q_id
stringlengths 6
6
| title
stringlengths 4
294
| selftext
stringlengths 0
2.48k
| category
stringclasses 1
value | subreddit
stringclasses 1
value | answers
dict | title_urls
listlengths 1
1
| selftext_urls
listlengths 1
1
|
|---|---|---|---|---|---|---|---|
baqvpn | Why is it that videogames are sometimes suddenly delayed extremely close to their release dates, while this is usually unheard of when it comes to films? | Technology | explainlikeimfive | {
"a_id": [
"ekdh8aq",
"ekdh2ag"
],
"text": [
"Games can have unexpected things in them that aren't found until the last minute. These things tend to be bugs that need to be patched out; given the nature of programming, testing fixes may take an extremely long time if the bug runs deep enough. Meanwhile, films don't really have bugs. If a film is on the cusp of being released, all that can be done is cleanup.",
"The short answer is that the games industry is awful. The long answer is that studios are always expected to make deadline even when its very clear that its not likely. Studios will often times be given ludicrous launch dates to coincide with a release schedule set forth by marketing. This is why \"crunch\" time is so prevalent in the industry, because when they are behind schedule they aren't given the option to delay until they are failing to ship copies."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
barjof | How do digital scales work? | Technology | explainlikeimfive | {
"a_id": [
"ekdk5yf"
],
"text": [
"There's a peice of metal inside the scale that gets squeezed when you put weight on it. When the metal gets squeezed, its electrical resistance changes in a predictable way. So, by measuring the electrical resistance of the metal, the scale can determine the amount of weight. This is called a strain gauge."
],
"score": [
10
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
batgtd | Why does a video game cartridge require a battery to store save data, while something like an SD card doesn’t? | Technology | explainlikeimfive | {
"a_id": [
"ekduk8w",
"ekdujau"
],
"text": [
"SD Cards uses flash storage which didn't exist in a viable form back when cartridges where still being used. There were EPROMs and similar erasable rom technology but those tended to be very expensive and had limited rewrites. The most viable and cost effective method was to have some low power DRAM with a battery to keep it running. Even early PDAs and small computing devices (like the Palm and Psion) used battery backed RAM rather than truly permanent storage for their file systems.",
"It's different tech. Being able to store data without a constant electrical charge is a fairly new innovation. Old cartridge games had memory in them similar to the RAM in your computer. When it loses power, it loses everything it had stored. Solid state is able to keep data in storage without electricity, which is why newer cartridge systems like the 3DS and PS Vita just use special SD cards."
],
"score": [
9,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bavhql | Since we will eventually hit a wall of reducing the size of transistors on a computer processor, what else can we do to improve its performance? | Technology | explainlikeimfive | {
"a_id": [
"ekekx8d",
"eke8ptb",
"ekec31j",
"eke95v3",
"eke9bts",
"ekef3nx",
"ekeb4kp",
"ekenyaw"
],
"text": [
"There are a bunch of technologies that will continue to push performance forward for a while: * [Asynchronous logic]( URL_5 ). You know how CPUs are clocked, e.g., 3 GHz (3 billion cycles/second)? Using a clock makes it much easier to synchronize and schedule the work the processor is doing. Unfortunately, the clock itself takes power and needs to get routed around the chip, and all of the work the CPU does has to get chopped up into chunks that can get done within one clock cycle. [In 1997, Intel developed an asynchronous, Pentium-compatible test chip that ran three times as fast, on half the power, as its synchronous equivalent,]( URL_1 ) but didn't commercialize it because designing asynchronous logic is much harder. * [Photonic interconnects]( URL_3 ) would eliminate the propagation delay of signals across the chip. * Exotic semiconductors like [Gallium arsenide]( URL_4 ), [Carbon nanotubes]( URL_0 ), and even [diamond]( URL_2 ) can be clocked higher than silicon. Silicon has the advantage of being cheap, easy to manufacture, easy to purify, easy to manipulate with \"dopants\" to change its electrical properties, easy to insulate (SiO2), and being very well understood. * Widespread use of programmable hardware (FPGAs). The CPUs we use today are general-purpose. They are optimized to handle a wide variety of tasks, but truly excel at none of them. Nowadays a computer has lots of fixed, specialized hardware that you use only some of the time to decode video, render 3d graphics, decrypt data, and so on. If instead most of a computer's hardware was reconfigurable, it's as if entirely different chips, optimized to do different functions, can be swapped in and out on the fly.",
"I'm thinking that a fundamental understanding of how an electron moves between two points without passing through all points in between is going to be the next big advancement. That could theoretically open the door to having no wires.",
"There are a few avenues available once we can no longer brute Force our way with simply more calculations. 1) more efficient coding. Figuring out the elegant solutions to problems rather than simply doing tons of small approximations. Or if you have to approximate (quite common in many situations) you do it with methods that require fewer overall steps. 2) dedicated chips designed to do a specific type of calculations. We already do this. Graphics cards are optimized on a hardware level to do certain calculations very efficiently. Newer ones even have specific \"physics\" chips to take some tasks away from the main PC to figure out things like light paths, smoke, and fabric blowing in wind. This can apply to more tasks. 3) parallel processing hardware and software design. Break a task up to different chips so they all do one small part. Then organize and deliver it as a whole when they're all done. Wierd solutions: use radio signals to connect parts of the chips or motherboard rather than wires. It takes time for an answer to skip from one side of a chip to the other for further communication. So simply broadcast it wirelessly to use the fastest thing we can: light. Optical circuits that don't use electricity, but instead use light. This takes very different materials and processes to make, and it will be some time before it comes to complete with modern CPU on speed, cost and size. But theoretically much faster. Moving away from binary coding. Having only on or off in each piece of information is limiting if simple to engineer and code. Moving to a system that had more states (trinary with off, on and kind of on) can help with processing speed if done properly. But also not easily integrated into our current system.",
"There are a few things that can be done. First, architectural improvements. Processors have individual steps they can do called instructions. As time goes on, these instructions tended to be able to executed in fewer clock cycles on average. You can also add new specialized instructions that are useful for certain cases. Intel and AMD processors use the x86 architecture, which provides instructions to do operations such as addition on multiple numbers at once, which can greatly speed up things where many values are operated on the same way. Second, we can add more cores. This can be done by using multiple processor dies or by enlarging the dies to hold more cores. This is what makes a super computer better than a normal computer in basic terms: they use a whole lot of cores which can do many calculations in parallel.",
"In a way that is already reached. The clock speed increase a lot slower today the it did in the past so the result was that you started to add more and more cores Look at [40 years microprocessors trend data]( URL_0 ) and notice how the frequency have remand relative stable since \\~2005 Single thread performance have still increased because the designs get better and better . So when you can't create smaller transistors the rate of speed increase will slow down but you can still improve the speed by changing the design to more do it more efficient.",
"An interesting possibility I have seen is making processors three-dimensional, or replacing electrons with photons (aka making the data travel by light instead of by wire)",
"Very simple: streamline code. Make it efficient en cut out the sloppy parts. Don't program an Os that has everything like modern Windows, but go barebones and add what you need. Basically go back to the minimalist code of way back then. Oh, and cut ads, telemetry.",
"We can make transistor a lot smaller, but there is no longer a guarantee that they will function as intended. They would operate probabilistically not deterministically. As in it probably gave me the correct result. We could simply adjust our way of thinking about computers to accommodate this, or deployed some compensation mechanisms. There are several error correction algorithms out there, especially in the digital radio communicates field. We could also simply parallelize the signal through multiple processors and take the consensus as the result."
],
"score": [
135,
22,
20,
14,
8,
4,
4,
3
],
"text_urls": [
[
"https://spectrum.ieee.org/nanoclast/semiconductors/materials/carbon-nanotubes-outperform-siliconbased-transistors-at-the-same-scale",
"https://www.technologyreview.com/s/401226/its-time-for-clockless-chips/",
"https://electronics360.globalspec.com/article/11910/high-performance-diamond-semiconductor-devices-coming-soon-akhan-s-miraj-diamond-technology-granted-key-patents-and-trademarks",
"https://en.wikipedia.org/wiki/Silicon_photonics",
"https://en.wikipedia.org/wiki/Gallium_arsenide#GaAs_advantages",
"https://en.wikipedia.org/wiki/Asynchronous_circuit"
],
[],
[],
[],
[
"https://www.karlrupp.net/wp-content/uploads/2015/06/40-years-processor-trend-625x409.png"
],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
baw4qg | If we pointed a radio telescope at Earth from space, what would we see? | Technology | explainlikeimfive | {
"a_id": [
"ekefxie"
],
"text": [
"It depends on what frequency you choose. Unless you stay in the [Water Hole]( URL_0 ) you only see an opaque ball. There is also a narrow optical band where you can sometimes see some of the surface, but that's not a radio telescope. In the Water Hole (between 1.42 and 1.67 GHz), you don't see much unless something happens to be pointed at you having just passed some satellite. Then you'd see highly structured data, in a short burst before the planetary rotation sweeps the signal off you. It would be an indicator of technology, but it wouldn't tell you much in that short burst, without any context. Just enough that you'd mark the place \"inhabited\" on your species' star charts and go someplace else with your interstellar spaceship."
],
"score": [
5
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Water_hole_\\(radio\\)"
]
]
} | [
"url"
] | [
"url"
] |
|
bax7s0 | Does it make a difference when buying an older film in HD/SD? | Today I pulled up my Amazon account in hopes of buying and watching Dead Poet's Society when I found myself in a dilemma. This 1997 film was offered for $9.99 SD or $17.99 HD. In the past when it's a dollar or two difference I usually splurge but with it being double the cost I gotta know... does it matter? What is the difference? With a film that I watched so fondly for the last 20 years in what I would guess be SD somehow be even better, and how/why? | Technology | explainlikeimfive | {
"a_id": [
"ekep83o",
"ekeol5s",
"ekeo6p5",
"ekeodik",
"ekeyahg",
"ekepqsk"
],
"text": [
"On a related note, bit-rate can make a difference as well. In my experience, a low resolution film with low bit-rate \"looks better\" than a high resolution film with low bit-rate. I'm not sure if this is true though - so if someone who actually knows their shit can correct me, please do!",
"\"Dead Poets Sociaty\" were shot on 35mm film. Although you can not compare film with digital quality a 35mm film will have better quality footage then HDTV can provide. So although you may get some artifacts from the original film most of the degraded quality is from when the film were scanned and compressed into an HD format. Even at 4K there will be a lot of artifacts from the scan that were not present in the original film. It is only when you get to 8K where the film is the most limiting factor of the quality. But more expensive movie productions used 70mm film which would have better quality then 8K digital.",
"Depends on how much you want to have the best visual experience. It will look clearer in HD, but you might not care for a movie like this since it's not especially visually focused.",
"Yes, the quality varies. You will notice a difference, the number of pixels per square inch in HD films are much higher than SD films, thus making the image quality of HD films way higher because it shows finer details. Also films from the 90's aren't considered \"old\" from a filmmaking perspective,you will notice these quality differences even in films from the 60s. I suggest watching any YouTube video to make up your choice,in fact, here is [the trailer of the film]( URL_0 ) you mentioned. Set the quality to 480p (That's the SD quality) then switch and set the quality to 720p or 1080p (That's the HD quality).",
"If it's something that was re-released on blu-ray at some point then chances are the digital version has also been remastered. When they re-release movies on a new format they ideally go back to the source (in this case the film print) and digitize it. It will look much better than say a VHS cassette tape or old TV broadcast if that is how you are used to watching it. SD is like DVD quality while HD is blu-ray quality. It will have a higher resolution and potentially a newer surround sound mix. You will only notice a difference if your TV is also HD. If it's on the small side or just for your computer, I bet the SD version will do you fine. Another consideration is if you are streaming it over a slow internet connection (rather than downloading it) that could affect playback quality as well.",
"Maybe. I went to the Amazon site and they really, really don't make it clear what you get if you order SD. Here is the deal. SD normally indicates 480. HD indicates 1080. Normally. If you have an HD tv (which you probably do, they have been standard for like a zillion years now) then without a doubt, always get 1080. It will look better. But what are you getting? Well, depends. What you might be getting is something called an 'upscaled' picture. It is just math where they use a program to duplicate pixels from the 480 version so it looks nice on the 1080. But this is a movie that won oscars that people still talk about. It was a movie that was filmed on FILM and not digitally. In that case they take the film, use a scanner and create a brand new 1080 print that is then converted digitally. These are the real deal. There is detail in this that does not exist in the upscaled image. My understanding is the scanning process isn't really that big of a deal - assuming you have the prints to work off of. Sadly, in your case I have no way of predicting what you are gonna get when you rent it. Me personally, I wouldn't think twice about renting the HD version. Unless I was using a 480 tv, or some other device that made me question the sanity of paying for HD (like a cell phone). ----- Truth is, me, personally, I would rent it from URL_0 ."
],
"score": [
4,
4,
3,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[
"https://www.youtube.com/watch?v=4lj185DaZ_o"
],
[],
[
"dvd.com"
]
]
} | [
"url"
] | [
"url"
] |
bayhad | How is video and music data stored digitally when there isnt any power in the device (battery dies)? | Technology | explainlikeimfive | {
"a_id": [
"ekey04a",
"ekexvo4",
"ekfda8a"
],
"text": [
"When you toggle a light switch at home and the power goes out, it remains toggled in that direction until/when the power is restored. The 0/1 toggle stays where ya put it.",
"Solid state memory (also known as flash memory), is what they use in most newer devices, is what they call non-volatile memory and doesn’t require a constant, external power supply to store the data. RAM is volatile memory. Magnetic and solid state mediums are considered stable, or non-volatile memory (NVM). Edit: the type of transistor flash memory uses will change state from a 1 to a zero depending upon how the voltage is applied. Its state is persistent after the voltage state is removed, so until the opposite voltage is applied, it stays the same. So solid state memory consists of these persistent types of transistors whereas magnetic mediums use magnetically raised or lowered segments to represent that binary code. RAM uses a constant voltage to maintain the state of the transistors which is why when that current is removed it loses its data.",
"Spinning hard drives store their 1s and 0s in magnetic fields. Like how a paper clip retains a magnetic field when near a strong magnet for a bit, the read-write head uses electricity to create a magnetic field in the disk. The disk plates are made up of a material that, like a paper clip, can have it’s magnetic direction changed and locked in place. Writing data is forcing changes in the direction in small spots on the drive. Reading is just measuring the direction of those spots. If the field is strong between two neighboring spots because they are amplifying each other then it’s a 1, else they cancel each other and it’s a 0. Optical disks, like a CD or DVD, use a laser shined on a disk. Pressed disks (like what you get music and movies on from the store) have physical dents that scatter the light, or flat spots, which reflect the light back into a sensor. Writable and rewritable disks (CD-RW) have a laser melt a thin plastic like layer inside the disk, and the temperature it’s heated to determines if it reflects or not."
],
"score": [
7,
6,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bb43hr | Phone, laptop, TV, Tablet has WiFi adapters. Why there no simple one-click way to transer files from one to another? | Technology | explainlikeimfive | {
"a_id": [
"ekg8qgh",
"ekga5f8",
"ekgd84g",
"ekgtrkf"
],
"text": [
"There are many different file sharing protocols. (S)FTP, SAMBA and HTTP are all examples. Even accessing Reddit right now is as easy as clicking a button. Different devices are not always configured to receive and send data to different devices, Ex. Sending files from an iPhone to an Android is notoriously tricky as they have no initial support to communicate to each other. But with a third party service such as SMS(IM) or a third party app utilising Bluetooth these challenges can be overcome.",
"Why are there 12 competing wireless file transfer standards?!?!? Surely we can come to an all encompassing standard. . . . . . (6 months later) There are now 13 competing standards.",
"Companies has historically used incompatibility to box groups of people in their own environment. Be it gaming consoles, operating systems for PCs, web browsers. Only now we see a change when the money no longer comes from the device itself but the users data. Just look at microsoft offering windows 10 basically for free and now supports linux in windows.",
"Wifi is just like a telephone. It connects things together. It doesn't know or care who's calling, what country they're from, what language they speak, whether they're ordering a pizza, chatting about the weekend or organising a drug deal. Although the telephone *enabled* people to speak to each other, it didn't give them magical powers of *understanding*, and it didn't force them to *agree* with each other on tricky issues. So a room full of wifi-enabled devices is like a room full of people from many different countries and cultures. They have the *ability* to speak and to hear, but unless they share a common language and agree to be nice to each other, you're either going to have fights or a bunch of bored people who can't/won't talk to each other. Even if you have a good interpreter, you still can run into problems when people misunderstand due to cultural differences. In this room full of people, we don't know many of them and we trust even fewer. You might let your BFF read your diary. You would let your mother into your bedroom but you'd die of embarrassment if your mother read your diary. Your teacher might be allowed inside your house but not your bedroom. The school bully wouldn't even be allowed in the house and you'd probably cut your own wrists if they read your diary! Now think about your \"one click\". How much information needs to be in that one click? That one click needs to: * Establish a common language between devices made by companies that want to keep their trade secrets, and would prefer that you didn't give your money to a competitor * Ensure that the other end of the call really is your friend * Ensure that the call can't be listened to by anyone except you and your friend * Ensure that your friend can only see/hear what you want them to see/hear That's an awful lot that needs to happen inside \"one click\"!"
],
"score": [
17,
16,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bb667g | How can a plane measure it's altitude (and how was it done a 100 years ago without our current modern tools)? | Technology | explainlikeimfive | {
"a_id": [
"ekgjw2r",
"ekid0ta",
"ekgjwqh"
],
"text": [
"100 years ago was the age of biplanes. The primary methods for determining position were \"look at the ground\". Not long after, planes started using barometers to determine altitude. In the modern day, radar is also an option.",
"An Altimeter is has a little metal accordion shaped canister inside. It's called an [aneroid wafer]( URL_0 ) The canister is sealed with an amount of air trapped inside of it. As you climb and descend, the difference in air pressure between the surrounding atmosphere and the air trapped in the wafer causes that wafer to expand and contract, just like a balloon does when you carry it to different elevations. The rest is merely calibrating that wafer to move a needle on a display that you can read. To compensate for the different pressure from weather systems, there is a knob on it to adjust it to the current local pressure. At altitudes above 18,000 feet, you're moving too fast to keep it accurate across weather systems, so everyone sets their altimeters to the standard 29.92 inches of Mercury. This means that everyone is no longer reading their *actual* altitude, but everyone has the *same* incorrect reading, so they don't hit each other. This is why everything above 18000ft is a Flight Level, and everything below 18000ft is Altitude.",
"They would use a barometer. You'd have to know what the pressure at your starting altitude was( it always changes) and then set your BARALT accordingly."
