q_id
stringlengths 6
6
| title
stringlengths 4
294
| selftext
stringlengths 0
2.48k
| category
stringclasses 1
value | subreddit
stringclasses 1
value | answers
dict | title_urls
sequencelengths 1
1
| selftext_urls
sequencelengths 1
1
|
|---|---|---|---|---|---|---|---|
i9xbn2 | why bathroom scales give an initial reading that is about 1.5kg higher than second and subsequent readings? | This has happened to me consistently with 2 completely different brands of bathroom scales. I store the scales vertically when not in use. | Technology | explainlikeimfive | {
"a_id": [
"g1i30f6"
],
"text": [
"Are you zeroing the scale every time first? Whenever you set it on the ground after storing it vertically, you're supposed to step on it for just one second until it wakes up, then step off and wait for it to show zero. Then step on and you should get a consistent, accurate reading."
],
"score": [
10
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
i9xzyf | Why do some appliances/devices require 6 AA batteries instead of 2 C batteries? | Or whatever the equivalent would be. I'm not a battery guy obviously. | Technology | explainlikeimfive | {
"a_id": [
"g1i8uem"
],
"text": [
"AA, AAA, C, and D batteries all have the same voltage (1.5 V) but have different amounts of total charge and different maximum current. If you use 6 AA batteries in series you can get 9 volts but with more charge than a single 9V battery. With 6 AA batteries in parallel you can likely provide more current than 2 C batteries without overheating the batteries."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
i9zmz0 | How would you explain Cloud computing to someone who has no knowledge about it? | I'm trying to explain to my grandparents but it's really tough because they can't seem to understand the complex terms. Any advice on how to break down Cloud in layman terms using an analogy? | Technology | explainlikeimfive | {
"a_id": [
"g1ijcge"
],
"text": [
"The Cloud simply means: someone else’s computer. You are just connecting to someone else’s computer to do whatever you were going to do."
],
"score": [
35
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ia13se | Why Factorio doesn't burn everyone's cpu? | Today i Fired up factorio again and i loaded up one of my older saves. And then, i had sudden realization. I know that object collisions are very taxing and take a lot of processing power. Then i zoomed out and watched Factorio handle more than 10k objects moving and colliding with each other on my screen and my cpu was resting at 30%. how is that even possible ? | Technology | explainlikeimfive | {
"a_id": [
"g1iwv2h",
"g1j7qn7",
"g1jlqmf",
"g1kaazt"
],
"text": [
"The processing required for object collisions really depends on how optimized the game is. Since factorio is a 2d game and the majority of interactions are locked to conveyors, they can be extremely optimized and hardly use any cpu.",
"Factorio treats items on a compressed belt as a single entity. URL_0",
"Factorio is developed by programming perfectionists. They optimized everything they could think of, in the case of collision, once two objects collide on a belt they become a chain. In a chain you only need to consider collisions with the extremities. As most of Factorio gameplay involve having backed up conveyer belts, this virtually trivialize \"collision\" detection. Drones flying around are more amount to compute, and that's why they for in straight line and don't collide. Concessions have been made to ensure performance.",
"To put it bluntly, most games are coded horribly inefficiently. Consider a game with 1,000 different 3D boxes colliding. Boxes are one of the simplest shapes to test collisions for - you basically just need to check if the corner of one box is inside a second box. To check every box against every other box to see if any collide, that's `1,000 * 1,000 = 1,000,000` different tests. Now, that sounds like a lot, but it's actually not *too* bad, because modern CPUs can perform tens of millions of calculations per frame while running at a cool 120 FPS. But what happens if you were to, say, go up to 10,000 boxes? Suddenly it's `10,000 * 10,000 = 100,000,000` Oops, 10 times the boxes added *100 times* as much work for your CPU and now your PC has started to stutter. That's called an \"N-squared\" algorithm, because the amount of work goes up by the square of the number of objects. Those are bad, and you should avoid them. There are a *lot* of tricks you can do to do better than checking every single box against every other box. For instance, Factorio isn't checking every moving item against every other item. Instead, it only checks each item against the item in front of it. If you have 1,000 items on a belt, that's only 1,000 checks, not a million. Except -- Factorio *also* knows that if items are already next to each other (compressed, in game lingo), it also doesn't need to check them for collisions because they're already colliding. So it skips them entirely -- only separate clumps of items on the belt are checked. So you could have a million or more items on a belt, and yet the game is only checking for a few thousand collisions at any moment. That's the exact opposite of what we saw before! Factorio is full of these kinds of tricks, and that's because it was made by a bunch of programmers who have a deep understanding of both computer science and the intricate details of how their own game works. Very few other game developers show both the ability and willingness to optimize their games to that degree."
],
"score": [
31,
22,
10,
6
],
"text_urls": [
[],
[
"https://www.factorio.com/blog/post/fff-176"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
ia2bqs | Why do traffic cameras begin to malfunction? Could they not just be set on a standardized timer to offset the blinking malfunction indicator? | Why do traffic LIGHTS (not cameras) begin to malfunction? Could they not just be set on a standardized timer to offset the blinking malfunction indicator? 4 way stops are horrendous when considering traffic density for certain times of the day. Why would a short-term timer not work? | Technology | explainlikeimfive | {
"a_id": [
"g1je8jy"
],
"text": [
"I think you are talking about traffic signals not traffic cameras. That blink when they malfunction making the intersection into a 4 way stop. Originally, traffic signals were just on timers. 50 seconds for each light, then move on to the next (or whatever time). But as our technology got better, we began to computerize everything, and that has decreased traffic. Think of a major intersection. You have a 6 lane road intersecting with a 4 lane road. In the morning, the 4 lane road has a lot of cars feeding into the 6 lane road. In the evening, traffic flow is reversed. A simple timer cannot accommodate this. So a computerized traffic signal is able to be programmed with traffic patterns so that in the morning hours it favors getting traffic off the 4 lane road, and in the evening it favors getting traffic off the 6 lane road. If we were to go back to simple timers, it would make traffic very bad compared to what we have today. And the rate of failure is very low for how many hours they function. Never mind that every time there is a power outage with a simple timer, someone has to go out and re-set it to the correct time."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ia2n36 | () Why are there so many "sexbots" on Instagram? What makes them profitable? | Technology | explainlikeimfive | {
"a_id": [
"g1jldgs",
"g1jm02y",
"g1k2uf0"
],
"text": [
"Low ongoing cost once the system for automatically creating them is set up. Difference in cost between running one and 1000 is minimal. So if you can make one, why not make 1000? Even if each one only generates the equivalent of 10 cents of profit a day, that's 100$ a day.",
"They are scams. They promise nude pics or sex shows and then ask for your credit card to 'prove' you are of age. They can then rip you off for whatever they want. The reason it is profitable is because a single person can run hundreds of these scams and there is very little stopping them from just starting up immediately again if they are banned. International laws are difficult, so if they target outside their home country, what can any of us do? On top of that, the obvious nature of these scams act as a passive filter because only gullible or desperate marks are willing to try these sorts of things, and they are more likely to pay up or not actively try to report any issues. They also can use these scams to get intimate photos of people and then blackmailing them for more cash, or they can use it to trick you into giving away personal info they can exploit or sell. I think in the case of these sex bots, however, the main focus in automating them to lead you to the 'credit card for age verification' scam.",
"People are dumb. They fall for phishing attacks all the time. Seriously, do not under estimate how many people will fall for these things because they were never educated on technology."
],
"score": [
189,
71,
15
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ia37zl | Why are infantry still relevant in modern war despite all of the advanced weapons available to militaries? | Technology | explainlikeimfive | {
"a_id": [
"g1jngj4",
"g1jqzdd",
"g1jn0db"
],
"text": [
"Infantry is slow and unprotected, but highly versatile and can traverse complicated terrain like cities and the inside of buildings. Infantry can detain or kill individual persons with high precision. This is important because if you want to control an enemy nation, you must seize rather than destroy key cities and infrastructure. The goal of war is not destruction, but control. Infantry is also relatively cheap, which is important in war: modern wars are economic contests just as much as marital contests.",
"What is the ultimate objective of war? You get to tell someone else what to do, or not do. Simple as that. Who tells you what to do or not do? The police, your parents, a judge, a ballif, etc. You ever had an airplane tell you what to do or not do? Stewardesses yes. But an airplane flying at 50,000 feet? Of course not. Same with a tank. Same with a battleship. At the end of the day it is people with guns standing right in front of you telling you what you need to do, or not do, that actually accomplishes the task of getting you to do, or not do, something.",
"All the advanced weaponry in the world won't help you hold ground. A fighter jet lobbing air-to-ground missiles or a gunship BRRTing its way to glory are transient weapons -- a lot more so than boots on the ground. They go in, they do their job, and they leave. Infantry are a lot closer to the action, so they'll have an easier time of holding territory."
],
"score": [
8,
5,
4
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ia46ch | Why can't we connect two computers directly using an Ethernet cable ? | Technology | explainlikeimfive | {
"a_id": [
"g1l0azv"
],
"text": [
"You can. Obviously you can't connect to the internet that way, so it has a limited use. But for example for gaming this is still quite common. That's what people are doing at a lan party, everybody connects their pc to each other and everybody can play together, even without any connection to the internet."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ia53rt | How does frequency turn into sound? | Human ears can hear 20 - 20000hz frequency, if you were to listen one of those [frequency test videos]( URL_0 ) they go from very low pitch to very high, then how exactly do these sounds represent different instruments in songs or voices? I messed around with with EQ in DAWs and they depict that different instruments hit on different frequencies in the spectrum yet they sound so different from the video? | Technology | explainlikeimfive | {
"a_id": [
"g1kf921",
"g1kfm4d",
"g1kgago"
],
"text": [
"It’s not meant to represent anything or any sound in particular, it’s bunch of different frequencies being played in sequence, it’s pure tones that you don’t really hear normally, music instruments don’t sound like that, they sound like many different frequencies played together. However pure pitches like this can be useful to test how well your stereo or your hearing works on various frequencies Side note: YouTube can’t really reproduce sounds above 16000 Hz or so, so it’s not really a good test anyways",
"Frequency is not a thing by itself is just how many times something happens per unit of time. The frequency of your birthday is 1 per year. Hertz is just cycles per second. Sound is a pressure wave in the air and if has 5000 cycles per second it had a frequency of 5000hz. So you do not turn frequency into sound, the sound is a pressure wave in the air, frequency is a description of how many cycles per second a pressure wave has. You compare it to waves you create in water. If you have a large container and move a ball up and down in it you create the wave. Move the ball up and down twice per second and the waves have a frequency of 2 Hz. The frequency is a description of the wave not a thing in itself. So you do not turn frequency int sound, the frequency it one way we describe the sound. You can compare to how you can describe fabric by the thread count in the number of threads per inch. That is like frequency but for distance instead of time. You do not make fabric from thread count the same way does not make sound from frequency, both its way to describe fabric and sound. Any periodic wave can be broken down into simple sin waves and the spectrum of a sound is a representation of what sine waves it is made up off.",
"Well a test frequency usually uses a sine wave. This is a very basic wave where the characteristic shape is fully described by a single frequency. Almost all sounds - voice, instruments etc - are a combination of various frequencies at different amplitudes (aka loudness). Even if a (say) guitar makes a note with a fundamental frequency (the loudest note), it also produces other sounds at other frequencies (called harmonics). This makes a guitar \"sound\" like a guitar. This is why different instruments and voices singing the same note have different qualities."
],
"score": [
5,
4,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
iabnr9 | How do studios remaster productions in 4K/High Definition if they were filmed 10+ years ago? | Technology | explainlikeimfive | {
"a_id": [
"g1mhuf4"
],
"text": [
"If they were shot on actual film they can rescan the films. Film itself is a physical medium, and just like scanning a sheet of paper, you can scan it at whatever resolution your scanner will allow. Naturally it can only scan what's present, so if you're scanning an old Super 8 or 16mm film, you may find that all the pixels you're scanning to aren't adding much detail. But for 35mm or certainly 70mm, there's so much information there that you can scan in enough for high resolutions. For digital films, most will have been originally filmed at higher resolutions even if the only time those versions ever got used was in cinemas. It wasn't until digital cameras became on par with the quality of film cameras that they received widespread adoption,so the problem of old films being shot on an iPhone 2 quality early digital camera doesn't really exist. That said, Avatar was only ever filmed and \"mastered\" at 1080p. It looks amazing, though, because each frame is so beautifully clean (and, in some cases, more or less entirely CG)."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
iaclpe | why are the graphics of new games that were made from 2018-now is so bad when it's set to low? Why can't it look like a 2014 game set on ultra. | If I can play a 2014 game on ultra settings and there's this new game that came out this year. Why does it look so terrible when it's set to low? Can't they improve it to make it look like a 2014 gane set on ultra? Same graphic level. Nothing fancy | Technology | explainlikeimfive | {
"a_id": [
"g1mqxuo",
"g1mr3oa"
],
"text": [
"Graphics don't improve THAT much in 4 years. You're asking quite a bit considering Moore's Law doesn't apply anymore.",
"Because textures, lighting, shaders, and the number of pixels are what mainly change when switch from ultra to low. A 2014 game has lower resolutions in all of the, there fore it's easier to run. With newer games the detail on ultra compared to ultra from 4 tears ago is quite large, even if we're getting to the point of diminishing returns"
],
"score": [
6,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
iad5qu | PC Tech Pricing | Why do new and more powerful graphics cards and proccesors cost so much more? Do they actually cost more to manufacture or is it the same materials as cheaper parts just rewired for more performance and power? Like the most powerful parts from a few years ago go down drastically in price? | Technology | explainlikeimfive | {
"a_id": [
"g1n2bbo",
"g1n7pfv"
],
"text": [
"I believe the slow price creep on high-end GPU and CPUs has to do with the expansion of the enthusiast market as well as increased manufacturing costs. When I started building PCs around 8 years ago, the best consumer GPU you could buy was the GTX 680 ($500) and the best CPU was the i7-3970X ($999). Nowadays Nvidia can sell you a RTX 2080 Ti ($1200) and AMD can sell you a Ryzen TR 3990X ($3990). It seems like the enthusiast market has grown significantly, and the massive increase in resolutions (1080p -- > 4K/ultrawide) and refresh rates (60 hz -- > 240 hz) has created a need for much more powerful hardware in the enthusiast sector that has been ultimately filled by taking higher-end chips that used to be designated for workstation or server use and marketing them to enthusiasts. AMD Threadripper, for example, was originally essentially two Ryzen CPUs in one package on a server-esque platform. Nvidia also created the 980 Ti by taking a Quadro card targeted at professional usage and halving the VRAM, and have been doing the same ever since. So part of it is that the marketing strategies have shifted and it has made more and more sense to market to the small minority of enthusiasts that really want the cutting edge of performance. Manufacturing costs have certainly gone up massively due to the continuing semiconductor shrink. Every successive generation brings new challenges as transistor density continues to go up exponentially following Moore's law. But the difference is mostly in marketing, because the CPU and GPU mid-range have been holding strong at ~$200 and ~$300 respectively for the last decade, and it's very clear that chipmakers can and are targeting a certain price for each successive generation for the real money-makers, even as flagship prices have gone up.",
"R & D is a big part of the cost. It takes large teams of highly payed professionals using lots of very expensive equipment years to get to the product to market. All that has to be made back on sales. With older stuff, that investment has already been paid back."
