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fcdf3v
|
What is Perfect Forward Secrecy and how does it work? Is it really perfect secrecy in practice??
|
I keep on reading about Perfect Forward Secrecy. Can someone ELI5 what it is and how it works?? Also is it really perfect secrecy in practice?
|
Technology
|
explainlikeimfive
|
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"text": [
"PFS means that even if one server's private key is compromised, the session keys it protected are not known. It's a protocol characteristic, not a one-size-fits-all sort of thing. The concept is to choose session keys in a way that later disclosing the server key doesn't mean that all the old messages encrypted with the session keys can be decrypted."
],
"score": [
3
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|
[
"url"
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[
"url"
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fcejkh
|
How do our phones know that we’re touching them and exactly where we touch them?
|
Technology
|
explainlikeimfive
|
{
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"fja93ki"
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"text": [
"Electrons repel other electrons. This really simple fact is brilliantly exploited by phones. By moving electrons into and out of pixels on the screen, our phones can detect the presence of nearby conductors. Something like metal makes it really easy to move electrons in and out of the screen. Something like rubber or air makes no difference. Flesh is somewhere between the two. The phone detects places where the electrons move in and out of the screen more easily *but not too easily* and knows that a finger or finger-like-thing must be touching the screen there."
],
"score": [
3
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"text_urls": [
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|
[
"url"
] |
[
"url"
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|
fcffst
|
How to use a washing machine? Parents (17m) out of the house and I have no idea how to wash my clothes.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjab3tl"
],
"text": [
"Put clothes in. Put soap in. Closed door. Turn on machine. Set to normal. Start. Wait for beep. Put in dryer."
],
"score": [
6
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
|
fcfro2
|
When a PC game downloads an update that is let's say 50 GB in size, do these 50 GB add to the existing let's say 80 GB the original base game was (to a total of 130 GB) or are parts of it replaced and not requiring additional disk space?
|
Technology
|
explainlikeimfive
|
{
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"There's no one answer for this. The patch could be entirely replacing existing data without changing file size, it could be adding new content not present in the install, or it can be any combination of the two. You'd have to check the patch notes.",
"It's 50GB of changes, but that could mean 50GB of new stuff or 50GB of replacing the old stuff. It's completely up to what the developers wanted to do.",
"It depends on if the update is to patch bugs or add new content. Let's say we have a house. There are some pieces of wood that have termites so we need to replace them. So we switch them out with good wood. Our house still contains practically the same amount of wood. Bugs fixed! But now we want to build a porch. So we get some new wood and put up our porch, so now our house is bigger, it contains more wood. New content added! tl;dr It depends mainly on the purpose of the update. If it's mainly a bug-fix patch, then a lot of that data is going to be replaced older data. If it's a content update, then it will be probably a lot of brand new data.",
"Basically, every patch that's released these days contains all the incremental updates of all previous patches so you only need to download this one patch file to be updated to latest from a v1.0. Yes, this is inefficient for people who keep their programs updated but developers these days cater to the lowest common denominator. The patchfile is basically one large executable that detects what verson you're on and updates or adds the necessary files and them deletes itself after or not.",
"A standard game updater would take in 3 types of commands: - add/replace file - patch file - delete file Adding/replacing a file is basically just writing/overwriting an existing file. Patching a file is when you only want to make small edits to a file, and you give instructions on how to modify file to do so (e.g. go to 10th character and replacing next 5 characters with these new 10 characters) Delete file, self explanatory. Which command it uses depends on how the update is generated, sometimes it makes more sense to just overwrite as a patch can be larger than the actual file. Real ELI5 attempt: if you eat 1kg of food, you don't necessarily gain 1kg in weight. It gets broken down and either converted to energy, stored, or passes right through your body. In fact some foods can cause you to lose weight because it costs more energy to digest than it gives you."
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"url"
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[
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|
fcha07
|
Where is all the really cool technology advancements that were to come thanks to Graphene? EG: Extremely sensitive camera sensors (no flash needed), Computer parts built with it that outperform silicon etc
|
Technology
|
explainlikeimfive
|
{
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"fjaopl1"
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"text": [
"It's not about the new technology existing, but about being cost-effective to mass-produce. Graphene is still far more expensive to produce than the minimal benefit that your average consumer would get out of it."
],
"score": [
4
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|
[
"url"
] |
[
"url"
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|
fckygi
|
What is the main objective (or how different are) jira, asana, monday, wrike, trello, etc?
|
Why are there so many of them and what do they do?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjbi0p1"
],
"text": [
"They are project management tools. When your business has a lot of tasks it needs to keep track of/measure/log billable time, then tools like those are great because instead of just monitoring an email box, or using a whiteboard, everything has its own ticket, and they can be sorted/commented/closed as needed. I'm speaking mostly for jira, because that's what I use at work. But I'm assuming the others are similar"
],
"score": [
3
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|
[
"url"
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[
"url"
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fclhty
|
When speeding up a video more and more, why do voices increase in pitch?
|
Technology
|
explainlikeimfive
|
{
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"fjbhcmy",
"fjbhhra"
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"text": [
"When you speed up a video it forces the sound to be played in a shorter amount of time. This means that the wavelength of the sound becomes shorter. The shorter the wavelength the higher pitch the sound is. This is the same reason when you slow down a video it sounds deeper. The wavelength is longer than the original.",
"Sounds are waves. The pitch is determined by the frequency of those waves. The faster the wave goes up and down, the higher the pitch. When you speed up a video, you are squeezing the sound waves into a smaller time frame. The same amount of ups and downs of the waves happen in a shorter amount of time. This is equivalent to changing the wave's frequency and will therefore result in a higher pitch. I think [this picture]( URL_0 ) does a good job explaining how the soundwave can changes. It also explains the relationship between the wave's amplitude and the sound's loudness."
],
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[
"url"
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[
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|
fcpdwz
|
how does forced perspective work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjcd0wu"
],
"text": [
"Naruto is the perfect example of a forced perspective. At the start of the show you believe that everyone that Naruto is fighting is evil. The reason that you believe that is because the show forces you into Naruto's perspective, and the people around Naruto tell him \"the person you're fighting is evil\". But as Naruto goes through his life he begins talking to his enemies and he discovers that his enemies believe that its actually Naruto and his friends that are evil while they're good. Then towards the end of the show you find out that the reason for all of this - the reason that everyone thinks that they're good and everyone else is evil - is because they just live in a really fucked up world that is stuck in a state of perpetual war. You could have been told all of that right at the outset of the show, but you aren't. Instead the show limits the information that you're presented with to only what Naruto knows and so you're forced to learn about the world that he lives in at the same rate that he does."
],
"score": [
3
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[
"url"
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[
"url"
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|
fcrr82
|
Why do unresponsive network operations freeze your computer?
|
Why can't the process check for user interrupts if you want to cancel the operation?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjcql6w"
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"text": [
"Because of cheaper (or lazy) programming. Every behavior could have been controlled, unless you go into extremely demanding math or graphics. However, the proper management of cases that should never occur is expensive and not very productive. The case of unresponsive network also has an additional problem when one has to decide what to do in that case. Something like \"Ok, I've controlled unresponsive network, now I must tell the system to... what? I have no network. Do I close? Do I show a message? Do I wait a bit more? But if I was going to wait a bit more, what was the point of controlling the situation? If I allow the system to move without network? What do I do when the network comes back? Do I store all user actions and dump them there? What if it's too late? As another way of thinking about it, separate \"network is down\" into \"network has been down for 10ms, 100ms, 1s, etc.\" It soon creates a long list of hard to decide situations that can take a lot of code to manage."
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9
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"url"
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[
"url"
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fcw240
|
If computers can process a billion tasks in a second, what actually happens when your computer gets really slow and takes 2 minutes to open the browser?
|
Technology
|
explainlikeimfive
|
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"text": [
"The primary reason you experience these slowdowns is resource contention. Your processor is rarely the bottleneck in your system. If all you want to do is a simple mathematical operation on a small amount of data, your processor can churn away at billions of tasks per second. But that's rarely what you want to do. Most of what's going on in your computer is moving data from one location to another - one resource to another. When you have a large number of different processes all trying to move resources over the same limited channels, you often run into problems where multiple processes want to use the same limited resource and have to wait their turn. Think of it like traffic on roads. Normally, it might take you 15 minutes to get to the grocer. But as you increase the total traffic, that time starts to spike upwards because there are other people using the roads you need to use.",
"A \"task,\" for the purposes of your sentence above, is simply adding two numbers together. There is a massive amount of \"tasks\" involved with even simply drawing a square on your screen. Opening a program involves loading it into memory, performing trillions of tasks to set it up, performing trillions more to start interpreting a web page, performing trillions more to display that page to your screen, etc etc...",
"Most of these answers aren't *wrong* per se - but when it comes to loading programs (like your browser) the main thing that's really bottlenecking the whole process is the speed of your disk. Your CPU and other components can't process jack until the program is pulled off your main drive and loaded in to RAM. Main disks (especially traditional spinning hard drives) are some of the slowest components in your computer, so the rest of the machine is stuck waiting for it to finish. That's why many modern systems ship with an SSD as their main disk instead of a traditional hard drive; since SSDs don't have any mechanical parts they're WAY faster and and significantly cut down on loading times. & #x200B; Now, if your program is still acting slow after it's already been loaded THAT'S when you need to start considering other factors like there being too little RAM, thermal throttling, unoptimized code, etc...",
"Short answer: theres a lot of things happening behind the scenes, some of which are waiting on other things to happen first. Think about making a cake but only working with the recipe instructions one line at a time. Step 1 Get flour: Simple the flour is right here already in the bowl on the counter, wont take any time to fetch (CPU Cache * special cpuRAM) Step 2 Get sugar: Less easy, I need to spend a few moments walking across the kitchen to the cupboard and fine where the sugar is, then bring it back (RAM) Step 3 Get eggs: Not as simple they are in the fridge (Harddrive) it's going to take me a few minutes to walk down into the basement, open the fridge (Harddrive) and find the eggs. Step 4 Get butter: Oh no, there isn't any in the house, I'll need to drive to the store (Internet) to buy some. At any one time you might not be able to predict what comes next. You might waste 2 minutes going to fetch 1 egg only to come back and find out you need to go get 1 more. Over and over again. When opening a browser, your computer will need to fetch the browsers program from your hard drive and put it in RAM which takes time. Then run the code, moving the important parts from RAM to CPU as needed. The browsers code will execute and before it even loads on screen it may have to fetch stuff from the internet, updates, your last viewed webpage, it may have to log you in. Then it loads as far as you can tell, even though it's been starting up in the background for a few ms. The core browser software is complicated and this translates to many billions of simple machine operations that all stack together to form what you see on screen. Additionally, the code the browser is running is dependant on other parts of your system, that also have to go through the same process. How does windows know you want a browser window on the desktop. How will the browser interface with your network card. All of this assumes that you computer is in ideal condition and is not bottlenecked by size of RAM (space on the cake making counter) or by the speed at which you can fetch stuff from the Hard drive (distance to the fridge / store). If your family members are all also trying to cook at the same time, you are going to run out of space, and might find yourself fighting for counter space( RAM) needing to put ingredients away to make space or queuing to get at the fridge ( harddrive).",
"In addition to the things others have already explained, there's also the issue that while our computers have gotten really fast the people who tell the computers how to do things for you (programmers) have, on average and with some noteable exceptions, stopped caring about telling the computer how to things *efficiently*.",
"There can be a variety of reasons but one example: Computers have a lot of ongoing tasks and processes which are depending on eachother since they all have to share time on the same processors. Often these timeouts occur due to an interdependency where a thread or process is waiting for it's turn, but the precious task or process has stalled (perhaps waiting for an input from another one). There are optimizations in place to prevent this to a certain degree but due to the large amount of potential programs, tasks, processes and activities interacting with eachother it still happens, even on high end systems."
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"url"
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[
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|
fczei6
|
How does the touchscreen element of some absolutely shattered screens still work?
|
Technology
|
explainlikeimfive
|
{
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"fje0rkw"
],
"text": [
"Touchscreens are actually made up of several different layers. If you only break the outer layer you can avoid damaging the actual \"touch sensitive\" bits. A touch screen display might goes something like: Outer glass (i.e. the bit you actually poke with your finger) Plastic \"bonding layer\" Actual touch sensitive bits often built on a 2nd piece of glass \"Nothing\" (air, plastic, literally no gap between the touch screen and display) The actual Display"
],
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6
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[
"url"
] |
[
"url"
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|
fd2r6q
|
How is it that when your computer is lagging really badly, but playing a song, that song still plays smoothly while everything else is unresponsive?
|
Technology
|
explainlikeimfive
|
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"Audio processes are often assigned some of the highest priority because stuttering audio is horrible and audio lag is some of the most notable. So there is a chance that the audio playback is one of the few things that has higher priority than whatever causes the hold up.",
"There are lots of reasons. One is simply that the operating system is designed that way: media playback is highly time critical so modern OSes prioritize it over other processes. Secondly, audio in particular is relatively low data rate. Audio playback is handled by dedicated hardware. Your application likely reads the audio data in to memory and then tells the hardware where in memory that data is. Once that’s done, the audio hardware can read directly from the memory. This means that the rest of the system, can, within reason, lose its mind and the audio will keep playing until the data in memory runs out. Source: I was the lead engineer on the port of a major non linear video editing system to MacOS. We had to do unholy things in order to stop iTunes from starving out our video hardware.",
"When you play sound, you have dedicated hardware which does all the decoding, buffering, playback and anything else. This for example allows you to play music on your phone while your phone is in your pocket. Also, your sound player usually keeps a buffer in memory, where the next few seconds are already decoded and are ready to be played back. This prevents your sound from lagging mostly.",
"Audio gets a high priority to interrupt and also requires very little data to sound reasonably good.",
"It's like the buffer on a youtube video. It downloads past a spot you are listening to and so long it can download faster than the music can catch up to the point its downloaded to, you're good!",
"The overall audio behavior is controlled by a combination of the hardware architecture and the audio driver stack. On the software side: the drivers are loaded at system startup, they reserve enough memory to not need more allocations later. The application typically reads ahead several MBs from storage so even if the access to filesystem is stuttery, nobody will notice. On the hardware side, almost all modern SOCs have dedicated audio codecs in hardware that will efficiently decode compressed audio into wave streams and pipe it directly to the audio channels with minimal intervention from the Processor cores that may be busy with whatever-is-causing-the-lagginess. I was thinking of a PC running Windows in this example, but I suspect the answer is true across most modern devices.",
"The computer spends more of its available processing power on the music to keep is playing consistently. It sacrifices other things responding as fast because it has to budget its power and it can't make itself faster.",
"When your computer is lagging it's often caused by the system waiting for something to load into memory from disk. The song is already in memory so plays without interruption.",
"Audio programmers use tricks to minimise costly system operations in the audio playback thread, like avoiding memory allocations, avoiding jumping around in memory if possible, avoiding disk accesses, using inline code instead of function calls, avoiding conditional statements so the instruction cache can make intelligent predictions, considering data structures and their sizes so that you can use the faster (but smaller) stack rather than the heap. Sometimes leads to programming practices that aren't textbook but you want to keep that audio buffer full as much as possible so that it is ready to send to the speakers immediately when it's needed. There are internal representation tricks like multiplying by a boolean TRUE (1) or FALSE (0) instead of using if statements to get a result or not if your language allows it. Languages with non garbage-collection memory management are better so that the system doesn't launch into expensive memory accounting through all your values chasing pointers at inconvenient times and affecting the audio thread. You also want perfect parallel processing to avoid deadlocks and chasing situations (see Rust!).",
"There are multiple factors at play, and multiple answers so far are correct. However, even with dedicated hardware, a slow PC can still eventually cause audio issues. The truth is, computers are *really* bad at doing multiple things at once. While there is some capability of parallel processing, for the most part, computers are better thought of as just doing one single thing at a time, but really really quickly. The only reason it seems to you that multiple things are happening at once is because it flips between each of the different running processes so quickly that, to you, it looks like it's happening at the same time. However, the operating system gets to decide which things are more important than others, and so does not give everything equal chance to run as it's flipping between everything. Some will get their chance more often, or for a longer duration. When a computer is slow, or \"lagging\", this is often caused by some process on the computer that is taking up too many resources. Audio processing is often treated as more important than many other things however, so it still gets it chance to run, even though the thing taking all of the resources is slowing down the rest of the computer.",
"Playing music doesn't take much processing power. A mid-to-late 90s computer could manage to play an mp3 just barely while doing nothing else. 20+ years of improvement since is all gravy. Computers can do that shit in their sleep now.",
"It means your audio driver didn’t freeze but the video decoder froze. They are two different things controlled by two different drivers.",
"The answer about prioritization is wrong. The reason is because audio is not processed through the CPU. Audio in the PC architecture used to be an add-on card you had to buy. Anyone remember Soundblaster? URL_0 Initiating sound goes through the CPU, but the continuous play of audio is entirely managed by a sub-set of the system that does not follow through the CPU. The result: your audio program can lock and and keep playing a playlist, but you can't make it respond to mouse commands, or even your controls and keyboard are locked.",
"Modern processors have a variety of extensions that are designed to specifically do certain tasks way, way better than the main processor can by specializing them. Decoding of various very common media encoding methods is a common use of these extensions, as it allows the system to process it faster, with less power usage than using the main processor, and while taking the work off of the main processor to leave it open to do other things. So often you'll see exactly this result, where something related to decoding audio or video can run smoothly while the system works hard at other tasks it isn't optimized for.",
"Just thought I’d add that it is possible to get audio stuttering from things which may be surprisingly unrelated or of generally lower priority. I have seen it caused by a bad network adapter, for example. I use this software for testing: URL_0 This is their explanation: The audio latency problem Windows is not a real-time operating system. All requests to the operating system are delivered on a best effort basis. There are no guarantees whatsoever that requests are delivered within a certain time frame, which are the characteristics of a real-time operating system. That is not a problem for most devices and tasks but this is bad news for audio applications (which are considered soft real-time) because they need to deliver data to the subsystem and the hardware in buffers several times per second. If one or more buffers miss their deadlines and are not delivered in time it has audible consequences which are recognized as dropouts, clicks and pops. About DPCs and ISRs The Windows thread disptacher (also known as scheduler) which is part of the kernel executes threads based on a priority scheme. Threads with higher priority will be given a longer execution time (also known as quantum or time slice) than threads with a lower priority. However the kernel also knows other types of units of execution known as interrupt service routines (ISRs). Devices connected to the system may interrupt on a connected CPU and cause their interrupt service routines to execute. An interrupt can occur on the same processor that an audio program is running on. Any thread that was running on the processor on which an interrupt occured will be temporarily halted regardless of its priority. The interrupt service routine (ISR) is executed and may schedule a DPC (Deferred Procedure Call) to offload an amount of work. The DPC will most likely run immediately on the same processor which means the audio application will halt until both the ISR and the DPC routines have finished execution. That is because ISRs and DPCs run at elevated IRQL which means they cannot become preempted by the thread dispatcher (scheduler). Therefore to guarantee responsiveness of the system, ISR and DPC routines should execute as fast as possible. Guidelines say that they should not spend more than 100 µs of execution time however this is often not reached due to hardware factors beyond the control of the driver developer. If execution time gets too high, the audio program may be unable to deliver audio buffers to the hardware in a timely manner."
