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gocoqs
|
how are 16:9 and 4:3 not the same aspect aspect ratio?
|
Technology
|
explainlikeimfive
|
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"\"A 4:3 aspect ratio means that for every 4 inches of width in an image, you will have 3 inches of height. In mathematical terms, that comes out to the screen being 33% wider than it is high. A 16:9 aspect ratio means that for every 16 inches of width in an image, you will have 9 inches of height. Unlike the 4:3 aspect ratio, a 16:9 aspect ratio is 78% wider than high\" Source: URL_0",
"I see the confusion. If you square both of the values in a 4:3 ratio, you certainly end up with 16:9 but thats not how ratios work. To simplify 16:9 to be similar to 4:3 let's divide both sides by 4. 16/4 = 4 so far so good. The ratio is 4:? thus far 9/4 = 2.25 so the ratio at this point, if broken down to be similar, is 4:2.25 which is not 4:3"
],
"score": [
7,
4
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"http://www.steves-digicams.com/knowledge-center/how-tos/digital-camera-operation/the-difference-between-a-169-aspect-ratio-and-43-aspect-ratio.html#b"
],
[]
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[
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|
gody1g
|
. Since VPNs can change your IP address, can you connect to a WiFi even if your device is originally blocked from that same WiFi?
|
Technology
|
explainlikeimfive
|
{
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"frfb0lc"
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"text": [
"Imma go with no. When your device connects to wifi it doesn't actually use an IP address initially, but uses the MAC address, which is kind of like your device's personal signature. It is possible to change your MAC address, but a VPN isn't where that happens. Wifi routers can block a particular device by excluding that device's MAC address. Your WiFi router does also assign a local IP address, but that is done by the router while you are establishing a connection and is only used inside the local wifi network. A VPN won't change this local address. The VPN only interacts with your device once you actually connected to the internet, which happens AFTER you establish a wifi connection. The VPN then assigns an IP address for your device, which is used to identify your device when doing stuff on the internet. So, in summary, while you are connected to WiFi AND the internet you actually have at least two IP addresses. One is your internet address (what the rest of the world sees and uses on the internet) and one is the local network address (what the router sees and uses). Changing your internet address with a VPN doesn't change your local address and doesn't change your ability to connect to a wifi router if you are blocked."
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4
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goekrg
|
I kind of get how the old computer mouse with the ball would work. How do the newer ones with a red light work?
|
Technology
|
explainlikeimfive
|
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"text": [
"Optical mice have an LED (the red light) that shines downward onto the surface before it reflects back and is picked up by a sensor. A lens collects the reflected light and forms an image. It would appear as a small black and white section of the mousepad or surface the mouse is on. While this is going on, a camera is taking rapid pictures of the image (~1600 per second). The pics happen so fast that they overlap. An optical navigation engine in the mouse compares those pictures and looks for commonalities between captured frames to determine how far apart they are. That information is then converted into X and Y coordinates to indicate the movement of the mouse.",
"TLDR: old ones had little cylinders inside that were rotated by the turning of the ball. The number of rotations determined how far it scrolled. There were different cylinders that measured the x axis and the y axis (and possibly diagonal). The red light does a similar thing but by projecting light or laser onto a surface and then measuring how far in each direction you have moved the mouse based on changes in the image that is reflected back into it by the bright light it shines onto the table. That’s why it doesn’t work on very shiny or clear surfaces - no reflected surface to measure.",
"They have a tiny camera that takes pictures of the surface the mouse is on, and use a basic computer inside the mouse to detect when and how the mouse moves. Red LEDs are commonly used because they're cheaper and the specific type of camera is more sensitive to red light."
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3
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"url"
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gog7sp
|
- with captchas, multi factor authentication, email verifications and so much more at disposal how are the biggest social platforms still riddled with bots in high percentages ?
|
Technology
|
explainlikeimfive
|
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"A lot of these processes can be done programmatically. Often times its more of an annoying hindrance than an impassable boundary.",
"Bots can be written to handle multi factor authentication and email verifications. And it is possible to hire people who solves captchas for bots all day. But a lot of social media platforms will actually promote the use of bots as they do add functionality and integration to their site which makes people want to use it more. For example look at the bots which will post a link to your blog whenever you post a new blog post. If the platforms disabled these bots then it is unlikely that you would post a link manually to all your social media platforms and you would only post it to a couple of them. This would make people move to those platforms instead. So the social media platforms risks loosing users if they disable good bots. However it is very hard to distinguish a bot posting links to new blog posts or status updates and bots posting misinformation. This is something which requires intelligent people who have time to sift through these posts and their contexts. There is no way for a computer algorithm to distinguish good and bad bots.",
"The 'defending side' is always at a disadvantage. The bot maker only has to find one vulnerability that lets them circumvent the defenses. The defender has to find and block all vulnerabilities.",
"Modern Captchas are part trying to filter out bots, and part trying to train the next generation of smarter bots. Have you noticed that you're often asked to identify street signs or check all the boxes with cars? These are exactly the challenges currently facing automated driving cars. If doing those tasks was so easy anyone with a botnet could do it, automated driving would be cheap. Since it currently isn't a trivial task, coming up with a bot net capable of picking out where cars are in a photo is prohibitively expensive for most but not all bot nets. Anyone with a neural network trained well enough to do those tasks will charge a premium for such, and creating one from scratch would require a whole lot of people clicking where the cars are on an image. When companies like google set their captchas on the bleeding edge of what challenges AI are currently trying to solve, they not only filter out low funded bot nets, but improve their own AI by training it to do better. It is only a matter of time before technology catches up with the bar set though, at which point the bar will have to be moved higher."
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"url"
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gogccq
|
How does Astronomers discover Planets and other space objects Billions of light years away?
|
Technology
|
explainlikeimfive
|
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"text": [
"They don't in general directly observe the planet, but as they pass in front of the star (between the star and us) they block some of the light from the star, when this happens on a regular time pattern you can work out that it is an object (planet) passing in front of the star, the gravitational pull of a large planet as it orbits the star can also mean that the star \"wobbles\" slightly in the orbit. URL_0 Also it isn't billions of light years away that is too far away."
],
"score": [
3
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"https://youtu.be/AnYye_c8rI4"
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"url"
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|
gohz5i
|
What do all these Headphones Audio Features specs mean?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Speaker diameter is basically the size of the driver you're putting on your ears; its a useless spec. Speaker sensitivity is how loud the headphones get with 1mW of power (i think its 1mW), unit of measurement: decibel/mW (db/mW); quite useless as well, unless you're an audiophile nerd. Speaker impedance is the resistance of the circuit in the driver, ties back to the Speaker sensitivity; again, quite useless as well, unless you're an audiophile. Speaker Frequency Range: the range of frequencies the driver can reproduce. often around 20-20000Hz, most of us only hear up to 16-17kHz; again, quite useless as well, unless you're an audiophile. Noise cancellation system: i have zero idea what this is, most probably some classy and cool words to make it sound great and expensive. tl:dr :most specs on headphones are pretty useless to the general public LOL"
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3
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[
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goj7n8
|
Why does it take half a year to decode an airplane's black box?
|
In light of the recent plane crash in Pakistan, reports suggest that it will take 6-7 months to decode the black box. The company that made the black box surely knows how to decrypt their encryption, so why would it take so long? Also, assuming the encyrption is super-complicated, what sensitive data would warrant such encryption? Is it just voice recordings, or something more? Edit: I really appreciate the responses. Not only does it answer my queries but also expands on a lot of questions I hadn't even thought to ask.
|
Technology
|
explainlikeimfive
|
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"Imagine someone’s car crashed and you want to understand what happened. You have a recording of the crash, but it’s not a video - it’s a recording of the exact speed each wheel was doing, what the brake pressure was, what the position of the accelerator was, the engine temperature, the air con setting, and so on. You’d eventually be able to understand a lot about the crash, but you’d need an expert to look at all that data and tell you what it meant. Now imagine that for an aeroplane except there are several hundred times more pieces of data to look at, and the ultimate cause of the crash may be buried deep in one obscure sensor reading. That’s what you’re ‘decoding’ with a black box. Edit: thank you for the gold and awards! My first ever!",
"Normally they are slightly damaged due to the conditions of the crash, then it isn't the decoding that is a problem it is interpreting the data, the data tells you what happened and when but not all the other things that happened. So an engine failed at 11.03 20 seconds later the plane goes into a steep dive. Is it crashing or are the pilots trying to dive to restart the engine or even put out a fire?",
"Pilot here. **TL;DR... The time is in the full investigation, not just the box data.** If a Flight Data Recorder is intact, getting the data is relatively quick and easy once found. There may be some damage to components or incomplete information that requires interpretation. Forensic techniques can get some of that data back. Relative to the whole endeavor, it's a small portion of the effort. That data is correlated to other evidence to figure out what happened. That evidence is gathered physically and through interviews and records. Here's a non-comprehensive list of things an investigation will be looking for: * Aircrew Background: Mannerisms before flight. Diet. Illness. Fatigue. Alcohol. Medication. Stress. Major life events. Reputation. Training history and performance. Identified human factors in all of this history. Personality (Excess/Lack of Confidence, attitude toward bending/breaking rules, communication skill etc). Group Dynamics. Social barriers (see Korean flight that crashed in SF). Conflict. 24hr(or more) history to include what they did day of, night before, day before, even week before. Family Dynamics. Things they've said not just in the cockpit, but out of the cockpit. * Aircraft Operation: within SOP/Regulation/Training/Aircraft Limits. Deviations from normal operations and reason. Acceptance of failed equipment (there's always failed equipment on a plane, there is guidance on what is safe to take flying), unusual control inputs (too aggressive, not aggressive enough, autopilot usage), systems setup (navigation used, parameters such as Baro Bug set correctly) * Environment: weather, history of aircrew flying in said weather, equipment and qualification suitable for weather, aircraft/aircrew/airport/maintenance/operational/navigational complications due to weather, airport/control operations in general (pace, safety, same considerations for controllers as there are for aircrew), company culture, dispatch helpfulness, clarity in communication. * Physical/Engineering: Part exceeded limits. Part failure due to random/user error/malice/engineering/maintenance/unforeseen incompatibility. Personnel access to those parts same considerations for maintainers/engineers as for aircrew and controllers and their companies and training. * Training: Adequate. Culture... Just fill in the gaps already because I've only got like half of them. All of this has to be strung together to figure out and rule out causal factors to an incident, and come up with recommendations to prevent further related incidents, and do so with a high degree of certainty that all of this is correct.",
"Im no black box expert, but from what I know, it's basically a log of all of the aircraft's sensors and all of the things the pilots did. Imagine a massive excel file with hundreds of columns(vertical) . Each column is a sensor, be it altitude, aircraft nose angle, air speed, engine power, amount of fuel, door closed sensors, etc, anything you can imagine that an aircraft might have. Then every second, the value of all the sensors fills out a row(horizontal) in that excel file. Well, that's a shitload of data, and looking through an hour or more of that pure data is going to take a lot of time. You'd be looking for abnormalities in sensor readings or weird combinations of sensor values, sensors that stop working, pilot actions that didn't result in the expected sensor response, etc. It's probably just a ton of crap to go through, and unless you find a real \"smoking gun\" figuring out what exactly happened would take a lot of time a knowledge of the entire aircraft. That make sense?",
"No expert, but decode in this sense doesn't mean it's encrypted for security reasons and they're thinking \"oh shit, we forgot the password\" it's more to do with the complexity of the task at hand. It is also extremely important to make sure all the data is correct and none of it is corrupted (bear in mind, this box went through a hell of an impact) and if something is reading the wrong figure, it could screw up the whole investigation. So they have to error check and back up (safely) millions of lines of code reporting everything that happened, from thousands of sensors, millisecond by millisecond. Not an easy task.",
"Finally a question I can answer. I’ve been an avionics tech for about 10 years. A Cockpit Voice Recorder (CVR) and Digital Flight Data Recorder (DFDR) are what is commonly revered to as the “black box.” Fun fact, they are in fact not black, but international orange and typically consist of two different systems. One used to record pilot voice and the other used to record aircraft flight surface data. I am not sure at all where this idea come from that it takes 6 months to “Decode” that data as a recent crash only took us 10 days to decode. Sometimes it can take longer to decode for a few reasons however. 1. It’s destroyed - the CVR and DFDR are in a very tough case we simply call the “Crash Survivable storage unit.” (Real original I know.) Even so, this case may not survive an impact into a mountain. In this unfortunate case we simply may not be able to retrieve the data. 2. It got “lost” - this is pretty typical in underwater scenarios but we have underwater locator beacons that operate at a depth that I cannot disclose. Just know that it’s pretty deep. Sometimes though, it may exceed this depth and it makes it difficult to late. 3. Some maintainer didn’t calibrate the damn thing correctly. - this suck because it’s our own people’s fault that we can’t quickly calculate what happened. People usually go to jail for this stuff though so there is that.",
"It's probably inaccurate reporting. Most likely they can read it right away, but it's the full analysis what takes time. Sure, the black box says what each sensor reported, but what does that actually mean? Eg, did the black box record low fuel because there was too little to start with, or a sensor malfunctioned, or there was a leak, or some unexpected condition caused the airplane to burn fuel faster than normal? They may need to collect all the wreckage and look at the remaining bits, and interview survivors. They have to be careful with these things, and make sure not to blame the wrong thing just because that can cause additional harm.",
"When people use the word decode in contexts like this, they're talking about taking raw data, packed for efficient storage, and decoding it into a form that is understandable by humans, and then working out an interpretation of events. Normally extracting the data is easy, but if the recorder is damaged, it could require specialized skills and tools to retrieve and decode. Normally the vast majority of the time is just spent piecing together events, and making sure you got it right and every anomaly in the data is explained.",
"this is bad reporting. The FDR will be repaired and all the data will be pulled. it's raw data, but from that they can build a pretty good picture of what was happening to the aircraft's systems leading up to the crash. That data will be compared with crash data from other aircraft and compared with findings from air accident investigators who have examined the wreckage and any eye witnesses/survivors/video footage and the Cockpit Voice recorder which has all the pilot and copilot's conversations right up until they die. At the 6-7 month stage the press release will be \"we're pretty sure the plane crashed because of XYZ reasons\"",
"It depends on the type of aircraft and the operator but usually there are two \"black boxes\" -- one is the CVR (cockpit voice recorder) and the other is the FDR (flight data recorder). The FDR records panel settings, alarms, fuel flow, and similar. If they are damaged in a crash it can be difficult to extract the information. Sometimes it requires the expertise of the regional transportation safety board and sometimes it even requires the original manufacturers to extract meaningful information. All of this needs to be methodically analyzed in an attempt to understand what happened leading up to, during, and sometimes even after a crash. Sometimes it's obvious and sometimes its a major puzzle.",
"The data is generally decoded quite quickly. The meaning of the results is tested and analyzed by many groups before the results are released. It's not about getting the data off, it's about analyzing why the throttle was in a high power position, and the engines were spinning slowly. That can happen from fuel problems, engine damage, control problems, or other things. So they don't say \"engines were not making power, we don't know why\", but don't publicly reveal the results until the meaning and cause is known.",
"I doubt very much the ''decoding'' will take almost anytime at all. I would assume a Black Box is nothing more than a hard drive with minor protection (we use something similar on vessels at sea, albeit much more simplified ones - almost anyone with a laptop and usb cable can access the data). However, the interpretation of that data, now that is another matter entirely. Like mentioned several times here already there are going to be many channels of data,m raw data. These data points have to be verified as correct/corrupted, brought out of it's raw state to something we can understand, compared with known aircraft data to figure out what happened with the aircraft. Then you gotta try to make sense of that, coupled with pilot voice recordings, try to figure out what was actually pilot input, what was actually the craft ''just doing things'', and if any external input was present. That takes time, and really needs to be done without outside pressure on to finish fast or you run a (bigger) risk of drawing wrong conclusions on what caused a certain behaviour in the craft than usual. And that is only factual input/output as being told by inanimate sensors. It will tell nothing of intent from people (unless loudly stated by pilot in cockpit and believed by investigators), especially if outside ''input'' is added in the mix. If it's data clearance only I'd say 6-7 months is perhaps a bit slow, if it also includes a commissions investigation it is rather on what it takes, perhaps even a bit on the quick side.",
"Hey! I work on this equipment! Here is my input. It doesn't take this long at all to get the data or even put it into a video format for peoples viewing. This process takes a few weeks from recovery of the black box to someone sitting and seeing a finalized video. A download of the data takes at most 1 hour on most different \"black boxes\". Fun Fact the actual color is \"International Orange\". Nothing black about it. But like others have pointed out, it take awhile to figure out what exactly happened. The public will not see any of the data/video until experts have agreed what happened or at least come up with a finalized report. Some things in the comments that I feel need to be addressed for correction or clarification is: Most DFDRs (blackboxes) only record from last power on to last shutdown or a limited amount of time like 12 hours. For crash investigations you typically only need to analyze the last few minutes to see what went wrong. The CVRs (cockpit voice recorders) are usually very limited on recording time(some 4 hours) due to the Pilots Unions because not all of the cockpit lingo needs to be brought up and become public information for privacy reasons. Imagine a pilot who is now dead being heard on takeoff about how he hasn't gotten laid in weeks from his wife but thank god for his mistress in New York. Unions and crash investigation teams work hand in hand to make sure laws and union agreements are kept in mind. That movie with Denzel Washington (Flight) shows good examples of Unions being a big part of these investigations. Someone asked the question about the data on the blackbox after normal flights. This is usually just dumped after each flight by the next flight recording over or sometimes frequently downloaded and sent to engineers to analyze the data to make sure the plane is recording this information accurately just in case it does one day crash.",
"So imagine a black box is like a book in a foreign language, like Chinese. You open the book as an English speaker, and you just see a bunch of Chinese characters. Now, you can feed that text to google translate, and it will provide a literal automated translation almost instantly. The material is “decoded” very easily. But once that text is translated, people who actually speak both languages will go through it, analyze the translations, change things that are wrong or need to be explained with different words because of langue differences. This takes time to produce something that actually makes sense to read as a native English speaker. The same happens with a black box - you can plug a computer into it and pull the data off very quickly. But the data doesn’t tell you what happened, let alone why it happened. It’s just a whole bunch of different measurements, sensor readings, and logged error codes. Interpreting that data - making computer models, walking through a series of events step by step, to see what the likely cause of the crash was, takes time and investigation by aviation professionals, regulators, and engineers.",
"As others have mentioned, the analysis is the long part. But ensuring integrity of the data is a huge challenge as well. Plane crashes are violent affairs, and getting to the storage media, and getting the data off in a safe way is a forensics and computing nightmare.",
"AliHB brings up a good point. If the company that makes them can't read them, how do they know they're working? Why \"invent\" a way to read them after the fact? Whichever system they use to record the data, there should already be a user friendly system to read the data.",
"Decodeing the flight data recorder and the cockpit voice recorder dont ussually take very long. BUT. An accident investigation is a VERY detailed investigation that involves more than just the data recorded by the aircraft. Investigators dont usually reveal the results of any part of the investigation until ALL parts of the investgation and its reviews are complete. This may take many months.",
"Basically a black box regards all the data that is occurring, think of the information as words. The words are then put on the page in just every which way. The information isnt in any sort of order or make any sort of sense. It is up to the engineers to take those words and put them into a paragraph so that it can be understood.",
"I see the first answers are saying that the box takes a long time to understand. Ok, but I have a question about that. Why not simply plug the black box into a simulator and basically just watch what happened? That should be able to quickly show all the parts that are perfectly normal (or at least technically nominal), and it would also be able to say when the data is no longer consistent. I'm sure I'm not the first person to think of this, so what am I missing?",
"There are two parts - 1) Flight data recorder which records hundreds of parameters for last 25hours (new models). It does that in raw data (timestamps, numerical parameters etc). 2) Cockpit voice recorder which records the boom headset microphones and a dedicated microphone channel along with timestamps upto 2hours. Now in such cases the post crash fire and the impact itself damages the structure and maybe data ports etc. So the technical team of the manufacturer have to somehow extract the data as much as possible and verify the integrity if the data, match the the timestamps of both the recorders and produce the files in readable format for the investigators. All this effort takes quite a while aa you can imagine. The final output which investigators use to create an analysis video looks like [this.]( URL_0 )",
"The delay you are talking about isn’t really the delay in downloading the data. Usually the data download is done rather quickly. As others have said, it’s the analysis that takes awhile. Aside from that, NTSB (here in the US) hearings and reports can become slightly political and it takes quite a bit of time to get all of the involved parties to discuss/analyze/vote on probable cause and contributing factors. As a side note, these flight data recorders (the infamous “blackbox” as it’s referred to) have other uses as well. Airline safety departments regularly download the data and company/pilot analysts audit the flights to see where there are potential higher risks in the operation. At my previous airline, I was one of these analysts. It was very fascinating and we were able to improve many of of procedures based on recommendations from those findings.",
"It’s not 6 months to computationally decrypt the data from the device. But the data is pretty raw. When they make a plane they don’t know what might go wrong with it so they record as much as possible of every instrument possible. The data is raw and there’s a lot of it. Piecing through that forensically to reconstruct what happened and actually pinpoint the cause of the crash, and then cross check that against all other available data so you can be confident you know the story of what occurred... that takes time. This process isn’t performed a hundred times a week, either. It’s a rare event and so it’s not like pumping out an electric car which people have been tuning a factory to do, making small improvements over and over day in and day out until it’s fast and reliable. Every crash is different.",
"Assuming, like most others here, that \"decoding\" refers to the publication of a final repost rather than just reading the data. The reposts can be some hundred pages of dense technical detail to understand 1. What happend 2. What [chain of events]( URL_9 ) lead to it happening 3. Which measures need to be taken to avoid this happening in the future Take your pick of [accident investigation authorities]( URL_8 ), you'll find loads of reports, not only on fatal crashes, but all sorts of incidents that shouldn't have happened (and there are [loads every day]( URL_12 )) Then there is also the matter of who (i.e. which state's authorities) actually [take part in the investigation]( URL_3 ). In this case it'll be Pakistan (because it both happened there and the aircraft was registred there; were those different, add another), France definetly (because Airbus; [CFM]( URL_7 ) \\[engines\\]), US probably (see: CFM), unlikely UK, Germany, Spain (because, again, Airbus), people from Airbus, CFM, whoever made the Landing Gear, FDR, and whatever else may be found to have occured. Looks like PIA isn't doing their own [A320 training]( URL_4 ) (website only shows B747 and B777 sims), possibly they'll want to interview who trained the crew (did the have a history of becoming [task saturated]( URL_2 ), not follwo procedures, etc.) So you get people from all over the world together to figure this out. Let's say the landing gear guys sort through the bdebris, find all 'their' parts and figure out why it didn't work. That's one (important) part of the investigation, but maybe it doesn't really tell you why the aircraft crashed (that stuff [just happens]( URL_5 ) [occaisionally]( URL_6 )), because it did not impact any other systems. Then (or probably in parallel) you're looking at the engines (which again, [somewhat optional]( URL_10 )). Depending on how much lab work needed to be done on parts to check for failure modes (and distinguish them from damage due to the crash itself), you've spend a couüle of months at least and still have only parts of 1) and 2) and very little of 3). That stuff [takes time]( URL_0 ) (list of German accident reports, first colunm is the date of the incident, the last colunm is the date the report was published; some have taken multiple years). And when it comes to \"reports\", look who's doing it (and how much they know about aviation), remember \"[Boeing 777 will struggle to maintain altitude once fuel tanks are empty]( URL_11 )\" was a thing. The best thing to do in case of aviation accidents is to forget about them for a year or so), then read the official report. Everything else is pointless speculation. I hope this is somewhat coherent, I should be sleeping for a while now, [but . . .]( URL_1 ) ;)"
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"https://xkcd.com/386/",
"https://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_401#Cause_of_the_crash",
"https://www.icao.int/about-icao/FAQ/Pages/icao-frequently-asked-questions-faq-10.aspx",
"https://www.piac.com.pk/corporate/training/flight-simulator",
"https://en.wikipedia.org/wiki/LOT_Polish_Airlines_Flight_16",
"https://en.wikipedia.org/wiki/JetBlue_Flight_292",
"https://en.wikipedia.org/wiki/CFM_International",
"https://www.icao.int/safety/AIA/Pages/default.aspx",
"https://en.wikipedia.org/wiki/Swiss_cheese_model",
"https://en.wikipedia.org/wiki/List_of_airline_flights_that_required_gliding",
"https://external-preview.redd.it/w4ciy2Lb81hGCvDVMFiju8f3YuiDUZimJkyvF3Fc2xM.jpg?auto=webp&s=f1bcafb149054c90a52586b3c7056fc6bfbd9d44",
"https://avherald.com/"
]
]
}
|
[
"url"
] |
[
"url"
] |
gomd3b
|
; Where exactly do our pictures go when deleted from phone?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frgmncl",
"frgmoel",
"frgnqra",
"frgmuwy"
],
"text": [
"Most computers don’t delete files right away. When you delete something on a computer or phone, the space is just marked as available to be written over by something else. Eventually, something will come along and overwrite the data that used to be the photo.",
"When you delete a file from your computer, the operating system usually just marks the space the file occupies on the ssd or hdd as being available for writing. The data itself remains on the disk until eventually new data will be written into that particular space where your image was.",
"Data on a phone is stored in \"flash\" memory. That's memory made up of specialized transistors. They have a \"floating gate\" which can have charges trapped on them or not, indicating a 1 or a 0. Since the charges are trapped, they remain there even when your phone is powered off. When you tell your phone to delete something, it marks those memory bits as \"unused\". When it wants to write something new into that location, the memory controller has to do some work, because flash memory has some specific requirements. The controller will copy all of the \"in use\" memory locations in that block/page to temporary storage in RAM, erase the whole block/page, and then write back the saved data to the flash memory. Then it can also store the new data. At the point that the block/page is erased, your old photo that you had deleted is truly gone. The charges on the floating gates which contained the information have been removed.",
"With anything digital, deleting a file simply tells the operating system that the memory addresses that held the file are now available for general use. So if you haven't done anything else with the device, the picture is still likely in memory, but it's just not accessible via the operating system. But as you save stuff on the device, the space that held the file may be overwritten."