],
"score": [
6,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
iage4a | How is it possible for a phone to be charged with a charging pad and not a cable? | Technology | explainlikeimfive | {
"a_id": [
"g1nvc1l"
],
"text": [
"Do you mean Qi wireless charging? Its a magnetic field. Magnetic fields can pass wirelessly through the case and when a magnetic field is turned on it pushes on the electrons. All you need to do is switch the magnetic field back and forth and it can induce a current. It’s a transformer cut in half."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
iahdod | How come the technology used for household batteries (AAA, AA, etc.) has been the same for decades while we’ve made so much progress in other areas? | Technology | explainlikeimfive | {
"a_id": [
"g1o6vvq",
"g1ok5b4",
"g1ocj98",
"g1oee2z"
],
"text": [
"Because they work really well. The technology behind toilets is the same. Super old but gets the job done. Besides some advancements have been made. Many devices that use to require alkaline batteries use lithium ion now.",
"The technology inside an AA battery has changed quite a lot over the last few decades, what had stayed the same is what that battery outputs. An AA battery is a standardised item - that means you should be able to take any AA battery, plug it into any device that needs an AA battery, and have that device work. This means that every new TV remote is designed to work with a standard AA battery, and every manufacturers AA battery is designed to fit that standard. If we want to change that standard into something different and better, we no longer have an AA battery, we have something new and incompatible - which do exist, as there are a vast array of different batteries out there, things like different sized equivalents to the AA (AAA, C, D, etc), button cell batteries (LR44, CR2032, etc), high power cells (CR123, CR2, etc) and various types and sizes of rechargeable cells (18650, etc). Underneath the skin however, AA batteries have been being upgraded over time - different chemistries have allowed for much longer lasting and stable single use batteries as we have developed from zinc carbon to alkaline battery chemistries, and into more modern lithium ion. We have also had a revolution in rechargeable chemistries from early battery types with poor capacity that would discharge in a few weeks even unused, to modern options that with equal the capacity of a single use cell and that will hold charge long enough to be sold ready to use without needing charged first.",
"The tech inside the battery has advanced. The shape just is standardized and therefore gets used even for the newer tech",
"There are some moderizations. Lithium ion as was mentioned above, Batteries you can recharge, etc. But sometimes things are already perfect. It's like the wheel. It has improved a little bit. Using inflatable tires to reduce how it handles bumps, making them out of rubber instead of stone or wood. You can try to improve things a bit, but there is only so many times you can reinvent the wheel"
],
"score": [
21,
7,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
iajwxj | How does an iphone mic pick up your voice, but not your friends voice coming out of the speaker, on facetime? | Technology | explainlikeimfive | {
"a_id": [
"g1p0kxg"
],
"text": [
"The phone knows what sound is coming out of its own speaker. It can intelligently prune that out from the microphone input."
],
"score": [
19
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
iakigk | How does someone get crazy drone footage flying super high, across town, and through buildings? Isn't there range and lag issues? | [Like in this post,]( URL_0 ) they are flying all over the city and through doorways and windows without hitting anything. I can barely even get a smooth video on my phone when I'm in the same room as my WiFi router. How do they do that? | Technology | explainlikeimfive | {
"a_id": [
"g1p4zbp",
"g1pdix2"
],
"text": [
"There are sometimes lag issues and latency. But skilled pilots can handle it (to fly in a lot of public spaces you’re actually supposed to get a certification). For connection issues yea for cheaper drones. But some High end ones I know are able to handle half a mile to a mile in distance, and I’d imagine soem can go even further. At the end of the day it’s similar technology to radios/wallow-talkies at the basics, and portable ones of those can be rated for as far as 5 miles at the high end. So the answer is most normal consumer ones (like a couple hundred bucks) you’d probably run into some issues. But there are high end ones that cost thousands.",
"Range is not a issue. 2.4Ghz which many use is good for a mile or so. Bigger drones like my airplane use 900Mhz which is good for a dozens of miles while the video signal at 1.2Ghz is good for around 10-20ish miles. The further I've ever gone is 3 miles. Flying high is easy. Radio waves love to travel line of sight so 1,000 feet is just as easy at 5,000 feet. When you see drones flying down mountain ranges and through valleys they are using highly directional reception antennas like multi turn Helical or Patch antennas sometime with tracking to where it automatically follows the drone. IB Crazy is the OG fpv antenna designer and has some great videos. URL_0"
],
"score": [
11,
5
],
"text_urls": [
[],
[
"https://youtu.be/88L5Dv-mwQc"
]
]
} | [
"url"
] | [
"url"
] |
ial8h6 | Why can't a secure, hard-to-undermine online voting system be developed for elections? | Technology | explainlikeimfive | {
"a_id": [
"g1pa4j7",
"g1qacgk",
"g1p9ltq",
"g1r7xhd"
],
"text": [
"It's a matter of risk. You could make an online voting system that is harder to breach, but a single breach could lead to vast manipulation. Our current systems might be easier to breach, but the impact is smaller and more easily caught.",
"Voting systems need to solve four problems. 1. Every person of voting age gets one, and only one vote. 2. Every vote must be accuratly counted and reflect a vote of an actual person. 3. It must be impossible to tell how any given person voted. 4. Everyone with a stake in the election must be sure that the system works correctly and produces valod results every time. We have more or less solved all these things with paper voting. Digital voting has not gotten there yet reliably, and should not be used for elections that are important.",
"Because humans are good at many things, especially making mistakes. Making an online voting system is subject to human error, no matter how good people make the system.",
"There is a fundamental problem with electronic voting that can't be solved, even if we manage to make it reasonably secure. Transparency. Since every citizen is affected by the outcome of the vote, everyone needs to be able to trust in the vote having been conducted in a fair manner. Problem with electronic voting is: To make it reasonably secure, so much advanced cryptography/math is involved, that even most IT experts won't be able to fully understand it. Most \"normal\" people simply have no chance grasping even the basics. Electronic voting demands that the vast majority of the population simply \"have faith\" in the expertise and fairness of a very small tech elite. That, I find a highly unreasonable demand. Paper based voting on the other hand is simple. In my country everyone can volunteer in the counting of his/hers municipalities votes. At least for your municipality, you know that you and your peers counted correctly and fairly. After the vote, you can check that the correct counts have been reported to the canton (state) and federal level, because these are published for everyone to see. And you can assume that all other municipalities did it right, because they too rely on the volunteer system."
],
"score": [
9,
7,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
iao63t | How does the OS virtualize memory? | Also curious about how virtualization works in general -- stuff like virtual machines, containers, etc... Thanks! | Technology | explainlikeimfive | {
"a_id": [
"g1psrc1"
],
"text": [
"You are mentioning two different things: 1. Virtual memory - functionality built into the OS so that it can use hard drive space as working memory when RAM memory is low. This is inefficient and VERY slow, but allows processes to continue running instead of crashing albeit with decreased performance. 2. Virtual machine - this is a program that emulates an environment of a certain hardware type so that programs written for that hardware can run within it. An example of this are console emulators that run on a PC. Console games are made to \"think\" they are running on compatible hardware."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
iattnj | What goes into rendering a font? | There seems to be a lot going into just displaying a font on a computer screen, e.g. Cleartype. What other things go into rendering a font? | Technology | explainlikeimfive | {
"a_id": [
"g1qubn2"
],
"text": [
"When rendering text, it first needs to be split into chunks based on left-to-right and right-to-left languages. This is to make sure that you can mix both kinds in a single paragraph, without some words appearing to be backwards. One library which can take care of this is FriBiDi. Next, the application needs to process Unicode groups. For example, emojis now support skin tones, which are a second Unicode code point following the emoji which converts it into a slightly modified version. The text contains the symbols < smiling emoji > < dark skin tone > and is converted into a single font glyph < dark smiling emoji > , if the font supports it. Another example are modifying characters, which are how some people get those usernames with a huge tower of random accents above some letters. The text < letter a > < combining caron accent > < combining caron accent > < combining caron accent > < combining caron accent > can't just be rendered in a line, another function positions the accents above the previous letter, again based on how the font specifies it. This can be done with the HarfBuzz library. Next you have to measure your text. Letters are typically placed along the baseline, which is an imaginary version of the line you had to write on in school. The font specifies how much further to draw each character after the previous. You have to measure the text length to perform word-wrapping, or to justify or center the text. Now you can actually start rendering. You pick your start point (origin) and start drawing letters. Each symbol (glyph) has a certain bearing, which is the vertical and horizontal offset where you start drawing it relative to the origin, and an advance length, which is how far to move the pen. Accented characters can be drawn at a relative position from the previous glyph instead. This can be done with the FreeType library. Another complication is kerning. For example, the letters AV overlap a little, there is a special width adjustment just for this pair. Without kerning, the gap would look unreasonably large (like V A). The r/keming sub is supposed to showcase issues like this, but lately has had other content posted as well. Since most fonts are outline fonts, you first have to convert this outline to a bitmap off-screen. This is similar to the pen tool in Photoshop. You have to scale the outline based on your font size and align the shape to the pixel grid to prevent it from appearing blurry. This is called hinting. ClearType is Microsoft's patented version of subpixel hinting. Once you have the bitmap for each glyph, you can just copy it to the screen location determined above. There are also recent advancements with color fonts (which is how emoji fonts can give you colored emoji outlines, even if your text color is black), and variable fonts, which let the designer modify the font parameters, e.g. the thickness of letters."
],
"score": [
21
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
iaua3z | How do noise cancelling headphones work? | Technology | explainlikeimfive | {
"a_id": [
"g1qsl32",
"g1qtsy1"
],
"text": [
"Do you know how sound is a wave of energy? Well imagine a flat horizontal line, representing a sound wave. When it’s flat, let’s say there’s no energy so we hear silence. Now imagine a sound, and we see the sound represented as big hill-shaped bump of energy appear on our wave. Now imagine the mirror opposite of that bump of energy- a big valley shaped bump of energy the same size as our hill. It’s the negative version, or phase. If you were to play that wave on a speaker, he positive one would tell the speaker diaphragm to move one way, and the negative one would tell it to move the other way. So If those two waves overlap, they cancel each other out, and we’re back to a flat line, silence. What Noise cancelling headphones do is listen for external noises. They have microphones on the outside, and when they hear a noise they immediately generate the opposite wave of the noise they’re hearing, and pipe it into what you’re listening to, which cancels out that noise. This works best or is more noticeable with droning noises that are steady and ongoing- like airplane cabin noise, or a fan or air conditioner.",
"Noise cancelling is done by either active noise cancellation or passive noise cancellation. Passive noise cancellation is using padding or other insulation to block out the external sounds providing noise cancellation. Active is more complicated, as sound waves travels in the air it creates regions of air fluctuations. These can interact with other sources of sound to create interference. This can result in sound increasing when the different sources are working together or it could cancel each other out. Active noise cancellation tries to calculate the wave of the noise reaching your ears and actively opposes it to cancel out external noise."
],
"score": [
10,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
iaw4hy | Recursive and Iterative DNS lookup | I can't get the grasp of the concept! they all sound the same | Technology | explainlikeimfive | {
"a_id": [
"g1r2x85"
],
"text": [
"Recursive - the dns server you contacted will search through all the resources it has. Iterative, it looks in its own list and tells you where else you can check. Imagine if you called a school secretary and said “I am looking for Joanie Cunningham, she’s in grade 9”. Interative: the secretary answers “she’s not here in the office. Try calling Mr Jones, Ms. Bennedetto and Mr. Wong’s class lines. “. Recursive: “she’s not in the office, but I called the classes, she is in Mr. Wong’s class right now. Do you want me to put her on the line?”"
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
iazfyj | I understand that, in computers, a '1' can be represented as a pulse. Be it light or an electric charge. But how us a '0' communicated? | How does a system differentiate between a 0 and a gap between two 1's? Like, if you have the strung '11010001' flashed onto a wall by an optical cable, how would this look if we could slow it way down and how does a receiving device interpret this? | Technology | explainlikeimfive | {
"a_id": [
"g1rnlju",
"g1rpp1f"
],
"text": [
"Clock timing. You are likely familiar with GHz rating of processors. This is the speed at which it operates and modern processors can \"throttle\" up or down within a range as needed. This will all fall back to a quartz clock on the motherboard that oscillates with a very definite speed. Just like a metronome or a good drummer sets the beat for musicians, this quartz crystal sets the beat for the computer. Knowing how many beats each bit should take, it is able to know how much time has past and if a transistor is open (0) or closed (1).",
"It isn’t. Typically, they’re all the same length. A high value (usually 1.8, 3.3, or 5.0 volts) means a “1”, and the low value (usually 0.0 +/-0.3 volts) means a “0”. So the computer sends the low value to mean a 0. If there are two “1”s it will just be twice the length of any value. In others, 2 “1”s would take 2 clock cycles (on a simple viewpoint of the hardware)."
],
"score": [
31,
7
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
ib0bz5 | Why is it faster to copy things from a USB to my computer rather than from the computer to the USB? | Making backups and I noticed this happening, wondering what the difference is | Technology | explainlikeimfive | {
"a_id": [
"g1rtpn0"
],
"text": [
"On most mediums, write speed is slower than read speed. USB sticks tend to be slower than most hard drives, so that'll be the limiting factor."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ib12mu | My fan has an “ion” setting, what is it actually doing and how does it create ions? | Bonus points if there’s an ELI5 for benefits for ions. | Technology | explainlikeimfive | {
"a_id": [
"g1ry6bx"
],
"text": [
"What your fan is doing is using comparatively high voltage to ionize the air around it (strip off electrons from air molecules). The fan then sends those ions into the air nearby, where, so the claim goes, the ions attach to dust particles and other contaminants. These contaminants, now bearing an electric charge, are attracted to either collection plates inside the device or to the nearest walls or ceiling."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ib1gd4 | how does data recovery work from a hardisk | Like how isn't anything deleted permanently and how do softwares recover it | Technology | explainlikeimfive | {
"a_id": [
"g1s0eyr"
],
"text": [
"When data is deleted by the OS on mechanical hard drives, the hard drive isn't instructed to go to where the data is physically stored and overwrite it, instead it just goes to what is essentially a giant table of contents and deletes the entry there. From here, that space is treated as available, regardless of what actually is still there. Assuming that space hasn't been used for something else, it's still possible to instruct the drive to go to that physical location and read off whatever is written there, and if it looks like a file, copy it to somewhere else. Although the problem often becomes finding where that location is, which is why many recovery programs will start looking at all the space that isn't currently used and start piecing together anything that looks like a file"
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ib28wi | Do adjacent browser tabs know about each other? | Technology | explainlikeimfive | {
"a_id": [
"g1s5pg0",
"g1s5qnd"
],
"text": [
"Short answer, no. Long answer to not get deleted. There is no information that is sent between tabs. All your communications are addressed to the destination. Caveat: if you somehow got infected with some kind of packet sniffer or something through that less secure tab/website, it could read your communications.",
"This will depend on the browser, but in almost every case, no. The tabs are separate processes and don’t know about each other."
],
"score": [
16,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ib3tdf | Why is night vision footage always green? | Technology | explainlikeimfive | {
"a_id": [
"g1seu5x",
"g1sevu2",
"g1so5gv",
"g1slhun",
"g1snbow",
"g1toarp"
],
"text": [
"The human eye is most sensitive to differences in light wavelengths (colors) in the green band. By using green it is easiest to distinguish between the slightest variations.",
"The human eye distinguish different variations of the color green at the widest scale. By coloring night vision green it gives us the most clarity.",
"NVGs are mostly color now. The green tint is old tech related to the way the eye reads wavelengths of light and the chemistry we used to enhance low light conditions. We now keep that green tint in movies and TV as a convention to tell the audience it’s night time.",
"Night vision gear works like a black and white TV; they ignore the exact color coming from each particular spot and just display the total amount of light coming from that spot. The human eye is particularly good at picking out the whole range of different shades of the color green, so if green is the color which the display shows then the user is better able to pick out the very subtle changes in brightness in a dark environment",
"Night vision goggles used to be analog... URL_0 Image intensifier tube. Presumably it only intensifies so far... you get more bang for your buck if you’re using an output color that the human eye can distinguish feasibly at lower light levels.",
"Basically, it's not 'always' green. The incoming light gets turned into a black-and-white image. The phosphorus used in older generation night vision goggles (and some new of course) was then chosen because it turned the end-image green as mentioned because it makes it slightly easier to pick out more details You can also find white phosphorus nvg"
],
"score": [
29,
11,
7,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[
"https://en.m.wikipedia.org/wiki/Image_intensifier"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
ib58m2 | Why is Flash Player a dying/dead program, is it just obsolete? | Technology | explainlikeimfive | {
"a_id": [
"g1so5vt",
"g1spssj",
"g1sraf1"
],
"text": [
"Pretty much, yeah. When Flash came out, it got popular because there was nothing like it. But Flash is not very secure, even back then. Nowadays, there are simply more, better and safer alternatives, like HTML. EDIT: It's worth noting that this isn't a sudden kill on Flash. Websites have been slowly fasing out of Flash after being dependent on it for so many years. Like how in 2016 (IIRC), Google no longer supported Flash Player as a default feature on Chrome.",
"Flash allowed websites to display interactive, dynamic and colorful content (e.g. banners, interactive content, even games) at a time when websites were very non-interactive and more like static documents than applications. Many of Flash's features were added with little consideration of security (because security practices on the web were still being discovered/developed). As a result, a number of security holes exist in the flash application, which really can't be patched without breaking the content on a bunch of websites. Now with modern web features (html 5 etc) that can do everything that flash can, coupled with its security issues, flash is considered obselete and is being discontinued.",
"Lots of reasons, including: • Security. There are many vulnerabilities that can’t be easily fixed. • Performance (and battery life). The Flash player is inefficient on mobile and draws a lot of battery power. • Long load times. Flash .swf files are bloated and often have long loaders before rendering useful content. • Poor support for multiple screen sizes/resolutions. There is no easy/standardized way to make content “respond” to the size of the screen. • Accessibility. Keyboard users and screen readers will likely have a bad time with embedded flash, since there are no accessibility standards. • Development costs. It requires a source file and proprietary software to compile a new .swf file. It’s also difficult to communicate with other elements on the page compared to other web technologies. Development time is a lot longer (and therefore more expensive). • Proprietary. Flash is owned by Adobe and is not open source. This makes it difficult and sometimes expensive to support. Most modern web standards are open sourced, so the community can drive them forward. The alternatives (HTML5, canvas, wasm) are just downright better now."