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[
"url"
] |
[
"url"
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|
fd754c
|
Why is it that on different phone's, some emojis do not show? Shouldn't it just register as text?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjfny5w",
"fjfoh7r"
],
"text": [
"Emoji are part of the Unicode system. In the actual message your phone sends, they're represented by a number along with a prefix that says \"this is Unicode.\" When the receiving phone gets a number that starts with this prefix, it knows to go to a library and look up a symbol using that number. Then it displays that symbol. If the phone's library is missing or incomplete (Unicode is biiig, and it would take a lot of space to store all those pictures), then it shows a blank character, or possibly just the Unicode number it got.",
"Emoji is basically a font Some devices either don’t have that font or do not have the most updated version of the font."
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9,
5
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[
"url"
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[
"url"
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|
fd9l8a
|
What exactly does OLED display mean? And how is it different from LED displays? Is one better than the other?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjg24tc"
],
"text": [
"OLED should^TM be a display in which each subpixel is a separate organic light emitting diode and nothing else, unlike LED displays which use light emitting diodes as a backlight for two layers of polarized liquid crystal and one or more fluorescent or phosphorescent layers which give subpixels their colours. An OLED display can completely turn off each individual subpixel simply by cutting power giving infinite contrast ratio and lower power consumption when browsing reddit in night mode, LCD displays can at best cut power to zones of the backlight if everything in that zone is black and even then will often have some light leak from adjacent zones. Edit: to really ELI5 it, OLED screens are a bunch of tiny lamps that make a picture, while LED backlit LCDs use shadows to make the picture."
],
"score": [
8
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
fd9w70
|
SME Internet connectivity
|
What are possible ways enterprises can connect to the Internet ? How do specifically Small and Medium Enterprises can connect to Internet Is the Enterprise have to always use the BGP Peering with Internet Service Providers ? If not how above thing is achieved?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjg5flr"
],
"text": [
"\\ > What are possible ways enterprises can connect to the Internet ? you connect through an ISP. \\ > How do specifically Small and Medium Enterprises can connect to Internet buy purchasing a fiber optic connection from an ISP. \\ > Is the Enterprise have to always use the BGP Peering with Internet Service Providers ? since you're connecting through an ISP, you don't have to worry about BGP."
],
"score": [
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
fdallz
|
Google search working
|
How google is able to understand everything I type even it has spelling mistakes. Whenever I type something in browser i see that each word will be seperated by a '+' what is the significance of that?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjg7kdm"
],
"text": [
"> How google is able to understand everything I type even it has spelling mistakes. Basically Google creates lots of large dictionaries with lots of words. Because Google constantly crawls the web to find new pages, it can see how popular every word is, so it can easily see if you entered an unpopular word, and check if there's a similar word that is much more popular. > Whenever I type something in browser i see that each word will be seperated by a '+' what is the significance of that? The URL specification doesn't allow URLs to contain spaces, as well as certain other characters. Browsers and servers use \"url encoding\" which replaces these characters with other, allowed characters. Most of these characters are encoded with [percent encoding]( URL_0 ), and as such a space can be encoded with %20, but space was given a special encoding '+' because it is so common (if you want an actual plus sign you need to encode it as %2B)."
],
"score": [
5
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Percent-encoding"
]
]
}
|
[
"url"
] |
[
"url"
] |
fdb6yt
|
graphics processing unit
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjg9xco"
],
"text": [
"> How does a graphics card work? Graphics cards, like any modern electronic processor, uses interlinked transistors (devices that lets electricity from one side pass through unless electricity is arriving from another side) to do basic arithmetic *really really quickly* in whatever way they're told to do by their programming. The difference between a GPU and a CPU is generally that a GPU will be slower but able to do more calculations at the same time, though this difference is shrinking every year."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdbhvi
|
How did mining work back in the day? Did people just picaxe long tunnels into the rock hoping they’ll find something useful?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjgbby4",
"fjgbhwm",
"fjgc38c",
"fjggkoe"
],
"text": [
"Yes and no. Depending on what's being mined. Typically they'd find a vein and surface level evidence. (Think of gold washed down a creek, it comes from a vein somewhere)",
"Historically, prospecting involved thoroughly searching a wide area looking for mineral deposits on the surface. The best places to look were creeklines or ridges/hills, and any mineral deposits signified that there was likely more beneath the surface. The Romans used aquaducts for hydrolic mining, where they'd basically use a ton of water to wash away the soil to expose the rock and any veins of metal. The first mines were largely for stone, and required less precise methods to locate good areas to mine.",
"It depends a bit on how long ago \"back in the day\" is. For the mines I've visited here in Norway that's around the 1600s. At that time, the mining was mostly accomplished with heat (wood fires) to make the rock brittle and manual picks or chisels. Using fires to heat the rock and then flash-cooling with water can also break rock faces apart. As chemistry advanced and explosives became cheaper and safer, they gradually took over. Mining was a craft and geological experts were used to survey the mine and identify where to dig in what direction. Norway largely imported these experts from Germany and France, and you can still see some evidence of this foreign influence in for instance street names in [Røros]( URL_0 ).",
"Before modern methods of geology, finding ore in the rock was often a matter of luck. The ore might have shown itself on the exposed surface, or it might wash out and deposit on the surface. If they found a large ore deposit, they could follow the ore veins deep into the rock. By the way, pickaxes we know today aren't a typical mining tool, they're more for breaking heavy dirt and rock on the surface. Instead, they used hammers and chisels in order to be able to get highly precise strikes on the same spot over and over. That's why you can still see [this logo]( URL_0 ) on the coat of arms of many historical mining towns in Europe."
],
"score": [
26,
13,
8,
5
],
"text_urls": [
[],
[],
[
"https://en.wikipedia.org/wiki/R%C3%B8ros"
],
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Schlaegel_und_Eisen_nach_DIN_21800.svg/800px-Schlaegel_und_Eisen_nach_DIN_21800.svg.png"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdbvmm
|
Computer Science vs Computer Information Science
|
I cannot decide which one to take in college. Help
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjhbe5w"
],
"text": [
"In practical terms, CS is the more technical version of the degree. It is usually taught through the engineering school and will include a lot of science, math, and electronics requirements. It will have a focus on building programming skills and include a lot of computer theory. Someone with a CS degree will know how a computer works from electrons on up and have the skills to create novel computer components. A CIS degree is more about how to make computers do things. It is usually taught through the business or arts and sciences schools and will have broader general requirements in those schools at the expense of computer-specific courses. There will be less emphasis on programming and theory, and more on building and managing computer systems build from off the shelf components."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fdc0xv
|
What would happen if you filled an HD or SSD to the last byte? Would it stop the pc from functioning?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjgeeci"
],
"text": [
"Yes. Modern operating systems like Windows use a portion of your hard drive to store some temporary files it needs to function. It may also use your disk as extra memory if your onboard memory gets over utilized. For this reason, there has to be some space available for these temporary files. Windows for sure (other OSs too, probably) has some alerting that is built in to start warning you when your space is getting low. You can change when this occurs in the performance/alerts section, but I believe the default is 10% remaining. Continuing to fill up your disk space will result in gradual increases in performances issues until your computer is pretty much unusable and it becomes difficult to even delete files to free up space as even the act of deleting files takes up some temporary space."
],
"score": [
30
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdei77
|
Why does the temperature of some showers switch from freezing cold to scalding hot with only a slight nudge on the handle?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjh114b",
"fjgwfj1",
"fjh290l",
"fjh8v5h",
"fjh85t3",
"fjhcxfl",
"fjhd5b1"
],
"text": [
"Also, your shower makes warm water by mixing hot and cold water. If the hot water is too hot, than the temperature of the warm water is more sensitive to slight changes in the mixture. If you decrease the temperature of your hot water, you will have better control over the warm water.",
"All cartridges (the box housing the control valves) are different. The age of the cartridge, the condition of the valves, and even proximity to the water heater play a role.",
"I had an old shower that did this. The hot and cold mixed in the shower head itself, and part of the problem was that there was dirt in the showerhead. Cleaned it out, and the water mixed more gradually after that. This sometimes happens when older pipes get worked on and dirt or calcium dislodges from the inside of the pipes.",
"Lots of variables at play. The way most showers work is by mixing hot and cold. The water on your \"hot\" side is likely very hot so a small increase in that water probably shoots up the average temperature of the mix by a lot. I'm also willing to bet that unless your shower is brand new, the handle is not easy to move by a TINY bit. Anytime you move it, it jumps so it's hard to control. Theoretically the water temperature on the hot side shouldn't matter if you have fine enough control. But it probably moves too much so a lot more hot water comes out. Decreasing your water heater temperature might make this more gradual. Keep in mind, this will also make it so you have less shower time before the hot water is out. (It will take more \"less hot\" water to do the same amount of work as less \"very hot\" water).",
"It’s about time for a new innovation. I’ve wondered if ball bearings could reduce the nudge particularly in the middle mixing section of the handle’s turning circumference.",
"With instant/tankless boilers sometimes that little nudge can decrease/increase the pressure of the water enough so the boiler turns off or on and that's how it jumps from freezing to super warm and vice-versa. Usually a little water pump fixes this issue and you can have more range in terms of temperatures.",
"Thermostatic temperature control, or balancing spool, or both. It's a safety feature that, say someone flushes a toilet, a piston heats up and slides allowing more cold water in to compensate rather than scald. When they get old their mechanism is loose and slides too easily or too quickly. This is often caused by water heaters set too high. 120 minimum (to prevent bacterial growth), 140 maximum to prevent scalding and wearing of plumbing components. They're fairly easy to replace, water has to be shut off from the fixture (typically to the whole house), YouTube will show you how to get it apart rarely needing anything more than a screwdriver and pliars, and Home Depot or similar sell the replacement cartridge for about $30. Consult r/plumbing if you need more help."
],
"score": [
118,
52,
39,
15,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdk2no
|
Pull Down Resistors
|
Hey r/explainlikeimfive could someone explain to me how a pull down voltage circuit works? I tried googling it but I can't make sense of the answers I'm getting. Thank you in advance!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjhzwko",
"fji0qz1"
],
"text": [
"To use the analogy of water flowing in pipes, a pull down resistor would be like having a tiny pipe that empties into a drain attached to a larger one. If water is flowing in the large pipe, sure some escapes down the tiny pipe, but most goes where the big pipe goes because it is easier. If the big pipe stops flowing, like from closing a valve somewhere, the little pipe will empty the big one of water because no new water is coming in. Expanding on this a little, there are also pull-up resistor circuits that work the opposite way keeping the big pipe full of water (at some voltage potential) if it isn't allowed to drain.",
"The super simple answer: A pull down (or a pull up) resistor is a way to set a \"default\" voltage on a pin/wire when nothing else in the circuit is trying to impose a voltage on it. A pull down resistor defaults the pin to the low/ground state. An example: Lets say you have an output on a microchip that in the \"on\" looks like a 50-ohm resistor connected to 5V, and in the \"off\" state looks like a 50,000,000-ohm resistor connected to 5V. Now what you really want is when the output is \"on\" that it has ~5V on it, and when it's \"off\" it's at ground. So what you do is put in a decent sized (say 50,000 ohm) resistor that connects that pin to ground (i.e. it's a resistor that \"pulls down\" the voltage if the only inputs on a line are very high resistance). So in the on state you have: 5V - (50 ohm) - pin - (50,000 ohm) - ground. Which means the pin will end up very close to 5V. On the \"off\" state you will have: 5V - (50,000,000 ohm) - pin - (50,000 ohm) - ground Which would mean the pin is very close to ground."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fdphyo
|
Why does the lint collection that I pull out of the dryer always look like a greyish purple color?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjj2ryz",
"fjjbvb5"
],
"text": [
"If you literally put in only white clothes and get purple lint, you may have a fuzzy purple sock that slipped the gasket and is hiding in the casing. This sounds more like an electrician visit than a ELI5",
"You are collecting fuzz off the many clothes and materials you dry, all shedding, all contributing. The lint collection in the dryer lint collector is the color average of your personal taste, which is pretty awesome when you think about it. If you just liked red, the fuzz would be red. But you enjoy all sorts of colors, so they combine to create a sorta gray lint. Since it has a purple tinge you probably prefer cool colors. I do too."
],
"score": [
13,
9
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdpoy6
|
How is video footage shot in 30 frames per second much cleaner than computer recordings shot at 30 frames per second?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjj9czs",
"fjjpd72"
],
"text": [
"Computer generated frames usually show no motion blur; it's as if they have an infinitely short shutter speed. Moving objects in a shot will jump position from one frame to the next. Real-world photography has longish shutter speeds which mean that moving objects have motion blur and this greatly reduces jumpiness at low frame rates. Traditionally the shutter angle is 180 & deg; which (since 180 & deg; is half of a circle) means the shutter speed is half the duration of a frame, e.g., 30fps footage would have a shutter speed of 1/60th of second.",
"Simple: **motion blur**. Motion blur is \"automatic\" and \"free\" in analogic video footage, but costs a lot of computation to simulate in a computer animation, and is usually not done. This is why 24 FpS was perfectly good for decades and decades of movies, but 30 FpS was never quite enough for action games."
],
"score": [
9,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdr7z8
|
how are the photos from the rover so clear?
|
The new pictures from the mars rover are incredible, but I would think the camera lenses would be filthy due to the wind and dirt. Obviously, there’s no one there to wipe the stuff away, so how are the photos so clear?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjjgs0y"
],
"text": [
"The atmosphere on Mars is less than 1% as thick as Earth's, so yes, there's wind, but even a 60mph wind on Mars has the same amount of force as a gentle breeze. The wind can only pick up the tiniest particles. It's just as likely to clean the camera than to deposit dust on it. There's also no grease or moisture or macroscopic dirt that can make the camera dirty, just extremely fine dust that gets blown off very easily. Almost all of the cameras are either pointed slightly downward or are steerable so they can point in any direction to avoid dust accumulation."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fds9gb
|
Why can spell check guess what I mean on obscure words that I'm not even close on but then with common words that I'm only a single letter off on it will have no suggestions?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjjnkmz"
],
"text": [
"Two reasons. 1. Obscure words are commonly misspelled, so the computer calculates that those are more likely to be misspelled. They also tend to be butchered in pretty consistent ways. common words are less likely to be misspelled and theres are lot of ways of being just one letter off. 2. For more sophisticated spell checks, less common words have more specific contexts in which they are used, which common words are hard to pin down by context."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fdxmui
|
why do cribs get recalled all the time?
|
How hard is it to make a safe bed for a baby? Why do manufacturers not know how to do this by now??
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjkhliz",
"fjkhdag",
"fjl1gm1",
"fjkjvet",
"fjkkoeq",
"fjlsurv"
],
"text": [
"It's easy to make a safe crib. Take hard, dense wood, shape it to fit snuggly, and use high quality fasteners. The problem is that this is expensive. Given the choice, most people will buy the cheaper option if the product performs the same function. To chase sales, companies have to find ways to make things cheaper. So companies try to reduce the cost of their products with cheaper materials and labor so they are barely functional. This generates the most profit (cheaper = more people buy it over expensive options and they make more money per sold piece). Often times, this sacrifices safety because they didn't need to test for it (no regulations) or they didn't want to test for it due to cost. For more unscrupulous companies, recalls cost less than the lost profit if they didn't make the product.",
"Usually because the dimensions between parts (a rail and a mattress for example) can, in rare instances, cause an infant to get caught or suffocate. Decades ago, there were many recalls because of really dangerous designs like latches that are easily opened or will allow a rail to fall on a baby or pinch their fingers.",
"Former news producer here. One issue is you likely just hear about cribs getting recalled a lot more often than the thousands of other products that get recalled all the time. The only time we put recalls in our newscast is if it was particularly spooky, things involving food, babies and medicine are top of the list. New mothers get scared about anything that could harm their baby, share it all over Facebook, then you hear about it.",
"In many cases, the issue was convenience vs safety. Most cribs have an adjustable mattress height. For tiny infants that barely move, you can keep the mattress high so it's easy to reach them. But when they get to around 9 months and they can pull up and try to crawl over the side, you have to lower the mattress. The problem is, in order to lower the mattress enough that the baby can't escape, it's now so low that many adults can't easily reach the baby - especially if the baby is squirming and doesn't want to come out of the crib. One solution was the drop-side crib - one of the sides could slide down to make it easy to reach the baby. Unfortunately it was extremely hard to build a mechanism like that and also make it 100% foolproof. [ URL_0 ]( URL_0 ) That wasn't the only solution. Dozens of other types of cribs had mechanisms to make things more convenient for parents that compromised safety.",
"Also, some defects only become apparent after years of wear and tear, but would still result in liability to the company. New safety standards might also force the recall of certain older models.",
"For everybody saying that making a safe crib costs money, that's not really the case. Making a crib that is suitable for safe sleep for infants is actually incredibly easy and cheap to do. All it's all the extra shit costs money, and presents issues. Infants need a flat surface, with a semi-firm mattress, and some walls. It needs to not easily tip over. That's literally it. It's all the extra options that present issues, like trying to make it convert into a toddler bed, have a mobile hanging from it, drop down sides, etc. Those things can present safety issues. These companies spend lots of time on these things, because it appeals to parents. Having these features makes parents feel like they are getting the \"best\" for their baby. But it's really just added cost and possibly even less safe. A thin mattress in a cardboard box is likely as safe as most popular cribs. Many babies in Finland sleep in government issued boxes, and they don't have problems with SIDS. tl;dr Cribs are easy and cheap to make. Recalls are usually because of overcomplicated bullshit that was added to market toward anxious parents."
