the device that listens and only rembers one or two words at a time. It forgets everything it's heard just after hearing it. If it hears the word \"Alexa\", it wakes up and starts recording everything that's said for a few second. It can't understand any word other than \"Alexa\" and \"Stop\". So it takes all the raw audio and uploads it to a much bigger computer in \"the cloud\". The bigger cloud computer has a machine learning algorithm that gets trained by people to recognize certain sounds as text words. These text words are then run through a seperate *intent recognition* machine learning algorithm. Which kicks off specific *functions* that exact can execute." ], "score": [ 7, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
chqv2g
Why are some money sharing services such as Venmo able to deposit money into a bank account virtually instantaneously while other services such as PayPal take multiple business days to do the same?
Technology
explainlikeimfive
{ "a_id": [ "euwmlyw", "euwwkzs", "euwr76t" ], "text": [ "Venmo deposited basically by using your debit card in reverse. Those transactions happen nearly instantaneously. The paypal transfers are done through ACH (basically an electronic check) and since those are done in a few daily batches rather than through a card processing network, there's a day or two delay in those being processed and settled.", "Basically, trust. Or varying levels of it. Let's say you're buying a house from me. I don't know you. I have no reason to trust you. It's impractical for you to hand me a briefcase full of $250,000 at the same time I physically hand you the deed. You need to write me a check or some promise that your bank will give me the money soon. I don't want to hand over the deed until I get the money, but you don't want to give me the money until you get the deed. So we're at an impasse. Enter brokers, or escrow services. These are third parties that don't trust either of us. I give them the deed. You give them the money. Once they verify that both sides have done their half of the trade, then they swap them and give them back to us simultaneously. (In a real estate escrow, there's actually more than just two parties involved, like mortgage companies, and it's even more complicated. But same general concept.) Bank to bank transfers like checks or wire transfers typically work the same way through various methods. Checks and electronic transfers go through a mechanism (at least in the US) called an Automated Clearing House, or ACH. Due to long-standing technical limitations, no clear owner, and an unwillingness to invest in new technologies because of it, ACH's still have a 24-72 hour wait period before the transfers complete. Any kind of transfer built on top of ACH will have a similar delay. Credit card companies, however, have other means. They can often act as their own escrow or ACH. They can dispense the money to the target vendor immediately and know they have means of making you pay up later. They temporarily undertake the risk on the vendor's behalf, so they're able to pay out immediately, before waiting to make sure they get your money first. Most debit cards are backed by one of the major credit card companies' payments networks and work the same way, like Visa or Mastercard, which is why they carry their logo. They can dispense the money immediately, knowing they can make your bank pay up later. But in order to do this they charge a fee, and a lot of companies don't want to pay it, so they instead fall back to using ACH transfers, which are basically free but take longer. Venmo is built on top of the debit card and credit card network. PayPal transfers are (usually) built on top of ACH. It's all about who you trust, what kind of deals you've cut, and how much you're willing to pay in fees to use it.", "PayPal owns Venmo. Doesn’t answer your question but thought it was interesting you used those 2 apps as examples." ], "score": [ 12, 6, 5 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
chs1yn
How do solar panels work?
Technology
explainlikeimfive
{ "a_id": [ "eux2uko", "eux21o7" ], "text": [ "Solar panels are two layers of semiconductors, one laced with a substance with fewer electrons (+) and one laced with a substance with more electrons (-). When light passes through the layers, it knocks an electron lose, causing it to jump up from the negative side to the positive side, and another electron from the wire jumps in to fill the gap. It takes energy to force the electrons to go the opposite way, however, meaning that the easiest route for the newly freed electron is through the wire. Interestingly, LED bulbs are the exact same thing, only you force electricity to go through it the other way and it glows. You can even make solar panels glow this way, although it tends to damage them. And, unfortunately, that glow is in the Near-IR spectrum, so it's invisible to the naked eye, but some common cameras can see it anyway.", "The 'face' of a solar panel is composed of many tiny photovoltaic cells (which are BASICALLY tiny silicone filters that separate the photons (light particles) of the sunlight). There's 2 layers of this sheet of cells, the top layer has phosphorous added to it to increase the amount of electrons, which gives a positive type charge to that layer, the bottom layer gets boron, which reduces the electrons and creates a negative charge, so this creates an electric field between the 2 layers due to magnetism, and when a photon of light hits that solar panel, it pushes electrons out of that field and thus creates a limitless source of power as long as it has sunlight. Pretty ingenious invention. Sorry, kinda hard to actually r/explainlikeimfive x)." ], "score": [ 5, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
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chtt6p
what is data mining?
Technology
explainlikeimfive
{ "a_id": [ "euxpx4d", "euxrwno" ], "text": [ "I can think of three possible interpretations for your question: 1. People trying to figure out the details of software, especially games. 2. People trying to find trends or details in statistics. 3. \"Mining\" cryptocurrencies. ___ Assuming the first one, \"data mining\" means finding out hidden or unreleased information that is not visible to normal users. It is a hobby for some people. For example, someone might \"data-mine\" the actual odds the computer is using when it \"rolls the dice\" to give out a random prize. Or they may reveal a new quest that players can't start yet, by finding where the dialogue between characters is stored. ____ The second interpretation involves getting a lot of data -- like sales and staffing for a company -- and trying to look for something interesting and useful to the company. Finding those interesting trends and results is typically a paid job. ___ The last unlikely option, with crypto-currencies like Bitcoin, is much harder to explain. In short, it means tasking a computer with a hard somewhat-pointless puzzle to prove that you did it, to get internet-points.", "Usually data mining is a thing coming with large quantity of data. When you do real statistics you postulate a thesis that you prove or disprove, but when you have lots of data you can use certain techniques to find patterns and correlations that hint at things being connected. A lot of market analysis is based on that. Users generate huge quantities of data on websites which google or some other service collects. But that data is way too much to be looked at by people, so they use algorithms to sift and sort through that data and finding connections, figuring out from your user data what kind of book you would enjoy next or how long your current relation ship might last. It is very complex and long winded process with less than perfect results, that is why it is called mining, you have to do a lot of digging to find a nugget somewhere." ], "score": [ 7, 4 ], "text_urls": [ [], [] ] }
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chu7jm
How is television broadcast
This one is for my mum, who has almost zero understanding of how technology works, But she dosn't understand how a thing can be recorded, sent by an antenna, and then turned into a picture on the end. Thanks in advance all!