],
"score": [
10,
5,
4
],
"text_urls": [
[],
[
"https://www.cfinotebook.net/graphics/avionics-and-instruments/altimeter/altimeter.jpg"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
bb8h8d | How does prioritising traffic lights work? Those that priorities ex. buses over private cars | Technology | explainlikeimfive | {
"a_id": [
"ekgycvw"
],
"text": [
"You have active radio transponder on the buses or some other way to detect them and change the switching of the light so it let them trough first. So the the idea is if a buss is detected on road A then next road that will have a green light will be A and leave it green until the buss has passed trough the intersection. The cycle the normal way trough the roads in the intersection"
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bb8msz | Is there any difference between forcing a computer shutdown with the power button vs manually clicking shut down? | Technology | explainlikeimfive | {
"a_id": [
"ekgzh16",
"ekgzmfd",
"ekgzxnc"
],
"text": [
"Yes there is a difference! Imagine falling asleep, this is like clicking shutdown, your brain stores all the information from the day and you remember it when you wake up. The computer does the same thing, before it turns off it stores all the information so that it can be remembered the next time it turns on. Forcing a shutdown is like getting knocked out, you will not remember what happened when you were knocked out, your brain wasn't able to store the information because it wasn't turned off properly. When the computer is forced to shut down, all memory in RAM is lost and not stored. Neither action hurts the computer, only the information stored in RAM, and both actions could be used for benefit of the user. Let's say you messed something up and don't want the computer to remember it, you'd force a shut down so nothing is saved to the start up files allowing you to correct what you've done. Hope that helps!",
"Depends what you mean by “forcing”. Pressing the power button will initiate a shutdown just like clicking shutdown in Windows (note that it’s possible to change the function of the button to shutdown/sleep/etc). Pressing the button for 4 seconds will force the machine to power off immediately, which isn’t a good idea unless the computer has locked up and it’s the only option.",
"Holding the power button long cuts the power. No buts no nothing. Everything not saved and bolted down is gone. That's a good thing when everything is stuck and slow and stuff, and the computer has a chance to begin with a new white sheet. If, on the other hand, the computer was busy saving stuff and was in the middle of writing a file, that file is now corrupt. Simple text files or so are fairly recoverable up to the point where they were saved, but more complex binary files usually not. If that file is an important one, a computer can have a problem. Most modern systems have some failsafes installed for when that happens, however. Shutting down by clicking in the menus or just clicking the power button gives the computer time to finish whatever it was doing and going down orderly.(shutdown) In some cases it doesn't even really shut down. Sometimes it just stops doing much but keeps a little bit of power going to the ram and keyboard, so you can resume very quickly. (suspend) In other cases it copies the contents of the RAM to disk and goes totally dead. When it starts up again, it copies that back into RAM, and you can continue from where you started. (Hibernate)"
],
"score": [
52,
36,
7
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bb9ycc | How can you remove an object from a photo and there be more of the photo behind it? | I see this all the time in photo editing apps. I understand computers a decent bit, cameras not at all. But I just can't figure it out. If you take a photo of a beach, but there is a tree in the middle, how can you later go back and remove that tree and the beach suddenly be there as if that was the photo you took all along? & #x200B; [Here]( URL_0 ) is a good video of what I'm talking about, if you scroll down to the "Get rid of unwanted objects in your photos" heading. Which is about 2/3 of the way down the page. | Technology | explainlikeimfive | {
"a_id": [
"ekh9p6f",
"ekha3df"
],
"text": [
"There's a clone stamp tool, that allows you to \"clone\" the background from next to the object over the place, some cleaning up and smoothing and then you have \"removed\" the object.",
"Actually there is no photo \"behind\" the thing you erase, it's just blank space. What editing softwares or people do is to fill the blank space with a thing that resemble the space and merges together with the picture evenly. This can be done many ways, like taking another part of another image that looks like the are you want to fill, or to paint the blank area, manually or with AI. You can understand more of that watch a few tutorials about that."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bba2b6 | When almost all of them have 16:9/18.5:9/21:9 screen ratios, why do smartphones still mostly have 4:3 camera sensors? | Technology | explainlikeimfive | {
"a_id": [
"ekhb0t7",
"ekhb97a",
"ekhdqtl",
"ekhavlz"
],
"text": [
"It makes sense to capture essentially a near square image with as much information as possible (i.e. high pixel density) and then allow the devices/users to crop and render these images however they want.",
"It would need a larger aperture lens. A lens is going to produce a circular optical image. Fitting that over a 4:3 sensor uses most of that circle. To have a 16:9 or even more unequal ratio you would have to have a larger circular image with sufficient diameter to fit the longer dimension. The other way would be to keep the lens but make the pixel size smaller to get the sensor fully within the image circle. Smaller pixels equal smaller light- gathering preformance.",
"Because that's still the standard for still photography even thought video screens are 16:9 or similar. Phone cameras aren't just for on-device use.",
"Photography uses different formats than video. Traditional photography used to be 4:3 or 3:2 . This carried over to video a few decades ago but now everyone wants wide screens."
],
"score": [
19,
7,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbb7xa | Why are there no smartphones with E-Ink Displays? | Technology | explainlikeimfive | {
"a_id": [
"ekhlrx7",
"ekhpwem",
"ekhk8nw"
],
"text": [
"e-ink doesn't come in full color, and is extremely slow to update. That's fine for reading a book. Absolutely unusable for scrolling through a webpage, contact list or anything else. Now one could have a second e-ink display for things like the time and a list of notifications. But that takes work to create, and if people don't think it's an awesome idea and rush to buy it, it might not be a winning proposition.",
"It's not just Black/White, it's also 1 FPS update. While that's great for text and phone, you couldn't control the camera that way, not to mention watch cat videos. What's awesome in an ebook, from a power consumption perspective, is that there is almost nothing else going on while it waits for you to signal \"next page\". Alas, in a phone there is all that radio/Internet work that would still mean you have to charge every day. The charge once per month phone isn't in your future, unless your future looks like the DynaTAC.",
"Phone companies have tried prototypes but nothing really gained traction. OLEDs today can do practically the same and still give you the color when you want it."
],
"score": [
7,
7,
5
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbc54v | What problem do digital certificates solve in public key encryption? | The classic example: Alice sends message to Bob. Alice uses Bob’s public key to encrypt the message, and Bob uses his private key to decrypt the message. Where do digital certificates come into play here? | Technology | explainlikeimfive | {
"a_id": [
"ekhtcxr",
"ekhrhc0"
],
"text": [
"Public key cryptography doesn't require certificates, certificates are only there to ensure that Alice is actually talking to Bob Without certificates Alice asks Bob for his public key to send him a message, but Bob's evil twin Rob intercepts the message and gives Alice his key instead. He still passes all her messages on to Bob so she won't notice but he makes a copy of each message before passing them along Certificates let Bob prove he's Bob. When Alice asks for his certificate with his public key she'll see his friend Sven vouching for him, when she checks out Sven's certificate she'll see Dave vouching for him. She knows Dave, everyone knows Dave! If Dave says Sven is trustworthy and Sven says Bob is the Bob she wanted to talk to then Alice knows her messages are only going to the person she wanted to talk to. This makes it a lot harder for Rob to get in the middle as he'd have to fake a certificate rather than just intercept the initial messages",
"Digital certificates authenticate the source of a message. The certificate is the public decryption key that matches with the private encryption key known only to a verified entity. So if you get a message from Verisign that you can decrypt using Verisign's certificate, you can be sure it was actually Verisign that sent it. Since no one else has access to their private key, no one else could have encrypted the message such that it decrypts with their public key."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bbdfbo | What is the one thing that causes things to clip through one another in video games and why is it so hard to fix the issue? | Technology | explainlikeimfive | {
"a_id": [
"eki1oj4"
],
"text": [
"> What is the one thing that causes things to clip through one another in video games. There is no one things. There is literally thousands of different bugs that allow for no-clip glitches. Sometimes its just as simple certain walls not having collision. Adding hitboxes to objects takes time, and if you assume a player will never interact with an object there is no real reason to add one. Things like the ceiling of levels often times dont have hotboxes, if the game lacks the vertical mobility to get there. Other times it may require an animation that forces your character into a certain direction and orientation. Doom for example always puts your character a set distance from your opponent at the end of a glory kill. This means that if you hug really close to an enemy with your back to the wall the animation will put you through the wall at the end of it. Essentially teleporting you through the wall. Other times it may simply be a matter of going so fast that you your individual movement never actually touch the wall. If you think of your character as simply teleporting as a set number of pixels , and if you are moving fast enough you can move teleport through walls. There are also glitches that involve you despawning your own hitbox. For example, in the ratchet & clank game if you start a level on the same frame that you fall out of the map, the game wont know where to put your hitbox. This allows you to essentially no clip through any wall. There are also glitches that involve trigger skipping. Games dont load the entire map at the same time and sometimes things with physics, like doors, wont spawn until you get to a certain part of the map. If you can find away to avoid that trigger the door will be there, but its physics wont load and you can just walk right through. These are just the ones i can think of off the top of my head. Depending on how the game is coded there can be thousands of possible ways to make it so your character can move through objects."
],
"score": [
18
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bbhqwe | how do apps share data with other apps? | I recently added “sugar free twizzlers” to my food log app. I don’t even really like twizzlers. I opened my Instagram and I continue to get adds for twizzlers. I understand how google will present me ads based on my search history, but how are third party apps sharing info with other third party apps? | Technology | explainlikeimfive | {
"a_id": [
"ekiyeys"
],
"text": [
"Typically app writers make a deal with an advertising service. When you do certain things, they send a description of what you did to that service, so the app can show you relevant ads. However, that service in turn may also be working with additional apps, so the ads show up on multiple apps."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bbkij9 | the difference between Array VS list | Hello guys, new to programming and just don't understand it. | Technology | explainlikeimfive | {
"a_id": [
"ekjefrc"
],
"text": [
"As /u/EgNotaEkkiReddit wrote, an array is simply a block of data. Usually fixed size (can't resize it without creating a new array and copying the items to it), with N elements stored sequentially in memory, numbered from 0 to N-1. A list is any sequential collection of items. You can add items to a list, remove items, sometimes even move items around. Unlike an array, a list can have different implementations: * The actual data can be stored in an array, so it's easy to access any item in the middle of the list (you can ask for item #4 in the list for exapmle), but hard to add and remove items unless it's from the end of the list. This for example is known as `ArrayList` in Java or `List` in C#. * The list can be a linked list - each item in the list holds a reference to the next item on the list (as in /u/EgNotaEkkiReddit's example). This makes it easy to add or remove items from the middle of the list, but difficult to access items (in order to get to item #4, you start from #0, from there to #1, to #2, etc.)"
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bblcyv | Wouldn't passwords be exponentially more secure if websites let us select them without restriction? | It seems like a website requiring my password include A, B, and C gives anyone hoping to gain access a starting point. My first hotmail password was yaga and hotmail never asked me to change it. I figured that was my most secure password at some point because new accounts had password requirements, and nobody would ever guess at that point that my password was 4 letters and nothing else special. | Technology | explainlikeimfive | {
"a_id": [
"ekjo8hx",
"ekjiv1d",
"ekjm8f4",
"ekjj6eo",
"ekjntpw",
"ekjk5d3"
],
"text": [
"> nobody would ever guess at that point that my password was 4 letters and nothing else special. It takes any laptop made in the last 10 years under 5 seconds to run trough all passwords of length 4 or lower. That password was your weakest password by a large margin. The point of having password requirements is because if you don't people will pick supid passwords like \"password\" or \"Steve123\" or \"abc12345\", passwords that will appear on every password dictionary ever created and will be the first things hackers trying to sniff out your password will try. Remember, hackers aren't trying to guess your password one attempt at a time. They employ programs that can guess a couple million passwords every second. The \"Starting point\" advantage is not as large as you think it is. Sure, having a set starting point allows you to ignore a million passwords, but there are still billions of passwords that just barely pass the requirements. The more requirements you makes it exponentially harder to guess even the 'simplest' passwords. edit: rewording.",
"I mean saying (password must contain a number/uppercase letter) isn’t gonna give anyone much of a “starting point”😂 stop being paranoid man, HYPOTHETICALLY SPEAKING.... it’s much easier to guess “yaga” than SuckMyLeftNut69",
"With no restrictions, too many people would select something too short or simple and thus easily hackable. Still better to have limits/requirements to ensure they are complex enough.",
"People don't try passwords one by one. They use machines and other technologies to crack passwords, or even attack databases or disrupt the path to gather information from there. Websites don't want you to keep using the same password because of database issues and actually want you to be safe. Some sites won't even load or have many protocols protecting their connection with yours (https, browser checking etc.). Making only text or short passwords can be cracked. There is no limit to try either in most cases. It's just a matter of packet delivery and sniffing it. Therefore every password is, eventually, crackable. But F4=5)#74bG & %rod83hdieh00000000000000000000 would take significantly longer to crack instead of a simple, 4 letter password. Length, diversity and reusing a password matters significantly.",
"Most of these replies miss the point that putting a requirement on a password reduces the possibilities and makes a password more brute-forceable than an unrestricted password of the same length. I won't name the organization, but I previously had a position that required me to access systems around the globe. The organization had very strict password requirements to the point that it soon became apparent that most sites came up with slight variations on the same \"complex\" password as very few easily remembered passwords could meet all the requirements. I have also encountered organizations that had downright senseless requirements, like 6 lower case letters and an 8 character exact length.",
"A company I used to work for had shitty cybersecurity measures in place. I was bored on an overnight shift and found that I had access to literally every document that the company had ever created. On one file on the network, I found a word document that listed the username and password to every employee. I'm fairly certain it was legit because mine was accurate. My passwords have been complex even before websites started making these requirements. In high school, a common password that I used with everything was a sequence of 27 numbers. Looking at this list (and the fact that I was able to access it) made me realize how little a lot of people understand about technology. The passwords for many of the older people were things I could have guessed, like the name of the director's hometown she was always talking about. So no, I don't think that they would be more secure because the average person probably doesn't know how to select a password that a computer program would find more challenging to hack. Even the 27 number password, which I thought was tricky at the time, would be simple because it lacks a variety of character types. Although, most wouldn't guess someone's password is that many numbers."
],
"score": [
9,
5,
4,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bbm0in | how do websites and search engines show results by "relevance"? How does the computer learn that? | Technology | explainlikeimfive | {
"a_id": [
"ekjomjt"
],
"text": [
"Bob Page, the guy who Google's \"page rank\" is named after, came up with a way of tracking how many other web pages link to a particular page, as well as how many times a particular term appears and/or is used as a paragraph title.. In other words if you search for \"Brian Addams\", you're going to get his Wikipedia page or IMDB page first, because every news article and entertainment page that talks about him will carry a picture, with credit link, to one of those two pages... so a lot of pages link to a page, giving it a higher Page Rank than say, the Facebook page of someone who happens to be called \"Bryan Adams\". As for the actual mechanical method for collecting this data, they use small applet like bots (called either spiders or robots) that literally just follow links all day, and keep tabulated records of where they end up. (The actual methodology however is one of those closely guarded secrets they guard closely)"
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bbnp7n | why does AC in the car feel colder than air outside, when external temperature is colder than AC setting? | Technology | explainlikeimfive | {
"a_id": [
"ekk31a4",
"ekk0exn"
],
"text": [
"Setting the A/C to 66 means it is trying to get the overall internal temp of the vehicle to 66, but to do this means using much cooler than 66 degree air to mix with the warmer air until it drops to the desired 66. Additionally, you fell the moving air, vs. more calm air outside, and moving air feels colder -- reason why winter temps are often reported with wind chill in addition to air temp.",
"AC also lowers humidity. When it's lower humidity, that's when sweat can evaporate off better (the air can only hold so much water). The sweat evaporation actually pulls the heat off."
],
"score": [
7,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbox3h | Why won’t “old phone” be able to work in a 5G network? Do we have to get new phones when 5G becomes a more prominent thing? | Technology | explainlikeimfive | {
"a_id": [
"ekka04f",
"ekkcaqb",
"ekkauea",
"ekkjwei",
"ekkcuwp"
],
"text": [
"The way I like to explain it: Think of network technologies like languages. 5G speaks Arabic. 4G speaks Chinese. 3G speaks English. Your phone now only speaks Chinese and English. You will need a new one to understand Arabic. It gets more complex than this, in a technical sense, but the concept is the same.",
"One thing nobody's mentioned yet is that existing 4G infrastructure isn't going away anytime soon so there's no rush to upgrade your phone unless you specifically want 5G",
"5G uses a different part of the EM spectrum than existing phones’ internal antennas as well. It’s like trying to have a conversation with a fax machine with your primitive human mouth. EDIT: A DSL modem would be a more accurate simile.",
"3G and 4G coexisted long enough that almost all 3G phones were junk and out of service anyway. By the time 4G is ready to die you'll likely have a new 5G phone anyway.",
"to answer your Q, 5G requres a 5G modem which your current phone does not have. like blu-ray and DVD. they ar both disks, but they are not the same, and need specially created harware to make use of it."
],
"score": [
16,
7,
5,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbpla0 | When security/researchers say they see a large scale hack "in real time" what exactly are they seeing? | Technology | explainlikeimfive | {
"a_id": [
"ekkfwp2",
"ekkfk4h"
],
"text": [
"Traffic. Those that know what to look for in the traffic are able to determine what communication is actually happening. One simple possibility is that you could be suddenly seeing large amounts of traffic outbound and find that data is being exfiltrated to an unknown destination. You may see in the traffic that a machine connected to a website and suddenly signatures are being tripped due to command and control traffic, for example, where an unknown machine is attempting to control yours.",
"Usually, they are seeing packets on a network flowing from the command and control computers used by the hackers to the victim's computers (and/or malware running on the victim's computers)."