],
"score": [
35,
29,
18
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ib8qzr | How do self-healing cutting mats work? | Are they like some special high viscosity plastic or something? Also, are there any microscope video of these mats healing? | Technology | explainlikeimfive | {
"a_id": [
"g1tkrvq"
],
"text": [
"From what I have read they are made of a bunch of tiny particles squished together and when you cut into it the blade goes between the particles and then back out instead of through. As if a hair brush were squished together into a solid form and the bristles were creating an appearingly solid surface."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ib9tj5 | How come the sense of sight and sound can be transmitted through technology while the other senses are not able to? | Hello! I just noticed while using my laptop that sight and sound are converted into code, transferred to the internet, then it reaches me. How come the other senses, especially smell, can't be converted into code? | Technology | explainlikeimfive | {
"a_id": [
"g1tewwl",
"g1teorq",
"g1tfjar",
"g1tqt3f"
],
"text": [
"Not the expert so I’ll let some one else answer but if I’m not mistaken sounds and light(responsible for vision and colors) travel by invisible waves which we can detect replicate and broadcast, but smell are just particles that are floating in the air, so to replicate it you would need to be able to detect and identify every smell you want to share and replicate it so it can be dispersed through the air, which we are current not able to do (both I think) again not an expert answer just tried to think logically until someone more capable can answer with better simplification and knowledge 🙏",
"It is more the lack of a delivery system. There are a couple of rare games that actually included a device to generate a smell. I will see if I can find a YouTube vid for you.",
"Smell/Taste - Ants Touch - Secret Hand Shake/Morse Code We can transfer a lot of information by encoding and decoding or by analogue transduction e.g. vocal cords - > air molecules - > eardrum - > cochlea - > auditory nerve - > brain. The latter is easy for human brains to read, and suits our timescales. Some animals sense their world through scents which move much more slowly but which carry large amounts of information bound up in their chemistries. Their brains are still determining their situation in the external world in whatever way they can. We can now encode information into DNA chemistry (too slow) or onto magnetic media (too fast), but not at a rate which our brains can use to survive in the niche we evolved into. However, a primitive version of what you suggest exists in the 4D cinemas where they spray perfumes and shake your seat in concert with what's going on up on the screen. As u/Mussie76 points out though, the signals to the seats are delivered through wires and somebody has to bring canisters of chemicals to the gas dispensers.",
"The only thing that makes sight and sound different from our other senses are that they are conveyed by changes in different forms of energy (electromagnetic and kinetic respectively) travelling through existing mediums (space and air respectively). So we can emulate those phenomena by manipulating that energy. Smell, taste and touch have a physical and/or chemical aspect that is much harder, if not impossible to emulate by manipulating energy. Or as another answer put it, it's the lack of a delivery mechanism that is the problem. Without some kind of Star Trek \"Replicator\" technology (which was based on Transporter technology and a lot of Sci-Fi hand-waiving) to create the physical particles for us to smell and taste, the next best thing is probably some kind of device to stimulate our senses directly, which we will need to physically attach to us and is an impractical commercial nightmare. Determining the composition of particles is another problem, we can do it now to an extent, but with [complicated machines]( URL_1 ) requiring trained operators, so that technology would need to improve before the particle equivalent of a camera or microphone are commercially viable. Touch might be relatively easier, we already have [electronic Braille displays]( URL_0 ), I imagine a \"touch display\" would just be an advancement on something like that. The camera equivalent would probably be some kind of super advanced 3D scanner that could determine texture, elasticity and other properties that contribute to touch. To be clear, it's not necessarily that we can't represent those base senses using code and data; if we can build the machines to measure it then we can find ways to represent it in computer code, and if we can build the hardware to emit it then we can develop the communication protocols to send it electronically. But again, sight and sound being energy makes them far easier to measure and represent with simple numbers."
],
"score": [
26,
7,
3,
3
],
"text_urls": [
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Refreshable_braille_display",
"https://en.wikipedia.org/wiki/Mass_spectrometry"
]
]
} | [
"url"
] | [
"url"
] |
ibb9fk | How can modern aircraft fly on just one engine if the other one fails? Shouldn't the torque produced by the functioning engine make the aircraft yaw? | Technology | explainlikeimfive | {
"a_id": [
"g1tueyn",
"g1u8lof",
"g1ujilb",
"g1v34qv",
"g1tum91"
],
"text": [
"Yes, the aircraft will naturally want to yaw due to the asymmetric thrust. However, this can be compensated for by the controls turning into the yaw to keep it going straight. There is a speed, called minimum control speed (Vmca), where there aerodynamic forces from the controls are not powerful enough to counteract the yaw if the aircraft is allowed to slow below this.",
"Most aircraft can mitigate this, but there were some instances where this exact thrust assymetry caused departure from controlled flight conditions - F14 A had a known issue at low speed / high yaw combo that could cause an unrecoverable situation, for example. But usually there must be a very specyfic situation / emergency for an aircraft not to be able to counter this. Especially commercial aircraft, literally designed around safety.",
"Yes but. The planes are designed to have enough counter torque available to even this out in safe flight conditions, and enough engine power in the remaining jet to keep flying. It is a bit like being in your spare tyre. You are no longer going on a cross country rally drive but instead you can drive like your grandmother to the nearest garage without fear.",
"Some light twins at their maximum weight are unable to maintain height on one engine. The live engine then takes you to the crash site.",
"The yaw can be prevented by the tail and rudder. Flying on one engine also creates unequal lift, counteracted by the ailerons then."
],
"score": [
213,
30,
17,
10,
8
],
"text_urls": [
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ibdmuv | Why do smartphone batteries discharge over time even if the phone is turned off? | I heard that leaving the accumulator empty for a long period of time is very bad for the capacity of the accumulator, so I charge my devices fully before turning them off. But I've noticed that when I turn them on again after one month they are almost always completely discharged. Could anyone please explain why this happens? | Technology | explainlikeimfive | {
"a_id": [
"g1uyscz",
"g1upzyn",
"g1uo7f4"
],
"text": [
"(Almost all) batteries will lose charge when not being used. As a rule of thumb, the higher the energy density, the quicker this happens. In the end, this is a consequence of thermodynamics. You could say it's unnatural for energy to be accumulated. It would dissapiate. Sometimes, this would take ages (like when a stone sits on a slope, only moving a little when it rains, maybe), but in the case of batteries, it can happen fairly quickly. There are exceptions, but these aren't all that useful as cellphone batteries.",
"Smartphones use some power even when \"off\" to listen for power button presses, USB charging devices, keep track of time, etc.",
"The charge state is only estimated by your device, there is no precise way to measure it without using the battery. Lithium Ion batteries temporarily lose capacity when not in use, because the material crystalizes. Charging and discharging them a few times will restore it though."
],
"score": [
7,
6,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
ibg3oc | How an adblock block the ads? | Technology | explainlikeimfive | {
"a_id": [
"g1vb9qu",
"g1vbxk1"
],
"text": [
"All the ads come form pretty much the same handful of companies, so an adblock just needs to block access to those companies websites and that stops the ads from downloading, a blank box for the ads still remains, but since the code of the box is pretty recognizable, the adblock can remove that as well pretty easily",
"When your browser connects to a site, the site also tells it to connect to the advertisers (through banner ads or pop up ads or what have you). The ad blocking software has a list of known advertising services and looks for their names in the data (like links) that's being fed to your browser. If it sees content hosted by \"Advertiser1 dot com\", then it knows there's a 99.9% chance that it's an advertiser and blocks the ad content from loading. It isn't 100% full proof. Some streaming services require the advertising to load before you can stream the video, so if the ad is blocked the video might never load."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ibk3yr | How do computers calculate pi to a million digits if floating point numbers are limited to about 6 digits? | Technology | explainlikeimfive | {
"a_id": [
"g1w5mkd"
],
"text": [
"How many digits you get in a standard floating point number varies with the computer hardware, programming language, and some other things, so it can be bigger, but you're right that no current system natively supports floating point numbers with millions of digits. The answer is that they don't use conventional floating point numbers. There's lots of ways to handle very large numbers in computers but they all come down to creating a different data structure than a float. For example, a perfectly effective but inelegant way to do it would be a text string of digits, which is usually only limited by the amount of addressable memory. Most pi-generation algorithms also only spit out a finite number of digits at at time, they don't go straight from 0 to a million digits in one step, so you don't necessarily need to keep track of all the millions of digits at once."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ibk90t | How is my ISP able to "clear blocks" or magically pump more internet into my modem when I'm on the phone with tech support. What can/are they doing on the other side of the phone? | After having issues with internet outages and super slow speeds, my ISP tech support is able to do something that makes speed checks seem moderately acceptable, albeit temporary. | Technology | explainlikeimfive | {
"a_id": [
"g1w7246",
"g1w6hkh"
],
"text": [
"1). Never, ever use the speed test site that is run by your cable company. It will lie to you. 2). They probably just reset your modem. Shitty modems with shitty firmware run fine right after a reboot but eventually have issues with memory leaks and what not that make them run slow. If they’re giving you some long explanation that’s something other than “we reset your modem”, they’re blowing a serious amount of smoke up your ass. Unless you’re dealing with the actual network engineers, tech support can’t really do much other than reboot your modem or tell to reload its configuration file.",
"It doesn't matter much what connection speed you have - whether you are paying for the premium subscription or the basic one - barring any location issues with long distances or so, your speed is basically controlled (rate-limited) by software. So, if they make your connection faster, it's because they change a number in some control panel."
],
"score": [
21,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
ibl2n8 | How does internet data travel so quickly internationally? e.g. Discord, Skype, instant messaging | Technology | explainlikeimfive | {
"a_id": [
"g1wd0m9"
],
"text": [
"When you access a site overseas, you are almost certainly routing some of your traffic through the giant underwater fiber optic cables that connect the Internet between the oceans. For a significant portion of the journey of your data, it travels at the speed of light. This is why latency is so low nowadays. Give it a try yourself, and run a speedtest to a country overseas. In a local area, the \"ping\", or how long it takes for one packet to go from one place to another will be on the order of tens of milliseconds. Internationally, a good connection should give you 200-500."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ibmqis | How can mail in voting be secure when the mail can be intercepted and possibly destroyed? (I am all for mail in voting, I just don’t understand how it is secure) | Technology | explainlikeimfive | {
"a_id": [
"g1wsatp",
"g1wu36s",
"g1wsodi",
"g1x993k"
],
"text": [
"That is just as secure as paper ballets, which get handled by volunteers/lower rung staffers. Those can also easily get lost or destroyed, but we have trusted those for a long time. The argument isn’t that Mail In ball outs are impervious to tampering, but that they aren’t any more susceptible that traditional ones, and shouldn’t be discriminated against. Plus some would argue that the cordinatuon required to mess with enough of the physical ballots to throw an election would require so many people that someone somewhere would slip up/rat, and the scheme would get caught. While people argue that not many people really know how the digital voting machines work, and what kind of access the companies that made them have, and what they could possibly do.",
"This maybe slightly off-topic, but people are generally pretty horrible at dealing or estimating risk. We have massive security apparatuses to dea with threat of terrorism, but we have no problem driving down a highway, even though 40k people a year die in car accidents. We are fearful of violent crimes committed in dark alleys, but the vast majority of violent crime suspects and victims know each other (i.e. your spouse is more likely to murder you than a random stranger). Point being (as others have pointed out), we worry about the risk of voting by mail, but completely ignore the risk that we already incur when voting in person. Additionally, due to sheer numbers, messing with individual ballots is rarely a way to alter a results.",
"Mail in voting would be as secure as any other piece of mail sent through the USPS. This is largely due to laws in place that offer significant punishment(it is a federal crime to interfere/tamper parcels currently being held or transported by the postal service) for messing with the mail. Additionally, the USPS has taken steps over their existence to increase trust in their service and as such are the defacto secure parcel service. Now clearly, the current actions of the Trump Admin are bringing into question the sanctity of letters in the care of the post office but that trust can't be completely obliterated in a week.",
"The problem is less a matter of interception than it is corruption at the source. Many of the proposals with mail-in voting intend to send ballots to every registered voter. However, registration lists are notoriously inaccurate because there hasn't been much incentive to cull them. They contain bad addresses, include people who have moved away or died, etc. When the only verification you have is that the ballot is filled and mailed in, that means you're potentially introducing an enormous number of fraudulent votes you have no way to detect. You also have the problem that mail-in ballots don't enable us to control the sanctity of the ballot in the same fashion as in-person voting. You have people who 'help' others fill out their ballot, which compromises the independence and secrecy of the ballot. These problems don't tend to exist with conventional absentee balloting because the voter has to specifically request the ballot and there aren't (classically) enough such requests to make it worthwhile to pursue a 'Get Out the Vote' strategy that relies on implicit coercion of voters. However, these issues can potentially be addressed. The major complaint right now is that they *haven't* been addressed and won't be addressed for this election season."
],
"score": [
15,
6,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ibt08s | When you take a picture of a digital screen with a mobile device, and then slowly zoom in and out on the picture, why do the “scan lines” distort in crazy patterns? | Sorry I can’t post a video of this effect - my phone doesn’t have screen recording capabilities. Hopefully enough people have noticed this that someone can answer. Edit: [here’s the best video]( URL_0 ) I can get. It should show what I’m talking about pretty clearly | Technology | explainlikeimfive | {
"a_id": [
"g1y4fn7",
"g1yaqrt"
],
"text": [
"That's called moire named from a fabric that has similar patterns woven into the material. It's an optical effect that arises when two sets of lines or grids move across one another. In this case, the grids are the screen's pixels and your phone camera's light detecting cells (also arranged in a grid pattern). As you zoom in and out you make the grids near enough in size to interfere with the other, but when you zoom in and out the grids are different enough the pattern lessens. Clothing worn on TV is often selected to avoid creating moire patterns because they are often very distracting when the wearer moves.",
"This is called the moiré effect. It happens when you have grid-like patterns overlaid on top of one another. The reason it's so pronounced on phone screens and monitors is because those screens themselves represent images with a grid of pixels. [Here's the not ELI5 explanation]( URL_0 ), but it has pictures that help."