],
"score": [
67,
30,
8,
8,
5,
4
],
"text_urls": [
[],
[],
[],
[
"https://www.verywellfamily.com/drop-side-crib-safety-issues-294016"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fe1js6
|
How does RAM work and what is it’s purpose?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjl5pz7",
"fjl61bt"
],
"text": [
"I think of RAM as similar as short term memory in humans. Its the little things that you access on a frequent basis that are stored there, but also things that are stored there can be erased if it no longer used.",
"I always understood RAM like being the desk you work on. The more you desk is big, the most you can do in a same time. You'll need longer time to draw an architectural plan in A2 on a nightstand."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
feigd1
|
Why does connecting to a wifi take so long while connecting with mobile data is basically instant?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjo7cxz"
],
"text": [
"Mobile is essentially an always on technology. Typically when connecting to WiFi you need to authenticate, get a dhcp address, etc... which can take a bit of time."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
feik4e
|
What does return do in programming?
|
Primarily python
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjo92po",
"fjog7p3",
"fjo8x18"
],
"text": [
"It tells the program to leave the current subroutine (i.e. method or function) and 'return' to the calling address. You can also return a particular value, which can then be stored in some variable at the place the function was called. For example, lets create a function: #function that takes a number \"num\" as a parameter function addOneToNum(num): num = num + 1 #add 1 to our number return num #return our number & nbsp; & nbsp; Now, lets call that function and store the value it returns in a variable: var number = 0 #create number print(number) #will print \"0\" number = addOneToNum(number) #Calls our function and places #the returned value in \"number\" var print(number) #will print \"1\" & nbsp; & nbsp; Edit: You can also just return without a value: function printHello(): print(\"Hello!\") #print \"Hello\" return #return to call print(\"Folks!\") #this is never reached, because we returned to the calling address already printHello() #call function, which is then returned here print(\"Goodbye\") The above will output \"Hello! Goodbye!\". URL_0 has some pretty good basic tutorials. The [Python Functions document]( URL_1 ) has some examples about return and return values.",
"In Monopoly, you pull the card that says \"go directly to jail. Do not pass go, do not collect $200 dollars.\" You are instantly transported to another section of the gameboard and then follow the rules surrounding your transportation. You were \"return\"ed to jail.",
"It sends control of the program back to what called it and frees that memory space up. So when you call a function with a parameter, especially ones that are stored outside of your mainline, you need to return control back when you exit so that you can take advantage of the memory space"
],
"score": [
9,
5,
3
],
"text_urls": [
[
"https://www.w3schools.com/python/default.asp",
"https://www.w3schools.com/python/python_functions.asp"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fek9on
|
Why do computer monitors go a bit weird when you touch them?
|
When I touch my monitor, it starts pulsing dark circles around the spot where my finger is. Why does that happen?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjoknv5",
"fjpcfzs",
"fjp92sm",
"fjpbayq",
"fjq763l",
"fjpffq8"
],
"text": [
"Your screen is composed of multiple layers of material. One of these layers is a grid of liquid crystals (the LC in LCD). Pressing on them deforms them, changing the way they transmit light. Hitting them with electricity also deforms them, which is how they go from opaque to transparent and anything in between.",
"The LC in LCD stands for Liquid Crystals. You can think of them kind of like water in a video game. They flow like a liquid, but they follow predictable patterns. The ones in your monitor are special in that they change their patterns when there is an electric current. So you can make them clear like water, or opaque like coffee. It turns out this is pretty useful! Let's say you shine a light toward a piece of paper with three holes that have red, green, and blue filters. If you block all but the red one, the light will be red. If you do it with all but the blue one you'll get blue light. You can also mix and match colors to make all sorts of different colors. Blocking the holes manually takes a lot of time, but by using liquid crystals you can do it very quickly. By putting a layer of liquid crystals between the light and the holes with colored filters, you can let as much, or as little, light through as you need. So you can mix a little red, some blue, and a lot of green, or anything any between. And you can this very quickly. If you take millions of these and make them very small, you basically have a monitor. Since liquid crystals behave a lot like liquids, if you put pressure on them they will flow. That will change how the light passes through it which causes distortions. Much like how ripples on a pond makes the bottom look weird.",
"Patient: Doctor it hurt when I do this. Doctor: Stop doing that But seriously it's due to polarization in LCD screens. When certain types of plastic are under stress, cross-polarized light (which is how an LCD makes bright pixels turn dark) will create weird rainbows and other effects.",
"This depends on which type of screen you have. There are LCD screens, or Liquid Crystal Display, where pushing on the screen pushes these crystals around, similar to how water moves in a plastic bag when you push on the water. There are also OLED, which has a carbon layer, another substance, sandwiched between two electrodes, or basically a conductor. When electricity flows through this sandwich, it will emit light. Pressing on an OLED screen will not distort the image unless you are putting excessive force.",
"I'm seeing a lot of answers a five-year-old couldn't understand. The picture is made of many of little clear boxes. These boxes can turn. How the boxes are turned changes the color of light coming through them. Your computer makes the picture by telling each box how to turn. Your computer doesn't know if the boxes are doing what it says. When you touch the screen, you turn the boxes so the light comes out looking black. Edit: this is also the way I'd explain it to my mother.",
"The LCD uses liquid crystals. There's two layers that matter - the back and the front. The back filters all the light that's not polarized in a certain way (vibrating up and down or left and right), and the top filters all the light that's 90* of that. So normally, no light makes it through. The liquid crystals line up in a helix when an electric field is applied, and that twists the light from up and down to left and right. If the layer is too thin, it won't twist enough and not enough light gets through. It's really hard to make some kind of spacer that would work, so what displays actually do is just mix a bunch of tiny glass beads into the liquid crystal solution. This keeps the display spaced perfectly. When you press your finger on it, you're squishing the layers together, squeezing the beads out of the way, and ensuring the liquid crystal is too thin or too thick to twist the light far enough. When you let go, everything springs back to normal."
],
"score": [
4614,
424,
183,
82,
8,
6
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fekxlt
|
How does in vivo gene editing work?
|
Like, how do the genes actually change, and how do you make sure you are only changing the right thing?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjopsid",
"fjotf15"
],
"text": [
"It's very hard to ELI5 this topic. So the basic principle is editing to insert some DNA (micro injection) or virally deliver it or just deliver some machinery for genomic editing into the zygote or the embryonic stem cells. You would get a chimera because some of these initial cells of the animal have the Edit and some don't. And then it's a gamble for whether the edit makes it to the germ line (sperms and eggs). If they are in the germ line, you breed the mouse with another and you keep breeding till you have a homozygous or heterozygous mouse for the gene you edited. There are many many ways to edit the actual genome, I'll list a few. Most modern approach is CRISPR, where you can literally use a customized enzyme to go and edit the DNA. You can also use gene targeting methods to generate a mouse with a knocked out gene that can be bred to make a mouse line with basic strategies. These could either be the good old homologous recombination techniques that are not so efficient because they take quite some effort to get to work, or they use designer enzymes like Zinc Finger Proteases or TALENS (this is good but takes some effort too, so weeks to a few months). You can also use the amazing Cre LoxP system, where you use transgenic techniques to insert two sequences called LoxP around the gene you wanna remove. Then in another mouse, insert the gene coding for Cre recombinase (an enzyme) with some promoter differences and/or an estrogen receptor fused to make it expressed in whichever tissue you want and at whatever developmental stage you want and then breed the two mice. The pups will have cre and LoxP, and whenever cre is expressed in a cell, it'll find the LoxP sequences and just remove the gene between them. If you have an estrogen receptor on the Cre, you can also not allow this to happen unless you give the mouse tamoxifen, synthetic estrogen, to allow the enzyme to do its job. I mean there's literally dozens of methods, but CRISPR beats them all. Now to address the specificity issue.. Well if you want to just overexpress a gene (like add more copies of it) that's easy, you don't care where the gene is as long as it's not disturbing other genes and is in a good spot that is accessible for transcription (lots of trial and error here). But if you want to delete or edit that's hard, and that's where you use things like CRISPR, where you embed a sequence homoglous (the guide part) to where you want to insert your gene, and so it sort of finds right place. I know for a fact my explanation was a bit technical, so I apologize in advance. But I am ready to clarify anything you don't understand.",
"Genes is how we call specific parts of a cell's DNA that hold some useful instructions, usually the instruction to build a particular protein. DNA is a long molecule made up of a sequence of 4 smaller molecules whose names we abbreviate A, T, G, C. You can picture it like a long piece of string with a bunch of beads that come in four possible colors. The combination of colors in a specific order is a code, which the cell can decipher to get useful instructions. Kinda like we can encode the word \"SOS\" in Morse code as \"...---...\". In general, genes tend to span several thousands of \"beads\". & #x200B; Cells and viruses have evolved many proteins to modify DNA, either by replacing individual beads or by changing long stretches of beads at a time. For example, due to accidents beads can crack or their color fades so that the cell can no longer tell what it used to be. They then take their best guess and replace the defective bead with a new one. If they made a mistake, this might change the meaning of the code, which affects the gene. It's a mutation! Mutations can have no effect, positive effect (e.g. more efficient instructions), or negative effects (e.g. instructions unclear, cell harms itself). & #x200B; The tools that cells use to change DNA can be harnessed by scientists to edit genes in a targeted manner. One tool you may have heard in the news is \"CRISPR\", which comes from the immune system of bacteria. The CRISPR system uses a small \"guide\" string of beads to direct a protein called \"Cas\" to a spot in the DNA with the same sequence of colors as the guide. Once it found a match, the Cas cuts the cell's DNA! Cuts in the DNA can spell death, so the cell frantically scrambles to fix them. In the process it may lose some beads or add some extra beads in by mistake. If you provide a \"repair template\" - a longer string that looks like it might fit into the cut spot - the cell may try to put that in as well. So by using CRISPR and providing as a repair template a non-mutated healthy gene, you could potentially replace a gene with a negative mutation. In the case of CRISPR, finding the correct place to cut depends on the sequence of beads on the guide string you provide. Though it sounds pretty simple, there's lots of room for error: Just like you will sometimes misspell words, the guide string may match to a slightly different sequence, which results in the wrong part of DNA being cut open. This is what is called an \"off-target\", and is something that the scientific community is trying to reduce by improving the CRISPR system."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fenza9
|
How do fiber optic cables work in terms of data transmission?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjp96s3"
],
"text": [
"Light on = 1 light off =0 other than it being light and not electricity it works the same as copper cabling"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
feouy7
|
How come when you take a picture of a screen (like a computer monitor), the picture of the screen comes out with black lines and static?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjpfb9c",
"fjpfdcc",
"fjpfsky"
],
"text": [
"Get up really close to your monitor and youll see its actually a webbing of dots - old tv's were more obvious - blue, green and red dots. Your eyes fill the blanks in between to make it a clear image - but the camera sees the dots.",
"Computer monitors are constantly updating their image, they're just doing it faster than we are able to see. The camera shutter is faster than the human eye, though, so it can see the areas where the monitor was refreshing right that instant.",
"There are a couple factors that make photographing different types of screens difficult. When photographing CRT screens like old computer monitors and television sets, sometimes the shutter speed of the camera can be out of sync with the refresh rate of the screen in such a way that a giant band appears across the screen because you're literally capturing the screen in the middle of a refresh pass (which is invisible to the human eye). See [this photo for an example]( URL_0 ). The problem with modern displays, flat screens like LCDs and related technology, is that the screen is a grid of pixels and the CMOS censor of the digital camera is *also* a grid of sensors... and *weird shit* happens when those two grids duke it out. That weird shit is called the \"moire effect\". [This YouTube video]( URL_1 ) shows a simple demonstration of the effect in action. I think this is the \"black lines and static\" you're talking about: the effects of the moire pattern."
],
"score": [
5,
3,
3
],
"text_urls": [
[],
[],
[
"https://www.blurbusters.com/wp-content/uploads/2017/05/VSYNC.png",
"https://www.youtube.com/watch?v=6I0SF0dXoZg"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
feqkqj
|
Why is that a Bluray can’t remember where I was in a movie, but older tech like a DVD can?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjpqjt0"
],
"text": [
"VCRs can too XD It probably different player to player. I think mine will resume, but not sure."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
feteh3
|
Why do the printer cartridges move from right to left when you switch on the printer?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjqqnca",
"fjqqt1k",
"fjqvacd"
],
"text": [
"The printer is checking that the carriage is operating properly then \"homing\" it (setting it to a known zero reference point).",
"It's a check-up of printing system. The printer check If there are any problema with motors and other stuffs.",
"The printer wants to know where its cartridge is, so it knows where to start printing from. If you pulled the plug mid-print last time, the cartridge would be abandoned half-way across the carriage. If it just started printing from there, where you think the top left bit of image is, would instead start being printed in the top middle of the page. So the printer moves its cartridges and finds where the zero-point is and does some other self-checks to make sure things are moving as they should."
],
"score": [
7,
4,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
feul4o
|
How does my iPhone Face ID still recognize me even after I grew a beard and wear sunglasses? How does it know I’m not an imposter in disguise?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjrfnp2",
"fjsfvmm",
"fjsj30s",
"fjrfsy9"
],
"text": [
"the ai measures the distances between features of your face e.g nose width, distances between brows, your brow ridges, forehead length, chin length all relative to other features. sunglasses and beard wont change any of that. try prosthetic makeup.",
"When Apple announced FaceID with the iPhone X, they explained that it would track changes to your face over time so that something like growing a beard would not affect performance of the feature. I’m guessing that they also trained the system to understand what glasses look like and ignore them when scanning.",
"And here I am trying not to be insulted when my iPhone doesn't recognize me immediately after I wake up.",
"There are all sorts of facial recognition algorithms out there, but they mostly all rely on certain key aspects of your facial geometry. A common one is the distance between your eyes, or the distance from one eye to the bridge of your nose. Others include the width of your nose, or the distance from your upper eyelid to your lower eyelid. The algorithms are designed to be tolerant of things like glasses or changes in facial hair. Interestingly, there are [makeup and hair styles designed to defeat facial recognition]( URL_0 ). You'll notice that they tend to block an eye or the nose, add bumps to the face, and/or make the face seriously asymmetric."
],
"score": [
17,
7,
5,
3
],
"text_urls": [
[],
[],
[],
[
"https://cvdazzle.com/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
fext5h
|
How do emails know where to go?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjsvusc"
],
"text": [
"DNS (Domain Name Service) is mainly used to translate domain names (\"[ URL_0 ](https:// URL_0 /)\") into IP addresses ([151.101.129.140]( URL_2 )), it also contains so-called MX records (Mail eXchange records) that contain information about which server is supposed to receive mail for addresses that end in @ URL_0 . Then, when you log into your Google Mail account and type a mail to someone with a \"[ URL_0 ](https:// URL_0 )\" mail address, the Google server checks the DNS for URL_0 , finds out the IP address in the MX record for Reddit, and then connects to that server and says \"Hey, I'm the mail server for @gmail.com and my user party\\_in\\_my\\_head just sent this mail for `someone` @ URL_0 , here it is\", and the reddit mail server then puts it into the recipient's mailbox."
],
"score": [
9
],
"text_urls": [
[
"reddit.com",
"https://reddit.com/",
"https://151.101.129.140/",
"https://reddit.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
ff3tzs
|
How do polygraph tests differentiate honest nervousness and deceptive answers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjvartw",
"fjw1sfo",
"fjvorvc",
"fjwzhq1",
"fjw9t9v",
"fjx1arf",
"fjx37at",
"fjwfnuh"
],
"text": [
"It can't. This is why they are not admissible in court. Polygraphs measure skin conductivity (sweat), heart rate, breathing, all of which are detectable signs of stress. There is no way to detect lies, and an individual can fool a polygraph by remaining entirely calm.",
"Like its cousin, the [Scientology E-Meter]( URL_0 ), the polygraph is a prop for an interrogation. Its purpose is to make the subject think that the interrogator can read their feelings, thereby making it feel useless to lie. The polygraph displays output that relates loosely to the subject's emotional state. It doesn't tell whether you are lying. It tells whether your skin sweat and oil are changing, which has to do loosely with being nervous or excited or horny or needing to go to the bathroom or a whole bunch of other things. But people are really good at thinking that things are more strongly connected than they really are. If you were to try deliberately to get a signal out of a polygraph or e-meter, by tensing your muscles or thinking about something shameful *(your brother's underwear?!)*, you would see that it did give a signal! But that signal doesn't mean \"lie\". It means \"change\". And that is what makes it an effective prop. It is more impressive than a machine that just randomly goes \"ping\", because it does relate to *something* that's *somehow* connected to the subject's thoughts. And so it is a prop that constantly conveys, \"I know what you really think, I know what you really did, your body tells me things that your lips are not willing to admit. The output of this machine is your real truth, and it is already on your permanent record. You may as well do the thing that will make that record look acceptable.\" (If the interrogator used a gun instead of a polygraph, it could still be a prop, but would convey, \"Your life is in my hands, I can kill you if you displease me.\" That's a technique some interrogators use sometimes, usually to extract false confessions for political purposes; but it's not the same one that the polygraph is used for.)",
"Incredibly poorly. If you're nervous you're going to fail a \"lie-detector\" test. They're not admissible as evidence in court because they're so unreliable, but confessions made by people who don't know that can still be used to convict.",
"They don't polygraphs are a psuedo science at best and can not detect lies, even the person who invented them regrets doing so since they don't actually work like he thought",
"Thanks, y’all. I’m very into the true crime rerun channels and the polygraph is used every now and then during interrogations. Now that I think about it, it’s not used that much. I can definitely understand how it is a tool to coerce rather than to prove.",
"They can’t so if you’re ever in a situation where cops ask you to take one, DONT. Ask if you’re under arrest, if not, leave, if yes, ask for a lawyer and don’t say anything till they get there. Guilty or innocent you don’t say shit.",
"I've taken a polygraph twice. Failed both due to extreme anxiety. Basically, they lie to you about their effectiveness. Following the test, both tried to get me to confess to the crime in question, pulling the \"do the right thing\" card. If you're in a situation where the outcome determines your level of freedom, then you know they only have the prosecution's interests in mind. They're designed to coerce confessions. There is no detectable difference between a lie and nervousness. They aren't admissible in court unless you agree to it.",
"Polygraph tests are very inaccurate. They don't differentiate honest nervousness and deceptive answers very well at all. Their most powerful use is the reactionaries people have when invited to take one. If people believe they work, then the their reaction to being told to take one speaks volumes. They are inadmissible in court because they are only slightly more accurate than just guessing whether someone is lying."