],
"score": [
7,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbqryn | What's the difference between classifying internet as Title II or Title I? | Technology | explainlikeimfive | {
"a_id": [
"ekktaaf"
],
"text": [
"Title II is the \"Common Carrier\" standard like the phone company. Anyone operating a telephone service has treat all calls equally and cannot give priority access. Otherwise, they could charge you twice as much per call for mom and your girlfriend than calling anyone else. Companies laying new phone lines and infrastructure are mandated to share, but are allowed to charge strictly regulated usage fees to any other companies looking to piggyback off of their lines. Title I is for \"information Services\" companies, like cable and TV companies. Their communications are one-way, so there doesn't need to be as many regulations. The Internet blurs the line between the two. It can be used for two-way like I'm talking to you right now, but it also can be used for streaming video from your cable provider. ISP's would prefer it to be less regulated, and users would benefit from it being open. If Internet Service Providers can be classified as a Title II provider, the FCC will be forced to mandate that all internet traffic be handled like phone calls, selling data access at the same price for everyone. A good counter argument is Netflix and Youtube. The 4 major Video streaming services account for over 50% of the total data used during the US Primetime. Without Title II protection, ISP's could charge Netflix more for being such an extreme user. After all, if Amazon's delivery trucks accounted for 60% of our highway traffic, it would make sense to levy an extra tax on them for the use and abuse of our roadways. This sounds reasonable at first, but then consider that ISP's like Charter are often attached to their own streaming platforms. They have a profit incentive to set Netflix's bandwith to dialup speeds on their own network, while charging double for their streaming service that also happens to be the only one that works on their networks...which is also the only network in town."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bbqymm | How are Formula One cars so fast with a V6 turbo engine? | I know a V6 Turbo is really good but how do they go to 200 MPH and back to 0 in 6 seconds? I know it has something to do with the insane down force that the cars have but even then its still crazy with all the technology is in the car. | Technology | explainlikeimfive | {
"a_id": [
"ekkr2jt",
"ekkyzml",
"ekkrl1s"
],
"text": [
"F1 cars are some if not the most extreme cars on the planet. The cars generate tons of aerodynamic downforce which pushes them against the track to massively increase grip. This prevents the cars from skidding and flying off the track at those speeds and helps in acceleration and breaking. The tires are slicks with extremely sticky compounds (at temperature a Pirelli tire is as sticky as chewing gum) to generate more grip. And the engines generate near up to 1000 hp. The stopping power is a combination of using heat resistant carbon brakes that can generate a lot of stopping power, engine breaking from the ICU (I forget if this is legal these days), and electric braking from the MGU-K that is mounted to the transmission.",
"Also these cars are super light to capitalize on what power the ehnies) engines have. Literally just a frame, fiberglass and an engine.",
"Downforce is more useful for cornering at speed that accelerating/braking. Braking performance is mainly a combination of massive high grip tyres, massive high end brakes and little weight. Note that the tyres are usually softer than normal car tyres, giving far more grip but wearing out very quickly. I don’t know all the details of acceleration as I’m not really big into F1, but lack of weight will be a big advantage. They also have very high revving turbo engines that can produce a lot of power compared to their size/weight. Of course F1 engines are pretty temperamental and have complex starting procedures and regular rebuilds so you can’t really get something similar in a road car (although the new Aston and Mercedes hyper cars seem to be getting surprisingly close)"
],
"score": [
5,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bbr1nv | how do dishwashers work? | Technology | explainlikeimfive | {
"a_id": [
"ekkrw8f"
],
"text": [
"They spray a lot of hot water around (and some soap) through small moving nozzles which builds up slightly pressurized jets of water. A little bit like a small army of Smurfs armed with power washers. It does this for usually about half an hour to an hour depending on your model and settings, then it dries everything using a build in oven element, to warm everything up just warm enough that the water evaporates off (this only works for ceramic, glass and metal stuff... stupid plastic Tupperwear still is full of water cause you didn't put it in upside down and its plastic.)"
],
"score": [
15
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bbt3wj | How can we edit DNA if it’s so small!? | Technology | explainlikeimfive | {
"a_id": [
"eklae8p",
"eklpwfy"
],
"text": [
"We use really small tools! & #x200B; Keep in mind that eventhough DNA is very small, it is absolutely necessary for an organism to have a full access to it and to manipulate it with critical accuracy. A single mistake, and the whole cell can become cancerous! (it usually commits suicide before that happens, it's called apoptosis). To do so, cells have specialized \"tools\" (tool=protein) that can unzip/dupicate/fix DNA with an amazing precision. Most of these \"tools\" don't really EDIT your genome, since it remains untouched during the lifetime of most cells. But some organisms developped tools that can actually cut, add or delete bits of your DNA (most common examples: transposons which are basically parasitic genes, retroviruses/retrovirii/whatever you want to call them...). By using these tools in a clever way, we can edit the DNA of any living organism in any way we want. There are limitations, but they keep being pushed back as we discover new tools. Have you heard of CRISPR-Cas9?",
"In vivo (life) or in vitro (lab setting) because there are different tools for each? In vivo, like how others pointed out, we can use a bacteria's \"immune system\" (CRISPR-Cas9) to do it. In vitro we boil the DNA, cool it down, introduce an error via an error-prone, heat-resistant copying protein (e.g. TAQ polymerase) or RNA primer with an error, copy it, then cool it down. There are other methods as well but the these are either the most common or most talked about."
],
"score": [
17,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbtir5 | Why was the United States the only country to use semi-automatic rifles in significant numbers during WWII? | Technology | explainlikeimfive | {
"a_id": [
"eklbzy5",
"eklhj0g"
],
"text": [
"Pretty much everyone had a semi-auto rifle in development or limited deployment by 1939, but the European powers were already at war by then, and trying to swap out millions of service rifles in the middle of a war is extremely expensive. The US had a few extra years to get the M1 Garand into production and get the bugs worked out.",
"The Soviet Union what the firs major nation that had a semi automatic that was intended to be a the standard infantry rifle as the AVS-36 but with limited production until it was replaced wit the SVT-40 that worked better. There was 1.5 million SVT-40 produced during the war compared to 5.4 million M1 Garand. So 1.5 million automatic rifles is a significant number in my book. Germany produce 400 000 Sturmgewehr 44 that is a fully automatic assault rifle during the was and it is a significant amount. So I would argue that the premise of the question is not correct. The SVT-40 never become the standard and Soviet union had a lot of Mosin–Nagant rifles from before the war and it was simpler to produce the the SVT-40 and there was established manufacturing lines. They also realized that long range engagement that you can do with a full power rifle is not that common compare to short range so they produced a lot of submachine gun like PPSh-41 with 6 million produced where some was after the war. At the end of the war \\~50% of the frontline troops had the submachine guns. They also hade the PPS submachingun with 2 million produce primary for vehicles crews and support troops. German infantry tactics before the war was based around the machine gun and infantry with Karabiner 98k was there a lot to carry ammunition and to protect it. They also observe that combat is often at short range so they increase the amount of submachine guns and later assault rifles. & #x200B; So US enter the war later and have a working full power rifle cartridge semi automatic rifle cartridge as the standard weapon. US had before the war and after it priorities accuracy at long range with full power cartridge and you can see the after the war when other NATO countries experiment with intermediate rifle cartridges and still the 7.62 NATO become the standard. The move to a intimidate 5.56 NATO is a lot later. USSR with the 7.62×39mm that is a lot smaller and lighter adopt a intermediate cartridge back in the late 1940s. You can see the same during the war when the other countries produce and use more submachine gun the the US. Today most nations including the US uses intermediate rifles cartridges in select fire rifles. So you could say that in WWII Germany with the Sturmgewehr 44 was on the correct path. The manufacturing is a important part that is easy to forget. You have to make the gun and a better gun that you cant make enough of is not a option. Germany had a good FG 42 designed for paratroopers but it was to expensive to produce. It was not until the Sturmgewehr 44 with a lot of stamped parts instead of complex milled part they could manufacture enough to supply the general infantry. & #x200B; If combat ranges was longer and submachin guns was not as useful as they where you would lily have seen more full power semi or fully automatic rifles in WWII. Submachine guns have the advantages that most of them are simpler to produce then a semi automatic full power rifle and at close range they are better. So for large part of the war a submachine gun is better then a M1 Garand as you have larger magazine, can carry more bullets and have higher rate of fire. There was situation where the M1 is better but in general if you look at the production cost and how combat in WWII was submachine gun was a great option. I suspect if there was in single individual weapon from WWII select to equip a army with the Sturmgewehr 44 would be the best option. & #x200B; So it is that US entered the war later and that the the other sides moved more to submachine guns that is the large part of the explanation. The M1 production started in 1937 but they had some problems with it and there was redesigned in 1940 and the production rate is high in early 1941. So the weapon was not ready when WWII started. So countries that planed for war like Germany experimented with semi auto before the war but there was non good enough early enough so the only reliable rifle they could produce was bolt action."
],
"score": [
17,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bbv4jq | Why do you have to wait a few seconds after unplugging something before plugging it back in? | Technology | explainlikeimfive | {
"a_id": [
"eklpgeg",
"eklpuwg"
],
"text": [
"It has to do with capacitance. When you unplug something for a reset you let it sit for 30 seconds so all power gets drained from the circuit and cache gets cleared.",
"Mechanically, there is no reason, you can unplug something and plug it back in as quickly as you're capable. If, however, your were unplugging it for a **reason** and the reason was to **reset** the circuit to its initial conditions, then you have to wait for the capacitors that buffer the power supply to drain. Alternating current goes +, 0, -, 0, +, 0, ... and you don't want your gadget to die when the line voltage crosses 0. So, the device contains capacitors to provide power during the crossings. You don't have any way to know when the capacitors are empty, unless there is a light or something. However, very, very few electronics designers would include capacitors large enough to power the circuit for more than 10 seconds, to save money. By waiting 30 seconds, you're giving yourself some safety margin in case larger capacitors were on sale when the power circuit was built."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bc0ojp | Why is it almost impossible to break a 256 bit encryption? | Technology | explainlikeimfive | {
"a_id": [
"ekmun1o",
"ekmv70g",
"ekmvg14"
],
"text": [
"The best way to crack an encryption key and that is ‘brute-forcing,’ trial & error in simple terms. So, if the key length is 256-bit, there would be 2^256 possible combinations, and a hacker must try most of 2^256 possible combinations before arriving at the conclusion (Typically, it takes around 50% keys to get the right combination). On paper, 2^256 may seem like a normal number, but don’t you dare underestimate its power. 256-bit will have 115,792,089,237,316,195,423,570,985,008,687,907,853,269,984,665,640,564,039,457,584,007,913,129,639,936 (78 digits) possible combinations. Now talk about timescale. A trillion ( 10^12 ) seconds is very roughly 30 thousand years. This number is roughly 10^77, so you would need to test 10^65 keys per second to be done in 30 thousand years. Or test 1x 10000000000000000000000000000000000000000000000000000000000000000000000000000000 cases a second to be done in 30 thousand years.",
"It is because of the length of the 256 bit code. & #x200B; If I had a 2 bit code, there are only 4 options (2\\^2) and it wouldn't take you long to guess the right encryption. If I had a 30 bit code that means there are 1 billion options (2\\^30) and although it might take you a long time to guess the right number, a computer could try every combination in about a second. & #x200B; A 256 bit encryption is 256 binary (1 or 0, only two options) characters. This means there are 2\\^256 possible codes which is 10\\^77 possibilities. This means that a computer trying every possibility has too much work to do. Even if a computer is able to guess 1 billion (10\\^9) different possibilities every second it only means that the computer is able to try * 10\\^9 guesses per second (or about 10\\^16 guesses per year) * If the computer did that for a billion straight year it would have tried 10\\^25 guesses * So basically a computer has a 1/(10\\^52) chance of guessing the correct 256 bit encryption in 1 billion years * That's the same odds as winning the powerball lottery 6 straight times & #x200B; So a 256 bit code is so long that all the computers in the world working together could never find the right encryption.",
"The way encryption works is that, ideally, the only way to decrypt the file is if you know the correct key, and the only way to find the key if you don't know it is to guess it. With 256 bit encryption, there are 2^256 keys available, that means you multiply 2 by 2 by 2 by 2.... and so on, and the end result is a number with 77 zeroes. Just to put this into perspective: A year has about 30 million seconds, that is a number with 7 zeroes. If you task a billion computers which can each guess a billion (9 zeroes) of these keys per second to crack a 256 bit encryption, they would be able to guess 30000000000000000000000000 keys, which is nothing compared to the 10000000000000000000000000000000000000000000000000000000000000000000000 possible keys in total. Even if you put them in a time machine to warp them to the beginning of our solar system, they would not be done guessing by the time our sun is burnt out. So really the only way to ever crack encryption like that is to find a weakness in the encryption algorithm itself, or to find an entirely new type of computer which is just that much faster."
],
"score": [
39,
6,
5
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bc1bs6 | what is ray tracing and how does it work. | Technology | explainlikeimfive | {
"a_id": [
"ekn0bjw"
],
"text": [
"Former game developer here, This is a technique used to render 3D. The idea is for each pixel on your screen, you cast a virtual ray of light - you draw a line straight out into the 3D world until it hits a polygon. You then calculate how that line reflects off that polygon and cast another line. You repeat this process until you draw a line to a virtual source of light in your 3D world. Knowing how light gets from the source, back to that pixel, knowing the virtual surfaces the light virtually reflects off of, to get there, the \"materials\" and and their colors, you can figure out the color and intensity of that pixel. You do this for every light source in the scene, blend colors and intensities, and you can apply more elaborate effects to make the image more... Well, whatever you want it to be. It's very compute intensive, you're basically trying to run a virtual photon simulation. If you want to do this for a video game, you're asking to run this simulation 60 times a second. And if you want to get even crazier, you can run this simulation for every sub-pixel, since your screen is made of pixels, and each pixel is composed of 3 light emitting elements in red, green, and blue. So triple the workload. I mean, it all depends on the affects you want to produce, if we're talking a video game, or a movie where you want the results to look real, or surreal, or cartoonish... There's no limit to how sophisticated you can get with this (or really any) technique, if you have enough compute time and power to throw behind it."
],
"score": [
20
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bc1kzp | How do people type in mandarin on normal-sized keyboards if it has thousands of unique characters? | Technology | explainlikeimfive | {
"a_id": [
"ekn1pdw",
"ekn1m8d",
"ekn271x"
],
"text": [
"In japanese you type the phonetic sound of the character and the software gives a list of possible kanji you might want. There are also methods of free hand drawing the character if the one you want doesn't come up. It takes the drawn version and matches it to the character you want.",
"There are different input methods for mandarin. The most common one uses pinyin, which is a phonetical representation of mandarin characters. You begin to type the pinyin and an autocomplete box shows up and you choose the right character if it is ambiguous.",
"Every Chinese character has a pinyin, which is an alphabetisation that can be phonetically read aloud. For instance, 你好 (meaning hello) would be spelt “nihao” on a keyboard. Or 炒面 (meaning fried noodles) would be spelt “chaomian”."
],
"score": [
8,
7,
6
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bc5f3l | How did they convert petabytes of data into an image of a block hole? | Technology | explainlikeimfive | {
"a_id": [
"eko2ooa"
],
"text": [
"URL_0 So here is a ted talk by the computer scientist who did that part of the work. One of dozens of scientists who worked on this. I think she does a pretty good job of explaining it. The first thing you have to know is that the further away or smaller something is the more light you have to collect to be able to see it. Think of it like this, the larger the mirror(or lens) the greater the magnification. So in order to be able to see a black hole, we need a mirror as big as the earth which we obviously don’t have. What we do have is many radio telescopes around the earth. So basically they combined the data from the different telescopes over time (because the view changes as the earth spins). This is the computer science bit. They took their data and then used computers to make the image. They did this by using training sets of pictures to teach a computer what an image is and used that program to make the black hole photo that we have all seen :)"
],
"score": [
8
],
"text_urls": [
[
"https://www.ted.com/talks/katie_bouman_what_does_a_black_hole_look_like/up-next?language=en"
]
]
} | [
"url"
] | [
"url"
] |
|
bc6284 | Why don’t magnets affect Phone screens the same way they do television sets? | I only ask because I noticed on my wallet-phone case there’s a small magnet that keeps the case closed, and sometimes it will be resting against my phone but doesn’t seem to do anything. Why is that? Follow up question: Do magnets still affect Televisions like they used to? | Technology | explainlikeimfive | {
"a_id": [
"eko297k"
],
"text": [
"Cathode ray tube televisions direct photons with magnetic fields. Changing that magnetic field changes where the light goes, and thus screws with the picture. LCD screens don't use magnets to control where the light goes, so magnets don't affect them. No modern computer monitors and televisions are CRT screens, so magnets won't impact them, either."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bc62ju | How do radio stations determine how many listeners they have? | Technology | explainlikeimfive | {
"a_id": [
"eko2zuf"
],
"text": [
"In the UK radio station listeners are polled by an organisation called RAJAR. Basically householders are sent a survey and asked about their listening habits such as when they listen, how long for, which stations and so on. This data is the compiled and sent back to the stations, for a fee of course. This tells them that X numbers of people listen at certain times to certain shows and for a set amount of time. Stations may also do this sort of survey themselves but it basically boils down to they ask people if they are listening or not and it is all self reported. So I could say I listen to a show religiously every day, even if I don't. This only really applies to traditional (FM/AM) radio, internet based stations have more real-time information on how many people are listening to the stream based on IP addresses and so on."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bc6qiv | Why is the chip reader preferred over swiping your card? | Technology | explainlikeimfive | {
"a_id": [
"eko7rz7"
],
"text": [
"Chips in cards are more secure than swiping the magnetic strip. At this point the magnetic strip is trivially easy to read, but the chip sends a code that's only ever used once, so even if you can copy the chip you wouldn't necessarily be able to get the codes it would use."