],
"score": [
8,
4
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/Moir%C3%A9_pattern"
]
]
} | [
"url"
] | [
"url"
] |
ibu7fr | Why do almost all consumer PCs aside from Macs come preloaded with Windows? | What made Windows the default and become ubiquitous and why didn’t more companies use their own OS/a different OS? How did Windows become essentially a monopoly on computers? It’s on everything from Dell to Acer to Lenovo, why did these companies choose to put Windows on their machines? | Technology | explainlikeimfive | {
"a_id": [
"g1y8k2i",
"g1y7vg6",
"g1yhk0n"
],
"text": [
"A long time ago they were all sorts of different operating systems that were tied to specific hardware. You could get a Commodore, an Atari, a Tandy, or an Apple. IBM suddenly decided to get in on the game too. But instead of creating everything fresh they pulled together whatever parts they could to make their system. They made a deal with Microsoft who created PC DOS for the IBM and could freely put on any of their own computers. other companies started putting computers together at work just like the IBM computer. They got similar parts and what they couldn't buy off the shelf they reverse engineered and created clones of. Microsoft so they're soft where to go in all these clones. There were other operating systems too, but none of them succeeded. Microsoft connection to IBM and their business practices basically starved every other competitor out of the market. If they had not rescued Apple then Microsoft would have been the only major player. During all this, Steve Jobs left apple and created the Next computer just based off of Unix a separate operating system. It was not successful as a business, but that is where Mac OS X comes from. The Unix operating system has a whole bunch of different variants and similar systems like Linux available that you can put on systems just like you can Microsoft operating system they grew out of the same hardware environment. These days you'll see ChromeOS and Android coming on computers.",
"Apple always made their own proprietary hardware, the os was the draw, they had a graphical user interface before Microsoft and continued to make it user friendly over the years vs windows. Coding programs for different os takes time and the market can only support so many different operating systems. The majority of the business world runs on windows while Apple was always seen as more creative. The Microsoft Office suite on Macs tended to lag behind the windows versions. Apple didn't license out their OS to anyone. So major companies basically had Windows. Only other choices were Linux based operating systems that didn't have alot going for them at the consumer level until Google's OS came along, but even then, it still has limited use/market appeal.",
"The first round of personal computers were kits that you mail-ordered and built yourself. Mostly you had to program them yourself at the machine level, but some people began creating and selling operating systems for them. The second round (what most people think of as the original personal computers) came pre-assembled and had a simple, and proprietary, specific to the hardware, operating system built-in in ROM chips. This was the era of the Commodore 64, Apple II, TRS-80, etc. Generally each computer had its own proprietary OS (often a BASIC interpreter) and you didn't need another OS. But there were still other OSes sold - they were expensive however. Then IBM came along with its PC idea and needed an OS. Microsoft bought up the rights to QDOS (Quick and Dirty Operating System) for $50,000. That was a cheap hack imitation of an OS called CP/M, but targeted at the IBM hardware. Microsoft sold IBM on the idea. So initially, you had your choice of operating systems, but you had to pay for them in addition to the computer. 96.3% of PCs were ordered with the US$40 PC DOS compared to only 3.4% with the US$240 CP/M-86. People just didn't want to spend $200 more on an already expensive computer. Note: that's $628.89 in inflation-adjusted money. Would you want to pay over $600 more just for a different OS, when you don't even know the difference between the two? So naturally all software written for the PC was written for DOS, because that's what everyone was using. Therefore, when PC-compatible clones came out, they also included DOS so that all the existing software would be compatible too. You couldn't very well sell a computer and claim to be PC-compatible if no PC software would run on it! Windows was built on top of DOS, and just followed in DOS's footsteps as the standard PC-compatible OS. You can get PCs with Linux on it, and you can install other OSes instead, but Windows is still the standard that most all the hardware drivers and software are written for, so it sticks around. Few people use other OSes, so little software is made for them, so few people use other OSes because little software works with them (it's self-reinforcing). Linux has made a mark on the desktop, but it's still small and took a very long time to get this far. However, Linux dominates in the server market, and runs almost every supercomputer. The software they run is different and not dependent on the mass market."
],
"score": [
12,
4,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
ibwamb | How does an electric meter know how much electricity is being consumed? | My understanding is that when you plug something in and turn it on, it completes a circuit, and let's say if it's a 600W appliance in the US, you'd get 120V 5A flowing through the hot wire into the appliance and then the same 120V 5A will flow back through the neutral wire, through the circuit breaker and back to the grid (and if the circuit breaker detects a current imbalance it would trip, correct?). So what exactly is being consumed, you have the same amount of power flowing in and out of the appliance. And how does the meter know about it? | Technology | explainlikeimfive | {
"a_id": [
"g1ykld2"
],
"text": [
"> you have the same amount of power flowing in and out of the appliance. You have the same amount of water flowing from the bottom of a hydroelectric dam, but is the energy state of that water the same as at the top? What flows back on the neutral is 5A - at close (but not equal) to 0V. Power meters can measure current in two ways: via measuring the voltage on a small, known resistor inserted into the circuit, or by using the fact that a wire carrying electric current will develop a magnetic field directly proportional to the current. Power measurement is just current integrated over time. > (and if the circuit breaker detects a current imbalance it would trip, correct?) That's a GFI device. A circuit breaker responds to too large current by said current heating a strip of metal that deforms to release a spring, or the current developing a magnetic field that yanks the spring release. Most breakers have both systems, magnetic for short huge current spikes and the thermal for sustained overcurrent of less dramatic proportions."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
iby5iv | Where does unused electricity "go"? | Let's say I have a 100W solar panel outputting 5A at 18V DC under ideal conditions. If I connect a 18W load to it, I draw 1A. What happens to the other 4A? Or if I don't connect anything to it, where does the 5A go? I know that nothing flows through wires unless a circuit is completed so the electricity isn't stuck in the wires somehow heating them up. So where does it go and how does it dissipate? Is there circuitry inside the solar panel that tells it not to produce electricity at all unless there's demand for it? And what about a power plant, is it all programmed to only produce when there's demand? What happens if it outproduces, where does it go? Does it just heat up the generator? | Technology | explainlikeimfive | {
"a_id": [
"g1yv3et",
"g1ytw79",
"g1ytv3u"
],
"text": [
"Amps are the equivalent of work that a circuit is capable of doing. It's doesn't necessarily do that work all the time. Your example system produces up to 5 amps. Think of it as Joe can having the ability to do up to 50 push-ups. If Joe only does 10 push-ups the other 40 don't go anywhere they were never produced. The same is true with amps. If Joe tries to do 51 push-ups he will collapse. If you try to put a 6amp load on your circuit the breaker/fuse will trip.",
"Charge will build up across the semiconductor junctions in the PV cells until the voltage is sufficient to stop any more electrons jumping across. At this point there will be no electricity being generated, energy from sunlight will be converted to heat instead, so your panel will get a bit warmer.",
"If your power supply can output 5A at 18V that doesn’t mean it always will, it will create a voltage of 18V, which just means that there are more electrons on the negative cable than in the positive, and only if you connect something, electricity will flow. The amount of electricity depends on the old you put on it, the electricity it doesn’t draw, doesn’t go anywhere, it just doesn’t pass and the power supply doesn’t output the full 100W. In the case you try and draw more than 5A, the supply will not be able to keep enough voltage because all the electrons go away too quickly, so the voltage will go down"
],
"score": [
10,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
ic5cgj | What makes copying files slower or faster? | When copying or moving files (in Windows for this example) it shows you the speed at which the transfer is currently happening. However this is very rarely a constant rate and can vary wildly from second to second. What factors are involved in affecting this speed? | Technology | explainlikeimfive | {
"a_id": [
"g20ar3k"
],
"text": [
"How your computer is being taxed by running other programs. Your computer can only handle so many tasks at once, so when you have multiple programs running it sometimes has to juggle all those tasks, causing slow downs in your copying. It also has to do with file size, if you’re copying a bunch of photos for example, ones that have smaller files sizes will copy quicker than those that are larger, but if you’re just looking at a “photo X out of 100” progress bar it just seems like some are randomly causing slowdowns."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ic79qy | Why does Terminal show a "%" sign now instead of a "$" sign? | Technology | explainlikeimfive | {
"a_id": [
"g20ozoh",
"g22eu3t"
],
"text": [
"If you’re talking on MacOS, the default shell was changed from bash to zsh. The default prompt for zsh is %. Bash is $.",
"That symbol is simply an indicator that your terminal is ready to accept a new command from you. Which symbol it is in general doesn't really matter. Whoever wrote the original code that powers your terminal (the \"shell\") was free to pick whatever they wanted. Some shells even let you change it as a configuration option. The most common shells, the Bourne shell and its derivatives (like Bash), are used in most Unix systems by default, and have `$` as their prompt, or `#` if you're running as an elevated user. MacOS used to use Bash as its default shell, but as of the Catalina update, it was switched to Zsh (another Bourne shell relative), which happens to use `%` as its prompt."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
icatam | What does ejecting a flash drive or SD card from a computer do, and what happens if you don't? | Technology | explainlikeimfive | {
"a_id": [
"g21cxy8",
"g21d9ey"
],
"text": [
"Ejecting unmounts the drive from the file system. It ensures that no program is writing/reading data on the drive, so when you remove it no program will have issues and no files on the drive will be half-written. If you remove it without ejecting odds are nothing will happen - most programs are smart enough to know this might happen and plan for it - but it is possible that files on the drive will become corrupted and unreadable.",
"Ejecting the drive is like putting the lid on the cookie jar before putting it away. Sometimes, you put it away and don't spill any cookies. Sometimes a bunch of cookies fall out and break on the ground and then you can't eat them. So always put the lid on just to be safe."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
icg48z | Why are AMD processors not, or less, vulnerable to Meltdown and Spectre? | All the answers at [this Stack Exchange post]( URL_0 ) are too abstruse and complex. Can someone please ELI5 by relying on, but variating, u/zoox101's [excellent analogy]( URL_1 )? | Technology | explainlikeimfive | {
"a_id": [
"g22k5ry"
],
"text": [
"AMD CPUs were just as vulnerable to Spectre as Intel CPUs were. AMD's initial denial was an attempt at damage control by their PR department. Once their legal department realized what the PR department said they retracted their claim. Meltdown is a specific vulnerability in Intel CPUs. To use a similar analogy: You ask a teacher to hold onto a book for you. An Intel teacher takes the book from you and says that she is putting it on her desk. Except she doesn't necessarily put your book on her desk - she walks back to her desk and checks to see if she has an identical book already there. If she does, then she secretly dumps your book in the trash. After she's done this she realizes that she doesn't know if you're allowed to even be in the classroom and, as it turns out, you're not allowed to be in the classroom at all. So she tells you to get out without giving you your book back. But the thing is that it takes her slightly longer to place your book on her desk than it does to throw your book out. So if she kicks you out of the classroom quickly then you know that she had an exact copy of your book on her desk to begin with. Conversely, if it takes her a bit to kick you out then you know that she didn't. The AMD teacher checks to see if you're allowed in the classroom before taking your book back to the desk. Intel chose to use its method because your teacher doesn't have to be holding onto your book while she checks to see if you're allowed in the classroom. That frees her hands up to be doing something else during that time. The AMD teacher, on the other hand, has to hold onto your book while she's checking to see if you're allowing in there. That means that the AMD teacher needs bigger hands (which is expensive) if she wants to continue to use her hands during that time."
],
"score": [
28
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
icjh4t | How is computer code written onto Rom chips? (Like those used in old school video games.) | Back in the 8bit and 16bit era of video games, all the systems used came cartridges that consisted of rom chips. I kind of understand magnetic storage and optical storage, but I don’t understand how rom chips store code. Is the code written first and then the chips manufactured specifically for the code? | Technology | explainlikeimfive | {
"a_id": [
"g230hua"
],
"text": [
"It depends on the type of ROM chip. Modern ROMs are often [EEPROM]( URL_1 ), which can be erased and programmed electronically using an [EEPROM programmer]( URL_2 ), or [EPROM]( URL_3 ) which are erased by exposure to light. In the 8/16 bit era, most console cartridges were [Mask ROMs]( URL_0 ), which used photolithography (etching the circuit using UV light) to be programmed by the manufacturer. Although mask ROMs are still used today for mass-manufacturing since they're cheaper."
],
"score": [
7
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Mask_ROM",
"https://en.wikipedia.org/wiki/EEPROM",
"https://i.ytimg.com/vi/9UwmfIiKhGo/hqdefault.jpg",
"https://en.wikipedia.org/wiki/EPROM"
]
]
} | [
"url"
] | [
"url"
] |
icjrf8 | Mentall Ilness early stages or am I being watched? | Technology | explainlikeimfive | {
"a_id": [
"g22z7q9",
"g22z96m"
],
"text": [
"That is not how cameras work. They don’t have speakers. If they were hidden, why would they draw your attention with sound. Please, go get help. Even going to the hidden camera explanation is a sign. It’s okay, the brain is just another organ. If it messes up, you need help to get it working again. Go get help now.",
"Hidden cameras don’t usually have speakers. So, you can’t hear what’s on the receiving end of a hidden camera. Make sure someone isn’t just listening to a radio in a nearby room. Then get checked by a doctor."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
icjvec | the thought process behind adding "last seen" to apps. Isn't it only really useful for crazy partners? | Technology | explainlikeimfive | {
"a_id": [
"g23041i",
"g236ylj"
],
"text": [
"True, but also to see if the user is still active on the app or not. and if they are active, when was it last time they were.. It is useful for a lot of scenarios, crazy partners will find their way eitherways",
"It's kinda useful to determine if an account is still active or not. You're don't want to contact an account that has been inactive for 3 months"
],
"score": [
14,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
icklrm | what does vram do and what happens when you increase it? | Technology | explainlikeimfive | {
"a_id": [
"g233qd6"
],
"text": [
"VRAM (RAM of your graphics card) mostly stores textures and various internal calculation stages. If you have more VRAM than the game (or the other task) needs, nothing will happen. If you have less, various issues may occur: say, if the graphics card is unable to store all required textures for the game scene, it will have to unload some of them and request the required ones from the disk which is slow. At best, some textures will be blurry if the game's engine accounts for that. At worst, the game will crash or not run at all."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
icl67i | How do 3D glasses work? | Also, are there different methods so that they can work on all types of screens? | Technology | explainlikeimfive | {
"a_id": [
"g236i11"
],
"text": [
"It all depends on the general perspective you see an object. While seeing an object the right side of your eye sees the object in one angle and the left side with some different angle to see the same image, if in case you want it in the practical terms just close one of your eyes and see any object and repeat it for the other eye, you will see both your eyes look at the same object in two different angles. Now after getting two different images, actual magic happens in your brain, the brain combines both these images and makes it one. This gives you a feel that the image has some depth in it. Seems perfect till here, But when coming to some cinemas or TV's how do they create the same 3-D effect when the image that is displayed on the screen is 2-D or linear? Simple, when they shoot some 3-D movie they shoot in 2 different angles where in one is intended for one eye and the other angle is intended for other eye. The glasses that you wear has some filters to differentiate which angle is for which eye and which is for the other. You are ultimately fooling your brain that you are seeing some depth in the 2-D image, because each of your eye is seeing it in different angle. There are many glasses intended for watching the 3-D movie, the most popular ones among them are: Anaglyph glasses: This glass has two filers one with the blue filter and the other with red, while filming you shoot the same movie in two different colors i.e. one in the red and the other in blue and finally mix them when projecting it in the screen. While watching, your left glass will only allow the specific color to pass and your right does the same. So ultimately its like you are watching two different things. But the drawback with this glass is that its overall 3-D effect is blurred. 2. Polarized glasses: This is the most cheap and efficient glass, it has some filters in both the glasses. ( Note: little physics involved) The main principle in these glasses is polarization, since we know light travels as a wave(also as a particle). It has two fields magnetic and electric, but here for this, lets consider the main factor that is the electric field. When the light is moving in certain direction its electric field will be present in perpendicular to the motion of the wave, if the electrical field is perpendicular to the ground it is said to be vertically polarized and if the field is in the horizontal to the ground it becomes horizontally polarized. In one glass there is a filter which will only pass vertically polarized image and in the other glass will only pass the horizontally polarized ones. so we are ultimately back to the same principle where in both eyes receive different images. Circular polarization will fetch the best results in viewing an 3-D image/movie, the principle is all the same with one form being clock wise and the other anti-clock wise. In the glasses the circular polarization will be converted back to the linear polarization and will be reflected to our eyes. Hope this helped."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
icmm3y | why do electronics that are slightly malfunctioning work after we hit them? (E.g. remote controls, mice etc.) | Technology | explainlikeimfive | {
"a_id": [
"g23em43"
],
"text": [
"Usually it's some electric contact gone slightly loose, a piece of dust stuck between the contacting parts and other minor issues like that. When we hit the device, it shakes and things can get back to normal."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
icn8xm | How does a rectifier change AC to DC (and vice versa)? | I'm a guitarist with an interest in how my tube amps work. Some amps have solid state (SS) rectification, and some have tube rectification. Either way, I understand SS and tube rectification effectively does the same thing. My question is how it's able to do it at all. Thanks in advance! | Technology | explainlikeimfive | {
"a_id": [
"g23klvl",
"g23kn0z"
],
"text": [
"It starts with diodes Diodes only let current flow in one direction. AC flows in both directions and looks like a sine wave when you graph it out, where half the wave is above 0 volts, the other half is below. A half rectifier, really just a diode, will basically block the negative current, so only the positive gets thru. Graph that and you'd see the top half humps but a flat 0 where the negative valleys would be. In an ideal world that is, there is some leak current, but that's far more detail for this. Whenever the diode flattens out the negative current, it gets lost as heat, and the 120V you get out of the wall is reduced to about half (since half the usable current is gone). This wrecks havoc on components because they like a steady stream, and for an amp would induce a lot of noise. A full rectifier, which is four diodes arranged a specific pattern effectively saves that bottom half and makes it change directions. So what was a since wave is now a bumpy wave, but it's all positive voltage that DC components can use. However, they still prefer a steady stream. Other components, like capacitors, are added to smooth out this bump. It's never prefect, but it's far better.",
"A rectifier uses diodes, electronic elements (no matter tube-based or semiconductor-based or whatever) that only allow the current to flow through them in a single direction. If you apply the voltage to a diode in one direction, the current will flow, and if you flip the diode, the current will not flow. An AC constantly alternates between the positive and negative voltage. If you connect an AC cable to a diode, it will only allow the current through when the voltage is, let's say, positive. But it will still not be a good DC because instead of constant voltage, there will be peaks and pauses. If we add [a few extra diodes]( URL_0 ) (the diode is drawn as an arrow-like triangle with extra line, it only allows the current to flow in the direction of the arrow), we can \"catch\" the negative half of the oscillation as well, \"flip\" it and merge with the positive half producing the better DC. It will still be oscillating but the current will always have the same direction and most devices will work, and if needed, we can try and smooth it a bit. & #x200B; An addition about \"vice versa\". Power inverters, things that convert DC to AC, feature some kind of a power switch (be it a physical switch or a transistor) that inverts the voltage when powered, then becomes unpowered after the voltage has been inverted, flips back, becomes powered again, inverts the voltage again and so on. This turns a constant voltage into an alternating one, though the shape of the wave is different which can cause trouble if you connect a cheap inverter to a sensitive device."