],
"score": [
280,
47,
13,
9,
6,
4,
4,
3
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/E-meter"
],
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ff71xk
|
Why does the moon look waaay smaller on the camera than it does by naked eyes? Whereas people look bigger on the same camera (smaller focal length)
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjwnjuq"
],
"text": [
"Well basically because your eyes are amazing. They automatically adjust for focal length and for exposure. Camera sensors and lenses are really far behind but getting better. In the future you might be able to get a realistic looking image from a single photo. Some photographers are taking multiple photos and blending them to try to recreate what your eyes and brain are able to do, but that's really difficult."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ff765n
|
How do "I'm not a robot" ReCAPTCHAs know that I'm human with just one click of my mouse?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjwl1vp",
"fjwmgfx",
"fjwnxax",
"fjwl49e",
"fjwo5pf"
],
"text": [
"I read somewhere it is due to the website itself. It tracks the pattern you trace with the cursor. Robot would go straight to the box, but humans have small little deviations. I may be wrong though.",
"Google wont say exactly why to keep it harder to game by bots but it's a combination of the movement of the mouse, the overall way you interact with the page, and things like IP addresses and the analytics google collects on you that paint a picture of a real person. [source]( URL_0 )",
"Because as a human, you have to move the mouse/cursor to the box from wherever it was previously to click. In the movement, you have tiny itty bitty movements that destroy a straight line if you move the mouse there in a normal fashion. However, a robot/bot finds the elements of the clock box and skips the movement portion OR it inputs the commands to move the cursor in a way that appears that it’s (in computer sense) slowly moving the mouse there based off of coordinates. Now you’re saying “well I’m almost certain I’m human, why does it make me have to do the picture thing?” Simply because when the page loaded with the captcha, your cursor was already a given “close-ness” to the captcha. In this case, the captcha says “I’m not sure if you’re human or bot because I couldn’t track your mouse long enough, so to be safe, here’s some pictures” Also, it tracks as you move down a form to fill in the form. You can press TAB to move from field to field (like from first name to last name) OR move your mouse and click on each field to fill out. In the 2nd case, the captcha says “you didn’t move a mouse to fill out the form, here’s some pictures” Edit typo and added TAB explanation",
"The images are generated in a way that a robot can't see it. We see a bunch of dots closely gathered in a sea of dots that looks like an 8, or KjkvAg but the bots would just see something like \"IMAGE\" Or you know what a crosswalk looks like but the bot just knows there's 9 images.",
"Likely you are periodically asked to solve an ACTUAL captcha. I believe those responses when successful are cached for a time and reused so you don't have to do it EVERY time, only every week or two. ie if you've proven recently you are human from the same IP and the same login on the same website (or server?) you're off the hook for the next few times. & #x200B; I think that's the way that works."
],
"score": [
15,
13,
7,
3,
3
],
"text_urls": [
[],
[
"http://qnimate.com/how-does-googles-no-captcha-recaptcha-work/#Factors_on_which_Google_depends_to_detect_bots"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ff95ax
|
In terms of cyber security, what are the differences between Mac and PC?
|
My fiance has been watching the Jim Browning YouTube videos regarding the scammers overseas who use call centers. We were also watching ScammerRevolts who usually gets access to the scammers computers and deletes their files or syskeys them. It's been noted in both of the channels that some call centers use Macs and some use PC/Laptops. Is one more protected than the other?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjx0z4e",
"fjx0vyn",
"fjx463w",
"fjx4rw0",
"fjx6cmn"
],
"text": [
"It’s not that one is a whole lot better than the other but the reason you hear people say that macs don’t get viruses is because the people making the viruses have a lot more potential victims if they make it for windows since more people use windows",
"There is no security that can protect you from yourself. If it's your computer, you have administrative access, which means if the scammer can convince you to run a program, they can basically bend your computer over and slam it good and hard without even the common courtesy of a reach-around.",
"One has all the market share and thus has far far more effort put into exploiting it. The other costs twice as much.",
"For the most part, one is not more protected than the other. However, there are more PCs out there, and they are more likely to be used in business and finance. That makes them more of a target. If I am trying to find a new exploit, I'm going to look for one on the computer the banks use, not the one the musicians and artists use.",
"A few people mentioned more market share for PC's = bigger target.. while possibly part of the reason, another very real reason is the amount of commercial products for remote admin of the windows platform, and the number of commercial malware kits. But yes, if you install something on your computer for someone else, you don't own it any more. Your fault end of story, doesn't matter what Operating System (os) it runs."
],
"score": [
48,
23,
5,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
ff9vr8
|
Why GPU can has thousands of cores while CPU only has a few?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjx9h4w",
"fjxj1vn"
],
"text": [
"GPUs have a lot of cores that are very simple. CPUs have a few cores that are very sophisticated. Often it's not practical to split up the work to run on lots of simple cores, so CPUs are better. For example, one core can't make a decision based on what another core is doing, so if you have a long list of decisions, it has to happen on the same core.",
"A while back I saw an answer to this. CPUs are like university professors. Gpus like kindergardeners. If you want to solve complicated equations, you ask the professors. If you want to color 5000 squares in yellow, you ask the kindergardeners."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ffapm9
|
How does a bot on this website scan all comments continuously for keywords to find relevant comments to reply to?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjx9q5s"
],
"text": [
"Using reddit's API. See this link: URL_1 It contains the latest comments (which you can see when you go to URL_0 ) in a format that is compact and easily parsable by a computer program. Each entry in this page contains the actual content of the comment and various metadata, including when the comment was posted, who posted it, the original link to the comment, the comment and post's unique identifiers, and such. The bot can use the IDs to post a reply to the comment (again using the reddit API)."
],
"score": [
9
],
"text_urls": [
[
"https://www.reddit.com/r/all/comments/",
"https://api.reddit.com/r/all/comments/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
ffcreh
|
Why is that in some animation styles things that are animated are brighter than the static background?
|
As an example here's a clip. URL_0 At 20s you can clearly see what the background is and what are all the animated bits.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fjxmhig",
"fjxl5e5"
],
"text": [
"Oh I can begin an answer to this. In traditional hand animation, backgrounds are usually painted or drawn with a greater level of detail, because they presumably only need to be painted or drawn one time. The background is a separate piece of art than the character models. Characters, prop, and other moving items are drawn multiple times on multiple cellulose sheets, refered to as \"animation cels\", that are laid on top of the background image to provide a foreground. These cels may appear brighter because they sometimes lack the fine detail of the background, a static image. It's much simpler to draw the same character multiple times, so they tend to look simpler, with simpler brighter colors.",
"I noticed this rewatching a nineties cartoon called Gargoyles. Basically fixed background pieces were a different colour. So facing 10 bookshelves, one is a bit brighter than the others, and that was always the one that would fall. Sane with statues, walk sections, etc... I wager it's because the other background is static so it was animated 1 time. The bookshelf that falls is a seperate piece of the background and has been animated hundreds of times, in an era before colour correction technology was fast and cheap it was probably just easier to ignore, figuring old TVs and the size made it difficultfor a viewer to notice."
],
"score": [
20,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
ffsn1p
|
In regards to high end headphones, what does a higher ohm set mean compared to lower ohm sets and what are the differences in sound quality?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk0ksgd",
"fk0q18j"
],
"text": [
"A high impedance on a set of headphones generally just means it requires more power to drive them to an acceptable volume. Portable devices, walkmans, ipods, phones, will generally favour a lower impedance because they require less power. Old hifi gear, for example, tend to be built with higher impedances in mind, so using a modern set of low impedance earbuds on a hifi amp would probably mean you can barely nudge the volume off the zero stop before it'd be too loud to be tolerable. The main advantages of a high impedance in headphones, really are more about situations that you wouldn't encounter as a home user, or out and about. High impedance headphones are less affected by differences in output impedance on an amplifier, and you can connect a bunch of them to an output without overloading an amp. TL;DR: For home use or out and about, you'd be absolutely fine with low impedance ones. There's no reason for the average Joe to go searching out high impedance headphones. For most the only difference you'll note is that they're expensive, and you have to nudge the volume up a bit further. There are plenty of examples of very high end headphones that are low impedance.",
"Ohms are the measure of resistance in an electrical circuit. Basically, the higher the ohms, the harder it is for electricity to move through something. This goes for anything, not just headphones. You can wire things up in \"series\" (which means one item after another) or you can wire things up in \"parallel\" (so that there's a branch and electricity can flow through multiple items at the same time). It's much easier for electricity to flow through the system overall when things are wired in parallel. Back in the old days, when recording music you had multiple people (every member of the band, the producer, etc.) all hooking their headphones up to the same piece of equipment, which could overload the amp (electricity flowing too freely). Professionals used high-ohm headphones not because of sound quality, but just so they wouldn't overload the equipment. High-ohm headphones became associated with professionals so everyone figured that high-ohm meant quality. The association stuck, so headphone makers started making all their high-quality products as high-ohm and the other equipment manufacturers followed suit. High-end personal equipment (with only one output) was made to work with the high-ohm headphones. It doesn't have to be this way, it just is. As far as sound quality goes, it's not technically the ohms that make a difference. You can hook up a set of high-ohm headphones to a cheap, low-power amp and they should still make some sound. It just sounds weak and tinny because the headphones were designed with more power in mind. Conversely, low-ohm headphones on a powerful amp will get bloated and distorted pretty easily, and can damage the drivers. It's more about compatibility than anything else."
],
"score": [
84,
18
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ffsopa
|
Why did "window duplication" happen on older PC systems when programs got frozen?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk0clug"
],
"text": [
"The screen back then was a frame buffer so when a window was displayed it was stored as pixels in it. The result is that the hidden part of a window or desktop is not stored when not visible. This was done because of the low amount of memory you had in the system compared to the amount needed to store the display information. If you had a window and move it was back then the window or desktop behind it that har to redraw the now displayed space. So when you move a window it gets copied or I supposed redrawn when you move it and multiple copies are created. The OS then call the window or the part of the OS responsible for the desktop and tell it to redraw its a window. If the redraw does not happen fast enough you get a trail all drawn copies of the current window when you move it Today you draw it to a buffer that all the time or what a window is supposed to contain. The OS then uses features of the graphics card and mixes them all together so when it behind a window is always stored and can directly be displayed with help of hardware acceleration in the graphics card. this makes semitransparent windows possible in a way it was not in the past. If you have a monitor that is 1024x768 and 16 million colors you use 1024\\*768\\*3/1024/1024=2.24 megabyte for a buffer for the display. It does not sound a lot today but windows 95 had a min requirement of 4 MB and 8 MB was recommended. So to store visual information of each window was problematic because of the low amount of system memory Today with a 1080P display you only need 6MB for a complete screen. But memory today are in most cases 1000x larger than back in the win 95 days. So the windows design changes when computer have enough memory to store what is needed."
],
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9
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|
[
"url"
] |
[
"url"
] |
|
ffst65
|
How does Thermal Imaging work?
|
Technology
|
explainlikeimfive
|
{
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"fk0e8ea",
"fk12odj",
"fk10xkd",
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"text": [
"Heat sources emit electromagnetic radiation with a frequency respecting to their temperature. The visible spectrum of EM radiation ranges from red to violet. The sun's surface is about 5000 Kelvin hot and our eyes happen to see this light. Infrared means that the frequency of the EM radiation coming from an object is below the visible specrum due to lower temperature than the sun, anyway it can still be detected and it's frequency measured pretty accurately. But How do we get a picture we CAN see? Like digital cameras have light sensitive chips that render visible light directly to true red- green- and blue information in their memory, we can build a chip that detects light of lower frequency and renders it to any other colour and intensity value in real time. It's just a microchip doing real time calculus, mapping the gathered frequency and intensity information to another color map we can display and see.",
"To summarise in a genuinely simple ELI5-way: all objects with any heat at all emit infrared waves. Thermal imaging simply uses sensors/cameras that \"see\" infrared instead of visible light, and converts it to light we can see. Technically speaking, humans even emit visible light. It's just such a ridiculously tiny amount that you can't tell.",
"The analog value from the pixels detectors are converted to digital values, usually already in the chip. These digital values are going thought some calculation to correct for difference sensitivities in the pixels to get consistent values. So that a specific digital value always corresponds to the same temperature regardless of differences in pixels detectors. After this each value is mapped into palette that converts it to RGB that is displayed. The palette are usually selectable by the user. In addition to this there might also be some math converting the values to temperature if it is what you want. The detectors can be of different types. Very common today is bolometric detector elements. Each element are heated by the received radiation. And the change in resistance caused by this heating are measured. All this is made in real time. ( from somebody developing IR cameras at FLIR for 25 years )",
"Actual ELI5: When things get hot, they let out tiny invisible waves, These waves are captured by a special lens The waves then hit a tiny special component, and the material gets hotter When it heats up, its electrical resistance changes Each tiny special component corresponds to a pixel on the display The pixel just shows a unique colour for each resistance (/temperature) Put many pixels together, and you have a colourful picture of resistance/temperature values in the form of colour",
"Electromagnetic radiation is a wave-like physical phenomenon that takes different names depending of its frequency, i.e. how fast the wave oscillates. The radiation our eyes can detect we call it visible light. But radio waves, microwaves, x-rays, gamma rays, infrared and ultraviolet are all 'flavours' electromagnetic radiation of different ranges of frequency. Every object emits spontaneously radiation, most intensely on a certain frequency that grows as the temperature grows. That's why heated metal starts to glow read: at a certain point our eyes can pick up its 'thermal' radiation. Every room temperature object emits in a range of radiation called infrared that our eyes can't see. It's just 'before' the red color, that's the first we can see. If you build a detector, exactly like those of a regular camera, but tuned on the infrared instead of visible light, you can obtain a thermal picture. Then you convert it on a scale of visible colors on screen to make our human mind understand.",
"A microbolometer is used for most thermal cameras. This is a fancy name for an array of a large number of temperature sensors. Infrared radiation is emitted by hot objects. This causes the individual pixels in the microbolometer to warm up. The change in temperature is measured by an electronic circuit, in much the same fashion as a digital image sensor measures the change. This is displayed using a defined thermal \"palette\" - hotter colours usually appearing brighter or more yellow/red. Because the wavelength of the infrared light is much longer (8 to 13 micrometers compared to 450 to 700 nanometers - about twenty times larger) it is necessary to have much larger sensor pixels than an ordinary camera. The sensors also need to be kept apart from each other, so that they can produce an accurate image without the adjacent sensors causing too much interference. This means that thermal cameras generally have a low resolution. Most are under 160 x 120 pixels - which is about 400x less pixels than a smartphone camera (19.2Kpixels vs 8Mpixels). Some microbolometer sensors have cooling to reduce their sensitivity to changes in the environment. Other sensors use a shutter, which is made of metal, so its temperature can be measured easily by a separate sensor. This provides a calibration factor. The shutter needs to be put in front of the sensor periodically to measure the reference temperature and compensate for errors in the sensor. If you have heard a thermal imaging camera \"click\" and have the image update pause, this is because it is calibrating. More advanced thermal cameras have a continuously rotating shutter that means the image doesn't get updated. Other technologies are used for thermal imaging (old cameras often used vidicon tubes optimised for thermal applications) but microbolometers are how the majority of thermal imaging cameras function. Fun bonus fact: Because thermal imaging cameras are valuable in military operations, they are restricted to 9 Hz refresh rate (9 frames per second) for consumer applications. This is ostensibly intended to stop people using them for combat operations. Additional bonus fun fact: FLIR makes the most thermal imaging sensors and holds a patent on a thermal imager with more than 14 thermal imaging sensors in a row. To work around this patent, a competitor, Raytheon, deliberately disables every 13th thermal imaging pixel on their thermal imaging array. The missing pixels are replaced with estimates from the adjacent area. Patents like these shouldn't be granted, but it goes to show why when writing a patent application, you should consider how it will be worked around."
],
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35,
13,
6,
6,
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[],
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|
[
"url"
] |
[
"url"
] |
|
ffwp5t
|
Smart Band/Watch, how is it able to detect our heartbeat?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk0zeim"
],
"text": [
"it has a small light emiter and light detector, which can detect the ammount of light going in. when your heart is open your blood pressure is low then when it's closed, and when the blood pressure is lower it let's more light pass. light sensor detects those changes and with them calculates your heartbeat."
],
"score": [
4
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
ffwpa2
|
How does a food processor work differently than a blender?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk10ilu",
"fk21asp",
"fk1p5n2",
"fk2d4zp",
"fk2k2ul",
"fk2k7np",
"fk3g9dq",
"fk2vocm",
"fk2oddi",
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"text": [
"A food processor tends to have a much wider, flatter work bowl, which means that it is much better at getting larger amounts of food - particularly solid food - to a smaller-but-not-puree consistency. A blender, with its tall, narrow shape, would struggle to get an even consistency with non-liquid foods unless you take it all the way to slush. Could you get by with juse one? Sure, but having the right tool makes the job easier and the results better. Blenders are the right choice for some applications - particularly liquid ones - and food processors are the right choice for solid foods.",
"A processor has sharp blades for slicing or chopping food. A blender has blunt blades for smashing and liquefying food.",
"A food processor uses the blades to chop, with the material getting thrown outward by centrifugal force. A blender uses the narrow walls of the pitcher to force the material back into the blades, allowing for purées. Completely different goals.",
"Blender = liquify Food processor = chop You make a smoothie in a blender and coleslaw in a food processor.",
"Blenders are primarily for “liquids”. The blade needs liquid, whether oil, orange juice, or water, to get things spinning, usually it’s added first, then the solid stuff on top. A vita mix can make things silken smooth unlike a food pro. Example: putting eggs and oil in first to make aioli. A food processor literally chops food up, and you don’t always need liquid to get things going. Example: Parmesan cheese. Just get the blade spinning and throw pieces in.",
"A food processor gathers all the information and attempts to understand its contents before annihilating them, while a blender is less discriminatory.",
"Food processors goes “ruuuuuuuuuu” while blenders goes “reeeeeeeeeeee”. Blender faster, food processors slower.",
"1. A food processor usually has more power so can \"blend\" or mix more for longer- mix for example a dough in a blender, it will burn out and cut the power -or fuse if it's a cheap model and then cut your circuit if you do too much in it. Blenders are best for short sharp bursts for example, smoothies and soups but not for heavy going stuff or for any longer than a few seconds or a few minutes. 2. Food processors have more tools and can blend/chop/mix and get different texture results. Blenders tend to just do liquids or make things more liquidy (blenders can make cakes and bread mixtures and the tools mean it wont turn to liquid or puree or smoothie like with a blender) 3. Food processors can mix up more in terms of volume than blenders, generally speaking. 4. Food processors tend to have a longer life. 5. Blenders cost a lot less and are easier to clean!",
"The blades can also be mounted at the top instead of the bottom enabling you to process the food once instead of hundreds of times",
"Besides the shape, the motor tend to have less \"oomph\" on a blender. Sure, a few break ice, but not everyone. A food processor needs to handle the pressure of things like doing peanut butter, without extra oil, and without burning itself. They also tend to have very nice accesories & #x200B; Honestly, you can do everything you can do on a blender on a food processor afaik, so I wouldnt buy the two..Food processor+hand on/inmersion blender (mini pimer here in my country) is enough for me"
],
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5420,
709,
289,
64,
26,
20,
9,
6,
5,
5
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|
[
"url"
] |
[
"url"
] |
|
ffx0ag
|
How does Screen Mirroring/Casting works (Mobile Screen to TV)?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk13mq0"
],
"text": [
"No. You need a few things to cast. 1) An internet connection. You don't necessarily need mobile data. I cast from WiFi all the time. NOTE: if you are simply mirroring your phone, you don't necessarily need to connect out to the internet, but you need WiFi as a means of communication between the devices. 2) A cast-capable device. The information needs to be sent from somewhere, and the device needs to be able to cast. 3) A device that can be cast to. That I know of, few TVs can actual receive a cast alone. That is why Chromecast exists. It is a bridge device that works on smart TVs and regular TVs alike. The HDMI is just the means that modern TVs use to receive video and audio data from external devices. There probably are TVs out there than can be cast to without additional devices (I think Apple had one for a while, and Google has probably partnered with some as well), but most TVs don't have that tech built in. Also, most TVs can't interpret a WiFi Direct signal. Again, it is possible to do so, but the tech just isn't part of TVs because there are other more efficient ways of doing it."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ffzagq
|
How disconnected is a virtual machine from the physical machine?