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bc9dgj | What happens when a file is downloaded vs uploaded, and why is uploading so much slower than downloading? | Technology | explainlikeimfive | {
"a_id": [
"ekossqj",
"ekoxzjz",
"ekoyxkv"
],
"text": [
"Download: you receive a file Upload: you send a file Uploading is only slower because most consumer internet connections are not symmetrical (download bandwidth is greater than upload bandwidth) Edit: typo",
"Your router and ISP service provides a limited connection to the internet. Let's say you are given a 10mb/s cable to you. If we split this Bandwidth into even Upload/Download streams, synchronous. You will have 5Mbps Upload with 5Mbps Down. This is basically bare minimum to enjoy a single streamed show, tho expect some annoying buffering. The cool thing is, you can also upload the same stream to the internet at the same time. However, how often do you really stream or upload anything compared to what's being downloaded from the internet? Networking companies realized this early on, and now provide Asynchronous Internet connections for residents. Adjusting the 10Mbps example, we would see 8Mbps Down with 2Mbps Up. This new arrangement is still enough for common upload needs, like file backups or even a basic web cam. However, now we can stream a TV show without issues, plus browse most websites at the same time. Which is a more common everyday use case for homes. Otherwise, there's not much difference between Downloads and Uploads for everyday users to worry about. A business generally provides content for consumers on the internet, and will need a business internet connection that provides higher Upload Speeds, as well as Download speeds for everyone (internally & externally)",
"Getting to what some other people have said, which is that your internet bandwidth is not split evenly between up and down: The reason for this uneven split is because most of the time when you're browsing the internet, most of what you're sending up is pretty small because it's just the requests for whatever it is that you'd pulling back down."
],
"score": [
16,
10,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bcgfz9 | How are clothes for activity made sweat wicking and feel cool/comfortable despite heavy sweating? Why aren’t all clothes made to handle sweat like that? | Technology | explainlikeimfive | {
"a_id": [
"ekqfann"
],
"text": [
"The material is more expensive than cotton or blends. For instance the company that makes the Under Armor textile makes a wound dressing that if you put it on one way and put fluid on it, it passes through to the wound. If you put it on the other way, it pulls fluid out. All due to the way it’s woven and the components. They also put silver in some as an antibacterial. Gore Tex was originally for coating wire. Now it’s in a lot of clothing products, even heart grafts."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bchsgu | Why do solar calculators that have been in low light display random characters on the screen, rather than go blank, or zero, and are unresponsive till a "Clear" is pressed? | I have a picture of mine here. [ URL_0 ]( URL_0 ) | Technology | explainlikeimfive | {
"a_id": [
"ekr07b3",
"ekr09fx"
],
"text": [
"first, let's talk memory. calculators have a bit of internal memory made up of what are essentially fancy switches that are configured to trap electrons (physical form of electricity). most simple calculators use an old, cheap type of memory called volatile memory. this type requires a constant source of power. if it looses power, the electrons are set free and the memory blocks forget everything. (this is why most calculators and old game cartridges have batteries.) now, solar panels are not simple on-off devices. the output power is based on the light level. so in low light, it may not put out enough power to keep the memory energized. but (and here's the fun bit) it may generate enough to *almost* power the memory. some of those electron traps lose power while others remain energized. the memory then degrades into a corrupted state. so what you are seeing is the calculator trying to make sense of this corrupted memory. the calculator doesn't know that the memory is corrupted so it needs you to clear it manually to restore functionality.",
"The electronics in the calculator require a certain amount of power to work correctly. If the power coming from the solar cells is below that, the electronics can start behaving erratically, because some of the transistors will have a difficult time telling if they should be on or off. The circuits aren't off, because there's still some power, but they're not behaving correctly. This can result in a random display like what you see, but also the part of the calculator that actually does the math might be in a completely confused state. When that happens, even if the power levels go back up, the calculator might not start working because its internals are still confused from the power dip. The clear button sends a signal to the calculator telling it to reset all of its internal circuits to a fresh state (for instance, clearing all memory and displays to 0). It's possible to make a calculator that detects when the power has dipped and have it reset itself when the power comes back up, but that requires extra circuitry that might add to the cost of the calculator."
],
"score": [
17,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bciy3e | How do they know what molecules look like? | I've never taken a chemistry class. Here's my starting point. The periodic table of elements is a thing. The elements are arranged by their atomic weight...?? I don't know how they know what the atoms weigh, but let's move on. Each atom is composed of protons and neutrons surrounded by cloud of electrons, besides the subatomic particles that make them up. Atoms bond together to form molecules. They are bonded through uhhh... electrical charge?? And maybe some gravity in there for good measure?? You don't have to go too far in depth for these things if you don't want to. I'm sure Wikipedia can help me out on those. So far I've been reading about the history of molecular geometry on Wikipedia, and they made a lot of progress from the 1700s to 1800s. Here's what I'm really getting at: How did they know in the 1800s how many atoms make up a certain molecule? It's not like they could see it through a microscope. How do they know they're hexagon shaped? I'm here in this century and all of this is beyond me how someone could just figure that out, you know? | Technology | explainlikeimfive | {
"a_id": [
"ekrcc0n"
],
"text": [
"> I've never taken a chemistry class. Oof. Which country doesn't require this by law? > The elements are arranged by their atomic weight...?? I don't know how they know what the atoms weigh They are arranged by the number of protons in their nucleus, and their atomic mass (or atomic weight) is based on the protons and neutrons. To measure the mass of a proton you can measure the charge and then shoot individual ones past a field of known strength to measure the deflection and determine its mass. > Atoms bond together to form molecules. They are bonded through uhhh... electrical charge?? And maybe some gravity in there for good measure?? Basically just charge. Gravity is way too weak to factor in significantly and the strong and weak nuclear forces are too short range. > How did they know in the 1800s how many atoms make up a certain molecule? They could try to break it up and measure how it behaves in various conditions. It varies depending on the substance. > How do they know they're hexagon shaped? Figuring out the shape often involves careful calculations of the bonding forces and the expected resulting angle of connection between the involved atoms. Also the shape of large scale crystals might give a clue."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bcm555 | what does the 'frozen' button on the toaster change? | I eat bread slowly so I freeze it, then when I make toast I pop it in, push it down and press the 'frozen' button but what does it actually change? | Technology | explainlikeimfive | {
"a_id": [
"ekrsph2"
],
"text": [
"I’m no toaster expert, but I bet it lowers the temperature of the coils so that the bread can defrost and heat up evenly through."
],
"score": [
12
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bcnlml | How do guitar pickups work? | Technology | explainlikeimfive | {
"a_id": [
"eks4ogq",
"eks489j"
],
"text": [
"Guitar pickups are bar magnets. The magnets are wrapped with a coil of wire and this makes them an \"inductor\". Electric strings are usually made of nickel, which is a metal that interacts easily with magnets. So the metal strings vibrate and those vibrations are felt by the pickup because the pickup is a magnet. The energy is felt as a (very small) voltage. The voltage is then carried through the wire coil and through to the amplifier. The amplifier feels just the small voltage vibrations and uses that as information to replicate it as a large voltage vibration.",
"It’s essentially a magnet... the magnet “picks up” the vibrations from the metal strings and converts it into an electrical signal that your amplifier... well... amplifies it into vibrations from the speaker That way we get the nuances of strings vibrating but not the accoustical echoes like a hollow guitar... it also makes pick slides sound cool 😎"
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bco442 | Why can't we have a universal format for all video files? | Why so many ? why not just one? * MP4 (mp4, m4a, m4v, f4v, f4a, m4b, m4r, f4b, mov) * 3GP (3gp, 3gp2, 3g2, 3gpp, 3gpp2) * OGG (ogg, oga, ogv, ogx) * WMV (wmv, wma, asf\*) * WEBM (webm) * FLV (flv) * AVI\* * QuickTime | Technology | explainlikeimfive | {
"a_id": [
"eks7s8g",
"eks7v05",
"eksf9sd",
"eksd94x",
"eks9heb",
"ektc18y"
],
"text": [
"[relevant xkcd]( URL_0 ). Everyone format is trying to be the universal format, but each format is gonna have its on intricacy that some people find incredible useful and others find insufferable. The end result is that as long as competing formats exists someone, somewhere, is gonna demand that all work be done in that format.",
"Formats have different intended distribution and quality/size ratios and compression. Example: Mpeg2 is a DVD format that's rarely used these days. AVI is on it's way out. Additionally, formats like some quicktime, Mkv, uncompressed, AppleProRes444 are used as 'lossless' to be exported to another portion of production without any degradation of the footage and are rarely used for consumer level (though some folks insist on lossless formats because of the quality and the fact size restraints are less of an issue these days.) Edit: changed flv to mkv.",
"Video is more complicated than it would seem. Most (if not all) of what you listed are containers, which is different than codecs. Some of the responses here deal more with a codec than a container. One reason I would add is DRM and companies wanting control of their format/devices. Another reason is some containers offer options that other ones do not. There is a [Wikipedia chart]( URL_0 ) what each one supports. Menus are something that a lot of containers do not support for example.",
"Why can't we have one universal car? Different formats and codecs all have pros and cons. Some are simpler while others offer more advanced features. Some make trade offs which make them more suitable for streaming (error correction) while others might be more efficient (higher quality) but aren't very suitable for streaming. One of the biggest considerations is of course the evolution of formats and codecs. In order to get a lot of video quality in a small number of bytes you'll need to do a lot of computations. Modern codecs can offer higher quality with fewer bytes because they include computationally intensive algorithms which simply couldn't be used in the past, while other algorithms simply had not been invented yet. We can't have a universal format or codec for video until we invent something that can't be improved. And even then, videos encoded in older formats and codecs often won't get converted to newer ones both because of laziness and because it's impossible to improve the quality (only make it more efficient) but you will probably lose just a little bit of quality.",
"You are mixing several things, and you have QuickTime twice (.mov is QuickTime, which was used as the basis for the MP4 container format), but the short answer is that there is a lot of effort being put into improving video encoding, because customers want higher quality and bandwidth isn’t growing fast enough to support that. This means making breaking changes, ie new formats. Some people will stay on older formats for various reasons, so you have several generations of formats being active at the same time.",
"There's a bunch of reasons! **Building it to solve different problems:** Do you want to make the smallest files possible? Do you want it to be as simple as possible to decode the file into a series of images on the screen? Do you want it to use as little memory as possible to decode the file? Do you want to make it more resistant to errors? Do you want to include a *ton* of detail in your images? Do you want to lock down the video stream against making unauthorized copies? Do you want to make it super easy to skip around in the file instead of viewing it from start to finish? Building a format that's good for one of these things is generally going to involve making it crappier for other things. **History:** People have been trying to cram video into computers for about thirty years. Even if your phone is a cheap old phone it has a lot more resources than a late eighties computer; old video formats were designed to fit those limits. FLV, for instance, filled a sweet spot in terms of how big its files were versus the Internet speed of its time (and also in terms of how permissive its license it was) and ended up being part of what made YouTube come together. **Financial/licensing:** Figuring out how to efficiently compress video is a hard task. People who come up with compression methods often want to get paid for their work, so they will say \"you have to pay me money to use this format\". So other people who don't want to pay that money will come up with their own format - maybe they'll want people to pay to use their format too, maybe they'll want to give it away like Ogg."
],
"score": [
77,
14,
12,
6,
4,
4
],
"text_urls": [
[
"https://xkcd.com/927/"
],
[],
[
"https://en.wikipedia.org/wiki/Comparison_of_video_container_formats"
],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bcpwou | When a computer is having Domain Name Service (DNS) issues, why can't Windows troubleshooter find a solution? | and why is it that a simple restart (temporarily) solves the inability to connect instantly when no other solution (even a networking reset and a system restore) does anything? relevant edit: this is windows 10, the worst OS ever. | Technology | explainlikeimfive | {
"a_id": [
"eksj1o8",
"eksju2y",
"eksmrum"
],
"text": [
"Usually if there is an issue with accessing the DNS, you don't have a stable uplink to the internet. DNS is the first part of going to a website, so is the part that will have issues first if you can't properly access the internet. I don't know much about Windows troubleshooter, but it's often an issue with your router and/or ISP. It's also possible the DNS you use is down, but that's pretty rare.",
"Windows 10 the worst? I think Windows ME would like to meet you.",
"The windows troubleshooter is doing an ip release and renew. Your issue is DNS, which would be directly related to your provider or your router. A restart fixes it because that essentially is toggling your entire connection at a deeper level. If you want a better fix, set your DNS to 8.8.8.8. Also, learn how computers work before you determine that an operating system is bad."
],
"score": [
6,
5,
5
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bcqdl4 | How is the protocol UDP useful in gaming. | I know it doesn’t check for missing packets, but how does that show in gaming (e.g. less lag...if so, how?) | Technology | explainlikeimfive | {
"a_id": [
"ekso4f8"
],
"text": [
"TCP requires a back and forth conversation between a server and a client. If the client says they didn't get a packet it will ask for it again. And again. The server will try to send it whatever packets it needs. This can be really chatty but it does ensure both sides have the right packets. UDP protocol doesn't care if the other side got the packets. All that back and forth discussion, that TCP has, is overhead and can cause latency. UDP just sends new packets and anything that got lost is lost. For games (live broadcasts and other things) UDP is used frequently. In a game you don't necessarily want your computer doing that intensive \"hey I sent you something. I didn't get it resend it. Okay I sent it again did you get it. Yes!\" conversation for each packet. You just want the next one since the game is continuing. You'll see it in games where a player just teleports across the map. You lost those packets and your system just grabbed the next ones and put the character where it needed to go. You only care about what's happening right now on a game server. Same thing with live broadcasts. You may see it get garbled when you lose connection/packets but when you get it back you are still live. You don't waste time trying to recover those lost packets because those happened in the past."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bcsojm | What is the difference between a lab grown diamond and a cubic zirconia? | Technology | explainlikeimfive | {
"a_id": [
"ekt3vqg",
"ekt4j9c"
],
"text": [
"One is a diamond and one isn’t. CZs are not made of carbon but made from zirconium dioxide.",
"the question should be \"what is the difference between lab grown diamonds and natural diamonds?\""
],
"score": [
9,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bctcmb | While programming a game, how do image textures like this work to make an actual game? | Example: Yoshi Texture from Super Mario Bros: [ URL_0 ]( URL_0 ) Another Example: Chess Game Board and Pieces: [ URL_1 ]( URL_1 ) I don't know much about programming or game development yet, but am curious to know how an image like that can be used to make a fully functional game, rather than individual pictures for each game piece. | Technology | explainlikeimfive | {
"a_id": [
"ekta5p9",
"ektc2z2"
],
"text": [
"When mapping textures to the 3D model you can specify which parts of the texture go on what part of the model. You are basically telling the game engine to only use a small portion of the image for the legs, this portion for the arms, this one for the face, etc. This is more efficient than splitting it up into multiple files. You can also reuse the same texture for multiple different objects like in your chess example. This way only one image is loaded into memory and each game piece is told to use different specific parts of that one texture.",
"In the second image they have stored all the images needed in a single file. They know the dimension and location of each element so it's trivial to get the needed textures from it. There's overhead when opening files that might be perceived by the plaher, so they just put all the graphics in one file and load the entire thing into memory. They can do this because modern computers have plenty of memory. The first one is a bit different. It's packed a certain way due to the way the console it's from loads and displays graphics. On older systems there was very little memory, so they would only allow blocks of sprites to be loaded and those blocks had color limitations. A clever artist or programmer could get \"impposible\" compression or color depth by packing their image data in a certain way. This video from the lead developer on Sonic 3D Blast shows how they packed Sonic's sprites using some clever image packing and hardware mirroring. URL_1 Modern games do use interesting packing techniques. IdTech 6 uses a texture system called virtual textures. Rather than a large number of individual textures, everything in a level is in one giant multi-gigabyte texture. It's not possible to load the entire texture into memory, and there's also bandwidth limitations to consider, so they use an algorithm to pack the texture data in the most efficient way possible. This page explains how DOOM renders a frame, including how the texture is packed. URL_0"
],
"score": [
12,
6
],
"text_urls": [
[],
[
"http://www.adriancourreges.com/blog/2016/09/09/doom-2016-graphics-study/",
"https://youtu.be/YV9x1KY_XWI"
]
]
} | [
"url"
] | [
"url"
] |
bcw5rm | Why did it take so much data to record the image of the M87 black hole? | Technology | explainlikeimfive | {
"a_id": [
"eku3evf",
"ektyi2d",
"ekuftox",
"ektzwdq",
"ekv48l9"
],
"text": [
"Think of it as combining and stitching thousands of large high quality pictures. This would take up a lot of space. Plus they were looking for something relatively small compared to the large amount of space. Those pictures are from big cameras with lots of data in each photo, many gigabytes for all the images collected.",
"Mostly because it was so far away they couldn't use one telescope, so they couldn't use one telescope and set it to make a picture, they had to record the raw data in multiple telescopes and then combine it. And second, black holes are well black, so they were not looking for light from the black hole, but light from things nearby that were affected. Combining data from multiple telescopes requires extra data than you normally need to make a picture as you need to search for things that match from multiple telescopes and compensate, specifically they need accurate phase information, not just time and amplitude.",
"Katie Bouman's Ted talk from a couple of years does a good job of explaining why getting the image was so difficult, which in turn kind of hints at why it took 5 petabytes of data. URL_0",
"The resolution of a normal telescope is WAY too poor to see a black hole in the center of a galaxy. And the resolution of a telescope is limited by the size of a telescope - bigger telescopes give you better images (obviously, right?). So, in order to see a black hole, we basically needed to use a telescope the size of the Earth itself. So we did this by having several telescope all over the Earth looking at the same thing at the same time. Not only are they looking at the same thing at the same time, but as the Earth spins, they fill in even more data. They also take data over time, so they can analyze the difference in time between light arriving at one location and another. So we don't have one telescope, there are 8 of them. And they're not looking at still images, they're taking data as time goes on (movies). Oh, and one last thing - you can't compress these images or these movies like you would with a normal photo, because this compression loses some information (which might be not noticeable to the naked eye, but WILL make a difference when you combine images to analyze them). So basically you have multiple high definition images with zero compression and recording over time... not just a single snapshot like you would take with your phone.",
"Very simplified explanation: That \\~5 petabytes is mostly noise. If you take a picture, there is some \"noise\" in the picture - you may see this if you look really close at a picture it looks grainy and/or blurry. If you take a picture of something when it is dark, or when the object is small, or when the object is far away, then there is more noise, because these make the camera's job harder. Also if there is other stray light around (e.g. a police car with their flashing lights on) that also interferes with the picture. If you get too much noise in the picture you won't be able to see anything. If you take a picture of a black hole that is very very far away and very feint and appears very small, something that is right on the limits of current human technology, then there will be a \\*lot\\* of noise. Also this is radiotelescope picture, so there are a bunch of other radio signals that interfere with the instruments causing more noise. In order to get enough of a signal that they could separate it from the noise, they had to use several \"cameras\" spread around the Earth. After capturing all this, they then did a lot of fancy computer filtering to remove most of the noise, leaving the picture you saw. Managing to extract a useful signal from the data they had is an impressive accomplishment."