],
"score": [
25,
13,
6,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
goo2cd
|
How does computer memory actually work?
|
So I might be overthinking it, but I understand that machines store information in certain locations on a drive but how exactly does it work? Like how can a usb drive store thousands of songs? Edit: just to be clear I mean how does it physically work
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frgy18x",
"frh8hqw"
],
"text": [
"First: how does it work conceptually? Data is stored in the form of ones and zeros using binary. Any type of data can be encoded this way, including songs. A USB drive contains space for many, many ones and zeroes and so can store many songs. So how does it do this? USB drives, also called \"flash drives\", store data using something called \"flash memory\" (newer drives use other forms of solid-state storage, but that's beside the point). Flash memory is slower than the in-your-computer memory, but it doesn't reset itself when the power is lost. Think of a flash drive like millions and millions of tiny little bottles, each of which can hold a tiny electrical charge. A full bottle represents a 1, an empty bottle represents a 0. That's a fair analogy. In reality, this memory is made up not of bottles, but of an array of tiny electrical components--but the premise is the same. Each of those tiny electrical components can store a small electrical charge to represent a 1, or can be uncharged to represent a 0. The computer can read these charges in a stream of 1s and 0s to get a sequence of data. That sequence can be taken back up through the layers of the computer to become a picture on the screen, or sound coming from the speakers.",
"First, there is a [memory hierarchy]( URL_0 ), take a look at the pyramid. You want to get data into the working bits of this electric machine we call a computer. The slowest memory would be you - your brain, your observation, your manual input into the machine by toggling buttons... That's not represented here, but data does come out of the physical world, and that only happens because of humans in the first place. So we got to get it to the working parts of the machine. The working parts of the machine are REALLY SUPER FAST, and typically, your CPU is **STARVING** for data. So that's where the hierarchy comes into play in the first place. We can make memory fast first and foremost by PHYSICALLY locating it as close to the working parts of a CPU. That's registry memory. These are small storage units of literally just individual bits or maybe \"word\" sizes, and they are the inputs and outputs of the actual machine. Next up are the CPU caches, which are larger banks of data, but by necessity, they're further away from the CPU. Also, you have to consider how memory is physically built. Registers and cache lines are made from flip-flop circuits, from transistors. They're fast as all hell, but generate a ton of heat and take up a lot of physical space. That means their data storage isn't very dense for their area, they're expensive to operate because of power costs, and because they're so big, some of this technology starts getting so far away from the CPU core that the speed of light starts to have a really significant effect and we're back to starving the CPU for data because you just can't move signals across copper fast enough. That's why there's an L1, L2, and sometimes an L3 cache on a CPU. System memory - RAM, is much bigger, much denser, much cheaper, much cooler (though modern RAM runs hot enough to burn you if you touch it), and much, MUCH slower. They instead use capacitors, tiny electronic components that can hold a charge through capacitance, and dissipate it quickly. To read a value you discharge a capacitor (or not) down a signal wire, which will have a feedback loop to recharge that individual cell. This is SO much slower because flip-flops are stable so long as they're energized - once zero or one, they have a signal wire that is always indicating a zero or a one. But with capacitors, you have to drain the damn things, and that takes time. And then you have to recharge them, which takes time. And then there's that physical distance, all the way across the motherboard. System memory is organized in terms of a [geometry]( URL_1 ). They say computers are byte addressable, and that's not exactly true. Physical memory is not byte addressable, the smallest unit is based on its geometry. So when you want to read a particular byte from memory, you have to fetch the smallest unit that byte exists in, and then subdivide from there. So that's the physical side, then there's the virtual side. You see, memory addresses are an abstraction, since no physical part of the circuitry actually functions on a per-byte level. And abstraction is good, as we'll get into. Enter virtual addressing. Every process running on the machine believes it's the only process running on the machine, and that the whole entire memory address space is its sole domain. In truth, the fact that multiple processes are all running is hidden by the virtual address subsystem. So two programs can have data at memory address 7, but there's a level of indirection where that actually points to different physical addresses in system memory. The processes don't have to know or care. This also lets the computer reorganize data without the process being aware. That's what swapping or pagefiles are all about - some program isn't running that much? Move its data out of RAM and into swap space on the disk to make room in RAM for other processes that have higher demand. When that oft used process needs to access it's data, you can swap it back in literally anywhere in RAM and update the mapping. Every process has a little table of what memory it has allocated. So when you want to read or write, the address you request is mapped though this table - it's how virtual addressing works. If the address you want isn't in that table, that's an access violation. This is how programs don't just go off and read data owned by other programs. There are ways to do it - you need to access memory as though it were a hardware device. And that's another interesting thing about virtual addressing - it doesn't just represent RAM, but really almost anything. Any hardware inputs and outputs can be mapped to memory addresses, so that reading and writing to them routes that data to those devices. Even other programs - it's how one program talks to another, or shares data between them. This mapping doesn't even have to touch system memory. That's what DMA is all about - memory addresses that point right to the disk. Virtual addressing on modern x86_64 processors use 64 bits for the entire address space, but only 2^48 are currently used by most Intel or AMD processors. There are some super computers that can address 2^54. So any process can use at most that many bits for system memory, for hardware or software mapping, whatever. 2^56 is the limit, though, because the upper 8 bits are used as a boolean flag field - true/false values, such as if that memory address is readable, writable, executable, etc. This is why you can't just write bytes to memory and then execute them - those addresses need to be flagged as executable. Hackers have to play some REALLY CLEVER TRICKS to manage to get their exploit code into executable memory and then called upon. There are data sets that are much, much, much larger than 2^48. To handle that, there's memory mapping, and that is simply saying some bytes in my virtual address space access a range in that address space at some offset. When you open a large file in a program, you only need to load a small window of bytes into memory - the bytes you're actually working on at that moment. This is how it's done. Some programs don't do this, as their implementation is naive. ```notepad.exe```, for example, definitely has file size limits."
],
"score": [
9,
5
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/Memory_hierarchy",
"https://en.wikipedia.org/wiki/Memory_geometry"
]
]
}
|
[
"url"
] |
[
"url"
] |
gosg5a
|
Why can't .exe files be opened on a Mac?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frhv6xi",
"frht30l",
"frhy4go"
],
"text": [
"Programs are like pilots and a computer is like an aircraft. A Mac has a cockpit that has different levers and buttons than a Windows cockpit. An exe is a program that only knows how to do stuff in a Windows cockpit. Stick that pilot in a Mac and it has no idea what it's doing. More technical - The exe will share some things in common with the Mac equivalent since they are both x86_64 based machnes. This means some basic stuff like math is the same between them. However, the program will often have to tell the OS to do something for the program. This will usually include things like displaying stuff on the screen or loading data from a file or accessing the internet. The Windows machine and the Mac machine are different in how these tools work and the exe will not know how to do those operations on a Mac. There are tools like Wine that will basically translate those for the exe, allowing the exe to work in a Mac.",
"EXE files are Windows portable executable files containing code written for Windows. MacOS executables use a different file format called [Mach-O]( URL_1 ). It is, however, possible to load EXE files on a Mac. [Wine]( URL_0 ) provides both a program loader and a Mac compatible implementation of the Windows API, which together allow (some) Windows programs to run on Mac and Linux.",
"Trying to open a .exe file on a Macbook is like giving a Japanese book to somebody that doesn't speak Japanese. Are you suppose to read from right to left or left to right? Where does it start? What are these symbols? A program is a set of ordered instructions that allows input, process and output. Suppose an .exe file that was programmed to process the click of your mouse. It provides with a button and awaits your click. The program itself doesn't know how the mouse works, though. It relies on the operating system sending the signal that a click happened. In order to do that the program uses a list of instructions that is available through the operating system. The list of instructions and how they're implemented vary from operating system to operating system."
],
"score": [
11,
5,
5
],
"text_urls": [
[],
[
"https://www.winehq.org/",
"https://en.wikipedia.org/wiki/Mach-O"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
goss8p
|
Why are source code leaks for games so bad?
|
When source code is leaked it always seems to be big news, but wouldn’t people already have the code the moment they downloaded the game?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frhr1nn"
],
"text": [
"The version distributed to users is compiled machine code: code that computers can execute but humans can't read. This code is generated by a compiler, and trying to guess the original source from the compiled code is typically very difficult if not impossible. In simple terms, the machine code is a finished cake. Just having a cake doesn't tell you how it was made. The leaked code is the human readable code maintained by the developers, which exposes how the game works. This is the equivalent to the recipe of the aforementioned cake. This has implications for anti-cheat systems (since malicious actors have far greater knowledge of how the game actually works) and could potentially lead to some security flaws in the code being used by malicious actors before anyone else knows about them."
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
govsfa
|
What is recursion and why is it used instead of iterative loops in programming?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frijaq8",
"fribcbd"
],
"text": [
"Recursion in programming is a function that calls itself to do some sort of task. The way recursion was first explained to me was trying to answer the question “Who are your ancestors?” The answer would be your parents, grandparents, great-grandparents, great-great-grandparents, great-great-great-grandparents, great-great-great-great-grandparents, great-great-great-great-great-grandparents and so on. Using recursion, your ancestors can instead be defined as your parents and your parents' *ancestors*. Who are your parents' ancestors? Their parents and their parents' *ancestors*. The definition of ancestors self-references ancestors as part of the definition, so you don't have to list every generation back to the dawn of humanity, just a child-parent relationship that can be repeated as many times as necessary.",
"Recursion is merely a function calling itself. A standard iterative program would have instructions like: Do the following 10 times: Do something here A recursive program would have instructions like: function DoSomething(count) if count == 0 then exit else Do Something here call this function with argument (count - 1) While they ultimately do the same thing, their implementation is subtly different. The first - iterative - program is far more efficient at the level of machine code. However, in a higher level language, the recursive version is 'safer' because it avoids side effects. In the iterative version, memory will be changing every step of the way. So if we have some other process that expects a specific memory location to hold a specific value, we cannot guarantee it because that memory location is being constantly updated by our iterative loop. In the recursive version, you're creating copies of the relevant memory every time you make that function call. So if an external function tries to access any of that memory, it will always get what's expected. Two other wrinkles: 1. Algorithms are often easier to describe recursively. Consider divide-and-conquer algorithms. If I want to perform some operation on a data set, I'll often split it into two halves and then perform the operation on each half independently. Of course, each of those halves will *also* be split... all the way down to the point where I can perform an atomic operation. An iterative implementation of such an algorithm tends to conceal what's going on. A recursive implementation is self-documenting. 2. Tail recursion. The recursive pseudo-code I posted above has a feature known as 'tail recursion' - the very last statement in the function is the recursive call to itself. This is a special case of recursion that can be deterministically reduced by a compiler into iterative machine code to deal with the performance issues recursion introduces."
],
"score": [
5,
5
],
"text_urls": [
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}
|
[
"url"
] |
[
"url"
] |
|
gowaea
|
Why is a kindle screen easier to read in sunlight than an iPhone?
|
Or just different types of screens
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fridtjs",
"frim1eq",
"fridnbb",
"frjdhh7"
],
"text": [
"Assuming you're talking about a black and white Kindle, these screens are made of e-ink. Basically imagine a grid of little tiny balls that are black on one side and white on the other. Turning some of those to black and some to white will make shapes. This is how e-ink roughly works. A side benefit of this is that once the balls are \"turned\" they don't require any energy to maintain the current state (which is a why such screens have insane battery life). Because these balls are physical objects, they look like normal objects in sunlight. Most other screens are made up of little tiny lights(pixels). Those screens constantly require power to keep the lights on. Since they're just lights, they're a lot harder to see in bright sunlight. Think about the difference in using a flashlight during a bright sunny day and a dark night.",
"The [current top comment]( URL_0 ) explains how the screens work well, but doesn't highlight the key difference: E-ink displays (and some other display types) rely on light hitting the \"pixels\" from the outside. That means when there's more light outside, the display image is also lit up more. Phone displays rely on the light emitted by the display (either tiny LEDs for OLED displays, or the backlight for LCD displays). Thus, if its bright outside, the display itself needs to be artificially adjusted to become brighter (light up more), and it can only do that up to a certain limit. After that, the stuff you don't want to see (reflections, dust etc) becomes brighter than the image you want to see. Old/simple LCD displays (mainly black & white ones, think calculators) have a reflective layer behind the screen and use reflected sunlight, making them easier to see even when it is bright outside, but I think you can't get good picture quality with that and it's hard to read those in the dark. The Gameboy Advance SP is one of the better known devices that has a color display with a \"backlight\" and a reflective screen, but it's actually *front*lit on the most common model. Works great in the sun as far as I remember (and according to what people say on the internet). There is an improved model (AGS-101) that uses a true backlit screen, and while it works much better (brighter) indoors, it doesn't work well in the sun according to what people say (never held one).",
"iPhone displays use OLED technology, or really small and numerous lights to project an image. A kindle display has actual ink in it, meaning it reacts more to light and dark environments.",
"The iPhone screen needs its own light to work and that light is weaker than the sun's light. So it looses and you see less. A Kindle uses no light at all. It only reflects light. The more (sun) light the better. On the other hand: In darkness you can't read your Kindle at all. Therefore most of the newer ones have an inside light added for their own."
],
"score": [
61,
12,
3,
3
],
"text_urls": [
[],
[
"https://www.reddit.com/r/explainlikeimfive/comments/gowaea/eli5_why_is_a_kindle_screen_easier_to_read_in/fridtjs"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
goyf1f
|
What’s the difference between a circuit breaker and a fuse and what are their advantages and disadvantages?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"friqmj4",
"frisxvl"
],
"text": [
"A fuse has a piece of metal in it or something similar that when it gets too hot it melts breaking the connection. While a circuit breaker uses a filament made of material that contracts causing the switch to close under the same conditions. The main advantage of circuit breakers over fuses is that they can be reset by flipping the switch, vs fuses that have to be replaced. Fuses are however cheaper and are still widely used in electronics.",
"A circuit breaker is a switch that will automatically open when a certain amount of current passes through it, and which can be closed again when the load drops. A fuse is a one-time device that melts when a certain current passes through it. For a given circuit, you only need one circuit breaker because you just need to flip the switch back when it trips. If a fuse pops, you need to get a new fuse, but since really a fuse is just a bit of thin wire with a low melting point it's very cheap. If you have something you expect will often overload, a circuit breaker may be the better answer; if it's something you expect will only overload in rare circumstances a fuse might be the better option. Fuses are also more reliable since there's no moving parts; your circuit breakers ought to be tested regularly to keep the moving parts from getting stuck."
],
"score": [
15,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gozhmz
|
Can GPU’s be used as a normal computer processed? If they can why aren’t they if they are so much more powerful?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frix49k",
"frj4lxs"
],
"text": [
"A modern CPU has a small number of powerful cores. A modern GPU has a large number of significantly less powerful cores. \"Normal\" programs wouldn't get much use from having a lot of cores in the same way that games do (games need to run a bunch of easy calculations all the the same time, while \"normal\" programs tend to focus more on small numbers of hard calculations, or calculations that can't be run in parallel). While a GPU *could technically* be used in place of a CPU, it would not be optimized for that usecase and would have significantly lower performance.",
"GPUs are basically MANY cores that all have to do the same thing at the same time, but with different data input loaded into VRAM. This is why GPUs are so great at mining (doing the same thing many times) but could not replace your CPU (which can do multiple things at once on different cores/threads). This happens any time there is branching in your code. then it will be serialized so all cores can do the same thing at once (or wait till the others are done) Additionally CPUs are highly optimized to be general purpose, they prefetch instructions and have branch prediction to reduce the amount of time spent waiting for new data to be loaded."