|
I don't understand how it's possible for me to copy something on my physical machine and paste it into my virtual machine, or vice versa. I realize that this could entirely depend on the virtualization software as well as whatever systems are running on the virtual machine, but how does information get passed from the virtual to the physical machine in general? Does this affect the security of my virtual or physical machine?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk1g0qx",
"fk1kgj8"
],
"text": [
"Think of them as two separate machines on the same network. They may be running on the same hardware, but they are isolated and can only communicate over the network. Why can you copy and paste between two machines? Because the Remote Desktop Protocol (RDP) you are using to access the VM supports copy+paste functionality.",
"All of the information hits the host machine first, and the VM software decided whether it goes to the VM or the host. It allocates a section of the hard drive and memory for the VM, and sometimes even processor cores. It will also create a secondary network connection with its own IP address. A big part of its job is to decide what information goes to the VMs, and what goes to the host. In general, a VM doesn't make security for the host worse and sometimes can make it better. The VM is only allowed to talk to the VM software running on the host, so if something bad happens, only the VM is impacted. Usually. There have been vulnerabilities that allow a VM to gain unauthorized access to its host. But assuming that holds up, you can run questionable software on a VM you wouldn't want to run on the host."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
fg0bjc
|
why GREY letterbox would be used over black
|
I’ve noticed on some TVs, and Dish, have black __and__ **grey** letterboxes when changing the screen size format. I know purpose behind shows and films using a letterbox, I just don’t know why a grey LB would be used instead of black.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk1udv8"
],
"text": [
"Probably to lessen the effect of burn-in on some displays. If you were to watch a lot of 4:3 content on a 16:9 display, only the 4:3 pixels would be used and they'd wear out faster. Putting a neutral grey color in place of the black bars would hopefully even out the wear pattern so that when watching full-screen content brightness and color would be even across the screen. Some displays will also move the letterboxed or 4:3 content by a pixel or two up/down or left/right so that there won't be a hard line where the \"wear\" begins."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fg7npv
|
How different is digital zoom on a cell phone versus taking a picture and later cropping what would've been zoomed in to?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk318j7",
"fk31j3w"
],
"text": [
"With digital zoom you save some storage space as you don't have to store all the pixels you'll later crop out. Also you don't have to open the image in a separate app to crop it, it's ready to send/post online as soon as you shoot it.",
"In terms of the final image they are effectively the same thing. Digital zooming takes a small area of the sensor and blows that image up with a scaling algorithm to fit the camera's output frame size. So it's like if you cropped a photo, then took the cropped bit into photoshop and scaled it up."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fg9c9p
|
How do watermarks work, and what are they for?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk37nt9"
],
"text": [
"Watermarks on an image are typically a semitransparent logo or signature layered over the original image, typically a stock photo or a drawing, in order to prevent other people from taking the image and claiming it as their own."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fgfz7i
|
What constitutes "passive ordnance" in military terms?
|
Had someone include this on their resume and was curious since I could not find a definitive answer via web search. I gather it is "non-smart" munitions/bombs?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk4a0ik"
],
"text": [
"You are correct. Passive ordinance are projectiles that can't be controlled once launched or do not change trajectory mid flight. Example mortar shells. You calculate the trajectory, made adjustments, launch, get a radio report about the error, adjust your calculations, repeat."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fghagj
|
How does a car like Koenigsegg Agera make more than a 1000hp with just a twin-turbo V8 whereas the Bugatti Veyron required a quad-turbo W16 for similar performance?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk4i0oz",
"fk53qwj"
],
"text": [
"how much HP a super car makes is rather a moot issue. more cylinders and more volume and larger turbos doesn't equate to more HP. there are both advantages and disadvantages to adding more turbos/turbo stages or using more cylinders in different configurations. so the answer is basically that's what type of engine the designer wanted to focus on. one wanted to use a W16 while the other wanted to use a V8. that fact by itself states nothing about what the performance should be except \\~1000hp is what the manufacturer decided on. in the jesko/chrion, a similarly speced engine, both now produce 1500hp instead of 1000hp.",
"First and foremost, Bugatti built a W16 explicitly for the purpose of \"because they can.\" That isn't to say it's not without it's benefits, but the Bugatti has always been a halo car, designed to showcase Volkswagen's finest capabilities. Now to talk about the numbers. Gasoline has an available energy density of about 45 megajoules per kilogram, about 10kWh per litre burned. A typical engine will extract 1/3 of that, so that 1 litre/hour corresponds to about 3kW output. That means that to extract 1000hp, (736kw) you have to have a fuel flow of just over 245litres/hour - which at 15:1 air:fuel ratio means 3676 kg of air per hour - which at 1.225 grams per litre equates to roughly 3 million litres of air - or roughly 833 litres/second. Rolls Royce did that with the Merlin engine by making it 27 litres - but to develop that power at a 1500rpm propeller speed (13 litres per revolution = “only” 260 litres at 1500rpm) they had to add superchargers to increase air pressure and run the engine at 3000rpm, gearing it down for the prop. A Merlin engine won’t fit in the back of a Bugatti. A heavily turbocharged 5 litre V8 can develop 1000hp but it would self destruct in the 12 minutes required to do a sustained speed run, what the manufacturer promises. No other car can promise to perform at it's peak level for nearly so long. Making an engine strong enough to last would result in a very heavy engine. 1000kW generators, expected to run continuously, are the size of cars so they can run slow enough that they don't suffer structural and material failures. Top fuel dragsters make 15,000 hp in a v8, but the engine has to undergo a complete tear down and rebuild after every single run. Just some numbers I dragged up from a similar comparison, the Veyron produces 1184 hp at 6400 rpm using 8 liters of engine - that is 23.125 horsepower per liter per kiloRPM. A Konigsegg produces 1124 hp at 7300 rpm with 5 liters of engine - that is 30.8 horsepower per liter per kiloRPM. By increasing the number of cylinders, they reduce the load per cylinder and increase reliability. Finally, I googled dyno charts for the two engines. You have to understand, it's not about peak numbers, you need to look at torque and horsepower over the entire RPM range, it's the area under the curve that matters. The W16 has a flat torque curve from 2,000 rpm onward, and horsepower absolutely skyrockets, and the Konigsegg just doesn't compare."
],
"score": [
9,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fgtaux
|
How does the faster R-CNN model work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk6u0gl"
],
"text": [
"A neural network works by flowing a bunch of inputs (anything, really, but for this stuff it's each pixel of an image) through nodes to outputs (decisions). The nodes perform some basic math combining inputs. They giggle the weights or coefficients for every node according to some math about how far off the output is until the output is better. Convolution is a mathmathical term for how two things get combined and affect each other. Pertaining to neural networks, it's a layer before you get to those raw math nodes to help bots match things. ie, \"this is how this image would affect that image\". \"With regions\", means you take the whole image-recognition CNN and test it on a specific rectangle of an image. \"FASTER\" just means they've got some shortcuts to help pick the region instead of trying random arbitrary rectangles in the image. So..... Look at an area of a picture. Does it share any features with the thing you're looking for? Is this what you're looking for?"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fgudyw
|
why CGI animation cost less to make than hand drawn animation but big CGI animated movies budget is always many times higher ?
|
In japanese anime nowadays there are alot of smart use of CGI to cut down on production cost. However most big CGI animated movies always cost 7-8 times higher than traditional hand drawn animated movies. Weathering with you and your name budget was about 9-11 million, while boss baby, frozen, kungfu panda was upward of 125-150 million.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk6y90g",
"fk7s9lp",
"fk7bdgc",
"fk6wbsx"
],
"text": [
"You can't say that CGI costs more or less than hand drawn animation because it doesn't. CGI has a wider range of potential costs than hand drawn animation, which is why its used in both expensive movies and cheap anime. With hand drawn animation the cost of fluid animation is mostly determined by how fast you want it done. If you want it done really fast you hire more animators, if you don't care, you hire less. But its difficult to drop the overall quality of the animation (and therefore, also drop the cost) without producing something that's jarring to watch. Likewise, its hard to increase the quality because there are practical limits as to how well humans can draw - particularly in a production environment. With CGI its much easier to alter the quality, and cost, of the CGI. And if you're looking for cheap CGI - as in the case of anime - the more CGI you order the cheaper it gets. The reason for this is that the main cost involved in cheap CGI is making the digital models, once you have those done its relatively inexpensive to shoot scenes with them. But CGI doesn't have to be cheap. If you want to make a CGI model that has a higher definition than the human eye is capable of perceiving, that's not a problem. All it takes to do that is to throw an obscene amount of money at the project. When you see Disney or Dreamworks movies that use a lot of CGI, chances are they spent more time (and money) developing the main character's model than most anime spend on an entire season's worth of CGI.",
"One answer that I don't see people mention: cheap TV shows use off-the-shelf software, whatever its limitations. Big CGI animated movies hire big teams of programmers and have them invent new software for each movie, to make new effects possible. For example, Monsters Inc wanted big furry monsters. There wasn't existing software to animate a monster with that much fur, so they invented it. Years later that same software trickles down to low-budget CGI TV shows. But low-budget shows never invent new effects, they just use what already exists.",
"A ps2 game costs less than a PS4 game. The CGI of a PS4 game is on a different level to a PS2 game. To make higher quality effects like water, light, fur, hair etc, takes a lot of skill and computing power. The stuff put out by Disney is very high quality. That is essentially the difference. Hand drawn stuff has \"high\" minimum cost because it's all manual and there's no way to mass produce, however, that doesn't mean it can't be extremely expensive too. What if you decided to animate at 60 frames per second? What if you started to animate every detail like background crowds, the shade and light of every tree? Very expensive. The real reason to use CGI is the scalability, editablity, reusability of the product as well as the process. E.g. if you create a tree for one movie, you can just put it into another movie. If you develop some cool snow effect tech, you can use it across all your CGI animations.",
"The budget didn't go exclusively to animation, I wouldn't be surprised if most of the production cost was actually the star voice actors for all the languages it's shown in. Also advertising is probably a much larger part of the overall budget"
],
"score": [
27,
5,
5,
3
],
"text_urls": [
[],
[],
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
fgvggy
|
how the storage of electronic data really works?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk72k1b"
],
"text": [
"There are different ways. Some things, like audio tape and floppy discs, magnetize tiny sections of the tape or disc. Magnetization may mean \"one\" and no magnetization \"zero\", or they may have varying strengths of magnetization and the strength is the worthwhile signal. Some store data in millions of tiny capacitors; each one can hold a ring electrical charge. If a computer looks for the charge and finds one, that's a one; if not, that's a zero. Some store data on optical discs; how a laser reflects back when you shine it at a certain spot on the discs encodes the data. Some flight recorders even make little holes in strips of aluminum foil. There are dozens of physical phenomena used. Basically any physical characteristic that can be set a certain way and reliably read can store data. If it can be reliably changed on command, that data can be changed."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fgxr3k
|
How does pausing and resuming downloads work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk7j7iw"
],
"text": [
"The file being downloaded is a simple (GET) request. You open the connection, and read the incoming data (bytes) until the connection closes. You also know the size of the response from the beginning, that's how you have a percentage. For resuming the download request, you just do a \"range\" request: GET /download.zip HTTP/1.1 Host: URL_0 Range: bytes=0-1023 which skips the portion of the response you have already received. Though only the size of the file, and the validity of the incoming bytes is verified. If the server doesn't resume correctly or the response is not the exact same, you get a corrupted file. That's why hashing is being used for serious downloads (Firmware Updates etc.)."
],
"score": [
19
],
"text_urls": [
[
"example.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
fgzoy4
|
How do electronics eventually break? Do the connections on the motherboard get weaker or thinner over time?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk7ury1",
"fk7upea",
"fk7v8gp"
],
"text": [
"There can be different causes of failure. The circuit board will usually have exposed copper and tin which will over time corrode and wither away disconnecting the components from each other. Tin is also quite brittle so if the device is dropped the tin might develop cracks which after repeated drops can go clean through the connection. A similar thing can happen to the circuit board itself. If you drop it the force from the mountings to the components will go through the circuit board which can cause it to crack. These cracks can sever vital traces and prevent the electronics from working. But the chips themselves can also stop working for various reasons. They are made of different materials which can expand at different rates when the temperature changes. This may cause tiny cracks that eventually cuts a wire inside the chip. Transistors may also wear out with use. This is especially noticeable with the transistors used in flash memory as they can be permanently damaged after just a few thousand write operations.",
"Electronics can suffer physic damage such as being dropped or banged which can damage the parts. One of the most common problems is damaging the power outlet connector because the adapter sticks out from the machine so it's more prone to breaking the connector. Many electronic devices have physical moving parts like fans and motors that wear out with time. There's also environmental factors. Electronics do not like heat and the accumulation of dust will cause parts to overheat in time, which can cause solder joints and individual electronic components to wear out. Oxidation is another problem. Rust can accumulate on the parts causing corrosion damage and an oxidation layer can block electrical contacts.",
"Sometimes solder connections aren’t very strong, and they corrode slightly, which breaks a connection. Sometimes (if it’s an item that sees temperature or humidity fluctuations) the environmental fluctuations will cause problems. There may be corrosion in power connections, there might be physical failure of an electrical connection from expansion and contraction... Sometimes individual components will fail. Electrolytic capacitors can fail, because they’re complex for their size (layers of foil, insulators, and liquid parts). As electronics get smaller, their power demands decrease. The electrical paths (wiring, circuit board traces, and the internal traces in integrated circuits) are smaller by _a lot_ than in 1980s electronics. Older electronics were more robust, but required more power. The delicate nature of more modern electronics can cause them to fail in ways that aren’t apparent, since variation in electronic components may happen inside an integrated circuit, or somewhere invisible to the user. Time, environment, and random chance make a difference. I have a GPS unit in my car that is actively dying, and the circuits that provide the information are fine. The display, however, is losing contact with the circuit board. The connections for those are often a conductive rubber strip, adhered to the contacts of the display. I can squeeze the sides of the GPS and the map displayed clears up, but it’s clear that the age of the GPS is there. It’s fallen off my windshield a lot, which seems to have loosened a lot of connections."
],
"score": [
11,
9,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fgztkc
|
How did ancient civilizations prospect for iron ore
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk7v6gd",
"fk7wbsj",
"fk7v28o",
"fk7wx39",
"fk8hunq"
],
"text": [
"It is almost impossible for metalworking civilizations to start with iron. Copper is a far easier metal to start with because it can be accidentally smelted. Put a copper bearing rock in a hot campfire, and it will bleed copper. In addition to being pretty easy to smelt, copper is just hard enough that it is able to make fairly decent tools on its own. So before the Bronze Age started, there was almost certainly a very small copper age. The copper age taught people that some rocks give metals when heated, which caused them to start experimenting with hotter fires and trying a bunch of different types of rock. This eventually lead to the production of more metals like tin and eventually iron. Most likely the reason Native Americans never develop metalworking beyond gold working was because they're just doesn't happen to be enough copper deposits near the surface to have got them started.",
"Iron Ore is visible on the surface as red streaks due to the rust. Once ancient peoples recognized that these rocks could be smelted or slagged into iron then they kept eyes open for them. Mining for iron in Europe goes back as far as Roman times. The Romans actively mined for minerals, but mines were relatively shallow due to the difficulties of extracting water from the tunnels. Much of medieval era iron though was *bog iron* which required wading through swamps to find the iron rich rocks.",
"Iron ore is very easy to find on the surface. This is because of its distinct red colour. Just look for a red rock and you have found your iron ore mine. Alternatively look for red water as this water most likely have flowed through an iron ore vein.",
"People don’t use metal detectors today to prospect for iron ore. Iron is actually quite easy to find - it’s almost always in an oxyde or sulphite form, and the soil around deposits will reflect that by coloration. How did they know that red soil leads to iron? Because previously they used bronze, and before that copper and noticed that certain minerals indicate metal presence - copper appears in elemental but also other forms, and needed heating to figure out; once you discovered that certain rocks yield metal, you’d experiment with that other rocks that looks red, and the one that looks black etc etc etc.",
"The first part of [this video]( URL_0 ) by Primitive Skills shows how to find promising rocks to extract iron from."
],
"score": [
39,
16,
8,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[
"https://www.youtube.com/watch?v=0H-NCgWZZfw&list=PLu5jI_OEKlo-deJv0tlKmZ7ISGg_YHdCY&index=69"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
fh1m4c
|
What does deep learning do exactly? How does it do it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk89rky",
"fk8itj9"
],
"text": [
"In conventional programming, you write very exact instructions. A computer programme won't do anything you didn't instruct first. Most bugs are really just mistakes in our instructions. With deep learning methods we write software that teaches itself certain skills through examples. For example, a deep learning image recognition algorithm can be shown thousands or millions of examples of kittens so that it can learn to recognise kittens in images it's never seen before. [Here's a fantastic video]( URL_0 ) on someone who wrote some code that creates a simple virtual creature with legs and then runs dozens upon dozens simulations where it tries to move it's legs in different fashions in an attempt to learn how to walk. Just watch the vid, it explains everything.",
"Deep Learning is a bit of jargon that describes a neural network with a large number of consecutive layers. So what is a 'neural network'? Let's say you want to buy a house. You want a certain number of bedrooms, a certain number of bathrooms, a certain type of neighborhood, a certain kind of garage, a number of floors, price range, etc. All of these are called 'features' by the kind of people who use phrases like 'neural network'. So you take all these features, weight them somehow and end up with a number that expresses how much you want any particular house. Maybe you think price range is more important than bathroom count or number of floors is less important neighborhood - you assign weights to these and then just compute which option is best. But what happens when you don't know what weights to use? This happens with classification problems all the time. I can show you two pictures - one with a stop sign and one without - that you can easily discriminate. You can sort all such pictures into two piles pretty easily. But what you can't do easily is write an equation that takes the colors of every individual pixel and computes the difference between 'stop sign picture' and 'not a stop sign picture'. It's simply too complex. Instead what we do is 'train' an equation. We write an incredibly complex set of simultaneous equations where every feature has a weight. All we need to do is figure out what those weights should be and we'll have a mathematical structure that can predict whether a picture has a stop sign or not based solely on the colors of each individual pixel. That's basically all a neural net is. Deep Learning is simply a way of building a neural net that's more manageable (and more computable) than simply creating a single massive set of simultaneous equations. Instead of trying to do the whole problem at once, we divide it up and incrementally solve the problem in an abstract fashion layer-by-layer. The more layers, the better we can discriminate our two sets - but the more difficult figuring out the weights becomes."