],
"score": [
121,
117,
16,
14,
6
],
"text_urls": [
[],
[],
[
"https://www.youtube.com/watch?v=P7n2rYt9wfU"
],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bcwbw0 | How do live broadcast numbers, like poker pots, update so quickly? | So I've been watching a little bit of poker, and the bets, pots, and percentages and poker generally update within 1-2 seconds of the event happening. How is this being updated so quickly? | Technology | explainlikeimfive | {
"a_id": [
"ektz7hc"
],
"text": [
"Most \"Live\" broadcasts of sports still operate with a few seconds of delay. The delay allows on-screen information to update such as drawing the yard line in American football, highlighting the puck in hockey, or updating a player's cards in poker. It also allows the producers to string together the camera shots that are interesting. Lastly, it gives a bit of time to censor swearing or wardrobe malfunctions."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bcxeqa | How does Spotify know when i'm driving (car mode auto enabled), versus when i'm just a passenger in a car (no car mode). | Technology | explainlikeimfive | {
"a_id": [
"ekuannt",
"ekuibf0",
"ekugl5e",
"ekuc464",
"ekuhw9l"
],
"text": [
"If you're using Bluetooth then that could be a way it knows. iPhones know to turn on DND while driving when you connect to a car stereo. I'd imagine it's similar to that",
"It's based on your Bluetooth. You can turn it on/off in the settings, and it explicitly states, \"Allow car view to automatically turn on when Spotify connects to your car's bluetooth.\" So if you were a passenger, and you connected it to the Bluetooth of the car you were in, car view would come on.",
"Root (insurance company) also claims that their app can determine when you’re driving versus when you’re a passenger, because your phone moves differently when you’re a passenger. I assume that to mean either the phone is used a lot more often or that the application is using the phone sensors to detect any small movement that syncs up when, say, you turn the steering wheel or hit the brakes (which could be picked up if it’s in your pocket, in theory). If it detects a quick movement due to your leg moving and then the car slows down, it could pretty accurately guess you’re the one controlling it. I’ve got no idea if this is legitimately happening though. Mostly posting because I’m curious if anyone here knows what’s really going on as well.",
"At a guess, a combination of connected to the car Bluetooth, accelerometer data (the phone is moving, but not in a person-powered way) and lack of interaction with the screen.",
"Even if I'm the passenger my phone goes into car mode when I'm in my car so I don't really know."
],
"score": [
165,
55,
52,
18,
4
],
"text_urls": [
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bcybqc | How do internet speed tests actually work? I think I understand ping, but how is bandwidth measured? | In my mind, a server just tries to send as much data as possible and whatever gets through per second is your download speed, but that seems too simple and also somewhat impractical. Edit: So, I'm a pretty technically inclined person, and maybe I should've explained that. I know what ping and bandwidth are. What I don't know is, when you go to a speed test website ( URL_0 , URL_1 , etc), what are those sites actually doing to measure your download and upload speeds? How do they generate the numbers they give you? Is the visual representation that seems to go up and down during the test an actual real-time representation of what's happening? | Technology | explainlikeimfive | {
"a_id": [
"ekufa6o",
"ekuix4s"
],
"text": [
"Ping is the time it takes to send a message from you to a server somewhere. The time it takes to send a message. Bandwidth is how much data can be transmitted per second. So you can send 1 message in just 1 second to a server. Bandwidth is *how many* messages you can send at once, basically, or *how large* can those messages be is another way of thinking about it. In reality, even large files get broken up into many smaller messages, so really bandwidth is how many messages you can send per second. Ping being how long it takes those messages to get where they are going.",
"basically the idea is that the speedtest servers theoretically have much higher bandwidth than your connection, making your pipe the bottleneck. they then send a large file to you and time how quickly you recieve it. & #x200B; I believe that the realtime numbers are fairly accurate. the way tcp/ip works large files are broken down into smaller chunks(packets) of data and then transmitted. every time you recieve a packet your computer sends a verification that the packet was recieved. So what the speed test is doing is counting the number of packet recieved messages you are sending over a set period of time, multiplying that by the size of a packet, and giving you your speed as Mbps."
],
"score": [
5,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bcyhes | Why do videos freeze up when entering and exiting full-screen mode? | I've noticed that videos tend to freeze up for a second or two when entering or exiting full-screen mode. This has happened on every computer I've used for as long as I can remember. Why does this happen? | Technology | explainlikeimfive | {
"a_id": [
"ekuj0s6"
],
"text": [
"Some video players will attempt to raise or lower the resolution of the video if you enter or exit full screen mode, which can cause the video to freeze while the different resolution footage is requested from the server. On a really slow machine the process of switching in and out of split screen can also be taxing by itself. This is especially true for machines that don't have graphics cards, since the processing power is being shared between the video player, and the rest of the computer. It could also just be a bug in the video player. Playing videos is a pretty complicated problem in computer programing, and writing huge programs without bugs is pretty hard."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bcyhjs | How do electric vehicles cut down on carbon emissions? I know they don't use gas but don't we still have to burn coal etc to power them up? | Technology | explainlikeimfive | {
"a_id": [
"ekuh3qs",
"ekunzeq"
],
"text": [
"Power from power plants is often times much more efficient. It’s like how BNSF advertised that, by scale, a train gets roughly 340mpg compared to other shipping methods like trucks. Also, power comes from multiple sources including clean sources like hydro, wind, solar, nuclear, etc. Tesla’s Gigafactory is also powered by renewables. The idea is that overtime, as renewables take over, the carbon footprint of electric cars will fall even further.",
"EVs are able to cut down on carbon emissions because they are far more efficient at utilizing energy - while the average gasoline-powered car [has a tank-to-wheels efficiency of 17-21%, electric cars have a grid-to-wheels efficiency of 59-62%]( URL_0 ). The practical upshot of this is that even if you account for the contribution of coal and other fossil fuels to the grid, [99% of the US' population]( URL_1 ) live in places where driving an efficient EV will yield lower per-mile emissions than even a Prius. In Europe, EVs [also realize significantly lower lifecycle emissions than diesels]( URL_2 )."
],
"score": [
22,
13
],
"text_urls": [
[],
[
"https://www.fueleconomy.gov/feg/evtech.shtml",
"https://blog.ucsusa.org/dave-reichmuth/new-data-show-electric-vehicles-continue-to-get-cleaner",
"https://www.transportenvironment.org/press/electric-cars-emit-less-co2-over-their-lifetime-diesels-even-when-powered-dirtiest-electricity"
]
]
} | [
"url"
] | [
"url"
] |
|
bd18m6 | How do 3D printers work? | Technology | explainlikeimfive | {
"a_id": [
"ekv1mvg"
],
"text": [
"There are two different main kinds. The first works by building layers of resin set by a UV light source, from a screen that can be blacked out to create the shape of the layer. So you have a screen submerged inside a bath of liquid resin plastic, and the image you are creating is formed on a stage that is dropped into the bath to leave a small space between it and the screen, shone with UV to solidify a thin layer in the shape you want, lifted out to harden, then submerged again to build up a second layer. The shape is built upside down on the stage. UV stands for Ultraviolet, which somehow sets/cures the resin, and is a small element of sunlight that creates sunburns but can be made from bulbs and special lights- like sunbeds. The second is a tiny needle depositing a small blob of solid plastic that is then melted/welded into the rest of the solid object to build up the 3D image."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bd4ymo | How does gps work? | Technology | explainlikeimfive | {
"a_id": [
"ekvshez",
"ekvs92k"
],
"text": [
"The GPS system is composed of 31 satillites orbiting the earth. Their orbits are arranged in such a way that no matter where you are you should always \"see\" at least 4 at once. Those satillites are constantly sending out radio signals telling you the current time and their exact location. A GPS listener (for instance your phone) is listening for those signals. So, your phone is constantly listening, and will pick up a message that says the equivalent of \"Hi! I am GPS Satillite number 15. The current time is 12:54:22 UTC. I am currently at this location in my orbit, at this altitude\". Your phone hears that and can use that information to calculate how far from satillite 15 it is (it knows when the satillite sent out the message, and it knows how fast the message travels, and it knows where the satillite was, so from that it can deduce how far away it is). This on it's own isn't enough, because that means the phone could be in multiple places on the eartht that happen to be exactly that far away from SAT15. So, to narrow it down your phone will listen for signals from other satillites and collects more data. SAT09 says it is this far away, SAT23 this far, and SAT03 this far. Using the information from all four satillites your phone now can pinpoint where on earth you are. How can more information help? Well, consider [this image]( URL_0 ). The points represent the satillites and the circles the distance away from the satillite you currently are. If you only have one satillite you know you're somewhere on the circle, but now where. By also knowing where the other satillites are you can find out where all the circles intersect. You're positioned where all three circles meet, near (6,3)",
"The satellites transmit a time signal, and details of their orbits so that you can work out where they were when the signal was sent. By comparing the time signals you're receiving from two satellites, you can work out that the signal from satellite A is taking a little bit longer to reach you than the signal from satellite B. Since you know that the signals all travel at the speed of light, this tells you how much further away satellite A is than satellite B. Repeating this for more satellites (preferably at least four), you can calculate that there's only one place where all the differences in distances to the satellites are true, so that's where you must be."
],
"score": [
10,
3
],
"text_urls": [
[
"https://i.imgur.com/O1r3T4D.png"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
bd7lhx | Is there a way to make an electric jet? | Technology | explainlikeimfive | {
"a_id": [
"ekwbgcy",
"ekwa91r"
],
"text": [
"Sorta. For most air-breathing propulsion, the idea is to compress air, add energy to it when it's compressed, and then allow it to expand and push you with thrust (for turbines) or push a piston (for piston-cylinder engines). The reason you add energy when the air is compressed is due to the way heat engines are constrained by thermodynamic laws, but the short version is that you want to make the difference between the compressed and expanded (i.e. atmospheric) states as big as possible, in terms of both pressure and temperature (although these are linked closely enough that, you can *kind of* consider them to be the same thing). The larger the differences between the \"hot\" and \"cold\" sides of the reaction, the more efficient your process will be. Normally, that added energy is by combustion of fuels, but with an electric jet you can (on paper, at least) use an electric current to heat the air directly and then allow it to expand like normal. The problem is that this is kind of difficult to do, and as a result it's not really that efficient because you can't generate that much heat, thus it won't be very efficient. The more efficient method is to just use the electrical energy to power a large fan to push you through the air.",
"Also it gets complicated because of pressure difference when higher up in the atmosphere, hence the reason why it is generally unacceptable to bring lithium ion batteries on board a plan (non carry one)."
],
"score": [
9,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bd944a | How do HBO's servers work for Game of Thrones? | Technology | explainlikeimfive | {
"a_id": [
"ekwkcug"
],
"text": [
"One of the ways is by having a big distributed network of servers spread out geographically. Each of these servers has its own copy of the content and can send it to clients (viewers) in its area."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bdaj1n | How do they take videos of food cooking in ovens? Is there a specific type of camera used to do so? | Technology | explainlikeimfive | {
"a_id": [
"ekwx1x4"
],
"text": [
"Whirlpool and Electrolux both sell home oven's with built in web cameras so you can remotely watch your food cook. Other companies make commercial cameras and camera housings to allow you to put cameras into kilns and industrial furnaces which run far hotter than an oven. A recent thread on a video sub had a number of suggestions the simplest being just film through a door window and adjust the colours in post production. URL_0"
],
"score": [
8
],
"text_urls": [
[
"https://np.reddit.com/r/videography/comments/a94uod/video_camera_for_use_in_an_oven/"
]
]
} | [
"url"
] | [
"url"
] |
|
bdbax4 | how do graphics cards actually give a computer so much processing power over the CPU? | Technology | explainlikeimfive | {
"a_id": [
"ekx0pdc",
"ekx85b8",
"ekx9syf",
"ekx1227"
],
"text": [
"CPUs are generalists. They have components designed to tackle all sorts of tasks making them the good at all tasks but masters of none. GPUs on the other hand are specialists. They contain a huge number of cores but they are designed for specific arithmetic functions related to graphics. By design that makes these cores good for processing certain types of mathematical equations like hashes. You can't really run your computer on a GPU, but leveraging a GPU can be useful in processing certain types of tasks since it's much more efficient at those tasks than your CPU.",
"Since this is ELI5, the CPU is like a really smart fuckin guy who's better than everyone, but he's just one guy(or a few guys when it's multi-core CPU, like quadcore/6-core/etc.) The GPU is more like a couple thousand run of the mill, average folk. Like when you're playing a game, the few fucking smart guys(CPU) calculate/run the code while the thousands of average folk(GPU) frantically paint pixels or do a bunch of basic bitch calculations that the CPU guys want figured out but hey, they're only a few guys and have better shit to do.",
"CPU = Albert Einstein. One and only, smart, but just himself. GPU = Reddit users. Many in number, but not-so-bright as Einstein. \\------ Task #1: Make ONE beautiful, high quality, original post on reddit. Result: Einstein outsmarts all and gets lots of karma for this ONE post. Einstein wins. \\------ Task #2: Shitposting memes as much as possible to flood reddit. Result: The massive amount of mediocre Redditors are able to product lots of shit posts, because each post is a trivial task that requires low effort. Einstein, despite being smart and stuff, is simple unable to match the massive PARALLEL power of the teeming masses. Redditors win. \\------ The task #1 is a complex task that computers needs to solve in sequence and fast, so CPU Einstein works the best. The task #2 is a large task composed of massive amount of simple tasks in parallel, so GPU redditors work the best.",
"Graphics cards don't actually have \"more\" processing power so much as having \"different\" processing power. Graphics cards are optimized to take in huge quantities of data and perform a small set of relatively simple operations on them, then output them very quickly for display. A CPU on the other hand is designed to be very flexible and to perform a long chain of potentially complex operations on the same set of data. So you see they are designed to do very different kinds of tasks; a graphics card simply couldn't do what a CPU does, but similarly a CPU can't keep up with a graphics card when it is doing what it is designed to do. An analogy would be a factory with 10,000 assembly lines with three fixed stations each (graphics card) or a factory with 500 assembly lines each with 50 possible stations that can be swapped out for anything (CPU)."
],
"score": [
26,
24,
10,
7
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bdckit | 5G mobile networks and why they are considered such a big deal | Technology | explainlikeimfive | {
"a_id": [
"ekxbffz",
"ekxbg2x"
],
"text": [
"It's the next step in mobile network data transmission. There's new stories causing a big deal about it but it's the same as if Apple was releasing a new iOS or if Microsoft was releasing a new version of Windows. 5G is just going to be faster. Some experts say could be 20 times faster then 4g. Bonus fact: the \"g\" stance for generation. 3-g network was released in 2001and 4 g was released in URL_0 that could be another reason why people are making a big deal out of it it's the next jump forward in technology that we haven't seen in 10 years. Also this technology isn't just for mobile phones it's going to be coming to Wi-Fi routers in the future and with 5G technology gigabit-per-second internet is going to become a regular everyday thing for a lot of people one drawback experts are saying about 5G technology is that the signal will degrade faster then 4g. Which means just going to need to be a lot more cell phone towers. Some experts say cell phone towers will need to be 500 meters apart",
"apart from crazy fast upload and download speeds, they give very little latency or delay when you do things that require it. Some examples are gaming on phones and video calling. Gaming on phones will have very little latency or lag and gives an overall better experience. Video calling is good but now you can video call with higher quality with no reduction in actual call quality and use your cameras full potential when we're video calling instead of the image being compressed and becoming much lower quality on the receiving end."
],
"score": [
9,
8
],
"text_urls": [
[
"2009.so"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
bdf8cx | Difference between Phishing and Social Engineering | Thanks! | Technology | explainlikeimfive | {
"a_id": [
"ekxom3d",
"ekxodzr"
],
"text": [
"Phishing is a subset of social engineering. Social engineering is any kind of attack where you trick people into doing something that isn't in their best interest or what they thought they were doing, rather than defeating technical prevention measures. Phishing is presenting someone with a legitimate-looking request for information, like a website that looks like a familiar login screen, and hoping they provide some kind of sensitive information.",
"Phishing is creating a replica of a website, mail service, social network or anything that looks just like the original and has similar domain, like facebo0k or instagran, so people enter their account details because of negligence. Social engineering is retrieving information from a person by any means possible. Remember banks or steam that sends you a message \"Never tell this code to anyone\". If you find yourself in the situation where you willingly gave out information to the third party, you've been social engineered."