],
"score": [
18,
4
],
"text_urls": [
[],
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]
}
|
[
"url"
] |
[
"url"
] |
|
gp04hr
|
How do “clock” websites (that track things like global population, national debt) work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frj173u"
],
"text": [
"They simply take the best statistics available and calculate the rate of change over time. For example, if the UN estimated the world population to be 7 billion one year and 7.1 billion the next, this would mean that the population increased by 0.1 billion (100 million) over that period. You could then find out, on average, how much the population increased per day (100 million/365), hour (100 million/365/24), minute (100 million/365/24/60) or second (100 million/365/24/60/60). So these clocks just use these average rates of increase to estimate the current population, national debt etc."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gp2i44
|
How do computers turn binary information into your usual computer programme?
|
I dont know anything at all about the inner workings of a computer. For example, how does it turn «electricity on/off in this part of the computer» into «this pixel on the screen should be this color»?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frje2i2",
"frjtico",
"frjqz1q",
"frjeeq9",
"frjit4w",
"frjeegc"
],
"text": [
"A CPU has two main components, the processing unit and the control unit. The processing unit can store small amounts of data, do basic math and number manipulations, and other sorts of calculations. The control unit does stuff like sending data between different parts of the CPU, controlling input/output to other parts of the computer, and implementing logic that approaches what we would call a program. CPUs also have a Bus, which is a bunch of wires that run in a parallel line that all the other components of the CPU attach to in order to transfer data from one part of the CPU to another. In the case of a 64-bit computer (which most modern computers are), that bus has 64 wires, meaning that it can move a binary number with at most 64 digits. The main effect this has is on the maximum size of a number (in either direction from 0, since binary can do negative numbers) that the computer can handle. CPUs also have internal mini-blocks of memory called registers, which can handle small amounts of data (in modern computers, 64 ones or zeroes per register). The x86_64 CPU architecture that's used on most desktops has four general-purpose registers, named A, B, C, and D (there are technically four more general purpose registers, but they generally contain important information you only mess with if you know what you're doing). The names get changed a bit depending on how much of the register you're using. If you're using the first byte of the register, it's called AL (A lower), second byte is AH (A higher). If you're using two bytes, it's AX. Four bytes is EAX. 8 bytes (64 bits) is RAX. Memory, also called RAM (which is different from storage space), is where your computer stores data it isn't actively using, or hasn't in the past few nanoseconds. Memory on modern computers is what's called byte-addressable (a byte is 8 bits, or 8 ones and zeros, and is the basic unit of data in a computer) meaning that you can think of RAM as a really long straight road with a line of houses on one side, and each house has its own address, and each house can hold 8 bits. If you want a number larger than one byte, say a 4-byte number (also called a long), you would say \"address 245 and the next three after it.\" Among the data in memory is programs, the data used by those programs, and data being sent from the CPU to something else, like video information being sent to your GPU. If you want to implement a program that adds two numbers together, you would need to write it in machine code (which is binary numbers that represent individual instructions like \"move data from this spot to this other spot\" or \"add the numbers in these two spots and put the result in some other spot.\" What we think of programming languages can be converted to assembly language (which is basically human-readable machine code) and then converted into machine code. Here's a simple example of a program that adds two numbers from memory, in the format \"MEMORY_ADDRESS: INSTRUCTION //COMMENT EXPLAINING\": ``` 0: MOV AL, [3] // Move data from memory address 3 to the AL register 1: MOV BL, [4] // Move data from memory address 4 to the BL register 2: ADD AL, BL // Add the contents of AL and BL together, and store the result in AL 3: DB 4 // Declare one byte of data, with a value of 4 4: DB 8 // Declare one byte of data, with a value of 8 ``` In order to make that program actually happen, we need to convert it to machine code. As it happens, instructions like MOV and ADD have binary number representations that vary depend on what they're doing. For example, there's a binary number that means \"MOVE X AMOUT OF DATA FROM MEMORY ADDRESS TO REGISTER. THE NEXT 4 BITS REPRESENT THE REGISTER NUMBER AND THE X NUMBER OF BYTES AFTER THAT REPRESENT THE MEMORY ADDRESS TO LOOK IN\". Those numbers are completely arbitrary and are chosen by the people that designed the CPU. Each instruction is made up of a few smaller mini-instructions that don't take parameters in the way that the instructions above do. From here, it's important to know about the system clock, the instruction register, and the instruction pointer. The system clock doesn't know what time it is, it's just a peice of crystal that oscillates at a known frequency, generating what's known as the clock signal. The pulses from the clock advance the steps of the mini-instructions in a similar way that a metronome advances the beat of a song. (as a side note, when you see a CPU listed as 3.2GHz, that means the clock pulses 3.2 billion times per second, or once every 0.3 nanoseconds). The instruction register is paired with a little counter that increments with each clock pulse. The instruction register is hardcoded (as in hardware programmed rather than software programmed) to have the binary representation of the current instruction (including the parameters) placed in side it, and to output the mini-instruction you need to do for that that instruction depending on the value of the counter. There are usually more than one mini-instructions per clock pulse, and usually with an IN or OUT part. If it's OUT, it means that the contents of the component referred to is sending data out to the bus, and if its IN, it's reading data from the bus. This is how data is transferred between components in the CPU. The instruction pointer is effectively just a normal register, but it contains the memory address of the current instruction. In order to execute the first instruction of the example program above (MOV AL, [4]), these are the mini-instructions that would happen: INSTRUCTION POINTER OUT - MEMORY ADDRESS IN. This tells the Instruction Pointer to output its contents (which is starting at zero) to the bus, and tells the RAM controller to open up memory the memory address that it reads from the bus (which is zero, from the instruction pointer). MEMORY CONTENTS OUT - INSTRUCTION REGISTER IN - INSTRUCTION POINTER INCREMENT. This moves the contents of memory address 0 (which is the MOV instruction itself) to the instruction register so that the CPU actually knows what instruction to execute. This also increments the instruction pointer, so that next cycle it'll look at address 1 and execute that instruction. These two steps are the same for any instruction, since they're required in order to know what the instruction actually is. INSTRUCTION REGISTER OUT - MEMORY ADDRESS IN. This outputs the contents of the instruction register (but only really the part of it that contains the memory address to be loaded, not the entire contents) to the RAM controller. MEMORY CONTENTS OUT - A REGISTER IN. This moves the contents of memory at the address that was loaded to the A register. At this point, the entire MOV instruction has been executed. The mini-instruction counter resets 0 zero, and the cycle begins again, loading and executing the next instruction in the program. Because the instruction has 4 mini-steps, each mini-step takes one clock cycle (0.3 nanoseconds), and there are only three instructions in the program (DB isn't an instruction, it's encoded as just data with an address in machinecode), that means our program will execute in only 3.6 nanosecond. This is why computers can do calculations so quickly. In order to display graphics, the technique really depends on the type of display and how you communicate with it. In the old days, before fancy GPUs, the CPU would calculate what needs to be on the screen and the videocard would translate that into something that the screen can speak. In the normal RGBa colorspace that we've used for quite a while, the computer sees the display as a grid of pixels, with each pixel having 4 bytes of data, one for each of Red, Green, Blue, and Alpha (alpha means transparency). This is where we get the term RGB, and why RGB colors are 0-255 (the range of value available in 1 byte of data). I hope this answers your questions, and I'd be glad to answer any followups. I'm sure I might have gotten a few details wrong, so anyone else feel free to correct me as I'm still studying this stuff.",
"If I gave you a Plinko board and told you to get the chip into a specific spot, it’d be hard. But, if you could control whether the chip fell left or right when it hit a pin, you could choose where it went. With this new setup, you could pass enough chips through and start stacking them up that you could spell your name. Thus, with many simple chips going through many simple gates, you can create a message. The computer does this on a much larger, far more complex, and much faster scale. Different components, like your monitor, will receive some of those messages and decode it, turning on/off pixels in the process.",
"If you really want a \"like I'm five\" answer, explaining everything from the ground up, the book you should read is \"Code\" by Charles Petzold. This book starts with the absolute basics of binary and switch-based logic circuits. By the end, it has shown in detail how to build a simple CPU, roughly the sophistication of the Intel 8080. And after that it explains the basics of software.",
"At the most basic level, you've got a transistor. This is a device with three pins. If you apply a voltage to one of those pins, it permits current to flow between the other two. If you take away the voltage, current will no longer flow. Now, imagine I have a pathway between high voltage and ground that passes through two of these transistors. If I look at the voltage before both transistors, it will either be equal to my high voltage or equal to ground depending on how I set the gates (control pin) of my transistors. If I set them both to 'open', then my output will be zero (equal to ground). If I set either to 'closed', then my output will be one (equal to high voltage). This is what is known as a 'NAND gate'. It performs the inverse of the logical operation AND. As it turns out, you can use NAND gates to simulate any other logical gate - AND, OR, NOT, etc. - by combining them in various ways. So now we can perform any basic logical operation. But if we can perform any basic logical operation, that also means we can perform any basic *arithmetic* operation. It also means we can build devices called 'flip flops' where we use logical gates feeding back into one another. This permits us to have outputs based on past inputs, or memory. Since we now have mathematical operations and memory, all we need to do is route our outputs to an array of LED to display our outputs. Since we've got those transistors, we can re-route signals easily - just like a switching tracks for a train. All you have to do at this point is scale it up to staggeringly complex levels.",
"Ben Eater has an absolutely amazing series of YouTube videos that walk you through building a computer from fundamental components on bread boards. You'll learn how everything works at the lowest levels. URL_0",
"Your computer has a processor that takes instructions in the form of binary and passes it to an electric circuit that runs the same way if you plug in the same pattern. It also has memory. Static memory can be thought of as electricity running in a certain loop pattern, and we set that to 1 or 0 to remember things. Computer circuits, besides memory, always respond deterministically. I like to think of it like a vertical maze with holes for incoming electron rocks on the top, and holes for output electrons in the bottom. Only gravity and the maze guides their path, therefore they're deterministic and will always fall in the same way if you place them the same. Imagine a simple calculator that adds numbers. It has a bunch of wires for the first and second numbers going in, and others going out for the answer. We can group a few wires together to make numbers. Like if a wire can only be 0 or 1, two wires can be 00 (0), 01 (1), 10 (2), 11 (3). The idea is to figure out this maze such that 1+2=3. Digital logic is the discipline we use to make sense of building those mazes. In the end, your computer just takes a bunch of 0's (an electron!) and 1's (no electron!) and just throws them into the right mazes to give you desired output like lit! (1) and not lit! (0), etc."
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|
[
"url"
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[
"url"
] |
gp38xw
|
How can a CPU handle workloads better but still have lower fps than another CPU?
|
I saw a meme about it and I just got really confused - if it's faster at completing tasks, shouldn't it deliver higher frames? Sorry for my spotty PC knowledge. I'd appreciate any help!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frji636"
],
"text": [
"Most games are not optimised for parallel processing/multi threading very well so they benefit from higher clock speed more that high CPU core count. Workloads that are multithreaded optimised will better utilise high core count CPUs without huge regard for clock speed. Intels 9900K vs the Ryzen 9 3950x would be a good example."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gp56x8
|
Why is there such a difference in mirror appearance and photo/selfie appearance?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frjsl53",
"frjw9hw",
"frjw60c",
"frjy0ao",
"frjzqmg",
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"In your mirror your image is flipped horizontally. That is how you most often see yourself and that is how you expect yourself to look. Selfie cameras show your image not flipped, how everyone else sees you. Since all faces are somewhat asymmetrical, this looks subtly off to you and that feeling usually makes you not like it. But your selfie looks normal to everyone else. Also selfie cameras tend to be pretty wide angle and held fairly close to the face which is not an attractive way to photograph someone.",
"The short distance will make your nose big and your face deformed. To allow photos that capture your entire face, you'll need a wide lens in this case. If you want a nice portrait, ask a friend who has a decent camera and a 125-300mm lens. This will also force the photographer to use a larger distance and your face will look more natural. If you are a man and want to look handsome, squint your eyes while taking photo. Seriously, try it. Edit: Technically it's the short distance that distorts your face. I associated it with a wide lens because it's needed to capture objects that are near and quite large. Thanks u/Andre_Lac.",
"The mirror is flat, the lens is round. This creates distortion. You look at the mirror and see an over 16K resolution. Your phone creates a possibly interpolated 4K version with pixellation, compression artifacts, banding, and other digital anomalies. The light is steady when looking in the mirror. Selfies depend on steady hands. The angle is dead on in the mirror. The selfie depends on the angle. The mirror is distant enough for you to take everything in. The phone is arms length. Mirrors allow your eyes to focus. Phones try to focus accurately but are not as good as your eyes. Your eyes handle imagery (with help from your brain.) Your phone depends on lens, algorithms, settings and processing speeds.",
"How do other people see us then? As we look in the mirror albeit mirrored or as we see ourselves on selfies?",
"when people answer that my selfie picture is what people are seeing I seriously want to murder myself. I look like a creature on selfie cam and I look good in the mirror. 2 different fucking people.",
"URL_0 Your eyes have a different focal length than the camera on your phone.",
"There's a reason that back in the day when people went to a professional to get photographs of themselves, it'd be done with something in an 85-135mm lens range. Moderate telephotos tend to \"squeeze\" while normal and wide angles tend to \"pull\" - so longer lenses will give more flattering results for people. Selfie, and phone cameras in general, tend to be fairly wide angle and as a result tend to make you look \"wider\" than you actually are. It's called barrel distortion - because the shape of the distortion is similar to that of a barrel where it widens in the center."
],
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|
[
"url"
] |
[
"url"
] |
|
gp5yvz
|
For cameras, when you slow a video down, you see frames; you zoom in and see pixels. For audio, is there an equivalent? Can one mic make more data points than another and can each data point be of higher/lower quality compared to other mics?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frjxwmx"
],
"text": [
"The equivalent of a pixel in digital audio is a sample. This is a measurement of the pressure change at a given time. The highest frequency you can accurately represent is half the sample frequency. And similar to pixels an audio sample can also have varying number of bits representing it. A high bit rate will allow you to represent lower volume sounds similar to how a higher bit color bit rate in a video will allow you to see darker things. The sampling does not happen in the microphone. The microphone is just measuring the pressure changes in the air and converts it to electrical signals, still analog. There are things in the microphone and the cables which distorts the signal and different microphones can give different frequency response. But all of this is before the signals have been digitized, similar to how the lens of a camera can change the quality of the image. The sampling of the audio happens in the Analog to Digital Converter. This is where the sample rate and bit rate gets set."
],
"score": [
14
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
gp6jlj
|
How do green screens work?
|
1. Why only green?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frk19ue",
"frk4bh9"
],
"text": [
"In a nutshell, you bring your green screen footage in and tell the computer to ignore any pixels that are green, leaving behind whatever else is in the shot. Generally any process that involves using colour information to separate objects in a frame is called Keying, with this in particular being Chroma (so... colour) Keying in specific to differentiate it from using something else like Luma (brightness) to do the same. Its not only green, blue screens have their place as well. But Green is the most commonly used colour for Chroma Keying for two reasons. The first is that the way digital cameras capture light biases toward greater accuracy in the green channel, [there are literally more green photosensors]( URL_0 ) in digital cameras which makes it an optimal colour to use. Second is that the things you put in front of a green screen, typically people and their clothes, are usually not green or any shade of it (unlike red which would conflict with skin tones or blue with common clothing), so theres less work involved in the Keying process.",
"Blue/green screens work by telling the computer “See all that green? Remove it and replace it with whatever I want to put behind it”. Basically, the green/blue screen is lit properly, to make it a uniform colour (this makes the computer’s job easier and makes it more likely to go smoothly). Then, the scene is shot, and after that, the footage is put through editing software. You can select the colour and then that colour can be replaced with whatever you want to go behind it. In the olden days it was a little more complicated but functionally worked the same. Blue and green are used because clothing and people generally aren’t blue or green; if a colour is used for a character then the opposite screen will be used. As an aside, in the Original Trilogy of Star Wars, you can tell when R2-D2 was being filmed on a blue screen, like in the final shot of Empire Strikes Back, as he suddenly starts sporting black stripes as opposed to blue stripes; an artefact of the blue screen."
],
"score": [
15,
3
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Bayer_filter"
],
[]
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}
|
[
"url"
] |
[
"url"
] |
gp7rdw
|
VPNs. What are they? Are they Legal? Are they free to use? Are they completely secure too?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frk9hbl"
],
"text": [
"> ELI5: VPNs. What are they? Ever thought of using somebody else's computer to check on something that might raise suspicion at home? Eg, you want to download some porn, but your parents would really frown on that. So you go to a friend's house instead, because their parents wouldn't notice or care, and this way you leave no traces of what you were doing where your parents could be watching. Well, VPNs are sort of like that. You're connecting through somebody else's internet connection. This often gets used for remote work, when you want to work as if you were present at the office. Or, you can buy such a service from providers who sell it for the purpose of making your connection go through another country entirely, so that your ISP and/or government doesn't know what you were up to. > Are they Legal? Depends on the country. > Are they free to use? Depends. Your workplace might give you one for free. But in general you pay for them. You'd best not do anything weird with your work-provided one, too. It's almost certain to be monitored. > Are they completely secure too? You're sending all your internet traffic through somebody else's computer. Which means you're changing who can keep an eye on you. Say, in the above example, you escape your parents' oversight, but place yourself under your friend's parents' oversight instead. It's up to you to decide whether that works out favorably or not. Generally, unless you're doing something illegal, it's unlikely any VPN provider would have any interest in your porn tastes, which is a great improvement if your government is. VPN providers that offer them for privacy reasons generally promise that they set things up in such a way that your usage doesn't leave any traces on their system, and that they couldn't tell the police what you were doing if they came knocking. This is generally in their interest, because nobody would pay a provider that was too friendly with law enforcement. However, this might be a lie, their setup might not be as good as they think it is, and their local government might be able to force their hand."
],
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8
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|
[
"url"
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[
"url"
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|
gp8l2l
|
why did CRT TVs leave a small dot in the middle of the screen when they were turned off.
|
Title. Like what was happening?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frkdaz6"
],
"text": [
"CRTs make pictures by shooting a little beam of stuff at the screen, basically little bullets of energy. When it hits the screen, chemicals on the screen light up. Unfortunately we can't move the little gun that shoots this stuff. But what we figured out is we can use magnets to move the \"bullets\" around so they hit all of the screen and make it all light up. When you turn off the TV, these magnets also get turned off, but the gun keeps shooting for a bit. Since there's no magnets to move the bullets around they just hit the center of the screen"
],
"score": [
14
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
gpbwgx
|
Why did so many computers use “control alt delete” to “unlock,” was there a reason?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frkxxd7",
"frky8u3",
"frkxzve"
],
"text": [
"Ctrl-Alt-Delete is a special set of keys that Windows doesn't pass through to programs on the other side which makes it a bit more secure and very unlikely to happen accidentally When you press keys on your keyboard they get handed to the motherboard which passes them off to the OS which then gives them to the focused program. Except Ctrl-Alt-Delete, when Windows sees that 3 key command come in it just snags it for itself and doesn't pass it along. This also protects you against programs that may create a fake windows Login screen as pressing Ctrl-Alt-Delete will bring up real Task Manager and hopefully make you realize that login screen isn't a real one.",
"Yes, actually! A while ago, back when Windows NT was the dominant operating system, malicious actors would install a fake login screen that would capture people's usernames and passwords when they went to log in. The ctrl-alt-delete key combination is something called a \"secure attention sequence,\" which can't be intercepted by a running application and goes straight to the operating system. By using that key sequence, the user would know that it was actually Windows receiving the username and password, and not anything else.",
"The key combination is a unique signal to interupt the operating system, it can only come from a keyboard, for security reasons, you wouldn't want the signal to be able to come from other inputs like a network, program or device. Only the user can do that from the keyboard"
],
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9,
4
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|
[
"url"
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[
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|
gpgg2n
|
How does a pacemaker work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frlznb2"
],
"text": [
"Your heart has a little battery connected to it called a neuron. This battery sends itty bitty electrical shocks to the muscles in the heart to get the muscles to work in the right order. A pacemaker is a second battery that watches the heart’s battery. If the pacemaker sees the heart’s battery not working right, it kicks in to get the hearts battery back on track."
],
"score": [
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|
[
"url"
] |
[
"url"
] |
|
gpk5vx
|
How are we able to take photos of astronomical objects that are so far away and so large?
|
I have very little knowledge of space in general. I saw [this]( URL_0 ) post on r/space, and saw that just a small portion of the photo was labelled to be 5 light years long. That got me thinking, how does the technology that allows us to take photos of things so ridiculously large and far away from us even work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frme5qx",
"frn24m9"
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"text": [
"Really, and I can't stress this enough, really large telescope mirror for a camera. URL_0 Video shows how they made 1 mirror for a three mirror setup.",
"How long an object is irrelvant. When there is a full moon put up your arm and stick up your thumb and are approximately as wide as your thumb. The moon is 3,474km in diameter but looks as large as you tumb. As long as the object is large enough in you field of view and emit enough you can see it. The moon not harder to see then your finger even if it is a lot larger. Far away is not a problem if the object is bright enough. The closes star excluding out sun is 4.6 light-years away. Of the 300 brightest stars in the sky the median distance is 185 light-years, 19 of them are farther away from the 1000 light-years. So you can see start far away with your naked eye. As long as they are bright enough it work fine. Stars are small compared to the distance so they are just points of light but clearly visible. How large an object look in your field of view is called the angular size. The moon and your thumb on an extended arm have a similar angular size. How hard they are to see just depends on the amount of light from them that hit your eye. You can see your thumb in a dark room so the light requirement is clear. The angular size is the with/distance as if the ratio is constant object look the same size in you vision. So if an object is enormous is can be very far away You can see the Milky Way in the sky that is the core of our galaxy, the center is around 25000 lightyears away. So you can see the total light of millions of start spread out for thousands of lightyears with your own eyes covering a large part of the sky. So an enormous size is not a problem at all, angular size can be a problem if it is too small The farthest object you can see with your naked eye is the Andromeda Galaxy 2.5 million light-years away. It will be a fuzzy white area in the sky where you see the brightest core part that might 50 000 light-years wide. The Andromeda Galaxy is enormous in the sky but is quite faint so you need a telescope to collect a log of longer. This is the [Andromeda Galaxy and the moon]( URL_0 ) to scale in the set. It is made up of a trillion start so you can see them individually. The Pillars of Creation you linked to is part of the Eagle Nebula 6500-7000 light year away. So the 5 light-years wide object will look quite small at that distance. So is large and far away but surprisingly large in the sky The angular size would be 5/7000= 0.00071 radians or 0.04 degrees. The angular resolution of a human eye is 0.02 degrees so you could in fact see the Pillars of Creation as larger then a single spot if the was bright enough. A basketball is 9.5 inches (24.1 cm) so the Pillars of Creation would look as large as a basketball that is 9.5/0.00071=13380inches = 1115 feet = 0.2 miles away from you or simpler 0.241/0.00071=339 meter. I think you would the basketball very well with good binoculars. The problem is seeing the Pillars of Creation is not the size but the fact that the amount of light you get from them is low so you need a large telescope that collects a lot of light for a long time to get an image."
],
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"text_urls": [
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[
"https://apod.nasa.gov/apod/image/0612/m31abtpmoon.jpg"
]
]
}
|
[
"url"
] |
[
"url"
] |
gpkrww
|
What enables satellites in space to not bump into each other, seeing that there's so many of them up there?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
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"It's mostly that they are so far apart, but having information on their orbits helps quite a bit, similar to being a flight controller at a large airport, if you're a space agency you would keep track of the orbits of your satellites, and keep them somewhat apart just to be sure. The collision problem is actually something that you will encounter, just with junk. Literal space junk. Space missions leave behind trash and it has started to accumulate. We actually can't track all the junk in orbit, because there are tiny particles involved in this, as small as one centimeter across. However, because they are going thousands of meters per second, they act like a bullet on impact. They also crash into each other, further shattering and forming more space junk parts. And sometimes, collisions with space stations or satellites happen. (If you wanna look up more, this problem is known as Kessler Syndrome.) Sorry, went on bit of a tangent, but TL;DR: Satellites aren't your worry, space junk is.",
"\"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space.\" - Douglas Addams",
"Google tells me there are 2218 artificial satellites currently in orbit. Imagine the Earth is entirely made of land and that there are 2218 people on it, walking around it in a straight line. What are the odds that you bump into any of them? Pretty slim. That's kinda the situation for satellites, except you have an added axis of movement away from the surface - so even more space to occupy. Nonetheless, we do have very accurate data on the orbits of all those satellites, and can easily predict of any are going to come anywhere near eachother.",
"There are a few thousand satellites, but Earth is really really big and satellites aren't just in all sorts of different locations, they're at different altitudes too. The chances of collision are just really small. In comparison, there are around 20,000 airplanes in the sky right now, but how often have you ever seen two airplanes near each other, anywhere other than an airport? Airplanes almost never encounter other air traffic when they're not near an airport. There are fewer satellites, they're much higher and much more spread out, and they don't cluster near things like airports, they just orbit.",
"They're really really really far apart from each other. And the most crowded orbits near the earth are the ones most subjected to atmospheric drag; the satellites are planned to fall back to earth eventually."