],
"score": [
8,
4
],
"text_urls": [
[],
[
"https://www.electronics-tutorials.ws/wp-content/uploads/2013/08/diode20.gif"
]
]
} | [
"url"
] | [
"url"
] |
icrhe4 | what are machine learning algorithms ? Such as keras, tensorflow etc. ? Are they software ? Or some codes ? | Technology | explainlikeimfive | {
"a_id": [
"g24disf"
],
"text": [
"An algorithm is a series of steps to perform some calculation. Those can be written in words, eg: \"to find the arithmetic mean of a series of numbers, add them all together and divide by the amount of numbers\". If you want a computer to perform that, you need to write a program that executes those steps, and then you have a piece of software. But an algorithm could also be performed purely in hardware, eg, here's a [mechanical adder]( URL_0 ) that uses nothing but wood and marbles to add numbers. Keras and Tensorflow aren't really algorithms though, they're libraries, which are large collections of code that perform many different algorithms. An algorithm is more like a cog, and a library is more like a machine built from those cogs."
],
"score": [
10
],
"text_urls": [
[
"https://www.youtube.com/watch?v=GcDshWmhF4A"
]
]
} | [
"url"
] | [
"url"
] |
|
ics0ep | Why did old game cartridges need batteries to keep data? | As far as I know, modern hard drives, SSDs, and optical medias don’t need power to keep data on them. Why did old cartridges need to? In addition, if the cartridge lost power, why was only player progress lost? If data was lost, wouldn’t the whole cartridge be lost? Why was only the player progress lost, and not the actual game? | Technology | explainlikeimfive | {
"a_id": [
"g24fee1",
"g24feq1"
],
"text": [
"The battery wasn't required to store the ROM data (ie the game itself), it was only needed to store player data. The manner in which these two things were stored was different, because the game data was written once, in a factory, where as the player data was written repeatedly by the console itself, and thus it used different methods to store the data. In a technical sense, this storage was actually RAM and, as such, required constant (albeit minute amounts of) power to maintain the data.",
"Old cartridges predate the invention of flash memory and optical media. All we had at the time for re-writable memory was magnetic storage (hard drive, floppy disk) and actively powered memory (RAM). Magnetic storage was way too expensive/complex to put in a cartridge, so they basically had a tiny RAM chip that stored the player data and a battery to keep it alive. The game program was in read-only memory (ROM). This doesn't need power to maintain itself so it works just fine if the battery dies, but you can't change it once it's made so it's useless for stuff that needs updating, like player data. There was is specialized type of ROM that you could erase and reprogram with special equipment, called an EPROM, that could theoretically have worked for storing player data but nobody wanted to put the erase/write equipment in a cartridge. It's rough analog today is an FPGA. If you ever see photos of older chips with a \"window\" where you see the actual silicon inside, that's an EPROM. The window is there to allow the erase to happen (you shine UV light on it)."
],
"score": [
5,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
ict3zo | What makes reproduction video game cartridges so bad? | Technology | explainlikeimfive | {
"a_id": [
"g24p4ak"
],
"text": [
"People who collect vintage games (like myself) want authentic products. If you just want to play the game, you can usually do so through other means- emulation, virtual console, everdrive, etc. The point of collecting physical copies is to have authentic versions. No museum wants to display a photocopy of the mona lisa. I have one repro cart of a snes game that was never released in the US. This allows me to play it on my snes. I knew it was a repro cart when i bought it, and i was fine with that. Other repros can be good too. For example, if you want to play metal slug 1 on your neo geo aes, you can shell out $15,000 for an original cart, or pay about $350 for a repro that looks nearly identical and uses the authentic chips from an mvs (arcade) cart. The problem comes in when people try to pass off repros as authentic copies of high-value games. That is fraud. For a buyer though, you arent going to get in legal trouble if you buy a repro. As long as you arent getting ripped off, if a repro allows you to play a game that you otherwise wouldnt be able to, there is nothing wrong with it."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
icu5ly | How are 24 different satellites keeping track of around 4.5 billion people's technology? (That number being the ammount of the world that has access to the internet). | Technology | explainlikeimfive | {
"a_id": [
"g24su0g"
],
"text": [
"They're not. What 24 satellites are you talking about? GPS? That's a one-way technology. The satellites broadcast information but don't receive anything from the devices using the signals."
],
"score": [
16
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
icuxcc | Why programs just sometimes don't open | Technology | explainlikeimfive | {
"a_id": [
"g24yv86"
],
"text": [
"Think of your computer's hardware like a city highway system, there's data in the form of electricity (cars) going every which way. The routes are the same but the cars will be in different places on the road, parking lots will be full or empty,etc...etc...etc... This is true even while you're not actively using any applications, because the OS itself is performing a variety of ongoing functions and many applications will be running things in the background even if there's nothing showing on the display. Executing a command is a bit like driving somewhere, you've got to get the data from A to B. SO, imagine you tried to treat your morning commute with the exact same input, as you're expecting the computer to do. One day you're going to pull up to a stop sign that already has a car sitting at it, if you don't apply the brake sooner (changing the input of the commute) you're going to smash into them. Same idea if you don't change the way you merge with the freeway, some days may be fine but other days you'll smash into a traffic jam or get flattened by a speeding truck unless you adjust the inputs every time to change that merge. Your computer is doing something like that, except it's playing as every driver all at the same time. Those routes aren't changing and the final destination (Safari) is the same but it has to carefully manage the queues and timing in transit to make that happen. Sometimes, even if you don't see it on screen, there's a background process doing something that causes a traffic jam. Sometimes there's just an error that causes a collision."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
icv1ov | Why is technology rapidly advanced in the past century? Why didn’t it happen before 1900? | Technology | explainlikeimfive | {
"a_id": [
"g250446",
"g250zym"
],
"text": [
"It did, honestly. The industrial revolution was a major major change. We may think that all the gadgets we have now are significant, but the massive change from agricultural to industrial-vmbased economies impacted EVERYTHING",
"There are countless other factors, but one of the largest factor in how and when technology has progressed is how much energy we have learned to use. In the 1800s, civilization began breaking into energy use on a scale that had not been possible before. Partly because resources had not yet been discovered, and partly because it takes time to go through the trial and error of developing technology - the industrial revolution was the period in which we finally broke into tapping the enormous amount of energy available in coal, and eventually fossils fuels. Coal and fossil fuel broke us out of using livestock, water (mills) and manual labor to produce energy. With coal and petroleum and other high energy resources, we could power machines, factories, and transport goods at such a rate and scale, that our industry quickly developed the capacity to accelerate its own growth. By 1900 you have goods being transported by locomotive, powered machinery in the mines and factories, and technology generally doing labor on a scale it never could. Having established this baseline of power, it became possible to use that power to create even more powerful equipment and further use available energy to do even more complex work! The distance between a horse drawn cart and a locomotive is a lot greater than the distance between a locomotive and a bullet train. Those huge hurdles were crossed and growth multiplied itself. It all comes back to how much energy you can harness."
],
"score": [
18,
7
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
icvpos | How barcodes work? | Please as simply as possible 🙏 | Technology | explainlikeimfive | {
"a_id": [
"g254nsr",
"g254cv5"
],
"text": [
"To add to the previous answer - the scanner reads each line as either a one or a zero and then this results in a unique number attached to the product being scanned. UPC codes were one of IBMs big inventions!",
"It reads them and each stripe represents a number, this will normally be matchable against a database. For a vendor to sell a product, they set it up and add number and price to start in the system so when scanned it shows as correct product and price at point of sale."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
icxjob | When a plane takes off and the nose lifts up why does the tail not hit the ground? | 27 years old and flied on numerous planes and this has always bothered me. Even had it explained by family before and I still don't get it. I.e. If I lift my hand up my fingers go in the air but my palm would hit the table... Why do the tails of planes not hit the ground?!? | Technology | explainlikeimfive | {
"a_id": [
"g25ex74",
"g25fzsc"
],
"text": [
"They don't hit the ground because the pilots are not pulling all the way up. If they did then it'd hit the ground. Pilots usually go through hours and hours of training. When it does happen, it's called a tailstrike. URL_0 URL_1",
"The back of the plane tapers up to accomodate that angle... look at this [side profile of a 737]( URL_0 ). And don't forget the landing gear wheels give the plane further clearance from teh ground. The plane only tilts further up once it's left the runway."
],
"score": [
11,
4
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Tailstrike",
"https://www.youtube.com/watch?v=4XgFQhxsdLY"
],
[
"https://uploads-ssl.webflow.com/5ecbef0c7557e7ba0f693039/5eebf6d65b67afa52d2715cd_90c99dab9eb50fe46757a6a7aa87d7984c1cbbbc_boeing-737-max.jpeg"
]
]
} | [
"url"
] | [
"url"
] |
icxryl | How did "cheat" cartridges like Game Genie work and find cheats and hidden options in games? | Technology | explainlikeimfive | {
"a_id": [
"g25htyr"
],
"text": [
"Such cheat cartridges modified parameters in memory. The modern equivalent of this would be like Cheatengine for PC. As an example, let's say you're playing a beat 'em up and want infinite lives. While you're playing the game, the game needs to know how many lives you currently have. This is stored in memory (in hexidicimal, which is base 16 - essentially 0-9, and A-F as digits instead of just 0-9). 00 would be zero lives, 02 as 2 lives, 0A as 11 lives, etc etc etc. The game genie modifies the value to be for example, FF - 255 lives."
],
"score": [
35
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
icychw | How come phones often shutdown before the phone battery is truly dead? | Technology | explainlikeimfive | {
"a_id": [
"g25k0m6"
],
"text": [
"It's bad for the battery to be truly dead. Some lithium chemistries can't be recharged at all from that state. The phone software is trying to prevent that sort of \"bricked\" state, by shutting off to conserve charge. Just charge your phone, and you won't have the problem."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
id3tzy | How secure are these password management programs really? | Technology | explainlikeimfive | {
"a_id": [
"g26m94a",
"g26p1n1",
"g26m3bg",
"g26n0mh"
],
"text": [
"With respect to security, a password manager is akin to a safe. Given enough time, someone could break into it and access all your passwords much in the same way someone could theoretically crack your safe and steal the deed to your house or all your jewels - although there are some ways to mitigate this risk like using a password manager that stores passwords locally, or keeping the program on a thumb-drive and not on a cloud service, etc. I can't speak to the type of encryptions used (perhaps someone could supplement this answer if needed), but in general these programs are trusted by the community and I think the good ones are open source which means the community can look at the code and verify there aren't any backdoors into the program. The key advantage to using a password manager is that you can lock all your passwords behind one very complicated password. First off one very long and complicated password is extremely difficult to crack, and as long as you aren't writing down that password on your computer/phone/paper, it is highly unlikely that someone will ever guess it. Second, because all you need to do is remember one very long and complicated password, you can now make all the passwords in there complete gibberish that would be impossible to remember or guess. In doing this, there's virtually no reason to have repeating or similar passwords. That in itself adds an extra layer of security to your various accounts. Another thing you can do it you're really paranoid is have another string of text that you append to those saved passwords that only you know (i.e. remember, not written down). That way if someone did gain access to your saved passwords they still wouldn't be useful without knowing that additional string of text that needs to be appended to the start/middle/end of every password. Also, obligatory [XKCD]( URL_0 ) Edit: changed for clarity.",
"In practice, most people use the same password for many sites. Thus, if one of the many sites has a leak, attackers can try to use the same password for many other sites. One way to alleviate this is to use completely separate passwords for every site, but that's hard and most people give up or don't bother, or they store the passwords insecurely. That's where the password manager comes in. Effectively, it reduces the attack space of \"every site for which you have ever made a user\" to \"a single site which hopefully has better security practices\".",
"It's most secure to have all your keys in a safe than open all the doors whit one key. The truth is that you cant generate randoms strings, and once one of your passwords it's compromised all are. This programs use nearly true random generators, and many times use two factors authentication, this means that not only you have to have the master password also you have to corroborate all access in real time, this means you are in charge of all access.",
"Many have been independently audited to confirm that, as a piece of software, they are legit and as trustworthy as the science and math allows. If you're shopping around this might be something to check out. These programs solve the issue of \"all my passwords have a theme\" by allowing you to use truly random passwords instead. In fact usually these programs will generate passwords for you so you don't have to. This makes all the individual sites you visit (eg: reddit) as safe as possible. Even if your password leaks from these web sites your password isn't re-used anywhere nor is any \"theme\" given away. This is the goal because hackers will usually get email addresses + passwords from site A, then try to login with them to site B. This is what you want to protect yourself against. That and forgetting passwords or just the hassle of typing them. The password manager itself, however, is an all-eggs-in-one-basket scenario, but the real risk is your password for this site. Of all the passwords you have this one must be remembered by you and must be good. If the website has a data leak your password is the only thing preventing the bad guys from getting *all* your other passwords. In the event the web site somehow dies and your password collection was wiped out you would have the option of asking other web sites (eg: reddit) that you forgot your password and to send you an email to reset it. To make password guessing harder for the bad guys schemes like pbkdf2 are used to encrypt the data with your password. The main highlight of this scheme is that you can give it an \"effort to decrypt\" number which slows the process down as the number gets large. The idea is that making a single password guess takes a lot of CPU power, which although it's still a fraction of a second it means you can't guess millions of passwords per second. Again this is a defence that requires your password be good, and using a password of \"123456\" means they don't need millions of guesses, they hardly need hundreds. Aside: this also means that there is no password recovery or it's a weird process. Anything that would allow your password to be easily recovered in case you forget it would also be a means for the bad guys to break into your password account."
],
"score": [
55,
4,
3,
3
],
"text_urls": [
[
"https://xkcd.com/936/"
],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
id61ev | what’s the difference between and Intel 5,7 and 9 processor? What do those numbers actually mean | Technology | explainlikeimfive | {
"a_id": [
"g26z5b6",
"g26zja3",
"g27m8q2"
],
"text": [
"The numbers themselves don't mean anything. It's just marketing, really. Depending on what task you are trying to perform, ones with lower numbers can out-perform ones with higher numbers, but usually it's the other way around. & #x200B; There was a time when the different names meant at least \\*some\\* discernable characteristic - 3's and 5's weren't Hyperthreaded whereas 7's and 9's were - but it's even blurrier now. & #x200B; Your best bet if you're looking to buy one or put together a machine is to determine what you want to actually use the machine for, find benchmarks that are a decent representation of that, and forget about the names.",
"The numbers themselves don't mean anything. On Intel Core processors, they are just \"brand modifiers\" meant to give consumers an idea of which one is better (3 is lowest functioning, 9 is highest functioning). The actual differences are mostly cache size and speed. However, these may also differ with the generation of the processor (you could compare an older 8th gen i7 to a newer 10th gen i5).",
"There's no meaning besides a made up name about how good Intel wants you to think it is. Basically: Celeron=$ Pentium=$$ i3=$$$ i5=$$$$ i7=$$$$$ Intel probably justifies this saying it simplifies all the complicated attributes of CPUs into a simple to understand name. There's some truth to that but it also gives Intel the freedom to make it up however they find most advantageous, which can also be somewhat deceptive at times. Specifically, I suspect they made up these names around the time when mainstream buyers were starting to buy more laptops than desktops and Intel wanted to hide (or \"de-emphasize\") the fact that you get less performance in mobile processors than desktop equivalents. Otherwise they could easily have just used the number of cores/threads as the name, but they didn't want you to think about how you're getting half as many cores on a mobile i7 as on desktop. They want you to think it's worth spending $$$$$ because it's an \"i7\" which doesn't mean anything except that it costs $$$$$, circular logic that justifies itself.. What's really important on processors? Cores and threads mostly. Then probably the architecture/process which used to be encompassed in the generation number, but now Intel has abused that to be meaningless also, having rehashed the same architecture and process for 5 generations, half of all the generations since Intel starting using the Core i7 naming.."