Technology
explainlikeimfive
{ "a_id": [ "euxzxzc" ], "text": [ "Disclaimer, im not an TV expert by any means so someone else may be able to correct me on some places, but i believe this is how things work in a nutshell The signal is like using Morse code at a fixed frequency, or if we want to use sound, a pitch. Let say we can only hear 1 pitch, how can we speak to each other? well, along that pitch, we can use a simple \"yes sound/no sound\" by alternating the pitch and silence, we can communicate thorough Morse code.If another person enters the conversation, we would have them use a different pitch, so if i was communicating in E, we can get a second person to communicage in G, and you can switch between the two pitches to focus on each source. This is what different channels do, they pick a different frequency, and you can tell your TV which frequency to listen to. The only difference between morse code and tv signals are by using 2 different intensities (loud, soft) to represent 1's and 0's for the TV. To ensure your TV is replaying things correctly, the information from the source is broken up in section, which match the frame rate of the TV. Your TV listens for the start of each packet, then the information for each row of pixels on your TV, then it gets the audio for the TV and whatever other information after." ], "score": [ 3 ], "text_urls": [ [] ] }
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chyurq
How do game/movie studios store and archive projects?
Like, say a game is no longer being made for some reason. I assume they archive it in some way for future reference and just to have a master copy of a project. Is it as simple as a .zip file on a server somewhere?
Technology
explainlikeimfive
{ "a_id": [ "euzoeu8", "euzqmij" ], "text": [ "The best information we have is from games that have been discontinued and then years later there is a project to restore the development of the game or movie in order to make a new release. And the archiving process varies wildly between companies and projects. You should think that it is enough just to make a zip file of all your source files and write it to a tape. However there is still a lot of external dependencies like compilers, libraries, tools and such. So even with the source files you may not have the same versions of the external dependencies and it would take a bit of work to be able to start development again. We even have studios archiving different versions of different source files so they do not actually work together without modifications. Digital archeology can be frustrating.", "It depends on the company and its policies. > Is it as simple as a .zip file on a server somewhere? Perhaps, especially for older titles. For modern software, almost always a Git (or other version control) repository is used, which keeps a history of changes during development, allows many simultaneous changes to be made independent of each other, and keeps track of releases. There is usually a central server where the master repository lives, either on a physical server (likely many servers) on company property, hosted by a hosting provider like AWS, or on a dedicated cloud service like GitHub. When the project is discontinued, the repository might be set to read-only, allowing the code to be seen but not changed." ], "score": [ 5, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
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ci1din
What is that "blurry effect" seen in photographs when an object like a car or a train moves quickly?
Technology
explainlikeimfive
{ "a_id": [ "ev0hjr3" ], "text": [ "There are many multiple things but the simplest way to explain it would be with exposure time. That's the time the film or light sensors collect light. Since most cameras are digital lets stick to to that. So for however long the exposure time is the sensors collect the information that will determine the color of the pixel. But if something moves quickly then multiple different colors will be collected and in that way cause the blur. & #x200B; That's the simplest way to explain it. Then there is things like focus and more complex parts which I'm not as good in so at its basic think of it that the pixels on the photo are open and collecting light for a brief moment and if there is too much movement they will capture several different points of data instead of what you were expecting." ], "score": [ 5 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
ci4lq6
Why do downloads in some websites start "in a couple of seconds"?
Technology
explainlikeimfive
{ "a_id": [ "ev1e1j2", "ev1dtz8" ], "text": [ "Usually it's so they can control the flow of traffic to and from their server so the site doesn't crash from too many connections at the same time.", "Generally landing pages like that either have some other kind of information on them, or they have ads on them. Impressions on the ads matter for these sites for their revenue." ], "score": [ 4, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
ci68e7
How do people like firefighters/exterminators determine the “origin” of a fire/infestation?
Technology
explainlikeimfive
{ "a_id": [ "ev24kfo" ], "text": [ "Firefighter since 2008 here. Most places don't burn to the ground with nothing but ashes left. Finding the origin consists of viewing how far along things burn and understanding a fires normal path. Fire burns up and out, with a goal of getting more air to feed itself. In this way there is often a V where the about lowest point in the fire damage has some of the most thorough burning done to it is the likely spot where a fire had started. Then you look at what was in that area that may have been able to start a fire, like a candle, or a hair straightener, or electrical wiring, space heater, etc. That's the simplified version of how it's done. Many get more complicated than this, but that and some experience in looking at fires is the normal method of finding the origin most of the time." ], "score": [ 12 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
ci8ih7
Why are there so many different internet browser and can I make my own?