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[
"url"
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[
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|
gpolc1
|
Why is the time estimated on computer installation/download/repairs etc. ALWAYS wrong?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Downloads are actually pretty good to predict (as long as the connection is somewhat stable) because what the program is doing is fairly uniform: Download some chunk of data, write it to the disk. Once you've done that a few times and you know how big the actual file is (i. e. how many more times you have to repeat that process until you're done) you can predict pretty well how much longer it's gonna take. You just take the average of the last x cycles and multiply it with the number of cycles left. The problem starts when you have to do very different things in one process that to the user looks like one process. Let's say I'm installing a game (to the user one process). But at the working level that involves multiple steps with completely different properties. One subprocess of that is downloading the packed archives from some server. (Quite easy to mesaure, as I just talked about). But the next step is uncompressing those to the disk. How does that compare to downloading? Hard to say upfront. Downloading depends practically only on download speed and disk write speed. Unzipping depends on how fast the CPU is, how much CPU time is consumed by other processes and how fast the disk can read *and* write. Were we capped by the download speed before? Can the disk actually write much faster? How does the disk read speed compare to the write speed? Will some anti virus guard delay our write calls per file? We don't know yet. Notice that the uncompressing part by itself can again be predicted okayish as well. But only once we started it. Worse than downloading an archive, because depending on the file sizes in that archive the OS might handle writing very unpredictably. But still okayish. You can uncompress say 50 MB three times, check how long that took on average and again multiply that with the rest of 50MB chunks left. After that you have to create some registry entries and/or shortcuts in some folders. Now that's some completely different calls to the OS again. How long do those take? Might not even be consistent over several patches of the same OS. Let alone different versions of it. Or god forbid we have multi-platform support. So we have Windows 7 vs. Windows 10 vs. Mac OS vs. whatever powers a Playstation. (Actually now I'm a little curious). So to sum up: The individual steps needed - when they are quite uniform - can be estimated pretty well **once you've done some part of them**. Thats also why you often see different progress bars for individual steps. Or at least status messages of what step we're currently in. That's the best info we have at that point in time. What's hard is bringing them together upfront, especially with data that is unknown at the start of the whole process. The best you can do are rough estimations with a lot of assumptions about the computer this process will be running on. I mean you could totally measure most of it with \"test download, \"test unzip\", \"test xy\" before the actual process takes place and that would improve the upfront estimation siginificantly. But at some point the effort and software complexity is just ridiculous compared to a slightly more accurate progress bar. Also I'm not sure how happy users would be if they found out we actually added two minutes to their installation process doing pointless downloading and unzipping. Just to measure their system in order to improve estimation accuracy. I believe in the end people prefer if it get's actually done as fast as possible. But I admit is **is** kinda annoying when the first 60% take 5 minutes, the next 30% 8 minutes and then the last 10 go through in a minute.",
"Your processor has many applications that want its time. To give you the illusion they're ALL running at once it quickly swaps between them. So, when the application in question is briefly running and asks itself \"when might I be done?\" it has to guess; it's at the mercy of the operating systems scheduler. So just like a download is at the mercy of the wild West which is the internet, so too are your local applications - as there's often hundreds always running in the background, each of which could spring into action at any time.",
"when an install or download starts the estimated time is based on data transfer. As a connection is made the estimation starts, however it is only transfer small files so it may take a snippet of a second then have to find a new space for the next file to begin. Each time it has to find a new slot there is no data transferring, that is why it estimates a long time. As it reaches the main files these are normally larger and data transfer remains high for longer time and the estimate changes and becomes more accurate. As it closes out the install it also does some small files which again need to have space found and to be transfered each time making the estimate different again even though It may have 5kb left that 5kb might be 100 text files that all need to be place so instead of taking a fraction of a second, could take 1 or 2. Installs and downloads rely on the hard disc write speed(fragmentation also affects this) as well as data transfer speeds. Downloads can also fluctuate because of changing sources but are generally closer in estimation because there is often less smaller files to transfer. When writing to a disc it needs to a:find where to write something b:write something there c:write where it closes d:note where to find it again. This is why those little files take longer than they would seem they should and as these files in installs are all through it that is why the estimated is wrong. Eg a game may have 1000 tiny files for programming and stuff and 10 large files for video audio and game data etc.",
"In addition to the actual explanations, I'd like to offer this one: the psychological effect of a progress bar is to show that progress is being made, so that you wouldn't be wondering if it's still running or not. Giving an accurate estimation of how long it will take is probably very difficult or impossible in most cases because many things can influence computing performance, and might not be worth the effort.",
"The reason it's not accurate is that the estimates and percentages are a way to tell you that it's still installing and not stuck. They were never meant to be precise. And downloads are simply based on the remaining size to download divided by throughput of the transfer.",
"Maybe an actual eli5: Imagine you have a huge shopping list where you have to go to several stores to pick stuff up. But your mom asks you to give you an estimate when you will be done with it. So, you kinda go from memory how quickly you can get through the aisles and checkout. You tell your mom \"20 minutes Walmart, 15 minutes Bath & Beyond, 5 minutes Trader Joe's. So 45 minutes total\". Now you actually go shopping ... and there's a huge covid line in front of Bath & Beyond. Ugh, that added 5 minutes. Luckily though the items in Walmart had been moved closer to the cash register, so you actually got out that place quicker. That's the problem software engineers have. You try to estimate how long it will take based on previous installations. But, maybe your computer has a really slow hard drive. Well, there goes that estimate of the software engineer. Or maybe one component was already installed! Then the bar can jump forward.",
"The time estimate can go wrong in various ways. In the first place, an application cannot know what other applications on the computer are doing. Imagine you are installing new software. The installer knows it has to copy 2 gigs of data to the disk. After 5 seconds have passed, it sees it has copied 512mb of data, so it estimates the job is 25% done. But suddenly your email reader activates and decides to download a ton of emails. Now both the installer and the email reader are competing for access to the hard drive. So the installer has to slow down. There's no way it could have predicted this. Even when nothing *apparently* changes (like email activating), this kind of interruption can happen. The operating system (Windows, Mac OS, Android etc) has complex scheduling algorithms to decide which programs get priority to access resources like disks, network traffic, memory, etc. Individual programs can't easily predict when the operating system might decide to prioritize or neglect them. In fact, this problem is so pervasive and tricky that if you really need to accurately predict the time a process will take - for things like industrial robots or military hardware (reacting to a missile on radar e.g.), specialized 'real-time' operating systems and programming languages are required.",
"It's just like a roadtrip to grandma's house. When you start, you ask your parents how long it will take. \"Well, according to distance, it should take 3 hours\", they say. (Computer looks at what needs to be done and how fast it should go. Gives you its best estimate) Quickly after you all drive off, your parents decide to go a bit below the speed limit. \"More like 3 hours and a half\", they say. (Power management settings prevent your computer from going 'full speed') After a few minutes, you hit a big trafic jam. \"More like 5 hours\", they say. (You start playing a game. This 'clogs' the computer as it can't do everything at once) The trafic jam miraculously gives way and the car goes up to the speed limit. \"Only 2 hours left!\", they say. (You close the game and remove the power management restrictions) You and your siblings start fighting. Your parents have to pull over to manage the situation. \"Still 2 hours left since we had to stop\", they say. (Internet connection throws a fit, computer has to 'pause' while waiting for the next files to download) I could go on, but by now you should see the point. Your computer keeps changing the amount of time left because the situation keeps changing. The time goes up if the car has to slow down for whatever reason (you start watching a movie, playing a game or the computer downloads a system update for example). The time goes down as the car gets back up to cruise speed.",
"1. **The amount of work to do isn't always known.** Imagine you ask somebody how long it will take to install an in ground swimming pool in your home. Once they start digging, they find that there is a huge granite deposit under your lawn with a cavern underneath. Even if they still install that swimming pool, they may have a ton more tasks to do to dig and then make a solid foundation. 2. **The one performing the work isn't always privy to all of the things that may factor in how it is prioritized. / The rate of work depends on outside factors.** Imagine you are working on a marketing campaign for a client who asks for an informal estimate of how long it will take, after you give that estimate your boss tells you to drop everything because a major client is having a disaster and needs priority. Your first estimate didn't factor that in so, it'll be way off (or it did and you'd be way off if your boss hadn't said that.) 3. **Better estimates waste time that could be spent doing the job.** Imagine you are asked to estimate how long it takes to drive from Cincinnati to Chicago (without tools like Google maps or a GPS that does it for you). If you just eyeball the physical distance (not road distance), you could come up with a rough estimate almost immediately but it may be way off. Other other extreme, you could measure out the exact roads you'd travel on a map cm by cm, multiple those distances by the speed limit of those roads, look up historical traffic, etc. You'd end up with a really good estimate but it would take a while to put together and all that time you wouldn't be driving."
],
"score": [
946,
459,
45,
40,
13,
7,
4,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gpoqq5
|
Grind in games
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frnkmr6",
"frnjg11"
],
"text": [
"There is a strong correlation between hrs played and money spent on games so game companies are trying to create gameplay loops that keep you playing. Grind is part of that. Where this gets messed up is creating bad loops. Habe you ever played a game and they r like, ok you need to collect 99 more feathers and ur like...no...i dont want to...and shut the game off? That is a bad loop.",
"I think that a lot of the reason for grinds in video games is the send of accomplishment that comes with the reward at the end. Being able to show off your new skin or weapon after 10 hours of grind is a satisfying feeling for a lot of people."
],
"score": [
14,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gpq5ug
|
How can Microsoft release one updates for Windows 10 and all devices get it while only few devices get Android updates?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frnxrda",
"fro1hp7"
],
"text": [
"Windows 10 is Windows 10, but since Android is open source, every phone manufacturer home brews its own version. When Google puts out a new Android release, it goes to all eligible Google-manifactured devices, but Samsung, Sony, HTC, etc all have to modify it before allowing their devices to install it.",
"1. First, all the manufacturers customize Android for their particular phone. 2. Then they further customize it for every variation of that phone (Galaxy Note with a Samsung Exynos CPU vs Galaxy Note with a Qualcomm Snapdragon CPU) 3. Then, (sometimes) mobile service providers put some more customization on top of that (this has been a decreasing trend) Because of the numbers of phones and the variations of phones, it takes a lot of effort and testing to pump out updates - they're better off making you want to upgrade, so they kill off updates rather quickly. Apple, makes very few products and has total control from start to end in both hardware and software, which is why their products are supported longer. Windows is much bigger than a mobile operating system could hope to be (currently) so they can include more hardware support out of the box, availability of drivers from manufacturers also helps, localisation etc. The x86/x86-64 platform is also very stable and mature, while custom ARM chips are more fragmented (they add different proprietary stuff in their custom chips) which requires more work when developing low level software (issue 2)."
],
"score": [
10,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gps7wr
|
How do the different computer languages work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frodwsp"
],
"text": [
"The computer is basically full of things that act like switches and can be turned on or off. When you write your code, the second you touch the keyboard or mouse, you flip some of these milloins and millions of switches. This is computer memory. The display of your computer has been built in such a way that it can constantly read how the switches have been flipped and make a picture depending on what it reads. When you run your code, it is taken from the computer's memory and a special part of your computer's software turns it into what's called machine code. The exact way this happens depends on the programming language you use. A bit like your display has been built to read the memory, your computer also has a processor that is built to read the machine code. Based on the machine code, it again flips specific switches in the memory and that makes things happen."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gpsnjc
|
I've read that Earth is overdue for a reversal of its magnetic fields. If this occurs, how would it impact our everyday lives?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frogfts"
],
"text": [
"The poles do reverse every so often but they don't flip in an instant the poles weaken and migrate slowly to the other location. This will effect migrating animals like birds which use magnetism to navigate, however most of it will have little daily effect. The problem comes when the \"pole\" is overhead as it migrates when there will be little protection from the rays from the Sun. URL_0"
],
"score": [
9
],
"text_urls": [
[
"https://youtu.be/QGTPr3CG6GA"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gptuum
|
How do file archivers work?
|
What happens, besides compression, when computer files are put in an archive such as zip, rar, tar, etc?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frqfl7e"
],
"text": [
"Archiving is nothing more than concatenating binary file contents together into one big blob, and keeping an index of where each file starts and ends in the blob. So if file 1 is 0011001 and file 2 is 101101011001 then the contents of your archive file is 0011001101101011001, with an index that says \"file 1: bits 1 to 7; file 2: bits 8 to 19\". The type of compression can change this though, some formats can combine compression across multiple files. So if your archive had 2 text files with the same content, then not only could it compress the first text file, but it would realise the second file contains the same patterns of data and re-use them. Effectively that second text file takes no extra space. The index would then refer to the same blocks of compressed data twice in order to reconstruct both files. Compressed archives don't always use this method though, because it can mean an incomplete/corrupt archive potentially loses all of the files. Whereas if you compress each file separately, an incomplete/corrupt archive means only some of the files are lost."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gputlq
|
why do photos look better on the screen of the device you took them with (smartphone, camera, etc.) than when you look at them on a laptop or PC?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"froxut6",
"frov2aj"
],
"text": [
"Part of it is the pointless \"Megapixel Wars\". Cameras are tricky things, miniature phone cameras doubly so. Consumers don't want to hear about focal length, ISO, contrast ratio, dynamic range, universal vs rolling shutter and many more technical details that make a camera \"good\" or \"bad\". So, digital cameras have overwhelmingly been marketed by how many \"megapixels\" they have, that is, how many millions of tiny light senors there are in the camera. Theoretically, more sensors=better, higher resolution image. In practice though, the tiny lens placed way too close to the sensor in most phone cameras limits them way more than the sensor does. So, you have a high-resolution, perfectly crisp representation of an inherently blurry image. If you ever view phone camera photos at full resolution, they look awful. But, if you view them at 1/2 or 1/4 scale, they look ok, because that's about as sharp as the optics allow for. This is a result of building a sensor with way more \"megapixels\" than is really needed to capture the best possible result of the bad, miniaturized optics. And nobody cares because nobody who is taking a quick selfie is concerned that it only looks good on a small screen, and nobody who wants professional results is using a phone camera.",
"Yes, you have what I would say 3/4 right, the last fourth would be down to phone screens usually oversaturates pictures (more colour and higher contrasts) which the human eye for some reason finds good looking. And usually does computer monitors try to stay as true as possible to the correct colour or in the case of bad monitors, undersaturares the image and hides colours."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gpvb7o
|
how does a electric Microphone work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"froy9gz",
"frpad0w"
],
"text": [
"Microphones and speakers are basically the same thing. Sound waves push and pull on a mechanical layer. Those movements are converted to electrical signals thanks to a magnet on the microphone and passed to a computer for processing. Obviously, Microphones are optimized to receive sounds while speakers are optimized to play them",
"There are two different types of microphones that are common today: dynamic and condenser microphones. While they have slightly different mechanisms, they work on the same principal. Sound waves are variations of pressure in the air. Microphones contain a very thin membrane called a *diaphragm.* They are thin enough that the pressure changes of the air will cause the diaphragm to move back and forth with the pressure changes. In a dynamic microphone, there is a permanent magnet fixed in place. In front of that magnet is the diaphragm, which also has a small copper coil attached to it. When the diaphragm is pushed back and forth, it moves the coil in the magnet's field (this is called *magnetic induction*). This creates an electrical voltage in the coil, which we can amplify or record with other equipment. A condenser microphone works off the principal of *capacitance*. The diaphragm in this type of microphone has a thin layer of conductive material, like gold, coating it. The diaphragm is placed close to, but not touching another conductive plate. A voltage (conventionally 48V) is applied to the diaphragm, creating an electrical device called a capacitor. As the sound waves move the diaphragm, the distance between the two surfaces changes. As this distance changes, the amount of power that can cross the capacitor also changes. These power changes represent the sound that is coming in, so we can record them or amplify them, like with a dynamic microphone."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gq3fjj
|
How are video games ported from one console to another without having to completely remake the game?
|
I imagine some complex piece of software responsible for porting assets. But how is porting really done?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frr1719",
"frquh5q"
],
"text": [
"Layers of abstraction. When you develop any kind of software, you very rarely need to develop close to the actual hardware - mostly because you don't often even know what hardware you're running the software on. If you think you should play the sound, you don't write code that says \"find out which of the sound chips I know how to operate is attached to the computer and then send this audio data for playback accordingly\" - you say \"hey, operating system, I'd like to play back this audio data\" and operating system says \"leave it up to me, I know how to talk to the sound chip, and which particular output device the user has chosen right now, bet you don't know or care\". So a lot of games are based on *as little platform-specific code as possible*. And as far as video game developers are concerned, they don't usually need to even care all that much about the console hardware because the engine they're developing the game on was already highly optimised for the consoles in question by the people who made the engine. In addition to that, usually the engines that were made in transitional period between console generations have support for both old and new consoles, so in the simplest case the porting would be as simple as \"hey, let's just set the build target for a new console and rebuild.\" (...it's never that easy in practice, but hey.)",
"The game is ALWAYS made and coded and designed and EVERYTHING done on a pc, they just port it over to a console and optimize it and design it according to a console, so it's very easy to carry it over to a pc they just need to adjust the graphics optimization and the control scheme and voila"
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gq3phw
|
What is the least significant bit when it relates to steganography and how does it help find the encrypted information?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frqixx1"
],
"text": [
"Steganography is a way to hide information in images. In a digital image file, one way to do this is to make small changes that won't easily be noticed when viewing the image. Let's say that an image file contains three numbers for every pixel in the image - Red, Green, and Blue. Those numbers tell you the intensity of each color. If you want to make the hidden information not mess up the appearance of the image, you want to make only small changes to some of those RGB numbers. Let's say that the RGB numbers for a pixel are 123, 56, and 200 (decimal). For R, the most significant digit is 1 (representing 100) and the least significant digit is 3 (representing 3). You wouldn't want to change the most significant digit, as that would have a huge impact on that pixel's color. But changing the 3 to a 2 or 4 would be so small that it likely wouldn't be noticeable."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gq5df5
|
Why AES encryption is the standerd
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frqs4bx"
],
"text": [
"Because it was specifically designed and chosen to be the standard. Since 1977, the encryption algorithm called DES (Data Encryption Standard) was used, but by the 1990s it became increasingly weaker (as computers grew more powerful), so NIST (National Institute of Standards and Technology of the USA) decided to replace it with a more advanced algorithm, which would be called AES (Advanced Encryption Standard). They started a three year long process from 1997 to 2000, during which multiple algorithms were presented and reviewed, until they agreed on Rijndael. It was chosen because it was strong cryptographically and easy to implement efficiently."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gq6p5u
|
How does the internet work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frqz9vl"
],
"text": [
"Basically it's a giant network of devices connected, identified by an IP number for the other networks, and a MAC direction for the same network devices, also, every device has a route table to choose what's the next jump avaliable to send the messages for reaching the destination. This is a ultra simplified, there are a bunch of devices that act in different ways and protocols that has their use, for example there are protocols for getting the IP of a web, protocols depending on the type of network you are, dynamic protocols for updating the route tables, and a long etc"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqcqvh
|
How do they send data back from far outer space?
|
my wifi can't even reach my bedroom
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frrxgsv",
"frrybd7",
"frrxqsb"
],
"text": [
"Your wifi router has a small antenna, probably no more than 10cm long. Your phone's wifi antenna is even smaller. There's also a lot of interference from hundreds of other devices that are also using wifi. Meanwhile, deep space probes are listened to by huge antennas, several meters wide, and they operate on frequencies that have little interference.",
"The antennas on satellites are what we call \"high gain\" antennas. Unlike a terrestrial AM or FM radio station which sends its signal out in a nearly 360 degree pattern, a high gain antenna focuses the signal so more energy is radiated to a particular direction in space. These antennas are pointed toward earth so that more of radiated signal is beamed toward us. Also, on the receiving end, NASA, ESA, etc. have high-gain receiving antennas which are pointed toward the satellites in space. Because they are high gain antennas, radio signals that they pick up are essentially amplified, but they generally only pick up signals which originate from the direction that they're pointed in. Signals which come in from the side or rear don't get amplified. They also use frequencies which are not generally used in terrestrial operations so there is less interference.",
"Your home wifi is limited by regulation to a very narrow band and very low power so that it does not interfere with other wifi transmitters in the area. You do not have to see further then to cell phones before you get much better range because cell phone operators will work together so neighboring towers and phones do not interfere with each. But in addition to being able to transmit on what frequency band they want at what power they want they also install huge antennas. While your wifi access point have a tiny 6 cm long whip the deep space network uses up to 70 meter wide parabolic antennas. This not only allows them to collect a lot of energy from the signal but also allows them to point it in a single direction. The space probes are similarly using parabolic antennas although smaller in size so that they can concentrate all the signal energy to a narrow beam back to Earth. Another difference is that the bandwidth for deep space communication is much lower then your wifi bandwidth. This is because they transmit each bit for longer times giving the receiver a better chance at receiving it and also sends the same data multiple times so that if the receiver did not catch it correctly the first time they have a chance at getting it right the second time."
],
"score": [
13,
9,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gqdm91
|
- Subnet Mask
|
Hello, i know this question has been asked numerous times, but it never managed to truly explain it, and it's quite frustrating. So far i understand that a Subnet Mask is used to divide an internal IP address into a Network Portion and a Host Portion. I'll make the SOHO example because that's what i'm used to, never saw other networks. My internal IP is [192.168.1.1]( URL_2 ) and the subnet mask would then be [255.255.255.0]( URL_3 ). This would mean that only 254 hosts are possible in my network, right? Since the 1 is the Default Gateway and the last would be the Broadcast Domain. I still don't get the point in having a mask. It is my understanding that when forwarding a frame, the gateway would AND the 2 things: 11111111.11111111.11111111.00000000 & 11000000.10101000.00000001.00000001 the result would be 11000000.10101000.00000001.00000000 ([192.168.1.0]( URL_0 )) It's all fine and dandy but... i don't get why? Is this somewhat like an IF statement? e.g. IF the first 24 bits are 192.168.1, THEN it's inside this network? But why the extra mask then? Also because with that logic, all internal IP addresses would then become [192.168.1.0]( URL_0 ) & #x200B; The IP address range 192.168.1 is already private, why do i need another set of 32 bits for the subnet mask? 192.168.1 is already my inside network, so... it's obvious that 1 would be my default gateway, i would be 2 and so on... Is the subnet mask just a way to "make it obvious" to the router? I really don't get the sense of it, probably looking at it all wrong. Thanks in advance & #x200B; & #x200B; EDIT: Does it mean that in the routing table, my private IP is also associated to a subnet host? E.g. [255.255.255.4]( URL_1 )? Because running ipconfig i don't recall seeing my host address.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frs2shz"
],
"text": [
"I think what you're missing is the subnet mask isn't always 255.255.255.0 The subnet mask tells you which part of the address is considered local and which isn't. What if you wanted a subnetwork of only 8 addresses, with everything else treated as remote, and those 8 local? There'd be no way to really know this unless you specified a subnet mask of 255.255.255.248"
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gqj1uy
|
Why can’t you exchange some of your normal storage on a computer for more RAM?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frsyrxg",
"frsyo9l"
],
"text": [
"You can, and already do. It's called [paging]( URL_0 ). Your operating system will use disk space like extra RAM if it needs to, and will move less-frequently-accessed data from RAM onto the disk in some situations. You can configure the size of your page file to get 'extra RAM' -- and in the 90s there was scam software like SoftRAM that claimed to double your RAM by changing this setting. The problem is that disk storage is a *lot* slower. Anywhere from 1/10th to 1/150th of the speed depending on your disk and RAM type. So performance is much worse.",
"You can. This is called swapping. The disadvantage is that this additional memory will not be as fast as RAM but rather as slow as your hard drives. You may notice this as your applications will not immediately fail when you are out of memory but rather they will just slow down."