],
"score": [
8,
6,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
id7p14 | Pay to play games | Technology | explainlikeimfive | {
"a_id": [
"g2775uh"
],
"text": [
"Either plain lies or a pyramid scheme where you need to invite friends in the game and get a bit of a reward when they start spending money on microtransactions."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ida3nh | What is a kernel? | Technology | explainlikeimfive | {
"a_id": [
"g27m2gw",
"g27lk4z",
"g27wnhl"
],
"text": [
"The kernel is the core of your operating system. What is an operating system you asked? Well it is a program designed to create an abstraction of your computer, for other programs to use. Basically computers are made from various part, with various tech made by various companies. An operating system is required to make all these diverse hardware the same, virtually, from the perspective of other programs running. You webbrowser don't need to know which type of video card do you have, it will just all functions from the operating system that will draw stuff on screen. Now, the kernel is the part of your operating system that manages the hardware. Let take the memory for Instance. You might have 8Gb of RAM, well its the kernel job to tell to each program how much they can use, but also to make sure that they are only accessing the memory allocated to them. whatever happens in your browser, it shouldn't be able to change a part of memory reserved for another program. The kernel makes sur of that. It will also manage the CPU, telling each prgramm when they will run and when they will hold, control the disks and IO of the system, its in the center and involved each time data come or go somewhere. Kernels are important because otherwise, any program could change anything on your computer. A Bios is simply a very tiny operating system that is launched at startup. it's role is to ensure all cards are working, and start the boot process: it will loop through all storage device in a specified order and launched the first operating system it can find.",
"A kernel is the backbone of your operating system. It's the part that handles the transfer between the physical parts of your computer and the purely digital parts, to some extent. The difference between open and closed has more to do with what can access and edit the kernel; a closed kernel can't be edited typically. BIOS is the basic input/output system that is apart of your computer. BIOS is the thing that boots up your computer and get it ready for use. The BIOS sets everything up so the operating system can get started with everything it handles. As the name implies, it's basic; it's pretty stripped down so that you can use a mouse and/or keyboard to access certain features of the computer without necessarily running an operating system.",
"Computer hardware can be all kinds of random shit. Different kinds of drives, different graphics hardware, different amounts of memory - and a vast and baffling array of chipsets that drive it all, each with different ways of handling stuff. Writing code that can universally talk to all this stuff (and work out what it's talking to) would be a gargantuan task. It would be huge, and it would suck - any time a manufacturer changed anything, all their customer's software would need to be re-written. It's a bit like the way cars have all kinds of different engines and differentials and gears and other car-stuff that I know nothing about - it would suck if you had to learn to drive one exact make and model of car, only to have everything you learned become useless the moment you try to drive another. But they get around that with a common interface. All cars have different innards, but they all have a steering wheel, brake, accelerator and gearshift (and sometimes clutch). The indicator lever is almost always where you expect it to be, as is the headlight lever. There's a standard layout, and the controls always do standard things, so you can just get in and drive. Inbetween those standard controls and the model-specific hardware, there's a layer of wiring and mechanics that hooks them together, so the driver doesn't have to think about the changes, and the engineers can design the most powerful and efficient engine and stuff, and it translates between the two. That in-between layer, in a computer, is the BIOS - the Basic Input/Output System. It's a layer of on-chip software that knows about all the custom hardware shit on the motherboard, and how to drive it. And it presents a standard, known set of controls to the actual software on disk, so it can actually do stuff with your computer like load up Windows off the disk, and show stuff on the screen. Now, your operating system is kind of like that, on a much bigger scale. It gives individual applications a standard menu of controls - like showing text on screen, reading a file from disk, sending stuff over the network, etc - so everyone can write their programs the same way, and it handles the specifics for your particular computer and the way it's set up. Operating systems as a whole are a huge bloated pile of programs and drivers and utilities and subsystems and general random crap. They're the whole car, basically - the seat controls and the cup holders and the seat warmers and the powered headrests and all the rest. But right down at the core of them is the *kernel* - a fairly minimal standard interface that provides the most basic services for an application to consume. Just the basics: talk to files, talk to the network, talk to the screen. Reserve memory, Load programs, switch programs, close programs, release memory. Your pedals and your steering wheel. Linux has an 'open source' kernel, which means anyone can read (and potentially even contribute to) the human-understandable code that the kernel is built from - and so find bugs and vulnerabilities quickly through millions of people scrutinizing it. Macs and Windows have closed-source ones - mystery meat, with a lot more effort spent hiding the contents from people so they can't craft exploits or do things that apple and microsoft don't want you doing with it - security through obscurity, as it's known. Neither is necessarily better - unless you're doing hardcore developmenty stuff, none of this matters to you. Just get the one with the comfiest seats."
],
"score": [
19,
8,
6
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idbmk3 | Why are phone screen still made in breakable glass? | I broke mine yesterday and it occured to me that phone could be made of plexiglass or unbreakable glass or any other material than the weak material currently in use. Why is that? | Technology | explainlikeimfive | {
"a_id": [
"g27vbae",
"g27w0ot",
"g27ux0u",
"g27y6vw",
"g27xnsy",
"g283qoj",
"g27vjqr",
"g27w1wd"
],
"text": [
"Plexiglass isn't a glass, it's plastic: it scratches really easily. And there is no \"unbreakable glass\" so I'm not really sure what you're referring to. If you mean like the one in car windshields, that one still breaks but the fragments are kept in place by thin layers of plastic laminated together with the glass: you still see the cracks. Phone screens are made of glass whose surface has been strongly hardened to increase scratch and impact resistance, but like any brittle materials they still break in some cases.",
"1. plexiglass scratches. It scratches *really bad*. Instead of cracks, you'd get a buildup of uneven surface and scracthes over time. 2. unbreakable glass - yeah, let me fetch some of that. I think I left it behind the crate of weightless metal. Corning Gorilla Glass is *stupidly strong*. Unless you hit it on the very edge, it can survive a weak hit from a hammer. More like stop buying cheap phones with cheap screen glass composition and put a thin rubber case of it to protect the weaker edges. For extra points put on a screen protector which absorbs some of the energy from a hit and shatters before the actual glass.",
"Glass is brittle but its surface is really hard and so it’s more scratch resistant than almost anything.",
"So basically there are two battling qualities - resistance to scratching and resistance to cracking. The softer the material is the less likely it's to crack, but more likely to scratch. The harder/more brittle the material is, the harder it is to scratch, but easier to crack. PS. In most cases you can fix this, by adding a bazel made out of the soft material around the phone. But most people prefer their expensive phones bazelless and without thick rubber cases. So they get cracked screens :)",
"In a better world, all phones would have a replaceable, factory installed screen protector. It would add pennies to the cost of a phone. And if/when it breaks, the owner can easily replace it. But then, your retailer wouldn't be able to sell you an aftermarket screen protector for $20.",
"They used to use plastic screens before capacitive touch screens were the thing. They used pressure touch screens. And those screens would get scratched and cloudy in no time at all and looked like shit.",
"Like u/chompateef said, it's because glass is more scratch resistant than other \"unbreakable\" materials. Scratches on your screen can make it blurry and eventually you won't be able to see anything if enough scratches build up, so it's important for the screen to be scratch resistant.",
"There are a small number of ruggedised phones available with screens that won't break as easily as glass phones. The Motorola Moto X and Z had a variant named \"force\" that had this feature. The screen was made of more layers laminated together and had a plastic top layer. One downside was the \"finger feel\". Glass is very smooth and fingers slide over it better than the plastic \"force\" screen. Another option is to apply your own screen protector. In a drop, this tends to shatter whilst the phone remains OK. So it's a sacrificial layer that can be easily replaced when damaged. Some phone come with a screen protector already fitted."
],
"score": [
64,
56,
19,
12,
5,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
idcc40 | Why do all media buttons look the same | Technology | explainlikeimfive | {
"a_id": [
"g280d70"
],
"text": [
"They are all based on the standard controls from the old magnetic tape players. Triangle indicated that the tape would move in that direction at normal speed: Play Double triangle would indicate the tape would move in that direction at double speed: Fast Forward Double triangle reversed would indicate the tape would move in the opposite direction at double speed: Rewind Square would mean that the reels would stop moving entirely: Stop As newer devices were invented - like CD players - they used the same buttons because people were already familiar with the functions. Even though the functions use totally different mechanisms to perform, people understand what the button symbols mean so there is no reason to change them. There are quite a few anachronistic things like this in society that we use just because we understand the meaning, even though the current function is divorced from that meaning. Case in point - hanging up the phone. No one actually 'hangs up' the handset to end the call anymore, but we understand that 'hang up' means to end the call, so we keep using that phrase."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
idcgei | how do people build those oil rigs on deep seas/ocean and how do they know that there is oil there? | Technology | explainlikeimfive | {
"a_id": [
"g28242z",
"g281g20",
"g282br4"
],
"text": [
"I’m not sure about the engineering and construction of offshore oil rigs, so I’ll answer the other part of your question. How oil and gas is searched for and found is known as the exploration side of the industry, and is the most costly aspect for oil and gas companies. The Wikipedia page for [hydrocarbon exploration]( URL_1 ) is pretty good and probably has all you need, but I'll try and give a quick overview here. **Step One: General Geophysical Exploration** This involves carrying out geophysical surveys, which might involve collecting magnetic, gravity, or seismic data about the seafloor from a ship as it passes above. Typically a combination of these are used, though [seismic imaging surveys are the most widely used method]( URL_4 ) What is being looked for is any indication in the sedimentary layers of the seafloor that certain structures are present which are known to form 'traps' in which oil can collect. To explain this, there are several steps necessary for an oil deposit to be just sitting there waiting for extraction. As well as the actual organic matter causing its initial formation, any oil made will subsequently migrate out from the source rock. Surveys are searching for potential host rocks (the oil migrated from source rock to a host rock) which are overlain by an impermeable layer, trapping the oil in the host rock, rather than have it leak out onto the sea floor or just disperse throughout rocks over a great area, resulting in a hydrocarbon concentration too low to be extracted. Some of the main traps for oil are illustrated [here]( URL_3 ) **Step Two: Focused Geophysical Exploration** If such a structural trap is thought to be possible, further seismic surveys will be done in more detail, bouncing sound waves from the ship (or an instrument towed by the ship) onto the seafloor and seeing what comes back. This builds up a better picture of the subsurface than the general exploration done prior. It may look something like [this]( URL_2 ), or it is probably where the 3D approaches are used. **Step Three: Exploration Well** If it's looking promising after the detailed seismic surveys, an exploration well is drilled, which is a borehole smaller than a proper extraction well, with the sole intent of gathering more information directly from the layers of interest. A heavy mud is used as a drilling lubricant and to maintain the confining pressure in the borehole. During drilling, chips of rock, usually less than about 1/8 inch (6 mm) across, are cut from the bottom of the hole by the bit. Mud, jetting out of holes in the bit under high pressure, washes the cuttings away and up the hole. A lab will be setup next to the top of the well where cuttings can be analysed. This is the job of the wellsite geologist, or 'mudloggers' as they are commonly known. Analysis is typically done by examining the cuttings under a microscope, but may also include looking for fluorescence under a UV light. Mudlogging may be combined with wellsite logging, which involves lowering a 'logging tool' (or a string of one or more instruments) on the end of a wireline into an oil well (or borehole) and recording petrophysical properties using a variety of sensors. Logging tools developed over the years measure the natural gamma ray, electrical, acoustic, stimulated radioactive responses, electromagnetic, nuclear magnetic resonance, pressure and other properties of the rocks and their contained fluids. **Step Four: Extraction Well** If everything in step three indicates there is enough oil in the rocks to make for profitable extraction, then the company will go ahead and drill a larger well in order to get that good stuff. One interesting aspect of extraction is 'geosteering'. A geosteer is in charge of adjusting the borehole position in realtime as it drills down, in order to reach the target(s). All of the methods mentioned so far are utilised in order for a geosteer to make decisions about how to change the borehole angles to keep drilling in the right direction. Because geosteering involves synthesising lots of information about the well as it is being drilled, specialist software is used to inform the process, which looks something like [this.]( URL_0 )",
"Build: You build them in a shipyard and then tow them out to the sea. Then you anchor them down. Deep sea oil rigs are basically ships optimized to stay still. How you know oil is there: Various methods, including measuring gravity, seismic analysis, rock sampling (the presence of a certain type of rock can hint at oil nearby), and finally just drilling down and looking.",
"Those are two separate questions, so let's tackle them one at a time. They don't \\*know\\* the oil is there until they actually drill a well and check. The first step is to have some geologists look at geology and make educated guesses about places that may have the right geological history to both produce and trap oil. Then you send a seismic survey vessel out to do a survey. It tows a big array of hydrophones (underwater microphones) behind it and shoots a very powerful air cannon to make booms in the water. The hydrophones listen for the return echos and uses that to build up a \"picture\" of what's below the seabed. It's basically really complicated sonar. It can't actually see oil but it can see layers of rock and (roughly) tell what sorts of rock are down there...for oil purposes, the biggies are shale, salt, and sandstone. The geologists look for likely formations that would have trapped oil if it were there. Then you send an exploration rig to drill an exploration well. This isn't for producing oil, it's solely to see if oil's down there. They drill to the spots that the geologists said look promising and see what's there. If you hit oil or gas, great, you do more exploration wells to find the edges of the field, take samples, etc. and figure out what you've really got. If (more likely) you hit brine, then you plug the well with cement and leave. If the field both 1) has oil/gas and 2) has enough to make it worth producing and 3) is setup in a way that you can economically get it out then you create a production plan. A rig (often a different one) goes in and drills a bunch of production wells, installs the hardware to get the oil to the surface, and away you go. Deep sea/ocean rigs, whether production or exploration, usually aren't sitting on the bottom. They're just really big specialized ships. There's a kind that actually looks like a ship, unimaginatively called a drillship. Those are almost always dynamically positioned, they just hold position with thrusters. There's another kind that looks like a platform with fat legs, that's called a \"semi-submersible\". Those can be dynamically positioned or anchored. Production rigs stay on location for years, so they're not usually dynamically positioned. You can anchor them, or built a really tall platform to sit on the bottom (good up to a few thousand feet), or do some funky high technology anchors like tension legs and other exotic things that work like anchors but are slightly less annoying and more stable than spewing out tens of thousands of feet of anchor line."
],
"score": [
14,
10,
5
],
"text_urls": [
[
"https://youtube.com/watch?v=CvyP8KJl-gQ",
"https://en.wikipedia.org/wiki/Hydrocarbon_exploration",
"https://i.imgur.com/hZWjyRC.gif",
"https://i.imgur.com/BTLNbHQ.jpg",
"https://m.youtube.com/watch?v=r7G_zUFy-bk"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ide0q2 | Why do video games make you press a button after loading before you can see the main menu? | Technology | explainlikeimfive | {
"a_id": [
"g28cpn6",
"g28gsuc",
"g28ma71"
],
"text": [
"It might just be a long standing convention that many developers continue without giving it much thought. Back in the days of arcade games, the title screen would have the prompt to insert coin(s), which would typically change to Press Start, or similar, after credits had been loaded. (Inserting coins didn't necessarily put you straight into the game, as you'd press a different start button depending on which set of controls you were using - Player 1 or Player 2, for example). Home conversions of arcade titles obviously wouldn't ask you to insert coins. (Come to think of it though, given how keenly publishers embraced microtransactions in more recent years, I'm sure they would have if they could). Nevertheless, they often replicated the arcade title screen, complete with \"Press Start\" prompt.",
"It's so the game can tell which controller, and therefore which user is playing. Although it could be skipped if there is only one controller connected, or one user signed in, it's become a staple of the industry.",
"Console makers had a requirement that games have the players take an action within a short period of time so the console felt fast. They did not want players waiting for several minutes thinking something was broken or that the console was slow. So games would quickly load a \"press a buuton\" screen and then load the actual game. This became standard as good user experience. Let the player know the game is working before taking time to load."