Technology
explainlikeimfive
{ "a_id": [ "ev2fdee", "ev2g0tg", "ev2siml" ], "text": [ "So, there are two different aspects of an internet browser: the user interface and general usage, and the browser \"engine\" which does the transforming of a webpage to a more computer friendly structure. There are only 3 main engines now: gecko (firefox), blink (chrome, brave, opera, modern edge, etc., and which is based on webkit) and webkit (safari). You could make your own browser using an existing engine which would take some work, but the biggest codebase is the engine. Making your own engine would take in all likelihood a number of years.", "Yes, you could absolutely make your own. It would be a lot of work, but anyone could make one. When it comes to software, the answer to \"Could I make my own < piece of software > ?\" the answer is generally yes, but it might take a while to learn how, and a while longer to actually do it.", "Absolutely yes. However do keep in mind these companies that make chrome, safari, even edge and IE, have large teams of very knowledgeable and experienced people making these. Odds you best them alone are pretty much 0 (unless you're some crazy genius!) Just based on sheer time availability and man hours. If you're just looking to use an engine and make a pretty ui, sure go for it" ], "score": [ 16, 12, 3 ], "text_urls": [ [], [], [] ] }
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cie1zo
FAT32, exFAT, and NTFS: what’s the difference, why does it matter, and why does the size of the drive limit formatting choices?
I had a great idea to buy a 256 gb usb drive (that’s bigger than my bare bones computer’s internal storage!). I put all my tv shows and movies and music on it so excited to just plug it into my tv and enjoy. And then the formatting wars started and I’m so confused. Somebody shine a light on me.
Technology
explainlikeimfive
{ "a_id": [ "ev49959" ], "text": [ "Tl;Dr: they are the same but allow slightly different maximum sizes for hard drive partitions. Full spiel: all memory is kept in paired bits of hexadecimal code. This code is the arranged into a grid, or table. A part of this table is the address table/lookup table (there are a few other names for this table too). This table is usually kept at the very beginning of the entire partition (section of hard drive), and sometimes at the end too. FAT32 - FAT stands for file allocation table (remember the address table?), the 32 simple means that data is stored in 32 bit chunks. This is the most common by today's standards and FAT was developed originally for Windows systems, but is in common use in many, many systems today. Files are allowed to be a max of 4gb in size and smaller files have a minimum size (called cluster size in FAT) of about 16kb. The maximum partition size of FAT32 is 8gb. NTFS - NT files system is Windows newer default system for memory allocation. It supports security permissions (file permissions, read and write or write protection), change journals (records of actions performed), shadow backups, encryption, quota limits and a few other things I will gloss over. There is no file size limit and no partition limit (at least not realistic ones). Where this file system lacks is in compatibility, very few systems other than windows can read and write to NTFS drives. Xbox one can, but earlier Xbox models cannot, PlayStations cannot, macs cannot; with Linux your mileage may vary. ExFAT - extend FAT is another Windows designed system, it is build with size in mind. As with NTFS, it has large limits on its file and partition sizes. ExFAT is much more compatible than NTFS, macs offer read and wrote support, many Linux systems have add ons to read and write to it. It's only really big disadvantage is a lack of support for journaling, or logging changes to the state of the drive. All told, this is probably *my* preferred format, for now." ], "score": [ 9 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
cif01p
how does hacking work?
Technology
explainlikeimfive
{ "a_id": [ "ev4oh3t", "ev4rx2k" ], "text": [ "It depends what you mean by hacking. But there are various ways that someone can do it. For example, it's very easy to send an email which appears to come from, well, whoever you want. So I could send you (and millions of other people, cos I buy a list of email addresses) an email which appears to come from Amazon, saying that there's a problem with your account and you need to click < this > link to login and reset your password. Only the link doesn't lead to the real Amazon website, but to a fake copy of their login page that I made. So when you log in, you've now typed your password into a web page that I control. I now have your Amazon password, so I can log into the real site, change your shipping address, and buy stuff. This fake-website thing is called phishing. Here's another method. Imagine you're Amazon (the real one this time). The first page of your website asks people to log in, so they type their username and password into the boxes. Let's say you type in uuu and ppp. To find out whether those details are correct, the web site checks its database of usernames and passwords. The basic logic of the database query would be \"count all the entries where the username is uuu and the password is ppp\". If the number of matches is precisely 1, then the system knows who you are, and regards you as having logged in. Now, imagine that, instead of typing in ppp as your password, you type \"ppp, or 2+2=4\". As before, Amazon takes the username and password from the boxes you typed, passes those values to the database, and uses them to complete a query. The query now looks like \"count all the entries where the username is uuu and the password is ppp, or 2+2=4\". And you know what? Even if the username and password are wrong, the number of matches is 1, because 2 + 2 does indeed equal 4. So the system regards you as having successfully logged in! This is called a database injection attack, because you're injecting new commands into the database query. It's why you're not allowed to include \"+\" symbols in your passwords. (OK so it's a bit more complex than that, but this is ELI5. You get the idea.) Now, imagine what happens if, as the password, someone types \"ppp, and please show me the database of usernames and passwords\". Yup, the hacker now has the whole database. Just because the programmer who wrote the login system didn't understand something called input sanitization, which means checking that people don't include valid database commands as part of their username or password.", "it works by studying the system and identifying weak points, then find a scheme where you exploit the weak points for your goal. Say i would phone your grandmother, convince her i'm you, and arrange circumstances that let her pay for something she would do for you, say new sneakers. i would exploit the weak points of elderly people who don't hear that well, usually don't know their grandchildren well, have bad memory which they know, get surprised and excited easily when called, feel social pressure to help family, and may have money laying around they don't know what to do with it. That would be basically \"hacking your family\"." ], "score": [ 14, 5 ], "text_urls": [ [], [] ] }
[ "url" ]
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cii1du
why a BIOS update is so much slower than copying a 16MB file
.
Technology
explainlikeimfive
{ "a_id": [ "ev5xilg" ], "text": [ "The bios isn't just stored on disk. It's stored in a special kind of memory that retains its data even when the power goes off. This memory requires special instructions to update, and it's usually updated one word at a time, rather than in blocks via direct memory controllers. Since the operation isn't \"undo\"able, there is a lot of checking that you have the right data and all the data is ready before the operation starts." ], "score": [ 13 ], "text_urls": [ [] ] }
[ "url" ]
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cii85f
why is the color green the only one that is used to edit backgrounds/things in movies? Why can't other colors be used?