],
"score": [
18,
10
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Paging"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqjmfw
|
If humans can't see ultraviolet wavelengths of light, what is a blacklight?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frt473z",
"frt7x7z",
"frt2oyt",
"frt2nel",
"frt4olv",
"frtj034"
],
"text": [
"Florescent pigments absorb uv light that's invisible and then re-radiate some back at a lower frequency. That's why only some things glow in a blacklight. It's also how dayglo pignents work.",
"It’s called black light because they put a very dark blue pigment around the lamp, which looks black. This pigment blocks most visible light, letting only UV through, however it still lets some blue and violet through, which is why we can see it",
"You're right! A black light puts out *most,* but not *all,* of its radiation in the ultraviolet. In fact, if there's no filter material applied to the bulb to cut the visible light and give it the characteristic dim violet glow, a \"black\" light actually appears blue.",
"Fluorescent lights have a certain \"width\" in the emission spectrum. They don't emit photons of one certain wavelength, but a more or less broad \"peak\", with some photons at higher and some at lower wavelengths around it. The higher-wavelength flank of the peak of a blacklight reaches into the visible spectrum, making it look purple. But it's much brighter in the wave lengths you can't see, but ofc those don't add to the brightness for your eyes.",
"It's called a blacklight precisely because we can't see it. Oh sure, a portion of the UV radiation is down in the edge of the visible violet range, but that's just a small portion of what a blacklight emits.",
"You have probably heard that light can come in the form of infrared (heat), visible light (what we see, ROYGBIV) and ultraviolet (and more!). All light has something called a frequency. As a side note, radio waves are also a form of light. When we tune our radio to a station, we are listening to that frequency of radio waves. But back to the main point: Infrared is lower than visible light (infra-red - > below red), and visible light is lower than ultraviolet (ultra-violey - > above violet). The black light shines mostly ultraviolet, but it is not 100% perfect, and so it also shines some violet visible light. Because violet is the highest frequency of visible light, and so the closest to ultraviolet. This is just like how your stove top makes mostly infrared (heat), but it also makes some red visible light. Because red is the closest visible light to infrared."
],
"score": [
1122,
65,
55,
14,
5,
4
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqkw4q
|
How does Akinator actually do the thing?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frtao23",
"frtau2n",
"frtb31y",
"frtfr07"
],
"text": [
"By having a very large database with things/people/animals and their properties. Then it just ask about random properties and if you say that your answer has that property, it eliminates all the answers that don't have them. Repeat it a few times and you're left with a final answer.",
"So, Akinator has a database of questions it can ask, which is connects with its list of possible figures. Over time, it learns to associate certain questions with certain figures. On the desktop version, you can (Or at least used to be able to, I’m not sure now) see what answers it expected you to give once it has guessed your character. It also used to ask for your age to help narrow down potential suspects. Though I’m not sure if the mobile any newer versions still have some of those features.",
"It’s just process of elimination. You’ll notice that it quite often asked the same/simular question multiple times in different ways i.e ‘Is your character a female?’, ‘Is your character feminine?’, ‘Is your character a woman?’. It’s just incrementally eliminating possibilities from all of it’s lists of traits based on the context of previous answers until there are only a hand full left, and it will pick one. You’ll also notice that if it’s wrong and you continue, it almost always gets the next one right, because that small pool is then further eliminated from. And that list of traits to characters grows every time someone beats him and inputs their character. Obviously you can still beat him, but you have to get pretty obscure these days.",
"It's....game of 20 questions. A very well understood game of divisive choice making. It would be pretty easy to compile a list of popular fictional characters and attach attributed to those characters that can be categorized and queried on. You're talking a dataset that's probably only in the millions. Thing is...your dataset doesn't need to be complete at day 1. It just needs to be reasonably substantial to make the guesses have a good shot at being correct. There's no real penalty for being wrong."
],
"score": [
20,
8,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqmffy
|
Why are the capacitors so big, while the transistors are tiny?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frtl9gb",
"frtkf2i"
],
"text": [
"They are very different kinds of devices. All a transistor (in a computer) is doing is controlling the flow of a tiny current. This doesn't need the transistor to be large, in fact it can be very small and still do its job brilliantly. However if we look at transistors that are designed to deal with bigger currents (inside a power supply for example), they are larger as they need more material to not be destroyed by the larger currents. Capacitors are essentially two conductive sheets very close together. The capacitance is directly related to the electric field within the capacitor. To increase the strength of the electric field we can move the sheets closer, make the sheets bigger, or put a better dielectric (a material) between the two. If we have reached the limit of how close they can get, and already have the best material between them, then all we can do is make the sheets bigger. This means that we have to make the capacitor itself larger.",
"Transistors have some capacitance and making them smaller makes the capacitance smaller, which makes them faster. When you want capacitance, the the bigger you make it, the more capacitance you get. Integrated circuits (computer chips) that do analog things use small capacitors frequently. They tend to use more chip area than transistors. The worst offender are ~~instructors~~ inductors, so you really try to make an integrated circuit design not need any of those."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqny54
|
What's the purpose of complicated network servers?
|
I sometimes see these gigantic servers made for internet connection used for home networks. Why do average consumers use giant 24 port switches and other various things I barely even know about? What is the benefit of using those, when you can go to best buy and get a simple router?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fru06va",
"frtwk78"
],
"text": [
"Most home users do not need a 24 port switch. However there are cases where it can be needed at home. 1) you have a home theater and have shitload of devices you want to plug into internet. Sling box, Roku, chrome box, Xbox, ps5, Wii, some other internet tv boxes, 2) you have a big security camera system. It's not uncommon for high end mansions to have a many many security cameras that come together at the recording point. 3) you have many TV's and devices distributed in your massive house.",
"Sometimes you can get used equipment from businesses and try that out at home. Our you want to practice with enterprise level functionality where you won't get fired"
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gqofcc
|
Why does swapping order of two "dead" batteries provide more output?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fru0luc",
"fru224o"
],
"text": [
"It's not the swap, but the removal. It rubs a little oxidation off the terminals, reducing the contact resistance.",
"Electrical resistance in a layer of oxidation on the battery contacts will reduce the output of a weak discharged battery, in a way that really makes the weakness obvious. Scraping away some of the oxidation layer happens naturally when swapping around batteries. In fact, old-school electrical relays were designed to allow a very slight deflection of the electrical contact. That allows a subtle scraping action at the start of every electrical connection, so the contacts are self-cleaning. Separately, chemical diffusion will always seem to make a battery recover slightly when it's not ouputting current. The old-school Eveready batteries used a \"Nine Lives\" logo to highlight this effect in their batteries."
],
"score": [
55,
10
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqpxl5
|
How exactly does a compiler convert readable code into binary
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frudhl5",
"fruko1c"
],
"text": [
"The compiler translates the code into a much simpler coding language called an assembly language. We don't generally write code directly in assembly because each instruction in assembly tells the processor to do one specific thing. The assembly then gets encoded in binary - usually, one part of the resulting binary number says which instruction it is, and the rest is the data to use. So, you go from something like > a = b + c + d To something like > ADD a, b, c > ADD a, a, d Then to a binary encoding of those two ADD instructions that a computer can \"understand.\"",
"A compiler takes text and converts it into executable code. The compilation process is oftentimes split into _phases_. These vary from compiler to compiler, but at a high level they usually include _lexing_, _parsing_, _semantic analysis_, (optionally) _optimization_ and finally _code generation_. Each phase takes the output of the previous phase (or the source code), processes it in some way, and passes it to the next phase. Lexing is the process of splitting a stream of characters into _tokens_. This is usually the simplest phase. For example, lexing a program like `print(\"Hello \" + \"World!\")` could result in the following list of tokens: print ( \"Hello \"b + \"World!\" ) Notice how the spaces around the `+` are not included, because in this made-up language spaces don't matter, and can be excluded by the lexer. The next step is parsing, which is done by the _parser_. A parser reads tokens produced by the lexer and infers what a stream of tokens actually means: is this stream of tokens a function call, a variable declaration, a type definition or a syntax error? There are many ways to implement a parser and it's a pretty complex subject by itself. The parser usually produces an _abstract syntax tree_ (AST for short), a sort of abstract representation of the structure of the source code. Our made up program could have the following AST: FunctionCall ( \"print\", Add ( \"Hello \", \"World!\" ) ) The next phase is _semantic analysis_, which consists of multiple different sub-phases which take the AST and enhance it with more information. One such sub-phase is _name resolution_, which basically figures out what each variable or function really corresponds to. For instance it could figure out that the `print` function in our example corresponds to the print function in the standard library, or it could be a function we've defined ourselves beforehand. A related sub-phase is _type checking_, which goes through our code and makes sure our data types make sense. For example it could make sure that we don't do something nonsensical like subtract a list of numbers from a string of text, unless we're compiling JavaScript of course. In our example the AST could look something like this after semantic analysis: FunctionCall ( StandardLibrary::PrintString, FunctionCall ( StandardLibrary::ConcatStrings, String(\"Hello \",), String(\"World!\") ) ) In this example, the semantic analysis phase has figured out that the `+` in our code actually meant string concatenation (because both of its arguments were strings), so it automatically converts it into a string concatenation function call. The next phases are optimization and code generation, and they are usually intertwined: some optimizations are universal, some depend on what platform we're targetting. In this phase the AST could be converted into a different intermediate form, or it could be directly converted into machine code. For the sake of brevity let's imagine our code is converted into an _intermediate language_, which someone else finally converts into machine code. This is a common approach in modern compilers, for example ones based on JVM (Java, Scala, Kotlin), .NET (C#, F#, Visual URL_0 ) or LLVM^* (some C & C++ compilers, Rust, Swift). ^* JVM and .NET usually ship the intermediate language code (known as bytecode) to the end user, and the last step of compilation happens on the target computer. LLVM is usually used to compile everything to machine code in one go. The code generator (sometimes known as _emitter_) goes through the AST and converts a structured syntax tree back into a linear list of instructions, essentially doing what the parser did but in reverse. With our example program, the intermediatep language output could look something like this: PUSH \"World!\" PUSH \"Hello \" CALL StandardLibrary::ConcatStrings CALL StandardLibrary::PrintString This is getting close to machine code! This is a linear sequence of instructions, which can be executed from the top to bottom. I'm not going to explain the code in too much detail, but I'll mention that our madeup intermediate language uses a _stack_ to pass function arguments and results, so they need to be passed in reverse order. Optionally, the optimizer could go through our sequence of instructions and figure out that both arguments to `StandardLibrary::ConcatStrings` are constants, and do the concatenation at compile time, resulting in the final code of: PUSH \"Hello World!\" CALL StandardLibrary::PrintString"
],
"score": [
3,
3
],
"text_urls": [
[],
[
"Basic.NET"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqs0ia
|
Apple makes iPhones that they themselves cannot break into. How is that possible?
|
I would love an analogy or simple explanation of how someone can design a system that is locked/unlocked using a number string, but also have no possible way to reverse engineer or figure out that number string, having intimate understanding of how that system works. Is there a way to illustrate this using like, simple math or boxes with padlocks or coloured balls in a bag etc.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frul1te",
"frujc5y"
],
"text": [
"Take the formula Z x Y = 100. If we don't know what either Z or Y is then you there' s no way to solve that problem. You can come up with a list of possible solutions - Z = 2 if Y = 50 is a possible solution, for example. But we have no way to know if that's actually the case. And its only practical to come up with that list of solutions because 100 is a small number. If we change the 100 to 100 trillion then the list of possible solutions is so big as to be meaningless. So imagine that Z is the data on the phone. The phone encrypts that data by running it through the formula where Y is a really big randomly chosen number. This produces an even bigger number as the solution. If you don't know what Y is, then the best you can do is produce a list of solutions that is so gigantic that its totally meaningless. If your follow up question is \"but isn't all but one of those solutions garbage data?\" The answer to that is yes. Only one solution to that problem will produce coherent data. So if you just started plugging numbers into Y, the phone would eventually turn on and function normally and then you would know you had solved for Y (and by extension, also solved for Z). The problem with that is that the only way to solve for Y like that is to solve the formula for every possible number that Y could be. To counteract this Apple has made it so that there are so many possibilities as to what Y is that running through all of them would take millions of years - even with the most powerful computers on the planet. Even if you get *really* lucky and just happen upon the correct value of Y after having gone through 10% of the calculations, you're still looking at tens of thousands to hundreds of thousands of years to be able to unlock that phone.",
"Encryption is beautiful. Take a word. Change every letter into its numbered position in the alphabet. Multiply each number by the number in the next position of that particular word. Put those numbers in ascending order. Remove anything below 50 and above 300. Keep just the first 50 digits and fill with zeros if needed. Ok? Now I give you the another result only. What was the new original word? That’s the password to decrypt the rest of the data. Apple knows the recipe, but not the ingredients. Summary: the only way to make sure the original word is the same is by doing the same recipe and getting the exact same result. Any small change will result in a vastly different outcome. Going backwards (generate random or probable values to match the initial word) would take forever. There are mathematical ways to ensure that it is safely above current and foreseeable computing power."
],
"score": [
6,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gqsut4
|
How does downloading stuff work?
|
How can my computer take files off of a website, download them, and even continue to download them even if I closed the tab where the files came from.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frunzns"
],
"text": [
"Basically once you click on download your Computer makes a (completely separate) request to the Server for that file, the Server then (usually) simply starts sending you the File piece by piece until you've got everything, closing the tab doesn't stop the download because it's separate from the tab."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gqtiq9
|
How do logic gates work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frut53w"
],
"text": [
"Logic gates take one one more logical inputs. These don't need to be electrical: it's perfectly possible, for example, to build logic gates that work on marbles, or dominos, or push rods, or water flowing. All that matters is that something can exist in at least two states (water flowing versus not flowing, electrical charge present or absent, marble present or absent, etc.); these correspond to logical state, often called high and low, 1 and 0, or on and off. Most logical gates are electrical or electronic. Many revolve around the transistor, which for these purposes if just a switch for electricity that can be switched by electricity. Let's consider one of the simplest gates: an inverter. Input a zero, it outputs a 1. Input a 1, it outputs a zero. So all you have to do is have your transistor set up so that it's input power (which is electrical high, at 1) attached to the output. When the transistor's control is 0, the output is at supply voltage, or 1. But send the transistor a 1 to turn it on, and it will conduct, forcing its input line to 0, or ground. There are a few other components involved, but this is the basic idea. Or take an AND gate; it will output a 1 only if all of its (two or more) inputs are 1. So just take a transistor and supply it with some power to switch. Its control input is one of the gate inputs; its output supplies power to a second transistor. The second transistor's control input is the other gate input, and its output is the gate output. If the first transistor isn't turned on, there's no power to send to the second or out of the gate. If the second isn't turned on, it won't send any power to the output. Both have to be turned on for the output to be 1."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqui02
|
Why are power packs in Physics lessons so big, if e.g. the charger for a phone is so small?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fruxpko",
"fruxt2b",
"fruwq5a",
"frvas13"
],
"text": [
"The charger for your phone is not a battery pack, it's a transformer (voltage reduction), diode bridge (to convert AC to DC) and a bunch of control electronics. If you refer to power supplies, that has a lot to do with power output, expected use time (your phone stops drawing power when it's full) as well as heat dissipation under sustained load.",
"If you mean the ones plugged in the wall then because they have much more electronics inside to regulate voltage and current whereas phone charger only give out one regulated voltage and the cuircitry is much more simple. And phonecharger at most and those are the usbc type give out 60 w at 12 v and those powerbricks give out (some) 300w at 30v so they need much more cooling thats the reason behind the size difference",
"Smaller, equally powerful batteries cost more. You will see them get smaller as the cost of small, powerful batteries declines.",
"By power pack, do you mean a power supply? The charger for your phone can be so small because it doesn't need much in the way of components. Charging a phone doesn't take a lot of electricity, and that electricity has to be supplied to it at a certain voltage and current. The charger has a very defined input and output, so it can be optimized to do that while being small enough to carry around. Power supplies on the other hand, usually have a much less defined output. They're built so that you can dial in a specific voltage or current as needed. For example, a power supply may be able to provide anywhere from 0 to 50 volts, and up to 15 amps of current. This requires a lot of extra components to be able to provide a range of outputs. In addition, power supplies are dealing with much more power flowing through them, and for longer periods of time. This makes heat build up an issue. So now a power supply needs larger heat sinks, and probably a fan or 2 to keep it from overheating. Tldr: your phone charger is built for a very specific task, charing your phone. A power supply is built to do a lot of tasks, which means there needs to be more parts inside of one."
],
"score": [
7,
5,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqujnv
|
Why do green screens used for special effects have to be green? Why can't they be blue or any other color?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fruxa0b"
],
"text": [
"They tend not to use colours such as red or orange as people have red based features such as red skin tones or hair"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqy3i8
|
Transistors and how are they important in computers and other devices
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frvmjr0",
"frvmldb"
],
"text": [
"Perhaps man's greatest true invention to date. A transistor is a Semiconductor device ( a material that can behave like an electrical insulator or a conductor depending on how it is made, and the conditions it is in.) A transistor is typically used in two modes - Linear ( like a smooth ramp) or As an on/ff Switch (technical term is saturation) . In computers there are millions to billions of transistors in a single processor. They are being used as a basic switch, and are, on or off, in computer states this is High/Low or most commonly as bits, a single piece of information that is also referred to as 0 or 1 (binary as each bit can be only in on of 2 states, on / off) . So from VERY basic, single switch - they assemble very complex systems used in computers. In Physics, Electrical Engineering and Computer Sciences - we study them at different levels. Physics and EEs - may look at the basic Semiconductor materials EEs look at the transistor circuits, and then assemble them into DIGIAL Circuits - and into Computer Architecture. Comp Sci can work on the Architecture and the Software to operate (run) the computer.",
"A transistor is fundamentally just a switch. While there are a variety of underlying technologies, the most common is the MOSFET. You have 3 pins: gate, drain and source. If you apply a voltage (or take away - they can be built either way), a current path between drain and source will be opened and electricity can flow. Otherwise, the current path remains closed and electricity will not flow. With a small number of transistors, you can create a variety of logic gates - operations like AND, OR and NOT. By combining logic gates with clocks, you can create memory. By combining logic gates, you can create arithmetic operations. You can also create mechanisms for routing signals to control where information flows. As you scale up complexity, all of these various components can be combined to create the computer performance you see."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqy5by
|
How does VirusTotal check files for viruses only with checksums?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frvii98"
],
"text": [
"Essentially VirusTotal is a massive database that saves info from the first time the file was seen. If you upload a file or search for a checksum, VT looks to see when the file was last scanned and updates the results page accordingly. Files scanned 2-3 years ago, especially if clean, will have less info since fewer features (e.g. sandboxes, execution graphs, engines) were available. Plus, there really isn't much to be gained from cleaned files as technology evolves. It's better to keep more info on malicious files so you can use them as references. Some AV companies use VT as a lab, since new files are scanned by server versions of their products. If the file is malicious, VT gives them more info and will store the file for years. Clean files might only have the hashes and file properties, which are less useful."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqz02t
|
How does FBI or Law Enforcement Agencies extract data from any Android device whose bootloader can't be unlocked and thus can't be rooted ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frvrhtk",
"frvv2qv",
"frvrn13"
],
"text": [
"They mount the storage medium to a different device. If they don't have a USB-based method of doing so, they can simply take the Android device apart, unsolder the storage medium, solder it into a compatible device, and read it that way. If a 256 bit encryption using a secure algorithm and strong password has been used, the FBI is shit out of luck unless you forget to ask for a lawyer, but any less well regulated agency or criminal organization [will simply get you to tell them]( URL_0 ) your password.",
"you don't use the onboard computing device to read the storage. you remove the storage completely and use your own device to read the storage",
"The most brute force method would be removing the memory chip from the device and installing it in a special computer controlled by the agency. There are also tools like JTAG debugger which allow controlling CPUs and memories in-place by turning them in kind of zombies and making the CPU execute whatever instructions you want. I'm not an expert in forensic data analysis so there are probably many more elegant ways to do it. Of course encrypting phone's memory makes this task much more difficult."
],
"score": [
23,
5,
3
],
"text_urls": [
[
"https://xkcd.com/538/"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqz9dm
|
What is the iot (internet of things) and why is it important?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frvp1ih",
"frvox2d",
"frvyvs4"
],
"text": [
"IoT generally refers to appliances and common electronic items that use the Internet for enhanced functionality. For example, Samsung sells a gas stove and a kitchen fan that both have WiFi; the stove can tell the fan to turn on based on the amount of heat being generated. It is important because this enhanced functionality is pretty cool. For example, you might have a thermostat in your home connected to the Internet that lets you check from your phone whether or not you turned down the heat when you left home. Or your thermostat might have a little intelligence built into it and be able to check the weather; if it is cold it can turn on the heat automatically and if it is warm it can turn on the air conditioning. One of the biggest problems with IoT so far is that many of these devices have been built with little or no security built in, making them candidates for viruses. There are (I believe) IoT powered botnets that can do denial of service attacks.",
"Well, now a days, it's basically just a marketing term. It started out as a computer science concept, to describe things normally not internet capable bring out on the internet. wiki TVs, refrigerators, thermostats, cars, etc. It's things not normally used with the internet. Now, pretty much everything is on the internet, and it's just a corporation buzz word used to sell you kitchen appliances you can control from your phone.",
"A lot of people are mentioning consumer gadgets as the basis of IoT but it's more about industry infrastructure. While your consumer devices still fit in the category of IoT, the more impactful facet of this industry is the connectivity, control, and associated data resulting from everything from a ventilation fan on the roof of a building to the metering of an oil well. There are billions of devices out there that have historically been interconnected using legacy protocols and very few of these systems were connected to the internet. Now, businesses can access dashboards with which to control, monitor, and measure trends with relatively low capital required. The enormous amount of data and control can lessen operational costs and allow for predictive data to save energy, labor, and replacements in the long run. A good example is elevators. They have had software out there long enough capturing data to be able to predict when failures will occur and can do replacements or maintenance proactively, which saves big money."