],
"score": [
12,
11,
4
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ide5ly | How are voltages synced up between chargers and devices? | For instance, when charging a phone with a 5V USB, you have the charger pushing 5V 2.4A into the phone's battery, but the battery is at anywhere between 3.7V and 4.2V depending on state of charge. So does the device tell the charger that it needs say 3.9V and then the charger gives it that, or does the charger push 5V no matter what and there's a DC-DC converter in the phone that converts it to what the phone needs. Same question with Tesla superchargers. I know the Superchargers are 480V DC, but the Tesla batteries are around 380V nominal voltage. So does the Supercharger push 380V at first and then ramp up or does it push 480V steady and then the car has an internal DC-DC converter that gives it what it needs? | Technology | explainlikeimfive | {
"a_id": [
"g28dgqg"
],
"text": [
"There is a charge controller chip in the phone that takes a 5V constant voltage feed. It then imposes a voltage and current limit of it to feed it into the battery. For most of the charge cycle the battery charge is current limited to 1-2A (this inherently implies that the charging voltage tracks the battery voltage fairly closely). At the end of the cycle when the battery itself doesn't take that much current, the charging switches over to voltage limiting at 4.2V or so - the highest safe voltage for li-ion cells. If you want to know how Quickcharge (feeding the charge controller more than 5V) works, look at Hackaday: URL_0"
],
"score": [
3
],
"text_urls": [
[
"https://hackaday.io/project/26278-quick-charge-30"
]
]
} | [
"url"
] | [
"url"
] |
idekgs | how an electric car is ecologically and ethically better when the electricity is produced by gaz, fioul, etc? | Technology | explainlikeimfive | {
"a_id": [
"g28eo4p",
"g28eprg",
"g28exra"
],
"text": [
"Even if an electric car is charged by a fossil fuel grid, it’s net emissions per mile driven is still much less than the emissions of a gasoline engine. It’s not perfect, and there are still a lot of issues with electric cars (like mining the elements required for the batteries) but it’s better.",
"> most of it Put into contrast that while *most* of the energy in your country might come from non-renewable resources, **all** of the energy in a combustion motor comes from non-renewable resources.",
"* Electric cars can potentially be powered by renewable energy plants that are built in the future. A gas-powered car will burn gas until the day it’s sent to the junkyard. * Even if the electricity is generated by fossil fuels, it’s much more efficient (and thus more environmentally friendly) to have a single fossil-fuel power plant distributing electricity than to have thousands of individual fossil-fuel cars."
],
"score": [
10,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idfm3w | Why are people hating on Apple for removing Fortnite? | Technology | explainlikeimfive | {
"a_id": [
"g28n7zi",
"g28ljna"
],
"text": [
"People hate on Apple because Fortnite is a popular game and now people can't play it on their Iphone. Apple is free to do whatever they want with their apps store, the problem is that you can't install an apps on an Apple product unless it's by the apps store. This could be viewed as a monopoly and an unfair practice as people that choose the hardware from Apples (for example an IPhone) are pretty much at the mercy of what Apple decide to charge or what they accept or not on their apps store. People can't decide fuck apps store, I'm gonna get my apps another way, their only option would be to buy a new phone.",
"Because Fortnite is a very popular game. So people are hating on Apple for removing it so they can't use it on their iPhones and other devices. It doesn't matter that Apple was just enforcing it's rules. It only matters that they cannot use the app any more."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idi9ld | Why is the game Go so difficult for computers to master? | Technology | explainlikeimfive | {
"a_id": [
"g296d20",
"g2962zu",
"g2971ux"
],
"text": [
"Several, but two are the most commonly brought up. Imagine playing chess. When evaluating a move, you usually follow this pattern: you want to move one piece, so you try to figure what the best move your opponent can do after yours, then maybe you consider what you could do next. You're coming up with a plan, a strategy. Well, AIs are great at this. Problem is, in Go there are SO many possible moves even they struggle. Secondly, AIs love numbers. Usually, they look at a game board (the state of the game) and come up with a single number that values that board. A value that tells them how good that position is, how well they are doing. In Go it's hard to come up with this number, much more than, say, chess. My knowledge on the matter though is mostly theoretical, I studied it at the university but never got into the actual issue myself.",
"So, in general computer AI for board games utilize a set number of methods how to figure out the \"best move\", but the most common is some variation on \"Play a move, then play a move for the opponent, then play a move for yourself, and so on to a set depth. Pick the move that led to you most often getting in the better position\". Essentially they look ahead some number of moves and see what gets them closest to victory. This is all fine and dandy, until you get a board game that is not only fairly hard to evaluate (It isn't obvious how to tell if one board position is better than another), but each time a player moves they have a *lot* of options. A 19x19 Go board has 361 points you can put stones on when it's your turn. If we assume that on average each player has ~100 legal moves for their turn just looking ahead three moves (My move, your move, my move) requires the computer to evaluate a million different board positions on that last layer. Even a good computer struggles doing that in a reasonable timeframe. So, computers playing Go need a long time just to badly evaluate their position. Humans on the other hand are very visual thinkers, and we're really good at quickly assessing what moves are worth following and what moves can be dismissed out of hand. That intuition is hard to the very non-visual, non-intuiting computer. A computer can't easily tell off the bat a series of moves is always going to fail until it has already spent time evaluating it. As such Go AI remained an unsolved problem until the late 2010's, and even today it's not trivial setting up a decent GO AI in the same way you can just download a chess library and get a world-master AI for you website.",
"The approach to having a computer play board games has historically involved having the computer calculate the best move by looking as many moves ahead as possible. With chess, there are around 30 choices per move (16 or fewer pieces with some being able to move different amounts and directions), and many of those possible moves are obviously bad (like giving up a queen). With go, there are more than 300 possible moves in the early game, and most bad moves are considerably less obvious. The calculation for complexity is the number of turns to think ahead to the power of the number of possible moves per turn. So thinking 10 moves ahead in chess is approximately 10^30. Thinking 10 moves ahead in Go is 10^300. That's 270 more 0s... This complexity is what makes analyzing the game so hard for computers. By applying a modern approach of using convolutional neural networks to look at the game as a whole, the computer is able to only evaluate a few moves ahead, but with great precision the way a human can think."
],
"score": [
6,
4,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idl7fp | why we have over the counter painkillers but not OTC antidepressants or anti-anxiety meds? | Technology | explainlikeimfive | {
"a_id": [
"g29pwh1",
"g29rlg5",
"g29poh2",
"g2a2cy0"
],
"text": [
"OTC painkillers are pretty simple and hard to mess up. Their effects are very well-documented and consistent, and they have a relatively short half-life in the body. Wait a few hours and it'll all be gone, even if you have some kind of allergic reaction. None of that is true of antidepressants. We aren't quite sure how they work because we aren't quite sure how consciousness works. They have different effects on everyone, and most of them build up in the nervous system over time and take days or weeks to flush out if something goes wrong. Furthermore, they are given to people who are, you know, mentally ill. People who you want to keep checking up on in case something goes wrong. Prescription refills are a way to do that.",
"In addition to what the other people said. Anti depressants are medication you need to take over a long time, gradually increasing the dosis,in oder for them to work properly. You need to take them for a long time for them to even work at all and if you want to stop taking them you have to gradually decrease your dosis over a long period of time. If you decrease your dosis too fast you will get terrible side effects (speaking from experience). That's why you need to consult a doctor while taking these medications so they can tell you how to do it properly. You also need to account for other medication you are taking. I for example had to take into account the kind of birth controll pills I am taking because some anti depressants could make my birth controll stop working. Also anti depressants can have terrible side effects so you should regularly see a doctor while taking them so the doctor can evaluate wether the side effects are withing normal ranges or wether you should try taking a different kind of anti depressant. In short: there's a bunch of things that need to be accounted for when taking anti depressants so you need a doctor to do that for you.",
"OTC painkillers are very safe if used as prescribed on the label. Often with very little or no side effects. Antidepressants and Anti-Anxiety meds can have terrible side effects. Some cause people to get more depressed or suicidal. Some can give you paranoid thoughts (this happened to me once). Only a trained professional can monitor you closely and change your meds based on your reactions. Also, if they were OTC, there would be terrible cases of people over using them. Both are already (In my opinion) prescribed way too much. OTC Meds tend to be meds that are safe with little side effects, and don't tend to be abused.",
"Antidepressants often have terrible side effects; their use needs to be monitored by a physician. The most widely prescribed anti-anxiety drugs - benzodiazepines - are widely abused as recreational drug, Of the entire universe of available painkillers, only a handful are OTC. Most are prescription only because of the risk of addiction, overdose, and / or difficult withdrawl."
],
"score": [
28,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idmjzd | - Why sites need to know that you're not a robot? What is the point with captchas? | And why some are fine with just a click and others require you to "defuse a bomb" puzzle? | Technology | explainlikeimfive | {
"a_id": [
"g29zfhu",
"g2adncx",
"g2aotwt"
],
"text": [
"Programmer here. The issue is that there exists things called \"browser automation tools\" such as Selenium. These allow a programmer, like me, to program in a set of rules that tell the browser how to behave. You can do all kinds of things with these tools, including mass creating accounts on websites, making purchases, and scraping data. In some cases this isn't so bad, but most sites prefer to avoid this, so they use something like ReCaptcha to make you prove that you're a human and not a computer program. They still have flaws, but at the very least they make things much more difficult.",
"The ability to make bots that do things online automatically is potentially highly abusable. I could buy all the toilet paper on Amazon at the first sign of a pandemic, buy all the tickets to the next sports game for scalping, make it look like I have millions of followers on Twitter, etc. People behaving badly don't care about Terms of Service or illegality. But none of these sites really want that to happen and need some kind of defence, so you're asked to prove you're not a bot by doing something that is really hard for software to do but really easy for humans to do. Every making them has different styles, mostly pictures with distorted letters and numbers but some are more creative.",
"sites that accept user generated content may be victims of spam attacks by computer programs called bots. so to stop these bots they have to be able to differentiate between legitimate human users and bots. captchas let them do that."
],
"score": [
5,
4,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
idr0nj | How does the pump at the gas station know when to stop putting fuel in your car? | Technology | explainlikeimfive | {
"a_id": [
"g2at72w",
"g2bl8sq",
"g2bn23u",
"g2ayotn"
],
"text": [
"Up inside the handle there's a venturi nozzle (a smooth restriction in the tube) that causes a low pressure spot in the fuel line. That venturi is connected by a small tube to a hole near the end of the nozzle. The hole is on the side of the nozzle, not the big hole that the fuel comes out of. While you're pumping fuel the venturi pulls air into that small hole. When the tank gets full enough that the fuel level comes up to the end of the nozzle, fuel starts to get sucked into that little hole. Fuel is way denser than air. This causes a pressure change inside the handle that actuates a spring-loaded mechanism to shut off the valve inside.",
"[ URL_0 ]( URL_0 ) That's really helpful video to explain what's going on with some cut-away nozzles.",
"Can someone ELI5 when I buy fuel which is a different grade than the last guy how I’m not getting a hose-full of the former?",
"Basically the nozzle is initially being dipped into an empty tank which is full of air. When filled, the nozzle begins to be surrounded by liquid, which rushes into a small hole they intentionally put in the nozzle. After a short spell of black magic physicsry, the change in energy corresponding to fuel being sucked in to replace air is partially redirected to shut off the nozzle's fuel line. As mentioned by others, there are many readings and entertaining youtube videos on the venturi effect that would explain that black magic physicsry, but that would require a lot of words or maybe a ELI10"
],
"score": [
368,
34,
10,
9
],
"text_urls": [
[],
[
"https://www.youtube.com/watch?v=q3phjAQZdGg"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idrnfw | How the quickly flashing green light on the back of a Fitbit/smart watch works to check your heart rate? | Technology | explainlikeimfive | {
"a_id": [
"g2avsj7",
"g2ax6sj",
"g2bo0wz"
],
"text": [
"> Photoplethysmography. It’s essentially testing how much red or green light it can see when looking at the skin on your wrist. Blood is red because it reflects red light and absorbs green light, so when your heart beats, there’s more blood flow in your wrist, and more green light absorption. Between heart beats, there’s less absorption of green light. URL_0",
"All objects either absorb or don't absorb different colours. The colour of the object depends on what it does not absorb. Blood looks red because it absorbs all other colours but red. It absorbs green well (hence the green light). So one can shine green light on your skin and use a photodiode (a device to measure how bright a given light is) to calculate how how much blood is in your veins. When the heart 'beats', blood is pushed through arteries and veins causing them to expand. So it's something of a ripple effect in your veins. With this mechanism, during the 'beat' of the heart, the photodiode measures less light and during the interval between beats, measures more light. Put this on a timer and there you go, beats per minute (BPM) This is a very watered down explanation if at all correct. (to my understanding, it is)",
"I will also add that the light flashes because a chopped signal is easier to measure than a steady one. The chopped signal gives you a zero that you can reference to measure the signal. In practice, this is done with a light detector and something called a lock-in amplifier that turns the reflected light signal into an AM signal (like a radio signal) that encodes your analog pulse."
],
"score": [
28,
8,
3
],
"text_urls": [
[
"https://exist.io/blog/fitness-trackers-heart-rate/"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
idsoqx | How do contactless cards work? | Technology | explainlikeimfive | {
"a_id": [
"g2b1i3h"
],
"text": [
"The card reader emits a magnetic field via coil. The card has a tiny chip with a memory embedded in the plastic. The chip is connected to another coil embedded in the card. If the reader detects the magnetic response of the card's coil in its near field, it starts altering the magnetic field, powering the coil and the chip in the card. The reader now can read the memory in the card by magnetic field modulation and checks in whatever system behind it if the card is valid and triggers whatever purpose it is used for."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
idvfrj | When talking about 3g,4g, 5g etc and internet getting faster, how does it actually get faster? | Technology | explainlikeimfive | {
"a_id": [
"g2bgwkz"
],
"text": [
"It's different modulation techniques. How much data you can transfer greatly depends on how you encode it on the electromagnetic wave you're transmitting. 5G and LTE for example use Orthogonal Frequency-Division Multiplexing (OFDM). This basically means we are transmitting over several frequency channels in paralell."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
idwlx0 | What are bitcoins? | Technology | explainlikeimfive | {
"a_id": [
"g2bmxfq"
],
"text": [
"Bitcoin is a new currency that was created in 2009 by an unknown person using the alias Satoshi Nakamoto. Transactions are made with no middle men – meaning, no banks! Bitcoin can be used to book hotels on Expedia, shop for furniture on Overstock and buy Xbox games. [Learn more here.]( URL_0 )"
],
"score": [
3
],
"text_urls": [
[
"https://www.google.com/search?q=What+is+a+bitcoin%3F&oq=What+is+a+bitcoin%3F&aqs=chrome..69i57j0l4.16146j0j4&client=ms-android-google&sourceid=chrome-mobile&ie=UTF-8"
]
]
} | [
"url"
] | [
"url"
] |
|
idxpg1 | How can an oven that has a turbo mode cook food in half the time but at the same temperature? | Technology | explainlikeimfive | {
"a_id": [
"g2bua50"
],
"text": [
"A common way to speed up the cooking is to blow the hot air at the food so it heats up the same way wind feels colder. The air directly touching the food can cool down and if it’s not moved it can somewhat insulate it from cooking more."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
idy7hg | how can we generate purely random numbers? Is there a way? | Technology | explainlikeimfive | {
"a_id": [
"g2bxftw"
],
"text": [
"Quantum mechanical events (such as how long it takes an individual radioactive atom to decay) are entirely random, and by measuring them, we can generate truly random numbers. Non-random but highly complex systems can also generate \"random enough\" numbers, such as \"the temperature of your CPU right now times the duration since you last clicked the mouse plus the wind speed in this one random city I just looked up\" - all of that is theoretically predictable but functionally impossible to do so. There's one internet security company I know of that provides random numbers based on the movement of a wall covered in lava lamps."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
idyybo | Why can't Wi-Fi be transmitted the same why mobile service is, via a tower or satellite to make it widely available? | Technology | explainlikeimfive | {
"a_id": [
"g2c3eao",
"g2c353s",
"g2cepnm",
"g2cc7y6"
],
"text": [
"Wi-fi isn't good at penetrating things like walls and is pretty much line of sight, compared to cellular frequencies. Coverage comparable to the cellular network would require a lot of antennas.",
"Wifi is microwaves. If it were transmitted very far, the amount of power needed would cook anyone too close to it.",
"This is like asking \"Why can't cars drive on rails and go fast like trains?\" We have both cars and trains. We have both wifi and cell towers. Different things exist simultaneously.",
"Mobile phones do not use satellites that is except from receiving the gps signal. There is a limited amount of radio frequency that you can use. Wifi use a small range in the 2.4 and 5 Ghz ranges for the common types. There is only 3 non overlapping channels in the 2.4 GHz range and 24 in the 5 GHz range. So if you transmitted WiFi at high power so it covered a lot larger area you only have those channels to share. So you need to manage them so Wifi networks do not overlap and the you have exactly how mobile phone networks works. WiFi is fast because you have a large frequency range for each channels so you can transmit a low power and and frequency range that get absorbed a lot by the surrounding. So you might be able to receive Wifi signals from the housed coset to you but there is no interference with a house a house 100 meter away. So WiFi can be fast for everyone because it do not reach far so the same channel and be reused quite close to you with no interference. So if you could cover a city with a single 2.4GHz WiFi access points the result is that there is 3 Wifi networks that everyone would share in the city and the speed is terrible. If the range is like it is now it can be only people in your house that share a channel or you do that with your neighbours. So short range is a feature of WiFi and is why it works with lot of networks that do not interfere. The low range is why WiFi works in cities If you look at mobile network 5G will have a lot of small transmitters with low rage so there is fewer people to share the bandwidth and the speed increases for each uses. So mobile networks move closer to WiFi rand to increase the speed."