],
"score": [
8,
5
],
"text_urls": [
[
"https://www.youtube.com/watch?v=K-wIZuAA3EY"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fh1uyr
|
Why do special effects in movies cost so much money to produce?
|
I see posts all the time talking about the million dollar special effects and such, but isn't it just a team of people using software? Why and how do (decent) special effects have such a high price?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk8aedv",
"fk89g2q",
"fk8atc6",
"fk8aa52",
"fk8f8az",
"fk8bir3"
],
"text": [
"> isn't it just a team of people using software? yes. they're paying those people. also lots of times the software they're using was also developed in house, so you'd be paying not just the graphics people but the programmers who developed the software. if the parent company is using a specific production company to do their effects, or entire movies like pixar, they're paying the company as well and not just the direct labor of the employees. at that point its more of a supply/demand situation for costs since the company also needs to make a profit. the sonic redesign cost $5 million alone, and employee labor would have been the majority of that cost (probably). it delayed the movie by 3 months. assuming the team all made a salary of 50k yearly (avg, est, etc) 5 mil will pay a team of 33ish people to work for 3 months. i'm not invested enough to see how many people worked on that team, but CGI teams are pretty big for high CGI movies currently (based on watching crazy long credits rolling)",
"Time = money, skilled workers = money in every industry. Visual effect takes a grate deal of time for highly skilled workers.",
"You mean a team of highly skilled and highly paid visual effects engineers with project managers, middle management, and other staff? Why would it cost millions of dollars to pay for those people? A team of 10 people getting paid $100k salary is a million dollars. Watch the movie credits for VFX engineers. Heres the list for Avengers Endgame URL_0",
"They have to pay the artists creating those effects, and there are usually dozens or more working on a scene at any given time. Those talented people are in such high demand that, yeah, that price per hour gets cranked up. And trust that those effects take a very long time to produce. It's very difficult, taxxing, and time consuming work.",
"Developing software is not cheap. For a well developed application you can easy spend millions in development. The software there using is complex: it has to create very realistic images, in high detail. It is also very specific for the movie. It will allways take a lot of work from both developers and artists to adapt the software they have to the movie.",
"It's not *just* a team of people using software. It's a *large* team of highly-trained professionals, usually with some sort of higher education qualification or degree, along with experience in illustration, animation, special or practical effects, and art in general who, as a kicker, are generally part of a union... using software that costs several thousands of dollars per license, that needs to run on very high-performance computers to meet deadlines. It's not like Special Effects/CGI artists are becoming instant millionaires, but they can live comfortably in the LA/SF Bay area where the cost of living is pretty ridiculously high. Also unlike most other areas of technology: Faster tech makes special effects work move slower; in the early days of 3d rendering, a character model would have a few hundred to a thousand or so polygons to render, and on 1990s-2000s hardware, that took months to render at a rate that was still too slow for most peoples' tastes. Now, though, instead of rendering low-polygon graphics quickly, they take roughly the same rendering time to render high-definition graphics, textures, models, etc; but that higher definition means more fine details that take more artists more man-hours to get meticulously right where some shortcuts may have worked in the past since the display quality wouldn't even show the slightly sloppy methods, now you have to be extra-careful compared to what you did on your last project."
],
"score": [
14,
10,
4,
3,
3,
3
],
"text_urls": [
[],
[],
[
"https://www.polygon.com/2019/5/8/18531405/avengers-endgame-end-credits-visual-effects-artists"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fh40ra
|
Why can a banana peel be used to navigate my phone?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk8pjlz"
],
"text": [
"Just like your finger, a banana has capacitance. That capacitance is in the proper range to allow the screen to function, just like it would with your finger."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fh5jjw
|
Normal "system" memory versus graphics memory
|
What is the difference between the DDR 3, 4 or 5 you install as system memory and the GDDR 4, 5, 5X or 6 used in graphics cards? What makes each of them better for their respective applications?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fk8zxul"
],
"text": [
"Graphics memory is designed for ludicrous throughput and custom applications. Graphics cards need access to massive memory bandwidth to do their job, a single 4K frame is ~25 MB and the GPU will be expected to generate at least 60 of them per second requiring a minimum of 12 Gbps of memory bandwidth to achieve 60 FPS at 4k. If you want to run 8x FSAA(full scene anti-aliasing) then you need to generate each frame at 8x the resolution or 32K equivalent and then down sample it. This gives you 1.6 GB **per frame** and 768 Gbps of required memory bandwidth. The Graphics RAM on a GPU serves as its input buffer storing textures that it needs to reference during rendering and storing the finally rendered scene. Because of this insane bandwidth requirement, GPUs often talk to several chips in parallel so they can have up to 512 bit wide memory buses so each clock edge can give them 512 bits of data and then they run at quite high frequencies. An nVidia 2080 TI has a memory bandwidth of 4,928 Gbps. Standard memory is designed to be compatible with every system, as such it has an agreed upon bus width (64 bits) and frequency set. While it will sometimes have lower latency than graphics ram and is generally significantly cheaper per GB, even the fastest stick of DDR4 can only give you 200 Gbps, but this is more than enough because your CPU isn't handling huge quantities of data generally. Its restricted on doing math on what it can fit in its L1 and L2 cache, everything else is a longggg wait for a CPU."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fhbs50
|
Why do USBs and memory cards get corrupted so easily?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fka7hv8"
],
"text": [
"If you’ve been just pulling them out without safely ejecting them then there is a higher chance of failure of the files but I rarely get a USB completely fail beyond repair so I don’t know what you’re doing with them"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fhc042
|
Why are absurdly misspelled scams circulated?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fka6qnf"
],
"text": [
"From what I understand, they're written like that on purpose. It helps them immediately weed out the people who would be smart enough to figure out it's a scam partway through the process. The people who see all the spelling errors and don't immediately have red flags go up are generally gullible enough to go through the whole thing without catching on."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fhwmct
|
How did Morse code machines connect and send electromagnetic pulses over long distances?
|
They aren't connected via a very long wire, are they? P.S I'd like to understand the physics behind it, not how Morse code works.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkdq2uo",
"fkdra83",
"fkdq39j"
],
"text": [
"It was literally done with wires. Back in the day, sending a telegram was called 'sending a wire' and when radio came in it was known as 'wireless telegraphy.' If you look at pictures of old time steam trains there's almost always a telegraph wire running next to the train tracks.",
"They did have long wires, yes. You had long telegraph wires that would eventually span the entire globe. The longest ones were crossing the atlantic. Before the telegraph system there were the semaphore system which used a system with two flags waved in different positions. There were big semaphore towers that could be seen for miles using big mechanical arms to spell out the letters. This system allowed people to send messages fast across the country and even to some degree around the world. But with the electricity and the telegraph system that used the morse codes or other types of codes message speed would increase from minutes to seconds. It should be noted that most people did not have a telegraph station at home. There were usually just one telegraph station in each city and messages might have needed to be relayed through several of these telegraph stations as most did not have a direct connection to each other. So you would normally write a short telegraph, send it with a runner to the nearest telegraph station, they would pass it along the wire until it reached the city you were sending the telegram to, and then it would get written down and sent by a runner to the destination. Telegrams did also use wireless technology where it was required. First they used similar systems of visible communication that the semaphore system did but with shutters that opened and closed in front of a spotlight or just a piece of canvas. This was mostly used on ships but it did also transition to airplanes and tanks. Some of the last such systems were deployed in tanks during WWII. When radio was invented it was natural for ships to switch to radiotelegraph. However as frequencies had not been discovered they were all sending on top of each other. Part of the problem for Titanic was that their passengers sent so many telegrams that it prevented the captains in the entire North Atlantic from sending weather reports and ice reports to each other and the ship closest to the Titanic and actually able to rescue them even turned off their radio and went to sleep because of the noise of all the telegrams going from the Titanic to land meaning they never received the CQD/SOS distress messages. As telephones were invented and became more common a lot of the old telegraph wires were converted to phone wires. And as digital communication was invented those were eventually replaced with fiber optic lines. However most of them still takes the same routes as the old telegraph wires. That includes the transatlantic wires which still to this day uses the same beaches.",
"Depending on era and location, it was both radio and wired, such as the *Transatlantic* Telegraph Cable"
],
"score": [
10,
8,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fi7jmv
|
Why is it required to turn the sound bar up to 60+ on some streaming services/shows whereas others work fine at 15-20?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkftl2m"
],
"text": [
"At least part of this likely comes down to how the sound is mastered and mixed; some shows/services just generally master their baseline volume to be louder than others. Sometimes this is due to thematic vs practical concerns; an action movie is likely to have a sound mix with louder vocal levels than some other shows, because the voices need to be heard over or in contrast to gunfire and explosions without the explosions being too loud, so if an explosion is too loud at volume 30, then the voice of the audio will be mixed to be clearly audible at that same volume level. Contrast to a highly suspenseful horror or drama where the juxtaposition of people whispering to jump scares or emotional scenes with people loudly yelling or crying, and the volume becomes more dynamic, but at the cost of needing to turn up the volume to hear the whisper-y bits."
],
"score": [
41
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fi7z3m
|
What is the process for making tea and coffee decaffeinated?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkfq6vi"
],
"text": [
"They use a solvent that extracts Caffeine but not the rest of the chemical components that make up Coffee. A solvent is a liquid chemical that can be used to dissolve a solid chemical, for example water is a good solvent for Sodium Chloride (Table salt), where one liter (L) of water dissolves roughly 360 grams (0.36kg) of it. A dissolved solid has been completely surrounded by molecules of the solvent, making it act as if its a part of solvent liquid (like salt in water, which can only be separated with filtering or boiling). Then, we need to understand the difference between *non-polar* and *polar* solvents. An example of a ***polar solvent*** is water, because it has a negative electric charge on the Oxygen and a positive electric charge on the Hydrogens. Therefore it can be said that it has two *oppositely charged poles*, IE it is ***polar***. On the contrary, a ***non-polar*** solvent would be Benzene, a constituent of gasoline. This molecule has basically the same atoms all around, which means that it has no negative or positive charges. Therefore it can be said that it has no *oppositely charged poles*, IE it is ***non-polar***. Most solvents fall somewhere in between, but are also usually called *non-polar*. These include Acetone (Nail polish remover), Isopropane and Alcohol. However, true *non-polar* solvents are insoluble in water (try mixing vegetable oil and water - they don't mix at all). First we have to establish that Tea and Coffee is normally extracted from leaves/beans in boiling water. So any compound that is not soluble in boiling water can be removed without a significant change of taste, texture and composition in the finished Tea or Coffee. Now, Caffeine has a very interesting property that can be exploited for its extraction. It is both very soluble in warm water at 660mg per mL, or 0.66kg/L. It is however not very soluble in room-temperature water, at 20mg/mL or 0.02kg/L. While also being highly soluble in boiling water, it is very fat-soluble and is highly soluble in non-polar solvents. Most Coffee compounds however need roasting to be soluble in either fat or water. So what Coffee Decaffeination does is exploit this property by one of the following methods; 1. Direct Extraction: Green Coffee beans are steamed to remove the Caffeine from their interior, and they are then rinsed with a non-polar solvent. When the non-polar solvent is washed off, only Caffeine has been removed from the beans. 2. Indirect Extraction: Green Coffee beans are soaked in water for several hours, making kinda a very strong pot of coffee. Then they use DMSO (a non-polar solvent that does not mix with water) which separates the Caffeine into the DMSO and the rest of the coffee compounds into the water. The same water is recycled over and over, so after doing the processes for a while the water does not take up more non-caffeine coffee compounds as they are already present to the \"limit\" in the water. 3. Supercritical CO2: After steaming green Coffee beans, they circulate high-pressure Carbon Dioxide into a chamber with the Coffee which acts as a semi-polar solvent. It removes the Caffeine and leaves the rest in the beans. 4. Triglyceride Process: Same as process 2, but instead of directly using DMSO the coffee beans are \"boiled\" in water rich with Glycerine and water-soluble fats. These draw out the Caffeine into the water, which can then be treated with DMSO. This retains more flavour because the oil-infused coffee water can be dried and re-used, giving slightly higher efficiency. Tea is usually decaffeinated with process 1 or 3."
],
"score": [
14
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fiay06
|
Why we can see the source code for an HTML page but not for a program, unless the programmer (or the owner) shares it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkg7yek",
"fkg5nq0",
"fkg6po1",
"fkg5tm8",
"fkgiz1e"
],
"text": [
"So the other answers aren't wrong, but I feel they leave a bit out. In computing, there are a few different ways to program. These are typically referred to as being low-level (closer to the native 1's and 0's that computers understand) and high-level (closer to a human-readable language) At the lowest level we have assembly. This is some of the most bare-bones code, where instructions are written out line by line for what each part of the computer does at each step of the code; what values in memory get moved into what part of the processor and what operation is done and where the output goes, *really* low-level stuff. A level above that and we have the *compiled languages*; these are languages like the C/C++/C# family, along with a few others that are largely lost to time. When you code in C or C++, you get some advantages like being able to automate a lot of the things you would have to do manually in Assembly, like cleaning up memory after you were done using it, and the code, while it still isn't any natural language, is more understandable to the average person; it's kind of like if you are fluent in Spanish and you try to read Portugese: some words are different and you might not understand some context in some places, but you can discern the general gist if you understand some basic concepts. These are called compiled languages because the text file that is your source code has to be run through a program called a compiler, which uses a set of rules to convert that code you wrote into raw machine code, and packages it so it can be run as a .exe Then a level up, we have interpreted languages - these are languages like Python and Ruby, and they do for C/C++/C# what those languages did for Assembly: make it easier to read and write more complex programs in less human hours. These are run through a program called an interpreter, and unlike with a compiler, the interpreter has to be called each time the program file is run. So unlike in C variants, where the compiler spits out a .exe, a python file requires being sent into a python interpreter to give any outputs (at least generally; there are ways to get a .exe out of it, but it generally takes longer to do, as fundamentally the programs end up being bigger). Finally you have scripting languages; these are sometimes considered not \"real\" languages, but the idea is that you have a program (like a web browser) that looks at code fed to it and then follows it like a script using its interface. These tend to be more specialized than any other type of programs, and it's used as a way to share content without allowing random untrusted code to run directly with your user permissions (not that that always works, but...) - so for instance a web browser's scripting languages (html, javascript, css, etc;) lets you call predetermined elements from top to bottom of a page which the web browser then displays as best as it can, calling the images and whatnot to use during runtime. Because scripting languages and interpreted languages are taking the source code and reading it during the runtime of the program, as opposed to putting out an independent program to be run on its own, it needs to be able to \"see\" that code, and if you have access to the program that means you can access it. Compared to compiled programs which aren't easy to reverse from bytes to readable C (things like variable names get erased during reverse-engineering and makes it hard to track what the program is doing, as the computer discards that during compiling; it's there for human readability). Because interpreted languages and scripting languages fundamentally",
"The code in an executable isn't written in characters but in plain bits/bytes the CPU can use \"natively\" (consider reading what a compiler does) In addition to this, you wouldn't want everyone to be able to steal your code",
"HTML page isn't the executed code. it's the data that's being read and rendered by the browser. on other hand, Javascript IS code. but it's sent in clear text that's then interpreted by the browser and then converted into executable binary code on the fly and then executed",
"A program is run through a compiler when the code is finished, which converts the code into instructions for the processor, 1s and 0s basically, and the result thrown into an \".exe\" file. Html is interpreted, which means that other software runs through code statements as they are so they don't get lost in the compilation process.",
"There are lots of programs you can see the code for, php, python, Visual Basic, JavaScript, etc."
],
"score": [
11,
5,
4,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fijmd9
|
If you play a game on emulator and you accelerate your emulation speed, time required to save the game decreases.How does that happen?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkhgkdl",
"fkie9jk",
"fkhmy6m",
"fkio15k"
],
"text": [
"In many older cases, the screen or progress bar that you see was coded as a specific amount of time rather than a progression of the process. So when you speed up the clock on a game, that speeds up. Often, the time it took to actually save was well below the time it took the animation, they were just being cautious. Especially on consoles.",
"Modern computers are many, many times faster than the processors used on those old video game machines. Emulators force them to slow down to imitate the old system, and that's everything it does, including saving. Accelerating just means it doesn't slow it down as much and that also includes saving.",
"There are wait times built into the programs written out in milliseconds. Increasing the clock speed changes how fast the program's clock runs, so it waits less time at each operation. I'm thinking specifically of it reading, pausing, writing, pausing, then reading to verify the data was written successfully.",
"Simply put, the instructions on *how* - and what - to save(where to put which piece of info to be kept) are part of the game itself, so the saving is influenced by the speed of the virtual processor in the emulator because the saving is done *inside* the emulation. Contrast this with the emulators own save function, often labelled something like \"quicksave\", where the emulator itself just copies the whole memory the game uses in that specific state, so it can be resumed later. This doesn't get slowed, since it's done *outside* the emulation. edit: A bit of context: Because emulators basically create all the hardware of the original machine virtually(or at least, provide pieces of code that give the same result as those circuit boards), emulation is always strictly governed by a central clock speed for the emulated console, and that is what you multiply when you pick \"200%\", so then everything that was originally done on the console gets twice as fast."