],
"score": [
10,
3,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gqzbtg
|
How exactly do websites generate valid gift card codes for other retailers?
|
Specifically, what's happening on the backend for these codes to be generated and validated?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frvuq56"
],
"text": [
"the website doesn't generate them. the website backend calls the other retailer or the gift card network to generate a card number and pass it back to the website to pass to you"
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gr1ocs
|
Why does having console standard hardware in a PC cost so much in comparison to game consoles?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frw3xln",
"frw4od9",
"frw5nqy",
"frwhc97",
"frw44e0",
"frwtmcx"
],
"text": [
"Console's are mass produced and sold as a unit whereas computers are generally not, and even then far less are created using the same exact parts. If you pay for a bulk order of 50,000 units compared to buying the parts yourself and building it, the bulk order is going to get a cheaper deal",
"Game consoles are typically sold at a loss. PC's are not only not sold at loss but also have profit margin.",
"The stock answer is \"because the companies that make the consoles sell them for less than it costs to produce them because they want to sell games.\" That used to be true, but hasn't been true in a long time. The current reality is that when a gaming site tries to figure out what the \"equivalent\" hardware in a console is that isn't super meaningful, because console's aren't general purpose PCs. They have a custom made motherboard in which nearly everything is being handled by the GPU. While the GPU itself is based on commercially available graphics cards, its had a lot of stuff cut out of it. For example, it's unthinkable for even a low end computer graphics card to not have multi monitor support - which is a costly feature to include on a card - while no console, present or future, supports that. So when you buy a console you're not buying something that is directly comparable to any general purpose PC. What you're really buying is a Frankenstein's monster of a graphics card that's had a lot of its core features cut out, while having core features from other PC hardware added into it so that it can play video games and run a very basic UI.",
"The most basic answer is that they don't. You should easily be able to find parts lists out there that perform similarly to consoles for the same cost or lower. This could easily be seen when the updated xbox and ps4 came out and every PC youtuber put out a bunch of videos showing how to match the capability of those consoles with a PC for the same or lower cost. Consoles are able to get their prices down in several ways: Mass production. There are many many consoles produced that are all exactly the same or extremely similar to the point of being indistinguishable to the user and manufacturer unless they look at individual part numbers for the various parts. Selling services and games as opposed to consoles. You still have to buy the console and nowadays you pay full price for it as opposed to years past when you paid less than the cost of the console. The company (Sony, Nintendo, etc.) makes more money from the subscriptions and games than from the console sales. Functionality. Largely consoles serve as a way to play video games. Although they have added more functionality with each new release, a computer has much more functionality than a console outside of certain limited circumstances. More functionality equals more cost, and consoles are not computers with all the functionality that computers provide.",
"Because you dont buy in bulk. When manufacturers buy the chips for the console's, they are not buying them one at a time, they buy a lot at one time and they have a contract with the chip producer. So they get a discount because of buying more.",
"Consoles are sold at a very low profit margin (comparatively) and they make up for that in games sales and monthly subscriptions and so on. You buy a console you buy into an ecosystem controlled by one company, they are willing to lower their margin to acquire a new long term customer."
],
"score": [
252,
99,
56,
12,
5,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gr3as8
|
How do people in private islands get internet? Do they have their own ISP?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frwfd6c"
],
"text": [
"They don't have their own Internet. They pay an ordinary ISP, probably for satellite Internet data service. Their provider takes their packets and puts them on the Internet."
],
"score": [
39
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gr50r4
|
Why can’t Twitter close its bot API to reduce the ongoing disinformation war?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frwp9wq"
],
"text": [
"It could - it just doesn't want to. Twitter's valuation is based on its active user count - the number of 'people' that user Twitter on a regular basis. If they started pulling the bots, that number would drop dramatically (no one really knows by how much, because it isn't in Twitter's best interests to know how many bots use the platform). That drop would cause a drop in valuation, which no one at Twitter wants to happen. Beyond that, sensationalism sells. Twitter doesn't mind the bots if they provoke a reaction from people - good or bad - because that reaction keeps people using the platform, and that is all Twitter really cares about."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gr79kg
|
How do zip files work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frx5wwi",
"frx5bov",
"frx5pik",
"frxd63b"
],
"text": [
"Consider the string \"AAAAAAAAABBBAAAAAAAAACCCCCCCCCCCC\" You can very easily represent that as \"9A3B9A12C\" You have \"compressed\" 34 characters worth of data in to 9 characters. Lossless compression generally revolves around finding patterns, and replacing those patterns with shorter bits of data that can later be turned back in to the full pattern. Instead of describing every red bit in a picture you group entire areas together. Instead of recording every word you point out when that word last appeared. Instead of giving all letters the same length code you give shorter codes to the most common letters, and so on. The more patters you can find and shorten, the better.",
"The replaced data is added to a dictionary file that gets appended to the end of the ZIP file. This dictionary keeps track of the binary strings that were replaced, and the ZIP program knows how to put that data back in its proper place.",
"How do zip files work. 1 2 3 4 5 Attach a number to each word. “Work” is now 5. Instead of storing the full word, I store a table of numbers to words, along with the number representation of the sentence. Suddenly I’m storing much less text. The more commonly a word is repeated, the more effective this method is because the number for each word takes up less space than the full word. Compression is the process of optimizing this lookup table of numbers — a “dictionary”, if you will — to the original word. Maybe I can find whole sentences repeated a few times. That whole sentence gets its own entry in the dictionary. Decompression is just reading the dictionary for each number you have in order. This is called lossless compression. I have the exact representation stored. MP3s and GIFs use a different method and lose some of the original. Maybe they store part of the original word in the table instead of all of it.",
"What you've described is known as Lossless compression where, as other have stated, your computer will find similar pieces of information and group them: AAABBBCCC becomes 3A3B3C When you unzip them, your computer can then take this compressed file and rebuild it back to the long form - no data lost. The other type of compression is Lossy compression: Similarly to Lossless compression, your computer will find similar files, but instead of grouping them, it will delete them (how much gets deleted depends on how much you compress) AAABBBCCC could become ABC By using lossy compression you can save even more space and can transfer files faster, but the catch is, the files that are deleted are permanently gone. They cannot be rebuilt, so your file can sometimes be noticeably worse in quality. What determines this is? The file type. JPEG files are lossy while PNG are lossless. MP3 are lossy while WAV are lossless (to name a few). It's important to know this beforehand. So you can either have a lot of saved space at the cost of permanent data loss (lossy) or you can save a little less space, but have no data lost (lossless)"
],
"score": [
11,
5,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gr9b19
|
How does one way glass work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frxh7hc"
],
"text": [
"One side of the glass is reflective, but has many tiny holes in it to let light through. The other side is in a room that is darker than the room with the reflective side. Though some light gets reflected and looks like a mirror enough light goes through the holes you can see what’s on the other side although a bit dimmer than through normal glass."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gr9lx1
|
I understand early humans harnessing fire from brushfires or lightning strikes, but how did one of these cavemen make the mental leap to the process of friction, and that enough of it would generate fire?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frxlm9p",
"frxjcf4",
"frxjdd6",
"fry15xw",
"frxr4rc"
],
"text": [
"Well my complete speculation is rubbing things together will make them progressively hotter via friction. Fire is very hot. Ergo, rubbing two things together for long and fast enough will lead to fire.",
"Well, they were flint knapping to make tools. I can see how the flint could've sparked a bit of brush. Eureka! LOL",
"I don’t think anyone can give the exact answer as no one was there but if you imagine how small the world would have been to ancient peoples. Exploring the world around you would have been sticks, rocks, plants, animals and that’s about it. The first humans playing with fire may not have it it friction-wise either. Could have been flint rock.",
"While all we can do is speculate, it is very likely imo that the first fire via friction was formed by someone who was doing woodworking and noticed it getting hot. I mean, rubbing a wood tool against a wood substrate may have been meant for drilling or something, and that would generate heat. From there, either someone noticed sparks or noticed that it was hot and tried to make it as hot as possible creating sparks.",
"I'd like to think it was along the lines of understanding that fire and heat are related, rubbing your hands together makes them warm (friction). There's been plenty of times humans have worked out things from loose understanding of a concept."
],
"score": [
6,
4,
4,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grbyql
|
How do modern 3D glasses work?
|
I'm pretty sure I get how the old school red/blue lenses work. Some stuff is red and some stuff is blue on the screen, and it makes each respective color invisible through its respective eye which tricks the brain. Sweet. But the modern ones are both just clear lenses and the image on the screen just has stuff that's blurry. How the HELL do those clear lenses make some blur go to your left eye and some go to your right?? I am thinking of Mickey's Philharmagic-style glasses/video here, so if there are even more modern glasses than that, well, surely we as a civilization can't be that far from a COVID-19 vaccine then...
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fry0263"
],
"text": [
"Light is a wave, and that wave can be an up-and-down wave, a side-to-side wave, or some angle in between. This is called polarization. The lense over one eye only lets in side-to-side waves, and the other one only lets in up-and-down waves. There are two projectors with similar filters. You can actually see this for yourself by tilting your head sideways when you watch a 3d movie."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
grccpl
|
how does a printer work? I’m still confused
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fry2rol"
],
"text": [
"There are two main kinds of printer in the world that I'll discuss here. **Inkjet** printers work as the name implies: the ink cartridges spray a jet of very fine droplets onto the paper, which make up the image. **Laser** printers do *not* work like the name implies. The laser is not directly responsible for printing the document; rather, the laser is used to remove an electric charge from a rotating drum. That drum then picks up *toner* (charged particles of dry ink) from the cartridge. The toner particles, being negatively charged, stick to the places on the drum that the laser hit. The drum continues to rotate, pressing the particles onto the paper and fusing them."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grdgj6
|
How do hackers find your password and hack into accounts?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fry8sf6",
"fry8ntt"
],
"text": [
"Two major ways: - From hacks from other sites. If say Adobe has a breach and you used password \"hunter2\" there, hackers can try that email/password combo on other sites. - Phishing: tricking you into giving up the password voluntarily. This can happen by designing an identical login page to (e.g.) Facebook, so you sign in with your Facebook password unknowingly. Phishing can also happen over the phone, like if someone pretends to be from your bank.",
"Mostly, you unwittingly hand it to them. Occasionally, someone with access to your password unwittingly hands them their password, and thus yours as well. And because you use that same password on your email, now they can reset all your other passwords."
],
"score": [
7,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grdqa9
|
What does RAM contain that allows it to do its job?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frya445"
],
"text": [
"RAM is actually a bunch of capacitors. Think of it as many tiny batteries that's continually discharging a bit. If they want to set it to 1, they put some electricity in it. If they want to set it to 0, they drain it. Every now and again, they have to top up the capacitors containing 1s with more electricity. All of this happens literally in the span of a few nanoseconds. Do note, CPU caches can accurately be called RAM as well, specifically Static RAM. Though it rarely comes up. The RAM described above is Dynamic RAM, it's the stuff most people are talking about when they say RAM. CPU caches work differently. They're even faster, but horrendously expensive compared to DRAM. They work by a bunch of transistors wired up in a certain way."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grds3m
|
How do you get sound out of a plastic disc?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fry9zl4"
],
"text": [
"simply put, teeny tiny pits are burnt into the CD in an inward spiralling groove. when your cd reader plays it back, a laser tracks the pits and interprets them as ones or zeros, and then software decodes it into files, audio, video etc."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grfus9
|
Why does adding a . (dot) after the URL remove website pay-walls?
|
URL_0 answers this question, but the answers there are too complicated! Please ELI5 them?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frymeik"
],
"text": [
"Those websites are tracking you via data stored on your own computer. They do this to enable certain 'trial' functionality (or, first two articles free). If that data gets removed, you get treated as if you were a new user. (This is why deleting local browser data can reset paywalls on some sites) The mechanism that allows for this in browsers stores all the different websites local data is keyed based off the domain. Basically, if Yahoo says \"store this data for me\", your browser records \" URL_0 : < data > \". Now, for reasons having to do with the design of domain resolution, your browser considers \" URL_0 \" and \" URL_0 .\" to be two different websites, even though during normal use they would resolve to the same place. Because they technically could resolve to different places, the browser treats them as different. Thus when URL_0 says \"store this data for me\", your browser will key it based on the version you visited. Note that this will only remove paywalls on sites that use local tracking to determine it. That is, sites that you can get this exact behavior by clearing your browser cache. If the paywalls is keyed off of a value server-side (such as requesting ip), this will do nothing."
],
"score": [
5
],
"text_urls": [
[
"yahoo.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
grfx7u
|
Why hasn't anybody managed to create a laptop or smartphone screen that you can use in the sun without huge amounts of glare yet? It seems impossible to use most devices in the sun without having to squint past your own reflection!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frym3e4"
],
"text": [
"Because the sun is extremely bright, like 100,000 lux on a sunny day compared to indoor lighting being below 1000 lux. Bridging that factor of 100 is not currently feasible for battery-powered devices. E-ink can solve the issue by being reflective, so it works fine outside. But it can’t do bright colours or moving images so it’s not suitable for most computer applications."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grgdvt
|
How can 4KB take us to the moon but barely run a phone?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frytesn",
"fryo9ve",
"fryooar",
"fryofqz",
"fryqyel",
"fryrwj0"
],
"text": [
"First: 4KB is just the RAM the Apollo guidance computer (AGC) had for its computations, in addition to that it had about 70KB of read-only memory, containing all the program code. Second: With the AGC, there was a team of geniuses working *really* hard on basically writing one program for that specific computer, doing just one specific thing. It also helps that the computer was designed specifically for that task. Modern Computer Science however is all about *abstractions*. For example, if you want to write a program that draws a circle on the screen, you don't want to spend time calculating circle-math, and you don't want to figure out how to talk to the specific screen and say \"please make pixel X Y blue for me\". You will probably want to use *libraries* and an *operating system* for that. But chances are that your circle-drawing-library isn't just for drawing circles, but it can do rectangles and triangles and lines too. And your operating system doesn't just support one type of screen. All of this now has to be included on your system. Every new *abstraction layer* adds new complexity (and also makes your program a bit slower), and in a phone there are probably *a lot* of them. That's not always bad - it's great that creating things is easier than ever! Third: Going to the moon isn't *that* hard, from a computer science perspective. Don't get me wrong, the AGC was an absolutely tremendous achievement at the time. But your phone could absolutely perform those tasks and still have 99.9% processing capacity to spare. It mostly boils down to calculating a few equations on your sensor data to track your current position, and compare that with where you want to be going (of course, there are some other things like remembering that someone pressed the \"abort\" button, which drastically changes the \"where you want to be going\"-part). The AGC wasn't even on its own there - it had highly trained humans on board to help monitor the situation. Compare any modern video game with a physics engine: there you have any number of objects flying about, and any two of them could interact. That's a much harder problem than just keeping track of one spacecraft, which is basically just freely drifting through space for the most time! Edit: made a mistake when converting the memory sizes Tl;dr: Having a team of world-class experts build a specific computer for a specific task will result in a much simpler design than trying to have a device that can do about anything and that's extremely easy to program for.",
"Assuming you're talking about memory here. It's plenty enough to run a phone, but just not enough to run all the other shit on it.",
"Basically it's about what you store on it. 4KB is 4000 Byte. 1 Byte = 1 Letter. So imagine how many equations you could write with 4000 letters. If you basically just have simple text, and a couple.lines of code to calculate, you don't need much space. Even these days, a text document with 4000 Letters on it is 4KB. What's big is images and sounds. Because for every pixel you need to store it's color value, transparency, and color depth. It just takes a lot more storage",
"no expert on this, but the computers taken to the moon were basically simple calculators, the astronauts had the training to use these to perform the equations that they needed for a successful flight. meanwhile the calculator built into a modern phone is likely already more powerful than that, plus it runs a colour screen, internet connections and is doing a hell of a lot more behind the scenes to get everything working. 4kb would be plenty for your phone if all you wanted it to be able to do is adding, subtracting, multiplication and division...",
"In one sense, they had less powerful computing devices but hundreds of PhDs and multiple degree holders and decades of training in their field. Also it was a very focused mission - so things are purpose built for very specific needs. The phone has to work for nearly everyone with no specialized training. The computing power is there to make up for the untrained user. And the ability to run many different applications.",
"Because of all the abstractions created over the years. So say you have a hard drive and you connect it to a computer. In order to use this drive you would need to know the \"language\" that it operates on - how to say to the hard drive what block of data to write, what it should contain, what block of data to read, etc. Given that, every program that wants to work with this hard drive would have to know it's language. But implementing this functionality on every program that wants to use the hard drive would be a nightmare - different drives could have varying languages, multiple programs could use the drive at once (causing conflicts), etc. That's why we developed a level of abstraction called an operating system. It basically acts as a translator between the high level requests of program (for example the program could say to an os: \"I want to write to a file students.txt the following data: Steve, John...\") to a low level language of hardware (operating with a hard drive on a block level, because hard drive itself has no idea what a \"file\" means, it's only an abstraction). Besides hard drives we also have graphics cards, sound cards, printers, keyboards, mouses, usb devices and so much more and every single one of them has it's own language. The operating system's job is to translate the high level requests of programs to a low level language of hardware. And there is a lot of this hardware, a lot if different requests programs could make and a lot of edge cases, the os also needs to prevent any conflicts between programs and implementing all of this requires a lot more processing power because it's not just single purpose - it's multipurpose, there is a lot of things we need to consider when implementing something like this. 4kb were enough to take us to the moon because the hardware was designed to perform one and only job, but your phone is a multipurpose tool - it can be used as a calculator, it can take photos, videos, it can send messages, make calls, compute complex 3d graphics and all of this requires their own levels of abstractions."
],
"score": [
20,
19,
13,
7,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
grhrae
|
Why do some PDF documents open immediately in a browser while others need you to save it first before it can be opened?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fryw3pn"
],
"text": [
"It depends on the server, specifically the [Content-Type]( URL_0 ) header. This header tells the browser what kind of content is expected in the file - an html page, an image, a video, an audio file, a pdf file, and others. If the Content-Type header is set to \"application/pdf\", then the browser knows this is a pdf file, and will present it. Otherwise, the browser won't know how to show this file, so it just offers you to download it."
],
"score": [
14
],
"text_urls": [
[
"https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gri9jt
|
When you record song by phone, why the record result is (sometimes so much) different from what we originally listen to?
|
Mostly the voices/songs become so much noises, while when we call someone with our phone, it sounds as crystal clear on the other side, so it is definitely not a mic issue.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fryy6kk",
"fryzkw5",
"frz49gk"
],
"text": [
"The original song was recorded with high quality microphones, then mixed by a trained sound engineer to become the song that gets distributed to listeners. When you record it with your phone, you are recording a recording (which will result in a loss of quality) using a lower quality microphone (which will result in another loss of quality), and the subsequent file is subjected to compression (which results in data loss, and another loss of quality) before the file is saved.",
"In addition to what Iamalext says when you call someone your phone is likely running an audio codec that's specifically engineered to efficiently work with voices. If you try to call someone and then try to make them listen to some music through the same mic you're using in the call it will sound distorted, because the codec wasn't designed to handle the more complex waveforms music usually has.",
"It IS a microphone issue. Not only, but it’s where it all starts. Microphones (like speakers and the audio formats) have specific frequency ranges where they operate better/operate at all. The microphone on your phone is specialised for human voice so it will pickup much better around the human voice frequencies (~ 1khz) and much MUCH worse the more you drift from there. Basically it won’t pick up anything on the lower frequencies of which music (depending) on the genre has A LOT. Try pointing your phone at a speaker playing music and ask the person on the other side if they’re still hearing crystal clear."
],
"score": [
12,
4,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
grjr41
|
why do some US outlets have 2 prongs and others have three?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frz6e8g"
],
"text": [
"The 3rd prong is for grounding the electronics. Typically the chassis or outer metal shell is connected with a direct wire to the ground, such that if any short were to happen between any wiring and the chassis, the current would flow through the ground and trip the breaker. It's a safety measure and was not common on old homes. Now I'm pretty sure it's a requirement on new homes in most states."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grjw1l
|
What technology do ISP's use to store browsing history for which the feds have access too any time they want?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frz99ue"
],
"text": [
"They can see what requests you make to view websites, they know your IP address so they can keep a record of which sites you visited For example if 179.75.85.2 connects to 65.171.13.6 they know who 179.75.85.2 is and that 65.171.13.6 is google (the number aree made up) However they cannot see what you do in a website or your passwords and banking information as all of that is safely encrypted (unless the browser clearly says “not secure” on top)"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grmfvw
|
Why does rearranging the “dead” batteries in a remote control make them “alive” again?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frzoiek"
],
"text": [
"The remote probably had corrosion on the batteries or battery contacts. Moving the batteries scraped some of it off. If the problem comes back, try this as a permanent fix. URL_0"
],
"score": [
5
],
"text_urls": [
[
"https://www.bobvila.com/articles/how-to-clean-battery-corrosion/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
grmg18
|
What is RAM?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frzsdhj"
],
"text": [
"Imagine you run a kitchen that makes sandwiches. All the ingredients are stored in cupboards and refrigerators. That's your hard disk space. You have a counter area in front of you where you look at the ticket orders and take the ingredients and actually construct the sandwiches. While your storage can be immense (pounds and pounds of meat and peanut butter and mayo), the counter is only big enough for one person to actually make the sandwiches. The counter area is continually filled and cleared as you get ingredients, make sandwiches and hand them off to customers. The counter area is RAM."