],
"score": [
8,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bdgaov | how torrent sites such as PirateBay manage to not get shut down? | Technology | explainlikeimfive | {
"a_id": [
"ekxwv4t"
],
"text": [
"A lot of torrent sites try to hide behind the whole \"We don't create the files and don't censor our users\", this works to varying degrees depending on the country they are hosting the server in. Something like PirateBay as a server doesn't explicitly create and share copyrighted works, they instead host a service that allows users to share copyrighted works. It's a legal grey area that doesn't hold up well in many countries which is why it gets shut down often, but hiding in those grey areas is also how it keeps getting put back up. EDIT: Another distinction is they don't actually host copyrighted works at all, they only host torrent files that allow users to connect to each other to obtain copyrighted works. The content itself that they host is not copyrighted (torrent files don't actually contain copyrighted stuff, they only point users to other users who have copyrighted stuff available for download)."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bdgvef | If almost every large animal with mobility has forward bending knees, why do so many advanced Boston dynamics type robots have rear facing knees? | Just wondering. It would seem the only natural application to (seemingly, but are actually there ankles ie flamingos) rear bending knees are things like birds that always crouch forward. Most all the 4 legged Boston dynamic robots bend there joint backwards, and they seemed to have JUST got decent two legged ones that walk anatomically similar to humans. Why don’t they just imitate the nature that works? Thanks. Edit: I wanna thank everybody. And for everyone that maybe didn’t understand how I worded the sentence but I tried saying between the parenthesis that I know the rear bending knee most of the time is just seemingly so, I’m aware that those are actually ‘ankles’. Also.. my main question was about the humanoids they make. They just got the point of having that two legged one walk ‘normal’ and jump up stairs, flip, etc and I was wondering why they didn’t do it anatomically from the beginning. Anyone who hasn’t seen those search all the Boston dynamic vids there cool. Thanks again guys. | Technology | explainlikeimfive | {
"a_id": [
"eky3yk6",
"eky3eh0",
"ekypjvg",
"eky3lrf",
"ekyszi4",
"ekyy6xe",
"ekytnxk",
"ekyv2xc",
"ekzjacp",
"eky4fxy",
"ekz2hzg"
],
"text": [
"The answer is: [because it's more efficient]( URL_0 )! In the simplest sense: figures 21 and 22 in the linked study show that if you eliminate hip movement, the backward bending leg can still make progression towards the following step. The forward bending leg can't. So the forward bending leg will always require more hip movement than the backward bending leg. The data in the experiments indeed show that the hip movement is much less important in backward bending legs than forward bending legs. Also, there is a slight advantage in shock damping. EDIT: Sorry, forgot I was on the university network at the time of writing, so you probably won't be able to see the full article (the main idea is explained in the abstract). Will try to provide some more information tomorrow. EDIT2: Fixed link (thanks u/quote_engine) : Interpretation of the results starting p10 is where it's most interesting.",
"Actually, it's not true that 4 legged animals all have \"forward bending\" legs. They do but they also don't. So, what animal can climb, run and walk well? We probably want these on our robot, right? Maybe a goat?: URL_0 Maybe a cat?: URL_1 Notice how their legs also bends backwards, not on the \"knee\" yes, but they're not only forward bending either. Funny note, even us humans have \"back bending legs\", which is our feet and ankles, the only difference is after they bend back they also touch to the ground: our heels. So, since they're robots, it's to be expected to not have the exact same structure as an animal (no need to exactly design a \"feet\" if a round surface can do the same job) but if you compare the skeletons and have an \"overall\" look, they're quite similar to many animals. Hope it helped.",
"Tangential but important: evolution doesn't necessarily select for *best*. Simply *good enough*. The only time that *best* or even *better* traits will evolve, is when there is direct competition. If, hypothetically, 2 species existed: one with forward knees, one with rear-facing knees, and if these two species has similar diet, in the same area, or were in competition for breeding grounds ... some form of competition .. then the best feature would likely win the day, and evolution would trend that way. But as far as I know, that never happened. The knees we have evolved first, they were good enough to move their owners around to get food and reproduce, so they stuck. Evolution is a bit of a crapshoot like that.",
"It all comes down to how you define what a \"knee\" is, there's at least three ways based on human anatomy: * The joint in the middle of the leg * The first joint after the hip (the second joint from the top) * The first joint after the ankle (the second joint from the bottom, *if* we ignore all the joints in the foot). Most robots that have backwards bending \"knees\" only have two joints. From the perspective of how their feet interact with the ground, that joint is much more like an ankle, it controls the angle of the foot hitting the ground. And in that sense it works just like our ankle, and bends \"backwards\" for the same reason our ankles bend that way. When you walk forwards, it's useful to be able to push off with your foot, so you want the joint behind the foot, which pushes forwards when the joint opens. Boston Dynamic's humanoid robot has feet with joints, and it has forward facing knees and \"backwards\" (i.e. normal to us) facing ankles that do this job and let it [push off with each step]( URL_0 ). This is also the reason why flamingos look like they have [backwards bending knees]( URL_1 ). They're really standing on their \"tip toes\", and the joint we see is their ankle. Imagine you wanted to make a robot flamingo, you might simplify it by deleting the top of their leg ([which is way up beside their body]( URL_3 )) and make the first joint the \"knee\". In a lot of ways knees and ankles are interchangeable, their orientation just depends on what's happening below them. And actually, if people need to have their lower leg amputated, in some case they can replace their knee joint with their ankle by turning it around and reattaching it. And it works [amazing well]( URL_2 ).",
"As a character artist who understands anatomy and frustratingly listens to coworkers (who should know better) describe this as backwards legs or backwards knees... There is simply no such thing. Every land mammal has a hip, knee, and ankle and they all bend in the same general direction. The joint that you describe is actually an ankle joint with an elongated foot; typical of most mammals that walk on all fours. This elongated foot allows for less stress on the hip joints and for better overall leg flexibility in an quadrupedal configuration. Animals with greater hand and forelimb dexterity often have shorter feet and use their entire foot/ankle to balance while manipulating things with their hands in a more upright posture. The joint layout remains the same. You can take skeletons from nearly all animals and find they all share the same basic structures (skull, shoulders, elbows, wrist, hips, knees, ankles) in different proportions. Its extremely interesting to explore. Even modern whales have vestigial leg bones from previous evolutions. In regards to the robots, there really isn't a comparison. Neither layout matches an animal's skeletal system. Robots aren't restricted to the same bio-mechanical limitations of animals with bones and muscles. I'm certainly no engineer, but I'd imagine their design reflects whatever is most efficient, stable, and easiest to program. & #x200B; EDIT: Thank you for the silver, friend!",
"Evolution isn't engineering. The robot is designed to be more efficient. Evolution is just a lucky mess of happenstance.",
"Knees are funny. What on most animals appear to be knees are actually ankles if you look at the skeleton rather than the fleshy bits. Which tells you two things. One, humans are built kinda funny, and two, having a joint bending that way in that area is way more efficient, especially when it is easier to control with an opposing joint above it, which is the true knee.",
"Oh boy Are you sure you're not confusing \"backwards knees\" with digitigrades?",
"I work for Boston dynamics. Although I cant really talk about how the robots were designed I'd like to point out: Big dog: both knees and ankles. Knees fwd, ankles backward. Wildcat, cheetah and ls3: only ankles, mirrored front to back. Spot: only ankles, both sets facing backward. Petman, atlas: human morphology knees and ankles. So of those robots only spot, ls3, wildcat and cheetah have had \"backwards\" legs from a human perspective.",
"I can't really give a full answer coz I don't know their technical limitations, but something to consider is knee structure being forward facing has more to do with impact cushioning and the conservative nature of evolution than any inherent stability. Many of their early robots forgo the inclusion of wrist or ankle joints, which gives them the backwards knees, but structurally they're working like a digitigrade or forelegs of an animal. This is simple and stable when using servomotors. I'd recommend looking at the forelegs of some four legged skeletons and compare for yourself how these line up with some of BDs work.",
"i may be wrong and i'm not that much expert, but the birds' ones aren't knees, but ankles as you said. This tho is the key to all the answer. The part under the articulation is the foot which ends with fingers that actually touch ground. The knee is hidden under feathers and points forward. Imagine if your foot becomes long and you walk on the points of it, only using your digits. That is how birds are, they have a knee (pointing forward) and an ankle (pointing backward). May take a look at an ostritch. Also take a look at an horse. They have the same structure divided in 3 parts as an ostritch, but look how in the front legs the knee points backward and the ankle forward"
],
"score": [
6247,
677,
308,
140,
42,
31,
20,
14,
9,
4,
3
],
"text_urls": [
[
"https://sci-hub.tw/10.1088/1748-3190/10/1/016011"
],
[
"https://commons.wikimedia.org/wiki/File:Goat_skeleton.jpg",
"https://www.amazon.com/Crazy-Bonez-Z18071-Skeleton-Cat/dp/B00M94FHTO"
],
[],
[
"https://www.youtube.com/watch?v=LikxFZZO2sk",
"https://www.aviary.org/animals/American-Flamingo",
"https://www.youtube.com/watch?v=QQVAHbAV8QM",
"https://images.theconversation.com/files/170615/original/file-20170523-5763-k87ko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"
],
[],
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
bdioza | How do producers of movies and TV shows make lighting people on fire seem so realistic? | Technology | explainlikeimfive | {
"a_id": [
"ekye09w"
],
"text": [
"A lot of the time when they need a flaming person to stumble out of a burning area they actually just set someone on fire. They are stuntmen of course, wearing protective fireproof suits and slathered in gel that will evaporate rather then letting their flesh burn. But they are actually on fire."
],
"score": [
14
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bdlst1 | Photo-realistic animation: How and Why? | Tried this at r/NoStupidQuestions, but I didn't understand the answer, and then I remembered this place. :) So I was watching "Love, Death, and Robots," and I actually had to look up whether the "Lucky 13" episode was animated or not. In fact, if I didn't already know that the whole series was supposed to be animated, I might have assumed it was live action. So how the heck do they get it to be so perfect? And what are the advantages of animating it that way over live-action? | Technology | explainlikeimfive | {
"a_id": [
"ekz4sdp",
"ekz9rd6"
],
"text": [
"So a really cool technology called photogrammetry is being used a lot more often these days in media, where high quality pictures, images, and videos are being taken and the images are then converted to code, which shows up as a 3D model rendering. That's not the answer to your question though. Many talented artists spend their 9 to 5's painstakingly crafting these ultra high quality 3D models of spaceships, people, etc. It took years, and every year it gets a bit better. It's alot like making a painting just in a digital space, except that it ideally moves. The advantages to animation are many. Animation is the most free art form. The only limit to what you can make is in your imagination. The drawback is that series like \"Love, Death, and Robots\" are generally underappreciated by the general viewing public and do not make much money in comparison to how much they cost. So if you liked the show, support the artists! :) (Edited for grammar)",
"3D modeling, rendering, and animation techniques have been steadily improving to the point where you can really get some realistic looking scenes. As stated in other posts, one can now take detailed photos and video of things and make accurate 3D models and animation of them for digital use. However, most studios have stayed away from attempting photo-realistic shows and videos, as if it is a tiny bit off, it triggers the uncanny valley effect in the viewers who end up feeling very uncomfortable with it. To avoid this, most studios purposefully make their world and characters obviously animated as to avoid the uncanny valley dilemma. It sounds like the studio making the show is taking the chance though."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bdmmbx | how do wammy bars (on guitars) work? | Technology | explainlikeimfive | {
"a_id": [
"ekz9eys",
"ekza87r"
],
"text": [
"Basically you use the bar to add extra tension to the strings to shift the pitch as you play.",
"The correct name is a tremolo bridge. When you push on the bar it removes tention from the strings causing lower notes. Some of them (floating tremolo bridge) you can pull on creating more tension, increasing the pitch."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bdswle | How do charging pads for phones, or that new Samsung that can charge from another phone, work? | Technology | explainlikeimfive | {
"a_id": [
"el0gc56",
"el0pa3i",
"el0ohg1",
"el0lnwf",
"el0quvx"
],
"text": [
"It's a form of inductive coupling. The phones have a coil of wire, as does the charging pad. When a high frequency alternating current is passed through the wire coil in the charging pad or phone which is providing charge, a magnetic field is created that switches its orientation very quickly. If the phone to be charged is placed very close to this magnetic field, then a voltage will be induced \"created\" in it's own coil. Add in some fancy rectifying electronics to convert the high frequency induced voltage into a clean and regulated DC voltage, and you've got yourself a wireless charging system!",
"If you put electricity in a wire that’s shaped the right way, it will make a magnet. If you move a wire (that’s also shaped the right way) near a magnet, the wire will make electricity. So if you keep turning electricity in one wire on and off, and you put another wire next to it, the second wire will start moving back and forth. When the second wire starts moving back and forth next to a magnet, electricity comes out. Because the first wire is becoming a magnet, it doesn’t have to be touching the second wire to move it, but when the second wire moves, it makes electricity. The second wire would be in your phone.",
"It's called [Induction Charging]( URL_0 ), ~~often abbreviated as~~ [~~QI~~]( URL_1 ) It works on the same principal as a simple motor/generator, electricity flowing through a wire creates an electro-magnetic field which induces charge in nearby wires. This effect breaks down with the square of the distance between the wires, so you have to keep them very close together, which is why you can charge something by placing it on the charge-pad, but the charge-pad couldn't induce power in something across the room.",
"Basically we create electricity using magnets simply by moving the magnets close to a wire. Electricity running through a wire makes it magnetic. So the wireless charging pads do is run a changing electric current through their wires, creating a changing magnetic field(which simulate a moving magnet), which in turn *inducts* an electric current in the charging receiver.",
"You know how transformer works? One like in the picture [here]( URL_0 ). Two coils on a common core (a thick loop of steel plates). One coil, powered externally, acts as electromagnet generating magnetic field in the core. The other transforms that field back into electricity - either higher voltage, lower current or vice versa, depending on the ratio of number of loops of the coil. Now cut the transformer's core in half, separating the two coils. Bring the halves together. It's still working, the magnetic field flowing through the gap between the halves of the core - with some losses, but still most of it passes fine. Same here. One half of the transformer is in the table, the other is in the phone."
],
"score": [
464,
51,
14,
4,
3
],
"text_urls": [
[],
[],
[
"https://www.makezens.com/wireless-charging-technology/inductive-charging-qi-standard/",
"https://en.wikipedia.org/wiki/Qi_(standard)"
],
[],
[
"http://www.animations.physics.unsw.edu.au/jw/transformers.html"
]
]
} | [
"url"
] | [
"url"
] |
|
bdt1kk | How come when you film a computer or TV screen it appears to have black bars running through it that you never normally see? | Technology | explainlikeimfive | {
"a_id": [
"el0h9gn",
"el0q4p0",
"el0ne5o"
],
"text": [
"Simplest explanation is because of the way old monitors/TVs display their image at a slow frame rate and how the camera is recording at a different frame rate. During playback they’re out of sync so you start to see partial scans on the display. Kinda like how a fast spinning wheel can look like it’s spinning backwards.",
"I would watch this. It is really an amazing explanation. & #x200B; [ URL_0 ]( URL_0 )",
"Like a film, video isn't really moving. The screen is being redrawn 30 times a second, and the picture is showing the screen in the process of redrawing which happens too fast for the eye to see."
],
"score": [
13,
8,
3
],
"text_urls": [
[],
[
"https://www.youtube.com/watch?v=3BJU2drrtCM&t="
],
[]
]
} | [
"url"
] | [
"url"
] |
|
bdu2hf | How do the microphones in over-the-ear headsets isolate the voice so well? (the ones without any external microphone) | Technology | explainlikeimfive | {
"a_id": [
"el0vf10"
],
"text": [
"I mean something like [this]( URL_0 ). Microphone is embedded in the headphones. Just a little pinhole."
],
"score": [
5
],
"text_urls": [
[
"https://i.imgur.com/5Wnpc6R.gif"
]
]
} | [
"url"
] | [
"url"
] |
|
bdufd3 | How do companies that make things such as drone remotes and car keys ensure that the signals won’t work with other drones/cars? | Technology | explainlikeimfive | {
"a_id": [
"el0rrd7",
"el0rf1g",
"el0rroc",
"el2qu9h"
],
"text": [
"Much like a physical key, each remote key system uses a unique code to identify itself. It was not always like this; in the early days of remote keys, a manufacturer would use a limited number of codes, and it was possible for a key to open a car that wasn't yours. Today it's typically taken a step further using what is called \"rolling code.\" Basically, both the key and the car get a copy of the same book, and they each maintain a bookmark. When the key gets pressed, it transmits the first sentence of the page we're on. The car checks its copy of the book, says \"yup, same as what I've got\" and both turn to the next page for next time.",
"Generally, it comes down to having an enormous number of possible codes over a broad range of frequencies. The number of possible code and frequency pairings far far far exceeds the number of devices that operate at those frequencies. It is still of course possible for devices to interfere, so most of them have a way of switching between three or four frequencies or codes.",
"The communications are scrambled against a shared secret; without the secret, the signal can’t be decoded and used. The secret usually boils down to a number that has less probability of being guessed than there are atoms in the universe. Of course, to save money, some companies take shortcuts which mean that monitoring the communications over time, people can guess the secret based on the information they expect to be transmitted.",
"When I had a Saturn years ago, I stumbled across another one that I was able to lock and unlock. I was trying to unlock mine, and got a beep beep and a flash of lights to the car next to mine. I had a lot of fun locking and unlocking it until my aunt got fed up and took away my remote. 🤣"
],
"score": [
37,
12,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bdx90x | the new PlayStation 5 details. Specifically “Ray Tracing” | Technology | explainlikeimfive | {
"a_id": [
"el1ewvi",
"el1ervz"
],
"text": [
"Ray tracing graphics is a different sort of algorithm than the field plane algorithm used in more graphics cards. In field plane, you have high resolution images for things that are near to the point-of-view and lower resolution, smaller things far away. The algorithms compute from the point-of-view out, stopping once they hit something. This effect makes everything matte. Movies use a different algorithm. The ray tracing algorithm takes light from a source to the surface and the from the point-of-view to the surface. When the light touches a surface, it can either be dispersed, like in the field plane algorithm, or it can be reflected. When light reflects off an object, it can hit another object, taking o contribution to color and intensity from that object. Ray tracing will also allow moving light sources to be much more affordably computed. You can do this today, with one player carrying a torch for example, but it shows the \"not-shiny\" attribute of objects in a way that's unattractive. Since ray tracing objects can be shiny, moving light sources are going to look a lot better. Sony's goal is to make games look more like movies, which may or may not make them better games that sell more copies.",
"Think of ray tracing as a passage of a light wave. Light can bounce of some objects, as light can be absorbed by others. In 3d graphics, they've managed to emulate this by tracing the path of an amount of pixels to interact in a real time environment, making textures more life-like by allowing light to interact as it does in nature. & #x200B; The Playstation 5 will have this processed by an AMD Navi processor, that will handle graphics differently from its current processor. So Light will be better reflected off shiny materials, and it will be absorbed by darker materials, just like it does in life. When an explosion happens for example, the light emitted from that explosion will affect every texture rendered around it, including water, metals, bricks, glass interaction, and glossy eyeballs. & #x200B; This is made by mathematically taking a pixel and using a vector to predict its passage as it travels in a realtime environment, making a particle react to it surroundings. If a spark flies through the air, there are objects that it's emitted light will reflect off of, and objects that will hinder its light. & #x200B; Here's a decent article on it: [ URL_0 ]( URL_0 ) Scroll down to the reflections off a car in battlefield V to see it in action."