],
"score": [
28,
6,
3,
3
],
"text_urls": [
[],
[],
[],
[]
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|
[
"url"
] |
[
"url"
] |
|
fijvje
|
what is end to end encryption and what does it mean to end it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkhjif4",
"fki4fkp",
"fkhkoi1",
"fkjjf5m"
],
"text": [
"A lot of encryption in communication is in steps. Your connection between your computer and the server (eg: Skype) is encrypted, but then Skype gets a copy of your message without encryption. That means they can read it, save it, give it to someone else, or feed it into their profiling software that serves you ads. So if you tell your friend that you're thinking of buying a new PC, don't be surprised when ads for Dell suddenly become common. Skype will re-encrypt the message as it goes to its actual intended recipient. (I don't know that Skype actually does this, I'm just pulling names out of my ass for the sake of example) So if either of you are on open WiFi, people around you can't read your messages, but Skype themselves can. End-to-end encryption means that the message stays encrypted all the way until the point your friend receives it and they can read it. This means skype (or whoever is the middle man) can't actually see what you wrote.",
"It means it is scrambled when it leaves the sender, and only unscramble when it arrives at the receiver. No one in between can read it.",
"End-to-end encryption is pretty much what it says on the tin: its when data is encrypted before it leaves the sender, and only decrypted at the receiver. Its important to note that exactly what \"end-to-end\" means depends on the intended sender and receiver. On a practical level, consider something like Facebook messenger. It could be considered to have a form of end-to-end encryption, in that I (as a user of Facebook) encrypt the message I typed in my browser, and send it to Facebook to be decrypted. However, this generally isn't what people talk about when they say end-to-end. If I am sending a message to you via Messenger, \"end-to-end\" encryption would usually mean that I encrypt it and you decrypt it, and Facebook has no way of reading the message despite the fact that it is actually handling the message passing transaction. By contrast, WhatsApp apparently \\*does\\* do this: any message I send to you via WhatsApp \\*cannot\\* be read by the company, only by you and me.",
"Imagine you send a postcard to your friend with confidential information on it. You can read it, your friend can read it, your mail carrier can read it, the people at the processing facility can read it, anyone walking by your mailbox while it's sitting there can read it, and if someone mugs your mail carrier, they can read it too. This is completely unencrypted communication. Now imagine instead that you set up a secret code with the post office so that when you send letters, you write them in code, then the post office de-codes the letter when they get it, passes it around internally until it gets to your friends city, where they then encode it for your friend using a code that your friend set up with them, and then your friend decodes it in the end. This is \"encryption in transit\" and is what happens when you connect to a site over HTTPS or similar technology. You can read the message, the people at the processing facility can read the message and your friend can read the message, but your carrier, and someone mugging your carrier can't. Now imagine just like the above, but instead of decoding your message when it arrives at the post office, they instead leave it coded until they're ready to deliver it to your friend, at which point it's briefly decoded, then re-encoded for your friend and sent on. This is like \"encryption at rest\", and it's effectively just about limiting the number of people in the middle who can read your message. Now instead of everyone at the post office being able to read your message while it's there, only the specific individuals decoding it and re-encoding it can. It still doesn't prevent the post office from being able to decrypt your message (because you set up the code with them) but it's a layer of additional security so that if say for example your post office was robbed, even if they got all the letters, because they're not decoded until they need to be sent out, the robbers can't read the message. Lastly, \"end to end encryption\" says instead of setting up a code with the post office, you set up a code with your friend directly. You and your friend agree on your super secret code, and you encode your message and mail it out. Your carrier can't read it, their mugger can't read it, the workers at the post office can't read it, a robber who breaks into the post office can't read it and neither can your friend's carrier. Only you and your friend can read it. So why not use end to end encryption all the time? Because it's a hard problem to solve. Imagine needing to contact every single person you ever wanted to send a message to before you send them a message and first working out a secret code to use while you communicate. This is usually accomplished by way of something called public key or asymetric cryptography, which lets someone publish one part of an encryption key pair publicly that others can encrypt data with, but can't be used to decrypt the data, and then they can decrypt it on their end with the other private half of the encryption key. But distributing public keys can be difficult because they're big so it's not as simple as telling someone your phone number. Politicians are trying to end end to end encryption by either forcing you to use one of the earlier less secure methods, or by requiring services to either require you to share your private keys with them to communicate, or build weak keys that have back doors (like a \"master key\" for a hotel, each room has their own key, but the owner can use one key to get into them all). They're trying to end it for the usual reasons, crime, drugs, dissidents and the children. The problem is no master key is safe, if it can be leaked, it eventually will get leaked, and when that happens nothing that was encrypted with the weak keys is secure anymore."
],
"score": [
4,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
fipzkh
|
The difference between SMS, telephone, data and Wi-Fi
|
I have to explain to old people the difference between SMS, telephone, data and Wi-Fi. Please help.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkik3va",
"fkikdc0"
],
"text": [
"Wi-fi and data are both just \"connections\" to the internet. Wi-fi is the protocol (\"language\") that connects your phone to your wired internet in your house, while data is the long-range protocol that connects your phone to the wired internet at the phone tower. SMS and telephone both also talk to the phone tower, but don't connect to the internet. Instead they connect to special systems that transfer text (SMS) or audio (telephone) information to another user's device.",
"SMS is a special kind of data that's send between cell phones and their towers. It's how the cell tower knows that the phone is near, plus messages to the phone can be added. Telephone is a digitized sound system where two streams of sound are digitized and sent between two phones that are connect in what's called a \"phone call\". Data (in this communications context) is Internet (IP packets) sent to and from the smartphone using its data radio. This is related to but separate from the digital system that is used to send the digitized sound during a phone call. WiFi is Internet sent to and from the phone using a different set of radio frequencies than the ones that the cellular carrier use. This is typically only within a building/house/apartment, and the cell carrier doesn't provide this. It can work on a smartphone that doesn't have a phone number assigned."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fiucv8
|
What is RAM and what does it do?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkj9mdh",
"fkj9ysc"
],
"text": [
"It's basically the short term memory for the system When you load a game, everything you see is being held in the ram. When there is a loading screen, it is transferring the data from the storage drive to the ram",
"Imagine your computer is a desk. The hard drive is the filing cabinet and drawers. Every time you need a file it takes time to open the drawer, find the right one, and open it up and read it. Now, your RAM is your actual desktop. The physical size of the desktop limits the amount of files you could have open at once. A bigger desktop lets you work with more files simultaneously without having to open the filing cabinet, search for the right file, pull it out, etc."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fiuw17
|
how did the TV, computer, and telephone have such a vast reduction in size and are able to do you so much more at a much higher quality?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkjcq3o",
"fkjd77u",
"fkjnnjt",
"fkjpqmz",
"fkjd6p7"
],
"text": [
"The main technology that makes all of that happen is the transistor - a little gate that can let electricity through or prevent it from flowing through. Currently, they are as small as single-digit nanometers in length. Thats significantly smaller than a human hair. The technology needed to be able to manufacture that level of precision is not something we've had access to for long. Our ability to manufacture those transistors at smaller and smaller sizes is ultimately what has been the limiting factor. Over time, we've seen these shrink at a pretty predictable rate - and the advancements made in every sector that relies on them have improved along with them.",
"TVs and computers used to use a different method of displaying the image on the screen. ([Cathode Ray Tube]( URL_0 )) They used to work like a projector, inside the back end of the tv box a device would shoot the image onto the TV/PC screen. Now we have liquid Crystal and light emitting diode displays which are essentially a sheet of individual pixels that change colors to represent the image being displayed. Bundle that with shrinking the size of the hardware inside (basically by squeezing everything closer together than we could decades ago) and you've got smaller devices.",
"In addition to everyone else's answers, the invention of LEDs served to reduce the size of basically anything with a screen. They are both smaller and more energy efficient, meaning less space to hold them, less space to account for power management, and heat dissipation.",
"Believe it or not, improvements in optics. Microchips are made by projecting an image onto some chemicals. Every time the lenses that do this get better, we can fit more 'parts' onto an individual chip. We're up into the billions!",
"The exact answer is different for each of those things, but it seems like the basic question is how did we manage to get more processing power on smaller devices. The simple answer is we managed to find ways to fit more transistors (things which tell electricity what to do) onto computer chips. Some of that was by finding new materials to use for the transistors, some of it was by using things like lasers and UV light to add things far to small for any hand or machine to add manually. There’s a famous law in computing called Moore’s Law, which (paraphrased) states that the number of transistors you can fit per inch doubles every 18 months. That was changed to processing power doubles every 18 months along the way because the number of transistors isn’t the only thing being changed, nor is it necessarily the most important, and at this point it’s more of an aspirational goal that chip makers look towards than a law or prediction. In short, we used new materials like germanium and silicon, along with new techniques like using light to “burn” things onto the chips instead of physically putting them there, which let us fit more and more stuff into the same space."
],
"score": [
92,
14,
8,
7,
3
],
"text_urls": [
[],
[
"https://techterms.com/definition/crt"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fivz08
|
How does end-to-end encryption key exchange work?
|
If data is encrypted at one device and decrypted at the other, how are the keys shared without them being intercepted as well?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkjrth2",
"fkjkiic"
],
"text": [
"Alice puts a padlock on a box. Puts the key in her pocket. Ships locked box to Bob. Bob receives locked box. Doesn't have key; key is in Alice's pocket. Bob puts second padlock on box. Puts key in his pocket. Ships double-locked box back to Alice. Alice receives double-locked box. Uses her key to remove first lock. Ships it back to Bob. Bob removes lock. Bob opens box. ----- At no point did the keys travel through the postal service. At no point was the box unlocked in transit.",
"There are 2 keys: public key and private key. The public key can be used to encrypt something, and the matching private key can decrypt it. I can give you my public key, and you can encrypt whatever you want with it and give that encrypted object back to me. The only thing that can decrypt that object is my private key, which only I have and have given it to nobody. It doesn't matter if my public key is intercepted when I give it to you because it is used to encrypt, not decrypt."
],
"score": [
20,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fj03cn
|
What is NAT? And why there are online games that are not using NAT Filter?
|
So I played Destiny 2 and Warzone; they both use NAT Type (Strict, Moderate, Open) to filter the players. But most games that I play like Apex Legends, PUBG, Paladins, etc do not have that NAT Type filtering, at least they do not show our NAT type in-game compare to the other two that I mentioned. So I have 3 questions to be answered. 1. What is NAT Type in the online game? 2. What's the difference between games that have NAT type and games that do not have NAT type? 3. Why they use NAT type filtering, to begin with? Thank you. Sorry for my bad English.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkk6wpn"
],
"text": [
"So NAT stands for Network Address Translation, its a technique for dealing with the fact that ISPs don't have enough internet addresses to give one to every device on the internet. Instead they'll give a network address to your home router, then your home router will give a private (non-internet) address to all devices on your network. The problem with this is from the internet's perspective all your devices have the same name. When a message comes from the internet, the NAT (in your home router), needs to be able to figure out which device the message is for. For \"normal\" messages like when you request a web-page, this is fairly easy as it can just remember who most recently requested a web-page from that server, and forward the packet onto that device. However when you start doing \"Peer to Peer\" messaging this becomes harder. With P2P, you don't send messages to a server, but you send it to another user's device. Depending on how exactly the other device's home network router is setup this could be more difficult. The three \"NAT Types\" in Destiny are basically the three different ways a home network could be configured. 1. Open - This means there is either no NAT on your home network, Or it might mean that your home network router has a more advanced NAT wich can be asked by the device to automatically forward the required messages properly (\"port forwarding\" or \"UPnP\". 2. Strict - Your home network has a basic NAT which blocks all incoming messages that aren't replies to requests that it has seen. 3. Moderate - This is a bit more complicated. There's a way to work around NAT by instead of just sending a message to the other user's address, directly (which will be blocked, as the NAT doesn't know which private address to forward) you arrange with the help of a real server for both of you to try to connect to each other simultaneously. This way both NATs think that an outgoing request message has been sent, so knows how to forward the \"reply\" back to the correct device. This is known as \"hole punching\" or \"nat traversal\". This works on certain routers but not all. Know these behaviours explains why only certain types can connect to certain types. Any NAT type can connect to a \"Open\" device, because as far as the internet net is concerned the NAT doesn't get in the way and they can treat it like a real server. \"Moderate\" devices can use the hole punching technique to connect to other \"Moderate\" devices, and can also do the same with \"Open\" devices (although the hole punching only needs to be done for one side in this case). \"Strict\" devices can only connect outward, and aren't able to do the \"hole punching\", so they can only connect to \"Open devices\" and can't receive incoming connections. Finally, you ask why doesn't this apply to all games? The reason is that some games do P2P matchmaking, where one of the player's XBox/Playstation actually becomes the server and hosts the game. Other games have centralised servers that everyone connects to. The latter situations works better as \"real\" servers are all \"Open\" (they have no NAT) and anyone can connect to them. But this means the game company must pay to host the server. Whereas P2P is more flaky, but cheaper to run."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fjbgaa
|
How does a fighter plane know it’s been locked on by an enemy fighter?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fklytw7",
"fklywht"
],
"text": [
"Military craft have a device called a radar warning receiver. It has antennae that look for RF energy, and if it detects a pattern of a known hostile radar system or missile, it alerts the pilot and engages countermeasures if applicable.",
"Radar beams out a radio signal and listens for its return from objects to be tracked. A radar in search mode will be scanning back and forth across the entire sky at a relatively low frequency. When that radar locks on to an aircraft it will start rapidly scanning just that area where the aircraft is, greatly increasing the frequency of the signal. That lets the aircraft which can also detect the scanning know there is increased interest."
],
"score": [
6,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fjfvus
|
The “earn it” act
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkmrfmq",
"fkmrqme"
],
"text": [
"**End to end encryption**: stuff like whatsapp, signal, and other apps use it so no one but send and receiver can read messages. There's some cool math behind it. **The Bill**: there's a [bill]( URL_0 ) in the Senate (S. 3398, EARN IT Act of 2020), introduced by Lindesy Graham (R-SC), but with support from Sen. Blumenthal (D-CT). It has a long way to go before getting passed (currently is just got introduced, is maybe in the Judiciary Committee). The bill is aimed at making online child sex trafficking harder by establishing a commission with some executive agency heads directing it. One of their mandates is to establish best practices for internet platform owners to reduce trafficking. While the bill itself makes no specific mention of encryption, there is reasonable concern that parts of the government what a way to reliably read encrypted messages, known as a backdoor. The fear is that an intentionally inserted backdoor will be exploited by malicious actors eventually. For example, an NSA backdoor in an algorithm called Dual_EC was taken advantaged of by bad actors at one point. **The Dilemma**: It's a tricky conundrum. Encryption makes law enforcement's job hard, but making it easier for them reduces the strength of encryption for everyone and gives government some pretty intense surveillance powers. The FBI once broke into an iPhone without Apple's help and it caused some uproar because they never disclosed how they did it. There are people in law enforcement who genuinely just want to solve some of the most heinous crimes imaginable. But other governments use surveillance as part of how they perpetrate some other truly awful crimes, and people's fears of unbounded government surveillance aren't unfounded. **Bonus Round**: There's another component of the bill looking at a company's responsibility, legally, for what other people put on their website. The lever proposed to force their weakening of encryption is to make them liable, which would also be tough. On the one hand, they should be somehow responsible right? But on the other, completely responsible? Imagine reddit having to find a way to keep all posts of a certain type off it's platform--could be a technical challenge, not to mention an absolutely gargantuan and unprecedented legislative and administrative burden. It too is a tricky dilemma, similarly affected by [H.R. 1865]( URL_1 ), a house bill fighting online sex trafficking. Both bills have good upfront motivations but can easily turn into something very dangerous. I'm not sure which side I fall on yet. Informative article on the topic that takes an anti-S.3398 stance [here.]( URL_2 ) Another article [here.]( URL_3 )",
"URL_0 There is a good overviews of the aim of the act. removing end to end encryption entirely, it may help trace individuals that do exploit children sexually. But, it is also a key part of normal people going about their business. Privacy has become a thing of the past through network carriers. Your texts can be read, your calls can be traced. So people turned to web-based services to have private conversations. Now the government want to end that too. Apps like WhatsApp, use end to end encryption. Which means the phone that sends a message, and the phone that receives it, are the only devices capable of reading that message. The encryption isn’t shared anywhere else. And WhatsApp themselves don’t know what you’re sending. You can see how that could be abused by certain groups. (Including pedophiles). But it is also used day to day by millions of innocent people, who just want their privacy. (Grown adults consensually sexting for example). The bill brings up some absolutely valid points, but it also aims to break the privacy of those millions of innocent people, to catch a few disgusting pieces of shit. I am vehemently anti-pedophile. I applaud the bill. I applaud what it is trying to achieve. But I think there are less invasive ways to achieve it. Not really a topic for a 5 year old, but I hope it helped."