Technology
explainlikeimfive
{ "a_id": [ "ev5ud2h", "ev5tcn4", "ev6547r", "ev5teg3", "ev5teck", "ev6l1ap" ], "text": [ "When more movies were shot on film, they used to use blue more commonly. This process is called \"keying\" and it involved a chemical treatment to the film to remove that specific color. The green you see today is called \"Digi Green\", and it's color matched to the small green filters inside camera sensors to give as clear and vibrant of a green as possible to aid in the digital removal of that green. But depending on the real elements in the scene, they may use Digi Blue, or the older colors called Chroma Blue and Chroma Green - which were color matched to the color filters in the film emulsion. Today, since all these effects are digital, you can also \" key \" out by any color, a range of color, or even by brightness.", "Green and blue are both used. Generally they want to use colors that don't show up that often in nature/clothing so that the programs they use to insert digital effects only place those effects where they are wanted.", "Here is an excellent video made by a video expert on the subject, it’s really simple to understand but is really precise at the same time URL_0", "Other colours can be - and are - used sometimes. The shade of green on a green screen is chosen because it's easier to remove completely from a shot and replaced with an alternate image. If they used a more commonly occurring colour - say, blue for example, there's a chance the colour is present in clothing or skin tones or other prop devices. By using a colour that isn't present elsewhere they avoid the unintended deletion of other items when the green is removed.", "It's not. They use blue screens. \"Green is the go-to because it doesn't match any natural skin tone or hair color, meaning no part of an actor will be edited out through chroma key. When a green costume or prop is essential, a blue screen is often substituted.\" -google", "ANY color can be used, but they don't just edit the background out, they edit out anything in that or a similar color. Thus, they need to use a color not likely to show up anywhere else in the scene and that shade of green is pretty rarely used, so it's the chosen color a lot. Sometime, hillariously, someone happens to wear a shirt to close to the background color and they become see through. Happens on yourtube and twitch quite a lot as the people aren't always so careful to check the colors of their clothes. See this video for when a meterologist misjudges of colors of her dress. [ URL_0 ]( URL_0 )" ], "score": [ 32, 7, 5, 5, 3, 3 ], "text_urls": [ [], [], [ "https://youtu.be/aO3JgPUJ6iQ" ], [], [], [ "https://www.youtube.com/watch?v=bSWgL9dxW7g" ] ] }
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ciij3i
How does the police obtain the position of a call without the phone having location turned on?
I know this is possible and is also less accurate than GPS positioning, but am not really sure how it works. My guess would be that they get the info from the provider who calculates the position based on the caller's proximity to their antennas. Also, why is it less accurate?
Technology
explainlikeimfive
{ "a_id": [ "ev5xm1h", "ev5yoln" ], "text": [ "They use the signal strength of your phone between multiple phone masts and that helps them narrow bit down. Its also instant you don't need to keep someone on then line", "Every phone pings to it's nearest tower while on call, they'll select 3 towers in shape of triangle , by using mathematical formula they'll find distance between tower and caller device then they'll search in area where tower is near that's why it's not much accurate but we can find device within range of 600m nearby" ], "score": [ 6, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
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cim25i
Why does putting your tongue on a 9V battery hurt, but not when you touch the poles with your fingers?
I have touched tons of batteries throughout my life, like I expect most people have, but I have never received a shock. However, when you put your tongue on the poles of a battery, it gives you an electric shock. Even if I wet my fingers, I can't produce the same effect. Whenever I attempt to get this answered by reading up, it goes very advanced very quickly and I struggle to keep up. Can someone please explain this for me?
Technology
explainlikeimfive
{ "a_id": [ "ev7aifd" ], "text": [ "The saliva on your tongue is a much better conductor than the dead skin cells on your finger; even if you make them wet, dead skin cells. The tongue also has more sense cells per unit area than almost any other part of the body." ], "score": [ 4 ], "text_urls": [ [] ] }
[ "url" ]
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cim8yg
If computers simply take in a given input and give out a specific output, why is it that sometimes something will work or not work if you simply try again?
E.g. I was just watching an embedded video, and when I clicked enlarge, it froze and crashed. But when I refreshed the page and tried it again, the video worked. Why did it crash in the first place, and why did it then work upon retrying, even though theoretically, nothing should have changed between attempt 1 and attempt 2?
Technology
explainlikeimfive
{ "a_id": [ "ev7d89n", "ev7jmkw" ], "text": [ "A lot changed between the first and second attempt. Imagine trying to drink tea and finding out it's too warm. You wait 20 minutes, try again and find out it's now ready to drink. Theoretically, you could say that you did the same thing on try 1 and 2, and yet the result was different. This is because of other processes that go on between the tea and the air that are independent of your actions. Similarly, literally billions of things happen in your computer every second that are independent of you. Some of those might affect the outcome of your actions, even though theoretically they are identical.", "Computers try their best to pretend those two cases are identical. But sometimes they fail. For example, a hard-to-trace bug known as race condition can wreck havoc. In it, two processes are running side by side, and usually A finishes before B, and everything works. However, there are many reasons for why sometimes B might finish before A. Like, CPU chooses which processes to process somewhat randomly. If it just so happens A gets put on queue because some system thing takes up the slot or something, well, now A finishes after B. It's the same code, but because of timings and whatnot, you might end up having it be random which one finishes first. And that then might change how program operates. For example, desktop operating systems work by promising programs a play-pretend world where they are the only program running on that computer. This is a lie, but because of lots of hard work, this play-pretend works most of the time, and you can write programs without having to worry at all what other programs are doing. But in some cases somewhere along the line, these lies get revealed in nasty ways. Like in race condition where other programs might indirectly influence if A or B finishes first. If A and B actually were the only programs, then you'd have same result every time, probably." ], "score": [ 27, 9 ], "text_urls": [ [], [] ] }
[ "url" ]
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cirpdn
How does a solid state drive work, physically and in terms of memory, compared to a hard disk drive, and what happens to both when you delete/overwrite files?