],
"score": [
5,
3
],
"text_urls": [
[],
[
"https://www.businessinsider.com/sony-playstation-5-what-is-ray-tracing-explained-2019-4"
]
]
} | [
"url"
] | [
"url"
] |
|
bdzymr | How does a theremin work and how does the capacitance work between our hand and the antennas? | Also, how does one antenna control pitch and the other control volume? | Technology | explainlikeimfive | {
"a_id": [
"el24z06"
],
"text": [
"There are two antennas that produce electromagnetic fields. A vertical antenna that is used to control the pitch, and a horizontal antenna to control the amplitude (volume). The theremin uses something called \"heterodyning\". This is when you combine two signals to create a new one. If we look at the vertical antenna, there's one signal that has a constant pitch, and another one that can produce a wide variety. The latter is connected to the vertical antenna, and when you move your hand up and down along this antenna the pitch changes. The same goes for the horizontal antenna, but instead of controlling the pitch it controls the volume of the tone. The closer you put your hand to the antenna, the more quite the tone becomes. When the electromagnetic fields created are disrupted by the human body's natural capacitance it frequency is altered. Unfortunately, I can't explain this in detail without doing some more reading, but basically, when the hand (or any other body part for that matter) disrupts the antennas' fields at a certain point, this creates a certain frequency that is transformed into either a certain tone or volume depending on the antenna."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
be09h6 | Do I use less cellular data directly to my phone, or through a WiFi hotspot, which is using cellular data? | Self-explanatory. Curious. | Technology | explainlikeimfive | {
"a_id": [
"el23i8p"
],
"text": [
"Theoretically, if you are asking if using your phone as a wifi hotspot for a laptop will use more data than using the browser within the phone itself, the anwser would be using the phone itself. Being a phone it will request the mobile version of websites first which are built much liter and easier to run on smaller processors. While you use a laptop via a mobile wifi hotspot you will request the full page, and every little page detail."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
be0tuv | I understand the concept of how ray-tracing works, but what was changed to make it work in real-time on graphics cards? | Technology | explainlikeimfive | {
"a_id": [
"el2e2fr",
"el28os5"
],
"text": [
"New algorithms simplify the computations required. Also, building GPU chips for ray tracing means the hardware is better suited for the specific tasks that ray tracing demands. We've heard for years that real-time ray tracing was decades away from being possible (or perhaps impossible), but that was assuming every single pixel was being ray traced. When you only ray trace a fraction of the pixels and then interpolate the results for nearby pixels, it becomes a lot more doable.",
"I think they use much less rays than a regular ray tracing would and then denoise image with some kind of machine learning based algorithm."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
be1nkg | Why do routers wear out? | I've had computers, smartphones, TVs, electronics in general last for many years. Yet I feel like I've never had a router last more than 2-2.5 years. What about them causes them to invariably die fairly quickly? | Technology | explainlikeimfive | {
"a_id": [
"el2gpf2",
"el2incl"
],
"text": [
"Lots of people store routers in cupboards or have blocked vents where they can't cool down. Mine sits in the open as a feature to stay cool. Thermal damage will happen otherwise. They should last many years",
"TLDR: Low quality parts and heat damage Consumer grade electronics are not built to last, they are built to be cheap to make. They frequently use lower grade electronic parts compared to what we see in business class routers which makes them more susceptible to failure. Most of them are also passively cooled, meaning they don't have fans. While it's true that less moving parts means less that can fail in the short term, it makes these devices more susceptible to heat damage. People tend to be quite abusive to their home electronics. They keep them in closed cabinets, under/behind desks, and never clean them. I've seen tons of home routers with broken wifi antennas because they've been kicked or dropped. Invariable the heatsinks fill up with dust and device overheats. This can cause soldering joints, chips, capacitors, and other electronic parts to fail. Consumer grade routers (Linksys, D-link, Netgear, TPlink, etc) are inferior quality to those made for businesses (Cisco, Sonicwall, Fortinet, etc) which last considerably longer. But there's a reason the later ones cost 10x as much."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
be7avm | why data breaches are still at large given the widespread awareness and information regarding how vulnerable certain areas can be? | Technology | explainlikeimfive | {
"a_id": [
"el3hhml",
"el3hngf"
],
"text": [
"For essentially the same reason that stabbings are still, despite the widespread awareness that a knife in the body is dangerous. It is simply impossible to 100% protect yourself against the possibility that someone else might stab you, and likewise it completely impossible to 100% protect you against somebody reaching your data systems. By definition, a data system is useless unless people can use it, so you have to have some vulnerabilities because those vulnerabilities are the access points that the legitimate users will use.",
"😂 Oh boy... awareness and regular info/warning e-mails. Whole classes with tests to inform people about security. And there is always that one guy, still opening the e-mail. The attachment with the virus. People are dumb if it comes to repeating tasks. Same reason people use phones while driving. \"I’m not so stupid 😤. I can multi task. I will notice a virus e-mail not like person X over there\""
],
"score": [
13,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
be7rg3 | Why do some lightbulbs make white light and others yellow light? | Obviously, some bulbs use tinted glass for red or green, etc, but I can't see a difference in bulbs in my house that produce white 'outside' light and yellow light. | Technology | explainlikeimfive | {
"a_id": [
"el3m2g0",
"el3l44i"
],
"text": [
"Incandescent (filament) bulbs are generally on the warmer side, but the century old tech can't produce actual 'daylight' light which has a temperature color of around 5600 °K. Fluorescent lights tend to be on the cold/blueish side and LEDs, which are fast replacing both Fluo and incandescent tech are available in color temperature ranging from very white/blueish to warm white. A good choice for home use is between 3000°K and 5300°K, with a nice, comfortable sweet spot at around 4300°K. Source: I'm a former Lutron lighting control system designer.",
"The answer is going to depend on how the light is generated by the bowl. For instance, old-timey incandescent light bulbs generate light by heating up a Tungsten filament, creating black body radiation. If the tungsten is sufficiently hot, the light will appear white, but if it is not quite that hot it will have a yellowish tinge to it do to under-representation of blue and purple in its Spectrum. Other lights run current through gases or liquids in order to excite the molecules of those gases, which causes their electrons to enter higher shell levels. When those electrons drop back down to a lower level, they emit light in specific frequencies that generally have a specific color, but by mixing together various gases you can mix the colors produced to get a white light."
],
"score": [
11,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
be9bu8 | What are some real-world examples of CPU cores and threads in action? | I've searched online as well as this sub, and I've got the basic concept of 'cores vs. threads' (i.e. 'workers vs. tasks') but I can't find an explanation about how this affects the programs I'm using. If I've got a video game open, or running an anti-virus scan, or multiple things like this at once, how does the number of cores/threads impact these processes? Thanks! | Technology | explainlikeimfive | {
"a_id": [
"el40rkm",
"el44lef"
],
"text": [
"The amount of cores is the amount of little dudes in your PC and the threads are the things you want them to do. If you have just one core/dude and you wanna play some Fortnite (amirite kids) but you also wanna calculate a billion digits of pi at the same time, that guy has to put in the work, switching back and forth between the two tasks. If you have two cores, the dudes can split the work. One dude is making Fortnite run and the other guy can slave away at those digits. & nbsp; The GPU is a great example of the advantages of many cores. Your graphics card is filled to the brim with tiny dudes, way less knowledgeable than the CPU dudes. You could almost call them one trick ponies, because they are really good at turning some numbers into triangles but aren't super duper useful for a whole lot more. Now if your CPU was also responsible for the image on your screen, you wouldn't be in for a fun time, because it's too much work for the CPU. This is where the GPU has it's moment in the spotlight, because the loadsa tiny dudes can split the huge workload.",
"Let's start with how things work with a single core. The OS divides your time into slices. Let's say 10ms per slice. That means that 100 times per second, the OS decides what should be running now. So you start running a game, which is CPU intensive. Let's say your computer is just fast enough to run it, so it takes all 100 available slices at runs at 50 FPS (randomly picked numbers just to have round numbers). In the background, the antivirus kicks in. The antivirus needs to run, and the OS must give it some time. Let's say the OS decides the antivirus is less important than the game, so it gets 30 of the total 100 slices available. The game has 70 slices left. Your FPS drops to 35. Plus it's probably jumpy, as for instance the OS may give the antivirus several slices in a row, with the result that your game gets stuck during a frame or two. Now add a core. What that means is that you get another 100 slices. But rather than just having 200 slices total it's really more like 100+100. A single thread can only use one core. You need multiple threads to take advantage of the rest. So you start the game. Your game happens to be single threaded. The game gets 100 slices, and the other core sits idle. Then the antivirus kicks in. Well, you have one core doing nothing, so the OS doesn't even have to divide the time -- the antivirus gets the 100 idle slices for itself, while your game keeps on running just like before. Not only the antivirus doesn't bother you now, it finishes its work faster. Now let's say that the game gets an update and is improved. It's still majorly single threaded, but with multiple cores it can load stuff in the background better. As you move through the level, the game needs to load what's ahead, and with a single core that competes with the calculations needed to just draw the game. So with one core, your FPS drops to 40 as you come close to the point where the game needs to load more data. With multiple cores, this improves. As you get to that point, the game starts a thread. It runs on the second core, and takes 100 slices -- but just for a second or two, while stuff loads. The game still runs at 50 FPS, but you get a a more consistent performance --- always smooth, no slowdowns. Then there's a further update. The programmers reworked the game for multicore. Now part of the work can be in parallel. This means the game can now take up to 130 slices on a constant basis, and now it runs at 65 FPS on the same hardware."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
bec53n | Why can we see 55 million light years away but we can’t (haven’t) zoomed into planets some where much close to check if there mobility/intelligent life? | This has always puzzled me. Why can we take a picture from 55 million light years away but we can’t or haven’t (??), per se, gone 27.5 million light years away and focused on any planet within some system and tried to see if there are life forms moving around. Or even those reasonably distanced like a few thousand light years to get a really good picture. Edit: Thank you everyone for the reply. I believe I understand now, it’s that the object that typically we take pictures of are massive while the life on other planets would be super tiny in comparison. Really appreciate all the comments! | Technology | explainlikeimfive | {
"a_id": [
"el4nbkb",
"el4n11g",
"el4okx0",
"el4mvem"
],
"text": [
"We have trouble looking at really small things. The black hole was very far away but it was also enormous and even that photo was blurry. URL_0 Xkcd put together a nice size comparison to show exactly how big that black hole is",
"Due to the physics limits on focusing light, we don't have the ability to zoom in that well. At the distance of the closest star, we can't even make out a *whole continent* let alone individual life forms. At the distance of a typical star, it just gets worse.",
"The reason is because camera resolution is not just about zooming in, after a point the physics of light prevents you of zooming in more with a particular camera, our digital sensors easily get to their limit, to improve the zoom you must have a camera lenses (or mirror in the case of a telescope) that is physically larger. This is why a pro SLR camera just makes better pictures, they both get very close to the limit of the lens, so a bigger lens diameter makes a better picture. That's why telescopes are typically measured by their diameter, for telescopes diameter basically equals zoom strength. Now, no normal telescope can take a picture of something like a black hole, even in our own galaxy, they just don't have that kind of zoom. What they did for the black hole camera is built a theoretical telescope by combining telescopes at opposite ends of the world, and use a whole bunch of math to do this. Optical telescopes can't be combined (yet) this way, so they used radio telescopes. But this combining meant they had the performance similar to an earth sized telescope. Now, for pictures of planets, they are much smaller, I would estimate they need a telescope thousands of times bigger than the one that was used to see the black hole (as the area around a black hole is larger than a planet, you're asking for maybe 5 meter accuracy which is thousands of times smaller than what they measured, and they used radio, the surface of a planet doesn't give off much radio signals). Looking a couple times closer only gets you a couple times smaller telescope requirement, not the thousands we need. So the telescope that we'd need a an optical telescope that's probably earth orbit sized. Not only is that impossible to build, even if we did a synthetic type telescope (as the black hole team did), they'd need multiple telescopes in orbit. We still have a ways to go (but hopefully not too much) before that's possible with radio telescopes. And with optical telescopes, that's probably a long ways off with what our tech can do (I do think it's possible, but not for a long time).",
"The recent blackhole photo that triggered your question is a rather fuzzy picture of a very large area of space. If we use life on earth as an example, most life on this planet is very small bacteria, yeasts, insects and other invertebrates. Only a handful of mammals are large enough to be seen from space. Even from the moon it would be difficult to see a blue whale, forget about being able to see a creature that size from mars."
],
"score": [
14,
10,
4,
3
],
"text_urls": [
[
"https://xkcd.com/2135/"
],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
behjym | How can you work out when a photo was taken (what is exif data)? | I'm vaguely aware that exif (?) data is a thing, but how can you take a random photo on the internet and work out when it was taken? If you save the image at a later date does this data change? Is it a visual thing hidden in the image or do you have to look at the file somehow, in which case can it be hidden? | Technology | explainlikeimfive | {
"a_id": [
"el5yp7f"
],
"text": [
"Exif data are informations stored within the photo file itself. You can see them for example (in Windows) under the \"details\" tab in file settings (I hope it's \"details\" because I only use Windows in Polish :') ) or in some more specialised \"exif viewer\" apps or websites. The exif data contains various information: basic stuff like resolution or file creation date, which is available for every photo file and more \"spicy\" stuff like exact camera settings (shutter time, ISO, these kinds of stuff) or even GPS coordinates of the place where it was taken (if the camera supports geo-location, most phones do and ask you the first time you use the camera if you want this information saved). As for taking a photo from the internet and getting the informations out of it, it's not that easy. If the photo you download is the original file then the exif data is probably intact. If it's not the same file and it's been processed a bit (like Facebook photos) then most of the data is probably overwritten, both as a product of modifying the file and saving it as a whole new one and intention to protect the owners' privacy(mostly the first part, though). I'd suggest to just try for yourself, save some random photos from the internet, take some with your phone, camera and explore the exif data ;)"
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
behnt8 | How do wheelchairs that are controlled by people blowing into the straw-like tube function? | Basically wondering how it works in general and then how it could control things like speed and turning corners and so on. | Technology | explainlikeimfive | {
"a_id": [
"el63lvt"
],
"text": [
"Wow something I know about! I used to work on designing these kind of devices. The straw is connected to a pressure sensor which can detect blows and sucks of different intensity. At a most basic level you can either blow or suck on the straw. On top of that it is usually split into hard and soft blow/sucks. That gives you four actions which corresponds to the four directions. For experienced drivers forward is usually latching which means that the chair keeps driving forward until it is cancelled by a reverse action. This let's the driver turn while still moving forwards. Finally, the driver can increase the speed by repeating the forward action which gives them more control."
],
"score": [
25
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
beibmt | How are some publishers' games "playable" at just 20% of the download? | Technology | explainlikeimfive | {
"a_id": [
"el637yf"
],
"text": [
"A huge portion of the disk space taken up by a game may be items like maps, video/audio files, higher resolution textures, etc The actual base code needed to run is often very small in comparison. If the downloader prioritizes the base code and enough of the resources to play a level or two, the whole game may not need to be downloaded just to start playing. The downside of course is that some features may not be available and the game won't let you play a level that has missing assetts."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bejkqt | how do colourblind correcting lenses work? | Technology | explainlikeimfive | {
"a_id": [
"el6b5p1"
],
"text": [
"There are mild forms of colorblindness called anomalous color vision. With that condition, you still see all colors, but since, say, red and green are more similar than for people with normal color vision, you will find it harder to distinguish between hues in that range. A majority of the people called colorblind are actually just anomalous, and not totally anopic. Colorblind glasses like Enchroma are essentially fancy color filters that \"cut out\" some of the more ambiguous wavelengths, making reds redder and greens greener, so a bit of that distinction is restored. It cannot help people who can just perceive one or two colors. There are some other tricks for that though, like using different lenses for each eye and hoping the brain adapts to that."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bejmgf | How do "stream hack" or youtube-to-mp3 websites work, and how do they not get struck with massive copyright strikes? | This came up in a conversation at my work place and got curious. There is a website my friends at work used to get free music without torrenting or pirating, saying that it was free and had no issues. I did a little research into it, and I found out there's dozens of sites ridden with click bait malware ads and hard to get through pop ups, but usually the MP3 is easy to get. My ELI5 question is how are they not constantly taken down for copyright violations, and how do they even turn a YT video into an mp3 with stream hacking? | Technology | explainlikeimfive | {
"a_id": [
"el6bcbi",
"el76nt4",
"el6c31s"
],
"text": [
"Every content you get by browsing the web is temporarily stored on your device. So it's not really hard to save it. For copyrighted material it's the use you make of it when you receive it the real issue, but there's no way to prevent you from saving it. Content providers can only try to make it as hard as possible. In particular for youtube mp3 grabber sites in principle there is no proof that what you're downloading is copyright protected, it's just a tool.",
"You don't even need to go to some shady website. You can just install a browser plugin to do it directly from YouTube.",
"To watch the video on YouTube the data is sent to you, it is sent in lots of different formats depending on how you are watching it (flash, HTML5, etc.)... some of these send audio data and video data separately and they are stitched back together by your browser for you to watch the video. That means that somewhere in your temporary data folder, browser cache, wherever it has gone, the video and audio data is sitting there, that’s how the video buffers, these websites have servers (or offer programs that let you do it and be your own server) which look at this data for you and save it as a file you can use later. Copyright is a bizarre area but basically, they are breaking copyright by making a copy, but who “owns” the video could be disputed, does YouTube own it or does the video creator? The creator gets the ad revenue so you could argue they own it, but they wouldn’t be able to tell if someone has watched the video or if someone has saved the data, because either way the data has been sent out from YouTubes servers in the same format as it would for any viewer. YouTube could attempt to look for the IP address of the server that is copying the videos but YouTube doesn’t have much claim to the videos on its platform, again, because the video creator owns them. YouTube instead attempts to combat this by coming up with new and interesting ways to store the data that is sent, going into all sorts of encryption and verification in an attempt to break the software these websites / programs are using, and it usually works... until they figure out how to hack it again."