],
"score": [
14,
13,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ie56kq | Why is the glass panel of a PC case always on the left side of the case? | So I've been looking at getting a new PC case, typically I have my PC setup to my left. It seems that most PC cases are oriented to be placed on the "right" side of a desk or at least on the "right" side of the user. This isn't a huge issue, but I was wondering, is there a specific reason for this? & #x200B; Thank you in advance! | Technology | explainlikeimfive | {
"a_id": [
"g2d7hv6"
],
"text": [
"Motherboard positioning mainly. The ATX motherboard standard and it's related standards (nearly universal outside of some odd OEM prebuilts) has its I/O panel and expansion ports on the left side of the board, and it's uncommon (for reasons I am not fully aware of) to mount a board upside-down. As such, in a case, the board will always be on the right/bottom of the case if the I/o ports and expansion slots face the rear."
],
"score": [
18
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
ie65tq | How does face recognition on smartphones and other devices work? How does the program differentiate between a picture of you and your real face when unlocking it? | Technology | explainlikeimfive | {
"a_id": [
"g2dlfij"
],
"text": [
"It differentiates between the 2 because face recognition software takes a 3D scan of your face where a picture is only 2D. This prevents the most obvious way of circumventing the technology."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ie72ik | If our brains are somewhat analogous to computers, can computers become confused or mess up in math and other tasks like we do? | Technology | explainlikeimfive | {
"a_id": [
"g2dkpml"
],
"text": [
"Computers can occasionally mess up math due to things like supply voltage fluctuations or cosmic radiation particles hitting the wrong thing (this is why ECC -Error Correcting Code- RAM sticks exist: to recover the rare errors introduced into critical servers' memory by cosmic radiation) but they are much more resistant to errors than the human brain because they are drastically different in basic structure. A computer is made to do math and do it extremely well. We just contorted math into doing something similar to what brains do for artificial neural networks, \"AI\" or \"machine learning\" as it is colloquially known, although ANNs are just one type. They are still much worse at it than our brains, but they are close enough to be useful. Brains were \"made\" to control a meat puppet to navigate the world and survive. In that application math is entirely unimportant - it's a very neat little side feature our brains gained as they became more complex and able to reason about the world beyond foraging for food or trying to frick, and as such is very imperfect and slow at brute force number crunching."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ieeuoi | Can Face ID differentiates between identical twins? | Technology | explainlikeimfive | {
"a_id": [
"g2frc2z"
],
"text": [
"People have done tests, and no, it still unlocks with identical twins, it cannot differentiate, however this isn’t true for Touch ID"
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ieexv7 | Why do we have to point tv remotes towards the tv to get it to register, but not Xbox remotes? | Technology | explainlikeimfive | {
"a_id": [
"g2fpw7q"
],
"text": [
"TV remotes use a laser beam, and Xbox uses a radio antennae. Little less ELI5: TV remotes use infrared (IR), which is a kind of light that is not visible to the human eye. It acts kind of like a flashlight, but with different colors we can't see. When you push a button on the remote, it activates a certain (invisible) color (aka frequency), that is shown to the TV, and the TV knows what to do when it sees that color. The XBox however, uses BlueTooth. BlueTooth is more like a radio signal, it sends a high-energy signal in all directions for a very short distance (usually no more than about 33 feet). This means you can move your controller all over the place with out having to constantly point it at the console for it to work."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ieit0s | when I’m installing programs on a computer what does the “setup wizard” or “installation wizard” actually do? | Technology | explainlikeimfive | {
"a_id": [
"g2gwe1j"
],
"text": [
"before the wizards you had to manually type in all the information. what do you want to do where is the file located now you have to find or mount the cd and the hard drive. and tell the pc where it is. then tell the pc where you will put it. then you have to find the exe that installs the file and tell it to run. and stuff like that, before plug and play and install wizards came along almost nothing was automated. you would put a cd or floppy in and nothing happened until you did something. this is a very basic description but you get the idea."
],
"score": [
12
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
iej29p | Why haven't we managed to develop an easily-quantifiable unit for 'how much energy something has left' in rechargeable devices? For example "oh man, that phone call just cost me 5 Whatevers of phone battery" | Technology | explainlikeimfive | {
"a_id": [
"g2gxmjg",
"g2gznkr"
],
"text": [
"That does exist. We just don’t talk in amps and Volts unless you are an electrician, mechanic, scientist or electrical engineer.",
"Don’t you just use “percent”? “Can you pass me the charger? I’m on 12 percent”"
],
"score": [
16,
10
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
iejj2x | Why do wireless peripherals come with their own bluetooth dongle? Why can't my PC use one dongle to connect to multiple devices? | Technology | explainlikeimfive | {
"a_id": [
"g2h3hzz"
],
"text": [
"The dongles don’t USE Bluetooth, or they wouldn’t need the dongle. It, as far as I am aware, is a radio wireless receiver that also serves to decode the signal transmitted from the mouse. As to why each mouse needs their own, one may use slightly different frequencies or something, but if I’m not mistaken it mostly has to do with preventing interference. It wouldn’t make sense for me to be able to plug in a mouse, and suddenly my buddy with the same brand can control it. Plus, it’s a lot cheaper on computer manufacturers to pass on the costs of the receivers onto the mice companies, considering the user may not even use a wireless one."
],
"score": [
10
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
iekei3 | How do pulse oximeters guess the oxygen level in your blood? | Technology | explainlikeimfive | {
"a_id": [
"g2hfo3b",
"g2i7pet",
"g2hfxjp",
"g2hgq09"
],
"text": [
"It doesn't guess it, it's directly measured via light absorption. Oxygenated hemoglobin (HbO2) absorbs different wavelengths of light in different intensities than the non-oxygenated form (Hb). By using 2 LEDs with different wavelengths, you can work out how high the percentage of the oxygenated form is.",
"Technology Connections, a YouTube channel which looks at electronics recently had a video [explaining how these work]( URL_0 ).",
"They shine two lights through your finger and into a light brightness sensor. The color of the lights is different, one light will be diminished by oxygen rich blood cells and the other not. By comparing the brightness difference of the lights, the blood oxygen level can be calculated.",
"They measure the intensity of certain colors of light that go through your tissue. The protein hemoglobin in your red blood cells carries oxygen to all parts of your body. If you shine a light through the hemoglobin, its shadow (transmitted light) will be different depending on if it carries oxygen (oxygenated) or if it does not (deoxygenated). To be more specific, deoxygenated blood absorbs more red light than oxygenated blood. For near-infrared light (NIR), the reverse happens, oxygenated blood absorbs more NIR light than deoxygenated. By measuring the differences in these transmitted colors shining through your tissue during your normal blood flow pulses with a red- and NIR-colored LED, it's possible to determine the percentage of oxygenated blood vs. deoxygenated blood."
],
"score": [
14,
7,
5,
3
],
"text_urls": [
[],
[
"https://youtu.be/4pZZ5AEEmek"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
iepgm4 | Why cant we just have drones with infrared cameras alert california fire authorities the second brush fires start? | Technology | explainlikeimfive | {
"a_id": [
"g2ij2wm",
"g2ip1r3",
"g2iio9b",
"g2iiljk",
"g2iofhy",
"g2ijt6x"
],
"text": [
"I'm not sure you understand just how much forest and brush there is. Like, through the Sierras, there's a lot of places where you could walk in a straight line for a couple days, and not encounter any houses, roads, trails, or other signs of development. Covering all of the territory in any type of effective manner would take hundreds of drones. Even if you didn't cover urban areas, and populated spaces, where people are likely to report fires quickly. And that's ignoring the man hours and resources spent chasing false positives. Edit: really, pull up Google maps, and look towards the middle of Cali. You can probably skip the majority of the San Juaquin Valley, because it's pretty populated. Every once in a long while, there's a fire south of Bakersfield, before the grapevine. But it's not often a big deal. But west of I5 is pretty sparsely populated until you get to the coast. Same thing about 20 miles east of 99 and into the Sierras. Whole lot of land, whole lot of flammable material. Not a lot of practical ways to keep an eye on it.",
"They already do possible fire detection with satellites. You can even see the data in real time here: [ URL_0 ]( URL_0 ) The little orange suns are satellite hits (lots just south of SF by Big Basin), the little fires are confirmed, and the colored shapes show air quality. Zoom in to find them, and you can click them to see details.",
"The same reason it's hard to find a lost boat on the ocean. There's a lot of area to cover.",
"I'm going to go with cost and bureaucratic inertia. Your plan makes a lot of sense, but like a lot of things that make sense in the real world, the problem is getting the right people to act. The Forestry Service wouldn't have money in their budget for that kind of innovation, so they'd have to go to the State for the money. Now the problem becomes who is going to pay for it and what company is going to get the contract. Now comes the real fun. Who is going to operate the drones? Civil Servants or private contractors. What level of training do they need?",
"I think maybe satellite imagery would be more realistic, still that's a lot of ground to cover.",
"We technically could but that would require a number of things which cost money. 1) A buttload of drones. California is huge. evn with each drone seeing several miles you would need thousands. 2) A base station of some sort. Either the drone needs to be able to automatically swap its battery without human intervention or there needs to be 10x as many drones to allow them time to recharge. Or maybe even a worker here to swap batteries every 5-30 minutes depending on the design. 3) Network connection for the base station. That is a lot of satellite internet or new network cables that need to be wired. For that matter.... 4) Electricity. Lots of new powerlines have to be layed to cover every square mile of California. $$$$ 5) Bad weather. Storms, rain, and even wind could destroy the drones or at least cause guidance or control issues causing them to fail to return to the automated base station requiring workers to constantly fix things. 6) An actual fire. To detect remote fires, you must be in remote places. These expensive base stations, the infrastructure, and all the drones would be destroyed when an actual fire happens. 7) depending on altitude this could be a hazard to other aircraft. So, lots of problems. Most of them go away if you give up total coverage and give up real-time reporting. I'm quite sure someone somewhere is doing this on a small scale."
],
"score": [
43,
41,
24,
8,
6,
6
],
"text_urls": [
[],
[
"https://fire.airnow.gov/"
],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ieq6g1 | How did bridge builders of old ensure both ends of the bridge would perfect meet in the middle before laser measuring was around? | Technology | explainlikeimfive | {
"a_id": [
"g2iogzr",
"g2j4599"
],
"text": [
"Guide poles and ropes. You set up either poles or ropes on either side of the space you want your bridge that stretch the distance you need to cover, and then you start building between the poles/ropes. You can remove the poles/ropes after completion, but a lot of times guide poles would remain as part of the structure. Most bridges were smaller, and often they didn't start building from both sides, anyway.",
"Before lasers we used (and still do use) optical systems instead - in particular the theodolite. A theodolite is a device that measures angles - you sight down a small scope, and by using a few readouts on the theodolite determine the direction the scope is aimed, and the angle of elevation. If you have two known points (such as two starting points that you have positioned a set distance apart from each other), you can then use trigonometry to create a triangle between the two known points and the third you are measuring to and determine how far away Do this accurately enough and you can plot out all the locations and heights you want, allowing you to set out your structure."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
ieqcb4 | How does your charger charge your phone battery? | Technology | explainlikeimfive | {
"a_id": [
"g2ir873"
],
"text": [
"Batteries use chemical reactions to create a voltage and pushes the current in a certain direction. For rechargeable batteries, the chemical reaction can be reversed. By plugging into a wall, an outside voltage is pushing the current in the opposite direction and forcing the reaction backwards."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
ieqfjr | How can different radio frequencies (HZ) broadcast the entire spectrum of audible sound frequencies (HZ) simultaneously? | Technology | explainlikeimfive | {
"a_id": [
"g2iq9b7",
"g2iqlyu"
],
"text": [
"Basically, because radio frequencies are much much higher than sound frequencies. If it’s digital radio, like cell phone signals, it’s basically transmitting instructions in binary that tell the receiver “now generate a 44kHz tone”. If it’s analog, like AM or FM in your car, the radio signal is being altered (modulated) at the speed of the audio signal. Since radio frequencies are about 1000-1000000 times faster than audio, it takes only small changes in the radio signal to convey information at sound frequency. Rough rule of thumb is that your carrier frequency needs to be 2-3x faster than the highest frequency information you want to transmit to avoid weird aliasing problems. Radio is way way way higher than that.",
"There are two methods: Amplitude Modulation (AM) and Frequency Modulation (FM) What i'm gonna write down is basically a TLDR of this [video]( URL_0 ) AM: The radio wave is a constant frequency, but the amplitude (\"height\") of the wave changes in relation to the audio it's carrying. FM: The sound is instead encoded into slight changes in frequency. When your radio is tuned to a specific FM frequency, it's actually listening to a small band of frequencies around it."
],
"score": [
7,
3
],
"text_urls": [
[],
[
"https://www.youtube.com/watch?v=w3M4cqAMWQs"
]
]
} | [
"url"
] | [
"url"
] |
|
ierffj | How does Windows Defender differentiate a virus from "safe" files? | I ask this because sometimes viruses can be "xyz.js" (javascript) files and it made me wonder, how Windows Defender scans and determines "This, this file right here is gonna mess things up". | Technology | explainlikeimfive | {
"a_id": [
"g2lam4c"
],
"text": [
"Antivirus software primarily compares files on your PC to known viruses. So if xyz.js looks an awful like the stuff used in abc virus, Defender will flag it as dangerous."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
iet055 | How does an automatic transmission shift gears? And what makes the gears shift back "down" once the speed decreases past certain points? | Technology | explainlikeimfive | {
"a_id": [
"g2ja4xh"
],
"text": [
"Vacuum pressure Most semi automated things in older automobiles were done using the manifold vacuum pressure as an indicator of engine load. Modern ones are going to use a computer that watches the pressure and engine speed, but the principles remain the same. Air comes into the engine through the air intake, scoots past the throttle plate(this moves when you press the gas), enters the intake manifold, and is then pulled into the cylinders. At idle the throttle is mostly closed so the cylinders are sucking air out of the intake manifold and leaving it at a slightly lower pressure than the outside air. If you accelerate hard, the throttle plate will open up to let more air flow through and until the engine is up to speed the air in the intake manifold will be at the same pressure as the outside air because the throttle isn't really restricting the airflow But if you let off the gas it'll close the throttle but the engine will still be spinning fast and trying to pull in lots of air so it'll draw a strong vacuum in the intake manifold because the air is being heavily restricted. The transmission would sense these changes. If the vacuum drops to 0 then it should probably downshift to give you better acceleration, when you're up to speed and there's a strong vacuum then it should upshift to slow down the engine because you don't need that much power right now. As you slow down the pressure difference between intake and ambient will decrease and it will down shift to put you into a better gear for your slower speed. The actual shifting of the gears is done by clutch plates that can connect the Sun, Ring, or Planetary gears to the Input shaft, output shaft, or lock them in place. Almost all automatic transmissions use [Planetary gearsets]( URL_0 ) so you don't have to try to mesh the gears like in a manual."
],
"score": [
12
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Epicyclic_gearing"
]
]
} | [
"url"
] | [
"url"
] |
|
ieunfv | How do touch screens know the difference between an object and your finger? | Technology | explainlikeimfive | {
"a_id": [
"g2jhaal"
],
"text": [
"Short answer:They don't. Long answer is that they work by generating an electric field and can detect when that electrical field is grounded when you touch it with something that can easily conduct current like your finger. Things that don't conduct current won't trigger your screen, things that do will."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.