Technology
explainlikeimfive
{ "a_id": [ "ev8s2w0", "ev8zb59" ], "text": [ "Hard disks are composed of spinning disks that can be magnetized or de-magnetized in order to store data. To read or write on a certain part of the disk, the target region of the disk must sit below the read-write head. This part of the disk is then either re-magnetized or measured by a magnetometer. To achieve this, the disk spins, and the head moves closer/farther from the center of the disk. This means that memory access speed is limited by how quickly the disk spins and how quickly the head moves. Solid state systems, meanwhile, store data in special transistors. These transistors are arranged in such a way that a few electrons get trapped inside or outside of a part of them, and these electrons can be detected by the special transistor. These electrons are moved by other transistors in a network that decides which particular bit of the drive is to be read. The speed of these drives, if fully optimized, is primarily limited by how quickly data can be squeezed through the wire and terminals that connect them to the processor/RAM. In reality, (I think) these drives are limited by how quickly they can detect and communicate the presence of this excess/lack of electrons.", "In SSDs, you’re basically storing your bits of data in special transistors called floating gate. Electrons can get trapped in an area and stay there for a long time, even without any power. The SSDs have circuits that detect if there’s any electrons trapped or not in these floating gates. Obviously you need a ton of these transistors to be able to store som descent amount of data." ], "score": [ 67, 6 ], "text_urls": [ [], [] ] }
[ "url" ]
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citpld
Why does using different codecs for an mp4 file often make it incompatible for some software to use (Premiere).
Technology
explainlikeimfive
{ "a_id": [ "ev94pt6" ], "text": [ "Container vs Codec: Every video consists essentially of still images played at a frame rate. Each image consists of pixels. Each pixel consists of 3 colors. Each color takes up a byte at least. This is a lot of data. File sizes for videos would normally be massive if not for a little trick we knew, compression. Compression takes a file and just applies various tricks to shrink its size. For instance if it sees that two frames are the same, rather than storing both, it will store one and have the place where the other one is say \"this is a duplicate of frame x.\" But in practice things get more complicated than that, we have developed a **lot** of math tricks to bring file sizes down. These compression algorithms are known as codecs. Software that would play video that uses them has to have the decoding algorithm for that codec to figure out what the pixel colors and what not are. This differs from a container, which holds the video compressed by the codec, along with a lot of other things, like audio, subtitles, ect. MP4 denotes container, not codec. Its just a way of organization." ], "score": [ 6 ], "text_urls": [ [] ] }
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ciuh16
how do ICBM travel such long distance in short amount of time? Can they be intercepted?
Technology
explainlikeimfive
{ "a_id": [ "ev982fo", "ev9b735", "ev98c3f", "ev9qgtj" ], "text": [ "It's a warhead strapped on a rocket. Rockets go fast. If you can identify and properly track the rocket, sure. You'll need a rocket that can go faster than your enemy's.", "Because an ICBM is a just a rocket and rockets go really fast. Rockets that reach orbit are traveling at least 7.8 km/s. ICBMs are only a little bit short of that speed. The very first rockets that sent satellites and even humans into space were literally ICMBs but with a satellite or capsule instead of a nuclear warhead. Can they be intercepted? Technically yes, but it's really hard even under ideal circumstances. It's like trying to shoot a bullet out of the air with another bullet.", "An ICBM is really just a single state rocket booster with a warhead slapped on top. They can go extremely fast at altitude as a rocket engine that carries its oxidizer with it does not lose thrust with altitude, where the air gets thinner means it can go much faster only being limited by heat friction. And yes they are possible to intercept with other missiles. But it is an untested system. As far as i know there are no aircraft that can get to ICBM altitude and launch an AAM at it before its out of firing range making interception very unlikely.", "An ICBM is a multistage rocket. The first two stages will get the payload up a few thousands kilometers in about 5 minutes, the third stage will then propel it towards its target at a 6-7 km/s letting it arrive anywhere on the world in 30 minutes of launch. This timing may seem really short, but remember the ISS orbits the Earth every 90 minutes and it doesn't have a big rocket strapped to its back to hurry it along. They also go up far enough that the Earth does orbit under them as their orbital circumference is now 50% longer than the Earth's circumference. Once they're headed back in, it will deploy the MIRVs(Multiple Independent Reentry Vehicles) of which some are decoys and some hold nukes that will take out a city. The Sub launched Trident II has 8-14 MIRVs on it. Interception during the Boost phase(initial launch) is easiest from a technical stand point as you've got this big missile that you need to hit and it isn't moving very fast yet. The problem is that they tend to be launched from deep inside a country's territory to protect them while makes this feasibly the hardest stage to intercept them in. The other most likely stage for intercept is the Terminal stage when the reentry vehicle with a warhead or a decoy is headed straight at you. Its moving at Mach 10 towards you so you don't have long to hit it. Its now down to about 0.3 meters in diameter and 1 meter long which makes it a pretty small target, and if you miss millions die. Good luck! There are also efforts to make the MIRV steerable. When you hear concerns about a Hypersonic Reentry Vehicle this is what it refers to. Its hard enough to hit a 0.3 x 1 meter cone that is flying in a perfectly straight line, it will be even harder if it is taking evasive maneuvers on its way in." ], "score": [ 14, 9, 6, 4 ], "text_urls": [ [], [], [], [] ] }
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ciwoas
How do you decide the design and shape of a product especially if it's new? And who decides it?