],
"score": [
27
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grn68z
|
what makes a TV movie look like a TV movie and not a big budget production?
|
I know it’s something to do with the cameras used, but what makes a big movie look different than a low budget TV movie or sitcom? Is it something to do with FPS, resolution etc?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs0bxia",
"fs0gt29",
"frzt2bi",
"fs1ueck",
"frzuq5n"
],
"text": [
"In addition to the other comments here there are a few others things: * More close ups: Domestic TV screens were usually quite small compared with the movie experience. As a result directors tended to use more close ups. Faces, and the expressions they have are necessary to convey the story line and if shot in the same way as for movies, they would simply not have been visible enough for a domestic environment - so you get more faces and they are closer. * One side effect of the above is that titles on made-for-TV movies tend to be bigger so they can be read. Typical movie credits are often too small. Similarly things with writing such a phone screens, monitors, books, signs, letters are all closer. * Fewer longshots: Similarly, large panoramas, distant landscapes etc look great on a big screen but on a smaller domestic screen a lot of the detail and \"atmosphere\" is lost so these tend to be less frequent and also closer. * Fewer \"blacks\": Movie theatres are generally darkened so you can have deep dark shadows on film and still see into them. Domestically, TVs are often watched in a more brightly lit room. Those dark scenes would be impenetrable so lighting tends to be turned up and less contrasty for a TV movie.",
"I'm surprised nobody mentioned a rather large part between the two. Movies are [color graded]( URL_0 ) to a higher degree, like in this [example]( URL_1 ) (notice the orange and blue hue differences, in real life they didn't look that blue/orange). Most people don't realize it, but there are usually people hired in a movie production whose job is to painstakingly color grade each scene for a cinematic effect. [This]( URL_2 ) is a direct comparison. Notice how in the movie everything has a green-ish/blue look to it? It's extremely memorable and is often done to give movies \"artistic themes\", like the Matrix did with its color grading while Neo was in the Matrix. It can completely change the mood of a scene with such a simple change, [like in this photo]( URL_3 ), the one on the right uses more cool colors for a more depressed, ragged look, whereas the 'true-to-life' looks more healthy and positive",
"Typically new shows are shot and broadcast at 4k/1080i 30fps, using cameras, lighting, and lenses that tend to keep everything evenly lit, and in focus. Cinematic shows can be shot on either film or digital. The framerate first of all being reduced to 24fps, because this is just the cinematic \"feel\". Plus they tend to use more deliberate lighting, lenses, and framing.",
"You have to understand that on a big budget production...they have a big budget. Every element that the camera \"sees\" is tailored to specifically what the director saw in their mind as they read the script. (Arguably, this \"vision\" is part of why directors are chosen. A John Ford movie looks like a John Ford movie, and that's something a studio is willing to pay for. They're willing to pay this guy a buttload of money to be a prick and say \"That horse on the far left, #412 of the scene, he led with his left forefoot. This is a right-hand regiment, reset, rebuild that wall brick-by-brick, prepare to reshoot, and get that horse taught to walk properly!\") A made for TV (MFTV) movie is much more of a \"it is what it is, actor walks here, delivers line\" product. They don't have the budgeting to really care about the tiniest little detail of a scene. If a jar in the background is reflecting a highlight, as long as it's not really distracting it might be left in this scene and the object moved before the next shot. In a big production you get a composer writing music played by a 100-piece orchestra. MFTV movie, you get \"Sports Highlights Sound Reel 4\" in MIDI format in the background. In a big production, you have someone who is 100% in charge of nothing but lighting, and that person may have hundreds of tint gels to make this light a specific hue for this scene. MFTV, well, this light is \"on\" and we can turn it \"off\", but mostly we want it \"on\" because we want to \"See\". Other than that, um, lighting is okay, yes. In Willy Wonka and The Chocolate Factory (1971) one specific scene took over ***forty takes***...and it wasn't a scene that really brought the end result quality up that much. Good scene, but not exactly a crucial \"OMG if we don't get this it's all been for naught\" scene. In a MFTV production? I'm not seeing anybody doing forty tries at an essential shot that *is* crucial to the plotline. At best, we either get the \"best of the worst\" takes, or the scene would be rewritten around whomever can't get it done. The budget simply can't allow the production to take that much care and concern with a single scene. Get it done, get it shot, move on. If you're paying me $200 per hour to shoot this scene, you end up with a much better result than you'd get for a payment of a \"Buy two, get one half-price\" coupon for Ramen Noodles. Basically the ***TL/DR*** is that the budget for a studio movie allows the product to have a higher attention to the tiniest details that, alone, mean nothing, but together make the whole thing work artistically. It's the difference between a chef-crafted hamburger with home-grown tomato, lettuce, handmade cheese, hand-ground beef carefully selected for its fat-to-lean ratio...and the $1 Hamburger-Shaped-Object you can buy at Burger king. Both are similar, but you can really identify the differences in how much one is better than the other and how the small details combine to make the overall result better. This, of course, is in addition to other points others have made about a movie theater having a better visual translation than a TV or phone. The theater screen is what this piece is tailored for. Nobody is tailoring content to be viewed on a dozen randomly chosen TV brands and aspect ratios, they just go with a happy compromise that'll work on most. It's a compromised project whereas a big movie production doesn't understand the concept of compromise and doesn't have to.",
"It's definitely a combination of things. The length of shots, filters, angles, and editing all contribute to a film's look. In many cases less time and money is committed to the cinematography for a TV movie."
],
"score": [
111,
57,
29,
7,
5
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/Color_grading",
"https://i.imgur.com/pWyGp3I.jpg",
"https://www.psdbox.com/wp-content/uploads/2016/05/1-example.jpg",
"https://i.imgur.com/yCuxKke.jpg"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
grnutu
|
How do motion sensor lights work? In a dark environment how can the motion sensor light detect movement?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frzxsou",
"frzyqth",
"frzxqxg"
],
"text": [
"Most motion sensors are what are called passive infrared motion sensors. Basically, they are always scanning their viewing area for infrared light, and if there is a large change in infrared light, they report that as \"motion\". Humans (all animals really) are constantly giving off infrared light (in the form of heat). We can't see this, but it is always there. Since the senors _can_ see this, even in a dark room, they are able to work regardless of ambient light levels.",
"There are two types of motion sensors: passive and active. Active sensors work by sending out ultrasound waves. These waves bounce off of everything in the room and return to the sensor. Based on that echo, the sensor can compare two points in time to see if there are any differences. If there are, that means the sensor has detected motion. Passive sensors work a little differently, obviously, and there are two types of passive sensors: infrared and photo. Passive Infrared (PIR) motion detectors detect infrared light (that is, the heat emitted from our bodies) and - like with the active sensors - can compare two snapshots in time to detect motion. Photo sensors work by shining a laser to a receiver. If anything steps in the way of that laser, the sensor is detecting motion.",
"In most cases, they have a small ultrasonic transmitter/receiver pair. If those sound waves bounce off a moving object, they'll return at a slightly different frequency (due to doppler shift)."
],
"score": [
6,
4,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grrqka
|
How can data from my router come to my computer without being altered by all the walls and stuff in my house ?
|
If my router and computer are apart from each other in my house and that my computer is connected using WiFi, how can my computer still use the data that has been sent by my router even if there are walls and maybe my brother running in between ? Aren't the data affected by all that stuff ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs0u2my"
],
"text": [
"Data is constantly altered on the way from your router to your PC, at least if by \"data\" you mean the signal's waveform. Imagine it like listening to a talk show on an old AM radio. You might get lots of noise and crackling sounds and the signal might get louder or quiter, but if the signal is kinda OK, you'll still understand the words that the radio host is saying. Computers are similar: they don't care how *exactly* the signal sounds, they just care if it encodes a \"0\" or a \"1\". If things don't go too wrong, those \"sound\" different enough that they can't be confused easily. Occasionally though, things *do* go wrong, and a \"1\" might be received as a \"0\" or the other way around. Does that mean that you will see a wrong letter in a webpage? No, because we have a little thing called \"error-correcting codes\". Basically, it's like mishearing a word in a sentence: you'll likely still be able to figure out what was really meant by context alone. Similarly, wifi will include some special extra data that allows the receiver to figure out when an error has occured, and correct it. The last resort are *checksums*: When there are too many errors for the error-correcting code to handle, your computer will still realize that a packet has arrived incorrectly, if a checksum doesn't match. Then, it will have to ask the other side to simply repeat the transmission. Most of these concepts don't just apply to wifi - they are everywhere in modern life. For example, CDs use error-correcting codes while barcodes and credit cards use checkdigits (a simple form of checksum). The ability to duplicate data without any errors is really the reason for digitalization in the first place."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
grt64h
|
How can lasers shutdown a drone whilst in flight?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs1307i",
"fs0w9ba"
],
"text": [
"Even a hundred civilian handheld lasers wouldn't be anywhere near powerful enough to damage a drone. Even a thousand wouldn't do it (also their beams would never line up anyway). What probably happened was the drone was being flown by camera (and not by eye), and the pilot couldn't see any accidentally crashed it. The lasers are used to blind the cameras so using the drone and/or facial recognition technology becomes ineffective",
"There are probably multiple ways to skin a cat, so to speak. A laser is a source of concentrated energy, similar to a beam of sunlight coming out of a magnifying glass. You can burn stuff with that magnifying glass if you hold it steady and let the heated object absorb the energy. Laser weapons work like this. To make sure they deliver enough energy to damage their target, they use special turrets which track their target with sophisticated control systems, making sure the turret is always pointed at the target regardless of where it may have moved during flight."
],
"score": [
11,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grtar2
|
What was done differently for SpaceX to create more fitted space suits than NASA ACES suit?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs0ypa9",
"fs1067k",
"fs0zflj"
],
"text": [
"They hired the guy who designs all of the costumes in Disney movies (including the Marvel Cinematic Universe) to design the suit. That guy specifically designed them to look sleek and cool. One of the big changes he made was to not include any external pockets. The orange NASA ACES suit is derived from the pressure suit that was designed by the Air Force for high altitude planes back in the 50's. That suit was covered in pockets because personal computers and LCD screens weren't exactly a thing in the 50's. This meant that the pilots had to take a bunch of paperwork up with them - all of the charts, checklists, and everything else that the needed had to be printed out on paper and carried into the plane. The most convenient place to store this stuff was on the suit itself, which was covered in pockets to facilitate that. This basic \"covered in pockets\" design was continued on into the Space Shuttle era when it was still necessary for crew members to carry a significant amount of documentation with them which they needed to be able to access quickly. The state of current technology means that all of that paperwork can now reliably be accessed through LCD multi function displays or tablets, meaning that there isn't a reason for the crews to carry it with them, meaning that they don't need a suit that is literally covered in pockets.",
"They are not designed to do the exact same thing. One major difference the NASA ACES suit is designed for escape by parachute for a landing in the water where the SpaceX suites are not as the capsule can escape the rocket and land with the crew inside. The SpaceX suit also has a lot less mobility for the head as the hamlet is small and attached to the suites where NASA is large and removable. You can't tilt your head back and look up in the space -S suite. This makes the head and torso part of the suite smaller Then I suppose that the Space-X suites are designed to have a close fix as a style choice. They did not what a spacesuit that looks like a military flight suit adapted for higher altitude aircraft and space, this is the origin of NASA spacesuits.",
"the sts 130 suits, (nasa suits) were developed from high altitude aircraft suits, which were developed from early high altitude suits, which came from a combination of diving suits, and \"g-suits\" used in early fighter aircraft. that is, each individual part of the suit was inherited from the previous generation, and \\*together\\* work as a space suit, but overall, there was no single design ethic. that is : each part was designed to work with the existing suit, and was modified as needed for a particular mission, but no one ever, at any point sat down and \"designed a space suit\". & #x200B; Space X on the other hand, started with a blank sheet of paper, wrote out what the suit actually needed to \\*be\\* and what it needed to \\*do\\* and designed it as an integrated unit. & #x200B; the STS-130 suit was, for example, 4 layers thick. the inner layer was for comfort, then there was a thermal/cooling layer, then there was a layer that was designed to be air tight, THEN the outer layer was designed to stop things expanding. each layer was designed to go over the previous layer, but overall, parts of the suit were still fundamentally the same as the water heated suit designed to stop a b14 pilot from freezing to death. & #x200B; the spaceX suit on the other hand seems to have integrated at least the outer two layers, being made of a composite material that's both structurally significant, AND air tight, with integrated valves and pasthoughs.. and rather than having a valve for air, a valve for heating, a valve for cooling, a valve for potable water etc.. they have a single port on the thigh that allows multiple connections. & #x200B; one of the MAJOR differences between the two however seems to be the choice of joint design. the sts-130 suits use a metal ring at each major junction that allows the joint to rotate, and maintain structure. the spaceX suit seems to use a restricted bellows joint. (that is, there';s extra material where it needs to expand to allow the joint to flex, and strong non-expanding material where it doesnt."
],
"score": [
8,
5,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grtf5r
|
how does whatsapp makes money ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs0xkni",
"fs1c7lp",
"fs0yhne"
],
"text": [
"Whatsapp is owned by Facebook. Facebook uses it to collect data on its users. Facebook then sells data and targeted ads about you to other companies. You, the user, are the product which Facebook and all of its branches sell.",
"FB didn’t but whatsapp to make money. They bought WhatsApp to reduce competition and chances of getting beat. FB is making money by not losing money",
"But what data ? Everything’s end to end encrypted ."
],
"score": [
30,
5,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grthdq
|
Why do old cameras make a person’s eye appear red?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs0zr4h"
],
"text": [
"It's not so much about the camera as it was the flash. In a dark room your pupils are very open, so a flash would shine light inside the eye, which would reflect back red. In those days you would hold the flash further away from the camera so the lens wouldn't line up with the eye reflection. Over time they invented ways for the cameras(with their flashes) to do a better job, One way is to have a mini-flash before the real flash, which makes your pupils shrink for a second so they wont reflect so much. There are also built in programs for digital cameras that can figure out red-eye and paint it out before you even see the picture."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grubd2
|
How are microchips created?
|
Just watched this video on r/videos and it gives an explanation on how solid state memory works. However I'm completely baffled how something so complex could be manufactured at that size. Can somone eli5 how a chip like this is made? URL_0
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs15m9j"
],
"text": [
"Basically, it's a microscope, but the other way around. The actual pattern of the extremely tiny transistors and wires are printed on a *mask* that is quite a bit larger than the actual chip. Then, they shine light through it, and bundle it together to etch the details into the chip. That process is called [Photolithography]( URL_0 ). There is a bit more to it: light can't just etch transistors, there is a chemical called *photoresist* that is applied. This chemical reacts to light and is either hardened or softened by it, depending on the exact chemical used. Then, acid or plasma is used to remove the \"soft\" parts of the photoresist along with the silicon under it. This process has to be repeated, because a microchip has several layers that all need to be built separately. Fun fact: the transistors in CPUs have gotten so small that they are starting to have problems because *the lightwaves are too big*. Basically, if the features you are trying to etch are smaller than the wavelength of the light, then you start getting problems. They circumvent this by using UV light and making the shapes on the mask \"wobbly\" in a special way that compensates for this effect."
],
"score": [
8
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Photolithography"
]
]
}
|
[
"url"
] |
[
"url"
] |
grvjfg
|
How does a video game emulator work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs1brw0",
"fs1xtz6"
],
"text": [
"So, a video game is a complicated set of instructions for a computer about what to do. It tells the computer what to show on the screen, what to do if the player presses a button. Each type of computer, such as a video game console, has a special language that is needed to tell it how to work. It can only understand instructions that are written in that particular language, instructions that work with the special equipment it is designed for. So if you try to use a video game program on a different computer than the one it was designed for, it won't work. It'd be like trying to give instructions written in German to a Japanese man, the instructions may make total sense to a German person, but this Japanese man wouldn't know where to begin. Ideally, you would reprogram the entire game into the new language for the computer you want to play it in, like if you translated a novel into a new language. But that's very hard and complicated. So a video game emulator is like having a dictionary in a foreign language, it takes the instructions that were written in one language, and translates them one at a time into the language of the computer you are using. It can be much slower than playing the game in a version designed for your computer, but it makes it possible.",
"Starting with some context: Computers have a specific Operating Systems like Windows or Linux. Many games don't work on the wrong operating system (as many gamers will tell you after trying to game on a Mac/Linux). Game consoles also have their own OS which means their games don't run on Windows. An emulator basically sets up a single window running the console's OS (or as close as programmers can get it) so that it can translate various commands into \"console language.\" That being said, console companies don't just go around releasing their console source code. And if you've every played a game that got a bad port from one system to another, you can imagine something similar happening with the OS. Someone \"ported\" it to PC, and it might not work very well depending on how complicated the process was."
],
"score": [
25,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
grx1ns
|
Why do Space Launches have to go at an exact moment?
|
Today, Space X had a launch time of 4:33EST. The Nasa weather dude said "If we can wait 10 minutes, we can go." The mission was scrubbed. What's the reason they don't wait a reasonable amount of time?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs1l9b3",
"fs1sh0k",
"fs1w8li",
"fs227td",
"fs1n6hn"
],
"text": [
"I could be wrong but if I’m not mistaken it’s because the space station is in constant movement and they have to launch at that specific time to line up with the space station.",
"ISS missions have what's called an *instantaneous launch window*. That means the launch has to occur at an exact point in time. It can't even be a couple seconds too early or too late. The ISS goes all the way around the world in 90 minutes. So in 10 minutes the ISS will be a couple thousand miles out of position. Other space missions can have longer launch windows. If your target's not a small object near Earth, or if you have certain kinds of multi-step mission plans, you have options to make up for any delay in the launch.",
"Because if they don't wait, they won't have enough fuel to reach the ISS. The ISS is not orbiting the Earth around the equator. It goes very far north, then comes back down south in a slanted orbit. (It has a 51.64 degree inclination) It's not straight north-and-south, but it's closer to that than it is straight equator east-and-west. This was done so a lot more of the Earth eventually is under the ISS at some point. As the station orbits, the Earth turns, moving a new part of the Earth into the path of the station. This means the station can do science that looks at the Earth to many different parts of the Earth. The down side is that it's a lot harder to get stuff to the station. Space X has to launch when Florida is underneath the station's path, or close enough to it. This is the \"Instantaneous launch window\" Because changing how much you go north-south / east-west takes a lot of fuel. And getting to the ISS from any other time is going to involve several changes of course, a lot more fuel, and a lot more time spent in space. And just getting there is plenty hard as is. You can't take as much advantage of the spin of the Earth to get into orbit since you aren't launching the way the Earth is spinning. So now they have to wait a while for the Earth's spin to put it back underneath where the station is going. Also, I'm less sure about this. But the fact that the rocket's oxidizer is really cold liquid oxygen, might also mean leaving in Florida's hot sun might have warmed it up too much to be safe.",
"If the ISS passes roughly over the Kennedy Space Center heading south you have to launch around then to meet it. If you wait the 92 minutes for it to come around again, the world will have turned and it will be passing over central Mexico and west Texas instead. Basically the circle of a satellite's orbit stays almost still while the earth turns under it. Where the ISS is on its orbital circle doesn't matter so much; you can easily stay in a slightly lower orbit for a while and you'll catch it up. The more important thing is to wait for the orbital circle to be lined up with the launch pad. The way the earth bulges slightly at the equator does rotate ISS's orbit very slowly, so the time of launch is about 23 minutes earlier every day. Launch opportunities to ISS therefore come every 24 hours minus 23 minutes apart. The cycle repeats every 63 days.",
"For any space mission the control has to calculate exactly how much fuel they will need to reach the destination and return safely. Every ounce matters so they have to have as little weight as possible on the vessel. In order to minimize this, missions must be launched at a specific timeframe where the target and trajectory will be as close as possible. For a target like the moon, this is a relatively large window, and when the only goal was orbit, it was even larger. For a small target like the ISS the window may only be an hour before the entire operation needs to be scrubbed until everything is in a good position again."
],
"score": [
33,
19,
11,
7,
3
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[],
[],
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|
[
"url"
] |
[
"url"
] |
grxktt
|
How a game such as RDR2 or Skyrim can make the map feel so expansive and realistically large, yet you can travel from one end to the other in less than 10 minutes?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs1pjcm",
"fs4ag5g"
],
"text": [
"It has to do with what they pack into the space they have available. They scale distances way down so settlements are way closer together than what they would be in real life, and they utilize the space they have between them well. In the case of Skyrim, since a lot of dungeons take place INSIDE, they don’t have to have actually parts of the world map devoted to that. And even then, those maps are still the equivalent of kilometers across, which isn’t a small area. If you look at games like Anthem, they have really pretty environments, but the complaint is that they are barren. There is little that actually occurs out in the wild. Few settlements or areas to engage players.",
"I've played RDR2, and these are some of the techniques I noticed: - Use natural barriers to lengthen paths. If the shortest accessible path between points A and B is twice as long as the straight-line distance, then it's like they're twice as far apart. RDR2 often uses rivers and mountainous terrain to lengthen paths between nearby locations. - Break up the sight lines. Even if two locations are fairly close to each other, the player won't notice if they can't see from one to the other. RDR2's terrain tends to be pretty bumpy; there aren't many places where you can see for miles. - Use scale to provide the illusion of distance. Something small can seem further away than it really is. In RDR2, you can see the mountains to the north from much of the map, but because they're not really very big mountains, they can seem very far away. - Use large spaces strategically. There are several places in RDR2 where you can see a large open space that provides a sense of scale. But the views are carefully designed to provide an impression of the space going on further than it does, when the space beyond is actually screened or disguised by terrain. - Rely on the limitations of the screen. The screen can't show faraway locations in much detail and the player has no depth perception. The player has to rely on other, more easily manipulated cues to judge distance and scale."