],
"score": [
10,
6
],
"text_urls": [
[
"https://www.congress.gov/bill/116th-congress/senate-bill/3398/related-bills?q=%7B%22search%22%3A%5B%22earn+it%22%5D%7D&r=1&s=1",
"https://www.congress.gov/bill/115th-congress/house-bill/1865",
"https://nakedsecurity.sophos.com/2020/03/13/earn-it-act-threatens-end-to-end-encryption/",
"https://www.forbes.com/sites/zakdoffman/2020/03/14/new-warning-issued-for-all-whatsapp-and-imessage-users-major-threat-to-encryption/#5e1366bc53f5"
],
[
"https://www.judiciary.senate.gov/press/rep/releases/graham-blumenthal-hawley-feinstein-introduce-earn-it-act-to-encourage-tech-industry-to-take-online-child-sexual-exploitation-seriously"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
fjhw0c
|
what does a relay card do exactly? (Electronics)
|
The best definition I could find online is: These handy boards provide a simple method to interface a low level control output from a control system such as the FSR Flex Gpio ports to higher level loads such as a low voltage screen controller. They can also be used to reverse control output logic if necessary **can someone break this down in layman’s terms?**
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkn3uo1"
],
"text": [
"A relay is a physical switch that is controlled by an electric current. So a relay have two different sides to it. There is the control side and there is the switched side. The control side have two pins while the switched side typically have three pins but can have a different number of pins depending on what kind of switch it uses. The relay is used to seperate two circuits from each other. As there is no electronic connections between the controll side and the switched side nothing on the switched side can affect the signals on the controll side. The circuit is galvanically seperated. That is of course assuming you stay within the limits for voltage and current of the relay. Relays are often used in control circuits to allow a low current low voltage signal control a high current high voltage load. For example the GPIO pins on a microcontroler might not output enough voltage or current to power motors, heaters, lights, etc. However they might have enough output for a relay which can then switch the load on or off. For example you can apply a 3.3V 100mA signal on the control side to switch on a 24V 5A light on the other side of the relay. It is also possible to use the relay the other way around, having a high voltage signal power the relay to give a low voltage signal to the microcontroller. This is an alternative to a voltage divider or an optoisolator but offers greater degree of isolation so you are guaranteed that the high voltage never reaches your microcontroller."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
fjoezd
|
How do telephone wires carry multiple messages at once? How do messages not interrupt each other?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkoaofl"
],
"text": [
"The analogy is to consider listening to music say from a band or orchestra. All the instruments send their sound messages through the air. It is still possible for us to discern between a drum and a guitar and a piano - and very likely hear the different notes they are playing even though they sound at the same time. In a similar way, multiple messages can be encoded on a single wire and with the proper filtering at the receiving end, these messages can be \"heard\" separately. This happens all the time with analog radio (for example). All the radio signals from all the stations are present everywhere and the radio is designed so that you can \"tune in\" to a particular station and ignore the others. With digital, there is even more ability to interleave messages and use digital processing to de-interleave the received digital data into various streams which is why one internet cable can simultaneously support multiple devices browsing, streaming, gaming etc."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fjog88
|
Why do write speeds vary drastically when copying another file unto a USB stick?
|
Whenever I copy a file onto a USB, it starts at 30MB/s then goes down to 20, then 10, then 8 and sometimes and even 2MB/s and stays there. What is happening to the drive that the write speeds decrease so much?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fko7lzo",
"fkozqio"
],
"text": [
"Writing dense flash memory is slow. Writing cheap dense flash is *very* slow. Some USB drives get through this by having a bit of faster memory between the big NAND and the PC so you can copy small amounts of data fast (and it filters onto the slow memory with time). Except when you dump data onto the drive the fast memory fills up and then the speed drops/stops until the slow memory accepts the data. Depending on how the drive works you might see waves in the speed as the fast memory is emptied and the PC fills it up quickly.",
"Software developer here, It's not the hardware to blame for the transfer rate you *see* dropping, but the software used to compute the running average, and display it to you, is very time sensitive. The transfer started, statistics started getting collected, and there was a lag between the work and the first update of the display. What you get is a skewed output. The truth is no one cares enough to fix the code to display a more correct initial value - the algorithm will correct itself over time and settle onto an actually reasonable approximation. Why is it slow in the first place? Well that depends on a number of factors. USB is a packet network, just like Ethernet, though it doesn't typically leave the confines of your machine. There are 3 major versions, and each have their performance consequences. Just because a device says USB 2.x or 3.x DOESN'T ACTUALLY MEAN it uses those protocols - all they're advertising is you can plug into that interface, and it'll work. So all your cheap devices may be running the 1.x protocol for all we know. And your USB hub is sharing bandwidth with your South Bridge, which means all your other peripheral busses, and how much traffic are they generating on your motherboard?"
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fjs4cv
|
How can barcodes have a small amount of squares and we still don't run out of barcodes?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkooy7z"
],
"text": [
"Bar codes are just a computer-readable version of the number that's written below the barcode. So there's as many possible barcodes as there are numbers with that many digits. UPC codes are 12 digits long, so there's about 1 trillion possible codes."
],
"score": [
15
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fjslx2
|
why are consoles so much cheaper than building/buying prebuilt normal computers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkorot7",
"fkorwja",
"fkp45od",
"fkowk7u",
"fkortor",
"fkosba8"
],
"text": [
"Economy of scale and Xbox/PS doesn’t expect to turn a profit on the consoles alone. Licensing rights, fees from marketplace, subscriptions, game fees, etc make up the bulk of their revenue. Think about how much you spend on games over the life of a console.",
"Because they are sold at a loss, Microsoft and Sony make their money back by forcing you to pay for subscription services and licensing fees they charge on games. After the console matures the price of production drops many times before the price of the console drops. They also have the luxury of a massive economy of scale.",
"As everyone else said, but also the fact that it will probably have none of those stats. Remember, the PS4 was supposed to do 4K 60 FPS when first rumored/announced - the pro version doesn’t even do that at all.",
"Building a pc with the specs of these consoles won't cost $1000. The gaming pc I built a few years ago for about $1000 is still more powerful than the coming systems.",
"Economy of scale, they make millions of units. Also, these can be a loss leader for companies like Microsoft who make money on every game sold. Sell the console at a $50 loss and make $5-15 per game",
"A number of things. For one, computers are designed to do a much larger amount of stuff than a console. Even if a particular console and a particular desktop computer have the same graphical capabilities the computer is *still* going to have to do a lot more non-gaming related stuff. All that extra capability costs money. Second, economies of scale come into play with consoles. Microsoft is going to build *a* *lot* of these things, so they individually dont have to be priced as high for the company to turn a profit. Also, its entirely possible Microsoft is willing to accept taking a loss on the consoles if they believe the accessories (games, Xbox Live) will make up the diffrence. Long story short: Computers and Consoles are built with different goals and economic outcomes in mind."
],
"score": [
28,
10,
8,
5,
5,
4
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fjv1p2
|
What ultimately causes batteries to completely die?
|
Some batteries that sit in unused electronics for an extended amount of time don’t hold charges anymore. So is it better to periodically charge electronics that aren’t used regularly just to keep the battery from losing its useable life? Or is it reasonably just a matter of time before batteries aren’t reasonably usable?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkpi8xp",
"fkp7ide",
"fkpimg5"
],
"text": [
"Batteries are basically a little block of material rusting in order to make electrons move. One that little block of material rusts completely, or at least enough that no more if it can rust, it can't make electrons move anymore. As long as there is any connection between the two ends of the battery, even a bit through the inside of the battery, it's rusting in order to make electrons move along the connection. Rechargable batteries are different because we can reverse the flow of electrical to reverse the rusting, restoring some of the material to it's original condition. This always it to rust again in the future to supply electricity. But the reversing process isn't perfect, so the amount of material that gets restored decreases with each charging cycle, if only a little bit. If the amount of material available gets small enough it won't be able to push as many electrons as hard as it used to when it rusts, and possibly not enough or hard enough to make the device it's attached to run anymore.",
"most electronics these days draw a very small amount of current to keep standby power running for things like built in clocks, wifi or GPS if they are enabled. Batteries will also self discharge if the casing of the battery is dirty which will cause a small amount of current to flow from the negative terminal to the positive terminal. Chemical reactions inside the battery will also cause them to self-discharge.",
"The answer to your question varies. There are just a bunch of types of batteries. The chemical reaction that is used in liquid-filled batteries (like used to be in car batteries) is one of the oldest chemical reactions known to man. **Understanding this one is the easiest way to understand all the others.** In this reaction there are two pieces of metal. The important thing is they're not the same kind of metal. The metal pieces both hang in a tub of acid (or alkaline, depends on the battery). **The metal is being slowly dissolved by the battery.** As this happens, little hunks of metal float over to the other piece of metal. They get stuck. This is called electroplating. This is how ancient smiths plated things. We've been doing this for as long as we've been making things of metal. Humans figured out that if you touched the other piece of metal - the one being covered - you got a brief shock. We eventually figured out stuff we could do with that shock. That led to ways we tried to get a more consistent shock instead of a burst of shock. Now we have tons of types of batteries, with a bunch of different ways they all do essentially the same thing."
],
"score": [
16,
11,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fk9hhq
|
How do apps that identify songs work?
|
Pretty much the title, for example, you can ask Siri “what’s this song?” And even over a crowd of loud people, she can do it in seconds. It boggles me.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkreqlc",
"fkszvma"
],
"text": [
"You have a bunch of blocks you like to play with. Some are big, some small. Some have patterns, others are solid colors. If I took one and placed it really far away from you so that you can just barely see it. And told you, guess which block it was. You'd have to see if there was a predominant color or pattern, even though you can't see the whole block. So you can kinda make out that the block is blue ish, but some yellow mixed in. That might match one or two of the blocks:. A blue sky with a yellow sun, or a blur ocean with a yellow fish. So whichever one looks the most similar, that would be your guess.",
"Things in sound waves that can be detected using software. Peaks in sound waces Tempo Bass frequencies Volume (fullness) changes Very few songs have the same sound wave shape for longer than several seconds. Go look at songs on URL_0 . They have them displayed in \"Soundwave\" format. You can see the peaks and valleys. Oh, also, it's a good time to note that all sounds come together and hit your single eardrum as one sound, from there, our brain separates them out as individual noises based on previous experiences with those sounds. Trippy huh? Edit: List spacing"
],
"score": [
19,
4
],
"text_urls": [
[],
[
"soundcloud.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
fkecvu
|
Why are so many 'Official' youtube music videos from 2000-2010 in 360p or 240p?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fks7ipr",
"fks7mmk",
"fks8zj8"
],
"text": [
"Because that's the best the average person's internet connection could muster back in the day.",
"It wasn't always possible to upload HD videos to YouTube. It's a feature they added later on. In the beginning, I think only 240p and 360p were available, and if you uploaded a video with a higher resolution, it was automatically downscaled.",
"The internet wasn't very fast then, so video and music had to use smaller file sizes to compensate. Smaller file size = lower quality. Also a lot of those early YouTube videos were on various websites and file sharing platforms before YouTube, so some are even older."
],
"score": [
25,
15,
7
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fkskad
|
How do photos of space matter produce all the colors?
|
Such as photos of nebulas or galaxies. I remember something about using filters of different gases but that’s it.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkuktcg",
"fkukqrm"
],
"text": [
"Most photos of nebulas or galaxies are made using light our eyes can't see (like infrared or UV). Their \"colors\" are remapped to colors we can see, so we can actually look at them. This is an artistic process as there is no \"correct\" way to map colors we can't perceive to color we can, which is why space photos are usually that colorful.^[1] Some pictures taken using visible light also have their colors remapped, just so that they look better. (There is nothing special about visible light -beside the fact that we can see it- so the process makes sense for it too). [1] In some cases you can still find raw version of these images, without the recoloring, but these are just arrays of values, so you'll have to remap them yourself, or just use them as is.",
"In a few different ways, depending on the purpose. 1. they are digital colored to make them striking and beautiful. to varying degrees this _may_ be done consistent to number 2, below. 2. different data is color coded. For example, many \"telescopes\" aren't looking at visual spectrum at all, so to make it useful to our eyes data is color coded. this is a sort of \"translation\"."
],
"score": [
8,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fktng0
|
How do pointers in C++ work, and why are they different from references?
|
Edit: Perhaps I mean "how" are they different from references, not why.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkuqx8j",
"fkv59cd"
],
"text": [
"A pointer is simply a variable that holds a memory address. You can pass a pointer to a function, which allows you to modify the contents of that memory address without having to return anything. A reference is similar. Normally when you pass a variable to a function, it's passed *by value.* This basically means that the function gets a copy of the variable. If the function modifies the copy, it doesn't affect the actual variable. However, C++ also allows passing *by reference*, which passes the actual variable to the function, not just a copy. This allows the function to modify the variable. In the code below, the first *cout* statement will print \"5, 6, 7\" while the second one will print \"5, 8, 10\". The x parameter is an integer passed by value, y is an integer pointer, and z is an integer passed by reference. #include < iostream > using namespace std; void modify(int x, int* y, int & z){ x += 1; *y += 2; z +=3; } int main() { int a = 5; int* b = new int; *b = 6; int c = 7; cout < < to_string(a) + \", \" + to_string(*b) + \", \" + to_string(c) < < endl; modify(a, b, c); cout < < to_string(a) + \", \" + to_string(*b) + \", \" + to_string(c) < < endl; return 0; }",
"A pointer is a variable that holds a memory address. Your business card is a pointer, it tells me your address. Knowing that doesn't tell me who's in your house, I just know where to look if I want to know who's there. Deferencing is like taking my knowledge of your address and using to drive to your house, go inside, and see who's there. A reference is basically an always dereferenced pointer. You're always looking through the reference at the value of the referenced variable."
],
"score": [
13,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
fkzao9
|
How do photographers make the moon look huge, when it does not to the naked eye?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkvo88f"
],
"text": [
"they're using telephoto lenses aka \"zoom\" lenses so further away objects look closer. and then they frame the moon so that it takes up the entire sensor so that it looks big."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
fl9zrg
|
How can we warm things like food up (ovens) and cool them down (freezers) with electricity?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkxcn16",
"fkxcteo"
],
"text": [
"Electricity and heat are both energy, although different *forms* of energy. Heating and cooling works slightly different, though. In an oven, electricity is converted to heat by running it through a wire with a high resistance. This causes energy losses in the form of heat, which dissipates out into the oven, heating the food. Simply put, we convert electrical energy into heat. In a freezer, we use the electricity to run a system of pipes and valves. Through some clever engineering, we can force a liquid called refrigerant to evaporate into a gas and the condense back into a liquid. When this happens the refrigerant, because of how our universe works, *has* to take in or give away energy. By taking in energy inside the freezer and giving it away outside the freezer, we can move the heat from inside the freezer to outside the freezer. This is why the back of your freezer is warm and shouldn't stand directly against the wall! Edit: Spelling.",
"Ovens create heat by burning gas or moving electricity through special wire that turns it into heat. Freezers make things cold by a neat trick certain chemicals do, where you can pressurize and de pressurize them in such a way that they actually move a substantial amount of heat. So you can move heat from inside the freezer to outside of it, which makes it cold."
],
"score": [
33,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
flehmz
|
how do magic eye pictures work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fky8xrc"
],
"text": [
"Depth perception works by your eyes receiving slightly different images and extracting distance information from that. Magic Eye images use repeating patterns to fool your brain to think your eyes are focusing on a single point that's actually two different points on the page (these two points are about 1-pattern cycle apart). This allows your brain to overlay the page on itself at an offset, creating the differences needed for depth perception. Fun fact: If you can manage to focus on a point *closer* than the page, you can perceive a depth-flipped \"negative\" version of the image."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
flfv4c
|
Why does text in screenshots often have a pixelated area around it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkycepo"
],
"text": [
"Those are [compression artifacts]( URL_0 ). Lossy image compression such as JPEG are designed to work best when neighboring pixels have similar colors, as usually happens in natural photos. On the other hand, they are bad when there are sharp transitions in color, for example in software screenshots and in text. The result is a compression artifact, basically the black color \"bleeds\" into the white and vice versa."
],
"score": [
5
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Compression_artifact"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
flkr4o
|
how were aerial photos possible as early as 1860's in areas where they had no hills or mountains overlooking the city?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkz4jjt",
"fkz83h0"
],
"text": [
"It's going to be really hard to stretch this out. But in the 1860's they had hot air and gas balloons.",
"Hot air balloons were used in 1870 in the Prussian French war. The Prussians besieged Paris and the only way Parisians had to watch their enemy was from a hot air balloon. They used it for surveillance as well as taking arial photographs."
],
"score": [
11,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
flm1nz
|
What is a server?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fkzcds4",
"fl0a6et"
],
"text": [
"A server is a computer that services requests from other computers, referred to as clients. Those requests could be to send a particular webpage back to the client, to perform a calculation, to retrieve or store some data in a database, whatever.",
"A server is a computer which has a program which answers messages from other computers. You want to go to Reddit, so your computer looks up the address of one of Reddit's servers and sends it a message (think of a virtual postcard) saying \"Hey Mr Reddit Server, can you tell me what's on the front page today?\" And it sends one back saying \"Hey Mr Someone's Computer, there's a bunch of stuff about coronavirus and Trump, .....\""
],
"score": [
10,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
flreyl
|
Users who do game programming with Unity and C#, what is a float?
|
Edit: Thanks for the explanation guys! The different analogies you guys give really helps me to understand it from different perspectives. I am a beginner programmer who just started using Unity yesterday, though I have a little bit of experience with C#. I tried to follow a couple of tutorials to design a 2D game. Most of them use float to declare their player's attack range or other functions (such as [this]( URL_0 ) tutorial at 7:35). I tried searching online for the definition of float and went through several websites and posts, but I still have no idea what a float is, and how it compares to other data types like integers or decimals, and why attack range requires a float data type.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fl18q5i"
],
"text": [
"It's a special kind of decimal where the decimal point \"floats\" around the number, allowing it to represent numbers that are bigger and smaller than you would be able to otherwise. Say you had a piece of paper and you could only fit 10 numbers on it. You divide it into 10 boxes, like this: xxxxxxxxxx - the xs can be any number between 0 and 9 What's the biggest number you can represent? 9999999999 - because if you were to go any higher, you'd need an extra box, and go off the side of the paper. Okay, how could we represent a decimal number? We could agree beforehand that the decimal point goes in the middle of the paper, like this: xxxxx.xxxxx But what is the largest number we can write now? 99999.99999 - because the decimal point is in the middle, we only have five spaces on each side. We've cut the maximum size of the number by a factor of 10000! Okay, let's find a better way. What if, instead of putting the decimal point in a fixed spot, we reserve one of the boxes and use it to position the decimal point wherever we want? Like this: p xxxxxxxxx To figure out what decimal number we're talking about, we look at the value of p and count that many spaces from the first x number. That's where we put our decimal point. For example: 5 999999999 means count 5 spaces from the first 9, giving us 99999.9999 Now we can represent any number between 0 and 9999999, and they can be decimals too! The only problem is that when we pick really big numbers, we run out of space on the right to fit the decimal bit in. That's what causes game physics to start breaking when you're really far from the middle of the map."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
flvag6
|
Why do some sites check my browser before giving me access to it ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fl0oxtj",
"fl1e6ie",
"fl0p3zk"
],
"text": [
"Cloudflare is usually the one doing this. The purpose is to lock out \"users\" that the site doesn't want. Usually bots, web crawlers, and things of that nature. It also protects against things like DDOS attacks and other web based denial of service stuff. Or, super TLDR version, it's making sure you're an actual user with an actual browser, not a script sending traffic.",
"The other comments have already covered the purpose of this, but I thought I'd add some technical insight. The anti ddos provider (typically cloudflare) asks you to submit a so called proof-of-work. They send your browser a really hard math problem, that it takes it a few seconds to figure out. It won't let you visit the actual website before you solve the problem, so it protects the website from all visitors that cannot spare a chunk of computing power. Because computing power is pricey, a spam attack has now become so expensive that it is practically impossible. A real ddos attack requires thousands of \"visitors\" which would require thousands of these proofs of work, as the math problem is different for each user. The only cost is that regular users have to wait for a few seconds. The same concept has been used to combat email spam (hashcash) and is what makes all the big crypto currencies work.",
"You're probably referring to DDoS protection (like cloudflare). A Distributed Denial of Service attack is when a person or group of people set up a network of \"hacked\" computers called a botnet and use them to generate traffic to one website or service at a time, overloading the network capacity of the service and causing it to be unaccessible to legitimate traffic. When you see a message that your browser is being checked, the service is just determining that you are not part of one of those attacks. It does not mean that an attack is currently going on, btw."
],
"score": [
56,
11,
6
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
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