Technology
explainlikeimfive
{ "a_id": [ "ev9mq7g" ], "text": [ "Most products go through a lot of design steps before they are put into public It usually start with concept artwork, schematics & CAD design then once that is refined a prototype is made Prototypes can be expensive to manufacture so you usually want to limit the quantity & once you have the prototype you can beta test it & tweak the design, aesthetics & materials for better functionality, appearance, ease & cost of manufacturing etc Then you would put it out to tender with manufacturers capable of mass production & get costs - they will usually provide a sample for an agreed cost & then you choose the mass producer you want to manufacture the product If you going to manufacture it yourself you need to factor in the cost of the setup & operation of that into your product & or amortize it over a number of products Essentially who decides what design & materials the product have is up to the individual or company who will be selling it & usually based on consumer feedback during beta testing & focus groups" ], "score": [ 8 ], "text_urls": [ [] ] }
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ciyw69
How do they do a print run for a magazine and know what the right sort of paper is?
Given that my only graphic design experience was learning about Adobe InDesign, this relates more to the *printing process*. [ (I've only ever dealt with graphic design side, so that's probably why). For example, if you had a magazine at 204mm height x 280mm width, that had a glossy cover but paper that wasn't glossy inside, how would a publishing company know what sort of paper's good [that's not newsprint paper]? This isn't about any specific magazine, just printing in general. I've done some basic research but worry it may be out-of-date. I know what a print run is, and about the basics of newspaper presses, but this relates to magazines that are mass-printed.
Technology
explainlikeimfive
{ "a_id": [ "eva1hyu" ], "text": [ "Magazines are typically done on offset presses, using standard sheet sizes. The type of paper printed on is specified by the customer, generally proofed before a full production run. Matte vs. Glossy is often a varnish applied on top after printing is done, before it goes to binding. There are usually multiple machines that go into making the finished product. I work for an OEM that makes/designs/services these types of machines, it's a huge industry." ], "score": [ 3 ], "text_urls": [ [] ] }
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ciz0yx
Why do cable internet providers offer such asymmetrical speeds compared to their fiber counterparts? E.G. Their upload speeds are so much slower than their download speeds.
Technology
explainlikeimfive
{ "a_id": [ "eva27gn", "evaqucy" ], "text": [ "There is almost always a bigger need for downloading information than there is for uploading it, and the cables that cable internet travels over are more limited than fiber optic. So, cable and DSL companies prioritize download speeds by using more channels for downloading than for uploading.", "As others have said it’s due to most residential customers are surfing the web, essentially downloading each page they view. Hardline coaxial cable (the cables on the poles) are only capable of Carrying so much data in each direction. Due to this cable companies prioritize download over upload. This is a generalization of your question because there can be a lot of other factors like node capacity (maximum number of people who can be plugged in in a given area) and CMTS limitations (CMTS is the brain of your cable companies internet) also keep in mind that the industry evolves with demand and 99% of people are not uploading massive amounts of files over the Internet, so there is no real problem to address. I’m sorry if I don’t explain it in simpler terms I just wanted to give validity to what others are saying Source: Broadband Technician for the past 4 years Edit: almost all cable companies use fiber optic but recently they have been bringing the fiber to the home and almost all new build outs for cable companies are strictly fiber optic." ], "score": [ 10, 3 ], "text_urls": [ [], [] ] }
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cj131z
What’s the importance of restarting your computer after updating an application/program on a computer?
Technology
explainlikeimfive
{ "a_id": [ "evafwn4", "evafllg", "evafxl1" ], "text": [ "Computers run on sets of instructions telling it how to run all the parts of the computer and build an interface so you can use those parts. Say you're following a recipe for a cake. Then you finish the cake and someone comes along with a better way to make a cake by adding another ingredient and changing how much salt is used. You can't unbake your cake at this point to try it out. You have to start over from scratch and remake the cake. So when an update happens, you have to restart the program or even the whole computer to before you were using those instructions that changed. So the computer can follow the newer, better instructions when it builds you your interface.", "Some files maybe in use by the OS or Application and can’t be uttered updated so a reboot allows that to happen as they are not in use", "You know how you can't open a file when another application has it open? Well some of the files on your hard drive are opened by the operating system (windows, linux, macos etc) and the operating system keeps them open right up until you switch the computer off. When you install an update, you might need to replace one of these files that the os has open. Since the os has it open, your installer can't also open it. The solution is to tell the os to update that file next time the computer starts before the os opens the file. So until you do a restart, the update isn't fully complete." ], "score": [ 15, 5, 3 ], "text_urls": [ [], [], [] ] }
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cj20mp
why is a chip on a credit card considered ‘safer’ than swiping the magnetic strip?