],
"score": [
11,
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
gryrfp
|
why are computer languages the way they are? why are there so many languages?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs1y0b7",
"fs1yfp9"
],
"text": [
"There are advantages and disadvantages to various languages. The advantage of Java is that it's virtual machine means the same code can run on multiple systems. The disadvantage is that it isn't necessarily optimized for those systems. Assembly allows you the ability to potentially optimize your code perfectly to the processor it runs to the point not a single instruction or memory space is wasted. The draw back is that it'll take a long time to do such and it isn't comparatively easy to read the code The advantage of Perl is that it gives you many different ways of phrasing code that accomplishes the same task. The disadvantage is that anyone else reading your code may not be versed in the particular way you like doing things. Languages are written by different companies trying to appeal to different subsections of the coding population. They are naturally going to be different.",
"The main reason for so many languages is that some languages are really convenient for some types of coding and bad for others. For example, java is structured in a way that makes web deisgn more convenient while python is structured in a way that makes object-oriented programming more convenient. So you cant have one language that's perfect for all uses. And to your other question: i think the reason every language cant be perfectly intuitive or the same as regular english is because once you get more familiar with things, writing out long statements like in your example will eventually be more of a hindrance than a convenience. It's also probably more difficult to make a programming language that can handle the constant assumptions and context and etc. that we use to make spoken language feel so easy. Hence why we have to be precise in our coding or the computer wont understand what we want. What's simple for us isnt usually simple for the computer."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
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|
[
"url"
] |
[
"url"
] |
|
gs45tu
|
How do the new prosthetics work where people can seemingly control their new limbs with just their mind?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs2ssg0",
"fs39ycx",
"fs42c2q"
],
"text": [
"It begins with a special operations surgery where the bone is removed but the muscles are left intact. This is so sensors in the limb can pick on impulses sent to your muscles from Your brain. Most amputations aren’t preformed this way, however in the unlikely yet extremely lucky chance you are fortunate to lose a limb in a way that allows for the muscles to remain relatively intact, you can have a bionic limb that feeds back with tactile sensitivity and seem less control.",
"Step 1: Observe someone's brainwaves to see what lights up when they, say, extend their index finger. Step 2: Program the bionic index finger so it moves when that same activity in the brain is detected. Basically, your brain controls the prosthetic exactly the same way it controls your flesh-and-blood body, except instead of your nervous system detecting signals from the brain, the prosthetic detects those exact same signals.",
"There are two basic methods that can happen to achieve this. * Method 1: The cheating way (but also the more common way) You have to remember that the \"mind\" isn't really a thing. In a healthy limb, your brain sends signals down your nerves. These nerves touch your muscles and tells them to move, which moves your limb. Nerves aren't anything special though. You can kinda think of them like wires as they move electrical signals around. In the case of a prosthetic, we can read these nerve impulses and turn that into motion with a little bit of processing. In short, the brain and nerves send the signals still and instead of your muscles getting the signal, a computer tells a motor to run. I call this cheating because you aren't really controlling it with your mind directly - you are just replacing your muscles. * Method 2: The real way. This is not used as much, mostly because it is still very much in development, but you may have seen videos of this sort of thing. This sort of prosthetic uses signals directly from your brain. Not only do they replace your muscles, but they replace your nerves. The difference between (1) and (2) is that if your arm were to be chopped off, you could use both methods to restore movement. If you wanted to control the headless body of Agnew from the safety of your jar, you would probably use this method. The essence of this method is that, while very complex, we can read signals from your brain. If you were to be jar-bound Nixon, your brain could still make the signals that tell your body to take a step, even if you don't have the legs or spinal cord needed to execute that motion. Sensors on the head (or even directly implanted into the brain) can pick these signals up, and then just like the first method, we translate these into motion. The cool thing though, is that with enough training, you just have to think about making a movement. If I were to implant one of these devices into you, after a fair bit of training, you could get a robot arm to move just by thinking about it - as if you had a 3rd hand. As an example of this method, here's a pretty early video of this technology working with a monkey controlling an arm: URL_0"
],
"score": [
58,
13,
12
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"text_urls": [
[],
[],
[
"https://www.youtube.com/watch?v=sm2d0w87wQE"
]
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|
[
"url"
] |
[
"url"
] |
|
gs4y2e
|
What are RAW images and how do they differ from normal images?
|
I’ve listened to many tech reviewers and photo editors saying that RAW images are better and have been intrigued by it. Also what are it’s merits and demerits?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs2xa8z",
"fs2wtr9",
"fs32auc"
],
"text": [
"RAW images = what your camera sensor sees, normal images = what your screen shows. There are a few differences: A sensor doesn't really record colored pixels. Color is achieved by placing a filter in front of it - so some pixels will record only red light, some only green and some only blue. While your monitor does works in a similar way, generally there those \"subpixels\" are grouped together to full-color pixel units. This translation has to be done before an image can be shown. And there are other things that have to be done in between the sensor recoding an image and a monitor displaying it. A camera would typically remove image noise, correct white balance (basically, remove any tinting that the lighting of your scene might have), and a lot of other different things. RAW images don't include all of that and are taken directly from the sensor data, including more details about some over- or underexposed areas, that would just appear \"completely black\" or \"completely white\" in a processed image. That means that RAW images aren't really \"better\", in fact they themselves are much worse pictures than a processed JPEG. They just allow you the freedom of doing those processing steps yourself (and adjusting the parameters to your liking) to get an even better end result - assuming you and your software are more capable than your camera (which might make some wrong guesses about how you want your photo to look).",
"RAW format usually includes everything the camera picked up at the moment of taking the photo, so you have a lot of data to work with if you want to make a good picture out of it.",
"Raw Image is every bit of data the camera sensor captured. Huge files, but the maximum amount of information to play around with when editing. Normal Images (typically this means JPGs) are compressed, so they are much smaller and easier to share, but a lot of data has been lost so they can't be edited as much."
],
"score": [
34,
7,
3
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"text_urls": [
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|
[
"url"
] |
[
"url"
] |
gs6mu4
|
How does Google have the memory capacity to not only store every Google Doc ever, but also many versions of version history for each doc?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs381zl",
"fs38ufb",
"fs39rez"
],
"text": [
"Well, for one thing, storage is cheap. $10 for a terabyte. That's $10 for 1 trillion bytes of storage. Second of all, text takes up very little space. A novel in text format might be 200 kilobytes. Which means 5 novels fit in a megabyte. Which means 5,000 novels fit in a gigabyte. Which means 5 million novels fit in a terabyte. Which means you could store 5 million novels for about $10. Third of all, Google doesn't keep multiple versions of your document, instead they keep track of the changes you make. If you have a 5kb document and change one word in the middle, they don't store two 5kb documents, instead they store 1 5kb document and keep track of which word you removed.",
"I was talking to a friend in the tech industry some time ago, and he works mainly in information storage and retrieval. He mentioned that the big companies that produce hard drives and other storage (Seagate, western digital, etc) primarily sell their storage to companies like Google and Facebook. In fact, only some small percentage like 10% actually gets put on the general market -- the rest is snapped up by tech. So its super cheap storage, and they're buying a *lot* of it and spending huge quantities of money figuring out how to optimize storage and retrieval.",
"The size of the text document is minuscule compared to the space they use to store all video on Youtube or image in the google photos server. A letter in a test is in general on bye long but let's use 2 for uncommon Unicode character and storage space for the layout. & #x200B; Let's use the bible to get a well-kown document for comparison The king James bible has 3,116,480 letters so with 2 byes each you need 6,232,960 and let round it up to 7 million bytes or. A 4 TB NAS hard drive on newegg cost $100. The byes on a har rive is decimal so 4TB=4 000 GB=4 000 000 MB . The bible size is alos decimal so you could fit 4 000 000/7=571 428 \\~500 000. So you could fix half a million copies fo the bible on a $100 Harddrive. Lets say the server, redundancy increase the cost by a factor of 10 then the storage cost for the bible is 0.2 cent. So the size of the document on google docs is small compared to cheap hard drives and storing them is not a problem For comparison, a 5:13 minutes [youtube video]( URL_0 ) in 4K is 961 MB in size. IT is 961\\*1024\\*1024/(60\\*5+13) =3 219 429 byres per second. So we talk about the same amount of data as the bible every second in a 1 byte encoding. This shows that compared to video or images test is minuscule in size."
],
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61,
10,
6
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|
[
"url"
] |
[
"url"
] |
|
gsbuwy
|
What is an IP address, subnet, and gateway?
|
Please ELI5.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs4awxk",
"fs47fgc",
"fs47hds",
"fs4eacr"
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"text": [
"IP address is the unique number associated with one connection to the Internet - like the address on your house is the unique number associated with your home's place on earth. The gateway is the address you have to send things to get them out of your subnet and into the broader Internet. The subnet is a mask, which is used to calculate which addresses on the network are on your subnet, to which you can communicate directly, and which are not on your subnet, with which you must communicate through your gateway. Your subnet mask is a binary number starting with ones, and ending with zeros. It is applied over a binary representation of an ip address, and your ip address. The ones allow the number through the mask, zeros do not. Any address that matches yours when this is done is on your subnet. For example: 192.168.1.12 subnet mask 255.255.255.0 Is 11000000 10101000 00000001 00001100 11111111 11111111 11111111 00000000 So the result is 11000000 10101000 00000001 00000000 Which is 192.168.1.0 Therefore any address that starts 192.168.1.x is on your subnet Short version of subnet - a subnet is like the neighbourhood your house is in, and the subnet mask is a key to calculate who else is in your neighborhood based on your address.",
"I'd like to hear someone's more elaborate explanation but the way I was once explained them is as follows: An IP address is much like your own home address. A unique place on the internet that isn't shared with anyone else. You can share your IP with people or servers so they know where to send information too and from. A gateway is like if you lived in an apartment complex. You may share an address with someone but you don't want the information going to your mom's computer down the hall instead of your own. Your unique subnet (like a subdivision) would be your apartment number, so your neighbors don't get the information indetended for you.",
"This isn't a complete answers but it might help, [comic of how a browser uses the internet]( URL_0 )",
"An IP address is a way that a computer, or anything that has network capabilities identifies where it is. The address, like your home address analogy is a good one.. But it's not 100% accurate. More so: inside your actual house you can have all the IP addresses you want in the world. Inside your actual house are all of your private IPs... But you can't access the internet with them. Instead something called Network Address Translation (NAT) literally translates ALL of you private IP addresses into a single public IP which is provided by your Internet Service Provider. This public IP is truly unique and nobody else in the world has them.. And about once a month or so your ISP will assign you a new one.. Usually without you even knowing it happened. You have some other addresses that help make your network function.. For example.. Another special address that all networked appliances have is a Media Access Control Address, or more commonly known as a MAC Address. The MAC address is the physical address (so more accurate to your home address analogy because the MAC tells the network where the device lives.... Basically) the MAC is often referred to as the physical address and it can never be changed on a device. It's most frequently used for determining which device is asking the Default Gateway for an automatically signed private IP address. The default Gateway is usually called a router. The router is responsible for literally routing packets of data in and out of the network. At that point it basically functions as a literal gateway in and out of the house. When you are configuring your computer, the default gateway's IP address is the same as the routers address. In most residential applications, the router has a bunch of other functionalities though, such as handling DHCP, DNS NAT, interior packet switching, and usually they have a firewall built into them. Since you didn't ask about those, I won't go into it Finally, subnets. These are the trickiest thing to understand and to be honest I USED to be good at them but I've never used them in my work because we just VLAN segregate so why go through the trouble to do the math to actually subnet.. But that's neither here nor there. Subnets at the surface level are how you tell a computer or network device how many private IP addresses can exist on the same IP block segment. For example 255.255.255.0 subnet is considered a class C internal IP schema and can handle 254 private addresses on the same IP block (it would be 256 but the .0 and .255 addresses are reserved). 255.255.0.0 is considered a class B and can handle about 65,000 devices. Whereas a class A (255.0.0.0) can handle approximately 16.7 million devices. On a deeper level each IPv4 address is made up of for groups of 8 bits which coincide to produce a number.. For a total of 32 bits in the IP. If you're utilizing a class C. The default subnet is 255.255.255.0. Then let's say that your private IP is 192.168.0.2. 192.168 is the network that you are on..0 is the block segment, and .2 is your actual address in this case. If you know that you only want to have.. Let's say 16 devices on your IP block segment. Then you can do the math to figure out, based on the number of bits that are off in your IP.. To determine a new subnet to be on. (I say do the math because I can't remember the math.. Sorry) after that. Your subnet would become something like 255.255.255.12 and your new valid IP block would be 192.168.0.1-.17 because at that point .17 would be your broadcast IP and. 0 would still be your loopback (that's not really important for this scope) at that point the next valid range would be 192.168.0.18-254. and you have successfully subnetted your network. I hope that helps.. Feel free to ask me to elaborate more or to clarify something"
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9,
5,
4,
3
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|
[
"url"
] |
[
"url"
] |
gsce65
|
how does a monitoring software know the clock speed, data transfert etc. of components at any given time (CPU/GPU/disk/...)?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs4kngu"
],
"text": [
"Sometimes, the monitor will show what the component itself is reporting. The component knows it is using a certain amount of power, or is performing operations at a certain rate. The driver allows for the monitor to request and interpret this data. The monitor may also request data from the motherboard, which can control voltage or report bandwidth. Other times, the monitor will measure this with the help of the operating system, as it is doing its own monitoring. Some utilities may measure by testing the component, such as timing how long it takes to do a certain task. This is different from merely asking for a report, and takes more effort."
],
"score": [
10
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
gse1op
|
How does a High Speed Camera work?
|
I’ve been watching a lot of slow mo guys recently and love their videos but I’ve been really interested in the technology of how high speed cameras work. How do they capture such incredible detail at such a high frame rate? Also, why does resolution and exposure matter for the frame rate?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs4l07b"
],
"text": [
"The biggest hurdle is getting enough light. If your shutter is open for half as much time, you need to bring in twice as much light in order to see the same brightness. These cameras going at 10,000 fps need to bring in 160 times as much light as a regular camera, which means you're going to need a large high quality lens, and very good lighting conditions."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gsm1xj
|
Why are all songs deeper pitched on an FM radio than they are digitally on my phone?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs63ejc"
],
"text": [
"They aren’t, but you might be perceiving it that way because your stereo system has more bass response than the phone’s speaker or the earbuds most people listen to them with. Home stereos, car stereos, even your average boombox is better at sounding lower frequencies, which will give the same audio source a more “booming”, fuller sound than a teeny little speaker or headphone. ETA: plus, radio stations “compress” their audio output a hell of a lot so that everything is roughly the same volume and sounds very in-your-face, which can have a similar effect."
],
"score": [
8
],
"text_urls": [
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|
[
"url"
] |
[
"url"
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|
gsm3xf
|
What does hacking actually LOOK like? For example, what interface is the hacker using, what's their goal, and are they typing in a bunch of passwords like in the movies?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs633nk",
"fs67gmk",
"fs6xif2",
"fs62uyg",
"fs6wo68",
"fs6y2g7"
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"text": [
"Nothing like the movies. Most of it is writing a program at your leisure, depending on what you’re doing. It’s just exploiting over sights or weaknesses in a code or system. Very little is done in real time, and even that is more more mundane, just exploring directories for data you want, etc.",
"I'll try to explain in ELI5 fashion. Let's say I'm trying to physically break into a building I could have a bunch of motives. Maybe I'm trying to just rob the place (like when hackers are trying to steal data like credit card numbers for fraud). Perhaps the office has some specific info in there I'm trying to get (like if a government agency is spying on someone). Maybe I just want to vandalize the place (hackers who just cause destruction) or perhaps I just want to explore the building (hackers who like the challenge but don't do anything malicious). Just like breaking into a building people can have many reasons. Now let's talk methods Maybe I just try to break into the building by smashing a window (this would be a brute Force attack which is a program I write that tries a bunch of different passwords) Perhaps I tricked an employee and got a copy of his employee badge (phishing attacks) Maybe this badge works at other buildings too (a common thing to happen is people reuse passwords, then one site gets leaked and I can write a program that checks other sites to see if those same credentials work) I could also find a vulnerability with something protecting the building like shoving a pen in the lock will open it. Some people fixed their locks but I want to find the buildings that didn't (if there's a bug in a program, usually a patch is released but if a site didn't update then I can use the known vulnerability against them. If the door lock company doesn't even know about this issue it's called a zero day vulnerability... It means that someone discovered a bug and kept it a secret from the company so no one knows about it except the hackers.) I could also dress up as someone who works there, trick them into thinking I do, get let in and then unlock the backdoor so I come back at night (this is essentially what some malware does. It tricks you into downloading it and then gives a hacker access to the computer). Or maybe the people working there just give me what I want because they think I work there (social engineering) These are just some of the methods people use to hack. There's a lot out there and some way more complex. But this is a quick basic guide. One thing though for sure, no one is sitting in front of their computer with a mask and gloves to hide fingerprints like the movies.",
"From the purely visual side? Your average hacker is almost certainly using a command line terminal to do most of the work, so it's probably a lot like what you are picturing, but without the intense music and with less flashy visuals. *Not including social engineering, which is a major part of actual attacks*, most hacking can be boiled down to 3 activities: * Manually investigating: typing and reading stuff at the command line (most hacker-esque part). * Finding or coding tools/scripts that detect and exploit weaknesses: combination of command line, text editors and some kind of online chat or reference (preferably with tight anonymity if you don't want to ever be traced). * Waiting for the tools to run: have a second monitor with command line output and play some video games (\"sec I'm just downloading the mainframe\") It's much easier to write scripts and do things in a controlled and predictable way on the command line, and the tools that you'll want to use probably don't have GUIs (with the notable exception of advanced tools that have a **lot** of information and are painful without, such as network sniffing tools, decompilers and debuggers.) Most hacking is going to involve gaining entry to another system or server, and you won't have the luxury of being able to set up a remote desktop (unless you are hacking via an incorrectly secured remote desktop service) so you'll be limited to a remote command line there (SSH). Also, if you can't use the command line, you probably don't have enough knowledge to do any practical hacking, it's mostly about knowing about how the system and software actually works, and therefore how you can gain access in an unintended way. The alternative is just getting someone's password, which is much easier via phishing or other social engineering, but that's boring (although what you do once you have it is more interesting). EDIT: I'd like to tack on that I think there should a far more serious level of education in computing from a young age nowadays, it's not rocket science and you use computers everyday. Plus, this was mostly about remote hacking, which is what most people would think about (some kid in their bedroom hacking into FBI computers) but another incredibly fun and interesting side is hardware hacking and reverse engineering. Probably the best-known example is hacking games consoles. The challenges here are far more diverse and interactive, much safer and not massively illegal like remote hacking.",
"It looks absolutely nothing like the movies. What it looks like depends on what you're trying to do",
"There's lots of good answers here, so I won't add to the list. I will, however, give you a place to go where you can feel like you yourself are a hacker. [Go here. Hack the world.]( URL_0 ) ^((just go mad on your keyboard))",
"Hacking is a very broad term. Depending on what the goal of the hacker is, the process can be very different. Like mentioned elsewhere in this post, at the end of the day, all hackers are looking for vulnerabilities in another's system. Some examples of hacking would be: Finding a special edge case in their code which allows you to get information you should not normally be able to access. By inputting certain code into search bars on websites like Amazon/Ebay/ URL_0 , it may be possible to actually execute the code on the companies computer (which they usually don't want for obvious security reasons). Realizing there is access to a computer in a way that the user of the computer did not intend to have open. Upon connecting to the computer, the \"hacker\" tries to remain unnoticed as he collects information about the computer, or even leaves himself/herself an opening on the computer so that only they can get in. Using keyloggers or special software that runs through thousands of passwords per second to \"legally\" access another user's system while appearing to actually be that user. What does hacking look like: Like I just stated above, there are many forms of hacking, but the most common interfaces one would use would probably be a terminal/command line, which is a text-based environment where you can enter commands to control your computer (e.x. Typing in a command to copy a folder from one location to another instead of just visually copy and pasting it to the new location), and a text editor where the hacker can write and test malicious code. Typing in the movies: Usually hackers are not trying to manually type passwords to try to guess them, as mentioned earlier, this can be done by computer software and would take you more hours than there are stars in the sky to try every possible password. All of the speedy typing seen in movies would really be the equivalent of someone who knows how to use a terminal/command line very effectively. Hope this answers your question :)"
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|
[
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[
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|
gsnxfh
|
Why use a suppressor for a weapon?
|
Obviously guns are loud. VERY loud. In movies we often see people using suppressors to make their guns virtually silent but obviously this is a completely fictional trope. It is my understanding that even with a suppressor a gun that is fired is still extremely loud, so why use them at all? Is there any other practical purpose other than making a weapon a tiny tiny bit quieter?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"As usual, the answer is more complicated. With the ar-15 shooting .223, the gun is still VERY loud. an AR shooting .300 blackout, its damn near silent. With most pistol caliber firearms, (handguns, MP5s, etc) it can be very very quiet. With 22 rimfire, it can be damn near silent. Why do it in a military role? They often help reduce the need for ear protection. They reduce muzzle flash (giving away position, especially at night). They make it harder to locate direction of shots. (important to not be shot) Even loud firearms are quiet at long range. With quieter firearms you can be pretty covert in tactical situations.",
"It reduces the audible decibels to the human ear. This reduction means there is a much smaller chance of hearing damage. Obviously, proper ear protection is still suggested.",
"Another use of firearm suppressors/silencers is to reduce or eliminate the muzzle flash, the bright explosion from the barrel when the weapon is fired. For snipers behind enemy lines, going unseen is often crucial. Firing a weapon without reducing the muzzle flash will make it very easy for the enemy to locate the sniper, complicating the sniper's retreat.",
"Sound gets reduced quickly by distance. Even if the shot is still loud enough to require hearing protection where the shooter is, a suppressor can make the distance that it will hurt ears, annoy people, or be audible at all by a lot."
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[
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[
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gsnym8
|
How do scientists search for stars and galaxies millions of light years away?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fs6ic3r"
],
"text": [
"You must have heard of the HUBBLE Space Telescope. Launched in 1990, orbiting Earth at around 560 km altitude, with it's 2.4 meter objective, it's four main instruments can observe in the near Ultraviolet, visible and near infrared spectra. Hubble can see the dimmest and faintest objects out there of any telescope we’ve ever built, and can do so to wavelengths entering the near infrared. In theory, it could pick up traces of once-ultraviolet light from objects from when the Universe was just 400 million years old. But Hubble can not verify precisely just how far the observed galaxies are. For this purpose, astronomers need to measure the precise wavelengths that the emission and absorption features from a galaxy are, and for this, they use ground-based spectroscopy. And that in turn means that they turn to the largest telescopes ever built, such as the 10-meter Keck telescopes in Hawaii, which houses the newly-installed MOSFIRE spectrometer, perfected for infrared observations. Talking about distances, the latest find - galaxy EGS8p7, observed and measured by Hubble just a few months ago, was confirmed to have a red shift of 8.63 - the highest redshift of any galaxy ever, meaning that its emission lines are a factor of 863% longer in wavelength today than when they were emitted. The light from this object comes from when the Universe was just 588 million years old, or just 4% of its age. [When galaxies are moving away from us at high speeds, it causes the light to redshift, by stretching its wavelength. The energy of a photon is defined by its wavelength, so if the wavelength is stretched due to the doppler effect, it drops to a lower energy and hence becomes red in color. For a galaxy whose light was emitted more than 13 billion years ago, that redshift is so severe that the ultraviolet light emitted by its atoms gets shifted all the way past the visible light portion and into the infrared. Shift that light some more, and even the Hubble Space Telescope won’t be able to detect it.] All records are meant to be broken. The above record won’t stand for long! Another newer, bigger telescope is being built. Known as the James Webb Space Telescope due to be launched in 2018. This has a 6.50 meter objective offering un-precedented resolution and sensitivity. it should not only dwarf the light-gathering power of Hubble, it is designed to probe farther infrared wavelengths than Hubble has ever dreamt of. Unlike Hubble, which can reach wavelengths of about 1.5 microns, James Webb can go all the way out past ten microns, meaning it can see all the way back to the first galaxies and potentially beyond, even all the way back to the first stars. [Source]( URL_0 )"
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