],
"score": [
11,
5,
5
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
benmnv | how do smartphone apps know how far you’ve walked, and how long you’ve slept vs. how long you’ve been in bed? | Was having a walk in San Fran, was curious how my phone figured out the data above despite being on airplane mode! | Technology | explainlikeimfive | {
"a_id": [
"el75gdn",
"el74k9g"
],
"text": [
"It’s based on movement, but it’s not perfect. I have a Fitbit that I don’t wear at night, and it’s usually smart enough to realize that I’ve taken it off instead of sleeping perfectly still for 10 hours straight. But if I take it off for an hour while I’m cooking or showering, it often believes that I just took a 1 hour nap. A newer model that monitors pulse rate might be better at knowing if somebody’s asleep and *much* better at knowing when the watch has simply been taken off... But they’re just using a system of sensors and a (fairly good) algorithm to figure out what kinds of motion are associated with sleep, they aren’t reading your mind or checking whether your eyes are open (yet).",
"Steps are easy due to the sensors in your phone, sleep is more or less accurate depending on how you use your phone. If you're the type to throw your phone on the charger at bedtime then grab it off the charger first thing in the morning, it's going to be far more accurate than the person who puts their phone on the charger after work and lets it sit until they leave for work the next day. In short, lots of data has been collected regarding usage patterns, that data has been analyzed to determine what normal usage patterns for specific activity looks like. Your phone uses that information to *guess* when you go to bed, wake up, etc. The accuracy of such guesses depends highly on how you use your phone. EDIT: Additionally many use their phone as alarms in the morning, this makes it really easy to tell when someone wakes up (alarm went off, alarm was turned off and phone was taken off the charger, person is awake)."
],
"score": [
5,
5
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
beqpor | What were the noises a modem made and why did it make them? | Technology | explainlikeimfive | {
"a_id": [
"el7vjl2"
],
"text": [
"The sound was the way a modem turned data into something that can travel down the phone line. Typically a modem was configured to play the sound on its built-in speaker until the connection was established, at which point the speaker would turn off and the modem would be silent. This was useful for the user because the sound would change in an obvious way once the connection had been established, and if there was a problem you knew to step in and do something. You could also turn off the modem's speaker completely, if you were so inclined."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
beu18f | How do bathroom scales measure things like body fat % and water weight? | Technology | explainlikeimfive | {
"a_id": [
"el8k18h",
"el9p1ut"
],
"text": [
"An electrical signal is sent from the bottom of one foot to another and resistance is measured. The greater the resistance the greater the body fat of the subject, in theory.",
"poorly. so much so that many product review groups have categorically rejected them as useful. on paper, they measure your electrical resistance and capacitance and use very general modeling assumptions to take a guess. in practice, these factors are impacted by *everything.* hydration, age, skin condition, what season it is (no, seriously), etc."
],
"score": [
10,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bevbra | How do companies know if passwords were leaked? Is there some sort of digital alarm? | Technology | explainlikeimfive | {
"a_id": [
"el8vmyt"
],
"text": [
"Not exactly. Imagine going into your house one day and noticing one of your windows is cracked open. You aren’t quite sure how long it’s been like that. You go over to the window and notice muddy smudges on the wall beneath the window, and one of the plants in the window sill is knocked over. (The digital equivalent here might be a supposed admin login from an IP address in a weird foreign country, or at a weird time.) You reasonably conclude someone has snuck in your window recently. The next step is to assess the damage. What could the intruder access via that window? Does it lead to a locked garage separate from the rest of your house, or straight into your bedroom where you keep your passport? Wherever it leads, assume the intruder saw everything they could get their hands on. Another way you might find out about your cracked window is from your neighbor. Rather than breaking in themselves, your neighbor is dope tells you it’s open. Maybe you give them $20 as a thank you. Companies would call your neighbor a “white hat” (while a malicious intruder would be a “black hat”), and many companies pay white hat penetration testers to try to find vulnerabilities in their security"
],
"score": [
13
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bevoum | How does a program such as Handbrake rip DVDs (home videos) into MP4s using only a disk drive ? | Technology | explainlikeimfive | {
"a_id": [
"el8x43q",
"el8zoa6"
],
"text": [
"What more do you need than a source material, a writeable destination, and a computer capable of deciding/encoding a video?.",
"It reads the data stream from DVD into memory, decodes it, encodes it into MP4 and writes it to disk drive."
],
"score": [
8,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bf6zns | How did I receive a text message that's different from the sender's original text? | Technology | explainlikeimfive | {
"a_id": [
"elbd4uw"
],
"text": [
"The way messages are sent is actually pretty complicated. Basically, each letter is sent as a few binary digits (I think 24?) and received with some mistakes expected, and it's translated back to whatever it's closest to. To make it cheaper, common things like \"tion\", \"ford\", and \"ire\" are treated as one letter. It seems like there were more mistakes on the way than normal. Edit: [here]( URL_0 ) 's the numberphile video I learned this from"
],
"score": [
14
],
"text_urls": [
[
"https://youtu.be/T46FTuHnbvY"
]
]
} | [
"url"
] | [
"url"
] |
|
bf7sak | How does the hardware in a computer (capacitors, diodes, transistors, etc) process logical information? How does it go from electricity applied to a circuit board to a video on my screen? | Technology | explainlikeimfive | {
"a_id": [
"elbkv30"
],
"text": [
"Layers of complexity. One bit is the most basic element, and that is stored by a few transistors arranged in a flip-flop device. A byte is simply eight of those right next to each other. A CPU at its core is an adder (two registers of 64bits and a register to store the result of the binary adder). To multiply, you simply add repeatedly. And so forth...until you’ve implemented a bunch of machine instructions of increasing complexity. Then you can create higher-level languages so you don’t have to deal in machine code. You can make basic software (drivers) that tell the machine how to interact with certain hardware to do simple things - like how to turn one pixel a particular color. Then you tell it how to arrange pixels to display text, images, etc. Then you write programs on how to display groups of text, buttons, animations, etc. Along the way, various platforms and standards are created so you don’t have to reinvent the wheel. If you want to display “Hello World” on the screen, it’s 5 lines of code or less in just about any language, instead of having to build all the device interface layers up from the single-bit transistor you started with."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bfca2u | How are video games developed for different platforms? How are they made to be consistent with each other? | Technology | explainlikeimfive | {
"a_id": [
"elcme2d",
"elckqwm"
],
"text": [
"These days most of the same code is used for all platforms. Generally speaking anything to do with the \"simulation\" aspects of the game e.g. physics, AI, gameplay, is written once and used on all platforms. The code that need to be different are the bits that interact with the hardware and operating system. Graphics is a big one, but there's also audio, controller input, stuff relating to save games and other features provided by the system software. Often these things are similar enough that you can write an \"abstraction layer\" which the rest of the code can use. And then the platform specific bits sort of \"plug in\" to that. It used to be different though. From around the PS1 era and before, games often would be completely rewritten for different platforms. They might have used code for another platform as a reference, but often they weren't completely consistent with each other.",
"Short answer if you're familiar with code: There are helpful middlemen pieces of code called 'interfaces' written, super-generic (not specific to any game), for different platforms, which people writing higher-level code can just call and use instead of worrying about details specific to the device. Longer answer: **Code is always made of different layers of abstraction.** When you typed out your question, did you think about what you MEANT to say? Or about the individual words? How about the individual letters? How about the individual movements your fingers have to make to press the various keys? Hope you get the point i'm trying to make. In the previous paragraph, i went from 'higher level abstractions' to 'lower level abstractions'. Can you even type if you have to think along the lines of the lower level abstractions? When you tell a guitarist he needs to give you the rhythm while you sing, will you just sing and let him handle the rest? Or tell him what chords to play? Or tell him where to put his individual fingers on the guitar? When you send mail, would you just write an address on the envelope, put a stamp on it, and leave it to the post office to make sure it reaches? Or give explicit instructions to the mailman on how to find the house? Or tell him how to move his legs or what muscles to use? So as a programmer you want to write complicated behavior in terms of higher and higher abstractions like move_character_to_place to build on top of it instead of finicking about with lower level details like what signal to send to the sound card or the screen all the time. And that's what helps with porting to different as well. If you write code using this heirarchy of abstractions way, it's just a \"replace\" of the lower level abstractions from one type of device to another. Examples being drawing something on the screen or some lighting stuff or playing sound. You just want to ask for those things, not worry about their inner details. Of course, the cost is customized optimization. Like how you may be a guitar expert and know a better way to play a certain song on guitar and just tell your guy where to put his fingers sometimes. But if you do that, porting to a different guitarist is difficult again. Same with the mailman. I mean the recpient might just be behind the house, or you might know a shortcut, or there's a dangerous dog at the gate to look out for, but you can't convey all that to the mailman. You get the point, hopefully."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bfdve9 | LED lights vs incandescent bulbs | Why does it seem that led lights are brighter then incandescent bulbs but incandescent bulbs seem to illuminate a distance further away than LED lights do? I have recently replaced my carriage lights on the front of my house. The incandescent bulbs seemed to light up most of my driveway. The LED lights have the front of my driveway much brighter but it seems less of my driveway is illuminated. in case it matters, I chose 5000K 1080 Lumens LED light bulbs. | Technology | explainlikeimfive | {
"a_id": [
"eld0ecr"
],
"text": [
"It IS more directional, that is totally correct. Think of this: old incandescent lights have a filament suspended in the middle of the bulb on two thin wires. That helps throw light out in all directions, in an almost 360 degree arc around the whole thing. LEDs are usually soldered to a driver board. That will give you 180 degrees of light at the most, as the light sits flat to the board. It takes more LEDs or diffractors to spread that light farther."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bfgb0m | Why is it that when you take a photo of your computer screen with a phone camera, the image is distorted or has some sort of pattern superimposed onto it until you zoom in on the image? | Technology | explainlikeimfive | {
"a_id": [
"eldf83a"
],
"text": [
"They're called [Moiré patterns]( URL_0 ) The pixel grid in the camera's sensor, the pixel grid on the screen your photographing **and** the pixel grid on your phone's screen (that's why it changes when you zoom) are not perfectly aligned and create an interference pattern. The same thing occurs when you take a picture of window screen."
],
"score": [
14
],
"text_urls": [
[
"http://en.wikipedia.org/wiki/Moir%C3%A9_pattern"
]
]
} | [
"url"
] | [
"url"
] |
|
bfoyeg | Ever Played DuckHunt? How did that gun even work? | Technology | explainlikeimfive | {
"a_id": [
"elf6s42"
],
"text": [
"The gun is a light sensor. When you pulled the trigger, your tv screen went black except for a white spot where the duck was. You could fake it out by pointing the gun at a light source instead of the tv."
],
"score": [
56
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
bfp1gn | what is “tuning a car”? | All I know is I can click a few options in need for speed and now my car is faster. I don’t understand mechanics or engines at all. Can I tune a Geo Tracker, or can only nice cars be tuned? | Technology | explainlikeimfive | {
"a_id": [
"elf83mz"
],
"text": [
"There are a lot of parameters in cars that are possible to adjust. Many of those, in regular family cars, are set to medium values for longevity’s sake for the car. Tuned cars have some of those values set to more aggressive values, or physically changed to affect the performance. Tuning a car might involve changing the shifting setpoints, adjusting the fuel-air ratio for different combustion power. Changing the shifting points may affect the overall life of the transmission components a little bit, but the performance improvement may be worth it to the driver."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
bfpw7b | How do video game engines work and how do they last so long? | Technology | explainlikeimfive | {
"a_id": [
"elfigck",
"elfik88",
"elffhgv"
],
"text": [
"When they say the same engine has been used for that length of time, they don't mean it has literally stayed the same all those years. It will have been continuously updated throughout that time. I work on a game engine that has been in use by company for over 15 years, but there are only a few core bits of code that still exist from back then. The rest of it gets updated or replaced as new technology and techniques are developed. The way we work, all these updates happen alongside games being developed on it. We don't stop development on the \"old\" engine and start using the \"new one\", it's continuous development.",
"> How do video game engines work? Essentially engines are a collection of frameworks and tools that form the foundation to the game. If you think about video games there are some thing you would expect all of them to share. All of them have some graphics pipeline. Most of them have some physics simulation. They all use textures, or fetch data from the hard drive, or utilize similar code libraries. The engine makes it so that developers don't have to start every project re-inventing the wheel, and can instantly start working on the game itself. Instead of programming in a physics engine the programmer can put in an object and tell the engine \"This object has physics, and uses a gravity of 1.4\". The engine handles the rest. > How (or why) do they last so long? Generally they get patched and fixed and are in active development so they can better function as the years pass. These hotfixes help keep the engine relevant and longer lasting. especially given that most things in the foundation don't relly need to change. Physics probably hasn't changed all that much in 20 years. Eventually those hotfixes start dragging behind, and the engine has to be essentially torn down and built from the grounds up to utilize new technologies and design philosophies. Mostly this is done when the graphics capabilities of the engine is incapable of keeping up with the ever increasing demands of graphics.",
"Not a game developer but I did some programming. Game engines are a little bit like a blueprint. They contains thinks that make the development of games easier by implementing physical abilities like time or motion and rendering abilities like giving an object inside the computer a picture for the user to see. The engine itself does not have to be the newest one simply because it mostly processes physical problems. This includes the ability for the developer to create an object inside a game in a few clicks and the object would have all physical abilities needed provided by the engine. Since physics and graphic rendering never really changed, old engines can be as good as new ones. But new engines can process things better by using new commands available from the processor or by implementing new calculation methods."
],
"score": [
20,
7,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bft541 | Why do CPUs and GPUs perform better when cool | Technology | explainlikeimfive | {
"a_id": [
"elg91zm",
"elg642i",
"elgc28x",
"elgrl9d",
"elhc4bn",
"elglk2o"
],
"text": [
"There is no such thing as a zero resistance conductor outside of superconductors. Resistance means the electrons are slowed down as they move through the wire or component, almost like friction, and that generates heat. The more electricity you try to pass through a thing, the more heat is generated. At some point, the temperature will be above the failure point of the component and it will get damaged. CPUs and GPUs have what is called a *clock speed*. Think of a string of binary code, that might be something like 0101100101. How does the computer know that it's two 1s or two 0s in a row? What if there are three, or four, or five 1s or 0s in a row? How does the computer know when one 1 stops and the next 1 begins? There is a clock that only ever goes 10101010... Each digit is a flip that drives the rest of the chip. The faster that clock goes, the faster everything else goes, too. But making the clock go faster means pushing more electricity through the chip. If your clock speed is too high, you generate too much heat and your chip is damaged and stops working. Built into your computer are two limiters. One of them is a thermostat that will limit your clock speed when the computer gets too hot. This is called thermal throttling. The other is like a governor on your clock speed that the manufacturer says is the maximum safe clock speed. You can tell the computer to have a higher default clock speed above that preset maximum, but it may not be stable because it will spike the temperatures up faster than it can be reliably throttled down and cause problems. If you keep your computer cooler with better cooling devices, like bigger, better heat sinks and fans, water cooling blocks, liquid nitrogen, or even liquid helium, you can increase the clock speed that your chip runs at without the chip overheating and becoming damaged or unstable.",
"Many motherboards will decrease CPU and GPU performance when it gets too hot. This is to prevent damaging the chip. Also, heat will wear the microcomponents inside the chip. However, heat really won't affect the performance of the chip, not regarding the motherboard's automatic underclocking and decrease of using resources. This is also why if you would like to overclock, you need to make sure you have good cooling.",
"as a rule, electrical resistance increases with temperature, which decreases performance. however, most computers are programmed to throttle performance in response to heat in order to protect itself.",
"The speed doesn't depend on heat. However the computer will slow down the CPUs and GPUs when they become too hot to prevent them from melting (self destroying) so what you see is hot CPUs/GPUs becoming slower.",
"Lots of great in-depth information in this thread, but the short, simple response is that they *don't* perform significantly better when cool. However, sustained high temperatures will shorten the lifespan of the semiconductors, and extremely high temperatures will damage them rapidly. Running faster generates more heat, so better cooling allows that heat to be taken away more effectively, meaning they can reach higher speeds without climbing to harmful temperatures. **TL;DR genuine ELI5:** It's not that running cool helps them perform better; it's that running fast makes heat, running hot is bad for them, and better cooling makes it possible for them to run faster without breaking from getting too hot.",
"They have an internal mechanism that keeps them from burning up. It works by throttling back when the chip gets too hot. So if you keep it cool you keep it running at the max speed."
],
"score": [
203,
62,
25,
5,
5,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bfu7du | Why do banks use Apple/Google pay for contactless payments instead of their own apps? | Technology | explainlikeimfive | {
"a_id": [
"elgcil1",
"elge9r5"
],
"text": [
"Because much more people use google or Apple Pay instead of the banking organisations one allowing the aforementioned to be much more polished and user friendly",
"The big money here is in the card transaction fees, not in what Google and Apple get. Particularly in the US, those card fees are high and they go to the banks, credit card companies and the processing companies. Because each bank would need its own app, it’s easier and cheaper for them to get Apple and Google to handle that part while they make the big money with the card fees. And before the credit card shills land on my comment with their disinformation bullshit (they always do), Stripe charges 2.9% in the US and 1.4% in Europe. There is both competition and pricing regulation in Europe with credit cards, both of which are essentially nonexistent in the US."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
bfucm5 | How do noise canceling headphones work? | Technology | explainlikeimfive | {
"a_id": [
"elgeraj",
"elgexnz",
"elgky39",
"elgktvc"
],
"text": [
"The sound is a wave, including wave length, amplitude and frequency. Basically, if you 2 sounds with the same frequency and wave lenght but the opposite amplitude you wont have anything left (work with light on certain conditions). So the headset sounds the opposite of the \"outside\" cancelling the sound. edit: the headset \"hear\" the noise first, in order to cancelling it. Sorry for bad english, I' mfrench",
"They sense the noise coming in and then create a noise that is the exact opposite of whatever is coming in. Sound is like waves on the ocean. If you were able to create waves going the opposite direction that are high when the ocean waves are low, or low when the ocean waves were high, you would just see flat, still water. If you do the same with sound, you get silence",
"Imagine that the sound coming from outside is +1 and the headphones process this information and release a -1 sound the end result is +1-1=0.",
"The headphones listen to ambient noise and play the inverse polarity through the headphones. When the ambient sound meets the inverse of that sound they annihilate each other."
],
"score": [
10,
8,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.