Technology
explainlikeimfive
{ "a_id": [ "evam62a", "evb88yq", "evap26k", "evapvrd", "evawl9q", "evam0if", "evav4bg", "evaxxao", "evaq19h", "evazt1m", "evb44x0", "evat59g", "evaxd60", "evbi2me", "evb5wwp", "evax7gh", "evaykz5", "evbh45e", "evaycyd", "evayaq2" ], "text": [ "Magnetic strips can be much more easily duplicated than the chips. The strip can be duplicated just by reading the swipe, since the data it gives *is* the data it has. The chip, instead, gives an encrypted code based on what you ask it by combining the value you gave it with a secret one it has, and even if you ask it hundreds of times, you won't be able to figure out the secret number it stores inside it. When the reader says to it \"what value do you get when I give you Value Y?\" the chip responds with what it gets, and then that is checked by the institution that issued the card (who know the secret number too so can do the same calculation and see if the results match).", "The magnetic strip is like a secret code that lets you buy things. I can copy your secret code and use it to buy things. The chip is like a little man who makes secret codes that can each be used to buy one thing. I can copy the secret code but not the little man. Because the secret code only works once and for a limited time, and in one situation, stealing the secret code isn’t useful. You can’t steal the little man without doing a lot of work.", "Others have already explained how it works, so I will go to the practical side a bit more. You know how in the news, big companies sometimes have hackers steal credit card information? If they steal information from a magnetic strip, then they have your credit card number and can now buy things on YOUR credit. If they steal the information from a chip it's useless to them. They can't use it to commit fraud because the numbers the chips makes can only ever be used once. So using the chip makes you hacker proof in any places you use the chip. Note that it does really protect you much if you've ever used both at the same place or if you use the actual card number online. So it helps a lot, but it's not foolproof.", "If only in the USA we'd go the next step to \"chip and PIN\", I wouldn't feel like a caveman when I go to other countries and they have to find a pen for me to sign a receipt. Or we could just go totally backwards and I could carry a special individual seal with me, and they'd scramble to find me some wax.", "The chip is actually a tiny computer that is powered by the reader. It has a secret number inside of it that cannot be read. Only the bank knows the number. There's no way to ask it the secret number. Instead, you can only give it another number, and it will do some math on that number and its secret number and tell you another number. That's what happens when you read the card. The bank picks a number and asks the card to respond. The bank does the same math, and if your card has the same secret number it must be legit. Now, you're probably thinking someone could figure out the secret number by just getting it to do the math enough times. But the numbers involved are so big, this will take too long to be practical, more than 10 years to get enough numbers to have a shred of making a guess. Even with very modern computers. That's longer than your card's expiration date so it's fine. And if computers get fast enough the math fails, the banks can simply change the chips to use new algorithms and new, bigger numbers that take even longer to crack.", "The chip causes the terminal to generate a random number sequence which is then checked against your card issuer. It's safer than a magstripe because you can't simply clone the chip like you can the numbers on the magstripe. Of course, as long as cards still have the magnetic stripe, they're still vulnerable because there are terminals that don't accept the chip, but it's a start.", "In theory they were supposed to be. Until they had to create fallback in case the chip couldn't read. Yes, fallback to mag strip. So now fraudsters just put a bad chip in a stolen mag strip card. 3 trys on chip... then you are back in business stealing other people's money via mag strip data.", "A *really* ELI5 explanation is that the chip effectively produces one-time card numbers that are only valid for single transactions, whereas a magstrip always produces the same card number. It's not quite that simple, but that's sort of the idea. Since the data produced by the chip card is only valid for a single transaction, a seller or middleman (card skimmer, hacker, etc) has no incentive to store or reuse the data, unlike in a magstrip transaction, in which the actual card number is used and can thus be reused to, eg, drain the account or make fraudulent purchases.", "One thing to note that wasn't mentioned yet, is that outside the US it is a \"chip and PIN\" system. If someone steals the physical card, they still can't use it at a terminal without knowing the PIN. The PIN wasn't implemented in the US, so in that sense the card is just as vulnerable as it was before. Countries outside the US have had this implemented properly for years. Major retailers in the US still haven't enabled chip capability for some reason.", "People are forgetting the number of your card is ON YOUR CARD. I am guessing many people dont know cards used to be manually imprinted on a piece of paper. Nothing is stopping a dishonest waiter or cashier from taking a photo of your card or writing down/skimming the pin number, cloning the card and using it as a credit card ANYWHERE IN THE WORLD. They dont even need the PIN to use it as a clone. These cards are so incredibly vulnerable its mind boggling.", "I'm not sure if this has been mentioned, but from what I understand, who ever has the subpar tech is liable (I'm guessing this depends on state/ county jurisdiction). You have a chip reader but the gas station only accepts swiping? Gas station is responsible. The chip tech alleviates skimmers. It's easy to read a swipe with your card, but now they have to break through the encryption. Always trying to stay a step ahead.", "mag strip can be copied easily while the chip keeps its secrets to itself. also the chip is smart and generates a unique digital signature for each transaction while the mag strip is just dumb data storage.", "Say you've got a door that can only be opened with a password (your bank account) but you don't want to say the password, because you know there are people listening (whoever owns the card reader). It is actually possible to prove to your bank that you have the password without saying it out loud. What you do is you ask them to create a puzzle that can only be solved by the person with your password. Then you solve the puzzle (this is what the chip can do). Your bank knows you have the correct password because you solved the puzzle, but you don't ever have to say your password out loud. Swiping just tells the machine your password.", "ELI5 Answer Mag Swipe Card Terminal: Hi who are you? Card: I'm Number 5538... Terminal: My system says your card is valid; Are you a copy? Card: I'm Number 5538...; with an expiry of 02/21 Terminal: OK Great Chip Card Terminal: Hi who are you Card: I'm encrypted code XyM2... Terminal: I connected with my external resources and they say you are valid; Are you a copy? Card: I am encrypted code version 283 Terminal: Sorry my resources say the next available encryption is version 287 I think you are a copy and will decline this transaction. The system is much safer from replication not from physical thief. That is where the signature or PIN adds value when used correctly.", "Because the fact that you had to insert it 30 times before being recognized ensures that you were indeed at that establishment.", "Magstripe was developed in the 1960s. Basically the first one was made with cardboard, recording tape, and a clothes iron. This is a great article - URL_0 The data on the magstripe is static. The EMV chip (and EMV Contactless) is dynamic.", "Basically, the strip does nothing more than give the CC number and the stuff on the front of your card. No more secure than just calling a pizza place and reading your cc # to them. The chip is a secondary bit of info that is more complicated than that, and both need to be present for chip machines.", "Suppose there's a bridge guarded by a troll. A magnetic strip is like a password written in troll language that any troll can read. So to get across the bridge you show him your troll scroll and he lets you in. But now he knows your password so he can write down your password on another scroll and use it to get into your castle which is guarded by a different troll. The chip is like a tiny magical pass fairy. So when you get to the bridge the troll can ask it a random question like, what's your fairy mom's name and the fairy will know the answer. But if that troll goes to your castle that troll will probably ask a different question and the bridge troll won't be able to use his answer to get in to steal your gold.", "The chip is encrypted and the data is non-static. The mag stripe is plain text and static. Easy to dupe with a mag stripe writer. Chip costs more to duplicate and must be reverse engineered/un-encrypted to do so.", "Imagine your parents gave you a secret password you could use to get a cookie. Let's say the password was \"47\". You say \"47\" to your parents, and they automatically give you a cookie. Say it again, another cookie. Pretty cool, right? Now, when your friends are over visiting, one of them sees you saying \"47\" to your parents and getting a cookie, so he gets the bright idea that he's going to say \"47\" to them, and they give him a cookie, too. \"Right on!\", your friend says, as he says \"47\" over and over again, getting all the cookies from your parents. So when it comes time that you want a cookie, you go to your parents and say \"47\" and they don't give you anything, because there aren't any more cookies because your friend ate them all. Now, imagine your cookie word was \"1 – 7 – 3 – 4 – 6 – 7 – 3 – 2 – 1 – 4 – 7 – 6 – Charlie – 3 – 2 – 7 – 8 – 9 – 7 – 7 – 7 – 6 – 4 – 3 – Tango – 7 – 3 – 2 – Victor – 7 – 3 – 1 – 1 – 7 – 8 – 8 – 8 – 7 – 3 – 2 – 4 – 7 – 6 – 7 – 8 – 9 – 7 – 6 – 4 – 3 – 7 – 6 – Lock.\" There's no way your scheming little friend can remember all that, but as long as you do, your cookie supply is secure. Now, that's a lot of numbers to remember, but if you had a little chip in you, you could store all that easy." ], "score": [ 16390, 2189, 1355, 324, 294, 56, 34, 34, 28, 9, 7, 6, 6, 6, 5, 5, 4, 4, 3, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [ "https://www.quora.com/When-was-the-first-credit-card-with-a-magnetic-stripe-issued" ], [], [], [], [] ] }
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cj25gy
WHAT is the Fortnite World Cup? How do you win? Why is it a big deal? (F45 asking, be nice)
Technology
explainlikeimfive
{ "a_id": [ "evamu3s", "evan7xb" ], "text": [ "Fortnite is a very popular videogame. The Fortnite World Cup is the World Championship for that videogame. Why is it a big deal? The prize pool for that World Championship is about $30,000,000 and many people want to win a portion of this.", "You play the arena mode in regular fortnite and there are qualifiers for everyone above 300 points (which means the above average players) if you placed near very top (top 1-5, for some regions it was 1, some it was a little more) in your region for that week, you got to go to New York to play the in world cup finals. Winner gets $3mil, iirc they were giving away $30mil total in prize money. It’s a big deal because out of 40million people who participated in the arena mode, only 200 made it to the World Cup. Everyone who went there got a minimum of $50K. Feel free to ask questions sorry if I explained it badly." ], "score": [ 3, 3 ], "text_urls": [ [], [] ] }
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cj3rpj
How do some cars have a birds eye view of of the car when they’re parking?
Technology
explainlikeimfive
{ "a_id": [ "evay0ha" ], "text": [ "The car has cameras in the front, rear, and in the two side mirrors. Those images are stitched together (kind of the same way that your phone creates a panorama) to give a kind of 360° view of the car's surroundings. That image is then displayed in such a way that it looks sort of like a bird's-eye view instead of like the 360° panorama that it actually is." ], "score": [ 16 ], "text_urls": [ [] ] }
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cj4p93
How does the Game Genie work?
Technology
explainlikeimfive
{ "a_id": [ "evb5ci9" ], "text": [ "The Game Genie and Game Shark peripherals were special cartridges that sat between the system and the game cartridge. This lets it read and modify memory in any way it wants. The special codes you put into it contain the memory address and the action to perform. It can be as simple as \"Set this value to X and don't let it change\" or something more complex like \"When the 'A' button is pressed, add 4 to this value\"." ], "score": [ 10 ], "text_urls": [ [] ] }
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cj8ort
How can someone make a fraudulent transaction just by knowing my Debit Card Number and CVV?
ELI5 : Generally, every transaction that I perform using my card needs me to either enter the PIN code or a Password/OTP(in case of online payments). So, I was wondering why it's general practice to keep the debit card number secret. PS : I get that obtaining the card number and the CVV is the first step for a fraudster, but isn't it just pointless to keep it hidden from everyone else if using only these, no one can make a fraudulent transaction? PPS : Sorry, if I sound dumb!✌️
Technology
explainlikeimfive
{ "a_id": [ "evbruk2", "evbvpgr", "evbruea", "evbs35e" ], "text": [ "i didn't need any Pin or anything to add my credit card to amazon, they might get suspicious if the name on the adress is not the same, but that's easy to change.", "In the United States, you can run a credit card using just your credit card number and CCV. PINs are only used for ATM/debit transactions, not transactions that use the Visa/MasterCard networks. Some online stores or gas stations use zip code or address information as another verification, but it's usually pretty easy to look that up if you also get someone's name.", "In the UK these could be used to process an insecure payment (higher transaction fee) on a card machine. if they had the number of the first line of the address and the postcode/zipcode that would be a secure payment.....this is how payments are taken over the phone at a takeaway", "In many cases, using a PIN or password is an optional security step that the merchant processing the card sets up (at additional cost to them). But it is not generally a requirement, and there are plenty of merchants who will process a payment without that level of security. A thief who obtains your card info only needs to know of one of those merchants to do some damage, especially with a debit card, and they likely know of many. When I ran a small business just a few years ago, card no. plus CVV was all I needed to run a transaction through my on site terminal. Our on line payments required a higher level of security, but not our \"card present\" transactions. /Edited for typos" ], "score": [ 11, 6, 3, 3 ], "text_urls": [ [], [], [], [] ] }
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